DEP to rehab aqueduct

New York City Department of Environmental Protection (DEP) is beginning a multi-year, $158 million project to clean, repair, and upgrade 74 miles of the Catskill Aqueduct, which conveys water from the Ashokan Reservoir in Olive to the Kensico Reservoir in Westchester County. To allow workers to enter the concrete aqueduct tunnel, it will be shut down 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 was scheduled to begin October 29. 

The project has been developed in coordination with the communities where the work will take place, according to DEP. The 20 upstate communities that draw all or some of their drinking water from the Catskill Aqueduct have arranged to rely on backup water supplies during this year’s shutdown. New York City will use drinking water from its Croton System and Delaware System while the Catskill Aqueduct is out of service.

Up to 200 local laborers are expected to be employed during the shutdown periods. DEP will repair about eight leaks along the aqueduct and in connected chambers. Engineers will visually inspect the interior and use a remote-operated vehicle to examine two pressurized sections that will not be fully drained. 


This year, workers will test methods for cleaning the inside of the aqueduct, which involves scraping encrusted sediment from the lining to reduce friction that slows the water. The aqueduct had a carrying capacity of 660 million gallons per day when it was built and is now down to about 590 million gallons per day. Restoring about 40 million gallons of daily capacity will help New York City withstand a planned shutdown of the Delaware Aqueduct in 2022, when DEP will repair two major areas of leakage that have plagued parts of Newburgh and Wawarsing for decades.