U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

Llano Estacado Underground Water Conservation District, 

Sandy Land Underground Water Conservation District, and South Plains Underground Water Conservation District

Scientific Investigations Map 3355

Sheet 1 of 2

laf16-0739_fig 03

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

380

385

385

380

62

62

82

180

214

137

83

214

3,500

3,460

3,380

3,640

3,400

3,520

3,440

3,420

3,540

3,620

3,560

2,980

3,600

2,960

3,580

3,000

3,020

3,680

3,660

3,060

3,080

3,100

3,120

3,140

3,160

3,480

3,360

3,180

3,200

3,340

3,260

3,320

3,300

3,280

3,220

3,100

3,720

3,700

3,240

3,040

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES

COUNTY

HOCKLEY

COUNTY

TERRY

COUNTY

YOAKUM

COUNTY

EXPLANATION

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

Groundwater-level altitude, in feet above

North American Vertical Datum of 1988 (NAVD 88)

3,747

2,870

Potentiometric contour

Shows altitude at which water level would have stood in tightly

cased wells. Dashed where approximately located. Contour

interval is 20 feet. Datum is NAVD 88

Groundwater flow path (dashed where approximately located)

Edwards-Trinity aquifer downdip extent

Location of groundwater-level measurement well

3,500

0 5 10 15 MILES

0 5 10 15 KILOMETERS

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13 TEXAS

NEW MEXICO

Gaines, Terry, and Yoakum Counties, Texas.

Figure 4. Mean early development period (1930–60) groundwater-level-altitude grid for the Ogallala aquifer in and near 

3,060

2,980

3,060

3,040

3,580

3,540

3,560

3,080

3,500

3,100

3,480

3,460

3,440

3,420

3,400

3,460

3,460

2,960

2,940

3,060

3,440

3,440

3,700

3,680

3,000

3,660

3,640

3,600

3,520

3,520

3,120

3,140

3,180

3,160

3,320

3,320

3,340

3,340

3,300

3,300

3,360

3,280

3,280

3,380

3,220

3,260

3,260

3,240

3,240

3,240

3,380

3,300

3,200

3,200

3,180

3,620

3,540

3,580

3,340

3,480

3,120

laf16-0739_fig 04

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

380

385

385

380

62

62

82

180

214

137

83

214

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES COUNTY

HOCKLEY

COUNTY

YOAKUM COUNTY TERRY COUNTY

EXPLANATION

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

3,747

2,870

Potentiometric contour

Shows altitude at which water level would have stood in tightly

cased wells. Dashed where approximately located. Contour

interval is 20 feet. Datum is NAVD 88

Groundwater flow path

Edwards-Trinity aquifer downdip extent

Location of groundwater-level measurement well

3,560

Groundwater-level altitude, in feet above

North American Vertical Datum of 1988 (NAVD 88)

0 5 10 15 MILES

0 5 10 15 KILOMETERS

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13 TEXAS

NEW MEXICO

0 5 10 15 MILES

0 5 10 15 KILOMETERS

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13

Terry, and Yoakum Counties, Texas.

Figure 5. Mean recent period (2005–15) groundwater-level-altitude grid for the Ogallala aquifer in and near Gaines, 

3,700

3,400

3,100

3,600

3,200

3,500

3,300

laf16-0739_fig06

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

380

385

385

380

62

62

82

180

214

137

83

214

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES COUNTY

HOCKLEY

COUNTY

YOAKUM

COUNTY

TERRY

COUNTY

EXPLANATION

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

3,814

3,021

Potentiometric contour

Shows altitude at which water level would have stood in tightly

cased wells. Dashed where approximately located. Contour

interval is 100 feet. Datum is NAVD 88

Groundwater flow path (dashed where approximately located)

Edwards-Trinity aquifer downdip extent 

Location of groundwater-level measurement well

3,560

Groundwater-level altitude, in feet above

North American Vertical Datum of 1988 (NAVD 88)

0 5 10 15 MILES

0 5 10 15 KILOMETERS

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13 TEXAS

NEW MEXICO

Gaines, Terry, and Yoakum Counties, Texas.

Figure 7. Mean early development period (1930–60) groundwater-level-altitude grid for the Edwards-Trinity aquifer in and near 

3,700

3,200

3,500

3,100

3,300

3,200

3,600

3,400

laf16-0739_fig07

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

380

385

385

380

62

62

82

180

214

137

83

214

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES COUNTY

HOCKLEY

COUNTY

YOAKUM

COUNTY

TERRY

COUNTY

EXPLANATION

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

3,814

3,021

Potentiometric contour

Shows altitude at which water level would have stood in tightly cased

wells (2005–14). Dashed where approximately located. Contour

interval is 100 feet. Datum is NAVD 88

Groundwater flow path (dashed where approximately located)

Edwards-Trinity aquifer downdip extent

Location of groundwater-level measurement well

3,560

Groundwater-level altitude, in feet above

North American Vertical Datum of 1988 (NAVD 88)

0 5 10 15 MILES

0 5 10 15 KILOMETERS

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13 TEXAS

NEW MEXICO

Gaines, Terry, and Yoakum Counties, Texas.

