U.S. Department of the Interior a U.S. Geological Survey

U.S. Geological Survey

Programs in Nevada

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1920 1930 1940 1950 1960 1970 1980 1990 2000

NEVADA POPULATION, IN MILLIONS

D. Railroad Valley

A. Pyramid Lake B. Fortitude Mine

C. Walker Lake, 1971

The U.S. Geological Survey (USGS) has 

been collecting and interpreting naturalresources data in Nevada for more than 100 

years. The long-term commitment enables 

planners to manage better the resources of a 

State noted for paradoxes. Although Nevada 

is one of the most sparsely populated States 

in the Nation, it has the fastest growing population (fig. 1). Although 90 percent of the 

land is rural, most of Nevada’s population is 

urban. Nevada is the most arid State and 

relies heavily on scarce water resources.

Historically, mining and agriculture have 

formed the basis of the economy. Now, 

urban development and tourism also have 

become important. Scenic lakes, valleys, 

and mountains are the principal natural 

tourist attractions (fig. 1).

Collection, analysis, and interpretation 

of earth science information by the USGS 

are indispensable to sound planning. The 

USGS works with more than 40 local, State, 

and Federal agencies and Indian Tribes in 

Nevada to provide natural-resources information for immediate and long-term decisions.

Mining and Water in the 

Humboldt River Basin

The advent of leaching processes that 

use cyanide (toxic in sufficient concentrations) for recovery of gold from low-grade 

ore has resulted in a mining boom, particularly in the Humboldt River Basin. Several 

large open-pit mines are currently being 

dewatered at rates as high as 70,000 gallons 

per minute. A small portion of this water is 

used for operations and processing. Most of 

it is redistributed by infiltration, reinjection, 

irrigation of agricultural lands, or surface 

discharge into the Humboldt River or its 

tributary channels. The localized and cumulative effects are not well understood, especially in combination with effects of longstanding irrigation practices and increasing 

municipal growth. 

In addition to potential hydraulic effects, 

changes in water quality, including 

increased stream temperatures and sediment transport might adversely affect 

endangered Lahontan cutthroat trout 

within the Basin. Finally, the quality of 

water in pit-water lakes is of long-term 

environmental concern because these water 

bodies lie along the Pacific Flyway used by 

migratory birds.

USGS scientists, in cooperation with the 

Nevada Department of Conservation and 

Natural Resources, the Nevada Bureau of 

Mines and Geology (NBMG), and the 

Bureau of Land Management (BLM), are 

studying geologic, geochemical, and hydrologic aspects of the Basin to increase understanding of the potential effect on 

resources. This information will be valuable to Federal and State agencies in making land- and resource-management 

decisions for northern Nevada.

Index of Subjects

Mining and Water in the Humboldt Basin

Minerals Assessment and Research

Water Budget and Salinity of Walker Lake

Decision Support System for the Truckee and 

the Carson River Basins

National Water-Quality Assessment Program 

Irrigation Drainage and Wildlife-Management 

Areas

Land Subsidence in Las Vegas Valley

Ground-Water Movement at the Nevada 

Test Site and Yucca Mountain

Topographic Mapping 

Digital Raster Graphics

Geologic Mapping

Geologic Data Base for the Great Basin

Resource Assessment and Land 

Management

Collection of Hydrologic Data

Cooperative Programs

Figure 1. Population growth in Nevada. A, Pyramid Lake is known for its recreation and 

distinctive rock formations (Photograph by Steve Berris); B, Fortitude Mine produced about 2 

million ounces of gold between 1984 and 1993 (Photograph by Alan Welch); C, In June 1971, 

the surface of Walker Lake was 30 feet above level of July 1994 (Photograph by Steve Van 

Denburgh); D, Crows Nest Spring in Railroad Valley with carbonate rocks of Grant Range in 

background (Photograph by Steve Van Denburgh).

