Appendix 2. The Chesapeake Bay Watershed Modt
program and special attention has been paid to cases where input parameters
are omitted. In
flags allow bypassing of whole sections of the
program where data are not available.
HSPF produces 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. Simulation results can be processed through
a frequency and duration analysis routine that produces output compatible with
conventional toxicological measures
Assumptions and Limitations
HSPF assumes that the "Stanford Watershed Model" hydrologic model is
appropriate for the area being modeled. Further, the
the receiving water body is well-mixed with width and depth and is thus limited to
well-mixed rivers and reservoirs. Application of this methodology generally
requires a team effort because of its comprehensive nature.
HSPF and the earlier models from which it was developed have been extensively
applied in a wide variety of hydrologic and water quality studies, including
pesticide runoff model testing, aquatic fate and transport model testing, and
analyses of agricultural best management practices. An application of HSPF in a
screening methodology for pesticides is described by Donigian et al. In addition,
HSPF has been validated with both field data and model experiments, and has
been reviewed by independent experts.