AQUIFER SYSTEMS IN THE GREAT BASIN REGION

OF NEVADA, UTAH, AND ADJACENT STATES 

1 SUMMARY REPORT

PROFESSIONAL PAPER 1409-A
Availability of Publications of the U.S. Geological Survey

Order U.S. Geological Survey (USGS) publications from the 

offices listed below. Detailed ordering instructions, along with 

prices of the last offerings, are given in the current-year issues 

of the catalog "New Publications of the U.S. Geological 

Survey."

Books, Maps, and Other Publications 

By Mail

Books, maps, and other publications are available by mail 

from 

USGS Information Services 

Box 25286, Federal Center 

Denver, CO 80225

Publications include Professional Papers, Bulletins, WaterSupply Papers, Techniques of Water-Resources Investigations, 

Circulars, Fact Sheets, publications of general interest, single 

copies of permanent USGS catalogs, and topographic and 

thematic maps.

Over the Counter

Books, maps, and other publications of the U.S. Geological 

Survey are available over the counter at the following USGS 

Earth Science Information Centers (ESIC's), all of which are 

authorized agents of the Superintendent of Documents:

 Anchorage, Alaska Rm. 101, 4230 University Dr.

 Denver, Colorado-Bldg. 810, Federal Center

 Menlo Park, California-Rm. 3128, Bldg. 3, 

345 Middlefield Rd.

 Reston, Virginia-Rm. 1C402, USGS National Center, 

12201 Sunrise Valley Dr.

 Salt Lake City, Utah-2222 West, 2300 South (books and 

maps available for inspection only)

 Spokane, Washington-Rm. 135, U.S. Post Office 

Building, 904 West Riverside Ave.

 Washington, D.C.-Rm. 2650, Main Interior Bldg., 

18th and C Sts., NW.

Maps only may be purchased over the counter at the following 

USGS office:

 Rolla, Missouri 1400 Independence Rd.

Electronically

Some USGS publications, including the catalog "New Publications of the U.S. Geological Survey" are also available electronically on the USGS's World Wide Web home page at 

http://www.usgs.gov

Preliminary Determination of Epicenters

Subscriptions to the periodical "Preliminary Determination of 

Epicenters" can be obtained only from the Superintendent of

Documents. Check or money order must be payable to the 

Superintendent of Documents. Order by mail from 

Superintendent of Documents 

Government Printing Office 

Washington, DC 20402

Information Periodicals

Many Information Periodicals products are available through 

the systems or formats listed below:

Printed Products

Printed copies of the Minerals Yearbook and the Mineral Commodity Summaries can be ordered from the Superintendent of 

Documents, Government Printing Office (address above). 

Printed copies of Metal Industry Indicators and Mineral Industry Surveys can be ordered from the Center for Disease Control 

and Prevention, National Institute for Occupational Safety and 

Health, Pittsburgh Research Center, P.O. Box 18070, Pittsburgh, PA 15236-0070.

Mines FaxBack: Return fax service

1. Use the touch-tone handset attached to your fax machine's 

telephone jack. (ISDN [digital] telephones cannot be used with 

fax machines.)

2. Dial (703) 648^999.

3. Listen to the menu options and punch in the number of your 

selection, using the touch-tone telephone.

4. After completing your selection, press the start button on 

your fax machine.

CD-ROM

A disc containing chapters of the Minerals Yearbook (1993- 

95), the Mineral Commodity Summaries (1995-97), a statistical compendium (1970-90), and other publications is updated 

three times a year and sold by the Superintendent of Documents, Government Printing Office (address above).

World Wide Web

Minerals information is available electronically at 

http://minerals.er.usgs.gov/minerals/

Subscription to the catalog "New Publications of the U.S. 

Geological Survey"

Those wishing to be placed on a free subscription list for the 

catalog "New Publications of the U.S. Geological Survey" 

should write to 

U.S. Geological Survey 

903 National Center 

Reston, VA 20192
Aquifer Systems in the Great Basin Region 

of Nevada, Utah, and Adjacent States 

Summary Report

By JAMES R. HARRILL and DAVID E. PRUDIC

REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1409-A

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1998
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

THOMAS J. CAS ADEVALL, Acting Director

Any use of trade, product, or firm names in this publication is for

descriptive purposes only and does not imply endorsement by the

U.S. Government

Library of Congress Cataloging-in-Publication Data

Harrill, James R.

Aquifer systems in the Great Basin region of Nevada, Utah, and adjacent states : summary report / by 

James R. Harrill and David E. Prudic.

p. cm. (Regional aquifer-system analysis Great Basin, Nevada-Utah) (U.S. Geological Survey 

professional paper ; 1409-A)

Includes bibliographical references. 

Supt. of Docs. no.: I 19.16 :1409-A

1. Aquifers Great Basin. I. Prudic, David E. II. Title. III. Series. IV. Series : U.S. Geological 

Survey professional paper; 1409-A. 

GB1199.3.G73H37 1998

551.49'0979 dc21 98-34846

CIP 

ISBN 0-607-90058-X

For sale by U.S. Geological Survey, Branch of Information Services, 

Denver Federal Center, Box 25286, Denver, CO 80225-0286
FOREWORD

THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM

The Regional Aquifer-System Analysis (RASA) program was started in 1978 

following a congressional mandate to develop quantitative appraisals of the major 

ground-water systems of the United States. The RASA program represents a 

systematic effort to study a number of the Nation's most important aquifer 

systems, which in aggregate underlie much of the country and which represent an 

important component of the Nation's total water supply. In general, the 

boundaries of these studies are identified by the hydrologic extent of each system 

and accordingly transcend the political subdivisions to which investigations have 

often arbitrarily been limited in the past. The broad objective for each study is to 

assemble geologic, hydrologic, and geochemical information, to analyze and 

develop an understanding of the system, and to develop predictive capabilities 

that will contribute to the effective management of the system. The use of 

computer simulation is an important element of the RASA studies, both to develop 

an understanding of the natural, undisturbed hydrologic system and the changes 

brought about in it by human activities, and to provide a means of predicting the 

regional effects of future pumping or other stresses.

The final interpretive results of the RASA program are presented in a series of 

U.S. Geological Survey Professional Papers that describe the geology, hydrology, 

and geochemistry of each regional aquifer system. Each study within the RASA 

program is assigned a single Professional Paper number, and where the volume of 

interpretive material warrants, separate topical chapters that consider the 

principal elements of the investigation may be published. The series of RASA 

interpretive reports begins with Professional Paper 1400 and thereafter will 

continue in numerical sequence as the interpretive products of subsequent studies 

become available.

1.

Thomas J. Casadevall 

Acting Director
PREFACE

The Regional Aquifer-System Analysis of the Great Basin was conducted by U.S. 

Geological Survey personnel in Nevada and Utah. A supporting contract to study recharge 

processes was awarded to the Desert Research Institute of the University of Nevada. During 

the initial years of the study, the U.S. Air Force conducted a siting investigation for the 

proposed MX missile system in parts of Nevada and Utah. The Air Force allowed ready 

access to this data, which provided much useful information for the RASA program. In 

addition, valuable information was provided by many State and local agencies throughout 

the Great Basin. Their contributions are an integral part of this investigation, and without 

them this report would not have been possible.
CONTENTS

Page

Abstract................................................................................................... Al

Introduction........................................................................................... 2

Regional analysis of aquifer systems in Great Basin study

Background................................................................................

Major objectives.........................................................................

Approach...................................................................................

Purpose and scope of Professional Papers 1409-A

through 1409-H................................................................... 4

Other reports prepared for this study.................................... 5

Previous studies.............................................................................. 5

Hydrologic environment................................................................ 6

Physiography............................................................................. 6

Drainage..................................................................................... 6

Hydrographic areas.................................................................. 7

Climate........................................................................................ 7

Ground-water development.......................................................... 7

Geologic setting..................................................................................... 7

Depositional environments........................................................... 7

Structural features........................................................................... 9

Hydrogeology........................................................................................ 15

Carbonate-rock aquifers................................................................. 15

Basin-fill aquifers............................................................................ 17

Volcanic-rock aquifers.................................................................... 19

Page

Hydrogeology Continued

Barriers to regional ground-water flow....................................... A19

Ground-water recharge........................................................................ 23

Ground-water discharge...................................................................... 25

Regional ground-water flow............................................................... 27

Concepts of regional flow.............................................................. 27

Potential for regional ground-water flow.................................... 28

Description of regional systems.................................................... 28

Simulation of ground-water flow....................................................... 35

Simulation of regional ground-water flow in carbonate-rock

province...................................................................................... 35

Fish Springs flow system............................................................... 42

Comparison of simulation results from Fish Springs 

model and results from carbonate-rock province 

model for corresponding area .......................................... 42

Simulated water budgets......................................................... 42

Transmissivity distributions.................................................... 48

Simulated hydraulic heads...................................................... 48

Simulation of ground-water flow in basin-fill aquifers............. 49

Water quality and geochemistry......................................................... 56

Smith Creek Valley basin-fill aquifer............................................ 56

Carbonate-rock aquifers of southern Nevada............................. 58

References cited..................................................................................... 61

ILLUSTRATIONS

Page 

FIGURES 1-6. Maps showing:

1. Location and general features of study area, Great Basin Regional Aquifer System ......................................................... A3

2. Hydrographic areas and subareas of Great Basin study area................................................................................................. 8

3. Estimated ground-water withdrawals for 1975 in hydrographic areas and subareas of Great Basin study area.......... 13

4. Occurrence of depositional facies of early Mesozoic and older rocks in Great Basin study area..................................... 14

5. Selected geologic features of Great Basin study area............................................................................................................... 16

6. Hydrogeologic units of Great Basin study area........................................................................................................................ 18

7. Idealized sections showing basin geometry for six representative hydrographic areas in Great Basin study area.................... 21

8-10. Maps showing:

8. Potential barriers to regional ground-water flow in carbonate-rock province.................................................................... 22

9. Major source areas for ground-water recharge......................................................................................................................... 24

10. Areas where estimates of recharge were used to define relation between recharge and mean annual precipitation

in excess of 8 inches ................................................................................................................................................................. 26

11. Graph showing relation between recharge and mean annual precipitation volume where precipitation rate exceeds 8

inches per year........................................................................................._ 28

12. Map showing locations of large springs and areas of ground-water discharge by evapotranspiration...................................... 34

13. Schematic diagrams showing ground-water flow from recharge areas in mountains to discharge areas on basin floors.

A, Generalized hydrogeologic section. B, Finite-difference computer model. C, Water budget within area encompassed

by deep-flow region on basis of computer-model output............................................................................................................... 36
VI CONTENTS

Page 

FIGURES 14-20. Maps showing:

14. Regional ground-water flow potential....................................................................................................................................... A38

15. Major ground-water flow systems ............................................................................................................................................. 40

16. Representative basins and regional systems used to model ground-water flow in Great Basin Regional AquiferSystem Analysis ...................................................................................................................................................................... 43

17. High transmissivity in lower model layer in relation to springs used in model simulations and to boundary of

central corridor of thick carbonate rocks in south-central Nevada................................................................................. 44

18. Deep-flow regions and subregions in carbonate-rock aquifers (lower model layer) based on simulated hydraulic

heads....................................................................................................................................................................^ 45

19. Transmissivity in lower layers of ground-water flow models for Fish Springs and carbonate-rock province............... 50

20. Simulated water-level contours for Fish Springs ground-water flow system and for comparable area of carbonaterock province, upper and lower model layers.................................................................................................................... 52

21. Sketches showing hydrogeologic section and three-dimensional finite-difference model of basin-fill aquifer........................... 54

22-24. Maps showing:

22. Dissolved-solids concentration in water from principal aquifers in Great Basin study area............................................ 57

23. Location and general hydrologic features of Smith Creek Valley Hydrographic Area...................................................... 58

24. Ground-water flow (rate and direction) in carbonate-rock aquifers of southern Nevada................................................. 60

TABLES

Page

TABLE 1. Hydrographic areas and flow systems within study area, Great Basin Regional Aquifer System.......................................................... A10

2. Aquifers and confining units in Great Basin study area................................................................................................................................ 20

3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8

inches in Great Basin study area ................................................................................................................................................................... 29

4. Selected characteristics of major ground-water flow systems in Great Basin study area......................................................................... 41

5. Simulated predevelopment ground-water flow budgets for five deep-flow regions of carbonate-rock province............................... 46

6. Predevelopment ground-water budgets from Fish Springs ground-water flow model and from carbonate-rock province

ground-water flow model for comparable area......................................................................................................................................... 47

7. Selected characteristics and hydraulic properties of five basin-fill aquifer models used in this study.................................................. 55

8. Simulated responses to pumping scenario where pumping equals estimated natural recharge and discharge and is distributed

strategically to capture discharge........................................................ 56

9. Flow velocities in carbonate-rock aquifers, southern Nevada, calculated from adjusted carbon-14 ages and hydrologic data........ 61

CONVERSION FACTORS, VERTICAL DATUM, AND WATER-QUALITY UNITS

Multiply By To obtain

acre 0.4047 hectare

acre-foot (acre-ft) 0.001233 cubic hectometer

cubic foot per second (ft3/s) 0.02832 cubic meter per second

foot (ft) 0.3048 meter

foot per day (ft/d) 0.3048 meter per day

gallon per minute (gal/min) 0.06309 liter per second

inch (in.) 25.4 millimeter

mile (mi) 1.609 kilometer

square foot (ft2) 0.0929 square meter

square foot per second (ft2/s) 0.0929 square meter per second

square mile (mi2) 2.59 square kilometer

ton 907.2 kilogram

Sea level: In this report, "sea level" refers to the National Geodetic vertical Datum of 1929 (NGVD of 1929, formerly called Sea-Level Datum of 1929), 

which is derived from a general adjustment of the first-order leveling networks of the United States and Canada.

Abbreviated water-quality unit used in this report: mg/L, milligram per liter
REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

AQUIFER SYSTEMS IN THE GREAT BASIN REGION OF 

NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT

By JAMES R. HARRILL and DAVID E. PRUDIC

ABSTRACT

The Great Basin Regional Aquifer-System Analysis (RASA) study 

area encompasses about 140,000 square miles in parts of Nevada, Utah, 

California, Oregon, Idaho, and Arizona. It contains numerous basins 

that collectively constitute a regional ground-water resource. Included 

are basins that have hydraulic continuity through permeable consolidated rock, basins that are linked by river systems, and basins that function as independent hydrologic systems. A special situation exists in 

western Utah and eastern Nevada where the basins are underlain and 

bounded by thick sequences of permeable carbonate rocks.

The study area is characterized by generally parallel, north- to northeast-trending mountain ranges separated by broad alluvial desert 

basins. The higher ranges in central and eastern Nevada and along the 

east and west margins of the region have crests more than 10,000 feet 

above sea level; elsewhere, altitudes of the mountains generally are less 

than 9,000 feet. Altitudes of valley floors range from below sea level in 

Death Valley to about 7,000 feet in central Nevada. A total of 260 hydrographic areas or subareas are presently recognized within the Great 

Basin region. Most of these hydrographic areas contain a basin-fill 

ground-water reservoir and include the topographically tributary drainage area in the adjacent mountains.

The Great Basin study area is separated into eastern and western 

areas on the basis of depositional facies of continental-shelf and continental-slope and -rise deposits. The western area includes the approximate western one-third of the Great Basin and is characterized by deepwater marine sedimentary rocks of Paleozoic and early Mesozoic age. 

The eastern two-thirds of the Great Basin is characterized by alternating 

sedimentary sequences dominated by clastic rocks, with minor amounts 

of limestone or dolomite, or by carbonate rocks with minor amounts of 

clastic rocks. The area dominated by carbonate rocks is known as the 

carbonate-rock province, a 100,000-square-mile area that lies mostly in 

eastern Nevada and western Utah. Generally, the overall thickness of 

carbonate-rock sequences exceeds that of clastic-rock sequences. The 

combined thicknesses of the carbonate- and clastic-rock sequences that 

compose the Paleozoic section range from about 5,000 feet to nearly 

30,000 feet. The dominant structural features are fault-block mountains 

and basins of Cenozoic age that formed as a result of extensional faulting.

Aquifer recharge is from precipitation, usually in the form of winter 

storms in the adjacent mountains. Recharge may occur either in the 

mountains (from melting snowpack) or along streams flowing over alluvial deposits adjacent to the mountains, depending on characteristics of 

the rock units that form the mountains. The timing and frequency of 

recharge also varies widely. Estimating natural recharge to the desert 

basins included in the RASA study area is difficult. The technical 

approach most commonly applied in Nevada and Utah is an empirical 

one developed in the 1940's and 1950's. In this study, a chloride-balance 

method was used to estimate natural ground-water recharge to 16 

basins in Nevada, and results compared favorably with existing empirical estimates.

Most ground-water discharge is by evapotranspiration, and most 

spring discharge ultimately is consumed by evapotranspiration. The 

principal areas of ground-water discharge are in topographically low 

parts of valleys where the water table is near the land surface. Estimates 

of ground-water evapotranspiration are not available for every basin in 

the study area. However, if the system is considered to be in a general 

state of dynamic equilibrium, then the total natural ground-water discharge is about equal to the recharge, which is about 3.8 million acre-feet 

per year for the entire study area.

Thirty-nine major flow systems were delineated. They range from 30 

to 18,000 square miles in area. Sixteen are single-basin systems, and the 

remainder are multibasin systems that may include as many as 34 

hydrographic areas or subareas. Except in the carbonate-rock province, 

large multibasin flow systems are generally coincident with major river 

systems. Large multibasin systems within the carbonate-rock province 

typically have little surface flow but may contain ground-water flow 

paths more than 100 miles long that traverse several basins. Discharge 

from these systems is typically from large springs. This discharge generally is consumed by evapotranspiration in the vicinity of the spring. An 

exception is the Muddy River springs that discharge into the Muddy 

River, which is a tributary of the Colorado River.

A three-dimensional finite-difference ground-water flow model was 

used to evaluate regional ground-water flow in the carbonate-rock province. The model simulated 45 shallow-flow regions in the upper model 

layer and 17 deep-flow subregions in the lower layer. The deep-flow 

subregions were further grouped into five deep-flow regions on the 

basis of areas having simulated water levels that generally decline 

toward one of five regional discharge areas. These are called the Death 

Valley, Colorado River, Bonneville, Railroad Valley, and upper Humboldt River regions.

Al
A2 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

Analysis of the model simulations has led to several conclusions: 

(1) Most ground-water flow is relatively shallow, moving from recharge 

areas in the mountains to discharge areas in adjacent valleys. (2) Interbasin movement of ground water to the larger regional springs is through 

thick, hydraulically continuous, permeable carbonate rock. (3) In some 

areas, consolidated rocks beneath the valleys and surrounding mountains are not highly transmissive; either not all carbonate rock is highly 

permeable or not all valleys and surrounding mountains are underlain 

by carbonate rock. (4) In some areas, carbonate rocks may be highly 

transmissive but separated from overlying aquifers by low-permeability 

rocks or deposits. (5) Deep flow discharges at the major downgradient 

terminal sinks only in relatively small quantities. Instead, deep flow discharges mainly to regional springs and areas of evapotranspiration 

upgradient from the sinks. (6) Simulated deep flow in the upper Humboldt River region is low in volume because most of the ground water 

discharging along the river is from local flow associated with the river.

Five basin-fill aquifers were selected as representative examples of 

the large range of conditions across in the study area. They are the Milford area in Utah and the Carson, Paradise, Smith Creek, and Stagecoach 

Valleys in Nevada. The Milford area represents a large basin-fill aquifer 

under sustained development; Carson Valley represents a basin-fill 

aquifer dominated by a through-flowing river; Paradise Valley represents a basin-fill reservoir having an upgradient part dominated by 

streams and an arid lower part; Smith Creek Valley represents a topographically closed, arid basin; and Stagecoach Valley represents a small, 

topographically closed basin that is partly drained by subsurface flow.

Results indicate that if pumping is located strategically with respect 

to areas of natural discharge, then a sustained-yield concept may be a 

viable management option. If pumping is not located strategically with 

respect to discharge or is highly concentrated, the sustained-yield concept may not be viable because localized drawdowns can become large 

before all natural discharge is captured. The location of pumping and 

the degree to which pumping is concentrated can be as significant as the 

overall pumping rate in determining response to pumping. Where 

streams and rivers are in hydraulic continuity with ground water, the 

location of pumping relative to these features is important in determining response to pumping.

Water in the principal aquifers of the Great Basin generally contains 

less than 1,000 milligrams of dissolved solids per liter, except in naturaldischarge and geothermal areas. Geochemical and hydrologic processes 

responsible for the major-ion chemistry and isotopic composition of 

water in aquifers throughout the Great Basin have been identified for 

representative examples of the two principal types of flow systems, a 

hydrologically closed basin-fill aquifer in west-central Nevada and a 

regional carbonate-rock aquifer in southern Nevada.

The main processes controlling geochemical evolution of ground 

water in the closed basin-fill aquifer of Smith Creek Valley are (1) dissolution of volcanic tuff and tuff-derived basin-fill deposits, (2) cation 

exchange of calcium and magnesium in the water for sodium in clay 

minerals, (3) weathering of plagioclase to montmorillonite, (4) precipitation of zeolite minerals, (5) concentration of dissolved constituents by 

evapotranspiration, (6) dissolution of chloride and sulfate evaporative 

salts, and (7) precipitation of calcite.

Major-ion chemical and isotopic compositions of water in the carbonate-rock aquifers of southern Nevada evolve because of (1) dissolution 

of minerals and soil-zone carbon dioxide gas, (2) precipitation or formation of minerals, (3) ion exchange, (4) mixing of chemically or isotopically different waters, and (5) geothermal heating. For instance, gypsum 

dissolves, and the dissolution of gypsum causes dolomite to dissolve 

and calcite to precipitate; calcium and magnesium are exchanged for 

sodium in clays; chalcedony precipitates; kaolinite forms; and, in the 

vicinity of some springs, carbon dioxide gas exsolves. Sodium and 

potassium probably are added by dissolution of zeolite minerals and of 

volcanic glass and minerals. Locally, calcium, sodium, sulfate, and chloride are added by dissolution of gypsum and halite.

INTRODUCTION

The study area for the Great Basin Regional AquiferSystem Analysis (RASA) encompasses about 140,000 mi2 

and includes most of Nevada and parts of Utah, California, Oregon, Idaho, and Arizona (fig. 1). This area contains numerous basins that collectively constitute a 

significant regional ground-water resource. Most of the 

basins share many common geologic and hydrologic 

characteristics that facilitate their study as a group. In 

addition to basins that function as independent hydrologic systems, this group includes contiguous basins that 

have hydraulic continuity through permeable masses of 

consolidated rock or that are linked by river systems. In 

parts of western Utah and eastern Nevada, structural 

basins are underlain and bounded by thick sequences of 

permeable carbonate rocks; this special situation results 

in complex flow systems that contain both basin-fill and 

carbonate-rock aquifers.

The Great Basin RASA study focuses on two important 

aquifer systems, one composed of basin-fill aquifers and 

the other of carbonate-rock aquifers. Most of the basins 

throughout the study area contain basin-fill aquifers, 

most of which physically (but not necessarily hydraulically) are separated by intervening mountain ranges composed of consolidated rock. The carbonate-rock aquifers 

are within the carbonate-rock province, a 100,000-mi2 area 

that is mostly in eastern Nevada and western Utah. This 

area is characterized by some degree of hydraulic continuity between basins through the carbonate-rock aquifers. Several large multibasin ground-water flow systems 

have been identified in the carbonate-rock province.

REGIONAL ANALYSIS OF AQUIFER SYSTEMS IN 

GREAT BASIN STUDY AREA

BACKGROUND

The Great Basin RASA study began in 1981 and most 

study components were completed in 1987. The Great 

Basin regional aquifer system was the 10th to be studied 

as part of the U.S. Geological Survey's (USGS) national 

RASA program. The Great Basin RASA study area was 

selected because it encompasses about 260 individual 

basins that collectively constitute a major regional water 

resource. The included basins represent a wide variety of 

hydrologic conditions, ranging from basins that function 

as isolated flow systems to basins that are hydraulically 

continuous with adjacent areas and form complex 

regional flow systems. Surface-water supplies are almost 

fully appropriated throughout the area, and future development will be supplied either by pumping ground water 

or by reallocating surface supplies.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A3

120° 118° 116° 114° 112°

42°

40°

38°

36°

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

EXPLANATION 

 Boundary of study area, Great Basin Regional Aquifer System

FIGURE 1. Location and general features of study area, Great Basin Regional Aquifer System. Ephemeral streams and lakes are shown by dashing.
A4 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

MAJOR OBJECTIVES

The main purpose of this study was to develop a 

regional base of information that would support effective 

future management of ground water in this area. This 

regional information includes a description of the present 

and predevelopment conditions of the ground-water flow 

system and an analysis of the changes that have led to the 

present conditions. Specific objectives were to improve 

understanding of the flow system (including sources and 

rates of recharge and discharge), of the hydraulic properties of aquifers and confining units, of the functioning of 

multibasin flow systems, and of the effects of man's past 

and present activities on the aquifer systems of the Great 

Basin.

APPROACH

The approach taken to meet the objectives of this study 

was strongly influenced by the diverse nature of groundwater flow systems and the large number of basins in the 

study area. Not all hydrologic characteristics can be 

described regionally; however, a detailed appraisal of 260 

individual hydrographic areas or subareas was not feasible. Consequently, the general approach was to identify 

the key components and critical properties of groundwater flow systems throughout the study area. These 

were studied in selected "type areas" that have conditions 

representative of the region. Information developed during these area evaluations has transfer value, and the final 

phase of this project involved developing a regional analysis that included the extrapolation of as much information as possible to the entire study area.

PURPOSE AND SCOPE OF PROFESSIONAL PAPERS 

1409-A THROUGH 1409-H

The Professional Paper 1409 series consists of eight 

reports that describe various aspects of the geology, 

hydrology, and geochemistry of aquifer systems in the 

Great Basin RASA study area. The main focus of these 

reports is the description of regional and local groundwater flow systems. Particular emphasis is placed on geologic factors that control regional ground-water flow and 

on the manner in which various types of systems respond 

to sustained pumping stresses over the long term.

In Professional Paper 1409-A (this report), we summarize the hydrogeologic framework, hydraulic properties 

of the aquifers, regional flow systems, effects of groundwater development, and geochemistry of the Great Basin 

study area. These topics are discussed in detail in Professional Papers 1409-B through 1409-H and in several of 

the additional reports prepared in support of this study

(see section "Other Reports Prepared For This Study"). 

This report includes considerable material incorporated 

directly (and, in places, verbatim) from many of the 

nearly 60 reports that are products of the Great Basin 

Regional Aquifer System Analysis (see "References 

Cited").

In Professional Paper 1409-B, Plume (1996) described 

the hydrogeologic framework of the Great Basin study 

area. The discussion includes geologic features that control ground-water flow within individual basins and geologic features that control regional ground-water flow.

In Professional Paper 1409-C, Thomas and others 

(1996) described the aqueous geochemistry of aquifer systems in the Great Basin study area.

In Professional Paper 1409-D, Prudic and others (1995) 

described the simulation of regional ground-water flow 

in parts of western Utah, eastern Nevada, and southwestern California that are underlain by permeable carbonaterock aquifers.

