Introduction

The U.S. Geological Survey (USGS) and the Bureau of Land Management (BLM) initiated a cooperative study through the Southern 

Nevada Public Land Management Act (Bureau of Land Management, 1998) to install six wells in the carbonate-rock and basin-fill aquifers of 

Clark County, Nevada, in areas of sparse groundwater data. This map uses water levels from these new wells, water levels from existing wells, 

and altitudes of spring discharge points to update a regional potentiometric map of the carbonate-rock aquifer and provide evidence to interpret 

the direction of regional groundwater flow. This potentiometric surface map is accompanied by drilling and borehole geophysical logs, wellconstruction information, lithology, water chemistry, and water levels from the newly drilled wells.

Carbonate-Rock Aquifer and Regional Groundwater Flow

The carbonate-rock aquifer in Clark County consists of thick sequences of Paleozoic-age limestone and dolomite with thinner beds 

of shale, sandstone, and quartzite that are deformed and extended. Mountain blocks of carbonate rock, separated by intermountain basins, 

thicken westward from the Muddy Mountains toward the Las Vegas and Sheep Ranges (Dettinger and others, 1995; Prudic and others, 1995; 

Harrill and Prudic, 1998; Heilweil and Brooks, 2011). Groundwater in the aquifer flows through fractures and faults associated with regional 

deformation and through small-scale brittle fractures. 

The aquifer is primarily recharged through fractures in high-precipitation areas that are in high-altitude mountain ranges near groundwater 

divides. Regional discharge is from springs and riparian areas at low altitudes in major drainage basins. Discharge from springs at the regional 

scale is generally constant and less transient than from springs discharging from more localized flow systems (Toth, 1963). Active groundwater 

withdrawals (or pumping) can affect local spring discharge, producing fluctuations not characteristic of discharge from natural regional springs. 

Parts of three groundwater flow systems compose the carbonate-rock aquifer in Clark County: (1) the Colorado System, (2) Death Valley 

System, and (3) Mesquite Valley System (Harrill and others, 1988). In Clark County, groundwater flow in the Colorado System is principally 

to the southeast, discharging at the headwaters to the Muddy River. Flow in the Death Valley System is principally to the west, discharging 

to springs in Amargosa Valley and Death Valley (Faunt and others, 2010). Localized flow in the Mesquite Valley System discharges by 

evapotranspiration from phreatophytes and evaporation on the valley playa (Glancy, 1968). 

Groundwater flow directions and gradients are presented on potentiometric maps by Bedinger and Harrill (2010) and Brooks and others 

(2014). Both studies used available groundwater levels, spring altitudes, and discharge data to classify groundwater and springs as regional 

or local. Bedinger and Harrill (2010) generalized hydrogeologic and geologic characteristics as proxy data to define regional hydraulic heads, 

which are described as water levels that are (1) lower than the water table in areas of recharge, (2) above the altitude of intermediate and 

regional discharge areas, and (3) below the altitude of non-discharging dry playas. 

Brooks and others (2014) developed a regional-scale numerical groundwater flow model to evaluate groundwater availability in the Great 

Basin. The published potentiometric contours, representative of the carbonate-rock aquifer, were based on water-level observations from wells 

completed in basin fill and carbonate rock. These studies were conducted at a regional scale and included relatively few direct observations 

from wells in Clark County, which are completed in carbonate rock.

Selected Existing Hydrogeologic Data

Water levels, water chemistry, lithology, and construction data from monitoring wells were compiled from the USGS National Water 

Information System (NWIS) database (U.S. Geological Survey, 2016) and from Thomas and others (1996), and compared to information 

obtained from the six new wells. Sites near production wells were excluded from this selection because of the potential for pumping related 

drawdown to affect water levels, and monitoring wells were excluded if screened across multiple intervals. Wells were selected if they were 

screened in the carbonate-rock aquifer or in the basin-fill aquifer at depths greater than 500 feet. It is assumed that basin-fill wells at this depth 

are in hydraulic connection with the carbonate-rock aquifer (Prudic and others, 1995). In Clark County, 24 wells completed in carbonate rock, 

28 wells completed in deep basin-fill deposits, and 5 springs were selected from the USGS NWIS database (table 1) and included in this report.

Table 2. Summary of well construction information for newly drilled wells in Clark County, Nevada.

[USGS, U.S. Geological Survey; NWIS, National Water Information System; ID, identifier; NDWR, Nevada Division of Water Resources; OD, outside dimension; DCR, depth to 

consolidated rock; WP, water production; gpm, amount of water pumped from well in gallons per minute; SCH, schedule; PVC, polyvinyl chloride; CR, carbonate rock; BF, basin 

fill; MR, mud rotary; AH, air hammer; >, greater than; —, no data; NA, not applicable]

Screened 

interval depth Well test data

Well name USGS NWIS

site ID

Map

ID

NDWR 

log ID

Hole 

depth 

(feet)

Well 

depth 

(feet)

Diameter 

of casing 

(OD), in 

inches

From 

(feet)

To 

(feet)

Casing 

material

DCR 

(feet)

Aquifer 

completion

Drilling 

method

WP 

(gpm)

Time 

(hours)

BW-01 364204114454501 A 109838 1,928 1,926 4.500 1,786 1,926 SCH 80 PVC 595 CR MR/

AH 3 to 5 24

LSC-01

362454115270201

B

112697 905 890 6.625

336 417 SCH 40 steel 65 CR MR 150 6

808 889

(nested) — — 210 2.250 190 210 SCH 80 PVC — BF MR 0

(dry)

0

(dry)

