History of New York’s Watershed

The long and tumultuous story of the development of New York City’s water supply, West of the Hudson River, began when the New York State Legislature passed Chapter 724 of the Laws of 1905, an act allowing the city to acquire lands and build dams, reservoirs, and aqueducts in the Catskills.

The city had already claimed the Croton River watershed in Putnam and Westchester Counties east of the Hudson, drawing its water from reservoirs and lakes in that region since 1842. The city’s growing population sent it to the Catskills for more water, first from the Esopus Creek, which was impounded to create the Ashokan Reservoir in Ulster County.

The Ashokan was constructed under the auspices of the New York City Board of Water Supply (BWS) between 1907 and 1915. Its Olive Bridge Dam and various weirs and dikes backed up Esopus waters for 12 miles, necessitating the removal of homes, farms, businesses, churches, schools, and other structures throughout the valley. Two thousand residents were displaced as four hamlets were flooded and eight others were relocated.

The BWS next turned to the Schoharie Creek, building a dam at Gilboa to create the Schoharie Reservoir. This reservoir, built between 1919 and 1927, forced the removal of 350 residents of the community of Gilboa and neighboring valley lands.

Water from the Schoharie is sent down the Shandaken Tunnel, an 18 mile-long conduit which leads to the Esopus Creek and then runs eastward into the Ashokan Reservoir. The blended waters reach the city’s distribution system through the 92 mile-long Catskill Aqueduct which consists of deep-rock tunnels, steel pipe siphons and buried conduits snaking beneath mountains, valleys and rivers. The aqueduct burrows 1,114 feet beneath the Hudson River between Storm King and Breakneck Mountains near Cornwall.

No sooner had the Schoharie Reservoir been completed then the BWS began development of the Delaware River and its tributaries. Receiving state approval in 1928, the city’s plans to build five more reservoirs were held up by challenges from New Jersey and Pennsylvania, which shared the interstate waters of the Delaware. The dispute went all the way to the U. S. Supreme Court, which in 1931 allowed New York City to take up to 440 million gallons of water a day from the river system. That required the city to scale back its plans to just three reservoirs – one on the Rondout Creek (actually a tributary of the Hudson River); another on the Neversink River; and a third on the East Branch of the Delaware.

The Rondout Reservoir straddling the Ulster and Sullivan County line was built between 1937 and 1954 (it was first placed in service in 1951). The Neversink Reservoir a few miles distant in Sullivan County was constructed between 1941 and 1953 (in service in 1950). Both projects were virtually shut down during World War II, but resumed in 1946.

The communities of Eureka, Montela and Lackawack were eliminated to make way for the Rondout; the hamlets of Neversink and Bittersweet were lost to the Neversink Reservoir. More than 1,500 people were forced to vacate their homes, farms, and businesses in both valleys.

The Pepacton Reservoir on the East Branch in Delaware County was built between 1947 and 1954. The 2,400 foot-long dam at Downsville impounds the largest of the city’s reservoirs. Eighteen miles long, it covers nine square miles, has a 55 mile shoreline and a capacity of 140 billion gallons.

The Pepacton flooded four communities — Arena, Pepacton, Shavertown and Union Grove – displacing 974 people. The city acquired more than 13,000 acres, including cemeteries from which 2,371 bodies were removed to be re-interred elsewhere.

Faced with growing water demand, the city then proposed yet another reservoir on the West Branch of the Delaware River, a plan that prompted a second Supreme Court battle. The court, in 1954, allowed the city to take additional water from the Delaware River system, and the BWS immediately began building the last of its reservoirs, the Cannonsville, in Delaware County.

Constructed from 1955 to 1967, the Cannonsville Reservoir was first placed in service in 1965. The Stilesville Dam impounds 95 billion gallons of water in a reservoir that is 16 miles long. Five more communities were condemned to make way for this reservoir: Beerston, Cannonsville, Rock Rift, Rock Royal, and Granton. Another 941 people were forced to move.

Water from the Pepacton, Neversink and Cannonsville Reservoirs is sent to the Rondout Reservoir by gravity via the 25 mile-long East Delaware Tunnel, the 44-mile West Delaware Tunnel and the Neversink Tunnel, which is six miles long. The combined waters are then sent to the city in the world’s longest continuous underground tunnel, the Delaware Aqueduct, which extends 85 miles from the Rondout Reservoir to Hillview Reservoir in Yonkers. The aqueduct, 1,550 feet below ground at one point, runs 600 feet beneath the Hudson River at Chelsea.

For more information on the city’s water system, which includes 19 reservoirs and controlled lakes in seven counties east and west of the Hudson River, visit the NYC Department of Environmental Protection’s web site.