Assessing climate change impacts on flood inundation patterns: a study of northern Pakistan

ABSTRACT This study employs ArcSWAT for hydrological modeling to project future streamflows for the SSP2-4.5 and SSP5-8.5 scenarios. Subsequently, HEC-RAS is utilized to generate inundation maps for multiple return periods. The study anticipates that climate change, particularly changes in precipitation and temperature patterns, will lead to a significant increase in future flood magnitudes. For a 100-year return period in the near future, the projected flood value is 5,337 m3/s under the SSP2-4.5 scenario and 6,777 m3/s under the SSP5-8.5 scenario. Similarly, flood values for other return periods (5, 50, 500, and 1,000 years) are projected to be 3,628, 4,972, 6,161, and 6,510 m3/s under the SSP2-4.5 scenario, and 4,047, 6,165, 8,208, and 8,835 m3/s under the SSP5-8.5 scenario for near future. Future flood inundation analysis reveals critical flood-prone areas requiring targeted protection and mitigation strategies to ensure safety. The results also show that water depth has increased from 31 m historically to 37 m in 2022, with future projections reaching 40 and 48 m under SSP2-4.5 and SSP5-8.5 scenarios, respectively.