The HSPF Model, Hydrologic Simulation Program Fortran, is a U.S. EPA program for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants. The HSPF model uses information such as the time history of rainfall, temperature and solar radiation; land surface characteristics such as land-use patterns; and land management practices to simulate the processes that occur in a watershed. The result of this simulation is a time history of the quantity and quality of runoff from an urban or agricultural watershed. Flow rate, sediment load, and nutrient and pesticide concentrations are predicted. HSPF includes an internal database management system to process the large amounts of simulation input and output. HSPF includes the source code, executable version, user's guide, and technical support.
HSPF, Hydrological Simulation Program-Fortran, is an EPA computer model that can simulate the watershed hydrology and associated water quality for both conventional and toxic organic pollutants on pervious and impervious land surfaces and in streams and well-mixed impoundments. The HSPF model incorporates the watershed-scale Agricultural Runoff Model (ARM) and Non-Point Source (NPS) models into a basin-scale analysis framework that includes pollutant transport and transformation in stream channels.
The HSPF model consists of a set of modules arranged in a hierarchical structure, which permit the continuous simulation of a comprehensive range of hydrologic and water-quality processes. Experience with sophisticated models indicates that much of the human effort is associated with data management. This fact, often overlooked by model builders, means that a successful comprehensive model must include a sound data management component. The HSPF software is planned around a time series management system operating on direct access principles. The simulation modules draw input from a Time Series Store and are capable of writing output to it. Because these transfers require very few instructions from the user, the problems referred to above are minimized.
The HSPF system is designed so that the various simulation and utility modules can be invoked conveniently, either individually or in tandem. A top-down approach emphasizing structured design has been followed. First, the overall framework and the Time Series Management System were designed. Then, work progressed down the structure from the highest, most general level to the lowest, most detailed one. Every level was planned before the code was written. Uniform data structures, logic figures, and programming conventions were used throughout. Modules were separated according to function so that, as much as possible, they contained only those activities which are unique to them. Structured design has made the system relatively easy to extend so that users can add their own modules with relatively little disruption of the existing code.
HSPF Interface - A new graphical user interface for HSPF has been added to WMS, the Watershed Modeling System.