Nerang River and Sealevel Rise

Dear Jen
 
Yesterday was the highest tide of the year and the highest for the last 12 months and the photo of the sea level against this old sea-wall, I took this morning at the top of the tide at slack water.
 
We built this wall 48 years ago and the SL is around 300 mm [12 ins] below the step. Last January”s KT was around 200 mm [8 ins] below this step.

During the ’60s and ’70s the king tides always came to the top of this step except when there was flooding and/or sea surge from cyclonic conditions, in which case those king tides came above the step. In recent years the SL has not reached this step…


During the mid ’80s the Southport Seaway was installed which widened and deepened the entrance of the Nerang River to the Pacific Ocean allowing much more water to pass in and out with each tide and as a result the low tides became lower and the high tides became higher but the king tides remained much the same but possibly [if anything] slightly higher. This all reflected the higher tide range in the ocean than in the river.
 
Even with all this extra flow enabling better equilibrium between river and sea levels, the sea levels not only have not increased over the life of this wall [48 years], but have actually gone down.
 
Coinciding with the king tide today was a fresh easterly wind [50 - 59 km/h], a slightly lower than normal barometric pressure [1012 hpa], rain and squalls and therefore some stormwater runoff. All factors that would increase SLs not reduce them.
 
Official tide gauges for Southport are of very short duration.
 
I realise that my benchmark is only a rough guide but if SLs were rising as claimed then they would at least be where they were 48 years ago, not a foot lower.
 
Best regards,
 
Spangled Drongo

37 Responses to Nerang River and Sealevel Rise

  1. jennifer January 22, 2011 at 8:12 pm #

    I request that commentators try and limit themselves to one post each day on each thread and stay polite. :-)

  2. Luke January 23, 2011 at 8:39 am #

    Not if you read Helman’s paper and look at the IPO wiggles in SL. Also you have an eyeballed cherry pick in a system that has major hydrodynamic modification – e.g. sea walls, sea entrance channel, canal estate development, increased runoff from urban sprawl and catchment land clearing. How do all these pluses and minuses play out?

  3. spangled drongo January 23, 2011 at 10:06 am #

    Luke,

    There has heen no change between this wall and the ocean since the seaway was built in 1988 and that has only increased the flow between it and the ocean.

    It is the same story at canal estates just opposite the seaway entrance however they are not as old as this benchmark and go back only to the late ’60s. [Biggera Waters, Runaway Bay etc]

    If the ocean was rising the message would be loud and clear.

  4. TonyfromOz January 23, 2011 at 10:18 am #

    I’d like to add a bit here, also as (anecdotal) perspective from an early resident of the (Northern) Gold Coast.

    Our parents and their young family moved to Anglers Paradise (now trendy Runaway Bay) in 1966, long before the Seaway went in.

    Regular King Tides would spill over the Broadwater, and cross Bayview Street, 2 streets back from the Broadwater itself, and a few times seawater would (just) encroach into our front yard.

    At these times, Bayview Street was closed to through traffic as the road always flooded at Hollywell.

    There was always a rock wall a couple of feet higher than ground level from the Biggera Creek Bridge all the way back to Southport along the Broadwater’s edge, but from the other side of Biggera Creek all the way to Paradise Point there was no rock wall, and the Broadwater would encroach at those King tides.

    That encroachment hasn’t happened since the mid 70’s. That land area is the same there now as it was then, and they haven’t constructed a wall in that area.

    Tony.

  5. val majkus January 23, 2011 at 1:39 pm #

    I also recall a photo of I think the high tide guage at Port Arthur which showed lower hide tides currently; I’ve looked for that photo and the comment which accompanied it but can’t find it and can’t recall where I saw it
    so that’s not very helpful is it

  6. Luke January 23, 2011 at 4:03 pm #

    It behoves you oh Spangled to tell us what the sea level rise IPO adjusted would have been according to the sea level rise experts?

    What 50mm in 50 years with a 100 mm range in IPO signal – so you argument is somewhat disingenuous isn’t it?

    You miss my point about the canal estates and I should add canal dredging – it all changes the buffering though the outflow.

  7. Graeme M January 23, 2011 at 6:46 pm #

    This is an interesting topic. The claims of sea level rise all seem to point on average to an increase. Now sure there are all sorts of things to be considered as Luke suggests, but on the whole… mustn’t it be noticeable at an anecdotal level? It would be interesting to have commenters on all these blogs offering their observations.

    After all, if SL rise is to threaten coastal property and low lying lands etc, SOMEONE must be able to notice it sometime? Otherwise, if the statistical records show a rise but at the coalface so to speak all sorts of mitigating factors prevent it being visible, then is it happening?

    I’ll offer that as far as I can *see*, 50 years of observing the sea at Hervey Bay in Qld shows no obvious change. If anything, the King tides of the 70s which regularly overflowed onto the Esplanade are today lower as they do not do this now.

