10-Year, $1.9B Westchester County Water Tunnel Project Breaks Ground

WESTCHESTER COUNTY, NY — The New York City Department of Environmental Protection just broke ground on a $1.9 billion water tunnel project in Westchester County.

The New York City Department of Environmental Protection (DEP) on Tuesday announced the start of the Kensico to Eastview tunneling and facilities upgrade project in Mount Pleasant. The project will be NYC’s largest water-supply tunneling effort in Westchester County since the 1940s, and its construction is expected to create hundreds of local jobs.

The new tunnel will run approximately 500 feet below ground and improve flexibility between vital water-supply facilities that serve more than 9 million people in NYC and Westchester County, according to officials.

The project is part of over $3 billion in capital commitments throughout Westchester County alone that will improve nation's largest municipal water supply system.

The centerpiece of the project, known as the Kensico-Eastview Connection (KEC), will be a 2-mile-long tunnel between Kensico Reservoir and the Catskill-Delaware Ultraviolet Light Disinfection Facility (CDUV) in Eastview. The new tunnel will provide an additional connection between the two components of the water supply system. Officials said the completed tunnel will give the DEP the ability to take other facilities out of service for periodic maintenance and inspection.

"Creating additional redundancy in our vital water supply system is an essential investment for the long-term resilience of the remarkable feat of engineering that provides more than 9 million New Yorkers with a reliable supply of pristine tap water," DEP Commissioner Rohit T. Aggarwala said. "This project will help us fulfill our commitment to providing consistent and reliable delivery of the highest-quality water to New York City and the growing population centers in Westchester County."

The first phase of construction includes site preparation at the DEP campus adjacent to the Kensico Reservoir, followed by the digging of two large shafts, 400-500 feet deep, the tunneling between the two shafts, and the addition of several new facilities and upgrades at the Kensico facility.

All phases of the project are expected to span a ten-year period with the new tunnel coming fully online by 2035.

The Kensico Reservoir stores approximately 30 billion gallons of water at full capacity. The DEP draws about 1 billion gallons of drinking water from the Kensico Reservoir each day to meet the demand of 8.6 million residents in the five boroughs of New York City and approximately 500,000 residents of Westchester County whose communities are connected to the city’s system.

As it moves towards the city, drinking water that leaves Kensico Reservoir is also treated at the CDUV. The new tunnel will stretch the approximately 2 miles from Kensico Reservoir to the CDUV in Eastview, the largest such facility in the world.

The finished tunnel will be 27 feet in diameter and run 400-500 feet below ground with a capacity to carry as much as 2.6 billion gallons of water each day, according to the DEC. The design plans account for future growth in the city and Westchester County, the potential addition of treatment facilities, and the need to periodically take other infrastructure out of service for maintenance or inspection, the agency said.

The project also includes new facilities and site work at both Kensico Reservoir and the CDUV. A century-old intake chamber at Kensico Reservoir will be upgraded and enlarged to draw water into the new tunnel, the reservoir's shoreline around that intake chamber will be improved to prevent sediment from escaping into the new tunnel, and the Kensico campus will receive utility, grading and drainage upgrades.

In addition, a new screen chamber to remove debris from the water will be constructed just north of DEP’s main campus at the reservoir, near Columbus Avenue in Valhalla, and the chemical addition systems at Kensico Reservoir will be upgraded to ensure the continued proper treatment of drinking water.

The DEP will also build a connection chamber at CDUV in Eastview to receive water from the new tunnel. Work at this site will also include several projects related to drainage, stormwater and utility improvements.

The Kensico Reservoir was built in 1915 as part of New York City’s Catskill Water Supply System. Kensico was later modified in the 1940s to also receive water from the city’s Delaware Water Supply System, also in the Catskills. Those two systems, collectively referred to as the Catskill-Delaware System, comprise the largest unfiltered water supply in the United States.

Also this year, the DEP is expecting to break ground on more than $1 billion in facility and infrastructure additions and improvements at Hillview Reservoir in Yonkers, which is the last stop for water from the Catskill reservoirs before it enters the water tunnels that feed the five boroughs.