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This was published 4 months ago
Waves and wind are eating into the state’s beaches, with some losing almost 30 metres of their breadth in this week’s storms.
“At Narrabeen-Collaroy, we have seen the beach lose an estimate of 29 metres in four days,” said Doctor Mitchell Harley, a senior lecturer at the Water Research Laboratory at the University of NSW.
Sand is washed over Marine Parade in Maroubra on Tuesday after heavy rain and damaging surf.Credit:Peter Rae
“We have had waves of six metres and they have been coming in from the east-south-east, which leads to erosion.”
Calmer conditions in May and June allowed many of Sydney’s beaches to bulk back up with sand after erosion during fierce storms earlier in the year.
Each metre of lost sand takes around five days to replace as new sand washes in, Harley said, meaning it is likely to be four months before the beach at Collaroy returns to the size it was last week.
“But that is assuming there won’t be more erosion events and there will probably be some, with it being the start of July and with La Nina lingering,” he said.
The clean-up at Maroubra on Tuesday.Credit:Peter Rae
All Sydney’s northern beaches were closed yesterday due to the rough conditions.
A Northern Beaches Council spokesperson said Newport Beach and Great Mackerel Beach were most affected by sand erosion.
Sand continued to blow inland from the city’s southern beaches, piling up like brown snow drifts in some places.
In Maroubra, earthmoving equipment was used to push the advancing dunes back onto the beach for the second day in a row on Tuesday.
Maroubra and Coogee were both closed for swimming, with two-metre waves and rough conditions. Some rocks were exposed at both beaches along the shoreline.
The NSW government said it was working with local councils to plan for and respond to erosion caused by major storm events.
The state’s coastal management plan is currently in a transitional phase, with 50 councils up and down the coast at different stages of preparing local plans. Many are still doing scoping studies.
The City of Newcastle is calling for 2.4 million cubic metres of extra sand to replenish erosion-prone Stockton Beach.
Sea level rise adds to the complexities around protecting the state’s coastline, contributing to everyday erosion and supercharging extreme weather events when they occur.
The coastline around Sydney is expected to experience between 20 centimetres and just over a metre of sea level rise in the next seven decades. This means that the state’s coastline can be expected to change significantly as climate change intensifies.
But it’s not all ominous news.
“We are fortunate to have been monitoring Collaroy-Narrabeen every single month for the past 45 years, and we have measured no large-scale reductions over that time,” Harley said. “Beaches are very dynamic, but we have also seen over time that they are quite resilient.”
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