Newtown Creek CSO Storage Tunnel: Reducing CSO Events in Brooklyn & Queens

The New York City Department of Environmental Protection (DEP) is designing and plans to construct a combined sewer overflow (CSO) storage tunnel and related infrastructure to reduce the volume of CSOs entering Newtown Creek. Newtown Creek, located on the border of Brooklyn and Queens, is a tidal creek that flows into the East River.

The Proposed Project is part of an agreement formalized in 2005 between the City of New York and the New York State Department of Environmental Conservation to address CSOs. The DEP developed the Newtown Creek CSO Long-Term Control Plan (LTCP), which the state approved in 2018.

Project Purpose

• Reduce volume and frequency of CSOs into Newtown Creek
• Achieve water quality standards
• Construct new infrastructure
• Support Newtown Creek Superfund remediation goals

As part of the CSO agreement and the LTCP, wet-weather flows from the four largest CSO outfalls will be conveyed to the proposed 3.26-mile-long (5,250 meter), 22-foot (6.7 meter) internal diameter tunnel, with a storage volume of 50 million gallons (189,300 cubic meters). The proposed project includes constructing diversion facilities for the four outfalls to convey wet-weather flows to the tunnel, a gravity diversion sewer to connect the diversion facility to the tunnel, and a tunnel dewatering pump station (TDPS) and discharge pipe to convey stored sewer overflows to the Newtown Creek Wastewater Resource Recovery Facility.

Delve Underground, in a joint venture (JV) with Brown and Caldwell, was awarded the project and commenced work on August 22, 2022. The Final Basis of Design Report was issued on October 31, 2024, which presents the preliminary design. The JV team started the design phase of the project in fall 2024 and completed the 30% Design August of this year. The Project will be delivered through three design-bid-build Contracts. The three contract packages, along with anticipated construction milestones, are shown below.

The New York City Department of Sanitation (DSNY) Site Preparation (CP-1) work is required to prepare the site of the TDPS before the Tunnel and Diversion Facilities (CP-2) contractor mobilizes to the site to construct the shafts and excavate/construct the tunnel. Following demobilization of the CP-2 contractor from the DSNY site, the TDPS (CP-3) contractor will mobilize and construct the TDPS.