Studies conducted by glaciologists have put a question mark over the large-scale exploitation of rivers for generating 21,000 MW of power in the state. “Himalayan glaciers are reacting to the climate change and man-made water bodies. The increasing traffic should be checked in high-altitude areas,” says Dr MR Bhutyani, a glaciologist and Joint Director, Snow and Avalanche Study Establishment, who presented his studies on five river basins at an international symposium on climate change here.

The annual discharge in the five river basins has declined during the past 82 years, but a significant decrease has been observed in the past two decades.

The rise of 1.7°C in the winter temperature has been felt significantly in the Chenab basin, which has the maximum number of 989 glaciers covering 2,280 sq km area in the north-west Himalayas. The Sutlej has 334 glaciers covering a 1,515 sq km area, the Beas has 277 glaciers with a 598 sq km area, while the Ravi has the minimum 94 glaciers covering a 210 sq km area.

Dr Bhutiyani, Vishwas Kale, and NJ Pawar said the discharge in Sutlej reached the maximum level in 1990 due to the melting of glaciers.

Because of the excessive melting during the pre-1990 period, most of the 334 glaciers had become thin considerably, they added.

They said studies conducted during the past four decades had established that the glaciers receded at a faster rate during this period.

Floods of high magnitude have been seen in the past five decades in these rivers: 10 in the Sutlej, six in the Chenab, five in the Ravi and four in the Beas. “Moreover, winters have been unusually warmer by about 4.4°C on an average during the past two decades,” says Dr Bhutiyani.

The winter discharge in the Chenab basin, a new area being exploited for power potential, has shown a significant increase between 1969 and 1998.

“It has a large number of glaciers, which are melting,” they observed.

The spring discharge in the Beas has decreased during the period from 1961 to 1995.