A HSPF Model Sensitivity Study: Impacts of Watershed Topographic Characteristics on Hydrological and Water Quality Modeling

Abstract

Better Assessment Science Integrating point & Non-point Sources (BASINS) is a popular tool for Total Maximum Daily Load (TMDL) modeling and management. The Hydrological Simulation Program - Fortran (HSPF) model, as a key component of BASINS, is widely used in hydrological and water quality modeling. This study explores the sensitivity of HSPF model to the watershed topographic characteristics used in hydrological and water quality modeling. The Wolf River Basin and Jordan River Basin in the Mississippi Coastal Watershed were divided into multiple sub-catchments using the BASINS watershed delineation tool. The ground elevation dataset was from National Elevation Data (NED). The land use / land cover dataset, Geographic Information Retrieval and Analysis System (GIRAS) was used as input data in HSPF to perform hydrograph calculation. Amongst these two basins, the Jordan River Basin has smaller average elevation, smaller elevation difference, and a larger coastal area (in this study defined where elevations are from 0 to 4 m); the Wolf River Basin has larger average elevation, larger elevation difference, and a less coastal area. The hydrological and water quality parameters including streamflow, water temperature, and dissolved oxygen were simulated for these two basins to see the sensitivity of HSPF to the watersheds’ topographic characteristics. The simulation relative errors for streamflow (daily), water temperature, and dissolved oxygen were 11.23%, 0.46%, and 7.86% respectively for the Wolf River Basin and 18.60%, 4.46%, and 21.81% respectively for the Jordan River Basin. Rugged topographic characteristics enabled Wolf River Basin simulation to have better results.