Hibbs Island in Norris, Tennessee is located on the Clinch River at Mile 77.9, about 1 mile downstream from Norris Dam, which is owned by the Tennessee Valley Authority. Norris Dam impounds water for a 110MW hydroelectric powerhouse that was completed in 1936. The island, which belongs to TVA as part of Norris Reservation, connects the two sections of the Norris reregulating weir, a low dam built to regulate the release flow from Norris Dam. The main purpose of the weir is to regulate water flow during off-generation periods from Norris Dam through a series of low-level pipes that ensure a constant minimum flow downstream. This minimum flow is paramount for the local fishing attraction, and the weir function is a design parameter in the flow rates that helps control flooding and promote public safety.
Mesa conducted an evaluation of Hibbs Island in 2020 to create a solution regarding the current deterioration of the island and its impact on the reregulating weir stability.