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Tully Lake Flood Risk Management Project

Click for hi-resolution photo of Tully Lake dam

Tully Lake is located on the East Branch of the Tully River in Royalston, Mass., and is a part of a network of flood risk management dams on tributaries of the Connecticut River (including sister dam Birch Hill Dam). The dam at Tully Lake in Royalston lies across the East Branch of the Tully River. From Athol, it can be reached traveling three miles north on Route 32.

In conjunction with Birch Hill Dam, Tully Lake provides flood protection to Athol, Orange, and other communities on the Millers River. Tully Lake also helps to reduce damages along the main stem of the Connecticut River.

Construction of the dam was initiated in March 1947 and completed in September 1949. Routes 32 and a power transmission line were relocated. The cost of the project was $1.7 million. The project consists of an earthfill dam with stone slope protection 1,570-feet long and 62-feet high; a gated concrete circular tunnel 274-feet long with a diameter of six feet; and a concrete chute spillway cut in rock with a 255-foot concrete weir. The weir’s crest elevation is 16 feet lower than the top of the dam. In April 1987, two storms dropped about 6 inches of rain, raising the water level to over 35 feet at the dam, utilizing 62% of the storage capacity. It is estimated that Tully Lake prevented over $3 million in damages to downstream property from this one storm.

The project has prevented $28.1 million in flood damages since it was built (as of September 2011).

Tully Lake contains a recreation pool that fluctuates seasonally. From the spring until the fall, the lake has a maximum depth of 16 feet and covers 300 acres. From fall to spring, the pool is drawn down to a depth of 11 feet. The flood storage area of the project totals 1,130 acres and stretches into Athol. This area is empty most of the time and is utilized only to store floodwaters. The lake and all associated project lands cover 1,263 acres. Tully Lake can store up to 7.17 billion gallons of water for flood control purposes. This is equivalent to 8.3 inches of water covering its drainage area of 50 square miles.

The Reservoir Control Center (RCC), located in Concord, Mass., is the "nerve center" for all Corps-operated dams in New England. Using radio and satellite communications, the team constantly monitors river levels and weather conditions and directs the operation of the dams during high flows.

Nearly 77,000 visitors annually enjoy Tully Lake. For details call (978) 249-9150 or visit

- Updated: May 4, 2021