GIS Modelling of Sea-Level Rise Induced Shoreline Changes Inside Coastal Re-Rntrants – Two Examples from Southeastern Australia

Shoreline recession as a result of rising sea level has been recognised as a potential near-future hazard by a number of countries. However, the collection of high spatial resolution data, in particular elevation data, is often too costly and time consuming to be applied routinely for a detailed assessment of the potential physical and economic impacts of this hazard. Based on work undertaken for the Dutch Wadden Sea, a GIS-based coastal-behaviour model has been developed to formulate simple algorithms for simulating the potential physical impacts of rising sea level on the coastal environment, focussing here on coastal re-entrants. The GIS model developed is suitable for providing first estimates of potential shoreline change, based on readily available information. To enhance the suitability of such initial assessment, the GIS model output, that is the rate of shoreline change, has been analysed in greater detail using a spreadsheet-based hazard probability model. The advantage of using a combination of both models is a rapid assessment of the probability of shoreline changes, instead of a single impact zone, as modelled with the GIS. The hazard probability rates received from the spreadsheet model are returned to the GIS to be displayed as a grading of risk instead of a single impact zone. The model introduced in this paper has been applied to two field sites in southeastern Australia to model regional variations in shoreline response to rising sea level. Copyright Kluwer Academic Publishers 2004