Duncan is a local government-owned earth dam located in Fayette, Tennessee, near Liberty Hill, along the Muddy Creek. Built in 1960, this structure stands at a hydraulic height of 15 feet and a structural height of 20 feet, with a length of 270 feet. With a storage capacity of 56 acre-feet, Duncan serves a primary purpose that remains unspecified. The dam has a low hazard potential and is currently in a condition that has not been rated.

Despite its age, Duncan has been regularly inspected, with the last inspection conducted in April 2020. The dam is categorized as having a moderate risk level (3), prompting the need for ongoing risk management measures to ensure its safety and stability. While the dam does not have a regulated state jurisdiction or permitting, it remains an essential water resource structure within the area, contributing to the local water management system. With its uncontrolled spillway and lack of outlet gates, Duncan plays a crucial role in managing water flow and storage for the surrounding area.