PASSIONATE about the wine industry, Philip White grew up in the Bremer Valley of the Lower Murray. He now lives on the opposite side of the South Mount Lofty Ranges at McLaren Vale. He tastes wine and writes about wine, and the wine growing regions of South Australia. 
Today he was judging at the inaugural Currency Creek Wine Show. Currency Creek empties directly into Lake Alexandrina. Mr White describes it as, “A small, but very pretty appellation on an estuarine river system flowing into the lakes at the mouth of the Murray.”
And I love his description of the Currency Creek region more generally:
“Cross that range and you’re in rain shadow country, where Currency Creek and its neighbouring stream, the Finniss, flow out of Mosquito Hill country, Cox’s Scrub and Ashbourne, toward the south-east. Into the Murray estuary.
Over that way the stones are more aggro and tortured, and vary from the heavily-mineralised metamorphic schists of Kanmantoo, where I grew up on the Bremer River, to the intensely-varied fruitcake of chaos some big glacier dumped where the Finniss escapes the hills. It’s highly picturesque, from the almost English pubbiness out Ashbourne way, with European trees (just outside the declared region), to the wild reaches of samphire and reeds between the old river ports of Milang and Goolwa.
The vineyards seem largely to have been planted on the alluvial sands and clays of the sedimentary flats, and some terra rosa over limestone, but some have been more adventurous. Dr. Berthold Salomon, the Austrian winemaker, planted upstream on a rocky fruitloaf of glacial moraine: the complexity of the many ancient geologies shaved up, transported and dumped by massive ice has given him a multi-epoch pudding of stones of myriad mineral flavours and water-retaining capacities. A moraine terrine terrane, if you like. In these ancient parts, these are my favourite geologies for viticulture. Gimme chaos; get complexity.
But I’ve been up and down that eastern side of the range with him, licking rocks, finding the ones with the flavours that best match home.”
Mr White is not only still excited by the topography and geology of this region that borders Lake Alexandrina to the southwest, but he is also fascinated by the notion of opening the barrages.
Just yesterday he wrote at his blog:
"While the debate about the Murray-Darling reaches anarchic crescendo, there is a persistent and increasingly laudible argument that the barrages be removed from the Murray Mouth. These are a series of weirs which secure the freshwater coming downstream by holding the saltwater of the ocean out. It’s supposed to be like a dam, with the fresh river water flowing over the barrages and into the ocean. Recently, it’s been the other way round, with seawater leaking back through to the dirty polluted puddle of droughtwater within. Diluting it, if the truth be known...
“The history of our estuary has been a long string of unfortunate mistakes…
Now it has some reasonably fresh, if not exactly clean, water in it, the river system is being provided a short breathing space for these estuarine industries: down this end, dairying is also vital, but entirely dependent on a good supply of fresh river water.
The thing that scares me about all this is the ongoing popular presumption that the floods are somehow normal. These floods are not normal. Drought is normal. And ongoing.
I discussed this recently at Burra with the radical Natural Sequence Farming genius, Peter Andrews.
He pointed out that during the white exploration of its coastlines, Australia’s rivers were barely visible: there was no mighty Mississippi or Nile Delta emergent, and no surge like the hundreds of kilometers of freshwater that whoosh into the South Atlantic where the Amazon emerges from its jungle.
"The rivers here hardly ever made it to the sea,” Andrews said. “The water stayed in the country and kept it good. The rivers were explored from the interior. Somehow we’ve got to remember what it was like before us. We’ve got to learn to spread the water out, use it where it falls, take its energy and destructive force away, slow it down, and let it fill the country while cleaning and draining it in its own complex way. Slowly. If there’s any left to flow into the ocean, that’ll be good.”
And along these same lines I’ve written that if the current water reform process is truly about giving back to the environment, then we should be thinking back to a period before rivers and creeks became constricted by sheets of water running off compacted soils, before swamps were diverted, before river de-snagging and before the blasting of rock bars for paddle steamers.
