Sudbury Reservoir

Sudbury Reservoir
Massachusetts State Park
Metropolitan Water District system, 1910
Country	United States
State	Massachusetts
Counties	Middlesex, Worcester
Towns	Framingham, Marlborough, Southborough, Westborough
Elevation	249 ft (76 m)
Coordinates	42°19′21″N 71°30′45″W / 42.32250°N 71.51250°W / 42.32250; -71.51250Coordinates: 42°19′21″N 71°30′45″W / 42.32250°N 71.51250°W / 42.32250; -71.51250
Area	4,943 acres (2,000 ha)
Dug	1894-1898
Management	Massachusetts Department of Conservation and Recreation
Location in Massachusetts
Website: Sudbury Reservoir

The Sudbury Reservoir (2.02 square miles) is an emergency backup Boston metropolitan water reservoir located in Framingham, Marlborough, Southborough, and Westborough, Massachusetts. Nearly 5,000 acres (2,000 ha) in the Sudbury Reservoir watershed are administered by the Massachusetts Department of Conservation and Recreation as a limited-access public recreation area.

The reservoir was first begun in 1878, as part of a system of reservoirs fed from the Sudbury River to supplement the Lake Cochituate system in Natick. Today's reservoir was created by excavation from 1894-1898, with construction undertaken in sections. It was begun by the City of Boston but completed by the newly formed Metropolitan Water Board (predecessor to the modern Massachusetts Water Resources Authority). All told, construction required moving about 4.5 million cubic yards of soil and boulders. Water began to fill the reservoir on February 8, 1897, with construction of the reservoir's new Sudbury Dam on the Stony Brook Branch of the Sudbury River completed later that year.

When completed, the reservoir's surface area was 2.02 square miles (5.2 km²), its average depth was 17 feet (5.2 m) and maximum depth was 65 feet (20 m), and its capacity was 7.253 billion US gallons (27,460,000 m³). The reservoir was fed from the Wachusett Reservoir on the west by the Wachusett Aqueduct (1898), and by local streams. To improve the water quality of the local streams, filter beds were constructed adjacent to the reservoir. The reservoir's water was delivered to the Weston Reservoir to the east by the Weston Aqueduct (1901), or via a channel to the Framingham reservoirs and the Sudbury Aqueduct to the Chestnut Hill Reservoir.