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 parts of the area that overlie the High Plains 

aquifer, farmers began extensive use 

of ground water for irrigation starting 

in the 1930’s and 1940’s. Estimated 

irrigated acreage in the area that 

overlies the High Plains aquifer 

increased rapidly from 1940 to 1980, 

but did not change greatly from 1980 

to 2002: 1949–2.1 million acres,

1980–13.7 million acres, 1997–

13.9 million acres, 2002–12.7 million acres. However, the proportion 

of irrigated acreage in each state 

relative to total irrigated acres did 

change substantially over time in 

some states: 1980–21 percent of 

irrigated acres were in Kansas, and 

38 percent of irrigated acres were 

in Nebraska; 2002–15 percent of 

irrigated acres were in Kansas, and 

45 percent of irrigated acres were 

in Nebraska (Heimes and Luckey, 

1982; Thelin and Heimes, 1987; 

U.S. Department of Agriculture, 

1999, 2004). Annual ground-water 

withdrawals from the High Plains 

aquifer for irrigation, which is 

compiled by the U.S. Geological 

Survey and agencies in each State 

about every 5 years, increased from 

4 to 19 million acre-feet from 1949 

to 1974; ground-water withdrawals 

for irrigation decreased from 1974 

to 1995 and increased from 1995 to 

2000 (Heimes and Luckey, 1982; 

U.S. Geological Survey, 2004; U.S. 

Geological Survey’s National WaterData Storage and Retrieval System 

database). Ground-water withdrawals 

for irrigation in 1980, 1985, 1990, 

and 1995 were from 4 to 18 percent 

less than withdrawals for irrigation in 

1974. Ground-water withdrawals for 

irrigation in 2000 were 12 percent 

greater than withdrawals in 1995 and 

2 percent greater than withdrawals in 

1974. Ground-water withdrawals for 

irrigation during 2000 by county in 

the area that overlies the High Plains 

aquifer ranged from zero to 

U.S. Department of the Interior

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0 50 100 MILES

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—By V.L. McGuire

Water-Level Changes in the High Plains Aquifer, 

Predevelopment to 2003 and 2002 to 2003

Fact Sheet 2004–3097

September 2004

Figure 1. Ground-water withdrawals for irrigation by county during 2000 (U.S. Geological Survey, 2004).
0.5 million acre-feet (fig. 1); more than 96 percent of the total 

withdrawals from the aquifer were for irrigation (U.S. Geological 

Survey, 2004; Joan Kenny, U.S. Geological Survey, written commun., March 2004). 

Water-level declines started to occur in the High Plains aquifer 

soon after the beginning of extensive ground-water irrigation. 

The water-level changes in the High Plains aquifer result from 

an imbalance between discharge and recharge. Discharge is 

primarily from ground-water withdrawals for irrigation, but also 

includes evapotranspiration, where the water table is near land 

surface, and seepage to streams and springs where the water table 

intersects the land surface. Recharge is primarily from precipitation; other sources of recharge are irrigation return flow and 

seepage from streams, canals, and reservoirs. 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 increased 

costs for ground-water withdrawals because of increased pumping lift and decreased well yields. Water-level declines also can 

affect ground-water availability, surface-water flow, and nearstream habitat (riparian) areas. 

In response to the water-level declines in the High Plains aquifer, the U.S. Geological Survey, in cooperation with numerous 

Federal, State, and local water-resource agencies, began monitoring more than 7,000 wells in 1988 to assess the annual waterlevel change in the aquifer; there were 9,202 wells measured for 

2003 (table 1). The purpose of this report is to present water-level 

changes in the High Plains aquifer from the time prior to substantial ground-water irrigation development (about 1950, which 

is termed “predevelopment” in this report) to 2003 and from 

2002 to 2003. The water-level measurements used in this report 

generally were collected in winter or early spring, when irrigation 

wells typically were not pumping and water levels generally had 

Table 1. Number of wells used in this report for 2003 water levels 

and number of wells used for the water-level comparison periods, 

predevelopment to 2003 and 2002 to 2003.

Table 2. Area-weighted average water-level changes in the High 

Plains aquifer, not including the areas of little or no saturated 

thickness, predevelopment to 2003 and 2002 to 2003.