Earth Science in the Public Service
39°

119°

40°

NEVADA

CALIFORNIA

Lahontan


Res.ervoir

Carson


Sink

Lake


Tahoe

Pyramid


Lake

0 20 MILES

0 20 KILOMETERS

CALIFORNIA

NEVADA

EXPLANATION

Fallon

Truckee


Canal

SIERRA

Reno


Sparks

Carson


City

NEVADA

120°

115°30'

36°

36°30'

Las
 Vegas

Henderson

Las


Vegas Wash

115°

Lake


Mead

Truckee River Truckee River

Carson River Carson River

Boundary of


drainage basin

Minerals Assessment and 

Research

Because Nevada is a major mineralsproducing State, mining is a significant 

industry. The future of mining and land use 

in Nevada depends on an improved understanding of the genesis of the known deposits and an assessment of the potential for 

occurrence of unknown deposits. USGS 

geologists, in cooperation with the Mackay 

School of Mines and private industry, are 

investigating the nature and origin of large, 

low-grade gold deposits like those found 

near Carlin. Research has led to new interpretations and models that can be applied in 

exploration and mineral-resource assessment. Related research into the age of these 

deposits suggests that they were formed 

about 30 million to 42 million years ago as 

a result of region-wide processes, including 

faulting, volcanic activity, intrusion of molten rock, and circulation of waters that carries a variety of metals.

USGS geologists are mapping geology 

in the Alligator Ridge mining district at the 

southern end of the Carlin Trend at 

1:24,000 scale. The purpose of the mapping 

is to delineate ore controls for sedimenthosted ore deposits.

USGS scientists have used new computer techniques to reexamine rock-sample 

geochemistry for the Copper Canyon area. 

This area, which includes the Fortitude 

Mine (fig. 1B), contains major gold deposits. The new analysis reveals previously 

unrecognized patterns of metals around 

known deposits, which should help with 

understanding and locating new deposits. 

USGS geophysicists have reexamined 

regional gravity data to focus on deeply 

buried rocks. Their research has found a 

persistent gradient in the gravity data that 

corresponds with the Battle Mountain–

Eureka mineral belt. These results provide 

direct evidence that mineral deposits are 

controlled by large regional scale crustal 

structures and provide enhanced understanding that aid in the exploration for new 

mineral deposits. 

Water Budget and Salinity of 

Walker Lake 

Walker Lake (fig. 1C), which is a desert 

lake near Hawthorne, has gone dry several 

times during the last 10,000 years in 

response to changes in climatic and hydrologic conditions. The lake-surface altitude 

has decreased by 135 feet since 1882 when 

agricultural irrigation began in the basin. 

During the same period, dissolved-solids 

concentrations increased from about 2,500 

to 13,300 milligrams per liter as of July 

1994, threatening the Walker Lake ecosystem and the fish that depend on this ecosystem. The loss of the lake’s trout fishery 

would affect the economy of the local communities. Upstream users who are economically dependent upon availability of waterrights appropriations also would be 

affected. 

USGS hydrologists, in cooperation with 

the Walker River Paiute Tribe, have estimated changes in the salinity of Walker 

Lake in response to lake-level changes and 

salt inputs. The water budget shows that 

about 33,000 acre-feet per year of water in 

excess of the long-term average is needed 

to maintain the 1994 lake-surface altitude, 

assuming that hydrologic conditions as 

from 1939 to 1993 remain the same. To 

reduce the 1994 dissolved-solids concentration to 10,000 milligram per liter and to 

maintain a viable fishery, the lake-surface 

altitude would need to be raised about 20 

feet, which is equivalent to about 700,000 

acre-feet of water. To maintain this higher 

lake level, an additional 47,000 acre-feet 

per year would be needed. In 1995, the 

water level of Walker Lake rose about 5 

feet in response to 200 percent of normal 

snowpack in the Sierra Nevada headwaters.

