Erosion expected in upcoming easterly swell
"Looking up and down the East Coast, there are currently a lot of beaches that are exposed to erosion," says Professor Andy Short, the Director of Sydney University's Coastal Studies Unit.
"For many months we've had little else but low energy south swells. There's been nothing significant from either the east or north."
"The result," explains Andy, "is that many east facing beaches have rotated to the north."
By this he means the sand, rather than being equally distributed, is very wide at the northern ends and relatively narrow at the southern ends (see image of Narrabeen below), and it's this distribution that has him concerned.
As I type, an easterly trough is setting up camp off Australia's East Coast poised to blow east-northeast winds from Noosa to Eden and kick up a swell from the same direction. While the surf won't get enormous, it's the longevity that has people such as Professor Andy Short worried.
With a stable Tasman high cradling the trough, the weather system will sit in place for at least five days, and there's potential for even more northeast swell to follow*.
Any beach exposed to the east or northeast is in for a hammering, particularly the southern ends, the same ends that are already narrow owing to a lack of sand nourishment.
In early December, Newcastle Council did their own sand nourishment at Stockton Beach, a stretch of coast that's been threatened by severe erosion for the last five years. The council trucked in 5,500 tonnes of sand at a cost of $350,000, dumping it just north of the caravan park. Lord Mayor Nuatali Nelmes said it was "only a short-term response" and she wasn't wrong.
"It lasted about a month," said Stockton local Simon Jones. "It's all moved offshore now. The beach down there is the same as it was."
Fortunately, it was only the first of a staged campaign, though the second stage, involving more sand nourishment near the Surf Club, is subject to further funding and approvals by the state government. A council spokesperson couldn't tell Swellnet when the second stage of nourishment may occur.
More pressing is how Stockton will fare in the imminent swell. "It's not great down there," says Simon Jones. "You could say that it's better than this time last year, but considering what we're facing we may be in trouble."
And it's not just Stockton, other noted erosion zones such as Collaroy, Old Bar on the Mid North Coast, and Belongil north of Byron, could all face trouble in the coming week.
Professor Andy Short is hoping the relevant local councils have used the downtime wisely. "They've had a long lead time to prepare their contingencies," says Andy. "They should all be prepared for what's to come."
We'll find out if that's true sometime next week.
*Current GFS forecast has a cyclone moving south and becoming extratropical as it traverses the entire surfable stretch of the East Coast. However, that scenario is a week out during a dynamic period, which reduces the odds. We'll update this event in the comments below.