Monitoring and simulation of typical glacial lake outburst debris flow in Xizang, China

In the Himalayan region, the floodwater from glacial lakes burst down at high speed and debris is taken by the flood along the way, resulting in burst debris flows. Dynamic change analysis and debris flow outburst simulations were conducted for two glacial lakes in the Nianchu River Basin by using the FLO-2D model based on remote-sensing image data collected from 1989 to 2023. Indeed, all frequent burst floods would evolve to burst debris flows after ice lake bursts. The results show that the areas of the Shi’e Lake and the Shimo Lake have increased by 0.36 km² and 1.02 km², respectively, in the past 34 a. FLO-2D simulations revealed that outburst debris flows could affect maximum areas of 17.6 and 13.5 km², with peak velocities reaching 17.36 and 11.52 m/s for the Shi’e Lake and the Shimo Lake, respectively. The average annual melting rates of Shi'e Glacier and Shimo Glacier are 0.071 and 0.027 km²/a, respectively. Additionally, risk zoning maps were generated to identify high, medium, and low hazard areas. This study provides a scientific basis for land-use planning, risk assessment and disaster mitigation in downstream areas.

This study proposes a prediction glacial lake prediction model using FLO-2D model.