http://h2osparc.wq.ncsu.edu/



           Water, Soil, and Hydro-Environmental Decision Support System



                             NCSU Water Quality Group
                           North Carolina State University
                          North Carolina Cooperative Extension
                   Department of Biological and Agricultural Enginering

                                      Cooperator
                     Center for AI Applications in Water Quality
                           The Pennsylvania State University
                   Agricultural and Biological Engineering Department

-> http://h2osparc.wq.ncsu.edu/GIS_AGNPS.html


Reference: WATERSHEDSS Grass-AGNPS Model Tool

Line, D.E., S.W. Coffey, D.L. Osmond. 1997. WATERSHEDSS Grass-AGNPS
Model Tool, Trans. of the  ASAE 40(4):971-975. 

Because much of the contamination of surface water is due to nonpoint source
pollution, protecting or
       restoring the designated use of a water resource often requires the
reduction of nonpoint source pollutant
       loading. Developing the most effective nonpoint source control
strategy for a watershed requires an
       understanding of the nature of the pollutants and the collection and
evaluation of a significant amount of
       pertinent information. WATERSHEDSS (WATER, Soil, and
Hydro-Environmental Decision Support
       System) was designed by Osmond et al. (1996) to aid users in learning
about sources, transport, and control
       of nonpoint source pollutants as well as in identifying the types of
data and tools needed to develop an
       effective control strategy. 

       The modeling tool in WATERSHEDSS uses the Agricultural Nonpoint
Source Pollution Model (AGNPS)
       developed by Young et al. (1994). In addition to automatically
computing input data from basic soils,
       topography, and land use maps, this modeling tool adds the capability
to input point source, channel
       characteristic, and pesticide application data for user-selected
areas in the watershed. The tool was used to
       simulate runoff and sediment, nitrogen, and phosphorus loads for a
small gaged watershed located in North
       Carolina. Output of the tool was compared to observed runoff and
pollutant loads for 11 storms. Statistical
       comparisons between observed and model-simulated loads at two
monitoring stations showed no significant
       difference between observed and predicted runoff volumes and
nitrogen, phosphorus, and sediment loads,
       indicating that the modeling tool provides reasonable estimates of
pollutant loads from storm events. 
