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Comeback of Charles River depends on curbing runoff

Chicago has had success curbing urban runoff by utilizing “green alleys,” such as this one paved with permeable material.US environmental protection agency

Many Bostonians thought they’d never see children swimming in the Charles River, and the fact that the waterway was briefly open to public bathing this past summer showed how much progress there’s been in cleaning it up. However, the sight of kids frolicking in the Charles doesn’t mean all the river’s problems have been solved. Several environmental groups, including the Conservation Law Foundation and American Rivers, have petitioned the Environmental Protection Agency to close loopholes in regulations that allow for urban runoff from private entities with buildings built before the Clean Water Act of 1972. If Greater Boston wants to keep improving the swimmability of the Charles, the region needs to keep chipping away at the runoff problem. Fortunately, there are options.

Urban runoff is the process by which rainwater collects pollutants from city streets and then deposits them in local waterways. In less developed areas, this water soaks into the ground, where it is purified by natural processes. However, traditional cements are impermeable, so water that falls on them can’t be cleaned naturally before it collects in rivers and streams. The substances found in this runoff — which range from toxins from car exhaust to nutrients from lawn fertilizers — can dramatically change river ecosystems by poisoning aquatic life and causing huge increases in algae populations, tiny organisms that deoxidize the water after they die.


Boston should follow the lead of cities like Chicago that have found innovative approaches to this problem. In 2006, then-mayor Richard Daley launched the “green alleys” program, a plan to resurface Chicago’s 1,900 miles of alleyways with material that allows water to drain slowly through it. (Former Boston mayoral candidate Rob Consalvo’s proposal for sidewalks made of recycled tire rubber would have similar benefits.)

So far Chicago has installed over 100 green alleys. Coupled with strategically placed gardens that filter water, they have significantly reduced the urban runoff into Lake Michigan. To explore the green alley idea in Boston, Boston Architectural College — with support from the city’s Public Works Department — launched a pilot program in 2011 on Public Alley 444 in the Back Bay. According to Arthur Byers, the associate vice president of facilities at the college, preliminary results show that the alley was 100 percent effective at channeling rainwater into the ground for that last three weeks of June. Building off their success, the city has announced plans for its own project along similar lines.

The Charles is cleaner now than it has been in generations, but preserving and extending progress means putting imaginative solutions into practice. Green alleyways are only the beginning.