The goal of this research is to develop a GIS-based model that identifies priority land areas for the management of water resources, with a particular focus on the effects of nonpoint source contaminants. The research is based in the headwaters region of the Credit River Watershed in southern Ontario. The Credit River Watershed is under mounting pressure to develop agricultural lands and natural habitat to accommodate a rapidly increasing population. Urbanization and high population growth rates are threatening the groundwater resources and the Credit River itself. The model developed here prioritizes land based on its potential to contribute sediment and nutrients to surface runoff, and its potential to transport nonpoint source pollution to water resources. It integrates land use planning and resource science at a regional scale by identifying the most significant land areas for the 'protection ' and 'restoration' of the Credit Valley Watershed's water resources.