READING of a proposal to have 200-kilogram hollow “aquatic pyramids” installed as a sea-wall in front of Stockton Surf Life Saving Club set me thinking about all of the other ideas that have been tossed upin the decades-long battle against sea erosion at the southern end of Stockton Bight.
SWIRLING SANDS: conceptual model of Stockton sand movement. Source: Stockton Beach Sand Nourishment Scoping Study.
As it happens, the first article that I wrote that made the front page of the Newcastle Herald dealt, in the late 1980s, witha plan tobuild groynes at Stockton as a method of erosion control. Later on, there was a push to have an artificial reef, or reefs, with a Lake Macquarie engineer and surfing obsessive, Robert Sirasch, being a vocal proponent. Alert observers will have noticed that nothing came of either idea,but Siraschis still around, and when I spoke with him on Friday, he directed me to a range of reports that have been done on Stockton over the years.
These investigations mean the authorities should have a detailed understanding ofsand movement in and around Stockton Bight.In general terms, sand travelsfrom the south to the north on this part of the coast, but the artificial nature of the entrance to Newcastle harbour tends to impede this movement, as does the unusual depth of the harbour entrance.
The harbour entrance acts as a barrier: sand thatwould normally migrate to the southern end of Stockton Beach does not get there, although the supply is bolsteredfrom time to time when the port authority, dredging clean sand from the harbour entrance, drops it north of the harbour off Stockton, where wave action eventually pushes it in.
The other major impact at Stockton is the sea-wall built on the beach next to Mitchell Street, running some 500 metres from Pembroke Street at the south to Stone Street to the north.
Environmental consultant Doug Lord, who was involved in some of the Stockton studies when he was a coastal manager for the NSW Department of Land and Water Conservation, says the sea-wall stopped the erosion, but the wave pressures remain, so there is very little sand in front of the rocks, especially at high tide.Lord says thishas “pushed the problem north”, meaning thaterosion is increasing north of the sea-wall as the beach “tries to find its new alignment”.
As it happens, this kilometre-long stretch from Stone Street north to the Hunter Water sewage treatment works is also the narrowest strip of coast, with less than 400 metres of low-lying land separating the ocean from the Hunter River, with the edge of Kooragang Island another 500 metres away across the channel.Further north, the impact of erosion diminishes untilan “equilibrium” point is reached, just north of the Stockton Centre, parallel withFern Bay.
PLUSES AND MINUSES: Options on Stockton beach recession management prepared in mid-2000s.
North of here, things are not so critical because there is no beachfront develop and the dune system is still relatively intact.Things are alsostable at the far southern end of Stockton Beach, meaning that all of the pressure is concentrated on that one central area of North Stockton.
A study donefor Newcastle City Council about a decade ago compares a dozen options for the Stockton foreshore, ranging from doing nothing to the most favoured approach, an artificial headland –a triangular-shaped rock headlandsticking out into the surf, beyond the usual line of breakers. But at $25 million, it was also the dearest option, and so nothing has come of it.Shame, really, because as well as the erosion benefits, I can’t help thinking of the great waves such a headland could generate. If we are going to save the coast, we may as well have fun doing it!
Sea-walls and swells: a very Stockton story Seawall facing south
Seawall, facing south
From monument area facing north
Monument area, facing north
Monument area, facing South
Stockton Surf Club
Definition of coastal terms
TweetFacebook Erosion at Stockton after 1999 storm.Images from Stockton Beach Coastal Study, progress report #4, Newcastle City Council, 2006.