R.D. Burnett 1984 Since 1974 water levels in the alluvial aquifer of the North Fork Solomon River Valley in north-central Kansas have decreased due to increases in ground-water pumpage, decreases in availability of surface water for irrigation, and below-average precipitation. A finite-element model was developed in cooperation with the U.S. Bureau of Reclamation to simulate changing conditions between 1970-79. Model results indicate that annual recharge to the aquifer due to precipitation, applcation of water for irrigation, and canal leakage averaged about 22,825 acre-feet and that annual ground-wate discharge to the river averaged about 16,590 acre-feet. Predictive simulations for 1980-2000 were made using management alternatives that involved clay-lining of irrigation ditches, reduction of surface-water availability with and without an increase in ground-water pumping, and continuation of 1979 pumping conditions. The simulations indicated that as much as 5.5 feet of additional average water-level drawdown in wells would occur by 2000 if surface-water supply were reduced 100 percent and ground-water pumpage increased. The simulations also indicated that a decrease in average drawdown of 0.55 foot would occur by 2000 and that base flow to the river would decrease to 12,300 acre-feet per year if 1979 conditions remained constant. (USGS) application/pdf 10.3133/wri844249 en U.S. Geological Survey, Predictive simulation of alternatives for managing the water resources of North Fork Solomon River Valley between Kirwin Dam and Waconda Lake, north-central Kansas reports