    Anyone got a contrary observation?

  8. val majkus January 23, 2011 at 6:50 pm #

    the late John Daly has a fabulous post on the high tide at Port Arthur
    http://www.john-daly.com/deadisle/index.htm
    and where’s the rise

  9. Graeme M January 23, 2011 at 7:21 pm #

    Indeed. It’s like my comment on the other thread about the swamping of a “warming” signal by natural variability. It’s all very well to be able to demonstrate mathematically or statistically that there is a worldwide warming effect that will cause all manner of problems, but if normal variations in weather systems and climate can render it unobservable (eg the La Nina/ENSO effect here in Australia) then one must question the science.

    And it’s also somewhat misleading to seize on every weather event as evidence of one thing or the other. The truth is we have no real way of knowing what the trends of the past 5000 years may have been. Sure at the gross level proxy evaluation may give us broad hints, but they can’t tell us at a decadal level. Or at least, if that is claimed, I for one won’t be believing it any time soon.

    History is full of anecdotal evidence of extreme weather events. But none of these necessarily offer any insight into broader climatic trends.

    Sea level rise? Hah! I call BS on that one…

  10. cementafriend January 23, 2011 at 10:53 pm #

    Val, the photo, you are refering to, is in the article “The sea level at Port Arthur Tasmania from 1841 to the Present” by J Hunter, R Coleman & D Pugh in Geophysical Research Letters 2003 Vol 30 N07 p1401. I had a computer crash last year and lost the download site but you may be able to get a copy from Dr Hunter at the Antarctic CRC Uni of Tasmania. They found that the sealevel increase over that time (158 years) based on recordings 1841-42, 1875-1902, 1972 and 3 years continuous 1999-2002 was 0.8mm +/- 0.2mm per year which is considerably lower than IPCC claims and shows up the nonsense of the likes of Flannery.
    The National Tidal Centre of BOM put out a publication “Sea Level Survey 2003″
    In that, one can find that the sea level increase at Bundaberg over the previous 36 years was 0.39mm/year. Some sites notably around Bass Strait (eg Burnie) there was actually a drop in the sealevel of 1.5mm/year over 30-40 years.

  11. gavin January 24, 2011 at 7:24 am #

    Can someone tell this latecomer (Val), we’ve done the John Daly thing to death here?

    Also Tasmanians on the whole are a weird mob as the direct result of their “island” heritage and I should know as a 6th gen with roots on the “free” side of Port Arthur.

    BTW Tas uni and the justice dept did a review on the history of that now “famous” mark after
    John Daly

    Sorry Val; I’m from the original coast watchers in the flat earth society

  12. gavin January 24, 2011 at 7:33 am #

    Cement could be the key word on the issue of SL and Bass Strait with so much sand shifting over time.

    These days it would be hard to find any rock around Burnie that has not been tampered with in the last hundred years but old coast lines are a plenty.

  13. spangled drongo January 24, 2011 at 11:50 am #

    Had to go away on family stuff but thanks for the interesting comments.

    I suspect that, as John Daly suggests, what actually happens with ocean hydraulics, to the last millimeter, is beyond human knowledge but to think we can put a satellite in orbit around a pear-shaped geoid with flat spots that cannot run parralel to its object of measurement yet be measuring this object by bouncing a signal off it, have that object of measurement changing for different reasons by the minute, hour, day, month etc and have heavy shipping traffic traversing that same object, bouncing back false signals, is simply producing a vague signal that is vastly overwhelmed by noise.

    Long term obs at a given spot is an honest way of telling if catastrophe is occurring, to what degree, and then apply Plan B.

  14. spangled drongo January 24, 2011 at 12:02 pm #

    Meant to add that so far nothing is happening [move along, move along].

    But you could make a case for ACO2 being responsible for reducing SLs by causing our ever-increasing biomass to prevent flood runoff.

  15. Luke January 24, 2011 at 6:37 pm #

    So how much sea level rise does AGW predict at your sea wall for the last 35 years ?

  16. TonyfromOz January 24, 2011 at 7:17 pm #

    With respect to sea level rise at this wall, I guess we can only go by what we are told by those who should know, and here I suppose that means, say, Robyn Williams.
    100 metres in 100years, so 35 years from now, I guess that comes out at 35 metres above that bottom step!!!

    Should not that modelling apply in reverse.
    Oh! That’s right, AGW modelling doesn’t work when applied backwards.

    Tony.

  17. spangled drongo January 24, 2011 at 8:16 pm #

    “So how much sea level rise does AGW predict at your sea wall for the last 35 years ?”

    I thought you would know that better than anyone being a CAGWer from way back but whatever piece of string you choose, it seems the real world is heading in the opposite direction.

    Could Nils be right after all?

