Prepared in cooperation with Elko County, Nevada

Hydrogeologic Framework and Occurrence and Movement of 

Ground Water in the Upper Humboldt River Basin, 

Northeastern Nevada

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5014
Cover: Photograph of Right Fork Lamoille Canyon looking 

south. (Photograph taken by Russell Plume, U.S. Geological 

Survey, Carson City, Nevada, June 1981.)

Photograph of Marys River looking south at the East Humboldt Range. 

(Photograph taken by Russell Plume, U.S. Geological Survey, Carson City, Nevada, 

April 1994.)

Photograph of late Eocene basin-fill deposits exposed at a gravel pit along State 

Route 226 about 1.3 miles west of State Route 225 (Mountain City Highway). The 

sediments exposed here are fairly typical of Tertiary age sediments that underlie 

basins of the study area (Alan Wallace, U.S. Geological Survey, written and oral 

commun., 2008). (Photograph taken by Russell Plume, U.S. Geological Survey, 

Carson City, Nevada, June 2007.)

NEOARCHEAN MESOARCHEAN PALEOARCHEAN EOARCHEAN 

SIDERIAN 

501.0 

513.0 

SERIES/ 

 EPOCH 

EONOTHEM/  EON ERATHEM/  ERA 

SYSTEM, SUBSYSTEM/  PERIOD, SUBPERIOD 

Age estimates of boundaries in mega-annum (Ma) 

0.012 

306.5 

311.7 

326.4 

345.3 

EONOTHEM/  EON 

ERATHEM/  ERA 

SYSTEM/ 

 PERIOD 

Age estimates of boundaries in mega-annum (Ma) 

PROTEROZOIC ARCHEAN HADIAN 

NEOPROTEROZOIC MESOPROTEROZOIC PALEOPROTEROZOIC 

EDIACARAN 

CRYOGENIAN 

TONIAN 

STENIAN 

ECTASIAN 

CALYMMIAN 

STATHERIAN 

OROSIRIAN 

RHYACIAN 

630 

850 

1000 

1200 

1400 

1600 

1800 

2050 

2300 

2500 

2800 

3200 

3600 

~4000 

Divisions of geologic time - major chronostratigraphic and 

 geochronologic units (U.S. Geological Survey Geologic 

 Names Committee, 2007). Reflects accepted and ratified 

 unit names and age estimates from the International 

 Commission on Stratigraphy.

359.2

299.0

270.6

542.0

488.3

471.8

460.9

260.4

443.7

397.5

385.3

318.1

428.2

422.9

418.7

416.0

65.5

1.81

5.33

23.03

33.9

55.8

251.0

245.0

228.0

199.6

175.6

161.2

145.5

99.6

PALEOZOIC

LOWER / EARLY

MIDDLE

UPPER / LATE

PALEOCENE

EOCENE

QUATERNARY

CENOZOIC

NEOGENE PALEOGENE

OLIGOCENE

MIOCENE

PLIOCENE

PLEISTOCENE

HOLOCENE

LOWER / EARLY

MIDDLE

CRETACEOUS

MESOZOIC

JURASSIC TRIASSIC

UPPER / LATE

LOWER / EARLY

MIDDLE

UPPER / LATE

UPPER / LATE

LOWER / EARLY

MIDDLE

UPPER / LATE

PRIDOLI

LUDLOW

WENLOCK

LLANDOVERY

LOWER / EARLY

MIDDLE

PERMIAN TERTIARY CARBONIFEROUS CAMBRIAN ORDOVICIAN SILURIAN DEVONIAN

FURONGIAN

LOWER / EARLY

CISURALIAN

LOPINGIAN

GUADALUPIAN

PENNSYLVANIAN MISSISSIPPIAN

UPPER / LATE

LOWER / EARLY

MIDDLE

MIDDLE

UPPER / LATE

LOWER / EARLY

PHANEROZOIC
Hydrogeologic Framework and Occurrence and 

Movement of Ground Water in the 

Upper Humboldt River Basin, 

Northeastern Nevada

By Russell W. Plume

Prepared in cooperation with Elko County, Nevada

Scientific Investigations Report 2009–5014

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2009

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Plume, R.W., 2009, Hydrogeologic framework and occurrence and movement of ground water in the upper Humboldt 

River basin, northeastern Nevada: U.S. Geological Survey Scientific Investigations Report 2009–5014, 22 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Background............................................................................................................................................1

Purpose and Scope ..............................................................................................................................3

Description of Study Area ...................................................................................................................3

Geologic Setting.............................................................................................................................................5

Hydrogeologic Units.............................................................................................................................5

Carbonate and Clastic Sedimentary Rocks.............................................................................5

Clastic Sedimentary Rocks ........................................................................................................7

Crystalline Rocks..........................................................................................................................8

Volcanic Rocks and Sedimentary Basin-Fill Deposits...........................................................8

Structural Features.............................................................................................................................12

Ground Water in the Upper Humboldt River Basin ................................................................................12

Occurrence and Movement..............................................................................................................12

Water-Level Change...........................................................................................................................13

Summary........................................................................................................................................................19

Acknowledgments.......................................................................................................................................20

References Cited..........................................................................................................................................20

Figures

Figure 1. Map showing selected features of the upper Humboldt River basin and 

location of streamflow-gaging stations, northeastern Nevada ..................... 2

Figure 2. Graph showing flow-duration curves for water years 1992–2007 at the Humboldt 

River near Elko and Carlin, Marys River below Twin Buttes, Lamoille Creek near 

Lamoille, and South Fork Humboldt River above Tenmile Creek gaging stations, 

northeastern Nevada........................................................................ 4

Figure 3. Map showing combined thickness of younger and older basin-fill deposits and 

volcanic rocks, and location of oil exploration wells, upper Humboldt River basin, 

northeastern Nevada........................................................................ 11

Figure 4. Map showing selected wells where water levels have fluctuated, 

upper Humboldt River basin, northeastern Nevada .................................... 14

Figure 5. Graphs showing water-level fluctuations at wells near Deeth and Lamoille......... 16

Figure 6. Graphs showing water-level fluctuation at well 3, 1965–2005 and annual 

precipitation as percent departure from average at Elko, Nevada, 1965–2005 ...... 17

Figure 7. Graphs showing water-level fluctuations at wells 4, 5, and 6 near South Fork 

Reservoir, Elko, Nevada..................................................................... 17

Figure 8. Graphs showing water-level fluctuations at wells 7, 8, and 9 near Elko, Nevada ... 18

Plate

Plate 1. Map showing hydrogeologic framework and ground-water levels in basin-fill 

deposits of the Upper Humboldt River basin, northeastern Nevada.
iv

Tables

Table 1. Hydrographic areas of the upper Humboldt River basin, northeastern Nevada ... 3

Table 2. Streamflow-gaging stations in the upper Humboldt River basin, northeastern

Nevada ....................................................................................... 4

Table 3. Lithology, thickness, extent, and water-bearing characteristics of

hydrogeologic units in the upper Humboldt River basin, northeastern Nevada. ... 6

Table 4. Hydrogeologic units penetrated by oil exploration wells in the upper

Humboldt River basin, northeastern Nevada............................................. 9

Table 5. Lithologies penetrated by wells 1–9, upper Humboldt River basin,

northeastern Nevada........................................................................ 15

Conversion Factors and Datums

Conversion Factors

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

square foot per day (ft2

/d) 0.09290 square meter per day (m2/d)

square foot (ft2

) 0.09290 square meter (m2)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

acre-foot (acre-ft) 1,233 cubic meter (m3

)

Flow rate

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times 

foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot 

squared per day (ft2/d), is used for convenience.

Datums

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29).

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27). 

Altitude, as used in this report, refers to distance above the vertical datum.
Abstract

The upper Humboldt River basin encompasses 

4,364 square miles in northeastern Nevada, and it comprises 

the headwaters area of the Humboldt River. Nearly all flow 

of the river originates in this area. The upper Humboldt 

River basin consists of several structural basins, in places 

greater than 5,000 feet deep, in which basin-fill deposits of 

Tertiary and Quaternary age and volcanic rocks of Tertiary 

age have accumulated. The bedrock of each structural basin 

and adjacent mountains is composed of carbonate and clastic 

sedimentary rocks of Paleozoic age and crystalline rocks of 

Paleozoic, Mesozoic and Cenozoic age. The permeability 

of bedrock generally is very low except for carbonate rocks, 

which can be very permeable where circulating ground water 

has widened fractures through geologic time.

The principal aquifers in the upper Humboldt River basin 

occur within the water-bearing strata of the extensive older 

basin-fill deposits and the thinner, younger basin-fill deposits 

that underlie stream flood plains. Ground water in these 

aquifers moves from recharge areas along mountain fronts to 

discharge areas along stream flood plains, the largest of which 

is the Humboldt River flood plain. The river gains flow from 

ground-water seepage to its channel from a few miles west of 

Wells, Nevada, to the west boundary of the study area.

Water levels in the upper Humboldt River basin 

fluctuate annually in response to the spring snowmelt and 

to the distribution of streamflow diverted for irrigation of 

crops and meadows. Water levels also have responded to 

extended periods (several years) of above or below average 

precipitation. As a result of infiltration from the South Fork 

Reservoir during the past 20 years, ground-water levels in 

basin-fill deposits have risen over an area as much as one 

mile beyond the reservoir and possibly even farther away in 

Paleozoic bedrock.

Introduction

Background

The Humboldt River basin is the largest river basin 

that is entirely within the State of Nevada. Numerous 

diversions reduce flow in the river, and the diverted surface 

water is used almost exclusively for irrigation of crops and 

meadows, especially in the middle and lower reaches. Even 

though the upper Humboldt River basin encompasses only 

about 25 percent of the entire river basin (fig. 1), the upper 

Humboldt River basin is the source of almost all of the total 

flow of the river.

