AGRIC. PERT. 
 
 
REPORT 
 
 Board of Directors of Drainage District No, 1 
 
 PROGRESS OF WORK TO JANUARY 1, 1881. 
 

 
 AGRIC, DEPT. 
 
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REPORT. 
 
 OFFICE OF DRAINAGE DISTRICT No. 1, \ 
 
 SACRAMENTO, December 20th, 1880. j 
 
 1o his Excellency GEO. C. PERKINS, Governor of the State of California: 
 
 In compliance with the provisions of section four of an Act of the 
 Legislature of the State of California, entitled "An Act to promote 
 drainage," approved April twenty-third, eighteen hundred and 
 eighty, the Board of Directors of Drainage District No. 1 respectfully 
 submit to your Excellency a report of their proceedings by virtue 
 of the powers conferred upon them, including the amount of work 
 performed and the amount of money expended. 
 
 Drainage District No. 1 embraces practically all of that portion of 
 the State' of California drained by the Sacramento Kiver and its 
 tributaries. 
 
 The seventh section of the Act to promote drainage, provides that 
 " after the formation of any territory into a drainage district, the 
 State Engineer, as soon as practicable, after proper surveys have been 
 made, shall submit to the Board of Directors of the district, plans, 
 specifications, and estimates of the cost of the works necessary in said 
 district, in order to secure a proper system of drainage therefor." 
 
 After the report of the State Engineer; as aforesaid, is made, the 
 Board is requested to adopt, amend, or reject the whole or any 
 portion of the plans presented, or to refer them back to the State 
 Engineer for further report. After the adoption of plans and speci- 
 fications, the Board is required to advertise for thirty days for pro- 
 posals before any contract for work embraced in the plans can be 
 let. This Board was appointed on the tenth day of June of the cur- 
 rent year. The area of the district being so great, the magnitude of 
 the interests involved so stupendous, and the labor to be performed 
 by the State Engineer so extensive, that although the utmost 
 diligence was exercised by that officer and his assistants, the plans 
 and specifications could not be completed so as to enable us to 
 let contracts prior to the tenth day of August. 
 
 The following reports of Wm. Ham. Hall, State Engineer and 
 furnishing the basis of our actions will, we think, convey an ade- 
 quate idea of the problem to be solved. 
 
 THE WORKS OF DRAINAGE FOR THE SACRAMENTO VALLEY. 
 
 SACRAMENTO, June 25th, 1880. 
 Honorable Board of Directors, Drainage District No. 1 : 
 
 GENTLEMEN : You have been called upon to carry forward such works of drainage as may be 
 practicable and deemed necessary for the territory now known as Drainage District No. 1 , and 
 I, as State Engineer, am required to proposeplans for and supervise the execution of these works. 
 
The report to the State Drainage Commission. 
 
 The circumstances and views which have led to and governed in the formation of this district, 
 are set forth in a report made by myself to the State Board of Drainage Commissioners, under 
 date of May twenty-sixth, eighteen hundred and eighty, and which has been published, together 
 with a copy of the record of the minutes of the proceedings of that Board, had at a meeting 
 held on the twenty-eighth of May. 
 
 Drainage District -ZVb. 1. 
 
 Your district embraces all of the Sacramento Valley in which it will be necessary, as far as 
 can now be seen, to execute works of drainage, except some of the low lands in the delta which 
 is common to the San Joaquin as well as the Sacramento Kiver. 
 
 The report to the Legislature. 
 
 In a general way, the drainage of this district the Sacramento Valley has been discussed 
 by me in Parts II and III of my report to the Legislature, under date of January tenth, eight- 
 een hundred and eighty. To avoid much repetition of argument in detail, I shall herein only 
 briefly summarize the practical conclusions at large on this topic, and ask your attention to the 
 papers referred to, for the discussions which have led to them. The broad 'facts in the case are 
 as follows : 
 
 Facts concerning the rivers. 
 
 First Generally, throughout its course, the channel of the Sacramento Eiver as the main 
 drain, and that of the Feather as its chief auxiliary, in their present condition, are incapable of 
 affording passage for the waters of ordinary flood volume without subjecting a large portion of 
 the great low-land basins and island swamps to inundation. 
 
 Second The regimen of the Sacramento River is bad j its channel is of very uneven capacity 
 in proportion to the demand for waterway, in the succeeding great divisions thereof, besides 
 having serious local obstructions to flood flow. 
 
 Third These defects, general and local, have, in a degree, always existed, but they have 
 been largely developed of late years from causes still present or at work. The detritus from the 
 mines is filling the lower Sacramento River and its principal tributaries, and an injudicious 
 location of levees has unduly limited the width of flood waterway at important points and for 
 long stretches of channel. 
 
 Preservation of the rivers. 
 
 It is desired to preserve these river channels. By the passage of the law under which we are 
 called upon to act, the State has signified her realization of the importance of thus fostering the 
 interests more directly affected by their deterioration, as well as those dependent upon the 
 causes which in great measure produce this result. 
 
 The Act to promote drainage. 
 
 It is the object, as I understand the measure, to promote drainage as the title of the Act 
 implies in accomplishing which it is necessary to do away, as far as possible, with the evil 
 results of the flow of detritus from the mines, and to construct or develop waterway for the 
 Hoods. Furthermore, it is expected that the accomplishment of this end will improve the nav- 
 igation of the rivers and will facilitate the reclamation of swamp lands in the valleys adjacent, 
 because it would be impossible to attain the primary object without doing much which will 
 tend towards those kindred thereto. 
 
 GENERAL DRAINAGE PLANS. 
 
 Two general lines of action for the engineering solution of the river problems presented are 
 frequently brought forward. They rest respectively upon what may be termed the Conserva- 
 tion and the Distribution theories of river improvement. 
 
 The Outlet or Distribution treatment. 
 
 To carry aivay the waters of flood, it has been proposed to supplement the river waterway by 
 the construction of an artificial channel, or channels, on the route down the valley to the bay, 
 thus effecting a division of the waters, and, according to the arguments of the advocates of this 
 plan, producing a lowering of flood elevations and a shortening of high water periods. This is 
 the plan, based upon the theory that the greater number of channels in which the waters run, 
 the less will be their flood elevations a theory which I have called the Distribution theory, 
 because of the distribution of the waters amongst several channels. 
 
 In the report spoken of, I have discussed this plan of outlet canals, and have expressed the 
 opinion that it would not afford the desired relief from excessive flood heights, but, on the con- 
 trary, its primary result would be to bring about a further deterioration of the channel of the 
 main river and impair its usefulness as a flood-carrying and navigable stream. I am led to this 
 conclusion by the results of experience had in river improvement -re, the records of 
 
which I have examined, and by the behavior of this stream itself under conditions observed 
 during the past two years. 
 
 The conclusion rests upon the opinion now quite generally entertained by engineers, and 
 based upon practical observation as well as sound principles, that the division of the waters of 
 a sediment-bearing river results in the formation of bars in the channel below the points of 
 diversion, and ultimately in the permanent contraction of the waterway in the proportion 
 which the volume of water diverted bears to the volume formerly carried by the channel. 
 The only exception to this rule is to be found within the influence of heavy tidal action, and 
 where other conditions are present favorable to the tidal influence. 
 
 The Conservation treatment. 
 
 Holding this opinion, I have recommended the alternative course a systematic treatment of 
 the river channel itself throughout, with the view of developing its greatest possible carrying 
 capacity, and of maintaining it in good navigable condition. This plan rests upon the idea that 
 the greater the volume of water in a channel, the less may be, and generally is, its grade or 
 slope, and hence a conservation of waters in a channel having a movable bottom will tend to 
 reduce its slope and lower its flood elevations by scouring out the bottom material. This I have 
 called the Conservation theory of river improvement. 
 
 The lower Sacramento River and its principal tributary, the Feather, have beds most readily 
 moved by the action of the current, and the upper Sacramento has a channel which can be 
 greatly improved by work hereafter to be discussed. Hence I have expressed the opinion, after 
 an examination and measurement in detail, that their development can be carried forward to a 
 stage at which capacity would be afforded for the passage of all ordinary floods ; but I have said 
 that the work must be one for a series of years, and that from the first, the great supplies of 
 sand which are brought down the mining torrents, must be prevented from entering the larger 
 streams of the valley. 
 
 A general plan of operations, according to the Conservation treatment, was sketched out in 
 the report to the Legislature, heretofore spoken of, and it remains now to classify and mention 
 the principal works which it will be necessary to prosecute, and this I now do, so far as these 
 can be designated at present. 
 
 Some provisions in the law. 
 
 In classifying and pointing out the works which may be carried forward under your direction, 
 I hold in view the provision of the law which stipulates that " all moneys raised * # * 
 shall be used exclusively for the construction of dams for impounding the debris from the 
 mines, * * * and for the rectification of river channels in which said debris flows within 
 the drainage district," etc. (Sec. 24.) 
 
 This stipulation would seem to preclude the construction of any such work as a relief canal, 
 and the building of levees for the protection of lands from inundations, but it does not prohibit 
 the prosecution of any work which may be necessary for the impounding of debris or the recti- 
 fication of river channels in which the debris flows. I hold that the works hereinafter desig- 
 nated are necessary to effect these ends, within the district whose drainage system you are called 
 up on to improve, as I will endeavor to show in each case. 
 
 CLASSIFICATION OF WORKS. 
 
 Two general classes of works must be undertaken: the first, to withhold the sands from the 
 main stream and private property; the second, to improve the channels of those streams so that 
 they will maintain themselves, with a small amount of attention, subsequently, in the best 
 possible condition, as flood-carrying and navigable channels. These works may be somewhat 
 more definitely classified as follows : 
 
 Arresting the flow of the detritus dams. 
 
 First Works calculated to check the flow of sands into the navigable rivers from the mining 
 streams. These will consist of dams composed of rough stone, brushwood, and gravel, or a 
 combination of these materials, as the case may be, located and proportioned as may seem most 
 favorable in each case. 
 
 Structures of this character should first be projected where the best conditions are presented 
 for the test of their efficiency at a reasonable outlay oi money. Other things being equal, the 
 lower down such works can be brought on the tributary streams, the more certain they will be 
 of accomplishing their object, and at small outlay of money; for lighter grades are found upon 
 which to impound or rest the materials stored, longer crested dams are possible (over which the 
 water will pour to a less depth and with less force) and less material will be left below the site 
 unguarded or unrestrained. 
 
 The Yuba and the Bear Eivers present the best opportunities for this class of work, and the 
 localities where it is most needed. 
 
 In a special report to be submitted concerning each of these streams, I will make recom- 
 mendations and submit plans for the works which I deem advisable to undertake at once upon 
 them. 
 
Preventing the spread of the detritus levees. 
 
 Second Works calculated to guard against the spread of the waters from the mining streams, 
 and consequent destruction of the channels in which they flow. 
 
 These Avill consist of levees, and those already in existence should be strengthened, r 
 or protected from erosion, as may be necessary in each case, or new levees may be constructed 
 where none are now in existence or the old ones are not worth adhering to. 
 
 The law provides that such works as are necessary for the rectification of the river channels 
 in which said debris flows, may be constructed. Levees on each side of such streams as the 
 Yuba and Bear Rivers, for instance, may be necessary to prevent the spread of their waters. 
 Xo\v the spreading of these waters results in the deposit of their sediment and the obliteration 
 of the river channels. It is necessary, therefore, in order to rectify these channels, that the 
 - be not allowed to spread, hence levees are necessary; and hence, I presume, you will 
 undertake this class of work. 
 
 Again, the Yuba and Bear River regions present the theater of most needed action, though 
 alon-- the shores of the Feather, also, as well as on the lower course of the American, existing 
 levees must be maintained, if proper control is to be exercised over their waters, and the river 
 channels preserved or improved. In a special report concerning work which should be under- 
 taken this season, I will speak more definitely of this subject. 
 
