It would nice if there was just one independent scientific report by estuarine scientists that did model how much water is required to operate the Lower Lakes as the very large estuary they once were.

It was quite common for Lake Alexandrina to 'go salty' during times of low river, and not until farming was encouraged around the Lakes did this become a problem. You will notice that many of the comments of the Lakes going salty back in the early 1900's are from the newly established dairy farmers at Narrung and Lake Albert.

In 1844 the Lakes were mapped and areas of fresh, brackish and salty have been clearly marked by the South Australian Company. This is long before there were any significant diversions.

Susan, I disagree with you entirely. The purported problems of the Murray Estuary are short-term and short sighted, derivative and symptomatic rather than substantive. They are not even historically significant.

To resolve them the tributaries and upper catchment must be sorted out first, as suggested, progressively and in carefully thought-out stages, then their effects monitored in the upper mid-catchment, and fine-tuned on that basis. It follows that once the remedial effects flow-on (pun intended) down the river system, the estuary will sort itself out.

There is no point in demanding a greater 'share' of water from higher up in the catchment, where that leaves the upper catchment short. I'd call that a form of cutting off your nose to spite your face.

The Murray Darling system is somewhat unique in Australia in that like very large river systems overseas it depends on upper-catchment precipiation and snowmelt in this case to the east, feeding a system of streams that flow away toward the southwest and west.

Here in Western Australia monsoonal rain comes in from the west, by contrast, starts on the estuaries first then moves easterly up west-flowing catchments, so catchment ponding by building downstream dams over here to fill locally rather than from upstream has quite a different effect.

In the Murray-Darling system the estuary is the final port of call, not the first. Water lost from the upper catchment is water gained by the mid-catchment, and so on, assuming those points have the capacity to restrict the flow and retain water rather than simply allow it to flow through. Once the water has gone from the estuary, however, it has gone forever.

It follows that rapid loss of water in the upper catchment induces a generally drying ripple effect all the way downstream, to the detriment of the entire catchment.

Yes, I agree with John Troughton, it's child's play. Any primary school could have their pupils construct a generic scale-model catchment for themselves, and examine different precipitation regimes approaching from different directions.

I challenge you to do that yourself. Get your catchment management group to build one, you wouldn't even need funding just sand and plaster of paris, and some paint if you want to pretty it up, then put it in the back of the ute and cart it around to all your schools.

I sometimes think that all this is going on far too long because we are still engaging the children on it far too late. They're not kids for very long, it will be their job in short order, we can have them _knowing_ what to do as part of their primary and lower secondary school work, so the moment they come of age they'll just get straight on with the job . . . .

. . . . without us bogging them down in the endless bickering of our generation . . . . that would help an awful lot, quicker than you might imagine . . .

That is true David although there seems to be some sense in keeping the upstream ones in palce since as many point out, they allow for a regulated flow down the river to feed the areas as necessary. Otherwise, whenther is a big flood as for 2011, 2012 and other years, all of the water is soon lost down stream and out to sea.

Come a drought, and the same areas suffer. Of course, if one is trying to be totally natural, then yes, all structures should be removed for that to occur. I am not sure though that that would be the best for the river. For instance in the 1850s, the Darling river did `not run for three years in a row. The same happens to the Murrumbidgee biut the Murray of course is better served by rain and snow.

I still think a first sreop ought o be to remove the main Barrage, 7.6 km, which serves a very artificial purpose and requires regular flows to maintain a fresh water lake which is naturally estuarine and salty. This would not be maintained as a fresh water lake anyway, without the upper river dams to feed into it in dry times. John Nicol

No, Shane, I disagree with you as well.

It is not complicated. We have very finely detailed knowledge of the Murray-Darling system, living on it for over 200 years now.

The far bigger problem we face in addressing the issues is the flood of immigrants from Europe and all sorts of places over the past 50 years and more.

That is not a racist or nationalist remark, merely pragmatic recognition that all those people come here carrying knowledge and other cultural baggage from other landscapes entirely, and that there is a delay while they become acclimatised and familiar enough with these landscapes to see that like home, here is not complicated either, it merely requires a cognitive shift to be able to see.

That is a large part of the current problem Australia faces with all those people now perched precariously on the rim of the continent, fearful I guess of dipping even their big toe into the pond, where when I was a kid nearly 60% of Australians were country dwellers, partly understandably as one of the outcomes of the Great Depression, where at least they had food and shelter.

That we have achieved so much since then is to our credit, of relevance here placing the Murray-Darling system back into its proper perspective.

