Impact of climate change: Snow cover declines in major river basins of Himachal Pradesh
Rapidly changing climate is degrading the snow cover of Himalayan rivers originating in Himachal Pradesh, according to a recent study by the Himachal Pradesh state council for science technology and environment’s (HIMCOSTE) state centre for climatic change.
The study shows that the snow cover in the major rivers originating in the Himalayas in Himachal Pradesh has declined. Major rivers like Chenab, Beas, Parvati, Baspa, Spiti, Ravi,Sutlej and their perennial tributaries originating from Himalayas depend upon the seasonal snow cover for their discharge. Seasonal snow in the Himalayan rivers play a major role in controlling their hydrology.
The centre for climatic change used satellite data of 2017- 2018 to estimate snow cover in these rivers. The data was compared with that of average values estimated during the period 2016-2017. The study comes as a warning for state’s snow-fed rivers which are dependent on the seasonal snow cover for their discharge.
Analytical data shows that the Chenab basin, which is located on north of Pir Panjal Range, behaves differently in comparison with the southern basins for winter precipitation. The snow melt has been more on the southern portion of Himalayas compared to the northern side of Pir Panjal Range.
The Ravi river basin, which is on the southern side of Pir Panjal Range, also shows less snowfall area during 2017- 2018. The Chenab basin received more snow between November and December while the snow cover declined December onwards.
“There is an overall reduction in the area under seasonal snow cover during the winters of 2017-18 in comparison to the area as observed during 2010-16 period in Himachal Himalaya” said Kunal Satyarthi, Member Secretary HIMCOSTE.
The research showed that the river basins experienced more snow during December and November whereas the snow cover declined from January to March of 2017-2018.
The northern basins of Chenab and Sutlej show a reduction of snow cover area in the month of October by 35% and 37% respectively. In the winter, the studies showed there is a marginal reduction in the months of January and February by 2% each in Chenab basin and 9% and 6% respectively in Sutlej basin during the same period, while in November and December it showed a positive trend with 16% and 10% increase in Chenab basin and 14% and 48% in Satluj basin.
The Ravi and Beas basins which are on the southern side of the Pir Panjal range, showed negative trends in the months of October, January, February and March. The reduction in snow cover in these months was 67%, 51%, 30% and 16% respectively in the Ravi basin while the figures for the Beas basin were 24%, 28%, 19% and 8%.
In November and December the snow cover showed an increase in area by 20% and 43% in the Ravi basin and 5% and 40% in the Beas basin.