Development of a GlS-based BMP Siting Tool for use inCoastal Virginia

摘要

Recently adopted Virginia regulations use the Runoff Reduction Method (RRM) to estimate runoff nutrient loads leaving a site before and after development. The regulations require one or more of an approved set of treatment controls, known as urban stormwater best management practices (BMPs) be used to reduce discharge loads. Coastal conditions limit the application of BMPs that comply with statewide specifications, farther complicating the BMP selection process. There is need for an objective tool that reduces complexity of BMP selection in the coastal plain that considers spatial variability, coastal conditions, altered design criteria, and uncertainty. This research summarizes the ongoing development of such a tool and its application in VirginiaBeach, VA. The tool uses Python as a framework to extract information from spatial layers. Spatial inputs include a digital elevation model (DEM) grid, a water table depth grid, and soil and drainage area (DA) boundary shapefiles. The hydrologic soil group, median slope, median water table depth, and total area of each DA is compared to a customizable constraint table. The tool results in a Microsoft Excel table which ranks the most appropriate BMPs by drainage area and soil type, making note of when relaxing certain design criteria permits use of the BMP. Unit cost and maintenance intensity are included in the output for information purposes. Inclusion of uncertainty is in development, and will use a Monte Carlo method. An example of the tool appliedto a proposed recreational amphitheater site in central Virginia Beach is provided.The abstract is often the only part of the paper to be read, so include your major findings in a useful and concise manner. Include a problem statement, objectives, brief methods, quantitative results, and the significance of your findings. The abstractshould be no more than 250 words long.