GLACIAL LAKE OUTBURST – ENVIRONMENT

GLACIAL LAKE OUTBURST – ENVIRONMENT

News: Millions in India, Pakistan at risk of flooding from glacial lakes

What's in the news?

●       Around 15 million people across the world face the risk of sudden and deadly flooding from glacial lakes, which are expanding and rising in numbers due to global warming, according to a new study.

●       More than half of those who could be impacted live in four countries such as India, Pakistan, Peru and China.

Glacial Lake Outburst:

●       Glacial lakes result from shrinking glaciers. Once the water is released from them, it could cause flooding in the downstream areas. This is known as glacial lake outburst floods or GLOF.

●       The GLOFs have been taking place since the ice age, the risk has increased multifold due to climate change.

Three main features:

1. They involve sudden (and sometimes cyclic) releases of water.
2. They tend to be rapid events, lasting hours to days.
3. Furthermore, they result in large downstream river discharges (which often increase by an order of magnitude).

Causes:

1. Structural weakness:

●       A buildup of water pressure or structural weakness of boundary due to an increase in the flow of water.

2. Earthquake:

●       An earthquake (Tectonic) or cryoseism (non-tectonic seismic event of the glacial cryosphere) can also cause GLOF.

●       During this, the boundary of the glacial lake will collapse suddenly and release the water in the glacial lake.

3. Volcanic eruptions:

●       Volcanic eruptions under the ice can also cause GLOF. These volcanic eruptions might displace the boundary or increase the pressure on glacial lakes or both.

4. Heavy rainfall/melting of snow:

●       This can lead to massive displacement of water in a glacial lake.

5. Impact of Climate Change:

●       Climate change has driven erratic weather patterns like increased snowfall and rainfall, warmer winters have led to the melting of a lot of snow.

Mitigation measures:

NDMA guidelines:

1. Identify and Mapping Dangerous Lakes:

●       Potentially dangerous lakes are often identified.

●       This identification are going to be supported by field observations, past events, geomorphologic and geotechnical characteristics, etc.

2. Use of Technology:

●       It is recommended to utilize the Synthetic-Aperture Radar imagery.

●       It will automatically detect changes in water bodies, including new lake formations, during the monsoon months.

3. Structural Measures:

●       It recommends reducing the number 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.

●       Constructions and development in High prone areas should be prohibited. It's a very efficient means to reduce risks at no cost.

4. Land Use Planning:

●       Land use planning regulations need to be developed.

●       In downstream areas, Infrastructure development should be monitored before, during, and after the construction.

5. Empowered Local Manpower:

●       Apart from specialized forces like NDRF, ITBP, and the military, there is a requirement for trained local manpower.

●       They can assist in planning and fixing emergency shelters, distributing relief packages, identifying missing people, and addressing the requirement for food, healthcare, water, sanitation, etc.

6. Early Warning System:

●       A robust early warning system in vulnerable zones should be put in place.

7. Emergency response team:

●       Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances should be found in areas inaccessible by roads.

WAY FORWARD:

1. Identification of potentially hazardous lakes:

●       By using field observations, historical event records, the geotechnical and geomorphologic characteristics of the lake or dam, and the surroundings, it is possible to identify potentially dangerous lakes and determine additional physical problems.

2. Improvement of early warning systems:

●       Even on a global scale, there are very few GLOF early warning systems that have been implemented and are in operation.

●       Three instances of the use of sensor and monitoring-based technical systems for GLOF early warning in the Himalayan region have been documented (two in Nepal and one in China).

3. Uniform codes for construction activity:

●       Establishing a comprehensive framework for excavation, construction, and infrastructure development in vulnerable areas.

●       In areas where GLOFs are likely to occur, land use planning procedures must be accepted.

4. Training local people:

●       Since residents are often the first to respond to a disaster before trained rescue personnel, it is important to train them in search and rescue procedures.