THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS STATE OF CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF ENGINEERING AND IRRIGATION EDWARD HYATT, Stale Engineer BULLETIN No. 14 CZ AZ The Control of Floods by Reservoirs By PAUL BAILEY AN APPENDIX to the SUMMARY REPORT TO THE LEGISLATURE OF 1927 on the WATER RESOURCES OF CALIFORNIA * and a Coordinated Plan for Tlieir Development l-IBRARY 52411 (UNIVERS. 1 Y OF CALIFORNIA PA VIS TABLE OF CONTENTS Page FOREWORD 5 ENGINEERING ADVISORY COMMITTEE 7 ORGANIZATION ^ 8 LIST OF PLATES 10 LIST OF TABLES 11 Ohapter I. OPPORTUNITY FOR CONTROLLING FLOODS BY RESERVOIRS 13 Past consideration given to control of floods by reservoirs 13 Future conditions favorable for use of reservoirs in controlling floods 14 Physical opportunity to combine conservation and flood control in same reservoir 14 Chapter II. SYSTEMS OF FLOOD CONTROL 18 Leveed channel system 18 Reservoir system 18 Combined reservoir and leveed channel system 19 Degree of protection in flood control systems 20 Frequency of flood occurrence 21 Chapter III. THE PRINCIPAL CHARACTERISTICS OF FLOOD OCCURRENCE 27 Regularity of flood occurrence 27 Time of year of flood occurrence 27 Limiting dates to the flood season 29 Date of greatest flood expectancy 36 Preparatory precipitation for flood occurrence 36 Limiting values of progressive rainfall index between which floods occur 41 Most favorable value of progressive rainfall index for flood occurrence 49 Relation of flood occurrence to season's run-off 50 Chapter IV. RESERVOIR SPACE REQUIRED TO DETAIN EXCESS FLOOD FLOWS 53 Source of information 53 Method of analysis 53 Relations established 58 Values determined 60 Variation in values with time of year and progressive rainfall index 62 Chapter V. THE RESERVOIR OPERATING DIAGRAM FOR CONTROLLING FLOODS.— 73 Principles of oi^erating reservoirs for controlling floods 73 The reservoir operating diagram 74 Reservoir operating diagram for controlling floods on Sacramento River 77 Reservoir operating diagram for controlling floods on Mokelumne River 81 Reservoir operating diagram for controlling floods on San Joaquin River 85 Reservoir operating diagram for controlling floods on San Gabriel River 87 Performance of the four illustrative reservoir operating diagrams in con- trolling floods, not coordinated with conservation 90 (3 ) TABLE OF CONTENTS— Continued Chapter "VI. Page EFFECT ON CONSERVATION OF CONTROLLING FLOODS BY RESERVOIR OPERATING DIAGRAM 98 Effect determined by direct test 98 Kennett reservoir on Sacramento River 99 An alternate rule for controlling floods by reservoirs 105 Pardee reservoir on Mokelumne River 118 Temperance Flat reservoir on San Joaquin River 128 San (Jabriel reservoir on San Gal)riel Iviver 138 Performance of the four illustrative reservoir oi)erating diagrains in con- trolling floods when coordinated with cf)nscrvation 198 Chaptkr VII. CONCLUSIONS 207 Relialiility of analyses 207 Accuracy of analyses 210 Effect of length of stream flow record upon accuracy of deductions 210 Geograi)hical limitations of system of anaylsis 211 Future possibilities of improving proposals for control of floods by reservoirs 211 Chapter VIII. TABLES OF MONTHLY SUMMARIES OF WATER AND POWER YIELD OF RESERVOIRS ON THE FOUR ILLUSTRATIVE STREAMS 21.'; ( 4 ) FOREWORD. This bulletin is one of a series api)ended to the "Summary Report on the Water Resources of California and a Coordinated Plan for their Development" that was presented to the Leg^islature of 1927. It is part of the investigation of the water resources of the state conunenced in 1921. This invest ig'ation has comprised a survey of water supplies and flood flows throuj^hout the state, a determination of their cliaracter- istics, an estimate of tlie present and future nee:ls for water, and the formulation of a comprehensive and coordinated plan for future development in order to insure adequate water supplies for all purposes. The 1927 report concludes this investigjation. The entire series of bulletins pertaining to the 1927 report are : Bui. 12 — "Summary Report on the Water Resources of California and a Coordinated Plan for their Development." (A rejiort to the Legislature of 1927.) Bui. 13 — "The Development of the Upper Sacramento River." Bui. 14— "THE CONTROL OF FLOODS BY RESERVOIRS." Bui. 15— "The (Viordiiuited Plan of Water Development in the Sacramento Valley." I'.ul.lG— "The Coordinated Plan of Water Development in the San Joaquin Valley." Bui. 17 — "The Coordinated Plan of Water Development in Southern California. ' ' Other bulletins pertaining to these investigations published prior to the 1927 report are : Bui. 4 — "Water Resources of California." (A report to the Legislature of 1923 on the first two years of investiga- tion.) Bui. 5 — "PloAv in California Sti-eams. " Bui. 6 — "Water Requirements of California Lands." Bui. 9 — "A Supplemental Report on the Water Resources of California." (A report to the Legislature of 1925.) Bui. 11 — "Ground Water Resources of the Southern San Joaquin Valley." The first appropriation for the investigation of the Avater resources of California was made by Chapter 889 of the 1921 Statutes, in the amount of $200,000. This resulted in the publication of Bulletins Nos. 4, 5, and 6. These contain a complete inventory of all the waters within the State's boundaries, an estimate of the future needs of water for all purposes, and a preliminary comprehensive ])lan for ultimate development that will secure the greatest public service from tlie State's limited water supply. No provision was made for tlie continuance of tlie investigations by the 1923 legislature but at the urgent request of the farmers of the southern San Joaquin Valley, the Cliambei-s of Commerce of San Fran- cisco and Los Angeles advanced $90,000 for the study of a first unit ( 5 ) of the comprehensive plan that would relieve the stress in a section of the State most in need of an imported water supply. With this money, works were planned tliat would transport tlie surjdus waters of the Sacramento drainage basin into the San Joaquin Valley and make a new supply available for the southern half of the valley. An account of this work is published in Bulletin No. 9, a report to the Legislature of 1925. Chapter 477 of tlie 1925 Statutes made $150,000 available to the Division for completion of the work. This money was spent in perfecting the "Coordinated Plan" of development rerpiested in the appropriation bill. Heretofore, in looking to the future, the problems of flood con- trol and of conservation have been given se])arate consideration. Expen- sive construction programs are known to be necessary in both fields of endeavor to provide habitable conditions for the increasing population. The investigation of the possibility of coordinating these two necessary programs has assumed such large proportions that this entire volume has been given over to the presentation of this phase of the "Water Resources Investigation." (6) ENGINEERING ADVISORY COMMITTEE. This bulletin was prepared in consultation with a committee of engineers who advised in the working out of the "Coordinated Plan." They are : Louis C. Hill B. A. Etcheverry J. B. LippiNCOTT F. C. Herrmann Wm. Mulholland Walter L. Huber A. J. Cleary a. Kempkey G. A. Elliott Cooperating with committee: P. E. Bonner, District Engineer, U. S. Forest Service, representing the Federal Power Commission in California. A. V. GUILLOU, Assistant Chief Engineer, State Railroad Commission. L. S. Ready, Formerly Chief Engineer of State i^ailroad Commission. C. S. Ridley, Major, Corps of Engineers, U. S. Army, member and secretary of California Debris C^ommission. ( 7) ORGANIZATION. B. B. MEEK Director of Public Works EDWARD HYATT Siate Engineer This bulletin and the "Summary Rei)ort on the Water Resources of California and a Coordinated Plan for their Development" were prepared by Paul Bailey* A. D. Edmonston, Princi])al Assistant T. B. Waddell William S. Post A. N. BuRcii Gerald Jones C. B. Meveu J. II. Peaslee R. L. Wing Chief Assistants Percy Jones A. M. Wells Chester Marliave J. J. Haley, Jr. Senior Office Eiigincrrs AV. A. Perkins E. W. Case G. Stttbblefield Jiniior T. Neuman L. C. JOPSON E. W. Roberts IT. B. GiLROY L. N. Clinton C. W. Roberts Laura Munson Thomas Clausskn B. A. Reber A. W. Reber L. E. Anderson P. T. Alexander C. P. Marshall William J. O'Connell II. M. Sturges Harold White F. Ij. Blair II. S. Marshall Office Enghieers Oscar Blumberg J. R. Jahn D. S. Hays A. P. Bosworth J. R. Meskimmons W. A. Dorcas H. Gerharz J. H. Knapp M. II. Blote p. ii. lovering Thomas Lewis W. R. McLean P. W. Porter II. N. SULLIGER V. GiVAN J. H. McCoRMICK D. S. Cleavinger II. L. Butler Delineators Jos. T. Maguire E. N. Sawtelle C. L. Greene J. W. McPartland • Pornu rly Director of Public M'orks and Slate Engineer (lesiKncd Aupriist 'ii. 1027). Mamisrript c()nii)l<'tod for publication, after resignation, through courtesy of B. B. Meelt, Director of Public Work.s. ( S ) Field Engmeers and Topographers H. S. Williams F. L. Elam E. D. Stafford J. H. Gibson J. F. Taylor Millard Dawson C. C. Vance Ray Vernon Glenn Lang Ward Eisan D. E. Prazier Engineering Aids F. L. Firebaugii E. H. Ford C. W. Frazier George Garlinghouse C. R. Hagberg C. A. Harper Leslie Helgesson D. J. Stout . J. G. Meyer W, J. Feeney S. E. Perkins E. R. HiNNANT G. R. King F. Montealegke Cleo C. Osborne D. G. Spellman Dewey Turner G. Zucco H. Neuman R. H. Wight W. L. Pease ( 9 ) LIST OF PLATES Plate No. Paoe I. "Hydrographs of Year of Greatest Recorded Flood", 16 II. "Probable Frequency of Flood Discharge" 21 III. "Plot of All Floods of Record — Years Superimposed" 28 IV. "Relation of Time of Year to Flood Occurrence" — Sacramento and San Gabriel Rivers 30 V. Same — Mokelumne and San Joaquin Rivers 32 VI. "I'rogressive Rainfall Index at Time of Flood Flow" 42 VII. "Relation of Progressive Rainfall Index to Flood Occurrence" — Sacra- mento and San Gabriel Rivers 44 VIII. Same — Mokelumne River 45 IX. Same — San Joaquin River 46 X. "Reservoir Space Required to Control Floods" — Sacramento and San Gabriel Rivers - 55 XI. Same — Mokelumne River 56 XII. Same — San Joaquin River 57 XIII. "Relation of Time of Year to Need of Reservoir Space" — Sacramento and San Gabriel Rivers 63 XIV. Same — Mokelumne and San Joaquin Rivers 64 XV. "Relation of Progressive Rainfall Index to Need of Reservoir Space" — Sacramento and San Gabriel Rivers 65 XVI. Same — Mokelumne River 66 XVII. Same — San Joaquin River 67 XVIII. "Reservoir Operating Diagram for Controlling Floods on Sacramento River — ^Maximum Controlled Flow Near Red Bluff — 125,000 Second- Feet" , 76 XIX. "Reservoir Operating Diagram for Controlling Floods on Mokelumne River — Maximum Controlled Flow Near Clements — Rain-Water Floods 5,300 Second-Feet, Snow-Water Floods 7,100 Second-Feet__ SO XX. "Reservoir Operating Diagram for Controlling Floods on the San Joaquin River — Maximum Controlled Flow Near Friant — Rain- AVater Floods 10,700 Second-Feet, Snow-Water Floods 14,200 Second-Feet" 84 XXI. "Reservoir Operating Diagram for Controlling Floods on San Gabriel River — Maximum Controlled Flow Near Azusa 1,900 Second-Feet" SS XXII. "I'erformance of Reservoir Operating Diagrams in Controlling Floods of Record" 96 XX II I. "lOffect of Controlling Sacramento River Floods Upon Stage of Kennett Reservoir" . 101 XXIV. "Effect of Controlling Mokelumne River Floods Upon Stage of Pardee Reservoir" 119 XXV. "Effect of Controlling San Joaquin River Floods Upon Stage of Tem- jierance Flat Rservoir" 131 ^ XXVI. "Effect of Controlling San Gabriel River Floods Upon Stage of San Gabriel Reservoir" 151 XXVII. "Performance of Reservoir Operating Diagram in Controlling Floods of Record Coordinalely with Conservation" 205 XXVIII. "Effect of Omission of the First Half of the Years of Record that Con- tain Five of the Largest Floods on Indicated Reservoir Space Required to Control Flf)ods on Sacra;npnto River Nenr Red Bluff"_ 212 ( 10 ) i LIST OF TABLES YEARLY SUMMARIES OF RESERVOIR YIELDS COMPUTED ON A DAILY BASIS Table No. Page 1. Kennett Reservoir on Sacramento River — Water and Power Yield, Operating Primarily for Power Generation With Incidental Irrigation Both With and Without Flood Control by Reservoir Operating Diagram 108 2. Same — Water and Power Yield, Operating Primarily for Irrigation With Inci- dental Power Generation Both With and Without Flood Control by Reservoir Operating Diagram 110 3. Same — Comparison of AVater Yield, Operating Primarily for Irrigation for Two Methods of Flood Control 112 4. Same — Comparison of Water and Power Yield, Operating Primarily for Power Generation With Incidental Irrigation for Two Methods of Flood Control 114 5. Same — Summary of Power Yield by Years Both AVith and Without Flood Control 116 6. Pardee Reservoir on Mokelumne River — Water and Power Yield Both With and Without Flood Control by Reservoir Operating Diagram 124 7. Same — Comparison of Water and Power Yield for Two Methods of Flood Control 12(i 8. Same — Summary of Water and Power Yield by Years Both With and Without Flood Control 128 9. Temperance Flat Reservoir on San Joaquin River — Water and Power Yield E'oth With and Without Flood Control by Reservoir Operating Diagram 134 10. Same — Comparison of Water and Power Yield for Two Methods of Flood Control 136 11. Same— Summary of Water and Power Yield by Years Both With and AVith- out Flood Control 13S 12. San Gabriel Reservoir on San Gabriel River — AA'ater Yield Under "Coordi- nated Plan," Flood Control and Seasonal Storage Coordinated 158 13. Same — AA'ater Yield Under "Coordinated Plan," Flood Control, Seasonal and Over-year Storage Coordinated 160 14. Same — Average Size of Flows of Water Yield Under "Coordinated Plan"__ 162 15. Same — Comparison of Water Yield for Two Methods of Flood Control Coordi- nated With Seasonal and Over-year Storage 180 16. Same — Comparison of AVater Yield for Three Steps in Coordinating the Use of Reservoir Space . 182 17. Same — Comparison of Water Yield for Two Sizes of Reservoir Operating for Flood Control and for Constant Draft Only 184 18. Same — Average Size of Flows of Water Yield for Three Steps in Coordi- nating the Use of Reservoir Space 186 (11) LIST OF TABLES— Continued MONTHLY SUMMARIES OF RESERVOIR YIELDS COMPUTED ON A DAILY BASIS Tablp: No. ^'a^^^ la. Kennett Reservoir on Sacramento River — AVater and Power Yield, Operat- ing Primarily for Power Generation With Incidental Irrigation Both With and Without Flood Control by Reservoir Operating Diagram.- 218 2a. Same — Water and Power Yield, Operating Primarily for Irrigation AVith Incidental Power Generation Both With and Without Flood Control by Reservoir Operating Diagram 234 3a. Same — Comparison of Water Yield, Operating Primarily for Irrigation for Two Methods of Flood Control 250 4a. Same — Comparison of Water and Power Yield, Operating Primarily for Power Generation With Incidental Irrigation for Two Methods of Flood Control 266 5a. Same — Summary of Power Yield by Months Both With and Without Flood Control 282 6a. Pardee Reservoir on Mokelumne River — ^Water and Power Yield Both With and Without Flood Control by Reservoir Operating Diagram 300 7a. Same — Comparison of Water and I'ower Yield fur Two Months of Flood Control :<12 Sa. Same — Summary of Water and Power Yield by Months Both With and Without Flood Control ?'2« Oa. Temperance Flat Reservoir on San .Toaquin River — Water and Power Yield Both With and Without Flood Control by Reservoir Operating Diagram 332 10a. Same — Comparison of Water and Power Yield for Two Methods of Flood Control 342 11a. Same — Summary of Water and Power Yield by Months Both With and Without Flood Control 352 12a. San Gabriel Reservoir on San Gabriel River — Water Yield Under "Coordi- nated Plan," Flood Control and Seasonal Storage Coordinated 3G0 13a. Same — Water Yield Under "Coordinated Plan," Flood Control, Seasonal and Over-year Storage Coordinated 382 15a. Saine — Comparison of Water Yield for Two Methods of Flood Control, Coordinated With Seasonal and Over-year Storage 4 04 16a. Same — Comparison of Water Yield for Three Steps in Coordinating the ITse of Reservoir Space 426 17a. Same — Comparison of Water Yield for Two Sizes of Reservoir Operating for Flood Control and Constant Draft Only 448 ( 12 ) CHAPTER I. OPPORTUNITY FOR CONTROLLING FLOODS BY RESERVOIRS. Past consideration given to control of floods by reservoirs. The control of floods by reservoirs has been regarded in the past, generally, as an nueconomic system of protection. However, knowl- edge of reservoir sites in California and of the extent to which they will have to be employed in order that the State's latent resonrces may be utilized, is comparatively recent. The report of the Con.servation Commission* of 1912, although mentioning the necessity of storage, does not list more than a couple of dozen reservoir sites. Not until the water resources investigations were initiated in 1921 has there been general public knowledge of the part reservoirs will play in the future development of this state. It has been pointed out in this work, that a construction program adequate for tlie State's poten- tialities will eventually total 50,000,000 acre-feet or more of reservoir capacity. This will involve the construction of several hundred large reservoirs. More than a thousand sites are now known to exist, more than will be required for a complete development of available waters. Such study as has been given previously to the control of floods by reservoirs indicates that their cost, when constructed for flood control purposes alone, exceeds so far the cost of equivalent protection by leveed channels and by-passes, that only in instances of unusually cheap construction or in the vicinity of metropolitan areas of high property values, can reservoirs be utilized for flood control purposes. In all these studies, either the entire space in the reservoir or some fraction of it, has been allotted to flood control for use only in the temporary, detention of flood flows and to be held empty at all times other than during large floods. Under this mode of operation, the entire cost of the storage space allotted to flood control is chargeable to the protective system. Because this required space is large on important streams, the cost of flood control by reservoirs usually has been found pro- hibitive. The only instances of reservoir construction for flood control purposes in California are the current undertakings of the Los Angeles County Flood Control District and of the City of Stockton. In both of these instances bonds have been voted. Several reservoirs have been constructed by the Los Angeles District. It has been considered by some, without much study, that the con- struction of large reservoirs for irrigation and power purposes will diminish the size of floods. A careful analysis, however, discloses that, unless tliese reservoirs are operated especially for flood control pur- ]ioses. they are apt to be fairly well filled upon the arrival of large floods, because large floods do not occur in seasons of small run-off. While they may absorb many medium and small floods, de])endence can not be placed upon their absorption of large floods. Therefore the va.st program of reservoir construction that will be necessary for domestic supply, irrigation and power, has no particular bearing upon flood * The State Conservation Commission was appointed in 1911 to investigate and report, among other things, on water, the use of water, water power, irrigation and reclamation. ( 13 ) 14 WATEli RESOURCES OF CALIKORNIA. control, unless a special program is devised for its employment for this purpose. That the engineering profession has held the belief that reservoirs would come into more general use in controlling floods, is shown by the report of the California Debris Commission of June 29, 1911. The report of this commission is one of the most extended studies of flood control that has been made in California. The plan of leveed channels i.nd by-passes for carrying off maximum flood flows proposed in this report was adopted by both the California Legislature and the National Congress and is being followed in reclaiming a million acres of overflow laud in the Sacramento Valley. The works are now two-thirds com- ])lete. In planning and recommending the coiistruction of these works, eousideration was given by the California Debris Commission to the 1 eduction of floods by reservoirs. Its conclusions were expressed in the 1911 report as follows: "While favoring the use of reservoirs as far as possible, and considering that one of the advantages of the project herein proposed is that it lends itself to future storage possibilities, tlie conimi.ssion believes that it is not economical to construct reservoirs for flood control, but that such construction should be deferred until these resorvoii-s prove desirable for power and irrigation purposes." Future conditions favorable for use of reservoirs in controlling floods. The time has arrived when reservoir construction is necessary for both power and irrigation purposes. California now stands with a full measure of development of the summer flow in its streams. Further progress involves the storage of winter and spring storm water and its I'etention for summer use. The employment of these reservoirs for flood control, that necessarily will be constructed in succeeding years for irrigation, power and domestic suj^plies, is a matter of great public interest. Its accomplishment would be of inestimable public benefit. The water resources investigation, therefore, has undertaken the inten- sive study of the problem of how flood control might benefit from the construction of reservoirs for other purposes. The attempt to use reservoirs for both flood control and conservation seems at first like a contradictor}' effort. To be useful for regulating floods, reservoirs should be held empty during the period of heavy run-off' in order to be able to absoi-b an excessive flood flow if it should occur, while for conservation purposes, they .should be allowed to fill during this same period in order that the run-oft' season may end with a full reservoir. However, a detailed analysis of the tinu' of occurrence and volume of flood flows discloses a procedure for filling reservoirs that will hold in reserve sufficient cai)acity to absorb floods during the time in which they are likely to occur, and progressively release this space for filling as the end of the flood season approaches. This bulletin is devoted to the j)resentation of these nuitters. Physical opportunity to combine conservation and flood control in same reservoir. That a combination i)rogram of conservation and flood control should be possible seems evident from an examination of the hydrographs of California streams. This discloses that excessive rates of flood flow arr- of comparatively short duration, that they occur in the middle or fore THE CONTROL OF FLOODS BY KESEKVOIKS. 15 part of the period of heavy run-oft', and that the volume of water dis- charged at the extremely high rates is relatively small. The reservoir capacity required to absorb these high rates of flood flow, although large in itself, is still very much less than will be required to e(iualize any great part of the seasonal run-oft' for irrigation use. These general observations are illustrated by the hydrographs of four typical streams, the Sacramento, Mokelumne, San Joaquin and San Gabriel rivers, drafted on Plate I, " PIvdrographs of Year of Greatest Recorded Flood."* On this plate, full-line hydrographs portray the run-oft' tlirougliout tlie year of the greatest flood on record on each of the four streams. A heavy horizontal line crosses each hj^drograph plotted at half the rate of discharge of a large flood which is here taken as one estimated to be exceeded at average intervals of 25 years. (The frequency of flood occurrence is taken up in detail in the second chapter. ) The areas within the full-line hydrographs above the heavy horizontal line, shaded in solid black, represent the total volume of water that would have had to be detained by reservoirs in that season in order to limit the downstream flow to half the rate of a once-in-25-year flood. Superimposed on these full-line hydrographs of the flood years are hydrographs of seasons of normal run-oft' shown by dotted lines. The cross-hatched areas within these dotted-line hydrographs represent the volume of winter and spring run-off that would have to be stored to make the entire run-off of a normal season available for irrigation use. A comparison of the solid black with the cross-hatched area on each figure of Plate I, shows the relative reservoir capacity needed to limit the largest flood of record to half the rate of a once-in-25-year flood and to equalize the entire run-off of a normal season for irrigation use. It may be observed that the reservoir capacity required to cut large flood flows in half is small compared to that required to equalize the entire run-off of a normal season for irrigation use. On the Sacramento, Mokelumne and San Joaquin rivers the one is from 5 to 15 times larger than the other, while on the San Gabriel, a very flashy stream, the reservoir capacity required to equalize the entire run-oft' of a normal season for irrigation purposes is about twice that needed to absorb the top half of a large flood. Since it will be necessary in coming years, on most of the streams of the State, to make the entire flow of normal years available for use in order that deficient w^ater supply may not limit the growth of California, it is seen that the reservoir cai)acity necessary for conservation i)ur]>oses is very much greater than that needed to limit the high rates of flood flow to half that of a once-in-25-year flood, excejit on streams like the San Gabriel River that have exceedingly flashy run-off. Any reservoir or group of reservoirs that have sufficient capacity to store a considerable fraction of the winter and spring run-oft' of a normal year, if not already well filled, could easily al)sorl) the volume of flood water wliich * Water Supply Paper No. 551 of the United States Geolog-ical Survey, recently published, places the maximum di.scharg-e of the Mokelumne River at Clements at 25,500 second feet. This is obtained by applying the rating curve of the 1911 flood to the gage heights of 1907. The crest discharge of the 1907 flood has been pub- lished as 17,000 second feet in foriner publications including Water Supply Paper No. 299 in which are printed the daily discharges of the 19 07 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing this volume. Should the daily discharges of the 1907 flood be revised by application of the 1907 gage heights to the 1911 rating curve, the increase in their values would be so sub- stantial as to require a complete revision of the analyses of floods on the Mokelumne River contained in this volume in order to make the analyses liarmonize with the increased discharge values. 16 WATER RESOURCES OF CALIFORNIA. [>LATE I. SACRAMENTO RIVER NEAR RED BLUFF 1908-1909 MAR. APRIL i MAY RESERVOIR SPACE REQUIRED I. To absorb flows in excess of half rtie maximum flood rate. 2. To make the run-off of a normal >ear available for irrigation. JUNE JULY AUG. / Irrigation draft equal lo normal mn-off MOKELUMNE RIVER NEAR CLEMENTS I9I0-I9II (A C fU V) o SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APRIL MAY JUNE JULY AUG. 50% of 24 hour average of once-in-253iear flooi 6- 4- Year of normal run-off (1921-1922 -RESERVOIR SPACE REQUIRED .^'l. To absorb flows m excess of ■^ half the maximum flood rate. 2. To make the run-off of a normal ^ear available for irrigation. :2E^=i: SAN JOAQUIN RIVER NEAR FRIANT 1910 -1911 SAN GABRIEL RIVER NEAR AZUSA 1915 - 1916 OCT. NOV. DEC. APRIL AUG. ■RESERVOIR SPACE REQUIRED -. — -I. To absorb flows in excess of half the maximum flood rate. 2. To make the run-off of a nomal .jfear available for irrigation. Hydrographs of Year of GREAitr' Rlcorded Flood THE CONTROL OP FLOODS BY RESERVOIRS. 17 otherwise would be discharged at rates in excess of half that of a once- in-25-year flood. Although the volume of flood water discharged at rates in excess of half that of a large flood is relatively small, an inspection of the gen- eral shape of the hydrographs on Plate I reveals that the volume of flood water discharging at rates less than half that of a large flood increases quite rapidly with the lower rates of discharge. This is indi- cated by the increasingly greater widths of the peaks on the hydro- graphs as they descend below the heavy horizontal lines drawn at rates half that of a once-in-25-year flood. At about the quarter points, except on the San Gabriel River, these peaks merge more or less into one another on account of their increasing wddth. This greater width of the peaks on the hydrographs represents increasing duration of flow at the lower rates. The flows delineated by the thin width of the peaks on their upper part are high rates of discharge, the direct result of intense rainfall on saturated or snow-covered areas. Since high rates of rainfall do not continue over long periods of time, the duration of these exces- sively large rates of run-off is brief and the peaks on the hydrographs have a narrow width. As lesser flows are considered, the run-off from medium and low rates of rainfall, which continue much longer, as well as the tardy waters draining oft' the catchment area in the wake of heavy storms, are included to a greater extent and the peaks on the hydrographs have a greater width. The duration of the lower rates of rainfall is so much longer than the duration of the higher rates that much greater volumes of water would have to be detained by reservoirs if floods were to be reduced to as much as a quarter or less of the rate of a large flood than to only a half. A further increase in the volume of water that would have to be detained in order to limit flood flows to much less than half that of a once-in-25-year flood comes from melting snow on those streams a con- siderable part of whose drainage areas extends into high altitudes. As illustrated by the hydrographs of the Mokelumne and San Joaquin on Plate I, fairly high rates of discharge occur from melting snow during May, June and July. The Sacramento and the San Gabriel, the two other illustrative streams, do not have snow-water floods. Unlike the flood discharge from rainfall, that from melting snow continues over rather long periods of time. However, their greatest rate seldom exceeds half that of a once-in-25-year flood, so that they concern flood control only if floods are to be reduced to less than this rate of flow. While the foregoing considerations are very general and are prin- cipally illustrative of the characteristics of stream flow to be analyzed in detail in later chapters, nevertheless, they indicate that the volume of water to be detained by reservoirs would increase very rapidly if an attempt were made to reduce floods to much less than half a onee-in-25- vear flood. The capacity required to do this would be much larger than probably will be constructed on most of the State's streams for many years to come. The relatively small space required to reduce floods to half the rate of a once-in-25-year flood or thereabouts makes it appear, in general, that this would be the possible present utility of conservation reservoirs for controlling floods. A coordinated program of operation for both conservation and flood control would be necessary for this accomplishment. 2—52411 18 WATER JtESOUUCES OF CALIFORNIA. CHAPTER II. SYSTEMS OF FLOOD CONTROL. Leveed channel system. There are, in general, two systems of flood control: one tliat leads flood flows to the ocean in si)ecially i)repared channels without diminu- tion in vohuue, the other that reduces the volume of flow to a harndess amount by detention of excess watei* in storage reservoirs. The first is the system in common use, for it is usually least in cost. The reasonable cost of this system is attained by constructing the greater part of the flood channels above the ground surface. The banks of the channels are formed by earthen levees excavated from adjacent borrow pits. The capacity of the channels is fixed by the spacing and height of the levees. Seldom does the borrow pit from which the levee material is excavated constitute a very large part of the waterway. Even Avhere the leveed channels follow natural water courses, their increased capacity, due to the construction of the levees, is largely in the cross- sectional area above the ground surface. Thus, the safety of the system fests upon the strength of the levees to withstand the water ])ressure and the sufficiency of the carrying capacity of the flood channels. Should the levees fail or be breached by over-topping, a large part of the entire flood volume might run through the breach over the adjacent land. One of the })rineipal reasons for success in this system of protection is the infrequent occurrence and short duration of large floods that tax the strength of the levees and the capacity of the channels. On the other hand, one of the principal dangers in this system is the neglect of maintenance of the levees and channels through a false sense of security that develops during the ten-or-more-jear average intervals between large floods. The levees that form the channel banks may settle, crack or be holed by burrowing animals during the long periods of only l)artial use. Also, the channel ca])acity may deteriorate through the growth of trees, brush or tule or the deposit of silt by the le.sser floods. The intermittent' wettiaigs from smaller floods encourage channel growths. The usually fertile soil and the favorable moisture conditions on the low land thai Hood channels naturally oeeu])y often produce obstructive growths that occupy considerable ])arts of the waterway areas. The nuiinteiuiiu'e of these channels in coiulition to .safely carry off the infrequently occurring lai-ge floods n'(piires constant attention and very considerable expense. Reservoir system. The second system of Hood coiitroi, tliat which reduces the volume of flood flow by detention of excess water in storage reservoirs, is a recent innovation in (*alifoi-nia. The Los Angeles County Flood Control Dis- trict now has a i|i40.0()0,()()() program under way. This provides for the construction of thirteen reservoirs for flood control purposes on Tios Angeles County streams. The City of Stockton has undertaken the consti-uction of a reservoir on the Calaveras River solely for flood THE CONTROL OF FLOODS BY RESERVOIRS. 19 control purposes. The reservoir system has been adopted in these instances because tlie high property values and close settlement of some of the territory protected permits greater expenditures than have been customary in the past. Tlie high cost of constructing reservoirs for flood control alone and the large size required to reduce floods to harmless amounts limits the usefulness of the reservoir system of protection. To be effective with certainty, liberal reservoir capacity has to be provided and the rules of operation rigidly adhered to so that this s]iace will surely be em])ty at the time needed for detaining flood waters. The system is attractive, however, where the cost is justified, because of tlie shorter traffic cross- ings on the smaller channels needed, the elimination of the bother and expense of maintaining large Avaterways in expectancy of a great flood through years of use to but a small part of their total capacity, and the possiijility of utilizing areas that would otherwise be occupied by flood channels. Combined reservoir and leveed channel system. It was pointed out in the first chapter that there is a physical op]ior- tunity to obtain joint use of the same space in reservoirs for botli con- servation and flood control purposes. It was pointed out also that the present possibility for economical joint use of the same reservoir space will, in general, be limited to a reduction of flood flows to a half or a third of that of a large flood. On many streams in California, leveed channels will be recpiired to carry off even a half or a third the volume of a large flood, although, of course, the size of these channels need not be nearly as large. Therefore, leveed channels will ])robably remain l)art of most of our flood protection systems until either the close settle- ment of the overflow areas warrants the great expense of their com- ])lete elimination, or the demand for additional water supplies forces the constructioii of much greater reservoir capacity than will be required for a good many years at the present rate of growth. Thus, the combination of the reservoir and the leveed channel system of pro- tection will probably be most suitable to conditions on many California streams for some time to come. The suitability of the combined system to the immediate future is fortunate, because often much of the work first constructed under the leveed channel system may be utilized in the combined system to afford an increased degree of protection. Also, the combined system of pro- tection removes the most unsatisfactory features of the leveed channel system. In California, the leveed channels take up much room and form awkward obstacles to traf^c and communication. This public inconvenience rapidly gains importance as territory becomes more thickly populated. The cost of bridges alone over wide channels is a large item of expense and increases greatly as denser population demands more convenient routes of communication. In southern California, whose rapid growth has already brought 20 per cent of available flat lands into incorporated cities and towns, and where their extent is limited, the occupation of large areas by flood channels is a serious impediment to community exi)ansion. Although tlie extent of flat lands is greater in northern California, the area occupied by flood channels is nevertheless a considerable item in the 20 WATER RESOURCES OK OAIjIFORNIA. inventory of lands favorable for intensive human occupation. One of the channels of the flood control project in the Sacramento Valley is as much as three miles in width, and in total all the channels of this project occupy 250 square miles of territory that can be put to only partial use. The channels of the combined system would be of moderate size and capacity. Such channels could be more easily maintained, both because they woiild be smaller in size and because a larger part of their total capacity would be used oftener. The elimination by reservoir control of the excessively high rates of run-ott' that are particularly dangerous by surcharging; the present large channels at very infrequent intervals would add to the safety of occui)ying' adjacent lands. The smaller channels would leave greater areas to be reclaimed and would not con- stitute unduly awkward barriers to traffic and communication under the conditions of the near future. Thus, the coiiibined reservoir and leveed channel .system of protection has distinct advantages. If a satisfactory prog-ram could be devised for the joint use of the same reservoir space for both conservation and flood control, it will come into use on many California stream^s. On those streams wiiere leveed channels are already constructed, the safety of protection would be increased, and on other streams the cost of building the leveed chan- )iels would be reduced. All localities would be benefited. The Sacramento Valley has progressed further than any other sec- tion of California in perfecting- a leveed channel system of flood i^ro- tection. Here a very extensive program is about two-thirds complete. The levees along- the main river channel ai-e constructed to grade and cross-section for i)ractically the entire length and a substantial part of the larg-e by-])asses is already built. The i)rincipal unfinished work lies along- the tributary streams. The conti-ol of floods by reservoii's could not affect the works already constructed except to increase their elBcienc}^ in protecting the reclaimed lands. It would reduce somewhat the volume of unfinished work, but the g:reatest benefit would accrue by the attainment of a higher deg:ree of protection than is afforded by the present system of leveed channels alone whose planned degree of safety is inadequate foi- the intensive development and close settlement of the future. Other benefits would accrue in the reduced project main- tenance and in the greater reclaimed areas and shorter traffic crossings attending- the use of narrower channels than are at i)re.sent jilanned along- the tributary streams. Thus, the combined reservoir and leveed channel system of flood protection Avould have great value even in the Sacramento Valley, where the leveed chaniu'l system is lai-gely completed. Degree of protection in flood control systems. In estimating: the future, while witnessing the present rapid growth of i)opulation and expansion in i)ro])erty values, it would seem that jiublic 7)olicy may recpiire a higher degree of ]n-otection than present economy would dictate in order to ]n'eserve public confidence in the safety of residing and doing business in areas subject to flood hazard. Prom this viewi)oint, the degree of i>rotection rendered by flood control woi-ks becomes an im|)ortant subject, for about a fifth of all the agri- cu1tni-al area in its natural condition is subject to flood menace. THE CONTROL OF FLOODS BY RESERVOIRS. 21 In examining the essential characteristics of the two systems of flood protection, there does not seem to be any inherent difference in the degree of protection afforded by either one. Although there is a danger in transporting large volumes of water above the ground surface between parallel leveees because of the dependence for safety upon the integrity of many miles of earth dike, nevertheless this system could be constructed to offer the same degree of protection that is contained in the reservoir system. The levees would have to be built with heavy cross- section and protected on their face from wave wash and sloughing and the channels would have to be properly maintained. The degree of protection offered by either system or their combina- tion, if sound physical works are constructed with equal safety factors, is essentially dependent upon the possibility of occurrence of floods greater than the capacity for which the system is designed. Under either system, should a flood exceed the design capacity, the channels ■would be surchcirged, with the consequent flooding of the adjacent lands. Inquiry into the possibility of occurrence of floods greater than the design capacity of protective systems, therefore, must be the principal feature of a general discussion of the degree of protection oifered by flood control systems. Frequency of flood occurrence. A discussion of the occurrence of floods in California streams and the probable frequency- with which floods of various sizes might be expected to occur has been presented in the 1923 report* on the water resources of the State. Here it is shown that stream flow closely follows the characteristics of precipitation, the volume of which is the resultant of the vicissitudes of weather so complex that they defy analysis. Precipitation records show that extremely high rates of rainfall are rather infrequent and invariably occur in the winter months only. The record at San Francisco,** centrally located and one of the longest in the State, shows that more than four inches of rain in twenty-four hours occurred but once in the sixty-one years of record, while from three to four inches of rain in twenty-four hours occurred nine times in sixty- one years, from two to three inches twenty-nine times, and from one to two inches one hundred and sixty times. • Thus, it is seen that the highest rates of rainfall occur only at long average intervals of time, while the lower rates occur oftener and with increasing frequency as the rate becomes less. The duration of rainstorms follows a similar behavior. The San Francisco record shows that eight consecutive days of rain averaging more than one inch in twenty-four hours occurred but four times in the sixty-one years of record, while it occurred for four consecutive days twenty-nine times, for three consecutive days fifty-three times, two con- secutive days one hundred and nine times, and one day three hundred and eight times. Since it is the combination of extended storms and high rates of precipitation that furnish flood run-off, the frequency of flood occurrence in the stream channels of California may be expected * Chap. V, Bui. No. 5, "Flow in California Streams," of the Division of Engineer- ing and Irrigation. State Denartment of Public Works. ** U. S. Weather Bureau Record 1897 to 1926. Private Record of John Petee 1865 to 1897. 22 WATKR RESOURCES OF CALIFORNIA. PLATE I. SACRAMENTO RIVER NEAR RED BLUFF I I 1 [III! TT TTTT M , . , ! ■ ' - I , - , • 1:::: ■6- id ? :- __ T M ^ i 1 ! 11 1 1 • "^ . - i\ \ 1 1 _ ^-, i - ■ t T ; - - - : - ^^ ^1^ tn Drainage Are; 9,258 sq.mi. ^T-{ 1 1 tr^ m^ " k^ 1 ' :^H — ■ 1 1^' ood flow in second feet. ^,. -- "^ f i^sJ. 1 , j j -1— L- I-iii 1— 1 1 Util— i i n> ^h.i.i ^ i . 4000 .05 . n i .1 .2 .5 A 5.6.7.8: 1 2 s! 4I M M j 5 67 10 20 1 S0{40l MM so 80100 200 ,300 1 SOO 1^000 2000 MOKEILUMNE RIVER NEAR CLEMENTS 1 1 ' ' 1 1 'i!i j 1 V) .8=-: = wflfN m kM #= i i|i ii| 1 w o yr t ' Dr 1 1 1 '^ ainafe Arei S^2 so. mi. H ^-.44.. ^ffl 5^^ 1 — '■ — i 1 1 ■ 1 — ^ 1 ' jltiplv by 16,994 to get LI M [ , ■ :^ ^' 1 ■iJ" "**^ flood t low in seconfl TeeT. : 1 V il 1 lilE 1 1 1 [ iX :::: ;::o £ jisl n,\\\ 1 .2 J .4 1 l|! ! 5.6.7!8!il MM 2 1 S |4 ilB7 10 M 1 1 1 20 |sol4a| !^ 1 1 i ■ ri 80 go no 200 ; taa | so ^ SAN JOAQUIN RIVER NEAR FRIANT O 5 " [ [ 1 j 1 4-. ' : ; c 1 1 1 C 1 -- — . ! _j^ , "1" 1 ' ' J i 1 ' ■! ■ .8: + m-^fjr 44-T" — £' :;:;;jj^ ^si -txtTM— J-1Lt_ -T-t:r1 : — .-_ ?i i^^' Dr aina^e Area 1531 sq.mi. ultipl> by 43,856 to get -^'1>'N^ \" .^-.. 1 -L 13 - + ' 1 si- 1 flood flow in second feet 1 , 55 ,i... _H ^. 1 1 1 4- np II ^\ "S ^.! 07, .1 .2 .S \a 5.6.7.81 |l : 3I4 5 B!7| 1 10 1 M Ml 20 ho 1 iOl 'eO 80100 ~l i I 11 1 200 |3DD| 1 50 1 1% 1 ' 2000 ma SA^ U4.J. Jii , : r t : : GABR EL RIVER NEA R AZUSA T-^t-f P^|-"J^ •- i " si ♦'1 '--•— -j- :!!;;:^ ■j -- . ,4:: 4::^---- — 1 1 -^ - — +-) ■ z- 'tn - «» <.^ 1 , , 1 ' f i 1 ' 1 III !5f L- 1 1 ] ^IliiS IIJ..I 1 1 •> ^-4- 1 ' ; ' ! \ r ■ 1: 111 .8 ^ •5 3 '11^ ::: = HH - ■ 1 — .5 - : If D ralnage Art a 214 sq.mi. .... _ -^ ^NF 1 ^ 1 II. i/i. Jltiplv by 5754 to ^et t V 1 1 ,2 * L\ 1 1 *^*i flood flow in second Teet. 1 ' ' , ;\kl ; Il 1 ] ■ . X 1 1 .1 :: mi Dti' It™ 1 llllllll <■ ^••tt f Jl . . S .4 frequer .5 6 J 1 icy witf 1 which 5i;7 1) -^ - ;- .-.i.,.,. , ... :„ , ;.g, , , .;.: values are exceeded in 100 _years .... , Wtl Probable Frequency of Flood Discharge THE CONTROL OF FLOODS BY RESERVOIRS. 23 to have characteristics similar to the frequency and dnration of the higher rates of precipitation. An extended comparison of all the stream-gaginp- records in the State* reveals this to be trne. Although this study does not disclose the sequence Avitli which floods of various sizes follow one another, it does indicate that there is a rather fixed relation between the size of floods and the average interval of time between their occurrence. In general, it indicates that, on an average of once in four years, floods may occur double or more the size that is exceeded but once a year ; that on an average of once in twenty years floods may occur three or more times this volume ; that once in two hundred years they may occur over four times this volume ; and at intervals of a few thousand years a flood may be expected surpassing five times the volume that is exceeded on an average but once a year. It thus appears that the largest possible flood may not have occurred on any California stream since white man has resided here, and that the greatest flood yet observed on any of the streams may be exceeded at any time, but only at average intervals that increase in length as the magnitude of the excess is greater. The relation of the size of floods to the average interval of time between their occurrence disclosed by the stream flow records on four typical streams, the Sacramento, the Mokelumne, the San Joaquin and the San Gabriel rivers, is set forth on Plate II, "Probable Frequency of Flood Discharge." For convenience of comparison, the rate of flood run-off is here expressed as inches depth of run-off in twenty-four hours on the tributary drainage area. A multiplying factor is given on each chart to convert the values of depth of run-off on the drainage area into mean rate of run-off for twenty-four hours in second-feet. The horizontal scale expresses the frequency with which values are exceeded in 100 years. The dots plotted on the charts are the floods on the respective streams taken from the records of measured stream flow that have been maintained for the past twenty to thirty years. The actual occurrences counted from the records have been expanded by iiroportion to obtain the probable number that would have occurred had the record been 100 years in length. Double logarithmic scales were used in plotting these charts because of the convenience in shape of the resulting curves. To illustrate the interjiretation of Plate II, reference is made to the upper diagram portraying the probable frequency of flood occurrence on the Sacramento River near Red Bluff. On this diagram the hori- zontal scale represents frequency. The whole figure 1 represents one flood crest in 100 years. One-tenth represents one-tenth of a flood in 100 years or one flood in 1000 years. Similarly 4 represents fonr flood crests in 100 years or one each 25 years. Following up the verti- cal line labeled 4 on the horizontal frequency scale, to intersection with the curve, it will be noted that the A-alue opposite the intersection on the vertical scale of run-off on the left is one. This means that, on an average, four flood crests in 100 years, or one in twenty-five years, will probably exceed one inch in depth of run-off in twenty-four hours on the tributary drainage area. This rate of flood run-off is converted into second-feet by multiplying by the factor 248,937 (shown on the face of the diagram). Thus 249,000 second-feet mean dailv flow mav be * Chap. V. Bui. No. .'>, "Flow in California Streams," of the Division of Engineering and Irrigation, State Department of Public Works. 24 WATER RESOURCES OF CALIFORNIA. exceeded on an average of once in 25 years. For convenience, this value has been referred to in Chapter I as the "once-in-25-year flood." It approximates the flood called "maximum" in the usual engineering parlance of this locality. It may be observed on Plate II that tlie plotted data fairly define curves of regular shape that may be extended beyond the limits of the observations. By so doing, some comprehension may be gained of the frequency with Avhicli floods might occur greater tlian those a})pearing in the comparatively short period of observation. The following table, obtained by scaling the charts, sliows how rarely the excessively large floods occur. It also sIioavs how the size of flood, that may be expected at increasing intervals, grows larger quite rapidlj^ up to those occurring on an average of once in twenty-five years. For longer intervals the size groAvs larger less rapidly. DEPTH OF FLOOD RUN-OFF ON DRAINAGE AREA OF FOUR ILLUSTRATIVE STREAMS IN INCHES PER 24 HOURS. Frequency with which values are exceeded River Ouce a year Once in 10 years Once in 25 years Once in 50 years Once in 100 years Once in 1000 ynars 0.44 0.51 0.40 0.49 0.85 0.89 0.71 2.49 1.00 1.05 0.81 3.34 1.15 1.15 0.89 4.00 1.25 1.25 0.96 4.62 1.65 Mokclumne* 1.61 San Joaquin 1.22 6.74 It is seen that the depth of flood run-off from the drainage areas of tlie three streams north of Teliacha])i Pass is much alike for large floods, except that it is slightly smaller on the San Joaquin River. The depth of flood run-off on the San Gabriel, a typical stream of southern California, is several times as great for large floods as on the northern streams. It shows how much larger floods in pro]iortion to the size of their drainage areas dcvelo]) on the southern streams. The foregoing table of frequency of flood flows on the four illustra- tive streams, in expressing the rate of run-off in inches depth on the drainage area per twenty-four hours, does not show the actual magni- tude of the flood values. The following table expresses the values parallel to the former table in second-feet. These are the estimated quantities at the gaging station on each stream near the edge of the valley floor. ♦Water Supply Paper No. 551 of the United States Geological Survey, recently published, places the maximum discharge of the Mokelumne River at Clements at 25,500 second feet. This is obtained bv applying the rating curve of the 1911 flood to the gage heights of 1907. The crest discharge of the 1907 flood has been pub- lished as 17,000 second feet in former publications including Water Supply Paper No. 299 in which are printed the daily discharges of the 1907 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing this volume. Should the daily discbarges of the 1907 flood be revised by application of the 1907 gage heights to the 1911 rating curve, the increase in their values would be so sub- stantial as to require a complete revision of the analyses of floods on the Mokelumne Hiver contained in this volume in ordei- to make the analyses harmonize with the increased discharge values. THE CONTROL OF FLOODS BY RESERVOIRS. 25 FLOOD RUN-OFF OF THE FOUR ILLUSTRATIVE STREAMS IN SECOND-FEET. Frequency with which values are exceeded River Once a year Once in 10 years Once in 25 years Once in 50 years Once in 100 years Once in 1000 years 109,000 8,700 17,500 2,800 212,000 15,100 31.200 14,300 249,000 17,800 35,600 19,200 286,000 19,500 39,000 23,000 311,000 21,200 42,100 26,600 411,000 27 400 53,500 38 800 It is interesting to note in examining tlie charts of Plate II that, even with the continued extension of these curves to intervals of time thousands of j-ears long, the size of floods still grows larger with the increasing length of the interval. This indicates that there probably is no limit to the size of floods that may occur, but that the very largest ones occur only at intervals of many thousands of years. It would appear, therefore, that absolute protection from floods is impossible and that the degree of protection desired should be carefully considered in laying out protective systems. Because of the unlimited size in wliich floods may occur, flood control embodies an economic ([uestion as to the size for which protective works should be designed. The engineering i)rofession has generally accepted designs based upon the greatest flood of record or upon a more or less arbitrary increase to it resulting from a study of high water marks or the memory of old inhabitants. The foregoing analysis, however, shows that all of these may be exceeded at long intervals of time. The design floods used in the adopted flood control plan ** for the Sacramento Valley, the greatest work in flood control consummated in California, are found to closely approximate the mean dail}^ values that may be exceeded on an average of once in twenty-five years. The design quantities adopted by the California Debris Commission in 1911 were revised in 1925 after further study. Both the original and revised quantities are compared to the once-in-25-year values in the following table : * Water Supply Paper No. 551 of the United States Geological Survey, recently- published, places the maximum discliarge of tlie Mokelumne River at Clements at 25,500 second feet. This is obtained by applying the rating curve of the 1911 flood to the gage heights of 1907. The crest discharge of the 1907 flood has been pub- lished as 17,000 second feet in former publications including Water Supply Paper No. 299 in which are printed the ctaily discharges of the 1907 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing tliis volume. Should the daily discharges of the 1907 flood be revised by application of the 1907 gage heights to the 1911 rating curve, the increase in their values would be so sub- .stantial as to require a complete revision of the analyses of floods on the Mokelumne River contained in this volume in order to make the analyses harmonize with the Increased discharge values. ** Report of California Debris Commission, .Tune 29, 1911, 26 WATER RESOURCES OF CALIFORNIA. COMPARISON OF DESIGN FLOOD FLOW USED BY CALIFORNIA DEBRIS CONLMISSION IN SACRAMENTO VALLEY FLOOD CONTROL PROJECT WITH THE ONCE-IN-25-YEAR VALL'ES OF THE WATER RESOURCES INVESTIGATION. Stream Design flood flows of California Debris Commission in second-feet 1911 Report 1925 Report I Flood flows (av. 24 hrs.) exceeded once in 25 years i Water Resources ■j Investigation I in second-feet Sacramento River near Red Bluff 250.000 Feather River 150.000 Yuba Ri%er ; 110,000 Bear River 30,000 American River 120,000 Stony Creek 1 30.000 Cache Creek 20.000 Putah Creek 25.000 260.000 180,000 120.000 30.000 128.000 30.000 20.000 25.000 249,000 171.000 128.000 29.000 119.000 45.000 20.000 46.000 In the Sacramento Valley the crest discharge of large floods is approximately 10 per cent greater than the average flow for twenty- four lioiirs. Therefore, the crest of the once-in-25-year flood would encroach upon the freeboard of the levees of the Debris Commission plan to the extent of about 10 i)er Cf^iit of the channel capacity. Since this encroachment on the freeboard would be of only a few liours' duration, with usual maintenance, tiie works as planned should protect the project against floods that will not be exceeded on an average oftener than once in twenty-five years. Because of the difficulty in parts of the project, not intensively cultivated, of meeting asse.s.sments for the work from the sale of products of the land, it is believed that this ]U'otection is greater than these lands can now afford. On the other hand, perhaps it is not a sufficient degree of protection for the intensively cultivated sections and the thickly populated areas about the City of Sacramento. It would seem that at least the design flood for the American River, which directly menaces the City of Sacra- mento, should be relatively larger than for other parts of the project. Thus, the degree of protection employed in designing flood control projects should be governed by the class of territory to be protected. Logically, it should be increased from time to time as the territory becomes more thickly populated and property values become larger. The analysis here presented offers a convenient means of expressing the degree of ])rotection of any project in terms of the average interval of time in wliidi the design flood may be expected to be exceeded. THE CONTROL OF FLOODS BY RESERVOIRS. 27 CHAPTER III. THE PRINCIPAL CHARACTERISTICS OF FLOOD OCCURRENCE. Regularity of flood occurrence. It has been pointed out in Chapter II, that the records of stream flow in California disclose a relation between the size of floods and the average frequency of their occurrence. Floods occur in their varying sizes at regular average intervals throughout long periods of time. Although floods happen almost every year, only the smaller ones are at all frequent. Extremely large floods occur at such long average inter- vals that several generations may pass without witnessing one of greatest magnitude. This relation disregards the sequence with which the various sizes follow one another and expresses only the average frequency of their occurrence. A glance at the records is conclusive that the actual sequence is most irregular although the average occurrence seems to follow a regular behavior. The combination of this irregularity in sequence of the various size floods and the long average intervals between the large ones, creates an impression of erratic behavior in flood occurrence that is not indicated by a close analysis of the records. A study of the records shows that a degree of systematic behavior exists sufficient to determine within useful limits certain characteristics as to the time of year and the amount of previous precipitation in the season with which they occur. However, this behavior is not so systematic that the relations may be discussed by directly plotting the quantities on coordinate paper in the usual manner ; rather they must be approached by determining limiting values within which all events occur. The limiting values to these relations found to characterize floods by these investigations, are presented herewith. They concern the time of year, the previous seasonal rainfall, and the seasonal run-off subsequent to flood occurrence. Time of year of flood occurrence. The sharp division of the California year into a wet and dry season is of common knowledge.* Precipitation in any quantity is confined to the six months period from November 1st to May 1st while the remaining six months are for the most part warm and dry. Except in the desert sections of the State and on streams fed by extensive snow fields, floods occur only during the rainy season ; however, the extent to which the flood season varies through the six months in which rains occur, is not generally appreciated. Stream flow records indicate that the time of year in which the largest floods occur is limited to mid- winter and, during the remainder of the six months period of rain, only lesser floods occur in sizes that become smaller toward either extremity of the season until a date is disclosed before and after which floods do not occur. On streams fed by extensive snow fields, floods of • For full exposition see Chap. II, Bui. No. 6, "Irrigation Requirements of Cali- fornia Lands," of Division of Engineering and Irrigation. State Department of Public Works. 28 WATER RESOURCES OF CALIFORNIA. PLATE III. SACRAMENTO RIVER NEAR RED BLUFF 1895-19 25 SEPT. i OCT. NOV. DEC. JAN *>FEB. i MAR. ■ APRIL \ MAY JUNE JULY 1 AUG. j FebZ.iaS Veb.3.1909 « • • • • • *.% . •, • . \' : • .• *. .^ ••.* - • .i* C-V*» •* '.V . • , ¥ •-',. irw*».'«^ ••* •? . 5*. • . .• •»." V*. ..*r^ • • ■ • i <^^v« <^.^\,^. r-'.. % 1 ! i i MOKELUMNE RIVER NEAR CLEMENTS 1904-1925 c o o 3^\'''^' ''' ! • s "•yi ''-,■> i «• |%*-».iv'.>"ir»*fl« I ^ .-^•' . 2 i 1 1 1- ■ 1 0) bX) SAN JOAQUIN RIVER NEAR FRIANT 1907-1925 > L- O .^ -*■ 1 <+- T3 O O SEPT. OCT. NOV. DEC. JAN. • \ FEB. j MAR. APRIL MAY JUNE JULY AUG. 'Jan.31,1911 -4 • • • *. ' 1 ir ' • • , • - • '*''*\'\ • • o ' • « # ^^^^^ 4 ^ • * • • . • %•. ' ••.>«: J ^•irCA*:^./:^-:.. _ ' 1 u_ SAN GABRIEL RIVER NEAR AZUSA 1895-1925 SEPT. OCT. NOV. DEC. JAN. j FEB. MAR. APRIL MAY JUNE JULY AUG. \Jan.l8,l9l6 '* » 1 • 1 • • • 1 • • 1 • 1 • ' • > '^ • •.:,• 1 •rvju !lr»/*i ^SJL wo^. k. •• i Plot of All Floods of Record-Years Superimposed THE CONTROL OF FLOODS BY RESERVOIRS. 29 medium size occur in the early summer after the close of the precipi- tation season. These floods, fed bj^ melting snow, are not as large but are of longer duration than those fed from rainfall. They have their special characteristics. An extended investigation of the time of year of flood occurrence was made on streams having the longest record of measure- ments. In order to avoid a tiresome review of similar data, those of four typical streams only are presented, the Sacramento, Mokelumne, San Joaquin and San Gabriel rivers. These data are displayed on Plate III, ' ' Plot of All Floods of Record — Years Superimposed. ' ' A dot is plotted on this plate for every flood of record both large and small, at the day of its occurrence indicated on the horizontal time scale. The size of each flood in second-feet is shown on the vertical scale. The great preponderance of small floods and the apparent irregu- larity in occurrence of the larger ones may be observed at once by the relative position of the dots. The manner of their clustering also illustrates how the larger floods occur during the midwinter months and how their magnitude decreases towards the fore and latter part of the season. The dots of greatest height on the graphs are in the midwinter months for all four streams. These represent rain-water floods. The dots on the plots for the Mokelumne and San Joaquin rivers forming a distinct cluster in the early summer months, but of lesser height, represent floods resulting from rapidly melting snow on the high mountainous parts of their drainage areas. The Sacramento and San Gabriel drainage areas do not have sufficient precipitation as snow to cause floods during the melting season. Most of the snow that falls on these drainage areas melts in the early spring and augments the run-off from rainfall. It is interesting to note from the manner in which the two groups of dots cluster, that floods from melting snow occur with greater frequency and regularity than those from rainfall but, in general, do not attain much more than half the size of the large mid- winter rain-water floods. The position of the dots, in relation to the time scale of the diagram, indicates dates before and after which floods of much size have not occurred within the 20 to 30 years of record on these streams. These dates vary somewhat on the several streams but, in general, floods resulting from rainfall occur between November 1st and May 1st with the largest ones in the months of January, February and March. The snow-water floods occur between May 1st and August 1st with the greatest ones in the first half of June. Limiting dates to the flood season. While Plate III, "Plot of All Floods of Record— Years Superim- posed," furnishes a perspective of the time of year during which floods of the various sizes occur, a closer analysis is desirable for working purposes. It may be observed on Plate III that the relation betAveen the size of floods and the time of their occurrence is rather broad in its character. There appears, however, to be certain limiting dates for the medium and large floods before and after which the many records of daily run-off disclose neither an instance of nor a tendency toward floods of that size occurring. For a close valuation of these limiting dates, it is not enough to enter the records of occurrence and select the dates 30 WA'lKli RESOURCES OK (AI.II'OkXIA. PLATE IV. SACRAMENTO RIVER NEAR RED BLUFF 1 II S^bol Size 0*" flow cjtceedcd *^'^'^S««^fee. Aufi. I 30 74.700 40 99.fr00 50 I24,5(J0 60 149.400 70 1 174.300 ,llllV June i Mav ,/ j 1 1 1 , 1 , . , 1 ^ " — •. _: ^n^ 1 ^ \ — — - - . -■ . " ■ April r\ "^ ~ - - .. ■ *UT*/' ■ .. ^ kir-^n- ■ ,11 rA-- — ,i ■ - ^ - „r- -:+ ~ % ' } 70 "b^ ""-::'♦. ^t,~ :j "^ ~. . / . ^ >/ j 1 f / i Mar. T •^ ^ 1 ,s. ^ ^j^t-^]Ai> k / / T"'" •^ ^ ^ y i't ^ ' V / ' ' ' Iminatin^rl, . Ffth, ymirngjlalES between which flows in excess ^ ^1^ .f S /T n ^ /J s / ^^\ ^ (St in > r-^^J*-* 1 i expectancy ot i KWS d , .;' J^Jx^J^ \y "V;~-L excess otspecifiea size Jan » ^- y^jy^ y^y 'A" ' ^ '• a-'^i^^^l : - ■^ \ -,0-^^^ -^^0^ y' \' Dec. ,. '0-^ ^-^-"^""^^f- \-^^^ , 1 ' 1 ^~ ■- — ) ■"■ , 1 Where data oftwoor M -^ ^ -- !:5o% (— - •* >■ L 1 1 I more specified sizes ot [ Nov. 1 I 1, ■^ flow 3n» coincident.onjy r "/"^"^ ^ ^. ^ ■"*■ ,.30% n i' ' ^^ --- placed at the side of A Oct -• — ir-d" r ' ' """"'""""'' 1 1 cates the rof J ne«tlo«er LI sept 100 1.000 10,000 SAN GABRIEL RIVER NEAR AZUSA ' ,S-:-orf'o..e.c^ede«| Au^. Symbol »?e°a''r'Ui^«<'"d'«' : 10 1,900 20 3,800 30 5,800 40 7.700 JlllV r 1 50 1 9.600 1 « 60 1 11.500 • 1 70 1 13,400 1 .June _.„.,.. ^TT r~r Mav o ' ' ' V-' 1 1 1 . \ 1 1 H -k i;: 1 1 i 1 'ill , 1 1 1 April '■---t^ - — -*. -: 10°, 1^4. ii_ I j t 1 1 r- -).»- !" 3 - .- ' 1 ! '■i /- / = A--.^ - ^ Z Z.^ i 50"°;." ■^ L *"/?• »/ * / J^ /^ . / Mar, 1 A\,J^ w * I '^/ o' / ..r ~ ^"^ - ^ + J ^^y *7J A^/ [^ t i Feb UmltM.dalss between excess — ^^s «^ f^ -f^(^ Imifiiitinljks of ectancyoffbwsin ESS of specified Size whicntTows ir 1 ^i^n^j^'^^.T* 7" r **' of specified size occur. ^y^j^>^ '^k yc b^ ^ Jan. // 1 ' 1 • -,n»/ >0\^^>^^^ \, ^\ > 1 // I ! ^70%>^-<>rW\,:.^ , i^ / / =p!g ;.^^ •aiear flood THE CONTROL OF FLOODS BY RESERVOIRS. 31 before and after which largo floods have not occurred. In so doing, no conception would be gained of the reliance that could be placed upon their future occurrence within the dates selected. In order to determine as well as may be, the reliance that may be placed on selected limiting dates, the daily stream flow records of twenty streams were analyzed in regard to the frequency with which specified flows were exceeded both prior and subsequent to various dates during the season. The analysis tabulated the occurrences within the period of record so that their frequencj^ could be counted. The frequencies counted from the records of the four illusti*ative streams, are plotted on Plates IV and V, "Relation of Time of Year to Flood Occurrence." Plate IV presents the data for the Sacramento and San Gabriel rivers and Plate V for the Llokelumne and San Joaquin rivers. The rates of flow are expressed in relation to that of a once-in-25-year flood for con- venience of comparison between streams. A conversion table to second feet is given on each diagram. Cross-section paper ruled to logarithmic scale in one direction was used, since it was found by trial that more satisfactory graphs could be obtained by so doing. Smooth curves were drawn approximating the trend of these data and labeled with the rate of flow for which the computations were made. There are two curves in each diagram for the same rate of flow, one full- line and one dotted-line curve. The full-line curve show^s the probable frequency with which the specified flow is exceeded prior to the date indicated on the vertical scale. The dotted-line curve shows the probable frequency with which it is exceeded subsequent to the date indicated on the vertical scale. While it is evident that the data do not disclose exact relationships, it may be noted that the curves representing the smaller flows are fairly well defined. More data are available concerning small flows than large ones for they appear a greater number of times in the records. The short term of the records relative to the infrequent occurrence of large flood flows prevents their containing adequate data for displaying the relations plainly. Were there as many data con- tained in the comparatively short records concerning the larger flows as there are for the smaller ones, it seems probable that their curves would be equally well defined. However, the curves for the larger values take logical positions in relation to available data when drafted by comparison with the data for the smaller flows. The advantage of the analysis delineated on Plates IV and V is that the curves of relationship developed from the data collected during a quarter century, may be extended to indicate expectancies, had the records covered much longer periods of time. For instance, by extend- ing these curves to intersect the 0.1 line on the frequency scale, the time of the year before and after Avhich greater flows than the specified sizes do not occur oftener than one day in a thousand years (0.1 day in 100 years) is indicated on the vertical time scale by the points of inter- section. Intercepts of the full and dotted-line curves on other verticals than the 0.1 line, indicate on the vertical time scale, the period of the 3^ear before and after which the specified flows are exceeded more fre- quently than one day in a thousand years. The frequency with which they are exceeded is .shown by the position of the vertical line inter- sected by the two curves on the horizontal frequency scale. 32 WATER KESOURCES OF CALIFORNIA. PLATE V. MOKELUMNE RIVER NEAR CLEMENTS 1,000 SAN JOAQUIN RIVER NEAR FRIANT 10,000 10 100 1,000 10,000 Number of days in 100 years on which flows are exceeded Relation of Time of Year to Flood Occurrence CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH FLOWS OCCUR IN EXCESS OF SPECIFIED SIZE PRIOR AND SUBSEQUENT TO INDICATED DATES. Flows expressed in per cent of greatest dail^ rate of flow of a once-in-25-^ear flood. THE CONTROL OF FLOODS BY RESERVOIRS. 33 By way of illustration of the interpretation of these plates, reference is made to the upper chart on Plate IV, showing the relation of the time of year to flood occurrence on the Sacramento River near Red Bluff. Selecting the vertical ordinate that passes through the figure 1 on the horizontal frequency scale, it is seen to intersect the full-line curve labeled 50 per cent, opposite November 22d on the vertical time scale to the left. This means that on an average of one day in 100 years there probably will be a flow exceeding 50 per cent of a once-in-25-year flood prior to November 22d. Following the same vertical ordinate to inter- section with the dotted-line curve labeled 50 per cent, it is seen that the intersection is opposite April 12th on the time scale to the left. This means that on an average of one day in 100 years, a flow exceeding 50 per cent of a once-in-25-year flood will probably occur subsequent to April 12th. Thus, November 22d and April 12tli are the limiting dates of the season for floods greater than half the size of the once-in-25-year value with the probability that either limit may not be exceeded oftener on an average than one day in 100 years. The information taken from Plates IV and V is expressed in the following tables. Here are given in the several columns the probable dates before and after which greater flows than the several specified sizes do not occur oftener on the average than one day in a thousand, one day in a hundred, one day in fifty, one da.y in twenty-five and one day in ten years. It is interesting to observe in reviewing these tables, that, of the 365 days in the year, the season for the occurrence of rain- water floods of corresponding size (equal per cent of once-in-25-year flood) opens and closes on the four illustrative streams with the greatest variance in dates of 47 days. It opens from 40 to 72 days earlier for the smaller floods than for the large ones and closes from 20 to 57 days later. For decreasing the probability from one day in 10 years to one day in 1000 years that flows in excess of those specified will not occur either before or after these opening and closing dates, the season opens as much as 65 days earlier and closes as much as 49 days later. The season for the occurrence of floods from rapidly melting snow is seen to be less variable than that for rain-water floods. Of the two illus- trative streams having snow-water floods, the .season for floods of corre- sponding size opens and closes within 14 days of the same dates and these dates do not change more than 23 days for decreasing the prob- ability from one day in 10 years to one day in 1000 years that flows in excess of those specified will not occur either before or after the open- ing or closing dates. 3—52411 34 WATER RESOURCES OF CALIFORNIA. >. J3 ui r-< a> t- t- .-iCOr-l -H '^ >. -o go "g Oa ■^ C« 1 cS 4^ P >"« 100 — --Ol rt S "O >> 1 fc^n rt a o- Og < -t; S S S e ^ 3 e3 S >.| or^t^ 05 05 T3 rt S a i o on T3 ^ eg c t; ti *^ *^ a 0. n^i3 S 0,c O !-• 2 ^ ^ ^ J3 « s C-lrt > J3 ^ ^ CO °.s .§ (M -H to 1- :3 "^o ^H COCl ^ si b^: >; ^ i: « a p, a a ;§ < -^ < < .s ^'i ma>-*ooo ■o >> .-. "o _£3 "3 J3 -2 >•« ^■noo-H-* « s —KM (M o 2 > > 6 6 ^ a . 2 a °.2 S ol 'c iH SqS^ZQQ a ■*j O 1 M 2 is >»2? 05-HN01 ^ ^^ Of-l(M —1 ^ s§ ^ > > 6 6 u . a . 1 >. s 10 t^ r^ ^D-^ £ « >. — 1 C-> -H C-J , o Ii *J ^ > > >" .9 ii -o 00000 C3 00000 l^_CO lO-rt^^CO -sS M* Oi ^ 0> ^ r- c^i •* r^ «- ri; b M s>. ^'b j^ -g-o ^8 !.At3 = 11 **-. ♦-; 00000 ^ S III CO-^iOtOI- .a ^ CO *■ "* >.^ ■^ U^UiCO rt c» -^ -u >, -0 -t3 £2 g 3 3 -2 c« 1 rt •4^ s >>« 00^ ■* ccoo 00 -H— 1 C^ T3 >. c 3 ^^ '-■ "^ « « a a aJ3j2 s 3 •-5 '-3 03 £ m at 1 a >> a 0-<»<0000! (MOO -a 03 3 a 1 -0 >, 0_c 0. a a^i3 >>>. :i:i u< ^ C^ CDOCOCC M.ra Xi ^ >. : ^ i?i:? is .a '■ 2 a a a a * 3 3 >-5l-S is ^ £ S >.g '*05 -^cs -^ 100 3 C3 >> IM.^— 1 CT b^ »^ C C C t- •^-i" (^ a a a a c 1 3 3 0° -<<<<;< >-5>-5 a '~* >, a (>)00-hO 1^0 a <« ^HC> •0 . . ■0 ^ uo § S S c c ° a*^ OS •0 C QQ^^? T3 fe M -2 n1 n 3 5 ^ J3 OS >>! JE rt-oit^o Il- S COtJ" •^ rt S ea — l, c EC 0. rt >»M -«< l^ 00 c "5 W T3 p 03 S (M —100 — (M — bO T3 >> 1^ a 1 0_c lillJ ^ M t^ '■1 >.« oo-^e^ •1 >-HiMe>: « -H J3 tj '** '? Islaa -ts >. a e >. g t- -H oe < a i. -0 ooooo d^ c 00000 00 0^ m^Sit^tt 1° s^ •o't^-'wo'e- if^'h-" ?f c s^ "^ °S s.s« ooooo 00 lis CO-* locor* «•» §fe in a "> THE CONTROL OP FLOODS BY RESERVOIRS. 35 >'« 05 C-> h~ t- 1^ OOOOOlO a> M S —1 CO—I "O >. °l 3 3 3 3 _rt 3 rt -»A E o bS O -l" CJ -H (M — (M'l'-* -*^ C4 flj CO rt (Mrt 'O i~. c !3 ^ ^^J= >■>■>■ a C3* S^ SSSfcfS 3"3'3 3 1-5 >-5 >-5 '-T> IS J3 3 i &§ -rt<0il^-r*0 co-^r^oi T3 g ■a >. ^ CIM C^ -H Cq a £ QJO ^^^c S °.l ^'S 3 3 l-jl-5l-5l-= o K4 C3 2 E '^ 2? 00 ^3 C> 1 §1 "3 "3 "a "3 a 2 •^ OOi 1-H ^ c; o cooo 13 IT ^>> '"'"'"!'"! C^C-5-< M -§ ^ a « M n _>;._>._>>_>;> PH c!2 "33 s'B ►-li-5>-=i-5 c "^ r^ooooi 2 . OOOOOiT-IM O) n IM 5 13 •a ^3 T3 '^ £ J2 3 5 5 >.| i c■.-H,^.^,u, S -f .ra .o uo ^ ^^S'^ _o ?:;z:QQQ ^S2S o- s S « o >.| 03 r^fCiOI' CO CO C-l C-1 'T3 C3 g dr-IC^ -< (M ^c■^ a 'c eg 0_a ^ > > O cj O O O D 0) a. -^ O C3 -a tn ^ >*?. o cocoas ^ CSIMOO-- rt P Oa .-tIM ^H ^ T3 ^ GO ^ > > > a o O O O > ol ^ 1^1 s.a« CO-* lOSt^ OOOQ 1"^ ^fo 1 a; > 2 2 < o z s§ z o z o <3 Q o o b O w Ui H <; Q ^2 CO »0 1- 'r* 'T) IM --I C-l •a >> C3 -o c2 Q. ca ?3 c3-^ -o i^ .« 3 J2 C3 -*^ s O >>« 00 rH CO 05 > c 3 3csi 3 en -2 C3 i >>« rH -^J* O lO OS W to -o a S o "O >, bO 3 1 1 -5? rv Q^ rt c3 cJ c3 rt 5 S 1 M >•! T(< 1- IM 00 CO t^ CJ -d 01 S —1 C^M r-l — ■ J3 OjO '■" '^ '^ fe fe « s J3 So -S'^^SSSS C >3 00 IM CO ^ 00 CO 03 3 ^ >i »-l •-I IM C^ ^ a- '^ ^ g !-■ t: t: 1," t; t? ►; o. a o. o. J2 ,2 — ^•i O5t~-H«J<00 03 S N -< CO —1 O] ■a >. -a °s o S S f^ d ■a J3 "3 ?* Xi 00 CO krt CO CO CO 00 a« ■I —icq mc^ o -a >, ^.1 § g g g d a d o ^QQQ4|,i|^i? Q. 5 '^ o >■! T-H m t- CO to C'l .1 -a ^ C3 S r-IC-) «C-) r-. ■o >, "a o 1 °.a o o S S S D °' O cd o> 2 -a >> coosOQOr- coo —ICO —c^co ■s S§ > J- > 5J o u v O O O £) eu OJ a» '? °.a >> 3 OQ cr H >> s OO OO 1^ «3 -1 CO O 1 ■^o Cq r-IC > > 6 4 6 u O O O 4) 3 © a "^ II ■a a gg gqa S'S 8J — Tco'-Ct^'oi'-reo ^1 fc,-S a rt OS CD i-i a >> "§•3 **^ o-a o 11 a ooooooo . n'l »- t-. C-1 CO •>)> lO CO t^ c3& g C3 o ^ 1 36 WATER RESOURCES OP CALIFORNIA. Date of greatest flood expectancy. Since the analysis of flood occurrence as disclosed by the records of the last quarter century shows definite limiting dates to the flood season before and after which the probability of their occurrence is exceedingly remote, it is reasonable that the flood expectancy should increase toward some culminating date and then decrease as the end of the season is approached. The data i)lotted on Plate III, "Plot of All Floods of Record — Years Superimposed," indicate such culminating dates for the several streams. On Plates IV and V, "Relation of the Time of Year to Flood Occur- rence," pairs of curves are drafted, one dotted and one full-line, each pair representing a flow of a specified size. The dotted curves show the probable frequency with wliich flows greater than specified occur subsequent to the dates indicated on the vertical time scale. The full- line curves show^ in a similar way, the probable frequency of greater flows prior to the date indicated on the time scale. As the two curves of a pair, one dotted and one full-line, approach each other, flows greater than the specified size occur more frequently until the central day of the flood season is reached at their intersection. On this day, flows greater than the specified size occur both before and after with equal frequency. It is the central day of oceurrence for flows greater than the specified size. The dates of the intersection of tlie several pairs of curves on each stream are nearly the same. On the San Gabriel they are within one day of being the same, on the Sacramento three days, on the San Joaquin seven days, and on the INIokelumne nine days. These dates are so nearly alike for the several size flows on each stream that they may be taken as tlie culminating dates of flood expectancy. They vary on the four illustrative .streams from January 20 to February 26 for rain- water floods and, on the two illustrative stream.s having snow-water floods, from May 31 to June 8. Tliese dates are listed in the following table : CULMINATING DATES OF FLOOD EXPECTANCY. Size of flood Date In per cent of gre.itcst dfiilv rate Sacramento River Mokelumne River San Joaquin River of (low of once-in-25-year flood Rain-water floods Snow-water floods Rain-water floods Snow-water floods San Gabriel River 10 Feb. 11 20 Feb. 11 30 40 50 Feb. 8 Feb. 7 Feb. 8 Feb. 10 Feb. 7 Feb. 26 Feb. 23 Feb. 21 Feb. 18 Feb. 17 May 31 June 7 Jan. 27 Jan. 24 Jan. 21 Jan. 20 Jan. 20 June 6 June 7 June 8 June 8 Feb. 10 Feb. 10 Feb. 10 60 Feb. 10 76 Feb. la Preparatory precipitation for flood occurrence. While Ihc records of stream flow show that there is a definite season within whieh floods occur and that the expectancy of floods within tliis season increases toward culmination at some mid-season dale, nevertheless, the expectancy on the .successive days of each season is not THE CONTROL OF FLOODS BY RESERVOIRS. 37 identical in every year. Floods can not occur without preparatory precipitation to wet the earth's surface. If dry, this surface is so absorbent that even the heaviest rains are insufficient to produce large run-off. With the drainage area already saturated from previous pre- cipitation, the same high intensities produce run-off that concentrates in the stream channels to form excessive floods. Sometimes, snow from previous storms, melting in contact with warm rains, augments the run-off from the later storm. For these reasons, the precipitation that has taken place prior to any date in a season markedly influences the expectancy of floods, and, since each season has its own peculiar num- ber, intensity and sequence of storms, the flood expectancy varies on like dates of different seasons. Tliese investigations ha.ve searched for an index of the degree of preparedness of drainage areas necessary for turning off large floods. Since the varying intervals between storms dry up the ground surface to a different extent, the amount of precipitation that precedes floods is variable. An examination of the records shows that large floods have occurred only with very substantial preparatory precipitation. The following table shows the seasonal precipitation at the stations* used in conjunction with the analysis of run-off records, prior to the date of the largest floods on each of the four illustrative streams. The rain- fall is expressed both in inches depth and in per cent of that of a normal season up to the date of the flood. (Season commencing on July 1.) * These are the principal rainfaU stations in the precipitation divisions in which the drainage areas lie. See Chap. 11, Bui. No. 5, "Flow in California Streams." Here the State was divided into twenty-six areas, called "precipitation divisions," in each of which the rainfall at the various stations has approximately like charac- teristics when expressed in relation to its normal although the actual rain in lnche.=! at the several stations may be very different. The rain in Inches at the selected stations Is much less than on the drainage areas for they are all at accessible locations of low elevation. 38 WATER RESOURCES OF CALIFORNIA. ■a § g i a o .igg 131 cgS S .S CJt^ClI^t^Cl->l>OOC|rtt^«5iOTJ<«OOSt~-<».|^-H T3 § o Q <0«-tC»»-t»---.' t^"t^' to" to" to" to' to" o" to" o" Pi c 'o.5g-T3 oiAtAu3-<^-«-«ir« 3 1 03 s a I o lis ill 131 ocqrtC5-*tO'«COt^M"300e<5-a'>COOOOCl->5<«t~-Scno-* — TfOt-i^OMCitoo ■§ o q3 a -Hr^-^oi.*}i».':i--i-* t--" t-" I--' r-.." t^" iV t^" to to" to" c c 3-ll-s ■*tOCJOOU5-*Clt~lO'>»IP5CCN^-HOO(»0>01 oootom>oi«iO'*T(<-*-a-oO'^^ooi^t^ooo^»ccj'<}"^o— its^cit^^^^oooosto C J3 OOlCWM^OimCOCOtO-^ftDOOCO-^C^-HCflOS^M W5OO-^OO^00^-»OQ000»0t^a000tDt^00C0 oo^~e<5rtlo^^c^to■^( O a g« .H-o'3 OOOOOOOOOOOOOOOCSOOOO o^o o o^o_o o o_o^o o^o^o o o o c o o o ..*■" Cs' to* tao" oo !>-" to' O ^ »-<' i^* O* t--' to' -rj-" -H o' 00* CO ci" >o -^ Ci 00 00 r^ 1^ to ic *c •«* -^ CO CO CO CO cc CI CI ca 63"o.S ^-a ||gSSr:p:SSSSSgSI35SSSS5 THE CONTROL OP FLOODS BY RESERVOIRS. 39 o S a ■|S: •S 2 =« 21 2 rt (=1 S T* o cDi-it--«OiC(McDOOOcOOiCOOOCOtCOit^eOOSirQ iOr^»0-^00O(N»-<00C3OC0'*0(M^'-ir-tOi-l ^^T-t Cqi-HC^,-t(M 1-HC^ CCI CM 1-H i-H i-H CO 3-^rfc3rtC-^rtd-5^, oooooooooooooooooooo CiOOOcOCOcD»OOC-?-*0'— icqo^D'-^cot^c<» CDCClCi-HOOOSOOOOCONt-Hb-lOr-li-tl^t^CD'^W eOCOCOCOCOcO-^OOTt^b-iMCOCCCCtM'^iOCO'^CO -ai'-iOO0lOOt-»*O'-t 1— lOii-ti-^C^»-lf-Hai^(MOiT-(C^OsOiiO»Ot>.C<|r-t COTji':Dlr^iCCqcDCO(MiO»Olr-irH'<^i-ia3^HOiOCO '-M CCI i-H CM CC CM 1-H rH(Mi— I 5 '-3 i«=i ^-S << H-s )-5 H 3 )_, 1-3 l_3 1-3 ^ f^ ■s ^ « -a S; o 03 1 03 OOOOOOOOOOOOOOOOOOOO oooooooooooooooooooo fc 0.2 c^-^ li.S t--.ioair^t-^cocic-icDcDocoot--oo»0'--c^aiot^GOcoi-000(300O00^i "o.S g- OSOOOOOiCOCCOOlCCOM^1^H»-IOOiOOCDiC-^ 40 WATER RESOURCES OF CALIFORNIA. The foregoing tables show that the largest floods of record on the four illustrative streams occurred with the per cent of normal rainfall up to the day of the flood, varying from 97 to 156, and the second larg- est floods from 71 to 155. Of the twenty largest floods of record, those on the Sacramento occurred with rainfall varying from 71 to 168 per cent of normal ; those on the Mokelumne, from 76 to 163 per cent of normal ; those on the San Joaquin, from 77 to 167 per cent of normal ; and those on the San Gabriel, from 66 to 263 per cent of normal. There- fore, it is seen that ])recipitation, at least in amount equivalent to a substantial part of that for a normal season, preceded all the large floods of record on the four illustrative streams. In 71 i)er cent of the instances tabulated above, the seasonal precipitation up to the date of the flood was larger than that for a normal season up to the same date. Although it is evident from these figures that the per cent of normal rainfall up to any date in a season is an extremely approximate indica- tion of the degree of preparedness of a drainage area for turning off floods, nevertheless, in conjunction with another element of the analysis, it was found to have a practical value greater than any other index of a simple nature. This other element is the approach, in any part of a season, to the limit of rain-producing capacity of weather sequences. It is a matter of common observation that sunshine, clouds, winds and rain follow one another in various complicated sequences. The state of the weather on any day is known to be the result of pre- ceding atmospheric events over a large territory combining with the seasonal cycles peculiar to each geographic location. IMany actions and reactions liave followed one another in finally producing the resulting weather on any particular day. The intensity and duration of rain storms are a product of these intricate sequences. They are limited in value by the reactions to their occurrence which induce succeeding states of weather other than rain. An inspection of precipitation records is convincing that these reactions are effective in limiting both the intensity and duration of storms, for the large values appear in the records only occasionally, less often as they become larger. A conception of the capacity of weather sequences to produce precipitation in unusual amounts may be gained by comparing the total season's precipitation of the largest years with that of a normal season. If these sequences had unlimited capacity to produce precipitation it would show in correspondingly large departures from normal in the season's rain. The following tabulation of the five seasons of greatest precipitation at the rainfall stations used in conjunction with tlie run-off records of the four illus- trative streams shows only two instances of the seasonal preci])itation exceeding twice tlie normal. Therefore, it would seem reasonable that the approach toward the limit of precipitation producing capacity at any time during the season might be measured approximately by tlio degree of normalcy of the precipitation at that time. Thus, Avhen the precipitation at any time ai)proaches, say, twice that of a normal season up to the same date, it would seem reasonable that there would be small likelihood of additional heavy .storms because of the exceptionally large amount of precipitation that must have already occurred to place the season so far ahead of normal. Such a measure would necessarily lack accuracy during the first few months of the rainy season wliile the value of normal precipitation is a small quantity. Until the season progresses THE CONTROL OF FLOODS BY RESERVOIRS. 41 sufficiently for normal precipitation to date to become a substantial quantity, it is a poor base for comparison because the relative value is considerably affected by small amounts of additional precipitation. For the greater part of the season, however, normal precipitation to date affords a convenient base with which to compare the precipitation of the current season. FIVE SEASONS OF LARGEST PRECIPITATION AT U. S. WEATHER BUREAU STATIONS. Red Bluff, 1877-1921 Electra, 1904-1921 Fresno, 1881-1921 Ciaremont, 1891-1921 ' Precipitation Season | in per cent 1 of normal Season Precipitation in per cent of normal Season Precipitation in per cent of normal Season Precipitation in per cent of normal 1877-78 1889-90 1885-86 1914-15 1905-06 215 169 142 141 140 1906-07 1910-11 1905-06 1908-09 1913-14 156 146 130 119 117 1885-86 1883-84 1894-95 1905-06 1889-90 202 194 152 140 135 1913-14 1906-07 1915-16 1892-93 1894-95 160 136 135 131 127 For convenience, the ratio of the actual precipitation up to any date in a season to the normal amount up to the same date (season com- mencing July 1), has been named the "Progressive Rainfall Index" because its value changes daily as the season progresses. Plate VI, "Progressive Rainfall Index at Time of Flood Flow," displays the values* of this index at the time of every recorded flood on the four illustrative streams. Each dot on the graph represents one flood and shows its greatest 24-hour rate of discharge on the vertical scale and the value of the ' ' progressive rainfall index ' ' on the other. All floods of record are plotted. It may be observed on this plate that, of all the floods of record on these four typical streams, those within the highest quarter on the dis- charge scale occurred with values of the progressive rainfall index lying betw^een 90 and 150 ; those within the third quarter occurred with indices between 70 and 180; those within the second quarter with indices between 50 and 270 ; and those within the lowest quarter on the discharge scale with indices between values of 10 and 567. Thus, it is seen that the great floods do not occur with either small or large values of the progressive rainfall index. On the one hand, the small index values witness lack of preparatory precipitation, while, on the other hand, the large index values witness that the heavy rains for that part of the season have already taken place. Limiting values of progressive rainfall index between which floods occur. Although the progressive rainfall index, by its nature, can be neither an accurate index of conditions on the drainage area nor of the temporary approach in any part of the season to the limit of the rain- * The values of the Index for each stream were computed from the records at the principal rainfall station in the precipitation division in which the drainage area lies. These precipitation divisions are defined by the analysis of precipitation in California contained in Chap. II of Bui. No. 5, "Flow in California Streams." Here the state was divided into twenty-six areas, called "precipitation divisions," in each of which tlie rainfall at the various stations has approximately like charac- istics when expressed in relation to its normal although the actual rain in inches at the several stations may be very different. 42 WATER RESOURCES OF CALIFORNIA. PLATE VI. ' SACRAMENTO RIVER NEAR RED BLUFF 1895-1925 2. , 50 75 100 ,. \ 150 r75 200 225 250 275 300 | 22( Feh.2,i915^ I Teb.3.l909 18 • • t 14 10 , •« • • • '' • I ..•••;••••' 6 % •-• 1 t'f. *-• :, ; .* Rood fiow 45300 secft-x^ -1 Index 567 JX 1 • . '•'. :^..-;->;iv.^*^« % • * Z • • » i .'. *i ^.•^•^VPfJi r . wsi '. v» * * • +- J \ MOKELUMNE RIVER NEAR CLEMENTS 1904-1925 o 2 5 50 75 100 125 150 175 200 225 250 275 300 o 0) 16 14- 12 10 8 6~ 4 Z ,-Jon.' 30,1911 • b CO -o • c: • .^ 3 .• ^x,. » * \ # * • • o r i**' M » • +- , Wn- .'•i :::.• • • 1 buo 2 SAN JOAQUIN RIVER NEAR FRIANT 1907-1925 §1 3E 32 2f 21 2C IE 12 J i 25 50 75 /• 125 150 175 200 225 250 275 300 | tU Jari. 31,1911' 3 o • , • I • ^ • 4- . . <+- • : ' .J -1^ i": ■• 1 • u o . • • M-< ^;;v »• •• . • * o SAN GABRIEL RIVER NEAR AZUSA 1895-1925 22 2 5 50 75 100 125 150 175 200 225 250 275 300 Jar .18,1916-' 18 14 •' 10 • • • 1 6 • • •• • 2 •i • • ' • .' » • • * * • r V *•' «. < ''tjtit»0/C 'mStU » \^ne, \ . » • • Progressive rainfall index Progressive Rainfall Index at Time of Flood Flow ALL FLOODS OF RECORD PLOHED THE CONTROL OF FLOODS BY RESERVOIRS. 43 producing capacity of weather sequences, nevertheless, it was found that there are limiting values with which flows of the various sizes occur and that the probability of their occurrence with values beyond these limits is too remote for practical considerations. To define these limiting values of index for the various size flows, an analysis was made of the frequency with which flows of greater-than-specified sizes have occurred in the past with varying index values. The results of this analysis for the four illustrative streams are drafted on Plates VII, Vlli and IX, "Relation of Progressive Rainfall Index to Flood Occurrence." The construction of these plates, as well as the analyses upon which they are based, is identical to that of Plates IV and V, "Relation of Time of Year to Flood Occurrence," except that values of the progressive rainfall index are substituted for days of the year. On the diagrams of Plates VII, VIII and IX, each pair of curves, one dotted and one full-line, represents a specified rate of flow\ For con- venience in comparison between streams, the rate of flow is expressed in relation to that of a once-in-25-year flood. A conversion table to second- feet is in the upper right corner of each diagram. The full-line curves approximate the trend of the data expressing the probable frequency of flows in excess of their size that occur with smaller values of the pro- gressive rainfall index than indicated on the vertical scale. The dotted- line curves express the probable frequency of flows in excess of their size that occur with greater values of the index than indicated on the vertical scale. As in the diagrams constructed in a corresponding way to determine the limiting dates of the flood season (Plates IV and V), the curves are w^ell defined by the data only for the smaller flows for which more data are contained in the stream flow records. The curves for the larger flows were drafted largely by comparison with the better defined curves for the smaller ones. Although the analysis delineated on Plates VII, VIII, and IX can not be said to be exact because of the limited amount of information relating to the larger floods, an examina- tion of the similar trend of the data on the several streams investigated, is convincing that the results are substantially correct to the extent that the future will repeat the past. By way of illustrating the interpretation of these plates, reference is made to the upper figure on Plate VII which shows the relation of the progressive rainfall index to flood occurrence in the Sacramento River near Red Bluff. Following up the vertical line labeled 1 on the hori- zontal frequency scale to intersection with the pair of 50 per cent curves, it is seen that the intersection with the full-line curve is opposite a value of 58 on the scale of progressive rainfall index to the left. This means that, on one day in 100 years, flows will probably occur in excess of 50 per cent of a once-in-25-year flood with a progressive rain- fall index value smaller than 58. Following the vertical line labeled 1 on the horizontal scale to intersection with the dotted-line curve, it is seen that the intersection lies opposite 188 on the scale of progres- sive rainfall index to the left. This means that, on one day in 100 years, flows will probably occur in excess of 50 per cent of a once-in-25-year flood with a progressive rainfall index value greater than 188. The values 58 and 188 are then the limiting values with which such floods occur with a probability of exceptional behavior of one day in a hun- dred years. 44 WATER RESOURCES OF CALIFORNIA. PLATE vn. 300 SACRAMENTO RIVER NEAR RED BLUFF = 200 £ a> — V5 100 •OJO ~ " 1 /nboi Srje of flow exceeded XofOOMT- Second feel ; 30 40 50 60 70 74.700 99.600 124.500 149.400 174,300 : 1 1 ■ / X . iL / gressive rain 01 rr . ^ = ~ - - . . 1 . - J -l . " ■ ' ^ , r ^'^ - " ^ ;'so% ^ '* . 1 \ - a .. — "^ * (■.?~ ,/ ^ .-\ ::mSJ *. ^ * ^ ^ ?A ^ xTII "^ J ' >^ ■jT- ^ Tf 4r 1 ' / or the occur- jf flows in ex- - --- - Limiting values jf ^ " ; -:.v Y-^/«r ^U ' --- ■ence index between wh flows in excess o specified size ocu ch ' - -T- "'h^ i^ ^■^ ^^ ^ - f -ft^^y '■ri>.^T^ i«^ V Vhere data of hue or no's specified sizes of low are a)incident,onlv tie symbol of the largest s shown A numeral s placed at ttie side of uch symbols which in- icates the number of >mbols of next lower rter represented try it. r y uy<\>^\J^:l <'' ^ — h-+-m ^-^r- ff^ M ^^i^S^ \ ' _\. _ _ 1.70% *50% ^1:30% ^ -■::. ^ "l r ~' ~- — ' — t — " ^ — P-i T 1 £= = "i 1 1 1 \ II ^ -n ' ' ' '>' r 6ressive rainfall Index less than indicated . 1 1 ! i 1 lilll 1 M M M 0.1 100 1,000 10,000 400 SAN GABRIEL RIVER NEAR AZUSA Symbol !tofonce-n- 25-»e3rnood Second feet « 10 40 i8 70 1.900 3,800 5,800 7,700 9,600 11,500 13.400 _ ' ' ' ' ' ' ,' ..! ' ,' ' 300 / - -|- 1— — 1 pJ _ -■ v^ ^ressive rainfall index greater than ndicated •V ' "■ - - , - i^V ^ 10% .. ^ \ " ■ . , • e" ^ , , ( ' " . ^ -^ ■• 4 r — *~ -^ ' 1 ■30% ,:~ ■^^ ~" — . ■* "^ .», ■^^.fc ' ■ -. • ■ ^ ** ^ X X ■" . 1 s, ""_j / i =-; - i»n9' ■** '^ > 1' i / J 200 •■ ^ . 1 Tn A ', ■ / H — ** ■* -I >. J "? ^W— 4 _L^ ^(!2t.['di2[al2le..ia ilje — -70% N ■^ V3^ rn T^ -'-'-^ prt)|ressive raintal 1 -■ Limiting values X C "^ v/ Lv_ A f flows in ex- speafied size ot > ' / v\ ^\ /> , 0< ' xnce c £ progressive ram index between wh flows in excess Specified ^ize 00 all ■♦■ ', ^5 ' j\* ¥< / * /\ //^ — — L — 1 Icess of Irh ^f jL ^t Uf 7^ '. ■ ' / of i tT s/^^>f* \5^ .. ^ . ^ vf j^ V y^ /\ V . / 100 /* 'N x( y''^'^ *v^ • » /^ ^^ ' » Where data of two or L 1 .-^^ ^ y !> •^v J^ ' J^ \ / + 70% ^ -^^ "v •^'^^^ ^rf*! >^^ flow are coincident.only [ / E^:: *50S li^fS ^pV^jf^ vixT t V \ the symbol of the largest [ r:3J-l-rr«! J-l ""J^ "^^V I \ f • \ IS shown. A numeral fl =/ — ^ r: 10% ^X S=' ! -V - U * is placed at the side of such symbols which in- i — 1 Flow s nmp.ti ^pH lA/it 1 vail IP 1 — T dicates the number of Svmbols of next lower order represented by it. 1 ■■ 1 1 1 ^ - "Y ', 1 1 1 1 III 0.1 100 1,000 10.000 Number of days in 100 years on whicii flows are exceeded Relation of Progressive Rainfall Index to Flood Occurrence CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH FLOWS OCCUR IN EXCESS OF SPECIFIED SIZE WITH VALUES OF PROGRESSIVE RAINFALL INDEX GREATER AND LESS THAN INDICATED. ^ Flows expressed in percent of greatest daily rate of flow of once-in-25-^ear flood THE CONTROL OF FLOODS BY RESERVOIRS. 45 PLATE VIII. Progressive rainfall index Progressive rainfall index oooo oooo 3 o o o o qO oooo MOKELUMNE river near CLEMENTS Symbol d t r 3 ] 3 3 - %0fOOM-il> Second fee I 30 11 60 70 5.30 7,10 8,90 10, 70 12,50 1 1 1 1 1 i 1 1 1 1 1 1 : 1 •/ /here data of two or lore specified siies of ow are coincident, onl> lesjmbol oflhelarges' shown. A numeral placed at the side of jch symbols whicti in cates the number of ymbols of next lower rder represented b^ it Rain water flow sometimes exceeded vyith vak of progressive rainfall index greater than indicate f t / je :::_/ 1 il i< r ™ ~ " - . . ^ / s W — ■■■30^ • ^'c \ 1- .. — ^ s \ — - ■ ^ ~ * *. ' , I ™\ " ■ — ^ n ' 50 '/c ' *. "* ^ 1 / V — Jt ,. ^ ^ ^ " • 1 ■^ i ° 1 ■j r; - ~" «<. ^ ^ *. V«s r ^ / ^ } J ' •^ J / , J jmitin* value e rainfall inc . of progress- ex between ~)^ - A • J •s •J •> ^^ A '• » ^ *^ t f^ / "^ \t\ ♦\_. ^?'l k / ^ \> t' -^ i^ the occurrence of 1 water flows in ex /hich rain water flows in ex- ' . '; > r* 'fjOf^rn ^' . *^^ ^l -^____^ ^ ' .v% (^ 1 — cess ot specified size i 1 1 70°-.r , ' r" • ■' \^ ^ ' >^ ■*■ o\ y / _ .--^ ^ Y ^ :^5o^ii::i £ 30 % r — *^-' ■ „.rfj^ "* 1 r • 1_ T , \ 1 — ' '- \ ^p • _f - ri i- J J . L 1 of progressive rainfall index less th^n indicat ^s ed. 1 II Mill 1 1 M 1 ml i Mil .1 1 10 100 1,000 10.000 t 0" Second fee jjjearfioa 30 40 5,30 7,10 V ^here data of two or ore specified sizes of ow are coincident . onl^ ie symbol of Ihelarges shown A numera placed at the side of ucti symbols which in- cates the number of ymbols of next lower rder represented by it f t 1' l« s d s /Snowwater flow sometimes exceeded with va! of progressive rainfall Index ^ngater th^ indicate d 1 1 r — - _ . ^u. ■30% •A\- ■■ ■ 40% ~^ " « « . , , ' "^ " ■•-s." • > • " t, ' i ve ramtal! index between which snow water flows in ex- ess of specified size occur. ^ ^ ,/ ■■k / ^ >> the occurrence of 3w water flows in ex .>< *2 —-___ «> ''«~^ r^ ^< " 50 //- ^' 40%^ _^ Icess ot spea tied size --■ "^0% ;■:- —^ ^^ ~T 1 ;; ' ' X ^Snow water flow sometimes exceeded with valu of progressive rainfall index less than indicat 1 1 II 1 1 1 1 1 I 1 1 1 1 1 1 1 1 1 II 1 1 1 1 1 1 1 1 J III 1 1 j 1 1 I 1 11 .1 1 - 10 100 1,000 10 Number of rial's in 100 ^ears on which flows are exceeded 000 Relation of Progressive Rainfall Index to Flood Occurrence CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH FLOWS OCCUR IN EXCESS OF SPECIFIED SHE WITH VALUES OF PROGRESSIVE RAINFALL INDEX GREATER AND LESS THAN INDICATED. riows expressed m percent of greatest daily rate of flow of once-in-25->ear flood 46 WATER RESOURCES OF CALIFORNIA. PLATE IX, 400 SAN JOAQUIN RIVER NEAR FRIANT 1 U -- .-1 1 :. 1 '1 r ' i Symbol M 11 1 1 1 1 : Stofonccrv Second feel V 30 «0 50 60 70 10,700 14.200 17.800 21.400 24.900 1 II 1 i 1 ' ill 300 1 1 1 1 1 1 1 Where data of two or . 1 II ^ 1 -III flow are coincident.ooly ■ innitin^ values ot progress- ive rainfall inde» beiween thesymWofttieiaowii IS Shown. A numeral 1 which rainwater floivs in ex- cess of specified size occur. i« placed at the side of [ xh symbols which in-r a .^Rs.n. water flow sometimes exceeded with valu< flicates the number of -//- 1 'Mil ■\ ^mbols of next lower f ^ order represented by it. | 200 1 1 ' 1 i 1 1 1 1 p* § — — — — •• :.afl7ot-_^ i 1 / I ^1-^= H ^1 .,.L| / 7M ' / ' — i- i 70Ti "Ty ^:r^.?: n— ~h / 1 'III ' ■'C ?5?7 '// Most favorable value of I L || 1 Mill "*■ , *" "^z^"^ ^y ' ■ / X "■ ">«X b^"^'^' ft7 he occurrence of- -' ' fW^ •^ 1 1 ^ J>\J0^ cess of specified size" 100 ' ^ 7;^>CyrV^ ^s^^g^-iwV — 1 ^.7_— i-^-^-^ ^^^.i ,.- r^^ — — ^30^ ■ — "^ _.->'^ '^ - M. -L_ I «• i/- ' ! 1 H ' 1 1 ! Li j__J 1 1 ii !| • } ^"^ ■~-f lain water flow sometimes exceeded with values 1 T 1 i ' ■ ) i n < 1 1 1 1 1 1 1 IMII 1 1 M 1 nil I 1 M 1 1 1 1 0.1 100 1,000 10,000 400 300 c "to L- 200 •oO o Q. 100 -h ' Size of flow erceededl Symbol Xof once-n-j arfto) jecondfeet Tiyt 30 60 10.700 14,200 17.800 21,400 1 i I 1 1 i 1 1 1 Where data oFhxo orjj more Specified Sizes off! flow are coincident, on Ijr n thes/mbdoflhelaniesft] IS she wn. A numeral n IS placed at the side cfn such symbols which rvQ % Limiting values of oroSress- \e rainfall index between ivhich snowwter flows in exr cess of specified size occur. diCdte s the number ot M ■ symb< )ls of next lower n t^ 1 J ' - L. ' 1 . 1 '_L]i 1 1 , of pro^essive rainfall index j^csater Ih^n ir>dicated j30%_^ 1 II 1 1 1 1 -. - - 4w ■H — ^ 1 1 f / n ■ ■ -ii, -i-.hWi rt - ^^ rr=T5 ■■L / 1 1 -Ih ]__ ; n- 6(J% - - -'-J^'- - .r-'^t'i^-.-^^w--' '"^y^ . : : . /T'iv-^- ■'■- ■■- . - ■' 1 -//= — |— j- 1 . .^ . - j><-,-Z>^ r t • // ' i i ! ! ' *.60°o-^^ "T:-.. «;^ fb«s m ex- 1 / specified sizej "1 •TT'" L^i : — -^r : , ;", I '-^ — i-^i-T— ^T-.- .. ,. 1 1 -^^ 1 i 1 1 ' i 1 1 1 1 ' ' 1 1 : 1 ! i.i.i 1 . -.., ■Snow water flow sometimes exceeded with values of oroiressive rainfall index less than indicat< ' ' — - — - ■d — — — — ~ 1 ill MM Mill 1 1 1 1 II IT~"~ — — 1 III 1 1 h lllll 1 1 1 1 II 1 I 10 100 1,000 10.000 Number of da^^s in 100 years on which flows are exceeded Relation of Progressive Rainfall Index to Flood Occurrence CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH FLOWS OCCUR IN EXCESS OF SPECIFIED SIZE WITH VALUES OF PROGRESSIVE RAINFALL INDEX GREATER AND LESS THAN INDICATED. Flows expressed in per cent of greatest daily rate of flow of once- m- 25 -year flooa THE CONTROL OF FLOODS BY RESERVOIRS. 47 The data from which these curves (Plates VII, VIII and IX) were constructed are largely included within frequencies greater than four days in a hundred years. The frequency of four days in a hundred years represents one occurrence during the period of 25 years of measurement, the length of the longer records. Knowledge of expec- tancies had records been kept for greater lengths of time, may be obtained by extending these curves into the zones of smaller frequencies. In so doing, information is gained of the probability of flood occurrence with indices greater or less than the limiting values shown in the records themselves. The limiting values betM^een which any specific flow occurs are indicated on the diagrams by the extremities of the intercept on any vertical line made by the two curves of the pair representing that specific flow. The limiting values of the index are read on the index scale to the left, opposite the extremities of the intercept. The frequency of greater flows occurring with larger or smaller values of the index than there indicated, is read on the horizontal frequency scale where it is cut by the vertical intercepted by the pair of curves. The intercept on the vertical at the extreme left of the diagrams, labeled 0.1 on the frequency scale, gives the limiting values of indices with which flows greater than specified will probably occur either with an index greater than the upper limit or with an index smaller than the lower limit except on one day in a thousand years. The intercepts on verticals represent- ing greater frequencies of exceptional behavior become smaller as the frequencies become larger. These smaller intercepts indicate a lesser range of index values with which flows occur greater than specified. The following tables set forth the range of index values indicated by Plates VII, VIII and IX, within which floods greater than various specific sizes will probably occur on the four illustrative streams. The maximum and minimum values are tabulated for several different fre- quencies of exceptional occurrence. It may be observed, on reviewing these tables, that the smallest limit- ing value of the progressive rainfall index therein is 28 and the largest is 293, both for the San Gabriel River. The extreme values for the other streams are 51 and 239 on the Mokelumne, 43 and 211 on the Sac- ramento, and 46 and 189 on the San Joaquin River. The least values Avith which rain-water floods of corresponding size (equal per cent of once-in-25-year flood) occur, differ not more than 33 points on the four illustrative streams while the maximum values differ not more than 75 points. The smallest floods tabulated occur with minimum indices from 15 to 66 points smaller than the minimum indices for the largest floods and with maximum indices from 14 to 115 points larger than the maximum indices for the largest floods. For decreasing the probability from one day in 10 years to one day in 1000 years that flows in excess of those specified will not occur with either smaller or larger values of the index than indicated, the minimum value of the index may be reduced as much as 58 points and the maximum value increased as much as 87 points. The range of index values with which floods occur from rapidly melting snow is seen to be less variable than for rain-water floods. Of the two illustrative streams having snow-water floods, the smallest value of the index with which they occur is 61 and the largest is 163. The minimum values on the two streams differ not more than 16 points and the maximum not more than 15 points. 48 WATER RESOURCES OF CALIFORNIA. SACRAMENTO RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX BETWEEN WHICH FLOODS OCCUR. Size of flood near Red Bluff- greatest daily rate of flow Minimum index values Maximum index values Frequency with which flows occur with progressive rainfall index* less than Frequency with which flows occur with progressive rainfall index* greater than values tabulated values tabulated In per In cent of 1 1 once-m- second- One day One day One day One day One day One day One day One day ■ One day | One day 25-year feet, in 1000 in 100 in 50 in 25 in 10 in 1000 in 100 in 50 in 25 in 10 flood years years years | years years years years years ; years years 30 74,700 43 48 52 57 64 211 203 198 192 183 40 99,600 47 53 57 62 71 204 196 191 185 173 50 124,500 1 51 58 62 69 80 198 188 182 174 160 60 149,400 55 63 69 77 91 192 179 171 161 143 70 174,300 58 69 76 86 103 187 169 160 148 125 •At Red Bluff rainfall station. MOKELUMNE RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX BETWEEN WHICH FLOODS OCCUR. Size of flood near Clements — greatest daily rate of flow In per cent of once-in- 25-year flood Id second- feet Minimum index values Maximum index values Frequency with which flows occur with progressive rainfall index* less than values tabulated Frequency with which flows occur with progressive rainfall index* greater than values tabulated One day One day One day in 1000 in 100 in 50 years years years 51 56 59 57 65 69 63 72 78 69 80 88 75 90 100 68 71 72 84 87 89 One day in 25 One day in 10 One dav in 1000 years years years One day One day One day in 100 in 50 in 25 years years years 227 221 214 212 205 197 197 190 180 184 176 165 169 160 147 162 161 160 153 112 150 One day in 10 years 30 40 50 60 70 30 40 Raln-Water Floods. 5,300 7,100 8,900 10.700 12,500 5,300 7,100 64 75 85 97 112 71 239 84 225 98 211 113 199 187 Snow-Watcr Floods. 163 154 202 183 164 146 158 146 *At Elcctra ramfall station. THE CONTROL OP FLOODS BY RESERVOIRS. 49 SAN JOAQUIN RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX BETWEEN WHICH FLOODS OCCUR. Size of flood near Friant— Minimum index values Maximum index values greatest daily rate of flow Frequency with which flows occur with progressive rainfall index* less than values tabulated Frequency with which flows occur with progressive rainfall index* greater than values tabulated In per In sejond- feet cent of once-in- 25-year One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 flood years years years years years years years years years years Rain-Water Floods. 30 40 50 60 70 10.700 14,200 17,800 21,400 24,900 415 54 Gl 67 72 53 61 68 75 81 58 66 73 80 87 63 72 79 87 96 73 83 93 103 117 189 185 181 178 175 185 180 176 172 108 182 177 173 168 162 178 173 167 161 153 170 162 154 144 133 Snow-Water Floods. 30 40 50 60 10,700 14,200 17,800 21,400 61 70 78 85 63 72 81 89 64 73 83 92 66 75 85 90 69 79 90 105 149 142 137 133 147 139 133 128 146 138 132 126 145 136 130 123 143 134 126 116 *At Fresno rainfall station. SAN GABRIEL RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX BETWEEN WHICH FLOODS OCCUR. Size of flood near Minimum index values Maximum index values Azusa — greatest daily rate of flow Freq lencv with which flows occur with Freq uency with which flows occur with progressive rainfall index* less than values tabulated lirogressive rainfall index* greater values tabulated than In per In cent cf once-in- second- One day One day One day One day One day One day One day One day One day One day 25-year feet in 1000 in 100 mSO in 25 in 10 in 1000 in 100 in 50 in 25 in 10 flood years years years years years years years years years years 10 1,900 28 35 39 45 55 293 280 274 266 253 20 3,800 36 43 48 53 64 278 261 2,53 242 222 30 5,800 43 50 56 63 77 264 246 235 222 198 40 7,700 49 57 62 72 93 251 231 219 204 177 50 9,600 55 63 71 83 113 240 217 203 186 153 60 11,500 59 69 78 95 229 202 188 169 70 13,400 64 75 86 111 220 188 172 151 *At Claremont rainfall station. Most favorable value of progressive rainfall index for flood occurrence. It has been observed that there are limiting values of the progressive rainfall index with which floods occur. Plates VII, VIII and IX, "Relation of Progressive Rainfall Index to Flood Occurrence," deline- ate the frequency of the exceptional occurrence of flows outside of either of these limits. Pairs of curves are drafted on these plates, one dotted and one full-line, representing this exce])tional behavior of flows exceed- ing specified amounts. The full-line curves show the probable fretiuency 4—52411 50 WATER RESOURCES OF CALIFORNIA. of occurrence of greater-thaii-specified flows with index values smaller than indicated, while the dotted-line curves show the probable frequency of occurrence with index values larger than indicated on the vertical scale. The two curves of eacli pair approach each other as these fre- (piencies increase, until their intersection indicates a value of the pro- gressive rainfall index witli which greater-tlian-specified flows occur equally frecpient with either smaller or larger values of the index. This is the index value with which flows greater than specified occur most frequently since the frequency of occurrence with either smaller or hirger values is the same. Therefore, the values of the progressive rain- fall index indicated by the intersections of these pairs of curves, are the most favorable values for flood occurrence. The following table contains tlie most favorable index values for the occurrence of flows of greater-than-si)ecified sizes on the Sacramento, Mokelumne, San Joaquin and San Gabriel rivers as taken from Plates VII, VIII and IX. It may be noted that the values range from 114 to ]43 for rain-water floods, being least for the Sacramento River and largest for the San Gabriel. On the San Joaquin River the values for the several sizes vary only one ])oint while on the ^lokelumne the \ariance is two, on the Sacramento four and on tlie San Gabriel twelve ))oints. The most favorable values for snow-Avater flows on the ]\Ioke- lumne and San Joaquin rivers, are smaller than for rain-water flows. On the Mokelumne tliis value is 118, while on the San Joariuin it is 110-111. MOST FAVORABLE VALUE OF PROGRESSIVE RAINFALL INDEX FOR FLOOD OCCURRENCE. Size of flood Sacramento River Mokelumne River San .Joaquin River III per cent of greatest daily rate of flow of once-in-25-ycar flood Rain-water floods Snow-water Hoods Rain-water floods Snow-water floods San Gabriel River 10 143 20 136 30 40 50 iis 117 117 114 114 127 128 129 129 129 118 118 124 124 124 124 12.5 no 110 no 111 137 134 134 60 134 70 133 Relation of flood occurrence to season's run-off. It has been i)ointed out througli analyses of .stream flow records, that the mo.st favorable time for flood occurrence, excei)t from melting snow, is in mid-winter. Thus, it would be exi)ected that the largest and heaviest floods occur during the middle of the rainy season followed by a considerable part of the season's total i)r('cipitation and hence a considerable part of the season's run-off. Therefore, since large floods usually occur in seasons of greater than normal run-oft', tlie stream flow subsequent to them should be a substantial fraction of that for a normal .season. The following table presents the nin-olf in the Sacramento, Mokelumne, San Joa(piin and San Gabriel rivers sub.sequent to the THE CONTROIi OF FLOODS BY RESERVOIRS. 51 largest floods on record. The run-oft' is expressed in per cent of the total run-off for an average season. It may be noted that the run-off subsequent to the largest floods of record on the Sacramento River averaged 80 per cent of the total for a normal season, on the Mokelumne and San Joaquin, following rain-water floods, 106 and 120 i)er cent, respectively, and on the San Gabriel 129 i)er cent of the total run-off of a normal season. The run-off subsequent to the largest snow-water Hoods on the Mokelumne and San Joaquin rivers was 44 and 48 per cent, respectively, of the total for a normal season. These values varied considerably with the diff'erent floods. On the Sacramento, INIokelumne and San Joaquin rivers the minimums were about half the average values, but on the San Gabriel it was about a third of the average. It is seen that, for the most ]^art, a very substantial amount of run-off' follows large floods, even the snow-water floods tliat occur late in the season. I 52 WATER RESOURCES OF CALIFORNIA. RUN-OFF SUBSEQUENT TO LARGEST FLOODS OF RECORD. Sacramento River Moicelumne River Rain-water flood Snow-water floods Mean Subsequent daily flow in second- feet Date of flood run-off in I)er cent Mean daily Subsequent run-off in Mean daily Subsequent run-off in flow in Date of flood per cent flow in Date of flood per cent second- of mean second- of mean feet seasonal- feet seasonal' 254,000 Feb. 3, 1909 79.9 16,700 Jan. 30, 1911 •149.1 8.740 June 12, 1906 •50.9 249,000 Feb. 2, 1915 93.1 15,310 Mar. 19, 1907 136.9 8,030 Juno 18, 1911 27.4 196.000 Mar. 20 1907 63.3 11,100 Jan. 26, 1914 101.3 7,970 June 3, 1922 •30,8 188,000 Jan. 16 1909 114.7 10,400 Jan. 14, 1909 •118.3 7,900 June 12, 1911 36.5 188.000 Feb. 10, 1904 121.7 9,850 Feb. 21, 1914 90.3 7,880 June 0. 1911 45.2 177,000 Jan. 21, 1909 101.5 9,700 Feb. 0, 1925 80.8 7,770 May 31, 1922 37.5 176,000 Feb. 25, 1917 44.9 9,250 Jan. 1, 1914 114.6 7,750 June 1, 1915 30.3 100,000 Feb. 21, 1914 05.4 8,400 ,Ian. 21, 1909 110.9 7,670 May 18, 1922 53.9 1.51,000 .Jan. 1, 1914 *113.1 8,040 Mar. 20, 1916 79.5 7,600 June 16, 1906 •45.0 1. 