As historian Bill Gammage notes in The Biggest Estate on Earth: How Aborigines Made Australia back in the dreamtime shallow streams and overflows flushed more of Australia, filling billabongs, swamps and holes, and recharging springs and soaks.
That was a time when the health of a landscape was measured less by how much water was in a river, and more by how many kangaroos it could support.
In 1901 James Cotton, a Cobar pioneer, wrote that before the district was stocked with sheep and cattle it was covered with a heavy growth of natural grasses and that the ground was soft, spongy and very absorbent.
Overstocking was a problem throughout the Murray Darling Basin particularly during the late 1800s resulting in significant land and water degradation. Overstocking transformed soils in many districts from soft and spongy to hard clay that, instead of absorbing water, caused the rain to run off in sheets as fast as it fell – to again paraphrase Mr Cotton.
In the past one hundred years there has been a gradual improvement in land management. Stocking rates have fallen, some native grasses are returning and there has been a move to minimum tillage conservation farming practices. This has resulted in a general improvement in soil structure.
The ground may not be as soft, spongy and very absorbent as it once was, but there is no doubt that when the rain now falls on the Murray Darling, much less water runs off into adjacent rivers and streams than it did one hundred years ago. This must have implications for the amount of water flowing to South Australia.
Indeed a truly healthier Murray Darling Basin would mean less water for South Australia and as I’ve argued repeatedly, don’t waste what’s left on the dammed Lower Lakes; certainly not on the Lower Lakes during drought. Instead let’s open the barrages, or at least remove the Mundoo barrage, and let these coastal lagoons fill with some seawater as once happened naturally each autumn and for longer periods during drought.
Mr White is not frightened of the idea. And if the salt water should on occasions extend beyond the Lakes and as far up the river proper as Jervois, where the off-takes for the irrigation pipeline begins, Mr White suggests that:
“They simply shoved a pipe into another place further upstream where the water was better, pumped her down and kept irrigating…”
Why not!
******
Read about Philip White and good wine at http://drinkster.blogspot.com.au
More specifically at
Tasting the End of the River
An anticipatory Mediation
Of A Brand New Wine Region
By Philip White
read about the Barrage Removalists, link here
http://drinkster.blogspot.com.au/2012/04/up-next-currency-creek-wine-show.html
And you can post a comment.
********
PS
Interestingly the blog post by Mr White links to ‘A fresh history of the lakes: Wellington to the Murray Mouth, 1800s to 1935’. This 2004 report certainly provides a lot of useful historical information about the Lower Lakes and how they were often fresh before the barrages. But the same report omits so much information to the extent that it denies Lake Alexandrina was once the central basin of a wave-dominated barrier estuary. If you are interested in a longer history consider my report ‘Plugging the Murray’s Mouth: The Interrupted Evolution of a Barrier Estuary’ that is available for download here:
https://climatelab.com.au/wp-content/uploads/2012/02/Plugging-the-Murray-Rivers-Mouth-120212.pdf
And there is also my recent submission to the Murray Darling Basin Authority here:
https://climatelab.com.au/wp-content/uploads/2012/04/MDBA_Submission_Marohasy_Abbot_April16_2012.pdf (sorry this is 10Mb)
Since you mentioned AHD, " the period when tide was above the AHD level of the South Lagoon", you don't know either of these, that is the level wrt AHD of the surface of the South Lagoon, nor (more importantly) how tide-gauge zero and therefore tide height relates to AHD. It's clear from your assumptions that you don't. If you do, explain for all us "doofuses".
I like this game, the more I look the more I find - I spotted this one a while ago, but kept it in reserve. Since you mentioned both Jennifer AND evaporation:
2.48 The North Lagoon is 48km long. Its average width at AHD is 1.5km, depth is 1.2m, surface area is 7,200ha and volume is 86,400 ML (CFMI , 1992). Mean annual pan evaporation is 16 ML/ha so the actual (80%) is more like 12.8 ML/ha. Mean annual rainfall is 5 ML/ha giving a net evaporative loss of 7.8 ML/ha. It requires an average 56,160 ML each year (65% of volume) to replace net evaporation losses.
