The plan for the Murray-Darling Basin was released a few days ago, complete with a very nifty “knowledge base” that indicates where the MDBA got its data from. As Quiggin explains, the plan calls for about 3,000 to 4,000 gigalitres per year to be returned to the river:
Here’s the rough arithmetic on the irrigation side, which is broadly consistent with the modelling done by my Group, some of which was used along with research by ABARE in preparing the draft plan. A 30 per cent cut in water use will result in a 15 per cent reduction in the gross value of agricultural output, and a smaller reduction in net returns to farmers.
…Now that the drought has broken, I’d guess the likely price for entitlements will be around $1500/ML suggesting a cost of buyback (or similarly cost-effective conservation) of between $4.5 billion and $6 billion.
Irrigators are predictably furious, overflowing meetings with protests and taking the mickey out of the Authority’s website. At issue, with all reforms like this, is the level of job losses, with irrigators heavily disputing this claim in the Guide:
A fall in Basin-wide employment of around 800 full-time jobs (if 3,000 GL/y is adopted) would be expected
Some of the claims of job losses in the tens of thousands are simple scaremongering; however, net job loss figures of that kind hide a lot of pain as old jobs disappear and new jobs emerge, often in different geographic locations and requiring new skill sets and aptitudes that many existing workers in the Basin won’t possess. Even so – what alternatives are out there?
It seems Tony Windsor – the only one of the rural independents whose electorate lies partly within the Basin – wants to consider a few:
Mr Windsor said he would conduct an objective valley-by-valley analysis of where the authority’s recommended cuts to water allocation could be tolerated. He said that where the risk of a significant socio-economic fallout was high, “there may be other strategies to fixing this not identified by the authority”. He said “the political process” would examine these and other issues in the coming months.
Mr Windsor said the MDBA should not allow water to be taken away from irrigators on account of climate change, because they were not responsible for the problem.
“If part of this (debate) is that there has been a human-induced climate change, is one of the solutions to bring water from areas where there has been a human-induced addition to the water system?” he said. “I think it’s something that we should consider in the debate for the climate change component.” He said the feasibility of the proposal was unknown, but some north Queensland catchments could be possible water sources. Mr Burke said that no suggestions would be ruled in or ruled out at this stage of the consultation process, and any ideas put forward by Mr Windsor would be considered.
Ah, let’s just get some water from somewhere else. Sounds great – Except that if water was conveniently available from somewhere else, we’d probably already have sourced it.
The most “realistic” of the proposals to get additional water into the Murray (excluding abandoning the commitment to restore flow to the Snowy River, which in any case wouldn’t add very much) would be to divert water from coastal rivers in northern NSW – for instance, the Clarence River. As, again, Quiggin notes, water is heavy. Pumping gigalitres of the stuff across the Great Dividing Range is going to require a great deal of very expensive infrastructure and a lot of energy, only some of which you can recover on the way down with a hydro plant. And, of course, the locals in the Clarence catchment aren’t exactly thrilled about the environmental consequences of the proposal, which was last floated before the 2007 election and was opposed back then.
But what about the more “ambitious” proposals to take water from Far North Queensland and put it in the Murray? Let’s ignore, for the moment, the environmental and political impediments (Wild Rivers, anyone?) and just consider the engineering and cost aspects. For instance, consider this proposal to put water from the Burdekin River in floating plastic bags, drift them in the current down the east coast of Australia, and pump them to Jindabyne or Eucambene in the Snowy Mountains to put it into the Murray-Darling. This was put forward as a “cheap” alternative to piping water from the Burdekin south; estimates put forward by the Queensland government give numbers from $7 billion up just to get water to Brisbane.
Anyway, how much does this “cheap” plan cost? Based on the author’s back-of-the-envelope calculations (almost certainly an underestimate) he figures $2 billion in capital costs, plus the cost of electricity to pump the water 1.2 kilometres to the top of the Snowies, for 365 GL of water per year. Even ignoring the pumping costs, however, for $2 billion you can probably buy back at least four times as much water.
It would be easier for everyone if we did not have to change the way we use the Murray-Darling Basin. Change is never easy. But the quick fix of “new water” appears to be an illusion. We have no realistic choice other than to make better use of what water there is, and any amount of noise from water users across the Basin isn’t going to change this inconvenient truth. I just hope Tony Windsor is smart enough to see that.
As some of you are probably aware I am a Murray irrigator [sort of, technically you need to have your pump foot valve in water and although 'my' lagoon has come back its not that deep yet, if ever].
