Two Rock Creek residents call it an "engineers' marvel and an environmentalists' nightmare."
The county calls it erosion control.
The wall -- 50 yards long and 4 yards wide -- appeared "overnight" late last month across a Rock Creek tributary, said resident Darlene Schepleng. Known as a check dam, the wall slows storm water and soil flowing down the small, unnamed tributary from the Chesterfield town house subdivision.
County officials had told residents, concerned about erosion around the creek, that check dams were an option, said Schepleng, a longtime advocate of Rock Creek's cleanup. But, she added, she believed residents had vetoed their use.
"(Check dams) are a technical engineer's approach to an environmental problem," Schepleng said. "They are not an environmentally sensitive approach.
Schepleng said trees were lost to build the dam.
"It's a worse environmental problem than the one we tried to solve," she said. "It's like the Great Wall of China."
John Peacock, chief of environmental enforcement for the county Department of Inspections and Permits, saidthe check dam is the first of four planned for a quarter-mile of thetributary. The stream runs parallel to Edwin Raynor Boulevard between Mountain Road and Fort Smallwood Road.
Rock Creek's water quality has suffered for the past 15 years, a January 1990 report by the U.S. Environmental Protection Agency said.
Pollutants, running off construction sites, lawns, open fields and roads, have spurred heavy algae growth and suffocated other aquatic life, the report said.
Although the county adopted strict erosion-control laws in the 1980s, Chesterfield and several other Rock Creek subdivisions were built before the laws took effect, Peacock said.
"This one is particularly bad because of the sandy, erosive soils," Peacock said. "The purpose of the check dams is to break up the water, slow down its velocity andkeep the sediments in the same general area.
"Obviously, these things are not pretty, they are not pristine to look at," he said. "Naturally, for someone who remembers the way the stream used to look, it's an atrocity. But, from my standpoint, it's a necessity."
A consultant, Dames & Moore Engineering, recommended the dams in a storm water study of areas around the creek last year, said Vishnu Patel, project manager with the Department of Public Works. Check dams are constructed of stone and wire-mesh gabions.
The first dam, completed Jan. 25, cost $40,000 and was paid for by a Environmental Protection Agency grant, he said.
Patel said about $27,000 in fees collected from developers around Rock Creek will pay for the design and engineering of the remaining three dams. The county Department of Public Works also has requested $342,900 for the fiscal year beginning July 1.
Schepleng and resident Linda Dooley claim county officials lied to them, saying no check dams would be built. But Peacock said county officials always intended to use the check dams.
Peacock suggested the misunderstanding occurred because the county's left hand did not know what it's right was doing. "Someone in public works probably toldthem the project had stalled because there was no money in the budget for it, then someone else came through with the money," he speculated.
Dooley said she and Schepleng have fought for six years to have the county and the developer of Chesterfield dig out the eroded soil with shovels and wheelbarrows. But Peacock said the county does nothave the legal authority to order the developer to do that.
"A lot of wheelbarrows, shovels and manpower could be bought for a quarter-million dollars," said Schepleng, referring to the money for check dams.