Effect of Watershed Delineation and Climate Datasets Density on Runoff Predictions for the Upper Mississippi River Basin Using SWAT within HAWQS

The quality of input data and the process watershed delineation can affect accuracy runoff predictions in modeling. Upper Mississippi River Basin was selected to evaluate effects subbasin and/or hydrologic response unit (HRU) delineations density climate dataset on simulated streamflow water balance components using Hydrologic Water Quality System (HAWQS) platform. Five scenarios were examined with same parameter set, including 8- 12-digit codes, two levels HRU thresholds densities. Results showed that statistic evaluations monthly from 1983 2005 satisfactory at some gauge sites but relatively worse others when shifting 8-digit subbasins, revealing schemes vary across a large basin. Average channel slope drainage increased significantly subbasins. This resulted higher lateral flow groundwater estimates, especially for flow. Moreover, finer tends generate more because it captures refined level spatial variability. analysis datasets revealed denser produced predicted runoff, summer months.