Study on the Early Warning System Optimization of Jintou Gully Debris Flow in Southwestern China

Abstract

It is a top priority to reduce the underreport and misreport rates and make the early warning system more effective. This study employed methods including early dynamic identification of debris flows, rainfall pattern analysis, geotechnical testing, and triggering tests further to optimize this gully’s critical rainfall early warning indicators. The study proposed a multi-stage, multi-process comprehensive early warning system to reduce debris flow’s under report and misreport rate. First, the adequate peak acceleration and Standardized Precipitation Index before the 2015 Jintou Gully debris flow outbreak revealed that earthquakes and wet/dry cycles often influence the debris flow of loose and bare soil, so debris flow is more likely to occur under the effect of rainfall. Therefore, the implementation of the early dynamic prediction of debris flow plays a crucial part in debris flow early warning. Second, the critical rainfall indicators need further optimization. The critical rainfall threshold should be put forward comprehensively with rainfall patterns. Third, the debris flow is a typical viscous debris flow formed by the liquefaction of loose bare soil after shear contraction. Dual fractal dimensions, small initiation scale, rapid confluence process, and destructive solid power characterize it. Fourth, the scientific training of new researches for monitoring and early warning decision maker is the important chain in the system. They can initiate the early warning system immediately based on technical defence signals to reduce underreporting and misreporting rates only if they fully understand the research results on the debris flow triggering mechanism.