The water-level-change maps and related area-weighted average water-level change values in this report were prepared using 

two methods. The map of water-level changes, predevelopment to 

2003 (fig. 2), shows areas of water-level change ranges, which 

were determined manually based on predevelopment and 2003 

water-level data from available wells and areas of water-level 

changes from previous reports (Lowry and others, 1967; Luckey 

and others, 1981; Nebraska Conservation and Survey Division, 

2004). The map of generalized water-level changes, 2002 to 2003 

(fig. 3), shows computer-generated Thiessen polygons 

(Thiessen, 1911), colored by the water-level-change range. 

Thiessen polygons apportion the water-level change in each well 

to an area around the well; the size of each polygon depends on 

the proximity of neighboring wells. 

The predevelopment to 2003 area-weighted average waterlevel change (table 2) was computed by summing the quantity 

equal to the area within each polygon of water-level change 

2003

Colorado 468 333 455

Kansas 1,424 606 1,313

Nebraska 3,776 1,579 3,506

New Mexico 154 204 * 107

Oklahoma 290 175 263

South Dakota 115 70 111

Texas 2,922 807 2,404

Wyoming 53 18 49

High Plains (Total) 9,202 3,792 8,208

Wells used in waterlevel comparison

periods

State

* Includes 1999 to 2002 water levels, instead of 2003 water levels, for 

166 wells because many wells in New Mexico are measured on a 

5-year schedule.

Predevelopment to

2003

2002 to

2003 

Colorado

Kansas

Nebraska

New Mexico

Oklahoma

South Dakota

Texas

Wyoming

Predevelopment 

to 2003

(feet)

2002 to

2003

(feet) 

–9.9 –1.0

–18.9 –1.7

–0.3 –1.3

–14.4 –0.6

–13.7 –0.8

0.2 –0.8

–34.9 –1.2

–0.2 –0.3

High Plains (Total) –12.6 –1.2

Area-weighted 

average waterlevel change

State

multiplied by the value of the mid-point of the polygon range and 

by dividing the result by the total area. The 2002 to 2003 areaweighted average water-level change was computed by summing 

the quantity equal to the area of each Thiessen polygon multiplied by the actual water-level change value associated with the 

Thiessen polygon and by dividing the result by the total area.

WATER-LEVEL CHANGES, PREDEVELOPMENT 

TO 2003

The map of water-level changes in the High Plains aquifer from 

predevelopment to 2003 (fig. 2) is based on water levels from 

3,792 wells (table 1). The water-level changes from predevelopment to 2003 ranged between a rise of 86 feet and a decline of 

223 feet. The area-weighted average water-level change across 

the High Plains, not including the areas with little or no saturated 

thickness, was a decline of 12.6 feet (table 2). Approximately 

24 percent of the aquifer area, not including the areas with little 

or no saturated thickness, had more than 10 feet of water-level 

decline from predevelopment to 2003; 17 percent had more than 

recovered from the stress of pumping during the previous irrigation season; an exception was that in 2003, most wells in South 

Dakota were measured in late spring or early summer. 
25 feet of water-level decline, and 9 percent had more that 50 feet 

of water-level decline. The largest areas with greater than 50 feet 

of water-level decline occurred in southwest Kansas, east-central 

New Mexico, the central part of the Oklahoma Panhandle, and the 

western part of the Texas Panhandle.

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Figure 2. Water-level changes in the High Plains aquifer, predevelopment to 2003 (Modified from Lowry 

and others, 1967; Luckey and others, 1981; Nebraska Conservation and Survey Division, 2004).

WATER-LEVEL CHANGES, 2002 TO 2003

Water-level changes in the 8,208 wells used for the 2002 to 

2003 comparison period (table 1) ranged between a rise of 9 feet 

and a decline of 14 feet; water-level declines of 3 feet or greater 

occurred in 19 percent of the wells measured (fig. 3). The areaweighted average water-level change in the High Plains aquifer 
from 2002 to 2003, not including the areas of little or no saturated 

thickness, ranged by State from a decline of 1.7 feet in Kansas to 

a decline of 0.3 foot in Wyoming (table 2). The area-weighted 

average water-level change in the High Plains aquifer from 2002 

to 2003 for the aquifer area, not including the areas of little or no 

saturated thickness, was a decline of 1.2 feet (table 2).

