Uttarakhand’s First Glacial Lake Early Warning System

Context

Uttarakhand has initiated its first glacial lake early-warning system, which is real-time, at the Vasundhara Tal in Chamoli, after the previous practice of identifying and mapping the glacier lakes that pose a risk of a Glacial Lake Outburst Flood (GLOF).

Key Highlights

• Glaciers, snow cover, precipitation, and temperature are highly sensitive in the Himalayan region. Glacial lakes can become potentially hazardous when glaciers recede, or meltwater builds up behind the natural moraine or ice dam.
• GLOFs are caused by a sudden release of water stored in a glacial lake, creating a powerful downstream flood. The trigger may consist of:
  • A rock fall, avalanche, or landslide that enters a lake and displaces the water.
  • Failure or weakening of a moraine or ice dam.
  • Lake levels are rising as a result of the accelerated snow and glacier melt.
  • Extreme rainfall and other weather-related processes.
• In mountainous regions, the hazard is especially critical as flood water may flow quickly through narrow valleys, impacting settlements, roads, bridges, hydropower projects, and other infrastructure.
• In recent times, the Himalayan calamities have reflected the challenge of determining the exact cause of these calamities. There is now a greater need to monitor the scientific aspects continuously, and not just through periodic surveys.

From Mapping Glacial Lakes to Real-Time Monitoring

• In 2023, the NRC detected 344 glacial lakes in Uttarakhand. Of these, 13 are identified as ‘high risk’, including five as ‘high risk category A’ by the National Disaster Management Authority, of which Chamoli’s Vasundhara Tal is one.
• Previous work was directed towards determining the physical attributes of susceptible lakes from surveys. Six lakes have been surveyed for their bathymetry (depth and lake bottom properties).
• This information is also relevant as it allows scientists to understand the potential water volume that could be released in the event of a GLOF, and how the depth of the lake and water-holding capacity relate to this.
• This risk assessment framework is expanded with real-time instrumentation added to the new phase.

What Will the Vasundhara Tal System Monitor?

• This early-warning system will integrate the use of several sensors and communication technologies to create a comprehensive view of environmental and hydrological changes over time.

• Water-Level Monitoring

  • A sensor will measure the water-level changes in the lake. Any sudden or unexpected changes may be a valuable red flag to look into further.

• Weather Conditions

  • An automatic weather station will record parameters such as:
    • Temperature and humidity.
    • Rainfall.
    • Direction and speed of the wind.
    • Atmospheric pressure.
    • Light intensity.
  • Such data can be used to determine evolving conditions in and around the lake.

• Snow Conditions

  • Snow-depth and sub-surface temperature sensors measure the weather and changes in snow cover and temperature at various depths.
  • This can aid in understanding processes relating to snow and ice stability.

• Ground Movement and Vibrations

  • At selected locations, the tilt and accelerometer sensors will measure movements and vibrations. This type of data may be useful for detecting changes that could be caused by slope instability or other physical changes.

• Water Discharge

  • New water-flow sensors will be used to track changes in water levels as water exits the lake, giving another parameter to measure the water-flow behaviour.

How Will Data Reach Authorities?

• Vasundhara Tal is situated in a remote environment and is located at high altitude where traditional mobile connectivity is limited.
• The system will then be solar-powered with satellite communications to send information. Observations will be taken and recorded in a data logger, and a monitoring dashboard will alert if specific thresholds are exceeded. Satellite phones and low earth orbit communication devices are also being employed to keep the disaster management authorities in touch.
• This is especially significant as an early-warning system is only helpful if information flows rapidly from the hazard area to authorities and, ultimately, to communities downstream.

Why Does This Matter for Disaster Management?

• The project is a step towards anticipatory disaster management.
• Typically, the response following a disaster is an area of emphasis in traditional disaster management. Real-time monitoring can reinforce the pre-disaster phases of the disaster-management cycle:

• Protecting Vulnerable Infrastructure

  • Roads, bridges, hydropower facilities, transmission facilities and tourism facilities are in mountain valleys. Identifying unusual conditions early may help to prepare and limit exposure.

• Strengthening Scientific Disaster Management

  • Satellite observations, remote sensing, bathymetric surveys, weather data and geological studies are examples of inputs that sensor-based observations can complement.

• Building Climate Resilience

  • Glacier and snow changes can be altered by changes in temperature and precipitation. So, continuous monitoring can help to develop an understanding of the emerging hazards in a warming Himalayan environment.

• Improving Community Preparedness

  • Deaths can only be prevented if they are detected. People who live downstream need to be warned by having systems that get the message; evacuation plans; safe places; and frequent warning drills.

Challenges

• Difficult terrain: Installation, maintenance, and field visits are difficult in the remote areas of complex terrain.
• Technical and operational constraints: Satellite systems are vital but may have technical and operational limitations.
• Uncertainty of threshold: A change in water level, temperature, or movement of the ground does not necessarily indicate a GLOF is imminent.
• Extreme cold, snow and high-altitude maintenance: sensors need to be calibrated and maintained frequently during extreme cold, snow and high-altitude operation.
• Last mile connectivity: authorities need to translate technical alerts to meaningful messages for communities downstream.
• Multiple hazards: GLOF risk is frequently intertwined with landslide, avalanche, flash flood and extreme rainfall hazards; hence an integrated approach is needed.

Way Ahead

• Uttarakhand can learn from the Vasundhara Tal system and extend its early-warning system to the rest of the Himalayas.
• First, high-risk lakes, based on a common risk-assessment framework based on lake characteristics, downstream exposure and the probability of hazard, should be prioritised.
• Second, real-time sensor information needs to be combined with satellite-based remote sensing data, weather predictions, hydrological models and GIS-based vulnerability maps.
• Third, the early-warning procedure should be known by whom gets alerted, who verifies it, and who calls for evacuation.
• Fourth, downstream communities should be regularly trained in evacuation drills, local warning systems and disaster-awareness programmes.
• Last, lake monitoring should not be restricted to a lake-by-lake basis. Glacier, lake-ice, river and settlement systems should be evaluated as a whole, as a hazard from a high elevation lake can quickly travel downstream.

Source: The Indian Express

Mains PYQ

Q. With reference to National Disaster Management Authority (NDMA) guidelines, discuss the measures to be adopted to mitigate the impact of the recent incidents of cloudburst in many places of Uttarakhand. (2016)

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