 Checking the shoaling of the main rivers. 
 
 Third Works calculated to guard against the further deterioration of the channels of the 
 larger rivers, and exert an influence towards their complete rectification. 
 
 These will have for their immediate objects, (1st), the prevention of heavy bank caving, except 
 where such may be desirable to effect some beneficial change in the stream alignment : and (2d), 
 the closing, or partial closing, of all deep channels of escape for water from the main stream 
 (such as the crevasses through the bank of the Sacramento River below Knight's Landing to 
 Sacramento City), so far as these can be closed without causing other ruptures and the creation 
 of other, lines of overflow. 
 
 Bank caving spur dikes and revetement. 
 
 The first one of the objects just mentioned, is to be attained by the construction of spur dikes 
 of brush, stone, gravel, sand-boxes, or piling, or a combination of some of these, to deflect the 
 current from the bank attacked, and create deposits for new bank lines. The Sacramento River 
 above Colusa presents the field where it will be most necessary to conduct this class of work, for 
 there are a number of points where the river channel is of exceedingly bad trend, owing to this 
 caving of banks, and radical changes of the channel are threatened to the detriment of its uni- 
 form regimen as a whole, and consequent defeat of its rectifications a leading object of the 
 whole measure. 
 
 Deep outlets gradual closure, overfloiv weir*. 
 
 The second object of this class of work is to be attained by entirely closing the breaks in 
 existing levees, so far as it is safe so to do, with earth embankments, and by partially closing 
 the remaining openings the deeper cuts, at least with structures of brush, timber, and gravel 
 or stone, over which the water may pour, when it reaches a certain safe flood elevation, without 
 damage to the structure itself. 
 
 I consider these overflow weirs an essential feature of the plan of improvement proposed, for 
 the river from Knight's Landing to Sacramento City, and it may be necessary to apply them 
 elsewhere along its course also. If there were means enough at command to construct at once 
 such strong and large levees along the river, and to do such other work as would facilitate it- 
 scouring out and rectification, by the holding of all flood water, then the weirs might be dis- 
 i with. But this would necessitate an outlay beyond the means at all likely to be at your 
 disposal, and as the water will undoubtedly escape during floods at various points for some time 
 to come, I propose that it shall find passage at such points and in such manner as will do least 
 harm, and only at such times as the river channel may not be able to carry all presented to it. 
 
 Concerning the extent of this class of work to be done, the location and character of construc- 
 tion for the proposed weirs, I will shortly submit a special report for your consideration. 
 
 Promoting the deepening of the main rivers. 
 
 Fourth Works calculated to cause the removal of bars in the river, where they exercise an 
 unfavorable influence upon the uniformity of its capacity, and thus prevent general deepening 
 by the scouring action of its current. 
 
 Several notable bars of this character and effect exist in the Sacramento River below the 
 mouth of the J-Y;ither, and they are found, as is usual in such cases, where the bank lines are 
 far apart, or where some irregularities of alignment in the banks exist and cause a check or 
 eddy in the current and a deposit of sand as a result. 
 
 Removal of bars spur dikes, parallel dikes. 
 
 Their removal is to be accomplished by the construction of spur dikes, or perhaps similar 
 works parallel to the current according to the circumstances in each case of brush, stone, 
 
gravel, or timber piling, or a combination of these, in such manner as to cause a concentration 
 of the current upon a judicious alignment, by contracting the channel to its normal width, 
 and guiding the water in such narrowed channel up to an elevation equivalent to a low flood 
 .stage. 
 
 I may say here, by way of parenthesis, that dredging may be required in some of the bars, 
 but this result is not expected generally. 
 
 As in the case of the last mentioned class of works, these constitute, in my opinion at least, 
 a most important feature in the plans to rectify the channel of the river, and, as their position 
 in this enumeration implies, should be carried forward before the final and completed effort is 
 made to force scouring action by altogether confining the flood waters ; because a condition of 
 channel approximating a perfect regimen for the river is essential to success in confining its 
 flood waters, and to approach such a condition local obstructions must be removed. 
 
 Correcting the alignment of the main rivers. 
 
 Fifth Works calculated to straighten the river channel where, by reason of sudden and 
 irregular turns or bends, a serious check is given to flood movements, and where the slope or 
 grade of the country is less than that through which the river generally courses. 
 
 Under the proper circumstances a channel may be benefited in this way by making sudden 
 and sharp bends less abrupt and angular, or by opening a new channel through behind such a 
 sinuosity of the river course, which latter works are termed cut-offs. 
 
 Where a bend is very abrupt it may be made less so. Training the current against it by the 
 use of spur dikes constructed on the opposite shore above, crowding the current out of the 
 opposite bay by the continuation of the series of spur dikes from above down into it, and blow- 
 ing down the point from time to time to be washed away, as may be necessary, will accomplish 
 this result. 
 
 Cid-offs Upper Sacramento River. 
 
 To cause the complete elimination of a bend from the course of the channel, cut-offs are 
 made by clearing the path of the proposed new channel, cutting out a canal down to near low 
 water mark upon its route, to a width of one tenth to one fifth that of the proposed channel, 
 and forcing the currents of floods to enter the cut by a proper arrangement of spur dikes or 
 other guiding works if it be necessary, and from time to time gradually closing the old channel 
 as the new one becomes efficient by washing out. 
 
 The Sacramento River, between Colusa and Butte Slough and the mouth of Feather River, is 
 a very tortuous stream, and narrow in proportion to its dimensions above and below. The 
 grade of the country through which it flows for this division is much less than that above. Its 
 capacity is much less than that of the divisions above and below under existing circumstances, 
 and this is largely occasioned by excessive bend resistance due to the sudden turns in its chan- 
 nel and general tortuous course. 
 
 To bring the river to a good regimen it will be necessary, in my opinion, to diminish the 
 abruptness of the most acute turns in this part of the channel, and shorten it also, by making 
 some cut-offs. These can be carried out at a reasonable outlay of money, in a number of 
 instances. 
 
 Prevention of cut-offs Upper Sacramento River. 
 
 While it is necessary that the river's course should be straightened through the divisions from 
 Butte Slough to the mouth of Feather, I hold that above Butte Slough, where the formation of 
 cut-offs is most easy, and where they do occur naturally sometimes, all straightening of the 
 channel should be prevented, because the river is already of much greater grade and cross sec- 
 tional dimensions than it is in the division^iext below, where it is necessary, by making cuts 
 and the other works spoken of, to increajjBp^ carrying capacity and thus accommodate the 
 floods which are passed through the channdl'kbove. 
 
 Cut-offs Lower Sacramento River. 
 
 Besides the points in the division mentioned from Butte Slough to Feather River, the only 
 other locality where the cut-off treatment is admissible on the Sacramento River, is at the upper 
 end of Steamboat Slough, where it is desirable to open up a new head for that channel, in the 
 process of making it the principal line of escape for the flood waters. This subject is quite fully 
 discussed in my report to the Legislature, and I will not say more upon it until I present the 
 details in a special paper. 
 
 Forcing the scouring and enlargement of the main rivers. 
 
 Sixth Works calculated to confine the waters of the river to its channel and cause an enlarge- 
 ment thereof by the scouring action thus brought about. 
 
 _ These works, of course, are levees, a complete system of which, from the highest point on the 
 river where its waters escape into the back basins to the point where full tidal action is met at 
 the foot of Grand Island, is essential, in my opinion, to success in the work of rectifying its 
 channel and its final maintenance in an efficient and serviceable condition as a line of flood 
 escape and a navigable thoroughfare. 
 
Concentration of icaters. 
 
 That the concentration and deepening of running water does increase its power to transport 
 sediment, and thus bring about an enlargement of its channel, if the bed and banks thereof ;i re 
 of a character to be at all readily moved, engineers and others who study such matters are well 
 agreed. 
 
 The confining of a greater body of water over the bed of the Sacramento River will undoubt- 
 edly cause its enlargement by the process referred to: and if local obstructions are removed in 
 the manner heretofore spoken of or in any manner which may be necessary, this enlargement 
 will go on so long as the waters are held in and the bottom is found to be of the character 
 known to exist generally throughout the lower river, until the stream is much increased over 
 its present dimensions: fii-oridc'l . that the extraordinary flow of sands by which the waters are 
 now overloaded is checked in the mining tributaries. 
 
 The levee system. 
 
 It is frequently urged in argument against the levee system of river improvement, that the 
 prevention of overflow causes the rapid elevations of the stream's bed as compared to the banks 
 and back lands upon which the waters are prevented from spreading their sediments, and thus 
 finally results in the overthrow of the levees, destruction of the lands, and injury to the river 
 itself. 
 
 Although in the course of ages this result might, under the natural order of things, have 
 been brought about by leveeing the Sacramento River, it is certainly a question of much less 
 time, under existing circumstances, when the channel below the mouth of Feather River will 
 be destroyed, if the whole river is not treated by the levee system ; and as for the back lands,, 
 they can be no worse off than they are now in any event. 
 
 Deterioration of the Sacramento River. 
 
 This river channel is being destroyed by the sands which are rolled along its bottom, not by 
 the fine sediments which are carried in suspension by its waters, and which only would be 
 carried in large quantities out of it upon the back lands, if the levee Avere obliterated. 
 
 The escape of waters from the channel would not relieve it from the charge of solid matter 
 which it annually receives, but would simply cause the permanent lodgment of that matter 
 therein, whereas, by the confinement of its waters alone can the conditions be produced under 
 which this detritus may be carried forward to the flats and marshes of Suisun Bay, where it 
 will do less harm, for many years to come, than where it is lodging now. 
 
 We have had the low-water plane of this river raised two, three, four, and even five feet 
 during the past twenty years. Such a rapid change was never heard of before in the history of 
 other large rivers, and where the levee system, too, had equal scope for action. The bed of the 
 Po, a river completely leveed, and whose waters are highly charged with sediment, has not been 
 raised so much during the period of its recorded history. The levees of the Po may have 
 caused a relative rise of several feet in its bed over that of its banks during the past two- 
 centuries, and so the levees of the Sacramento may ultimately have that effect. But the first 
 effect of a complete levee system on this river, when it is brought to a good regimen and the 
 flow of sands stopped, will be to cause a great scouring out of its bed and enlargement of its 
 channel, and thus lower both its flood and low water planes, and many years will elapse before 
 the effect of the levees in causing a contrary action will be felt. 
 
 The Mississippi and the Sacramento. 
 
 A river such as the Mississippi, whose great defect in capacity is due to the very shoal bars 
 caused by caving banks and great irregulari^Hkwidth, can have its wateiiine sufficiently 
 lowered by the simple scouring out of these slxWfiWTO carry its floods between banks without a 
 levee system as a necessary part of the plan, 
 
 Not so. however, with the Sacramento. We must remember that such is not the principal 
 cause of deficient capacity in our river. Its banks arc quite stable where the capacity is small : 
 but few shoals exist to be removed, and these, although their continued presence wolild prevent 
 a general improvement of the channel, are not themselves the principal cause of its inefiiciency. 
 
 The Mississippi River, with a flood discharge of one million two hundred thousand to one 
 million four hundred thousand cubic feet per second due to it, carries over or in its main bed 
 from five sixths to nine tenths of its waters, losing one sixth to one tenth only into tin- swamps 
 at high flood stage. 
 
 The Sacramento River, between Butte Slough and the mouth of Feather River, with a flood 
 discharge of eighty thousand cubic feet per second due to it, carries through only thirty thou- 
 sand, having lo.-t. into the back basins on its course nearly two thirds of its waters. There is 
 no considerable obstruction to flood flow from shoals in this part of the river. The channel is 
 narrow, has firm banks, and is exceedingly crooked. 
 
