Overdevelopment and confusion over flood prevention policies and measures are to blame for the floods that occurred in ares of Taipei and New Taipei City (新北市) recently after torrential rainfall hit the two municipalities, environmentalists said yesterday.
While many may be under the impression that Taipei and New Taipei City have the best flood prevention systems in the country, the heavy rainfall that soaked them week have proven the idea wrong, the environmental group Green Formosa Front said.
“Recent torrential rainfall and flooding are sending warning messages to Taipei and New Taipei City,” Front board member Lin Chang-mau (林長茂) said. “It may be time to think more profoundly about flood prevention.”
A good flood prevention system should start in the mountains where the water comes from, he added.
“In Taipei and New Taipei City, the surrounding mountains have been overly developed with entire communities located there,” he said. “This could interfere with the capacity of the soil to absorb water, causing water to run down from mountains, making the flooding issue more serious.”
When it comes to Taipei, Taiwan Academy of Ecology secretary-general Tsai Chih-hao (蔡智豪) said that non-integrated flood prevention policies and concretization mean flooding is inevitable.
“Currently, the responsibilities of river management and flood prevention are divided between the central and local governments,” Tsai said. “The major rivers that flow through cities — such as the Tamsui River (淡水河) between Taipei and New Taipei City — fall under the jurisdiction of the central government’s Water Resources Agency — while minor creeks and drainage systems fall under local governments.”
He said the Water Resources Agency is only concerned about not letting water from the river flood the city, so they have built embankments “but, in turn, embankments also block flood water in the city from flowing out into the river. However, the Water Resources Agency doesn’t care.”
Tsai added that rivers flowing through Taipei used to have more “flooding space,” but now the embankments have constricted that space.
“Central and local governments really have to work together to come up with an integrated policy to prevent flooding,” he said.
Taiwan Academy of Ecology consultant Chang Feng-nian (張豐年), an expert in flood prevention, said Taipei and New Taipei City should be more careful in closing the water gates that control the flow of water from drainage channels into rivers.
“The city governments close water gates whenever there’s torrential rain to prevent water in a river from flowing into the city through drainage channels,” Chang said. “But at locations where the ground is higher, the water only flows from drainage channels into a river, so closing the gate would actually block the normal flow of water, and cause flooding in the city.”