In Professional Paper 1409-E, Thomas, Carlton, and 

Hines (1989) described the hydrology of Smith Creek Valley, a hydrologically closed basin in Lander County (central Nevada). A ground-water flow model was used to 

simulate conditions prior to significant development and 

then to evaluate the response to selected developmental 

alternatives.

In Professional Paper 1409-F, Prudic and Herman 

(1996) described the hydrology of Paradise Valley in 

northwestern Nevada. Paradise Valley is a tributary area 

of the Humboldt River. The hydrologic regimen of the 

upper part of the basin is dominated by streamflow 

whereas the lower part of the basin is arid. A groundwater flow model was used to simulate conditions prior 

to significant development and then to evaluate 

responses to selected developmental scenarios.

In Professional Paper 1409-G, Mason (1998) described 

the hydrology of the Milford area, a large, heavily 

pumped basin in central Utah. A ground-water flow 

model was used to simulate conditions prior to significant 

pumping and then to evaluate responses to selected 

developmental scenarios.

In Professional Paper 1409-H, Harrill and Preissler 

(1994) described the hydrology of Stagecoach Valley, a 

small topographically closed basin in western Nevada 

that is partly drained by subsurface flow. A ground-water 

flow model was used to simulate conditions prior to significant pumping and then to evaluate responses to 

selected developmental scenarios.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A5

OTHER REPORTS PREPARED FOR THIS STUDY

During the Great Basin RASA study, companion 

reports were prepared on hydrologic data by Bunch and 

Harrill (1984) and Mason and others (1985); on hydrogeology by Gates (1984), Harrill and others (1984, 1992), 

Plume and Carlton (1988), and Harrill and Hines (1995); 

on water quality by Welch and Thomas (1984), Thomas, 

Welch, and Preissler (1985, 1989), Welch and Williams 

(1986a-d, 1987a-j), and Thomas, Carlton, and Hines 

(1989); on evapotranspiration by Carman (1985, 1989, 

1993) and Hines (1992); on recharge by Campana and 

Boone (1986), Schulke (1987), and Dettinger (1989b); on 

hydrologic applications of geophysics by Plume (1984; 

1985; 1988a, b), Schaefer and others (1984,1986), Robbins 

and others (1985), and Schaefer (1988); on regional 

hydrology by Mifflin and Harrill (1981), Harrill (1984), 

Thomas and others (1986), and Harrill and others (1988); 

and on ground-water flow modeling by Burbey and Prudic (1985), Carlton (1985), Carlton and Thomas (1987), 

Schaefer (1993), Carey (1994), Prudic and others (1995), 

Prudic and Wood (1995), and Carey and Prudic (1996). 

The course of the study followed the general outline presented in a preliminary planning document by Harrill 

and others (1983).

PREVIOUS STUDIES

Numerous studies have been made of various aspects 

of the hydrology and geology of the Great Basin. Most of 

these studies pertain to localized areas or specific topics 

and are too numerous to mention here. This discussion 

will refer primarily to those studies that include a 

regional-scale analysis or summary that provides information useful to an analysis of the hydrogeology of the 

whole region.

One of the first reasonably comprehensive discussions 

of the area's geology was by Nolan (1943). He summarized and in part interpreted the published information 

that was available through 1938 on the geology of those 

parts of Nevada, California, and Utah that were included 

in the Basin and Range Province. At that time much of the 

area had not been mapped in detail and much of the subsequent work during the 1950's and 1960's involved 

quadrangle mapping. By the early 1960's the areal mapping had progressed to the point that regional-scale compilations of the geology were possible. Stokes (1963) and 

Hintze (1963) compiled l:250,000-scale maps of northwestern and southwestern Utah, respectively. Jennings 

(1977) compiled a geologic map of the State of California 

at a scale of 1:750,000, and Stewart and Carlson (1978) 

compiled a geologic map of Nevada at a scale of 1:500,000. 

Hintze (1980) updated the Utah maps and compiled a 

geologic map of the State of Utah at a scale of 1:500,000.

These compilations contributed greatly to the analysis of 

the regional stratigraphy and structures. Langenheim and 

Larson (1973) compiled a correlation of Great Basin stratigraphic units, and when Stewart (1980) described the 

geology of Nevada, he included detailed summaries of 

the depositional and structural evolution of the Great 

Basin. Allmendinger and others (1983, 1987) produced 

deep seismic profiles across the Great Basin, and Wernicke (1985) emphasized the importance of listric and 

low-angle extensional faulting in the overall tectonic 

development of the Basin and Range Province.

Much geophysical work has been done in the Great 

Basin, and since the early 1970's much effort has been put 

into systematically compiling the information. Both the 

California Division of Mines and Geology and the 

Nevada Bureau of Mines and Geology have programs to 

compile Bouguer gravity data on USGS l:250,000-scale 

topographic quadrangles that cover the entire State. Cook 

and others (1975) compiled a simple Bouguer gravity 

anomaly map of Utah at a scale of 1:1,000,000. Peterson 

(1974) provided more-detailed coverage of parts of northwestern Utah. Aeromagnetic information also has been 

compiled on a regional scale. Hildenbrand and others 

(1983) compiled the available data to produce a digital 

colored magnetic-anomaly map of the Basin and Range 

Province. Much of the seismic data for the area has been 

compiled by private companies, but much of the information has been made available in the public domain by the 

Consortium for Continental Reflection Profiling, which 

surveyed a deep reflection profile across the Great Basin 

(Allmendinger and others, 1987).

Early investigators working in southern Nevada noted 

that large springs issued from areas with limited surficial 

drainage and postulated that subsurface interbasin flow 

was occurring. Mendenhall (1909, p. 13) suggested that 

many of the desert springs in southern Nevada were not 

dependent on rainfall in the region surrounding the 

springs but that the origin of the water was from distant 

mountains. Carpenter (1915, p. 19) noted that consolidated rock exposed in the mountains of southeastern 

Nevada generally makes the adjacent valleys closed to 

downward leakage by making the sides and bottoms of 

the valleys practically impervious. He did, however, state 

that several closed valleys higher in altitude than adjacent 

valleys lost water through fissures in the rocks because 

water levels in the higher valleys were far below land surface. Meinzer (1917, p. 150) reported that water from a 

valley near Tonopah, Nev, leaked through a mountain 

range into an adjacent valley. These are some of the earliest reports that discuss the possibility of interbasin flow of 

ground water in the study area.
A6 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

The first serious efforts to evaluate regional groundwater flow were in the late 1950's when the USGS began 

intensive studies on the Nevada Test Site and adjacent 

lands. These studies have continued to the present time 

and have developed much information pertaining to 

regional flow in southern Nevada. The general findings 

were summarized by Winograd (1962), Winograd and 

Eakin (1965), Blankennagel and Weir (1973), and Winograd and Thordarson (1975). The next major step to 

understanding the hydrology of the area on a regional 

scale was the initiation of a USGS program of reconnaissance-level studies using similar techniques designed to 

provide areal coverage of Nevada and most of western 

Utah. The program was initiated in Nevada and subsequently implemented in Utah. It resulted in the publication of 60 reconnaissance reports by the Nevada 

Department of Conservation and Natural Resources 

(including Eakin, 1960; 1961a, b; 1962a, b, c; 1963a, b, c; 

1964; Malmberg and Eakin, 1962; Sinclair, 1962a, b; 1963a, 

b, c, d; Cohen and Everett, 1963; Crosthwaite, 1963; Rush 

and Eakin, 1963; Walker and Eakin, 1963; Cohen, 1964; 

Eakin and others, 1964, 1967; Everett, 1964; Everett and 

Rush, 1964,1965,1966,1967; Rush, 1964; 1967; 1968b, c, d; 

1971; Rush and Kazmi, 1965; Huxel and others, 1966; 

Malmberg and Worts, 1966; Rush and Everett, 1966; Rush 

and Huxel, 1966; Worts and Malmberg, 1966; Rush and 

Glancy, 1967; Glancy, 1968a, b; 1971; Glancy and Rush, 

1968; Harrill, 1968,1969,1970,1971; Glancy and Van Denburgh, 1969; Huxel and Harris, 1969; Van Denburgh and 

Glancy, 1970; Rush and Katzer, 1973; Van Denburgh and 

others, 1973; Van Denburgh and Rush, 1974; and Glancy 

and Katzer, 1976) and 19 reconnaissance reports by the 

Utah Department of Natural Resources (including Bolke 

and Price, 1969,1972; Hood and Waddell, 1969; Hood and 

others, 1969; Hood, 1971a, b; Stephens and Hood, 1973; 

Stephens, 1974a, b; 1977; Price and Bolke, 1976; Bolke and 

Sumsion, 1978; Stephens and Sumsion, 1978; and Gates 

and Kruer, 1981). The information developed by these 

studies provided much of the material used in analyzing 

the hydrology on a regional scale.

Eakin (1966) described the White River flow system, a 

regional interbasin ground-water system. Mifflin (1968) 

evaluated flow systems throughout Nevada. He identified 136 systems and separated them into two groups on 

the basis of the presence or absence of interbasin flow. 

Mifflin's work was augmented by Scott and others (1971), 

who prepared a map summarizing information on interbasin flow for 252 areas in Nevada. Winograd and Friedman (1972) demonstrated that ratios of the chemical 

isotopes deuterium and hydrogen were useful tools for 

tracing regional ground-water flow in the Great Basin.

Gates and Kruer (1981) described areas thought to be 

associated with regional ground-water flow in western 

Utah. Bedinger, Gates, and Stark (1984) and Bedinger, 

Harrill, and Thomas (1984) presented maps showing 

ground-water units of the parts of Nevada and Utah that 

are in the Great Basin; they approximately defined the 

units on the basis of water-table divides or topographic 

divides.

HYDROLOGIC ENVIRONMENT

PHYSIOGRAPHY

The Great Basin RASA study area is characterized by 

generally parallel, north- to northeast-trending mountain 

ranges separated by broad alluvial desert basins. Mountain ranges commonly are 40 to 80 mi long and typically 

are spaced 5 to 15 mi apart. Their crests commonly are 

1,000 to 5,000 ft above the adjacent valley floors. The 

higher ranges, which are in central and eastern Nevada 

and along the east and west margins of the study area, 

have crests more than 10,000 ft above sea level; elsewhere, 

altitudes of the mountains generally are less than 9,000 ft.

Altitudes of the valley floors range from below sea level 

in Death Valley to about 7,000 ft in central Nevada; however, the altitudes of the floors of most valleys are 4,000 to 

6,000 ft. Typically, an intermediate slope separates the valley floor from the bordering mountain ranges. This slope, 

sometimes called the alluvial apron, is formed either by 

coalescing alluvial fans or by sedimentary materials 

thinly mantling eroded bedrock surfaces. Gradients of 

these slopes generally range from a few tens of feet to several hundreds of feet per mile.

DRAINAGE

The Basin and Range physiographic province (Fenneman and Johnson, 1946) is an area of about 200,000 mi2 of 

mostly internal drainages; it has few surface outlets to the 

ocean. The Great Basin is a section in the northern Basin 

and Range. The Great Basin study area as described in 

this report includes about 140,000 mi2, largely in Nevada 

and Utah but with smaller components in California, Oregon, Idaho, and Arizona. The study area generally conforms to the Great Basin region as defined by Stewart 

(1980, p. 7); however, it includes an area of southeastern 

Nevada that is tributary to the Colorado River and 

excludes some parts of the Great Basin that are in southeastern California and southern Oregon and the headwater areas of some of the principal drainages in the 

Sierra Nevada and the Wasatch Range. The principal rivers in the study area are shown in figure 1.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A7

HYDROGRAPHIC AREAS

A total of 260 hydrographic areas1 or subareas are recognized within the Great Basin region (fig. 2, table 1). 

These areas usually are the basic units used by State and 

local agencies for water-resources planning and management, and they commonly include only one topographic 

basin. Most areas contain a basin-fill ground-water reservoir and include the drainage area in the adjacent mountains. Generally the topographic and geologic features 

that constitute the geographic boundaries of the hydrographic areas and subareas correspond to hydrologic 

boundaries; consequently, boundaries of larger groundwater flow systems generally correspond to boundaries 

of either hydrographic areas or subareas.

CLIMATE

Although generally arid to semiarid, the climate of the 

study area is highly variable, owing to large variations in 

altitude, the wide range in latitude, and the presence of 

numerous mountain ranges. Mean annual precipitation 

in the valleys ranges from less than 5 in. to about 16 in. 

and in the mountains from about 16 in. to more than 60 in. 

Estimated annual precipitation over the entire region 

averages about 11 in. (Eakin and others, 1976, p. G3). Most 

of the precipitation occurs during the winter; mountain 

snowpack that melts and runs off in the spring and summer is a major component of the region's total water supply.

Mean annual temperature ranges from about 30°F in 

some high northern valleys to about 60°F in the extreme 

southern valleys. One of the more characteristic features 

is the wide range between daily maximum and minimum 

temperatures. The daily range exceeds 30°F in most valleys and exceeds 50°F in some valleys of western Nevada. 

Large variations in temperature also occur within short 

distances because of variations in altitude. The average 

length of the growing season in the principal agricultural 

areas of the region ranges from about 100 to 175 days; it 

exceeds 200 days in the extreme south but is less than 30 

days in some higher, northern mountain valleys.

Mean annual humidity ranges from about 30 to 40 percent over most of the region and is about 20 percent in the 

extreme south. During summer months daytime humidity values of less than 10 percent are common in many of 

the arid valleys. The low humidity, abundant sunshine, 

and light to moderate winds cause rapid evaporation.

1 Formal hydrographic areas in Nevada were delineated systematically by 

the U.S. Geological Survey and Nevada Division of Water Resources in the late 

1960's (Rush, 1968a; Cardinalli and others, 1968) for scientific and administrative 

purposes. The official hydrographic-area names, numbers, and geographic 

boundaries continue to be used in Geological Survey scientific reports and Division of Water Resources administrative activities.

Mean annual lake evaporation ranges from about 45 in. in 

the north to more than 90 in. in the extreme south (Kohler 

and others, 1959).

GROUND-WATER DEVELOPMENT

Most ground-water withdrawals in the Great Basin 

RASA study area are from wells drilled into the basin-fill 

deposits beneath the valley floors because most of the 

people settled in the valleys, ground water in many of the 

valleys is generally shallow, and the basin-fill deposits 

generally yield large quantities of water to wells. Ground 

water in the valleys is within a few feet to several tens of 

feet below land surface; water levels are generally deeper 

in mountain areas. Eakin and others (1976, p. 15) reported 

yields of as much as 8,600 gal/min from large-capacity 

wells in north-central Utah.

Prior to World War II, most of the ground-water withdrawals were from flowing wells drilled into basin-fill 

deposits. Areas of flowing wells were concentrated 

largely along the east side of the study area in valleys 

adjacent to the Wasatch Range, although several other 

valleys, including Las Vegas Valley, had flowing wells. 

Ground-water withdrawals were generally small and 

constant until after World War II, when more-efficient 

pumps and inexpensive energy greatly increased the 

amount of ground water withdrawn to irrigate crops and 

supply a rapidly increasing population. The total amount 

of ground water withdrawn in the study area during 1975 

was approximately 1.3 million acre-ft. Major areas of 

ground-water withdrawals during 1975 are shown in figure 3.

GEOLOGIC SETTING

DEPOSITIONAL ENVIRONMENTS

The Great Basin is separated into eastern and western 

areas (fig. 4) on the basis of the occurrence of depositional 

facies of continental-shelf and continental-slope and -rise 

deposits. The western area includes the approximate 

western one-third of the Great Basin and is characterized 

by marine sedimentary rocks (chert, shale, siltstone, sandstone, and subordinate limestone) and marine volcanic 

rocks of Paleozoic and early Mesozoic age. The eastern 

two-thirds of the Great Basin is characterized by alternating sedimentary sequences that are dominated either by 

clastic rocks (mostly sandstone, shale, and conglomerate) 

with minor amounts of carbonate rocks (limestone or 

dolomite) or by carbonate rocks (limestone and dolomite) 

with minor amounts of clastic rocks. In general in the eastern Great Basin, the overall thickness of carbonate rocks
A8 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

42°

40°

38°

36°

OREGON

/A A33cX I J -* ^- .* ^_ A ^ ^^.. i 

4 r 2 LT^ta\ ^33B ^ k W itfi,^--^: ^.-»

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 2. Hydrographic areas and subareas of Great Basin study area as listed in table 1. Also shown are major ground-water flow systems (tables 1 

and 4; fig. 15). Modified from Cardinalli and others (1968), Rush (1968a), and Harrill (1988).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A9

exceeds that of clastic rocks, especially in the Middle 

Cambrian to Lower Triassic parts of the stratigraphic section. Combined thickness of carbonate and clastic rocks 

ranges from about 5,000 ft to nearly 30,000 ft. The area of 

eastern and transitional depositional fades shown in figure 4 corresponds to the general area of the carbonaterock province as used in this report (Plume, 1996, p. B5).

Continental-shelf deposits were still being laid down in 

the western Great Basin at the beginning of the Mesozoic 

Era. By Middle Triassic time, however, the continental 

margin had shifted westward so that the eastern Great 

Basin was an area of continental deposition and the western Great Basin an area of marine deposition (shelf and 

slope). The continental margin of western North America 

again shifted westward in Middle Jurassic time, and what 

is now the Great Basin became an area of continental deposition. Continental sedimentary rocks, interbedded with 

volcanic rocks of similar age, continued to form in basins 

of uncertain size and distribution into the middle or late 

Tertiary.

The size and distribution of sedimentary basins began 

to change drastically as early as Oligocene time. This 

change was coincident with the onset of the extensional 

faulting that began to form the present-day mountain 

ranges and basins of the Great Basin. The clastic deposits 

that accumulated while mountains and basins formed 

collectively are called basin-fill deposits. They range in 

age from middle Miocene or earlier through Holocene 

and consist of unsorted to sorted clay, silt, sand, gravel, 

and boulders. Some of the early basins appear to have had 

little or no relation to present-day basins; however, by the 

late Pliocene, the present distribution of mountains and 

basins was established.

The oldest rocks in the Great Basin are metamorphic 

rocks (mostly gneiss and schist) and granitic rocks of Precambrian age, commonly called Precambrian crystalline 

basement. Crystalline basement has been inferred to 

extend as far west as central Nevada (Stewart, 1980, p. 9- 

11). A wide range of intrusive igneous rocks was 

emplaced during the Mesozoic and Cenozoic Eras. Outcrop areas of these rocks range in size from a few square

EXPLANATION

73B Hydrographic area or subarea Area shown by 

number only, subarea by number plus letter

 Boundary of study area, Great Basin Regional 

Aquifer System

Boundary of major flow system Dashed where 

uncertain

Boundary of hydrographic area or subarea

miles to more than 100 mi2. Interpretation of aeromagnetic data indicates that the subsurface extent of some 

intrusions is even larger.

The most recent period of volcanism began during the 

Eocene and has continued at differing intensities into the 

Pleistocene and possibly Holocene. Volcanic rocks can be 

found in nearly every mountain range of the Great Basin. 

Volcanic rocks also underlie and are interbedded with 

basin-fill deposits in much of the Great Basin.

STRUCTURAL FEATURES

During parts of the Paleozoic, Mesozoic, and possibly 

early Cenozoic Eras, the Great Basin was undergoing tectonic compression, and since the middle to late Tertiary, it 

has been undergoing tectonic extension. The dominant 

tectonic events of Paleozoic and early Mesozoic time were 

the Late Devonian and Early Mississippian Antler orogeny and the Late Permian and Early Triassic Sonoma 

orogeny. The major structural features that resulted from 

these two orogenies are the Roberts Mountains thrust 

(Antler orogeny) and the Golconda thrust (Sonoma orogeny) (fig. 5). The dominant tectonic event of Mesozoic age 

was the Sevier orogeny, which resulted in compression of 

the Earth's crust along a belt that extends from southern 

Idaho through central and western Utah, southern 

Nevada, and southeastern California. In the vicinity of 

Salt Lake City, as many as six individual thrust plates are 

recognized, and in the southern Great Basin, the orogenic 

belt is composed of four major thrust plates.

A structural feature ot the Great Basin that may be 

related to more than one period of deformation is the 

Ruby Mountains metamorphic core complex (fig. 8). Two 

metamorphic core complexes are recognized within the 

Great Basin. Another is located along the margin of the 

Great Basin in northwestern Utah and south-central 

Idaho. The complexes are characterized by a ductilely 

deformed metamorphic-plutonic basement overlain by 

an unmetamorphosed terrane that is brittlely deformed 

along low-angle extensional faults. These two zones are 

separated by a surface of dislocation called a decollement 

or detachment that apparently is characteristic of all core 

complexes.

The dominant structural features of Cenozoic age in the 

Great Basin are the fault-block mountains and basins that 

formed as a result of extensional faulting. High-angle normal faults initially were perceived as the mechanism by 

which mountains and basins formed. Currently, however,
A10 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 1. Hydrographic areas and flow systems within study area, Great Basin Regional Aquifer System

[Numbers match those that are used to label areas in figure 2; major flow systems are shown in all-capital letters]]

Hydrographicarea or -subarea 

number

2

3

4

7

8

9

12

15

16

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

Name

CONTINENTAL LAKE SYSTEM

Continental Lake Valley

Gridley Lake Valley

VIRGIN VALLEY

SWAN LAKE VALLEY

LONG VALLEY SYSTEM

Massacre Lake Valley

Long Valley

Mosquito Valley

Boulder Valley

DUCK LAKE VALLEY

BLACK ROCK DESERT SYSTEM

Dry Valley

Sano Valley

Smoke Creek Desert

San Emidio Desert

Granite Basin

Hualapai Flat

High Rock Lake Valley

Mud Meadow

Summit Lake Valley

Black Rock Desert

Pine Forest Valley

Kings River Valley

A. Rio King Subarea

B. Sod House Subarea

Desert Valley

Silver State Valley

Quinn River Valley

A. Orovada Subarea

B. McDermitt Subarea

C. Oregon Canyon Subarea

HUMBOLDT SYSTEM

Marys River Area

Starr Valley Area

North Fork Area

Lamoille Valley

South Fork Area

Huntington Valley

Dixie Creek-Tenmile Creek Area

Elko Segment

Susie Creek Area

Maggie Creek Area

Marys Creek Area

Pine Valley

Crescent Valley

Carico Lake Valley

Upper Reese River Valley

Antelope Valley

Middle Reese River Valley

Lower Reese River Valley

Whirlwind Valley

Boulder Flat

Rock Creek Valley

Willow Creek Valley

Clovers Area

Pumpernickel Valley

Kelly Creek Area

Little Humboldt Valley

Hardscrabble Area

Paradise Valley

Winnemucca Segment

Grass Valley

Imlay Area

Hydrographicarea or -subarea 

number 

Continued

73

74

131

129

78

79

80

81

82

83

84

85

86

87

88

89

92

93

100

75

76

77

101

102

103

104

105

106

107

108

109

110

121

124

125

126

127

128

Name Continued

HUMBOLDT SYSTEM Continued

Lovelock Valley

A. Oreana Subarea

B. Upper and Lower Valley Areas

White Plains

BUFFALO VALLEY

BUENA VISTA VALLEY

GRANITE SPRINGS SYSTEM

Granite Springs Valley

Kumiva Valley

WINNEMUCCA LAKE VALLEY

TRUCKEE SYSTEM

Pyramid Lake Valley

Dodge Flat

Tracy Segment

Warm Springs Valley

Spanish Springs Valley

Sun Valley

Truckee Meadows

Pleasant Valley

Washoe Valley

LEMMON VALLEY

Lernmon Valley

A. Western Part

B. Eastern Part

Antelope Valley

COLD SPRING VALLEY

FERNLEY SINK SYSTEM

Bradys Hot Springs Area

Fernley Area

Fireball Valley

CARSON SYSTEM

Carson Desert

A. Packard Valley

B. Lahontan Valley

Churchill Valley

Dayton Valley

A. Carson Plains

B. Stagecoach Valley

Eagle Valley

Carson Valley

WALKER SYSTEM

Antelope Valley

Smith Valley

Mason Valley

East Walker Area

Walker Lake Valley

A. Schurz Subarea

B. Lake Subarea

C. Whiskey Flat-Hawthorne Subarea

Soda Spring Valley

B. Western Part

C. Central Part

DIXIE VALLEY SYSTEM

Fairview Valley

Stingaree Valley

Cowkick Valley

Eastgate Valley Area

Dixie Valley
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT All

TABLE 1. Hydrographic areas and flow systems within study area, Great Basin Regional Aquifer System Continued

[Numbers match those that are used to label areas in figure 2; major flow systems are shown in all-capital letter]

Hydrographicarea or -subarea 

number 

Continued

130

132

133

134

123

122

136

113

114

117

118

119

120

121

135

137

141

142

143

149

138

137

139 

140

151 

152 

153

144 

145

146 

147

148

157 

158

159

160

161 

162 

168 

169

173

211

225

226

227

Name Continued

DIXIE VALLEY SYSTEM Continued

Pleasant Valley

Jersey Valley

EDWARDS CREEK VALLEY

SMITH CREEK VALLEY

RAWHIDE FLATS

GABBS VALLEY

MONTE CRISTO VALLEY

SOUTH-CENTRAL MARSHES

Huntoon Valley

Teels Marsh Valley

Fish Lake Valley

Columbus Salt Marsh Valley

Rhodes Salt Marsh Valley

Garfield Flat

Soda Spring Valley

A. Eastern Part

lone Valley

Big Smoky Valley

A. Tonopah Flat

Ralston Valley

Alkali Spring Valley

Clayton Valley

Stone Cabin Valley

GRASS VALLEY

BIG SMOKY VALLEY 

B. Northern Part

DIAMOND VALLEY SYSTEM

Kobeh Valley 

Monitor Valley

A. Northern Part

B. Southern Part 

Antelope Valley (Eureka and Nye) 

Stevens Basin 

Diamond Valley

DEATH VALLEY SYSTEM 

Lida Valley 

Stonewall Flat

Sarcobatus Flat 

Gold Flat

Cactus Flat

Kawich Valley 

Emigrant Valley 

A. Groom Lake Valley 

B. Papoose Lake Valley 

Yucca Flat

Frenchman Flat

Indian Springs Valley 

Pahrump Valley 

Three Lakes Valley (Northern Part) 

Tikapoo Valley 

A. Northern part 

B. Southern Part

Railroad Valley 

A. Southern Part

Three Lakes Valley (Southern Part) 

Mercury Valley

Rock Valley

Fortymile Canyon 

A. Jackass Flats

B. Buckboard Mesa

Hydrographicarea or -subarea 

number 

Continued

228

229

230

240

241

242

243

244

245

154

155

150

155

156

173

170

177

188

176 

178

164

165 

166 

167 

171

172

174 

175

180 

181

182

183 

198 

199 

200 

201

202

203 

204 

205 

206 

207 

208

209 

210

212 

215

216

217 

218

219

Name Continued

DEATH VALLEY SYSTEM Continued

Oasis Valley

Crater Flat

Amargosa Desert

Chicago Valley

California Valley

Lower Amargosa Valley

Death Valley

Valjean Valley

Shadow Valley

NEWARK VALLEY SYSTEM

Newark Valley

Little Smoky Valley

A. Northern Part

B. Central Part

RAILROAD VALLEY SYSTEM

Little Fish Lake Valley

Little Smoky Valley

C. Southern Part

Hot Creek Valley

Railroad Valley

B. Northern Part

PENOYER VALLEY

INDEPENDENCE VALLEY SYSTEM

Clover Valley

Independence Valley (Pequop Valley)

RUBY VALLEY SYSTEM

Ruby Valley 

Butte Valley 

A. Northern Part

COLORADO SYSTEM

Ivanpah Valley 

A. Southern Part

B. Northern Part

Jean Lake Valley 

Hidden Valley (South) 

Eldorado Valley 

Coal Valley

Garden Valley 

Jakes Valley 

Long Valley

Cave Valley 

Dry Lake Valley

Delamar Valley

Lake Valley 

Dry Valley 

Rose Valley 

Eagle Valley 

Spring Valley

Patterson Valley

Panaca Valley 

Clover Valley 

Lower Meadow Valley Wash 

Kane Springs Valley 

White River Valley 

Pahroc Valley

Pahranagat Valley 

Coyote Spring Valley

Las Vegas Valley 

Black Mountains Area

Garnet Valley

Hidden Valley (North) 

California Wash

Muddy River Springs Area
A12 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 1. Hydrographic areas and flow systems within study area, Great Basin Regional Aquifer System Continued

[Numbers match those that are used to label areas in figure 2; major flow systems are shown in all-capital letters]

Hydrographicarea or -subarea

number 

Continued

Name Continued

Hydrographicarea or -subarea

number 

Continued

Name Continued

220

221

222

178

179

187

163

251

252

253

254

255

256

257

258

259

260

261

184

185

186

189

191

COLORADO SYSTEM Continued 

Lower Moapa Valley 

Tule Desert 

Virgin River Valley

GOSHUTE VALLEY SYSTEM 

Butte Valley

B. Southern Part 

Steptoe Valley 

Goshute Valley

MESQUITE VALLEY

GREAT SALT LAKE DESERT SYSTEM 

Grouse Creek Valley 

Pilot Valley 

Deep Creek Valley 

Snake Valley 

Pine Valley 

Wah Wah Valley 

Tule Valley 

Fish Springs Flat

Dugway-Government Creek Valley 

Park Valley

A. West Park Valley 

Great Salt Lake Desert

A. West Part 

Spring Valley 

Tippett Valley 

Antelope Valley

A. Southern Part

B. Northern Valley 

Thousand Springs Valley

A. Herrell Siding-Brush Creek Area

B. Toano-Rock Spring

C. Rocky Butte Area

D. Montello-Crittenden Creek Area 

Pilot Creek Valley

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

GREAT SALT LAKE SYSTEM

Park Valley

B. East Park Valley

Great Salt Lake Desert 

B. East Part

Tooele Valley

Rush Valley

Cedar Valley

Utah Valley Area

A. Goshen Valley

B. Southern Utah Valley

C. Northern Utah Valley

Northern Juab Valley

Salt Lake Valley

East Shore Area

West Shore Area

Skull Valley

Sink Valley

Cache Valley

Malad-Lower Bear River Area

Pocatello Valley

Blue Creek Valley

Hansel and Northern Rozel Flat

Promontory Mountains Area

Curlew Valley

Great Salt Lake

SEVIER LAKE SYSTEM 

Beryl-Enterprise Area 

Parowan Valley 

Cedar City Valley 

Beaver Valley 

Milford Area 

Leamington Canyon 

Pavant Valley 

Sevier Desert

three types of normal faults are recognized: (1) high-angle 

normal faults, (2) listric normal faults, which curve and 

flatten with depth, and (3) low-angle normal faults that 

generally have placed younger rocks over older ones and 

commonly are called detachments. These three types of 

faults have been found in all parts of the Great Basin.