My current allocation of cost free water [nix/nought/zero/nil cost to me, well a bit of tax deductible electricity] is 135 million litres of water for this year.
You city folk may wish to ponder the economics of that.
If you want a spin free analysis of some options of how to solve the problem of the MDB check out the Wentworth Group of Scientists who analyse the options here:
http://www.wentworthgroup.org/uploads/Sustainable%20Diversions%20in%20the%20Murray-Darling%20Basin.pdf
It takes too long for my rural computer service to access the text but broadly it looks at ways that water can be returned to the river, irrigators can be given lots of money, communities can be protected from dire impact, and Aussies won’t starve or pay millions of $$$ for an orange and so on.
It opts for one method which will achieve all of the above pretty darn easily quickly and simply.
So, of course, that won’t happen.
I have a solution to this problem that should satisfy all parties.
More rain.
Sam
The prognosis for future rain in the Southern MDB in coming decades is a 20-30% reduction compared to historical falls.
In other words expect less rain in the future cf the past, more droughts, more severe in nature, less floods with less volume, average of all such at a lower level than the past 20-30 years.
The problem is human and the climate is merely exacerbating the underlying fundamental cause namely overallocation of water for irrigation.
Here check this out.
http://www.theage.com.au/national/its-not-drought-its-climate-change-say-scientists-20090829-f3cd.html
Robert,
Regarding diverting the Northern Rivers to the Murray Darling, wWhy not take Mohammed to the mountain instead ?
HD, maybe you’re right. On the other hand, in the article you linked to
Time will tell.
Queensland has a few gazillion litres of interesting water, looking for a beneficial use. Might be a temporary and somewhat risky solution though.
Is this “interesting” water “heavy water”?
But “new water” in the MD?
This sounds like “wealth creation”, except that its based on “water creation”?
Heaven’s, fusion, something from nothing etc, etc- my head starts to spin..
More seriously, Windsor sounds conservative here, but when you think how insensitively other “reforms” have been implemented over time, you suspect that he wants some thought put into that aspect, this time.
Sam,
Yeah Freeman’s credibility is not high [wink].
Also check out the CSIRO MDB Sustainability Report, the largest of its kind ever in the world apparently, [googling that should get you the report] look at the executive summary and that’s were I got the 20-30% numbers from among other nast bits of info.
There is no shortage of data saying future rainfall in the SMDB will be less than the past, ask Brian nicely and he may direct us to CSIRO or BOM maps that show the past decrease.
I’ve tried 4 times to post some links here. The MDB Sustainability report being one, but gremlins are at work and I suspect trying to link to:
“The Wentworth Group of Concerned Scientists”
Go to “Recent Reports”
Second of such is an analysis of options that could solve the problems of the Murray.
Simple stuff.
Essential reading.
[Your comments went into the spam bin - don't try to re-post them as this can make the problem worse
-AW.]
That declining rainfall and a hotter climate are tied to native forest vegetation and its wholesale removal was something explicitly argued in scientific circles by W.B. Clarke, the “Father of Australian Geology”, as early as 1835.
We’ve slashed the bush now we pay the price.
Thanks for that info AW, can you tell me why that happened so I can avoid it happening in the future?
Great work in pointing to these credible reports and analyses. Wouldn’t it be fabulous if we lived in the kind of world where they would be made required reading for all the media and other commentators (well sometimes I think those kind of authoritarian things). Seriously in the next short while the hysteria around the issue will be first cab off the rank in all the consultation meetings.
This issue could be a case study on the inadequacy of the media in this country. With the notable exception of Ross Gittings, mostly all the media and in particulary the ABC, can be bothered to do is stoke the hysteria and report in the most pathetically tabloid way.
If we can’t rely on the public broadcaster to provide some reasoned analysis of the actual issues and the reasons for the report, what is its bloody point?
My solution is to use one of these to lift some of this to the Murray-Darling.
Surely a cheap and cost effective method!
Adrian @ 12 I recommend a listen to ABC Bush Telegraph for today with compere, Michael Cathcart and irrigation expert, Prof Wayne Meyer. I recall Meyer, then at CSU at a meeting of Murrumbidgee rice growers in the early 1990′s warning of the problems stemming from over allocation (120% plus)and copping an angry reaction still evident in public meetings this week. Cathcart is also a thoughtful writer on the problem.
