Resilient Riverbank Stabilization under Extreme Flood Events: Numerical Assessment and Optimization of a Hybrid Gabion–Geosynthetic System at the Gwagwalada River Confluence, Nigeria

This repository contains the full research manuscript titled “Resilient Riverbank Stabilization under Extreme Flood Events: Numerical Assessment and Optimization of a Hybrid Gabion–Geosynthetic System at the Gwagwalada River Confluence, Nigeria.” The study investigates sustainable and flood-resilient riverbank stabilization strategies for tropical river systems exposed to severe erosion and extreme hydrological conditions. The research focuses on the Gwagwalada River confluence in the Federal Capital Territory (FCT), Nigeria, where recurrent flooding events, including the 2020 extreme flood and the 2024–2025 intense rainfall episodes, have caused significant riverbank degradation, land loss, and infrastructure vulnerability. The study integrates hydrological analysis, hydraulic modelling, geotechnical investigation, and coupled hydro-geotechnical numerical simulations to evaluate the performance of a hybrid gabion–geosynthetic retaining system under varying flood scenarios. Advanced Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) approaches were employed to simulate turbulence, flow separation, shear stress distribution, soil–structure interaction, and bank deformation at the river confluence. Parametric analyses and optimization techniques, including Genetic Algorithms (GA), Response Surface Methodology (RSM), and Reliability-Based Design Optimization (RBDO), were applied to determine optimal configurations for gabion dimensions, geosynthetic reinforcement spacing, embedment depth, and slope stabilization performance. The study contributes to the development of resilient, cost-effective, and environmentally sustainable riverbank protection strategies for tropical and developing regions. It also provides practical design recommendations for engineers, researchers, planners, and policymakers involved in flood mitigation, river engineering, geotechnical engineering, and climate adaptation infrastructure. Keywords: Riverbank stabilization, gabion structures, geosynthetics, flood resilience, numerical modelling, CFD, FEM, hydro-geotechnical analysis, erosion control, tropical rivers, Gwagwalada River, Nigeria, climate change adaptation, river engineering, optimization.