LATE last year several of my friends sent off postcards as part of the Australian Environment Foundation’s Rivers Need Estuaries Campaign. You can still send a postcard and sign the petition here:
There is a choice of message, for example:
Dear Senator,
Maintaining artificial freshwater lakes using 7.6 kilometres of concrete barrages has:
1. Destroyed the Coorong-Murray River estuary;
2. Diverted water from upstream environments and communities to keep these artificial lakes supplied;
3. Not improved the water security of Adelaide.
I ask you to support moves to:
1. Remove the barrages from the Lower Lakes to restore the Coorong-Murray River estuary; and
2. Relocate Adelaide’s water take-off to a proposed lock downstream from Tailem Bend.
Signed K. Smith
******
Just today there has been a flurry of responses from Simon Birmingham Shadow Parliamentary Secretary for the Murray-Darling Basin to postcards sent last December. The Senator is mostly replying with a form letter as follows:
Dear Ms Smith
Thank you for your email regarding the Lower Lakes.
Firstly, in regards to basin reform, I encourage the Gillard Government to return to the reform process put in place by the previous Coalition Government. Labor has spent only a fraction of the $5.8 billion set aside by the Coalition to invest in efficiency upgrades. A sustainable solution to the Basin requires the Government to get serious about investing in the efficiency of the Basin.
Australians deserve a plan that gets the balance between the environment, communities and jobs right. Before the election Prime Minister Gillard promised to implement whatever the MDBA presented. I hope Minister Burke will take a more pragmatic position and ensures that we get a good plan based on robust evidence – not just any plan.
The Coalition is listening to people across the Basin and is working hard to ensure a sensible outcome is found. An outcome which restores the health of the environment, provides a strong future for regional communities and sustains Australia’s record as a food producing country.
In regards to the Barrages however, I must strongly disagree. There exist very real and very serious environmental consequences if the river does not, with at least some regularity, flush through the Lower Lakes and expel chemical, salinity and sediment build ups (much of which are the result of agricultural run-off) to the sea.
Many people that advocate removing the barrages separating the Lower Lakes and Coorong, which would essentially turn the lakes into a permanent saline state, do not extend the argument about natural state upstream. When Charles Sturt sailed down the river in 1832 there were no locks or weirs and minimal diversion for irrigation.
There were, no doubt, during periods of drought, occasions when the Lakes and Lower Murray did have sea water incursions, however, when drought passed, the volume of water which regularly flowed through the system and into the Lakes pushed salt water back through the mouth. Man’s management of the system and use of water nowadays prevents such regular flushing as nature would have done.
Turning the lakes into a saline ecosystem ignores that they have been largely freshwater, even before the barrages were built, and are of great ecological importance. I encourage you to download the 75 page document entitled ‘A Freshwater history of the Lakes’ available at http://www.gwlap.org.au/docs/A%20Fresh%20History%20of%20the%20Lakes%202004.pdf
If the barrages were removed and lakes were flooded with seawater without significant additional fresh water flows, it is highly likely that they would turn into a dead sea and, during periods where there is little water to flush the salt and sediment through the mouth, the ecosystem may collapse, with salinity and problems spreading up into the main channel.
The recent drought has shone a spotlight on a problem that should have become evident with the closure of the Murray Mouth back in the early 1980’s. Fixing this will require trade-offs – there is no going back to the natural state of the river, but equally maintaining healthy communities along the river requires us to keep it healthy from the mouth up.
It is our responsibility to ensure that we get the balance between the demands of social, economic and environmental needs right. I will certainly be judging the MDBA Basin Plan against all of these criteria.
Once again, thank you for bringing your concerns about the Murray-Darling Basin reform process to my attention.
Yours sincerely
Simon Birmingham
Shadow Parliamentary Secretary for the Murray-Darling Basin
******
Several of my friends have emailed me pleased to receive this response and asked how they might best “engage” the Senator in discussion. Others have indicated to me they are angry that the Senator dared quote ‘A Freshwater history of the Lakes’ by Sim and Muller to them.
I am providing the following information for those wanting to reply to the Senator. And I encourage detailed replies. In fact consider emailing the Senator on this issue even if you haven’t received an email from him – or sent him a postcard. His address is senator.birmingham@aph.gov.au. You might consider copying your reply to your local federal member and also Tony Burke, the federal water minister. His address Tony.Burke.MP@environment.gov.au
Suggested information that could be included in a reply:
Dear Senator
The Lakes Don’t Have a Freshwater History
I am surprised that the best information you can provide in support of keeping the 7.6 kilometres of barrage across the bottom of the Murray River is the report by Sim and Muller ‘A Freshwater history of the lakes’.
This report is essentially a compilation of historical anecdote from early European visitors and settlers suggesting that the lakes contained fresh water. This is not disputed, but the same lakes were often full of brackish water and occasionally seawater. In estuaries water quality is always changing: with the tides, with the seasons and with the climate in the upper catchment. To say that the lakes were predominately fresh and therefore must be always kept fresh is to suggest a steady state when none existed.
Charles Sturt Found Salty Water
You quote Charles Sturt sailing down the river in 1832, it was in fact February 1830, and that this was before locks, weirs and diversions for irrigation. Exactly! And what did Captain Sturt report? He wrote that Lake Alexandrina changed from initially fresh to suddenly salty as he sailed across it and that the Mouth was closed over with sand bars and shoals. Indeed before irrigation the lake was not always fresh and before irrigation the Murray’s Mouth often closed-over. So we should not be concerned by these events and there is no reason to blame them on upstream irrigation.
Without the Barrages the Lake Would Not Become a Salt Marsh or Dead Sea
Like many South Australians you appear concerned that without the barrages, and given current upstream diversions for irrigation that the lake could turn into a salt marsh or at least a dead sea.
There are many very salty lakes in South Australia. But unlike most lakes in South Australia that are dependent on local rainfall, in contrast the Murray is feed from the Snowy Mountains in NSW and Victoria. This provides a regular flush of freshwater each spring.
Lake Alexandrina, even with upstream diversions, still has what is called a “positive hydrodynamics” meaning freshwater inflows are greater than evaporation. In fact freshwater flows into the Lower Lakes are still very significant. So there is no risk that the lakes will become a dead sea.
The Tides of the Southern Ocean Could Flush Out Chemicals and Sediment Build-up
Senator, why would you want to use precious freshwater to flush the lakes and expel chemical, salinity and sediment build-ups when the tides of the Southern Ocean could do the same job with seawater? Back in 1856 South Australian Surveyor General George Woodroffe Goyder suggested that the natural rock bar across the Mundoo channel be removed to improve tidal inflows and outflows along the Mundoo channel and thus improve natural scouring of the Murray’s Mouth.
Why not remove the barrages and let the tides of the Southern Ocean flush the Lower Lakes of chemicals and sediment build-up. This is the natural solution and the solution for every other major river system in Australia.
Yours sincerely
K. Smith
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
“You quote Charles Sturt sailing down the river in 1883”
Jen, he said 1832 in his response above. Of course, 1830 is right.
