Center for Exposure Assessment Modeling (CEAM) (EPA)
Johansen and others (1984) developed the Hydrological Simulation
Program - FORTRAN (HSPF) model to simulate both basin hydrology
and water quality. A continuous-time model, HSPF allows simulation
of contaminant runoff with instream water quality and sediment
interactions. The instream component includes not only nutrient
processes such as nitrogen and phosphorus movement, but also benthic
algae, phytoplankton, and zooplankton. The HSPF model also simulates
complex chemical processes including hydrolysis, biodegradation,
and oxidation. The drawback to HSPF is the data intensive nature
of the input parameters required. To ease parameter aquisition and model calibration an expert system for HSPF-parameters has been developed HSPF is capable of simulations
on basins as large as 68,000 square miles, and the watershed can
be subdivided into smaller subbasins.
Abstract on the CEAM - HSPF-page:
Hydrological Simulation Program - FORTRAN (HSPF) is a comprehensive package for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants. HSPF incorporates watershed-scale ARM and NPS models into a basin-scale analysis framework that includes fate and transport in one dimensional stream channels. It is the only comprehensive model of watershed hydrology and water quality that allows the integrated simulation of land and soil contaminant runoff processes with In-stream hydraulic and sediment-chemical interactions. The result of this simulation is a time history of the runoff flow rate, sediment load, and nutrient and pesticide concentrations, along with a time history of water quantity and quality at any point in a watershed. HSPF simulates three sediment types (sand, silt, and clay) in addition to a single organic chemical and transformation products of that chemical.