Storm Erosion
Storms and flooding caused huge problems across eastern Australia last week. The damage was particularly bad along the coastline where many homes were badly damaged. Here's why.
From Queensland right down to Tasmania, Australia's eastern coast took a battering during these huge storms recently. Gardens and decks were pulled apart, houses were damaged beyond repair, even an in ground pool couldn't withstand the waves.
Big storms aren't rare in Australia. But this one seemed to do more damage along the coast than most others. So why was that? Well there were two major factors that combined to make this storm so destructive. The first was erosion.
REPORTER: And to show you how erosion works, I've set up a little experiment for you. In this tub we have sand and water just like you might see at the beach. And if I use this paddle and start making some waves, like the bigger waves weve seen along the east coast of Australia lately, you can see the shape of the beach starts to change. It even starts to crumble and fall apart.
Erosion is a natural force and it's something that's constantly happening all around us. It's part of a cycle that forms coasts, shapes mountain ranges, and digs out caves. But during unusually violent weather like this it happens much faster as lots of rain runs out to sea and waves pound hard against the beach.
But there was another factor that made the erosion much worse during this storm. The unfortunate timing of a king tide. Tides are the movement of the sea up and down each day. That happens mainly because of the moon. The moon's gravity pulls at the Earth, causing a small bulge in the water closest to where the moon is in the sky. As the Earth rotates, and the moon moves around it, that bulge moves around the Earth creating our high and low tides.
But every now and again the sun lines up with the moon and their gravity combines to pull on our oceans even more. That makes something known as a king tide. So if we pretend we've got a king tide in this tub.
REPORTER: With higher water waves can wash away beaches even faster.
Lately many scientists have been particularly worried about erosion along Australia's coastal areas. They say there are now more buildings along the beach but fewer plants holding the dunes together. That's why groups like this are stepping in to help secure our coastlines.
REPORTER: So on windy, rainy days like this, how can these little plants help hold the dunes together?
KID 1: Well I think once you've planted the plants, like after a while, the roots kind of sink in so if the wind's damaging the sand, the roots will kind of hold it together.
KID 2: Because the roots like here are holding all the dirt and sand together. And that will actually help our sand dunes when they hold it all together so it doesn't just erode away.
More vegetation is one thing but some researchers say we really need to stop building so close to the beach. Because big storms and the erosion that comes with them are a very natural part of life in Australia.
- Carl Smith | Reporter
- East Coast Floods: Behind the News | history
- Floods: Behind the News | history
- Floods: Behind the News | teacher
- Wild Weather: What caused the storms along Australia's east coast?: ABC News | weblink
- What is Coastal Erosion?: SES | weblink
- Australia:NSW | Map
- Storm Erosion | Worksheet
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