And best not to look at the transcript of this mornings A.M.,pablo, where reporters Cave and Herbert seemed to be doing all their best to fire matters up…..
http://www.abc.net.au/am/content/2010/s3037927.htm
Henry had plenty to say on cross-subsidies that would need to be addressed before it came to this. The irrigators are right, given recent history, to assume that a sudden hot blast will frighten pollies into reversing any action and showering them in cash to allay any hard feelings.
Granted Joe2, the public meetings will generate a lot of heat and light and are already determining the political response with Gillard’s formation of a committee.
Some are already suggesting this will usurp the MDBA program. But it’s a tough call expecting ABC roundspeople to somehow not reflect the anger and aggravate it further as your transcript shows. Expect even more aggro from both sides at Dubbo and Moree. Maybe if the MDBA had released the draft before the Federal election, as originally planned, the heat and light would have been more nationally felt.
Yep, the proposal to divert water from coastal rivers in northern NSW – for instance, the Clarence River was opposed AND will be opposed again and again and again and … … …
Anyone who thinks it’s environmentally ok to drain an eastern flowing river, such as the Clarence, and send its waters west obviously has their brains in their b8m. It’s ecologically unsound. What such a person is really saying is, “OK, we’ve st8ffed up this catchment’s ecosystem, but there are others that we can st8ff up too”.
pablo, Abbott would have had a field day manipulating it’s contents if it had been released earlier.
Todays effort, by Aunty, in running reports all day about possible bank foreclosures, while now totally denied by the banking industry, has been particularly unhelpful and provocative.
Abbott and co have every intention of playing political with this, like everything else, and their ABC, apart from a few notable exceptions like Michael Cathcart are relishing the biffo.
At the moment they are running with “A crisis of cowardice”. Apparently, quotes from opposition spokespeople are always worthy of direct headline transcription.
I find it hard to take environmental plans seriously when they want to divert agriculture water to keeping very large lakes as fresh water lakes when they used to be tidal lakes. Converting them back to their natural state would have the added advantage of increasing tidal flows through the mouth of the Murray and thus helping to keep it open.
Given that we are talking about water shortages reducing the capacity of the the basin to produce food it is worth asking whether it really makes sense to be sending water down the Darling to SA given claims that only about 20% of it reaches SA.
Similar questions should be asked about maximizing the amount of water that actually reaches plants. Location of farms, use of drip systems etc. Tony Windsor seemed confident on the 7.30 report tonight that real savings could be made in places like the Menindee lakes.
Am I the only one getting tired of country people whining about any change at all?
When the industries in New Castle and Wollongong shut down, entire communities were ravaged by gigantic job losses and social dislocation.
I didn’t see them demanding billions of continued subsidies to preserve their present unsustainable (economic in this case) way of life. I lived through that period. I never saw the level of whining and self-pity I see from country people today.
Here’s the Bush Telegraph piece.
John D, perhaps you heard Jennifer Marohasy on Counterpoint talking about her Quadrant article. She contends that the lower lakes should be returned to being tidal, as they were before the barrages turned them into freshwater lakes.
“water is heavy. Pumping gigalitres of the stuff across the Great Dividing Range is going to require a great deal of very expensive infrastructure and a lot of energy.”
Nah, it’s easy. Mr Brumby just spent $700 million on a pipeline to take water across the Divide in Victoria. Of course, the pipe takes the water OUT of the Murray …
I love the idea that we can “tolerate” certain environmental constraints and others cannot be “tolerated”.
So, the best option, according to the irrigators, is just to let the rivers die? So, tell me, what woukd happen to the river towns then? So far, it seems to be primitives 1, rivers 0.
Philomena@ 9 “We’ve slashed the bush now we pay the price.”
Peter Andrews wrote about this in one of his books. He claims that re vegetating dry, marginal inland areas would increase rainfall.
Pretty sure he recommends 30% re vegetation of large marginal cropping/grazing properties to achieve the “rain making” benefits. (don’t quote me on this, its been a while since i read it)
ALTRIG (Australian Low Rainfall Tree Improvement Group) forestry species could make this profitable, as could wider adoption of dry land fodder tree systems.
https://rirdc.infoservices.com.au/items/09-078
As usual, Bolt’s in there with his confected outrage, calling the plan a “jihad against our farmers”
‘Farmers have driven their tractors in convoy to South Australia’s first community consultation meeting on the Murray-Darling Basin plan.
The drive at Renmark, 250 kilometres from Adelaide, was in protest against proposed massive cuts to water use by irrigators.’
The Kulaks are revolting.