SFSG (so far so good) Mean annual rainfall is 5 X 7,200 = 36,000 ML (remember this figure), net evaporation loss (evaporation - rainfall) = 56,160 ML.
2.57 When the historical average 77 annual storm events were included, at an assumed median height increase of 20cm and of 24 hour duration, the total annual inflow was estimated to increase by 25% to 228,200 ML or an average 625 ML/day.
2.58 Add the mean annual rainfall of 36,000 ML and the total water increment would be 264,200 ML/year. Deduct the evaporation loss of 56,200 ML and we are left with a minimum net injection of 208,00 ML each year, or a 240% turnover of the original volume. These 2.4 complete exchanges of volume each year will deliver in full, and well, the ecosystem services that a much larger volume of fresh water spilled over the Barrage does only partially, intermittently, and poorly.
... but the evaporation loss of 56,200 ML (56,160 ML in 2.48) has already taken rainfall into account, it's a NET evaporation loss. Ian's added the rainfall in TWICE.
No wonder Ian had a go at Jennifer over evaporation as opposed to net evaporation figures. If she'd added it in ONCE, it wouldn't have been enough for him.
Price is still clutching at straws with what he thinks is a relevant argument about the difference between Willyweather and the BoM data for Victor Harbour. But the reality is that the scale of storm surges on inflow volumes, when applied to a full month of tide values, (not 2 days, doofus)and applied to only the period when tide was above the AHD level of the South Lagoon, was found to increase total flow volume by 50% for an assumed storm increment of only 20cm.
This was why I identified the need for more detailed examination of the full range and frequency of actual events in the section "4.00 What else do we need to know?"
The submission made it ABSOLUTELY clear in the 1.0 General Principles section that the proper exercise of power by the MDBA went beyond the mere consideration of matters raised. It also extends to conducting proper (ie more detailed) examination of any relevant matters it may become aware of. It never set out to be a complete report, and at no stage have I ever held it out to be such a definitive statement of fact.
And Price is not acting in GOOD FAITH by suggesting that this invitation for the MDBA to further examine a relevant matter had an obligation to be 100% accurate. Has this goon seen the entire page of disclaimers that normally prefaces CSIRO reports that have had the benefit of substantial funding and major in-house resources?
Indeed, given the disparity between Jennifers claims of 1 million megalitres of saved evaporation from Lake Alexandrina and the squalid reality of zero savings while ever annual river flows exceed a very modest 600,000 ML, it is clear that Price is a first class hypocrite.
More importantly, a firm calculation of the actual volume of inflows through pipes is far less relevant than the fact that inflows will vary to match whatever tide maximum occurs on any day. The higher the tide peak the greater the difference between outside and inside water levels and the faster the flow will be in response. Once again, Price thinks he is on to a critical point but the reality is that he is only up yet another blind alley for the ignorant.
And the fact that his only recourse, in filling in the gaps in his understanding of the issues I pointed out in previous posts is to demand that I enlighten him, only highlights how out of his depth he really is. I have no problem explaining, eventually, but only after this goon has shown us all a clear record of what he thinks is the case. Price has a date with his own stupidity and I want a permanent record of that stupidy. So go for it, doofus.
The irony is that local MP for the region, Patrick Secker, on hansard for the Windsor Committee, estimated the cost of a pipe to be only $30 million each. I made no cost estimate of my own because I am not an engineer. But even if Secker is out by 100% and each pipe costs $60 million, they will deliver the same 3 million megalitres of sea water a year in perpetuity for $180 million that the MDBA already has a budget to deliver intermittently with $6 Billion worth of buy-back water.
And this Price (Prize) freak show has the gall to work himself into a lather over the variance between Willyweather and BoM tide records? Talk about lost the plot.