Decision Support System for 

the Truckee and the Carson 

River Basins

The Truckee-Carson-Pyramid Lake 

Water Rights Settlement Act (Title II of 

Public Law 101–618) contains many 

requirements for U.S. Department of the 

Interior (DOI) agencies. The USGS is providing detailed water-resources data and 

analyses for the Carson and the Truckee 

River Basins of California and Nevada 

(fig. 2). A Federal river-monitoring network 

was designed and implemented to provide 

consistent long-term data. River basin simulation models are being developed, tested, 

and applied. Modeling efforts include precipitation-runoff models for 34 subbasins, 

flow-routing models of the Truckee and the 

Carson Rivers, temperature and total-dissolved-solids models of the Truckee River, 

and a river-operations model of the Truckee 

River. These efforts provide a framework 

for water-resource managers to assess alternatives for reservoir operations and waterrights allocations.

The USGS occupies a unique niche 

among the Federal agencies involved in 

settlement of the long standing legal, operations, and ecological issues in the Basins. 

Because the USGS does not have specific 

resource-management or regulatory 

responsibilities, it is recognized by other 

Federal agencies as an objective source of 

information to be used in further negotiations and in carrying out provisions of the 

Act.

National Water-Quality 

Assessment Program

In response to the lack of long-term, 

consistent information on water quality, the 

USGS developed the National Water-Quality Assessment (NAWQA) Program. 

NAWQA Program goals are to describe the 

status and trends in the quality of the 

Nation’s water resources and to provide 

scientific understanding of the major factors that affect surface- and ground-water 

quality. The Nevada Basin and Range 

NAWQA Project, which includes the Las 

Vegas Valley area and the Carson and the 

Truckee River Basins (fig. 2), was initiated 

in 1991. Project scientists are using multiFigure 2. Urban and hydrological features 

in the Carson and the Truckee River Basins 

and Las Vegas Valley.
disciplinary approaches to compare and 

contrast the effects of urban and agricultural activities on water quality.

In 1995, project scientists participated 

with other DOI agencies [the National Park 

Service, the National Biological Service, 

the U.S. Fish and Wildlife Service 

(USFWS), and the Bureau of Reclamation 

(BOR)] to assess the occurrence of synthetic organic compounds and inorganic 

trace elements in Las Vegas Bay of Lake 

Mead and to evaluate their accumulation 

and harmful health effects in fish. The 

results of this assessment are being used to 

design a sampling strategy for delineating 

source areas of potentially harmful constituents.

Irrigation Drainage and 

Wildlife-Management Areas

Since 1986, scientists of the USGS, the 

USFWS, and the BOR have studied and 

monitored water and wildlife resources of 

the Stillwater National Wildlife Refuge and 

other nearby wetlands near Fallon. The 

results of the work to date indicate that 

aquatic biota are adversely affected by 

human-caused hydrologic changes in the 

natural geochemistry of the Newlands Irrigation Project area. 

In 1995, three synoptic studies were 

made just before and during the irrigation 

season. More than 200 measurements of 

drainflow and dissolved-solids concentration were taken, and about 80 water and 

sediment samples were collected for 

organic and inorganic chemical analysis 

and for toxicity tests. Preliminary results 

suggest that the greatest concentrations of 

potentially harmful constituents are from 

lands in the peripheral areas of the Newlands Project. Data and reports from the 

studies are used to determine potential ecological effects of water-management alternatives considered for implementation of 

Public Law 101–618 and for continued 

negotiations over water rights and environmental concerns in the Carson Desert and 

tributary basins. 

Land Subsidence in Las Vegas 

Valley

Land subsidence and earth fissures 

owing to ground-water withdrawal are 

ongoing problems in many parts of Las 

Vegas Valley. The USGS, in cooperation 

with the Nevada State Engineer, the Las 

Vegas Valley Water District, and the 

NBMG, is researching a three-dimensional 

model that was developed from recently 

established mathematical concepts. Land 

subsidence within the Las Vegas Valley has 

been well documented and partly controlled 

through the use of artificial recharge of 

water to the principal-aquifer system underlying the Valley.

