HYDROLOGIC IMPACTS OF ANTHROPOGENIC WATER BODIES IN THE UPPER NEOSHO RIVER BASIN: IMPLICATIONS FOR PAST AND FUTURE DROUGHT IN EASTERN KANSAS

Eastern Kansas has been affected by at least three major periods of drought during the past century (1930s, 1950s, 1980s). Subsequent droughts are likely to occur. We may not be able to accurately predict their timing or intensity but we can evaluate the effects of certain landuse changes on future droughts. An example of a temporal landuse change that has not been thoroughly evaluated in terms of its potential effects on future drought is the increase in anthropogenic water bodies. In eastern Kansas the only natural, perennial water bodies prior to settlement were rivers, smaller streams, and associated oxbow lakes. During the past century we have built thousands of water bodies ranging in size from small farm ponds (< 1 hectare) used primarily for stock water, to large reservoirs (>1000 hectares) that are used for flood control, water supplies, and recreation. One of the primary effects of these water bodies is that a much greater percentage of the precipitation received is stored on the landscape and available for evaporation. It also follows that less water is available for runoff to maintain stream flow and reservoir levels during periods of drought. The focus of our study is on temporal changes in pond numbers and their effects on stream flow in the Upper Neosho River. We have used a time series of historical air photos to quantify temporal changes in pond numbers and water area from the 1930s to present. Historical weather maps and stream gaging data are compared with the pond data using GIS analysis to determine the past and future effects of large numbers of ponds on hydrologic drought in eastern Kansas.