气候变化领域集成服务门户(CCPortal): Modeling the glacial lake outburst flood process chain in the Nepal Himalaya: Reassessing Imja Tsho's hazard

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DOI	10.5194/hess-22-3721-2018
	Modeling the glacial lake outburst flood process chain in the Nepal Himalaya: Reassessing Imja Tsho's hazard
	Lala J.M.; Rounce D.R.; McKinney D.C.
发表日期	2018
ISSN	1027-5606
起始页码	3721
结束页码	3737
卷号	22 期号:7
英文摘要	The Himalayas of South Asia are home to many glaciers that are retreating due to climate change and causing the formation of large glacial lakes in their absence. These lakes are held in place by naturally deposited moraine dams that are potentially unstable. Specifically, an impulse wave generated by an avalanche or landslide entering the lake can destabilize the moraine dam, thereby causing a catastrophic failure of the moraine and a glacial lake outburst flood (GLOF). Imja-Lhotse Shar Glacier is amongst the glaciers experiencing the highest rate of mass loss in the Mount Everest region, in part due to the expansion of Imja Tsho. A GLOF from this lake may have the potential to cause catastrophic damage to downstream villages, threatening both property and human life, which prompted the Nepali government to construct outlet works to lower the lake level. Therefore, it is essential to understand the processes that could trigger a flood and quantify the potential downstream impacts. The avalanche-induced GLOF process chain was modeled using the output of one component of the chain as input to the next. First, the volume and momentum of various avalanches entering the lake were calculated using Rapid Mass Movement Simulation (RAMMS). Next, the avalanche-induced waves were simulated using the Basic Simulation Environment for Computation of Environmental Flow and Natural Hazard Simulation (BASEMENT) model and validated with empirical equations to ensure the proper transfer of momentum from the avalanche to the lake. With BASEMENT, the ensuing moraine erosion and downstream flooding was modeled, which was used to generate hazard maps downstream. Moraine erosion was calculated for two geomorphologic models: one site-specific using field data and another worst-case based on past literature that is applicable to lakes in the greater region. Neither case resulted in flooding outside the river channel at downstream villages. The worst-case model resulted in some moraine erosion and increased channelization of the lake outlet, which yielded greater discharge downstream but no catastrophic collapse. The site-specific model generated similar results, but with very little erosion and a smaller downstream discharge. These results indicated that Imja Tsho is unlikely to produce a catastrophic GLOF due to an avalanche in the near future, although some hazard exists within the downstream river channel, necessitating continued monitoring of the lake. Furthermore, these models were designed for ease and flexibility such that local or national agency staff with reasonable training can apply them to model the GLOF process chain for other lakes in the region. © 2018 Author(s).
语种	英语
scopus关键词	Buildings; Chains; Climate change; Erosion; Floods; Glacial geology; Hazards; Personnel training; Rural areas; Catastrophic damage; Catastrophic failures; Downstream impacts; Empirical equations; Environmental flow; Glacial lake outburst flood; Potentially unstable; Simulation environment; Lakes; avalanche; catastrophic event; climate change; flood; flooding; glacial lake; glacier retreat; hazard assessment; hydrological modeling; lake level; landslide; model validation; momentum; moraine; outburst; river channel; wave generation; Himalayas; Imja Glacier; Khumbu Himal; Lhotse Shar Glacier; Mount Everest; Nepal; Sagarmatha [(ADS) Nepal]
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159977
作者单位	Lala, J.M., Center for Water and the Environment, University of Texas at Austin, Austin, TX, United States; Rounce, D.R., Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, United States; McKinney, D.C., Center for Water and the Environment, University of Texas at Austin, Austin, TX, United States
推荐引用方式 GB/T 7714	Lala J.M.,Rounce D.R.,McKinney D.C.. Modeling the glacial lake outburst flood process chain in the Nepal Himalaya: Reassessing Imja Tsho's hazard[J],2018,22(7).
APA	Lala J.M.,Rounce D.R.,&McKinney D.C..(2018).Modeling the glacial lake outburst flood process chain in the Nepal Himalaya: Reassessing Imja Tsho's hazard.Hydrology and Earth System Sciences,22(7).
MLA	Lala J.M.,et al."Modeling the glacial lake outburst flood process chain in the Nepal Himalaya: Reassessing Imja Tsho's hazard".Hydrology and Earth System Sciences 22.7(2018).