Perth-Scarborough artificial reef/superbank

PedroStanley's picture
PedroStanley started the topic in Thursday, 5 Dec 2013 at 11:53pm

The WA State Government are looking for ideas for Scarborough in Perth. Scarborough is all about surfing and what better way to celebrate Scarbs than an artificial reef or super bank right out the front? A well designed one that works.

Get on the website and tell the WA State Government its time they listened to Perth surfers!

PedroStanley's picture
PedroStanley's picture
PedroStanley commented Thursday, 5 Dec 2013 at 11:54pm

This is the website
www.scarboroughviews.com.au
get on and tell them

thermalben's picture
thermalben's picture
thermalben commented Friday, 6 Dec 2013 at 5:50am

A second artificial reef in Perth? Can't see the government investing in that having already spent money on Cables, which hasn't really changed the local surfing landscape.

Besides, you'll have to show them a real live working example of a "well designed one that works".

dave_anning's picture
dave_anning's picture
dave_anning commented Friday, 6 Dec 2013 at 10:30am

Might find that difficult, Ben.

WRL recently conducted an international review of artificial reefs, the full report is here.
http://www.wrl.unsw.edu.au/site/2013/11/international-review-of-artifici...

Bottom line, pretty hard to design a reef for multiple purposes or surfing alone.

thermalben's picture
thermalben's picture
thermalben commented Friday, 6 Dec 2013 at 10:57am

Thanks for the link Dave (no surprises there!). It's a long read so I'll download it and check it out over the weekend.

southey's picture
southey's picture
southey commented Friday, 6 Dec 2013 at 1:02pm

The first bit of that paper is very NSW centric . As in the aims are for viability for NSW coastal environments .

And the issue with the entire East coast , is multitudes of swell directions .
So even a reef designed for beach protection is going to struggle to meet its aim , as the sheer size needed to protect the inshore is enormous compared to the actual size of coast protected .

Perth's different , but generally lacks swell .

The obvious place to test , and I'm talking offshore deep water structures to break up the swell , would be the Mornington Peninsula . Now it does get good banks naturally , but as soon as the swell gets over a Generous 4ft , its puss . Frustrating to see so many days of straight solid swell go to waste . The bonus of submerging a swell fracturing object is that it could be aimed at the higher end swell sizes , hence greater period , and deeper water location of the submerged structure making it easier for the construction process that would invariably be carried out in the quieter swell months : summer time .

How good would it be to create another Beacon , West Cape , Boodj , D-Bah , TOS set up ......

" SA's Reserve Capacity "

thermalben's picture
thermalben's picture
thermalben commented Friday, 6 Dec 2013 at 1:52pm

Yeah I agree with that approach southey, much like a permenant 'sand slug'. Not sure if the MP would be the best place for it (probably would work OK; I'm just not sure on the local bathy) but I think these kinds of artificial reefs are the most viable way forward.

uncle_leroy's picture
uncle_leroy's picture
uncle_leroy commented Friday, 6 Dec 2013 at 2:23pm

Some of the big concrete modules used for breakwalls made into an underwater reef 300m offshore at scarborough would be a good idea every few hundred metres along the beach, would cause the swell to refract and create peaks in an otherwise closeout length of coastline.
If it started to have adverse effects on the beach with erosion or something, simply winch them back up again and take them away and the beach will return to the closeout it was previously.

crankitupto11's picture
crankitupto11's picture
crankitupto11 commented Thursday, 6 Feb 2014 at 7:48pm

I'd definitely like to see some artificial reefs along Scarbs. 95% of the year the banks are crap and it just closes out, even when we do have swell.

Jahny9's picture
Jahny9's picture
Jahny9 commented Tuesday, 20 May 2014 at 2:44pm

How about the beach at pyramids. A man made structure that was poorly executed for wave potential. If they could remove the dog leg section, the potential for a really nice wave is there. Similar to the DBah set up.

simba's picture
simba's picture
simba commented Tuesday, 20 May 2014 at 4:50pm

Possibly a cheap way to create banks is to drive pylons into the sand and let the sand build up around them,surprising how well and quick it works as in the coffs harbour sewerage out fall which was temporarily built to lay the pipes out to sea and the sand that formed up around the pylons or near them was awesome.Probably only need them a meter or two depending on depth.That was on an open beach with a lot of sand flow but quite open to southerlies.

simba

groundswell's picture
groundswell's picture
groundswell commented Monday, 15 Dec 2014 at 12:29am

Jahny i agree, breakwalls often work if set on the right angle. Even the breakwall at sand tracks, near the docks south of the cables artificial reef, whicj has excellent potential if it got more swell.
But has the same lack of swell as cables reef. Cables reef could be great if it got more swell or was open to SE swell buts its only open to NW swells are wrap ins from the biggest west swells.

