A SIMPLE rock wall constructed as an experiment has produced amazing results in preventing further leakage into the sea of a disused Port Fairy rubbish tip.
It withstood the battering from huge storm swells whipped up by gale-force winds on June 24 and stopped fierce erosion of the dune which acts as a fragile barrier to old rubbish piles.
In fact, the 200-metre wall built with local bluestone boulders produced a metre-high build-up of the beach level, according to monitoring data collected on Sunday.
“The results are phenomenal — no one expected it to work so well,” said Moyne Shire engineer Ebony Perrin, who heads an environmental services team.
“These were some of the largest seas in recent memory.
“It was a big risk and really controversial, but it worked.”
“Last year, the dune was receding at the rate of a metre a month and rubbish was leaking into the sea.”
Ms Perrin said the shire and Department of Environment and Primary Industry had been experimenting with various types of erosion control including matting and mesh fences further along East Beach ,which she regarded as one of the most challenging tasks in coastal Victoria. The shire received state funding to construct a low-budget rock wall called a wave-energy dissipation structure (WED) adjacent to the old tip.
“It was designed by a coastal engineer and built by an experienced contractor using a small budget with shire and state government money,” Ms Perrin said.
“We were shocked to see data from this month’s monitoring conducted by volunteers.
“At all other monitoring posts along the beach there was a sand loss.
“Data suggests that erosion of the dune toe might have been in the order of three metres had the WED structure not been in place.
“Our Port Fairy Coastal Group volunteers have done a remarkable job in monitoring the erosion.”
Ms Perrin said the preliminary results indicated the wall would need to be extended if more of the lower beach was to be saved.
Meanwhile, the shire is awaiting government approval to renew a 92-metre section of the main beach rock wall extending north from the toilet block.
“A long-term solution will cost millions of dollars. The shire doesn’t have that much money,” he said.
“It costs $2000 a metre to build a proper wall with foundations below sea level.”
Next month, Ms Perrin will travel to Canada, the US and UK on a scholarship to glean ideas on how other nations tackle erosion caused by sea level rises and climate change.
She is among five recipients of the Municipal Engineers Foundation scholarship which will require her to produce a summary report which will apply to all Victorian coastal areas.
“We will be studying how other countries tackle the challenges of climate change,” she said.
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