RB-01 362135114285401 C 113526 975 973 6.000 810 952 SCH 40 steel 755 CR MR/

AH >150 3

BUFPKTS-01 362352114414501 D 114409 1,200 1,198 4.500 988 1,198 SCH 40 steel 221 CR MR 20 10

IVPH-01 354849115225001 E 115275 1,295 1,290 4.500 1,065 1,275 SCH 40 steel 38 CR MR/

AH 30 10

JM-01 362901115220001 F 121811 1,103 1,080 4.500

200 300 SCH 40 steel

NA BF MR 50 to 

75 50

780 1,080 SCH 40 steel

Spontaneous potential (SP), natural gamma, caliper, and resistivity (borehole, 16- and 64-inch normal) wireline geophysical logs were 

obtained at each newly drilled borehole. The SP logs measure the voltage between the borehole and an electrode at the surface and are used 

to identify permeability changes and boundaries between formations at depth. Natural gamma logs show formation radiation intensity, which 

is generally higher for clay-rich rocks and sediments that tend to emit elevated levels of radiation from natural decay of uranium and thorium 

to potassium-40. Caliper logs measure borehole diameter and can indicate the presence of fractures along the borehole wall. Resistivity logs 

record the electrical resistivity of the formation and can indicate higher-porosity transmissive zones. These logs are used together to provide 

information on the subsurface geology. 

Drill cuttings (chips of broken geologic material brought to the surface by drilling fluids) were washed and analyzed. These cuttings, 

borehole geophysical data, and observations made during drilling provide an indication of the subsurface geologic characteristics at each new 

drill site. Borehole geophysical logs, drill penetration rate, and subsurface lithology are presented with the study area map. 

Wells were constructed of steel or polyvinyl chloride (PVC) well casing ranging from 4.5 to 6.625 inches in diameter. Vertically slotted 

screens were installed in water-bearing zones interpreted from borehole geophysics. A summary of well-construction information for each of 

the newly drilled wells is shown in table 2.

Figure 1. A, Total dissolved solids and major-ion concentrations in water samples collected from wells and springs associated with regional 

groundwater flow, and B, isotopic ratios of delta deuterium (δ2H) and delta oxygen-18 (δ18O) in samples collected from new and reference wells and 

springs in Clark County, Nevada (Global Meteoric Water Line [δ2H = 8×δ18O + 10; Craig, 1961], and Local Meteoric Water Line [δ2H = 6.5×δ18O – 9.7; 

Friedman and others, 1992]).

900–1,200 feet:

Sand pack (coarse sand)

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

1,200

988–1,198 feet:

Steel vertically slotted

 0.030-in. casing

551–800 feet:

Dark grey dolomitic

limestone

0–221 feet:

Surface alluvium

331–391 feet:

Sandstone

221–331 feet:

Light grey

fractured limestone

with clay

391–551 feet:

Light grey fractured

limestone with clay

800–1,200 feet:

 Sandstone

0–20 feet: 

Neat cement surface seal

20–900 feet:

Grout with bentonite 

plug (bottom) 

0–1,200 feet:

Hole diameter 9.875 in.

4.5-inch (in.)

steel casing

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

0

1,200

Depth, in feet below land surface

0 50 100 150 0 5 10 15 20 25 0 50 100 200 300 400 0 200 400 0 50 100 150 Missing record Missing record Missing record Missing record Sandstone

16-inch

normal

64-inch

normal

Unit change—

carbonate rock to 

sandstone

Unit change—

sand and gravel

to weathered 

carbonate rock

Unit change—

weathered carbonate

rock to consolidated 

carbonate rock

Water level

896 feet

(273.10 meters)

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

Well BUFPKTS-01 (362352114414501)

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

1,200

1,250

1,300

1,350

1,400

1,450

1,500

1,550

1,600

1,650

1,700

1,750

1,800

1,850

1,900

1,786–1,926 feet:

PVC vertically slotted

 0.020-in. casing

595–1,928 feet:

Fractured limestone

120–595 feet:

Weathered fractured

limestone

6–120 feet:

Reddish clean clay

0–6 feet:

Gravels, cobbles, sandy clay

4.5-inch (in.) schedule (SCH) 80

polyvinyl chloride (PVC)

casing

100–1,738 feet:

Bentonite grout

(≥30-percent solid slurry)

1,748–1,926 feet:

Gravel pack (coarse sand)

0–100 feet: 

Neat cement

0–98 feet:

Hole diameter 22 in.

Surface casing 15.4-in.-

diameter SCH 80 PVC

98–602 feet:

Hole diameter 12.75 in.

602–1,928 feet:

Hole diameter 8 in.

0–602 feet:

Surface casing 8.6-in.- 

diameter SCH 40 steel

[≥, greater than or equal to]

10-foot cement plug

Unit change—

decreased resistance

Clay-filled fracture

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

Well BW-01 (364204114454501)

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

1,200

1,250

1,300

1,350

1,400

1,450

1,500

1,550

1,600

1,650

1,700

1,750

1,800

1,850

1,900

0

1,950

Depth, in feet below land surface

0 200 400 600 0 5 10 15 20 25 0 100 200 300 −150 0 150 300 0 200 400 600 0 50 100 150

Decreased drill rate

Drilling method

changed from

mud rotary to

air hammer

Fracture?

Increased drill rate

Missing recordMissing record

16-inch

normal

64-inch

normal

Water level 418 feet

(127.41 meters)

Zone of clayfilled fractures 

FEET

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

1,200

1,250

1,300

Depth, in feet below land surface

Water level

905 feet

(275.84 meters) 

0–119 feet: 

Surface casing 10.75 in.

Neat cement surface seal

inside surface casing

4.5-inch (in.)

steel casing

0–119 feet:

Hole diameter 18 in.

