New technology to shore up Limestone Coast beaches

COASTAL BENEFIT: Grant District mayor Richard Sage says the acquisition of two wave buoys will help council mitigate future coastal issues and provide ocean users with increased safety.

By Raquel Mustillo

COASTAL homeowners, fishers and marine recreation activities will benefit from new technology to measure ocean waves and currents soon to be deployed in Robe and Port MacDonnell.

Grant District Council has allocated $20,000 towards two wave buoys – which collect crucial data on wave height, direction, period and surface current speed – as part of a collaborative project with Robe District Council and Flinders University.



The coastal monitoring system is expected to provide council with a record of storms, significant wave heights, a better understanding of seasonal and storm conditions and a record of climate driven chances across the Limestone Coast. 



Robe District Council chief executive James Holyman said a lack of Limestone Coast-specific data prompted the need for a monitoring system to identify erosion risks and prepare for the impact.

Mr Holyman said Robe council had budgeted $50,000 for the project, with the town’s professional fishermen association providing in-kind funding for the deployment and maintenance of the buoys.

“When I first came to Robe, I got a group of experts in a room to talk about coastal dynamics so council could make wise decisions about erosion and in the longer term, sea level rising and potential inundation,” he said.



“When I asked the experts about the research and understanding coastlines, they said there was a gap in data, particularly in South Australia.


“The nearest tidal gage to Robe is at Kangaroo Island and the nearest wave point is probably up there so, so the information gathered there is not very useful to us in understanding the size and types of waves here and how it impacts and erodes our limestone cliffs.


“In conversations to the community about the coastline, erosion and the way forward, I wanted them to know we have made wise decisions based on evidence, which has driven this process”.

Mr Holyman said council had been in discussions with Flinders University for nine months about the proposal, with researchers planning to put in a grant proposal to the Australian Research Council this month.



He said data collected from the buoys will benefit the region’s coastal councils, as well as provide essential information for organisations across the nation.

“Wherever you interfere in the coastal system such as putting in a breakwater or putting a groyne in to stop erosion, there is an equal and opposition reaction elsewhere because the ocean is a closed system,” Mr Holyman said.



“That is why this research is so critical because if you were to put in a temporary reef or a permanent reef to protect a beach, it will help you understand what this might mean for the rest of the system.


“We intend to build models about wave movement, wave pattern and erosion on the shoreline and if people collect their own data, they can use the models to understand their own coastline.



“If you have the models, you will be able to determine whether you can put breakwaters or reefs in a location or if you can’t because it will create another problem. 


“At the moment, we don’t have the data to do that so if someone was to say they wanted to build a wall because their house is at risk, I could say it would not be a wise thing but we would be arguing at a fairly high level without knowing what the true consequences are.” 



Grant District mayor Richard Sage said the information will help council understand the dynamics of the coast and guide staff in managing coastal adaptation.



“The wave buoys will help us get some data about what is going on along the coast in terms of coastal erosion, storm surges and what wave heights are doing,” he said.

“We hope we can do some desktop studies and see what we are able to do to mitigate the damage that has happened in past storm events. 



“Unfortunately it will happen in the future, but the buoys will help us make the best of a bad situation.

“The real time data, seeing wave actions and temperature rises in the water will help us look forward and try to protect assets in the future.”



Mr Sage said as well as increasing knowledge and understanding of ocean processes to mitigate erosion, the buoys will provide commercial and recreational anglers with fisher-friendly accurate information to help better prepare for trips and make strategic decisions while on the water. 


He said the buoys will also provide sailers, surfers and other recreational users with accurate wave-forecasting information.


“We want amateur and professional fishermen to be able to lock into the wave buoys so they are able to get real data and see what is happening with the sea and water temperature,” he said.



“As well as helping them be safer on the water, it will also be handy for the fishermen as far as ongoing research into crayfish.



“We are pretty close to the shelf which is only 30-odd kilometres off the beach which goes into 500m of water and with the buoys we will be able to look into water temperatures and see when the upwelling happens and that is for the spawning of the crayfish.



“The angler club have always wanted a camera set up so you can see what the ocean is doing.



“It would be nice to have one here and at Carpenter Rocks so at any given time, that data is available for everybody so you can see the waves just by looking through the camera and make a decision on whether they want to go to the beach.”