Soil and Water Assessment Tool (SWAT)

The Soil and Water Assessment Tool (SWAT) is a public domain model jointly developed by USDA Agricultural Research Service (USDA-ARS) and Texas A&M AgriLife Research, part of the Texas A&M University System. SWAT is a small watershed to river basin-scale model to simulate the quality and quantity of surface and ground water and predict the environmental impact of land use, land management practices, and climate change.

Model components or inputs include: weather, surface runoff, return flow, percolation, ET, transmission losses, pond and reservoir storage, crop growth and irrigation, groundwater flow, reach routing, nutrient and pesticide loading, water transfer.

SWAT can provide the following:

  • Daily time step-long term simulations
  • Basins subdivided to account for differences in soils, land use, crops, topography, weather, etc.
  • Basins of several thousand square miles can be studied
  • Soil profile can be divided into ten layers
  • Basin subdivided into subbasins or grid cells
  • Reach routing command language to route and add flows
  • Hundreds of cells/subbasins can be simulated in spatially displayed outputs
  • Groundwater flow model
  • SWAT accepts output from EPIC
  • SWAT accepts measured data and point sources
  • Water can be transferred from channels and reservoirs
  • Nutrients and pesticide input/output
  • Windows Interface
  • GRASS GIS links to automate inputs


Publication Date: 2012

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Resource Types:

  • Modeling tool
  • Tool (general)


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