Web-Based Low Impact Development Decision Support Tool for Watershed Planning

Abstract

Low Impact Development (LID) practices reduce pollution and hydrologic instability from stormwater arising from increases in impervious surfaces and land development practices. In response to increasing demands for information and tools to quickly and easily assess LID practices in comparison to conventional development practices, an easy to use web-based LID decision support and screening tool, L-THIA/LID, has been developed to evaluate the benefits of LID practices. The Long-Term Hydrologic Impact Assessment (L-THIA) web application is a decision support system based on the integration of web-based programs, geographic information system (GIS) capabilities, and databases. It provides information for decision makers on the impacts of water quantity and quality resulting from land use change. The web-based L-THIA/LID tool, which builds on L-THIA capabilities, will enable various stakeholders to quickly evaluate: (1) the impact of urban development on average annual runoff volume; and (2) the potential stormwater and pollutant reduction of proposed LID practices. Runoff quantity and water quality impacts of proposed land use change are displayed in tables, bar charts, and pie charts. The tool's aim is to enable decision makers the ability to evaluate and understand the effects of LID practices and thus support effective watershed planning to achieve desired stormwater management goals.