Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 14, 1719-1730, 2014
https://doi.org/10.5194/nhess-14-1719-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
14 Jul 2014
Discharge of landslide-induced debris flows: case studies of Typhoon Morakot in southern Taiwan
J.-C. Chen and M.-R. Chuang Dept. of Environmental and Hazards-Resistant Design, Huafan University, New Taipei, Taiwan
Abstract. 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 cb, defined as the ratio of the debris-flow discharge Qdp to the water-flow discharge Qwp, was proposed to determine Qdp, and Qwp was estimated by a rational equation. Then, cb 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 cb range from 6 to 18, and their values are affected by the landslide ratio RL. Empirical relationships for cb versus RL, Qdp versus Qwp, Qdp versus V, and Ad versus V are also presented.

Citation: Chen, J.-C. and Chuang, M.-R.: Discharge of landslide-induced debris flows: case studies of Typhoon Morakot in southern Taiwan, Nat. Hazards Earth Syst. Sci., 14, 1719-1730, https://doi.org/10.5194/nhess-14-1719-2014, 2014.
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