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| An illustration of the new bypass tunnel in 3-D rendering. |
Starting in 2013, the New York City Department of Environmental Protection will build a permanent three-milebypass around the leaking part of an aqueduct that supplies half the city's drinking water. The project is expected to take six years.
Completed in 1944, the Delaware Aqueduct is the world's longest continuous tunnel, and delivers more than 500 million gallons daily from four upstate reservoirs to customers in New York City and Ulster, Orange, Putnam and Westchester counties.
Since the 1990, DEP has been monitoring leaks of 15 million to 35 million gallons daily in part of the aqueduct that passes through relatively soft limestone where the aqueduct connects West Branch Reservoir in Putnam County to Rondout Reservoir in Ulster County.
The rest of the aqueduct traverses more durable rock formations made of sandstone, shale, gneiss and granite. However, there are several other areas along its route where more minor repairs can and will be made, at the point in the bypass construction project when DEP temporarily shuts down the Delaware Aqueduct.
DEP already has spent $300 million on project planning, and estimates that the bypass tunnel and internal repairs will cost about $1.2 billion. Additionally, the city water agency said it plans to spend another $900 million on "water projects to supplement the city's supply during part of the construction period."
