Geology and Ground Water in Russian River Valley Areas and in Round, Laytonville and Little Lake Valleys Sonoma and Mendocino Counties, California By G. T. CARDWELL GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1548 Prepared in cooperation with the California Department of Jf^ater Resources UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Abstract_____________________________________________________ 1 Introduction... _______________________________________________ 1 Purpose and scope_____-________________-___-_______----__-___- 1 Location of the area______________________-___________-___ ___ 2 Previous investigations.________________________________________ 2 Methods of investigation__________________________.____________ 4 Acknowledgments- _____-___-________-____-_---_-_------._----_ 5 Well-numbering system________________________________________ 5 Geography______________________________________________________ 6 Physiography and drainage_____________________________________ 6 Description of subareas_______________________________________ 8 Climate.____________________________________________________ 11 General features__-__-_-_____---__-_-_----__-__--_-__------ 11 Precipitation..._________________________________________ 12 Cultural features and natural resources.______________________ 12 Water utilization_______________________________________ 15 Source of water supplies__________________________ _ 17 General geology _________________________________________ 18 Summary of stratigraphy and occurrence of ground water._________ 18 Summary of structural control of topography.____________________ 19 Geologic history________________________________ 22 Geology and ground water of lower and middle Russian River basins - 23 Lower Russian River valley________________ ___ __ 23 Geology and water-bearing character of rock units ______ ___ 23 Franciscan and Knoxville Formations______________ ____ 24 Alluvium and river-channel deposits.____________________ 24 Ground water_______.____________________________ 25 Healdsburg area________________________________ 29 Geology and water-bearing character of rock units________ __ 29 Franciscan and Knoxville Formations____________________ 29 Merced Formation___________________________________ 30 Glen Ellen Formation_________________________ 30 Terrace deposits___________________________________ 31 Alluvium and river-channel deposits.____________________ 32 Ground water__-____-___________________________________ 34 Alexander Valley______________________________________________ 39 Geology and water-bearing character of rock units.____________ 39 Franciscan and Knoxville Formations.___________________ 39 Cretaceous(?) conglomerate-____________-____-_________- 39 Sonoma Volcanics___________________-___-____-_______- 40 Glen Ellen Formation_______________________________ 40 Terrace deposits_____________________________________ 41 Alluvium and river-channel deposits.____________________ 42 Ground water_____________________________________________ 42 in IV CONTENTS Geology and ground water, etc. Continued Pag« Cloverdale Valley_____________________-_--------__________-__ 47 Geology and water-bearing character of rock units..___________ 47 Franciscan and Knoxville Formations.___________________ 47 Terrace deposits_____________________________________ 47 Alluvium and river-channel deposits _____________________ 48 Ground water___________________________________ ________ 49 Geology and ground water of the upper Russian River basins-__________ 54 Sanel Valley area_________________-_____-_-_---_-_-___________- 54 Geology and water-bearing character of rock units.____________ 54 Franciscan and Knoxville Formations._________________ 54 Continental deposits__------_-_----_~_-_~---_-_-__---_- 55 Terrace deposits_____________________________________ 56 Dissected alluvium____________________________________ 56 Alluvium and river-channel deposits _____________________ 57 Ground water_____________________________________________ 58 Ukiah Valley area.__________________.____________ 62 Geology and water-bearing character of rock units..___________ 62 Franciscan and Knoxville Formations____________________ 63 Continental deposits______-_-----------_------_---____- 63 Terrace deposits___ _________-______-__-___-________ 65 Dissected alluvium.___________________________________ 66 Alluvium and river-channel deposits.____________________ 66 Ground water__________________________-_-_-_-_____-_____- 67 Potter Valley.._________________________________ 73 Geology and water-bearing character of rock units...__________ 73 Franciscan and Knoxville Formations..__________________ 73 Continental deposits.