 The floods rise to their maximum height in the upper portion of this division next below 
 Butte Slough, and overtop levees three or four feet in height before the water is bank high at 
 Knight's Landing, twenty or thirty miles below. 
 
Defects of the Sacramento River. 
 
 As before remarked, these divisions of the Sacramento River from Butte Slough to the 
 month of Feather River are in need of something more than the sweeping out of shoals. The 
 channel must be straightened and heavily leveed to facilitate and force its enlargement 
 throughout. 
 
 This river is naturally too small for the amount of water that is presented to it generally 
 throughout its course, because, for ages past, so large a portion of its volume, at time of flood, 
 has, from local causes, escaped into the back basins,, that the channel way has become con- 
 tracted. 'The proof of this action is found in the fact that below every escape channel of note, 
 all along its course, there is a radical diminution of average cross sectional area; and further- 
 more, as the water has escaped gradually over the banks all along, there is a gradual diminu- 
 tion in width found in going down stream through each grand division of the river, from one 
 large outlet or tributary to the next below, until we arrive at the region below Grand Island, 
 where the tide has full sway and its flow regulates, in a great measure, the width and depth. 
 
 The popular idea of filling the low basins. 
 
 We have frequently heard that the Sacramento River should be allowed to overflow its banks 
 so that the low basins might become filled up. It may be remarked here, with propriety, that 
 these basins would not fill up unless the river deserted its present course and occupied them in 
 turn as channel ways. The river bed and its immediate banks were, naturally built higher 
 than the basins before the advance of the sands from the mines, and they would probably con- 
 tinue to rise more rapidly than the basins, for the sediments brought down by the waters of 
 such streams are, for the most part, deposited immediately on the bank which is naturally 
 overflowed, and it is only when'the waters escape with force through a crevasse that the solid 
 matter is carried far back into the basin and elevates it commensurate with the rate of eleva- 
 tion of the river bank and bed. 
 
 The true idea of this matter. 
 
 Thus the only way to equalize the land elevation back from the river to that along its bank 
 would have been to levee the river and force streams of water back to the basin through chan- 
 nels, and there cause the deposit of their sediments. 
 
 But as the river has received this charge of sand, which cannot thus be sluiced out on to the 
 low lands, to any great extent at least, and as the preservation of the river is the object in view 
 and not the filling up of the basins, there is still greater necessity now for a complete confine- 
 ment of the waters between levees. 
 
 I refer in the above to the Sacramento River below the mouth of the Feather, and presume 
 that the object is to preserve and improve its channel. That this river itself could be turned 
 into the basin which flanks it on the west, and' there be made to deposit its sediment for some 
 years to come, is quite certain; but the result would be destruction to the present channel, 
 and the future would be altogether problematical with the land and cities below the point of 
 turning. 
 
 Necessity for a levee system on the Sacramento and Feather Rivers. 
 
 After the other works which have been hereinbefore spoken of have been well taken in hand, 
 the general leveeing of the river should begin. This work should be prosecuted from the upper 
 portion of the stream downwards, in the reverse direction from that of the other principal 
 improvements. The channel itself should be cleared of local obstructions from the lower end 
 up, to bring about the conditions under which it will profit by the effects of leveeing and con- 
 fining its waters, and then this forcing should commence at the upper end. 
 
 The first leveeing that is undertaken, therefore, other than that necessary to equalize banks 
 along the river generally and close gaps as before explained, should be from Chico Creek to 
 Butte Slough. 
 
 In my report to the Legislature, already referred to, will be found some general suggestions 
 for the disposition of the levees along this part of the river as well as through other divisions. 
 In special reports on the subject, hereafter to be submitted, the matter will be treated more in 
 detail. 
 
 OTHER "WORKS. 
 
 I have now classified the works which it is essential should be carried forward for the rectifi- 
 cation of the main rivers of this valley, and have inu ; cated, in a general way, the localities 
 where they are to be undertaken, and the*order of their proper progress. 
 
 In addition to these it may be necessary, as time goes on, to execute other works, some of 
 them of considerable magnitude, in order to relieve the large rivers of the load of silt which is 
 brought to them, and insure their continued improvement, as well as to otherwise dispose of 
 flood waters, if the drainage of the valley is to be'made complete. 
 
 Diversion of tributaries to deposit detritus. 
 
 For instance, although the Sacramento River itself cannot with propriety and safety be 
 turned into any of the low basins which flank it, as a means of disposing of the sands, the case 
 
10 
 
 may be different with several of its tributaries, notably the American and the Bear Rivers, which 
 be led to deposit their .-unds in the low basin lying between the two on the cast side of 
 raiiic'.ito. Indeed, they both do so now in a degree, and during the past season the Bear 
 has shown a strong di.-p<siiion to turn to the south altogether and desert its former mouth 
 
 into the Feather for an outlet into the basin mentioned. 
 
 An examination in detail of the practicability and cost of thus disposing of the sands of these 
 
 two troublesome tributaries will be made under my direction during the present season, and 
 
 will form the subject of a special report at a later date. 
 
 of the Coast Range Creek flood waters. 
 
 And still again, the disposal of the waters of Putah and Cache Creeks, which flow into the 
 Yolo basin, is an essential part of a complete system of drainage for this district, if not abso- 
 lutely a necessnry operation in the rectification of the main river channels. This project is 
 ~ed in Part II of my report to the Legislature, and I invite your attention to the views 
 there advanced. 
 
 In my opinion, these creek waters should be turned through a high grade canal over the 
 Montezuma hills, to an independent outfall in the slough north of Suisun Bay. By this means 
 only can the great accumulation of water in the Yolo basin be prevented, the levees of the 
 river be maintained and rendered efficient at reasonable outlay, and the success of the drainage 
 of the valley be rendered complete. 
 
 GENERAL REVIEW OF THE RIVER TREATMENT PROPOSED. 
 
 Glancing over what has been said in this report, and in that made to the Legislature in Jan- 
 uary, it will be found that I have advocated the Conservation treatment in the improvement of 
 the main rivers of this valley; that I propose to bring the channels to a good regimen even 
 capacity to do the duty required by straightening them where necessary and admissible, by 
 scouring out shoals where these exist, particularly in the lower river, by training the current to 
 destroy great eddies, and by preventing the local escape of flood waters" in large volume, and to 
 supplement its present capacity by raising levees which will themselves form a larger channel- 
 way and force the enlargement of that already existing by the scouring action of the confined 
 waters. 
 
 A system of levees necessary. 
 
 And I hold that a levee system is necessary to preserve the existing channels of the Sacra- 
 mento and Feather Rivers and to accomplish their rectification. 
 
 If these channels were more nearly proportioned in size to the. volume of water which comes 
 down the valley, and like many other streams, were deficient in capacity merely because of 
 local obstructions, such as extended bars, their rectification could be accomplished without the 
 levees. But, as has been shown, such is not the case, and we can only accomplish the object 
 through 'the medium of a levee system. 
 
 Could we sweep out of existence all levees now standing along the Sacramento and Feather 
 Rivers, the floods would spread into the back basins at many places, and there, finding shorter 
 lines of escape from point to point on the rivers, would pursue these routes, robbing the channel 
 in some of its divisions of the waters due to it and necessary to preserve its size, and gorging the 
 channel with more than it could carry at other points. 
 
 The result would be the contraction of the existing channels in some of their divisions and 
 the formation of new outlets or the enlargement of those already in existence, until, by the 
 action of some great flood, the channel of the river itself would change materially. This is 
 just what was going on before leveeing commenced here. 
 
 Xow there are levees over four fifths of the route of the river within the district where their 
 waters could naturally escape into the back basins. These levees are of very uneven height, 
 me of them badly located. If they are left in their present condition, and an attempt be 
 made to improve the channels, what will be the result? Manifestly a more unfavorable one 
 than if there were no levees at all. The waters would escape where the levees are weal; 
 where there are none, and in large volume locally, as they do now in reality, and the river 
 could not be brought to a good regimen, for there would be no control of the floods, which 
 would leave the channel or return to it whenever opportunity offered; and without a nearly 
 perfect regimen we can hope for no general improvement in the channel. 
 
 The obj.'ct is to prevent the further deterioration of these rivers and to improve them. 
 
 The detritus lodged in the river beds must be disposed of, and the channels otherwise rectified 
 and enlarged. It is absurd to talk of dredging them all out, as has been publicly suggested. 
 Twenty millions of dollars would not more than free the two rivers by tiiis process. 
 
 A portion of the sediment should be used in levee construction, but the great mass must, be 
 swept out by the river currents. This can only be accomplished by putting the rivers in condi- 
 tion to facilitate this action, and by a control of all ordinary floods; and a system of good 
 strong levees is essential for this treatment. 
 
 .1 system as is n.-c-'s.-ary for this purpose, however, will not effect the complete reclama- 
 tion of all the swamp lands in the great basins of the district, but of course would do much 
 toward that end. There would still be a necessity for organized action in the reclamation dis- 
 tricts which must continue to exist and each labor in its own behalf, while the drainage work 
 
11 
 
 will be for the common good of all. This subject is more fully touched upon in a report sub- 
 mitted by me to the State Board of Drainage Commissioners, under date of the twenty-sixth of 
 May, and to that paper I ask your attention. 
 
 AN ESTIMATE OF COST. 
 
 Concerning the probable cost of the works herein outlined, I can only at this time give a 
 rough idea. To construct levees of proper size entirely anew along the Feather and Sacramento 
 Eivers where necessary within this district, would cost in the neighborhood of three millions of 
 dollars. 
 
 It may be said that one third of this work has been accomplished efficiently thus far, so that 
 it couM be made a part of the work of the future. We have then a balance of two millions of 
 dollars to be expended on this class of work. 
 
 An estimate of what might be expended to advantage within the next ten years may be 
 made, as follows : 
 
 Levee work $2,000,000 
 
 Channel corrections, etc 2;000,000 
 
 Storing sands 1,000,000 
 
 $5,000,000 
 
 Fully one half of this work is such as the general government might possibly undertake for 
 the preservation and improvement of the rivers as navigable streams, but it must be bimight 
 forward in its order with the other works, and cannot be left behind, else the whole will be a 
 failure. 
 
 The work should be so carried on as to diminish the time of execution as much as possible; 
 there would be economy in such a course, for they will undoubtedly cost more unless put in 
 final condition as fast as natural action will permit. 
 
 Supposing the five millions of dollars were expended during the next ten years, I estimate 
 that the cost of maintenance would be about two hundred thousand dollars per annum after 
 that period, half of /which would be for storage of sands and half for river works; and the 
 general government might be expected to bear half of the expense if it pursues its present 
 policy in river works. 
 
 The maintenance of levees, while properly remaining under the direction of the Drainage 
 District Boards, should ultimately be paid for by the lands thus protected from inundation, and 
 thus the State's share of the expense of maintaining her rivers in good condition will, in the 
 future, be reduced to a small amount. 
 
 Very respectfully submitted. WM. H. HALL, 
 
 State Engineer. 
 
 EEPOET ON DAMS FOE THE STOEAGE OF MINING DETEITUS ON THE YUBA 
 
 AND BEAE EIVEES. 
 
 OFFICE OF THE STATE ENGINEER, ) 
 
 SACRAMENTO, July 6, 1880. J 
 
 To the Board of Directors of Drainage District No. 1, Sacramento, Cal. : 
 
 GENTLEMEN: In the matter of constructing dams for storing mining detritus on the Yuba and 
 Bear Eivei-s, I have to report now in general terms, and when further examinations shall have 
 been made of the several sites for dams and storage ground, I will submit another report con- 
 cerning the same, and recommend the adoption of a definite policy on each river. 
 
 Transportation of sediment by moving waters. 
 
 The conditions in a stream most favorable to the transportation of sediments by its waters are : 
 (1), that it be deep in proportion to its width; (2), that it be of uniform width and grade; (3)' 
 that its channel be of good alignment, free from sudden bends; and (4), that the lines of its cur- 
 rents be not broken up by obstructions of any kind. 
 
 With such conditions, a rapid current, uniform in its movement throughout the several suc- 
 ceeding reaches and divisions of the stream, with a sharply inclined vertical velocity curve, 
 would be produced, and the waters would have great power to transport solid matter. 
 
 Eeversing these conditions in any manner, the waters drop their silicious or earthy load in a 
 degree proportional to the extent of the reverse order produced. Thus, sediment carrying cur- 
 rents may be made to deposit their sand and slimes by checking the velocity, and otherwise 
 destroying the conditions essential to their transporting power. 
 
 This may be effected in either one of three ways : (1), increasing the width of the stream, thus 
 reducing its depth as a direct consequence, and indirectly reducing it also by causing the raising 
 of its bed by deposits thereon; (2), reducing the grade" or slope of the stream by changing its 
 alignment, or by raising its bed at some point by a dam ; (3), breaking up the threads of its cur- 
 rent by the introduction of pervious or partial obstructions to its flow. 
 
12 
 
 The Y'.iba and Bear River deposits. 
 
 The Yuba and Bear Rivers have made immense deposits of gravel, sand, and slime above 
 their confluence with the Feather, because their grades greatly diminish as they approach that 
 stream, their waters have overtopped the low banks and spread in wide sheets over the adjacent 
 bottom lands, and the den-v-. gix>wth of small timber and brushwood through which thev were 
 made to run broke up the lines of their currents. 
 
 Bepo-its iii this manner occasioned at lower points, have served to reduce the grade for other 
 points above, and thus, there also, rilling has taken place: and still again, in the canons the 
 natural irregularity of regimen, and the damming up occasioned by the lower mining dumps, 
 have made many extended reaches the storehouses of heavier detritus. 
 
 Proposed artificial deposit of detritus. 
 
 Now it is proposed to cause an increased deposit from the waters of these streams, at such 
 points that it will not damage private property or injure the navigable main drains below. 
 
 So far as the currents of the Yuba and Bear Rivers themselves are concerned, it matters not 
 whether they are either restored or supplemented by other deep ones, so long as the objects just 
 expressed are attained. Indeed, the primary object being to preserve and improve the channels 
 of the main drains or navigable streams the Sacramento and Feather Rivers it would seem 
 to be advisable to avoid any immediate restoration of the channels of the tributaries; for mate- 
 rials washed from them must pass down into these larger rivers, and it is important to withhold 
 all the sand that can possibly be held back, at least until such time as they the rivers below 
 can have been brought to a good regimen and scoured out. 
 
 In view of this condition, I recommend that the treatment for the Yuba and the Bear be such 
 as to retain their channels, for years to come, at least, somewhat as they now are, in wide and 
 shallow beds; and rather encourage further deposits upon the Band wastes already formed 
 (where this can be done without great damage to other yet uninjured property), than to cause 
 the restoration of any deep channels through these deposits. 
 
 This treatment should be pursued until such time as it shall have been shown that the sands 
 are stopped at higher points, and the large rivers below are, in a great measure, relieved from 
 their filling. 
 
 Locations for and character of dams. 
 
 Within the canons of the mountains through which the Bear and Yuba flow, it is not possible 
 by any direct method to.widen the channels. This can only be accomplished by building up 
 their beds through the action of dams, thus effecting the double object of increased width and 
 decreased grade above each dam. 
 
 The subject of retaining the detritus by means of stone dams within the canons of the Yuba 
 River was discussed by me in Part III of the report to the Legislature, submitted in January, 
 and allusion was made to the possibility of effecting the same end by means of dams of brush 
 and gravel at lower points on the same streams. 
 
 Further observation and thought have convinced me that the work should be commenced as 
 low down on the str.-ams as the detritus can be held safely, and that the dams built must at first 
 be of the latter mentioned < 
 
 The sands stored at lower points will themselves serve, to some extent, as dams for storage 
 ve; and furthermore, brushwood is the only material to be had at some of the 
 sites for darns, and these structures must be built of it if at all. 
 
 A brush dam possesses the advantages of greater stability and safety on soft or sandy founda- 
 tions, and great cheapness of construction. 
 
 A rock dam lias in its favor the considerable advantage of the durability of its material and 
 of stability under great floods supposing, of course, its foundation to be secure. 
 
 M the wide sand Hats below the canons proper, undoubtedly brush dams should bo 
 adopted, primarily, at least; while between the high banks of the foothills, rock dams, where 
 material is abundant, can be most conveniently built, and would have the advantage of per- 
 manence to a degree which should render their ultimate adoption advisable. 
 
 Storage below the canons. 
 
 Were the sands stopped at the canon mouths on the Yuba and Bear, it would still be neces- 
 sary in preventing the channeling out at lower points through the sand wastes above the 
 Feather, to lay in some low brush dams or sills, as heretofore alluded to, in order that the^e. 
 might not be swept down before the large rivers could receive them safely. This 
 being the case, it will be wise to make these obstructions do the additional duty of holding more 
 sands if possible, and hence at the lowest point where this can be done with safety, the first 
 dams should be built. 
 
 All of the sands which will come down these streams for several years can be thus .- 
 !-'lo\v the canons proper, on lands already covered; and, by an extension of leveeing work, 
 still greater storage capacity can be obtained over the same superlices. 
 
 Stone dams commenced with brush. 
 
 Th' :.-r of destruction to a stone dam of the character and for the purposes it is 
 
 Ernj-MA-ed to build them on these streams, i> from undercutting at its down stream edge, and in 
 uilding oi stone alone it is difficult and expensive to guard against this action. 
 
33 
 
 With brush, however, this difficulty is much more readily met, and it is proposed to protect 
 the stone dams by submerged brush dams at the down stream edges of their aprons. These 
 brush dams, by raising them higher, can be made to retain a large amount of sand above them 
 before the stone dam is commenced, and hence, again, we have sound arguments not only for 
 the construction of the first dams low down on the streams, of brush, but for the commencement 
 of all dams with that material. 
 
 THE STONE DAMS PROPOSED. 
 
 It may be well to consider here for a moment the principles upon which we are to proceed in 
 the matter of constructing dams, both of brush and of stone. 
 
 Stone dams character of. 
 
 The proposed stone dams would be massive structures of loose rubble, not coursed or hand- 
 laid, but somewhat assorted with respect to size of pieces, as hereinafter explained, with crests 
 ten to twenty-five feet in thickness, and long slopes both up and down stream. 
 
 For a clear idea of the problem of these stone dams, it is essential to remember that they are 
 to be for the purpose of storing sands, and not water, and that it will not be necessary, under a 
 proper system, to have any one of them more than twenty feet say an average of twelve feet 
 in height, at any time, over the bottom immediately up stream from it. Hence the dam be- 
 comes but a facing for an upper plane of sand; it becomes filled and impermeable only by 
 degrees, as the sands rise upon it; and the hydrostatic pressure behind it is always limited to 
 that due to but a few feet in depth of water. Such a dam is intended to be added to each year, 
 using the filling above as a foundation for a portion of each addition, until the structure is 
 brought to the desired height for its site and becomes solidified with the filling against it. 
 
 Stone dams their weak points. 
 
 If rocks of sufficient size are used, its destruction could only be accomplished: (1), by the 
 water finding a low place in the crest, and there concentrating its force; (2), by undermining; 
 or (3), by flanking its ends. 
 
 The mere pressure of water or shock of a flood could not overthrow a dam of this kind; so 
 that its destruction, if ever accomplished, could only be gradual, and not a sudden catastrophe. 
 
 Ordinary care in construction and maintenance, and the use of very large stone on the crests 
 and down-stream faces, would prevent damage from channeling down and concentration of 
 waters at any point. 
 
 Ordinary good construction, too, will insure against the ends being flanked by the floods, for 
 the water may be kept away from the extreme ends of the crest, and a good junction may be 
 made with the bedrock in the faces of the hills. 
 
 On the foundation, we have the weakest line to guard. 
 
 If large rocks say twenty tons apiece be laid in a row on the sands across the bed of a river, 
 such as the Yuba or the Bear, they will quickly disappear the sands from between them will 
 scour out, the rocks will gradually drop into the cavities produced, and will soon have dis- 
 appeared almost entirely, if not quite. 
 
 If the same quantity of stone, broken to the size of ordinary river gravel, be placed in a ridge 
 across the channel in a similar locality, it will not be undermined; the top stones will be swept 
 off, probably, one by one, by the force of the current, and the whole ridge flattened down, in 
 time possibly destroyed by this means, but it will not be dropped out of sight, in the sands, by 
 the action of the current passing under it from above. If there should be considerable fall over 
 it, and no apron or flat surface of stones below, the sands would probably be swept away from 
 it's down-stream edge, and the stones or gravel would be washed into the cavity thus formed. 
 
 Here we have a picture of the manner in which a rubble-stone dam may be undermined, 
 either by the water running along upon the sands, by way of the spaces, between the stones 
 that compose the structure, from above, or by the cutting under the lower edge of the structure 
 after having passed over its crest. 
 
 Stone dams for storing detritus principles to be observed. 
 
 Should we imagine a dam built up in thin layers, the material in each succeeding one graded 
 in size somewhat larger than in the layer below from the dimension of the particles of sand 
 up to those of- the great mass of rock capable of withstanding any force of water that can 
 possibly be brought to bear upon it we would have before us a dam totally incapable of 
 destruction by undermining from above, because the interstices between the particles of no one 
 layer would be sufficiently great to admit the passage of a stream of water strong enough to 
 wash out its particles or those in the layer next below. 
 
 In tbe construction of stone dams to'store the detritus on the Yuba and Bear Rivers we must 
 approach this condition in their parts; the sands under the foundation must be covered so that 
 the waters of percolation will not wash them ; the rocks upon the crests must be of such great 
 dimensions that the force pf the water cannot move them, and the pieces of the intervening 
 material must be intermediate in size. 
 
14 
 
 t 
 
 Practical construction of stone dams. 
 
 The foundation may be secured, by first depositing layers of very fine stone upon which to 
 build: or the same object may be attained by building the stone dam upon a foundation 
 mattress or matting of small brush, with fine stone or gravel intermixed. 
 
 Having secured the foundation from washing above, the undei'cutting at the toe must be 
 guarded against. 
 
 First of all, for a considerable width below any overfall, there must be an apron to receive 
 the shock of the waters and permit of their taking a horizontal direction in the onward flow, 
 before reaching the movable bottom. 
 
 This apron, of course, would be most durable if constructed of stone, provided its under- 
 mining were guarded against, and to a stone dam there should be a stone apron, though 'one of 
 logs or of brush and gravel might be used safely for years. 
 
 The lower edge of such an apron, of whatever material composed, unless it were of very great 
 width and the water spread over it in a very thin sheet, would be liable to suffer from this 
 undercutting influence, unless the transporting power of the water were broken up at that 
 point. 
 
 Flowing over or past a hard and fast line, such as the edges of a stone or log apron would be, 
 water almost always attacks the soft material adjacent to it, and cuts a hole or pit. On the 
 contrary, a windrow or driftrow of brush, lodged in a current so that the waters partially pass 
 between the branches, causes a deposit of sediment and the formation of a bar below, which 
 works up to and finally covers in the brush itself. 
 
 By a proper construction and the use of brush on this principle, with which to finish the 
 lower edge of the stone aprons, not only may their undercutting be prevented, but the sands 
 may be caused to pile up where it might be supposed they would cut out. 
 
