The water level of Thorthomi Lake has been successfully lowered by five metres this month. The mitigation works at Thorthomi Lake in Lunana started in 2008, after studies revealed Thorthomi Lake as one of the potential lake posing threats downstream.
The actual excavation works of the Thorthomi Lake began only in 2009.
In this year’s working season which began in July, the lake was reduced by 1.32 metres. Due to man power shortage, more than 100 Royal Bhutan Army personnel helped in lowering the water level this year.
The Director General of the Department of Geology and Mines, Sonam Yangley, said the progress made this year at the site was tremendous despite inhospitable working condition. “Due to the help from the Royal Bhutan Army, we were able to meet the set target this working season. We have now met the target of five meters which was not an easy task. We could only get about 50 people to work at the site so we had to request for help.”
The Director General also said by reducing the water level, the risk of the glacial outburst has also reduced. However, he added that safety cannot be guaranteed as unpredictable natural disasters such as quakes and global warming can trigger outburst of the lake.
“It is a risk reduction project not eradication. We cannot fight with nature but I must say we have managed to reduce the risk. The water which we released is about 17 million cubic meters of water which is equivalent to the flood of 1994. So by reducing the water level by this much means less risk because even if there is outburst the force and pressure won’t be the same,” said Sonam Yangley.
The mitigation works were carried out by the Department of Geology and Mines under the National Adaptation Programme of Action with funds from the least developed countries fund. It was co-financed by the United Nations development programme, Austrian development cooperation, WWF and the RGoB.
