Hydrological responses of the Brahmaputra river basin using CMIP6 GCM projections for supporting climate resilient infrastructure design
Faruque Abdullah, Wasif Bin Mamoon, A. K. M. Saiful Islam, GM Tarekul Islam, Sujit Kumar Bala, Shadman Kaiser, Khaled Mohammed, Maruf Billah, Mohan Kumar Das
Abstract
The central northern region of Bangladesh has a low density and quality of sustainable rural infrastructures, and it is frequently affected by climate change-induced seasonal flooding and associated river erosion. This study used the Soil and Water Assessment Tool (SWAT) hydrological model to simulate future discharges under moderate and extreme Shared Socio-economic Pathway (SSP) scenarios, utilizing 13 bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) General Circulation Models (GCMs). Using these flow projections, the 1D HEC-RAS hydrodynamic model was then simulated to assess future water level fluctuations in six major rivers in the study region. The results indicate that the dry season will experience a more notable flow increase (up to 45%) than the wet season (up to 42%) compared to the baseline under the extreme scenario by 2100. The subsequent rises in water levels will also be significant in the major rivers in the Brahmaputra-Teesta River system. Based on these future water level changes, the study has prepared a guideline for building climate-resilient infrastructures in the study area.