THE RESOURCES AGENCY OF CALIFORNIA p a r t m e n t of Wa ter Resources BULLETIN No. 107 ^ Fl ■^j^jj: RECOMMENDED WELL CONSTRUCTION >]■. f AND SEALING STANDARDS FOR PROTECTION GROUND WATER OUALITV^'lN WEST COAST BASIN LOS ANGELES COUNT' i I . .1 ;• SURFACE SEAL o o -f-'f AQIIIFER SEAL AUGUST 1962 •••■.I • ----I univers:tVJgp-gAliforn!A well destruction ja:i ^'^ . L f P " A "tJ V EDMUND G. BROWN Governor State of California WILLIAM E. WARNE Adminisfrafor The Resources Agency of California and D/rec/or Department of Water Resources stale of California THE RESOURCES AGENCY OF CALIFORNIA Department oF Water Resources BULLETIN No. 107 RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER OUALITY IN WEST COAST BASIN LOS ANGELES COUNTY AUGUST 1962 EDMUND G. BROWN Governor State of California LT^RARY e»Iirt:.4a;iTY Ol« CALIEOENIA DAVIS WILLIAM E. WARNE Adminiifro/or The Resources Agency of California and Director Department of Water Resources TABLE OF CONTENTS Page LETTER OF TRANSMITTAL Xi .ACKNOWLEDGMENTS xii ORGANIZATION xiii CHAPTER I. INTRODUCTION Authorization ^ Purpose and Scope of Investigation 2 Area of Investigation ^ CHAPTER II. GEOLOGY Geologic Divisions H Geologic History 13 Structure ^5 Sequence and Water-Bearing Characteristics of Sediments ... l6 Recent Series -^T Active Dune Sand 1? Alluvial Deposits 17 Semiperched Aquifer 1? Bellflower Aquiclude 1" Gaspur Aquifer l8 Pleistocene Series 19 Older Dune Sand 19 Lakewood Formation 20 Semiperched Aquifer 20 Bellflower Aquiclude 21 111 Page Gardena Aquifer 22 Gage Aquifer 23 San Pedro Formation 2U Fine-Grained Deposits 25 Lynwood Aquifer 25 Silverado Aquifer- 26 Pliocene Series 27 Pico Formation - Upper Division 27 Pico Formation - Middle and Lower Divisions .... 28 Pre-Pico Rocks 29 Geology and Ground Water 29 CHAPTER III. GROUND WATER HYDROLOGY Replenishment and Discharge of Ground V/ater 33 Subsurface Inflow 33 Deep Percolation S'* Precipitation 35 Stream Flow 35 Other Sources 35 Artificial Recharge 36 Discharge 37 Ground Water Movement 37 Semiperched Aquifer 38 Gaspur Aquifer 38 Gardena Aquifer 39 Gage Aquifer '+0 iv Page Lynwood Aquifer Ul Silverado Aquifer kl CHAPTER IV. QUALITY OF WATER Water Quality Criteria U3 Irrigation hk Municipal and Domestic ^5 Industrial ^6 Quality of Ground Water ^+6 Semiperched Aquifer ^ Gaspur Aquifer ^ Gardena Aquifer 50 Gage Aquifer 51 Lynwood Aquifer 52 Silverado Aquifer 53 Quality of Imported Water ^^ Impairment of Ground Water 55 Sources of Ground Water Impairment 56 Protection Against Rarther Impairment 57 CHAPIER V. WATER WELL CONSTRUCTION AND SEALING STANDARDS Areas of Recommended Sealing Standeurds 6I Santa Monica Bay Coastal Area - Zone 1 6I Inland Area - Zone 2 62 Los Angeles River Area - Zone 3 62 General Water Well Construction Standards 63 Location of Well Site 63 Casing 6h Casing Diameter Reduction 65 Joints 65 Perforations 65 Sealing Intervals of Strata Penetrated by Wells .... 66 Pressure Grouting Method 66 Liner Method 66 Surface Protection of Wells 68 Drilled Wells 68 Grouting Pipe Method 70 Pressure Cap Method 70 Gravel Packed Wells 70 Dug Wells 71 Well Pits 71 Pedestal and Pump 72 Sounding Tube and Air Vent Pipe 73 Water Quality Sampling 73 Disinfection 7^ Specific Water Well Construction Standards 75 Santa Monica Bay Coastal Area - Zone 1 75 Inland Area - Zone 2 75 Los Angeles River Area - Zone 3 75 Case I - Wells Producing from the Gaspur Aquifer or the Merged Gaspur and Gage Aquifers 76 vi Page Case II - Wells Producinf; from the Ga^e Aquifer 76 Case III - Wells Producing from the Lynwood and Silverado Aquifers 76 General Sealing Standards for Water Well Destruction .... 77 Specific Sealing Stajndards for Water Well Destruction .... 8l Santa Monica Bay Coastal Area - Zone 1 8l Inland Area - Zone 2 82 Los Angeles River Area - Zone 3 82 Case I - Well Producing from the Gaspur Aquifer or the Merged Gaspur and Gage Aquifers 82 Case II - Wells Producing from the Gage Aquifer . . 82 Case III - Wells Producing from the Lynwood and Silverado Aquifers 83 CHAPTER VI. SUMMARY OF FINDINGS AND CONCLUSIONS, WITH RECOMMENDATIONS Findings and Conclusions 85 Recommendations 86 TABLES Table No. Page 1 Analyses of Ground Water from Representative Wells in West Coast Basin Prior to December 19^. ... ^7 2 Analyses of Ground Water from Selected Wells in Semiperched Aquifer ^9 3 Analyses of Ground Water from Selected Wells in Gaspur Aquifer 50 h Analyses of Ground Water from Selected Wells in Gardena Aquifer 51 vii TABLES Table No. Page 5 Analyses of Ground Water From Selected Wells in the Gsige Aquifer 52 6 Analyses of Ground Water From Selected Wells in the Lynwood Aquifer 53 7 Analyses of Ground Water From Selected Wells in the Silverado Aquifer 5*+ 8 Analyses of Imported Water Used in West Coast Basin 55 9 Amount of Chlorine Compounds Required to Provide 50 ppm Free Chlorine for Each 100 Feet of Water-Filled Casing 7*+ FIGUEES Figure No. Page 1 Land Use for Selected Years in West Coast Basin 6 2 Water Use, 1933 to I96I, in West Coast Basin 9 3 Geologic Timetable and Generalized Stratigraphic Column in West Coast Basin 31 k Typical Methods for Sealing Intervals of Strata 67 5 Typical Surface Protection Peatvires 69 6 Typical Sealing Features of Destroyed Wells 78 PLATES Plate No. Title 1 Location auid Physiographic Features in West Coast Basin 2 Areal Geology in West Coast Basin 3 Generalized Geologic Sections A-A', B-B*, and C-C in West Coast Basin 1|- Areal Extent of the Gage, Gardena, and Gaspur Aquifers in West Coast Basin viii PLATES Plate No. Title 5 Contours on the Top of the Gaspur Aquifer in Dominguez Gap, West Coast Basin 6 Contours on the Top of the Gage Aquifer in Dominguez Gap, West Coast Basin 7 Contours on the Top of the Gage and Gardena Aquifers in West Coast Basin 8 Contours on the Top of the Lower Sealing Horizon in Dominguez Gap, West Coast Basin 9 Location and Status of Key Wells in West Coast Basin 10 Areas of Recommended Sealing Standards in West Coast Basin APPENDIXES Appendix Page A List of References A-1 B Definitions B-1 C Well Numbering System C-1 D Casing Requirements for Drilled and Dug Wells D-1 IX VILLIAM E. WARNE Director of i Water Resources ABBOn GOLDBERG hief Deputy Director EGINALD C. PRICE eputy Director Policy NEELY GARDNER Deputy Director Administration ALFRED R. GOLZE Chief Engineer EDMUND G. BROWN GOVERNOR OF CALIFORNIA WILLIAM E. WARNE ADMINISTRATOR RESOURCES AGENCY ADDRESS REPLY TO P. O. Box 388 Sacramento 2, Calif. THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES 1120 N STREET, SACRAMENTO September 11, 1962 Honorable Edmund G. Brown, Governor and Members of the Legislature of the State of California Los Angeles Kegional VJater Pollution Control Board Gentlemen: I am pleased to transmit to you Bulletin No. 10? of the Department of Water Resources, entitled "Recommended VJater Well Construction and Sealing Standards for the Protection of Ground Water Quality in VJest Coast Basin Los ivngeles County." The investigation was conducted under authority of Section 231 of the Water Code and at the request of interested agencies opera- ting in the county. This is one of a series of reports designed to formulate and recom- mend water well construction and sealing standards for particular localities of the state where regulation is deemed necessary for the protection of ground water ouality. In the West Coast Basin, Los Angeles County, where no such regulation exists, many water wells, which have been constructed improperly or sealed inadequately, are contributing to quality impairment of ground water by allowin;; interchange of water between aquifers. The report concludes that v/ater well construction ajid sealing standards must be employed. The standards presnnted are based on physical conditions and well construction practices found in the V/est Coast Basin Los Angeles County, and supplement the minimum standards presented in Bulletin No. 74, entitled "Recommended Minimum Well Construction and Sealing Standards for the Protection ol Ground Water Quality, State of California." The report recommends that the Los Angeles Regional V/ater Pollution Control Board, local agencies, local water producers, and water well drillers accept these standards, and apply them in a manner that will assist them in preserving and improving the quality of the common ground water supply. Sincerely yours, Director -XI- ACKNOWUEDGMENTS Valuable assistance and data used in this investigation were contributed by agencies of the Federal Government and of the State of California, by cities, counties, public districts, and by private companies and individuals. This cooperation is gratefully acknowledged. Special mention is made of the helpful cooperation of the following : Ausbum Oil Well Cementing Company B. J. Service, Inc. Baker Oil Tools, Inc. Baroid Division, National Lead Company California Department of Public Health Halliburton Company Los Angeles City Department of Water and Power Los Angeles County Flood Control District Los Angeles County Health Department Los Angeles Regional Water Pollution Control Board M. R. Peck and Sons McCullough Tool Company Roscoe Moss Company United States Geological Survey, Ground Water Branch Water Well Supply Company xii STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES EDMUND G. BROWN, Governor WILLIAM E. WARNE, Administrator, The Resources Agency of California and Director, Department of Water Resources ALFRED R. GOLZE', Chief Engineer JOHN R. TEERINK, Assistant Chief Engineer SOUTHERN DISTRICT James J. Doody District Engineer Lloyd C. Fowler Chief, Planning Branch The investigation leading to this report was conducted under the direction of David B. Willets Supervising Engineer Prepared under the supervision of Robert C. Fox Senior Engineering Geologist by Robert B. Gunderson Assistant Civil Engineer Eugene C. Ramstedt Assistant Civil Engineer Sanford L. Werner Assistant Engineering Geologist Karl H. Wiebe Assistant Engineering Geologist xiii CHAPTER I. INTRODUCTION Grovmd vater has played a dominant role in California's diversi- fied economic development; it has supported agricultural growth, permitted the establishment of high-density metropolitan areas, and encouraged the build-up of enormous industrial complexes. This is particularly true in Southern California where, for example, in the Coastal Plain of Los Angeles Covinty, ground water extractions presently (1961) supply about one-half of the total water put to beneficial use in that area. In the West Coast Basin, a major ground water basin in the Coastal Plain, ground water extractions have exceeded replenishment; as a result, ground water levels have declined below sea level. One result of these subsiding water levels is the intrusion of sea water into coastal por- tions of the basin, impairing water quality in that section. Other sources of impairment to ground water qusility within the West Coast Basin are sew- age and industrial wastes that have been improperly disposed of and poor quality ground water that has been allowed to commingle with good quality waters by improperly constnacted, utilized, suid destroyed water wells. This investigation was primarily concerned with ground water quaility inipairment directly attributable to such wells. It was conducted in the West Coast Basin because a continued supply of unimpaired ground water from that basin is of vital importance to the economy of the area. Based on an understanding of the many complex, interwoven roles of geol- ogy, hydrology, and well construction and sealing, recommendations are presented that, if followed, will alleviate or halt further impainnent of the vital ground water resources of the West Coast Basin by improperly constructed or sealed wells. Author! zation This report is the result of legislation enacted to protect the ground water quality from impairment by improperly constructed, sealed, or destroyed wells. This legislation has been codified in Section 231, Chapter 2, Division 1 of the California Water Code, as follows: "231. The department, either independently or in cooperation with any person or any county, state, federal or other agency, shall investigate and survey conditions of damage to quality of underground waters, which conditions are or may be caused by improperly constructed, abandoned or defective wells through interconnection of strata or the introduction of surface waters into underground waters. The department shall report to the appropriate regional water pollution control board its recom- mendations for minimum standards of well construction in any particular locality in which it deems regiilation necessary to protection of quality of underground water, and shall report to the legislatvire from time to time, its recommendations for proper sealing of abandoned wells." Purpose and Scope of Investigation The purpose of this investigation was to formulate water well construction and sealing standards for the West Coast Basin in Los Angeles County; when implemented, these standards will serve to protect groxind water quality from impairment caused by improperly constructed and/or improperly sealed wells. To achieve this purpose, all available geologic, hydrologic, and water quality data in the Department of Water Resources files and that collected from other agencies and individuals, and abstracts from nximer- ous reports concerning ground water in the coastal portion of Los Angeles County were reviewed and evaluated. These data were used to interpret surface and subsurface geologic conditions, ajid to locate beirriers to ground water movement; to evaluate ground water elevations and direction of groiind water movement; to locate sources of ground water replenishment; and to determine the ground water quality characteristics. Considerable effort was expended in a canvass of the basin to locate water wells and to determine their condition and characteristics. In addition, about 250 ground water samples were collected for mineral analysis to assist in the evaluation of water quality characteristics. Most of the geologic data concerning the ground water basin was obtained from previous investigations and reports. However, detailed geo- logic mapping of localized areas was performed to obtain specific informa- tion required in the formulation of well construction and sealing standards. This investigation also included a detailed study of local, state, and federal regulations relating to water well construction and/or sealing standards, and an evaluation of commonly accepted water well construction specifications. These specifications were developed through conferences with principal well drillers in Southern California and, integrated with the basic findings of this investigation, were used in the formulation of the recommended well construction and sealing standards presented herein. All supporting data used in this investigation are catalogued 8Lnd maintained in the basic data files of the department. For convenience of use, a list of pertinent references selected from these data sources is given in Appendix A. Appendix B gives a summary list of definitions of certain technical terms, augmenting those definitions given with first usage of the term in the text, euid Appendix C gives well location refer- ences and numbering methods used. Appendix D presents the casing require- ments for drilled and dug wells. -3- Area of Investigation The West Coast Basin is the most westerly portion of the Coastal Plain of Los Angeles County, as shown on Plate 1, "Location euid Physiographic Features in West Coast Basin"; it is about 19 miles long and averages about nine miles in width, occupying an area of approximately 102,500 acres. Approximately 80 percent of the surface area of the basin consists of a gently rolling, slightly eroded coastal plain which includes such physio- graphic features as the Torrance Plain, El Segundo Sand Hills, Dominguez Gap, and Long Beach Plainj partially encircling the basin are the border- ing hills which constitute the remainder of the basin surface. Surface elevations range from near sea level on portions of the coastal plain to 1,U80 feet above sea level in the Palos Verdes Hills, which are the most dominajit structural feature of the southwestera portion of the basin. These hills cover an area about nine miles long and four miles wide, trending in a northwest-southeast direction along the coastal portion of the basin. The El Segxindo Semd Hills extend northward from the Palos Verdes Hills along Santa Monica Bay. Reaching along the coast for about eleven miles, and extending inlsuid three to six miles, these sand hills obtain a maximum height of about I85 feet above sea level. The main body of the basin is a low lying, poorly drained plain whose original marine sxirface was partially eroded by an ancestral Los Angeles and San Gabriel River system. North of this plain lies Ballona Gap, a channel cut by an ancestral