The other day someone said to me that I can’t go five seconds without talking about coastal erosion. While that’s not true (I think it was a subtle hint they find me boring), coastal erosion is definitely worth talking about at the moment.
We haven’t seen erosion like this on some of our beaches since the mid-1970s – it’s historic! Dunes are being eaten into, long-forgotten rocks are being exposed, and structures built too close to the ocean are at risk. It’s a big deal and all because we’ve had big swell event after big swell event for ages thanks to back-to-back La Nina events, with perhaps a third coming!
People who grew up in the 70s talk about how bad the beaches were with logs and debris everywhere, not unlike what we’re seeing now. In the coastal world everyone talks about the storms of 1974. So what exactly was going on back then?
The last time a triple La Nina occurred was …you guessed it … 1974. That year there were three major storm wave events between February and June, all of which had wave heights in excess of 5m.
The most damaging was the ‘Sygna’ storm in May, when an East Coast Low (maybe we should start calling them Cyclones, which is what they are) with wind gusts of 165km/hr and 9m+ waves, drove the freighter Sygna onto Stockton Beach near Newcastle. That storm is considered to be one of the most severe storms to hit our coast since European settlement. Locally it also marked the end of the beach shacks at Coalcliff. I’d be interested in hearing more about
the impacts along our coast, so please contact me!
The storms of 1974 were a real wake-up call and the catalyst that spurred governments into trying to understand the characteristics and behaviour of waves, beaches and dunes. They were the motivation for dune revegetation programs throughout NSW and the installation of offshore wave rider buoys to monitor wave conditions along the entire NSW coast. It was really the birth of coastal management in Australia.
While we understand how beaches respond to waves much better today and can even predict the amount of shoreline erosion that will occur in advance, we still can’t stop it. History is repeating itself with La Ninas, lots of big storm waves in a short period of time, freighters coming ashore
(the Pasha Bulker in 2006 and the bulk carrier Portland Bay’s narrow miss last month off the Royal National Park), and lots of erosion.
One thing to remember is that all beaches respond differently and it’s not all bad news. Erosion is always worse on small pocket beaches, near inlets, and in front of, and alongside, seawalls and concrete structures. In time the beaches will recover – they always do.
Share stories of how the 1974 storms impacted our coast. Email rbrander@unsw.edu.au
Visit www.scienceofthesurf.com
