SHIMLA: A total of 934 fragile moraine-dammed lakes, an alarming phenomenon in the Himalayas, have been recorded in Himachal Pradesh and Tibet that could cause devastating floods, according to a state government study, here on Sunday. A moraine-dammed lake occurs when the terminal moraine has prevented some meltwater from leaving the valley. Its most common shape is that of a long ribbon.
The state-run Himachal Pradesh Council for Science Technology and Environment, which has been working to mitigate the climate-induced hazards, undertakes studies to understand the threats arising out of climate change.
With focus on research and mitigating strategies to combat the impact of climate change, the government set up the Centre for Climate Change under the State Council for Science Technology and Environment. It has been mapping all glacial lakes in the Himalayan region as they could cause large damage downstream on bursting.
It’s also studying the phenomena of flood due to of glacier lake outburst in various river basins, including the Satluj river catchment area in the Tibetan Plateau, by using the space data, said Rajneesh, Secretary (Environment, Science and Technology).
Flash floods are common in the state. In 2000, the Satluj Valley suffered the heaviest flood, causing over Rs 800 crore economic losses. The flood’s cause — cloud burst or glacial lake outburst — was not known as it happened in the Tibetan Himalayan region.
In 2004, formation of landslide-dammed lakes in high altitudes of Parchu, in the upper catchment area of Spiti in Tibet, caused huge threat to the life and property downstream.
Regular monitoring of the upper catchment areas having international dimensions was required, Rajneesh said.
According to the study in 2019, the Satluj basin has witnessed 562 lakes. Of this, 458 (81 per cent) are small with less than five hectares area, 53 (9 per cent) spread over 5-10 hectares, and the rest big with over 10 hectares area.
The Chenab basin, comprising Chandra, Bhaga and Miyar as sub-basins, has 242 lakes, the Beas basin, comprising the upper Beas, Jiwa and the Parbati, 93 lakes, and the Ravi basin 37 lakes.
In the Satluj basin alone, the number of glacial lakes increased by 352 between 1993 and 2013. Due to accelerated glacial melting in the Chenab, Ravi, Beas and Satluj river basins, 109 new lakes were formed between 2013 and 2015.
In view of the rising trend of lake formation in the Himalayan region, DC Rana, Council Member-Secretary, said the space technology had helped in studying high terrains.
The Centre on Climate Change had been undertaking the mapping and monitoring of all such lakes, he said and added, pre-assessment of the vulnerable lakes in Himachal or the adjoining Tibetan Himalayas, was important.
Lakes with area larger than five hectares could be considered the potential vulnerable sites for causing huge damages downstream, Rana said.
SS Randhawa, Principal Scientist with the Centre for Climatic Change, told IANS the aim of mapping glaciers and glacial lakes — an annual feature — was to assess the size of new lakes.
“We are collecting data regarding formation of new lakes and the rate of receding of glaciers,” Randhawa said. (IANS)
