The CDM Smith – Mott MacDonald JV Reaches a Key Milestone at the Gowanus Canal in Brooklyn
News Item
The CDM Smith – Mott MacDonald JV Reaches a Key Milestone at the Gowanus Canal in Brooklyn
May 13, 2025
NEW YORK CITY— The CDM Smith – Mott MacDonald Joint Venture (JV) recently completed the excavation for the 8-million-gallon (30-million-liter) combined sewer overflow (CSO) tank in the Gowanus neighborhood of Brooklyn. This milestone marks a key advancement to support the New York City Department of Environmental Protection (NYCDEP) and showcases efforts to restore and revitalize the Gowanus Canal.
In 2022, the CDM Smith – Mott MacDonald JV was selected to serve as the construction manager by NYCDEP to coordinate and oversee the construction of the underground tank. The team is working closely with designers and contractors on-site to deliver the project under an accelerated schedule, while navigating the challenges of working in a highly urbanized area with soils contaminated by former industrial activities. When completed, the facility will intercept and store combined sewage that would otherwise overflow into the Gowanus Canal during periods of heavy rainfall.
With the mass excavation completed, the next phase of work will be the construction of the concrete tank structure, including interior permanent works, cast in place concrete and a roof slab which will cover the entire structure. The concrete work will be performed in parallel with the construction of ancillary influent and outfall structures, which will connect the tank to the existing Gowanus Pump Station and the Canal. The anticipated completion of this next phase of construction is early 2027.
The Gowanus Canal, a 1.5-mile-long waterway built in the 1800s to support industrial commerce, has a legacy of industrial pollution and contamination from combined sewer overflow outfalls. The completion of the Gowanus Canal cleanup will transform the neighborhood into a revitalized waterfront with open space and improved water quality for residents and visitors.
Much of the credit for achieving this major milestone goes to our dedicated field team which required working around the clock for 4-months to meet a very ambitious schedule.
“Much of the credit for achieving this major milestone goes to our dedicated field team which required working around the clock for 4-months to meet a very ambitious schedule,” said Brian Farrelly, construction manager at CDM Smith. “The teamwork and collaboration on this project are as good as it gets.”
CDM Smith is a privately owned engineering and construction firm providing legendary client service and smart solutions in water, environment, transportation, energy, and facilities. Passionate about our work and invested in each other, we are inspired to think and driven to solve the world’s environmental and infrastructure challenges.
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