Foreshore erosion is an increasing problem, affecting, apart from urban foreshores, regional infrastructure, tourism and the environment.
And while it’s a problem engineers and ecologists have been battling for centuries, rising sea levels have turned the tide back in favour of the forces of nature.
But a new study off the what’s known as the Limestone Coast, off Robe in South Australia’s southeast, seeks to help the historic fishing port regain some of that lost ground.
“The South Australian coast faces some of the largest swells in the world produced in the Southern Ocean,” says Flinders University PhD candidate Charlotte Uphues. “This highly energetic environment causes significant coastal sand movement, often resulting in coastal erosion.”
For Robe, that means having to invest $500,000 each year in sand replacement projects to keep its beaches in a healthy state.
Flinders Uni Beach and Dune Systems (BEADS) Lab is extending a network of wave buoys that currently monitors Adelaide’s metropolitan coast and Kangaroo Island, to the Limestone Coast. This will provide real-time data to better understand changing currents, waveforms and coastal processes.
Over the past century, global temperatures have climbed an average 1C. And since 1880, according to the US National Oceanic and Atmospheric Administration (NOAA), melting land-based glaciers have resulted in a sea level rise of between 21-24cm.
It’s causing previously observed natural processes to change their balance.
The two buoys were positioned 8km and 1.5km off Robe’s iconic inner bay beach.
This positions the buoys to monitor how waves change as they transition from offshore depths to near-shore coastal conditions by capturing data such as height, period, direction, wind speed, sea surface temperature and barometric pressure.
Uphues is using the observations to refine models of the local hydrodynamic processes to understand and predict future changes in the coastline.
It’s also helping inform the coastal harbour’s daily operations, including dredging operations, navigation and sea condition reporting for fishers. The information is publicly available on the www.sawaves.org website.
“For the Robe region, and indeed for much of South Australia, there has been a significant gap in wave information available to researchers, managers, developers, and policymakers because the nearest wave buoys are more than 200 km away,” says Flinders University Associate Professor Graziela Miot da Silva.
The buoy project is a collaboration with the South Australian Research and Development Institute (SARDI), Primary Industries and Regions SA.
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