More than 60 percent of U.S. land has been altered by urban development and agricultural use, recent studies estimate, and urban expansion claims an additional 420,000 acres of land each year. All land use affects the environment in some way, and unmanaged development can cause unforeseen environmental damage.
In an attempt to develop a comprehensive environmental management model for watersheds, Civil Engineering (CE) Associate Professor Panos Diplas is leading a team of 13 Virginia Tech researchers in a unique interdisciplinary assessment of the hydrologic, ecological and economic effects of urban development.
"The deterioration of the Chesapeake Bay is a classic example of unmanaged urban and agricultural evelopment," Diplas adds. "The goal of our project is to help local governments learn how to allow for urban development while sustaining good environmental quality." The project study site is the Upper Roanoke River Watershed.
The U.S. Environmental Protection Agency (EPA), in cooperation with the National Science Foundation, is sponsoring the three-year project with $850,000 in funding. The Virginia Tech team, consisting of faculty members from CE, agriculture and applied economics (AAEc), biological systems engineering (BSE), biology, fisheries and wildlife sciences, and the Virginia Water Resources Research Center (VWRRC), was one of four selected out of about 130 nationwide that submitted proposals.
The Upper Roanoke River Watershed has a drainage area of 512 square miles and includes both rural headwater areas and concentrated urban areas along the river's main stem. Located near the city of Roanoke, the watershed is experiencing significant residential and commercial development.
"A watershed is a self-contained environmental unit," says Diplas, who for several years has conducted research on environmental hydraulics, river flooding mitigation, wetlands and other related issues. "That makes it a good area in which to learn how to manage the effects of urban development."
Diplas and CE colleagues David Kibler, Richard Greene and Vinod Lohani, along with BSE faculty Saied Mostaghimi and Ram Gupta, will develop a hydrologic and hydraulic model for assessing the effects of different forms of urbanization on the quality and quantity of both surface water and groundwater.
The engineers will develop a model that can assess the environmental results of various types of land-use activities. For example, Diplas says, replacing forested land with a subdivision reduces an area's vegetative cover, which can increase flooding and levels of sediments, chemicals and other stream pollutants.
Researchers studying the watershed's ecological components -- biologists Fred Benfield and Prakash Nagarkatti and fisheries scientist Donald Orth--will develop procedures for predicting the responses of fish and macroinvertebrates to urbanization.
"Fish and smaller forms of stream organisms are sensitive to changes in factors such as streamflow and water quality," says Diplas. "They are excellent biological indicators of the effects of urban development. If their environment is deteriorating, eventually the effects will be felt by humans."
William Cox of CE, along with Leonard Shabman, Darrell Bosch and Kurt Stephenson of AAEc, will examine the relationship between public policy and development patterns and will estimate the effects of various forms of urban development on the values of agricultural, forest, residential and commercial land. They also will make assessments of tax receipts and fiscal costs incurred by local governments as the result of urbanization.
Understanding the balance between the environmental and financial issues of urban development is crucial to local officials and planners in making decisions, says Diplas. For example, he explains, deciding whether a subdivision should be zoned for one-half-acre or one-quarter-acre lots might require consideration of the effects on both streams and the community tax base.
The VWRRC and a committee of project researchers will oversee the integration of the hydrologic, ecological and economic models into a comprehensive model of all watershed elements. The Fifth Planning District Commission will help the Virginia Tech researchers form a panel of Roanoke-area stakeholders'local officials, state agency personnel, and environmental groups' to help ensure that the project reflects the interests and needs of watershed residents.
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For more information, media may contact Dr. Diplas at (540)231-6069 or pdiplas@vt.edu.