Changing China

Giant on the move

Taiwan’s killer mudslides

September 17, 2009

After Taiwan’s worst storm in 50 years killed hundreds in massive mudslides last month, the government blamed the freak weather while survivors said the government’s slow response after the Aug. 7-9 storm made matters even worse.


Only recently, with reconstruction under way, have officials in the six-county disaster area begun asking what contributing factors may have caused the steep mountainsides to give way, hurling boulders and walls of mud onto riverside villages below. Nearly 770 people are presumed to have died, most of them buried alive.


In the absence of any official declaration of the underlying causes, residents have filled the void with speculation.


Taiwan’s forestry bureau says native subtropical trees had covered most of the deadly mudslide areas of Kaohsiung County in southern Taiwan, doing more to hold mountain sides intact than to loosen them. Villagers had planted mainly bamboo, mangoes, peaches and taro on the lower hillsides. They had shunned betel nut plantations and high-mountain tea, which are common elsewhere on the island and are notorious for destablising soil for lack of deep roots, an agricultural official said.


Later this month, officials will investigate accusations that blasting for a 15-km water diversion tunnel in the worst-hit village caused erosion that made the area susceptible to mudslides, the Government Information Office said. But Taiwan’s water resources chief denied that tunnel construction might have weakened the moutain sides. Other disaster authorities point toward Taiwan’s fragile geology and ecosystem, including repeated earthquakes, typhoons and an early 2009 drought that have left hillsides at increased risk, allowing even huge deep-rooted trees to fall last month.


“Taiwan is an important case study in climate change,” said Chern Jenn-chuan, deputy minister of the cabinet’s Public Construction Commission. “We can say that natural disasters will be more and more severe. We can be sure of that.”


Mountain villagers and land-use experts offer a more ominous theory that could mean disaster for other communities on the steep and populous island during future typhoons, which are common every year from July through October. Their claim: Decades of forestry, farming and over-population have loosened mountain soil all over the island, leaving it prone to massive slides.


Government-sponsored logging through most of the 1900s thinned forests that would otherwise help fortify the soil. Logging is banned today, but the old forests have not grown back to their original scale. The widespread planting of high-elevation farms starting from former strongman Chiang Kai-shek’s era decades ago has further weakened hillsides, especially where villagers rely on crops such as betel nut that do not anchor the soil.


“These are facts. The high mountain topography and climate of Taiwan are unique. You can’t allow high-density farming,” said Alang, an aide to legislator Chen Ying, who represents Taiwan’s numerous mountain-dwelling aboriginals in parliament.


Taiwan’s population of 23 million, the world’s 15th densest, itself has spilled too far into the mountains along with tracts of city-like development rather than the well-spaced, tree-covered homes found at high elevations overseas, said Chen Hung-yu, a geosciences professor at National Taiwan University. “It should be said that the population is too high, that not so many people should be living up there,” he said.


The island government, though hesitant to discuss historical factors behind the mudslides, will limit the width of new roads in disaster-prone areas and urge up to 60 communities of a few dozen to a few thousand households apiece to move to safer ground, Chern said. Officials will also re-examine farming and forestry policies with an eye toward change, he said.


Images from the typhoon disaster area:

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