0–37 feet:

Surface alluvium

37–38 feet:

Red clay

1,065–1,275 feet:

Steel vertically slotted

 0.030-in. casing

38–505 feet:

Red and grey 

fractured limestone

with clay

505–905 feet:

Light grey and white

fractured limestone

with clay

905–1,295 feet:

Light grey

fractured limestone

0–400 feet:

Bentonite chips

400–860 feet:

Bentonite grout

(≥30-percent solid slurry)

860–1,295 feet:

Gravel pack

119–1,295 feet: 

Hole diameter 10 in.

[≥, greater than or equal to]

Unit change—

sand and gravel

to fractured

carbonate rock

Clay-filled

fracture

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

Well IVPH-01 (354849115225001)

16-inch

normal

64-inch

normal

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

1,150

1,200

1,250

1,300

0

0 50 100 150 0 5 10 15 20 25 0 100 200 300 −250 0 250 500 0 1,000 0 15 30 45 60 Missing data due to surface power-line interference Missing data due to surface power-line interference Missing data due to surface power-line interference

Water level

598 feet

(181.36 meters) 

6.625-inch (in.)

steel casing

0–905 feet:

Hole diameter 12 in.

0 25 75 0 10 20 0 100 200 300

Depth, in feet below land surface

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

0

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

650 700 750 800

16-inch

normal

64-inch

normal

Missing record

MissingrecordMissingrecord

Zone of increased

clay content

100 500 1,000 1,500 0 50 100 150

Well LSC-01 (362454115270201)

Unit change—

density increase

Unit change—

sand and gravel

to carbonate rock

808–889 feet:

Steel vertically slotted

 0.030-in. casing

65–905 feet:

Fractured limestone

with clay

780–905 feet:

Sand pack

0–65 feet:

Surface alluvium

336–417 feet:

Steel vertically slotted

 0.030-in. casing

211–219 feet:

Bentonite chips plug

158–160 feet:

Bentonite chips plug

76–158 feet:

Grout 

160–211 feet:

Sand pack

219–450 feet:

Sand pack

450–780 feet:

Grout with cement

plug at top and

bottom

190–210 feet:

Polyvinyl chloride 

(PVC) vertically

slotted (0.020-in.)

casing

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

0–190 feet:

Consolidated and

unconsolidated

calcrete

Surface alluvium

190–675 feet:

Limestone, gravel,

sand, and clay

675–755 feet:

Dolomite, sandstone, and

reddish conglomerate

755–975 feet:

Dolomite

100–280 feet:

Bentonite grout hole plug

(≥30-percent solid slurry)

280–770 feet:

Grout with bentonite 

plug (bottom)

770–975 feet:

Sand pack

810–952 feet:

Steel vertically slotted

 0.030-in. casing

0–100 feet:

Neat cement surface seal

100–975 feet:

Hole diameter 11.5 in.

6-inch (in.)

steel casing 0–72 feet:

Hole diameter 20 in.

72–100 feet:

Hole diameter 15.75 in.

[≥, greater than or equal to]

975

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

0

Depth, in feet below land surface

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

Well RB-01 (362135114285401)

0 100 200 0 5 10 15 20 25 0 30 60 0 200 400 0 100 200 0 50 100 150 Missing record Missing record Missing record Missing record Zone of clay-filled fractures Less certain

Water level

277 feet

(84.43 meters)

Unit change—density

increase, carbonate 

rock contact?

Drilling method changed

from mud rotary to air

hammer

Unit change—alluvium

to carbonate rock

16-inch

normal

64-inch

normal

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

Bureau of Land Management

Scientific Investigations Map 3434

Drilling, Construction, Water Chemistry, Water Levels, and Regional Potentiometric Surface of the Upper Carbonate-Rock Aquifer in Clark County, Nevada, 2009–2015

By

Jon W. Wilson

2019

A

B

A

C

D

Mesquite

Henderson

Las Vegas

Moapa

Valley

Boulder

City

Indian

Springs

North

Las Vegas

40

2,120

35

2,420

31

2,423

28

3,062

26

3,083

23

1,831

22

1,819

19

1,820

17

4,794

16

1,811

9

2,150

2

3,146

1

3,484

39

1,820

32

2,499

30

3,318

27

2,898

24

1,822

4

1,820

6

1,819

21

1,819

20

8,500

15

2,856

13

1,819

12

2,760

8

1,819

7

2,891

49

3,288

48

2,119

47

1,845

46

2,085

45

1,806

43

1,691

42

2,354

41

2,005

38

2,376

37

1,813

36

1,683

34

2,077

33

2,160

29

3,067

25

2,823

18

2,048

14

2,381

11

1,815

5

3,917

3

1,815

56

1,811

51

1,573

50

1,574 52

1,341

55

2,930

F

3,011

E

2,507

D

1,749

C

1,644

B

2,843

A

1,814

CLARK

CO

LINCOLN

CO

SAN BERNARDINO CO

NYE

CO

INYO CO

NEVADA

ARIZONA

NEVADA

CALIFORNIA

Death Valley

System

Mesquite

Valley

System

Colorado

System

Las Vegas

Rang

e

To Death Valley

(68 miles)

Spring

Mountains

Lake Mead

ARIZONA

NEVADA

36°30'

36°00'

35°30'

116°00' 115°30' 115°00' 114°30' 114°00'

54

1,562

53

1,576

115°30' 115°00' 114°30' 114°00'

36°30'

36°00'

35°30'

44

2,150

10

1,810

S

heep

Range

Las Vegas Wash

Muddy River

Virgin River

Muddy

Mountains

To Amargosa

 Valley (16 miles)

Las Vegas

Valley

MOHAVE

CO

MOHAVE

CO

CLARK

CO

57

6,324

Lake

Las Vegas

EXPLANATION

Carbonate-rock province (Schaefer and others, 2005)

Paleozoic carbonate rock (Harrill and Prudic, 1998)

Area discussed in text with identifier

Major flow system boundary (Harrill and others, 1988)

Water-level altitude, in feet. Contour interval is 250 feet; 

dashed where uncertain. Vertical datum is National 

Geodetic Vertical Datum of 1929.

