Sand Banks

Great question Nick. This is well outside my area of expertise but I suspect underlying rock structures have a lot to do with it (providing an anchor point for gutters and banks), as well as the granularity of the local sand. I'll see if we can track down someone specialising in this area to comment.

I don't know much, but tidal currents varying with topography can be significant I think.

I'm no expert either but in some parts wind flow over a sand source( sand hill or whatever) into an area your surfing in my oppinion helps sand build up.
Say a west facing coast that I lived near last year with a marina wall on the north end of a beach. The sand would build up covering lots of rocks and build a nice bank In the nthern corner.
I'm sure what helped was southerly winds in summer and flat to tiny surf. By June the sand was gone and the beach was rocky again. (Big swells and more ne winds)

Another spot where I live now has a groyn behind a port.
Dredges suck sand outside the port for the large ships which guides the swell onto the groin area instead of the port.
What's great about this is that the groin over summer is in a spot where the sw to sth winds blows sand onto the groyne area....edited for discretion.
Other things can effect banks such as creek or storm water outlets, rain, and swell direction and size.
Size can make good banks it can also wash away sand. But as I said I'm not an expert on that and a lot of it is pretty confusing. I have a feeling swells from two angles over a short period of time create peaked banks as do outer shoals peak up swells into a frames sometimes.

Apart from bottom features and depth running out to sea.

The length of the beach i think has an effect.

Shape of the beach, steepness etc and whats beyond the high tide line, reef or dunes etc.

With Victoria beach's all the ones that face directly into the predominant swell direction also seem to have rip type beachies, Kilcunda, Woolamai, Gunnamata, Johanna….i think a big reason for this is the lack of variety of swell direction, unlike say the east coats of Australia beaches where you get a variety of swell direction from everything from very South to very North and get currents that often sweep south to north or north to south, in Vic the swell hits it maybe 95% of the time straight on so the water gets pretty much pulled straight back out forming those rip banks.

You can actually every now and then see this effect happen on some east coast beaches, like when i lived on the Goldie, if you get a good run of straight east swell you can actually start getting rip style beaches form up and the outside banks start linking up with the shore banks and you get rips pulling back out to sea instead of shore long sweeps, then as soon as a SE swell hits it washes a big gutter between the shore and outside bank.

Then in Victoria there is also a wind factor all winter sand gets blown along the beach generally in a west direction then in summer it gets blown back from the east.

But i think the bottom structure is right up there, my local beach Woolamai although its pretty much appears all sand, everywhere underneath is different depth reef, some reef gets shown every year, but other areas will only pop up once in a blue moon last year an areas of reef appeared that id never seen so going back to the 80's.

Then there is swell size and even swell period that is a factor and again wind direction, for example IMO lots of victorian beaches will get there best banks after a run of small long period swells with offshore winds, off course those are ideal conditions to surf them, but it also seems to create a good bottom shape that even when it goes onshore with a shorter period swell the waves will break better.

Google longshore drift, there are multiple factors influencing the formation of beaches and banks, natural and man made. Some pretty funky formulas involved in working out what's going on. My understanding is that the profile of a beach will change in the short term due to seasonal current and weather changes affecting swash and backwash and long term by erosion, run off and the formation of headlands, deltas, spits etc. Of course anything man made in the littoral zone or even further out also has an effect.

What creates those crappy guttered sand banks?

When it comes to beaches Prof Short is the man.
http://www.ozcoasts.gov.au/conceptual_mods/beaches/ShortJCR06.pdf

Nick,
Check this book chapter,

http://www.springer.com/cda/content/document/cda_downloaddocument/978331...

Good explanation of fundamentals and some examples from your next of the woods.

I wonder if Port Phillip bay is much of an influence for you at Portsea in regard to sand supply? you would expect so, its a big area of water and sand must get pushed in and pulled out and after all they have dredged the bay that could filter down to your area.

To me our banks at Woolamai don't seem to be what they were in the late 80,s-early 90,s, but when i talked to a long time local shaper about it, he convinced me that it just goes through phases and cycles.

There is also the human nature factor that we always remember things better than they were and remember the good days but the average to bad days fade away, also how we surf waves has changed waves may seem slower ad fatter now basically because we surf faster.

That last one's an interesting point ID, surfing faster and differently, hence looking at the waves differently.

Nick Bone wrote:

A very general question which probably has alot viable answers but im just wondering how sand banks actually form up at beachbreaks? What are some contributing factors that lead to bank development?

