Littoral Feast or Famine
Right now, Australia has its own version of severe inequality playing out in front of our eyes.
Yet it's not income inequality or anything to do with class or privilege that's determining our fortunes. It's sand inequality.
You see, every sand-bottomed pointbreak on the north coast of NSW and south-east QLD has not only an abundance of sand but in most instances it's impeccably formed too. If locals aren't calling the sand the best ever then they're marginally qualifying it as the best in ten years, best in twenty years etc etc.
Swellnet recently ran an article on the surfeit of sand at The Pass, while surf camera and video footage shows Rainbow Bay is similarly stacked, then there's the reports of a beach below the rock line at Crescent Head, not to mention the many other pointbreaks that discretion prevents me from mentioning online.
Rainbow Bay (Shield)
It's no coincidence that when the sand stacks up on one point, it stacks up on the others too, as they're all influenced by the same set of coastal processes and climate drivers. A real time example of interconnectedness.
The sand on the far north coast has been fed by a return to average rainfall over the last three months - something not seen since 2017 - that's increased the sediment load from river run-off and ultimately finds its way onto the beaches.
Crucially, however, the sand isn't being distributed equally along the coast. In general, the surplus sand is sitting on the lee side of points while the wider expanses of beach, particularly the southern ends, have been buffetted by an above-average winter of waves with many swells coming from the eastern quadrant.
The contrasting fortunes is most keenly observed at Byron Bay where the sand at the aforementioned Pass is waxing ever outwards, while just half a kilometre south at Clarkes Beach a cafe is metres from falling into the sea.
After this week's swell, Beaches cafe and restaurant is now five metres from the slump zone with Phil Holloway from Byron Shire Council telling the ABC: "If it's not attended to, without the replenishment of sand or some other intervention, obviously there will be issues with the cafe."
According to longtime local Mark 'Mono' Stewart at least part of the problem at Clarkes owes itself to rainwater runoff. Though the recent cluster of Tasman Lows bringing an extended period of large surf and high rainfall have accelerated the problem at Clarkes.
The disparity is best illustrated at Byron Bay where Wategoes and The Pass are choked with sand, while Clarkes Beach has eroded back to rock (Google Earth scan taken 29/07/20)
Other places not reaping the sand windfall are Stockton where Newcastle City Council sandbagged parts of the beach following storms earlier this year. The reinforcements, which were placed adjacent to the cafe and caravan park, held during last week's barrage, however the exposed beach to the south lost two more metres of sand. Newcastle City Council has developed a coastal management plan for the erosion at Stockton - it was written in 2009 and eleven years later is yet to be acted upon.
Most newsworthy was the recent erosion at Wamberal on the Central Coast. In mid-July, the combination of a large south-east swell and high tide caused severe erosion, resulting in the partial collapse of two houses and the forced evacuation of thirty more. All the damage is on Ocean View Drive where a number of houses collapsed following similar conditions back in 1978.
Solutions have been investigated but to date the burden of cost and negative side effects have stalled progress. One of those solutions is the construction of a seawall which, if it were built, would spare the houses behind it but almost certainly stop sand from accreting in front of it. In short: there'd be no beach.
Many East Coast beaches were eroded during the recent storm cluster, not all of which made the news. At McCauleys Beach, just north of Wollongong, the waves eroded back to brown earth at the south end, while the north end was stripped of sand. Above the beach, a real estate agent optimistically advertises the sale of a waterfront house and the vacant lot next door. The vacant block was once a tennis court at street level but the land now slumps down to the tide line.
Macauleys Beach, Thirroul, looking north and south, stripped of sand in either direction.
For surfers, our knowledge of sand usually starts and stops with wave quality. Are the banks good or not? But sand serves a far more valuable service as it protects the coast during storms. Between swells, sand builds up on the beach and foredune, only for it to be taken during periods of high wave energy. The sand is transported to sea where it acts as a barrier, a 'storm bar', mitigating wave energy before it hits the coast. Then, when the swell subsides, it again accretes on the beach and the cycle continues.
The cycle can be interrupted in two ways. The first is when hard structures are built on the foredune, either locking the sand away or interrupting its movement to the wave zone and back. Wamberal is a classic example of this.