Elko County officials and citizens are concerned about 

growing demand for water within the county and increasing 

external demands that are occurring statewide. Because flow 

of the Humboldt River and its tributaries is fully appropriated, 

any additional water needed to support growth in the upper 

Humboldt River basin presumably would come from ground 

water. However, ground water and streamflow can be 

intimately connected in lowland areas where ground-water 

discharge to the stream channel sustains flow (baseflow) 

during low runoff periods. Decisions to further develop the 

ground-water resources of the upper Humboldt River basin 

will need to consider the potential effects of such development 

on streamflow. County and State water-resource managers 

need information that will enable them to make informed 

decisions regarding future use of the ground-water resources 

of the upper Humboldt River basin. To address these needs 

and concerns, the U.S. Geological Survey (USGS), in 

cooperation with Elko County, evaluated the water resources 

of the upper Humboldt River basin in northeastern Nevada 

during Federal fiscal years 2007–08 (fig. 1).

Hydrogeologic Framework and Occurrence and 

Movement of Ground Water in the Upper Humboldt 

River Basin, Northeastern Nevada

By Russell W. Plume
2 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

tac08-4146_Figure 1

Diamond Mountains

Pinon Range

Ruby Mountains

Snake Mountains

Independence Mountains

Elko Hills

Peko

Hills

East Humboldt Range

Jarbidge Mountains

Adobe Range

Tenmile Creek

Tabor Creek

Starr Creek

South Fork

 Humboldt 

 River 

Marys River

Creek

Lamoille

Huntington

Creek

Dixie

Creek

Bishop Creek

Secret

Creek

Humboldt River

North

Fork Humboldt

River

South Fork

Reservoir

Huntington

Valley

South

Fork

Area

Dixie CreekTenmile Creek Area

Elko Segment

Lamoille

Valley

Marys

River

Area

North Fork

Area

Starr

Valley

Area

3

7

5

6 2

2

4

1

Lamoille

Elko

Deeth

Carlin

Wells

116°30'W 116°W 115°30'W 115°W

41°30'N

41°N

40°30'N

40°N

EXPLANATION

Gaging station and No.

Upper Humbolt River basin 

Humbolt River basin 

Base from U.S. Geological Survey digital data, 

1:250,000-scale, 2000. Universal Transverse 

Mercator projection, Zone 11. North American 

Datum of 1983. Shaded-relief base from 10-

meter Digital Elevation Model; sun illumination 

from northwest 45 degrees above horizon.

0 5 10 15 Miles 20

0 5 10 15 Kilometers 20

Double

Mountain

Figure 1. Selected features of the upper Humboldt River basin and location of streamflow-gaging stations, northeastern 

Nevada.
Introduction 3

Purpose and Scope

This report presents the Upper Humboldt River basin 

phase one results. The objective of this report is to provide 

hydrologic information that improves the understanding 

of the water resources of the upper Humboldt River basin; 

specifically the delineation of the hydrogeologic framework 

and descriptions of the occurrence and movement of ground 

water in and between the eight hydrographic areas that make 

up the basin. The hydrogeologic framework of the study 

area comprises the extent, both areally and at depth, of rocks 

and deposits that store and transmit ground water (aquifers) 

and rocks and deposits that impede the movement of ground 

water (confining or semiconfining units). Delineation of the 

hydrogeologic framework of the upper Humboldt River basin 

is based on geologic and hydrogeologic studies completed 

during the past 60–70 years. The discussion of the occurrence 

and movement of ground water is based on water levels that 

were measured during the spring and summer of 2007 in about 

160 wells.

Description of Study Area

The upper Humboldt River basin covers an area of 

4,364 mi2 in northeastern Nevada, and consists of eight 

hydrographic areas—Marys River Area, Starr Valley 

Area, North Fork Area, Lamoille Valley, South Fork Area, 

Huntington Valley, Dixie Creek–Tenmile Creek Area, and 

Elko Segment (fig. 1, table 1). These eight areas encompass 

the headwaters of the Humboldt River, which is the source of 

nearly all of the total flow of the river in years of average flow. 

From west to east, gaged tributaries of the upper Humboldt 

River are South Fork Humboldt River, North Fork Humboldt 

River, Lamoille Creek, and Marys River. Other tributaries 

include Secret, Starr, Tabor, and Bishop Creeks. Altitudes of 

land surface in the study area range from 4,900 to 5,900 ft 

along the flood plain of the Humboldt River to greater than 

11,000 ft in the highest parts of the Ruby Mountains. Each of 

the hydrographic areas is described briefly below.

The Marys River Area covers 1,073 mi2

 and is drained 

by Marys River and its tributaries on the north and west and 

by Bishop and Tabor Creeks on the east (fig. 1). The area is 

bounded by the Snake Mountains to the east, the Jarbidge 

Mountains to the north, the Peko Hills to the west, and by the 

Humboldt River to the south.

The Starr Valley Area covers 332 mi2 and is drained 

by Starr and Secret Creeks (fig. 1). The area consists of a 

northwest sloping pediment bounded by the East Humboldt 

Range to the east and the Humboldt River to the northwest.

The North Fork Area covers 1,110 mi2

 and consists of an 

upper and lower basin, both of which are drained by the North 

Fork Humboldt River and its numerous tributaries (fig. 1). 

The upper basin is bounded by the Independence Mountains 

to the west, the south end of the Jarbidge Mountains to 

the northeast, and the north end of the Adobe Range to the 

southeast. The lower basin is bounded by the Adobe Range 

and Peko Hills to the west and east, respectively, the south 

end of the Jarbidge Mountains to the north, and the Humboldt 

River to the south.

Lamoille Valley covers an area of 257 mi2 and is drained 

by Lamoille Creek and its tributaries (fig. 1). The area 

consists of Lamoille Canyon in the Ruby Mountains and a 

northwest sloping pediment bounded to the southeast by the 

mountains, to the northwest by the Humboldt River, and by 

low topographic divides between the Starr Valley Area to the 

east and the Dixie Creek–Tenmile Creek Area to the west.

The South Fork Area covers 99 mi2

 and is drained by 

the South Fork Humboldt River and its numerous tributaries 

(fig. 1). The area is bounded by topographic divides between 

the Dixie Creek–Tenmile Creek Area to the north and 

Huntington Valley to the south. The two divides converge to 

the northwest and join at the confluence of the South Fork 

Humboldt River and Huntington Creek. The Ruby Mountains 

form the high altitude uplands of the area.

Huntington Valley covers 787 mi2 and is drained by 

Huntington Creek and by several tributaries that originate in 

the northeast part of the area. The area is bounded by the Ruby 

Mountains to the east, by the Diamond Mountains and Pinon 

Range to the west, by low topographic divides to the south and 

north.

Table 1. Hydrographic areas of the upper Humboldt River basin, 

northeastern Nevada.

[See fig. 1 for locations of hydrographic areas. Hydrographic area: Formal 

hydrographic areas in Nevada were delineated systematically by the U.S. 

Geological Survey and Nevada Division of Water Resources in the late 1960s 

(Cardinalli and others, 1968; Rush, 1968). These areas have been the basic 

units for assembling hydrologic data and for regulating water use in the State 

since 1968. The official hydrographic area names, numbers, and geographic 

boundaries continue to be used in U.S. Geological Survey scientific reports 

and Nevada Division of Water Resources administrative activities. Area 

(square miles): From Rush (1968)]

Hydrographic area

Name Number Area 

(square miles)

Area 

(acres)

Marys River Area 42 1,073 686,720

Starr Valley Area 43 332 212,480

North Fork Area 44 1,110 710,400

Lamoille Valley 45 257 164,480

South Fork Area 46 99 63,360

Huntington Valley 47 787 503,680

Dixie Creek–Tenmile Creek Area 48 392 250,880

Elko Segment 49 314 200,960

Totals (rounded) 4,364 2,793,000
4 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

The Dixie Creek–Tenmile Creek Area covers 392 mi2 and 

is drained by the South Fork Humboldt River and its two main 

tributaries in the area—Dixie and Tenmile Creeks (fig. 1). 

Since December 1987, flow has been regulated by the South 

Fork Reservoir, which has a maximum altitude of 5,231.4 ft. 

The Dixie Creek–Tenmile Creek Area is bounded by the South 

Fork Area and Huntington Valley to the south, Lamoille Valley 

to the east, the Pinon Range to the west, and by a group of 

unnamed hills to the north that extend from the Elko Hills to 

the north end of the Pinon Range.

The Elko Segment covers 314 mi2 and consists of the 

Humboldt River flood plain and adjacent uplands (fig. 1). The 

area is bounded by the Adobe Range to the north and the Elko 

Hills and north end of the Pinon Range to the south.

Streamflow is an important component of the water 

resources of the upper Humboldt River basin. Although a 

detailed discussion of the streamflow characteristics of the 

study area is beyond the scope of this report, a short summary, 

with examples, will help to emphasize the importance of 

streamflow and its interactions with ground water. See Eakin 

and Lamke (1966) and Prudic and others (2006) for more 

details on streamflow characteristics of the Humboldt River.

The streamflow characteristics of the upper Humboldt 

River and its tributaries are summarized by the flow-duration 

curves in figure 2, which show the frequency, as percent of 

time, that a given stream discharge per square mile of drainage 

area was equaled or exceeded during the period of record 

for water years 1992–2007. The term “water year” means 

a 12-month period beginning on October 1 and ending the 

following September 30. The curves in figure 2 represent 

streamflow conditions of the Humboldt River at the Elko and 

Carlin gaging stations and at Marys River, Lamoille Creek, 

and South Fork Humboldt River above Tenmile Creek (see 

fig. 1 and table 2 for station locations and descriptions). All 

curves tend to flatten at their upper ends, indicating that high 

flows are dominated by snowmelt runoff (Searcy, 1959, p. 22). 

tac08-4146_Figure 02

0.0001

10

0.0002

0.0005

0.001

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

1

2

5

1 2 5 10 20 30 50 70 80 90 95 98 99

100

20

50

PERCENT OF TIME INDICATED DISCHARGE

WAS EQUALED OR EXCEEDED

DISCHARGE, IN CUBIC FEET PER SECOND PER SQUARE MILE

E lko (4)

C arlin (7)

M arys River (1)

South Fork (5)

Lamoille Creek (2)

Figure 2. Flow-duration curves for water years 1992–2007 at 

the Humboldt River near Elko and Carlin, Marys River below Twin 

Buttes, Lamoille Creek near Lamoille, and South Fork Humboldt 

River above Tenmile Creek gaging stations, northeastern Nevada. 

