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Union Village Dam Flood Risk Management Project

Union Village DamUnion Village Dam in Thetford is situated on the Ompompanoosuc River, four miles above its confluence with the Connecticut River and 11 miles north of White River Junction. From White River Junction, the dam can be reached by traveling U.S. Route 5 north to Route 132 west then following signs to the project.

Union Village Dam provides flood protection to the Union Village section of Thetford, Norwich, and the White River Junction and Wilder Village sections of Hartford. It also reduces flood damage in the New Hampshire communities of Hanover and West Lebanon. In conjunction with other Corps dams and reservoirs in the Connecticut River Basin, Union Village Dam reduces flood damages in communities situated downstream on the Connecticut River.

Construction of Union Village Dam began in March 1946 and was completed in June 1950 at a cost of $4.1 million. The project consists of an earthfill dam with stone slope protection 1,100 feet long and 170 feet high; a gated 1,167-foot-long circular concrete conduit with a diameter of 13 feet; and a chute spillway cut in rock with a 388-foot-long concrete ogee weir. The weir’s crest elevation is 20 feet lower than the top of the dam. Approximately two miles of highway were relocated to accommodate the project. The project has prevented $56.6 million in flood damages since it was built (as of September 2011).

There is no lake at Union Village Dam except during the winter, when a 50-acre lake with a depth of 20 feet is maintained to keep the floodgates from freezing. The flood storage area of the project totals 740 acres and extends 3.5 miles upstream. The project and associated lands cover 979 acres. Union Village Dam can store up to 12.4 billion gallons of water for flood control purposes. This is equivalent to 5.65 inches of water covering its drainage area of 126 square miles.

The Reservoir Control Center (RCC) provides information about river flows, dam operations, snow depths, recreational water releases, and more.

For more information, or for recreation opportunities, call (802) 649-1606 or visit the website at:

- Updated: May 4, 2021