WITH no sand to check the sea's progress, wave energy off Stockton beach has intensified more than 100 times with the potential to destroy roads, homes and critical services, according to new research.
Deeper water due to erosion, coupled with loss of offshore sand banks, has resulted in a "dramatic increase" in the size and power of waves pounding Stockton's shoreline, that experts say is directly linked to the deepening of the Newcastle harbour channel.
According to analysis conducted as part of ongoing research by the University of Newcastle and Newcastle data specialist company Anditi, potential wave energy 500 metres off Stockton increased more than 100 times from 1816 to 2018.
Save our Stockton: The complete Newcastle Herald investigation
Over the same time, potential wave energy 200 metres off the coast increased more than 65 times.
The most significant spike occurred between 1980 and 2000, after the deepening of the harbour channel to 15.2 m between 1977 and 1983.
Anditi managing director Peter Jamieson, a former environmental consultant who spent years studying Stockton beach, said the data was clear.
"It was reasonably stable and it changed dramatically when the channel was deepened," he said. "The timing of the rapid increase can't be ignored. The port operations are going to expand in future years and there is no doubt its operations are crucial to NSW's economy, but it's been at a cost, and the cost is Stockton beach."
As the seabed continues to drop, "massive volumes" of water - like never seen before - are hitting the fragile coastline and stripping sand.
The wear and tear over decades means the beach now lays denuded of its sandy blanket, with much of the foreshore strewn with pebbles and the rubble of millions of shells.
A Port of Newcastle spokesman said it 99-year lease of the port, that includes maintaining the breakwaters and channel that are owned by the NSW government, began in 2014. "It is clear that there are many different and complex factors that could have contributed to erosion over a long period of time," he said.
But University of Newcastle's Conjoint Associate Professor in Earth Sciences Ron Boyd said there was "clear consensus" in expert reports and informed opinion that Newcastle harbour works, including the breakwaters and dredging, were the source of the erosion problem.
"There is no report that identifies an alternative," Professor Boyd said. "There are many reports that identify the harbour as the source of the problem, but the reality is the Port of Newcastle has only recently taken over the lease and it was controlled by the NSW government before that."
Dr Ian Taggart, from the university's school of engineering, and Mr Jamieson said the problem had been put in the too-hard basket for decades and it was now at crisis point where a "Sygna-type storm" would wreak havoc on Stockton.
"If a significant storm surge comes there could be houses washed away," Mr Jamieson said. "Once it gets over the [Mitchell St] wall it's bedlam and mayhem behind it. The Russian roulette bit is you don't know what part of the wall is going to unravel. If a big storm comes you could get a massive unravelling."
From 2000 to 2018 the nearshore seabed has dropped more than two metres, meaning the waves' energy is not dissipated as it would be by gradually shallowing sand. Bigger, meaner waves are hitting the shore with much greater force, relentlessly chiselling at the coast.
Unsightly sandbags and rocks now hold the beach together and make much of it a no-go zone. Despite repeated denials by the City of Newcastle, a chorus of long-term residents say with no sand the Mitchell St rock wall - the only thing that stands between the ocean and a row of homes - is dropping. The swell is now so powerful that residents feel their homes increasingly "shudder and shake" and in storms "four-to-six foot swell" hits the wall unbroken. Mitchell St also has a gas main running along it.
"Unfortunately it's only a matter of time until the road is impacted," Dr Taggart said. "Unless something is done it will happen... I think the council would be happy with rock walling Stockton because its prime interest is preserving its assets, beach amenity is second, but the community wants its beach back."
The Newcastle Herald reported last month that sand loss from Stockton beach had been grossly underestimated. A comparison of NSW government seabed survey data by Dr Taggart and Mr Jamieson found that between 2000 and 2018 on average 85,300 cubic metres of sand, or 136,500 tonnes, was lost from a 3.84-square-kilometre section of the beach every year.
The hardest hit sections included areas closest to the shore and sand loss was occurring in water depths from 12 metres, all the way to the Newcastle harbour channel depths of 18 to 20 metres. The analysis focused on a section at the southern end of the beach, so the full extent of the problem remains unclear.
3D mapping of the findings by Anditi staff reveal dramatic changes at the southern end of the beach, including "drainage channels" running along the northern side of the Stockton breakwater leading to what the researchers believe is causing most of the sand loss, a "large scour" hole at the tip of the breakwall.
Dr Taggart and Mr Jamieson said the large hole, or scour depression - documented in a 1963 NSW government Maritime Services Board report - was acting like a "plughole", ripping sand off Stockton beach. A similar scour depression caused the collapse of Pelican Marina into Lake Macquarie in 2016.
"If you don't block the plughole you can put sand on Stockton beach each year and you could lose it each year, the cycle is only going one way," Mr Jamieson said.
Anditi's seabed contour mapping shows a "steep", "unstable sand face" at the tip of the Stockton breakwater where the scour depression dips to the level of the harbour channel at the port entrance.
Both men believe an engineering solution is the only way to stop the plughole constantly ripping sand from the beach, but said it needed further detailed research and planning.
Dr Taggart said sand nourishment, the community's preferred option to address the erosion crisis, would be most successful if the "loss mechanism" was addressed.
"Sand nourishment will be much more effective if you plug the plughole," he said. "Anything you do to address that will make modest amounts of beach nourishment much more effective, however I fear it's not on any agenda."
City of Newcastle has been tasked with finding a long-term solution to the erosion crisis under its Coastal Management Program (CMP) that will be issued in draft format on May 13. A community information brochure circulated this week said the council was "focused on returning sand to the beach" and "will explore a last line of defense" to protect infrastructure.
The completion of the plan follows decades of delays and millions of dollars spent on temporary measures that many claim have exacerbated the erosion. A City of Newcastle spokeswoman said a consultant was analysing sand movement and would look at changes to the seabed, including sinks.
But Dr Taggart and Mr Jamieson hold little hope for a long-term solution from the much-anticipated CMP.
"The reality is that after looking at the 2018 [seabed mapping] data this has gone beyond getting a sensible beach back unless something significant is done offshore," Mr Jamieson said. "The CMP is the wrong place, in my view, to look at this problem. You need to step back and look at it as a whole. The CMP and the funding available under the program are designed for local problems, where there are local forces at play and this is not that."
Dr Taggart agreed the "eleventh-hour plan", that had its deadline brought forward by the NSW government by six months, wouldn't provide a long-term solution for the beach. "Stockton beach's problem is unique in the state given its relation to port operations," he said. "This is a much bigger problem than what the CMP can deal with."
Port of Newcastle's spokesman said Deputy Premier John Barilario's newly formed Stockton beach taskforce of government agencies and council representatives would "determine the facts and formulate a long-term response". "We remain committed to contributing towards the long-term, fact-based response that is required," he said.
Many residents fear the CMP will simply propose walling the shore. Resident Lucas Gresham said the community had asked for "only one thing". "I don't believe for one second that they would put forward a plan that doesn't include a plan for sand nourishment. If the solution does not have sand, it is not a solution and the community will fight it.
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