EPA has information about HSPF, but no longer has active support for HSPF as a standalone model. See also:



Also known as
Model type Modular
Model part of larger framework
Note on status model
Date note status model
Incorporated models or components:
Spatial dimensions 2D
Spatial extent Landscape-Scale, Watershed-Scale
Model domain Hydrology, Terrestrial
One-line model description a comprehensive package for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants
Extended model description Hydrological Simulation Program - FORTRAN (HSPF) is a comprehensive package

for simulation of watershed hydrology and water quality for both conventional and toxic organic pollutants (1,2). This model can simulate the hydrologic, and associated water quality, processes on pervious and impervious land surfaces and in streams and well-mixed impoundments. HSPF incorporates the 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. The transfer and reaction processes included are hydrolysis, oxidation, photolysis, biodegradation, volatilization, and sorption. Sorption is modeled as a first-order kinetic process in which the user must specify a desorption rate and an equilibrium partition coefficient for each of the three solids types.

Resuspension and settling of silts and clays (cohesive solids) are defined in terms of shear stress at the sediment water interface. The capacity of the system to transport sand at a particular flow is calculated and resuspension or settling is defined by the difference between the sand in suspension and the transport capacity. Calibration of the model requires data for each of the three solids types. Benthic exchange is modeled as sorption/desorption and deposition/scour with surficial benthic sediments. Underlying sediment and pore water are not modeled.


biogeochemistry, water quality,

Name Bob Bicknell
Type of contact Technical contact
Institute / Organization EPA
Postal address 1 Center for Exposure Assessment Modeling (CEAM)
Postal address 2 960 College Station Road
Town / City Athens
Postal code 30605-2700
State Georgia
Country United States
Email address
Phone 706-355-8403
Fax 706-355-8302

Supported platforms
Other platform
Programming language


Other program language
Code optimized Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development 1997
Does model development still take place?
If above answer is no, provide end year model development
Code development status
When did you indicate the 'code development status'?
Model availability
Source code availability
(Or provide future intension)
Source web address
Source csdms web address
Program license type Other
Program license type other --
Memory requirements This model system is designed for the IBM PC family of microcomputer or compatible systems running under version 3.30 or higher of the Microsoft or PC Disk Operating Systems (PC or MS DOS--refer to DEVELOPMENT SYSTEM section). Properly configured, this model system and its support files and programs can be executed under PC DOS or MS DOS 3.30 and later versions, DOS 4.0x, DOS 5.0x, or DOS 6.x.
Typical run time --

Describe input parameters Data needs for HSPF can be extensive. HSPF is a continuous simulation

program and requires continuous data to drive the simulations. At a minimum, continuous rainfall records are required to drive the runoff model and additional records of evapotranspiration, temperature, and solar intensity are desirable. A large number of model parameters can be specified although default values are provided where reasonable values are available. HSPF is a general-purpose program and special attention has been paid to cases where input parameters are omitted. In addition, option flags allow bypassing of whole sections of the program where data are not available.

Input format ASCII
Other input format
Describe output parameters 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 (e.g., 96-hour LC50).

Output format ASCII
Other output format
Pre-processing software needed? No
Describe pre-processing software
Post-processing software needed? No
Describe post-processing software
Visualization software needed? No
If above answer is yes
Other visualization software

Describe processes represented by the model HSPF assumes that the "Stanford Watershed Model" hydrologic model is

appropriate for the area being modeled. Further, the instream model assumes 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.

Describe key physical parameters and equations
Describe length scale and resolution constraints
Describe time scale and resolution constraints
Describe any numerical limitations and issues

Describe available calibration data sets SPF and the earlier models from which it was developed have been extensively applied in a wide variety of hydrologic and water quality studies (3,4), including pesticide runoff model testing (5), aquatic fate and transport model testing (6,7), and analyses of agricultural best management practices (8,9). An application of HSPF in a screening methodology for pesticide review is described by Donigian et al. (10). In addition, HSPF has been validated with both field data and model experiments, and has been reviewed by independent experts (11-20).

The Stream Transport and Agricultural Runoff for Exposure Assessment Methodology (STREAM) applies the HSPF program to various test watersheds for five major crops in four agricultural regions in the United States, defines a "representative" watershed based on regional conditions and an extrapolation of the calibration for the test watershed, and performs a sensitivity analysis on key pesticide parameters to generate cumulative frequency distributions of pesticide loads and concentrations in each regions. The resulting methodology requires the user to evaluate only the crops and regions of interest, the pesticide application rate, and three pesticide parameters -- the partition coefficient, the soil/sediment decay rate, and the solution decay rate.

The EPA Chesapeake Bay Program has been using the HSPF model as the framework for modeling total watershed contributions of flow, sediment, and nutrients (and associated constituents such as water temperature, DO, BOD, etc.) to the tidal region of the Chesapeake Bay (21,22). The watershed modeling represents pollutant contributions from an area of more than 68,000 sq. mi., and provides the input to drive a fully dynamic three-dimensional, hydrodynamic/water quality model of the Bay. The watershed drainage area is divided into land segments and stream channel segments. The land areas modeled include forest, agricultural cropland (conventional and conservation tillage systems), pasture, urban (pervious and impervious areas), and uncontrolled animal waste contributions. The stream channel simulation includes flow routing and oxygen and nutrient biochemical modeling (through phytoplankton) in order to account for instream processes affecting nutrient delivery to the Bay.

Currently, buildup/washoff type algorithms are being used for urban impervious areas, potency factors for all pervious areas, and constant (or seasonally variable) concentrations for all subsurface contributions and animal waste components. Enhancements are underway to utilize the detailed process (i.e. Agrichemical modules) simulation for cropland areas to better represent the impacts of agricultural BMPs and to include nitrogen cycling in forested systems to evaluate the impacts of atmospheric deposition of nitrogen on Chesapeake Bay. The watershed modeling is being used to evaluate nutrient management alternatives for attaining a 40% reduction in nutrient loads delivered to the Bay, as defined in a joint agreement among the governors of the member states.

Upload calibration data sets if available:
Describe available test data sets
Upload test data sets if available:
Describe ideal data for testing

Do you have current or future plans for collaborating with other researchers?
Is there a manual available? Yes
Upload manual if available:
Model website if any The HSPF User's Manual is available as a WordPerfect (version 5.1) document in (binary, non-ASCII) files HSPF_V11.001, HSPF_V11.002, HSPF_V11.003,

HSPF_V11.004, HSPF_V11.005, HSPF_V11.006, and HSPF_V11.007 in the DOCUMENT sub-directory. Refer to file READ.ME in the README sub-directory for further information on the storage format and printing requirements of the user's manual files.

Model forum / discussion board

This part will be filled out by CSDMS staff

OpenMI compliant No but possible
BMI compliant No but possible
WMT component No but possible
PyMT component
Is this a data component
Can be coupled with:
Model info
Bob Bicknell
Nr. of publications: 351
Total citations: 11177
h-index: 48
m-quotient: 1.12

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Nr. of publications: 351
Total citations: 11177
h-index: 48
m-quotient: 1.12

Featured publication(s)YearModel describedType of ReferenceCitations
Bicknell, B.R.; Imhoff, J.C.; Kittle, J.L.; Donigian, A.S.; Johanson, R.C.; 1993. Hydrological Simulation Program - FORTRAN (HSPF): Users Manual for Release 10.. EPA-600/R-93/174, , .
(View/edit entry)
1993 HSPF

Model overview

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Input Files

Output Files