I watched Lake Durras go super-salty in the early eighties, when those of us who had forgotten about drought were soon to be reminded. I dare say it’s gushing into the ocean now. Its problem is that it’s in a place called Australia. Of course, the Murray is very different, but it is also in a place called Australia, and was breaking hearts long before irrigation. Goyder understood.
I was curious to see that Wiki calls the Myall Lakes “a series of fresh water lakes”. No mention of its special status and RAMSAR recognition. “Fresh” is a very odd way to describe 10,000 hectares of coastal brackish waterways. Is there a spin thing going on here? Are our Green Betters doing some myth building? I’ve caught Wiki at this sort of thing before. Maybe the entry was made by someone without the slightest interest in the Lakes, but it’s very odd.
*****
Robert, correction made, I’ve changed 1833 to 1832 in the reply. Jen
Robert,
Captain Sturt’s first “official” visit to the area was in February, 1830 and he revisited again in 1838 to see if the entrance to the sea he had reahed was the only one that existed. He joined Governor Gawler’s party in1840 and travelled in boats upstream to about present day Morgan.
I know little (translation: zilch, nada, nothing) about the Basin and lakes issue, but on reading that standard response letter this caught my sceptical eye:
“There exist very real and very serious environmental consequences if the river does not, with at least some regularity, flush through the Lower Lakes and expel chemical, salinity and sediment build ups (much of which are the result of agricultural run-off) to the sea.”
Surely the tides would do an equally good job? If salinity “builds up”, that shows that even with the barrages in place, sea water intrudes. Without the barrages, more sea water would enter, and tidal ebb and flow would flush out “agricultural run-off”.
If as he says “Turning the lakes into a saline ecosystem ignores that they have been largely freshwater, even before the barrages were built”, then why were they built? All large rivers just upstream of their estuaries have regular saline flushes (sounds vaguely like a gynaecological disorder) and are none the worse for it; the tidal ecosystems are just different. “Largely freshwater” admits that they were partly saline. It sounds as though there’s a need to justify the great expense and negative environmental impact of building the barrages in the first place.
“If the barrages were removed and lakes were flooded with seawater without significant additional fresh water flows, it is highly likely that they would turn into a dead sea” – what a load of crap! Saltwater lakes are biologically diverse, with far more species than freshwater, IMHO – they’re just different. Note his cunning use of “fresh water” which though technically correct, actually means laden with his “agricultural run-off”. He clearly has no evidence for that claim; if he had he would have cited it.
Am I on the right track, Jennifer, or just exhibiting total ignorance of the issues? There’s more to this political (it’s plain it’s not truly environmental) issue than meets the eye, or at least MY eye.
I received the same reply. I downloaded the recommended “history” (the Senator’s Freudian slip in calling it A Freshwater History — it’s real title is A Fresh History — was actually spot on; it’s very selective) and was immediately struck by the omission of Sturt’s discovery that the lake was not all fresh water. Further into it are some photos from another book showing very low water in the Goulburn and Murray rivers said to have been caused by upstream extraction.
But the caption says they were taken in the early 1900s. Wouldn’t it be more likely that the low levels were caused by the Federation drought? Does anyone have this book, Nile of Australia by David Gordon? It was written in 1906 apparently so “early 1900s” would be about right for one of our worst droughts. I wonder if the captions in the Gordon book tell us more than this “Fresh History”. The first Goulburn photo looks to me like it was taken well upstream of what is now Eildon weir and would therefore not have had much if any water extracted.
I will be bringing this to the good Senator’s attention.
Great you are going to reply to him, David.
Spot on, Tony.
Sean and Robert, take 10 minutes out of your day to email the senator about Sturt if only to cut and paste the following:
Dear Senator Birmingham, You quote Charles Sturt sailing down the river in 1882, it was in fact February 1830, and that this was before locks, weirs and diversions for irrigation. Exactly! And what did Captain Sturt report? He wrote that Lake Alexandrina changed from initially fresh to suddenly salty as he sailed across it and that the Mouth was closed over with sand bars and shoals. Indeed before irrigation the lake was not always fresh and before irrigation the Murray’s Mouth often closed-over. So we should not be concerned by these events and there is no reason to blame them on upstream irrigation.
For some perspective: the Myall Lakes are home to as many bird species as Kakadu. They are one of the largest brackish systems in the southern hemisphere (bit of a factoid, I know), and they’re part of a busy National Park easily reached from Newcastle and Sydney, with plenty of development on the fringes. (I’m enough of a tree-hugger to wish away water-skiers, generators and, especially, cars on beaches, but I love the fact that huge numbers can pour into these special places and they hold up just fine. So I keep my elite wishes to myself.)
Just in case anyone thinks “brackish” is a bad word.
Robert, The Myall lakes include the lakes near Forster right? With all the oyster beds? You don’t grow oysters in freshwater. Why don’t you make yourself an editor at Wikipedia and correct the listing? And while you are there you could correct some of the information relating to the Lower Lakes?
Hi All
Extracts I made from
The Senators Bible.
A Fresh History of the Lakes : Wellington to the Murray Mouth, 1800s to 1935
handed out by the E&H Department at the last two meetings in Goolwa shows howthings have not changed.
The below is from the Summary of Events from the book
1885 New South Wales and Victoria sign an agreement dividing waters of Murray.
1886 Premier of Victoria writes to Premier of South Australia suggesting that S.A. set up a Royal Commission of enquiry into the River Murray.
1887 Debate in the S.A. Parliament regarding the River Murray “ Many people imagined that there would be nothing to fear form only flood waters being taken, but this was a great mistake. All the floodwaters were required to drive out the salt water. There was a fear that extraction of water for irrigation would cause the Lower Murray to become impregnated with salt to a considerable distance above Wellington.
1888 Point McLeay Aboriginal Mission requested a grant of 500 pound to set up an irrigation scheme to enable root crops to be grown. Mr Taplin explained that they wanted equipment to pump 30,000 gallons per hour from the lake after raising it thirty feet. He said “ the water in the lake was eminently suited for the purposes.
1889 A report by Mr. Russell, the government astronomer from N.S.W., that the rainfall in the basin of the River Darling in 1879 only 2.32 % reached the sea. In 1885 the proportion was only 0.13%, and of the rainfall in the catchment area of the Murray only about 25% reached the sea.
1901 Because of low river seawater is coming into river at Goolwa.
1902 5th June Southern Argus. The Murray Waters Commission when taking evidence regarding changes to Lakes Alexandrina and Albert visited the Angas family Point Sturt property. The manager Mr Nicholls informed them that he “had been aquainted with Point Sturt for 12 years , and noticed a great change in the waters of the lakes. The first serious trouble occurred six years ago, when he lost a number of valuable stock. He thought the drought was the cause of the saltiness of the lakes. 24th July The Southern Argus. The Milang fishermen were catching large quantities of mullet and very few cod because of the brackish conditions found in the lake. Plus there are many reports through to 1905. Bores and wells needed to be sunk, around the Lakes, to provide water.
1904 Mr Pearce of Point Sturt said that the reeds were dying and swamps were becoming useless for running stock on them because they were becoming impregnated with salt. South Australia was under the impression that Victoria was extracting 75% of water in the Upper Murray. Nothing mentioned re N.S.W.
