The reservoir provides drinking water for Willimantic and helps control flooding in the 159-square-mile Thames River watershed.

[5] Designed and constructed by the United States Army Corps of Engineers, the dam substantially reduces flooding along the Quinebaug, Shetucket, and Thames rivers.

The flood storage area for the entire project covers about 1,880 acres (7.6 km2) in the towns of Mansfield, Windham, and Chaplin, Connecticut.

The park offers boating (8 mph limit), fishing, a shaded picnic area and many miles of hiking, mountain biking and cross-country ski trails.

A boat launch is located on Bassetts Bridge Road in the town of Mansfield, 1/2 mile east of the state park entrance.