5 1,000 Feb. 24, 1902 x,58.4 7,860 Feb. 2, 1907 107.2 7,550 June 10, 1917 24.0 147,000 Mar. 8, 1904 91.3 7,750 Mar. 31, 1906 119.0 7,500 May 24, 1911 •58.3 140,000 Feb. 10, 1902 X80.9 7,610 Mar. 23, 1907 *127.0 7,480 July 4, 1906 22.4 137,000 Mar. ;?1, 1906 50.0 7,47,0 Jan. 22 1914 100.8 0,960 June 22, 1906 37.6 136,000 Jan. 19, 1906 93.5 7,350 .Jan. 18, 1921 85.1 6,900 June 2, 1907 57.6 134,000 Feb. 4, 1907 99.5 7,210 Mar. 7, 1911 '126.9 0,850 June 20, 1906 40.6 131,000 Jan. 25, 1903 63.6 7,200 Nov. 21 1909 97.4 6,800 June 2, 1909 32.6 130,000 Mar. 7, 1911 50.6 7,060 Feb. 11 1919 .57.8 6,7,50 May 7, 1906 92.4 128.000 Jan. 27, 1896 77.7 6,960 Jan. 19 1906 143.9 6,700 June 8, 1915 X19.2 123,000 Mar. 8 1900 .34.6 6.940 Mar. 12 1918 .50.1 6,640 May 9, 1906 x89.5 122,000 Jan. 22 1914 89.6 6,910 Apr. 16 1925 *51.8 0,6.30 May 13, 1915 48.7 Average va lie 79.6 105.8 44.0 San Joaquin River San Gabrit 1 River Rain-water floods Snow-water flood s Mean Subsequent Mean daily flow in Date of flood Subsequent run-off in percent Mean daily flow in Date of flood Subsequent run-off in per cent daily flow in second- fee t Date of flood run-off in per cent of mean second- of mean second- of mean feet seasonal" feet seasonal' 38,800 Jan. 31, 1911 157.5 23,100 June 13 1911 63.9 22,300 Jan. 18, 1910 125.3 27,900 Dec. 31, 1909 84.0 22,800 June 4 1909 •51.0 16,000 Dec. 19, 1921 253.6 26,800 .Jan. 14, 1909 •132.4 21,500 June 10 1911 *,50.0 12,.500 Jan. 1, 1910 60.0 26,800 Dec. 10, 1909 91.2 19,,500 July 7 1911 27.8 11,800 Feb. 20. 1914 119.9 24,700 Jan. 26, 1914 120.7 16,700 June 5, 1922 45.9 11,130 Mar. 12, 1905 70.7 18,900 .Jan. 21, 1909 •127.5 16,200 May 22 1911 •90.1 9,430 Mar. 20, 1906 83.4 18,800 Mar. 8, 1911 142.9 16,200 June 6 1911 75.8 9,160 Mar. 10, 1911 86.5 13,000 Mar. 10, 1911 •140.2 16,200 May 8 190<.» "80.5 9,150 Jan. 20. 1914 165.2 12, .500 Feb. 12, 1909 •119.9 15,700 June 2 1914 55.1 8,200 Feb. 9, 1922 135.6 11,700 Feb. 21. 1917 82.1 15,300 June 5 1912 19.4 8,020 Mar. 12 1906 •127.4 11,000 Apr. 6, 1911 126.2 14,900 June 15 1909 •35.4 7,940 Jan. 27, 1916 96.7 11,000 Jan. 18, 1910 126,7 14,700 June 27 1911 •39.2 7,100 Feb. 7, 1909 88.6 11,000 Mar. 21, 1916 104.0 14,700 May 31, 1922 54.9 6,810 Mar. 5, 1907 142.5 10,900 Oct. 2, 1918 02.5 14,000 June 24 1909 •20.1 5,920 Apr. 1, 1903 41.1 10,700 Jan. 2.5, 1911 105.8 14,000 June 11 1909 42.1 5,900 Dee. 27, 192! 208.2 10,400 Apr. 5, 1914 103.1 13,800 June 9, 1915 •30.9 5,260 Jan. 29. 1911 164.8 9,910 Feb. 21, 1914 119.0 13,500 June 1, 1915 x44.5 ,5,110 Jan. 18, 1914 187.8 9,150 Mar. 5, 1916 112.8 13,400 June 10, 1917 34.2 5,030 Mar. 11, 1918 58.0 8.900 Jan. 18, 1914 132.2 13,400 May 25, 1922 62.2 4,670 Jan. 10, 1907 214.1 8,720 Mar. 4, 1911 146.0 120.2 13,300 July 18 1911 15.2 47.8 4,220 Jan. 31, 1911 156.8 129.3 ' Mean seasonal run-olT of Sacramento IViver near Red Bluff (50 yr. mean) 9,929,000 acre-feet. " .Mean seasonal run-olT of Mokelunuie Hiver near Olcnients (50 yr. mean) 898.000 acre-feet. » Mean seasonal run-olT of .'-!;in .loiuiuin Hiver near Friant (50 yr. mean^ 2.057,000 aere-fect. * Mean seasonal run-off of San Cial)riel Hiver near Azusa (50 yr. mean) 147,(K)(I acre-feef . •Second day after flood to October 1. xThird day after flood to October 1. All other values of run-off Hulweiiuent to flood are from first day after flood to October 1 . THE CONTROL OF FLOODS BY RESERVOIRS. 53 CHAPTER IV. RESERVOIR SPACE REQUIRED TO DETAIN EXCESS FLOOD FLOWS. Source of infortnation. Of all information t'oncei-ning Hoods, that most imi)ortant to their control by reservoirs is the volume of water contained in the excessive rates of tlow. This is the volume that must be detained in reservoirs if the downstream flow is to be limited to reasonable rates. Informa- tion concernino- the volume tliat must be so detained is contained in the records of stream measurement. Althoug'h the i)eriod of measure- ment in California is too brief for direct disclosure of either the largest floods that may occur or the length of the intervals between them, nevertheless, within these records is the sum total of accurate knowledge of the volume of flood flow. Other information, at best, is indirect and very approximate. Flood estimates based on high-water marks, on the memory of old inhabitants or rates of rainfall that have occurred in other localities, contain many elements of uncertainty. The stream-flow measurements themselves are the only direct and definite information on the volume of flood flow. This study, therefore, is confined to their analj^sis. Continuous stream measurement in California was started with the establishment of the first gaging station at Jelly's Ferry on the Sacra- mento River in 1895. Since then many other stations have been estab- lished on the larger streams. At present, about 250 stations are main- tained by the United States Geological Survey and the State of Cali- fornia in cooperation. From the continuous records kept at these stations, the United States Geological Survey publishes in its water- supply papers, tables of the average daily stream flow past each one of these points of measurement. The published tables, together with those in preparation for publication, have been used in the computations of this bulletin. Method of analysis. Since the stream-flow records cover too short a time to include the maximum flood that might occur, it is desirable to ascertain the rela- tion between the volume of flow and frequency of its occurrence as disclosed by the many smaller floods observed during the period of record. To ascertain the volume of water contained in the excessive rates of flood flow, the records on twenty streams of the State that have been measured from seventeen to thirty j^ears were assembled and the volume of w^ater contained in every flood in excess of certain speci- fied rates of flow was computed. These are the volumes of water that would have had to be detained in reservoirs to have reduced the floods of record to the specified rates of maximum flow through reser- voir control. The following table enumerates the streams whose records were analysed, the names of the stream-gaging stations and the i)oi-iod of record : 54 WATER RESOURCES OF CALIFORNIA. LIST OF STREAM FLOW RECORDS ANALYZED FOR FLOOD CHARACTERISTICS. Stream Gaging station Drainage area in square miles Period of record Number of years of record Jellv's Ferry Red Bluff 9.093 9.258 3.627 1.200 262 1.919 534 632 394 983 973 1,543 1,054 1,020 1.034 1,631 1,694 514 264 2,410 577 636 655 214 189 199 Apr. 29. 1895-Jan. 31, 1902\ Feb. 1, 1902-Oct. 1, 19251 •Ian. 1, 1902-Oct. 1, 1925 July 1. 1903-Oct. 1, 1925 Oct. 8, 1904-Oct. 1. 1925 Nov. 4, 1904-Oct. 1. 1925 Oct. 20, 1907-Oet. 1. 1925 30.4 2J 7 Yuba River Smartsville Van Trent 22.3 21.0 20.9 Michigan Bar Clements 17 9 Mokelumnc River Oct. 28, 1904-Oct. 1, 1925 20.9 .Ian. 1, 1907-Oct. 1,1925 18.7 May 19, 1903-May 1, 1916; „ - May 1 1916-Oct. 1, 1925 , .\ug- 30. 1895-Oct. 1, 1925 30.1 Apr. 6. 1901-Nov. 30. 1913: Nov. 28, 191.5-Nov., 19T2}\ 22.5 Nov.. 1922-Oct. 1,1925! San Joaquin River Friant Oct. 18, 1907-Oct. 1, 1925 18.0 Sanger Three Rivers Sept. 3. 189,5-Oct. 1, 1925 30.1 Apr. 29, 1903-Oct. 1, 1925 22.4 Tule River May 1, 1901-Oct. 1,1925 i 24.4 Jan. 1, 1896-Oct. 1. 1925 1 29 8 Jan. 30. 1901-Oct. 5. 1912 ,. , Jan. 1, 1920-Oct. 1,1925 Orland Piitah Creek Oct. 1, 1905-Oct. 1. 1925 ; 20.0 San Gabriel River Azusa Aug. 1, 1895-Oct. 1, 1925 | 30.2 Juiv 1. 1896-Oct. 1, 1914\ „q , Oct. I, 1914-Oct. 1,1925'! After computing the volume of water in all flow.s exceeding; certain ,si)eeified rates, determination was made for each successive day of every flood of the em])ty reservoir s])ace that would have been needed to have absorbed, through the remainder of the flood, all water in excess of the several s])ecified rates of flow. Counts were made in each set of computations ])ertaining to a specified rate of controlled flow of the number of times em])ty space in excess of A^arious values was needed. These counts were expanded by ])roportion to obtain the number of occurrences had the records been a hundred years in length. The rela- tions disclosed by the data on the Sacramento. ]\Iokelumne, San Joaquin and San Gabriel rivers, the four streams selected for illustration, are shown on Plates X, XI and XII, "Reservoir S])ace Required to Control Floods."* These present the relations established from the data between reservoir s])ace and the frequency with which it would be surcharged if used to detain excess flood flows. The horizontal scale on these three i)lates shows the number of days in a hundred years that reservoir sjjace in excess of the values indicated on the vertical scale would be retiuired in a reservoir to reduce floods to the maximum rate of flow specified on the curves. For convenience of com])aris()n between the twenty streams flace.s the maximum di.schar.^e of the Mokelumne River at Clements at 25,500 second feet. Tliis is obtained by appl>iiig the rating curve of the 1911 flood to the KaKc heights of 1907. The crest discharge of tin- 19(t7 flood has been jiublished as 17. , ^. ^ " \ \_ I '•> >S\ s \ \ \ \ . > ^, J \—^ \ \ — — . — :::±V 3 pi k- — V .. — ♦> \ \ i 1 \ \ ' y ^1 \ \ l\ i \ i _ l._ .. — z ^ ^ = i :: ... — = -i: :::: fl 1 1 \ 0.1 100 1,000 10.000 100.000 10,000 SAN GABRIEL RIVER NEAR AZUSA 1,000 ^ ^ c r>J CD « 100 o S 10 E :;; ^ q = ; = : = = = = : Symbr Maiimum to trolled flow 25->ear flood ~ >ccond feet 5 10 i 50 60 1,000 1,900 3.800 5.800 7.700 9,600 11,500 = -J ::: ¥ III 1 aximum c xjntrollet lis w !"* ■t ■ : : ti i:^ ;?^^^" ^Ez\ =^ FTf J. pr- FffT -^ 10% — > ' ^ ~-i ;~--.-_ " T' '-. ~*~~1 f~jL. ,:\ zy^' S 30% 771^ ^^n;?*: ^X^ ^ B ^^ = = :::; ' ~ ::i ^^^^!« x\^\ --^^^^ ::: =q ~ Z :::: \ \ V' ^» Ni 3 \m\ \\ V \ NJ-^ ■y \1 = ::: ^ = 5= h \\\J -^ ^-\ fW ::: = = !:! = ::: ' I + \:V: iV^ti ri 'T ~r ::: — ~ = II!! T V \ i \TT 1 i\ \ i \^ \^ 1 - , ::: = h M 1 4 1 , Ill r-: ::: - - ::: = ::|: ^ — — v~ -: "-^ z i:: ~ :q '-'.'. 1 U ).l I 10 100 1,000 10,000 100,000 Number of days in 100 years on which reservoir space is exceeded Reservoir Space Required to Control Floods CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH RESERVOIR SPACE GREATER THAN INDICATED IS NEEDED TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW. M3)(lmum controlled flow expressed in per cent of Ireat-est daily rate of flow of a once-in-25->e3r flood 56 WATER RESOURCES OF CALIFORNIA. PLATE XI. MOKELUMNE RIVER NEAR CLEMENTS 100,000 01 1 10 100 1.000 10,000 100,000 Number of days in 100 years on which reservoir space is exceeded Reservoir Space Required to Control Floods CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH RESERVOIR SPACE GREATER THAN INDICATED IS NEEDED TO CONTROL FLOODS TO SPECIRED MAXIMUM FLOW Maximum controlled flow expressed m percent of greatest daily rate of flow of a once-in-2&;ye3r flood THE C;ONTKOL OF FLOODS BY RESERVOIRS. 5T PLATE XII, 10,000 ,000 SAN JOAQUIN RIVER NEAR FRIANT o o CO o" ^ ^ cc 100 = =; ::::■ ="■ --: ^4ti -:[-[-! ili ~ ^ T - -- ■ " _- jMaximum rontrolled flow] '--' — - Maximum controllsd flow - : = 2^>ear flood 20 30 40 50 60 70 7.100 10,700 14.200 17,800 21.100 24,900 / .Rain water floodsGO^otolOX) 2oiH/&j 1 ^= -"i -= == : :■ ^ EE e::: ■/— — --] "T"' V 1 1 s 70%2?-^^'"'^ \ S!? ."l-. 1 1 EE 1 — ,\ 7 - -1^;]' '"i"^i "i >s ^^H -;j — — : :! ! N, \l\^ -- --4 \ AT = - = - : i == ::i T= ~S' 1 \f ~\ — ::z : : = : :: 1 \ ' f --'i-- rz 1 -T=Z -]- -. = = E = : = E~ -- :::_ .+- ..„, - — - - — ; L 1 0.1 100 1,000 10,000 100.000 10,000 ,000 too — — M — -++ -m ! -- f = Ma xitnum controlled flow 1 - Max mum controlled flow I 1 25-je3r flood ^^'""'•«' 20 7,100 30 10,700 40 14,200 /<^Snow water floods (302 to 60 '/o) j^ /, r V i 50 1 17,800 <» ■ 60 I 21.400 1 -t- Xv—/: i::iii ' ' 1 ' 1 i i:| = - ► 1 — ^-r~^-- \r,_[ .; in-^ — \, I ■ "^^ S 4^t4o% - 1 L ^*r \ \ : ^^U^ Tf "^S4 .A. \ 1^ ■•heoro t— ^" t t^ __^">%^_„ s — m^ I 1 1 \ \ \ 'N \ \ V- \ \ -p -"f- " * \ t~ I- zz : — -: : — • b^ — — » — i * . 0.1 I 10 100 1,000 10,000 100,000 Number of days in lOOj/ears on which reservoir space is exceeded Reservoir Space Required to Control Floods CURVES SHOW NUMBER OF DAYS IN 100 VELARS ON WHICH RESERVOIR SPACE GREATER THAN INDICATED IS NEEDED TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW. Maximum controlled flow expressed in per cent of greatest dail_y rate of flow of a once-in-25-^e3r flood 58 WATER RESOURCES OF CALIFORNIA. tions were made, the values of reservoir space were expressed in per cent of the greatest daily run-off of a onee-in-25-year flood. The rates of flow were expressed in per cent of the jrreatest daily rate of flow of a 'once-in-25-year flood. The use of these units eliminates the dimensions of the drainage area and permits the ready com})ari,son of data j^ertain- inp; to all drainage areas, irresi)ective of their size. The curves are drawn to ex])ress the trend of the plotted data. Because of the greater mass of statistics pertaining to the smaller flows, the curves relating to them are the most clearly defined by the ])lotted points. The curves for the larger flows are drafted by com- ])arison with those for the smaller ones as well as with those on other streams, while at the same time conforming to the i)lotted points. The data on some streams plot closer to i-egular curves than on others. In determining the general sha{)e of tlie curves greater weight was given to tliese data, believing that the greater regularity indicates fewer departures from a general relation. It may be observed that the plotted data determining the i)arts of the curves in zones of greater frequencies on the right of the graj^hs depart less from the smooth curves than in the zones of smaller fre- quencies on the left, Avhere the points are determined by a less number of floods. The point in each series farthest to the left is computed from the largest flood during the period of record. Although it has been regarded as having an average frequency of once in the period of record, it might well be a flood of some other frequency that happened to occur within this group of years, since the relation expressed by the curves does not take the sequence of flood sizes into account, but only the average interval of time between their occurrence. For this reason the i)eriod of record may contain single floods or even groups of floods that have actual frequencies different from those indicated by their chance occurrence within the period of record. Points representing such floods on the graphs would be expected to depart from smooth curves. The de]nirture of points in the zones of smaller frequencies toward the left on the graphs is believed to be from this cause. Therefore, in drafting the series of curves to re]iresent the average tendency of occurrence, they were drafted neither to average the points nor to pass through as many as i)Ossible, but rather they were drafted as curves of regular shape taking the most reasonable position rela- tive one to the other and to the plotted points and commen.surate with the indications of the data on all the other streams .studied. Relations established. The curves of Plates X, XI, and XII show the relation between reser- voir space and the probable frequency with which specific values would be surcharged if used to detain excess flood flows. They yield informa- tion upon the degree of certainty with which floods nuiy be controlled by reservoirs and the reserve s])ace needed for this purpose. Inter- .sections of the curves on the extreme left vertical, indicate the rpserve s])ace that would be sufficient to detain flows in excess of the values specified on the curves for all except one day of flood in a thousand years. f)n this one day, the indicated reserve sjiace would fill and water in excess of the specified maximum flow would have to be dis- posed of. This day may be one of either small or large flow following THE CONTROL OF FI^OODS BY RESERVOIRS. 59 close upon the great flood that filled the reserve space in the reservoir. The only information yielded by the analysis is that the reserve space would be filled to overflowing. The amount of the overflow in excess of the specified maximum discharge might take any value greater than zero with the greatest likelihood of its being among the smaller values. Intersections of the curves with verticals other than the one on the RESERVOIR SPACE REQUIRED TO CONTROL FLOODS. Maximum controlled Reservoir space in per cent of greatest dail> run-off fl ow of once-in-25-year flood In per _ cent of btream greatest Exceeded Exceeded Exceeded Exceeded Exceeded daily rate In second- one day one day one day one day one day of flow of feet in 1000 in 100 in .50 in 25 in 10 once-in- years years years years years 25-year flood Sacramento River near Red Bluff . 10 24,900 1,200 1.190 1,180 1,165 1,135 20 49,800 620 580 563 548 519 30 74,700 320 282 267 249 223 40 99,600 198 154 140 126 104 50 124,500 148 105 92 78 58 60 149,400 121 80 66 51 32 70 174,.300 102 62 48 33 16 Mokelumne River near Clements** Rain-Water Floods. 20 *3,600 * 1,000 *960 *940 *920 •900 30 5,. 300 322 278 260 237 203 40 7,100 240 189 172 151 119 50 8,900 191 141 122 102 72 60 10.700 153 104 87 69 42 70 12,500 122 76 62 46 21 Snow-Water Floods. 30 5,300 250 1 2.30 1 220 211 195 40 7,100 50 1 40 1 36 30 23 San Joaquin River near Friant ... Raln-Water Floods. 20 *7,100 *I,320 *1.310 *1,300 *1,280 *1,260 30 10,700 243 209 188 168 131 40 14,200 188 154 138 122 94 50 17,800 150 120 106 90 67 60 21,400 123 94 81 68 48 70 24,900 101 74 62 50 32 Snow-Water Floods. 30 10,700 700 678 660 645 622 40 14,200 270 260 250 240 222 50 17,800 130 117 110 102 88 60 21,400 60 51 46 40 30 San Gabriel River near Azusa 5 1,000 419 390 380 370 350 10 1,900 344 295 277 254 225 20 3,800 287 225 200 170 134 30 5,800 243 180 1.54 131 93 40 7,700 220 150 127 102 62 50 9,600 197 128 104 79 37 60 11,500 173 107 85 59 19 70 13,400 153 88 67 40 5 •Rain-water and snow-water floods. ** Water Supply Paper No. 551 of the United States Geological Survey, recently published, places the maximum discharge of the Mokelumne River at Clements at 25,500 second feet. This is obtained by applying the rating curve of the 1911 flood to the gage heights of 1907. The crest discharge of the 1907 flood has been publi.shed as 17,000 second feet in .former publications including Water Supply Paper No. 299 in which are printed the daily discharges of the 1907 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing this volume. Should the daily discharges of the 1907 flood be revi.sed by application of the 1907 gage lieights to the 1911 rating curve, the increase in their values would be so substantial as to require a complete revision of the analyses of floods on the Mokelumne River con- tained in this volume in order to make the analyses harmonize with the increa.seci discharge values. 60 WATER RESOURCES OF CALIFORNIA. extreme left, indicate the probable frequency with which smaller values of reservoir space would fill to overflowing while regulating to the maximum flows specified on the curves. These smaller values of reser- voir space are indicated on the vertical scale opposite the intersections while the frequencies are indicated on the horizontal scale where cut by the verticals intersected. Values determined. Tlie values of reserve reservoir space and the probable frequencies witli which they would be filled to overflowing while controlling floods to the several specified rates are contained in the foregoing table for the four illustrative streams. The units employed are relative to a once-in- 25-year flood and are identical to those used on Plates X, XI and XII. It may be observed in tlie foregoing table that the relative space required to control floods is not extremely different on the several streams for control between 40 and 70 ])er cent of the onee-in-2o-year flood. For control to less than 30 or 40 per cent of the once-in-25-year flood, there is a sharp increase in the reservoir space required on the three northerly streams. On the San Gabriel, however, this sharp increase occurs for control to less than 10 or 20 per cent of the once-in- 25-year flood. On all four streams, for rain-water floods, very much greater space is required if the probability of control is raised from an average excep- tional behavior of one day in 10 years to one day in 1000 years. For control to 70 per cent of the once-in-25-year flood, the space increases from 5 to 32 per cent for an average exceptional behaA'ior on one day in 10 years to 101 to 153 per cent for average exceptional behavior on one day in 1000 years. For control to 40 per cent of the onee-in-25-year flood the space increases from 62 to 119 per cent for exceptional behavior on one day in 10 years to 188 to 240 per cent for exceptional behavior on one day in 1000 years. These values increase to over 1000 per cent for control to less than 10 or 20 per cent of the onee-in-25-year flood on the three northerly streams and to over 400 per cent for control to less than 5 per cent of the once-in-25-year flood on the San Gabriel. The space required to control snoAv-water floods on the two illustrative streams on Avhicli they occur is less than that required to control rain- water floods except for reductions to less than 50 per cent of the once- in-25-year flood. Larger space is required to reduce the snow-water floods to these smaller rates of flow than to correspondingly reduce the rain-water floods. In general, the increase in space for gaining greater probability in control is less for snow-water floods than for those from rain. While there is much similarity on the four illustrative streams in the relative reservoir space refpiired for flood control, the actual space in acre-feet is very ditferent due to the gi-eat variance in Uie .si/e of the four streams. This variance in size is shown by the following table : SIZE OF THE FOUR ILLUSTRATIVE STREAMS. Drainage area Mean seasonal Maxinuim flood in square miles run-off in of record — mean acre-feet daily flow in River second-fret Sacramento 9,258 9,029,000 2.S4.00O Mokelumne 632 898,000 16,700 San Joaquin 1.631 2,057,000 38,800 San Gabriel 214 147,000 22,300 THE CONTROL OF FLOODS BY RESERVOIRS. 61 The actual reservoir space in acre-feet required to control floods, cor- responding to the relative values heretofore presented, are given in the following table. The maximum controlled flows are expressed in second-feet : RESERVOIR SPACE REQUIRED TO CONTROL FLOODS. Maximum controlled flow Reservoir space in acre-feet In per Stream cent of greatest Exceeded Exceeded Exceeded Exceeded Exceeded daily rate In second- one day one day one day one day one day of flow of feet in 1000 in 100 in 50 in 25 in 10" once-in- years years years years years 25-year flood Sacramento River near Red Bluff. . 10 24,900 5,926,000 5,876,000 5,827,000 5,753,000 5,605,000 20 49.800 3,062.000 2.864,000 2.780,000 2,706,000 2..563.000 30 74,700 1,580,000 1,393,000 1,318,000 1,230.000 1.101.000 40 99,600 978,000 760,000 691,000 622.000 514.000 50 124,500 731,000 518.000 1 454.000 385,000 286,000 60 149,400 597,000 395.000 i 326.000 252.000 158,000 70 174,300 504,000 i 306.000 1 237,000 163.000 79,000 Mnkelumnc River near Clements** Rain-Water Floods. *20 3,600 353,000 339,000 332,000 325,000 318,000 30 5.300 114,000 98,000 92,000 84,000 72,000 40 7,100 85,000 67,000 61,000 .53,000 42,000 50 8,900 67,000 50,000 43,000 36.000 25.000 60 10,700 54,000 37,000 31,000 24,000 15,000 70 12,500 43,000 27,000 22,000 16,000 7,000 Snow-Water Floods. 30 5,300 88.000 i 81,000 1 78,000 74,000 69,000 40 7,100 18,000 i 14,000 1 13,000 11,000 8,000 San Joarjuin River near Friant. . . . Rain-Water Floods. *20 7,100 932,000 925,000 918,000 904,000 890,000 30 10,700 172,000 148,000 133.000 119,000 92,000 40 14,200 133,000 109,000 97,000 86,000 60.000 50 17,800 106,000 85,000 75,000 04,000 47.000 60 21.400 87,000 66,000 57,000 48,000 31.000 70 24,900 71,000 52,000 44,000 35,000 23,000 Snow-Water Floods. 30 10 700 494,000 479.000 466,000 455,000 439,000 40 14,200 191,000 184.000 177,000 169,000 1.57.000 50 17,800 92,000 83,000 78.000 72.000 62.000 San Gabriel River near Azusa GO 21,400 42,000 36,000 32,000 28,000 21,000 5 1,000 160,000 149,000 145,000 141.000 133,000 10 1,900 131,000 112,000 106,000 97.000 86,000 20 3,800 109,000 86,000 76,000 65,000 51.000 30 5,800 93,000 69,000 59,000 50,000 35,000 40 7,700 84,000 57,000 48,000 39,000 24,000 50 9,600 75,000 49,000 40,000 30.000 14,000 60 11,500 66,000 41.000 32.000 22,000 7.000 70 13,400 58,000 34,000 26,000 15,000 2.000 *Rain-water and snow-water floods. ** Water Supply I'aper No. 551 of the United States Geological Survey, recently published, place.s the niaxiniuni discharg-e of the Mokelumne River at Clements at 25,500 second feet. This is obtained by applying the rating curve of the 1911 flood to the gage heights of 1907. The crest discharge of the 1907 flood has been publislied as 17,000 second feet in former publications including "Water Supply Paper No. 299 in which are printed the daily di.scharge.s of the 1907 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing this volume. Should the daily discharges of the 1907 flood be revised by application of the 19U7 gage heights to the 1911 rating curve, the increase in their values would be so substantial as to require a complete revision of the analy.ses of floods on the Mokelumne Uiver con- tained in this volume in order to make the analvses harmonize with tlie increa.sed discharge values. 62 WATKR RESOURCES OF CAIJKORMA. Variation in values with time of year and progressive rainfall index. The reservoir space required to control floods deduced by the fore- going anal3^sis is the largest that may be needed under the many cir- cumstances of flood occurrence. It was derived from a discussion of all recorded floods regardless of the time of year or the value of i)rogressive rainfall index Avith which they occurred. The reservoir space required to control floods necessarily will vary with the time of year and value of the progressive rainfall index in a way similar to the size of floods of which it is a function. This relation of reservoir space required to con- trol floods to the time of year and value of progressive rainfall index parallels so closely that of the size of floods which is fully presented in Chapter III, pages 29 to 50, that the plates setting forth the correspond- ing analysis in respect to reservoir s])ace are presented without further comment. Plates XIII and XIV, "Relation of Time of Year to Need of Reservoir Space," are constructed in an identical way to Plates IV and V, "Relation of Time of Yeiir to Flood Occurrence (pp. 30 and 82). Likewise Plates XV, XVI and XVII, "Relation of Progressive Rainfall Index to Need of Reservoir Space," are constructed in a way identically parallel to Plates VII, VIII and IX, "Relation of Progres- sive Rainfall Index to Flood Occurrence" (pp. 44, 45 and 46). The limiting dates for the need of reservoir space to control floods on the four illustrative streams are found to vary not more than 33 days from the corresponding dates of flood occurrence (pp. 34 and 35) while the culminating dates are not more than 11 days apart. Likewise the limiting values of i)rogressive rainfall index with which reservoir space is needed to control floods do not differ more than 16 points from the corresi)onding values with which floods occur and the greatest difference in the most favorable values of the index is 21 points. A complete tabulation of these dates and values of i)rogressive rainfall index follow. These tables are parallel in every respect to those relating to flood occurrence in Chapter 111 (pp. 34, 35, 36, 48, 49 and 50) except that "need of reservoir space to control floods" is substituted for "flood occurrence." THE CONTROL OF FLOODS BY RESERVOIRS. 63 PLATE XIII. SACRAMENTO RIVER NEAR RED BLUFF >mbo Maximum controlled flow | AuA. %ofonce-in ?5-jiear flood Second feet + 30 40 50 60 70 74,100 99,600 I24„>)00 149,400 174.300 .lillY June yMaximum controlled flow to obta n / ' wtiich reservoir space is sometimes nee d- - / ed subseo uent to indicflted date May 1 _ _ --■wC- k_ ■ 'W^ ,^ .\_ - .. ^ ^ .. 1 April -\- . _ , " ~ ■ ■ ■■ 50% ~ ' L .. ,_ 1 ■ "• ^ 1 V\ - - - - ,, - ■ i".:" * *■ ■■•> -- ., 4- / ^- 70 % .,"" !*■> W t l.+ l P Mar . KJ^? /-ilT] ■^v ^ ... - P\X1\ . J^^ _ -> 4f Culminating date 14 Feb. Limiting d^ tes of — t^ ^'-\ ■'^ ^ ^ L?ft ot need oi reservoir ] need of re space to con ervoir _ rol floods . ^fi ^ J \ ^ \ sV-' J^.V^i- space locDnlrol tloods.fl ^.,^^^y './S > / TT 1 Jan. —A + t '.''C V X . f' ' J^ '^'fl "' \^ >' ^" .>C ' , 1 Uec. / 1 .."^''^ > r hh _, --- ' ,' - ^ ' "I _^ ' , ^'f ' 1 -■- Where data ot Iwo or r - — ___ --• ■ — ^^ r 1 1 - ■ - more specified sizes of |- Nov, —! '" _L= ... 50 -b 5^-5 ,-', .^ ■ ' y- r ■ - the symbol of Ihe larjest (- ^/^=^=*- *+ 30% == — - = - — — + L..|. shown. A numeral - placed at Ihe side of 1 Oct. ~~ 4+ ou^ ' , ' '1 s which reservoir space is sometimes nee ed orjor to indicated dates. d- symbols of neit lower bept. order reoresented by it. 1 ' 1 III II 1 1 ' II 1 III O.I 100 1,000 10,000 SAN GABRIEL RIVER NEAR AZUSA 1 Sjmbo Maximum coniroHed flow j Aug 1 %ofonce.in- ?5yeor flood jecond feel I 10 ^8 40 50 60 70 3.800 5,800 7.700 9,600 11.500 13.400 July June t /Maximum controlled tlow to obta ri i i 1 Mav 'which reservoir space is sometimes ne ed subseauent to indicated date d- / s 1 t \ 1 1 1 I 1 [ J^ April ;__ ~Li~'"" "^ ^ IO"oL_JJ M 1 1 -\-V^~-~-:- _r J?'^-~ *" - K 1 ^ "'"-•— 1 "iK---^-^- t,-U., Til ■/ / Mar -^ 1 ~i~. "* r — ~ r ..^ 1 "" > is*i L ^7- ^ _^ 1 ■^ "-n-f ■A*A^ i- "/ " b ■ 1 '...:u tS r\-i ^ V AiJ 1 ^ fi 1 1 .r ,. : , ;; ii ^p,h. Linnitin^ da need of res space to confro i 4 ri'j.^r yf t/j > '^ ' ^1/ _v w^ u . c-uiminaiine Odie of need of reservoir " space to control floods ' 'iMW J* r*l Lr X" ^ri- ^~~^ :rvoir ,]" ^S>C^ <^J<+ tv^ \ /> ^ Jan. >u M.1^^^ ^j'ljt. > ,^ // ^ -^>r U'T Ji'ri L-Hn " ^ > -/]- ;; 70 °o t^ ^^ l^'t-i -vf ^ ^ Dp.c ^:==s43 3 jC^::-**' i>J "i l--'"^^ 1 * ' -^ ■^ 1- . —/^ ^4—*—^ ij-i 5 30 % r"^' ' ^ j.-'T^J J-fT iJ 1 ore specified sizes of ■ owarc coincident, onl) V e Symbol of ttie largest ^ P-— - , $- r^ r 1 1 Nov. Y^ — - -- ■ — - , •" ■ =+ 10% y — ' iS placed at Ihe side of Oct. \m 5 ch symbols which ir> which reservoir space is sometimes nee ed prior to indicated dates. II d cates itie number of d- 5> imbols of next lower " Sept, dec represented by it. 1 1 mill 1 II 1 II II 1 1 1 1 lllll 0.1 I Number of days in 10 100 1,000 10,000 l^'ears on which some reservoir space is needed I Relation of Time of Year to Need of Reservoir Space | CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH SOME RESERVOIR SPACE IS NEEDED PRIOR AND SUBSEQUENT TO INDICATED DATES TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW Maximum controlled flow expressed in percent of greatest dail^ rate of flow of a once-in-25->ear flood 64 WATER RESOURCES OP CALIFORNIA. PLATE XIV MOKELUMNE RIVER NEAR CLEMENTS 1,000 SAN JOAQUIN RIVER NEAR FRIANT 10,000 •laximum controlled flow tor snow waterfloods ro J obtain which reservoir space is sometimes needed ■ Subsequent or pnor to indicated dates. 0.1 I Number of days in 10 100 1,000 10,000 l^ears on which some reservoir space is needed Relation of Time of Year to Need of Reservoir Space CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH SOME RESERVOIR SPACE IS NEEDED PRIOR AND SUBSEQUENT TO INDICATED DATES TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW Maximum controlled flow expi^ssed in per cent of greatest dail^ rate of flow of a once-in-25->ear flood THE CONTROL OP FLOODS BY RESERVOIRS. 65 PLATE XV. 300 z= 200 i\- v> 100 SACRAMENTO RIVER NEAR RED BLUFF — ~ ""T nr >mbol q %ofonce,n- Second feet 74,700 99,600 124,500 149,400 174 300 -- o 40 V 50 « 60 t 70 - V space is sometimes needed with values of pro- ^ ±-^^~ gressive rainfall index j^reafer t|i?n indir^terl ^ 1 ~ ^_ ■V ^ -^ — . . ^^ zim\ Y i -V -^ ^ , i ' — ► T^ •' ■* - \ 1 \ ft ~ ... ^ X"^ — - i" ■»■ -- — »" 1 1 1 t N,^\ 1 1 "-70%^ ' ^ "* 1. " "* ^ ^ >• . / 1 ^ 1 1 •» ^ ^ ' ^ ' ' ^ ^^41 I r ihl» ^a\uf f,f LimitinjS valufs of . "» 1 ■* 1 ' ' "N, "/ -vli- / ' ^l Dlressive rainfall index i r the need of nsservoir I progressive rainfall . index between which reservoir space is needed to control floods •* V > f .w f ---fo ■> ^-f'M S / . V /- + « !* ^ '^ / Ty space to control Tioods. 4v , ^ !^' °!« J 1 1 1 1 1 yi< J/ *t^-3?r : ,oj><, / K 1 1 1 1 1 ~~~/\~ .* ^M^-^^ l":^ K \ Where data of two or 44^ -s= m j..7i2% =^^ '■\\^ ^U Hf- — < — 1 \ flowane coincident.onlj the svTibol or the largest *'T7^ 1 1 [ IS shown A numeral f] 1 i 1 1 { Maxjmurr controlled flow to obtain wtiich reservoir ~ L-- 1 _ IS placed at the sidr of such symbols wh.ch in space IS sometimes needed with values ot pro- gressive rainfall index less than inrjir^tfid dicates the number of i 5 mbols of neit lower 1 ''i 1 Mill 1 iTirlTi'i 1 i onJer repne se nted by ,t.| 100 ,000 10,000 •QO 400 SAN GABRIEL RIVER NEAR AZUSA Manmum conlrolled flon 1 b ymbol %ofonoe m- 25 jear Hood second test 10 20 30 40 y 50 60 70 1,900 3,800 5,800 7,700 9,600 11,500 13,400 . ', f' ' ', ' ' '■ - " / space is sometimes needed with values of pro- /- 300 ^essive rainfall index Greater ^cl indicarea. / • - -. ■\" ~ ■ >. ^ ■ ^ . ■A ■• — >. ,_^ \ •> ""W -=r ^ ■. •^-^ "30% . -< ° „ w L *> ^ ^ , .D -\- •■ *. ^ — '• ' ^ * f- * ^ [~ ■~ -Y — ^ - ., "^ ^ ' .» ^^ 1 *• n v\- • « ■ 50% *^ * a rv( , 200 • « • ^ J %■ 1 •"'■7 "A"\ *• '^ ^ s ' N, h r^ ' -- 1^ " "70% ^ r^ 9 r^ \— - i-=^ _N _ ^^_ k£ W '1- -f--^ _ --/ -Jbj Most favorable va ueof 1 "Li U' c ij< -^ "- 7n r" > ' — ^' •J" - pro|ressive raintall indejcl] :77:rr"rrrrrJi " ♦ *l t '/' /?< iCn '^ i *, ^ toconlrolfloods.j] index betwee ai loii m /\i \ / ^ 7 ^ / space , n^ \^n ^"U- .nA r' reservoir space is " needed to control floods. ' L^ V , / 1 /' ?r f° 100 > / /^, / 3si / .\ / r* ^ ' y ,1 *- V V \ .'f'^: 1 .: /■ V Wher • data of two or =/:= 4 70»^ ^ ^ 4 [>4'0 'iivS < more specified sizes of Z^^ .- ^j> ^ bWI ^^ .li , flow 3 re coinadent.only ■-'.■. i 30% 4 10% r- ^ j-J*T 1 \\. <-' V f J the 5, , IS sho ~ ' 15 niat mbol ot Ihe largest — '— , ff -B^ ^^^ V_ _ ivn. A numeral ^=^ _^X4^: ^ ^- - - Max 1 '•'*'\- — 1 i~\-\-l4 111 * 1 /J 1 1 1.4- ^r suchs ymbols which in ' ' / :e IS sometimes needed with values of pro- symbols -of next lower [1 1 1 1 n 1 1 1 1 1 _ ,sive ra inT dll index Ifib^i JUi UJi IV'-II 0.1 I 10 100 1.000 10,000 Number of days in 100 jears on which some reservoir space is needed Relation of Progressive Rainfall Index to Need of Reservoir Space CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH SOME RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW WITH VALUES OF PROGRESSIVE RAINFALL INDEX GREATER AND LESS THAN INDICATED. Maximum controlled flow expressed in per cent of greatest dail> rate of flow of a once-in-25-_year flood 5—52411 66 WATER RESOURCES OK OALIFORiNIA. PLATE XVI. 400 300 ■- 200 •QO Q- 100 MOKELUMNE RIVER NEAR CLEMENTS ■ TSturfkDd ^8 • 70 5,300 1.100 8.900 10.700 12,500 iMaximum controlled flow for rain /floods to obtain wtiicti reservoir sp sometimes needed witti values of p ive rainfall index greater than inc ::: / ■■ / icated ' ^ " " — ■ - - V — „ ^ "WW.^ ^ ] ' 1 Ihe symbol of the lar^ A - ■ ■* - IS s^own A numeral \ " '^- - . — • » ^ ■ r - . ^ 1 IS placed at Itie side of T - — - . ■ ' 50 % -41 "* ^ f / su* symbols wt)icti in- t-A- ^ ^ •*- ' ** ' *^ <« / dicate: the 5 of number of Q \ \ •■ ' - . , ■ ■• ^ "^ ■ / " > / / symbol next lower fl "* ^ " ^ s/ *" rr ' • ' / • / r - order represented by '• fl ^! •s. * ' " • t/ ' * C« "T^ ; ' / g vail es of pnogresstve \ ■ ^A ^ V^ yK A.x . \* i/i* ^ Vr *^J/^ T^-W.'^^^ reservoir space 15 needed to control ram water floods. - ' ' j^ j^'^ ° ■'^^J^^ r~T — — .' ' s/^l i^'° 'ifc^ ^> ri I'K^ ^ Iressive rainlall I for the need of voir space to con- !- // 'J vy ..^^^C^ ii> • \ i^ ' ' '-* Pi^ /-/- — ^T^^,:^^ 3 h-^ ^'^g^'T-p P^ --!. -— V •^- reser ^■~ i -"■50^g =3 3X1 H ■=^ --^h- >Jtrol rain water floods. H d_ — - ■ - VV-^*, --M Tium controlled flow for ram water - — — ■-- — ' — -1 floods to obtain wtiicti reservoir sp. sometimes needed with values of pro ace IS gress- 3ted. - II L 1 1 1 LJ 1 1 II "" ' - 1 1 0.1 100 1,000 10.000 400 300 200 placed at the Side erf 1 such symbols which in- J T dicale Ihe number 01 J Maximum controlled flow for snow 'floods to obtain which reservoir s( sometimes needed with values of p Symbo s of next lower [] order represented by it. [] / 1 / __. ^ ive ramtall index fir^ater if^n i _ . . _ . - 30% Z^J-LL 1 J" 5^^^>r — - . _ . ■ ■ 40% rzto: • —- ->. ■••1 |j^ _ / 1 ^=~i^ 1 ■ , '>■' _, • ■ -»— 17* ^ If ' i rainlall index between wtiicn reservoir space is needed f control snow water floods ■«. "1 I / * , d progressive ramtall - index Tor the need of reservoir space to con- -1C~ tif uL <''"*=i fl,'' ~"~r>^ -J -r- * ,^ ...JL^ ^ ^ — / " - '.^^ := '" — — — \—^ ' -- 3-+ '^ ._ floods to obtain which reservoir s sometimes needed with values of p 33ce is - rognsss-- ive rainfall index less tha ri ino Tr 1 1 1 Mill 1 1 III 100 1,000 10.000 Number of days in lOO^rears on which some reservoir space is needed Relation of Progressive Rainfall Index to Need of Reservoir Swvce CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH SOME RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW WITH VALUES OF PROGRESSIVE RAINFALL INDEX GREATER AND LESS THAN INDICATED. Maximum controlled flow expressed in per cent of greatest daily rate of flow of a once-ln-25-ycar flood. THE CONTROL OP FLOODS BY RESERVOIRS. ()7 PLATE XVn. o 400 SAN JOAQUIN RIVER NEAR FRIANT Symtwt Majimum umtrolled flow 1 %ofonce-in- 25-«3rni»d Second feet 30 10.100 14,200 n,800 21,400 24,900 60 70 300 1 1 1 1 1 1 Where data of two or more specified sizes of flow are coincident.onl^ =-/ J of pro^'^essive the symbol of the largest I shown. A numeral 11 reservoir space is needed to control ram water floods. placed at the side of f] ^flc ximum controlled flow for rain (water - Ods to obtain wtiich reservoir space is - netimes needed wilti values of progress-- rainfall index greater than indicated; such symbols which in-T dicates the number of -//— / Symbols of next lower 200 / ~ive order represented by it. ¥ 1 /* ^-=4 — : ! — : : : 30i^ . / ' i: : fe"^ ■ — Z'* "^ '. ^ f \ / , 11 ■ loyc . ^ •^ ^* *'*. *■ ^ ' ' / ji - ,» ■« I- ■••'V N KV'i » i /• — |- ' , "^ ^ A ",: \ • > y' V '' , A,' t 7 ^ lyl .1 f. -„U|, ,,,| -jz V •*A\ (Vi \ '- Z-^"^ - ot progressive raintall ndex for the need of reservoir space to con- / > /^ly \n "JfO^ 100 /^:-/rv ^ . .V. -/- — _ -^ ^^ W>'\ r"-^ N F'— = $i -70% ■■50% ^t' -■'f^' ^ t t \ ■ "T ^-^^^^ / — r— l-tT t '*. • — — fin ximum controlled flow for rairi v«Wer ods to obtain wtiich reservoir space is metimes needed witti values of pro- '*"'~7 - 50 n ^' NUl " "V,^ ^4,UJ2n,M JIUJ LU. 0.1 100 1,000 10,000 400 300 I- 200 .cciv,o s u»!h symbols which in^ — f d icates the number of reservoir space is needed to control snow water floods. s ymbols of next lower m m rnntrnlipH fin f 94vi ' c rder represented by it. ximum coniroiieo Tiow lui .juvn wwwi^i / eded with values of pro|ness- ' -// / son letimes ne y ive rainfall index grj ^1 i " ^n<^ ■J-IU _ ■" ~ " ■ 30% - — — — - , - ■ — — J hf — ; - : E ■ , \ ~ ~ • ■ ■- - .^ w -.'-,• • —h / / — — — - 1 . :: i-^»-i t. 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O/O j' > o d o cO o o o « o b O"" zzacQ <2 3 B .g oooor- -Ht^ ii Bo > > >^ u b 0/ o.« ZZZQQ <2 .s o i lllll SS V3 c ♦* •^ u iflTi- oo'o'c-i lO t>-' O * £ S a B S sc 3 § ll^l^l SLfe. Ml gssgg THE CONTROL OP FLOODS BY RESERVOIRS. 69 ' &i OOTMIiOiO 1 0; cq Ci T3 >, M a-S-g-g ^^^ c °.2 S^fefepM S's 3 3 >-^'-5l-5l-= 1 c ^2 CO 00 1^ t- 05 —1 (M« IM CO to 05 '« ■a >> fe S ^-^-^ _>._>._>i g ll 3^5 0_c -?SS[S£ ■3 "3 "3 3 t--a 'ot3 > S g "rf -IS §3 &i t^cOC^l^rC »(5 to Oi CO ■x) t. 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C/3 o > 05 u b o Q z 0; o Ui H <; Q o z >>« t^ I - a> 02 -* t~ CD S rq-H C<) "O >, 2o 3 1-H .-H 1 c >>s c^ CO i^ CO >n CO — ■ IM C-l — 1 CM ■a >> ll to ra 0.3 "- '- rt ffl S ^-^ t-O l-s S_M rt 2*3 >.i ^ t- —I to CO to T3 «- J3 03 s •-H CMC^lrt T3 >> 1 So 3S t^ iZ C ^ ^ *^ ^ 0, a D.^ £ i! — si- 5-S >.i t^ OS CO 05 ^ 00 CO ^S^ Ti e^i cq « -H >. >2 CO 00 o) >a> =« S-. rt rt CO C~J C-l ■^^ <5i a. D. Q. Q.^i2>2 c ""* >.i 0> 10 Tf cc -< -a >. go S S 1= 3-g °.s \z;Cia4>4!Z -a 1 3 >>« »-< »o t^ ai 05 00 1^ ca S rtCO >-IC. S O3 > > g g ,-• jj D. ;z;:z;GQQ.«.« ^ S .^ ca (O -S »'S s; >.« to (35 —1 rt t^ ■* -a £-g ea S "O >> 3 p 3g > > d CJ cj o' ^ dJ OJ « QJ " 'b C3 ^:?;qqqq4| D. "55 li ^ a. S ."ti >. ca CO >n UO ■* CM 00 & rt C^l -H — CI >. oo •^ > > d tj cj u 32 aj Qj a; .g t^ t^ to -^ to 05 « §s CM - > > > u d o2 o OtISO ta ? OJ 05 00^00 t^ tO_u3 -^^ T3 — T CO b-" Oi" ^ CO* to -H 1^ M as ^ 3 3 a g s ^ t^ * •p ^i S.s« 00 00 S-fe = "iS ^ 0- S'Sg?;, 70 WATER RESOURCES OP CALIFORNIA. CULMINATING DATE FOR NEED OF RESERVOIR SPACE TO CONTROL FLOODS. Maximum controlled flow Date In per cent of greatest daily rate of flow of once-in-25-year flood Sacramento River near Red Bluff Mokelumne River near Clements San Joaquin River near Friant San Gabriel River near Azusa Rain-water floods Snow-water floods Rain-water floods Snow-water floods 10 Feb. 7 20 Feb. 7 30 40 50 Feb. 4 Feb. 4 Feb. 4 Feb. 4 Feb. 4 Feb. 22 Feb. 18 Feb. 15 Feb. 14 Feb. 12 May 28 June 7 Jan. 18 Jan. 19 Jan. 20 Jan. 21 Jan. 22 May 26 June 4 June 5 June 6 Feb. 7 Feb. 7 Feb. 4 60 Feb. 4 70 Feb. 4 SACRAMENTO RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX* BETWEEN WHICH RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS. Maximum controlled Minimum index values Maximum index values flow near Red Bluff Frequency with which some reservoir space is Frequency with which some reservoir space is In per needed, with progressive rainfall index needed, with progressive rainfall index cent of less than values tabulated greater than values tabulated greatest In second- daily rate of flow of foct One day One day One day One day One day One day One day One day One day One day 25-ycar flood in 1000 in 100 in 50 in 25 in 10 in 1000 in 100 in 50 in 25 in 10 years years years years years years years years years years 30 74,700 42 47 49 52 58 212 206 202 197 188 40 99,600 46 61 54 58 65 205 199 194 188 178 50 124,500 50 56 59 64 72 199 191 186 179 164 60 140,400 54 60 64 70 81 193 183 177 167 148 70 174,300 57 64 68 76 95 188 176 168 155 127 *At Red Bluff rainfallstation. THE CONTROL OF FLOODS BY RESERVOIRS. 71 MOKELUMNE RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX* BETWEEN WHICH RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS. Maximum flow near controlled Clements Minimum index values Maximum index values Frequency with which some reservoir space is needed, with progressive rainfall index less than values tabulated Frequency with which some reservoir needed, with progressive rainfall i greater than values tabulatec In per cent of greatest In second- feet space IS adex daily rate of flow of once-in- 25-year flood One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 years years years years years years years years years years Rain-Water Floods. 30 40 50 60 70 5,300 7,100 8,900 10,700 12,500 50 56 62 68 74 55 61 67 74 81 58 64 71 78 86 62 69 77 86 97 70 78 88 103 240 226 212 200 188 228 213 198 185 172 222 207 191 177 163 215 199 183 168 151 204 186 169 150 S new-Water Floods. 30 40 5,300 7,100 67 83 68 84 69 85 70 86 72 164 89 156 163 154 162 153 161 151 159 149 *At Electra rainfallstation. SAN JOAQUIN RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX* BETWEEN WHICH RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS. I Maximum flow nea controlled r Friant Minimum index values Maximum index values Frequency with which some reservoir space is needed, with progressive rainfall index less than values tabulated Frequency with which some needed, with progressive greater than values reservoir rainfall tabulatec In per cent of greatest daily rate In space IB ndex j of flow of once-in- 25-year flood second- feet One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 One day in 1000 One day in 100 One day in 50 One day in 25 One day in 10 years years years years years years years years years years Rain-Water FloodSj 30 40 50 60 70 10,700 14,200 17,800 21,400 24,900 45 53 60 66 71 47 55 62 69 74 49 57 65 71 77 52 60 68 76 83 59 70 79 89 101 190 186 182 179 176 185 181 177 173 169 183 179 174 170 164 179 175 170 164 157 173 167 160 151 140 Snow-Water Floods. 30 40 50 60 10,700 14,200 17,800 21,400 60 69 77 84 62 71 80 88 64 73 82 91 65 74 84 94 68 77 88 101 150 143 138 134 148 140 134 129 147 139 133 127 146 137 131 125 144 135 128 119 *At Fresno rainfallstation. 72 WATER RESOURCES OF CALIFORNIA. SAN GABRIEL RIVER. LIMITING VALUES OF PROGRESSIVE RAINFALL INDEX* BETWEEN WHICH RESERVOIR SPACE IS NEEDED TO CONTROL FLOODS. Maximum controlled Minimum index values Maximum index values flow nca r Azusa Frequency with which some reservoir space is Fre(iiicncy with which some reservoir space 18 In per needed, with progressive rainfall index needed, with progressive rainfall index cent of less than values tabulated greater than values tabulated greatest In daily rate of flow of second- feet One day One day One day One day One day One day One day One day One day One day once-in- in 1000 in 100 in 50 in 25 in 10 in 1000 in 100 in 50 in 25 in 10 25-year flood years years years years years years years years years years 10 1,900 27 30 32 35 40 294 282 277 270 257 20 3.800 35 39 41 45 51 279 264 256 245 226 30 5,800 42 47 49 53 61 265 248 238 226 203 40 7.700 48 54 57 63 78 252 233 222 207 181 50 9,600 54 59 66 77 102 241 219 206 189 158 60 11,500 58 66 76 90 127 230 205 191 173 133 70 13,400 63 73 86 106 220 193 178 156 *At Claremont rainfall station. MOST FAVORABLE VALUES OF PROGRESSIVE RAINFALL INDEX FOR NEED OF RESERVOIR SPACE TO CONTROL FLOODS. Maximum controlled flow Sacramento Hivor near lied Bluff Mokelumnc River near Clements San .loacpiin River near Friant San Gabriel [n per cent of greatest daily rate (if How of once-in-25-ycar flood Haiii-water floods iSnuw-water floods liaiii-wat( r floods SiiDW-waler floods Itiver near Azusa 10 122 20 117 30 40 50 110 110 110 111 110 130 129 128 128 125 120 120 122 122 122 122 122 no no no no 121 126 118 60 130 70 1X1 THE CONTROL OF FLOODS BY RESERVOIRS. 73 CHAPTER V. THE RESERVOIR OPERATING DIAGRAM FOR CONTROLLING FLOODS. Principles of operating reservoirs for controlling floods. The use of reservoirs for flood control in California, being of c«m- paratively recent date, has not been standardized by the engineering profession. The practice varies. In general, reservoirs now in use for flood control have allotted either the entire or a specific part of their capacity for this purpose alone. The usual method of operation is to hold this entire space empty at all times except as it may be tempo- rarily filled while detaining excessive flood flows and the water that accumulates while thus controlling floods is released as soon as the streams subside in order that this .space may be empty for the control of the run-off of subsequent storms. Any water that is retained in storage is held upon the prediction of the reservoir operators that the space occupied by it will not be needed again that season for controlling floods. The prediction that floods will not occur again in any season involves an estimate of future weather conditions, the most uncertain of all events. When water is stored in flood control reservoirs on such an estimate, an error results in failure in control of subsequent floods because the reservoir space needed to detain excessive rates of flow would already be filled with water held from the first storm. Failure in the control of floods means the loss of property and sometimes of human life. Were this danger not real, flood control reservoirs would not be built. For matters of such importance, it would seem unsafe to rely upon the judgment of operators in the most uncertain of predic- tions, especially since the decisions of gravest moment must be made during the stress of large floods. The risk of an error in judgment under these circumstances is too great for attaining surety in protec- tion. For this reason the use of flood control reservoirs for conserva- tion purposes generally has not been looked upon with favor. For a like reason, many engineers propose the exclusion of manually operated gates on the outlets of flood control reservoirs. Contention is made that the risk is great in relying upon human activity of any kind during critical periods ; rather, they would have the reservoir discharge its water and empty automatically through ports in the dams with fixed openings. This view, however, would seem to be somewhat extreme, for it is now common practice to place manually operated gates in the spillways of reservoirs. These are closed toward the end of the run-off season in order to utilize the top layers of the reservoir for storing water. They are opened again after the summer's draft has lowered the reservoir level, but before the next season's rains. Should the attendants fail to open these gates, the capacity of the spill- way would be destroyed and a fair-sized flood would overtop the dam. [n spite of this danger, reliance is placed on the manual operation of these gates to clear the spillway prior to the occurrence of a flood. 74 WATER RESOURCES OP CALIFORNIA. The manual operation of control mechanism is customary in many other lines of endeavor -where the safety of life and property is involved, especially in our transportation system. Custom relies upon hand- controlled signals, valves and steering apparatus for the safety of life and property in all modes of transportation. Dispatchers, tower men, engineers of railroads, auto-bus drivers, and captains of ocean-going vessels, in the faithful and exact performance of their duty, hold within their hands the safety of millions of passengers and va.st wealth. These men are required to operate apparatus under guiding rules. Judgment, other than that necessary for applying the guiding rules, is not needed. Because of the many successful years of the operation of our trans- portation systems on both land and water, it would seem that the man- ual . operation of apparatus under guiding rules is quite safe. By analogy, therefore, it would not seem necessary for safety to exclude the use of manually operated gates on the outlets of flood control reser- voirs, provided that guiding rules, definite and enforcible, be laid down for their opening and closing. Without gates controlled by hand on the outlets of flood control reservoirs, a coordinated use of their space for both flood control and eon.servation is impossible. Gates that may be closed when desired are necessary in order that flood control reservoirs may store water for any length of time. Therefore, the safe use of the same reservoir space for both flood control and conservation is contingent upon working out definite guiding rules for opening and closing the outlet gates that do not employ judgment in their execution and that can be enforced. Rules for opening and closing reservoir outlet gates that will control floods with certainty may be worked out easily enough if no attempt is made to avoid interference with the conservation values of the reser- voirs. To produce rules, however, that will hold sufficient reservoir space empty during the flood season to assure the successful control of floods while at the same time releasing this space as the season pro- gresses so that it ma.y fill with water before the end of the run-off season, is a complex undertaking. It has been the purpose of these investiga- tions to develop the principles upon which such rules might be scien- tifically constructed and, by way of illustration, to construct several rules, test tlieir accuracy and determine tlieir effect on conservation. These principles have been developed in the foregoing chapters. The construction of the rules, the test of their accuracy and the determina- tion of their effect on conservation occupy this and the concluding chapters. The reservoir operating diagram. it lias been pointed out in the preceding chapters, that the same amount of reservoir space is not needed for controlling floods at all times during a season nor in all seasons. The amount of space needed under the many circumstances of time of year and type of season is iletermined by the analysis of the need of reservoir space for controlling floods described in the previous pages. In general, the amount of space needed for detaining excessive flood flows so that only limited amounts pass the reservoir increases from zero in the early fall to a maximum in midwinter and tlien, as the season progresses, decreases to zero in the forepart of summer. It also fluctuates with the normalcy of the THE CONTROL OF FLOODS BY RESERVOIRS. 75 season's precipitation. In general, summarizing the deductions of the first four chapters, when the seasonal precipitation to date is less than half or more than double normal, large floods do not occur. Under these conditions, reservoir space is not needed for flood control regard- less of the time of year. It is needed in the largest volume when the precipitation to date is between normal and 50 per cent above. The largest floods occur under these circumstances and the maximum reser- voir space is then required for controlling floods. Space in amounts intermediate between zero and the maximum is necessary when the seasonal precipitation to date is between 50 and 100 or between 150 and 200 per cent normal. The exact value of these requirements varies with each stream and the degree of control desired. The amount of reservoir space required under the many variant cir- cumstances of time of year, type of season, and degree of desired control may be specifically derived through analyses similar to the ones in the preceding chapters. Having determined these amounts, rules may be laid down that will release the space required for flood control as soon as its need for that purpose has passed. This space may then fill for con- servation. The dependability of such rules for controlling floods rests upon the selection of adequate amounts of space to be held empty during the flood season. Their value to conservation rests upon the immediate release of this space for filling as soon as its need for flood control has passed. Thus, the determination of the amount of space that should be held empty during the flood season and of the time that all or part of it may be released safely for filling is the foundation for formulating rules for the combined use of the same reservoir space for both flood control and conservation. The rules, as devised by this investigation, are expressed in the form of graphic diagrams which show the amount of reservoir space that, for the circumstance existing on any current day, should be empty in order to assure the degree of flood control desired. The reservoir outlet gates would be opened or closed daily as may be necessary to provide within 24 hours the required empty space indicated on the diagram. The gates would be opened when this space is less than indicated and the discharge through the outlets is less than the desired maximum con- trolled flow. The gates would be closed whenever the empty space in the reservoir is greater than indicated on the diagram. All inflow to the reservoir would then enter storage except as water may be with- drawn for some useful purpose. These graphic rules are called "Reservoir Operating Diagrams for Controlling Floods." Each diagram applies to a particular stream and to a particular degree of control. The degree of control is expressed by the maximum controlled flow desired at some point of measurement and the probability that this will not be exceeded. This probability is measured in the analyses herein described by the number of days in an average hundred years on which greater flows may occur. The greater the assurance of perfect control, the larger is the amount of reservoir space required and the longer is the period during which it should be held empty. Practical values in accord with the danger to life and property must be selected for design purposes in each instance. For sparsely settled rural lands, it is thought that adequate protection would be had if the desired maximum controlled flow were exceeded on 76 WATEi: KESOUKC'ES OF CALIFORNIA. PLATE XVI II. ■) 100 200 300 400 50 20 July ^ 10 1 _ — — 20 June 10 Reservoir outlet gates to be opened or closed daily as may be necessary to provide wahin 24 hours the unoccupied space indi- cated on diagram for the current day and value of progressive tainfall index. Release from reservoir limiled in rate in order that, in combinin| with run-off downslream from reservoir the maximum controlled Tlow will not be exceeded at point of measurement. Curved lines on diagram are marked with values of the pro- gressive rainfall index. Black lines are used for values of iTO or less and red lines for greater values. 20 May ^ 10 i 20 April ^ 10 1 1 U, ~~~^ts~^ \ 20 Mar 10 ■-~^^^~''^ ^ ■^^^=^=5= ^3B=^ ==; ^^~~-- "^-^^IT ^^^a H:, ^ ^^^^_i l"'"""^-^ =^ ^ ^^^ ■-^ -^ p~^. _i '^, ~ "S^t-..^ ^^~~-^ '~-~^^*^*'^« r~~« <: ::^_ «,^ ,^^ ' ^^^'^^^^i^--' ' ^^^^ f^^'^^ "^* ^"^ tf=^ ^""^^^^ 1^ -NS, ^"O \ ^ "- ^ ^^ ">«. 20 Feb '"^ "vj ! ^V:' fc. "^si "^ ■C ■^ \ s<^ !n^ ^ ■\ - '65, ^^ ! 75 Xi 80 \ 85 V) 9Kl0Kll0->, \ \ "^ \\ Nl N > N\ \N\^ \ 1 > iu \ \ \ ^ H \\ \ A \ n 1 \ ' \ I \ V \ w 5 9 1 ' 1 ] - J, J \ Jan. '* 10 j / / / / / f i' 1) /// / \Jf / / /y A V j/y 6 180/ yio / 160 / isq/- ij<5 \Xi^yiy Jf y^ '/! ^ ^L^ /. '^ ■, y^\^^ y^ \ , ^ 1 ^ / >- ^ /Jr X ^ 1^ ' 1 \ / ^ r .^ — >r >^ ^^ l*^ \ 20 Dec. 10 V'^X ^.-V''^ \^^ ^ ^^ "^^^^^ 5^* \ / ■^/ . ^ r^ ^,t<^^\^y^ ,^' ^^^^2^--^^, --■■''^ / ^JL-^^\^ >^ ^^^ ::::^^ =***Dr -Tj ^r'-ir^ 1S-*1 g ^^t-*f^ ^*^ F***"^ ^ ^ ^ ^=— ^ 20 Nov. 10 ^ ^ ss^ 20 Oct. 10 ' • 100 200 300 400 Reservoir space in thousands of acre feet 500 Reservoir Operating Diagram FOR Controlling Floods on Sacramento River MAXIMUM CONTROLLED FLOW NEAR RED BLUFF-125,000 SEC. FT. CURVES SHOW SPACE NEEDED AT VARYING TIMES OF YEAR AND VALUES OF PROGRESSIVE RAINFALL INDEX TO ABSORB EXCESSIVE FLOOD FLOWS. i2411 — rage 76 THE CONTROL OP Ff.OODS I?Y REl^ERVOIRS. 77 an average not oftener tlian one day in 25 years, while for very thickly populated territory, it probably should not be exceeded oftener than one day in a thousand years or more. After selecting the degree of control desired, a reservoir operating diagram for controlling floods may be constructed for any stream from the analyses of its flow measurements. This diagram would apply only to reservoirs having drainage areas between them and the point of measurement that do not produce floods greater than the selected maximum controlled flow. In releasing water from reservoirs located upstream from the point of measurement, the amount would be gov- erned by the flow at the point of measurement. The release from the reservoir would be limited to an amount that, combined with the natural run-off from the drainage area downstream, would not exceed the desired controlled flow at the point of measurement. The analyses of stream flow data required for the construction of a reservoir operating diagram are identical to those described in Chapter IV. The analyses there described of the stream flow data on the Sacra- mento, Mokelumne, San Joaquin and San Gabriel rivers furnish infor- mation for the construction of reservoir operating diagrams for any desired degree of flood control on these four streams. The construction, from this information, of a diagram for one selected degree of control on each of the four streams is described in the following pages of this chapter. For convenience in working with these diagrams, the use of the name "progressive rainfall index" that represents the normalcy of seasonal precipitation in the analyses of Chapters III and IV has been con- tinued. It is the ratio of the precipitation from July 1st up to any current day in a season to the normal precipitation for the same period. Its value changes daily as the season progresses. In using the diagrams, it is necessary to maintain a rain gage in order to obtain the current value of the progressive rainfall index. This gage should be read and the value of the progressive rainfall index computed on each day. The diagram should be entered with this value and the amount of space read-off that should be empty at the end of the current day. The outlet gates should then be regulated to obtain this empty space so far as may be done without causing a flow at the point of measurement greater than the desired maximum. If the reservoir outlet gates were so regulated daily, by reason of the method of constructing the diagram, the reservoir would not be expected to fill to overflowing except at the average intervals contemplated in the selection of the degree of probable control. At these average inter- vals, the reservoir would be expected to overflow while the maximum controlled flow is passing the point of measurement. Thus, the maxi- mum controlled flow below the reservoir may be exceeded by the amount of this overflow at the average intervals selected in the construction of the diagram. The amount of the overflow might be anything larger than zero with the greatest likelihood of its being among the smaller values. Reservoir operating diagram for controlling floods on Sacramento River. Plate XVIII, "Reservoir Operating Diagram for Controlling Floods on Sacramento River," presents in graphic form the rule for operating 78 WATER RESOURCES OF CALIFORNIA. a reservoir on the main Sacramento River in order to limit the flow in the channel near Red Bluff to 125,000 second-feet. It indicates the space in the reservoir that should be empty in order to detain run-off in excess of this desired regulated flow for all conditions of previous rainfall on every day of the season. The amount of space that should be empty changes with the time of year and the normalcy of the season's precipitation as shown by the value of the progressive rainfall index. A maximum of 454,000 acre-feet is required to be empty in the fore part of February if the precipitation up to that time is 10 per cent above normal. On preceding and subsequent days the space required becomes less until prior to November 21st and subsequent to April 8th, no space is needed at all. The required space also becomes less for seasonal precipitation to date either larger or smaller than 10 per cent above normal and reaches zero for precipitation greater than 186 per cent or less than 59 per cent normal. Had there been a reservoir in existence and operated in accord with til is diagram through the thirty years of stream flow record on the Sacramento River, the flow at Red Bluff would not have exceeded 125,000 second-feet at any time. Even the greatest flood of record on February 3, 1909, which reached a crest discharge of 278.000 second- feet, would have been limited to a flow of 125,000 .second feet, 153.000 second-feet less than the actual occurrence. Although controlling floods to this discharge, the diagram holds space in the reservoir empty no longer than necessary. Thus, the nde of reservoir operation laid down by this diagram interferes a.s little as possilile with the use of the reser- voir for conservation. The diagram applies to any reservoir of more tlian 454.000* acre- feet capacity that might be constructed on the main Sacramento River between the Red Bluff' gaging station and the Kennett reservoir site near the confluence with the Pit River. It does not apply to reservoirs further upstream than Kennett because it is estimated that a flood as large as 125,000 second-feet may originate on the drainage area down- stream from Kennett but tributary to the Red Bluff gaging station. The values of the progressive rainfall index used in the construction of the diagram were computed from the rainfall records of the United States Weather Bureau at Red Bluff". t These values are marked on the curved lines of the diagram. Black lines are used for values of no or less and red lines for greater values. The intersections of the curved lines with the horizontal date lines indicate on the lower scale the amount of empty space needed at any time. The diagram assumes that the reservoir outlet gates will be opened or closed daily as may be necessary to provide as nearly as possible within 24 hours Avithout causing the desired regulated flow to be exceeded, the empty space indicated on the diagram for tbe current day and value of progressive rainfall index. If the reservoir were located upstream from Red Bluff", the release through the outlet gates would be limited to amounts that would not exceed 125,000 .second-feet after combining with the run-off from the drainage area between the reservoir and Red Bluff. • The reservoir space nooded for flood control in addition to 454,000 acre-feet is that which would furnish the minimum operating head on the reservoir outlets to dis- charge 125,000 second-feet. t Red Bluff is one of the principal stations in precipitation division B of which most of the flood producing arta of the Siicramento Drainage Basin is part. See Chap. II, Bui. 5, "Flow in California Streams," issued by the Division of Engineering and Irri- gation, State Department of Public Works. THE CONTROL OF FLOODS BY RESERVOIRS. 79 The degree of control selected for construction of the Sacramento River diagram contemplates that the desired regulated flow may be exceeded on an average of one day in fifty years. This was used in taking values off the charts of Chapter IV for constructing the diagram. The maximum reservoir space required under the most severe circum- stances is taken from Plate X, p. 55. In the upper figure on this plate, reading the 50 per cent curve (124,500 second-feet), it is found that reservoir space in the amount of 92 per cent of the greatest daily run-oif of a once-in-25-year flood (454,000 acre-feet) is sufficient, on the aver- age, to control floods to 125,000 second-feet maximum flow at Red Bluff on all but one day in fifty years. The time at which this maximum space is required is taken from the upper figure of Plate XIII, p. 63. The intersection of the full and dotted-line curves labeled 50 per cent (124,500 second-feet) determines that the culminating date of need of reservoir space to control floods is February 4th. This date and the maximum reservoir space needed locate on the diagram the apex of the outside curve, the one of largest values of reservoir space. The two arms of the outside curve are fixed in position by their inter- sections with the vertical line on the left representing zero reservoir space. Their intersections with this vertical read on the time scale are at the days before and after which reservoir space is not needed to control floods. These dates are determined on the upper figure of Plate XIII, p. 63, by the intersection of the 50 per cent curves (124,500 second-feet) with the vertical representing two days in 100 years on which some reservoir space is required to conti'ol floods. The full-line curve intersects at November 21st, the date before which reservoir space is not needed. The dotted-line curve intersects at April 8th, the day after which reservoir space is not needed. These two dates, plotted on the operating diagram on the line of zero reservoir space, fix the position of the arms of the outside curve. With the apex and the position of the two arms fixed, the shape of the curve was estimated from a study of the data on twenty major streams in California and by the trial construction of diagrams. The shape given is the one that seems to fit the data best. This curve, outermost of all others on the diagram, expresses the largest values of reservoir space that are required at any time. The amount of space indicated by it should be held empty wdien the condi- tions of previous rainfall are most favorable for the need of reservoir space to control floods. The value of the progressive rainfall index most favorable for the need of reservoir space is taken from the upper figure of Plate XV, p. 65. Here the dotted and full-line curves repre- se'iiting control to 50 per cent of a once-in-25-year flood (124,500 second- feet) intersect at a value of 110 read on the scale of progressive rainfall index. This is the most favorable value for need of reservoir space to control floods and hence is the value of the progressive rainfall index that applies to the outside curve of the operating diagram. The interior curves that indicate the empty space required with values of the progressive rainfall index either greater or less than the one calling for the largest amount of empty reservoir space are drawn of a shape similar to the outside curve. There is one black curve for each increment of five in the values of the progressive rainfall index less than 110, and one reel curve for each increment of ten in 80 WATER RESOURCES OF CALIFORNIA. PLATE XIX. 20 40 60 80 100 20 July 10 Sv 20 June ^ \\ < m 120 H \ i w ■<^ "~\ >v ■---, >i ^^ n; Sw. % s ■ "N vN ^s^ ■"■^ 1^^, ^ -i^ ^ s« V) \50 N ,90 \ 100 "< s 110^ o^e^ao^ > ^ \, \ \ \ \ ^ N^ ■> N "v N ^^ N \ \\ \ 1 \ k \ \ \ 20- Feb. 10 9, \ . \ , i j i 1 / , / /// / / ' I - t-1^^ / /// 22 2 210 2I(/ 2oq 190 / 180 > 170 /1 60 150 140 20 Jan 10 / / "7 // / // / /\ ' / / / / ^// / i // / / / A v^ y / Za /l y / / / ^ y / 'J / // y V / iy ■^, / f f / y ^y ^^^ ^y *^ // 20 Dec. 10 J ' / ^/ ^ y -^ l^ J^ ^ / / /. ' \y ^ ^ ^^ ^ If / / t y / ^ y' ^ ^ ^ d ^^ Progressive rainfall index/ / y^ / ^ ^ ^ fe <^ aSP ^ / S« ^ ^ ^ >^^ ;> 0^ ^ 20 Nov. 10 ^ /^ '^ ^ ^ Reservoir outlet gates to be opened or closed daily as ma> b necessary to provide within 24 hours the unoccupieo space indi cated on diagram for the current day and value of progressive rai fall index. Release from reservoir limited in rate in order that in combining with runoff downstream from reservoir, the maximun controlled now vvill not be exceeded at point of measurement Curved lines on diagram are marked with values of the pro^re ive rainfall index. Black lines are used for values of 130 or e 1 55- 20 Oct. 10 less for rain-water and 120 or less for snow-water floods. 1 20 40 60 80 Reservoir space in thousands of acre feet IC Reservoir Operating Diagram FOR Controlling Floods on Mokelumne River MAXIMUM CONTROLLED FLOW NEAR CLEMENTS FOR RAIN WATER FLOODS - 5,300 SEC. FT. SNOW WATER FLOODS - 7J00 SEC. FT. CURVES SHOW SPACE NEEDED AT VARYING TIMES OF YEAR AND VALUES OF PROGRESSIVE RAINFALL INDEX TO ABSORB EXCESSIVE FLOOD FLOV\/S. 52411— Page 80 TTTE OON'PROT^ OF l''I,OOnS liV RKSKRVOIHS. 81 the values of the progressive rainfall index greater than 110. The curve of smallest index value is 65 and largest 180. Both are close to the zero ordinate of reservoir space on the diagram. The index values coinciding with the zero ordinate of reservoir space are 59 and 186. These are the limiting values hetween which reservoir space is required to control floods. No space is needed when the index is either smaller or larger, respectively. These values are derived from Plate XV, p. 65. In the upper figure on this plate, the two 50 jier cent curves (124,500 second-feet) intersect the vertical representing two days in 100 years that values will be exceeded, at 59 and 186 on the vertical scale of progressive rainfall index. The intersection of the full-line curve shows that, for values of the pi-ogressive rainfall index less than 59, reservoir space is not reciuired oftener than two days in 100 years. Similarly, the intersection of the dotted-line curve sliows that reservoir space is not required to control floods except for two days in 100 years when the progressive rainfall index exceeds 186. The positions of the apices of the several interior curves on the diagram are interpolated between the outside curve of maximum reser- voir space and zero on the reservoir space scale along the line repre- senting February 4th, the culminating date for need of reservoir space in controlling floods. They are not arranged with uniform intervals between them, but rather take positions having increasingly smaller intervals as the maximum reservoir space is approached. The arms of the interior curves are drawn of the same general shape as the outside curve and are interpolated in position with increasingly smaller inter- vals between them toward the latter part of the flood season. While normally the arms toward the fore part of the flood season would take similar positions, since at this time of the year the index values fluctuate rapidly and are not well established, they are all passed through November 21st on the zero reservoir space line, the opening date of the flood season. This manner of fixing the positions of the apices and arms of the interior curves was found to fit the data best after construction of many trial and supplementary diagrams on this and other streams and for other degrees of flood control. Reservoir operating diagram for controlling floods on Mokelumne River. The rule for operating a reservoir to control floods on the Mokelumne River is expressed on Plate XIX, "Reservoir Operating Diagram for (Jontrolling Floods on Mokelumne River." As on the one for the Sacramento River, the Mokelumne River diagram indicates the space in a reservoir that should be empty on each day of the season for all conditions of previous precipitation in order to detain discharges in excess of a certain desired controlled flow. The Mokelumne River dia- gram would limit the flow near (Mements,* the point of measurement on the Mokelumne River, to a maximum of 5)300 second-feet for rain-water floods and 7100 second-feet for snow-water floods. The diagram applies to any reservoir within a distance of about 80 miles upstream from Clements. The reservoir would need to have a capacity greater than 92,000* acre-feet, the maximum space required. The Mokelumne dia- gram, like that for the Sacramento, assunu>s that the reservoir outlet * The reservoir space needed for flood control in addition to 92,000 acre-feet is that which would furnish the minimum operating head on the reservoir outlets to dis- charge 5300 second-feet. G— 52411 82 WATER RESOURCES OP CALIFORNIA. gates will be opened or closed daily as niaj- be necessary to provide as nearly as possible Avithin 24 hours without causing a tlow at Clements greater than desired, the empty space indicated on the diagram for the current day and value of progressive rainfall index. The chief distinction betAveen this diagram and the one for the Sacra- mento River is that it provides for controlling snow-water floods in the early summer. These do not occur on the Sacramento but are a part of the normal regime of tiie ]\Iokelumne River. The Mokelumne dia- gram provides for limiting their maximum rate of discharge to 7100 second-feet, 1800 second-foet more than tlie maximum controlled flow for rain-water floods. It is estimated that these two controlled flows would be about equivalent one to the other in the lower channel of the river because the snow-water flow will be reduced by summer diver- sions for irrigation while the natural run-off downstream from the point of measurement will contribute some to the regulated rain-water floods. The greatest rain-water flood contained in the twenty-one years of stream-flow^ record at Clements occurred on January 30, 1911. The crest discharge was 20,600* second-feet, 15,300 second-feet larger than the controlled floAv to which rain-water floods would be limited by reservoir operation in accordance with the diagram. The mean daily flow on January 30, 1911, was 16,700 second-feet. The largest snow- Avater flood appears in the record on June 12, 1906, Avitli a discharge of 8740 seeoud-feet. Tliis is only 1640 second-feet larger than the con- trolled snow-water floAv that would result from use of the diagram. Since snow-water floods do not attain as great a rate of floAv as those from rain water, large reductions are not necessary in order to con- fine them to a channel of reasonable size. For this reason the reser- voir space required for the control of snow-water floods on the Mokel- umne River is much less than for the control of rain-Avater floods. The greatest space required in order to limit snoAV-Avater floods to 7100 second-feet is 13,000 acre-feet. A maximum of 92,000 acre-feet is required to limit rain-Avater floods to 5300 second-feet. On the Mokelumne diagram during the period of rain-Avater floods, the greatest space is held empty Avhen the progressive rainfall index has a value of 130 and during the period of snoAV-Avater floods, Avhen it has a A'alue of 120. The curves in ))lack indicate the space to be held empty for index values less than 130 and 120. respectively. Avhile the curves in red indicate the space to be lichl empty for greater index values. The extreme values between Avliieli any iv.servoir space is needed at all are 58 and 222 for rain-Avater floods and So and 153 for snoAv-Avater floods. These differ someAvhat from the corresponding values on the Sacramento River diagram. Similarly, the limiting dates of the flood season are slightly different. Unlike the Sacramento dia- gram, hoAvevei', that for tlie ^lokelumne liohls a small amount of .space • Water Supply Paper No. 551 of the United States GeolOK>cal Survey, recently published, places the maximum discharge of the Mokelumne River at Clements at 25,500 socond-ffot. This is obtained by applying the rating curve of the 1911 flood to the page heights of 1907. The crest rti.scharge of the 1907 flood has been published as 17,000 second-feet in former publications including AA'ator Supply Paper No. 299 in which are printed the daily di.«5charges of the 1907 tlood. The figures contained in AVat<-r Supply Paper No. 299 have been used in preparing this volume. Sliould the daily discharges of the 1907 flood be revised by application of the 1907 gage heights to the 1911 rating curve, the increase in their values would be so substantial as to require a complete revision of the analyses of floods on the Mokelumne River con- tained in this volume in order to make them harmonize. THE CONTROL OF FLOODS BY RESERVOIRS. 83 empty between May lltli and July otli for the control of snow-water floods that do not occur on the Sacramento River. The diagram for controlling floods on the Mokelumne River is con- structed in a way identical to that previously described for the one on the Sacramento River; the same probability of average exceptional behavior of one day in 50 years was selected, and the values are taken in exactly the same way from the analyses of Chapter IV which were carried out in parallel for the four illustrative streams. The values of the progressive rainfall index used in the Mokelumne River analyses were computed from the records of the United States Weather Bureau station at Electra.* This is the station at which the rainfall index should be determined in applj'ing the diagram. The maximum reservoir space required on the Mokelumne diagram under the most severe circumstances is taken from Plate XI, p. 56. Reading the 30 per cent (5300 second-feet) curve for rain-water floods and the 40 per cent (7100 second-feet) curve for snow-water floods, the reservoir space required for flood control except probably on an average of two days in 100 years is 260 per cent of the greatest daily run-off of a once-in-25-year flood (92,000 acre-feet) for the control of rain- water floods and 36 per cent (13,000 acre-feet) for the control of snow- water floods. The culminating date of the two flood seasons, at which time ilie maximum empty space is needed, is determined from the upper figure of Plate XIV, p. 64. Here, on the part pertaining to rain-water floods, the intersection of the dotted and full-line curves labeled 30 per cent (5300 second-feet) shows the culminating date of the season to be Feb- ruary 22d; on the part pertaining to snow-water floods, the intersection of tiie dotted and full-line curves labeled 40 per cent (7100 second- feet) shows the culminating date of the snow-water flood season to be June 7th. These two dates on which maximum empty space is needed fix the position on the time scale of the apices of the two sets of curves of the reservoir operating diagram. The positions of the arms of the outside curves are fixed by the limiting dates of the flood season. These dates are taken from the upper figure of Plate XIV, p. 64. On the part of this figure per- taining to rain-water floods, the intersections of the two 30 per cent (5300 second-feet) curves with the vertical representing two days in 100 years on w^hich some reservoir space is needed to control floods, give November 17th and April 21st as the limiting dates of the flood season. Similarly, on the part pertaining to snow-water floods, the two 40 per cent (7100 second-feet) curves intersecting on the same vertical indicate the limiting dates for this season to be May 11th and July 5th. The arms of the outside curves on the reservoir operating diagram pass through these dates on the line of zero reservoir space. The .shape of the curves was determined by the preparation of supplementary and trial diagrams in the same way as for the Sacramento River diagram. The value of progressive rainfall index Avith whicli this maximum reservoir space is needed is taken from Plate XVI, p. 66. Here the intersections of the full and dotted-line curves labeled 30 per cent ♦ Electra is a cooperative station of the United States Weatlier Bureau and one of tlie principal stations in precipitation division K of which the Mokelumne drainage basin is part. See Chapter II, Bui. 5, "Flow in California Streams," issued by the Division of Engineerinjj and Irrigation, State Department of Public Works. 84 WATER RESOURCES OF CAUFORXIA. PLATE XX. c 40 80 12 iO 160 20 20 July ^ 10 -= = = ^~~- ;r~ »._^ 20 June 10 L-^ ..^ ^^ -..^^ ---. ■»N^ ■^ "•-«, •^ 75 80 90 -^ 100 ■t«^ " \ \ \ \ > 73 --1' 9 ; 7 ) i 1 20 May ^ 10 ^ ^ 130 ^ ' 1^ --^ ^ — ^^^ '-' . «••"* i '^^i^ s= M ^ -^ 20 April ^ 10 t>. -^ 20 Mar. 10 ?N ^^ 5-~^ ?=5 t^ ^ Pr ogressive rainfall index^ "~- ^ '--^ -:^ r^ s^ !5^ 1 ^-^ [^ "■ ^-> ^ >x; l*^ ^* 1 ^ ^- "^ ^ -^ ^^ 1 1 20 Feb. 10 ■'"V **^^ ^ "^ On. 'i^ s^V, ^ j ^^ ^ "V, ^^ :^^ 1 "v N "^ ^ \ \ \. ^ s[Ni^ 1 S, \ N N N ^V j \ ^ \ \ k^ 1 \ 60 \ 70 \, 80 mi2o' 20, Jan ' 10 50 V \ \ \ \ \N^ \ 1 \ \ \ \ 9 I ) / / / / / / \ / t:i7 80 y 170 / IfiO / 1S(/ \M^ 1 20 Dec 10 ?,^ 1 / / / / y/ / / // y y ^^ / ^ > y '^ ^/ ^ ^ / ^. ^^^ 20 Nov. 10 — / ^ /> ^ ^ >^ ^',<: ^y* ^^ ^i^ Reservoir outlet gates to be opened or closed daily as may be necessary to provide within 24 hours the unoccupied space indi- cated on diagram for the current day and value of progressive rain- fall index. Release from reservoir limited in rate in order that, in combining with run-off downstream from reservoir, the maximum controlled flow will not be exceeded at point of measurement. Curved lines on diagram are marked with values ofthe progres'' ive rainfall index. Black lines are used for values of 120 or less for rain-water and 110 or less for snow-water floods Red lines are used for greater values in each instance. / "^ ^ >-' ■< s*^ -^ ^ ^ ^ 20 Oct. 10 ^ >* 1 1 1 1 1 1 1 1 1 1 1 1 1 1 40 80 120 160 200 Reservoir space in thousands of acre feet Reservoir Operating Diagram FOR Controlling Floods on San Joaquin River MAXIMUM CONTROLLED FLOW NEAR FRIANT FOR RAIN WATER FLOODS - 10,700 SEC. FT. SNOW WATER FLOODS -14,200 SEC. FT. CURVES SHOW SPACE NEEDED AT VARYING TIMES OF YEAR AND VALUES OF PROGRESSIVE RAINFALL INDEX TO ABSORB EXCESSIVE FLOOD FLOWS ■ 2411 — Page 84 THE CONTROL OF FLOODS BY RESERVOIRS. 85 (5300 seeond-feet) for rain-water floods and 40 per cent (7100 second- feet) for snow-water floods indicate valnes of 130 and 120, respectively. These are the index valnes of the ontside cnrves on the operating diagram whose apices indicate respectively on the reservoir space scale the niaximnm empty space of 92,000 acre-feet for rain-water floods and 13.000 acre-feet for snow-water floods. The interior cnrves are drafted in comparison witli the exterior curves after interpolating the positions of their apices between that of the outside curve and the line of zero reservoir space and the positions of tlie arms of the curves between the limiting and central dates of the flood season as in the preparation of the Sacramento River diagram. There is one black curve for each increment of 10 in the progressive rainfall index valnes less than that most favorable for the need of reservoir space to control floods and one red curve for each similar increment greater than the most favorable value. The values of the progressive rainfall index that apply to the curves of smallest and largest valnes whicli are coincident with the line of zero reservoir space on tlie operating diagram, and above and below which reservoir space is not needed to control floods, are obtained from Plate XVI, p. 66. On the i)art pertaining to rain-water floods, the intersections of the dotted and full-line curves labeled 30 per cent (5300 second-feet) with the vertical representing two days in 100 years on which values will be exceeded, yield limiting values of the ])rogressive rainfall index of 58 and 222; while on the part pertaining to snow-water floods, the inter- sections of the dotted and full-line curves labeled 40 per cent (7100 second-feet) yield limiting values of 85 and 153. Reservoir operating diagram for controlling floods on San Joaquin River. The rule for operating a reservoir on the San Joaquin River for flood control is delineated on Plate XX, "Reservoir Operating Diagram for Controlling Floods on San Joaquin River." This diagram is quite the same as the one for the Mokelumne River except tliat snow-water floods become relatively more important and require more reservoir space for their control than rain-water floods. The nuiximnm space re(juired to conti-ol I'ain-Avater floods is 133,000 acre-feet while 177,000 acre-feet are required for the conti'ol of snow-water floods. This maxi- mum space for rain-water floods is needed on January 18th and for snow-Avater floods on June 4th wlien the values of the progressive rain- fall index are 122 and 110, respectively. The space required on these and other dates when the index values are less than 122 for rain-water and 110 for snow-water floods, is indicated by the several black curves labeled with smaller index values. The red curves indicate the space required when the index values exceed 122 and 110, respectively. The diagram applies to any reservoir within a distance of about 30 miles upstream from Friant, the point of measurement on the San Joa- quin River. With a capacity greater than 177,000* acre-feet the appli- cation of the rule would result in limiting rain-water floods to a maximum flow of 10,700 second-feet and snow-water floods to a maxi- mum flow of 14,200 second-feet at the i)oint of nu'asurement. It is estimated, because of diversions for irrigation from the snow-water * The reservoir space needed for flood control in addition to 177,000 acre-feet is that which would furnish the minimum operating head on the reservoir outlets to dis- charge 14,200 second-feet. 86 WATER RESOURCES OP CALIFORNIA. flows and accretions to the rain-water run-off downstream from the point of measurement, that these two regulations will produce approxi- mately an equivalent effect in the lower channel of the river. With the exception of a small fall flood occurring on October 2, 1918, M'ith a mean daily discharge of 10,900 second-feet, the diagram will control all floods shown in the eighteen years of continuous record by the United States Geological Survey. The flood of January 31, 1911, with a mean daily flow of 38,800 second-feet was the largest during this period. It was 28,100 second-feet greater than the maximum con- trolled rain-Avater flow that would be obtained by application of the diagram. The largest snow-water flood during the period occurred on June 13, 1911, when the mean daily flow was 23,100 second-feet. This is 8900 second-feet larger than the maximum controlled snow-w'ater flow that would be obtained by application of the diagram. The San Joaquin River diagram was constructed from data taken from the analytical graphs of Chapter IV in a way identical to that for the construction of the diagrams for the Sacramento and Mokelumne rivers. The same probability that the desired maximum controlled flow may be exceeded on an average of one day in 50 years was used. The values of the i)rogressive rainfall index for the San Joaquin River were computed from the records of the United States Weather Bureau at Fresno.* This station sliould be used for determining the index values in applying the diagram. The positions of the apices of the outside curves along the scale of reservoir space are taken from Plate XII, p. 57. Reading the 30 per cent curve (10,700 second-feet) for rain-water floods and the 40 per cent curve (14,200 second-feet) for snow-water floods, it is seen that, for full control except probably on an average of two days in 100 years, the maximum space required is 188 per cent of the greatest daily run-off of a onee-in-25-year flood (133,000 acre-feet) for the control of rain-water floods, and 250 per cent (177,000 acre-feet) for the control of snow-water floods. The dates on which this maximum space is required, the culminating dates of tiie two flood seasons, are taken from the lower figure of Plate XIV, p. 64. On tlie part of the figure pertaining to rain-w'ater floods, the intersection of the dotted and full-line curves labeled 30 per cent (10,700 second-feet) shows this to be January 18th. On the part pertaining to snow-water floods, the intersection of the dotted and full-line curves labeled 40 per cent (14,200 second-feet) shows this date to be June 4th. The arms- of the outside curves of the diagram have their positions defined by the limiting dates of the flood season taken from the lower figure on Plate XIV, p. 64. Here, on the part pertaining to rain-water floods, the intersections of the two 30 per cent (10,700 second-feet) curves, one dotted and one full-line, with the vertical representing two days in 100 years on which some reservoir space is needed to con- trol floods, give October 22d and April 7th. Similarly, on the part of the figure pertaining to snow-water floods, the two 40 per cent curves (14,200 second-feet) intersect the same vertical at April 27th and July 16th. These are tlie limiting dates of the two flood seasons before * Fresno is one of the princiiial stations in precipitation division Q of which the San Joaquin drainage ba.sin is part. See Chap. II, Bui. 5, "Flow in California Streams," issued by the Division of Engineering and Irrigation, State Department of Public Works. THE CONTROL OF FLOODS BY RESERVOIRS. 87' and after which reservoir space is not needed to control floods. The positions of the arms of the interior curves and their shapes were deter- mined as for the Sacramento and Mokelumne river diagrams. The index values with which the maximum reservoir space is needed were obtained from Plate XVII, p. 67. Here the intersections of the full and dotted-line curves labeled 80 per cent (10,700 second-feet) for rain-water floods and 40 per cent (14,200 second-feet) for snoAV- Avater floods indicate values between 110 and 122 as being most favor- able for the need of reservoir space to control both rain and snow-water floods. These are the index values of the outside curves of the diagram. The index values for the extreme inside curves are taken from the same plate. On the part pertaining to rain-water floods, the intersections of the two 30 per cent (10,700 second-feet) curves, one dotted and one full-line, with the vertical representing two days in 100 years on which values will be exceeded, indicate limiting values of the index of 49 and 183. Keservoir space is not needed to control floods with either smaller or larger values than these. On the part of the figure pertaining to snow-water floods, the corresponding limiting values are found to be 73 and 139. The index values for the several interior curves on the operating diagram are interpolated between these and the values for tlie outside curve the same way as for the diagrams of the Sacramento find IMokelumne rivers. Reservoir operating diagram for controlling floods on San Gabriel River. Plate XXI, "Reservoir Operating Diagram for Controlling Floods on San Gabriel River," delineates the rule for operating a reservoir on this stream in order to control floods with least interference in its con- servation use. Like the diagrams for the Sacramento, Mokelumne and San Joaquin rivers, that for the San Gabriel indicates the space that should be empty on each day of the flood season for the amount of seasonal precipitation to date, in order that excess flood waters may be detained. The curves in black indicate the space that should be empty when the value of the progressive rainfall index is less than 120 and the red curves the space when the value is greater than 130. The dia- gram assumes that the reservoir outlet gates will be opened and closed as may be necessary to pi'ovide within 24 hours as nearly as possible, without causing the desired regulated flow to be exceeded, the empty space indicated on the diagram for the current day and value of progres- sive rainfall index. The San Gabriel River diagram is like that for the Sacramento River in that it does not provide for the control of snow^-water floods. The snow on the San Gabriel drainage area that lasts until early summer is too small in quantity to do more than help sustain the summer flow of the stream when it melts. The diagram applies to any reservoir whose dam is within a distance of about 5 miles upstream from the Azusa gaging station, the point of measurement. A capacity of 131,000 acre-feet available for flood control purposes would be required. The application of the rule to the operation of a reservoir of this or greater capacity would result in limiting flood flows to 1900 second-feet at Azusa gaging station. A much larger flow than this will pass safely down the channel of the San Gabriel River to the ocean but it could not all be conserved. It is 88 WATER RESOURCES OF CALIFORNIA. PLATE XXL 30 60 90 120 150 20 ^"'^ ,0 20 June 10 Reservoir outlet gates to be opened or closed daily as may be necessary to provide within 24 nours The unoccupiec space indi- cated on diagram for the current daji and value of progressive rainfall Index. Release from reservoir limited in rate in order that, in combining^ with run-off downstream from reservoir the maximum controlled flow will not be exceeded at point of measurement. Curved lines on diagram are marked with values of the pro- gressive rainfall index. Black lines are used for valuesof 130 or less and red lines for greater values. 20 May ^ 10 20 April ^ 10 ' ^^^ :S5-i- " ^^^^^ ^ ■ ~^^i!^^^5=5ft=>> 20 Mar. 10 _"~'^~~^^^'^^^^^^^rr--^>_ ^ ^'■^■^^T--^.,,//*'^ ^ S:^ . -"-C^ — ^■^J "^^ — ~ ^^ ■~^H F^ — ., ■*=5 =^:^^ S:5~- ,_^ i~^--^ ^~~" R- !:> ^^.:^-*^>:s p5^ ■ — -.^...^ ' -•-«.^^ ■*^ ~" — ~i "^"^^^^ "^i.,^ .^ '"^ ^~~ ^-sj ^^ *=^ K ^^^ ■^. ■^ ■ \ *^ ^~s. ^^~" 5^^^^ L 20 Feb. ^"-^ "V, X , v^ Sv "-J>v rs!' s^ziyu >30 \ ^ s 50 X 60 \70 1 "^0 siHXt r-l20&l30 \N \ ^ N N. \ \N < N\ V>\ V 1 \ \ \ \ \ \ \ \ w \ 7 J ]| ) \ \ l| \ || 1 1 II ]\ \ 1 20. Jan. " 10 i , / 1 / U 11 j / 1 , 1 // ihll 5j 2= (7 280 ik 260 240 no/ lot 150 I6Q / , f f / /f uA ' ^ / / / /, / //A // / / / y / / ^/ A y/^ / ! 20 Dec. 10 \ 1 / ^ 1 / / ' J^ ^ '^^ / / 1 / 1 / // /, ^ y^ ^ / ' / y / / / //f y y ^ ^ / /, / / J ^ ^y ^' X ^ / / / / -^ ^^ A^ // 1 y^ / /> <^ ^ ^ ^^•^i--^^*^ / 20 Nov. 10 P " / /^ ^i -^ '^ ^ '^^^^^""'^ Progressive rainfall index / ^\ / -J ^^ J^/ ^ '^^^i""'^ ^^^ ^^ i^**^ ^ 20 Oct. 10 1 ; • ! ■ 30 60 90 120 Reservoir space in thousands of acre feet 15 Reservoir Operating Diagram FOR Controlling Floods on San Gabriel River MAXIMUM CONTROLLED FLOW NEIAR AZUSA- 1,900 SEC. FT. CURVES SHOW SPACE NEEDED AT VARYING TIMES OF YEAR AND VALUES OF PROGRESSIVE RAINFALL INDEX TO ABSORB EXCESSIVE FLOOD FLOWS. .24 11 — Page 8S THE CONTROL OF FLOODS BY RESERVOIRS. 89 believed that flows up to 1900 seeond-feet may be conserved conven- iently by sinking tlieni into the large underground basin of the San Gabriel Valley. This makes it desirable to reduce the San Gabriel River floods to a much smaller flow than on the other illustrative streams. The largest flood in the thirty years of stream flow record at Azusa occurred on January 18, 1916. with a crest flow of 40,000 second-feet. This is 38,100 second-feet greater than the controlled flow that would result from the application of the diagram. The greatest mean daily flow of the 1916 flood was 22,300 second-feet. The diagram for the San Gabriel River was constructed from the analytical graphs of Chapter IV in a manner similar to that employed in the construction of diagrams for the other three illustrative streams. Instead, however, of using the probability that the desired maximum controlled flow may be exceeded on an average of one day in 50 years in taking information from the charts as in the preparation of the other diagrams, a frequency of one day in a thousand years was selected because of the greater property A'^alues and population concen- trating below the San Gabriel dam. The records of the United States Weather Bureau rainfall station at Claremont* were used in computing values of the progressive rainfall index for the San Gabriel River. This is the station that should be used in the application of the diagram. The apex of the outside curve on the San Gabriel diagram has its position determined on the reservoir space scale from the largest empty space that is required under the most severe circumstances as shown on the lower figure of Plate X, p. 55. The intersection of the 10 per cent curve (1900 second-feet) with the vertical representing full control except on an average of 0.1 day in 100 years (one day in 1000 years) shows that the maximum reservoir space required is 344 per cent of the greatest daily run-off of a once-in-25-year flood (131,000 acre-feet). Its position on the time scale is fixed by the date most favorable for the need of reservoir space for the control of floods. This is taken from the lower cut on Plate XIII, p. 63. The intersection of the dotted and full-line curves labeled 10 per cent (1900 second-feet) indicates February 7th as the most favorable date. The positions of the arms of the outside curve of the diagram are also determined from Plate XIII, p. 63. Here the dotted and fidl-line curves labeled 10 per cent (1900 second-feet) intersect the vertical of 0.1 day exceptional behavior in 100 years (one day in 1000 years) on October 27th and April 19th, respectively. These are the limiting dates of the flood season before and after which reservoir space is not needed for the control of floods to the degree selected. The value of the progressive rainfall index with which the greatest reservoir space is needed is taken from the lower figure of Plate XV, p. 65. The intersection of the full and dotted-line curves labeled 10 per cent (1900 second-feet) marks tlie index value 122 as being most favorable for the need of reservoir space. The outside curve that indicates the need of most s])ace is given a value of from 120 to 130. * Claremont i.s a cooijcrativo station of the United States Weatlier Buroau and ono of the principal station.s in precipitation divi.sion W of which the San Gabriel (Irainagre basin is part. See Chap. II. Bui. No. .^), "Flow in California Streams," issued by Division of Engineering and Irrigation, State Department of Public Works. 90 WATER RESOURCES OF CALIFORNIA. The index value for the extreme inside curve is taken from the same plate. The intersections of the two curves, one dotted and one full-line, labeled 10 per cent (1900 second-feet) with the vertical on the extreme left representing an exceptional behavior of 0.1 day in 100 years (one day in 1000 years), give limiting values for the index of 27 and 294. Reservoir space is not needed for controlling floods when the index is either smaller or larger than tliese values. Therefore, 27 and 294 are the index values of the black and red curves respectively that are coin- cident with the line of zero reservoir space. The other interior curves are interpolated in position between these and the outside curve as in the construction of the diagrams for the other three illustrative streams. Performance of the four illustrative reservoir operating diagrams in controlling floods, not coordinated with conservation. The performance in controlling floods of the four reservoir operating diagrams just described has been tested by applying them respectively to the records of daily flow on each of the four illustrative streams. It was assumed that a reservoir of required capacity existed at the point of measurement on each stream, that it was full at the beginning of each flood season, that it was held as nearly full as the diagram Avould ])ermit during the succeeding flood season, and that water was released from storage only as required to gain the empty space indicated on the diagram. The following tables sliow for all* tlie largest floods of record, both rain and snow-water, the dates on whicli the reservoirs would have been nearest full and the amount of space still empty ou those daj'^s. It may be noted that all floods of record on the four illustrative streams would have been controlled witliout the reservoirs overflowing except a small fall flood on the San Joatiuin, occurring on October 2, 1918, with a discharge of only 200 second-feet in excess of the maxi- mum controlled flow. On the Sacramento River even tlie liistoric floods of March 20, 1907, and February 3, 1909. would have been controlled with 53,500 and 188,800 acre-feet of space to spare respectively at the times the reservoir was nearest full. The average space to spare at the times nearest full while controlling all floods on the Sacramento River during the entire thirty years of record would have been e(|ual to half the space required under the most severe circumstances. • All floods exceeding the desired maximum regulated flow are listed when their number is less than twenty, otherwiae the twenty largest are tabulated. THE CONTROL OF FLOODS BY RESERVOIRS. 91 SACRAMENTO RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING ALL FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1895-1926 Not Coordinated with Conservation Maximum flood flow — uncontrolled Flow controlled to 125,000 second-feet ma.timum near Red Bluff Reservoir space not used in controlling flood Mean daily flow in second- Date reservoir nearest Date feet near full In per cent of maxi- Red Bluff In acre-feet mum space required for flood control (454,000 acre-feet) Feb. 3, 1909 254,000 Feb. 4, 1909 188,800 42 Feb. 2. 1915 249,000 Feb. 2, 1915 200,900 44 Mar. 20, 1907 196,000 Mar. 21, 1907 53,500 12 Jan. 16, 1909 188,000 Jan. 18, 1909 191,400 42 Feb. 16, 1904 188,000 Feb. 16, 1904 357,700 79 Jan. 21, 1909 177,000 Jan. 21, 1909 150,700 33 Feb. 25, 1917 176,000 Feb. 25, 1917 109,300 24 Feb. 21, 1914 160,000 Feb. 21, 1914 119,600 26 Jan. 1, 1914 151,000 Jan. 2, 1914 129,900 29 Feb. 24, 1902 151,000 Feb. 26, 1902 289,100 64 Mar. 8, 1904 147,000 Mar. 8, 1904 332,400 73 Feb. 10, 1902 140,000 Feb. 12, 1902 327,600 72 Mar. 31, 1906 137,000 Mar. 31, 1906 105,500 23 Jan. 19, 1906 136,000 Jan. 19, 1906 143,600 32 Feb. 4, 1907 134,000 Feb. 4, 1907 433,500 95 Jan. 25, 1903 131,000 Jan. 25, 1903 431,700 95 Mar. 7, 1911 130,000 Mar. 7, 1911 368,400 81 Jan. 27, 1896 128,000 Jan. 27, 1896 341,500 75 Average 237,500 52 I 92 WATER RESOURCES OF CALIFORNIA, MOKELUMNE RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING TWENTY LARGEST RAIN WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1904-1926 Not Coordinated with Conservation Maximum flood flow— uncontrolled Flow controlled to 5300 second-feet maximum near Clements Reservoir space not used in controlling flood Mean daily flow in second- Date reservoir nearest Date feet near full In per cent of maxi- Clements In acre-feet mum space required for flood control (92,000 acre-feet) Jan. 30, 1911 16,700 Feb. 1, 1911 35,200 38 Mar. 19, 1907 15,310 Mar. 27, 1907 7,100 8 Jan. 2C). 1914 11,100 Jan. 27, 1914 68,900 75 Jan. 14, 1909 10,400 Jan. 17, 1909 5,200 6 Feb. 21, 1914 9,850 Feb. 21, 1914 82,700 90 Feb. 6, 192.5 9,700 Feb. 6, 1925 27.800 30 Jan. 1, 1914 9,250 Jan. 1, 1914 36,100 39 .Tan. 21, 1909 8.400 Jan. 22, 1909 8,500 9 Mar. 20, 1916 8,040 Mar. 21, 1916 64,400 70 Feb. 2, 1907 7,860 Feb. 4, 1907 79,300 86 Mar. 31, 190tj 7.750 .\pril 1, 1906 49,600 54 Mar. 23, 1907 7,610 Mar. 27, 1907 7,100 8 Jan. 22, 1914 7,47i) ,Ian. 22, 1914 78,600 85 ,Jan. 18, 1921 7,350 ,Tan. 18, 1921 75,700 82 Mar. 7, 1911 7,210 Mar. 11, 1911 70,900 77 Nov. 21, 1909 7,200 Nov. 21 1909 . Feb. 11, 1919 7,060 Feb. 11, 1919 29.000 32 Jan. 19, 190(i ■ 6,960 Jan. 19, 1906 24,400 27 Mar. 12, 1918 6,940 Mar. 12, 1918 9,400 10 .\pril 16, 192.5 6,910 .■^pril 17, 1925 6,600 7 Average 38,300 42 THE CONTROL OF FLOODS BY RESERVOIRS. 93 MOKELUMNE RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING ALL SNOW WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1904-1926 Not Coordinated with Conservation Maximum flood flow— uncontrolled Flow controlled to 7100 second-feet maximum near Clements Reservoir space not used in controlling flood Mean daily flow in second- Date reservoir nearest Date feet near full In per cent of maxi- Clements In acre-feet mum space required for flood control (13,000 acre-feet) June 12, 1906 8,740 June 13, 1906 1,900 15 June 18, 1911 8,030 June 18, 1911 3,300 25 June 3, 1922 7,970 June 5, 1922 2,600 20 June 12, 1911 7,960 June 12, 1911 3,100 24 June 6, 1911 7,880 June 6, 1911 4,000 31 May 31, 1922 7,770 June 1, 1922 6.700 52 June 1, 1915 7,750 June 1, 1915 10,000 77 May 18, 1922 7,670 May 19, 1922 1,800 14 June 16, 1906 7,600 June 17, 1906 4,500 35 June 10, 1917 7,550 June 10, 1917 2,900 22 May 24, 1911 7,500 May 24, 1911 800 6 July 4, 1906 7,480 July 4, 1906 1,100 8 Average 3,600 28 SAN JOAQUIN RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING ALL RAIN WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1907-1926 Not Coordinated with Conservation Maximum flood flow — -uncontrolled Flow controlled to 10700 second-feet maximum near Friant I Reservoir space not used in contrr lling flood Mean daily flow in second- Date reservoir nearest Date feet near full In per cent of maxi- Friant In acre-feet mum space required for flood control (133,000 acre-feet) Jan. 31, 1911 38,800 Feb. 1, 1911 14,200 11 Dec. 31, 1909 27,900 Jan. 1, 1910 43.600 33 Jan. 14, 1909 26,800 Jan. 15, 1909 16,400 12 Dec. 10. 1909 26 800 Dec. 10, 1909 28.200 21 Jan. 26, 1914 24,700 Jan. 30, 1914 13,800 10 Jan. 21, 1909 18,900 Jan. 22, 1909 62,700 47 Mar. 8, 1911 18,800 Mar. 8, 1911 67,400 51 Mar. 10, 1911 13,600 Mar. 12, 1911 55,900 42 Feb. 12, 1909 12,500 Feb. 14, 1909 104,100 78 Feb. 21, 1917 11,700 Feb. 21, 1917 100,700 76 April 6. 1911 11,600 April 6, 1911 Jan. 18, 1916 11,000 Jan. 20, 1916 113.100 85 Mar. 21, 1916 11,000 Mar. 21, 1916 15,100 11 Oct. 2, 1918 10,900 Oct. 2, 1918 Jan. 25, 1911 10,700 Jan. 25, 1911 79,300 60 Average 47,600 36 94 WATER RESOlTRf'ES OF CALIFORNIA. SAN JOAQUIN RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING ALL SNOW WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1907-1926 Not Coordinated with Conservation Maximum flood flow— uncontrolled Flow controlled to 14200 second-feet maximum near Friant Reservoir space not used in controlling flood Mean daily flow in second- Date reservoir nearest Date 1 feet near full 1 In per cent of maxi- Friant In acre-feet mum space required for flood control (177.000 acre-feet) June 13. 1911 23.100 June 23. 1911 21,100 12 June 4, 1909 22.800 June 8. 1909 89.100 50 June 16. 1911 21.500 June 23. 1911 21.100 12 July 7.1911 19.500 July 7. 1911 57,600 33 June 5. 1922 16.700 June 8, 1922 149.700 85 May 22. 191 1 16.200 Mav 23. 1911 134.600 76 June fi. 1911 16.200 June 8. 1911 165.500 94 May 8. 1909 1O.200 May 8, 1909 39,300 22 June 2. 1914 15.700 June 2. 1914 167,500 95 June 5. 1912 15.300 June 5. 1912 33,000 19 June 15. 1909 14.900 June 15. 1909 95.000 54 June 27. 1911 14.700 June 28. 1911 38,200 22 May 31. 1922 14.700 June 1. 1922 171.200 97 June 24. 1909 14.600 June 24. 1909 129,300 73 .\veraEf 93,700 1 53 SAN GABRIEL RIVER UNUSED RESERVOIR SPACE WHILE CONTROLLING TWENTY LARGEST FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1895-1926 Not Coordinated with Conservation Maximum flood flow — uncontrjUed Flow cantrolled to 1900 second-feet maximum near Azusa Reservoir space not used in controlling flood Mean daily flow in S3cond- Date reservoir nearest Date feet nerr full In per cent of maxi- .\zusa In acre-feet raim space required for n lod f introl (131.000 acre-feet) .Ian. 18, 1916 22.300 Jan. 20, 1916 45,300 35 Dec. 19. 1921 16.000 Dec. 25. 1921 25.000 19 Jan. 1, 1910 12.500 .Ian. 3. 1910 82.100 63 Feb. 20, 1914 11.800 Mar. 1. 1914 64.,500 49 Mar. 12, 1905 11.130 Mar. 14. 1905 87.100 66 Mar. 26, 1906 9.4.30 Mar. 29. 1906 29.100 22 Mar. 10, 1911 9.160 Mar. 14. 1911 71.400 54 Jan. 26, 1914 9.1.50 Jan. 27. 1914 911.200 76 Feb. 9, 1922 8.200 Feb. 13. 1922 68.(100 S3 Mar. 12. 1906 8.020 M:ir. 13. I'.Mm 88.900 68 Jan. 27. 1916 7,940 Jan. 30. r.illl 37.100 28 Feb. 7. 1909 7.100 Feb. 8. I'.m.i 118.100 90 Mar. 5. 1907 6.810 Mar. 11. r.Ml7 S.t.900 69 April 1. 1903 5.920 .\oril 2. 1903 95.400 73 Dec. 27, 1921 5.900 Dec. 29. 1921 12.700 10 Jan. 29. 1911 5.260 .Ian. 29. 1911 80.400 61 Jan. IH. 1914 .5.110 Jan. 18. 1914 103.000 79 Mar. 11. 1918 5.030 .Mar. U. 1918 21.E00 16 Jan. 10, I!K)7 4.670 Jan. 11. 1907 108.600 83 Jan. 31, 1911 4.220 Jan. 31, 1911 76.200 58 .\veragc 70.200 54 THE CONTROL OF FLOODS BY RESERVOIRS. 95 On the Mokehimne River, the large flood of January 30, 1911, would have been reduced from 20,600 second-feet to 5300 second-feet with 35,200 acre-feet of empty space in the reservoir to spare at the time the reservoir was nearest full. The average spare space at the times nearest full while controlling the twenty largest rain-water floods on the Mokelumne River would have been 42 per cent of the maximum required by the diagram. One small flood in the fall of 1909 would •have just filled the reservoir but there would have been more space than needed while controlling all other floods. On the San Joaquin River, the largest flood during the eighteen years of record (January 31, 1911) would have been reduced from a mean daily flow of 38,800 second-feet to 10,700 second-feet without the use of the top 14,200 acre-feet in the reservoir. The average unused space at the times the reservoir was nearest full while controlling all rain-w^ater floods would have been 36 per cent of the maximum space required by the diagram. There would have been space to spare while controlling all floods during the eighteen years of record except for two small floods barely larger than the controlled flow. One of these occurred before the opening date of the flood season, on October 2, 3918, and the other on April 6, 1911, the closing date of the flood season. All the snow-water floods of record on the San Joaquin River would have been controlled without the reservoir filling to within 21,100 acre-feet of the top. The average space to spare at the times nearest full while controlling snow-water floods would have been 53 per cent of the maximum required by the diagram. On the San Gabriel River, the large flood of January 18, 1916, would have been controlled without the use of the top 45,300 acre-feet of reservoir space. The nearest the reservoir would have filled while controlling all floods during the 30 years of record would have been to 12,700 acre-feet of a full reservoir. The average unused space at the times nearest full during the twent}^ largest floods of record would have been 54 per cent of the maximum required by the diagram. The full test of the four reservoir operating diagrams is expressed graphically on Plate XXII, ''Performance of Reservoir Operating Diagrams in Controlling Floods of Record." The ratio of the empty reservoir space provided by application of the diagrams to that actually necessary to control the remainder of the flood was computed for every day of stream-flow record on each of the four illustrative streams. The ratios on each stream were arranged in order of increasing magnitude and the number smaller than each successive size counted. These counts were increased by proportion to the number had the stream-flow records been 100 years in length. Assuming that the trend of these figures expresses the average relations of the future, these counts were plotted on Plate XXII to sliow the probable frequency witji which the empty space provided by application of the diagrams will approach the exact amount needed to secure the desired control. Plate XXII indicates that tlic Sacramento River diagram would probably provide, on the average, more than twice the empty reservoir space actually required on all days except 30 in each 100-year period, more than half again as much as needed on all days except 12 in each 100-year period and that its reservoir would probably fill to overflow- ing about one dav in each 80 vear.s. For the Mokelumne River dia WATER HEROTTRCES OF CAT.TFORNTA. PLATE XXII. 1 - '"^. 1 Rain water floods'' "•s. ^1^1 1 Itrt -^ c::. • — 1 -t — --H-4 0.1 100 0.1 100 • _ -- _ \, aximum controlled flow 1,900 sec ft. in "^ e «o i> — 1 — — O o 10 c \ V) \ m^ \ T3 \ ^ \ l_ O) E ■z. 100- =) V \ 1, > » ,, U - - e^ B td bd :^ 1 ll':i SAN JOAQUIN RIVER Near Friant _. Maximum controlled flow — . if 1 5n 3W water floods - 4,2 lOsec.ft^ oo(iofOct2,l9 aliO'O s! ■ i 1 li w 1.900 stcond fe fquircd 400 ac -10- ; I \ \ A J •» — -3|r— Ua n water floods TOO- " \ \ •« ^H -^ ; - ■ A ^-, Snow wter floods- ' 1 v.^_ H "* rr -::■■ = = I 10 100 0.1 I 10 Ratio of reservoir space provided to that actually' required. 100 Performance of Reservoir Operating Diagrams IN Controlling Floods of Record CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH RATIO OF RESERVOIR SPACE PROVIDED BY APPLICATION OF DIAGRAM TO THAT ACTUALLY REQUIRED FOR CONTROLUNG FLOODS OF RECORD IS SMALLER THAN INDICATED. THE CONTROL OF FLOODS BY RESERVOIRS. 97 gram, the indications are that probably more than twice the empty space actually needed would be provided on the average on all days except 100 in 100 years for rain-water floods and 50 in 100 years for snow^-water floods ; at least fifty per cent more than actually needed on all days except 60 in 100 years for rain-water floods and 24 in 100 years for snow-water floods ; and that the reservoir would fill to overflowing on two to three days in 100 years for both rain and snow-water floods. The indications for the San Joaquin River diagram are that, on the average, probably more than twice the empty space actually needed Avould be provided on all days except 70 in 100 years for rain-water floods and 150 in 100 years for snow-water floods; at least half again as much as needed on all days except 43 in 100 years for rain-water floods and 100 in 100 years for snow-water floods; and that the reser- voir would probably fill to overflowing on three days in 100 years for both rain and snow-water floods. For the San Gabriel River, the indications are that probably more than twice the empty space needed would be provided on all days except 120 in each 100-year period at least 50 per cent more than actually needed on all days except 50 in each 100 years, and that the reservoir would probably fill to overflowing on about one day in each 500 years. These tests agree fairly closely with the probability of exceptional behavior selected for construction of the diagrams. On the Sacramento, JMokelumne and San Joaquin rivers, by construction, the controlled flow for both rain and snow-water floods would be expected to be exceeded on an average of one day in 50 years. By test against the period of record the desired controlled flow of the Sacramento River diagram would probably be exceeded on an average of one day in 80 years and the Mokelumne and San Joaquin river diagrams on an average of one day in 30 to 40 years for both rain and snow-water floods. The desired controlled flow of the San Gabriel River diagram by construction would be expected to be exceeded on an average of one day in 1000 years. By test against the period of record the probable exceptional behavior of this diagram is one day in 500 years. 7—52411 98 WATER RESOURCES OF CALIFORNIA. CHAPTER VI. EFFECT ON CONSERVATION OF CONTROLLING FLOODS BY RESERVOIR OPERATING DIAGRAM. Effect determined by direct test. Four reservoir operating diagrams are described in chapter V, one for controlling floods on each of the four streams previously used to illustrate the characteristics of flood occurrence. These diagrams indi- cate the reservoir space for all conditions of prior rainfall, that should be empty on each day of the flood season in order to detain flow that may occur in excess of a specified maximum rate. Subsequent to the central date of the flood season, less empty space is required as the season progresses toward its close. The diagrams are constructed to release this reserved space as quickly as possible without sacrifice in the effectiveness of flood control. Therefore, until some analysis is developed that fits the characteristics of flood occurrence closer than the one herein described, it may be said that reservoir operation in accord with these diagrams secures the control of floods with a mini- mum interference with the use of the same space for conservation. To what extent, if any, the reservation of the varying amounts of space indicated on the diagrams may interfere with its use for conserva- tion is not apparent. The amount of the reservations relative to the volume of subsequent run-off determines this in each instance. There- fore, it is evident that the degree of flood control desired and the regi- men of the stream are important factors in determining the extent of interference, if any. Other factors are the size of the reservoir and the manner of its operation. If the total capacity of the reservoir were several times the largest reserve required for flood control, there would be many days on which the empty space due to normal operation for conservation would exceed that required for flood control. At such times there could be no interference with conservation by reason of the use of the same space for flood control. Therefore, the larger the total capacity of the reservoir in proportion to the maximum flood control reserve, the less is the opportunity for interference. Likewise the opportunity of interference is less, the greater the seasonal draw- down in the reservoir or the smaller the spring draft subsequent to the central date of the flood season during normal operation for conserva- tion. Because of the complication of these relations, the determination of the effect on conservation of controlling floods by the reservoir operating diagrams must be made through the analj'sis of each specific proposal. The interference or approach toward interference might well be different for each stream, each degree of flood control, and each size of reservoir and manner of operating it for conserving water. The succeeding pages of this chapter are devoted to the presentation of analyses of the effect on the water and power yield of combining flood control with several modes of operating four specific reservoirs, one on each of tlie illustrative streams. In these studies eacli reservoir is assumed to have been in existence at the beginning of continuous THE CONTROL OF FLOODS BY RESERVOIRS. 