Quabbin Aqueduct

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**Quabbin Aqueduct**
Geographical Data
Quabbin Aqueduct shaft two in South Barre
Official name	Quabbin Aqueduct
Begins	Quabbin Reservoir
Ends	Wachusett Reservoir
Maintained by	MWRA
Length	24.6 mi (39.58 km)
Conduit height	12.75 ft (3.89 m)
Conduit width	11 ft (3.35 m)
Capacity	400 ft³/s (11.33 m³/s)
Construction began	1897
Opening date	1905
Coordinates	42°23′12″N, 71°48′08″W

The Quabbin Aqueduct carries water from the Quabbin Reservoir to the Wachusett Reservoir. It is part of the Eastern Massachusetts public water supply system, maintained by the Massachusetts Water Resources Authority (MWRA). It is one of the longest tunnels in the world being 1/2 mile (0.80 km) shorter than the Hetch Hetchy Aqueduct.

[edit] Physical Characteristics

Water from the 412 billion gallon capacity Quabbin Reservoir flows through the Quabbin Aqueduct from the Northeast side of the Quabbin, up a grade to the Ware River Diversion in South Barre, Massachusetts, and then down grade to the Wachusett Reservoir through a power station near the Oakdale section of West Boylston, Massachusetts. This flow occurs by natural siphon action, the high point in the siphon being at the Ware River Diversion. The water surface at the Quabbin Reservoir is about 530 feet (161.54 m) above mean sea level (MSL). The water surface at the Wachusett Reservoir is about 384 ft (117.04 m) MSL, and the water surface at the Ware River Diversion is about 660 ft (201.16 m) MSL.

[edit] Novelty

A natural siphon can only lift water about 30 feet (9.14 m), so the aqueduct is several hundred feet underground in several places so that the water head is only about 25 feet (7.62 m) within the suction side of the aqueduct. Portions of the aqueduct follow the route of the Ware River Railway that discontinued with the building of the Quabbin Reservoir. The siphon starts at the Ware River Diversion by feeding the river water into the aqueduct. If the aqueduct branch that goes to the Wachusett Reservoir is closed (the Wachusett-Coldbrook branch), the Ware River water feeds the Quabbin Reservoir for storage. If the Wachusett branch is open, the water flows in both directions. Once the Wachusett branch begins to create sufficient suction as it fills, the Ware River Diversion inlet is closed and the water flow from the Quabbin to the Wachusett Reservoirs continues as a natural siphon.