Recent field data indicate that horizontal 

deformation owing to pumping is sufficient 

to cause fissures under certain geologic conditions. Simulation results indicate that fissures can form where differential 

subsidence is large or where sharp changes 

in aquifer thickness exist, such as over a

buried bedrock high. Aquifer stresses are 

maximized at the margins of these geologic 

features, and resultant fissures are likely to 

migrate upward through brittle caliche 

deposits in the unsaturated zone.

Ground-Water Movement at the 

Nevada Test Site and Yucca 

Mountain

At the request of the U.S. Department of 

Energy, the USGS is studying the hydrologic effects of activities at the Nevada Test 

Site (NTS). Nuclear weapons have been 

tested at this remote location north of Las 

Vegas since the early 1950’s. The USGS 

operates the ground-water-monitoring networks at the NTS and Yucca Mountain, 

which is a potential location for the 

Nation’s first high-level nuclear waste 

repository. Hydrologists and geologists are 

determining the regional and local subsurface controls on the rate and path of groundwater flow at the site. The results are crucial 

to understanding the potential for radionuclides and other contaminants to be transported within regional aquifers and to 

contaminate future public water supplies.

 The USGS also is studying the longterm frequency and magnitude of floods in 

the Yucca Mountain area. In 1995, the 

USGS completed geodetic leveling measurements at Yucca Mountain. These data 

were used to determine vertical displacement across faults during historical times 

and establish rates of uplift.

Topographic Mapping

Among the most popular and versatile 

products of the USGS are its topographic 

maps. These maps depict basic natural and 

cultural features of the landscape, including 

elevation contours, and have long been 

favorites with the general public for outdoor 

uses. Nevada is covered by 1,990 maps at 

1:24,000 scale (1 inch equals 2,000 feet). 

The USGS has recently revised 13 topographic maps for the Carson City and the 

Lake Tahoe areas. The USGS also provides 

digital cartographic data for ground-water 

and hazard studies, and land and resource 

management.

Digital Raster Graphics

The USGS, in cooperation with the 

NBMG, has prepared Digital Raster Graphics (DRG), or scanned topographic maps, of 

the entire State for the USGS 1:100,000-

scale map series. The NBMG has placed 

these DRG’s on its Internet site for the public to use, at: http://nbmg.unr.edu

DRG’s also are being produced at the 

1:24,000-scale for the Truckee Meadows 

Fire Protection District in Washoe County 

to aid in fighting wildfires. Rather than relying solely on paper maps, firefighters can 

display the DRG’s on a PC-notebook display in the field and print copies of the maps 

in the office as needed.

Geologic Mapping

The National Cooperative Geologic 

Mapping Program provides for publication 

of maps by geologists in industry and universities, as well as those in State and Federal agencies. Geologic mapping, in 

cooperation with the NBMG, is conducted 

through this Program. 

In Nevada, the STATEMAP component 

of the National Cooperative Geologic Mapping Program funds geologic mapping that 

is focused on mineral resources (gold, silver, lead, copper, tungsten) and on geologic 

hazards associated with faults in the western part of the State.

To provide important information about 

the geologic, geophysical, and hydrologic 

framework of Las Vegas and the surrounding area, a multicooperator project began in 

1995. Initial mapping products are generalpurpose, digital geologic maps at scales of 

1:100,000 and 1:24,000. This mapping 

includes a detailed stratigraphic study of the 

basin-fill deposits of the Las Vegas Valley. 

As part of this study, an aerial-photographic 

study of the Lake Mead National Recreation Area was completed in 1995.
Geologic Data Base for the 

Great Basin

On a regional scale, the USGS is compiling and using a large geographic data 

base for the Great Basin, which includes 

most of Nevada and parts of Utah, Idaho, 

Oregon, and California. A prototype display- and-analysis interface is being used 

by the USGS and the U.S. Forest Service. 

More than 60 digital data layers have been 

compiled; several have been published on 

CD–ROM. The data layers focus on geologic information that can be used for 

resource assessment and land management. 