Location of springs and water-level observation wells—Top

number is the map identifier and bottom number is the altitude 

of the water surface above mean sea level from table 1.

New water-level observation point 

Reference well completed in carbonate rock

Reference well completed in basin fill

Spring

7

2,891

55

2,930

33

2,160

F

3,011

A

NEVADA

UTAH

CALIFORNIA

ARIZONA

OREGON IDAHO

Study

area

10 0 10 20 30 40 50 KILOMETERS

SCALE 1: 500,000

10 0 10 20 30 40 MILES

Base modified from U.S. Geological Survey and other Federal 

digital data, various scales; Universal Transverse Mercator 

projection, zone 11; North American Datum of 1983; National 

Geodetic Vertical Datum of 1929 

2,500

2,750

1,500

2,000

1,750

3,000

3,250

3,500

4,000 3,750

2,750

2,000

2,500

3,000

0–100 feet:

Bentonite grout

(≥30-percent solid 

slurry)

100–480 feet:

Sand pack

(coarse sand)

480–680 feet:

Bentonite grout

(≥30-percent solid

slurry)

680–1,103 feet:

Sand pack 

780–1,080 feet: (coarse sand)

Steel vertically slotted

 0.030-in. casing

200–300 feet:

Steel vertically slotted

 0.030-in. casing

0–1,103 feet:

Alluvial material (subangular 

to sub-rounded cobbles and 

gravels of carbonate rock)

0–200 feet:

Steel casing

4.5-inch (in.)

steel casing

[≥, greater than or equal to]

0–500 feet:

Hole diameter 

10.625 in.

500–1,103 feet:

Hole diameter 

9.875 in.

Water level

243 feet

(74.07 meters)

Transition—

consolidated

sediments

Depth, in feet below land surface

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

0

1,100

Spontaneous 

potential,

in millivolts

Single point 

resistance,

in ohms

Caliper, hole

diameter,

in inches

Penetration rate,

in minutes

Natural gamma, in

counts per second

Resistivity,

in ohm-meters

0 16 −50 0 50 0 50 100 150 0 30 60 90 120 Less permeable unit

Well JM-01 (362901115220001)

8 0 40 80

64-inch

normal

16-inch

normal

0 40 80 120

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1,000

1,050

1,100

4 12 20 60 −25 25

Variations in borehole direction during drilling (drift) are common and can require corrections 

to water-level measurements. Borehole drift was monitored, and deviation was measured where drift 

was detected during the drilling of all new wells. The borehole at well BUFPKTS–01 was the only 

site that needed correction because borehole drift occurred above the depth of the static water level. 

The water level for this well was corrected using the equation from Elliott and Fenelon (2010):

where

Vd is the corrected vertical depth,

Md is the measured depth,

M

top is the measured depth to the top of the correction interval,

ΔVint is the difference in the true vertical depth between the top and bottom of the 

correction interval,

ΔMint is the difference in the measured top and bottom of the correction interval, and

Vtop is the corrected vertical depth to the top of the interval over which the correction 

applies.

Regional Potentiometric Surface

Groundwater levels from the six wells drilled for this project and wells fitting the criteria 

described in the section “Selected Existing Hydrogeologic Data,” were compiled and used to 

construct a groundwater-level map representing the regional potentiometric surface of the upper 

carbonate-rock aquifer in Clark County, Nevada, in 2009–2015. Data used to construct the 

potentiometric surface are published separately as a USGS data release (Wilson, 2019). This map 

is similar to the regional potentiometric surface shown on previous maps by Bedinger and Harrill 

(2010) and Brooks and others (2014). In general, the potentiometric surface on this map follows the 

overlying land-surface topography. Higher topographic altitudes typically have higher groundwater 

altitudes, hydraulic gradients generally are steep near mountain ranges and low (flatten) in basins, and 

water-level contours parallel and intersect surface-water features.

Area on map Description

A In the Las Vegas and Sheep Ranges, and the Spring Mountains, mountain 

block recharge contributes to and directs regional groundwater flow in 

Clark County. 

B Water-level contours generally indicate groundwater flow to the east, 

terminating at discharge points along the Las Vegas Wash in Las Vegas 

Valley, and the Muddy River near Moapa Valley.

C A low water-level gradient near Moapa Valley indicates slow groundwater 

movement toward the Muddy River and Lake Mead.

D A low water-level gradient in northeast Clark County indicates that 

groundwater in this area flows toward the Virgin River.

Summary and Conclusions

During 2009 and 2015, the U.S. Geological Survey in cooperation with the Bureau of Land 

Management installed six new wells in Clark County, Nevada. The wells were installed to address the 

spatial gaps of wells completed in the carbonate-rock aquifer. This map describes new and existing 

water-level and hydrologic data used to (1) develop a potentiometric map, and (2) provide additional 

supporting evidence for the direction of regional groundwater flow in the upper carbonate-rock 

aquifer in Clark County. Results from this study indicate that the Spring Mountains and the Las Vegas 

and Sheep Ranges provide primary recharge to the groundwater system in western Clark County. 

