Interview with Professor Kerry Black

SJ – Will they build and test a scale model to show the affects on tidal flows, waves, and currents?
Kerry – What has happened in the last 10-15 years is that the computer/numerical models have become much more sophisticated; and they are much more versatile than the scale models because you can do a lot more different shapes and sizes and change parameters so much easier in a mathematical model than you can in a hard concrete or wooden physical model. Also the physical models have some disadvantages with scale affects and you need a very large model and they get very expensive.

 

SJ – You were involved with the Narrowneck project at one point weren’t you?
Kerry – Yes. What happened in the Narrowneck case was that I did all the design with a mathematical model, and the client was very keen to see a physical model done, and while I was of the view that this (wasn’t necessary), they were still very keen to see it done and I supported that. In the end the physical model gave the same results as the mathematical model, and so the project was approved and it went ahead.

 

SJ – Ex chairman of the British Surfing Association and now a Gold Coast Local ‘Ron Williams’ said to A1Surf that there were rumours of it sinking, but within reason the actual maintenance of the reef to dump a few extra sandbags there wouldn’t actually cost you much in theory?
Kerry – No. In terms of cost versus construction, you can go to a large amount of cost to make sure that it does not move at all. Or you can place a few bags and with the expectation that it will sink slightly, and then you just put that in your building plan, and you allow for that in you final design so you need to put about a metre perhaps of extra height on the bags. It turns out it was known that it was going to sink to some degree. The main factor on the Gold Coast though is that the reef is not completed; and has not been fully built.

 

SJ – So if they expected a typhoon to come to come by, not if but when, then the maintenance would have to be maintained on that?
Kerry – No! The original sinking is just the bags settling into their cocoon of sand and so on both sides.

 

SJ – So you don’t expect the sandbags to move?
Kerry – To keep it at it’s absolute best, there might every 5 or 10 years, be a requirement to add a few extra sandbags to the reef. But really the bags themselves are gigantic; they’re more than 200 tonnes each.

 

SJ – Bearing in mind the winter storms we get here, especially off the hurricane season; within reason those storms can move a shipwreck the size of a sunken navy boat. How do you anticipate that moving the reef around the bay?
Kerry – What happened with the Gold Coast reef was that the Reef had to be designed with a wave height that was huge; it’s a cyclone area. And the size of the waves and cyclones are as big or bigger than here. Also the reef is in slightly deeper water on the Gold Coast than what it’ll be here. It’s in nearly 10m of water, which means you can get on a high tide about a 12/15m wave breaking high. The stability of the reef was tested in a scale model, a different one to the design model. This one I strongly supported; it was a model that looked at whether the bags would move under a large wave attack, and it was found that they did not move as placed as a group as a reef, but if a single bag was placed on its own or if the bags were slightly under inflated, if you don’t fill them up with sand enough, they creep and flap and can destroy themselves, but the technology now is well and truly understood. The inflation levels are a 100% known, and so the predictions and the results have shown the reef on the Gold Coast has been through a cyclone, or a very large one, not strictly a cyclone, a very large swell over the last summer.

SJ – What will be the effect on the surf behind/shoreside of the reef?
Kerry – The reef creates a gradient in wave height, and when it breaks on the reef it will be lower wave heights than the immediate beach. The waves tend to wrap in from both sides. So what happens with the Gold Coast is that predictions by the computer model were that the reef would create a type of interference pattern, the waves coming down both sides of he two halves, when they overlap inshore create an interference pattern that was nicely spaced to create a banking channel.

 

SJ – But within reason it will create rips and channels in the bay. What affect do you think this will have on bathers and swimmers?
Kerry – Well that happened to the Gold Coast. Now here I am not convinced that we’ve got the space or the opportunity to do that because we have the headlands, you have a much lower gradient of the beach, you have a much bigger tidal range. Therefore, the main benefit inshore is probably going to be the fact that the reef will create some hyped gradients that then maybe give a chance to stop the wave closing out, and create some peaks that might be of benefit to the people on the beach, because presently the beach mostly closes out, so there is a potential there to get an improved wave condition even if we don’t change the sandbars, just by the sheer fact of the change in the wave heights.

