Anthropogenic drivers and their impact on the hydrological regime of Nepal: a review

Nepal’s hydrological regime, shaped by steep topography, monsoon-dominated rainfall, andextensive cryospheric systems, offers a useful testbed for understanding how climate change andhuman activities are reshaping water resources in mountain regions globally. Despite abundantwater sources, Nepal faces persistent water security challenges driven by extreme seasonality, risingtemperatures, shifting precipitation patterns, and rapid land-use change. In this review, we synthesize current evidence on anthropogenic drivers of hydrological change in Nepal and draw lessons relevant to other data-sparse, high-mountain and monsoon-influenced regions. We findthat warming-induced glacial retreat, altered snowmelt timing, and changing monsoon dynamics are intensifying wet-season flood risks while heightening dry-season water scarcity, patternsincreasingly observed across the Himalaya, Andes, and other mountain systems. Human activities,including urban expansion, agricultural intensification, hydropower, and extraction of sedimentsfrom rivers, further modify river flows, reduce groundwater recharge, and increase vulnerabilityto extremes. Yet major uncertainties persist, especially concerning high-elevation hydrology, permafrost dynamics, sediment extraction, and the cumulative impacts of expanding infrastructure.Nepal’s pronounced topographic and climatic gradients limit broad generalizations, underscoring the need for region-specific hydrological monitoring and modeling. These challenges mirrorglobal limitations in mountain hydrology, where sparse observations and rapidly changing conditions constrain predictive capacity. By identifying key knowledge gaps and highlighting cascadingimpacts on agriculture, hydropower, domestic water supply, and aquatic ecosystems, this reviewemphasizes the urgency of strengthening monitoring networks and integrating uncertainty intowater management and climate adaptation strategies. Nepal’s experience offers broader insights forcountries facing similar pressures at the intersection of climate change, development, and fragilemountain water systems.