Assessing the impacts of climate change on flooding under Coupled Model Intercomparison Project Phase 6 scenarios in the river Chenab, Pakistan

This study evaluates various climate scenarios on flooding by identifying future streamflow, flow change and floodplain flows regarding future greenhouse gas emissions. Various general circulation models (GCMs) were utilized to create historical (1986-2014) and future (2022-2100) scenarios to assess the risk of flooding due to changes in flow under future climatic conditions using Coupled Model Intercomparison Project Phase 6 (CMIP6). The delta correction (DC) method was used to correct biases in the CMIP6 data to reduce uncertainty. Based on precise multimodal coupling data, different statistical distributions such as the generalized extreme value (GEV), Log-Pearson's Type III, and Gumbel distribution were used to assess the flood return period for various climate conditions. The delta change method (DCM) was utilized to estimate future peak flows, where the delta change factor (DCF) assisted in estimating different design flood events. SSP 3-7.0 had the highest projected streamflow out of all the projections along with final processing results from Hec-GeoRAS which was processed into HEC-RAS model to generate flood hazard maps and flood inundation maps. The future flow was then used to estimate and project the future floods flow. The results from the calibration and validation revealed good simulation of the river Chenab streamflow values of HEC-RAS. The results indicate that flood inundation extent will increase in the future, suggesting a higher flood hazard. This study emphasizes the significance of projecting future flood hazards and using predicted climate data to obtain crucial evidence for developing effective floodplain management strategies.