Mansfield Hollow Dam
Posted by: 
NorStar
N 41° 45.392 W 072° 10.861
18T E 734360 N 4626586
The Mansfield Hollow Dam was built as one of six flood control dams in the Thames River watershed, and the impounded water, Mansfield Lake, is used for boating, fishing and other recreational use.
Waymark Code: WM44GG
Location: Connecticut, United States
Date Posted: 07/06/2008
Views: 57
The Mansfield Hollow Dam is one of six dams placed in the Thames River watershed that regulate the water flow to prevent flooding in downstream communities such as Norwich, CT.
The dam is mostly a rolled earth dam, with a reinforced concrete spillway and control center. The dam part is 14,050 feet long and the highest point is 273.0 Ft NGVD (78 ft). The spillway is an Ogee weir with a length of 690 feet and an elevation of 257.0 ft NGVD (62 ft). Five 5' x 7' conduits control the flow of water through the dam.
Today, the state of Connecticut has developed a recreational area that includes picnic areas, camping grounds, swimming areas and boat ramps. Motor boats are allowed.
You can visit the spillway. Don't follow the signs all the way to the state park. From state route 195, about halfway between the intersection with US 6 in Willimantic and Mansfield Center, turn east onto Bassetts Bridge Road (as if you were going to the state park). At about .4 miles, turn south (right) onto Mansfield Hollow Road and follow that road to the end. There is parking within site of the dam. You can walk to the top of the spillway and look across the lake and see much of the earthen impoundment.
You wouldn't know it from the size of the river the day that I visited, but there have been memorable floods in the area and down river. There was resistance in building the dam, but it proved its worth when it held back the rain water from hurricane Diane. A later potential for flooding was averted in the 1980s from snowmelt.
Sources:
(
visit link) - U.S. Army Corps of Engineers web site on the dam.
(
visit link) - Connecticut DEP web site on Mansfield Hollow State Park.