 I do not propose to consume time and space in citing instances where like effects have 
 been artificially produced in engineering work. Suffice it to say, that the annals of modern 
 river engineering afford analagous examples, and the working of the law upon which the result 
 rests may be observed in nature every day, and in many places upon our own streams. 
 
 I am of the opinion, therefore, that stone dams of this character can be put upon the saud 
 foundations in the lower portions of and at the mouths of the canons of the Yuba and Bear 
 Eivers with perfect safety. 
 
 Dams for storing detritus, and other stone dams. 
 
 I remark the difference in principle upon which we should proceed in laying the stone dams 
 here contemplated, from that followed in placing stone foundations for other purposes. 
 
 In the case of the proposed rubble dams, we expect percolation through them, and only guard 
 against the washing out of the material below by covering it in with other material, the" nature 
 or arrangement of which will not admit of the washing. 
 
 We have water highly charged with silt, which it is expected will deposit its load in the dam 
 as the sands are rolled against it. We are not constructing to hold clear water, or to bear a 
 heavy load. 
 
 In stone foundations for a bridge or a masonry dam, the work itself is intended to be imper- 
 meable and immovable from the commencement; the largest stones may be placed at the bot- 
 tom, and it is not intended that they should move. 
 
 In the case of the proposed rubble dams, although they must be placed on good sand and 
 gravel foundations, and not on quicksand or "slickens," settlements which will be utterly 
 destructive to works of the other class, would not be a serious circumstance ; indeed they are to 
 be expected, and the dam's crest must be brought up to grade as well as raised, perhaps, to 
 accomplish more storage each year. 
 
 Stone, the proper material for the future; brush, for the present. 
 
 And, in view of the fact that all dams to be used in storing this material should be as perma- 
 nent as possible, I think the great mass of it in the future should be stored above stone works. 
 
 But, considering what has preceded in this paper, I am clearly of the opinion that the work 
 should be commenced with brush structures, and possibly this brush work can be used in other 
 ways so as greatly to cheapen the stone structures, as hereafter suggested. 
 
 THE BRUSH DAMS PROPOSED. 
 
 Concerning brush dams there is not so much to say. The illustration heretofore cited of a 
 driftrow of brush lodged in a current, affords the idea of the simplest form of such a work, and the 
 natural growth of brushwood and small timber over the sand flats in Yuba Eiverand Bearlliver 
 presents another excellent example of a pervious brush dam, which causes a deposit commenc- 
 ing below it, by breaking up the lines of the current, and thus destroying its capacity to transport 
 its load of solid matter. 
 
 Natural brush dams. 
 
 One cannot long study the action of this growth in the localities mentioned, without being 
 thoroughly convinced of the efficiency of the brush dams which nature thus rears in the way of 
 the floods'with their charges of sand. 
 
15 
 
 It has only to be seen for the fact to be appreciated, that but a small proportion of the solid 
 matter is carried through such an obstruction, and that it would only be necessary to close the 
 channels intervening between the great growths of young trees, by similar obstructions, to 
 cause an almost complete intercepting of the detritus. 
 
 Thus, were the sand-covered fiats of the Yuba and Bear Rivers flanked by high plains or 
 levees, they might be made to retain the sediment to be brought down for a number of years 
 to come, by simply causing the- sands to rest upon them on greater grades, by placing low per- 
 meable brush dams at short intervals of space in the way of the currents, and adding to them 
 from year to year. 
 
 As it is, however, no such banks exist very far down into the plain; the time has passed 
 when this action could have been availed of to any great extent without artificially confining 
 the waters on the sides, and for this purpose very large levees must be now constructed, although 
 by such means the storage room below the foothills will be increased, yet it is limited, and we 
 must look forward to the time when it will be exhausted. When we can no longer raise the 
 lower portion of the storage ground there will be an overfall necessary at some point the 
 lowest limit of the deep storage and for that a pervious brush dam will not suffice. 
 
 There must be a firm structure down whose face water may fall, as over a stone dam, without 
 washing out any of the material in or under it. 
 
 Impervious brush dams. 
 
 Of gravel and brush or small trees, such a dam can be readily built to a moderate height. 
 
 The main structure, in order that it may be firmly held to the sand and gravel, must be built 
 with the tops of the trees up stream with their branches covered in and incorporated with 
 gravel or coarse sand, by which arrangement also the butt ends are placed down stream and 
 form the overfall face and crest of the dam . 
 
 A heavy apron, immediately below the overfall, should be constructed in similar manner; 
 while to prevent the undercutting action from below, a lower apron must be provided with the 
 brushy ends of the trees down stream. 
 
 We would thus have a dam as immovable as a drift tree which lodges upon a sand bank and 
 forever forms a snag, unless removed-by human agency. 
 
 Stability of brush dams. 
 
 If we consider the width to which the waters of the streams now under discussion are spread 
 at the points where it is proposed to construct brush dams, we will realize how they will be 
 robbed of their destructive force by being led to encounter an obstacle such as a dam in the face 
 of the entire front of their flow. 
 
 For instance, the extreme flood discharge of the Yuba River is about fifty thousand cubic 
 feet per second, and its ordinary flood discharge does not exceed half that amount, while its 
 usual discharge through the Winter and Spring is about five thousand cubic feet per second. 
 
 I take the larger figure to illustrate the case : At the De Guerre dam site, the shortest pro- 
 posed line of construction for a brush dam, the overfall will be about five thousand feet in 
 length. Fifty thousand cubic feet of water per second, running at a speed of ten feet per sec- 
 ond, will pass over a crest five thousand feet long in a sheet one foot deep, or running at the 
 rate of five feet per second, it would pass over the five thousand foot crest two feet in depth. 
 
 In actual practice it would run at a rate according to its velocity of approach to the dam, 
 which would make it from 1.3 to 1.7 feet deep over it. 
 
 With a stick to brace himself, a man could almost wade across the Yuba River, on the crest 
 of such a dam at the time of its greatest discharge, and could certainly do so at time of ordinary 
 flood, provided the dam was so placed and constructed that the water approached it with nearly 
 equal velocity at all points. 
 
 Now, a sheet of water a foot and a half deep, moving at the rate of seven feet per second, 
 represents about the maximum moving force we have to contend against, and under such cir- 
 cumstances it will not be a difficult task to construct brush aprons below the dam, and so guard 
 them as to insure against undermining. 
 
 We have examples of brush dams of comparatively slight construction in California which 
 have long withstood the action of water running over them to an equal, if not a greater depth. 
 
 Governing the deposit of detritus. 
 
 There can be no doubt but that the gravel, sand, and much of the finer sediment brought 
 down by these rivers can be deposited almost wherever it is desired to place them within the 
 territory now covered by the sediments, and held there permanently by brush work only, to a 
 height varying from one to twenty feet, in addition to the depth of detritus already in place. 
 
 The practical limit to thus disposing of this sand will be found in the leveeing to prevent the 
 overflow of adjacent lands. 
 
 Recent river works have shown in a wonderful degree what complete control the engineer 
 may have over the currents and their sediments, if he only study his subjects closely and seize 
 upon local advantages. 
 
 We all know that a lattice fence, forms a complete wind-break. Sands blown up from the 
 beach are arrested and made to pile up in great dunes or ridges parallel to the water front by 
 the construction of light wicker work or brush fences. 
 
16 
 
 of this kind are numerous in older countries, and the experiment was successfully 
 carried on f<>r several seasons under my direction at the seaward end of Golden Gate Park in 
 San Franei 
 
 Similar constructions which do not present enough resistance to the currents of water to be 
 swept away or undermined by them are now used to gradually check their velocity and to force 
 them to drop their sands like those blown by the winds from the beach where the engineer 
 desire- to have them rest. 
 
 Within the last two years, upon the Missouri River, near Omaha, a greater advance has been 
 made in this class of work than was previously chronicled to my knowledge. 
 
 I here quote from a popular account of these operations, recently published in the Scientific 
 ferring 711 ore extended notice of the official report spoken of, and the detail's" of 
 works, until I submit to you a special report on the improvement of the larger streams in your 
 district. 
 
 Experience on the Missouri River. 
 
 Speaking of the Missouri River, the journal, after describing the action of the stream at cer- 
 tain points, says : 
 
 To keep the river within regular bounds the yielding banks have to be protected, the 
 velocity of the current diminished in certain places/and the channel held in place by building 
 up or solidifying its sides. The different means employed in this sort of work are described by 
 Captain llanbury of the Engineer Corps, in a recent report upon the condition of the Missouri 
 Kiv.-r, near Omaha. For causing deposits to take place, and for deflecting the currents in 
 localities that are to be built out, floating brush obstructions have been applied with marked 
 success. The most successful of these is the floating brush dike, 7iiade by taking saplings from 
 twenty to thirty feet long, and from four to six or eight inches in diameter, and nailing or 
 na to them with wire, scraggy brush of any kind obtainable in the locality. This forms 
 what is known as the 'weed.' Instead of the saplings rope may be used to hold the brush. To 
 one end of this 'weed' is attached an anchor of sufficient weight to hold it in position against 
 the current j to the other a buoy to hold up the down stream end and prevent it from going to 
 the bottom under the pressure of the current against it. These 'weeds' are placed from ten to 
 twenty feet apart, thus forming the floating dike. Their action is to check the current 
 gradually, without producing that scouring effect to which the solid dike gives rise. This done, 
 a portion of the material which is rolling along the bottom or being carried down in suspension 
 is deposited, and causes a rise in the bed of the river, which changes its channel to the direction 
 desired. The rapidity with which these deposits take place is truly wonderful. One season is 
 often sufficient to raise the river bed up to the limits of ordinary high water. 
 
 "Another form of obstruction that has been tried with success is the willow curtain. This, 
 os iis name indicates, is 7nade of willows about an inch in diameter or larger, fastened parallel 
 with each other, and from six to eight inches apart, by means of wire. The curtains can be 
 made of any desired width and length. They are anchored in position by weights attached at 
 intervals along the lower edge, aiid held in an upright or inclined position in the water by 
 floats made, fast to the upper edge. Their action is similar to that of the ' weeds.' 
 
 "Another form that has been experimented with, and which bids fair to give good results, is a 
 screen made totally of wire, something after the fashion of a seine. It is anchored and buoyed 
 like the willow curtain. The rootlets and small vegetable fibers that float in large quantities in 
 the water accumulate upon the wires, and form obstructions sufficient to check the velocity of 
 the current." 
 
 Application of the above experience. 
 
 Here we find remarkably favorable results produced in a deep and rapid river, by methods 
 the most economical and safe in their application. It only requires an intelligent study of our 
 circumstances here to apply S07iie one of these contrivances successfully in each case. 
 
 For instance. I do not doubt that the Yuba River, now coursing down the line of the north 
 levee, for about three miles of its length, transporting a great volume of sediment past it daily, 
 can be made to deposit this load where it now threatens erosion, by the use of some such means as 
 the brush curtain applied on the Missouri River. Thus, by checking the current at short inter- 
 vals by these screens, we would build up a levee strong enough to resist all attacks of the 
 floods for there is no reason why it should not be a thousand feet through on the base, all 
 deposited by the water itself up to the height of the flood line. 
 
 These screens are really open work brush dams, and act as has been described before of such 
 works. 
 
 There are circumstances, then, under which pervious brush dams may be used to advantage 
 on the Yuba and Bear Rivers, but to store the great mass of sands that are to come down these 
 rivers, eve during the first few years of this work, more substantial structures will be required 
 of brush and grave), and in the future the great mass of detritus must be held by rock dams 
 between the foothills as before described ; unless, indeed, it is proposed to let these sands spr.-ad 
 over large areas of land as yet uninjured. 
 
 And bore I remark that the application of this idea of causing the waters to deposit their 
 burden of detritus by opposing at short intervals permeable obstructions to their flow, is almost 
 illimitable. 
 
