Using cumulative potential recharge for selection of GCM projections to force regional groundwater models: A Nebraska Sand Hills example

摘要

Groundwater recharge (GR) controls vegetation, geomorphology, groundwater, wetlands and surface flow, and ultimately, the ecology and economics of semi-arid regions. Therefore, it is critical to assess hydroclimate model scenarios and the uncertainty in future GR to force regional groundwater models. We use basic statistics of downscaled Global Circulation Model (GCM)-projected cumulative potential GR (GR(p)) for selecting representative projections. Cumulative GR(p) is the net recharge (difference between precipitation (P) and evapotranspiration (ET) rates) over the projection period. The approach is illustrated with an example in the Nebraska Sand Hills (NSH), the largest dune region in the Western Hemisphere, where sandy soils are not conducive to overland flow.