Additionally, potentiometric contours indicate eastward groundwater flow in much of Clark County 

that terminates at springs along Las Vegas Wash, the Muddy River, and the Virgin River. Previous 

maps by Bedinger and Harrill (2010) and Brooks and others (2014) show similar water-surface 

altitudes and gradients. This study introduces new water-level measurement sites that cover data gaps 

and support previous regional water-surface interpretations. Additionally, comparison of lithologic 

descriptions, geophysical logs, and groundwater chemistry from the six wells drilled during this study 

to existing data, substantiates that water levels in the new wells represent the regional carbonate-rock 

aquifer. 

References Cited

Bedinger, M.S., and Harrill, J.R., 2010, Appendix 1: Regional potential for interbasin flow of 

groundwater, in Belcher, W.R., and Sweetkind, D.S., eds., Death Valley regional groundwater flow 

system, Nevada and California—Hydrogeologic framework and transient groundwater flow model: 

U.S. Geological Survey Professional Paper 1711, p. 345–364, https://pubs.usgs.gov/pp/1711/.

Brooks, L.E., Masbruch, M.D., Sweetkind, D.S., and Buto, S.G., 2014, Steady-state numerical 

groundwater flow model of the Great Basin carbonate and alluvial aquifer system: U.S. Geological 

Survey Scientific Investigations Report 2014–5213, 124 p., https://pubs.usgs.gov/sir/2014/5213/. 

Bureau of Land Management, 1998, Southern Nevada Public Land Management Act of 1998—Public 

Law 105–263: Bureau of Land Management, https://www.gpo.gov/fdsys/pkg/PLAW-105publ263/

pdf/PLAW-105publ263.pdf.

Craig, H., 1961, Isotopic variations in meteoric waters: Science, v. 133, no. 3465, p. 1702–1703, 

http://www.jstor.org/stable/1708089?origin=JSTOR-pdf.

Dettinger, M.D., Harrill, J.R., Schmidt, D.L., and Hess, J.W., 1995, Distribution of carbonate-rock 

aquifers and the potential for their development, southern Nevada and adjacent parts of California, 

Arizona, and Utah: U.S. Geological Survey Water-Resources Investigations Report 91–4146, 100 p., 

2 pl., https://pubs.er.usgs.gov/publication/wri914146.

Elliott, P.E., and Fenelon, J.M., 2010, Database of groundwater levels and hydrograph descriptions for 

the Nevada Test Site area, Nye County, Nevada (ver. 9.0, February 2019): U.S. Geological Survey 

Data Series 533, 13 p., https://doi.org/10.3133/ds533. 

Faunt, C.C., D’Agnese, F.A., and O’Brien, G.M., 2010, Hydrology, chap. D in Belcher, W.R., and 

Sweetkind, D.S., eds., Death Valley regional groundwater flow system, Nevada and California— 

Hydrogeologic framework and transient groundwater flow model: U.S. Geological Survey 

Professional Paper 1711, p. 133–159, https://pubs.usgs.gov/pp/1711/. 

Friedman, I., Smith, G.I., Gleason, J.D., Warden, A., and Harris, J.M., 1992, Stable isotope 

composition of waters in southeastern California—1. Modern precipitation: Journal of Geophysical 

Research—Atmospheres, v. 97, no. D5, p. 5795–5812, https://agupubs.onlinelibrary.wiley.com/doi/

abs/10.1029/92JD00184.

Glancy, P.A., 1968, Water-resources appraisal of Mesquite–Ivanpah Valley area, Nevada and 

California: Nevada Department of Conservation and Natural Resources, Groundwater Resources 

Reconnaissance Series Report 46, 57 p. 

Harrill, J.R., Gates, J.S., and Thomas, J.M., 1988, Major ground-water flow systems in the Great Basin 

region of Nevada, Utah, and adjacent states: U.S. Geological Survey Hydrologic Investigations Atlas 

HA-694-C, 2 sheets, scale 1:1,000,000, https://doi.org/10.3133/ha694C.

Harrill, J.R., and Prudic, D.E., 1998, Aquifer systems in the Great Basin region of Nevada, Utah, and 

adjacent states—Summary report: U.S. Geological Survey Professional Paper 1409–A, 66 p., 

https://pubs.usgs.gov/pp/1409a/report.pdf. 

Heilweil, V.M., and Brooks, L.E., eds., 2011, Conceptual model of the Great Basin carbonate and 

alluvial aquifer system: U.S. Geological Survey Scientific Investigations Report 2010–5193, 191 p., 

https://pubs.usgs.gov/sir/2010/5193/. 

Prudic, D.E., Harrill, J.R., and Burbey, T.J., 1995, Conceptual evaluation of regional ground-water 

flow in the carbonate-rock province of the Great Basin, Nevada, Utah, and adjacent states: U.S. 

Geological Survey Professional Paper 1409–D, 102 p., https://pubs.er.usgs.gov/publication/pp1409D. 

Schaefer, D.H., Thiros, S.A., and Rosen, M.R., 2005, Ground-water quality in the carbonate-rock 

aquifer of the Great Basin, Nevada and Utah, 2003: U.S. Geological Survey Scientific Investigations 

Report 2005–5232, 41 p., https://pubs.usgs.gov/sir/2005/5232/.

Thomas, J.M., Welch, A.H., and Dettinger, M.D., 1996, Geochemistry and isotope hydrology of 

representative aquifers in the Great Basin region of Nevada, Utah, and adjacent states: U.S. 

Geological Survey Professional Paper 1409–C, 100 p., https://pubs.er.usgs.gov/publication/pp1409C.

