Soil & Water Assessment Tool

SWAT is the acronym for Soil and Water Assessment Tool, a river basin, or watershed, scale model developed by the USDA Agricultural Research Service (ARS). SWAT was developed to predict the impact of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use and management conditions over long periods of time. To satisfy this objective, the model is physically based requiring specific information about weather, soil properties, topography, vegetation, and land management practices occurring in the watershed. The physical processes associated with water movement, sediment movement, crop growth, nutrient cycling, etc. are directly modeled by SWAT using this input data. SWAT is a continuous time model that operates on a daily time step at basin scale. The model is not designed to simulate detailed, single-event flood routing.

Website: http://swat.tamu.edu/

Licence: Open source

Operating System(s): Windows, Linux (only without GUI)

Modelled processes...


  • Santhi, C., R. Srinivasan, J.G. Arnold, J.R. Williams (2005): A modeling approach to evaluate the impacts of water quality management plans implemented in a watershed in Texas. Environmental Modelling & Software. 21 (2006): 1141-1157.
  • Gassman, P.W., M. R. Reyes, C. H. Green, J. G. Arnold (2007): The Soil and Water Assessment Tool: Historical Development, Applications, and Future Research Directions. Transactions of the ASABEVol. 50(4): 1211-1250.
  • Dile, Y.T., P. Daggupati, C. George, R. Srinivasan, J. Arnold (2016): Introducing a new open source GIS user interface for the SWAT modelEnvironmental Modelling & Software. Vol. 85, November 2016, Pages 129-138, ISSN 1364-8152, DOI:10.1016/j.envsoft.2016.08.004.