The Walker Lane belt, which is mostly in western 

Nevada, is an area of irregular topographic trends that 

contrast with the more regular north-northeast trends 

observed in the rest of the Great Basin. The belt is a structurally complex zone characterized by several structural 

blocks, each with styles of deformation and structural features that do not extend to adjacent blocks (Stewart, 1988, 

p. 686).

EXPLANATION

Estimated ground-water withdrawals for 1975, 

by hydrographic area or subarea, in acre-feet

999 or less

1.000 to 4,999 

5,000 to 19,999 

20,000 to 79,999 

80,000 or greater

 Boundary of study area, Great Basin Regional 

Aquifer System

 Boundary of hydrographic area or subarea (fig. 2)
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A13

120 118° 116' 114- 112°

OREGON

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 3. Estimated ground-water withdrawals for 1975 in hydrographic areas and subareas of Great Basin study area (fig. 2, table 1). Estimates of 

ground-water withdrawals for Utah from Sumsion and others (1976); estimates for Nevada from Bedinger, Harrill, and Thomas (1984).
A14 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

42°

40°

38° 

36° 

-'_>. \ I

\ . x- L~__

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 4. Occurrence of depositional facies of early Mesozoic and older rocks in Great Basin study area. Modified after Plume (1996, p. B4).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A15

HYDROGEOLOGY

The consolidated rocks and unconsolidated to semiconsolidated deposits that underlie the Great Basin were 

grouped into several hydrogeologic units that either store 

and transmit ground water in regional aquifer systems or 

impede the movement of ground water (Plume, 1996). 

Hydrogeologic units in the western Great Basin are (1) 

sedimentary and igneous rocks of late Precambrian to 

Quaternary age, (2) older basin-fill deposits (Miocene and 

Pliocene), and (3) younger basin-fill deposits (Pliocene to 

Holocene). Hydrogeologic units in the eastern Great 

Basin are (1) metamorphic, igneous, and sedimentary 

rocks of Precambrian and Early Cambrian age; (2) carbonate and clastic sedimentary rocks of Middle Cambrian to 

Early Triassic age, (3) sedimentary and igneous rocks of 

Middle Triassic to Quaternary age, (4) older basin-fill 

deposits (Miocene and Pliocene), and (5) younger basinfill deposits (Pliocene to Holocene). The two main aquifer 

systems recognized in the Great Basin consist of the basinfill units (basin-fill aquifers) and the carbonate and clastic 

sedimentary rocks of Middle Cambrian to Early Triassic 

age (carbonate-rock aquifers). The other units mostly 

impede ground-water flow, although several exceptions 

to this were described by Plume (1996). The distribution 

of the basin-fill aquifers, the carbonate-rock aquifers, and 

the rocks that impede ground-water flow is shown in figure 6. The relation of these units to Plume's (1996) hydrogeologic units is presented in table 2.

CARBONATE-ROCK AQUIFERS

The eastern Great Basin is underlain by thick sections of 

marine sedimentary rocks that can be separated broadly 

into two parts: an upper part of Middle Cambrian to 

Lower Triassic carbonate rocks with minor amounts of 

clastic sedimentary rocks and a lower part of upper Precambrian and Lower Cambrian clastic sedimentary rocks. 

The carbonate and clastic sedimentary rocks constitute an 

extensive hydrogeologic unit that underlies the entire 

eastern two-thirds of the Great Basin (fig. 6). The western 

limit of this unit, as adopted for this report, is the westernEXPLANATION 

Western depositional facies

Eastern and transitional depositional facies 

Corresponds to carbonate-rock province

Boundary of study area, Great Basin Regional 

Aquifer System

most extent of Stewart and Carlson's (1978) carbonate 

(eastern) assemblage. General lithology of this hydrogeologic unit and specific formations included in the unit 

were summarized by Plume (1996, 34-40). The overall 

stratigraphic thickness of the unit ranges from about 5,000 

ft to nearly 30,000 ft. However, stratigraphic thickness 

does not necessarily indicate the depth to which ground 

water circulates, because structural deformation of the 

section can result in apparent thicknesses that differ 

markedly from true stratigraphic thickness and because 

the carbonate rocks may not be permeable throughout 

their entire stratigraphic thickness.

The carbonate-rock aquifers as defined by Dettinger 

(1989a, p. 5-7) are composed mostly of the carbonate-rock 

sequence just described. The carbonate-rock aquifer system generally is bounded laterally by the limits of the carbonate-rock province shown in figure 5. The aquifer 

system is underlain by metamorphic, igneous, and sedimentary rocks of Precambrian and Early Cambrian age. 

The carbonate-rock aquifers include what Winograd and 

Thordarson (1975, p. 10-11) called the upper and lower 

carbonate aquifers and upper clastic aquitard in the 

south-central Great Basin and what Plume and Carlton 

(1988) described as the upper and lower parts of the carbonate-rock aquifer and intervening clastic sedimentary 

rocks in the eastern Great Basin.

Fractures and joints that may have been widened by 

solution are the principal openings that store and transmit ground water in the carbonate-rock aquifers. Three 

types of porosity have been recognized in carbonate rocks 

in south-central Nevada intercrystalline, vug, and fracture, the third being most important to the movement and 

storage of ground water (Winograd and Thordarson, 

1975, p. 14^40). Typical fracture porosities determined 

from laboratory measurement of core samples range from 

0 to 1 percent and average 0.1 percent, whereas fracture 

porosities estimated from geophysical logs range from 0 

to as much as 28 percent, although the upper limit commonly is closer to 10 percent (Winograd and Thordarson, 

1975, p. 18-19). Berger (1992, p. 18) determined a mean 

total porosity of 4.7 percent from analysis of geophysical 

logs of five test wells in carbonate-rock aquifers in and 

near Coyote Spring Valley in southern Nevada. An effective porosity of 9 percent was determined for Paleozoic 

dolomite at the Nevada Test Site of southern Nevada 

using measurements of Earth tides and barometric fluctuations (Galloway, 1986). Values of porosity recorded on 

American Stratigraphic Company (AMSTRAT) logs of 

petroleum-exploration wells drilled in the eastern Great 

Basin ranged from 0 to more than 20 percent, although the 

upper limit of the range commonly is less than 10 percent 

(Plume, 1996, p. 41-58).
A16 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

42°

40° 

38°

36°

..*

'J Btfarson 

Lake - , . / City 

Tahoe

Carson

Valley

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 5. Selected geologic features of Great Basin study area (Stewart and Carlson, 1978; Hintze, 1980; and Stewart, 1980, p. 10-64). DF, Death

Valley-Furnace Creek fault zone; LV, Las Vegas shear zone.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A17

Transmissivity of carbonate-rock aquifers has been 

determined at several sites in the eastern Great Basin. Values of hydraulic conductivity estimated from 23 aquifer 

tests (Winograd and Thordarson, 1975, p. 22-23; Bunch 

and Harrill, 1984, p. 119; Dettinger and others, 1995) distributed over much of the Great Basin study area ranged 

from 0.005 to 900 ft/d and had a mean of 80 ft/d and a 

median of 0.8 ft/d (Plume, 1996, p. B13). The range of values indicates that these aquifers are very heterogeneous. 

AMSTRAT logs analyzed by Plume (1996) indicate that 

zones of high porosity commonly are less than 100 ft thick 

and are separated by hundreds to thousands of feet of 

low-porosity rock. One possible interpretation is that 

zones of low porosity identified on the AMSTRAT logs 

are characterized by the types of microscopic porosity 

seen in thin sections and presumably by low values of 

hydraulic conductivity. Another is that zones of high 

porosity and hydraulic conductivity are restricted to relatively narrow fault or fracture zones among much wider 

zones of low porosity.

In addition to the aquifer tests at wells, transmissivity 

has been estimated for the carbonate-rock aquifers by 

using Darcy's law. Using values of underflow estimated 

from water budgets, estimated aquifer widths, and 

hydraulic gradients computed from ground-water-level 

measurements, Eakin (1966, p. 266) computed values of 

transmissivity of 30,000 and 20,000 ft2 /d for the carbonate-rock aquifer at the north and south ends of White 

River Valley (Nevada), respectively, and 30,000 ft2 /d for 

the middle part of Coyote Spring Valley (also in Nevada). 

Using a similar approach and aeromagnetic data, Plume 

(1988b) revised the estimate of regional transmissivity for 

the carbonate-rock aquifer at the north end of White River 

Valley to 20,000 ft2 /d.

EXPLANATION

Carbonate-rock province Shows approximate 

extent of Middle Cambrian to Lower Triassic 

carbonate rocks and associated clastic rocks. 

West boundary (modified from Plume, 1996, 

p. B4) corresponds to easternmost extent of 

Paleozoic transitional-assemblage sedimentary 

rocks as defined by Stewart and Carlson 

(1978) and by Stewart (1980, p. 20).

Boundary of study area, Great Basin Regional 

Aquifer System

Strike-slip fault Arrows indicate relative 

movement

Thrust fault Teeth on upper plate

BASIN-FILL AQUIFERS

Each hydrographic area in the region is underlain by a 

structural basin partly filled with clastic material eroded 

from the adjacent mountains. These deposits form basinfill aquifers that are bounded by the consolidated rocks of 

the structural basin. Some are connected hydraulically to 

a similar aquifer in an adjacent hydrographic area by 

basin-fill deposits or permeable consolidated rocks. In the 

eastern Great Basin, most are connected hydraulically to 

adjacent or underlying carbonate-rock aquifers.

The geometry of a basin and the composition of the 

basin-fill deposits essentially define its hydrogeologic 

framework. Basin-fill deposits typically consist of an 

older unit of upper Miocene and lower Pliocene deposits 

and a younger unit of upper Pliocene to Holocene deposits (Plume, 1996). Younger basin fill consists of unconsolidated to semiconsolidated deposits of sand, silt, gravel, 

and clay and make up the uppermost part of the fill in 

most basins. The sand and gravel deposits yield water 

readily to wells and are the aquifers most commonly 

developed. The subsurface extent of the younger basin fill 

is uncertain because it is difficult to distinguish from the 

older basin fill solely on the basis of well logs. In addition, 

the distinction between older and younger basin fill has 

not always been emphasized in geologic studies and the 

relations of the units are not always easy to understand 

(Stewart, 1980, p. 95). Consequently, hereafter in this 

report the younger and older basin-fill deposits collectively are called basin-fill deposits. Gates (1984, p. 243) 

reported that in most places in northwestern Utah probably only the upper 500 to 1,500 ft of the basin fill is permeable and contains potable water.

Hydraulic conductivities of basin-fill deposits differ laterally and vertically owing to changes in composition of 

the deposits. The range of conductivity values for aquifertest results of 17 wells is 0.02 to 140 ft/d as reported by 

Bunch and Harrill (1984, p. 115-118). That range is probably reasonable for basin-fill deposits that have not been 

reworked by a perennial stream. The mean and median 

values for all 17 wells are 78 and 83 ft/d, respectively. 

Ranges of hydraulic conductivity were compiled for 

broad physiographic settings by Plume (1996, p. B16- 

B17), who concluded that values of hydraulic conductivity should be larger toward basin margins and smaller, 

and within broader ranges, near the basin axis. Similar 

trends in composition and in hydraulic-conductivity values apply to basins with a perennial or nearly perennial 

stream. One exception is where those deposits of past and 

present stream flood plains include reworked materials 

along the axis of a basin. These materials can be much 

more productive aquifers than comparable deposits that 

have not been reworked by a stream.
A18 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

42 A »<*. «*» _ ^ 

"* r\_[ ^ i

^ _»^. »«« ,_. ^^^ - , fL... _ . niiii

 >^

38° 

36° 

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

Geology modified from Plume and Carlton (1988)

FIGURE 6. Hydrogeologic units of Great Basin study area.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A19

Geometries of structural basins range from simple to 

complex, depending on the tectonic history of the basins. 

Thickness of fill generally ranges from 0 ft at basin margins to greater than 10,000 ft in a few areas; the average 

thickness is at least several thousand feet. Idealized sections of six basins selected to represent the more common 

basin geometries in the Great Basin are shown in figure 7. 

Two broad types of basin geometry are shown: structural 

basins that are relatively symmetrical with respect to their 

topographic basins and structural basins that are asymmetrical. Seismic-reflection data for other valleys in 

Nevada and western Utah (Anderson and others, 1983) 

indicate that basin geometries can be more complex than 

the ones shown in figure 7. Nonetheless, the basic shapes 

defined by Anderson and others (1983, p. 1067) generally 

can be categorized as either relatively symmetrical or 

asymmetrical.

VOLCANIC-ROCK AQUIFERS

Except for carbonate-rock aquifers and basin-fill aquifers, other hydrogeologic units in the Great Basin generally confine the movement of ground water. The most 

notable exceptions are some Cenozoic volcanic-rock units 

in parts of the Great Basin. Volcanic rocks have been recognized as aquifers in relatively few areas in spite of their 

prevalence in the Great Basin. These areas include the Fallon area, western Nevada (Glancy, 1986); the Nevada Test 

Site, southern Nevada (Winograd and Thordarson, 1975);

EXPLANATION

I I Basin fill Mixed alluvial, colluvial, and lacustrine 

basin-fill deposits; some interbedded volcanic 

deposits. Most water pumped by wells is derived 

from deposits of gravel or sand or both. Forms 

basin-fill aquifers

I j Carbonate rocks Sequences of permeable carbonate and clastic sedimentary rocks. Highest 

yielding aquifers are in areas of fractured carbonate rocks, where some fractures may have 

been enlarged by dissolution. Form carbonaterock aquifers

[ [|xj Noncarbonate consolidated rocks Fine-grained 

clastic rocks, metamorphic rocks, intrusive rocks, 

and most volcanic rocks. Generally function as 

relative barrier to ground-water flow. Stipple 

' indicates very fractured volcanic rocks (some 

basalts and other flow rocks and some welded 

tuffs) that form highly permeable aquifers

 Boundary of study area, Great Basin Regional 

Aquifer System

part of central Nevada (Fiero, 1968); part of southeastern 

Nevada (Emme, 1986); and the Pavant Valley, western 

Utah (Mower, 1965). Basalt flows enclosed by basin-fill 

deposits form important aquifers in the Fallen area and in 

Pavant Valley. Lava flows and welded tuffs form important aquifers at the Nevada Test Site, whereas ash-flow 

and air-fall tuffs have low permeability and generally act 

as confining units. In other parts of the study area, such as 

Railroad Valley, most volcanic rocks have low permeability and do not readily transmit ground water.

BARRIERS TO REGIONAL GROUND-WATER FLOW

Ground-water flow is affected by a wide variety of rock 

units that do not readily transmit ground water. These 

barriers confine ground-water flow in both vertical and 

horizontal directions. In the carbonate-rock aquifers, they 

form parts of boundaries between flow regions (as 

defined by Prudic and others, 1995) and form zones of 

low permeability, and in the western Great Basin and to a 

lesser extent the eastern Great Basin, they bound the 

structural basins that contain basin-fill aquifers. The rocks 

that form these barriers and low-permeability zones are 

included in "noncarbonate consolidated rocks" in figure 6.

The importance of any of the rock types as barriers to 

flow is not fully understood because their subsurface 

extents are not always indicated by study of outcrops or 

geologic maps. Precambrian crystalline basement and 

Jurassic to Tertiary granitic rocks contain magnetic minerals, and the magnetization contrasts between these and 

adjacent, less magnetic rocks are generally sufficient that 

the subsurface geometry of the more magnetic bodies 

(basement rocks and younger granitic rocks) can be 

approximated by analyzing aeromagnetic data. Plume 

(1996) used aeromagnetic data to evaluate the occurrence 

and subsurface distribution of these bodies. Outcrop 

areas of rocks that are potential barriers to ground-water 

flow and the subsurface extent of magnetic-source bodies 

in the eastern Great Basin are shown in figure 8. Potential 

barriers to regional ground-water flow include rocks of 

Precambrian and Early Cambrian age clastic sedimentary rocks, crystalline basement, and the metamorphic 

core complexes in the Snake Range and Rub\ Mountains 

in Nevada as well as granitic rocks of Jurassic to Tertiary 

age. The magnetic-source bodies shown in figure 8 probably consist of either Precambrian crystalline basement or 

Jurassic to Tertiary granitic rocks. They are considered to 

be subsurface barriers to deep, regional ground-water 

flow.
A20 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 2. Aquifers and confining units in Great Basin study area

[Modified from Plume (1996, p. B34-B40)]

Aquifer or 

confining unit Hydrogeologic unit Generalized geology Water-bearing characteristics

Basin-fill 

aquifers.

Carbonate-rock 

aquifers.

Volcanic-rock 

aquifers.

Confining units 

and relatively 

impermeable 

barriers.

Younger basin-fill deposits of late 

Pliocene to Holocene age and 

older basin-fill deposits of middle 

Miocene to early Pliocene age.

Carbonate and clastic sedimentary 

rocks of Middle Cambrian to Early 

Triassic age in eastern Great Basin.

Subunit of sedimentary and igneous 

rocks of late Precambrian to Quaternary age in western Great Basin 

and of sedimentary and igneous 

rocks of Middle Triassic to Quaternary age in eastern Great Basin.

Sedimentary and igneous rocks of 

late Precambrian to Quaternary 

age in western Great Basin; sedimentary and igneous rocks of 

Middle Triassic to Quaternary 

age and metamorphic, igneous, 

and sedimentary rocks of late 

Precambrian and Early Cambrian 

age in eastern Great Basin.

Younger basin-fill deposits consist of unconsolidated to semiconsolidated deposits in alluvial 

fans and pediments (unsorted to poorly sorted 

silt, sand, gravel, and boulders), in valley lowlands and playas (poorly sorted clay, silt, sand, 

and gravel), and in stream flood plains (moderately sorted to well-sorted beds of silt and clay 

or sand and gravel). Older basin-fill deposits 

consist of semiconsolidated to consolidated 

fanglomerate, sandstone, siltstone, mudstone, 

limestone, and interbedded volcanic rocks.

Interbedded limestone, dolomite, sandstone, and 

shale. Contains some beds of conglomerate 

and gypsum.

Flows and flow breccias, which range in composition from basalt to rhyolite, and silicic 

welded tuffs. Where these rocks are highly 

fractured, they form aquifers instead of confining units.

Fine-grained sedimentary rocks, most volcanic 

rocks, intrusive rocks, metamorphic rocks, and 

older crystalline basement.

Younger and older basin-fill deposits, collectively 

referred to as basin fill, form basin-fill aquifers and 

yield much of the ground water used in Great Basin. 

Estimates of hydraulic conductivity for basin-fill 

deposits excluding flood-plain deposits ranged 

from 0.02 to 140 feet per day and averaged 78 feet 

per day. Hydraulic conductivities of flood-plain 

deposits were estimated to range from 16 to 1,100 

feet per day and averaged 130 feet per day.

Unit forms carbonate-rock aquifers in eastern Great 

Basin. Ground water is transmitted mostly along 

joints and fractures. Estimates of hydraulic conductivity range from 0.0005 to 900 feet per day; higher 

values correspond to fault or fracture zones and 

lower values to relatively unfractured rock.

Localized conditions of high permeability are characteristic of this unit. A basalt aquifer interbedded 

with younger basin-fill deposits at Fallen, Nev., has 

hydraulic conductivities estimated to range from 

130 to 3,100 feet per day. Basalts interbedded with 

basin-fill deposits in Pavant Valley, Utah, have 

estimated hydraulic conductivities that range from 

370 to 46,000 feet per day. Lava flows and welded 

tuffs at Nevada Test Site (south-central Nevada) 

have hydraulic conductivities that range from 1.5 to 

17 feet per day.

Unit is poorly permeable barrier to ground-water 

flow. Inhibits flow between hydrographic basins 

and does not readily transmit ground water. May 

form base of carbonate-rock aquifers.

EXPLANATION 

Sedimentary basin fill

| | Younger (Quaternary to Tertiary) Unconsolidated to semiconsolidated deposits

[ | Older (Tertiary) Semiconsolidated to consolidated deposits

| | Other consolidated rocks (Quaternary to Precambrian) 

Sedimentary, igneous, and metamorphic rocks underlying 

basin-fill deposits

 Contact Approximately located

 - - Fault Dashed where approximate. Arrows indicate direction 

of relative movement

 i Section line on index map Reduced scale
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A21

DIXIE VALLEY 

(Hydrographic area 128)

SALT LAKE VALLEY 

(Hydrographic area 267)

CARSON VALLEY 

(Hydrographic area 105)

NORTHERN RAILROAD VALLEY 

(Hydrographic area 173B)

LAS VEGAS VALLEY 

(Hydrographic area 212)

SPRING VALLEY 

(Hydrographic area 184)

FIGURE 7. Idealized sections showing basin geometry for six representative hydrographic areas (fig. 2). Vertical exaggeration, all sections, X4. Index map 

shows locations of six areas within Great Basin study area; for base credit and geographic detail, see figures 1 and 2. Modified from Plume (1996).
A22 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

118* 116° 114° 112° 110°

42C

40C

38<

36C

OREGON u.^-. W^~ y-i1

IDAHO r

.0..>~?

Y_l

^ s

Winnemucca

UTAH

100 MILES

100 KILOMETERS

^^ EXPLANATION

I^H Rocks that are potential barriers to regional

ground-water flow Tertiary to Jurassic granitic 

rocks, Lower Cambrian and upper Precambrian 

clastic sedimentary rocks, Paleozoic and Precambrian Ruby Mountains metamorphic core complex, 

and Precambrian crystalline basement

t--.;';-;| Subsurface magnetic-source body Probably consists of either Jurassic to Tertiary granitic rocks or 

Precambrian crystalline basement

 Western extent of carbonate-rock province

 - - Boundary of study area, Great Basin Regional 

Aquifer System

 ^» Simulated direction of deep ground-water flow

J* Large spring Discharge point for deep groundwater flow

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 8. Potential barriers to regional ground-water flow in carbonate-rock province. See figure 1 for geographic setting. Hydrology, geology, and

geophysics modified from Prudic and others (1995) and Plume (1996, pi. 5).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A23

GROUND-WATER RECHARGE

Aquifers in the Great Basin are recharged from precipitation, mostly winter precipitation that is stored in the 

form of snowpack in the adjacent mountains. Recharge 

processes are complex and not fully understood; depending on the characteristics of the rock units that form the 

mountains, recharge may be either in the mountains or 

along streams flowing over alluvial deposits adjacent to 

the mountains. The timing and frequency of recharge also 

vary widely. The major source areas for ground-water 

recharge are in the higher parts of the interbasin mountain ranges where precipitation is greater than in the adjacent valleys (fig. 9). Along some reaches of perennial 

streams, recharge is continuous; in many areas recharge 

occurs during and after periods of snowmelt or sustained 

precipitation; and in some areas recharge is infrequent 

and years may pass before sufficient moisture is accumulated to initiate recharge. Generally, little or no recharge is 

considered to originate from precipitation that falls on the 

valley floors. The Great Basin RASA program supported 

several studies to better understand the recharge process 

and to develop improved techniques to estimate recharge 

(Campana and Boone, 1986; Schulke, 1987).

Processes relating to recharge were evaluated by the 

University of Nevada Desert Research Institute (Campana and Boone, 1986; Schulke, 1987). Study sites were 

established in northwestern Nevada (in the Clear Creek 

drainage near Carson City and in the Virginia City Highlands area) and in southern Nevada (in the Kyle Canyon 

area northwest of Las Vegas). In addition, psychrometers 

were set up at sites in northwestern Nevada in the Virginia City Highlands area and in Reno and at sites in 

southern Nevada in the Kyle Canyon area and in Jean. 

The northwestern Nevada studies demonstrated deep 

percolation and consequent recharge beneath the snowpack during winter. Moreover, rain-on-snow storms produced additional pulses of inflow that were 

superimposed on steady deep percolation. How much 

winter recharge ultimately flowed from the mountains 

into the basin-fill deposits of the adjacent valleys and how 

much was discharged locally as base flow to streams and 

as evapotranspiration in areas of shallow ground water in 

the mountains could not be evaluated from these studies. 

