A new paper finds that, with modifications, the Chinese Glacial Lake Management System could be a promising tool to reduce the impacts of catastrophic glacial lake outburst floods (GLOFs) in the Himalayas.
GLOFs occur when water from glacial lakes – formed at the bottom, side, or within glaciers – suddenly breaches on account of slope failure, overtopping or other reasons. India has the second highest number of glacier lakes after China, numbering 508, according to the Central Water Commission. Almost 50% of larger lakes have increased in size by more than 20% from 2011 to 2023.
“Although the overall frequency of GLOFs has shown a weak decreasing trend over the past three decades, the damage to downstream communities and infrastructure has escalated due to rising exposure and vulnerability,” the study notes.
The Chinese Glacial Lake Management System (GLMS) operates through three core functions: The first is an automated early warning system based on monitoring data, which is disseminated through mobile networks and alarms. The second is engineering interventions on lake sites, such as siphon drainage, embankment reinforcement, and spillway construction. The third is having personnel or a department dedicated to managing glacial lakes, acting as coordinators between the central government, local agencies, and communities.
Before the GLMS was operationalised, 31 GLOFs occurred in China between 2005 and 2019, six of which caused significant damage, including the destruction of at least 88 buildings, around 71 km of roads, 30 bridges, and two fatalities. Between 2019 and 2023 – after the GLMS was operationalised – China experienced four GLOF events but minimal destruction and no fatalities. “Community participation and timely early warning mechanisms, where local managers successfully issued warnings for glacial lake outburst events, demonstrate the advantages of the “One lake, One chief” responsibility system in GLMS,” says the study.
By comparison, of the 16 GLOFs that occurred outside China in the same time period, seven caused damage to over 60 people, 58 bridges, 30 kilometers of roads, and 26,354 buildings. This includes the breach of the South Llonak lake in Sikkim.
Glacial lakes are projected to increase by around 377 kilometers in the future, nearly three times the extent mapped in 2000. The Central Himalayas, which fall in India, account for nearly 40% of this projected expansion, the study says. “A combination of early warning systems, engineering interventions, and community preparedness measures can significantly reduce GLOF risks. In particular, controlled water level drawdown has the potential to reduce flood intensity by up to 24%,” it says.
The Indian government launched the National Glacial Lake Outburst Flood Risk Mitigation Programme (NGRMP) in four states in 2024, in the aftermath of the Sikkim GLOF. The programme sets aside a budget of ₹150 crores (₹1.5 billion) for states to set up monitoring and early warning systems.
Banner image: The Kapuche Glacier Lake in Nepal. Image by Sarojpandey via Wikimedia Commons [CC BY-SA 4.0].