It's known for its remarkable beaches but the Gold Coast has a surprising problem – it's slowly running out of sand reserves.
A report on the city's surf management strategy handed to council's Transport and Infrastructure Committee in January stated that the sand imported to the area to mitigate erosion was "finite".
It stated: "It must be acknowledged that the sand required for the ongoing nourishment works to manage erosion of our ocean beaches is a finite resource".
"It must also be acknowledged that the more activity and development seaward of the 'A-line' [Surfers Paradise Esplanade], the greater the exposure to the risk of severe damage and loss in an environment of ever-decreasing sand reserves to mitigate those risks in perpetuity."
A City of Gold Coast spokesperson said council was confident that existing offshore supplies provided a secure source of sand, with "investigations to identify new sources of sand to supplement existing reserves" underway.
But it's not the only issue facing city planners, with coastal management researchers warning climate change will pose new, long-term challenges.
What's being done now?
Sand bypass plants at the Tweed River and the Gold Coast Coast Seaway assist the natural flow of sand along the coast as a safeguard against beach erosion.
Last year, the Gold Coast City Council also dredged Tallebudgera and Currumbin Creek, providing about 60,000 cubic metres of sand to replenish beaches at Burleigh Heads and Palm Beach.
In January, council moved sand from a development site in Surfers Paradise to replenish Narrowneck Beach.
Other measures include an underground seawall at Surfers Paradise, and an artificial reef at Palm Beach, along with coastal monitoring and research.
Modelling published by Griffith University last December suggested that the city's two bypassing plants "would receive [and therefore pump] less sand" due to the changing coastal environment, meaning that sand erosion associated with extreme events could potentially increase.
Tom Murray from Griffith University’s Coastal and Marine Research Centre said sand needed to be replaced after storms.
"We know the sea level is rising. We know the wave climate is going to change. We know the behaviour of storm systems is going to change," Dr Murray said.
"If we're not getting sand to replace the sand that's lost after a storm, that's an issue.
"[But] it's not just big storms [that] equal big erosion. We saw at Byron two years ago, the main beach was eroding and it was actually … a natural process that occurs under low-wave energy conditions.
"What we need to be doing is constantly monitoring these changes to understand them through time so we can future plan."
Beyond the beach
Hannah Power, an associate professor from the Environmental and Climate Change Research Group at the University of Newcastle, said short-term political cycles created a "psychological challenge" for long-term planning.
"It can be hard for people to grasp the idea that in a hundred years' time, if the beach is left to its own devices and there was no infrastructure or seawalls or properties behind the beach, it might actually be sitting 100 metres landwards of where it is today," Dr Power said.
"We need to look at minimising how much additional exposure we add to our coastal zone by minimising how much infrastructure and property we build in regions. That may be acceptable now in terms of risk, but won't be in 20 years' or 50 years' time.
"Think all the canals on the back of the Gold Coast, those properties are really at risk from extreme sea levels."
On top of the challenges posed by sea-level rises, the federal government's Severe Wind Hazard Assessment Technical Report concluded that canals "create stretches of water within suburbs. The reduced terrain roughness this introduced exacerbates severe wind speeds locally leading to higher risk".
A 2021 climate risk assessment report stated that more than one in 10 homes on the Gold Coast were at high risk of becoming uninsurable, due to unaffordable premiums.
'Managed retreat' the last option
Dr Power said a federal body was needed to help local governments adapt to coastal changes and conduct research.
"There are so many different factors from local environmental factors, to budget, to risk appetite that'll play into what is going to be the best solution for an individual community," she said.
"One of the challenges is that our cycles of government are much shorter than the planning horizons we need to be thinking about."
Dr Murray said the challenge for town planners and governments was to manage how people live in the coastal environment when the landscape was constantly changing.
"One of those options, which is the real elephant in the room, is managed retreat," he said.
"Always seen as the last option is to move everything up and inland, but managed retreat doesn't actually have to mean the movement of infrastructure.
"It can actually mean how we live with a dynamic environment and adapt the way we live or adapt certain structures.
"[It's] the very last step."