1912 The Southern Argus said that nothing done to protect the lakes despite it being talked about since that newspaper began in the 1860’s.
1915 Saltwater in the River at Mannum. Willows at Wellington found to be dying as a result of salt water being there last year.
Section 3 European settlement caused change:
The period 1915 to 1940 their are numerous incidents of salt water and sea water entering the Lakes to Goolwa e.g.
1920 The Southern Argus carried a report on a meeting held at Strathalbyn where the Director of Irrigation, Mr McIntosh, “ touched on the possibility of the lakes becoming salt when the extensive withdrawals of water for the upper river irrigation works were made on the supply coming downstream, but hoped that some suitable storage scheme might be devised to compensate for the loss, and for the quantity taken from the lakes by evaporation.
1930 29th May The River Murray Commission met at Milang, Mr Eaton (a member of the commission) pointed out that it was hopeless to expect much freshwater downstream to freshen the lake, as it would require a million acre feet to do this, and the total average flow was only four million acre feet. The other states refuse to allow for the evaporation regarding the big surface area as useless and wasteful. The other states refused to listen to South Australia on this matter; and possession being nine points of the law they had their way.
DRAIN LAKES
1905 / 1906 drain Lake Albert and reclaim the land.
1923 / 1924 suggestions made that both Lake Albert and Alexandrina be drained.
1929 Residents around Lake Albert condemn the proposal of draining it.
I will forward part two shortly.
I left the header off Part One :-
Part Two “IT ALL GOES BACK TO 1885”
Artificial Fresh Lakes : Wellington to the Murray Mouth, 1940 to 2009
The Drought Update for June shows that Murray-Darling Basin has had the 9th consecutive autumn with below average rainfall. Murray system inflows for May were only 90 GL which is slightly above the record low of 75 GL (in 1902) but well below the long term average of 390 GL.
For the 2008-09 water year (June 2008 to May 2009) Murray system inflows were the 3rd driest in 118 years of records. This follows the 7th driest year in 2007-2008 and the driest on record in 2006-07. Murray system inflows have been below average for nine out of the last ten years.
January – May 280GL Historic Minimum (Previously 295 GL 2007)L/term Av 1,200 GL
3 year total 5,040 GL Hist. Min.(Previously 11,180 GL (1943-1946)L/term Av 26,700GL
MDBA report 10th June, 2009:- Dartmouth 831GL (21%), Hume 229GL (8.0%), Lake Victoria 175GL (26%) and Menindee Lakes 221GL (13%) stays in NSW government control below 480GL and back to the MDBA when it reaches 640GL. The Murray Darling Basin storage is 9,352 GL and currently is holding 1,456 GL which is a deficit of 7,896 GL. The Sunday Mail shows photos of Lake Mulwala the storage pond for the largest irrigation system in the southern hemisphere being reduced to the original river channel. The backwaters in S.A. from Blanchetown to Wellington are in a similar position you only have to refer to MDBA website to see the photo of the River Murray near Murtho.
The article in the Weekly Times on a new satellite study on the Murray Darling Basin has found that 400 Sydney Harbour’s in volume of water has been lost in the last six years.
A survey I have done on the rainfall in the basin shows that the three years leading up to the 1956 floods the total rainfall was 19512.4 mm ( av. 6504.1) with 1956 being 8002.1. In the same area 1999 to 2008, 42782.5 mm (av. 4278.3) the highest recorded was 5883.4 mm in 2000. The mean average for the area 4910.1 mm and the highest is 9322.8mm.
With all the above information I cannot see how enough rain and water buybacks is going to correct the matter for quite sometime.
In S.A. it had taken from 1885 until 1938 to turn the Lakes into a salt and seawater cocktail. In 1940 the artificial Lakes were created by building the Barrages and in the meantime a RAMSA agreement has been signed. The River Murray Barrages Environmental flows study for the Murray – Darling Commission in June 2000 appears to have fallen flat as dredging began at the Murray Mouth 2002. January 2009 the Environment and Heitage Department came to Goolwa to tell us that Lakes were again in trouble. This time it much worst Lake Alexandrina reached a record low of -1.4 m AHD in April 2009 and currently the salinity level at Milang is 5,800 EC, Lake Albert 10,500 EC and the Goolwa 27,000 EC The Finniss River, Curency Creek and Goolwa Channel have acidity problems and have been treated with aerial spraying with limestone and Rhye grass.
Construction of the new pipelines with filtered water from Tailem Bend to properties in the Lakes district and Langhorne Creek connected to the Strathalbyn supplied from Murray Bridge. The irrigators will have their separate pipeline via Jervois, Langhorne Creek and Currency Creek completed by October, 2009, the reliance on the Lower Lakes for water being transferred upstream to Tailem Bend.
Mr. Holmes main concern is to manage the health of the Lakes the weir relates entirely to Adelaide’s water supply. It isn’t a device to manage the Lakes,” he said. If that is the case why hasn’t he objected to or stopped the above pipelines as he has to sea water. Two of his fellow government departments Water Security and Agriculture Food and Fisheries have increased the problems for the Lakes as more water will now be extracted from the River before it reaches Wellington.
The various Government Departments do not want to be the first to bight the bullet and allow seawater in. Water Security cannot say yes at this time as it interferes with the Tailem Bend and Murray Bridge pumping stations without building the Lock between Tailem Bend and Wellington. The Environment and Heritage will not make a decision and leave as is and praying for rain. The RAMSAR agreement surely it just as good in a seawater environment as it was in the 1940 artificial created fresh water Lakes, after all the Coorong is seawater. Governments have had two tries between 1885 until 2009 (124 years) and still haven’t been successful.
The big surprise could come from the Commonwealth Government after burning the “MIDNIGHT OIL” a man called Peter may realize that by managing the system as an estuary would restore a diverse and productive system.
Build Option C and F Estimated now $26,000,000.
To be sea water reduces the cost, eliminates pumping of fresh water and eliminates noise pollution of the pumps.
Allows the full Goolwa Channel to be available from Clayton through the barrage to Murray Mouth and Coorong eliminating buses and some trailers to the Mundoo Channel. Spirit of Coorong can come back to the wharf along with other operators.
The only slight hiccup will be, The Oscar W will have to carry extra fresh water on board for it’s cruises.
The Wellington weir still no starting date, which will take six months to build, now looking at a November 2009 finish. We are spending a lot of money ( $400,000,000 + ) a temporary weir is not good enough it must be a permanent barrage with regulatory gates and a lock. The lock gives the river that continual boating activity that has happened in the past eg. The Source to the Sea and boat numbers will increase for The Wooden Boat Festival. Finally let the sea water in when it is complete, it will be a long time before we get the rain and water ( if we do ) at least it will be sea water that will be evaporating at the rate of 1,102 GL/ year which is only 420 GL less than what is currently stored in the Basins.