 By the use of heavy brush curtains trailing in the waters, a7id swung from shore to shore in 
 
17 
 
 the wider parts of the river canons by means of cables, it would be possible to arrest the great 
 mass of sands between a series of low rock brush rapids, and thus fill up the whole canon for 
 a number of miles in length at once, without the use of any heavy dams at all. 
 
 The cost of the work would probably be excessive, however, and the plan is only mentioned 
 to show to what extent the possibilities in this matter reach. It is evident that sediment-bear- 
 ing waters may be made to deposit their load under any ordinary circumstances; but it is also 
 clear that if the waters are to continue to run over the deposit, some more stable obstructions 
 must be introduced to prevent subsequent erosion. Hence the introduction of the rock and 
 brush riffles spoken of above. 
 
 Our work not an experiment in the popular sense. 
 
 It is well in this connection, also, to allude to one more point. It has been said that this work 
 is altogether experimental. This assertion is not correct. 
 
 Nothing is more certain than that the flow of these sands can be arrested before they reach 
 the main ri.vers; the engineering principles upon which we are to work are well understood, 
 and their operation proven. 
 
 But, under the particular circumstances which we have, there is a question as to how the 
 object can be most cheaply accomplished. 
 
 To this extent the work is experimental, and if carried forward intelligently it cannot but 
 result in showing, after the first year or two of trial, wherein economies may be practiced and 
 the object attained at less cost, as all river works have before it. 
 
 SPECIFICATIONS FOR BRUSH WORKS. 
 
 On this day I hand you specifications for brush dams on the Yuba and Bear Rivers. 
 
 They are drawn for heavy dams, intended to become rapidly impermeable as the muddy 
 water flows over them, and upon the principle heretofore laid down. In my opinion, it will be 
 necessary to put such structures, at least, across all open channels where the force of the current 
 at flood time is to be resisted, and it is intended to cause a deposit for the full width of the 
 stream ; in other words to store the detritus above the dam. 
 
 Where the line of a dam is located through a heavy growth of brushwood, or young timber, 
 the character of the structure may be changed so as to effect a material saving in construction. 
 
 A belt of such timber left standing forms a dam for our purposes itself, and taken as the 
 framework of a permeable dam, this kind of a structure might be put up through such a belt 
 at a very moderate cost, in line with the heavier dams across the open channels. 
 
 I do not attempt to draw specifications for this class of work at this time. Indeed, so much 
 will depend upon the exact character of the growth itself, that it will be necessary to examine 
 each line in detail before any such attempt can be made to advantage. 
 
 When the lines of the proposed dams can be gone over after the water has fallen somewhat 
 more, I will, if desired, make specifications as are required. 
 
 Difficulty of describing river works in detail before construction. 
 
 Here let me call attention to the difficulty of drawing a description of such works sufficiently 
 in detail upon which to contract. 
 
 The best laid plans for this class of river works have almost always to be changed to suit the 
 peculiar circumstances and conditions found or developed during the course of operations. 
 
 Frequently it may cost near as much to make the examinations necessary upon which to base 
 specifications for such works as it would cost to do the work itself under management, where 
 there was latitude for the exercise of discretion on the part of the engineer in charge. 
 
 And I desire to be understood now as saying that much must be left to the judgment of the 
 engineer in charge, who, as the work progresses, should fit its details to the conditions pre- 
 sented. 
 
 For this reason it would be much better if this work could be done by day labor, and not 
 under contract; though it is possible that the objections to this arrangement from other causes 
 would more than counterbalance the advantages presented upon the score just spoken of. And 
 yet I cannot see how the thousand and one little jobs of work, which I may with truth call 
 stitches in time, that will have to be carried forward by your Engineer, can be done by contract. 
 It will cost as much to advertise some of them as it will to do them. 
 
 Very respectfully, your obedient servant 
 
 WM. HAM. HALL, 
 
 State Engineer. 
 
 From the foregoing reports it will be observed that in consonance 
 with the law ^ under which we are acting, the sole object of our 
 endeavors is directed to promoting drainage, and while some of the 
 operations may, to a secondary extent, produce results apparently at 
 variance with this theory, yet, in every instance, the primary object 
 3" 
 
18 
 
 has been, and is, to expend the funds intrusted to our management, 
 in such manner only as will further the end in view, viz.: to so 
 improve the regimen of the main artery, the Sacramento River, that 
 it may safely, and with certainty, conduct the waters o its tributa- 
 ries to the great outlet which nature has provided. As a sequence 
 of this result, the navigation of the Sacramento will doubtless be 
 improved, the lands adjacent to the stream will gain protection, the 
 debris from the mines will be arrested, and many minor advantages 
 gained, but they are all secondary, and dependent upon the one pri- 
 mary object. 
 
 It will also be observed that two general classes of works are rec- 
 ommended, the first being preventive, and having for its object the 
 restraining and impounding the sands of the tributaries, and thus 
 preventing their entrance into the navigable waters of the main 
 streams ; the second, remedial, and intended to improve the channels 
 of the streams as flood-carrying and navigable channels. In pur- 
 suance of the first of these objects, and for the purpose of arresting 
 the flow of detritus from the mines, we have caused to be constructed 
 permeable brush dams across the Yuba and Bear Rivers. 
 
 That upon the Yuba is located, approximately, seven and one-half 
 miles above Marysville, is nine thousand six hundred feet in length, 
 and has an average height of seven feet. 
 
 That upon Bear River is located at Johnson's Old Crossing, about 
 three miles above Wheatland, is six thousand feet in length, and has 
 an average height of six (6) feet. 
 
 The following specifications will serve to illustrate the mode of 
 construction of those dams, it being premised that the one on the 
 Yuba is located at what is designated as Site Number Two (2), and 
 not at the point first proposed, and that the specifications were some- 
 what modified, both before the work began and during its progress. 
 For an account of these modifications, and the reason therefor, we 
 refer to the report of the State Engineer, which will be submitted to 
 you. 
 
19 
 
 SPECIFICATIONS 
 
 FOR A BRUSH DAM ON THE YUBA RIVER, DRAWN FOR PROPOSED LINES FOR 
 DAM NUMBER ONE. 
 
 DAM EIGHT FEET HIGH. 
 
 Cross section of dam, exclusive ) , nn f _ 
 
 of backing . } 400 square feet. 
 
 EXCAVATION 
 
 Pit at heel of dam 64 
 
 Pit at toe of dam 130 
 
 194 
 
 Solid contents of the ) 
 
 timberand brushin [ 10. 37 cu. yds. (2. 19 cords) per 1 footofdam. 
 the dam, 70 per cent. J 
 
 Ballast in dam, 30 per cent. 4.44 cu. yds. per 1 ft. of dam. 
 
 Gravel backing 2.00 cu. yds. per 1 ft. of dam. 
 
 Excavation 7.19 cu. yds. per 1 ft. of dam. 
 
 TREES REQUIRED PER ONE FOOT OF DAM. 
 
 1.35 trees, 8 inches in diameter, 33 feet long. 
 1.35 trees, 8 inches in diameter, 34 feet long. 
 1.35 trees, 8 inches in diameter, 35 feet long. 
 1.35 trees, 8 inches in diameter, 36 feet long. 
 3.60 trees, 6 inches in diameter, 17 feet long. 
 3.60 trees, 6 inches in diameter, 16 feet long. 
 3.60 trees, 6 inches in diameter, 15 feet long. ' 
 3.60 trees, 6 inches in diameter, 14 feet long. 
 4.32 trees, 7 inches in diameter, 17 feet long. 
 1.44 trees, 7 inches in diameter, 20 feet long. 
 1.44 trees, 7 inches in diameter, 23 feet long. 
 1.54 trees, 7 inches in diameter, 33 feet long. 
 1.54 trees, 7 inches in diameter, 30 feet long. 
 1.54 trees, 7 inches in diameter, 28 feet long. 
 1.54 trees, 7 inches in diameter, 26 feet long. 
 1.54 trees, 7 inches in diameter, 24 feet long. 
 34.70 
 
20 
 
 SITE AND CHARACTER OF THE DAM. 
 
 1. The site of the proposed dam is on the Yuba River, 9.28 miles in a direct course above the 
 county bridge, across that stream at Marysville, and in a line immediately across the general 
 direction of the river from the long rocky point which puts out from the north highland shore 
 into the sand and gravel covered bottoms, now occupied by the waters as a flood channel. 
 
 2. The alignment of the work --designated "site of the proposed dam No. 1," as determined 
 upon preliminarily, is shown on the detail map of Yuba River, to be seen in the office of the 
 State Engineer, or the office of the Board of Directors of the Drainage District in the State Cap- 
 itol building, and the position of this line is marked at each end on the ground by a redwood 
 stake, 6x6 inches square, to which is attached a small pole and flag; the post being marked 
 with the brand of the -State Engineer Department (S. E. D., !.) 
 
 3. In the direct course the distance across the high-water river bed between these posts is 
 about 4,800 feet. The sands of the high-water channel occupy about 4,600 feet of this distance, 
 and vary but little from a level plane in their profile along this line, except at several points 
 where channels three to five feet in depth are cut down. At their low stage the waters run in 
 these channels, or one of them, to a depth of one to two feet. The bottom of these channels are 
 of gravel, and the intervening plane, composed of sand and gravel, is at points covered by a 
 slight growth of timber and brushwood. The northern end of the line is on a bold rocky point; 
 the southern end on a sloping earth bank. 
 
 4. It is proposed to construct on the site thus described a dam of brushwood and gravel, to a 
 height of eight feet above the average elevation of the ground's surface, and it is presumed 
 that this dam will range in height from four to twelve above the foundation. 
 
 5. Accompanying these specifications will be found a tracing sheet marked, " Plans for the 
 proposed brush dams," exhibiting cross-sectional drawings, with dimensions and quantities of 
 materials (as estimated) in the .proposed dam for elevations ranging from six to ten feet, 
 inclusive. 
 
 6. From these drawings it will be seen that the structure will consist, in general terms, of 
 close crib-work, composed of small trees with the branches and bushy tops for the most part 
 left on, the spaces between the trees and branches being closely packed with gravel and small 
 brushwood. And further, that the upper toe of the structure is heeled in below the surface of 
 the ground with its top on 1 a level therewith, while the main part, which forms the dam proper, 
 rests upon the natural surface adjusted to a level plane. 
 
 LONGITUDINAL DISPOSITION OF THE DAM. 
 
 7. This dam is to be constructed so that its crest, as represented by the upper edges or corners 
 of all the three butts which end at the top surface throughout the width thereof (up and down 
 stream) and for at least 4,000 feet uninterruptedly of its length, on completion and final accept- 
 ance of the work, shall be within four tenths of a foot of one level plane. So that allowances 
 made for settlement must be agreed to by the contractor before and during construction, as the 
 exact circumstances of foundation and character of material are ascertained : and the work 
 must be so done, at the contractor's risk, that the condition, as to elevation of crest, will be 
 present on final completion as aforesaid. 
 
 8. On completion and acceptance, also, the down-stream edge of the dam's crest must be in 
 such alignment that it will nowhere depart more than one foot from the straight line forming 
 its ends, and the over-fall face must be on a uniform slope of about forty-five degrees, as shown 
 in the drawings. 
 
 9. Each way from the level portion (the position of which will be designated by the resi- 
 dent engineer on commencement of the work) the darn's crest must rise towards the ends thereof 
 on slopes of from two in one hundred to six in one hundred, as may be determined upon by 
 the resident engineer, preserving a level-topped cross section, and ending at an elevation of 
 six (6) feet above the plane of the level portion. 
 
