Streams, lakes, and bays may soon be cleaner thanks to an innovative approach to managing stormwater runoff being developed at Virginia Tech and funded by the U.S. Environmental Protection Agency (EPA).
A novel software application will help engineers and planners select
the most efficient and site specific methods — called "Best Management
Practices" (BMPs) — of controlling the amount of pollutants that enter
the receiving waters through stormwater runoff.
Pollutants are washed off the roads, parking lots, or other surfaces
by stormwater, and include toxic motor oil, pesticides, metals,
bacteria, and trash. The Congressional Research Service reported in
2007 that up to 50 percent of water pollution problems in the United
State are attributed to stormwater 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 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," says project coordinator Tamim Younos, water center associate
director and research professor of water resources in the Department of
Geography in the College of Natural Resources. Other project leaders
include Randy Dymond, CGIT co-director, and David Kibler, professor of
civil and environmental engineering.
Traditionally, the selection of BMPs has been done only by
proficient stormwater 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 stormwater runoff," explains Kevin Young,
research associate at CGIT.
Young adds that all too often personal bias has led to
"cookie-cutter" solutions to very complex stormwater management needs,
resulting in poor control of the pollutants.
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 stormwater is directed to a detention
pond where gravity takes over, depositing sediment and some pollutants
onto the bottom," says Younos. "Pond overflow that still may contain
dissolved pollutants reaches streams, rivers, and lakes, and possibly
groundwater."
Other types of BMPs are trenches and porous pavement that allow the
stormwater to infiltrate the ground, vegetated wetlands, and sand
filters that help sift the pollutants, or proprietary stormwater
technologies such as hydrodynamic separators.
The new tool will be pilot-tested on Town of Blacksburg’s storm
water system 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 stormwater runoff
pollutants.
"The best part about conducting a pilot test on Blacksburg is that
the town will be able to implement our recommendations," says Younos.
"We are very pleased by the town’s enthusiasm and support for this
project." Other stakeholders include the New River Planning District
Commission, Virginia Department of Environmental Quality, and Virginia
Department of Conservation and Recreation.
Young discussed the principles of this novel approach to managing
stormwater runoff in his Master’s thesis, under the guidance of the
late professor G. V. Loganathan.
The software, expected to be available next year, will be free for
use by all interested engineers and planners, localities, and BMP
review authorities, and will be applicable in other states with
geographic and climatic environments similar to Virginia.