Surge in river volume across 10 per cent of the range boosts short-term water supply but raises sediment, hydropower and ecosystem risks

Rapid glacier melt driven by global warming has doubled the number of rivers in parts of the Himalayan region over the past decade, a study published in AGU Advances has found, a change that is reshaping water availability and risks for millions who rely on these waterways.

Researchers documented a surge in river volume across at least 10 per cent of the Himalayan range, including major basins such as the Indus, Yangtze, Amu Darya and Syr Darya. While the increase has temporarily bolstered supplies for agriculture, electricity generation and household use, scientists caution that the shift carries serious downsides.

The study, which examined the entire High Mountain Asia region and its river systems, noted that melting glaciers, altered snowmelt timing and changing rainfall patterns are combining to amplify river flows in many headwater areas. Short-term gains in water availability are being accompanied by higher sediment loads — sand, silt and gravel — which threaten to clog hydropower turbines and degrade sensitive aquatic habitats.

Researchers reported that the western Himalayas are experiencing larger increases in discharge than the eastern sectors, where rivers remain largely rain-fed. That geographic skew matters because hydropower is a critical lifeline for many communities in the western ranges, making them more exposed to both the benefits and the hazards of these hydrological shifts.

The findings build on earlier projections that glaciers across High Mountain Asia could lose between 29 per cent and 67 per cent of their mass by 2100, underscoring the dual nature of accelerated melt: an initial boost in run-off followed by long-term declines as ice reserves shrink. Scientists say the new, detailed discharge data can guide smarter siting of dams, inform sediment management and improve planning for water, energy and ecosystem resilience.

Policymakers and engineers face a narrow window to adapt infrastructure and management practices to the altered flows, the study’s authors argue, urging targeted sediment control, revised operating rules for reservoirs and cross-border cooperation where river basins span multiple countries. Without such steps, short-term water windfalls may translate into chronic supply volatility and damaged ecosystems once glacier stores dwindle.