 10. According to the shape of the ground surface and character of the material found along 
 the line, the foundation of this structure is to be laid in level benches in depths below the 
 general surface of the adjacent portions of the stream-bed, approximating closely to those 
 shown on the diagram of cross-sections. The exact grade of each bench or division will be 
 determined by the resident engineer before or during the work of construction, when the 
 character of the material and shape of the surface becomes known. Each two adjacent benches 
 in the foundation are to be connected by a slope not in excess of one on ten in degree of incli- 
 nation, and no bench shall be less than one hundred feet in length, exclusive of any such 
 slope. 
 
 CROSS-SECTIONAL DISPOSITION OF THE DAM. 
 
 11. When finally completed and accepted as a whole, the crest (as before defined) of this dam 
 shall nowhere vary more than four tenths of a foot from a level plane in any line across it. 
 The trees on the up-stream face of the dam must lie in a plane sloping within five degrees of 
 the inclination which corresponds with a slope of one on two (1 on 2), and its down-stream face (as 
 made up by the butts of the trees in the body of the dam) must lie in a plane sloping within 
 five degrees of that corresponding to a slope of one on one (45). 
 
 12. The plane of the lower apron (as shown by the red line in the cross-sectional drawings) 
 in each longitudinal bench-division of the work must be within two tenths of a foot of the 
 
21 
 
 grade set for it, which will be even with the average elevation, as at first found, of the ground's 
 surface adjacent to its lower edge. 
 
 FOUNDATION OF THE DAM. 
 
 13. Upon making a profile su/vey and drawing of the site of the dam, the resident engineer 
 will lay out the work in divisions, each of which shall be at least one hundred feet in length, 
 and subsequently the foundation is to be laid down in each of 'such divisions as a whole, or in 
 subdivisions not less than one hundred nor more than two hundred feet in length, as may be 
 deemed best by the engineer. 
 
 EXCAVATION. 
 
 14. For at least half of such division or subdivision, as the case may be, the excavation is to 
 be made complete to the determined sub-grade before the laying of the brush is commenced 
 within the same. 
 
 15. The work of excavation may be carried on by any method 'to suit the contractor's con- 
 venience. Spare material must not be left in a continuous ridge below the apron, but such 
 ridge, if made in the process of excavation, must be broken through at one hundred feet inter- 
 vals, and free escape ways must be provided for the water on a level with the top of the adja- 
 cent portion of the apron for at least half of every subdivision of the work. 
 
 16. The depth and width of the excavations for a dam of each sized section probable are 
 shown on the diagrams heretofore referred to, and these dimensions are to be closely adhered to 
 in each instance, on the average throughout each division of the work, except as" provided in 
 next paragraph. 
 
 17. In cases where the material found in excavation is not such as, in the opinion of the 
 engineer in charge, it is desirable to build on, the contractor will be required to continue exca- 
 vation, if necessary so to do, to as much as twice the depth originally designated on the profile 
 and diagrams of cross-sections, and build the structure thereon at the contract rates for the 
 work ; provided, that no excavation shall ever exceed six feet in depth on the average for any 
 one hundred feet of foundation. 
 
 18. It being understood that only in case of such material as soft slime or "slickens," and 
 
 Silicic-sand being encountered or other substances which would render the foundation unsafe in 
 le opinion of the engineer in charge, are the excavations to be. made deeper than those origi- 
 nally set out on the profile when the grades are first established. 
 
 19. In case materials of such consistency that the foundation pits cannot be maintained 
 after excavation are encountered, then, in the discretion of the engineer in charge, the excava- 
 tions may proceed in smaller subdivisions at a time than those heretofore designated, which 
 shall be immediately filled with brush and gravel to such an extent and in such manner as the 
 engineer in charge may direct. 
 
 20. In general, the sub-grade of the structure, being the ground surface upon which the 
 structure is to rest, is to be disposed as shown in the cross sectional drawings, and the longitu- 
 dinal profile hereafter to be made as aforesaid. 
 
 THE STRUCTURE. 
 
 21. Upon the ground surface thus shaped and prepared, the structure is to be built in the 
 following manner : 
 
 22. The lower apron laid entirely beneath the average plane of the ground's surface, is to be 
 first built in each division or subdivision of the work. 
 
 23. It is to be composed of small trees, varying from twenty-five to thirty feet in length in 
 the averaged sized structure (and of greater or less length, as shown in the drawings for the 
 larger and smaller cross sections), and four to eight inches in thickness of butt, laid close 
 together lengthways up and down stream, in horizontal layers, separated by smaller poles placed 
 at right angles to the direction of the trees in the layers, the whole to be consolidated and filled 
 in with small brush loaded and incorporated with gravel to the extent of thirty per cent, in 
 bulk of the structure. 
 
 24. The poles of each set are to be spiked solidly down upon the tree trunks below, and the 
 trees of each layer are to be solidly spiked down to the poles upon which they rest. Tree nails 
 of hard wood may be used in this fastening, or iron spikes of sufficient length to take at least 
 two and a half inch hold may be used. 
 
 25. The upper apron, laid partially below and partially above the natural surface of the 
 ground, is to be next built/ in each division or subdivision of the work. As shown in the sec- 
 tional drawings, this apron rests partly on the lower apron and partly on the ground, up stream 
 from it. 
 
 26. It is to be composed of the same class of materials as the lower apron, and laid in the 
 following manner: Small trees or trunks of trees, varying from fifteen to twenty-five feet in 
 length in the average sized structure (and of greater or less length, as shown in the drawings 
 for larger and smaller sections), and six to nine inches thickness of butt are to be laid close 
 together lengthways up and down stream, in layers sloping dowi.iw,ards and retreating up 
 stream, the butts exposed on the down stream edge of each layer, covered or buried at the up 
 stream edge, and for the greater portion of their length. Alternating with these layers of trees, 
 poles of smaller diameter are to be laid, crossing the trees at right angles. The spaces are to be 
 
22 
 
 filled in with small brush loaded and incorporated with gravel to the extent of thirty per cent. 
 of the bulk of the structure. 
 
 27. The poles of each set are to be solidly spiked clown upon the tree trunks below, and the 
 trees of each layer are to be solidly spiked down to the poles upon which they rest. Tree nails 
 of hard wood may be. used in this fastening, or iron spikes of sufficient length to take at least 
 a four inch hold may be used. 
 
 THE DAM PROPER. 
 
 28. The dam, resting partially upon the up stream edge of the upper apron, partially upon 
 the ground's surface next above, and partially in a pit at the upper edge, is to be next built in 
 each division or subdivision of the work. 
 
 29. Its composition and the arrangement of its parts is similar to that of the upper apron. 
 Small trees or trunks of trees fourteen to eighteen feet in length and six to nine inches in 
 diameter of butt, are to be laid close together lengthways up and down stream, in layers 
 sloping downwards, in an up-stream direction, the butts exposed on the down-stream edge of 
 each layer. Alternating with these layers of trees, poles of smaller diameter are to be laid 
 crossing the trees at right angles. The spaces in the layers and between the layers are to be 
 filled in with small brush, loaded and incorporated 1 , with gravel to the extent of thirty per cent, 
 of the bulk of the structure. In this manner the dam is to be built up to the intended 
 elevation of its crest; and then trees of larger diameter and thirty to forty feet in length are to 
 be used, as shown in the sectional drawings, with their butts in rows forming the top surface of 
 the dam, their trunks sloping downwards up-stream, on an angle of about one below two, and 
 their tops buried in a pit and incorporated with gravel and brush as in other cases provided. 
 
 30. The dimensions of materials in the darn are given for the average sized structures (that 
 eight feet high) : larger trees are to be used where the dam is higher, and smaller may be used 
 where it is lower. 
 
 GRAVEL BACKING. 
 
 31. On the up-stream face of the dam, and on the toe thereof, a bank of gravel is to be 
 placed, as shown in the drawings, in amounts in the different divisions of the work varying 
 with the height of the structure, as follows : 
 
 On a 4 foot dam, 1.00 cubic yards of gravel per linear foot. 
 On a 6 foot dam, 1.50 cubic yards of gravel per linear foot. 
 On a 8 foot dam, 2.00 cubic yards of gravel per linear foot. 
 On a 10 foot dam, 2.50 cubic yards of gravel per linear foot. 
 On a 12 foot dam, 3.00 cubic yards of gravel per linear foot. 
 
 STONE BACKING. 
 
 32. In the discretion of the Board of Directors a rough stone backing may be substituted for 
 the gravel backing; this point to be determined after opening the bids for the work. 
 
 33. In case such stone backing is adopted, then it shall be placed as is the gravel backing, 
 or as directed by the engineer in charge, and the amount of stone used will be about two thirds 
 of those designated for the different heights of dam for a backing of gravel. Special figures in 
 the bids for gravel and for stone will be required, as hereafter provided. 
 
 THE ENDS_OF THE DAM. 
 
 34. At the northern end this dam is to be set in a bench cut in the rock point from which it 
 there springs, in such manner as may be designated by the engineer in charge; provided, that 
 the excavation necessary shall not exceed 600 cubic yards in amount. 
 
 35. The end of the dam itself is to be thoroughly covered and protected with rough stone, as 
 may be directed by the engineer in charge; provided, that the amount of stone necessary shall 
 not exceed 1,200 cubic yards. The character and size of stone shall be same as that for backing, 
 as before specified. 
 
 36. The southern end of the dam is to be similarly covered in and protected, and connected 
 with the face of the hill or slope against which it will rest, and the same provisions are to 
 
 appJy- 
 
 37. And all concerning this end finish and protection of the dam is to be considered with 
 the proviso that the Board of Directors may adopt whatever method or plans of work they may 
 consider best under the circumstances, and may, for as much as 1,000 feet in length, at the 
 southern end of the work, substitute or append an earthen embankment or levee, protected on 
 the upper face by a rip-rap covering of rough stone, in pieces not less than one cubic foot in 
 length. 
 
 END TRAINING WALL. 
 
 38. At the southern end of the overfall of the dam, a training wall, built as a groyne to the 
 dam and in a similar manner to the dam itself, is to be carried out from the lower face of the 
 dam to a distance of one hundred feet and returned, parallel to the dam, to the hard bank 
 land, to a distance not exceeding four hundred feet, and this shall form a finish to the apron at 
 that end, and beyond it no apron need be constructed. 
 
 39. The connection between the groyne and the dain is to be made as the engineer in charge 
 may direct, as are all connections and finish in detail of the parts. 
 
23 
 
 MISCELLANEOUS PROVISIONS. 
 
 40. In the construction of this dam, it will be necessary to turn the waters of the stream 
 from their low- water channel in order to construct therein; and this work is to be done by the 
 contractor at his own risk and expense, without compensation other than provided for in pay- 
 ment for the main work. 
 
 41. The brush and trees necessary for the construction of this dam are to be cut off the sand- 
 covered flats adjacent to its site, and the Directors guarantee to the contractor the right to cut 
 and remove the same without compensation for damages or payment for the material; provided, 
 that in such cutting and transportation, the contractor constructs all necessary roads and cause- 
 ways, and openings in fences, etc., and exercises due diligence and care to avoid unnecessary 
 damage; and further provided, that the Directors will not be responsible for any damage occa- 
 sioned by reason of the escape of stock, or the inroads of stock upon crops or pastures which 
 may be occasioned by the openings in fences, made by the contractor, or in any way by the 
 occupation of premises by him. 
 
 42. The brush cutting shall be conducted under the direction of the engineer in charge, and 
 in' no case shall all of the brush be stripped from the land below the site of the dam; but belts 
 thereof, at least fifty feet in width, shall be left at five hundred feet intervals, and extending 
 across the general direction of the stream so far as it grows. 
 
 43. The rock necessary in the construction of this dam shall be quarried half on the north 
 side of the stream from the down stream face of the point against which the dam is to rest, at 
 such point as the engineer in charge may direct, and half on the southern shore of the river, in 
 the rocky point just above the dam site. 
 
