 |
Courtesy of The Washington Post, January 30, 2003
© 2003 The Washington Post Company
Occoquan Reservoir Is Clean, at Least for Now
By David Cho
Washington Post Staff Writer
Growth to the West Still Seen as Threat To Water Source
The Occoquan Reservoir, a twisting river that forms the border between Prince William and Fairfax counties, was so polluted during the 1960s and 1970s that the water people drank from it tasted and smelled dirty. Fish couldn't survive in its blue-green waters, the color of algae.
Today, the reservoir supplies clean, safe drinking water to 1.2 million Northern Virginians, a turnaround that local leaders say was remarkable in a region that exploded in development over the last 25 years.
Much of the reversal occurred because the sewage that flows into the Occoquan is purified by one of the most advanced treatment plants in the nation. Much is also because of controls on the explosive development.
In July 1982, the Fairfax County Board of Supervisors voted to restrict development on 41,000 of the 64,500 acres adjacent to the reservoir. The legislation, called a "downzoning" because it reduced the amount of development allowed in the area, was the first of its kind in the area to survive a court challenge. It amended zoning codes to limit developers from building more than one house on five acres, instead of the previous requirement of one house per acre.
Some environmentalists said, though, that development restrictions such as those in the Occoquan area are not the best way to use a county's land. Lee Epstein, director of the lands program for the Chesapeake Bay Foundation, said that clustering homes on small plots while leaving the surrounding land undeveloped is a better technique because it leads to less polluting storm-water runoff.
"The best [development] practices today are not the same that they were 20 years ago," said Epstein, a member of the original team of Fairfax County staff members who pushed for the downzoning in the early 1980s. "Today we would not call three-acre lots or five-acre lots particularly conserving of land. We would call them sprawl."
The best evidence that the growth limits had a positive effect on the quality of water in the Occoquan was the Occoquan Watershed Task Force's three-month study, released Monday. It reports that the Occoquan's tributaries in the downzoned area, such as Bull Run and Johnny Moore Creek, are far cleaner than streams in the western part of the region, such as Little Rocky Run or Cub Run.
When builders spread homes over wide swaths of land, Epstein explained, they have to add roads. Public transportation in such remote areas is nearly impossible, Epstein said, so residents have to drive their cars more. All of that leads to dirtier air and water that runs across asphalt and into streams.
"You end up, on a per-capita basis, creating a lot more pollution," he said. "The only way that someone living on that size lot can get around is to get in their car and drive a circuitous route to the local strip shopping center. So what you are doing is, you are building not just this house and its driveway, but the little connector streets and shopping centers, fire departments and everything else you need to connect those plots. It's pretty wasteful of resources."
David Bulova, co-chairman of the Occoquan Watershed Task Force, said he agreed that clustering homes in some areas of the county is in most cases better than downzoning land.
"You don't want to downzone everything, that doesn't make sense," he said. "But you can only cluster development where you can control it better."
Added Thomas J. Grizzard, director of the independent Occoquan Watershed Monitoring Laboratory in Manassas, which evaluates the river's water quality: "I get nervous when people start taking tools off the table. Every situation is unique. . . . You can't always say clustering is better than downzoning."
The downzoned area is just a fraction of the Occoquan watershed. Rain that falls anywhere within this huge basin -- an area of 590 square miles -- eventually collects in streams that flow into the reservoir, its lowest drainage point. The watershed covers parts of Prince William, Fauquier and Loudoun counties and the towns of Manassas and Manassas Park. About 17 percent of it, or roughly 64,500 acres, lies in Fairfax County.
Much of the watershed is already built to capacity. But ecologists said the reservoir is still threatened by the rapid pace of construction along the I-66/Route 50 corridor and along Route 28. More than 85 percent of the homes built in the Centreville area, for instance, were erected after 1980, the task force report states.
Such development harms water quality because when rainwater falls onto paved surfaces, it collects pollutants and carries them directly into storm-water basins and streams without allowing vegetation to absorb the chemicals first. Treatments for lawns and golf courses, as well as deforesting and building roads, also contribute to runoff.
The Occoquan receives about 25 million gallons a day of treated sewage directly from homes and businesses. A highly advanced recycling center filters the wastewater first. The plant is one of the major reasons the Occoquan is cleaner today, Bulova said.
Despite that technology, local ecologists need to keep a close watch on whether population growth will eventually lead to more sewage than the plant can handle, said Grizzard, head of the monitoring lab. Although water samples have not indicated any problems for now, the population in the watershed continues to climb, nearly tripling since 1978, when the plant was installed.
"Urban development is not completely responsible, but it's a tremendous contributor of runoff. Other sources are pollutants from humans living in the watershed," Grizzard said. "The key is to look at where new development takes place to enable jurisdictions to get ahead of the curve in planning for that development."
But getting local governments to address these issues together can be a "tough nut to crack," Grizzard said.
Normand Goulet, who manages Occoquan-related issues at the Northern Virginia Regional Commission, said, "We've been able to hold the line over the past several decades in terms of water quality," but he added that planning and cooperation for the entire watershed among the affected local governments will be the reservoir's greatest defense against pollution.