SIMULATION AND MAPPING OF SOIL-WATER CONDITIONS IN THE GREAT-PLAINS

Soil-water conditions provide valuable insight into the hydrologic sys tem in an area. A soil-water balance quantitatively summarizes soil-wa ter conditions and is based on climatic, soil, and vegetation characte ristics that vary spatially and temporally. Soil-water balances in the Great Plains of the central United States were simulated for 1951-198 0. Results of the simulations were mean annual estimates of infiltrati on, runoff, actual evapotranspiration, potential recharge, and consump tive water and irrigation requirements at 152 climatic data stations. A method was developed using a geographic information system to integr ate and map the simulation results on the basis of spatially variable climatic, soil, and vegetation characteristics. As an example, simulat ed mean annual potential recharge was mapped. Mean annual potential-re charge rates ranged from less than 0.5 inch in much of the north-centr al and southwestern Great Plains to more than 10 inches in parts of ea stern Texas and southwestern Arkansas.