The second way the cycle can be interrupted is when the storm frequency increases and sand hasn't had a chance to return to shore. When that happens any subsequent storm will be attacking the coast without its natural defences in place. Examples of this are the storm clusters of May and June 1974, and June 2007. Craig has written an article on clusters here.
Many locations on the East Coast currently have their defences removed, which makes them vulnerable in the coming weeks. At present, another Tasman Low is forecast to impact the coast next Monday. With its strength and location yet to be determined, residents of many coastal properties will be nervously watching the wave models.
Meanwhile, surfers on the north coast pointbreaks, the beneficiaries of the current sand inequality, will also be watching the storm and hoping for an altogether different forecast.
Comments
It's funny, we've now had clusters of clusters of storms, but beach width almost everywhere, apart from that rocky corner at Clarkes is in an accretive phase.
and still so, so much sand transport happening. it's insane.
With above average rainfall in July, and potentially another dump early next week, the sand transport up there won't be stopping anytime soon.
half of narrabeen beach is just bare rocks now as well.
South end of my local (a little way north of there) is bare rock too.
Some interesting patches of bare rock in the breakzone too. And then a heap of sand pushed up near the carpark.
Weird banks too.
there's another beach just up from Narrabeen where most of the sand is disappearing in the south end and a large exposed rock shelf is coming back. Makes it pretty sketchy coming back in now, but the wave is getting better.
Well in the day the rock fishermen got great blackies between those rock shelves. Got a painting by my auntie on the wall in front of me, of those rocks down the south end.
What I've read is that north of any rock wall or feature the sand will be eroded. Something to do with that south --> north movement of sand. So don't put in protection walls, you're just passing the problem to your neighbours.
yeah, thats a factor but its also the actual transport of sand in the near-shore zone that is astounding.
I went for a rockfish yesterday thinking the swell had finally died down- it hadn't- and the water was full of these huge clouds of suspended sand, being transported from south to north.
amazing.
Full marks for the pun, Stu.
Thank you!
I tried it out on Ben and Craig and they were both nonplussed.
Perhaps they didn't get it..?
Seems it must have been transported straight over their heads...
I wasn't shore it was very funny, to be honest.
At least you caught his drift...
Well, he delta good hand.
I see the puns are accreting...
Hopefully the erosion isn't an issue at my local, I always enjoy a good runnel long the beach.
Gutter journalism.
Just don’t let it descend to gutter humour...
Mere seconds in it. But Craig ftw
Ha, beat ya. Or should I say 'surf beat' you.
You definitely were the forerunner
Yes!
Shear luck?
Hahahahahah!!!! You guys!
Anyway, I regress.
Breaker! Breaker! 1-9!
Someone needs to tell Benthos jokes are shithouse.
At least everyone's picking up on the salient points.
Very few comments swash with me.
Agree. I’m more into current affairs
This pun war is getting out of hand...
What have I dune!
(ok, that one's really bad.)
Rightio! I actually just laughed so loud I woke the bloody baby up!
And and...
Ah fuck it, I've got nuthin'.
Hahaha I'm deffo getting the drift.
You are definitely getting the drift Westy foreshore.
You can bank on that.
Ha, I just realised someone else had already gotten the drift! So I too have got nothin'.
Which reminds of that saying, I started out with nothing and I've still got most of it left.
And you can take that to the bank :)
Do I detect an undercurrent of sarcasm?
I'll have to scour the recesses of my mind because I don't want to appear abrasive.
Only a matter of time. Nobody loves a pun-off more than zen
That's true Kaiser, don't tell my missus or she'll start to keep horizon me.
I've just had a meeting out the back and the inside information is that this pun-off is at breaking point potentially resulting in a wave of discontent.
Does feel like it’s on the ebb
On the contrary my seafaring friend, I feel the tide has turned and everything is all swell and dandy.
In the short period it may feel like a battle of attrition but long period will be a series of peaks and troughs.
(ha ha- i'm done)
Haha, nailed it!
And Zen wins the pun war.
He does tend to weather the storm of high pressure situations
If the previous storm resulted in a bar, then could you not argue that it’s actually better prepared for the subsequent storm? Ie no early erosion phase as the bar is already in situ?