Los Angeles River, and occupied today by Ballona Creek. This gap is bordered on the south by the Ballona Escarp- ment, a precipitous bluff which rises 50 to 15O feet above Ballona Creek, and forms the northern boundary of the West Coast Basin. The eastern boundary of the coastal plain is marked by a discon- tinuous series of low rolling hills which extend in a northwest-southeast direction, and form the eastern boundary of the West Coast Basin. Extend- ing in order to the southeast and the Los Angeles-Orange County line are the Baldwin Hills, Rosecrajis Hills, Dominguez Hill, Signal Hill, and Bixby Ranch Hill, 'fhese hills are the surface expression of a series of faults and folds called the Newport -Ingle wood uplift. Flowing southward between Dominguez Hill and Signal Hill, the ancestral Los Angeles and San Gabriel River system cut another channel through the coastal plain. This ancestral channel was later backfilled with alluvium, smd is known today as Dominguez Gap. The Los Angeles River pres- ently flows through this gap to San Pedro Bay which adjoins the southern boundary of the basin. Within this basin today is a highly urbanized complex of large residential tracts interspersed with numerous industrial developments and some small agricultural acreages. This -was not always so, for as recently as 25 years ago, the West Coast Basin was an area of small suburban communi- ties surrounded by truck farms, orchards, large ranches, and grazing lands. The change in land use in West Coast Basin during the period 1932 to i960 is shown graphically on Figure 1. As illustrated, the irrigated agricultural acreage decreased from about 22,100 acres in 1932 to about 7,000 acres in 196O. During the same period, the land devoted to urban- suburban use increased from about 33>8CK) acres to about 86,300 acres. The change in population in the West Coast Basin is just as sig- nificant as the change in land use. In 1930, the population of the West Coast Basin was about 26U,000. In 19^0, this figure had increased to •5- FIGURE I 90 80 70 if) UJ q: ^60 u. o to Q z 50 < CO O r ?40 < (O 30 o or 20 10 URBAN - SUBURBAN USE AGRICULTURAL USE NOTE: TOTAL GROSS AREA IS 102,500 ACRESj AREA OTHER THAN URBAN-SUBURBAN AND AGRICULTURAL IS UNDEVELOPED m 1932 1942 1950 1955 I960 YEAR LAND USE FOR SELECTED YEARS IN WEST COAST BASIN 317>000, and by 1950, under the impetus of a wartime influx, the total population had increased to about 600,000. During the following eleven- year period, from April 1950 to April I96I, the population had increased from 600,000 to just over 1,000,000. These changes in land use and the population growth resulted in lajrge increases in the demands for water as compared with those of the pre- ceding decades. Prior to 19'*-9> almost all of the water in excess of direct precipitation used in the West Coast Basin came from the ground water resources \inderlying the basin. The heavy volume of water extracted to meet the demetnds caused overdraft conditions in the basin, leading to prob- lems such as sea-water intrusion in the coastal areas. In the early 1900's when small eunounts of ground water were being extracted, ground water levels were above sea level throughout the West Coast Basin. Along the western edge of the Newport -Ingle wood uplift, ground water levels were 30 feet above sea level; northeast of the Palos Verdes Hills, near the Torrance -Wilmington anticline, ground water levels were more than kO feet above sea level. The use of ground water increased, ajid ground water levels dropped. By 1920, ground water levels at many wells had dropped below sea level, and by 1932, ground water levels were below sea level throughout most of the West Coast Basin. The decline continued until 1955 when a voluntary reduction in extractions by a number of pumpers in the West Coast Basin permitted the ground water levels to recover as much as ten feet in some parts of the basin. However, they vere still below sea level throughout most of the basin. Since 1955, vater levels have declined only a small amount. As a consequence of declining water levels, vater from wells adjacent to the coast began to deteriorate in quality and over the years the area underlain by degraded ground water has steadily increased. Along Sajita Monica Bay, wells were being abandoned prior to 1920 because of ex- cessive chloride concentrations. By 1932, the entire coastal area along Santa Monica Bay and a portion of the basin along San Pedro Bay near Long Beach were being intruded by sea water. By I96I, the coastal area under- lain by ground water containing a chloride concentration of more than 5OO parts per million extended inland about one and one-half miles along Santa Monica Bay. Figure 2 indicates that local ground water extractions for aigri- culture and urban-suburban use totaled about 35>000 acre-feet in 1933 * including about 17,000 acre-feet for agriculture. By 1953, local ground water extractions had increased to 90,000 acre-feet; of this amount, water for irrigation purposes had decreased to about 10,000 acre-feet. By I96I, ground water extractions had diminished to about 61,000 acre-feet with about 6,000 acre-feet being used for irrigation. Because of the serious nature of the overdraft on the ground water resources of the basin, it has been necessary to import water to relieve the demands on the local ground water. The major source of im- ported water is the Colorado River, and water is imported from there through the facilities of The Metropolitan Water District of Southern California. This water is delivered to member agencies including the City of Long Beach, City of Los Angeles, City of Torrance, and West Basin Municipal Water District, for distribution. Water is also imported from the Owens and Mono Basins through the facilities of the City of Los Angeles; -8- YEAR WATER USE, 1933 TO 1961, IN WEST COAST BASIN FIGURE 2 the Dominguez Water Corporation, City of Long Beach, and Southern California Water Company, all import water from the Central Basin. During the fiscal year 19^9-50, when imported Colorado River water became available, about 1,560 acre-feet were brought into the basin, but by 196O-6I, this figure had increased to over 93,600 acre -feet. As shown on Figure 2, total water importations into the West Coast Basin increased from approximately 15,000 acre-feet in 1933 "to over 151,000 acre-feet in 196I. -9- Despite these Increasing volumes of imported water, the ground water resources continue to provide a large portion of the water put to beneficial use in the West Coast Basin. Extractions by the numerous wells in the basin continue to contribute to overdraft conditions. Paradoxi- cally, the same wells which are used to extract ground water may also contribute to the impairment of water quality in the ground water reser- voir by serving as conduits to interconnect the various aquifers. The discussion of the West Coast Basin geology in Chapter II will indicate how this interconnection exists eind will provide information on some of the other factors on the impairment of ground water quality which must be con- sidered in any effective remedial program. -10- CHAPTER II. GEOLOGY This chapter presents the location, extent, physical character, structure, and geologic history of the water-bearing and significant nonwater-bearing deposits occurring in the West Coast Basin. The surface and subsurface geology reported herein is based on field surveys and office studies, including review of published reports, with emphasis given to the nature and extent of aquifers and the confin- ing horizons of low permeability which affect well construction and sealing standards. In addition, mention is made of the areas where hydraulic continuity was found to exist between the ground surface and underlying aquifers, or between aquifers. Geologic Divisions In order to discuss the geology of the West Coast Basin, it is necessary to utilize a system of classifying names for divisions of the geologic time scale, and a similar system of names for the geologic material which accumulated or developed during cori-esponding units of the time scale. The primary divisions of the geologic time scale are based on changes in life forms, except that the inaiiguration of the latest major division is based on the advent of glacial activity. Within each of these extensive primary divisions are the smaller geologic time divisions, gen- erally based on major changes in the earth's structure. The generally recognized geologic-time units, in order of decreasing magnitudes of time-span are: era, period, epoch, and age. These geologic-time units -11- and their common names, pertinent to the discussions of the West Coast Basin geology, are given on Figure 3 at the end of this chapter. Using this type of classification, the San Pedro formation, for example, can be described as having been deposited during the early por- tion of Pleistocene time, or to be of early Pleistocene age , laid down during the Pleistocene epoch , of the Quaternary period, in the Cenozoic era . It will be seen from Figure 3 that each successively larger geologic-time unit incorporates all of the preceding smaller divisions. Corresponding to these geologic-time units are the time- stratigraphic units, used to designate the rock material vrtiich accumu- lated or was deposited during an associated geologic-time unit. Ranked in decreasing order of magnitude, these divisions are: system, series, and stage. Thus, as shown on Figure 3, the San Pedro formation is part of the lower Pleistocene stage , which in turn is part of the Pleistocene series of the larger Quaternai^- system . As in the geologic-time units, each successive time-stratigraphic unit encompasses all preceding smaller units. It should be noted that a definite correlation exists between the "early" and "late" designations used with subdivisions of geologic- time units (e.g., early Pleistocene), and the "lower" and "upper" desig- nations used with corresponding time-stratigraphic units (e.g., lower Pleistocene). When using geologic-time units, the San Pedro formation is designated as early Pleistocene in age; however, in terms of time- stratigraphic units, the San Pedro formation would be designated as a lower Pleistocene deposit. Thus, "early" would normally be equated with "lower," and "late" normally equated with "upper." -12- The accumulations of rock material in the time-stratigraphlc units may also be further subdivided into mappable assemblages of strata, distinguished and identified by objective physical criteria observed in the field or in subsurface studies; these subunits are called groups, formations, and members. In ground water geology, for example, aquifers are called water-bearing members. Geologic History Deposition, compaction, metamorphism, and erosion of Jurassic rocks mark the earliest recorded phase of the geologic history in the West Coast Basin. Younger sediments of Cretaceous and early Tertiary age have not been encountered in the West Coast Basin; this suggests that either this area was a structural high \rtiich received no sediments, or that any sediments which may have been deposited were later removed by erosion. The area was intermittently covered by marine seas from middle Miocene time through early Pleistocene time, and a thick section of marine Miocene, Pliocene, and Pleistocene sediments was deposited. The principal water-bearing materials were deposited in the West Coast Basin during the Pleistocene and Recent epochs. A shallow marine sea covered a large portion of the Coastal Plain of Los Angeles County and all of the area of the West Coast Basin during most of early Pleistocene time. Numerous streams carrying debris from the inland highlands deposited their load on flood plains, in lagoons near the shore line, and in a shaJ-low offshore marine environment. The offshore materials were probably reworked and redistributed by the action of longshore currents. The heterogeneous materials deposited throughout early Pleistocene time are known as the San Pedro formation. This -13- formation was folded and locally faulted toward the close of early- Pleistocene time along the crest of the Newport -Inglewood uplift and in the PelLos Verdes Hills. Gentle folding also occurred along the Gardena syncline, Wilmington-Torrance anticline, and the Lomita sjmcline. Structural features are shown on Plate 2, "Areal Geology in West Coast Basin." Few of the present day physiographic features, delineated on Plate 1, existed in the West Coast Basin prior to late Pleistocene time. The West Coast Basin was a low coastal plain during part of late Pleistocene time. Minor transgressions of the sea occurred inter- mittently and debris from the bordering highlands was deposited in a shallow marine sea and in brackish water lagoons. These deposits form the Lakewood formation which was formerly known as the "unnamed upper Pleistocene deposits." During the late Pleistocene, an ancient river, responding to lowered sea levels, entrenched a channel through the Rosecrans Hills and thence across the West Coast Basin to the sea. This trench was then backfilled with sediments when the level of the sea subsequently rose during a major interglacial interval. Near the close of the Pleistocene epoch, at the beginning of the last glacial interval, the level of the oceans once again declined and sand deposits accumulated along the shores as vast sand dunes. The ancestral Los Angeles and San Gabriel River system entrenched a chsuinel through the Newport -Inglewood uplift between Dominguez Hill and Signal Hill and across the West Coast Basin to its new lower base level. With still another rise of sea level in post-glacial, or Recent time, sedi- ments were deposited within this channel. ■Ik. structure The major structural features within the West Coast Basin are shown on Plate 2, and on Plate 3> "Generalized Geologic Sections A-A', B-B', and C-C, in West Coast Basin." Folding and associated faulting have formed the dominant structural features throughout the West Coast Basin. One of the major structural features in the area is the Newport-Inglewood uplift which forms the eastern boundary of the West Coast Basin. This uplift is marked by a series of low anticlinal folds and en echelon faults, repre- sented by the Baldwin, Rosecrans, Dominguez, SignaG., and Bixby Ranch Hills, and the Inglewood-Potrero, Avalon-Compton, Cherry Hill, Reservoir Hill, and Seal Beach faults. From the Miocene epoch to the present, continuous deformation has occurred along this zone of weakness, forming a partial bari-ier to the movement of ground water in the Pleistocene and Pliocene sediments. However, faulting and folding have not obstructed movement of ground water in the Recent deposits. Coastward from the Newport-Inglewood uplift. Tertiary and Quaternary deposits are faulted and folded into a complex basin structure. The Pleistocene aquifers dip toward the Gardena syncline which flanks the Newport-Inglewood uplift from Long Beach to Ballona Gap. Along the western flank of the syncline, these deposits are offset in the northern part of the basin by the Charnock fault. West of this fault, the water- bearing deposits rise toward the northwest with a gentle slope. In the southern portion of the West Coast Basin, west of the Gardena syncline, the Pleistocene deposits are deformed over the Torrance-Wilmington anti- cline and Lomita- Wilmington syncline, and then sharply folded along the ■15- Gaffey anticline and syncline along the northeastern edge of the Palos Verdes Hills. The Palos Verdes Hills, an isolated structural highland, are composed predominantly of nonwater-bearing Tertiary and Jurassic rocks. The base of the northeastern slope of the Palos Verdes Hills approximates the southwestern limit of the water-bearing sediments in the West Coast Basin. Sequence and Water-Bearing Characteristics of Sediments In the West Coast Basin, ground water occurs in aquifers com- posed of sand and gravel deposits of late Tertiary and Quaternary age. Usually these aquifers are partially or completely separated from one another by variable thicknesses of relatively impermeable strata termed aquicludes. Nearly all of the aquifers and aquicludes found within the West Coast Basin occur within formations of either the Recent series or the Pleistocene series, with the exception of the Bellflower aquiclude and the semiperched aquifer which occur in both the Recent and Pleistocene deposits. Therefore, the Bellflower aquiclude and the semi- perched aquifer are discussed under both the Recent series and Pleistocene series. The deposits in the West Coast Basin are described on the fol- lowing pages from youngest to oldest, or from the surface downward, and their water-bearing characteristics are also presented. Areal geology and generalized geologic sections of the West Coast Basin are shown on Plates 2 and 3* The sequence of sediments