河か道どう閉へい塞そく

noun

natural damming of a river

Technical term used in geology and disaster prevention for a river blocked by a landslide, debris flow, or similar mass movement.

• 地じ震しんによる河か道どう閉へい塞そくが下か流りゅうの洪こう水ずいリスクを高たかめた。

  The natural damming of the river caused by the earthquake increased the flood risk downstream.