The $2.6 billion project to reduce sewer overflows into D.C.’s waterways may be in for a big change, with a new proposal from DC Water to scrap tunnels in favor of green infrastructure for a wide swath of the city.
The first phase of the Clean Rivers Project is already underway and will consist of a massive underground tunnel to reduce combined sewer overflows to the Anacostia River. But the other principal segments, addressing overflows into the Potomac River and Rock Creek, would see a significant reduction in their tunnels under the proposal laid out by DC Water today. Instead, the authority would undertake a major process to install surfaces that could absorb water, like permeable pavements, rain gardens, and green roofs.
The tunnel adjacent to Rock Creek would be eliminated entirely; the water that would have been stored there in a big storm would instead be captured by green infrastructure in a section of the city stretching northeast from Petworth. Additionally, part of the tunnel alongside the Potomac would be scrapped and replaced with green infrastructure around Georgetown.
DC Water General Manager George Hawkins anticipates that the new proposal would deliver comparable results in terms of water quality, but would also reduce heat islands, improve quality of life, create jobs, and offer other advantages. “If you have comparable water-quality outcomes, then you start looking at what other benefits come with the expenditure,” he says. “There’s no question in our mind that green infrastructure delivers a whole host of additional benefits for the same expenditure.”
Hawkins says the new proposal would cost about the same amount, but the increase to ratepayers would be spread over a longer period, since the green infrastructure would be completed by 2032, versus the anticipated 2025 completion date for the tunnels under the existing plan. DC Water is exploring an option to provide financial incentives for homeowners to install their own green infrastructure, he says.
Because the Clean Rivers Project stems from a federal consent decree, the proposed modification will require approval by the Environmental Protection Agency, the Department of Justice, and ultimately a federal judge. Prior to that, DC Water is seeking public comment between now and March.
Advocacy groups such as the Washington Interfaith Network have been pushing DC Water to adopt a green infrastructure plan, but Hawkins says he’s been working on the proposal since he started his job more than four years ago. “The various advocates that advocate green infrastructure like the Interfaith Network have been very supportive,” he says, “but this is an initiative I’ve been interested in since I interviewed for the job.”
The revision process has included collaboration from all the relevant D.C. agencies, leaving the city with a better proposal, Hawkins says. “We’re so much more confident about what we’re proposing today,” he says.
Image from DC Water