Llyn y Fan Fach Reservoir Dam

The Llyn y Fan Fach Reservoir Dam is a Grade II listed structure, approximately 65 meters long and oriented from west-northwest to east-southeast. It features a concave concrete wall. At the center of the dam, there is a spillway and weir, which has side walls made of quarried rubble stone topped with concrete copings, along with a concrete stream bed. A circular valve tower is built into the rear face of the dam, allowing for water extraction from the reservoir via a siphon. This siphon leads to an outlet tunnel located about 75 meters to the north, which passes under a stone arch with splayed flanking walls. The keystone of the arch is inscribed with the date 1920.