Taipei City Geotechnical Engineering Office

It is hot in summer. Mountains on the outskirts of Taipei are a great place to get away from the heat. Recently typhoons have hit Taiwan and it is raining all over Taipei. There is lots of water in the streams in the mountains. Be careful when you are near water and keep a safe distance from the river.

Chu Hsin An, Section Chief of Mud/Rockslide Control Section, Geotechnical Engineering Office, indicated that soil turns soft due to continuous rainfall. People must watch out for landslides and rock falls when going to the mountains. In recent years, due to the influence of global climate change, chances of extreme rainfall increase chances of these events significantly and sudden torrential rain causes flash flood in the mountain area. People must always be alert when going mountain climbing or visiting the river. The Taipei City Government set up drowning signs at the basins where people have drowned over the years, or where lots of tourists visit. Life-saving appliances are available at some basins to rescue
 people falling into the water. People may download the “Taipei City Disaster Prevention App” before going to the mountains to keep track of real-time weather updates (rainfall, water height and typhoon alert).

Three signs of a river flash flood

The terrain of basin varies. The sign of a flash flood at some rivers is that water becomes muddy or defoliated leaves and dead branches flow in the river.

Usually the water level in the front part of river course suddenly drops, hence water flows faster.

Before a flash flood occurs at some basins, the water level of river upstream is slightly higher than the original water level, and water flows gently at the same speed. When the river level rises "consistently", you only have five to ten seconds to get away from the flash flood.

Note: If you need to refer to photos, please search for and download them from the website of "Geotechnical Engineering Office, Public Works Department, Taipei City Government" (http://www.geo.gov.taipei/).