You'd think that the offshore bar would decrease the energy making its way to the beach, but
- if the sand which formed the bar was initially part of the onshore system and was transported offshore during recent storms; and
- the beach has eroded and/or receded due to the taking of sand to the offshore bar,
then it's likely that a new system with its accompanying storm surge/coastal setup will transfer a greater amount of energy over the bar at high tide to that eroded beach. I understand it that the best protected beaches are generally those with a fully developed dunal system which is able to supply sand and buffer things behind it.
Yeah on further thought it occurred to me that no two systems would behave the same. The storm bar would have set itself according to direction/ period etc and the next system’s numbers would be different, so the defence wouldn’t be as good. Better to reset I guess.
one of the point breaks mentioned in the article actually now has way too much sand stuffed out the back ruining most of the wave as it reforms and bends away from itself for the entirety of the wave. There's actually a left out the back which is half decent!
Stockton Beach might be receding, but we’ve had the most consistent run of winter surf in years. I suppose all the sand washing out from the upper beach is doing at least a measure of it’s job in the nearshore zone. The only problem is that with the predominance of S swells for most of the year, the sand never fully returns to shore - it choofs off up the coast to nourish point breaks apparently.
Whilst I have little love for religion one song that sticks in memory from Sunday School is 'The wise man built his house upon the rocks whilst the foolish man built his house upon the sand.'
No love of religion either Dorrito but yes they knew this a long long time ago. Stay out of the sand!!!... it fucking moves
Stu, I'm not sure that its the rainfall driving sediment load increases from river run-off.
My understanding is that the vast majority of the sand being transported is inshore marine sediment and not fluvial (river) material, which has quite different characteristics and behaves quite differently for transport. The riverine flow might be greater and then have the effect of washing the marine sand out of estuaries which can accumulate during periods of low flow, but I thought the acute contribution of fluvial sediments is generally pretty low except during flood flows.
All that erosion should be a necessary reminder to the good old boys that coastal processes do their own thing and need to be unencumbered by infrastructure, and able to be dynamic to cushion the coast from storm events.
You lucky buggers better have one for me in this next swell - thanks to the systems creating your great waves it's been the worst July and now looking like August in my 17 years down in Vic.
Yo (la) Tango,
I've sent the question off to two people working in the field. Hopefully I should have an answer soon.
Tango is correct, - sediment supply from east coast rivers is a fallacy, adopted from other parts of the world where real rivers deliver real quantities of sand (mainly silt) to the coast. Minimal sand is supplied from East coast catchments these days, the sand is marine sand reworked along the coast. The Clarence river is not the Mekong!
"The Clarence river is not the Mekong!"
Would make a great t-shirt.
Or- "Charlie don't surf (the Clarence)".
"the sand is marine sand reworked along the coast."
But from where does it originate?
We know where it ends up, Fraser Island is the largest sand island in the world, we're not talking about small quantities, so where does it all come from?
Studies by Beasley (1948-1950) and Gardner (1955) identified that the heavy mineral composition of Gold Coast beach sand was not consistent with the locally adjacent source rocks and fluvial outflows. A comparison of the mineral content of the fluvial sediments from the Tweed River with Gold Coast beach sand revealed a markedly different composition. The source of the beach sand has been traced to the New England plateau and Mesozoic sandstones of the Clarence-Richmond basin in northern NSW (Chapman 1981).
Further studies by Roy and Crawford (1977) demonstrated that, like the Tweed, the major rivers of Northern NSW, the Clarence and Richmond Rivers are not presently delivering sediments to the sea nor is it likely that they have during the Holocene. The extensive and actively eroding beach ridge systems between Iluka and Brunswick Heads appear to be the source area for the Holocene delivery of sand via longshore transport to the Gold Coast (Chapman, 1981).
As I was typing Shraz did his homework well, but here's what I was in the middle of....
I think the different beaches and their sediment supplies along the whole east coast have different sources and behave differently in the current sea level/climate settings depending on their location. Beach sand isn't just beach sand and there is considerable variation in its composition across the country and in some beaches relatively close together. A good example is the heavy minerals which make the sand at Bells black and little of it around at Southside.
There has been some good work done in recent years around the concept of coastal "compartments" where sediments are circulated/stored/transported in general rather than the wholesale migration of all sand from south to north. Interesting stuff, and it happens all around the continent.
