The formation and the process of the debris flow are very complicated. So far the rainfall datum remains the most convenient and practicable method to judge whether the debris flow will take place or not. For the rainfall datum is convenient to obtain, and the range of its resources and materials are very extensive. Nevertheless, the rainfall data can neither explicate the detail of rainfall distributions, nor understand the geological state, which are the biggest blind spot for the debris flow’s warning system. Developing the hillside with no limit will accelerate the collapse of the mountain slope.

    Those slopes, which are easily to fall down, should be carefully coped with in order to prevent it from breaking up again:

    ●Method Used to Prohibit the Debris Flow: One should prevent channels from being eroded downward, and river banks from being eroded sideward. In this way, we could diminish the material and resource of the debris flow. Also, this kind of working technique includes how to make the riverbed stronger, and protect the river bank… etc.
    ●Method Used to Block the Debris Flow: While the material and resource of the debris flow in the valley or gully have accumulated to its saturation, once the heavy rain comes, it may possibly lead to the great calamity. After it comes, the best resolution to stop is to block the debris flow directly.
    ●Method Used to Deposit the Debris Flow: To deposit the debris flow, one can partly extend the stream valley or gully. This method is suitable to be utilized at the midstream of the river, where the debris flow happens frequently. In order to make the debris flow sink in the sand pool planned beforehand, what we have to do first is to broaden the width of the midstream, or reduce the slope of the riverbed. For example, we can build it in the form or shape of the ladder.

    ●Method Used to Dredge the Debris Flow: This type of method should be put into practice in following three places: first, the stream valley, second, the midstream or downstream of the gully, third, the fan ground of valley’s outlet. When the debris flow approaches, we can use the watercourse or the dredged channel to lure it flowing along the planed secure route.
    ●Area Prearranged to Buffer the Debris Flow: One can plant woods in this kind of area, which is placed at the end of the fan ground, in order to reduce the direct shock or damage from debris flows. Specifically, this is a sort of the area prepared for absorbing the attack.