U.S. Department of the Interior

U.S. Geological Survey

Water-Level Changes, 1980 to 1997

The water-level changes in the High Plains aquifer result 

from an imbalance between discharge, the largest component of 

which is ground-water withdrawals for irrigation, and recharge, 

which is primarily from precipitation. This imbalance began 

with large-scale development of the aquifer for irrigation. 

Ground-water withdrawals for irrigation in a given year can be 

affected by climatic conditions, particularly precipitation, which 

can cause large variations in the amount of irrigation water 

needed to satisfy the water requirements for crops.

The High Plains aquifer underlies one of the major agricultural regions in the world, including parts of eight States—Colorado,

Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. In the area underlain by the High Plains aquifer 

(called the High Plains region in this report), the total number of acres irrigated with ground water expanded rapidly after 1940: 

1949—2.1 million acres; 1959—6.1 million acres; 1969—9.0 million acres; and 1980—13.7 million acres (Gutentag and others, 1984; 

Thelin and Heimes, 1987). In 1990, about 95 percent of the water withdrawn from the High Plains aquifer (about 15.7 million acre-feet) 

was used for irrigation (Marilee Horn, U.S. Geological Survey, written commun., 1996).

Water-level declines began to occur in the High Plains aquifer soon after extensive ground-water irrigation development began. By 

1980, water levels in the High Plains aquifer in parts of Texas, New Mexico, and southwestern Kansas had declined more than 100 feet 

(Luckey and others, 1981). In response to these declines, the U.S. Geological Survey, in cooperation with numerous Federal, State, and 

local water-resource agencies, began a ground-water monitoring program in 1988 to assess annual water-level change in the aquifer 

using water-level measurements from more than 7,000 wells. The purpose of this report is to present (1) water-level changes in the High 

Plains aquifer from 1980 to 1997 and from 1996 to 1997, (2) the precipitation pattern in the High Plains region during 1996, and (3) estimated saturated thickness of the High Plains aquifer in 1996–97. The water-level measurements used in this report were collected in winter or early spring when irrigation wells were not pumping. Map scale and density of water-level elevation data preclude showing small 

areas in the maps of water-level change and saturated thickness where the value may be more or less than indicated. 

Water levels declined 2.7 feet 

from 1980 to 1997

106 105 104 103 102 101 100 99 98 97 96 

43 

42 

41 

40 

39 

38 

37 

36 

35 

34 

33 

32 

SOUTH DAKOTA

NEBRASKA

KANSAS

TEXAS

NEW MEXICO

COLORADO

WYOMING

N PLATTE RIVER

PLATTE

RIVER

S PLATTE

RIVER

REPUBLICAN

RIVER

ARKANSAS

RIVER NORTHERN

HIGH

PLAINS

CENTRAL

HIGH 

PLAINS

HIGH

PLAINS

AQUIFER

BOUNDARY

SOUTHERN

HIGH 

PLAINS

OKLAHOMA CANADIAN

RIVER

0

0

50

50

100 MILES

100 KILOMETERS

EXPLANATION

Water-level change,

 in feet, 1980 to 1997

Declines

More than 40

20 to 40

10 to 20

5 to 10

No significant change

-5 to 5

Rises

5 to 10

10 to 20

20 to 40

More than 40

Area of little or

 no saturated thickness

Regional subdivision

 boundary

Figure 1. Water-level changes in the High Plains aquifer, 1980 to 1997.

USGS Fact Sheet 124–99

December 1999

The pattern of water-level changes in the High Plains aquifer from 1980 to 1997 (fig. 1) is based on water-level measurements from 5,233 wells (table 1). A large area in the northern 

part of the southern High Plains in New Mexico and Texas with 

greater than 100 feet of water-level declines from predevelopment to 1980 (Luckey and others, 1981) has continued to 

decline, but at slower rates. The average area-weighted rate of 

decline in this area from predevelopment to 1980 was 3.7 feet 

per year; the rate of decline in this area from 1980 to 1997 was 

1.6 feet per year. Areas with substantial water-level declines 

from predevelopment to 1980 in the southern part of the southern High Plains in Texas and in the southeastern part of the 

northern High Plains in Nebraska (Luckey and others, 1981) had 

considerably slower rates of decline, or rising water levels, from 

1980 to 1997.

WATER-LEVEL CHANGES, 1980 TO 1997, AND SATURATED 

THICKNESS, 1996–97, IN THE HIGH PLAINS AQUIFER
Ninety-nine percent of all water-level changes from 1980 

to 1997 are within a rise of 32 feet and a decline of 60 feet. The 

average area-weighted water level in the High Plains aquifer 

declined 2.7 feet from 1980 to 1997 compared to a decline of 

9.9 feet from predevelopment to 1980 (table 2). Assuming 

1950 as the beginning of irrigation development in the High 

Plains region, the rate of water-level decline decreased from 

0.33 foot per year (1950 to 1980) to 0.16 foot per year (1980 

to 1997).

