To Sponge Up Gowanus Muck
By Trudy Whitman
Gowanus Canal pollution. It’s not only about the decades and decades of industrial toxins that poured directly into the waterway. As anyone who lives near the notorious channel can attest, human waste also fouls the canal after heavy precipitation. And what can’t be seen are the ground-level contaminants, such as heavy metals, that flow down the streets into the canal during downpours and heavy snow melt. When sewer mechanisms cannot handle the additional flow, this gunk goes straight into the canal as well.
The Gowanus flushing tunnel when repaired — again — promises in 2013 to filter one-third of this fetid stew. But in 2008, dlandstudio, a local firm headed by Susannah C. Drake and composed of landscape architects and urban designers, proposed another partial fix that might go a long way in ameliorating the problems. It’s a Sponge Park made up of carefully selected greenery placed in key areas. The park’s plants would absorb and manage excess surface runoff — a process called phytoremediation — rendering the water’s edge a healthier place for public activity. The dlandstudio study was commissioned by the Gowanus Canal Conservancy. Since the concept was first introduced to the community, dlandstudio has been working out the details with a plethora of federal, state, and city agencies.
A Sponge Park team has now identified a test site, explained Yong Kim, Sponge Park project manager, at a Carroll Gardens Neighborhood Association meeting last month. Most agency approvals have been obtained, and the final authorizations are close at hand, according to Kim. After these are secured, a neighborhood-wide meeting to explain implementation will be arranged. Kim expects this meeting to happen early this year. With promised funding of approximately $800,000, construction could begin as early as spring 2012. The bulk of the expenses will be covered by the city’s Department of Environmental Protection; the remainder comes from a grant from the New England Interstate Water Pollution Control Commission. New York is a member state of this commission.
The test site will center on the area where 2nd Street meets the Gowanus Canal. Three curbside bioswales will be installed in a section of Bond and 2nd streets. By constructing false catch basins with the capacity of holding 3000 cubic feet of water, street flows will be intercepted, redirected, and cleaned naturally by grasses and flowering plants before being released into the canal. Many of the “first flush” toxins can be captured in this manner, Kim noted. The plants will be pruned regularly to eliminate contaminants, but experts estimate that they will also have to be replaced approximately every three years. Contaminated plants will be disposed of safely.
Guiding the thinking of the landscape architects and urban designers was the Gowanus Canal area’s original state as a wetland creek: “While the former marsh will not be restored to its 17th century state,” a dlandstudio press release states, “the plant communities and processes that historically helped control flooding and kept the Gowanus Bay clean will be reintroduced in a 21st century adaptation.”
If the 2nd Street test site works as well as the planners predict, these experts and the greater community can dream the bigger dream: the overall Sponge Park design introduced in 2008 calls for seven acres of esplanade, four-and-a-half acres of recreational open space, and three-and-a-half acres of permeable water remediation and retention area.
Susannah Drake, the dlandstudio president, is delighted the test site is close to realization. She said during a telephone conversion that she credits the Bloomberg administration for “making this happen.” The city worked very hard to “form allegiances” among the Departments of Environmental Protection, Transportation, and Parks and Recreation, she stressed. In fact, all concerned agencies are working harmoniously together.
“It’s kind of remarkable,” Drake concluded about the civic and governmental partnership.
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