Integration and Coupling of Hydrological Models with Water Quality Models:

Conceptual watershed model developed to examine water quality as it is affected by soil erosion from agriculture and urban areas (Young et al., 1987). AGNPS has three major components: hydrology, soil erosion and nutrient pollution. The hydrological function provides prediction of runoff volume and peak flow rate. The soil erosion function includes soil erosion and sedimentation. The nutrient function analyses nitrogen, phosphorous and chemical oxygen demand concentration in the runoff and sediment. The model requires a total of 22 parameters for execution. These include: Digital Elevation Model (DEM) aspect and slope, soil, land use, and point source information. The model calculates information on the basis of a cell. AGNPS is a single event model for a watershed no larger than several thousand square acres. AGNPS uses another USDA developed model named CREAMS (see below) to predict nutrient/pesticide and soil particle size generation, transport and interaction. Applications: According to the managers of the model, it has been used primarily for watershed water quality planning and for validation studies. Further it has been widely used at universities for educational purposes. Concerning European applications, the model has been downloaded in nearly every country in Europe; AUT, BE, CH, CZ, DE, DK, ESP, FI, FR, HU, IRL, IT, LTU, NL, POL, PRT, RUS, SVK, and UK. The model has been connected with a GIS-interface (GRASS) and in this version been applied in, e.g., IT and AUT. References: Bragadin et al. (1993), Fisher et al. (1997), Klaghofer et al. (1993), Rode and Frede (1997), Young et al. (1987)