Impacts of climate change on hydrological patterns and implications for hydroelectric power generation in Khimti River Basin, Nepal

Abstract

Climate change has considerable influence on mountain environments and the related hydrological processes, in turn affecting hydropower. Climatic unpredictability and rising temperatures cause soil water depletion, leading to unpredictable downstream runoff. This study examines the consequences of climate change on hydrological regimes and their effect on hydropower production in Khimti River basin of Nepal. This study used the soil and water assessment tool (SWAT) in the shared socioeconomic pathway (SSP2 4.5 and SSP5 8.5) emission scenarios of three climate models (CanESM5, MIROC6, and MRI-ESM2-0) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The study encompassed recorded temperature and rainfall data to correct errors. River discharge data were utilized for calibration and validation the SWAT model, leveraging 21 hydrological parameters. The result revealed that the projected stream flow is higher than the observed flow in all seasons except CanESM5 for the monsoon season from 2023 to 2074. Results showed the average annual flow increased by 0.2–54% in all time intervals for both scenarios. The excess energy power generation and economic benefits increase extensively in the future, with the greatest contribution during the spring season followed by the winter season. The information obtained from this study can be useful for policymakers, planners, and investors for hydropower generation in Nepal.