DHI: Protecting South Australia Beaches from Erosion

The Department of Environment, Water and Natural Resources (DEWNR) recently commissioned DHI Australia to undertake a numerical modelling of the coastal processes at West Beach, aiming to gain greater insight into the nature of the erosion and the effectiveness of possible management options.

West Beach, a seaside suburb of South Australia, has been a particularly erosive part of the Adelaide coast for decades. This erosion has been managed with regular beach replenishment via a backpass pipeline.

A workshop was held recently to discuss the analysis of the survey together with other data and the preliminary modelling that has been completed to date, DHI said.

The modelling analysis involved the development of a comprehensive coupled MIKE 21 HD and SW model of the Gulf St Vincent to enable an eight-year hindcast of waves, water levels and currents to be developed for the study area.

Enabling long-term predictions of shoreline evolution 

The detailed hindcast will be used to drive a MIKE 21 Shoreline Morphological (SM) model of the study area.

“An advanced new model for studying coastal morphology, MIKE 21 SM enables robust long-term predictions of shoreline evolution for complex shorelines, where inherent two-dimensional features of the bathymetry and coastal structures, significantly influence the shorelines evolution,” DHI said.

An initial assessment of beach volumes indicates that a significant amount of sand is being transported by natural processes from West Beach to Henley Beach. This will be investigated further as part of the modelling program, said DHI.

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