I'll be updating my "Murray mouth" post with bathymetric charts and links, and anything I consider relevant later today, for example the significant effect of barometric pressure on sea level. I'll then restructure it with inline links to sections, links to other sources, rename it and elevate it to a fixed reference page linked at the top of the sidebar. It should prove to be a useful resource as it grows. If you have any suggestions for content, please leave them here, or better, on the response thread (or both, if you have the time and inclination):
http://mostlyharmless-room-101.blogspot.com/2012/05/australia-murray-mouth-effect-of-tides.html
As usual, Ian uses the weapons of the intellectually barren to attack the messenger first, and then attack what they didn't say second, and produces "straw men" from his hat with a wave of his wand.
Here are a few examples from his last comments:
"He has no idea how a 5m diameter pipe could flow into a water body that is only 2m deep. But instead of asking how, he listed it as a flaw in my logic."
Why should I ask how? The onus is on the author of a proposal to utilise pipes to explain it, and in the proposal, not in a blog thread. Whether it's a flaw in his logic or not, it's a glaring omission in his submission.
"He had no idea how a pipe could allow water to flow through it without bringing sand with it, but instead of asking, he listed it as a flaw in my logic.".
I indeed do, as with power stations' water inlet pipes, but it shouldn't be up to me, or any reader of his submission to provide a solution, but the author of the document, something he's signally failed to do.
"He had no idea how to make a simple one way valve on a pipe, but instead of a asking, he listed it as a flaw in my logic."
I indeed do, but not with pipes up to 6.4m diameter, where the valves or flaps must needs weigh many tons, and be a costly component of the installation. It shouldn't be up to me, nor any reader of his proposal to know how to scale up a "simple valve" to the size and weight implied, but for the author of the document to know it, to explain it and equally importantly at least have a stab at the design and likely cost, which things he's signally failed to do.
"Is she prepared to explain to us how large waves behave when they enter an estuary? Or is she still claiming that there is no change from the way large waves behave when they hit a beach?"
Ian hasn't explained or quantified this anywhere, yet challenges someone else to do so.
"Is she prepared to enlighten us with her own understanding of how river outflows alter sand deposition volumes?"
Ian hasn't explained or quantified this anywhere, yet challenges someone else to do so.
If someone's intending to identify an engineering solution to an environmental problem, it might be expected that that person display some knowledge of, and some skill in, both disciplines. Ian has displayed little of either in both. I say displayed advisedly, as he's clearly no "vacuous moron" as he described me, but the "vacuous" part applies as he leaves us in the dark, to ask questions about the detail.
He didn't know that the WillyWeather tidal predictions (produced using a computer model) were actually for Victor Harbor. He didn't read the warning there that the data there wasn't "accurate enough for scientific purposes". He chose to use data for only 2 days out of 365 to calculate flows, and to effectively extrapolate his calculated flow rates over a full year, when the period he chose doesn't represent that year, let alone any year.
He didn't show any bathymetric (depth) data for the mouth or channels, lakes or lagoons, or the very relevant seabed , something that would be considered to be essential for a scheme which proposes to pipe water from some distance out, above that seabed, and into the watercourses.
He didn't even attempt to analyse the direct consequences that an injection of sea water into those watercourses would have (not even their levels), something that would be considered to be essential for such a scheme. In his flow calculations, he implicitly assumed no change in level in those watercourses, a major error, as such an increase in level reduces flow as it proceeds.
He finishes:
"Or will she [Jennifer] continue to avoid any statement that might tell us all what little she actually understands and how callously she disregards any evidence that challenges her ignorant whimsies."
Ian says "instead of asking" a total of 5 times here. He has written a proposal, which purports to be a detailed solution to a problem, and leaves the reader to ask important questions not answered therein? Ian has the "don't ask it'll work fine when we do it and any problems can be solved along the way and by-the-way we haven't costed it" approach of the simplistically minded to geo-engineering "solutions".
Ian has displayed in all that he's written here, on his blog, and in his submission, how little he actually knows, or at least is prepared to tell us, for he tells us very little at all of substance, and leaves us to ask questions instead. A solution is supposed to answer questions, or at least to suggest answers.
