Modelling biophysical Interactions in coastal wetlands to assess resilience to sea-level rise

Assessment of coastal wetland resilience under rising sea levels using models is challenging due to uncertainties in processes and external drivers. In addition, a number of assumptions and simplifications are required in order to be able to carry out long-term complex simulations that include processes over a wide range of time and spatial scales. Some of those simplifications can have important implications for the assessment of wetland resilience. In this contribution we look at a number of simplifications typically used in coastal wetland evolution models, and we try to quantify their effects on the results. We include simplifications related to hydrodynamics, sediment transport and vegetation dynamics focusing on issues of process description, process interactions and spatial and temporal discretisation. We pay special attention to the identification of methods that include a level of simplification that allows for efficient computation with acceptable margins of error. We apply our model to a number of coastal wetlands worldwide with a variety of settings in terms of vegetation, tidal conditions, sediment load and find that accelerated sea-level rise towards the end of the century will greatly compromise wetland resilience.