21 Aug 2017

Protecting beaches from erosion through shoreline modelling

Long-term predictions of shoreline evolution possible with MIKE 21 Shoreline Morphology software

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.  

To gain greater insight into the nature of the erosion and the effectiveness of possible management options, DHI’s local office in Australia was commissioned by the Department of Environment, Water and Natural Resources (DEWNR) to undertake a numerical modelling of the coastal processes at West Beach. 

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

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.

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 programme, as will possible future coastal management options briefly discussed at the workshop.
DEWNR is pleased with the progress to date on the modelling study and is confident that our models will provide useful information to guide the management of the West Beach section of Adelaide’s coast.  

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Contact us for more information on predicting long-term shoreline movements.