Changes in the water supply in the Upper Republican Natural Resources District, Southwest Nebraska, from 1952-75

Use of ground water for irrigation has increased rapidly in the Upper Republican Natural Resources District in southwestern Nebraska in recent years. The principal aquifer being developed is composed of saturated and gravel of the Ogallala Formation of Tertiary age. Water-level declines of as much as 16 feet (4.9 meters) have occurred. Base flow of major streams draining the aquifer was reduced by as much as 19 percent between 1967 and 1975. Recoverable ground water in storage was reduced by about 1 percent. New withdrawal of ground water in 1975 was about 250 ,000 acre-feet (308 million cubic meters), compared with estimated recharge from precipitation of 176,000 acre-feet (217 million cubic meters). Water levels and streamflow will continue to decline if ground-water withdrawals continue at or greater than the 1975. (Woodard-USGS)