Jen, Myall Lakes constitute the system to the south of Wallis Lake and Forster, where many oysters come from. The Myall River, where it’s salt toward Port Stephens, is also famous for oysters and fish. Interestingly, between the two systems is Smiths Lake, which tends to be fresh though it’s artificially drained to the ocean when it gets too full. Surprisingly hard to find info on present salinity, conditions etc.
Myall Lakes are unique in being vast and brackish, though I don’t know what this 50s style “climate change” has been doing to them lately. The famous Myall Lake prawns sell for a premium. I’ve long assumed that the brackish has something to do with this.
30 years ago, I spent an extraordinary Christmas hols doing a “bush wade” around the drought stricken brackish lakes, an adventure which would not have been easy in the decades before. My visits since then have been rare and brief, but, if I can get down there for a time, I’ll pluck up the nerve to do some editing. (I have vague dreams of spending some of my sixties exploring the waterways between Port Macquarie and Port Stephens in one of these great new touring kayaks that have become the rage with fishermen.)
The main point is, brackish can be very, very good.
When younger used to go camping at Smiths Lake. Had a little boat in which I sailed and did some fishing. Used to catch prawns at night with net and torches. Enough prawn to eat and use as bait (in the lake and from the rocks at the ocean). The lake opened to the sea a couple of times a year. Fish- mullet, flathead, whiting and catfish. No commercial fishing then. Understand there are some commercial fisherman in the lake now but going tough because too many people now (locals and holiday visitors) have depleted stock.
Jen, since you appear pleased I am replying, I have sent this to the senator:
Dear Senator,
Thank you for your reply to a postcard which I thought was going to The Hon Tony Burke but which seems to have got into many other inboxes.
I must say your reply was far more reasoned than those from either Minister Burke or several Greens and Labor senators.
As you suggested, I downloaded and read A Fresh History. I’m sorry to say this to a coalition senator but it did not change my mind by one iota.
I found it very selective, beginning with the quote from Sturt commenting on his discovery of Lake Alexandrina. Further into his account (of which I have had a copy for some years), Sturt tells of encountering salt water as he crossed the lake, forcing him to return to where his party could replenish their drinking water supplies.
I am surprised that a book purporting to be a history could omit such a relevant fact.
Some of the photos used are a worry too. One, of the Goulburn river, claimed by the caption to show the effects of water extraction appears from the narrowness of the stream banks to have been taken on the upper Goulburn, well upstream from any irrigation scheme of significance in the early 1900s.
Others show the Murray, similarly affected.
The early 1900s as I’m sure you know were at the height of the Federation drought, one of the worst recorded in Australian history. Since the book, Nile of Australia, given as the source of the images was published in 1906, I would suggest that it was the drought which caused the rivers to run almost dry as depicted.
Last night I spent a couple of hours on the National Library’s Trove newspaper website and retrieved a number of newspaper clippings from as early as 1833 (Sydney Morning Herald) suggesting that the lake was brackish or salty on numerous occasions, long before any large scale irrigation.
Regarding the early 1900s, I think the following comment from an experienced river boat owner sums it up pretty well:
“The river,” says Mr. Lanseer, “has not been navigable for some time and, like its tributaries, is almost dry at the head. The reason is the drought, and not that water is being drawn off for irrigation purposes. If there were a general fall of rain of from 1½ to 3 in. the river would soon become navigable and remain so for a considerable period. (The Advertiser, Adelaide, 19 August 1902)
Since I have taken your advice and read A Fresh History, will you please read the report by Dr Jennifer Marohasy at this link? http://jennifermarohasy.com/wp-content/uploads/2012/02/Plugging-the-Murray-Rivers-Mouth-120212.pdf
I think you will find it covers the history of the lake in a far more comprehensive and reliable manner than the one you recommended.
Best wishes
David Joss
Interesting that he is replying to an email that was not directed to him AND that he is shadow secretary for the MDB.
Disconcerting actually when you consider what he has to say. Wonder if his fearless leader knows what he is up to.
And I wonder just how far the list of email addresses I am now on has circulated. And why…
David
Excellent reply. 🙂
I’m thinking that the email went to your local member and he/she must have on-forwarded it to Senator Birmingham because he has responsibility for this issue for the Coalition? Do you have a coalition local federal member?
I wonder how many are aware that the Myall lakes & river were part of the overland route from Sydney to Brisbane.
The coach went to Port Stephens, transship the passengers to a boat, which went up the river & lakes to the top end. A short cart ride then crossed the mile or so of land dividing the Myall from Wallis lake, then boat again to Tuncurry, opposite Foster, where they boarded another coach.
If Oz had been settled a hundred or so years earlier, we might have a man made inland waterway from Sydney to Brisbane.
Need I remind you guys the places like the Myall Lakes remain through the efforts of those hard headed pioneering advocates, Myles and Milo Dunphy. Thus began the true history of Australian environmentalism
Gavin, National Park, now the Royal National Park, was established with breathtaking foresight in 1879. Interestingly, the great John Robertson, the acting premier responsible for its establishment, died in 1891, the year Myles Dunphy was born.
David Joss:
Pesky explorers and newspaper archives, ruining what would otherwise be a comprehensive rewriting of the past for the benefit of present and future generations of dumb proles. This has been going on since well before M. Mann esq. produced (or was it conjured?) his “iconic” (his word) hockey-stick chart eliminating the well-attested MWP while leaving the LIA intact (not surprising as the latter serves to increase the slope of “anthropogenic global weirding”). Why let facts spoil a perfectly good story?
I apologise for mentioning Michael “3 lonesome pines” Mann so often, but he’s my particular bête noire at the moment. It’s not that I don’t have heroes, just that I need to practice throwing darts.
gav
You were saying?
Both major parties are tarred with the same brush.
Until we have a truely rural based, regional australian voter block we are widdling into a northerly.
For the record, Sturt’s trip to the area was in February of 1830 which is the beginning of the Murray’s low flow phase. More importantly, it was also the end of what was, at the time, referred to as “the great drought” which lasted 3 and a half years from 1826 to mid 1830. The only similar events in the recrds from 1900 to present are 1900 to 1903, 1940 to 1944, and 2006 to 2008.
So Sturt recorded conditions at the end of a 1 in 50 year event which also included an extended period of zero flow. Not surprisingly, the mouth was closed and sea water intruded half way into Lale Alexandrina. So it is highly misleading for Jennifer to continue implying that mouth closure is some sort of normal feature that one might observe on a sub-decadal, or even decadal basis.
And it is even more misleading to suggest that barrage removal would “restore” conditions in the lower lakes if it does not include every last drop of up-stream irrigation water during the other 47 years of this particular flow cycle.
Apart from a single, part year, no-flow event in 1839, the closure of 1830 was balanced by a sequence of average and above average flows over at least the following two decades, if not five. That sort of sequence cannot be replicated in future unless the irrigation allocations are very seriously reduced as well. And to pretend that the barrage removal half of a “restoration” would not produce conditions leading to even more strident demands for the irrigation half of the equation is worse than naieve, it betrays a callous disregard for the consequences of one’s actions.