________-________-_-_-_-_-_-_----- 73 Terrace deposits-___-_-_-----_-------~--_-----_-------- 74 Alluvium_____ ________________________________________ 75 Ground water______________________----_---_-__-----__--_- 75 Geology and ground water of the northern Mendocino County basins-___ 79 Round Valley____________________________________ 79 Geology and water-bearing character of rock units-____________ 79 Structure and geologic history_________________________ 79 Franciscan and Knoxville Formations.-__________________ 81 Continental deposits----------------------------------- 81 Alluvium and river-channel deposits-____________________ 82 Ground water______________-__-__-_-_--------_------_---_- 84 Laytonville Valley._-_________________________-___-___-_---_-_- 92 Geology and water-bearing character of rock units____________ 92 Structure and geologic history_________________________ 92 Franciscan and Knoxville Formations.___________________ 93 Continental deposits____-__-----__---_---------_------- 94 Terrace deposits.____________________________________ 94 Alluvium and river-channel deposits--------------------- 95 Ground water......_______________________________________ 96 Little Lake Valley____________________________ 101 Geology and water-bearing character of rock units_____________ 101 Structure and geologic history_________________________ 101 Franciscan Formation________________________________ 102 Continental deposits_______--_--_--_---_--__----------- 102 Alluvium _____________________________________________ 104 Ground water________________________-____________-------- 105 CONTENTS V Page Selected bibliography. _____________________________________________ 110 Description of wells and springs, Russian River valley area_____________ 111 Logs of wells, Russian River valley area____________________________ 123 Chemical analyses of water, Russian River valley area_________________ 131 Description of wells and springs, Mendocino County___________________ 136 Logs of wells, Mendocino County_________-_--__-_--__-_-_----_--_-_- 142 Chemical analyses of water, Mendo cino County _______________________ 145 Miscellaneous streamflow measurements, Mendocino County____________ 148 Index._______-_________-____-_______________-__-__-_--__-_-----_- 151 ILLUSTRATIONS [Plates are In pocket] PLATE 1-3. Geologic maps showing location of wells: 1. Lower and middle Rusisan River valley areas. 2. Upper Russian River valley area. 3. Round Valley. 4. Map showing water-level contours and area of flowing wells in Round Valley, Mendocino County, Calif. 5, 6. Geologic maps showing location of wells: 5. Laytonville Valley area. 6. Little Lake Valley. Page FIGURE 1. Index map showing location of areas described._________ 3 2. Well-numbering system.______________________________ 5 3. Fluctuation of water levels in the Healdsburg area, and monthly precipitation at Healdsburg-_--__-_-_-_-_____ 13 4. Graphical representation of chemical analyses of waters in the lower and middle Russian River valley areas-_____ 27 5. Fluctuation of water levels in Alexander Valley___________ 44 6. Graphical representation of chemical analyses of water from three wells in Clo verdale Valley __________________ 52 7. Fluctuation of water levels in the Sanel Valley area_______ 59 8. Graphical representation of chemical analyses of waters in Sanel, Ukiah, and Potter Valley areas-_______________ 61 9. Fluctuation of water levels in Ukiah Valley 69 10. Fluctuation of water levels in Potter Valley-_____________ 76 11. Geologic section of upper parfc of alluvium in Round Valley. 83 12. Fluctuation of water levels in Round Valley- _____________ 86 13. Graphical representation of chemical analyses of waters in Round, Laytonville, and Little Lake Valleys.___-__-___ 91 14. Geologic section across Laytonville Valley _______________ 95 15. Fluctuation of water levels in Laytonville Valley.-.------ 98 16. Fluctuation of water levels in Little Lake Valley-_-___-_- 106 VI CONTENTS TABLES Page TABLE 1. Climatological data from selected Weather Bureau stations in Sonoma and Mendocino Counties, Calif., through 1955_. ___________________________________________ 11 2. Public water supplies_____________-________________.__ 16 3. Stratigraphic units and their water-bearing character in Russian River valley areas, California.--_____________ 20 4. Estimated ground-water storage capacity in the lower Russian River valley_________________________ 26 5. Summary of chemical character of ground water in the lower and middle Russian River valley areas__________ 28 6. Estimated withdrawals for irrigation in the Healdsburg area, 1954_________________________.__________ 37 7. Summary