Flood hazard sensitivity to storm surge-high water concurrence in a hyper-tidal estuary

A web-based, geospatial decision support tool (DST) is described here as a means to assess potential flooding for low-lying coastal and estuarine areas. These areas are at risk from inundation in the future as a result of sea-level rise, coastal storms and high river flow. Flooding assessments use a 2D inundation model, LISFLOOD-FP, and utilize open source GIS. The DST enables users to explore the depth and extent of potential flooding from combinations of sea-level rise and storm surges at sites of nuclear energy assets in the Severn Estuary, South West England. LISFLOOD-FP uses a standard model setup and is forced at the boundaries using tide gauge data. Delft3D is used to assess spatial variability in extreme water levels in the Severn Estuary, with the aim of reducing uncertainty associated with the timing a storm relative to tidal high water in the boundary conditions for the DST.