Syllabus :GS3/Disaster Management
In News
Recently ,Nepal faced a severe Glacial Lake Outburst Flood (GLOF) on July 8, causing flash floods along the Lende river, destroying a China-built bridge and disabling hydro plants that supplied 8% of Nepal’s power.
| Do you know ? – With glacial melt increasing GLOF risks, Nepal has suffered repeated events, but lacks early warnings—especially for trans-boundary lakes in Tibet. – Nepalese officials criticized the absence of alerts from China despite rising risks. – Past major GLOFs in 1981, 1985, and 1998 highlight the urgency for cross-border early warning systems. Nepal has initiated mitigation efforts at some high-risk lakes, but more collaborative action is needed. |
What is Glacial Lake Outburst Flood (GLOF)?
- It is the sudden, catastrophic release of water from a glacier-formed lake, often dammed by ice, debris, or bedrock.
- They produce extreme peak discharges, far exceeding normal flood levels, and can trigger destructive debris flows due to their high erosion and transport power.
Causes
- Moraine or Ice Dam Failure: Weak structural integrity due to melting or seismic activity.
- Rising temperatures: Rising temperatures have led to rapid glacier melting, forming unstable moraine-dammed lakes
- Avalanches and Landslides: Sudden mass movements into lakes can displace water and cause dam failure
- Seismic Events: Seismic Activity: Earthquakes can destabilize moraine dams or trigger landslides.
- Heavy Rainfall and Cloudbursts: Excessive precipitation increases lake volume and pressure on natural dams.
Impacts of GLOFs
- Loss of Life and Livelihoods: Events like the 2023 South Lhonak lake breach in Sikkim killed over 100 people and displaced thousands.
- Infrastructure Damage: Bridges, roads, and hydropower projects are highly vulnerable.
- Environmental Degradation: GLOFs erode riverbanks, trigger landslides, and disrupt ecosystems.
- Economic Losses: Damage to power stations, transport networks, and agriculture leads to long-term economic setbacks.
Situation In India
- The Indian Himalayan Region (IHR), home to 11 river basins and 28,000 glacial lakes, faces growing threats from glacial lake outburst floods (GLOFs), driven by rising global temperatures and complex terrain.
- Two main lake types—supraglacial and moraine-dammed—are particularly vulnerable, with most GLOFs triggered by ice avalanches, landslides, or meltwater pressure.
- With 7,500 lakes located at high altitudes above 4,500 metres, monitoring is limited to remote sensing, which only tracks surface growth after the fact and offers little for early warning.
- Vulnerable downstream areas face severe risks to infrastructure, ecosystems, and lives, as seen in the 2023 South Lhonak GLOF in Sikkim and the 2013 Kedarnath disaster.
Government Response
- Central Government has approved National Glacial Lake Outburst Flood (GLOF) Risk Mitigation Project (NGRMP) for its implementation in four states namely, Arunachal Pradesh, Himachal Pradesh, Sikkim and Uttarakhand at a financial outlay of Rs.150.00 crore.
- India, through the National Disaster Management Authority (NDMA), is shifting from a post-disaster response approach to proactive GLOF risk reduction.
- Its Committee on Disaster Risk Reduction (CoDRR) coordinates central agencies, research institutions, and States/UTs to monitor and mitigate GLOF threats.
- A national programme was launched, initially focusing on 56 at-risk glacial lakes, now expanded to 195, ranked by risk level.
- The programme’s five key objectives are:Hazard assessment of glacial lakes,Installation of Automated Weather and Water Stations (AWWS),Deployment of Early Warning Systems (EWS) downstream,Risk mitigation through water drawdown or retention structures and Community engagement for preparedness and resilience
Progress
- India’s GLOF mitigation efforts have shown promising progress, with multi-institutional expeditions across J&K, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh returning successful outcomes.
- These teams conducted bathymetry, slope surveys, and Electrical Resistivity Tomography (ERT) to assess lake volumes and moraine dam stability.
- Community engagement proved essential, with local cooperation critical to success.
- Monitoring stations have been installed at two lakes in Sikkim, providing real-time weather and water data.
- In the absence of automated systems, the Indo-Tibetan Border Police (ITBP) assists with manual early warnings.
- More monitoring systems and expeditions are planned post-monsoon to close critical data gaps in the region.
Suggestions and Way Forward
- Improve Early Warning Systems and cell broadcast alerts in vulnerable zones.
- Transboundary Cooperation: Collaborate with Nepal, Bhutan, and China for upstream monitoring.
- Infrastructure Planning: Avoid critical installations downstream of high-risk lakes.
- Climate Adaptation: Integrate GLOF risk into broader Himalayan climate resilience strategies.
Source :TH