Figure 8. Mean recent period (2005–15) groundwater-level-altitude grid for the Edwards-Trinity aquifer in and near 

laf16-0739_fig05

10577

11171

10128

11392

380

385

385

380

62

62

82

180

214

137

83

214

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES COUNTY

HOCKLEY

COUNTY

YOAKUM

COUNTY

TERRY

COUNTY

EXPLANATION

Change in groundwater-level altitude, in feet—

 Masked where unknown

≤ -150

> -150 to -125

> -125 to -100

> -100 to -75

> -75 to -50

> -50 to -25

> -25 to 0

> 0 to 25

> 25 to 50

> 50

Well location and identifier (table 10) 11171

Groundwater-level altitude, in feet above North American

 Vertical Datum of 1988 (NAVD 88) (table 10)

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

Edwards-Trinity aquifer downdip extent

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13

0 5 10 15 MILES

0 5 10 15 KILOMETERS

TEXAS

NEW MEXICO

Figure 6. Changes in groundwater-level altitudes in the Ogallala aquifer between the early development (1930–60) and 

recent (2005–15) periods and hydrographs of groundwater-level altitudes measured at selected wells in and near Gaines, 

Terry, and Yoakum Counties, Texas.

laf16-0739_fig05_10128

Measurement date

1955 1965 1975 1985 1995 2005 2015

3,400

3,380

3,360

3,340

3,320

3,300

3,280

3,260

3,240

3,220

3,200

Groundwater-level altitude, in feet above NAVD 88

Well 10128

laf16-0739_fig05_10577

3,600

3,580

3,560

3,540

3,520

3,500

3,480

3,460

3,440

3,420

3,400

Groundwater-level altitude, in feet above NAVD 88

Measurement date

1955 1965 1975 1985 1995 2005 2015

Well 10577

laf16-0739_fig05_11171

Measurement date

1955 1965 1975 1985 1995 2005 2015

3,500

3,480

3,460

3,440

3,420

3,400

3,380

3,360

3,340

3,320

3,300

Groundwater-level altitude, in feet above NAVD 88

Well 11171

Measurement date

1955 1965 1975 1985 1995 2005 2015

3,100

3,080

3,060

3,040

3,020

3,000

2,980

2,960

2,940

2,920

2,900

Groundwater-level altitude, in feet above NAVD 88

Well 11392

laf16-0739_fig08

380

385

385

380

62

62

82

180

214

137

83

214

10071

10223

10621

10741

Brownfield

Denver City

Seagraves

Seminole

Plains

GAINES COUNTY

HOCKLEY

COUNTY

YOAKUM

COUNTY

TERRY

COUNTY

EXPLANATION

Well location and identifier (table 10) 11171

Groundwater-level altitude, in feet above North American

 Vertical Datum of 1988 (NAVD 88) (table 10)

Underground water conservation district boundary

Llano Estacado Underground Water Conservation District

Sandy Land Underground Water Conservation District

South Plains Underground Water Conservation District

Edwards-Trinity aquifer downdip extent

>-50 to -25

> -25 to 0

> 0

≤ -50

Change in groundwater-level altitude, in feet—

 Masked where unknown

102°20' 102°40' 103°00'

33°20'

33°00'

32°40'

Base modified from U.S. Geological Survey 1:250,000-scale to 1:2,000,000-scale digital data,

World Geodetic System of 1984, Universal Transverse Mercator (UTM) Zone 13

0 5 10 15 MILES

0 5 10 15 KILOMETERS

TEXAS

NEW MEXICO

Figure 9. Groundwater-level-altitude changes between the early development (1930–60) and recent (2005–15) periods 

for the Edwards-Trinity aquifer and hydrographs of groundwater-level altitudes measured at selected wells in and near 

Gaines, Terry, and Yoakum Counties, Texas, 1930–2015.

laf16-0739_fig08_10071

3,700

3,680

3,660

3,640

3,620

3,600

3,580

3,560

3,540

3,520

3,500

Groundwater-level altitude, in feet above NAVD 88

Measurement date

1955 1965 1975 1985 1995 2005 12015

Well 10071

laf16-0739_fig08_10223

Measurement date

1955 1965 1975 1985 1995 2005 2015

3,400

3,380

3,360

3,340

3,320

3,300

3,280

3,260

3,240

3,220

3,200

Groundwater-level altitude, in feet above NAVD 88

Well 10223

laf16-0739_fig08_10621

3,700

3,680

3,660

3,640

3,620

3,600

3,580

3,560

3,540

3,520

3,500

Groundwater-level altitude, in feet above NAVD 88

Measurement date

1955 1965 1975 1985 1995 2005 2015

Well 10621

Measurement date

1955 1965 1975 1985 1995 2005 2015

3,400

3,380

3,360

3,340

3,320

3,300

3,280

3,260

3,240

3,220

3,200

Groundwater-level altitude, in feet above NAVD 88

Well 10741

Changes Between Early Development (1930–60) and Recent (2005–15) Groundwater-Level Altitudes and 

Dissolved-Solids and Nitrate Concentrations In and Near Gaines, Terry, and Yoakum Counties, Texas

By

Jonathan V. Thomas, Andrew P. Teeple, Jason D. Payne, and Scott Ikard

2016

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

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, 

Denver, CO 80225, 1–888–ASK–USGS

Digital files available at http://dx.doi.org/10.3133/sim3355

Suggested citation: Thomas, J.V., Teeple, A.P., Payne, J.D., and Ikard, Scott, 2016, Changes 

between early development (1930–60) and recent (2005–15) groundwater-level altitudes and 

dissolved-solids and nitrate concentrations in and near Gaines, Terry, and Yoakum Counties, 

Texas: U.S. Geological Survey Scientific Investigations Map 3355, 2 sheets, pamphlet,

http://dx.doi.org/10.3133/sim3355.

ISSN 2329-1311 (print)

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3355