Development of WinHSPF - An Independent, Fully Integrated Component of a Comprehensive Modeling System
Client: U.S. EPA Office of Science and Technology, Washington, DC
WinHSPF, an interface to the Hydrological
Simulation Program - Fortran (HSPF), is a key component of Better
Assessment Science Integrating point and Nonpoint Sources (BASINS)
Version 3.0. BASINS 3.0 is being developed for the U.S.
Environmental Protection Agency's Office of Water to respond to
the continued needs of various agencies to perform watershed and
water quality assessments integrating point and nonpoint sources.
In particular, BASINS supports the development of Total Maximum
Daily Loads (TMDLs), required under section 303(d) of the 1972
Clean Water Act for impaired waters.
Recognizing the need to estimate nonpoint source
(NPS) loadings under various environmental conditions, and to
combine them with measured or permitted point source (PS)
loadings, a watershed modeling system with appropriate databases
was integrated with a GIS platform operating on desktop PCs. A
continuous simulation model was considered to be an ideal choice
for a realistic representation of watershed processes. Continuous
simulation models combine daily (or other time-step) measurements
or synthesized estimates of effluent flows and loads, wet-weather
source concentrations and loads, and receiving water flows to
calculate receiving water concentrations; a deterministic model
applied to time series of these variables will predict
concentrations in chronological order in the same time sequence as
the input variables.
HSPF is a proven, tested continuous simulation
watershed model. It is one of the models recommended by the U.S.
EPA for complex TMDL studies. Being a batch program, the HSPF
model itself has no interactive user interface. Many user
interfaces have been developed for HSPF that make the model easier
to use, such as NPSM (contained within BASINS 2.0), and the GenScn
scenario generating software. WinHSPF builds upon the successes of
predecessor HSPF interfaces, but the design of WinHSPF provides
the user greater flexibility, with more advanced interactive
WinHSPF is completely independent of the BASINS
system and can be run stand-alone. At the same time it is a
fully-integrated component of the BASINS system. This system
architecture allows the user to choose the system environment that
best suits his/her needs. This design also allows a programmer to
enhance WinHSPF separately from the core BASINS system and from
the model algorithms.
Internally, WinHSPF uses an object-oriented data
structure linked to the HSPF model. WinHSPF works in such close
conjunction with HSPF that all features of HSPF are available in
WinHSPF. The object-oriented structure of WinHSPF allows for easy
development of graphical interface tools to view simulation
elements. These graphical tools help the user develop a deeper
understanding of the assumptions and abstractions inherent in
WinHSPF is currently distributed with BASINS.