A drop in the ocean

For decades, residents along a section of suburban Australian coastline have witnessed their beach dissolve before their eyes, sometimes literally dropping into the sea. It’s a problem that is also confronting coastal towns throughout the country — and the world — as sea levels continue to rise.

Across Australia’s suburban beaches, a battle is currently underway. But the combatants are not rival armies — they are rival elements.

Water washes away earth, sand succumbs to swell.

King tides and powerful waves slam into last-defence sea walls.

Sea spray spatters footpaths and, in some suburbs, erodes entire sections of shore.

The consequences are all too familiar for locals at Adelaide’s West Beach.

Even during calm weather, their beloved shoreline is a site of constant ebb and flow.

“My kids have always seen their beach basically dissipating before their eyes, eroding away,” local John Dundon says.

“[They] have always had trucks on the beach.”

While human development has exacerbated the problem, human intervention is keeping the tide at bay.

Sand-carting sees tonnes of raw earth moved along the length of Adelaide’s coast, taking from the sand-rich to give to the sand-poor.

Despite the noise of heavy machines, Mr Dundon is thankful the trucks are there.

He’s seen king tides eat away at West Beach’s dune face, with huge chunks of sand falling into the sea.

“It was just sad, it was horrific to watch,” he says.

“We were heartbroken. You could see the erosion and the loss happening before our eyes — after every storm or high tide, there was erosion.”

Other beaches in metropolitan Adelaide, including the popular tourist towns of Glenelg, Henley and Brighton, are facing similar challenges.

Some of the reasons stretch back decades, but others stretch back much, much further.

Longshore drift along Adelaide’s coast has been a natural phenomenon for thousands of years.

Waves mostly come from the south-west, pushing sand to beaches further north.

But when urban development accelerated, and sprawl extended to coastal regions, entire suburbs were built on top of extensive stretches of sand dunes — natural barriers that are supposed to replenish beaches after major storms.

The result has been widespread coastal erosion.

But the problem is hardly confined to Adelaide.

Coast to coast

Australia is a nation that is “girt by sea” — about 87 per cent of people live within 50 kilometres of the nearest shoreline, giving them a front-row seat when it comes to rising sea levels.

On the Gold Coast, huge efforts have been made to protect the shoreline.

On the New South Wales-Queensland border lies the Tweed River.

After the mouth was artificially extended, sand became trapped and started piling up on the NSW side of the river.

But, in 2001, authorities came up with a solution, at a cost of several million dollars.

On average about 500,000 cubic metres of sand are pumped from the NSW side of the river to the Gold Coast’s southern beaches per year.

Amid a warming climate and rising sea levels, perpetual intervention will be needed to save beaches around Australia, says Flinders University’s Graziela Miot da Silva.

“More frequent storms, stronger storms, bigger wave energy — these are the main threats that shorelines are facing,” the oceanographer and coastal geomorphologist says.

Dr Miot da Silva has studied changing coastlines in Brazil and other parts of the world.

For those looking to come up with a solution, part of the problem is that the capacity of nature to respond on its own has been compromised by decades of urban development.

“Most coastlines will try and adjust with the wave climate,” Dr Miot da Silva explains.

“Because we built roads and infrastructure and we fixed the shoreline in place, we got in the way of this transition.

“Now we’re not letting that shoreline adjust anymore and that’s why we’re experiencing erosion in some places.”

The Dutch defence

As they search for answers, engineers are seeking inspiration on the other side of the world — in the Netherlands, a nation that largely lies below sea level and is constantly buffeted by the North Sea.

“They are the world leaders in coastal engineering,” Dr Miot da Silva says.

For years, the Dutch have seen their coastline dramatically change on a regular basis.

Delft University of Technology’s Sierd de Vries has been studying his country’s disappearing beaches for more than a decade.

The coastal engineer says major sand-carting operations to replace 10-to-15 million cubic metres take place on the country’s shoreline each year.

“The Netherlands is a low-lying country — almost 50 per cent of the country is below sea level,” Dr de Vries says.

“It means if we experience flooding, it’s very serious.”

Returning a landscape impacted by human hands to a more pristine state can be done via a process known as “beach nourishment”, which includes sand-carting and pumping sand through tunnels.

It avoids the need for harder structures like groynes, breakwaters and sea walls, and has already been attempted and adopted on some Australian beaches.

Mr de Vries has worked on one of the biggest nourishment experiments in the world, called the Zandmotor, which means “sand engine”.

Over 20 million cubic metres of sand were sourced from the North Sea between the United Kingdom and the Netherlands, and brought to the coast close to The Hague.

The strategy was implemented in 2011 and is designed to last 20 years.

“The amount of these nourishments, and the way these sediment nourishments are implemented along the Dutch coast — they are written in the law,” he says.

“We’ve seen today the sediments spread along the coast, compensating for the structural erosion while at the same time creating a dynamic landscape.”

‘The price we pay’

Back along Adelaide’s beaches, a similar set of challenges is confronting local engineers, albeit on a smaller scale.

“I’ve seen the water getting into the sea wall here,” Dr Miot da Silva says of the coast at Brighton, in Adelaide’s south.

“During high tides, king tides, storm surges — we don’t even need big waves.”

After major storms in the 1950s and 60s, beach walkways and other infrastructure began collapsing into the ocean, and sandy shorelines started to visibly shrink as dunes disappeared.

“If you don’t have that buffer, the waves and wave run-up will attack whatever is on the back of the beach,” Dr Miot da Silva says.

“We lost that extra storage of sand to cope with storm events.”

Polluted rivers have also led to the death of seagrass beds, which are natural “shock absorbers” for waves when they approach the coast.

In response to rampant erosion, the state’s Coast Protection Board was formed in 1972. It was the first organisation of its kind in Australia, and was tasked with combating Adelaide’s coastal damage and deterioration.

Soon after, work began on carting sand back to the beaches that were disappearing. Since the 1970s, over 4.5 million cubic metres of sand have been shifted along Adelaide’s coast.

A 7-kilometre underground pipeline from Glenelg to Kingston Park, south-west of Adelaide, was built in 2012 to pump sand back to the southern beaches.

In addition, sand-carting trucks tipped 50,000 cubic metres of pre-washed quarry sand onto West Beach in 2022. 

There will be another delivery this autumn, costing the SA government up to $7 million within one year.

But the cost has been more than financial.

At times, the coast can resemble a minefield — both literally and figuratively, because sand-carting has not been without controversy.

Reclaiming sand from northern beaches has caused tensions between different communities, creating a “north-south” divide of sorts.

Some locals regard the process as a major disturbance, cluttering their beaches with trucks and tyre tracks, while others see it as a necessary means to an end. 

For now, carting sand continues in problem areas, although some projects have been halted with the change of state government.

One of those was a proposed pipeline that would pump more sand to West Beach from Semaphore South, which is further north.

The new Labor government instead called for a 12-month review, starting in early 2023, to consider any alternative options to help manage Adelaide’s disappearing beaches.

But regardless of what precise plan is implemented, Dr Miot da Silva says that more, not less, intervention will be needed.

“It’s expensive, it’s inconvenient,” she says.

Credits

Reporting: Evelyn Leckie 
Photography: Che Chorley
Digital production: Evelyn Leckie and Daniel Keane
Graphics: Stephan Hammat
Editor: Daniel Keane and Jessica Haynes
Additional photography: Transport for NSW, Frank Auperlé, Jurriaan Brobbel and Ray Murray via Messenger Press