July 12, 2001

Contact: Don Whittemore, Kansas Geological Survey, (785) 864-2182.

Geologists project life of Ogallala aquifer

LAWRENCE -- About 40 percent of the area underlain by the Ogallala aquifer should be able to support pumping for the next 100 years or longer, according to water scientists at the Kansas Geological Survey, based at the University of Kansas.

That projection was made this week in Colby at a meeting of a committee brought together by the Kansas Water Office to study the Ogallala aquifer. The projection assumes that water will continue to be used at about the same rate as it was from 1978 to 1998.

The Ogallala aquifer is the primary source of water for the western third of Kansas. Water-level declines in the aquifer have been substantial in the past several decades because of heavy pumping, primarily for irrigation.

In about five percent of the aquifer, water levels are already below 30 feet of saturated thickness. Saturated thickness is the amount of the aquifer that is saturated with water. Thirty feet is considered the minimum amount necessary to support large-scale irrigation.

If use continues at the same rate as 1978 to 1998, about four percent of the aquifer will drop to 30 feet of saturated thickness in the next 25 years. Another six percent would reach the 30-foot level in 25 to 50 years, seven percent more in 50 to 75 years, and five percent more in 75 to 100 years.

Not enough data is available to project depletion in about one-third of the aquifer. Much of the area where data is unavailable is on the edge of the aquifer, where there are relatively few wells available for measurement and the saturated thickness is generally small.

"These results show substantial amounts of water remain in some parts of the aquifer," said Don Whittemore, head of the Survey's geohydrology section. "This also shows us that we need to focus on those areas that are on course to be depleted over the next 50 or so years."

The projection is based on data compiled for the Survey's educational publication Atlas of the High Plains Aquifer. Copies of that book are available for purchase from the Survey by calling (785) 864-3965. Many of the book's maps are on the Survey's Web site at www.kgs.ku.edu/HighPlains/atlas/.