A recent comprehensive study by IIT-Roorkee, published in Hydrological Processes, has shown that groundwater discharge plays a far more important role than glacier melt in sustaining the Ganga River’s flow during the dry summer months — especially in the plains up to Patna. 

Key findings:

Glacier melt makes negligible contribution to summer discharge once Ganga leaves the Himalayan foothills.

Groundwater discharge boosts the river’s volume by nearly 120% along the stretch through the plains.

Over 58% of the river’s water is lost to evaporation during summer.

The aquifers in the central Ganga Plain appear more resilient than previously thought. While there are concerns about over-extraction and diversion, the pattern of flow implies a still-active underground system feeding the river. 

Implications:

River rejuvenation efforts like Namami Gange and the Jal Shakti Abhiyan need to accord much greater importance to groundwater recharge, preservation of tributaries, and sustainable flow releases from barrages and dams.

Policy must shift from glacier-centric narratives toward protecting the river’s connection with its underground sources.