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Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 7:06 pm
by crabmeat thompson
Thoughts? Will this make banks?

banks for dayyyyyys?
The $13.9 million Beach Nourishing Project aims to increase the amount of sand on open beaches which are vulnerable to erosion caused by powerful cyclones and wild surf.

For the next 16 weeks crew on the Balder R hopper dredger owned by Danish company Rohde Nielsen will work all hours dredging tonnes of sand from deepwater to the surf zone.
“This project involves dredging three million cubic metres of sand from deep water offshore sand supply areas and relocating it around the wave-break zone,” Cr Tate said.

He said the barge would either dump sand from the bottom of its hull or by “rainbowing” the sand from the vessel’s hull.

http://www.goldcoastbulletin.com.au/new ... a3eeeec292

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 7:16 pm
by alakaboo
I did some of the early work for that project.

Depends how they do it.
If they dump it evenly along the coast then no, if it is uneven then hells yes.

It's a temporary sand plug, but on a much larger scale than the experiment at Cronulla.

The plan we worked on had them creating a series of mini sand engines/sand motors like in the Netherlands.

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One down near Miami, one near Broadbeach, maybe a third.
The dredge is a little limited by draft to get close enough to make the banks perfect, but it should help for a while until it gets straightened out again.

More info here http://www.goldcoast.qld.gov.au/mobile/ ... 38539.html

Looks like the Palm Beach part got added on when the reef plan fell over.

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 7:34 pm
by steve shearer
sand put on the beach and then washed into the surf zone tend to make the best banks, but sand "motors/engines"....I haven't heard that term before Boo, they look staggeringly effective at creating surf......looks like you could create a mini-skeleton bay.

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 7:51 pm
by alakaboo
Yeah basically.
Can't find the best videos of the one in the Netherlands but there is a bit of footage on here
https://vimeo.com/42534944

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 8:02 pm
by Beanpole
So if you, say, wanted to make a marina somewhere you could just create a temporary sandbank and then put the rocks in place?

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 8:22 pm
by alakaboo
Yeah, but nah.

Re: Shearer. Boo. Come in here

Posted: Thu Jun 15, 2017 8:25 pm
by Trev
Beanpole has just created a whole new conspiracy theory.
Let's hope Tom Tate doesn't think of it.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 7:07 am
by carvin marvin
alakaboo wrote:
Thu Jun 15, 2017 7:16 pm


It's a temporary sand plug, but on a much larger scale than the experiment at Cronulla.

Is there someone on the team who understands the theory behind Andrew Pitts offshore sand slug.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 7:21 am
by carvin marvin
Why not finish the Narrowneck reef, there is a sandbag foundation already there.
The reason they could not make it shallow enough was because the Mcquade dredge is a bottom dumper and cannot work/open up/move away in shallow water.
With the 'rainbowing' sand pumping technique they are using this time they can now make the Narrowneck reef shallow enough to create waves.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 7:30 am
by alakaboo
It's not a very complicated theory.
Put sand in a pile rather than spreading it evenly, let the waves make it into a bank.

I'm not on the project anymore but when this was first planned more than 4 years ago there was a lot of discussion about it, and the coastal engineers on council and those advising them are all across Andy's work.

That's not the reason narrowneck was made too deep.
It was last minute liability jitters.
There is a separate project to improve/repair the reef.
http://www.goldcoast.qld.gov.au/mobile/ ... 39934.html

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 7:48 am
by carvin marvin
Thanks for the info.
Fantastic news that they are going to complete the Narrowneck reef and use sand filled geotextile bags which will be more permanent than pumped sand.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 9:39 am
by crabmeat thompson
there is a sign up at the end of street saying the palmy reef project will commence in 2018, after the 2017 nourishment program.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 1:56 pm
by alakaboo
We'll see.
It's very expensive for a small stretch of coast, and not super popular.
It'll be one of the first things dropped from a tight budget.

They're going to dump a buttload of sand off Palmy, at the same time as dredging to figure out where the reef should go.
Doesn't make sense to me, it'll invalidate much of the modelling work they've already done.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 2:38 pm
by crabmeat thompson
alakaboo wrote:
Fri Jun 16, 2017 1:56 pm
We'll see.
It's very expensive for a small stretch of coast, and not super popular.
It'll be one of the first things dropped from a tight budget.

They're going to dump a buttload of sand off Palmy, at the same time as dredging to figure out where the reef should go.
Doesn't make sense to me, it'll invalidate much of the modelling work they've already done.
Boo! Tell them I wanted a deep offshore reef in order to refract swell into neat a-frames from the stretch of the last rockwall at 23rd and talle river mouth.

tell them this.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 2:59 pm
by carvin marvin
Creating an underwater valley {yellow line} off a beach out past where the waves break, running west to east will create peaks either side, in other words you can create a surf break by removing sand and dump the sand elsewhere to create another surf break.
Image

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 3:16 pm
by alakaboo
No, you can't on a sandy bottom.
Try and make a sandcastle that lasts past high tide next time you're at the beach.

That's what they're doing, crabmeat!
400m offshore, enough to bend the lines.

Tate is convinced that good beaches and surf bring tourists (he's right), so he's throwing cheques at the coastal engineers and letting them play.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 3:52 pm
by tootr
A tangent but there was some noise about "not enough" being done to save that beached whale at sawtell.
Apparently it's really easy to dig a channel through a shallow sandbank in 4' of short period slop.

Re: Shearer. Boo. Come in here

Posted: Fri Jun 16, 2017 5:15 pm
by foamy
I believe geobags are going to be the glorious future to mildly improved surfing conditions (my ignorant gut feeling), but the last time I mentioned it alakaboo was quite sceptical and I really know very little about coastal engineering.
foamy July 19, 2015 wrote: When I stand on the geotextile groynes at the Cotton Tree end of Maroochydore, I think there must be a way to use them to create good surfing conditions. Apparently, sea life quite likes them as well.
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