Efforts on to reduce GLOF disaster in Bhutan

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Nov 28: The first phase of an international project to reduce the risk of growing and increasingly unstable glacial lake bursts in Bhutan has started. 

In a joint effort by the government, communities and WWF, supported by the Global Environment Facility (GEF), the United Nations Development Program (UNDP) and the Austrian Coordination Bureau this year succeeded in lowering the lake water level by 86 cm, in the first phase of a project intended to artificially lower the water level at Thorthormi Lake by 5 meters in 3 years.

A team of over 300 workers from 20 districts of Bhutan and from all walks of life – tourist guides, farmers, women and yak herders – walked for up to 10 days to reach the site and dig and realign existing outlet channels to safely drain water from the lake. The team braved thin and frigid air and harsh weather conditions including the assault of Cyclone ‘Aila’ in May 2009. Heavy rains associated with the cyclone damaged access to the site and effort had to be shifted to repairing this.

Thorthormi Tsho is a glacial lake situated at 4428 m in the remotes Lunana. It is rated as one of Bhutan’s likeliest future catastrophes. Breach and outburst flood through Thorthormi Tsho’s unstable moraine walls would most likely spill into the also vulnerable Raphsthreng Tsho, 80 metres below, with the combined flood suddenly releasing up to 53 million cubic meters of water and debris into the upper catchment of the Pho Chu.

The valley had experienced Glacial Lake Outburst Flood (GLOF) in 1994 that more than people and devastated villages and wrecked transport and power facilities.

The Thorthormi Tsho burst will also invite crop destruction and livestock losses, loss of a vital bridge and roads, and damage to hydropower facilities under construction in Punakha and Wangdi valleys. Punakha Dzong is among 16 historic monuments at risk.

The Royal Government of Bhutan (RGB), monitoring the growth of the glacier with Japanese assistance, has sought assistance to reduce the dangers posed by the lake by artificially draining its waters.

Some 16 new glaciers and 82 glacial lakes have formed in Pho Chu headwaters alone.