Numbers in parentheses refer to streamflow-gaging stations in 

figure 1 and table 2.

Table 2. Streamflow-gaging stations in the upper Humboldt River basin, northeastern Nevada.

[Streamflow-gaging station numbers are shown in figure 1. USGS site identification No.: This unique number can be used to access streamflow data for a 

streamflow-gaging station at http://waterdata.usgs.gov/nv/nwis/current/?type=flow]

Streamflow-gaging

station and No.

USGS site

identification No. Name

1 10315600 Marys River below Twin Buttes near Deeth

2 10316500 Lamoille Creek near Lamoille

3 10317500 North Fork Humboldt River at Devils Gate near Halleck

4 10318500 Humboldt River near Elko

5 10319900 South Fork Humboldt River above Tenmile Creek near Elko

6 10320000 South Fork Humboldt River above Dixie Creek near Elko

7 10321000 Humboldt River near Carlin 
Geologic Setting 5

At their lower ends, the curves for the Elko, Carlin, Lamoille 

Creek, and South Fork stations also flatten, which indicates 

that late summer and autumn baseflow of each stream is 

sustained by ground-water discharge to the stream channel 

(Searcy, 1959, p. 22). In contrast, the curve for the Marys 

River station steepens at its lower end indicating the stream 

at this site has no baseflow and goes dry every summer and 

autumn.

The curves also indicate that the runoff yield (discharge 

per square mile of drainage area) of Lamoille Creek is much 

greater than that of the other four stations. The reason for 

this is that the entire watershed above the Lamoille Creek 

station is at high altitude and is underlain by low permeability 

crystalline rocks. In contrast, the watersheds above the other 

four stations include large areas of low altitude and they are 

underlain by rocks of varying permeability.

Curves for the Elko and Carlin stations indicate similar 

flow characteristics at high to medium flows. At low flows, 

however, the curves diverge and flow at Carlin is an order of 

magnitude greater. Two reasons for this are that: (1) regulated 

flow of the South Fork Humboldt River provides a perennial 

source of discharge to the mainstem of the river between Elko 

and Carlin, and (2) flow in the Humboldt River increases 

downstream of the Elko gaging station due to ground-water 

discharge.

On October 19, 1992, after several years of below 

average precipitation, USGS measured the flow of the 

Humboldt River and its main tributaries and diversions at 

35 sites from the Elko to Imlay gaging stations (Emett and 

others, 1994, p. 475). Three sites were measured that day in 

the vicinity of Elko—Humboldt River near Elko, Humboldt 

River near Carlin (sites 4 and 7, fig. 1) and South Fork 

Humboldt River near Elko at its confluence with the mainstem 

Humboldt River. The timing of these measurements was such 

that daily minimum temperatures had been low enough to 

have minimized the effects of evapotranspiration, but not low 

enough to cause formation of ice and consequent reduction of 

streamflow. The three measurements together (Carlin station 

minus Elko station minus South Fork Station) indicate that the 

Elko to Carlin reach of the Humboldt River was gaining about 

9.1 ft3

/s or about 6,600 acre-ft/yr, as ground-water discharge to 

the river channel. This might be a minimum value of groundwater discharge to the river channel because several years of 

drought preceded the time of the measurements.

Geologic Setting

The upper Humboldt River basin consists of several 

deep structural basins in which basin-fill deposits of Tertiary 

and Quaternary1 age and volcanic rocks of Tertiary age 

1

 This term, and others such as Tertiary or Paleozoic, denotes ranges of 

geologic age. The geologic time scale on the inside front cover of this report 

gives ages in millions of years for these terms.

have accumulated. The bedrock of each basin and adjacent 

mountains are composed of carbonate and clastic sedimentary 

rocks of Paleozoic age, and crystalline rocks of Cambrian, 

Jurassic, and Tertiary age. Numerous geologic studies have 

been conducted in the area since about the 1930s in efforts to 

identify and characterize the different rocks and deposits that 

underlie the study area and to map their distribution.

Hydrogeologic Units

The numerous rock units and sedimentary deposits 

identified in previous studies were grouped into hydrogeologic 

units by Maurer and others (2004). These hydrogeologic units 

were regrouped into six hydrogeologic units in this report 

(pl. 1, table 3). The units, in order of decreasing age, are: 

(1) carbonate rocks and interbedded clastic sedimentary rocks 

of Cambrian to Permian age; (2) clastic sedimentary rocks of 

Ordovician to Devonian age; (3) crystalline rocks consisting 

of granitic intrusive and metamorphic rocks of Cambrian, 

Jurassic, and Tertiary age; (4) volcanic rocks of Tertiary age; 

(5) older basin-fill deposits of Tertiary age that comprise most 

of the alluvial fill in each basin; and (6) younger basin-fill 

deposits of Quaternary age that consist mostly of deposits 

along stream flood plains. Basin-fill deposits and carbonate 

rocks can have high permeability and transmit ground water, 

whereas, the other rocks generally have low permeability and 

impede the flow of ground water (Maurer and others, 2004). 

The lithology and water-bearing characteristics of each unit 

are discussed below and summarized in table 3.

Carbonate and Clastic Sedimentary Rocks

Carbonate and clastic sedimentary rocks consist 

of: (1) carbonate rocks (limestones and dolomites) with 

interbedded shales and sandstones of Cambrian through 

Devonian age, (2) mostly shales and sandstones of 

Mississippian and Pennsylvanian age, and (3) interbedded 

carbonate rocks, sandstones, and shales of Pennsylvanian and 

Permian age (pl. 1, table 3). The thickness of this sequence 

of rocks is at least 20,000 ft in the southern Ruby Mountains, 

10,000 ft in the Pinon Range and Snake Mountains, and 

4,000 ft in the Independence Mountains (Coats, 1987, 

p. 13–47). Parts of the unit that consist of carbonate rocks 

of Cambrian to Devonian age are exposed extensively in the 

southern Ruby Mountains, southern Pinon Range, and to a 

limited extent in western parts of the Snake Mountains and 

northeastern parts of the Independence Mountains (Coats, 

1987, pl. 1). Clastic sedimentary rocks, such as sandstone and 

shale of the Diamond Peak Formation and Chainman Shale, 

are exposed extensively in the Pinon Range, Adobe Range, 

and Peko Hills where they overlie the older carbonate rocks 

(Coats, 1987, pl. 1).
6 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

Table 3. Lithology, thickness, extent, and water-bearing characteristics of hydrogeologic units in the upper Humboldt River basin, 

northeastern Nevada.

[Abbreviations: ft, foot; Fm, formation]

Hydrogeologic 

unit

Geologic 

age

Rock or

stratigraphic unit Lithology Thickness and extent

Water-bearing 

characteristics

Younger basinfill depositsQuaternary Alluvium and glacial 

moraines

Sorted and interbedded 

clay, sand, and gravel 

along stream flood plains. 

Poorly sorted to unsorted 

clay, silt, sand, gravel, and 

boulders of alluvial fans 

and moraines.

Deposits of flood plains

probably do not exceed

a few tens of feet in

thickness. Moraines and

deposits of alluvial fans

probably range from

hundreds to more than

1,000 ft thick.

Together with 

older basin-fill 

deposits, comprise 

shallow water-table 

aquifers and deeper 

confined aquifers. 

Permeability highly 

variable depending 

on lithology.

Older basin-fill 

deposits

Quaternary and 

Tertiary

Older alluvium of stream 

terraces (Coats, 1987, 

p. 70), sedimentary 

deposits of the Miocene 

and Pliocene Elko Basin 

(Wallace and others, 

2008, p. 59–62), and 

limestone, conglomerate, 

sandstone, shale, and 

tuff of Oligocene to 

Paleocene age (Coats, 

1987, p. 51–62).

Poorly consolidated 

deposits of fluvial and 

lacustrine origin. Includes 

deposits of alluvial fans, 

stream flood plains, and 

shallow lakes. 

Deposits commonly 

are tuffaceous and are 

extensively interbedded 

with volcanic rocks.

Total thickness including 

interbedded volcanic rocks 

ranges from less than 500 ft 

mostly along basin margins 

to more than 5,000 ft in a 

deep and narrow structural 

basin that extends from 

southern Huntington Valley 

to northern Marys River 

Area (fig. 3).

Together with 

younger basin-fill 

deposits, comprise 

shallow water-table 

aquifers and deeper 

confined aquifers. 

Permeability highly 

variable depending 

on lithology.

Volcanic rocks Tertiary Volcanic rocks Ash-flow and air-fall 

tuffs, lava flows, and 

domes. Compositions 

include basalt, andesite, 

dacite, latite, and rhyolite 

(Coats, 1987, pl. 1 and p. 

51–67).

Extensively interbedded 

with older basin-fill 

deposits. See above for 

composite thickness.

Mostly impede 

ground-water flow 

because tuffs weather 

to clay and because 

of interbedded finegrained lake deposits. 

Presence of perennial 

streams in watersheds 

underlain by these 

rocks also indicates 

low permeability.

Crystalline 

rocks

Cambrian and 

Jurassic

Metamorphic rocks Metamorphic rocks 

include marble, schist, 

and gneiss. They are 

metamorphosed carbonate 

and clastic sedimentary 

rocks of Paleozoic age in 

the central and northern 

Ruby Mountains and Elko 

Hills.

Thickness of metamorphic 

rocks probably similar to 

nearby unmetamorphosed 

carbonate and clastic 

sedimentary rocks of 

Paleozoic age. Granitic 

rocks extend to great depths 

and can be much more 

extensive than indicated by 

outcrop area.

Impedes the 

movement of ground 

water.

Tertiary and 

Jurassic

Granitic intrusive rocks Granite and granodiorite 

in the central Ruby 

Mountains and alaskite in 

the southern Independence 

Mountains.

