Wushantou Dam

Wushantou Dam is an embankment dam in Guantian District, Tainan, Taiwan. The dam was designed by Yoichi Hatta and built between 1920 and 1930 during Japanese rule to provide irrigation water for the Chianan Plain as part of the Chianan Irrigation system. Because the natural flow of the Guantian River and other local streams was insufficient for irrigation of a planned 100000 ha, a tunnel was constructed to divert water from the Zengwen River to fill the reservoir. In 1974, the Zengwen Dam was completed on the Zengwen River shortly above the diversion tunnel, stabilizing and reducing the sediment load of water flowing into Wushantou Reservoir.



The dam consists of a curved embankment 50.5 m high and 1273 m long, containing 5400000 m3 of material. The reservoir comprises 9 km2 and was designed to store 154160 dam3 of water. However, as of 1990 it had been reduced to 83759 dam3 due to severe erosion problems upstream. A concrete overflow spillway is located shortly to the south of the dam, providing a maximum outflow of 1500 m3/s. The dam sits at the head of a 58 km2 catchment area, which increases to 539 km2 when including the portion of the Zengwen River watershed diverted into the reservoir.