FREDERICKSBURG, VA (AP) It’s an unimpressive-looking patch of trees in an unimpressive location — behind a Chuck E. Cheese restaurant.
But the cluster of birch, dogwood and winterberry trees at the foot of the huge parking lot at Fredericksburg’s Central Park Mall is actually an embodiment of a new school of thought about stormwater and development.
The approximately 100- by 20-ft. (30.5 by 6.1 m) patch of trees is a “bioretention unit” meant to catch and filter storm runoff loaded with pollutants such as car fluids.
“This stuff is a toxic cocktail. Plants love it,” said Hal Wiggins, an environmental scientist with the U.S. Army Corps of Engineers in Fredericksburg.
A 2-ft. (.6 m) wide metal channel next to the trees is carefully engineered underground with layers of gravel and sand that filter and clean polluted water naturally and put it back into the ground. The system is a radical change from the retention ponds and pipes that have been used for storm water management the past two decades.
Wiggins, a disciple of low-impact development (LID), has been busy promoting it in one of the country’s fastest-growing regions.
He has helped put the Fredericksburg area at the forefront of low-impact development, encouraging its use in some major developments that require Corps permits where streams or wetlands are affected.
Water-quality experts say the new approach will protect the Chesapeake Bay and other water resources from pollutants being piped from retention ponds directly into streams and rivers.
That technique, used over the last 25 years, has deprived the ground of rainwater needed to recharge the water table, experts say.
“We’ve been disposing of the water and not thinking about how nature used the water to protect the aquatic resources,” said Larry Coffman, manager of the urban stormwater program for Maryland’s Prince George’s County.
Coffman, who is considered a pioneer of low-impact development, said the older system makes droughts and flooding worse.
“We change the hydrology by changing the water balance and screw things up,” he said.
While proponents praise Fredericksburg’s use of low-impact development methods, not everyone is rushing to make the switch.
Developers are still debating whether it costs more to build and maintain the natural-looking bioretention pits — also known as “rain gardens” — than the “pipe and pond” systems. Some say they worry about the loss of developable land, while others say research on the systems is too new and inconclusive.
Skeptics also include sprawl opponents who say the new methods encourage endless suburbia instead of forcing planners to limit growth.
Ed Risse, a Warrenton land-use consultant, calls low-impact development “a bad idea dressed up in green.” He said sprawl needs to be replaced with land-use decisions that set aside separate areas of countryside and condensed housing.
Land speculators, developers and builders profit from low-impact development, Risse said, but really helping protect watersheds requires minimal urban development.
Real estate developer Bill Vakos III said low-impact development isn’t something to rush into. His Fredericksburg company is talking with the Corps about whether to use the new method on a 256-acre office and commercial project in Spotsylvania County.
Vakos said he suspects the new method may cost more than the conventional pond system, and its merits haven’t been proved.
Other developers say building natural filtration pits will be cheaper than building retention ponds.
“Low-impact development was born out of a desire to save money,” said Neil Weinstein, executive director of the Low Impact Development Center in Beltsville, MD.
Wiggins and river advocate John Tippett have convinced some Fredericksburg area officials of low-impact development’s merits, putting the region on a par with the Pacific Northwest in being in the lead to embrace it, Weinstein said.
For example, Stafford County rewrote its construction code this year to allow for low-impact development practices.
Proponents say low-impact development may not eliminate sprawl, but it’s still better than the alternative.
“I don’t talk about LID in terms of controlling sprawl and traffic and schools. That’s not what it’s about,” Coffman said. Instead, he said, low-impact development “is trying to ensure we have the best technology possible to a make sure we protect our waters.”