Replacement of Anchorage Channel Water Siphons

  • The tunnel boring machine (TBM) will drill a distance of 9,400 feet.
  • The locomotive will help transport workers and equipment, and move dirt.
  • The personnel carrier moves sixteen workers two miles to the TBM.
  • The TBM simultaneously drills and builds the tunnel, four feet at a time.
  • The TBM will be lowered to the bottom of the starter tunnel.
  • A crane lifts a reinforcing steel cage for the starter trench wall.
  • Crews bolt a reinforcing steel cage in place.
  • Crews lower a reinforcing steel cage into position.
  • This delicate process smooths the walls of the starter trench.
  • These brackets will hold massive steel girders to support the starter trench walls.
  • A chlorination building will provide clean drinking water.
  • The spinning wheels of the hydromill have dozens of steel teeth to rip through rock.
  • A clamshell bucket is used to scoop soil.
  • An excavator prepares the site.
  • Crews will pour concrete inside the plywood to create a guide wall.
  • Crews begin to excavate the starter trench.
  • Crews labor through the night.
  • Crews lower a reinforcing steel cage into position.
  • Crews pour concrete to make a section of the starter trench wall.
  • Crews will build a network of pipes to connect the new siphon to the water main system.
  • Heavy equipment at work.
  • Heavy equipment at work.
  • Orange fence marks the perimeter of the starter trench.
  • Punishing conditions take their toll on heavy machinery.
  • The spinning wheels of the hydromill have dozens of steel teeth to rip through rock.
Last Updated January 17, 2018

The new siphon will ensure a backup water supply to Staten Island and will facilitate the City's ability to benefit from anticipated increases in cargo volumes in the Port of New York and New Jersey.


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 more 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 are proceeding 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 proposed new siphon will be 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 will manage the implementation of the project through the construction phase.

Proposed Siphon Route

Proposed Siphon Route

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