Differing time lags between periods of recharge and 

water-level rises in wells in the Virginia City Highlands 

were interpreted as evidence of poor continuity between 

local aquifers and of complex localized flow patterns. In 

southern Nevada, several methods were used to study 

recharge in the Spring Mountains in the Kyle Canyon 

area, which is underlain by carbonate rocks (Schulke,

1987, p. 70-81). All methods indicated that almost all 

recharge was in the mountains. Soil-moisture studies in 

the lower, more arid environments of southern Nevada 

found prolonged conditions of very low soil moisture and 

upward potential gradients in soil moisture. These findings indicate that such areas receive little or no recharge.

Estimating natural recharge to the desert basins within 

the RASA study area is difficult. Several techniques have 

been used with varying degrees of success. The approach 

most commonly applied in Nevada and Utah was developed by Maxey and Eakin (1949). The Maxey-Eakin 

method entails estimating the total volumes of precipitation falling between specified altitudes in the mountains 

within the basin of interest, reducing these volumes to 

account for evaporative losses, and summing the resulting recharge volumes to arrive at an estimate of the total 

natural recharge from the mountains (Maxey and Eakin, 

1949). Because this technique is empirical, it is desirable to 

use more physically based techniques that provide independent estimates to compare with the Maxey-Eakin estimates. Dettinger (1989b) used a chloride-balance method 

to estimate natural ground-water recharge in 16 basins in 

the RASA study area. This method equates chloride in 

recharge water and runoff to chloride deposited in mountainous source areas by precipitation and dry fallout. 

Given estimates of annual precipitation on these source 

areas and chloride concentrations of bulk precipitation 

and recharge water, the rate of recharge can be estimated 

provided that no other major sources of chloride exist, 

that direct runoff to discharge areas in the basin is small 

or can otherwise be taken into account in the balance, and 

that the recharge sources for the basin are correctly delineated. Preliminary applications of the method to 16 basins 

in Nevada produced results that generally correlate well 

with the corresponding Maxey-Eakin estimates. The correlation coefficient between the recharge efficiencies 

implied by each method is 0.88 (Dettinger, 1989b, p. 73).

Various investigators who have used the Maxey-Eakin 

method in specific basins have had to make subjective 

decisions in applying the method to specific case studies. 

These decisions relate mostly to matching precipitation 

rates to altitude zones; however, some investigators have 

also made adjustments to recharge coefficients to account 

for large areas of precipitation substantially in excess of 20 

in/yr and to account for variations in surficial geology in 

areas of precipitation of 8 to 12 in/yr. Consequently, the 

various estimates were evaluated as a single set to determine the degree of consistency that was maintained 

between individual estimates. This was done by a technique developed by the Southwest Alluvial Basins RASA 

program (Anderson and others, 1992, p. B33-B34), which
A24 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 112°

42°

40° 

38° 

36° 

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

EXPLANATION

^^H Major source area for ground-water recharge

 Boundary of study area, Great Basin Regional Aquifer System

FIGURE 9. Major source areas for ground-water recharge. Modified from Mifflin (1988).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A25

evaluated basin-fill aquifer systems in parts of Arizona 

and adjacent States. As part of their study, estimates from 

12 steady-state flow models were used to develop an 

empirical relation between mean annual recharge along 

the mountain front and total volume of annual precipitation on the watershed where annual precipitation exceeds 

8 in. Then this relation was extended to all 72 basins in the 

Southwest Alluvial Basins study area through an iterative 

process of balancing the individual basin and regional 

water budgets (Anderson, 1985, p. 102-103). The resulting 

relation that was developed by Anderson is

log Qr = -1.40 + 0.98 log PP>8 ,

where Qr = recharge, in acre-ft/yr; and

Pp>8 = total annual volume of precipitation, 

in acre-ft/yr, where average annual 

precipitation exceeds 8 in.

This same general procedure was applied to 167 estimates of recharge in the Great Basin RASA study area 

(table 3) that were obtained by the Maxey-Eakin method. 

These estimates were made for basins mostly in Nevada, 

Utah, and California (fig. 10). The relation between the 

recharge estimates and estimates of annual precipitation 

in excess of 8 in. is shown in figure 11. For comparison, 

Dettinger's (1989b, p. 68-69) 16 recharge estimates 

obtained by the chloride-balance method are also listed in 

table 3 (and relevant areas are shown in fig. 10). The 

resulting equation for the relation between recharge estimated by the Maxey-Eakin method and estimated precipitation volume where annual precipitation exceeds 8

in. is

log Qr = -1.74 + 1.10 log Pp>8 .

The various estimates are highly correlated (r 2 = 0.95). 

The high correlation indicates that the individual estimates produced by a number of investigators in a number 

of basins are highly consistent when compared to precipitation and that individual subjective decisions did not 

impair the overall consistency of the set of estimates. The 

preceding evaluation does not address the accuracy of the 

estimates made using this relation; however, the exponential equation developed by the Maxey-Eakin estimates of 

recharge is similar to the equation for estimates in Arizona that were developed by different techniques. Determining whether the small differences in the two 

equations could be attributed to differences in precipitation, lithology, altitude, latitude or longitude, or other factors was not possible within the scope of this study. That 

precipitation estimates used in the Southwest Alluvial 

Basins RASA were developed from information sources 

other than those used in the Great Basin RASA may 

account for the small differences.

GROUND-WATER DISCHARGE

The Great Basin RASA study area is characterized by 

internal drainage. Most ground-water discharge is by 

evapotranspiration, and most spring discharge ultimately is consumed by evapotranspiration. Areas of 

ground-water discharge typically are in the topographically low parts of valleys where the water table is near the 

land surface. The principal areas of ground-water discharge and locations of major springs are shown in figure 

12. In the carbonate-rock province, much of the discharge 

from multibasin ground-water flow systems is by 

springs. This concentration of spring discharge at the terminus of regional ground-water flow systems is characteristic of the carbonate-rock province.

Rates of evapotranspiration for most of the discharge 

areas shown in figure 12 have been estimated on the basis 

of field reconnaissance to determine the area and general 

character of the vegetation and on the basis of lysimeter 

measurements in several areas. Estimates of groundwater evapotranspiration are not available for every 

basin in the study area, but if the flow system is considered to be in a general state of dynamic equilibrium, then 

the total natural ground-water discharge can be considered to be about equal to the recharge, which is about 

3,800,000 acre-ft/yr (Harrill and others, 1988).

The need for improved quantitative determinations of 

evapotranspiration was recognized in the planning phase 

of the Great Basin RASA study, and some effort was put 

into addressing this need. Carman (1985,1989,1993) evaluated selected methods for estimating evapotranspiration from areas of phreatophytes under natural 

conditions. Two sites were selected for field measurements, one in the Carson Desert Hydrographic Area 

(table 1) and one in Smith Creek Valley. Instruments were 

set up at the sites, and data were collected during parts of 

the 1982 and 1983 growing seasons. Using the data collected during the 1983 growing season, Carman (1993) 

demonstrated the feasibility of making field measurements of evapotranspiration under conditions that exist 

in the desert areas of the Great Basin and provided preliminary measurements at specific sites. For example, at 

the site in Smith Creek Valley, where in 1983 about 25 percent of the area was covered by rabbitbrush and depth to 

the water table was 10 to 15 ft, the total evapotranspiration measured by the eddy-correlation method during 

1983 was 1.05 ft (Carman, 1993). Total evapotranspiration 

includes consumption of soil moisture, of precipitation, 

and of ground water. Ground-water evapotranspiration 

cannot be measured directly; however, Robinson (1970, p. 

D29-D30) reported a mean total annual evapotranspiration for rabbitbrush of 1.66 ft for the 1964,1966, and 1967 

growing seasons measured in a lysimeter where depth to
A26 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

42°

40°

38°

36°

*i .An K

v / r\ >

V ./ ^">>rf" V! v " ; -" -J, \ r ) A

rP-rOywA; , -ns ^ > /fT-w, / 

\ M ; i^^'/ - -Hi J! r-\- N

Hr x

^-.^Tx->->" W //T" I

n- - 

UTAH

ARIZONA

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 10. Areas where estimates of recharge (table 3) were used to define relation between recharge and mean annual precipitation in excess of

8 inches (fig. 11).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A27

the water table ranged from 5 to 6 ft. About 64 percent of 

the total measured evapotranspiration was derived from 

ground water. If this percentage is representative for 

Smith Creek Valley, then the estimated consumption of 

ground water would be about 0.7 ft/yr. Similarly in the 

Carson Desert Hydrographic Area, the total evapotranspiration measured by the edd correlation method was 

1.21 ft in 1983. Depth to water was estimated to be 25 to 30 

ft. However, during hand augering, a moist zone was 

encountered at about 12 ft below land surface. The site 

was in an area of stabilized dunes with greasewood covering about 5 percent of the area; some shadscale, Great 

Basin wildrye, and saltcedar were also present, but about 

82 percent of the area was bare soil. Robinson (1970, p. 

D29) reported that the ground-water component of total 

evapotranspiration by rabbitbrush, measured in a lysimeter, where depth to water ranged from 5 to 7.8 ft during 

four field seasons, was 50 percent of the total evapotranspiration. If this percentage is representative for the site in 

the Carson Desert Hydrographic Area, then the estimated 

rate of ground-water evapotranspiration would be about 

0.6 ft/yr.

An alternate method of estimating evapotranspiration 

rates in Smith Creek Valley was used by Hines (1992). He 

applied evapotranspiration rates measured in lysimeters 

by Robinson (1970) to stands of phreatophytic vegetation 

in Smith Creek Valley. To do this he transferred rates that 

Robinson had normalized in terms of acre-feet of water 

consumed per acre-foot of foliage and assumed that the 

same percentage of the total evapotranspiration as determined by Robinson was supplied by ground water. 

Native vegetation in Smith Creek Valley was grouped 

into five zones on the basis of foliage density and plantspecies composition. The estimated ground-water evapotranspiration rate for three stands dominated by greasewood ranged from 0.1 to 0.9 ft/yr, whereas the rate for

Recharge

Estimated by Dettinger's (1989b) chloridebalance method

Estimated by Maxey Eakin method (Maxey 

and Eakin, 1949)

Not estimated

Boundary of study area, Great Basin Regional 

Aquifer System

Boundary of hydrographic area or subarea

(fig- 2)

stands of pure rabbitbrush was 0.3 ft/yr. Discharge to 

bare soil in the playa was estimated by using a flow net 

and Darcy's law. Evaporation rates for bare soil ranged 

from 0.1 to 0.5 ft/yr and for the entire main playa averaged about 0.2 ft/yr. The overall estimated volume of 

evapotranspiration compared well with the existing 

reconnaissance estimate. However, the rates used by 

Hines (1992) are slightly higher than some of the average 

rates used for the reconnaissance study; also, he did 

more-detailed field evaluation and mapped a slightly 

smaller area of phreatophytes.

REGIONAL GROUND-WATER FLOW

CONCEPTS OF REGIONAL FLOW

To evaluate regional ground-water flow in the Great 

Basin study area, theoretical aspects of ground-water flow 

systems were applied to the area. Such theoretical aspects 

were examined in the 1960's by Toth (1962, 1963) and 

Freeze and Witherspoon (1966, 1967), who modeled 

hypothetical ground-water flow systems along vertical 

sections. Toth (1963, p. 4807) used a system of uniform 

permeability to demonstrate that, if the potential on the 

surface of the system differed from a linear gradient, circulation cells would form in response to local areas of 

recharge and discharge. These recharge and discharge 

areas correspond to areas of localized high and low potential, respectively Toth (1963) was able to identify three 

types of flow systems local, intermediate, and 

regional on the basis of the length of flow lines and by 

whether flow passed beneath local or intermediate areas 

of high or low potential. Toth's findings that are most 

applicable to the Great Basin are that (1) deep regional 

flow can pass beneath shallow local areas of high potential (ground-water divides) and (2) variations in permeability within the system can cause appreciable discharge 

upgradient from the hydraulic terminus of the system. To 

evaluate regional ground-water flow in the Great Basin, 

Prudic and others (1995) represented ground-water flow 

from recharge areas in the mountains to discharge areas 

on the basin floors as shown in figure 13. A schematic geohydrologic cross section is shown in figure 13A The same 

concept represented by a finite-difference computer 

model is depicted in figure 13B, in which the shallow-flow 

and deep-flow regions generally correspond to Toth's 

(1963) intermediate and regional flow systems. Local flow 

systems were ignored in these regional-scale flow patterns.
A28 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN NEVADA-UTAH

100,000

DC

<

LU>-

DC

LU

o_

111 111 li.

LLJ 

DC 

O

111 

CD 

DC 

<

I 

O 

LLJ 

DC

10,000

1,000

100

10

Chloride-balance method (Dettinger, 1989b)

D Maxey-Eakin method (Maxey and Eakin, 1949)

1

10 100 1,000 10,000 100,000 1,000,000 10,000,000

AVERAGE ANNUAL PRECIPITATION VOLUME WHERE RATE EXCEEDS 8 INCHES PER YEAR,

IN ACRE-FEET PER YEAR

FIGURE ll. Relation between recharge and mean annual precipitation volume where precipitation rate

exceeds 8 inches per year (fig. 10).

POTENTIAL FOR REGIONAL GROUND-WATER FLOW

Large ground-water flow systems are driven by 

hydraulic gradients that are continuous over long distances. These large systems generally are the deep-flow 

regions described in the section "Concepts of Regional 

Flow." Bredehoeft and others (1982) reviewed the development of concepts relating to regional ground-water 

flow. One principle they listed as governing regional 

ground-water flow was that "differences in hydraulic 

head produced by topographic relief on the boundaries of 

the system are, in most instances, the driving force for the 

flow" (Bredehoeft and others, 1982, p. 297). This principle 

was used to evaluate the potential for regional flow in the 

Great Basin. The approach taken was to determine the 

lowest water-level altitude in the basin-fill deposits of 

each valley, which generally is only slightly below the 

topographically lowest point in the basin, and then to

draw smooth contours through the altitude points for 

each valley. Regional flow potential obtained by this 

method is shown in figure 14. If basin-fill deposits and 

consolidated rocks are sufficiently permeable, regional 

flow would be toward the Colorado River or major sinks. 

Thomas and others (1986) developed more detailed information on regional hydraulic gradients, which was used 

to support simulations discussed in the section "Simulation of Regional Ground-Water Flow in CarbonateRock Province."

DESCRIPTION OF REGIONAL SYSTEMS

The major flow systems in the Great Basin RASA study 

area are considered herein to be the local, intermediate, or 

regional system that is dominant commonly the one 

conveying the largest percentage of ground water in a 

specified area. Where consolidated rocks are permeable
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A29

TABLE 3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8 inches

in Great Basin study area

[Hydrographic area or subarea: See figure 2 and table 1. Do., ditto]

Number

Hydrographic area or subarea

Name of area, subarea, 

or part of area

Precipitation volume

where precipitation rate

exceeds 8 inches per year

(acre-feet per year)

Recharge 

(acre-feet 

per year)

Reference

Maxey-Eakin method

2

3

3

4

9

12

15

16

19

20

21

22

23

24

25

26

28

28

29

30

31

32

33

53

55

56

57

58

67

68

69

71

Continental Lake Valley 

Gridley Lake Valley 

Massacre Lake Valley 

Virgin Valley

Long Valley 

Mosquito Valley 

Boulder Valley 

Duck Lake Valley

Dry Valley 

Sano Valley 

Smoke Creek Desert 

San Emidio Desert

Granite Basin 

Hualapai Flat 

High Rock Lake Valley 

Mud Meadow

Black Rock Desert 

Summit Lake 

Pine Forest Valley 

Kings River Valley

Desert Valley 

Silver State Valley 

Quinn River Valley 

Pine Valley

Carico Lake Valley 

Upper Reese River Valley 

Antelope Valley 

Middle Reese River Valley

Little Humboldt Valley 

Hardscrabble Area 

Paradise Valley 

Grass Valleyl

254,000

98,000

88,000

230,000

168,000

14,000

50,000

247,000

5,900

130

275,000

48,000

5,800

106,000

435,000

131,000

258,000

43,000

195,000

260,000

100,000

35,000

890,000

655,000

95,000

591,500

240,000

142,000

443,000

115,000

121,000

180,000

11,000 Sinclair, 1963d

4,500 ..........Do..................................

3,500 Sinclair, 1963c

7,000 Sinclair, 1963d

6,000 Sinclair, 1963c

700 ..........Do..................................

2,000 ..........Do..................................

9,000 Sinclair, 1963b

200 Glancy and Rush, 1968

4 ..........Do..................................

13,000 ..........Do..................................

2,100 ..........Do..................................

400 Sinclair, 1963a

7,000 Harrill, 1969

13,000 Sinclair, 1963a

8,000 ..........Do..................................

14,000 ..........Do..................................

4,200 ..........Do..................................

10,000 Sinclair, 1962b

15,000 Malmberg and Worts, 1966

5,000 Sinclair, 1962a

I,400 Huxel and others, 1966

73,000 ..........Do..................................

46,000 Eakin, 1961b

4,300 Everett and Rush, 1966

37,000 Eakin and others, 1964

II,000 Crosthwaite, 1963

7,000 ..........Do..................................

24,000 Harrill and Moore, 1970

9,000 ..........Do..................................

10,000 ..........Do..................................

12,000 Cohen, 1964

72

73

74

75

76

77

78

79

Imlay Area

Lovelock Valley

White Plains

Bradys Hot Springs Area

Fernley Area 

Fireball Valley 

Granite Springs Valley 

Kumiva Valley

82,000

60,000

100

5,000

13,000

6,000

96,000

30,000

4,000 Eakin, 1962c

3,200 Everett and Rush, 1965

3 Glancy and Katzer, 1976

160 Harrill, 1970

600 Van Denburgh and others, 1973

200 Harrill, 1970

3,500 ..........Do.........................................

1,000 ..........Do.........................................
A30 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8 inches

in Great Basin study area Continued

[Hydrographic area or subarea: See figure 2 and table 1. Do., ditto]

Number

80 

81

82

83

84 

85

86

87 

88

89 

92 

93

103A 

101B

102

103

104 

105 

106 

107

108 

109 

110 

113

114 

117 

118 

119

120

121

122 

123

124 

128

130

139

133 

134 

135

136

Hydrographic area or subarea

Name of area, subarea, 

or part of area

Winnemucca Lake Valley

Dodge Flat

Warm Springs Valley

Truckee Meadows

Washoe Valley 

Lemmon Valley 

Antelope Valley

Packard Valley

Eagle Valley 

Carson Valley 

Antelope Valley 

Smith Valley

Mason Valley 

East Walker Area 

Walker Lake Valley 

Huntoon Valley

Teels Marsh Valley 

Fish Lake Valley 

Columbus Salt Marsh Valley 

Rhodes Salt Marsh Valley

Garfield Flat

Gabbs Valley 

Rawhide Flats

Fairview Valley

Edwards Creek Valley 

Smith Creek Valley

Monte Cristo Valley

Precipitation volume

where precipitation rate 

exceeds 8 inches per year 

(acre-feet per year)

Maxey-Eakin method Continued

61,000 

103,000

21,000

191 nnn

96,000 

16,000

1,800

161,900 

Af. nnn

87,000 

44,000 

9,000

13,000 

29,000

39 nnn

125,000

58,000 

357,000 

172,000 

210,000

32,000 

331,000 

101,000 

22,000

38,000 

255,000 

13,000 

12,000

9,000

20,000

383,000 

5,000

17,000 

80,000

45,000

17 nnn

111,000 

119,000 

90,000

12,000

Recharge

(acre-feet 

per year)

2,900 

6,600

1,400

6,000

6,000 

600

50

27,000 

10,000

15,000 

1,500 

300

710 

1,300

1,300

7,900

8,700 

41,000 

18,000 

17,000

2,000 

31,000 

6,500 

800

1,300 

33,000 

700 

500

300

700

5,000 

150

500 

6,000

3,000

800

8,000 

12,000 

8,000

500

Reference

Van Denburgh and others, 1973 

..........Do.........................................

..........Do.........................................

..........Do.........................................

Rush and Glancy, 1967 

..........Do.........................................

..........Do.........................................

Van Denburgh and others, 1973 

..........Do.........................................

Rush, 1967 

Harrill, 1973 

Rush and Glancy, 1967

Glancy and Katzer, 1976 

..........Do.........................................

..........Do.........................................

..........Do.........................................

Worts and Malmberg, 1966 

Glancy and Katzer, 1976 

Glancy, 1971 

Rush and Schroer, 1976

Huxel and Harris, 1969 

Glancy, 1971 

Everett and Rush, 1967 

Van Denburgh and Glancy, 1970

Van Denburgh and Glancy, 1970 

Rush and Katzer, 1973 

Van Denburgh and Glancy, 1970 

..........Do.........................................

..........Do.........................................

..........Do.........................................

Eakin, 1962b 

Everett and Rush, 1967

Cohen and Everett, 1963 

..........Do.........................................

..........Do.........................................

..........Do.........................................

Everett, 1964 

Everett and Rush, 1964 

..........Do.........................................

Van Denburgh and Glancy, 1970
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A31

TABLE 3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8 inches

in Great Basin study area Continued

[Hydrographic area or subarea: See figure 2 and table 1. Do., ditto]

Number

Hydrographic area or subarea

Name of area, subarea, 

or part of area

Precipitation volume

where precipitation rate

exceeds 8 inches per year

(acre-feet per year)

Recharge 

(acre-feet 

per year)

Reference

Maxey-Eakin method Continued

137A Tonopah Flat

137B Big Smoky Valley (Northern Part)

138 Grass Valley1

141 Ralston Valley

143 Clayton Valley

145 Stonewall Flat

146 Sarcobatus Flat

147 Gold Flat

148 Cactus Flat

149 Stone Cabin Valley

150 Little Fish Lake Valley

153 Diamond Valley

154 Newark Valley

155 Little Smoky Valley

156 Hot Creek Valley

157 Kawich Valley

158A Groom Lake Valley

158B Papoose Lake Valley

159 Yucca Flat

160 Frenchman Flat

161 Indian Springs Valley

163 Mesquite Valley

164 Ivanpah Valley

165 Jean Lake Valley

167 Eldorado Valley

168 Three Lakes Valley (Northern Part)

169 Tikapoo Valley

170 Penoyer Valley

171 Coal Valley

172 Garden Valley

173 Railroad Valley

175 Long Valley

176 Ruby Valley

177 Clover Valley

178 Butte Valley

179 Steptoe Valley

180 Cave Valley

181 Dry Lake Valley

182 Delamar Valley

183 Lake Valley

171,000

570,000

211,000

115,000

35,000

1,900

40,000

94,000

15,000

103,000

181,000

319,000

335,000

140,000

153,000

88,000

76,000

130

9,300

3,200

115,000

31,000

36,000

2,000

37,000

41,000

115,000

100,000

62,000

137,000

754,000

297,000

674,000

285,000

240,000

810,000

207,000

118,000

34,000

229,000

12,000 Rush and Schroer, 1971

65,000 ..........Do........................................

13,000 Everett and Rush, 1966

5,000 Rush, 1968b

1,500 ..........Do........................................

100 ..........Do........................................

I,200 Malmberg and Eakin, 1962

3,800 Rush, 1971

600 ..........Do........................................

5,000 Rush, 1968b

II,000 Rush and Everett, 1966

21,000 Harrill, 1968

17,500 Eakin, 1960

5,400 Rush and Everett, 1966

7,000 ..........Do........................................

3,500 Rush, 1971

3,200 Rush, 1971

4 ..........Do........................................

700 ..........Do........................................

100 ..........Do........................................

10,000 ..........Do........................................

1,500 Glancy, 1968b

1,500 ..........Do........................................

100 ..........Do........................................

1,100 Rush and Huxel, 1966

2,000 Rush, 1971

6,000 ..........Do........................................

4,300 Van Denburgh and Rush, 1974

2,000 Eakin, 1963b

10,000 ..........Do........................................

52,000 Van Denburgh and Rush, 1974

10,000 Eakin, 1961a

68,000 Eakin and others, 1951

21,000 ..........Do........................................

19,000 Glancy, 1968a

85,000 Eakin and others, 1967

14,000 Eakin, 1962a

5,000 Eakin, 1963a

1,000 ..........Do........................................

13,000 Rush and Eakin, 1963
A32 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8 inches

in Great Basin study area Continued

[Hydrographic area or subarea: See figure 2 and table 1. Do., ditto]

Number

Hydrographic area or subarea

Name of area, subarea, 

or part of area

Precipitation volume

where precipitation rate

exceeds 8 inches per year

(acre-feet per year)

Recharge 

(acre-feet 

per year)

Reference

Maxey-Eakin method Continued

184 Spring Valley 791,000

185 Tippett Valley 114,000

186 Antelope Valley 117,000

187 Goshute Valley 386,000

188 Independence Valley (Pequop Valley) 203,000

189 Thousand Springs Valley 325,000

191 Pilot Creek Valley 40,000

142 Alkali Spring Valley 2,800

201 Spring Valley 177,000

202 Patterson Valley 137,000

208 Pahroc Valley 57,000

209 Pahranagat Valley 43,000

210 Coyote Spring Valley 48,000

211 Three Lakes Valley (Southern Part) 56,000

215 Black Mountains Area 2,200

216 Garnet Valley 11,000

217 Hidden Valley (North) 11,000

218 California Wash 2,000

220 Lower Moapa Valley 1,200

221 Tule Desert 62,000

225 Mercury Valley 5,000

226 Rock Valley 900

227A Jackass Flats 22,000

227B Buckboard Mesa 39,000

228 Oasis Valley 33,000

229 Crater Flat 7,000

230 Amargosa Desert 90,000

243 Death Valley 140,000

251 Grouse Creek Valley 254,000

252 Pilot Valley 56,000

253 Deep Creek Valley 290,000

254 Snake Valley 1,817,000

255 Pine Valley 351,000

256 Wah Wah Valley 209,000

257 Tule Valley 176,000

258 Fish Springs Flat 42,000

259 Dugway-Government Creek Valley 143,000

260 Park Valley 344,000

261 Great Salt Lake Desert (southern) 226,000 

	Great Salt Lake Desert (northern) 38,000

75,000 Rush and Kazmi, 1965

6,900 Harrill, 1971

4,700 ..........Do.........................................

10,400 Eakin and others, 1951

9,300 ..........Do.........................................

12,000 Rush, 1968d

2,400 Harrill, 1971

100 Rush, 1968b

10,000 Rush, 1964

8,000 ..........Do.........................................

2,200 Eakin, 1963c

1,800 ..........Do.........................................

2,600 Eakin, 1964

6,000 Rush, 1971

70 Rush, 1968c

400 ..........Do.........................................

400 ..........Do.........................................

60 ..........Do.........................................

40 ..........Do.........................................

2,100 Glancy and Van Denburgh, 1969

250 Rush, 1971

30 ..........Do.........................................

900 ..........Do.........................................

1,400 ..........Do.........................................

1,000 ..........Do.........................................

220 ..........Do.........................................