99 measurement of flow on its stream and to have been operated for con- servation in a specific manner through the entire period of stream flow record both with and without flood control. The effect on conservation in these instances of the use of the same space for both flood control and conservation is determined by a comparison of the yield of water and power in the two parallel sets of computations. In these computations the inflow, evaporation and drafts from the reservoirs are balanced daily and the new reservoir levels tabulated both with and without the reservation of space for flood control in accord with the operating diagrams. In doing this the daily values of the progressive rainfall indices are computed from rainfall records and the flood control feature applied just as though the reservoirs had been operated through these years according to the rules laid down by the reservoir operating diagrams. All conditions are held the same in the two parallel sets of computations except for the inclusion of the flood control feature in one set. Tables are included herein summarizing these computations and comparing the yields of water and power month by month and year by year through the entire period of run-off record. Graphical compari- sons are also included of the reservoir levels with and without flood control and of the stream flow below the dam, controlled, as well as that unimpaired by reservoir construction. Kennett Reservoir on Sacramento River. The ' ' Coordinated Plan ' ' * for development of the State 's waters presented to the 1927 session of the State Legislature proposes, among others, that a reservoir be constructed on the main Sacramento River with its dam near Kennett, about five miles below the confluence with the Pit River. The plan proposes that the dam be constructed to an initial height of 420 feet. This would impound 2,940,000 acre-feet of water. A power plant of 400,000 k. v. a. capacity would be constructed near the base of the dam. The "Coordinated Plan" is distinguished from other plans in that its reservoirs would be operated coordinately for several different purposes in a way to subserve the best interests of the State. The Kennett reservoir would be operated coordinately for the benefit of irrigation and domestic supply, navigation, salinity control, generation of power and the control of floods. During the first period of years while the demand for water is growing to meet its large yield, the Kennett reservoir would be operated to secure the most valuable power output while at the same time limiting floods to half the largest on record. In so doing, for a number of years to come, there would be adequate water in the discharge from the power plant for the needs of irrigation, domestic supply, navigation and for salt water control in all except extremely dry years. Later, the increased demand for water will require that the operation of the reservoir be changed over to yield the greatest volume of water equalized in accord with the irrigation demand while at the same time meeting the other needs. The genera- tion of power would become incidental to the yield of water. So • See Bui. No. 12, "Summary Report on the Water Resources of California and a Coordinated Plan for their Development," Division of Engineering and Irrigation, State Department of Public Works. 100 WATER RESOURCES OF CALIFORNIA. operated, the initial ln'iu;lii oi" dam would e(|ualize for irrigation use three-fifths of tiie mean annual run-oft" of the stream and produce on an average 35!), 400* kilowatts of electric energy. The yield of the Kennett reservoir in water and power for several heights of dam together with a full description of its uses is contained in Bulletin No. 15, "The Coordinated Plan of Water Development in the Sacramento Valley." The results of computations for several heights of dam are there tabulated. No special entries are included for navigation water nor for water for salinity control since their needs would be more or less coincident with the irrigation demand. They are regarded as part of this demand for estimating purposes. Like- wise, no special entries are made for domestic water supply because its volume would be relatively small. The effect of the inclusion of the flood control feature of the "Coordinated Plan" upon the yield of a reservoir with a 420-foot dam, the initial height proposed, is analyzed in the following pages. Plate XXIII, "Effect of Controlling Sacramento River Floods upon Stage of Kennett Reservoir," compares the reservoir stage day by day had it been in existence in the year 1895 and been operated continu- ously to January, 1926, as proposed in the "Coordinated Plan," with the stage had the flood control feature been omitted. This period of comparison is the extent of continuous records of stream flow on the Sacramento River. The comparison is delineated by lines extending across the plate in four rows. Each line represents a separate mode of operation. These lines fluctuate up and down and indicate bj' their vertical position the acre-feet of water in storage in the reservoir on each day of the thirty-year period under the several different modes of operation. The top guide line of each row represents a full reservoir and the bottom line an empty reservoir. The space between each pair of guide lines represents 200,000 acre-feet of capacity. The heavy black line extending across each row indicates the reservoir stage had the most valuable power output been generated as proposed in the first or temporary mode of operation under the "Coordinated Plan." A dash and dot black line indicates the stage had the greatest yield of irrigation water been obtained with electric power as an incidental product as proposed in the second or permanent mode of operation under the "Coordinated Plan. " These lines approx- imate operation as proposed by the "Coordinated Plan" except that the flood control feature is omitted. The reservoir stage resulting from the introduction of the flood control feature is delineated by red lines. The light red line indicates the stage had the reservoir been operated for flood control alone in accordance with the rule developed in the fore part of this volume and expressed on Plate XVIII, "Reservoir Operating Diagram for Con- ti-olling Floods on Sacramento River." p. 76. The heavy full red line indicates the departures in reservoir stage by reason of the inclusion of the flood control feature in the first or temporary mode of operation under the "Coordinated Plan." The light dash and dot red line indicates similarly the departures by reason of the inclusion of the flood control feature in the second or permanent mode of operation under the "Coordinated Plan." Where the light • Average for the 54-year period, 1871-1925. I902 HAY June: july aug. PLATE XXIII. LEGEND ol alone. (Mot shown where coincident with other red re incidental irrigation. Yield in power output 158,200 irrigation draft 1.631X00 ac ft per year (July draft 5.80 feenng and Irrigation, pa^e 63, for monthly distribution Jth Incidental power. Yield in irrigation draft 4,276.000 ac * 1( see 8ul. N? 6. Division of Engineering and Irrigation, pa|e ( Ltput 145,300 Kilowatts (average) with an installed cap. ((incidental irrigation, where affected by coordinatio Hth incidental power, where affected by coordination witt — ) .UFF 125,000 SEC. FT, bnio River near Red Bluff, taken from records of United P:?°° .^^^- '^^• River near Red Bluff, witti reservoir operated for irrigation -) and controlled (-r-v— ""v) minfall from July I up to successive dates in the season, to tj Hcords of United States Weather Bureau at Red Bluff. ENTO River Floods rilESERVOIR IGATION OR POWER DRAFT 100 FT. AC. FT PL ATE x\m ^,'TT!j3a>4 ^^ S^ = = = T-r -.J ;7< -^ - ^^"■■r -^'vf^- 1 1 i ifeii w £ ^ if' jv - : ; ] ^ ' I902 Si S -■ 1 z = z - 1 12: 3_0 - TP 5 ^ 1 s — 100 c 1 — 1 ' c ^^ lOOE i . ' / 5 P 5S CWITDIIM 1 3 o e_ s^ ^; 1 \ _/ Ustr.>mnayr.«nYII.L ¥^ -iL- N ^ -- " 1 ""' iClj -" -■! _i..r. - 1 - — zt ^ ' E; p fii^: ==^= ^. j "X ^s S 5^ 4- k- - = t= 5 ES 5 5 8~ - s - i s = I H i 3 m i t - ^ •v. r- z: 'J. r - sz = ''mt ZIZ i -| m ml 3 2 4, ^. M^ |^"n 1 7^ 92 5 i 4T'' - -i- - == 3 s r r.r.' ^ ^ = ^ = ^; 5; ^b. = s^ a t z = E z: P zl :^ S ^ ™ % s 1 Eh E: 5 too !?!L «.i^«, 1 1 1 L ' «. oirrBl|.y , ^4+ 1 1 -M—- ■:-t- ^^ -«,»^S. ».,.,.,<.,-. , . - <-. LfrtLI UH-UNIKULUNlj 3AUKAMLNI0 KIVLR rUUUUS mm hffr! ™=[ -L'--!^-^ --"- ^-=^4^ J7 SWi-lmli 7^ 7LX11 ir £ i r; - .'S ■? -" •: ~ iL A 1 •V ,r, :.'R."sa'' ! r„ '„ - : .„™ IF OPERATED PRIMARILY FOR DTHER IRRIGATION OR POWER ORftFT THE CONTROL OF FLOODS BY RESERVOIRS. 103 dash and dot red line coincides with the heavy full red line, both are "'^presented by a heavy dash and dot red line. Below the reservoir stage lines in each row are drafted to a special scale superimposed on the reservoir stage scale, a light black line showing the fluctuations of the stream flow unimpaired by reservoir storage and a light red line showing the stream flow as controlled by the second or permanent mode of operation under the "Coordinated Plan." Similarly, a black dotted line delineates the values of the progressive rainfall index that were used with the reservoir oper- ating diagram (Plate XVIII) in computing the stage of the reservoir with the flood control feature included. The greatest empty depth required for flood control during each season is noted on the graph in feet below full reservoir level. The largest is seen to be 21 of the 415 feet depth behind the dam when the reservoir is full. This was required during 13 of the 30 seasons. In 7 of the seasons there was no special lowering of the reservoir level for f 1 control since the empty space by reason of conservation operations was larger than required for flood control. The average amount of depression was about 11 feet, or 2.6 per cent, of the depth of a full reservoir at the dam. Of the entire elapsed time during the 30 seasons, the reservoir level would have had to be depressed especially for flood control only one-sixth of the time while operating primarily for power generation and one-eighth of the time while operating primarily for ^' 'igation. rhe effect of including the flood control feature of the ' ' Coordinated Plan" upon the reservoir stage resulting from conservation operations is seen to be small, yet very substantial reduction in flood volume is obtained. The largest flood of record occurred in February, 1909. It rtached a crest discharge of 278,000 second-feet. The flood control feature of the "Coordinated Plan" would have limited this flood to a discharge of 125,000 second-feet. Likewise the floods of ten other seasons of record that exceeded 125,000 second-feet would have been limited to this rate of discharge. The effect upon the water and power yield of the Kennett reservoir in securing this limitation to flood flows is disclosed by comparison of parallel sets of computations, one with and the other without the flood control feature of the "Coordinated Plan." These computations of yield were carried out as described in Bulletin No. 15, "The Coordi- nated Plan of Water Development in the Sacramento Valley," except that they were made on a daily instead of a monthly basis. The set of computations with the flood control feature included had to be made on a daily basis because the reservoir operating diagrams require a daily adjustment of reservoir stage during the flood season. There- fore, in order to make the two sets of computations exactly comparable, both were carried through the entire 30 years on a daily basis. The assumptions employed are listed on ])age 216 herein. The water yield (without deduction for prior rights downstream from the dam and with deficiencies in supply on an average of one year in ten) computed on a daily basis is identical with that of Bulletin No. 15 computed on a montlily basis excej^t that tlie deficiencies in per cent of a full supply are increased from 0.1 to 0.3 per cent in three out of the five deficient seasons. The power yield, however, is about 104 WATER RESOURCES OF CALIFORNIA. 3 per cent less when computed day by day rather than by monthly averages. It was 2.3 per cent less when operating primarily for power generation and 3.7 per cent less when power generation is incidental to irrigation use. This results from the assumption in the monthly com- putations that flow is available for power generation as an average monthly quantity instead of with the large daily fluctuations that some- times occur. At times when the reservoir is full, some of this water included in the monthly averages actually would have passed over the spillway instead of through the turbines. Therefore, the computations on a monthly basis show somewhat more water running through the power turbines than actually could have passed through them. The stream flow data employed in these computations are the esti- mated mean monthly discharges at the Kennett dam site with the entire flow of the Pit Kiver above Bieber deducted but without deduc- tion for prior rights downstream from the dam. These are published in Bulletin No. 15, "The Coordinated Plan of Water Development in the Sacramento Valley." For the purposes of computing the yield of the reservoir on a daily basis, these estimated monthly means were divided into daily discharges bearing the same relation to the corre- sponding daily flows measured at the Red Bluff gaging station as the estimated mean monthly flows at the Kennett dam site bear to the corresponding mean monthly flows measured at Red Bluff. Summaries are prepared of these computations comparing the water and power yield of the Kennett reservoir in tlie "Coordinated Plan," with and without the flood control feature. Those by years follow lierewith but those by months, because of their size, have been assem- bled in the last chapter of this volume. It may be observed upon reviewing these tables that the inclusion of the flood control feature of the "Coordinated Plan" has practically no effect upon the yield of the Kennett reservoir either in water or power. The water yield equalized for irrigation use, both with and without flood control, is identical either in the temporary or permanent mode of operating the reservoir. The power yield is 0.9 per cent less under the temporary and 0.2 per cent greater under the permanent mode of operation, all in the secondary output. These differences are very small and are discernible only because of the minute comparisons made to detect them. They are much smaller than the error contained in the usual computations of power output that are based on monthly averages of stream flow. The slightly less power output under the temporary mode of opera- tion when flood control is included, results from the extra water that may be run through the turbines while the reservoir level is depressed for flood control, being insufGcient at times to compensate for the slight reduction in power head. The table shows that this occurs at times during 16 of the 30 years. In 7 of the years the extra water available while the reservoir level is depressed for flood control is sufficient to develop a greater power output with flood control than without. In the remaining 7 years the reservoir stage is not affected by the inclusion of the flood control feature since the empty space, by reason of conservation operations, is at all times greater than needed for flood control. Under such circumstances the power yield with and without flood control is identical. The greatest difference in power THE CONTROL OF FLOODS BY RESERVOIRS. 105 yield witli and without flood control in any year of the 30 analyzed is 6.7 per cent. This occurred in 1900. The average reduction in power head by the inclusion of flood control is 2.0 feet. Under the permanent mode of operating the reservoir the power yield is greater with flood control than without because the extra volume of water that may be run through the turbines by reason of the inclusion of the flood control feature is more than sufficient to compensate for the small depression in head. The average reduction in power head that results from the depression of the reservoir level at times for flood control is 0.5 feet. An alternate rule for controlling floods by reservoirs. The rules for controlling floods by reservoirs described herein, grade with scientific nicety the flood control reserve in accord with the probable need for empty space to detain excess flood water. They were so constructed in order that the program of flood control evolved by the analysis would interfere as little as possible with conservation. It appears that, under some circumstances, this nicety of gradation in the amount of flood control reserve might be neglected without par- ticular detriment to the reservoir yields. By holding the maximum empty space ever required, in reserve throughout each flood season until its close instead of varying it during the season with the changing value of the progressive rainfall index, results could be obtained at the Kennett reservoir not greatly difi'erent from those secured by the appli- cation of the reservoir operating diagram. It is evident that such a rule would interfere with conservation very seriously under some circumstances, especially with a small reservoir. On the other hand, it is surprising how well it fits occurrences on the Sacramento River from 1895 to 1926 when applied to the size reservoir proposed at Kennett. The total reservoir capacity proposed at Kennett equals almost half the mean seasonal run-off and is about six times the maximum flood control reserve. In seasons of short run-off when it would seem that the nicety of gradation in the flood control reserve obtained by the operating diagram .should be particularly valuable, it is found generally that conservation draft holds the reservoir below the level of the maximum flood control reserve. At such times flood control by either rule does not depress the reservoir level. Hypotheti- cal seasons might be constructed in which this would not be so, however, the record of stream flow shows that none have occurred within the last thirty years. Should they occur, control by the reservoir operating diagram would interfere less with conservation than by the alternate rule. The water and power yield of the Kennett reservoir holding the maximum flood control reserve (454,000 acre-feet) empty throughout the sea.son (until April 8th) was computed in parallel to' that without flood control and to that with control by the reservoir operating dia- gram. The yearly and monthly summaries of these computations are included with the others in the adjoining tables. The reduction in yield from that without flood control is small. In the temporary mode of operation under the ''Coordinated Plan," the irrigation yield is identical but the primary power output is reduced 3.5 per cent. The secondar}' output, however, is increased 5.6 per cent so that the net 106 WATER RESOURCES OF CALIFORNIA. reduction in total power is 1.0 per cent. Under the permanent mode of operation, the average irrigation yield is reduced 0.3 per cent because of the larger deficiencies in seasons of short supply. In 1923 the deficiency is increased by 210,000 acre-feet, 5.0 per cent of the average seasonal yield. The incidental power* under the permanent mode of operation is reduced between 1 and 2 per cent.* • A fuU set of computations of the incidental power yield while operating pri- marily for irrigation was not completed. However, it is estimated the average power head would be reduced about 7.0 feet and 20,000 to 40,000 acre-feet more water would pass through the turbines. THE CONTROL OF FLOODS BY RESERVOIRS. 107 KENNETT RESERVOIR ON SACRAMENTO RIVER. Table of Yearly Summaries of Water and Power Yield Computed on a Daily Basis. Showing the effect of iuclusion of the flood control feature of the "Coordinated Plan." (See Chapter VIII for corresponding monthly summaries.) Table 1 — Operating primarily for power generation with incidental irrigation. With and without flood control by reservoir operating diagram. Table 2 — Operating primarily for irrigation with incidental power generation. With and without flood control by reservoir operating diagram. Table 3 — Operating primarily for irrigation. Comparison for two methods of flood control. Table 4 — Operating primarily for power generation with incidental irrigation. Comparison for two methods of flood control. Table 5 — Summary of power yield. With and without flood control by either of two methods. 108 WATER RESOURCES OF CALIFORNIA. TABLE 1. KENNETT RESER WATER AND POWER YIELD, OPERATING PRIMARILY BOTH WITH AND WITHOUT FLOOD CONTROL Yearly Summary of Computations (For corresponding monthly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Esti- mated run-off at Without flood control Stage of Power draft Average power yield Year reservoir through turbines in Waste Average n kilowatt site in acre-feet at acre-feet Evapora- over (Load factor= 0.75) beginning of year in acre-feet tion in acre-feet spillway in acre-feet power head in feet Primary Secondary •Primary Secondary Total 1896 8,306,000 2,256,000 3,205,000 1,968,000 78,000 2,491,000 400 113,000 69,500 182,500 1897 6.052,000 2,820,000 3,204,000 1 662,000 78,000 1,671,000 401 113,400 59,100 172,500 1898 3,308,000 2,257,000 3,218.000 21,000 75,000 392 113,400 700 114,100 1899 5.050,000 2,221,000 3,206,000 990,000 78,000 299.000 400 113,400 34.900 148.300 1900 5,720,000 2,698,000 3,193,000 1,537,000 78,000 1,081,000 402 113,400 54,200 167,600 1901 5,724,000 2,529,000 3,196,000 1,312,000 78,000 1,289,000 401 113,400 46,300 159,700 1902 8,685,000 2,378,000 3,201,000 1,659.000 78,000 3.185,000 400 113,400 58.900 172.300 1903 6,848,000 2,940,000 3,182,000 1,632,000 78,000 1,990,000 404 113,400 58.200 171.600 1904 10,378,000 2,906,000 3,204,000 2,437,000 78,000 5,144,000 400 113,000 85,600 198,600 1905 6,823,000 2,421,000 3,201,000 1,429,000 78,000 2,276,000 400 113,400 51,000 164.400 1906 7,981,000 2,257,000 3,212,000 1,807,000 78,000 2.673,000 399 113,100 63,900 177,300 1907 8,877,000 2,468,000 3,208,000 1,822,000 78,000 3,891,000 399 113,-tOO 64,500 177,900 1908 5,355.000 2,346,000 3,202,000 1,390,000 78,000 774,000 400 113,000 49,500 162,500 1909 10,871,000 2,257,000 3,203,000 2,116,000 78,000 5,053,000 400 113,400 74.800 188.200 1910 5,801.000 2.678,000 3,201,000 1,478,000 78,000 1.465,000 401 113,400 52,300 165,700 1911 6,383,000 2,257,000 3,212,000 1,446,000 78,000 1,655,000 398 113,400 51,500 164,900 1912 4,935,000 2,249,000 3,211,000 1,333,000 78,000 305,000 398 113,000 46.900 159,900 1913 5,017,000 2,257,000 3,201,000 1,189,000 78,000 253,000 400 113,400 42,100 155,500 1914 9,085,000 2,553,000 3,211,000 1,921,000 78,000 4,171,000 399 113,400 68,000 181,400 1915 9.454.000 2,257,000 3,214,000 1,853,000 78,000 4,094,000 398 113,400 65.500 178,900 1916 7,127,000 2,472,000 3,208,000 1,588,000 78,000 2,468,000 400 113,000 56,300 169,300 1917 4,705,000 2,257.000 3,215.000 897.000 78,000 515,000 397 113,400 32,000 145,400 1918 3,862,000 2,257,000 3,222,000 462,000 78,000 100,000 396 1 13,400 16,300 129,700 1919 5,306,000 2,257,000 3,211,000 905,000 78,000 1,185,000 399 113.400 32,400 145,800 1920 4,455,000 2,184,000 3,373,000 269,000 66,000 376 113,000 9,400 122,400 1921 6,255,000 2,931,000 3,199,000 1,447,000 78,000 2,139,000 400 113,400 51,600 165,000 1922 4,504.000 2.323,000 3,212,000 913,000 78,000 296,000 398 113,400 32,300 145,700 1923 3,294,000 2,328,000 3,223,000 133,000 78,000 398 113.400 4,600 118,000 1924 2,431,000 2,188,000 3,759,000 53,000 339 1 13,000 113,000 1925 5,420,000 188,012,000 807,000 3,361,000 337,000 78,000 211,000 381 113,400 12.100 125.500 Total 97.101,000 37,953,000 2,300,000 50,674,000 Average 6,267.000 3,230,000 1,265,000 77,000 1.689,000 395.8 113,400 44,800 158,200 Total primiry powpr production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 109 VOIR ON SACRAMENTO RIVER. FOR POWER GENERATION WITH INCIDENTAL IRRIGATION BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table la, page 218.) Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum coDtrolled flow at Red Bluff 1 25,000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Stage of reservoir at beginning Power draft through turbines in acre-feet Evapora- tion in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Average power head in feet Average power yield in kilowatts (Load factor=0.75) Year of year in acre-feet Primary Secondary *Priinary Secondary Total 2,256,000 2,595,000 2,257,000 2,221,000 2,588,000 2,529,000 2,378,000 2,652,000 2,601,000 2,421,000 2,257,000 2,468,000 2,346,000 2,257,000 2.637,000 2,257,000 2,249,000 2,257.000 2,553,000 2,257,000 2.472.000 2.257.000 2,257.000 2,257.000 2,184,000 2,727,000 2,323,000 2,328,000 2,188,000 807,000 3,225,000 3,227,000 3,248,000 3,209,000 3,214,000 3,221,000 3.214,000 3,210.000 3,238.000 3,217,000 3,224,000 3,230,000 3.226,000 3,217,000 3.210.000 3.228.000 3.211,000 3,216,000 3,221,000 3,224,000 3,236,000 3,220,000 3,222.000 3.223,000 3,374.000 3.218.000 3,215,000 3.223,000 3,759.000 3,361,000 1.701,000 1,552,000 21,000 994,000 1,238.000 1.174.000 1.569.000 1.647.000 2,449,000 1.504,000 1,849,000 2,042,000 1,146,000 2,099,000 1,443,000 1,443,000 1.333.000 1,093.000 1.914.000 1.964.000 1,704.000 770.000 462.000 1,020,000 270.000 1,391,000 832.000 133,000 337,000 78,000 78,000 75.000 78.000 78,000 78,000 78,000 78.000 78,000 78,000 78,000 78 000 78,000 78,000 78,000 78,000 78,000 78,000 78.000 78.000 78.000 78.000 78.000 78,000 66,000 78,000 78.000 78.000 53,000 78,000 1,640,000 1,175,000 388,000 1,228,000 1,402,000 2,936,000 1,834 000 3.592.000 1,903.000 1.780,000 3,044,000 930,000 4,785,000 1,036.000 1,217,000 137,000 3,358,000 2,509,000 2,149,000 178,000 919,000 202,000 1,936.000 136,000 1,323,000 358,000 14,000 21,000 614.000 130,000 1,201,000 285,000 839,000 605.000 64.000 312.000 414,000 425,000 305,000 197,000 810,000 1,464,000 175,000 459,000 100,000 139,000 36,000 238,000 211,000 398 396 392 399 398 397 398 399 395 397 397 395 398 397 399 396 398 398 397 396 396 397 396 396 375 397 398 398 339 381 113,000 113,400 113,400 113,400 113,400 113,400 113,400 113 400 113,000 113,400 113,400 113,400 113,000 113,400 113,400 113.400 113,000 113,400 113,400 113,400 113,000 113,400 113,400 113,400 113,000 113,400 113,400 113,400 113,000 113,400 59,700 54,300 700 35,000 42,900 40,400 55,300 57,800 85.100 53.100 65.100 71,400 40,200 73,600 50,800 50,800 46,900 38,500 67,400 69,000 59,500 27,400 16,300 36,000 9,400 48,900 29,400 4,600 12,100 172,700 167,700 114,100 148,400 156,300 153,800 168,700 171,200 198,100 166,500 178,500 184,800 153,200 187,000 164,200 164,200 159,900 151,900 180,800 182,400 172,500 140,800 129.700 149,400 122,400 162,300 142,800 118,000 113.000 125,500 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 97,481,000 3,249.000 37,094.000 1,236.000 2,300,000 77,000 40,414,000 1,347,000 10,739,000 358,000 393.8 113,400 43,400 156,800 Total Average 110 WATER RESOURCES OF CALIFORNIA. TABLE 2. KENNETT RESER WATER AND POWER YIELD, OPERATING PRIMARILY BOTH WITH AND WITHOUT FLOOD CONTROL Yearly Summary of Computations (For corresponding monthly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. , Without flood control Irrigation Estimated Stage of drjftin Power draft througli turbines Deficiency Average Average Year run-off reservoir acre-feet Waste power power at dam at (no Evapora- over in head yield in site in beginning deduction tion in spillway irrigation supply through kilowatts acre-feet of for down- acre-feet in period of (Load year in acre-feet stream prior rigiits) in acre-feet acre-feet in acre-feet operation in feet factor^ 1.00) 1896 8,306,000 1,860,000 4,276,000 65,000 5,286,000 1,678.000 375 178,400 1807 6,052,000 2,586,000 4,276,000 59,000 5,531,000 1,172,000 359 180,800 1898 3,308,000 1,408,000 4,189,000 43,000 3,149,000 87,000 342 91,200 1899 5,050,000 484,000 4,123,000 39,000 3,130,000 153,000 329 88,700 1900 5,720,000 1,372,000 4,276,000 55,000 4,723,000 327,000 337 145,500 1901 5,724,000 1,534,000 4,276,000 54,000 4,721,000 759,000 336 144.900 1902 8,685,000 1,268,000 4,276,000 61,000 5,051,000 1,919,000 361 166.300 1903 6,848,000 2,432,000 4,276,000 54,000 5.545,000 1,350,000 347 176,700 1904 10.378,000 1,872.000 4.276,000 65,000 5,055 000 4,108,000 372 170,200 1905 6,823,000 2,462,000 4,276,000 59,000 5,727,000 1.822,000 361 188,300 1906 7,981,000 1,206,000 4,276,000 69,000 4,713,000 1,491,000 378 161,500 1907 8,877,000 2,309,000 4.276,000 65,000 5,553,000 3,257,000 369 186,200 1908 5,355,000 1,795,000 4,276,000 58,000 5,170.000 302,000 353 166,000 1909 10,871,000 1,155,000 4,276.000 59,000 5,723,000 3,543,000 362 190,400 1910 5,801,000 2,216,000 4,276,000 55,000 5,383,000 911,000 347 171,100 1911 6,383,000 1,215,000 4,276,000 63,000 4,709,000 868,000 362 155,500 1912 4,935,000 1,447,000 4.276,000 61,000 4,032,000 83,000 360 130,200 1913 5,017,000 1,709,000 4,276,000 58,000 4,537,000 58,000 348 143,800 1914 9,085,000 1.611,000 4,276.000 65,000 5.729.000 2,744,000 370 192,800 1915 9,454,000 1.631,000 4,276,000 66,000 5,341,000 2,972,000 374 181.100 1916 7,127,000 2,138,000 4,276.000 59.000 5.627,000 1,798,000 358 183.300 •,917 4,705,000 1,321,000 4.276.000 59,000 4,124,000 236.000 348 129.700 1918 3,862,000 1.132,000 4.276,000 50,000 3,158,000 354 96.400 1919 5,306,000 668,000 4,276,000 54,000 1,533,000 215,000 334 138.500 1920 4,455,000 719,000 3.121,000 24.000 1.970.000 1,155,000 315 53,400 1921 6,255,000 2,029,000 4.276.000 56,000 5.514,000 1,186,000 350 176,800 1922 4.504,000 1.059.000 4.276.000 56.000 3,801,000 342 116.700 1923 3,294,000 1,426.000 4.101.000 43,000 3,134,000 175,000 341 91.100 1924 2,431,000 376.000 2,136,000 13,000 1,072,000 2,140,000 283 25.600 1925 5,420,000 658.000 4,276,000 54,000 4,353,000 297,000 352 135.500 Total 188,012.000 124,570.000 1,641,000 136,102,000 33.096,000 3,710,000 Average 6,267,000 4,152,000 55,000 4,.537.000 1,103,000 124.000 353. 4 145,300 THE CONTROL OF FLOODS BY RESERVOmS. Ill VOIR ON SACRAMENTO RIVER. FOR IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 2a, page 234.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram 1 Maximum controUed flow at Red Bluff 125,000 sec.-f t. Maximum reservoir space re quired 454,000 ac.-ft. Irrigation Stage of reservoir at l)eginning of year in acre-feet draft in acre-feet (no deduction for down- stream prior rights) Evapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor— 1.00) Year 1,860,000 4,276.000 65,000 4,901,000 1,148.000 915,000 373 164,000 1896 2,586,000 4,276,000 59,000 5,616,000 916,000 171,000 358 181,900 1897 1.408,000 4,189,000 43,000 3,149,000 87,000 342 91,200 1898 484,000 4,123,000 39,000 3,130.000 153,000 329 88,700 1899 1.372,000 4,276,000 55,000 4,745,000 305,000 342 145,300 1900 1.534,000 4,276,000 54,000 4,670,000 810,000 337 142,000 1901 1,268,000 4,276,000 61,000 4,949,000 1,682,000 339,000 359 161,600 1902 2,432,000 4,276,000 54,000 5,722,000 1,149,000 24,000 345 181,000 1903 1,872,000 4.276,000 65,000 5,152,000 3.170,000 841,000 370 172.600 1904 2,462,000 4.276,000 59,000 5,908,000 1,550,000 91,000 359 193,300 1905 1,206,000 4,276,000 69,000 4,798,000 1.100,000 .306.000 377 163,700 1906 2,309,000 4.276,000 65,000 j 5,989,000 2.468.000 352,000 366 199,700 1907 1,795,000 4,276,000 58,000 4,919,000 553,000 352 155,900 1908 1,155,000 4,276,000 59,000 : 5,648,000 , 3,524.000 94.000 363 186,400 1909 2.216,000 4.276.000 55,000 5,369,000 708.000 217,000 347 170,100 1910 1,215,000 4,276.000 63.000 4,952,000 481,000 144,000 363 163.400 1911 1,447,000 4,276,000 61,000 4,032,000 83,000 360 130,200 1912 1,709,000 4.276.000 58,000 4,533.000 1 10.000 5-',0;i0 352 143.600 1913 1,611,000 4.276,000 65,000 5,761,000 2,214,000 498,000 369 192,900 1914 1,631,000 4,276,000 66,000 5,390,000 1,896,000 1,027,000 372 181,900 1915 2,138,000 4,276,000 59,000 5.790,000 1,598,000 37,000 355 187,200 1916 1,321,000 4.276.000 59,000 4,124,000 235,000 348 129,700 1917 1.132,000 4,276,000 50,000 3,158,000 354 96,400 1918 668,000 4,276,000 54,000 4,665,000 48,000 35,000 332 142,900 1919 719,000 i 3.121,000 24,000 1,979.000 ; 1,155,000 315 53,400 1920 2,029,000 4,276,000 56,000 5,608,000 1,092,000 348 178,700 1921 1,0.59,000 4,276.000 56,000 3,801,000 342 116,700 1922 1.226,000 4,101,000 43,000 3,134.000 175,000 341 91,100 1923 376,000 2,136,000 13,000 1,072,000 2,140,000 283 25.600 1924 658,000 4,276,000 54,000 4.318,000 152,000 180.000 1 352 133,900 1925 124,570,000 1,641,000 136,982,000 26,574,000 5,642,000 3,710.000 1 Total 4,152,000 55,000 4,566,000 1 886,000 188,000 124,000 352.9 [ 145,600 Average 112 WATER RESOURCES OF CALIFORNIA. TABLE 3. KENNETT RESER COMPARISON OF WATER YIELD FOR TWO METHODS OF Yearly Summary of Computations (For corresponding monthly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125.000 sec.-ft. Estimated nin-off at dam site in acre-feet Maximum reservoir space required 454,000 ac.-ft. Year Stage of reservoir at beginning of year in acre-feet Irrigation draft in acre-feet (no deduction for downstrean Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficienc}' in irrigation supply in acre-feet prior rights) 1896 8,306,000 1,860,000 4,276.000 65,000 1,767,000 1,472,000 1897 6,052.000 2,586,000 4.276,000 59,000 2,413,000 482,000 1898 3,308,000 1.408.000 4.189.000 43,000 87,000 1899 5,050.000 484.000 4.123.000 39,000 153.000 1900 5,720,000 1,372.000 4,276,000 55,000 1,053,000 174,000 1901 5,724,000 1.534.000 4.276,000 54.000 1,635,000 25.000 1902 8,685,000 1,268,000 4,276,000 61,000 2,507,000 677.000 1903 6,848,000 2,432,000 4,276,000 54,000 2,773.000 305.000 1904 10,378,000 1,872,000 4,276,000 65,000 4,264,000 1.183,000 1905 6.823,000 2,462,000 4,276,000 59.000 3,278,000 466,000 1906 7.981,000 1,206,000 4,276,000 69,000 1.887,000 616,000 1907 8,877.000 2.309.000 4,276.000 65,000 4.385.000 665,000 1908 5,355,000 1.795.000 4,276,000 58,000 1.401.000 260.000 1909 10,871,000 1,155.000 4,276,000 59,000 5,001.000 474,000 1910 5,801.000 2,216,000 4,276,000 55,000 1,586,000 885,000 1911 6,383,000 1,215,000 4,276,000 63,000 1,357,000 455,000 1912 4,935,000 1,447,000 4.276.000 61.000 336,000 1913 5,017,000 1,709,000 4,276,000 58.000 172,000 609,000 1914 9,085,000 1,611.000 4,276,000 65.000 3,843,000 881.000 1915 9,454,000 1.631.000 4,276,000 66,000 3,165.000 1,440,000 1916 7.127,000 2.138.000 4,276,000 59,000 3,223,000 386.000 1917 4.705 000 1.321,000 4,276,000 59,000 559.000 1918 3,862,000 1.132.000 4,276,000 50,000 1919 5.306.000 668,000 4,276,000 54.000 591,000 334,000 1920 4,455,000 719,000 3,121,000 24,000 1.155.000 1921 6,255.000 2,029,000 4,276,000 56,000 2,682,000 211.000 1922 4,504,000 1,059,000 4.276,000 56,000 5.000 1923 3,294.000 1,226.000 4,101,000 43,000 175,000 1924 2431.000 376,000 2,136,000 13,000 2,140.000 1925 5.420,000 658,000 4,276,000 54,000 526,000 487.000 Total 188,012,000 124,570,000 1,641,000 49,509,000 13.417.000 3,710,000 Average 6,267,000 4,152,000 55,000 1,650,000 •147,000 124,000 THE CONTROL OF FLOODS BY RESERVOIRS. 113 VOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 3a, page 250.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of reservoir at beginning of year in acre-feet Irrigation draft in acre-feet Evaporation Release through flood Waste over spillway in acre-feet Deficiency in irrigition Year (no deduction for downstream prior rights) in acre-feet control outlets in acre-feet supply in acre-feet 1,860,000 4,276,000 65,000 2,760,000 579,000 1896 2,486,000 4,276,000 59,000 2,747,000 48,000 1897 1.408,000 4,184,000 43,000 5,000 92,000 1898 484.000 4,123,000 39,000 153,000 1899 1,372,000 4,276,000 47,000 1,506,000 1900 1,263,000 • 4,268,000 44,000 1,727,000 8,000 1901 948,000 4,276,000 61,000 2,705,000 159,000 1902 2,432.000 4,276,000 53,000 3,206,000 1903 1,745,000 4,270,000 65,000 4,634,000 686,000 1904 2,462,000 4,276,000 57,000 3,862,000 1905 1,090,000 4,276,000 69,000 2,253,000 164,000 1906 2,309,000 4,276,000 65,000 4,792,000 258,000 1907 1,795.000 4.276,000 54,000 1.867,000 1908 953,000 4,276,000 59,000 5,331.000 1909 2.158,000 4,276,000 53,000 2,556,000 1910 1,074,000 4,276,000 63,000 1,634,000 37,000 1911 1,447,000 4,276,000 59,000 511,000 1912 1,536,000 4,276,000 55,000 734,000 1913 1,488,000 4,276,000 65,000 4,337,000 264.000 1914 1.631.000 4,276,000 66,000 3,894,000 711,000 1915 2,138,000 4,276,000 55,000 3,735,000 1916 1,199,000 4,276,000 59,000 323,000 114,000 1917 1,132 000 4,248,000 45,000 110.000 28,000 1918 591,000 4,276,000 51,000 948,000 1919 622,000 3,026,000 22,000 1,250,000 1920 2,029,000 4,276,000 51,000 3,119,000 1921 838,000 4,276,000 53,000 2.000 1922 1,011,000 3,891,000 38,000 385,000 1923 376,000 2,136.000 13,000 2,140,000 1924 658,000 4,276,000 54,000 959,000 54,000 1925 124,224,000 1,582,000 60.257,000 3,074.000 4,056,000 Total 4,141,000 53,000 2,009,000 102,000 135,000 Average 114 WATER RESOURCES OF CALIFORNIA. TABLE 4. KENNETT RESER COMPARISON OF WATER AND POWER YIELD, OPERATING PRIMARILY TWO METHODS OF Yearly Summary of Computations (For corresponding monthly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 12r,000 sec .-ft. Esti- Maximum reserve space required 454,000 ac.-ft. mated run-off Year at Stage of Power draft Release Average power yield dam reservoir through turbines in through Waste Average in kilowatts site at acre-feet Evapora- flood over (Load factor=0.75) in acre-feet beginning tion in acre-feet control outlets spillway in power head in feet of year in acre-feet Primary S;cond- ary in acre-feet acre-feet •Primary .Second- ary Total 1896 8,306,000 2,256,000 3,225,000 1,701,000 78,000 1,640,0001 1,323,000 398 113,000 59,700 172,700 1897 6,052,000 2,595,000 3,227,000 1,552,000 78,0001 1,175,0001 358,000 396 113,400 54,300 167,700 1898 3,308,000 2.257,000 3,248.000 21.000 75.000: 0' 392 113,400 700 114,100 1899 5,050.000, 2,221.000 3,209,000 994.000 78,0001 388,000! 14.000 399 113,400 35,000 148,400 1900 5,720,000 2,088,000! .3,214.000 1,238,000 78,0001 1.228.000! 21,0001 398 113,400 42,900 156,300 1901 5,724,000 2,529,000 3.221,000 1,174,000 78.000 1,402,0001 397 113,400 40,400 1.53,800 1902 8.685,0001 2,378.0001 3,214,000 1,569,000 78.000J 2,936,0001 614,000| 398 113,400 55,300 168.700 1903 6,848,000, 2,652.000! 3.210.000 1,647,000 78,000 1. 834.0001 130,000! 399 113,400 57,800 171,200 1904 10,378,000 2,601,000' 3.238,000 2,449,000 78,000; 3,592,090 1,201,000| 395 113,000 85,100 198.100 1905 8,823,000 2,421,000 3,217,000 1,504,000 78,000 1,903,000, 285,000 397 113,400 53,100 166,500 1906 7,981,000 2,257,000 3,224,000 1,849,000 78,000l 1,780,000! 839,000 397 113,400 65,100 178,500 1907 8,877,000 2,468,000 3,230,000 2,042,000 78,000 3,044,0001 605,000 395 113.400 71,400 184.800 1908 5,355,000! 2,346,000 3,226,000 1.146,000 78,000 930,000 64,000 398 113,000 40,200 153,200 1909 10,871,000 2,257,000 3,217,000 2,099,000 78.000 4.785.000 312,000 397 113,400 73.600 187,000 1910 5,801,000 2,637,000 3,210,000 1,443.000 78.000! 1.036.000 414,000 399 113,400 50.800 164.200 1911 6,383,000 2,257,000 3.228,000 1,443,000 78.0001 1,217,000 425,000 396 113,400 50,800 164.200 1912 4,935,000 2,249,000 3,211,000 1.333.000 78.000; 305,000 398 113,000 40,900 15,1.900 1913 5,017,000' 2,257,000 3,216,000 1.093,000 78.000! 137,000 197,000 398 113,400 38,500 151.900 1914 9,085,000; 2,553,000 3,221,000 1,914,000 78,000! 3,358,000 810,000 397 113,400 67,400 180.800 1915 9,454,000, 2,257,000 3,224,000 1,964,000 78,000 2,509,0001 1,464.000 396 113,400 69,000 182.400 1916 7,127,000' 2,472.000 3,236,000 1,704,000 78,000 2,149,900 175,000 396 113,000 59,500 172,500 1917 4,705,000! 2,257,000 3,220,000 770,000 78,000 178,000 459,000 397 113,400 27,400 140,800 1918 3,862,000 2.257,000 3,222,000 462,000 78,000 100,000 396 113,400 16,300 129,700 1919 5,306,000 2,257,000 3,223,000 1,020,000 78,000 919,000 139,000 396 113,400 36,000 149,400 1920 4,455,000 2.184,000 3.374.000 270,000 66,000 202,000 375 113,000 9,400 122,400 1921 6,255,000: 2,727,000 3.218,000 1,391,000 78.000 1,936,000 36.000 397 113,400 48,900 162,300 1922 4,504,000: 2,323,000 3,215,000 832,000 78,000 136,000 238,000 398 113,400 29,400 142,800 1923 3,294,000, 2,328,000 3,223,000 133,000 78,000 398 113,400 4,600 118,000 1924 2,431,000 2,188,000 3,759,000 53,000 339 113,000 113,000 1925 5,420,000, 807.000| 3,361,000 337,000 78.000 211.000 381 113,400 12.100 125.500 Total 188,012.000 97,481,000 37,094,000 2.300,000'40.414,000 10,739,000 Average 6.267,000 3.249,000 1,238,000 77,000 1,347,000 358,000 393.8 113.400 43.400 156,800 •Total primary power production in February of leap years taken the same as in other years THE CONTROL OF FLOODS BY RESERVOIRS. 115 VOIR ON SACRAMENTO RIVER. FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FOR FLOOD CONTROL. Carried out on a Daily Basis. many, see Table 4a, page 26b.) Installed capacity of power plant 400,000 k.v.a. P.F. = 0.80. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) In reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Power draft Release Average power yield Year reservoir through turbines in through Waste Average in kilowatts at acre-feet Evapora- flood over (Load factor^ =0.75) beginning tion in acre-feet control outlets spillway in power head in feet of year in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 2,075,000 3,149,000 2,102,000 76,000 1,800,000 768,000 392 109,100 73,000 182,100 1896 2,486,000 3,149,000 1,933,000 75,000 1,306,000 391 109,400 67,100 176,500 1897 2,075,000 3,190,000 46,000 72,000 384 109,400 1,500 110,900 1898 2,075,000 3,149,000 887,000 73,000 541,000 390 109,400 30,400 139,800 1899 2,475,000 3,146,000 1,373,000 74,000 1,222,000 391 109,400 47,100 156,500 1900 2,380.000 3,154,000 1,270,000 73,000 1,356,000 389 109,400 43,400 152,800 1901 2,251,000 3,143,000 1,853,000 75,000 3,194,000 185,000 391 109,400 64,500 173,900 1902 2,486,000 3,140,000 1,567,000 74,000 2.089,000 392 109,400 54,100 163,500 1903 2,464,000 3,155,000 2,679,000 77,000 3,930,000 764,000 391 109,100 92.300 201,400 1904 2,237.000 3,157,000 1,525,000 74,000 2,229,000 390 109,400 52,800 162,200 1905 2,075,000 3,144,000 2,131,000 77,000 1,914.000 465,000 391 109,400 74,100 183,500 1906 2,325,000 3,147,000 2,264,000 76,000 3,307,000 233,000 391 109,400 78,500 187,900 1907 2,175,000 3,164,000 1,339,000 74,000 878,000 390 109,100 46,200 155,300 1908 2,075,000 3,153,000 2,202,000 75,000 5,055,000 390 109,400 76,100 185,500 1909 2,461,000 3,151,000 1,575,000 74,000 1,387,000 390 109,400 54,100 163,500 1910 2,075,000 3,157,000 1,699,000 75,000 1,378,000 74,000 390 109,400 59,300 168,700 1911 2,075,000 3,161,000 1,577,000 75,000 120,000 390 109,100 54,500 163,600 1912 2,077,000 3,152,000 1.388,000 74,000 91,000 390 109,400 48,000 157,400 1913 2,389.000 3,147,000 2,209,000 76,000 3,695,000 272,000 390 109,400 76,500 185,900 1914 2,075,000 3,147,000 2,087,000 76,000 3,042,000 834,000 391 109,400 72,400 181,800 1915 2,343,000 3,164,000 1,695,000 74,000 2,462,000 389 109,100 58,300 167,400 1910 2,075,000 3,158,000 1,188,000 75,000 227,000 57,000 389 109,400 41,700 151,100 1917 2,075,000 3,168,000 409,000 74,900 211,000 387 109,400 14,000 123,400 1918 2,075,000 3,156,000 835,000 74,000 1,245,000 389 109,400 29,000 138,400 1919 2,071,000 3,290,000 192,000 66,000 492,000 371 109,100 6,500 115,600 1920 2,486,000 3,154,000 1,309,000 74,000 2,043,000 390 109,400 45,100 154,500 1921 2,161,000 3,1,59,000 981,000 74,000 296,000 389 109,400 33,900 143,300 1922 2,155,000 3,152,000 71,000 74,000 77,000 390 109,400 2,500 111,900 1923 2,075,000 3,692,000 53,000 334 109,100 109,100 1924 761,000 3,290,000 594,000 75,000 147,000 375 109,400 20,900 130,300 1925 95,438,000 40,980,000 2,208,000 45,734,000 3,652,000 Total 3,181,000 1,366,000 74,000 1,524,000 122,000 386.9 109,400 47,300 156,700 Average 116 WATER RESOURCES OP CALIFORNIA. TABLE 5. KENNETT RESER SUMMARY OF POWER BOTH WITH AND WITHOUT Summary of Tables (For corresponding monthly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigation Average power yield in kilowatts (Load factor^O.75) Year Without flood control Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Maximum reservoir space required 454.000 acre-feet With flood control, holding maximum reservoir space required (454,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft •Primary Secondary Total •Primary Secondary Total •Primary Secondary Total 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1 13.000 113,400 113,400 113,400 113.400 113.400 113.400 113,400 113,000 113,400 113,400 113.400 113,000 113,400 113,400 1 13,400 113,000 113,400 113,400 113.400 113.000 113,400 113,400 1 13,400 113,000 113,400 113,400 113,400 113,000 113,400 69,500 59,100 700 34,900 54,200 46,300 58,900 58,200 85,600 51,000 63,900 64,500 49.500 74,800 52,300 51,500 46,900 42,100 68,000 65,500 56,300 32.000 16.300 32,400 9,400 51,600 32,300 4,600 12,100 182,500 172,500 114.100 148,300 167,600 159,700 172,300 171,600 198,600 164,400 177.300 177.900 162,500 188.200 165,700 164,900 159,900 155,500 181,400 178,900 169,300 145,400 129,700 145,800 122,400 165,000 145,700 118,000 113,000 125.500 113,000 113,400 113.400 113.400 113,400 113.400 113.400 113,400 113,000 113.400 113,400 113,400 113,000 113,400 1 13,400 113.400 113.000 113.400 113,400 113,400 1 13,000 113,400 113,400 113,400 113.000 113,400 113,400 113,400 113,000 113,400 59.700 54.300 700 35.000 42.900 40.400 55.300 57.800 85,100 53,100 65,100 71.400 40 200 73,600 50,800 50,800 46,900 38,500 67,400 69.000 59.500 27,400 16,300 36,000 9,400 48.900 29,400 4,600 12,100 172,700 167.700 114,100 148.400 156.300 153,800 168,700 171,200 198.100 166,500 178 500 184,800 153,200 187,000 1M,200 164,200 159,900 151,900 180,800 182,400 172,500 140,800 129,700 149,400 122,400 162,300 142,800 118,000 113,000 125,500 109,100 109,400 109,400 109,400 109,400 109,400 109,400 109,400 109,100 109,400 109,400 109,400 109.100 109,400 109,100 109,400 109,100 109,400 109,400 109,400 109,100 109,400 109,400 109,400 109,100 109,'<00 109,400 109,400 109,100 109,400 73,000 67,100 1,500 30,400 47 100 43,400 64,500 54,100 92,300 52,800 74,100 78.500 46.200 76.100 54.100 59.300 54.500 48,000 76.500 72,400 58,300 41,700 14,000 29,000 6,500 45,100 33,900 2,500 20,900 182,100 176,500 110,900 139,800 156 500 152,800 173,900 163,500 201.400 162,200 183 500 187,900 155,300 185,500 163,500 168.700 163,600 157,400 185,900 181,800 167.400 151.100 123.400 138,400 115.600 154,500 143.300 111.900 109.100 130.300 Average 113,400 44,800 158,200 113,400 43,400 156,800 109,400 47,300 156,700 •Total primary power production of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 117 VOIR ON SACRAMENTO RIVER. YIELD BY YEARS FLOOD CONTROL. 1, 2, and 4. mary, see Table 5a, page 282.) Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Operating primarily for irrigation with incidental power generation Seasonal irrigation yield 4,276,000 ac.-ft. (Deficiency in supply one year in ten. !> deduction for downstream prior rights) Average power yield in kilowatts (Load factor=1.00) Coordinated mth flood control by reservoir operating diagram Year Without flood control Maximum controlled flow at Red Bluff 125,000 sec.-ft. Maximum reservoir space required 454,000 acre-feet Primary Secondary Total Primary Secondary Total 178.400 178,400 164,000 164,000 1896 180,800 180,800 181,900 181,900 1897 91.200 91,200 91,200 91.200 1898 88,700 88,700 88,700 88,700 1899 145,500 145,500 145,300 145,300 1900 144,900 144,900 142.000 142,000 1901 166,300 166,300 161,600 161,600 1902 176,700 176,700 181.000 181,000 1903 170,200 170,200 172,600 172,600 1904 188,300 188,300 193.300 193,300 1905 161.500 161,500 163,700 163,700 1906 186,200 186,200 199,700 199,700 1907 166,000 166,000 155,900 155,900 1908 190,400 190,400 186,400 186,400 1909 171,100 171,100 170,100 170,100 1910 155,500 155,500 163,400 163,400 1911 130,200 130,200 130,200 130,200 1912 143,800 143,800 143,600 143,600 1913 192,800 192,800 192,900 192.900 1914 181,100 181.100 181,900 181.900 1915 183,300 183,300 187,200 187,200 1916 129.700 129.700 129,700 129.700 1917 96,400 96.400 96,400 96,400 1918 138,500 138,500 142,900 142,900 1919 53,400 53,400 u 53,400 53,400 1920 176,800 176,800 178,700 178,700 1921 116,700 116,700 116,700 116.700 1922 91.100 91,100 u 91,100 91,100 1923 25,600 25.600 25,600 25,600 1924 135,500 135,500 133.900 133,900 1925 145,300 145,300 145,600 145,600 Average 118 WATER RESOURCES OF CALIFORNIA. Pardee Reservoir on Mokelumne River. The East Bay Munieii)al Utility District proposes to construct the Pardee reservoir of 222,000 acre-feet capacity at tiie site on the Mokel- umne River known by many as the Lancha Plana. It is estimated that this reservoir will yield 200 million gallons per day equalized for municipal supply. The dam would be 345 feet high. A power plant of 15,000 k.w. capacity at its base would generate electricity with the water passing by the dam. The effect of including in the plans of the East Bay Municipal Utility District a flood control feature similar to that devised for the reservoirs of the "Coordinated Plan" was investi- gated by the Division of Engineering and Irrigation under agreement with the district of date February 5, 1926. The size of floods to be controlled on the Mokelumne River is indi- cated by the largest ones in the stream flow records. The largest rain- water flood in the twenty-one years of measured flow occurred on January 30, 1911, with a crest discharge of 20,600* second-feet. The largest snow-water flood occurred on June 12, 1906, with a discharge of 8740 second-feet. The crest discharge of these floods could be lim- ited by the Pardee reservoir through the use of a diagram like that on Plate XIX, "Reservoir Operating Diagram for Controlling Floods on IMokelumne River" (p. 80), to 5300 second-feet for rain-water floods and to 7100 second-feet for snow-water floods. This reduction in flood flows could be obtained by the use at times of a maximum reserve for flood control of 92,000 acre-feet, about two-fifths the total capacity of the reservoir. The effect of including this flood control feature upon reservoir stage and the yield of water and power from the Pardee reservoir is derived from a comparison of two sets of computations of the yield, one with and the other without flood control. As in studying the effect of the inclusion of a flood control feature upon the yield of the Keunett reser- voir, both sets of computations were carried through the entire period of measured flow^ on a daily basis instead of on the usual monthly basis in order to make the set without flood control exactly comparable to the one with flood control included. The latter had to be carried through on a daily basis to accoinniodate the requirements of the reservoir operating diagram which i-equires a daily atljustment of reservoir level during the flood season. The stream flow data used are those published in the Water Supply Papers of the United States Geological Survey for the Clements gaging station together with those in preparation for publication. No deduction was made for the 59 square miles of drain- age area between Clements and the dam. The assumptions employed in these computations are listed on page 298. The effect of including this flood control feature upon the reservoir stage is delineated upon Plate XXIV, "Effect of Controlling Mokel- • Water Supply Paper No. 551 of the United States Geological Survey, recently published, places the maximum discharge of the Mokelumne River at Clements at 25,500 second-feet. This is obtained by applying the rating curve of the 19H flood to the gage heights of 1907. The crest discharge of the 1907 flood has been published as 17,000 second-feet in former publications including Water Supply Paper No. 299 in which are printed the daily discharges of the 1907 flood. The figures contained in Water Supply Paper No. 299 have been used in preparing tiiis volume. Should the dally discharges of the 1907 flood be revised by application of the 1907 gage heights to the 1911 rating curve, the increase in their values would be so substantial as to require a complete revision of the analyses of floods on the Mokelumne River con- tained in this volume in ordor to make the analyses harmonize with the increased discharge values. PLATE XXIV. r ^ OCT. N(v 1910 3RIL MAY JUNE JL LY AUG. SEPT. ^^^ , [■ / '^-T- l-« ii!;^ Stage - Flood control -200 -200- -100 -20- •«- -10- ■D C 0) 0) ^/ ^J _ l>>:^ :; -Stage -Municipal draft with incidenta affected by coordination with f loo 1 1 r 1 1 1 1 power ^ ^ ^'~* ' "J acontrol ^^ J ■ 1 1 1 1 . 1 II '1 i • .... /° ^ ■" "■ lUg ....J -100- 1 4- <1> t /j^ /] e bw-uncorttrolled-*i Jv J A 4] =fi-n --Streaoi flow-controlled :[TT^rnj\- ^ U. L L L 1 L ^ c > ] ca \ \ , . , . ' — ' ■-■"— — - ■ 19 16 I OCT. NljPRIL MAY JUNE JULY AUG. SEPT. ^^-ro -0 — ^U — if- i A "««N _ 1 1 •" "^ N 2^d -200-(/) ^ Oh ssive rainfall index ■20-? 03 (/) D x: -10- c '/ / 'V ^ I ■*v "^ C ['^ t OJ u -•■■■■■ -100-^ d V -*^ Ik / l_ : Lf l/\ V\ ^ > W r 1^^^ b-.^ 1'* j OCT. N<| 1922 'RIL MAY JUNE JULY AUG SEPT. ^ (f) i_ nj ^ / I >»«, /-v — --. -s -200-0 222^ -200-1- -100- 1-0— Lq— -20-175 >^ CD "O C -10- OJ 1 1 ^ *^ ik ^J "^ ■^ 0) i ^ ^^ DO ra \ I/) , 1 nn- 1 / ^t 1 % ^ / % u./^ 1 i I^rr ^ J ' ^ irvoir stage line^ or i.G.D. Yield in power through reservoir tor with flood control s eeological Survey ))ith incidental power, ( rainfall m a normal F Controlling Mokelumne River Flc STAGE OF PARDEE RESERVOIR IF OPERATED PRIMARILY FOR MUNICIPAL SUPPLY MAXIMUM CONTROLLED FLOW AT CLEMENTS RAIN WATER FLOODS 5,300 SEC FT. SNOW WATER FLOODS 7,100 SEC. FT. j MAXIMUM FLOOD OF RECORD 20,600 SEC FT. 1 RESERVOIR CAPACITY 222,000 AC FT. MEIGHT OF DAM 345 FT. )ODS 1— I90A I905 , „ „.„ .„„„ I906 I907 22.2 200- -100- — 0- 322. 200- -200— ^ ' Y~ ^ \I ]siaet- Flood tonlrol I ^\A * ■*w:n ri \| 1/ 4 L Vn -'^ ' ^ ^ \ ' 1] rl \ '7 Mn -M-i-|--r-| r "~ ~~- T ^ ^ ■^ V M 1 J'O 1 yT\^ 1 ^ r: \ 1 V. < / ■< ^ — u V- y \ .X- ^ _ _ _ _ c^ p. r-A ^ f __ _ _ _ _ _ _ _ _ _ _ — ~- __ A "4 ■ Ji^ ,. ' ^ / ^ — -f 1 1 \ S ^ %s ^-d 7 ~" "— ^: si v; ''\ H ■■ \ ' '-. St3|e-Muniapal draft with inddantal powar _1_ - F* r=5 1 .. ■■ •■' frr' "Progressive rainfall inden 1 Stajo-Municipal draft «ilh Incidental po«er ^ r«; - \ 1 1 ....■ 1 rfected l» coordinc ition wim flood control ... •■• ^ 1— -Stream flow-uncontrolled 1 _ 'Reservoif sfaje on Od 28. 1904 MmputK) from a full resenwr on July 1, '9(M,ii$in< _ -_ — Progressive rainfall index 1 1 — — — — — — — n - - - - - - - 1 t h ^ k — It; 4fe \ h - — - - — -f - ^ — - — — — \- - — |\ - - -.-'^ \ -i- .- - — — _- _- _ _ — — ■ " earn fiow-controlied. 1 rl m^ __ I _ I I I I A 1 I A I ■^ ^ ■^ I 1 ir i f %c IS t -^\i\ /V I ^ i ^T I z z I I z. _L I z h 4 _ =1 h Vir *fc- jl "^^H^^^W ^m£u4-u_ 1 -^ P —0-1 ^ CT -L ■ ■- 1910 NOV. L. 3EC Lss U£= £^ 19 II 1— OCT l—J EC AN I"! r ,11 LI Vwi VRIL u . — utt 912 "I b4 EPT. ~ "~ i±J 10V — — — jfl IvdV^j^l ■ -■, y..|-| ..MM M 11 "r^^tsuu 1913 -u s HJr- d\i 1 1- 4"" ^ / \ _p_ . -.- / Nl t 7 f ■V, > §-'« Jj-200 JiiLj_ > ^ / ^ ~^ "■ N I Y' / T ^ ^ |-|^ 1 = ... / ■"■ ~%. ' --, ■■■ V. 1 — " \ p-< ' ^ -», , m O =i _ f^ P - .=^ - 1— 11 r ::- ;v — ■^ - - _ - -, ^ ■= ^ - -=i _ — — — - - — — — — — — — — -j — — — — — — — — ■^ ::= ^ ■^ — ~ v5 =- ^ — \ - ^ — — , _ -) /^ — _ _ _ J _ _ _ _ ::^ . o — OHOO- - ~ — =~ r ~J-^ Tf i 'Stream flo« ntrolled — -^ — - — — - — — — - — — =; ^ — — — — 7 ^ — — — — — — — — — — — — — — " — ^ — — - - ■^; — — f JL ~ — — — - - — - — — - I .Stream flow-wnlrolled ^ ^ / ■V, ■^ c ■a : ■ - V ' II , k % ■- c -■> 1 h I ( w \ \ \ . ■•.,• I-..-- .-•■ ... " D v> ifl A ^l, *JW' i ' V , W . /^ ,^ \ ^ ^rN (\ r-J r^ Jr! 3 Jlr ryffff^ ^ 1 "V 1 ^ -'^ V , l;'^ _r \ A .1 , h~- Mr" ";w 1 c„. 1,222 > 200- lO o — M o — ^100- OCT. 1! 16 ^OV. DEC JAN. rCB HAB. APRIL jaj— =^ 19 7 AUG. SEPT. CT NOV. )EC JAN. 1918 , UG. S EPT OCT. EC. JAN FEB. AR. I9IS JL^ AUG. SEP OCT. J -20 — l< E ' J= ■D c S-20- -10- \ 1 1 1 1 / / ^ y,?n' < / •~~ ( .■'■-. A T 7 ^ ! .b Stage- Rood conlfo 12.0- / / ' u 1^ / '-^ k. 1 ■ '■ . \ \ / ~- J i_j .V , XC^ V- / "^ r^ "■ fV 1 -— I — ' ly 4 / s^ ^ « "^ ^ i ^ /= =^ -5 M -— _ x~ — _ _ _ L :!! :=- ^ _ _ _ _ _ _ _ /- _ _ _ _ _ Z ■*■ =!r = ■=s ^ ^ ^ ^ _ _ - ^ - - - - — _ ' - A _^ ^ - 8^ — -^ -^ — ■■*, ^- ..^Prog alfrfall Mt - — — Sla e-Mun jpa draft. 1 1 r- tti incidenlat powers ^ ^ 1~. - f^ — - - — - — — '— "- - — - - - ~ ■^ - f-- — - - ~ — — — — — — — M - ^,00 - qr^ ■■.. .... -^ ^ -^ .., •■. •■ ■■ » .. >. 1 bo Stream flow-uncontrolled -^Ll | 1 1 1 ,1 a) h Slreatn flow-controlled - ■•■ 1 f^ -. — ^— — - ^ ^ n .^- 1 'fOo^- ^ A A - J^ t;; _ — _ _. _ _ — ::: Jl\ ^ _ 4^ ^J4=^U44k _ _ , ^ _ _ 1 — -^r^ — _ - r- ^ '\J J^ ^ "c" - - - - — - ^ - - L — oJ 222-1 222-, ^ ^, IS 2 2 . ?f."r' i 1 19 2. I iJ OCT Uu J_l 1 r 1 - 1-^1_ L. 1924 **■ =^ III Lk=! FEB MAR. APRIL li. UN U L t.. 925 AU s EP OCT. 200- -100- -200- •X i\ ~/ > V -fr'>4-TT X 1 1 Ll i Id-^ ■ - P tH ' ^ ~^ ' - ~ i 1 K f Tr-rT ~^^r^U MM ■ ^; ■ IV-' y. j' / ) TT-^ ' "-r H^ 1 - ■■.•■ "* .n ;■ -^ r^ 1 1 Fr^ ..^taSe-Mutiicipa ' -,'-^ "^"^ / ^ Stage -Honicipsi draft wilh incidental jjoiver" >»a kj ^ ■= sie /Stage- Municipal draft witti incidental power ~ ~" ■■ 1 V. 1^ U-rl III 1 y stage -Municipal draft witti incidental power t! r^ ^ i- ~- ~- __; ,/ ^ ■'j-, ■>■ ^ f ' dlr coordm ^ " ^ Pro|ressTve rainfall index- -■. ^ -"1 / (feded lycooninaho trol • J " 1 ■•■.■ ■■■, A 1 ' ■-•■ .. . ^ ■.. rH ' ' 1 ^ 1 ^ ~ ~ ' 1 . •. TT ~ _ h ^ ^ ~ ' — — *■ ^ ^ ~ ~ 1 r -^ • — 1 i ' v'"l ... - H #" =5 r'' _ Stream flow-uncontrolled — A f j 1 1 _ __ -- - - \ — U-- 4- J h/ _ _ _ _ _ _ _ , H _ _ _ "■■ h* :: ■:i_ "A :i 12. - :^ L? fe S itk _ _ _ _ 1 _ ^— xU^ j -L- - ^ - — L L L — - - - ~ ^^ ~ ~ ~ ]!/ fi J M H ■=4^ -7 — — ; [d ^ ? ^ = !!a - - — - - — \- - H - - A ~ -V — — - - - ~ - - -^ C =^ ~ ~ 1-^ JJXLCT^ ;^i>^ yN M Wr^^i^ ~~ ~ ir -120 PLATE XXIV. •22.2 200- (-200- [-20- ,r. ^ rpT CT «0V P EC J«n. FEB. >IA APR ^ ,, J UN 9I« ILY UC EP- CT 0« DEC AN EB „„ , PBIL 9 1 E ILV UG OCT tow AN EB , Pn, 9 \i _, UM ULV AU ;. 5 EPT. < " "^ .^ 1 V ' t / -~- r N n rrr-np Ij // ~i [ — 1 p— 1 — 1 r' ^-. \ ^ r—- '~- ■v 222 ( ^ / / V, Sla«e- Flood c.nlrol "^ p / ^ ■~~J n / '=^0] "^ 200i "S- .«, \ \ / > -^ .^ ^ r' ^ / r ^ O- ^ v^ 1 / Y ^, - — -t- - = -, -- — -If ^^ \^ -A^ ^ / ^ - Slsge- Municipal draft with i 1 1 ncidcnla power- ^ 5>- - ^ --- - - t rf -* ^ ^ p Stage-Municipal draft wifti incidental power affecled by coofdinalion will) flooocofilrti! _ — - — — -^ ^ < --- X^ ^ - _ - J - — ^- - — ~r^ -^ - — — — — - -— — *~ - M- ^ •-r "■ ~ — — ^ ^ — ^ — — -1 "- ~": •• — — " ^ — "~ — ' — —. 7- T.. -^ 7: ' . — ^ — — — -;^ r ^ — ^ ^^ r-- ■" — - — — - ' "1 — - 1 . <.;"■ J 1 '-- ' / : 100-4 v^ - 1~ k - - "•■, Progressive rainfall index' . In _J^ .^1 A & Ir C ri T" M m\ it ^ A^ -- - ^ - - - m- j_ il ^W U Jj U^j y /! "« £ - a - - - -T^Ffn^^,l.Ui^^' ^ ' 'VsK Stream flow-aintrolled ^"^>^l Mil _ - _ -_ ^A L H^^M %^ m h s ^ - j^ J^ - J_ 2223 r222 1-222 m ,0. SEPT. OCT NOV C EC JAN FEB MAD APHIL MAY 19 20 JUNE JULY UG. SEPT. OCT NOV EC. JAN. rEB MAP APRIL MAV n'® ^'y UG SEPT. ■ „^, „ov DEC 1922 JUNE JULY AUG SEPT ...S! ^ h- :i + ^ " "" l__l. f = -i- X - - -.y^ 1 1 1 m -^T^ -^^ 1 — 1 — \ — r*"**^. _ \ M IJ 111 M IJ^yiT "PrT "^^^ -200-0 4^^-, 1 :z zzzt f-^: $#T := ^=t±t «l»^__ V ■^ ti^id z: ^ ^^ -.. " 5-' t 1 -r^ pStage- lunicipal draft with mtiden (ITeded b;* coonJinali9n with f **^ ^- — ^^ ro "^^^ T Stag Municpa dra " Md unlrol ^^ ^^™ ^ — ,-^ i __^ .'' ~\ ~~^ 1 f--~j^ ■ ,••... -.■■•■—■ '""^ 100 1 ^ ■■.... " "■'■ " ■ 1 ;■■ ' '■ / « 1^ :" '- -ir- 7\ i ^ k Jfel . ■••v . ■ AJi 1 -+_=. .r^ 1 i -^-Mm Stz-; ..:r: £.~> ..^iij,^j.twf4w ^\^ &J- L L ^c — jJ-^--Zl^' f^^i _ =J— Lj-o— 22.2 L -20- 1;, Stsje of reservoir operareO for flood control alone S1»«e of rrstrwir 0D«r3Tei) for mun-coal Suppljr w (»»era«e)*nn|tnefsrof wpacjfjf of 15,000 K.W. 1 B[ Dugn reservoir for pnor ngnrs. 'V^Va-^ Hean dally flow (unwn trolled] o X>^-A.-^ Mtan dailj flow([Onlnjlltd) of H lere affected bj coofOmation mih flood contn from records of United States Oeclogital Sui r operated for municipal supplj with incjdeniai pon Effect of Controlling Mokelumne River Floods STAGE OF PARDEE RESERVOIR IF OPERATED PRIMARILY FOR MUNICIPAL SUPPLY MAXIMUM CONTROLLED FLOW AT CLEMENTS BAIN WATER FLOOOS 5.300 SEC FT SNOW WATER FLOODS 7, 1 00 SEC FT. MAXIMUM FLOOD OF RECORD 20.600 SEC FT. RESERVOIR CAPACITY 222.000 AC FT, HEIGHT OF 0AM 345 FT. THE CONTROL OF FLOODS BY RESERVOIRS. 121 umiie River Floods lipori Staoo of Pardee Reservoir." It is assumed in preparing this plate that the Pardee reservoir was constructed some time prior to 1904, the opening year of continuous stream flow measure- ments on the Mokelumne River, and operated both with and without flood control through the succeeding years for a municipal supply of 200 million gallons per day together with incidental power development as proposed by the East Bay Municipal Utility District. The reservoir stage for every day of the 21 years from 1905 to 1926 is indicated by lines extending across the plate in several rows. Their vertical posi- tion, read on the reservoir stage scale, shows the number of acre-feet of water in storage at all times. On this scale, the space between parallel guide lines represents 20,000 acre-feet of reservoir capacity. The top guide line of each row represents a full reservoir and the bottom one an empty reservoir. The heavy black line extending across each row indicates the stagd were 200 million gallons per day drawn from the reservoir and 140,000 acre-feet per year passed by the dam for prior rights. The heavy red line indicates the departures from this stage by reason of the introduc- tion of the flood control feature. The light red line indicates the stage w^ere the reservoir operated for flood control alone in accordance with the diagram. Red figures translate into feet of depth the greatest draw down from a full reservoir required by flood control during each season. A light black line in each row below the reservoir stage lines indicates on a special scale superimposed on the reservoir stage scale, the undisturbed daily flow in the IMokelumne River at Clements, The light red line close at hand shows the flow below the dam as controlled by the coordinate operation of the reservoir for flood control and con- servation. A black dotted line shows throughout the flood season the daily value of the progressive rainfall index used in entering the reservoir operating diagram to obtain the flood control reserve on each day. In 8 out of the 21 seasons displayed on the plate, flood control requires a maximum dei>th of empty space from 50 to 52.5 feet below the full reservoir level. In the other 13 seasons, the maximum depths required range from to 50 feet. In one-third of the seasons, the water level due to conservation operations is lower than required for flood control. The average actual depression of water level due to flood control is 10 feet, 3.4 per cent of the average depth of water in the reservoir at the dam. The reservoir level is depressed for flood control more than one foot, about one-quarter of the entire elapsed time of the analysis. The water yield of the reservoir is practically* the same both with and without the inclusion of the flood control feature. A continuous draft of 200 million gallons per day can be sustained through the entire 21 years either with or without flood control except in the fall of 1924 when there is a .shortage of 19.9 billion gallons with and 19.1 billion gallons without flf)0(l couti-ol, a diffci-once* of 1.1 per cent of the annual supply. • It appears probable that the yield of water and power both with and without flood control would be the same were indices of snow-on-the-^ound used instead of rainfall indices in constructing and applying that part of the reservoir operating diagram pertaining to snow-water floods (sec page 213). 122 WATER RESOURCES OP CALIFORNIA. The average incidental power generated is 6640 kilowatts without flood control and 6510 kilowatts with flood control, a difference of 2 per cent. In both instances the entire amount is secondary power. If flood control were attained by holding the maximum reserve empty throughout the flood season the inclusion of flood control would affect the yield of water and poAver a little more than if attained by use of the reservoir operating diagram. In the computations for this com- parison, 92,000 acre-feet of capacity are held empty each year until April 21st, the close of the rain-water flood season. The reserve is then reduced to 13,000 acre-feet. This is held empty from May 11th to July 5th, the season of snow-water floods. Under this plan of opera- tion, flood control increases the shortage in water yield in 1924, the only year of deficient supply, from 19.1 to 24.6 billion gallons, an increase of 2.8 per cent of the annual supply. A full supply is obtained in all of the other 20 years analyzed. The average power output is reduced 2.9 per cent. The following tables present yearly summaries of all the computa- tions of yield of the reservoir. Tables of monthly summaries, because of their volume, are placed in a separate chapter. THE CONTROL OF FLOODS BY RESERVOIRS. 123 PARDEE RESERVOIR ON MOKELUMNE RIVER Table of Yearly Summaries of Water and Power Yield Computed on a Daily Basis Showing the effect of inclusion of the flood control feature. (See Chapter VIII for corresponding monthly summaries.) Table 6 — With and without flood control by reservoir operating diagram. Table 7 — Yield compared for two methods of flood control. Table 8 — Summary of Tables 6 and 7. 124 WATER RESOURCES OF CALIFORNIA. TABLE 6. PARDEE RESERVOIR WATER AND BOTH WITH AND WITHOUT FLOOD CONTROL Height of dam 345 feet. Capacity of reservoir 222,000 acre-feet. Yearly Summary of Computations For corresponding monthly sum Run-off Without flood control Power Year at Gements in acre-feet Stage of reservoir at beginning of year in acre-feet Municipal draft in acre-feet draft through turbines including water passed for prior rights in acre-feet Evapora- tion in acre-feet Waste over spillway in acre-feet Deficiency in municipal supply in acre-feet Average power head through period of operation in feet Average power yield in lalowatts (Load factor= 1.00) 1905 578,060 145,860 224.040 241,480 5,860 135,880 303 6.320 1906 1,415,400 116,660 224,040 325,760 6,400 794,280 307 8.650 1907 1.642,700 181,580 224,040 398,680 6,150 1.046,510 313 10.820 1908 455.340 148,900 224,650 236.970 5,820 10,770 299 6.020 1909 1.278,230 126,030 224,040 346,350 6,160 618,790 315 9,480 1910 788,060 208,920 224,040 279,830 5,740 355.440 314 7.670 1911 1,51.5.830 131,9.30 224,040 315.670 6,210 970,250 311 8,630 1912 410,540 131,590 224,650 169,020 .5,340 10,360 279 3,870 1913 405,950 132,760 224.040 183,270 5,820 3,280 286 4,370 1914 1,075.890 122,300 224,040 302.610 6,240 541,320 314 8,280 1915 829 400 123,980 224,040 248,280 6,210 336,460 303 6.580 1916 1,049,320 138,390 224,650 303,750 6,210 508,860 308 8,240 1917 828,860 144,240 224,040 275,060 6,260 352,930 302 7.190 1918 546,170 114,810 224,040 179,270 6,220 116,680 293 4.680 1919 573,130 134,770 224,040 196,310 5,720 171,570 294 4,970 1920 506,310 110,260 224,650 159,980 5.870 64,340 283 3,930 1921 823,280 161.730 224,040 282,720 5,890 345,540 313 7,660 1922 974,010 126,820 224,040 243,190 6,300 450,540 301 6,390 1923 648,880 176,760 224,040 313,070 5,860 152,490 300 7.930 1924 206,650 130,180 166,010 140,000 1,760 58,W0 208 2,590 1925 802,990 29,060 224,040 190,680 6.610 277,080 288 5,100 Total 17,355,000 4,649,250 5,331,950 122.650 7,263.370 58,640 Average 826,430 221,390 253,900 5,840 345,870 2,790 296 6,640 THE CONTROL OF FLOODS BY RESERVOIR.S. 125 ON MOKELUMNE RIVER. POWER YIELD BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary see Table 6a, page 300.) Yield in municipal supply 200 million gallons daily. Installed capacity of power plant 15,000 k.w. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements— rain-water floods, 5,300 sec.-f t; snow-water floods, 7,100 sec.-f t. Maximum reservoir space required — rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Stage of reservoir at beginning of year in acre-feet Municioal draft in acre-feet Power draft through turbines including water passed for prior rights in acre-feet Evapora- tion in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in municipal supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor^ 1.00) Year 145,860 114,640 165,670 148,900 126,030 160,810 121,390 131,590 132,760 122,300 123,980 138,390 144,240 114,810 134,770 110,260 161,730 124,600 176,760 127,850 29,060 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 163,680 224,040 241,160 330,460 415,450 236,970 345,820 269,630 339,400 169,020 183,270 328,090 230,140 339,580 259,550 179,270 196,310 159,980 280,900 235,780 288,000 140,000 189,850 5,860 6,400 6,150 5,820 6,160 5,740 6,210 5,340 5,820 6,240 6,210 6,210 6,260 6,220 5,720 5,870 5,890 6,300 5,860 1.760 6,610 111,840 571,150 521,260 552,980 224,410 730,430 449,110 333,570 346,920 263,350 293,730 394,730 169,370 182,850 26,380 232,320 492,570 10,770 114,450 103,660 205,550 10,360 3,280 66,730 21,030 126,110 105,090 116,680 171,570 64,340 55,850 61,000 10,520 99,770 60,970 302 305 305 299 304 298 302 279 286 302 302 298 302 293 294 283 302 300 297 206 286 6,300 8,680 10,820 6,020 9,010 6,900 8,850 3,870 4,370 8,450 6,080 8,690 6,790 4,680 4,970 3,930 7,170 6,220 7,250 2,570 5,040 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 4,646,920 221,280 5,358,630 255,170 122,650 5,840 5,145,700 245,030 2,098,030 99,910 60,970 2,900 292 6.510 Total Average 126 WATER RESOURCES OF CALIFORNIA. TABLE 7. PARDEE RESER CX>MPARISON OF WATER FOR TWO METHODS OF Yearly Summary of Computations (For corresponding monthly sum Height of dam 345 feet. Capacity of reservoir 222,000 acre-feet. Run-off at Clements in acre-feet Fleod control by reservoir operating diagram Maximum controlled flow at Clements— rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Maximum reservoir space required — rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Year Stage of reservoir at beginning of year in acre-feet Municipal draft in acre-feet Power draft through turbines including water passed for prior rights in acre-feet Evapora- tion in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in municipal supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor= 1.00) 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 578,060 1,415,400 1,642,700 455,340 1,278,230 788.060 1.515,830 410,540 405,950 1,075,890 829,400 1,049,320 828.860 546,170 573,130 506,310 823,280 974,010 648,880 206.650 802,990 145,860 114,640 165,670 148,900 126,030 160,810 121,390 131.590 132.760 122.300 123.980 138.390 144.240 114.810 134.770 110,260 161,730 124,600 176,760 127.850 29,060 224,040 224,040 224,040 224,650 224,040 224.040 224.040 224,650 224,040 224,040 224,040 224,650 224 040 224,040 224,040 224,650 224,040 224,040 224,040 163,680 224,040 241.160 330.460 415.450 236,970 345,820 269,630 339,400 169,020 183,270 328,090 230,140 339,580 259,550 179,270 196,310 159,980 280,900 235,780 288.000 140.000 189.850 5,860 6,400 6,150 5,820 6.160 5.740 6.210 5.340 5.820 6.240 6.210 6.210 6,260 6.220 5.720 5,870 5.890 6.300 5.860 1,760 6,610 111.840 571,150 521,260 552,980 224,410 730,430 449.110 333.570 346.920 263,350 293,730 394,730 169,370 182,850 26,380 232,320 492,570 10,770 114,450 103,660 205.550 10,360 3,280 66,730 21,030 126,110 105,090 116.680 171.570 64.340 55.850 61.000 10,520 99,770 60,970 302 305 305 299 304 298 302 279 286 302 302 298 302 293 294 283 302 300 297 208 286 6,300 8,680 10,820 6.020 9.010 6,900 8,850 3,870 4,370 8.450 6,080 8,690 6,790 4,680 4.970 3,930 7,170 6.220 7,250 2.570 5.040 Total Average 17.355.000 826.430 4,646,920 221,280 5,358.630 255,170 122.650 5,840 5,145,700 245,030 2,098,030 90 910 60,970 2,900 292 6.510 THE CONTROL OF FLOODS BY RESERVOIRS. 127 VOIR ON MOKELUMNE RIVER. AND POWER YIELD FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 7a, page 312.) Yield in municipal supply 200 million gallons daily. Installed capacity of power plant 15,000 k.w. Flood control, holding maximum reservoir space required (rain-water floods, 92,000 ac.-ft. snow-water floods, 13,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Clements— rain-water floods, 5,300 sec.-f t. ; snow-water floods, 7,100 sec.-f t. Stage of reservoir at beginning of year in acre-feet Municipal draft in acre-feet Power draft through turbines including water passed for prior rights in acre-feet Evapora- tion in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in_ municipal supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor= 1.00) Year 101,560 103,660 130,000 123,510 113,040 124,900 118,910 115,200 109.050 109,280 118,860 127,440 129,190 108,520 121,490 97,250 130,000 113,830 130,000 113,190 29,060 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 149,020 224,040 234,520 352,970 412,760 217,880 386,170 290,070 347,480 169,220 175,860 331,090 253,800 340,750 262,890 189,640 193,870 177,420 301,710 256,700 299,750 140,000 214,330 5,860 6,400 6,150 5,820 6,160 5,740 6,210 5,340 5,820 6,240 6,210 6,210 6,260 6,220 5,720 5,870 5,890 6,300 5,860 1,760 6,610 111,540 657,380 864,760 17,460 617,970 255,830 877,030 17,480 504,940 336,770 434,230 350,310 113,300 134,780 65,620 307,810 444,980 136,040 248,080 148,270 141,480 32.030 18,370 64,780 41,730 6,030 38,960 25,820 18.280 75,630 285 295 298 285 292 290 295 267 273 294 293 292 293 284 286 274 292 291 282 198 279 5,700 8,850 10,560 5,220 9,490 7,090 8,750 3,700 3,950 8,200 6,340 8,450 6,580 4,730 4,760 4,230 7,440 6,420 7,010 2,450 5,420 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 4,632,260 220,580 5,548,880 264,230 122,650 5,840 6,496,310 309.350 535,750 25,510 75,630 3 600 283 6,450 Total Average 128 WATER RESOURCES OF CALIFORNIA. TABLE 8. PARDEE RESERVOIR ON MOKELUMNE RIVER. SUMMARY OF WATER AND POWER YIELD BY YEARS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 6 and 7. (For corresponding monthly summary, see Table 8a, page 324.) Height of dam 345 feet. Yield in municipal supply 200 million gallons daily. Capacity of reservoir 222,000 ac.-ft. Installed capacity of power plant 15,000 k.w. Year Without flood contro Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements — rain-water floods. 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Maximum reservoir space required — rain-water floods 92,000 ac.-ft.; snow-water floods. 13,000 ac.-ft. Flood control, holding maximum reservoir space required (rain-water floods. 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft.) In reserve throughout flood season Maximum controlled flow at Clements — rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Municipal draft in acre-feet Deficiency in municipal supply in acre-feet Average power jield in lalowatts (Load factor= ].00) Municipal draft in acre-feet Deficiency in municipal supply in acre-feet Average power yield in Icilowatts (Load factor= 1.00) Municipal draft in acre-feet Deficiency in municipal supply in acre-feet Average power yield in kilowatts (Load factor= 1.00) 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 224,040 224,040 224,040 224,650 22-1,040 224,040 224,040 224.650 224,040 224,040 224,040 224.650 224,040 224,040 224.040 224,650 224,040 224,040 224,040 166,010 224,040 58,640 6,320 8,650 10,820 6,020 9,480 7,670 8,630 3,870 4,370 8,280 6.580 8,240 7,190 4,680 4,970 3,930 7,660 6,390 7,930 2.590 5,100 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,040 224,040 163,680 224,040 60,970 6,300 8,680 10,820 6,020 9,010 6,900 8,850 3.870 4,370 8,450 6,080 8,690 6,790 • 4.680 4,970 3,930 7,170 6,220 7,250 2,570 5,040 224,040 224,040 224,040 224,650 224,040 224,040 224,040 224,650 224,040 224,010 224,040 224,650 224,040 224,040 224,040 224,650 224.040 244,040 224,040 149.020 224,040 75,630 6.700 8.850 10,660 6,220 9,490 7,090 8,760 3.700 3,950 8,200 6,340 8,450 6,580 4,730 4.760 4,230 7,440 6.420 7.010 2,450 5.420 Total Average 4,649,250 221.390 58,640 2,790 6,640 4,646,920 221,280 60,970 2,900 6.510 4.632,260 220,580 75,630 3,600 6.450 Temperance Flat Reservoir on San Joaquin River. Among the reservoirs of the "Coordinated Plan,"* for developing the State's waters is one on the San Joaquin River, six miles upstream from Friant. It is proposed that a dam 595 feet high be constructed at this point. This would create a reservoir of 1,071, OOO acre-feet capac- ity, sufficiently large lo ('(ju.ilize seven-eighths of the mean annual run-off of the San Joa(|uin Kivei* for irrigation use and generate on an average 62,000 kilowall.s of incidental power at a plant erected near the base of the dam. The installed capacity of the plant would be 220,000 k.v.a. Also, large floods would be controlled to about one- • See Bui. No. 12, "Summary Report on the Water Resources of California and a Coordinated Plan for their Development," Division of Engineering and Irrigation, State Department of Public Works. THE CONTROL OF FLOODS BY RESERVOIRS. 129 quarter of their natural size. A full description of this unit of the "Coordinated Plan," together with estimate.s of the water and power yield without flood control is contained in Bulletin No. 16, ' ' The Coor- dinated Plan of Water Development in the San Joaquin Valley." The effect of including the flood control feature of the plan is described in the following pages. The rule for operating the Temperance Flat Keservoir for flood con- trol has been developed in the previous chapters of this volume. It is expressed on Plate XX, ' ' Reservoir Operating Diagram for Controlling Floods on the San Joaquin River" (p. 84). It would limit rain-water floods, including the maximum of record, to 10,700 second-feet and snow-water floods to 14,200 second-feet. The maximum rain-water flood of record had a mean daily flow of 38,800 second-feet. It occurred on Jan. 31, 1911. The maximum snow-water flood discharged 23,100 second-feet and occurred on June 13, 1911. The reduction in flood flows obtained through the use of this reservoir operating diagram requires a reservation at times of a maximum space of 177,000 acre- feet, one-sixth of the total capacity of the reservoir. The effect of including this flood control feature upon the reservoir stage and upon the yield of water and power is derived from a com- parison of the yield computed both with and without flood control. In order that this might be an exact comparison, both sets of computations are carried out on a daily basis to conform to the requirements of the reservoir operating diagram which calls for daily adjustment of reser- voir level during the flood seaso2i. The parallel sets of computations are made in exactly the same way except for the exclusion of the flood control feature in one set. They are carried out similarly to the com- putations of yield described in Bulletin No. 16, except that they are made on a daily instead of the u.sual monthly basis, include only the 18 years of continuous stream flow record and make no deduction for the 108 square miles of drainage area between the Friant gaging station and the dam site.* The stream flow data used are those published in the Water Supply Papers of the United States Geological Survej" for the Friant gaging station together with those in preparation for publi- cation. The assumptions of the computations are listed on page 331. The effect of inclusion of the flood control feature upon reservoir stage is delineated on Plate XXV, "Effect of -Controlling San Joaquin River Floods upon Stage of Temperance Flat Reservoir." Here the reservoir stage is shov/n day b}' day from 1908 to 1926, the period of continuous measurement of flow in the San Joaquin River. It is assumed for constructing this plate that the reservoir was in existence in 1907 and operated through the succeeding years as proposed in the "Coordinated Plan," flr.st excluding and then including the flood con- trol feature. The volume of water in storage throughout the 18-year period is shown on each day by the vertical position on the reservoir stage scale of lines extending across the plate in several rows. To the scale of the plate, each space between horizontal guide lines e(iuals 100,000 acre-feet. The top guide line of each row represents a full re.servoir and the bottom line an empty reservoir. * The water and power yield published in Bui. No. IG is an estimate made on a monthly basis covering the 54-year period 1871-1925. It makes a deduction of 1.5 per cent from the measured flow at Friant for the area between the gaging station and the dam site. For this reason the estimates in Bui. No. 16 are not exactly comparable with the ones contained in this volume. 130 WATER RESOURCES OF CALIFORNIA. The reservoir stage operating with the flood control feature excluded is indicated by the heavy black line extending across each row. The departure from this stage caused by the inclusion of the flood control feature is shown by a heavy red line. A light red line indicates the reservoir stage were it operated for flood control alone in accord with the diagram. Red figures translate into feet depth from full reservoir level, the greatest draw down required by flood control in each season. Below the reservoir stage lines in each row is shown in a light black line to a special scale superimposed on the reservoir stage scale, the uncontrolled flow of the river at Friant and in a light red line the con- trolled flow downstream from the dam when the "Coordinated Plan" with its flood control feature is in operation. A line of black dots shows the daily values of the progressive rainfall index used in entering the reservoir operating diagram to obtain the necessary flood control reserve. It is observed in reviewing Plate XXV that in 12 of the 18 seasons analyzed, the reservoir stage resulting from operation for conservation is less than that required for flood control. In these seasons the inclusion of the flood control feature does not affect the reservoir stage at all. In the other six seasons at times, the drawdown from a full reservoir level reaches a maximum of 35 feet, 6 per cent of the depth of a full reservoir at the dam. The average actual depression of the water level due to flood control is 17 feet, 3.5 per cent of the average depth of water in the reservoir at the dam. The reservoir level is depressed by reason of the inclusion of the flood control feature, one- quarter of the entire elapsed time of the analyses. The effect of the inclusion of the flood control feature in the ' ' Coor- dinated Plan" upon the water and power yield of the Temperance Plat reservoir is shown by the accompanying summary tabulations of the computations of yield with and without flood control carried out on a dail.y basis in order to accommodate the requirements of the reservoir operating diagram. Monthly and yearly summaries are prepared of these computations. The yearly summaries follow herewith but the monthly summaries, because of their volume, are placed in a separate chapter. These data show that the inclusion of tlie flood control feature has no effect at all upon the water yield of the reservoir and very little effect* upon the power generated. With flood control the average power output is 61,400 kilowatts and without flood control 62,000 kilowatts, a difference of 1.0 per cent. All is secondary power in both instances. If flood control were attained by holding the maximum reserve empty throughout the flood season instead of by use of the reservoir operating diagram, the inclusion of flood control would have a small effect on the water as well as on the power yield. In the computations for this comparison, 133,000 acre-feet of capacity are held empty each year until April 7th, the close of the rain-water flood season. The reserve is then increased to 177,000 acre-feet which is held empty from April 27th to July 16th, the season of snow-water floods. For these condilions, the average yield of irrigation water is reduced 1.0 per cent, the reductions occurring in the seasons of short supply, and the average power output is reduced 6.0 per cent. • It appears probable that the power yield would be almost identical .both with and without flood control were indices of snow-on-the-ground used instead of rainfall indices in constructing and applying that part of the reservoir operating diagram nertainincr tn onritir-H'O f c fl^rxlo C ooo r^ 01•}^ — - — — - PLATE XXV. -25 Effect of Controlling San Joaquin River Floods UPON STAGE OF TEMPERANCE FLAT RESERVOIR IF OPERATED PRIMARILY FOR IRRIGATION MAXIMUM CONTROLLED FLOW AT FRIANT RAIN WATER FLOODS 10.700 SEC. FT SNOW WATER FLOODS 14,200 SEC. FT. MAXIMUM FLOOD OF RECORD 38,800 SEC. FT. RESERVOIR CAPACITY 1,071,000 AC. FT. HEIGHT OF DAM 595 FT. ' C> 52411 -P, '1 g— . f- f=T-rp^S;2f- -^ -- -^ -p -^ T^ ff ^|f&^ ^ i"S^«,-^'SS^ ^"""1 ■ 1 ! '^~- ^^ — !_ uJ_ _J_ _LL ^^ ^^ _l^ _ _.'_ - i- ^ 5.,t..i,,j(.uj, T^%g^jif^1sli^^ ^^tF:;l:± t_. l5..t.-ir.i.i; "? e i= f-m S - - 5.| = °r tiLis.^*iJr ^ji;rT-itfUlr±--^ -l+r /* — ^ T-^ > ZZZu ^ ^ ? l;r:JrWfc 19 2 1 -! ; — "-V ''"'V- FF 1 IftcSwivv- 1 B ^ pi's — 1 a.L B^iPMall i i I'fJPf itfi =^;====:=::i:::=;=:=:==:==^^iHii==n^:i=^^^ -pM^Pi^ = = = ==^^^-^^^ r . t i Tt-Ii-1 "J-T 7i~ -^ s "T PtpM'ii^riP^iili^lfTO^M^^ 44= ^ ^ ^ £3 = - |^-trrrt4^?T| »;•■," •'^ ""ri- ij; _^ ^ J : lillil |. ' l ^ __: '"^ "--M-p— - 'vil^<.. .^-i U ' t r~-^ ,„ ;'"r° ,„.,„_„ EfFEcr OF Controlling San JOAQUIN River Floods ^V; "'SJKSST STAGE or TEMPERANCE FUT RESERVOIR , IF OPERATtO PBIMARILT fOR IRRIGATION _ ;:;_^ :__ . J-J3---i_^ J/T r "i \ ^ i I "i" --y- """ zrjziii^ 1 "" r tzA^ ' - j^ K" i"n-f---r ;■'' i t" +: --;--M^sc--l-^--' — r-h^i-i 1 -^ -1 r i — h ^ W^^ -imf ''^'i^^^^-l-^ =i=i-::;;j;^;:-i-- L : ^ ' ' " - ' -■> ^7'^ L^ L I.A.4 -|j L,'^4^'TT-t 1 1 l-i-i T-r4-' M ■ 1 1 ri It 1 n^-^f-J^riij. 1 1 M 1 M M 1 FlTiri i-J ^cn.r~^>. — >^^-H^-j-i 1 rrH-, ,Jj^ J THE CONTROL OF FLOODS BY RESERVOIRS. 133 TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. Table of Yearly Summaries of Water and Power Yield Computed on a Daily Basis. Showing the effect of inclusion of the flood control feature of the "Coordinated Plan." (See Chapter VIII for corresponding monthly summaries.) Table 9 — With and without flood control by reservoir operating diagram. Table 10 — Yield compared for two methods of flood control. Table 11 — Summary of Tables 9 and 10. ^..t»t iiiu power yield would be almost identical .both with ana without flood control were indices of snow-on-the-ground used instead of rainfall indices In constructing and applying that part of the reservoir operating diagram 1 THE CONTROL OF FLOODS BY RESERVOIRS. 133 TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. Table of Yearly Summaries of Water and Power Yield Computed on a Daily Basis. Showing the effect of inclusion of the flood control feature of the "Coordinated Plan." (See Chapter VIII for corresponding monthly summaries.) Table 9 — With and without flood control by reservoir operating diagram. Table 10 — Yield compared for two methods of flood control. Table 11 — Summary of Tables 9 and 10. 134 WATER RESOURCES OF CALIFORNIA. TABLE 9. TEMPERANCE FLAT RESER WATER AND BOTH WITH AND WITHOUT FLOOD CONTROL Yearly Summary of Computations (For corresponding monthly sum Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-o£f Without flood control at Irrigation Average Year Friant Stage of draft in Deficiency power Average in reservoir acre-feet Power Waste head power acre-feet at (no Evapora- draft over in irrigation supply through yield in beginning deduction tion in through spillway period kilowatts of for down- acre-feet turbines in of (Load year in stream in acre-feet acre-feet in acre-feet operation factor= acre-feet prior in 1.00) rights) feet 1908 1,115,000 797.100 1,800,000 13,700 1,699,100 488 73,800 1909 3,136,700 98,400 1,800,000 18,400 1,811,400 568,600 510 85,800 1910 .1,825,500 836.700 1,800,000 18,500 1,876,600 347,300 538 91.100 1911 3,562,200 419,800 1,800,000 20,100 1,831,700 1,416,500 556 91,900 1912 1,023,700 713,700 1,686,900 10,200 1,510,300 113,100 454 60,900 1913 874,100 40,300 863,300 100 936,700 1914 2,905,300 51,000 1,800,000 18,900 1,811,600 361,100 514 86,600 1915 1.954,600 764,700 1,800,000 19.200 1,808,300 250,400 540 88,700 1916 2,827,000 641,400 1,800,000 20,200 1,868,800 849,600 557 93,500 1917 1,860,100 729,800 1,800,000 18,900 1,804,700 176,900 537 88,100 1918 1,596,500 589,400 1,800,000 14,600 1,800,000 466 77,700 1919 1,191,400 371.300 1,505,700 8,300 1,302,600 294,300 416 49.200 1920 1,362,000 48.700 1,320.700 2,400 420,900 479,300 329 12.300 1921 1,580,300 87.600 1,576,000 5,600 1,361,500 224,000 344 42.700 1922 2,376,800 86,300 1,800,000 15,000 1,652,700 443 69.300 1923 1,604.900 648,100 1,800,000 16,400 1,800,000 500 82,900 1924 466,100 436,000 844,300 1,900 536,400 955,700 394 17,800 1925 1.413.400 56,500 1,387,600 2,600 111,400 412,400 298 2,900 T.tal 32.675.600 28,984,500 225,000 25,008,000 3,970,400 3,415,500 Average 1,815,300 1,610,300 12,500 1,389,300 220,600 189,700 490 62,000 THE CONTROL OF FLOODS BY RESERVOIRS. 135 VOIR ON SAN JOAQUIN RIVER POWER YIELD BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9a, page 332.) Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P.P. 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Friant — rain-water flood.s, 10,700 sec.-ft: snow-water floods, 14,200 sec.-ft. Maximum space required for flood control — rain-water floods, 133,000 ac.-ft: snow-water floods, 177.000 ac-ft. Stage of reservoir at beginning of year in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) Evapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Wa,ste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor= 1.00) Year 797.100 98.400 791.100 261.100 713.700 40.300 51.000 758.400 587.100 679.800 589.400 371.300 48.700 87.600 86.300 648,100 436,600 56,500 1,800,000 1,800 000 1,800,000 1.800.000 1.686.900 863.300 1.800.000 1.800.000 1,800.000 1,800,000 1,800,000 1.505.700 1.320,700 1.576.000 1.800.000 1.800,000 844.300 1,387,600 13,700 17,800 16,500 19.500 10.200 100 18.600 18.600 19.400 18,600 14,600 8,300 2,400 5.600 15.000 16,400 1,900 2,600 1,699,100 1,820,300 1,868,200 1,842,400 1,510,300 1,821,400 1,819,600 1,838,500 1,805,100 1.800.000 1.302.600 420,900 1.361.500 1.652.700 1.800,000 536,400 111,400 605,900 401,300 1,176,100 357,900 287,700 644.200 57,600 66,500 74,600 232,200 69,200 113,100 936,700 294,300 479,300 224,000 955,700 412,400 488 503 506 542 454 510 530 544 532 466 416 329 344 443 500 394 298 73,800 85,100 86,200 91,000 60,900 86,400 87,800 90,300 87,500 77,700 49,200 12.300 42,700 69,300 82,900 17,800 2,900 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 28,984,500 1,610,300 219,800 12,200 25,010.400 1,389,500 3,530,700 196,100 442,500 24,600 3,415,500 189,700 484 61,400 Total Average 9—52411 13(5 WATER RESOURCES OP CALIFORNIA. TABLE 10. TEMPERANCE FLAT RESER COMPARISON OF WATER FOR TWO METHODS OF Yearly Summary of Computations (For corresponding monthly sum Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-off at Friaiit in acre-feet Flood control by reservoir operating diagram Maximum controllci flow at Friant— rain-water floods. 10,700 sec.-ft.; snow-water floods, 14,200 sec.-ft. Maximum reservoir space required — rain-water floods, 133.000 ac.-ft.; snow-water floods, 177,000 ac.-ft. Year Stage of reservoir at beginning of year in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) 1,800,000 1,800,000 1,800,000 1,800,000 1,686,900 863,300 1,800,000 1,800,000 1,800,000 1,800,000 1,800,000 1,505,700 1,320,700 1,576.000 1,800,000 1,800,000 844,300 1,387 600 Evapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor= 1.00) 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1,115,000 3,136,700 1,825,500 3,562,200 1,023,700 874,100 2,905,300 1,954,600 2,827,000 1,860,100 1,596,500 1,191.400 1,362,000 1,580,300 2,376,800 1,604,900 406,100 1,413,400 797,100 98,400 791,100 264,100 713,700 40,300 51,000 758,400 587,100 679,800 589,400 371,300 48,700 87,600 86,300 048,100 436.600 56,500 13,700 17.800 16,500 19,500 10,200 100 18,600 18,600 19,400 18,600 14,600 8.300 2.400 5,600 15,000 16,400 1,900 2.600 1,699,100 1.820,300 1,868,200 1,842,400 1.510,300 1,821,400 1,819,600 1,838.500 1,805,100 1,800,000 1.302,600 420.900 1,361,500 1,652,700 1,800.000 536,400 111,400 605,900 401,300 1,176,100 357,900 287,700 644.200 57,600 66,500 74,600 232,200 69,200 113,100 936,700 294,300 479,300 224,000 955.700 412,400 488 503 506 542 454 510 530 544 532 466 416 329 344 443 500 394 298 73,800 85,100 86,200 91,000 60,900 86,400 87,800 90.300 87,500 77,700 49,200 12,300 42,700 69,300 82,900 17,800 2,900 Total Average 32.675,600 1.815,300 28.984,500 1,610,300 219,800 12,200 25,010,400 1,389,500 3,530,700 196,100 442,500 24,600 3,4)5,500 189.700 484 61,400 THE CONTROL OF FLOODS BY RESERVOIRS. 137 VOIR ON SAN JOAQUIN RIVER. AND POWER YIELD FLOOD CONTROL Carried out on a Daily Basis. mary, see Table 10a, page 342.) Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P.P. =0.80. Flood control, holding maximum reservoir space required (rain-water floods 133,000 ac.-ft., snow-water floods 177,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Friant — rain-water floods. 1 0,700 sec-ft; snow-water floods, 14,200 sce.-ft. Stage of reservoir at beginning of year in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) 1,800,000 1,800,000 1,800,000 1,800,000 1,676,500 863,300 1,800,000 1,800,000 1,800,000 1,800,000 1,800,000 1,336,800 1,320,700 1.576.000 1,800,000 1,800.000 744.200 1,387,600 Evapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet .Average power head through period of operation in feet Average power yield in kilDwatts (Load factor= 1.00) Year 797,100 98,400 661,100 244,900 703,100 40.300 51.000 609,300 465.800 555,600 413,800 199,000 48,700 87.600 86,300 545.700 335,700 56,500 13,700 16,500 10,000 19,300 10,000 100 17,500 16,700 18,000 16,500 11,300 4,900 2,400 5,600 13,800 14,900 1,100 2,600 1,699,100 1,833,000 1,848,200 1,847,100 1,494,600 1 832,100 1,823,000 1.862,900 1,815,900 1,662,100 1,100,500 420,900 1,361,500 1,664,900 1.800.000 313,900 111,400 724,500 377.500 1,237,600 497,400 258,400 852,100 169,500 91,400 4,200 U 123.500 936,700 463,200 479,.300 224,000 1,055.800 412,400 488 488 496 536 454 495 503 522 498 423 357 329 344 431 473 378 298 73,800 83,700 83,900 90,600 59,900 85,000 s-'.eoo 89,000 83,700 64.600 35,500 12,300 42,700 68,200 79,000 10.100 2.900 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 28,705 100 1,594,700 200,900 11,200 24,491,100 1.360,600 4,208,400 233,800 4,200 200 3,694,900 205,300 467 58,300 Total .\verage 138 WATER RESOURCES OF CALIFORNIA. TABLE 11. TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. SUMMARY OF WATER AND POWER YIELD BY YEARS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 9 and 10. (For correspHDnding monthly summary, see Table 11a, page 352.) Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P.F. = 0.80. Year Without flood contro Coordinated with flood control by reservoir operating diagram Maximum controlled tiow at Friant — rain-water floods, 10,700 sec.-ft.; snow-water floods, 14,200 sec.-ft. Maximum reservoir space required — rain-water floods, 133.000 ac.-ft.; snow-water floods, 177,000 ac.-ft. Flood control, holding maximum reservoir space required (rain-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Friant— rain-water floods. 1 0,700 sec.-ft. ; snow-water floods, 14.200 sec.-ft. Irrigation draft in acre-feet (no deduction for down- stream prior rights) Deficiency in irrigation supply in acre-feet Average power yield in kilowatts (Load factor = 1.00) Irrigation draft in acre-feet (no deduction for down- stream prior rights) Deficiency in irrigation supply in acre-feet Average power yield in kilowatts (Load factor= 1.00) Irrigation draft in acre-fett (no deduction for down- stream prior rights) Deficiency in irrigation supply in acre-feet Average power yield in kilowatts (Load factor= 1.00) 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1,800,000 1,800,000 1,800.000 1,800,000 1,686,900 863,300 1.800,000 1,800,000 1,800,000 1,800,000 1,800,000 1,505,700 1,320,700 1,576,000 1,800,000 1,800,000 844,300 1,387,600 113,100 936,700 294,300 479,300 224,000 955,700 412,400 73,800 85.800 91.100 91,900 60,900 86,600 88,700 93,500 88,100 77,700 49,200 12,300 42,700 69,300 82 900 17;800 2,900 1,800,000 1,800.000 1,800.000 1,800,000 1,686,900 863,300 1,800,000 1,800,000 1,800,000 1,800,000 1,800,000 1,505,700 1,320,700 1,576,000 1,800,000 1,800,000 844,300 1,387,600 113,100 936,700 294,300 479,300 224.000 955,700 412,400 73,800 85,100 86.200 91,000 60.900 86,400 87.800 90,300 87,500 77,700 49,200 12,300 42,700 69,300 82,900 17,800 2,900 1.800,000 1.800,000 1.800,000 1,800,000 1,676,500 863,300 1,800.000 1,800,000 1,800,000 1,800,000 1,800,000 1,336,800 1,320,700 1,576.000 1,800,000 1,800,000 744,200 1,387,600 123,500 936,700 463.200 479,300 224,000 1,055,800 412,400 73,800 83,700 83,900 90,600 59.900 85,000 84,600 89.000 83.700 64,600 35.500 12,300 4:,700 68.200 79.000 10,100 2.900 Total Average 28,984,500 1,610,300 3,415.500 189,700 62,000 28,984,500 1,610,300 3.415,500 189,700 61,400 28,705,100 1,594,700 3,694.900 205,300 58,300 San Gabriel Reservoir on the San Gabriel River. The ' ' Coordinated Plan " * in southern California contemplates the construction of reservoirs on all streams of suitable terrain for joint operation in controlling floods and conserving water now unused. It provides on each stream, to the extent desirable and to tlie extent that physical conditions permit, for tlie coordination of flood control with irrigation and municipal supply through both surface and underground storage. It i)r()p()ses, whorevcr possible, that flood control be coordi- • See Bui. No. 12, "Summary Report on the Water Re.«iourccs of California and a Coordinated Plan for their Development, " Division of Engineering and Irrigation, State Department of Public Works. THE CONTROL OF FLOODS BY RESERVOIRS. 139 iiatecl witli the charging of the undergroiuid basins, from which such a large part of local supplies are obtained, with practically the entire unused seasonal run-off. The irregularly occurring flood waters would be reduced by surface reservoirs to flows of a workable size for intro- ducing into the subterranean basins but the principal storage of water for equalizing the intermittent run-off would be in the large natural underground basius on the lower reaches of the streams wherever they are available. In their natural state, flood waters rusli down the chan- nels in volumes too large for complete absorption by the underground basins even with extensive spreading Avorks. By reducing these flood flows through reservoir control, practically their entire volume may be introduced into the underground basins either through absorption by the natural stream channels or by artificially prepared spreading works. This water may then be pumped from wells penetrating the subter- ranean basins at such times and for such purposes as necessity demands. It is available for useful purposes in the same way that most of the local .supplies in southern California are now obtained. In some instances, it may be a matter of economy to take part of the additional water made available through the construction of surface storage, directly from the reservoir without incurring the expense of sinking it underground and pumping it out again. Reservoir operation under the "Coordinated Plan," therefore involves all or in part, the control of floods, the temporary storage of flood water to be released later at a convenient time and rate for sinking underground, and the equaliza- tion of some of the run-off' between seasons for an independent surface supply. A description of this plan for southern California is con- tained in Bulletin No. 17, "The Coordinated Plan of Water Develo])- ment in Southern California." The method devised by the "Coordinated Plan" for operating sur- face reservoirs in southern California in order to secure the greatest use of their capacity for both flood control and conservation is illustrated in the following pages. The San Gabriel River is employed for this purpose through the exemplary use of the San Gabriel reservoir. This river, in having the longest record * of daily flow, is found to be the most favorable of large southern California streams for an analysis of the characteristics of flood floAV and is so used in the previous chapters. The San Gabriel reservoir extends up the east and west branches of the San Gabriel River from its dam site which is imme- diately below the forks and eight miles up the canyon from tlie edge of the valley floor. The reservoir is proposed for construction by the Los Angeles County Flood Control District. Since, at the time of preparing this text, the desirable capacity for this reservoir is still under discus- sion, two capacities are employed in the illustrations, one 180,000 and the other 240,000 acre-feet. These correspond to dam heights of 383 and 425 feet, respectively. Capacity as large as these is not necessary for flood x)rotection alone. The removal of the flood menace requires only that flow be limited to an amount that will pass down the river channel without endangering life or inflicting serious property damage. Flows exceeding 10,000 * The Santa Ana has a record almost as long as the San Gabriel River, but part for the 1916 flood is missing. This makes it less suitable for the purpose at hand than the San Gabriel River since 1916 is the largest flood year of the period of measurement. 140 WATER RESOURCES OF CALIFORNIA. second-feet * liave passed to the ocean without serious difficulty within the last several years. Exclusive of s))ace that should be i)rovided for the accumulation of silt and debris, the limitation of floods to 10,000 second-feet requires only 75,000 acre-feet of reservoir capacity. Simi- larly, 52,000 acre-feet is sufficient to limit flood flows to 15,000 second- feet (see p. 61). Capacity in excess of these amounts, employed for limiting floods to more convenient sizes, is essentially useful in con- .serving water that would otherwise waste into the ocean. It makes possible the sinking of greatc^r portions of the total run-off into the underground basins than could be done with flows as large as 10,000 or 15,000 second-feet. The illustrations herein, limit flows to 1900 second-feet, an amount that, it is believed, can be sunk conveniently into the large subterranean basin underlying the San Gabriel Valley. A rule for operating a reservoir on the San Gabriel River that will limit floods to 1900 second-feet, is developed in the previous chapters of this volume. It is expressed on Plate XXI, "Reservoir Operating Diagram for Controlling Floods on the San Gabriel River." p. 88. It would limit floods at Azusa, including the maximum of record, to 1900 second-feet. The maximum flood of record on the San Gabriel River occurred on January 18, 1916. and discharged 40,000 second-feet. To limit this and even larger floods to 1900 second-feet, requires the reservation at times of a maximum space for flood control of 181,000 acre-feet. The use of the operating diagram on Plate XXI for controlling floods by a reservoir as far upstream as the San Gabriel, slightly exceeds the technical limits of its application. If the technical limitations were stricth' adhered to, not more than half the 16 square miles of drainage area below the San Gabriel reservoir but tributary to the Azusa gaging station, should remain uncontrolled since this area may produce floods at long intervals about double the desired regulated flow of 1900 second- feet. However, the only consequence of applying the diagram to the San Gabriel reservoir is that the desired maximum flow of 1900 second- feet at Azusa will be exceeded at average intervals of several decades by the uncontrolled run-off originating downstream from the dam. The probable limit in the rate of flow at Azusa would be about double the desired (|uantity, hut several centuries may elapse between flows iipproacliing such uuignitude. At times of excess flow at Azusa the gates at the dam would he closed if opcn-ated in accord with the reservoir operating diagram. The excess flow would all originate downstream from the reservoir. In using the reservoir operating diagram of Plate XXI for limiting the maximum flow to 1900 second-feet, only 131,000 acre-feet of the total capacity of the San Gabriel reservoir need be employed for this puri)ose. A diagram could be constructed that would employ a greater cai)acity and regulate the flow to less than 1900 second-feet, however, if applied to the San Gabriel reservoir, the desired regulated flow, if made much less than 1900 second-feet, would be exceeded ratlier fre- (juently by the run-off from the drainage area downstream from the dam. If the maximum flood control reserve were increased, say to 160,000 acre-feet, the flow might be limited to 1000 second-feet at Azusa exce])t at the times the drainage area betweei^the dam site and • The crest discharge at Azusa was 8,680 second-feet on March 7, 1918, 22,300 second-feet on December 19, 1921, and 11,600 second-feet on February 9, 1922. THE CONTKOIi OF FLOODS BY RESERVOIRS. 141 Azusa produce.s a oreater amount. This might occur every few years but the accumulated duration of flows in excess of 1000 second-feet would be reduced and less effort would be required in sinking the water into the underground basin. However, since it is believed that flows approximating 1900 second-feet may be made to percolate into the underground basin at a cost small in com})arison with that of 29,000 acre-feet of additional reservoir capacity, 1900 second-feet was selected as a suitable regulated flow for illustrating the principles of coordinat- ing flood control and conservation in the same reservoir. The reservoir operating diagram, in addition to securing the control of floods through the reservation of adequate space at all times for temporarily detaining excess flow that might occur under the circum- stances then existing, accomplishes the storage of water in amounts varying with the season. Through holding in reserve only the space required for the control of floods that may occur under existing circum- stances and releasing this reserve immediately as the possibility of its need for flood control has passed, run-off may be stored in the part of the maximum flood control reserve not required at that time for flood control. In this way during many seasons, considerable volumes of stored water are accumulated without the use of reservoir space other than that included in the maximum flood control reserve, and tliis is done without jeo])ardizing the certainty of the control effected. The water so stored may be draw^n from the reservoir at whatever rate and time desired during the season of its detention. Should it be held into the next flood season, it is subject to release as flood control water if the space occupied by it is needed in the flood control reserve. Where the reservoir capacity exceeds the maximum flood control reserve required by the diagram, as in the illustrations herewith, the excess capacity may be employed either for the seasonal or over-year storage of water. If employed for seasonal storage, its yield will be of the same character as the water stored seasonally in the unused part of the maximum flood control reserve and will augment the (piantity of stored water available in irregular amounts from season to season. If employed for ovei'-year storage, its yield may be drawn from the reservoir in uniform amounts through all .seasons and so constitute an independent surface supply that does not require auxiliary sources during seasons of deficient run-oft'. Thus the yield of reservoirs under the ''Coordinated Plan" may be divided into three parts, namely, the variable flow of limited size that occurs during the winter and spring months as a result of the flood control operations, the seasonally stored water that may be drawn from the reservoir at any desired rate and time during the summer and fall of the year of its detention, and the flow equalized between seasons that may be drawn off at a uniform rate year in and year out. The yield of the first class, in passing down the channel in flows of limited size but at the time of natural run-off, is controlled in volume of flow only, while that of the second and third class, in being stored water, is controlled both in time and volume. The yield of all three classes is useful. The fir; t, arriving in the winter and spring in flows of limited si/.e, may be sunk undefgi-ound as it occurs. The second, in being stored water, may be drawn from the reservoir as convenient either for sinking underground or for supple- menting surface supplies. It being of irregular amount from season 142 WATER RESOURCES OF CALIFORNIA. to season Jiiid in some seasons tluTc ])t'in<»' none at all, tlie yiekl of the second class can not become an indc])eiiSan Gabriel reservoir under several modes of operation. In these tests it is assumed that the reser- voir was in existence at the beginning of the period and was operated through the succeeding 30 years as described in the several instances. The destruction of reservoir capacity by the accumulation of silt and de])ris is neglected and the first 152 second-feet of natural flow are l)assed for ])rior rights. The water passed for prior rights in all modes of reservoir operation and for all reservoir capacities constitutes 40.5 per cent of the total surface run-oif of the i)eriod of analysis. The application of the reservoir operating diagram hei'ein described to the daily flows throughout the oO-year period of record, results in the average yield on the part of the maximum flood control reserve which is the first l:n.000 acre-feet of capacity, of 37.100 acre-feet per season during the winter and spring months in flows controlled to less than 1900 second-feet and of 36.700 acre-feet i)er season in seasonally stored water that may be drawn from the reservoir as desired within the year of its detention. These yields are 29.6 and 29.2 per cent respectively of the average run-off for the period. Some water is stored in 27 of the 30 seasons analyzed but in no season is the entire 131,000 acre-feet filled. The nearest to filling is in 1907 when 110,300 acre-feet are held in storage. This reservoired water, in being stored witli facili- ties required to secure the desired limit to flood flows of 1900 second- feet, is held without extra expense. Together with the winter and spring controlled flows resulting from flood regulation, it constitutes the entire run-off from the San Gabriel watershed tributary to Azusa, with the exception of the water passed for prior rights and evaporated from the res(M"voii" surface. Wifli a capacify of ISO.OOO jicre-feel, the space in excess of the maxi- mum flood control resei-ve (131,000 aci-e-feet), if employed for seasonal storage in conjunction with flood control, would convert 17,400 acre- THE CONTROL OP FLOODS BY RESERVOIRS. 143 feet of tlie average winter and sprino- yield in controlled flows of the maximmn flood control reserve, into 17,100 acre-feet of seasonally stored water. On an average about 300 acre-feet per season would be lost by evaporation in doing- this. Similarly, with a capacity of 240,000 acre-feet, the space in excess of the maximum flood control reserve (131,000 acre-feet) would convert 28,800 acre-feet of the average winter and spring yield in controlled flows of the maximum flood con- trol reserve, into 28,400 acre-feet of seasonally stored water. About 400 acre-feet per season would be lost by evaporation on the average in doing this. These yields are 13.6 and 22.6 per cent respectively of the average run-off of the 30-year period. Thus, in a capacity of 180,000 acre-feet, the 49,000 acre-feet additional to the maximum flood control reserve would convert on an average 17.100 acre-feet of yield controlled only in volume, to yield controlled both in time and volume or one acre- foot for each 2.9 acre-feet of storage capacity. In a capacity of 240,000 acre-feet, the 60,000 acre-feet additional to 180,000 acre-feet, would similarly convert on an average 11,300 acre-feet per season from flow controlled, only in volume to flow controlled both in time and volume, or one acre-foot for each 5.3 acre-feet of storage capacity. If the capacity in excess of the maximum flood control reserve of 131,000 acre-feet were employed for over-year instead of seasonal storage in conjunction with flood control, a uniformly continuous supply of 22 second-feet or 15,900 acre-feet per season could be drawn from a capacity of 180,000 acre-feet. Similarlj^, a uniformly con- tinuous supply of 32* second-feet or 23,300 acre feet per season could be drawn from a capacity of 240,000 acre-feet. These yields are 12.7 and 18.6 per cent, respectively, of the average run-off of the 30-year period. In both instances this Avater would be derived from the winter and spring controlled flows and the seasonally stored water of the maximum flood control reserve. Thus, in a capacity of 180,000 acre- feet, the 49,000 acre-feet additional to the maximum flood control reserve w^ould convert 3300 acre-feet per season controlled only in volume together M'ith 14,000 acre-feet controlled both in time and volume but not equalized between seasons, into 15,900 acre-feet per season controlled both in time and volume and equalized between the years, or one acre-foot per season brought under complete control for each 3.1 acre-feet of additional capacity. On an average about 1400 acre-feet per season would be lost by evaporation in doing this. In a capacity of 240,000 acre-feet, the 60,000 acre-feet additional to the 180,00() acre-feet would similarly convert 11,600 acre-feet per season controlled only in volume into 10,600 acre-feet per season controlled in both time and volume, of which 7400 acre-feet per season would be equalized between seasons, or one acre-foot per season brought under control as to time for each 5.7 acre-feet of additional storage capacity. * In the analyses of reservoir yield for the period of measured run-off, Tables 13 and IZa, a yield of 41 second-feet continuous flow is obtained from Jan. 1, 1897, to Oct. 1, 1926, with a draft of 61,300 acre-feet on water stored in the reservoir prior to the beginning of the period. At the time of making the computations, it was thought that the rainfall of the seasons just prior to Jan. 1, 1897, would yield this extra water .so that 41 second-feet would be the long time average yield; how- ever, subsequent detail study of rainfall records indicates that it is improbable that so large an amount of extra water would have accumulated during the seasons just prior to 189 7, but, sufficient would probably have accumulated to increase the yield considerably over that for the exact period of analyses. The exact yield in con- tinuous flow for the period Jan. 1, 1897, to Oct. 1, 1926, is 32 second-feet or 23,300 acre-feet per season. 144 WATER RESOURCES OF CALIFORNIA. On an averafro about 1000 acre-feet per season would be lost by evap- oration in (loinp: this. The three following tables summarize the yield of 180.000 and 240.- 000 acre-feet of capacity operated in accordance with the "Coordinated Plan" and compare it with the yield of the maximum flood control reserve if not employed in conjunction with additional capacity. The first two tabulate the averapre run-off divided between the yield in prior rights water, controlled flows resulting from flood regulation, seasonally stored water, continuous uniform flow equalized between seasons by over-year storage, and evaporation loss from the reservoir surface. The first table assumes that the space in addition to the maximum flood control reserve is employed for seasonal storage in conjunction with the flood control ojierations and the second table for over-year storage. The third table further segregates the yields of the first two tables according to the size of total flows passing Azusa. Still further detail is printed in the tables of yearly summaries at the end of this section and in the tables of monthly summaries in Chapter YIII. The actual computations were carried out on a daily basis to meet the requirements of the reservoir operating diagram which calls for a daily adjustment of reservoir level during the flood .season. The daily computations are too voluminous to place in print. It may be observed on reviewing the three following tables that the juaximum flood control reserve, without additional capacity, controls all floods and renders the entire run-off of the stream, except for 0.7 per cent loss by evaporation, available for sinking undersrround. It yields 29.2 per cent of the average run-off in seasonally stored water but does not create an independent surface supply. The two larger capacities employed for flood control and seasonal storage, control all floods and render the entire run-off, excejit for slightly larger evapora- tion losses, available for sinking underground. However, a larger frac- tion of the average run-off is made available as seasonally stoi-ed water. The two larger capacities convert 42.0 and 51.9 per cent, respectively, of the average run-oft* into seasonally stored water instead of 29.2 per cent, the yield of the maximum flood control reserve without addi- tional capacity. In so rloing the two larger capacities do not conserve more water but rather make larger portions of the average run-oft' more conveniently available. When employed for over-year storage in con- junction with flood control, the two larger capacities still control all floods and render the entire run-off of the stream available for sinking underground if desired, but 12.7 and 18.6 per cent, respectively, of the avei-age run-oft' is in a uniformly continuous yield suitable for direct diversion from the reservoir for municipal juirjioses. The losses by evaporation from the reservoir surface are l.S and 2.6 per cent, respec- tively, in doing this. In all instances 40.5 per cent of the average run-off passes the dam to satisfy downstream prior surface rights. In size of total flow passing Azusa, the maximum flood control reserve yields 66.4 per cent of the average run-off in flows of less than 500 seeond-feet and 78.5 per cent in flows le.ss than 1000 second-feet. The two larger capacities of 180,000 and 240,000 acre-feet, employed for flood control and seasonal storage, yield S5.7 and 93.5 per cent of their water, respectively, in flows le.ss than 1000 second-feet. Employed for flood control in conjunction with over-year storage, 180,000 acre- THE CONTROL OP FLOODS BY RESERVOIRS. 