The torrential rain brought by Typhoon Morakot, which killed hundreds and left hundreds missing, exposed crucial questions about environmental policies, flood control strategies and water resources management, experts said yesterday.
Flooding is a long-standing problem that endangers thousands during typhoon season.
The government has spent more than NT$500 billion (US$15.23 billion) on disaster prevention and construction of water conservancy infrastructure in the past 40 years, said Flood Management Watch, an alliance of civil environmental groups.
The country remains highly vulnerable to flooding despite the NT$116 billion, Flood-Prone Area Management plan for 2006 to 2013.
The plan is also known as the “Eight-year, NT$80 billion” project, referring to the funding to improve rivers by the Water Resources Agency (WRA).
“We will only get into deeper water if we continue to stick with the traditional construction methods of flood control,” said Lin Sheng-feng (林盛豐), an associate professor of architecture at Shih Chien University, who served as minister without portfolio in the Democratic Progressive Party (DPP) government.
“Dramatic climate change will bring droughts and floods. When floods come, it is on a scale that levee structures can’t withstand, no matter how high their prevention standards,” Lin said.
The dikes along tributaries of rivers are built to cope with once every 50-year flood events, while the standard embankment dams along main streams are built to withstand 100-year floods.
Last year, the country saw a once-in-200-year flood following Typhoon Kalmaegi, while the flooding caused by Morakot was close to a recurrence interval of 250 years, the Central Weather Bureau said.
Enacting legislation to restrict land use and reverse overdeveloped regions to environmentally healthier lands was crucial, Lin said.
The former DPP government proposed a draft restoration homeland act in December 2005, but the bill was never put onto the legislative agenda because of a Chinese Nationalist Party (KMT) boycott.
“The main principle in the draft was that ‘human beings cannot conquer nature,’” Lin said.
“In the past when the rainfall was small, humans used construction methods to overcome everything. Now, torrential rain has become part of our life,” Lin said.
“We have to acknowledge this fact and avoid disasters,” he said.
Lin said he met strong opposition when he tried to put the idea into action when he was in government.
“On several occasions after landslides and debris flows, we came up against a brick wall when we tried to convince residents not to rebuild roads in high-altitude areas,” he said.
Hsu Chan-shuan (徐嬋娟), who leads Flood Management Watch, which monitors the implementation of the “Eight-year, NT$80 billion project,” said the program should be suspended.
“The government’s flood prevention system needs an overhaul because it uses the wrong approach of building up embankments and the like to prevent floods,” Hsu said.
The flooding brought by Morakot destroyed the embankments of the Laonong River (荖濃溪) in Kaohsiung County, the Taimali River (太麻里溪) in Taitung County, the Dajia river (大甲溪) in Taichung County and Niouchou River (牛稠溪) in Chiayi County, among others.
Destruction of river works has not only raised doubts about the effectiveness of such flood control measures, but also worsened the flooding. When dam failures occur, they create a total inundation as opposed to the gradual inundation caused by rainfall.