A Riverbank Erosion Early Warning System: A Case Study of the Braided Brahmaputra-Jamuna River

Shampa Shampa^1*Hussain Muhammad Muktadir¹Israt Jahan Nijum¹Md. Majurul Hussain¹Anup Bhowmik²Nazmul Islam Ananto²Fardin Anam Aungon²Showvik Biswas²Mohammad Muddassir Islam¹

• ¹Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
• ²Bangladesh University of Engineering and Technology, Dhaka, Dhaka, Bangladesh

Braided rivers are distinguished by numerous bars and channels, along with their regular alterations. This unique character of braided rivers induces bank adjustment through erosion or accretion, and when erosion occurs in populated regions, it results in significant disasters. To address this calamity, we propose an early erosion system called EWS-RE. Here the warning for riverbank erosion was issued utilizing the numerical simulations of a 2D hydro-morphological model of the Brahmaputra-Jamuna. We integrated the GloFAS seasonal forecasts with over sixty years of hydraulic river forcing them to establish the boundary conditions for the forecast model. The high-resolution braided river bathymetry was produced utilizing a modified passive bathymetry technique utilizing satellite imagery and limited measured cross-sectional data. The detailed model results and riverbank erosion were juxtaposed with the actual conditions of the year 2019. The spatial erosion accuracy was assessed at 88%, with a sensitivity of 88%, and falls within a 95% confidence interval. The field testing of the warning was performed for the year 2023 and demonstrated an accuracy of 70% along the river. We expect that our stated framework will help to alleviate the impacts of riverbank erosion disasters through early warning.