Saturday, October 16, 2010

Murray River - Not enough water.... or is that too much?

Is it just me, or does anyone else see the contradictions in the news articles in regards to the Murray River? If you google "Murray" in the news you get articles on the one hand about the grandiose plans to reduce water usage by reducing water allocations, and how State leaders and farmers are grandstanding about the disaster this would cause in communities where water buy backs take place.

On the other hand you get articles about this massive flood (the latest in a series of floods to hit the Murray-Darling System over the last year), how storages are starting to reach capacity and overflow and how even with high tech dam gates and good advance warning of floods, this still is a big potential headache and potential whole of system flood once they all actually fill.

18 comments:

Chris Fellows said...

What we need is a buyback, not of allocated water (which only helps the Murray-Darling in good years) but of on-farm storages (which would increase the amount of water flowing into the system in all years). I'm willing to start... when reader donations reach $250,000 send them to me and I'll bulldoze my dam :P

Marco said...

You have failed to capture the spirit of my post, I think. Bulldozing of on-farm storage makes the catchment more vulnerable to whole of system floods. What I'm getting at is the blindness to planning for floods which comes from years and years of drought and talk of it being a more common (than flood?) feature of the future.
I think the difference, if you take the threat of floods seriously as well, is that there will be less "high security" allocations (ie. ones where the government can't arbitrarily cut), more allocations that are almost infinitely high and cheap during floods, and almost nothing and/or hugely expensive during droughts.
Also, the allocation system can be tweaked such that orders can be made to "use it or lose it" at times where the risk of flood outweighs the risk of drought - ie. either draw down to less than 50% your dam or you will be ordered to release the water downstream (La Nina year for example)to allow capacity to absorb floods

Chris Fellows said...

No, losing on farm storage doesn't necessarily make the system more vulnerable, the water will just be in the rivers and the big storages instead, *but* the base level flow critical for environmental maintenance will be much better.

At the other end of the continuum, whole-of-system floods are also important environmentally: we shouldn't even try to stop them. We should just build our riverside communities in such a way that the damage is minimised.

Marco said...

What you are saying implies the environment doesn't really "own" the water or have rights to any water stored on behalf of it for the really really dry years, where flow would be releases of water held (wherever closest to the bit of environment we're talking about) in storages which would otherwise be a flow of nothing. I don't think the environment minds a moderation of droughts or floods, as long as the mean and standard deviation of water supply to that bit of environment is similar to what it would be in a wild river. In the case of the Murray, we will see that in a big flood there is enough water even for the environment's most lavish needs for floods. Drought time water needs can be controlled through water allocations purchases and release orders even more effectively than abandoning the whole basin to natural flows.

Chris Fellows said...

What you are saying implies the environment doesn't really "own" the water or have rights to any water stored on behalf of it for the really really dry years, where flow would be releases of water held (wherever closest to the bit of environment we're talking about) in storages which would otherwise be a flow of nothing.

In don't see how you could possibly think that was an implication of my comment.

Water can be stored on behalf of the environment at Copeton Dam, or any of the other large, formal, managed storages downstream: the river shouldn't be strangled at birth in my backyard. We store more water per capita than any other country in the world and a huge chunk of it is in these largely unregulated on-farm sites designed to ensure that what precipitates on the farm, evaporates on the farm. As long as we ignore this human impact on the 'inputs' fiddling around with the 'outputs' is never going to amount to a hill of beans.

Marco said...

I was under the impression that the water in these on-farm storages, where the on-farm storages relate to a catchment area, still has to be metered and paid for. I guess this may still be the exception rather than the rule.

Hmmm.. On farm storages, or artificial waterholes - only connected into a stream or river by large floods... Sounds just like the Coongie wetlands and the wild rivers of the Cooper basin!

I did, at one stage compare the efficiency of urban water tank storage over that of storing water in an average dam, and the dam is a lot more efficient and equitable - agreed. However - I would have thought forcing on-farm storage have the ability to syphon water to a natural stream which is "owed" that water in dry times is obviously going to be more equitable and flexible than tearing down the storage.

Chris Fellows said...

Nope, still no tax on rain from what I can see... just had a bit of a look around and found the rules in SA and WA which are more likely to be on the 'restrictive' side than not. You need permits to build or modify dams to trap runoff from your property them, but there is no charge for the water.

I would have thought forcing on-farm storage have the ability to syphon water to a natural stream which is "owed" that water in dry times is obviously going to be more equitable and flexible than tearing down the storage.

As they are constructed they aren't very useful in providing environmental flows: much better to have one person pressing a button at the dam closest to the headwaters rather than 1000 of us messing about with hoses... I am not of course suggesting a deep green program of savage compulsory acquisition, but a sensible buyback of superfluous structures, together with research to reduce evaporative loss from these things so they are more likely to be full and spill over. I suppose there are also engineering solutions you could bring into approvals for storages above a certain volume to make it easier to tie them into an 'environmental flow' system: then a grazier with a paddock that was not being used due to dry weather could empty a dam to provide a teensy environmental flow for a small cash reward.

Marco said...