 44. The Directors guarantee the contractor the right to quarry and remove this rock without 
 compensation for material, or damages under the same provision as heretofore enu'merated in 
 the matter of cutting and removing brushwood for the dam. 
 
 45. The Directors guarantee to the contractor the right of way for the transportation of all 
 material on such routes as may be reasonably practicable, and on conditions as respects liability 
 for damages, similar to those already inserted in the section concerning brush cutting. 
 
 46. All brusjh cut and all rock quarried in the prosecution of this work, and remaining 
 unused at its completion or forfeiture of contract, is to revert to the Board of Directors, and the 
 contractor is not to lay claim, after the work is done, to any peculiar privileges of right of 
 way, or right to material of any kind other than his plant of tools and appliances which may 
 be removed from the premises. 
 
 47. Whenever the word gravel is used in these specifications,, it is to be taken as meaning the 
 best material of the kind to be found along the line of the structure, or within 500 feet thereof; 
 it shall not contain more than 30 per cent, of sand, and must pass inspection of the engineer in 
 charge. 
 
 LAYING OUT AND MEASUREMENT OF WORK. 
 
 48. This work is to be staked out by the resident engineer, under the direction of the State 
 Engineer, and is to be carried forward to the satisfaction of the engineers and the Board of 
 Directors of the district. 
 
 49. Measurements for works of certain dimensions are given on the exhibits and schedule 
 hereunto appended, and made a part of these specifications as hereafter enumerated. Payment 
 is to be made on such measurements for the standard sizes shown, and for intermediate sizes 
 payment will be made upon dimensions of cross sections proportioned to the height of the dam 
 above the ground line in each ca*e. 
 
 50. All extra work of any class, except excavations to depths below the limit heretofore 
 specified (six feet), is to be done at contract prices upon the measurement thereof. 
 
 51. Measurement of work is to be agreed to by the contractor and resident engineer upon 
 each division thereof before it is laid in. 
 
 52. Work is only to be accepted and approved and taken off the contractor's hands upon the 
 final completion of the entire structure. 
 
 53. In case of any undue settling of any part of the dam after the completion of that part, 
 the integrity of the work is to be preserved in such manner as the State Engineer may specify 
 and the Board of Directors may direct, and consequent differences between the contractor and 
 the Board of Directors are to be made by the Directors and in their discretion. 
 
 54. The work is to be prosecuted from its two ends simultaneously, and with all due dili- 
 gence and dispatch, and brought forward in the manner and order directed by the engineer in 
 charge. 
 
 AMENDMENTS TO FOEEGOING SPECIFICATIONS, 
 Prepared at request of the Board of Directors, District No. 1, July 6, 1880. 
 
 55. The foregoing specifications are to govern the construction of the contemplated dam, 
 except, in case trees of proper size cannot be secured in sufficient number for the purpose within 
 2,000 feet of site of the work, when, after close examination, the Board of Directors may curtail 
 the dimension of the dam in cross section. 
 
24 
 
 
 
 56. And again, should the supply of small trees as called fot- in the specifications to be 
 found within 2,000 feet of the work prove to be insufficient to complete the structure to the 
 dimensions finally determined upon by the Board of Directors, the contractor may substitute 
 bundles or fascines of smaller trees or brush saplings, made and laid under the direction of the 
 engineer in charge. 
 
 57. The fascines are to be made where the brush is cut, in lengths proper to substitute for 
 the small trees called for in the specifications; are to be made in presses, as shown in a cut 
 accompanying these specifications, or in some way insuring equally good manufacture,- and 
 are to be firmly bound, at four-foot intervals, with No. 16 (Birmingham gauge) iron wire. 
 
 FASCINE CONSTRUCTION. 
 
 58. These fascines are to be substituted for the trees where designated by the engineer in 
 charge, are to be pegged down and together firmly, and treated in all respects as are the trees 
 in the structure; prodded, that the top course at" the upper edge, and that at the lower edge 
 of the dam's crest, and the course at the foot of the overfall shall be composed entirely of trees ^>f 
 the dimensions and otherwise as at first specified. 
 
 BIDS FOR THE WORK. 
 
 59. The work to be executed in completing this structure is classified as follows: 1 Exca- 
 vation for foundation; 2 Brush and timber ballasted; 3 Gravel backing; 4 Stone backing: 
 5 Stone weighting and protection of ends of the dam; 6 Earthwork embankment or levee at 
 south end of the dam. 
 
 60. Excavation. Includes removal and disposal of all material to be handled iu preparing a 
 formation for the dam and the auxiliary works. 
 
 61. Brush and timber, ballasted Includes the cutting and transportation of brush and tim- 
 ber, the excavation and transportation of gravel for ballast, the laying of these materials, and 
 completion of the structure composed of them as before specified. 
 
 62. Gravel backing Includes the excavation, transportation, and depositing of this material 
 as heretofore outlined. 
 
 63. Stone backing Includes the stripping and opening of quarries, excavation" transportation, 
 and laying of stone according to specifications and directions. 
 
 64. Stone weighting and protection Includes work as provided above under head x of "Stone 
 backing." 
 
 65. Earthwork embankments Includes the construction of an earthwork levee not over 1,200 
 feet long at south end of dam, containing about five cubic yards of material per linear foot. 
 The work to be done with scrapers and as directed by the engineer in charge. 
 
 Bids are desired for this work as follows : 
 
 66. For the excavation : Per cubic yard, measured in the pit. 
 
 67. For the brush and timber ballasted : Per cubic yard, measured in the work (predetermined 
 allowances for settlement not counted in.) 
 
25 .. ' J .; ;' :-:>/;'. ;...", 
 
 
 68. For gravel backing : Per cubic yard, measured in place on completion. 
 
 69. For stone backing : Per cubic yard, measured in place on completion. 
 
 70. Stone weighting and protection : Per cubic yard, measured in place on completion. 
 
 71. Earthwork embankment : Per cubic yard, measured on completion (predetermined allow- 
 ances for settlement not counted.) 
 
 SPECIFICATIONS FOB THE DAM AT SITE NO. 2, ON THE YUBA RIVER. 
 
 These specifications, so far as the composition and construction of the dam are concerned, are 
 substantially the same as those for the dam at site No. 1. 
 
 The points of difference are shown in the following synopsis of specifications for the dam at 
 site No. 2. 
 
 1. The proposed dam site No. 2 is two (2) miles below site No. 1. 
 
 2. The line is marked on the ground similarly to line No. 1, and on the map is shown as 
 "Line of proposed dam No. 2." 
 
 3. In the direct course the distance across the high-water channels and intervening flats of 
 the river is about 9,600 feet, and consequently the dam proper will be about this length. 
 
 Paragraphs 4 to 31, inclusive, are the same as in specifications for dam at site No. 1. 
 
 Paragraphs 32 to 36, inclusive, are omitted. 
 
 37. End finish : The ends of the dam are to be raised gradually, so that water will not run 
 over its crest within at least 100 feet of the ends proper, and these are to be joined with the 
 natural bank, or with earthwork embankments. 
 
 Paragraphs 38 and 39 are the same, with the exception that there must be a training wall at 
 both ends of the dam, at site No. 2. 
 
 Paragraphs 40 to 58, inclusive, are the same. 
 
 Paragraph 59, leave out "stone backing," and "stone weighting," and change numbering 
 to suit. 
 
 Paragraphs 60 to 62, inclusive, the same. 
 
 Paragraphs 63 and 64 to be omitted. 
 
 Paragraphs 65 to 68, inclusive, the same. 
 
 Paragraphs 69 and 70, inclusive, to be omitted. 
 
 Paragraph 71, the same. 
 
 SPECIFICATIONS FOB A DAM OF BRUSHWOOD AND GRAVEL ON BEAR BIVER. 
 
 These specifications are in all respects similar to those for the dam at proposed site at No. 2, on 
 Yuba River, with the exception that the site is described as being on a line directly across the 
 river from a point' 200 feet, more or less, above the head of the levee on the north side of what 
 was formerly known as Johnson's Crossing, and the probable length of the dam is about 
 6,000 feet. 
 
 The contracts for the erection of the dams were awarded on August 
 10th, the one on the Yuba River to Messrs. Rideout & Binney, of 
 Marysville, and that upon Bear River to Messrs. Doane & McBean, 
 of San Francisco. 
 
 The cost of the works was somewhat enhanced by the fact that the 
 contractors were, by the terms of tlieir contracts, required to com- 
 plete the structures within sixty days, the fear of approaching storms 
 precluding greater delay. A variety of causes combined to prevent 
 the completion of either structure within contract time, but fortu- 
 nately the work was finished before storms intervened. 
 
 It is too soon, however, to speak in the light of mature experience 
 of the effects to be produced by these dams. State Engineer Hall, 
 who has made their construction and availability a subject of patient 
 and persistent study, is sanguine as to the results to be experienced, 
 and his theories have the approval of such eminent engineers as 
 Colonel G. H. Mendell, United States Engineer, and Captain James 
 B. Eads, both gentlemen of world- wide celebrity in their profession, 
 and who have, in their capacity as Consulting Engineers, given this 
 work special attention. 
 
 Thus far the dams promise all that can be hoped for. They check 
 the flow of water and rid it of the heavier portion of its sand, which 
 has already accumulated to a considerable depth just above the 
 
 4 r 
 
structures, and the water thus relieved of its surcharged material, is 
 permitted to flow on with its scouring capacity greatly increased. 
 
 LEVEE WORK. 
 
 The work of constructing levees to confine the waters of the 
 Feather, Yuba, Bear, and Sacramento Rivers within their respective 
 channels, with a view to increase the scouring capacity of those 
 streams during flood periods, has been steadily pushed forward on 
 as large a scale as the funds at command would warrant. 
 
 The following table will show the amount and the purposes for 
 which money has been expended : 
 
 State Engineer Department Payroll $12,262 00 
 
 State Engineer Department Expenses 5,158 87 
 
 District Engineer Department Payroll 7,841 41 
 
 District Engineer Department Expenses 4,086 66 
 
 Assessors and Auditors of counties, in District 8,965 99 
 
 Advertising 1,025 50 
 
 Legal expenses, brush, &e 863 50 
 
 Salaries of Directors and Secretary 2,286 64 
 
 Office expenses 50 00 
 
 Printing, specifications, stationery, etc 326 65 
 
 Paid for work (per contract) . 320,321 18 
 
 Total .- $363,188 40 
 
 We have commenced suits for condemnation of land to be used 
 for storage of debris above the dams, and material of which said 
 dams are constructed, as provided for in section eleven of the Act 
 to promote drainage, and said suits are now in process of litigation. 
 
 CONCLUSION. 
 
 Difficult as has been the labor entered upon by the Directors, they 
 feel warranted by experience in declaring that during the progress 
 of their operations they have seen much to encourage the hope of 
 ultimate success. Obstacles that seemed insurmountable, have either 
 disappeared or proven less formidable than was supposed. Many 
 who, at the outset, doubted the feasibility of controlling the large 
 volume of mining debris constantly being sent down from the moun- 
 tain gulches, of restoring the regimen of the rivers, and teaching 
 those rivers to excavate their own channels, better informed, are 
 yielding to the belief that, by an intelligent and systematic treatment 
 of the whole problem, our navigable waters may be saved to com- 
 merce, the industries of the farmer and miner brought into such 
 relations that each may prosper without material injury to the 
 other, and the general welfare be promoted at an expense commen- 
 surate with the object to be obtained. 
 
 w! F.'KNOX, 
 
 NILES SEARLS,^ 
 .Board of Directors of Drainage District No. 1. 
 
 Attest : CHARLES M. COGLAN, Secretary. 
 
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