1,500 Walker and Eakin, 1963

8,000 Miller, 1977

14,000 Hood and Price, 1970

3,400 Stephens and Hood, 1973

17,000 Hood and Waddell, 1969

100,000 Hood and Rush, 1965

21,000 Stephens, 1976

7,000 Stephens, 1974b

7,600 Stephens, 1977

4,000 Bolke and Sumsion, 1978

7,000 Stephens and Sumsion, 1978

24,000 Hood, 1971b

47,000 Gates and Kruer, 1981

4,500 Stephens, 1974a
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A33

TABLE 3. Recharge estimated by Maxey-Eakin and chloride-balance methods for selected areas where annual precipitation exceeds 8 inches

in Great Basin study area Continued

[Hydrographic area or subarea: See figure 2 and table 1. Do., ditto]

Number

263 

269 

276 

271

275 

278

16 

36

56

92

103B

117

122

153

163

170

173A

173B

178A

178B

184

212

Hydrographic area or subarea

Name of area, subarea, 

or part of area

Rush Valley 

West Shore Area 

Hansel and Northern Rozel Flat 

Sink Valley

Blue Creek Valley 

Curlew Valley

Duck Lake Valley

Railroad Valley (Southern Part)

Railroad Valley (Northern Part)

Butte Valley (Northern Part)

Butte Valley (Southern Part)

Las Vegas Valley

Precipitation volume

where precipitation rate 

exceeds 8 inches per year 

(acre-feet per year)

Maxey-Eakin method Continued

510,000 

5,800 

160,000 

5,000

184,000 

868,000 

426,000

Chloride-balance method

243,000 

951 flflfl

SQ9 flflfl

3D 8flfl

o 700

OKI ODD

381,000

227,000

30,000

97300

1 3fl flflfl

616,000

48,700

i9 9flfl

787,000

332,500

(acre-feet 

per year)

34,000 

600 

8,000 

1,000

14,000 

75,600 

76,000

8,900 

9,700

30,000

1,600

320

26,800

4 Qflfl

10,500

1,600

3,200

4,900

24,800

2,400

1,200

61,600

28,000

Reference

Hood and others, 1969 

Price and Bolke, 1976 

Hood, 1971a 

Price and Bolke, 1976

Bolke and Price, 1972 

Bolke and Price, 1969 

Baker, 1974

Dettinger, 1989b 

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

..........Do.........................................

Two areas are called Grass Valley. Area 71 is part of Humboldt flow system; area 138 forms Grass Valley flow system (see table 4 and fig. 15). 

Although data from area 36 (Independence Valley) is used in estimating recharge, area is just outside Great Basin study area.

enough to afford significant identifiable hydraulic continuity on a regional scale, the local and intermediate types 

of systems are considered to be subsystems within 

regional flow systems. Where consolidated rocks have 

only low permeability and where water-budget studies 

do not indicate interbasin flow, regional flow was considered insignificant and the local and intermediate systems 

were considered to be the major flow systems. Where several basins are traversed by a major stream, and continuity between the basins is provided primarily by the 

stream, these interconnected basins constitute a complex 

regional flow system involving substantial interaction 

between ground water and surface water. The Humboldt 

River, Truckee River, Carson River, and Walker River 

Basins of Nevada are examples of this type of system. A 

basic premise is that each flow system terminates in a discharge area. Consequently, if all terminal discharge areas 

are identified, the task of delineating a flow system is 

reduced to identifying those areas that contribute flow 

toward a specified discharge area. For local systems consisting of only one basin or of a discharge area and one or 

more tributary basins, the task is simple, providing adequate hydrologic data are available. However, some 

larger regional systems extend for more than 100 mi and 

have flow paths that traverse as many as seven basins. In 

most such systems, some water discharges at intermediate points along a regional-flow path from intervening 

local or intermediate flow systems; consequently, only 

some of the water flows all the way to the regional discharge area. Boundaries between systems are defined 

only generally; some are physical barriers to flow, such as 

masses of intrusive rocks, and others represent ground-
A34 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116° 114° 112°

IDAHO

42° X

 ~~: =^jr\

40°

38°

36°

> ' > t ?

>, < vY«

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 12. Locations of large springs and areas of ground-water discharge by evapotranspiration. Modified from Harrill and others (1988).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A35

water divides or areas where flow paths are parallel but 

ultimately diverge downgradient. For much of the Great 

Basin, adequate data to precisely define flow-system 

boundaries currently are not available.

The 39 major flow systems (fig. 15; Harrill and others, 

1988) were delineated by applying the general procedures 

outlined in the section "Regional Ground-Water Flow" to 

data collected mostly in the shallower parts of the systems. Consequently, the boundaries of the deeper parts of 

the major flow systems are based primarily on information from the shallow parts of the systems. Recharge and 

storage data for the 39 flow systems are summarized in 

table 4.

The 39 major flow systems range in area from 30 to 

18,000 mi2 (table 4). Of the 39 flow systems, 16 are singlebasin local systems and 23 are multibasin intermediate or 

regional systems, some of which include as many as 34 

hydrographic areas or subareas. Large multibasin flow 

systems outside the carbonate-rock province are generally coincident with major river systems. Large multibasin systems within the carbonate-rock province typically 

do not have much surface flow; instead, they may contain 

ground-water flow paths more than 100 mi long that 

traverse several basins. Discharge from these systems is 

typically from large springs. This discharge generally is 

consumed by evapotranspiration in the vicinity of a 

spring. Altitudes of terminal discharge areas range from 

about 5,800 ft in high parts of central Nevada to about 200 

ft below sea level in Death Valley, Calif.

An alternate classification of flow systems in Utah is 

possible. The Sevier Lake, Great Salt Lake Desert, and 

Great Salt Lake systems could have been grouped into a 

large system with its terminus at the Great Salt Lake. 

Some geologic and hydrologic evidence supports 

regional continuity between these areas, but significant 

hydraulic gradients between the areas are virtually nonexistent; consequently, the volume of subsurface flow is 

relatively small. Moreover, each of the three areas has a 

distinctive hydrologic character. Therefore this part of the 

region is described as three major flow systems with three 

terminal discharge areas.

EXPLANATION

|___| Area of shallow ground-water discharge by evapotranspiration

 Boundary of study area, Great Basin Regional 

Aquifer System

p Large spring In Utah and most of Nevada, springs 

having discharge generally greater than 1,000 

gallons per minute; in more-arid parts of Nevada, 

Oregon, and California, regionally significant 

springs having discharges greater than 200 gallons 

per minute

In southern Nevada, the hydrologic character of parts 

of the west boundary of the Colorado system (Harrill and 

others, 1988) is not well understood and its location is 

uncertain.

SIMULATION OF GROUND-WATER FLOW

Simulation results were used in the evaluations and 

analyses of ground-water flow systems in the Great Basin. 

Model simulations include a conceptual evaluation of 

regional ground-water flow in the carbonate-rock province in the eastern Great Basin (hereafter referred to as the 

carbonate-rock province model), an evaluation of 

regional ground-water flow in the Fish Springs flow system in western Utah, and detailed evaluations and analyses of selected basin-fill aquifers in five hydrographic 

areas (fig. 16) in Utah (the Milford area) and in Nevada 

(Carson, Paradise, Smith Creek, and Stagecoach Valleys). 

Evaluations and analyses are based on simulations using 

McDonald and Harbaugh's (1988) finite-difference 

ground-water flow model.

The following sections describe the simulation of 

regional ground-water flow in the carbonate-rock province and discuss the results; compare those results, as they 

apply to the Fish Springs flow system, with findings of the 

more detailed, independent simulation of regional flow in 

that system; and describe and compare simulation results 

for five basin-fill aquifers in Utah and Nevada.

SIMULATION OF REGIONAL GROUND-WATER FLOW IN 

CARBONATE-ROCK PROVINCE

A three-dimensional ground-water flow model was 

used to simulate the concept of shallow ground-water 

flow systems superimposed on deeper flow systems and 

to evaluate regional ground-water flow in the carbonaterock province, a 100,000-mi2 area that is mostly in eastern 

Nevada and western Utah (figs. 5 and 16). Detailed analyses of the model results were presented by Prudic and 

others (1995), and only a summary of the major findings 

is presented herein. The modeled area is divided into rectangular cells that represent areas 5 mi wide and 7.5 mi 

long, elongated in a north-northeastward direction. Two 

model layers are used to simulate the shallow- and deepflow systems; the shallow system is equivalent to Toth's 

(1962) intermediate system. The concept of regional-scale 

ground-water flow and its representation in the threedimensional model are shown in figure 13.

The ground-water flow model of the carbonate-rock 

province is highly generalized because of the complex 

geology, scarcity of water-level data, uncertainty in the 

thickness and extent of aquifers, and uncertainty in estimates of ground-water recharge and evapotranspiration.
OJ

Evapotranspiration throu9 h 

^ AJ. . springs

Evapotranspiration

Discharge through

springs

T Recharge Model cell

Upper model 

layer (shallow-flow 

region) *

Lower model 

layer (deep-flow 

region)

Hi 

f

i

1

i I 

^ 

IB1 - f

'8 

1 

1 B i

1 

f

* - 1 

1 1 1

~ - CD O"5 O > 

Discharge through

springs Evapotranspiration

Recharge

Surface flow

EXPLANATION

Direction of ground-water flow

Upper model layer Lower model layer

Boundary of flow region

FIGURE 13. Ground-water flow from recharge areas in mountains to discharge areas on basin floors (Prudic and others, 1995, p. D54). Not to scale. A, Generalized 

hydrogeologic section. B, Finite-difference computer model. C, Water budget within area encompassed by deep-flow region on basis of computer-model output.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A37

By necessity, several simplifying assumptions are used in 

the conceptualization and simulation of regional groundwater flow (Prudic and others, 1995, p. D94). The assumptions are important in understanding the limitations 

of the model results and are summarized as follows: 

(1) Consolidated rock having abundant fractures and 

solution openings can be represented on a regional scale 

as a porous medium. (2) Darcy's law is applicable on a 

regional scale to flow through the fractures and solution 

openings and across abrupt changes in lithology. 

(3) Steady-state conditions prevail: Estimated recharge 

equals estimated discharge prior to any ground-water 

development. (Therefore, pumping is not included in the 

simulation.) (4) Horizontal transmissivity is heterogeneous on a regional scale but is considered to be homogeneous and isotropic within each model cell. (5) Recharge 

is from precipitation in the mountains and is simulated as 

a constant rate to model cells in the upper layer. (6) Rivers 

and lakes that border the modeled area, as well as the 

Death Valley playa, can be either a source or a sink for 

ground-water flow. (7) Discharge from regional springs is 

known, and flow to these springs is through carbonate 

rocks in the deep-flow system or lower model layer (fig. 

13). (8) Spring flow not simulated as discharging from the 

deep-flow system is included as part of the discharge 

from shallow ground water, which is simulated as evapotranspiration from the upper model layer.

The validity of each assumption for the entire model is 

unknown, although each is probably valid for parts of the 

modeled area. Because of the uncertainty of these 

assumptions and because the extent, thickness, and 

hydraulic properties of the aquifers in the region are 

largely unknown, simulation results do not perfectly replicate ground-water flow. The results do, however, provide a simplified concept of recharge, discharge, and flow 

in the eastern Great Basin within the limitations of current 

understanding and the limitations of the model simulations.

The model was calibrated by adjustment of transmissivity and vertical hydraulic conductivity to match 

observed water levels, areas of evapotranspiration, and 

discharges from regional springs. Generally, transmissivities in the upper model layer are greater in cells corresponding to basin fill and carbonate rocks and are less in 

cells corresponding to clastic sedimentary, metamorphic, 

and igneous rocks. Transmissivities in the lower model 

layer (fig. 17) are greatest near regional springs and in the 

vicinity of basins where ground-water discharge is considerably more than the estimated recharge from the 

immediately surrounding drainage area. In the lower 

model layer, high transmissivities (values exceeding 0.006 

ft2 /s; Prudic and others, 1995, p. D49) may reflect areas 

where carbonate rocks are thick and generally continuous. High transmissivities extending from east-central

Nevada into southern Nevada correspond to such an area 

(Dettinger, 1989a, p. 13-16). Similarly, high transmissivities in west-central Utah correspond to an area where carbonate rocks are continuous and relatively thick (Carlton, 

1985, p. 11). This area is simulated as a major conduit for 

northward flow from western Utah into the southern part 

of the Great Salt Lake Desert.

The model simulates the concept of numerous shallowflow regions superimposed on fewer deep-flow regions. 

In the upper model layer, 45 shallow-flow regions are distinguished on the basis of horizontal flow between cells 

(Prudic and others, 1995, p. D53). In the lower layer, flow 

is grouped into 17 deep-flow subregions, also on the basis 

of horizontal flow between cells (fig. 18). Because boundaries of the deep-flow subregions do not everywhere correspond to shallow-flow regions, shallow flow moves 

across underlying deep-flow boundaries at some places 

and shallow flow moves in a different direction from that 

of deep flow. Dinwiddie and Schroder (1971) reported different directions of shallow and deeper flow in central 

Nevada on the basis of water-level data.

Although the number of deep-flow subregions is the 

same as the number of flow systems delineated by Harrill 

and others (1988, pi. 2) for the area represented by the 

model, few of the boundaries between subregions correspond to those of the flow systems (fig. 15). Flow-system 

boundaries are drawn along topographic divides 

between basins and are based on water-level gradients 

and estimated flow budgets in each basin. In contrast, the 

deep-flow subregion boundaries are based on the area 

within the lower model layer that contributes horizontal 

flow to model cells having inward flow. Major differences 

are apparent in western Utah, where the northern half of 

the Sevier Lake flow system (number 39 in fig. 15) is part 

of a deep-flow subregion that includes the Great Salt Lake 

Desert and the Great Salt Lake, and in southern Nevada, 

where the Colorado River flow system (number 34 in fig. 

15) is divided into three deep-flow subregions. These 

three deep-flow subregions would have been combined 

as one if the Colorado and Virgin Rivers had been considered to be one discharge area.

The deep-flow subregions are further grouped into five 

deep-flow regions on the basis of areas having simulated 

water levels that generally decline toward one of five 

regional discharge areas. These are named the Death Valley, Colorado River, Bonneville, Railroad Valley, and 

upper Humboldt River regions (fig. 18). The Bonneville 

region is the largest and includes about 39,000 mi in 

western Utah and eastern Nevada, or about 42 percent of 

the total modeled area. The Railroad Valley and upper 

Humboldt River regions are the smallest; each includes 

about 7,200 mi2 or about 8 percent of the modeled area.
A38 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118" 116 114°

42°

40°

38°

36°

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 14. Regional ground-water flow potential. Modified from Harrill (1984, p. 591).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A39

Water budgets for each of the deep-flow regions are summarized in table 5. The listed rates of recharge and discharge are assumed to represent long-term steady-state, 

predevelopment conditions.

The total simulated inflow to the modeled area is about 

1.5 million acre-ft/yr, which corresponds to only 3 percent of the estimated precipitation. About 56 percent of 

this inflow is in the Bonneville region, where precipitation 

in the mountains is generally greater than elsewhere in 

the province. The total simulated inflow does not include 

recharge that is discharged locally within the 37.5-mi2 

area represented by each model cell. Most ground-water 

flow is simulated as shallow flow in the upper model 

layer. Flow is generally from recharge areas in the mountains to adjacent valley lowlands, where it is discharged 

by evapotranspiration, which accounts for 79 percent of 

the simulated discharge from the RASA study area.

In the lower model layer, simulated flow is 428,000 acreft/yr, or only 28 percent of the total inflow. About half of 

this flow is discharged to regional springs as deep flow 

through carbonate rocks. Much of the discharge to 

regional springs is in the Colorado River region, which 

accounts for nearly 46 percent of all regional-spring discharge in the simulation. In this region, simulated discharge to regional springs exceeds evapotranspiration 

(table 5). This contrasts with the upper Humboldt River 

region, where regional-spring discharge is only 3 percent 

of the simulated evapotranspiration.

EXPLANATION 

Carbonate-rock province 

Regional-discharge area

1 Colorado River

2 Great Salt Lake 

O Death Valley 

T1 Carson Sink 

O Walker Lake 

O Pyramid Lake 

f Black Rock Desert

Line of equal regional-flow potential Number is 

altitude, in thousands of feet

Boundary of study area, Great Basin Regional 

Aquifer System

Simulated flow in the lower model layer (deep-flow 

system) is generally southward and northward from a 

large, topographic high in east-central Nevada and southwestern Utah. Southward flow is toward Death Valley 

and the Colorado and Virgin Rivers; northward flow is 

toward the Great Salt Lake Desert and the upper Humboldt River. Within the topographically high area of eastcentral Nevada, some deep ground water flows to a landsurface depression in Railroad Valley.

The model is a simplification of flow through a geologically complex region, in which hydraulic properties can 

change abruptly because of changes in lithology and geologic structure. The sparseness of information on the 

extent of aquifers, their hydraulic properties, and the distribution of water levels precludes developing a model in 

which only one distribution of transmissivity is possible. 

Nevertheless, several general statements can be made 

from the available information and model simulations:

 Most ground-water flow is relatively shallow and 

moves from recharge areas in the mountain 

ranges to discharge areas in adjacent valleys.

 Interbasin movement of ground water to the 

larger regional springs is through permeable carbonate rock in areas where the rock is thick and 

continuous.

 Where carbonate rock is not thick and continuous, consolidated rock beneath the valleys and 

surrounding mountains is not highly transmissive. Thus, apparently not all carbonate rock is 

highly permeable nor are all valleys and surrounding mountains underlain by carbonate 

rock.

 Carbonate rock may be highly transmissive in 

some areas, but the rock is separated from overlying aquifers by poorly permeable consolidated 

rocks and semiconsolidated deposits.

 Only small quantities of deep flow discharge at 

terminal sinks of the Great Salt Lake, the Great 

Salt Lake Desert, the Railroad Valley and Death 

Valley playas, and the Colorado and Virgin Rivers. Instead, deep flow discharges to regional 

springs and areas of evapotranspiration upgradient from the sinks.

 Only small quantities of deep flow are simulated 

in the upper Humboldt River region because 

most of the ground water discharging along the 

river is from local flow associated with the river.
A40 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

120° 118° 116 114°

40° 

38°

36° 

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

EXPLANATION 

Boundary of major flow system Dashed where uncertain

 Boundary of study area, Great Basin Regional Aquifer System

FIGURE 15. Major ground-water flow systems (cross-referenced by number in table 4).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A41

TABLE 4. Selected characteristics of major ground-water flow systems in Great Basin study area

[Major ground-water flow system: See figure 15 and table 1. Area: Includes areas of both basin fill and consolidated rock. Ground-water recharge: Natural recharge 

(excludes irrigation return flows and other man-induced forms of recharge). Ground-water storage: Amount of water (in acre-feet) stored in basin-fill deposits that 

would be released from storage if water table in given area were lowered uniformly 1 foot. Storage for given dewatering interval estimated by multiplying per-foot 

values by total interval (in feet) to be dewatered. Estimated volumes may include some water of poor quality. All estimates from compilation by Harrill and others 

(1988). , minor or negligible]

Number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

Major ground-water flow system

Name

Continental Lake system

Virgin Valley

Swan Lake Valley

Long Valley system

Duck Lake Valley

Black Rock Desert system

Humboldt system

Buffalo Valley

Buena Vista Valley

Granite Springs system

Winnemucca Lake Valley

Truckee system

Lemmon Valley

Cold Spring Valley

Fernley Sink system

Carson system

Walker system

Dixie Valley system

Edwards Creek Valley

Smith Creek Valley

Rawhide Flats

Gabbs Valley

Monte Cristo Valley

South-Central Marshes

Grass Valley

Northern Big Smoky Valley

Diamond Valley system

Death Valley system

Newark Valley system

Railroad Valley system

Penoyer Valley

Independence Valley system

Ruby Valley system

Colorado system

Goshute Valley system

Mesquite Valley

Great Salt Lake Desert system

Great Salt Lake system

Sevier Lake system

Totals

Area 

 (square miles)

400

494

226

729

533

9,100

16,800

504

742

1,300

371

1,700

111

30

356

3,520

3,220

2,380

416

582

227

1,280

284

6,790

595

1,320

3,120

15,800

1,450

4,130

700

1,030

1,280

16,300

3,640

236

18,000

12,900

9,100

140,000

Total number 

of included 

hydrographic 

areas or subareas

2

1

1

4

1

18

34

1

1

2

1

9

3

1

3

7

9

7

1

1

1

1

1

13

1

1

6

30

3

4

1

2

2

35

3

1

20

22

8

262

Ground-water 

recharge 

(acre-feet 

per year)

16,000

7,000

6,700

12,000

9,000

170,000

500,000

12,000

10,000

4,500

2,900

73,000

1,800

900

960

45,000

47,000

15,000

8,000

12,000

150

5,000

500

65,000

12,000

65,000

58,000

98,000

22,000

65,000

4,300

30,000

72,000

200,000

110,000

1,400

370,000

1,380,000

310,000

3,800,000

Ground-water 

storage 

(acre-feet 

per foot)

6,100

420

12,000

5,600

230,000

330,000

17,000

24,000

36,000

9,600

36,000

4,100

450

9,000

110,000

78,000

56,000

7,000

15,000

600

16,000

7,200

190,000

16,000

50,000

88,000

380,000

17,000

92,000

22,000

33,000

43,000

440,000

94,000

7,000

430,000

310,000

310,000

3,500,000
A42 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

FISH SPRINGS FLOW SYSTEM

Interbasin ground-water flow to Fish Springs in western Utah was analyzed using a three-dimensional 

ground-water flow model (Carlton, 1985). At Fish 

Springs, located at the south end of the Great Salt Lake 

Desert in western Utah (fig. 16), ground water discharges 

from carbonate-rock aquifers. Discharge at these springs 

is about 27,000 acre-ft/yr (Bolke and Sumsion, 1978, p. 10) 

and greatly exceeds the estimated recharge in the nearby 

mountains. Gates and Kruer (1981) reported recharge in 

excess of local discharge in basins to the west and south of 

the springs, including Tule, Wah Wah, Pine, and Snake 

Valleys. Simulation of predevelopment steady-state 

ground-water flow in this region was selected herein for 

comparison with the results from the simulation of 

regional ground-water flow in the carbonate-rock province.

The ground-water model of the Fish Springs flow system represents an area of 7,600 mi2. The model is divided 

into a grid of cells each of which represents an area 3 mi 

by 3 mi (about one-quarter the cell size used in the carbonate-rock province model). The grid is oriented in a 

north-south direction (fig. 16), about 10 azimuth degrees 

different from the grid orientation of the carbonate-rock 

province model. One model layer simulates shallow flow 

through basin fill in the valleys and consolidated rock in 

the mountains, and a second model layer simulates deep 

flow through consolidated rock beneath the valleys and 

mountains. Consolidated rocks exposed in the area 

include thick sequences of carbonate rocks and sequences 

of metasedimentary and igneous (plutonic and volcanic) 

rocks. Basin fill and carbonate rock form the principal 

aquifers in the area, whereas noncarbonate consolidated 

rock is considered to form confining units.

COMPARISON OF SIMULATION RESULTS FROM FISH SPRINGS

MODEL AND RESULTS FROM CARBONATE-ROCK PROVINCE

MODEL FOR CORRESPONDING AREA

Ground-water flow as simulated by the Fish Springs 

model was compared to simulations from the carbonaterock province model for the corresponding area. Simulated water budgets, transmissivity distributions, and 

simulated hydraulic heads are the three main types of 

information used in the comparison. This comparison is 

included herein primarily because most future models 

probably will include only parts of the carbonate-rock 

model area. Such a comparison provides an opportunity 

to evaluate problems with boundary conditions that may 

occur when only part of a regional flow system is simulated.

SIMULATED WATER BUDGETS

Simulated water budgets from the Fish Springs and carbonate-rock province models are listed in table 6. Budgets 

from the two models are not comparable in every way 

because orientation of the model grids differs slightly and 

the lateral boundaries are represented differently. In the 

Fish Springs model, the boundaries are generally no-flow, 

assigned-flux, or head-dependent flux boundaries. In the 

carbonate-rock province model, the Fish Springs flow system is one of several internal subsystems. No special conditions are assigned to model cells at the boundary of the 

Fish Springs flow system. If a ground-water divide exists 

because of the distributions of recharge, land-surface altitude, and transmissivity, then no simulated flow crosses 

the boundary. A gradient across the boundary indicates 

subsurface inflow or outflow. To simplify the budget 

shown in table 6, quantities of subsurface inflow and outflow for both models are net values.

Two comparisons were made: One is an overall budget 

that includes both the upper and lower layers of the models, and the other is a budget for just the lower layer. For 

the overall model, the inflow and outflow simulated by 

the Fish Springs model (about 210 ft3 / s) was smaller than 

that simulated by the carbonate-rock province model 

(about 244 ft3 /s) for the same area. The difference was 

only about 16 percent of the inflow and outflow simulated 

by the Fish Springs model. Considering the potential 

errors in available hydrologic information and that the 

models were developed independently, this 16-percent 

difference indicates relatively good agreement. The main

EXPLANATION

Regional-scale model area

Carbonate-rock province 

Fish Springs flow system

Model area of basin-fill aquifer, by hydrographic 

area

@© Paradise Valley

U©©[D Stagecoach Valley

H ©H) Carson Valley

 fl ©4J Smith Creek Valley

g©£} Milford Area

Boundary of study area, Great Basin Regional 

Aquifer System

Spring
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A43

120° 118° 116° 114° 112°

42°

40°

38°

36°

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 16. Representative basins, by hydrographic area or subarea (fig. 2, table 1), and regional systems that were used to model ground-water

flow in Great Basin Regional Aquifer-System Analysis.
A44 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

118° 116° 114° 112° 110°

42°

EXPLANATION

High-transmissivity zone Shows area where 

estimated transmissivities in lower layer exceed 

0.006 square feet per second

- - Boundary of central corridor of thick carbonate 

rocks Approximately located. Queried where 

not further delinated. Modified from Dettinger 

(1989a, p. 14)

Boundary of carbonate-rock province model

 Boundary of study area, Great Basin Regional 

Aquifer System

Spring used in model simulations

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30'. central meridian -114C00'

FIGURE 17. High transmissivity in lower model layer (carbonate-rock aquifers) in relation to springs used in model simulations and to boundary of 

central corridor of thick carbonate rocks in south-central Nevada. Area of figure is same as for figure 8.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A45

118° 116° 114° 112° 110°

UPPER

HUMBOLDT

REGION

RAILROAD 

VALLEY 

REGION

fDEATFJl 

VALLEY 

REGION

EXPLANATION 

Boundary of carbonate-rock province model

38'

36° -

 Boundary of study area, Great Basin Regional 

Aquifer System

 Boundary of flow region in lower model layerApproximately located

 - - Boundary of flow subregion in lower model layerApproximately located

 2000 Potentiometric contour-Shows altitude at simulated 

ground-water level in lower model layer. Contour 

interval 1,000 feet. Hachures indicate depression

^^- Generalized direction of deep ground-water flow 

Spring used in model simulation

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000, 1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 18. Deep-flow regions and subregions in carbonate-rock aquifers (lower model layer) based on simulated hydraulic heads. Area of figure

same as for figures 8 and 17. Modified after Prudic and others (1995, p. D51).
A46 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 5. Simulated predevelopment ground-water flow budgets for five deep-flow regions of carbonate-rock province

[All values are in acre-feet per year (acre-ft/yr), rounded to nearest 1,000. Modified from Prudic and others (1995)]

Deep-flow regions

Budget component and 

model layer(s) involved

Death 

Valley 

region

Colorado 

River 

region

Bonneville 

region

Railroad 

Valley 

region

Upper 

Humboldt 

River region

Entire 

modeled 

area

Inflow

Mountain recharge (upper layer)

Subsurface inflow from adjacent 

region (both upper and lower 

layers).

