Simulating microplastic-vegetation interactions in the SERGHEI framework

The presence of microplastics in aquatic environments has increased over the past years, and reducing their concentration remains a significant challenge due to their negative impacts on biota. Aquatic vegetation can act as a natural mitigation measure by retaining microplastics and reducing their transport. Numerical tools that predict the evolution of flow and microplastic transport in the presence of vegetation can be valuable for identifying where and when vegetation is most effective at retaining particles. This work presents a coupled Eulerian-Lagrangian model to simulate shallow water flows and microplastic transport, incorporating vegetation as an additional drag force in the flow equations and as a probabilistic capture mechanism. Analytical cases are simulated to evaluate model performance, aiming to extend it to large-scale simulations while assessing accuracy and computational cost. The results provide valuable insights into microplastic–vegetation interactions and demonstrate that the proposed approach constitutes a scalable and computationally efficient framework for simulating such processes in shallow water systems.