Assessing the Representativeness of Stream Geomorphology Parameters in Basins

The BASINS (Better Assessment Science Integrating point and Non-point Sources, Release 2) system, created under the auspice of the U.S. Environmental Protection Agency (EPA), uses An'Vie\\, as a framework to integrate several hydrologic/hydraulic and water quality models. The BASINS system also includes a national stream characteristic database that contains reach-scale data on mean stream width, depth and velocity, among other parameters. These data are used to calibrate the non-point source NPSM/IISPF model (Non-point Source Model/Hydrologic Simulation Program-Fortran) in BASINS. The objective of this research was to assess the representativeness of the stream characteristic data provided in BASINS. Geomorphological data collected at nine cross sections on Cazenovia Creek, NY were compared to stream geomorphologv parameters provided in the national stream characteristic database in the BASINS system. Cross sections were surveyed and velocity measurements were obtained during low-flow conditions in July 2001. Model runs were performed comparing observed flow in Cazenovia Creek during 1990 with (1) flow results front a calibration using the national stream characteristic database values of mean channel width, depth, and low-flow velocity and (2) flow results from a calibration using our measured values of mean channel width, depth, and low-flow velocity. Despite differences between the stream characteristic database data and our measured values of mean channel width, depth, and low­ flow velocity, model results were not different. Future work will investigate the effect measuring liighrrjlow events has on model results. INTRODUCTION quality assurance (Whittemore and Beebe, 2000). While BASINS was subjected to a minimal peer­ review in 1998, the national databases and default The U.S. Environmental Protection Agency parameters included in the system were not reviewed (EPA) has reviewed various modeling approaches (Whittemore and Beebe, 2000). and models that could be used for receiving water One national database component included analysis (EPA, 1995). One suite of models and in the BASINS system is a stream characteristic databases that came out of that review was the database, which contains reach-scale data on BASINS (Better Assessment Science Integrating variables such as mean channel width, depth, and point and Non-point Sources, Release 2) system. velocity for streams nationwide. The EPA compiled BASINS uses ArcView as a framework to integrate these data in 1982 from National Oceanographic and several hydrologic/hydraulic and water quality Atmospheric Administration (NOAA) aeronautical models, including the non-point source NPSMfHSPF charts at a scale of 1:500,000. The stream model (Non-point Source ModellHydrologic characteristic data, along with land use characteristics Simulation program-Fortran). BASINS was created and point sources data, are used to calibrate the under the auspice of the EPA primarily to provide a NPSMfHSPF model in BASINS. The objective of Total Maximum Daily Load (TMDL) assessment this research was to provide some quality assurance tool. Under the Clean Water Act, states are required and assess the representati veness of the stream to provide TMDL of pollutants from point and non­ characteristic data provided in BASINS. point sources (EPA, 1998). The BASINS system has become a popular, easy-to-use tool for water quality analysis; however, there are some questions of data