They also make plantings to ensure the stability of slopes. Downstream the teams first assess the dimensions of the channels needed based on the watershed area and the potential rainfall there.
來到下游的土石流沉積區，則首先依集水區面積及降雨量，計算出所需的排洪斷面，同時疏浚沉積土石，以提供所需的斷面面積。