Projected effects of ground-water withdrawals in the Arkansas River Valley, 1980-99, Hamilton and Kearny Counties, southwestern Kansas

A study was made, in cooperation with the Kansas State Board of Agriculture, to determine the effects that additional ground-water development would have on streamflow and water levels on an area along the Arkansas River in Hamilton and Kearny Counties, southwestern Kansas. A computer model was used to simulate the changes in streamflow and water levels from 1980 through 1999. Six pumpage options were tested using variations in pumpage rate and number of wells pumping in the model area. If the full amount appropriated by water rights were pumped rather than actual 1979 conditions of pumpage, annual pumpage would be reduced 24 percent, but net annual river loss would be reduced only 1 percent. A pumpage increase of approximately 19 percent over 1979 pumpage conditions would cause an increase of net annual river loss from 5 to 9 percent. Increased pumpage, in the form of additional wells in the model area, would cause additional ground water to be removed from storage in the aquifer and an increase in net annual river loss.