Water supply and demand in Sedgwick County, Kansas

Water supplies in Sedgwick County, Kansas, are derived from surface--and groundwater resources. During 1985, public supply, irrigation, and self-supplied industry required 38% of the 56 ,500 acre-ft of appropriated surface water and 57% of the 187 ,800 acre-ft of appropriated groundwater. If the historic (1920-80) annual population growth rate (2.8%) continues, the 126,100 acre ft of water appropriated for public-water supplies should meet demand until 2015. The quantity of potentially available water supplies was estimated by summing those resources having less than 1.00 mg/L dissolved solids. Surface water resources that meet this criterion are the Little Arkansas and Ninnescah Rivers and Cheney Reservoir. Subtracting legislated minimum streamflows for the rivers from their mean annual streamflow volumes leaves 532,000 acre-ft, which combined with the annual sustained yield of Cheney Reservoir (40,000 acre-ft) provides an estimated 572,000 acre-ft of surface water annually. Groundwater that meets the criterion was estimated by summing the annual precipitation recharge available to unconsolidated deposits in the county (78,400 acre-ft) and in the Harvey County part of the Wichita well field (13,000 acre-ft). Although more groundwater is available, withdrawals exceeding annual precipitation recharge would cause water level declines. Because less than 4% of the potentially available surface water was used for supplies in 1985 and because about 120% of the groundwater recharge was used, surface water resources have a greater potential for meeting future water use demands. (USGS)