Clastic 

sedimentary 

rocks

Devonian to 

Ordovician

Woodruff Fm

Valmy Fm

Vinini Fm

Shale, siltstone, sandstone, 

quartzite, chert, and 

marine volcanic rocks. 

Structurally overlie along 

the Roberts Mountains 

thrust various units of 

carbonate rocks.

Thickness about 2,000 ft 

in the Snake Mountains, 

9,000 ft in northern 

Independence Mountains, 

4,700 ft in the Pinyon 

Range, and 4,000–10,000 ft 

in the Ruby Mountains 

(Coats, 1987, p. 10–13 and 

29–34).

Generally impedes 

movement of ground 

water. Presence of 

perennial streams in 

watersheds underlain 

by these rocks 

also indicates low 

permeability.
Geologic Setting 7

Hydrogeologic 

unit

Geologic 

age

Rock or

stratigraphic unit Lithology Thickness and extent

Water-bearing 

characteristics

Carbonate 

and clastic 

sedimentary 

rocks

Permian, 

Pennsylvanian 

and 

Mississippian

Edna Mountain Fm

Schoonover Fm

Diamond Peak Fm

Chainman Shale

Webb Fm

Shale, sandstone, sandy 

limestone, conglomerate, 

and chert. Depositionally 

overlie various units of 

carbonate rocks

Thickness at least 

20,000 ft in the Ruby 

Mountains, 10,000 ft in 

the Pinyon Range and 

Snake Mountains, and 

about 4,000 ft in the 

Independence Mountains. 

An oil well penetrated 

4,500 ft of carbonate 

rocks from the Devils 

Gate Limestone to the 

Hanson Creek Formation 

at the north end of the 

Pinon Range (Coats, 1987, 

p. 13–47). 

Comprise carbonaterock aquifers 

generally beneath 

basin-fill aquifers. 

High permeability 

due to solution 

widening of fracture 

zones. Absence of 

perennial streams 

in watersheds even 

partly underlain by 

these rocks indicates 

high permeability.

Permian to 

Cambrian

Phosphoria Fm

Strathearn Fm

Moleen Fm

Tomera Fm

Ely Limestone

Joana Limestone

Pilot Shale

Devils Gate Limestone

Nevada Formation

Lone Mountain Dolomite

Roberts Mountains Fm

Hanson Creek Fm

Eureka Quartzite

Pogonip Group

Windfall Fm

Dunderberg Shale

Hamburg Dolomite

Secret Canyon Shale

Geddes Limestone

Eldorado Dolomite

Pioche Shale

Prospect Mountain 

Quartzite

Intervals of limestone 

and dolomite interrupted 

by thinner intervals of 

shale, quartzite, and 

conglomerate. All units 

rarely present in a single 

mountain range. Underlie 

entire study area, but are 

concealed over large parts 

of mountain ranges by 

various units of clastic 

sedimentary rocks.

Table 3. Lithology, thickness, extent, and water-bearing characteristics of hydrogeologic units in the upper Humboldt River basin, 

northeastern Nevada.—Continued

[Abbreviations: ft, foot; Fm, formation]

The permeability of the combined unit of carbonate 

and clastic sedimentary rocks undoubtedly varies over a 

wide range because of the differing lithologies present. The 

permeability of clastic parts of the unit probably is relatively 

low. In contrast, carbonate rocks can be very permeable 

where circulating ground water has widened fractures through 

geologic time. Hydraulic conductivity ranges from 0.0005 to 

900 ft/d based on estimates from 23 carbonate rock aquifer 

tests conducted throughout the Great Basin (Plume, 1996, p. 

13). Additionally, the hydraulic conductivity of the carbonate 

rocks ranged from 0.1 to greater than 150 ft/d at two large gold 

mines (west of the study area) in the vicinity of Carlin (Maurer 

and others, 1996, p. 9–11). Lowest values reflect hydraulic 

properties of dense, unfractured rock and highest values reflect 

hydraulic properties of fracture zones that have been widened 

by dissolution. This range of values illustrates the importance 

of faulting and fracturing in the development of secondary 

porosity and permeability in carbonate rocks. A qualitative 

indication of the high permeability of carbonate rocks in the 

study area is the absence of perennial streams in watersheds 

of the southern Ruby Mountains (fig. 1), which are underlain 

almost entirely by carbonate rocks (pl. 1; Coats, 1987, pl. 1). 

In other parts of the study area, perennial mountain streams 

are common.

Clastic Sedimentary Rocks

Shale, siliceous shale, chert, quartzite, siltstone, and 

minor amounts of limestone and andesitic volcanic rocks of 

Ordovician through Devonian age were deposited in a deepwater marine environment adjacent to the continental shelf of 

Western North America, offshore from where carbonate rocks 

were being synchronously deposited. During Late Devonian 

to Early Mississippian time, the clastic sedimentary rocks 

were thrust eastward as much as 90 mi over the carbonate 

rocks along a low-angle fault named the Roberts Mountains 

thrust (Stewart, 1980, p. 36). This tectonic event is known as 

the Antler orogeny (Stewart, 1980, p. 36). Along the Roberts 

Mountains thrust in the study area, these clastic sedimentary 

rocks overlie carbonate and clastic rocks of equivalent age 

(Coats, 1987, p. 80–81). This hydrogeologic unit is exposed 

extensively in the Snake and Independence Mountains and to a 

lesser extent in the Adobe and Pinon Ranges and Diamond and 

Ruby Mountains (pl. 1).
8 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

The permeability of clastic sedimentary rocks of 

Ordovician to Devonian age varies widely depending on the 

degree to which the unit has been affected by faulting. At two 

large gold mines in the area of Carlin just west of the study 

area, the hydraulic conductivity of this unit was found to range 

from 0.001 to 0.5 ft/d in unfractured rock to as much as 100 

ft/d along faults (Maurer and others, 1996, p. 9–11).

Crystalline Rocks

Two types of crystalline rocks are found in the study 

area—metamorphic rocks and granitic rocks (pl. 1). 

Metamorphic rocks occur in the central and northern Ruby 

Mountains and East Humboldt Range. They formed as a 

result of the metamorphism (re-crystallization due to heat 

and pressure) of carbonate and clastic sedimentary rocks 

of Cambrian to Devonian age during part of the Paleozoic 

and again in the Mesozoic (Coats, 1987, p. 77–79). Textures 

and compositions include metaquartzite, calcite marble, 

gneiss, and schist. The thickness of metamorphic rocks 

may be as much as 20,000 ft, which is similar to that of 

unmetamorphosed carbonate rocks in southern parts of the 

Ruby Mountains.

Granitic rocks occur in the central Ruby Mountains, 

Elko Hills, southern Independence Mountains, and Pinon 

Range (pl. 1). Compositions include granite of Jurassic age 

and granodiorite of Tertiary age in the Ruby Mountains 

and alaskite of Tertiary age in the southern Independence 

Mountains and Pinon Range (Coats, 1987, pl. 1, p. 73–77). 

These rocks extend to great depth, and their distribution at 

depth can be much greater than that indicated by outcrop area.

The low permeability of crystalline rocks can be inferred 

from the presence of numerous perennial streams in the central 

and northern Ruby Mountains and East Humboldt Range. 

Every watershed in these parts of the mountain ranges has a 

stream that is perennial at least to the mountain front.

Volcanic Rocks and Sedimentary 

Basin-Fill Deposits

A thick sequence of alternating sedimentary deposits 

and volcanic rocks accumulated in structural basins of the 

study area from Eocene time to Holocene time (Coats, 1987, 

p. 50–71). The sequence consists of three hydrogeologic 

units listed in table 3 and shown on plate 1—volcanic rocks, 

older basin-fill deposits, and younger basin-fill deposits. 

Herein, the three units are discussed together because they 

are complexly interbedded. The composite thickness2 of the 

2

 Combined basin fill and volcanic rock thicknesses discussed above and 

shown in figure 3 are from a depth to pre-Tertiary basement grid developed 

for northern Nevada. The depths shown should be considered estimates 

that do not always agree with depths recorded for oil wells in table 4. (D.A. 

Ponce, U.S. Geological Survey, written and oral commun., 2007). The process 

of developing the grid and its uncertainties are described by Ponce (2004, 

p. 71–74 and figs. 6–3 and 6–9).

three units ranges from 1,000 ft to more than 5,000 ft in a deep 

narrow structural basin that extends from southern Huntington 

Valley to the southern Marys River Area paralleling the Ruby 

Mountains and East Humboldt Range (fig. 3). Thicknesses 

also range from 1,000 ft to more than 5,000 ft in northern 

parts of the Marys River and North Fork Areas and in part of 

the Elko Segment. Sixteen oil exploration wells drilled since 

1951 penetrated differing thicknesses of basin-fill deposits 

and volcanic rocks overlying older bedrock (fig. 3; table 4) as 

follows: 

•	 6,475 and 3,310 ft at wells 1 and 6 in the Marys River 

Area; 

•	 4,230 and 410 ft at wells 2 and 5 in the North Fork 

Area; 

•	 3,150 and 3,070 ft at wells 9 and 11 in Lamoille Valley; 

•	 1,900 and 5,490 ft at wells 8 and 10 in the Elko 

Segment; and 

•	 9,538, 8,170, and 3,700 ft at wells 14, 15, and 16 in 

Huntington Valley. 

Well 13 in Huntington Valley penetrated 11,926 ft of basin-fill 

deposits and never encountered pre-Tertiary bedrock. Logs for 

several of the wells also illustrate the complex interbedding 

of older and younger basin-fill deposits with volcanic rocks. 

Well 2 penetrated 1,690 ft of older basin fill, 1,110 ft of 

volcanic rocks, and another 1,430 ft of older basin fill. Well 10 

penetrated 3,420 ft of older basin fill, 900 ft of volcanic rocks, 

and another 1,170 ft of older basin fill. Well 11 penetrated 

909 ft of younger basin fill, 243 ft of older basin fill, 1,243 ft 

of volcanic rocks, and another 684 ft of older basin fill.