As far as sources go, I'll look forward to your experts - Andy Short will know it all off the top of his head.
Yeah I get the compartments, or embayments, particularly of Sydney and further south. You've only got to look at the colour of the sand at Avalon/Whale Beach/Palm Beach for instance to realise it isn't part of a larger system. If it was the sand couldn't retain that light apricot colour that stands in contrast to the blonde sand of the beaches north and south.
I am puzzled by the genesis of the sand that forms the conveyor belt further north. Half a million cubic metres round Pt Danger each year, and have done for decades at least. That's an incredible amount of sand and I find it difficult to believe it's coming from local beaches just to the south.
Not saying it doesn't, just, you know, hard to wrap my head around.
Anyway, waiting on further info...
No worries, I think one of the things that is difficult is the idea of the scale of the sand in the system (kilometres of it out to sea), plus the timeframe over which it was created (dinosaur plus plus).
Here's an intro to the compartments concept if anyone is interested - https://coastadapt.com.au/sites/default/files/infographics/What_are_sedi...
Here's a good summary of sand, too:
https://coastadapt.com.au/sites/default/files/information-manual/IM08_co...
yep, mind boggling but we really only notice what's going on near structures like headlands and entrances after events, or projects, there's thousands of kms of natural beach without stuff on the dunes at risk that would be adjusting themselves on longer timescales than we generally concern ourselves with. Plenty of sand there to play with.
More of an Archers man myself, Stu.
Be interesting to know what the relative percentages are between fluvial and inshore marine sediment.
Anyhow thats only one part of a three part process. The other part is the sand has to become suspended, ie enough energy to agitate and suspend the sand in the water column.
Then it has to be transported.
All three parts of the process are firing on all cylinders this autumn/winter.
I did some analysis a few months ago looking at the major outflow events across the Richmond, Macleay and Clarence Rivers and then the flow on of sand to the points in the months following and couldn't find any major correlation but there was some influence.
Would need a much greater study but they do contribute.
Have another go at it with south swell energy instead.
Stu also tried to pin erosion at Clarkes on rainfall 'at least part of the problem at Clarkes owes itself to rainwater runoff. Though the recent cluster of Tasman Lows bringing an extended period of large surf and high rainfall have accelerated the problem at Clarkes.'
If rainfall was supplying excess sand why would that exacerbate erosion? The giant sand slug updrift at the Pass (moved there by south swell energy) is simply acting like a temporary groyne, all that sand will move onto the beach pretty soon, wave by wave.
As for cafes, caravan parks and surf clubs in the erosion prone zone, they are supposed to be temporary, relocatable structures built in areas that other more permanent structures would not (or should not) be approved. Move them. Done.
Will do.
The presumption that rainfall has contributed to erosion at Clarkes comes via a Byron local I spoke to recently. He's on the committee working with council to address the erosion.
His theory is that recent changes to stormwater outflows have prevented sand from building up around the pipes.
I don't know if that's true or not, perhaps I should've have added the word 'apparently' to qualify the statement, however I see the same thing happen here on the Coal Coast after every significant rainfall event, whether it's combined with large swell or not.
Probably an impact there on a local scale but that's a massive amount of sand coming round the corner that's gonna dwarf any little sand bumps near the shorey. Council may have to unbury those stormwater drains come summer time.
Food for thought here, the rainfall connection is probably just a winter ECL thing right?, the same system(s) that bring a lot of rain to a relatively small region (typically) spreads a huge amount of swell energy along much of the sandy east coast which lasts for days and it's effects on points and beaches are closely observed in detail by thousands of surfers. That swell can be anywhere from NE to S depending where you are. My point is, on the larger scale at least, it's probably not the rain (or rivers). It's harder to understand and explain than Rocket-Science.
There is some truth to this. Though I would consider it a minor influence.
Most of the sand we get up this way originates (among other sources) from the central coast area.
Some of it is just crushed up shells of little critters.
Almost all of it began life down south a long time ago. It takes millennia for it to get up.
I asked a coastal expert once re. Clarence River etc, and the above is the gist of what he told me.
Thanks Mowgli.
