Application of TELEMAC-2D and SISYPHE to complex estuarine regions to inform future management decisions

Complex, high resolution, finite-element TELEMAC-2D grids have been developed to simulate ocean/fluvial interaction in three shallow, intensively managed Welsh estuaries. In each case, important ecosystems and developed areas are exposed to flooding from both tidal and fluvial events. Of particular concern is how the estuaries will be affected by future sea-level rise due to climate change, and how best to manage the estuaries in the future. Each grid has been generated using BlueKenue and comprises several sub-grids to resolve important aspects of the estuary, such as river channels and flood embankments. Accurate representation of these features is paramount to flood risk modelling. A selection of present-day mean and extreme hydrodynamic/fluvial scenarios has been simulated, as well as future climate change scenarios. These simulations have highlighted the need for local management so that coastal flooding and morphological change are minimised, whilst preserving important ecosystems such as protected salt marshes and peat bogs. Alterations were made to the grids in order to address possible management options such as coastal realignment. In this way, key implications for flood risk, sediment transport and morphological change can be predicted which will aid management decisions.