ARS | Publication request: GIS-BASED GENERATION OF AGNAPS WATERSHED ROUTING AND CHANNEL PARAMETERS

Submitted to: Transactions of the ASAE
Publication Type: Proceedings
Publication Acceptance Date: August 10, 1997
Publication Date: N/A

Interpretive Summary: Water quality pollutant problems occur from agricultural sources throughout the U. S. Without the use of management tools, these problems are difficult to develop solutions for and understand. Computer simulation models have been developed to coordinate the processes which can occur on agricultural areas and provide answers for conservation management decisions. For large areas, the collection of necessary data for use in a model can be tedious, time consuming, and error-prone. This study presents technology that combines geographical information systems and model requirements to simplify and improve the accuracy needed in database development for large areas. An intuitive, graphical interface has been developed that leads users through the development steps needed to implement the water quality model, AGNPS. Channel characteristics can be derived for each area or cell simulated by the model. Each model cell requires an accurate determination by the interface of the channel's length, slope, orientation, and cross-section. This technology allows users to track pollutants, such as pesticides, fertilizers, or sediment, back to their source with minimal database management. By pinpointing the major pollutant sources, this technology helps planners in action agencies focus their corrective actions at those locations.

Technical Abstract: The development of input parameters for large watersheds needed by simulation models such as AGNPS, can be tedious, time consuming, and subject to human induced errors. Watershed models are an important tool in developing effective management plans to control runoff, sediment, and chemical pollution. Technology is needed that can simplify and reduce the effort necessary to generate input parameters required by AGNPS for large, ungaged watersheds. This study describes the integration of GIS and topographic analysis tools used to develop an interface with AGNPS and its continuous simulation version, AnnAGNPS. Watershed management tools are needed by agencies such as the USDA-NRCS for use in evaluating the effectiveness of alternative management practices to control erosion and other pollutant sources within a watershed system.