Modelling of Flash Flood Mitigation through Flow Diversion: A Case Study of the Teesta River Basin, Bangladesh

Abstract

Flooding remains one of the most devastating natural hazards in Bangladesh, particularly in the northern riverine regions, where transboundary water-management issues exacerbate vulnerability. This study presents a proof-of-concept computational fluid dynamics (CFD) analysis conducted using SOLIDWORKS to model a novel geometric flow-diversion structure for flash-flood mitigation. It evaluates a proof-of-concept hydraulic model designed to mitigate flash-flood damage through flow diversion and velocity reduction in the Teesta River basin. The computational domain for this initial study measures 8.0 m × 2.5 m × 2.0 m. The proposed Flood Flow Mitigation Model employs strategically positioned geometric obstructions to create a diverging-flow effect, resulting in energy dissipation and flow deceleration. The SOLIDWORKS CFD analysis indicates that the system achieves a 20% velocity reduction under baseline conditions (inflow velocity: 1.000 m/s; outflow velocity: 0.800 m/s). Theoretical performance scalability is suggested to be proportional to the system dimensions, although this relationship requires further validation through physical experimentation and parametric testing. The model may address challenges including reduced sediment transport, bank-erosion control, and the provision of additional warning time for vulnerable communities; however, these potential benefits require further investigation through unsteady-flow analysis and field validation. This study contributes to research on flash-flood mitigation in developing countries by presenting a potentially cost-effective and technically feasible approach to flood-risk reduction, subject to detailed economic analysis and site-specific validation. The findings may inform flood-management policy in Bangladesh and other flood-prone regions with similar topographic and hydrological characteristics.