Along with the familiar sights and sounds of summer, there’s a familiar smell of summer for those who live near the C&O Canal towpath.
It’s strongest on hot summer days, it packs particular punch along Cabin John, along the Clara Barton Parkway, and near Chain Bridge, and for at least two more years, it isn’t going away. But a collaboration of officials through a half-dozen jurisdictions intends to eat this odor once and for all.
OFTEN MISTAKEN as coming from the canal itself, the stench emits from vents in the Potomac Interceptor, a 50-mile sewer line running from Dulles Airport, under the Potomac River, then along the Maryland side of the river to a sewage treatment station in Washington, D.C. The smell is at its worst on very hot days when the sun bakes the sewage running through the massive pipe.
A plan to control the odor was released last fall by the D.C. Water and Sewer Authority (WASA) in conjunction with the National Park Service.
“Once again, it seems to be a slow process,” said Burr Gray, president of the Cabin John Citizens Association. “It’s a long haul … and they seem to keep moving forward.”
“We’ve never had air quality problems with a sewer this big,” said David Lake, assistant director in Montgomery County’s Department of Environmental Protection.
DESIGN OF FOUR proposed odor-control unit buildings has been the main item of contention over the past year. Because each is to be located on National Park Service land, the facades of each buildings must meet historical and aesthetic requirements of the National Park Service and the Maryland State Historic Preservation Office.
“That has taken some time,” said Lake. “You can’t build structures like this in six months… going through all the requirements of building [on] National Park Service property.”
Along the C&O Canal, this means designs must look historically authentic or similar to nearby construction. Current plans call for two of the blower units to be housed in buildings that look similar to lockhouses along the canal. Another site, that looks like a retaining wall is proposed for the intersection of the Clara Barton Parkway and the Beltway.
Costs for the project will be higher than estimated when the Environmental Assessment was first released, due to costs involved in making project buildings meet historical and architectural requirements.
“We’re on the final phases in the conceptual designs of the buildings,” said Kevin Brandt, assistant superintendent of C&O Canal National Historical Park. After building designs are approved by the park service and historic preservation office, the designs must also receive a “Finding of No Significant Impact” by the Park Service before construction can begin.
“That’s what we’re anticipating,” said Brandt.
Public comments tended to favor the location of one of the blower units near the Beltway/Clara Barton Parkway and opposed an alternative proposal for a unit near Lock 10 on the canal.
“The public overwhelmingly favored the location by the Beltway. It’s further away from the neighborhood [than the Lock 10 location],” said Brandt.
“It was not too far from some of the residential areas,” said Gray. “That’s what the community opposed, and it seems like the WASA folks were amenable.”
“My role in all of this is that we don’t want delays to hold up this project because of the [jurisdictional] transfers,” said Lake.
Meanwhile residents along the interceptor, in particular residents in the Village of Cabin John, feel they have suffered long enough.
“Some of the residents in Cabin John feel like they should be able to just close the vents,” said Gray.
Construction on the odor-control units is expected to begin next summer, the project slated for completion in spring or summer of 2005, according to a memorandum from John Trypus, a WASA project manager.
GEL BUCKETS ARE one means of temporary odor control implemented but WASA as the long-term plans go through an approval process in multiple jurisdictions. The stench can be minimized by hanging buckets in some of the more notorious vents in the Interceptor. Installation of carbon filters in the vents is another means to control the smell, but both of these methods require periodic replacement of odor-eating material. And they only go so far.
“During the majority of days of the year, they work,” said Lake. “On the worst days… those gel pots can only do so much.”
Lower temperatures and higher precipitation this summer has toned down the odor a bit, compared to near-perfect stench conditions last summer.
“To me it seems better than it has historically,” said Gray, who is optimistic that the project will be completed “as long as they don’t run out of money.”
A meeting will take place in the fall to inform the public of progress made in the odor-control plan, said Brandt.