17/09/2024
Nicholson Construction and SBI Major Projects improve New York’s water quality
Nicholson Construction, as part of an internal JV with Soletanche Bachy International Major Projects, is involved in the Gowanus Owls Head Canal sewage disposal project in New York. Our teams are building a diaphragm wall for one of the two underground reservoirs, which will clean up the canal and improve water quality.
Located in Brooklyn, New York, the 155-year-old Gowanus Canal is 30.48 meters wide and 2.9 kilometers long. Originally a marshland tidal creek, it was dredged, straightened, and equipped with bulk headed as the surrounding area became more urbanized and industrialized. With these transformations, sewage and industrial waste began to be discharged directly into the canal untreated, leading to pollution and deterioration in water quality.
To restore water quality, the Gowanus Canal has been included in the U.S. Environmental Protection Agency’s “Superfund” program. As part of this program, the Department of Environmental Protection will build two Combined Sewer Overflow (CSO) tanks. These are infrastructures designed to manage wastewater overflows during heavy rains. They will intercept and store up to 45 million liters of wastewater, preventing untreated sewage from flowing directly into the canal in the event of bad weather.
The project
The project includes the installation of two subsurface tanks that will account for a third of the total storage capacity. Nicholson will build a 20,000 square meter diaphragm wall to facilitate the installation of a 15-million-liter combined sewage storage tank.
The diaphragm wall will provide NYCDEP (New York City Department of Environmental Protection) with a support for the excavation, as well as a groundwater cutoff wall. In fact, the owner wishes to have a separation wall in place to mitigate the risks associated with contaminants present on the site.
The wall will be installed at a depth of 64 meters, helping to limit the migration of contaminants on site and reduce the treatment time for contaminated groundwater. Nicholson will use a combination of two machines: clamshell and a Hydrofraise® to excavate the diaphragm wall panels. The work has been entrusted to Nicholson by Posillico Environmental, Inc. the general contractor for the project.
Brian Barkauskas, P.E., Vice President of Business Development for Nicholson Construction, said, “We are thrilled to be back in New York for this project that is so important to the community and the environment. Building on our long experience in all five boroughs, we look forward to another great project in Gowanus.”
Nicholson’s work on the project will start in September 2024 and will take around ten months to complete. Completion is now scheduled for May 2027.
