It is feared that this monsoon, the Tsho Rolpo lake -- the largest glacial lake of Nepal -- may burst. If adequate disaster management strategies are not drawn up, the Tolwaling Valley, lying at the foot of the Gauri Shankar range, will witness massive destruction. The aerial distance of the lake from Kathmandu is 110 km.
The Tsho Rolpo lake is three-kilometer long and half-a kilometer wide, with a total surface area of about 1.37 sq km. The maximum depth is 135 m and the volume of water stored is about 75-80 million cu m. According to experts, the ice core is melting rapidly, endangering the moraine dam (which has stagnant glacial ice) and increasing the flood risk.
As mitigation measures, two strategies have been proposed by experts. The first includes establishing an early siren system at 16 villages lying below the lake. This will enable the people to have enough time to escape the impending disaster. The construction of such a system is expected to start in September, reported the department of hydrology and meteorology ( dhm) .
The second strategy is to reduce the water level of the lake by installing siphons. A project proposal to this effect, was submitted to the Dutch government in April 1996 for funding. A dhm representative said, "The dhm is keen to materialise the project in order to safeguard the lives and properties of the inhabitants and vital infrastructures of Rolwaling Valley and other areas downstream."
About 12 years ago, a similar disaster had struck when the Dig Tsho glacier in the Khumbu region had burst on August 4, 1985. When a glacier breaks, torrential water rushes downstream, becoming a dangerous floodwave, known as the glacial lake overburst flood ( glof ). After the Dig Tsho incident, the government of Nepal has accorded top priority to glof studies, a vital area for the development of the water resources of the country.