I still think it's important to recognise that in many estuarine systems the sediment around the mouth and often the lower reaches can be marine rather than fluvial. The marine is often composed of a mix of material derived from different geologic features, plus carbonate-based material from a whole range of fauna. The fluvial material is often much coarser than the marine, and it rarely "bonds" with the marine sand effectively (which is why you can't take sand from one place and dump it at another to nourish an eroded beach unless the sands are very similar if not identical) and doesn't move around in the same way. The only ways I can think of outflow events impacting surf quality would be their hydrodynamic impact, where the actual outflow changes inshore water circulation and swell patterns or the fluvial sediment is deposited in such a way as to impact the movement of water (and hence the movement of marine sand).
But I could be wrong.
Indeed be interesting to see further work.
Very interesting.
Stu's title hits the Spot...
More Sand = Less Waves
Pre Sand Pump -10+ breaks > 4 waves @ 2mins = 1,200 waves/hr
Superbank Bypass -2 breaks Snapper / Kirra > 4 waves @ 2mins = 240 waves/hr
Pre 2000 = 2.7kms of several line ups / 2020 = 1.6km of same line-Up.
Crew can guess how many extra surfers in 20 years from whole world to here.
Pre 2000 WSR was twice the size with 5x the wave choice & line ups.
As Superbank charts straighter & wider robbing WSR capacity & options daily.
The wave loses depth & bio diverse character as it combs over new desolate shore.
Superbank VIP ATM is suffocating the Southern Points WSR biosphere.
tbb is not saying the waves are bad...they're great, but there are 5x less waves now.
Been saying this here for a while that Snapper should be Top 5 endangered wave.
2013 was the last salute to Southern Points (Snapper -LM-GM + Kirra Point)
In other words, the last time the surf engaged iconic GC WSR bountiful seascape.
Snapper is most famous for crowds but also it's Almighty Backwash...
One can see it explode skyward from Burleigh Heads....(North WSR)
https://media.istockphoto.com/photos/unique-huge-backwash-wave-at-snappe...
The sand has smothered Little Mali habitat & now rapidly entombing Snapper Rocks.
Ask! When did a photographer or Vid last display iconic Snapper backwash ?
Cyclone or Bust...almost a thing of the past it is...
The sand is fast devouring GC WSR Emblems ...next to go is > { Behind The Rock }
Pause!
Ok! Let's not panic! The Superbank will still have some generic start point (Maybe)?
Crew can always count on Huey for spitting out Mutations...
So it's all cool then tbb...well just for now it is...but it won't last long!
The Sandman trowelled over Snapper Rocks leaving us with these Snapper Slabs.
New less prominent outcrop has less clout to backwash the wave face skyward
The wash now sweeps across more wave face down the line.(Corrupts more wave!)
https://i.ytimg.com/vi/eXArT8ESCoY/maxresdefault.jpg
Resulting in a cross step with double lip...fast becoming a thick encasing shoulder.
https://brightcove04pmdo-a.akamaihd.net/2728142626001/2728142626001_5849...
https://cdn.nobodysurf.com/video/thumb/5ef51898459b3805604efb37818df632....
Basher'z fav food ...SLABZ (Yummy! Yummy!).
The new shape can be traced back thru 2018...
There is a catch! New Wave mutates from Ramp to Slab it races to warp the Exit.
Depending on the frontdoor step it either > flares outward or folds as a curtain.
The Flare allows Pros to Pimp the Exit with hands behind their Backs.
https://stabmag.com/assets/Uploads/2013/07/_resampled/FillWyI2MDAiLCI0MD...
https://i.ytimg.com/vi/McAeBEob2DQ/maxresdefault.jpg
https://media.apnarm.net.au/media/images/2020/03/24/v3imagesbinf75d80e67...
The Shower curtain is merely a novelty at this stage but will hunt heads given time.
https://im-1.msw.ms/eengine/ce_images/eedfdb7c6f2cb918/8D3A4240_960_640_...
29 / 7 /2020 vid shows Snapper's New Backdoor shower curtain ...
https://www.mysurf.tv/video/6176055130001
The new take off is heavier but way easier with less Backwash.
In other words less are gonna get knocked by backwash...less scraps! Sorry!
Spectators lose the iconic WSR explosive backwash but gain a Mutant Slab...
tbb: Put Snapper on endangered List....Sand is burying WSR real fast!'
Tip! Enjoy the flared slabs while they last...a power ball might knock 'em out!
