News Release, Kansas Geological Survey, Nov. 15, 1994
That's according to an annual report on water-level changes in Kansas irrigation wells published recently by the Kansas Geological Survey, based at the University of Kansas.
The report shows water levels as measured in more than 1500 irrigation wells, most of them in the western two-thirds of the state. The measurement program is co-sponsored by the Kansas Geological Survey, the U.S. Geological Survey, and the Division of Water Resources of the State Board of Agriculture. The wells were measured in January, 1994, to allow water levels to stabilize after summer rains and pumping for irrigation.
Water levels rose in about 60 percent of the measured wells, compared to measurements made in January, 1993. Water researchers attributed those increases to heavy rains that began in June, 1993. Those rains reduced the need for irrigation so that groundwater levels were not lowered as quickly as they are during times of heavy irrigation. Also, in some wells, part of the precipitation made its way back underground into shallow aquifers and caused water levels to rise.
In spite of water level increases in many wells, most of the wells in the western third of the state still show a long-term decline.
In much of southwestern Kansas, water levels decreased from a few inches to five feet in 1994 as compared to 1993. In portions of Grant and Stanton counties, some declines exceeded five feet.
"Most of southwestern Kansas relies on the Ogallala aquifer for irrigation water," said Robert Buddemeier, chief of the Survey's geohydrology section and one of the authors of the report. "Because the Ogallala is fairly deep underground, very little precipitation makes it way back down to recharge the aquifer."
Southwestern Kansas shows some of the most severe long-term drawdowns. In parts of Grant and Morton counties, wells show an average decline of 150 feet since large-scale irrigation began in the 1950s. In places, more than half of the water originally in place in the Ogallala has been pumped away.
Fewer declines were measured in west-central Kansas wells in 1994, and water levels were stable or increased from one to five feet in many areas, as they did in parts of Scott, Wichita, and Greeley counties. Long-term declines of more than 50 feet, however, are common in those same counties.
Water levels increased across much of northwestern Kansas in 1994, though there were decreases in wells in northeastern Thomas County. Again, because most irrigation is from the Ogallala aquifer and recharge is slight, those increases probably resulted from lessened irrigation in 1993. Long-term decreases still average more than 50 feet in parts of Sheridan and Sherman counties.
Increases in 1994 were most dramatic in south-central Kansas, where much shallower aquifers and sandy soils make it easier for precipitation to move back underground and recharge the aquifer. In much of Stafford County and parts of Reno, Barton, and Pawnee counties, wells showed an average increase of four to six feet in 1994 compared to 1993. Eighty-five percent of the measured wells showed increases; the average well showed a water-level rise of nearly two-and-a-half feet.
Over the long-term, water levels in much of south-central Kansas are stable or show a decline of less than ten feet, though water levels have declined more than 25 feet in a portion of Edwards County.
"For much of the state, water levels increased during 1993, or they declined more slowly, because of all the rain," said Buddemeier. "But I think it's safe to say that the long-term trend is still declining water levels, particularly in the western third of the state. This report is not a sign that we no longer need to worry about water in western Kansas."
In addition to a general interpretation of water-level data for the state, the report lists each well that was measured, the depth to water in 1994, changes in water level over time, and other information.
Copies of the report, January 1994 Kansas Water Levels and Data Related to Water-level Changes are available from the Kansas Geological Survey, West Campus, University of Kansas, Lawrence, KS 66047. The cost is $10 per copy plus $2.00 shipping and handling. Kansas residents should add 5.9% sales tax.