Citation:

GUERTIN, P., D. GOODRICH, W. G. KEPNER, D. J. SEMMENS, M. HERNANDEZ, S. BURNS, A. CATE, L. LEVICK, AND S. MILLER. AUTOMATED GEOSPATICAL WATERSHED ASSESSMENT (AGWA): A GIS-BASED HYDROLOICAL MODELING TOOL FOR WATERSHED ASSESSMENT AND ANALYSIS. Presented at USGS US-Mexico Borderland Workshop, Tucson, AZ, March 20 - 23, 2007.

Impact/Purpose:

The primary objectives of this research are to:

Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;

Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;

Develop and validate multivariate models based on quantification studies;

Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;

Complete an initial draft (potentially web based) of a national landscape condition assessment.

This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.

Description:

The Automated Geospatial Watershed Assessment tool (AGWA) is a GIS interface jointly developed by the USDA Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona, and the University of Wyoming to automate the parameterization and execution of the Soil 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. AGWA's current outputs are runoff (volumes and peaks) and sediment yield.

AGWA uses commonly available GIS data layers to fully parameterize, execute, and visualize results from both the SWAT and KINEROS2. Through an intuitive interface the user selects an outlet from which AGWA delineates and discretizes the watershed using a Digital Elevation

Model (DEM) based on the individual model requirements. The watershed model elements are then intersected with soils and land cover data layers to derive the requisite model input parameters. AGWA can currently use STATSGO, SURRGO and FAO soils and national available NLCD, MRLC and GAP land cover/use data. Users are also provided the

capability to use their own soil and land cover/use data (Miller et al. 2007). The chosen model is then executed, and the results are imported back into AGWA for visualization. This allows managers 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 relative change from alternative of input scenarios (e.g. climate/storm change, land cover change, present conditions and alternative futures). The AGWA tool is being converted into an Internet-based service to provide ready access to environmental decision-makers,

resource managers, researchers, and user groups (Cate et al. 2006). In addition, a variety of new capabilities are being incorporated into AGWA (Goodrich et al. 2005; Goodrich et al. 2006). They include handling FAO soils for international application; pre- and post-fire watershed assessment options for user defined land cover change; implementation of stream buffer zones; simulation of nitrogen and phosphorus movement; and installation of retention and detention structures. AGWA is currently being used for watershed assessment and to support

watershed planning. Applications include watershed-based planning for the Arizona Department of Environmental Quality; assessing the impact of energy development in Wyoming; assessing the impacts of landscape change in New York, Arizona, Oregon and Virginia (Miller et al.

2004); and analysis for alternative futures in the San Pedro River, Arizona (Kepner et al. 2004). For more information on AGWA visit the AGWA website located at:

http://www.tucson.ars.ag.gov/agwa/.

Record Details: