Application of the Water Erosion Prediction Project (WEPP) Model to simulate streamflow in a PNW forest watershed

Abstract

Assessment of water yields from watersheds into streams and rivers is critical to managing water supply and supporting aquatic life. Surface runoff typically contributes the most to peak discharge of a hydrograph while subsurface flow dominates the falling limb of hydrograph and baseflow contributes to streamflow from shallow unconfined aquifers primarily during the non-rainy season. The Water Erosion Prediction Project (WEPP) model is a physically-based, distributed-parameter, continuous-simulation model. Recent improvements to WEPP include enhanced computation of evapotranspiration (ET) by incorporating the Penman-Monteith method into the model, and improved calculation of subsurface lateral flow by properly setting a restrictive layer and soil anisotropic ratios. These modifications have substantially improved the performance of the WEPP model for forested watersheds. In order to further enhance the model applicability, a baseflow component needs to be incorporated to adequately represent hydrologic conditions where significant quantities of ground water flow to streams.

Citation

Srivastava, A.; Dobre, M.; Bruner, E.; Elliot, W. J.; Miller, I. S.; Wu, J. Q. 2011. Application of the Water Erosion Prediction Project (WEPP) Model to simulate streamflow in a PNW forest watershed. ISELE Paper Number 11040. Paper presented at the international symposium on erosion and landscape evolution; September 18-21, 2011; Anchorage, AK. 8 p.