Future Climate Risks in the Karnali River Basin in Nepal: Implications for Water, Energy, and Agriculture Sectors

Pradhananga, Saurav; Nepal, Santosh

Future Climate Risks in the Karnali River Basin in Nepal: Implications for Water, Energy, and Agriculture Sectors

Autores

Pradhananga, Saurav

Nepal, Santosh

Editor

International Water Management Institute

Descripción

Using the SWAT+ hydrological model driven by bias-corrected CMIP6 climate projections, analysis shows that the basin is expected to become warmer and wetter, with substantially higher monsoon rainfall and reduced precipitation during the winter and pre-monsoon seasons coupled with similar changes in flows. These seasonal shifts have far-reaching implications for Nepal's water, energy, and food security. Although the planned 900 MW Upper Karnali Hydropower Project could benefit from increased annual energy generation due to higher wet season flows, dry season power production is projected to decline by up to 15%, precisely when electricity demand is often highest. Likewise, irrigation water requirements for both paddy and wheat are expected to increase as rising temperatures and reduced winter rainfall intensify crop water stress. These findings challenge the assumption that greater annual rainfall automatically leads to improved water security. Instead, they show that the timing, distribution, and management of water resources will become increasingly critical. More intense monsoon runoff will heighten flood risks, while reduced dry season flows may constrain irrigation, hydropower production, and environmental flows, increasing competition among water users. These changes underscore the need to strengthen climate resilience across the water sector. This study recommends integrating climate-informed hydrological projections into hydropower feasibility studies, design standards, and energy planning to avoid underestimating future risks. Investments in multipurpose storage reservoirs, improved irrigation efficiency, climate-responsive crop calendars, and enhanced flood and drought preparedness will be essential to manage growing seasonal variability. Adopting an Integrated River Basin Management approach that coordinates water allocation across sectors while safeguarding ecosystem needs will be critical to ensuring sustainable and climate-resilient development in the Karnali River Basin.