Sandy beach responses to sea level rise: comparison potential coastal inundation maps using static and numerical model for Ibai River, Malaysia case study

Abstract

Low-lying sandy beaches are vulnerable to coastal flooding due to rising sea levels and storm surges generated from offshore during the monsoon season. This study attempted to evaluate the overland flooding caused by sea level rise at Ibai river estuary. Static and numerical computer model approaches were used to determine the inland-flooded areas by the time horizon of the year 2100 with Representative Concentration Pathway (RCP) 8.5 scenario. Land elevation level, river and nearshore bathymetry, current flows and water level fluctuations are measured during the dry season. The predicted rate of low-lying coastal flooding induced by SLR is 2.5 times greater by using a static model compared to the numerical hydrodynamic model approach. In addition, the advantage of using the numerical model method able to help water managers in identifying flooding levels and tidal current speed magnitudes. This study helps increase the understanding of coastal management on potential coastal flood mapping related to sea level rise by providing tools and information on local coastal flood risks and making cost-effective mitigation decisions.