Breakwaters and surfing's happy accident
See also: When Breakwaters equal broken water
When the surfing world reflects on 2017, ‘wave pools’ are the most likely topic that’ll come to mind. In the space of a few years, wave pools have moved from fantasy to reality and they’ve become so popular there’s now a wave pool industry with competitors vying for primacy, investors seeking the best return, and surfers arguing over every single thing about them.
Before wave pools, however, there were artificial reefs, and when you look at it like this it seems surfers have always had a thing for imposing our will on the coast and creating waves. Yet what’s been overlooked in the rush is the enormous amount of waves that have already been created for us. Waves that were created inadvertently, mind you, but they were created nonetheless.
Construction of Australia’s first man made wave began in 1820 shortly after coal was discovered at Newcastle. On the back of convict labor a breakwall was commenced to link the mainland to Nobby’s, a small islet 100 metres offshore. Lack of funds and an abundance of swell saw the work continue only sporadically till in 1846 a causeway linked land and island. It was shortly followed up with a longer breakwall which redirected water and scoured a deep channel on the north side.
If naming Newcastle Harbour causes anxiety then stop reading now as more East Coast gems will be revealed before this article is over. And the East Coast it is, save for one or two spots - here's looking at you Mandurah! The reason for the geographical exclusivity is the Great Dividing Range and the river systems that flow east from it. Because of the mountains we have the breakwaters - and the accidental waves they create.
Through the latter part of the 1800s, trade routes up and down the coast were reliant on sea transport, and this meant bars had to be crossed. In their natural state - that is, without training walls - river mouths tend to be broad and shallow, the deepest channel always shifting due to longshore drift, swell, or even rainfall. In these conditions every crossing was a coin toss and the list of shipwrecks, not to mention the lives lost, began to stack up.
One of the people to work on this problem was an unlikely fella named Walter Shellshear. Walt was a railway engineer, and between overseeing NSW’s great railroad expansion, he studied river bars in his spare time. In 1884 he published a paper 'On the Removal of Bars from the entrances to our Rivers' in which he devised a two-pronged solution.
On the seaward side, Walt stated with military drama that "the battle is to be fought with the waves" - meaning a rivermouth should be fixed and stationary irrespective of waves. While he was more yielding on the inland side observing that each river needs to be assessed individually so training walls can “assist the operations of Nature instead of opposing them."
It goes without saying that surf amenity wasn’t considered, it’d be at least a quarter-century till Tommy Walker would stand on a surfboard in Australia, yet Walt’s great civil contribution - the rockwalls not the railways - would eventually benefit every surfer who lives near a river mouth.
Just a few years after Walter’s paper was published his theory was put to practice: in the 1890s both the Richmond River at Ballina and Tweed River would get their first training walls.
Down the coast, the largest river on the East Coast, the Clarence, had training walls built just upstream from the bar. The rock was quarried from nearby Angourie, and when the workers blasted too deep they disturbed a freshwater spring, the result was Angourie’s ‘natural’ swimming holes, the Blue and Green Pools.
On the south coast, training walls were built at Moruya in 1907, which were upgraded when a stone quarry was opened nearby. Moruya's training walls took priority as throughout the late-1920s Moruya granite was shipped north where it was used in the pylons to the Sydney Harbour Bridge.
By mid-century coastal engineers had built numerous river training walls along the East Coast and they had ample opportunity to assess if Walter Shellshear’s theories were working. The verdict? ...sort of. On the inland side, a channel was indeed scoured out improving navigation, however they found that on the ocean side the bar simply moved a bit further offshore. Part of the reason was that training walls only ever extended as far as the tide line, not beyond it, and sometimes they were only built on one side of a channel.
Research in the 1960s concluded that breakwalls, where possible, should be on either side of a river and they should extend into the surf zone. We surfers should be thankful for those findings.
A breakwater doesn’t create waves the way a wave pool does, but it can greatly increase the size and quality of existing waves. The propensity to increase swell size is dependent on how each breakwater juts into the ocean. A well-aligned breakwater - or conversely a well-directed swell - will see swell energy ‘bounce’ off the breakwater at an angle to incoming swells which amplifies wave height and in turn making it break faster and pitch further.
Increased quality can come not only from the above scenario, but also from proximity to the offshore river bar which breaks up straight lines of swell into random peaks. There’s also the less recognised matter of wind protection. The best breakwaters, and there’s a few, create the kind of waves that have eluded artificial reef designers for years.
In the 1950s and 1960s coastal engineers took their great leaps forward and unwittingly created new waves up and down the coast. Lots of waves! Great waves! The Clarence River had its breakwalls extended, of interest being the south-east alignment of the breakwall on the northern side. Forster had a breakwall erected on the Tuncurry side. The Tweed River breakwalls were extended at Duranbah. Also, Evans Head, Brunswick Heads, and Port Macquarie had their breakwalls extended.
There were also the breakwalls that didn’t create wedges but improved wave quality in other ways. In 1972 Kirra Groyne was constructed, while a year later a breakwall was built to join Currumbin Rocks to the mainland. This last one was followed up with a northern breakwall built in 1981 that fixed the Currumbin channel to its present location and stabilised the bank.
With the extension of the Tweed River breakwalls and the construction of Kirra Groyne, Kirra point was stripped of sand, which in hindsight was the ideal state for classic Kirra. For twenty years Coolangatta surfers enjoyed Kirra like that before the Tweed River Sand Bypass System swamped it once more.
The Tweed bypass system wasn’t the first bypass system on the Gold Coast, that honour goes to the Gold Coast Seaway which was not only the first on the Goldy but the first in the world. Prior to 1986 the Southport Bar was a treacherous crossing for boaties setting out from the Gold Coast’s expanding northern suburbs. Abutted by The Spit to the south and Moondarewa Point to the north, the bar was an unpredictable channel that shifted with each storm. In fact, it moved so much that the town of Moondarewa on the southern end of South Stradbroke Island was lost when the bar migrated north in the 1930s.
Historical photos show Southport Bar to be a broad delta of shapeless shoals. In 1986 the breakwalls were constructed and the bypass system started pumping sand. Almost immediately the banks at The Spit stabilised and north end surfers celebrated over “the Gold Coast’s latest surf spot” largely unaware of what was developing 200 metres away on the north side of the structure. It would only be a matter of time before they figured it out, and not too much later before everyone else did too.
To be fair, South Stradbroke owes its quality as much to a constant supply of sand as it does to the breakwall, yet any debate about quality is academic. Up and down the East Coast there are simply too many examples of classic breakwater waves to argue against their value. And though the wave pool industry is kicking into gear it still has a long way to go to catch up to the bountiful work those coastal engineers of yesteryear laid down for us surfers.
See also: When Breakwaters equal broken water