CHANDIGARH: The increasing number of fragile moraine-dammed glacial lakes in the Himalayas has raised the spectre of flash floods posing a threat to life and property downstream. According to a study conducted by the Himachal Pradesh State Council for Science Technology and Environment’s (HIMCOSTE) state centre for climatic change, there are 1017 such lakes in the region, up from 596 five years ago.
A moraine is the accumulation of silt, sediment and debris from melting glaciers which eventually blocks the flow of the glacier and turns the accumulated water into a lake. But given the fragile nature of the moraine, these lakes could burst their banks with any further pressure, leading to flash floods, technically called glacial lake outburst floods or GLOFs.According to the study, the glaciers in the Chenab, Ravi, Beas and Sutlej river basins in the state are melting at a faster due to climate change, resulting in the formation of more and more such lakes.
According to the study, based on monitoring of all such lakes in different river basins using LISS III satellite data, the Sutlej had a total 642 lakes in 2017 compared to 391 in 2013. Similarly, the Chenab basin has 220 lakes, up from 116 in 2013, the Beas has 101, up from 67, and Ravi river basin has now 54 lakes compared to 22 in 2013.
Adding to the concern is that the new lakes are mostly smaller (with areas less than 5 hectares) ones, which are more susceptible to GLOFs. Lakes with area of 10 hectares or less are seen as particularly vulnerable. The study states that a number of such glacial lake outburst floods have occurred in the Himalayas of Nepal recently, and notes that the 2013 flash floods in Uttarakhand occurred with bursting of the Parchu lake, which originates from Tibet in China.
“A proper monitoring and change analysis of all such lakes in higher Himalayan region of the State is critical for averting any future eventuality in Himachal Pradesh, so that precious human lives are saved,” says Kunal Satyarthi, member secretary of Himachal Pradesh State Council for Science Technology and Environment.