is shown in Figure 3> >rtiich also includes the nomenclature used in prior reports. -16- Recent Series The Recent series in the West Coast Basin, as described in this report, is divided into active dune sand and alluvial deposits, which in turn are subdivided into the semiperched aquifer, Bellflower aquiclude, and Gaspur aquifer. Active Dune Sand . The sand dunes which comprise the coastal portion of the El Segundo Sand Hills extend as a narrow strip along Santa Monica Bay from Ballona Gap to Redondo Beach. These windblown deposits are generally less than 70 feet thick and consist of fine to medium- grained, clean, well sorted, ^rtilte or grayish sands of uniform texture. The dune sands generally occur above the zone of saturation and conse- quently are not considered to be a part of the ground water reservoir. However, because these deposits are highly permeable, precipitation and runoff are reeuiily absorbed by them and transmitted to the underlying older dune sand which is described later under the Pleistocene series. Alluvial Deposits . The Recent alluvial deposits are composed of lenticular beds of gravel, sand, silt, and clay which were deposited on broad flood plains, and in the lagoons and stream channels of the West Coast Basin. These sediments comprise the semiperched aquifer, Bellflower aquiclude, and the Gaspur aquifer. These deposits occur along the Los Angeles River and adjacent to the Dominguez Channel. Other Recent deposits accumulated southeast of Redondo Beach, and in the vicinity of Gardena are not discussed herein. Semiperched Aquifer. The semiperched aquifer, deposited during the Recent epoch, occurs only in Dominguez and Alamltos Gaps. It ■IT- consists of sands, sllty sands, silts, and clays deposited in alluvial and lagoonal environments. No wells are known to extract water from the Recent semiperched aquifer. Available data indicate that water levels in the semiperched aquifer are above water levels in the Gaspur aquifer. Bellf lower Aquiclude. The Bellf lower aquiclude, deposited during the Recent epoch, occurs in Domlnguez Gap and may exist in Alamitos Gap. It consists of alluvial and lagoonal materials deposited along the Los Angeles and San Gabriel River system. The aquiclude is composed mainly of sediments ranging from clays through sandy silts with lesser sunounts of sand and gravel. The Bellflower aquiclude separates the semiperched and Gaspur aquifers, and restricts verticeLL movement of water between them. Gaspur Aquifer. Underlying the Bellflower aquiclude in the vicinity of the Los Angeles River are medium to coarse-grained ssukL, gravel, and cobble deposits designated collectively as thfe Gaspur aquifer. The Gaspur aquifer is shown on Plate k, "Areal Extent of the Gage, Gardena, and Gaspur Aquifers in West Coast Basin," and Plate 5> "Contours on the Top of the Gaspur Aquifer in Dominguez Gap, West Coast Basin." The Gaspur aquifer was deposited by ancestrsLL streams within channels which had been entrenched into the coastal plain during the last glacial interval. Much of the Gaspur aquifer was deposited upon rela- tively impermeable upper Pleistocene sediments, although in certain areas the aquifer is in hydraulic continuity with the underlying Gage aquifer, as shown on Plate 6, "Contours on the Top of the Gage Aquifer in Dominguez Gap, West Coast Basin." -18- The Gaspur aquifer is not structurally affected by the Neyport- Inglevrood uplift, and there is no known restriction to ground water move- ment across the uplift. This aquifer has been traced for about 23 miles from the Whittier Narrows and the Los Angeles Narrows, southward across Central Basin to Terminal Island in the West Coast Basin, vrtiere data suggest that it also extends beneath San Pedro Bay. In the West Coast Basin, the Gaspur aquifer averages 50 to 6o feet in thickness, and is about one and one-half miles wide and six miles long. Many wells yielding from 200 to 1,500 gallons per minute have extracted ground water from this highly permeable aquifer throughout its reach in the West Coast Basin. Pleistocene Series Sediments of Pleistocene age in the West Coast Basin wete deposited in shallow marine, littoral, and continental environments. These deposits consist chiefly of unconsolidated sands, sandy silts, silts, and clays with interbedded water-bearing sands and gravels over- lying semiconsolidated sands, silts, and clays of Pliocene age. The Pleistocene series includes the older dune sand and the Lakewood forma- tion of late Pleistocene a^e, and the San Pedro formation of early Pleistocene age. Older Dune Sand . The sand dunes comprising the major portion of the El Segundo Sand Hills cover an area two to five miles in width and about thirteen miles in length. They underlie and are well exposed east of the sand dunes of Recent age. The older dune sand consists of fine to medium-grained sand with minor amounts of gravel, sandy silt, and clay. -19- These sand dunes range up to 200 feet in thickness and exhibit thin, irregular, relatively dense cemented layers near the surface. The older dune sand consists generally of three zones: a deeply weathered surface, an intermediate horizon of clean beach sands and gravels, and a lower horizon of relatively fine-grained materials. The intermediate sands and gravels may be equivalent to the semiperched aquifer of the Lakewood formation, but are included with the older dune sand for convenience. These dune sands originally were beach deposits; apparently, as sea level declined at the beginning of the last glacial interval they were exposed to the wind and blown inland. The shape of the original sand dunes has been modified by deep weathering and the growth of vege- tation. Because of weathering and consolidation, the older dune sand is less permeable than the active dune sand, and data indicate that the limited quantity of water found in the basal portion of the older dune sand moves seaward because of the seaward slope of the top of the Bellf lower aquiclude. Lakewood Formation . The Lakewood formation contains, in down- ward succession, portions of the semiperched aquifer and Bellflower aquiclude, the Gardena aquifer, and the Gage aquifer. Semiperched Aquifer. The semiperched aquifer, of late Pleistocene age, occurs throughout the West Coast Basin above the Bellflower aquiclude. As discussed previously, this aquifer also occurs in deposits of Recent age. The Pleistocene portion of the semiperched aquifer includes the terrace cover, the Palos Verdes sand, and other miscellaneous sediments. -20- A deeply weathered layer covers much of the surface of the West Coast Basin. This cover consists of up to 20 feet of reddish-colored sand and silty sand. In the southwestern part of the Torrance Plain, both the weathered layer and marine sands form the upper Pleistocene portion of the semiperched aquifer. The marine sands generally consist of silty seinds with thin gray or brown sand and gravel layers. Where present in the Torrance Plain, the marine sands are generally less than five feet thick but are known to have a thickness greater than 30 feet in other portions of the basin. The semiperched aquifer contains little available ground water in the northern part of West Coast Basin. In the central and southern part of the basin these sediments are of sufficient permeability to yield water to wells; however, the water is usually of poor quality. This aquifer is of little importance as a source of ground water, but it may be a source of impairment if its poor quality ground water is allowed to percolate to the underlying aquifers. Bellf lower Aquiclude. The Bellf lower aquiclude, formerly known as the "clay cap," underlies the semiperched aquifer of late Pleistocene age; it occurs throxoghout a major portion of the West Coast Basin, but it is absent along Santa Monica Bay, at the base of the north- east slope of the Palos Verdes Hills, and in other local areas. It con- sists of a heterogeneous mixture of fluvial, lagoonal, and marine sedi- ments composed of clays and silty clays, with lenses of sandy and gravelly clays. Its high silt and clay content restricts the vertical movement of ground water. This aquiclude attains a maximum thickness of •21- about 200 feet along the center and east flank of the Gardena syncline, between the City of Gardena and the City of Inglevrood. Gardena Aquifer. The Gardena aquifer varies in width from approximately one and one-half to four and one-half miles. It spans a distance of about eight miles within the West Coast Basin and extends into the Central Basin, as shown on Plate 7, "Contours on the Top of the Gage and Gardena Aquifers in West Coast Basin." This aquifer is gener- ally composed of sand and gravel layers with a few discontinuous lenses of sandy silt and varies in thickness from kO feet to a maximum of l6o feet. The stratigraphic position and physical features of the Gardena aquifer suggest that during the closing stages of the deposition of the Gage aquifer, a lowering of sea level occurred, and an ancestral river incised a channel into the Gage aquifer, and through it into the under- lying aquifers in the vicinity of Redondo Beach. A later rise in sea level resulted in the deposition of the coarse fluvial materials which comprise the Gardena aquifer in this channel. These events resulted in the mergence of the western end of the Gardena aquifer with the under- lying Lynwood and Silverado aquifers of the San Pedro formation. It also resulted in the northern and southern margins of the Gardena aquifer being placed in hydraulic continuity with the Gage aquifer. In the central part of the West Coast Basin the Gardena aquifer is separated from the underlying aquifers of the San Pedro formation by 55 to 130 feet of fine-grained materials. The Gardena aquifer is arched across the Newport-Inglewood uplift and appears to be displaced by the Avalon-Compton fault, a feature ■22- of the uplift. This feature appears to exert a partial barrier effect on the movement of ground water in the Gardena aquifer. The highly permeable Gardena aquifer is tapped by many wells in the vicinity of Gardena. Wells producing from this aquifer yield from 100 to 1,300 gallons per minute. Gage Aquifer. The Gage aquifer is the oldest member of the Lakewood formation. It extends throughout most of the West Coast Basin and across the Newport-Inglewood uplift into the Central Basin. This deposit accumulated at the beginning of late Pleistocene time and appears to have been deposited in a shallow marine sea which fluctuated across the coastal plain. The Gage aquifer is composed of sand contain- ing some gravel and thin beds of silt and clay and varies in thickness from 20 feet along Santa Monica Bay to 160 feet near Torrance. In the vicinity of Hawthorne and southeast of Dominguez Hill, the sands thin or grade laterally into silts and clays. The areal extent of the Gage aquifer is shown on Plate k and the elevation of its upper surface is indicated on Plate 7. This aquifer was designated as the "200-foot sand" in prior reports. Along the north flank of the Palos Verdes Hills, and adjacent to the coast along Santa Monica Bay, the Gage aquifer merges with aqui- fers of the underlying San Pedro formation resulting in direct hydraulic continuity between these aquifers. Inland, however, the Gage aquifer is separated from the lower aquifers eilong the Gardena syncline by as much as 230 feet of silts and clays. As previously noted, the Gage aquifer was eroded in the central portion of the West Coast Basin and the incised channel created was -23- backfilled vrith coarse sediments known as the Gardena aquifer (see Section C-C, Plate 3)« As a result of these processes the northern and southern sides of the Gardena aquifer are in direct hydraulic continuity with the Gage aquifer. In the southern portion of the West Coast Basin, the Gage aqui- fer underlies the Gaspur aquifer and in seversLL areas is merged with this overlying aquifer (Plate 5)« The Gage aquifer is arched and thins as it crosses the Newport- Inglewood uplift. Ground water movement is locally affected by features of that uplift. The Gage aquifer is not offset by the Chamock fault which appears to affect only the deeper aquifers. The Gage aquifer is a confined aquifer of moderate to low per- meability. Yields to wells from this aquifer are variable and generally low in comparison to the other main aquifers in the basin. San Pedro Formation . The San Pedro formation includes all de- posits of early Pleistocene age and consists of an upper fine-grained deposit of variable thickness, a sand and gravel portion known as the Lynwood aquifer, previously called in earlier reports, the "i*-00-foot gravel, " and the Silverado aquifer, an extensive coarse sand and gravel basal portion. This formation varies in thickness throxoghout the West Coast Basin because of deformation which occurred during and after deposition, and subsequent erosion of elevated areas. The thickest section occurs in th6 Gardena syncline where it varies from UOO feet near Ballona Gap to at least 1,000 feet near Dominguez Gap. .2k. Fine-Grained Deposits. The upper portion of the San Pedro formation comprises an unnamed aquiclude consisting of a series of rela- tively fine-grained sediments. These sediments occur throughout the major portion of the West Coast Basin and extend inland from the coast over the crest of the Newport -Ingle wood uplift. Their lithology is extremely variable, consisting of bluish-gray clay, silt, and sandy silt with occasional sand lenses. The major portion of this deposit is con- sidered to be of marine origin. In Dominguez Gap it appears to be thinner and exhibits much less continuity than elsewhere within the West Coast Basin. These deposits, because of their limited permeability, restrict vertical percolation between aquifers. In Dominguez Gap, this aquiclude constitutes part of the sealing horizon as shown on Plate 8, "Contours on the Top of the Lower Sealing Horizon in Dominguez Gap, West Coast Basin." Lynwood Aquifer. This aquifer occurs throughout most of the West Coast Basin and extends inland across the Newport- Inglewood uplift into the Central Basin. The Lynwood aquifer is composed mainly of sand and gravel with occasional lenses of sandy silt to fine sand. It ranges in thickness from 100 feet in the vicinity of Gardena to a maximum of about 200 feet across the western portion of the Wilmington anticline. The Lynwood aquifer merges with the Silverado aquifer along the northeast margin of the Palos Verdes Hills, along the entire Santa Monica Bay portion of the West Coast Basin, and in local areas on the eastern side of the Newport -Inglewood uplift. In the vicinity of the Gardena syncllne the I^wood aquifer is generally separated from the underlying Silverado aquifer by extensive ■25- fine-grained deposits of variable thickness. These fine-grained deposits thin markedly in the westward direction of mergence of the Lynwood aquifer and the underlying Silverado aquifer. Within the West Coast Basin, the Lynwood aquifer is offset by the Chamock fault which acts as a partial barrier to ground water move- ment. This aquifer is arched and faulted across the Newport -Ingle wood uplift which also forms a partial barrier to the movement of ground water in this aquifer to and from the Central Basin. The Lynwood aquifer is highly permeable and numerous irrigation wells produce ground water from it. Yields of 500 to 600 gallons per minute have been reported where the aquifer is only about one-fourth its maximum thickness. Silverado Aquifer. The Silverado aquifer underlies most of the West Coast Basin, cropping out on the northern slope of the Palos Verdes Hills and on the southern slope of the Baldwin Hills, and extends across the Newport -Ingle wood uplift into the Central Basin. It is a continuous body of fine to coarse-grained, blue-gray sand and gravel that was deposited in a shallow, open sea by streams carrying sediments from the high inland areas. Along the axis of the Gardena syncline, this aquifer varies in thickness from about 2^0 feet near the Ballona Escarpment to about 500 feet northeast of Wilmington. The Silverado aquifer is merged with the overlying lynwood aquifer along the coast from Ballona Gap to Redondo Beach, and along the north flank of the Palos Verdes Hills. In the Redondo and Hermosa Beach areas, the merged Silverado aquifer is in hydraulic continuity with the overlying Gardena aquifer, and is merged with the Gage aquifer from -26- Hermosa Beach to Ballona Gap. The merged Silvereido aquifer is also in continuity with the Gage aquifer along the north flank of the Palos Verdes Hills. The Silverado aquifer is offset by the Charnock fault which acts as a partial barrier to the movement of ground water in this aquifer. It is generally deformed to a greater degree than the overlying Lynwood aquifer and its reach across the Newport -Inglewood