    ‘Orreurs!

  18. gavin January 24, 2011 at 10:29 pm #

    SD; how do we know you actually measured those old KT’s?

    I reckon getting a fix on the average SL is more subtle than chalking the sea wall during some big event

    Now for our average stooge, it’s often possible to photograph the barnacles, ie find the top of solid emcrustation lines both old and new and thus be less dependent on KTs, storm surges etc.

    How old is that rough limestone pattern that outlines former out crops of shells?

    C’mon SD we can’t see your younger finger print on that set of steps!

  19. Luke January 24, 2011 at 10:55 pm #

    So let’s get this amazing bit of hypocrisy right – you have no idea what sea level rise is predicted for your location?

    And you have no data except the odd quick glance at the wall.

    Amazing stuff Spangled.

  20. spangled drongo January 24, 2011 at 10:57 pm #

    gavin,

    Just think! living in Tassie all those years and you didn’t keep tabs on the isle of the dead.

    You really slipped up there!

    But give us a break! I only posted this because asked for a photo. Now you want me to build the bloody Tardis and get you photos from the past!

    I haven’t got evidence but I’ve got lots of witnesses.

  21. spangled drongo January 24, 2011 at 11:04 pm #

    “So let’s get this amazing bit of hypocrisy right – you have no idea what sea level rise is predicted for your location?”

    What hypocrisy are you talking about?

  22. Luke January 25, 2011 at 7:36 am #

    Come on Spanglers stop obfuscating – put up your “AGW suggested” number.

    The reality is that you don’t have one do you? So you’re simply handwaving.

  23. spangled drongo January 25, 2011 at 7:49 am #

    Luke,

    Are you talking about the IPCC prediction or what?

    And what has a prediction to do with observation except be a comparison?

    Even more “definite” than predictions are the satellite “measurements” that assure me that over this time, SLs should be around 150 mm higher.

    Except that they are 300 mm lower. Around 450 mm difference.

    Bit of a discrepancy, wouldn’t you say?

  24. spangled drongo January 25, 2011 at 7:59 am #

    And luke, I’m not claiming that SLs are falling even though they strongly appear to be.

    I’m only claiming as a result of what’s been observed here for the last half century and how water generally seeks equilibrium in spite of how different weather cycles affect SLs, that this old world will be there for us for a while yet.

    Now, what’s your point about SLR predictions at my seawall?

  25. val majkus January 25, 2011 at 3:46 pm #

    i’ve just arrived to rescue my mother from a snake attack (my mother is blind) and found 2 blue tongue lizards instead corvorting on the lawn
    this is from Toowoomba urbanites
    I’m used to blue tongue lizards but have never seen two together
    and my experience is based on outback childhood
    Jennifer what do I do; where do they get water from – can you write a post please

  26. Polyaulax January 26, 2011 at 12:42 pm #

    Compilations from Jason and Topex/Poseidon satellites suggests the Spangler’s observations make sense for his locale. SLR in the area from Fraser Island down to Yamba suggest no rise has been observed over the period of sat record from 1993,while coasts on either side of that have seen rises.The sea is a mysterious lumpy thing. It is rising in toto,but local and regional conditions vary widely. Absolutely nothing can be extrapolated from Nerang anecdotes.

    With an IPO change,I do wonder whether SD’s step will be tested over the next decades,though.

  27. spangled drongo January 26, 2011 at 4:48 pm #

    Poly,

    I really expected to see a rise this time because of that neg IPO which always brings with it somewhat stronger tradewinds and other strong onshore winds influenced by Coral Sea lows etc., those same low BPs and sea surges also creating local SLR.

    I’m sure if the neg IPO hangs around for 2 or 3 decades, those old levels will be exceeded.

  28. spangled drongo January 26, 2011 at 4:53 pm #

    “Absolutely nothing can be extrapolated from Nerang anecdotes.”

    Would you still say that if it was a foot higher rather than a foot lower?

  29. Polyaulax January 27, 2011 at 9:56 am #

    Yep. It’s no reflection on your observational skills. Nothing can be surmised about global-sea level from one data point.

  30. spangled drongo January 27, 2011 at 10:37 am #

    “Nothing can be surmised about global-sea level from one data point.”

    I can’t believe that an intelligent person like you Poly, said that!

    Water that is connected tries to find equilibrium.

    Over the length and breadth of the planet this connected water [called the ocean] tries to maintain a level. It does not ever achieve this at any one time but it averages out .

    That’s why it’s called sea LEVEL!

    When a point of this sea level is observed continuously over nearly half a century against a fixed object to only decrease [and by a very obvious amount] it is a reasonable to assume that SLs are not rising.

