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Land Matters: A Watershed for a Watershed

We’ve had a qualified breakthrough for green stormwater infrastructure here in Washington, D.C., recently in the long push to clean up our rivers and the Chesapeake Bay. Washington is one of hundreds of cities since the 1990s that the U.S. Environmental Protection Agency has said needs to fix its combined sewer overflow so that sewage no longer mixes with stormwater and surges into waterways, in our case the Potomac and Anacostia Rivers and also Rock Creek, when we have heavy rain. About a third of the city has combined sewers, the last of them built about a century ago. There are 47 places where D.C.’s sewage overflows into open waters. The Anacostia, in recent years, has been likened to a septic tank.

Under a 2005 consent decree agreed to by the city, the District of Columbia Water and Sewer Authority (DC Water), the EPA, and the U.S. Department of Justice, the proposed solution to this problem, similar to approaches in Atlanta, Portland, Seattle, and numerous other cities, has been to dig a system of deep tunnels to hold excess stormwater apart from sewage until it can be treated by DC Water and pumped out into the Potomac River mostly clean. This system, well under construction now along the Anacostia banks, involves 13 miles of tunnels sunk 100 feet underground at a cost of nearly $3 billion. I call it the subway for stormwater. It would lower toxic overflows by 96 percent in an average year over current levels. (The current overflow volume is estimated to be 40 percent lower than it was in 1996, owing to new controls.)

But the tunnel idea, though it would furnish a needed remedy with relative speed by 2025, has been a shunt rather than a focus on the chronic city problems of too much pavement and other impervious surfaces. In 2009, a new general manager and CEO at DC Water, George S. Hawkins, began to explore the potential of a green stormwater infrastructure system of bioswales, pervious pavings, rain gardens, and green roofs to prevent or reduce combined sewer overflows. In early 2014, DC Water floated a proposal to modify its consent decree with the EPA to allow it to install green infrastructure and cut back the scope of the tunnel projects. The modification would delay full compliance with the consent decree by five to seven years, which does not thrill environmentalists.

“Every year that we accept raw sewage being dumped into the water of our nation’s capital is completely unacceptable,” as an attorney for the public interest law office of Earthjustice, Jennifer Chavez, told the Washington Post. Local and national environmental advocates, led by Earthjustice, had filed suit against the city in 1999 to begin cleaning up the sewage overflows. Those advocates, who have been monitoring progress under the 2005 consent decree, support the idea of green infrastructure as long as it in no way delays or reduces the decree’s aggressive pollution reduction deadlines. They received the modification proposal to the tunnel projects with intense wariness, citing in a letter in April 2014 a number of major shortcomings and a general lack of specifics in the utility’s projections for green infrastructure’s performance.

The EPA and the Justice Department approved DC Water’s modification plan on May 20, in what green infrastructure advocates could call a victory. The plan to build several miles of tunnel in the Anacostia watershed is unchanged, but one smaller tunnel would be eliminated and another considerably reduced in scope if green infrastructure turns out to do the trick. DC Water is calling it a “hybrid” approach. But there are still reservations among environmentalists about its efficacy. They will continue to insist that green infrastructure projects must reduce overflows by at least as much as the tunnels, and they wonder—as any landscape architect naturally would—who is going to maintain all this green infrastructure throughout the city and make sure it operates properly. This is going to be a major test case of a grand plan to bring something like “nature” back to a city, and if it works, terrific. If it doesn’t work, it will be Exhibit A for the skeptics.

Bradford McKee
Landscape Architecture Magazine Editor

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