Factors that contributed to the smaller rate of waterlevel decline from 1980 to 1997 as compared to predevelopment to 1980 are: (1) a decrease in ground-water withdrawals 

from the High Plains aquifer for irrigation, and (2) greater than 

normal precipitation from 1980 to 1996. Ground-water withdrawals for irrigation were 18.0 million acre-feet in 1980 

and 15.7 million acre-feet in 1990 (Thelin and Heimes, 1987; 

Marilee Horn, U.S. Geological Survey, written commun., 1996). 

Precipitation from 1981 to 1996 in the High Plains region averaged 21.2 inches per year, 1.4 inches per year more than normal 

(table 3).

Factors that may have caused a decrease in groundwater withdrawals, in addition to increased precipitation, 

include: (1) a decrease in irrigated acreage in areas with 

water-level declines and in areas with large potential rates of 

aquifer depletion; (2) use of more efficient irrigation technology, 

such as low-pressure nozzles and drop tubes on center pivots; 

(3) improved farm-management practices, including irrigation 

scheduling, reuse of irrigation return flow, the conversion to 

alternative crops or crop varieties with smaller consumptive 

irrigation requirements, and methods to retain soil moisture; 

(4) local regulation of ground-water withdrawals for irrigation 

and development of irrigated land; and (5) economic considerations, including declining or stable commodity prices, 

increased production costs (including energy and fertilizer 

costs), and various agricultural programs of the Federal government that encourage the transfer of marginal land out of irrigated 

production.

Table 1. Number of High Plains aquifer wells measured for 1996 

and 1997 and used for the water-level comparison periods—

1980 to 1997 and 1996 to 1997

State

Wells 

measured for:

Wells used for water-level 

comparison periods

1996 1997 1980 

to 1997

1996 

to 1997

Colorado 604 604 502 579

Kansas 1,174 1,298 755 889

Nebraska 3,490 3,617 1,937 3,401

New Mexico 751 547 168 104

Oklahoma 298 268 171 256

South Dakota 114 105 70 100

Texas 2,903 2,581 1,617 2,364

Wyoming 83 63 13 62

High Plains 9,417 9,083 5,233 7,755

106 105 104 103 102 101 100 99 98 97 96 

43 

42 

41 

40 

39 

38 

37 

36 

35 

34 

33 

32 

SOUTH DAKOTA

NEBRASKA

KANSAS

TEXAS

NEW MEXICO

COLORADO

WYOMING

N PLATTE RIVER

PLATTE

RIVER

S PLATTE

RIVER

REPUBLICAN

RIVER

ARKANSAS

RIVER NORTHERN

HIGH

PLAINS

CENTRAL

HIGH 

PLAINS

HIGH

PLAINS

AQUIFER

BOUNDARY

SOUTHERN

HIGH 

PLAINS

OKLAHOMA CANADIAN

RIVER

0

0

50

50

100 MILES

100 KILOMETERS

EXPLANATION

Water-level change,

 in feet, 1996 to 1997

Declines

More than 5

3 to 5

1 to 3

No significant change

-1 to 1

Rises

1 to 3

3 to 5

More than 5

Area of little or

 no saturated thickness

Regional subdivision

 boundary

Figure 2. Generalized water-level changes in the High Plains aquifer, 

1996 to 1997.

Table 2. Characteristics of the High Plains aquifer in 1980 and 

water-level changes in the High Plains aquifer, predevelopment 

to 1980, 1980 to 1997, and 1996 to 1997

[ft, foot; ft/yr, foot per year]

State

Percentage

of total

aquifer

area1

Percentage

of total

volume of

drainable

water in

storage

in 19802

Average area-weighted water-level change

Predevelopment

(1950 to 1980)

1980 to

1997 

1996 to

1997 

Waterlevel

change3

 (ft)

Rate

of

change

(ft/yr)

Waterlevel

change

(ft)

Rate

of

change

(ft/yr)

Waterlevel

change

(ft)

Colorado 8.2 3.7 −4.2 −0.14 −5.9 −0.35 +0.15

Kansas 16.2 9.9 −9.9 −0.33 −8.0 −0.47 +0.23

Nebraska 38.6 65.5 0 0 +2.3 +0.13 +0.58

New Mexico 3.6 1.5 −9.8 −0.33 −4.0 −0.23 −0.65

Oklahoma 4.2 3.4 −11.3 −0.38 −2.7 −0.16 +0.70

South Dakota 2.9 1.8 0 0 +3.1 +0.18 +0.82

Texas 21.5 12.0 −33.7 −1.12 −7.4 −0.43 −0.98

Wyoming 4.8 2.2 0 0 −1.5 −0.09 −0.24

High Plains 100 100 −9.9 −0.33 −2.7 −0.16 +0.08

1Does not include areas of little or no saturated thickness.

