Discharge of landslide-induced debris flows: case studies of Typhoon Morakot in southern Taiwan

作者：Chen J C^*; Chuang M R

来源：Natural Hazards and Earth System Sciences, 2014, 14(7): 1719-1730.

DOI：10.5194/nhess-14-1719-2014

Three debris-flow gullies, the Hong-Shui-Xian (HSX), Sha-Xin-Kai (SXK), and Xin-Kai-Dafo (XKD) gullies, located in the Shinfa area of southern Taiwan, were selected as case studies on the discharge of landslide-induced debris flows caused by Typhoon Morakot in 2009. The inundation characteristics of the three debris flows, such as the debris-flow volume V, deposition area Ad, and maximum flow depth, were collected by field investigations and simulated using the numerical modeling software FLO-2D. The discharge coefficient c(b), defined as the ratio of the debris-flow discharge Q(dp) to the water-flow discharge Q(wp), was proposed to determine Q(dp), and Q(wp) was estimated by a rational equation. Then, c(b) was calibrated by a comparison between the field investigation and the numerical simulation of the inundation characteristics of debris flows. Our results showed that the values of c(b) range from 6 to 18, and their values are affected by the landslide ratio R-L. Empirical relationships for c(b) versus R-L, Q(dp) versus Q(wp), Q(dp) versus V, and A(d) versus V are also presented.

• 出版日期2014