Riyaz Bhat
Srinagar, Sep 2: The sudden shifts in water volume due to rapid melting of glaciers or lake outbursts can lead to devastating floods in the areas around the river Chenab, reveals a risk assessment of Glacial Lake Outburst Floods (GLOF) Kishtwar.
The risk assessment, the risk of GLOFs in Kishtwar, arises from the combination of natural factors and climatic conditions that influence glacial lakes’ behaviour.
The risk assessment states that the components form the basis of the GLOF risk assessment for the region include glacial retreat and lake formation, moraine dam stability, seismic-activity-and landslides and hydrological changes,
“The glaciers in the Kishtwar Himalayas are retreating at an accelerated pace due to rising temperatures, leading to the creation of new glacial lakes. Existing lakes are also expanding, increasing the water volume held behind unstable moraine dams,” it reads.
It also states that the lakes such as Mundiksar Lake and Hangu Lake, both classified as high-risk, are prime examples of expanding lakes in this region. This expansion heightens the potential for catastrophic dam failure.
The document further states that many glacial lakes are formed behind moraine dams, which consist of unconsolidated glacial debris. These natural dams are prone to failure due to their unstable structure.
“Factors such as increased water pressure from lake expansion, earthquakes, or heavy rainfall can lead to sudden breaches, causing GLOFs. Lakes like Patla Pani Lake categorized as moderate-risk, are also susceptible to GLOFs if their moraine dams fail,” it reads.
It also reads that the steep terrain of the region exacerbates the risks associated with GLOFs, as floodwaters can travel swiftly through narrow valleys, causing widespread damage downstream.
“The Chenab river, fed by glaciers and glacial lakes, is sensitive to changes in the region’s hydrology. As lakes expand, there is an increased risk of sudden outflows, which could impact the river’s course and flood surrounding areas,” it reads.
It also states that “The changes in the water balance of these glacial lakes are continuously monitored, but sudden shifts in water volume due to rapid melting or lake outbursts could lead to devastating floods.”
The report states that a comprehensive risk assessment and mitigation plan is critical to safeguard the lives, property, and infrastructure of downstream communities in Kishtwar.
It states that to minimize the impact of GLOF events a regular-monitoring-and, early warning-systems need to be put in place. “Continuous monitoring of high-risk glacial lakes is critical for early detection of any significant changes in water volume or dam stability. Establishment of Early Warning Systems (EWS) should include collaboration with the Indian Meteorological Department (IMD) to predict weather conditions that could trigger GLOFs. These systems will enable authorities to issue timely alerts to vulnerable communities and ensure evacuation measures are in place,” the report states.
“In cases where glacial lakes pose an imminent threat, engineering interventions should be considered. These include: -Controlled drainage of high-risk lakes to reduce the pressure on moraine dams. This can be done by creating artificial channels or tunnels to release excess water in a controlled manner. -Reinforcement of moraine dams using structural materials to stabilize them and prevent collapse. Where feasible, geotechnical studies should be conducted to assess dam stability and determine the most effective reinforcement methods.”
The report suggests: “The DDMA in collaboration with all the stake holders should conduct a comprehensive risk mapping of the region to identify areas most vulnerable to GLOF events. This should include detailed assessments of downstream communities, critical infrastructure (such as roads, bridges, and power plants), and agricultural areas that could be affected by floodwaters. Areas identified as high-risk should be prioritized for disaster preparedness measures, including the creation of buffer zones and evacuation routes.”
“Local communities in Kishtwar must be educated about the risks of GLOFs and trained in emergency response. Regular awareness campaigns should be conducted to inform residents about warning signs of GLOFs, evacuation procedures, and how to respond during a flood event or other events caused by GLOF(s),” it adds.
