Article

Cables Reef Study

| posted on October 11, 2010

Last week, Chad Nelson at the Surfrider Foundation sent an interesting email. In it, he basically retracted a statement made in an earlier OneWorld article that the jury was still out on the success of Cables, an artificial surfing reef in Australia.

Along with his note, Nelson sent a detailed study on Cables by Charitha Pattiaratchi, a scientist with the Department of Environmental Engineering at the University of Western Australia. Essentially, she found that this man-made Western Australian surf spot was performing as well, or better than predicted. In fact, at a previously unsurfable location, there are now rideable waves an average of 150+ days a year.

Cables Station sits in the southwestern corner of Australia, near Cottesloe, directly in the track of swells generated by “the roaring 40′s”. In the vicinity of Cables, much of the coast is shadowed from swells by offshore islands and reefs. After much study and debate on issues like wave refraction, underwater topography and environmental impact, the government of New South Wales agreed to build the surf reef in early 1999. Construction consisted of limestone rocks dumped atop an existing reef in a “boomerang” formation. This triangle shaped reef would trip up the incoming swells, hopefully, creating a right and left peeling wave.


After testing different designs in a wave pool, the reef was built with a 3 meter depth contour and at a 1:20 slope 175 yards offshore. Length of rides would hopefully be from 50 to 80 meters in length for the right, and 30 to 40 for the left, depending on the swell direction, height and size.

In her study, Pattiaratchi measured “surfability” of the wave here. While this is obviously a subjective measure, she defined the term thusly, and measured it with a 24/7 webcam: (a) presence of people out surfing on the reef (which could be seen in the web cam images); and/or (b) visual assessment that the wave size and shape would be conducive to surfing.

With the exception of occasional technical glitches, the webcam filmed the spot night and day, giving a first real, scientific look at whether or not a man-made reef was doing what it promised. She found that the wave here broke at all stages of the tide, anytime the swell was greater than a half meter in size. At under a half meter, it still often broke at low tide.


So what does this all mean? Well, it certainly gives ammunition to proponents of artificial surfing reefs. Today, there is a functioning, studied spot off the coast of Australia that, unlike groins, jetties or sand pumping, was deliberately created for surfing.

What’s next? Well, it will be interesting to see if any sort of an economic benefit analysis is conducted on the Cable Station reef — from such a study, a researcher might discover whether the reef was drawing surfers from out of town to spend money in the Cottesloe area. It will also be interesting to see if, in the long term, the reef has any negative environmental impacts, or if its limestone rocks become a haven for fish. Early results from Pattiaratchi seem to show that environmental degradation and beach erosion have been minimal.

With artificial reefs hoped for on the coasts of Santa Barbara and San Diego counties and even on the faraway shores of Newquay, Cornwall, this idea is clearly gaining momentum. However, despite all the yammering, Australia’s Cables and Narrowneck are the only two surfing specific reefs that appear to be doing what they were designed for. Despite high hopes, Pratte’s Reef off El Segundo in LA failed to deliver.

The question also remains — if you build an artificial reef that produces great waves, will you just end up creating another Lower Trestles — simply bringing more people to the beach and not reducing crowds at all? Perhaps. But it’s equally true that with the exception of a few volcanic hotspots in Hawaii, Mother Nature is mighty slow to create new surf breaks on her own.

Click
Here to See Dr. Pattiaratchi’s Full Presentation

Click
here to Check out the Cables Cam