Specifically, I live on the Mornington Peninsula and at one end we havr Gunnamatta which gets better quality and more consistent sand banks whereas down the other end at Portsea it struggles to form any decent banks.

Is it to do with the bathymetry from beach to beach? Is it the way the coast faces to swell direction. The Peninsula faces pretty much straight on to predominant swells but Gunna and Portsea are angled differently ever so slightly. Is it to do with the minor rock formations on the shoreline which may direct sand flow?

Any insight on this matter would be muchly appreciated! I understand there probably a definitive answer but i would love to hear any theories etc. on it!

Cheers!!

don't agree mate Portsea can throw up some quality banks. had a right here that was epic. plus Spooks has a great bank.

Regards to gunna, first carpark left and right. i think it might be due to depth and bottom reef formation that holds the sand in place. hayfields another example of this as that right is always there just better certain times to another. I lived at Snatches while i was a teenager and notices it had much shallower banks then gunna.

i might be way off but that's my theory.

Bad form VIclb .
I'm tipping people would be angry at you for even mentioning one place , let alone numerous .
Back in the days that I frequented those spots you would been beaten sideways for even thinking about talking about them in a car park let alone the net .
I thought long and hard about talking even indirectly about this topic , reckon I could of filled 2-3 pages . But unless you named the generic examples or descriptions of places then it would have been toohard to define theories .
All I say is longer beaches tend to have banks at either end which are more regular . Places with large Dunal systems and no creek / river or water course will have banks which are defined by the preceding few weeks months of swell , wind etc . But long term ( seasons , years , decades , centuries etc ) that is where the inshore primary and secondary dunes are formed by wind alone .
So I would suggest that the dunes themselves , without obvious reef , rock/ structure , geographical influence or a waterway , will have regular areas that banks form due to near inland dunes directing water to leak out through the water table , to sea . These spots will undoubtedly form / help a strong rip form . With atleast one wave on either side or even two. Generally this happens nearer the middle of the beaches length .
Portsea on the other hand has cliffs in the centre and half /quasi dunal systems at each end .
I would suggest that the central region inland of that beach , that waters trickling down through the water table would tend to flow North towards the bay . Obviously there is a bit of reef structure around the SLSC , but it's very rare to get an exceptional wave there , and most likely reforms .

Just beat me too it Southey..
Viclb, fair enough mention gunna, but the other couple aren't exactly super well known waves.
Be a bit discreet hey!

Gradient to the 20m contour i reckon nickbone. Those reefs can protrude from the seabed and bend swell more. Probably shit waves anyway considering it's a claim coming from vic long boarder haha :p

Nick Bone wrote:

But now it seems Portsea is stuck on groundhog day with sandbars parallel to shore with the occasionallllllllll corner.

Six weeks ago Portsea had unreal banks, that were perfectly visible on our surfcam (see image below). Was like this for about a week if I recall correctly.

mitchvg wrote:

Gradient to the 20m contour i reckon nickbone. Those reefs can protrude from the seabed and bend swell more. Probably shit waves anyway considering it's a claim coming from vic long boarder haha :p

I normally ride hollow waves on my 9,1 longboard also have a 510 egg now as well. I have ridden mals at EP flynns bird rock meanos spooks. beauty of performance mal is you can use it in basically any surf. from hollow reefs/points to grovel rubbish.

that being said i have mainly been riding my egg lately as is nice o be able to crave some waves up.

month a go i was at gunna small waves on my egg and bunch of mals where out there first time i realized how bloody annoying they can be LOL

goofyfoot wrote:

Just beat me too it Southey..
Viclb, fair enough mention gunna, but the other couple aren't exactly super well known waves.
Be a bit discreet hey!

WTF seriously spooks and snatches are very well know i know this as i had to deal with the fraaken crowds every weekend.

next you'll be telling me Miami and paradise are secret spots. get over this secret crap even when i was a local at snatches (i lived on Alison ave) you never own the beach. it's there for anyone and everyone to enjoy.

Totally agree that there aren't many genuine secret spots left but I'm not sure why anyone would want to discuss specific breaks here on such a public forum for any reason.

Even SW doesn't disclose the location on its WOTDs and I think that's fair enough.

Speaking to my Mornington Peninsula mates they say that since the Eastlink & Peninsula Links have been built many more punters who may have otherwise driven to the Island or the West Coast are now heading there way.