Ah, it all makes sense now. I was under the impression that Price was from some sort of honourable profession like farming but the reality is that he is nothing more than a pensioned off departmental boofhead. And what readers have been given is a very good example of the way bureaucratic low life can breach the trust placed in them and abrogate their duty to consider all issues in good faith.
He claimed he "knew a bit about tides" but then proceeded to claim that a larger tidal prism would not produce faster tidal flows through the same channel.
He had no idea how a pipe could allow water to flow through it without bringing sand with it, but instead of asking, he listed it as a flaw in my logic.
He had no idea how to make a simple one way valve on a pipe, but instread of a asking, he listed it as a flaw in my logic.
He favoured a flow that went the other way, ignorant of the fact that such a passive flow could only work during the lower half of the tide cycle, and not at all during storm surges, and could only then result in a substantial lowering of the Coorong's water level.
He has no idea why a continuous inflow of sea water will NOT lead to a major increase in Coorong water level that would impair the efficiency of pipe flows. But instead of asking, or even reflecting on it for a few minutes, he listed it as a flaw in my logic.
He has no idea how a 5m diameter pipe could flow into a water body that is only 2m deep. But instead of asking how, he listed it as a flaw in my logic.
And he has no idea of the concept of opportunity cost, that the upper limit of what could be spent to keep the mouth open with sea water would be the value of the fresh water they wish to buy back and the value of the losses such a buy-back would inflict on the basin community. But instead of asking, the dumb turd listed it as a flaw in my logic.
Price never intended to consider anything I have said with an open mind. His selective quoting out of context and deliberate misintepreting to produce straw men is as painfully obvious as it is tediously repetitive. I don't intend to redress any further gaps in his knowledge because he needs to place the full sum of his ignorance on display for all to see before any further response. Educating the village idiot can only end in tears.
And as for the merit of my submissions, they have clearly been intended to serve two purposes. Firstly to inform the policy process on an issue that has not had proper consideration. And secondly to provide sufficient understanding of the need for further investigation. But this bile soaked nutter then has the gall to complain that my pro-bono efforts do not meet the standards of a full engineering feasibility study, the cost of which would leave little change out of a million bucks.
Readers will now have noticed how Jennifer has consistently declined to substantiate any of her assertions. Does she agree with Price's penetrating insights into flow rate responses to larger tidal prisms?
Is she prepared to explain to us how large waves behave when they enter an estuary? Or is she still claiming that there is no change from the way large waves behave when they hit a beach?
Is she prepared to enlighten us with her own understanding of how river outflows alter sand deposition volumes?
Or will she continue to avoid any statement that might tell us all what little she actually understands and how callously she disregards any evidence that challenges her ignorant whimsies.
The clown who seriously claimed that a larger prism wouldn't influence the velocity of tidal inflows now runs a desperate attempt to cover his tracks with his standard search for anything he can first misinterpret, and then shoot down his own misinterpretation. But I guess that is the only way such a conspicuous plodder can fabricate a win.
The real classic is he then goes through the section of my submission called "4.00 What else do we need to know?" and then ponces about presenting the same issues as if they were omissions on my part that HE had actually discovered. What a troll.
Readers of that submission who have had officer training will recognise a format similar to what is called a battlefied "appreciation of the situation", the core of any plan, which sets out, among others, essential facts, assumptions, unknowns, alternatives etc. Those with exposure to the planning processes covered in MBA courses will also recognise a familiar format.
And if Price had ever had any exposure to a proper planning role himself, he would also know that any plan should be a work in progress which allows for constant revision and addition of greater detail.
And given that Price is such an expert on MDBA submissions perhaps he would care to provide a link to his own submissions to the MDBA to compare the level and adequacy of his data. Indeed, take a look at Jennifers own work and see who is laying out information to inform and who is flogging spin based on anecdotal references out of context.
And then he has the gall to suddenly discover the relevance of differential water levels after being found to have completely ignored it, no actually rejected its relevance, in an earlier post. I will copy his pathetic post above and reply in detail on my own blog. This doofus is obviously trying to generate some traffic to his own site but I refuse to oblige. But rest assured, the more this clown tries to burrow into the detail the bigger fool he makes of himself. So go ahead, punk, make my day.
