Streamflow response to climate change in the Bago River Basin using SWAT+ hydrological model

ABSTRACT DEM, soil and land cover processed in QGIS to derive streamflow; SWAT+ model calibrated with observed data, bias-corrected GCM inputs used for future climate and impact assessment. Climate change is one of the most significant factors that can substantially alter hydrological processes, water resource management, agriculture, and flood control especially particularly in tropical river basins. This study investigates the impact of climate change on streamflow in the Bago River Basin, Myanmar, using the Soil and Water Assessment Tool Plus (SWAT+) and three General Circulation Models. The average annual precipitation is projected to increase by up to 25% under the SSP2–4.5 scenario and 20% under SSP5–8.5. However, the BCC-CSM2-MR model projects a slight decrease of about 10% under both scenarios. Average annual maximum and minimum temperatures are projected to increase by approximately 0.8–4.8 and 0.8–5.8 °C, respectively, under both scenarios. Projected streamflow changes range from −17.7 to 21.9% in the near future, −20.4 to 32.0% in the middle future, and −29.5 to 44.8% in the far future. The results indicate that climate change may intensify flood and drought risks, particularly under high-emission scenarios. The SWAT+ model effectively simulates future streamflow under changing climate conditions and underscore the urgent need for adaptive water resource management strategies. These strategies should address increasing flood and drought risks, as well as support sustainable agricultural and land-use planning.