A certain spot i wont name near gracetown like setup would be ideal imo, or a few of them. outer reef peaks up the swell then it peels and wedges across the inside shelf. Also can handle some wind as the bombie lets the swells wrap in semi off in the wind.Doesnt need much swell to be good.

Simba i agree with that, similar thing in the gong or port kembla region a few years ago, temp pylons and some sort of loading dock thingy for the ships was there for a few months and creates excellent rights on even tiny swells.

bob_s's picture
bob_s's picture
bob_s commented Friday, 19 Dec 2014 at 8:21am

simba wrote: Possibly a cheap way to create banks is to drive pylons into the sand and let the sand build up around them,surprising how well and quick it works as in the coffs harbour sewerage out fall which was temporarily built to lay the pipes out to sea and the sand that formed up around the pylons or near them was awesome.Probably only need them a meter or two depending on depth.That was on an open beach with a lot of sand flow but quite open to southerlies.

Similar phenomena occurred at 9 mile beach Belmont NSW when the outfall pipe was being laid.
The locals observed that it was the continual flow of sand to the end of the trestles by the pumping needed for the construction that created the banks. Whilst the sand was being pumped the banks improved . When sand pumping stopped the banks dissipated. It was the major secret surf location for a while -out in the middle of nowhere .

bob_s

aidandavies's picture
aidandavies's picture
aidandavies commented Saturday, 27 Dec 2014 at 9:59pm

Why not Perth as a trial location?

the (frustrated) surfing masses are there, if the local govenment / council are open to ideas? the swell is sufficient during the winter months; I've surfed south straddie on minimal swell and its almost always fun and it some cases epic..

I'm a final year engineering student and I'm looking at artificial reefs, specifically for Perth, as my thesis topic.. I will be modelling the swell / structure interaction using fluid dynamic software, looking to optimise design for a specific site (scarborough is ideal is many respects).

would love to hear more opinions / ideas / thoughts on the use of offshore submerged structures (possibly semi inflated pods to reduce cost?? the buoyancy force is massive but possible manageable?)

Engineering student currently involved in research and modelling of artificial reefs
contact: aidandavies@gmail.com

prothero's picture
prothero's picture
prothero commented Saturday, 27 Dec 2014 at 11:50pm

ive been surfing Triggs for over 30 years....and have pondered the idea of putting reefs in for a longgg time..Would it work ? I believe so. Cables was always a bad idea, Triggs and Scarborough however would work, SW swells consistently squeeze between garden island and Rotto and hit this stretch, not raw swells of the south and north, but swells do get in there. Slowing the swells down with underwater structures would lesson erosion on the coast and provide habitats for fish and places to dive in the flat spells. Quality surf, quality diving in clean Perth waters, sounds a goer to me.....

Prothero

aidandavies's picture
aidandavies's picture
aidandavies commented Sunday, 28 Dec 2014 at 12:06am

Prothero,

You're right, the swell window for cables is so small with prevailing conditions in the area.. but with the right N swell (less than a few times a year as I'm sure you know) it does get fairly good.. that said, and armed with only limited knowledge at this point, i think the idea of something submerged to refract the straight'ish SW swell that hits Scarborough / Trigg might be a better, creating A frames and peaks similar to D-bar, Booj, South Straddie, even Lefties has a similar set up..

The Cronulla event in 2012 due to strategic sand placement seems to me one of the best results of intended surfing enhancements.. why not investigate a permanent structure of this type?

Engineering student currently involved in research and modelling of artificial reefs
contact: aidandavies@gmail.com

uncle_leroy's picture
uncle_leroy's picture
uncle_leroy commented Sunday, 28 Dec 2014 at 2:51pm

Thread was first posted May 2013
Does anyone know if the Government is still being pro active in possibly developing man made/groomed waves with shape ?
Spend a bit of time in Perth with work, be good to surf a nice little peak in the winter time

Clam's picture
Clam's picture
Clam commented Wednesday, 26 Jul 2017 at 10:40pm

Talking about swell directions for perth ,
It seems that its predominantly wsw-wnw at cottesloe buoy .
its been 7 months of observations to be able to accurately say that opinion .

http://www.transport.wa.gov.au/imarine/cottesloe-tide-and-wave.asp

nogo's picture
nogo's picture
nogo commented Thursday, 27 Jul 2017 at 10:04am

That is a very rare direction.

