Modelling estuarine wetlands and their role as nature-based solutions: a review

Estuaries are important ecosystems that provide multiple services, support biodiversity, and protect inland areas. Yet, these environments are increasingly threatened by urban expansion, anthropogenic activities, and climate change. One emerging alternative for enhancing resilience in estuaries is the conservation or implementation of vegetated areas/ wetlands that function as Nature-based Solutions (NbS). Hydrodynamic models are valuable tools for understanding and predicting coastal dynamics, and for evaluating the impacts of NbS and other coastal interventions. This study systematically reviews research on the application of hydrodynamic modelling tools to assess the dynamics and the effects of different types of estuarine wetlands, including mangroves and salt marshes. Relatively few studies have modelled the implementation of wetlands as NbS. Most of the studies considered in this extensive review are focused on modelling existing vegetated areas, providing a strong foundation for mechanistic understanding, and for validating modelling approaches that can inform and guide future NbS projects. Results show that numerical models can effectively simulate estuarine wetlands, though there are still challenges related to data resolution, vegetation parameterization, and computational efficiency. Numerical models also help to understand key ecosystem services provided by wetlands, including water quality improvement and coastal protection against extreme events or climate change scenarios. However, the efficiency in delivering those services is influenced by vegetation health and soil stability, which are affected by multiple factors. Therefore, local and detailed site-specific knowledge should be taken into consideration when applying numerical models to assess the benefits of vegetation in estuarine environments.