The places are well known, sure, but why publicise them?

VICLB wrote:

goofyfoot wrote:

Just beat me too it Southey..
Viclb, fair enough mention gunna, but the other couple aren't exactly super well known waves.
Be a bit discreet hey!

WTF seriously spooks and snatches are very well know i know this as i had to deal with the fraaken crowds every weekend.

next you'll be telling me Miami and paradise are secret spots. get over this secret crap even when i was a local at snatches (i lived on Alison ave) you never own the beach. it's there for anyone and everyone to enjoy.

Why don't you just name every spot on the coast you moron.

god you guys are wankers.... wannasurf? ever heard of it?? think they dont list every spot known to man? anyway think you guys are way to cool for me. hiding known spots on forums yeh mad locals get over yourselves c@ck smokers.

I personally don't have a problem with people naming spots as like pointed out they are all online wanna surf type web sites and in all the guide books, in particular "A guide to surf beaches of Victoria" doesn't leave many stones unturned and goes into quite a bit of detail.

Giving information on current good banks is different though (i don't think anyone did that here) but you see it on social media people bragging about the surf they just had on a good bank even posting pics, and it sucks when guys are checking the surf and you can hear them on the mobil phone telling others so and so is good, that kinda sucks.

In days gone by if you were onto it a good semi hidden bank could stay uncrowded for a few days before the crowd got onto it, but these days your lucky if you get one day, as some people even get on the mobil phone as soon as they get out of the water and feel they need to let everyone know how good it just was on so and so bank….thank god my beach is so tidal and ever-changing.

Some are selfish & some are generous . Sometimes surfing can be dangerous and you might need to be carried to hospital by complete strangers .

Yeah but Indo D and viclb just because they are named elsewhere doesn't mean you should add to the problem.
And caml which one would you be? Would you like all those desert waves that I see photos of you surfing on Instagram named? I doubt it..
When you rock up to a local wave and its packed have you never complained about the crowd, or have you just thought oh that's lucky there's so many people out because now I've got a better chance of getting carried to hospital by a stranger.
Surfings one of the most selfish pastimes there is.

Vic lb your proving yourself the right royal wanker . Nobody likes a self righteous tosser . And it doesn't matter where u live your still a tosser . In the times I enjoyed that region , people didn't tolerate " tossers " like u ...
People just reminded you to be a little more discreet , and you go and shit in their direction . No wonder I don't frequent the water there anymore , because even " new locals " like you are dickheads . Way to shit in your own nest . All I hope is that some " Ol' school " no nonsense guys read this work out who you are and fade you on your rice bubble at every opportunity at all these low key spots you keep talking up as " your playground " , your not impressing any one , loud mouths aren't legends . Best you keep your act local .
PS , I have a fair idea who you are , and if I'm wrong then pretty sure goofy does .

VICLB - honest question mate - did you really never know that long boarders were annoying when you're on a short board ?

Not sure if you're LOLing through sarcasm or embarrassment ?

'Sometimes surfing can be dangerous and you might need to be carried to hospital by complete strangers .'

I'm not too embarrassed to say that I carried the toddler to hospital, although under the cover of darkness. Well, in fact, to be completely honest, I carried homer, the captain, the hero of team newy and MR as well. He was supposed to be helping, but all he did is add extra useless... less weight. As I clean and pressed the jibbering, hapless toddler in and out of the mighty HQ, (simultaneously getting in a workout) I noticed that homer was 'helping', by just clinging to toddler and getting hoisted around like a toothpick by me as well. Just saying... for those that are interested. (Shucksing, bobby machado/rasta head dip, humblesling, non claiming lol).

goofyfoot wrote:

Yeah but Indo D and viclb just because they are named elsewhere doesn't mean you should add to the problem.
And caml which one would you be? Would you like all those desert waves that I see photos of you surfing on Instagram named? I doubt it..
When you rock up to a local wave and its packed have you never complained about the crowd, or have you just thought oh that's lucky there's somany people out because now I've got a better chance of getting carried to hospital by a stranger.
Surfings one of the most selfish pastimes there is.

Goofy they say a picture says a thousand words . Im not posting any pictures on instagram . Im not on the Gram actually . Im just trying to subtly remind the selfish thinker to share more and maybe make friends via surfing . You can actually turn the selfish surfing attitude around by sharing knowledge , skills ,even handing out waves like theyre gifts if u want

Well, you'd think so wouldn't you's. I tried to show surfees how to beef up and become real men, heroes, instead of this sort of pipsqueak lolling, embarrassing debacle, and all they did is spit it, and start squwarking and blubbering uncontrollably.

