Replacement of Anchorage Channel Water Siphons

Overview

The Anchorage Channel, an integral part of the shipping trade with access to New York Harbor and the rest of the Port of New York and New Jersey, is one of the most heavily used water transportation arteries in the world. Future cargo volumes are expected to double over the next decade and possibly quadruple in 40 years. The channel must be deepened to accommodate the new generation of cargo mega-ships, which have drafts that exceed 45 feet—the present depth of Anchorage Channel—and strengthen the City's ability to benefit from the likely increase in this economic sector.

Using funding authorized by the federal government, the Port Authority of New York New Jersey (PANYNJ), and the United States Army Corps of Engineers (USACOE), dredging operations proceeded to deepen the Anchorage Channel to 50 feet below mean low water over a length of 19,000 feet, from the Verrazano-Narrows Bridge to the channel's confluence with the Port Jersey Channel.

For PANYNJ and USACOE to complete their project, two water siphons (identified as Siphon #1 and Siphon #2) that are owned, operated, and maintained by the New York City Department of Environmental Protection, must be removed. These siphons are critical to ensuring a backup water supply to Staten Island and will be replaced by one new siphon at a deeper level. The new siphon is an approximately six-foot diameter siphon-welded steel water transmission main within a 12-foot diameter tunnel constructed beneath the New York Harbor between Brooklyn and Staten Island within a tunnel. Additional construction may include tunnel launching and receiving shafts, extensive land piping and sewer replacement and relocation, two micro-tunnel crossings beneath the Staten Island railroad, and a new chlorination station.

On behalf of the Department of Environmental Protection, NYCEDC managed the implementation of the project through the construction phase.

NYCEDC initiated construction of the Project in early 2011, which included a two-mile long tunnel between Brooklyn and Staten Island, within which a new 72 inch steel water main (the new siphon) was installed and completed in 2015. A significant upland piping work to connect the new siphon to existing water distribution systems in both Staten Island and Brooklyn was also installed and completed in 2017.The remaining scope of work primarily is finishing the chlorination station which chlorinates the water before it is pumped into the water distribution system.