Trang Minh Duong

A QUALITATIVE ASSESSMENT OF CLIMATE CHANGE IMPACTS ON THE STABILITY OF SMALL TIDAL INLETS VIA SCHEMATISED NUMERICAL MODELLING

Tidal inlets are of great societal importance and are also the most morphologically dynamic regions in the coastal zone. Therefore, they are of great scientific interest. Their behaviour is governed by the delicate balance of oceanic processes such as tides, waves and mean sea level (MSL), and fluvial/estuarine processes such as riverflow. All of these processes can be significantly affected by climate change (CC) processes, which may result in negative physical impacts such as inlet closure/relocation, creation of new inlets, erosion of the coast adjacent to the inlet etc. Although CC impacts on some large tidal inlets (e.g. Wadden Sea inlets) have received some attention recently, the potential CC impacts on small tidal inlets (STIs) remain virtually unknown to date. Furthermore, whether currently available predictive tools are capable of simulating CC impacts on these systems also remains unknown. These knowledge gaps are a serious threat to effective adaptation to CC in STI environments. Just, this study attempts to investigate the potential range of CC impacts on the stability (i.e. closed/open state and locational stability) of STIs via the application of a sophisticated process based morphodynamic model (Delft3D) to strategically selected schematised inlet morphologies and forcing conditions. Results indicate that CC driven variations in system forcing are likely have profound impacts on inlet stability and also show that a process based coastal morphodynamic model (eg. Delft3D) is suitable for investigating potential CC impacts at small tidal inlets.

Climate Change Impacts on the Stability of Small Tidal Inlets: A numerical modelling study using the Realistic Analogue approach

Tidal inlets are of great societal importance as they are often associated with ports and harbours, industry, tourism, recreation and prime waterfront real estate. Their behaviour is governed by the delicate balance of oceanic processes (tides, waves and mean sea level), and fluvial/estuarine processes (riverflow and heat fluxes), all of which can be significantly affected by climate change (CC) processes. This study investigates the potential range of CC impacts on the stability (closed/open state and locational stability) via the application of a sophisticated process based morphodynamic model (Delft3D) to strategically selected schematized inlet morphologies and forcing conditions. Results show that, under worst case scenario conditions, the integrated effect of climate change driven increase in mean sea level, wave height and wave angle may significantly change inlet stability condition.

Sediment dynamics of Negombo Lagoon Ooutlet, Sri Lanka.

This paper presents a 2DH modelling approach used to investigate sediment dynamics and potential morphological changes of the Negombo lagoon outlet, Sri Lanka. Schematised wave, wind and river-inflow parameters were imposed representing the present day forcing scenario. The model was initially calibrated against the measured water level and velocity data, and then implemented to observe sediment dynamics and morphodynamics. Northward alongshore transport in this area changes to the west-east orientation at the outlet and is interrupted by the lagoon sediment export. Channels at the lagoon end have different transport capacities. Residual transport showed a sediment exporting system in the lagoon. One-year period of morphological evolution suggested that the narrow connecting channel between the lagoon and the sea experiences erosion and sedimentation in front of the lagoon entrance. Also, erosion at the apex of the western headland provides sediment to south and north therein.