Blacksburg, Va., watershed to host pilot test; release and free use expected in 2008
Streams, lakes and bays may soon be cleaner thanks to an innovative approach to managing storm water runoff being developed at Virginia Tech and funded by the U.S. Environmental Protection Agency (EPA).A new software application will help engineers and planners select the most efficient and site-specific best management practices (BMPs) for controlling the amount of pollutants that enter the receiving waters through storm water runoff.Pollutants including toxic motor oil, pesticides, metals, bacteria and trash are washed off the roads, parking lots and other surfaces by storm water. The Congressional Research Service reported in 2007 that up to 50 percent of water pollution problems in the United States are attributed to storm water runoff.The application is the product of collaboration between faculty and researchers from Virginia Tech's Virginia Water Resources Research Center, the Center for Geospatial Information Technology (CGIT) in the College of Natural Resources and the Via Department of Civil and Environmental Engineering in the College of Engineering.The new BMPs selection approach, called Analytical Hierarchy Process (AHP), will factor in dozens of site-specific criteria such as soil types, land slopes or maintenance accessibility before choosing the optimal BMPs for a particular location."This technique is expected to drastically reduce the BMP selection time and will also eliminate the human error from such a complex process," said project coordinator Tamim Younos, water center associate director and professor of water resources in the Department of Geography in the College of Natural Resources. Other project leaders include Randy Dymond, CGIT codirector, and David Kibler, professor of civil and environmental engineering.Traditionally, the selection of BMPs has been done only by proficient storm water experts guided by little more than vaguely written regulations, experience and intuition. "They rely heavily on past knowledge, tradition or even personal preference for particular methods of controlling storm water runoff," said CGIT research associate Kevin Young. He also a dded that all too often personal bias has led to "cookie-cutter" solutions to very complex storm water management needs, resulting in poor pollutant control.A widely used, conventional BMP is to build detention ponds near commercial or residential areas, regardless of the actual construction site needs and conditions. "The storm water is directed to a detention pond where gravity takes over, depositing sediment and some pollutants onto the bottom," said Younos. "Pond overflow that still may contain dissolved pollutants reaches streams, rivers and lakes, and possibly groundwater."Other types of BMPs include trenches and porous pavements that allow storm water to infiltrate the ground, vegetated wetlands, sand filters that help sift pollutants and proprietary storm water technologies such as hydrodynamic separators.The new tool will be pilot-tested on the storm water system in the town of Blacksburg, Va., and the local Stroubles Creek watershed. The AHP software will be used by the research team to select BMPs within the watershed contributing runoff to Stroubles Creek, the town's main receiving water body. Two existing computer models will then be used to simulate how efficient the selected BMPs are at removing the storm water runoff pollutants."The best part about conducting a pilot test on Blacksburg is that the town will be able to implement our recommendations," Younos said. "We are very pleased by the town's enthusiasm and support for this project."Other stakeholders include the New River Planning District Commission, the Virginia Department of Environmental Quality and the Virginia Department of Conservation and Recreation.The software, expected to be available next year, will be free for use by all interested engineers and planners, localities and BMP-review authorities. It will be applicable in other states with geographic and climatic environments similar to those of Virginia.