Tue, Oct 05, 2004 page2

• Rebuilt plant will be floodproof

  A CHANGED RIVER It will take three years to resume Taipower's operations on the Tachia River, but experts say they've gotten wiser to the area's hazards

  • By Chiu Yu-Tzu / STAFF REPORTER
  • • 
    • 
    • 

  Natural disasters forced Taiwan Power Company official Chen Chia-nan (陳嘉南), who has spent three decades at the Tachia River hydroelectric plant, to rethink the siting of such facilities.

  The Wanjung Hydroelectric Project's director in Kukuan, Tai-chung County, is shepherding a NT$8.4 billion project to revamp the plant in light of the 921 Earthquake and subsequent flooding and landslides.

  

  Taipower plans to repair the Kukuan hydroelectric plant, damaged by flooding and deposits of eroded materials, by summer 2007.

  PHOTO: CHIU YU-TZU, TAIPEI TIMES

  "We are building new facilities in much higher places where they cannot be inundated when flooding occurs," Chen said.

  

  Huge deposits of debris from eroded mountain slopes and landslides have changed the Tachia River's course.

  PHOTO: CHIU YU-TZU, TAIPEI TIMES

  The 124km-long Tachia River originates on the 3,742m-high Nanhu Mountain, the highest peak in the northern Central Mountain Range. Its rapid 1,200m drop over a 70km section between Tehchi and Shihkang makes the river a perfect site for generating hydroelectricity. As early as 1922, the Japanese built a first plant there.

  The current Kukuan plant began operating in 1961, and convenient roads brought several hot spring hotels to the area. But the 921 Earthquake and heavy rains between March and June 2000 deposited sand, stones, driftwood and other debris on the riverbed, raising it by 10m. And on July 30, 2001, heavy rains brought by Typhoon Toraji raised the riverbed by another 9m, inundating the plant's underground control room.

  "The river's surface reached the exit of the plant's water tunnel, eventually causing it to malfunction," Chen said.

  The troubles continued this year as six state-run power plants along Tachia River were inundated and damaged by floodwaters from Tropical Storm Mindulle in early July.

  "At our site, there was once a suspension bridge, which was 22m higher than the surface of the river. When Mindulle came, the river's surface was 4m higher than the bridge, which was eventually washed away," said Tsai Chin-fa (蔡進發), chief of the Wanjung Project Office's No. 3 inspection team.

  He said the new water tunnel cannot be inundated because its exit is at a reservoir operated by Taipower.

  In the meantime, Taipower must spend NT$1 billion annually to boost power generation at other plants to make up for the Tachia plant.

  The plant's planned reopening in the summer of 2007 will not only aid Taipower but should also help revive the area around Kukuan. Since the 921 Earthquake, the area has suffered from frequent road blockages after heavy rain.

  "It's not necessary to be pessimistic about the future of Tachia River because people can always find a way out," Taipower vice president Tsai Ying-chau (蔡英久) said.

  He said that several small generators along the river had been buried by mud-slides decades ago, but that engineers will build new plants in more appropriate places.

  "To make peace with nature, we also adopted ecological engineering methods to fortify the unstable slopes nearby. Recent heavy rains did not trigger mudflows or landslides" in those areas, Tsai said.

  Kukuan residents hope the government will restore not only power plants but also collapsed roads between Kukuan and Techi, which have been closed since the 921 Earthquake.

  "We've lived on tourism for years. The tourism industry will never be revived without solving traffic problems and reopening the Central Cross-Island Highway," said Henry Chang (張明仁), general manager of the Dragon Valley Hotel in Kukuan.

  Roads to a popular national forest recreation area at Pahsien Mountain, where the Shihwen and Chiapao rivers meet, have been closed since July.

  However, the highway's possible reopening has been a controversial issue for years. Environmentalists have called on the government to leave the damaged mountain areas alone, while the government spent billions to repair roads and restore damaged sites. This summer's floods undid much of the road repair work.

  Chung Ting-maw (鐘丁茂), an ecologist at Providence University in Taichung, and his research team examined several reconstructed sites on slopes and mountaintops in disaster areas and found that some could not withstand this summer's abnormally heavy rains.

  "If the government doesn't give up highway reconstruction work, it should inform residents of the risks they face living in fragile, water-logged mountainous areas," Chung said.

  Jack Cheng (鄭皆達), a National Chung Hsing University soil and water conservation expert, said nature and construction can be reconciled by environmentally friendly engineering methods.

  "Silt and stones piled up in these Tachia River tributaries must be removed to make the riverbed deeper and the watercourse wider," said Cheng, who has researched the area's mountains for years.

  Public Construction Commission vice chairman Kuo Ching-chiang (郭清江) made similar suggestions.

  "The mountains' geological structure became quite unstable and there's not enough room for the riverwater to flow. If we don't do anything to remove the factors causing the danger, mudflows and landslides will continue to cause tragedies," Kuo said.
• Most Popular

  • 1

    Chinese technicians join airport MRT project

  • 2

    A train for whom? Is a new monorail helpful for Cairo?

  • 3

    Apple is giving Intel’s turnaround some momentum

  • 4

    Taiwan firms eye Philippines amid shift to non-China supply chains: CIER

  • 5

    Kinmen probes potential Chinese sex spy