Australian beaches are arguably the best in the world, but their existence has long been under threat from erosion. Artificial structures are proving to be a game-changer in efforts to safeguard our coasts. They're helping mangroves grow, prevent beaches from receding and boost aquatic life.
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00:00 I've lived on the Bellarine Peninsula for just over 30 years and have noticed considerable
00:07 change. We've seen serious coastal recession over the last few years.
00:11 This strip of beach on Victoria's Bellarine Peninsula is only here thanks to some engineering
00:17 intervention. The beach had shrunk by 30 metres in just two years due to erosion.
00:24 So it was time to act. We really needed to do something.
00:27 The answer was this. Rambler's Reef. It's made up of steel cages filled with rocks and
00:33 shells. It was installed 100 metres offshore five years ago to help the beach grow back
00:40 and protect homes. The reef acts to reduce wave height and therefore
00:45 reducing wave energy. We've seen substantial broadening of the beach to the order of about
00:51 40 metres. Eventually the steel will corrode leaving
00:55 a natural shelf colonised with seaweed and shellfish. The project has been so successful
01:01 that the council has installed a second artificial reef a few kilometres away.
01:08 The Dell Eco-Reef in Clifton Springs is not only a coastal shield, it's also a haven for
01:14 marine life. The undulating modules were cast in a lab.
01:19 Since this reef was installed a year ago, erosion has stopped and a vast seagrass field
01:25 has grown, helping trap carbon. Coastlines are in a constant state of flux,
01:31 with the movement of water and wind hitting the shore, stealing away sand and sediment.
01:37 Techniques like building rock groins or re-nourishing beaches with sand from quarries are used on
01:43 some foreshores to help sand accumulate, but they're not great options.
01:48 It starts to produce a cascade of effects of transfer and an erosion problem from one
01:53 spot to another. The threat of climate change accelerating
01:57 coastal erosion means these sorts of innovative structures are becoming increasingly necessary
02:02 to create more resilient shorelines and to make sure that our beaches are still here
02:08 for generations to come. Here on the other end of Victorious Coast,
02:14 3D printed lattices are being used to help mangroves to flourish. The lattices slow water
02:20 flow and encourage soil accumulation, acting as a natural barrier against erosion.
02:26 When I was growing up, you used to be able to roll in it, it was mountains of seagrass
02:29 all the way around the coast and that was your natural buffer.
02:32 We're hoping that we're seeing higher seed retention and seedling survival and growth
02:37 within the lattices compared to without. The lattices are made from potato starch and
02:42 will biodegrade once the mangroves have established themselves. The plants help to maintain shorelines,
02:48 absorb carbon and are vital habitats for animals and marine life.
02:53 The lattices are already in one area of Port Phillip Bay and now in Western Port as well.
02:59 And if successful, they could be used in coastal wetlands across Australia as an eco-friendly
03:05 alternative to the usually plastic or concrete solutions.
03:10 And they also protect our coastlines from storm surges and flooding.
03:14 But with nearly 90% of Australians living within 50km of the coast, preserving beaches
03:20 into the future will be critical.
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