GIS TO ESTIMATE STORM-WATER POLLUTANT MASS LOADINGS

In order to develop a monitoring program for the Santa Monica Bay, Cal if., watershed, a landuse runoff model was developed using a geographi c information system (GIS) coupled with an empirical runoff model. The GIS/model has simple data requirements as compared to more complex mo dels that require routing information; and it is useful for predicting receiving-water loading on an annual basis or for single-storm events . Its approach can also be used to graphically present model results i n simple and intuitive ways that provide better insight to managers an d planners in evaluating pollution sources and control strategies. The GIS/model was used to locate monitoring stations in the most economic al way. The model predictions can be used to improve the evaluation of best management practices to control pollutant discharges. Receiving- water pollutant contributions from point and nonpoint sources can be c ompared to develop mom economical strategies for overall pollutant min imization.