Breaching of Coastal Barriers under Extreme Storm Surges and Implications for Groundwater Contamination

Abstract

Coastal floods induced by a coastal barrier breaching under extreme storm surges represent a significant humanitarian, socioeconomic and ecological hazard. Moreover, it is a multiscale problem governed by complex interactions between a variety of hydrodynamic and sediment-related processes at different spatiotemporal scales. With global warming and expected climate change, many coastal systems may experience accelerated coastal erosion, coastal barrier breaching, coastal flooding and subsequent seawater intrusion into fresh groundwater. However, the current models of breaching-induced coastal floods and subsequent saltwater intrusion are mainly based on modelling each of these processes separately, which often leads to unreliable simulations because the mutual interactions among these naturally successive processes are ignored. Therefore, to consider such interactions, this study aims at exploring the possibility to simulate breaching, flooding and saltwater intrusion in a single model system in order to reliably draw the implications of coastal floods for groundwater contamination. For this purpose, this study aims first at selecting a suitable breaching model that can properly calculate inland discharges through breaching induced inlets. Second, the study attempts to couple the selected breaching model with suitable inundation and saltwater intrusion models in order to simulate successively the breaching-induced inundation and the subsequent saltwater intrusion.