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The Automated Geospatial Watershed Assessment (AGWA) tool is a GIS interface designed to help manage and analyze watershed water quantity and quality for novice to expert GIS users.

The Automated Geospatial Watershed Assessment (AGWA) tool is a Geographic Information Systems (GIS) interface jointly developed by U.S. Environmental Protection Agency, U.S. Department of Agriculture (USDA) Agricultural Research Service, and University of Arizona to automate the parameterization and execution of the Soil and Water Assessment Tool (SWAT) and KINematic Runoff and EROSion (KINEROS2) hydrologic models. The application of these two models allows AGWA to conduct hydrologic modeling and watershed assessments at multiple temporal and spatial scales. Current outputs are runoff (volumes and peaks) and sediment yield, plus nitrogen and phosphorous with the SWAT model. AGWA uses commonly available GIS data layers to fully parameterize, execute, and spatially visualize results from both SWAT and KINEROS2. Through an intuitive interface, users select an outlet from which AGWA delineates and discretizes the watershed using a Digital Elevation Model (DEM). The watershed model elements are then intersected with soils and land cover data layers to derive initial estimates of requisite model input parameters. AGWA can currently use STATSGO, SSURGO and FAO soils and nationally available land-cover/use data such as the National Land Cover Data (NLCD) datasets. Users are also provided the functionality to easily customize AGWA for use with any classified land-cover/use data. The chosen hydrologic model is then executed, and the results are imported back into AGWA for visual display on the spatially distributed model elements. This allows decision-makers to identify potential problem areas where additional monitoring can be undertaken or mitigation activities can be focused. AGWA can difference results from multiple simulations to examine and compare changes predicted for each alternative input scenario (e.g., climate/weather change, land-cover change, present conditions, and alternative futures). In addition, a variety of new capabilities have been incorporated into AGWA, including pre- and post-fire watershed assessment, watershed group simulations to cover all watersheds within a political or management boundary, implementation of stream buffer zones, and installation of retention and detention structures. A land-cover modification tool is provided for the development of prescribed land-cover change scenarios, with a number of options for uniform, spatially random, and patchy change to single or multiple land-cover classes. There are currently three versions of AGWA available: AGWA 1.5 for users with Environmental Systems Research Institute (ESRI) ArcView 3.x GIS software (ESRI, 2002), AGWA 2.0 for users with ESRI ArcGIS 9.x (ESRI, 2009), and AGWA 3.x for users with ESRI ArcGIS 10.x (ESRI, 2014). AGWA 3.x utilizes new features in ArcGIS 10.x that are not available in ArcView 3.x to make the tool more powerful, flexible, and easier to use than AGWA 1.5. However, all AGWA versions have been retained to reach the widest available audience.

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