Read how Jennifer’s calculation of a million megalitres of annual fresh water evaporation savings completely evaporates under proper scrutiny at http://regionalstates.wordpress.com/2012/04/17/barrages_and_murray_mouth_mirages/
Ian,
Wouldn’t it evaporate a million fewer megalitres of fresh water from the lakes if a few million less megalitres of fresh water entered in the first place ?
No, Dave, read the article.
Ian,
How do you read a not found article on the above address ?
Thanks Sean, try http://regionalstates.wordpress.com/2012/04/17/barrages-and-murray-mouth-mirages/
Ian Mott:
Reading both of your posts “So much Murray River flow and so little to show for it.” and “Barrages and Murray Mouth Mirages” I can see some possible logic disconnects and omissions. I don’t know enough of the geography to crystallise or dispel my impressions, but will research and ponder. You certainly provide a lot of data to absorb and analyse.
Ian,
That’s better.
Peter,
Where have you disappeared to, haven’t seen or heard from you since your T.V. and The Advertiser appearances ?
How is Lock Zero going ?
A different friend of mine who also happens to be named Ian, sent me this link below for a history of droughts and weather patterns across the MDB that are much clearer than Mr. Mott and his fancifull shock and awe maths.
http://home.iprimus.com.au/foo7/droughthistory.html
Susan
Your history of drought link is interesting. But I’m sceptical about drought drying up the Murrumbidgee in 1830 etcetera.
A primary source must be Sturt’s diary and he travelled down and then up the Murrumbidgee in that same year. Interestingly early in the year he describes the Murrumbidgee as flowing strongly and their whale boat as being jettisoned from the Murrumbidgee into the Murray by the current.
I will need to go back and re-read how it was on his return later in the year, but I’m remembering there was water in the river and more.
The Darling was also flowing strongly early in the year and mention is made of very significant inflows from the Rufus River a bit further downstream.
But of course its not drought that will open or close the Murray’s Mouth, coastal processes dominant except during flood conditions.
There was flood about 8 years later.
Really, Tony Price? The correct term for “possible logic disconnects and omissions” would have to be “wishful thinking laced with conceit” would it not? When you actually have something to talk about then by all means mention it. Until then you might consider going to the far queue.
Susan, if you had bothered to read ALL of that link you might have realised that I have used the same source. And kindly have the intellectual integrity to make specific mention of any aspects of my “shock and awe maths” that you regard as “fancifull”.
Is evaporation from the lakes lowest in Autumn/Winter or not?
Is rainfall highest during that interval as well?
Does median rainfall exceed evaporation in 3 of the 6 lowest flow months or not?
Does local runnoff also negate evaporation in this period or not?
And I note that Jennifer has avoided the key issues again. She accepted (over at the Just Grounds discussion) that there can be no evaporation deficit (decline in water volume) while the river is flowing but then claimed that a deficit would occur during low flow periods. But if the Spring/Summer evaporation deficit is negated by river flows in 9 out of 10 years, and the much smaller Autumn/Winter evaporation deficit is negated by local rainfall and runoff, even in first decile events, then there is no significant deficit for sea water to replace in 9 out of 10 years.
It is only at the end of extended 1 in 30 to 50 year events with two or more years of zero flow and first decile local rainfall that the cumulative net evaporation deficit would exceed half the lake volume. And when this extremely rare, and temporary deficit is averaged over the entire interval then the claimed one million megalitres of claimed “saved” fresh water evaporation is revealed to be at least a 100 fold exaggeration.
That does not constitute a mere ‘margin of error’, it is a gross misrepresentation of fact that has no place in any formal policy process.
Ian
I really don’t think we are arguing about the same things when it comes to evaporation and what keeps the Murray’s Mouth open.
My calculations and rational are here: http://www.mythandthemurray.org/calculating-evaporation-from-the-lower-lakes/
Which bits did I get wrong?
Ian Mott April 27th, 2012 at 10:24 am
“Really, Tony Price? The correct term for “possible logic disconnects and omissions” would have to be “wishful thinking laced with conceit” would it not? When you actually have something to talk about then by all means mention it. Until then you might consider going to the far queue.”
You’re an insulting bugger, aren’t you? I said “I don’t know enough of the geography to crystallise or DISPEL my impressions”. I was trying to give your massive missives a fair crack of the whip. Gloves off then?
Ian,
Prof. Tim Flannery is quoted in an article “The Australian” 12th. July,2008 “Heroic Action” sought for lakes.
The Lower Lakes has an evaporation rate of 1300 Gl a year.
Calculations I have worked on :-
Evaporation Loss (EL) @ 1.3 m/a
Lake Albert 185 sq.KM 240 Gl/a
Alexandrina (upper zone) 523 sq. KM 680 Gl/a
Alexandrina (lower zone) 100 sq. KM 130 Gl/a
Goolwa 40 sq. KM 52 Gl/a
TOTAL :- 848 SQ. KM 1,102 Gl/a
You went wrong, Jennifer, by using the gross figure, not the net, after deducting rainfall. The sum of the BoM’s mean monthly pan evaporation figures is 1565mm to which I applied a more conservative 80% multiple to get an actual gross of 1252mm. As mentiones in my article, other MDBA sanctioned research has used multiples up to 95%. If you want me to use your more adventurous 75% multiple I will be happy to oblige but it will produce an even lower volume.
Mean annual rainfall should then be deducted from the actual evaporation figure to give the net loss. At Meningie Mean Annual Rainfall is 468mm which, when deducted from 1252mm leaves a net evaporation figure of only 784mm. And this, when applied to the 75,350ha area of the lakes when they are at the AHD level that would be the case if the barrages are removed, means a volume of only 590,000ML.
You do accept, I hope, that rain that falls on a lake is also the first to be evaporated again. So leaving it out of a calculation of evaporation savings is not only very poor science, it is highly misleading. And if you had actually retained anything from my article you would have known this before you posted your link to your misleading, unprofessional McFactoid.
Sean is obviously using the surface area when the lakes are at AHD+75cm, which would not apply if the barrages are removed. And frankly, anyone who would seriously quote Flannery as an authority on anything has trashed their own credibility. The clown is so full of spin he is effectively innumerate.
OK Ian. My range is based on gross evaporation and doesn’t include local rainfall.
I detailed all of this, and don’t think anyone else would have expected me to have included rainfall or inflows. What methodology does includes local rainfall?
Evaporation and rainfall are two different things?
To cut and paste from my little article:
“These published studies which take into account meteorological variable and lake characteristics are in reasonable agreement and give an annual volume evaporated of between 878 and 1083 GL.
“The higher evaporation volumes, including the often quoted figure of 1,300 GL, may be based on the simple multiplication of annual evaporation rates for the Lower Lakes area [8] by the surface area of the lakes divided by 1,000, for example (750 *1750)/1,000 = 1,312.
“A scientist familiar with the technical literature would insist this figure be multiplied by the relevant coefficient for natural water bodies (0.75) and this would reduce the volume evaporated to 984 GL. This figure is again in general agreement with output from the published peer reviewed studies.”
So what is your figure Ian?
Ian said:
“You do accept, I hope, that rain that falls on a lake is also the first to be evaporated again. So leaving it out of a calculation of evaporation savings is not only very poor science, it is highly misleading. And if you had actually retained anything from my article you would have known this before you posted your link to your misleading, unprofessional McFactoid.”