Figure 3. Generalized water-level changes in the High Plains aquifer, 2002 to 2003.

CHANGE IN WATER IN STORAGE, PREDEVELOPMENT TO 2003

Because the High Plains aquifer is generally unconfined, the 

change in water in storage in the High Plains aquifer can be estimated using the water-level change maps (figs. 2 and 3) and the 

average specific yield of the aquifer (Gutentag and others, 1984). 

Specific yield is an estimate of the volume of water that a volume 

of the aquifer will yield by gravity drainage (Lohman, 1979).

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NEW MEXICO

COLORADO

TEXAS

KANSAS

NEBRASKA

WYOMING SOUTH DAKOTA

OKLAHOMA

HIGH

PLAINS

AQUIFER

BOUNDARY

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Predevelopment to 2003

(million acrefeet)

2002 to 2003

(million

acre-feet)

Colorado -13.9 -1.1

Kansas -55.6 -4.1

Nebraska -11.4 -8.1

New Mexico -9.0 -0.3

Oklahoma -11.4 -0.5

South Dakota -0.4 -0.4

Texas -133.0 -4.2

Wyoming -0.5 -0.2

High Plains (Total) -235.2 -18.9

State

Change in water in storage

Table 3. Change in water in storage in the High 

Plains aquifer, predevelopment to 2003 and 2002 

to 2003.

Figure 4. Cumulative change and total ground-water in storage in the High Plains 

aquifer for selected years, predevelopment through 2003 (Modified from McGuire 

and others, 2003; McGuire, 2004).

Cattle grazing in Cimarron County, Oklahoma 

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

Year for which storage

change was computed

1950 1960 1970 1980 1990 2000

–250

–225

–200

–175

–150

–125

–100

–75

–50

–25

2,950

2,975

3,000

3,025

3,050

3,075

3,100

3,125

3,150

3,175

0

CUMULATIVE CHANGE IN GROUND-WATER STORAGE,

SINCE PREDEVELOPMENT (ABOUT 1950), 

IN MILLION ACRE-FEET

TOTAL GROUND WATER IN STORAGE, 

IN MILLION ACRE-FEET

This method for calculating the change in water in 

storage will overestimate the change in storage in 

local areas if the aquifer was under confined conditions at the start of the time period and unconfined 

conditions later.

Total water in storage in 2003 was about 2,940 

million acre-feet, which was a decline of about 235 

million acre-feet since predevelopment (fig. 4); total 

water in storage in 2003 was estimated from total 

water in storage in 2000, which was based on the 

saturated thickness of the aquifer in 2000 (McGuire 

and others, 2003), and the sum of annual changes 

in water in storage from 2000 to 2003, which was 

based on average area-weighted water-level changes 

calculated from Theissen polygons (McGuire, 2003, 

2004; table 3). Total water in storage in predevelopment was inferred from total water in storage in 2000 

and water-level changes, predevelopment to 2000 

(McGuire and others, 2003). There were changes in 

storage prior to “predevelopment,” as defined in this 

report, but this change in storage was not calculated

here. Water in storage declined about 150 million 

acre-feet from predevelopment to 1980 based on 

predevelopment and 1980 water levels (Luckey and 

others, 1981; McGuire, 2004); the annual change in 

storage from predevelopment to 1980 and from 1981 

to 1987 were not calculated for this report. For this 

report, total ground water in storage from 1988 to 

2000 (fig. 4) was calculated by subtracting annual 

changes in water in storage, 1988 to 2000, from total 

water in storage in 2000 (Dugan and Cox, 1994; 

Dugan and others, 1990, 1994; Dugan and Schild, 

1992; Dugan and Sharpe, 1996; Kastner and others, 

1989; McGrath and Dugan, 1993; McGuire, 2001, 

2003; McGuire and Fischer, 1999, 2000; McGuire 

and others, 1999, 2003; McGuire and Sharpe, 1997). 

The sum of annual changes in water in storage from 

1988 to 2000 was a decline of about 47 million acrefeet, based on average area-weighted water-level 

changes calculated from Thiessen polygons. 
REFERENCES

Dugan, J.T., and Cox, D.A., 1994, Water-level changes in the High 

Plains aquifer—Predevelopment to 1993: U.S. Geological Survey 

Water-Resources Investigations Report 94–4157, 60 p. 