Consider instead the benefits that on farm storage confers to the environment compared to a major storage. The local bird, waterfowl and wallaby population can come in for a drink when it's dry. Plants along the former waterway become more drought tolerant. After all a flow is just water moving from one useful place to another more or less useful place. A large water storage is less useful for certain species of flora and fauna. Large water storages are not necessarily well placed for managing the large number of small tributaries, which farm storages may be able to manage with good metering and tradeable water. I think the rivers themselves as well as various sections of the environment separately need purchasing power for a minimum flow when water is scarce, and the occasional flood flow when it is plentiful.

Chris Fellows said...

Consider instead the benefits that on farm storage confers to the environment compared to a major storage. The local bird, waterfowl and wallaby population can come in for a drink when it's dry. Plants along the former waterway become more drought tolerant. After all a flow is just water moving from one useful place to another more or less useful place. A large water storage is less useful for certain species of flora and fauna. Large water storages are not necessarily well placed for managing the large number of small tributaries, which farm storages may be able to manage with good metering and tradeable water.

Well yes, I agree with all those good things, but you can't have them AND Lake Alexandrina AND Deniliquin.

Land clearing leading to increase run-off means we should be able to have both irrigation and river flows not far from pre-1788 levels, but capturing all that increased run-off (and then some)means we can't. F'rinstance, see page 19 of this link.

Marco said...

Lake Alexandrina will be be full to beyond capacity by years end. It did not suffer a great deal of permanent environmental damage over the last 10 years of the Murray having been a closed system due to a very unusual sequence of years with a lack of major floods in the basin. And at any rate the lake is not a huge environmental area compared to the whole basin's environmental needs for water.
Although in that report you stated the on-farm dams in that area of WA represent most of the stored water there, the amount of water stored on farms in total appears to be little more than is stored behind river Murrays locks/weirs, and is completely dwarfed (by a couple of degrees of magnitude) by the larger water storages of say the menindee lakes, lake victoria, hume and dartmouth. These water storages were not even enough to get us through the decade, so I would suggest a couple more major dams in the Darling tributaries might be handy.
Should on farm storages be considered goods or infrastructure?

Chris Fellows said...

I don't think it is worthwhile making major investments to capture additional floodwaters in the Murray-Darling basin, especially if this involves messing around with relatively unspoiled Darling tributaries: we already store more water per capita than any other nation.

However, I think there would be wisdom in damming the river systems that flood Grafton, Kempsey, and other north coast NSW towns, more often than not: these would form deep Warragamba dam-like storages rather than shallow Lake Hume-like storages and so lose a lot less water to evaporation than any new dams on Darling tributaries, and would be much easier to pump over the Divide than the Snowy was. Of course, they are all in national parks atm...

My concern with farm dams and other earthworks designed to retain precipitation on farm is with the effect this has on the river system in bad years and what we can do to maintain roughly 'natural' environmental flows in these years.

Marco said...

The question of whether on-farm dams should be considered infrastructure of private property is not trivial. To deliver an adequate water supply to farms if their dam gets bulldozed may be cost prohibitive compared to considering the dam as infrastructure, upgrading it to enable remote control releases to the environment and reducing evaporation loss. A press of a button in a central location could then control large swathes of smaller tributaries. The water stored would not only enable farm use through dry periods, as they do now, but also environmental releases in the dry season. The farm dams would then be more able to be tools to include on farm water as a fungible asset rather than as a use-it-or-lose-it free resource.

Chris Fellows said...

In NSW, Phil McMurray, director of engineering services at the Gundagai Shire Council, told The Australian the Burrinjuck and Blowering dams had been kept too close to capacity before the deluge late last week that triggered the vast overflows.

Burrinjuck is on the Murrumbidgee River, which flows through Gundagai and Wagga Wagga.

"In hindsight, they should have been letting some water out over the past couple of weeks before the big rains," Mr McMurray said.

"Water is such a valuable commodity, they sell it to irrigators, so I guess it's in their interests not to let it out. But it would have been in the interests of the downstream communities if they did."


The Oz. December 6

Chris Fellows said...

Copeton Dam, on the other hand, was still nearly empty, so the torrents that came off the top of the ranges here on Wednesday-Thursday will cause no trouble to anyone.

Marco said...

Hey there - been meaning to post about this again.

I still think there is a great deal of irony with the Murray Darling Authority and irrigators crying poor over the dearth of water in the middle of a prolonged and system-wide refilling and flooding.

The prescient issue is how to manage floods. Dams have been very useful.

Chris Fellows said...

Hey, not at all relevant to this post, but I have just learned this morning that Julian Assange is from Townsville. In a sub-rational tribal way this makes me much more favourably disposed to the chap.

Marco said...

Wasn't it a "Light of Other Days" moment - when all this supposed secret stuff came out. It's all quite exciting.

Chris Fellows said...

Yes, I've been thinking about 'Light of Other Days' as well in this context. I am still not sure where I stand even to the extent of being able to write a sentence saying that I am still not sure where I stand.

I think it's great how so many of the pieces of evidence that have been released by someone with (as far as I can tell) a Chomskyite worldview are totally consistent with the Neoconservative narrative. I am waiting eagerly for the cables pointing a finger at [*Name Redacted*] for the Al-Mabhouh assassination!