Evaluating the Impact of Policy-induced Land Use Management Practices on Non-point Source Pollution Using a Spatial Decision Support System

Abstract

State and federal conservation compliance policies in the United States are aimed, in part, at reducing non-point pollution and maintaining long-term agricultural productivity. These policies affect land use and management practices on the nation's farms. Farms and farmers, however, are part of a larger agri-ecological system and changes in farming practices affect linked socio-economic, biologic, and hydrologic systems. It is difficult, therefore, to foresee the wide ranging and long-term consequences that are set into motion by changes in agricultural policy. Yet, these consequences must be understood if we are to avoid the deleterious side effects or capture the collateral benefits associated with specific policies. A Spatial Decision Support System (SDSS) has been developed here to help understand some of these consequences within the context of watershed management and the control of non-point source pollution. This SDSS consists of a Geographic Information System (GIS), two spatial models (GEOLP and AGNPS), and a graphical user interface. The purpose of this SDSS is to assist decision-makers as they investigate the impact of agricultural policy on non-point source pollution and the local economy. The SDSS is used to simulate the potential impacts of alternative policy scenarios in the Big Creek watershed. The models and methodologies described here, however, are general and can provide benefits to a variety of decision-makers engaged in watershed management and the reduction of non-point pollution.