Gangotri Glacier study by IIT Indore reveals climate-driven shift in River Ganga's water flow

A new scientific study has revealed that climate change is altering the water composition flowing from the Gangotri Glacier System (GGS), the source of the River Ganga in the central Himalaya.

- BISWAJEET BANERJEE

LUCKNOW:

Over the last four decades, researchers say, snowmelt contribution has declined, while rainfall-runoff and baseflow are gradually increasing—a trend that could reshape the river's seasonal flows and impact millions dependent on its waters.

The study was carried out by the Glaci-Hydro-Climate Lab at IIT Indore and modelled streamflow from 1980 to 2020. Using the high-resolution Spatial Processes in Hydrology (SPHY) model, calibrated with field discharge records, geodetic satellite-based glacier mass balance data and snow cover maps, the researchers offered the most detailed breakdown yet of the glacier-fed river system.

According to the findings, snowmelt continues to dominate the Gangotri catchment, contributing 64 per cent of annual discharge, followed by glacier melt at 21 per cent, rainfall-runoff at 11 per cent, and baseflow at 4 per cent. But the balance has shifted over time. Snowmelt has been steadily declining, while rainfall-runoff and baseflow have inched upward.