20 Oct

Glacial Lake Outburst Flood (GLOF)

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Contents

• Introduction
• Glacial lakes: Moraine Dammed/ Ice Margin dammed
• Causes of increasing GLOF
• Steps taken so far
• Key Highlight of the NDMA Guidelines

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Introduction

GLOFs are sudden fast flowing release of glacial lake water that move downslopes as a result of dam failure. They are recognized in the National Disaster Management Plan (NDMP) 2019 of India as a potential climatological disaster.

Glacial lakes are either moraine dammed or ice margin dammed.

Moraine Dam Glacial Lakes are formed due to the retreating of glaciers, which leave behind soil and rocks and lead to an increase in capacity of lake, making it prone to bursting.

Ice Dam Lakes are created when ice from upper parts of glaciers fall and block passing rivers, giving rise to glacial lakes.

Different types of lakes may have different hazard potential:

For e.g. Moraine-dammed lakes have high probability of breach and hazard potential, whereas the rock dammed lake have little chance of breach and low hazard potential.

Current Situation:

A study, ‘Glacial Lake outburst floods threaten million globally’ published in the journal Nature in Feb 2023 highlights that:

• Around 15 million people globally face the risk of GLOF.
• Around 20% of them (3 million) live in India.
• India, Pakistan, Peru and China have more than 50% of the vulnerable people.

Causes of increasing GLOF

• Global Warming -> Climate Change
  • Increasing number of Glacial Lakes due to acceleration of glacier melt in recent decades.
  • Increased water pressure due to more water being available due to Global Warming.
• Ice or rock avalanches, Erosions or other natural disruptions
• Earthquakes – Himalayan region is especially prone to earthquakes
• Human Activities -> increased tourism, expansion of roads and hydropower projects,
  deforestation etc have also increased the vulnerability of burst in these lacks.

Adverse Impact

• These floods pose severe geomorphological hazards and risks
  •  It can wreck havoc on all man made structures located along the path and thus endanger people, infrastructure, fields and livestock.
    • For e.g. the Chamoli Flash floods of 2021 may have caused economic damages worth Rs 4,000 crore. It swept away the Rishiganga Hydel Power Project and inflicted substantial damage on the Tapovan Power Project.
    • Similarly, the Kedarnath flash flood in 2013 was caused by GLOF.
  • Long term Climate Impact may be caused by large glacial lake as they would  increase the amount of water in ocean and reduce it in Himalayas.

Steps taken so far:

• CWC has done some work towards identification of such lakes;
  • Some other aspects are still work in progress including a robust early warning system, and a broad framework for infrastructure development, construction and excavation in vulnerable zones.
• Geological Survey of India (GSI) carries out assessment of the GLOF threats and provide input to the National Disaster Management Authority (NDMA) for developing risk mitigation strategies.
• National Disaster Management Authority (NDMA) in collaboration with Swiss Agency for Development and Cooperation (SDC) have prepared Guidelines on the Management of Glacial Lake Outburst Floods (GLOFs) (Oct 2020)
  • The guidelines are aimed at improving the administrative responses, drawing on
    international best practices; and bringing together the relevant scientific capabilities of the nation to eliminate potential losses from glacial hazards.

Key Highlight of the NDMA Guidelines

i. Inventorization: Hazard and Risk Mapping

• Regular monitoring of glacial lakes using satellite observations.
• Cooperation with neighbouring countries (Nepal, Bhutan and China) to identify transboundary threats and manage it properly.

ii. Reduction of Hazards

• Short term actions – lowering the lake level through siphoning
• For instance, high density PVC pipes were installed in South Lhonak lake in Sikkim,
  to reduce the pressure on the lake

Long Term Actions

• Artificial drainage channels to lower lake levels
• Reinforcement of dam
• Enhancement of river cross section/ protection from erosion

Restricting constructions and development in GLOF prone areas is a very efficient means to reduce risks at no cost.

Develop regulation for Land Use Planning in GLOF areas.

iii. Reduction of Exposure

• Establishment of Early Warning System.
• Comprehensive alarm system – including classical alarming infrastructure as well as modern technology using smart phone notifications etc.
• Evacuation based on EWS
• Involve local population closely from the beginning in the design, planning and
  implementation of risk reduction and management strategies in a transparent
  collaboration mechanism.

iv. Awareness and Preparedness through posters, social media, apps etc.
v. Capacity Development 

• Apart from specialized forces such as NDRF, ITBP, and the ARMY, the guidelines emphasize on need for trained local manpower.
• Training of professionals and practitioners;
• Strengthening Academic Education in relevant disciplines from natural and social
  sciences.
• Heavy earthmoving and search and rescue equipment, as well as motor launches,
  country boats, inflatable rubber boats, life jackets etc.
• Setting up Quick Reaction Medical Teams, mobile field hospitals, Accident Relief
  Medical Vans, and heli-ambulances in areas inaccessible by roads.

vi. Promote R&D in GLOF Management

• Promote development of Modelling tools to simulate the entire chain of mass
  movement and outburst process
• Historical records should be effectively used to understand flood processes.
• Expand the use of local knowledge, experience of local people. Engaging the local
  population in joint-knowledge production is considered indispensable for effective
  community based disaster risk management.

vii. Regulation and Enforcement

• A well drafted techno-legal regime is necessary to prevent future development of GLOF and protect existing Glaciers.
• The regime should include a Himalaya GLOF mitigation Policy, no habitation and
  construction zones; and provisions for strict implementation.

Other steps

• Need of a nodal agency to coordinate all the researches related to glaciers in the region .
• Fighting Climate Change
• Sustainable Development
  • Restricting Tourism in these areas or promoting only sustainable tourism
• Detailed Project Reports and Environmental and Social Impact Assessment needs to take into account the Glaciology study to better understand the impact of these projects on glaciers and glacial lakes.

International Cooperation: GLOF risk is transboundary in nature, thus there is an urgent need for a comprehensive regional risk governance framework including India, Nepal, Bhutan etc.

Example Questions

• Discuss the key factors which is making Himalayan region more vulnerable to Glacial Lake
  Outburst floods (GLOF). In light of the recent NDMA guidelines, suggest measures to reduce risks of GLOF disasters (15 marks, 250 words)