A statistical technique, called kriging, was programmed for a computer to interpolate hydrologic data based on a network of 296 measured values in west-central Kansas and eastern Colorado. The computer program generated estimated values of selected hydrologic data at the center of each 1-mile section in the Western Kansas Groundwater Management District No. 1. This program facilitated contouring of the data that are needed to aid in the management of ground water for irrigation. The kriging technique produced a map that illustrates the percentage change in saturated thickness of the High Plains aquifer from 1950 to average 1980-82 in west-central Kansas. Estimated changes in saturated thickness of the aquifer, as shown on the map, range from about a 50% increase to a 100% decrease. (USGS)