Exploring the Flooding Under Damming Condition in Punarbhaba River of India and Bangladesh

Abstract

AbstractThe flooding in India and Bangladesh causes enormous damage to life, property, and infrastructure loss. The present study, Punarbhaba River, a flood-prone transboundary river of India and Bangladesh, has witnessed many floods since historical times. It needs to be monitored closely. Therefore, we explored the flooding conditions and their effect on river ecology with management in the present study. The present study analyzed the flood condition using flood frequency, basic regional hydrology analysis, and probability analysis. We also reconstructed flooding scenarios using a 2-D hydraulic model at different flood return periods. The wetland transformation has been explored under the reconstructed flooding scenarios. The wetland habitat health was also modeled under different flood scenarios using logistic regression. We proposed flood management plans with the help of a random forest-based flood susceptibility model. Also, we proposed a wetland management plan in floodplain areas with a nature-based solution technique. The average water level (W.L.) during pre- and post-monsoon was 52% and 32%, respectively, but the flow level increased to 3% in postdam periods. The study area witnessed 18% more sudden flooding. Results showed that 4% and 5.1% wetland areas were predicted to be very high and high vulnerable zones during pre-dam conditions, while these have been increased to 34% (very high) and 20% (high) during postdam phase. Findings showed that the flood susceptibility model predicted 11.65% of the area as very high flood susceptible zones, which must be monitored closely. This study will provide a comprehensive foundation for flood management.KeywordsHydrological alterationDamming conditionWetland habitat healthNature based solutionRemote sensingMachine learning