Indian Institute of Technology Roorkee, 247667 Roorkee, Uttarakhand, India.
Indian Institute of Technology Roorkee, 247667 Roorkee, Uttarakhand, India.
Sci Total Environ. 2019 Jun 10;668:362-378. doi: 10.1016/j.scitotenv.2019.02.388. Epub 2019 Feb 28.
The presence of glacial lakes in the Himalaya makes it a potential mountain hazard, as catastrophic failure of such waterbodies may lead to high-magnitude glacial lake outburst flood (GLOF) events that can cause significant damage to the low-lying areas. The present study evaluates the hazard potential of the South Lhonak lake located in the state of Sikkim, using both one and two-dimensional hydrodynamic modeling approaches. Different breach parameters were calculated based on the lake bathymetry and moraine dimensions. The worst-case GLOF scenario is revealed during an overtopping failure of the moraine, producing a peak flood of 6064.6 m s and releasing a total water volume of 25.7 × 10 m. The GLOF hydrograph is routed to calculate peak flood (m s), inundation depth (m) and flow velocity (ms) along the main flow channel. The interaction of the flood wave with a major topographic obstruction located 15.6 km downstream of the lake, shows a significant reduction of the flow energy leading to a minimization of the South Lhonak GLOF impact. The flood wave reaches the nearest town Lachen, located at a distance of 46 km downstream from the lake, at 3 h 38 min after the initiation of the breach, with a peak flood of 3928.16 m s and a maximum flow velocity of 13.6 ms. At Chungthang town, located at a distance of 62.35 km from South Lhonak lake, the flood wave potentially inundates settlements along the bank of the flow channel, where a peak flood of 3828.08 m s is reached after 4 h of the initial dam breach event. The study also incorporates modeling of a framework to propose a potential flood remediation measure of the South Lhonak lake GLOF by demonstrating the effect of a lateral inline structure along the flow channel, to check the flow of the potential flood wave.
位于喜马拉雅山的冰川湖使其成为潜在的山地灾害，因为这些水体的灾难性失效可能导致大规模的冰川湖突发洪水（GLOF）事件，从而对低地地区造成重大破坏。本研究使用一维和二维水动力模型方法评估了位于锡金邦的南隆纳克湖的灾害潜在风险。根据湖泊水深和冰碛尺寸计算了不同的决口参数。在冰碛物的漫顶失效期间，揭示了最坏情况的 GLOF 情景，产生了 6064.6 m/s 的峰值洪水，并释放了 25.7×10 m 的总水量。GLOF 洪水过程线被用来计算主河道沿程的峰值洪水（m/s）、淹没深度（m）和流速（ms）。洪水波与位于湖泊下游 15.6 公里处的一个主要地形障碍物的相互作用，显示出水流能量的显著减少，从而使南隆纳克 GLOF 的影响最小化。洪水波到达距离湖泊下游 46 公里的最近城镇拉钦，在决口后 3 小时 38 分钟，峰值洪水为 3928.16 m/s，最大流速为 13.6 ms。在距离南隆纳克湖 62.35 公里的宗塔昂镇，洪水波可能淹没河道两岸的定居点，在最初的大坝决口事件 4 小时后，达到 3828.08 m/s 的峰值洪水。该研究还纳入了一个框架模型，通过演示沿河道的侧向直线结构的效果，提出了南隆纳克湖 GLOF 的潜在洪水补救措施，以检查潜在洪水波的流动。