2

Modified from Gutentag and others (1984).

3

Luckey and others (1981).
The average area-weighted precipitation during 1996 

in the High Plains region was 22.0 inches, or 2.2 inches greater 

than the 30-year normal (table 3). The precipitation pattern 

ranged from more than 10 inches greater than normal to more 

than 5 inches less than normal (fig. 3).

Saturated Thickness, 1996–97

A saturated-thickness map of the High Plains aquifer 

(fig. 4) was prepared by superimposing a 1996–97 water-table 

map over a map of the elevation of the base of the aquifer and 

contouring the elevation difference. The 1996–97 water-table 

map was based on 10,085 measurements—49 stream elevations 

(March 1997) and 10,036 water-level elevations in wells (1,370 

from 1996 and 8,666 from 1997). A water level was used only if 

the land-surface elevation of the well had been determined; a 1996 

water level was used only if the 1997 water level was not available 

for a given well. Within aquifer areas where there were no 1996 or 

1997 measurements, such as in the northern High Plains in northeastern Wyoming, parts of western Nebraska, and north of the 

South Platte River in northeastern Colorado, the 1980 saturatedthickness contours were used (Weeks and Gutentag, 1981). Around 

the boundary of the aquifer, the contours were approximated.

Saturated thickness in 1996–97 ranged from generally 0 at 

the boundary of the aquifer to more than 1,000 feet in west-central 

Nebraska. The percentage of the area of the High Plains aquifer 

within each saturated thickness interval in 1980 (Gutentag and 

others, 1984) and in 1996–97 is summarized by State in table 4. 

The tabulated results show that the area of the High Plains aquifer 

with less than 100 feet of saturated thickness increased from 

46 percent in 1980 to 49 percent in 1996–97.

Water-Level Changes, 1996 to 1997, 

and Precipitation, 1996

Ninety-nine percent of all water-level changes from 

1996 to 1997 (fig. 2) are within a rise of 11.1 feet and a decline 

of 11.1 feet. The average area-weighted water level in the 

High Plains aquifer rose 0.08 foot from 1996 to 1997 (table 2) 

based on measurements from 7,755 wells (table 1). The 

average area-weighted water-level change in the High Plains 

aquifer from 1996 to 1997 by State ranged from a rise of 

0.82 foot in South Dakota to a decline of 0.98 foot in Texas 

(table 2). 

Water levels rose 0.08 foot 

from 1996 to 1997

106 105 104 103 102 101 100 99 98 97 96 

43 

42 

41 

40 

39 

38 

37 

36 

35 

34 

33 

32 

SOUTH DAKOTA

NEBRASKA

KANSAS

TEXAS

NEW MEXICO

COLORADO

WYOMING

N

PLATTE RIVER

PLATTE

RIVER

S PLATTE

RIVER

REPUBLICAN

R

ARKANSAS

RIVER

NORTHERN HIGH

PLAINS

CENTRAL

HIGH 

PLAINS

HIGH

PLAINS

AQUIFER

BOUNDARY

SOUTHERN

HIGH 

PLAINS

OKLAHOMA CANADIAN

RIVER

0

0

50

50

100 MILES

100 KILOMETERS

EXPLANATION

Less than normal

More than 5

2 to 5

0 to 2

Greater than normal

0 to 2

2 to 5

5 to 10

More than 10

Line of equal annual

 precipitation, 1996—

 Interval 4 inches

1996 departure from

 30-year average annual

 precipitation, in inches

Table 3. Average area-weighted precipitation and comparison 

to 30-year normal precipitation (1961–90) in the High Plains 

region, 1981 to 1996, and 1996

[Data from National Oceanic and Atmospheric Administration, National 

Climatic Data Center, Asheville, North Carolina; data values are in inches 

per year]

