Status: this discussion paper is a preprint. It has been under review for the journal Natural Hazards and Earth System Sciences (NHESS). The manuscript was not accepted for further review after discussion.
Glacial lake change risk and management on the Chinese Nyainqentanglha in the past 40 years
Wang Shijin
Abstract. The paper analyzed synthetically spatial distribution and evolution status of moraine-dammed lakes in the Nyainqentanglha Mountain, revealed risk degree of county-based potential dangerous glacial lakes (PDGLs) outburst floods disaster by combining PDGLs outburst hazard, regional exposure, vulnerability of exposed elements and adaptation capability and using the Analytic Hierarchy Process and Weighted Comprehensive Method. The results indicate that 132 moraine-dammed lakes (> 0.02 km2) with a total area of 38.235 km2 were detected in the Nyainqentanglha in the 2010s, the lake number decreased only by 5 %, whereas total lake area expanded by 22.72 %, in which 54 lakes with a total area of 17.53 km2 are identified as PDGLs and total area increased by 144.31 %, higher significantly than 4.06 % of non-PDGLs. The zones at very high and high integrated risk of glacial lakes outburst floods (GLOFs) disaster are concentrated in the eastern Nyainqentanglha, whereas low and very low integrated risk zones are located mainly in the western Nyainqentanglha. On the county scale, Nagque and Nyingchi have the lowest hazard risk, Banbar has the highest hazard and vulnerability risk, Sog and Lhorong have the highest exposure risk. In contrast, Biru and Jiali have the highest vulnerability risk, while Gongbo'gyamda and Damxung have lowest adaptation capacity. The regionalization results for GLOF disaster risk in the study are consistent with the distribution of historical disaster sites across the Nyainqentanglha.
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State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu, 730000, China
GLOF is low-frequency event, but it often causes enormous loss and damage of life, property and human environment in downstream regions. The economic losses caused by GLOF are much higher than the project costs to early consolidate moraine dam and release flood waters. Glacial lake outbursts can be very difficult and expensive to control, but regional exposure and vulnerability of exposed elements downstream can be reduced by improving adaptation capacity and risk management level.
GLOF is low-frequency event, but it often causes enormous loss and damage of life, property and...
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