GLACIAL LAKE OUTBURSTS FLOOD

GLACIAL LAKE OUTBURSTS FLOOD

A GLOF refers to the flooding that occurs when the water dammed by a glacier or a moraine (accumulations of dirt and rocks fallen onto the glacier surface) is released suddenly. When glaciers melt, the water in glacial lakes accumulates behind loose, natural “glacial/moraine dams” made of ice, sand, pebbles, and ice residue.

GLOF IN INDIA

GLOF proneness of India

• Vulnerability of Hindu Kush-Himalayan Region (HKH): It has the maximum snow cover after the poles. The HKH region sustains more than 2 billion people directly and indirectly.
• Large numbers of glaciers in the HKH region: There are 8,800 glacial lakes in the Himalayas. Among these, more than 200 of these have been classified as dangerous.
• Soil is getting loose in the HKH region: The large human settlements and human activities have resulted in deforestation and large-scale agricultural activities in the region.
• HKH Assessment report: Even after fulfilling the commitments made under the Paris Agreement, one-third of the HKH region’s glaciers would melt and will potentially destabilize the river regime in Asia.
• Continued glacier melts in the Himalayas: Has slowly spawned over 5,000 glacier lakes that are dammed by potentially unstable moraines.

Tectonic activity in the region.

• The Indian plate is continuously moving north about 2 cm every year. So the Himalayas are rising about 5 mm a year. This makes the Himalayan region geologically active and structurally unstable.
• Landslides and earthquakes will continue to happen in the region. This can trigger a Glacial outburst.
• Example: The entire State of Uttarakhand is categorized as Zone IV (High-Risk Zone) and V (Very High-Risk zone) on the earthquake risk map of India.

GLOF Events

• Chamoli district in Uttarakhand: In February 2021, witnessed flash floods which are suspected to have been caused by GLOFs.
• Kedarnath tragedy in 2013
• In 1929, a GLOF occurred from the Chong Khumdan Glacier in the Karakoram. It resulted in a flood in the Indus River.

Possible reasons behind the Glacial burst

• Structural weakness: A build-up of water pressure or structural weakness of the boundary due to an increase in the flow of water.
• Tectonic or Cryoseism (non-tectonic seismic event of the glacial cryosphere) activities: Can cause GLOF. During this, the boundary of the glacial lake will collapse suddenly and release the water of the glacial lake.
• An avalanche of rock or heavy snow: During this, the water in the glacial lake might be displaced by the avalanche.
• Volcanic eruptions: Under the ice can lead to GLOF. These volcanic eruptions might displace the boundary or increase the pressure on the glacial lake or both.
• Heavy rainfall/melting of snow: This can lead to massive displacement of water in a glacial lake. Long-term dam degradation can also cause GLOF.
• Collapse of an adjacent glacial lake: Leads to a series of events that may trigger GLOF.

IMPACT OF GLOF

Economic

• Damage infrastructure: A fast-moving water flow with mud and debris can damage nearby infrastructure.
  • Example: A glacial burst on Nanda Devi washed away at least two hydroelectric power projects, the Rishiganga hydroelectric power project, and the NTPC Tapovan-Vishnugad project.
• Affect tourism: Areas that are prone to GLOF are also major tourism spots.
  • Ex: 2013 Kedarnath tragedy estimated $1 billion in tourism revenue loss for the year.
• Economic losses: Due to large impacts and damage, it may cause huge economic loss in restoration.
  • Example: In the 2013 Uttarakhand flood, more than $3.8 billion in total economic losses.

Social

• Loss of lives: The impact of flash floods due to GLOF is way more than common floods due to the lack of time, leading to high casualties.
  • Example: Kedarnath tragedy in 2013: Which left about 5000 dead and was also related to a glacial lake breach.

• Affect essential services: Due to the destruction of infrastructure like roads and bridges, there is a lack of access to essential services like hospitals, etc.
• Food shortage: Due to heavy flooding, it may destroy crops on mountain-like contour farms, which may lead to a shortage of food.
• Transhumance Communities: These communities are at the frontline, and their existence is threatened by the impact of the floods.

