2025/9/23 因為颱風帶來的豪雨，使馬太鞍溪上游一座堰塞湖崩塌，相當於六千座奧運標準泳池的水瞬間衝向下游，大量土石和泥沙淹沒花蓮光復鄉，造成巨大災害。

Barrier Lake Caused Flooding in Guangfu, Hualien
花蓮光復鄉堰塞湖災害

On September 23, Super Typhoon Ragasa brought heavy rain to Hualien, Taiwan. A barrier lake on the Matai’an Creek burst, sending water rushing down the valley and flooding Guangfu Township. The muddy water carried rocks and washed away  bridge. The water also damaged roads and houses. After the disaster, thousands of volunteers showed up with shovels and buckets to clean up the thick mud.

1. What is a barrier lake? 什麼是堰塞湖？
   A barrier lake forms when rocks or landslides block a river’s flow. The water can’t flow, so it gathers behind the block and makes a temporary lake.
   
2. Why is a barrier lake dangerous? 堰塞湖為什麼危險？
   The “wall” that blocks the river is just mud and rocks, so it isn’t strong enough to last long. When it rains too much, the weak “wall” can break suddenly and cause big floods.
   
3. How big is the Matai’an barrier lake? 馬太鞍堰塞湖有多大？
   When the barrier lake it was full, it held about 91 million tonnes of water. That’s like 34,000 Olympic swimming pools!