over-66-himalayan-lakes-in-high-risk-category-for-flooding

A government report reveals that glacial lakes and water bodies across the Himalayan region have experienced a notable area expansion of 10.81 per cent from 2011 to 2024, a change driven largely by climate change and raising concerns about the risk of glacial lake outburst floods (GLOFs).

According to the report by the Central Water Commission (CWC), Indian glacial lakes saw an even more dramatic increase, with a 33.7 per cent expansion in surface area.

"The total inventory area of glacial lakes within India was 1,962 hectares during the year 2011 which has increased to 2,623 hectares during the year 2024 (September). There is a 33.7 per cent increase in area," the report stated.

The findings highlight 67 lakes in India that have experienced over a 40 per cent increase in surface area, categorising them as high-risk for potential GLOFs.

Notable expansions were observed in Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh, emphasising the need for enhanced monitoring and disaster preparedness.

The report indicated that the overall area of glacial lakes and water bodies in the Himalayan region has surged from 533,401 hectares in 2011 to 591,108
hectares in 2024, also as a consequence of climate change.

The rapid growth of these lakes has been linked to accelerated glacier melting due to rising temperatures, posing severe threats to downstream communities, infrastructure, and biodiversity.

"Physically, the shrinking of mountain glaciers and expansion of glacial lakes are amongst the most recognisable and dynamic impacts of climate warming in this environment," the report noted.

The CWC has underscored the urgency of monitoring these changes, especially since catastrophic floods can occur when glacial lakes breach their natural moraine dams, releasing vast amounts of water downstream.

As such, the Commission highlighted the necessity of rigorous monitoring and immediate risk management strategies.

To tackle the challenges of tracking these remote lakes, a senior official from the CWC indicated that advanced satellite technology has been leveraged, particularly the Sentinel-1 Synthetic Aperture Radar (SAR) and Sentinel-2 multispectral imagery, which facilitate precise and all-weather monitoring.

"The high-resolution capabilities of these satellites allow CWC to detect changes in lake size with 10-metre accuracy, even in challenging conditions such as cloud cover. This monitoring technology is critical in providing timely updates on the state of these high-risk lakes, thereby enabling early interventions when necessary," the official explained.

The report also points to the transboundary risks presented by expanding glacial lakes in neighbouring countries such as Bhutan, Nepal, and China. Given the interconnected nature of river basins in the Himalayan watershed, collaboration with these countries is essential for effectively managing the potential impacts of GLOFs.

The report calls for joint monitoring efforts and data sharing to enhance risk assessment and mitigation strategies.

It stresses the urgent need for international and regional cooperation in establishing early warning systems, refining disaster management plans, and increasing community awareness initiatives to protect vulnerable populations.

The expansion of glacial lakes poses broader implications beyond flooding risks, potentially affecting water availability in major regional river systems, including the Ganga, Brahmaputra, and Indus.

By using data from 2011 and comparing it with five and ten-year averages, the CWC has identified patterns of glacial lake expansion, enabling authorities to pinpoint high-risk areas.

The aforementioned official confirmed that the CWC is committed to reducing monitoring intervals and improving data precision, with the goal of establishing a robust system for early detection and response to the evolving challenges posed by Himalayan glacial lakes.

Additionally, the Indian Space Research Organisation had in 2023 released a sporting stating the increase in melting of Himalayan glacial lakes in an extensive rate.

"Satellite data archives spanning the past 3 to 4 decades provide valuable insights into changes occurring in glaciated environments. Long-term satellite imagery covering the catchments of Indian Himalayan river basins from 1984 to 2023 indicates significant changes in glacial lakes," the ISRO reports states.

Of the 2,431 lakes larger than 10 hectares identified during 2016-17, 676 glacial lakes have notably expanded since 1984.

Specifically, 130 of these lakes are situated within India, with 65, 7, and 58 lakes located in the Indus, Ganga, and Brahmaputra River basins, respectively, it added.

Of these lakes: 601 lakes (89%) have expanded more than twice, 10 lakes have grown between 1.5 to 2 times, and 65 lakes at 1.5 times.