Environmental

• Forest Destruction: It can destroy and inundate downstream forests and forest covers.
• Habitat Destruction: Inundation of downstream habitats may be doom for native species of mammals and birds.
• Grazing Lands: High valleys and meadows are grazing lands for livestock in the high-altitude regions; glacial floods can destroy and inundate them.
• Loss of wildlife: Due to the high impact, animals are not able to take shelter and end up drowning in it.

GLOF MANAGEMENT FRAMEWORK IN INDIA

1. Risk Reduction Measures

• Identification of potentially dangerous lakes: Based on field observations, records of past events, geomorphologic and geotechnical characteristics of the lake/dam, etc.
• Use of Synthetic-Aperture Radar imagery: To automatically detect changes in water bodies, including new lake formations, during the monsoon months.
• Development of methods and protocols: To allow remote monitoring of lake bodies from space.
• Reduction of the volume of water: With methods such as controlled breaching, pumping, or siphoning out water, and making a tunnel through the moraine barrier or under an ice dam.
• Prohibition of construction of any habitation: In the high-hazard zone and relocation of existing buildings are to be relocated to a safer nearby region. New infrastructures in the medium hazard zone have to be accompanied by specific protection measures.

2. NDMA Guidelines for Reducing GLOFs:

• Identify and Mapping Dangerous Lakes: Potentially dangerous lakes can be identified. This identification will be based on field observations, past events, geomorphologic, and geotechnical characteristics, etc.
• Use of Technology: It has recommended the use of Synthetic-Aperture Radar imagery. It will automatically detect changes in water bodies, including new lake formations, during the monsoon months.
• Structural Measures: It recommends reducing the volume of water with various methods to manage lakes structurally. Methods are pumping or siphoning out water and making a tunnel through the moraine barrier or under an ice dam.
  • Example: In 2014, a landslide occurred along Phuktal (tributary to Zanskar river) in Kargil district of Ladakh. The NDMA created an Expert Task Force, which along with the Army, used explosives to channel water from the river.

• Land Use Planning: Land use planning regulations need to be developed. In downstream areas, infrastructure development should be monitored prior to, during, and after the construction.
• Trained Local Manpower: Apart from specialized forces such as NDRF, ITBP, and the Army, there is a need for trained local manpower. These teams will assist in planning and setting up emergency shelters, distributing relief packages, identifying missing people, and addressing the needs for food, healthcare, water supply, etc.
• Early Warning System: A robust early warning system in vulnerable zones should be put in place.
• Emergency medical response team: Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances should be set up in areas inaccessible by roads.
• Psychological Counselling: The guidelines also call for psychological counseling of victims.

3. India’s Preparedness

• Central Water Commission: Some work on the identification of such lakes has been done by the CWC.
• Work in progress: A robust early warning system, a broad framework for infrastructure development, construction, and excavation in vulnerable zones.
• Uniform codes: In contrast to other countries, there are no uniform codes for excavation, construction, and grading codes in India.

CHALLENGES

• No regulation for land-use planning: In the GLOF/LLOF prone areas, there are no widely accepted procedures or regulations in India.
• Less EWS stations: The number of implemented and operational GLOF Early Warning Systems (EWS) is still very small, even at the global scale.
• Lack of expertise: Due to complexities of many geographical factors, there is a lack of expertise in GLOF studies.
• Unplanned urbanization: Nowadays, hilly areas are getting high population density, which leads to unplanned urbanization and weak structures.
• High footfall: Due to high tourism, there is high footfall in these areas, which makes the evacuation strategies ineffective.

WAY FORWARD

• A long-term solution will be feasible: If all the countries start working towards reducing global warming.
• Need policy guidelines: India needs to form clear policy guidelines to restrict further human activities like building roads, constructing hotels on banks, etc. Any further human activity without proper guidelines will harm the already fragile landscape.
• Assessment: India needs to undertake a cumulative assessment and strategic planning.
• Use of technology: Geological Survey of India can use satellite images and technology like GIS (geographic information systems) and provide a clear analysis of the HKH region.
• Capacity building: Of the local community will ensure disaster mitigation in the near future.
• Set up EWS: The government has to be proactive and set up an early warning system in the Himalayas.