This website has been collecting information for years now on why the Lower Lakes should be returned to estuaries. There are links to some interesting reports. http://www.LakesNeedWater.org
I agree with John D, it is hard to take an environmental plan seriously when it did not even make one mention of the barrages, especially when one of the goals is to keep the Murray Mouth open.
That paper is fascinating, hannah’s dad @ 1.
Brian @ 21, much as it pains me to concede it, Our Jennifer is probably partly correct about the lower lakes’ salinity. What she conveniently ignores, of course, is that the lakes would have only been brackish some of the time, mostly near the mouth, and that they would’ve got flushed out each year.
how very clever to call irrigators primitive, how surprising that there is animosity between parties!
Why do you think the rivers sustaining irrigators are about to die? There are a lot of these claims by people least likely to have visited an irrigation area, or even taken the time to realise that the water is still within the environment but in different circumstances.
We know significant droughts have occured in the past.We know the lower lakes weren’t always fresh, and more importantly we have experienced record low inflows in the MDB over an unprecedented period of years, ensuring that the lakes would be a lot saltier than they are today.
Surely you can understand farmer surprise at the authorities claim that 4000GL is a compromise, when only a few years ago 1500GL was the upperband requirement to “save the Murray”.
It can be hard for urban populations, many who rarely meet their neighbours, to understand a tightknit community where work collegues are on the same school P+C committee, stand together at saturday morning sports or rally to help a community member in need.
You’ll have to forgive us for not wishing to farewell friends, and in cases family.
The display on the box of these whiners was pathetic.
The problem is the government then announces a response and probably will result in more money. This is enabling.
I can imagine it was started with Macquarie bitching and moaning early on in the colony years and successive farmers/squatters have seen the rewards that result making them, what, 5th generation whingers.
Voluntary buyback – remove both voluntary and buyback to at least give them something to whinge about.
**Maquarie=Macarthur
ooops – sorry
John D – “I find it hard to take environmental plans seriously when they want to divert agriculture water to keeping very large lakes as fresh water lakes when they used to be tidal lakes. ”
Are you suggesting that freshwater flows aren’t important in the Lower Lakes and the Coorong?
“Are you suggesting that freshwater flows aren’t important in the Lower Lakes and the Coorong?”
I imagine these concerns are of little import to eastern states irrigators, and other assorted boosters FB.
In the recent drought irrigators received far less water than their nominal allocation. This seemed to me to be a far more sensible approach than using buybacks to reduce our ability to take advantage of runs of wet years. The help we really need to help farmers and their communities is in reducing water losses, moving to crops that give a better return per litre and the development of plant varieties that use water more effectively.
What the irrigators need to talk about now is how allocations will be ramped down during the next big drought. It might focus their minds on what is achievable and how they shoudl respond when their water allocation is low.
There is no obvious reason why “environmental flows” can’t be part of the allocation system. However, some hard questions need to be asked about the nature of the flows required and the benefits that would result.
Perhaps we should be asking questions like “what would we do if the environmental flow was limited to an average of 1000 glitres/yr?” Questions like this may focus some minds on what really needs to be sustained, what will bounce back when the rains come again and what we may have to say good by to.
Paul @22,
spot on. Hope the ALP finally show some spine on this issue.
John D, most general security licences in NSW yielded 0% allocation in the last 2 years, and in my case 4 of the last 5. Further ramp downs might be difficult.
Duncan and furious, the lakes have always had to face drought and while they have been freshwater 95% of the time, 5% of the time they weren’t. 1 in 20.
In the last 70 odd years the lakes have had no ingress of sea water thanks to the barrges.
Obviously the lakes survived those periods of salt water, so rather than suggesting freshwater is not important for the lakes it’s more long the lines of: do the lakes need to be freshwater and held to a level 80cm above sealevel 100% of the time? If nature is a guide – No.
We’re defying nature, and plan to use stored water to defy nature further. In an attempt to mimic nature, but only in desirable ways.
The folly of the whole plan is that the barrages were built in the late 30′s early 40′s to stop sea water intrusion. At a time when according to the basin plan total extractions would not have exceeded 4000GL. Of course stage two of the plan may be to remove the barrages, in which case hypocracy won’t be an issue.
It’s not that Eastern state irrigators don’t care, it’s that they can do nothing about lack of inflow to the system. Record low inflows that without the aide of storage releases and river locks would surely have seen the Murray run dry altogether. Naturally.
