Catskill Aqueduct

History

Construction began in 1907. Numerous test shafts were dug to determine the stability of the area's sub-surface geology to ensure both the impermeability of the completed reservoirs and holding strength of their various levees, tunnels, dikes, and dams, and the integrity of the structures of the aqueduct. 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 constructing the system, less interest on the bonds to finance it, was $177 million ($ in ).

Specifications

The 92 mi aqueduct consists of 55 mi of cut and cover aqueduct, over 14 mi of grade tunnel, 17 mi of pressure tunnel, and 9 mi of steel siphon. The 67 shafts sunk for various purposes on the aqueduct and City Tunnel vary in depth from 174 to. Water flows by gravity through the aqueduct at a rate of about 4 ft/s.

The Catskill Aqueduct has an operational capacity of about 550 e6USgal 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 e6USgal per day. The aqueduct normally operates well below capacity with daily averages around 350 - of water per day. About 40% of New York City's water supply flows through the Catskill Aqueduct.

Geography

The Catskill Aqueduct begins at the Ashokan Reservoir in Olivebridge, New York, located in Ulster County, which is fed by its own watershed and flow from the upstream Schoharie Reservoir. The aqueduct traverses in a southeasterly direction, first tunneling beneath the Rondout Valley and Rondout Creek in the town of Marbletown, then beneath the Wallkill River in the town of Gardiner in Ulster County before flowing toward Orange County. At Storm King Mountain it crosses 1100 ft below the Hudson River to Breakneck Mountain in Putnam County on the east side of the river.

The aqueduct then enters Westchester County, and flows to the Kensico Reservoir, where it joins with waters of the Kensico drainage basin and the city's Delaware Aqueduct. It continues from Kensico 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.

References

References

1. [https://archive.org/details/cassiersmagaz401911newy/page/259/mode/1up?view=theater The Catskill Aqueduct], ''Cassier's Magazine - An Engineering Monthly'', Volume XL, May-October 1911, pp. 252-272, 323-344, 437-461
2. [http://www.dukelabs.com/ForTeachers/NYC_Water_Supply/NYCWaterSupply.htm A history of the NYC water supply system - Merguerian, 2000c]
3. [https://books.google.com/books?id=s2MEAAAAMAAJ&dq=bryn+mawr+siphon&pg=PA23 Catskill Water Supply: A General Description and Brief History]
4. Kevin Bone, ed. Water-Works: The Architecture and Engineering of the New York City Water Supply (New York: Monacelli, 2006), 258.
5. [http://www.greatachievements.org/?id=3610 Water Supply and Distribution Timeline – Greatest Engineering Achievements of the Twentieth Century]
6. [http://www.eserc.stonybrook.edu/cen514/info/NYC/WaterSupply.html New York City water supply system] {{webarchive. link. (2007-05-21)
7. [https://books.google.com/books?id=KIkHuzvZTGYC&dq=catskill+aqueduct+hudson+river+crossing&pg=RA1-PA190 The Hudson River Guidebook By Arthur G. Adams]