I repeat. It's not hard. We know the intricasies of the system like the back of our hand. There is no singular linearity to be traversed, but manifold histories and ethnicities well beyond the stock indigeneity being wheeled out at every chance there is. There is no 'one nation' but many and various, with finely detailed knowledge and methods.

The problem we all have in common is trying to wade through the endless gobbledegook and hot air generated by those who haven't the slightest clue what they are talking about, but somehow or other find a hearing for some reason.

I guess its the way television works, with its SitComs . . . . and as you point out media cartoons in place of core facts and informed debate.

It is a telling indictment that people working in these fields do not know each other and the work they've been doing all these years. That's a large part of my complaint, that so many different people are doing the same work over and over again, fragmented I argue through capricious funding cuts and constant challenge to our integrity ad absurdem.

Yes, we understand uncertainty. It has been applied here ad nauseam, until as I have suggested elsewhere if it were applied to itself it would disappear up its own arsehole. Good, that's where it belongs.

At best you'd be teaching Year 8 and 9 students that there is no such thing as complete and absolute knowledge, that it impossible to know everything, that we always only ever have partial knowledge, always something new to learn, but that can never be held up as pretext for stopping funding on such important projects, and diverting public money into areas where uncertainty is never an issue because all anyone has to do is be 'creative'.

Yes? Uncertainty is not a fatal disease, its merely a fact of life. Yes, we accept that some projects may not turn out as planned, that's given. It's not an issue. It's the reason we carry out constant monitoring, the reason we spent so much time developing key indicators and applied them. We even marched acacias down into salt pans to see how far in they'd survive, then used that data in species selection for broader application. That work was done over 20 years ago.

OK, next, when I speak of 'fine scaled', or course I don't mean to count the fleas on a dog's back, or the mites on the fleas. Get the scale sorted. The Darling River is over 900 miles long, nearly 1500 Km. Even on that scale, a colleague of mine wrote his PhD thesis on dragonflies in a single reedbed, and that was 25 years ago.

So, if you've been there and done it, why the 'uncertainty', the doubt? Maybe that's part of the problem, despite their field experience everyone's still been brainwashed into thinking its all too hard, too uncertain.

What do I say to that? Calling in sociology here, perhaps Frank Ferudi's observations on the prevailing culture of fear apply, subtitled, risk-taking and the morality of low expectation. Maybe buy the book and have a good read.

If you don't want to work with me, don't. I'm over here in WA right now, we're looking at young leaders happy to ignore the nay-sayers and simply get on with the job. Except of course, while we get rain every year there's no soil, so the issues are far more urgent.

And by the same token, you might have introduced yourself first. I don't even know who 'Paul' is. This is till the Internet, it's still text based, maybe if you want a conversation start with a conversation.

What you started with is drivel. I'd disagree with you all over again.

OK, yes, while I'm thinking about it, if we are to have a conversation let's have a conversation.

The context to me suggests intelligent, well-informed conversation not bullshit over a few beers at the pub, a bit of six o'clock or even ten o'clock swill before he have to be out of there, no worries mate, she'll be right.

Yes, I understand The Conversation is new, but Netiquette has been around for 20 years, as much to do with context and appropriateness of setting as interpersonal regard.

There is no point in even hosting the thing if resulting conversation can't even match a an undergraduate post-tutorial get-together, but descends to the level of Facebook.

What next, are you going to announce here that you brushed your teeth this morning, that your doggie pooed on the carpet?

I log on here in response to articles written by experts in their field, and seek to discuss the matters they've raised accordingly, not journos or media people looking for a cheap bite.

For many of the issues raised here, I argue that for any resolution to come about there needs to be a fundamental cultural shift.

It's not about lecturing, that's me, I'm an increasingly grumpy old fart. It's about raising expectations not dashing them with the unrelenting bullshit Australians have been fed for far too long now.

The Murray-Darling is not a big problem, it's not hard. What is hard, and you will agree that here is direct evidence, sustained and replicable field data, that the difficulty we face is not 'uncertainty' but all the bullshit we have to wade through just to get at it.

It's like a stalled tractor, easy to get the engine started. What's hard is getting it out of the bog.

Like everything in this stupid country. Nowhere else on earth, except maybe the USSR under Stalin, or Germany under Hitler, would allow science and scholarship and years of solid field research to be so compromised by such philistine ignorance.

Right, there's my rant. I'm disgusted by the unrelenting drivel we are obliged to suffer here.

I am VERY disappointed by it.