The construction of Shihmen Reservoir started in July 1954 and it was completed in June 1964. Spending almost NT$ 3,200 million, it took 8 years to construct the reservoir and more than 7000 people participating in the project. Shihmen Reservoir features power generation, public water supply, irrigation, flood control, and tourism. In addition to Shihmen Dam, there are many important facilities like spillway, drainage tunnel, Shihmen Power Plant, desilting tunnel, multilevel intake, afterbay and Houchi Weir, Shihmen Cannel, Taoyuan Cannel and Zhongzhuang Auxiliary Reservoir in downstream.
Shihmen Reservoir, where the entire area is between Daxi District, Longtan District, and Fuxing District in Taoyuan City, crosses the Dahan River which is the main tributary of Tamshui River.
Although the original goal of building Shihmen Reservoir is for irrigation and flood control, public water supply is the main function for these years. The reservoir supplies the water to New Taipei City, Taoyuan City, and Hukou Township in Hsinchu County. The average daily water supply is almost 80,000m3 including water supply to Ban-Xin water purification plant through Yuanshan Weir in downstream, Shihmen and other water purification plants through the Shihmen Cannel in upstream and Danan water purification plant through Taoyuan Cannel near the Houchi Weir.
Since Shihmen Reservoir was completed and operated, the reservoir has made a great contribution to the improvement of agricultural production in northwest Taiwan, development of industry and commerce, improvement of people’s living standards, and prevention of flood and drought.
1. Irrigation: area 36,500 hectares passing through Taoyuan and Shihmen Canal.
2. Water Supply: 800,000m3/day to New Taipei city, Taoyuan city, and Hukou township in Hsinchu county
3. Power Generation: 230,000,000kWh/year
4. Flood control
1. Type: A rolled earth fill dam of center impermeable core type
2. Dam Height: 133.1m
3. Dam Length: 360m
1. Spillway: 6 arched-controlled-floodgate, Maximum flow rate is 11400m3/sec.
2. Drainage Tunnel: 2 tunnels. designed flow rate is 1,200m3/sec for each one.
3. Desilting Tunnel: reconstructed from power generation tube, Maximum flow rate is 300m3/sec and the desilting efficacy is almost 1,000,000m3 sediments/year.
4. Permanent River Outlet: designed flow rate is 34 m3/sec.
5. Multilevel intake: there are three level intakes. Designed flow rate is 16.2 m3/sec for each one.
6. Shihmen Canal: designed flow rate is 18.4 m3/sec.
7. Taoyuan Canal: designed flow rate is 16.8 m3/sec.