DEQ briefs localities on quality of area streams
By Sean Tubbs
Thursday, March 15, 2012
Lodge Creek, Meadow Creek, Moores Creek and Schenks Branch are all considered to be impaired by the DEQ because they are not healthy environments for aquatic life. Fishing and swimming are prohibited.
As part of a plan to restore the streams, the DEQ hired the Biological Systems Engineering Department at Virginia Tech to identify pollutants in the watersheds of the four streams.
“We think sediment is the major stressor and if we can provide a suitable habitat for [microorganisms], that will allow them to come back,” said Gene Yagow, a senior research scientist at Virginia Tech. “We think these changes in sediment will get us there, and we will monitor the aquatic community to see if that happens.”
Sediment chokes off life by depriving habitats for microorganisms that make up the bottom of the food chain.
Yagow and his researchers calculated that over 3,200 tons of sediment enter Moores Creek every year, flowing in from stormwater that falls onto the waterway’s 21,860-acre watershed. The study is recommending that steps be taken to reduce that amount by 500 tons a year, or a 15.8 percent reduction.
“Everyone has seen a dump truck load of dirt being brought down a street,” said Tara Sieber, a water quality coordinator for the DEQ.
“One dump truck load is about 20 tons of dirt,” Sieber said. “Think about 160 of those trucks being transported down Moores Creek every year. Our goal for Moores Creek is to reduce that to about 135 trucks.”
The research found that Lodge Creek receives 177 tons a year of sediment; 577.3 tons a year flow into Schenks Branch and 1,587 tons enter Meadow Creek. Similar reductions are recommended for those waterways.
Sieber presided over a meeting Thursday to gather input from the public on the next stage of the clean-up process, which is to create an implementation plan to meet the sediment reduction goals.
Sediment is worsened due to impervious surfaces such as roadways or parking lots. When stormwater falls on them, sediment and other pollutants are carried swiftly into the watershed.
There are 1,665 acres of impervious surface in the Moores Creek watershed. The implementation plan will identify specific mitigation projects to help reduce sedimentation.
“The big question is how to address existing impervious surfaces that don’t have stormwater management,” said Greg Harper, the county’s water resources manager. “Retrofitting can be very expensive and I think we’re going to have to get creative in developing more incentives for stormwater management because much of the watershed is privately owned.”
Sieber said one example of a mitigation technique is a bio-retention filter — otherwise known as a rain garden.
“When rain moves off roads and parkways, the filters catch them in vegetated areas that look like swales in the ground,” Sieber said. “What that does is hold the water in place so it infiltrates into the ground without carrying the sediment. This can also filter out other pollutants such as nutrients.”
Current projects underway are one to restore the stream bank of Meadow Creek, rain gardens at Charlottesville High School and a green roof on City Hall. Albemarle County recently installed a bio-retention filter at the County Office Building on McIntire Road.
“Stormwater runoff from the parking lot used to deposit directly into Schenks Branch,” Harper said.
The DEQ’s local process, known as a “total maximum daily load,” is voluntary. That is in contrast with the federal Chesapeake Bay TMDL process, which has mandated specific pollution reduction goals be reached by 2025.
But Sieber said any progress made in the local plan would be a contribution to the bay TMDL.
“Everything we do in our yards to improve our backyards is going to improve things downstream,” Sieber said.
One local official was skeptical that these reduction targets are enough.
“It seems as though 15 percent is not enough to restore aquatic health, but I haven’t looked at the modeling,” said Liz Palmer, a member of the Albemarle County Service Authority. “I think it’s a good place to start, but I’d like to see more teeth behind it.”
Public comment on possible items to include in the implementation plan will continue through April 16. The implementation plan will be available for public review this summer.