Dugan, J.T., McGrath, T.S., and Zelt, R.B., 1994, Water-level changes in 

the High Plains aquifer—Predevelopment to 1992: U.S. Geological 

Survey Water-Resources Investigations Report 94–4027, 56 p. 

Dugan, J.T., and Schild, D.E., 1992, Water-level changes in the High 

Plains aquifer—Predevelopment to 1990: U.S. Geological Survey 

Water-Resources Investigations Report 91–4165, 55 p. 

Dugan, J.T., Schild, D.E., and Kastner, W.M., 1990, Water-level changes 

in the High Plains aquifer underlying parts of South Dakota, Wyoming, Nebraska, Colorado, Kansas, New Mexico, Oklahoma, and 

Texas—Predevelopment through nonirrigation season 1988-89: U.S. 

Geological Survey Water-Resources Investigations Report 90–4153, 

29 p.

Dugan, J.T., and Sharpe, J.B., 1996, Water-level changes in the High 

Plains aquifer—Predevelopment to 1994: U.S. Geological Survey 

Water-Resources Investigations Report 95–4208, 1 sheet. 

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.

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.

Kastner, W.M., Schild, D.E., and Spahr, D.S., 1989, Water-level changes 

in the High Plains Aquifer underlying parts of South Dakota, 

Wyoming, Nebraska, Colorado, Kansas, New Mexico, Oklahoma, and 

Texas—predevelopment through nonirrigation season 1987-88: U.S. 

Geological Survey Water-Resources Investigations Report 89–4073, 

61 p.

Lohman, S.W., 1979, Ground-water hydraulics: U.S. Geological Survey 

Professional Paper 708, 70 p.

Lowry, M.E., Crist, M.A., and Tilstra, J.R.,1967, Geology and groundwater resources of Laramie County, Wyoming; with a section on 

chemical quality of ground water and of surface water: U.S. 

Geological Survey Water-Supply Paper 1834, 71 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.

McGrath, T., and Dugan, J.T., 1993, Water-level changes in the High 

Plains Aquifer—predevelopment to 1991: U.S. Geological Survey 

Water-Resources Investigations Report 93–4088, 53 p.

McGuire, V.L., 2001, Water-level changes in the High Plains Aquifer, 

1980–1999: U.S. Geological Survey Fact Sheet FS-0029–01, 2 p.

McGuire, V.L., 2003, Water-level changes in the High Plains aquifer, 

predevelopment to 2001, 1999 to 2000, and 2000 to 2001: U.S. 

Geological Survey Fact Sheet FS-078-03, 4 p.

McGuire, V.L., 2004, Water-level changes in the High Plains aquifer, 

predevelopment to 2002, 1980 to 2002, and 2001 to 2002: U.S. 

Geological Survey Fact Sheet FS-2004–3026, 6 p.

McGuire, V.L., and Fischer, B.C., 2000, Water-level changes in the High 

Plains, 1980 to 1998: U.S. Geological Survey, accessed 

August 26, 2004 at URL http://www-ne.cr.usgs.gov/highplains/hp98_

web_report/hp98fs.htm.

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.

McGuire, V.L., Johnson, M.R., Schieffer, R.L., Stanton, J.S., Sebree, 

S.K., and Verstraeten, I.M., 2003, Water in storage and approaches to 

ground-water management, High Plains aquifer, 2000: U.S. 

Geological Survey Circular 1243, 51 p.

McGuire, V.L., and Sharpe, J.B., 1997, Water-level changes in the High 

Plains Aquifer, 1980 to 1995: U.S. Geological Survey Fact Sheet 

FS-0068–97, 4 p.

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

changes in the High Plains aquifer—1980 to 1996: U.S. Geological 

Survey, accessed August 26, 2004, at URL http://ne.water.usgs.gov/

html/highplains/hp96_web_report/hp96_factsheet.htm.

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of Nebraska–Lincoln data, accessed July 11, 2004 at 

URL http://csd.unl.edu/csd-esic/gisdata/pred03z14.e00.

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Weather Review, v. 39, p. 1082–1084.

Thelin, G.P., and Heimes, F.J., 1987, Mapping irrigated cropland from 

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

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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