I'll tell you why that submission is bad to the point that it's worthless. It contains no actual data on tides, and therefore no data on day-to-day, month-to-month, or year-to year variations. It contains no data on storm-surges other than average number and an assumed increase in water level, which even a cursory study reveals are the events which dump vast quantities of sand inside the mouth and into the channels, and not tidal flow. It contains no maps of any kind, and just one diagram, a fictional diagram of a 1km pipe stretching from well below low tide level, beneath the dunes into the Coorong, of which more later.
There are no bathymetric charts nor data of any kind. There is no account of the topography of the beach, the seabed, the dunes of the peninsula, the lakes, nor the depth of the channels inside the mouth, and most telling of all, of the Coorong, the centrepiece of the scheme. It proposes installing one or more pipes under the dunes to the Coorong with no mention of exactly where. Into the Coorong whose maximum depth is 5m over just a very tiny area. Pipes up to 6.4m bore into the Coorong which is typically 2-3 metres deep over most of its area, and down to a few cm in places. Pipes which would consequently have their "non-return valves" (not described nor costed in any way) half-buried in the bed of the lagoons.
There's an almost anal obsession with minutely detailed but fictional flow rates through the pipes. Fictional because the difference in head of water driving the flow is calculated from an idealised tidal pattern which applies to hundreds of km of shoreline and not from real data for the locality; a head of water which is calculated assuming no change of level inside the Murray mouth, the channels or the Coorong as the inward flow progresses, when of course the head of pressure decreases as the levels inside increase, decreasing the flow. Fictional because the flows are calculated for only two days tide pattern in November 2010, with the assumption that the calculated mean sea level for those two days applies not just to the rest of the month, but to any period, when the actual monthly average sea levels vary over a range whose maximum is 50% greater than the calculated MSL, and whose minimum is 20% less.
Because there's no topographical data on the shallow-shelving beach, the proposed length of pipe(s) would be far too short; waves can be seen breaking as much as 4-500m out to sea on air photographs and Google Earth/Maps, which means that the seaward end of 1km-long pipes would likely be breaking the surface at neap tides, certainly so if they were 6.4m in diameter.
There's an assumption (most of the document is assumption) that tidal flow through the mouth takes a significant amount of sand with it, when there are smooth sandbars and sandbanks and sand islands inside the mouth and channels. Sandbanks and sandbars which aren't covered even by high tides; sand islands which aren't covered by any tides. Clearly none of these got there by tidal flow; neither water nor sand flow uphill. Not none of them will be removed by reverse tidal flow nor river flow through the mouth. The action of river flow is to scour the mouth; river flow can't lift sand from the deeper channels and push it over the rock/sand bar at the mouth. River flow is too slow to scour much sand from the bars and banks, and even if it does, it'll just be moved a short distance closer to the mouth.
Clearly, under normal tidal conditions there's a near equilibrium set up. - some sand sand comes in with the tide, rather less sand goes out with the tide. Normal tidal flow doesn't shift much sand; if it did there'd be sand piling up daily on the beaches all along the peninsula. Storms shift sand through wind and wave action and much higher sea levels due to the combination of wind and low atmospheric pressure. Storms have created the sandbars and banks and islands, and the bordering dunes themselves. A 1-millibar (hPa) reduction in pressure causes a 1cm rise in sea level. Reductions of 10-30 hPa are common during storms, possibly more during full-blown tropical storms.
There's a statement to the effect that additional river flow provided by releases of (valuable and expensive) fresh water won't shift much sand (I'd say virtually none), and that the effect will be to do little more than scour the mouth (without once using the word "scour" anywhere). and widen it, and that this will make the mouth more prone to sand influx during storms. I accept this in the absence of contradictory evidence, it seems perfectly logical. What I don't accept is that additional flow out through the mouth, as a consequence of introducing more sea water through pipes, and therefore over longer periods than currently will not do exactly the same and to a greater extent - widen the mouth and make it more prone to sand influx during storms. This is entirely overlooked in the justification, it can't be denied, and is a serious flaw.
