DS-777 Spatial Location of Gages with Total Flow and estimated Base Flow, organized by Seasonal Stress Periods for the Development Simulation Period for the Northern High Plains Groundwater-Flow Model in Parts of Colorado, Kansas, Nebraska, South Dakota, and Wyoming

Baseflow is the portion of streamflow derived from groundwater flow. It is an important component of the groundwater budget, and can be estimated using known total streamflow at given points through time. Daily streamflow data was collected from 91 streamflow gaging stations across the northern High Plains Groundwater Availability Study (NHPGAS) area from the National Water Information System (NWIS) and the Nebraska Department of Natural Resources Stream Gaging Data Bank. The data from each site was processed using the BFI program, version 4.15 (Wahl and Wahl, 2007) to determine the baseflow component of total streamflow at each site. The average daily baseflow was computed for the months of April and October, spanning the development period model (1940-2009). The resulting baseflow values were applied as calibration targets to corresponding stress periods.