Shihmen Dam

Shihmen Dam
View from below the dam, showing the main rock fill dam (right) and the spillway.
Official name	石門水庫
Location	Fuxing, Taoyuan City, Taiwan
Coordinates	24°48′38″N 121°14′39″E / 24.81056°N 121.24417°E / 24.81056; 121.24417
Construction began	July 1955; 69 years ago (1955-07)
Opening date	June 14, 1964; 60 years ago (1964-06-14)
Construction cost	NT$1.4 billion
Owner(s)	Taiwan Water Resources Agency
Dam and spillways
Type of dam	Rolled rockfill
Impounds	Dahan River
Height	133.1 m (437 ft)[1]
Length	360 m (1,180 ft)[1]
Spillway type	Gated overflow
Spillway capacity	11,400 m3/s (400,000 cu ft/s)[2]
Reservoir
Creates	Shihmen Reservoir
Total capacity	309,120,000 m3 (250,610 acre⋅ft) (nominal) 251,880,000 m3 (204,200 acre⋅ft) (1997)[1]
Catchment area	763.4 km2 (294.8 sq mi)[1]
Surface area	8.0 km2 (2,000 acres)[1]
Power Station
Turbines	2x 45 MW[3]
Installed capacity	90 MW[3]
Annual generation	200 million KWh[4]

Shihmen Dam (Chinese: 石門水庫; lit. 'Stone Gate Dam'; also spelled Shimen or Shihman) is a major rock fill dam across the Dahan River in northern Taoyuan City. It forms the Shihmen Reservoir (石門水庫), Taiwan's third largest reservoir or artificial lake. It provides irrigation in Taoyuan, flood control for the Taipei Basin, and hydroelectricity and domestic water supply for more than three million people in northern Taiwan.

Completed in 1964 after nine years of construction, Shihmen was Taiwan's first multi-purpose water project and a major step towards the island's economic independence after World War II. Year-round water releases from the dam enabled additional rice harvests and doubled Taoyuan's annual agricultural output, while the reservoir became a tourist destination due to its scenery and plentiful fisheries.^{[citation needed]} However, the project was criticized for its high cost and its impact on local communities, as more than 2,000 people were displaced to make way for the reservoir.

Like some other reservoirs in Taiwan, Shihmen has suffered from sedimentation, reducing its capacity by over a third. Efforts to reduce the rate of sediment accumulation, including dredging, check dam construction and watershed restoration work, have had a limited effect. This has diminished both the Shihmen Dam's capability to contain floods and provide water during droughts.