Anyone in the know can see the sneering, contemptuous look on these poor girls faces. That, 'Whats with the making us looking like a bunch of female, massive, bulked up she men, brick shithouses you fu##!!! smart arse ####!!!! units!!!... #####!!!! Now !!!! off!!!'

Whos the girls on the right ? Looks like a model rather than a surfee

On the far right is the winner of the women's 2015 Margaret River Pro and the 2015 Rio Pro, standing next to the actress Katie Holmes.

Yeah I've seen some footage from the weekend. Looked bloody good!

No-ones done a better job of making consistent sand banks than river mouth training walls.

VICLB because it's on another site doesn't mean you need to spread the word allow things to progress naturally crowds are becoming an issue with rules being ignored creating a dog eat dog mentality on coastlines such as the peninsula.

Nothing wrong with sharing a spot with a mate but this internet age of posting everything online for all to see is contributing to the overcrowding and lack of etiquette at many a break.

Nick Bone,
I'm 54. in the 70's and 80's Portsea had consisent banks, always there when the swell was rideable, would hold 6'plus. 13th used to have banks like Gunna in the days when Beacon had a beacon, the sand used to cover the road in big mounds. Dune restoration is the culprit. IMO it rooted a lot of the Vic beachies. That and that fucken "Seachange" show.

There is no argument here. The Mornington Peninsula beaches used to produce A grade, world class banks on a consistent basis. I am most familiar with Portsea. The 70's scene in summer was dreamlilke. The main obstacle to waves was the size of the swell given the exposure of that coast to large, straight swells; however, at the end of the typical 3-5 day north wind cycle, there was always a good bank or three to enable you to enjoy the end of the swell run. Furthermore, the beach was stable, and relatively flat. There were a few rocky areas either side of the lifesavers clubhouse, but those reefs were permanent, and otherwise there was sand, sand, sand. At low tide you could walk out a long way. I began to notice the gradual destruction of the beach in the early 90's, or maybe it was the late 80's- it is a long time ago now, but I recall during our extended summer break that the work-for-the -dole gangs started rolling up planting the South African marram grass- curse that scourge. Of-course, we thought nothing of it at the time, but when it was combined with the building of fences, and sand became trapped and the whole contour of the beach changed as the result of an artificial build up of sand on the frontal dunes, the party was over. Rocks started to appear at the front of the clubhouse where there had only ever been sand. In my opinion what started to happen was that the speed of retreating water was intensified because instead of running out on a fairly flat surface, it began to run downhill from the massive build up of sand and it gouged the sand off the shoreline and washed a lot of sand out to sea, never to return. I am resigned to it all now, but I used return to Portsea from the mid- 90's onwards and it was heartbreaking. Knowing quality waves are a scarce commodity, I knew that the beaches east of Melbourne, whilst still no doubt producing o.k waves on a reasonably consistent basis, were never going to produce the consistent A- frame perfection that was a common occurrence. I kid you not, in autumn, there would sometimes be up to 5 perfect banks breaking left and right up and down Portsea back beach. The left- hander to the immediate right of the car park was a permanent bank that held very solid swells. Even now you can often see it struggling to offer good waves, but the sand is simply no longer available to cover the reef. I accept that Spooks still produces on a more consistent basis, and significantly, it has not been the subject of fence and foreign grass planting. I kid you not, so obsessed were the environmental quacks from the National Parks service, who regrettably gained control of the beaches in the late 70's , that as soon as one fence was covered over with sand, they would build another, and it would then be covered. I do not think most people have any idea just how much sand has accumulated on the frontal dunes, and how radical the change to the beach over the last 35 years has been. These are delicate eco-systems, and the minute you interfere it is never going to go well. That South-African marram is ugly stuff. It has been planted all around Australia's popular beaches as a result of a moral panic from bureaucratic environmental nut jobs who embarked upon a crusade to save the precious sandunes from the ravages of the recreational beach goer. The dunes at Portsea are/were robust and extensive; there was never widespread entry onto them-most people just walk along the beach or sit on it. What a tragedy, which I fear has been repeated at many beaches. We are not like the northern rivers beaches. The supply and movement of sand is limited. So thanks National Parks, and their partners in crime throughout the relevant time, the Surfriders Association, who I sensed were just a group who used the image of surfing to promote real or faux environmental causes rather than focus on the conditions that would preserve the supply of quality waves close to major population centres. A colleague once described the rivers of sand that used to move up and down, and in and out at Portsea. Alas, it ismore, nor will it ever return. In my opinion, a terrible man-made environmental and complete, yet largely unrecognised,cock-up.

