You may not feel it, but major developments are afoot in the city’s water supply.

New York City is preparing to close down a massive—and leaking—aqueduct which delivers over half of the city’s drinking water from upstate reservoirs, more than 120 miles to the north.

The billion-dollar, multi-year repair work on the Delaware Aqueduct is the “central component” of the city’s Water for the Future program, which “aims to ensure clean, safe and reliable drinking water for future generations of New Yorkers.”

On Friday, the city announced that blasting had begun in Wappinger, N.Y., on the Dutchess County side of a new tunnel that will permanently bypass a leaking section of the aqueduct.

The 85-mile long Delaware Aqueduct conveys drinking water from four major reservoirs in the Catskill Mountains -Cannonsville, Neversink, Pepacton and Rondout- to the city’s water distribution system.

The city says that, on average, the Delaware Aqueduct provides more than half of the approximately 1 billion gallons of drinking water consumed by New Yorkers every day. The aqueduct, reportedly the world’s longest continuous tunnel, was constructed between 1939 and 1944 and crosses Ulster, Orange, Dutchess, Putnam and Westchester counties.

New York City’s water supply system is used by more than 9 million people, including 8.4 million in the five boroughs, along with residents of Ulster, Orange, Putnam, and Westchester counties.

City water comes from the Catskill, Delaware, and Croton watersheds.

Leaking Millions of Gallons Per Day

The Department of Environmental Protection, which manages the water supply system, has been monitoring two leaks in the Delaware Aqueduct since the 1990s. The leaks—located in Newburgh and Wawarsing—release a combined 15-35 million gallons a day, “depending on the rate of flow inside the aqueduct.”

To address the leaks, DEP has begun construction of a 2.5-mile bypass tunnel that will run 600 feet below the Hudson River, from Newburgh to Wappinger. The bypass tunnel, which is scheduled for completion in 2021, will convey water around the leaking portion of the Delaware Aqueduct in Newburgh.

DEP spokesman Adam Bosch told NYER that the aqueduct would be shut down for about eight months in 2021, in order to drain it and connect it to the bypass.

What Will Happen When the Delaware Aqueduct is Closed?

Delaware Aqueduct bird’s-eye view. Click here for a larger version.
Delaware Aqueduct bird’s-eye view. Click here for a larger version.

The city says that it has developed a “portfolio” of projects that “will ensure New York City has high-quality and reliable drinking water while the aqueduct is out of service.” This portfolio includes rehabilitating water supply sources used by the city in the past.

The 74-mile-long Catskill Aqueduct, which delivers water from the upstate Ashokan and Schoharie reservoirs, will undergo a repair and rehabilitation project starting in 2016.

The city plans to increase the tunnel’s capacity by approximately 30-40 million gallons of water each day.

For additional water supplies, DEP will also rehabilitate the Queens Groundwater System, formerly the Jamaica Water Supply, which will “sustainably provide more than 33 million gallons of water a day in southeast Queens”.

Groundwater in Queens? Is it safe to drink?

DEP has “committed to using proven technologies to ensure these wells produce high-quality water that meets or exceeds all water quality standards”. The Queens Groundwater System consists of 68 wells at 48 separate well stations.

Another highly complex and expensive project, the new Croton Water Filtration Plant, is entering its final stage of construction in the north Bronx. The city says testing of the filtration system and water lines is nearly complete.

Once online, the filtration plant will allow New York City to again use water from reservoirs in Putnam and Westchester counties that are part of the Croton System. DEP says this will provide nearly 300 million gallons of “high-quality” water each day.

And New Yorkers will have to start thinking more seriously about water conservation.

Between now and the shutdown of the Delaware Aqueduct in 2021, DEP will implement several initiatives to reduce water consumption in the city by as much as 50 million gallons a day.

Water conservation tools –like activation buttons on spray showers- will be rolled out in city parks and public schools. The city is also developing incentives to encourage water conservation in private homes and hotels.