Modelling the Impact of Climate Change in Hydrology of Tamor River Basin

Climate change has emerged as a major challenge for water resources and hydropower generation in the Himalayan region, where rivers are highly sensitive to shifts in temperature and precipitation. This study investigates the potential impacts of climate change on the hydrology of the Tamor River Basin in Near Future (2026AD-2050AD), Mid Future (2051AD-2075AD) and Far Future (2076AD-2100AD). A combination of observed hydro meteorological data from the Department of Hydrology and Meteorology (DHM) and bias-corrected climate projections from CMIP6 under SSP245 and SSP585 scenarios were employed. The HEC-HMS model was calibrated and validated using discharge records from Majhitar(Q684) and Mulghat(Q690) stations, achieving strong statistical performance (NSE= 0.668, R²= 0.7213, and PBIAS=+18.61%) during validation period(2020AD-2024AD) at Mulghat station(Q690), confirming its reliability for flow simulation in the basin. Monthly water flow variations in the SSP245 scenario could range from -27.28% in the dry season and -34.80% in the wet season in the near future(2026AD-2050AD),-27.30% to -34.60% in the mid future(2051AD-2075AD) and -29.64% to -34.80% in the far future(2076AD-2100AD).Under the SSP585 scenario, variations might range from -26.14% to -34.93% in the near future(2026AD-2050AD),-24.21% to -33.86% in the mid future(2051AD-2075AD) and -19.62% to -31.64% in the far future(2076AD-2100AD).