The oldest basin-fill deposits and volcanic rocks in the 

study area, consisting of basal conglomerate overlain by a 

sequence of welded tuffs, deposits of the Elko Formation 

(claystone, siltstone, shale, limestone, and tuff), and rhyolitic 

lava flows and domes, are of Eocene and earliest Oligicene 

age and are almost entirely north of the Humboldt River 

(Coats, 1987, p. 51–58). All of the basin-fill deposits are 

tuffaceous to differing extents. The total thickness exceeds 

3,000 ft; however, these rocks and deposits apparently do 

not constitute a continuous blanket over northern parts of 

the study area. According to Henry (2008), these deposits 

accumulated in and along at least three deep and wide 

eastward draining valleys during Eocene time. The valleys 

were separated by uplands from which any air-fall tuffs were 

eroded and re-deposited in the valleys.

From late Eocene to middle Miocene, the upper 

Humboldt River basin probably was an area undergoing 

erosion since deposits and volcanic rocks of this age span are 

absent. About 15–14 Ma (millions of years before present), 

during the middle Miocene, the Elko basin began to form as 

low-angle and high-angle faulting began along the west sides 

of the Ruby Mountains, East Humboldt Range, and Snake 

Mountains (Wallace and others, 2008, p. 58–61). 
Geologic Setting 9

Well No. Nevada 

permit No. API No.

Altitude of 

land surface 

(feet)

Total depth 

(feet)

Depth of 

unit top 

(feet)

Hydrogeologic units 

penetrated

Thickness 

(feet)

1 16 27-007-05010 5,973 6,612 0 Basin-fill deposits 1,600

1,600 Volcanic rocks 4,875

6,475 Carbonate rocks

2 178 27-007-05208 6,050 7,106 0 Older basin-fill deposits 1,690

1,690 Volcanic rocks 1,110

2,800 Older basin-fill deposits 1,430

4,230 Paleozoic rocks 

3 552 27-007-05245 6,619 8,843 0 Mississippian clastic rocks 3,600

3,600 Devonian carbonate rocks 

4 404 27-007-05233 6,076 10,000 0 Volcanic rocks 1,850

1,850 Older basin-fill deposits 200

2,050 Vinini Formation 4,400

6,450 Chainman Shale

5 377 27-007-05232 6,034 12,573 0 Younger basin-fill deposits 84

84 Volcanic rocks 88

172 Older basin-fill deposits 238

410 Mississippian clastic rocks 5,538

5,948 Carbonate rocks

6 12 27-007-05006 5,505 5,465 0 Younger basin-fill deposits 370

370 Older basin-fill deposits 2,940

3,310 Mississippian clastic rocks

7 729 27-007-05253 6,174 10,415 0 Volcanic rocks 1,230

1,230 Mississippian clastic rocks 7,579

8,809 Carbonate rocks

8 428 27-007-05234 5,910 8,865 0 Younger basin-fill deposits 115

115 Volcanic rocks 845

960 Older basin-fill deposits 940

1,900 Mississippian clastic rocks 4,040

5,940 Carbonate rocks

9 0 27-007-05004 5,250 4,125 0 Older basin-fill deposits 3,150

3,150 Carbonate rocks 500

3,650 Mississippian clastic rocks

10 182 27-007-05209 5,182 5,670 0 Older basin-fill deposits 3,420

3,420 Volcanic rocks 900

4,320 Older basin-fill deposits 1,170

5,490 Paleozoic rocks

11 24 27-007-05003 5,308 7,349 0 Younger basin-fill deposits 909

909 Older basin-fill deposits 243

1,152 Volcanic rocks 1,234

2,386 Older basin-fill deposits 684

3,070 Paleozoic rocks

Table 4. Hydrogeologic units penetrated by oil exploration wells in the upper Humboldt River basin, northeastern Nevada. 

[See pl. 1 and fig. 3 for well locations. Data obtained in 2007 from Nevada Bureau of Mines and Geology at http://www.nbmg.unr.edu/lists/oil/oil.htm. American 

Petroleum Institute (API) No.: Oil exploration wells are identified by their API number, which consists of three groups of digits separated by dashes. The API 

number for the first well in this table is 27-007-05010. The first two digits denote state (Nevada is 27). The second three digits denote county (Elko County is 

007). The last five digits are assigned sequentially to wells as they are permitted and drilled]
10 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

The Elko basin was large, extending from southern 

Huntington Valley to northern Marys River and from the 

structurally active Ruby Mountains–East Humboldt Range–

Snake Mountains on the east to the structurally inactive Adobe 

and Pinon Ranges on the west (Wallace and others, 2008, 

p. 58). Materials eroded from these mountain ranges spread 

across the basin accumulating as fine-grained lake deposits in 

lowlands and as alluvial fan and stream flood-plain deposits 

toward basin margins. This pattern of deposition continued 

into late Miocene (10–9 Ma) when the Elko basin began to 

drain externally resulting in non-deposition of sediments and 

erosion of existing ones (Wallace and others, 2008, p. 63). 

Non-deposition, erosion, and transport of sediments out of 

the basin continued through late Miocene and most of the 

Pliocene except for a brief period in middle Pliocene when 

ash-rich sediments similar to those of middle Miocene age 

accumulated (Wallace and others, 2008, p. 61).

Younger basin-fill deposits in the upper Humboldt River 

basin consist mostly of unconsolidated sand and gravel along 

active stream channels (pl. 1; Coats, 1987, p. 70–71). The 

deposits also form a thin cover overlying pediments of older 

basin-fill deposits in the northern Marys River and North Fork 

Areas (pl. 1 and A.R. Wallace, U.S. Geological Survey, oral 

and written commun., 2008). The younger basin-fill deposits 

in Huntington Valley, especially those on the east side, also 

could be a thin veneer of glacial outwash of Pleistocene 

age from the Ruby Mountains overlying older basin fill of 

middle Miocene age (A.R. Wallace, U.S. Geological Survey, 

oral commun., 2008). In Huntington Valley, thicknesses of 

younger basin-fill deposits penetrated by oil exploration wells 

range from 1,710 to 3,400 ft (wells 14, 15, and 16; table 4). 

However, distinguishing younger basin fill from older at 

such depths is problematic and could be open to different 

interpretations.

The hydraulic properties of basin-fill deposits and 

volcanic rocks have not been evaluated in the upper Humboldt 

River basin. Farther west, however, the hydraulic properties 

of basin-fill deposits have been evaluated at large gold mines 

along the Carlin Trend. The basin-fill deposits in this area are 

of Miocene age and accumulated under conditions similar to 

those of the middle Miocene Elko basin (Wallace and others, 

2008, p. 52–58). Near Carlin at the Gold Quarry mine, the 

transmissivity of older basin-fill deposits ranges from 780 to 

3,600 ft2

/d and hydraulic conductivity ranges from 2 to 7 ft/d 

(Plume, 1995, p. 17). Using well drillers’ logs to determine 

the ratio of coarse- to fine-grained sediments in the upper 

100 ft of flood-plain deposits along the Humboldt River (about 

60 mi west of the study area), Bredehoeft and Farvolden 

(1963, p. 201) estimated the sand-shale ratio to vary from 20 

to 70 percent. The hydraulic conductivity determined from 

specific capacity of selected wells varied from 25 to 40 ft/d 

(Bredehoeft and Farvolden, 1963, p. 201). These ratios and 

values of hydraulic conductivity also may apply to the upper 

Humboldt River basin, and a similar analysis of well logs 

would be very useful for making estimates of basin-fill aquifer 

properties in the study area.

Well No. Nevada 

permit No. API No.

Altitude of 

land surface 

(feet)

Total depth 

(feet)

Depth of 

unit top 

(feet)

Hydrogeologic units 

penetrated

Thickness 

(feet)

12 590 27-007-05248 6,376 9,050 0 Mississippian clastic rocks 4,498

4,498 Carbonate rocks

13 246 27-007-05214 5,443 11,926 0 Older basin-fill deposits 11,926

14 263 27-007-05217 5,557 10,950 0 Younger basin-fill deposits 2,102

2,102 Older basin-fill deposits 7,436

9,538 Paleozoic rocks

15 297 27-007-05223 5,535 10,320 0 Younger basin-fill deposits 3,400

3,400 Older basin-fill deposits 4,770

8,170 Paleozoic rocks

16 716 27-007-05252 5,955 4,157 0 Younger basin-fill deposits 1,710

1,710 Older basin-fill deposits 1,990

3,700 Carbonate rocks

Table 4. Hydrogeologic units penetrated by oil exploration wells in the upper Humboldt River basin, Nevada.—Continued

[See pl. 1 and fig. 3 for well locations. Data obtained in 2007 from Nevada Bureau of Mines and Geology at http://www.nbmg.unr.edu/lists/oil/oil.htm. American 

Petroleum Institute (API) No.: Oil exploration wells are identified by their API number, which consists of three groups of digits separated by dashes. The API 

number for the first well in this table is 27-007-05010. The first two digits denote state (Nevada is 27). The second three digits denote county (Elko County is 

007). The last five digits are assigned sequentially to wells as they are permitted and drilled]
Geologic Setting 11

tac08-4146_Figure 3

Diamond Mountains

Pinon Range

Ruby Mountains

Snake Mountains

Independence Mountains

Elko Hills

Peko

Hills

East Humboldt Range

Jarbidge Mountains

Adobe Range

Tenmile Creek

Tabor Creek

Starr Creek

South Fork

 Humboldt 

 River 

Marys River

Creek

Lamoille

Huntington

Creek

Dixie

Creek

Bishop Creek

Secret

Creek

Humboldt River

North

Fork Humboldt

River

Wells

Lamoille

Elko

Deeth

Carlin

7

12

16

16

3

8

4

5

15

14 13

10

2

1

6

11

9

South Fork

Reservoir

116°30'W 116°W 115°30'W 115°W

41°30'N

41°N

40°30'N

40°N

EXPLANATION

Depth to bedrock, in feet

0 to 1,000

>1,000 to 3,000

3,000 to >5,000

Oil exploration well and No. 

 listed in table 3

0 5 10 15 Miles 20

0 5 10 15 Kilometers 20

Base from U.S. Geological Survey digital data, 

1:250,000-scale, 2000. Thickness from depth 

to pre-Tertiary basement raster (D.A. Ponce, 

oral and written commun., 2007; Ponce, 

2004, p.71–74 and figures 6–3 and 6–9). 