145 feet of capacity would yield 74.8 per cent of the averao'e run-off in flows of less than 1000 second-feet. Had a reservoir operating diagram been constructed to limit flows to 1000 second-feet instead of 1900, as in the foregoing illustrations, its maximum flood control reserve of 160,- 000 acre-feet would yield over 99 per cent of the average run-off in flows of size less than 1000 second-feet. For a total capacity of 180,000 acre feet, the division of the yield into controlled flows and seasonally stored water, however, avouUI be diff'erent, the amount of the seasonally stored water being less. 146 WATER RESOURCES OF CALIFORNIA. AVERAGE WATER YIELD OF SAN GABRIEL RESERVOIR UNDER "COORDINATED PLAN." FLOOD CONTROL AND SEASONAL STORAGE COORDINATED January 1, 1897 to October 1, 1926 (For yearly values, see Table 12, page 158.) Maximum flood control reserve or first 131,000 acre-feet of capacity 1 80,000 acre-feet capacity 240,000 acre-feet capacity Item Acre-feet per season Per cent of average seasonal run-off Acre-feet per season Percent of average seasonal run-off Acre-feet per season Per cent of average seasonal run-off Passed by dam for prior rights (first 152 second-feet of natural flow) 50.900 37,100 36,700 800 40.5 29.6 29.2 0.7 .50,900 19,700 53,800 1,100 40.5 15.7 42.9 0.9 50.900 8,300 65,100 1,200 40.5 Flood controlwaterpassiog Azusa during flood season at rates less 6.6 51.9 Evaporation from reservoirsurface 1.0 Total 125,500 100.0 125,500 100.0 125,500 100.0 THE CONTROL OP FLOODS BY RESERVOIRS. 147 AVERAGE WATER YIELD OF SAN GABRIEL RESERVOIR UNDER "COORDINATED PLAN." FLOOD CONTROL, SEASONAL AND OVER- YEAR STORAGE COORDINATED January 1, 1897 to October 1, 1926 (For yearly values, see Table 13, page 160.) Maximum flood control reserve or first 131,000 acre-feet of capacity 180,000 acre-feet capacity 240,000 acre-feetcapacity Item Acre-feet per season Percent of average seasonal run-ofE Acre-feet per season Percent of average seasonal run-off Acre-feet per season Per cent of average seasonal nin-off Passed by dam for prior rights (first 152 second-feet of natural flow) 50,900 37,100 3b,700 800 40.5 29.6 29.2 0.7 50,900 "33,800 22,700 15,900 2,200 40.5 2fi.9 18.1 12.7 1.8 50,900 '^22,200 1^25,900 1^23,300 3,200 40 5 Flood control waterpassingAzusa during flood season at rates less than 1,900 second-feet 17 7 Seasonally stored water 20 6 Yield in a uniformly continuous 18 6 Evaporation from reservoir sur- face 2 6 Total 125,500 100.0 125,500 100.0 125,500 100.0 "The average yield in flood control water shown in Tables 13 and 13afrom which this summary is compiled, is 34,000 acre-feet per season. In the computations for these tables, the period of analysis closed with 7,600 acre-feet less water in storage than at the beginning. This water, the equivalent of 200 acre-feet per season, entered storage prior to the beginning of the period and was released as flood control water during the first year. Therefore, it is deducted from the average yield in flood control watershown in Tables 13 and 13a to obtain the exact yield for the period of analysis. b The average yield in flood control water, seasonally stored water and uniformly continuous flow shown in Tables 13 and 13a from which this summary is compiled, is 30,000, 13,800 and 29,700 acre-feet per season, respectively. In the computations for these tables the period of analysis closed with 61 ,300 acre-fee* less water in storage than at the beginning. This water, the equivalent of 2,060 aore-feet per season, entered storage prior to the beginning of the period. To obtain the exact yield for the period, a supplementary analysis was made having the same amount of water in storage at the beginning and at the end of the period. This gave the smaller values for flood control water of 22,200 acre-feet per season and for uniformly continuous flow of 23,300 acre-feet per season, and the larger value for seasonally stored water of 25,900 acre-feet pei season, entered herein. 148 WATER RESOURCES OF CALIFORNIA. o b O N o O < > a S z § o o o c o u -o o o en (I c 3 - S u Q z Ci " -H o > a: u (/) . w s; a: 2 ^ bC "O (S U- c >> *J "-H • i'fc E -si" Maximum flood control ri'servc or first i;i 1.000 aere-feet capacity'' c o ia c — t£ c; ill a>— — — = ■£ •D S t) l|| a a a i| li c a o •a o o Flood control, seasonii 1 and over-year storaRC coordinated S 1! >■. £ ^ It HI ill Maximum flood control reserve or first 131,000 acre-feet capacity 1; CS THE CONTROL OP FLOODS BY RESERVOIRS. 149 o o o o o oo ooooooo ooooooo ooooooo sooooo ooooooo »oai CO o ooooooo ooooooo Tj< '^ O I-^ OS ooooooo 03 ■^ oo W3 lO lO Ol ooooooo CO lO oo 00 CO I:^ OS »-< fcO O CO COOO ooooooo OS t>« (M <:c as CO i>- '* « C<1 oot^ ^ ooooooo CO 1-- -^ -O lO b- 1^ r>j CO »o »o 1-H -^ ,-t ^ ^ ^ — » 1-H OS oooooc »o o m o »o ^ ■M in t^ O p. t> QJ ^ rt CJ -£■ '3i2 2-g men a ■>- ss ■-go's §'"' S" S-2 S o. 2 =^ oj ;3 ra .2 CO -ojaS CO.S-" H c ^ ^H o S'C SlgcD"S § c a. t^-"- Mj5 S^'m ?'m OMl9'n03C-g,=|.g~ g-.S |, O' a^ g,.E 3 M.S £ 3 s MScaSoa-^ti MB S rt.2'§ ^'§£3 K « a " a c a ?f a S- s - S ■2 "■? ".S 'S.2 ■^ -a o ~ S o SZ. ! & -2 1:1^ si ii I* O O o"^ O -O . "O'O C3cQC0qC3o^O-*^3^ bO '^ 6tl S M 2 M 2 'm ^5 2 bn-*-* bJD , hC^ bC.2 ^'*-' rt H t-H SH ^H ^W — .S _, o) Tt< -n -a a 150 WATER RESOURCES OF CALIFORNIA. c (t< o u U u *■ 4-> Z < c o CL, -0 o Q o en ■*-> H h bU < 3 m t-i Z s O (^1 CO J2 w o CO o "« ^ U; O Uh <4-l N oi 4-1 o o (/I (0 CO (U -0 C O > 00 o I > C CO CO CO >. 4-> a s u ^ u :j 1— 1 CQ O 13 C > <: w . ic -n- o C 53 U'^ i it o" 60 2 b£' *- ■<** C^l « o t^ o »- > o loa o o a ci « im' — o d c- 1 00 dc d o >> • lO -r o o a C o o o. §g D, ■^ o" c a '- £ -^ oo4? 0-. O C-. (N O (N t> Ci ma: o -»^ floo 3Crv 1,00 paci ._! ,^ i^ ...^ _ ,_i f^ 5 00 d c d o •""" '^ 1 in -)• o S £2 g 3-.- - ^- -e o a g £ sj ■o s Max cont orfi acre-f bli "S 2t; o O C C O w o = > o oc K :r. QO o cr. c; -J3 c^ jt.-- Sc^).--- c O JOI> ^ S o i ^1? C) o'c ■ra" c — m =s ^ ^ * c^ t^ iC e-i o IN " s 'f ' = _o § i ° o ►^ O oo .^ C O oo O OG o oc o 00^ — oocot-a O 1-^1-^ •<5' CO t^ 'J" CI CO so a ■^ oo '- ■a i >> — ' CC O* l>- ii" co" o"— U5 o rt o a --co 1^ >n e-i -3 O C3 OT o O u ^ O O *:« a. S, (M M o C3 "S ooo oooc o oo o o — ^■3 C-1 O C35 CO t~ ■» i w^ 00 00 CO !M 00 t^ - in oc c "^ i >. — 'r^'ic— ' "" CO o — to C3 s S'S — C-l— - t^ lO o C o ^ s T3 "3 o a imum flood rol reserve rst 131,000 eet capacity o o ooo os: o oo o t^ — • ^ O cre <^^_'»■_t-- 1^ oooc o co" o' i^ >o T3 ^^ O Max cont or fi acre-f .^ ^ .£ TS e i g g ^ >o .9 a 3 1 -< Iss 15 2 ■- i: 1 r stage for flood control. Not shown where coincident Af- I Q CC F"P\/A| D -Jfel> for flood control, constant draft of 22 sec.ft and var^ LOLrVUI R JJ?'^e"V° l^^ ^^i'^^k f^"^'^ through Ihe reservoir forDninW rnf)RniNATFn ess of constant draft and water passed for prior rights '*^'^ kyUUnUII>ini LU n Gabriel River near Azusa. taken from records of UniteijSA 1,900 SELC. FT. -- Gabriel River near Azusa, with reservoir operated cof^-^'' ^^^- '^^■ ■00 AC. FT 1 ,1 -Ur^L^^';^'"^^'l-'^'[°'" -'"]> ' yP ♦= successive dates in the; o!l« ™^ aailxrainfal records of United States Weather Bursal FT L J^ h July 1, 1102 to July 1, 1903, February 1905 and March 1909 a oc 'fo?6 „= ... ,„ M. apfl ^ J 8 97^^ tp CI. „ EB , p» 1898 u IP oc .0 .. .1 p.< J A S 99^^ , t« c . t. ., ^J900_ „ . t„ „ . 'l" "' ' TT 1 1 1 1 M M 1 -100- -1 1 L._ 1 1 1 1 M M 1 1 - . F^vgressive rmhV indes-^ fW-nittid l7%*d OjnlTrt dais's. t Slalc-nocduinrntl 1 1 / : i ! ,1 ! 1 1 1 1 i ^. : 1 . ^ SU8t- notJ mirol .,M »„,t.„. ir.fl^ •■:. _ -eo- - - ^ - : * i ^ P "^•'"'•" "•- > '■ s,j"iijr^iis ^^ =i^ F=n = p ^ 4 ■^ 1 L _ F= = ^ 1 = c :; 3S _ — k- ; :: = i - d^ = ^ "h : J = = - = - - = J =i = — - ^ ? = r ^ - = = = = : = = = ~ ^ ^ zz ^^ 3 -20- —0- - - - - _ I - ^■^. L M fL iii ^ u_ ll „, 1 ±j _ Jd !1 ^ z J! Id ij I d d d d - _ I £ d ^ E - 3 " " - : :: - : g ~ - - - : - J t I ^ :: 2 _ ,- d d : t c 1 rr c t ^ „ - - - I - ~ I z I E ~ : I - ~ 3 R f 3 = = I - _ — = i± i= = = = ^ E = ;^ ^ £ ; c £ OCT '?ol^ Dec F« 1913 1914 I9IS ™ ».r j9ie .0 «-, „,. -1 , -4fr ;- " 1 \ 5lF>im fliwrZyM MC.n-«t Jan 18" 1 1 1 Mil "Tl riiiri 1 o 1 1 i 1 1 M 1 iM 1 1 is =L = = = ^ ^ - - 5 - ■v> - - - - - '^r s ii -FlooJ ^ - - - - s " ^ J __l_ ,:;; -( > \ ^ _ : = ^ ^ = _ = t B z E E q ^ - _ _ - - - - - : - - i = i - - - - _ - - - - ^^ ^ ^ - ^ *" B S : ; ; - - FVoire ^ jinfall Indo^ . 1 i i :'■■ rp— - p 2-20 ^ '■■f 1- .•i.-„ ^ i+Tf^n-h - 1 = 1 = 1 ^ T "^ h -1- " - - 1 - r- - - 2 : : : - ; < 2 ~ Tri ^ = .■^ % ^ ' - - - : ~ 1 - = 5 = = = E ^ - - I - ^ "° "" "" " ^ : : 5.. I' ~. 2 ± Jte'!;"™'' - ! 1^ ■i. ^ 1 ^: Ml ■■ ■• jklkl pj -^*l-JUJ 1 1 ill '11 s I ?.« ?o »c P« 19 £ »o ^, ov EC ,. 1922 CT 0. ,^ 1923 «UG CPT OCT OCC N. „ .. , „ J J924 „„ OCT. .>. ifin 'Jl-TL . I ■ " 1 1 1 1 ! 1 1 M " — ~i m r — n ~ ~ " rr ^ p- p r p p P p n p n p 1 n p p n p ~ ~ ~ ~ ~ ^ ~ " ~ "■ "" " ~ 1 -^40- - M M -p- -1- -, _ - -L ~ - _ 5 rum rio. """"•"" \ ^ __ _ ± -^ _ _ Bj _ _ _ _ _ ^ ^ _ _ J _ _ _ _ _ _ _ _ - _ _ ^ - „ - - - - ^ J ^ - ~ - - - - - - - - - H20- ± -i- ^-M^- ^ - - - t -1 - - — L -rl — N - i-*i ^ •4 £= Q P r - - - - p ui «r rfn J^ iL Pr _pi ill - - - - - ^ - - "< - r- — - - - - - - p n - - L - -1 - - - - -1 p - ^ ^ - nr ^ +^ i. ttJ ^ ijXI inn ^ - ^tage -Flood wnrrol = ^ 1 1 u_u = ■ ^ _ S - Jtr ^^ u i^ - - ' ■* ^ ^ ^ ^ ^ ~ E - : ^ $ H - I - - - - " - ,5i.i. nwd ,nl - ' - - - - - - - I - - - - - - - - - 1 - - - - - r -; ^ ^T ^ '"^''Hi1 - nr'^^'ftit 4"i"iT'riiTffi-i- - - b "Pfl ni IT 1 _ = = - - - ~ ~ - ~ ~ ^ ~ - ~ ^^i-i^ I ~ zz ~ ~ ~ - ~ = - : " s "= T = f ^ "Z 2 3 M ^ - - g ffl ^ = - I ± J : - X - i^ipT ['l.VIK NXVI. M 1 1 1 1 1 ■ ' . X ~r TTl" r^'i n Tr TT ' lllWW \ ■■ 1 "■± ^ " —L S„(,.n^i^r,< 1 •.. ' ; 1 A M 1 M -j !-'-' m^' Sra^-flMdwnlrol f 1 : 1 lA! , _;" ,"|""|",' 1 1 1 1 1 [ 1 i . "'^ ■•-:J"'..5j^rT^r 1 i C-s[:;44-E ..I, o«. «t j.« re U «■...! 1917 .»t. „„ Oct, NOV. Die *N Fte. MAR APRIL 1918 AUG fPT OCT ov IC AK. FEB MAR ARRIU I9IS ULY AUG. BCrr, T KOV ri. «. p.... MA I920 AUG, SEPT e " T 1 1 IF 1 1 ', . I 1 1 1 1 1 Ml! MM ™'S L.0- II 1 II h-l 1 J :'- /ProgreMive rainftll m u it n . rimftll i»).^ .. -^-^ LL J It ' - _ . r '^ i_ -- _- -- ^ 5t.8,-FloMton = SSi % ^i^ ;-Tf-" Stafii-nwdc ^ 4::: fffffi =UJ. -r- t ■ — T^ h" 1 i: -lU- Mill I — -^: I— -- -'^ P P ^-Tr--ji 1 1 'sT X 1 ["\'\ 1 4i ; '■■''■■'■■■j+''' ^: j- xt _i^ F~-- 1 _- :■-■ ■■■-;■•-■■ j. ».„R,„ 4-! 1 1 1 i . r ■ ,\r r» "1 I^ , ! — -1- 1 a ' ij >25 U_J .... ...I! 9 26. U_L ■^ — ' ■ — —^ "■^ ~~ JHh ;!Ss:''CTir£*Kf* iSSSWf,.'.: Effect of Controlling San Gabriel River Floods stage of san gabriel reservoir FLOOD CONTROL AND CONSERVATION COORDINATED THE CONTROL OF FLOODS BY RESERVOIRS. 153 Monthly and yearly summaries of the computations from which the foregoing tables were prepared have been assembled, together with summaries of other comparisons made in studying various modes of reservoir operation. The yearly summaries follow herewith but the monthly summaries, because of their bulk, are placed in a separate chapter. Included in these is the test of 180,000 acre-feet reservoir capacity operating as proposed in the "Coordinated Plan" except that, instead of employing the reservoir operating diagram to grade the flood control reserve in accord with current necessities, the maxi- mum amount of 131,000 acre-feet was held empty until April 19th, tlie close of the flood season. With over-year storage, this change reduced the average yield in seasonal stored water from 22,700 to 3000 acre- feet per season, a reduction of 87 per cent. It also reduced the yield in uniformly continuous flow from 15,900 to 13,000 acre-feet per season. Floods would have been limited to 1900 second-feet just the same. In addition to the water yield, these computations furnish informa- tion upon the reservoir stage under the several conditions of operation. Plate XXVI, "Effect of Controlling San Gabriel River Floods upon the Stage of the San Gabriel Reservoir," delineates the reservoir stage day by day from 1896 to 1927 for three conditions of operation repre- senting three steps in coordinating the several uses of 180,000 acre- feet of reservoir space ; first, operating for flood control alone by the reservoir operating diagram, second, operating for flood control in combination with a constant draft from over-year storage, and tliird, completely coordinating the usefulness of the reservoir space by operat- ing for flood control, a constant draft from over-year storage and a variable summer draft from seasonally stored water. Plate XXVI assumes that a reservoir of 180,000 acre-feet capacity was in existence in 1896 and operated through subsequent years in accord successively with each of the three conditions of operation above mentioned. The volume of water in storage expressed in acre- feet is shown on every day of the 30-year period by the vertical position on the reservoir space scale, of lines extending across the plate in several rows. The top guide line of each row represents a full reservoir and the bottom line an empty reservoir. The space between each pair of horizontal guide lines represents 20,000 acre-feet. The light red line delineates the reservoir stage were it operated for flood control alone by releasing water only as required by the reservoir operating diagram. The heavy black line delineates the reservoir stage were it operated for flood control and a constant draft of 22 second- feet from over-year storage. The heavy red line delineates the reservoir stage were it operated coordinately for flood control, a constant draft of 22 second-feet from over-year storage and a variable summer draft from the seasonally stored water. Below the reservoir stage lines in each row is shown in a light black line to a special scale superimposed upon the reservoir stage scale, the unimpaired flow of the river at Azusa and in a light red line, the flow as controlled by the coordination of flood control, seasonal and over-year storage. A line of black dots shows the daily value of the progressive rainfall index used in entering the reser- voir operating diagram to determine the necessary flood control reserve. The following table shows the average size of the total flow passing Azusa for the three steps in coordinating the use of reservoir space described above. 10— &2411 154 WATER RESOURCES OF CALIFORNIA. ^ 3 ^ ^ 3 m •0 .. (0 CO '""' rt w C iJ cd X U Flood control completely coordinated with conservation Reservoir emptied each summer to a level that would maintain constant draft through critical period, con- stant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram "Coordinated Plan" Hi 19,790 16,680 4,600 1,290 1,500 660 5 O Constant flow from over-year storage in acre-feet per season o oo oooc 5 O Seasonally stored water released as a variable summer flow in acre-feet per season'' oooo o oc o_-oS 3 3 O 5 IN ■<■ 190 1,340 1,380 1,250 1,550 650 1 CO Flood control partially coordinated with conservation Constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram •SIS 111 15,160 2,350 3,240 3,400 3,510 2,330 3 O 1 C-1 Constant flow from over-year storage in acre-feet per season oooo ooc eo en -^i* O 00 Tj. c^ oo_^H ,~t ,-1 ir 1 CO Seasonally stored water released as a variable summer flow in acre-feet per season oo o oooc > o Flood control water and waste over spillway passing Azusa at rates less than 1,900 second- feet in acre-feet perseasonbe 300 2,100 3,100 3,300 3,4,30 2,290 o CO Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Jig ^ S, 740 2,870 3,820 4,200 4,000 2,750 o o o" Seasonally stored water released as a variable summer flow in acre-feet per season oooo o oc o Flood control water and waste over spillway passing Azusa at rates less than 1,900 second- feet in acre-feot per season" ' 740 2,870 3,820 4,200 4,000 2,750 o o o" o 1 o o i o l 1 I THE CONTROL OF FLOODS BY RESERVOIRS. 155 3 •-■ O « O O O M .2-0 0)T3 t" ^■1 I tie „; Ul •-. WZ m .S-S.SS .SS - -O'S^ o « g.'S'"' =5 fc <^ s "*^ G ■*^ c3 <».— a) a> .s|.s| g ^ g J •a3 Dcd &5 i 4J 55 cj o ^ ^ ^ o -.J *^ fc- o — ^iii S bo K^ « ''^ g "T ■-, .S M > b£0 o— -.2 S'^ ?!-=^ E-oS S^"? S c^ O ^ ^ !>." -i ■s e^.s-ag^-' C CO o 5 S 01"° " oT-O ->^ S m "= " ° -2 ^ g £ c «-n ^■E:r c:- o ^-c M '^H m o'S M'm "■;;; [„ o 3 bo 3 hr.^ c3 xi br 2j 2 3 £ —r^OO "i a|sg|ai&:ag3g"-s3 i;^"-^ " &■- 2 2 c eg c^S «-o ■^ H-i^ ■ >.'2-~ J SI 5'2;-2 3^-S-S'>.rt-S n-g t,- •iS£J:oi^ib^JgfJfi? H^H^ >H.2j=H «H «^ g^ ^ 3-° .>; a .& a S S i o 3 S 3H ^. "1 2 THE CONTROL OF FLOODS BY RESERVOIRS. 157 SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. Tables of Yearly Summaries of Water Yield Computed on a Daily Basis. Showing the effect of coordinating flood conti'ol ana conservation. (See Chapter VIII for corresponding monthly summaries.* ) Table 12 — Yield under "Coordinated Plan," flood control and seasonal .storage coordinated. Capacity 180,000 and 240,000 acre-feet. Tablk 1.3 — Yield under "Coordinated Plan," flood control and seasonal and over- year storage coordinated. Capacity 180,000 and 240,000 acre-feet. Table 14 — Average size of flows under "Coordinated Plan." Capacity 180,000 and 240,000 acre-feet. Table 15 — Comparison of yield for two methods of flood control. Flood control coordinated with seasonal ana over-year storage. Capacity 180,000 acre-feet. Table 16 — Comparison of yield for three steps in coordinating the use of reser- voir space. Capacity 180,000 acre-feet. Table 17 — Comparison of yield operating for flood control and constant draft only. Capacity 180,000 and 240,000 acre-feet. Table 18 — Average size of flows for throe steps in coordinating tlic use of reser- voir space. Capacity 180,000 acre-feet. ♦Monthly summaries not prepared for Table.s 14 and IS. 158 WATER RESOURCES OF CALIFORNIA. o; C m > Q u H z 03 d O o •o a: (0 *-* z 9 '3 to a S 3 U C8 P9 J O u a H o « < Cu o C8 —" •c '^ 7, c o ax "SI CS < ^ o 3 TJ 'C C8 n C/3 § a: IS (J y o > u 'y o 05 fTl :: Z ^ o W <3 CO 4-> £ CO >> o « a; Q w 3 r « z w a c o £ c «-< 73 2 S o U (41 > Wi H c o a c/5 o 73 C O o u w ^ (33 u CO o o o S"^ r» £ CT^ CS 7, 5 o CS CS (0 3 < 11 93.348 18.609 10,463 11,976 99,570 22,314 106.985 26.836 164.715 233,860 352,890 Evapora- tion from reservoir surface in acre-feet 1.081 190 1,178 61 1,263 174 1,818 2,423 3,238 Seasonally stored water in acre-fcct 39.304 2.732 47.822 437 55,685 2,482 100,310 163,981 246.672 ■§ o c o passing Azusa during flood season at rates less than 1.900 second- feet in ooo oooooooo p" -T3 1 by dam for prior rights (first 1.52 second- feet of g.S i 11,076 50,570 21,816 50,037 24,180 62„587 67,456 82,808 Is Hi 93.348 18,609 10,463 11,976 99,570 22,314 106,085 26,836 164,715 233,860 352,890 Evapora- tion from reservoir surface in acre-fee t ],081 190 1,178 61 1,263 174 1,818 2,427 2,077 Seasonally stored water in acre-feet 39.304 2,732 47,822 437 55,685 2,482 100.310 161,113 187,233 -a o 1- 5 1 passing Azusa during flood season at rates ^§ o c 2,864 80,172 J by dam for prior rights (first 152 second- feet 0^ -Hi k 52,963 15,687 10,463 11,076 50,570 21,816 50,037 24,180 62,.587 67,456 82,808 o if 5! a. S II 93,348 18,600 10,463 11,076 99,570 22,314 106,085 26,836 164,715 233.860 352,890 Evapora- tion from reservoir surface in rt 984 190 589 61 1.156 174 1.460 2,029 2,178 Seaaonaliy stored water in acre-feet 34,488 2,732 15.717 437 49,747 2,482 70,682 120,438 138,732 o B O water passing Azusa during flood season at rates less than 1.900 second- feet in a 4,913 32,694 6.045 29,996 43.937 129,172 Passed by dam for prior rights (first 152 second- feet of 3 B S " 52,963 15,687 10,463 11,976 .50,570 21,816 50,037 24.180 62,587 67,456 82,808 h- OO Oi O — CI CO -^ »0 to t'. CiOJCiOOOOOOOO OOOOOOO^OCliO^C^O^Ci^ THE CONTROL OF FLOODS BY RESERVOIRS. 159 OO'^OOCOOOCOh-O'^'-'U^OiCCCOC) lOoooootMM— "O'^oO'^r-'icxO'— «occcoOCSlcDC01>-0000iC^-C»C»000Cm0i'rt«rt^ C^'^w'tcTcc cToi i—Tio'i-rt^t^OO^C^'cD »0 iO CO l-^ I--COCOI— t^ioc coc»oocoeO'-000000 rf^COCOtMcO':OI:--( ■^ o '— ' — ' "^ tyj »o »o » -*»**cocor-coi>.cx)0 fh-CO— 'GOO^'— 't^Cvi -_ OO O 0_ iO M »0 GO CO_ >" GO t^ O "tJh" t-T ^ lO ^ O ■^ t^ t-^ t-- f;© lO CO o »o oo »o c CO oo CO o" oco-^c^ocooocor-o-^'-'c )i-ic>"rj400Tt*r-cDT-.c t'- CO CO !>• t^ »0 ~ ^cooo CO CO — — r (M <-l (M r-. -H T-. c t*-ti !•- OC C^ •— CD 00 T^ -^ O < — 'O0t--C-J»0>— '— cc^o- CD o"d »o »o oi'^-T'-TTir^ira' t— rGoco''--r r-Tio OOC^ I— Tj^iO'-'CO lO'-HC 758 243 272 339 oot--cot--t^woot- iC^OOO I--- C-l -r}« CD -t^ O GO -rf lO OO ■^ ^ CO OiCOO 05 00 lOOO coo cot^-- lO <-« »o "^ r-t CO cr- -H gb* 444 101 518 413 362 CD^t^ cm u 2 PQ o z <: z o a; o > w CO S ►J u I— c a; CO <: O z c/) a 9 o H s •1 •(-> iri 4-> >> 3 r, a, s o u «4-l r n T) >> r )h n a 3 S 4J « 05 z es 4) o CO (0 13 c o CO CO w ce o 73 a S , 2 o 1 u o CM 101,526 48,529 42,596 43.325 82.358 52.757 81.668 55.102 95.190 ll ill-sl M^^rr ^^^*M CI — ex CO rH > ll V (A u <^^(^4c■1(^^<^^MCsl'^^c^i CO O CO CD_ CD eO cO_ t^ O O Cs OS C^ C^ cH Ci d^ C^ ii IS s 3i ODCaeOcOO'^iCcDtO -^ocor^r^^-ooco-^ CO CO Tt'^ Cl_ to CO CS oo »^^ CO 00 O -^'" CtT ci" CD co' -*•" en ^ — . ^ C-- CI O CI -J o o ||i|ls| -^OOOCS — CD-^O OO Ci OO CD to t^ »C c?s -- to — -^ T^ 3 r^ O ^ ^ =)vi^ q3 H I- C'^ -^ CO Sia « O «« ooooooooo 1 ooc^oot^r^t-caci 00 CO •-H CO ^ oo oo ■^cf »o crTcTo CO ^ -* t^ •0 1 4^ eoooo-^otooco — ' C^ -^ Oi o_ co__ o_ c>_ ii«" cf CD oT CO CM i •a 08 ftHj3_o "-ja «>- c«3 « COt^COcDOcOt^Ot- CDOO-JDr^t^— tPOOOOO crcD-^otoooo — to cT »o" o — o — ' o' -«■ CI lO 1— . —. w to CI lO CI CD 1 r^oooao-^e^co'^io OJOSOOOOOOO oo oo 00 Oi OS o> oi cs o> THE CONTROL OF FLOODS BY RESERVOIRS. 161 ^ CO T-( T-H 1-1 C-l SOOO'^t-OsOt-OitiOiOcD !:OiCcOOO'^CTiQOCri0005tOCO rO'O'— 'cO'—'O'OOt^cO'— 'O^-- — -' lOt^CQCD'— 'CO'^C^^^OOOCOO-— '»0' •^ ^ CO CO CO -^ cfi c^^ •* CO "^ CO '* ■5 CD -^ CO 1— « -^ q -r 00 b-OiO ■1 CO O CO O O 29,672 29,672 29,754 29,672 29,672 29,672 29,754 29,672 29,672 29,672 29,754 29,672 29,672 29,672 29,754 29,672 29,672 29,672 29,754 29,672 22,193 t-QO 82,724 108,051 15,706 54,152 39,467 7,812 20,566 20,748 61,586 •-( o C^ O t- (M »0 lO iOOOOMOOOCOO COOCi"^'— 'OOCOfMCDcOt-^fMO'— <'rt-OOI>-000 rfODTt^'— (lO-^COCO-rf'— "Ce*— b-OOOOiOCMiOOOCO -coiococoibco^oc^c DO»OTt^CO'^r^cDOi'^00»0"^OcO>OTt*C ;ooa--ciO'rt" :,o--aicr^'— ■iooioOt-ic^c-" oo-*criOcoc5-*co _*l .^ r-M-_ .f-, OO -<^ CO _CO b- c» m" —i cm" ci c^i i-H T-T .-H (MiMcOfMCMC^cOC GOiOOC^O"— ''— 'O'— tiM»OOtOOOOtDcDOOOO CD CO -H "T^i :o O CO (M -— ' Ir^ O t^ <^C^ CO ;^aiOiO'MOOO(M'^l^"*iOOOCDOcDOOO lOO-^O-— '— cOOOiOiOi^ cD00iOI>-iOI>--^"r^t -cOiOCOCC»OC30iOC^(N-^ CO Oi lO OO O rt-Oft'-l(MCOiCCOOO (Mc^^o-*ooTfr--co-^ooocooo CO CO b- OO CO »0 T-H CO CO b- O^iO CD -rf -tl ■ CO* o cT ■^' »o ^ i>r tC co' ■^" t-^ iO" t^ to C5 CO " ■ " Ol r-i Oi 1-H 1— I T-1 CO '-H — 1 r- -^ CQ -^ CO 5 o c:> CO oD i-H ir^ J TJ* O "Tt* lO T-t CO JOOOOOOOOOOOOOOOOOOOO coS OOfM^OOt^WiO^^Os-^COb-OOCT-COiOO-O^Heo COCOtOcD*-«OCOOO'-<"r}HCSCOCO Tj<-Tt-i" t-Tio' ."<:J4iOt-*»0'^l^C0 t--(M'^co"rr cj«u'*T' li— tt-^c^ldCO lOOO'— tTfCO CicDO 3 arC5"c4"cD OO" Tfi"iO C^oT'-h' oo'Tjrco' 3CO'-*'-• oo o -gOi-'OOCi^t^C^ 5 CD O »0 -M^UOOO CO_ - O -f" t-^ — ' to ^ o D CD lO GO »0 C^) !M -# cDI--00050i-. 1 >. — 1 43 -O tJ 3 O. c ;^ D. c o 03 O O C a c8 ja £ &; rl ^ ^ o o •2. £ o d 3 o a "o 1 3 R o ^ o ^ F1 £ nJ= -rt ■^ d Oi OJ s >> n qa 'V ^ o 1 £ J o t3 J3 '^. ^ b: !- -d L- o ^ o o. o g E^ °:S a>-S oj 0) 3 o. S o o -^ o 111 g ^ iH 3 ^-^ m-O >, &ii*^ bo oj ja ^ 162 WATER RESOURCES OP CALIFORNIA. a; C Hi o > (0 n vc nt o z < Qi fa CO n b CQ < z < c/3 fa Q fa H <; z fa CO C o 3 O s CO O u CJ CO U 4-> fa o >> cs Ml 1 c & 3 'o z < in H fa O S 3 C/3 o o 4) (0 o o 3 U 4) (0 rf >. ^, CO Wi Z U CO CO CQ 3 < -tf* H (0 o •o I a 3 •a •a c o c 3 «t rt S o o "o a> vi CM c^ .S B continuous flow eriualized between seasons by over-year storage in acre-feet Flood control, seasonal and over-year storage coordinated if! "2 O Q. " q3 ^ a ^ ^ "=• ti to < Flood control, seasonal and over-year storage coordinated ill Flood control and seasonal storage coordinated III m Maximum flood control reserve or first 131,000 acre-feet of capacity ic "Si o'V 00 ^ J? n c o V V3 Flood control, seasonal and over-year storage coordinated O'-'S Flood control and seasonal storage coordinated i|-f 180,000 acre-fcct capacity Maximum flood control reserve or first 131,000 acre-feet of capacity Flood control water passing Azusa during flood season at rates less than 1,900 second-feet in acre-feet Flood control, seasonal and over-year storage coordinated 180,000 acre-feet capacity « p. 11 ^ o o o ^ o c o> o ps '1 o <" o b. 240,000 acre-feet capacity Ov- u Maximum flood control reserve or first 131.000 acre-feet of capacity ■ THE CONTROL OP FLOODS BY RESERVOIRS. 163 I(M-tOcOOcOOiOOO'*OiTt<':DCTi'#C^cOCO'^OOOcOrt*.^l>.__C3 (M^CO CO ^'^ ■^ CT) CO C^if5 00 05_ 1-H u5 -^'co'i-H crT CO eo' coo' t^'c3r^"«*^'ea u:ri-H b^ CO o^^ lO'-^Hi— i-«^C^C0C^C^C^'-H»O-^'^ '-tOOOOOW5OiCOOOC0OO^-rOc3ii-i0iO'"* CO OO lO Oi 00 *-• COM* Oi CD »-H OO ^^t-^^ l^Tj* CO Tt*_0^ •** CO 1-H OO -^ Tt< CO "3 "^ *-* Ci ^H .-« CO ^ c^^ •^c^' lo CO w'^o" CD GTc^'iOio Oi t^ci^oo coco .-» CO «-l WCOi-HC^ CO^-I cOOOOOOOOOOCOOOOOOOOcOOStJ^cOOOOCDOOOOOO 1-I.-H CO »0 OS CO »n OOOOOOOOOOOOOOCDOO-^O0iOOOOOC»5OOOO OOOOOOOOOO-*aic^CTiCiCiOioi05oia-..aioiOiaio:oicji050icnCT)Oitji 164 WATER RESOURCES OF CALIFORNIA. tt u b > 1— 1 a: o hi _) o u VI o in -0 o 09 < z z Q a: s 3 s (A ■4-) o u CO > C/3 Z o Q C8 c o -l-l u a Id Ml CJ CO oi ^<: •n hr n o^ •0 CO u > (3 O w Pu o CO ■M ^H a; o o U (0 C <4-l 1 c t w u U s z > H (4-1 (U -M <: <: w a (U CO >H >> •n 3 Wi H 3 "Soli's 3-S S 5 fr " •a c «. o o o •ill 11511 4 " " =^ rt^ _-r es S • ■= S — CJ — o o . - l£S is go a § M rt -J.S w « * gg •o2 o" i 9 2 S §■ ■50 c S^- ?> THE CONTROL OF FLOODS BY RESERVOIRS. 165 »00000000":)'«:t«0'*iOiCOOO^OiOOO OO CO O O CO '-H OS t— Oit^OOCOOi r^ ■^ C0OOOOOOO05Tt«(Ma5iO— t 00 00 »0 lO <:D Oi t^ r* coco C^l c^ OOOOOOOOOOC kCOiOCr^OOC^COMO^tiO'-HOOOOO^ OOOOt--O00O0i(MOO00t^OOOOM CO '~1 oo-^ *— t'^'- .-i CO 1-i CO 1-i c ■^ CO CO CO c^ t-- CO uO 1-^ C0OOO--^i0C<10SC0OO00 i— > ift (M fsi kmn c^ y-* <^> c^ C5 -^»-,,ooooooocoajc O C5 "OC^ CO i>.o Ca CO «0 O '^'^^ OOOOOOOO'^cOi-tOOO'-toOC^^'OOCOOOOiOOOOO CO Ol'^ t-H OOOOOOCqOO-^OOtOOOOOOO'-'COOOOOOlOOOOO'^ 'MOOOC^OOOOcnOOCS'-iiMOOO-^iOOOOO'-iOOOOOO'-* O lO ?0 1— I O lO lO CO C<) lO O "* -^ t-^ 1— < OS CO CO OO f^^CS ^C) OO CO "^ ^'"1.^ '^_ "-L *^ ^ CO "^ oo" o oToT t^^r^-^ oTos'i-T ■ co ■***" i>^ oo ^ CJ ^ T-i OS CS ■^ CO O t^ CJ CO '^ ooooooc^ooco ^ _iOOCOOOOOCHMiOOOO^Oii3000t^ t^ CD >— « OO 1-H OS OS 00 CO lO t* CO *0 lO escort* CO OS "^ ty'3 « o gg C CD O « ll. ill ill Maximum flood control reserve or first 131,000 acre-feet of capacity Flood control water passing Azusa during flood season at rates less than 1,900 second-feet in acre-feet Flood control, seasonal and over-year storage coordinated 180,000 acre-feet capacity Flood control and seasonal storage coordinated ^83 Maximum flood control reserve or first 131,000 acre-feet of capacity k 1 THE CONTROL OF FLOODS BY RESERVOIRS. 167 Tt*000000000'*'«*-C^O(MOOOOOOOOOO OiOOO ooo CO 00 (M Cft O CO I to (M CO OOOOOOOOOCO-^OOOOOOOOOOOOOOOOOOO OOOOOOOOOt^OOOOOOOOC -OOOOO'-HOOOO 000000000-^COOOOiftOOOOOOOOOO»00000 000 00 000 0(Mt^OOOOOOOOOO»000000000 OOOOOOOOOOO'^OOiO'-iOOCOC^OOOOOOr-COCOOOO Ci cDaD00O«D t^OO -rV OOiOO OOOOOOOOOOOOOO -.0 00 00000 0^0000 OOOOOOOOOOOOcOiOOiOO^OOOOOOOOOOOOO COOOO'^OOOOOOOOOOiMiOOOOO-^OCOOOOOOO^OOOO CO -^ !r> Oi ic:d CO -^ (M lO oi r^ ^ ^f o o 05 CO CO 00 cr- oo t-- i - o o c^ ¥ W00asOWMc0-rJ4»CcDI^00CT>O'-iCOOOOOOOOi' 00 00 CO Oi 05 c 1 > o" oc^oooooooooo OOOOasO^Oi-HOOOiOi0010SOSOiOi005030iCTSOS050dO;wi s Oi Ci d Oi Oi ^ 11— r.2411 170 WATER RESOURCES OF CALIFORNIA. 0^ u Hi > n 1— 1 u C u Hi en (0 u b u CO >— 1 Ui y U 1 C o N (X '0 CO hJ fTl !J u 2 C/J Ui < Q Q U CO 3 a o (/) <4-c O (X o U 4-1 4-> a s C/) 1 3 Wi tT u H u CO •0 § 1 o > u u < c Ix, 0^ 4-1 c n ^ CO m z u >^ 3 o 3 Yield in a uniformly continuous flow equalized between seasons by over-year storage in acre-feet Flood control, seasonal and over-year storage coordinated Ill III Aggregate of natural flow up to 152 second-feet passed for prior rights in acre-feet Flood control, seasonal and over-year storage coordinated ill ill ca c o i? " es •a = i-s o o o = £. ° S" ■n o o "> b. ill o' o ^ Maximum flood control reserve or first 131,000 acre-feet of capacity •a o Seasonally stored water in acre-feet Flood control, seasonal and over-year storage coordinated o tj >•■ 3 < « o Flood control and seasonal storage coordinated o 5 — o 55 Maximum flood control reserve or first 131,000 acre-feet of capacity Flood control water passing Azusa during flood season at rates less than 1,900 second-feet in acre-feet Flood control, seasonal and over-year storage coordinated O ^ '^ is: 1 OC0'*"*'<»i'*OO-*t^OOt^OOOO'J«OOO ■^ IM ■"^ •«*< -"J^ ■.*< Tj«O0 OO ■* OOOOOOOO— OOrt -HOOOO <— lOO — -HO0P50000O0O0 OOOOOOOOOOIMOOOIMOOIMO'^OOOOO'^OOOO OOOOOOOOOOC^IO — CO-^OOIMOOOOOOO-^OOOO « ooo o o OOOOOOOOO^iOOO'^OOOCl'^OOOOOO'-^OOOO 000000000000000000000000=00000 00 000000000000000000000000000000 000000000000000000000000000000 0000000 oocnooooooooooo 000000000 OOOOOOOOOOCiCOOi^HcoOOOSOSOO-^OOOOMOOO OOOOOOOOOOCOOOOOOOOCOOOOOOOOOOOOOC 50 1-1 CO -^ IM OOOOOOOOOOmOCDWSOOOOOOOOOOOOOOOO OOOOOOOOOOCiOOt^OOOt 2 Oi 05 O O O O O O ^ ^ Oi ^' O^ ^i 172 WATER RESOURCES OF CALIFORNIA. a: u u Wi > Si C _) u (0 Di tf) O < 7, PQ O 53 ■t-l < F M z < Oh CO Q 3 s Si o CO C/5 Q C8 r X CO l-l a X o 05 H S u CO c/5 < Z p— ( 4-> 3 O n 4) bD > 2 q 2 "0 •Si (A (A CO C CO (0 UJ Uh CO ^^ o N u 0^ U (0 i CO , 1 M c u u (/J Q «t O w a; pa < Z n 4-1 3 a ?1 CO o U 4-1 a s ^ ^? (U ■4-> & CO >> CO 1 C U ^ •n < £ o « 3 C 3 C O CO In Z U CO CO (A >^ 3 c o i a a 1 2 o "S s "1 in Yield in a uniformly continuous flow equalized between seasons by over-year storage in acre-feet Flood control, seasonal and over-year storage coordinated -3 § 1 *■'' 00 o^ — bO o.'C ^ 3 f « C3 on C » "o °- 2 1 S Flood control, seasonal and over-year storage coordinated til a ll 11 — o II o ill ill Maximum flood control reserve or first 131,000 acre-feet of capacity .5 11 3 o C3 C O 1 Flood control, seasonal and over-year storage coordinated Oo >. i'il ll 11 li o a o U. o"S >> o o S 5:|2 §-2-5 Maximum flood control reserve or first 131,000 acre-feet of capacity Flood control water passing Azusa during flood season at rates less than 1,900 second-feef in acre-feet Flood control, seasonal and over-year storage coordinated ll a o — o o o c » o « o « i;- o'i S ill Maximum flood control reserve or first 131,000 acre-feet of capacity 1 THE CONTROL OP FLOODS BY RESERVOIRS. 173 OOOOOOOOOO0t;OOCOOO-*OOOOOOOt*OOOO Oi 0! u ^ o b) (/I o ^ -0 o . 9 1 >> § ^ C9 Q 3 »- S o CO >1 C/3 Q C8 X V4 J5 o z o 05 § J2 & C/3 z l-H 3 o "^ o bfl o O o p u u U (0 CO es a CO u 2 u b CO ,-i w s O N o DC U 4) 1 CO C o (0 CO hJ HH Hi C 3 a i u (0 in »— I J « -^ •0 a a CO o: o t u < C « — (0 3 C ^ 3 o 3 +j lu >> 0\ +j c O ^' « o ;ri (0 U >H 3 ^ N '■' V) o Yield in a uniformly continuous How equalized between seasons by over-year storage in acre-feet Flood control, seasonal and over-year storage coordinated 180,000 acre-feet capacity a 8 ■3,0 « 'a m "^ C3 1 Flood control, seasonal and over-year storage coordinated » >» es c Si "> es "OS ^■S as — 2g c a> Si- °I " iL 240,000 acre-feet capacity 180,000 acre-feet capacity Maximum flood control reserve or first 131.000 acre-feet of capacity Seasonally stored water in acre-feet Flood control, seasonal and over-year storage coordinated Flood control and seasonal storage coordinated Oo >» Maximum flood control reserve or first 131,000 acre-feet of capacity Flood control water passing Azusa durine flood season at rates less than 1,900 second-feet in acre-feet Flood control, seasonal and over-year storage coordinated es is ig 11 11 sg 1» ill 180,000 acre-feet capacity Maximum flood control reserve or first 131,000 acre-feet of capacity a THE CONTROL OF FLOODS BY RESERVOIRS. 175 Tt.c^oooO'»'^oooo O O —* =)00000300000000000000000 oc::3;oc:c;c;c;oioooc;c:c;oc:ooooooooooooo oooooooor .-'^b-.irsccmcr. oocooooooococqoooo ■ ■ Ci t* *-i OO 05 CO tOOO CI '-« - C;OOOOOOOOONOOOOOO'*OCOOOOOOOOOOO SOOOOOOOO-^OOO-HOOOOOOSO-^OOOOb-C^OOOO CO Ci t~^ Oa CO CO OO OOO COO iOOOOC^OcOOCOCOCOt^Tj«»OWOO"5000000iOOOOOO C» '^ >0 lO lO — ' t-, 00 31 O — iM ro ' i.*^ -^ t— oc r; o -^ cq CO -^ I >dOOOOOOO<300- - 00 dO-^CQ CO-* W3 CO to 0000Q03iC;Ci0iC:C"-C131dC-31ClCiC53iC7;OSCS0;as0iCSCS0SO0i01 176 WATER RESOURCES OF CALIFORNIA. a CQ •s -o U4 z CQ u (0 ■4-> < H bD . z J & Q 3 s o Si, C/5 Q C8 X W< CO z o a; H § CO z 3 73 bO o > 2 o •0 U CO (0 Ih CO 4J Q, (0 u b o CO OS O N u a; U (0 C n 13 CO u u C ! 3 u tT C8 s T3 C o ^ 2 V < 3 C/3 w ..4 * 3 C ^ o o 3 ■M Uh >, CT^ 4J c o CO o u z u CO CO >^ 3 O c o o g 3 s es c _c < 1 2 o o e CO o Yield in a uniformly continuous flow equalized between seasons by over-year storaRC in acre-feet Flood control, seasonal and over-year storage coordinated 180,000 acre-feel capacity -i 3 I. O $ 1 1 Flood control, seasonal and over-year storage coordinated 0-0 § h 11 o o 1- Sit O-v ill Maximum flood control reserve or first 131,000 acre-feet of capacity Seasonally stored water in acrc-fcet Flood control, seasonal and over-year storage coordinated 0" i a 00 c 0. = a S ■5 ll 11 e ll. Oo >• '^ a 'J ••Maximum flood control reserve or first 131,000 acrc-fcet of capacity Flood control water passing Azusa during flood season at rates less than 1,900 sccond-fcct in acre-feet Flood control, seasonal and over-year storage coordinated £ — ll eg ll 1- c: If! =^ a 3 ill flood control reserve or first 131,000 acre-feet of capacity THE CONTROL OF FLOODS BY RESERVOIRS. 177 UD lO^ 10*10" lo uiTio io"io"io'»o io"io"if:rio io"io"io"w^irr C*^ COC<) CoO'^i— 'co^o<^^o^r^^ )0'-''^coccr~-oot--ooo • — i«)OOOOiOO"^C=>t-«.-«COCOiOiOiOCO-^t--00'— lOOOi'-T-fM )iOC^COcO00iOt»iOt>-^^t -t"CDiOC0iOiO00»0«C^'* COt^COOOOt^Ot*cDQO"^'-HQO«OC«cOeC!|>.C^O'-H-^COff»D(--COt^OOO iO,-(,-4»-.ioC^*OC^cOC300iCt^iOt^rt<-^ <^ »i3,-H,— I.— ikOC^iOC<»COcDOOiOt-lOt---^-^t-I>-I>-cOiOCOcCi>OOO^C^C^'^ CO tr^co coocD t O 00 CO ' ' -.-ot^ccoO'^'— 'oocoiMtTJcot— CQO'— '"^cocor-oor^ — .-.- .HCOOOOO'OO'^O'-'i— >cDOOiO»OiOeC''^t--00»-'0005'— I 0_0 Tf ^"^00 O '-'_»0 ■^.00_'^'-H_iO_"^C0^C0 ■^■-^^OO i-^b-^OO^tO o »o C^iO ■ _ _. _ ^ ^ j(_j (^ ^ jj^ OP y-, (^ j^ ^ 5,— ,^HT-iiOC^iOC^OcDOOiOI>*iOI>-Tp-^t-t c^ oco ■^ ^ coco 0--'COOOOOOOOCiCO»-i'r}OC^OC0C0t--CiOr-»0-HOOiO0000OaiC0C0rJv'^ '^'^ fo-^'tCiocCo-^'ioarcri^r^ocD f-roo c^Tco i-Tio •^ lO O CO 00 '— ' CTi '-'400(Mt^ iO<-t'*^H 00 — -^ CS OC5COi^CniOi-'CO , _ __ _ •^■^COCiCO'— "-^ C^Ci O O 06 CD Ci'iM »0 lO 31 -^ ^-^^irf ^ " *" * 00C<)OOI>-l^t^C^W01M^-0Ct-^0^i.0-H ooco 1— tco-^oooor-cococo-— 'cr, cooo ■^t^ t-*Tj.'«(t*cDOr-"*'^'— ■0000000 t'-'^riOOC-lcDOOOJ-rt'OO'^-^OOcD'—'CDOOO uo CO CO »0 CO c 1-1 O) (M .-( 10 t 1 00 i— ' CO Ol OOOOOOOOOO'MOOOt-OO'-tO'^OOOOOOOOOOO 000000000'*'MOCO(MC;OOt-.0'**0000»000000 00 »-ieqco eoOOO-^OiOOCOcOCJCOCONOiOOt^OOC^t^^^OOI^r^jCviOOO 1-1 Oi -rt* C5 O t— >0 ■^ r* CO t^ C^ ^ CO -^ OOOrt* Oi CO o oieoi-«t-c^c^co ^°^'~1,*^ ^ ^^"R. ^ c^ CO crT'^o^ci'w'co'Qo -^"loc^for*-*" OOrfTcO CO OJ OJ C^ CO !■» — < 10 •-< lO •-< CO 01 »-H t^OOCiO — C'lCO^»OCO^-OCav O'-.C-lCO'^iOCDb-OOCiO'-iC'lCO'^iAcO CS05C5OOOOOOOOOO — ^^ — «^^i-<-^— '!MC^c;c:~-.:7sc;3". dc~-CiC"-dC5C^ciCJCiaicrscr>cr>osci _2 ■Sj S t- t- ^ OJ9.3 en 53 CJ •- o ai p. 2 0-- 2" f*. ^-3 "^ - o»'£.2 5-2 OM a_S a.s|gaa>i"j-s.s -2.S o S I g g "c s- i^^ rt to to tb a « D rt 0-H taoS M.2 M^ g<- M s « > a 1 •- o nja »^ j3 ■" js cj J "2 Tj<_ -^^ 3 O 178 WATER RESOURCES OF CALIFORNIA. 0!> U I— I 05 CQ < O z < z o o > u cn (d Di CQ These figures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the exact period of analysis. In the computations from which this table is prepared, the water in storage on October 1, 1926, the end of the period, is less by this amount than on January 1, 1897, the beginning of the period. Since in the computations this water was released as flood control water during the first flood season of the period, the exact yield of flood control water for the period is less than hereshown by this amount. THE CONTROL OF FLOODS BY RESERVOIRS. 181 VOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE. Carried out on a Daily Basis. mary, see Table 1 5a, page 404.) Maximum controlled flow at Azusa 1900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year- Flood control, holding maximum reservoir space required (131,000 ac.-ft.) In reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 sec.-ft. maintained, other drafts only as required by reservoir operating diagram Flood control water Constant Year Stage of reservoir at beginning of year in acre-feet Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 49,122 52,963 33,933 13,032 2,006 -1897 43,458 15,687 13,032 1,688 1898 28,738 10,463 13,032 1,263 1899 14,443 11,976 13,032 644 1900 10,777 50,570 13,032 1,854 1901 34,881 21,816 13,032 1,463 1902 20,884 50,037 11,429 13,032 4,588 2,186 1903 46,597 24,180 13,068 1,836 1904 34,349 62,587 73,010 13,032 1,734 2,140 1905 46,561 67,456 136,655 13,032 19,376 2,350 1906 49,122 82,808 228,430 13,032 21,229 2,352 1907 46,591 56,444 10,356 13,068 1,928 1908 37,745 72,101 91,415 13,032 2,644 2,165 1909 55,928 54,518 68.002 13,032 1,911 1910 36,915 70,413 176,382 13,032 4,617 ?,194 1911 46,557 47,362 13,060 13,068 2,082 1912 44,605 40,386 2,687 13,032 1,909 1913 36,914 72,456 197,801 13,032 4,554 2,176 1914 46,605 73,157 35,855 13,032 7,618 2,201 1915 46,542 77,852 198,835 13,068 2,028 1916 48,979 60,160 8,027 13,032 1,946 1917 38,524 58,741 60,968 13,032 2,000 1918 40,923 37,874 13,032 1,623 1919 26,399 60,683 20,118 13,068 2,068 1920 44,192 54,013 46,315 13,032 352 2,108 1921 115,102 87,587 259,909 13,032 19,973 2,328 1922 48,963 51,298 13,032 1,850 1923 34,533 25,517 13,068 1,453 1924 20,428 21.878 13.032 1,010 1925 7.908 40,320 11,836 9,747 1,088 1,772 "1926 1,513.303 1,685,053 387,891 ^87,773 56,534 Total 50,867 56,641 13,039 '■2,950 1,900 Average <: In the computations for this table, the period of analysis closed with 1423 acre-feet more water in storage than at the beginning, the equivalent of 48 acre-feet per season. Since in the computations this water was stored in the last year of the period of analysis, the exact yield in seasonally stored water for the period is larger than here shown by this amount. 182 WATER RESOURCES OF CALIFORNIA. TABLE 16. SAN GABRIEL RESER COMPARISON OF WATER YIELD FOR THE USE OF Yearly Summary of Computations (For corresponding monthly sum Natural flow up to 152 second- Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Flood control alone Flood control partially coordinated Water drawn from reservoir only as required by Constant draft of 22 sec.-ft. maintained. reservoir operating diagram required by reservoir Flood Flood Run-off at control water control water Constant draft Year Azuaa Stage of Passed passing Azusa during flood Evapora- Stage of Passed passing Azusa daring flood from in reservoir by dam tion Waste reservoir by dam over- acre-feet at for from over at for year beginning prior reservoir spillway beginning prior storage of year in acre-feet rights in acre-feet season at rates less than 1,900 second- feet in acre-feet surface in acre-feet in acre-feet of year in acre-feet rights in acre-feet season at rat«3 less than 1,900 second- feet in acre-feet (22 second- feet) in acre-feet 1897 96,270 62,650 52,963 30,209 2,830 62.650 52,963 16 407 15,922 1898 15,687 72,918 15,687 13,484 2,273 70,937 15,687 10,849 15,922 1899 10,463 57,161 10,463 2,219 42,090 10.463 15.922 1900 21.986 54,942 11,976 2,166 24,561 11,976 15,922 1901 89,560 62,786 50.570 36,470 2,405 17,571 50,570 15,922 1902 22,314 62,901 21,816 2,357 38,663 21,816 15,922 1903 106,985 01,042 50,037 18,087 3,100 21,716 50.037 15.922 1904 26,836 96,803 24,180 3,157 60.266 24.180 15.965 1905 164,715 96,302 62,587 99,337 3,569 44.803 62.587 32,989 15,922 1906 241,430 95,524 67,456 201,800 4,497 94.565 67,456 184.996 15,922 1907 345,320 03,201 82,808 212,060 4,663 7,426 63.201 82,808 201.165 15,922 1908 72,950 101,564 56,444 62.322 2,245 100,648 66.444 59,629 15,965 1909 199,540 53,503 72,101 104,979 3,124 39.648 72,101 75,341 15,922 1910 118,450 72,839 54,518 85,557 2,072 72.839 54,518 83.808 16,922 1911 276,280 49,142 70,413 153,559 3,871 35.149 70,413 124,229 15,922 1912 73,620 97,579 47.362 11,255 3.573 97,099 47.362 496 16,965 1913 50,323 109,009 40.386 47,834 2.546 103,463 40.386 39.503 15,922 1914 299,710 68,566 72,456 227,682 3,549 55,522 72,456 198.812 15,922 1916 131,800 64,589 73,157 31,417 2,967 64,589 73,157 29.236 15,922 1916 294,220 88,848 77.852 238,753 3,262 75.288 77,852 209.378 15,965 1917 72,710 63,201 60,160 14.791 2.302 63.201 60.160 13.501 15,922 1918 137,140 58,658 58,741 61.007 3,629 44.206 58.741 31.054 15,922 1919 38,005 72,521 37,874 7,081 2,568 72.261 37,874 15.922 1920 113,730 63,003 60,683 41,059 3,263 54,111 60,683 16,619 15.965 1921 186,760 71,728 64,013 02,355 2,484 71,466 54.013 60,199 15,922 1922 316,690 139,636 87,687 301,585 3,953 125,786 87.587 271.925 15,922 1923 51,750 63.201 51,298 13,408 2,048 63,201 51,298 12.056 15,922 1924 25,933 48,197 25,517 2,012 33,817 25,517 15.965 1925 23,400 46.601 21,878 1,984 16.888 21,878 16.922 •1926 107,400 46,139 40.320 2,842 1,744 40,320 11.909 Total 3,731,977 1,513,303 ''2,078,091 87,430 7,426 1,513,303 •1,672,152 473.905 Average 125,445 50,867 ^69,785 2,939 250 50,867 ■^56,207 15.930 "Partial year, January 1 to October 1. ''In the computations for this table, the i>eriod of analysis closed with 47,727 acre-feet more water in storage than at the beginning, the equivalent of 1604 acro-fcct per season. Since in the computations this water was stored in the last year of the period of analysis, the exact yield of flood control water for the period is greater than here shown by this amount. THE CONTROL OF FLOODS BY RESERVOIRS. 183 VOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING RESERVOIR SPACE. Carried out on a Daily Basis. mary, see Table 16a, page 426.) feet passed for prior rights. Maximum controlled flow at Azusa 1900 second-feet. Maximum flood control reserve 131,000 acre-feet. with conservation other drafts only as operating diagram Fiood controi completely coordinated with conservation Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 sec.-ft. maintained, other drafts only as required by reservoir operating diagram Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of year in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over- year storage (22 second- feet) in acre-feet Variable summer draft from seasonal storage in acre-feot Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year 2,691 2,076 1,607 1.078 1,976 1,523 2,476 2,154 3,455 4,420 4,627 2,012 2,985 1,892 3,766 3,433 2,393 3,453 2,786 3,112 2,122 3,368 2,359 3,108 2,306 3,841 1,858 1,380 744 1,866 0. 3,351 62,650 54,261 36,413 19,043 12,335 33,557 16,759 51,257 36,026 51,265 58,963 51,278 39,648 64,193 35,149 51,321 51,497 43,413 51,337 51,328 60,164 44,206 51.331 33,692 51,342 125,786 63.201 33,817 16,888 1,744 52,963 15,687 10,463 11,976 50,570 21,816 50,037 24,180 62,587 67,456 82,808 56,444 72,101 54,518 70,413 47,.362 40,386 72,456 73,157 77,852 60,160 58,741 37,874 60,683 54,013 87,587 51,298 25,617 21,878 40,320 16,407 13,658 39,397 127,639 10,159 52,260 75,1P2 100,816 145,722 15,984 152,317 10,464 3,595 39,506 195,520 12,056 15,922 15,922 15,922 15,922 15,922 15,922 15,922 15,965 15,922 15,922 15,922 15,965 15,922 15,922 15,922 15,965 15,922 15,922 15,922 15,965 15,922 15,922 15,922 15,965 15,922 15,922 15,922 15,965 15,922 11,909 16.901 4,235 54,528 107,768 123,335 32,119 70,041 7,761 54,901 24,232 36,625 49,016 16,978 606 77,276 2,466 1,926 1,448 796 1,846 1,374 2,293 1,922 2,781 3,189 3,301 2,012 2,593 1,892 2,916 2,356 2,099 2,785 2,514 2,625 2,122 2,741 1,848 2,454 2,269 2,970 1,858 1,380 744 1,866 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 "1926 76,867 2,584 3,351 113 1,513,303 50,867 =1,010,662 '^33,972 473,905 15,930 676,322 22,734 65,386 2,198 Total Average " These figures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the exact period of analysis. In the computations from which this table is prepared, the water in storage on October 1, 1926, the end of the period, is less by this amount than on January 1, 1897, the beginning of the period. Since in the computations this water was released as flood control water during the first flood season of the period, the exact yield of flood control water for the period is less than here shown by this amount. 184 WATER RESOURCES OF CALIFORNIA. TABLE 17. SAN GABRIEL RESER COMPARISON OF WATER YIELD FOR OPERATING FOR FLOOD CONTROL Yearly Summary of Computations (For corresponding monthly sum Natural flow up to 152 second- Maximum controlled flow at Azusa 1900 second-feet. Height of dam 383 feet Capacity of reservoi 180,000 ac.-ft. Constant draft of 22 sec.-ft. maintained, other drafts only as Run-off required by reservoir operating diagr UD at Flood control Year Azusa Stage of reservoir at beginning of year in acre-feet water passing Constant draft in Passed by Azusa during from over- Evaporation Waste over spillway in acre-feet acre-feet dam for flood season at year storage from reservoir prior rights rates less than (22 second- surface in acre-feet 1,900 second- feet) in in acre-feet feet in acre-feet acre-feet 1897 96.270 62.650 52,963 16,407 15,922 2,691 U 1898 15,687 70,937 15,687 10,849 15,922 2,076 1899 10,463 42,090 10,463 15,922 1,607 U 1900 21,986 24,561 11,976 15,922 1,078 1901 89,560 17,571 50,570 15.922 1,976 1902 22,314 38,663 21,816 15,922 1,523 1903 106,985 21,716 50,037 15,922 2,476 1904 26,836 60.266 24,180 15.965 2,154 190.5 164,715 44,803 62,587 32,989 15,922 3,455 1906 241.430 94,565 67,456 184,996 15.922 .4,420 1907 345,320 63,201 82,808 201,165 15,922 4,627 3,351 1908 72,950 100,648 56.444 59,529 15,965 2,012 1909 199,540 39,648 72,101 75,341 15,922 2,985 1910 118,450 72,839 54,518 83,808 15,922 1,892 1911 276.280 35.149 70,413 124,229 15,922 3,766 1912 73.620 97,099 47,362 496 15,965 3,433 1913 50,323 103,463 40,386 39,563 15,922 2,393 1914 299,710 55.522 72,456 198,812 15,922 3,453 1915 131,800 64.589 73,157 29,236 15,922 2,786 1916 294,220 75.288 77,852 209,378 15,965 3,112 1917 72,710 63,201 60,160 13,501 15,922 2,122 U 1918 137,140 44,206 58,741 31,054 15.922 3,368 1919 38,005 72,261 37,874 l.i.922 2,359 1920 113,730 54,111 60,683 16,619 1.5,965 3,108 1921 186,760 71,466 54,013 60,199 ] 5,922 2,306 1922 316,690 125,786 87,587 271,925 15.922 3.841 1923 51.750 63,201 51,298 12,056 15,922 1,858 1924 25,933 33,817 25,517 15.965 1,380 1925 23,400 16,888 21,878 15,922 744 •1920 10/ ,400 1,744 40,320 11,909 1,866 Total 3.731,977 1,513,303 bl,672,152 473.905 76.867 3,351 Average 125,445 50,867 ''56,207 15,930 2,581 113 » Partial year, January 1 to October 1. •> These figures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the ejtact period of analysis. In the computations from which this table is prepared, the water in storage on October 1, 1926, the end of the period, is less by this amount than on January 1, 1897, the beginning of the period. Since in the computations this water was released as flood control water during the first flood season of the period, the exact yield of flood control water for the period is less than here shown ty this amount. fHE CONTROL OP FLOODS BY RESERVOIRS. 185 VOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR AND CONSTANT DRAFT ONLY. Carried out on a Daily Basis. mary, see Table 17a, page 448.) feet passed for prior rights. Maximum .flood control reserve 131,000 acre-feet. Height of dam 425 feet Capacity of reservoir 240,000 ac.-ft. Constant draft of 41 sec.-ft. maintained, other drafts only as reqoired by reservoir operating diagram Flood control Stage of reservoir at beginning of year in acre-feet Passed by water passing Azusa during Constant draft Evaporation U^TnQfp fivpr Year dam for prior rights flood season at rates less than (41 second- feet) in from reservoir surface 11 doLC UVCl spillway in in acre-feet 1,900 second- feet in acre-feet in acre-feet acre-feet 122,650 52,963 15,089 29,672 3,802 1897 117,394 15,687 29,672 3,170 1898 84,552 10,463 29,672 2,461 1899 52,419 11,976 29,672 1,677 1900 31,080 50,570 29,672 2,116 1901 38,282 21,816 29,672 1,269 1902 7,839 50,037 29,672 1,959 1903 33,156 24,180 29,754 1,168 1904 4,890 62,587 29,672 2,931 1905 74,415 67,456 90,216 29,672 5,300 1906 123,201 82.808 190,451 29,672 5,733 1907 159,857 56,444 57,178 29,754 3,216 1908 86,215 72,101 47,055 29,672 4,088 1909 132,839 54,518 82,307 29,672 3,114 1910 81,678 70,413 96,025 29,672 4,819 1911 157,029 47,362 29,754 4,471 1912 149,062 40,386 24,723 29,672 3,529 1913 101,075 72,456 169,521 29,672 4,543 1914 124.593 73,157 27,425 29,672 3,903 1915 122,236 77,852 181,433 29,754 4,216 1916 123,201 60,160 12,270 29,672 3,308 1917 90,501 58,741 2,982 29,672 4,212 1918 132,034 37,874 29,672 3.481 1919 99,012 60,683 29,754 3,860 1920 118,445 54,013 35,443 29,672 3.457 1921 182,620 87,587 253,954 29,672 4,896 9122 123,201 51,298 10,928 29,672 3,084 1923 79,969 25.517 29,754 2,376 1924 48,255 21,878 29.672 1,601 1925 18,504 40.320 22,193 2,054 »1926 1,513,303 1,297,000 '883,173 99,814 Total 50,867 =43,597 "29,686 3,355 Average ° These figures contain 61,313 acre-feet total or an average of 2060 acre-feet per season of water contributed from outside the exact period of analysis. In the computations from which this table is prepared the water in storage on October 1, 1926, the end of the period, is less by this amount than on January 1, 1897, the beginning of the period A supplementary analysis, having the same amount of water in storage at the beginning and at the end of the period, was made to obtain the exact yield for the period. This gave 47,900 and 23,300 acre-feet per season, respectively, for the flood control wate rand uniformly con- tinuous flow instead of 43,597 and 29,686 acre-feet, respectively, that are shown herein. 12—52411 186 WATER RESOURCES OF CALIFORNIA. TABLE 18. SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir, Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa in second-feet 0-250 Year Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially coordinated with conservation Constant draft of 22 seoond-feet maintained, other drafts only as required by reservoir operating diagram Flood control completely coordinated with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 •1926 4,122 191 889 1,808 513 591 4,590 62 1,409 445 1,342 161 477 597 14 793 209 137 2,341 307 984 1,966 107 401 688 2,251 23 88 310 261 143 12 151 324 78 1,375 225 610 I) 15,049 15,747 15,922 15,922 15,922 15,922 15,922 15,965 15,137 13,391 10,950 15,179 14,003 14,307 14,046 15,921 15,311 12,694 15,182 12,563 15,398 14,831 15,922 15,485 15,092 11,342 15,224 15,965 15,922 11,909 1,966 u U u 1,103 148 310 79 156 199 134 558 16 298 610 16,901 4,235 20,865 U 21,613 7,761 15,509 19,211 29,799 26,724 16,978 606 15,049 15,922 15,922 15,922 15,922 15,922 15,922 15,965 10,469 7,635 5,280 15,484 12.127 14,397 6,413 15,965 15,922 7,676 13.960 12,564 15,006 12,040 15,922 15,965 15,398 5,104 l.'),224 15,965 15.922 11,909 Total Average 21,982 739 9,013 303 442,145 14,862 5,577 188 180,202 6,057 402.893 13.543 • Partial year. January 1 to October 1. THE CONTROL OF FLOODS BY RESERVOIRS. 187 TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir, Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa in second-feet 250-500 Flood control completely coordinated Flood control alone Water drawn from reservoir only Flood control partially coordinated with conservation Constant draft of 22 second-feet with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet as required by reservoir maintained, other drafts only through critical period; constant draft of 22 second-feet maintained , operating diagram as required by reservoir operating diagram other drafts only as required by reservoir operating diagram Year Flood Flood Flood control control control water Seasonally water Seasonally water Seasonally passing Azusa during flood stored water Constant passing Azusa during flood stored water Constant passing Azusa during flood stored water Constant released flow from released flow from released flow from as a over-year as a over-year as a over-year season at rates less than 1,900 second- variable summer flow in acre-feet storage in acre-feet season at rates less than 1,900 second- variable summer flow in acre-feet storage in acre-feet season at rates less than 1,900 second- variable summer flow in acre-feet storage in acre-feet feet in feet in feet in acre-feet acre-feet acre-feet 1897 12,490 10.201 785 10,201 785 1898 1899 1900 1901 8,976 1902 1903 1904 U 1905 952 1,699 U 174 33,564 5,235 1906 2,815 U 2,679 174 91,153 0,804 1907 10,817 (1 7,^72 1,090 2,696 49,281 4,100 1908 566 44 1,286 262 t_ 1909 2,624 4,553 524 4,553 10,506 3,011 t 1910 3,861 3,468 393 3,468 393 f 1911 1,156 634 87 634 70,041 8,070 1912 353 44 1913 1.191 131 1914 4,524 5,633 480 1,994 39,392 6,195 1915 2,581 2,186 218 2,170 5,021 1,570 1916 3,074 2,304 174 468 6,825 1,484 1917 8,843 8,589 262 7,658 785 1918 2,197 2,149 175 22,293 3.795 1919 1,686 1920 11,700 3,424 218 1921 352 44 1922 2,899 2,714 218 955 77,275 8,071 1923 4,220 3,871 349 3,871 349 1924 1925 M926 Total 85,315 64,338 5,584 39,954 405,451 50,909 Average 2,868 1 2,162 188 1,343 13,629 1,711 ' Partial year. January 1 to October 1. 188 WATER RESOURCES OF CALIFORNIA. TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir, Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa in second-feet 500-750 Year Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially coordinated with conservation Constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control completely coordinated with conservation Reser\-oir emptied each summer to a level that would maintain a constant draft of 22 second-feet through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 •1926 3.366 11,032 2,133 3,195 14,447 3,735 2,833 5,594 823 4.809 1,816 15,131 5,155 13,094 5,358 8,181 878 5,753 6,225 990 1,316 1,345 3,177 13,749 0,253 2,705 5.907 5,780 2,200 14,527 4,912 11,619 3,402 8,547 5,683 44 44 U 44 131 654 305 131 305 262 87 611 262 480 131 392 305 990 8,960 1,064 2.988 2,705 4,161 3,673 1,682 2,248 1,107 5,696 5,683 14.756 74.054 44 (1 U 960 4,624 44 175 131 218 174 87 131 44 262 305 Total Average 113.618 3.810 92,112 3,096 4,188 Ul 40,957 1.377 88.810 2,985 7,199 242 • Partial year, January 1 to October 1. THE CONTROL OF FLOODS BY RESERVOIRS. 189 TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir, Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flew at Azusa in second-feet 750-1,000 Flood control completely coordinated Flood control alone Water drawn from reservoir only Flood control partially coordinated with conservation Constant draft of 22 second-feet with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet as required by reservoir maintained, other drafts only through critical period; constant operating diagram as required byreservoir draft of 22 second-feet maintained, operating diagram other drafts only as required by reservoir operating diagram Year Flood Flood Flood control control control water Seasonally water Seasonally water Seasonally passing Aziisa stored water Constant passing Azusa during flood stored water Constant passing Azusa during flood stored water Constant during flood released flow from released flow from released flow from as a over-year as a over-year as a over-year season at rates less than 1,900 second- variable Slimmer flow in acre-feet storage in acre-feet season at rates less than 1,900 second- variable Slimmer flow in acre-feet storage in acre-feet season at rates less than 1,900 second- variable summer flow in acre-feet storage in acre-feet feet in feet in feet in acre-feet acre-feet acre-feet 1897 1,783 1898 1899 1900 1901 5,590 c 1902 1903 c 1904 1905 3,360 10 971 3 305 1,520 44 1906 3,183 4,145 131 1907 17,511 ices'? 524 13,220 393 1908 2,800 87 1909 11,714 10,091 305 1,427 44 1910 4,034 3,903 131 5,393 174 1911 1,563 1912 1913 1,501 1914 2,504 87 3,740 131 1915 0,824 c,204 174 5,204 174 1916 16,279 9,467 305 1917 1918 16,235 7,715 218 1919 1920 9,715 1,546 14 1921 1,436 1,215 44 1922 24,377 24,627 742 3.919 131 1923 ■ 1924 1925 "1926 Total 125,105 98,221 3,010 37,223 1.178 Average 4,205 3,302 (» 101 1,251 40 • Partial year, January 1 to October 1. 190 WATER RESOURCES OF CALIFORNIA. TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE. Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir. Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa in second-feet 1.000-1,250 1 Flood control completely coordinated Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially coordinated with conservation Constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Year Flood Flood Flood control control control water Seasonally water Seasonally water Seasonally passing Aiusa during flood stored water Constant passing Azusa during flood stored water Constant passing Azusa during flood stored water Constant released flow from released flow from released flow from as a over-year as a over-year as a over-year season at rates less than 1,900 second- variable storage in season at rates less than 1,900 second- variable storage in season at rates less than 1,900 secopd- variable storage in summer flow in acre-feet acre-feet summer flow in acre-feet acre-feet summer flow in acre-feet acre-feet feet in feet in feetin acre-feet acre-feet acre-feet 1897 2,181 1898 2,199 2,136 44 1899 1900 1901 1902 1903 1904 1905 8,014 1.923 44 1.850 44 1906 2,182 2,238 44 1907 42,477 41,522 916 25,319 523 1908 2,136 44 1909 9,501 9,302 218 1.679 44 1910 1,802 1,758 44 1,741 44 1911 6,102 2,013 44 2,013 44 1912 1913 1914 5,845 131 1,909 44 1915 2.059 2,014 43 3,959 87 1916 6,170 4,061 87 1917 1918 11,795 9,493 218 3,594 87 1919 1920 2,182 1921 1922 20,396 u 17.755 392 1923 1,979 1,892 44 1.892 44 1924 u u 1925 U u •1926 u U u ToUl 119.039 101.952 2,269 46,092 1.005 Average 4,001 3,427 76 1,549 34 ■ Partial year, January 1 to October 1. THE CONTROL OF FLOODS BY RESERVOIRS. 191 TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE. Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir. Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa In second-feet 1,250-1,500 Year Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially coordinated with conservation Constant draft of 22 second-feet maintained, other drafts only as req Jired by reservoir operating diagram Flood control completely coordinated with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre-feet Constant flow from over-year storage in acre-feet 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 n926 2,255 46,603 2,576 2,404 2,435 2,284 8,806 14,287 (J 2,957 43,615 2,391 4,890 2,334 11,906 44 785 44 87 44 218 12,354 2,157 4,861 218 44 87 Total Average 81.650 2,745 68,093 2,289 1,222 41 19,372 651 349 12 • Partial year, January 1 to October 1. 192 WATER RESOURCES OP CALIFORNIA. TABLE 18 (Continued). SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. AVERAGE SIZE OF FLOWS OF WATER YIELD FOR THREE STEPS IN COORDINATING THE USE OF RESERVOIR SPACE. Height of dam, 383 feet. Maximum controlled flow at Azusa, 1,900 second-feet. Capacity of reservoir, Maximum flood control 180,000 acre-feet. reserve, 131,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Size of total flow at Azusa in second-feet 1,500-1,900 Year Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially coordinated with conservation Constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control completely coordi nated with conservation Reservoir emptied each summer to a level that would maintain a constant draft of 22 second-feet through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control water passing Azusa during flood season at rates less than 1.900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre feet Constant flow from over year storage in !\cre feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water released as a variable summer flow in acre feet Constant flow from overyear storage in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water 1 eleased as a i'ariable summer flow in acre feet Constant flow from over year storage in acre-feet 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 •1926 6.267 11.094 9.983 14.024 84.365 189,834 83.041 59,684 73,592 70,147 137,802 11,094 45,510 215,528 17,540 189,279 17.477 6.940 60.041 233,566 u 3,250 7,290 16.650 169.112 78.774 58.940 45.054 69.273 115.414 38.360 174,009 17,308 1/6,686 6,872 58,632 206,151 U u 44 87 218 2,007 1,003 742 567 872 1,440 480 2,181 218 2,181 87 742 2,618 3,250 10,287 23,964 63,987 2,725 41,613 61,545 93,929 132,093 2,770 151,716 38,383 179,792 l/,292 u 44 130 523 784 44 521 783 1,177 1,658 44 1,917 480 2,267 Total Average 1.536,808 51,658 1.241,774 41,741 15,487 521 806,054 27,095 17,292 581 10,372 348 • Partial year, January 1 to October 1. I 194 WATER RESOURCES OF CALIFORNIA. Oi OH •J O O > w to "^ o^- tj; p a, o CO t^ cc o u^ ^ ^ ,-4 C5_Ci CTC5 <'oca2>S' H fe to c3-^ g*"*.^ So~ « t; H ° 2. 01 "^ P 2 S'o ^ « Q ■- ■* »1 rt t?< o fe rt— ;.S S " S o S ■Si; >>g' g & SS « 2-^ g S o b£ ^t*- o<^ « o ^ ^^ cDOO eOt-- »0— '^ i-H «5i raS S a o h •-■ 5 o S 73 «4H O o +J >, j: •»-> bS o (U « rr a ^ ^ CA o GO OOQO Oft THE CONTROL OF FLOODS BY RESERVOIRS. 195 I Ocot^ Ot^c o --H o '«*'" c^ i"C csf CD c^ "^ o r^ o (^^ CO r^ o oo ^^ o -^"r-^ '-^^ u:r '-^ o ioc^if5c^«coooiot~-ir5t^M«-^i>-r^t~*coiococo»ooo»oc^c^^ CO C^ O CO .-1 -^ CO C-COC^ T- 1 t~- o t^ "^" ■^"cc" CO Co"iO O iO io'»o"i0^io"»C~tr^io"u5"w3 lO lO"^ OCOr-Ot~*CDOO'*i— t00C0(Mc0<;Dt-^C<)O»-*-^00C0b-00t^00O t^'^coooooinO'*o-^<--coooi£:iiOic-^r-oo^ooci'-«c-(M lOOO^O i-^iO ■Tj'^OO r '-<^»0 -^COCO "«}<^»-' CO '-*I>.00 CO o »o C^ »C OOCO C^ ^ C> -^ C^ c^ cS ^C^ CO t>^C>-^tr^i-^ to ^ iO(M*OC^cD<00040^-lCt^'^'^t>-.t»t--.CO»OCO..-H oooooooooooooooooooooooooo Oc0r^Ob-O00Tj<^00C0(McOC0l^(NO'-<'*j-00t^00O b*'— •r0G000i0O'^(O.— ( — oooiciCOco-^^-co— ioocr-1— rt^CS lCC1U3M:OCOOOlOt>-iCt^"^'^t-^.'^l^CO»OCOCOW^OO»CC^C^'Tl oooooooooooooooooooooooooo OOt~-Ob-OOC^J Cir-C?i»CTj-^HOiiCiOOOOOO CO O CO C^ t^ lO lO oO'— "loosooom^oooo CO »-H OaO'-<0000»/5^H-^C^COCO»-tcO ^COOf-i C^C^ ^ 1-" (M C^ CO ^S3S23!i2555;9£S'^'~'C^^'^"5cor*ooc»o»-Oaos^HQ> ^ — 5 c:t: sji -^ "^ tc-a 2 2 C C^j3 ^ ^ o S C > ^_ ■3 S-^^ Sc^ £.5 o 5 -g^S g3^ g-S"^ £*« -3 >.o "-So g-23 S2^ — j=->^T3---^ S--t-i ^: "§ ° o = 2 ^ ^ ^ --D 2- ;iH^ ; d^ g c Co bC ; ;g §5 & g a&.c.S M'g J "I '-5 -s 3 '-5 -I J "c 1^ fe: "S O 3 tire's'— ^ Q.^ o "5 s^g■s^g•ilso£:§ _ „ J J " 2 -- =5-S ■ — 2 . be :3 - _^ M ; 'S-5 ,2 C-- S .-52 2 «" S> ■^_o „S ^~ g — — "S t C^-s c'S:3~=: o ajgg-§a||||i| I^S'^ it"^ gf 2|.S.s llJ^-pi«liil >.i"'s5'£B^'2S'sS2 S" g g-v g g^ °'- S>- g ^ o- cj tn 1-T3 X «T3 C-— Tei— " "B °'-E!{' c.sS c 2:^ £:: _ 'm 'S to ' m "^l ■" " o to J* :2.2S.s'o2.2'b2 M-^S^-t a 5 2 £25~o § 3 S 3 S '". -t. ■^. O- >• C > 1--3 in W6 WATER RESOURCES OF CALIFORNIA. > u O z z o V , V *j IM 4> ,', V U VM § u 3 .3 C o o O O o o o § <«!:: 1-4 M 00 n o s •0 CO V4-I Ml o O 4J >, ^ *J bD o u 9 DC a en U ft) ►^ S^2g E "o B >- O " C C "'S'V tj'^'S |li-s°|^£il|1g ^ L': c; ':c " 00 C^ 0000 -M »0 •-•C^ ^~* - E3S-S-C o S c = ^^ "S ^ 1- o ° S— t ° ^ S o S £ > ^ S en ^-StS « ^ o £ -o M J; "■SI ._'5 S o °^ " o. 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S T3 "m 3 XJ .-2-^ fa rt 03 a t3 03 J3 s a a o ■§3-^a'S-£D-s "^i^ air 151 g J a i SS3 ^^ 9S2^Sfc"io >^ m 2 ^ 0---.2 "=« t;3 22 "S 2-g rt.S SoS.a-v|aS2 c3 a bO - ^ ...oa a a -rt C5ofc_*-»— C3^ a °2 -a " o ■*^^ a 13 CO a.S !3"J3 •^ 03 !»■ 03~ 198 WATER RESOURCES OF CALIFORNIA. Performance of the four illustrative reservoir operating diagrams in controlling floods when coordinated with conservation. The last section of Chapter V describes the performance of the four illustrative reservoir operating diagrams in controlling floods. Tests are tabulated of their application to the records of all important floods on their respective streams. It was shown that reservoir operation in accord with these diagrams would provide more space than needed to detain the excess water of all floods of record and that the average space to spare while controlling all the large floods of record would have been about half the maximum reserve. In these computations, it was assumed that no water was released from the reservoir except as required by the diagrams. It may be observed in reviewing Plates XXIII to XXVI, inclusive, on which is delineated the reservoir stage while so controlling floods, together with the stage while controlling floods coordinately Avith conservation as described in this chapter, that at times the reservoir is needlessly full of water when operating for flood control alone, but when flood control is coordinated with conservation, it may be observed that the draft for useful purposes lowers the reser- voir level much of the time below that required for flood control only. At these times the space available for detaining flood water is increased over that resulting from the application of the diagram not coordinated with conservation. Although this extra empty space is variable in the time and amount of its occurrence, nevertheless, it is useful in detain- ing some flood water. Tables of unused reservoir space in controlling the floods of record when flood control and conservation are coordinated as described in this chapter, are prepared in parallel to those of Chapter V which tabulates the unused space in controlling the same floods by the same reservoirs and by the same reservoir operating diagrams but independently of conservation. A comparison of these tables sliows that coordination with conservation as herein described for the Kennett reservoir on the Sacramento River did not alter tlie minimum space to spare of 53,500 acre-feet on March 20, 1907, but did increase the average space to spare in controlling all the floods of record from 52 to 85 per cent of the maximum flood control reserve. Coordination with conservation in the Pardee reservoir on the Mokelumnc River, as described herein, increased the minimum space to spare in controlling the rain-water floods from zero to 6600 acre-feet and the average from 42 to 68 per cent of the maximum flood control reserve. It had no effect, however, on the unused space in controlling snow-water floods. On the San Joaquin River, the coordination of flood control and conservation in the Temperance Flat reservoir, as described herein, increased the minimum unused space in controlling the rain-water floods from zero to 74,500 acre-feet and the average fi-om 37 to 370 per cent of the maximum flood control reserve. It did not increase the minimum unused space in controlling the snow-water floods of record but did raise the average unused space from 53 to 111 per cent of the maximum space required. On the San Gabriel River, coordination of flood control with seasonal storage and a constant draft, as described herein, increased the minimum unused space from 12,700 to 32,600 acre-feet and the average unused space while regulating all the floods of record from 54 to 69 per cent of the maximum flood control reserve. THE CONTROL OP FLOODS BY RESERVOIRS. 199 KENNETT RESERVOIR ON SACRAMENTO RIVER. UNUSED SPACE WHILE CONTROLLING ALL FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM, 1895-1926. Reservoir Operated Coordinately for Irrigation with Incidental Power, and Flood Control. Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Maximum flood flow- uncontrolled Flow controlled to 125,000 second-feet maximum near Red Bluff Reservoir space not used in Mean daily flow near Red Bluff in second-feet Date reservoir nearest full controlling flood Date In acre-feet In per cent of maximum space required for flood control (454,000 acre- feet) Feb. 3, 1909 254,000 Feb. 4,1909 188,800 42 Feb. 2,1915 249,000 Feb. 2, 1915 200,900 44 Mar. 20, 1907 190,000 Mar. 21, 1907 53,500 12 Jan. 16, 1909 188,000 Jan. 18, 1909 191,400 42 Feb. 16, 1904 188,000 Feb. 16. 1904 357,700 79 Jan. 21, 1909 177,000 Jan. 21, 1909 150,700 33 Feb. 25, 1917 176,000 Feb. 25, 1917 761,400 168 Feb. 21, 1914 160,000 Feb. 21, 1914 119,600 26 Jan. 1, 1914 151,000 Jan. 2, 1914 926,300 204 Feb. 24, 1902 151,000 Feb. 26, 1902 289,100 64 Mar. 8, 1904 147,000 Mat. 8, 1904 332,400 73 Feb. 10, 1902 140,000 Feb. 12, 1902 528,400 116 Mar. 31, 1906 137,000 Mar. 31, 1906 105,500 23 Jan. 19, 1906 136,000 Jan. 19, 1906 1,158,800 255 Feb. 4, 1907 134,000 Feb. 4, 1907 433,500 95 Jan. 25,1903 131,000 Jan. 25,1903 431,700 95 Mar. 7, 1911 130,000 Mar. 7, 1911 368,400 81 Jan. 27,1896 128,000 Jan. 27, 1896 341,500 75 Average 385,500 85 \ 200 WATER RESOURCES OP CALIFORNIA. PARDEE RESERVOIR ON MOKELUMNE RIVER. UNUSED SPACE WHILE CONTROLLING TWENTY LARGEST RAIN WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM, 1904-1926. Reservoir Operated Coordinately for Municipal Supply with Incidental Power, and Flood Control. Height of dam 345 feet. Capacity of reservoir 222,000 acre-feet. Maximum flood flow — uncontrolled Flow controlled to 5,300 second-feet maximun. near Clements Reservoir space not used in Mean daily flow controlling flood In per cent of Date near Clements Date reservoir nearest full in 3econd-feet In acre-feet maximum space required for flood control (92,000 acre- feet) Jan. 30, 1911 16,700 Feb. 1, 1911 35.200 38 Mar. 19, 1907 15,310 Mar. 27, 1907 7,100 8 Jan. 26, 1914 11,100 Jan. 27, 1914 68,900 75 Jan. 14, 1909 10,400 Jan. 17. 1909 19,500 21 Feb. 21, 1914 9,850 Feb. 21, 1914 82,700 90 Feb. e, 1925 9,700 Feb. 6,1925 167,800 182 Jan. 1, 1914 9,250 Jan. 1, 1914 82,000 89 Jan. 21, 1909 8,400 Jan. 22, 1909 8,500 9 Mar. 20, 1916 8,040 Mar. 21, 1910 64,400 70 Feb. 2, 1907 7,860 Feb. 4, 1P07 79,300 86 Mar. 31, 1906 7,750 April 1, 1906 49,600 54 Mar. 23, 1907 7,610 Mar. 27, 1907 7,100 8 Jan. 22, 1914 7,470 Jan. 22, 1914 78,600 85 Jan. 18, 1921 7,350 Jan. 18, 1921 75,700 82 Mar. 7, 1911 7,210 Mar. 11, 1911 70,900 77 Nov. 21, 1909 7,200 Nov. 21, 1909 68,300 74 Feb. 11, 1919 7,060 Feb. 11, 1919 90,4C0 98 Jan. 19, 1906 6,960 Jan. 19, 1900 76,400 83 Mar. 12, 1918 6,940 Mar. 12, 1918 109,600 119 Aprilie, 1925 6,910 April 17, 1925 6,600 7 Average 62,400 68 THE CONTROL OF FLOODS BY RESERVOIRS. 201 PARDEE RESERVOIR ON MOKELUMNE RIVER. UNUSED SPACE WHILE CONTROLLING ALL SNOW WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM, 1904-1926. Reservoir Operated Coordinately for Municipal Supply with Incidental Power, and Flood Control. Height of dam 345 feet. Capacity of reservoir 222,000 acre-feet. Maximum flood flow- uncontrolled Flow controlled to 7,100 second-feet maximum near Clements Reservoir space not used in Mean daily flow controlling flood In per cent of Date near Clements Date reservoir nearest full in second-feet In acre-feet maximum space required for flood control (13,000 acre- feet) June 12, 1906 8,740 June 13, 1906 1,900 15 June 18, 1911 8,030 June 18, 1911 3,300 25 June 3, 1922 7,970 June 5, 1922 2,600 20 June 12, 1911 7,960 June 12, 1911 3,100 24 June 6,1911 7,880 June 6, 1911 4,000 31 May 31, 1922 7,770 June 1, 1922 6,700 52 June 1, 1915 7,750 June 1, 1915 10,000 77 May 18, 1922 7,670 May 19, 1922 1,800 14 June 16, 1906 7,600 June 17, 1906 4,500 35 June 10, 1917 7,550 Jane 10, 1917 2,900 22 May 24, 1911 7,500 May 24, 1911 800 6 July 4, 1906 7,480 July 4, 1906 1,100 8 Average 3,000 28 13-5:^111 202 WATER RESOURCES OP CALIFORNIA. TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. UNUSED SPACE WHILE CONTROLLING ALL RAIN WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM, 1907-1926. Reservoir Operated Coordinately for Irrigation with Incidental Power, and Flood Control. Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Maximum flood flow- uncontrolled Flow controlled to 10,700 second-feet maximum near Friant Reservoir spice net used in Moan daily flow controlling flood In per cent of maximum space required for flood control Date near Friant in second-feet Date reser vol r nearest full In acre-feet (133,000 acre- feet) Jan. 31, 1911 38,800 Feb. 1, 1911 538,000 405 Dec. 31, 1909 27,900 Jan. 1, 1910 260,300 196 Jan. 14, 1909 26,800 Jan. 15, 1909 853,400 642 Dec. 10, 1909 26,800 Dec. 10, 1909 418,100 314 Jan. 26, 1914 24,700 Jan. 26, 1914 811,700 610 Jan. 21, 1909 18,900 Jan. 22, 1909 751,400 565 Mar. 8, 1911 18,800 Mar. 8, 1911 344,700 259 Mar. 10, 1911 13,600 Mar. 10, 1911 310,200 233 Feb. 12, 1909 12,500 Feb. 12, 1909 631,800 475 Feb. 21, 1917 11,700 Feb. 21, 1917 321,700 242 April 6, 1911 11,600 April 6, 1911 141,900 107 Jan. 18, 1916 11,000 Jan. 18, 1916 414,500 312 Mar. 21, 1916 11,000 Mar. 21, 1916 74,500 56 Oct. 2, 1918 10,900 Oct. 2, 1918 775,000 583 Jan. 25, 1911 10,700 Jan. 25, 1911 735,900 553 Average 492,200 370 THE CONTROL OF FLOODS BY RESERVOIRS. 203 TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. UNUSED SPACE WHILE CONTROLLING ALL SNOW WATER FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM 1907-1926. Reservoir Operated Coordinately for Irrigation with Incidental Power, and Flood Control. Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Maximum flood flow- uncontrolled Flow controlled to 14,200 second-feet maximum near Friant Reservo'r space not used in Mean daily flow controlling flord In percent of Date near Friant in Date reservoir nearest full second-feet Id acre-feet maximum space required for flood control (177,000 acre- feet) June 13, 1911 23,100 Jane 23, 1911 21,100 12 Jane 4, 1909 22,800 June 8 1909 89,100 50 June IG, 1911 21,500 June 23 1911 21,100 12 July 7, 1911 19,500 Julv 7 1911 57,600 33 June 5, 1922 16,700 June 8 1922 417,100 236 May 22, 1911 16,200 May 23 1911 134,600 76 June 6, 1911 16,200 June 8 1911 165,500 94 May 8, 1909 16,200 May 8 1909 308,800 174 June 2, 1914 15,700 June 2 1914 167,500 95 June 5, 1912 15,300 June 5 1912 526,400 297 June 15, 1909 14,900 June 15 1909 95,000 54 June 27, 1911 14,700 June 28 1911 38,290 22 May 31, 1922 14,700 June 1 1922 575,000 325 June 24, 1909 14,600 June 24 1909 129,300 73 Average 196,200 111 204 WATER RESOURCES OF CALIFORNIA. SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. UNUSED SPACE WHILE CONTROLLING TWENTY LARGEST FLOODS OF RECORD BY RESERVOIR OPERATING DIAGRAM, 1895-1926. Reservoir Operated Coordinately for Flood Control, Seasonal and Over-year Storage. Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Maximam flood flow- uncontrolled Flow controlled to 1,900 second-feet maximum near Aziisa Reservcir sp.ce not used in Mean daily flow near Azusa in Date reservoir nearest full CO itroiling flood Date In per cent of second-feet In acre-feet maximum space reiiuircd for flood control (131,000 acre- feet) Jan. 18, 1916 22,300 Jan. 20, 1916 50,800 39 Dec. 19, 1921 16,000 Dec. 25, 1921 71,800 55 Jan. 1, 1910 12,500 Jan. 3, 1910 89,000 68 Fe)). 20, 1914 11,800 Mar. 1, 1914 64,500 49 Mar. 12, 1905 11,130 Mar. 14, 1905 94,000 72 Mar. 26, 1906 9,430 Mar. 29, 1906 32,600 25 Mar. 10, 1911 9,160 Mar. 14, 1911 71,400 54 Jan. 26, 1914 9,150 Jan. 27, 1914 111,600 85 Feb. 9. 1922 8,200 Feb. 13, 1922 104,300 SO Mar. 12, 1906 8,020 Mar. 13, 1906 103,400 79 Jan. 27, 19 IG 7,940 Jan. 30, 1916 42,600 33 Feb. 7, 1909 7,100 Feb. 8, 1909 118,100 90 Mar. 5, 1907 6,810 Mar. 11, 1907 89,900 69 April 1, 190.3 5,920 April 2, 1903 137,700 105 Dec. 27, 1921 5,900 Dec. 29, 1921 53,700 41 Jan. 29, 1911 5,260 Jan. 29, 1911 126,600 97 Jan. !8, 1914 5,110 Jan. 18, 1914 125,600 96 Mar. 11, 1918 5,030 Mar. 14, 1918 91,500 70 Jar. 10, 1907 4,670 Jan. 11, 1907 110,900 85 Jan. 31, 1911 4,220 Jan. 31, 1911 122,400 93 Average 90,600 69 The full tests are expressed graphically on Plate XXVII, "Per- formance of Reservoir Operating Diagrams in Controlling Floods of Record Coordinately with Conservation." The ratio of the empty reservoir space while controlling floods coordinately with conservation as described herein, to that actually necessary for control of the remainder of the flood was computed for eveiy day of stream flow record on each of the four illustrative stream^s. The ratios on each stream were arranged in order of increasing magnitude and the number smaller than each successive size counted. These counts were increased by pi'oportion to the number had the stream flow records been 100 years in length, and plotted on Plate XXVII. Smooth curves were drawn which indicate the ])r()hal)l(' frcupiency with which the empty space on hand at any time Avill approach the exact amount that should be on hand to insure the desired flood regulation. Superimposed on these are dashed-line curves transposed from Plate XXII, p. 96. These indicate the corres})onding relations in controlling floods when not coordinated with conservation. ('omparison is made in the following table of the probable number rtf days in ]0() years on which empty s})a('<' equal to or greater than the exact amount rccpiired for controlling floods would be provided in THE CONTROL OF FLOODS BY RESERVOIRS. 205 PLATE XXMI. 1 (0 KENNETT RESERVOIR 0> ON SACRAMENTO RIVER Capacity 2.940,000 ac. ft. lU M 1 — - --t— 17'iOOO ^er, ft 1 ■(5 F — 1- " ^ ^Reservoir operated coordmately for Irrigation with incidental power and Lt- "Reservoir operated for flood control alone, taken from Plate MS. {2 § — — — o o -lU- \\ c \ V tn \\ ^ \ V \ •s ^ — — — -'' L. <1> f= 100^ =s :^ 3 — ' — — — PARDEE RESERVOIR ON t^OKELUMNE RIVER Capacity 2??,000 ac ft — — -. • Ram water floods 5300 sec ft — 1- - Snowwater floods 7,100 sec ft. —Reservoir operated coordinatel> for municipal supply with incidental power v " alor e, ta ,n Irom t^lateAJUi. 1 — , - — 1 -J = X -10- " " j ii\ 1 1 i\\ T \ v Snow water floods -4- dentical for both _^ 1 \ V /|r ^ ^1^ pMg^ ■"',"','' . 1 1 :| ■lUU- II _ ^y ^:: ---. 1 i: Rain water floods^ ■' '::>.. Iv r-i •- res — — ' — — 0.1 100 0.1 100 ^ = SA N GABRIEL RESERVOIR ON SAN GABRIEL RIVER Capacity 180,000 ac ft. — 1,900 sec. ft. -1- 1 " eservoir operated coordinate!/ for ood control, constant draft of 72 ec.ft and variable summer drafts rom seasonal storage. 1 1 f 1 i___„ eservoir operated for flood control one, taken from Plate XXn. ' 1 ^ -lU- 1 1 1 w 1 L 1 I 1 I « * 1 .. . I — VV- 1 •100- - 1 1 ".\ \ ~ N ^ _ t , s •■■ », mk 4= !<.i^i TEMPERANCE FLAT RESERVOIR] ON SAN JOAQUIN RIVER Capacity 1,071, 000 ac ft 1 • Rain water floods I0,700sec.ft. -1- .. " Snow water floods I4,200secft. — Reservoir operated coordinately for irrigation with incidental power and flood control. ■"Reservoir operated for flood control alone, taken from Plate. JU. . ■ 1 — — \\0- t\ 1 l\ V \ \ N am water floods 4^*^ \. *•* ■ — .fc,^ f ■"-" - ^ ^^ »i 1 -- ^—{■ "■**n =s« !rrt- = I -t+t — U ' ^ I — rr~j'"/ it -"-4— « ; 1 ; = == fIJIII II 1141 :::^==44:fe;1 I 10 100 I 10 100 Ratio of reservoir space provided to that actually required. 1000 Performance of Reservoir Operating Diagrams in Controlling Floods of Record Coordinately with Conservation CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH RATIO OF RESERVOIR SPACE PROVIDED BY APPLICATION OF DIAGRAM TO THAT ACTUALLY REQUIRED FOR CONTROLLING FLOODS OF RECORD IS SMALLER THAN INDICATED. 206 WATER RESOURCES OP CALIFORNIA. the two instances. The probable frequency with which the dasired controlled flow would be exceeded downstream from the Kennett res- ervoir on the Sacramento Eiver, would be raised by coordination with conservation as described herein, from about one day in 80 to one day in 100 years ; downstream from the Pardee reservoir from about one day in 40 to one day in 50 years for rain-water floods with no change for snow-water floods; downstream from the Temperance Flat reser- voir from about one day in 30 to one day in more than 1000 years for rain-water floods, but with no change for snow-water floods ; and below the San Gabriel reservoir the frequency with w^hich the desired con- trolled flow may be exceeded would be increased from one day in 500 to one day in more than 1000 years. PROBABLE FREQUENCY WITH WHICH LESS EMPTY SPACE THAN FROM ONE TO TWO TIMES THE EXACT AMOUNT REQUIRED TO CONTROL FLOODS WILL BE PROVIDED. (Frequency in number of days in 100 years) . Fioud control coordinated with conser- vation as described in Chapter VI Flood control as described in Chapter V, not coordinated with conservation Rsservoiras described horcin Equal to that required Half again that required Twice that required Equal to that required Half again that required Twice that required Kennett 1 2 2.5 I.CFS than 0. 1 3.2 9 40 24 Less than 0.1 100 40 20 70 50 Lees than 0.1 150 50 1.2 2.5 2 5 3 2 3.2 5 12 GO 24 43 100 50 30 Pardee— Rain-water floods 100 Snow-water floods 50 Temperance Flat- Rain-water floods 70 Snow-water floods 150 San Gabriel 120 THE CONTROL OP FLOODS BY RESERVOIRS. 207 CHAPTER VII. CONCLUSIONS. Reliability of analyses. The system of flood analysis herein described, illustrated, and tested is entirely empirical. Although it is in accord with theoretic considera- tions, nevertheless, it does not rest upon hypothesis but rather is deduced directly from the past behavior of floods as shown by the records of their measurement. But one assumption is employed, namely, that whatever relation that may exist between the time of year, the occasion and the size of flood occurrence, should be contained within existing stream-flow data. In order to discover this relation, the usual distinction between flood and normal flow is omitted. The relation between time of year, occasion and size of occurrence is sought for flows of all magnitudes contained in the measured record with the expectancy that this relation, when found, may be extended to disclose the circumstances under which flows of extraordinary size may occur, flows larger than are contained within the stream flow records or are evidenced by high water marks or dimensions of existing flood channels. In seeking this relation interest is not centered in average occurrences as in many engineering investigations, but rather in the limiting con- ditions of flood occurrence. The safety of lives and property require that works for flood protection be designed for exceptional rather than average conditions, otherwise, the flood menace would not be removed. Therefore, the analyses take the form of discussions of the frequency with which various size flows occur at different times of the year and with different amounts of seasonal precipitation up to the time of their occurrence. The limiting conditions of flood occurrence about which knowledge is desired, are the circumstances under which the very infrequent flood,s occur. The limits in time of year and in the amount of previous rainfall with which extraordinary stream discharge occurs, are sought through the development of curves expressing the average frequency of past occurrences. It was found by trial that the data expressing the relation between size of flow and average frequency of its occur- rence plot on fairly smooth curves of similar shape for all California streams on which continuous measurements have been made. While most of the data from which these curves are developed concern ordinary events, as they happen less frequently they approach the extraordinary. By the extension of these curves beyond the limits of the plotted data, the frequency may be anticipated of events so extraordinary that not even a single one is contained within the period of record. By this system of graphical analysis, estimate is made of 208 WATER RESOURCES OF CALIFORNIA. Avhat the records Avould disclose were they many times longer than they actually are.* The inclusion in these anah'ses of all data on stream discharge without distinction between flood and normal flow multiplies many times the number of data available to guide the drafting of curves of relationship. In a record of stream flow, say thirty years long, there may be from three to six thousand entries of daily flow while the entries customarily regarded as floods may be limited to perhaps from fifteen to thirty. Thus, in the system of analyses herein employed, a large volume of data defines with considerable certainty that part of the curves of relationship pertaining to usual occurrences so that the trend of the curves is established as they approach the zones of infrequent occurrence into which they are extended. AVhether or not stream discharge follows sufficiently definite rules to warrant the close consideration herein given was seriously questioned at the time the Avork was started. For this reason, the first eft'ort held to a comparatively simple scheme of analysis. Working with an appre- ciation that the subject is not one favorable for exactness, two efforts were made before the subject could be adequately gauged. While a casual review of the work as finally completed is not entirely convincing that the great volume of detail with which the subject has been pursued, is warranted, yet, to those who have taken part in the intricate com- parisons, it became evident before proceeding very far. that much of the apparent scattering of plotted points on the diagrams is the result of the small amount of data on infrequent flows contained in the com- paratively short period of stream flow record in California, rather than of inconsistencies in relationship. The relationship under study pertains only to the average frequency of occurrence without regard to the sequence of events, so that, in plotting the data, frequencies were assigned neces.saril}- based upon the number of times events occurred within the period of measured record. The infrequent events that * Inasmuch a.s thi.s entire work is an analysis of the historical trend of flood occurrence, as disclosed by the period of measured stream flow record, it is of mterest to discover if possible to what extent discordant events may be expected to occur. In reviewing this possibility among rainfall data that antedate stream flow records by some 30 or 40 years, it was observed that the sea.sons 18S3-4 and 1889-90 m southern California were very unusual. Both had more than double normal precipitation while the largest season during the period of measured run-off had barely .50 per cent more than normal precipitation. Also the season 1883-4, as dis- closed by the records at Los Angeles, was unusual in having a storm of 2.32 inches in two day.s during the fore part of April, while the season 1889-90 was extremely unusual in the volume of fall precipitation, it aggregating by January 1, 1890. 62 per cent in excess of the total for a normal season. A detail study of the daily precipita- tion of these two seasons shows that, had the reservoir operating diagram for the San Gabriel River been in use, there might have been technical failure in its operation by the reservoir filling and some water passing over the spillway to augment the rontrolled flow below the reservoir, however, no reason was found to suppose that this quantity would have been large enough to be serious. It is evident from study- ing the records that both of these seasons had unusual features that depart materially from the trend of the period of measured run-off so that some modification of the reservoir operating diagram for the San Gabriel River, as herein presented, would probably be required if it were desired that the operation of the diagram be tech- nically perfect in these two seasons and run-off records were at hand to work with. Run-off data collected on the four illustrative streams since the close of the analyses contained in this bulletin have also been reviewed for discordant events. It was found that all floods, including that of March 2.'')-27, 1928, would have been controlled as anticipated. The flood of March 25-27. 19 28, on the Mokelumne River, however, exceeded the once-in-SO-year value which, by construction, the diagram is not expected to control. Therefore, the empty space provided by the diagram fails to control this flood under direct test. Nevertheless, with flood control and conserva- tion coordinated as described herein, this flood would have been controlled to the specified maximum flow by reason of the additional empty space provided by the drawdown resulting from normal conservation draft. THE CONTROL OF FLOODS BY RESERVOIRS. 209 occur but once or twice within the period of record, are thus accorded an average standing that may or may not be actually theirs. It is apparent that the occurrence of these infrequent events within the. years during which stream flow measurements happened to be made, is much a matter of circumstance since there appears to be no orderly sequence in the size of stream flow. When longer records of stream flow become available, no doubt many of these events will be found to per- tain to quite different average intervals than those herein assigned. With this viewpoint in mind, positions on the diagrams were found for the curves and parts of curves representing infrequent events that are logical in relation to the plotted data but that appear in places to be out of sympathy with some of them. Whether or not the interpretations are correct can not be foretold. Greater length of stream flow record alone can furnish the means of improving these interpretations of the data. In the meantime the results of the analyses should be employed Avith judgment. The four reservoir operating diagrams, constructed as a conclusion of the anal.yses described herein, are tested against the entire period of stream-flow record on their respective streams at the close of Chap- ters V and VI and are found to be entirely adequate for controlling all floods of record. In fact, for the most part, more than half the space provided by the diagrams for detaining excess flood water is seldom used in these tests. Even the largest floods of record do not require the entire reserve to detain their volume of excessive flow. Although in engineering practice, test against the period of record is often deemed sufficient to determine the reliability of performance of proposed control w^orks, nevertheless, it is thought that a particular advantage of the system of analysis herein described is that it affords the means of designing flood control works not only adequate for all occurrences of historical record but adequate, to the degree selected, for future expectancies as disclosed by the trend of the historical record. It is of interest to note, for instance, in connection with the reservoir operating diagram for controlling floods on the San Gabriel River when employed in the "Coordinated Plan," that only three-fifths of the 131,000 acre-feet of maximum flood control reserve is filled while controlling the largest flood of record to 1900 second-feet, and that only one-third of this maximum reserve is filled on an average in so control- ling the twenty largest recorded floods. This reservoir operating dia- gram was designed to control floods larger than have occurred wdthin the period of record. For this reason the floods of record do not fill the entire reserve. A safety factor either greater or less than indicated l)y the above figures could have been introduced in the diagram at tlie time of its construction if it were thought desirable. In response to the question as to what would happen if several large floods should follow one another, the largest flood of record in each calendar month from December to April on the San Gabriel River was selected and they were assumed to follow one another, each occurring on its actual calendar date under the conditions of recorded precipita- tion but transposed to a hypothetical year. The transposition was made from one year to the other on the day before the first rapid increase in flow of the next flood. By test against this series of floods, 210 WATER RESOURCES OF CALIFORNIA. the San Gabriel diagram was thus found to be adequate to control in succession the floods of December, 1921, January, 1916, February, 1914, March, 1905, and April, 1926. It may be concluded, therefore, that the reliability of the system of analyses herein described is essentially dependent upon the extent to which the future will repeat the past. If it does and the years of stream flow record at hand disclose the past correctly, then the deduc- tions of these analyses are reliable. If it does not, the deductions involve the same error that is contained in all other hydraulic estimates of common use. The foundation of all engineering rests upon the expectancy of a repetition of past events under like circumstances in the future. Many millions of dollars are spent annually and whole cities are erected upon this assumption. Without it practical engineer- ing could not progress. The nineteen to thirty-one years of stream flow measurement upon which the illustrations of this volume are based, furnish a longer record than is available in many instances for hydraulic design. The lack of data often makes it necessary to base hydraulic design on rather brief stream flow records and sometimes none at all. Because these illustrations are based upon the longest records of stream flow in the state, it is believed that they have a stronger claim for accuracy than most work of the kinrl. Therefore, the analyses of this volume are presented as illustrative of principles relating to the control of floods by reservoirs adequately reliable in their essential features for practical application, if judgment is employed. Although the reservoir operating diagrams are presented as a culmination to these analyses, nevertheless, it is not intended that their features should be applied indiscriminately. They are presented as illustrations and their features should be adjusted to the necessities of each specific instance in order to secure good results. Accuracy of analyses. p]ssentially speaking, the accuracy of the analyses contained herein is dependent upon the correctness of the rainfall and stream gaging records employed. It is commonly known that the cost of gaging streams with exactness is prohibitive for general work. On the other hand, experience in ('alifornia indicates that for the most part, the records of the United States Geological Survey that have been used exclusively in this work, are substantially correct. To .seriously affect the analyses there would have to be an error in either tiie observations of rainfall or stream flow continuing through years of time, or in the i-ecords of the larger floods that east the greater influence in the exten- sion of the curves of the several diagrams. This volume is prepared with full acceptance of the stream gaging and rainfall records as pub- lished or in pi-ei)ai-ation for publication by the federal bureaus. It has been left to the judgment of whoever may utilize its cont(>nts, to intro- duce such safety factor in this res])ect as may be deemed desirable under the circumstances at the time of use. Attention has been ]ilaced on ])io lucing a woi'k thai would mak(> tliis |)ossible. Effect of length of stream flow record upon the accuracy of deductions. In reviewing the analyses described in this volume, it may seem rather bold to at1<'iiipt to ])i-('di('t tlie vast future from tlie trend of THE CONTROL OF FLOODS BY RESERVOIRS. 211 occurrences during the past 15 to 30 years, yet, there appears to be no alternative, if such knowledge is desired, until sufficient time has elapsed from the beginning of systematic records for the accumulation of more data. Systematic measurements of California streams started in 1895, only thirty-two years ago. It was some time, however, before many streams were included in the program, so that there are now only a few that have been measured for more than twenty years. Fortu- nately, as closer settlement and larger property values urge greater accuracy in flood analysis than can be attained at present, the expe- rience of additional years will be at hand for more perfect analyses than .can be attained with present information. In the meantime, judgment must be employed in the application of the best analyses possible of available data. In order to throw some light upon the extent to which the length of stream flow record affects the required reservoir space for controlling floods indicated by these analyses, Plate XXVIII, ' ' Effect of Omission of the First Half of the Years of Record that Contains Five of the Largest Floods on Indicated Reservoir Space Required to Control Floods on Sacramento River near Red Bluff," has been prepared. It illustrates the variance in deductions that may be made from two records, one half the length of the other and containing only the lesser floods. The anah'sis .shown in black is taken from Plate X of Chapter IV. It employ's the entire thirty years of record on the Sacramento River. Superimposed in red is an analysis of the last fifteen years, similar in all respects to the first except that it employs only the half of the record subsequent to the historic flood years of 1907 and 1909. It may be observed, in the part of the plate relating to the data used in constructing Plate XVIII, "Reservoir Operating Diagram for Con- trolling Floods on the Sacramento River," that the difference in the maximum flood control reserve determined by these two analyses, is 15 per cent. Geographical limitations of system of analysis. Since the entire analysis herein presented is empirical and has been developed and tested entirelj^ from data on California streams, it is not known to w^hat extent it may be successfully applied in other localities. No doubt the definite limits to the flood season found in these analj'ses bear some relation to the sharp demarcation between the wet and dry seasons, one of the distinctive features of California climate. Since this distinct wet and dry season is the reason for conserving flood waters in California, it seems probable that the double use of the same reservoir space for both flood control and conservation Avould not be of such economic importance if climatic conditions were different. There- fore, it can not be said, without extended inquiry which has not been made, to what extent the system of analyses herein described applies to localities of less marked wet and dry seasons than California. The discussion herein presented is of California conditions. Future possibilities of improving proposals for control of floods by reservoirs. The proposals for controlling floods by reservoirs described herein all pertain to single reservoirs. At the time of preparing this work, a large program of reservoir construction is in its inception in California. 212 WATER RESOURCES OF CALIFORNIA, PLATE X.W'III, Reservoir space in per cent of greatest daily run-off of once-in-25-year flood (493,800 acre feet) _ - — o o 3 _ O O O - — O O O CK Nu .1 mber of da 1 ys in OOjyearsc 10 )n whic 100 n reservoir 1,000 space is exceedec 10,000 100 = , _ ! Maximum controlled t low 000 E ' °75^rffl5e»nd.eef ■■ 10 24,900 20 49,800 30 74,700 o 40 99,600 50 124,500 '^ 60 149,400 70 174,300 -.-. ■:::= = = . "4—. --^ = = = ";;;'^s "^-a.; !s;i 1 — 1 1 1 1 1 rn 1 — i—i-rrrn --• 10%-HVIaximum controlled flow "^^v. ». - '^^ ■■»i»i ""*^»« ^v In N fei iii5 = ?-: l T > ^0 f.l N- 4--^^;= S"^^""^ -!f^l zzt M \ N^ 'i ^^ '**^ ; M-i^d> \ \ -!v^^. I'A V ^ — - 1 1 I--- p R = : :-:-: \t \70^ 1 -4^' 1 1 — - --- .. " ± — : — , .. Indicatee Effect of Omission OF THE First Half of the Years of Record ^T Contains Five of the Largest Floods ON ) Reservoir Space Required to Control Flo( 3DS ON Sacramento River near Red Bluff BLACK CURVES -ANALYSIS OF RECORDS 1895 TO 1925 RED CURVES- ANALYSIS OF RECORDS 1910 TO 1925 (FLOODS OF 1904,1907 AND 1909 OMITTED) CURVES SHOW NUMBER OF DAYS IN 100 YEARS ON WHICH RESERVOIR SPACE GREATER THAN INDICATED IS NEEDED TO CONTROL FLOODS TO SPECIFIED MAXIMUM FLOW. Maximum controlled flow expressed in per cent of greatest daWy rate cfflow of a once-in-25-^ear flood i411— Page :ill' THE CONTROL OF FLOODS BY RESERVOIRS. 213 Since this program must necessarily be constructed progressively, the possibility of coordinating flood control by reservoirs and conservation is illustrated herein in its relation to the first installment of this large reservoir construction program. The examples worked out demonstrate that the first units of this large reservoir construction program may be used to control floods without interference with conservation values. However, as time goes on and more than one large reservoir is con- structed on each stream, the flood control reserve may be divided among several reservoirs instead of being allocated entirely to one as in the illustrations herein. In doing this, either a greater degree of flood control may be efiPected by enlarging the total reserve or the possibility of interference with conservation may be made even more remote than in the proposals herein described and tested by dividing the reserve without enlargement among several reservoirs. The proposals for the control of floods by reservoirs may be still further improved as years pass by, since stream flow data covering longer periods of time will be at hand. The added data will permit new analyses to be made that will offer greater assurance of accuracy than is possible at present and through closer study made possible by additional data, no doubt improvements may be devised in the con- struction of the reservoir operating diagrams. It is certain that much improvement may be made in the part of the diagrams pertaining to snow-water floods. In the analysis herein, the part of the diagrams pertaining to snow- water floods is constructed using indices of rainfall. Since snow-water floods pertain more to the amount of snow-on-the-ground at any time, rather than upon the total of previous seasonal precipitation, it is evi- dent that, were data of snow-on-the-ground available, superior results could be obtained. This is indicated on Plate XXIV, p. 119, and Plate XXV, p. 131, which show the effect on reservoir stage of controlling floods on the Mokelumne and San Joaquin rivers by the reservoir operating diagrams described in Chapter V. In reviewing these plates, it is noticeable in many instances, that space is held in reserve for flood control during the latter part of June and the first part of July, when, by the indications of subsequent stream flow, the snow in the mountains must have been too far melted to produce floods. Since these reservations of reservoir space are held nearly to the close of the run-off season, they result in the reservoir failing to fill to the point that it otherwise would, had space not been reserved for flood control, and cause a slightly reduced yield thereby. While in these two instances the differences in reservoir yield with and without flood control are small, nevertheless, it is believed that a noticeable improvement could be made in the part of the work relating to snow-water floods, if data relating to snow-on-the-ground were available. It is believed that superior results could be obtained by constructing the pai't of the reservoir operating diagram relating to snow-water floods upon indices of snow-on-the-ground instead of upon indices of precipitation. The rainfall indices apparently indicate the general character of the season fairly well so far as rain-water floods are concerned, but, in failing to incorporate the effect of weather conditions subsequent to precipitation upon the amount of unmelted snow remaining on the ground, lead to the unnecessary reservation of reservoir space for the control of snow- 214 WATER RESOURCES OF CALIFORNIA. water floods almost up to the close of the run-off season. If indices of snow-on-the-!?round at some suitable mountain .station were used both in consti-uctinj? and a])i)lying the pai't of the reservoir operating dia- grams relating to snow-water floods, the Pardee and Temperance Flat reservoirs undoubtedly would have filled to the .same point each year both with and without flood control and there would not have been even the slight reduction in reservoir yield with the inclusion of flood control that is noted in the tests of the reservoir operating diagrams on the.se two streams. (See pp. 121 and 130.) Indices of snow-on-the-ground could not be used in constructing the reservoir operating diagrams for the Mokelumne and San Joaquin rivers because records suitable for this purpose are not available. So far as known, the only records of snow-on-the-ground of anj^ length are at points in the Sacramento River drainage basin. Since snow melts earlier in the season in the Sacramento than in the San Joaquin basin, these records are not adapted for use on the Mokelumne and San Joaquin rivers. THE CONTROL OP FLOODS BY RESERVOIRS. 215 CHAPTER VIII. TABLES OF MONTHLY SUMMARIES OF WATER AND POWER YIELD OF RESERVOIRS ON THE FOUR ILLUSTRATIVE STREAMS. Yield computed on a daily basis to show the effect of inclusion of the flood control feature upon the yield of the "Coordinated Plan." KENNETT RESERVOIR ON SACRAMENTO RIVER. Table Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. No. Page Assumptions employed in computing water and power yield 216 la. Operating primarily for power generation with incidental irrigation. With and without flood control by reservoir operating diagram 218 2a. Operating primarily for irrigation with incidental power generation. With and without flood control by reservoir operating diagram 234 3a. Operating primarily for irrigation. Comparison for two methods of flood control 250 4a. Operating primarily for power generation with incidental irrigation. Comparison for two methods of flood control 266 5a. Summary of power yield. With and without two methods of flood control 282 PARDEE RESERVOIR ON MOKELUMNE RIVER. Height of dam 345 feet. Capacity of reservoir 222,000 acre-feet. Assumptions employed in computing water and power yield 298 6a. Yield with and without flood control by reservoir operating diagram 300 7a. Comparison of yield for two methods of flood control 312 8a. Summary of yield in water and power with and without flood control 324 TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Assumptions employed in computing water and power yield 331 9a. Yield with and witliout flood control by reservoir operating diagram 332 10a. Comparison of yield for two methods of flood control 342 11a. Summary of yield in water and power 352 SAN GABRIEL RESERVOIR ON SAN GABRIEL RIVER. Heights of dams 383 and 425 feet. Capacity of reservoirs 180,000 and 240,000 acre-feet. Assumptions employed in computing water yield 358 12a. Yield under "Coordinated Plan." Flood control and seasonal storage coordinated. Capacity 180 000 and 240,000 acre-feet 360 13a. Yield under "Coordinated Plan." Flood control and seasonal and bvei'- year storage coordinated. Capacity ISO.OOO and 240,000 acre-feet 382 15a. Comparison of yield for two methods of flood control. Flood control coordinated with seasonal and over-year storage. Capacity 180,000 acre-feet 404 IGa. Comparison of yield for three steps in coordinating the use of reservoir space. Capacity 180,000 acre-feet 426 17a. Comparison of yield operating for flood control and constant draft only. Capacity 180,000 and 240,000 acre-feet 448 216 WATER RESOURCES OF CALIFORNIA. ASSUMPTIONS EMPLOYED IN COMPUTING WATER AND POWER YIELD OF KENNETT RESERVOIR ON SACRAMENTO RIVER ON DAILY BASIS. 1. Water supply at dam site is the flow at the Ked Bhiif gaging station of the United States Geological Survey unimpaired by upstream diversions, less 25.9 per cent which is estimated to originate on the average on the drainage area between the dam site and gaging station, and less the unimpaired flow of the Pit River at Bieber. No deductions are made for prior rights downstream from the dam. 2. Daily stream flow at the dam site on any day within a month bears the same relation to the monthly mean at the dam site as the measured mean daily discharge of the same date at the Red Bluff gaging station of the United States Geological Survey bears to the corresponding measured monthly mean at this station. 3. The reservoir is full on June 1, 1895, the opening date of the estimates. Run-off index of season 1894-1895 is 12-4. The reservoir fills in 1925 with a run-off index of 81. 4. The net evaporation from the reservoir surface equals 3.5 feet depth per annum, divided among the months as follows : Depth in Per cent of Month feet seasonal total April 0.32 9.2 May 0.44 12.G June 0.52 15.0 July 0.62 17.8 August 0.58 16.6 September 0.45 12.7 October 0.34 9.6 November 0.23 6.5 3.50 100.0 5. The total seasonal demand for irrigation water is divided among (he months as follows: Demand in per cent of total Month seasonal use January February March 1 April May 16 June 20 July 22 August 20 September 12 October 4 November December Total 100 6. The seasonal irrigation yield is that which can be obtained during the period witii a deficiency on the average not oftener than one year in ten. 7. Power is generated at a plant near the base of the dam with a power factor of 0.80 and load factors as noted. THE CONTROL OF P'LOODS BY RESERVOIRS. 217 8 Primary power yield is the eneroy that can be generated without fail through every season from 1871 to 1926, divided among the months as lOilOWS : Electric power con- sumption in per cent of annual total (state- wide i,r *T average) Month r- o Januai-y ~~"~ q'^j February ~ ^ 8 March ,j-'g April ZZIIIIIZIIII 8 8 May -__- - _ 9;o June __ ^4 July c)5 August g^Y September g',^ October g'g November g"o December '2, „, , T . 100.00 Total 9 The secondary power vield is the energy that can be generated intermittently by the installed capacity of the power plant m addition to the primary output. , . n 10 The overall plant efficiency is 75.0 per cent at full reservoir level, increases to 77.4 per cent at 0.8 depth and then decreases to 75.0 per cent at 0.6 depth of a full reservoir. ,,,r.r.nf^ i 11 The elevation of the tail race rises 26 feet when 100,000 second- feet are passing the dam, 17 feet when 50,000 second-feet are passing, 10 feet when 25,000 second-feet are passing and corresponding amounts for other floAvs. ' ' 14—52411 218 WATER RESOURCES OF CALIFORNIA. TABLE la. KENNETT RESER WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Esti- mated run-off Wifhouf flocd control Year and month Stage of Power dr.ift .\verage power yield at dam reservoir at through turbines in acr!-feet Evapora- Waste over .Average in kilowatts (Load factcr~0.75) site in acre-feet beginning of month in acre-feet tion in acre-feet spillway in acre-feet power head in feet Primary Secondary ♦Primary Sscondgry Total 1896 Jan. 1,980,000 2,256,000 238,000 98,030 960,000 389 97.400 40,500 137.900 Feb. 474,000 2,940,000 218,000 173.000 83,000 408 98.400 78.000 176,400 Mar. 738,000 2,940,000 245,000 21.5.000 278,000 410 101,200 91,100 195,300 April 891,000 2,940,000 249,000 231,000 7,000 404,000 408 109,000 101.000 210,000 May 1,194,000 2,940,000 279,000 219,000 10,000 68'J.OOO 407 117,500 92.500 210,000 June 53'i,000 2,940,000 283,000 196,000 12,000 80,000 410 124,200 85.800 210,000 July 313,000 2,905,000 298,000 151,000 14.000 407 125,400 63.700 189.100 Aug. 268,000 2,755,000 301,000 102,000 13,000 400 126,700 42.500 169,200 Sept. 258,000 2,604,000 282,000 101,000 10,000 394 120,000 42,800 162.800 Oct. 282,000 2,469.000 278,000 75.000 7,000 388 113,400 3 3,. =00 143.' 03 Nov. 472,000 2,371,000 264,000 161,000 5,000 385 110,300 63.800 177.100 Dec. Total or average 920,000 2,413,000 267,000 246,000 392 109,400 100.600 210,000 8,306,000 3,205,000 1,968,000 78,000 2,491000 400 113,000 69,500 182.500 1897 Jan. 577,000 2,820,000 220,000 129 000 99,000 412 97,400 55,000 152,400 Feb. 1,338,000 2,940,000 218,000 231,000 889,000 408 101.900 108.100 210,000 Mar. 737,000 2,940.000 247,000 251,000 23:1,000 407 104.200 105.800 210,000 April 8.58,000 2,940,000 249,000 231.000 7,000 371,000 408 109.000 101.000 210,000 May 551,000 2,940,000 276,000 195,000 10,000 73,000 411 117.500 82.500 200,000 June 310,000 2,940,000 283,000 73.000 12,000 410 121.200 32.100 156.300 July 2/5,000 2,882.000 298,000 90.000 14,000 407 125,400 37.900 163.300 Aug. 254 000 2,755.000 305,000 87.000 13,000 400 126,700 3"),200 162.900 Sept. 247,000 2,604.000 282,000 90,000 10,000 394 120,000 38,200 1.58.200 Oct. 262,000 2,469,000 278.000 75,00(1 7,000 388 113,400 39.500 143,900 Nov. 274,000 2.371,000 265.000 97,000 5,000 382 110,300 40.300 1.50,600 Dec. Total or average 366,000 2,278,000 274,000 3.204.000 113,000 1,671,000 380 401 10.9,400 113,400 45.200 154,600 6,052,000 1,662,000 78,000 59,100 172,500 1898 Jan. 257,000 2,2,57,000 213,000 (1 (1 380 97,400 97,400 Feb. 478,000 2,271,000 226.000 (1 388 101.900 101, '.00 Mar. 380,000 2.523,000 218,000 397 104,200 101.200 April 274,000 2,655,000 253,000 7,000 400 109.000 109.000 May 300,000 2,669,000 281,000 (1 10,000 401 117.500 117.500 June 301,000 2.678,000 287,000 11,000 401 121,200 124,200 July 237,000 2,681,00(1 301,000 14.000 400 125,400 125,400 Aug. 225,000 2,606,00(1 307,000 (1 12.000 316 126.700 126,700 Sept. 198,000 2,512,000 2St.()(IO 9,000 390 120.000 120,000 Oct. 221,000 2,417,000 279,000 (1 7,00(1 386 113.400 113,400 Nov. 217,000 2,352 000 265,000 21,000 5,000 383 1 10.300 8,890 119,100 Dec. Total or average 217,000 3,308,000 2.278.000 274.000 3,248,000 21.000 380 392 109.400 113,400 700 109.400 75.000 114.190 1899 Jan. 605.000 2,221,000 23.1,000 (1 388 97,400 97,400 Feb. 253.000 2.587,000 222,000 (1 398 101,900 ioi,roo Mar. 900,000 2,618,000 219,000 65,000 264,000 404 104,200 27.300 131.500 April 456,000 2,940,000 217,000 174.000 7,000 28,000 411 109,000 76,300 185.300 May 330,000 2.940.000 276.000 44.000 10.000 412 117,500 18.800 13 -..300 June 302,00(1 2,910,000 'JS'.'.OOO 5'),011(l 12,000 7,000 411 121.200 25.700 149.900 July 210.000 •> SS2.000 218.000 5.i,0(l(l 1 1,00(1 407 125,400 23.100 118.500 Aug. 221,000 2,7.55,000 301,000 5H,000 13 0011 400 126,700 21.200 1.50.900 Sept. 197,000 2.601,000 282.000 40,000 10.000 394 120,090 16.900 13). 000 Oct. 252.000 2.469.000 278 00(1 65.000 7 00(1 388 113,400 2i,.500 131.C00 Nov. 645.000 2.371.000 261.000 187,000 5,000 381 110 300 77.900 188 200 Dec. Total or average 646,000 5,0.50,000 2,560,000 265,000 243.000 990,000 78.000 299,000 398 400 109.400 100,600 210,000 3,206,000 113.400 31,900 148,300 ♦Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 219 VOIR ON SACRAMENTO RIVER. POWER GENERATION WITH INCIDENTAL IRRIGATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Daily Basis. mary, see Table 1, page 108.) Installed capacity of power plant 400,000 k.v.a. P. F. = 0.80 Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125 000 sec.-ft Alaximum reservcnr space required 4o4.000 ac.-ft. Stage of reservoir at Power draft through turbines in acre-feet Evapora- tion in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Average power head in feet Average power yield in kilowatts (Load factor^O.75) Year and month of month in acre-feet Primar.v Secondarj- ♦Primary Secondary Total 1896 2,256,000 242.000 118.000 1.357,000 383 97,400 47,200 144.600 Jan. 2,509,000 231.000 51,000 50,000 396 98,400 22.300 120.(00 Feb. 2,651,000 247.000 49,000 153.000 405 104,200 20,400 124.600 Mar. 2.940.000 249.000 231,000 7.000 404,000 408 109,000 101,000 210,000 April 2,940.000 279,000 219.000 10.000 686.000 407 117,500 92,500 210.000 May 2,940.000 283.000 196.000 12.000 80.000 410 124,200 85,800 210,000 June 2,905,000 238.000 151.000 14.000 407 125,400 63,700 183.100 July 2 755.000 304.000 102.000 13.000 400 126,700 42,500 169.200 Aug. 2,604,000 282,000 101.000 10.000 394 120,000 42,800 162,800 Sept. 2.46,1,000 278,000 75,000 7.000 388 113,400 30,500 143,900 Oct. 2,371.000 264.000 161,000 5.000 385 110,300 66.800 177.100 Nov. 2,413.000 268,000 247,000 223,000 330 109,400 100,600 210.000 Total or 3.225,000 1,701,000 78,000 1,640,000 1,323.000 398 113,000 59,700 172,700 average 1897 2.595.000 238,000 174,000 252.000 o92 97,400 71,000 168,400 Jan. 2..508,000 228.000 242.000 846.000 385 101,900 108,100 210,000 Feb. 2.530.000 251.090 130.000 75,000 398 104,200 53,200 157,400 Mar. 2.811,000 249.000 186,000 7,000 2.000 285.000 408 109,000 81,400 190,400 ^r'' 2 940,000 276.000 195,000 10 000 73.000 411 117,500 82.500 200.000 May 2.940,000 283.000 73.000 12.000 410 124,200 32,100 156.300 June 2.882.000 298.000 90,000 14.000 407 125.400 37,900 163.300 July 2,755.000 305.000 87.000 13.000 400 126,700 38.200 162.900 Aug. 2 604.000 282,000 90,000 10.000 334 120,000 38,200 158.200 Sept. 2,469,000 278.000 75.000 7.000 388 113,400 30..500 143.900 2,371,000 265.000 97.000 5,000 382 110,300 40,300 150,600 Nov. 2,278,000 274.000 113.000 380 109,400 45.200 154,600 Total or 3,227,000 1,552,000 78,000 1.175,000 358,000 396 113,400 54,300 167,700 average 2,257,000 243,000 380 97,400 97,400 1898 Jan. 2,271,000 226,000 388 101,900 101,900 Feb. 2.523.000 248,000 337 104,200 104,200 Mar. 2,655.000 253,000 7,000 400 109,000 109,000 April 2,669,000 281,000 10,000 401 117,500 117,500 May 2,678,000 287.000 11,000 401 124,200 124,200 June 2,684,000 301.000 14.000 400 125.400 125,400 July 2,606.000 307.000 12.000 336 126,700 126,700 Aug. 2,512,000 284.000 9.000 330 120,000 120.000 Sept. 2.417.000 279.000 7.000 386 113,400 113.400 Oct. 2.352,000 265.000 21,000 5.000 383 110,300 8,800 119.100 Nov. 2,278,000 274.000 380 109,400 109.400 Dec. Total or 3,248,000 21.000 75.000 392 113.400 700 114.100 avcrjge 1899 2,221,000 241,000 45.000 2,000 387 97,400 18,400 115.800 Jan. 2.538,000 223,000 396 101,900 101.900 Feb. 2.568,000 219.000 57.000 278.000 399 104,200 23.900 128.100 Mar. 2,884,00C 246 OCO 140.000 7.000 7,000 412 103,000 61.500 170.500 April 2,940,00(] 276.000 44.000 10.000 412 117..500 18.800 136.300 May 2,940,O0C 282.000 53.000 12.000 7,000 411 124,200 25.700 149.900 June 2.882,0!)C 298.000 55.000 14.000 407 125,400 23.100 148.500 July 2,755.000 304.000 58.000 13.000 400 126,700 21.200 150.900 Aug. 2.604.09C 282.000 40,000 10,000 334 120,000 16.900 136.100 Sept. 2.469.00f 278.000 65,000 7.000 388 113,400 26.500 139.900 Oct. 2.371,O0C 264.000 187.000 5,000 386 110..300 77.900 188.200 Nov. 2.550.000 266.000 244.00) 994.000 108.000 396 399 103.400 100.600 210.000 148.400 Dec. Total or 3,203.000 78.000 388.000 14,000 113.40r 35.000 average 220 WATER RESOURCES OF CALIFORNIA. TABLE la (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresfxjnding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Without flood control Esti- mated Year and month run-off Stage of Power draft Average power yield at reservoir through turbines in Waste .