 The dam — which was renamed for Congressman James Percy Priest (1900–1956) — was completed in 1968.The impoundment of the river forced water to back up through underground channels, leading to the formation of Couchville Lake, the small lake situated near the center of the park.In 1972, the Corps of Engineers leased of land on the east shore of the reservoir to the state of Tennessee for the formation of a state park.