Spatial heterogeneity in basin hydrology and hydropower potential: Implications for climate resilience and economic development in Nepal

Abstract Nepal's vast hydropower potential is central to its long‐term economic development; however, it exhibits pronounced spatial heterogeneity and is increasingly vulnerable to climate‐induced risks. This study employs an integrated, Basin‐scale analytical framework to evaluate the hydrological productivity and economic viability of major river Basins, explicitly linking these indicators to climate resilience. The results reveal a strong spatial concentration of water and energy resources, with the Koshi, Gandaki (Narayani), and Karnali Basins collectively contributing over 68% of the national runoff and accounting for more than 94% of the country's economically feasible hydropower potential. A key finding is the decoupling of Basin size from hydrological efficiency. The Mahakali Basin demonstrates the highest runoff intensity (4.07 million m 3 /km 2 /year), whereas the much larger Karnali Basin exhibits the lowest (1.08 million m 3 /km 2 /year). While theoretical and economic hydropower potentials are strongly correlated ( R 2 = 0.94), conversion efficiencies vary substantially across Basins due to site‐specific topographic, geological, and infrastructural constraints. Climate projections further indicate significant threats to hydropower reliability, including Basin‐specific reductions in mean annual flow of up to 48%, accelerated glacier retreat, and increased sediment loads. These risks are particularly acute given Nepal's heavy reliance on run‐of‐river hydropower projects. The study concludes that realizing hydropower potential in Nepal under a changing climate requires a strategic shift toward climate‐adaptive, Basin‐specific planning, emphasizing storage‐based hydropower, diversification of renewable energy sources, and strengthened transboundary water governance to ensure resilient and sustainable development.