The Center for Sustainable Communities (CSC) at Temple University was engaged by the Pennsylvania Department of Environmental Protection to determine whether the ecological modeling approach known as ReVA (Regional Vulnerability Assessment) developed by the Environmental Protection Agency for large ecosystems or river basins could be applied at a much smaller scale for watersheds in Pennsylvania. The CSC chose the 57 square-mile Pennypack Creek Watershed (PCW) in southeastern Pennsylvania for this application. The CSC engaged a study team of scientists and researchers from universities, nonprofit organizations, and consulting firms to conduct this analysis. This report presents the results of this work. It includes a detailed assessment of the ReVA methodology and its applicability to the PCW, the preparation of a comprehensive Geographic Information System (GIS) database, the delineation of ecological indicators, the preparation of land-use scenarios, and the evaluation of the differential impacts of those scenarios on various watershed attributes.