Water Management Improvement Strategies for the Kansas Lower Republican River Basin

Kansas’ Lower Republican River (LRR) basin has competing needs for its limited water supplies: irrigation, recreation, wildlife areas, municipalities, and minimum streamflow requirements. To improve management options, Kansas entered into a WaterSMART Basin Study with the Bureau of Reclamation and the states of Colorado and Nebraska. The study covers the entire basin and evaluates proposed structural and operational changes in both Nebraska and Kansas. Five alternatives and a no action baseline are examined through hydrologic modeling, economic analysis, and public input to determine their ability to meet demands, be interstate compact compliant, be cost effective, and maintain the ecological function of the river under current and future conditions. Alternatives evaluated within Kansas are the expansion of Lovewell Reservoir by 16,000 AF, 25,000 AF, and 35,000 AF, with the automation and winterization of the Courtland Canal and the off-season storage of water from Lovewell or Courtland Canal in Jamestown Wildlife Area, which is then re-released to the Republican River when other demands increase.

To evaluate these alternatives, the Kansas research team coupled an integrated surface water/groundwater flow model (HydroGeoSphere) and a surface water operations model (OASIS) to characterize the response of the LRR to changing climate conditions and upstream management alternatives. The LRR hydrology is complex with many natural and engineered components that control water flow, and these components are well captured in the coupled model framework for the LRR. For future climate projections, precipitation and temperature conditions are downscaled data from 112 global climatic projections and reflect a central tendency, the 25% (warmer and wetter) and the 75% range (more warmer and drier).

The basin study paves the way for funding a feasibility study and implementation of the best suited alternatives to improve water management in the basin.