Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Automated Geospatial Watershed Assessment Tool (Agwa): Uncertainty Analysis of Common Input Data 1797

item Semmens, D. - US EPA
item Goodrich, David

Submitted to: Federal Interagency Hydrologic Modeling Conference
Publication Type: Proceedings
Publication Acceptance Date: April 2, 2006
Publication Date: July 15, 2006
Citation: Levick, L.R., Guertin, D.P., Scott, S., Semmens, D.J., Goodrich, D.C. 2006. Automated geospatial watershed assessment tool (AGWA): Uncertainty analysis of common input data. Proc. 3rd Fed. Interagency Hydrologic Modeling Conf., April 2-6, 2006. Reno, Nevada. 2006 CDROM.

Interpretive Summary: This paper compares simulation results from the Automated Geospatial Watershed Assessment tool (AGWA) (Goodrich et al. 2006) and the KINEROS2 hydrologic model (Woolhiser et al. 1990) for the FAO, STATSGO and SSURGO soils datasets for 10m and 30m digital elevation model (DEM) resolutions on three different sized watersheds. The evaluation of these different soils and topographic data is important to worldwide applications of AGWA/KINEROS2. AGWA was originally designed to work with STATSGO soils. When the SSURGO and FAO soils datasets became available, they were incorporated into AGWA, but simulation results have not been compared using observed data. The results showed that the model performed reasonably well with either DEM and with both SSURGO and STATSGO soils at the smaller watershed scales. Results were poor for all combinations of soils and DEMs for the largest watershed, indicating there may be a problem with the model parameterization. Results for FAO soils were similar to SSURGO and STATSGO for the largest watershed, but showed that both runoff and peak flows were generally underestimated for the smaller watersheds.

Technical Abstract: The Automated Geospatial Watershed Assessment Tool (AGWA) is a GIS-based hydrologic modeling tool available as an extension for ArcView 3.x from the USDA-ARS Southwest Watershed Research Center ( and US-EPA BASINS website ( AGWA was designed to facilitate the assessment of land-use and climate-change impacts on water yield and quality at multiple scales. It parameterizes two watershed runoff and erosion models, the Kinematic Runoff and Erosion Model (KINEROS2) and the Soil and Water Assessment Tool (SWAT), using readily available topographic, soils, and land-cover data. After parameterization, the selected model is run through the AGWA interface, and results are imported back into the GIS for display and analysis. The goal of this study was to evaluate the effects of using different combinations of commonly available soil and topographic data on runoff volume and peak flow using KINEROS2. KINEROS2 was selected because it was designed to model relatively small watersheds, up to roughly 100 square kilometers. AGWA can obtain hydrologic parameters from three soils databases: the State Soil Geographic (STATSGO), Soil Survey Geographic (SSURGO), and Food and Agriculture Organization of the United Nations (FAO) digital soil map of the world. The three soil data types will be evaluated in combination with two USGS digital elevation model (DEM) resolutions: 10 and 30 meters. This paper will report the comparison of observed and simulated results from the six combinations of the three soil datasets and the two topographic datasets (DEMs).

Last Modified: 1/31/2015
Footer Content Back to Top of Page