Leakage (upper layer) 

Total

161,000

46,000

0

177,000

202,000

25,000

0

207,000

855,000

334,000

0

889,000

132,000

42,000

0

134,000

174,000

512,000

73,000

189,000

1,524,000

( 6 )

3,000

61,527,000

Outflow

Evapotranspiration8 (upper layer)

Regional springs (lower layer)

Subsurface outflow to adjacent 

regions (both upper and lower 

layers).

Leakage (upper layer) 

Total

147,000

22,000

93,000

148,000

180,000

91,000

97,000

1010,000

157,000

205,000

758,000

64,000

n8,000

1659,000

889,000

86,000

24,000

1223,000

0

133,000

131,000

4,000

1325,000

1728,000

188,000

1,213,000

211,000

( 6 )

102,000

61,526,000

Comprises 8,000 acre-ft/yr from Colorado River region and 8,000 acre-ft/yr from Railroad Valley region.

Comprises 2,000 acre-ft/yr from Bonneville region, 1,000 acre-ft/yr from Railroad Valley region, and 2,000 acre-ft/yr from Death Valley region.

Comprises 4,000 acre-ft/yr from Railroad Valley region, 25,000 acre-ft/yr from upper Humboldt River region, and 5,000 acre-ft/yr from Colorado River region. 

4 Entirely from Bonneville region.

Comprises 10,000 acre-ft/yr from Railroad Valley region, 1,400 acre-ft/yr from Death Valley region, and 600 acre-ft/yr from Bonneville region.

Net flow among regions within modeled area is zero. 

7 From Humboldt River and selected tributaries.

Includes evapotranspiration of flow from small springs that are assumed to be discharging from upper layer; does not include evapotranspiration from regional 

springs that are simulated to be discharging from lower layer.

Comprises 1,000 acre-ft/yr to upper Humboldt River region and 2,000 acre-ft/yr to Colorado River region.

Comprises 2,000 acre-ft/yr to Bonneville region and 8,000 acre-ft/yr to Death Valley region.

Comprises 5,000 acre-ft/yr to Colorado River region, 2,000 acre-ft/yr to Railroad Valley region, and 1,000 acre-ft/yr to upper Humboldt River region.

Comprises 8,000 acre-ft/yr to Death Valley region, 10,000 acre-ft/yr to upper Humboldt River region, 4,000 acre-ft/yr to Bonneville region, and 1,000 acre-ft/yr 

to Colorado River region.

Entirely to Bonneville region.

Entirely to Death Valley playa, ultimately consumed by evapotranspiration.

Comprises 5,000 acre-ft/yr to Virgin River and 2,000 acre-ft/yr to Lake Mead and Colorado River.

Comprises 34,000 acre-ft/yr to Sevier River and Sevier Lake, 22.000 acre-ft/yr to Utah Lake, and 3,000 acre-ft/yr to Great Salt Lake.

17 To Humboldt River and selected tributaries.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A47

TABLE 6. Predevelopment ground-water budgets from Fish Springs ground-water flow model and from 

carbonate-rock province ground-water flow model for comparable area

[All values are listed in cubic feet per second, which are the units used in the models, and are reported to two decimal places to 

allow for comparisons of small differences between model estimates]

Ground-water budgets

(cubic feet per second)

Carbonate-rock province model Fish Springs model

Upper and lower model layers

Inflow:

Constant head

Constant fluxes1

Springs2

Recharge

Evapotranspiration

Head-dependent boundaries

Subsurface inflow (net)

Total

Outflow:

Constant head

Constant fluxes1

Springs2

Recharge

Evapotranspiration

Head-dependent boundaries

Subsurface outflow (net)

Total

0.00

.00

.00

243.89

.00

.00

.00

243.89

0.00

.00

41.01

.00

155.82

15.76

31.32

243.91

0.00

8.90

.00

198.22

.00

2.84

.00

209.96

0.00

9.66

39.02

.00

161.76

.00

.00

210.44

Lower model layer

Inflow:

Constant head

Constant fluxes1

Springs2

Recharge

Evapotranspiration

Head-dependent boundaries

Inflow from top layer (net)

Subsurface inflow (net)

Total

Outflow:

Constant head

Constant fluxes1

Springs2

Recharge

Evapotranspiration

Head-dependent boundaries

Outflow to top layer (net)

Subsurface outflow (net)

Total

0.00

.00

.00

.00

.00

.00

38.42

2.59

41.01

0.00

.00

41.01

.00

.00

.00

.00

.00

41.01

0.00

5.52

.00

.00

.00

2.76

30.24

.00

38.52

0.00

.00

39.12

.00

.00

.00

.00

.00

39.12

Assigned values simulated by well functions. 

2 Values simulated by drain functions.
A48 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

differences are that in the carbonate-rock province model 

a larger value of recharge was assigned, and in the Fish 

Springs model this was not fully offset by inflow from 

head-dependent boundaries and some assigned recharge 

(simulated as inflow from wells). The difference in simulated evapotranspiration was only about 4 percent. However, the smaller grid size of the Fish Springs model 

allowed a more refined depiction of the simulated area of 

evapotranspiration. Simulated outflow differed primarily 

in that the carbonate-rock model allowed for a net subsurface outflow of about 31 ft3 /s, whereas the Fish Springs 

model simulated none. However, the carbonate-rock 

model simulated the combined net outflow from headdependent boundaries and subsurface outflow as about 

47 ft3 / s. In contrast, the Fish Springs model simulated no 

net subsurface outflow from head-dependent boundaries 

and only about 10 ft3 /s net subsurface outflow as discharge from wells (assuming constant fluxes). Thus, the 

larger amount of inflow simulated in the corresponding 

area of the carbonate-rock model is discharged primarily 

by subsurface outflow.

For the lower model layer, the inflow and outflow simulated by the carbonate-rock model (about 41 ft3 /s) was 

larger than that simulated by the Fish Springs model 

(about 39 ft3 /s). The difference was only about 5 percent. 

This agreement is close because in both models the outflow represents only discharge from Fish Springs. Simulated inflow to the lower layer consisted primarily of 

downward leakage from the upper layer in both models. 

The carbonate-rock model simulated some additional net 

subsurface inflow, and the Fish Springs model simulated 

some additional subsurface inflow (simulated by wells 

and head-dependent boundaries).

The budgets for the carbonate-rock and Fish Springs 

ground-water flow models are similar in many aspects. 

Most of the differences noted are due to differences in 

assigned conditions at the boundary of the Fish Springs 

model as contrasted to calculated flows along the Fish 

Springs model boundary in the carbonate-rock model.

TRANSMISSIVITY DISTRIBUTIONS

Transmissivity distributions in the lower layer of the 

Fish Springs and carbonate-rock province models are 

shown in figure 19. Transmissivity values in the lower 

layer of each model are not strictly comparable because 

simulating anisotropic conditions in the lower layer of the 

Fish Springs model resulted in an improved fit of the 

hydraulic-head data used for calibration. The best fit was 

obtained when transmissivity in the north-south direction was greater than transmissivity in the east-west 

direction by factor of 1.5 (Carlton, 1985, p. 76). The northsouth direction was used for the lower layer of the Fish 

Springs model (fig. 19A) because that direction better parallels regional flow. Isotropic values of transmissivity 

were used in the carbonate-rock province model (fig. 

19B).

Transmissivity distributions from the Fish Springs and 

the carbonate-rock province models show similar areas of 

relatively high and low values. However, values for the 

lower layer of the Fish Springs model are generally larger 

than the values for the lower layer of the carbonate-rock 

province model. The larger values are due in part to the 

previously discussed factor of directional anisotropy in 

the Fish Springs model. They are also due to the fact that 

simulated subsurface inflow and outflow across the Fish 

Springs flow-system boundary in the carbonate-rock 

province model produced a higher flux in the lower layer. 

This allowed the observed hydraulic-head distribution to 

be matched by using lower values of transmissivity.

The most significant similarity between the two transmissivity distributions is that both indicate an area of 

high transmissivity beneath parts of Tule Valley and the 

House Range. In the carbonate-rock model the area of 

highest transmissivity is offset slightly to the west and lies 

principally beneath Tule Valley. However, both models 

support the conclusion that the House Range and parts of 

adjacent Tule Valley act as a regional subsurface drain that 

transports water north to Fish Springs and adjacent discharge areas.

SIMULATED HYDRAULIC HEADS

Simulated hydraulic heads in the upper and lower layers of the Fish Springs and carbonate-rock province models indicate the same general pattern of ground-water 

flow. Ground water flows from recharge areas that are 

along the southwest boundary of the modeled area northward and eastward toward the regional discharge area in 

Fish Springs Flat at the northeast corner of the modeled 

area. However, the two models also differ significantly. 

For example, water-level contours simulated for the 

upper layer (basin-fill deposits) in the eastern and southern parts of the modeled area (Sevier Desert, Wah Wah 

Valley, Pine Valley, and southern Snake Valley) are consistently higher in the carbonate-rock province model than 

in the Fish Springs model (fig. 20A). Moreover, contours 

of heads simulated by the carbonate-rock model indicate 

subsurface inflow along the southeast boundary of the 

modeled area and contours simulated by the Fish Springs 

model indicate little inflow along this boundary.

Simulated hydraulic heads in the lower layer of the two 

models (fig. 20B) show the same general differences as 

previously discussed regarding the upper model layer. In 

the lower layer, heads simulated by the carbonate-rock 

province model are higher than heads simulated by the 

Fish Springs model throughout almost all the area represented by the Fish Springs model.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A49

Differences in the simulated hydraulic heads are attributed primarily to differences in simulated subsurface 

inflow and outflow at the boundary of the Fish Springs 

model area. Also, transmissivity values used in the carbonate-rock province model are lower than those used in 

the Fish Springs model. This difference caused the carbonate-rock province model to simulate higher heads, 

assuming similar fluxes for the two models.

SIMULATION OF GROUND-WATER FLOW IN BASIN-FILL 

AQUIFERS

The Great Basin RASA study area includes 260 hydrographic areas. Most contain a basin-fill aquifer and 

include the drainage area of adjacent mountains. Because 

not all basin-fill aquifers could be modeled, the approach 

taken was to model selected areas that represent the large 

range of conditions across the study area. The five hydrographic areas that were selected (fig. 16) are the Milford 

Area in Utah and Carson, Paradise, Smith Creek, and 

Stagecoach Valleys in Nevada (Thomas, Carlton, and 

Mines, 1989; Harrill and Preissler, 1994; Prudic and Wood, 

1995; Prudic and Herman, 1996; Mason, 1998). In general, 

the Milford area represents a large basin-fill reservoir 

under sustained development; Carson Valley represents a 

basin-fill aquifer dominated by a through-flowing river; 

Paradise Valley represents a basin-fill reservoir having an 

upgradient part dominated by streams and an arid lower 

part; Smith Creek Valley represents a topographically 

closed, arid basin; and Stagecoach Valley represents a 

small, topographically closed basin that is partly drained 

by subsurface outflow.

Each basin-fill aquifer was simulated by using the 

USGS finite-difference ground-water flow model developed by McDonald and Harbaugh (1988). In each valley, 

the basin-fill aquifer was modeled as a three-dimensional 

system composed of two or three layers (fig. 21). This concept can be applied to many parts of the Great Basin, 

although, depending on specific conditions, use of fewer 

than or more than the three layers shown in figure 216 

may be desirable. Selected characteristics and hydraulic 

properties of the five basin-fill aquifer models are listed in 

table 7.

Each model was used to simulate several hypothetical 

development scenarios that illustrate effects of variations 

in pumping rate, location of pumping, and the degree to 

which pumping was concentrated. Pumping rates were 

normalized in terms of the simulated steady-state (predevelopment or natural) recharge to and discharge from 

each basin-fill aquifer.

Rates equal to or twice the simulated steady-state 

recharge and discharge were used to simulate the development scenarios. Pumping location was approximately 

standardized relative to areas of natural discharge. The

degree to which pumping was concentrated was simulated by either distributing the pumping locations or concentrating the pumping at one location.

Standard scenarios using selected combinations of the 

above factors were run with each of the five models. 

Because the objective was to illustrate the long-term 

response to pumping, the modeled systems were stressed 

for simulated 300-yr periods and then allowed to recover 

for 300 yr. Shorter pumping periods were used in several 

of the model runs for scenarios where concentrated 

pumping caused large drawdowns. One scenario 

involved variable pumping. In that scenario, the modeled 

systems were stressed for 50 yr at twice the rate of 

recharge and discharge and then pumping was reduced 

to a rate equal to the steady-state recharge and discharge 

and the simulation was continued for another 250 yr.

Simulated responses of the five models to the scenario 

in which pumping equals the steady-state recharge and 

discharge and wells are distributed strategically to capture discharge are compared in table 8. In all five models 

the long-term maximum water-level declines were minimal (ranging from 20 to 99 ft) and a new equilibrium was 

either approached or attained by the end of the 300-yr 

pumping period. The results of this scenario suggest that 

if pumping is located strategically with respect to areas of 

natural discharge, then management of basins on the 

basis of a sustained-yield concept may be a viable option. 

If pumping is not located strategically with respect to discharge or is highly concentrated, the sustained-yield concept may not be viable because excessive drawdowns 

may occur before all natural discharge is captured.

Simulated responses of the five models to other scenarios indicated that location of pumping and the degree to 

which pumping is concentrated are factors that can be as 

significant as the overall pumping rate in determining the 

response to development by pumping. Also, the location 

of pumping with respect to streams and rivers in hydraulic continuity with the ground-water system is important 

in determining the response to pumping.

The long-term drawdowns for the scenarios in which a 

variable pumping rate was used were about the same as 

for scenarios with similar distributions of pumping held 

equal to the steady-state recharge and discharge for the 

entire 300-yr pumping period. This scenario illustrated 

the feasibility of managing basins under an optimal-yield 

concept, by which the overall pumping rate was allowed 

to exceed the steady-state recharge and discharge for a 

short period of time instead of being limited to the steadystate recharge and discharge throughout the entire period 

of pumping.
A50 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

114° 113°

38'

EXPLANATION 

Basin fill

Consolidated rock

Transmissivity, in feet squared 

per second

 Boundary of Fish Springs

ground-water flow system

 Boundary of active cells in 

Fish Springs model

> Spring

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 19. Transmissivity in lower layers of ground-water flow models. A Fish Springs flow system (Carlton, 1985). B, Carbonate-rock

province (Prudic and others, 1995).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A51

114° 113°

39

38
A52 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN. NEVADA-UTAH

114° 113°

38'

EXPLANATION 

Basin fill 

Consolidated rock

Water-altitude contour 

Simulated by Fish Springs 

ground-water flow model 

(Carlton. 1985, p. 72). 

Interval 500 feet above 

4,500-foot altitude and 100 

feet below 4,500-foot altitude. Datum is sea level

Water-altitude contour 

Simulated by carbonaterock province ground-water 

flow model (Prudic and 

others, 1995, p. D36). 

Interval 500 feet above 

4,500-foot altitude and 100 

feet below 4,500-foot altitude. Datum is sea level. 

Hachures indicate depression

Boundary of Fish Springs 

ground-water flow model

Base from U.S. Geological Survey digital data, 1:100,000,1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 20. Simulated water-level contours for Fish Springs ground-water flow system and for comparable area of carbonate-rock province 

Geographic area is same as for figure 19. A, Upper model layer. B, Lower model layer.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A53

114° 113°

40°

38'
A54 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN NEVADA-UTAH

Recharge PumPed Flo n9 

wells wells wells

B

DC

Q

Z

=>

O

m

|

_ i

LL

6

z

1 1

1

Recharge r *> r

Mil ' '

1

 * * 1 1 1

Lateral

flow

Leakage .

-o- Evapotranspiration Recharge

t t t t t t t t t \ \

MODEL LAYER 1: SHALLOW UNCONFINED ZONE

Model simulates thickness, specific yield, recharge,

transmissivity, and evapotranspiration.

Leakage

t t t f _________________

MODEL LAYER 2: CONFINED AQUIFER

Model simulates storage coefficient and transmissivity. Inflow from permeable rock simulated

as recharge wells. Pumped and flowing wells

simulated as discharge wells.

4

* * Leakage MODEL LAYER 3: CONFINED AQUIFER

f Lateral

flow

Poorly defined. Layer may include permeable

rock. Model simulates storage coefficient,

transmissivity, and lateral recharge. Recharge

simulated as recharge wells.

DC

Q

z

0

CD

O_l

LL

6

z

NO-FLOW BOUNDARY

FIGURE 21. Basin-fill aquifer. A Generalized hydrogeologic section. B, Layers simulated by three-dimensional finite-difference model to

represent flow system in aquifer.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A55

TABLE 7. Selected characteristics and hydraulic properties of five basin-fill aquifer models used in this study

[>, greater than. %, percent. , not applicable or no data]

Milford area1 Carson Valley Paradise Valley Smith Creek Valley Stagecoach Valley

Area, in square miles

Basin area

Area represented by active 

model cells.

1,160

589

444 >bOO

171 325

583

228

70

30.1

Model characteristics

Hydrologic regimen

Total number of layers

Large, partly drained, 

arid basin.

3

Drained basin, river- Tributary area of 

reach segment of Humboldt River. 

Carson River. Stream-dominated

River dominated. upper valley, arid 

lower valley.

2 3

Topographically 

and hydrologically 

closed basin.

3

Topographically closed, 

small, partly drained 

basin.

3

Hydraulic conductivity, in feet per second

Horizontal, top layer:

Maximum

Geometric mean

Minimum

Vertical, between layers 1 and 2:

Maximum

Geometric mean

Minimum

0.00069

.000097

.000019

0.000018

.0000069

.00000014

0.0068 0.00027

.00025 .00009

.000008 .000008

0.000055 0.0000049

.0000009 .0000014

.000000004 .00000013

0.00025

.000043

.000002

0.0000245

.00000113

.00000000125

0.001

.0002

.00005

0.00000072

.00000014

.00000026

Specific yield, in percent

Maximum

Median

Minimum

21.9

20.1

19.9

37.5 22.5

21.2 13.5

4.6 5.4

15

10

2

12

12

.7

Flux, in cubic feet per second

Total flux

Layer 1 flux (and percentage 

of total flux).

Layer 2 flux (and percentage 

of total flux).

Layer 3 flux (and percentage 

of total flux).

60.0

55.1 

(92%)

54.6 

(91%)

9.9 

(16%)

285.7 127.8

285.7 127.8 

(100%) (100%)

27.7 5.1 

(9.7%) (4.0%)

 1.2 

(.9%)

11.0

11.0 

(100%)

10.5 

(95%)

5.6 

(51%)

1.27

1.27 

(100%)

.53 

(42%)

.23 

(18%)

Inflow, in percent

Recharge

Subsurface inflow

Inflow from river or stream

62.7

32.8

4.4

49.1 9.1

 

50.9 90.8

100.0 59.7

40.3

Outflow, in percent

Evapotranspiration

Subsurface inflow

Outflow to river or stream

Other

62.0

11.5

26.5

71.9 99.4

 

28.1 .6

 

100.0 69.3

18.0

12.7

1Hydrographic area 284 (see fig. 2 and table 1).
A56 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

TABLE 8. Simulated responses to pumping scenario where pumping equals estimated natural recharge and discharge and is distributed strategically

to capture discharge

[do. or Do., ditto]

Pumping Maximum ,, , .. . j i n

f & . . . _nri ,. Cumulative storage deplenori

rate water-level Recovery 300 years after ,, .... . ,. onr. °c .

. , . .I-. j £ New equilibrium after 300 years of pumping (acre-feet decline in cell end of pumping n / , .f

v f f t> (arrp-fppH

per year) (feet) (acre-feet)

Paradise Valley 72,000 99

Smith Creek Valley 8,000 20

Stagecoach Valley 920 28

.do................... Approached

.do. 

.do..

Attained 

.......do.....

Principal source of water 

after 300 years of pumping

Milford area 

Carson Valley

43,400 

100,000

60

45

Almost complete 

Complete

Approached 

Attained

2,555,000 

160,000

Reduction in evapotranspiration.

Decreased seepage to 

and increased leakage 

from Carson River and 

from ditches.

1,000,000 Reduction in evapotranspiration.

2,200,000 .......Do.........................

26,000 .......Do.........................

Model area or hydrographic area (see fig. 2 and table 1).

WATER QUALITY AND GEOCHEMISTRY

Water in the principal aquifers of the Great Basin contains generally less than 1,000 mg/L dissolved solids 

except in natural-discharge and geothermal areas. Aquifers in industrial, mining, urbanized, and agricultural 

areas and aquifers containing highly soluble evaporative 

salts and other less soluble minerals also may have dissolved-solids concentrations greater than 1,000 mg/L, or 

elevated concentrations of undesirable constituents, or 

both. The general distribution of areas where the dissolved-solids concentration exceeds 1,000 mg/L is shown 

in figure 22.

The dissolved solids in water in basin-fill aquifers of the 

western Great Basin generally are dominated by sodium, 

calcium, and bicarbonate; in basin-fill aquifers of the eastern Great Basin by calcium, sodium, magnesium, and 

bicarbonate; and in carbonate-rock aquifers of the eastern 

Great Basin by calcium, magnesium, and bicarbonate. 

The dissolved solids in water concentrated by evapotranspiration in discharge areas generally are dominated 

by sodium, chloride, and sulfate.

Described in the next two sections are the geochemical 

and hydrologic processes responsible for the major-ion 

chemistry and isotopic composition of water in aquifers 

throughout the Great Basin for representative examples 

of the two principal types of flow systems in the Great 

Basin: a hydrologically closed basin-fill aquifer in Smith 

Creek Valley (west-central Nevada) and a regional carbonate-rock aquifer system (southern Nevada).

SMITH CREEK VALLEY BASIN-FILL AQUIFER

Chemical and isotopic compositions of water in the 

basin-fill aquifer in Smith Creek Valley (fig. 23; Thomas 

and others, 1996) evolve because of (1) evapotranspirative 

concentration of the water, (2) dissolution of minerals and 

soil-zone carbon dioxide gas, (3) precipitation of minerals 

or formation of minerals by incongruent dissolution, and 

(4) ion exchange. Recharge originates mainly as precipitation in the surrounding Desatoya and Shoshone Mountains and New Pass Range. Solutes in this precipitation 

are concentrated by evapotranspiration. The water then 

infiltrates the soil zone and obtains additional ions by dissolving carbon dioxide gas and volcanic rock (groundmass and phenocrysts, dominantly plagioclase feldspar) 

and thus produces a sodium-calcium bicarbonate water. 

In addition, small amounts of alkali feldspar, gypsum, 

biotite, and possibly pyrite, illite, and chlorite are dissolved, each adding ions to the water. Chalcedony precipitates and thus removes ions from the water, and kaolinite 

(or some other clay mineral) forms as the result of incongruent dissolution of the feldspars.

EXPLANATION

| | Total dissolved solids greater than 1,000 milligrams 

per liter

 Boundary of study area, Great Basin Regional 

Aquifer System
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A57

120° 118° 116° 114° 112°

42°

40°

38°

36°

Base from U.S. Geological Survey digital data, 1:100,000, 1978-88, and 1:250,000,1987

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30', central meridian -114°00'

FIGURE 22. Areas where dissolved-solids concentration in water from principal aquifers in Great Basin study area exceeds 1,000 milligrams per liter.

Modified after J.M. Thomas (written commun., 1995).
A58 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

117°45' 117°30'

39°30'

39°15'

39°00

5 KILOMETERS

Base from U.S. Geological Survey, 1:100,000,

Smith Creek Valley, 1975

Universal Transverse Mercator projection

EXPLANATION 

Basin fill

Consolidated rock 

Playa deposits 

Phreatophytes

Smith Creek Valley Hydrographic Area 

boundary

Ground-water divide Approximately located

FIGURE 23. Location and general hydrologic features of 

Smith Creek Valley Hydrographic Area. Modified from 

Thomas and others (1996)

Calcium and magnesium in the water exchange for 

sodium in clays in the playa area, where basin-fill deposits grade from coarser to finer grained sediments. This ion 

exchange results in the sodium-calcium bicarbonate 

water evolving into a sodium bicarbonate water. Calcium 

also may be removed from the water by the weathering of 

plagioclase to Ca/Na-montmorillonite and the precipitation of a zeolite mineral.

Evapotranspiration, dissolution of chloride-containing 

evaporative salts, and precipitation of calcite and zeolite 

minerals are the main processes affecting ground-water 

chemistry in the discharge area. These processes result in 

the evolution of sodium bicarbonate water into a sodium 

chloride water. Constituents also are added by dissolution of plagioclase and alkali feldspars, gypsum (or other 

sulfate-containing evaporative salts), and chlorite, 

whereas kaolinite is formed by incongruent dissolution. 

Evapotranspiration of shallow ground water in the 

discharge area causes proportions of the isotopes deuterium and oxygen-18 to increase relative to those of 

hydrogen-1 and oxygen-16, respectively.

CARBONATE-ROCK AQUIFERS OF SOUTHERN NEVADA

Chemical and isotopic compositions of water in the carbonate-rock aquifers of southern Nevada (Thomas and 

others, 1996) evolve because of (1) dissolution of minerals 

and soil-zone carbon dioxide gas, (2) precipitation or formation of minerals, (3) ion exchange, (4) mixing of chemically or isotopically different waters, and (5) geothermal 

heating. Recharge originates primarily as precipitation in 

the Spring Mountains and Sheep Range (fig. 15). Solutes 

in this precipitation are concentrated by evapotranspiration. The water then infiltrates the soil zone and obtains 

additional ions by dissolving carbon dioxide gas, calcite, 

and dolomite. Recharge waters generally are saturated 

with respect to both calcite and dolomite and contain predominantly calcium, magnesium, and bicarbonate. These 

waters then circulate to depths sufficient to be affected by 

geothermal heating, which precipitates calcite.

Throughout the carbonate-rock aquifers, the following 

geochemical processes occur: dedolomitization (dissolution of gypsum, which causes dolomite to dissolve and 

calcite to precipitate), exchange of calcium and magnesium in the water for sodium in clays; precipitation of 

chalcedony; formation of kaolinite; and, in some spring 

areas, exsolution of carbon dioxide gas. In addition, 

sodium and potassium probably are added to the water 

by the dissolution of volcanic rock (glass and minerals, 

dominantly sodic plagioclase and alkali feldspar) and of
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A59

zeolite minerals (probably clinoptilolite), which are 

present in parts of the study area. Locally, calcium, 

sodium, sulfate, and chloride are added by dissolution of 

gypsum and halite. In the Ash Meadows flow system, a 

subsystem of the Death Valley ground-water flow system 

(fig. 15), downward leakage of water dissolves sodium 

and sulfate from the overlying fine-grained basin fill and 

volcanic-rock confining unit. As a result, sodium and sulfate concentrations increase in the carbonate-rock aquifers. Thus, outside the recharge areas of the carbonaterock aquifers in southern Nevada, sodium, sulfate, and 

chloride can be major constituents dissolved in the water.

Waters from different areas have different chemical and 

isotopic compositions. The mixing of these waters in the 

carbonate-rock aquifers can result in water that is chemically and isotopically different from the source waters. 

