When Typhoon TORAJI attacked Taiwan in2001, there occurred serious debris flow disaster, and from then on, the occurrence frequency of debris flow has been very high so we took Chen-Yu-Lan stream watershed as the research material.

• 位于台湾中部之浊水溪的支流之陈有蘭溪集水区，因數十年前新中横公路之开辟，加上1999年九二一大地震时最接近震央，均生成了大量之土石松方。