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Dam and Tunnel Construction

The Delaware Aqueduct stretches over 85 miles between the Rondout Reservoir and Yonkers, where it was connected to an existing water supply system. It is the longest tunnel in the world! The first water diversion for New York City was the Croton Aqueduct constructed between 1837 and 1842. The Croton Reservoir stood at 40-42nd Streets at site of the current New York Public Library. Today the Croton System delivers only10% of NYC water; the Catskill System 40%; and, the Delaware System 50%.

The Rondout Reservoir is eight miles long, 180 feet deep and contains over fifty billion gallons of water. It contains water from the Rondout Creek and also brings water from the East Delaware and Neversink Reservoirs, located to the northwest. The reservoir supplys over one billion gallons of pure water to New York City daily. Thaddeus Merriman, Chief Engineer of the Board of Water Supply in 1928, drew up the original plans for the dam. When he died in 1939, the Board named the dam after him.