Accession Number:

ADA143516

Title:

National Program for Inspection of Non-Federal Dams. Mechanicsville Dam (CT 00182), Thames River Basin, Thompson, Connecticut. Phase I Inspection Report.

Descriptive Note:

Corporate Author:

CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV

Personal Author(s):

Report Date:

1979-09-01

Pagination or Media Count:

84.0

Abstract:

Mechanicsville Dam is a composite masonry and earth dam consisting of a stepped stone masonry overflow section surmounted by a concrete superstructure forming 16 spillway bays, an earth dike on the right abutment, and a stone wall and abandoned power house on the left abutment. The entire length of the dam is about 568 ft. It is a run-of-the river dam which once served the power needs of a downstream industrial complex. The only purpose of the dam now is to pond water for a dry hydrant located in Mechanicsville. The reservoir is about 8,000 ft. long and has a surface area at spillway level of about 44 acres. The drainage area above the dam is about 112 sq. mi. and the maximum storage to the top of dam is estimated at about 900 acre-ft. The height of the dam is 21.75 ft. The dam is judged to be in generally fair condition. There is no low level dewatering facility. The piers of the concrete spillway bridge are badly eroded and the right abutment dike is covered with tree and brush growth. There is a gap in the left abutment stone wall about 8 ft. wide. The abandoned power house is in disrepair and the dam shows no sign of having received any maintenance in recent years. There is a low-lying boggy zone about 300 ft. below the dike. The test flood outflow would overtop the left abutment wall by about 5.5 ft. and the right abutment dike by about 2.8 ft. The spillway can pass 10,200 cfs or about 33 percent of the test flood outflow without overtopping the left abutment.

Subject Categories:

  • Hydrology, Limnology and Potamology
  • Civil Engineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE