Coupled effects of wind shear and bed absorption on sediment transport in wetland

Wetlands play a vital role in sustaining ecosystems, supporting biodiversity, and controlling environmental degradation. Sedimentation in wetlands has emerged as a critical research area due to its relevance in flood management, water purification, and geophysical applications. Despite its importance, the combined effects of wind shear and bed absorption on sediment transport remain underexplored. This study investigates sediment removal efficiency in wetland flow influenced by wind shear, absorbent beds, and particle settling. The time-dependent convection-diffusion equation is solved using a hybrid approach, combining Aris's method of integral moments with a finite difference implicit scheme. Analytical expressions for two-dimensional spatial concentration distributions are derived via Gill's series expansion. Key parameters, including wind direction (W), relative wind strength ( E r ), bed absorption coefficient ( β ), vegetation parameter ( α ), and settling velocity ( ω ), are analyzed to determine their impact on dispersion characteristics like the dispersion coefficient, concentration distribution, skewness, and kurtosis. Results show that wind shear enhances sediment dispersion when aligned with the flow ( W = + 1 ) but induces backflow and reduces dispersion within a certain wind strength range when opposing it ( W = − 1 ). Bed absorption accelerates stabilization by trapping particles, limiting their dispersion capacity. Settling velocity further influences dispersion by reducing the suspension of the particles, with higher ω accelerating stabilization but suppressing long-term dispersion. Dense vegetation reduces wind-induced variations, improving flow stability by dampening momentum transfer. This study provides new insights into coupled wind-absorbent bed-settling velocity interactions, offering a framework for optimizing wetland design, pollutant removal, and environmental sustainability. This proposed model can be applied to optimize wetland restoration strategies, enhance sediment management in aquatic ecosystems, and improve pollutant filtration efficiency in natural and engineered water systems.