State

1981 to 1996 1996

Average 

precipitation

Departure 

from 

30-year 

normal 

Average 

precipitation

Departure 

from 

30-year 

normal

Colorado 17.5 +1.3 19.0 +2.8

Kansas 22.6 +1.3 26.7 +5.4

Nebraska 23.3 +1.5 24.1 +2.3

New Mexico 17.6 +1.3 15.4 −1.0

Oklahoma 21.3 +1.3 25.3 +5.3

South Dakota 20.3 +2.0 22.4 +4.0

Texas 20.1 +1.2 18.6 −0.3

Wyoming 15.6 +1.1 13.6 −0.9

High Plains 21.2 +1.4 22.0 +2.2

Figure 3. Annual precipitation, 1996, and departure from 30-year 

normal precipitation (1961–90) (precipitation data from the National 

Oceanic and Atmospheric Administration, National Climatic Data 

Center, Asheville, North Carolina).
106 105 104 103 102 101 100 99 98 97 96 

43 

42 

41 

40 

39 

38 

37 

36 

35 

34 

33 

32 

SOUTH DAKOTA

NEBRASKA

KANSAS

TEXAS

NEW MEXICO

COLORADO

WYOMING

N PLATTE RIVER

PLATTE

RIVER

S PLATTE

RIVER

REPUBLICAN

RIVER

ARKANSAS

RIVER NORTHERN HIGH

PLAINS

CENTRAL

HIGH 

PLAINS

HIGH

PLAINS

AQUIFER

BOUNDARY

SOUTHERN

HIGH 

PLAINS

CANADIAN

OKLAHOMA

RIVER

0

0

50

50

100 MILES

100 KILOMETERS

EXPLANATION

Saturated thickness,

1996-97, in feet

0 to 50

50 to 100

100 to 200

200 to 400

400 to 600

600 to 800

800 to 1,000

1,000 to 1,200

Area of little or

 no saturated thickness

Regional subdivision

 boundary

Faults—U upthrown side

Printed on recycled paper

References

Gutentag, E.D., Heimes, F.J., Krothe, N.C., Luckey, R.R., and Weeks, J.B., 

1984, Geohydrology of the High Plains aquifer in parts of Colorado, 

Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and 

Wyoming: U.S. Geological Survey Professional Paper 1400–B, 63 p.

Luckey, R.R., Gutentag, E.D., and Weeks, J.B., 1981, Water-level and 

saturated-thickness changes, predevelopment to 1980, in the High Plains 

aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey 

Hydrologic Investigations Atlas HA–652, 2 sheets, scale 1:2,500,000.

National Oceanic and Atmospheric Administration, 1951–96, Climatological 

data set TD–3220: Asheville, N.C., National Climatic Center.

Thelin, G.P., and Heimes, F.J., 1987, Mapping irrigated cropland from Landsat data for determination of water use from the High Plains aquifer in 

parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South 

Dakota, Texas, and Wyoming: U.S. Geological Survey Professional 

Paper 1400–C, 38 p.

Weeks, J.B., and Gutentag, E.D., 1981, Bedrock geology, altitude of base, 

and 1980 saturated thickness of the High Plains aquifer in parts of 

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, 

Texas, and Wyoming: U.S. Geological Survey Hydrologic Investigations Atlas HA–648, 2 sheets, scale 1:2,500,000.

—V.L. McGuire and B.C. Fischer

Table 4. Saturated-thickness distribution in the High Plains aquifer, 1980 and 1996–97

[ft, feet; <, less than]

State

Area of High Plains

aquifer within State1

(square miles)

Year2

Percentage of area within each saturated thickness interval

0 to 100 ft

100 to 200 ft 200 to 400 ft 400 to 600 ft 600 to 800 ft 800 to 1,200 ft 0 to 50 ft 50 to 100 ft

Colorado 14,900 1980 76 18 6 -- -- --

1996–97 58 23 15 4 -- -- --

Kansas 30,500 1980 66 21 12 1 -- --

1996–97 51 19 18 11 1 -- --

Nebraska 63,650 1980 14 21 29 22 10 4

1996–97 9 8 20 28 22 9 4

New Mexico 9,450 1980 85 15 -- -- -- --

1996–97 72 17 11 -- -- -- --

Oklahoma 7,350 1980 58 25 11 6 -- --

1996–97 35 21 28 12 4 -- --

South Dakota 4,750 1980 44 13 25 18 -- --

1996–97 26 12 15 32 15 -- --

Texas 35,450 1980 61 25 14 -- -- --

1996–97 33 32 <23 12 <1 -- --

Wyoming 8,000 1980 46 26 18 4 4 2

1996–97 41 7 28 16 <5 <4 <1

High Plains 174,050 1980 46 22 18 9 4 1

1996–97 32 17 20 17 9 4 1

1

Luckey and others (1981), includes areas of little or no saturated thickness.

2

All 1980 values are from Gutentag and others (1984).

Figure 4. Saturated thickness of the High Plains aquifer, 1996–97 

(modified from Weeks and Gutentag, 1981).

For more information, please contact:

District Chief

U.S. Geological Survey

Room 406, Federal Building

100 Centennial Mall North

Lincoln, Nebraska 68508

(402) 437–5082

On the web: http://www-ne.cr.usgs.gov