\verage n kilowatts dam at acre-feet Evapora- over (Load factor=0.75) site in acre-feet beginning of month in acre-feet tion in acre-feet spillway in acre-feet power head in feet Primary Secondary •Primarj- Secondary Total 1900 Jan. 1,299,000 2,698.000 232.000 247.000 578.000 405 97,400 103.500 200.900 Feb. 391.000 2.910.000 217.000 134.000 40.000 410 101,900 62.500 164.400 Mar. 912.000 2,940.000 245.000 242000 425.000 410 104.200 102.400 206.600 April 457,000 2.940,000 246.000 183.000 7,000 21.000 412 109.000 80.300 189,300 May 413,000 2.940.000 276,000 110.000 10.000 17.000 412 117,500 46.600 164,100 June 247,000 2.940.000 282,000 11.000 12,000 412 124,200 4.900 129 100 July 219.000 2,882.000 297.000 35,000 14,000 408 125.400 14.800 140,200 Aug. 208,000 2.755.000 303.000 43.000 13.000 402 126.700 17.900 144.600 Sept. 201.000 2.604.000 282.000 44.000 10.000 394 120.000 18.800 138.800 Oct. 508,000 2.469,000 278.000 121 000 7.000 .388 11S.400 49,200 162.600 Nov. 368.000 2,371.000 2fi-l.000 145.000 5,000 384 110.300 59,700 170.000 Dec. 697.000 2.325.000 271,000 222,000 384 109.400 89,000 198,400 Total or average 5,720,000 3,193,000 1,537,000 78,000 1,081,000 402 113,400 54,200 167,600 1901 Jan. 895.000 2.529.000 230,000 95.000 159.000 406 97.400 39.900 137,300 Feb. 1.304.000 2.940,000 218,000 223.000 863.000 408 101.900 104,200 206.100 Mar. 749.000 2.940.000 247,000 246.000 256.000 407 104.200 103,800 208.000 April 382,000 2.940.000 246,000 123.000 7,000 6.000 412 109.000 54,000 163.000 May 411,000 2,940.000 276,000 120.000 10,000 5,000 412 117,500 51,100 168.600 June 240,000 2.940.000 282,000 4.000 12,000 412 124.200 1,800 126,000 July 218,000 2.882.000 297,000 34.000 14.000 408 12.-,400 14,200 139.600 Aug. 206.000 2.755.000 303,000 41.000 13.000 402 126.700 17,100 143.800 Sept. 200.000 2,604.000 282.000 43.000 10.000 394 120.000 18,200 138.200 Oct. 21.5.000 2.460.000 278,000 28.000 7.000 388 113.400 11,400 124.800 Nov. 354.000 2.371.000 265,000 103.000 5,000 383 110.300 42.500 152.800 Dec. 550.000 2,352,000 272,000 252,000 383 109,400 100,600 210.000 Total or average 5,724.000 3,196.000 1.312.000 78,000 1,289.000 401 113,400 46,300 159,700 1902 Jan. 227,000 2.378,000 240.000 386 97,400 97,400 Feb. 2.782.000 2,365,000 224.000 153.000 1,830,000 392 101,900 69.300 171,200 Mar. 1.11.5.000 2,940,000 218.000 253.000 614,000 404 104.200 105.800 210,000 April 801,000 2.940.0OO 249.000 232.000 7,000 403,000 408 109.000 101.000 210.000 May 765.000 2.940.000 278.000 216,000 10,000 261,000 409 117.500 91.400 208,900 June 407.000 2.940.000 282.000 164,000 12,000 7,000 410 124.200 71.700 195,900 July 2,54,000 2.882,000 2ower head in feet of month in acre-feet Primary Secondary *Primary Secondary Total 1916 Jan. 1,166.000 2,472,000 232,000 78,000 388,000 403 97,400 32.700 130,100 Feb. 1,616,000 2,940,000 219,000 248,000 1,149.000 406 98.400 111.600 210,000 Mar. 1,215,000 2,940,000 248,000 252,000 715,000 404 104,200 10f,800 210,000 April 678.000 2.940,000 251,000 230,000 7,000 190,000 408 109,000 100,300 209,300 May 485,000 2,940,000 276,000 173,000 10,000 26,000 412 117,500 73,500 191,000 June 353.000 2,940,000 283.000 116,000 12,000 410 124.200 50,800 175.000 July 316.000 2,882,000 288,000 131,000 14,000 407 125,400 55,200 180,600 Aug. 244,000 2,755,000 304,000 78,000 13.000 400 126,700 32,500 159,200 Sept. 213,000 2,604,000 282,000 56,000 10,000 394 120,000 23,800 143,800 Oct. 236.000 2,469.000 278,000 49,000 7,000 388 113,400 19,900 133,300 Nov. 242,000 2,371,000 264,000 66,000 5,000 384 110,300 27,500 137,800 Dec. Tf»tj»l nr 363,000 2,278,000 273,000 111,000 380 109,400 44,500 153,900 1 utal UL average 7,127,000 3,208,000 1,588,000 78,000 2,468,000 400 113,000 56,300 169,000 1917 Jan. 312.000 2,257.000 242,000 382 97,400 97,400 Feb. 760,000 2.327.000 226,000 388 101.900 101,900 Mar. 459,000 2,861.000 243,000 126,000 11,000 412 104,200 53,500 157,700 April 906,000 2,940,000 248,000 231,000 7,000 420,000 410 109.000 101,000 210,000 May 580,000 2,940,000 276,000 210,000 10.000 84,000 411 1 17,500 89,000 206,500 June 329,000 2.940,000 283,000 92.000 12,000 410 124,200 40,300 164,500 July 238 onn 2 882 cm 297,000 51,000 14,000 402 125,400 22,700 148,100 Aug. 214;( -:-'•'«• 303,000 • 49.000 13,000 402 126,700 20,400 147,100 Sept. 185.UI'" _,■ "; ■ "'- 282,000 28,000 10,000 394 120,000 11,900 131.900 Oct. 200,0UU, j,l!j:<,u'j() 278,000 13,000 7,000 388 113,400 5,400 118.800 Nov. 224,000 2,371,000 264,000 48,000 5,000 384 110,300 20,000 130.300 Dec. 298,000 2,278,000 273,000 46,000 380 109,400 18,400 127,800 Total or average 4,705,000 3,215,000 897,000 78,000 515,000 397 113,400 32,000 145,400 1918 Jan. 249,000 2,257,000 243.000 380 97,400 97,400 Feb. 399,000 2,263,000 229,000 383 101,900 101,900 Mar. 772,000 2,433,000 251,000 8,000 6,000 398 104,200 3,400 107,600 April 556,000 2.940,000 247.000 208,000 7.000 94,000 411 109,000 91,100 200,100 May 314,000 2,940,000 276.000 28,000 10,000 412 117.500 12,000 129.500 Jane 232.000 2,940,000 282,000 12,000 412 124,200 124.200 July 200,000 2,878.000 297.000 12,000 14,000 408 125,400 5.100 130.500 Aug. 192,000 2,755.000 303.000 27,000 13,000 402 126,700 11.200 137,900 Sept. 180,000 2,604,000 282,000 29.000 10,000 394 120,000 12.400 132,400 Oct. 258,000 2,469,000 278,000 71.000 7,000 388 113,400 28.900 142.300 Nov. 246.000 2,.37 1,000 264,000 70,000 5,000 384 1 10,300 29.000 139,300 Dec. Total or 258,000 2.278,000 270,000 9,000 380 109.400 3.600 113,000 average 3,862.000 3.222,000 462.000 78.000 100.000 396 113,400 16.300 129,700 1919 Jan. 587,000 2 257.000 240,000 387 97,400 97.400 Feb. 1,163.000 2,604,000 219.000 150,000 458,000 404 101,900 69.300 171,200 Mar. 959.000 2,940,000 246.000 251,000 462,000 408 104,200 105.803 210,000 April 752,000 2,940.000 249.000 231.000 7.000 265,000 408 109,000 101.000 210,000 May 438,000 2,940,000 277,000 151.000 10,000 410 1 17,500 64,100 181.600 June 252,000 2,940,000 282,000 16.000 12,000 412 121,200 7,100 131,300 July 219,000 2,882,000 297,000 35.000 14.000 408 125,400 14.800 140,200 Aug. 199,000 2,755.000 303,000 34.000 13.000 402 126,700 U.200 140,900 Sept. 168.000 2,604,000 282,000 11.000 10,000 394 120,000 4,600 124.600 Oct. 203.000 2,469.000 278,000 16.000 7,000 388 113,400 6,500 1 19.900 Nov. 186,000 2,,371.0OO 264.000 10.000 5,000 384 110,300 4,200 114,500 Dec. Total or average 180,000 2,278,000 274,000 378 109,400 109,400 5,300,000 3,211,000 905,000 78,000 1,185,000 399 113.400 32.400 145,800 *Total primary power production in February of leap years taken the same as in other years. THE CONTROL OP FLOODS BY RESERVOIRS. 229 RESERVOIR ON SACRAMENTO RIVER. POWER GENERATION WITH INCIDENTAL IRRIGATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Daily Basis. mary, see Table 1, page 108.) Installed capacity of power plant 400,000 k.v a. P. F.=0.80 Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 12 5,000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Stage of Power draft Release through flood control outlets in acre-feet Average power deld Year and month reservoir at through turbines in acre-feet Evapora- Waste over Average in kilowatts (Load factor=( .75) beginning tion in acre-feet spillway in acre-feet power head in feet of month in acre-feet Primary Secondary *Primary Secondary Total 2.472,000 240,000 225,000 681,000 388 97,400 90,700 188,100 1916 Jan. 2,492,000 237,000 252,000 1,077,000 384 98,403 107,900 203,300 Feb. 2,512.000 252,000 236,000 391,030 396 104,230 97,030 201,200 Mar. 2,878,000 219,000 211,000 7,000 149,000 410 103,030 92,400 201.400 ■April 2,940,000 276,000 173,000 10,000 26,000 412 117,500 73.500 191,030 May 2,940,000 283,000 116,000 12,000 410 121.200 53.800 175,030 Jane 2,882,000 298,000 131,000 14,000 407 125.400 55.203 183,600 July 2,755,000 304.000 78,000 13,000 400 123.700 32,530 159,200 Aug. 2,604,000 282.000 53,000 10.000 394 123,003 23,830 14.3,830 Sept. 2,469,000 278.000 49,000 7.003 388 113.400 19,903 133,300 Oct. 2,371.000 264,003 66,000 5,003 384 110,303 27,500 137,890 Nov. 2,278,000 273,000 111,000 380 109,400 44,500 153,900 Dec. Total or average 3,233,000 1,704,000 78,000 2,149,000 175,000 396 113,000 59,500 172,500 2,257,000 242,000 382 97,400 97,400 1917 Jan. 2,327,000 226,000 26,000 178,000 387 101,900 11,600 113,500 Feb. 2,657,000 247,000 8,000 408 101.200 3,500 107,700 Mar. 2,861,000 249,000 196,000 7,000 375,003 408 103,000 85,600 194,603 April 2,940,000 276,000 210,000 10,000 84,000 411 117,533 89,030 206,503 May 2,940,000 283,000 92,000 12,000 410 124,200 40,300 164.503 June 2,882.000 297,000 51,000 14,000 408 125,400 22,703 148,100 July 2,755,000 303,000 49,000 13,030 402 126,703 23,400 147,100 -Aug. 2,604,000 282,000 28.030 10,000 391 120,000 11,900 131,930 S?pt. 2,469,000 278,000 13,000 7,000 388 113.400 5,400 118,800 Oct. 2,371,000 264,000 48,000 5,000 381 110,300 20,003 130,300 Nov. 2,278,000 273,000 46,000 380 103,400 18,403 127,800 Dec. Total or 3,220,000 770,000 78,000 178,003 459,000 397 113,400 27,400 * 140,800 average 2,257,000 243,000 380 97,400 97.400 1918 Jan. 2,263,000 220.000 383 101,903 101,900 Feb. 2,433,000 251,000 8.000 6,000 398 101,200 3,400 107,600 Mar. 2,940,000 247,000 208,030 7,000 94,000 411 109,000 91,100 200,100 .April 2,940,000 276,000 28,003 10,000 412 117,500 12,000 129,500 May 2,940.000 288.000 12.030 412 124,200 124,200 June 2,878.000 2,(7,000 12,000 14,000 408 125,400 5,100 130,500 July 2.755,000 303,000 27,000 13,000 402 125,700 11,200 137,900 Aug. 2,604,000 282,000 29,000 10.000 394 120,000 12,400 132,400 Sept. 2,469,000 278,000 71,000 7,000 388 113,400 28,900 142,300 Oct. 2,371.000 264.000 70,000 5,000 381 110.300 29.000 139.300 Nov. 2,278,000 270.000 9,000 380 109,400 3,600 113,000 Dec. Total or average 3,222,000 462,000 78,000 100,000 396 113,400 16,300 129,700 2,257,000 240,000 71,000 34,000 385 97,403 23.000 126,400 1919 Jan. 2,499,0 }0 226,000 222,000 671,000 387 101,900 99,600 201.500 Feb. 2,543,000 251,000 230,000 196,000 397 104,200 95,200 199,400 Mar. 2,825.000 249,000 224.030 7,000 18,000 139,000 409 109,000 97.600 206,600 .\pril 2,940,000 277,000 151,000 10,000 410 117,500 64,100 181,600 May 2,940,000 282,000 16,000 12,030 412 124,200 7,100 131.300 June 2,882,000 297,000 35,000 14,000 408 125,400 14,800 140,200 July 2,755,000 303.000 34,000 13.000 402 123,700 14,200 140.900 Aug. 2,604,000 232,000 11.000 10,000 394 120,000 4,600 124,600 Sept. 2,469,000 278,000 16,000 7,000 388 113,400 6,500 119,900 Oct. 2.371,000 264,000 10,000 5,000 381 110,300 4,200 114,500 Nov. 2,278,000 274,003 378 103,400 109,400 Dec. Total or average 3,223,000 1,020,000 78.000 919,000 139,000 396 113,400 36,000 149,400 230 WATER RESOURCES OF CALIFORNIA. TABLE la (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Without flood control Esti- mated run-off Year and month Stage of Power draft Average power yield at dam reservoir through turbines in Waste Average in kilowatt 3 at acre-feet Evapora- over (Load factor= 3.75) site in acre-feet beginning tion in acre-feet spillway in acre-feet power head in feet of month in acre-feet Primary Secondary ♦Primary Secondary Total 1920 Jan. 207,000 2,184,000 245,000 375 97,400 97.400 Feb. 176,000 2,146,000 233,000 372 98,400 98.400 Mar. 372,0001 2,089,000 263.000 374 104.200 104.200 April 493,000 2,198,000 262,000 6,000 383 109,000 109,000 May 286,000 2,423,000 288,000 9.000 388 117,500 117.500 June 216,000 2,412.000 296,000 10.000 386 124,200 124,200 July 192,000 2.32^,000 312,000 12,000 380 125,400 125.400 Aug. 176,000 2.190,000 321,000 11,000 372 126,700 126.700 Sept. 140,000] 2,034,000 301,000 8.000 363 120,000 120.000 Oct. 180,000 1,865.000 301,000 6,000 354 113.400 113,400 Nov. 896,000! 1,738,000 286,000 25,000 4,000 359 110.300 10.400 120.700 Dec. Total or average 1,121,000 2,319,000 265.000 244,000 397 109,400 100,600 210,000 4,455,000 3,373,000 269,000 66.000 376 113.000 9.400 122.400 1921 Jan. 1,492,000 2,931,000 232,000 270,000 981,000 404 97,400 112.600 210.000 Feb. 1.035,000 2,940,000 219,000 232.000 584,000 406 101.900 108.100 210,000 Mar. 982,000 2,940,000 246,000 252,000 484.000 408 101,200 105,800 210,000 April 559,000 2,940,000 247,000 227,000 7,000 78,000 410 109,000 99,000 208,000 May 493,000 2,940,000 276,000 195,000 10,000 12,000 411 117,500 83.200 200,700 June 316,000 2,940,000 283,000 79,000 12.000 410 124,200 34,600 158.800 July 220,000 2.882,000 297,000 36,000 14,000 408 125,400 15,200 140,600 Aug. 192,000 2,755,000 303,000 27,000 13,000 402 126,700 11.200 13V.90O Sept. 175,000 2,604,000 282,000 18,000 10,000 394 120,000 7,800 127,800 Oct. 196,000 2,469,000 277,000 7,000 389 113,400 113,400 Nov. 205,000 2,381.000 264,000 39,000 5,000 384 110,300 16,300 126,600 Dec. Total or average 390,000 2,278,000 273.000 72,000 381 109,400 28,900 138,300 6,255,000 3,199,000 1,447,000 78,000 2,139,000 400 113.400 51,600 165,000 1922 Jan. 300,000 2,323,000 240,000 387 97,400 97,400 Feb. 679,000 2,383,000 224,000 394 101,900 101,900 Mar. 567,000 2.8.38,000 244,000 142,000 79,000 411 104,200 60.100 164,300 April 604,000 2,940,000 248,000 214,000 7.000 135,000 410 109,000 93.600 202,600 May 577,000 2,940,000 276,000 209,000 10.000 82,000 411 117.500 88,300 205,800 June 317,000 2,940,000 283,000 80,000 12,000 410 121.200 35,000 159,200 July 203,000 2,882,000 297.000 19,000 14,000 408 125,400 7,900 133,300 Aug. 182,000 2,755,000 303.000 17,000 13,000 402 126,700 7,100 1.33,800 Sept. 161,000 2,604,000 282 JWO 4,000 10,000 394 120,000 1,700 121,700 Oct. 208,000 2,469,000 278,000 21,000 7,000 388 113.400 8.600 122,000 Nov. 244,000 2,371,000 264,000 68.000 5.000 384 110,300 28,300 138,600 Dec. Total or average 462.000 2,278,000 273.000 139,000 380 109,400 55,100 164.500 4,504.000 3,212.000 913,000 78.000 296,000 398 113.400 32,300 145,700 1923 Jan. 467,000 2.328,000 240,000 130,000 385 97.400 52,400 149,800 Feb. 297,000 2,425,000 225,000 390 101.900 101,900 Mar. 287,000 2,497.000 253.000 393 104.200 104.200 April 632,000 2..531,000 250,000 7,000 405 109,000 109,000 May 322,000 2,906,000 275,000 3,000 10.000 412 117,500 1,300 ! 118.800 June 236,000 2,940,000 282.000! 12.000 412 124.200 o; 124.200 July 184,000; 2.882,000 297,000 14,000 408 125,400 125,400 Aug. 16.5,000 2,755,000 303.000 13.000 402 126.700! 126.700 Sept. 157,000 2,604,000 282.000, 10.000 394 120.000, 120,000 Oct. 187,000 2,469,000 278,000 7.000 388 113.4001 113,400 Nov. 176.000 2.371.000, 264,000 i 5,000 384 110,300 110,300 Dec. Total or average 184.000 2,278,000 1 274,000 o; 379 109,400 109,400 3,294.000. 3,223,000 133,000' 78,000 1 398 1 13.400 j 4.600 118,000 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 231 RESERVOIR ON SACRAMENTO RIVER. POWER GENERATION WITH INCIDENTAL IRRIGATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Dailj" Basis. mary, see Table 1, page 108.) Installed capacity of power plant 400,000 k.v.a. P. F. =0.80 Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Blaff 125,000 sec.-f . Maximum reservoir space required 454,000 ac.-ft. Stage of Power draft Release through flood control outlets in acre-feet Average power yield Year and month reservoir at _ through turbines in acre-feet Evapora- Waste over Average in kilowatts (Load factor=0 .75) beginning tion in acre-feet spillway in acre-feet power head in feet of month in acre-feet Primary Secondary "Primary Secondary Total 2.184,000 245,000 375 97,400 97,400 1920 Jan. 2,146,000 233,000 372 98,400 98.400 Feb. 2,089,000 263,000 374 104,200 104,200 Mar. 2,198,000 262,000 6,000 383 109,000 109,000 April 2,423,000 288,000 9,000 388 117.500 117,500 May 2,412,000 296,000 10,000 386 121,200 124,200 June 2,322.000 312,000 12,000 380 125.400 125,400 July 2,190,000 321,000 11,000 372 126,700 126.700 Aug. 2,034,000 301,000 8,000 363 120,000 120,000 Sept. 1.865,000 301.000 6.000 354 113,400 113,400 Oct. 1,738,000 286,000 25,000 4,000 359 110.300 10,400 120,700 Nov. 2,319.000 266,000 245,000 202,000 395 109,400 100,600 210,000 Dec. Total or average 3,374,000 270,000 66,000 202,000 375 113,000 9.400 122,400 2,727,000 239.000 277,000 1,050,000 390 97,400 112,600 210,000 1921 Jan. 2,653,000 226,000 240.000 660,000 390 101,900 108,100 210,000 Feb. 2,562,000 252,000 244,000 226,000 336 104,200 100,900 205,100 Mar. 2,822,000 246,000 164,000 7,000 24,000 411 109,000 71,900 180,900 April 2,940,000 276,000 195,000 10,000 12,000 411 117,500 83,200 200,700 May 2,940,000 283,000 79,000 12.000 410 124,200 34,600 158,800 June 2,882,000 297.000 36000 14.000 408 125,400 1.5,200 140,600 July 2.755,000 303.000 27,000 13,000 402 126,700 11,200 137,900 Aug. 2,604.000 282,000 18,000 10.000 394 120,000 7,800 127,800 Sept. 2,469,000 277,000 7,000 389 113,400 113,400 Oct. 2,381,000 264,000 39.000 5,000 384 110,300 16.300 120,600 Nov. 2,278,000 273.000 72,000 381 109,400 28,900 138,300 Dec. Total or average 3,218,000 1,391,000 78.000 1,936,000 36,000 397 113,400 48,900 162,300 2,323,000 240,000 387 97,400 97,400 1922 Jan. 2,383,000 225,000 44.000 136,000 392 101,900 19,900 121,890 Feb. 2,657,000 246,000 17,000 21,000 407 104,200 7,300 111,500 Mar. 2,940,000 248.000 214,000 7,000 135,000 410 109,000 93,600 202,600 April 2,940.000 276.000 209,000 10,000 82,000 411 117,500 88,300 205,800 May 2,940,000 283,000 80.000 12,000 410 124,200 35,000 159,200 Jjne 2,882.000 297,000 19,000 14.000 408 125,400 7,900 133,300 July 2,755,000 303,000 17,000 13,000 402 126,700 7,100 133,800 Aug. 2.004.000 282,000 4,000 10,000 394 120,000 1,700 121,700 Sept. 2,469.000 278,000 21,090 7,000 388 113,400 8,600 122,000 Oct. 2,371,000 261,000 68,000 5,000 384 110,300 28,300 138,600 Nov. 2,278.000 273,000 139,000 380 109,400 55,100 164,500 Dec. Total or average 3,215,000 832,000 78,000 136,000 238,000 398 113,400 29,400 142,800 2,328.000 240.000 130,000 385 97,400 52,400 149,800 1923 Jan. 2,425,000 225.000 390 101,900 101,900 Feb. 2,497,000 253,000 393 104,200 104,200 Mar. 2,531,000 250,000 7,000 405 109,000 109,000 April 2,906.000 275.000 3,000 10,000 412 117,500 1,300 118,800 May 2,940,000 282,000 12,000 412 124.200 124,200 June 2,882,000 297,000 14.000 408 125,400 125.400 July 2,755,000 303,000 13,000 402 126.700 126,700 Aug. 2,604.000 282,000 10,000 394 120,000 120,000 Sept. 2,469,000 278,000 7,000 388 113,400 113.400 Oct. 2,371,000 264,000 5,000 384 110,300 110,300 Nov. 2,278,000 274,000 379 109.400 109,400 Dec. Total or average 3,223,000 133,000 78,000 398 113,400 4,600 118,000 232 WATER RESOURCES OF CALIFORNIA. TABLE la (Concluded). KENNETT WATER AND POWER YIELD. OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For correspH3nding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Without flood control Esti- mated 1 Year and month run-off Stage of Power draft 1 Average power yield at dam reservoir through turbines in Waste .Average 1 in Idlowatt s at acre-feet Evapora- over (Load factor=0.75) site in acre-feet beginning of month in acre-feet tion in acre-feet spillway in acre-feet power head in feet Primary Secondary 'Primary Sscondary Total 1924 Jan. 203,000 2,188,000 245,000 376 97,400 97,400 Feb. 332.000 2.146.000 231,000 378 98.400 98.400 Mar. 200,000; 2.247,000 260.000 379 104,200 104,200 April 176.000 2.187,000 266,000 6,000 374 109,000 109,000 May 155.000, 2.0;«.000 301.000 8000 367 117,500 117.500 June 141,0001 1.937.000 315.000 9.000 358 124.200 124,200 July 140.000 1.754,000 341,000 10.000 345 125.400 125,400 Aug. 140.000 1.543.000 360,000 8,000 330 126,700 126,700 Sept. 128.000 1.315,000 349,000 6,000 312 120.000 120.000 Oct. 178,000; 1,088.000 363,000 4.000 293 113.400 113,400 Nov. 317,0001 899,000 356.000 2,000 282 110,300 110.300 Dec. Totol or average 321,000 1 858,000 372,000 277 109,400 109,400 2,431,000 3,759.000 53,000 339 113,000 113.000 1925 Jan. 301.000 807,000 336,000 273 97,400 97,400 Feb. 1,769,000 772.000 264,000 326 101,900 101,900 Mar. 563,000 2,277,000 255,000 389 104.200 104,200 April 926,000 2,585,000 250.000 124.000 7,000 190,000 403 109,000 53,800 162.800 May 474.000 2,940,000 276,000 167,000 10,000 21,000 412 117,.5O0 70,800 188,300 June 276,000 2.940,000 282,000 40,000 12,000 411 124.200 17,500 141,700 July 173,000 2,882,000 297.000 14,000 408 125,400 125.400 Aug. 167,000 2.744,000 304,000 13.000 400 126,700 126,700 Sept. 163,000 2.594.000 282,000 10,000 394 120,000 120.000 Oct. 181.000 2,465,000 278.000 7,000 388 113,400 113,400 Nov. 192.000 2..%1,000 264,000 6,000 5.000 384 110,300 2,500 112,800 Dec. Total or average 235.000 2.278,000 273,000 380 100,400 109.400 5,420,000 3.361.000 337,000 78.000 211,000 381 113.400 12.100 125,500 Total for 30-year period. 1896-1926 188,012,000 97,101,000 37,953,000 2,300,000 50,674,000 Average (or 30-year period, 1896-1926 6,267,000 3,236,000 1,265,000 77,000 1,689,000 395.8 113,400 44,800 1 158,200 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 233 RESERVOIR ON SACRAMENTO RIVER. POWER GENERATION WITH INCIDENTAL IRRIGATION BY RESERVOIR OPERATING DIAGRAM. tioRS Carried out on a Daily Basis. mary, see Table 1, page 108.) Installed capacity of power plant 400,000 k.v.a. P. F. = 0.80 Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-f t. Maximum reservoir space required 451,000 ac.-ft. Stage of Power draft Release through flood control outletsin acre-feet Average power (field Year and reservoir at through turbines in acre-feet Evapora- Waste over Average in kilowatts (Load factor=:0.75) month beginning tion in spillway head in feet of month in acre-feet Primary Sscondar)' acre-feet in acre-ftet *Primary Secondary Total 1924 2,188,000 245,000 376 97,400 97,400 Jan. 2,146,000 231,000 378 98,400 98.400 Feb. 2,247,000 260.000 379 104,200 104,200 Mar, 2,187,000 266,000 6,000 374 109,000 109,000 April 2,091,000 301,000 8,000 367 117,500 117.500 May 1,937,000 315,000 9,000 358 124,200 124.200 June 1,754,000 341,000 10,000 345 125,400 125,400 July 1,543,000 360,000 8,000 330 126,700 126,700 Aug. 1.315,000 349,000 6,000 312 120,000 120,000 Sept. 1,088,000 363,000 4,000 293 113,400 113.400 Oct. 899,000 356,000 2,000 282 110,300 110,300 Nov. 858,000 372,000 277 109,400 100,400 Dec, Tntnl nr 3,759,000 53,000 339 113,000 113,000 1 Ultll KJl average 1925 807,000 336,000 273 97,400 97,400 Jan. 772,000 264,000 326 101,900 101.900 Feb. 2,277,000 255,000 389 104,200 104.200 Mar, 2,585,000 250.000 124.000 7,000 190.000 403 109.000 53.800 162,800 April 2,940.000 276.000 167.000 10,000 21,000 412 117,500 70,800 188,300 May 2,940,000 282.000 40,000 12.000 411 124,200 17,500 141,700 June 2,882,000 297,000 14.000 408 125.400 125,400 July 2.744,000 304.000 13.000 400 126,700 126,700 Aug, 2,594,000 282.000 10.000 394 120,000 120,000 Sept. 2,465,000 278.000 7.000 388 113,400 113,400 Oct. 2.361.000 264.000 6,000 5,000 384 110,300 2,500 112,800 Nov. 2,278,000 273,000 380 109,400 109,400 Dec. Total or 3,361,000 337,000 78,000 211,000 381 113,400 12,100 125,500 average Total for 30-year period, 97,481,000 37,094,000 2,300,000 40,414,000 10,739,000 1896-1926 Average for 30-year period. 3,249,000 1,236,000 77,000 1,347,000 358,000 393.8 113,400 43.400 156,800 1896-1926 15— 52411 2;i4 WATER RESOURCES OF CALIFORNIA. TABLE 2a. KENNETT RESER WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation Year and month run-off at dam site in Stage of reservoir at draft in acre-feet (no Evapora- Power draft through turbines Waste over Deficiency in irrigation supply Average power head Average power yield in acre-feet beginning deduction tion in spillway through kilowatts of for down- acre-feet in period of (Load month in acre-feet stream prior rights) in acre-feet acre-feet in a(!re-feet operation in feet factor= 1.00) 1896 Jan. 1,980,000 1,860,000 216,000 684,000 400 89,900 Feb. 474.000 2,940,000 439,000 35,000 411 199,400 Mar. 738.000 2,940,000 43,000 5:2,000 206,000 410 225,300 April 891,000 2,940,000 214,000 7,000 631,000 253.000 408 275,800 May 1,194,000 2,940,000 684,000 10,000 663,000 £00,000 406 280,000 June 536,000 2,940,000 855,000 12,000 648,000 339 280,000 July 313,000 2,609,000 941,000 13,000 704,000 376 280,000 Aug. 268,000 1,968,000 855,000 10.000 769,000 340 280.000 Sept. 2.58.000 1,371,000 513,000 6,000 513.000 312 176.100 Oct. 262.000 1,110,000 171,000 4,000 171,000 309 56,200 Nov. 472,000 1,197,000 3,000 Dec. 920.000 1,666,000 Total or average 8,306,000 4,276,000 65,000 5.286,000 1,678,000 375 178,400 1897 Jan. 577,000 2,586,000 141,000 82,000 411 59,800 Feb. 1,338,000 2,940,000 599,000 739,000 406 280.000 Mar. 737,000 2,940,000 43,000 601,000 136,000 409 254,600 April 858,000 2,940,000 214,000 7,000 63;),000 212,000 408 280,000 May 5.54,000 2,940,000 684,000 10,000 660,000 3,000 408 280,000 June 310.000 2,797,000 8.')5,000 11,000 663,000 389 280,000 July 275,000 2,241,000 911,000 12.000 741 000 354 280,000 Aug. 254,000 1,563,000 855,000 9,000 803.000 309 264.400 Sept. 247,000 953,000 513,000 5,000 513,000 272 152,400 Oct. 262,000 682,000 171,000 3.000 171,000 . 266 48,000 Nov. 274,000 770,000 2,000 Dec. 366,000 1,042,000 Total or average 6,052,000 4,276,000 59,000 5,531,000 1,172,000 359 180,800 1998 Jan. 257.000 1,408,000 Feb. 478.000 1,665,000 Mar. 380.000 2,143,000 43,000 43,000 385 17,300 April 274.000 2,480,000 214,000 7,000 211,000 395 91,000 May 300,(X)0 2,533,000 684.000 9,000 081,000 383 275,000 June 304,000 2,140,000 855,000 10,000 717,000 353 280,000 July 237,000 1,579,000 941.000 9,000 800,000 306 260.200 Aug. 225,000 866,000 855,000 6,000 091,000' 229 162.000 Sept. 198,000 230.000 426.000 2,000 87,000 Oct. 221,000 171,000 Nov. 217,000 50.000 Dec. 217,000 267.000 ToUl or average 3,308,000 4,189.000 43,000 3,149,000 87,000 342 91,200 1899 Jan. 605.000 484,000 Feb. 253,000 1.089,000 Mar. 900,000 1,342,000 43,000 43,000 347 15,900 April 456,000 2,199,000 214,000 6,030 214,000 384 89.300 May 330,000 2.435.000 684,000 9,000 684,000 379 272,400 June 302,000 2.072.000 K ■ ■. nnr 1 0,000 726,000 348 280,000 July 21(1.00(1 1,.'. 1(1.0(1(1 9,000 790,000 300 252,000 Aug. 221.(1(1(1 NOO (lOII 5,000 673,000 217 146,100 Sept. 197.0(10 Hi 1.01 10 1,000 153.000 Oct. 252.000 171,000 Nov. 645,000 81,000 Dec. ToUl or average 646,000 726.000 5.050.000 4,123,000 39,000 3,130,000 153,000 329 88.700 THE CONTROL OF FLOODS BY RESERVOIRS. VOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Daily Basis. mary, see Table 2, page 1 10.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. M xximum reservoir space required 454,000 ac.-ft. Irrigation Stage of reservoir draft in acre-feet Power draft through turbines Release through flood control outlets in acr e-feet Waste Deficiency Average power Average power Year and at beginning of Cno dednction for down- Evapora- tion in acre-feet over spillway in in irrigation supply head through period of yield in lulowatts (Load month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1896 1.860,000 246,000 1,085,000 382 99.100 Jan. 2.509,000 235,000 29,000 398 104.000 Feb. 2,719,000 43,000 321.000 34,000 162,000 407 134,900 Mar. 2,940,000 214,000 7.000 631,000 253,000 408 275.800 April 2.940,000 684,000 10,000 663.000 500,000 406 280,000 May 2,940,000 855,000 12,000 648.000 399 280,000 June 2,609,000 941,000 13,000 704,000 376 280,000 July 1,968.000 855.000 10,000 769.000 340 280,000 Aug. 1,371,000 513,000 6,000 513,000 312 176,100 Sept. 1,110,000 171,000 4,000 171,000 309 56,200 Oct. 1,197,000 3,000 Nov. 1,666,000 Dec. Total or average 4,276,000 65,000 4,901,000 1,148,000 915,000 373 164,000 1897 2,586,000 477,000 178,000 392 195,700 Jan. 2,508,000 618,000 698,000 385 276,000 Feb. 2,530,000 43,000 416,000 40,000 3J8 171,600 Mar. 2.811,000 214,000 7,000 5.54,000 168.000 408 242,100 April 2,940,000 684.000 10,000 660.000 3,000 408 280,000 May 2.797,000 855.000 11,000 663,000 389 280,000 June 2,241,000 941.000 12,000 741,000 354 280,000 July 1,563,000 855,000 9,000 803,000 309 264,400 Aug. 953,000 513,000 5,000 513,000 272 152,400 Sept. 682,000 171.000 3,000 171,000 266 48,000 Oct. 770,000 2,000 Nov. 1,042,000 Dec. Total or average 4,276.000 59,000 5,616,000 916,000 171,000 358 181,900 1898 1,408,000 Jan. 1,665,000 Feb. 2,143,000 43,000 43,000 385 17,300 Mar. 2.480,000 214,000 7,000 214,000 395 91,000 April 2,533,000 084,000 9,000 684,000 383 275,000 May 2,140,000 855,000 10,000 717,000 353 280,000 June 1,579,000 941,000 9.000 800,000 306 260,200 July 866,000 855,000 6,000 691,000 229 162,000 Aug. 230,000 426,000 2,000 87,000 Sept. 171,000 Oct. 50,000 Nov. 267,000 Dec. Total or average 4,189,000 43,000 3,149,000 87,000 342 91,200 1899 484,000 Jan. 1,089,000 Feb. 1,342,000 43,000 43,000 347 15,900 Mar. 2,199,000 214,000 6,000 214,000 384 89,300 April 2,435,000 684,000 9,000 684,000 379 272,400 May 2,072,000 855,000 9,000 726,000 348 280,000 June 1,510,000 941,000 9,000 790,000 300 252,000 July 800,000 855,000 5,000 673.000 217 146,100 Aug. 164,000 360.000 1,000 153,000 Sept. 171,000 Oct. 81,000 Nov. 726,000 Dec. Total or average 4,123,000 39,000 3,130,000 153,000 329 88,700 236 WATER RESOURCES OF CALITORNIA. TABLE 2a (Continued!. KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation Year and month run-off at dam Stage of reservoir draft in acre-feet Power draft through turbines Waste Deficiency Average power .\verage power site in ■ at (no Evapora- over in irrigation supply head yield in acre-feet bsginning deduction tion in spillway through kilowatts of for down- acre-feet in period of (T,na(l month in acre-feet stream prior righls) in acre-feet acre-feet in acre-feet operation in feet factors 1.00) 1900 Jan. 1,299.000 1,372,000 Feb. 391.000 2,671,000 122,000 4ii 57.300 Mar. 912.000 2,940.000 43,000 585,000 327,000 409 247,400 April 457,000 2,940.000 214.000 7,000 450,000 412 197,800 May 413.000 2.940,000 684.000 10,000 666.000 404 280,000 June 247,000 2,659,000 855,000 11,000 675,000 380 280,000 July 219.000 2,010.000 941,000 11.000 769,000 339 280,000 Aug. 208.000 1,307,000 855,000 8,000 772,000 284 232.500 Sept. 201.000 652,000 513,000 4.000 513,000 230 124.400 Oct. 308,000 336,000 171,000 2,000 171,000 222 38,200 Nov. 368,000 471,000 2.000 Dec. Total or average 697,000 837,000 5.720,000 4,276.000 55,000 4.723,000 327,000 337 145,500 1901 Jan. 895,000 1,534.000 Feb. 1.304,000 2.429,000 195.000 598,000 400 89.700 Mar. 749,000 2,940.000 43,000 588,000 161,000 409 348,800 April 382,000 2.940,000 214,000 7,000 3/5,000 412 165,000 May 411,000 2.940,000 684.000 10,000 663,000 404 280.000 June 240,000 2,657,000 855.000 11,000 675.000 380 280,000 July 218,000 2,031,000 941,000 11,000 772.000 339 280,000 Aug. 206,000 1,297,000 855,000 . 8,000 769,000 283 230,900 Sept. 200,000 640,000 513,000 4.000 513,000 228 123.100 Oct. 215,000 323.000 171.000 2,000 171,000 211 35,900 Nov. 354.000 365,000 1,000 Dec. Total or 6 V --rage 550,000 718.000 5.724,000 4.276,000 54.000 4.721.000 759.000 336 144,900 1902 Jan. 227,000 1.268,000 Feb. 2,782,000 1,495.000 240.000 1,097,000 398 110,100 Mar. 1,115,000 2,940,000 43.000 648.000 467.000 407 273,700 April 891,000 2.940,000 214,000 7,000 634.000 250,000 408 277.200 May 765,000 2.940,000 684,000 10,000 660.000 105,000 409 280,000 June 407,000 2.906.0O0 855,000 12,000 654.000 397 280,000 July 254,000 2,446,000 941,000 13,000 719.000 366 280,000 Aug. 231.000 1,746.000 855,000 9.000 812.000 323 280,000 Sept. 184,000 1,116.000 513,000 5,000 513.000 285 160.600 Oct. 235,000 782,000 171,000 3.000 171,000 276 50,000 Nov. 829.000 843,000 2.000 Dec. Total or average 762,000 1,670,000 8.685,000 4.276.000 61.000 5,051.000 1,919,000 361 166,300 1903 Jan. l.ll.'i.OOO 2.432.000 151.000 454,000 401 63.000 Feb. 633.000 2.940.000 565,000 68.000 410 265,500 Mar. 1,339,000 2.940.000 43.000 660,000 679,000 408 280,000 April May 765,000 2,940,000 214,000 7.000 609,000 149.000 409 266,400 458.000 2.940,000 684,000 10.000 663.000 405 280,000 June 278,000 2.704,000 855,000 11000 672,000 a 384 280.000 July 231,000 2.116.000 941,000 11,000 760,000 345 280.000 Aug. 204.000 1,395,000 855,000 8,000 781,000 292 242.700 Sept. 174,000 736.000 513,000 4,000 513.000 241 131.700 Oct. 199,000 303.000 171,000 2,000 171.000 222 38.300 Nov. 924,000 419,000 1,000 Dec. Total or average 530,000 1.342.000 6.848,000 4,276,000 54,000 5.5*5,000 1.350,000 347 176.700 THE CONTROL OF FLOODS BY RESERVOIRS. 237 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM, tions CaFried out on Daily Basis. mary, see Table 2, page 110.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P. F. = 0.80. Coordinated with flood control by reservoir operating diagram Maximiim controlled flow at Red Bluff 125,000 seo.-ft. M iximum reservoir space r equired 454,000 ac.-ft. Irrigation Stage of reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior rights) Evapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Average power head through period of operation in feet Average power yield in kilowatts (Load factor^ 1.00) Year and mouth 1900 1,372,000 181,000 390 73,800 Jan. 2,490.000 276.000 26,000 394 125,100 Feb. 2,579.000 43,000 334,000 279,000 ■ 400 137,400 Mar. 2,878,000 214,000 7,000 388,000 412 170,600 April 2,940,000 684,000 10,000 666,000 404 280,000 May 2,659,000 855,000 11,000 675,000 380 280,000 June 2.040,000 941,000 11,000 769,000 339 280,000 July 1,307,000 855,000 8,000 772,000 284 232,500 Aug. 652,000 513,000 4,000 513.000 230 124,400 Sipt. 338,000 171,000 2,000 171,000 222 38,200 Oct. 471.000 2,000 Nov. 837.000 Dec. Total or average 4,276,000 55,000 4,745,000 305,000 342 145,300 1901 1,534,000 Jan. 2,429,000 481,000 711.000 386 214,700 Feb. 2,541,000 43,000 387,000 99,000 398 159,100 Mar. 2,804,000 214,000 7,000 239,000 411 105,000 April 2,940,000 684,000 10,000 663.000 404 280.000 May 2,657,000 855,000 11,000 675,000 380 280,000 June 2,031,000 941,000 11,000 772,000 33J 280,000 July 1,297,000 855,000 8,000 769,000 283 230,900 Aug. 640,000 513.000 4,000 513,000 228 123,100 Sept. 323,000 171,000 2,000 171,000 211 35,900 Oct. 365,000 1,000 Nov. 718,000 Dec. Total or average 4,276,000 54,000 4,670,000 810,000 337 142,000 1902 1,268,000 Jan. 1,495,000 339,000 1,372,000 379 149,600 Feb. 2,566,000 43,000 529,000 310,000 397 218,000 Mar. 2,842,000 214,000 7,000 552,000 231,000 409 241,500 April 2,940,000 684,000 10,000 660,000 105,000 409 280,000 May 2,906,000 855,000 12,000 654,000 397 280,000 June 2,446,000 941,000 13,000 719,000 366 280,000 July 1,746,000 855000 9,000 812,000 323 280,000 Aug. 1,116,000 513,000 5,000 513,000 285 160,600 Sept. 782,000 171,000 3,000 171,000 276 50,000 Oct. 843,000 2,000 Nov. 1,670,000 Dec. Total or average 4,276,000 61,000 4,949,000 1,682,000 339,000 3.59 161,600 1903 2,432,000 442,000 614,000 387 178,800 Jan. 2,489,000 527.000 47,000 38J 237,600 Feb. 2,.548,000 43,000 612,000 463,000 3J5 252,000 Mar. 2,812.000 214,000 7,000 581,000 25,000 24,000 409 253,900 April 2,940,000 684,000 10,000 663,000 405 280,000 May 2,704,000 85.;,000 11.000 672,000 381 280,000 June 2,116,000 941,000 11,000 760,000 345 280,000 July 1,395,000 855,000 8,000 781,000 292 242,700 Aug. 736,000 513,000 4,000 513,000 241 131,700 Sept. 393,000 171,000 2,000 171,000 222 38,300 Oct. 419,000 1,000 Nov. 1,342,000 Dec 4,276,000 54,000 5,722,000 1,149,000 24.000 345 181,000 Total or average 288 WATER RESOURCES OF CALIFORNIA. TABLE 2a (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yeaily sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation Year and run-off at dam Stage of reservoir draft in acre-feet Power draft through turbines Waste De6cienoy Average power Average power month site in at Tno Evapora- over HI head jield in acre-feet beginning deduction tion in spillway irrigation supply through kilowatts of for down- acre-feet in period of (Load month in acre-feet stream prior in acre-feel acre-feet in acre-feet operation in feet factor^ 1.00) rights) 1904 Jan. 473,000 1,872,000 Feb. 1.742,000 2,345,000 281,000 866,000 400 125,100 Mar. 2,877,000 2,940,000 43,000 670,000 2,207,000 400 280.000 April 1,467,000 2,940,000 214,000 7,000 645,000 81.5,000 402 280.000 May 914,000 2,940,000 684,000 10,000 660,000 220,000 407 280,000 June .505,000 2,940,000 855,000 12,000 648,000 400 280.000 July 377,000 2,578,000 941,000 13.000 704,000 376 280,000 Aug. 282.000 2,001,000 8.5f,000 10,000 763,000 342 280,000 Sept. 271,000 1,418,000 513,000 6,000 513.000 316 178.300 Oct. 491,000 1,170,000 171,000 4,000 171,000 322 58,600 Nov. 379,000 1,486,000 3,000 Dec. 600,000 1,862,000 Total or average 10,378,000 4,276,000 65,000 5,055,000 4,108,000 372 170,200 1905 Jan. 1,371,000 2,462,000 315,000 578.000 404 132,100 Feb. 1,027,000 2,940.000 596,000 431,000 407 278,300 Mar. 1,33.5,000 2,940,000 43,000 649,000 686,000 406 273,500 April 7.53,000 2,940,000 214.000 7,000 619,000 127,000 409 270,800 May 560,000 2,940,000 684,000 10,000 660,000 408 280,000 June 365,000 2.806,000 855,000 11,000 660,000 391 280.000 July 269,000 2,305,000 941,000 12,000 735,000 358 280.000 Aug. 236,000 1 621.000 8.55,000 9,000 809,000 313 270,200 Sept. 208,000 993,000 513,000 5,000 513,000 274 153,800 Oct. 221,000 683,000 171,000 3,000 171,000 264 47,600 Nov. 229,000 730,000 2,000 Dec. 249.000 957,000 Total or avei age 6,823,000 4,276,000 59,000 5,727,000 1,822,000 361 188,300 1906 Jan. 851,000 1,206.000 Feb. 872,000 2,057,000 ■0 Mar. 1,646,000 2,92'.>,000 43,000 f57,O0O 978,000 409 280,000 April 995,000 2,940,000 214,000 7.000 642,000 346,000 406 280,000 May 817.000 2,940,000 684,000 10,000 660,000 123,000 407 280,000 June 756,000 2,940,000 855,000 12,000 641,000 44,000 406 280,000 July 362,000 2,785,000 941,000 14,000 688,000 387 280.000 Aug. 280,000 2,192,000 855,000 11,000 741,000 354 280.000 (Sept. 247.000 1,606,000 513.000 7.000 513.000 329 186,000 Oct. 251,000 1,533,000 171,000 5 000 171.000 326 59,300 Nov. 256,000 1,408,000 3,000 Dec. 648,000 1,661,000 Total or average 7,981,000 4.276.000 60,000 4,713.000 1.491,000 378 161,500 1907 Jan. 936,000 2,309.000 140,000 165,000 407 59,100 Feb. 1.636,000 2,940,000 602,000 1.034,000 403 280,000 Mar. 2,115,000 2,940,000 43,000 ()66,000 1,449.000 403 280,000 April May 1,250,000 2,940,000 214,000 7,000 642,000 601.000 404 280,000 646,000 2,940.000 684.000 10,000 658,000 8,000 409 280,000 Juno 421,000 2,884,000 855.000 12,000 651,000 3J6 280,000 July 334,000 2,438.000 941,000 13,000 716,000 368 280,000 Aug. 291,000 1,818,000 85,5,000 10.000 790,000 331 280,000 Sept. 252.000 1,244,000 513,000 6,001) f 13,000 301 169,700 Oct. 261,000 977,000 171,000 4,000 171,000 296 53,900 Nov. 256,000 1,063,000 3,000 Dec. Total or average 479,000 1.316,000 8.877,000 4,'?76,000 65,000 5,552,000 3,257,000 369 186.200 THE CONTROL OF FLOODS BY RESERVOIRS. 239 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Daily Basis. mary, see Table 2, page 1 10.) Seasona irrigation yield (deficiency in supp y one year in en, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,033 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Irrigation Stage of reservoir draft in acre-feet Power draft through turbines Release through flood control outlets in acre-feet Waste Deficiency Average power Average power Year and at beginning of (no deduction for down- Evapora- tion in acre-feet over spillway in in irrigation supply head through period of yield in kilowatts (Load month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1904 1,872,000 Jan. 2,345,000 363,000 1,194,000 38i 155,300 Feb. 2,530,000 43,000 688,000 1,861.000 387 280,000 Mar. 2,858,000 214,000 7,000 642,000 115,000 621.000 405 280,000 April 2,940,000 684,000 10,000 660,000 220,000 407 280,000 May 2,940,000 855,000 12,000 648,000 400 280,000 June 2,578,000 941,000 13,000 704,000 376 280,000 July 2,001,000 855,000 10,000 763,000 342 280,000 Aug. 1,418,000 513,000 6,000 513,000 316 178,300 Sept. 1,170,000 171,000 4,000 171,000 322 58,600 Oct. 1,486,000 3,000 Nov. 1,862,000 Dec. Total or average 4,276,000 65,000 5,152,000 3,170,000 841,000 370 172,600 1905 2,462,000 545,000 656,000 390 222,700 Jan. 2,632,000 591,000 469,000 393 268,600 Feb. 2,599,000 43,000 606,000 407,000 398 250,900 Mar. 2,921.000 214,000 7,000 618,000 18,000 91,000 409 270,800 April 2,940,000 684,000 10.000 660,000 408 280,000 May 2,806,000 855,000 11,000 660,000 391 280,000 June 2,305,000 941,000 12,000 735,000 358 280,000 July 1,621,000 855,000 9,000 809,000 313 270,200 Aug. 993,000 513,000 5,000 513,000 274 153.800 Sapt. 683,000 171,000 3,000 171,000 264 47,600 Oct. 730,000 2,000 Nov. 957,000 Dec. Total or average 4,276,000 59,000 5,908,000 1,550,000 91,000 359 193,300 190S 1.206,000 Jan. 2,057,000 117,000 206,000 392 53,300 Feb. 2,606,000 43,000 627,000 790,000 394 257,900 Mar. 2,835,000 214,000 7,000 640,000 104,000 139,000 407 280,000 April 2,940,000 684,000 10,000 660,000 123,000 407 280,000 May 2,940,000 855,000 12,000 641,000 44,000 406 280,000 June 2,78f,000 941,000 14,000 688,000 387 280,000 July 2,192,000 855,000 11,000 741,000 354 280,000 Aug. 1,606,000 513,000 7,000 513,000 32C 186,000 Sept. 1,333,000 171,000 5,000 171,000 326 59,300 Oct. 1,408,000 3,000 Nov 1,661,000 Dec. Total or average 4,276,000 69,000 4,798,000 1,100.000 306,000 377 163,700 1907 2,S09,000 539,000 218,000 389 219,600 Jan. 2,488,000 626,000 968,000 384 280,000 Feb. 2,530,000 43,000 680,000 1,147,000 392 278,600 Mar. 2,818,000 214,000 7,000 642,000 135,000 344,000 404 280,000 April 2,940,000 684,000 10,000 6.58,000 8,000 409 280,000 May 2,884,000 855,000 12,000 6.54,000 3;)6 280,000 June 2,438,000 941,000 13,000 716,000 368 280,000 July 1,818,000 855,000 10,000 790,000 331 280,000 Aug. 1,244.000 513,000 6,000 513,000 301 169,700 Sept. 977,000 171,000 4,000 i; 1,000 296 53,000 Oct. 1,063,000 3,000 Nov. 1,316,000 Dec. Total or average 4,276,000 65.000 5,989,000 2,468,000 352,000 366 199,700 240 WATER RESOURCES OF CALIFORNIA. TABLE 2a (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Withcut flood control Irrigation run-off Stage of draft in Power draft through turbines Deficiency Average Average Year and at dam reseivoir acre-feet Waste power power month site in at (no Evapora- over in head yield in acre-feet beginning deduction tion in spillway irrigation supply through lalowatts of for down- acre-feet in period of (Load month in acre-feet stream prior rights) in acre-feet acre-feet in acre-feet operation infect factor=: 1.00) 1908 Jan. 904,000 1,795,000 Feb. 970,000 2,699,000 472,000 257,000 409 213,100 Mar. 669,000 2,940,000 43,000 624.000 45,000 410 264,300 April 527,000 2,940,000 214,000 7,000 520,000 411 227.900 May 492,000 2,940,000 684.000 10,000 663.000 406 280.000 June 340,000 2,738,000 855.000 11,000 666,000 387 280,000 July '260,000 2,212,000 941.000 12,000 744,000 352 280.000 Aug. 229,000 1,519,000 855,000 8,000 797,000 305 258,500 Sept. 205,000 885,000 513,000 5.000 513.000 262 146.000 Oct. 235,000 572,000 171,000 3,000 171,000 251 44,800 Nov. 257,000 633,000 2,000 Dec. 267,000 888,000 Total or average 5,355,000 4,276.000 58,000 5,170,000 302,000 353 166,000 1909 Jan. 3,260.000 1,155,000 282,000 1,193,000 397 117,100 Feb. 2,526,000 2,940.000 605,000 1,921,000 400 280.000 Mar. 977,000 2,940,000 43.000 666,000 311,000 404 280.000 April 756,000 2,940,000 214,000 7,000 636,000 113,000 409 280.000 May 581,000 2,940,000 684,000 10,000 659,000 5,000 408 280,000 June 410,000 2,822.000 855,000 11,000 657,000 393 280.000 July 308,000 2,366,000 941,000 12,000 725.000 363 280.000 Aug. 264,000 1,721,000 855,000 9,000 809.000 323 280.000 Sept. 246,000 1,121,000 513,000 5.000 513,000 289 163,100 Oct. 284,000 849,000 171,000 3,000 171.000 286 51,700 Nov. 538.000 959,000 2,000 Dec. Total or average 721,000 1,495,000 10,871,000 4,276,000 59,000 5.723,000 3.543.000 362 190,400 1910 Jan. 708,000 2.216.000 Feb. 847,000 2,924,000 551.000 280.000 409 257,400 Mar. 1,239,000 2,940,000 43,000 663.000 576.000 405 280,000 April 665,000 2,940,000 214,000 7,000 603.000 55.000 411 264,900 May 41S.000 2,940,000 684,000 10,000 663.000 405 280,000 June 282,000 2,661,000 855,000 11,000 675.000 381 280,000 July 254,000 2,077.000 941,000 11,000 763.000 344 280.000 Aug. 236,000 1,379,000 855,000 8,000 781.000 292 242.600 "Sept. 214.000 752,000 513,000 4,000 513.000 246 135.400 Oct. 231,000 449.000 171,000 2,000 171.000 234 41,000 Nov. 274.000 507.000 2,000 Dec. Total or avefage 436,000 779.000 5,801,000 4.276.000 £5,000 5.383.000 911.000 347 171,100 1911 Jan. 700,000 1.215,000 Feb. 848,000 1,915,000 Mar. 1.278,000 2,763.000 43,000 562,000 539,000 407 237,000 April May 962,000 2.940.000 214,000 7,000 639,000 316,000 408 280,000 671,000 2.940.000 684,000 10,000 657,000 13,000 410 280,000 June 431.000 2,904,000 855,000 12,000 654,000 397 280,000 July 287.000 2,468,000 941,000 13,000 716,000 368 280,000 Aug. 244.000 1,801,000 855,000 10.000 797,000 328 280,000 Sept 231,000 1,180,000 513.000 6,000 513,000 294 165,600 Oct. 246,000 892.000 171,000 3,000 171,000 288 52,300 Nov. 241,000 964.000 2,000 Dec. Total or average 244,000 1.203,000 6,383,000 4,276,000 63,000 4,709.000 868.000 362 155,500 THE CUK'T'ROu OF FLOODS BY RESERVOIRS. 241 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Dail> Basis. mary, see Table 2, page 1 10.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. =0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled f ow at Red Bluff 125,000 sec.-ft. Maximum reservoir space re quired 454,000 ac.-ft. Irrigation Stage of reservoir at beginning of draft in acre-feet (no deduction for down- Evapora- tion in acre-feet Power draft through turbines Release through flood control outlets in acre-feet Waste over spillway in Deficiency in irrigation supply Average power head through period of Average power yield in lulowatts (Load Year and month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1908 1,795,000 44,000 399 18,100 Jan. 2,655,000 536,000 537,000 388 232,200 Feb. 2,552,000 43,000 311,000 16,000 401 128,900 Mar. 2,894,000 214,000 7,000 474,000 411 207,800 April 2,940,000 684,000 10,000 663,000 406 280,000 May 2,738,000 855,000 11,000 666,000 387 280,000 Jane 2,212,000 941,000 12,000 744,000 352 280,000 July 1,519,000 855,000 8,000 797,000 305 258,500 Aug. 885,000 513,000 5,000 513,000 262 146,000 S^pt. 572,000 171,000 3,000 171,000 251 44,800 Oct. 633,000 2,000 Nov. 888,000 Dec. Total or 4,276,000 58,000 4,919,000 553,000 352 155,900 average 1909 1,155,000 321,000 1,588,000 381 128,600 Jan. 2,506,000 623,000 1,784,000 386 280,000 Feb. 2,625,000 43,000 543,000 150,000 401 225,800 Mar. 2,909,000 214,000 7,000 027,000 2,000 89,000 409 2/5,300 April 2,940,000 684,000 10,000 659,000 5,000 408 280,000 May 2,822,000 855,000 11,000 657,000 3i)3 280,000 June 2,366,000 941,000 12,000 725,000 363 280.000 July 1,721,000 855,000 9,000 809,000 323 280,000 Aug. 1,121,000 513.000 5,000 513,000 289 163,100 Sept. 849,000 171,000 3,000 ia,ooo 286 51,700 Oct. 959,000 2,000 Nov. 1,495,000 Dec. Total or 4,276,000 50,000 5,648,000 3,524,000 94,000 363 186,400 average 1910 2,216,000 154,000 126,000 393 63,200 Jan. 2,644,000 414,000 303,000 399 190,300 Feb. 2,774,000 43,000 632,000 279,000 162,000 406 205, ZOO Mar. 2,940,000 214,000 7,000 603,000 55,000 411 264,900 April 2,940,000 684,000 10,000 663,000 405 280,000 May 2,661,000 855,000 11,000 075,000 381 280,000 June 2,077,000 941,000 11,000 763,000 344 280,000 July 1,379,000 855,000 8,000 781,000 292 212.600 Aug. 752,000 513,000 4,000 513,000 240 135,400 Sept. 449,000 171,000 2,000 171,000 234 41,000 Oct. 507,000 2,000 Nov. 779,000 Dec. Total or 4,276,000 55,000 5,369.000 708,000 217,000 317 170,100 average 1911 1,215,000 Jan. 1,915,000 167,000 5,000 394 75,600 Feb. 2,591,000 43,000 639,000 417.000 395 263,200 Mar. 2,813,000 214,000 7,000 638,000 59,000 131,000 407 278,300 April 2,940,000 684,000 10,000 657,000 13,000 410 280,000 May 2,904,000 855,000 12.000 654,000 397 280,000 June 2,468,000 941,000 13,000 716,000 368 280,000 July 1,801,000 855,000 10,000 797,000 328 280,000 Aug. 1,180,000 513,000 b,000 513,000 294 165,600 Sept. 892,000 171,000 3,000 171,000 288 52,300 Oct. 964,000 2,000 Nov. 1,203,000 Dec. Total or 4,276,000 63,000 4,952,000 481.000 144,000 363 163,400 average ';>j.-> WATER RESOURCES OF CALIFORNIA. TABLE 2a fContinued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,9'10,000 acre-feet. Estimated Without flood control Irrigation run-off Stage of draft in Power draft through turbines Deficiency .\verage Average Year and at dam reservoir acre-feet Waste power power month site in at (no Evapora- over in irrigation supply head yield in acre-feet beginning of deduction for down- tion in acre-feet spillway in through period of kilowatts (Load month in acre-feet stream prior in aci e-fcet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1912 Jan. .517,000 1,447,000 Feb. 396,000 1,964,000 Mar. 635,000 2,360,000 43,000 55,000 402 23.000 April 487,000 2,940,000 214,000 7,000 455,000 25.000 411 199,900 May 714,000 2,940,000 684,000 10.000 659,000 58,000 408 280.000 .lune 405.000 2,902,000 855.000 12.000 654,000 396 280.000 July 274.000 2,440,000 941,000 13.000 719,000 366 280.000 Aug. 238,000 1,760,000 855,000 9.000 806.000 325 280,000 Sept. 242,000 1,134,000 513,000 5,000 513,000 290 163,600 Oct. 226,000 858.000 171,000 3,000 171,000 284 51,500 Nov. 432,000 910,000 2,000 Dec. Total or average 369,000 1,340,000 4,935,000 4,276,000 61,000 4,032,000 83,000 360 130,200 1913 Jan. 763,000 1,709,000 Feb. 387,000 2,472,000 Mar. 441,000 2.859,000 43,000 3.54,000 6,000 412 1.50.400 April 685,000 2,940,000 214,000 7.000 626,000 52.000 410 274,300 May 521,000 2,940,000 684,000 10,000 663,000 406 280,000 June 321,000 2,767,000 85.^000 11.000 666,000 388 280,000 July 263,000 2.222,000 941,000 12.000 744,000 352 280.000 Aug. 232,000 1,532,000 855,000 8,000 800,000 306 260.400 Sept. 190,000 901,000 513,000 5,000 513.000 263 14fi..50O Oct. 202,000 573,000 171,000 3,000 171,000 249 44..500 Nov. 316,000 601,000 2,000 Dec. Total or average 696,000 915,000 5.017,000 4,276,000 58,000 4,537,000 58,000 348 143,800 1914 Jan. 2,797,000 1,611,000 346.000 1,122,000 399 144,100 Feb. 1,359,000 2,940,000 592,000 767,000 406 275,700 Mar. 987,000 2,940,000 43,000 600,000 327,000 407 280,000 April 1,137.000 2,940,000 214,000 7,000 639,000 491.000 407 278,600 May 703,000 2,940,000 684,000 10,000 657,000 37.000 409 280.000 June 452.000 2.912,000 855,000 12.000 651,000 398 280,000 July 309,000 2,497,000 941,000 13,000 713,000 370 280,000 Aug. 248,000 1,8.52,000 855,000 10.000 787,000 332 280,000 Sept. 225.000 1,235,000 513,000 0,000 513,000 298 168.300 Oct. 269.000 941,000 171,000 4,000 171,000 294 53,400 Nov. 2.52,000 1,035,000 3,000 Dec. Total or average 347,000 1.284,000 4,276.000 9.085.000 65,000 5,729,000 2,744,000 370 192.800 1915 Jan. 895.000 1,631,000 Feb. 2,298.000 2,526,000 682,000 1,302,000 402 269.200 Mar. 1,264,000 2,940,000 43,000 666.000 598,000 404 280,000 April 1,159,000 2,940,000 214,000 7,000 642,000 510,000 406 280,000 May 1,2.W.00() 2,940.000 684,000 10,000 ti()2,00() 562,000 406 280,000 June 572.000 2,940,000 855.000 12.000 ()45,000 403 280.000 July 343,(H)0 2,645,000 941,000 14.000 701,000 379 280.000 Aug. 266.000 2.033,(X)O 8.55,000 10.000 75il,()00 344 280,000 Sopl. 215.000 1.4;}4,0OO 513.000 6,000 513,000 314 177,.500 Oct. 233,000 i.i.mooo 171,000 4.000 171.000 309 56,000 Nov. . 254,000 1,188,000 3.000 Dec. Total or average 699,000 1,439,000 374 9.-.64,0OO 4,276,000 66.000 5,341,000 2.972.000 181,100 THE CONTROL OF FLOODS BY RESERVOIKS. 243 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM. tions Carried out on a Daily Basis. mary, see Table 2, page 1 10.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power p ant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by res srvolr operating diagram Maximurr controlled flow at Red Bluff 125,000 sec.-ft. Maximum reservoir space required 451,000 ac.-ft. Irrigation Stage of reservoir draft in acre-feet Power draft through turbines Release through flood control Oiitletsin acre-feet Waste Deficiency Average power .\verage power Year and at I b3ginning of 'no deduction for down- Evapora- tion in acre-feet over spillway in in irrigation supply head through period of yield in lulowatts (Load month month in acre-feet stream prior in acre-feet acre-feet in acre-fe3t operation in feet facto:= 1.00) rights) 1912 1.447.000 Jan. 1.9M.000 Feb. 2,.360.000 43,000 55.000 402 23,000 Mar. 2.940,000 214,000 7,000 4.55,000 25,000 411 199.900 April 2,940.000 684,000 10,000 6^9,000 58,000 408 280.000 May 2.902.000 855,000 12,000 654,000 396 280,000 June 2,440,000 941,000 13,000 719,000 366 280,000 July 1,760,000 855,000 9,000 80fi,000 325 280,000 Aug. 1.134,000 513,000 5.000 513,000 290 163,600 Sspt. 8.58.000 171,000 3,000 171,000 284 51,500 Oct. 910.000 2,000 Nov. 1.340.000 Dec. Total or average 4,276,000 61,000 4,032,000 83,000 360 130,200 1913 1,709,000 Jan. 2,472,000 135,000 400 62,500 Feb. 2.724,000 43,000 215,000 10,000 410 91.500 Mar. 2,940,000 214,000 7,000 626.000 52,000 40D 274,300 .A.pril 2.940,000 684,000 10,000 663,000 406 280,000 May 2.767,000 8.55,000 11,000 666,000 388 280,000 June 2.222,000 941,000 12,000 744.000 352 280.000 July 1,.532,000 855,000 8,000 800,000 308 260.400 Aug. 901.000 513.000 5,000 .bl3,000 263 146.500 Sept. .573,000 171,000 3,000 171,000 249 44.500 Oct. 601,000 2,000 Nov. 915.000 Dec. Total or average 4,276,000 58,000 4,533,000 10.000 52,000 352 143,600 1914 1.611.000 416,000 1.213.000 394 171.100 Jan. 2,779.000 612,000 752.000 394 280,000 Feb. 2,774,000 43,000 614,000 249,000 401 255,800 Mar. 2,898,000 214,000 7,000 627,000 461,000 407 273.200 .\pril 2,940,000 684.000 10,000 657,000 37,000 409 280.000 May 2.912,000 855,000 12,000 651,000 338 280.000 June 2,497.000 941,000 13,000 713.000 370 280,000 July 1,852.000 855.000 10,000 787.000 332 280,000 Aug. 1.235,000 513,000 6,000 513,000 298 168.300 S3pt. 941,000 171,000 4,000 171,000 294 53,400 Oct. 1,035,000 3,000 Nov. 1,284,000 Dec. Total or average 4,276,000 65,000 5,761.000 2.214,000 498,000 369 192,900 1915 1,631,000 22,000 16,000 38S 9,000 Jan. 2,488,000 620,000 1,475,000 386 278,100 Feb. 2,691,000 43,000 655,000 373,000 399 271,900 Mar. 2,927,000 214,000 7,000 642,000 32,000 465,000 405 280,000 April 2,940.000 684,000 10,000 662,000 562,000 406 280,000 May 2,940.000 855,000 12,000 645,000 403 280,000 June 2,645,000 941,000 14,000 701,000 379 280,000 July 2,033,000 855,000 I 10,000 7.59,000 344 280,000 Aug. 1,434,000 513.000 0,000 51b,000 314 177,.500 Sept. 1,130,000 171,000 ' 4,000 171,000 309 56,000 Oct. 1,188,000 3,000 i Nov. 1.439.000 ' ! Dec. Total or average 4,276,000 66,000 5,390,000 1,896,000 1,027,000 372 181,900 244 WATER RESOURCES OF CALIFORNIA. TABLE 2a (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation Year and run-off at dam Stage of reservoir draft in acre-feet Power draft through turbines Waste Deficiency Average power Average power month site in acre-feet at beginning of (no deduction for down- Evapora- tion in acre-feet over spillway in in irrigation supply head through period of yield in kilowatts (Load month in acre-feet stream prior rights) in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) 1916 Jan. 1.166,000 2,138,000 171,000 193,000 406 72,000 Feb. 1,616.000 2,940,000 620.000 996,000 404 277.900 Mar. 1,21.5.000 2,940,000 43,000 663.000 552,000 406 280,000 April 678,000 2.940,000 214.000 7,000 614.000 57.000 409 269,200 May 485,000 2.940,000 684,000 10,000 662,000 406 280.000 June 353,000 2,731.000 855.000 11,000 666.000 387 280,000 July 316.000 2,218,000 941,000 12.000 741.000 354 280,000 Aug. 244.000 1.581,000 855.000 9,000 806.000 311 266,900 Sept. 213,000 961,000 513,000 5,000 513,000 271 151.800 Oct. 236,000 656,000 171,000 3,000 171,000 262 47,000 Nov. 242,000 718,000 2,000 Dec. 363,000 958,000 Total or average 7,127,000 4.276,000 59,000 5,627,000 1,798,000 358 183 300 1917 Jan. 312.000 1,321,000 Feb. 760.000 1,633,000 Mar. 459,000 2,393,000 43,000 43,000 400 17.900 April 906,000 2,809,000 214,000 7,000 537,000 231,000 408 234,400 May 580,000 2,940,000 684,000 10,000 6.'i9.000 5,000 409 280,000 June 329,000 2,821,000 8.:f,000 11,000 660,000 391 280.000 July 238.000 2,284,000 941,000 12.000 738.000 356 280,000 .^ug. 214.000 1,569.000 855,000 9,000 803.000 308 263.400 Sept. 185,000 919,000 513,000 5,000 513,000 265 147,600 Oct. 200.000 586,000 171,000 3,000 171,000 250 44,600 Nov. 224.000 612,000 2,000 Dec. 298,000 834,000 Total or average 4,705,000 4,276,000 59,000 4,124,000 236,000 348 129,700 1918 Jan. 249,000 1,132,000 Feb. 399,000 1,381,000 Mar. 772,000 1.780,000 43,000 43,000 372 16,900 April 556,000 2,509,000 214,000 7,000 214.000 403 92.500 May 314,000 2,844,000 684,000 10.000 673,000 399 280.000 June 232,000 2.464.000 855,000 11.000 690.000 369 280.000 July 200,000 1,830,000 941,000 10,000 806,000 324 280,000 Aug. 192,000 1,079,000 855,000 7,000 732,000 258 197,400 Sept. 186,000 409,000 513.000 3,000 Oct. 258,000 79.000 171,000 1,000 Nov. 246,000 165,000 1,000 Dec. Total or 258.000 410,000 average 3.862.000 4,276.000 50.000 3,158,000 354 96,400 1919 Jan. 587.000 668.000 n Feb. 1.163,000 1.255,000 (1 Mar. 959,000 2418,000 43.000 340,000 97,000 407 113.100 April May 752,000 2,940,000 214,000 7,000 627,000 118.000 410 274.300 438,000 2,940,000 684.000 10,000 666,000 404 280.000 June 252.000 2,684.000 855,000 ll.OOO 675,000 381 280.000 July 219.000 2,070,000 941,000 11,000 766.000 342 280.000 Aug. 199.000 1.337.000 855.000 8,000 775.000 286 235,500 Sept. 168,000 673.000 513,000 4.000 513,000 230 124,600 Oct. 203.000 324.000 171.000 2.000 171.009 210 35,600 Nov. 186.000 354,000 1,000 Dec. Total or 180.000 539,000 average 5.306,000 4,276.000 54,000 4,533,000 215,000 334 138,500 THE CONTROL OF FLOODS BY RESERVOIRS. 245 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM. tions Carried out on a Dailj' Basis. mary, see Table 2, page 110.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. :)oordlnated with flood control by res ervoir operating diagram Maximum controlled £ ow at Red Bluff 125.000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Irrigation Stage of reservoir at beginning of draft in acre-feet l^no deduction for down- Evapora- tion in acre-feet Power draft through turbines Release through flood control outlets in acre-feet Waste over spillway in Deficiency in irrigation supply Average power head through period of Average power j-ield in kilowatts (Load Year and month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1916 2,138.000 397.000 415,000 386 160,900 Jan. 2.492,000 646,000 920,000 384 278.500 Feb. 2,542,000 43,000 616,000 263,000 396 254,300 Mar. 2,878,000 214,000 7.000 572,000 37,000 410 251.100 April 2,940,000 684,000 10,000 662,000 406 280.000 May 2,731.000 8.55,000 11,000 666.000 387 280,000 June 2,218,000 941.000 12,000 741.000 354 280,000 July 1,581,000 855,000 9,000 806.000 311 268.900 Aug. 961,000 513,000 5,000 513.000 271 151,800 Sept. 656,000 171,000 3,000 171,000 262 47,000 Oct. 718,000 2,000 Nov. 9i8,000 Dec. Total or average 4,276,000 59,000 5,790,000 1,598,000 37,000 355 187,200 1917 1,321,000 Jan. 1,633,000 Feb. 2,393,000 43,000 43,000 400 17,900 Mar. 2,809,000 214,000 7,000 537,000 231,000 408 234,400 April 2,940,000 684,000 10,000 659.000 5,000 409 280,000 May 2,821,000 855,000 11,000 660,000 391 280,000 June 2,284,000 941,000 12.000 738,000 356 280.000 July 1,569,000 855,000 9,000 803.000 308 263,400 Aug. 919,000 513.000 5,000 51.3.000 265 147,600 Sept. 586,000 171,000 3,000 171,000 250 44,600 Oct. 012,000 2,000 Nov. 834,000 Dec. Total or average 4,276,000 59,000 4,124,000 236,000 318 129,700 1918 1,132,000 Jan. 1,381,000 Feb. 1,780,000 43,000 43,000 372 16,900 Mar. 2,509,000 214,000 7,000 214,000 403 92,500 .\pril 2,844,000 684,000 10.000 673,000 399 280,000 May 2,464,000 855,000 11.000 690,000 369 280,000 June 1,830,000 941.000 10,000 806,000 324 280,000 July 1,079,000 855,000 7,000 732,000 258 197,400 Aug. 409.000 513.000 3,000 S^pt. 79,000 171,000 1,000 Oct. 165,000 1,000 Nov. 410,000 D-c. Total or a/erage 4,276,000 50,000 3,138,000 354 96.400 1919 668,000 Jan. 1,255,000 Feb. 2.418,000 43,000 507,000 45,000 398 209.800 Mar. 2,825,000 214,000 7,000 592,000 3,000 35,000 403 258,600 April 2,940,000 684,000 10.000 666,000 404 280,000 May 2,684,000 855,000 11,000 675,000 381 280,000 June 2,070,000 941,000 11,000 766,000 342 280.000 July 1,337,000 8.55.000 8,000 775,000 286 235..500 Aug. 673,000 513.000 4,000 513,000 230 124,600 Sept. 324,000 171,000 2,000 171,000 210 35,600 Oct. 354,000 1,000 Nov. 539,000 Dec. Total or average 4,276,000 54,000 4,665,000 48,000 35,000 332 142,900 24G WATER RESOURCES OF CALIFORNIA. TABLE 2a (Continued). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation run-off Stage of draft in Power draft through turbines Deficiency Average Average Year and at dam reservoir acre-feet Waste power power month site in at (no Evapora- over in irrigation supply head yield in acre-feet beginning deduction tion in spillway through kilowatts of for down- acre-feet in period of (Load month in acre-feet stream prior rights) in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) 1920 Jan. 207.000 719,000 ■ Feb. 176,000 926,000 Mar. 372.000 1,102,000 43,000 43,000 318 14,500 .\pril 493.000 1,431,000 214,000 5,000 214,000 340 80.100 May 286.000 1,705,000 684,000 7,000 684,000 333 243.300 .Tune 216,000 1,300,000 855,000 7,000 747.000 285 233,300 July 192.000 654,000 841.000 5,000 291,000 100,000 231 69,100 Aug. 176,000 176,000 679,000 Sept. 140,000 140.000 373,000 Oct. 180.000 168,000 3,000 Nov. 896,000 12,000 Dec. Total or average 1,121,000 908,000 4,45.5,000 3,121,000 24,000 1,979,000 1,155,000 315 53,400 1921 Jan. 1,492,000 2,029.000 162,000 419,000 402 67.700 Feb. 1.035,000 2,940,000 602,000 433.000 404 280,000 Mar. 982,000 2,940,000 43,000 660,000 322,000 407 280,000 April 559,000 2,940,000 214,000 7,000 540,000 12,000 410 236,500 May 493.000 2,940,000 684,000 10,000 663,000 406 280.000 June 316,000 2,739,000 855,000 11,000 666,000 387 280,000 July 220,000 2,189,000 941,000 12,000 7,50,000 349 280,000 Aug. 192,000 1,456,000 855,000 8,000 787,000 298 249,200 Sept. 175,000 785,000 513,000 4,000 513,000 247 136,300 Oct. 196,000 443,000 171,000 2,000 171,000 229 40,100 Nov. 205,000 466,000 2,000 Dec. Total or average 390,000 669,000 6,255,000 4,276,000 56,000 5,514,000 1,186,000 350 176,800 19J2 Jan. 300,000 1,0.59,000 Feb. 679,000 1,359,000 Mar. 567,000 2,038,000 43,000 43,000 383 17.300 April 604,000 2,562.000 214.000 7,000 219,000 410 95.600 May 577,000 2,940,000 684,000 10.000 060,000 409 280,000 June 317,000 2.823,000 855.000 11,000 660,000 390 280,000 July 203,000 2,274,000 941,000 12,000 741.000 354 280,000 Aug. 182,000 1,524.000 855,000 8,000 794,000 302 255,400 Sept. 161,000 843,000 513.000 4,000 513,000 2^4 140,400 Oct. 208,000 487,000 171,000 2,000 171,000 237 41,800 Nov. 244,000 522,000 2,000 Dec. Total or average 462.000 764,000 4,504,000 4,276,000 56,000 3.801,000 342 116,700 1923 Jan. 467,000 1,226,000 Feb. 297,000 1,693,000 Mar. 287,000 1,990.000 43,000 43,000 375 16.900 April 632,000 2,234,000 214,000 6,000 214,000 393 90,700 May 322.000 2.M6,(X)0 684,000 10.000 681,000 389 278,600 June 236,000 2,274.000 855,000 10.000 708,000 360 280,000 July 184,000 1,645.000 941.000 10,000 803,000 303 264,300 Aug. 165,000 878.000 855,000 6,000 682,000 224 154,200 Sept. 157.000 182,000 338.000 1.000 175,000 Oct. 187,000 171,000 Nov. 176,000 16.000 Dec. Total or average 184,000 192,000 3,204,000 4,101,000 43,000 3,134,000 175,000 341 91,100 THE CONTROL OP FLOODS BY RESERVOIRS. 247 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM. tions Carried out on a Daily Basis. mary, see Table 2, page 110.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood conlrol by res srvoir operating diagram Maximum controllsd flow at Red Bluff 125, OOC sec.-ft. M aximum reservoir space required 454,000 ac.-ft. Irrigation Stage of reservoir draft in aere-feet Power draft through turbines Release through flood control outlets in acre-feet Waste Deficiency Average power Average power at no) Evapora- over in head yield in Year and bsginning of deduction for down- tion in acre-feet spillway in irrigation supply through period of kilowatts (Load month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1920 719,000 Jan. 926,000 Feb. 1,102,000 43,000 43,000 318 14,500 Mar, 1.431,000 214,000 5,000 214,000 340 80,100 April 1,705,000 684,000 7,000 684,000 333 243,300 May 1,300.000 855.000 7,000 747,000 285 233,300- June 654,000 841,000 5,000 291,000 100,000 231 69,100 July 176.000 679,000 Aug. 140.000 373,000 Sspt. 168,000 3,000 Oct. 12,000 Nov. 908,000 Dec. Total or average 3,121,000 24,000 1,979,000 1,155,000 315 53,400 1921 2.029,000 331,000 537,000 388 134,700 Jan. 2,653,000 618,000 508.000 ,389 280,000 Feb. 2,562,000 43,000 675,000 47,000 397 280,000 Mar. 2,822,000 214,000 7,000 4,34,000 411 190,600 Aoril 2,940,000 684.000 10,000 663,000 406 280,000 May 2,739,000 855,000 11.000 666.000 387 280,000 June 2,189,000 941.000 12,000 750,000 349 280,000 July 1,456,000 855,000 8,000 787 000 298 219,200 Aug. 785,000 513,000 4,000 513,000 247 136,300 S^pt. 443,000 171,000 2.000 171,000 229 40,100 Oct. 466.000 2,000 Nov. 669,000 Dec. Total or average 4,276,000 56,000 5,608,000 1,092,000 348 178,700 1922 1,059,000 Jan. 1,359,000 Feb. 2,038,000 43,000 43,000 383 17,300 Mar. 2,562,000 214,000 7,000 219,000 410 95,600 .April 2,940,000 684,000 10.000 660.000 403 280,000 May 2.823,000 855,000 11,000 660,000 390 280,000 June 2,274.000 941,000 12,000 741,000 354 280.000 July 1,524,000 855,000 8,000 794.000 302 2,55,400 Aug. 843,000 513,000 4.000 513,000 254 140,400 Sjpt. 487,000 171,000 2,000 171,000 237 41,800 Oct. 522.000 2,000 Nov. 764,000 Dec. Total or average 4,276,000 56,000 3.801,000 342 116,700 1923 1,226,000 Jan. 1,693.000 Feb. 1,990,000 43.000 43,000 37.5 16,900 Mar. 2,234,000 214,000 6,000 214,000 393 90,700 April 2,646,000 684,000 10,000 684,000 389 278,600 May 2.274,000 855,000 10,000 708.000 360 280.000 June 1,645.000 941.000 10,000 803,000 309 264,300 July 878,000 855.000 6,000 682,000 224 151.200 Aug. 182,000 338,000 1,000 175,000 S^pt. 171,000 Oct. 16,000 Nov. 192,000 DiC. Total or average 4,101,000 43,000 3,134,000 175,000 341 91,100 248 WATER RESOURCES OF CALIFORNIA TABLE 2a (Concluded). KENNETT WATER AND POWER YIELD, OPERATING PRIMARILY FOR BOTH WITH AND WITHOUT FLOOD CONTROL Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Estimated Without flood control Irrigation run-off Stage of draft in Power draft through turbines Deficiency .\verage Average Year and at dam reservoir acre-feet Waste power power month site in at (no Evapora- over lit irrigation supply head yield in acre-feet beginning of deduction for down- tion in acre-feet spillway in through period of kilowatts (Load month in acre-feet stream prior rights) in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) 1924 Jan. 203,000 376,000 Feb. 332,000 579,000 Mar. 200,000 911,000 43,000 43,000 295 13.400 April . 176,000 1,068,000 214,000 4,000 214,000 301 70,700 May 1.55.000 1,020,000 684,000 5,000 684,000 265 191,400 June 141,000 492,000 629,000 4,000 131,000 226.000 220 30,000 July 140.000 140,000 801.000 Aug. 140,000 140.000 715,000 Sept. 128,000 128.000 385.000 Oct. 178,000 158,000 13,000 Nov. 317,000 20,000 Dec. 321,000 337,000 Total or average 2,431,000 2,136,000 13,000 1,072,000 2,140,000 283 25,600 1925 Jan. 301,000 658,000 Feb. 1,769,000 959,000 Mar. 563,000 2,728,000 43.000 338,000 13,000 4ii 143,800 April 026,000 2,940,000 214.000 7,000 635,000 284,000 408 277,500 May 474,000 2,940,000 684,0(10 10,000 663,000 405 280,000 June 276.000 2,720,000 8.55.000 11,000 669.000 384 280,000 July 173,000 2,130,000 941.000 11.000 763.000 394 280,000 Aug. 167,000 1,351,000 855.000 8,000 772.000 286 234,100 Sept. 163,000 655,000 513.000 4,000 513,000 227 122,400 Oct. 181,000 301.000 171.000 2,000 Nov. 1!)2,000 309.000 1,000 Dec. 235.000 500,000 Total or average 5,420,000 4,276,000 54,000 4.353,000 297,000 352 135,500 Total for 30-year period. 1896-1926 188,012,000 124.570,000 1,641,000 i36,ioaooo 33,096.000 3,710,000 Average for 30-year period, 1896-1926 6,267,000 4,152,000 55,000 4,537,000 1,103,000 124,000 353.4 145.300 THE CONTROL OF FLOODS BY RESERVOIRS. 249 RESERVOIR ON SACRAMENTO RIVER. IRRIGATION WITH INCIDENTAL POWER GENERATION BY RESERVOIR OPERATING DIAGRAM, tions Carried out on a Daily Basis. mary, see Table 2, page 1 10.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,0OC S8C.-ft. M iximum reservoir space required 454,000 ac.-it. Irrigation Stage of reservoir at beginning of draft in acre-feet (no deduction for down- Evapora- tion in acre-feet Power draft tlirough turbines Release through flood control outlets in acre-feet Waste over spillway in Deficiency in irrigation supply Average power head through period of Average power yield in kilowatts (Load Year and month month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) rights) 1924 376,000 Jan. 579,000 Feb. 911,000 43,000 43,000 29.5 13,400 Mar. 1,068,000 214,000 4,000 214,000 301 70,700 April 1,026,000 684,000 5.000 684.000 265 191,400 May 492,000 629,000 4,000 131,000 226,000 220 30,000 June 140,000 801,000 July 140,000 715,000 Aug. 128,000 385,000 Sept. 158,000 13,000 Oct. 20,000 Nov. 337,000 Dec. Total or average 2,136,000 13,000 1,072,000 2,140.000 283 25,600 1925 658,000 Jan. 959,000 111,000 89,000 387 49,900 98,8(ro Feb. 2,528,000 43,000 239,000 36,000 401 Mar. 2,816,000 214,000 7,000 588,000 27,000 180,000 408 256,900 April 2,940,000 684,000 10,000 663,000 405 280,000 May .2,720,000 855,000 11,000 669,000 384 280,000 June 2,130,000 941,000 11,000 763,000 344 280,000 July 1,351,000 855,000 8,000 772,000 286 234,100 Aug. 655,000 513,000 4,000 513,000 227 122,400 Sept. 301,000 171,000 2,000 Oct. 309,000 1,000 Nov. 500,000 Dec. Total or average 4,276,000 54,000 4,318,000 152,000 180,000 352 133,900 Total for 30-year period, 124,570,000 1,641,000 136,982,000 26,574,000 5,642,000 3.710,000 1896-1926 Average for 30-year period. 4,152,000 55,000 4 566,000 886,000 188,000 124,000 352.9 145.60. 1896-1926 IG— 52411 250 WATER RESOURCES OF CALIFORNIA. TABLE 3a. KENNETT RESER COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dami 420 feet. Capacity of reservoir 2,940,000 acre-feet. Year and month Estimated run-off at dam site in acre-feet Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Stage of reservoir at beginning of month in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet 1896 Jan. Feb. Mar. April May .June July Aug. Sept. Oct. Nov. Dec. Total or average 1897 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or average 1898 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or average 1899 Jan. Feb. Mar. April May Juno July Aug. Sept. Oct. Nov. Dec. Total or average 1,980,000 474,000 738,000 891,000 1,194,000 536,000 313,000 268,000 258,000 262,000 472,000 920,000 1,306,000 .^77,000 1,338.000 737.000 858,000 .554,000 310,000 275,000 254,000 247,000 262,000 274,000 366,000 6,052,000 257,000 478,000 380,000 274,000 300,000 304,000 2o7,000 22.7.000 198,000 221,000 217,000 217,000 3,308,000 605,000 253,000 1100,000 456,000 33(),0()() 302, (H)0 240,(K)0 224,000 197,000 252 000 645,000 646.000 5,050,000 1,860,000 2,509,000 2,719,000 2,940,000 2,940,000 2,940,000 2,609,000 1,968,000 1,371,000 1,110,000 1,197,000 1,666,000 43,000 214,000 684,000 855.000 941.000 855,000 513,000 171,000 7,000 10.000 12,000 13,000 10,000 6,000 4,000 3,000 1,331,000 264,000 172,000 302,000 670,000 £00,000 2,586,000 2,508,000 2.530,000 2 811,000 2,940,000 2,797,000 2,241,000 1,. 563, 000 953,000 682,000 770,000 1,042,000 4,276,000 43,000 214,000 684,000 855,000 941.000 855,000 £13,000 171,000 65,000 7,000 10,000 11,000 12,000 9.000 5,000 3,000 2,000 1,767,000 655,000 l,3ie,000 413.000 29,000 1,472,000 479,000 3,000 1,408,000 1.665,000 2,143,000 2,480,000 2,533,000 2,140,000 1,579,000 866.000 230,000 50,000 267,000 484,000 1,089.000 1,342,000 2.199,000 2.435,000 2.072,000 1.510.000 800.000 164,000 81,000 726,000 4,276,000 43,000 214,000 684,000 855,000 941,000 855.000 426,000 171,000 4,189,000 43,000 214,000 084,000 855,000 941,000 855,000 360,000 171,000 4,123,000 59,000 7,000 9,000 10.000 9,000 6.000 2,000 43,000 6,000 9,000 9,000 9,000 5.000 1,000 39,000 2.413,000 482000 THE CONTROL OF FLOODS BY RESERVOIRS. 251 VOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 3, page 1 12.) Seasonal irrgation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at- Red Bluff 125,000 sec.-ft. Stage of reservoir at beginning of month in acre-feet Irrigation draft in acre-feet Cno deduction for down- stream prior rights) Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Year and month 1896 1,860,000 1,354,000 Jan. 2,486,000 474,000 Feb. 2,486,000 43,000 695,000 Mar. 2,486,000 214,000 7,000 137.000 79,000 April 2,940,000 684,000 10.000 500.000 May 2,940,000 855,000 12,000 June 2,609,000 941,000 13.000 July 1,968,000 855,000 10,000 Aug. 1,371,000 513,000 6,000 Sept. 1,110,000 171,000 4,000 Oct. 1,197,000 3,000 Nov. 1,666,000 100,000 Dec. Total or average 4,276,000 65,000 2,760,000 579.000 1897 2,488,000 577,000 Jan. i 2,486,000 1,338,000 Feb. ■ 2,486,000 43,000 694,000 Mar. B. 2,486,000 214,000 7,000 138,000 45.000 April ■ 2,940,000 684,000 10,000 3,000 May 1 2,797,000 855,000 11,000 June 2,241,000 941,000 12,000 July 1,563,000 855,000 9,000 Aug. 953,000 513,000 5,000 Sept. 682,000 171,000 3,000 Oct. 770,000 2,000 Nov. 1,042,000 Dec. Total or average 4,276,000 59,000 2,747.000 48,000 1898 1,408,000 Jan. 1,665,000 Feb. 2,143,000 43,000 Mar. : 2,180,000 214,000 7,000 5,000 April ■ 2,528,000 684,000 9,000 May T 2,135,000 855,000 10,000 June 1,574,000 941,000 9,000 July 861,000 855,000 6,000 Aug. 225,000 421,000 2,000 92,000 Sept. 1 171,000 Oct. ■ 50,000 Nov. ^ 267,000 Dec. Total or average 4.184,000 43,000 5.000 92,000 1899 484,000 Jan. 1,089,000 Feb. 1,342,000 43,000 Mar. 2,199,000 214,000 6,000 April 2,435.000 684,000 9,000 May 2,072,000 855,000 9,000 June 1,510,000 941,000 9,000 July 800,000 855,000 5,000 Aug. 164.000 360,000 1.000 153,000 Sept. 171,000 Oct. 81,000 Nov. 726,000 Dec. Total or average 4,123,000 39,000 153.000 252 WATER RESOURCES OP CALIFORNIA. TABLE 3a (Continued). KENNETT COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red flow at Red Bluff 125,000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Estimated Year and month run-off at Irrigation dam site in acre-feet Stage of reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet rights) 1908 Jan. 904,000 1,795,000 44.000 Feb. 970,000 2,655,000 1,073,000 Mar. 669,000 2,552,000 43.000 284,000 April 527,000 2,894,000 214.000 7,000 260,000 May 492,000 2,940,000 684.000 10,000 June 340,000 2,738,000 855,000 11,000 July 260,000 2,212,000 941,000 12,000 Aug. 229,000 1,519,000 855,000 8.000 Sept. 205,000 885,000 513,000 5.000 Oct. 235,000 572,000 171,000 3,000 Nov. 257,000 633,000 2,000 Dec. 267,000 888,000 Total or averagf 5,355,000 4,276,000 58,000 1,401.000 260,000 1909 Jan. 3,260,000 1,155,000 1.909.000 Feb. 2,526,000 2,506,000 2,407,000 Mar. 977,000 2,625,000 43,000 650,000 April 756,000 2,909,000 214,000 7,000 35,000 469,000 May 581,000 2,940,000 (iS 1,000 10.000 5,000 June 410,000 2,822,000 855,000 11.000 July 308,000 2,366,000 941,000 12.000 Aug. 264,000 1,721.000 855,000 9.000 Sept. 246,000 1,121,000 513,000 5.000 Oct. 284,000 849,000 171,000 3.000 Nov. 538,000 959,000 2.000 Dec. Total or average 721,000 1,405,000 10,871.000 4,276,000 59,000 5,001,000 474,000 1910 Jan. 708,000 2,216,000 280,000 Feb. 847,000 2,644.000 717,000 Mar. 1,239,000 2,774,000 43,000 580,000 441,000 April 665,000 2,940,000 214.00(1 7,000 444,000 May 415,000 2,940,000 (>8t,00(l 10,000 June 282,000 2,661,fK)0 855.000 11,000 July 2?4,000 2,077.000 941,000 11,000 Aug. 236,000 1,379,000 855,000 8,000 Sept. 214,000 752,000 513,000 4.000 Oct. 231.000 449,000 171,000 2.000 Nov. 274,000 .507,000 2.000 Dec. Total or average 436,000 779,000 5,801,000 4,276,000 55,000 1,586.000 885,000 1911 Jan. 700,000 1,215,000 Feb. 848,000 1.915,000 172,000 Mar. 1,278,000 2,-591,000 43,000 1.013.000 April May 962,000 2,813.000 214,000 7,000 172.000 442.000 671,000 2.940,000 684,000 10,000 13,000 June 431,000 2,00'l,000 855,000 12,000 July 287,000 2,468,000 941.000 13,000 Aug. 244,000 1.8(11.(1011 855,000 10,000 Sept. 231.000 1,180,000 513.000 6,000 Oct. 240,0(K) 892.(M)0 171,000 3.000 Nov. 241,000 964.000 2,000 Dec. 244,000 1.203.000 Total or average 6.383,000 4,276,000 63,000 1.357,000 455,000 THE CONTROL OF FLOODS BY RESERVOIRS. 257 RESERVOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 3, page 112.) Seasona irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet; Flood control, holding maximum reservoir space required (454,000 ac.-ff.) n reserve throughout ^ood season Maximum controlled flow at Red Bluff 125, OOC sec.-ft. Irrigation Stage of draft in Release Waste over spillway in acre-feet Deficiency Year and reservoir at beginning of month in acre-feet Tno deduction for down- Evaporation in acre-feet through flood control outlets in acre-feet in irrigation supply in acre-feet month acre-feet stream prior rights) 1908 1,795,000 213,000 Jan. 2,486,000 970,000 Feb. 2,486,000 43,000 626,000 Mar. 2,486,000 214,000 7,000 58,000 e April 2,734,000 684,000 10,000 May 2,532,000 855,000 11,000 June 2,006,000 941,000 11,000 July 1,314,000 855,000 8,000 Aug. 680,000 513,000 4,000 Sept. 368,000 171,000 2,000 Oct. 430,000 1,000 Nov. 686,000 Dec. Total or 4,276,000 54,000 1,867,000 average 1909 953,000 1,727,000 Jan. 2,486,000 2,526,000 Feb. 2,486,000 43,000 934,000 Mar. 2,486,000 214,000 7,000 144,000 April 2,877,000 684,000 10,000 May 2,764,000 855,000 11,000 June 2,308,000 941,000 12,000 July 1,663,000 855,000 9,000 Aug. 1,063,000 513,000 5,000 Sept. 791,000 171,000 3,000 Oct. 901,000 2,000 Nov. 1,437,000 Deo. Total or 4,276,000 59,000 5,331,000 average 1910 2,158,000 380,000 Jan. 2,485,000 847,000 Feb. 2,486,000 43,000 1,193,000 Mar. 2,486,000 214,000 7,000 133,000 April 2,797,000 684,000 10,000 May 2,518,000 855,000 11,000 June 1,934,000 941,000 11,000 July 1,236,000 855,000 7,000 Aug. 610,000 513,000 4,000 Sept. 307,000 171,000 2,000 Oct. 365,000 1,000 Nov. 638,000 Dec. Total or 4,276,000 53,000 2,.556,000 average 1911 1,074,000 Jan. 1,774.000 136,000 Feb. 2,486,000 43,000 1,235,000 Mar. 2,486,000 214,000 7,000 263,000 24,000 April 2,940,000 084,000 10,000 13,000 May 2,904,000 855,000 12,000 June 2,468,000 941,000 13,000 July 1,801,000 855,000 10,000 Aug. 1,180,000 513.000 6,000 Sept. 892,000 171,000 3,000 Oct. 964,000 2,000 Nov. 1,203,000 U c Dec. Total or 4,276,000 ■ 63,000 1,634,000 37,000 average 258 WATER RESOURCES OF CALIFORNIA. TABLE 3a ^Continued). KENNETT COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125 000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Estimated Year and month run-off at Irrigation dam site in acre-feet Stage of re8er\'oir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet . rights) 1912 Jan. £17,000 1,447,000 Feb. 396,000 1.964,000 Mar. 635,000 2.360.000 43,000 12.000 April 487,000 2.940.000 214,000 7,000 266,000 May 714 000 2,940.000 684,000 10,000 58,000 June 405.000 2,902,000 855.000 12.000 July 274.000 2,440.000 941.000 13,000 Aug. 238,000 1.760,000 855.000 9,000 Sept. 242,000 1.134,000 513.000 5.000 Oct. 226,000 8.58,000 171,000 3,000 Nov. 432,000 910,000 2.000 Dec. 369,000 1,340,000 Total or average 4,935,000 4,276,000 61,000 336,000 1913 Jan. 763,000 1,709,000 Feb. 387,000 2,472,000 135,000 Mar. 441,000 2,724,000 43,000 37,oeo 145,000 April 685,000 2,940,000 214,000 7.000 464,000 May 521,000 2,940,000 684,000 10,000 June 321,000 2.767,000 855,000 11,000 July 263,000 2.222,000 941.000 12,000 Aug. 232,000 1,532,000 855.000 8,000 Sept. 190,000 901,000 513,000 5 000 Oct. 202,000 573,000 171.000 3,000 Nov. 316,000 601,000 2,000 Dec. ToUl or average 696,000 915,000 5,017,000 4,276,000 58,000 172,000 609,000 1914 Jan. 2,797,000 1,611,000 1,629,000 Feb. 1,359,000 2,779,000 1,364,000 Mar. 987,000 2,774,000 43,000 820,000 April May 1,137,000 2.898,000 214.000 7,000 30,000 844,000 703,000 2,940,000 684,000 10.000 37.000 June 452,000 2.912,000 855,000 12,000 July 309,000 2,497,000 941,000 13,000 Aug. 248,000 1,852,000 855,000 10,000 Sept. 225,000 1,235,000 513,000 6,000 Oct. 269,000 941,000 171,000 4,000 Nov. 252,000 1,035,000 3,000 Dec. Total or average 347,000 1,284,000 9,085,000 4,276,000 65,000 3,843,000 881,000 1916 Jan. 895,000 1,631,000 38,000 Feb, 2,298,000 2.488.000 2,095,000 Mar. 1,264,000 2,691,000 43,000 985,000 April May 1,159,000 2,927,000 214,000 7.000 47,000 878.000 1,256,000 2,940.000 684.000 10.000 562,000 June 572.000 2,940,000 855,000 12.000 July 343,000 2,645,000 941,000 14.000 Aug. 266,000 2,033,000 855,000 10.000 Sept. 215,000 1,434,000 513,000 6.000 Oct. 233,000 1,130.000 171,000 4,000 Nov. 254,000 1,188,000 3,000 Dec. Total or 699,000 1,439,000 averagn 9,454.000 4,276,000 66,000 3,165,000 1,440,000 THE CONTROL OP FLOODS BY RESERVOIRS. 259 RESERVOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 3, page 112.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) n reserve throughout flood season Maximum controUed flow at Red Bluff 125,00C sec.-ft. Stage of reservoir at beginning of month in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Year and month 1912 1,447,000 Jan. 1,964,000 Feb. 2,360,000 43,000 466,000 Mar. 2,486,000 214,000 7,000 45,000 April 2,707,000 684,000 10,000 May 2,727,000 855,000 11,000 June 2,266,000 941,000 12,000 July 1,587,000 855,000 9,000 Aug. 961,000 513,000 5,000 Sept. 685,000 171,000 3,000 Oct. 737,000 2,000 Nov. 1,167,000 Dec. Total or average 4,273,000 59,000 511,000 1913 1,536,000 Jan. 2,299,000 200,000 Feb. 2,486,000 43,000 398,000 Mar. 2,486,000 214,000 7,000 136,000 April 2,814,000 684,000 10,000 May 2,641,000 855,000 11,000 June 2,096,000 941,000 11,000 July 1,407,000 855,000 8,000 Aug. 776,000 513,000 4,000 Sept. 449,000 171,000 2,000 Oct. 478,000 2,000 Nov. 792,000 Dec. Total or average 4,276,000 55,000 734,000 1914 1,488,000 1,799,000 ■ Jan. 2,486,000 1,359,000 Feb. 2,486,000 43,000 944,000 Mar. 2,486,000 214,000 7,000 235,000 227,000 April 2,940,000 684,000 10,000 37,000 May 2,912,000 855,000 12,000 June 2,497,000 941,000 13,000 July 1,852,000 855,000 10,000 Aug. 1,235,000 513.000 6,000 Sept. 941.000 171,000 4,P00 Oct. 1,035,000 3,000 Nov. 1,284,000 Dec. Total or average 4,276,000 65,000 4,337,000 264,000 1915 1,631,000 40,000 Jan. 2,486,000 2,298,000 Feb. 2,486,000 43,000 1,221,000 Mar. 2,486,000 214,000 7,000 335,000 149,000 April 2.940,000 684,000 10,000 562,000 May 2,940,000 855,000 12,000 June 2,645,000 941,000 14,000 July 2,033,000 855.000 10,000 Aug. 1,434,000 513,000 6,000 Sept. 1,130,000 171,000 4,000 Oct. 1,188,000 3,000 Nov. 1,439,000 1 " Dec. Total or average 4,276,000 66,000 3,894,000 711,000 260 WATER RESOURCES OF CALIFORNIA. TABLE 3a (Continued). KENNETT COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Estimated Maximum reservoir sjiace required 454,000 ac.-ft. Year and month run-off at Irrigation dam site in acre-feet Stage of reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet rights) 1916 Jan. 1.166,000 2,138.000 812,000 Feb. 1.616.000 2,492,000 1 566.000 Mar. 1,21.1.000 2.,542,000 43,000 836,000 April 678,000 2.878.000 214,000 7.000 9,000 386,000 May 485.000 2,940,000 684,000 10.000 June 353.000 2.731,000 855,000 11,000 July 316,000 2.218,000 941,000 12,000 Aug. 244.000 1,. 581,000 855,000 9.000 Sept. 21.3,000 901,000 513.000 5,000 Oct. 236,000 656,000 171,000 3,000 Nov. 242,000 718.000 2.000 Dec. Total or average 363,000 958,000 7,127,000 4,276,000 59.000 3,223,000 386.000 1917 Jan. 312.000 1,321,000 Feb. 760.000 1,633,000 Mar. 459,000 2,393,000 43,000 April 906,000 2,809,000 214,000 7,000 5.54,000 May SSO.OOO 2.940,000 684,000 10,000 5.000 June 329,000 2,821,000 855,000 11,000 July 238,000 2,284,000 941,000 12,000 Aug. 214,000 1,569,000 855.000 9.000 Sept. 18.^000 919,000 513.000 5,000 Oct. 200,000 586,000 171,000 3,000 Nov. 224,000 012,000 2,000 Pec. Total or average 298,000 834,000 4,705,000 4,276,000 59,000 559,000 1918 Jan. ■ 249,000 1,132,000 Feb. 399,000 1,381,000 Mar. 772,000 1,780,000 43,000 April 556,000 2,,509,O00 214,000 7,000 May 314,000 2.844,000 684,000 10,000 June 232,000 2,464,000 8,^5,000 11.000 July 200,000 1,8.30,000 941,000 lO.OOO Aug. 192,000 1,079,000 855,000 7,000 Sfipt. 186.000 409,000 513.000 3,000 Oct. 258,000 79,000 171,000 1,000 Nov. 246.000 165,000 1,000 Dec. Total or average 258,000 410,000 3,862,000 4.276,000 50,000 1919 Jan. 587,000 068,000 Feb. 1.163,000 1,2.55,000 I) Mar. 959,000 2.418,000 43,000 5011.000 April May 752,000 2,825,000 214,000 7.000 82,000 334.000 438,000 2,940.000 084,000 10.000 June 2.52,000 2.084,000 855,000 11,000 July 219,000 2,070,000 941,000 1!,000 Aug. 199,000 1,337,000 855,000 8,000 Sept. 168,000 673,000 51.3.000 4,000 Oct. 203.000 .324,000 171,000 2,000 Nov. 186,000 354,000 1.000 Dec. Total or average 180.000 539,000 5,306.000 4,276.000 54,000 591,000 334,000 THE CONTROL OP FLOODS BY RESERVOIRS. 261 RESERVOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 3, page 1 12.) Seasona irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Irrigation draft in Release Waste over spillway in acre-feet Deficiency Year and month reservoir at beginning of month in acre-feet acre-feet fno deduction for down- stream prior Evaporation in acre-feet through flood controloutlets in acre-feet in irrigation supply in acre-feet rights) 1918 2,138,000 818.000 Jan. 2,486,000 1,616,000 Feb. 2,486,000 43,000 1,172,000 Mar. 2,486,000 214.000 7,000 129,000 April 2,814,000 684,000 10,000 May 2,605,000 855,000 11,000 June 2,092,000 941,000 11,000 July 1,456,000 855.000 8,000 Aug. 837,000 513,000 4.000 Sept. 533,000 171,000 2.000 Oct. 596,000 2,000 Nov. 836,000 Dec. Total or average 4,276,000 55,000 3.735,000 1917 1,199,000 Jan. 1,511,000 Feb. 2,271,000 43,000 201,000 Mar. 2,486,000 214,000 7,000 122,000 109,000 April 2,940,000 681,000 10,000 5,000 May 2 821,000 855,000 11,000 June 2.284,000 941,000 12,000 July 1,569,000 855,000 9,000 Aug. 919,000 513,000 5,000 Sept. 586,000 171,000 3,000 Oct. 612.000 2,000 Nov. 834.000 Dec. Total or average 4,276,000 59,000 323,000 114,000 1918 1,132,000 Jan. 1,381,000 Feb. 1,780,000 43,000 23,000 Mar. 2,486,000 214,000 7,000 87,000 April 2,734,000 684,000 10,000 May 2.354,000 855,000 10,000 June 1,721.000 941,000 10,000 July 970.000 855,000 6,000 Aug. 301.000 485,000 2,000 28,000 Sept. 171,000 Oct. 87,000 Nov. 333.000 Dec. Total or average 4,248,000 45,000 110,000 28,000 1919 591,000 Jan. 1,178,000 Feb. 2,341.000 43,000 771,000 Mar. 2,486,000 214,000 7,000 177.000 April 2.840,000 684,000 10,000 May 2,.58'1,000 855,000 11,000 June 1,970,000 941,000 11,000 July 1,237,000 855,000 7,000 Aug. 574,000 513,000 3,000 Sept. 226,000 171,000 1,000 Oct. 257,000 1,000 Nov. 442.000 Dec. Total or average 4,276,000 51,000 948,000 262 WATER RESOURCES OF CALIFORNIA. TABLE 3a (Continued). KENNETT COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125 000 sec.-ft. Maximum reservoir space required 454,000 ac.-ft. Estimated run-off at Year and month Irrigation dam site in acre-feet Stage of reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet rights) 1920 Jan. 207.000 719,000 Feb. 176.000 926,000 Mar. 372,000 1,102,000 43,000 April 493,000 1,431,000 214,000 5,000 May 286,000 1,705,000 684,000 7,000 June 216,000 1,300,000 855,000 7,000 July 192.000 654,000 841,000 5,000 100.000 Aug. 176.000 176,000 679.000 Sept. 140.000 140,000 373,000 Oct. 180,000 168,000 3,000 Nov. 896,000 12,000 Dec. 1,121,000 908,000 Total or average 4,455,000 3,121,000 24,000 1,155,000 1921 Jan. 1.492,000 2,029,000 868,000 Feb. 1,035,000 2,653,000 1.126,000 Mar. 982,000 2,562,000 43,000 679,000 April 559,000 2,822.000 214,000 7,000 9,000 211,000 May 493.000 2,940,000 684.000 10,000 June 316.000 2,739.000 855,000 11,000 Jjly 220,000 2,189,000 941,000 12,000 Aug. 192,000 1,456,000 8.55,000 8,000 Sept. 175,000 785,000 513,003 4,000 Oct. 196,000 443,000 171,000 2,000 Nov. 205,000 466,000 2,000 Doc. 390,000 669,000 Total or average 6.255,000 4,276,000 56,000 2,682,000 211,000 1922 Jan. 300,000 1,059,000 Feb. 679,000 1,359,000 Mar. 567,000 2,038,000 43,000 April 604,000 2,562.000 214,000 7,000 5,000 May 577,000 2.940,000 684,000 10,000 June 317,000 2,823,000 855,000 11,000 July 203,000 2,274,000 941,000 12.000 Aug. 182,000 1,. 524,000 855,000 8.000 Sept. 161,000 843,000 513,000 4,000 Oct. 208,000 487,000 171,000 2,000 Nov. 244,000 522,000 2,000 Dec. 462,000 764,000 Total or average 4,5(M,000 4.276,000 56,000 5,000 1923 Jan. 467,000 1,226,000 Feb. 297,000 1,693,000 Mar. 287,000 1,990.000 43.000 April 632,000 2,2.34,000 214,000 6,000 May 322,000 2,646,000 684,000 10,000 June 236,000 2.274,000 855.000 10,000 July 184,000 1,64^,000 941,000 10,000 Aug. 165,000 878,000 855,000 6,000 Sept. 157.000 182,000 338,000 1,000 175,000 Oct. 187,000 171.000 Nov. 176,000 16.000 Dec. 184.000 192.000 Total or average 3,294.000 4,101,000 43,000 175,000 TUE CONTROL OP FLOODS BY RESERVOIRS. 263 RESERVOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. many, see Table 3, page 112.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required (454,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of reservoir at beginning of month in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet Year and month 1920 622,000 Jan. • 829,000 Feb. 1,005,000 43,000 Mar. 1,334,000 214,000 4,000 April 1,609,000 684,000 7,000 May 1,204,000 855,000 6.000 June 559,000 746,000 5,000 195,000 July 176,000 679,000 Aug. 140,000 373,000 Sept. 168,000 3,000 Oct. 12,000 Nov. 908,000 Dec. Total or 3,026,000 22,000 1,250,000 average 1921 2,029,000 1,035,000 Jan. 2,486,000 1,035,000 Feb. 2,486,000 43,000 939,000 Mar. 2,486,000 214,000 7,000 110,000 April 2,714,000 684,000 10,000 May 2,513,000 855,000 11,000 June 1,963,000 941,000 11.000 July 1,231,000 855,000 7.000 Aug. 561.000 513,000 3,000 Sept. 220,000 171,000 1,000 Oct. 244,000 1,000 Nov. 448,000 Dec. Total or 4,276,000 51,000 3,119,000 average 1922 838,000 Jan. 1,138,000 Feb. 1,817,000 43,000 Mar. 2.341,000 214,000 6,000 2,000 April 2,723,000 681,000 10,000 May 2,606.000 855,000 11.000 June 2,057,000 941,000 11,000 July 1,308,000 855,000 8,000 Aug. 627,000 513,000 4,000 Sept. 271,000 171,000 2,000 Oct. 306,000 1,000 Nov. 549,000 Dec. Total or 4,276,000 53,000 2,000 average 1923 1,011,000 Jan. 1,478,000 Feb. 1.775,000 43,000 Mar. 2,019,000 214,000 0,000 .4pril 2,431,000 684,000 9,000 May 2,060,000 855,000 9,000 June 1,432,000 941,000 9,000 July 666,000 820,000 5,000 29,000 Aug. 157,000 356,000 Sept. 171,000 Oct. 16,000 Nov. 192,000 Dec. Total or average j 3,891,000 38,000 385,000 264 WATER RESOURCES OF CALIFORNIA. TABLE 3a (Concluded). KENNETT COMPARISON OF WATER YIELD FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow It Red Bluflt 125 000 sec.-f t. Maximum reservoir space required 454,000 ac.-ft. Estimated run-off at dam site in acre-feet Year and month Stage of reservoir at beginning of month in Irrigation draft in acre-feet (no deduction for down- Evaporation in acre-feet Release through flood controloutlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet stream prior acre-feet rights) 1924 Jan. 203,000 376,000 Feb. 332,000 579,000 Mar. 200,000 911,000 43,000 April 176.000 1,068,000 214,000 4,000 May 155,000 1,026,000 684,000 5,000 June 141,000 492,000 629,000 4,000 226,000 July 140.000 140,000 801.000 Aug. 140,000 140.000 715,000 Sept. 128,000 128,000 385,000 Oct. 178,000 158,000 13,000 Nov. 317,000 20,000 Dec. 321,000 337,000 Total or average 2,431,000 2,136,000 13,000 2,140,000 1925 Jan. 301,000 658,000 Feb. 1,769,000 959,000 200.000 Mar. 563,000 2,528,000 43,000 232,000 April 926,000 2,816.000 214,000 7,000 94,000 487,000 May 474.000 2,940,000 684,000 10,000 June 276.000 2.720,000 855,000 11.000 July 173,000 2,1.30,000 941,000 11,000 Aug. 167,000 1,.351.000 855,000 8,000 Sept. 163,000 655,000 513,000 4,000 Oct. 181,000 .301,000 171,000 2,000 Nov. 192,000 309,000 1,000 Dec. 235,000 £00,000 Total or average 5,420,000 4,276,000 54,000 526,000 487,000 Total for 30-year period. 1896-1926 188,012,000 124.570,000 1.641,000 49,509.000 13,417,000 3,710,000 Average for 30-year period, 1896-1926 6,267.000 4,152,000 55.000 1,650,000 447,000 124,000 THE CONTROL OK FLOODS BY KERERVOIRS. 265 RESERVOIR ON SACRAMENTO RIVER. OPERATING PRIMARILY FOR IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 3, page 1 12.) Seasonal irrigation yield (deficiency in supply one year in ten, no deduction for downstream prior rights) 4,276,000 acre-feet. Flood control, holding maximum reservoir space required f454,000 ac.-ft.) In reserve throughout f'ood season Maximum controlled flow at Red Bluff 125,000 see.-ft. Irrigation Year and Stage of reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior rights) Evaporation in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet month 1924 376,000 Jan. 579,000 Feb. 911,000 43,000 Mar. 1,068.000 214,000 4,000 April 1,026,000 684,000 5,000 May 492,000 629,000 4,000 226,000 June 140,000 801,000 July 140,000 715,000 Aug. 128,000 385,000 Sept. 158,000 13,000 Oct. 20,000 Nov. 337,000 Dec. Total or average 2,136,000 13,000 2,140,000 1925 658,000 Jan. 959,000 242,000 Feb. 2,486.000 43,000 520,000 Mar. 2,486,000 214,000 7,000 197,000 54.000 April 2,940,000 684,000 10,000 May 2,720,000 855,000 11,000 June 2,130,000 941,000 11,000 July 1,351,000 855,000 8,000 Aug. 655,000 513,000 4,000 Sept. 301,000 171,000 2,000 Oct. 309,000 1,000 Nov. 500,000 Dec. Total or average 4,276,000 54,000 959,000 54,000 Total for 30-year period. 124,224,000 1,582,000 60,257,000 3,074,000 4,056,000 1896-1926 Average for 30-year period, 4,141,000 53,000 2,009,000 102,000 135,000 1896-1926 17—52411 li6G WATEK RESOURCES OP ('ALIKORNIA. TABLE 4a. KENNETT RESER COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controllecl flow at Red Bluff 1 25,000 sec.-ft. Esti- Maximum reservoir space equired 454,000 ac- ft. mated run-off Year and at Stage of Power draft Release Average power yield month dam reservoir through turbines in through Waste Average power head in feet it kilowatts site at acre-feet Evapora- flood over (Load {actor=0.75) in acre-feet beginning tion in acre-feet control outlets spillway in of month in acre-feet Primary Second- ary in acre-feet acre-feet •Primary Second- ary Total 1896 Jan. 1,980,000 2.256,000 242,000 118,000 1,367,000 383 97,400 47.200 144,600 Feb. 474,000 2,509,000 231,000 51.000 50,000 396 98,400 22,300; 120.700 Mar. 738,000 2,651.000 247,000 49.000 153,000 405 104.200 20,4001 124,600 April 891,000 2,940,000 249,000 231,000 7,000 404,000 408 109,000 101,000 210,000 May 1,194,000 2,940,000 279,000 219,000 10,000 686,000 407 117,500 92,500| 210,000 June 536,000 2,940,000 283,000 196,000 12.000 80,000 410 124,200 85,800 1 210.000 July 313,000 2,905,000 298,000 151,000 14,000 407 125,400 63,700! 189,100 Aug. 268,000 2,755,000 304.000 102,000 13,000 400 126,700 42,500 169,200 Sept. 258,000 2,604,000 282,000[ 101,000 10,000 394 120,000 42.800, 162.800 Oct. 262,000 2,469.000 278,000 75,000 7,000 388 113,400 30,500 143,900 Nov. 472,000 2,371,000 264,000 161,000 5,000 385 110,300 66.800' 177,100 Dec. 920,000 2,413,000 268,000 247,000 223,000 390 109,400 100,600 210,000 Total or average 8,306,000 3,225.000 1,701,000 78,000 1.040.000 1,323,000 398 113,000 59.700 172.700 1897 Jan. 577,000 2,595,000 238,000 174,000 252,000 392 97.400 71,000 168.400 Feb. 1,338,000 2,508,000 228.000 242,000 846,000 385 101,900 108,100 210.000 Mar. 737,000 2,530,000 251,000 130,000 75,000 398 10*.200 53,200! 157,400 April 858,000 2,811,000 249,000 186,000 7,000 2,000 285,000 408 109,000 81,400 190,400 May 554,000 2,940.000 276,000 195,000 10,000 73,000 411 117,500 82,500 200,000 June 310,000 2,940,000 283,000 73,000 12,000 410 124,200 32,100i 1.56,300 July 275,000 2,882,000 298,000 90,000 14,000 407 125,400 37.900 1 163,300 Aug. 251,000 2,755,000 305,000 87,000 13,000 400 120.700 36,2001 162.900 Sept. 247,000 2,604,000 282,000 90,000 10,000 394 120.000 38,2001 158,200 Oct. 202,000 2,469,000 278,000 75,000 7,000 388 113,400 30,500 143,900 Nov. 274,000 2,371,000 265,000 97,000 5,000 382 110,300 40.300 150.600 Dec. Total or average 366.000 2,278,000 274,000 113,000 380 109,400 45,200 154.600 6.052,000 3,227.000 1,552,000 78,000 1,175,000 358,000 396 113.400 54.300 167.700 1898 Jan. 257,000 2,257,000 243.000 380 97.400 97.400 Feb. 478,000 2,271,000 220.000 388 101.900 101,900 Mar. 380,000 2.523,000 248,000 397 104.200 104.200 April May 274,000 2,655,000 253,000 7,000 400 109.000 109.000 300,000 2,669.000 281,000 10,000 401 117,500 117,500 June 30t,00f 2,678,000 287.000 11,000 ( 401 124,200 O' 124.200 July 237,000 2,084,000 301.000 c 14,000 400 125,400 O; 125,400 Aug. 225,000 2,606,000 307.000 c 12,000 396 126,700 126.700 S.pt. 198.000 2,512,000 284,000 c 9,000 390 120,000 Oi 120.000 Oct. 221,00C 2,417,000 279,000 7,000 386 113,400 0. 113,400 Nov. 217,00C 2,352,000 265.000 21,00C 5.000 383 110,300 8,800 119.100 Dec. 217,00C 2,278,000 274,000 380 109.400 109.400 Total or average 1 3,308,00C 3.248.000 21.00C 76,000 392 113.400 700 114.100 •Total prinuiry power production in February of leap years taken the same as in other years. THE CONTROL OF FI-OODS BY RESERVOIRS. 267 VOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 1 14.) Installed capacity of power plant 400,000 k.v.a. P.F. = 0.80. Flood control, folding maximum space required (454,000 ac -ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-lt. Stage of Power draft Release Average power yield Year and reservoir through turbines in through Waste Average in kilowatts month at acre -feet Evapora- flood over (Load factor= ).75) beginning tion in acre-feet control outlets spillway in power head in feet of mgnth in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1896 2,075,000 238,000 132,000 1,199.000 374 94,100 52,300 146,400 Jan. 2,486,000 226,000 182,000 06,000 390 95,100 79,300 174,400 Feb. 2,486,000 246,000 225,000 267,000 389 100,500 91,400 191,900 Mar. 2,486,000 245,000 115,000 7,000 70,000 398 105,300 49,000 154,300 April 2,940,000 268,000 228,000 10,000 688,000 408 113,300 96,700 210,000 May 2,940,000 274,000 205,000 12,000 80,000 411 119,700 90,300 210,000 June 2,905,000 287,000 212,000 14,000 407 121,100 88,900 210,000 July 2,705,000 296,000 198,000 13,000 395 122,300 81,600 203,900 Aug. 2,466,000 277,000 100,000 9,000 386 115,800 41,800 157,600 Sept. 2,338,000 272,000 75,000 7,000 382 109,500 30,100 139,600 Oct. 2,246,000 258,000 170,000 4,000 378 106,500 69,700 176,200 Nov. 2,286,000 202,000 260,000 198,000 383 105,600 104,400 210,000 Dec. Total or average 3,149,000 2,102,000 70,000 1,800,000 768,000 392 109,100 73,000 182,100 2,486,000 230,000 205,000 142,000 390 94,100 83,300 177,400 1897 Jan. 2,486,000 229,000 250,000 868,000 384 98,500 111,500 210,000 Feb. 2,486,000 247,000 264,000 226,000 Q 388 100,500 107,000 207,500 Mar. 2,486,000 245,000 156,000 7,000 70,000 398 105,300 60,500 171,800 April 2,866,000 267,000 228,000 10,000 410 113,300 96,700 210,000 May 2,915,000 275,000 208,000 12,000 406 119,700 90,300 210,000 June 2,730,000 291,000 90,000 14,000 400 121,100 37,600 158,700 July 2,610,000 298,000 88,000 12,000 394 122,300 36,200 158,500 Aug. 2,466,000 277,000 89,000 9,000 386 115,800 37,200 153,000 Sept. 2,338,000 272,000 75,000 7,000 382 109,500 30,100 139,600 Oct. 2,246,000 259,000 98,000 4,000 377 100,500 40,300 146,800 Nov. 2,159.000 268,000 182,000 372 105,000 71,500 177,100 Dec. Total or average 3,149.000 1,933,000 75,000 1,306,000 391 109,400 67,100 170,500 2,075,000 240,000 370 94,100 94,100 1898 Jan. 2,092,000 221,000 378 98,500 98,500 Feb 2,346,000 245,000 391 100,500 109,500 Mar. 2,481.000 247,000 7,000 394 105,300 105,300 April 2,501.000 276,000 9,000 394 113,300 113,300 May 2,516,000 282,000 11,000 394 119,700 119,700 June 2,527,000 296,900 13,000 392 121,100 121,100 July 2,45.),000 301,000 12,000 388 122,300 122,300 Aug. 2,367,000 278,000 9,000 384 115,800 115,800 Sept. 2.278.000 274,000 7,000 380 109,500 109,500 Oct. 2,218,000 259,000 13,000 4,000 376 106,500 5,300 111,800 Nov. 2,159,000 268,000 33,000 372 105,600 13,000 118,600 Dec. Total or average 3,190,000 46,000 72,000 384 109,400 1,500 110,900 268 WATER RESOURCES OF CALIFORNIA. TABLE 4a (Continued). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Compute (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operatin a diagram Maximum controlled flow at Red Bluff 125,000 scc.-ft. Esti- Maximum reservoir space required 454,000 ac. -ft. mated run-off Year and at Stage of Power draft Release Average power yield month dam reservoir through turbines in through Waste Average in kilowatts site a acre -feet Evapora- flood over (Load factor=0.75) in acre-feet beginning of tion in acre-feet control outlets spillway in power head in feet month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1899 Jan. 605,000 2,221,000 241,000 45,000 2,000 387 97,400 18,400! 115,800 Feb. 253,000 2,538,000 223,000 390 101,900 0' 101,900 Mar. 900,000 2.508,000 249,000 57,000 278,000 399 104,200 23,900! 128,100 April 456,000 2,884,000 246,000 140,000 7,000 7.000 412 109,000 61,500, 170,500 May 330,000 2,940,000 276,000 44,000 10,000 412 117.500 18,800 136,300 June 302,000 2,940,000 282,000 59,000 12,000 7,000 411 124,200 2,5,700 149,900 July 240,000 2,882,000 298,000 55,000 14,000 407 125,400 23,100 148,500 Aug. 224,000 2,755,000! 304,000 58,000 13,000 400 126,700 24,200 150,900 Sept. 197,000 2,604,000| 282,000 40,000 10,000 394 120,000 16,900 136,900 Oct. 252,000 2,469,000| 278,000 05,000 7,000 388 113.400 26,500 139,900 Nov. 645,000 2,371.000! 264,000 187,000 5,000 386 110,300 77,900 188,200 Dec. Total or average 646,000 2,560,000 266,000 244,000 108,000 390 109,400 100,600| 210,000 5,050,000 3,209,000 994,000 78,000 388,000 14,000 399 113,400 35,000 148,400 1900 Jan. i,2'jy,ooo 2,588,000 240,000 274,000 883,000 388 97,400 110,900 208,300 Feb. 391,000 2,490,000 224,000 49,000 29.000 394 101,900 22.000 123,900 Mar. 912,000 2,579,000 250,000 107,000 316,000 400 104,200 43,800 148,000 April 457,000 2,818,000 247,000 77,000 7,000 4,000 411 109,000 33,900 142,900 May 413,000 2,940,000 276,000 110,000 10,000 17,000 412 117,509 46.600 164,100 June 247,000 2,940,000 282,000 11,000 12,000 412 124.209 1,900 129,100 July 219,000 2,882,000 297,000 35,000 14,000 408 125.400 14,800 140,200 Aug. 208,000 2,755,000 303,000 43,000 13,000 402 126.700 17,900 144,600 Sept. 201,000 2,004.000 282,000 44,000 10,000 394 120.000 18,800 138,800 Oct. 308,000 2,469,000 278,000 121,000 7,000 388 113.400 49,200| 162,600 Nov. 368,000 2,371,000 264,000 145,000 5,000 384 110,300 59,700 170,000 Dec. 697,000 2,325,000 271,000 222,000 384 109,400 89,000l 198,400 Total or average 5,720,000 3,214,000 1,238,000 78,000 1,228,000 21,000 398 113.400 42,900 156,300 1901 Jan. 895,000 2,529,000 239.000 251,000 446,000 389 97.400 101,600 199.000 Feb. 1,304,000 2,488,000 227.000 223,000 801,000 386 101.900 99,400 201,300 Mar. 749,000 2,541,000 251.000 128,000 155,000 398 104,200 52,400 156,600 April 382,000 2,756,000 249.000 7,000 408 109,000 109,000 May 411,000 2,882,000 276,000 67,000 10,000 412 117,500 28,500 146,000 June 240,000 2,940,000 282,000 4,000 12,000 412 124,200 1,800 126.000 July 218,000 2,882,000 297.000 34,000 14,000 408 125,400 14.200 139,600 Aug. 206,00C 2,755,000 303,000 41.000 13,000 402 126,700 17,100 143,800 Sept. 200,000 2,604,000 282,000 43,000 10,000 394 120,000 18,200 138,200 Oct. 215,000 2,469,000 278,000 28,000 7,000 388 113,400 11,400 124,800 Nov. 354,000 2.371.000 265,000 103,000 5,000 383 1 10,300 42,500 152.800 Dec. Total or average 650,000 2.352,000 272,000 252,000 383 109,400 100,600 210.000 6,724,000 3,221,000 1,174,000 78,000 1.402,000 397 113,400 40.400 153,800 1902 Jan. 227.000 2,378.000 240.000 386 97.400 97.400 Feb. 2.782,000 2,366.000 230,000 176,000 2,175,000 381 101,900 77,100 179,000 Mar. 1.115.000 2,.566.000 251,000 183,000 409,000 398 104,200 75,300 179,500 April May 891,000 2,838,000 249.000 187,000 7,000 346,000 408 109,000 81, 5(H) 190,500 7(i5,(K)0 2,940,000 278,000 216,000 10,000 201,000 409 117,500 91,100 208,900 June 407,000 2,940,000 282,000 164,000 12,000 7,000 410 121,200 71,700 195,900 July 254.000 2,882,000 298,000 69.00C 14.000 406 125,400 29,000 154,400 Aug. 234.000 2,755,000 304.000 68.000 13.000 400 126,700 28,400 155,100 Sept. 184.000 2,604,000 282,000 27.000 10,000 394 120,000 11.400 131,400 Oct 235.000 2,469,000 278,000 48,000 7.000 388 113.400 19,500 132.900 Nov. 829.000 2,371,000 258,000 190,000 5.000 396 110.300 81,100 191.400 Deo. Total or average 762.000 2,747.000 264,000 241,000 352.000 400 109.400 100,600 210.000 8,685,000 3.214.000 1,569.000 78.000 2.936.000 614.000 398 113.400 56.300 168.700 'Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 269 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 114.) Installed capacity of power plant 400,000 k.v.a. P.P. =0.80. Flood control holding maximum space required (454,000 at .-ft.) In reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Power draft Release Average powtr yield Year and reservoir through turbines in through Waste Average in kilowatts month at acre-feet Evapora- flood over (Load factor= 0.75) beginning tion in acre-feet control outlets spillway in power head in feet of 1 month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1 1899 2,07.5,000 235.000 ° 380 94,100 9,, 100 Jan. 2,445,000 217,000 ! ■ 392 98,500 98,500 Feb. 2,481,000 247,000 1 212,000 i 436,000 388 100,500 85,900 186,400 Mar. 2,486,000 1 247,000 I 59,000 1 7,000 1 19,000 393 105,300 24,400 129,700 April 2,610,000 ' 272.000 9,000 399 113,300 113,bOO May 2,659,000 278.000 11,000 400 119,700 119,700 June 2,672,000 291,000 14,000 400 121,100 121,100 July 2,607,000 230.000 57.000 : 12,000 394 122.300 23,400 145,700 Aug. 2,466,000 276,000 40,000 9,000 388 115.800 16,800 132,600 Sept. 2,338,000 I 272.000 65,000 ' 7.000 382 109,500 26,100 ! 135,600 Oct. 2,246,000 258,000 197,000 4,000 379 106,500 80,700 187,200 Nov. 2,432,000 ! 260,000 257,000 86,000 38S 105,600 104,400 210,000 Dec. Total or average 3,149,000 887,000 73,000 541000 390 109,400 30,400 139,800 2,475,000 230,000 277,000 781,000 391 94,100 112,900 207,000 1900 Jan. 2,486,000 217,000 144,000 30,000 391 98,500 64,900 163,400 Feb. 2,486,030 247,000 257,000 408,000 388 100,500 104,200 204,700 Mar. 2,486,000 247,000 49,000 7,000 3,000 395 105,300 20,700 126,000 April 2,637,000 271,000 10,000 403 113,300 113,-300 May 2,769,000 275,000 11,000 404 119,700 119,700 June 2,730,000 290,000: 35,000 14,000 401 121,100 14,700 135,800 July 2,610,000 296,000 44,000 12,000 394 122.300 18,100 140,400 Aug. 2.466,000 276,000 44,000 9,000 388 115,800 18,500 134,300 Sept. 2,338,000 272,000 121,000 7,000 382 109,500 48,500 158,000 Oct. 2,246,000 259,000 151,000 4,000 377 106.500 61,900 168,400 Nov. 2,200,000 266,000 251,000 377 105,600 99,200 2(M,800 Dec. Total or average 3,146,000 1,373,000 74,000 1,222,000 391 109,400 47,100 156,500 2,380,000 232,000 287,000 270,000 387 94,100 115,900 210,000 1901 Jan. 2,486,000 220,000 239,000 845,000 385 98,500 106,800 205,300 Feb. 2,486,000 247,000 261,000 241000 388 100,500 106,000 206,500 Mar. 2,486,000 248,000 36,000 7,000 393 105,300 15.400 120,700 April 2,577,000 273,000 9,000 400 113,300 113,300 May 2,706,000 278,000 11,000 401 119,700 119,700 June 2,657,000 292,000 14,000 398 121.100 121.100 July 2,560,000 298,000 12,000 394 122,300 122,300 Aug. 2,465,000 269,000 49,000 9,000 388 115,800 20,600 136,400 Sept. 2,338,000 272,000 28,000 7,000 382 109,500 11,300 120,800 Oct. 2,246,000 259,000 106,000 4,000 377 106,500 43,300 149,800 Nov. 2,231,000 266,000 264,000 377 105,600 104,400 210,000 Dec. Total or average 3,154,000 1.270,000 73,000 1,356,000 389 109,400 43,400 152,800 2,251,000 236,000 379 94,100 91,100 1902 Jan. 2,242,000 223,000 183,000 2,132,000 378 98,500 79.800 178,300 Feb. 2,486,000 248,000 272,000 595,000 386 100,500 109.500 210,000 Mar. 2,486,000 245,0001 171,000 7,000 95,000 399 105,300 73,500 178,800 April 2,859,000 267,000 229,000 10,000 178,000 409 113,300 96,700 210,000 May 2,940,000 273,000 207,000 12,000 7,000 410 119,700 90.300 210,090 June 2,848,000 290,000 188,000 14,000 402 121,100 78,800 199,900 July 2,610,000 298,000 68,000 12,000 392 122,300 27,800 150,100 Aug. 2,466,000 276.000 27.000 9,000 387 115,800 11,400 127,200 Sept. 2,338,000 272,000 48.000 7,000 382 109,500 19,200 128,700 Oct. 2,246,000 255.000 202,000 4,000 146,000 385 106,500 84,.300; 190,809 Nov. 2,468,000 260,000 258,000 "i 226,000 388 105,600 101,4001 210,000 Dec. ToUl or average 3,143,0001 1,853,000 75,000 j 3, 194 ,000 1 185,000 391 109,400 64,500 173,900 270 WATER RESOURCES OF CALIFORXIA. TABLE 4a (Continued). KENNETT COMPARISON OF WATER AND POWER YIELD. OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Esti- Maximum reservcir space required 454,000 ac ft. mated run-off Year and at Stage of Power draft Release Average power yield month dam reservoir through turbines in through 'o"r^ Average in kilowatt s site at acre-feet Evapora- flood (Load factor=0.75) in acre-feet jeginning of tion in acre-feet control outlets spillway i J^T:^ in feet month in acre-feet Primary Second- ary in acre-feet acre-feet •Primary Second- ary Total 1903 Jan. 1,113,000 2,652,000 240,000 264.000 772,000 388 97.400 106,900 204,300 Feb. 633,000 2,489,000 226,000 222,000 126,000 390 101,900 100.100 202,000 Mar. 1,339,000 2,548,000 253,000 242,000 580,000 394 104,230 99,600 203,800 April 765,000 2,812,000 249,030 225,000 7.000 46,000 110,000 408 109,000 98,100 207,100 May 458,000 2,940,000 276,000 152,000 10,000 20,000 412 11 7, .500 64,700 182,200 .Tunc 278,000 2,940,000 282,000 42,000 12,000 412 124,200 18.300 142,500 .luly 231,000 2,882,000 297,000 47,000 14,000 408 125,400 19.800 145,200 Aug. 204,000 2,755,000 303,000 39,000 13,000 402 126,700 16,300 143,000 Sept. 174.000 2,604,000 282,000 17,0001 10,000 394 120,000 7,200 127,200 Oct. 199,000 2,469,000 278.000 12,000 7,000 388 113,400 4.800 118,200 Nov. 924,000 2,371,000 261,000 156,000 5.000 390 110,300 65.600 175,900 Dec. 530,000 2,873,000 263,000 229,000 310,000 400 109,400 95,300 204,700 Total or average 6,848.000 3,210,000 1.647,000 78.000 1.834.000 130.000 399 113,400 57.809 171,200 1904 Jan. 473,000 2,601,000 238,000 232,000 83,000 392 97,400 94.500 191.900 Feb. 1,742,000 2,521,000 236,000 165,000 1,332.000 386 98,400 70.500 168.900 Mar. 2,877,000 2,530,000 256,000 262,000 2.031.000 387 101,200 105,800 210,000 .\pril 1,467,000 2,858.000 250,000 234,000 7,000 146.000 748.000 405 109,000 101,000 210,000 May 914,000 2,940,800 279,009 220,000 10,000 405.000 406 117,500 92,500 210,000 June 505,000 2,940,000 283.000 196,000 12,000 48.000 410 124,200 85,800 210,000 July 377,000 2,906,000 298.000 201,000 14,000 406 125,400 84,600 210,000 Aug. 282,000 2,770,000 304,000 131,000 13,000 400 126,700 54,600 181,300 Sept. 271,000 2.604,000 282,000 114,000 10,000 393 120,000 48,300 168,300 Oct. 491,000 2.469.000 276.000 201,000 7,000 .391 113.400 81,900 195,300 Nov. 379,000 2.476,000 263,000 2U,000 5,000 386 110,300 99,700 210,000 Dec. 600,000 2.346.000 273.000 252,000 381 109.400 100,600 210.000 Total or average . 10,378,000 3,238.000 2,449,000 78,000 3,592,000 1,201,000 395 113.000 85.100 198.100 1905 .Ian. 1,371,000 2.421,000 238.000 179,000 743,000 391 97.400 72,600 170,000 Feb. 1,027,000 2,632,000 224.000 229,000 607,000 393 101,900 103.600 205,500 Mar. 1,335.000 2,599,000 251.000 238,000 524,000 398 104,200 98.400 202.600 April May 753,000 2,921,000 249.000 231,000 7,000 29,000 218,000 408 103,000 101.000 210,000 560.000 2,940,000 276,000 207,000 10.000 67,000 411 117,500 87,600 205,100 June 365,000 2,940.000 283,000 128,000 12.000 410 124,200 56,100 180,300 July 269,000 2,882,000 298,000 84,000 14,000 407 125,400 35.500 160,900 Aug. 236.000 2,755,000 304,000 70,000 13.000 400 126,700 29,200 155,900 Sept. 208.000 2,601,000 282,000 51,000 10.000 394 120,000 21,700 141,700 Oct. 221,000 2,469,000 278,000 34,000 7,000 388 113,400 13.800 127,200 Nov. 22D,000 2,371,000 264,000 53.000 5.000 b84 110,300 21.000 132,200 Dec. 249,000 2,278,000 270.000 380 109.400 109,400 Total or average 6,823,000 3.217.000 1.504.000 78.000 1,903.000 285.000 397 113.400 53.100 166,500 906 Jan. 851,000 2.2.57,000 239,000 52,000 109,000 390 97,400 21,600 119,000 Feb. 872,00(1 2.708.000 222.000! 141,000 611,000 398 101,000 63,700 16.5,600 Mar. l,t>ir),n()o s.tinii.odo: :>53,oi)(i 2tl.oo() 924.000 0' 394 104.200 98,900 203,100 April May !i'.l,i,(H)(l, 2. S:t 1.0(H); 249.(»()0i 2:i2,(K)0 7.(K)0: 136,000 2t)o,000; 408 109,000 101,000 210,000 817.(»')0; 2.il40.(HK) 278.000; 220.00(1 10.000 309,000 408 117,.500 92.500 210,000 June 756.(MK) 2,940,(H1(I, 284,000! 196,000 12.000 265,000 409 124.200 85,800 210,000 July 302.000 2,93',t,l)O0 297,000 201,000 14.000 408 12.5,400 84,600 210,000 Aug. 280.0(M) 2.78'.t,0(MI 304.000 148,000 13.000 400 126.700 61,700 188,400 Sept. 247.00(1 2.60t.0(H) 283.000 89,000 10,000 394 120.000 37,800 l,=7,8O0 Oct. 251,0(K) 2.469.{KK): 278.000| 64,000 7,000 388 113,400 26,100 139,500 Nov. 256,000 2.371,000 205,000 79,000 5,000 383 110,300 32.800 143,100 Dec. 648,000 2.278,000 272,000| 186,000 382 109,400 74,300 183,700 ToUl or average 7.981.000 3,224,000j 1.849.000 78,000 1.780.000 839,000 397 113,400 65.100 178,500 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 271 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 114.) Installed capacity of power plant 400,000 k.v.a. P.F. = 0.80. Flood control, liolding maximum space required (454,000 ac. -ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec .-ft. Stage of Power draft Release Average power yield reservoir through turbines in through Waste Average n kilowatts Year and at _ acre-feet Evapora- flood over (Load factor=fl .75) month beginning tion in acre-feet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet ♦Primary Second- ary Total 1903 2,486,000 231,000 222,000 660,000 387 94,100 89.500 183.600 Jan. 2,486.000 219,000 249,000 165,000 386 98,500 111, .500 210,000 Feb. 2,486,000 248,000 270,000 821,000 386 100,500 109,509 210,000 Mar. 2,486,000 246,000 99,000 7,000 151,000 396 105,300 41,900 147,200 April 2,748,000 270,000 145,000 10,000 (1 405 113,300 60,600 173,900 May 2,781,000 275,000 43,000 11,000 405 119,700 18,600 138,.300 June 2,730,000 290,000 47,000 14,000 401 121,100 19,600 140,700 July 2,610,000 296,000 40,000 12,000 394 122,300 16,500 1.38,800 Aug. 2,466,000 276,000 17,000 9,000 388 115,800 7,100 122,900 Sept. 2,338,000 272,000 12,000 7,000 382 109,500 4,800 114,300 Oct. 2,246,000 257,000 166,000 4,009 257,000 380 106,500 68,200 174,700 Nov. 2,486,000 260,000 257,000 35,000 389 105,600 104,400 210,000 Dec. Total or 3,140,000 1,567,000 74,000 2,089,000 392 109,400 54,100 163,500 average 2.464.000 230.000 202,000 19,000 390 94,100 82,300 176,400 1904 Jan. 2.486,000 228,000 209,000 1,305,000 384 95,100 89,400 184,500 Feb. 2.-186,000 252,000 276,000 2,349,000 378 100,500 109,500 210,000 Mar. 2,486,000 245,000 196,000 7,000 257,000 308,000 398 105,300 84,000 189,300 April 2.940,000 268,000 228,000 10,000 408,000 408 113,300 96,700 210,000 May 2,940,000 273,000 206,000 12,000 48,000 410 119,700 90,300 210,000 June 2,906,000 288,000 211,000 14,000 406 121,100 88,900 210,000 July 2,770,000 265,000 213,000 13,000 398 122,300 87,700 210,000 Aug. 2,531,000 276,000 178,000 10,000 388 115,800 74,600 190,400 Sept. 2,338,000 271,000 252,000 7,000 382 109,500 100,500 210,000 Oct. 2,299,000 260,000 249,000 4,000 376 106,500 101,500 208,000 Nov. 2.165,000 269,000 259,000 372 105,600 101,500 207,100 Dec. Total or average 3,155,000 2,679,000 77,000 3,930,000 764,000 391 109,100 92,300 201,400 2,237,000 234,000 158.000 730,000 384 94,100 63,600 157.700 1905 Jan. 2,486,000 219,000 251,000 557,000 386 98,500 111,500 210,000 Feb. 2,480,000 249,000 272,000 814,000 385 100,500 109,500 210,000 Mar. 2,486,000 246,000 107,000 7,000 128,000 396 105,300 45,600 150,900 April 2,751,000 270,000 210.000 10,000 406 113,300 88,200 201,500 May 2,821,000 275,000 170.000 11,000 404 119,700 73,800 193,500 June 2,730,000 231,000 84,000 14.000 400 121,100 34,900 156,000 July 2,610,000 298,000 70.000 12.000 394 122,300 28,800 151,100 Aug. 2,406,000 270.000 51,000 9.000 387 115,800 21,400 137,200 Sept. 2,338,000 272,000 34,000 7,000 382 109,500 13,700 123,200 Oct. 2,246,000 259,000 53,000 4,000 378 106,500 21,800 128,300 Nov. 2,159.000 268,000 65,000 372 105,600 25,500 131,100 Dec. Total or average 3,157,000 1,525,000 74,000 2,229,000 390 109,400 52,800 162,200 2,075,000 235.000 109,000 96,000 380 94,100 44,400 138,500 1906 Jan. 2,486,000 219,000 214,000 439,000 387 985,000 95,800 194,300 Feb. 2,486,000 248,000 273,000 1,101,000 384 100.500 109,500 210,000 Mar. 2,510,000 246,000 145,000 7,000 278,000 397 105.300 61,500 166,800 April 2,829,000 268,000 229,000 10,000 1 199,000 409 113,300 96,700 210,000 May 2,940,000 273,000 207,000 12.000 1 266,000 410 119,700 90,300 210,000 June 2,938,000 287,000 212.000 14,000 408 121,100 88,900 210,000 July 2,787,000 294.000 211.000 13,000 398 122,300 87,700 210,000 Aug. 2,549,000 276,000 172,000 10,000 388 115,800 72,200 188,000 Sept. 2.338,000 272.000 64.000 7,000 382 109,500 25,700 135,200 Oct. 2,246,000 259,000 80,000 4,000 378 106.500 32,900 139,400 Nov. 2,159,000 267,000 215,000 1 375 105.600 84.700 190,300 Dec. Total or average 3,144,000 2,131,000 77,000 1,914,000 465,000 391 109,400 74,100 183,500 272 WATER RESOURCES OF CALIFORNIA. TABLE 4a (Continued). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Esti- Max mum reservoir space required 454,000 ac -ft. mated run-off Year and at Stage of Powe draft Release .