Toth, J., 1963, A theoretical analysis of groundwater flow in small drainage basins: Journal of 

Geophysical Research, v. 68, no. 16, p. 4795–4812, https://agupubs.onlinelibrary.wiley.com/

doi/10.1029/JZ068i016p04795.

U.S. Geological Survey (USGS), 2016, USGS water data for the Nation: U.S. Geological Survey 

National Water Information System database, accessed January 2016, at https://doi.org/10.5066/

F7P55KJN.

Wilson, J.W., 2019, Supplemental data for drilling, construction, water chemistry, water levels, and 

regional potentiometric surface of the upper carbonate-rock aquifer in Clark County, Nevada, 

2009–2015: U.S. Geological Survey data release, https://doi.org/10.5066/P9K73T7Q.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

This map or plate is offered as an online-only, digital publication. Users should be aware that because of differences 

in rendering processes and pixel resolution, some slight distortion of scale may occur when viewing it on a computer 

screen or when printing it on an electronic plotter, even when it is viewed or printed at its intended publication scale.

Digital files available at https://doi.org/10.3133/sim3434 or https://pubs.usgs.gov/sim/3434/.

Suggested citation: Wilson, J.W., 2019, Drilling, construction, water chemistry, water levels, and regional 

potentiometric surface of the upper carbonate-rock aquifer in Clark County, Nevada, 2009–2015: U.S. Geological Survey 

Scientific Investigations Map 3434, scale 1:500,000, https://doi.org/10.3133/sim3434.

ISSN 2329-132X (online)

https://doi.org/10.3133/sim3434

Table 3. Total dissolved solids and concentrations of major ions in water samples collected from new wells in Clark County, Nevada.

[mm/dd/yyyy, month/day/year; mg/L, milligrams per liter; <, less than; CR, carbonate rock; BF, basin fill]

Well name Date 

(mm/dd/yyyy)

Total 

dissolved

solids 

(mg/L)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium 

(mg/L)

Chloride 

(mg/L)

Sulfate 

(mg/L)

Carbonate 

(mg/L)

Bicarbonate 

(mg/L)

Principal 

contributing 

aquifer

BW-01 04/30/2010 616 60.8 24.4 101 11.0 56.3 195 < 1.0 264 CR

LSC-01 06/14/2012 249 45.1 28.2 5.0 1.46 2.90 21.4 < 1.0 246 CR

RB-01 04/09/2014 2,980 399 135 272 18.5 312 1,570 < 1.0 145 CR

BUFPKTS-01 04/10/2014 234 7.6 4.8 72.4 5.68 17.9 20.6 8.4 166 CR

IVPH-01 04/11/2014 499 67.1 38.2 53.9 3.33 105 86.4 < 1.0 210 CR

JM-01 03/14/2013 283 35.7 28.5 33.4 1.82 5.85 19.0 < 1.0 299 BF

Table 4. Isotopic ratios of deuterium (δ2H) and oxygen 

(δ18O) in water samples collected from new wells drilled 

in Clark County, Nevada.

[δ2H, deuterium (2H) to protium (1H) isotopic ratio relative to 

VSMOW; δ18O, oxygen-18 to oxygen-16 isotopic ratio relative to 

VSMOW; VSMOW, Vienna Standard Mean Ocean Water; ‰, per 

mil (parts per thousand)]

Well name δ2

H

(‰)

δ18O

(‰)

BW-01 –97.49 –12.89

LSC-01 –103.00 –13.98

RB-01 –91.70 –12.38

BUFPKTS-01 –82.50 –11.26

IVPH-01 –92.30 –12.71

JM-01 –95.67 –13.01

(1)

Table 1. Existing monitoring wells representative of the carbonate-rock and basin-fill aquifers in Clark County, Nevada.

 [ID, identifier; USGS, U.S. Geological Survey; NWIS, National Water Information System; mm/dd/yyyy, month/day/year; NGVD 29, National Geodetic Vertical Datum of 

1929; CR, carbonate rock; BF, basin fill; —, no data]

Map 

ID USGS site ID USGS NWIS site name Site type

Well 

depth 

(feet)

Hole 

depth 

(feet)

Contributing 

aquifer 

Date of 

water-level 

measurement 

(mm/dd/yyyy)

Water 

level, 

in feet 

below 

land 

surface

Water-level 

altitude, 

in feet 

above mean 

sea level 

(NGVD 29)

1 361816115241301 212 S19 E59 18AAC 1 Well 542 542 CR 09/01/1964 417.00 3,484

2 363500115400001 161 S16 E56 16 1 Indian Springs 

Sewage Co

Well 550 590 CR 06/01/1963 54.00 3,146

3 362846114495501 216 S17 E64 09DDCD1 CRYSTAL 2 Well 565 565 CR 08/21/2000 254.94 1,815

4 364741114532801 210 S13 E63 26AAAA1 USGS-MX 

CE-DT-5

Well 628 628 CR 08/13/1999 349.81 1,820

5 360016115361501 163 S22 E57 29DABC1 USBLM 

NDOT 01

Well 660 660 CR 09/07/2010 306.15 3,917

6 364743114533101 210 S13 E63 23DDDC1 USGS-MX 

CE-DT-4

Well 669 669 CR 10/15/2015 356.27 1,819

7 363212115240301 212 S16 E58 23DDD 1 USFWS SBH-1 Well 720 720 CR 05/28/2015 575.20 2,891

8 362531114524201 216 S18 E64 07BB 1 WELL (REPORT 

R50)

Well 793 793 CR 11/29/1956 226.40 1,819

9 355829115150601 212 S23 E60 03DBCB1 TORTOISE 

CENTER

Well 800 800 CR 03/19/1990 555.00 2,150

10 361736114531601 215 S19 E63 13DCAA1 EBM-3 Well 900 1,241 CR 02/20/2004 578.73 1,810

