From the Stanford Model to BASINS: A Summary of Model Evolution

In the early 1960's the Stanford Watershed Model (SWM) was instrumental in introducing the civil engineering profession to the concept of continuous hydrologic modeling. With wide distribution and application of the SWM in the late 1960s, civil engineers recognized the value of digital continuous simulation for hydrologic applications. By the early 1970s the developers of SWM expanded and refined SWM to create the Hydrocomp Simulation Program (HSP), which also included general nonpoint source loadings and water quality simulation capabilities. Hydrocomp had demonstrated the utility of quantity/quality simulation by modeling a range of water quality constituents in a large basin. During the early 1970s EPA sponsored development of the ARM (Agricultural Runoff Management) and the NPS (Nonpoint Source) pollutant loading models to address pollution from agriculture, urban, and other land uses; the SWM approach was selected as the hydrologic foundation for an expanding suite of models of nonpoint pollution impacts. In the late 1970s EPA recognized that the continuous process simulation approach contained in all these models would be needed to analyze and solve many complex water resource problems. Grant money from the agency to Hydrocomp resulted in the development of the Hydrological Simulation Program - FORTRAN (HSPF), a non-proprietary system of simulation modules in standard Fortran that handled essentially all the functions performed by HSP, ARM and NPS, and was considerably easier to maintain and modify. HSPF simulates the hydrologic and associated water quality processes on pervious and impervious land surfaces and in streams and well-mixed impoundments. Since the first public release (Release No. 5) of HSPF in 1980, the model has undergone a continual series of code and algorithm enhancements producing a succession of new releases, leading up to the most recent Release No. 12 in 2001. Since 1981, the U.S. Geological Survey has been developing software tools to facilitate watershed modeling by providing interactive capabilities for model input development, data storage and data analysis, and model output analysis including hydrologic calibration assistance.