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 overlying the High Plains aquifer, the 

total number of acres irrigated with ground 

water increased rapidly after 1940 and was 

2.1 million acres in 1949, 13.7 million acres 

in 1980, and 13.9 million acres in 1997—

(Heimes and Luckey, 1982; Thelin and 

Heimes, 1987; U.S. Department of Agriculture, 1999). Water-level declines started to 

occur in the High Plains aquifer soon after 

the beginning of extensive ground-water irrigation. The water-level declines in the High 

Plains aquifer occur because of an imbalance 

between discharge, the largest component of 

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

precipitation. By 1980, water levels in the 

High Plains aquifer in parts of Texas, Oklahoma, and southwestern Kansas had declined 

more than 100 feet (Luckey and others, 

1981).Water-level declines may result in 

additional cost for ground-water withdrawals 

because of increased pumping lift and 

decreased well yields. Water-level declines 

also can affect ground-water availability, 

streamflow, and health of riparian areas. In 

response to the water-level declines, the U.S. 

Geological Survey, in cooperation with 

numerous Federal, State, and local waterresource agencies, began a monitoring program in 1988 to assess annual water-level 

change in the aquifer using measurements 

from more than 7,000 wells. The purpose of 

this report is to present water-level changes 

in the High Plains aquifer from the time prior 

to significant ground-water irrigation development (termed predevelopment in this 

report) to 2001, 1999 to 2000, and 2000 to 

2001. The water-level measurements used in 

this report were collected in winter or early 

spring when irrigation wells generally were 

not pumping.

Water-Level Changes in the High Plains Aquifer, 

Predevelopment to 2001, 1999 to 2000, and 2000 to 2001

—By V.L. McGuire

Figure 1. Water-level changes in the High Plains aquifer, predevelopment 

to 2001 (Modified from Luckey and others, 1981; McGuire and Fischer, 

1999).

U

U

U

U U

U

U

Faults U, upthrown side U

 Declines

 More than 150

 100 to 150 

 50 to 100 

 

 No Significant Change

 –10 to 10

 Rises

 10 to 25

 25 to 50

 More than 50

 Area of little or

 no saturated thickness

 WATER- LEVEL CHANGE, IN FEET

EXPLANATION

NEW MEXICO

COLORADO

TEXAS

KANSAS

NEBRASKA

WYOMING SOUTH DAKOTA

OKLAHOMA

HIGH

PLAINS

AQUIFER

BOUNDARY

 25 to 50

 10 to 25

0 50 

0 50 100 MILES

100 KILOMETERS

Base from U.S. Geological Survey digital data, 1:2,000,000

Albers Equal-Area projection

Standard parallels 29°30' N and 45°30' N, central meridian 101°N
B

0 50 100 MILES

0 50 100 KILOMETERS

A

0 50 100 MILES

0 50 100 KILOMETERS

WATER-LEVEL CHANGES, 1999 TO 2000 

AND 2000 TO 2001

Ninety-nine percent of all water-level changes from 

1999 to 2000 were from a rise of 7.4 feet to a decline of 

8.3 feet. The average area-weighted water-level change in 

the High Plains aquifer was a decline of 0.23 foot from 1999 

to 2000 based on measurements from 7,403 wells (table 1). 

The largest areas of water-level decline are in northeast 

Nebraska, northeast Colorado, southwest Kansas, the Oklahoma Panhandle, and most of the aquifer area in Texas 

(fig. 2A).

Ninety-nine percent of all water-level changes from 

2000 to 2001 were from a rise of 7.4 feet to a decline of 

8.7 feet. The average area-weighted water-level change in 

the High Plains aquifer was a decline of 0.62 foot from 2000 

to 2001 based on measurements from 7,650 wells (table 1). 

Water-level declines occurred over most of the aquifer area 

except in part of Texas, primarily north of the Canadian 

River where water-level rises occurred (fig. 2B). 

The cumulative loss of water in storage in the aquifer 

from 1987 to 2002 is about 56 million acre-feet (fig. 3), 

which represents about 29 percent of the cumulative loss 

since predevelopment.

 The water-level change maps in this report were 

prepared using two methods. The map of water-level 

changes, predevelopment to 2001 (fig. 1) was contoured 

manually using the predevelopment to 2001 water-levelchange values for each well. The water-level change maps, 

1999 to 2000 and 2000 to 2001 (fig. 2A and fig. 2B) were 

generated using Thiessen-polygons (Thiessen, 1911). A 

Thiessen polygon was created for each well; the size of each 

polygon depends on the proximity of neighboring wells. 

