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A Three-Dimensional Numerical Model of Predevelopment Conditions in the Death Valley Regional Ground-Water Flow System, Nevada and California

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A Three-Dimensional Numerical Model of Predevelopment Conditions in the Death Valley Regional Ground-Water Flow System, Nevada and California Prepared in cooperation with the OFFICE OF ENVIRONMENTAL RESTORATION AND WASTE MANAGEMENT, U.S. DEPARTMENT OF ENERGY NATIONAL NUCLEAR SECURITY ADMINISTRATION, NEVADA OPERATIONS OFFICE, under Interagency Agreement DE-AI08-96NV11967 A Three-Dimensional Numerical Model of Predevelopment Conditions in the Death Valley Regional Ground-Water Flow System, Nevada and California Water-Resources Investigations Report 02–4102 U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY A Three-Dimensional Numerical Model of Predevelopment Conditions in the Death Valley Regional Ground-Water Flow System, Nevada and California By Frank A. D'Agnese, Grady M. O’Brien, Claudia C. Faunt, Wayne R. Belcher, and Carma San Juan U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 02–4102 Prepared in cooperation with the OFFICE OF ENVIRONMENTAL RESTORATION AND WASTE MANAGEMENT, U.S. DEPARTMENT OF ENERGY, NATIONAL NUCLEAR SECURITY ADMINISTRATION, NEVADA OPERATIONS OFFICE, under Interagency Agreement DE–AI08–96NV11967 Denver, Colorado 2002 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: Chief, Yucca Mountain Project Branch U.S. Geological Survey U.S. Geological Survey Information Services Box 25046, Mail Stop 421 Box 25286 Denver Federal Center Denver Federal Center Denver, CO 80225-0046 Denver, CO 80225 CONTENTS Abstract.................................................................................................................................................................................. 1 Introduction............................................................................................................................................................................ 2 Purpose and Scope....................................................................................................................................................... 4 Site Description ..................................................................................................................................................................... 5 Physiography ............................................................................................................................................................... 5 Climate......................................................................................................................................................................... 5 Soils and Vegetation..................................................................................................................................................... 6 Geologic Setting .......................................................................................................................................................... 7 Proterozoic and Paleozoic Time ........................................................................................................................ 8 Mesozoic Time .................................................................................................................................................. 8 Tertiary and Quaternary Time............................................................................................................................ 8 Tertiary and Quaternary Tectonics..................................................................................................................... 10 Hydrology .................................................................................................................................................................... 10 Land and Water Use..................................................................................................................................................... 13 Ground-Water System............................................................................................................................................................ 13 System Boundaries ...................................................................................................................................................... 13 Hydrogeologic Framework .......................................................................................................................................... 14 Hydrogeologic Units.......................................................................................................................................... 14 Hydrogeologic Structures .................................................................................................................................. 16 Source, Occurrence, and Movement of Ground Water................................................................................................ 17 Northern Death Valley Subregion...................................................................................................................... 18 Central Death Valley Subregion ........................................................................................................................ 21 Pahute Mesa–Oasis Valley Ground-Water Basin.....................................................................................23 Ash Meadows Ground-Water Basin ........................................................................................................ 23 Alkali Flat–Furnace Creek Ground-Water Basin..................................................................................... 23 Southern Death Valley Subregion...................................................................................................................... 24 Ground-Water System Budget Components................................................................................................................ 26 Estimates of Ground-Water Discharge .............................................................................................................. 26 Estimates of Recharge ....................................................................................................................................... 29 Numerical Model of Regional Ground-Water Flow .............................................................................................................. 32 Numerical Modeling Difficulties, Simplifications, and Assumptions......................................................................... 32 Numerical Model Selection ......................................................................................................................................... 34 Nonlinear Regression Objective Function......................................................................................................... 34 Parameter Definition.......................................................................................................................................... 35 Parameter Sensitivities....................................................................................................................................... 35 Model Construction ..................................................................................................................................................... 36 Grid Definition................................................................................................................................................... 36 External Boundary Conditions .......................................................................................................................... 36 Representation of the Hydrogeologic System ................................................................................................... 39 Hydrogeologic Units................................................................................................................................ 39 Hydrogeologic Structures ........................................................................................................................ 39 Evapotranspiration and Spring Flow ....................................................................................................... 39 Recharge .................................................................................................................................................. 40 Observation Data ............................................................................................................................................... 42 Hydraulic-Head Observations.................................................................................................................. 44 Ground-Water Discharge Observations ................................................................................................... 48 Model Calibration........................................................................................................................................................ 49 Conceptual Model Variations ............................................................................................................................ 49 Location and Type of Boundary Conditions............................................................................................ 49 Definition of Discharge Areas ................................................................................................................. 50 Definition of Recharge Areas
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