The conservancy’s mission is to steward the preservation, restoration, and green development of the canal and its environs. It focuses on developing water quality, ecosystem improvements, and public access. They want to bolster the community’s green infrastructure in the form of a “sponge” park that can capture and treat storm water runoff from the surrounding streets, while also providing public space to be enjoyed by the community.
Every year, the Gowanus Canal receives approximately 300 million gallons of mixed sewage and storm water through a mechanism called “Combined Sewer Overflows” or CSOs. The Combined Sewer system allows rain water and sewage to be mixed in the same pipes, the result of New York City’s aging infrastructure. Built in a time when it made sense to wash our sewage out to sea by allowing storm water to flow in the same pipes as sewage, CSOs occur at many points in the bodies of water surrounding New York City.
In the late 20th century, we figured out that it wasn’t a great idea to treat our rivers and streams as open sewers, so we built sewage treatment plants to purify our waste water. However, the combined sewer system remains, a legacy of the past. As a result, when the rains get heavy, instead of reaching the treatment plant, the system becomes overwhelmed with raw sewage and rain water, discharging directly into the canal. By creating porous areas and green spaces that absorb water into the earth, we are reducing the rainwater that enters the sewer system, limiting the amount of sewage overflowing into the canal.
The Degraw Street Gardens project is chiefly designed to reduce CSO volumes by trapping and treating storm water in the public right of way and keeping it out of the sewer system entirely. The right of way bioswales that will be designed for this project will sit in the sidewalks of Degraw and Nevins Streets and collect the water flowing down the street during rain storms. The added landscape will also reduce the heat island effect and cool off the adjacent buildings while providing shade for the passers-by. In addition to managing urban storm water, the project will bring much needed public green space to the Gowanus Canal waterfront, incorporating site amenities for local workers and community members as well as providing habitat and food sources for urban wildlife. Designed by KaN Landscape Design and managed by the Gowanus Canal Conservancy, this project will bring significant benefits to one of our nation’s most troubled waterways.