The 1998 Clean Water Action Plan requires a cooperative approach to restoring and protecting water quality. Identification of watersheds with critical water quality needs, or "Unified Watershed Assessment" (UWA), is necessary. In Missouri, an interagency team used existing water quality information within a geographic information system to prioritize eight-digit hydrologic units. A criteria-based methodology allowed for categorization and weighting of UWA concerns. An ArcView GIS customized interface allowed the team to modify parameters and visualize results for the 21 criteria considered. This Dialog Designer interface was translated into JavaScript and linked with ArcView IMS to enable citizens to perform the analysis on the Web.