However, all the mixed waters generally are undergoing 

the same geochemical processes, which result in waters of 

similar chemical composition in the carbonate-rock aquifers irrespective of source. Thus, the modified isotopic 

composition of the mixed water, as compared to the mixing (source) waters, is the primary evidence of mixing in 

the carbonate-rock aquifers.

The isotopic and chemical compositions of waters were 

used to delineate ground-water flow paths in the carbonate-rock aquifers of southern Nevada (fig. 24; Thomas and 

others, 1996). First, the deuterium content of water in the 

carbonate-rock aquifer was used to determine source 

areas, flow paths, and mixing. Second, these deuteriumdelineated flow paths and mixing patterns were checked 

for chemical feasibility by using mass-balance and mineral-equilibrium models based on water chemistry and 

geochemical processes that are assumed to have produced the chemical composition of the water. Third, 

adjusted carbon-14 ages were determined from carbonisotope data on the basis of the mass-balance reaction 

models. These ages provide another check on the flow 

path and mixing patterns because ground-water ages 

must increase down flow paths or must change due to 

mixing of different-age waters.

These isotopic and geochemical models produced the 

following results (see figs. 15 and 24; listed flow quantities 

are rounded off to the nearest 1,000 acre feet):

(1) Ground water discharging at Muddy River 

springs (the terminus of the White River flow system, which is a subsystem of the Colorado River 

ground-water flow system) is a mixture of 40 percent (14,000 acre-ft/yr) from Pahranagat Valley 38 

percent (14,000 acre-ft/yr) from the Sheep Range, 

and 22 percent (8,000 acre-ft/yr) from the southern 

Meadow Valley Wash.

(2) Ground water discharging at the terminus of the 

Ash Meadows flow system (Ash Meadows 

springs) is a mixture of 60 percent (10,000 acreft/yr) from the Spring Mountains and 40 percent 

(7,000 acre-ft/yr) from Pahranagat Valley

(3) Almost all ground water in Las Vegas Valley 

comes from recharge in the Spring Mountains. 

(The Sheep Range may supply 2,500 acre-ft/yr or 

less to northern Las Vegas Valley)

(4) All ground water in Pahrump Valley comes from

recharge in the Spring Mountains. 

Flow velocities calculated from adjusted carbon-14 

ages are less than velocities calculated from hydrologic 

data. These differences are summarized for areas studied 

by Thomas and others (1996) in table 9. This discrepancy 

in velocities indicates that the ages or average hydraulic 

conductivity may be overestimated, or the effective 

porosity and horizontal-flow path lengths may be underestimated, or both. Ground-water ages are sensitive to the 

carbon-13 composition of the dissolving calcite. Thus the 

ages could be overestimated if more vein calcite, which 

has lighter carbon-13 composition than the primary calcite, is exchanging carbon with the water than the 50 percent assumed for determining ages for flow-velocity 

estimates. However, age-calculated flow velocities, 9.6 to 

144 ft/yr, are in the range of velocities simulated for the 

Madison aquifer in Montana, Wyoming, and South 

Dakota (Downey 1984). The Madison aquifer is a carbonate-rock aquifer similar to the carbonate-rock aquifers of 

southern Nevada. The similarity of velocities in the carbonate-rock aquifers in the two different areas indicates 

that the adjusted ages of the ground water are reasonable. 

The large discrepancy in velocities calculated from age 

and hydrologic data for flow from the Spring Mountains 

to adjacent valleys shows the significant lack of knowledge about the recharge process for the carbonate-rock 

aquifers of southern Nevada.
A60 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

116° 115° 114°

38C

'jf^ 1

, ,<r

1 ; '

i

-^A

^K '

fa *

t J

X, > ^

If

1 1

1 > 1

1

1

1

t

*^~ 1 Caliente

* 1 

%

i

!

q ^»j

>

2C

-14,000

r

Beany , 

.v *% ; . *> t*^v/l -^ / / *y : i) ' 1 ^ 

1 * ^

_._

t '" ' 

/ \ t '

v

\

V

\

. - / * - * i r

* ' ; / >,/ *» &

/ .. "* ^\

\

^

\

^

/ r

>/ t< .

vV> 10,000 '«,«. ^r Is* 

* \ .> .?. IT

NEVADA

AREA

\ OF FIGURE

\

\.rM

v m- O> ^ ^

* ^ ^^W *VD LAS«.

V ^ VQ ^ VEGAS ^^

C^^fe^ ^ A ' Q^B * *^

^"v^ *^^ ^^^ f

X^N^/) |^ *

^fC-T^ *

</l/>\ 

-T ^v *

^ f

\

\ /

1 % - *

« 

t

>

/ l~

..'"'' ?

t i

uA-1 ,

./ . 

, , .«>*'y""ilxv/'7V^ rf &

(" Lake-^ . /* ^-^ ,// 

y" Mead "v"i«»w^«4 i

!l

N

\

/ ARIZONA ! 

1

^

1

37C

36°

Base from U.S. Geological Survey digital data, 1:100,000,1983 

Universal Transverse Mercator projection 

Zone 11

Geology modified from Winograd and Thordarson (1975),

Jennings (1977), Stewart and Carlson (1978),

and Plume and Carlton (1988)

50 KILOMETERS

FIGURE 24. Ground-water flow (rate and direction) in carbonate-rock aquifers of southern Nevada. Modified from Prudic and others

(1995, p. D52) and Thomas and others (1996, p. 40).
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A61

TABLE 9. Flow velocities in carbonate-rock aquifers, southern Nevada, calculated from adjusted carbon-14 ages and hydrologic data

[Modified from Thomas and others (1996, p. C61)]

Flow path Traveltime1 

(years)

Horizontal 

flow-path 

distance 

(miles)

Changes in 

hydraulic 

head2 

(feet)

Hydraulic

(feet per mile) Based on 

carbon 14 aj

Flow velocity 

(feet per year)

Based or 

;es3 hydrologic data

White River flow system

Coyote Spring Valley to Muddy River springs 

Sheep Range to Muddy River springs 

Pahranagat Valley to Coyote Spring Valley 

Meadow Valley Wash to Coyote Spring Valley

2,700 

5,400 

6,900 

5,700

15 

30 

50 

40

50 

100 

1,800

1,400

3.3 

3.3 

36

35

29 

29

38 

37

50 

50 

540 

520

Ash Meadows flow system

Spring Mountains to Ash Meadows springs 

Pahranagat Valley to Ash Meadows springs

2,200 

5,900

60 

95

1,400 

1,300

23 

14

140 

85

350 

200

Las Vegas Valley

Central part of Spring Mountains to Tule Spring area 

Southern part of Spring Mountains to southwest Las 

Vegas Valley.

6,600 

5,500

15 

10

500 

500

33 

50

12 

9.6

500 

740

Pahrump Valley

Spring Mountains to Pahrump Valley 680 10 500 50 78 740

Adjusted carbon-14 traveltime between two samples along flow path, or for two mixing waters; for mixing waters, traveltime depends on hydraulic gradients 

of two separate flow paths.

Differences in water level between source area and end of flow path. Head difference in Spring Mountains was calculated assuming that water levels are 500 

feet higher than water levels in wells or springs on adjacent fans rather than by using water levels of apparently perched springs or water levels in wells completed 

in localized areas of alluvium in mountains.

3 Flow velocity was calculated by dividing horizontal flow-path distance by adjusted carbon-14 age.

EXPLANATION 

Basin fill

Consolidated rock

Generalized direction and rate of ground-water flow in 

carbonate-rock aquifers Number is flow rate, in acrefeet per year. Based on deuterium mass-balance mixing 

models

Spring discharging from carbonate-rock aquifer Number 

is discharge, in acre-feet per year

Boundary of central corridor of thick carbonate rocks 

Approximately located

REFERENCES CITED

[Note: Bold type indicates publication produced as part of Great Basin Regional AquiferSystem Analysis.]

Allmendinger. R.W., Hauge. T.A., Mauser. E.C., Potter. C.J.. Klemperer. S.H., 

Nelson, K.D., Kneupfer, P., and Oliver, J., 1987, Overview of the COCORP 

40° N. transect, Western United States The fabric of an erogenic belt: 

Geological Society of America Bulletin, v. 98, p. 308-319.

Allmendinger, R.W., Sharp, J.W., Von Tish, D., Serpa, L., Brown, L., Kaufman, 

S., Oliver, J., and Smith, R.B., 1983, Cenozoic and Mesozoic structure of 

the eastern Basin and Range Province, Utah, from COCORP seismic-reflection data: Geology, v. 11, p. 532-536.

Anderson, R.E., Zoback, M.L., and Thompson, G.A., 1983, Implications of 

selected subsurface data on the structural form and evolution of some basins 

in the northern Basin and Range Province, Nevada and Utah: Geological 

Society of America Bulletin, v. 94. p. 1055-1072.

Anderson, T.W., 1985, Geohydrology of the southwest alluvial basins, Arizona, 

in Anderson, T.W., and Johnson, A.I.. eds., Regional aquifer systems of the 

United States Southwest alluvial basins of Arizona: American Water 

Resources Association Monograph Series, no. 7, p. 99-111.

Anderson, T.W., Freethey, G.W., and Tucci, Patrick, 1992, Geohydrology and 

water resources of alluvial basins in south-central Arizona and parts of adjacent States: U.S. Geological Survey Professional Paper 1406-B, 67 p., 3 pis.

Baker, C.H., 1974, Water resources of the Curlew Valley drainage basin, Utah 

and Idaho: Utah Department of Natural Resources Technical Publication 45, 

91 p.

Bedinger, M.S., Gates, J.S., and Stark, J.R., 1984, Maps showing ground-water 

units and withdrawal, Basin and Range Province, Utah: U.S. Geological 

Survey Water-Resources Investigations Report 83^122-A, 13 p., 1 pi.
A62 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

Bedinger, M.S., Harrill, J.R., and Thomas, J.M., 1984, Maps showing groundwater units and withdrawal, Basin and Range Province, Nevada: U.S. Geological Survey Water-Resources Investigations Report 83^119-A, 10 p., 

2 pis.

Berger, D.L., 1992, Lithologic properties of carbonate-rock aquifers at five test 

wells in the Coyote Spring Valley area, southern Nevada, as determined 

from geophysical logs: U.S. Geological Survey Water-Resources Investigations Report 91^4167, 27 p.

Blankennagel, R.K., and Weir, I.E., Jr., 1973, Geohydrology of the eastern part 

of Pahute Mesa, Nevada Test Site, Nye County, Nevada: U.S. Geological 

Survey Professional Paper 712-B, 35 p.

Bolke, E.L., and Price, Don, 1969, Hydrologic reconnaissance of Curlew Valley, Utah and Idaho: Utah Department of Natural Resources Technical Publication 25, 40 p.

 1972, Hydrologic reconnaissance of the Blue Creek Valley area, Box Elder 

County, Utah: Utah Department of Natural Resources Technical Publication 

37, 38 p.

Bolke, E.L., and Sumsion, C.T., 1978, Hydrologic reconnaissance of the Fish 

Springs Flat area, Tooele, Juab. and Millard Counties, Utah: Utah Department of Natural Resources Technical Publication 64, 30 p.

Bredehoeft, J.D., Back, W, and Hanshaw, B.B., 1982, Regional ground-water 

flow concepts in the United States Historical perspective, in Narasimhan, 

T.N., ed., Recent trends in hydrogeology: Geological Society of America 

Special Paper 189, p. 297-316.

Bunch, R.L., and Harrill, J.R., 1984, Selected hydrologic data from the MX 

missile-siting investigation, east-central Nevada and western Utah: U.S. 

Geological Survey Open-File Report 84-702,123 p.

Burbey, T.J., and Prudic, D.E., 1985, Simulation of regional ground-water 

flow in carbonate-rock aquifers of the Great Basin in Nevada, Utah, 

and adjacent States [abs.]: Geological Society of America Abstracts 

with Programs, v. 17, p. 534.

Campana, M.E., and Boone, R.L., 1986, Hydrologic monitoring of subsurface flow and groundwater recharge in a mountain watershed, in Cold 

Regions Hydrology Symposium, 1986, Proceedings: American Water 

Resources Association, p. 263-273.

Cardinalli, J.L., Roach, L.M., Rush, F.E., and Vasey, B.J., 1968, State of Nevada 

hydrographic areas: Nevada Division of Water Resources map, scale 

1:500,000.

Carey, A.E., 1994, Documentation of model input and output values used 

for analyses of simulated development in Stagecoach Valley, Lyon and 

Storey Counties, western Nevada: U.S. Geological Survey Open-File 

Report 92-630,4 p., 1 diskette.

Carey, A.E., and Prudic, D.E., 1996, Documentation of model input and 

output values for simulation of pumping effects in Paradise Valley, a 

basin tributary to the Humboldt River, Humboldt County, Nevada: 

U.S. Geological Survey Open-File Report 92^191,4 p., 1 diskette.

Carlton, S.M., 1985, Fish Springs multibasm flow system, Nevada and 

Utah: Reno, University of Nevada, Mackay School of Mines M.S. thesis 

no. 1941,103 p.

Carlton, S.M., and Thomas, J.M., 1987, Documentation for a digital computer model of the basin-fill aquifer in Smith Creek Valley, Lander 

County, Nevada: National Technical Information Service Reports PB87-142-899/PB-87-142-907,6 p., 1 magnetic tape.

Carman, R.L., 1985, Estimating evapotranspiration from a phreatophyte 

area in Smith Creek Valley, Nevada [abs.], in Conference on Agricultural and Forest Meteorology, 17th, and on Biometeorology and Aerobiology, 7th, Scottsdale, Ariz., May 1985 [Proceedings]: Boston, 

American Meteorological Society, p. 48.

 1989, Data on evapotranspiration in phreatophyte areas, Smith Creek 

Valley and Carson Desert, west-central Nevada, 1983: National Technical Information Service Reports PB-89-167-407/PB-89-167-399,14 

p., magnetic tape.

 1993, Measurement of evapotranspiration in phreatophyte areas, 

Smith Creek Valley and Carson Desert, west-central Nevada, 1983: 

U.S. Geological Survey Water-Resources Investigations Report 89- 

4118,18 p.

Carpenter, Everett, 1915, Ground water in southeastern Nevada: U.S. Geological Survey Water-Supply Paper 365, 86 p.

Cohen, Philip, 1964, A brief appraisal of the ground-water resources of the 

Grass Valley area, Humboldt and Pershing Counties, Nevada: Nevada 

Department of Conservation and Natural Resources Ground-Water 

Resources Reconnaissance Report 29, 40 p.

Cohen, Philip, and Everett, D.E., 1963, A brief appraisal of the ground-water 

hydrology of the Dixie-Fairview Valley area: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance 

Report 23, 40 p.

Cook, K.L, Montgomery, J.R., Smith, J.T., and Gray, E.F., 1975, Simple Bouguer gravity anomaly map of Utah: Utah Geological and Mineral Survey 

Map 37, scale 1:1,000,000.

Crosthwaite, E.G., 1963, Ground-water appraisal of Antelope and middle Reese 

River Valleys. Lander County, Nevada: Nevada Department of Conservation and Natural Resources Reconnaissance Report 19, 33 p.

Dettinger, M.D., 1989a, Distribution of carbonate-rock aquifers in southern 

Nevada and the potential for their development Summary of findings, 

1985-88: U.S. Geological Survey and Desert Research Institute of the University of Nevada, Program for the Study and Testing of Carbonate-Rock 

Aquifers in Eastern and Southern Nevada Summary Report no. 1, 37 p.

 1989b, Reconnaissance estimates of natural recharge to basins in 

Nevada, U.S.A, by using chloride-balance calculations: Journal of 

Hydrology, v. 106, p. 55-78.

Dettinger, M.D., Harrill, J.R., Schmidt, D.L., and Hess, J.W., 1995, Distribution 

of carbonate-rock aquifers and the potential for their development, southern 

Nevada and parts of Arizona, California, and Utah: U.S. Geological Survey 

Water-Resources Investigations Report 91^1146. 100 p.

Dinwiddie, G.A., and Schroder, L.J., 1971, Summary of hydraulic testing in and 

chemical analyses of water samples from deep exploratory holes in Little 

Fish Lake, Monitor. Hot Creek, and Little Smoky Valleys, Nevada: U.S. 

Geological Survey Report USGS^174-90, 70 p.

Downey, J.S., 1984, Geohydrology of the Madison and associated aquifers in 

parts of Montana, North Dakota, South Dakota, and Wyoming: U.S. Geological Survey Professional Paper 1273-G, 47 p.

Eakin, T.E., 1960, Ground-water appraisal of Newark Valley, White Pine 

County, Nevada: Nevada Department of Conservation and Natural 

Resources Ground-Water Resources Reconnaissance Report 1, 33 p.

 196la, Ground-water appraisal of Long Valley, White Pine and Elko Counties. Nevada: Nevada Department of Conservation and Natural Resources 

Ground-Water Resources Reconnaissance Report 3, 35 p.

 196 Ib, Ground-water appraisal of Pine Valley, Eureka and Elko Counties, 

Nevada: Nevada Department of Conservation and Natural Resources 

Ground-Water Resources Reconnaissance Report 2, 41 p.

 1962a, Ground-water appraisal of Cave Valley in Lincoln and White Pine 

Counties, Nevada: Nevada Department of Conservation and Natural 

Resources Reconnaissance Report 13, 19 p.

 1962b, Ground-water appraisal of Gabbs Valley, Mineral and Nye Counties, Nevada: Nevada Department of Conservation and Natural Resources 

Reconnaissance Report 9. 27 p.

 1962c, Ground-water appraisal of the Imlay area, Humboldt River Basin, 

Pershing County, Nevada: Nevada Department of Conservation and Natural 

Resources Reconnaissance Report 5, 54 p.

 1963a. Ground-water appraisal of Dry Lake and Delamar Valleys, Lincoln 

and Nye Counties, Nevada: Nevada Department of Conservation and Natural Resources Reconnaissance Report 16, 26 p.

 1963b, Ground-water appraisal of Garden and Coal Valleys, Lincoln and 

Nye Counties, Nevada: Nevada Department of Conservation and Natural 

Resources Reconnaissance Report 18, 29 p.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A63

 1963c, Ground-water appraisal of Pahranagat and Pahroc Valleys, Lincoln 

and Nye Counties, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 21, 36 p.

 1964, Ground-water appraisal of Coyote Spring and Kane Springs Valleys 

and Muddy River springs area, Lincoln and Clark Counties, Nevada: 

Nevada Department of Conservation and Natural Resources Ground-Water 

Resources Reconnaissance Report 25, 40 p.

 1966, A regional interbasin groundwater system in the White River area, 

southeastern Nevada: Water Resources Research, v. 2, no. 2, p. 251-271.

Eakin, T.E., Hughes, J.L., and Moore, D.O., 1967, Water-resources appraisal of 

Steptoe Valley, White Pine and Elko Counties, Nevada: Nevada Department 

of Conservation and Natural Resources Water Resources Reconnaissance 

Report 42, 48 p.

Eakin, T.E., Maxey, G.B., Robinson, T.W, Fredricks, J.C., and Loeltz, O.J., 

1951, Contributions to the hydrology of eastern Nevada: Nevada State 

Engineer Water Resources Bulletin 12, 171 p.

Eakin, T.E., Moore, D.O., and Everett, D.E., 1964, Water-resources appraisal of 

the upper Reese River Valley, Lander and Nye Counties, Nevada: Nevada 

Department of Conservation and Natural Resources Water Resources 

Reconnaissance Report 31, 47 p.

Eakin, T.E., Price, Don, and Harrill, J.R., 1976, Summary appraisals of the 

Nation's ground-water resources Great Basin region: U.S. Geological Survey Professional Paper 813-G, 37 p., 1 pi.

Emme, D.H., 1986, Delineation of subsurface flow in the upper Meadow Valley 

Wash area, southeastern Nevada: Reno, University of Nevada, M.S. thesis, 

90 p.

Everett, D.E., 1964, Ground-water appraisal of Edwards Creek Valley, 

Churchill County, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 26, 18 p.

Everett, D.E., and Rush, F.E., 1964, Ground-water appraisal of Smith Creek and 

lone Valleys, Lander and Nye Counties, Nevada: Nevada Department of 

Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 28, 21 p.

 1965, Water-resources appraisal of Lovelock Valley, Pershing County, 

Nevada: Nevada Department of Conservation and Natural Resources Water 

Resources Reconnaissance Report 32, 40 p.

 1966, A brief appraisal of the water resources of Grass and Carico Lake 

Valleys, Lander and Eureka Counties, Nevada: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 

37, 28 p.

 1967, A brief appraisal of the water resources of the Walker Lake area, Mineral, Lyon, and Churchill Counties, Nevada: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 40, 

44 p.

Fenneman, N.M., and Johnson, D.W, 1946, Physical division of the United 

States: U.S. Geological Survey map, scale 1:7,000,000.

Fiero, G.W, Jr., 1968, Regional ground-water flow systems of central Nevada: 

Reno, University of Nevada Desert Research Institute Miscellaneous 

Report 5, 213 p.

Freeze, A.R, and Witherspoon, PA., 1966, Theoretical analysis of regional 

groundwater flow, Pt. 1, Analytical and numerical solutions to the mathematical model: Water Resources Research, v. 2, no. 4, p. 641-656.

 1967, Theoretical analysis of regional groundwater flow, Pt. 2, Effect of 

water-table configurations and subsurface permeability variation: Water 

Resources Research, v. 3, no. 2, p. 623-634.

Galloway, Devin, 1986, Estimates of confined and unconfmed aquifer characteristics from ground-water level fluctuations induced by Earth tides and 

barometric fluctuations, Yucca Mountain, Nevada [abs.]: Eos (American 

Geophysical Union Transactions), v. 67, no. 44, p. 942.

Gates, J.S., 1984, Hydrogeology of northwestern Utah and adjacent parts 

of Idaho and Nevada: Utah Geological Association Publication 13, p. 

239-248.

Gates, J.S., and Kruer, S.A., 1981, Hydrologic reconnaissance of the southern 

Great Salt Lake Desert and summary of the hydrology of west-central Utah: 

Utah Department of Natural Resources Technical Publication 71, 55 p.

Glancy, P.A., 1968a, Water-resources appraisal of Butte Valley, Elko and White 

Pine Counties, Nevada: Nevada Division of Water Resources Reconnaissance Report 49, 50 p.

 1968b, Water-resources appraisal of Mesquite-Ivanpah Valley area, 

Nevada and California: Nevada Division of Water Resources Reconnaissance Report 46, 57 p.

 1971, Water-resources appraisal of Antelope Valley and East Walker area, 

Nevada and California: Nevada Division of Water Resources Reconnaissance Report 53, 69 p.

 1986, Geohydrology of the basalt and unconsolidated sedimentary aquifers 

in the Fallon area, Churchill County, Nevada: U.S. Geological Survey 

Water-Supply Paper 2263, 62 p.

Glancy, PA., and Katzer, T.L., 1976, Water-resources appraisal of the Carson 

River Basin, western Nevada: Nevada Division of Water Resources Reconnaissance Report 59, 126 p.

Glancy, P.A., and Rush, F.E., 1968, Water-resources appraisal of Smoke CreekSan Emidio Desert area, Nevada and California: Nevada Department of 

Conservation and Natural Resources Water Resources Reconnaissance 

Report 44, 57 p.

Glancy, PA., and Van Denburgh, A.S., 1969, Water-resources appraisal of the 

lower Virgin River valley area, Nevada, Arizona, and Utah: Nevada Division of Water Resources Reconnaissance Report 44, 57 p.

Harrill, J.R., 1968, Hydrologic response to irrigation pumping in Diamond Valley, Eureka and Elko Counties, Nevada, 1959-65, with a section on Surface 

water, by R.D. Lamke: Nevada Department of Conservation and Natural 

Resources Water Resources Bulletin 35, 85 p.

 1969, Hydrologic response to irrigation pumping in Hualapai Flat, Washoe, 

Pershing, and Humboldt Counties, Nevada, 1960-67: Nevada Department 

of Conservation and Natural Resources Water Resources Bulletin 37, 75 p.

 1970, Water-resources appraisal of the Granite Springs Valley area, Pershing, Churchill, and Lyon Counties, Nevada: Nevada Division of Water 

Resources Reconnaissance Report 56, 46 p.

 1971, Water-resources appraisal of the Pilot Creek Valley area, Elko and 

White Pine Counties, Nevada: Nevada Division of Water Resources Reconnaissance Report 56, 46 p.

 1973, Evaluation of the water resources of Lemmon Valley, Washoe 

County, Nevada, with emphasis on effects of ground-water development to 

1971: Nevada Division of Water Resources Bulletin 42, 130 p.

 1984, Great Basin aquifer systems, Nevada-Utah An overview, in 

Repogle, J.A., and Renard, K.G., eds., Specialty Conference on Water 

Today and Tomorrow, Flagstaff, Ariz., July 1984 [Proceedings]: American Society of Civil Engineers Irrigation and Drainage Division, p. 

590-597.

Harrill, J.R., Gates, J.S., and Thomas, J.M., 1988, Major ground-water 

flow systems in the Great Basin region of Nevada, Utah, and adjacent 

States: U.S. Geological Survey Hydrologic Investigations Atlas HA694-C, 2 sheets.

Harrill, J.R., and Hines, L.B., 1995, Estimated natural ground-water 

recharge, discharge, and budget for the Dixie Valley area, west-central 

Nevada: U.S. Geological Survey Water-Resources Investigations 

Report 95-4052,12 p.

Harrill, J.R., and Moore, D.O., 1970, Effects of ground-water development on 

the water regimen of Paradise Valley, Humboldt County, Nevada, 1948-68, 

and hydrologic reconnaissance of the tributary areas: Nevada Division of 

Water Resources Bulletin 39, 123 p.

Harrill, J.R., and Preissler, A.M., 1994, Ground-water flow and simulated 

effects of development in Stagecoach Valley, a small, partly drained 

basin in Lyon and Storey Counties, western Nevada: U.S. Geological 

Survey Professional Paper 1409-H, 74 p.
A64 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

Harrill, J.R., Welch, A.H., and Preissler, A.M., 1984, Hydrogeologic controls on ground-water flow in Stagecoach Valley, Nevada, in vol. 3 of 

Lintz, Joseph, Jr., ed., Western geological excursions [in conjunction 

with 1984 annual meetings of Geological Society of America and affiliated societies]: Reno, University of Nevada, Mackay School of Mines, p. 

117-120.

 1992, Evidence for subsurface inflow to Stagecoach Valley, Lyon 

County, Nevada, in Subitzky, Seymour, ed., Selected papers in the 

hydrological sciences: U.S. Geological Survey Water-Supply Paper 

2340, p.179-192.

Harrill, J.R., Welch, A.H., Prudic, D.E., Thomas, J.M., Carman, R.L., 

Plume, R.W., Gates, J.S., and Mason, J.L., 1983, Aquifer systems in the 

Great Basin region of Nevada, Utah, and adjacent States A study 

plan: U.S. Geological Survey Open-File Report 82-445,49 p.

Hildenbrand, T.G., Kucks, R.P., and Sweeney, R.E., 1983, Digital colored magnetic-anomaly map of the Basin and Range Province: U.S. Geological Survey Open-File Report 83-189, 11 p.

Hines, L.B., 1992, Quantification of natural ground-water evapotranspiration in Smith Creek Valley, Lander County, Nevada, in Subitzky, Seymour, ed., Selected papers in the hydrological sciences: U.S. Geological 

Survey Water-Supply Paper 2340, p. 9-20.

