Prior to the development of sewer infrastructure, drainage from a storm event would shed from buildings and roadways and percolate back into the groundwater. As the area continued to develop, combined sewer systems were implemented to remove the water from the area. Building codes were adjusted and all drainage was to be put into the combined sewer system along with street runoff. New York City runs off of this combined sewer system, typically referred to as a CSO. An area of a neighborhood would have its drainage be directed to many drains and inputs within that specified area. This boundary is considered the limits of the CSO and all runoff and building sewage contributes to this system.
This differs from a regular sewer system because it combines sanitary sewage with storm run-off. The combination became too much for the pre-1930s system, when pervious ground cover decreased and population increased. This increased both the ground run off as well as the sanitary sewage load. History of our sewer systems The current factors cannot handle both of these loads and it gets backed up and overflows during large rain events.
The combined sewer system running through Gowanus is built to overflow. It has outfalls along the canal which deposit excess sewage, both storm water and sanitary, directly into the canal. While the overflow prevents back-ups into homes and streets, it has contributed to the pollution of the Gowanus, making it one of the most polluted waterways in the United States. While storm run-off has a direct path into street drains, roofs have more varying paths. Various drainage types include gutters, scuppers and internal drainage. The majority of small residential buildings use gutters, which feed to downspouts and then connect directly to the sewer. Larger more complex buildings have internal drainage systems. Large mid-rise and high-rise buildings have downspouts running through their interior walls, eventually combining in the basement
The Gowanus watershed is subdivided into sewersheds which are contributing to two water pollution control plants, Red Hook and Owls Head. These sewersheds are further divided into subsewersheds which overflow through their respective outfalls into the canal. Sub sewersheds in the Red Hook tributary are prefixed RH and the sheds in the Owls Head tributary are pre-fixed OH. There are ten subsewersheds which overflow into the canal: RH031, RH033, RH034, RH035, RH036, RH037, RH038, OH005, OH006, OH007. In order to study this complex system each sub-sewershed was looked at individually and treated uniquely.
/ Drawings
/ Project Team
Jonathan A. Scelsa, Jennifer Birkeland, Andrea Kelly, Giacomo Sartorelli
/ Project Collaborators
Andrea Parker - The Gowanus Conservancy
Architectural League of New York
/ Project Info
/ Project Type - Funded Research
/ Funding Agency - New York State Council of the Arts
/ Project Location - Brooklyn, NY
/ Project Date - 2016