.
rojo, I simply asked a question of John D, so I’m not sure why you are addressing me as if you already know my own position on the matter. I was merely a tad incredulous that John D could make such a statement about a complex, and yes, highly modified ecosystem, whilst suggesting he couldn’t “take environmental plans seriously” if they aim to maintain “freshwater lakes”.
He ignored my question in regards to the importance of freshwater flows into the system. He seems to be suggesting that the Coorong and Lower Lakes are something we need to say goodbye to. But lets not be parochial about it, the eastern states have plenty of goodbyes to make too.
rojo, the system is over-allocated. You can talk about lack of “inflows” ’til the cows come home, it doesn’t change that fact that even in a good year the river is over-allocated. And yes, barrages, locks and weirs are artificially keeping the system limping along, unsustainably, which is kind of what I was getting at with my question to John, who seems to be suggesting that the plan is simply about maintaining an artificial freshwater lake at the bottom of the system.
FB @33: I am suggesting that the lower lakes would have fluccuated between fresh during floods and seawater salt level in the past. The ecology of the lakes would probably have been dominated by species that could handle estuarine environments or move in or out of the lakes as the salinity changed.
The Coorong is different in the sense that there is very little inflow apart from what comes from tidal action near the mouth. While salinity near the SE end of the Coorong will be much higher than the salinity of seawater I would expect the salinity at a particular point along the Coorong to changes depending on the salinity near the mouth of the river. So, like the lakes, the ecology of the lakes would probably have been dominated by species that could handle estuarine environments or move in or out of the lakes as the salinity changed. The location of species might change but the spread of species in the Coorong would probably remain much the same no matter what the salinity at the mouth of the Murray was. So here too the environmental case for sending fresh water to the mouth is debatable. As I said before, conditions in the Coorong may actually benefit from the increased tidal flows at the Murray mouth that would be a consequence of returning the lower Murray lakes to their former estuarine condition.
The draft report mentions that there were over 2000 locations in the basin of environmental interest. Hence my question re what effect various environmental flow levels would have.
furious, I wasn’t too bothered what your position was, I was inputing my thoughts and stance on the situation. I merely took it that you had no idea.
I’ve reread my post and can’t see where I made any assumption as to your stance, not to mention that the answer was to both furious and Duncan.
Well that’s progress, now it’s about “2000 locations of environmental interest”, not just the artificial freshwater lower lakes?
I think the hard questions have been asked already, John D, this plan is an attempt at some answers, earlier you seemed inclined to dismiss that attempt based on a false premise. Perhaps I’m misinterpreting your comments but I’m kind of staggered that you come out swinging with a comment about not being able to take the report seriously and then make further comments suggesting that the impacts of greatly reduced flows on the environment [and the communities that depend on those environments] haven’t already been considered….?
John D @ 35 – didn’t the report say the environment really needs 7000 GL/year but that they are proposing only 3000 GL/year? That sounds like they have already made some hard decisions about some parts of the environment that are going to be sacrificed because water has been so over allocated in the past.
Chris, the guide suggests:
“To meet this range would require an additional volume of between 3,000 GL/y and 7,600 GL/y (long-term average) from the current diversion limits.”
I went to my Mums to catch up with my aunt and uncle who were visiting from the country earlier in the week and something about the report came up and they started to rant about it…and I said I couldn’t really comment because all I’d seen in the news was the reactions to the report, rather than any real info on the recommendations etc, they conceded that they had no idea what the report actually said either. Again, we are being failed by the what passes for journalism.
Today is the first chance I’ve had to read [part of] it, I hope i get some more time on the weekend to have a proper read.
I don’t suppose you or your family had every considered reading the report for yourselves
ha! I don’t suppose you considered reading the rest of my post? Regardless, it’s a strange thing to say right after I quoted directly from the report. As for my aunt and uncle, they were in the city for doctors appointment, my uncle has terminal cancer and my aunt has a heart condition, so I don’t think they really had time to download and read the report.
Are you sggesting it’s unreasonable to expect some more thorough reporting of a long awaited report, rather than just the daily outrage of the rural meetings?
@46,
Sorry furious balancing, it was very careless of me to miss the last sentence of your previous comment. A risk of commenting early in the morning. My apologies.
But my wider point stands. Why are we complaining about the media failure to spoon-feed us (and it seems to be a common complaint on this blog), when the internet now makes its straightforward to go straight to the source?
On the other hand, I agree that the media delights in beating up the issue and, in so doing, may have unecessarily exacerbated your family’s – and other stakeholder’s – concerns.