Can Triple barrel roll those slabz but tbb is now too weak to get to them...bummer!
View from the bridge at least affords a Captain's Call on the Snapper salvage.
Go for it!
There's no decent sand at my local. Just keep on driving.
Before swellnet, there was... the sonnet.
"Look on my works, ye Mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away."
P.Shelly 1818
Tango, re the sand origin at the estuary mouths, classic example are the ICOLLs. While they are open there is a net inflow of marine sand which builds up in the lower reaches and chokes the entrance. before you know it there are calls for dredging to remove the marine sand. When there is a flood event the lagoon breaks out and for a while there will be some great banks out the front, but it is marine sands reworked by fluvial processes.
The river bars on the bigger estuaries will change with flood events but like you say they are still dominantly marine sands.
Geological speaking; 220m years of erosion of Mountains in Gondwana formed the The Sydney Basin that extends over 1 500km from Qld through to NSW.
https://www.ga.gov.au/scientific-topics/energy/province-sedimentary-basi...
The coast of NSW is about 2000 km long and consists of 721 sandy beaches (68%), rock coastline (32%), and more than 185 estuaries.
Add sea level changes, prevailing SE winds and swell & dune disturbance you get alot of longshore drift of sand northward to form peeling points and Islands of sand.
Enjoy
Test
Onya Jordan
Before and after shots of Rainbow Bay.
1980s - when it really was a bay
2020 - and the bay is a sand spit
How's this view of Cooly and Kirra from Greenmount?
This is such an interesting subject guys, but one question remains unanswered for me and that is the human intervention of stabilising the dunes to what cost.would love the view of some of you experts. Cheers
Before many east coast dunes we see today were stabilised they were mined extensively for the heavy metals, who knows exactly how much was removed or what shape they were before. They were bulldozed roughly flat in many areas and revegetated. Slap a caravan park on top, a cafe and a surf club and there you have it! Paradise!
Also, very useful resource: https://ozcoasts.org.au/indicators/coastal-issues/beach_erosion/
At risk of generalising, I've found over the years that the people involved in resource extraction industries, particularly those who operated back in the day, have great difficulty understanding their impacts on the landscape and the biota. Common themes with loggers, sand miners, fishermen and the rest include the endless bounty available, the tiny amount they take in the overall scheme of things and confusion with regard to the quality of the environment before and after the activity of extraction. And the issue of anyone with environmental concerns being taken to speak for all people with similar concerns.
The endless bounty is well picked up in Hardin's Tragedy of the Commons which is an essential read for anyone concerned about the challenges of managing public resources.
The tiny amount they take rarely considers the cumulative impact of all the tiny bits they take, and the other operators take, and the frequency with which they take them. Death of a thousand cuts.
The confusion about environmental quality continues to this day. Harvesters often see a bit of vegetation or a few fish, and think everything is hunky-dory. Rarely do they demonstrate that they understand how the soil profile supports the ecosystem, the functioning of the pre-disturbance ecosystem, the relationships between water and soil, or the interactions between species.
The outspoken greenie mentioned might well have their heart in the right place, as could the harvester, but they're often no expert. They don't necessarily understand the science of things they are concerned about and often don't have the capacity to join the dots.
I haven't read the recent review, but early career experience with the EPBC Act made it clear that the lack of historical regulations that take into account the aggregate impact of each development, it's no wonder our environment has been in a continuous decline in condition on the whole.
If you can find it, try and get hold of a book called 'Black Sands: A history of the mineral sand mining industry in Eastern Australia' by I. W. Morley. It was his thesis and subsequently published by the UoQ. Very good info about the rutile miners who, in many instances, were the first people to alter the beaches of the Oz east coast.
I guess what im asking is the free movement of sand by the wind the rain and of course the tides no longer happens as freely as it used to. Some of the older dudes tell me the dunes were monumental in some places but now their not, could this be having an effect on sand deposits natural flow
You're on the money Llama.
If you want to see how those areas look and behave naturally you need to check out some of the national parks in Northern NSW like sections of Yuraygir NP etc.
Mowgli, I think you will find the sand mining was a lot more destructive than “pretty minimal “. Typically a massive hole was excavated at the rear of the dunes and a floating dredge placed in that hole sitting on the water table . It then progressively mined a strip parallel to the beach. So all littoral rainforest, coastal swamps etc were destroyed before the processed sand was then back filled behind the dredge.
