Wusanto Reservoir

Wusanto Reservoir 烏山頭水庫
Wushantou Dam (also known as Coral Lake), Tainan. This photo was taken from airplane window.
Location of Wusanto Reservoir 烏山頭水庫 in Taiwan
Country	Taiwan
Location	Liujia, Guantian Districts, Tainan
Coordinates	23°12′20.5″N 120°23′24.88″E / 23.205694°N 120.3902444°E / 23.205694; 120.3902444Coordinates: 23°12′20.5″N 120°23′24.88″E / 23.205694°N 120.3902444°E / 23.205694; 120.3902444
Status	In use
Construction began	1920
Opening date	1930
Dam and spillways
Type of dam	Embankment Dam
Impounds	Guantian Creek、Zengwun River （by tunnel）
Height	56 m (184 ft)
Length	1,273 m (4,177 ft)
Spillways	Guantian Creek
Spillway type	Gated overflow, service
Spillway capacity	1,500 m3/s (53,000 cu ft/s)
Reservoir
Creates	Wusanto Reservoir
Total capacity	154,158,000 m3 (5.4440×109 cu ft)
Catchment area	58 km2 (22 sq mi)
Surface area	13 km2 (3,200 acres)
Power station
Installed capacity	50 MW
Annual generation	438,000 KWh

Wusanto Reservoir (Chinese: 烏山頭水庫; pinyin: Wūshāntóu Shuǐkù), sometimes spelled Wushanto or Wushantou, is a reservoir and scenic area located in Tainan, Taiwan. It is also referred to as Coral Lake due to its zigzagging shoreline. The reservoir was designed by engineer Yoichi Hatta and was the largest in Asia at the time of its completion in 1930.

Construction of the Wusanto Reservoir began in 1920 and was completed in 1930, with the project financed by the Japanese colonial government. The goal of the project was to provide irrigation for over 100-thousand hectares of farmland in the Chianan area. After construction of the reservoir, the irrigation plain became an important producer of rice for consumption in Taiwan and Japan, with three rice harvests possible each year.

The reservoir was built in conjunction with the Chianan Canal, also designed by Hatta. At the time of its completion, Wusanto Reservoir was the largest reservoir in Asia and the third largest in the world. Construction of the reservoir and of the Wusanto Dam used an uncommon semi-hydraulic fill technique, where fine-grained material is placed at the end of an embankment and then washed into its desired position using jets of water; this is a variant of the hydraulic fill technique. Wusanto Reservoir is the only project constructed with the semi-hydraulic fill technique that is still in use anywhere in the world. This process was expensive and time-consuming, but produced a dam which has proven resistant to Taiwan's severe seismic activity.

Today, the Wusanto Reservoir Scenic Area is a popular tourist destination in Tainan. The area includes a memorial and museum for Yoichi Hatta, as well as a replica of the Temple of Heaven in Beijing. Cherry blossom viewing is a popular event in spring. The area is also known for its abundant native flora and fauna.