Lake volume and potential hazards of moraine-dammed glacial lakes – a case study of Bienong Co, southeastern Tibetan Plateau

• Published in: The Cryosphere
• Main Authors: H. Duan, X. Yao, Y. Zhang, H. Jin, Q. Wang, Z. Du, J. Hu, B. Wang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Glacial Lake; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-17-591-2023; https://doaj.org/article/f780bf32c0bf4a0a9ebedf6f7aeb4062

The existence of glacial lakes in the southeastern Tibetan Plateau (SETP) is a potential hazard to downstream regions, as the outburst of such lakes has the potential to result in disastrous glacial lake outburst floods (GLOFs). In the present study, we conducted a comprehensive investigation of Bienong Co, a moraine-dammed glacial lake in the SETP. First, the lake basin morphology was determined, and the lake volume was estimated, showing that the maximum lake depth is ∼181 m and the lake volume is <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>∼</mo><mn mathvariant="normal">102.3</mn><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">6</mn></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="68pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="aeea7b3d314ff5f150aa7a4958bf963e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-17-591-2023-ie00001.svg" width="68pt" height="14pt" src="tc-17-591-2023-ie00001.png"/></svg:svg> m 3 . These scenarios included the possibility of GLOFs being triggered by ice avalanches (Scenarios A1–3) from the mother glacier or by landslides from the lateral moraines (Scenarios B1–3 and C1–3). Avalanche volumes of the nine trigger scenarios were obtained from the Rapid Mass Movement Simulation (RAMMS) modeling results. Next, the Basic Simulation Environment for Computation of Environmental Flow and Natural Hazard Simulation (BASEMENT) model was used to simulate the generation and propagation of the avalanche-induced displacement waves in the lake. With the model, the overtopping flows and erosion on the moraine dam and the subsequent downstream floods were also simulated. The results indicate that the ice avalanche scenario may cause the largest mass volume entering the lake, resulting in a displacement wave up to 25.2 m in ...