\verage power yield month dam reservoir through turbines in through Waste Average in kilowatts site at acre-feet Evapora- flood over (Load factor=0.75) in acre-feet beginning tion in acre-feet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet •Primary Second- ary Total 1907 Jan. 936,000 2,488,000 239,000 247,000 430,000 389 97,400 100,300 197,700 Feb. 1,636,000 2,488,000 229,000 243,000 1,122,000 384 101,900 108.100 210,000 Mar. 2,115,000 2,o30,000i 2.54,000 259.000 1,314,000 392 104,200 105,800 210,000 April 1,250,000 2.818.000 249.000 2.940.0001 278,000 234.000 7,000 178,000 460,000 406 103,000 101,000 210,000 May 646,000 219.000 10,000 139,000 408 117,500 92.500 210,000 June 421,000 2,940,000 282,000 179.000 12,000 6,000 410 124,200 78.200 202,400 July 334,000 2,882,000| 2.)8.000 149.000 14,000 406 12.5,400 62.600 188,090 Auc 2i)l,000 2.755,000: 304,000 125,000 13,000 400 126,700 52,000 178,700 Sept. 2.52,000 2,604,000 282.000 95,000 10,000 394 120,000 40,300 160,300 Oct. 261,000 2,469,000 278,000 74,000 7,000 388 113,400 30,100 143,500 Nov. 256,000 2,371,000 264.000 80,000 5,000 384 110,300 33,300 143.600 Dec. 479,000 2,278,000 273,000 138,000 380 103.400 55,100 164.500 Total or average 8,877,000 3,230,000 2,042,000 78,000 3,044,000 605,000 395 113,400 71,400 184,800 1908 Jan. 904,000 2,346,000 237,000 94,000 264,000 394 97,400 38,300 135,700 Feb. 970,000 2,655,000 234,000 210,000 629,000 388 98,400 90,800 189,200 Mar. 669,000 2,552,000 250,000 88,000 37,000 401 104,200 36,300 140,.50O April 527,000 2,846,000 247,000 134,000 7,000 45,000 411 109,000 58,300 167,300 May 492,000 2,940,000 276,000 187,000 10,000 19,000 411 117,500 79.600 197,100 June 340.000 2,940,000 283,000 103,000 12,000 410 124,200 45,100 169.300 July 260.000 2,882,000 298,000 75,000 14,000 407 125,400 31.600 157,000 Aug. 223.000 2,755,000 304,000 63,000 13,000 400 126,700 26.200 152,900 Sept. 205,000 2,604,000 282,000 48,000 10,000 304 120,000 20,400 140.400 Oct. 235,000 2,469,000 278,000 48,000 7,000 388 113.400 19,500 132,900 Nov. 257,000 2,371,000 264,000 81,000 5,000 384 110,300 33,800 144,100 Dec. Total or average 267,000 2,278,000 273,000 15.000 380 109,400 5,900 115,300 5,355,000 3,226,000 1,146,000 78.000 930,000 64,000 398 113,000 40,200 153.200 1909 Jan. 3,260.000 2,257,000 242,000 218,000 2,551,000 383 97,400 87.100 184,500 Feb. 2,526,000 2,506,000 227,000 242,000 1,938,000 386 101,900 108,100 210,000 Mar. 977,000 2,625,000 249,000 197,000 247,000 401 104.200 81,700 185,900 April May 758,000 2,909,000 249,000 229,000 7,000 10,000 230,000 409 109,000 100,100 209,100 581,000 2,940,000 276.000 216,000 10,000 79,000 410 117,500 91,500 209,000 June 410,000 2,940,000 282,000 171,000 12,000 3,000 410 124,200 74,900 199,100 July 308,000 2,882.000 298,000 123,000 14,000 406 125,400 51,700 177,100 Aug. 264,000 2,755,000 304,000 98,000 13,000 400 126,700 40,900 167.600 Sept. 246,000 2,604,000 282,000 89,000 10,000 394 120,000 37,800 157,800 Oct. 284,000 2,469.000 278.000 97,000 7,000 388 113,400 39,400 152,800 Nov. 538,000 2,371.000 264,000 174,000 5,000 384 110,300 72,500 182,800 Dec. Total or average 721,000 2,466.000 268.000 245,000 39,000 395 109.400 100,600 210,000 10,871.000 3,217,000 2,099,000 78,000 4,785,000 312,000 397 113,400 73,600 187,000 1910 Jan. 708,000 2,637,000 235.000 139,000 327,000 398 97,400 57,000 151,400 Fob. 847,000 2.644,000] 221,000 138,000 358,000 399 101,900 62.900 164,800 Mar. 1,239,000 2.774,000 247,000 239.000 351,000 236.000 406 104,200 100,400 204,600 April May 665,000 2,940,000 249,000 232,000 7,000 177,000 408 109,000 101.000 210,000 415.000 2,940,000 276,000 128,000 10,000 1,000 412 117,.500 54,400 171,900 June 2S2,00U 2,910,000 282,000 46,000 12,000 412 124,200 20,100 144,300 July 251.000 2.882,000 207,000 70,000 14,000 408 125,400 29,400 1.54,800 Aug. 236.000 2,755,000 301,000 70.000 13.003 400 126,700 23.200 155,900 Sept. 214,000 2,604,000 282,000 57.000 10.000 394 120,000 24,200 144,200 Oct. 231,000 2,469,000 278.000 44.000 7,000 388 113.400 17,900 131,300 Nov. 274.000 2.371,000 265,000 97,000 5,000 383 110,300 40,300 150,600 Dec. Total or average 436,000 2,278.000 274,000 183,000 380 109,400 73,000 182,400 5,801,000 3,210,000 1,443,000 78.000 1,036,000 414,000 399 113,400 50.800 164,200 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 273 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 114.) Installed capacity of power plant 400,000 k.v.a. P.F.=0.80. Flood control, holding maximum space required (454,000 ac .-ft.) In reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Power draft Release Average power yield Year and reservoir through turbines in through Waste Average in kilowatis month at acre-feet Evapora- flood over (Load factor= 0.75) beginning tion in acre-ieet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet *Prunary Second- ary Total 1907 2.325,000 231,000 249,000 295,000 388 94,100 100,900 195,000 Jan. 2.486,000 221,000 252,000 1,163,000 383 98,500 111,500 210,000 Feb. 2,486,000 249,000 273,000 1,593,000 383 100,500 109,500 210,000 Mar. 2,486,000 244,000 196,000 7,000 250,000 93,000 400 105.300 84,000 189,300 April 2,940,000 267,000 229,000 10,000 140,000 410 113,.300 96,700 210,000 May 2,940,000 273,000 207,000 12,000 409 119,700 90,300 210,000 June 2,869,000 289,000 213,000 14,000 404 121,100 88,900 210,000 July 2,687,000 296,000 203,000 13,000 394 122,300 83,600 205,900 Aug. 2.466,000 277,000 94,000 9 000 386 115,800 39,300 155,100 Sept. 2.338,000 272,000 74.000 7.000 ' 382 109,500 29,700 139,200 Oct. 2,246,000 259,000 80,000 4,000 378 106,500 32,900 139,400 Nov. 2,159,000 269,000 194,000 374 105,600 76,200 181,800 Dec. Total or average 3,147,000 2,264,000 76,000 3,307,000 233.000 391 109,400 78,500 187,900 2,175,000 232,000 121,000 240,000 386 94,100 48,500 142,600 1908 Jan. 2,486,000 226,000 258,000 486,000 388 95,100 111,600 206,700 Feb. 2,486,000 248,000 269,000 152,000 389 100,500 109,400 209,900 Mar. 2,486,000 247,000 49,000 7,000 395 105,300 20,700 126,000 April 2,710,000 270,000 141,000 10,000 405 113,300 59,000 172,300 May 2,781,000 275,000 104,000 11,000 404 119.700 45,100 164.800 June 2,730,000 291,000 75,000 14,000 400 121,100 31,200 152.300 July 2,610,000 298,000 63,000 12,000 394 122,300 25.900 148,200 Aug. 2,466,000 276,000 48,000 9,000 387 115,800 20,100 135,900 Sept. 2,338,000 272,000 48,000 7,000 382 109,500 19,200 128,700 Oct. 2,246,000 259,000 81,000 4,000 378 106,500 33,300 139,800 Nov. 2,159,000 269,000 82,000 372 105,600 32,300 137,900 Dec. Total or average 3,164,000 1,339,000 74,000 878,000 390 109,100 46,200 155.300 2,075,000 236,000 226,000 2,387,000 378 04,100 89,700 183,800 1909 Jan. 2,486,000 222,000 253,000 2,051,000 380 98,500 111,500 210.000 Feb. 2,486,000 248,000 273,000 456,000 386 100,500 109,500 210,000 Mar. 2,486,000 246,000 123,000 7,000 77,000 397 105,300 52,500 157,800 April 2,789,000 269,000 230.000 10,000 406 113,300 96,700 210,000 May 2,861,000 275,000 208,000 12,000 406 119,700 90,300 210,000 June 2,776,000 290,000 170,000 14,000 400 121,100 70,800 191,900 July 2,610,000 298,000 98,000 12,000 394 122,300 40,300 162,600 -^ug. 2,466,000 277,000 88,000 9,000 386 115.800 36,800 152,600 Sept. 2,338,000 273,000 96,000 7,000 381 103,500 38,400 147,900 Oct. 2,246,000 258,000 179,000 4,000 378 106,500 73,600 180,100 Nov. 2,343,000 261,000 258,000 84,000 387 105,600 104,400 210,000 Dec. Total or average 3,153,000 2.202,000 75,000 5,055,000 390 109,400 76,100 185,500 2,461,000 230,000 229 000 224,000 389 94,100 93,800 187,900 1910 ,Ian. 2,486,000 219,000 249,000 379,000 388 98,500 111,500 210,000 Feb. 2,486,000 248,000 273,000 718,000 386 100,500 109,500 210,000 Mar. 2,480,000 246,000 92,000 7,000 66,000 397 105.300 38,800 144,100 April 2,740,000 270.000 94,000 10,000 404 113,300 39,400 1,52,700 May 2,781,000 275,000 47,000 11,000 404 119,700 20,400 140,100 June 2,730,000 200,000 70,000 14,000 400 121,100 29,200 150,300 July 2,610,000 298,000 70,000 12.000 394 122,300 28,800 151,100 Aug. 2,466,000 270,000 ! 57,000 9,000 387 115,800 23,900 139,700 Sept. 2,338,000 272,000. '14,000 7,000 382 109,500 17.700 127,200 Oct. 2,246,000 259,000 98,000 4,000 377 103,500 40,300 146,800 Nov. 2.159,000 268,000 252,000 372 105.600 98,500 204.100 Dec. Total or average 3,151,000 1,575,000 74,000 1,387.000 390 109,400 54.100 163,500 274 WATER RESOURCES OF CALIFORNIA. TABLE 4a (Continued). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Esti- Maximum reservoir space equired 454,000 ac.- ft. mated run-off at Year and Stage of Power draft Release Average power yield month dam reservoir through turbines in through Waste Average in kilowatts sitf at acre-feet Evapora- flood over (Load factor= 0.75) in acre-feet beginning of tion in acre-feet control outlets spillway in head iu feet month in acre-feet Primary Second- ary in acre-feet acre-feet •Primary Second- ary Total 1911 Jan. 700,000 2,257,000 241,000 18.000 193,000 384 97,400 7,300 104.700 Feb. 848,000 2,505,000 226,000 168,000 377,000 389 101,900 75,000 176.900 Mar. 1,278,000 2,582,000 253,000 246,000 548,000 395 101.200 100.900 205,100 April 062,000 2,813.000 249,000 232,000 7,000 99,000 248,000 407 109,000 101,000 210.000 May 671.000 2.940.000 278,000 219.000 10,000 164,000 408 117,500 92,500 210,000 .lune 431,000 2,940,000 282,000 182,000 12,000 13,000 410 124,200 79,600 203.800 July 287,000 2,882,000 298,000 102,000 14,000 406 125,400 42.900 168,3(J() Aug. 244,000 2.755,000 304,000 78,000 13,000 400 126,700 32.500 159,200 Sept. 2.31,000 2,604,000 282,000 74,000 10,000 394 120,000 30,700 1.50,700 Oct. 246,000 2,469,000 278,000 59,000 7,000 388 113,400 24.100 137,500 Nov. 241,000 2,371,000 264,000 65,000 5,000 384 110,300 26,900 137,200 Dec. Total or 244,000 2,278,000 273,000 380 109,400 109,400 average 6,383,000 3,228,000 1.443,000 78,000 1,217.000 425,000 306 113.400 50,800 164,200 1912 Jan. 517,000 2,249,000 239,000 388 97,400 97,400 Feb. 396,000 2,527,000 221,000 399 98,400 98,400 Mar. 635,000 2,702,000 246,000 118,000 33,000 409 104,200 50,300 154,500 April 487,000 2,940.000 247,000 182,000 7,000 51,000 411 109,000 80,000 189,000 May 714,000 2,940,000 277,000 217,000 10,000 210,000 410 117,500 91,900 209,400 June 405,000 2,040,000 282,000 158.000 12,000 11,000 411 124,200 69,000 193.200 July 274,000 2,882,000 298,000 89,000 14,000 406 125.400 37,500 162,900 Aug. 238,000 2,755,000 304,000 72,000 13,000 400 126,700 30,000 156.700 Sept. 242,000 2,604,000 282,000 85,000 10,000 394 120,000 36,000 156,000 Oct. 226,000 2,469,000 278,000 39,000 7,000 388 113.400 15,900 129,300 Nov. 4.32,000 2,371,000 264,000 210,000 5,000 385 110,300 87,100 197,400 Dec. Total or average 369,000 2,324,000 273,000 163,000 380 109,400 64.500 173,900 4,935,000 3,211,000 1,333,000 78,000 305,000 398 113,000 46,900 159.900 1913 Jan. 763,000 2,257,000 240,000 111,000 137,000 386 97.400 45.000 142.400 Feb. 387,000 2,532,000 222.000 17,000 (1 399 101,900 7.600 109.500 Mar. 441.00(1 2,680.000 247,000 406 104.200 104,200 April May 085,000 2.874,000 219,000 200,000 7,000 163.000 409 109,000 87.600 190,600 .521,000 2, '.140,00(1 27(),0()0 201,000 10,000 34,000 411 117,500 85,500 203,000 June 321,000 2,940,000 283.000 84.000 12,000 410 124,200 36,800 161,000 July 21)3.000 2,882,000 298.000' 78,000 14,000 407 125,400 32,800 158,200 Aug. 232.00(1 2,7.55,(W() 304.000 60,000 13,000 400 120,700 27.600 154,300 Sept. rK),(K)(l 2,691,001 282,000 33,000 10,000 394 120,000 14.000 134,000 Oct. 202,000 2,1(i9,0()Ot 278.000 15,000 7,000 388 113,400 6.000 119,400 Nov. 310,000 2,371,000 265,000 105,000 5,000 383 110,300 43,600 153,900 Dec. 696.000 2,312.000 272.000 183,000 381 109,400 72,900 182,300 Total or average 5,017,000 3,216,000 1,093,000 78,000 137,000 197,000 398 113,400 38,500 151,900 1914 Jan. 2.707,000 2,.553,000 238,000 258,000 2,075,000 392 97,400 105,200 202,600 Feb. 1,3.59 000 2,779.00( 224.000 2;;7,ooo 903,000 394 101,900 108,100 210,000 Mar. 987,000 2,774. 00( 249,000 240.000 374,000 402 104,200 99,600 203,800 Awil May i,i3;,()oo 2,8'.I8,00( 249.000; 231,(K)0 7,000 6,000 602,000 407 109,000 100,700 209,700 703,000 2.940,()O( 278.0001 220,000 10,000 105,000 408 117,500 92,.5()0 2in.ono Juno 452.000 2,940,00( 28H,(IOOi 196,000 12,000 13,000 410 124,200 85,800 210.000 July 309,(H)0 2,S8S,000; 298.000! 1.30,000 14,000 406 125,400 54,800 180 200 Aug. 2I8,0(H) 2.7.'')5.00(li 301.000! 82,000 13,000 400 120,700 34,100 100,800 Sept. 225,(K)0| 2,(;0I,000| 2S2.()00; 68,000 10,000 394 120,000 28,800 148,800 Oct. 269,(M)0 2.46!I,0(M) 278.000, 82,000 7,000 388 113,400 33,200 146,600 Nov. 252,000 2,371,000 205,000 75,000 5,000 383 110.300 31,100 141,400 Dec. 347,000 2,278,000 273,000 95,000 380 109.400 37,900 147,300 Total or average 9,085,000 3.221,000 1,914,000 78,000 3,358,000 810,000 397 113,400 67.400 180,800 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 275 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 1 14.) Installed capacity of power plant 400,000 k.v.a. P.F.=0.80. Flood control, holding maximum space required (454,000 ac -ft.) in reserve throughout flood season Ma.ximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Powe r draft Release Average power yield Year and reservoir through turbines in through Waste Average in kilowatts month at acre -feet Evapora- flood over (Load factor=: 0.75) beginning tion in acre-feet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1911 2,075,000 237,000 9,000 43,000 376 94,100 3,800 97,900 Jan. 2,486,000 220,000 250,000 378,000 384 98,500 111,500 210,000 Feb. 2,48r.,000 249,000 267,000 762,000 385 100,500 107,700 208,200 Mar. 2,480,000 246,000 164,000 7,000 195,000 398 105,300 70,000 175,300 April 2,836,000 267,000 229,000 10,000 61,000 410 113,300 96,700 210,000 May 2,940,000 273,000 206,000 12,000 13,000 410 119,700 90,300 210,000 June 2,867,000 290,000 212,000 14,000 402 121,100 88,900 210,000 July 2,638.000 298,000 106,000 12,000 394 122,300 43,500 165,800 Aug. 2,466,000 277,000 73,000 9,000 386 115,800 30,600 146,400 Sept. 2,338,000 272,000 59,000 7,000 382 109,500 23,700 133,200 Oct. 2,246,000 259,000 65,000 4,000 378 106,500 26,700 133,200 Nov. 2,159,000 269,000 59,000 372 105,600 23,300 128,900 Dec. Total or average 3,157,000 1,699,000 V5,000 1,378,000 74,000 390 109,400 59,300 168,700 2.075,000 236,000 378 94,100 94,100 1912 Jan. 2,.S50,000 226,000 40,000 390 95,100 17,700 112,800 Feb. 2,486,000 246,000 269,000 120,000 390 100,500 109,500 210,000 Mar. 2,486,000 247,000 37,000 7,000 395 105,300 15.400 120,700 April 2,682,000 269,000 207,000 10,000 406 113,300 87,100 200,400 May 2,910.000 274,000 206,000 12,000 408 119,700 90,300 210,000 June 2,823,000 290,000 183,000 14,000 401 121,100 76,300 197,400 July 2,610,000 298,000 72,000 12,000 393 122,300 29,600 151.900 Aug. 2,466,000 277,000 84,000 9,000 386 115,800 35,100 150,900 Sept. 2,338,000 272,000 39,000 7,000 382 109,.500 15,600 125,100 Oct. 2,246,000 258,000 220,000 4,000 378 106,500 90,100 196,600 Nov. 2,196,000 268,000 220,000 372 105,600 85,800 191,400 Dec. Total or average 3,161,000 1,577,000 75,000 120,000 390 100,100 54,,500 163,600 2,077,000 234,000 98,000 22,000 381 94,100 39,800 133,900 1913 .Tan. 2,486,000 218,000 169,000 390 98,500 76,300 174,800 Feb. 2,486,000 245,000 196,000 391 100,500 80,100 180,600 Mar. 2,486,000 246,000 97,000 7,000 69,000 397 105,300 41,100 146,400 April 2,752,000 270,000 212,000 10,000 404 113,300 89,000 202,300 May 2,781,000 276,000 85,000 11,000 404 119,700 36,800 156,50.) Juno 2,730,000 290,000 79,000 14,000 400 121,100 32,900 154,000 July 2,610,000 298.000 66,000 12,000 394 122,300 27,200 149,500 Aug. 2,466,000 276,000 33,000 9,000 387 115,800 13,900 129,700 Sept. 2,338,000 272,000 15,000 7,000 382 100,500 6,000 115,500 Oct. 2,246,000 259,000 107,000 4,000 377 106,500 43,800 150,300 Nov. 2,192,000 268,000 231,000 373 105,600 90,500 196,100 Dec. Total or averiige 3,152,000 1,388,000 74,000 91,000 390 109,400 48,000 157,400 2,389,000 235,000 291,000 2,174,000 379 94,100 115,900 210,000 1914 Jan. 2,486,000 220,000 251,000 888,000 385 98,500 111,.500 210,000 Feb. 2,486,000 248,000 273.00) 466,t00 386 100,500 10i),50U 210.000 Mar. 2,486,000 244,000 190,000 7,000 107,000 75,000 400 105,300 81,800 187,100 April 2,940,000 267,000 229,000 10,000 197,000 409 113,300 96,700 210,000 May 2,940,000 273,000 207,000 12,000 409 119,700 90,300 210,000 June 2,900,000 288,000 214,000 14,000 404 121,100 88,900 210,000 July 2,693,000 2it6,000 166,000 13,000 395 122,300 68,400 190,700 Aug. 2,466,000 276,000 68,000 9,000 387 115,800 28,500 144,300 Sept. 2,338,000 272,000 82,000 7,000 382 109,500 32,900 1 12,400 Oct. 2,246,000 259,000 76,000 4,009 378 105,500 31.300 137,800 Nov. 2,159,000 269,000 162,000 372 105,600 63,700 169,300 Dec. Total or average 3,147,000 2,209,000 76,000 3,695,000 272,000 390 109,400 76,500 185,900 276 WATER RESOURCES OF CALIFORNIA. TABLE 4a (Continued). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Esti- Maximum reservoir space required 454,000 ac. ft. mated run-off at Year and Stage of Power draft Release Average power >ield moDtb dam reservoir through turbines in through Waste Average in kilowatts site at acre-feet Evapora- flood over (Load factor=0.75) in acre-ieet beginning tion in acre-feet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1915 Jan. 895.000 2,257,000 239,000 101,000 324,000 388 97,400 40,900 138,300 Feb. 2,298,000 2,488,000 228,000 242.000 1.625,000 386 101,900 108,100 210,000 Mar. 1,264,000 2,691,000 250,000 256,000 522,000 399 104.200 105.800 210,000 April l,lo;),000 2,927,000 249.000 234,000 7,000 38,000 618.000 405 109,000 101,000 210,000 May 1,2511,000 2,940.000 279,000 220,000 10,000 747,000 406 117,500 92,.500 210.000 .Func 572,000 2.040,000 283,000 195,000 12,000 99,000 410 124,200 85.800 210,000 July 343,000 2,923,000 298,000 199,000 14,000 406 12.5,400 83.900 209,300 Aug. 266,000 2,755,000 304,000 100,000 13,000 400 126,700 41,709 168,400 Sept. 215,000 2,604,000 282.000 58,000 10,000 394 120,000 24.700 144,700 Oct. 233,000 2,469,000 278,000 46.000 7,000 388 113,-400 18,700 132,100 Nov. 254,000 2,371,000 264,000 78,000 5,000 384 110,300 32,400 142,700 Dec. Total or 699,000 2,278,000 270.000 235.000 387 109.400 94,900 201,300 average 9,454,000 3,224.000 1.964.000 78,000 2,509.000 1,464.000 396 113.400 69,000 182.400 1916 Jan. 1,160,000 2,472,000 240,000 225,000 681,000 388 97,400 90,700 188,100 Feb. l.OHi.OOO 2,492.000 237.000 252.000 1,077,000 384 98,400 107,900 206,300 iMar. 1,215,000 2,542.000 252,000 236,000 391,000 396 104,200 97,000 201,200 April 678,000 2,878,000 249,000 211.000 7.000 149,000 410 109.000 92,400 201,400 May 485.000 2.910.000 276,000 173,000 10,000 26,000 412 117.500 73,500 191,000 June 353,000 2,940,000 283,000 116,000 12,000 410 124,200 50.800 175,000 July 316,000 2,88ii 000 298,000 131,000 14.000 407 125,400 55.200 180,600 Aug. 214,000 2,755,000 304,000 78.000 13,000 400 126,700 32,.500 159,200 Sept. 213,000 2,604,000 282,000 56.000 10,000 394 120,000 23,800 143,800 Oct. 236,000 2,469,000 278,000 49.000 7,000 388 113,400 19,900 133,300 Nov. 242,000 2,371,000 264,000 66,000 5,000 384 110,300 27,500 137,800 Dec. Total or average 303,000 2,278.000 273.000 111.000 380 109,400 44.500 153,900 7.127,000 3.236.000 1.704.000 78.000 2.149,000 175.000 396 113,000 59.500 172.500 1917 Jan. 312,000 2,257,000 242.000 382 97.400 97.400 Feb. 760,000 2,327,000 226,000 26.000 178,000 387 101,900 11.600 113,500 Mar. 459,000 2,057,000 247,000 8.000 406 104,200 3,500 107.700 April May 906,000 2,861,000 249,000 196.000 7.000 375,000 408 109.000 85.600 194.600 580,000 2,940,000 276,000 210,000 10,000 84,000 411 117.500 89,000 206,500 June 32;',000 2,940,000 283,000 92,000 12.000 410 124.200 40.300 164,.500 July 238,000 2,882,000 297,000 54.000 14,000 408 125,400 22,700 148,100 Aug. 211,000 2,755,000 303,000 49.000 13,000 402 120,700 20.400 147.100 Sept. 185,000 2,(101,000 282,000 28.000 10.000 394 120,000 11.900 131.900 Oct. 200.000 2,469,000 278.000 13.000 7.000 388 113,400 5.400 118.800 Nov. 221,000 2,371,000 264.000 48.000 5.000 384 110.300 20.000 130,300 Dec. 298.000 2.278,000 273.000 46.000 380 109.400 18.400 127,800 Total or average 4,705,000 3.220,000 770.000 78.000 178,000 459.000 397 113,400 27.400 140,800 1918 Jan. 249.000 2,257.000 243,000 380 97.400 97,400 Feb. 399,000 2.263,000 229,000 383 101.900 101,900 Mar. 772,00(J 2,4.33.000 251,000 8.000 6.000 398 104,200 3,400 107.600 April May .556.000 2,940,000 247,000 208,000 7,000 94,000 411 109.000 91,100 200,100 3II,(H)( 2,940,000 270,000 28.000 10,000 412 117.500 12.000 129.500 Juno 232,000 2,910,000 282,000 12,000 412 124,200 124,200 July 200,000 2,878,000 297,000 12.000 14,000 408 125.400 5,100 130.500 Aug. 192.000 2,7.')5.OO0 303,000 27.000 13.000 402 126.700 11,200 137.900 Sept. 186.00( 2.604.000 282.000 29.000 10.000 394 120.000 12,400 132,400 Oct. 258.000 2,469.000 278,000 71.000 7.000 388 113.400 28.900 142,300 Nov. 246.000 2.371.000 264.000 70.000 6.000 384 110.300 29.000 139.300 Dec. 258,000 2.278,000 270,000 0.000 380 109.400 3.600 113.000 Total or average 3.862.000 3,222.000 462.000 78.000 100.000 396 113.400 16.300 129.700 •Total primary power pro;l\iction in February of loap yi^ars taken the same as in other years. THE CONTROL OP Fr,OOD« BY RESERVOIRS. 277 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 1 14.) Installed capacity of power plant 400,000 k.v.a. P.F. = 0.80. Flood control, holding maximum space required (454,000 ac -ff.) In reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 seo.-f t. Stage of Power draft Release Average power yield Year and reservoir through turbines in through Waste Average n kilowatts month at acre-feet Evapora- flood over (Load factor=0.75) beginning tion in acre-feet control outlets spillway in power head in feet of , month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1915 2,075,000 234,000 37,000 213,000 382 94,100 14,900 109,000 Jan. 2.486,000 223,000 253,000 1,822,000 378 98,500 111,500 210,000 Feb. 2,486,000 250,000 274,100 740,000 382 100,500 109,500 210,000 Mar. 2.486,000 245,000 179,000 7,000 267,000 7,000 399 105,300 70,800 182,100 April 2,940,000 268,000 231,000 10,000 747,000 408 113,300 96,700 210,000 May 2,940,000 274,000 206,000 12,000 80,000 408 119,700 90,300 210,000 June 2,940,000 288,000 211,000 14,000 406 121,100 88,900 210,000 July 2,770,000 295,000 213,000 13,000 397 122,300 87,700 210.000 Aug. 2,515,000 276,000 107,000 9,000 387 115,800 44,900 160,700 Sept. 2,338,000 272,000 48,000 7,000 382 109,500 18,400 127,900 Oct. 2,246,000 259,000 78,000 4,000 378 106,500 32,100 138,600 Nov. 2,159,000 263,000 252,000 381 105,600 100,100 205,700 Dec. Tnfnl nr 3,117,000 2,087,000 76,000 3,042,000 834,000 391 109,400 72,400 181,800 X Ulai Ul average 2,343,000 232,000 213,000 578,000 386 94,100 85,900 180,000 1916 Jan. 2,486,000 226,000 261,000 1,129,000 386 95,100 111,600 206,700 Feb. 2,486,000 249,000 272,000 694,000 384 100,500 109,500 210,000 Mar. 2,486,000 246,000 99,000 7,000 61,000 397 105,300 41,900 147,200 April 2,751,000 270,000 175,000 10,000 404 113,300 73,400 186,700 May 2,781,000 276,000 117,000 11,000 404 119,700 50,700 170,400 June 2,730,000 291,000 131,000 14,000 400 121,100 54,600 175,700 July 2,610,000 298,000 78,000 12,000 394 122,300 32,000 154,300 Aug. 2,466,000 270,000 56,000 9,000 387 115,800 23,500 139,300 Sept. 2,338,000 272,000 49,000 7,000 382 109,500 19,600 129,100 Oct. 2,246,000 259,000 66,000 4,000 378 106,500 27,100 133,600 Nov. 2,159,000 269,000 178,000 372 105,600 70,000 175,600 Dec. 3,164,000 1,695,000 74,000 2,462,000 389 109,100 58,300 167,400 average 2,075,000 239,000 372 94,100 94,100 1917 Jan. 2,148,000 223,000 27,000 172,000 377 98,500 11,900 110,400 Feb. 2,486,000 245,000 214,000 391 100,500 87,500 188,000 Mar. 2,486,000 245,000 172,000 7,000 55,000 399 105,300 73,500 178,800 April 2,913,000 267,000 226,000 10,000 57,000 410 113,300 96,700 210,000 May 2,933,000 274,000 209,000 12,000 407 119,700 90,300 210,000 June 2,767,000 231,000 90,000 14,000 400 121,100 37,.500 158,600 July 2,610,000 298,000 48,000 12,000 394 122,300 19.800 142,100 Aug. 2,466,000 276,000 28,000 9,000 388 115,800 11,700 127,500 Sept. 2,338,000 272,000 13,000 7,000 382 109,500 5,200 114,700 Oct. 2,246,000 259,000 48,000 4,000 378 106,500 19,700 126,200 Nov. 2.159,000 269,000 113,000 372 105,600 44,400 150,000 Dec. Total or average 3,158,000 1,188,000 75,000 227,000 57,000 389 109,400 41,700 151,100 2,075,000 240,000 370 94,100 94,100 1918 Jan. 2,084,000 224,000 376 98,500 98,500 Feb. 2.259,000 249.000 105,000 191,000 385 100,500 42,500 143,000 Mar. 2,486,000 246,000 58,000 7,000 20,000 397 105,300 24,400 129,700 April 2,711,000 270,000 10,000 404 113,300 113,300 May 2,745,000 276,000 11,000 403 119,700 • 119,700 June 2,690,000 291,000 14,000 400 121,100 121,100 July 2,585,000 296,000 3,000 12,000 394 122,300 1,200 123,500 Aug. 2,466,000 276,000 29,000 9,000 388 115,800 12,200 128,000 Sept. 2,338,000 272,000 71,000 7,000 382 109,500 28,500 138,000 Oct. 2,246,000 259,000 70,000 4,000 378 106,500 28,800 135.300 Nov. 2,159,000 269,900 73,000 372 105,600 28,800 134,400 Dec. Total or average 3,168,000 409,000 74,000 211,000 387 109,400 14.000 123.400 278 WATER RESOURCES OP CALIFORNIA. TABLE 4a ^Continued). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa fFor corresfX)nding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operatin g diagram Maxinum controlled flow at Red Bluff 12.5.000 sec.-ft. Esti- mated run-off Maximum reservoir space required 454,000 ac. ft. Year and at Stage of Power draft Release Average power yield month dam reservoir tlirough turbines in through Waste Average n kilowatts site at acre-feet Evapora- flood over (Load factor=0.75) in acre-feet beginning of tion in acre-feet control outlets spillway in power head in feet month in acre-feet Primary Second- ary in acre-feet acre-feet •Primarj Second- ary Total 1919 Jan. -.587.000 2.257,000 240,00C 71,000 1 34,000 385 97.400 29,000 126,400 Fcl). 1,163.000 2.499,000 226,000 222,000 • 671,000 387 101.900 99,600| 201,500 Mir. 959.000 2,543,000 251,000 230,000 196.000 397 104,200 9.5,200; 199,400 April 7.i2.000 2.825,000 249,000 22*,000 7.000 18,000 139.000 409 109,000 97.600 206,600 M ly 438.000 2,940,000 277,000 151,000 10,000 410 117,500 64,100 181,600 .Ii;iie 2.52.000 2,940,000 282,000 16.000 12,000 412 124,200 7,100 131.300 July 219.000 2,882,000 297,000 35,000 11.000 408 125,400 14,800 140,200 Au<. 199.000 2,755,000 303,000 ! 34,000 13,000 402 126,700 14,200 140.900 Sept. 168,000 2,604,0001 282,000 ; 11,000 10,000 394 120.000 4,600 124,600 Oct. 203.000 2,469,000 278,000 i 16,000 7.000 388 113,400 6,500 119.900 Nov. 186,000 2,371,000 264,000 1 10.000 5,000 384 110,300 4,200 114.500 Dec. 180,000 2,278,000 274,000 378 109,400 109,400 Totil or average 5,306,000 3.223.000 1.020,000 78,000 919,000 139.000 396 113,400 36,000 149.400 1920 Jan. 207,000 2.184,000 245,000 375 97,400 97.400 Feb. 176,000 2,146,0001 233,000 1 372 98,400 98,400 Mar. 372,000 2.080. nnn on? oon 374 104.200 104,200 April 493,000 2,'l98'iH'i J', J 6.000 383 109,000 109,000 -May 286,000 2.423 n"i _-"-> 9.000 388 117,500 117..500 June 216,000 •: •,-: 10.000 386 124,200 124.200 July 192,0011 12.000 380 125.400 125,400 Aug. 176,000 . 11,000 372 126.700 126,700 Sept. 140.000 8,000 363 120,000 120,000 Oct. 180,0011 6,000 354 113.400 113,400 Nov. 896,001 i 25,000 4,000 359 110,300 10,400, 120,700 Dec. Total or 1,121,000 ^,oi:',V\Ji) .iOD.UUO 245.000 202,000 395 109,400 100,600 210,000 average 4,455,000 3,374,000 270,000 66,000 202,000 375 113,000 9,400 122,400 1921 Jan. 1,492,000 2,727,000 239,000 277,000 1.050,000 390 97.400 112.600 210.000 Feb. 1,035,000 2.653,000 226,000 240,000 660,000 390 101.900 108,100 210,000 Mar. 982,000 2.562,000 252,000 244,000 226,000 396 104,200 100.900 205.100 April May 559,000 2,822,000 246,000 164,000 7,000 24,000 411 109,000 71,900 180.900 493,000 2,940,000 276,000 195,000 10,000 12,000 411 117,500 83,200 200,700 June 316,000 2,940,000 283,000 79,000 12,000 410 124,200 34,600 158,800 July 220,000 2,882,000 297,000 36,000 14,000 408 125,400 15,200 140,600 Aug. 192,000 2,755,000 303,000 27.000 13.000 402 126,700 11,200 137,900 Sept. 175,000 2,604,000 282,000 18,000 10,000 394 120.000 7,800 127,800 Oct. 196,000 2,469,000 277,000 7.000 389 113,400 113,400 Nov. 205.000 2.381,000 264,000 39,000 5,000 384 110.300 16,300 126,600 Dec. Total or 390,000 2,278,000 273,000 72,000 381 109.400 28,900 138,300 average 6,255,000 3,218,000 1,391,000 78,000 1.936.000 36,000 397 113,400 48,900 162,300 1922 Jan. 300,000 2,323,000 240,000 387 97,400 0| 97,400 Feb. 679,000 2,383,000 225,000 44,000 136,000 o' 392 i 101,900 19,900 121,800 Mar. 567,000 2,657,000 246.000 17,000 21,000 407 104,200 7,300l 111,500 April May 604,000 2.940.000 248,090 214,000 7,000 135,000 410 109,000 93,600, 202,600 577,000 ?.940,000 276.000 209,000 10,000 82,000 411 117,500 88,300; 205.800 June 317,000 2,940,000 283,000 80,000 12,000 410 1 124,200 35.000 159,200 July 203,000 2,882.000 297,000 19,000 14,000 408 125.400 7,900 133,300 Aug. 182,000 2,755,000 303,000 17,000 13.000 402 126,700 7,100 133,800 Sept. 161,000 2,604,000; 282.000 4,000 10,000 394 120,000 1,700 121,700 Oct. 208.000 2.469,000 278,000 21,000 7,000 388 113,400 8,600 122,000 Nov. 244,000 2,371.000 264,000 68.000 5,000 384 110,300 28,300 138,600 Dec. Total or 462,000 2,278,000 273.000 139.000 380 109,400 55,100j 164,500 avenge 4.604,000 3,215,000 832,000 78,000' 1 136,000| 238.000' 898 113,400 29,400 142,800 _^Tot^_Erimary power production in February of leap years taken the game aa in other years. THE CONTROL OF FLOODS HY RERERVOIRR. 279 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 114.) Installed capacity of power plant 400,000 k.v a. P.F. = 0.80. Flood control, holding maximum space requirea (454,000 ac -ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-ft. Stage of Power draft Release Average power yield reservoir through turbines in through Waste Average m kilowatt Year and at acre -feet Evapora- flood over (Load factor=0.75) month beginning tion in acre-feet control outlets spillway in power head in leet of month in acre-feet Primary Second- ary in acre-feet acre-ieet *Primary Second- ary Total 2,075,000 236,000 377 94,100 94,100 1919 Jan. 2,426,000 220,000 188,000 695,000 386 98,500 83,800 182,300 Feb. 2,486,000 248,000 270,000 441,000 386 100,500 103,500 210,000 Mar. 2,486,000 246,000 109,000 7,000 109,000 396 105,300 46,400 151,700 April 2,767,000 270,000 144,000 10,000 405 113,300 60,500 173,800 May 2,781.000 275,000 17.000 11,000 405 119,700 7,400 127,100 June 2,730,000 290,000 35,000 14,000 401 121,100 14,700 135,800 July 2,610.000 296,000 35,000 12,000 394 122.300 14,400 136.700 Aug. 2,466,000 276,000 11,000 9,000 388 115,800 4,600 120,400 Sept. 2,338,000 272,000 16,000 7,000 382 109,500 6,500 116,000 Oct. 2,246,000 259,000 10,000 4,000 378 106,500 4,200 110,700 Nov. 2,159,000 268,000 372 105,600 105,600 Dec. Total or average 3,156,000 835,000 74,000 1,245,000 389 109,400 29,000 138,400 2,071,000 239,000 370 94,100 94,100 1920 Jan. 2,039,000 236,000 367 95,100 95,100 Feb. 1,979,000 257.000 368 100,500 100,500 Mar. 2,094,000 256,000 6,000 377 105,300 105,300 April 2,325,000 281,000 9,000 384 113,300 113,300 May 2,321,000 288,000 10,000 382 119,700 119,700 June 2,239,000 306,000 12,000 376 121,100 121,100 July 2,113,000 314.000 11,000 368 122,300 122.300 Aug. 1,964,000 293,000 8,000 360 115,800 115,800 Sept. 1,803,000 293,000 6.000 351 109,500 109,500 Oct. 1,684,000 266,000 4,000 365 106.500 106,500 Nov. 2,310,000 261,000 192,000 492,000 386 105,600 77,300 182,900 Dec. Total or average 3,290,000 192,000 66,000 492,000 371 109,100 6,500 115,600 2,486,000 233,000 288,000 971,000 385 94,100 115,900 210,000 1921 Jan. 2,486,000 220,000 250,000 565,000 385 98,500 111,500 210,000 Feb. 2,486,000 248,000 270,000 464,000 386 100,500 109,500 210,000 Mar. 2,486,000 246,000 59,000 7,000 43,000 395 105,300 24,400 129,700 April 2,690,000 270,000 122,000 10,000 404 113,300 51,100 164,400 May 2,781,000 276,000 80,000 11,000 404 119,700 34,700 154,400 June 2,730,000 290,000 38,000 14,000 400 121,100 15,100 130,200 July 2,610,000 296,000 28,000 12,000 394 122,300 11,600 133,900 Aug. 2,466,000 276,000 18,000 9,000 388 115,800 7,500 123,300 Sept. 2.338,000 272,000 9,000 7,000 382 109,500 3,600 113,100 Oct. 2,246,000 259,000 29,000 4,000 378 106,500 11,900 118,400 Nov. 2,159,000 268,000 120,000 373 105,600 47,200 152,800 Dec. Totil or average 3,154,000 1,309,000 74,000 2,043,000 390 109,400 45,100 154,500 2,161,000 237,000 376 94,100 94,100 1922 Jan. 2,224,000 221,000 62,000 134,000 383 98,500 28,000 126,500 Feb. 2,486,000 246,000 239,000 82,000 390 100,500 97,300 197,800 Mar. 2,486,000 247,000 59,000 7,000 80,000 395 105,300 24,400 129,700 April 2,697,000 270,000 178,000 10,000 405 113,300 74,900 188,200 May 2,816,000 276,000 116,000 11,000 404 119,700 50,300 170,000 June 2,730,000 290,000 19.000 14,000 400 121,100 7,900 129,000 July 2,610,000 296,000 18,000 12,000 394 122,300 7,400- 129,700 Aug. 2,466.000 276,000 4,000 9,000 388 115,800 1,700 117,500 Sept. 2,338,000 272,000 21,000 7,000 382 109,500 8,500 118,000 Oct. 2,246,000 259,000 68,000 4,000 378 106,500 27,900 134,400 Nov. 2,159,000 269,000 197,000 372 105,600 76,900 182,500 Dec. Total or average 3,159,000 981,000 74,000 296,000 389 109,400 33,900 143,300 280 WATER RESOURCES OP fALIFORXIA. TABLE 4a (Concluded). KENNETT COMPARISON OF WATER AND POWER YIELD, OPERATING PRI FOR TWO METHODS OF Monthly Summary of Computa (For corresponding yearly sum Height of dam 420 feet. Capacity of reservoir 2,940,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled flow at Red Bluff 125,000 sec.-ft. Esti- Maximum reservoir space required 454,000 ac. -ft. mated run-off Year and at Stage of Power draft Release Average power yield month dam reservoir through turbines in through Waste Average in kilowatts site at acre-feet Evapora- flood over (Load factor=^0.75) in acre-feet beginning tion in acre-feet control outlets spillway in power head in feet of _ month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1923 Jan. 467,000 2,328,000 240,000 130,000 385 97,400 52,400 149,800 Feb. 297,000 2,425,000 225,000 390 101,900 101,900 Mar. 287,000 2,497,000 253,000 393 104,200 104,200 .\i)ril 632,000 2,531,000 250,000 7,000 405 109,000 0! 109,000 May 322,000 2,906,000 275,000 3,000 10,000 412 117,500 1.300 118,800 .June 236.000 2,940,000 282,000 12,000 • 412 124,200 124,200 July 184,000 2,882,000 297,000 14,000 408 125,400 125,400 Aug. 10.5.000 2,755,000 303,000 13,000 402 126,700 126.700 .Sept. 157,000 2,604,000 282,000 10,000 394 120,000 120,000 Oct. 187,000 2,469,000 278,000 7,000 388 113,400 113,400 Nov. 176.000 2,371,000 264,000 5.000 384 110,300 110.300 Dec. Total or 184,000 2,278,000 274,000 379 109,400 O; 109.400 average 3,294.000 3,223,000 133,000 78,000 398 113,400 4.600 118,000 1924 Jan. 203,000 2,188,000 245.000 376 97,400 97,400 Feb. 332,000 2,146,000 231,000 378 98.400 98,400 Mar. 200,000 2,247,000 260,000 379 104,200 104.200 April May 176,000! 2,187,000 266,000 6,000 374 109,000 109,000 1.5.5,000! 2,091,000 301,000 8,000 367 117.500 117,500 June 141.000 1,937,000 315,000 9,000 358 124,200 124,200 July 140,000 1,754,000 341,000 10,000 345 125,400 125,400 Aug. 140,000i 1,543,000 360,000 8,000 330 126,700 126,700 Sept. 128,000 1,315,000 349,000 6,000 312 120,000 120,000 Oct. 178,000; 1,088.000 363,000 4.000 293 113,400 113,400 Nov. 317,000 899,000 356,000 2,000 282 110,300 110,300 Dec. Total or average 321,000 858,000 372,000 » 277 109,400 Q^ 109,400 2,431,000 3,759.000 53,000 339 113,000 O' 113,000 1925 Jan. 301,000 807,000 336,000 273 97,400 97.400 Feb. 1,769,000 772,000 264,000 326 101,900 101.900 Mar. 563,000 2,277,000 255.000 389 104,200 101,200 April May 926.000 2,585,000 250,000 124,000 7,000 190,000 403 109,000 53,800 162,800 474,000 2,940,000 276,000 167.000 10,000 21.000 412 117,500 70,800 188,300 June 276.000 2,940,000 282,000 40.000 12,000 411 124,200 17,500t 141,700 July 173,000 2,882.000 297,000 14.000 408 125.400 Ol 125,400 Aug. 167,000 2,744.000 304,000 13.000 400 126.700 126.700 Sept. 163,000 2,594.000 282.000 10.000 394 120.000 120,000 Oct. 181,000 2,465,000 278.000 7.000 388 113,400 0, 113,400 Nov. 192,000 2,361,000 264,000 6.000 5,000 384 110,300 2,500 112,800 Dec. Total or average 235,000 2,278,000 273.000 380 109,400 OJ 109,400 5,420,000 3,361.000 337,000 78.000 211.000 381 113,400 12,100i 125,.500 Total for 30-year period, 189ft.1928 188^012,000 97,481,000 37,094,000 2.300,000 40,414,000 10.739,000 Average for 30-year period, 1896-1926 6.267,000 3,249,000 1,236,000 77,000 1,347,000 358,000 393.8 113,400 43,400 156.800 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 281 RESERVOIR ON SACRAMENTO RIVER. MARILY FOR POWER GENERATION WITH INCIDENTAL IRRIGATION FLOOD CONTROL. tions Carried out on a Daily Basis. mary, see Table 4, page 1 14.) Installed capacity of power plant 400,000 k.v.a. P.F. = 0.80. Flood control, liolding maximum space required (454,000 ac. -ft.) in reserve throughout flood season Maximum controlled flow at Red Bluff 125,000 sec.-it. Stage of Power draft Release Average power vieKl reservoir through turbines in through Waste Average in kilowatts Yeir and at acre-feet Evapora- flood over (Load faetor= 3.75) month beginning tion in acre-feet control outlets spillway in power head in feet of month in acre-feet Primary Second- ary in acre-feet acre-feet *Primary Second- ary Total 1923 2,155.000 235,000 380 94,100 94,100 Jan. 2,387,000 218,000 390 98,500 98,500 Feb. 2,466,000 245,000 22,000 392 100,500 9,000 109,500 Mar. 2,486,000 246,000 49,000 7,000 77,000 398 105,300 20,600 125,900 April 2,739,000 270,000 10,000 406 113,300 ■ 113,300 May 2,781,000 276,000 11,000 405 119,700 119,700 .June 2,730,000 290,000 14,000 401 121,100 121,100 July 2,610,000 297,000 12,000 394 122,300 122,300 Aug. 2,466,000 270,000 9,000 388 115,800 115,800 Sept. 2,338,000 272,000 7,000 ■ 382 109,500 109,500 Oct. 2,246,000 259,000 4,000 378 106,500 106,500 Nov. 2,159,000 268.000 372 105,600 105,600 Dec. Total or average 3,152,000 71,000 74,000 77,000 390 109,400 2,500 111,900 1924 2,075,000 240,000 370 94,100 94,100 Jan. 2,038,000 226.000 372 95,100 95,100 Feb. 2,144,000 255,000 374 100,500 100,500 Mar. 2,089,000 261,000 6,000 369 105,300 105,300 April 1,998,000 295,000 8,000 362 113,300 113,300 May 1,850,000 309,000 9,000 352 119,700 119,700 June 1,673,000 334,000 10,000 340 121,100 121,100 July 1,469,000 354,000 8,000 324 122,300 122,300 Aug. 1,247,000 343,000 6,000 306 115,800 115,800 Sept. 1,026,000 357,000 4,000 288 109,500 109,500 Oct. 843,000 351,000 2,000 276 106,500 106,500 Nov. 807,000 367,000 272 105,600 105,600 Dec. Total or average 3,692,000 53,000 334 109,100 109,100 1925 761,000 332,000 268 94,100 94,100 Jan. 730,000 258,000 323 98,500 98,500 Feb. 2,241,000 247,000 54,000 17,000 388 100,.500 21,900 122,400 Mar. 2,486,000 245,000 155,000 7,000 130,000 399 105,300 66,500 171,800 April 2,875,000 268,000 231,000 10,000 408 113,300 96,700 210,000 May 2,840,000 275,000 99,000 12.000 405 119,700 42,900 162,600 June 2,730,000 291,000 14,000 400 121,100 121,100 July 2,598,000 298,000 12,000 394 122,300 122,300 Aug. 2.455,000 276,000 9,000 387 115,800 115,800 Sept. 2.333,000 272,000 7,000 382 109,.500 109,500 Oct. 2,235.000 259,000 5,000 4,000 377 106,500 2,100 108,600 Nov. 2,159,000 269,000 50,000 372 105,600 19,600 125,200 Dec. Total or average 3,290,000 594,000 75,000 147,000 375 109,400 20,900 130.300 Total for 30-year period, 1896-1926 95.438,000 40,980,000 2,208,000 45,734,000 3,652,000 Average for 30-year period, 1896-1926 3,181.000 1,368,000 74,000 1,524,000 122,000 386.9 109,400 47,300 156,700 18—52411 282 WATER RESOURCES OF CALIFORNIA. Height of dam 420 feet. TABLE 5a. KENNETT RESER SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incid jntal irrigation Average power yield in kilowatts (Load facto r=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoirspace month Will Maximum controlled flow require i (454,000 ac .-ft.) in out nooil comroi i at Red Bluff 125,00( sec.-ft. resen-e throughout flood season Maximum reservoir space Maximum controlled flow required 454,000 aore-feet at Red Bluff 125.00C sec.-ft. •Primary Secondary Total •Primary Secondary Total •Primary Secondary Total 1896 Jan. 97,400 40,500 137,900 97,400 47,200 144.600 94.100 52,300 146.400 Feb. 08,400 78,000 176,400 98,400 22,300 120,700 95,100 79.300 174,400 Mar. 104.200 91,100 195,300 104,200 20,400 124,600 100,500 91.400 191,900 April 109,000 101,000 210,000 109,000 101,000 210,000 10o,300 49.000 154,300 May 117,500 92,500 210,000 117,500 92,500 210,000 113,300 96,700 210,000 Jun" 124,200 85,800 210,000 124,200 85,800 210,000 119,700 90,300 210,000 July 125,400 63,700 189,100 125,400 03,700 189,100 121.100 88,900 210,000 Aug. 126,700 42,500 169,200 126,700 42,500 169.200 122,300 81,600 203,900 Sept. 120,000 42,800 162,800 120,000 42,800 162.800 llo,800 41,800 157,600 Oct. 113,400 30,500 143,900 113,400 30,500 143,900 109,500 30,100 139.600 Nov. 110,300 66,800 177,100 If 0,300 66,800 177,100 106,.500 69,700 176,200 Dec 109,400 100,600 210,000 109,400 100,600 210,000 105,600 104,400 210,000 Total or average 113,000 09,500 182,500 113,000 59,700 172,700 109,100 73,000 182,100 1897 Jan. 97,400 55,000 1.52,400 97,400 71,000 168,400 94,100 83,300 177,400 Feb. 101,900 108,100 210,000 101.900 108,100 210,000 98,500 111,500 210,000 Mar. 104,200 105,800 210,000 104,200 53,200 157,400 100,500 107,000 207,500 April 109,000 101,000 210,000 109,000 81,400 190,400 105,300 66,500 171,800 May 117,500 82,500 200,000 117,500 82,500 200,000 113,300 96,700 210,000 June 124,200 32,100 156,300 124,200 32,100 156,300 119,700 90,300 210,000 July 125,400 37,900 163,300 125,400 37,000 163,300 121,100 37,600 158,700 Aug. 126,700 36.200 162,900 126,700 36,200 162,900 122,300 30,200 1.58,500 Sept. 120,000 3>',200 158,200 120,000 38,200 158,200 115.800 37,200 153,000 Oct. 113,400 30,500 143,900 113,400 30,500 143,900 109,-500 30,100 139,600 Nov. 110,300 40,300 150,600 110,300 40,300 150,600 106,500 40,300 140,800 Dec. Total or average 109,400 45,200 154,600 109,400 45,200 154,600 105,600 71,500 177,100 113,400 59,100 172,500 113,400 54,300 167,700 109,400 67.100 176,500 1898 Jan. 97,400 97,400 97,400 97,400 94,100 94,100 Feb. 101,900 101,900 101,900 101,900 98,500 98,500 Mar. 104,200 104,200 104,200 104,200 100,500 100,500 April May 109,000 109,000 109,000 109,000 105,300 105,300 117,500 117,500 117,500 117.500 113,300 113,300 June 124,200 124,200 124,200 124,200 119,700 119,700 July 125.400 125,400 125,400 125,400 121,100 121,100 AUR. 120,700 126,700 126.700 126,700 122,300 122,300 Sept. 120,000 120,000 120,000 120,000 115,800 115,800 Oct. 113,400 113,400 113,400 113,400 109,500 109,500 Nov. 110.300 8,800 119,100 110,300 8,800 119,100 106,500 5.300 111,800 Dec. Total or avoraKc 109.400 109,400 109,400 109.400 105,600 13.000 118,600 113,400 700 114,100 113.400 700 114.100 109,400 1.500 110,900 1899 Jan. 97,400 97,400 97,400 18,400 115.800 94,100 94,100 Feb. 101,900 101,900 101,900 101,900 98,500 98,500 Mar. 10t,200 27.300 131,500 104,200 23,900 128,100 100,500 85.900 186,400 April May 109.000 76.300 185,300 109,000 61,500 170,500 105,300 24,400 129.700 117,500 18.800 136,300 117,500 18,800 136,300 113,300 113,300 June 124.200 25,700 149,900 124,200 25,700 149,900 119,700 119,700 July 125,400 23,100 148,500 125,400 23,100 148,500 121,100 121,100 Auk. 126,700 21,200 150,900 126,700 21,200 150,900 122,300 23,400 145,700 Sept. 120,000 10,900 136,900 120.000 16,900 136,900 115,800 16,800 132,600 Oct. 113,400 26,500 139,000 113,400 20,500 139,900 109,500 26,100 135,600 Nov. 110,300 77.900 188,200 110,300 77.900 188,200 106,500 80.700 187,200 Deo. Total or average 109,400 100,600 210.000 109,400 100.600 210,000 105,600 104.400 210,000 113,400 34,900 148,300 113.400 35.000 148,400 109,400 30,400 139,800 *Total primary power productioD in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 283 VOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL. la, 2a and 4a. mary, see Table 5, page 1 16.) Installed capacity of power plant 400,000 k.v.a. P.P. =0.80. Operating primarily for irrigation witli incidental power generation Seasonal irrigation yield 4,276.000 acre-feet. (Deficiency in supply one year in ten, no deduction for downstream prior rights). Average power yield in kilowatts (Load factor^!. 00) Coordinated with flood control by reservoir operating diagram Year and Without flood control Maximum controlled flow at Red Bluff 125,000 sec.-ft. month Maximum reservoir space required 454,000 acre- Feet Primary Secondary Total Primary Secondary Total 1896 89,900 89,900 99,100 99,100 Jan. 199,400 199,400 104,000 104,000 Feb. 225,300 225,300 134,900 134,900 Mar. 275,800 275,800 275,800 275,800 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 .Tune 280,000 280,000 280,000 280,000 •luly 280,000 280,000 280,000 280,000 Aug. 176,100 176,100 176,100 176,100 Sept. 56,200 56,200 56,200 56,200 Oct. Nov, Dec. Total or 178,400 178,400 164,000 164,000 average 1897 59,800 59,800 195,700 195,700 Jan. 280,000 280,000 276,000 276,000 Feb. 254.600 254,600 171,600 171,600 Mar. 280,000 280,000 242,100 242.100 April 280,000 280,000 280,000 280.000 May 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 264,400 264,400 264,400 264,400 Aug. 152,400 152,400 152,400 152,400 Sept. 48,000 48,000 48,000 48,000 Oct. Nov. Dec. Total or average 180,800 180,800 181,900 181,900 1898 Jan. Feb. 17,300 17,300 17,300 17,300 Mar. 91,000 91,000 91,000 91,000 April 275,000 275,000 275,000 275,000 May 280,000 280,000 280,000 28,000 June 260,200 260,200 260,200 260,200 July 162,000 162,000 162,000 102,000 A.ig. Sept. Oct. Nov. Dec. Tnf al nr 91,200 91,200 91,200 91,200 average 1899 Jan. Feb. 15,900 15,900 15,900 15,900 Mar. 89,300 89,300 89,300 89,300 April 272,400 272,400 272,400 272,400 May 280,000 280,000 280,000 280,000 June 252,000 252,000 252,000 2.52,000 July 146,100 146,100 146,100 146,100 Aug. Sept. Oct. Nov. Dec. Total or average 88,700 88,700 88.700 88,700 2«4 WATER RESOURCES OF CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigation Average power yield in kilowatts (Load factor=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoir space month Wit! out flooil CO , . Maximum oontroll d flow require i (454,000 ac .-ft.) in at Red Bluff 125,00C sec.-ft. reserve throughout flood season Maximum reservoir space Maximum controlled flow required 454,000 acre-feet at Red Bluff 125,00C sec.-ft. 'Primary Secondary Total ♦Primary Secondary Total ♦Primary Secondary Total 1900 Jan. 97.400 103,500 200,900 97,400 110,900 208,300 04,100 112,900 207.000 Feb. 101.900 62,500 164,400 101,900 22,000 123,900 98,500 64,900 163.400 Mar. 104,200 102,400 206,600 104,200 43,800 148,000 100,500 104.200 204.700 April 109,000 80,300 189,300 109,000 33,900 142,900 105,300 20,700 126.000 May 117,500 46,600 164,100 117,500 46,000 164,100 113,300 113,300 June 124,200 4,900 129,100 124,200 4,900 129,100 119,700 119,700 July 125,400 14,800 140,200 125,400 14,800 140,200 121,100 14,700 135,800 Aug. 126.700 17,900 144,600 126,700 17,900 144,600 122,300 18,100 140,400 Sept. 120,000 18,800 138,800 120,000 18,800 138,800 115,800 18.500 134.300 Oct. 113,400 49,200 162,600 113,400 49,200 162,600 109,500 48,.500 158,000 Nov. 110,300 59,700 170,000 110,309 59,700 170,000 106,500 61,900 168,400 Dec. Total or average 109.400 89,000 198,400 109,400 89,000 198,400 105,600 99,200 204.800 113,400 54,200 167,600 113,400 42,900 156,300 109,400 47,100 156,500 1901 Jan. 97,400 3',),90O 137,300 97,400 101,600 199,000 94,100 115,900 210,C0D Feb. 101,900 101.200 206,100 101,900 99,400 201,300 98,500 105.830 205,300 Mar. 104,200 103,800 208,000 101,200 52,400 156,600 100,500 108,000 20l).500 April 109.000 51,000 163,000 109,000 109,000 105,300 15,40) 120,700 May 117,500 51,100 168,600 117,500 28,500 1 16,009 113,300 113,300 June 124,200 1,800 126,000 121,200 1.800 126,000 119.700 119.700 July 125,400 14,200 139,600 125,400 14.200 131,600 121.100 121,100 Aug. 126,700 17.100 143.800 120,700 17,100 143,800 122.300 122.300 Sept. 120.000 18.200 1.38.200 120.000 18,200 138,200 115,800 20,600 136,400 Oct. 113,400 11,400 121.800 113.100 11,400 124,800 109,500 ii,3no 12;),800 Nov. 110.300 42.5')0 152 800 110,300 42,500 152,800 106,509 43,300 149,800 Dec. Tntil nr 109,400 1 13 ,400 100,600 210,000 109,400 100,600 210,000 105,600 101,403 210,000 average 40.300 159,700 113.400 40,400 1,53,800 109,400 43,400 152,800 1902 Jan. 97,400 97,400 97,100 97,400 94,100 94,100 Feb. 101,900 69,300 171,2(10 101,900 77,100 179,000 98,500 79.800 178,300 Mar. 101,200 105,800 210,001) 101.200 75,300 179,500 100,,500 109,500 210.000 April 109,000 101.000 210,000 109,000 81.500 190,500 105,300 73,500 178,800 May 117,,500 91.400 208.900 117,.500 91.400 208,900 113,300 96.700 210,000 June 124.200 71,700 195,900 121,200 71.700 195,900 119,700 90,300 210,000 July 125 400 29,000 151,400 125,400 29,000 151,400 121.100 78.800 199.900 Aug. 126,700 28,400 1.55,100 126,700 28,400 155,100 122,300 27.800 150.100 Sept. 120.000 11,400 131,400 120,000 11,400 131,400 115,800 11.400 127.200 Oct. 113,400 19,.500 132,900 113,400 19,500 132,900 109,500 19,200 128,700 Nov. 110,300 81.100 191,400 1 10,300 81,100 191,400 106,500 81,300 190,800 Dec. Tntjil nr 109,400 100,000 210,000 109,400 100,600 210,000 105,600 101.400 210.000 A UbUI Ul average 113,400 58,900 172,300 113,400 55,300 168,700 109,400 64.500 173,900 1903 Jan. 97,400 90,300 187,700 97,400 106,900 201, .300 94.100 89,500 183,600 Feb. 101,900 108,100 210,000 101,900 100,100 202,000 98,500 111,500 210,000 Mar. 104.200 105,800 210.000 10-1,200 99,600 203,800 100,500 109.500 210,000 April May 109,000 101,000 210,000 109,000 98,100 207,100 105,300 41.900 147,200 117,.500 64,700 182.200 11 7. ,500 64,700 182,200 113.300 60.600 173,900 June 124,200 18,300 142.500 121.200 18,.300 142,500 119.700 18,600 138.300 July 125.400 19.800 145.200 125,400 19,800 145,200 121,100 19,600 140.700 Aug. 126,700 16.300 143,000 126,700 16.300 143.000 122,300 16.500 1.38.800 Sept. 120.000 7,200 127.200 120,000 7,200 127,200 115,800 7.100 122,900 Oct. 113,400 4,800 118.200 113,400 4.800 118,200 109,500 4.800 114,300 Nov. 1 10.300 65.600 175,900 110,300 65.600 175.900 106.500 68.200 174.700 Dec. Total or 109,400 100,600 210,000 109,400 95,300 201,700 105,600 104,400 210,000 average 113,400 58,200 171,600 113,400 57,800 171,200 109,400 51,100 163,500 *Total primary power production in February of leap years taken the same as in other years. THE CONTROL OP FLOODS BY RESERVOIRS. 285 RESERVOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL. la, 2a and 4a. mary, see Table 5, page 116.) Installed capacity of power plant 400,000 k.v.a. P.F. =0.80. — Operating primarily for irrigation with incidental power generation 1 Seasonal irrigation yield 4,276,000 acre-feet. (Deficiency in supply one year in ten, | no deduction for downstream prior rights). Average power yield in kilowatts (Load factor=1.00) Coordinated with flood control by reservoir operating diagram Year and Without flood control Maximum controlled flow at Red Bluff 125,000 sec.-ft. month Maximum reservoir space required 454,000 acre-feet Primary Secondary Total Primary Secondary Total 1900 73,800 73,800 JaD. 57,300 57,300 125,100 125,100 Feb. (1 247,400 247,400 137,400 137,400 Mar. 197,800 197,800 170,600 170,600 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 232,500 233,500 232,500 232,500 Aug. n 124,400 124,400 124,400 124,400 Sept. 38,200 38,200 38,200 o8,200 Oct. Nov. Dec. Total or 145,500 145,500 145,300 145,300 a\ erage 1901 Jan. 89,700 89,700 214,700 214,700 Feb. 248,800 218,800 159,100 159,100 Mar. 165,000 165,000 105,000 105,000 April 280,000 280,000 280,009 280,000 May 280,000 280,000 280,000 280,000 June 280.000 280,000 280,030 280,000 July 230,900 230,900 230,900 230,900 Aug. 1) 123,100 123,100 123,100 123,100 Sept. (1 35,900 35.900 35,900 35,900 Oct. 1) Nov. Dec Total or 144,900 144,900 142,000 142,000 average 1902 Jan. 110.100 110,100 149,600 149,600 Feb. 273,700 273,700 218,000 218.000 Mar. 277.200 277,200 241,500 241.500 April 280,000 280,000 280,000 280.000 May 280,000 280,000 280,000 280,000 June II 280.000 280,000 280,000 280.000 July II 280,000 280,000 280,000 280.000 Aug. II 160,600 160,600 160,600 160.600 Sept. n 50,000 50,000 50.000 50,000 Oct. I) Nov Dec. Total or average 166,300 166,300 161,600 161,600 1903 II 63,000 63,000 178,800 178.800 Jan. 1) 265,500 265.500 237,600 237,600 Feb. II 280,000 280,000 252,000 252.000 Mar. 266.400 266,400 253,900 253.900 April 280,000 280.000 280,000 280,000 May II 280.000 280.000 280,000 280,000 June II 280.000 280,000 280,000 280,000 July 212.700 242.700 242,700 212.700 Aug. 131,700 131.700 131,700 131.700 Sept. 38,300 38,300 38,300 38,300 Oct. Nov. Dec. 1 Total or average 176,700 176,700 181,000 181,000 286 WATER RESOURCES OF CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigation Average power yield in kilowatts (Load factor=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoir space month \\^it,b"iit fl""'' «nn(rnl Maximum controlled flow required (454,000 ac .-ft.) in at Red Bluff 125,00C sec.-ft. reserve tl: roughout flood season Maximum reservoir space Maximum controlled flow required 454,000 acre-feet at Red Bluff 125,000 sec-ft. •Primary Secondary Total •Primary Secondary Total ♦Primary Secondary Total 1904 Jan. 97.400 80,000 177,400 97,400 94,500 191.900 94,100 82,300 176,400 Feb. 98.400 92,400 190,800 98,400 70,500 168,900 95,100 89,400 184.500 Mar. 101.200 105 800 210,000 104,200 105,800 210,000 100.500 109.500 210.000 April 109,000 101.000 210,000 109,000 101,000 210,000 105,-300 84.000 189,300 May 117,.500 92.500 210,000 117,500 92.500 210,000 113,.300 96,700 210.000 .Tunc 124.200 85,800 210,000 124,200 85,800 210,000 119,700 90,300 210,000 .July 12,5,400 84,600 210,000 125,400 84,600 210,000 121.100 88.900 210.000 AuE 126.700 54,600 181,300 126.700 54,600 181,300 122..300 87,700 210,009 Sept. 120,000 48,300 168.300 120.000 48,300 168,300 115.800 74.600 190.400 Oct. 113,400 81,900 195.300 113,400 81,900 I95,.300 109,500 100,500 210,000 Nov. 110,300 99,700 210.000 110,,300 99,700 210.000 105,500 101.500 208,000 Dec. 109,400 100,600 210,000 109,400 100.600 210,000 105,600 101.500 207.100 Total or average 113.000 85,600 198,600 113,000 85,100 198,100 103,100 92,300 201,400 1905 Jan. 07,400 36,300 133,700 97,400 72,600 170,000 91,100 63.600 157,700 Feb. 101,900 108,100 210,000 101,900 103,600 205,500 98,500 111,500 210,000 Mar. 104.200 105,800 210,000 104,200 98,400 202,600 100,500 109,500 210.000 April 109,000 101,000 210.000 109,000 101,000 210,000 105,303 45,600 150,900 May 117,.500 87,600 205.100 117,500 87,600 205.100 113,.3O0 88.200 201,500 June 124,200 56,100 180,300 124,200 56.100 180.300 119,700 73,800 193.500 July 12.5,400 35,500 160,900 125,400 35.500 160,900 121,100 34.900 15S.OO0 Aug. 126,700 29,200 155,900 126.700 29,200 1.55.900 122,300 28,800 151,100 Sept. 120 000 21.700 141,700 120,000 21,700 141,700 115.800 21.400 137.200 Oct. 113 400 13,800 127,200 113,400 13,800 127,200 109.500 13.700 123.200 Nov. 110,300 21,900 132,200 110.300 21,900 132,200 106,500 21,800 128,300 Dec. Total or 109.400 109,400 109,400 109.400 105,600 25,500 131,100 average 113,400 51,000 164,400 113.400 .53,100 166.500 109,400 52,800 162,200 1906 .Ian. 97,400 97,400 97,400 21,600 119,000 94,100 44,400 138.500 Fob. 101,900 64,700 166.600 101,900 63,700 165,600 98,500 95,800 194.300 Mar. 104,200 105,800 210,000 104,200 98,900 203,100 100,500 109,500 210,000 April May 109,000 101,000 210,000 109,000 101,000 210,000 105,300 61,500 166,800 117,500 92,500 210,000 117,500 92,500 210.000 113,300 96,700 210,000 June 124,200 85,800 210,000 124,200 85,800 210.000 119,700 90,300 210.000 July 125,400 84,600 210,000 125,400 84,600 210,000 121,100 88,900 210,000 Aug. 126.700 61.700 188.400 126,700 61,700 188,400 122,300 87,700 210,000 Sept. 120,000 37,800 157.800 120.000 37,800 157.800 115,800 72,200 188,000 Oct. 113,400 26.100 139.500 113,400 26,100 139,500 109,500 25,700 135.200 Nov. 110,300 32,800 143.100 110,300 32,800 143,100 106,500 32.900 139,400 Deo. Total or 109,400 74.300 183,700 109,400 74,300 183,700 105,600 84,700 190,300 average 113,400 63,900 177,300 113,400 65,100 178,500 109,400 74,100 183,500 1907 Jan. 97,400 18,500 115,900 97,400 100,300 197,700 94,100 100.900 195,000 I'eb. 101,900 108,100 210,000 101,900 108,100 210.000 98,500 111,500 210,000 Mar. 104,200 105,800 210,000 104,200 105,800 210,000 100,500 109,500 210,000 April May 109,000 101,000 210,000 109,000 101,000 210,000 105,300 84,000 189,300 117,500 92,500 210,000 117,500 92,.500 210.000 113,300 96,700 210.000 June 124.200 78,200 202,400 124,200 78,200 202,400 119.700 90,300 210.000 July 125,400 62.600 188,000 125,400 62,600 188,000 121,100 88.900 210.000 Aug. 126,700 52,000 178,700 126,700 52,000 178,700 122,300 83,600 205.900 Sept. 120,000 40,300 160,300 120,000 40,300 160,300 115.800 39,300 155,100 Oct. 11.3,400 30,100 143.500 11.3,400 30,100 143,500 109,500 29,700 139.200 Nov. 110,300 33,300 143,600 110,300 33,300 143,600 106,500 32,900 139.400 Dec. Total or 109.400 55,100 164,500 109,400 55,100 164,500 105,600 76,200 181,800 average 113,400 64,500 177.900 113,400 71,400 184,800 109,400 78,500 187.900 •Total primary power production in February of leap years taken the same as in other years. TPIE CONTROL OF FLOODS BY RESERVOIRS. 287 RESERVOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL, la, 2a and 4a. mary, see Table 5, page 1 16.) Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Operating primarily for irrigation with incidental power generation Ssasonal irrigation yield 4,276,000 aore-feet. (Defioiency in supply one year in ten. no dsluotion for downstream prior rights). Average power yield in kilowatts (Load factor^l.OO) Coordinated with flood control by reservoir operating d agram Year and Without flood control Maximum controlled flow at Red Bluff 125,000 sec.-ft. month Maximum reservoir space required 454,000 acre- feet Primary Secondary Total Primary Secondary Total 1904 Jan. 125,100 125,100 155,300 155,300 Feb. 280,000 280,000 280,000 280,000 Mar. n 280,000 280,000 280,000 280,000 April 280,000 280,000 280,000 280,000 May n 280,000 280,000 (1 280,000 280,000 June n 280,000 280,000 280,000 280,000 July 280,000 280,000 280,000 280,000 Aug. 178,300 178,300 178,.300 178,300 Sept. n 58,000 ."8,000 58,600 58,600 Oct. Nov. Dec. Total or 170,200 170,200 172,600 172,600 average 1905 132,100 132,100 222.700 222,700 Jan. 278,300 278,300 268,600 268,600 Feb. 273,500 273,500 250,900 250,900 Mar. 270,800 270,800 270.800 270,800 April n 280,000 280,000 280,000 280,000 May 280.000 280,000 280,000 280.000 June 280,000 280,000 280,000 280,000 July 270,200 270,200 270,200 270,200 Aug. 153,800 153,800 153,800 153,800 Sept. n ■17,600 47.600 47,600 47,600 Oct. Nov. Dec. Total or 188,300 188,300 193,300 193,300 average 1906 Jan. n 53,300 53,300 Feb. 280,000 280,000 257,900 257,900 Mar. 280,000 280,000 280,000 280,000 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July n 280,000 280,000 280,000 280,000 Aug. 186,000 186,000 186,000 186,000 Sept. 59,300 59,300 59,300 59,300 Oct. Nov. Dec. Total or 161,500 161,500 163,700 163,700 average 1907 59,100 59,100 219,600 219,600 .Ian. 280,000 280,000 280,000 280,000 Feb. 280,000 280,000 278,600 278,600 Mar. • 280,000 280,000 280,000 280,000 April 280,000 280,000 280,000 280,000 May n 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July (1 280,000 280,000 280,000 280,000 Aug. 169,700 169,700 169,700 169,700 Sept. n 53,900 53,000 53,900 53,900 Oct. Nov. Dec. Total or average 186,200 186,200 199,700 199,700 288 WATER RESOURCES OP CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigation Average power yield in kilowatts (Load facto r=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoir space month Tir:*i ,.A a^ 1 ..»n4.-»1 Maximum controlled flow required (454,000 a( .-ft.) in witr """ """" ''W UllUl at Red Bluff 125,000 sec.-ft. reserve throughout flood season Maximum reservoir space Maximum controlled flow required 454,000 acre-feet at Red Bluff 125,000 sec.-ft. •Primary Secondary Total •Primary Secondary Total •Primary Secondary Total 1908 Jan. 97,400 20,200 117,600 97,400 38,300 135,700 94,100 48,500 142,600 Feb. 98,400 111,600 210,000 98,400 90,800 189,200 95,100 111,600 206,700 Mar. 104.200 105,800 210,000 104,200 36,300 140,500 100,500 109,400 209,900 April 109,000 98,100 207,100 109,000 58 300 167,300 105,300 20,700 126,000 May m.hoo 79,600 197,100 117,500 79,600 197,100 113,300 59,000 172,300 June 124,200 45,100 169,.300 124.200 45,100 169,300 119,700 45,100 164,800 July 125,400 31,600 157,000 125,400 31,600 157,000 121,100 31.200 1.52,300 Aug. 126,700 26,200 152,900 126,700 26,200 152,900 122.300 25,900 148.200 Sept. 120,000 20,400 140,400 120,000 20.400 140,400 115,800 20.100 135,900 Oct. 113,400 19,500 132,900 113,400 19.500 132,900 109,500 19,200 128,700 Nov. 110,300 33,800 144,100 110,300 33,800 144,100 106,500 33,300 139,800 Dec. 109.400 5,900 115,300 109,400 5,900 115,300 105,600 32,300 137,900 1 U 1.11 Vl average 113,000 49,500 162,500 113,000 40,200 153,200 109,100 46,200 155,300 1909 Jan. 97,400 76,200 173,600 97.400 87,100 184,500 94,100 89,700 183,800 Feb. 101,900 108,100 210,000 101,900 108,100 210,000 98.500 111,500 210,000 Mar 104,200 105,800 210,000 104,200 81,700 185,900 100,500 109,500 210,000 April 109,000 101,000 210,000 109,000 100,100 209,100 105,300 52,500 157,800 May 117.500 91,.500 209,000 117.500 91,500 209,000 113,300 96,700 210,000 June 124,200 74,900 199,100 124,200 74,900 199,100 119,700 90,300 210,000 July 125,400 51,700 177,100 125,400 51,700 177,100 121,100 70,800 191,900 Aug. 120,700 40,900 167,600 120,700 40.900 167,600 122,300 40,300 162.600 Sept. 120,000 37,800 157,800 120,000 37,800 157,800 115,800 36,800 152,600 Oct. 113,400 39,400 152,800 113.400 39,400 152,800 109,500 38.400 147.900 Nov. 110,300 72,500 182,800 110,300 72,500 182,800 106,500 73,600 180,100 Dec. Total or average 109,400 100,000 210,000 109,400 100,600 210,000 105,600 104,400 210,000 113,400 74,800 188,200 113,400 73,600 187,000 109,400 76,100 185,500 1910 Jan. 97,400 29,000 126,400 97,400 57,000 154,400 94,100 93.800 187,900 Feb. 101,900 108,100 210.000 101,900 62,900 164,800 98,500 111,500 210,000 Mar. 104,200 105,800 210.000 104.200 100,400 204,600 100,500 109,500 210,000 April 109,000 101,000 210,000 109.000 101,000 210,000 105,300 38,800 144,100 May 117,500 .54,400 171,900 117,500 54,400 171,900 113,300 39,400 152,700 Juno 124,200 20,100 144.300 124,200 20,100 144,300 119,700 20,400 140,100 July 125,400 29,400 154,800 125,400 29,400 154,800 121,100 20,200 150,300 Aug. 126,700 29,200 155,900 126,700 29,200 1,55,900 122.300 28,800 151,100 Sept. 120,000 24,200 144,200 120,000 24,200 144,200 115,800 23,<)O0 139,700 Oct. 113,400 17,900 131,300 11.3.400 17,900 131,300 109,500 17,700 127,200 Nov. 110,300 40,300 150,600 110,300 40.300 150,600 106,.500 40,300 146,800 Dec. Total or 109.400 73.400 182,800 109,400 73,000 182,400 105,600 98,500 204,100 average 113,400 52.300 165,700 113,400 50,800 164,200 109.400 54,100 163,500 1911 Jan. 97,400 97.400 97,400 7,300 104.700 94,100 3,800 97,900 Feb. 101.900 88,100 190,000 101,900 75.000 176,900 98,500 111,500 210.000 Mar. 104,200 104,400 208.600 101,200 100,900 205,100 100.500 107.700 208.200 April May 109,000 101,000 210,000 109,000 101.000 210,000 105,300 70,000 175,300 117,.500 92.500 210.000 117,500 92.500 210,000 113,300 96,700 210,000 June 124.200 79,600 203.800 124.200 79,600 203,800 119,700 90.300 210,000 July 125,400 42.900 168,300 125,400 42,900 168,300 121,100 88,900 210,000 Aug. 126,700 32.500 1.59.200 126.700 32,500 159,200 122,300 43,500 165,800 Sept. 120,000 30.700 150.700 120,000 30,700 150,700 115,800 30.600 146,400 Got. 113,400 24.100 137.500 113,400 24 100 137,500 109,500 23,700 133,200 Nov. 110,300 26,900 137,200 110,300 26,900 137,200 106.500 28,700 133.200 Dec. Total or 109.400 109,400 109,400 109,400 105,600 23,300 128,900 average 113,400 51,500 164,900 113,400 50.800 164,200 109.400 59,300 168,700 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 289 RESERVOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL, la, 2a and 4a. mary, see Table 5, page 1 16.) Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Operating primarily for irrigation with incidental power generation Seasonal irrigation yield 4,276,000 acre-feet. (Deficiency in supply one year in ten, no deduction for downstream prior rights). Average power yield in kilowatts (Load factor=1.00) Coordinated with flood control by reservoir operating diagram Year and Without flood control Maximum controlled flow at Red Bluff 125,000 sec.-ft. month Maximum reservoir space required 454,000 acre- feet Primary Secondary Total Primary Secondary Total 1908 18,100 18,100 Jan. 213,100 213,100 232,200 232,200 Feb. 264,300 264,300 128,900 128,900 Mar. 227,900 227,900 207,800 207,800 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 258,500 258,500 258,500 2.58,500 Aug. 146,000 146,000 146,000 146,000 Sept. 44,800 44,800 44,800 44,800 Oct. Nov. Dec. Total or average 166,000 166,000 155,900 155,900 1909 117,100 117,100 128,600 128,600 Jan. 280,000 280,000 280,000 280,000 Feb. 280,000 280,000 225,800 225,800 Mar. 280,000 280,000 275,300 275,300 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 280,000 280,000 280,000 280.000 Aug. 163,100 163,100 163,100 163,100 Sept. 51,700 51,700 51,700 51,700 Oct. Nov. Dec. Total or average 190,400 190,400 186,400 186,400 1910 63,200 63,200 Jan. 257,400 257,400 190,300 190.300 Feb. 280,000 280,000 265,700 265,700 Mar. 264,900 264,900 264,900 264,900 April 280,000 280,000 280,000 280,000 May 280.000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 242,600 242,600 242,600 242,600 Aug. 135,400 135,400 135,400 135,400 Sept. n 41,000 41,000 41,000 41,000 Oct. Nov. Dec. Total or average 171,100 171,100 170,100 170,100 1911 Jan. (1 75,600 75,600 Feb. 237,000 237,000 263,200 263,200 Mar. 280,000 280,000 278,300 278,300 April 280,000 280,000 280,000 280,000 May 280.000 280.000 280,000 280,000 June 280.000 280,000 280,000 280,000 July 280,000 280,000 280.000 280,000 Aug. 165,600 165,600 165,600 165,600 Sept. 52,300 52,300 52,300 52,300 Oct. Nov. Dec. Total or average 155,500 155,500 163,400 163,400 290 WATER RESOURCES OF CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigation Average power yield in kilowatts (Load factor=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operatinE diagram maximum reservoir space month WTii L...1 n_-j ._ ntrol Maximum controlled flow require d (454,000 a( .-ft.) in Wltuuui uuuu uu at Red Bluff 125,000 sec.-ft. reserve throughout flood season Maximum reservoir space Ma.iiimum controlled flow required 454,000 acre-feet at Red Bluff 125.000 sec.-ft. •Primary Secondary Total ♦Primary Secondary Total •Primary Secondary Total 1912 Jan. 97,400 97,400 97.400 97,400 94,100 94,100 Feb. 98,400 98.400 98.400 98.400 95,100 17,701 112,800 Mar. 104,200 50.300 151. .500 104,200 50,300 151.500 100.500 109,500 210.000 April 109.000 80,000 189.000 109,000 80,000 189 000 105.300 15.100 120,700 May 117,500 91,900 209,400 117,500 91,900 209,400 ]1.3,.300 87.100 200,400 June 124.200 09,000 193.200 124.200 69,000 193,200 119,700 90.300 210,000 July 125,400 37.500 162 900 125,400 37.500 162,900 121,100 76.300 197.400 Aug 126,700 30 000 156.700 126.700 30.000 156.700 122,300 29.600 151.900 Sept. 120.000 36.000 156.000 120,000 36.000 156,000 115.800 35.100 150,900 Oct. 113.400 15,900 129,300 113,400 15.900 129,300 101.501 15,600 125.100 Nov. 110..300 87,100 197,400 1 10.300 87,100 197.400 106,500 90.100 196.600 Dec. 109.400 64,500 173,900 109,400 64,500 173.900 105.600 85.800 191,400 Total or average 113,000 46,900 159,900 113,000 46,900 159,900 109,100 51..500 163,600 1913 Jan. 97,400 97,400 97.400 45,000 142.400 94.100 39.800 133,900 Feb. 101,900 6,400 108.300 101,900 7,600 109.500 98,500 76.310 174.800 Mar. 104,200 76,200 180,400 104,200 104.200 100.500 80.100 180,600 April May 1 09.000 10 ',000 210,000 109,000 87,600 196.600 105.300 41.100 146.400 117.500 85.500 203,000 117,500 85.500 203.000 113,300 89,000 202,300 June 124,200 36,800 161.000 124,200 36,800 161,000 119,700 36.800 156.500 July 125,400 32,800 158,200 125,400 32.800 158,200 121,100 32.900 154.000 Aug. 126,700 27.600 151,309 126.700 27.600 154,300 122,.300 27.200 149.500 Sept. 120,000 14 000 134,000 120;000 14.000 134,000 115.800 13.900 129.700 Oct. 113.400 6.000 119,400 113,400 6.000 119,400 109.500 6.000 115,500 Nov. 1I0..300 43,600 153,900 110,300 43,600 153,900 106,500 43.800 150,.300 Dec. Total or average 109,400 72,900 182,300 109.400 72,900 182,300 105,600 90,500 196,100 113,400 42,100 I.55,.500 11.3,400 38,500 151,900 109.400 48,000 157,400 1914 Jan. 97,400 105,500 202,900 97,400 105,200 202,600 94.100 1 15,P00 210.000 Feb. 101,900 108,100 210.0110 101,900 108,100 210.000 98.500 111,500 210,000 Mar. n 1.200 1()").S0() 2io.o:io 101,200 99,600 203,800 100.500 101.500 210.000 April 100.000 101.000 210.000 lO't.OOO 100,700 209.700 105,300 81,800 187.100 May 117,500 92.500 210,000 117,500 92.500 210,000 113,300 96.700 210.001 .Tunc 124200 85.800 210.000 124,200 85,800 210.000 119,700 90.300 210.000 July 125,400 51.800 180,200 125.400 51,800 180.200 121.100 88.900 210.000 Aug. 126,700 .34.100 160.800 126,700 34,100 160.800 122.300 68,400 190.700 Sept. 120,000 28.800 148,800 120,000 28,800 148.800 115,800 28.500 141..300 Oct. 113.400 33.2C0 146,600 113.400 33,200 146.600 101.500 32.900 142.400 Nov. 110,300 31,100 141,401 1 10,301 31,100 141.400 lOfi.500 31. .300 137.800 Dec. Total or average 109,400 113.400 37.900 147,301 109,400 37.900 •147.300 105.600 63.700 169,300 68,000 181,400 113,400 67,400 180.800 103.400 76.500 185.900 1016 Jan. 97.400 97,400 97,400 40.901 138.300 94,100 14.f01 109.000 Feb. 101,900 108,100 210,000 101,900 108.100 210.000 98.500 111, .500 210.000 Mar. 101,200 105.800 210,000 101,200 105,800 210 000 100.500 109.501 210,000 April May 109.000 101,000 210,000 109,010 101,000 210.011 105.300 76,800 182,100 117,500 92.501 210.000 117,500 92.501 210.000 113,300 96.700 210,000 June 121,200 85,800 210.000 121.200 85.800 210.010 119 700 90,300 210.000 July 125.409 83.900 20t.300 125.401 83,900 20'l.301 121,100 88.Q01 210.000 Aug. 126,700 41.701 168,400 126,701 41,700 1 68.401 122 301 87,700 210,000 Sept. 120.001 24.701 141,701 120,000 21.700 141,700 1 15,800 44,901 160.701 Oct. 11.3.100 18.701 132.101 113.400 18.700 132,100 109.500 18,400 127.900 Nov. 110.300 32.401 1 42,700 1 10.300 32.400 142,700 106,500 32,101 1.38,600 Dec. Total or 109.400 94,900 201,300 109.400 94.900 204,300 105.600 100,100 205,700 average 113.400 65,500 178.900 113.') 00 69.000 182,400 109,400 72,400 181.800 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OF FLOODS BY RESERVOIRS. 291 RESERVOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL, la, 2a and 4a. mary, see Table 5, page 116.) Installed capacity of power plant 400,000 k.v.a. P.P. =0.80. Operating primarily for irrigation with incidental power generation Seasonal irrigation yield 4,276.000 acre-feet. (Deficiency in supply one year in ten, no deduction for downstream prior rights). Average power yield in kilowatts (Load factor=1.00) Coordinated with flood control by reservoir operating diagram Year and Without flood control ■ Maximum controlled flow at Red Bluff 125,000 sec.-ft. month Maximum reservoir space required 454,000 acre- feet Primary Secondary Total Primary Secondary Total 1912 Jan. Feb. 23,000 23,000 23,000 23,000 Mar. 1M,900 199,900 199.900 199,900 April 280,000 280,000 280,000 280,000 May 280,000 280,000 280,000 280,000 June n 280,000 280,000 280,000 280,000 July 280,000 280.000 280,000 280,000 Aug. 163,600 163.600 163,600 163,600 Sept. 51,500 51,500 51,500 51,500 Oct. Nov. Dec. Total or 130,200 130.200 130,200 130,200 average 1913 Jan. 62,500 62,500 Feb. 150,400 150,400 91,500 91.500 Mar. 274,300 274,300 274,300 274,300 April 280,000 280.000 280,000 280,003 May 280,000 280,000 280.000 280,000 June 280,000 280,000 280,000 280.000 July 260,400 260,400 260,400 260.400 Aug. 146,500 146,500 146,500 146.500 Sept. 4^,500 44,500 44,500 44,500 Oct. Nov. Dec. Total or average 143,800 143,800 143,600 143,600 1914 144,100 144,100 171,100 171,100 Jan. 275,700 275 700 280.000 280.000 Feb. 280,000 280,000 255,800 255,800 Mar. 278,600 278,600 273,200 273,200 April 280,000 280,000 280.000 280,000 May 280,000 280,000 280.000 280,000 June 280,000 280,000 280,000 280.000 July 280,000 280,000 280.000 280.000 Aug. 168,300 168.300 168.300 168.300 Sept. 53,400 53,400 53,400 53,400 Oct. Nov. Dec. Total or average 192,800 192,800 192,900 192,900 1915 9,000 9,000 Jan. 269.200 269,200 278,100 278.100 Feb. 280,000 280,000 271,900 271,900 Mar. 280,000 280,000 280,000 280,000 April 280,000 280,000 280.000 280,000 May 280,000 280,000 280,000 280,000 Jane 280,000 280,000 280,000 280.000 July 280,000 280,000 280,000 280,000 Aug. 177.500 177.500 177,500 177.500 Sept. 56,000 56,000 56,000 56,000 Oct. Nov. Dec. Total or average 181,100 181,100 181.900 181,900 292 WATER RESOURCES OF CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with Incidental Irrigation Average power yield in kilowatts (Load factor =0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoir space month Without flood control Maximum controlled flow at Red Bluff 125.000 sec.-ft. required (454,000 ac.-ft.) in reserve throughout flood season Maximum reservoir space Maximum controlled flow required 454,000 acre-feet at Red Bluff 125,000 sec.-ft. •Primary Secondary Total •Primary Secondary Total •Primary Secondary Total 1916 Jan. 97,400 32,700 130,100 97,400 90,700 188,100 94,100 85,900 180,000 Feb. 98,400 111,600 210,000 98.400 107,900 206,300 95,100 111,600 206,700 Mar. 104,200 105,800 210,000 104.200 97.000 201.200 100,500 109,500 210,000 April 109,000 100,300 209,300 109,000 92,400 201,400 105,300 41,900 147,200 May 117,500 73,500 191,000 117.500 73,500 191,000 113,300 73,400 186,700 June 124,200 50,800 175,000 124,200 50,800 175,000 119,700 50,700 170,400 July 125,400 55,200 180,600 125,400 55,200 180,600 121,100 54,600 175,700 Aug 126,700 32,500 159,200 126,700 32,500 159,200 122,300 32,000 154,300 Sept. 120,000 23,800 143,800 120,000 23,800 143 800 115,800 23,500 139,300 Oct. 113,400 19,900 133,300 113,400 19,900 133,300 109,500 19,600 123,100 Nov. 110,300 27,500 137,800 110,300 27.500 137,800 100,500 27,100 133,000 Dec. Total or average 109,400 44,500 153,900 109,400 44,500 153,900 105,000 70,000 175,600 113,000 56,300 109,300 113,000 59,500 172,500 109,100 58,300 167,400 1917 Jan. 97,400 97,400 97,400 97,400 94,100 94,100 Feb. 101,900 101,900 101,900 11.600 113,500 98,500 11,900 110,400 Mar. 104,200 53,500 157,700 104,200 3,500 107,700 100,500 87,500 188,000 April 109,000 101,000 210,000 109,000 85,000 194,600 105,300 73,500 178,800 May 117,.500 89,000 206,500 117,500 89.000 206,500 113,300 96,700 210,000 June 124,200 40,300 164,500 124,200 40,300 164,500 119,700 90,300 210,000 July 125,400 22,700 148,100 125,400 22,700 148,100 121,100 37,500 158,000 Aug. 126,700 20,400 147,100 126,700 20,400 147,100 122,300 19,800 142,100 Sept. 120,000 11,900 131,900 120,000 11 900 151,900 115,800 11,700 127,500 Oct. 113,400 5,400 118,800 113,400 3,400 118,800 109,500 5,200 114,700 Nov. 110,300 20,000 130,300 110,300 20.000 130,300 106,500 19,700 126,200 Dec. Total or average 109,400 18,400 127,800 109,400 18,400 127,800 105,600 44,400 150,000 113,400 32,000 145,400 113,400 27,400 140,800 109,400 41,700 151,100 1918 Jan. 97,400 97,400 97,400 97,400 94.100 94,100 Feb. 101,900 101,900 101,900 101,900 98,500 98,500 Mar. 104,200 3.400 107,000 104,200 3.400 107,000 100.500 42,500 143,000 April May 109,000 91,100 200,100 109,000 91,100 200,100 105,300 21,400 129,700 117,500 12,000 129,.500 117,500 12,000 129,500 113,300 113,300 June 124,200 124,200 124.200 124,200 119,700 119,700 July 125,400 5,100 130,500 12.').400 5,100 130.500 121,100 121,100 Aug. 120,700 11,200 137,900 12'),700 11.200 137,900 122,300 1,200 12o,500 Sept. 120.000 12,400 132,400 120,000 12.400 132,400 115,800 12,200 128.000 Oct. 113,400 28,900 142.300 113,400 28.900 142,300 109,500 28.500 138,000 Nov. 110,300 29,000 13'J.300 110,300 29,000 139,300 106,500 28,800 135,300 Dec. Total or averego 109,400 3,600 113,000 109,400 3,600 113,000 105,600 28,800 134,400 113,400 16,300 129,700 113,400 16,300 129,700 109,400 14,000 123,400 1919 Jan. 07.400 97,400 97,400 29.000 126,400 94,100 94,100 Feb. 101,900 60,300 171,200 101.900 99.600 201,.500 98.500 83,800 182.300 Mar. 104.200 105,800 210,000 104.200 95.200 199,400 100.500 109,500 210,000 April May 109,000 101,000 210,000 109.000 97.600 206,000 105,300 40,400 151.700 117,500 04,100 181,000 117,500 64,100 181,000 113.300 00,500 173.800 Juno 124,200 7,100 131. .300 124,200 7,100 131.300 119,700 7,400 127.100 July 125,400 14,800 140,200 125,400 14,800 140,200 121.100 14,700 185,800 Aug. 120,700 14,200 140,900 120,700 14,200 140,900 122.300 14,400 136,700 Sept. 120.000 4.000 124,600 120,000 4,600 124,600 115,800 4.600 120,400 Oct. 113.400 0.500 119,iH)0 113,41)0 fi,.500 119.900 109,500 6.500 116,000 Nov. 110,300 4,200 114,500 110,300 4,200 114,500 106,500 4,200 •110,700 Dec. ToUl or average 109.400 109,400 109,400 109,400 105,600 105,600 113,400 32,400 145,800 113,400 36,000 149,400 109,400 29,000 138,400 •Total primary power production in February of leap years taken the same as in other years. THE CONTROL OP FLOODS BY RESERVOIRS. 293 RESERVOIR ON SACRAMENTO RIVER. BOTH WITH AND WITHOUT FLOOD CONTROL, la, 2a and 4a. mary, see Table 5, page 1 16.) Installed capacity of power plant 400,000 k.v.a. P.P. = 0.80. Operating primarily for irrigation with incidental power Generation SeasonaUrrigation yield 4,276,000 acre-feet. (Deficiency in supply one year in ten. no deduction for downstream prior rights). Average power yield in kilowatts (Load factor=1.00) Coordinated with flood control by reservoir operating diagram Year and Without flood control Maximam controlled flow month at Red Bluff 125,000 seo.-ft. Maximum reservoir space required 454,000 acre- feet Primary Secondary Total Primary Secondary Total 72,000 72,000 160,900 160,900 1916 277,900 277,900 278,500 278,500 Feb. 280,000 280,000 2.54,300 254,300 Mar. 269,200 269,''00 251,100 251.100 April May JUDG 280,000 280,000 280,000 280,000 280,000 280,000 280.000 280,000 280,000 280,000 280,000 280,000 July 266,900 266,900 266,900 266,900 Ajg. Sept. 151,800 151,800 151,800 151,800 47,000 47,000 47,000 47,000 Oct. Nov. Dec. 183,300 183,300 187,200 187,200 Total or average 1917 Jan. 17.900 17,900 17,900 17,900 Feb. Mar. 234,400 234,400 234.400 234,400 April May 280,000 280,000 280,000 280,000 280,000 280,000 280.000 280,000 June 280,000 280,000 280,000 280,000 July 263,400 263,400 263,400 263,400 Aug. 147,600 147,600 147,600 147,600 Sept. 44,600 44,600 44,600 44,600 Get. Nov. Dec. 129,700 129,700 129,700 129,700 Total or average n 1918 Jan. 16,900 16,900 16,900 16,900 Feb. Mar. 92,500 92,500 92,500 92.500 April 280,000 280,000 280,000 280,000 May 280,000 280.000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 197,400 197,400 197,400 197,400 Aug. oooc 1 Sept. Oct. Nov. Dec. 96,400 96,400 96,400 96,400 Total or average 1919 Jan. 143.100 143,100 209,800 209,800 Feb. Mar. 274,300 274,300 258,600 258,000 April 280,000 280,000 280,000 280,000 May 280.000 280,000 280,000 280,000 June 280,000 280,000 280,000 280,000 July 235,.500 235..500 235.500 235,500 Aug. 124,600 124,600 124,600 124,600 Sept. 35,600 35,600 35,600 35,600 Oct. Nov. Dec. 138,500 138,500 142,900 142,900 Total or average 294 WATER RESOURCES OP CALIFORNIA. Height of dam 420 feet. TABLE 5a (Continued). KENNETT SUMMARY OF POWER YIELD BY MONTHS Summary of Tables (For corresponding yearly sum Capacity of reservoir 2,940,000 acre-feet. Operating primarily for power generation with incidental irrigat on Average power yielc in kilowatt s (Load fact( )r=0.75) Coordinated with flood control With flood control, holding Year and by reservoir operating diagram maximum reservoir space month t\r:,l,„„, neld in kilowatts acre-feet (Load acre-feet (Load acre-feet (Load in acre-feet factor= 1.00) in acre-feet factor= 1.00) in acre-feet factor= 1.00) 1911 Jan. 19,030 2,430 19,030 5,090 19,030 7,470 Feb. 17,190 15.000 17.190 14,910 17,190 14,960 Mar. 19,030 15,000 19,030 15,000 19,030 15,000 April 18,410 15,000 18,410 15,000 18,410 11,740 May 19,030 15,000 19,030 15,000 19,030 14,090 June 18,410 15,000 18,410 15.000 18,410 15,000 July 19.030 13,130 19,030 13,130 19.030 12.620 Aug. 19,030 8.360 19,030 8,360 19,030 8.360 Sept. 18,410 3,580 18,410 3,580 18,410 3,580 Oct. 19,030 1,170 19,030 1,170 19,030 1,170 Nov. 18,410 18,410 18,410 1,000 Dec. Total or average 19,030 550 19,030 550 19,030 540 224,040 8,630 224,040 8,850 224,040 8,750 1912 Jan. 19,030 790 19,030 790 19,030 750 Feb. 17,800 2,260 17,800 2,260 17,800 2,140 Mar. 19,030 5,980 19.030 5.980 19,030 5,630 April 18.410 8,040 18,410 8,040 18,410 7,170 May 19,030 7,650 19,030 7,650 19,030 7,190 June 18,410 10,920 18.410 10,920 18.410 10.600 July 19,030 3,150 19,030 3,150 19,030 3,080 Aug. 19,030 1,720 19,030 1,720 19.030 1.680 Sept. 18,410 2,010 18,410 2,010 18,410 1,960 Oct. 19,030 860 19,030 860 19,030 830 Nov. 18,410 18.410 18,410 510 Dec. Total or average 19,030 3,090 19,030 3,090 19,030 2,920 224,650 3,870 224,650 3.870 224,650 3,700 1913 Jan. 19,030 690 19,030 690 19,030 650 Feb. 17.190 5,540 17.190 6,540 17,190 5,180 Mar. 19,030 8,760 19.030 8,760 19.030 8,010 April May 18,410 8,930 18.410 8,930 18,410 7,750 19,030 9,370 19,030 9.370 19,030 8,600 June 18,410 10,790 18,410 10,790 18,410 9,040 July 19.030 3,320 19,030 3,320 19,030 3,250 Aug. 19,030 2,550 19,030 2,550 19,030 2,490 Sept. 18.410 1,930 18.410 1,930 18,410 1,880 Oct. 19,030 850 19,030 850 19.030 820 Nov. 18,410 18,410 18,410 Deo. Total or average 19,030 19,030 19,030 224,040 4,370 224,040 4,370 224,040 3,950 THE CONTROL OF FLOODS BY RESERVOIRS, 327 TABLE 8a (Continued). PARDEE RESERVOIR ON MOKELUMNE RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 6a and 7a. (For corresponding yearly summary, see Table 8, page 128.) Height of dam 345 feet. Yield in municipal supply 200 million gallons daily. Capacity of reservoir 222,000 ac.-ft. Installed capacity of power plant 15,000 k.w. Without flood control Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements— rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Maximum reservoir space required— rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Flood control, holding maximum reservoir space (rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Year and Clements — rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. month Deficiency Average power Deficiency Average power Deficiency Average power Municipal draft in in municipal supply yield in kilowatts Municipal draft in in municipal supply yield in kilowatts Municipal draft in m municipal supply yiold in kilowatts acre-feet (Load acre-feet (Load acre-feet (Load in acre-feet factor= 1.00) in acre-feet factor= 1.00) in acre-feet factor= 1.00) 1914 Jan. 19,030 3,270 19,030 11,160 19,030 12,030 Feb. 17,190 15,000 17,190 12,920 17,190 13,660 Mar. 19,030 15,000 19,030 12,840 19,030 15,000 April 18,410 15,000 18,410 13,060 18,410 11,440 May 19,030 15,000 19,030 15,000 19,030 12,930 June 18,410 15,000 18,410 15,000 18,410 15,000 July 19,030 10,160 19,030 10,130 19,030 9,150 Aug. 19,030 6.330 19,030 6,330 19,030 3,760 Sept. 18,410 3,330 18,410 3,330 18,410 3,330 Oct. 19,030 2,000 19,030 2,000 19,030 2,000 Nov. 18,410 18,410 18,410 500 Dec. 19,030 19,030 19,030 Total or average 224,040 8,280 224,040 8,4.50 224,040 8,200 1915 Jan. 19,030 400 19,030 400 19,030 400 Feb. 17,190 4,270 17,190 6,860 17,190 10,890 Mar. 19,030 13,490 19,030 5,480 19,030 12,370 April 18,410 14,310 18,410 14,310 18,410 11,780 May 19,030 15,000 19,030 15,000 19,030 12.810 June 18,410 15,000 18,410 15,000 18,410 15,000 July 19,030 9,300 19,030 9,130 19,030 8,280 Aug. 19,030 3,050 19.030 3,050 19,030 1,770 Sept. 18,410 2,920 18,410 2,920 18,410 1,970 Oct. 19,030 1,160 19,030 1,160 19,030 860 Nov. 18,410 18,410 18,410 500 Dec. 19,030 19,030 19,030 Total or average 224,040 6,580 224,040 6,080 224,040 6,340 1916 Jan. 19,030 1,900 19,030 8,510 19,030 9,890 Feb. 17,800 14,740 17,800 14,470 17,800 14,740 Mar. 19,030 15,000 19,030 14,990 19,030 15,000 April 18,410 15,000 18,410 14,510 18,410 11,720 May 19,030 15.000 19,030 15,000 19,030 14,330 June 18,410 15,000 18,410 14,970 18,410 15,000 July 19,030 10,500 19,030 9,850 19,030 9,090 Aug. 19,030 6,100 19,030 6,100 19,030 3,980 Sept. 18,410 3,000 18,410 3,000 18,410 3,000 Oct. 19,030 1,730 19,030 1,730 19,030 1,730 Nov. 18,410 1,170 18,410 1,170 18,410 1,710 Dec. 19,030 280 19,030 280 19,030 1,510 Total or average 224,650 8,240 224,650 8.690 224,650 8,450 328 WATER RESOURCES OF CALIFORNIA. TABLE 8a (Continued). PARDEE RESERVOIR ON MOKELUMNE RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 6a and 7a. (For corresponding yearly summary, see Table 8, page 128.) Height of dam 345 feet. Yield in municipal supply 200 million gallons daily. Capacity of reservoir 222,000 ac.-ft. Installed capacity of power plant 15,000 k.w, Year and Without flood control Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements— rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Maximum reservoir space required — rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Flood control, holding maximum reservoir space (rain-water floods, 92,000 ac.-ft.: snow-water floods, 13,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Clements — rain-water floods. 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. month Deficiency Average power Deficiency Average power Deficiency Average power Municipal Jraf t in in municipal supply yield in kilowatts Municipal draft in in municipal supply yield in kilowatts Municipal draft in in municipal supply yield in kilowatts acre-feet (Load acre-feet (Load acre-feet (Load in acre-feet factor= 1.00) in acre-feet faotor= 1.00) in acre-feet factor= 1.00) 1917 Jan. 19,030 5,390 19,030 5,390 19,030 5.200 Feb. 17,190 4,640 17,190 5,360 17,190 5,890 Mar. 19,030 13,430 19,030 8,150 19,030 12,580 April 18,410 14,100 18,410 14,100 18,410 10,880 May 19,030 15,000 19,030 15,000 19,030 13,640 June 18,410 15,000 18,410 15,000 18,410 15,000 July 19,030 9,580 19,030 9,580 19,030 8,440 Aug. 19,030 5,130 19.030 5,130 19,030 2.960 Sept. 18,410 2,690 18.410 2,690 18.410 2,690 Oct. 19,030 1,160 19,030 1,160 19,030 1,160 Nov. 18,410 18,410 18,410 500 Dec. 19,030 19,030 19,030 Total or average 224,040 7,190 224,040 6,790 224,040 6,580 1918 Jan. 19,030 380 19,030 380 19,030 380 Feb. 17,190 2,620 17,190 2.620 17,190 2,080 Mar. 19,030 3,990 19,030 3,990 19,030 8,240 April 18,410 14,100 18,410 14,100 18,410 12,750 May 19,030 15,000 19,030 15,000 19,030 13,290 June 18,410 12,640 18,410 12,640 18,410 12,580 July 19,030 II 2,510 19,030 2,510 19,030 2,460 Aug. 19,030 (1 1,490 19,030 1,490 19,030 1,450 Sept. 18,410 2,690 18,410 2,690 18.410 2,610 Oct. 19,030 860 19,030 800 19,030 830 Nov. 18,410 18,410 18,410 70 Dec. Total or average 19,030 19,030 19,030 U 224,040 4,680 224.040 4.680 224,040 4,730 1919 Jnn. 19,030 1,630 19,030 1,630 19,030 1,570 Feb. 17,190 3,150 17,190 3,150 17.190 3,050 Mar. 19,030 12,590 19,0.30 12,590 19,030 12,180 April 18,410 13,400 18.410 13,400 18,410 12,250 May 19,030 15,000 19,030 15,000 19,030 14,490 Juno 18,410 8.130 18,410 8,130 18,410 8,080 July 19.030 1.7.50 19,030 1,750 19,030 1,710 Aug. 19.030 1,490 19,030 1,490 19,030 1.450 Sept. 18.410 1.560 18,410 1,560 18,410 1.510 Oct. 19.0.30 830 19,030 830 19,030 810 Nov. 18,410 18,410 18.410 Dec. Total or average 19,030 19.030 19.030 224,040 4.970 224.040 4,970 224.040 4.760 THE CONTROL OP FLOODS BY RESERVOIRS. 321) TABLE 8a (Continued). PARDEE RESERVOIR ON MOKELUMNE RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 6a and 7a. (For corresponding yearly summary, see Table 8, page 128.) Height of dam 345 feet. Yield in municipal supply 200 million gallons daily. Capacity of reservoir 222,000 ac.-ft. Installed capacity of power plant 15,000 k.w. Without flood control Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements — rain-water floods, 5,300 sec.-ft.; snow- water floods, 7,100 sec.-ft. Flood control, holding maximum reservoir space (rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Year and Maximum reservoir space required — rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Clements — rain-water floods, 5,300 sec.-ft.: snow-water floods, 7,100 sec.-ft. month Deficiency Average power Deficiency Average power Deficiency Average power 1 Municipal draft in municipal supply yield in kilowatts Municipal draft in municipal supply yield in kilowatts acre-feet ^^PP'^ yield in kilowatts 1 acre-feet (Load acre-feet (Load (Load 1 in acre-feet factor= 1.00) in acre-feet factor= 1.00) acre-feet factor^ 1.00) 1920 Jan. 19,030 380 19,030 1 380 19,030 360 Feb. 17,800 650 17,800 650 17,800 620 Mar. 19,03» 4,680 19,030 4,680 19,030 4,440 .\pril 18,410 9,110 18,410 9,110 18,410 8,250 May 19,030 10.990 19,030 10.990 19,030 10,980 June 18,410 12,830 18,410 12,830 18,410 12,760 July 19,030 4,400 19,030 4,400 19,030 4,300 .\ug. 19,030 1,800 19,030 1,800 19,030 1,760 Sept. 18,410 1,490 18,410 1,490 18,410 1,440 Oct. 19,030 860 19,030 860 19,030 830 Nov. 18,410 18,410 18,410 920 Dec. Total or average 19,030 19,030 19,030 4,090 224,650 3,930 224,650 3,930 224,650 4,230 1921 Jan. 19.030 7,630 19,030 13,200 19,030 10,650 Feb. 17,190 14,420 17,190 11,620 17,190 13,100 Mar. 19,030 14,910 19,030 10,970 19,030 15,000 April 18.410 15,000 18,410 10,400 18,410 12,280 May 19,030 15,000 19.030 15,000 19,030 13,270 June 18,410 15,000 18,410 14,850 18,410 15,000 July 19,030 5,690 19,030 5,420 19,030 5,560 .^ug. 19,030 2,410 19,030 2,410 19,030 2,350 Sept. 18,410 1,780 18.410 1,760 18,410 1,720 Oct. 19,030 870 19.030 860 19,030 850 Nov. 18,410 18,410 18,410 Dec. 19.030 19,030 19,030 Total or average 224.040 7,660 224,040 7,170 224,040 7,440 1922 Jan. 19,030 400 19,030 400 19,030 400 Feb. 17,190 940 17.190 2,650 17,190 4,790 Mar. 19,030 13,310 19,030 9.790 19,030 12.230 April 18,410 13,690 18,410 13,690 18,410 10.470 May 19,030 14,970 19,030 14,970 19,030 13.800 June 18,410 15,000 18,410 15,000 18,410 15,000 July 19,030 8,900 19,030 8,900 19.030 8,080 Aug. 19,030 4,720 19,030 4,720 19,030 3,120 Sept. 18,410 3,280 18.410 3,280 18,410 2,350 Oct. 19,030 1,140 19,030 1,140 19,030 950 Nov. 18.410 18.410 18,410 630 Dec. Total or average 19,030 19,030 19,030 5.160 224,040 6.390 224,040 [ 6,220 224,040 6,420 21—52 ni 330 WATER RESOURCES OF CALIFORNIA. TABLE 8a (Concluded). PARDEE RESERVOIR ON MOKELUMNE RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 6a and 7a. (For corresponding yearly summary, see Table 8, page 128.) Height of dam 345 feet. Yield in municipal supply 200 million gallons daily. Capacity of reservoir 222,000 ac.-ft. Installed capacity of power plant 15,000 k.w. Without flood control Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Clements — rain-water floods, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. Flood control, holding maximum reservoir space (rain-water floods, 92,000 ac.-ft.: snow-water floods, 13,000 ac.-ft.) in reserve throughout flood season Maximum controlled flow at Year and Maximum reservoir space required — rain-water floods, 92,000 ac.-ft.; snow-water floods, 13,000 ac.-ft. Clements — rain-water flood.s, 5,300 sec.-ft.; snow-water floods, 7,100 sec.-ft. month Deficiency Average power Deficiency Average power Deficiency Average power Municipal draft in in municipal supply yield in kilowatts Mimicipal draft in in municipal supply yield in kilowatts Municipal draft in in municipal supply yield in kilowatts acre-feet (Load acre-feet (Load acre-feet (Load in acre-feet factor= 1.00) in acre-feet factor= 1.00) in acre-feet factor= 1.00) 1923 Jan. 19,030 13,560 19,030 12,770 19.030 12,200 Feb. 17,190 13,050 17,190 5,980 17,190 11,500 Mar. 19,030 12.340 19,030 12,340 19,030 10,540 April 18,410 13,010 18,410 13,010 18,410 8.610 May- 19.030 14,790 19,030 14,790 19,030 12,740 June 18,410 15,000 18,410 14,830 18,410 15,CM)0 July 19,030 7.330 19.030 6.670 19.030 7.070 Aug. 19,030 2,850 19,030 2.840 19,030 2.780 Sept. 18,410 2.820 18,410 2,810 18,410 2,750 Oct. 19.030 870 19,030 870 19,030 850 Nov. 18,410 18,410 18,410 500 Dec. Total or average 19,030 19,030 19,030 224,040 7,930 224,040 7.250 224,040 7,010 1924 Jan. 19,030 2,310 19,030 2,300 19,030 2,200 Feb. 17,800 4,300 17,800 4,250 17.800 4.050 Mar. 19,030 2.650 19,030 2.620 19,030 2.460 .\pril 18.410 6,970 18,410 6.940 18,410 6.400 May 19,030 7,580 19,030 7,530 19.030 7,030 June 18,410 1,010 18,410 1,000 18.410 940 July 19.030 260 19.030 260 19,030 230 Aug. 19,030 70 19,030 50 9,150 9.880 30 Sept. 6,770 11,640 500 4.480 13,930 •490 18,410 490 Oct. 19,030 850 19,030 850 19,030 850 Nov. 18,410 2,990 18,410 2,990 18,410 2,970 Dec. Total or average 9.470 9.560 1,750 9,430 9,600 1,750 9,130 9,900 1,850 166.010 58,640 2.590 163,680 60,970 2,570 149,020 75,630 2.450 1925 Jan. 19.030 260 19.030 260 19,030 •260 Feb. 17,190 640 17.190 640 17,190 640 Mar. 19,030 3,780 19.030 3,780 19.030 11,2'.)0 April 18,410 14,530 18,410 14,530 18,410 12 141) May 19,030 15,000 19,030 15.000 19.030 13,970 June 18,410 15,000 18,410 14,540 18,410 14,920 July 19.030 5,390 19,030 5,230 19.030 5.240 Aug. 19,030 3.190 19,030 3,160 19,030 3.120 Sept. 18.410 2,470 18,410 2,440 18,410 2.400 Oct. 19,030 870 19,030 860 19,030 850 Nov. 18.410 18.410 18,410 Dec. Totel or average 19,030 19,030 19.030 224.040 5.100 224.040 5.040 224,040 5,420 Total for 21-year period. - - — - — — 1905-1926 4.649,250 58,640 4,646,920 60,970 4,632,260 75.630 Average for 21-year period, 1905-1926 221,390 2,790 6,640 221,280 2,900 6,510 220,580 3,600 6,450 THE CONTROL OF FLOODS BY RESERVOIRS. 331 ASSUMPTIONS EMPLOYED IN COMPUTING WATER AND POWER YIELD OF TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER ON A DAILY BASIS. 1. The water siip])ly at the dam site is the same as that measured at the Friant araofinp^ station of the TTnited States Geological Survey and published or in preparation for publication, as mean dail.y discharges in the Water Supply Papers. No deductions were made for down- stream prior rights. 2. The reservoir is full on June 1, 1907, the opening date of the estimates. The run-off index for the season 1906-1907 is 156. The reservoir fills in 1917 with a run-off index of 94. 3. The net evaporation from the reservoir surface equals 4.0 feet depth per annum, divided among the months as follows : Per cent Depth in of seasonal Month feet total April 0.37 9.2 May 0.;50 12.6 .Tune 0.60 15.0 July 0.71 17.8 August 0.66 16.6 September 0.51 12.7 October 0.39 9.6 Xovember 0.26 6.5 Totals 4.00 100.0 4. The total .seasonal draft from the reservoir for irrigation is divided among the months as f o11o"\\t^ : (The summer peak of the irri- gation demand is carried by pumping from wells.) Demand in per cent of total Month seasonal use .January — 0.0 February 2.6 March 6.6 April 14.5 May 14.5 .Tune 14.5 July 14.5 August 14.5 September 13.1 October 5.2 November 0.0 December 0.0 Total 100.0 5. The seasonal irrigation yield is that which can be obtained from the reservoir during the period 1872-1925 with a deticiency, when supple- mented by pumping from ground water, not oftener on the average than one year in 18. 6. Power is generated in a plant at the ba-se of the dam with water drawn from the reservoir for irrigation and with reservoir spill. The load factor is 1.00 and the power factor 0.80. 7. Secondary power is intermittent power. IB 8. The overall plant efficiency increa.se.s from 75.0 per cent at full reservoir to 78.7 per cent at 0.8 depth and then decreases to 73.5 per cent at 0.5 depth. 9. The elevation of the tail race rises 18 feet when 20,000 second- feet are passing the dam, 13 feet when 30,000 second-feet are passing, 8 feet when 5000 second-feet are passing, and corresponding amounts i for other flows. -.V.i'l WATER RESOURCES OF CALIFORNIA. TABLE 9a TEMPERANCE FLAT RESER WATER AND POWER YIELD BOTH WITH AND WITHOUT Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-off at Friant Without flood control Irrigation Average Year and month Stage of reservoir draft in acre-feet Power Waste Deficiency power head .Average power in acre-feet at (no Evapora- draft over in irrigation supply through yield in beginning deduction tion in through spillway period lulowatts of for down- acre-feet turbines in of (Load month in acre-feet stream prior rights) in acre-feet acre-feet in acre-feet operation in feet factor= 1.00) 1908 Jan. 53,100 797,100 Feb. .18.100 850,200 47,000 47.000 548 29 200 Mar. 120,000 861,300 119,000 119.000 543 68,400 .\pril 199,000 862,300 261.000 1,700 261.000 530 152,400 1 May 219,000 798,600 261,000 2,200 261,000 522 145,800 June 176,000 754,400 261.000 2,600 261,000 507 146,900 July 119,000 666,800 261,000 2.800 261.000 478 135,100 Aug. "3,200 522,000 261.000 2,300 261,000 429 121,100 Sept. 39.000 331,900 236,000 1,300 228,100 347 86,800 Oct. 23,900 133,600 93,000 000 Nov. 16,200 63,900 200 Dec. Total or average 18,500 79,900 1,11.5,000 1,800,000 13,700 1.699,100 488 73,800 1909 Jan. 277,000 98,400 Feb. 183,000 375,400 47,000 47.000 4.38 24,700 Mar. 133,000 511,400 119,000 119,000 460 59.300 .\pril 3.52,000 525,400 261.000 1,300 261,000 459 1.34,200 May 646,000 615,100 261,000 1,900 261,000 531 147.700 June 827,000 998,200 261,000 3,100 265,400 485,700 574 164.200 July 309,000 1,071,000 261.000 3,800 268,000 82,900 578 161,000 Aug. 78,100 1,025,300 261,000 3,500 261,000 554 152,400 Sept. 37,000 838,900 236,000 2,400 236,000 512 134.200 Oct 25.000 637,500 93,000 1,500 93,000 482 48,500 Nov. 49,600 568.000 900 Dec. Total or average 220,000 616.700 3,136.700 1.800,000 18.400 1,811.400 568,600 510 85.800 1910 .)uii. 188,000 836,700 Feb. 86,600 1,024,700 47,000 47.000 586 31. .500 Mar. 188,000 1,064,300 119,000 181,300 & 584 10!>.7O0 April 375,000 1.071.000 261,000 2,000 262,400 110,600 580 I6:i,.i00 May 475,000 1,071,000 261,000 2,700 273,300 199.000 579 164,400 June 237.000 1,071,000 261,000 3,200 261,600 37,700 578 162,600 July 99,600 1,005,500 261,000 3,700 261.000 554 152,300 Aug. 39,600 840,400 261,000 3.100 261,000 509 142,900 Sept. 51,700 615,900 2.36,000 1.900 236.000 456 120,400 Oct. 29,600 429,700 93,000 1,200 93.000 419 42,200 Nov. 24,000 365,100 700 Dec. 31.400 388.400 Total or avor;iKe 1,825.500 1,800,000 18,500 1.876,600 347,300 538 91.100 1911 Jan. 239,000 419.800 Feb. 207,000 658,800 47,000 47,000 526 29,200 Mur 336,000 818,800 119,000 119,000 558 69,900 April 425,000 1,035.800 261,000 1,900 264,000 123,900 578 164.300 May 571,000 1.071,000 261,000 2,700 273,400 294,900 578 164.400 Juiii- 940,000 1.071,000 201.000 3,200 265,600 677,200 575 164.400 July 593,000 1.071,000 261.000 3,800 272,700 320,500 576 163.400 Aug. 116.000 1.067,000 261.000 3,500 261,000 569 155.200 Sept. 45.500 918,500 236.000 2.400 236,000 532 138,200 Oct. 32,300 725,600 93,000 1.600 93,000 507 50,700 Nov. 28.000 663,.30O 1,000 Dec. Total or average 23.400 690.300 3,.S62.200 1,800,000 20,100 1,831,700 1,416,500 556 91,900 THE CONTROL OF I-^LOODS BY RESERVOIRS. 333 VOIR ON SAN JOAQUIN RIVER. FLOOD CONTROL BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9, page 134.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.P. =0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Friant — rain-water floods, IC ,700 sec.-ft snow-water floods, 14,200 sec.-ft. Maximum reservoir space reauired— rain-water floods, 133,000 ac.-ft.; snow-water floods. 177,000 ac.-ft. Irrigation Average Stage of reservoir draft in acre-feet Power Release through flood control oatlets in iicre-feet Waste Deficiency power head Average power Year and month at (no Evapor?- draft over in irrigation supply through yield in beginning dedaction tion in through spillway period kilowatts of for down- acre-feet turbines in of (Load month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in factor= 1.00) rights) feet 1908 797,100 Jan. 850,200 47,000 47,000 548 29,200 Feb. 861.300 119,000 119,000 543 68,400 Mar. 862,300 261,000 1,700 261,000 530 152,400 April 798,600 261,000 2.200 261,000 522 145,800 Mav 75-1.400 261.000 2.600 261,000 507 146,900 .June 666.800 261.000 2,800 261,000 478 135,100 July 522,000 261.000 2.300 261,000 429 121,100 .^ug. 331,900 236.000 1.300 228,100 347 86,800 Sept. 133,600 93.000 600 Oct. 63,900 200 Nov. 79,900 Dec. Total or average 1,800,000 13,700 1,699,100 488 73,800 1903 98.400 Jan. 375,400 47,000 47,000 438 24,700 Feb. 511,400 119,000 119,000 460 59,300 Mar. 525,400 261.000 1.300 261,000 459 134,200 April 61.S,100 261.000 1.900 266,400 86,700 529 150,300 May 906,100 261.000 2.900 273,000 484,800 553 164,400 June 972,400 261,000 3.600 263,900 34,400 568 156.000 July 979..500 261,000 3,400 261,000 543 1.50.300 Aug. 793,200 236,000 2,300 236.000 500 131,400 Sept. 591,900 93,000 1,500 93,000 468 47,200 Oct. 522,400 900 Nov. 571,100 Dec. Tntal or average 1,800,000 17,800 1,820,300 605,900 503 85,100 1910 791,100 Jan. 979,100 47,000 87,600 900 567 57,600 Feb. 977,200 119.000 123,200 574 73,800 Mar. 1,042,000 261.000 1.900 262,200 33,800 66,.500 576 162,600 .\pril 1,052,600 261,000 2.700 280,900 328,800 556 164,400 May 91.5,200 261.000 2.900 263,300 37,800 547 157,400 June 848,200 261.000 3.300 261,000 520 145,200 July 683,500 261.000 2,700 261.000 469 132,700 Aug. 4.59.400 236.000 1.600 236,000 398 104,900 S;pt. 273.500 93,000 900 93,000 357 35,500 Oct. 209,200 500 Nov. 232.700 Dec. Total Df average 1,800,000 16,500 1,868,200 401,300 66,500 506 86,200 1911 264.100 Jan. .503.100 47,000 47,000 489 27,500 Feb. 663,100 119,000 119,000 1 525 66,700 Mar. 880,100 261,000 1,800 261,000 1 561 158,900 Anril 1,042.300 261.000 2,600 280,000 430,500 557 164,000 May 900,200 261,000 2,900 272,300 541,900 555 164,400 Ju"e 1,029,100 261,000 3,700 273,100 203,700 74,600 574 163,300 July 1,067,000 261,000 3,.500 261,000 569 155.200 Aug. 918,500 236.000 2.400 : 236,000 ; 1 532 138,200 S-pt. 725,600 93,000 1.600 93,000 507 50,700 1 Oct. 663,300 1,000 Nov. 690,300 Dec. To h1 or aver ige 1,800,000 19,500 1,842,400 1,176,100 74,600 542 91,000 334 WATER RESOURCES OF CALIFORNIA. TABLE 9a (Continued). TEMPERANCE FLAT WATER AND POWER YIELD BOTH WITH AND WITHOUT Monthly Summary of Computations (For correspx)nding yearly sum Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-off at Friant in acre-feet Without flood cofilrol Year and month SUgeof reservoir at beginning of month in acre-feet Irrigation draft in acre-feet (no deduction for down- stream prior rights) Evapora- tion in acre-feet Power draft through tiirbines in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet •Average power head through period of operation in feet Average power yield in kilowatts (Load factor=: 1.00) 1912 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or 30,100 26,600 55,200 75,000 255,000 368,000 95,300 38,000 22,400 17,800 20,300 20,000 713,700 743,800 723,400 659,600 472,100 464,500 569,600 401,300 176,400 20,300 47,000 119,000 261,000 261,000 261,000 261,000 261,000 198,100 17,800 1,500 1,600 1,900 2,600 1,900 700 47,000 119,000 261,000 261,000 261,000 261.000 261,000 39.300 37,900 75,200 52i 505 468 431 472 445 367 305 28.000 64,700 136,700 121,8001 137,900» 125,800^ 102,70W 12,80O«, 1 avpragp 1913 Jan. Feb. Mar. April May June July Aug. Sppt. Oct. Nov. Dec. Total or 1,023,700 22,100 25,700 38,200 95,800 247,000 170,000 102,000 68,900 40,600 12,800 22.300 28,700 40,300 62,400 41,100 27.800 22,300 1,686,900 47,000 79,300 95,800 219,200 197.700 102,000 68,900 40,600 12,800 10,200 100 1,510,300 113,100 39,700 165,200 41,800 63,300 159,000 192,100 195,400 80.200 454 60,900 average 1914 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or 874,100 259,000 145,000 234,000 395.000 577,000 607,000 392,000 142,000 53,900 40,300 30,.5O0 29,600 51,000 310,000 408.000 523.000 655,700 969,700 1,071,000 1,007,200 944,700 760.100 705.700 735.100 863.300 47,000 119,000 261,000 261,000 261,000 261,000 261,000 236,000 93.000 100 1,300 2,000 3,000 3,800 3,500 2,500 1,700 1,100 47,000 119,000 261,000 261,000 263,700 269,900 261,000 236,000 93,000 239.000 122,100 936,700 404 439 475 520 578 579 573 537 514 22,800 56,60Ot Hsison 163,80i 162,508 156.1001 139.30g avpragp 1915 .Ian. FpI.. Mar. April May June July Aug. Sept. Oct. Nov. Dee. Total or 2,905.300 38,200 90,000 124,000 246.000 381.000 686.000 287.000 70.100 44,300 26.700 23.400 37,900 764.700 802.900 845,900 850,900 834,200 951,900 1.071.000 1,037,400 813,000 648.900 581,100 603,500 1.800,000 47,000 119,000 261,000 261,000 261,009 261,000 261.000 236,000 93.000 18,900 1,700 2,300 3.000 3.800 3,500 2,400 1.500 1,000 1,811,600 47,000 119,000 261,000 261,000 263,400 266.900 261.000 236.000 93.000 361,100 200,500 49,900 U 514 5.38 539 533 541 577 579 557 514 485 esiiol 153,10^ 149,90*. 163.300' 160,800' ISS.OML 134.60y 48,800^ average 1.954.600 1,800,000 19.200 1.808.300 250,400 540 88.70«t ■ ^ THE CONTROL OF FLOODS BY RESERVOIRS. 335 RESERVOIR ON SAN JOAQUIN RIVER. FLOOD CONTROL BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9, page 134.) supply in years of deficiency. No deduction for downstream prior rights, ) Installed capacity of power plant 220,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Frbnt — rain-water floods, 10,700 sec.-ft.; snow-water floods, 14,200 sec.-ft Maximum reservoir space required — rain-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac. ft. Irrigation Average Stage of draft in Relepse through flood cojitrol outlets in acre-feet Deficiency pOWrt Average Year and reservoir acre-feet Power Waste head power month at (no Evapora- draft over in irrigation supply through yield in lieginnmg deduction tion in through spillway period kilowatts of for down- acre-feet tiirbines in of (Load month in acre-feet stream prior in acre-feet acre-feet in acre-feet operation in factor= 1.00) rights) feet 1912 713,700 .Jan. 743,800 47,000 47,000 52 i 28,000 Feb. 723,400 119,000 119,000 505 64.700 Mar. 653,600 261,000 1,500 261,000 468 136,700 April 472,100 261,000 1,600 261,000 431 121,800 May 461,500 261,000 1,900 261,000 472 137,900 .Tunc 569,600 261,000 2,600 261,000 445 125.800 July 401.300 261,000 1,900 261,000 367 102.700 Aug. 176,400 198,100 700 39,300 37,900 305 12,800 Sept. 17,800 75,200 Oct. Nov. 20,300 Dec. Total or average 1,686,900 10,200 1,510,300 113,100 454 60,900 1913 40,300 Jan. 62,400 47,000 Feb. 41,100 79,300 39,700 Mar. 95,800 165,200 ■ • 1 April 219,200 41,800 May 27,800 197,700 100 63,300 - June 102,000 159,000 July 68,900 192,100 Aug. 40,600 195,400 Sept. 12,800 80,200 Oct. Nov. 22,300 Dec. Total or average 863,300 100 936,700 1914 51,000 Jan. 310,000 47,000 47,000 404 22,800 Feb. 408,000 119,000 119,000 439 56,600 Mar. 523,000 261,000 1,300 261,000 475 138,800 April 655,700 261,000 2,000 264,300 66,800 519 146,800 May 899,600 261,000 2,900 275,100 264,900 547 164,400 June 963,700 261,000 3,600 265,000 26,200 574 158,600 July 1,000,900 261.000 3.500 261,000 573 156,100 Aug. 938,400 236,000 2,500 236,000 537 139,000 Sept. 753,800 93,000 1,700 93,000 513 51,200 Oct. 699,400 1,100 Nov. 728.800 Dec. Total or average 1,800,000 18,600 1,821,400 357,900 510 86,400 1915 758,400 Juii. 7%,600 47,000 47,000 537 29,600 Feb. 839,600 119,000 119,000 537 67,900 Mar. 844,600 261,000 1,700 261,000 532 152,800 Anril 827,900 261,000 2,300 264,100 44,300 538 151,100 May 898,200 261,000 2,900 275,200 241,300 547 164,400 June 964,800 261,000 3,600 263,300 2,}00 508 156,500 Jdy 982,800 261,000 3,400 261,000 .545 150,700 Aug. 788,500 236,000 2,300 236,000 1) 500 131,400 Sept. 594,500 93,000 1,500 93,000 466 47,000 Oct. 523,700 900 Nov. 549,200 Dec. Total >:t average 1,800,000 18,600 1,819,600 287.700 530 87,800 336 WATER RESOURCES OP CALIFORNIA. TABLE 9a (Continued). TEMPERANCE FLAT WATER AND POWER YIELD BOTH WITH AND WITHOUT Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield, 1,800,000 acre-feet. 'Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-off Without flood control Irrigation Average Year and at Stage of draft in Deficiency power -Average month Friant reservoir acre-feet Power Waste in head power in at fno Evapora- draft o\er irrigation through yield in acre-feet beginning deduction tion in through spillway supply period kilowatts of for down- acrc-fect turbines in in of (I-oad month in stream in acre-feet arre-feet acre-feet operation factor= acre-feet prior in 1.00) rights) feet 1916 Jan. 173,000 641,400 Feb. 142,000 814,400 47,000 47,000 545 29.000 Mar. 338,000 909,400 119,000 162,100 14,300 .571 97,000 .\pril 477,000 1,071.000 261,000 2,000 264,000 211.000 580 164,400 .May 5-52,000 1.071,000 261,000 2,700 273.300 276,000 578 164,400 .June 572,000 1,071,000 201,000 3.200 264,800 304,000 578 164.400 .luly 289,000 1.071,000 261.000 3,800 267,600 44,300 580 161,300 .\ug. 91,000 1,044,300 261,000 3,.500 261,000 561 153,800 Sept. 44,900 870,800 236,000 2,400 236,000 520 135,800 Oct. 63,900 677,300 93.000 1,600 93,000 499 50,100 Nov. 38,900 646,600 1,000 Dec. 45,300 684,500 Total or average 2.827,000 1,800,000 20,200 1,868,800 840,600 557 93,500 1917 Jan. 47,500 729,800 Feb. 129.000 777,300 47,000 47,000 53i 29.500 Mar. 108,000 859.300 119,000 119,000 542 68,400 .April 226,000 848.300 261,000 1,700 261,000 530 152,500 May 373,000 811. 6C0 261,000 2.,300 261.000 .540 149,600 June 579,000 921,.300 261.000 3.000 262.500 163.800 575 162,600 July 222,000 1,071,000 261.000 3.800 264,200 13,100 579 159,100 Aug. 72,600 1,011,900 261,000 3.400 261.000 5.53 152,200 Sept. 36,100 820,100 236,000 2,300 236.000 507 133,200 Oct. 25,400 617,900 93,000 1,500 93,000 477 48,000 Nov. 21,900 548,800 900 Dec. 19,600 569,800 Total or average 1.860,100 1,800,000 18,900 1,804,700 176,900 537 88.100 1918 Jan. 20,500 .589,400 Feb. 36,800 609,900 47,000 47.000 484 27,200 Mar. 149,000 599,700 119,000 119,000 483 62,200 .\pril 179,000 629,700 261,000 1,400 261,000 477 139,300 May 307.000 646,300 261,000 1,800 261,000 470 132,900 June 494.000 590.500 261,000 2.200 261,000 510 147,800 July 121,000 821,300 261,000 3,400 261,000 517 144,600 •Aug. 42,800 677.900 261,000 2,700 261,000 467 132,100 Sept. 48,700 457,000 236,000 1,600 236,000 403 106.100 Oct. 103,000 268,100 93,000 900 93,000 382 38,,300 Nov. 44.000 277,200 600 Dec. Total or .Tvoriigo 50,700 320,600 1.596,500 1,800,000 14,600 1,800,000 466 77,700 1919 Jan. 38,400 371,300 Feb. 68.900 409.700 47,000 47,000 4.30 24..300 Mar. 94.100 431,600 119,000 119,000 427 .55,000 .\pril 209,000 406,700 261.000 1,100 261,000 407 118,600 May 441,000 353,600 261,000 1,300 261,000 430 121,500 June l.'>4,000 532,300 261,000 2.100 261,000 447 130,600 July 61,500 423,200 261,000 2,100 261.000 389 109,500 Aug. 30,400 221,600 250,300 1,700 92,600 10,700 320 30,800 Sept. 23,000 23,000 213,000 Oct. 22,400 22,400 70,600 Nov. 18,600 (1 Dec. Total or average 30.100 18,600 1,191.400 1,505.700 8,300 1,302.600 294,300 416 49,200 THE CONTROL OF FLOODS BY RESERVOIRS. 'S'M RESERVOIR ON SAN JOAQUIN RIVER. FLOOD CONTROL BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9, page 134.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir ooeratlnq diaaram Maximum controlled flow at Friant— rain-water floods, 10 ,700nec.-ft.; snow-water floods, 14,200 sec.-ft. Maximum reserv:,ir space required— rain-wat er floods, 133,000 ac.-ft.: mow-water flood.s, 177,000 ac.-ft. Stage of Irrigation Average reservoir at beginning of month in acre-feet draft in acre-feet (no deduction for down- stream prior rights) Eyapora- tion in acre-feet Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre- feet power head through period of operation in feet Average power yield in kilowatts (Load factor = 1.00) Year and month 1916 587.100 .Ian. 760,100 47,000 47.000 532 28,400 Feb. 855,100 119,000 122,100 562 72,000 Mar. 1.071,000 261,000 2,000 264.300 210,700 579 164,400 A Til 1,071,000 261.000 2,700 280.100 417,600 21,.500 558 161,400 May 901,100 261,000 2,900 274.000 226,000 549 104,300 .lunp 909,600 201,000 3,600 261.000 569 155,400 Julv 994,000 261,000 3.400 261,000 551 151,700 Aug. 820,600 2.36,000 2,300 236,000 509 133,300 Sept. 627,200 93,000 1,.500 93,000 486 48,900 Oct. 596,600 1,000 Nov. 634,500 Dec. Total or average 1,800,000 19,400 1,838,500 644,200 232,200 544 90,300 1917 679,800 Jan. 727,300 47,000 47,000 519 28,900 Feb. 809,300 119,000 119,000 531 07,300 Mar. 798,300 261,000 1,700 261,000 518 149,700 April 761,600 261,000 2.200 261,000 530 147,400 May 871,400 261,000 2,800 262,900 57,600 56,100 569 161,400 June 1,071,000 261,000 3.800 264,200 13,100 579 159,100 July 1,011,900 261,000 3.400 261,000 553 152,200 Aug. 820,100 236,000 2,300 230,000 507 133,200 Sept. 617,900 93,000 1,500 93,000 477 48,000 Oct. 548,800 900 Nov. 569,800 Dec. Total or average 1,800,000 18,600 1,805,100 57,600 69,200 532 87,500 1918 589,400 Jan. 609,900 47,000 47,000 484 27,200 Feb. 599,700 119,000 119,000 483 62,200 Mar. 629,700 261,000 1,400 261,000 477 139,300 .\pril 546.300 261,000 1,800 261,000 470 132,900 Mav 590,500 261,000 2,200 261,000 510 147,800 June 821,300 261,000 3,400 261,000 517 144,600 Julv 677,900 261,000 2,700 261,000 467 132.100 A UK. 457,000 235,000 1,000 236,000 403 106.100 S"p(. 268,100 93,000 900 93,000 382 38.300 Oct. 277,200 600 Nov. 320.600 Dec. 1,800,000 14,600 1,800,000 466 77,700 Total or avonigr 1919 371,.300 Jan. 409,700 47,000 47,000 430 24,300 Feb. 431,600 119,000 119,000 427 55,000 Mar. 406,700 261,000 1,100 261,000 407 118,600 April 353,600 261,000 1,300 261,000 430 121,500 May 532,300 261,000 2,100 261,000 447 130,600 June 423,200 261.000 2,100 261,000 389 109,.500 July 221,600 250,300 1,700 92,600 10,700 320 30,800 Aug. 23.000 213,000 S.'pt. 22,400 70,000 Oct. (1 Nov 18,600 Dec. Total or average 1,. 505,700 8,.30O l,.3O2,6O0 294,300 416 49,200 338 WATER RESOURCES OF CALIFORNIA. TABLE 9a (Continued). TEMPERANCE FLAT WATER AND POWER YIELD BOTH WITH AND WITHOUT Monthly Summary of Computations ("For corresponding yearly sum Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-off Withoiit flood control Irrigation Average Year and at Stage of draft in Deficiency power Average month Friant reservoir aore-feet Power Waste in head power in at_ Tno Evapora- draft over irrigation through yield in acre-feet beginning deduction tion in through spillway supply period kilowatts of for down- acre-feet turbines in in of fLoad month in stream in acre-feet acre-feet acre-feet operation factor= acre-feet prior rights) in feet 1.00) 1920 Jan. 26,900 48,700 Feb. 28.900 75,600 47,000 Mar. 101,000 57,500 119,000 April 161,000 39,500 198,000 63.000 May 407.000 2.500 259,600 8,400 1,400 298 2,600 .lune 327.000 149,900 261,000 900 261,000 336 95,700 .July 111,000 215,000 261,000 1,400 151,500 320 50,-500 .^ug. 4.5,400 63,600 108,900 100 152,100 Sept. 29.200 29,200 206,800 Oct. 37,000 37,000 56,000 Nov. 44,600 Dec. Total or average 43,000 44,600 1,362,000 1,320,700 2,400 420.900 479,300 329 12,300 1921 .Ian. 67,600 87,600 Feb. 77,800 155,200 47,000 47,000 3i7 17,100 Mar. 162,000 186,000 119,000 119,000 340 42,900 April 189,000 229,000 261,000 700 261,000 322 90,700 May 323.000 156,300 261,000 800 201,000 324 88,400 June 407,000 217,500 261,000 1,200 261,000 379 110,100 July 1.55,000 362,300 261,000 1,400 261,000 390 109.900 Aug. .51,600 254,900 261,000 1,400 151.500 327 52,000 Sept. 34,700 44,100 78,700 100 157,300 Oct. 26,.30O 26,300 66,700 Nov. 23.000 Dec. Total or average 63,300 23,000 1,580,300 1,576,000 5,600 1,361,500 224,000 344 42.700 1922 ■Jan. 67,600 86,300 Feb. 96,100 153,900 47,000 47,000 32 i 17,400 Mar. 103,000 203,000 119,000 119,000 328 41,000 April 193,000 187,000 261,000 700 130,500 308 42,800 May 021,000 118.300 261,000 700 244,200 367 96.200 June 732,000 477.600 261,000 1,900 261,000 512 148,300 July 270,000 946,700 261,000 3,600 261,000 565 154.600 Aug. 84,800 9,52,100 261,000 3,600 261,000 542 150.000 Sept. 43,400 772,300 236,000 2,200 236,000 498 131. 00() Oct. 31,900 577,500 93.000 1,400 93,000 466 46,900 Nov. 42,400 515.000 900 Dec. Total or average 91,600 556,500 2,376,800 1,800,000 15,000 1,652,700 443 69,300 1923 Jan. 69,500 648,100 Feb. 70,000 717,600 47,000 47,000 520 29,000 Mar. 95,900 740,600 119,000 119,000 513 65,600 April 199,000 717,500 261,000 1,600 261,000 500 145,400 May 450,000 6.53,900 261.000 2,000 261,000 513 143,800 June 287.000 840,900 261,000 2.800 261,000 538 154,200 July 201,000 864,100 261,000 3,300 261,000 539 149,500 Aug. 72,600 800,800 261,000 2.900 261,000 .507 142,300 Sept. .50,900 609.500 2.30.000 1.900 236.000 453 119.900 t)ct. 48,300 422,500 93,000 1,200 93,000 II 420 42.200 Nov. 33.000 376.600 700 Dec. 27,700 408,900 Total or average 1,604,900 1.800,000 16,100 1,800,000 500 82,900 THE CONTROL OP FLOODS BY RESERVOIKS. 339 RESERVOIR ON SAN JOAQUIN RIVER. FLOOD CONTROL BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9, page 134.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.P. =0.80. [Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Friant — rain-water floods, 10 700sec.-ft.; snow-water floods, 14,20C sec.-ft. Maximum rejervoir space required— rain-water floods, 133,000 ac.-ft. ; snow-water floods, 177,00C ac.-ft. Stage of reservoir Irrigation Average draft in acre-feet Power Release through flood control outlets in acre-feet Waste Deficiency power head Average power Year and month at beginning (no deddction Evapora- tion in draft through over spillway in irrigation supply in acre-feet through period yield in kilowatts 01 month in acre-feet for down- stream prior acre-feet turbines in acre-feet in acre-feet of operation in (Load factor = 1.00) rights) feet 1920 48,700 Jan. 75,600 47,000 Fel). 57,500 119,000 Mar. 39,500 198,000 03,000 April 2,500 259,600 8,400 1,400 298 2,600 May 149,900 261,000 900 261,000 336 95,700 June 215,000 261,000 1,400 151,.500 320 50,500 July 63,600 108,900 100 152,100 ' Aug. 29,200 206,800 Sept. 37,000 56,000 Oct. Nov. 44,600 Dec. Total or average 1,320,700 2,400 420,900 479,300 329 12,300 1921 87,600 Jan. 155,200 47,000 ■ 47,000 3i7 17,100 Feb. 186,000 119,000 119,000 340 42,900 Mar 229,000 261,000 700 201,000 322 90,700 April 156,300 261,000 800 261,000 324 88,400 May 217,500 261,000 1,200 261,000 379 110,100 June 362,300 261,000 1,400 261,000 390 109,900 July 254,900 261,000 1,400 151,500 327 52,000 Aug. 44,100 78,700 100 157,300 Sept 20,300 66,700 Oct. Nov. 23,000 Dec. Total nr average 1,576,000 5,600 1,361,500 224,000 344 42,700 1922 86,300 Jan. 153,900 47,000 47,000 32 i 17.400 Feb. 203,000 119,000 119,000 328 41,000 Mar 187,000 261,000 700 130,500 308 42,800 .\pril 118,300 261,000 700 244,200 367 96,200 May 477,600 261,000 1,900 261,000 512 148,300 June 946,700 261,000 3,600 261,000 565 151,600 July 952,100 261,000 3,600 261,000 542 150,000 Aug. 772,300 236,000 2,200 236,000 498 131,000 Sept. 577,500 93,000 1,400 93,000 466 46,900 Oct. 515,000 900 Nov. ,556,500 Dw. Total or average 1,800,000 15,000 1,652,700 443 69,300 1923 648,100 Jan. 717,600 47,000 47,000 520 29,000 Feb. 740,600 119,000 119,000 513 65,600 Mar. 717,500 261,000 1,600 261,000 500 145,400 April 653,900 261,000 2,000 261,000 513 143,800 May 840,900 261,000 2,800 251,000 538 154,200 June 864,100 261,000 3,300 261,000 539 149,,500 July 800,800 261,000 2,900 261,000 507 142,300 Aug. 609,500 236,000 1,900 230,000 453 119,900 Sept. 422,500 03,000 1,200 03,000 420 42,200 Oct. 376,600 700 Nov. 408,900 Dec. Total or average 1,800,000 16,400 1,800,000 500 82,900 340 WATER RESOURCES OF CALIFORNIA. TABLE 9a (Concluded). TEMPERANCE FLAT WATER AND POWER YIELD BOTH WITH AND WITHOUT Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Run-oR at Friant Witho It flood control Irrigation Average Year and month Stage of reservoir draft in acre-feet Power Waste DeBciency power head Average power in acre-feet at beginning (no deduction Evapora- tion in draft through over spillway in irrigation supply through period yield in kilowatts of for down- acre-feet turbines in of (Load month in stream in acre-feet acre-feet in acre-feet operation factor= acre-feet prior in 1.00) rights) feet 1924 Jan. 26,900 436,600 Feb. 22,600 463,500 47,000 47,000 445 24.100 Mar. 25,800 439,100 119,000 119,000 419 54.000 .