Hintze, L.F., 1963, Geologic map of southwestern Utah: Provo, Utah, Brigham 

Young University Department of Geology, scale 1:250,000.

 1980, Geologic map of Utah: Utah Geological and Mineral Survey, scale 

1:500,000.

Hood, J.W., 1971a, Hydrologic reconnaissance of Hansel Valley and northern 

Rozel Flat, Box Elder County, Utah: Utah Department of Natural Resources 

Technical Publication 33, 41 p.

 1971b, Hydrologic reconnaissance of the Park Valley area, Box Elder 

County, Utah: Utah Department of Natural Resources Technical Publication 

30, 51 p.

Hood, J.W., and Price, Don, 1970, Hydrologic reconnaissance of Grouse Creek 

Valley, Box Elder County, Utah: Utah Department of Natural Resources 

Technical Publication 29, 53 p.

Hood, J.W., Price, Don, and Waddell, K.M., 1969, Hydrologic reconnaissance 

of Rush Valley, Tooele County, Utah: Utah Department of Natural 

Resources Technical Publication 23, 63 p.

Hood, J.W., and Rush, F.E, 1965, Water-resources appraisal of the Snake Valley 

area, Utah and Nevada: Utah State Engineer Technical Publication 14,43 p.

Hood, J.W., and Waddell, K.M., 1969, Hydrologic reconnaissance of Deep 

Creek Valley, Tooele and Juab Counties, Utah, and Elko and White Pine 

Counties, Nevada: Utah Department of Natural Resources Technical Publication 24, 54 p.

Huxel, C.J., Jr., and Harris, E.E., 1969, Water resources and development in 

Mason Valley, Lyon and Mineral Counties, Nevada, 1948-65: Nevada Division of Water Resources Bulletin 38, 77 p.

Huxel, C.J., Jr., Parkes, J.E., and Everett, D.E., 1966, Effects of irrigation development on the water supply of Quinn River Valley area, Nevada and Oregon, 1950-64: Nevada Department of Conservation and Natural Resources 

Water Resources Bulletin 34, 80 p.

Jennings, C.W., comp., 1977, Geologic map of California: California Division 

of Mines and Geology Geologic Data Map 2, scale 1:750,000.

Kohler, M.A., Nordenson, T.J., and Baker, D.R., 1959, Evaporation maps for 

the United States: U.S. Department of Commerce Weather Bureau Technical Paper 37, 13 p.

Langenheim, R.L., Jr., and Larson, E.R., 1973, Correlation of Great Basin stratigraphic units: Nevada Bureau of Mines and Geology Bulletin 72, 19 p.

Malmberg, G.T., and Eakin, T.E., 1962, Ground-water appraisal of Sarcobatus 

Flat and Oasis Valley, Nye and Esmeralda Counties, Nevada: Nevada 

Department of Conservation and Natural Resources Ground-Water 

Resources Reconnaissance Report 10, 39 p.

Malmberg, G.T., and Worts, G.F., 1966, The effects of pumping on the hydrology of Kings River Valley, Humboldt County, Nevada, 1957-64: Nevada 

Department of Conservation and Natural Resources Water Resources Bulletin 31,57 p.

Mason, J.L., 1998, Ground-water hydrology and simulated effects of development in the Milford area, an arid basin in southwestern Utah: U.S. 

Geological Survey Professional Paper 1409-G, 78 p., 2 pis.

Mason, J.L., Atwood, John, and Buettner, Priscilla, 1985, Selected test well 

data from the MX missile system study, Tooele, Millard, Beaver, and 

Iron Counties, Utah: U.S. Geological Survey Open-File Report 85-347, 

13 p., 1 pi.

Maxey, G.B., and Eakin, T.E., 1949, Ground water in White River Valley, White 

Pine, Nye, and Lincoln Counties, Nevada: Nevada State Engineer, Water 

Resources Bulletin 8, 59 p.

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional 

finite-difference ground-water flow model: U.S. Geological Survey Techniques of Water-Resources Investigations, book 6, chap. Al, 586 p.

Meinzer, O.E., 1917, Geology and water resources of Big Smoky, Clayton, and 

Alkali Spring Valleys, Nevada: U.S. Geological Survey Water-Supply Paper 

423, 167 p.

Mendenhall, W.C., 1909, Some desert watering places in southeastern California and southwestern Nevada: U.S. Geological Survey Water-Supply Paper 

224, 98 p.

Mifflin, M.D., 1968, Delineation of ground-water flow systems in Nevada: University of Nevada Desert Research Institute Technical Report H-W no. 4, 

112 p.

 1988, Region 5, Great Basin, in Back, William, Rosenshein, J.S., and 

Seaber, PR., eds., Hydrogeology: Boulder, Colo., Geological Society of 

America, The geology of North America, v. O-2, p. 69-78.

Mifflin, M.D., and Harrill, J.R., 1981, Hydrogeologic characteristics of the 

Great Basin [abs.]: Geological Society of America Abstracts with Programs, v. 13, no. 7, p. 510.

Miller, G.A., 1977, Appraisal of the water resources of Death Valley, California-Nevada: U.S. Geological Survey Open-File Report 77-728, 68 p.

Mower, R.W, 1965, Ground-water resources of Pavant Valley, Utah: U.S. Geological Survey Water-Supply Paper 1974, 78 p.

Nolan, T.B., 1943, The Basin and Range Province in Utah, Nevada, and California, chap. D of Shorter contributions to general geology, 1941^2: U.S. 

Geological Survey Professional Paper 197-D, p. 141-196.

Peterson, D.L., 1974, Bouguer gravity map of parts of the northern Lake Bonneville Basin, Utah and Idaho: U.S. Geological Survey Miscellaneous Field 

Studies Map MF-627, scale 1:250,000.

Plume, R.W., 1984, Use of aeromagnetic data to define some properties of 

a carbonate-rock aquifer in eastern Nevada [abs.]: Geological Society 

of America, Abstracts with Programs, v. 16, no. 6., p. 624.

 1985, Geologic features that control regional ground-water movement 

in the eastern Great Basin, Nevada and Utah [abs.]: Geological Society 

of America Abstracts with Programs, v. 17, p. 691.

 1988a, Geologic features that affect the movement of recharge to 

ground-water basins adjacent to the central Egan Range, White Pine 

County, Nevada [abs.]: Geological Society of America Abstracts with 

Programs, v. 20, no. 3, p. 221.

 1988b, Use of aeromagnetic data to define boundaries of a carbonaterock aquifer in east-central Nevada, in Subitzky, Seymour, ed., Selected 

papers in the hydrological sciences: U.S. Geological Survey Water-Supply Paper 2330, p. 1-10.

 1996, Hydrogeologic framework of aquifer systems in the Great Basin 

region of Nevada, Utah, and adjacent States: U.S. Geological Professional Paper 1409-B, 64 p.

Plume, R.W., and Carlton, S.M., 1988, Hydrogeology of the Great Basin 

region of Nevada, Utah, and adjacent States: U.S. Geological Survey 

Hydrologic Investigations Atlas HA-694-A, scale 1:1,000,000.
AQUIFER SYSTEMS IN THE GREAT BASIN OF NEVADA, UTAH, AND ADJACENT STATES SUMMARY REPORT A65

Price, Don, and Bolke, E.L., 1976, Hydrologic reconnaissance of the Sink Valley area, Tooele and Box Elder Counties, Utah: Utah Department of Natural 

Resources Technical Publication 26, 34 p.

Prudic, D.E., Harrill, J.R., and Burbey, T.J., 1995, Conceptual evaluation 

of regional ground-water flow in the carbonate-rock province of the 

Great Basin, Nevada, Utah, and adjacent States: U.S. Geological Survey Professional Paper 1409-D, 102 p.

Prudic, D.E., and Herman, M.E., 1996, Ground-water flow and simulated 

effects of development in Paradise Valley, a basin tributary to the Humboldt River in Humboldt County, Nevada: U.S. Geological Survey Professional Paper1409-F, 92 p.

Prudic, D.E., and Wood, J.L., 1995, Results of hypothetical ground-water 

pumping in Carson Valley, a river-dominated basin in Douglas County, 

Nevada, and Alpine County, California: U.S. Geological Survey WaterResources Investigations Report 95-4174, 29 p.

Robbins, S.L., Prudic, D.E., Schaefer, D.H., and Clutsom, F.G., 1985, Principal facts and density estimates for borehole gravity stations in three 

water wells located in Dixie and Paradise Valleys, Nevada: U.S. Geological Survey Open-File Report 85-426, 20 p.

Robinson, T.W., 1970, Evapotranspiration by woody phreatophytes in the Humboldt River valley near Winnemucca, Nevada, with a section on Soil-moisture determinations, by A.O. Waananen: U.S. Geological Survey 

Professional Paper 491-D, 41 p.

Rush, F.E., 1964, Ground-water appraisal of the Meadow Valley area, Lincoln 

and Clark Counties, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 27, 43 p.

 1967, Water-resources appraisal of Washoe Valley, Nevada: Nevada 

Department of Conservation and Natural Resources Water Resources 

Reconnaissance Report 41, 39 p.

 1968a, Index of hydrographic areas in Nevada: Nevada Division of Water 

Resources Information Report 6, 38 p.

 1968b, Water-resources appraisal of Clayton Valley-Stonewall Flat area, 

Nevada and California: Nevada Department of Conservation and Natural 

Resources Water Resources Reconnaissance Report 45, 54 p.

 1968c, Water-resources appraisal of the Lower Moapa-Lake Mead area, 

Clark County, Nevada: Nevada Division of Water Resources Reconnaissance Report 50, 66 p.

 1968d, Water-resources appraisal of Thousand Springs Valley, Elko 

County, Nevada: Nevada Division of Water Resources Reconnaissance 

Report 47, 61 p.

 1971, Regional ground-water systems in the Nevada Test Site area, Nye, 

Lincoln, and Clark Counties, Nevada: Nevada Division of Water Resources 

Reconnaissance Report 54, 25 p.

Rush, F.E., and Eakin, T.E., 1963, Ground-water appraisal of Lake Valley in 

Lincoln and White Pine Counties, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance 

Report 24, 29 p.

Rush, F.E., and Everett, D.E., 1966, Water-resources appraisal of Little Fish 

Lake, Hot Creek, and Little Smoky Valleys, Nevada: Nevada Department of 

Conservation and Natural Resources Reconnaissance Report 38, 39 p.

Rush, F.E., and Glancy, P.A., 1967, Water-resources appraisal of the Warm 

Springs-Lemmon Valley area, Washoe County, Nevada: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 43, 70 p.

Rush, F.E., and Huxel, C.J., 1966, Ground-water appraisal of the EldoradoPiute Valley area, Nevada and California: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 36, 30 

PRush, F.E., and Katzer, T.L., 1973, Water-resources appraisal of Fish Lake Valley, Nevada and California: Nevada Division of Water Resources Reconnaissance Report 58, 70 p.

Rush, F.E., and Kazmi, S.A.T., 1965, Water-resources appraisal of Spring Valley, White Pine and Lincoln Counties, Nevada: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 

33, 39 p.

Rush, F.E., and Schroer, C.V, 1971, Water resources of Big Smoky Valley, 

Lander, Nye, and Esmeralda Counties, Nevada: Nevada Division of Water 

Resources Bulletin 41, 84 p.

 1976, Geohydrology of Smith Valley, Nevada, with special reference to the 

water-use period 1953-72: Nevada Division of Water Resources Bulletin 

43, 95 p.

Schaefer, D.H., 1988, Bouguer gravity anomaly maps of Paradise, Stagecoach, Dixie, Fairview, and Stingaree Valleys, northwestern Nevada: 

U.S. Geological Survey Geophysical Investigations Map GP-985.

Schaefer, D.H., 1993, Documentation of model input and output values for 

simulation of regional ground-water flow, carbonate-rock province, 

Nevada, Utah, and adjacent States: U.S. Geological Survey Open-File 

Report 93^120 (revision of Open-File Report 91^179), 4 p., 1 diskette.

Schaefer, D.H., Duffrin, B.C., and Plume, R.W., 1986, Principal facts for 

gravity stations in Paradise and Stagecoach Valleys, Humboldt and 

Lyon Counties, Nevada: U.S. Geological Survey Open-File Report 85- 

694,15 p.

Schaefer, D.H., Thomas, J.M., and Duffrin, B.C., 1984, Principal facts for 

gravity stations in Dixie, Fairview, and Stingaree Valleys, Churchill 

and Pershing Counties, Nevada: U.S. Geological Survey Open-File 

Report 84-586,15 p.

Schulke, D.F., ed., 1987, Great Basin recharge studies: University of 

Nevada Desert Research Institute Water-Resources Center Publication 

41104,127 p.

Scott, B.R., Smales, T.J., Rush, F.E., and Van Denburgh, A.S., 1971, Nevada's 

water resources: Nevada Division of Water Resources Water for Nevada 

Report 3, 87 p.

Sinclair, W.C., 1962a, Ground-water resources of Desert Valley, Humboldt and 

Pershing Counties, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 7, 23 p.

 1962b, Ground-water resources of Pine Forest Valley, Humboldt County, 

Nevada: Nevada Department of Conservation and Natural Resources 

Ground-Water Resources Reconnaissance Report 4, 22 p.

 1963a, Ground-water appraisal of the Black Rock Desert area, northwestern Nevada: Nevada Department of Conservation and Natural Resources 

Ground-Water Resources Reconnaissance Report 20, 33 p.

 1963b, Ground-water appraisal of Duck Lake Valley, Washoe County, 

Nevada: Nevada Department of Conservation and Natural Resources 

Ground-Water Resources Reconnaissance Report 17, 19 p.

 1963c, Ground-water appraisal of the Long Valley-Massacre Lake region, 

Washoe County, Nevada: Nevada Department of Conservation and Natural 

Resources Ground-Water Resources Reconnaissance Report 15, 19 p.

 1963d, Ground-water appraisal of Pueblo Valley-Continental Lake region, 

Humboldt County, Nevada: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 22, 25 p.

Stephens, J.C., 1974a, Hydrologic reconnaissance of the northern Great Salt 

Lake Desert and summary hydrologic reconnaissance of northwestern Utah: 

Utah Department of Natural Resources Technical Publication 42, 55 p.

 1974b, Hydrologic reconnaissance of the Wah Wah Valley drainage basin, 

Millard and Beaver Counties, Utah: Utah Department of Natural Resources 

Technical Publication 47, 53 p.

 1976, Hydrologic reconnaissance of the Pine Valley drainage basin, Millard, Beaver, and Iron Counties, Utah: Utah Department of Natural 

Resources Technical Publication 51, 38 p.

 1977, Hydrologic reconnaissance of the Tule Valley drainage basin, Juab 

and Millard Counties, Utah: Utah Department of Natural Resources Technical Publication 56, 37 p.

Stephens, J.C., and Hood, J.W, 1973, Hydrologic reconnaissance of Pilot Valley, Utah and Nevada: Utah Department of Natural Resources Technical 

Publication 41,38 p.
A66 REGIONAL AQUIFER-SYSTEM ANALYSIS GREAT BASIN, NEVADA-UTAH

Stephens, J.C., and Sumsion, C.T., 1978, Hydrologic reconnaissance of the 

Dugway Valley-Government Creek area, west-central Utah: Utah Department of Natural Resources Technical Publication 59, 42 p.

Stewart, J.H., 1980, Geology of Nevada A discussion to accompany the geologic map of Nevada: Nevada Bureau of Mines and Geology Special Publication 4, 136 p.

 1988, Tectonics of the Walker Lane Belt, western Great Basin Mesozoic 

and Cenozoic deformation in a zone of shear, in Ernst, W.G., ed., Metamorphism and crustal evolution of the Western United States (Rubey Volume 

VII): Englewood Cliffs, N.J., Prentice-Hall, p. 683-713.

Stewart, J.H., and Carlson, J.E., 1978, Geologic map of Nevada: U.S. Geological Survey, scale 1:500,000.

Stokes, Lee, 1963, Geologic map of northwest Utah: Salt Lake City, University 

of Utah College of Mines and Mineral Industries, scale 1:250,000.

Sumsion, C.T., and others, 1976, Ground-water conditions in Utah, spring of 

1976: Utah Division of Water Resources Cooperative Investigations Report 

15, 69 p.

Thomas, J.M., Carlton, S.M., and Hines, L.B., 1989, Ground-water flow 

and simulated response to selected developmental alternatives in Smith 

Creek Valley, a hydrologically closed basin in Lander County, Nevada: 

U.S. Geological Survey Professional Paper 1409-E, 57 p.

Thomas, J.M., Mason, J.L., and Crabtree, J.D., 1986, Ground-water levels 

in the Great Basin region of Nevada, Utah, and adjacent States: U.S. 

Geological Survey Hydrologic Investigations Atlas HA-694-B, 2 sheets.

Thomas, J.M., Welch, A.H., and Dettinger, M.D., 1996, 1996, Aqueous 

geochemistry of aquifer systems in the Great Basin region of Nevada, 

Utah, and adjacent States: U.S. Geological Survey Professional Paper 

1409-C, 100 p.

Thomas, J.M., Welch, A.H., and Preissler, A.M., 1985, Geochemical evolution of ground water in a hydrologically closed basin, northern Basin 

and Range Province, Nevada [abs.], in Conference on Practical Applications of Ground-Water Geochemistry, Banff, Alberta, Canada, June 

1984, Proceedings: Alberta Research Council and National Water Well 

Association, p. 189.

 1989, Geochemical evolution of ground water in Smith Creek Valley, a 

hydrologically closed basin in central Nevada, U.S.A.: Applied 

Geochemistry, v. 4, p. 493-510.

Toth, J., 1962, A theory of groundwater motion in small drainage basins in central Alberta, Canada: Journal of Geophysical Research, v. 67, no. 11, p. 

4375^387.

 1963, A theoretical analysis of ground-water flow in small drainage basins: 

Journal of Geophysical Research, v. 68, no. 16, p. 4795^812.

Van Denburgh, A.S., and Glancy, PA., 1970, Water-resources appraisal of the 

Columbus Salt Marsh-Soda Spring Valley area, Mineral and Esmeralda 

Counties, Nevada: Nevada Division of Water Resources Reconnaissance 

Report 52, 66 p.

Van Denburgh, A.S., Lamke, R.D., and Hughes, J.L., 1973, A brief waterresources appraisal of the Truckee River Basin, western Nevada: Nevada 

Division of Water Resources Reconnaissance Report 57, 122 p.

Van Denburgh, A.S., and Rush, F.E., 1974, Water-resources appraisal of Railroad and Penoyer Valleys, east-central Nevada: Nevada Division of Water 

Resources Reconnaissance Report 60, 61 p.

Walker, G.E., and Eakin, T.E., 1963, Geology and ground water of Amargosa 

Desert, Nevada-California: Nevada Department of Conservation and Natural Resources Ground-Water Resources Reconnaissance Report 14, 45 p.

Welch, A.H., and Thomas, J.M., 1984, Aqueous geochemistry and isotope 

hydrology of the White River system, eastern Nevada [abs.]: Geological 

Society of America, Abstracts with Programs, v. 16, no. 6, p. 689.

Welch, A.H., and Williams, R.P., 1986a, Data on ground-water quality for 

the Elko 1° X 2° quadrangle, eastern Nevada: U.S. Geological Survey 

Open-File Report 85-648-B, scale 1:250,000.

 1986b, Data on ground-water quality for the Ely 1° X 2° quadrangle, 

eastern Nevada: U.S. Geological Survey Open-File Report 85-648-C, 

scale 1:250,000.

 1986c, Data on ground-water quality for the Lund 1° X 2° quadrangle, 

eastern Nevada: U.S. Geological Survey Open-File Report 85-648-D, 

scale 1:250,000.

 1986d, Data on ground-water quality for the Millett 1° X 2° quadrangle, central Nevada: U.S. Geological Survey Open-File Report 85-648- 

A, scale 1:250,000.

 1987a, Data on ground-water quality for the Caliente 1° X 2° quadrangle, eastern Nevada: U.S. Geological Survey Open-File Report 85-648- 

L, scale 1:250,000.

.....1987b, Data on ground-water quality for the Death Valley 1° X 2° 

quadrangle, southern Nevada: U.S. Geological Survey Open-File 

Report 85-648-M, scale 1:250,000.

..... 1987c, Data on ground-water quality for the Goldfield 1° X 2° quadrangle, central Nevada: U.S. Geological Survey Open-File Report 85- 

648-K, scale 1:250,000.

 1987d, Data on ground-water quality for the Kingman 1° X 2° quadrangle, southern Nevada: U.S. Geological Survey Open-File Report 85- 

648-N, scale 1:250,000.

 1987e, Data on ground-water quality for the Lovelock 1° X 2° quadrangle, western Nevada: U.S. Geological Survey Open-File Report 85- 

648-F, scale 1:250,000.

 1987f, Data on ground-water quality for the McDermitt 1° X 2° quadrangle, northern Nevada: U.S. Geological Survey Open-File Report 85- 

648-E, scale 1:250,000.

 1987g, Data on ground-water quality for the Reno 1° X 2° quadrangle, 

western Nevada: U.S. Geological Survey Open-File Report 85-648-H, 

scale 1:250,000.

 1987h, Data on ground-water quality for the Tonopah 1° X 2° quadrangle, central Nevada: U.S. Geological Survey Open-File Report 85- 

648-J, scale 1:250,000.

...-1987i, Data on ground-water quality for the Walker Lake 1° X 2° 

quadrangle, western Nevada: U.S. Geological Survey Open-File Report 

85-648-1, scale 1:250,000.

 1987J, Data on ground-water quality for the Winnemucca 1° X 2° 

quadrangle, central Nevada: U.S. Geological Survey Open-File Report 

85-648-G, scale 1:250,000.

Wernicke, Brian, 1985, Structural discordance between Neogene detachments 

and frontal Sevier thrusts, central Mormon Mountains, southern Nevada: 

Tectonics, v. 4, p. 213-246.

Winograd, I.J., 1962, Interbasin movement of ground water at the Nevada Test 

Site, Nevada, art. 104 in Short papers in geology and hydrology: U.S. Geological Survey Professional Paper 450-C, p. 108-111.

Winograd, I.J., and Eakin, T.E., 1965, Interbasin movement of ground water in 

south-central Nevada The evidence [abs.], in Abstracts for 1964: Geological Society of America Special Paper 82, p. 227.

Winograd, I.J., and Friedman, Irving, 1972, Deuterium as a tracer of regional 

ground-water flow, southern Great Basin, Nevada and California: Geological Society of America Bulletin, v. 83, no. 12, p. 3691-3708.

Winograd, I.J., and Thordarson, William, 1975, Hydrogeologic and hydrogeochemical framework, south-central Great Basin, Nevada-California, 

with special reference to the Nevada Test Site: U.S. Geological Survey Professional Paper 712-C, 126 p., 3 pis.

Worts, G.F., Jr., and Malmberg, G.T., 1966, Hydrologic appraisal of Eagle Valley, Ormsby County, Nevada: Nevada Department of Conservation and Natural Resources Water Resources Reconnaissance Report 39, 55 p.
Selected Series of U.S. Geological Survey Publications

Books and Other Publications

Professional Papers report scientific data and interpretations 

of lasting scientific interest that cover all facets of USGS investigations and research.

Bulletins contain significant data and interpretations that are of 

lasting scientific interest but are generally more limited in 

scope or geographic coverage than Professional Papers.

Water-Supply Papers are comprehensive reports that present 

significant interpretive results of hydrologic investigations of 

wide interest to professional geologists, hydrologists, and engineers. The series covers investigations in all phases of hydrology, including hydrogeology, availability of water, quality of 

water, and use of water.

Circulars are reports of programmatic or scientific information 

of an ephemeral nature; many present important scientific 

information of wide popular interest. Circulars are distributed 

at no cost to the public.

Fact Sheets communicate a wide variety of timely information 

on USGS programs, projects, and research. They commonly 

address issues of public interest. Fact Sheets generally are two 

or four pages long and are distributed at no cost to the public.

Reports in the Digital Data Series (DOS) distribute large 

amounts of data through digital media, including compact discread-only memory (CD-ROM). They are high-quality, interpretive publications designed as self-contained packages for viewing and interpreting data and typically contain data sets, 

software to view the data, and explanatory text.

Water-Resources Investigations Reports are papers of an 

interpretive nature made available to the public outside the formal USGS publications series. Copies are produced on request 

(unlike formal USGS publications) and are also available for 

public inspection at depositories indicated in USGS catalogs.

Open-File Reports can consist of basic data, preliminary 

reports, and a wide range of scientific documents on USGS 

investigations. Open-File Reports are designed for fast release 

and are available for public consultation at depositories.

Maps

Geologic Quadrangle Maps (GQ's) are multicolor geologic 

maps on topographic bases in 7.5- or 15-minute quadrangle 

formats (scales mainly 1:24,000 or 1:62,500) showing bedrock, 

surficial, or engineering geology. Maps generally include brief 

texts; some maps include structure and columnar sections only.

Geophysical Investigations Maps (GP's) are on topographic 

or planimetric bases at various scales. They show results of 

geophysical investigations using gravity, magnetic, seismic, or 

radioactivity surveys, which provide data on subsurface structures that are of economic or geologic significance.

Miscellaneous Investigations Series Maps or Geologic 

Investigations Series (I's) are on planimetric or topographic 

bases at various scales; they present a wide variety of format 

and subject matter. The series also incudes 7.5-minute quadrangle photogeologic maps on planimetric bases and planetary 

maps.

Information Periodicals

Metal Industry Indicators (Mil's) is a free monthly newsletter that analyzes and forecasts the economic health of five 

metal industries with composite leading and coincident 

indexes: primary metals, steel, copper, primary and secondary 

aluminum, and aluminum mill products.

Mineral Industry Surveys (MIS's) are free periodic statistical 

and economic reports designed to provide timely statistical data 

on production, distribution, stocks, and consumption of significant mineral commodities. The surveys are issued monthly, 

quarterly, annually, or at other regular intervals, depending on 

the need for current data. The MIS's are published by commodity as well as by State. A series of international MIS's is also 

available.

Published on an annual basis, Mineral Commodity Summaries is the earliest Government publication to furnish estimates 

covering nonfuel mineral industry data. Data sheets contain 

information on the domestic industry structure, Government 

programs, tariffs, and 5-year salient statistics for more than 90 

individual minerals and materials.

The Minerals Yearbook discusses the performance of the 

worldwide minerals and materials industry during a calendar 

year, and it provides background information to assist in interpreting that performance. The Minerals Yearbook consists of 

three volumes. Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Volume II, Area Reports: 

Domestic, contains a chapter on the minerals industry of each 

of the 50 States and Puerto Rico and the Administered Islands. 

Volume III, Area Reports: International, is published as four 

separate reports. These reports collectively contain the latest 

available mineral data on more than 190 foreign countries and 

discuss the importance of minerals to the economies of these 

nations and the United States.

Permanent Catalogs

"Publications of the U.S. Geological Survey, 1879-1961" 

and "Publications of the U.S. Geological Survey, 1962- 

1970" are available in paperback book form and as a set of 

microfiche.

"Publications of the U.S. Geological Survey, 1971-1981" is

available in paperback book form (two volumes, publications 

listing and index) and as a set of microfiche.

Annual supplements for 1982, 1983, 1984, 1985, 1986, and 

subsequent years are available in paperback book form.