Universal Transverse Mercator projection, 

Zone 11. North American Datum of 1983. 

Shaded-relief base from 10-meter Digital 

Elevation Model; sun illumination from 

northwest 45 degrees above horizon.

Upper Humbolt River basin 

Humbolt River basin 

Figure 3. Combined thickness of younger and older basin-fill deposits and volcanic rocks, and location of oil exploration 

wells, upper Humboldt River basin, northeastern Nevada.
12 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

Structural Features

Faults and related fractures can function as enhanced 

conduits for ground water flow, or impede flow where 

hydrogeologic units of differing permeability are juxtaposed 

or filled by fault gouge (pulverized rock along the fault zone 

produced by friction when a fault moves). Near large gold 

mines along the Carlin Trend, faults impede the movement of 

ground water where carbonate rocks are juxtaposed against 

volcanic and clastic sedimentary rocks (Plume, 2005, p. 6–7). 

The evidence that faults are barriers to flow in this area is 

the substantial water level difference, greater than 1,000 ft, 

across the faults after more than 15 years of pumping for mine 

dewatering (Plume, 2005, p. 6). In other cases, however, the 

effects of faults may not be known until large-scale pumping 

stresses are applied to an aquifer.

Ground Water in the Upper 

Humboldt River Basin

Occurrence and Movement

The occurrence and movement of ground water in the 

upper Humboldt River basin is interpreted using ground-water 

levels in 161 wells measured by personnel from the USGS, 

Nevada Division of Water Resources, and Newmont Mining 

Corporation during the spring and summer 2007. Water levels 

ranged from at or near land surface in younger basin-fill 

deposits along stream flood plains to 300–400 ft below land 

surface in older basin-fill deposits mostly along basin margins. 

Water-level contours in ft above sea level primarily reflect 

ground-water levels in older and younger basin-fill deposits, 

but also may reflect water levels in unconfined carbonate rock 

aquifers (pl. 1). 

Driven by hydraulic gradient, ground water moves 

through permeable zones from areas of recharge to areas of 

discharge. Recharge occurs mostly along mountain fronts, 

but also in mountainous areas underlain by carbonate rocks. 

Discharge occurs mostly on valley floors by evaporation from 

open water and moist soils and transpiration by plants called 

phreatophytes3, ground water seepage to stream channels, 

and pumpage. The main discharge area in the upper Humboldt 

River basin is the river flood plain, which can be as much as a 

mile wide. 

3

 Phreatophytes are plants that have their roots in ground water. They 

include greasewood, big sage, rabbit brush, various meadow grasses, 

willows, and cottonwoods. Evapotranspiration is the primary ground-water 

discharge process in the Humboldt River Basin and the term incorporates 

two processes—evaporation from open water and soils, and transpiration by 

phreatophytes.

In Huntington Valley and the South Fork Area, groundwater flow is from the western base of the Ruby Mountains 

toward Huntington Creek and its confluence with the 

South Fork Humboldt River. In Huntington Valley, groundwater flow also is from the eastern base of the Diamond 

Mountains and Pinon Range toward Huntington Creek. 

Water-level gradients range from 200 ft/mi adjacent to the 

Ruby Mountains to 10 ft/mi between the Pinon Range and 

Huntington Creek (pl. 1). This range of gradients either 

indicates that more recharge originates from the Ruby 

Mountains than from mountain ranges on the west side of 

the valley or that basin-fill deposits on the east side of the 

valley are less permeable than those on the west side. Rush 

and Everett (1966, p. 26–27) noted that basin-fill deposits on 

the east side of Huntington Valley are saturated to near land 

surface and that potential recharge is rejected and leaves the 

area as streamflow. The sharp, upstream inflections of waterlevel contours along the axis of Huntington Valley indicate 

that ground water discharges to the channel of Huntington 

Creek. However, ground water also flows northward along the 

axis of the valley along gradients of 5–10 ft/mi.

The high permeability of carbonate rocks likely result 

in recharge rather than runoff as indicated by the absence of 

perennial streams in the southern Ruby Mountains (fig. 1 and 

pl. 1). This, combined with the eastward dip of the rocks, 

probably results in ground-water flow from the west side of 

the southern Ruby Mountains to Ruby Valley east of the study 

area where numerous large springs emanate from the eastern 

base of the Ruby Mountains (Rush and Everett, 1966, p. 15; 

Dudley, 1967, p. 88–98). Dudley (1967, p. 97) also determined 

that the ground-water divide between Huntington and Ruby 

Valleys may be as much as 2 mi west of the topographic divide 

between the two valleys suggesting that most of the highaltitude precipitation in the southern Ruby Mountains does not 

recharge the upper Humboldt River basin. 

Ground-water flow from Huntington Valley and the 

South Fork Area continues northward into the Dixie Creek–

Tenmile Creek Area. In addition, ground water flows west and 

northwest from the recharge area along the mountain front of 

the Ruby Mountains and north and northeast from the Pinon 

Range. A low topographic divide separates the Dixie Creek–

Tenmile Creek Area from Lamoille Valley to the northeast. 

A group of unnamed hills separates the Dixie Creek–Tenmile 

Creek Area from the Humboldt River downstream from Elko. 

The water-level contours on plate 1 indicate that ground water 

flows northwest through these hills to the river flood plain.

In Lamoille Valley and Starr Valley Area ground-water 

flow is from a recharge area along the base of the Ruby 

Mountains, which are composed entirely of low permeability 

crystalline rocks. As a result, ground-water recharge is 

predominantly from infiltration of runoff from the mountains 

as it crosses the pediment between the mountains and 

Humboldt River flood plain. A portion of the water leaves 

the two basins as runoff because aquifers in both valleys 

are saturated to near land surface and have limited storage 

available for recharge (Eakin and Lamke, 1966. p. 31). 
Ground Water in the Upper Humboldt River Basin 13

Ground-water flow is to the northwest in Lamoille Valley and 

to the west in Starr Valley Area. Water-level gradients range 

from 50–100 ft/mi adjacent to the mountains to 10–30 ft/mi 

near the Humboldt River flood plain.

Ground-water flow in the Marys River Area generally 

is southward to the Humboldt River. The lower reaches of 

Marys River are ephemeral, and water-level contours have 

no upstream inflection unlike other streams in the study area. 

Near the Humboldt River flood plain, water-level gradients are 

about 20 ft/mi.

The North Fork Area consists of upper and lower 

topographic basins that are connected by streamflow through 

a canyon in the northern Adobe Range (fig. 1). The upper 

basin consists of an east sloping pediment of flat-lying to tilted 

older basin-fill deposits overlain by a thin cover of younger 

basin-fill deposits (A.R. Wallace, U.S. Geological Survey, 

oral commun., 2008), as much as 5 mi wide, between the 

Independence Mountains to the west and Double Mountain 

and the Adobe Range to the east. Sparse water-level data 

indicate that ground-water flow is eastward from a recharge 

area along the eastern base of the Independence Mountains. 

Water-level data are not sufficient to determine whether 

the direction of ground-water flow on the east side of the 

area turns northeastward parallel with the Adobe Range or 

continues eastward through the range. The first possibility 

would require a sharp change in the direction of flow from 

eastward to northeastward. The second does not seem 

likely because the principle rock types the Adobe Range are 

4,000–5,500 ft of poorly permeable shale and sandstone of the 

Diamond Peak Formation and Chainman Shale (oil wells 8 

and 5, pl. 1, table 4).

Ground-water flow in the lower part of the North Fork 

Area is southeastward from the Adobe Range, and as indicated 

by the 5,300- and 5,400-ft water-level contours southwestward 

from the Peko Hills toward the North Fork Humboldt River 

and then southward along the basin axis toward the Humboldt 

River (pl. 1). The Peko Hills are underlain by the Diamond 

Peak Formation, Chainman Shale, and by older and younger 

carbonate rocks.

Sharp upstream inflections of the water-level contours 

indicate that the Humboldt River gains flow from groundwater seepage from a few miles west of Wells to the west 

boundary of the study area. Water-level gradients along 

the flood plain range from about 7 to 30 ft/mi east of the 

Elko Hills. Ground-water flow in the Elko Segment (Elko 

Hills to the west boundary of the study area) is to the 

southeast from the Adobe Range and northwest from the 

Dixie Creek–Tenmile Creek Area through the unnamed hills 

between the Elko Hills and the South Fork Humboldt River. 

Streamflow gains of the river in the Elko Segment are about 

6,600 acre-ft/yr. This ground-water seepage to the river 

channel primarily moves through a 10-mi wide section of the 

unnamed hills (pl. 1) under a water-level gradient of 40 ft/mi 

(0.008 ft/ft). 

Transmissivity can be estimated using these values and a 

form of Darcy’s law:

 T = Q/(iw), (1)

where 

T is transmissivity, in feet squared per day; 

Q is flow through the section, in cubic feet per day;

i is the water table gradient, in feet per foot; and 

w is the width of the flow section, in feet.

The estimated transmissivity of the rocks and deposits 

in the flow section is about 2,000 ft2/d. However, this is a 

rough estimate because some subsurface flow resulting in the 

streamflow gains comes from the Adobe Range.

Water-Level Change

Water levels in the upper Humboldt River basin fluctuate: 

(1) annually in response to wetter (spring runoff) and drier 

(lack of summer rain) hydrologic conditions; and (2) to longer 

term (multiyear) variations in climate. Water-level data from 

nine wells were used to evaluate these fluctuations. The 

locations of these wells are shown in figure 4.

Wells 1 and 2 near Deeth and Lamoille, respectively, 

were measured monthly from 1949 to 1958 (fig. 4, fig. 5 A–B). 

