2018-11-07 / Front Page

DEP announces start of $158 million Catskill aqueduct update

Project area includes Ashokan Reservoir to Westchester Cty.

New York — The New York City Department of Environmental Protection (DEP) has announced the start of a $158 million project to rehabilitate the Catskill Aqueduct, which has delivered drinking water from the Catskills to New York City for more than a century.

The multi-year project includes a variety of work inside the aqueduct and at connected facilities. These upgrades will happen on the northernmost segment of the 92-mile aqueduct, specifically the portion that carries water from Ashokan Reservoir in Ulster County to Kensico Reservoir in Westchester County.

DEP will rehabilitate this 74- mile stretch of the aqueduct by cleaning the inside and repairing a number of leaks, replacing 36 valves at chambers connected to the aqueduct, and performing other structural and mechanical upgrades to ensure proper function of the structure for generations to come.

To safely perform this work, DEP must shut down the Catskill Aqueduct annually for 10 weeks during the years 2018, 2019 and 2020. Each of the shutdowns will begin during autumn to coincide with the annual period of lowest demand on the water supply system. The first shutdown will begin October 29.

The Catskill Aqueduct Repair and Rehabilitation Project (CAT R&R) has been developed in close coordination with communities in the Hudson Valley where the work will happen, and with 20 towns, cities, villages and water districts north of the City that draw all or some of their drinking water from the Catskill Aqueduct.

Making preparations

DEP has been in regular communication with these communities to verify that their backup water supplies are ready to serve local residents and businesses during this year’s shutdown. For its part, New York City will rely on drinking water from its Croton System and Delaware System while the Catskill Aqueduct is out of service.

“The rehabilitation of the Catskill Aqueduct is one of the most important and complex water supply projects we have undertaken,” DEP Commissioner Vincent Sapienza said. “Engineers a century ago said the Catskill Aqueduct was built to last for ages, but we know their vision of longevity can only be achieved through periodic inspection and maintenance of our waterworks. The rehabilitation work that will happen over the next three years will go a long way toward securing the reliable flow of water to millions of New Yorkers well into the future.”

Work on the project began earlier this month as construction crews began to set up approximately 10 staging areas along the Catskill Aqueduct in Ulster, Orange, Putnam and Westchester counties. The project will employ 80-200 local laborers during the shutdown periods.

Once the aqueduct is shut down, workers will enter the massive concrete structure and adjacent facilities to perform the following tasks: DEP will repair approximately eight leaks along the cut-and-cover portions of the aqueduct, and at chambers connected to the aqueduct. Engineers will visually inspect the inside of the aqueduct and use a remote-operated vehicle to examine two pressurized sections of the aqueduct that will not be fully drained.

Staging areas, access roads

Staging areas and access roads will be improved for construction equipment and work that needs to be completed during future shutdowns. Workers this year will also test various methods for cleaning the inside of the aqueduct. The most effective of these methods will be used starting in 2019 when DEP will clean the concrete lining inside the aqueduct. This work will improve the transmission capacity of the aqueduct by reducing friction inside the conduit.

Historic records show the Catskill Aqueduct had a carrying capacity of 660 million gallons per day when it was built, but that has been reduced over time to approximately 590 million gallons. DEP expects to regain approximately 40 million gallons of transmission capacity in the Catskill Aqueduct by cleaning 59 miles of its interior. This additional capacity will help New York City withstand a planned shutdown of its Delaware Aqueduct in 2022.

DEP has spent much of the past decade planning for the Catskill Aqueduct rehabilitation in close coordination with communities north of New York City. DEP has received the appropriate permits from local government agencies to perform the work that is needed in their respective towns, villages and cities. It has also received state and federal permits for the work. These permits recognize that DEP will conform to all local ordinances related to work hours, noise and other considerations.

Upstate coordination

DEP has also worked closely with 20 communities north of the City who draw water from the Catskill Aqueduct. Because the aqueduct will not be available to these communities during the shutdown, DEP has stayed in close communication with their respective water departments to ensure backup supplies are available and ready to be activated. In recent days, DEP has confirmed that all these communities have an adequate source of water for their customers during the shutdown.

The Catskill Aqueduct generally carries about 400 million gallons of water each day to New York City from Ashokan Reservoir.

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