MANAGING THE WATER RESOURCES OF THE LOWER REPUBLICAN RIVER BASIN

Understanding groundwater-surface water interactions is essential to the effective management of the water resources of the Republican River Basin (RRB), located in Colorado, Nebraska and Kansas. This presentation will describe some of the past and current research activities that quantify and manage water resources of the RRB, focusing on the lower portion of the basin in Kansas. Surface water and groundwater of the RRB are heavily utilized by all three states for agricultural, recreational, industrial and domestic use. The Republican River basin has historically experienced severe droughts and floods. In 1942, the three states entered into the Republican River Compact which apportioned all the waters of the RRB between the three states. The compact, in turn, paved the way for significant federal investments in the basin for flood control and water supply including a series of dams, reservoirs and irrigation projects along the river valley. Imbalances between water supplies and demands continue in the basin. New research is being undertaken by the three states and the Bureau of Reclamation to explore system improvements. As part of this work, the state of Kansas will link the surface water operations model OASIS with the integrated hydrologic model HydroGeoSphere, enabling the impacts of current and future water management strategies on the surface and groundwater resources of the Lower RRB to be evaluated. Potential impacts of climate change to the RRB system will also be evaluated. This work emphasizes the need to include groundwater, surface water and their interactions in water management strategies and planning.