Could replenishing beaches with sand nourishing help solve NSW's coastal erosion problem?

Like many coastal communities across Australia, Wamberal on the New South Wales Central Coast has an erosion problem.

Its beachfront homes, which were battered during severe storms in 2020, face increasingly severe storms and rising sea levels due to climate change, but there is still no agreement on how best to prevent more damage.

Home owners have proposed building a seawall to protect their properties, while many in the community believe solutions such as sand nourishment, where sand is dredged up offshore and returned to the beach, should be used instead.

Local surfer Maia Abell is worried about the possible impact of a seawall on the beach amenity and erosion.

"I feel it's unfair that only the houses at the front get to make the decision," she said.

Wamberal home owner Chris Rogers said while many people living along the beach supported sand nourishment as one solution, building a protective structure was also necessary.

"[We] have been working towards trying to develop and design a protection that would have minimal impact on the beach and protect the homes," he said.

"If you combine that with sand nourishment, it's an excellent opportunity to solve a problem that's been going for five decades or more."

He said NSW needed legislation similar to Queensland where it was stipulated that sand from offshore could be used for beach nourishment.

Communities across NSW have long lobbied their local councils to commit to and implement a range of coastal protection works.

Seawalls, artificial reefs, sandbags, groynes, dune rehabilitation and sand nourishment have all been touted as possible ways to fix the problem. 

Retreating away from the coastline has been considered a last resort.

Coastal engineer Angus Gordon said sand nourishment was one of the most cost-effective methods and had successfully been used to prevent coastal erosion on the Gold Coast and around the world for decades.

"If you look overseas in the United States, for more than 50 years they've been carrying out major nourishment on Miami Beach," he said.

"[And] in the Netherlands, they call it the 'sand engine' and it involves about 30 million cubic meters of sand."

He said coastal communities across NSW could participate in a shared sand nourishment program, using a special dredge to pump sand from offshore onto the beaches.

"The secret is to carry it out on a large scale," he said.

Call for statewide response

According to Gold Coast Council, the cost of sand nourishment varies between $15 to $30 per cubic metre of sand at its local beach.

Mr Gordon argued if a shared nourishment campaign was undertaken, the cost could be around $5 per cubic metre of sand, or less.

He said a recent amendment to the state's environment laws was intended to make offshore sand sourcing for nourishment works easier, but he believed more legislative changes were needed to the state's minerals and coastal acts to make it work more effectively on the ground.

He said a dredging program could target some of the areas with the highest erosion risk, including Byron Bay, Old Bar, Stockton, Wamberal, Collaroy, Cronulla and the South Coast.

"To set up an authority to undertake this work and to coordinate it through the councils."

The authority responsible for managing Wamberal's coastline, Central Coast Council, said it would like to collaborate with other LGAs to roll out coastal protection works, but maintained it would not rely solely on sand nourishment.

"[We support] an engineered structure from lagoon to lagoon that protects the whole of the beach and beach nourishment," council's director of environment and planning, Alice Howe, said.

The idea of a shared program between state and local governments has been welcomed by other communities, including Stockton near Newcastle.

The community has been plagued by coastal erosion problems for decades, with several buildings on the beachfront removed in recent years.

Stockton community taskforce member Ron Boyd said after years of lobbying, 130,000 cubic metres of sand was pumped onto the beach last October.

However, he and many other locals believe it is not enough. 

"We're looking in the order of about 3 million cubic metres of sand [needed] to really make the beach healthy again," he said.

"So that it will last another 15 to 20 years without us having to do this again."

Not a silver bullet

Some critics say sand nourishment is not a foolproof solution because any sand can be washed away during a big storm.

Because of this, many beachfront home owners and businesses believe a hard structure should be established along their property as a last line of defence.

University of Newcastle coastal erosion expert Hannah Power said while sand nourishment could be effective, it was not a "silver-bullet" solution.

"Every community has to make their own decisions," she said.

The associate professor said cost was a significant factor for the decisions most councils made around coastal protection works.

"Even though beach nourishment might be the preferred solution by the community, there simply isn't the resourcing available to fund that," she said.

"For some of our more regional councils, they really just don't have the resources ... to really do what's needed in this space."

The Local Government Association of NSW said it had been lobbying the state government to ensure councils had more support to deliver ongoing coastal erosion prevention works, and had called for the appointment of a coastal commissioner.

The NSW Environment Minister Penny Sharpe declined to be interviewed but in a statement, the environment department said while councils were primarily responsible for managing the coastal environment, the department provided grant funding for coastal erosion management.

"Since 2016, 326 new grants totalling $70.38 million have been awarded to local councils under the [program]," a spokesperson said.

"Grant funding is provided on a 2 to 1 basis; $2 from the government for every $1 provided by the applicant."