If I’m calculating possible savings on outgoings from my bank account is it “misleading, unprofessional” not to include income? Is the recently deposited income the first to be spent? Your thin argument is developing logical holes also.
Full marks to Jennifer for maintaining her cool, whether she’s right or not. I can take reasoned criticism, I can be proved wrong, and if I am I accept that and move on, enlightened, educated, if somewhat chastened and occasionally embarrassed. Jennifer appears to me to be similar in that. I said earlier you’re an insulting bludger (too lazy to think outside your envelope), and you display the arrogance of your ilk who respond to criticism by bluster and insult. You refuse to even contemplate that any one of your unsubstantiated claims, opinions and calculations are even slightly wrong. You need to take a deep breath and count to 10 mate.
Hi Tony
I like your bank account analogy.
And so there are many ways that water can be added to a lake and also lost from a lake. Water can be added by inflows from rivers, inflows from the sea, inflows from groundwater, and also from rainfall. Water can be lost by flowing out and also by evaporation.
Undertaking a net water balance is very different proposition from just calculating evaporation. I was just calculating evaporation using simple and accepted methodology.
I think it useful to have a ballpark evaporation figure to place in the context of Murray river inflows. This Murray River inflow value last time I looked was a much, much more significant input than either local rainfall or local inflows (ie from Currency, Langhorne or any of the other local creeks).
Cheers,
PS At some point in the last couple of years Ian decided I was the enemy and now spends much time attacking my work (and he is not the only one wagging a campaign against me). I did attempt to engage in a meaningful way for sometime with Ian and then I realized he often was just creating strawman arguments by misquoting me and then shooting down what I hadn’t ever said/written. But keeping up with this, for e.g. at blogs, takes more time than I am prepared to waste on the same, though it is potentially much more damaging to my reputation to leave things unchallenged.
Jennifer:
“PS At some point in the last couple of years Ian decided I was the enemy and now spends much time attacking my work (and he is not the only one wagging a campaign against me).”
He’s wagging something, not sure what it is. I said I’d give his massive missives a fair go, and I’m doing just that right now. He says:
“At no stage does the AEF appear to have made any attempt to quantify the likely volume of tidal intrusion based on the atypical (to the point of yet more SA weirdness) tidal behavior in that location. There is generally only one tide each day, and that is only during the 50% of the lunar cycle when they even take place at all. And, aside from storm surges, they only exhibit a tidal range greater than 70cm on 4 or 5 days each month.”
My special interest is in sea level, and because the BOM/National Tidal Centre supply much up-to-date high-quality data on Oz and Pacific gauges, my focus has been on these. The nearest gauge to the Murray mouth is at Victor Harbor to the west, and the BOM provides both historical aggregated data and tide predictions for that location. Kingston rather further to the SE shows a very similar pattern so it’s not unreasonable to conclude that tides at the mouth are similar (unless there’s a gravity hole there). Indeed there’s quite likely to be a small positive “focussing effect” due to the shape of the coast just there. Even a casual perusal of BOM data shows that Ian’s “only one tide each day” and statistics are bogus.
Predictions:
http://www.bom.gov.au/oceanography/tides/MAPS/sa.shtml
Historical:
http://www.bom.gov.au/ntc/IDO70000/IDO70000_61490_SLI.png
Still digging.
I see tidal analysis as rather important in this discussion. Either side of the SA/VIC border, the tides do indeed show an unusual cycle, one I’ve not seen before. For about half the lunar month, there’s an average of one tide a calendar day (the lunar “day” is 25 hours because of its rotation around the Earth). During the other half there are two, with increasing tidal range for the second tide, decreasing as the “single tide” cycle is reached. The tidal range is around 70cm as Ian said, BUT that’s an average imposed on monthly and annual cycles, which means that “high water” can be as much as 90cm above average annual MSL (mean sea level), with the highest in May and early June.
Ian’s statement on tides is clearly incorrect:
“There is generally only one tide each day, and that is only during the 50% of the lunar cycle when they even take place at all. And, aside from storm surges, they only exhibit a tidal range greater than 70cm on 4 or 5 days each month.”
In summary, there is one tide each day for half the lunar month, two during the other half, with similar tidal range. That covers the whole month, not just 50%. There’s a tidal range of 70cm or greater for about half the month in two weekly periods, not “4 or 5 days”. High water varies from roughly equal to monthly MSL (during the low part of the monthly cycle) to about 70cm ABOVE MSL, the latter over a few days. The extreme tidal range over the month is about 135cm, over the year it’s as much as 160cm. I’ll post a chart on Picasa Web for Jan/Feb 2012 to illustrate this.
Now you are just reverting to pure casuistry, Jennifer. The whole point of double entry bookkeeping is to show a net result. To show only one side of the ledger is a failure to present a true and fair view. By only mentioning the evaporation portion you clearly imply that this is the total volume that is sourced from murray river flows and available to be saved by your imaginary solutions. The inescapable fact is that 468mm of your adjusted evaporation has not come from the river at all, it is water that fell on the surface of the lake. And it will continue to fall on the lake if it was full of sea water.
Tony Price’s links demonstrate that he has no idea what he is looking at.
Go to http://tides.willyweather.com.au/sa/fleurieu-peninsula/goolwa-beach.html and look at the graphs below the tables. At the graphs go to the calender and go to 13/04/12 and right click the arrow forward for the next few frames and observe the changing patterns. Then go back to the calender and go to 18/10/2011 and right click through to 5/11/2011 and observe the same sort of patterns I referred to. That is, an asymetrical pattern with steep inflow phase and gentler sloped outflow, with high amplitude for each second week that degrades to little more than 20cm tidal range in the alternate weeks. AND IN MOST CASES, ONLY A SINGLE HIGH AND LOW EACH DAY WITH A BARELY PRESENT FLUCTUATION BETWEEN THEM.
If Tony was capable of interpreting a table he would know that the BoM tables also display a similar change in pattern for Victor Harbour.
So where does that leave us? Jennifer defending a highly misleading omission and Price talking through his backside.
And what about the fact of the river flows, Jennifer. Do you still accept that there is minimal scope for substituting sea water for fresh while ever there are river flows to replace evaporation losses? Or are you now denying gravity?
And are you still claiming that there will be significant scope for substitution during the winter low-flow periods? Are you now pretending that winter rainfall doesn’t match and often exceed winter evaporation?
And are you still pretending that it doesn’t take more than a year of zero flow for the fresh water derived portion of the lakes evaporation to account for even 50% of the total?
And spare us the “hes got it in for me” crap, Jennifer. It might work with you little band of sycophants but the record is absolutely clear that ALL of my criticism has been directed at the evidence and your penchant for ignoring what you don’t want to consider. Don’t you feel just a little bit embarrased that a goose like Flannery thinks your ideas make sense?
Hi all,
This is a very interesting thread begun by some extremely doubtful threads.
The Barrages did not: –
“Destroyed the Coorong-Murray River estuary” as the seawater history was only about 20% of recorded history, so that sentimental bull***t!