\pril 8.3,300 345,900 261,000 1,000 261,000 356 102.600 .May 152,000 167,200 261,000 800 109,400 304 34,100 .lune 37,800 57,400 95,100 100 165,900 July 20,600 20,600 240,400 Aug. 16,200 16,200 244,800 S3pt. 12,700 12,700 223.300 Oct. 17,700 11,700 81,300 n Nov. 27,800 Dec. Total or average 28,700 27,800 466,100 844,300 1,900 536,400 955,700 394 17,800 1925 Jan. 27,100 56,500 Feb. 77,800 83,600 47,000 Mar. 94,700 114,400 119,000 .\pril 196,000 90,100 261,000 400 May 364,000 24,700 261,000 200 June 281,000 127,500 261,000 800 60,900 298 19.000 July 151,000 146,700 261,000 1.100 50,500 298 15,300 Aug. 65,800 35,600 101,300 100 159,700 Sept. 37.100 37,100 198,900 Oct. 39,200 39,200 53,800 Nov. 3?,900 Dec. Total or average 40,800 38,900 1,413,400 1,387,600 2,600 111,400 412,400 298 2,900 Total for 18-year period, 1908-1926 32,675,600 2a984,500 225,000 25,008,000 3,970,400 3,415,500 Average for 18-year period, 1908-1926 1,815.300 1,610,300 12.500 1,389,300 220,600 189,700 490 62.000 THE CONTROL OF FLOODS BY RESERVOIRS. 341 RESERVOIR ON SAN JOAQUIN RIVER. FLOOD CONTROL BY RESERVOIR OPERATING DIAGRAM. Carried out on a Daily Basis. mary, see Table 9, page 134.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.P. = 0.80. Coordinated with flood control by reservoir operating diagram Maximum controlled flow at Friant — rain-water flond.s, 10,700 see.-ft.: snow-water floods. 14,200 sec.-ft. Maximum re3erv>.ir space reiuired— rain-water floods, 133,000 ac.-ft.; now-water floods, 177,000 ac.-ft. Rtage of reservoir at beginning Irrigation Average draft in acre-feet Power Release through flood control outleta in aere-feet Waste Deficiency power head Average power Year and month (no deduction Evapora- tion in draft through over spillway in irrigation supply in acre-feet through period yield in kilowatts of month in acre-feet for down- stream prior acre-feet turbines in acre-feet in acre-feet of operation in (Load factor — 1.00) rights) feet 1924 436,600 Jan. 463,500 47,000 47,000 445 24,100 Feb 439,100 119,000 119,000 419 54,000 Mar 345,900 261,000 1,000 261,000 356 102,600 April 167,200 261,000 800 109,400 304 34,100 May 57,400 95,100 100 165,900 ,Iune 20,600 240,400 July 16,200 244,800 Aug. 12,700 2.33,300 Sept. 11,700 81,300 Oct. Nov. 27,800 « Dec. Total or average 844,300 1,900 536,400 955,700 394 17,800 1925 56,500 Jan. 83,600 47,000 Feb 114,400 119,000 Mar. 90,100 261,000 400 April 24,700 261,000 200 May 127,,50O 261,000 800 60,900 298 19,000 June 146,700 261,000 1,100 50,500 298 15,300 July 35,600 101,300 100 159,700 Aug. 37,100 198,900 Sept. 39,200 53,800 Oct. Nov. 38,900 Dec. Total or average 1,387,600 2,600 111,400 412,400 298 2,900 Total for 18-year period. 28,98^,500 219,800 25,010,400 3,530,700 442,500 3,415,500 1908-1926 Average for 18-year period. 1,610,300 12,200 1,389.500 196,100 24,600 189,700 484 61,400 1908-1926 342 WATER RESOURCES OF CALIFORNIA. TABLE 10a TEMPERANCE FLAT RESER COMPARISON OF WATER AND POWER YIELD Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Flood control by reservoir operating diagram Maximum controlled 3ow at Friant — rain-water floods, 10,700 sec.-ft.; snow-water floods, 14,200 sec.-ft. Maximum reser\-oir space required — rair -water floods, 133,000 ic.-ft.; snow-water floods, 177,000 ac.-ft. Run-off at Irrigation Year and month Friant in Stage of draft in Power Release Waste Deficiency .\verage power .\verage acre-feet reservoir at beginning of month in acre-feet acre-feet Evapora- tion in acre-feet draft through in head power yield in kilowatts (Load factor= 1.00) (no deduction for down- stream prior through turbines in acre-feet flood control outlets in acre-feet over spillway in acre-feet irrigation supply in acre-feet through period of operation in feet rights) 1908 Jan. 53,100 797,100 Keb. 58,100 850,200 47.000 47,000 548 29,200 Mar. 120,000 861,300 119.000 119,000 543 68,400 .\pril 199,000 862,300 261,000 1,700 261,000 5.30 152,400 May 219,000 798,600 261,000 2,200 261,000 522 145,800 June 176,000 754,400 261,000 2.600 261,000 507 146.900 July 119,000 666.800 261,000 2.800 261,000 478 135.100 Aug. 73,200 522,000 261,000 2.300 261,000 429 121.100 Sept. 39,000 331,900 236,000 1.300 228,100 347 86.800 Oct. 23,900 133,600 93,000 600 Nov. 16,200 63,900 200 Dec. Total or average 18,500 79,900 1,115.000 1,800,000 13,700 1,699,100 488 73,800 1909 Jan. 277.000 98,400 Feb. 183,000 375,400 47,000 47,000 438 24,700 Mar. 133,000 511.400 119,000 119,000 460 59.300 April May 352,000 525,400 261,000 1,300 261,000 459 134.200 646,000 615,100 261,000 1.900 266.400 86,700 529 150,300 June 827,000 906,100 261,000 2,900 273.000 484,800 553 164,400 July 309,000 972,400 261,000 3,600 263.900 34.400 568 150,600 Aug. 78,100 979,500 261,000 3.400 261.000 543 1.50,300 Sept. 37,000 793,200 236,000 2,300 236.000 500 131,400 Oct. 25,000 591,900 93,000 1,500 93.000 468 47,200 Nov. 49,600 522,400 900 Dec. 220,000 571,100 Total or average 3,136,700 1,800,000 17,800 1,820,300 C05.900 503 85,100 1910 Jan. 188,000 791,100 Feb. 86,600 979,100 47.000 87,600 900 567 57,600 Mar. 188,000 977,200 119,000 123,200 574 73,800 April May 375,000 1,042,000 261,000 1,900 262,200 33,800 66,500 576 162.600 475,000 1,052,600 261,000 2,700 280,900 328.800 556 164.400 June 237,000 915,200 261,000 2,900 263,300 37.800 547 157.400 July 99,600 848,200 261,000 3,300 261,000 520 145.200 Aug. 39,600 683,500 261,000 2,700 261,000 469 132.700 Sept. 51,700 459,400 236,000 1,600 236,000 398 104.900 Oct. 29,600 273,500 93.000 900 93,000 357 35,500 Nov. 24,000 209.200 500 Dee. Total or average 31,400 232,700 1,825,500 1,800,000 16,500 1,868,200 401,300 66,500 506 86,200 1911 Jan. 239,000 264,100 Feb. 207,000 503,100 47,000 47,000 489 27.500 Mar. 336,000 663.100 119,000 119,000 525 66.700 April May 425,000 880.100 261,000 1.800 261,000 561 158,900 571,000 1.042.300 261,000 2.600 280,000 4.30,500 557 164,000 Juno 946,000 900.200 261,000 2.900 272.300 541,900 555 164,400 July 593,000 1.029.100 261,000 3.700 273.100 203,700 74,600 574 163.300 Aug. 116,000 1.067.000 261,000 3.500 261.000 569 15.S.200 Sept. 45.500 918.500 236,000 2.400 236.000 532 138.200 Oct. 32,300 725.600 93,000 1,600 93.000 507 50,700 Nov. 28,000 663.300 1,000 Deo. Total or average 23,400 690.300 3,562,200 1,800,000 19,500 1.842,400 1.176,100 74,600 542 91,000 THE CONTROL OF FLOODS BY RESERVOIRS. VOIR ON SAN JOAQUIN RIVER. 348 FOR TWO METHODS OF FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 10, page 13b.) supply in years of deficiency. No deduction for downstream prior rights. ) Installed capacity of power plant 400,000 k.v.a. P. F. = 0.80. Flood control, holding maximum space required (rain-water floods, 133,000 ac.-ft.; siow-water floods, 177,000 ac.-ft.) In reserve throughout flood season Maximum controlled flow at Friant— rain-wa erflaoda, 10 ,700sec.-ft.; snow-water floods. 14,200 sec.-ft. Irrigation Stage of reservoir at beginning of month in acre-feet draft in acre-feet Evapora- tion in acre-leet Power draft Release through Waste Deficiency in .\verage power head .\verage power yield in kilowatts (Load factor= 1.00) Year and month (no deduction for down- stream prior through turbines in acre-tee t flood control outlets in acre-feet over spillway in acre-feet irrigation sjpply in acre-feet through period of operation in feet rights) 1908 797,100 Jan. 850,200 47,000 47,000 548 29,200 Feb. 861,300 119,000 119,000 543 68,400 Mar. 862,300 261,000 1,700 261,000 530 152,400 April 798,600 261,000 2.200 261,000 .522 145,800 May 754,400 261,000 2,600 261,000 507 146,900 June 666,800 261,000 2.800 261,000 478 135,100 July 522,000 261,000 2..300 261,000 429 121,100 Aug. 331,900 236,000 1,300 228,100 347 86,800 Sept. 133,600 93,000 600 Oct. 03,900 200 Nov. 79,900 Dec. Total or average 1,800,000 13,700 1,699,100 488 73,800 1909 98,400 Jan. 375,400 47,000 47,000 438 24,700 Feb. 511,400 119,000 119,000 460 59,300 Mar. 525,400 261,000 1,300 261,000 459 134.200 April 615,100 261,000 1,900 269,000 96,200 527 151,500 May 894,000 261,000 2,900 274,800 549,.300 548 164,400 June 894,000 251,000 3,400 272,200 79,000 544 156,900 July 848.400 261,000 3,100 261,000 516 144,400 Aug. 662,400 236,000 2,000 236.000 466 123,300 Sept. 461,400 93,000 1,200 93,000 430 43,300 Oct. 392,200 700 Nov. 441,100 Dec. Total or average 1,800,000 16,500 1,833,000 624,.500 488 83,700 1910 661,100 Jan. 849,100 47,000 47,000 552 30,400 Feb. 888,700 119,000 138,700 555 81,200 Mar. 938,000 261,000 1,800 262,400 76,500 558 159,000 .\pril 972,300 261,000 2,.500 285,500 265,300 544 164,400 May 894,000 261,000 2,900 263,600 35,700 542 150,700 June 828,800 261,000 3,300 261,000 514 144,000 July 664,100 261,000 2,600 261,000 463 131,000 Aug. 440,100 236,000 1,600 236,000 396 104,200 Sept. 254,200 93,000 800 93,000 344 34,000 Oct. 190.000 500 Nov. 213,500 Dec. Tnt'il nr 1,800,000 16,000 1,848,200 377,500 496 83,900 1 UUll Ul average 1911 244,900 Jan. 483,900 47,000 47,000 484 27,200 Feb. 643,900 119,000 119,000 .520 66,.30O Mar. 860,900 261,000 1,700 262,400 76,500 555 158,.500 April 945,300 261,000 2,500 286,000 333,800 543 164,400 May 894,000 261,000 2,900 272,700 540,100 554 164,400 June 1,024,300 261,000 3,700 270,000 287,200 568 160,400 July 1,056,400 261,000 3,500 261,000 566 154,800 Aug. 907,900 236,000 2,400 236,000 529 137,500 Sept. 715,000 93,000 1,600 93,000 504 50,400 Oct. 652,700 1,000 Nov. 679,700 Dec. Total or average 1.800,000 19,300 1,847,100 1,237,600 536 90,600 344 WATElt RESOURCES OF CALIFORNIA. TABLE 10a (Continued). TEMPERANCE FLAT COMPARISON OF WATER AND POWER YIELD Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Flood control by reservoir operating diagram Maximum control cd flow at Friant — rain-witer floods. 10,700 see.-ft.; snow-wate fljcds, 14,21)0 sec. -It. Maximum reservoir space required — rait -water floods. 133,000 ac.-ft.; IlllM-off snow-water floods, 177 ,000 ac.-ft. at Irrigation Year and month Friant in Stage of draft in Power Release Wa.^te Deficiency Average power Average acre-feet reservoir at beginning acre-feet Evapora- draft through in head power (no through flood over spillway irrigation through yield in deduction tion in ac.-e-feet turbines control supply period kilowatts 01 montti in acre-feet for down- stream prior in acre-feet outlets in acre-feet in acre-feet in acre-feet of operation in feet (Load factor^^ 1.00) rights) 1912 Jan. 30,100 713,700 Feb. 26,600 743,800 47,000 47,000 52i 28,000 Mar. .55,200 723,400 119,000 119,000 505 64,700 April 75,000 659,600 261,000 1,500 261,000 468 136,700 May 255,000 472,100 261,000 1,600 261,000 431 121,800 June 368,000 464,500 261,000 1,900 261,000 472 137,900 July 95,300 569,600 261,000 2.600 261,000 445 125,800 Aug. 38,000 401,300 261,000 1,900 261,000 367 102,700 Sept. 22,400 176,400 198,100 700 39,300 37,900 305 12,800 Oct. 17,800 17,800 75,200 Nov. 20,300 Dec. Total or average 20,000 20,300 1,023,700 1,686,900 10,200 1,510,300 113,100 454 60,900 1913 Jan. 22,100 40,300 Feb. 25,700 62,400 47,000 Mar. 38,200 41,100 79,300 39,700 April 95,800 95.800 165,200 May 247,000 219,200 41,800 June 170,000 27,800 197,700 100 63,300 July 102,000 102,000 159,000 Aug. 68.900 68,900 192.100 Sept. 40,600 40,600 195.400 Oct. 12,800 12,800 802,000 Nov. 22,300 Dec. Total or avrrage 28,700 22,300 874,100 863,300 100 930,700 1914 Jan. 259,000 51,000 Feb. 14.5,000 310,000 47,000 47,000 404 22,800 Mar. 234,000 408,000 119,000 119,000 439 56,600 April May 395,000 523,000 261,000 1,300 261,000 475 138.800 577,000 655,700 261.000 2,000 264,300 66,800 519 146,800 June 607.000 899,600 261,000 2,900 275,100 2t)4,900 547 164,400 July 392,000 963,700 261,000 3,600 265,000 26,200 574 158.600 Aug. 142,000 1,060,900 261,000 3,.500 261,000 573 1.56,100 Sopt. 53,900 938,400 236,000 2,500 236,000 537 139,000 Oct. 40,300 753,800 93,000 1,700 93,000 513 51,200 Nov. 30,500 699,400 1,100 Dec. ToUl or averaiEC 20,600 728,800 2,905,300 1,800,000 18,600 1,821,400 357,900 510 86,400 1915 Jan. 38,2(X) 758.400 Feb. 90,000 796,600 47,000 47,000 537 29,600 Mar. 124,000 839,600 119,000 119,000 .537 67.900 .^i)ril May 246,000 844,600 201,000 1,700 261,000 .532 152,800 381,000 827,900 261,000 2„300 264,100 44,300 538 151,100 June 580,000 898,200 261,000 2.900 275,200 241. .300 547 164.400 July 287,000 964,800 261,000 3,600 263,300 2,100 568 1,56,500 Aug. 70.100 082,800 201,000 3.400 261,000 545 1.50,700 Sept. 44,300 788.500 236,000 2,300 236,000 500 131,400 Oct, 26.700 594,500 93,000 1,500 93,000 466 47,000 Nov. 23.400 62»«,700 900 Dec. Total or 37.900 549,200 average 1,054,600 1,800,000 18,600 1,819,600 287,700 530 87,800 THE CONTROL OF FLOODS BY RESERVOIRS. 345 RESERVOIR ON SAN JOAQUIN RIVER. FOR TWO METHODS OF FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 10, page 13b.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.F. =0.80. Flood control, holding maximum space retiulred (rair-water floods, 133.000 ac. ft.; snov -water fiooJs, 177.000 ac.-/t.) in reserve through )ut flood season Maximvira controlled flow at Friaiit — raiii-witor floods, 10, 700soc.-ft.; snow-water floutls, 14,201 sec.-ft. Irrigation draft Average Average Year ami Stage ol in Power Release W-iste over spillway in acre-feet Deficiency power month reservoir at beginning of month in anre-feet acre-feet (no deduction for down- stream prior Evapora- tion in acre-feet draft through turbines in acre-feet through fljod control outlets in acre-feet in irrigation supply in acre-ieet head through period of operation in feet power yield in kilowatts (Load factor -^ 1.00) rights) 1912 703,100 .Ian. 733,200 47,000 47,000 sis 27,900 Feb. 712,800 119,000 119,000 502 64,400 Mar. 649,000 261,000 1,500 261,000 464 135,600 April 461,500 261,000 1,600 261,000 427 120,600 May 453,900 261,000 1,900 261,000 468 136,800 ,fune 559,000 261,000 2,500 201,000 441 124,700 July 390,800 261,000 1,900 261,000 361 101,100 Aug. 165,900 187,700 600 23,600 48,300 302 7,500 Sept. 17,800 75,200 Oct. Nov. 20,300 Dec. Total or average 1,676,500 10,000 1,494,600 123,500 4.54 59,900 1913 40,300 Jan. 62.400 47.000 Feb. 41,100 79,300 39,700 Mar. 95,800 165,200 April 219,200 41,800 May 27,800 197,700 100 63,300 June 102,000 159,000 July 68,900 192,100 Aug. 40,600 195,400 Sept. 12,800 80,200 Oct. Nov. 22,300 Dec. Total or average 863,300 100 936,700 1914 51,000 Jan. 310,000 47,000 47,000 404 22,800 Feb. 408,000 119.000 119,000 439 56,600 Mar. 5'i3,000 261,090 1,300 261,000 475 138,800 .\pril 655,700 261,000 2,000 265,100 71,600 519 147,200 May 894,000 261,000 2,900 277,100 327.000 542 164,400 June 894,000 261,000 3,400 272,900 98,800 547 157,900 July 910,900 261,000 3,200 261.000 541 149,700 Aug. 788,700 236,000 2,.300 236,000 502 131,900 Sept. 604, .300 93,000 1,500 93,000 474 47,800 Oct. 550,100 900 Nov. 579,700 Dec. Total or average 1,800,000 17,500 1,832,100 497,400 495 85,000 1915 609,300 Jan. 647,500 47,000 47,000 502 28,100 Feb. 690.500 119,000 119,000 503 64,400 Mar. 695,500 261,000 1.500 26 1.000 497 144,600 ,\pril 679,000 261.000 2,000 261,000 50ti 142,100 May 797.000 261,000 2.700 273,200 213,100 541 1 6 1.900 June 894.000 261,000 3.400 271,800 45.300 545 15t:..900 July 860,500 261,000 3.100 261,000 529 147,200 Aug. 666,500 236,000 2,000 236,000 468 123,800 Sept. 472,800 93,000 1,200 93,000 433 43,.500 Oct. 405,300 800 Nov. 427,900 Dec. Total or 1,800,000 16,700 1,823,000 258,400 503 84,000 average 22^52411 346 WATER RESOURCES OF CALIFORNIA. TABLE 10a (Continued). TEMPERANCE FLAT COMPARISON OF WATER AND POWER YIELD Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. riood control by reservoir operating diagram Maximum controlled flow at Friaiit— rai 1-water floods, 10,700 ec.-ft.; snow-water floods, 14.200 sec.-ft. Maximum reservoir space re:iuired — rair -water floods, 133,000 ac.-ft.; snow-water floods, 17 '.OOOac.-ft. Run-off at Irrigation Year and Fnant Stage of reservoir at beginning of month in acre-feet draft Average .\veragc power yield in kilowatts (Load factor— 1.00) month in acre-feet in acre-feet Evapora- tion in acre-feet Power draft Release through Waste Deficiency in pawer head (no deduction for down- stream prior through turbines in acre-feet flood control outlets in acre-feet over spillway in acre-feet irrigation supply in acre-feet through period of operation in feet rights) 1916 Jan. 173,000 587,100 Feb. 142,000 760,100 47,000 47,000 5.32 28,400 Mar. 338,000 855,100 119,000 122,100 562 72,000 April 477,000 1,071,000 261,000 2,000 264.300 210.700 579 164,400 May 552.000 1,071,000 261,000 2.700 280,100 417.600 21,500 558 164.400 June 572,000 901,100 261.000 2,900 274,000 226,600 549 164,300 July 289,000 969,600 261,000 3.600 261.000 569 l.i5.400 Aug. 91,000 994,000 261,000 3.400 261,000 551 151,700 Sept. 44,900 820,600 236.000 2..300 236.000 509 133.300 Oct. 63,900 627,200 93,000 1..500 93,000 486 48,900 Nov. 38,900 596,600 1,000 Dec. Total or average 45,300 634,500 2,827,000 1,800,000 19,400 1,838,500 644,200 232,200 544 90,.300 1917 Jan. 47.500 670,800 Feb. 129,000 727,300 47.000 47,000 519 28.900 Mar. 108,000 809,300 119,000 119,000 531 67,300 April 226,000 798,300 261,000 1.700 261.000 518 149,700 May 373.000 701,600 261.000 2,200 261.000 .530 147.400 June 579,000 871,400 261,000 2,800 262,900 57,600 56.100 569 161.400 July 222,000 1,071,000 261,000 3.800 264,200 13,100 579 159,100 Aug. 72,600 1,011.900 261.000 3.400 261,000 553 152.200 Sept. .36.100 820,100 236,000 2,300 236,000 507 1,33,200 Oct. 25,400 617,900 93,000 1,,500 93,000 477 48,000 Nov. 21,900 548,800 900 Dec. Total or average 19,600 569,800 1,860,100 1,800,000 18,600 1,805,100 57,600 69,200 532 87,500 1918 Jan. 20.500 589,400 Feb. 36.800 609,900 47,000 47,000 484 27.200 Mar. 140,000 599,700 119,000 119,000 483 62,200 April May 179,000 829,700 261,000 1,400 261.000 477 139,300 307,000 546,300 261,000 1,800 261,000 470 132,900 June 494,000 590,500 261,000 2,200 261,000 510 147,800 July 121.000 821,300 261,000 3,400 261,000 517 144,600 Aug. 42,800 677,900 261.000 2.700 261.000 467 132,100 Sept. 48,700 457,000 236,000 1,600 236,000 403 106,100 Oct. 103,000 298,100 93,000 900 93,000 382 38,300 Nov. 44,000 277,200 600 Dec. Total or average 50,700 320,600 1,596,500 1,800,000 14,600 1,800,000 466 77.700 1919 Jan. 38,400 371,300 Feb. 08,900 409,700 47,000 47,000 430 24,300 Mar. 94,100 431,600 119,000 119,000 427 55,000 April May 209,000 406,700 261.000 1,100 261,000 407 118.600 441,000 3.W,600 261,000 1.300 261,000 430 121.500 June 154,000 532,300 261,000 2,100 261,000 447 130,600 July 61,500 423.200 261,000 2,100 261,000 389 109,500 Aug. 30,400 221,600 250,300 1,700 92,600 10,700 320 30,800 Sept. 23,000 23,000 213,000 Got. 22,400 22,400 70,600 Nov. 18,600 Deo. Total or 30,100 18,600 average 1,191,400 1,505.700 8,300 1,302,600 294,300 416 49,200 THE CONTROL OP FLOODS BY RESERVOIRS. 347 RESERVOIR ON SAN JOAQUIN RIVER. FOR TWO METHODS OF FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 10, page 13fci.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P. F. =0.80. Flood con rol, holding maximum space required (rain-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac.-ft.) In reserve throughout flood season Maximum controlled flow at Friant— rain-water floods, 10 700 seo.-ft ; 3now-witer floods, 14,200 sec.-ft. Irrigation Stage of reservoir draft in acre-feet Evapora- tion in acre-ieet Power draft Release through Waste Defieieney in Average power head Average power yield in kilowatts (Load factnr= 1.00) Year and month at beginning of month in acre-feet (no deduction for down- stream prior through turbines in acre-feet flood control outlets in acre-feet over spillway in acre-feet irrigation supply in aere-teet through period of operation in feet rights) 1916 465.800 .Ian. 638,800 47,000 47,000 504 27,300 Feb 733.800 119,000 129,400 4.400 .536 73,800 Mar. 9.38,000 261.000 1,800 264,100 108,700 4,200 566 161,900 April 1,036.200 261,000 2,600 282,900 408,700 551 164,400 May 894,000 261,000 2,900 276,900 292,200 542 164,400 .lune 894,000 261.000 3,400 272,600 38,100 546 157,400 July 868,900 261,000 3,100 261,000 524 146,100 .\ug. 695.800 236,000 2,100 236,000 476 125,800 Sept. 502,600 93,000 1.300 93,000 451 45,400 Oct. 472.200 800 Nov. 510,300 Dee. Totiil or average 1,800,00 18000 1,862,900 852,100 4,200 522 89,000 1917 555,600 Jan. 603,100 47,000 47,000 489 27,500 Feb. 685,100 119,000 119,000 502 64,400 Mar. 674,100 261,000 1,500 261,000 488 142,400 April 637,600 261,000 2,000 261,000 501 140,900 May 747,600 261,000 2,600 270,500 159,500 537 159,400 June 894,000 261,000 3,400 267,400 10,000 544 154,000 July 835,200 261,000 .3,100 201,000 .536 148,900 Aug. 643,700 236,000 2,000 236,000 461 121,800 Sept. 441,800 93,000 1,200 93,000 422 42,500 Oct. 373,000 700 Nov. 394,200 Dec. Total or average 1,800,000 16,.500 1,815,900 160,.500 498 83,700 1918 413,800 Jan. 434,300 47,000 47,000 4,32 24,400 Feb. 424,100 119,000 119,000 431 55,.500 Mar. 4.54,100 261,000 1,200 261,000 422 122,900 April 370,900 261.000 1.400 261,000 415 117,100 May 415,500 261,000 1,800 261,000 464 1.35,600 June 646,700 261.000 2.800 261,000 473 133.600 July 503,900 261.000 2.200 261,000 411 116,000 Aug. 283,500 236,000 1,200 17.3,100 334 63,100 Sept. 95.000 93,000 400 18,000 296 5,400 Get. 104,600 300 Nov. 148,300 Dec. Total or average 1,800,000 11,300 1,662,100 423 64,600 1919 199,000 Jan. 237,400 47,000 47,000 360 20,100 Feb. 259,300 119,000 119,000 357 45,400 Mar. 234,400 261,000 800 261,000 333 94,600 April 181,600 261,000 900 261,000 363 101,600 May 360,700 261,000 1.600 261,000 .386 112,400 June 252,100 261,000 1.500 151,500 328 52,200 July 51,100 81,400 100 179,600 Aug 23,000 213,000 Se )t. 22,400 70,600 Oct. Nov. 18,600 Dec. Totsl or average 1,336,800 4,900 1,100,.500 463,200 357 35,,500 348 WATER RESOURCES OF CALIFORNIA. TABLE 10a (Continued). TEMPERANCE FLAT COMPARISON OF WATER AND POWER YIELD Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Flood control by reservoir operatino diagram Maximum coiitroll id flow at I runt— rail -water ttiiods. 10.700 sec.-ft.; snow-water fijods, U, OJsec-ft. Maximum reservoir space required — rair. -watei fljcds, 133.000 ac.-it.; now-water floods, 177 000 ac-ft. Run-off at Irrigation Year and iii(j".th Friant in acre-ieol Stage of •eiervoir drift in acre-fee. Power dr.ft Rele se through Waste De5cie;:cy in .Average power head .\vor:'ge power yield in kibwatts (Load factor- 1.00) at >eginning 01 month in i(ire-feet (no deduction for down- stream prior Evapora- tion in ■icre-feet through tur'iines in acre-feet fljod control outlets in acre-feet O'er spillway in acre-feet i rigatiui supply in acre-feet through period oi oper tion in feet rights) 1920 Jan. 20,900 48,700 Feb. 28.900 75,600 47,000 Mar. 101,000 57,.500 119,000 April 161,000 39,500 198.000 63,000 May 407,000 2,500 253,600 8,400 1,400 298 2,600 June 327,000 149,900 261,000 900 261,000 336 95,700 July 111,000 215,000 261,000 1,400 151,500 320 50,500 Aug. 45,400 63,600 108,900 100 152,100 Sept. 29,200 29 200 206,800 Oct. 37,000 37,000 56,000 Nov. 44,600 Dec. Total or average 43.000 44,600 1,362,000 1,320,700 2,400 420,900 479,300 329 12,300 1921 Jan. 67,600 87,600 Feb. 77,800 155,200 47,000 47,000 317 17.100 Mar. 162,000 186,000 119,000 119,000 340 42,900 April 18'.),000 220,000 261,000 700 261,000 322 90,700 May 323,000 156,300 261.000 800 261.000 324 88,400 June 407,000 217.500 201,000 1.200 261,000 379 110,100 July 155,000 362.300 261,000 ! ,400 261,000 390 109,900 Aug. 51,600 254,900 261,000 1,400 151,500 327 52,000 Sept. 34,700 44,100 78,700 100 1.57,300 Oct. 26,300 26,300 66,700 Nov. 23,000 Dec. Total or average 63,300 23,000 1,. 580,300 1,576,000 5,600 1,361,500 224,000 344 42,700 1922 Jan. 67,600 86,300 Feb. 96.100 153,900 47,000 47,000 32 i 17.400 Mar. 103,000 203,000 119,000 119,000 328 41,000 April May 19.?,000 187,000 261,000 700 130.500 308 42.8(X) 621,000 118,300 261,000 700 244,200 367 96,200 June 732,000 477,600 261,000 1,900 201,000 512 145,300 July 270,000 946,700 261.000 3.000 261,000 565 154,600 Aug. 84,800 9,52,100 261,000 3,000 261,000 542 150.000 Sept. 43,400 772,300 236,000 2,200 230,000 498 131.000 Oct. 31,900 577,500 93,000 1,400 93,000 466 46,900 Nov. 42.400 515,000 900 Dec. 91,600 556,500 Total or average 2,370,800 1,800.000 15,000 1,652,700 c 443 69.310 1923 Jan. 69,.5O0 648,100 Feb. 70,000 717,600 47,000 47,000 520 29.000 Mar. 95,900 740,600 1 19,000 119,000 513 65,000 April May 199,000 717,.5O0 201,000 1,600 261,000 ,500 14,5,400 450,000 653,900 261.000 2,000 261.000 261,000 513 143.800 June 287,000 840,900 261,000 2.800 538 1,54.200 July 201,000 864,100 261,000 3,300 261.000 539 149,500 Aug. 72.600 800,800 261,000 2,900 261,000 507 142,300 Sept. 50.900 609,500 230,000 1,900 236,000 453 110,900 Oct. 48,300 422,.5O0 93,000 1,200 93.000 420 42,200 Nov. 33,000 376,600 700 Dec. Total or 27,700 408,900 average 1,604,900 1.800,000 16,400 1,800,000 500 82,900 THE CONTROL OF FLOODS BY RESERVOIRS. 349 RESERVOIR ON SAN JOAQUIN RIVER. FOR TWO METHODS OF FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 10, page 13b.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P. F. = 0.80. Flood control, holding maximum space required (rair-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac.-ff.) in reserve through out flood season Maximum controlled flow at Friant— raiii-wa erfl3ods. 10,700 sec.-ft.; snow-water fliods, 14,200 sec.-ft. Irrigation Stage of draft in Power Release Waste over spillw.-iy in acre-feet Deficiency Average power Average Year and reservoir at leginniiig of month in acre-feet acre-feet (no deduction for down- stream prior Evapora- tion in acre-feet draft through turbines in acre-feet through flood control outlets in acre-feet in irrigation supply in acre-feet head through period of operation in feet power yield in kilowatts (Load factor= 1.00) month rights) 1920 48,700 Jan 75,600 47,000 Feb. 57,500 119,000 Mar. 39,500 198,000 63,000 April 2,500 259,600 8,400 1,400 298 2,600 May 119,900 261,000 900 261,000 336 95,700 June 215.000 261,000 1,400 151,500 320 50,500 July 63,600 108,900 100 152,100 Aug. 29,200 206,800 Sept. 37,000 56,000 Oct. Nov. 44,600 Dec. Total r.T average 1,320,700 2,400 420,900 479,300 329 12,300 1921 87,600 Jan. 155.200 47,000 47,000 3i7 17,100 Feb. 186,000 119,000 119,000 340 42,900 Mar. 229,000 261.000 700 261,000 322 90,700 April 156,300 261,000 800 261,000 324 88,400 May 217,500 261,000 1,200 261,000 379 110,100 June 362,300 261.000 1,400 261,000 390 109,900 Julv 254, f 00 261,000 1,400 151,500 327 52,000 Aug. 44,100 78,700 100 157,300 Sept. 26,300 66,700 Oct. n Nov. 23,000 Dee. Total or 1,576.600 5,600 1,361,500 224,000 344 42,700 average 1922 86,300 Jan. 153,900 47,000 47,000 321 17,400 Feb. 203,000 119,000 119,000 328 41,000 Mar, 187,000 261,000 700 130,500 308 42.800 April 118.300 261.000 700 244,200 367 96,200 Mav 477,600 261.000 1,900 263,600 50,100 510 148.900 June 894,000 261.000 3.400 270,600 41,300 544 156,100 Jiilv 848,700 261,000 3,100 261,000 518 144,900 Aug 669,400 238,000 2.000 230,000 470 124.300 Sept . 474,800 93,000 1,200 93,000 4.35 43,800 Oct. 412,500 800 Nov. 4.54,100 Dee. Total or average 1,800,000 13,800 1,664,900 91,400 431 68,200 1923 545,700 Jan. 615,200 47,000 47,000 494 27,800 Feb. 638,200 119,000 119,000 489 62,900 Mar 61.5,100 261,000 1,400 261,000 474 1.38,.500 April 551,700 261,000 1,800 261,000 488 137,800 May 738,900 261,000 2,600 261,000 516 149,300 June 702,.30O 261,000 3,100 261.000 520 145.300 July 099,200 261,000 2,700 261,000 480 135,.500 Aug, 508,100 236,000 1,700 236,000 420 1 10.800 Sept. 321,.30O 93,000 1,000 93,000 .381 38,200 Oct, 275.600 600 Nov, 308,000 Dee. Total or 1,800,000 14,900 1,800,000 473 79,000 average ;joO WATER KESOUKCES OF CALIFORNIA. TABLE 10a (Concludedj. TEMPERANCE FLAT COMPARISON OF WATER AND POWER YIELD Monthly Summary of Computations (For corresponding yearly sum Seasonal irrigation yield 1,800,000 acre-feet. (Supplemented by ground water Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Flood control by reservoir operating diagram Maximum control ';d flaw at Ftiiiit— rai ■--water floo ds, 10,700 sec.-ft.; snow-water floods, 14. 200scc.-ft. Maximum reservoir space required — rair -wUerflvids, 133,033 ac.-ft.; snow-water floods, 177,000 ac.-ft. Run-off at Irrigation Year and Friant Stage of reservoir at beginning of month in acre-feet draft Average Average power yield in kilowatts (Load factor=^ 1.00) month in acre-fee t in acre-feet (no deduction for down- stream prior Evapora- tion in acrc-fect Power draft through turbines in acre-feet Release through flood control outlets in acre-feet Waste over spillway in acre-feet Deficiency in irrigation supply in acre-feet power head through period of operation in feet rights) 1924 .Tan. 26,900 436,000 Fob. 22.600 463,500 47,000 47.000 445 24.100 Mar. 25,800 439,100 119,000 119,000 419 54,000 April 83,300 345,000 261,000 1,000 261,000 356 102.600 May 1.52,000 167,200 261,000 800 109,400 304 34,100 June 37.800 57,400 95,100 100 165,900 July 20,600 20,600 240,400 Aug. 16,200 16,200 244,800 Sept. 12,700 12,700 223,300 Oct. 11,700 11,700 81,300 Nov. 27.800 Dec. Total'Or average 28,700 27,800 466,100 844,300 1,900 .536,400 955,700 391 17,800 1925 Jan. 27,100 56,500 Feb. 77,800 83,600 47,000 Mar. 04,700 114,400 119,000 April 106,000 90,100 261,000 400 May 364,000 24,700 261,000 200 June 281,000 127,500 261,000 800 60,900 298 19.000 Jub' 1.51,000 146,700 261,000 1,100 5O,.5O0 298 15,300 AUR. 65,800 35,600 101,.300 100 159,700 Sept. .37,100 37,100 198,900 ... Oct. 39,200 30,200 53,800 Nov. 38,900 Dec. Total or average 40,800 38,900 1,41.3.400 1,387,600 2,600 111,400 412,400 298 2.900 Total for 18-year ppriod. 1908-1926 32,675,600 28,984,500 219,800 25.010,400 3,530,700 442,500 3,415,500 Average for 18-year period. 1908-1926 1.815,300 1,610,300 12,200 1,389,500 196.100 24.600 189,700 484 61,400 THE CONTROL OF FLOODS BY RESERVOIRS. 351 RESERVOIR ON SAN JOAQUIN RIVER. FOR TWO METHODS OF FLOOD CONTROL. Carried out on a Daily Basis. mary, see Table 10, page 13b.) supply in years of deficiency. No deduction for downstream prior rights.) Installed capacity of power plant 220,000 k.v.a. P.F. = 0.80. Flood con trol, holding maximum space required (rain-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac.-ft.) in reserve throughout flood season Maximum controlied flow at Fria nt — rain-water floods, 10,700 aec.-ft.; snow-water floods, 14,200 sec.-ft. Irrigation Stage of reservoir draft Average Average power Year and in acre-feet Power draft Releiise through Waste Deficiency in power head month at beginning of month in acre-feet (no deduction for down- stream prior rights) Evapora- tion in acre-tect through turbines in acre-feet flood control outlets in acre-feet over spillway in acre-teet irrigation supply in acre-feet through period of operation in feet yield in kilowatts (Load factor---- 1.09) 1924 335,700 .Jan. 302,600 47,000 47,000 409 22,300 Feb. 338,200 119,000 1 19,000 380 48,700 Mar. 245,000 261,000 800 147,900 323 51,500 April 66,500 218,200 300 42,800 May 37,800 22.3,200 .June 20,600 240.400 .Julv 16,200 244,800 Aug. 12,700 223,300 Sept. 11,700 81,300 Oct. Nov. 27,800 Dec. Total or average 744,200 1,100 313,900 1,055,800 378 10,100 1925 56,500 .Ian. 83,600 47,000 Feb. 114,400 119,000 M..r. 90,100 261,000 400 April 24,700 261,000 200 May 127,500 261,000 800 60,900 298 19,000 .lune 146,700 261,000 1,100 50,500 298 15,300 .lulv 35,600 101,300 100 159,700 Aug. 37,100 198,900 Sept. 39,200 53,800 Oct. Nov 38,900 Dee. Total or average 1,387,600 2,600 111,400 412,400 298 2,900 Total for 18-year 28,705,100 200,900 24,491,100 4,208,400 4,200 3,694,900 period. 1908-1926 Average for 18-yoar period, 1908-1926 1,594.700 11,200 1,360,600 233,800 200 205,300 467 58,300 352 WATER RESOURCES OF fALll'OKMA. TABLE Ua. TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 9a and 10a. (For corresponding yearly summary, see Table 11, page 138.) Height of dam 595 feet. Capacity of reservoir 1.071.000 acre-feet. Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P. F. =0.80. Coordinated with flood control by ressrvoir operating diagram Maximum controlled flow at Friiut — rain-water floods. 10.700 sec.-ft.; snow-water floods, 14.200 sec.-ft. Flood control, holding maximum reservoir space required i rain-water floods. 133.000 ac.-ft.; snow-water floods. 177.000 ac.-ft.) in reserve Without flood control throughout f^ood season Maximum reservoir space required — rain-water floods, 133,000 ac.-ft.: snow-water floods, 177,000 ac.-ft. Maximum cnntr.-illed flow at Friant — rain-water floods. 10.700 sec.-ft.: snow-water floods. 14.200 sec.-ft. Yfear and month Irrigation Irrigation Irrigation draft in acre-feet Deficiency .Average power draft in acre-feet Deficiency .Average power draft in acre-feet Deficiency .\veragc power fno deduction in irrigition supply jield in kilowatts (no deduction in irrigation supply yield in kilowatts (no deduction in irrigation supply yield in kilowatts for down- (Load for down- (Load for down- (Load stream prior in acre-feet factor= 1.00) stream prior in acre-feet factor= 1.00) stream prior in acre-feet factor= 1.00) rights) rights) rights) 1908 Jan. Feb. 47.000 29.200 47,000 29,200 47.000 29.200 Mar 119,000 68.400 119.000 68,400 119.000 68.400 April 261.000 152.400 261.000 152,400 261.000 152,400 May 261.000 145,800 261,000 145.800 261,000 145.800 Jane 261.000 146.900 261,000 146.900 261.000 146.900 July 261.000 135.100 261,000 135.100 261.000 135.100 Aug. 261,000 121.100 261.000 121,100 261.000 121.100 Sspt. 236,000 86,800 236.000 86,800 236.000 86.800 Oct. 93,000 93,000 93.000 Nov. Dec. Total or average 1.800,000 73,800 1.800.000 73.800 1.800.000 73.800 1909 Jan. Feb 17.000 24.700 47.000 24.700 47.000 24.700 Mar. 119.000 .59,300 119.000 59.300 119.000 59..300 April 261,000 1.34.200 261.000 134.200 261,000 1.34.200 May 261.000 147,700 261.000 150.300 261,000 151. .500 June 261,000 164.200 261,000 164.400 261.000 164.400 July 261.000 161.000 261.000 156.600 261.000 156.900 Aug. 261.000 152.400 261,000 150.300 261.000 144.400 •Sept. 236.000 1.34.200 236,000 131.400 236.000 123.300 Oct. 93.000 48.500 93,000 47.200 93.000 43,300 Nov. .0 IVc. Total or ovrragc 1.800.000 85.800 i. 800,000 85.100 1.800.000 83,700 1910 Jan. Feb. 47.000 31.500 47,000 57.600 47.000 30.400 Mar. iin.ooo 109.7(K) 119.000 73.800 119.000 81.200 April May 261.000 163..5f)0 261.000 162.600 261.000 1.59,000 261.000 164.400 261. COO 164.400 261.000 164,400 June 261,000 162.600 261.000 157.400 261,000 156.700 July 261.000 1J2.300 261.000 145.200 261.000 144,000 Aug. 261.000 142.900 261.000 132.700 261.000 131.000 .Sept. 236.000 120.400 236.000 104.900 236.000 104.200 Oct. 93,000 42,200 93.000 35.500 93.000 34,000 Nov. I>ec. 'I'otal or avi-r.ige 1.800.000 91.100 1.800.000 86.200 1,800.000 83.9C0 THE CONTROL OF FLOODS BY RESERVOIHS. 353 TABLE 11a (Continued). TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 9a and 10a. (For corresponding yearly summary, see Table 11, page 138.) Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P.F. = 0.80. Coordinated with flood control by reservoir operating dligram Maximum 3 )ntrolled flow at Friant — rain-water floods, 10,700 sec.-ft.; snow-water floods, 14,200 sec.-ft. Flood control, holding maximum reservoir space required (rain-water floods, 133,000 ac.-ft.; snow-water floods, 177,000 ac.-ft.) in reserve Without flood control throughout flood season Maximum r jservoir space re'i aired— rain-water floods. 133,030 ac.-ft.; snow-water flaods, 177,000 ac.-ft. Maximum c )ntrolIed flow at Friant-rain-water floods, 10,700 sec.-ft.; snow-water Hoods, 14,200 sec.-ft. Year and month Irrigation Irrigation Irrigation draft in acre-feet Deficiency Average power draft in acre-feet Deficiency Average power draft in acre-feet Deficiency Average power (no deduction irrigation supply yield in kilowatts (no deduction in irrigitiou supply yield in kilowatts (no deduction in irrigation supply yield in kilowatts for down- (Load for down- (Load for down- (Load stream prior in acre-feet factor= 1.00) stream prior in acre-feet factor= 1.00) stream prior in acre-feet factor= 1.00) rights) rights) rights) 1911 .Ian. Feb. 47,000 29,200 47,000 27,500 47,000 27,200 Mar. 119,000 69,900 119,000 66,700 119,000 66,300 April 261,000 164..300 261,000 158,900 261,000 1.58,500 May 261,000 164,400 261,000 164,000 261,000 164,400 June 261,000 164,400 261,000 164,400 261,000 164,400 July 261,000 163,400 261,000 163,300 261,000 160,400 Aug. 261,000 155,200 261,000 155,200 261,000 154,800 Sept. 236,000 138,200 236,000 1.38,200 236,000 137,500 Oct. 93,000 50,700 93,000 50,700 93,000 50,400 Nov. Dec. Total or average 1,800,000 91,900 1,800,000 91,000 1,800,000 90,600 1912 Jan. Feb. 47,000 28.000 47.000 28,000 47,000 27,900 Mar. 119,000 64,700 119,000 64,700 119,000 64,400 April 261,000 136,700 261,000 136,700 261,000 135,600 May 261,000 121.800 261,000 121,800 261,000 120,600 June 261,000 137,900 261,000 137,900 261,000 136.800 July 261,000 12.^800 261,000 125.800 261,000 124,700 Aug. 261,000 102,700 261,000 102,700 261,000 101,100 Sept. 198,100 37,900 12,800 198,100 37,900 12,800 187,700 48,390 7,500 Oct. 17,800 75,200 17,800 75,200 17,800 75,200 Nov. Deo. Total or average 1,686,900 113,100 60,900 1,686,900 113,100 60,900 l,676,.'i00 123,500 59,900 1913 Jan. I) Feb. 47,000 (1 47,000 47,000 Mar. 79,300 39,700 79.300 3!l,700 79.300 39,700 April 9.5,800 165,200 95.800 165,200 95,800 165,200 May 219,200 41.800 219,200 41,800 219,200 41,800 June 197,700 ()3,30n 197.700 (i3.300 197,700 63,300 July 102,000 I. =19,000 102,000 159,001) 102.000 15.),000 Aug. 68.900 192,100 68.900 192,100 68.900 192,100 Sept. 40,600 195,400 40,600 195,400 40.000 195,400 Oct. 12 800 80,200 12,800 80.2(M) 12,800 80,200 Nov. Dec. Total or average 863,300 863,300 936,700 883,,300 033,700 933,700 354 WATER RESOURCES OF CALIFORNIA. TABLE Ua (Continued). TEMPERANCE FLAT RESERVOIR ON SAN JOAQUIN RIVER. SUMMARY OF WATER AND POWER YIELD BY MONTHS BOTH WITH AND WITHOUT FLOOD CONTROL. Summary of Tables 9a and 10a. (For correspondng yearly summary, see Table 11, page 138.) Height of dam 595 feet. Capacity of reservoir 1,071,000 acre-feet. Seasonal irrigation yield, 1,800,000 acre-feet. (Supplemented by ground water supply in years of deficiency. No deduction for downstream prior rights). Installed capacity of power plant 220,000 k.v.a. P.F. = 0.80. Coordinated with flood control by Flood control, holding Tiaximum reservoir operating diagram Maximum controlled flow at reservoir space requiree (rain-water floods, 133,000 ac.-ft.; snow-water Friant — rain-water floods. floods, 177,000 ac.-ft.) n reserve Without flood control 10,700 sec.-ft.; snow floods, 14.200 sec -water -ft. throughout flood season Maximum controlled flow at Maximum reservoir space required — rain-water floods, 133,000 ac.-ft.: snow-water floods, 177,000 ac.-ft. Friant — rain-water 10,700 sec.-ft.; snow floods, 14,200 sec Joods. -water .-ft. Year and month Irrigation Irrigation Irrigation draft in acre-feet Deficiency Average power draft in acre-feet Deficiency Average power draft in acre-feet Deficiency Average power (no deduction in irrigation supply yield in kilowatts (no deduction in irrigation supply yield in kilowatts (no deduction in irrigation supply yield in kilowatts for down- (Load for down- (Load for down- (Load stream prior in acre-feet factor= 1.00) stream prior in acre-feet factor= 1.00) stream prior acre-feet factor= 1.00) rights) rights) rights) 1914 Jan. Feb. 47,000 22,800 47,000 22,800 47,000 22,800 Mar. 119,000 56,600 119,000 56,600 119,000 56,600 April 261,000 138.800 261,000 138.800 261.000 138.800 May 261.000 145,300 261,000 146,800 261,000 147,200 June 261,000 163,800 261,000 164.400 261.000 164,400 July 261,000 162„500 261,000 158,600 261,000 157,900 Aug. 261,000 156,100 261,000 156,100 261,000 149,700 Sept. 236,000 139,300 236,000 139,000 236.000 131,900 Oct. 93,000 51,300 93,000 51.200 93,000 47,800 Nov. Dec. Total or average 1,800,000 86,600 1,800,000 86,400 1,800,000 85,000 1915 Jan. Feb. 47,000 29,800 47,000 29,600 47,000 28,100 Mar. 119,000 68,100 119,000 67,900 119,000 64.400 April 261,000 153,100 261,000 152.800 261, (X)0 144.600 May 261,000 149,900 261,000 151,100 261.000 142.100 June 261,000 163,300 261,000 164,400 261.000 161.900 July 261,000 160,800 261,000 156,500 261.000 156,900 Aug. 261,000 153,000 261,000 150,700 261,000 147,200 Sept. 236,000 134.600 236,000 131,400 236.000 123.800 Oct. 93.000 48,800 93,000 (1 47,000 93.000 43,,500 Nov. Dec. Total or average 1,800,000 88,700 1,800,000 87,800 1,800,000 84,600 1916 Jan. Feb. 47.000 29,000 47,000 28.400 47,000 27,,300 Mar. 119.000 97,000 119,000 1 72,000 119.000 73,800 April 261,000 164.400 261,000 164,400 261,000 161.900 May 261,000 n lfi4.4(M) 261,000 164,400 261.000 164,400 June 261.000 164.400 261,(X)0 164,.300 261,000 164,400 July 261.0ptoinber 0.51 12.7 October o.-'io n.(; Xov.'inbcr 0.26 ti.". T..t:.ls 4.00 100.0 r ;{()() WATEi; KKSOl'IM'KS OF CALIFORXIA. TABLE 12a. SAN GABRIEL RESER WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood cor trol leserve or first 180,000 acre- 131,000 acre-feet of capacity Flood Flood control control Run-off at Azusa Passed water Passed water Year and m,)ntii Stage of reservoir by dam for prior rights pissing Azusa during Seasonally Evapora- tion from Waste Stage of reservoir by dam for prior rights passing Azcsa daring in at (■first 152 flood stored over spillway in acre-feet at beginning of month in acre-feet ffirst 152 flood acre-feet beginning of n.onth in ae re-feel second- fee t of ratural flaw) in season at rates less than 1,900 w^tcr in acre-feet reservoir surface in acre-feet second- feet of natural flow) in season at rates less than 1,900 acre-feet second- feet in acre-feet acre feet second- feet in acre-feet 1897 Jan. 3,fil7 3,617 . 3.617 Feb. IS), 146 7,262 4,913 7.262 Mar. 28.ti23 6,971 9,344 11.884 9.344 April 17,511. 26,250 9,042 4.164 131 31.163 9,042 May 8,8.51 3C,432 8,126 5,963 194 34,.53o 8.120 .June 4,033 25,000 4,033 5,985 206 28.236 4.033 (1 J lily 2,343 18,800 2,343 6.185 212 21,244 2.343 A,1K. 1,1)'? 12,412 1,613 6,185 149 14,020 1.613 Sept. 1,226 6,078 1,226 6.006 72 6,855 1.226 Oct. 5,564 2,622 2,622 Nov. 1,800 2,942 1,860 20 2,942 1.860 Dec. 1,875 2,922 1,875 2.922 1.875 Total or average 96,270 52,963 1.013 34,488 984 52,963 1898 .Jan. •2,453 2.922 2,453 2.922 2.453 Feb. 2,241 2,922 2.241 2,922 2.241 Mar. 2,131 2,922 2,131 2.922 2,131 April l,!»50 2,922 1,950 448 34 2,922 1,950 (1 May 2,213 2,440 2,213 462 39 2,440 2,213 June 1,1.5'.; 1,93!! 1,159 448 39 1.939 1.159 July 672 1,4.52 672 464 40 1.452 o72 Aug. 45fi 948 456 462 26 948 456 Sept. 467 460 467 44b 12 c 460 467 Oct. 5.33 533 533 Nov. .580 580 580 Dec. Total or average 832 832 832 15,o87 15,687 15,687 2.732 190 n 1899 Jan. 1, 114 1,414 1,114 n Feb. 1.244 1,244 t 1.244 (1 Mar. 1.623 1,623 1.623 April 1.262 1,262 1,262 May 842 842 842 (i June 565 565 o65 11 July 221 221 221 Auk. 205 295 295 (I Sept. 220 220 220 (1 Oct. 683 683 683 Nov. 847 847 847 (I Dec. 1,247 1,247 1,247 Total or averaKC 10.463 10,403 »l 10,463 i THE CONTROL OF FLOODS BY KESEKVOIRS. VOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 361 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre -feet capacity Flood control Passed water Seisonally stored Evapora- tion from Waste over spillway in acre-feet Stage of reservoir at beginning cf month in acre-feet by dam for prior rights (first 152 passing Azusa d.iring flood Seasonally stored Evapora- tion from Waste over Year and month water in acre-feet reservoir surface in acre-feet second- feet of natiiral flow) in season at rates less than 1,900 water in acre-feet reservoir Siirface in acre-feet spillway in acre-feet acre-feet second- feet in acre-feet 1897 3,617 Jan. n 7,262 Feb. 11,884 9,344 Mar. 4,y5S 147 31,163 9,042 4,958 147 April 6,814 210 34,535 8,126 6,814 210 May 6,770 999 28,236 4,033 6,770 222 June 6,996 228 21,244 2,343 6,996 228 . July 6,996 169 14,020 1,613 6,996 169 Aug. 6,770 85 6,855 1,226 6,770 85 Sett. 2,622 Oct. 20 2,942 1,860 20 Nov. 2,922 1,875 Dec. Total or average 39,304 1,081 52,963 39,304 1,081 1898 2,922 2,i53 Jan. 2,922 2,241 Feb. 2,922 2,131 Mar. 448 3* 2,922 1,950 448 34 April 462 39 2,440 2,213 462 39 May 448 39 1.939 1,159 448 39 June 464 40 1,452 6/2 464 40 July 462 26 948 456 462 26 -■Vug. 448 12 460 467 448 12 Sept. 533 Oct. 580 Nov. 832 Dec. Total or average 2,732 190 15,687 2,732 190 1899 1,414 Jan. (1 1,244 Feb. 1,623 Mar. 1,262 () April 842 May (1 565 June n 221 (1 July 295 Aug. 220 Sept. 683 n Oct. 847 Nov. 1,247 Dec. Total or average 10,463 ■.W2 NVATEI{ RESOURCES OF CALIFORNIA. TABLE 12a ^Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 180,000 acre- 131,000 acre-feet of capacity Flood Flood control control Run-off at Azusa Passed water Passed water Year and month Stage of reservoir tydam for nrior rights passing Azusa during Seasonally Evapora- tion from Waste Stage of reser^'oir by dam for prior rights passing .\zu8a during in acre-feet at beginning of month in acre-feet (first 152 second- flood season stored water in reservoir svirface in acre-feet over spillway at beginning of month in acre-feet (first 152 second- flood season feet of natural flow) in at rates less than 1.900 acre-feet in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet eecond- feet in acre-feet second- feet in acre-feet acre-feet 1900 Jan. 1,S68 1,968 1.968 Feb. I.IU 1,111 1,111 Mar. 1,230 1,230 1.230 April 1.012 1,012 1.012 May 2.275 2,275 2.275 June 893 893 893 July 369 369 369 Aug. 246 246 246 Sept. 238 238 238 Oct. 307 307 307 Nov. 11,068 1,058 1,058 Dec. Total or average 1,269 10,010 1,269 10,010 1.269 21,986 11,976 11.970 1901 Jan. 10.391 10,010 6,661 12,810 10,010 6,661 Feb. 38,709 930 8,350 19,884 13.740 8,3.50 Mar. 13,589 11,405 9,138 44,099 9,1.38 April May 6,545 15,856 6,545 2.499 99 48,550 6,545 7,440 13,258 6,990 2,582 117 tO,600 6,990 June 3,749 11,009 3,749 2,618 129 32,799 3,749 July 1,845 8,202 1,845 2,704 125 24,679 1.845 Aug. 1,240 5,433 1,240 2,704 79 16,295 1.240 Sept. 1,012 2,650 1.012 2,610 40 7.971 1.012 Oct. 1,476 1,476 1.476 Nov. 1,904 1,904 1.904 Dec. 1,600 1,660 1.660 Total or average 89,560 50.570 32.694 15,;i7 589 50.570 1902 Jan. 1,722 1,722 1.722 Feb. 2,055 2.055 2.055 (1 Mar. 6,088 5,590 5.590 April May 3,928 498 3,928 72 8 498 3.928 2,398 418 2,398 73 11 418 2.398 June 1,190 334 1,190 72 12 334 1.190 July 076 250 676 74 12 250 676 Aug. 430 164 430 74 12 164 430 Sept. 298 78 298 72 6 78 298 Oct. 430 430 430 Nov. 1,131 1,131 1.131 Dec. 1,968 1,968 1.968 Total or average 22.314 21,816 437 61 21,816 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. ''COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, sec Tabic 12, page 158.) 363 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet cppacity 240,000 acre -feet capacity Flood control Passed water Seasonally stored water in acre-feet Evapora- tion from reservoir surface Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet by dam for prior rights (first 152 second- feet of passing Azusa during flood season at rates Seasonally stored water in acre-feet Evapora- tion from reservoir surface Waste over spillway in acre-feet Year and itomth in acre-feet natural flow) in less than 1,900 in acre-feet acre-feet second- feet in acre-feet 1900 1,968 Jan. U 1,111 Feb. 1,230 Mar. 1,012 April 2,2V5 May 893 June 369 July 246 Aug. 238 Sept. 30 < Oct. 1,058 Nov. 10,010 1,269 Dec. Total or average 11,976 1901 10,010 6,861 Jan. 13,740 8,350 Feb. 44,099 9,138 Mar. 7.763 187 48,550 6,545 7,7'i3 187 April 8,023 228 40,600 6,990 8,023 228 May '• 7,878 242 32,799 3,/49 7,878 242 June ; 8,140 244 24,679 ],845 8,140 244 July 8,140 .184 16,295 1,240 8,140 184 Aug. 7,878 93 7,971 1,012 7,878 93 Sept. ' 1,4(6 Oct. 1,904 Nov. 1,660 Dec. Total or average 4i,822 1,178 50,570 47,822 1,178 1902 1,722 Jan. 2,055 Feb. 5,590 Mar. (2 8 498 3,928 72 8 April 73 11 418 2,398 73 11 May 72 12 334 1,190 72 12 .June 74 12 250 676 74 12 July 74 12 164 430 74 12 Aug. 72 6 78 298 72 6 Sept. 430 Oct. 1,131 Nov. ' 1,968 Dec. Total or average 437 61 21,816 437 61 (• 364 WATER RESOURCES OF CALIEORXIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1.900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve oi first 131.000 acre-feet of caperlty 180,000 acre- Flood Flood control control Run-off Paesed water Passed water Year and month at .Azusa Stage of re.^ervoir at by dam for prior rights pissing Azusa during Season-illy Evapora- tion r-,^rn Waste Stage of reservoir by dam for prior rights parsing .Azusa during acre-foet beginning of (first 152 second- fljod season storefl water in irom reservoir surface in acre-feet over spillway at beginning (first 1.52 second- fljod season mouth in acre-feet feet of natural flow) in at rates less than 1.900 acre-feet in acre-feet of month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet second- feet in acre-feet acre-feet second- feet in acre-feet 1903 Jan. 9,100 2,536 4,856 2 536 Feb. 5,665 1,708 5.497 1,189 6.554 5.497 Mar. 15,802 687 7,898 6,732 7,898 April 47.127 8,591 9,042 1.344 67 14,636 9,042 May- 13,343 45,265 9,116 8,963 244 50.322 9.116 June 5,653 40,285 5,653 9,703 272 44,322 5,653 (1 July 2,644 30,310 2,644 10,026 270 33.358 2.644 Aug. 1.783 20,014 1,783 10,026 202 22.039 1.783 Sept. 1,488 9,786 1.488 9,685 101 10,789 1.488 Oct. 1,476 1,476 1.476 Nov 1,428 1,428 1.428 Dec. Total or 1,476 1,476 1,476 average 106,985 50,037 6,045 49.747 1,153 50,037 1904 Jan. 1,500 1.500 1,500 Feb. 2,744 2,177 2. '77 Mar. 6,813 567 4,724 557 4 724 U April 5,337 ?,653 5,337 407 19 2,658 5,337 May 4,08!' 2,220 4.089 420 37 2,220 4,089 June 1,517 1,763 1,517 407 36 1,763 1,517 (1 July 861 1,329 861 420 3G 1.320 861 U Aug. 793 864 793 420 21 884 793 U Sept. 643 420 643 408 12 420 6t3 Oct. 7.38 738 C 738 Nov. 762 762 U 762 Dec. Total or l.a39 1,039 1,039 average 26,836 24.180 2.482 174 21,180 190S Jan. 2.251 2,251 2,251 Feb. 25,880 8,206 11.798 8 206 Mar. 75,140 5.876 0.281 18.198 17.674 9,281 .^pril May 19.580 53.537 9.042 8,727 197 8 1,533 9,042 17,090 55,151 9.344 10,942 271 (1 80,378 9,344 June 8,271 51.681 7,960 12.475 313 71,790 7,960 July 5,103 39,201 5.103 12,y8a 313 51,358 5,103 Aug. 2,631 25,902 2,631 12,989 232 35,935 2.631 Sept. 1.869 12.681 1.869 12,560 121 17,612 1,8'J9 Oct. 1,770 1.770 1,770 Nov. 2,660 2,660 2 660 Dec. Total or 2.470 2.470 2,470 average 164,715 62,587 29.996 70,882 1,450 ■ 62.587 THE CONTROL OF FliOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 365 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 2'10,000 acre-feet capacity Flood control Passed water t-oiEoually Evapora- tion from Waste Stage of reservoir by dam for prior rignts passing Azusa during Seasomlly Evapora- tion Waste Year and month stored o^er spillway in acre-feet at beginning of month in acre-feet (first 152 flood stored from over spillway in witcr in acre-feet reservoir surface second- feet of season at rates water in acre-feet reservoir surface in acre-feet nitural flnw) in less than 1,900 in acre-feet acre-feet acre-fee t second- feet in acre-feet 1903 2,536 Jan. 6 564 5,497 Feb. 6,732 7,898 Mar. 2.304 95 14,636 9.042 2..304 95 April 9,969 258 50,322 9,116 9,969 258 May 10,676 288 44,322 5,653 10,676 288 June 11,030 289 33,358 2,644 11,030 289 Jaly 11,030 220 22,039 1,783 11,030 220 .\ug. 10,676 113 10,789 1,488 10.676 113 Sept. 1.476 Oct. 1.428 Nov. 1,476 Dec. Total or average 55,685 1,263 50,037 55,685 1,263 1904 1.500 Jan. 2,177 Feb. 567 4,724 Mar. 407 29 2,656 5,337 407 29 April 420 37 2,220 4,089 420 37 May 407 3G 1,763 1,517 407 36 June 420 36 1,320 861 420 36 July 420 24 864 793 420 24 Aug. 408 12 420 643 408 12 Sept. 738 Oct. 762 Nov. 1,039 Dec. Total or average 2,482 174 24,180 2,482 174 1905 2,251 Jan. 8.206 Feb. 17,674 9,281 Mar. K!,429 264 83,533 9,042 13.429 264 Apri! 15,987 347 80,378 9.344 15,987 347 May 17,357 386 71,790 7,960 17.357 386 June 18,039 384 54,358 5,103 18,039 384 July 18,039 284 35,935 2,631 18,039 284 Aug. 17,459 153 17.612 1,869 17,459 153 Sept. 1,770 Oct. 2,660 Nov. 2,470 Dec. Total or average 100.310 1.818 (1 62.587 100,310 1,818 366 WATEU RESOURCES OF CALIFORNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood con trol reserve or first IR 131,000 acre-feet of capacity 1 Ou,uuu aiff c- Flood Flood control control Run-off at Azusa Passed water Passed water Year and month Stage of reservoir by dam for prior rights papsing Azusa during Seasonally Evapora- tion from reservoir surface Waste Stage of reservoir by dam for prior rights passing Azusa during in acre-fcct at beginning ^first 152 second- flood season stored water in over spillway at beginning of (first 152 second- flood season of feet of at rates acre feet in acre-fcct month in acre-feet feet of at rates month in acre-feet natural flow) in less than 1,900 in acre-feet natural flow) in less than 1,900 acre-feet second- feet in acre-feet acre feet second- feet in acre-feet 1906 Jan. 4,240 3,633 3,633 Feb. .3,%0 007 3,960 607 3,960 Mar. 129.000 607 7,561 24,303 607 7,561 2,864 April 34,600 97,743 9,042 19,634 11.660 274 119,182 9,042 May 21,000 91,7.33 9,344 18,263 375 12.5.198 9,344 June 1.5,500 84.751 9,042 20,518 426 111,414 0,042 July 9,3.50 70,265 8,664 22,606 452 90.348 8,664 Aug. 4,490 47,893 4.490 24,086 329 60,436 4.490 Sept. 2,840 23,478 2.840 23,305 173 29,637 2,840 Oct. 2,450 2,450 2,4.50 Nov. 2,400 2,400 2,400 Dec. Total or average 11,600 4,030 4,030 241,430 67,456 43,937 120,4.38 2,029 67,456 2.864 1907 Jan. 58,400 7,570 9,217 50,881 7,570 9,217 1,881 Feb. 47,100 5,872 8,439 31,125 54,872 8.439 31.125 Mar. 116,000 13,408 9,344 47,166 62,408 9,344 47,166 April May 58,400 72,898 9,042 11,708 238 121,898 9,042 21, .500 110,310 9,344 21.989 426 151,269 9,344 June 15,100 100,051 9,042 24,242 478 1,32,686 9,042 July 8,360 81,389 7,920 27,072 493 105,969 7,920 Aug. 5,390 54.264 5,390 27,300 359 70,528 5,390 Sept. 3,580 26,605 3,580 26,421 184 34,589 3,580 Oct. 4,090 4,090 4,090 Nov. 3,800 3,800 3.800 Dec. Total or average 3.600 3,600 3,600 345,320 82,808 129,172 138.732 2,178 82,808 80,172 1808 Jan. 11,100 4,973 4.617 4,973 Feb. 15,000 1.510 8.741 5,141 6,127 8,741 Mar. 12,700 2.628 9,255 12,386 9,2.55 April May 9,280 6,073 8,656 952 52 15,831 8,656 7,190 5,693 7,139 1,106 69 13.860 7,139 (1 June 4,190 4,569 4,190 1,071 61 11,067 4,190 July 2,560 3,437 2,560 1,106 57 8.309 2,560 Aug. 2,210 2,274 2,210 1,106 36 5,405 2,210 Sept. 1,820 1,132 1.820 1,120 12 (1 2,665 1,820 Oct. 2.070 2,070 2.070 Nov. 1.960 1,960 1,960 Dec. Total or average 2.870 2.870 2,870 72.950 56,444 0,758 6,461 287 56,444 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 367 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre ■feet capacity Flood control Passed water Seasonally stored water in acre-feet Evapora- tion from reservoir surface Waste over spillway in Stage of reservoir at beginning of by dam for prior righto (first 152 seconH- fect of passing Azusa during flood season at rates Seasonally stored water in acre-feet Evapora- tion from reservoir surface Waste over spillway in Year and month in acre-feet acre-feet month in acre-feet natural flow) in acre-feet less than 1,900 second- feet in acre-feet in acre-feet acre-feet 190S 3,633 .Jan. 607 3,960 Feb. 607 7,561 Mar. 19,209 333 122,046 9,042 19,673 339 April 24,974 466 127,.592 9,344 25,454 472 May 27,008 516 113,322 9,042 27,481 492 June 30,069 529 91,807 8,664 30,557 535 July 30,416 383 61,401 4,490 30,906 385 Aug. 29,437 200 30,110 2,840 29,910 200 Sept. 2,4.50 Oct. 2,400 Nov. 4,030 Dec. Total or a\erage 161,113 2,427 67,456 163,981 2,423 1907 7,570 9,217 .Jan. 56,753 8,439 Feb. 95,414 9,344 20,172 Mar. 19,650 337 181,898 9,012 29,388 446 April 30,209 530 201,422 9,344 40,265 650 May 32,194 .581 172,663 9,042 41,941 700 June 35,292 589 136,080 7,920 45,367 698 July 35,517 422 90,455 5,390 45,589 496 Aug. 34,371 218 44,370 3,580 44,122 248 Sept. 4,090 Oct. 3,800 Nov. 3,600 Dec. Total or average 187,233 2,677 82,808 20,172 246,672 3,238 190S 4,9/3 Jan. 6,127 8,741 Feb. 12,386 9,2.55 Mar. 2,496 09 15,831 8,656 2,496 99 April 2,721 123 13,860 7,139 2,721 123 May 2,623 135 11,007 4,190 2,623 135 June 2,711 133 8,309 2,560 2,711 1.33 July 2,711 89 5,465 2,210 2,711 89 Aug. 2,625 40 2,665 1,820 2,625 40 Sept. (1 2,070 Oct. 1,960 Nov. 2,870 Dec. Total or average 15.887 619 56,444 1.5,887 619 ( ;{68 WATEIt KESOUHCES OK CALIFOKNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum finod cor trol reserve or first 131,000 acre-feet of capacity ISu.uuu acre- Flood Flood control control Year and month Run-off at Azusa Stage of rsservnir Pasped by dam for prior rights water passing Azusa during Seasonally Evapora- tion Waste Stage of reservoir Passed by dam for prior rights water pissing Azusa during in acre-fee t at beginninK of month in acre-feet (first 152 flood stored trom over at (first 152 flood second- feet of season at rates water in acre-feet Ti^servoir surface spillway in acre-feet beginning of month in acre-feet second- feet of season at rates natural flow) in less than 1,900 in acre-feet natural flow) in less than 1.900 acre-feet second- feet in acre-feet second- feet in acre-feet acre-feet 1909 Jan. 2,5,500 5,.596 19,385 5.596 Feb. .50,400 519 8,440 42,858 19,904 8,440 13.213 Mar. 2t).300 8,621 9,,344 57,621 9,344 April 28,000 25,577 9,042 4,063 131 74,577 9,012 May 15,200 40,341 9,344 7,980 228 81,312 9,344 June 8,570 37.989 8,319 9,144 260 70.645 8,319 July 5,010 28,83ti 5.040 9,528 264 53.434 5,040 Aug. 3,120 19,044 3,120 9,528 196 35,323 3,120 Sept. 2..?20 9,320 2,320 9,225 r5 17,314 2,320 Oct. 2.310 2,310 2,310 Nov. 2,880 2,880 fl 2,880 Dec. Total or 20,903 199,510 6,346 6,346 averaRc 72,101 62,243 49.468 1,174 72,101 13,243 1910 Jan. 09,500 14,554 9,344 73„583 14,5.54 9,344 24.583 Feb. 11,500 1,127 8,435 2,()89 50,127 8,435 2,689 Mar. 9,590 I, .503 9,029 50,503 9,029 April 8,270 2,064 8,120 321 22 61.064 8,120 May 5,050 1,871 5,050 363 29 42,847 5,050 June 3 560 1,479 3,560 352 14 34,134 3.560 July 2,450 1,113 2,450 363 16 25,684 2.450 Aug. 1,710 734 1.710 363 16 16,957 1,710 Sept. 1,370 355 1,370 355 8,294 1.370 Oet. 1,560 1,560 1,560 Nov. 1.870 1,870 1,870 Dee. Total or 2.020 2,020 2,020 averaRe 118.4.50 54,518 76,272 2,117 97 54,518 27.272 1911 Jan. 37,200 fl 6,441 7,031 6,441 Feb. 44,300 23,728 S,440 53,874 30.759 8,140 11.905 Mar. 122.000 5,714 9,344 57,431 5J.714 9,344 57,434 .Aj.ril Nlay 28,230 60,936 9,012 9.774 212 109,036 9,042 16,600 70,108 9.344 13.936 317 111,071 9,344 (I June 7.500 63,111 7,322 15.247 357 95,757 7,322 (1 July 5,230 47,li85 5,230 15,816 355 72,274 5.230 Aug. 3.610 31,514 3,610 15.816 2!0 47,786 3,610 Sept. 2.830 15,4.38 2,830 15,303 i:;5 23,427 2,830 Oct. 3 140 3,140 3,14U Nov. 2.800 2,800 2,800 1) Dec. 2.870 2 870 2,870 Total or 270,280 70,413 average 118.330 8.'>.802 1.0>36 70.413 69,339 THE CONTROL OP FLOODS BY KE8ERV0IKS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 369 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity ■ 240,000 acre-feet capacity Flood control Passed water Evapora- Stage of by dam for prior pissing Azusa Evapora- Waste Year and Se.iaoiially tion from Waste r3s?rvoir rishts during Seisonally tion month stored over at (first 152 flood stored from over spillw.iy in acre-feet Witer in acre-fee t reservoir surface in acre-feet spillw.iy in acre-feet bRi^inning of month in acre-feet second- feet of natural fliw) in season at rates less than 1,900 water in acre-feet reservoir surface in acre-feet acre-feet second- feet in acre-feet 1903 5.596 ,Ia... 19,904 8,440 Feb. 70,864 9,344 Mar. 11,979 244 87,820 9.012 14,127 272 Anrii 16,174 349 92,379 9,344 18,392 381 May 17,079 383 79,462 8,319 19,225 414 .June 17,731 .380 60,074 5,040 19,949 410 July 17.7-31 278 .39,715 3.120 19,949 295 Aug. 17,165 149 19,471 2,320 19,314 157 Sept. 2,310 Oct. 2,880 Nov. 6,346 Dee. Total or 97,859 1,783 72,101 110,956 1,929 average 1910 14., 551 9.344 .Jan. 74,710 8,435 Feb. 77,775 9,029 Mar. 8.174 193 78,336 8,120 12,.588 2.50 April 8,475 2.38 65,648 5,050 13,036 306 May 8,202 248 52,306 3,560 12,616 317 June 8,475 252 .39,373 2,450 13,036 317 .lulv 8,475 188 26,020 1,710 13,036 238 Aug 8,199 95 12,746 1,370 12,625 121 Sept. 1,560 Oct. 1,870 Nov. 2,020 Dec. Total or 50,000 1,214 51,518 76,937 1,519 average 1911 6,441 .Ian. 30,759 8,440 Feb. 6K.619 9,344 10,977 Mar. 17,708 315 168.2!)8 9.042 27,179 423 April 22,142 428 159,854 9.344 31,928 ,551 May 23.1P5 466 134.631 7,322 32,670 585 .June 24,026 462 101. ,5,54 5.230 33,815 573 .July 24,026 .333 67,166 3.610 33.815 408 Aug. 23.2.50 177 32.943 2.830 32,733 210 Sept. 3,140 Oct. 2,800 Nov. 2.870 J)ec. Total or 134,.347 2,181 70.113 10.977 192.110 2,759 average ,'570 "VVATEH RESOURCES OF CALIFORNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 180,000 acre- 131,000 acre-feet of capacity Flood Flood control control Run-off at Azusa Passed water Passed water Year and mopth Stage nf reservoir at beginning by dam for prior rights passing Azusa during Seasonally Evapora- tion from reservoir surface in acre-feet Waste Stage of reservoir by dam for prior rights passing Azusa during in acre-feet (first 152 second- flood season stored water in over spillway at beginning ffirst 152 second- flood season ot month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet in acre-feet of month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet second- feet in acre-feet acre-feet second- feet in acre-feet 1912 Jan. 2,710 2,710 2.710 Feb. 2,230 2,230 2.230 Mar. 22,900 8,199 8.199 April 18,000 14,701 8.515 2.314 95 14.V01 8,515 May 10,900 21,777 8.828 4,273 163 21,777 8,828 June 4,990 19,413 4,990 4,634 182 19,413 4,990 July 3,060 14,597 3,060 4,790 184 14.597 3,060 Aug. 1,960 9,623 1,960 4,790 135 9,623 1.960 Sept. 1,550 4,698 1,550 4,634 64 4,698 1,.550 Oct. 1,830 1,830 1,830 Nov. 1,730 1,730 1.730 Dec. 1.760 1.760 1.760 Total or average 73,620 47.362 25,435 823 47.362 1913 Jan. 2,910 2,910 2.910 Feb. 13,200 4.753 4,753 Mar. 10,200 8,447 8.759 8.447 8.759 April May 7.140 9,888 7,091 1„547 75 9.888 7,091 4,970 8.315 4,970 1,608 93 8.315 4,970 June 2,890 6,614 2.890 1.557 95 6.614 2,890 July 1.690 4.962 1.690 1,607 93 4,962 1.690 Aug. 1.070 3.262 1,070 1,607 68 3,202 1,070 Sept. 893 1.587 893 1,555 32 1,587 893 Oct. 910 910 910 Nov. 2.280 2,280 2,280 Dec. Total or 2.170 2,170 2.170 average 50.323 40,386 9.481 456 40.386 1914 Jan. 61.400 6,271 41,989 6,271 1.248 Feb. 121,000 13,140 8,440 .59.505 53.881 8,440 51.246 Mar. 48,000 66,195 9,344 53,083 115.195 9.344 53,083 April May 21,400 51,768 9,042 8.291 193 100,768 9,042 1) 16,900 55.642 ".'.344 11,077 274 96.603 9,344 June 9,580 51.847 8,585 12.509 313 81,529 8,585 () July 5,570 40.020 5,570 13,258 317 64,634 5,570 Aug. 3,630 26,445 3,630 13.258 238 42,731 3.630 Sept. 2.730 12.949 2,730 12.826 123 20.945 2.V30 Oct. 2.770 2.770 2,770 Nov. 2.440 2,440 2,440 Dec. Total or 4,290 4,290 4,290 average 299,710 72,456 154,577 71.219 1.458 72,456 105.577 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 371 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre -feet capacity Flood cortrol Passed water Seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste ove r spillway in acre-feet Stage of reservoir at beginning of month in acre-feet by dam for prior rights (*irst 152 second- feet of natural flow) in acre-feet passing -Azusa during flood season at ratee less than 1,900 second- feet in acre-feet Seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1912 2,710 Jan. 2,2.30 Feb. 8,199 Mar. 2,.314 95 14,701 8,515 2.314 95 April 4,273 163 21,777 8.828 4,273 163 May 4,634 182 19,413 4,990 4,634 182 June 4,790 184 14,597 3,060 4,790 184 July 4,790 1.35 9,623 1,960 4.790 135 Aug. 4,634 64 4,698 1,550 4,634 64 Sept. 1,830 Oct. 1,730 Nov. 1,760 Dec. Total or average 25,435 823 47,362 25,435 823 1913 2,910 Jan. 4,753 Feb. 8,447 8,759 Mar. 1,.547 75 9,888 7,091 1,547 75 .April 1,608 93 8,315 4,970 1,608 93 May 1,557 95 6,614 2,890 1,557 95 June 1,607 93 4,962 1,690 1,607 93 July 1,607 68 3,262 1,070 1,607 68 Aug. 1,555 32 1,587 893 1,555 32 Sept. 910 Oct. 2,280 Nov. 2,170 Dec. Total or average 9,481 456 40,386 9,481 456 1914 6,271 Jan. .55,129 8,440 18,017 Feb. 149,672 9,.344 30,254 Mar. 16,225 298 158,074 9,042 2.5,519 405 April 19,239 391 144,508 9,344 28,847 514 May 20,460 430 122,703 8,585 29,763 .549 June 21,473 430 93,386 5,570 31,083 543 July 21,473 313 61,700 3,6.30 31,083 389 -Aug. 20,780 165 {) 30,288 2,730 30,088 200 Sept. 2,770 Oct. 2,440 Nov. 4,290 Dec. Total or average 119,650 2,027 72,456 4S.27I 176,383 2,600 .'{72 WATER R?:SOUKCES OF CALIFORNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Compute (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood con trol reserve or first ia 131,000 acre-feet of capacity lOVfUW tttlC- Flood Flood control control Run-off at .\zusa Passed water Passed water Year and month Stage of rcser\oir by dam for prior rights pissing .\zusa d.iring Seasonally Evapora- tion Waste Stage of reservoir by dam for prior rischts passing .\zusa during in at beginning (&Tst 152 flood stored trom over at (first 1.52 flood acre-feet second- season water in reservoir surface in acre-feet spillway beginning second- season 01 month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet in acre-feet of month in acre-feet feet of natural flaw) in at rates loss than 1.900 acre-feet second- feet in acre-feet acre-feet second- feet in acre-fee t 1915 .Ian. 7,380 4,428 2,632 4,428 Feb. 30,200 320 8,412 13,196 2,952 8,412 Mar. 2 1, .'500 8,912 9,344 24.740 9,344 April 17,300 21,068 9,042 3,.339 117 36.896 9,042 May 20,400 25.870 9,344 4.2.56 177 39,109 9,.344 Jump 11,400 32,403 8,967 7.807 238 42.213 8,967 .bily 7,010 26,881 7,010 8,875 254 34,2J1 7.010 Aug. 3,980 r<,752 3,980 8,875 190 22,595 3,980 Sept. 3,270 8,687 3,270 8,502 95 11,062 3,270 Oct. 2,770 2,770 2.770 Nov. 3,010 3,010 3,010 (1 Dec. 3,580 3,580 3,580 Total or average 131,800 7.3,157 15,828 41,744 1,071 73,1.57 1916 .)ati. 148,000 8,759 52,702 8,753 49,196 Feb. 3!),400 86,539 8,741 99,427 90,045 8,741 54,.508 Mar. 34,800 17,771 9,344 18 66,196 9,344 April 10,!)00 43,209 9,0'.2 6,913 174 91,6,52 9.042 May 10,400 46,980 9,130 9,304 248 87,483 9.130 .Func 5,830 38,098 5,830 9,314 264 70,993 5,830 July 4,770 29,120 4,770 9.624 264 53.444 4,770 Aug. 3,570 19,232 3,570 9,621 198 35,328 3,570 Sept. 2,810 9,410 2,810 9,314 96 17,314 2,810 Oct. (,0!0 6,473 6,473 Nov. 4,130 537 4,130 7 537 4.130 Dec. 13,600 .530 5,253 530 5,253 Total or average 294,220 77,852 152,147 54.093 1,251 77,852 103.701 1917 Jan. 9.280 8.877 8,172 9,467 8,877 8,172 Feb. 13.200 518 7,.551 9.985 7.,551 Mar. 13,600 6,167 9„344 15,634 i',344 April May tC.'iOO 10,423 9,042 I,G40 73 19,890 9.042 8,610 10.168 8„531 1,979 99 18,086 8,531 June 5,270 8,169 5,270 1,935 105 14,482 5,270 July 3,140 6,129 3,140 1,999 99 (1 10,882 3,140 Aug. 2,200 4,031 2,200 1,999 67 7,169 2,200 Sept. 1,510 1,965 1,510 1,935 30 3,497 1,510 Oct. 1.560 1,560 1,560 Nov. 1.840 1,840 1,840 (I Dec. Tutnl or 2,000 2,000 o| 2,000 average 72.710 1 60.160 9.467| 11.487 473 60,160 (} THE fONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 373 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre- feet capacity Flood control Passed water Seasonally Evapora- tion Waste Stage of reservoir at beginning of month in acre-feet by dam for prior rights passing Arusa during Seasonally Evapora- tion Waste Year and month stored WMterin acre-feet from reservoir surface in acre-feet over spillway in acre-feet (first 152 second- feet of natural flow) in flood season at rates less than 1,900 stored water in acre-feet from reservoir surface in acre-feet over spillway in acre-feet acre-feet second- feet in >> acre-feet 1915 4,428 Jan. 2,952 8,412 Feb. 24,740 9,344 Mar. 5,88» 101 36,896 9,042 5,884 161 April 7,728 224 39,109 9,344 7,728 224 May 10,165 280 42,213 8,967 10,165 280 June 11,313 293 34,201 7,010 11,313 293 July 11,313 220 22,595 3,980 11,313 220 Aug. 10,947 115 11,062 3,2; 10,947 115 Sept. 2,770 f)et. 3,010 Nov. 3,580 Dec. Total or average 57,300 1,293 73,157 57,350 1,293 1916 8,759 Jan. 139,241 8,741 43,704 Feb. 126,196 9,344 Mar. 14,747 280 151,652 9,042 24,473 393 April 17,393 307 137,644 9,130 27,472 496 May 17,165 384 110,946 5,830 26,895 513 June 17,736 380 83,538 4,770 27,793 498 July 17,736 278 5.5,247 3,570 27,793 363 Aug. 17,168 146 27,091 2,810 . 26,904 187 Sept. 6.473 1) Oct. 7 ,537 4,130 7 Nov. 530 5,253 Dec. Total or average 101,945 1,842 77,852 43,704 161,330 2,457 1917 8,877 8,172 Jan. 9,985 7,551 Feb. 15,634 9,344 Mar. 3,149 113 19,890 9,042 3,149 113 April 3,536 147 18,086 8,5ol 3,536 147 May 3,446 154 14,482 .5,270 3,446 154 J>me 3,501 152 10,882 3,140 3,501 152 July 3,561 111 7,169 2,200 3,561 111 Aug. 3,445 52 3,497 1,510 3,445 52 Sept 1,560 Oct. 1,840 Nov. 2,000 Dec. Total or average 20,698 729 00,160 20,698 729 t 374 WATER RESOURCES OF CALIFORNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 131,000 acre-feet of capacity 180,000 acre- Flood Flood control control Passed water Passed water Year and month Run-off at Azusa Stage of reservoir by dam for prior rights passing Azusa during Seasonally Evapora- tion fiom reservoir surface in acre-feet Waste Stage of reservoir by dam for prior rights pissing .\zusa during in acre-feet ai beginning (first 152 second- flood season ? to red water in over spillway at beginning of month in acre-feet (first 152 second- flood season of month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet in acre-feet feet of natural flow) in at rates less than 1.900 acre-feet second- feet in acre-feet acre-feet second- feet in acre-feet 1918 Jan. 2,020 2,020 2.020 Feb. 9,330 3,817 3.847 Mar. 73,200 5,t83 9,249 11, .341 5,483 9.249 April IV, 000 58,093 9,012 9,314 206 69,434 9.042 May 10.000 56,531 8.993 11,216 276 66.012 8.993 June 6,010 46,016 6,010 11.097 292 53,603 6,010 July 3,970 34.657 3,970 11,467 293 40..347 3.970 Aug. 2,840 22,8ii7 2,840 11.467 218 26.663 2.840 Sept. 2,330 11.212 2.330 11,099 113 13,060 2.330 Oct. 2.930 2 930 2,930 Nov. 3,140 3,140 3,140 Dec. Total or average 4,370 4,370 C 4,370 137,110 58,741 11,341 65.660 1,398 58,741 1919 Jan. 3,300 3,300 3.300 Feb. ^110 4 110 4,110 Mar. 6,110 6,110 6,110 April May 6,010 6,010 6,010 3,810 3.810 3,810 June 1,890 1 ,890 1,890 July 1.320 1,320 1,320 Aug. 935 (1 935 935 Sept. 1,010 1,010 • c 1.010 Oct. 2.040 2,040 2,040 Nov. 2,130 2,130 2,130 Dec. Total or average 5.340 5,209 5,209 38,005 37,874 37,874 1920 Jan. 3,260 131 3,260 131 3,260 Feb. 12.700 131 5.854 131 5.851 Mar. 36,200 6.977 9.344 6.977 9.344 April May 25.100 33.833 9.042 5,389 153 33,833 9,0^2 12.600 44.349 9,344 8,776 240 44,.349 9.344 June 7.380 38. ,589 7,349 9,286 264 38.589 7,3-(9 July 4.670 29.070 4,670 9,603 270 29,070 4,670 Aug. 3,200 19,197 3.2C0 9,603 200 19.197 3.200 Sept. 2.030 9,394 2,0.30 9,292 102 9.394 2.030 Oct. 2,000 2,000 2,000 Nov. 2,380 2,380 2.380 Dec. Total or average 2,210 2.210 2,210 113.730 60.683 51. 949 1,229 60,683 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 375 feet passed for prior rights, onal storage each year. Maximum flood control reserve 131,000 acre-feet. feet capacity 240,000 acre-feet capacity Flood control Passed water Seasonally Evapora- tion from Waste Stage of res£n.-oir by dam for prior rights passing Azusa during Seasonally Evapora- tion Waste Year and month stored over spillway in aore-feet at (first 152 flood Stored trom over spillway in acre-feet water in acre-feet reser\-oir surface in acre-feet besinnin^ of ■ month in acre-feet second- feet of natural flow) in season at rates less than 1,900 water in acre-feet reservoir surface in acre-feet acre-feet second- feet in acre-feet 1918 2,020 Jan. 3,847 Feb. 5,483 9.249 Mar. 11,146 234 69.434 9,042 11,146 2.34 .^pril 13,110 306 66,012 8,993 13,110 306 May 12.933 323 53.603 6.010 12,933 323 June 13,363 321 40,347 3,970 13,363 321 July 13,363 240 C 26,663 2,840 13,363 240 Aug. 12,933 127 13,060 2,330 12,933 127 Sept. 2.930 Oct. 3,140 Nov. 4,370 Dec. Total or average 76,818 1,551 58.741 76,848 1,551 1919 3,300 Jan. 4,110 Feb. 6,110 Mar. 6,010 .\pril 3,810 May 1,890 June 1.320 July 935 .\ug. 1,010 Sept. 2,040 Oct. 2,130 Nov. 5,209 Dec. Total or average 37,874 1920 131 3,260 Jan. 131 5,854 Feb. 6,977 9.344 Mar. 5.389 153 33,833 9.042 5,.389 153 April 8.776 240 44,349 9..344 8,776 240 May 9,286 264 38,589 7,349 9,286 264 June 9,603 270 29,070 4.670 9.603 270 July 9,603 200 19,197 3,200 9,603 200 .\ug. 9,292 102 9,394 2,030 9,292 102 Sept. 2,000 Oct. 2,380 Nov. 2,210 Dec. Total or average 51,949 1,229 60,683 51,949 1,229 :}7<) WATER RESOURCES OF CALIFORNIA. TABLE 12a (Continued;. SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Compute (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flootJ ccn trol reserve or first 1B r\ nnn ««*»_ 131,000 acre-feet of capacity 1 OxifViju ai.1 c- Flood Flood control control Hun-aff at Passed water Passed water Year and Staec of by dam for prior passing Azusa Evapora- Waste Stage of by dam for prior passing Azusa month .^zu.sa reservoir rights during Seasonally tion reservoir rights during in at (first 152 flood stored from i)\ er spillway at (first 152 flood acre-fee t beginning second- season water in reservoir surface beginning second- season of !eet of at rates acre-feet m acre-feet 01 month in acre-feet feet of atiate? month in acre-fee' natural flow) in less than 1,900 in acre-feet natural flow) in less than 1,900 acre-feet second- feet in acre-feet acre-feet second- feet in acre-feet 1921 Jan. 5.100 4,405 4,405 Feb. 4,490 755 4,490 755 4,490 Mar. 15,400 755 7,288 755 7,288 April 6,070 8,867 6,070 1,386 67 8,837 6,070 May 15,700 7,414 6.835 1,432 85 7,414 6,835 Juno 8,980 14,762 7,(i2j 3,510 1.55 14,762 7,920 July 3,830 12,157 3,830 3,978 169 12,157 3,830 Aug. 2,450 8.010 2,450 3,978 121 8,010 2,450 Sept. 1,840 3,911 1,840 3,859 52 3,911 1,840 Oct. 2,040 2,040 2,040 Nov. 1,800 1,800 1,800 Dec. Total or average 119,000 5,045 38,907 5,045 6,295 186,760 54,013 38,907 18,143 649 54,013 6,295 1922 Jan. 62,100 75.048 9,344 108.425 107,660 9,344 100,784 I'Vl). 88,900 19,379 8,440 83,060 59,632 8,440 74,313 Mar. 47,800 16,779 9.344 3,196 65,779 9,344 3,353 Auril May 31,400 52,039 9,042 8,334 192 100.882 9,012 24,700 65,871 9,344 13,084 303 106,702 9,344 June 14,400 67,840 9,012 16,400 373 100,363 9,012 July 9,100 56,425 8,576 18,735 392 80,924 8,576 Auk. 5.080 37.822 5,080 18,997 287 54,037 5,080 Sept. 3,290 18,538 3,290 18,385 153 26,493 3,290 Oct. 3,110 3,110 3,110 Nov. 5,310 4,519 4,519 Dec. Total or average 21,500 791 8,466 791 8,456 316,690 87,587 194,681 93,935 1,700 87,587 178,4.50 1923 Jan. 7.130 13,835 6,968 13,042 13,835 6,968 Feb. 7,830 955 7,791 13,997 7 791 Mar. 7,320 994 7,320 14,036 7,320 April May 8,330 994 8,079 157 8 14,036 8,079 5,480 1.080 5,480 210 12 11,983 5,480 June 3,700 858 3,700 2W 12 9.537 3,700 July 2,420 t>42 2,420 212 8 7,159 2,420 Auk. 1,990 422 1.990 212 6 4,707 1,990 Sept. 1.750 204 1,7.50 204 2,293 1.750 Oct. 1.71(1 1,710 1,710 Nov. 1 ,960 (1 1.960 1,960 Der. Total or averiiKO 2,130 2.130 2,130 (1 61.760 51,298 13,042 1,199 46 61.298 (1 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 377 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre -feet capacity Flood control Passed water Seasonally stored Evapora- tion from Waste over Stage of reser\oir at by dam for prior rights (first 152 pissing Azusa during flood Seasonally stored Evai)ora- tion from Waste over spillway Year and month water in reservoir surface in acre-feet spillway beginning second- season water in reservoir surface in acre-feet acre-feet in acre-feet of month in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet in acre-feet acre-feet second- feet in acre-feet 1921 4,405 Jan. 755 4.490 Feb. 755 7,288 Mar. 1,386 67 8,867 6,070 1,386 67 April 1,432 85 7,414 6,835 1,432 85 May 3,510 155 14,762 7,920 3,510 155 June 3,978 169 12,157 3,830 3,978 169 July 3,978 121 8,010 2,450 3,978 121 Aug. 3,859 52 3,911 1,840 3,859 52 Sept. 2,040 Oct. 1,800 Nov. 5.045 Dec. Total or average 18,143 649 54 013 18,143 649 1922 113,955 9, ,344 52,703 Jan. 114,008 8,440 68,689 Feb. 125,779 9,344 3,196 Mar. lfi,241 297 161,039 9,042 25,999 411 April 21,277 418 156,987 9,344 31,353 515 May 24,317 480 140,445 9,042 34,086 603 June 26,917 494 111.114 8,576 37,012 611 July 27,185 359 74,015 5,080 37,280 434 Aug. 26,306 187 36,301 3,290 36,081 220 Sept. 3,110 Oct. 4,519 Nov. 791 8,456 Dec. 142,243 2,235 87,.587 124.588 201,811 2,824 1 \jliii \ii average 1923 13,835 6,968 .Ian. I 13,997 7.791 Feb. \ 14,036 7.320 Mar. 2,211 93 14,036 8,079 2,211 93 .April 2,331 115 11,983 5.480 2,331 115 May 2,257 121 9,.537 3,700 2,257 121 June 2.331 121 7,159 2.420 2,331 121 July 2, .331 83 4.707 1.990 2.331 83 Aug. 2,253 40 2.293 1.750 2,253 40 Sept. 1.710 Oct. n 1 ,960 Nov 2,130 " Doc. Total or 13,714 573 51,298 13,714 , 573 average 24—52411 378 WATER RESOURCES OF CALIFORNIA. TABLE 12a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL AND SEAS Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Run-off at Azusa in acre-feet Maximiim flood control reserve or first 131,000 acre-feet of capacity 180,000 acre- Year and month Stage of rejervoir at beginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1924 Jan. Feb. Mar. April Ma> June July Aug. Sept. Ocl. Nov. Dec. Total or average 1925 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or average 2,170 1,790 4,130 6,190 3,650 1,600 1,000 750 744 873 1,190 1,780 416 349 278 209 136 65 2,170 1,790 3,714 6,190 3,650 1,660 1,000 756 744 873 1,190 1,780 59 61 59 61 61 59 8 10 10 12 10 6 416 349 278 209 136 65 2,170 1,790 3,714 6,190 3,650 1,660 1,000 750 744 873 1 190 1,780 25,933 1,710 1 ,020 2,510 7,200 3,050 1,840 82-1 621 492 873 1,010 1,050 87 1,518 1,204 898 589 288 25,517 1,710 1,620 2.423 5,765 3,050 1,840 824 621 492 873 1,010 1,650 360 285 278 285 285 278 56 4 29 28 24 16 10 u 87 1.518 1,204 8',18 589 288 25,517 1,710 1,620 2,423 5,765 3,050 1,840 824 621 492 873 1.010 1,650 23,400 21.878 1,411 111 21,878 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." ONAL STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 12, page 158.) 379 feet passed for prior rights, onal storage each year. Maximum flood control reserve 131,000 acre-feet. feet capacity 2'10,000 acre-feet capacity Seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in acre-feet Flood control water passing Aznsa during flood season at rates less than 1,900 second- feet in acre-feet Seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year and • month 59 61 59 61 61 59 8 10 10 12 10 I 416 .349 278 209 136 65 2,170 1,790 3,714 6,190 3,650 1,660 1,000 756 744 873 1,190 1,780 59 61 59 61 61 59 8 10 10 12 10 6 1924 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or average 1925 Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Total or average 360 285 278 285 L 285 t 278 W 56 4 29 28 24 16 10 u in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in acre-feet water passing Anjsa during flood season at rates less than 1,900 second- feet in acre-feet 1900 Jan. 1,968 1,968 19.043 1.968 Feb. 1,111 1,111 17,691 1.111 Mar. 1.230 1,230 16,469 1,230 April 1,012 1,012 15,117 1.012 May 2,275 2,275 13.713 2.2". 5 June 893 893 12,240 893 July 369 369 10,796 369 Aug. 246 246 9.295 246 Sppt. 238 238 7.820 238 Oct. 307 307 6.426 307 Nov. 11,068 1,058 5,018 l.a58 Dec. 1.269 10.010 1,269 13,687 1,269 Total or average 21,986 11,976 11,976 1901 Jan. 10,391 10,010 6,661 12.810 12,335 6,661 Feb. 38,709 930 8,350 19.884 14,713 8.350 Mar. 13,589 11,405 9,138 43,850 9.138 April 6,545 15,856 6,545 2.499 99 46,949 6.545 May 7,440 13,258 6,990 2.582 117 45,459 6,990 June 3,749 11,009 3,749 2,618 129 44.317 3.749 July 1,845 8,262 1,845 2.704 12ii 42,722 1.845 Aug. 1,240 5,433 1.240 2.704 79 41.041 1.240 Sept. 1.012 2,650 1,012 2.610 40 39.389 1.012 Oct. 1,476 1,476 37.850 1,476 Nov. 1,904 1,904 36.327 1.904 Dec. 1,660 1.660 34.909 1.660 Total or aveiagc 89,560 50.570 32.694 15.717 589 50.570 1902 Jan. 1,722 1.722 33,557 1.722 Feb. 2,055 2,055 32.205 2.055 Mar. 6,088 5.590 30.983 5.590 .\pril 3,028 498 3.928 72 8 30.129 3.928 May 2,398 418 2.398 73 11 28.679 2.398 June 1.190 334 1.190 72 12 27,143 1.190 July 676 250 676 74 12 25,620 676' Aug. 430 164 430 74 12 24,022 430 ! Sept. 298 78 298 72 6 22,448 298 Oct. 430 430 20.972 430 Nov. 1.131 1.131 19.497 1.131 Dec. Total or 1,968 1.968 18.111 1.968 average 22,314 1 - 21.816 437 61 »l 21.816 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN.'' OVER- YEAR STORAGE COORDINATED. tions Carried Out on a Daily Basis. mary, see Table 13, page IbO.) 385 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield Flood control Yield in a Passed water in a Season- uni- formly con- Evapora- tion Waste Stage of reservoir by dan. for prior rights (first 1.52 second- feet of natural flow) in acre-feet passing Azusa during fiiod season at rates less than 1,900 second- Season- uni- formly con- Evapora- tion Waste Year iind month ally stored water in acre-feet tinuous supply front, over- year storage from reservoir surface in acre-feet over spill- way in acre-feet at be- ginning of month in acre-feet ally stored waterin acre-feet tinuous supply from over- year storage from reservoir surface in acre-feet over spill- way in acre-feet in acre-feet feet in acre-feet in acre-feet 1900 1,352 52,419 1,968 2,520 Jan. 1,222 49,899 1.111 2,276 Feb. 1,352 47,623 1.230 2,520 Mar. 1,309 95 45,103 1,012 2,439 176 April 1,352 121 42,488 2,275 2.520 230 May 1,309 135 39,738 893 2.439 264 June 1,352 149 37,035 369 2,520 299 July 1,352 123 34,216 246 2,520 268 Aug. 1,309 85 31,428 238 2.439 200 Sept. 1,352 56 28,789 307 2,520 145 Oct. 1,309 32 26,124 1,058 2,439 95 Nov. 1,352 33.600 1,269 2.520 Dec. Total or 15,922 796 11,976 29.672 1.677 average 1901 1,352 31,080 6,661 2.520 Jan. 1,222 32,290 8,350 2,276 Feb. 1,352 60,373 9,138 2,520 Mar. 1,309 181 62,304 6,545 2,439 214 April 1,352 240 59,651 6,990 2,520 284 May 1,309 286 57,297 3,749 2,439 331 June 1,352 329 54,527 1,845 2,520 381 July 1,352 300 51,626 1,240 2,520 341 Aug. 1,309 230 48,765 1,012 2,439 256 Sept. 1,352 171 46,070 1,476 2,520 188 Oct. 1.309 109 43.362 1,904 2,439 121 Nov. 1,352 40.802 1,660 2,520 Dec. Tnfnl nr 15,922 1,846 50,570 29,672 2,116 1 ULdl Ul average 1902 1,352 38,282 1,722 2,520 Jan. 1,222 35,762 2,055 2,276 Feb. 1,352 33,486 5,.590 2,520 Mar. 1,309 141 31,464 3,928 2,439 143 April 1,352 184 28,882 2,398 2„520 182 May 1,309 214 26,180 1,190 2.439 208 June 1,352 246 23,533 676 2.520 232 July 1,352 222 20,781 430 2,520 202 Aug. 1,309 167 18,059 298 2.439 145 Sept. 1,352 123 15,475 430 2.520 99 Oct. 1,309 77 12,850 1,131 2,439 58 Nov. 1,352 10,359 1,968 2.520 Dec. Total or average 15,922 1.374 21,816 29.672 1,269 ^86 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 131,000 acre-feet of capacity 1 80,uuu acre- Flood Yield Flood control control Run-off at Azusa in acre-feet Passed water in a Passed water Year and month Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights (first 152 second- feet of natural flow) in passing Azusa during flood season at rates less than 1,900 Se.ison- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet ty dam for prior rights (first 152 second - feet of natural flow) in passing Azusa during flood season at rates less than 1.900 acre-feet second- acre-feet second- feet in acre-feet in acre-feet feet in acre-feet 1903 Jan. 9,100 2,536 4,8o6 16.759 2.536 Feb. 5,665 1,708 5.497 1,189 21.971 5,497 Mar. 15,802 687 7,898 20.917 7,898 April 47,127 8,591 9,042 1,344 67 27.469 9,042 May 13,343 45,265 9,110 8,963 244 64,065 9.116 (I June 5,653 40,285 5,653 9,703 272 66,633 5,653 July 2,644 30.310 2,644 10.026 270 63.947 2,644 Aug. 1,783 20,014 1,783 10,026 202 61,067 1,783 Sept. 1,488 9,786 1,488 9,685 101 58,291 1,488 Oct. 1,476 1,476 55,623 1.470 Nov. 1,428 1,428 54,057 1,428 Dec. 1,4/6 1,4,6 52.609 1,476 Total or average 106,980 50,037 6.045 49.74 ( 1.156 50,037 1904 Jan. 1,500 u 1,500 51.257 1,500 Feb. 2,744 2.177 49.905 2,177 Mar. 6,813 567 4,724 49.207 4,724 April 5,337 2,656 5,337 407 29 49.944 5,337 May 4,089 2,220 4.089 420 37 48,447 4,089 Juno 1,517 1,763 1,517 407 36 46,845 1,517 July 861 1,320 861 420 36 45.240 861 Aug. 793 804 793 420 24 43.545 793 Sept 643 420 643 (I 408 12 41,880 643 Oct. 738 738 40.333 738 (1 Nov. 762 762 38,802 762 Dec. Total or 1.039 1.039 37,378 1.039 average 26,836 24.180 2.482 174 24.180 1905 Jan. 2,251 2.251 36.026 2.251 Feb. 25,880 8.206 11.798 34,674 8,206 Mar. 75,140 5,876 9.281 18.198 51.126 9.281 13,658 April 19,580 53,537 9.042 8.727 197 101.975 9.042 May 17,090 55,151 9.344 10.942 274 104.952 9.344 June 8,271 51,681 7.960 12.475 313 102.698 7.960 July 5,103 39.204 5.103 U 12,989 313 91.355 5.103 Aug. 2.631 25.902 2.631 12,989 232 79.225 2.631 Sept. 1,869 12.681 1.689 12,560 121 67,175 1.869 Oct. 1.770 1.770 u 55.631 1.770 Nov. 2,660 U 2,660 54.065 2.660 Dec. Total or average 2,470 2,470 52,617 2,470 164.7I5J 62.687 29.906 70,682 " 1.450 62,587 13,658 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) 387 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. I feet capacity 240,000 icre-f eet capacity Yield Flood control Yield in a Passed water in a Season- uni- formly con- Evapora- tion Waste Stage of reservoir by dam for prior rights (first 152 second- feet of natural flow) in acre-feet passing Azusa during flood season at rates less than 1.900 second- Season- uni- formly con- Evapora- tion Waste Year and month ally stored water in acre-feet tinuous supply from over- year storage from reservoir surface in acre-feet over spill- way in acre-feet at be- ginning of month in acre-feet ally stored water in acre-feet tinuous supply from over- year storage from reservoir surface in acre-feet over spill- way in acre-feet m acre-feet feet in acre-feet in acre-feet 1903 1,352 /,839 2,536 2,520 Jan. 1,222 11,883 5,497 2,276 Feb. 1.352 9,775 7,898 2,520 Mar 1.309 180 15,159 9,042 2,439 171 April 1,352 307 50,634 9,116 2.520 268 May 1.012 1,309 365 52,073 5,653 2,439 311 June 1,107 1,352 421 49,323 2,644 2,520 359 July 1,045 1,352 379 46,444 1,783 2,520 321 Aug. 1.071 1.309 288 43,603 1,488 2,439 240 Sept. 1.352 214 40,924 1,476 2,520 176 Oct. 1,309 139 38,228 1,428 2,439 113 Nov. 1,352 35,676 1,476 2,520 Dec. Total nr 4,235 15,922 2.293 50,037 29,672 1,959 average 1904 1,352 33,156 1,500 . 2,520 Jan. 1,265 30,636 2,177 2,358 Feb. 1,352 28,845 4,724 2,520 Mar. 1,309 188 28,414 5,337 2,439 135 April 1,352 250 25,840 4,089 2,520 173 May 1,309 296 23,147 1,517 2,439 194 June 1,352 343 20,514 861 2,520 216 July 1,352 313 17,778 793 2,520 184 Aug. 1,309 238 15,074 643 2.439 129 Sept. 1,352 179 12.506 738 2,520 87 Oct. 1.309 115 9,899 762 2,439 50 Nov. 1,352 7.410 1,039 2,520 Dec. Total or average 15.965 1,922 21,180 29.754 1,168 1905 1.352 4,890 2.251 2,520 Jan. 1,222 2,370 8,206 2,276 Feb. 1.352 17,768 9,281 2.520 Mar. 5,949 1,309 303 81,107 9,042 2,439 268 April 8,237 1,352 411 88,938 9,344 2,520 377 May 9,875 1,309 470 93,787 7,960 2,439 464 June 10,266 1,352 512 91,195 5.103 2,520 527 July 10,266 1,352 432 88,148 2.631 2,520 482 Aug. 9.935 1,309 300 85,146 1,869 2,439 365 Sept. 1,352 214 82,342 1,770 2,520 272 Oct. 1,309 139 79,550 2,660 2,439 176 Nov. 1,352 76.935 2,470 2,520 Dec. Total or average 54,528 15,922 2.781 62.587 29,672 2,931 388 WATER RESOURCES OF CALIFORNIA. TABLE 13a f Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first IgQ t\nn ....PA- 131,000 acre-feet of capacity Flood Yield Flood control control Run-off at Azusa in acre-feet Passed water in a Passed water Year and month Stage of reservoir at be- ginning of month in acre-feet by dim for prior rights (first 152 second- feet of natural flow) in pissing Azusa during flood season at rates less than 1,900 Season- ally stored waterin acre-feet uni- formly con- tinuous supply from over- year storage Evapora- tion from reservoir surface in acre feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet by dim for prior rights (first 152 second- feet of natural flow) in passing Azusa during flood season at rates less than 1.900 acre-feet second- acre-feet second- feet in in acre-feet feet in acre-feet acre-feet 1906 Jan. 4,240 3,633 51.265 3.633 Feb. 3.960 607 3.960 50.520 3.960 Mar. 129,000 607 7,561 24,303 49,298 7.561 23.965 April 34,600 97.713 9,042 19,634 11,660 274 145,420 9.042 15.432 May 21,000 91.733 9,344 18,263 375 140.852 9.314 June 15.500 84,751 9,042 20,518 426 135.105 9.042 July 9,350 70,265 8.664 22,606 452 121,812 8.664 Aug. 4,490 47,893 4,490 24,086 329 100,040 4.490 Sept. 2,840 23,478 2,840 23,305 173 57,426 2.840 Oct. 2,450 2,450 55,759 2.450 Nov. 2,400 2,400 54,193 2.400 Dec. 11,600 4,030 52,745 4.030 Total or average 241,430 " 67,456 43,937 120,438 2.029 67,456 39.397 1907 Jan. 58,400 7,570 0,217 50,881 58,963 9,217 51.921 Feb. 47,100 5,872 8,439 31,125 54,873 8,439 29.904 Mar. 116,000 13,408 9,344 47,166 62.408 9,344 45.814 .\pril 58,400 72,898 9,042 11,708 238 121,898 9,042 May 21,500 110.310 9,344 21,989 426 160,351 9,344 June 15,100 100,051 9,042 24,242 478 151,129 9,042 July 8,360 81,389 7,920 27,072 493 133.496 7,920 Aug. 5,390 54.264 5,390 27,300 359 107,476 5,390 S3pt. 3,580 26.605 3,580 26,421 184 81,011 3.580 Oct. 4,090 4,090 55.644 4.090 Nov. 3.800 3,800 54.078 3.800 Dec. 3,600 3,600 52.630 3.600 Totel or average 345,320 82,808 129,172 138,732 2.178 82.808 127.639 1908 Jan. 11,100 4,973 4,617 51.278 4.973 5.543 Feb. 15,000 1.510 8,741 5,141 50.510 8.741 4,616 Mar. 12,700 2.628 9,255 58.888 9.255 April May 9.280 6.073 8,656 052 52 52,981 8.656 7.190 5.693 7,1.39 1,106 69 52,100 7.139 June 4.190 4.569 4,190 1.071 61 50,537 4.190 July 2.560 3.437 2,560 1.106 57 48.919 2.560 Aug. 2.210 2.274 2,210 1.106 36 47.208 2.210 Sspt. 1.820 1.132 1,820 1,120 12 45.531 1.820 Oct. 2.070 2.070 43.970 2,070 Nov. 1.960 1,960 42.432 1,960 Dec. 2.870 2,870 41.000 2.870 Total or average 72.950 1 56,444 9,758 6.461 287 56.444 10,159 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED. tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) 389 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield Flood control Yield in a Passed water in a Season- ally stored water in uni- formly con tinuous supply from E-. apora- tion from reservoir surface Waste over spill- wiy Stage of reservoir at be- ginning of by dam for prior rights f first 152 second- feet of natural flow) in acre-feet passing Azusa during flood season Season- ally stored waterin uni- formly con- tinuous supply from Evapora- tion from reservoir surface Waste over spill- way Year and month acre-feet over- year storage in acre-feet in acre-feet month in acre-feet at rates less than 1,900 second- acre-feet over- year storage in acre-feet in acre-feei in acre-feet feet in acre-feet in acre-feel 1906 1,352 74,415 3,633 2,520 Jan. 1,222 72,502 3,960 2,276 Feb. 1,352 70,226 7,561 9,428 2,520 Mar. 13,028 1,309 357 179,71V 9,042 6,365 2,439 444 April 1,5,553 1,352 498 196,027 9,344 11,680 2,520 636 May ir,843 1,309 569 192.847 9,042 14,159 2,439 755 June 20,527 1,352 609 181,952 8,664 16,782 2,520 857 July 20,774 1,352 488 162,479 4,490 17,151 2,520 734 Aug. 20,043 1,309 315 142,074 2,840 16,587 2,439 518 Sjpt. 1,352 214 122,530 2,450 2,520 357 Oct. 1,309 139 119,653 2,400 2,439 235 Nov. 1,352 116,979 4,030 2,520 Dec. Total or average 107,768 15,922 3,189 67,456 9,428 82,724 29,672 4,536 1907 1,352 122,029 9,217 53,819 2,520 Jan. 1,222 114,873 8,439 28,878 2,276 Feb. 1,352 122,380 9,344 44,618 2,520 Mar. 9,221 1,309 375 181,898 9,042 230 6,475 2,439 446 April 19,487 1,352 539 221,606 9,344 16,826 2,520 698 May 21,773 1,309 609 213,718 9,042 19,251 2,439 815 June 24,466 1,352 642 197,271 7,920 21,922 2,520 906 July 24,651 1,352 462 172,363 5,390 22,149 2,520 766 Aug. 23,737 1,309 321 146,928 3,580 21,428 2,439 531 Sept. 1,352 214 122,530 4,090 2,520 357 Oct. 1,309 139 119,653 3,800 2,439 236 Nov. 1,352 116,978 3,600 2,520 Dec. Total or average 123,335 15,922 3,301 82,808 127,605 108,051 29,672 4,755 1908 1,352 114,4.58 4,973 7,555 2,520 Jan. 1,265 110,510 8,741 4,224 2,358 Feb. 1,352 110,187 9,255 2,520 Mar. 1,309 196 111,112 8,656 2,439 317 April 1,352 262 108.980 7,139 2,520 420 May 1,309 309 106,091 4,190 2,439 494 June 1,352 359 103,158 2,560 2,520 573 July 1,352 325 100,065 2,210 2,520 524 Aug. 1,309 252 97,021 1,820 2,439 397 Sept. 1,352 183 94,!85 2,070 2,520 297 Oct. 1,309 123 91,368 1,960 2,439 194 Nov. 1,352 88,735 2,870 2,520 Dec. Tola' or average 15,965 2,012 56.444 11,779 29,754 3,216 390 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Max Imum flood control reserve or first iQn 131,000 acre-feet of capacity 1 oU,uuu abi o- Flood Yield Flood control control Run-off at Azusa in acre-feet Passed water in a Passed water Year and rr.onth Stage of reservoir at be- ginning of by dam for prior riahts (first 152 pecond- feet of passing Azusa during flood season at rates Season- ally stored watcrin acre-feet uni- formly con- tinuous pupply from Evapora- tion from reservoir surface Waste over spill- way in Stage of reservoir at be- ginnii'g of month in acre-feet by dam for prior rights (first 152 second- feet of passing Azusa during flood season at rates month in acre-feet natural flow) in less than 1,900 over- year storage in acre-feet acre-feet natural flow) in less than 1,900 acre-feet second- acre-feet second- feet in in acre-feet feet in acre-feet acre-feet 1909 Jan. 25,500 5,596 19,385 39,648 5.596 8,681 Feb. 5!),400 519 8,440 42,858 49.519 8.440 41,897 Mar. 26,300 8,621 9,344 57,360 9.344 April 28,000 25,577 9,042 4,003 131 72,964 9.042 May 15.200 40,341 9,344 7,980 228 89.165 9,344 June 8,570 37,989 8,319 9,144 260 88,259 8,319 July 5,040 28,830 5,040 9,528 264 80,467 5,040 Aug. 3,120 19,044 3,120 9,528 196 71,998 3,120 Sept. 2,320 9,320 2,320 9.225 95 63,656 2,320 Oct. 2.310 2,310 55.087 2,310 Nov. 2,880 2,880 54.121 2,880 Dec. Total or average 20,900 0,346 62,673 6,346 1,682 199,540 72,101 62,243 49,408 1,174 72,101 52,260 1910 Jan. 09,500 14,554 9,344 73,583 64,193 9.344 72.870 Feb. 11,500 1,127 8,435 2,089 50,127 8,435 2.292 Mar. 9.590 1,503 9,029 49,678 9.029 April 8,270 2,064 8.120 321 22 48,887 8,120 May 5.050 1,871 5,050 363 29 47,542 5.050 June 3,500 1,479 3,500 352 14 45,940 3,560 July 2,450 1,113 2,450 363 16 44.340 2,450 Aug. 1,710 734 1,710 363 16 42.051 1,710 Sept. 1,370 355 1,370 355 40.992 1,370 Oct. 1,500 1.560 39,449 1,560 Nov. 1,870 1,870 37.923 1,870 Dec. Total or average 2,020 2.020 36.501 2,020 118,450 54,518 76,272 2,117 97 54.518 75,162 1911 Jan. 37,200 6,441 7,031 35,149 6.441 6.949 Feb. 44,300 23,728 8,440 53,874 57,007 8,440 38.010 Mar. 122,000 5,714 9,.341 57,434 54.235 9,344 55,867 April 28,200 60,930 9,012 9,774 212 109,082 9,012 May 10,000 70,108 9,344 13,936 317 120,008 9.344 June 7,500 63.111 7,322 15,247 357 114.155 7,322 July 5,230 47,685 5,230 15,816 355 99.851 5,230 Aug. 3,010 31.514 3,010 15,816 260 84.807 3,610 Sept. 2,830 16.438 2,830 15.303 135 69.915 2,830 Oct. 3,140 3.140 55.688 3,140 Nov. 2,800 2,800 64.121 2,800 Dec. 2,870 2.870 52,673 2,870 Total or average 276,280 70,413 118,339 85,892 1.636 70,413 100,816 THE CONTROL OP FLOODS BY RESERVOIKS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) 391 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield Flood control Yield in a Passed ■water in a Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights (first 152 second- feet of natural fiow) in aere-feet passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Season- ally stored water in acre-feet formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Year and month 1909 1,352 86,215 5,596 2,520 Jan. 1,222 103,599 8,440 35,296 2,276 Feb. 1,352 116,987 9,344 2,520 Mar. 1,190 1,309 258 131,423 9,042 2,439 375 April 5,041 1,352 369 147,567 9,344 1,955 2 520 520 May G,306 1,309 428 148,428 8,319 3,318 2,439 629 June 6,639 1,352 478 142,293 5,040 3,515 2,520 720 July 6,578 1,352 412 135,538 3,120 3,515 2,520 646 Aug. 6.365 1,309 295 128,857 2,32a 3,403 2,439 485 Sept. 1,352 214 122,530 2,310 2,520 357 Oct. 1,309 139 119,653 2,880 2.439 236 Nov. 1,352 116,978 6,346 3.425 2,520 Dec. Total or average 32,119 15.922 2,593 72,101 38.721 15,706 29,672 3.968 1910 1,352 125,587 9,344 73,110 2,520 Jan. 1,222 110,113 8,435 1,945 2,276 u Feb. 1,352 108,957 9,029 2,520 Mar. 1,309 186 106,998 8,120 2,439 307 April 1,352 250 104,402 5,050 2,520 407 May 1,309 291 101,475 3,560 2,439 478 June U 1,352 337 98,558 2,450 2,520 555 July 1.352 307 95,483 1,710 2,520 506 .^.ug. 1,309 234 92,457 1,370 2.439 385 Sept. 1,352 174 89,633 1,560 2,520 288 Oct. 1,309 113 86,825 1,870 2,439 188 Nov. 1,352 84,198 2,020 2,520 Dec. Total or 15,922 1,892 54,518 75,055 29,672 3,114 average 1911 1,352 81,678 6,441 2,520 Jan. 1.222 109.917 8.440 29,679 2,276 Feb. 1,352 113,822 9,,344 55,275 2,520 Mar. 7,198 1,.309 325 168,683 9,042 4.557 2,439 424 April 11,311 1,352 446 180,421 9,344 8,550 2 520 599 May 12,671 1,309 502 176,008 7,.322 10,018 2,439 708 June 13,155 1,352 537 162,991 5,230 10.444 2,520 793 July 13,094 1,352 446 149,234 3.610 10,444 2,520 692 Aug. 12,612 1,.309 306 135,578 2,830 10,109 2,4.39 500 Sept. 1,352 215 122,5.30 3,140 2,520 357 Oct. 1 s 1,309 139 119,653 2,800 2,439 236 Nov. 1.352 116,978 2,870 2.520 Dec Total or 70,041 15,922 2,916 70,413 84,954 54.152 29,672 4,309 average 392 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first IQA 131,000 acre-feet of capacity loiJ,uuu auie- Flood Yield Flood control control Year and month Run-off at .\zusa in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in water passing Azusa during flood season at rates less than 1,900 Season- ally stored water in acre-feet in a uni- formly con- tinuous supply from over- year storage Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by Ham for prior rights (first 152 second- feet of natural flow) in water passing .■\zu8a during flood season at rates less than 1.900 acre-feet second- acre-feet second- feet in acre-feet in acre-feet feet in acre-feet 1912 .Jan. 2.710 2,710 51,321 2,710 Feb. 2.2.30 2,2^0 49.969 2,230 Mar. 22.900 8,199 48.704 8.199 Anril 18.000 14,701 8,515 2,314 95 62.053 8.515 May 10.900 21,777 8,828 4.273 163 69.991 8,828 June 4,990 19,413 4,990 4.634 182 69.228 4,990 July 3,060 14,597 3,060 4.790 184 65.940 3.060 Aug. 1,960 9,623 1,960 4,790 135 62,502 1,960 S.pt. I,55t) 4,698 1,5.50 4,634 64 59,131 1,550 Oct. 1,830 1,830 55,864 1,830 Nov, 1,730 1,730 54,297 1,730 Dee. 1,760 1,760 52.849 1.706 Total or average 73,620 47.362 25,435 823 47.362 1913 Jan. 2,910 2,910 51.497 2.910 Feb. 13,200 4,753 50.145 4.753 Mar. 10,200 8,447 8,759 57.370 8.759 April 7,140 9,888 7,091 1,547 75 57.459 7,091 May 4,970 8,315 4,970 1,608 93 55.993 4,970 June 2,890 6,614 2,890 1.557 95 54,367 2,890 July 1,690 4,962 1,690 1.607 93 52,737 1,690 Aug. 1,070 3,262 1.070 1.607 68 51.010 1,070 Sept. .893 1,587 893 1.555 32 49.318 893 I) Oct. 910 910 47.749 910 Nov. 2,280 2.280 46,201 2.280 Dec. 2,170 2.170 44,765 2,170 Total or average 50.323 40,386 9.481 456 40.386 I) 1914 Jan. 01,400 6,271 41,989 43,413 6,271 35.050 Feb. 121,000 13,140 8.440 59,505 62.140 8,440 58,284 Mar. 48,000 66,195 9,344 53,083 115,194 9,344 52,388 April 21,400 51.768 9,042 8,291 193 100,110 9,012 May 16,900 55.642 9,344 11,077 274 105.206 9..344 June 9,580 51,847 8 585 12.509 313 102,701 8,585 July 5.570 40,020 5,570 13.258 317 92,040 5.570 Aug. 3,630 26,445 3.630 13.258 238 79,660 3,630 Si-pt. 2,730 12,949 2.730 12.826 123 67,426 2,730 Oct. 2.770 2,770 55,703 2,770 (I Nov. 2,440 2.440 54,137 2,440 Dec. Total or 4,290 4.290 52.689 4.290 average 299,710 72,456 154,577 71,219 1,458 72,456 145.722 THE CONTROL OF FLOODS BY RESERVOIRS. 393 RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield Flood control Yield in a Passed water in a Season- uni- formly con- Evapora- tion Waste Stage of reservoir by dam for prior rights rfirst 152 second- feet of natural flow) in acre-feet passing Azusa during flood season at rates less than 1,900 second- Season- uni- formly con- Evapora- tion Waste Year and ally stored water in tinuous supply from from reservoir surface over spill- way at be- ginning of ally stored waterin tinuous supply from from reservoir surface over spill- way month acre-feet over- year storage in acre-feet in acre-feet month in acre-feet acre-feet over- year storage in acre-feet in acre-feet in acre-feet feet in acre-feet in acre-feet 1912 1,352 114,458 2,710 2,520 Jan. 1,265 111,938 2,230 2,358 Feb. 1,352 109,580 8,199 2,520 Mar. 1,309 238 121,761 8,515 2,439 337 April 1,168 1,352 315 128,470 8,828 2,520 473 May 1,606 1,309 373 127,549 4,990 2,439 565 June 1,660 1,352 426 124,545 3,060 2,520 656 July 1,660 1,352 359 121,369 1.960 2,520 602 Aug. 1,667 1,309 291 118.247 1,550 2,439 456 Sept. 1,352 215 115,352 1,830 2,520 343 Oct. 1,.309 139 112,489 1,7,30 2,439 226 Nov. 1,352 109,824 1,760 2,520 Dec. Total or average 7,761 15,965 2,356 47,362 29,754 3,658 1913 1,352 107,304 2,910 2,520 Jan. 1,222 104,784 4,753 2,276 Feb. 1,352 110,955 8,759 2,520 Mar. 1,309 206 109,876 7,091 2,439 315 April 1,352 274 107,171 4,970 2,520 420 May 1,309 321 104,231 2,890 2,439 493 June 1,352 375 101,299 1,690 2,520 573 July 1352 340 98,206 1,070 2,520 523 Aug. 13M 260 95,163 893 2,439 394 Sept. 1352 196 92,330 910 2,520 297 Oct. - 1,309 127 89,513 2,280 2,439 194 Nov. 1,352 86,880 2,170 2,520 Dec. Total or average 15,922 2,099 40,386 2:1,672 3,209 1914 1 I 1,352 84,360 6,271 20,557 2,520 Jan. 1,222 116,412 8,440 51,500 2,276 Feb. 1,352 175,196 9,344 51,782 2,520 Mar. 5,652 1,309 301 159,550 9,042 3,070 2.439 407 April 8,299 1,352 410 165,992 9,344 5,656 2,520 565 May 9,875 1,309 472 164,807 8,585 7,317 2,439 676 June 10,512 1,352 516 155,370 5,570 7,893 2,520 765 July 10,450 1,352 432 144,192 3,630 7,892 2.520 676 Aug. 10,113 1,309 301 133,104 2 730 7,639 2,439 496 Sept. 1,352 214 122,530 2,770 2,520 357 Oct. 1,309 139 119,653 2 440 2,439 236 Nov. 1,352 116,978 4,290 2.520 Dec. Total or average 54,901 15 922 2 785 72 456 123,839 39,467 29,672 4,178 25—52411 394 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 131,000 acre-feet of capacity IBO.uuu acre- Flood Yield Flood control control Year and month Run-off at Azusa in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in water passing Azusa during flaod season at rates less than 1,900 Season- ally stored water in acre-feet in a uni- formly con- tinuous supply from over- year storage Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights vfirst 152 second- feet of natural flow) in water passing .\zusa during flood season at rates less than 1,900 acre-feet second- acre-feet second- feet in acre-feet in acre-feet feet in acre-feet 1915 Jan. 7,380 4,428 2,632 51,337 4,428 3,029 Feb. 30,200 320 8.412 13,196 49,308 8,412 12,355 Mar. 21,500 8,912 9,344 57,519 9,344 April 17,300 21,068 9,042 3.339 117 68,323 9,042 May 20,400 25,870 9,344 4,256 177 74,618 9,344 June 11,400 32,493 8,967 7,807 238 81,891 8,967 July 7,010 2fi,881 7,010 8,875 254 77,842 7.010 Aug. 3,980 17,752 3,980 8,875 190 70,305 3.980 Sept. 3,270 8,687 3,270 8,592 • 95 62.829 3.270 Oct. 2,770 2,770 55,694 2.770 Nov. 3,010 3,010 54,128 3,010 Dec. 3,580 3,580 9 52,680 3.580 Total or average 131,800 73.157 15,828 41.744 1,071 73.157 15,984 1916 Jan. 148,000 8,759 52,702 51,328 8.759 51,935 Feb.- 39,400 86,539 8,741 99.427 137,282 8.741 99,779 Mar. 34,800 17,771 9,344 18 66,897 9.344 603 April 19,900 43,209 9,042 6,913 174 90,398 9.042 May 10,400 40,980 9,130 9,304 248 95,618 9.130 June 5,830 38,698 5,830 9,314 204 88,764 5.830 July 4,770 29,120 4,770 9,624 264 80,541 4,770 Aug. 3,570 19,232 3,570 9.624 198 72.070 3.570 Sept. 2,810 9,410 2,810 9.314 96 63,667 2.810 Oct. 7.010 6,473 55,638 6.473 Nov. 4,130 537 4,130 7 54,609 4,130 Dec. 13,000 530 5.253 53.169 5,253 Total or average 294,220 77.852 152.147 54.093 1.251 77.852 152.317 1917 Jan. 9,280 8,877 8,172 9,467 60,164 8,172 10,464 Feb. 13,200 518 7.551 49,456 7.551 Mar. 13,600 6,167 9.344 53.883 9,344 April 10,500 10,423 9,042 1,640 73 56,787 9.042 May 8,610 10,168 8,531 1,979 99 56,728 8.531 June 5,270 8,169 5,270 1,935 105 55,179 5.270 July 3,140 6,129 3,140 1,999 99 53.543 3,140 Aug. 2.200 4,031 2,200 1,999 67 51.812 2,200 Sept. 1,510 1,965 1.510 1,935 30 50.115 1,510 Oct. 1.560 1,560 48.514 1.560 Nov. 1,840 1,840 46,994 1,840 Dec. 2,000 2,000 45,558 2,000 Total or average 72,710 60,160 9,467 11.487 473 60.160 10.464 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) 395 feet passed for prior rights, onal storage each year. Maximum flood control reserve 131,000 acre-feet. feet capacity 240,000 acre-feet capacity Flood Yield control Yield in a Passed water in a Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights (first 152 second- feet of natural flow) in acre-feet passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Year and month 1915 1,352 114,458 4,428 5,570 2,520 Jan. 1,222 109,320 8,412 11,720 2,276 Feb. 1,352 117,112 9,344 2,520 Mar. 416 1,309 238 126,748 9,042 2,439 353 April 2,090 1,352 341 132,214 9,344 2,520 494 May 4,759 1,309 414 140,256 8,967 1,326 2,439 603 Jime 5,717 1,352 468 138,321 7,010 2,189 2,520 706 July 5,717 1,352 407 132,906 3,980 2,188 2,520 640 .■^ug. 5,533 1,309 293 127,558 3,270 2,109 2,439 480 Sept 1,352 214 122,530 2,770 2,520 357 Oct. 1,309 139 119,653 3,010 2,439 236 Nov 1,352 116,978 3,580 2,520 Dec. Total or 24,232 15,922 t,514 73,157 17,290 7,812 29,672 3,869 average 1916 1,352 C 114,458 8,759 51,481 2,520 Jan. 1,265 199,698 8,741 99,327 2,358 Feb. 1,352 128,672 9,344 2,340 2,520 C Mar. 4,045 1,309 284 149,268 9,042 1,398 2,439 389 April 6,393 1,352 379 155,900 9,130 3,62o 2,520 541 May 6,484 1,309 430 150,483 5,830 3,819 2,439 633 June 6,639 1,352 480 143,592 4,770 3,946 2,520 724 July 6,639 1,352 412 136,402 3,570 3,945 2,520 650 Aug. 6,425 1,309 295 129,287 2,810 3,832 2,439 486 Sept. 1,352 214 122,530 6,473 2,520 357 Oct. 1,309 131 120,190 4,130 2,439 236 Nov. 1,352 117,515 5,253 141 2,520 Dec. Total or 36,625 15.965 2,625 77,852 153,289 20,566 29,754 4,016 average 1917 1,352 123,201 8,172 12,270 2,520 Jan. 1,222 109,519 7,551 2,276 Feb. 1,352 112,892 9,344 2,520 Mar. 1,309 208 114,628 9,042 2,439 325 April 1,352 276 113,322 8,531 2,520 432 May 1,309 327 110,449 5,270 2,439 508 June 1,352 379 107,502 3,140 2,520 589 July 1,352 345 104,393 2,200 2,520 539 Aug. 1,309 262 101,334 1,510 2,439 408 Sept. 1,352 198 98,487 1,560 2,520 305 Oct. 1,309 127 95,662 1,840 2,439 202 Nov. l,3.i2 93,021 2,000 2,520 Dec. Total or average 15,922 2,122 60,160 12,270 29,672 3,308 396 WATER RESOURCES OP CALIFORNIA, TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood confro! reserve or first 131,000 icre-feet of capacity ISO.uuu acie- Flood Yield Flood control control Year and month Run-off at Azusa in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dan. for prior rights (first 152 second- feet of natural flow) in water passing Azusa during flood season at rates less than 1,900 Season- ally stored water in acre-feet m a uni- formly con- tinuous supply from over- year storage Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in water passing Azusa during flood season at rates les.<: than 1,900 acre-feet second- acre-feet second- feet in in acre-feet feet in acre-feet acre-feet 1918 Jan. 2,020 2,020 44.206 2,020 Feb. 9,330 3,847 42,854 3,847 Mar. 73.200 5,483 9,249 11,341 4/, 115 9,249 3,595 .\pril 17,000 58,093 9,042 9,314 206 106,119 9,042 May 10,000 56,531 8,993 11,216 276 105,858 8,993 June 6,010 46,046 6,010 11,097 292 96,679 6.010 July 3,970 34,657 3,970 11,167 293 86.528 3.970 Aug. 2,840 22,897 2,840 11,467 218 76,012 2.840 Sept. 2,330 11,212 2,330 11,099 113 65.632 2.330 Oct. 2,930 2,930 55.697 2.930 Nov. 3,140 3,140 54,131 3.140 Dec. 4,370 4,370 52,683 4.370 Total or average 137,140 58,741 11,341 65,660 1,398 58.741 3,595 1919 Jan. 3,300 3,300 51,331 3,300 Feb. 4,110 4,110 49.979 4,110 Mar. 6.110 6,110 48,757 6,110 April 6,010 6,010 47,405 6.010 May 3,810 3,810 45.914 3,810 June 1,890 1.890 44,318 1,890 July 1,320 1,320 42,725 1.320 Aug 935 935 41.044 935 Sept. 1,010 1,010 39,393 1.010 Oct. 2,040 2,040 37.854 2.040 Nov. 2,130 2.130 36,331 2.130 Dec. 5,340 5.209 34,913 5.209 Total or average 38,005 37.874 37.874 1920 Jan. 3,260 131 3,260 33,692 3.260 Feb. 12,700 131 5,854 32,340 5.854 Mar. 36.200 6,977 9,344 37,921 9,344 April 25,100 33,833 9,042 5.389 153 63,425 9.042 May 12,600 44,349 9.344 8.776 240 77,838 9.344 June 7,380 38,589 7.349 0,286 264 c 76,737 7.349 July 4,670 29.070 4.670 9,603 270 71, .554 4,070 Aug. 3,200 19.197 3,200 9,603 200 66,191 3,200 Sept. 2,030 9,394 2.030 9.292 102 60,817 2,030 Oct. 2,000 2.000 55,708 2,000 Nov. 2,380 2.380 54,142 2.380 Dec. 2,210 2.210 52,694 2.210 Total or average 113.730 60,683 51,949 1,229 60,683 THE CONTROL OF FLOODS BY RESERVOIRS. 397 RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Flood Yield control Yield in a Passed water in a Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights (first 152 second- feet of natural flow) in acre-feet passing A^usa during flood season at rates less than 1,900 second- feet in acre-feet Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Year and month 1918 1,352 90,501 2,020 2,520 Jan. 1,222 87,981 3,847 2,276 Feb. 1,352 91,188 9,249 2,520 Mar. 6,603 1,309 307 152,619 9,042 1,981 2,439 395 April 8,422 1,352 412 155,762 8,993 3,603 2,520 541 May 8,388 1,309 454 150,105 6,010 3,729 2,439 o33 June 8,668 1,352 496 143,304 3,970 3,854 2,520 724 July 8,606 1,352 422 136,206 2,840 3,854 2,520 650 Aug. 8,329 1,309 297 129,182 2,330 3,727 2,439 486 Sept. 1,352 214 122,530 2,930 2,.520 357 Oct. 1,309 139 119,653 3,140 2,439 230 Nov. 1,352 116,978 4,370 2,520 Dec. Total or average 49,016 15,922 2,741 58,741 20,748 29,672 4,022 1919 1,352 114,458 3,300 2,520 Jan. 1,222 111,938 4,110 2,276 Feb. 1,352 109,662 6,110 2,520 Mar. 1,309 182 107,142 6,010 2,439 310 April 1,352 244 104,393 3,810 2,520 412 May 1,309 284 101,461 1,890 2,439 485 June 1,352 329 98,537 1,320 2,520 561 July 1,352 299 95,456 935 2,520 514 Aug. 1,309 230 92,422 1,010 2,439 387 Sept. 1,352 171 89,590 2,040 2,520 291 Oct. 1,309 109 86,785 2,130 2,439 190 Nov. 1,352 84,156 5,209 2,520 Doc. Total or average 15,922 1,818 37,874 29,6.2 3,150 1920 1,352 81,767 3,260 2,520 Jan. 1,265 79,247 5,854 2,358 Feb. 1,-352 83,735 9.344 2,520 Mar. 1,309 236 108,071 9,042 2,439 311 April 2,766 1,352 339 121.379 9,344 2,520 462 May 3,510 1,309 395 121,653 7,349 2,439 547 June 3,565 1,352 446 118,698 4,670 2,520 635 July 3,627 1,352 395 115,543 3,200 2,520 581 Aug. 3,510 1,309 290 112,442 2,030 2,439 442 Sept. 1,352 214 109,561 2,000 2,520 331 Oct. 1,309 139 106,710 2,,380 2,439 218 Nov. 1,352 104,053 2,210 2,520 Dec. Total or average 16,978 15,965 2,454 60,683 29.754 3,527 398 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 1Qfl 131,000 acre-feet of capacity 1 oU.uiiu am v Flood Yield Flood control control Year and month Run-off at Azusa in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in water passing Azusa daring flood season at rates less than 1.900 Season- ally stored water in acre-feet in a uni- formly con- tinuous STjpply from over- year Storage Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet Passed by dam for prior rights (first 152 second- feet of natural flow) in water passing Azusa during flood season at rates less than 1,900 acre-feet second- acre-feet second feet in acre-feet in acre-feet feet in acre-feel 1921 Jan. 5,160 4.405 51,342 4.405 Feb. 4.490 755 4,490 50,745 4.490 Mar. 15,400 755 7,288 49,523 7.288 April 6,070 8,867 6,070 1,386 67 56,283 6.070 May 15,700 7.414 6,835 1.432 85 54,770 6,835 June 8,9?0 14.762 7,920 3,510 155 62,002 7.920 July 3,830 12.157 3,830 3,978 169 61.399 3.830 Aug. 2,450 8.010 2.450 3.978 121 59.450 2.450 Sept. 1,840 3.911 1.840 3,859 52 57,536 1.840 Oct. 2,040 2.040 55.703 2.040 Nov. 1,800 1.800 54,137 1,800 Dec. 119,000 5.045 38,907 52,689 5,045 39,506 Total or average 186,760 54,013 38.907 18,143 649 54,013 39.506 1922 Jan. 62,100 75,048 9.344 108.425 125.786 9,344 107.332 Feb. 88,900 19,379 8.440 83.060 69.858 8,440 83.316 Mar. 47.800 16,779 9.344 3.196 65.780 9.344 2.882 April 31.400 52.039 9.042 8,334 192 100,002 9,042 May 24,700 65.871 9.344 13,084 303 115,088 9,344 June 14.400 67.840 9.042 16,400 373 118,319 9.042 July 9,100 56.425 8,576 18,735 392 108.104 8,576 Aug. 5,080 37,822 5,080 18.997 287 90.789 5.080 Sept. 3.290 18,538 3.290 18.385 153 72,867 3,290 Oct. 3.110 3.110 55.724 3,110 Nov. 5,310 4,519 54.158 4.519 Dec. 21,500 791 8.456 53.499 8,456 1.990 Total or average 316,690 87.587 194,681 93,935 1.700 87,587 195.520 1923 Jan. 7,130 13.835 6.968 13.042 63,201 6,968 12.056 Feb. 7,830 955 7,791 40.955 7.791 Mar. 7,320 994 7.320 48.772 7.320 April May 8.330 994 8.079 157 8 47.420 8 079 5.480 1,080 5.480 210 12 46.180 5,480 Juno 3.700 858 3.700 204 12 44.584 3,700 July 2,420 642 2,420 212 8 42.987 2,420 Aug. 1,090 422 1.990 212 6 41.304 1,990 Sept. 1,750 204 1.750 204 39.653 1.750 Oct. 1.710 1.710 38.112 1,710 Nov. 1.900 1.960 36.589 1,960 Dec. Total or average 2.130 2,130 35.169 2,130 51.750 51.298 13.042 1.190 46 51,298 12.056 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page 160.) 399 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield • Flood control Yield in a Passed water in a Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet Ly dam for prior rights (first 152 second- feet of natural flow) in acre-feet passing Anisa during flood season at rates less than 1,900 second- feet in acre-feet Season- ally stored waterin acre-feet uni- formly con- tinuous supply from over- year storage in acre-feet Evapora- tion from reservoir surface in acre-feet Waste oyer spill- way in acre-feet Year and month 1921 1,352 101,533 4,405 2,520 Jan. 1,222 99,768 4,490 2.276 Feb. 1,352 97,492 7,288 2,520 Mar. 1,309 204 103,084 6,070 2,439 301 April 1,352 281 100,344 6,835 2,520 403 May 1,309 354 106,286 7,920 2,439 500 June 184 1,352 413 104,407 3,830 2,520 583 July 184 1,352 378 101,304 2,450 2,520 533 Aug. 238 1,309 286 98,251 1,840 2,439 404 Sept. 1,352 214 95,408 2,040 2,520 303 Oct. 1,309 139 92,585 1,800 2,439 198 Nov. 1,352 89,948 5,045 20,952 2,520 Dec. Total or average 606 15,922 2,269 54,013 20,952 29,672 3,225 1922 1,352 180,431 9,344 103,406 2,520 Jan. 1,222 127,261 8,440 79,666 2,276 Feb. 1,352 125,779 9,344 2,562 2,520 Mar. 5,652 1,309 311 159,153 9,042 2,974 2,439 406 April 10,327 1,352 446 175,692 9,344 7,605 2,520 589 May 13,742 1,309 522 180,334 9,042 11,108 2,439 720 June 15,922 1,352 565 171,425 8,576 13,268 2,.520 821 July 16,106 1,352 404 155,340 5,080 13,533 2,520 712 Aug. 15,527 1,309 307 138,575 3,290 13,098 2,439 508 Sept. 1,352 214 122,530 3,110 2,.520 357 Oct. 1,309 141 119,653 4,519 2,439 236 Nov. 1,352 117,769 8,456 5,092 2,520 Dec. Total or average 77,276 15,922 2,970 87,587 190,726 61,586 29,672 4,349 1923 1.352 123,201 6,968 10,928 2,520 Jan. 1,222 109,915 7,791 2,276 Feb. 1,352 107,678 7,320 2,520 Mar. 1303 182 105,1.58 8.079 2.439 305 April 1,352 244 102,665 5,480 2,520 403 May 1,309 288 99,742 3,700 2,439 474 June 1,352 331 96,829 2 420 2,520 549 July 1,352 299 93,760 1,990 2,520 500 Aug. 1,309 232 90,740 1,750 2,439 379 Sept. 1,352 171 87,922 1,710 2,520 288 Oct. 1,309 111 8.5,114 1,960 2,4.39 186 Nov. 1,352 82,489 2,130 2,520 Dec. Tota or average 15,922 1,858 51,298 10,928 29,672 3,084 400 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Continued). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 180,000 acre- 131,000 3 cre-f eat of capacity Flood Yield • Flood control control Run-off at Azusa in acre-feet Passed water in a Passed water Year and month Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights rfirst 152 second- feet of natural flow) in passing Azusa during flood season at rates less than 1,900 Season- ally stored water in acre-feet uni- formly con- tinuous supply from over- year storage Evapora- tion froa reservoir surface in acre-feet Waste over spill- way in acre-feet Stage of reservoir at be- ginning of month in acre-feet by dam for prior rights (first 152 second- feet of natural flow) in passing Azusa during flood season at rates less than 1,900 acre-feet second- acre-feet second- feet in in acre-feet feet in acre-feet acre-feet 1924 Jan. 2,170 2,170 33,817 2.170 Feb. 1,790 1,790 32.465 1,790 Mar. 4.130 3,714 31,200 3,714 .\pril 6.190 416 6,190 59 8 30,264 6,190 May 3,650 349 3,650 61 10 28.814 3,650 June 1,660 278 1.660 59 10 27,276 1,660 July 1,000 209 1,000 61 12 25.753 1,000 .\ug. 756 136 756 61 10 24.153 756 Sept. 744 65 744 59 6 22.579 744 Oct. 873 873 21.103 873 Nov. 1,190 1,190 19,628 1,190 Dec. Total or average 1,780 1,780 18,240 1,780 25,933 25,517 360 56 25,517 1925 Jan. 1,710 1,710 16,888 1,710 Feb. 1.620 1,620 15,536 1,620 Mar. 2,510 2,423 14,314 2,423 April 7,200 87 5,765 4 13,049 5,765 May 3,050 1,518 3,050 285 29 13,086 3,050 June 1,840 1,204 1,840 278 28 11,629 1.840 July 824 898 824 285 24 10,189 824 Aug. 621 589 621 285 16 8.696 621 Sept. 492 288 492 278 10 7,227 492 Oct. 873 873 5,837 873 Nov. 1,010 1,010 4,433 1,010 Dec. 1,650 1,650 3.096 1,650 Total or avemjc 23,400 21,878 1,411 111 21,878 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. "COORDINATED PLAN." OVER- YEAR STORAGE COORDINATED, tions Carried Out on a Daily Basis. mary, see Table 13, page IbO.) 401 Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights, onal storage each year. feet capacity 240,000 acre-feet capacity Yield Flood control Yield in a Passed water in a uni- by dam for prior rights (first 152 second- feet of natural flow) in acre-feet uni- Season- formly con- Evapora- tion Waste Stage of reservoir passing Azusa during flood season at rates less than 1,900 second- Season- formly con- Evapora- tion Waste Year and month ally tinuous from over spill- way at be- ally tinuous from over spill- way stored water in supply from reservoir siirface ginning of stored water in supply from reservoir surface acre-feet over- year storage in acre-feet in acre-feet month in acre-feet acre-feet over- year storage in acre-feet in acre-feet in acre-feet feet in acre-feet in acre-feet 1924 1,352 79,969 2,170 2.520 Jan. 1,265 77.449 1,790 2.358 Feb. 1,352 75,091 3,714 2,520 Mar. 1,309 141 72,987 6,190 2,439 238 April 1,352 186 70,310 3,650 2,520 315 May 1,309 214 67,475 1.660 2,439 369 June 1,352 248 64,667 1,000 2,520 426 July 1,352 222 61,721 756 2,520 385 Aug. 1,309 167 58.816 744 2,439 290 Sept. 1,352 123 56.087 873 2,520 214 Oct. 1,309 79 53.353 1,190 2.439 139 Nov. 1,352 50,775 1,780 2,520 Dec. Total or average 15,965 1,380 25,517 29,754 2,376 1923 1,352 48,255 1,710 2.520 Jan. 1,222 45,735 1,620 2,276 Feb. 1,352 43,459 2,423 2,520 Mar. 1,309 89 41,026 5,765 2,439 171 .