Many statements, assertions and conclusions contradict one another throughout. The few references used to "support" some conclusions do not in fact support them, as I mentioned in an earlier comment. Worst of all, there's a whole section at the end which details much additional data which is needed to make a proper job of it, most of which I've mentioned above as missing entirely. You can't make bricks without straw, and you can't produce a detailed submission without essential facts and data.
BTW, Ian's "flow rates" were based on TWO days out of the 2 WEEKS he "analysed". What does WillyWeather (Ian's only data source) have to say?
Tide Clock Accuracy
The online tide clock displays the current tide for Goolwa Beach as supplied by the Bureau of Meteorology using methods of interpolation and offsets provided by the Australian National Tide Tables. Actual tide clocks such as those available through the store on this website are not accurate enough for scientific purposes as they do not take into account the gravitational effects of the sun, or changes in atmospheric pressure which may alter the state of the tides. Please note that in some areas, the gravitational effects of the sun are similar in magnitude to that of the moon.
I'm currently writing a paper on "The Climate of the Murray-Darling Basin and Lower Lakes" based on two days weather forecasts for Victor Harbor in November 2010.
There Ian goes again - he doesn't know what I know or don't know, and he doesn't know what I have read or not. I have almost finished a detailed critique (which I will post on my blog) of his submission, which is almost entirely unreferenced, despite my initial impressions. In his comments here, Ian has been citing his own work in support of his arguments. Listing a few publications at the end cuts no ice with critical and informed readers. Under peer review, this submission wouldn't get beyond the waste bin in the Journal's post room.
His submission had not, and has not, a cat's chance in hell of being taken seriously by anyone with any knowledge of hydrology, or tides, or the cost of construction, or the depth of water in the Coorong. It's a submission that most peculiarly for the subject matter, doesn't contain the key word "scour". It's a proposal to install pipes to increase sea water flow beyond the Murray mouth and under the peninsula to the Coorong, yet contains, for example the astonishing statement
2.74 Precise estimates of the likely cost of installed pipes are beyond the scope of this
paper...
Reply: And you expect this submission to be taken seriously?
2.09 When sea water can be substituted for fresh water the limit to the annual cost of any
infrastructure required in its capture, transportation and delivery to the place of use is
defined by the spot price/ML of the fresh water it is replacing. The capital cost of
infrastructure for the delivery of sea water is defined by the market price/Ml of a
fresh water allocation, plus an additional premium for the substantially improved
reliability of sea water supplies.
Reply: The capital cost of infrastructure for the delivery of sea water is defined by the capital cost of infrastructure for the delivery of sea water, and nothing else. It has nothing to do with the price of fresh water.
2.10 The difference between the market price of fresh water and the delivered cost of sea
water is the marginal profit from the substitution process. The gross profit from the
substitution is the marginal profit x the volume of all fresh water supplied.
Reply: The difference between two costs is not profit, marginal or otherwise.
2.01 A purely hydrological function like the transportation of sand and sediments can be,
and currently is, performed with equal effectiveness by equal volumes and velocities
of sea water or fresh water.
Reply: This statement is in a submission which makes much of the imbalance between inflow and outflow volumes and velocities. It can also be performed with equal effectiveness by differing volumes and velocities of sea water or fresh water.
2.52 A detailed analysis of the two kinds of tidal patterns shown in the graph at 2.13 above was conducted for the period from 6th to 20th November 2010. This covered a full week of each pattern and is considered to be a reasonable approximation of the other twenty five fortnights in each year.
Reply: The "tidal patterns" are taken from tide predictions for 2 weeks, and not from observations, which can and do differ markedly from predictions. The 2 weeks are extrapolated to 52 weeks, and by inference to any period at all. This is considered to be a "reasonable approximation" without any justification whatsoever. Monthly data for Victor Harbor just for that year shows how wrong this "reasonable approximation" is. Other years differ from 2010 markedly. All the detailed calculations are based on the extrapolation, and have not (and cannot have) taken into account essential data on the water level inside the mouth at any time. The whole thing's a house of cards, with the calculations as one of the bottom cards.