11 363308114553001 217 S16 E63 09DDAB1 USBLM 

SHV-1

Well 920 920 CR 10/01/2015 833.69 1,815

12 363332115244001 212 S16 E58 14A 1 USFWS DR-1 Well 930 960 CR 05/28/2015 813.40 2,760

13 364604114471301 219 S13 E64 35DCAD1 USGS-MX 

CE-DT-6

Well 937 937 CR 11/01/2002 456.00 1,819

14 364830115512601 160 S13 E55 19 1 TW- 3 Well 1,127 1,860 CR 08/25/2015 1,103.00 2,381

15 363407115215301 212 S16 E59 08 2 USGS - Cow Camp Well 1,403 1,403 CR 07/29/2015 1,330.30 2,856

16 362507114572701 216 S18 E63 05AADB1 Well 1,979 2,007 CR 03/01/2002 755.00 1,811

17 360946115421401 162 S20 E56 33CCAA1 TROUT 

CANYON 01

Well 718.5 720 CR 01/05/2015 467.30 4,794

18 364451114585001 210 S14 E62 01ADBD1 CSVM-5 Well 1,780 1,783 CR 09/20/2011 1,081.20 2,048

19 362700114564401 216 S17 E63 21DCCC1 HV-1 Well 2,480 2,480 CR 06/20/2000 882.00 1,820

20 361811115404401 212 S19 E56 15ABBD1 Well 660 660 CR 01/26/1981 214.40 8,500

21 364738114534001 210 S13 E63 26AABD1 CSV-RW-2 Well 710 720 CR 09/14/2011 383.40 1,819

22 364728114531001 210 S13 E63 25BDBB1 CSVM-1 Well 1,040 1,060 CR 09/21/2011 341.90 1,819

23 364529114492401 219 S13HE64 33DBBC1 UMVM-1 Well 1,200 1,200 CR 04/22/2003 247.00 1,831

24 363943114552301 210 S15 E63 03BBCC1 CSVM-2 Well 1,400 1,425 CR 09/20/2011 750.70 1,822

25 360201115204701 212 S22 E59 15DAAB1 Well 532 532 BF 03/14/1990 267.21 2,823

26 363201115333801 211 S16 E57 28B 1 Hwy95 Cons 1 Well 550 550 BF 04/22/1963 98.00 3,083

27 360247115224401 212 S22 E59 09CBDB1 HUMANE Well 570 570 BF 01/21/2009 354.80 2,898

28 363452115405101 161 S16 E56 08BAAC1 USAF Well 3 Well 600 600 BF 07/29/2015 68.00 3,062

29 363447115404601 161 S16 E56 08BAAD1 USAF Well 

106-2

Well 604 604 BF 07/29/2015 63.15 3,067

30 363255115515801 161 S16 E54 24BCBA1 Army 2 Well 627 658 BF 08/17/2015 495.20 3,318

31 355015115102601 166 S24 E61 20DDAC1 HIDDEN 

VALLEY

Well 640 640 BF 12/03/1956 605.00 2,423

32 354454115205401 164A S25 E59 27AACA1 JAIRPORT Well 650 650 BF 12/11/2008 280.90 2,499

33 361136115101401 212 S23 E61 03BCC 1 Sky Harbor 

Airport

Well 650 650 BF 04/18/2011 215.36 2,160

34 360941115104801 212 S20 E61 32CDC 1 Well 665 665 BF 04/18/2011 18.47 2,077

35 355923115174201 212 S22 E60 32CB 1 Well 700 700 BF 08/06/1979 460.00 2,420

36 360826115020001 212 S21 E62 10ACAA1 Nevada Power 

Company

Well 715 715 BF 04/20/2011 21.94 1,683

37 364601114514301 210 S13 E64 31DADA1 USGS CSV-1 Well 765 765 BF 07/31/2009 346.91 1,813

38 361939115154801 212 S19 E60 04DAB 2 NV Division of 

Forestry

Well 780 780 BF 04/21/2011 77.51 2,376

39 364127114553001 210 S14 E63 28AACD1 USGS CSV-3 Well 780 780 BF 09/20/2011 594.00 1,820

40 355947115163501 212 S22 E60 33BB 1 Well 785 785 BF 12/10/1976 585.00 2,120

41 360931115083802 212 S21 E61 03ABB 2 Well 807 807 BF 04/18/2011 9.08 2,005

42 361843115161001 212 S19 E60 09BCC 1 Well 830 830 BF 04/28/2011 155.76 2,354

43 361233115021501 212 S20 E62 15BBAB1 USAF Nellis 

12 (C)

Well 1,000 1,000 BF 04/27/2011 124.71 1,691

44 361346115115901 212 S20 E61 06CBDD1 CNLV Desert 

Aire

Well 1,000 1,000 BF 04/27/2011 60.72 2,150

45 361400115040901 212 S20 E62 05CAAA1 CNLV Wilshire Well 1,000 1,000 BF 10/01/2015 62.56 1,806

46 361303115140301 212 S20 E60 11CAAA1 LVVWD W028 Well 1,003 1,003 BF 01/18/2007 202.05 2,085

47 361232115061001 212 S20 E61 13ABDB1 CNLV Diana 

Terrace

Well 1,230 1,230 BF 10/01/2015 11.83 1,845

48 361626115090701 212 S19 E61 21DDB 1 CNLV Regional 

Park 1

Well 1,300 1,300 BF 09/01/2015 40.72 2,119

49 360809115252601 212 S21 E58 12DDDD1 RED ROCK 

WASH

Well 503 503 BF 11/07/2008 400.54 3,288

50 364014114315301 220 S14 E67 31DACD1 Well 387 620 BF 03/19/1987 116.00 1,574

51 364912114041201 222 S13 E71 09BDCA1 PS27 Well 1,450 1,493 BF 07/08/1994 84.00 1,573

