J.S. Havens 1983 During 1978, the U.S. Geological Survey began a 5-year study of the High Plains regional aquifer system to provide hydrologic information for evaluation of the effects of long-term development of the aquifer and to develop computer models for prediction of aquifer response to alternative changes in ground-water management (Weeks, 1978). This report is one of a series presenting hydrologic information of the High Plains aquifer in Oklahoma. The predevelopment to 1980 water-level changes in the High Plains regional aquifer in Oklahoma are shown for Harper, Ellis, Woodward, Dewey, and Roger Mills Counties, on the east, and for the Oklahoma Panhandle, consist- ing of Cimarron, Texas, and Beaver Counties, on the west. About 1,470 water-level measurements in the Panhandle were used in compiling the predevelopment water-table map (Havens, 1982c). In the remaining area to the east about 150 water-level measurements from the 1950's to the 1970's are representative of predevelopment water levels. For the 1980 water-table map, about 330 measurements were made in the Panhandle and about 350 measurements in the eastern area by the Oklahoma Water Resources Board (Havens, 1982b). application/pdf 10.3133/wri834073 en U.S. Geological Survey, Water-level changes in the high plains regional aquifer, northwestern Oklahoma, predevelopment to 1980 reports