Compare and contrast this with
4.01 The average duration of storm surges, (i.e., the time taken for frontal systems to pass)
and their range of variation, needs additional study, as does their mean height and
their range of variation in height. Without this information the more accurate
determination of the likely range of passive flow pipe yields cannot be made.
Reply: This important and neglected factor indeed "needs additional study", for without it the "house of cards" has one of the bottom cards removed.
2.81 Many people, including myself in the past, have criticised this evaporative loss as a
waste of fresh water which had formerly been supplied from tidal flows. But this is
based on a misconception that past sea water in tidal inflows was at the surface and
extended to cover most of the lake surface. In fact the colder, denser sea water would
have intruded under the warmer, fresh water and, even with no loss of tidal signal,
would only have extended to 30% of the lake area.
Reply: Remember his lecture at Debbie above? "Twice the prism, twice the flow"? 2.81 says that tidal influx wouldn't even extend to 30% of the lake area. This says the exact opposite, supported by
2.36 In reality the slope of a tidal inflow is much less than half the tidal range. The natural
tidal flow has difficulty fully supplying the potential tidal prism. Flow distance is
critical. The further from the mouth the greater the variance between the potential and
the actual prism as the tidal signal gets weaker and weaker.
... which is (with 2.81) the true state of affairs, AFAIK.
2.36 & 2.81 conflict fundamentally with "increase both the volume and velocity of inflows" here:
2.83 Calls for the removal of the Barrages, including my own in the past, have been based
on the mistaken belief that this larger tidal prism would produce larger flows through
the Murray mouth that would then help maintain the mouth in an open state. But the
tidal asymmetry shown at 2.13 above makes it clear that a larger prism would simply
increase both the volume and velocity of inflows but maintain the imbalance with the
volume and velocity of outflows. The result would be an increased potential and
incidence of deposition inside the mouth.
5.44 With this direct injection of tidal water into the Coorong system the full suite of
environmental values and ecosystem services can be maintained with a substantially
higher level of certainty. And the system can be maintained in a circumstance that
remains connected too, but is no longer dependent on, the vagaries of Murray mouth
hydrodynamics.
Reply: Gobbledygook.
Most of the very few direct references used in support do not in fact support the assertion:
2.20 The maximum potential for deposition of sand within the Murray mouth is when mean sea level is highest. According to Webster (2005),
“The modelling and measurements presented by WBM Oceanics (2003) show that this transport is likely to be particularly intensive under conditions of high waves and spring tides.”
Reply: Webster doesn't say anything about MSL in this quote, but "high waves and spring tides” - not the same thing at all, and arguably the exact opposite.
2.33 According to Webster (2005) only the long term trends make it into that system.
“Low frequency water level variations in Encounter Bay, such as those
associated with the passage of weather systems, penetrate more effectively
through the mouth and along the Coorong than more rapid level fluctuations
such as those due to the tides. Similarly, the width and depth of the mouth affect
its ability to transfer water level fluctuations into the Coorong.”
Reply: It's perfectly clear the quote doesn't support the assertion at all.
Included in this submission is a proposal to install a 5m diameter pipe under the dunes (the peninsula) from the sea to the lower Coorong. There is no mention of the critical factor of depth of water.
2.70 Larger Diameter Pipes will obviously deliver more water more efficiently. An
increase in diameter from 3.6m to 5.0m almost doubles the cross section but in the
tidal constraints present at the lower Coorong the volume of inflow will increase by
237%.
The maximum depth of water in the Coorong is about 5m, in the lower Coorong it is much less. Enough said, I think.
I'll provide charts and other data of course. I've enjoyed this exercise. For more than a decade I was critically examining proposals to spend lots of money on schemes whose merit ranged from "clearly of benefit" to "better to dig a hole and shovel the money in". I leave readers to judge what my assessment of Mr.Mott's submission would have been then, and is now.