The Janghua Dam is located in Fusing, a city in Taoyuan County on the island of Taiwan. Taoyuan is a northern county, but situated 40 kilometers (24 miles) south of Taipei, the nation's capital.
The dam serves the Tahan River, which translators sometimes render into English as the Dahan River. This river is a tributary of Taiwain's Danshui River. The dam itself is often called the Junghua Dam or the Jhonghua Dam. The alternate spellings indicate the fact that Chinese sounds do not perfectly match English ones.
Construction on the Janghua Dam first began in December, 1978. Since work was completed by June, 1984, the construction of the dam took less than six years to complete. The total cost of the dam was $1.83 billion in New Taiwan dollars.
As of the time of publication, one New Taiwan dollar is worth approximately 3.4 cents, meaning that the Janghua Dam cost about $640 million to construct.
The Janghua Dam is as one of two dams on the Tahan River; the Shihmen Dam is located about 27 kilometers farther downstream. The main purpose of the Janghua Dam is to prevent river sediments, such as gravel and sand, from continuing downstream to the Shihmen Dam. Without the Janghua Dam to prevent this, the Shihmen Dam could clog with silt and perform less efficiently.
Most dams create a sizable reservoir behind them, but the Janghua Dam is an exception. The reservoir behind the Janghua Dam has been almost entirely filled in with sediments, which leaves it with virtually no storage capacity. This circumstance is a result of the dam's intended purpose; its main function is to prevent excess silt from reaching the Shihmen Dam father downstream on the Tahan River.
However, the Janghua Dam also performs a secondary function: it creates a water head high enough that the generation of hydro-electric power becomes feasible. At Yising, 6 km. downstream from the Janghua Dam, there is an electric plant capable of generating 200 million units of power per year. The Shihmen Dam generates an equal amount of electricity annually; this addition generation is possible because of the Janghua Dam's essential anti-silting function that benefits facilities downstream.