\pril 1,352 105 39.851 3,050 2,520 222 May 1,309 131 37,109 1,840 2,439 254 June 1,352 141 34,416 824 2,520 288 July 1,352 117 31,608 621 2,520 256 Aug. 1,309 81 28.832 402 2.439 188 Sept. 1.352 52 26.205 873 2.520 137 Oct. 1,309 28 23,548 1,010 2,439 85 Nov. 1,352 21,024 1,650 2,520 D?c. Total or avcragi^ 15,922 744 21,878 29,672 1,601 402 WATER RESOURCES OF CALIFORNIA. TABLE 13a (Concluded). SAN GABRIEL WATER YIELD UNDER FLOOD CONTROL, SEASONAL AND Monthly Summary of Compute (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Reservoir emptied of seas Maximum flood control reserve or first 180,000 acre- 131,000 acre-feet of capacity Flood Yield Flood control control Run-off Passed water in a Passed water Year and at Azusa in ace-feet Stapeof liy dam for prior passing Azusa Season- ally stored formly Evapora- Waste Stage of by dam for prior passing Azusa month reservoir at be- ginning riahts (first 152 secord- during flood season con- tinuous supply tion from reservoir over spill- way reservoir at be- ginning of month in acre-feet rights (first 152 second- during flood season of month in acre-feet feet of natural flow) in at rates less than 1,900 water in acre-feet from over- year storage surface in acre-feet in acre-feet feet of natural flow) in at rates less than 1,900 acre-feet second- acre-feet second- feet in acre-feet in acre-feet feet in acre-feet 1926 Jan. 1,540 1,540 1,744 1,540 Feb. 7,i)40 5,485 392 5,485 Mar. s.e.w 2.455 3,650 1,G25 3.650 April 00,000 2,455 8,233 383 32 273 8.233 May 13 000 62,807 9,142 12,471 294 59.572 9,142 June 5,500 53,900 5,500 13,006 323 61,785 5,500 July 3.120 40,571 3,120 13,441 321 60,127 3.120 Aug. 2,070 2(i,809 2,070 13,441 239 58,367 2,070 Sept. 1,580 13,129 1,580 13,001 128 56,642 1,580 Oct. 55.049 Nov. Dec. Total or average 107,400 40,320 65,743 1.337 40,320 Total for period, Jan.1, 1897, to Oct.l, 1926 3.731,977 1,513,303 1,103,359 1,091,252 24,063 1,513,303 •1,010.662 Average for period, Jan.1, 1897, to Oct.l, 1926 125,445 50,867 37,088 36,681 809 50,867 ■'33.972 " Those figures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the exact period of analysis. In the eominitat inns from which this table is prepared, the water in storage on Octoler 1, 1926, the end of the period, is less by this amount than on January I, 1897, the beginning of the porinii. i^inee in the computations. this water was released as flood control water during the first flood season of tlieperio These figures contain 61,313 acre-feet total or an average of 2060 aore-feet per season of water contributed from outside the exact period of analysis. In the computations from which this (able is prepared, the water in storage on October 1, 1926, the end of the period, is less by this amount than on .January 1, 1?97, the beginning of the period. A supplementary analj'sis, havingthesaraeamountof wa tor in storage at the beginning and at the end of the period, was made to obtain the exact yield for the period. This gave 22,200, 25,900 and 23,300 acre-feet perseason, respectively, for the flood control water seasonally stored water, and uniformly continuous flow instead of 29,981, 13,809, and 29,686 acre-feet, respectively, that are shown herein. 404 WATER RESOURCES OF CALIFORNIA. TABLE 15a. SAN GABRIEL RESER COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, othe drafts only as required by reservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Aziisa during flood season at rates less than Constant draft from over- year storage (?2 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reser\'oir surface in acre-feet Waste over spillway in acre-feet 1, 900 second- feet in acre-feet 1897 Jan. 3,617 62,650 3,617 11779 1.352 Feb. 19,146 49,519 7.262 4,628 1.222 Mar. 28,623 55,553 9,344 1.352 April 17,519 73.480 9,042 1,309 1,249 234 May 8.851 79,165 8,126 1,352 3,012 343 June 4,033 75,183 4,033 1.309 3,093 396 July 2,343 70,385 2,343 1.352 3,197 447 Aug. 1.613 65,389 1.613 1.352 3,197 393 Sept. 1.226 60,447 1,226 1.309 3,153 290 Oct. 5,564 55,(i95 2,622 1.35? 220 Nov. 1,860 57,0,i5 1,860 1,309 143 Dec. Total or average 1,875 55,613 1.875 1,352 96,270 52,963 16.407 15,922 16.901 2.466 1898 Jan. 2,4.53 .54,261 2,453 1,352 Feb. 2,241 52,909 2,241 1,222 Mar. 2,131 51,687 2,131 1,352 April 1,050 50,335 1,950 1,309 190 May 2,213 48,836 2,213 1352 252 June 1,150 47,23? 1,159 1,309 296 July 672 45.627 672 1,352 343 Aug. 456 43,932 456 1,3.52 313 Sept. 467 42.267 467 1,309 238 Oct. 533 40.720 533 1,352 179 Nov. 580 39,189 580 1,309 115 Dec. Tobl or average 832 37.765 832 1,352 15.687 15.687 15,922 1.926 1899 .Ian. 1,414 36,413 1.414 1,3.52 Fell. 1,244 35,061 1.244 1,222 Mar. 1,623 33.839 1,623 1.352 April r,262 32,487 1,262 1.309 149 May 842 31.029 842 1.352 194 June 565 29.483 565 1.309 224 July 221 27.950 221 1,352 260 Aug. 295 26,338 295 1,352 234 Sept 220 24.752 220 1,3P9 175 Oct. 683 23,268 683 1.352 129 Nov. 847 21,787 847 1.309 83 Dec. Total or average 1.247 20,395 1,247 1.352 10.463 10.463 15,922 1 1.448 THE CONTROL OF FLOODS BY RESERVOIRS. 405 VOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131.000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each Slimmer to a level that would maintain constant draft through critical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reseri-oir surface in acre-feet Waste over spillway in acre-feet Year and month 1,900 second- feet in acre-feet 1897 49,122 3,617 1,107 Jan. 48,015 7,262 9,778 999 Feb. 49.122 9,344 18,172 1,107 Mar. 49,122 9,042 5,983 1,071 188 April 50,357 8,126 1,107 260 Maj 49,715 4,033 1,071 305 June 48.339 2,343 1,107 357 July 46,875 1,613 1,107* 329 Aug. 45,439 1,226 1,071 250 Sept. 44,118 2,622 1,107 190 Oct. 45,763 1,860 1,071 127 Nov. 44,565 1,875 1,107 Dec. Total or average 52,963 33,933 13,032 2,006 1898 43,458 2,453 1,107 Jan. 42,351 2,241 999 Feb. 41,352 2,131 1,107 Mar. 40,245 1,950 1,071 165 April 39,00" 2,213 1,107 222 May 37,680 1,159 1,071 260 June 36,349 672 1,107 299 July 34,943 456 1,107 274 Aug. 33,562 467 1,071 210 Sept. 32,281 533 1,107 157 Oct. 31,017 580 1,071 101 Nov. 29,845 832 1,107 Dec. Total or average 15.687 13,032 1,688 1899 28,738 1,414 1,107 Jan. 27,631 1,244 999 Feb. 26,632 1,623 1,107 Mar. 25,525 1,262 1,071 129 April 24,325 842 1.107 171 May 23,047 565 1.071 196 June 21,780 221 1,107 226 July 20,447 295 1,107 204 Aug. 19,136 220 1,071 n 153 Sept. 17,912 683 1,107 113 Oct. 16,692 847 1.071 71 Nov. 15,550 1,247 1.107 Dec. Total or average 10,463 13,032 1,263 406 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a level that would maintain constant draft through critica period; constant draft of 22 3econd-feet maintained, other drafts only as required by reservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage {22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1,900 second- feet in acre-feet 1900 Jan. 1.968 19,043 1,968 1,352 Feb. 1,111 17,691 1,111 1,222 Mar. 1,230 16,469 1,230 1,352 April 1,012 15,117 1,012 1,309 95 May 2,275 13,713 2,275 1.352 121 June 893 12,240 893 1,309 135 July 309 10,796 369 1,352 149 Aug. 246 9,295 246 1,352 123 Sept. 238 7,820 238 1,309 85 Oct. 307 6,426 307 1,352 56 Nov. 11,068 5,018 1,058 1,309 32 Dec. 1,269 13,687 1,269 1,352 Total or average 21,986 11,976 15,922 796 1901 Jan. 10,391 12,.335 6,061 1,352 Feb. 38,709 14,713 8,350 1,222 Mar. 13,589 43,850 9,138 1,352 April 6,545 46,^49 6,545 1,300 181 May 7,440 45,459 6,990 1,352 ?40 June 3,749 44,317 3,749 1,309 286 July 1,845 42,722 1,845 1,352 329 Aiig. 1.240 41,041 1,240 1,352 300 Sept. 1,012 39.389 1,012 1,309 230 Oct. 1,476 37,850 1,476 1,352 171 Nov. 1,904 36,327 1,904 1,309 109 Dec. 1,860 34,909 1.'560 1,352 Total or average 89,560 50,570 15,922 1,846 1902 Jan. 1,722 33,557 1,722 1.352 Feb. 2,055 32,206 2,055 1.222 Mar. 6,088 30,983 5,590 1,352 April 3.928 30,129 3,928 1,309 141 May 2,308 28,679 2,398 1,352 184 June I.IOO 27,143 1,190 1,309 214 July 676 25,620 676 1,352 246 Aug. 430 24,022 430 1,352 222 Sept. 298 22,448 298 1,309 167 Oct. 430 20,972 430 1,352 123 Nov. 1,131 19,497 1,131 l,30f 77 Dec. 1.968 18,111 1.968 1,352 Total or average 22.314 21.816 16.922 1,374 THE CONTROL OF FLOODS BY RESERVOIRS. 407 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood Stage of reservoir at _ beginning of month in acre-feet control water Constant Year and month Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than draft from over- year storage (18 second- feet) in acre-feet Seasonally ptored water in acre-feet Evaporation from reservoir surface in acre-feet Waste ove'' spillway in acre-feet 1.900 second- feet in acre-feet 1900 14,443 1,968 1,107 Jan. 13,336 1,111 999 Feb. 12,337 1,230 1,107 Mar. 11,230 1,012 1,071 77 April 10,082 2,275 1.107 99 May 8.876 893 1,071 113 June 7,092 369 1,107 121 July 6,464 246 1,107 95 Aug. ■ 5,262 238 1,071 63 Sept. 4,128 307 1,107 40 Oct. 2,981 1,058 1,071 36 Nov 11.884 1.269 1,107 Dec. Total or average 11,976 13,032 644 1901 10,777 6,661 1,107 Jan. 13,400 8,350 999 Feb. 42,760 9,138 1,107 Mar. 46,104 6.545 1.071 178 April 44,855 6,990 1,107 246 May 43,952 3,749 1,071 284 June 42,597 1,845 1,107 329 July 41,161 1,240 1,107 301 Aug. 39,753 1,012 1,071 232 Sept. 38,450 1,476 1,107 173 Oct. 37,170 1,904 1,071 111 c Nov. 35,988 1,660 1,107 Dec. Total or average 50,570 13.032 1,854 1902 34,881 1,722 1,107 Jan. .33,774 2,055 999 Feb. 32,775 5,590 1,107 Mar. 32,166 3,928 1,071 147 April 30,948 2,398 1,107 194 May 29,647 1,190 1,071 226 June 28,350 676 1,107 262 July 26,981 430 1,107 238 Aug. 25,636 298 1,071 178 Sept. 24,387 430 1,107 133 Oct. 23,147 1,131 1,071 85 Nov. 21,991 1,968 1,107 Dec. Total or average 21,816 13,032 1,463 408 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a leve 1 that would maintain constant draft through critical period; constant draft of 22 second- feet maintained, other drafts only as required by reservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates leas than Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reser\'oir surface in acre-feet Waste over spillway in acre-feet l,900second- feet in acre-feet 1903 Jan. 9,100 16,759 2,536 1,352 Feb. 5,665 21,971 5,497 1,222 Mar. 15,802 20,917 7,898 1,352 April 47,127 27,469 9,042 1,309 180 May 13,343 64,065 9,116 1,352 307 June 5,653 66,633 5,653 1,309 1,012 365 July 2,644 63,947 2,644 1,352 1.107 421 Aug. 1,783 61,067 1,783 1,352 1.045 379 . Sept. 1,488 58,291 1,488 1,309 1.071 288 C Oct. 1,476 55,623 1,476 1,352 214 Nov. 1,428 54,057 1,428 1,309 139 Dec. 1,476 52,609 1,476 1,352 Total or average 106,085 50,037 15,922 4.235 2.293 1904 Jan. 1,500 51,257 1,500 1.352 I'et. 2,744 49,905 2.177 1,205 iMar. 6,813 49,207 4,724 1,352 April 5,337 49,944 5,337 1,309 188 May 4,089 48,447 4,089 1,352 250 June 1,517 46,845 1,517 1,309 296 July 861 45,240 861 1,352 343 Aug. 793 43,545 793 1,352 313 Sept. 643 41,880 643 1,309 238 Oct. 738 40,333 738 1,352 179 Nov. 762 38,802 762 1,309 115 Dec. 1,039 37,378 1,039 1,352 Total or average 26,836 24,180 15,965 1.922 1905 Jan. 2,251 36,026 2,251 1,352 Feb. 25,880 34,674 8,206 1,222 Mar. 7,5,140 51,126 9,281 13,658 1,352 April 19,580 101,975 9,042 1.309 5.949 303 May 17,090 104,952 9,344 1,352 8,237 411 June 8,271 102,698 7,960 1,309 9,875 470 July 5,103 91.355 5,103 1,352 10,266 512 Aug. 2,631 79,225 2,631 1,352 10,266 432 Sept. 1,869 67,175 1.869 1,309 9.935 300 Oct. 1,770 55,631 1,770 1.352 214 Nov. 2.660 54,065 2,660 1,309 139 Dec. 2,470 52,617 2.470 1,352 Total or average 164,715 62,587 13,658 15,922 54,528 2,781 THE CONTROL OF FLOODS BY RESERVOIRS. 409 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reser\ oir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 aecond-feet maintained, other drafts only as required by reservoir operating diagram Flood control Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1,900 second- feet in acre-feet 1903 20,884 2,536 1,107 Jan. 26,341 5,497 999 Feb. 25,510 7,898 1,107 Mar. 32.307 9,042 11,429 1,071 192 April 57,700 9,116 1,107 61 286 May 60,473 5,653 1,071 892 345 June 58,165 2,644 1.107 922 397 July 55,739 1,783 1,107 922 361 Aug. 53,349 1,488 1,071 952 272 Sept. 51,054 ],476 1,107 839 202 Oct. 48,906 1,428 1,071 131 Nov. 47,704 1,476 1,107 Dec. Total or average 50.037 11,429 13,032 4,588 2,186 1904 46,597 1.500 1,107 Jan. 45,490 2.177 1,035 Feb. 45,022 4,724 1,107 Mar. 46,004 5,337 1,071 178 April 44,755 4,089 1,107 240 May 43,408 1,517 1,071 282 June 42,055 861 1,107 327 July 40,621 793 1,107 297 Aug. 39.217 643 1,071 230 Sept. 37,916 738 1,107 171 Oct. 36,638 762 1.071 111 Nov. 35,456 1,039 1.107 Dec. Total or average 24,180 13,068 1,836 1905 34,349 2,251 1.107 Jan. 33,242 8,200 795 999 Feb. 49,122 9,281 64,752 1,107 Mar. 49,122 9,042 7,463 1,071 188 April 50.938 9,344 1,107 270 May 57,307 7,960 1,071 238 333 June 55,976 5,103 1,107 369 389 July 54,111 2.631 1,107 369 357 Aug. 52.278 1,869 1,071 357 270 Sept. 50,580 1.770 1,107 401 202 Oct 48,870 2,660 1,071 131 Nov. 47,668 2,470 1,107 Doc. Total or average 62,587 73,010 13,032 1,734 2,140 26—52411 410 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yeady sum Height of dam 383 feet. Capacity of reservoir 180.000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a lovt 1 that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, othe drafts only as required by reservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in aore-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1.900 second- feet in acre-feet 1906 Jan. 4,240 51,265 3,633 1.352 Feb. 3,960 50,520 3,960 1.222 Mar. 129,000 49,298 7,.561 23,905 1.352 April 34,000 145,420 9,042 15.432 1,309 13,028 357 May 21,000 140,852 9,344 1,352 15,553 498 June 15,500 135,105 9,042 1,309 17,843 569 July 9,350 121,842 8,664 1.352 20,527 609 Aug. 4,490 100,040 4,990 1,352 20,774 488 Sept. 2,840 77,420 2.840 1,309 20,043 315 Oct. 2,450 55,759 2.450 1,352 214 Nov. 2,400 54,193 2,400 1,309 139 Dec. 11,000 52,745 4.030 1,352 Total or average 241,430 67.456 39.397 15,922 107,768 3,189 1907 Jan. 58,400 58,903 9.217 51.921 1,352 Feb. 47,100 54,873 8.439 29.904 1,222 Mar. llii,000 02,408 9,344 45.814 1,352 April 58,100 121,898 9,042 1,309 9,221 375 May 21,500 100,351 9,344 1,352 19.487 539 June 15,100 151,129 9,042 1,309 21,773 609 July 8,300 133,490 7,920 1,352 24,406 642 Aug. 5,390 107,476 5.390 1,352 24.651 402 Sept. 3,580 81,011 3,580 1,309 23,737 321 Oct. 4,090 55,044 4,090 1,352 214 Nov. 3,800 54,078 3,800 1,309 139 Dec. 3,000 52,630 3,600 1,352 Total or average 345,320 82,808 127,639 15,922 123,335 3..301 1908 Jan. 11,100 51,278 4.973 5,543 1.352 Feb. 15,000 50,510 8.741 4,616 1,205 Mar. 12,700 50,888 9,2,i5 1.352 April i),280 52,981 8,056 1,309 196 \lay 7,190 52,100 7,139 1,352 262 June 4,190 50,537 4,190 1,309 309 July 2,560 48.(>19 2,560 1,352 359 Aug. 2,210 47,208 2,210 1.352 325 Sept. 1,820 45.531 1,820 1,300 252 Oct. 2,070 43,970 2.070 1,352 186 Nov. 1,960 42.432 1.960 1,309 123 Dec. 2.870 41,000 2,870 1.352 Tot-»l or average 72.950 50,444 10,159 15,965 2.012 THE CONTROL OF FLOODS BY RESERVOIRS. 411 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE tions Carried out on a Daily Basis. mary, sec Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a level that wojU maintain constant draft through cri tical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control water Constant Year and month Stage of reservoir at licginning iif month ill acre-feet Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1,900 second- feet in acre-feet 1906 46,561 3,633 1,107 Jan. 46,061 3,960 999 Feb. 45,062 7,561 69,126 1,107 Mar. 96,268 9,042 62,426 1,071 224 April 58,105 9,344 1,107 123 295 May 68,236 9,042 1,071 2,439 377 June 70,807 8,664 1,107 4,242 442 July 65,702 4,490 1,107 4.488 391 Aug. 59,716 2,840 1,071 4,283 286 Sept. 54,076 2,450 1,107 3,801 204 Oct. 48,964 2,400 1,071 131 Nov. 47,762 4,030 5,103 1,107 Dec. Total or average 67,456 136,655 13,032 19,376 2,350 1907 49,122 9,217 48,076 1,107 Jan. 49,122 8,439 37.662 999 Feb. 49,122 9,344 98,043 1,107 Mar. 56,628 9,042 44,649 1,071 100 April 60,070 9,344 1,107 430 303 May 70,386 9,042 1,071 2.915 385 June 72,073 7,920 1,107 4,610 448 July 60,348 5,390 1,107 4,733 395 Aug. 60,113 3.580 1,071 4,581 290 Sept. 54,171 4,090 1,107 3.960 204 Oct. 48,900 3,800 1,071 131 Nov. 47,698 3,600 1,107 Dec. Total or average 82,808 228,430 13,032 21,229 2.352 1908 46,591 4.973 2.489 1,107 Jan. 49,122 8,741 5.224 1,035 Feb. 49,122 9,255 2,338 1,107 Mar 49.122 8.656 305 1.071 190 April 48,180 7,139 1,107 250 May 40,874 4,190 1,071 295 June 45,508 2,.560 1,107 343 July 44,058 2,210 1,107 313 Aug. 42.638 1,820 1,071 240 Sept. 41.327 2.070 1,107 180 Oct. 40.040 1,960 1,071 117 Nov. 38,852 2,870 1,107 Dec. Total or average 56,444 10,356 13.068 1.928 412 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, othe r drafts only as required by eservoir operating diagram Flood Year and month Run-off _ at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water pissing Azusa during flood season at rates less than Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1,900 second- feet in acre-feet 1909 Jan. 25,500 39,648 5,596 8,681 1,352 Feb. 59,400 49,519 8,440 41,897 1,222 Mar. 26,300 57,360 9,344 1,352 April 28,000 72,964 9.042 1,309 1,190 258 May 15,200 89,165 9,344 1,352 5,041 369 June 8,570 88,259 8,319 1,309 6,306 428 July 5,040 80,467 5,040 1,352 6,639 478 Aug. 3,120 71,998 3,120 1.352 6,578 412 Sept. 2,320 63,656 2.320 1,309 6,365 295 Oct. 2,310 55,687 2,310 1,352 214 Nov. 2,880 54,121 2,880 1.309 139 Dec. 20,900 52.673 6,346 1,682 1,352 Total or average 199,540 72,101 52,260 15,922 32,119 2,593 1910 Jan. 69,500 64,193 9,344 72,870 1,352 Feb. 11,500 50,127 8,435 2,292 1,222 Mar. 9,590 49,678 9,029 1,352 April 8,270 48,887 8,120 1,303 186 May 5,050 47,542 5,050 1,352 250 June 3,560 45,940 3,560 1,309 291 July 2,450 44,340 2,450 1,352 337 Aug 1,710 42,051 1,710 1,352 307 Sept. 1,370 40,992 1,370 1,309 234 Oct. 1,560 39,449 1,560 1,352 174 Nov. 1,870 37,923 1,870 1,309 113 Dec. Total or average 2,020 36,501 2,020 1,352 118,450 54,518 75,162 15,922 1,892 1911 Jan. 37.200 35,149 6.441 6,949 1,352 Feb. 44,300 57,607 8,440 38,010 1,222 Mar. 122,000 54,235 9,344 65.857 1,352 April 28,200 109,682 9,042 1,309 7.198 325 May 16,600 120,008 9,344 1,.352 11,311 446 June 7.500 114,155 7,322 1,309 12,671 502 July 6,230 99.851 5,230 1,352 13,155 537 Aug. 3,610 84,807 3.610 1,352 13.094 446 Sept. 2.8,30 69,915 2,830 1,309 12,612 306 Oct. 3,140 55,688 3,140 1,352 215 Nov. 2,800 54,121 2,800 1,309 139 Doc. Total or average 2,870 52,673 2.870 1,352 276,280 70,413 100,816 15,922 70,041 2.916 THE CONTROL OF FLOODS BY RESERVOIRS. 413 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through cr tical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet 1 Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1,900 second. feet in acre-feet 1909 37,745 5,596 7,420 1,107 Jan. 49,122 8,440 49,961 999 Feb. 49,122 9,344 15,849 1,107 Mar. 49,122 9,042 12,977 1,071 192 April 53,840 9,344 1,107 276 May 58,313 8,319 1,071 476 337 June 56,680 5,040 1,107 553 393 July 54,627 3,120 1,107 553 357 Aug. 52,610 2,320 1,071 535 272 Sept. 50,732 2,310 1,107 527 205 Oct. 48,893 2,880 1,071 133 Nov. 47,689 6,346 5,208 1,107 Dec. Total or average 72,101 91,415 13,032 2,644 2,165 1910 55,928 9,344 65,855 1,107 Jan. 49,122 8,435 2,147 999 Feb. 49,041 9,029 1,107 Mar. 48,495 8,120 1,071 186 April 47,388 5,050 1,107 248 May 46,033 3,560 1,071 292 June 44,670 2,450 1,107 341 July 43,222 1,710 1,107 311 Aug. 41,804 1,370 1,071 238 Sept. 40,495 1,560 1,107 178 Oct. 39,210 1,870 1,071 117 Nov. 38,022 2,020 1,107 Dec. Total or 54,518 68,002 13,032 1,911 average 1911 36,915 6,441 10,419 1,107 Jan. 56,148 8,440 41,887 999 Feb. 49,122 9,344 99,133 1,107 Mar. 61,538 9,042 24,943 1,071 194 April 54,488 9,344 1,107 280 May 60,357 7,322 1,071 892 345 June 58,227 5,230 1,107 984 397 July 55,739 3,610 1,107 922 361 Aug. 53,349 2,830 1,071 952 272 Sept. 51,054 3,140 1,107 867 201 Oct. 48,876 2,800 1,071 141 Nov. 47,664 2,870 1,107 Dec. Total or average 70,413 176,382 13,032 4,617 2,194 414 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir em ptied each summer to a leve 1 that would maintain constant draft throu gh critical period; consta it draft of 22 second-feet maintained, othci drafts only as required by reservoir operating diagram Flood Year and month Run-off _ at Azusa in acre-feet Stage of reservoir at _ beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than 1.900 second- feet in acre-feet Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1912 Jan. 2,710 51,321 2,710 1,352 Feb. 2,230 49,969 2,230 1265 Mar. 22,900 48,704 8,199 1,352 April 18,000 62,053 8,515 1,309 238 May 10,900 69,991 8,828 1,352 1,168 315 June 4,990 69.228 4,990 1.309 1,606 373 July 3,000 65,940 3.060 1,352 1,660 426 Aug. 1,960 62,502 1.960 1,352 1,660 359 Sept. 1,5.50 59,131 1.550 1,309 1,067 291 Oct. 1,830 55,864 1.830 1,352 215 Nov. 1,730 54,297 1.730 1,309 139 Dec. 1.760 52,849 1.760 1.352 Total or average 73,620 47,362 15.965 7,761 2.356 1913 Jan. 2,910 51,497 2,910 1.352 Feb. 13,200 50,145 4,753 1.222 Mar. 10.200 57,370 8,759 1.352 April 7,140 57,459 7,091 1.309 206 May 4,970 55,993 4,970 1,352 274 June 2,890 54.367 2.890 1,309 321 July 1,690 52.737 1.690 1,352 375 Auk. 1,070 51.010 1.070 1,352 340 Sept. 893 49,318 893 1.309 260 Oct. 910 47.749 910 1,.352 196 Nov. 2,280 46.201 2,280 1,309 127 Dec. 2,170 44,765 2,170 1.352 Total or avcroKC 50,323 40.386 15.922 2,099 1914 Jan. 61,400 43.413 6,271 35,050 1,352 Feb. 121,000 62.140 8.440 58,284 1.222 Mar. 48,000 115.194 9.344 52,388 1.352 April 21,400 100.110 9.042 1.309 5,652 301 May 16.900 105,206 9.344 1.352 8,299 410 June 9.580 102,701 8.585 1,.309 9,875 472 July 5.570 92,040 5.570 1,.3.52 10,512 516 AUR. 3.630 79,000 3.630 1,352 10.450 432 Sept. 2.7.30 67.426 2.730 1,309 10.113 301 Oct. 2.770 55.703 2.770 1,352 214 Nov. 2,440 .54.137 2.440 1,309 139 Dec. 4,290 52.689 4.290 1,352 Total or average 290,710 72,456 145,722 15,922 54.901 2.785 THE CONTROL OF FLOODS BY RESERVOIRS. 415 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throuqhout flood season Reser\ oir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control Year and Stage of reser^'oir at beginning of month in acre-feet water Constant month Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1,900 second- feet in acre-feet 1912 46,557 2,710 1,107 Jan. 45,450 2,230 1,035 Feb. 44,415 8,199 9,208 1,107 Mar. 48,801 8,515 3,852 1,071 192 April 53,171 8,828 1,107 268 May 53,868 4,990 1,071 321 June 52,476 3,060 1,107 375 July 50,994 1,960 1,107 341 Aug 49,546 1.550 1,071 262 Sept 48,213 1,830 1,107 196 Qjt. 46,910 1,730 1,071 127 Nov 45,712 1,760 1,107 Dec Total or average 47,362 13,060 13,068 2,082 1913 44,605 2,910 1,107 Jan. 43,498 4,753 1,824 999 Feb. 49,122 8,759 863 1,107 Mar. 48.593 7,091 1,071 186 April 47,385 4,970 1,107 248 May 46.030 2,890 1,071 292 June 44,667 1,690 1,107 341 July 43,219 1,070 1,107 311 Aug. 41,801 893 1,071 238 Sept. 40,492 910 1,107 178 Oct. 39,207 2,280 1,071 115 Nov. 38,021 2,170 1,107 Dec. Total or average 40,386 2,687 13,032 1,909 1914 36,914 6,271 30,155 1,107 Jan. 60,781 8,440 60,518 999 Feb. 111,824 9,344 100,251 1,107 Mar. 49,122 9,042 6,877 1,071 190 April 53,.342 9,344 1,107 278 May 59,513 8,585 1,071 714 343 June 58,380 5,570 1,107 984 397 July 55,892 3,630 1,107 984 361 Aug. 53,440 2,730 1,071 952 272 Sept. 51,145 2,770 1,107 920 204 Oct. 48,914 2,440 1,071 131 Nov. 47,712 4,290 1,107 Dec. Total or average 1 72,456 197.801 13,032 4,554 2,176 416 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reser^'oir emptied each summer to a leve Ithat would maintain constant draft through critical period; constant draft of 22 second-feet maintained, other drafts only af required by reservoir operating diagram I Flood Year and month Run-off at Azusa in acre-feet Stage of reseri-oir at beginning of month in aere-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage (22 second- feet) in aere-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet l,900second- feet in acre-feet 1915 Jan. 7,380 51,-337 4.428 3,629 1,352 Feb 30,200 49.308 8.412 12,355 1,222 Mar. 21,500 57,519 9,344 1,352 April 17.300 68,323 9.042 1,309 416 238 May 20,400 74,618 9,344 1,352 2,090 341 June 11,400 81.891 8,967 1,309 4.759 414 July 7.010 77,842 7.010 1,352 5,717 468 Aug. 3,980 70,305 3.980 1,352 5,717 407 Sept. 3,270 62,829 3.270 1,309 5,533 293 Oct. 2,770 55.694 2.770 1,352 214 Nov. 3,010 54,128 3.010 1,309 139 Dec. 3,580 52,680 3,580 1,352 Total or average 131,800 73.157 15,984 15,922 24,232 2,514 1916 Jan. 148,000 51,328 8,759 51,935 1,352 Feb. 39,400 137,282 8,741 99,779 1,265 Mar. 34,800 66,897 9.344 603 1.352 April 19,000 90,398 9,042 1,309 4.045 284 May 10,400 95,618 9.130 1,352 6.393 379 June 5,830 88,764 5,830 1,309 6.484 430 July 4,770 80,541 4,770 1,352 6.6.39 480 Aug. 3,570 72,070 3,570 1,352 6,639 412 Sept. 2,810 63,667 2.810 1,309. 6,425 295 Oct. 7,010 55.638 6.473 1.352 214 Nov. 4,130 54,609 4.130 1,309 131 Dec 13,600 53.169 5.253 1.352 Total or average 294.220 77.852 152.317 15,965 36,625 2,625 1917 Jan. 9,280 60.164 8.172 10,464 1.352 Feb. 13.200 49.456 7,551 1.222 Mar. 13.600 53.883 9,344 1.352 April May 10,500 56.787 9,042 1,309 208 8,610 56.728 8,531 1,352 276 June 5,270 5.5,179 5.270 1,309 327 July 3.140 53,543 3,140 1,352 379 Aug. 2,200 51.812 2,200 1.352 345 Sept. 1,510 50.115 1,510 1,.309 262 Oct. 1.560 48.544 1.560 1,352 198 Nov. 1.840 46.994 1,840 1,309 127 Dec. 2.000 45.558 2,000 1,352 Total or average 72.710 60.160 10,464 15,922 2,122 THE CONTROL OF FLOODS BY RESERVOIRS. 417 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through cr tical period: constant draft of 18 second-feet maintained, other drafts only as required by- reservoir operating diagram Flood control Year and Stage of reservoir at Passed by dam water passing Azusa during Constant draft from over- Seasonally stored Evaporation from_ Waste over month beginning of month in acre-feet for prior rights in acre-feet flood season at rates less than 1,900 second- feet in acre-feet year storage (18 second- fee tl in acre-feet water in acre-feet reservoir surface in acre-feet spillway in acre-feet 1915 46,605 4,428 1,107 Jan. 48,450 8,412 20,117 999 Feb. 49,122 9,344 11,049 1,107 Mar. 49,122 9,042 4,689 1,071 188 April 51,432 9,344 1,107 276 May 61,105 8,967 1,071 1,011 349 June 61,107 7,010 1,107 1,721 408 July 57,871 3,980 1,107 1,721 369 Aug. 54,674 3,270 1,071 1,666 276 Sept. 51,661 2,770 1,107 1,499 204 Oct. 48,851 3,010 1,071 131 Nov. 47,649 3,580 1,107 Dec. Total or average 73,157 35,855 13,032 7,618 2,201 1916 46,542 8,759 52,105 1,107 Jan. 132,571 '8,741 100,650 1,035 Feb. 61,545 9,344 36,772 1,107 Mar. 49,122 9,042 7,311 1,071 190 April 51,408 9,130 1,107 262 May 51,309 5,830 1,071 311 June 49,927 4,770 1,107 363 July 48,457 3,570 1,107 331 Aug. 47,019 2,810 1,071 254 Sept. 45,694 6,473 1,107 190 Oct. 44,934 4,130 1,071 127 Nov. 43,736 5,253 1,997 1,107 Dec. Total or average 77,852 198,835 13,068 2,028 1917 48,979 8,172 98 1,107 Jan. 48,882 7,551 4,410 999 Feb. 49,122 9,344 3,149 1,107 Mar. 49,122 9,042 370 1,071 190 April 48,949 8,531 1,107 252 May 47,669 5,270 1,071 299 June 46,299 3,140 1,107 347 July 44,845 2,200 1,107 317 Aug. 43,421 1,510 1,071 242 Sept. 42,108 1,560 1,107 182 Oct. 40,819 1,840 1,071 117 Nov. 39,631 2,000 1,107 Dec. Total or avcrasc 60,160 8,027 13,032 1,946 418 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control bv reservoir operating diagram Reser\'oir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than l,900second- feet in acre-feet Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1918 Jan. 2,020 44.206 2,020 1,352 Feb. 9,330 42,854 3,847 1,222 Mar. 73,200 47,115 9,249 3,595 1,352 April 17,000 106,119 9,042 1,309 6,603 307 May 10,000 105,858 8.993 1,352 8,422 412 June 6,010 96,679 6,010 1,309 8,388 454 July 3,970 86,528 3.970 1,352 8.668 496 Aug. 2,840 76,012 2,840 1.352 8,606 422 Sept. 2,330 65,632 2,330 1,309 8,329 297 Oct. 2,930 55,697 2,930 1,352 214 Nov. 3,140 54,131 3,140 1,309 139 Dec. 4,370 52,683 4,370 1,352 Total or average 137,140 58,741 3,595 15.922 49.016 2,741 1919 Jan. 3,300 51,331 3,300 1,352 Feb. 4,110 49,979 4,110 1,222 Mar. 6,110 48,757 6.110 1,352 April 6.010 47,405 6.010 1,309 182 May 3,810 45,914 3,810 1,352 244 June 1,890 44,318 1,890 1.309 284 July 1,320 42,725 1,320 1.352 329 Aug. 935 41,044 935 1,352 299 Sept. 1,010 39,393 1,010 1,309 230 Oct. 2,040 37,854 2,040 1.352 171 Nov. 2,130 36.331 2,130 1,309 109 Dec. 5,340 34,913 5,209 1,352 Total or average 38,005 37.874 15,922 1.848 1920 Jtm. 3,260 33.692 3,260 1,352 Feb. 12,700 32.340 5.854 1.265 Mar. 36,200 37,921 9,344 1.352 April May 25.100 63,425 9.042 1.309 236 12,600 77,938 9.344 1,352 2.766 339 Juno 7.380 76.737 7.349 1,309 3.510 395 July 4,670 71,554 4,670 1,352 3.565 446 Aug. 3,200 66.191 3,200 1.352 3.627 395 Sept. 2.030 60.817 2,030 1,300 3.510 290 Oct. 2,000 55.708 2.000 1,352 214 Nov. 2.380 51.142 2.380 1.309 139 Dec. 2.210 52,694 2.210 1,352 Total or average 113.730 60,683 15.965 16.978 2.454 THE CONTROL OF FLOODS BY RESERVOIRS. 419 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reserv oir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control Year and Stage of reservoir at _ beginning of montii ■ n acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1,900 second- feet in acre-feet 1918 38,524 2,020 1,107 Jan. 37,417 3,847 999 Feb. 41,901 9,249 55,023 1,107 Mar. 49,122 9,042 5,345 1.071 190 April 50,474 8,993 1.107 258 May 50,116 6,010 1,071 305 .Tune 48,740 3,970 1.107 359 July 47,274 2,840 1,107 327 Aug. 45,840 2,330 1.071 252 Sept. ■♦4,517 2,930 1.107 188 Oct. 43,222 3,140 1.071 121 Nov. 42,030 4,370 1.107 Dec. Total or average 58,741 60,968 13,032 2,000 1919 40,923 3,300 1,107 Jan. 39,816 4,110 999 Feb. 38,817 6,110 1,107 Mar. 37,710 6,010 1,071 161 April 36,478 3,810 1.107 214 May 35,157 1,890 1.071 250 June 33,836 1,320 1.107 290 July 32,439 935 1.107 262 Aug. 31,070 1,010 1.071 200 Sept 29,799 2.040 1.107 149 Oct. 28,543 2,130 1.071 97 Nov. 27,375 5.209 1.107 Deo. Total or average 37.874 13.032 1,623 1920 26.399 3,260 1.107 Jan. 25,292 5,854 1,035 Feb. 31,103 9,344 7.730 1,107 Mar. 49,122 9,042 12.388 1,071 190 April 51,531 9,344 1,107 266 May 53,414 7,349 1,071 319 June 52,055 4,670 1,107 371 July 50.577 3,200 1.107 339 Aug. 49,131 2,030 1,071 260 Sept 47,800 2,000 1.107 196 Oct. 46,497 2,380 1.071 127 Nov. 45,299 2,210 1,107 Dec. Total or average 60,683 20,118 13.068 2,068 420 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood confrol by reservoir operating diagram Reservoir en ptied each summer to a leve 1 that would maintain constant draft throu gh critical period; constant draft of 22 s econd-feet maintained, other drafts only as required by reser\-oir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet control water passing Azusa during flood season at rates less than Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Wasio over spillway in acre-feet 1,900 second- feet in acre-feet 1921 Jan. 5,160 51,342 4,405 1,.3.52 Feb. 4,490 50,745 4.490 1 222 Mar. 15,400 49,523 7,288 l!352 April 6,070 56,283 6,070 1,309 204 May 15,700 54,770 6,835 1,3.52 281 June 8,980 62,002 7,920 1,309 354 July 3,830 61,399 3,830 1,3.52 184 413 Aug. 2,450 59,450 2,450 1,352 184 378 Sept. 1,840 57,536 1,840 1,309 238 286 Oct. 2,040 55,703 2,040 1,352 214 Nov. 1,800 54,137 1,800 1,309 139 Dec. 119,000 52,689 5,045 39,506 1,352 Total or average 186,760 54,013 39,506 15,922 606 2.269 1922 Jan. 62,100 125,786 9,344 107,332 1,352 Feb. 88,900 69,858 8,440 83,316 1.222 Mar. 47,800 65,780 9,344 2,882 1,.352 April 31.400 100,002 9,042 1,309 5.65? 311 May 24,700 115,088 9,344 l,3.i2 10,327 446 June 14,400 118,319 9,042 1,30<.) 13,742 522 July 0,100 108.104 8,.576 1,352 15,922 565 Aug. 5,080 90,789 5,080 1,3.52 16,106 464 Sept. 3,290 72,867 3,290 1,309 15,527 307 Oct. 3,110 55,724 3,110 1,3.52 214 Nov. .5,310 54,158 4,519 1,.309 141 Dec. 21,500 53,499 8,456 1,990 1,352 Total or average 316.690 87,587 195,520 15,922 77.276 2.970 1923 Jan. 7,1.30 63,201 6.968 12.058 1.352 Feb. 7,830 49,955 7.791 1.222 Mar. 7,320 48,772 7.320 1.352 April May 8,3.30 47,420 8.079 1,309 182 5,480 46,180 5,480 1,352 244 June 3,700 44,584 3.700 1,309 288 July 2.420 42,987 2,420 1,352 331 Aug. 1,990 41, .304 1,990 1,352 299 Sept. 1,750 39,653 1,750 1,309 232 Oct. 1.710 38.112 1.710 1,352 171 Nov. 1,960 36,589 1,960 1.309 111 Dec. 2.130 35.169 2,130 1.352 Total or average 51,7.50 51.298 12,056 1.5,922 1,858 THE CONTROL OF FLOODS BY RESERVOIRS. 421 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a lev jlthat would maintain constant draft through critical period; cons tant draft of 18 second-feet maintained, other drafts only as required by ■eservoir operating diagram Flood control Year and Stage of reservoir at _ begimiing of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1,900 second- feet in acre-feet 1921 44,192 4,405 1,107 Jan. 43,840 4,490 999 Feb. 42,841 7.288 899 1.107 Mar. 48,947 6.070 1.071 186 April 47,690 6.835 1,107 250 May 55,198 7.920 1.071 329 June 51,858 3,830 1,107 61 385 July 53,305 2.450 1,107 61 353 Aug. 51,784 1,840 1,071 119 270 Sept. 50,324 2.040 1,107 111 204 Oct. 48,902 1.800 1,071 131 Nov. 47,700 5.045 45,446 1,107 Dec. Total or average 54.013 46,345 13,032 352 2,108 1922 115.102 9.344 107,317 1,107 Jan. 59.434 8,440 86.263 999 Feb. 52.632 9..344 40.859 1,107 Mar. 49,122 9,042 13,915 1.071 192 April 56,302 9,344 1.107 297 May 70,254 9.042 1,071 2.856 385 June 71,300 8,576 1,107 4,365 444 July 65.908 5,080 1,107 4.549 393 Aug. 59.859 3,290 1,071 4,402 282 Sept. 54.104 3,110 1.107 3.801 202 Oct. 48,994 4,519 260 1.071 133 Nov. 48,321 8,456 11.295 1.107 - Dec. Total or average 87,587 259,909 13,032 19,973 2.328 1923 48.963 6.968 1,107 Jan. 48.018 7.791 999 Feb. 47,058 7.320 1,107 Mar. 45,951 8.079 1,071 178 April 44,953 5.480 1,107 240 May 43,606 3.700 1,071 284 June 42,251 2.420 1,107 329 July 40,815 1.990 1,107 299 Aug. 39,409 1.7,50 1,071 236 Sept. 38,102 1,710 1.107 173 Oct. 36,822 1,960 1,071 111 Nov. 35,640 2.130 1.107 Dec. Total or 51,298 13.032 1,850 average 422 WATER RESOURCES OF CALIFORNIA. TABLE 15a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Compute (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Flood control by reservoir operating diagram Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, other drafts only as required by eservoir operating diagram Flood Year and month Run-off at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in aore-fect control water passing Azusa during flood season at rates less than l.gOOsecond- feet in acre-feet Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet 1924 Jan. 2,170 33,817 2,170 n 1,352 Feb. 1,790 32,465 1,790 (1 1,265 Mar. 4,130 31,200 3,714 1,352 April 0,190 30,264 6,190 1,309 141 May 3,650 28,814 3,650 1,352 186 June 1,660 27,276 1,660 1,309 214 July 1,000 25,753 1,000 1,352 248 Aug. 756 24,153 756 1,352 222 Sept. 744 22,579 744 1,309 167 Oct. 873 21,103 873 1,352 123 Nov. 1,190 19,628 1,190 1,.309 79 Dec. Total or 1,780 18,240 1,780 1,352 average 25,933 25,517 15,965 1,380 1925 Jan. 1,710 16,888 1,710 1,352 Feb. 1,620 15,536 1,620 1,222 Mar. 2,510 14,314 2,423 1,352 April 7,200 13,049 5,765 n 1,309 89 May 3,050 13,086 3,050 1,352 105 J.ine 1,840 11,629 1,840 1,309 131 July 824 10,189 824 , 1,352 141 Aug. 621 8,696 621 1,3.52 117 .Sept. 492 7,227 492 1,309 81 (let. 873 5,837 873 1.352 52 Nov. 1,010 4,433 1,010 1,309 28 Dec. Total or average 1,050 3,096 1,650 1,352 23,400 21.878 15,922 744 1926 Jan. 1,540 1,744 1,540 1,352 I'cb. 7,lt40 392 5,485 1,222 Mar. 3,650 1,625 3,650 1.352 April 69,000 273 8,233 1,309 159 May 13,000 59,572 9,142 I) 1,352 293 June 5,500 61,785 5,500 1,309 349 July 3,120 60,127 3,120 1,352 408 Aug. 2,070 58,367 2,070 1.352 373 Sept. 1,580 56,642 1,580 1,309 284 Oct. 55.049 Nov. Dfc. Total or average 107.400 40.320 11.909 1,866 THE CONTROL OF FLOODS BY RESERVOIRS. 423 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feef) in reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control Year and Stage of reservoir at _ beginning of month in acre-feet water Constant month Passed ty dam for prior rights in acre-feet passing Azusa during flood season at rates less than draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre- feet Evaporation from reservoir surface in acre-feet Waste over spillway in aore-feet 1,900 second- feet in acre-feet 1924 34,533 2,170 1,107 Jan. 33,426 1,790 1,035 Feb. 32,391 3,714 1,107 Mar. 31,700 6,190 1,071 147 April 30.482 3,650 1,107 192 May 29,183 1,660 1,071 224 June 27,888 1,000 1,107 260 July 26,521 756 1,107 236 Aug. 25,178 744 1,071 178 Sept. 23,929 873 1,107 131 Oct. 22,691 1,190 1,071 85 Nov. 21,535 1,780 1,107 Dec. Total or average 25,517 13,068 1,453 1925 20,428 1,710 1,107 Jan. 19,321 1,620 999 Feb. 18,322 2,423 1,107 Mar. 17,302 5,765 1,071 105 April 17,561 3,050 1,107 141 May 16,313 1,840 1,071 163 June 15,079 824 1,107 184 July 13,788 621 1,107 163 Aug. 12,518 492 1,071 117 Sept. 11,330 873 1,107 85 Oct. 10,138 1,010 1,071 52 Nov. 9,015 1,650 1,107 Dec. Total or average 21,878 13.032 1,010 1926 7,908 1,540 1,107 Jan. 6,801 5,485 999 Feb. 8,257 3,650 1,107 Mar. 7,150 8,233 11,836 1,071 165 April 54,845 9,142 1,107 276 May 57,320 5,500 1,071 238 319 June 55,692 3,120 1,107 246 387 July 53,952 2,070 1,107 307 355 Aug. 52,183 1,580 1,071 297 270 Sept. 50,545 Oct. Nov. Dec. Total or average 40,320 11,836 9,747 1,088 1.772 424 WATER RESOURCES OP CALIFORNIA. TABLE 15a (Concluded). SAN GABRIEL COMPARISON OF WATER YIELD FOR COORDINATED WITH SEASONAL Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second-feet passed for prior rights. Run-off at Azusa in acre-feet Flood control by reservoir operating diagram Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reservoir operating diagram Year and month Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over- year storage (22 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet Total for period, Jan.1, 1897, to Oct.1, 1926 Average for period, Jan.1, 1897, to Oct.1, 1926 3,731,977 125.445 1,513,303 50,867 "1,010,662 "33.972 473,905 15,930 676,322 22,734 65,386 2,198 " These figures contain 7601 aore-feet total or an average of 256 acre-feet per season of water contributed from outside t lie exact period of analysis. In the computations from which this table is prepared, the wafer in storage on October 1, 1926, the end of the psriod, is less by this amount than on January I. 1897, the beginning of the period. Since in the computations tliis water wis released as fljod cjntrol water during the first flood season of the period, the exact yield of flood control water for the period is less than here shown by this amount. THE CONTROL OP FLOODS BY RESERVOIRS. 425 RESERVOIR ON SAN GABRIEL RIVER. TWO METHODS OF FLOOD CONTROL AND OVER- YEAR STORAGE, tions Carried out on a Daily Basis. mary, see Table 15, page 180.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. Reservoir emptied of seasonal storage each year. Flood control, holding maximum reservoir space required (131,000 acre-feet) in reserve throughout flood season Reservoir emptied each summer to a level that would maintain constant draft through cr period; constant draft of 18 second-feet maintained, other drafts only as required by reservoir operating diagram tical Stage of reservoir at begirming of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over- year storage (18 second- feet) in acre-feet Seasonally stored water in acre-feet Evaporation from I'eservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1,513,303 50,867 1,685,053 56,641 387,891 13,039 87,773 ''2,950 56,534 1,900 Total for period, Jan. 1, 1897, to Oct. 1, 1926 Average for period, Jan.1. 1897, to Oct.1, 1926 ^ In the computations for this table, the period of analysis closed with 1423 acre-feet more water in storage than at the beginning, the equivalent of 48 acre-feet per season. Since in the computations this water was stored in the last year of the period of analysis, the exact yield in seasonally stored water for the period is larger than here shown by this amount 2T— 52411 426 WATER RESOURCES OF CALIFORNIA. TABLE 16a. SAN GABRIEL RESER COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control .irtlally Water drawn from reservoir or ly as require dby Constant draft o r 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control at vpater water month Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet passmg Azusa during flood season at rates less than 1.900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet passmg Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1897 Jan. 3,617 62,650 3,017 13,131 62,650 3,617 11,779 Feb. 10,148 49,519 7,262 5,432 49,519 7,262 4,628 Mar. 28,623 55,971 9,344 55,553 9,344 April 17.519 75,250 9,042 238 73,480 9,042 May 8,8.51 83,489 8,126 369 80,413 8,126 June 4,033 83,845 4,033 426 79,433 4.033 July 2,343 83,419 2,343 504 77,712 2,343 Aug. 1,613 82,915 1,613 466 75,875 1,613 Sept. 1,226 82,449 1,226 359 74,083 1,226 Oct. 5,564 82,090 2,622 280 72,437 2,622 Nov. 1,860 84,752 1,860 188 73,769 1.860 Dec. 1,875 84.564 1,875 11,646 72,289 1,875 Total or average 96,270 52,963 30,209 2,830 52,963 16.407 1898 Jan. 2,453 72.918 2,453 13,484 70,937 2,453 10,849 Feb. 2,241 .59,434 2,241 58,736 2,241 Mar. 2,131 59,434 2,131 57,514 2,131 April 1,9.50 59,434 1.9.50 210 56,162 1,950 May 2,213 59,224 2,213 286 54,651 2.213 June 1,1.59 58,938 1,159 343 53.029 1,159 July 672 58,595 672 403 51.395 672 Aug. 456 58,192 456 375 49,674 456 Sept. 467 57,817 467 289 47,985 467 Oct. 533 57.528 5.33 222 46,420 533 Nov. 580 57.306 580 145 44,876 580 Dec. Total or average 832 57.161 832 43,442 832 15.687 15,687 13,484 2,273 15,687 10,849 1899 Jan. 1,414 57,161 1,414 42,090 1,414 Feb. 1,244 57,161 1,244 40.738 1,244 Mar. 1,023 57,161 1,623 39.516 1,623 April 1,262 57,161 1,262 206 38.164 1,262 May 842 56,955 842 280 36.694 842 June 565 56.675 565 333 35,128 565 July 221 56..342 221 393 33,571 221 Aug. 295 55,949 295 366 31.931 295 Sept. 220 55,583 220 28 1 30,319 220 Oct. 683 55,299 683 214 28,812 683 Nov. 847 55,085 847 143 27,313 847 Dec. Total or average 1,247 54,942 1.247 25.913 1,247 10.463 10,463 2,219 ' 10,463 THE CONTROL OF FLOODS BY RESERVOIRS. 427 VOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. Flood control completely coordinated with conservation coordinated with conservation Reservoir emptied each summer to a level that would maintain constant feet maintained,_ othe_ r drafts draft through critical period: constant draft of 22 second-feet reservoir operating diagram maintained, othe r drafts only as requir ed by reservoir operating diagram Flood control Constant draft from over-year storage (22 second- feet) in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 spcond- feet in acre-feet Constant draft from over-year storage (22 second- feet) in acre-feet Variable summer draft from seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre feet Waste over spillway in acre-feet Year and month 1897 1,352 62,650 3,617 11,779 1,352 Jan. 1,222 49,519 7,262 4,628 1,222 Feb. 1,352 55,553 9,344 1,352 Mar. 1,309 235 73,480 9,042 1,309 1,249 234 April 1,352 353 79,165 8,126 1,352 3,012 343 May 1,309 412 75,183 4,033 1,309 3,093 396 June 1,352 485 70,385 2,343 1,352 3,197 447 July 1,352 440 65,389 1,613 1,352 3,197 393 Aug. 1,309 337 60,447 1,226 1,309 3,153 290 Sept. 1,352 258 55,695 2,622 1,352 220 Oct. 1,309 171 57,005 1,860 1,309 143 Nov. 1,352 55,613 1,875 1,352 Dec. Total or average 15,922 2,691 52,963 16,407 15,922 16,901 2,466 1898 1,352 54,261 2,453 1,352 Jan. 1,222 52,909 2,241 1 222 Feb. 1,352 51,687 2,131 i;352 Mar. 1,309 202 50,335 1,950 1,309 n 190 April 1.352 270 48,836 2,213 1,352 252 May 1,309 325 47,232 1,159 1,309 296 June 1,352 369 45,627 672 1,352 .343 July 1,352 337 43,932 456 1,352 313 Aug. 1,309 25G 42,267 467 1,309 238 Sept. 1,352 192 40,720 533 1,352 179 Oct. 1,309 125 39,189 580 1,309 115 Nov. 1,352 37,765 832 1,352 Dec. Total or average 15,922 2,076 15,687 15,922 1,926 1899 1,352 36,413 1,414 1,352 n Jan. 1,222 35,061 1,244 1,222 Feb. 1,352 33,839 1,623 1,352 Mar. 1,309 161 32,487 1,262 1.309 149 A|>ril 1,352 214 31,029 842 1,352 194 May 1,309 248 29,483 565 1,309 224 June 1,352 288 27,950 221 1,3,52 260 July 1,352 260 26,338 295 1,352 234 Aug. 1,309 198 21,752 220 1309 175 Sept. 1,352 147 23,268 683 r352 129 Oct. 1,309 91 21,787 847 1,309 83 Nov. 1,352 20,395 1,247 1,352 Dec. Total or average 15,922 1,607 10,463 15,922 1,448 428 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Water drawn froir reservoir only as required by Constant draft of 22 second- reservoir operating diagram only as required by Flood Flood Runoff control control Year and month at Azusa in acre feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1 ,900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1900 Jan. 1,968 54,942 1.968 24,561 1.968 Feb. 1,111 54,942 1,111 23,209 1,111 Mar. 1,230 54,942 1,230 21.987 1,230 April 1,012 54,942 1,012 200 20.635 1,012 May 2,275 54,742 2.275 272 19.211 2.275 June 893 54,470 893 327 17.712 893 July 309 .54,143 369 385 16,223 369 Aug. 246 63,758 246 357 14.679 246 Sept. 238 53,401 238 276 13,158 238 Oct. 307 53.125 307 210 11.728 307 Nov. 11,068 52.915 1.058 139 10,281 1,058 Dec. 1,269 62.786 1,269 18,923 1,269 Total or average 21,986 11,976 2,160 11,976 1901 Jan. 10,391 62.786 6,661 16,586 17,571 6,661 Feb. 38,709 49.930 8,350 19.884 19,949 8,350 Mar. 13,.'589 60,405 9,138 49,086 9.138 April 6,.515 64,856 6,545 224 52,185 6,.545 May 7,410 64.632 6,990 301 50.684 6.990 June 3,749 64,781 3,749 363 49.522 3,749 July 1.845 64,418 1,845 426 47.908 1,845 Aug. 1,240 63,992 1,240 397 46,203 1.240 Sept. 1,012 63,595 1,012 305 44,530 1,012 Oct. 1,476 63,290 1,476 2.34 42,975 1,476 Nov. 1,904 63,056 1.904 155 41,439 1,904 Dec. Total or average 1,660 62,901 1,660 40,015 1,660 89,560 50.570 36,470 2,405 50,570 1902 Jan. 1,722 62,901 1,722 38,663 1,722 Feb. 2,055 62,901 2,055 37.311 2.055 Mar. 6,088 62,901 5.590 36.089 5.590 April 3,928 63,399 3.928 218 35,235 3.928 May 2.398 63.181 2.398 295 33.773 2,398 June 1,190 62.886 1.190 355 32.217 1.190 July 676 62,.')31 676 420 30,672 676 Aug. 430 62,111 430 389 2!),048 430 Sept. 298 61,722 298 301 27.4.50 298 Oct. 430 61.421 430 228 25.955 430 Nov. 1,131 61.193 1.131 151 24.464 1.131 Dec. Total or average 1,968 61.042 1,968 23.068 1,968 22,314 21,816 2,357 21,816 THE CONTROL OF FLOODS BY RESERVOIRS. 429 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. Flood control completely coordinated with conservation coordinated with conservation Reservoir emptied each summer to a level that would maintain constant feet maintained, other drafts 6n ft through critical period; constant draft of 22 second-feet reservoir operating diagram maintained, othe r drafts only as required by reservoir operating diagram Flood control Cons tant draft from over-year storage (22 second- feet) in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at _ beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (22 second- feet) in acre-feet Variable summer draft from seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1900 1.352 19,043 1,968 1,352 Jan. 1,222 17,691 1,111 1,222 Feb. 1,352 16,469 1,230 1,352 Mar. 1,309 115 15,117 1,012 1,309 95 April 1,352 147 13,713 2,275 1,352 121 May 1,309 180 12,240 893 1,309 135 June 1,352 192 10,796 369 1,352 149 July 1,352 169 9,295 246 1,352 123 Aug. 1,309 121 7,820 238 1,309 85 Sept. 1,352 95 6,426 307 1,352 56 Oct. 1,309 59 5,018 1,058 1,.309 32 Nov. 1,352 13,687 1,269 1,352 Dec. Total or average 15,922 1,078 11,976 15,922 796 1901 1,352 12,.335 6.661 1,.352 Jan. 1,222 14,713 8,350 1,222 Feb. 1,352 43,850 9,138 1,352 Ma-. 1,309 192 46,P49 6,545 1,309 181 April 1,352 260 45,459 6,990 1,.352 240 May 1,309 305 44,317 3,749 1,309 286 June 1,352 353 42,722 1,845 1,352 329 July 1,352 321 41,041 1,240 1,35? 300 Aug. 1,309 246 39,389 1,012 1,309 230 Sept. 1,352 184 37,850 1,476 1,352 171 Oct. 1,309 115 36,327 1,904 1.309 109 Nov. 1,352 34,909 1,660 1,352 Dec. Total or average 15,922 1,976 50.570 15,922 1.846 1902 1,352 33,557 1,722 1,352 Jan. 1,222 32.205 2,055 1,222 Feb. 1,352 30.983 5,590 1,352 Mar. 1,309 153 30, '29 3,928 1,309 141 April 1,352 204 28,679 2,398 1.352 184 May 1,309 236 27,143 1,190 1.309 214 June 1,352 272 25,620 676 1,352 246 July 1352 246 24,022 4.30 1,352 222 Aug. 1,309 186 22,448 298 1,309 167 Sept. 1,352 139 20,972 430 1,352 123 Oct. 1,.309 87 19,497 1,131 1,309 77 Nov. 1,352 18,111 1,968 1,352 Dec. Total or average 15,922 1,523 21,816 15.922 1,374 430 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Water drawn from reser\'oir only as required by Constant draft c f 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and month at Azusa in acre-feet Stage of reservoir at_ beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet E\-apora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of resen'oir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1903 Jan. 9,100 61,042 2,536 12,128 21,716 2,536 Feb. 5,665 55,478 5,497 5,959 26,928 5,497 Mar. 15,802 49,687 7,898 25,874 7,898 April 47,127 57,591 9,042 260 32,426 9,042 May 13,343 95,416 9,116 369 68,994 9,116 June 5,653 99,274 5,653 476 Tl,.546 5,653 July 2,644 98,798 2.644 561 69.852 2,644 Aug. 1,783 98,237 1,783 522 68,054 1,783 Sept. 1,488 97,715 1,488 403 66,292 1,488 Oct. 1,476 97,312 1,476 305 64,670 1,476 Nov. 1,428 97,007 1,428 204 63,082 1,428 Dec. Total or average 1,476 96,803 1,476 61,618 1.476 106,985 50,037 18,087 3,100 50,037 1904 Jan. 1,500 96,803 1,500 60,260 1,500 Feb. 2,744 96,803 2,177 58,914 2,177 Mar. 6,813 97,370 4,724 58,216 4,724 April 5,337 99,459 5,337 295 58,953 5,337 May 4,089 99,164 4,089 397 57,436 4,089 0" June 1,517 98,767 1,517 476 55,804 1,517 July 861 98,291 861 559 51,166 861 Aug. 793 97,732 793 520 52,431 793 Sept. 643 97.212 613 401 50,730 643 Oct. 738 96,811 738 305 49,155 738 Nov. 762 96,.506 762 204 47,597 762 Dec. Total or average 1,039 96,302 1,039 46,155 1,039 26,836 24.180 3,157 24,180 1905 Jan. 2,251 96,302 2,251 17.237 44,803 2,251 Feb. 25,880 79,065 8,206 41,863 43,461 8,206 6,204 Mar. 75,140 54,876 9,281 18,198 53,099 9,281 16,231 April 19,580 102,537 9,042 313 101.975 9,042 May 17,090 112,702 9,344 446 110,893 9,344 June 8,271 120.062 7.960 543 116,849 7,960 July 5,103 119,830 5,103 639 115,322 5,103 Aug. 2,631 119.191 2.631 593 113,349 2,631 Sept. 1,869 118,598 1,869 456 111,426 1,869 Oct. 1,770 118,142 1,770 347 109,681 1,770 Nov. 2,660 1 17,795 2,660 14.595 232 108,000 2,660 3,610 Dec. Total or average 2,470 102,908 2,470 7.444 102,861 2,470 6,944 164,715 62,587 99,337 3,569 62,587 32,989 THE CONTROL OF FLOODS BY RESERVOIRS. 431 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azvisa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Flood control completely coordinated with conservation coordinated with conservation Reservoir emptied each summer to a level that would maintain constant | feet maintained, other drafts dra 't through critical period; constant draft of 22 second-feet resen-oir operating diagram maintained other drafts only as required by reservoir operating diagram Flood control Constant draft Evapora- Stage of water passing Azusa during Constant draft Variable summer Evapora- tion from Year and month from tion from Waste reservoir Passed from draft Waste over-year reservoir over at by dam flood over-year from reserv'oir over storage (22 second- surface in acre-feet spillway in acre-feet beginning of month in for prior rights in acre-feet season at rates less storage (22 second- seasonally stored water in surface in acre-feet spillway in acre-feet feet) in acre-feet acre-feet than 1,900 second- feet in acre-feet feet) in acre-feet acre-feet 1903 1,352 16,759 2,.536 1,352 Jan. 1,222 21,971 5,497 1,222 Feb. 1,352 20,917 7,898 1,352 Mar. 1,309 208 27,469 9,042 1,309 180 April 1,352 323 64,065 9,116 1,352 307 May 1,309 385 66,633 5,6.53 1,309 1,012 365 June 1,352 446 63,947 2,644 l,c52 1,107 421 July 1,352 410 61,067 1,783 1,352 1,045 379 Aug. 1,309 313 58,291 1,488 1,309 1,071 288 Sept. 1,352 236 55,623 1,476 1,352 214 Oct. 1,309 155 54,057 1,428 1,309 139 Nov 1,352 52,609 1,476 1,.352 Dec. Total or 15,922 2,476 50,037 15,922 4,235 2,293 average 1904 1,352 51,257 1,£00 1,352 Jan. 1,265 49,905 2,177 1,265 Feb. 1,352 49,207 4,724 1,352 Mar. 1,309 208 49,944 5,337 1,309 188 April 1,352 280 48,447 4,089 1,352 250 May 1,309 329 46 845 1,517 1,309 2)6 June 1,352 383 45,240 861 1,.352 343 July 1,352 349 43,545 793 1,352 313 Aug. 1.309 266 41,880 643 1,309 238 Sept. 1,352 206 40,3.33 738 1,.352 179 Oct. 1,309 133 38,802 762 1,309 115 Nov. 1,352 37,378 1,039 1,352 Dec. Total or 15,965 2,154 24,180 15,965 ),922 average 1905 1.352 36,026 2,251 1,352 Jan. 1,222 34,674 8,206 1,222 Feb. 1,352 51.126 9,281 13.658 1,352 Mar. 1,309 311 101,975 9,042 1,309 5,949 303 April 1,352 438 104,952 9,344 1,352 8,237 411 May 1,309 529 102,608 7,960 1,309 9,875 470 June 1.352 621 91,355 5.103 1,352 10,266 512 July 1,352 571 79,225 2,631 1,352 10,266 432 Aug. 1,309 436 67,175 1,869 1,309 9,935 300 Sept. 1,3,52 329 55,631 1,770 1,352 214 Oct. 1,309 220 54.065 2.660 1,309 139 Nov. 1,352 52.617 2,470 1,352 0] Dec. Total or 15,922 3,455 62,587 13.658 15,922 54,528 2,781 average 432 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For correspxjnding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Wate r drawn from reservoir oi ly as required by Constant draft o f 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and month at water water Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than 1,900 Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre feet Passed by dam for prior rights in acre-feet passing Azusa daring flood season at rates less than 1,900 second- second- feet in feet in acre-feet acre-feet 1906 Jan. 4,240 95,524 3,633 35,700 94,565 3,633 33,608 Feb. 3,060 60,425 3,960 60,212 3,960 Mar. 129,000 60,425 7,561 33,037 58,990 7,561 30,250 April 34,600 148,827 9,042 20,997 383 148,827 9,042 20,735 May 21,000 153,005 9,344 543 151,960 9,.344 June 15,500 164,118 9,042 682 161,723 9.042 July 9,350 169,894 8,664 811 166,198 8,664 Aug. 4,490 169.769 4,490 756 164,729 4,490 Sept. 2,840 169.013 2,840 583 162,639 2,840 Oct. 2,4.i0 168,430 2,450 444 160,763 2,450 Nov. 2,400 167,986 2,400 14,928 295 158,981 2,400 5,941 Dec. Total or average 11,600 152,763 4,030 97,132 151.445 4,030 94,462 241,430 67,456 201.800 4.497 67,456 184,996 1907 Jan. 58,400 03,201 9,217 57,512 63.201 9,217 56,159 I'ch. 47,100 54,872 8,439 31,125 54,873 8,439 29.904 Mar. 116,000 62,408 9,344 47,166 62,408 9,344 45.814 April 58,400 121,898 9,042 528 393 121,898 9,042 453 May 21,500 170,335 9,344 591 • 1,900 169,103 9,344 June 15,100 180,000 9,042 720 5,338 179,322 9,042 July 8,360 180,000 7,920 849 188 180,000 7.920 Aug. 5,390 179,403 5,390 787 178,241 5.390 Sept. 3,580 178,616 3,580 607 176,108 3.580 Oct. 4,090 178,009 4,090 8,257 460 174,200 4,090 3.106 Nov. 3,800 169,292 3,800 54,872 256 169,292 3,800 53,565 Dec. Total or average 3,600 114,164 3,600 12,600 114,164 3,600 12,164 345,320 82,808 212,060 4,663 7,426 82,808 201.165 1908 Jan. 11,100 101,564 4,973 2 4. .579 100,648 4,973 24.273 Feb. 15,000 83,112 8,741 37,743 81,150 8,741 35,256 Mar. 12,700 51,628 9,255 50,888 9,2.55 April May 9,280 ,55,073 8,056 202 52.i;81 8,656 7,190 55,495 7.139 337 52,100 7,139 June 4,190 55.209 4.190 329 50,537 4,190 July 2,560 54,880 2,560 387 48,919 2,560 Aug 2,210 54,493 2.210 .361 47,208 2,210 Sept. 1.820 54,132 1,820 278 45,531 1,820 Oct. 2,070 53,854 2,070 212 43.970 2,070 Nov. 1,960 53,642 1,960 J 39 42,432 1,960 Doc. Total or average 2.870 53,503 2.870 41,000 2,870 72.950 56,444 62,322 2,245 56,4-14 59.529 THE CONTROL OF FLOODS BY RESERVOIRS. RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) 433 Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. 1 "lood control completely coordinated with conservation coordinated with conservation 1 Reservoi >■ emptied each summe I- to a level that would mamtain onstant feet maintained, other drafts | dra Ft through critical peri od; constant draft of 22 second-feet reservoir operating dia gram maintained, other drafts only as required by reservoir operating diagram Flood control Constant draft from Evapora- tion from Waste Stage of reservoir Passed water passing Azusa during Constant draft from Variable summer draft Evapora- tion from Waste Year and month over-year storage - (22 second- feet) in acre-feet reseri-oir surface in acre-feet over spillway in acre-feet at beginning of month in acre-feet by dam for prior rights in acre-feet flood season at rates less than 1,900 second- feet in acre-feet over-yetr storage (•22 second- feet) in acre-feet from seasonally stored water in acre feet reservoir surface in acre-feet over spillway in acre-feet • 1906 1,352 51,265 3,633 1,352 Jan. 1,222 50,520 3,960 1,222 Feb. 1,352 49,298 7,561 23,965 1,352 Mar. 1,.309 381 145,420 9,042 15,432 1,309 13,028 357 April 1,352 541 140.852 9,344 1,352 15,553 498 May 1,309 674 135,105 9,042 1,309 17,843 569 June 1,352 803 121,842 8,664 1,.352 20.527 609 July 1,352 738 100,040 4,490 1,352 20,774 488 .A.ug. 1,309 567 77,426 2,840 1,309 20,043 315 Sept 1,352 430 55,759 2,450 1,352 ' 214 Oct. 1,309 286 54,193 2,400 1,309 139 Nov. 1,352 52,745 4,030 1,352 Dec. Total or average 15,922 4,420 67,456 39,397 15,922 107,768 3,189 1907 1,352 58,963 9,217 51,921 1,-352 Jan. 1,222 54,873 8,439 29,904 1,222 Feb. 1,.352 62,408 9,344 45,814 1,3.52 Mar. 1.309 391 121,898 9,042 1,309 9,221 375 April 1,352 585 160,351 9,344 1,352 19,487 539 May 1,309 720 3,351 151,129 9,042 1,309 21,773 609 June 1,352 847 133,496 7,920 1,352 24,466 642 July 1,352 781 107,476 5,390 1,352 24.651 462 Aug. 1,309 599 81,011 3,580 1.309 23,737 321 Sept. 1,352 450 55,644 4,090 1,.352 214 Oct. 1,309 254 54,078 3,800 1,309 139 Nov. 1,352 52,630 3,600 1,352 Dec. Total or 15,922 4,627 3,351 82,808 127,639 15.922 123,335 3,301 average 1908 1,352 51,278 4.973 5,543 1,352 Jan. 1,265 50,510 8,741 4,616 1.265 Feb. 1,352 50,888 9,255 1,352 Mar. 1,309 196 52,981 8,656 1,309 196 April 1,352 262 52,100 7,139 1,352 202 May 1,309 309 50,537 4,190 1,309 309 Jane 1,352 359 48,919 2,560 1,352 359 July 1,352 325 47,208 2,?10 1,352 325 Ajg. 1.309 252 45,531 1,820 1,309 252 Sept. 1,352 186 43,970 2,070 1,352 186 Oct. 1,309 123 42,432 ).960 1,309 123 Nov. 1,352 41,000 2,870 1,352 D-'c. Total or average 15,965 2,012 56,4441 10,159 15,965J 2,012 434 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control part'ally Water drawn from reservoir only as required by Constant draft c f 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and month at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing AiUBa daring flood season at rates less than 1,900 Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during - flood season at rates less than 1.900 « second- feet in acre-feet second- feet in acre-feet 1909 .Jan. 2.i,500 53,503 5.596 23,888 39.648 5,596 8.681 Feb. 59,400 49.519 8,440 42,858 49.519 8,440 41.897 Mar. 26,.300 57.621 9.344 57.360 9.344 April 28,000 74,577 9,042 268 72,964 9.042 May 15,200 93.267 9,344 391 90,351 9..344 June 8,570 98,732 8,319 476 94,474 8.319 July 5.040 98.507 5,040 559 92,956 5.040 Aug. 3,120 97.948 3.120 520 91,067 3.120 Sept. 2,320 97.428 2.320 401 89,221 2.320 Oct. 2,310 97.027 2.310 305 87,535 2.310 Nov. 2,880 96,722 2.880 204 85,897 2,880 Dec. Total or average 20,900 96,518 6.346 38.233 84,400 6.346 24.763 199,540 72.101 104.979 3,124 72.101 75.341 1910 Jan. 69,500 72,839 9.344 82.868 72,839 9.344 81.516 Feb. 11,500 50,127 8,435 2,689 50,127 8,435 2,292 Mar. 9,590 50,503 9.029 49,678 9,029 April 8,270 51,0f)4 8,120 190 48,887 8.120 May 5,050 51,024 5.050 262 47,542 5,050 June 3,560 50,702 3.560 311 45,940 3,560 July 2,450 50.451 2.450 369 44,340 2,450 Aug. 1,710 50.082 1.710 341 42.651 1,710 Sept. 1,370 49.741 1.370 264 40.992 1,370 Oct. 1,560 49.477 1.560 202 39.449 1,560 Nov. 1,870 49.275 1.870 133 37,923 1.870 Dec. Total or average 2,020 49.142 2.020 36,501 2.020 118,450 54.518 85.557 2.072 54.518 83.808 1911 Jan. 37,200 49,142 6.441 7,031 35.149 6,441 6.949 Feb. 44.300 72.870 8.440 .54,016 57.607 8.440 38.010 Mar. 122,000 54.714 9.344 57,434 54.235 9,344 55.857 April May 28.200 109,936 9.042 335 109.682 9.042 16.600 128.759 9,344 482 127.196 9.344 June 7.500 135.,533 7,,322 589 132.622 7.322 July 5.230 135.122 5,230 696 130.912 5.230 Aug. 3.610 134,426 3,610 644 128.884 3.610 Sept. 2.830 133,782 2,830 498 126.909 2.830 Oct. 3.140 133.284 3,140 379 12.5,124 3.140 Nov. 2.800 132.905 2,800 11.766 248 123.411 2.800 1.061 Dec. Total or average 2.870 120,891 2,870 2.3.312 120,803 2.870 22,352 276.280 70,413 153.559 3,871 70.413 124,229 THE CONTROL OP FLOODS BY RESERVOIRS, 435 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. 'lood control completely coordinated with conservation coordinated with conservation Reservoir emptied each summer to a level that would mamtam constant feet maintained, other drafts draft through ritical period; constant draft of 2 2 second-feet reservoir operating diagram maintained, other drafts only as required by reservoir operating diagram Flood control Constant draft from over-year storage (22 second- feet) in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (22 second- feet) in acre-feet Variable summer draft from seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1909 1,352 39,648 5,596 8,681 1,352 Jan. 1,222 49,519 8,440 41,897 1,222 Feb. 1,352 57,360 9,344 1,353 Mar. 1,309 262 72,964 9,042 1,309 1,190 258 April 1,352 381 89,165 9,344 1,352 5,041 369 May 1,309 460 88,259 8,319 1,309 6,306 428 June 1,352 537 80,467 5,040 1,352 6,639 478 July 1,352 494 71,998 3,120 1,352 6,578 412 Aug. 1,309 377 63,656 2,320 1,309 6,365 295 Sept. 1,352 286 55,687 2,310 1,352 214 Oct. 1,309 188 54,121 2.R80 1,309 139 Nov. 1,352 52,673 6,346 1,682 1,352 Dec. Total or average 15,922 2,985 72,101 52,260 15,922 32,119 2,593 1910 1,352 64,193 9,344 72,870 1,352 Jan. 1,222 50,127 8,435 2,292 1,222 Feb. 1,352 49,678 9,029 1,352 Mar. 1,309 186 48,887 8,120 1,309 186 April 1,352 250 47,542 5,050 1,352 250 May 1,309 291 45,940 3,.560 1,309 291 June 1,352 337 44,340 2,450 1,352 337 July 1,352 307 42,651 1,710 1,352 307 Aug. 1,309 234 40,992 1,370 1,309 234 Sept. 1,352 174 39,449 1,560 1,352 174 Oct. 1,309 113 37,923 1,870 1,309 113 Nov. 1,352 36,501 2,020 1,352 Dec. Total or 15,922 1,892 54,518 75,162 15,922 1,892 average 1911 1,352 35,149 6,441 6,949 1,352 Jan. 1,222 57,607 8,440 38,010 1,222 Feb. 1,352 54,235 9,344 55,857 1,3.52 Mar. 1,309 335 109,682 9,012 1,309 7,198 325 April 1,352 478 120,008 9,344 1,352 11,311 446 May 1,309 579 114,155 7,322 1,309 12,671 502 June 1,352 676 99,851 5,230 1,352 13.155 537 July 1,352 623 84,807 3,610 1,352 13,094 446 Aug. 1,309 476 69,915 2,830 1,309 12,612 306 Sept. 1,352 361 55,688 3,140 1,352 215 Oct. 1,309 238 ,'54,121 2,800 1,309 139 Nov. 1,352 52,673 2,870 1,.352 Dec. Total or 15,922 3,766 c 70,413 100,816 15,922 70,041 2,916 average 436 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Wate r drawn from reservoir oi ly as required by Constant draft o f 22 second- reservoir operating diagram only as reriuired by Flood Flood Run-off control control Year and month at Azusa in Stage of reservoir Passed water passing Azusa during flood season at rates less than 1,900 Evapora- tion from reservoir surface in acre-feet Waste Stage of reservoir Passed water passing Aztisa during flood season at rates less than 1,900 acre-feet at beginning of month in acre-feet by dam for prior rights in acre-feet over spillway in acre-feet at beginning of month in acre-feet by dam for prior rights in acre-feet second- second- feet in feet in acre-feet acre-feet 1912 Jan. 2,710 97,579 2,710 97,099 2,710 Feb. 2,230 97,579 2,230 95,747 2,230 Mar. 22,!»00 97,579 8,199 3,590 94,482 8,199 496 April 18,000 108,690 8,515 319 107,335 8,515 May 10,900 117,856 8,828 454 115,196 8.828 June 4,990 119,474 4,990 539 11.5,474 4,990 July ,3,060 118,935 3,060 637 113,040 3,060 Aug. 1,960 118,298 1,960 591 111,675 1,960 Sept. 1,5.50 117,707 1,550 454 109,7.58 1,5.50 Oct. 1,8.30 117,253 1,830 347 108,019 1,830 Nov. 1,7.30 116,906 1,730 232 106,340 1,730 Dec. Total or average 1,700 116,674 1,700 7.665 104,815 1,760 73,620 47,362 11,255 3,573 47,362 496 1913 Jan. 2,910 109,009 2,910 8,725 103,463 2,910 4,136 Feb. 13,200 100,284 4,753 27,773 97,975 4,753 24,767 Mar. 10,200 80,058 8,759 11,336 80,433 8,759 10,660 April 7,110 71,003 7,091 238 69,862 7,091 May 4,970 70,874 4,970 319 68,370 4,970 June 2,890 70,555 2,890 385 66,709 2,890 July 1,690 70,170 1,690 452 65,033 1,690 Aug. 1,070 69,718 1,070 418 63,255 1,070 Sept. 893 69,300 893 323 61,512 893 Oct. 910 68,977 910 246 59,906 910 Nov. 2,280 68,731 2,280 165 58,330 2,280 Dec. 2,170 68,566 2,170 56,874 2,170 Total or average 60,323 40,386 47,834 2.546 40,386 39.563 1914 Jan. 01,400 68,566 6,271 56,127 55,522 6,271 47,159 Feb. 121,000 67,568 8,440 64,933 62,140 8,440 58,284 Mar. 48,000 11.5,195 9,344 53,083 115,194 9,344 52,388 April Niay 21,400 100,768 9,042 307 100,110 9,042 16,900 112,819 9,344 430 110,854 9,344 June 9,580 119,945 8,585 535 116,630 8,,585 July 5,570 120,405 5,570 641 115,786 5,570 Aug. 3,630 119,704 3,630 595 113,803 3,630 Sept. 2,730 119,169 2,730 4.58 111,879 2,730 Oct. 2,770 118,711 2.770 349 110,134 2,770 Nov. 2,440 118,362 2,440 234 108,451 2,440 Dec. 4,290 118,128 4,290 53,539 106,922 4,290 40.981 Total or average 299,710 72,450 227,682 3,549 72,456 198,812 THE CONTROL OF FLOODS BY RESERVOIRS. 437 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. 1 -lood control completely coordinated with conservation 1 coordinated with conservation Reservoir emptied each summer to a level that would maintain constant | feet maintained, other drafts draft through :ritical period; constant draft of 22 second-feet reservoir operating dia ?ram maintained, other drafts only as required by reservoir operatmg diagram Flood control Constant draft from Evapora- tion from Waste Stage of reservoir Passed water passing Azusa during Constant draft from Variable summer draft Evapora- tion from Waste Year and month over-year storage (22 second- feet) in acre-feet reservoir surface in acre-feet over spillway in acre-feet at beginning of month in aere-feet by dam for prior rights in acre-feet flood season at rates less than 1,900 second- feet in acre-feet over-year storage (22 second- feet) in acre-feet from seasonally stored water in acre-feet reservoir surface in acre-feet over spillway in acre-feet 1912 1,352 51,321 2,710 1,352 Jan. 1,265 49,969 2,230 1,265 Feb. 1,352 48,704 8,199 1,352 Mar. 1,309 315 62,053 8,515 1,309 238 April 1,352 442 69,991 8,828 1,352 1,168 315 May 1,309 525 69,228 4,990 1,309 1,606 373 June 1,352 613 65,940 3,060 1,352 1,660 426 July 1,352 565 62,502 1,960 1,352 1,660 359 Aug. 1,309 430 69,131 1,550 1,309 1.667 291 Sept. 1,352 327 55,864 1,830 1,352 215 Oct. 1,309 216 54,297 1,730 1,309 139 Nov. 1,352 52,849 1,760 1,352 Dec. Total or 15,965 3,433 47,362 15,965 7,761 2,356 average 1913 1,352 51,497 2,910 1,352 Jan. 1,222 50,145 4,753 1,222 Feb. 1,352 57,370 8,759 1,352 Mar. 1,309 232 57,459 7,091 1,309 206 April 1,352 309 55,993 4,970 1,352 27'' May 1,309 367 54,367 2,890 1,309 321 June 1,352 426 52,737 1,690 1,352 375 July 1,352 391 51,010 1,070 1,352 340 Aug. 1,309 297 49,318 893 1,309 260 Sept. 1,352 224 47,749 910 1,352 196 Oct. 1,309 147 46,201 2,280 1,309 127 Nov. 1,352 44,765 2,170 1,352 Dec. Total or 15,922 2,393 40,386 15,922 2,099 average 1914 1,352 43,413 6,271 35,050 1.352 Jan. 1,222 62,140 8,440 58,284 1,222 Feb. 1,352 115,194 9,344 52,388 1,352 Mar. 1,309 305 109,110 9,042 1,309 5,652 301 April 1,352 428 105,206 9,344 1,352 8,299 410 May 1,309 530 102,701 8,585 1,309 9,875 472 June 1,352 631 92,040 5,570 1,352 10,512 516 July 1,352 572 79,660 3,630 1,352 10,450 432 Aug. 1,309 436 67,426 2,730 1,309 10,113 301 Sept. 1,352 331 55,703 2,770 1,352 214 Oct. 1,309 220 54,137 2,440 1,309 139 Nov. 1,352 52,689 4,290 1,352 Dec. Total or 15,922 3,453 72,456 145,722 15,922 54,901 2,785 average 438 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood con trol partially Water drawn from reservoir only as required by Constant draft c f 22 second- reser\'oir operating diagram only as required by Flood Flood Run-off control control Year and month at Azusa in Stage of water passing Azusa Evapora- Waste Stage of Passed water passing Azusa acre-feet r3S8rvoir at beginning of month in acre-feet Passed during tion from reser\-oir at beginning of month in acre-feet ty dam during by dam for prior flood season reservoir surface over spillway for prior rights in flood season rights in acre-feet at rates less than 1,900 in acre-feet acre-feet acre-feet at rates less than 1,900 second- second- feet in feet in acre-feet acre-feet 1915 Jan. 7,380 64,5S9 4,428 9,932 64.589 4,428 8,659 Feb. 30,200 57,609 8,412 21,485 57.530 8,412 20,577 Mar. 21,500 57,912 9,344 57,519 9.344 .\pril 17,300 70,068 9,042 238 68,323 9.042 May 20,400 78.088 9,344 369 75,034 9,344 June 11,400 88,775 8,967 476 84,395 8,967 Joly 7,010 90,732 7,010 529 85.085 7,010 Aug. 3,980 90,203 3,980 492 83,225 3,980 Sept. 3,270 89,711 3,270 381 81,409 3,270 Oct. 2,770 89,330 2,770 290 79,745 2,770 Nov. 3,010 89,040 3,010 3,o80 192 78,125 3,010 Dec. 3,580 88,848 76.640 3.580 Total or average 131,800 73,157 31,417 2,967 73.157 29,236 1916 Jan. 148,000 88,848 8,759 85.470 75,288 8,759 70,558 Feb. 30,400 142,619 8,741 101,672 142,619 8.741 100.407 Mar. 34,800 71,600 9,344 4,852 71.606 9.344 4.679 .\pril l'j,',i00 92,210 9,042 297 91,031 9.042 May 10,400 102,771 9,130 430 100,292 9,130 June 5,830 103,611 5,830 492 99,811 5,830 July 4,770 103,119 4,770 577 98,026 4.770 Aug. 3,570 102,542 3,570 535 96.119 3,570 Sept. 2,810 102,007 2.810 412 94.255 2,810 Oct. 7,010 101,595 6,473 307 92,555 6.473 Nov. 4,130 101,825 4,130 212 91,445 4,130 Dec. 13,600 101,613 5,253 46,759 89,940 5,253 33,734 Total or average 294,220 77.852 238,753 3,262 77.852 209,378 1917 Jan. 9,280 63,201 8,172 14,791 63,201 8,172 13,501 Feb. 13.2(K) 49,518 7,551 49,456 7,551 Mar. 13,800 55,167 9,344 53,883 9,344 April May 10,500 59.423 9,042 212 56.787 9,042 8,610 60.669 8,531 288 56.728 8.531 June 5,270 60.460 5.270 347 55.179 5.270 July. .3,140 60,113 3,140 410 53,543 3,140 Aug. 2,200 59,703 2,200 0. 379 51,812 2,200 Sept. 1,510 59,324 1,510 293 50.115 1.510 Oct. 1,560 59,031 1,560 224 48,544 1,560 Nov. 1,840 5?,807 1,840 149 46,994 1.840 Dec. 2,000 58.658 2,000 45.558 P.OOO Total or average 72710 60,160 14.791 2,302 60,160 13,501 THE CONTROL OP FLOODS BY RESERVOIRS. 439 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for 'prior'rights. 1 ^lood control completely coordinated with conservation coordinated with conservation | Reserve r emptied each summer to a level that wouk maintain constant eet maintained, other drafts draft through critical period; constant draft of 22 second-feet eservoir operating diagram | maintained, otherdrafts only as requir =dby reservoir operating diagram Flood control Constant draft from over-year storage (22 second- feet) in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Aausa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (22 second- feet) in acre-feet Variable summer draft from seasonally stored water in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1915 1,352 51,337 4,428 3,629 1,352 Jan. 1,222 49,308 8,412 12,355 1,222 Feb. 1,352 57,519 9,344 1,352 Mar. 1,309 238 68,323 9,042 1,309 416 238 Apr=l 1,352 343 74,618 9,344 1,352 2,090 341 May 1,309 434 81,891 8,967 1,309 4,759 414 June 1,352 508 77,842 7,010 1,352 5,717 468 July 1,352 464 70,305 3,989 1,352 5,717 407 Aug. 1,309 355 62,829 3,270 1.309 5,533 293 Sept. 1,352 268 55,694 2,770 1,352 214 Oct. 1,309 176 54,128 3,010 1,309 139 Nov. 1,352 52,680 3,580 1,352 Dec. Total or average 15,922 2,786 73,157 15,984 15,922 24,232 2,514 1916 1,352 51,328 8,759 51,935 1,352 ,Ian. 1,265 137,282 8,741 99,779 1,265 Feb. 1,352 66,897 9,344 603 1,352 Mar. 1,309 288 90,398 9,042 1,309 4,045 284 April 1,352 399 95,618 9,130 1,352 6,393 379 May 1,309 476 88,764 5,830 1,309 6,484 430 June 1,352 555 80,541 4,770 1,352 6,639 480 July 1,352 512 72,070 3,570 1,352 6,639 412 Aug. 1,309 391 63,667 2,810 1,309 6,425 295 Sept. 1,352 295 55,638 6,473 1,352 214 Oct. 1,309 196 54,609 4,130 1,309 131 Nov. 1,352 53,169 5,253 1,352 Dec. Total or average 15,965 3,112 77,852 152,317 15,965 36,625 2,625 1917 1,352 60,104 8,172 10,464 1,352 Jan. 1,222 49,456 7,551 1,222 Feb. 1,352 53,883 9,344 1,352 Mar. 1,309 208 56,787 9,042 1,309 208 April 1,352 276 56,728 8,531 1,352 276 May 1,309 327 55,179 5,270 1,309 327 June 1,352 379 53,543 3,140 1,352 379 July 1,352 345 51,812 2,200 1,352 345 Aug. 1,309 262 50,115 1,510 1,309 262 Sept. 1,352 198 48,544 1,560 1,352 198 Oct. 1,309 127 46,994 1.840 1,309 127 Nov. 1,352 45,558 2,000 1,352 Dec. 1 Total or average 15,922 2,122 60,160 10,464 15,922| 2,122 440 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Wate r drawn fron: reservoir only as required by Constant draft f 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and month at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing .\zu8a during flood season at rates less than 1,900 second- feet in acre-feet 1918 Jan. 2,020 58,658 2,020 44,206 2,020 Feb. 9,330 58,658 3,847 42,854 3,847 Mar. 73,200 64,141 9,249 19,393 47,115 9,249 3,595 April 17.000 108,699 9.042 321 106,119 9.042 May 10,000 11(),336 8,993 444 112,453 8,993 June 6,010 116,899 6,010 531 111,672 6,010 July 3,970 116,368 3,970 627 109,849 3.970 .•Vug. 2,840 115,741 2,840 581 107,896 2,840 Sept. 2,330 115,I()0 2,330 446 105,993 2.330 Oct. 2,930 114,714 2,930 341 104,264 2,930 Nov. 3,140 114,373 3,140 11,869 238 102,593 3,140 Dec. Total or average 4,370 102,266 4,370 29,745 101,072 4,370 27,459 137,140 58,741 61,007 3.529 58,741 31,054 1919 Jan. 3,3(10 72,,521 3,300 (1 72,261 3,300 I'cl.. 4,110 72,521 4,110 (1 70,909 4,110 Mar. (1,110 72,521 6,110 69,687 6,110 April (i,()10 72„'->21 6,010 238 68,335 6,010 May 3,810 72,283 3,810 323 66,796 3,810 June 1,890 71,960 1,890 .387 65,139 1,890 July 1,320 71, .573 1,320 458 (1 63,469 1,320 Aug. 93,') 71,115 935 422 61,697 935 Sept. 1,010 70,693 1,010 327 59,960 1,010 Oct. 2,040 70,306 2,040 248 58,358 2,040 Nov. 2.130 70,118 2.130 165 56,784 2,130 Dec. Total or average 5.340 09.953 5,209 7.081 55,332 5,209 38,005 37,874 7.081 2,568 37,874 1920 Jan. 3,2()0 63,003 3,260 8.130 54,111 3,260 Feb 12,700 54,873 5.854 885 52,759 5,854 Mar. 3fi,200 60,834 9,344 1,148 t) 58,340 9,344 April May 25,100 86,542 9.042 288 83,844 9.042 12,600 102,312 9.344 410 98,309 9,344 June 7,380 105,1.58 7.349 494 99,812 7..349 July 4,670 104,695 4.670 583 98,058 4.670 Aug. 3,200 104,112 3.200 541 96,151 3.200 Sept. 2,030 103,571 2.030 416 94,287 2.030 Oct. 2,000 103,155 2.000 317 92,587 2.000 Nov. 2,380 102.838 2.380 358 214 90,940 2,380 Deo. Total or average 2,210 102,266 2.210 30.538 89,437 2,210 16,619 113,730 60,683 41.059 3,263 60,683 16,619 THE CONTROL OF FLOODS BY RESERVOIRS. 441 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. Flood control completely coordinated with conservation coordinated with conservation Reservoir emptied ;ach Slimmer to a level that would maintam 3onstant Jeet maintained, other drafts draft through critical period; constant draft of 22 second-feet reservoir operating diagram maintained, othe r drafts only as required by reservoir operating diagram Flood control Constant draft from Evapora- tion from Waste Stage of reservoir Passed by dam for prior rights in acre-feet water passing Azusa during Constant draft from Variable summer draft Evapora- tion from Waste Year and month over-year storage (22 second- feet) in acre-feet reservoir surface in acre-feet over spillway in acre-feet at beginning of month in acre-feet flood season at rates less than 1,900 second- over-year storage (22 second- feet) in acre-feet from seasonally stored water in acre-feet reservoir surface in acre-feet over spillway in acre-feet feet in acre-feet 1918 1,352 44,206 2,020 1,352 Jan. 1,222 42,854 3,847 1,222 Feb. 1,352 47,115 9,249 3,595 1,352 Mar. 1,309 315 106,119 9,042 1,309 6,603 307 April 1,352 436 105,858 8,993 1,352 8,422 412 May 1,309 514 96,679 6,010 1,309 8,388 454 June 1,352 601 86,528 3,970 1,352 8,668 496 July 1,352 551 76,012 2,840 1,352 8,606 422 Aug. 1,309 420 65,632 2,330 1,309 8,329 297 Sept. 1,352 319 55,697 2,930 1,352 214 Oct. 1,309 212 54,131 3,140 1,309 139 Nov. 1,352 52,683 4,370 1,352 Dec. Total or average 15,922 3,368 58,741 3,595 15,922 49,016 2,741 1919 1,352 51,331 3,300 1,352 Jan. 1,222 49,979 4,110 1,222 Feb. 1,352 48,757 6,110 1,352 Mar. 1,309 230 47,405 6,010 1,309 182 April 1,352 305 45,914 3,810 1,352 244 May 1,309 361 44,318 1,890 1,309 284 June 1,352 420 42,725 1,320 1,352 329 July 1,352 385 41,044 935 1,352 299 Aug. 1,309 293 39,393 1,010 1,309 230 Sept. 1,352 222 37,854 2,040 1,352 171 Oct. 1,309 143 36,331 2,130 1,309 109 Nov. 1.352 34,913 5,209 1,352 Dec. Total or average 15,922 2,359 37,874 15,922 1,848 1920 1,352 33,692 3,260 1,352 Jan. 1,266 32,340 5,854 1,265 n Feb. 1,352 37,921 9,344 1,352 Mar. 1,309 284 63,425 9,042 1,309 236 April 1,352 401 77,938 9,344 1,352 2,766 339 May 1,309 476 76,737 7,349 1,309 3,510 395 June 1,352 555 71,554 4,670 1,352 3,565 446 July 1,352 512 66,191 3,200 1,352 3,627 395 Aug 1,309 391 60.817 2,030 1,309 3,510 290 Sept. 1,352 295 55,708 2,000 1,352 214 Oct. 1,309 194 54,142 2,380 1,309 139 Nov 1,352 52,694 2,210 1,352 Dec. Total or average 15,965 3,108 60,683 15,965 16,978 2,454 28—52411 442 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Water drawn f ronr reservoir only as required by Constant draft o f 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and month at Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1921 Jan. 5,160 71,728 4,405 19,991 71,466 4,405 18,459 Feb. 4,490 52,492 4,490 52,410 4,490 Ma-. 15,400 52,492 7,288 51,188 7,288 April 6,070 60,604 6,070 214 57,948 6,070 May 15,700 60,390 6,835 295 56,433 6,835 June 8,i)80 68,960 7,920 379 63,664 7,920 July 3,830 69,641 3,830 450 63,054 3,830 Aug. 2,450 69,191 2,450 416 61,284 2,450 Sept. 1.840 68,775 1,840 323 59,549 1,840 Oct. 2,040 68,452 2,040 244 57,947 2,040 Nov. 1,800 68,208 1,800 163 56,375 1,800 Dec. 119,000 68,045 5,045 42,364 54,923 5,045 41,740 Total or average 186,760 54,013 62,355 2,484 54,013 60,199 1922 Jan. 62,100 139,636 9,344 108,684 125,786 P. 344 107,332 Feb. 88,900 83,708 8,440 98.166 69,858 8,410 83.316 Mar. 47,800 66,002 9,344 3,576 65,780 9,344 2,882 April 31,400 100,882 9,042 321 100,002 9,042 May 24,700 122,919 9,344 482 120,734 9,344 June 14,400 137,793 9,042 605 134,264 9,042 July 9,100 142,546 8,576 720 137,722 8,576 Aug. 5,080 142,350 5,080 670 136,194 5,080 Sept. 3,290 141,080 3,290 516 134,196 3,290 Oct. 3,110 141,164 3,110 393 132,391 3,110 Nov. 5,310 140,771 4,519 37,066 246 130,664 4,519 25.655 Dec. 21,500 104,250 8,456 54.0i'3 104.249 8,456 52,740 Total or average 316,690 87,587 301,585 3.953 87,587 271,925 1923 Jan. 7,130 63,201 6,968 13,408 63.201 0,968 12,056 Feb. 7,830 49,955 7,791 49,955 7,791 Mar. 7,.320 49.994 7,320 48,772 7,320 April 8,330 49.994 8,079 190 47,420 8,079 May 5,480 50,055 5,480 258 40,180 5,480 June 3,700 49,797 3,700 309 44,584 3,700 July 2,420 49,488 2,420 363 42,987 2,420 Aug. 1,990 49,125 1,990 337 41,304 1,990 Sept. 1,750 48,788 1,750 262 39,653 1,750 Oct. 1,710 48,526 1,710 198 38,112 1,710 Nov. 1,960 48,328 1,960 131 30,589 1,960 Doc. 2,130 48,197 2,130 35,169 2,130 Total or average 51.750 61,298 13.408 2,048 51,298 12,056 THE CONTROL OF FLOODS BY RESERVOIRS. 443 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. 444 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Flood control alone Flood control partially Wat< r drawn from reservoir only as required by Constant draft of 22 second- reservoir operating diagram only as required by Flood Flood Run-off control control Year and at water water month Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet 1924 Jan. 2,170 48,197 2,170 33,817 2,170 Feb. 1,790 48,197 1,790 32,465 1,790 Mar. 4,130 48,197 3,714 31,200 3,714 April 6,190 48,613 6,190 188 30,264 6,190 May 3,650 48,425 3,650 252 28,814 3,050 June 1,660 48,173 1,660 303 27.276 1,660 July 1,000 47,870 1,000 359 25.753 1,000 Aug. 756 47,511 756 329 24.153 756 Sept. 744 47,182 744 256 22,579 744 Oct. 873 46,926 873 196 21,103 873 Nov. 1,190 46,730 1,190 129 19,628 1,190 Dec. 1,780 46,601 1,780 18,240 1,780 Total or average 25,933 25,517 2,012 25,517 1925 Jan. 1.710 46,601 1,710 16,888 1,710 Feb. 1,620 46,001 1,620 15..536 1,620 Mar. 2,510 46,601 2,423 14,314 2,423 April 7,200 46,688 5,765 184 13,049 5,765 May 3,050 47,939 3,050 252 13,086 3,(150 June 1,840 47,087 1,840 295 11,629 1,840 July 824 47,392 824 349 10,189 824 Aug. 621 47,043 621 329 8,696 621 Sept. 492 46,714 492 254 7,227 492 Oct. 873 46.460 873 194 5,837 873 Nov. 1,010 46,206 1,010 127 4,433 1,010 Dec. 1,650 46,139 1,650 3,096 1,650 Total or nvcrage 23,400 21.878 1,984 21,878 1926 Jan. 1,540 46,139 1„540 1,744 1,540 Feb. 7,940 46,139 5,485 3»2 5,485 Mar. 3,650 48,594 3,650 1,625 3,650 April May 69,000 48,594 8,233 274 273 8,233 13,000 109,087 9,142 434 59,572 9,142 June 5,500 112.511 5,500 520 61,785 5,500 July 3,120 111,991 3,120 611 60,127 3,120 Aug. 2,070 111,380 2.070 567 .58.367 2,070 Sept. 1,580 110,813 1,580 436 56,642 1,580 Oct. Nov. Dec. 110,377 55,049 Total or average 107.400 40,320 2,842 40.320 THE CONTROL OF FLOODS BY RESERVOIRS. 445 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet. feet passed for prior rights. 446 WATER RESOURCES OF CALIFORNIA. TABLE 16a (Concluded). SAN GABRIEL COMPARISON OF WATER YIELD FOR USE OF RES Monthly Summary of Computa (For corresponding yearly sum Height of dam 383 feet. Capacity of reservoir 180,000 acre-feet. Natural flow up to 152 second- Run-off at Azusa in acre-feet Flood control alone Water drawn from reservoir only as required by reservoir operating diagram Flood control partially Constant draft of 22 second- only as required by Year and month Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reserv-oir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Total for period, Jan. 1, 1897. to Ocf.1, 1926 Average for period, Jan.1, 1897, to Oct. 1, 1926 3.731,977 125.445 1.513,303 50,867 "2,076,091 "69,785 87,430 2,939 7,426 250 1,513,303 50.867 1,672,152 1-56.207 • In the cumpjtitions for this table the period of analysis cbsed with 47,727 acre-feet more water in storage than at the beginning, thecTiivalent of IGOl v:ra-feef per season. Since in the computations this water was stored in the last year of the psriod of analysis, the exact yield of flood control water for the p3riod is greater than here shown by this amount. THE CONTROL OF FLOODS BY RESERVOIRS. 447 RESERVOIR ON SAN GABRIEL RIVER. THREE STEPS IN COORDINATING THE ERVOIR SPACE. tions Carried Out on a Daily Basis. mary, see Table 16, page 182.) Maximum controlled flow at Azusa 1,900 second-feet. Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. coordinated with conservation feet maintained, other drafts reservoir operating diagram Flood control completely coordinated with conservation Reservoir emptied each summer to a level that would maintain constant draft through critical period; constant draft of 22 second-feet maintained, other drafts only as required by reser\-oir operating diagram Constant draft from over-year storage (22 second- feet) in acre-feet Evapora- tion from reservoir surface in acre-feet Waste over spillway in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (22 second- feet) in acre-feet Variable summer draft from seasonally stored water in acre-feet Evapora- tionfrom reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 473,905 15,930 76,867 2,584 3,351 113 1,513,303 50,867 b1 ,01 0,662 b33,972 473,905 15,930 676,322 22,734 65,386 2,198 Total for period, Jan.1, 1897, to Oct. 1, 1926 Average for period, Jan.1, 1897, to Oct. 1, 1926 *> These figures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the e.xact period, of analysis. In the computations from which this table is prepared, the water in storage on October 1, 1926, the end of the period, is less by this amount than on .January I, 1897, the beginning of the period. Since in the computations this water was released as flood control water during t he first flood season of the period , the exact yield of flood control water for the period, is less than here shown by this amount. 448 WATER RESOURCES OF CALIFORNIA. TABLE 17a. SAN GABRIEL RESER COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam. 383 feet. Capacity of reservoir, 180,000 acre-feet Constant draft of 22 second-feet maintained, other drafts only Run-off at as required by reservoir operating diagi am Year and month Flood control Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1897 Jan. 3,617 62,650 3,617 11.779 1,352 Feb. 19,146 49,519 7,262 4,628 1,222 Mar 28,623 55,553 9.344 1,352 April 17,519 73,480 9,042 1,309 235 May 8,851 80,413 8,126 1.352 353 June 4,033 79,433 4,033 1,309 412 July 2,343 77,712 2,343 1,352 485 Aug. 1,613 75,875 1,013 1,352 440 Sept. 1,226 74,083 1,226 1,309 337 Oct. 5,564 72,437 2,622 1,352 258 Nov. 1,860 73,769 1,860 1,309 171 Dec. 1,875 72,289 1,875 1,352 Total or average 96,270 52,963 16,407 15,922 2,691 1898 Jan. 2,453 70,937 2,453 10.849 1.352 Feb. 2,241 58,736 2,241 1,222 Mar. 2,131 57,514 2,131 1,352 April 1,950 56,162 1,950 1,309 202 May 2,213 54,651 2,213 1,352 270 June 1,1.59 53,029 1,159 1,309 325 July 672 51,395 672 1,352 369 Aug. 456 49,674 456 1,352 337 Sept. 467 47,985 467 1,309 256 Oct. 533 46,420 533 1,352 192 Nov. 580 44,876 580 1,309 125 Dec. 832 43,442 832 1,352 Totiil or average 15,687 15,687 10,849 15.922 2.076 1899 Jan. 1,414 42,090 1,414 1,352 Feb. 1,244 40,738 1.244 1,222 Mar. 1,623 ,39,516 1,623 1,352 April 1,262 38,164 1,262 1,309 161 May 842 36,694 842 1,352 214 June 565 35,128 565 1,309 248 July 221 33,571 221 1.352 288 Aug. 295 31,931 295 1.3.52 260 Sept. 220 30,319 220 1,309 198 Oct. 083 28.812 683 1,352 147 Nov 847 27,313 847 1.309 91 Dec. Total or avcriige 1,247 25,913 1,247 1.352 10,463 10.463 15.922 1.607 1900 Jan. 1.968 24.561 1.968 1.352 Feb. 1,111 23.209 1.111 1.222 Mar. 1.230 21.987 1.230 1.352 April 1,012 20.635 1,012 1.309 115 May 2,275 19,211 2,275 1,352 147 June 893 17,712 893 1,309 180 July 369 10,223 309 1,352 192 Aug. 246 14,679 246 1,352 169 Sept. 238 13,1,58 238 1,309 121 Oct. 307 11,728 307 1,352 95 Nov. 11,068 10,281 1,058 1.309 59 Dec. Total or 1,269 18,923 1,260 1.352 average 21,986 11,976 15.922 1,078 THE CONTROL OF FLOODS BY RESERVOIRS. 449 VOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam , 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, ottier drafts only as equired by reservoir operating diagram Flood control Year and Stage of reservoir at beginniEg of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1897 122,650 3.617 10,611 2,520 Jan. 109,519 7,262 4,478 2,276 Feb. 114,649 9,344 2,520 Mar. 131,408 9,042 2,439 363 April 137,083 8,126 2,520 494 May 134,794 4,033 2,439 583 •June 131,772 2,343 2,520 674 July 128,578 1,613 2.520 621 Aug. 125,437 1,226 2,439 472 Sept. 122,526 2,622 2,520 357 Oct. 122,591 1,860 2,439 238 Nov. 119,914 1,875 2,520 Dec. Total or average 52,963 15,089 29,672 3,802 1898 117,394 2,453 2,520 Jan. 114,874 2,241 2,276 Feb. 112,598 2,131 2,520 Mar. 110,078 1.950 2,439 313 April 107,326 2,213 2,520 410 May 104,396 1,159 2,439 490 June 101,467 672 2,520 565 July 98,382 456 2,520 516 Aug. 95,346 467 2,439 391 Sept 92,516 533 2,520 293 Oct. 89,703 580 2,439 192 Nov. 87,072 832 2,520 Dec. Total or 15,687 29,672 3,170 average 1899 84,552 1,414 2,520 Jan. 82,032 1,244 2,276 Feb. 79,756 1,623 2.520 Mar. 77,236 1,262 2,439 246 April 74,551 842 2,520 325 May 71,706 565 2,439 383 June 68,884 221 2,520 440 July 65,924 295 2,520 399 Aug. 63,005 220 2,439 301 Sept. 60,265 683 2,520 224 Oct. 57,521 847 2,439 143 Nov. 54,939 1,247 2,520 Dec. Total n average 10,463 29,672 2,461 1900 52,419 1,968 2,520 Jan. 49,899 1,111 2,276 Feb. 47,623 1,230 2,520 Mar. 45,103 1,012 2,439 176 April 42,488 2,275 2.520 230 May 39,738 893 2,439 264 June 37,035 369 2,520 299 July 34,216 246 2,520 268 Aug. 31,428 238 2,439 200 Sept. 28,789 307 2,520 145 Oct. 26,124 1,058 2,439 95 Nov. 33,600 1,269 2.520 Dec. Total or average 11,976 29,672 1,677 450 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam, 383 feet. Capacity of reservoir, 180,000 acre-feet Constant draft of 22 second-fee maintained, other drafts only Run-off at as required by reservoir operating diagram Year and month i Flood control Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1901 Jan. 10,391 17,571 6,661 1,352 Feb. 38.709 19,949 8,350 1,222 Mar. 13,589 49,086 9,138 1,352 .\pril 6,545 52.185 6,545 1,309 192 May 7,440 50,684 6,990 1,352 260 June 3,749 49,522 3,749 1,309 305 July 1.845 47,908 1,845 1,352 353 Aug. 1.240 46,203 1,240 1,352 321 Sept- 1,012 44,530 1,012 1,309 246 Oct. 1,476 42,975 1,476 1,352 184 Nov. 1,904 41.439 1,904 1,309 115 Dec. 1,660 40,015 1,660 1,352 Total or average 89,560 50,570 15,922 1,976 1902 Jan. 1,722 38,663 1,722 1,352 Feb. 2,055 37,311 2,055 1,222 Mar. 6,088 36,089 5,590 1,352 April 3,928 35,235 3,928 1.309 153 May 2,398 33,773 2,398 1,352 204 June 1,190 32,217 1,190 1,309 236 July 676 30,672 676 1,352 272 Aug. 430 29,048 430 1,352 246 Sept. 298 27,450 298 1,309 186 Oct. 430 25,955 430 1,352 139 Nov. 1,131 24,464 1,131 1,309 87 Dec. 1,968 23,068 1,968 1,352 Total or average 22,314 21,816 15,922 1.523 1903 Jan. 9,100 21,716 2.536 1,352 Feh 5,665 26,928 5,497 1,222 Mar. 15,802 25.874 7.898 1,352 April 47,127 32,426 9.042 1,309 208 May 13,343 68,994 9.116 1,352 323 Jdne 5,653 71,546 5.653 1,309 385 July 2,644 69.852 2,644 1,352 446 Aug. 1,783 68,054 1,783 1.352 410 Sept. 1,488 66,292 1,488 1.309 313 Oct. 1.476 64,670 1,476 1,352 236 Nov. 1,428 63,082 1,428 1,309 155 Dec. 1,476 61.618 1,476 1,352 Total or average 106.085 50.037 15,922 2.476 1904 Jan. 1,500 60.266 1,500 1,352 Feb. 2,744 58,914 2,177 1,265 Mar. 6,813 58,216 4.724 1.352 April May 5,337 58,953 5,337 1,309 208 4,089 57,436 4.089 1,352 280 June 1.517 55,801 1.517 1,309 329 July 861 54,166 861 1,352 383 Aug. 793 52.431 793 1,352 349 Sept. 643 50,730 643 1,309 266 Oct. 738 49,155 738 1,352 206 Nov. 762 47,597 762 1,309 133 Dec. 1.039 46.155 1,039 1,.352 Total or average 26,836 24,180 15,965 2,154 THE CONTROL OF FLOODS BY RESERVOIRS. 451 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operating diagra m Flood control Year and Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1901 31,080 6,661 2,.520 Jan. 32,290 8,350 2,276 Feb. 60,373 9,138 2,520 Mar. 62,304 6,545 2,439 214 April 59,651 6,990 2,520 284 May 57,297 3,749 2,439 331 June 54,527 1,845 2,520 381 July 51,626 1,240 2,520 341 Aug. 48,765 1,012 2,439 256 Sept. 46,070 1,476 2,520 188 Oct. 43,362 1,904 2,439 121 Nov. 40,802 1,660 2,520 Dec. Total or average 50,570 29,672 2,116 1902 38,282 1,722 2,520 Jan. 35,762 2,055 2,276 Feb. 33,486 5,590 2,520 Mar. 31,464 3,928 2,439 143 April 28,882 2,398 2,520 182 May 26,180 1,190 2,439 208 June 23,533 676 2,520 232 July 20,781 430 2,520 202 Aug 18.059 298 2,439 145 Sept. 15.475 430 2,520 99 Oct. 12,856 1,131 2.439 58 Nov.- 10,359 1,968 2,520 Dec. Total or 21,816 29,672 1,269 average 1903 7.839 2,536 2,520 Jan. 11,883 5,467 2,276 Feb. 9,775 7,858 2,520 Mar. 15,159 9,042 2,439 171 April 50,634 9,116 2,520 268 May 52,073 5,653 2,439 311 June 49,323 2,644 2,520 359 July 46.444 1,783 2,520 321 Aug. 43,603 1,488 2,439 240 Sept. 40,924 1,476 2,520 176 Oct. 38,228 1,42» 2,439 113 Nov. 35,676 1,476 2,520 Dec. Total or average 50,037 29,672 1.959 1904 33,156 1,500 2,520 Jan. 30,636 2,177 2,358 Feb. 28,845 4,724 2,520 Mar. 28,414 5,337 2,439 135 April 25,840 4,089 2,520 173 May 23.147 1,517 2,439 194 June 20,514 861 2,520 216 July 17,778 793 2,520 184 Aug. 15,074 643 2.439 129 Sept. 12,506 738 2,520 87 Oct. 9,899 762 2,439 50 Nov. 7,410 1,039 2,520 Dec. Total or 24,180 1 29,754 j 1,168 1 average 452 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam, 383 feet. Capacity of reservoir, 180,000 acre-feet Constant draft f 22 second-feet maintained, other drafts only Run-ofF at Azusa in acre-feet as required by reservoir operating diagram Year and month Stage of reservoir at beginning of month in acre-feet Passed oy dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporatioa from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1905 Jan. 2,251 44,803 2,251 1,352 Feb. 25,S80 43,451 8,206 6,204 1,222 Mar. 75,140 53,699 9,281 16,231 1,352 April 19,580 101,975 9,042 1,309 311 May 17.090 1 10,893 9,344 1,352 438 June 8,271 116,849 7,960 1,309 529 July 5,103 115,322 5,103 1,352 621 Aug. 2,631 113,349 2,631 1,352 571 Sept. 1,869 111,426 1,869 1.309 436 Oct. 1.770 109,681 1,770 1.352 329 Nov. 2,660 108,000 2,660 3,610 1,309 220 Dec. 2,470 102,861 2,470 6,944 1,352 Total or average 164,715 62,587 32,989 15,922 3,455 1906 Jan. 4,240 94,565 3,033 33,008 1.352 Feb. 3,960 60,212 3,960 1,222 Mar. 129,000 58,990 7,561 30,250 1,352 April 34,600 148,827 9,042 20,735 1,309 381 May 21,000 151,960 9,344 1,352 541 June 15,500 161,723 9,042 1,309 674 July 9,350 166,198 8,664 1,352 803 Aug. 4,490 164,729 4,490 1,352 738 Sept. 2.840 162,639 2,840 1,309 567 Oct. 2,450 160,763 2,450 1.352 430 • Nov. 2,400 158,981 2,400 5.941 1,309 286 Dec. Total or average 11,600 151,445 4,030 94,462 1,352 241,430 67.456 184.996 15,922 4,420 1907 Jan. 58,400 63,201 9,217 56,159 1.352 Feb. 47,100 54,873 8.439 29,904 1,222 Mar. 116,000 62,408 9,344 45,814 1.352 April May 58,400 121,898 9,042 453 1.309 391 21,500 169,103 9,344 1.352 585 June 15,100 179,322 9.042 1,309 720 3,351 July 8,360 180,000 7,920 1,352 847 Aug. 5,.390 178.241 5,390 1,3.52 781 Sept. 3,580 176,108 3,580 1,309 599 Oct. 4,090 174,200 4,090 3,106 1,352 450 Nov. 3,800 169,292 3.800 53,565 •1,309 254 Dec. 3.600 114,164 3,600 12,164 1,352 Total or average 345,320 82.808 201.165 15,922 4,627 3.351 1908 Jan. 11.100 100,648 4,973 24.273 1.352 Vvh. 15,000 81,150 8,741 35,256 1.265 Mar. 12,700 .50,888 9,255 1,352 April 9,280 .W.981 8,056 l,30y 196 May 7. IPO 52.100 7.139 1,.'<52 262 June 4.190 50.537 4,190 l.SO'.l 309 July 2,560 48,'tl9 2,,')60 1,352 359 Aug. 2,210 47,208 2.210 1.3.52 325 Sept. 1.820 4.5,531 1.820 1,309 252 Oof. • 2,070 43,970 2,070 1,352 186 Nov. 1,<160 42.432 1,960 1.309 123 Dec. Total or avcriiKfi 2,870 41.000 2,870 1,352 72,950 56,444 59,529 15,965 2,012 THE CONTROL OF FLOODS BY RESERVOIRS. 453 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam, 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operating diagram Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet Year and month 1905 4,890 2,251 2,520 Jan. 2,370 8,206 2,276 Feb. 17,768 9,281 2 520 Mar. 81,107 9,042 2.439 268 April 88,938 9,344 2,520 377 May 93,787 7,960 2,439 464 June 91,195 5,103 2,520 527 July 88,148 2,631 2.520 482 Aug. 85,146 1,869 2,439 365 Sept. 82,342 1,770 2,520 272 Oct. 79,550 2,660 2,439 176 Nov. 76.935 2,470 2,520 Dec. Total or average 62,587 29,672 2,931 1906 74,415 3,633 2,520 Jan. 72,502 3,960 2,276 Feb. 70,226 7,561 9,428 2,520 Mar. 179,717 9,042 2,439 468 April 202,368 9,344 2,520 658 May 210,846 9,042 2,439 815 June 214,050 8.664 2,520 960 July 211,256 4,490 2,520 882 Aug. 207,854 2,840 2,439 672 Sept. 204,743 2,450 2.520 510 Oct. 201,713 2,400 2,439 335 Nov. 198,939 4,030 80,788 2,520 Dec. Total or average 67,456 90,216 29,672 5,300 1907 123,201 9,217 54,991 2,520 Jan 114.873 8,439 28,878 2,276 Feb. 122,380 9,344 44,618 2,520 Mar. 181,898 9,042 360 2,439 496 April 227,961 9,344 2,520 724 May 236,873 9,042 2,439 886 June 239,606 7,920 2,520 1,047 July 236,479 5,390 2,520 958 .\ug. 233,001 3.580 2,439 736 Sept 229,826 4,090 2,520 557 Oct. 226,749 3,800 49.817 2,439 329 Nov. 174,164 3,600 11,787 2,520 Dec. Total or average 82,808 190,451 29.672 5,733 1908 159,857 •1,973 24,010 2,520 Jan. 139,454 8,741 33,168 2,358 Feb. 110,187 9,255 2,520 Mar. 111,112 8,656 2,439 3)7 April 108.980 7,139 2,520 420 May 106,091 4,190 2,439 494 June 103,158 2,560 2,520 573 July 100,065 2,210 2,520 524 Aug. 97,021 1,820 2,439 397 Sept. 94,185 2,070 2,520 297 Oct. 91,368 1,960 2,439 194 Nov. 88,735 2,870 2,520 Dec. Total or average 56,444 57,178 29,754 3,216 454 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (F'or corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam, 383 feet. Capacity of reservoir, 180,000 acre-feel Constant draft of 22 second-feet maintained, other drafts only Run-off at Azusa in acre-feet as required by reservoir operating diagram Year and month Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet Flood control water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1909 Jan. 25,500 39,648 5,596 8,681 1,352 Feb. 59,400 49,519 8,440 41,897 1,222 Mar. 26,300 57,360 9,344 1,352 April 28,000 72,964 9,042 1,309 262 May 15,200 90,351 9,344 1,352 381 June 8,570 94,474 8,319 1,309 460 July 5,040 92,956 5,040 1,352 537 Aug. 3.120 91,067 3,120 1,352 494 Sept. 2,320 89,221 2,320 1,309 377 Oct. 2,310 87,535 2,310 1,352 286 Nov. 2,880 85,897 2,880 1,309 188 Dec. 20,900 84,400 6,346 24,763 1,352 Total or :iveraj?e 199,540 72,101 75,341 15,922 2,985 910 Jan. 69,500 72,839 9,344 81,516 1,-352 Feb. 11,500 50,127 8,435 2,292 1,222 Mar. 9,590 49,678 9,029 1,352 April 8,270 48,887 8,120 1,309 186 May 5,050 47,542 5,050 1,352 250 June 3,500 45,940 3,560 1,309 291 July 2,450 44,340 2,450 1,352 337 Aug. 1,710 42,651 1,710 1,352 307 Sept. 1,370 40,992 1,370 1,309 234 Oct. 1,560 39,449 1,560 1,352 174 Nov. 1,870 37,923 1,870 1,309 113 Dec. 2,020 36,501 2,020 1,352 Total or average 118,450 54,518 83,808 15,922 1,892 1911 Jan. 37,200 35,149 6,441 6,949 1,352 Feb. 44,300 57,607 8,440 38,010 1,222 Mar. 122,000 54,235 9,344 55,857 1,352 Anri! 28,200 109,682 9,042 1,309 335 May 16,600 127,196 9,344 1,352 478 June 7,500 132,622 7,322 1,309 579 July 5,230 130,912 5,230 1,352 676 Aug. .3,610 128,884 3,610 1,352 623 Sept 2,830 120,909 2,830 1,309 476 Oct. 3,140 125,124 3,140 1,352 361 Nov. 2,800 123,411 2,800 1,061 1,309 238 Dec. 2,870 120,803 2,870 22,352 1,352 Total or average 276.280 70.413 124,229 15,922 3,766 1912 Jan. 2,710 97,099 2,710 1,352 Feb. 2,2.30 95,747 2,230 1,205 Mar. 22,900 94,482 8,199 490 1,352 April 18,000 107,335 8,515 1,309 315 May 10,900 115,196 8.828 1,352 442 June 4,990 115,474 4,990 1,309 625 July 3.060 113,640 3,0f.0 1,352 613 Aug. 1.960 111,675 1,960 1,.352 565 Sept. 1.550 109,758 1,.5.50 1,309 430 Oct. 1,830 108,019 1,830 1,352 327 Nov. 1,730 106,340 1,730 1,309 216 Dec. 1,700 104,815 1,760 1,352 Total or average 73,620 47,362 496 15,965 3,433 THE CONTROL OF FLOODS BY RESERVOIRS. 455 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operating diagra m Flood control Year and Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1909 86,215 5,596 2,520 Jan. 103,599 8,440 35,296 2,276 Feb. 116,987 9,344 2,520 Mar. 131,423 9,042 2,439 375 April 147,567 9,344 2,520 525 May 150,378 8,319 2,439 631 June 147,559 5,040 2,520 734 July 144,305 3,120 2,520 672 Aug. 141,113 2,320 2,439 512 Sept. 138,162 2,310 2,520 385 Oct. 135,257 2,880 2,439 254 Nov. 132,564 6,346 11,759 2,520 Dec. Total or 72,101 47,055 29,672 4,088 average 1910 132,839 9,344 80,362 2,520 Jan. 110,113 8,435 1,945 2,276 Feb. 108,957 9,029 2,520 Mar. 106,998 8,120 2,439 307 April 104,402 5,050 2,520 407 May 101,475 3,560 2,439 478 Jane 98,558 2,450 2,520 555 July 95,483 1,710 2,520 506 Aug. 92,457 1,370 2,439 385 Sept. 89,633 1,560 2,520 288 Oct. 86,825 1,870 2,439 188 Nov. 84,198 2,020 2,520 Dec. Total or 54,518 82,307 29,672 3,114 average 1911 81,078 6,441 2,520 Jan. 109,917 8,440 29,679 2,276 Feb. 113,822 9,344 55,275 2,520 Mar. 168,683 9,042 2,439 438 April 184,964 9,344 2,520 617 May 189,083 7,322 2,439 740 June 186,082 5,230 2,520 865 July 182,697 3,010 2,520 793 Aug. 179,384 2,830 2,439 607 Sept. 176,338 3,140 2,520 458 Oct. 173,360 2,800 2,439 301 Nov. 170,620 2,870 11,071 2,520 Dec. Total or average 70,413 96,025 29,672 4,819 1912 157,029 2,710 2,520 Jan. 154,509 2,230 2,358 Fob. 152,151 8,199 2,520 Mar. 164,332 8,515 2,439 420 April 170,958 8,828 2,520 575 May 169,935 4,990 2,439 686 June 166,810 3,060 2,520 799 July 163,491 1,900 2,520 731 Aug. 160,237 1,550 2,439 557 Sept. 157,241 1,830 2,520 420 Oct. 154,301 1,730 2,439 280 Nov. 151,582 1,760 2,520 Dec. Total or average 47,362 29,754 4,471 456 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Compute (For orre ponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Heiflht of dam, 383 feet. Capacity of resarvoir, 180,000 acre-feet Constant draft of 22 second-feet maintained, other drafts only Rim-off at as required by reservoir operating diagram Year and month Flood control Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for priorrights in acre-feet water passing Aziisa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1913 Jan. 2,910 103,463 2,910 4.136 1.352 Feb. 13,200 97,975 4.753 24.767 1,222 Mar. 10,200 80,433 8.759 10,660 1,352 April 7,140 69,862 7.091 1,309 232 May 4,970 68,370 4,970 1,352 309 June 2,890 66,709 2,890 1,309 367 July 1,690 65,033 1,690 1,352 426 Aug. 1,070 63.255 1,070 1,352 391 Sept. 893 61.512 893 1,309 297 Oct. 910 59.906 910 1,352 224 Nov. 2,280 58,330 2,280 1,309 147 Dec. 2,170 56,874 2,170 1,352 Total or average 50,323 40,386 39,503 15,922 2.393 1914 .Ian. 61,400 55,522 6,271 47,159 1,352 Feb. 121,000 62,140 8,440 58,284 1,222 Mar. 48,000 115,194 9,344 52,388 1,352 April 21,400 100,110 9,042 1,309 305 May 16,900 110,854 9,344 1,352 428 June 9,580 116,630 8,585 1,309 530 July 5,570 115,786 5,570 1,352 631 Aug. 3,630 113,803 3,630 1,352 572 Sept. 2,730 111,879 2,730 1,309 436 Oct. 2,770 110.134 2,770 1,352 331 Nov. 2,440 108.451 2,440 1,309 220 Dec. 4,290 106,922 4,290 40.981 1,362 Total or average 299,710 72,456 198,812 15,922 3,453 1915 Jan. 7,380 64,589 4.428 8,659 1,352 Feb. 30,200 67.530 8,412 20,577 1.222 Mar. 21,500 57.519 9.344 1,352 April 17,300 68.323 9,042 1,309 238 May 20.400 75.034 9,344 1,352 343 June 11,400 84.395 8,967 1,309 434 July 7,010 85.085 7,010 1,352 508 Aug. 3,980 83.225 3.980 1,352 464 Sept. 3,270 81,409 3,270 1,309 365 Oct. 2,770 79.745 2.770 1,352 268 Nov. 3.010 78.125 3.010 1,309 176 Dec. 3.580 76.640 3.580 1.352 Total or average 131,800 73,157 29.230 15.922 2,786 1916 Jan. 148.000 75,288 8.759 70,558 1,352 Feb. 39,400 142,619 8.541 100,407 1,265 Mar. 34.800 71,606 9.344 4,679 1,352 April May 19.900 91.031 9.042 1,309 288 10.400 100.292 9,130 1,352 399 June 5.830 99.811 5,830 1.309 476 July 4.770 98.026 4,770 1.352 555 Aug. 3,570 96,119 3,670 1.352 612 Sept. 2,810 94.255 2,810 1.309 391 Oct. 7,010 92.555 6.473 1.352 295 Nov. 4,130 91.445 4.130 1.309 196 Dec. Tntftl nr 13,000 89.940 5.253 33.734 1.352 1 utai ur average 294,220 77.852 209.378 16.965 3.112 THE CONTROL OF FLOODS BY RESERVOIRS. 457 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam, 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, otiier drafts only as required by reservoir operating diagram Flood control Year and Stage of reservoir at beginning of month in acre-feet Passed by dam for water passing Azusa during flood season at Constant draft from over-year Evaporation from reservoir Waste over spillway in acre-feet month prior rights in acre-feet rates less than 1,900 second- feet in storage (41 second-feet) in acre-feet surface in acre-feet acre-feet 1913 149,062 2.910 2,520 Jan. 146,542 4,753 16,941 2,276 Feb. 135,772 8,759 7,782 2,520 Mar. 126,911 7,091 2,439 345 April 124,176 4,970 2,520 460 May 121,196 2,890 2,439 541 June 118,216 1,690 2,.520 629 July 115,067 1,070 2,520 675 Aug. 111,972 893 2,439 436 Sept. 109,097 910 2,520 327 Oct. 106,250 2,280 2,439 216 Nov. 103,595 2,170 2,520 Dec. Total or average 40,386 24,723 29,672 3,529 1914 101,075 6,271 31,544 2,520 Jan. 122,140 8,440 57,228 2,276 Feb. 175,196 9,344 51,782 2,520 Mar. 159,550 9,042 2,439 424 April 169,045 9,344 2,520 579 May 173,502 8,585 2,439 696 June 171,362 5,570 2,520 815 July 168,027 3,630 2,520 746 Aug. 164,761 2,730 2,439 569 Sept. 161,753 2,770 2,520 430 Oct. 158,803 2,440 2,439 284 Nov. 156,080 4,290 28,967 2,520 Dec. Total or 72,456 169.521 29,672 4,543 average 1915 124,593 4,428 8,211 2,520 Jan. 116,814 8,412 19,214 2,276 Feb. 117,112 9,344 2,520 Mar. 126,748 9,042 2,439 353 April 132,214 9,344 2,520 494 May 140,250 8,967 2,439 603 June 139,647 7,010 2,520 704 July 136,423 3,980 2,520 644 Aag. 133,259 3,270 2,439 492 Sept. 130,328 2,770 2,520 369 Oct. 127,439 3,010 2,439 244 Nov. 124,750 3,580 2,520 Dec. Total or average 73,157 27,425 29,672 3,903 1916 122,236 8,759 56,341 2,520 Jan. 202,616 8,741 99,326 2,358 Feb. 131,591 9,344 4,593 2,520 Mar. 149,934 9,042 2,439 399 April 157,954 9,130 2,520 545 May 156,159 5,830 2,439 646 June 153,074 4,770 2,520 752 July 149,802 3,570 2,520 690 Aug. 146,592 2,810 2,439 525 &pt. 143,628 6,473 2,520 395 [Oct. 141,250 4,130 2,439 264 Nov. 138,547 5,253 21,173 2,520 Dec. Total or 77,852 181,433 29,754 4,216 average 29—52411 458 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam, 383 feet. Capacity of reservoir, 180.000 acre-feet Constant draft of 22 second-feet maintained, other drafts only Run-off at as required by reservoir operating diagram Year and month Flood control Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1917 Jan. 9,280 63,201 8,172 13,501 1,352 Feb. 13,200 49,456 7,551 1,222 Mar. 13,600 53,883 9,344 1,352 April 10,500 56,787 9,042 1,309 208 May 8,610 56,728 8,531 1,352 276 June 5,270 55,179 5,270 1,309 327 July 3,140 53,543 3,140 1,352 379 Aug. 2,200 51,812 2,200 1.352 345 Sept. ],5i9 50,115 1,510 1,309 262 Oct. 1,560 48,544 1,560 1,352 198 Nov. 1,840 46,994 1,840 1,309 127 Dec. 2,000 45,558 2,000 1,352 Total or average 72,710 60,160 13,501 15.922 2.122 1918 Jan. 2,020 44,206 2,020 1,352 Feb. 9,330 42,854 3,847 1,222 Mar. 73,200 47.115 9,249 3,595 1.352 April 17,000 106,119 9,042 1,309 315 May 10,000 112,453 8.993 1,352 436 June 6,010 111,672 6.010 1,309 514 July 3,970 109,849 3.970 1,352 601 Aug. 2,840 107,896 2,840 1,352 551 Sept. 2,330 105,993 2,330 1.309 420 Oct. 2,930 104,264 2,930 1,352 319 Nov. 3,140 102,593 3,140 1,309 212 Dec 4,370 101,072 4,370 27,459 1,352 Total or X Utdl Ul average 137,140 58,741 31,054 15,922 3,368 1919 Jan. 3.300 72,261 3,300 1,352 Feb. 4,110 70,909 4,110 1,222 Mar. 6,110 09.087 6,110 1,352 April 6,010 68.335 6,010 1,309 230 May 3,810 66,796 3,810 1,352 305 June 1,890 65,139 1,890 1,309 361 July 1,320 63,469 1,320 1,352 420 Aug. 935 61,697 935 1,352 385 Sept. 1,010 59,960 1,010 1,309 293 Oct. 2,040 .58,358 2,040 1,352 222 Nov. 2,130 56,784 2,130 1,309 143 Dec. 5,340 55.332 5,209 1.352 Total or average 38,005 37,874 15.922 2,359 1920 Jan. 3,260 54,111 3,260 1.352 Feb. 12,700 52,759 5,854 1.265 Mar. 30,200 58.340 9,344 1,352 April May 25,100 83,844 9,042 1,309 284 12,600 98,309 9,344 1,352 401 June 7,380 99,812 7,349 1,309 476 July 4,670 98,058 4,670 1,352 555 Aug. 3.200 96,151 3.200 1,352 512 Sept. 2,030 94,287 2,030 1,309 391 Oct. 2,000 92.587 2,000 1,352 295 Nov. 2,380 90.940 2,380 1,.309 194 Dec. Total or average 2,210 89.437 2,210 16.619 1,352 113,730 60,683 16.619 15,965 3,108 THE CONTROL OF FLOODS BY RESERVOIRS. 459 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY. tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam, 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operating diagram Flood control Year and month Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1917 123,201 8,172 12,270 2,520 Jan. 109,519 7,551 2,276 Feb. 112,892 9,344 2,520 Mar. 114,628 9,042 2,439 325 .^pril 113,322 8,531 2,520 432 May 110,449 5,270 2,439 508 June 107,502 3,140 2,520 589 July 104,393 2.200 2,520 539 Aug. 101,334 1,510 2,439 408 Sept. 98,487 1,560 2,520 305 Oct. 95,662 1.840 2,439 202 Nov. 93,021 2,000 2,520 Dec. Total or average 60,160 12,270 29,672 3,308 1918 90,501 2,020 2,520 Jan. 87,981 3,847 2,276 Feb. 91,188 9.249 2,520 Mar. 152,619 9,042 2,439 403 April 157,735 8,993 2,520 543 May 155,679 6,010 2,439 644 June 152,596 3,970 2,520 752 July 149,324 2,840 2,520 688 Aug. 146,116 2,330 2,439 525 Sept. 143,152 2,930 2,520 395 Oct. 140,237 3,140 2,439 262 Nov. 137,536 4,370 2,982 2,520 Dec. Total or average 58,741 2,982 29,672 4,212 1919 132,034 3,300 2,520 Jan. 129,514 4,110 2,276 Feb. 127,238 6,110 2,520 Mar. 124,718 6,010 2,439 341 April 121,938 3,810 2,520 454 May 118,964 1,890 2,439 533 June 115,992 1,320 2,520 621 July 112,851 935 2,520 567 Aug. 109,764 1.010 2,439 430 Sept 106,895 2,040 2,520 323 Oct. 104,052 2,130 2,439 212 Nov. 101,401 5,209 2,520 Dec. Total or 37,874 29,672 3,481 average 1920 99,012 3,260 2,520 .Jan. 96,492 5,854 2,358 Feb. 100,980 9,344 2,520 Mar. 125,316 9,042 2,4.39 361 April 138,574 9,344 2,520 ,500 May 138,810 7.349 2,439 .595 June 135,807 4,670 2,520 690 July 132,597 3,200 2,520 633 Aug. 129,444 2,030 2,439 480 Sept. 126,525 2,000 2,520 363 Oct. 123,642 2,380 2,439 238 Nov. 120,965 2,210 2,520 Dec. Total or 60,683 29,754 3,860 average 460 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Continued). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Computa (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- H eight of dam, 383 feet. Capacity of reservoir, 180,000 acre-feet Constant draft q f 22 second-feet maintained, other drafts only Run-off at aa required by reservoir operating diagram Year and 1 Flood control month Azusa in Stage of water passing Constant draft | acre-feet reservoir at Passed by Azusa during from over-year Evaporation Waste over beginning dam for flood season at storage from reservoir spillway of month in prior rights rates less than (22 second-feet) surface in acre-feet acre-feet in acre-feet 1.900 second- feet in acre-feet in acre-feet in acre-feet 1921 Jan. 5,160 71,466 4,405 18,459 1,352 Feb. 4,490 52,410 4,490 1,222 Mar. 15,400 51,188 7.288 1.352 April 6,070 57,948 6,070 1,309 206 May 15,700 56,433 6,835 1,352 282 June 8,980 63,664 7,920 1,309 361 July 3,830 63,054 3,830 1,352 418 Aug. 2,450 01,284 2,450 1.352 383 Sept. 1,840 59,549 1,840 1,309 293 Oct. 2,040 57,947 2,040 1,352 220 Nov. 1,800 56,375 1,800 1.309 143 Dec. 119,000 54,923 5,045 41,740 1,352 Total or average 186.760 54,013 60,199 15,922 2,306 1922 Jan. 62,100 125,786 9,344 107,332 1,352 Feb. 88,900 69,858 8,440 83,316 1,222 Mar. 47,800 65,780 9,344 2,882 1,352 April 31,400 100,002 9,042 1,309 317 May 24.700 120,734 9,344 1,352 474 June 14.400 134,264 9,042 1,309 591 July 9.100 137,722 • 8,576 1.352 700 Aug. 5,080 136,194 5,080 1.352 646 Sept. 3.290 134,196 3,290 1.309 496 Oct. 3,110 132,391 3,110 1,352 375 Nov. 5,310 130,664 4,519 25,655 1,309 242 Dec. 21,500 104,249 8.456 52.740 1.352 Total or average 316.690 87,587 271.925 15,922 3.841 1923 Jan. 7,130 63,201 6.968 12.056 1.352 Feb. 7,830 49,955 7,791 1.222 Mar. 7,320 48,772 7,320 1,352 April May 8,330 47,420 8,079 1,309 182 5,480 46.180 5.480 1.352 244 June 3.700 44,584 3.700 1.309 288 July 2.420 42,987 2.420 1.352 331 Aug. 1,990 41.304 1.990 1.352 299 Sept. 1,750 39.653 1,750 1.309 232 Oct. 1.710 38,112 1,710 1.352 171 Nov. 1.960 36,589 1.960 1.309 111 Dec. 2,130 35,169 2,130 1.352 Total or average 61.750 51,298 13,056 15.922 1,858 1924 Jan. 2,170 33,817 2.170 1.352 Feb. 1.790 32.405 1,790 1,265 Mar. 4.130 31.200 3.714 1.352 April May 6,190 30.264 6,190 1.309 141 3,650 28,814 3.650 1,352 186 June 1,660 27,276 1.660 1.309 214 July 1.000 25.753 1.000 1.352 248 Aug. 756 24,153 756 1,352 222 Sept. 744 22,579 744 1,309 167 Oct. 873 21,103 873 1,352 123 Nov. 1.190 19,628 1.190 1.309 79 Dec. Total or 1.780 18,240 1,780 1.352 average 25.933 25.517 15.965 1,380 THE CONTROL OF FLOODS BY RESERVOIRS. 461 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam , 425 feet. Capacity of reservoir, 240.000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operatng diagra m Flood control Year and Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Aziisa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from r«eervoir surface in acre-feet Waste over spillway in acre-feet month 1921 118,445 4,405 4,431 2,520 Jan. 112,249 4,490 2,276 Feb. 109,973 7,288 2,520 Mar. 115,565 6,070 2,439 325 April 112,801 6,835 2,520 436 May 118,710 7,920 2,439 533 June 116,798 3,830 2,520 623 July 113,655 2,450 2,520 569 Aug. 110,566 1,840 2,439 432 Sept. 107,695 2,040 2,520 325 Oct. 104,850 1,800 2,439 214 Nov. 102,197 5,045 31,012 2,520 Dec. Total or average 54,013 35,443 29,672 3,457 1922 182,620 9,344 105,595 2,520 Jan. 127,261 8,440 79,666 2,276 Feb. 125,779 9,344 2,562 2,520 Mar. 159,153 9,042 2,439 424 April 178,648 9,344 2,520 611 May 190,873 9,042 2,439 752 June 193,040 8,576 2,520 894 July 190,150 5,080 2,520 815 Aug. 186,815 3,290 2,439 623 Sept. 183,753 3,110 2,520 470 Oct. 180,763 4,519 14,559 2,439 307 Nov. 164,249 8,456 51,572 2,520 Dec. Total or average 87,587 253,954 29,672 4,896 1923 123,201 6,968 10,928 2,520 Jan. 109,915 7,791 2,276 Feb. 107,678 7,320 2,520 Mar. 105,158 8,079 2,439 305 April 102,665 5,480 2,520 403 May 99,742 3,700 2,439 474 June 96,829 2,420 2,520 549 July 93,760 1,990 2,520 500 Aug. 90,740 1,750 2,439 379 Sept. 87,922 1,710 2,520 288 Oct. 85,114 1,960 2,439 186 Nov. 82,489 2,130 2,520 Dec. Total or average 51,298 10,928 29,672 3,084 1924 79,969 2,170 2,520 Jan. 77,449 1,790 2,358 Feb. 75,091 3,714 2,520 Mar. 72,987 6,190 2,439 238 April 70,310 3,650 2,520 315 May 67,475 1.660 2,439 369 June 64,667 1.000 2,520 426 July 61,721 756 2,520 385 Aug. 58,816 744 2,439 290 Sept. 56.087 873 2,520 214 Oct. 53.353 1.190 2,439 139 Nov. 60.775 1.780 2,520 Dec. Total or average 25,517 29,754 2,376 462 WATER RESOURCES OF CALIFORNIA. TABLE 17a (Concluded). SAN GABRIEL COMPARISON OF WATER YIELD FOR FOR FLOOD CONTROL AND Monthly Summary of Compute (For corresponding yearly sum Maximum controlled flow at Azusa 1,900 second-feet. Natural flow up to 152 second- Height of dam, 383 feet. Capacity of reservoir, 180,000 acre-feet Constant draft of 22 second-feet maintained, other drafts only Run-off at as required by reservoir operating diagram Year and month Flood control Azusa in acre-feet Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in Constant draft from over-year storage (22seoond-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet acre-feet 1925 Jan. 1,710 16,888 1,710 1,352 , Feb. 1,620 15,536 1,620 1,222 Mar. 2,510 14,314 2,423 1,352 April 7,200 13,049 5,765 1,309 89 May 3,050 13,086 3,050 1,352 105 June 1,840 11,629 1,840 1,309 131 July 824 10,189 824 1,352 141 Aug. 621 8,696 621 1,352 117 Sept. 492 7,227 492 1,309 81 Oct. 87.S 5,837 873 1,352 52 Nov. 1,010 4,433 1,010 1,309 28 Dec. 1,650 3,096 1,650 1,352 Total or average 23,400 21,878 15,922 744 192S Jan. 1,540 1,744 1,540 1,352 Feb. 7,940 392 5,485 1,222 Mar. 3,650 1,625 3,650 1,352 April 69,000 273 8,233 1,309 159 May 13,000 59,572 9,142 1,352 293 June 5,500 61,785 5,500 1,309 349 July 3,120 60,127 3,120 1,352 408 Aug. 2,070 58,367 2,070 1,352 373 Sept. 1,580 56,642 1.580 1.309 284 Oct. 55,049 Nov. Dec. Total or average 107,400 40,320 11,909 1,866 Total for period, Jan. 1, 1897, to Oct. 1, 1926 3,731,977 1,513,303 "1,672,152 473.905 76,867 3,351 Average for period. Jan. 1, 1897, to Oct. 1, 1926 125,445 50,867 "56,207 1 15,930 2.584 113 • These Bgures contain 7601 acre-feet total or an average of 256 acre-feet per season of water contributed from outside the exact period of analysis. In the computations from which this table is prepared, the water in storage is less by this amount than on January 1, 1897, the beginning of the period. Since in the comput'.ilions this water was released as flood control water during the first flood season of the period, the exact yield of flood control water for the period is less than here shown by this amount. THE CONTROL OF FLOODS BY RESERVOIRS. 463 RESERVOIR ON SAN GABRIEL RIVER. TWO SIZES OF RESERVOIR OPERATING CONSTANT DRAFT ONLY, tions Carried out on a Daily Basis. mary, see Table 17, page 184.) Maximum flood control reserve 131,000 acre-feet, feet passed for prior rights. Height of dam 425 feet. Capacity of reservoir, 240,000 acre-feet Constant draft of 41 second-feet maintained, other drafts only as required by reservoir operating diagra m Flood control Year and Stage of reservoir at beginning of month in acre-feet Passed by dam for prior rights in acre-feet water passing Azusa during flood season at rates less than 1,900 second- feet in acre-feet Constant draft from over-year storage (41 second-feet) in acre-feet Evaporation from reservoir surface in acre-feet Waste over spillway in acre-feet month 1925 48,255 1,710 2,520 Jan. 45,735 1,620 2,276 Feb. 43,459 2,423 2,520 Mar. 41,026 5,765 2,439 171 April 39,851 3,050 2,520 222 May 37,109 1.840 2,439 254 June 34,416 824 2,520 288 July 31,608 621 2,520 256 Aug. 28,832 492 2,439 188 Sept. 26,205 873 2,520 137 Oct. 23,548 1,010 2,439 85 Nov. 21,024 1,650 2,520 Dec. Total or 21,878 29,672 1,601 average 1923 18,504 1,540 2,520 Jan. 15,984 5,485 2,276 Feb. 16,163 3,650 2,520 Mar. 13,643 8,233 2,439 196 April 71,775 9,142 2,520 325 May 72,788 5,500 2,439 385 June 69,964 3,120 2,520 442 July 67,002 2,070 2,520 403 Aug. 64,079 1,580 2,439 303 Sept. 61,337 Oct. Nov. Dec. Total or 40,320 22,193 2,054 average Total for period, Jan.l, 1897, to Oct. 1, 1,513,303 1-1,297,000 i>883,173 99,814 1926 Average for period, June 1, 1897, to Oct. 1, 50,867 1^43,597 ''29,686 3,355 1926 •> These figures contain 61 ,313 acre-feet total or an average of 2060 acre-feet per season of water contributed from outside the exact period of analysis. In the computations from which this table is prepared the water in storage on October 1. 1926, the end of the period, is less by this aomunt than on January 1, 18!J7, the beginning of the period. A supplementary analysis, having the same amount of water in storage at the beginning and at the end of the period was made to obtain the exact yield for the period. This gave 47,900 and 23,300 acre-feet per season respectively for the flood control water and uniformly con- continuous flow instead of 43,597 and 29,686 acre-feet respectively that are shown herein. 52411 10-28 5M THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW \ AN INITIAL FINE OP 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO 50 CENTS ON THE FOURTH DAY AND TO $1.00 ON THE SEVENTH DAY OVERDUE. '»fe^- JAW UCD LIBRARY DUE SEP )i 9 1971 -'AN^ 5 1972 lORECu SF^^ RECEIVEC ^^y ZH 1986 •HV3 sC) UBRARY Book Slip-25m-7,'53(A899884)45r da//'/" PHYSICAL SCIENCES li3RARY 3 1175 00827 9583 l-lbKAKl UiaVKRSITY OF CALIFORNtA DAVI3 111584