uplift is warped and faulted, creating a partial barrier to ground water movement. The highly penneable Silverado aquifer yields large quantities of water to wells which generally produce from 200 to if, 000 gallons per minute . Pliocene Series Recent and Pleistocene deposits are underlain throughout most of the West Coast Basin by consolidated and semiconsolidated sediments of Pliocene age. For the purpose of this report, the Pico formation of late Pliocene age has been sepaxated into three subdivisions based mainly upon water-bearing characteristics. Pico Formation - Upper Division . The upper division of the Pico formation averages 1,000 feet in thickness and consists of inter- bedded, semiconsolidated sand, micaceous silt, and clay members of proba- ble marine origin. It is relatively thin adjacent to the north flank of the Palos Verdes Hills but thickens to approximately 1,800 feet in the area beneath the Dominguez Hill. Fresh water sands averaging 200 to UOO feet in thickness and occasional lenses of gravel are interbedded with relatively impermeable -27- silt and clay layers. Beneath the Baldwin Hills the upper division of the Pico formation consists essentially of silt deposits. Limited data from deep vater wells, oil wells, and exploration holes indicate that waters derived from the sand menibers of the upper division of the Pico formation are essentially fresh and should be suitable for certain industrial uses. The transition zone between the fresh ground water and the underlying saline ground water seems to correspond roughly with the base of the upper division of the Pico for- mation, except in the vicinity of the Potrero fault southeast of Inglewood, in the Redondo Beach area, and near the Torrance and Wilmington oil fields. In these four areas the transition zone rises as much as i»^00 feet above the base of the upper division of the Pico forma- tion. In the Torrance-Redondo Beach area, electric logs of oil wells indicate a wedge-shaped zone of saline water near the top of the upper division of the Pico formation with fresh waters above and below. Pico Formation - Middle and Lower Divisions . The middle and lower divisions of the Pico formation consist of interbedded sandstone, siltstone, claystone, and shale members ranging from 1+00 to 1,700 feet in thickness. Throughout most of West Coast Basin these sediments are far below the depths reached by the deeper water wells. However, oil well data indicate that portions of these sediments may be sufficiently permeable to transmit water in usable quantities, although this water is generally too saline for most beneficial purposes. ■28- Pre-Pico Rocks Tertiary sediments of early Pliocene and Miocene age underlie all of the West Coast Basin and crop out in the Palos Verdes Hills. These deposits composed of sandstone, siltstone, claystone, mudstone, sheile, diatomite, and conglomerate vary from i«-,800 to ll»-,000 feet in thickness. They are essentially nonwater-bearing, although sandy por- tions contain saline or brackish water. In the Palos Verdes Hills, outcrops of volcanics of Miocene age and the Catalina schist of Jurassic age occur. Logs of deep oil wells indicate that the Catalina schist underlies the Tertiary sediments throughout a large portion of the basin. The schist and volcanics in the Palos Verdes Hills are essentially nonwater-bearing . Geology and Ground Water The brief discussions of the geology of the West Coast Basin given in this chapter are intended to be a point of departure for the remainder of the investigation, providing a description of the physical framework within \riiich the various elements of ground water supply operate. The relationships of these elements and the effect of the geologic characteristics of the basin on them will be described in suc- ceeding chapters. -29- FIGURE 3 PREVIOUS AQUIFER NAMES adopted interim standards for the upper limits of certain mineral constitu- ents in drinking water. Temporary permits to supply water to domestic water systems failing to meet the above recommended upper limits may be issued provided the concentrations of the mineral constituents in the following tabulation are not exceeded: -U5- Maximum concentration in ppm Constituent Permit* Temporary permit Totsil Dissolved Solids 500 (1000) 1500 Sulfate (SOi^) 250 (500) 600 Chloride (Cl) 250 (500) 600 Magnesium (Mg) 125 (125) 150 * Nuiribers In parentheses are maxiimm permissible to be used only vhere other more suitable water is not available in sufficient quantity for use in the system. Industrieil It is not feasible to organize into a single tabiilation the water quality criteria for water used in each of the many different industrial processes. However, two of the uses common to many industries, are the use of cooling water and boiler feed make-up water. A dominant factor in deter- mining suitability of the water for these two uses is the degree of hardness of the water. While hardness is of significance in industrial processes, in this report it is not considered an inrportant criterion in judging the suitability of water for beneficieuL use, because of the relative ease with which it can be removed or decreased to acceptable limits. Quality of Ground ifater The quality of the ground water in the aquifers in the West Coast Basin was evaluated on the basis of past accumulations of data emd from over 250 special mineral analyses made in the course of this investigation. The evaluations and many of the mineral analyses of ground water from the various aquifers in the West Coast Basin are presented in the following paragraphs. The water wells for which mineral ajialyses are tabulated are shown on Plate 9. For method of location and well reference designations, see Appendix C. Mineral analyses of ground water extracted from the various aqui- fers in the West Coast Basin prior to 19^ indicate that in general such ground vater met the recommended limits for municipal and domestic uses and was Class 1 for irrigation purposes. In general, the character of this water was calciiom- sodium bicarbonate. Analyses of ground water considered representative of the water in the several aquifers prior to December 19^+0 are shown in Table 1. .TABLE 1 ANALYSES OF GROUND WATER FRCM REPRESENTATIVE WELIS IN WEST COAST BASIN PRIOR TO DECEMBER I9UO Aquifer State well niimber : Constituents in parts per million : Per- Date : : : : : : : : ;cent sampled ;Ca : Mg:Na+K: HCO:^: SO^: CI iNOq: TDS : Na Semi- perched 3S/13W-30D2 Gaspur i<-S/l3W-lifLl Gardena 3S/13W-20L3 Gage ifS/i3W-i6Ai Lynwood 3S/1UW-15G1 Silverado 3S/i4w-35Rl 1-13-33 58 18 5U 265 3-17-30 180 31 51 263 I92i<. 63 13 ^ 219 7-22-31 54 18 6k zjk 59 8- 7-lK) 56 17 56 262 7-23-31 35 12 52 2I+1 51 i^l 2 356* 1*8 96 261+ 753* 16 82 30 - 3^+1* 31 59 38 370* — 62 36 - 358* 37 3 27 Tr 2i+9* 1+5 * Total dissolved solids by summation. After 19^0^ it became increasingly evident that the mineral quality of the ground water in the upper aquifers (semiperched, Gaspur, Gage, and Gardena) was being impaired. The ground 'water from these aquifers is now extremely variable in character and mineral quality. The variation in quality is caused by numerous and complex waste discharges that have perco- lated and commingled \n.th ground water in the West Coast Basin during the past several decades. The pollution aspects of waste discharges have been -1+7- substantially reduced through the actions of the Los Angeles Regional Water Pollution Control Board euid local agencies. However, impairment of groiond water continues, primarily from migrating wastes discharged prior to the control of waste discharges. Impairment due to sea-water intrusion has also occurred and is a serious threat to the water quality in the Gaspur and underlying aquifers. Ground water from the underlying Lynwood and Silverado aquifers is generally of suitable quality for most uses, but is beginning to show the effects of impairment in a few areas. In the western i>ortion of the basin, adjacent to Santa Monica Bay, sea water has intruded the merged Silverado aquifer; the ground water quality has been impaired and the chlo- ride concentration approaches that of sea water. Semiperched Aquifer Mineral analyses of ground water from the semiperched aquifer indicate that the ground water generally does not meet the recommended criteria for municipal and domestic use, and is Class 2 or Class 3 for irrigation purposes. The character of this water is variable. The chlo- ride concentration generally exceeds 250 ppm in the vicinity of Gardena and 1,000 ppm along portions of Dominguez Channel. Analyses of ground water from selected wells in the semiperched aquifer are presented in Table 2. Gaspur Aquifer In general, the water in the Gaspur aquifer has deteriorated to the extent that the character and quality of the native water is obscure. Mineral analyses of ground water from this aquifer indicate that the ground -it8- TABLE 2 ANALYSES OF GROUND WATER FRCW SELECTED WELLS IN THE SEMIPERCHED AQUIFER : Date Constituents in parts per million : Per- State well : I z • : ; cent number : sampled : Ca : Mg :Na+K: HCO^: sou : CI NOo : TDS : Na 3S/13W-29F.1 1 I2-2I-U9 k- 4-57 75 138 18 42 70 126 309 282 94 185 46 198 74 458* 1,030 37 33 -30ML 5-19.U9 1-16-57 10-21-59 65 150 120 19 74 52 58 208 186 253 488 268 59 161 160 69 365 3^ 36 69 397* 1,432 1,280 3h 39 44 3S/lUW-2itQl 10-20-49 k- 3-57 11-10-59 175 164 200 56 59 7h 227 239 269 450 439 436 99 120 130 ^^53 440 585 85 59 64 1,320* 1,492 1,701 42 44 42 1+S/13W- 6K1 IO-24-U9 5- 7-57 10-21-58 67 118 114 15 28 26 75 115 105 186 250 247 86 279 273 101 116 96 4 7 441* 907* 797 41 38 35 * TotsuL dissolved solids by summation. vater generally does not meet the recommended criteria for municipal and domestic use, and is Class 2 or Class 3 for irrigation purposes. Several veils in the northern portion of Dominguez Gap produce ground vater with a chloride concentration of generally less than 5OO ppm. Elsewhere, the chloride concentration varies considerably, exceeding 1,000 ppm throughout a large portion of the aquifer. In the Terminal Island area, where source wells for oil field repressurization are in operation, the chloride concentration approximates that of the sea vater which has intruded this aquifer. The water contain- ing high chloride concentrations in the vicinity of Del Amo and Willow Streets is apparently the result of pollution from oil field brines and other industrieil waste discharges. The analyses of grotind water from selected wells in the Gaspur aquifer are presented in Table 3. -49- TABLE 3 ANALYSES OF GROUND WATER FR(M SELECTED WELLS IN THE GASPUR AQUIFER : Date Constituents in parts per million :Per- State well • • : • • : : : cent niimber : sampled : Ca : Mg : Na+K : HCO,: SOk : CI : NO- j: TDS : Na 1+S/13W-10G5 6-13-1^9 3-22-57 250 388 1+6 91 165 386 377 3I+8 50I+ 1,160 250 1+90 i,i+oi+* 31 2,760 38 -10J3 3-29-1+8 l+- 5-57 368 130 598 262 1+27 1,1^27 321+ 630 3,620 1+7 -11E2 6-13-1^9 3-20-57 80 160 12 28 86 1I+I+ 285 339 110 263 58 192 2 I489* 1+3 971+ 37 -11L2 8-15-51 3-20-57 10-15-59 3-21-61 123 131^ 188 23I+ 9 16 35 23 ll+O 172 265 227 31^3 293 220 320 161+ 226 609 521 160 210 269 262 2 1 3 861+ 1+7 955 ^+7 1,562 1+8 l,M+i+ 1+1 -26R3 9-17-59 392 178 -- 580 126 : i,120 - — — 5S/13W-3P11 3-11^-57 593 1,152 9,737 i+08 2,21+9 17,1^98 5 31^,291 76 * Total dissolved solids by summation. Gardena Aquifer Historically, groirnd water from the Gardena aquifer generally was acceptable for municipal smd domestic uses, and was Class 1 for irrigation purposes. Locally, pumping has ceased at msuiy fonner producing wells due to various reasons, including the deterioration of the mineral quality of the ground water. Ground water extracted from this aquifer by wells still in opera- tion usually has a chloride ion concentration of less than 200 ppm, and as a rule, its character is calcium-sodium bicarbonate. It is normally acceptable for municipal and domestic purposes and is Class 1 for irrigation -50- use. Analyses of groiind vater from selected wells in the Geo-dena aquifer are presented in Table k. TABLE k ANALYSES OF GROUND WATER FROM SELECTED WELLS IN THE GARDENA AQUIFER : Date Constituents in parts per million :Per- State well • • : : t : :cent number : sampled : Ca : Mg : Na+K : HCO3 : SO,, : Cl : NO,: TDS : Na 3S/13W-30J5 5-I8-U9 k- U-57 7h 139 17 35 67 9h 275 235 k9 85 188 13 U30* 920 36 28 3S/lUw-26Kl 5- 5-50 lO-lU-59 5-12-61 71 58 20 Ik 91 51 159 315 271 24 92 123 63 10 55U 530 kk 35 -33J3 7-18 -U9 3-12-57 J^l 1|2 10 11 57 50 198 2i^7 k9 36 38 292* 360 k6 ko -3'<-Dl 3-22-50 dk 23 71 250 65 128 h 500* 33 * Total dissolved solids by summation. Gage Aquifer Historically, ground water in the Gage aquifer for the most part was acceptable for municipal and domestic purposes and was Class 1 for irrigation use. Presently, the mineral quality of the ground water extracted from the Gage aquifer in a portion of the West Coast Basin is generally sodium bicarbonate to calcium-sodium bicarbonate in character and for the most part has a chloride concentration of less than 200 ppm. This ground water meets or slightly exceeds the maximum permissible concentration of mineral constituents for municipal smd domestic p\irposes and is Class 1 or Class 2 for irrigation uses. Mineral analyses of ground water from other portions of the Gage aquifer, especially in the coastal areas, indicate the water -51- is often sodium chloride-bicarbonate to sodium chloride in character. The chloride concentrations usually exceed 200 ppm. The ground vater in these portions of the aquifers is normally not acceptable for municipal and domestic purposes and is Class 2 or Class 3 for irrigation uses. Analyses of ground water from selected veils in the Gage aquifer are presented in Table 5. TABLE 5 ANALYSES OF GROUND WATER FROM SELECTED WELLS IN THE GAGE AQUIFER : Date Constituents in parts per mi llion : Per- State veil Z • • : : cent number : sampled : Ca : Mg : Na+K : HCOc^: SO/, : CI : NOc; : TDS : Na 3S/litW-i+Bl 11-26-U8 3-18-57 76 1U3 19 kk 3h 153 3U3 375 37 lli^ 102 250 92 500* 1,150 kk 37 -i8ai I+-30-50 3-12-57 U6 22 21 78 95 2ifU 2kk 8 26 117 120 3 50U ^^3 U8 US/13W-28N2 9-26-50 1-25-57 8- 3-59 3- 2-60 81 17^+ 116 29 60 50 246 28i^ 316 276 293 2i^5 115 15 k 160 398 752 768 k 992 l,i^31* 1,311* 59 Us/i3W-30Ai+ 1+-18-50 1-28-57 2k 30 9 8 63 67 232 189 3 k2 23 ^^3 2 2li0* 308 59 56 I * Toteil dissolved solids by summation. I Lynvood Aquifer Mineral analyses of ground water from the Lynvood aquifer indicate the ground water generally is acceptable for municipaJ. and domestic pur- poses and is Class 1 for irrigation uses. The character of the water extracted from this aquifer varies from sodium bicarbonate to calcium bicar- bonate, ajid the chloride concentration generally does not exceed 100 ppm. Mineral analyses of ground vater from selected veils are presented in Table 6 -52- TABLE 6 ANALYSES OF GROUND WATER FRCM SELECTED WELLS IN THE LYNWOOD AQUIFER : Date Constituents in peirts per million Per- State veil » • • • • • cent number : sampled : Ca : Mg : Na+K : HCOq: SO,, : CI : NOo : TDS : Na 3S/li+W-10Cl 7-26-i^9 2- 8-57 Uo 43 12 Ik kl 69 238 250 Tr 27 35 60 247* 448 37 45 -I'+Al 10-20-it8 2- 6-57 56 18 — 2kk 226 71 34 38 -- 30 -15B1 7-26-U9 2- 8-57 50 13 HQ 2hQ 262 28 35 40 .