 

SJ – Is it correct that the sand needed for the project will be dredged from the Camel and Hayle estuaries?
Kerry – We do not know yet as the contract for construction is not in yet. The only area I am insistent on at this stage is that we do not have any polluted sediments in bags. I am not qualified to comment on British estuary dredging!

 

SJ – In regards to the El Segundo reef. There were people saying that the reason why it never worked was because it was too deep and too far out. But they said that the reason for that were political concerns and that there was possibly a conflict of interest there because they were concerned about liability of injuries on the reef.
Kerry – It is really where surfing reefs have become achievable that it is a very important thing for surfers to realise that litigation would set back the industry a long way and it is certainly not to be encouraged. The reason we are able to go ahead is we have got the technology, these geo-textile sandbags which is essentially a ‘beach in a bag’, that is the safest possible material that could be used. Our advice that I have had, independent advice, not from Newquay but from New Zealand is that were taking all possible care with the construction and materials that are being used. If you put an extreme wave on a jagged rock reef then it would be obvious that you hadn’t thought through the issues, and surfers and surfing realise that it is an extreme sport and therefore there is always some risk of injury, but we are imposing a situation that is actually much less risky than a coral reef or a rock reef.

SJ – You said you’d visited our shores in the early 70’s before you were at University in Hawaii in ’75-78 I believe? So what made you choose Britain as one of your first overseas travel experiences?
Kerry – Yes, I surfed Great Western in 1972. I started surfing the same time I started my first university degree, and then I gravitated towards beach and coastal surfing. After that I was lucky enough to win the scholarship to go to Hawaii for two years to do my masters degree.

 

SJ – That must have been like a Golden ticket?
Kerry – It was. I lived on the North Shore and rode it and surfed every day in one of the biggest and best winters that they had for quite a long time. So it was an incredible thrill and a great opportunity. Since then I have spent a lot of time working and travelling through Indonesia, Australia and around the Pacific Rim.

 

SJ – Do you miss your ‘younger days’?
Kerry – I do a bit but I believe I am surfing nearly as well as ever and I am still travelling as this work is giving great opportunities. I am here in Newquay at the moment, nut I am now heading to Southern India where I am doing a job there on coastal management planning and that will get me back on the surf. I’ll be living in a grass hut with a nice balcony which overlooks two beaches with great surf and 30 degree water so I am really pleased. The next contract I am doing is actually by one of the best breaks in Indonesia (Lombok) so I’m not really missing my youth.

 

SJ – The reputation British surfing has overseas is very poor, and trying to build on our reputation and say that we do get waves and surf is very hard in an international community. Do you think this project will put the UK as well as Newquay on the worldwide map?
Kerry – Yes, I really do. People come to Britain for a range of reasons including the surfers, and Britain is blessed with a great swell. They just have a really bad geology that does not have the geology that gives the horizontal reefs at places like Bells beach and Torquay (Australia) has. You have got very steep cliffs and a big tidal range, which flattens all the beaches out. So I think that is going to attract a huge amount of international attention.

 

SJ – What do you think of Newquay and Britain as a whole since when you first visited in the 70’s?
Kerry – It has developed a few more years; there are some great nightclubs and night-life. It has not fundamentally changed. The key to Newquay is the beach and the Cornish environment which is still really good and has not changed as much as some people might think.
Kerry – Another thing my company ASL Ltd is doing is that we have got a patent and a fully workable scalable model of an inland wave machine that produces classic waves in a pool and the project is well advanced. We have joined forces with a company in America which is a big manufacturer of inland pools, and although they have been making waves in these pools we have greatly improved the wave machines. As a result we are getting good 8-10 second waves up to 8ft on the peak and 70-80metre rides full blown quality surfing; we’ve also got a series of pools for beginners who may want to learn to surf in their environment. So they can go in there at night, especially those who cant get in in the day. It is unlike the Flowrider project which is like a skateboarders or a snowboarders wave, as this pool is like a pure surfing wave, quality wave so you can go to tubes and not tubes and so on. So we are hoping these pools will open up in Florida or new York state, but there are none yet, there are no buyers out there, no one has decided to go ahead and fund one.

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