NASA-Modified Precipitation Products to Improve USEPA Nonpoint Source Water Quality Modeling for the Chesapeake Bay

摘要

The USEPA has estimated that over 20,000 water bodies within the United States do nor meet water quality standards One of the regulations in the Clean Water Act of 1972 requires states to monitor die total maximum daily load, or the amount of pollution that can be carried by a water body before it is determined to be "polluted," for any watershed in the United States (Copeland. 2005) In response to this mandate, the USEPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a decision support tool for assessing pollution and to guide the decision-making process for improving water quality One of the models in BASINS, the Hydrological Simulation Program Fortran (HSPF). computes continuous streamflow rates and pollutant concentration at each basin outlet By design. precipitation and other meteorological clam from weather stations serve as standard model input In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events, especially if they are few and far between An attempt was made to resolve this issue by substituting station data with NASA-modified/NOAA precipitation data Using these data within HSPF, streamflow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better streamflow statistics and, potentially, in improved water quality assessment