- 298* 37 i|S/l3W-28Nl 3-12-Uo 12-20-50 1-25-57 67 27 293 225 262 250 7 79 202 505 1 ,276 67 -3OKI 8-12-46 3-13-57 20 32 8 10 65 80 229 2^7 k 7 26 57 3 238* 300 63 57 * Total dissolved solids by summation. Silversuio Aquifer Mineral analyses of the ground water from the Silverado aquifer indicate that the ground water is generally acceptable for municipal and domestic purposes and is Class 1 for irrigation uses. The character of the water extracted from this aquifer varies from sodiiim bicarbonate to sodium- calcivim bicarbonate. The chloride concentration is generally not in excess of 100 ppm, except where impairment has occurred in the merged Silverado aquifer along Santa Monica Bay due to sea-water intrusion. Here the character of the ground water is sodium chloride. Mineral analyses of ground water from the Silverado aquifer are shown in Table 7« -53- TABLE 7 ANALYSES OF GROUND WATER FROM SELECTED WELLS IN THE SILVERADO AQUIFER : Date Constituents in parts per million Per- State well : I ! I cent niimber : sampled : Ca : Mg : Na+K : HCO3: SOU CI : NOq : TDS : Na 2S/14W-19K2 10-20-U8 3-18-57 11-10-58 3- 8-60 59 81 1+2 121 27 37 31+ 50 122 1I+7 167 172 351 332 370 1+1+2 61+ 89 91+ 135 128 215 121 261+ 1 576* 888 61+3* 961+* 51 1+6 -28 Fl 7-11-1+9 2- 5-57 72 77 31+ 28 93 81 I+3I+ 281 77 58 96 - 115 16 589* 517* 35 31+ -3*^01 k- 3-50 1^-12-57 50 11+ 11 58 59 220 21+1+ 56 20 28 3 33 319* 366 1+1 1+1+ 1^S/13W-15A11 6- l-k9 7-18-57 18 17 6 5 53 59 181 178 1+ 8 25 25 196* 2I+1 62 66 -21HU 5-12-50 IO-2U-56 26 10I+ 21+ 58 85 196 221+ 1 209 27 98 210* 681+ 66 32 -30A1 8-29-^9 1-28-57 25 2k 7 8 62 65 212 226 Tr 33 - 35 233* 320 59 57 I^S/lUW-lF2 5-12-50 3-20-57 10-20-60 h6 Ui 1+0 8 12 12 1+6 1+5 53 231 226 200 21 26 53 27 23 37 263* 290 318 1+0 36 39 -8D2 6-29-57 7 1,201+ 9,508 259 1,977 17,600 30,1+25 -- -36J1 11- 9-^ 1-22-57 29 31+ 6 13 126 181 3I+O 363 6 3 81 - 150 i+18* 668 71+ 71 *■ Total dissolved solids by svunmation. Quality of Imported Water To insure a continued supply of good quality water, surface water from the Colorado River, Mono and Owens Valleys, and ground water from the Central Basin are being imported into the West Coast Basin. -5I+- Imported softened Colorado River vater is sodivun sulfate in character. Its total dissolved solids generally exceeds 600 ppm. In con- trast, imported Mono-Owens water is calciiim bicarbonate in character. Its total dissolved solids generally is less than 250 ppm. The average analyses of treated and untreated Colorado River water for the year ending June 30, I960, and an analysis for Mono-Owens water are shown in Table 8. TABLE 8 ANALYSES OF IMPORTED WATER USED IN WEST COAST BASIN Water sampled Constituents in parts per million : Per- : : : : : : : : cent Ca : Mg : Na+K : HCO:^ : SOU : CI : NO^ : TDS : Na MWD untreated^ 80 26 86 136 263 7k 1.3 609° 38 MWD treated* ^1 15 ikj 13»^ 263 78 1.2 629° 61+ Mono -Owens'' 26 6 h^ 130 23 20 0.1 213° 52 a. Colorado River water data from 22nd Annual Report of The Metropolitan Water District of Southern California. b. Sample taken on April 19, I96O, Los Angeles Department of Water and Power . c. Total dissolved solids by summation. Impairment of Ground Water From the foregoing discussion it caji be concluded that although the natural ground water in the aquifers of the West Coast Basin was of excellent cpiality in the past, at present much of this resource has been impaired in quality. Such impairment has been brought about primarily by man's activities through overdraft eind improper waste disposal. Poorly constructed and sealed wells may serve as conduits for impaired water. -55- Sources of Ground Water Impairment Ground water in the West Coast Basin has been impaired by the intrusion of sea water in overdrawn aquifers, the improper disposal of industrial wastes including oil field brines, and possibly by the improper disix3sal of decomposable refuse. The lowering of ground water levels below sea level in most of the aquifers in the basin, caused by excessive ground water extractions from those aquifers, has caused a reversal in the slope of the pressure surface. The ground water pressure surface now slopes downward and inland from the ocean. Increasing quantities of sea water have entered the merged aquifers in the coastal fringe areas and as a result, extractions have entirely ceased or have been greatly reduced in these areas. By I960, ground water with a chloride ion concentration in excess of 500 ppm under- lay an area of about 8,000 acres along Santa Monica Bay, ajid in the vicin- ity of El Segundo, ground water of impaired quality underlay an area which extended inland from the coast about one and one-half miles. Similarly, in the San Pedro Bay area, sea water has intruded inland in the Gaspur aquifer about the same distance. Improper waste disposal has contributed to the impairment of ground water in some of the aquifers in the West Coast Basin. Altho\igh present waste disposal practices are controlled by the office of the County Engineer and the Los Angeles Regional Water Pollution Control BoaLrd, in the past, disposals of industrial wastes axid decomposable refuse were made with- out regard to the possible effect that such disposal would have on groiind water quality. During the period of most intense industrial growth, 1930 to 1950, large volumes of industrial wastes were discharged directly to the ground surface, and these wastes percolated and Intermingled with the ground -56. water of the upper aquifers. In the oil industry, large quantities of oil field brine wastes were percolated from separation ponds, thereby causing impairment to the quality of ground water in the underlying aquifers. Decomposable refuse deposited in many old dximps, now filled, covered, and laying idle for years, is at elevations subject to intermit- tent or continuous submergence by ground water. This refuse may be adversely affecting the quality of ground water, particularly in the semiperched aquifer. Protection Against Further Iii^)airment The intrusion of sea water is a direct result of overdraft caused by excessive extractions of ground water. The further impairment of ground water quality from this source can be prevented throiigh ground water manage- ment practices. The area of investigation is now part of the Central and West Basin Water Replenishment District which was formed primarily to provide additional water for recharging the ground water reservoirs of these two basins and to assist in reducing ground water extractions to a safe level. The accomplishment of these objectives will reduce the overdraft conditions and decrease the threat of further sea water intrusion. Also, as previously noted, the Los Angeles County Flood Control District is planning for the construction of additional facilities to create an underground pressure ridge by tne injection of fresh water into the underground basin that will halt the advancement of sea water into the aquifers of the basin. These measures should alleviate or entirely eliminate further impairment of ground water quality from this source. -57- The large quantities of ground water of excellent and, as yet, unimpaired quality which exist at present in the aquifers of the West Coast Basin must be protected from other sources of impairment if the full use of this valuable resource is to continue. The recent effort on the part of government, business, and industry to establish laws and regula- tions to control the discharge and disposal of wastes has been successful in minimizing the threat to ground water quality impainnent from existing waste discharges. However, large volumes of ground water impaired by past waste discharges remain in the basin, and could continue to mix with and impair the remainder of the ground water in the basin. Those aquifers which generally contain ground water of impaired quality are the semiperched, Gaspur, and portions of the Gage and Gardena. These aquifers overlie or are merged with Lynwood and Silverado aquifers which generally contain ground water of suitable quality except as previ- ously noted where sea-water intrusion has occurred. The Gardena aquifer is in direct hydraulic continuity with the adjacent Gage aquifer. The Lynwood and Silverado aquifers are generally separated from the overlying aquifers by relatively continuous sediments which restrict the downward movement of ground water with the exception of the area of mergence along Santa Monica Bay. Where these restricting horizons are absent, or exist as lenticular bodies, ground water of impaired quality from overlying aquifers may migrate downward and commingle with previously unimpaired water of acceptable quality in the underlying aquifers. Additionally, where the restricting horizons are present, and the aquifers are not naturally merged, improperly constructed or seeiled wells may become channels or avenues of interconnection. When this occurs, water of impaired quality, including some surface runoff Eind industrial -58- wastes, is conducted downward throiogh the well and the quality of water in each of the aquifers perforated by the well may be impaired. Thus, improperly constructed or sealed wells simultaneously play two incompatible roles: while extracting ground water for beneficial uses, they permit the Impairment of ground water quality in the aquifers from which the supply is being drawn. The well construction and sealing standards, presented in the next chapter, are designed to permit the wells In the West Coast Basin to continue in their beneficial role, but at the same time prohibit or alleviate the role played by such wells in the further impairment of ground water quality. -59- CIIAPTEJ? V. WATER WELL COIISTRUCTION AITO SEALING STAimARDS The standards for well construction and the standards for well destruction presented in this chapter are specifically developed for wells in the V/est Coast Basin. The objective of these standards is to protect the ground water in the basin from the impairment of quality which may occur when such wells are poorly constructed, or improperly destroyed, A discussion of the areas or zones for which these standards have been devel- oped is presented first, followed by a discussion on the standards for water well construction and sealing. Areas of Recommended Sealing Standards Geologic, hydrologic, and ground vrater qiiality characteristics within the West Coast Basin are so diverse and complex that it was nec- essary to develop specific standards applicable to the basin. Based on the ground water basin characteristics determined dtiring the course of this study, the West Coast Basin was separated into three areas or zones. Within each zone, a distinct set of specific standards for water well construction and destruction was developed and should be applied. These zones are shown on Plate 10, "Areas of liecommended Sealing Standards in V7est Coast Basin", as Zone 1, Santa Itonica Bay Coastal Area; Zone 2, Inland Area; Zone 3, Los Angeles River Area, Santa ilonica Bay Coastal Area - Zone 1 The Santa Monica Bay Coastal Area, Zone 1, is approximately two and one-half males wide, and extends south^^ard along the coastal area from the Ballona Escarpment to the Palos Verdes Hills, It also includes the -61- northern portion of the Palos Verdes Hills and the southern flank of the BaldvTin iJills, In this area the Bellf lower aqui elude is absent; therefore, water can percolate from the surface and commingle with ground water in the underlying aquifers. Inland Area - Zone 2 The Inland Area, Zone 1, embraces that portion of the West Coast Basin east of the Santa Ifonica Coastal Area, Zone 1, All aquifers described within this report are foimd in this area, with the exception of the Gaspur aquifer. Ihe Gage aquifer and the adjacent Gardena aquifer, are generally- considered to be the uppermost aquifers containing v/ater v/hich is generally acceptable for most municipal and domestic purposes and irrigation \ises. Consequently, standards for construction and sealing, \7hich will protect the Gage aquifer and/or the Gardena aquifer can be assumed to protect the underlying aquifers from water quality deterioration, Los Angeles Pdver Area - Zone 3 The Los Angeles River area. Zone 3, is an irregular north-south strip of land approximately one and one-half miles wide located in Dominguez Gap. The water-bearing units foiind in this area include the Gaspur, Gage, Lynwood, and Silverado aquifers. These aquifers are separated in a large portion of this area by varying thicknesses of relatively impermeable sedi- ments. In the remaining portion of the area the aquifers are merged. The areas of mergence between the Gaspur and Gage aquifers are shown on Elates 6 and 7. The Gaspur aquifer in the Vfest Coast Basin generally contains water of impaired mineral quality. Consequently, emy well construction -62- and sealing standards should protect the water of the Gaspur aquifer from further deterioration, and protect the underlying aquifers from downward movement of water from the Gaspur aqiiifer. General Water Well Construction Standards The follo\7ing general standards for both drilled and dvig wells are applicable to the entire West Coast Bsisin, but are supplemented by additional requirements in specific areas where geologic, hydrologic, or water quality conditions necessitate increased measures of protection. It shoiild be noted that local ordinances, or local health agencies may impose more stringent requirements than those presented in this report. These general standards are also applicable to water wells constructed by other methods. Specific water well construction standards are presented in a subsequent section. Location of Well Site The prospective vrell should be located at the highest point on the premises consistent with the general surroundings. It should be pro- tected from normal flooding, and from any surface or subsurface drainage capable of impairing the quality of the ground water supply. In addition, the well shovild be located up slope, with respect to the ground water gra- dient, from possible sources of contamination. The well should not be located within certain minimum distances of potential soiirces of contamination. These minim\:im distances as adopted from recommendations by the California Department of Public Health, Bureau of Sanitary Jiiiigineering, are: .63- Sewer, \ra,tertight septic tank or pit privy 50 feet Se\ra.ge disposaJ. field (subsurface), barnyards, or fenced areas for livestock 100 feet Cesspools or seepage pits I50 feet In special cases, the local health officer may approve the location of a well within lesser distances if proof can he shown that threat to public health or impairment of ground ■vrater vrill not occ\ar. Conversely, special characteristics of certain areas may require that the local health officer increase these minimum distances to prevent possible contamination of the water in the •srell. The well should be located so that it is reasonably accessible, with adequate clearances provided for the proper equipment for cleaning, treatment, repair, test, and other maintenance which may be necessary. When a well is constinicted adjacent to a building, it should be located so that a vertical extension of the centerline of the well will clear any projection fronv the bioilding by a minimum of two feet. Casing To obtain and maintain the optimum quality of ground water, and to gain the maximum operational life of the well, the proper casing should be installed. The casing should be designed to withstand the forces which may act upon it during and after installation. It should also be resistant to the electrolytic and corrosive effects of earth and water. There is a variety of material used for casing. Steel is the material most commonly used for drilled, driven, and Jetted wells, and concrete or brick for dug wells. There is also limited use of other mate- rial such as galvanized metal, plastic, clay, and asbestos -cement. -64- Suggestions as to the mlnlnitun thickness of steel casings are contained In Appendix D together with a list of applicable specifications of the American Society for Testing Materials and the American Water Works Association, General specifications for concrete casing for dug wells are also presented in Appendix D, Steel well casing and conductor pipe should not be considered to have an imlimited useful life. It should be inspected from time to time to ensure that it has not deteriorated imder conditions of use. Casing Dieuneter Reduction. Whenever the casing diameter is reduced, the two casings should overlap by at least eight feet and the nrnniifl-r space thus produced should be adequately sealed to make the joint watertight. This seeiling can be accomplished by the proper placement of impervioias cement grout or a packer. Joints . Watertight casing should be used to prevent the entrance of \mdesirable water and loose material into the well. Steel casing should be made waterti^t by a method such as butt welding, collar welding, or threaded collars. In a dug well where concrete casing is employed, a sxifficient amount of impervious mortar should be used to insure that all sections are securely joined. Perforations . The perforation of steel casing should not undiily weaken, tear, or deform the casing, and the casing should not be perforated within 50 feet of the ground surface. In dug wells, only standard sections of perforated concrete casing should be used. In drilled wells, perforating more than one aquifer in any well should be discouraged, even xmder ideal .65- water qviality conditions. MixLtiple aquifer perforations shovild be made only If all perforated aquifers contain water of similar quality. Sealing Inteinmls of Strata Penetrated by Wells Aquifer or strata (intervals) penetrated during the drilling process which might contribute water of impaired quality -co the well should be sealed. All sealing should be permanent, and should completely restrain the movement of undesired water into the well. Standard sealing methods and materials should be employed. In developing, redeveloping, or conditioning a well, care should be taken to preserve the natural bar- riers to groimd water movement between aquifers. Two methods commonly used in seauLing undesirable intervals of strata are by pressure grouting and insertion of a liner. These two methods are shown on Figure 4, and are discussed at this point; other suitable methods are discussed later under "Surface Protection of Wells", Pressure Grouting Method . In this method impervious grout such as Portland cement is punrped down the grouting pipe into the well and then forced through existing perforations or new perforations in the casing into the annulax space ajid formation surrounding the well. The interval of undesirable strata is isolated in the well by a packer or a plug set at the bottom and a packer set at the top of the intei^ral to be sealed. The pressxire that forces the grout into the annular space to be sealed must be maintained until the grout has set, af^er vrtiich, the material remaining in the well is removed by drilling. Liner Method . In this method a metal liner is placed inside the original casing so that it extends at least 10 feet above and below -66- FIGURE 4 GROUT INDUCED INTO - GROUTING PIPE UNDER PRESSURE AQUICLUDE WELL CASING- GROUT RETAINER- AQUIC LUD E FIG. 4 la) PRESSURE GROUTING METHOD (I FIG. 4{b) LIN (CEMENTED AQUICLUDE p .