Preprint Article Version 1 This version is not peer-reviewed

Debris Flow Generation Based on Critical Discharge: A Case Study of Xiongmao Catchment, Southwestern China

Version 1 : Received: 31 December 2019 / Approved: 2 January 2020 / Online: 2 January 2020 (04:47:49 CET)

How to cite: Gong, L.; Tang, C.; Xiong, J.; Li, N. Debris Flow Generation Based on Critical Discharge: A Case Study of Xiongmao Catchment, Southwestern China. Preprints 2020, 2020010012 (doi: 10.20944/preprints202001.0012.v1). Gong, L.; Tang, C.; Xiong, J.; Li, N. Debris Flow Generation Based on Critical Discharge: A Case Study of Xiongmao Catchment, Southwestern China. Preprints 2020, 2020010012 (doi: 10.20944/preprints202001.0012.v1).

Abstract

A debris flows generation related to a poorly sorted mixture of soil, catchment topography and rainfall characteristic. Runoff of some depth on valley resulting from intensive rainfall can incur the sediments movement of beds or adjacent banks. The fluid flow in channel affected by rainfall parameters combinations, such as duration, intensity, cumulative rainfall, etc., is the key factor for debris movement. In this paper, the rainfall characteristics and occurrence conditions of debris flow in Xiongmao gully on July, 26th, 2016, have been explored, combined with field survey and indoor simulation experiment on the collected critical discharge parameters of debris movement. Further, debris distribution and the critical discharge characteristics have been analysed, by means of investigation on the catchment topography and occurrence cause of the debris flow, analysis of the critical discharge parameters on which the channel debris began to move, and K value clustering analysis method to characterize the rainfall pattern of the studied area, the discharge calculation of debris flow occurring in different rainfall patterns. The results have shown that, for the debris flow occurrence in Xiongmao gully, the debris initiation on the middle reaches of the gully provide the majority of solid particles for the disaster on July, 26th, 2016, and the upstream confluent provided catchment. Based on the relationship obtained from laboratory test, in which the calculated critical discharge was 43.8m3/s, less than the peak discharge (Qc =66.7m3/s), calculated by morphological method. In addition, it has been indicated that the dominated rainfall patterns of the studied area are first-quartile and second-quartile, that is, the rainfall is primarily at earlier or middle to preliminary stage of this time rainfall event. The critical discharge for the occurrence of debris flow on July, 26th was achieved 20a rainfall frequency, the larger runoff volume generated on shorten heavily rainfall. Based on individuality characteristics, such as distributed hydrological analysis, critical discharge and rainfall pattern of debris flow, the forewarning could be more efficient.

Subject Areas

debris flow initiation; critical discharge; rainfall patterns; distributed hydrological

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