Back analysis of the breach flood of the "11.03" Baige barrier lake at the Upper Jinsha River

Abstract

A second landslide took place in China on 3 November 2018 at the provincial boundary between Sichuan and Tibet. This landslide blocked the reach of the Jinsha River and created a barrier lake with a 5.79×108 m3 storage reservoir and a 31000 m3/s peak breach flood. To reveal the beach formation process of the barrier lake, this paper gathers the lake's geography and hydrology information and conducts material property tests including gradation, soil erosion, and shear strength experiments. Back analyzes on the dam breach hydrograph were conducted in tandem with the parametric sensitivity studies based on the tested knowledge using the DB-IWHR and DB-NHRI respectively. The measured results show that the theory, methods, and tools currently available for dam beach analysis can accurately predict the flood of a dam breach. Among the feedback regarding the hydraulic and geotechnical parameters, only those related to the relationship between the rate of erosion and shear stress are more important to the measured peak flow. The results from this study may provide a reference in the event of an emergency to other barrier lakes.