ECONOMIC AND ENVIRONMENTAL IMPACTS OF WATER-QUALITY PROTECTION POLICIES .1. FRAMEWORK FOR REGIONAL-ANALYSIS

Agricultural production systems provide some unique challenges for ass essing the regional impacts of water quality protection policies. A mo deling framework is proposed for assessing the environmental and econo mic consequences of groundwater quality protection policies at the reg ional level. The model consists of three components: (1) a crop simula tion/chemical transport model, (2) a regional economic optimization mo del, and (3) an aquifer groundwater flow model. The three submodels ar e linked and run recursively to simulate producer response to alternat ive water quality policies over a multiple-year time horizon. Model so lutions provide projections of production practices employed on variou s resource situations across the region. Economic evaluation of altern ative policies may he based upon regional agricultural income, crop pr oduction levels, input use, and changes in aquifer water levels over t ime. Measures of agricultural nonpoint source pollution provided by th e model include nitrate, phosphorus and pesticide loadings in deep per colation and runoff water, as well as sediment losses.