WATER-LEVEL CHANGES, 

PREDEVELOPMENT TO 2001

The map of water-level changes in the High Plains aquifer from predevelopment to 2001 (fig. 1) is based on water 

levels from 4,071 wells (table 1). The area-weighted average 

water-level change was a decline of 11.1 feet, and the water 

removed from the aquifer through 2001 is estimated to be 

about 200 million acre-feet. The greatest water-level changes 

occurred in southwestern Kansas and in the southwestern part 

of the Texas Panhandle (fig. 1). In most of the southwestern 

part of the Texas Panhandle, more than 50 percent of the 

predevelopment saturated thickness has been dewatered 

(McGuire and Fischer, 1999). 

Figure 2. Generalized water-level changes in the High Plains aquifer, (A) 1999 to 2000 and (B) 2000 to 2001.
–6

–4

–2

2

Storage accretion

Storage depletion

19871989199119931995199719992001

CUMULATIVE CHANGE IN GROUND-WATER STORAGE

SINCE 1987, IN MILLIONS OF ACRE-FEET

Table 1. Number of wells measured and used in this report for predevelopment, 1999, 2000, and 2001 

and number of wells used for the water-level comparison periods—predevelopment to 2001, 

1999 to 2000, and 2000 to 2001.

State

Wells measured and used in this report Wells used in water-level

comparison periods

Predevelopment 1999 2000 2001 Predevelopment 

to 2001

1999 to 

2000 

2000 to 

2001

Colorado 614 570 548 557 404 531 527

Kansas 4,169 1,266 1,214 1,366 634 1,163 1,153

Nebraska 6,681 3,604 3,699 3,849 1,710 3,275 3,537

New Mexico 3,197 24 167 525a 319a 18 89

Oklahoma 1,270 242 214 242 163 175 167

South Dakota 72 112 160 113 72 93 94

Texas 4,823 2,515 2,541 2,525b 750b 2,098 2,028b

Wyoming 26 53 59 60 19 50 55

High Plains (Total) 20,852 8,386 8,602 9,237 4,071 7,403 7,650

a

Includes well measured in New Mexico, 1997 to 2000, because many wells in New Mexico are measured on a rotating 5-year 

schedule. b

Includes wells in Howard and Martin County, Texas, with estimated 2001 water levels based on an average of 2000 and 2002 water 

levels, because few wells were measured in these counties in 2001.

Figure 3. Cumulative changes in ground-water storage in the High 

Plains aquifer since 1987 (modified from U.S. Geological Survey, 

2002).

A center-pivot irrigation system with drop tubes, in Dundy 

County, Nebraska (Photograph courtesy of M.K. Landon, 

U.S. Geological Survey.)
Fact Sheet FS–078–03

REFERENCES

Heimes, F.J., and Luckey, R.R., 1982, Method for estimating irrigation requirements from ground water in 

the High Plains in parts of Colorado, Kansas, 

Nebraska, New Mexico, Oklahoma, South Dakota, 

Texas, and Wyoming: U.S. Geological Survey 

Water-Resources Investigations Report 82–40, 64 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.

McGuire, V.L. and Fischer, B.C, 1999, Water-level 

changes, 1980 to 1997, and saturated thickness, 

1996–97, in the High Plains Aquifer: U.S. 

Geological Survey Fact Sheet, FS–124–99, 4 p. 

Thiessen, A.H., 1911, Precipitation averages for large 

areas: Monthly Weather Review, v. 39, p. 1082–

1084.

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.

U.S. Department of Agriculture, 1999, 1997 Census of 

Agriculture Geographic area series: National Agricultural Statistics Service CD–ROM AC97–CD–

VOL1–1B.

U.S. Geological Survey, 2002, Concepts for national 

assessment of water availability and use: U.S. 

Geological Survey Circular 1223, 34 p.

September 2003

Windmill-powered well and livestock-watering tank, Platte 

County, Wyoming (Photograph courtesy of J.P. Mason, 

U.S. Geological Survey.)

Rangeland in Kit Carson County, Colorado (Photograph 

courtesy of R.R. Luckey, U.S. Geological Survey.)

For additional information contact:

U.S. Geological Survey,

Federal Bldg., Room 406,

100 Centennial Mall North

Lincoln, NE 68508

(402) 437–5082

USGS Nebraska District home page:

http://ne.water.usgs.gov

U.S. Department of the Interior

U.S. Geological Survey

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