“Diverted water from upstream environments and communities to keep these artificial lakes supplied” also bulls***t as Lake Mulwala was part of the trade-off for the Barrages and not the 26 locks that were first proposed!
Why would Adelaide’s take-off’s need relocating, “Relocate Adelaide’s water take-off to a proposed lock downstream from Tailem Bend” as Adelaide’s off takes need to be moved from Murray Bridge 112-Kilometres and Mannum 150-Kilometres by River from the Barrages
Hi Tony Price,
Re, “Surely the tides would do an equally good job?” no they would not as the incoming tide would deposit more sand than the outgoing tide would shift.
Hi Sean,
Why would anyone take any notice of Flannery?
To all,
When calculating evaporation from Lakes Alexandrina and Albert after you arrive at a figure you must then deduct rainfall, inflow from Currency Creek, the Bremar River and groundwater inflow.
Hi Jeniffer,
Re, “But of course it’s not drought that will open or close the Murray’s Mouth, coastal processes dominant except during flood conditions” more uneducated comment if the River’s flow will not keep the River Murray’s mouth open the tides WILL close it!
Hi Ian,
It is disappointing that so many people just believe what they want to believe and not seek the truth, thanks.
Ian,
I wasn’t calculating net water balance: if I was I would have included inflows from the Murray River.
There is a methodology for estimating evaporation from a water body, I applied that methodology.
You appear to just make it up.
And I’m still unclear what your figure is for evaporation from the Lower Lakes?
Go back to my post above, Jennifer, at 3.00pm on April 27. Your attempts at avoiding the fact that you left out local rainfall in your claims of evaporation savings fool no-one but your little rent-a-crowd. By only using the gross figure x multiple you imply that this is the amount of the saving when 468/1252mm (37%) was never in the race to begin with.
So lets spell it out again for the plodders, shall we? The first water to evaporate today will be the rain that fell on the lake last night. That will be the case whether the lake has sea water or fresh water so it was entirely false and misleading of you to fail to mention this highly relevant fact. If you made such an omission in a prospectus you would cop a stretch in prison.
And still no response to the more damning parts of your incredibly shrinking evaporation savings.
If the river is still flowing then any loss of lake volume through evaporation will be replaced by more fresh water. Tides will simply come in and go back out as they always do.
If the tides do manage to intermix with fresh water after barrage removal then it is obvious that some of the fresh water will have gone out with the ebb tide to compensate. In which case, why is that not regarded as just as big a waste as evaporation?
Why did you claim that sea water would be able to replace evaporated fresh water during periods of low flow when the reality is that evaporation is so low, and rainfall is higher which, when combined with local run-off, exceeds evaporation during those low flow months?
You actually flatter yourself, Jennifer, when you claim that I regard you as an enemy. I have no use for such indulgences. But bull$#it masquerading as science, and ignorance laced with a selective approach to the facts has always been, and should remain, the enemy of all of us.
Hi, Peter, welcome to another session of honest toil in the bimbosphere.
Ian,
Can you just tell me/us exactly what your figure is for evaporation each year from the Lower Lakes… approximately?
How much water is evaporated from the Lower Lakes in an average year?
Jen
Peter,
It must be still Easter.
You are alive, thank god for that.
I like to take this opportunity to thank you on your recent efforts both in the press ( The Advertiser ) and on T.V. ( via my Computer ) as spokesperson in the manner you put forward the argument for LOCK ZERO.
Hi Sean,
Why would anyone take any notice of Flannery?
Professor Tim Flannery has a title just like yourself. As you can see ( 1,102Gl/a) I did not agree with his figure.
To all,
When calculating evaporation from Lakes Alexandrina and Albert after you arrive at a figure you must then deduct rainfall, inflow from Currency Creek, the Bremar River and groundwater inflow.
How much have they contributed to the Lakes from 2002 through to 2009 ?
The only one that did contribute in these years you left off the list FINNISS RIVER.
Ian,
“who would seriously quote Flannery as an authority on anything has trashed their own credibility”.
That is why I quoted my figures and not his.
“Sean is obviously using the surface area when the lakes are at AHD+75cm, which would not apply if the barrages are removed”.
When have I said the Barrages were to be removed.
Secondly it is good to see the Lake Albert farmers are now looking to turn it into a transit lake.
Lock Zero & Automation of Barrages
1. Lock Zero
Build Lock Zero below Tailem Bend this creates a new pool of 0.75 M between Lock Zero and D/S Lock 1 and protects Adelaide’s water supplies and the Tailem Bend, Murray Bridge, Mannum and Swan Reach pumping stations. It will eliminate the damage the Lower River Murray suffered during the drought. The Lower Lakes pool can then be lowered to 0.50 M AHD (now 0.75 M AHD) save 694 GL.
2. Re-Engineering the barrage gates
The Goolwa Barrage gates to be an automated system and with proper management will be able to control the water levels of Lakes Alexandrina and Albert. The pool level could be increased to 0.75 M AHD open the gates at low tide and flush the Goolwa channel out through the Mouth.
3. Drought Lake Level a minimum of 0.15 M AHD
The Lower Lakes during dry periods when the levels reach 0.15 M AHD the gates to be opened and allow sea water in to prevent levels dropping further. Gates during those intermediate dry years then only allow enough fresh water to be used to prevent hyper-salinity not water level. i.e. operation changed from maintaining levels to maintaining salinity below a set level. When there is plenty of water, levels could be maintained at present level of 0.75 M AHD if required.
4. Lake Albert
Lake Albert to become a transit lake by constructing a channel to the Coorong with an automated gate to allow flushing.
Hi Sean,
Re, “Professor Tim Flannery has a title just like yourself” so, grow up Sean.
Re, “The only one that did contribute in these years you left off the list FINNISS RIVER” my apologies I didn’t mean to leave out the Finniss.
Re, “When have I said the Barrages were to be removed” no you have never called for there removal but you do advocate allowing seawater to enter through the Barrages which I will continue to oppose at any cost.
Whilst I agree with 1, 2, 3, 4 we need the proper investigations before any of the measures other than 2 are undertaken.
Hi Ian,
Thanks, “Hi, Peter, welcome to another session of honest toil in the bimbosphere” we mere mortals can but continue to fight the mis representation.
Peter,
Glad to see you practice what you preach to others.
Just to ensure that Jennifer no longer has an excuse for not responding to the more relevant issues, here are the same numbers I mentioned in my post of 27/04/12 3.00pm.
Total pan evaporation 1565mm, times multiple of 80% equals 1252mm less 468mm of mean annual rainfall = 784mm net, which over 75,250 = 590,744 ML. My submission also provided the same analysis for a 1st decile rainfall year.
So would it be correct to say that Ian Mott has calculated evaporation from the Lower Lakes to be in the order of: 1252mm per year.
Can you now convert this figure to gigalitres for me?
So I can get some idea of how much water you think is evaporated from the Lower Lakes in total each year in a measurement we are more familiar with? I just want an evaporation figure, not a partial or total water balance figure.
It’s Ian saying 590.744-Gigalitres?
