The Delaware Aqueduct is the newest of the New York City aqueducts. It takes water from the Rondout Reservoir through the Chelsea Pump Station, the West Branch Reservoir, and the Kensico Reservoir, ending at the Hillview Reservoir in Yonkers, New York.
The aqueduct was constructed between 1939 and 1945, and carries approximately half of the New York City water supply of 1.3 billion US gallons (4,900,000 m3) per day. The Delaware Aqueduct leaks up to 36 million US gallons (140,000 m3) per day.
At 85 miles (137 km) long and 13.5 feet (4.1 m) wide, the Delaware Aqueduct is the world's second longest continuous underground tunnel after the Thirlmere Aqueduct in North West England.
Read more about Delaware Aqueduct: Leaks