'bureaucratic environmental nut jobs who embarked upon a crusade to save the precious sandunes from the ravages of the recreational beach goer. '

Oh, Oh. Ah yes, thats the 'work' of, as they are officially referred to, 'scientosis bunglitis maximatasi', or as they are commonly known, 'scientists'.

They worked their 'magic' over here too, again, South Africa had a special attraction to them. Now the whole area is plagued with and coated in Lincoln Weed, Box Thorns, and Bridle Creeper. Ingenious.

They were extremely entertaining around Ballina too. Swarms of blithering, microscope weilding nigels, crawling through another bungle, the Bitou Bush jungle.

http://www.environment.nsw.gov.au/pestsweeds/BitouBush.htm

They would place hundreds of kilometres of red ribbon on the bushes daily in an exhausting effort. I felt sorry for them one day, and approached an obvious leader, screeching orders at the other white coats. I suggested that they should just put a ribbon on the non Bitou Bushes, and that way they wouldn't have to use any ribbon or do anything. So they were extremely thankfull and gave me an award (another one). A cane toad leapt on one as they were presenting the award to me, and they all disappeared, excitedly chasing it back into the Bitou jungle.

great to see cane toads being useful to someone else. As youngsters, another Swellnet poster now living near Antarctica and myself, used to tie steel nuts and bolts on their legs and throw on our teachers tin roofs. No animal cruelty here as u were supposed to kill them anyway and we gave them another night of life closer to the heavens and they hopped around noisily but happily all night long.
This was for being put on detention for going to roll call then walking out the gate to catch the 9.10 bus home to go surfing.

Hmm, I wonder if there's a bit of "ahh, the waves were better back then".

I disagree that Portsea always had great banks, which seems to be the agreed position on here. I used to stay in the clubbies clubhouse frequently in the mid-late 70's and then for the next 5 years or so would regularly check or surf at Portsea. I clearly remember some great banks there, between Hueys reef (that rock stack out to the right of the clubhouse) and up to about 100m to the left of the clubhouse. And another often long left the other side of Hueys.

I've never seen any decent waves between the clubhouse and Sorrento.

But I also remember long straighthanders, 100m long sections, no real banks and vicious rips.
I don't think it's really changed much, to be honest.
There were always rocks in the shorebreak - sometimes they were covered with sand, and sometimes they weren't.

And I've seen areas of sand buildup inshore in the last few years, where there's been a shallow bank going out a fair way - it's a very dynamic environment and the sand shifts a lot.

It's the same at first carpark at Gunna - I remember 30 years ago some unreal surfs on a bank in front of the reefs to the right, with a left over the other side of the beach and a big rip between the two. Then they disappeared and there was a v-shaped bank in the middle.

Strangely enough, the banks at Woolamai seem to be quite stable. Yeah, they change a bit but they don't seem to disappear and reappear like the Peninsula beaches. For example, there has always been a right in front of the clubhouse.

Woolamai has marram grass all over the dunes, so I don't think you can blame the grass.

And while I'm on the "it was better in the old days" bit - I'm constantly hearing how it's getting more crowded. Crap. It was just as crowded back then I'm talking about late 70s. A mate quit surfing 35 years ago coz it was "getting too crowded". We'd have to work hard to get an uncrowded surf on the Peninsula (yes, even those "secret spots" got crowds). Bird Rock was just as packed then. We'd look from Steps (back when you'd get changed in the dirt area above the steps) up to Winki and it just looked black like an ants nest with all the crew on it. To be honest, I'm getting more uncrowded surfs now than 30 years ago, but maybe that's because I know where and when to go. I'll grant you that NSW & Qld might be different to down here - something about sun & warmth maybe? ;-)

Not sure about the effect of the grass....but I recall the banks at Woolly when it was just a single lane sand rd to the clubhouse being significantly more consistent than they are now, although the banks there would still beat Portsea / Gunna every day of the week.