Furious B@42: It is worth reading in fullthis article by biologist Dr Jennifer Marohasy on the lower Murray referred to by Brian @32. Near the end she says:
It is clear that maintaining the lower Murray lakes in their unnatural condition is going to require over 1000 gigalitres of water a year. If this comes from Queensland, about 80% of the water will be lost on the way. So somehow you are expecting Barnaby Joyce to go all quiet about 5000 gigalitres of irrigation water being taken away from the area where he lives to support environmental vandalism by SA?
No worries, I & E. My uncle can’t actually read or write so he, and I suspect many more of his generation than we realise, are particularly at the mercy of second hand info. Btw, his industrial deafness also made me realise I should stop moaning about some of the more bizarre OHS stuff I have to deal with, but that’s another story.
I agree the quality of reporting is something that is bemoaned a lot around here, bit generally along party political lines, particularly in regards to election coverage. For me the report into the plan particularly highlighted the problem. I rarely buy newspapers but I did pick up a copy of the Stock Journal, as well as the Friday Fin Review to see if there was any more food for thought, given the target audiences of those two papers. The Stock Journal, had the (slightly) less inflammatory coverage including this quote, from an article titled ‘no fat left to cut’: SA irigators – “Since SA capped its water usage 40 years ago, our irrigators have foregone expansion. We only expanded within our means by putting in infrastructure such as pressure pipes and drip irrigation that has created efficiencies, while more than 3000 extra gigalitres has been taken from the system in other regions”.
@48,
Yes, we seem to have the classic moral hazard problem that irrigators who have been prudent and efficient are treated no differently to those that have been imprudent and inefficient. We had the same problem in the CPRS with brown coal generators.
On the other hand, if SA irrigators are more efficient, they should value their water more highly. This should mean that the buy back price is higher in SA. So, perhaps SA irrigators will see a suitable return on their investment.
I don’t know if the way that the proposed cuts have been distributed across the MDB is purely for technical/environmental reasons, or is also to “share the pain” socially and politically. If the latter, the SA irrigators do seem to have some reason to feel aggrieved.
These are complex issues, and journalists do not seem to have the time, inclination or incentive to delve into them.
The big in efficiencies with SA irrigators are the losses involved in getting the water to SA irrigators in the first, particularly the irrigators that depend on the water in the lower Murray evaporation lakes.
The good rains we are receiving this year give us time to identify opportunities that will allow us to keep irrigators in business by overall system efficiencies, irrigation efficiencies and changes in crop mix and the way droughts are managed.
John D @ 51 – I wonder if there is a way to take into account the evaporation when doing water buybacks. For example if they need a certain environment water flow at the murray mouth, then buying it way upstream would only result in X% of the allocation being counted as some of it would evaporate. This would effectively increase the price the government would have to pay for the water compared to buying a water allocation near the river mouth. But if they need an environmental flow further upstream then there would be less evaporation discount factored in and it would not be valid to buy water at any point downstream for where it is actually required.
rojo said:
Without the locks the Murray would run almost dry a lot more often – and allocations upstream would be forced to be a lot lower as there’d simply be little to no river to take water from. So I don’t think people can complain just about barrages near the end without taking into account that there is a lot of other artificial manipulation of the river to make irrigation possible in the first place. Its not like we need the river as a transport route anymore.
Agree Chris. We need to include evaporation and seepage losses associated with moving water from A to B under different flow conditions. We also need to include losses from various storage systems when deciding how water from these systems should be used. For example, it may make sense to use water held in Cubby Station style shallow storage before using water stored in deeper dams.
Perhaps one of the things we should ask is what we would do if we were starting from scratch? It might focus our minds on the direction we should be trying to move now.
John D – just one thought regarding evaporation. I’m not sure its a simple equation of X% of water evaporates from a given point to the murray mouth. As you sort of imply in your previous comment – wouldn’t the amount of water evaporating be dependent on the surface area of water exposed. So if adding a certain amount of water to the river doesn’t significantly change the width of the river (may change the depth) then you can get nearly all the *additional* water that has been purchased reach the end.
Chris: It depends on the shape of the channel, turbulence at the water surface and water temperature. But yes, I would expect the percent losses to drop as a percent of flow for deep channels with steep walls.
The evaporation issue is particularly important when considering the wisdom of stopping the lower Murray lakes being used to transfer water to a very limited number of irrigators. It is also important when considering stopping flow in parts of the Darling and/or transferring water in slugs rather than steady flow.