■ V 4- \ ■- A . A /ft ..D I » o AQUIFER e> o o " o o Ar e> o o 01 LlJ 2 MALLEABLE END OF LINER "~ — DRILLED HOLE- AQUICLUDE / o o ER METHOD IN PLACE) FIG.4 (b) LINER METHOD {SWAGED IN PLACE) NOT TO SCALE TYPICAL METHODS FOR SEALING INTE RVA LS OF STRATA the perforated interval to be sealed, A grout retaining seal is placed at the "base of the annular space between the liner and the well casing. A grouting pipe is extended to the bottom of the interval to be sealed, llie annular space between the liner and well casing is then filled with grout. Where corrosion is not a problem, a liner with malleable metal sections at both ends may be swaged tightly against the casing to form a watertight seal. Siirface Protection of V/ells The following standards should be employed to insure that sur- face water and/or shallow ground water will not enter the well. These surface protection features, shown on Figure 5^ inclvide the requirements for the sanitary seal that extends from the ground surface to the ^n^^n^^Tn^m depth required by the well location, and the req\iirements for the well components located at the surface. Drilled Wells . The annular space between the drilled hole and either the well casing or the conductor pipe should be sealed with Im- pervious grout such as port land cement or other types of sealing material approved by the inspecting agency. The purpose of this seal is to preclude from the well the downward percolation of surface runoff or the entrance of undesirable shallow ground water. This annular space seal should extend at least 50 feet down from the ground sirrface and have a minimum thickness of two inches. For wells 50 feet or less in depth, the annular space shoTild be sealed at least three-fourths of the depth of the well from the groxind sia-face downward. Two procedures which are utilized to construct a surface seal in the annular space are given below. -68- FIGURE m^M ^7^ > GRAVEL FILL PIPE -M^ el t, I •I f I WATER TIGHT SEAL BETWEEN " CASING AND CONDUCTOR PIPE CONCRETE PEDESTAL MEASURING PIPE ^GROUND ^ /^SURFACE^ ' dm/// 7^^ n GRAVEL ENVELOPE GROUT SEAL CONDUCTOR PIPE CASING DRILLED HOLE- DRILLED HOLE -PERFORATIONS ■ P'- mw^ FIG. 5 (a) WELL WITH GRAVEL PACK FIG. 5(b) WELL WITHOUT GRAVEL PACK NOT TO SCALE TYPICAL SURFACE PROTECTION FEATU RES Grouting Pipe Method, In the grouting pipe method a grout sesLL is placed in the annular space from the bottom up through a grout pipe suspended in the annular space. If the annvilar space is restricted, it may be necessary to jet the grout pipe to the required depth. The grout- ing pipe shovild remain submerged in the grout during the placement of the seal. It may be necessary in this method to provide a grout retaining seal at the bottom of the annular space. Pressure Cap Method, In the pressiore cap method, the conductor pipe is suspended about two feet above the bottom of the drilled hole, filled with fluid, and capped with a pressure cap, A grout pipe is extended through the pressure cap and the conductor pipe to the bottom of the hole, and impervious grout is forced through the grout pipe, up the annular space between the conductor pipe and the drilled hole, to the groimd surface, Gravel-Packed Wells , In gravel-packed wells the top of the gravel envelope should generally be terminated at least 50 feet below the surface of the ground, although terminations of the envelope at greater depths axe required in certain portions of the West Coast Basin, as discussed later under "Specific Water We3J. Construction Standards", The anniolar space from the top of the gravel envelope to the surface of the ground should be com- pletely filled and sealed with impervioiis grout, such as portland cement. If a conductor pipe is used, the gravel envelope may be termi- nated at the surface of the ground, providing the annulax space between the drilled hole and the conductor pipe is sealed with impervious cement grout to the req\iired depth, A watertight cover should be installed between the conductor pipe and the well casing at the ground svirface, as -70- shovm on Figure ^. A gravel fill pipe may be installed through the seal if desired, but the fill pipe shovild be made watertight at the ground surface . Dug Wells . The ann\ilar space between the dug hole and the well casing should be sealed to a minimiom depth of 50 feet, or three-fourths of the well depth if it is less than 50 feet deep, in a manner similar to that discussed for drilled wells . Dug wells should also be protected by a surface cover. This cover should be made of reinforced, watertight con- crete, at least fo\ir inches thick at its outer edge. The upper s\arface of the cover should be sloped away from the colijmn pipe or puiiip colximn in all directions, and extended beyond the outer edge of the curbing. The cover should be sealed watertight to the curbing with a nibber gasket, mortar, mastic, or other suitable material. All openings in the cover should be protected to prevent entrance of water or foreign material into the well. A sounding tube in a dug well should be extended through the cover into the well. This tube should be equipped with a watertight screw cap. Well Pits . The use of well pits should be avoided whenever possible. Well pits should not be constructed to a depth below the recorded high water table. If a well pit is necessary, the walls and floor should be constructed of watertight reinforced concrete. The top of the pit should be covered with a structurally sound, watertight con- crete slab or with a house of satisfactory construction. The floor of the pit should be sloped away from the well casing. A gravity drain or automatic sunip pump should be installed so that any water accumulating in the pit will be discharged a minimum distance of 30 feet from the pit. -71- The well casing should extend at least l8 inches above the floor of the pit. Pedestal and Pump . In "both drilled and dug wells, the top of the casing should extend a minimum of l8 inches above the ground surface and at least one inch above the top of the elevated portion of the pedestal. Upon completion of a well, and until the installation of the pump, a waterti^t cap or plate should be placed on the top of the casing. This plate should be fastened securely and rigidly enough to support normal external loads, A monolithiceLlly poured concrete pedestal should be constructed in a meumer simllsir to that as shown on Figure 5 on thoroughly compacted earth around the top of a well, irrespective of whether the p\amp is mounted over the well, is offset from the casing, or is of the submers- ible type. At its extreme outer edge, the pedestal should rise to at least six inches above the stirrounding ground surface. The pedestal should slope away from the casing in all directions. When a punrp is set on top of the casing, a seal should be provided to make a watertight joint between the pvimp and casing. The seal should be shaped in a manner that will prevent collection and re- tension of surface water or other matter. If the pump is offset, a packer or seal should be provided to make a watertight seal between the pipe column or other pipes, and the casing or cover in drilled or dug wells. The top of the seal should be so shaped to prevent the col- lection and retention of surface water or other foreign material. -72- The punip shoiild be designed and maintained in a manner that will prevent lubricating oil from dripping or discharging into the well. If a pump house is used, it sho\ild be equipped with a concrete floor sloped away from the well to prevent retention and inflow of surface water and foreign materials. A drain shoiild be provided which discharges out- side the pump house. If there is no natural slope from the pump house, the drain should discharge at least 30 feet from the well. Adequate ventilation sho\ild be provided. Sounding Tube and Air Vent Pipe . In drilled and diog wells, a sounding tube or access pipe at least two inches in diameter shoxild be installed through the surface seal or surface cover into the casing. One end of the tube shoiild be welded flush with the inside of the casing. The other end of the tube should be equipped with a watertight screw cap. If an air relief vent pipe is provided, it should be terminated in a downward direction at least l8 inches above the ground surface. The end of this vent pipe should be screened. Water Quality Sampling In order to determine the quality of ground water which will be available, all wells should be sampled for bacteriological and mineral quality immediately following construction. It may also be advisable to take samples of the water during construction. All wells used to supply water for domestic purposes should be sampled and tested in accordance with, and should comply with, the United States Public Health Service Drinking Water Standards, as well as with any other standards established by state, local, or other agencies. -73- Disinfection Prior to use for drinking water pvirposes, the well should be disinfected with a chlorine ccmpovind. Sufficient disinfectant should be added to the standing water in the well to give a residua], of 50 PPm free chlorine. After the disinfectant has been placed in the well, the punqp should be started and stopped several times to thorovighly mix the disin- fectant with the water in the well. The pvmip should then be stopped emd not operated for a period of 2k ho\irs. After 2k hours, the pumping should be resumed until the well is free of chlorine. The water should then be tested to see that it is free of collform bacteria. This procediire should be repeated vintll the water meets the bacteriological standards prescribed by the California Depajt-tment of Public Health. The quantities of some standard chlorine coii^)o\uids required to provide 50 ppm of free chlorine for each 100 feet of water-filled casing are presented in Table 9* TABLE 9 AMOUNT OF CHLORINE CCSMPOUNDS REQUIRED TO PROVIDE 50 PPM FREE CHLORINE FOR EACH 100 FEET OF WATER-FILLED CASING Diameter of casing in Inches (7056) HTH, Perchloron, etc, (Dry weight) (25^) Chloride : (5^) Purex, of line : Chlorox, etc. (Dry weight) ; (Liquid measure) 2 l/k ounce 1/2 ovmce 2 ovmces k 1 oxmce 2 ounces 9 ounces 6 2 ounces k ounces 20 ounces 8 3 ounces 7 ovmces 2-1/8 pints 10 k ounces 11 ounces 3-1/2 pints 12 6 o\mces 1 pound 5 pints 16 10 ounces ^-3/k pounds 1 gallon 20 1 pound 3 pounds 1-2/3 gallons 2k 1-1/2 pounds k pounds 2-1/3 gallons Note: It is s\iggested that where wells to be treated are of unknown depth or volume, at least one pound of 705^ available chlorine or two gallons of household bleach such as Clorox or Purex (55^ chlorine) should be added in lieu of the use of the above table. -71*- Specific Water Well Construction Standards All construction standards previoiosly described imder "General Water Well Construction Standards" should universally apply and in addition, the following specific construction standards for the individual zones vrLthin the West Coast Basin should apply. Santa Monica Bay Coastal Area - Zone 1 To minimize any further -deterioration of ground water, all future water wells constructed in Zone 1 shoxild employ a surface seal to prevent the entrance of surface water into underlying aquifers through the well opening. The complete fulfillment of all req-uirements listed under general construction standards should he considered as the minimum specific water well construction standards in Zone 1, Inland Area - Zone 2 In addition to meeting all requirements set forth under general construction standards, all futvire water wells constructed in Zone 2 should employ an effective seal in the annular space from the top of the Gage aquifer or the Gardena aquifer to the gro\md surface. The approximate contours on the top of the Gage aquifer and the Gardena aquifer are sho-( 6, and 8 is required to determine the applicable case. These plates show contours on top of the Gaspur aquifer, Gage aquifer, and the Lower Sealing Horizon in Dominguez Gap, respectively. All future water wells constructed in Zone 3 should conform to the specific reccaaraendations set forth under any one or a combination of cases described in the following paragraphs. Case I - Wells Producing from the Gaspur Aquifer or from the Merged Gaspur and Gage Aquifers . All future water wells constructed to produce from these aquifers should comply irith the general construction standards. In addition, an impervious seal should be placed in the annular space extending from the top of the Gaspur aquifer or the merged Gaspur and Gage aquifers to the ground surface. The approximate contours on the top of the Gaspur aquifer and the merged Gaspur and Gage aquifers are shown on Plate 5. If a well is perforated in the merged Gaspur and Gage aquifers it shotild not be perforated in any underlying aquifer. Case II - Wells Producing from the Gage Aquifer . All future water wells constructed to produce from the Gage aquifer should comply with the general construction standards. In addition, an itnpervious seal should be placed in the annular space from the top of the Gage aquifer to the grovmd surface. The approximate contours on the top of this aquifer are shown on Plate 6. Case III - Wells Producing from Lynwood and Silverado Aquifers . All future water wells constructed to produce from the Lynwood and Silverado aquifers should comply with the general construction standards. In addition. -76- cm impervious seal should be placed in the annular space from the ground surface to 10 feet below the top of the "lower sealing horizon." The approximate contours on the top of this horizon are shown on Plate 8. Wells perforated in the lower Pleistocene aquifers shovild not be per- forated in the overlying Gage, Gaspur, or semiperched aquifers. General Sealing Standards for Water Well Destioiction As discussed in Chapter IV, wells may provide a pathway for the transmission of groiind water from one aquifer to another in the West Coast Basin. When a well no longer serves a useful purpose, or has fallen into such a state of disuse and disrepair that it may become a soiirce of impairment to grovtnd water quality, it should be properly sealed and destroyed in order to prevent such impairment. As used in this section, sealing refers to plugging or filling a well with impervious material such as Portland cement grout. A properly destroyed well that has been adequately sealed is illustrated in Figure 6. Prior to destroying any well, either the Los Angeles Coimty Flood Control District, the United States Geologic Survey, Groxmd Water Branch, or the California Department of Water Resources should be con- tacted. In this manner, these agencies would be afforded the opportunity of considering the well for possible monitoring of grovind water conditions. The following general procedures for sealing wells which are to be destroyed shoixLd be utilized in all zones of the West Coast Basin, but should be supplemented by specific sealing standards where required. The specific sealing standards applicable to water well destruction are presented in the next section. ■77- FIGURE 6 ^ / GROUND SURFACE- NATIVE SOIL ' A.