Are you going senile or something, Jennifer? As I posted above, net evaporation is 784mm in a mean rainfall year. Farmers have no trouble recognising this as 7.84 megalitres/ha which for the 75,350ha area of the lakes amounts to 590,744 megalitres, a very significant drop from your “up to one million ML”.
If I used your 75% multiple to adjust from panevap, instead of my 80%, it would be 1565mm x 0.75 =1174mm which, after deducting the 468mm of MARF is a net 706mm which, over the 75,350ha would amount to 531,971ML.
In a 1st decile rainfall year (1 in 10 year drought) this total only rises to 685,500ML under the 80% multiple or only 626,723ML under your 75% multiple.
Now could you kindly stop this blatant obfuscation and explain why you have, as the courts have defined, made a gross misrepresentation of the facts. That is;
You have made, “such a partial and fragmentary statement of fact that the omission of that which is unsaid renders that which has been said totally untrue”.
And then you can explain why you have allowed the public to believe that this mythical million megalitres of evaporation savings is available every year when the reality is that it would be only marginal in a 1 in 10 year drought and only of significance in an extended 1 in 50 year drought like the last one?
You may only want a raw evaporation figure but the truth demands a net figure because it is only the net figure that can possibly be saved. And even then, only if the river is not flowing and rainfall drops below winter evaporation.
Ian,
You keep flipping and flopping and changing the figure! Not a good look.
Just before you wrote that evaporation was 1252mm and now you are saying it is 784mm?
Output from the most recent CSIRO model and also three earlier studies of evaporation from the Lower Lakes which used different techniques including pan evaporation indicate evaporation rates from the Lower Lakes are in the order of 1,171 to 1,445 mm per annum. You can find the relevant CSIRO references etcetera here: http://www.mythandthemurray.org/calculating-evaporation-from-the-lower-lakes/
You accuse me of misleading when all I do is use accepted methodology for calculating evaporation from water bodies, to come up with a figure comparable to everything that has been published.
Ian said April 28th, 2012 at 11:14 am:
“If Tony was capable of interpreting a table he would know that the BoM tables also display a similar change in pattern for Victor Harbour.”
Ian – there you go again! You just can’t raise your discourse above ranting and insult can you? I CAN SHOUT TOO – which rather proves my point.
If you were capable of reading the information on the WillyWeather web page you’d know that the tide data for Goolwa Beach is actually BOM data for Victor Harbor:
The Data
Tide times data has been adjusted for daylight saving where and when applicable. WillyWeather interpolates its tide times for many locations by converting the tide forecasts provided by the Australian Bureau of Meteorology for standard ports, and data from the Australian National Tide Tables. The tide times on the Goolwa Beach tides page have been adjusted by 0 mins for low tide and 0 mins for high tide to the official tide times for Victor Harbor. Tide height data is for Victor Harbor, no adjustment has been made.
http://tides.willyweather.com.au/sa/fleurieu-peninsula/goolwa-beach.html
I can not only read a tide table, I can avoid cherry-picking periods shorter than the lunar cycle to “prove” my argument. You consistently refer to tidal range, though anything above MSL cares not a tinker’s cuss what the tidal range is, but peak tides. Though the data on your favourite tide site has a coarse resolution of 0.1m ( BOM says Victor Harbor is consistent with the Murray mouth), it’s within +/- 5 cm of the BOM data, so I can use the WillyWeather charts for quick analysis. Over the period 1st April to 28th April, peak tides were as much as 0.6m above MSL, almost double the 0.35m your tidal range suggests.
Your statement
“There is generally only one tide each day, and that is only during the 50% of the lunar cycle when they even take place at all. And, aside from storm surges, they only exhibit a tidal range greater than 70cm on 4 or 5 days each month.”
bears little examination. “When they even take place at all” is saying that there are no tides whatsoever for 14 of the 28 days? You need a reality pill, or to take off your blinkers. There are two distinct tides, though often of disparate heights for 14 of the 28 days 1st-28th April 2012. Minimum daily tidal range is 0.3m, maximum is 1.1m, peak tide is 1.3m. I’ve estimated MSL as 0.7m which is being generous, and means that peak is at least 0.6m above MSL, and there are 8 other days with identical peaks.
Not that it really matters, as I’ve said, but there are 11 days this month with tidal range OVER 0.7m, not “4 or 5”. I invite anyone to count them. March 1-28th shows 12 days over 0.7m range. Portland VIC exhibits very similar data and tidal characteristics when I compare it with the WillyWeather charts, generally within +/- 5cm on any particular day, and I’ve posted hourly charts for Portland covering 1-14 Feb, split into two periods to show the tides clearly here:
http://2.bp.blogspot.com/-b2wY9zm6DTw/T50bqsvBePI/AAAAAAAAAxQ/Lxg5ecMJ3hM/s1600/Portland+VIC+Feb+01-14+2012+Hourly.gif
http://3.bp.blogspot.com/-9oJarv3pfAM/T50bqpQFnsI/AAAAAAAAAxU/UBCC3hnElLs/s1600/Portland+VIC+Feb+15-29+2012+Hourly.gif
Data trumps blinkered bluster anyday.
More sleaze and shimmy from Jennifer. Readers can see for themselves that I referred to both in the same sentence. They will also observe that you are using this as a device to avoid answering all the more relevant questions, like why you apparently think the public have no right to ALL relevant information, not just the factoids you choose to give them from the drop down menu.
And if Tony Price did not have a serious retention deficit he would have recalled that I directed readers on how to go to any point on the calendar and arrow through a full monthly sequence of tide graphs or more. And I gave specific direction to observe both April 2012 and October 2011 to get a better picture of the annual variation. But this doofus accuses me of cherrypicking.
And gee wiz, he went all the way to Portland Vic for what he apparently believes was broader confirmation. Try checking out the patterns for Gippsland, Eden, Pt Kembla and Yamba on the East Coast, where a peak tide is 2.5 metres, there are two each day, and they are much more symetrical, and you might start to figure out why I might regard a 30cm tide as not being a real tide at all.
Note that the further from the mouth we go the more the tide signal is degraded. So a 30cm tide out on the ocean will only be 20cm inside the mouth and only 10cm at the barrage. And the narrower and shallower the mouth becomes the more degraded the signal becomes.
Readers will by now be starting to recognise Price using the same MO as Jennifer. Launch into a protracted contest over syntax while ignoring the key elements at issue.
Are the tides generally asymetrical or not?
Does that asymetry involve a shorter period of rapid inflow followed by a longer period of outflow?
And does this differential speed of flow produce greater inflow of sand than the outflow is capable of removing unless outflows are augmented by large volumes of fresh water?
And in the absence of the pre-barrages 12 million megalitres of irrigation water, how can the removal of barrages facilitate a properly functioning tidal regime if the mouth has already closed?
And by the way, hot shot, were there any storm surges in the April data? You do recall, I hope, that I said “aside from storm surges there are only 4 or 5..” You do understand, I hope, that tide tables are revised to incorporate prevailing weather? And you do appreciate, I hope, the probability of storm surges in April?
I think Ian Mott is a tosser.