52 364044114165201 222 S14 E69 33ABC 1 D & HA Well 880 880 BF 03/10/1985 37.26 1,341

53 362239114263501 215 S18 E67 12DDAD1 ROGERS 

SPRING

Spring — — CR — — 1,576

54 362321114252601 215 S18 E68 07ABBA1 BLUE POINT 

SPRING

Spring — — CR — — 1,562

55 09419625 CORN CK SPGS AT NATIONAL FISH & 

WILDLIFE HDQRS, NV

Spring — — CR — — 2,930

56 09415910 PEDERSON SPGS NR MOAPA, NV Spring — — CR — — 1,811

57 362450115442001 161 S18 E55 01DACC1 COLD CREEK 

SPRING

Spring — — CR — — 6,324

Water Chemistry

Water-quality samples for major-ion chemistry and the stable isotopes of water 

(deuterium, δ2H, and oxygen, δ18O) were collected at each new well site, and results 

of analysis were compared to existing values from springs and wells near the drill 

sites. Total dissolved solids (TDS) and concentrations of calcium (Ca), magnesium 

(Mg), sodium (Na), potassium (K), chloride (Cl), sulfate (SO4), carbonate (CO3), 

and bicarbonate (HCO3) were measured by the USGS National Water Quality 

Laboratory (NWQL), in Denver, Colorado (table 3). Deuterium (δ2H) and oxygen 

(δ18O) isotopes were analyzed by the USGS Radiogenic Isotope Facility in Denver, 

Colorado (table 4).

Standard three-well-casing volumes were purged from each well, and water 

samples were collected with a submersible pump except at two sites (wells 

IVPH–01 and BUFPKTS–01) where samples were obtained through bailing. 

A 20-foot-long bailer was used to purge water from the well and collect a 

representative water sample. 

CATIONS ANIONS

Sulfate (SO4

) + Chloride (Cl)

Calcium (Ca) + Magnesium (Mg)

Carbonate (CO3

) + Bicarbonate (HCO3

)

Sodium (Na) + Potassium (K)

Sulfate (SO4

)

Magnesium (Mg)

20 40 60 80

80

60

40

20

20

40

60

80

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

Calcium (Ca) Chloride (Cl)

Percent milliequivalent per liter

20

40

60

80

A 100

B

4,000

3,000

2,000

1,000

Total dissolved solids,

in milligrams per liter 0 0

100

80 60 40 20

20

40

60

80

Local Meteoric Water Line

Global Meteoric Water Line

Less enriched high-altitude recharge

More enriched low-altitude recharge

−14.0 −13.5 −13.0 −12.5 −12.0 −11.5 −11.0 −10.5 −10.0

Delta oxygen-18, in per mil

Delta deuterium, in per mil

−70

−75

−80

−85

−90

−95

−100

−105

−110

EXPLANATION

BUFPKTS-01

IVPH-01

JM-01

BW-01

LSC-01

RB-01

Rogers Spring

Blue Point Spring

Corn Creek Spring

Pederson Spring

Cold Creek Spring

CSV-2 well

CSV-3 well

MX-4 well

MX-6 well

Corn Creek well

Existing sites (Thomas and others, 1996)

New wells

Major-ion chemistry is important to an understanding of the migration of water through a groundwater flow system. A Piper diagram 

(fig. 1A) can be used to evaluate the chemical characteristics of groundwater and the effects of chemical processes occurring between minerals 

and water. Groundwater samples from newly drilled wells show similar major-ion chemistry to previously sampled wells and springs (Thomas 

and others, 1996) that are assumed to represent groundwater from the regional carbonate-rock aquifer. 

Isotopic ratios of δ2H and δ18O in water samples collected from wells drilled for this study and in samples previously collected from wells 

and springs, are compared to the Global Meteoric Water Line (GMWL) and a Local Meteoric Water Line (LMWL) on figure 1B. This plot 

provides a comparison of recharge from low-altitude and high-altitude precipitation sources to waters from previously published data (Thomas 

and others, 1996).

Water-Level Information

Water levels from newly drilled wells were measured periodically from 2009 to 2015 and stored in the USGS NWIS database 

(https://waterdata.usgs.gov/nwis). These data were quality assured, which included evaluating measurements for temporal irregularity and 

adjustments due to known borehole deviation. Water levels were relatively stable throughout the duration of this project except for well BW-01, 

which experienced a decline of approximately 3 feet from January 2010 to May 2013, and a subsequent recovery of approximately 1 foot from 

June 2013 to June 2014.

V M M V

M d d top V int

int

    top





 



 





V M d d  0. . 993 3 45 (2)

Drilling, Borehole Geophysical Logs, Lithology, and Well Construction

Groundwater monitoring wells were installed at six locations in Clark County. Criteria for selecting drill sites included (1) the carbonaterock aquifer was relatively close to the surface, (2) there were no nearby groundwater withdrawals, and (3) access for drilling equipment was 

possible on existing roads. 

Drilling techniques were dependent upon borehole advancement rate and lithology. Mud rotary drilling was predominantly used 

when drilling through unconsolidated material consisting mostly of sand, gravel, and cobbles. At all sites, the drill penetration rate through 

unconsolidated material was relatively consistent and progressed rapidly with this technique. When penetration rate slowed in denser rock 

units, air-hammer drilling was used. A change in drilling method allowed for consistent downward progress and limited drill time and cost.