- .5 "id . T zj^ _EXCAVATED_ HOLE 1 7^^ NATIVE SOIL — 5 CONDUCTOR PIPE CASING EXISTING GRAVEL — ENVELOPE EXISTING GROUT SEAL- DRILLED HOLE f i 'J . - ' \'s GROUT FOR WELL " DESTRUCTION ' -DRILLED HOLE- - :f-A — - I J£H ■OLD OR NEW PERFORATIONS DEPTH TO WHICH SPECIFIC SEALING IS REQUIRED FOR" EACH ZONE FILLER MATERIAL EXISTING PERFORATIONS- FIG. 6 (a) WELL WITH GRAVEL PACK FIG. 6(b) WELL WITHOUT GRAVEL PACK NOT TO SCALE TYPICAL SEALING FEATURES OF DESTROYED WELLS (1) When a well is to be destroyed, the interior of the casing should first be cleaned out to eliminate any obstructions which might interfere with effective sealing procedures. After cleaning, the entire reach to be sealed, from groxind surface to the minimum depth required in each zone, should be free of all extraneous materials and obstructions. (2) The open well should then be filled with impervious filler material from the bottom of the well up to 5O feet below the ground surface or to the minimiom depth required for each zone. The filler material may be portland cement grout, impervious native soil, clay, or other suitable impervious material. (3) If there is an annular space or if its occurrence between the drilled hole and the well casing is unknown, the casing should be ripped or perforated upward, commencing just above the top of this impervious filler material for a distance of approxi- mately five feet. A grouting pipe should be placed inside the well casing and a packer should be installed above the rips or perforations. Portland cement grout shoiold be applied through the rips or perforations by a pressure grouting method until a grout plug fonns in the annular space. After the grout has set, the well casing shovild be perforated at a higher point and the pressure grouting operation repeated until grout re- turns to the groiind surface through the annular space between the drilled hole and the well casing. If the annular sealing operation is not successful, that is, if the grout does not -79- return to the ground surface, the casing should be ripped or perforated from the top of the irpper packer to the ground surface. The annular space and casing should then be filled with Portland cement grout by a pressure grouting method. This procedure should apply also to the gmnular space between a conductor pipe and vrell casing. If an annular space exists between the drilled hole and the conductor pipe it sho\ild also be sealed. If the annular space is restricted, the grouting pipe may be jetted in place, (U) If a well does not have an annvilar space between the drilled hole and the casing, the casing should be filled with port land , cement grout from the top of the filler material to the top of the casing using a dump bailer, grouting pipe, or similar means. The sealing material should be applied continuously, beg inning at the top of the filler material and moving upward to the top of the well casing, (5) If the annular space of a well has previovisly been sealed with a sealing material such as portland cement grout dvtring well construction, the seal need not be disturbed. However, if possible, the seal shoiild be inspected to ensxire that it con- forms with the standards presented in this report. The annular seal should be extended and the well filled with portland cement grout to the depth required for each zone. (6) Where the maximum depth of a well being destroyed is less than 50 feet, the sealing standards apply to its maximum depth. -80- (7) For the protection of the seal and to facilitate the future use of the well site, a hole at least one foot larger in diameter than the original drilled hole should he excavated around the outside of the well casing to a depth of six feet below the ground surface. The well casing should then be cut off six inches above the bottom of this excavation and removed. During the sealing operation, the portland cement grout \xsed to fill the well should be allowed to spill over into the excavation and fill, it for a thickness of one foot and form a cap which has a diameter of at least one foot greater than the diameter of the original drilled hole. This procedure should result in the exposed edge of the casing being covered with six inches of grout. After the sealing material has set, the excavation should be filled with native soil as shown on Figure 6, Specific Sealing Standards for V/ater Well Destruction All sealing standards previously described under "General Sealing Standards for Water Well Destruction" should universally apply, and in addition the following specific sealing standards for the individual zones within the West Coast Basin should apply, Santa Monica Bay, Coastal Area - Zone 1 The complete accomplishment of the general sealing standards previoxisly described to a minimimi depth of at least 50 feet below the ground surface should be considered the minimutn sealing standards for water weULs in Zone 1. .81- Inland Area - Zone 2 The complete accomplishment of the general sealing standards previously described, from the top of the Gage aquifer or the Gardena aquifer to the ground surface, sho\ild be considered the minimum sealing standards for water wells in Zone 2, The approximate contours on the top of the Gage aquifer and the Gardena aquifer sure shown on Plate 7, Los Angeles River Area - Zone 3 The complete accomplishment of the general sealing standards previously described, to the depths specified for the following three cases, should be considered the minimum sealing standards for water wells in Zone 3» (l^e reasons for these cases were described under the section on "Specific Water Well Construction Standards",) Case I - Wells Producing from the Gaspur Aquifer or from the Merged Gaspur and Gage Aquifer , The sealing of any water well producing from these aquifers should be from the top of the Gaspur aquifer or the top of the merged Gaspur and Gage aquifers to the ground surface. The approximate contours on the top of the Gaspur aquifer and the merged Gaspior and Gage aquifers are shown on Plate 5» Case II - Wells Producing from the Gage Aquifer . The sealing of any water well producing from the Gage aquifer should be from the top of the Gage aquifer to the ground surface. The approximate contours on the top of this aquifer are shown on Plate 6, -82- Case III - Wells Producing from Lynvood and Silverado Aquifers . The sealing of any water wells producing from the Lynwood and Silverado aquifers should he from 10 feet helow the top of the "lower sealing horizon" to the ground surface. The approximate contours on the top of this horizon are shown on Plate 8» -83- CHAPTER VI, SUMMARY OF FINDINGS AND CONCLUSIONS, AND RECOMMENDATIONS The findings and conclusions presented in this chapter are .derived from the results of the investigation which have been presented in the previous chapters. The recommendations are based upon these findings and conclusions and emphasize the need for adopting well con- struction and sealing standards in the West Coast Basin. Findings and Conclusions 1. Ground water ^ extracted from underlying aquifers ^ is an important part of the water supply of the West Coast Basin. 2. Aquifers which occur in the West Coast Basin are generally sep- arated and contain groimd waters of varying quality. They are the semiperched, Gaspur^ Gardena^ Gage^ Lynwood, and Silverado aquifers . 3. Generally^ groiind water in the various aquifers does not commingle; exceptions to this occur where the aquifers are naturally merged, as along Santa Monica Bay, or where faulty well construction or destruction permits an artificial interchange of ground water. ^4-. The quality of the native ground water in the shallower aquifers, such as the semiperched aquifer, has been impaired or polluted by man's activities to the extent that much of the water is presently unfit for most beneficial uses. 5. The quality of the groiuid water in the deep aquifers, the Lynwood and Silverado, is generally acceptable for most municipal and domestic pvirposes and irrigation uses, except in certain -85- etreas where its quality has been adversely eiffected by the intmasion of sea water. 6. Wells which axe improperly constructed or improperly destroyed may act as conduits, transmitting impaired water from the ground surface or from the shallower aquifers to the deeper aquifers . 7. The West Coast Basin can be divided into three major zones on the basis of geology and hydrology. General well construction and sealing standards to be universally applied in all areas of the basin, and \mique requirements for specific constmc- tion and sealing standards to be applied in each of the major zones have been developed during this investigation to prevent the artificial interchange of ground water between aquifers. 8. Adoption of, and compliance with, the water we21 construction and sealing standards set forth in this report will prevent the impairment to ground water quality caused by substandard wells. Recnrnmendations It is recommended that the Los Angeles Regional Water Pollution Control Board, local agencies, local water producers, and water well drillers accept these standards, and apply them in a manner that will assist them in preserving and improving the quality of the common groiind water supply. -86- PLATE I LEGEND HUHTINOTONN BEACH WEST COAST BASIN BOUNDARY OF GROUNDWATER BASIN BOUNDARY BETWEEN PHYSIOGRAPHIC FEATURES (DOTTED WHERE APPROXIMATE OR POORLY DEFINED) BOUNDARY OF FOREBAY AREA NOTE BOUNDARY BETWEEN FOREBAY AND PRESSURE AREA FROM BULLETIN 45 (CALIF. D.W.R. 1934) STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY LOCATION AND PHYSIOGRAPHIC FEATURES IN WEST COAST BASIN SCALE OF MILES 2 PLATE I LEGEND ■^^~ WEST COAST BASIN ^^^— BOUNDARY OF GROUNDWATER BASIN BOUNDARY BETWEEN PHYSIOGRAPHIC FEATURES (DOTTED WHERE APPROXIMATE OR POORLY DEFINED! .._ __ BOUNDARY OF FOREBAY AREA NOTE BOUNDARY BETWEEN FOREBAY AND PRESSURE AREA FROM BULLETIN 45 (CALIF. DWR 1934) STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY LOCATION AND PHYSIOGRAPHIC FEATURES IN WEST COAST BASIN SCALE OF MILES PL Alt i. LEGEND k 7 OqI Qsr q: Qso UJ Q- < n z> Qlw r o -1 Osp L ^ ill III III SEDIMENTARY ROCKS ALLUVIUM GRAVEL, SAND, SILT, AND CLAY, ACTIVE DUNE SAND WHITE OR GREYISH, WELL SORTED SAND. OLDER DUNE SAN D FINE TO MEDIUM SANDWITH SILT AND GRAVEL LENSES. LAKEWOOD FORMATION (INCLUDES TERRACE DEPOSITS, "PALOS VERDES SAND," AND "UNNAMED UPPER PLEISTOCENE DEPOSITS") MARINE AND CONTINENTAL GRAVEL, SAND, SANDY SILT, SILT,ANDCLAY WITH SHALE PEBBLES. SAN PEDRO FORMATION MARINE AND CONTINENTAL GRAVEL, SAND, SANDY SILT, SILT, AND CLAY, PICO FORMATION MARINE SAND, SILT, AND CLAY INTERBEDDED WITH GRAVEL. REPETTO FORMATION MARINE SILTSTONE WITH LAYERS OF SANDSTONE AND CONGLOMERATE MONTEREY FORMATION ■~ MUDSTONE, DIATOMITE, AND SHALE. IGNEOUS AND METAMORPHIC ROCKS VOLCANIC ROCKS CATALINA SCHIST FAULT(DASHED WHERE APPROXIMATELY LOCATED) CONCEALED FAU LT 4 ANTICLINE (DASHED WHERE APPROXIMATELY LOCATED) — I SYNCLINE (DASHED WHERE APPROXIMATELY LOCATED) CONTACT (DASHED WHERE APPROXIMATELY LOCATED) j \ LANDSLIDE AREA WATER WELL "1 WELL LOGS USED IN PREPARATION OIL WELL J 0"^ GEOLOGIC SECTIONS -a' line LOCACATION of GEOLOGIC section presented on plate 3 • A5 4-1-6 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUNDWATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAL GEOLOGY IN W EST COAST BASIN SCALE OF MILES 1/2 2 LEGEND Si / °^ ii^ Oal Qsr o: Oso UJ ^1 Z3 Qlw I- LU J s o Qsp iiiil SEDIMENTARY ROCKS ALLUVIUM GRAVEL, SAND, SILT, AND CLAY ACTIVE DUNE SAND WHITE OR GREYISH, WELL SORTED SAND. OLDER DUNE SAN D FINE TO MEDIUM SANDWITHSILT AND GRAVEL LENSES. LAKEWOOD FORMATION (INCLUDES TERRACE DEPOSITS, "PALOS VERDES SAND," AND "UNNAMED UPPER PLEISTOCENE DEPOSITS") MARINE AND CONTINENTAL GRAVEL, SAND, SANDY SILT, SILT,ANDCLAY WITH SHALE PEBBLES. SAN PEDRO FORMATION MARINE AND CONTINENTAL GRAVEL, SAND, SANDY SILT, SILT, AND CLAY. PICO FORMATION MARINE SAND, SILT, AND CLAY INTERBEDDED WITH GRAVEL REPETTO FORMATION MARINE SILTSTONE WITH LAYERS OF SANDSTONE AND CONGLOMERATE MONTEREY FORMATION ~- MUDSTONE, DIATOMITE, AND SHALE. IGNEOUS AND METAMORPHIC ROCKS VOLCANIC ROCKS CATALINA SCHIST FAULTCDASHED WHERE APPROXIMATELY LOCATED) >••• CONCEALED FAULT D -4 ANTICLINE (DASHED WHERE APPROXIMATELY LOCATED) — I SYNCLINE (DASHED WHERE APPROXIMATELY LOCATED) CONTACT(DASHED WHERE APPROXIMATELY LOCATED) j if LANDSLIDE ARE A • A5 WATER WELlI WELL LOGS USED IN PREPARATION 4-1-6 OIL WELL J OF GEOLOGIC SECTIONS -a' LINE LOCACATION OF GEOLOGIC SECTION PRESENTED ON PLATE 3 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUNDWATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAL GEOLOGY IN W EST COAST BASIN SCALE OF MILES 1/2 2 LEGEND SEDIMENTARY ROCKS I _ , — I ftLLUWIUM I Qui I GfiflVEL.SAND, SILT, AND CLAT r-T^— rri active oune sano L Wat ill WHITE OB GREYISH, WELL SORTED SAND [..ft,.. J OLDER OUNE S4N0 L : :S*! GAGE AND GAHDENA AQUlF t ^.f-r:*'l FORMATION ERS IN THE LAKEWOOD LYNWOOD AND SILVERADO AQUIFERS IN THE SAN PEDRO FORMATION WATER WELL ■ LOCATIONS Of GEOLOGIC SECTIONS ARE SHOWN ON PLATE g STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY generalized geologic sections a-a', b-b', and C-C' in west coast basin HORIZONTAL SCALE OF FEET 20O0 2000 4000 6000 NOR TH SOUTH . 2 a 1 . u a - - s i - T . 1 7 v:-:'-:--:- ^5Tr?J?:v-j7TnT7^ ^ ■ ■ „--.'!;;:l. ....1 .LLUV(U« --• ...,r^^ ,_ TS ~. _^-sssss SOT, » S5E=Eirrr-;'-';--'^" Wm^mm.^ , \a::5liwsi^fc...^:.; - , - ■ , r " __--—' - '- "f''l|fe>. ''^ ,/■""■ '^^^^■y^^ - '- \ ■■-•, . >"' '^-■'.-i - 1 \ \ .- ' i - " ':■■■■:■.■- .j;.^^- / WILMINGTON NTICLIHE - \ yP^"" / ^^' ,^- ' — "' — -__ - \ =..„.. / , ^^^ PICO FOSMBTION " """'" >'-^ ■ [ZZl "■"«'"" DEPARTMENT OF WATER RESOURCES RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY generalized geologic sections a-a', b-b', and C-C* in west coast basin SECTION B-B PLATE 4 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAL EXTENT OF THE GAGE, GARDENA, AND GASPUR AQUIFERS IN WEST COAST BASIN SCALE OF MILES I PLATE 4 *" STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAL EXTENT OF THE GAGE, GARDENA, AND GASPUR AQUIFERS IN WEST COAST BASIN SCALE OF MILES I isez LEGEND BASIN BOUNDARY AfiEA UNDERLAIN BY THE GAGE AQUIFER AREA UNDERLAIN BY THE GAROENA AQUIFER I AREA OF HYDRAULIC CONTINUITY BETWEEN THE GAGE AQUIFER I AND THE OVERLYING GASPUR AQUIFER STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAL EXTENT OF THE GAGE, GARDENA, AND GASPUR AQUIFERS IN WEST COAST BASIN PLATE 5 ,3S. 4S. ST 18 ST 30 ^ 31 or a: •-60- LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE GASPUR AQUIFER AREA OF HYDRAULIC CONTINUITY BETWEEN THE GASPUR AQUIFER AND THE UNDER- LYING GAGE AQUIFER note; contours are referenced to mean sea level u s g s, datum STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY Pe DPO 0A^ CONTOURS ON THE TOP OF THE GASPUR AQUIFER IN DOMINGUEZ GAP, WEST COAST BASIN SCALE 1/2 OF PLATE 5 V nn ST. 18 ST 30 31 tr cr •-60- LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE GASPUR AQUIFER AREA OF HYDRAULIC CONTINUITY BETWEEN THE GASPUR AQUIFER AND THE UNDER- LYING GAGE AQUIFER note; CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U SG.S, DATUM STATE or CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTMCRN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY P^ DPO 0A^ CONTOURS ON THE TOP OF THE GASPUR AQUIFER IN DOMINGUEZ GAP, WEST COAST BASIN SCALE 1/2 OF PLATE 6 18 30 31 (T CC -140- LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE GAGE AQUIFER AREA OF HYDRAULIC CONTINUITY BETWEEN THE GAGE AQUIFER AND THE OVERLYING GASPUR AQUIFER note; CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U S G S- DATUM STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHCRN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY f^ DP^ 0A^ CONTOURS ON THE TOP OF THE GAGE AQUIFER IN DOMINGUEZ GAP, WEST COAST BASIN SCALE 1/2 OF MILES PLATE 6 tS. 18 30 31 (T CE -140- note: LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE GAGE AQUIFER AREA OF HYDRAULIC CONTINUITY BETWEEN THE GAGE AQUIFER AND THE OVERLYING GASPUR AQUIFER CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U S G S- DATUM STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTMCRN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY f^ DPO 0A^ CONTOURS ON THE TOP OF THE GAGE AQUIFER IN DOMINGUEZ GAP, WEST COAST BASIN SCALE 1/2 OF MILES PLATE 7 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE GAGE AND GARDENA AQUIFERS IN WEST COAST BASIN SCALE OF MILES 10 12 1962 PLATE 7 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE GAGE AND GARDENA AQUIFERS IN WEST COAST BASIN SCALE OF MILES 10 12 1962 s o LEGEND / O ^"^^■^^ BflSIN BOUNDARY BOUNDflRYOF THE GAGE AQUIFER BOUNDARY OF THE GARDEN A AQUIFER BOUNDARY OF THE GASPUR AQUIFER 20 CONTOURS ON TOP OF THE CAGE AND GARDENA AQUIFERS IDA5HED WHERE APPROXIMATED) 1^' I AREA OF HYDRAULIC CONTINUITY BETWEEN THE GAGE OR GARDENA I AQUIFERS AND THE GROUND SURFACE i; :;";;:;;;; :::i:;' area of hydraulic continuity between the gage aquifer Ei::::;; ;:;:;::;i;::j AND THE OVERLYING GASPUR AQUIFER NOTEr CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U.SGS DATUM C e ^ STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE GAGE AND GARDENA AQUIFERS IN WEST COAST BASIN SCALE OF MILES / ST 1T PLATE 8 18 ST 30 31 ST cc 0A^ --I60- LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON NOTE CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U S G S. DATUM. STATE OF CALtFORNIA DEPARTMENT OF WATER RESOURCES SOUTMC^N DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON IN DOMINGUEZ GAf? WEST COAST BASIN 1/2 SCALE OF MILES L3S. 4S. / ST 18 ^ ST. 30 31 ST (T (T Pe DP 0A^ PLATE 8 --I60- LEGEND BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON NOTE CONTOURS ARE REFERENCED TO MEAN SEA LEVEL USGS