Well 1 (fig. 5A) is in the flood plain near the confluence of 

Marys River and the Humboldt River, and water levels at this 

well probably respond rapidly to changes in stage of either 

stream. Water levels were about 10 ft below land surface in 

late winter to early spring, but rapidly rose to within 5 feet of 

land surface by early to late June. Although no drillers’ log 

is available for well 1, the log for a nearby well (Nevada log 

number 76997, table 5) penetrated interbedded sand, gravel, 

and clay from land surface to depths of 28 ft and blue clay to 

a depth of 112 ft. The sands and gravels above the blue clay 

function as a shallow water-table aquifer that is recharged 

mostly by the spring snowmelt runoff.

Monthly water-level fluctuations at well 2 were similar 

to those at well 1 (fig. 5B). Well 2 is located about one-half 

mile from Lamoille Creek in an area dissected by a network 

of ditches used to irrigate meadows and fields. Depth to water 

at this well was more than 10 ft in early to late winter, but 

typically rose abruptly between May and June approaching 

land surface by late spring or early summer. Annual waterlevel rises at this well are dependent on the distribution and 

timing of irrigation and not necessarily on the magnitude of 

the spring snowmelt runoff. The rapid water-level rise each 

year indicates a good hydraulic connection through a thin 

unsaturated zone and limited available storage in the aquifer, 

which agrees with conclusions from the reconnaissance 

reports published decades earlier (Eakin and Lamke, 1966, 

p. 31; Rush and Everett, 1966, p. 26–27).
14 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

tac08-4146_Figure 4

TenmileCreek

Tabor Creek

Starr Creek

South Fork

 Humboldt 

 River 

Marys River

Creek

Lamoille

Huntington

Creek

Dixie

Creek

Bishop Creek

Secret

Creek

Humboldt River

North Fork Humboldt

River

Diamond Mountains

Pinon Range

Ruby Mountains

Snake Mountains

Independence Mountains

Elko Hills

Peko

Hills

East Humboldt Range

Jarbidge Mountains

Adobe Range

South

Fork

Reservoir

Lamoille

Elko

Deeth

Carlin

Wells

3

4

1

2

8

7 9

1

5

6

116°30'W 116°W 115°30'W 115°W

41°30'N

41°N

40°30'N

40°N

EXPLANATION

Well and No. shown in figures 5–8.

Upper Humbolt River basin 

Humbolt River basin 

Base from U.S. Geological Survey digital data, 

1:250,000-scale, 2000. Universal Transverse 

Mercator projection, Zone 11. North American 

Datum of 1983. Shaded-relief base from 10-

meter Digital Elevation Model; sun illumination 

from northwest 45 degrees above horizon.

0 5 10 15 Miles 20

0 5 10 15 Kilometers 20

Figure 4. Selected wells where water levels have fluctuated, upper Humboldt River basin, northeastern Nevada.
Ground Water in the Upper Humboldt River Basin 15

Table 5. Lithologies penetrated by wells 1–9, upper Humboldt River basin, northeastern Nevada. 

[Well locations are shown in figure 4]

Well No. Nevada log

No.

Altitude

(feet)

Total depth

(feet)

Perforated interval

(feet)

Depth of top

(feet)

Lithology

penetrated

Thickness

(feet)

1* 76997 5,340 112 90–112 0 Topsoil 5

5 Sand and gravel 1

6 Clay 9

15 sand and gravel 13

28 Blue clay

2 23164 5,880 123 102–122 0 Soil 2

2 Gravel 33

35 Sandy Clay 65

100 Sand and gravel

4 28404 5,320 258 220–258 0 Topsoil 2

2 Sand and gravel 34

36 Sand and clay 27

63 Gravel 17

80 Sand and clay 92

172 Sand 18

190 Sand and clay 20

210 Sand 40

250 Sand and clay

5 13830 5,260 157 107–157 0 Soil 2

2 Sandy clay 8

10 Gravel and cobbles 16

26 Sand, gravel, clay 117

143 Gravel 1

144 Clay

6 30036 5,340 170 150–170 0 Soil 4

4 Green clay 23

27 Soft sandstone 118

145 Green clay 3

148 Sand

7 15700 5,240 510 128–510 0 Soil 4

4 Alluvium 106

110 Gravel 2

112 Volcanic rocks 66

178 Shale 77

255 Limestone 7

262 Fractured shale

8 9288 5,200 200 160–180 0 Gravel 15

15 Sandstone 5

20 Sandy clay 140

160 Sand and gravel 2

162 Rock and clay

9 11004 5,090 415 0 Clay and gravel 27

27 Gravel 4

31 Gravel and clay 27

58 Clay and gravel 42

100 Gravel 5

115 Clay and gravel 87

202 Gravel and clay 63

265 Gravel 7

272 Gravel and clay 33

305 Gravel 15

320 Sandy clay 27

347 Clay 15

362 Sandy clay

*

 No log is available for well 1. The log shown here is for a well about 500 feet to the west.
16 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

Well 3 is a stock well at the southwest side of the South 

Fork Area that has been measured annually by USGS since 

1964 (fig. 6A). Depth to water at this well ranged from about 

71 ft in 1984 and 1986 to 98 ft in 1995. Annual water levels in 

the well show multiyear periods of increasing and decreasing 

levels. Water levels rose 20 ft from 1970 to 1986, declined 

27 ft from 1986 to 1995, rose 16 ft from 1995 to 2001, and 

declined 16 ft by 2003 (fig. 6A). These periods of water-level 

rise and fall generally correspond to long-term variations 

in annual precipitation (fig. 6B). The water-level rise from 

1970 to 1984 was a 15-year period during which annual 

precipitation was 8 to 90 percent above average during 8 years 

and 5 to 50 percent below average during 7 years. However, 

the total amount of precipitation during above average years 

was about twice the amount during below average years. 

Overall, the 15-year period was one of well above average 

precipitation, and this explains the upward trend of water 

levels in the well during that period. Similarly, a severe 

and continuous drought from 1985 through 1994 (fig. 6B) 

coincides with the abrupt water-level decline from 1986 to 

1995 (fig. 6A). The water-level rise from 1995 to 2001 and 

its decline by 2003 also can be explained by the precipitation 

record, indicating that water levels in well 3 respond rapidly to 

variations in climate.

Filling of the South Fork Reservoir has resulted in waterlevel rises in basin-fill deposits over an area of uncertain 

extent. The Nevada Division of Water Resources began 

measuring water levels in wells in the vicinity of the South 

Fork Reservoir when filling began in December 1987. The 

time required for filling to a spillway elevation of 5,231 ft is 

not known and the stage of the reservoir probably fluctuates 

annually in response to runoff from the South Fork Area and 

Huntington Valley. Since 1988, water levels have risen 6 ft and 

8 ft at two wells about 3,000 ft and 1,000 ft, respectively, from 

the southwest side of the reservoir (wells 4 and 5 figs. 4 and 

7A–B). Both wells are adjacent to the flood plain of the South 

Fork Humboldt River and penetrate interbedded clay, sand, 

and gravel to depths of 144–250 ft (table 5). Water levels at a 

stock well about 1 mi northeast of the reservoir were at about 

89 ft through 1992, rose 2 ft in 1993, and fluctuated 1–2 ft 

through 1997 (well 6, figs. 4 and 7C). Water levels were not 

measured at the well again until 2005 when the depth to water 

was about 83 ft. Since then the water level has not changed. 

Although this well is at a higher altitude than the South Fork 

Reservoir, the well depth, at 170 ft (5,172 ft altitude), is 

below the reservoir elevation of 5,231 ft. In addition, this well 

penetrated interbedded clay and sand (table 5). Water-level 

rises at the wells 4, 5, and 6 are the result of infiltration of 

surface water during filling of the reservoir.

Figure 5. Water-level fluctuations at (A) wells near Deeth (well 1) and (B) Lamoille (well 2). See 

figure 4 for well locations.

tac08-4146_fig05

0 

5 

10 

15 

DEPTH TO WATER, IN FEET BELOW LAND SURFACE 

Well 1 

A. 

0 

5 

10 

15 

1945 1950 1955 1960 

Well 2 

B. 
Ground Water in the Upper Humboldt River Basin 17

tac08-4146_fig06

-100 

-80 

-60 

-40 

-20 

0 

20 

40 

60 

80 

100 

PERCENT DEPARTURE FROM AVERAGE

B. 

70 

80 

90 

100 

1965 1970 1975 1980 1985 1990 1995 2000 2005 

DEPTH TO WATER, IN FEET BELOW

LAND SURFACE 

A. 

Figure 6. (A) water-level fluctuation at well 3, 1965–2005 (fig. 4), and (B) annual 

precipitation as percent departure from average at Elko, Nevada, 1965–2005. Long-term 

(1947–2007) average is 9.6 inches per year.

Figure 7. Water-level fluctuations at wells 4, 5, and 6 near South Fork Reservoir, Elko, 

Nevada.

120 

122 

124 

126 

128 

130 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

Well 4 

A.

32 

34 

36 

38 

40 

42 

44 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

Well 5 

Well 6 

B. 

82 

84 

86 

88 

90 

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

C. 
18 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

100 

120 

140 

160 

180 

200 

220 

240 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

Well 7 

140 

160 

180 

200 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

Well 8 

Well 9 

50 

60 

70 

80 

90 

100 

110 

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 

DEPTH TO WATER, IN FEET 

BELOW LAND SURFACE 

A.

B. 

C. 

Figure 8. Water-level fluctuations at wells 7, 8, and 9 near Elko, Nevada.

Water levels also have risen at two wells on the northwest 

side of the group of hills that extends from the Elko Hills 

on the northeast to the north end of the Pinon Range on the 

southwest (wells 7 and 8, figs. 4 and 8A–B). These hills 

lie between the Humboldt River flood plain and the Dixie 

Creek-Tenmile Creek Area. The depth to water at well 7 rose 

from 225 ft in 1989 to 109 ft in 2008. This well was drilled in 

1976 and its log (well 7, table 5) indicates that it penetrated 

alluvium and gravel to 112 ft, volcanic rocks from 112 to 178 

ft, shale from 178 to 255 ft, limestone from 255 to 262 ft, 

and then faulted shale to a depth of 510 ft. The casing was 

perforated from 128 to 510 ft. The reason for the continuous 

water-level rise at this well is not clear because no nearby 

source of water is evident. One reason could be infiltration 

from the South Fork Reservoir into carbonate rocks, which are 

exposed in the canyon where the dam was constructed (pl. 1; 

Coats, 1987, pl. 1). However, the distance between the dam 

and well 7 is about 10 mi.

