The White Oak Library, the Burtonsville Fire Station, the Dennis Avenue Health Center and the Sligo Creek Recreation Center have been chosen by representatives of the Montgomery County Department of Environmental Protection as sites for several low-impact systems, all of which aim to reduce stream pollution, severe erosion and damage to wildlife.

The four Montgomery County sites would use bio-retention, or rain gardens, which have water-loving vegetation and a special mix of soil to reduce pollutants as water filters through the area, said Derek Winogradoff, project manager and a Prince George's County environmental planner.

"If we integrate it well enough, you can hardly tell it's for stormwater management," he said.

Since these areas are designed to hold standing water for only four to six hours, and mosquito eggs need three days in water to hatch, there is no chance the rain gardens will become breeding grounds for the West Nile Virus, he said.

Other methods of low-impact development include building roof gardens and replacing street gutters with grass ditches and rough surfaces to reduce rapid stormwater runoff and give water a chance to evaporate.

"The smaller amount of water you collect at one location is easier to manage than a massive amount of water," Winogradoff said.

Demonstrations are a part of public outreach, which Winogradoff described as a "big component" of the effort, since people need to understand how damage to the watershed is a problem that will take cooperation to repair.

Workers at each site have been informed of the project, but nothing has been presented formally, said Craig Carson, a watershed planner with the county DEP.

"We haven't finalized anything yet," he said.

Low-impact development methods could potentially reduce liability associated with holding ponds and could be a popular way for developers to meet their stormwater management requirements, he said.

These methods could be particularly useful in cases where redevelopment is under way, since they take up less space and are less disruptive to existing structures like utilities, said Daniel Harper, a Montgomery County DEP senior engineer.

"Sometimes you're not able to build a storm pond in an older neighborhood that's pretty densely developed," Carson said.

University of Maryland researchers also will study whether the demonstration sites reduce pollution and runoff.

"If this proves to be a viable technology, then we have the opportunity to go back and enhance those structures to make them more environmentally sound," Harper said.

Some early studies have shown that these methods are extremely effective in removing metals and phosphorus from stormwater runoff, Winogradoff said.

The project was made possible by a $1 million grant from the U.S. Environmental Protection Agency and matching grants from Montgomery and Prince George's counties totaling $250,000 to build and study low-impact development projects in the Anacostia watershed.

The team members also have identified five sites in Prince George's County and four in Washington, D.C.

The efforts are part of a larger trend, officials said, and they consider it an important component to overall watershed improvement.

"We think it's going to be one of a group of tools in a toolbox," Harper said.