Separating pollution
In 1991, a lawsuit from the Conservation Law Foundation forced the city of Portland and the Portland Water District to begin addressing the sewer overflow problems. The city commissioned an engineering firm to create a master plan for eliminating 33 of the city’s 39 combined-sewer overflow sites in three phases of construction. Fifteen years after that plan’s adoption, the city is expected to finally finish the first phase in December. Casco Baykeeper Joe Payne, of the Friends of Casco Bay, blames the long delay on “a lack of diligent oversight” from Maine’s Department of Environmental Protection (DEP) and the federal Environmental Protection Agency (EPA). (For more, see “Don’t Expect Protection,” by Alex Irvine, July 16, 2004.) Given that more than 700 American cities have similar sewer-overflow problems, diligence may be too much to expect from the federal government. Even though overflowing sewers egregiously violate Clean Water Act standards, the official EPA policy on combined sewers requires only that cities have a plan to reduce sewer overflows and be working to implement that plan. Portland has arguably been satisfying those requirements, albeit very slowly. “But I believe there’s been a real change in attitude in the city,” says Payne. Payne is optimistic in part because the city council recently agreed to spend $61 million for phase two of the sewer improvements. These will include the closure of nine combined-sewer overflow sites in places like Back Cove, Capisic Brook, and the Fore River. Barry Sheff, a senior vice president of Woodard & Curran, an engineering firm working with the city on the sewer projects, says the general strategy of the project “will involve separation, going from a combined sewer to constructing infrastructure that separates the sewer into one pipe for storm drains, and one for sanitary sewers.” The so-called “sanitary sewer” will deliver raw sewage from indoor drains to the East End treatment plant, while the separated storm sewer will send runoff from streets to outlets at the nearest stream or shoreline. Dog feces, garbage, and other street grime will still flow into Casco Bay — but at least it won’t mix with raw human sewage quite as frequently. But the city’s sewer upgrades will also contain elements of what Sheff calls “low impact development” — things like man-made wetlands and retention ponds that can treat stormwater at the edges of parking lots, next to buildings, and even on rooftops, before the water reaches a drain. “The intent is to try and mimic pre-development conditions,” says Sheff. “There will still be outfalls because of the city’s impervious surfaces,” but as new streets and buildings are built throughout the city, they’ll be required to be constructed with methods that minimize runoff.
_CM | 