Modelling Hydrodynamic Impacts of Sea-Level Rise on Wave-Dominated Australian Estuaries with Differing Geomorphology

Abstract

Sea-level rise (SLR) will affect the hydrodynamics and flooding characteristics of estuaries which are a function of the geomorphology of particular estuarine systems. This study presents a numerical modelling of coastal flooding due to drivers such as spring-tides, storm surges and river inflows and examines how these will change under sea-level increases of 0.4 m and 0.9 m for two estuaries that are at different geomorphological evolutionary stages of infill. Our results demonstrate that estuarine response to SLR varies between different types of estuaries, and detailed modelling is necessary to understand the nature and extent of inundation in response to SLR. Comparison of modelling results indicates that floodplain elevation is fundamental in order to identify the most vulnerable systems and estimate how inundation extents and depths may change in the future. Floodplains in mature estuarine systems may drown and experience a considerable increase in inundation depths once a certain threshold in elevation has been exceeded. By contrast, immature estuarine systems may be subject to increases in relative inundation extent and substantial changes in hydrodynamics such as tidal range and current velocity. The unique nature of estuaries does not allow for generalisations; however, classifications of estuarine geomorphology could indicate how certain types of estuary may respond to SLR.

Mapping Impact of Tidal Flooding on Solar Salt Farming in Northern Java using a Hydrodynamic Model

“…However, it is the hydrodynamics of the tide that is responsible for the size of the tide range, high and low waters momentum, and tidal characteristic, as well as the speed and timing of the tidal current [33]. An integrated approach considering both aspects is recommended, particularly for smaller areas and in cases where details are essential [29,34,35]. In this study, a simulation of the tidal flooding on salt production area is presented.…”

“…This approach assumes areas lower than a particular elevation to be inundated utilizing digital elevation model (DEM) and geographic information system (GIS) [27,28]. Geophysical processes including bottom friction or motion transfer are not considered in these particular models [29]. Ultimately, the uncertain behavior of the coastal system during a coastal flooding event is still a challenge in this model [30].…”

Climate Change, Coasts and Coastal Risk

“…The papers of Watson [1], Helman & Tomlinson [2], Bigalbal et al [3], Bamunawala et al [4] and Kumbier et al [5] aim to improve our understanding of the links between climate change, coastal forcing (SLR, storm surge, waves) and coastline change. Watson [1] and Helman & Tomlinson [2] look backward and discuss observed climate change impacts.…”

“…Watson [1] and Helman & Tomlinson [2] look backward and discuss observed climate change impacts. Bigalbal et al [3], Bamunawala et al [4] and Kumbier et al [5] look forward and discuss methods for modelling the impacts of climate change, presenting applications from around the world.…”

“…The contributions of Bigalbal et al [3], Bamunawala et al [4] and Kumbier et al [5] show that the impacts of climate change on coastal forcing and coastal change depend strongly on local circumstances, and that estimating these impacts requires physics-based extrapolations into an uncertain future. Bigalbal et al [3] examine the potential impacts of sea level rise and marsh migration on the hydrodynamics and wave conditions within four natural protected areas of the Chesapeake Bay during storm surge events.…”