Jamyardy's picture
Jamyardy's picture
Jamyardy commented Thursday, 27 Jul 2017 at 10:53pm

I heard when they first built the breakwall at Pyramids there was no dog leg, so the wedge used to break all the way to the beach and was good at times. Before they built the cut it was supposed to be even better ... Dixie lands I think it was called. It's a swell magnet for the area for sure, but straight as most the time.

Jamyardy's picture
Jamyardy's picture
Jamyardy commented Thursday, 27 Jul 2017 at 11:00pm

Cables is a great wave when it works. The same kiwi mob (I think) built one at Kovalam in SW India, surfed there before they put the artificial reef in, good beachy and always a decent size at the right time of year. Heard the reef got partly uprooted but maybe fixed many years ago.

Clam's picture
Clam's picture
Clam commented Friday, 28 Jul 2017 at 2:57am

According to the cott buoy data its not rare , but thats just a buoy . Ive only watched it for the last 7 months though so thats only short term observations .

thermalben's picture
thermalben's picture
thermalben commented Friday, 28 Jul 2017 at 9:14am

Didn't really need buoy archives to confirm this, did we? Anything north of west is rare at best (beside pre-frontal NW windswell), and anything south of west is sheltered (and refracted) by Rottnest Island.  

Craig's picture
Craig's picture
Craig commented Friday, 28 Jul 2017 at 9:22am

What Clam has pointed out though is that W/SW groundswells actually come in W/NW on the buoy, wrapping around Rotto?

thermalben's picture
thermalben's picture
thermalben commented Friday, 28 Jul 2017 at 9:43am

Absolutely, that's the same as S swells coming in SE or E/SE on the Gold Coast buoys. 

Craig's picture
Craig's picture
Craig commented Friday, 28 Jul 2017 at 10:03am

Yes true.

Clam's picture
Clam's picture
Clam commented Friday, 28 Jul 2017 at 10:37am

Thanks craig, for the backup explanation , and ben for the comparison.
Its going to be interesting to see how it fares in spring/ summer .
Since mid summer its averaged over 50% north of west direction , imo .
Might be different when the counter current starts from the south in spring / summer .
Mandurah directional buoy averages west direction too , interesting case study .
http://www.transport.wa.gov.au/imarine/cottesloe-tide-and-wave.asp

Clam's picture
Clam's picture
Clam commented Friday, 28 Jul 2017 at 12:29pm

1. "Didn't really need buoy archives to confirm this, did we?

2. Anything north of west is rare at best (beside pre-frontal NW windswell), and anything south of west is sheltered (and refracted) by Rottnest Island. "

3. "and anything south of west is sheltered (and refracted) by Rottnest Island. "
________________________________

Thermalben , i cant quite understand what your saying here .
If you could break it down then you might be able to teach me something here .
Both points youve made are a bit too brief to get the gist sorry .
Thanks in advance.

Clam's picture
Clam's picture
Clam commented Friday, 28 Jul 2017 at 12:45pm

"What Clam has pointed out though is that W/SW groundswells actually come in W/NW on the buoy, wrapping around Rotto?" Craig .

Thanks craig, Not only that but swell direction on buoy shows wsw-wnw , including west .
How would you explain the due west direction ?
It seems to be a balance where sometimes* it comes in more to the sth or more to the north , of west .
Certainly can be both directions all at once too . ( *On the directional buoy )
Considering the direction of the mandurah & rottnest buoys stats it is actually no suprise cott recieves mostly wnw direction .
And then theres the leeuwin-current and the counter current to factor in .

http://coastaloceanography.org/

http://oceancurrent.imos.org.au/sst.php

Clam's picture
Clam's picture
Clam commented Sunday, 13 Aug 2017 at 8:34am

"How would you explain the due west direction ?
It seems to be a balance where sometimes* it comes in more to the sth or more to the north , of west .
Certainly can be both directions all at once too . ( *On the directional buoy )
Considering the direction of the mandurah & rottnest buoys stats it is actually no suprise cott recieves mostly wnw direction .
And then theres the leeuwin-current and the counter current to factor in ."

Just Reposting the initial question, hopefully someone weighs in with a theory .

http://www.transport.wa.gov.au/imarine/cottesloe-tide-and-wave.asp