Experts urge local geography included in flood control in response to climate change 因應氣候變遷 學者籲治水防災納地質因素

Extreme weather disasters push pundits and officials to reconsider disaster mitigation planning.


Presenter: Central and southern Taiwan got hit with extremely heavy rain in August. Experts say that local geography needs to be considered in flood control and suggest building more retention basins.

Central and southern Taiwan experienced extreme torrential rain earlier in August, causing flash floods and triggering landslides, and destroying bridges. Crops were greatly damaged as well. The National Policy Foundation held a talk recently to discuss the challenges Taiwan faces amid global climate change. How to reduce damages caused by sudden heavy downpours come as an important issue for policymakers and scientists around the globe. Geologists say that common natural disasters such as typhoons, rain, landslides, mudflows, and earthquakes all cause significant damages to the land. Flood prevention and mitigation measures need to consider local geography.

Wei Kuo-yen, Retired Professor, Dept. of Geosciences, National Taiwan University:”The problem with rebuilding the Mingbakelu Bridge that got swept away by the Laonong River is, you don't just build it higher. The mudflow came up 30 meters high this time, so how can you build the bridge any higher? This is the situation we're faced with and we need to think of some other solution.”

Some experts say that highly urbanized cities cannot rely solely on drainage systems, retention basins should be built to help overcome flooding problems.

Lee Hong-yuan, Professor, Dept. of Civil Engineering, National Taiwan University:”People think the government just expropriates land, digs a hole in it and turns it into a retention basin. But retention basin is a part of urban planning and it can be nicely designed. In both Taipei and New Taipei, the cost of buying the land takes up 80 percent of the money needed to build a retention basin, so the actual construction is not that expensive.”

Experts pointed out that municipalities need to cooperate when it comes to watershed management since rivers and streams run across cities and counties. Watershed management is ineffective if money gets wasted doing just parts of the work.

 

 

之前大雨造成中南部多處淹水、道路橋樑被沖毀、以及農產品受到損害,國家政策研究基金會舉辦座談,多位學者認為氣候變遷已經是全世界都要面對的問題與挑戰,各國政府只能想辦法降低瞬間大雨所造成的災害,地質學者分析,台灣的天然災害是很多因素加總造成的,像是颱風、大雨、山崩、土石流、與地震,都對土地影響很大,所以治水防災也需要將地質因素納入考慮。

台大地質系退休教授 魏國彥:「荖濃溪被沖毀的明霸克露橋,不是建高的問題,這一次的土石流堆積30公尺,你要建多高?因為我們已經是在這樣一個狀況下,你在那邊不可能終極解決這個問題。」

也有學者分析在都市地區,瞬間龐大雨量很可能超過都市的負荷,沒辦法只靠傳統排水設施,這還需要進一步透過都市計劃,像是設立滯洪池減少災害。

台大土木工程系教授 李鴻源:「大家都認為說徵收土地,去把它挖一個洞就叫滯洪池,不是的化整為零,跟你的地景全部結合在一起,一樣可以發揮功能。因為尤其在雙北,我們一個工程大概80%的工程款是拿來買土地的,真正拿來做工程的錢是不多的。」

學者們也都認為流域治理需要跨縣市合作,甚至由中央出面整合,才不會發生同一條河川上下游不同縣市,治水只做一半而且浪費預算的狀況。

相關新聞

專題|全台敬老金大調查