The Catskill Aqueduct, part of the New York City water supply system, brings water from the Catskill Mountains to Yonkers where it connects to other parts of the sytem. It begins at the Ashokan Reservoir in Olivebridge, New York, in Ulster County. It then heads south, flowing toward Orange County, New York, and then crosses underneath the Hudson River to Putnam County, New York. The aqueduct transports water from Ashokan as well as the Schoharie Reservoir, which feeds into Ashokan. From the Ashokan, the aqueduct traverses in a southeasterly direction through Ulster, Orange, and Putnam, counties. It crosses below the Hudson River bed at Storm King Mountain in Orange county. It crosses into Putnam county on the east side of the river at Breakneck Mountain.

The aqueduct then enters Westchester County, New York, and flows to the Kensico Reservoir, which also receives water from the City's Delaware Aqueduct. It continues from the Kensico reservoir and terminates at the Hillview Reservoir in Yonkers. The Hillview Reservoir then feeds City Tunnels 1 and 2, which bring water to New York City. If necessary, water can be made to bypass both reservoirs.

Construction commenced in 1907. The aqueduct proper was completed in 1916 and the entire Catskill Aqueduct system including three dams, and 67 shafts was completed in 1924.The total cost of the aqueduct system was $177 million.

The aqueduct consists of of cut and cover aqueduct, over of grade tunnel, of pressure tunnel, six miles (10 km) of steel siphon, and of conduit. The 67 shafts sunk for various purposes vary in depth from 174 to . Water flows by gravity through the aqueduct at a rate of about .

The Catskill Aqueduct has an operational capacity of about 550 million gallons per day north of the Kensico Reservoir in Valhalla, New York. Capacity in the section of the aqueduct south of Kensico Reservoir to the Hillview Reservoir in Yonkers, New York is 880 million gallons per day. The aqueduct normally operates well below capacity with daily averages around 350 - 400 million gallons of water per day.

Trivia

• About 40% of New York City's water supply flows through the Catskill Aqueduct.

References

See also

• Delaware Aqueduct
• New York City Water Supply System
• Frank E. Winsor the engineer in charge of construction of of the Aqueduct.