Analysis of flood and channel dynamics adversity in the Upper Beas Basin during 9-11 July 2023, Himachal Pradesh.

The Himalayan region has experienced several floods in the last two decades, due to extreme rainfall episodes often linked with the climatic dynamics and anthropogenic changes. The large-scale changes due to anthropogenic activities in the catchment area have affected the water-balance components through the modified input and output parameters; as a result, peak flow was observed in the rivers, causing severe floods and changes in the channel morphology. The main aim of the present research is flood frequency analysis, mapping channel dynamics and their relationship with flood damages in the Upper Beas catchment. The rainfall data were procured from the Indian Meteorological Department (IMD), and processed data of satellite meteorology were used for the flood frequency analysis and flood simulation in HEC-RAS software. Landsat series satellite images were used to map the channel dynamics for the upper catchment area. The detailed field investigations were also carried out in the study area to collect data on flood levels at cross-sections, and bencharmaks to validate the simulated flood levels, and channel migration-associated flood damage at various locations, and affected communities. The result suggests that substantial damage occurred on July 9 th and 10 th , 2023, floods. The high-stage flow-induced channel dynamics cause bank erosion and slope failure, causing massive damage to houses, shops, hotels, road sections, bridges and other critical infrastructures. It was also assessed that the impact of the flood was not limited to the physical damages; it included loss of lives, injuries, mental trauma to the affected families, as well as loss of livelihoods in different forms. Despite government rescue and rehabilitation efforts, many victims felt helpless for months. The magnitude of the disaster necessitates long-term measures for effective flood management and a mitigation plan in the region.