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Water Models

About Water Models

Scientists in the Office of Pesticide Programs (OPP) in the Environmental Protection Agency (EPA) frequently use simulation models to predict pesticide concentrations in surface and ground water for use in both human health and aquatic ecological exposure assessments. Listed below are links to executable versions of each of the models currently in use, plus links to the documentation for these models.

Surface Water


Ground Water


Spray Drift


More Useful Links

SWCC (Surface Water Concentration Calculator)

The Surface Water Concentration Calculator (SWCC) estimates pesticide concentrations in water bodies that result from pesticide applications to land. The SWCC is designed to simulate the environmental concentration of a pesticide in the water column and sediment and is used for regulatory purposes by the USEPA Office of Pesticide Programs (OPP). The SWCC uses PRZM version 5.0+ (PRZM5) and the Variable Volume Water Body Model (VVWM), replacing the older PE5 shell (last updated November 2006), which used PRZM3 (Carousel et al., 2005) and EXAMS (Burns, 2003). This updated model will improve users' interactions with the program and facilitate maintenance and operation of the software.

KABAM Version 1.0 (Kow (based) Aquatic BioAccumulation Model)

KABAM is used to estimate potential bioaccumulation of hydrophobic organic pesticides in freshwater aquatic food webs and subsequent risks to mammals and birds via consumption of contaminated aquatic prey.

FIRST (FQPA Index Reservoir Screening Tool)

FIRST is a surface water model that is used to assess exposure to pesticides in drinking water.

FIRST Version 1.0

FIRST Models

FIRST Version 1.1.1

Tier I Rice Model

Tier I Rice Model is an aquatic model used to estimate surface water exposure from the use of pesticides in rice paddies.

PFAM (Pesticides in Flooded Application Model)

PFAM is an aquatic model used to estimate surface water exposure from the use of pesticides in flooded fields. In comparison to the current Tier 1 rice model, PFAM allows for more advanced evaluation of pesticide use on flooded agricultural areas such as rice paddies and cranberry bogs. The advanced capabilities of PFAM include accounting for water and pest management practices and for degradation in soil and aquatic environments, as well as for post processing of discharged paddy waters to a stream, index reservoir, farm pond, or other user-defined receiving water.

SCI-GROW (Screening Concentration In GROund Water)

SCIGROW is an aquatic model used to estimate pesticide concentrations in ground water.



AGDISP® (version 8.26) is a "first-principles" science-based model that predicts spray drift from application sites. The model was developed by the USDA Forest Service. AGDISP was designed to optimize agricultural spraying operations and has detailed algorithms for characterizing the release, dispersion, and deposition over and downwind of the application area. This model can be used in estimating downwind deposition of spray drift from aerial and ground boom applications. In addition, it can be used in estimating downwind deposition of spray drift from forestry and adulticide/mosquitocide applications. The research version of AGDISP® model can be obtained from Dr. Harold W. Thistle, USDA Forest Service.


AgDRIFT® (version 2.1.1), a modified version of the AGricultural DISPersal (AGDISP®) model developed by the US Forest Service, was created under a Cooperative Research and Development Agreement between the EPA, the US Department of Agriculture's Forest Service, and the Spray Drift Task Force. The AgDRIFT® model has the capability to assess a variety of spray drift conditions from agricultural applications and off-site deposition of liquid formulation of pesticides. This model can be used in estimating downwind deposition of spray drift from aerial, ground boom and orchard/vineyard airblast applications.

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