Yesterday a Murrumbidgee food producer, Virginia Tropeano, had a letter printed in the local Murrumbidgee ‘Area News’ explaining that in an average rainfall year it take 5,000 gigalitres of water to keep the Lower Lakes artificially fresh.
Because of the sea dykes across the bottom of the Lower Lakes, they are totally dependent on water from upstream. In drought years this makes the Lower Lakes completely dependent on water in upstream storages. The only really large and reliable storages in drought years are in the upper Murray and Murrumbidgee catchments because they are the only snow fed catchments.
The Premier of South Australia, Jay Weatherill, wants 4,000 gigalitres more freshwater each year for South Australia as guaranteed supply. Because the Lower Lakes are Ramsar listed and because of the way the Water Act has been written, he is likely to get this water even if he has to take the Murray Darling Basin Authority to the High Court.
I think that in a good year, the most water that is ever allocated for food production in the Murrumbidgee is 2,500 gigalitres. Can someone verify this figure for me? Assuming I'm about right, Mr Weatherill wants all of this water and more.
If you have continued to read this far, and you are not an irrigator, you are probably getting bored with my use of these meaningless figures of thousands of gigalitres. So help me make this a more interesting story.
How much food can 2,500 gigalitres produce?
Farmers in the Murrumbidgee use about this volume of water to produce food.
What types of foods do they produce and how could the total volume, or caloric equivalent, be described in a meaningful way.
For example, can someone let me know for how many weeks or months the population of Australia could survive on food produced from 2,500 gigalitres of water?
The Murray & Murrumbidgee do grow high protein bread wheats as well as biscuit wheats.
All varieties grow well here, so we can eat bread or cake 🙂
You are probably right Sean, reconfiguring the management there would support a further 200+ broad acre irrigaton farms when inflows are tight. That would be approx 80,000 tonnes of staple cereal crops.
How many extra mouths does that feed?
Also, as a bonus, the LRM and the lower lakes could be run as a functioning estuary & SA could use the unique advantave they have over the rest of the MDB.
Debbie,
I will try another approach.
By building Lock Zero and automating the Gates on the barrage we can reduce the Lakes pool level of 0.75 M AHD to achieve a fairly stable water level around 0.5 M AHD and operate the Mouth like a estuary. While out on my ride this evening along the river I caught up with my friend blind mullet and according to him the difference in GL’s between the old and the new pool levels is 694 GL. Debbie
if you have an allocation of 3200ML (3.2GL) to produce what you produce, then that 694GL can support around 217 farming properties.
"how do we make 2,500 Gl meaningful to the average Australian woman."
A loaf of bread for everyone on earth - although I really don't know how much wheat (guessing 500g) is used in a 700g loaf, ie. how much is wasted? .
Admittedly the Murray/Murrumbidgee regions may not produce high protein bread wheats, so let them eat cake.
I've just been sent an email explaining that of the 2,500 GL baseline allocation for the Murrumbidgee, only 400 GL of this is high security and so only 400 GL were available during the recent drought. So we can't reliably produce 12.5 tonnes or tones of oranges in the Murrumbidgee.
In particular:
"Rice, wheat, corn, oats, soya bean and several other cereal and oil crops like barley, canola, sunflower etc are grown by broad acre irrigation on General Security water entitlements and allocations. So are other fibre crops and livestock like cotton, hay, silage, wool (sheep) cattle (including a 50,000 head feedlot and abattoir), pigs, a large chicken enterprise (formerly known as barters) and other niche stock and fruit and veg like alpacas, onions, garlic, pumpkins, melons etc. These enterprises also underpin food/fibre manufacturing companies like Sunrice, Juice factories, Rockdale Beef, Riverina Stockfoods, Cotton Ginning, vegetable/fruit marketing and processing etc.....
Citrus, Grapes, olives, nuts, stone fruit etc are mostly on High Security entitlements in the Murrumbidgee Irrigation Area as they are permanent plantings.
It would not be possible to maintain 12Million tonnes of orange production because the water source is not reliable enough to do that. Only approx 400,000ML of the Murrumbidgee total entitlement is High Security. Oranges are permanent plantings and must have High Security water."
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I'm still receiving emails from people complaining that I have highjacked this thread. So, I have! And I reply, put some time into turning the comments I have been deleting into an interesting blog post and I shall post it as a new thread. Alternatively spend the time thinking about this question that I have posed: how do we make 2,500 Gl meaningful to the average Australian woman.
Sean,
I raise all sorts of issues at this blog that have nothing what so ever to do with the petition which respresents the combined efforts of the Myth and the Murray Group... not my opinion.
Now back to the topic of this thread... Your good at maths Sean and probably have a balance in your kitchen... how many oranges do you think are in 12.5 tonnes of citrus equivalent?
*****
More off topic posts will likely be deleted from this thread. But as I have indicated to Peter Smith in reply to his emails, if he send me something interesting I'm happy to post it as a new thread.
Jennifer,
Well why did you bring this up :-
I thought point two of the petition read :-
2. The estuary should be restored by re-engineering or removing the barrages in part or whole to allow inflows from the Southern Ocean.
Principal Petitioner
Kate Jennings
NOT
2. remove the 7.6 kms of concrete barrages, bring back the tide!
IF IT IS SHOULDN’T YOU CHANGE THE PETITION
Can we please get back on topic. As regular readers of this blog know, many threads wander, but every so often I would like some focus. I've asked for this above. Any more comments from Smith and others that are not focused on finding a way to explain how much 2,500 gigalitres represents will be deleted.
So with 2,500 Gl the Murrumbidgee could feed the entire Australian population for six months.