Scientists complete another study of glacial lake at Lhonak

EXPERTS FIND THE STILL GROWING SOUTH LHONAK LAKE TO BE RELATIVELY STABLE
GANGTOK, 19 Sept [IPR]: A team comprising of scientists and experts from the Sikkim State Remote Sensing Applications Centre [under Sikkim State Council of Science & Technology], Snow and Avalanche Study and Establishment of Chandigarh and State Disaster Management under Land Revenue Department completed a study of Lhonak lake in extreme North Sikkim.
The scientific expedition was carried out to undertake “Electrical Resistivity” survey of the moraines damming the South Lhonak Lake and the bathymetry survey which was finalized by the working group members constituted for the study of the South Lhonak Lake in 2013 by Department of Science and Technology, Government of India.
The study was supposed to be undertaken in the year 2013 but due to non availability of instruments, the expedition was undertaken only now. The window period for the study of the glaciers and glacial lakes is limited to two to three months (July to September) in a year.
Lhonak Lake is one of the largest glacial lakes formed in South Lhonak Glacier and its area has been rapidly increasing for the past few decades. At present, the lake has total area of 126 hectares with length of 2.30 km and breadth varying from 600 to 700 meters. The rapid increase of the lake volume and its area has drawn a serious concern in the state.
During the study, 3-D Electrical Resistivity survey was performed in the moraines to get resistivity characteristics against GLOFs. The survey was supposed to be conducted by SASE scientists but as they could not reach the lake, it was carried out by a team from Sikkim State Remote Sensing Applications Centre.
The data collected will be again processed for the final results.
The scientific team also conducted Lake Bathymetry with the help of rafts and Ultrasonic depth sounding equipment to calculate the depth of the lake. The maximum depth of the lake was recorded at 259 feet in the interior location of the lake.
High winds, continuous calving of glaciers, frequent snowfall and chilling cold during rafting on the lake has made Lake Bathymetry survey a risky and challenging task but despite the heavy risks, the scientific team from State Remote Sensing Applications Centre successfully completed the task.
Despite its huge size, the lake has shown good outlet which is a positive sign in terms of stability of the lake. But as the lake is in its formation process, a certain risk will be there as long as the lake does not attain complete formation. It will take another few years to shape complete formation of the lake.
The scientific team included Narpati Sharma (Assistant Scientific Officer), Pranay Pradhan and Radha Krishna Sharma (Project Scientists, Glacier Dynamics and Climate change studies), Mrs. Kesang Nima Bhutia, (Training Officer from Sikkim State Disaster Management Department).
During the expedition, the team from SASE-Chandigarh- Rajendra Parshad (Scientist), Reeta Rani and  Vikash Rana (Senior Research Fellows) returned from Muguthang due to ill health. They were evacuated from Muguthang by Army Helicopter to Gangtok on emergency basis. The Scientific expedition to the lake was started on 31 August and completed on 14 September 2014.
Sarla Rai, Special Secretary, Department of Science and Technology & Climate Change, Sikkim and Ambika Pradhan, the then Member Secretary, Sikkim State Council of Science and Technology were also the part of expedition team.
The Scientific team would like to thank ITBP and Defense personal based in Chaten, Thangu, Muguthang, 20-R, and Janak-2 for their outstanding support to the team during the expedition and special thanks to Kaushik Das, AIML, Kolkata for technical support during the entire field work in South Lhonak lake. Contributions of Rafters, porters, kitchen staffs etc in the field are highly acknowledged by the team. This is second visit of scientific team of State Remote Sensing Applications Centre to the lake after 2012.

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