NY Mayor Bloomberg Helps Launch New York Harbor Siphons Project

Mayor Michael R. Bloomberg and Port Authority Executive Director Pat Foye on April 18 launched a $250 million construction project to boost economic development in New York Harbor. The project involves digging a new water transmission main – called a siphon – between Staten Island and Brooklyn that will allow for the removal of two existing tunnels that are currently at a much shallower depth. This will enable the dredging and deepening of the Anchorage Channel, a process that is critical to accommodate increased cargo volumes and larger vessels in future years.

The announcement was made on Staten Island at the site where the 110-ton, 300-ft-long Caterpillar TBM will soon begin drilling 100 ft underground. Over the next 10 months, the TBM will drill a distance of nearly 2 miles. The Mayor and Executive Director Foye were joined by Department of Environmental Protection Commissioner Carter Strickland, New York City Economic Development Corp. President Seth W. Pinsky and Staten Island Borough President James Molinaro.

“New York Harbor has been a critical part of our economy since the founding of our great city some 400 years ago,” Bloomberg said. “And if we want New York City’s economy to stay competitive, we must accommodate new mega-ships and their cargo. This investment in our infrastructure will spur economic activity all along our working waterfront.”

The Port of New York and New Jersey is the largest on the East Coast, and is the third-largest port in the country, providing more than 279,000 jobs to the local economy and $12 billion in annual wages.

To accommodate the dredging, a new drinking water transmission main must be installed beneath the Upper New York Bay between Brooklyn and Staten Island in order to replace two existing siphons, currently at depths of 56 and 60 ft. The new siphon will be at a depth of 100 ft. The Port Authority and DEP are splitting the project’s costs, with each contributing $125 million. The project is being implemented and managed by the New York City Economic Development Corp.

This new, larger 72-in. siphon is being built to replace two existing water mains connecting Bay Ridge in Brooklyn to Stapleton and Tompkinsville in Staten Island that will ultimately be removed during dredging. The new siphon, which will serve as the primary back up water feed for Staten Island, will provide 5 million gallons of daily water supply under normal conditions and up to 150 million gallons per day in emergency situations, ensuring a reliable supply of water for the nearly 500,000 residents of Staten Island. Staten Island uses approximately 50 million gallons per day of drinking water. The completion of the tunneling portion is expected in 2013, with the larger project slated for completion in 2014.

The primary water supply for Staten Island is the Richmond Tunnel, a 10-ft deep rock water tunnel placed into service in 1970. The city currently maintains two siphons to provide a back-up water supply for Staten Island through a connection beneath the Upper New York Bay to Brooklyn. The two existing siphons were built in 1917 and 1925, respectively, but they are too close to the final depth of the harbor and must be replaced since they could be disturbed during the planned dredging operations in the channel.

The new steel siphon, being built by a Tully/OHL JV, will be contained within a 12-ft OD excavated diameter tunnel at a depth of 100 ft. The EPB TBM, a first in NYC, will install 4-lf rings (2,360 total rings).

The siphon project also includes the construction of shafts in Brooklyn and Staten Island. The Staten Island shaft will be used to launch the TBM, and the Brooklyn shaft will be used to retrieve the machine. To connect the new siphon to the local water distribution network, the project will install 6,545 ft of new water mains in Staten Island and 1,710 ft of new water mains in Brooklyn.

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