DATUM. STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTMCRN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON IN D0MIN6UEZ GAF? WEST COAST BASIN SCALE 1/2 OF MILES L E G E N BASIN BOUNDARY BOUNDARY OF THE GASPUR AQUIFER APPROXIMATE CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON NOTE CONTOURS ARE REFERENCED TO MEAN SEA LEVEL U SGS DATUM STATE OF CALlFOnNiA DEPARTMENT OF WATER RESOURCES SOOTMERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST SASIN, LOS ANGELES COUNTY CONTOURS ON THE TOP OF THE LOWER SEALING HORIZON IN DOMINGUEZ GAR WEST COAST BASIN SCALE OF MILES PLATE 9 STATE OF CALIFORNIA =ARTMENT OF WATER RESOURCES SOUTHERN DISTRICT COMMENDED WELL CONSTRUCTION AND ALING STANDARDS FOR PROTECTION OF OUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY LOCATION AND STATUS OF ■ WELLS IN WEST COAST BASIN SCALE OF MILES 10 12 PLATE 9 STATE OF CALIFORNIA =ARTMENT OF WATER RESOURCES SOUTHERN DISTRICT COMMENDED WELL CONSTRUCTION AND ALING STANDARDS FOR PROTECTION OF OUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY LOCATION AND STATUS OF • WELLS IN WEST COAST BASIN SCALE OF MILES 10 12 PLATE 9 LEGEND - BASIN BOUNDARY •Ai ACTIVE WELL QOl INACTIVE OR STAND-BY WELL OPi CAPPED WELL ©Ml DESTROYED WELL WEST COAST BASIN BARRIER PROJECT INJECTION WELLS STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY LOCATION AND STATUS OF KEY WELLS IN WEST COAST BASIN SCALE OF MILES PLATE 10 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN. LOS ANGELES COUNTY AREAS OF RECOMMENDED SEALING STANDARDS IN WEST COAST BASIN PLATE 10 STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAS OF RECOMMENDED SEALING STANDARDS IN WEST COAST BASIN AREft REQUIRING SEALING TO THE TOP OF THE GAGE OR GARDENA AQUIFERS ZONE 3, AREA REQUIRING MULTIPLE SEALING STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES SOUTHERN DISTRICT RECOMMENDED WELL CONSTRUCTION AND SEALING STANDARDS FOR PROTECTION OF GROUND WATER QUALITY IN WEST COAST BASIN, LOS ANGELES COUNTY AREAS OF RECOMMENDED SEALING STANDARDS IN WEST COAST BASIN SCALE OF MILES I Q I 2 APPr]I\rD]X A LIST OF REFrJRENCiJS ;^PENDIX A List of References The following reports, bulletins, and abstracts were reviewed during the course of this investigation. While this list is by no means exhaustive, the publications cited were used as the primary background materials in this study. American Association of Petroleum Geologists Bulletin. "Code of Strati- graphic Nomenclature." Vol. k^, IJo. 5- ^^J I961 American Association of Petroleum Geologists, Pacific Section. "A Guide to the Geology and Oil Fields of the Los Angeles and Ventura Regions." I958. American Geological Institute. "Glossary of Geology and Related Sciences." The National Academy of Sciences - National Research Board Council, Washington, D. C. 195?. Associated Drilling Contractors of tae State of California. "Recommended Standards for Preparation of V/ater \Jell Construction Specifications." September I96O. California State Department of Natural Resources, Division of Mines. "Geologic Formations and Economic Development of the Oil and Gas Fields of California." Bulletin II8. 19^3. "Geology of Southern California." Bulletin 170. 195^. California State Depairtment of Public Works, Division of Water Resources, "South Coastal Basin Investigation, Quality of Irrigation Waters," Bulletin No. ifO. I933. "South CoastaQ. Basin Investigation, Detailed Analyses Showing Quality of Irrigation Waters." Bulletin No. i40A. 1933« "South Coastal Basin Investigation, Geology and Ground Water Storage Capacity of Valley Fill." Bulletin No. h3. 193^. "Sea-Water Intrusion into Ground Water Basins Bordering the California Coast and Inland Bays." Report No. 1. December 1950- "Report of Referee, California V/ater Service Company, A Corporation et al., V. City of Corapton, et al.. Case No. 506806, Superior Court, Los Angeles County." June 1952. "Investigation of Los Angeles River." Code No. 52-^4-2. September 1952. A-1 "South CoastaJ. Basin Investigation, Records of Groiind Water Levels at Wells." Bulletin No. 39 and annual supplements A through W, 1932 txirough 1956. "Abstract of Laws and Recommendations Concerning Water Well Con- struction and Sealing in the United States." Water Quality- Investigations i^eport No, 9. April 1955 • California State Water Resources Board. "Los Angeles County Land and Water Use Siurvey, 1955." Bulletin No. 2k. June I956. California State Department of V/ater Resources. "Sea-Water Intrusion in California." Bulletin No. 63. November I958; Appendix B, March 1957; Appendixes C, D, a], April I960. "Water Supply Conditions in Southern California During I955-I956," Bulletin No. 39-56. March 1957. "Water Supply Conditions in Southern California During 1956-57," Bulletin No. 39-57, June I958, "Recommended V/ater Well Construction and Sealing Steindards Mendocino Coxinty." November 1958. "Report on Proposed Central and West Basin Water Replenishment District." July I959, "Planned Utilization of the Grovind Water Basins of the Coastal Plain of Los Angeles Co\mty, " Appendix A, "Ground Water Geology," Bulletin No. IQi^. June I961. "Report on Watermaster Service in West Coast Basin Watermaster Service Area, Los Angeles County, California, for Period June 1, i960 through May 3I, I961," August I961, — -- "Recommended Standards for Water Well Construction and Sealing of Abandoned Wells, State of California, Revised Drafl; of Bulletin No, 7U. May I962, California State Water Rights Board. "Report of Referee, California Water Service Company, a Corporation et al., v. City of Conrpton, et eQ.,, Case No, 506806, Superior Coiort, Los Angeles County," May I961, City of Anaheim, Water Division." Specifications for Backfilling of Abandoned Wells in the City of Anaheim." Ordinance No. I529, Chapter 10,20, March I962. Belong, J, H,, Jr, "The Paleontology eind Stratigraphy of the Pleistocene at Signal Hill, Long Beach, California," Transactions San Diego Society of Natural History, Vol. IX, No, 25, 1941. A-2 Hoots, H, W, "Geology of the Eastern Part of the Santa Monica Motmtains, Los Angeles County, California," United States Geological Survey Professional Paper 165-C, I93I, Meinzer, 0, "Hydrology." Dover Publications, New York. 19^2. MendenhsLll, W. C, "Development of Undergroimd Waters in the Central Coastal Plain Region of Southern California." United States Geological Survey Water-Supply and Irrigation Paper No, I38. 1905. — — "Development of IMderground Waters in the Western Coastal Plain Region of Southern California." United States Geological Survey Water-supply and Irrigation Paper No. 139. 1905. Metropolitan Water District of Southern California. "Twenty-second Annioal Report, i960," Piper, A, M,, and others, "Native and Contaminated Ground Waters in the Long Beach - Santa Ana Area, California," United States Geological Survey Open File Report, August 19^6, "Native and Contaminated Ground Waters in the Long Beach - Santa Ana Area, California," United States Geological Survey Water-Supply Paper II36, 1953. Poland, J, F,, and others, "Geologic Features in the Coastal Zone of Long Beach - Santa Ana Area, California, with Particular Respect to Groimd Water Conditions," United States Geological Survey Open File Report, May 19^5. "Ground Water Geology of the Coastal Zone Long Beach - Santa Ana Area, California," United States Geological Survey Water-Supply Paper II09. 1956. "Ground Water Investigation along the Rio Hondo and Lower Ix)s Angeles Rivers, Los Angeles County, California - Progress Report No, 2," United States Geological S\irvey Open File Report, January 19^, "Hydrology of the Long Beach - Santa Ana Area, California, with Special Reference to the Watertightness of the Newport- Inglewood. Structural Zone," United States Geological Survey Open File Report. June 19*+^. Poland, J. F., Garrett, A. A., and Slnnot, A. "Geology, Hydrology and Chemical Character of Ground Waters in the Torrance - Santa Monica Area, Los Angeles Coiinty, California." United States Geological S\arvey Open File Report. May ISkQ, "Geology, Hydrology, and Chemical Character of the Ground Waters in the Torrance - Sajita Monica Area, California." United States Geological Svirvey Water-Supply Paper 1^461. 1959* A-3 Poland, J. F. , and Sinnott, A. Hydrology of the Long Beach - Santa Ana Area with Special Reference to the Watertightness of the Newport- Inglewood Structural Zone." United States Geological. Survey Water- Supply Paper 11^71. I959. United States Public Heeath Service. "Public Health Service Drinking Water Standrads 19k6," Public Health Records, Vol. 61, No. U. March 19k6, Woodring, W. P., Bramlette, M. N. , and Kew, W. S. W. "Geology and Paleon- tology of Palos Verdes Hills, California." United States Geological Survey Professional Paper 207. 191*6. A-k APPENDIX B DEFINITION OF TERMS APPENDIX B DEFINITION OF TERMS The following terms are defined as used in this report. Active Well - An operating water well. Annular Space - The space between two well casings or a well casing and the drilled hole. Anticline - A fold in rocks in irtiich the strata dip in opposite direc- tions from a common ridge or aixis, like the roof of a house. Aquiclude - A formation or part of a formation i^ich, although porous and capable of absorbing water slowly, will not transmit it fast enough to furnish an appreciable supply for wells or springs. Aquifer - A formation or part of a formation which transmits water in sufficient quantity to supply pumping wells or springs. Capped Well - A water well from which the pump has been removed, and a permanent or locked cap insteLLled on top of the casing. Casing - A tubular retaining structure, generally metal or concrete, which is instailled in the excavated hole to maintain the well opening. Conductor Pipe - A tubular retaining structure installed between the drilled hole and the inner casing, generally in the upper portion of a well. Confined Ground Water - A body of ground water overlain by materied. suffi- ciently inipervious to sever free hydraulic connection with overlying ground water except at the intake. Confined ground water moves in conduits under pressure due to the difference in head between the intake and discharge areas of the confined water body. B-1 Connate Water - Water entrapped in the interstices of a sedimentaiy rock at the time it was deposited. These waters may be fresh, brackish, or saline in character. Because of the dynamic geologic and hydro- logic conditions in California, this definition has been altered in practice to apply to water in. older formations, even though the water in these formations may have been altered in quality since the rock was originally deposited. Contamination - Defined in Section I3OO5 of the California Water Code: "... an impairment of the quality of the waters of the State by sewage or industrial waste to a degree which creates an actual hazard to public health through poisoning or through the spread of disease . . . . " Jurisdiction over matters regarding contamination rests with the California Department of Public Health and local health officers. Degradation - Impairment in the quality of water due to causes other thaui disposal of sewage and industrial waste. Destroyed Well - A water well which has been filled or plugged so that it will not produce water. A properly destroyed well is one vrtiich has been destroyed so that it will not produce water nor act as a conduit for the movement of water. Deterioration - An impairment of water quality. Drilled Well - A well for which the hole is generally excavated by mechanical means such as the rotary or cable tool methods. Dug Well - A well for which the hole is generally excavated by hand tools, and which is usually of shallower depth and larger diameter than drilled wells. B-2 Equivalents Per Million (epm) - Equivalent weights of solute contained In one million parts by weight of solution. For practical pur- poses, epm Is the same as mllllequlvalents per liter. Filler Material - An Inert, Impervious material such as portland cement grout, Impervious native soil, clay, or other suitable Impervious material. Gravel Packed Well - A well In which a gravel envelope is placed in the annular space to increase the effective diameter of the well, and to prevent fine-grained sediments from entering the well. Ground Water - That part of the subsurface water \rtilch is in the zone of saturation. Ground Water Basin - An area underlain by one or more permeable forma- tions capable of furnishing a substantial water supply. Impairment - A change in quality of water \rtiich makes it less suitable for beneficlaJ. use. Impermeable - Having a texture that does not permit water to Hove through it perceptibly under the head differences ordinarily found in subsurface water. Impervious Grout - A durable cementing agent, such as portland cement, used for sealing water wells during construction or destruction. Inactive or Stand-by Well - A water well equipped with a pump but not in use. Industrial Waste - Defined in Section I3OO5 of the California Water Code: "... any and all liquid or solid waste substance, not sew- age, from any producing, manufacturing or processing operation of whatever nature." B-3 Liner - A section of casing of reduced diameter permanently installed within an existing casing to seal openings in the existing casing. Overdreift - The average annual decrease in the amount of ground water in storage that occurs during a long time period, under a particular set of physical conditions affecting the supply, use, and disposal (including extractions) of water in the ground water basin. Packer - A device placed in a well which plugs or seals the well at a specific point. Parts Per Million (ppm) - One weight of solute per one million weights of solution at 20° C. Permeability - The capacity of a rock to transmit a fluid. The degree of permeability depends upon the size and shape of the pores, the size and shape of their interconnections, and the extent of the latter . Pollution - Defined in Section I3OO5 of the California Water Code: "... an impairment of the quality of the waters of the State by sewage or industrial waste to a degree which does not create an actual hazard to the public health but which does adversely and unreasonably affect such waters for domestic, industrial, agricul- tural, navigational, recreational or other beneficial use, or vrtiich does adversely and unreasonably affect the ocean waters and bays of the State devoted to public recreation." Regional tfeiter Pollution Control Boards are responsible for prevention and abatement of pollution. Pressure Grouting - A method of forcing impervious grout into specific portions of a well, such as the annular space, for sealing purposes. B-k Sealing Horizon - The boundary below the Eturface of the ground deter- mined by this Investigation to be the level to which a specific well should be sealed, employing the standards set forth in this report, to prevent any undesirable movement of ground water. Safe Yield - The average annual amount of ground water that could be extracted from a ground water basin over a long time period which would not effect a long time net change in storage of ground water; the extractions must occur under a particular set of physlcaJ. conditions affecting the water supply, use, and dispossil of water in the ground water basin. Sewage - Defined in Section I3OO5 of the California Water Code: "... any and all waste substance, liquid or solid, associated with human habitation, or which contains or may be contaminated with human or animal excreta or excrement, offal, or any feculent matter." Sync line - A fold In rocks in \rtilch the strata dip inward from both sides toward a common plane or axis, like the inverted roof of a house. Total Dissolved Solids (TDS) - The dry residue from the dissolved matter in an aliquot of a water sample remaining after evaporating of the sample at a definite temperature. Total Dissolved Solids (TDS) By Summation - The TDS determined by sum- ming the total dissolved constituents less one-half the bicarbonate ion, Transmissibillty - The characteristic property of the entire saturated portion of an aquifer to transmit water. Waste Water - The water that has been put to some use or uses and has been disposed of, commonly to a sewer or wasteway. It may be liquid industrial waste, or sewage, or both. B-5 APPEKDIX C V7ELL I^IUMBERBIG SYSTlll APPENDIX C Well Numbering System The well numbers used in this report are referenced by vise of the IMited States Public Land Survey System, and to the San Bernardino Base and Meridiem. The well identification consists of a township, ran g e, and section number, a letter which indicates the ItO-acre lot in which the well is located, and a final number which indicates the identity of the particular well within the lot. The subdivision of a section is shown below: D C B A E F G ■> H M L K J N P Q R For Example, 3S/li