That replaced sand was revegetated but the previous environment was destroyed.
much words
full disclaimer though: I'm just one nonce that almost certainly only knows one small part of the bigger story and thus am surely wrong or only part right about a host of things.... but hey, that's what internet discussions a for! Internet FTW!!!
That is all indisputable, Mowgli. We're all just nonces on the journey, mate.
Mowgli, its arguably all 3. If its a remnant patch that goes along with the 2 trees, it's totally destructive. You can regenerate something, but its not likely to ever be the same. We just dont know the full biodiversity values of that remnant patch, and probably never will, so what regenerates will be some sort of transformed forest - could be good for local biodiversity values, but also pretty worthless and even threatening to surrounding landscapes (weeds, fire, ferals), the latter often termed 'novel ecosystems'. Much of what the post-mine rehab on Cape York Peninsula is. Big issue up there, but largely unheard of - out of sight out of mind
Despite having concrete blocks dropped to protect it, more sand was lost from this house at Wamberal. Image was taken from a video shot on Saturday, so today's waves may cause more damage.
I'm certainly no builder but I can't see any evidence of anything looking like a post that I think should have been in that corner of the broken house... shacks will be shacks though! Huey the cookie monster took a bite!
Some interesting comments about sand movement. The Tweed Sand Bypass webpage has some interesting stats.
Annual average sand transport into Letitia spit 574,000m3 (1995 to 2015)
Annual average sand pumping across Tweed River 453,000m3 (2000 to 2019)
Annual average dredging of the Tweed River 126,000m3 (2000 to 2019)
Sand supply, continental shelf to the shore 1.5m3/m from Clarence to the Goldy (estimate. So maybe 200,000 m3 of sand incoming from just this section of the coast).
One in 20 year storm event on the Tweed River had indicated (before and after hydrographic surveys of the March 2017 flood event) to supply 150,000m3 of sand to the entrance.
Basically it appears that the bulk of the northward flow of sand in the border region is pumped and dredged. However some (small portion) of the dredged sand is transported south of the Tweed. Where does the sand come from, I was taught in school "shells". Rivers do as well, but probably not the majority.
Snapper Dump can be read 3 ways...
* More E/C sand drift resulted in more sand being pumped into Snapper.
* Sand from 1st Fingal /D'bah Dredge Dump is arriving at Snapper
* TSB are increasing Sand Pumping to meet quota.
Monthly Superbank Sand Dump Averages have been kept low.
2018 - 30,000 m3
2019- 30,000 m3
Dredging
https://www.swellnet.com/news/swellnet-dispatch/2019/07/18/tweed-river-d...
2019 -30,000 m3 (Fingal) August
2019- 36,000 m3 (D'bah) August + other East / North drops
As a result of Dredging Trial (Fingal Drop)
Next 6 months sand dumps were half of 2018 /19 Avg....
Sand pumping (Superbank Survey) + Results
https://www.swellnet.com/news/swellnet-dispatch/2020/01/29/the-superbank...
2020 ( Superbank Survey...reveals concerns with Sand Pumping!)
By March the Pumps ramp to high volume...
Snapper Rocks are more buried resulting in Backwash escaping North on wave face.
2020
March 44,461
April... 30,744
May.... 44,836 + 14,400 (Annual D'bah Dump)
June... 59,634
https://www.tweedsandbypass.nsw.gov.au/__data/assets/pdf_file/0018/12446...
Note dredge dumps are (Extra) not "tallied" onto Pump dump calendar!
However they seem to be factored into the post lowering of pump volumes
6th-10th August 2020 Dredging Starts (4-8 weeks) 110,000 m3
https://www.tweedsandbypass.nsw.gov.au/operations/dredging-2020
Aug - 30,000 m3 D'bah
Sept -25,000 m3 Fingal
(Possibly) Again revert back to half Average 15,000 m3 dumps until March 2021
In regard to this report, we may be seeing a mankind boosted natural increase.
Think that's the fairest way of putting it! Happy to be proved wrong...
Snapper is undergoing more unmeasured varied change of less predictable nature.
tbb had better stop there...getting way outta his depth.