Water levels at well 8 rose from a depth of about 200 ft 

in 1989 to 145 ft by 2003 (fig. 8B). This well was drilled in 

1966 and its log (table 5) indicates that it penetrated gravel, 

clay, and sandstone to 162 ft and rock and clay from 162 to 

200 ft. The casing was perforated from 160 to 180 ft. Centerpivot irrigation and infiltration ponds for disposing of treated 

sewage, both constructed just west of this well in the early 

1990s, are the reason for the water-level rise. 

Pumping in the Elko Segment, especially for municipal 

purposes, probably has resulted in water-level declines. 

However, water-level monitoring has not been sufficient 

to identify the areal extent or magnitude of any declines. 

A secondary effect of municipal pumping can be that of 

water levels rising because of lawn watering in residential 

neighborhoods. The graph for well 9 (figs. 4 and 8C) indicates 

that water levels rose about 43 ft from 1988 through 2008. 

This well is next to a park and residential neighborhoods on 

the west side of Elko.
Summary 19

Summary

This report presents the results of a study of the water 

resources of the upper Humboldt River basin done in 2007–08 

by the U.S. Geological Survey in cooperation with Elko 

County. The report provides Elko County and State waterresource managers information needed to make informed 

decisions regarding future use and development of the groundwater resources of the basin. The overall objective of the 

report is to develop an improved understanding of the water 

resources of the upper Humboldt River basin. This report 

describes the hydrogeologic framework, and the occurrence 

and movement of ground water.

The upper Humboldt River basin covers an area of 

4,364 mi2 in northeastern Nevada, and consists of eight 

hydrographic areas—Marys River Area, Starr Valley 

Area, North Fork Area, Lamoille Valley, South Fork Area, 

Huntington Valley, Dixie Creek–Tenmile Creek Area, and 

the Elko Segment. These eight areas are the headwaters of 

the Humboldt River, and nearly all of the annual flow of the 

river in years of average flow originates in these areas. The 

main tributaries of the upper Humboldt River are South Fork 

Humboldt River, North Fork Humboldt River, Lamoille Creek, 

Marys River, and Bishop Creek. High flows during the spring 

and early summer are dominated by snowmelt runoff and low 

flows of late summer and autumn of each stream generally are 

sustained by ground-water discharge to the stream channel. 

The main exception is the lower reach of Marys River, which 

has no baseflow and goes dry every summer and autumn.

The upper Humboldt River basin consists of several 

deep structural basins in which basin-fill deposits of Tertiary 

and Quaternary age and volcanic rocks of Tertiary age 

have accumulated. The bedrock of each basin and adjacent 

mountains are composed of carbonate and clastic sedimentary 

rocks of Paleozoic age and crystalline rocks of Paleozoic, 

Mesozoic and Cenozoic age. The permeability of bedrock 

generally is very low except for carbonate rocks, which can be 

very permeable where circulating ground water has widened 

fractures through geologic time. The contrast in permeability 

of carbonate rocks with other bedrock is evident in the Ruby 

Mountains. Watersheds in the south end of the mountain 

range are underlain by carbonate rocks and are drained by 

ephemeral streams. Watersheds in central and northern parts of 

the mountain range are underlain by crystalline rocks and are 

drained by perennial streams. 

A thick sequence of alternating sedimentary deposits and 

volcanic rocks accumulated in basins of the study area from 

Eocene time to the present. The sequence consists of three 

hydrogeologic units—volcanic rocks, older basin-fill deposits, 

and younger basin-fill deposits. The composite thickness of 

the three units exceeds 5,000 ft in a deep narrow structural 

basin that extends from southern Huntington Valley to the 

northern Marys River Area parallel with the Ruby Mountains, 

East Humboldt Range, and Snake Mountains. Lithologic 

logs for oil exploration wells indicate that the older basin-fill 

deposits and volcanic rocks are commonly interbedded. In 

addition, older basin-fill deposits usually are tuffaceous and 

consist of interbedded fine-grained lake deposits and coarsegrained deposits of alluvial fans and stream flood plains. 

Younger basin-fill deposits consist mostly of unconsolidated 

sand and gravel along stream channels and as thin veneers 

covering older basin-fill deposits in the northern Marys River 

and North Fork Areas and in southern Huntington Valley. 

The principal aquifers in the upper Humboldt River basin 

are in basin-fill deposits. However, little is known regarding 

the hydraulic properties of these aquifers. Analysis of aquifer 

tests and well drillers’ logs would be very useful for making 

estimates of aquifer properties in the study area.

Ground water in the upper Humboldt River basin moves 

from recharge areas, which are along mountain fronts, and is 

discharged as seepage to stream channels, evapotranspiration, 

and pumpage. The main discharge area in the upper Humboldt 

River basin is the river flood plain, which can be as much as 

a mile wide. South of the Humboldt River, ground-water flow 

is from an extensive recharge area along the western base 

of the Ruby Mountains and East Humboldt Range and to a 

lesser extent the eastern base of the Diamond Mountains and 

Pinon Range. Flow generally is northward along the axes of 

Huntington Valley and the Dixie Creek–Tenmile Creek Area 

through a group of unnamed hills to the Humboldt River flood 

plain west of Elko. Ground-water flow in Lamoille Valley 

and Starr Valley Area is northwestward directly to the river 

flood plain. Water-level contours indicate that ground water 

discharges as seepage to stream channels in areas south of the 

river.

Ground-water flow in the Marys River Area is to the 

southwest from the Snake Mountains and south from other 

parts of the basin to the Humboldt River flood plain. Ground 

water does not discharge as seepage to the channel of the 

lower reaches of Marys River. 

The North Fork Area consists of two ground-water 

basins that are connected by streamflow. Sparse water-level 

data for the upper basin indicate that most ground-water 

flow is eastward from a recharge area along the base of the 

Independence Mountains. However, water-level data are not 

sufficient to determine the direction of ground-water flow 

in other parts of the upper basin. Ground-water flow in the 

lower part of the North Fork Area is eastward from the Adobe 

Range and westward from the Peko Hills toward the North 

Fork Humboldt River and then southward along the basin axis 

toward the Humboldt River flood plain.
20 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

Water-level contours indicate that the Humboldt River 

gains flow from ground-water seepage over its entire length in 

the study area. The contours show sharp upstream inflections 

where they cross the river and its flood plain from a few miles 

west of Wells to the west boundary of the study area. Groundwater flow in the Elko Segment is to the southeast from the 

Adobe Range and northwest from the Dixie Creek–Tenmile 

Creek Area through the unnamed hills between the Elko Hills 

and the South Fork Humboldt River. This reach of the river 

gains about 6,600 acre-ft/yr as ground-water seepage to the 

river channel. The estimated transmissivity of the aquifer in 

this flow section is 2,000 ft2/d.

Water levels in the upper Humboldt River basin fluctuate 

in response to the annual snowmelt runoff, to long-term 

variations in climate, and to human activities. From 1949 to 

1958, water levels at a well in the Marys River and Humboldt 

River flood plains near Deeth ranged from 8 to 11 ft below 

land surface in late winter to early spring, but rapidly rose 

to within several feet of land surface by early to late June. 

Annual water-level changes at a well near Lamoille were 

similar to those at the well near Deeth. The Lamoille well is 

about half a mile from the nearest stream, but it is in an area 

where streamflow diverted from Lamoille Creek is distributed 

to meadows and fields by a network of irrigation ditches. 

Water levels at the well ranged from 11 to 15 ft in early to late 

winter and rose abruptly to near land surface by late spring 

or early summer. Water-level rises at this well are dependent 

on the distribution and timing of irrigation and not on the 

magnitude of the spring snowmelt runoff.

Water-level changes at a stock well at the southwest side 

of the South Fork Area are believed to be related to variations 

in annual precipitation. Since 1970, water levels either rose 

or declined during four time periods ranging from a few to 

15 years. These periods correspond closely with periods of 

above or below average annual precipitation measured at Elko, 

and indicate that water levels in the well respond rapidly to 

variations in climate.

Filling of the South Fork Reservoir, which began in 1988, 

has resulted in water-level rises in the basin-fill deposits that 

underlie uplands on the east and west sides of the reservoir. 

Water level rises at another well, which is about 10 miles north 

of the reservoir, also could be the result of infiltration losses. 

Water-level rises at two wells west of Elko are the result of 

agricultural irrigation and infiltration of treated sewage and 

residential lawn watering, respectively. 

Acknowledgments

This study was done in cooperation with Elko County, 

and it is the result of discussions with, and input from, the 

Elko County Board of Commissioners and Elko County 

Water Planning Commission over several years. The author 

thanks well owners in the study area for providing USGS field 

personnel access to their wells. The author also thanks Alan 

Wallace with USGS in Reno for several helpful discussions 

regarding Cenozoic basins in northeastern Nevada.

References Cited

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of aquifers in intermontane basins of northern Nevada: 

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Commission of Subterranean Waters, Publication no. 64, p. 

197–212.

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.

Coats, R.R., 1987, Geology of Elko County, Nevada: Nevada 

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Dudley, W.W., Jr., 1967, Hydrogeology and ground-water flow 

system of the central Ruby Mountains, Nevada: Urbana, 

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22 Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada

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Publishing support provided by the U.S. Geological Survey Publishing 

Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the

Director, Nevada Water Science Center

U.S. Geological Survey

2730 N. Deer Run Road

Carson City, Nevada 89701

http://nv.water.usgs.gov
Plume— Hydrogeologic Framework and Occurrence and Movement of Ground Water, Upper Humboldt River Basin, Nevada—Scientific Investigations Report 2009–5014