Department of Geoinformatics, University of Kashmir, Hazratbal, Srinagar, 190006, Jammu and Kashmir, India.
Department of Geoinformatics, University of Kashmir, Hazratbal, Srinagar, 190006, Jammu and Kashmir, India.
Sci Total Environ. 2021 Feb 20;756:144008. doi: 10.1016/j.scitotenv.2020.144008. Epub 2020 Nov 27.
This study assessed spatiotemporal changes at Gya Glacier, the associated development of a proglacial lake, and reconstructed the 2014 outburst flood that struck Gya Village in the Trans-Himalayan region of Ladakh, India. This study analyzed and for the first time modeled a Glacial Lake Outburst Flood (GLOF) event in the Trans-Himalayan region of Ladakh. Glacier and glacial lakes changes were quantified using remote sensing data supplemented with field observations. Glacier ice-thickness and glacier-bed overdeepenings were modeled using a shear-stress based model, GlabTop (Glacier-bed Topography). The reconstruction of the 2014 GLOF and the potential hazard assessment of Gya Lake were carried out using the hydrodynamic model HEC-RAS; results were validated against ground-collected data. Temporal evaluation of satellite data revealed a 45.6% loss in the total glacier area between 1969 and 2019. The earliest snow-free image available for the region shows that a proglacial lake existed as early as 1969 with an area of 3.06 ha. The lake has expanded to ~11 ha in 2019. Results from the GlabTop model suggest that the lake could grow further up to 12 ha in the future. Field-based geomorphic indicators suggest that the 2014 GLOF event resulted from a piping failure of the frontal moraine destroying numerous agricultural fields, some buildings, downstream infrastructure, and eroded natural channel embankments. The reconstruction of the event revealed that 25% of the lake waters drained out with a peak discharge of 470 ms, inundating an area of ~4 km around Gya Village. However, a complete breaching of the terminal moraine could result in an event that would be 5.5 times larger than the 2014 GLOF. Therefore, this study could be useful not only in planning disaster-resilient infrastructure around proglacial lake environments in the cold-arid Ladakh but also in framing mitigation plans to reduce risk for vulnerable downstream communities.
本研究评估了印度拉达克 Trans-Himalayan 地区 Gyā 冰川的时空变化，以及与之相关的冰川前缘湖泊的发展，并重建了 2014 年袭击 Gyā 村的冰川湖突发洪水事件。本研究分析并首次对拉达克 Trans-Himalayan 地区的冰川湖突发洪水（GLOF）事件进行了建模。利用遥感数据结合实地观测，对冰川和冰川湖的变化进行了量化。利用基于剪切应力的模型 GlabTop（冰川床地形）对冰川冰厚度和冰川床超深进行了建模。利用水动力模型 HEC-RAS 对 2014 年 GLOF 事件进行了重建，并对 Gyā 湖的潜在灾害进行了评估；结果与实地收集的数据进行了验证。对卫星数据的时间评估显示，1969 年至 2019 年期间，总冰川面积减少了 45.6%。该地区最早的无雪图像显示，早在 1969 年就存在一个前缘湖，面积为 3.06 公顷。到 2019 年，该湖已扩大到约 11 公顷。GlabTop 模型的结果表明，未来该湖可能会进一步扩大到 12 公顷。基于实地的地貌指标表明，2014 年 GLOF 事件是由于前缘冰碛物的管涌破坏了许多农田、一些建筑物、下游基础设施和侵蚀了自然河道堤岸。该事件的重建显示，25%的湖水以 470ms 的峰值流量排出，淹没了 Gyā 村周围约 4 公里的区域。然而，终端冰碛的完全决口可能导致比 2014 年 GLOF 大 5.5 倍的事件。因此，本研究不仅对规划拉达克寒冷干旱地区冰川前缘湖泊环境的抗灾基础设施有用，而且对制定缓解计划以减少脆弱下游社区的风险也有用。