These layers include surface geology and 

faults, analyses of rock samples and stream 

sediments, gravity anomalies, pluvial lakes, 

lithotectonic terranes, radiometric-age 

dates, active mines, mining permits, and 

standard map base layers.

Resource Assessment and 

Land Management

As public agencies move toward integrating the human, biological, and physical 

aspects of Nevada lands, USGS scientists 

are providing a variety of resource assessments. In addition to those assessments, the 

USGS is assessing the fuel and nonfuel 

resources of the BLM’s Winnemucca District and Surprise Resource Area in northwestern Nevada. Deposits of gold, silver, 

tungsten, oil, and gas, as well as geothermal energy, continue to be developed there. 

The BLM needs information to predict 

likely locations and effects of continued 

exploration and development. Land-management issues in the area include the presence of threatened and endangered species, 

withdrawal of public lands from minerals 

development (the proposed Black RockHigh Rock National Conservation Area), 

and the effects of mine dewatering on 

ground-water resources.

Collection of Hydrologic Data

The systematic collection of hydrologic 

data and statistics on water use in Nevada is 

critically needed for the understanding and 

management of this vital resource. The 

USGS is the Nation’s principal water-datacollection agency. USGS data are accessible to the public and provide a basic 

resource for engineers, universities, and 

public agencies.

Surface-water runoff is highly variable 

areally and seasonally throughout Nevada. 

In 1994, the USGS collected and published 

surface-water data from 187 gaging stations, 165 peak-flow stations, 66 springs, 

and 22 lakes and reservoirs. The long-term 

response of ground-water levels in Nevada 

to climatic variations and pumping is, for 

the most part, unknown. The proper planning and management of State water 

resources requires long-term information 

on ground-water levels and basin-wide 

estimates of recharge and discharge in the 

ground-water system. In 1994, the USGS 

collected and published water levels for 

142 primary and 616 secondary observation wells. In cooperation with the Nevada 

Division of Water Resources, a new digital 

data base for managing well-log and 

well-permit information was implemented 

in 1995.

The quality of water depends on many 

natural and human-induced factors and 

trends. Because USGS monitoring activities generally are focused on the ambient 

quality of rivers and aquifers rather than on 

permitted discharges, they provide an 

essential supplement to regulatory monitoring by other agencies. In 1994, the 

USGS collected and published water-quality data for 177 surface-water sites, 154 

wells, and 5 precipitation stations. 

Cooperative Programs 

The USGS cooperates with more than 

40 local, State, and Federal agencies and 

Indian Tribes in Nevada. Partnerships with 

local and State agencies typically are 

financed on a matching-funds basis. In 

addition to those agencies, the USGS 

cooperates with the city of Reno, Clark 

County, the Walker River Irrigation District, the Nevada Division of Environmental Protection, the Desert Research 

Institute, and the Federal Emergency Management Agency.

The USGS cooperates with the NBMG 

on many studies in the Great Basin. The 

NBMG is a research unit of the Mackay 

School of Mines at the University of 

Nevada, Reno, and is the State geological 

survey. Scientists at NBMG conduct 

research and publish reports on mineral 

resources and various aspects of general, 

environmental, and engineering geology.

USGS State representative

333 West Nye Lane, Room 203

Carson City, NV 89706

(702) 887-7600

Fax: (702) 887-7621

Email: dc_nv@usgs.gov

Additional earth science

information can be found by

accessing the USGS Home Page

on the World Wide Web at

http://www.usgs.gov/

For more information on

all USGS reports and products

(including maps, images,

and computerized data), call

1-800-USA-MAPS

The USGS provides maps,

reports, and information to help

others meet their needs to manage,

develop, and protect America’s water,

 energy, mineral, biological, and land

resources. We help find the natural

resources needed to build tomorrow

and supply the scientific understanding needed to help minimize or mitigate the effects of natural hazards

and environmental damage caused

by natural and human activities. The

results of our efforts touch the daily

 life of almost every American.

U.S. Geological Survey

Fact Sheet FS-028-96

For More

Information