Glacial lake outburst flood hazard assessment by satellite Earth observation in the Himalayas (Chomolhari area, Bhutan)

Abstract

Abstract. A case study of glacial lakes outburst flood (GLOF) hazard assessment by satellite Earth observation (EO) and numerical modelling is presented for the supraglacial and ice-contact lakes on Thangothang Chhu glacier, Chomolhari area (Bhutan). Detailed geomorphological mapping, including landslide and rock glacier inventories, as well as surface displacement determination using an interferometric SAR (InSAR) satellite, allowed a GLOF hazard assessment for lake Wa-007 to be performed. Outburst scenario modelling was achieved by combining both empirical and numerical modelling approaches, revealing that only a flood wave can have an impact on the two human settlements located downslope of Wa-007 lake. The worst-case scenario, modelled thanks to r.damflood, allowed the wave-front arrival time, the maximum water depth and the arrival time of maximum water height for the two human settlements to be quantified. A long-term monitoring strategy based entirely on EO data, with an update cycle of 5 years, is proposed to assess the future evolution of the area.

Modeling Potential Glacial Lake Outburst Flood Process Chains and Effects From Artificial Lake‐Level Lowering at Gepang Gath Lake, Indian Himalaya

“…For future work, we recommend regular monitoring of the lake and its surroundings using remotely sensed data. InSAR techniques can be helpful to monitor slope movements or moraine instability (Bertone et al., 2022; Scapozza et al., 2019; Wangchuk et al., 2022). Real‐time water‐level sensors can be used to monitor the lake‐level fluctuations and downstream water levels.…”

A Critical Review of Water Resources and Their Management in Bhutan

“…Unpredictable rainfall patterns and sudden heavy rainfalls during the monsoon due to climate change have increased the chances of flash floods in some of the river catchments of Bhutan [100]. Frequent flash floods and landslides were observed in the southern region of Bhutan in 2000 and 2004 when they received sudden heavy rainfall, which damaged properties, highways, agricultural lands, irrigation channels, and water supply schemes.…”

The Status of Earth Observation Techniques in Monitoring High Mountain Environments at the Example of Pasterze Glacier, Austria: Data, Methods, Accuracies, Processes, and Scales

“…To assess rock glacier movement rates, DInSAR was successfully applied to determine displacement rates [75][76][77]. Landslide, rock glacier movement rates, and, e.g., surface displacement mapping using DInSAR was determined in order to assess hazards related to GLOFs [78].…”