There was a reef that had a great left and and right set up fairly close to shore. The left was very good. Nearby a very minor creek flowed onto the beach but only after winter or heavy rain. Very small creek it was. Developer sub-divided the land above the beach into 2 and 3 acre lots and with the roads and drains the little creek dried up and now only flows after super heavy rain and then only having a fraction of the water flow. The reef is still there but the sculptured sand around the reef is long gone. No more waves just a shore dump.

Yo Crip, yes it's true, my memories of the 70'S and 80'S are clouded in the mist of age. I was very handsome, I ripped big waves, I won every fight, chicks dug me and my hard on was like a brick of cement.
Nowadays I'm wrinkling,receding, I mostly ride mals, a chick could punch the shit out of me and my cock has died. But I'm telling you the banks were better at Portsea back then, I was there!

crip wrote:

And while I'm on the "it was better in the old days" bit - I'm constantly hearing how it's getting more crowded. Crap. It was just as crowded back then I'm talking about late 70s. A mate quit surfing 35 years ago coz it was "getting too crowded". We'd have to work hard to get an uncrowded surf on the Peninsula (yes, even those "secret spots" got crowds). Bird Rock was just as packed then. We'd look from Steps (back when you'd get changed in the dirt area above the steps) up to Winki and it just looked black like an ants nest with all the crew on it. To be honest, I'm getting more uncrowded surfs now than 30 years ago, but maybe that's because I know where and when to go. I'll grant you that NSW & Qld might be different to down here - something about sun & warmth maybe? ;-)

Mates and I have had this discussion quite a bit over the last few years & we agree with the above with regard to our neck of the woods. What has changed is how we cope with the crowds. Older blokes cannot really compete with blokes 20 years younger hence we get heaps less waves than in the past & this is what makes things seem different. That's our theory anyway.

Not sure about the "I'm getting more uncrowded surfs now than 30 years ago" bit though unless one really surfs crap. But so long as you're having fun that's all that matters.

Ha ha Adam, I wished I didn't read that at work. Lucky I wasn't drinking my coffee at the time coz it would have gone all over the keyboard!
:-)
BTW, I totally sympathise.
Coming back to Portsea, I wonder if all the development up in & behind the dunes between the Back Beach Rd & Sorrento has affected the banks?

Im undecided on the quality of surf issue but there is no doubt that it is definitely more crowded down here on the Island, which only makes sense as since the late 80,s early 90,s our population has more than doubled and the road to Melbourne is so much better, as a grommet there was basically no one my age surfing now kids of all ages are surfing the internet forecast etc i think has also changed things for the worse :(

Baconeater wrote:

Not sure about the effect of the grass....but I recall the banks at Woolly when it was just a single lane sand rd to the clubhouse being significantly more consistent than they are now, although the banks there would still beat Portsea / Gunna every day of the week.

I did think the same and my theory was that with the old road they use to grade it and push the sand over back onto the beach, but when i talked to an old timer in the know, he told me they also use to take truckloads of sand away.

Crip, I am not suggesting Portsea was always rideable. There was the regular east-coast lament as we pondered the capacity of the reefs across the Rip whilst observing classic long lines of swell as they closed out the entire beach. But Portsea did produce top quality banks on a consistent basis, and often they would last for an extended period, and reappear in the same place. My account is based on close observations that have been made over a 40 year period. Also, my views are shared by lifetime residents with whom I have had frequent conversations over the years, and who shared my alarm as the changes to the beach became apparent. The beach, and others like it, has radically changed over the last generation and a half. When it was stable and endowed with plentiful sand, and when the swell was small to moderate, body surfing was a family activity. There was never any worry about the rocks, because there were very few. When the rocks started appearing where there had never been any, we initially expected them to be quickly covered again by the shifting sands, but they just became more exposed in depth and width. These days the clubbies only have a very narrow area at any one time where they can place the flags. It was always a treacherous beach because of its exposure to swell, but now there is the added danger from exposed rocks, not just on the shoreline.
You cannot interfere with sand dunes to the extent that these dunes have been interfered with and not affect the basic dynamics of sandbank formation, which relies on movement of sand from dunes, particularly from the frontal dunes. Dune stabilisation renders the dynamic and shifting dunes impotent. The dunes at Gunnamatta and Woolamai are not early as high as at Portsea and it may be that the banks at both beaches are more consistent today, but I expect they do not approach the consistency and quality that they exhibited before the cursed SAfrican marram was planted and fence upon fence was erected to stabilise the dunes.