  31. Polyaulax January 29, 2011 at 8:32 pm #

    SD.the ocean is a ‘very big thing’.You yourself note that sea-level is anything but level,given the variations in temperature,wind conditions,tidal factors,variation in air pressure and different average local air pressures. Then geostatic,isostatic issues have to be detected and factored. After all these factors are recognised,the global tendency is for rise.Even when the majority of measuring points show a rising trend,some of the remainder can be static or even go backwards for periods,and those that show long term rise of course have their own signal variability around that trend.. For your one historic observation point,there are many other longer term points,such as the marks at Port Arthur,and in the Falkland Islands in 1841/1842 by James Clark Ross that show unambiguous long term rise,but which may have shown static or negative trends for considerable periods on the journey

    The Australian Baseline Sea-level Monitoring project has been running highly calibrated gauges since 1992.Unfortunately they have no device in your area,which as I said,the Jason-Topex/Poseidon satellite data with inverse barometric correction shows to be in a region of pretty tiny sea level movement.The closest stations they do have ,one near Sydney,the other near Gladstone, show so far a rising tendency,but the amount varies annually and sometimes temporarily reverses.

    Australia is on the move drifting northwards as most people know,but it is also rising at 0.3 to 0.4mm/year which is enough to affect slow SL rise trends.Maybe this is a factor in SE Qld/NE NSW,combined with regional weather tendencies suppressing clear signs of long-term rise. As well,since you are well within a modified estuary well back from the sea with changes to the seaway exit,you have to ask how all those factors mask any maritime signal. What other dredging and re-engineering has happened in the square kilometer around you?.Really,could you detect a 0.5mm/year rise in SL with anecdotal observational practises,given the huge noise of short and medium term variability?

  32. spangled drongo January 29, 2011 at 9:59 pm #

    Yes Poly,

    Sydney is showing a couple of inches a century but not much seems to be happening with SLR in the short term:

    http://kenskingdom.files.wordpress.com/2010/10/sydney-noaa.jpg

    In the longer term there is probably even less happening:

    http://www.dailymail.co.uk/sciencetech/article-1066712/Uncovered-lost-beach-Romans-got-toehold-Britain.html

  33. Polyaulax January 30, 2011 at 10:28 am #

    SD,interesting links. The Sydney data matches well with the Port Kembla site…maybe its the same?

    The Roman site article mentions that the estuary has silted ,hence the shoreline moving seaward over 2,000 years.Also much of southern England is experiencing post-Ice Age isostatic rebound.

  34. spangled drongo January 30, 2011 at 12:07 pm #

    Poly,

    The north is experiencing the rebound but the south is sinking:

    http://www.independent.co.uk/environment/climate-change/flood-risk-raised-as-south-sinking-faster-than-predicted-457155.html

    Combine this with the fact that the Roman landing was 2 miles up the R Stour and SLs there in the last 2,000 years must have gone down around a net 2 meters.

    If any SLR was happening in that NOTW, London would be in real trouble, yet they don’t seem to get it.

  35. Polyaulax January 30, 2011 at 1:11 pm #

    Sorry,SD got my isostacy a*** about,but it’s not important.

    But I think you underestimate sedimentation caused by massive deforestation that the Romans would have initiated. They were a high-tech and large invading group with resource demands and land-use practises several orders beyond what tribal Britain had ever seen. They were at it for more than three centuries. All the media filtered accounts mention siltation.

    There are lots of examples of infilled estuaries in southern England with consequent abandoned/relocated shorelines and settlements

  36. spangled drongo February 1, 2011 at 9:41 pm #

    Here is a graph I just got from Griffith U of the official tide gauge data in my area for the last 23 years.

    I suspect from the break in data that it is from two different gauges but it shows a drop from the year 2000.

    http://www.bom.gov.au/ntc/IDO70000/IDO70000_6005a_SLI.pdf

  37. mk January 8, 2013 at 7:26 am #

    “Water that is connected tries to find equilibrium.”

    Physics fail. Water finds equilibrium precisely because it *isn’t* connected, and so the molecules flow freely.

    “this connected water [called the ocean] tries to maintain a level”

    Oceans do not have brains or other control systems and thus are incapable of trying to do things.

    “It does not ever achieve this at any one time but it averages out .”

    This is such a misuse of language as to be worse than meaningless. There is a global average SL but that’s just a mathematical abstraction; a specific locale, with local conditions, is not bound to it.

    “That’s why it’s called sea LEVEL!”

    Uh, no. Consider the noise level in a room or mercury levels in fish. When you try so hard to so obviously misinterpret things in favor of your beliefs, it’s clear that those beliefs override facts and logic.

    “When a point of this sea level is observed continuously over nearly half a century against a fixed object to only decrease [and by a very obvious amount] it is a reasonable to assume that SLs are not rising.”

    No, that’s not a reasonable assumption, especially when there is plenty of evidence otherwise that you simply choose to ignore because it doesn’t fit your beliefs.

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