The Filling of Lake Eyre.

The time has come, the pundits cried,
To speak of many things,
Of ozone layers and climate change,
And whether man can win.

Explorers sought an inland sea,
But went in the wrong year.
The sea is there, it’s normally salt,
We named it after Eyre.

But when the rains cross Darwin’s hills
And wet the inland ground,
The pelicans and cormorants know
Good times have come around.

We’ve rain aplenty every year,
In Queensland and the Gulf.
It runs the wrong way, out to sea,
It’s time to cry “Enough!”

Lets turn the water round, my friends,
And send it to the south.
Turn the land from brown to green,
At least more than its now.

The land is dry, the land is flat,
The way is very low.
Once it’s up, it’s all downhill,
Just let that water flow.

They did it with the Snowy,
It was a mighty task.
The Murray-Darling basin
Grows all the food we ask.

More water for the inland,
To grow tree, crop and plant.
But also to evaporate,
And fall as rain again.

Roper, Towns, Cox, Rosie,
They all go to the sea.
The Leichhardt and the Flinders,
Which one should it be?

The time has come, or so say I,
To speak of many things,
Of drought’s dry grip and climate change,
And filling up Lake Eyre.

A nice, poetic message there, Cliff.

Your idea of diverting the rivers inland (an idea that has been around for quite some time) would be good for growing crops in the desert, which in itself would help the local climate somewhat. However, I don't think it can be used to permanently fill Lake Eyre because of the large area, and very high rate of evaporation. I remember reading somewhere that even if the entire flow of the Murray were to flow into Lake Eyre, it would only just be enough to keep up with evaporation.

There are problems with this plan. Firstly, how do you regulate the level of the lake? It would vary according to rainfall, since the only outlet is evaporation. Also, if the lake gets priority over irrigators, there may not be much if any water available for irrigation. If irrigators are considered more important, the lake will probably remain dry.

My proposal is to dig a sea-level canal, about 500 metres wide and about 20 metres deep, from the head of the Spencer Gulf to Lake Eyre South, via Lake Torrens. This would have the side-effect of permanently draining Lake Torrens, though it's no great loss since it fills more rarely than Lake Eyre. The sea level canal would be free-flowing, and the water level in the lake would stabilise at sea level or only slightly lower. Water would flow through Lake Eyre South into Lake Eyre North. To regulate the salinity, a pipeline (or multiple parallel pipelines) will extract water from the Belt Bay area and dump it in the Great Australian Bight, somewhere between Streaky Bay and Ceduna.

This is the best solution, in my opinion, because it only uses sea water, which is free and inexhaustible. There's no point using freshwater of any origin for this project. If fresh water were available in sufficient quantities, we would sooner put it to use in irrigating the desert to grow crops, which would have almost equal evaporation benefits while being much more economically productive.

Some times something sounds as Usual utopia of mates privileged to have a paid job in Australia: evaporation, erosion/salinization and power consumption will out-weight water supply benefits.

I like your thinking, geek100, but there is one small teaser in the logic. The canal would not be dug 20m down, but to 20m below sea level. I don't have detailed information, but I did think that it would be at least a couple of hundred meters deep in parts. A search suggests that it might not be so deep, but even Lake Torrens is 34m above sea level according to one reference:

http://www.atlas.sa.gov.au/go/mapviewer?envelope=431383%2C1666822%2C1221509%2C2078129&appdatatopic=Physical+Geography&launchmap=Launch+Map

On the positive side, you could get more fall by using a sea wall to hold the high tide height.

If the excess salt is to be piped out, it would need to be concentrated. This could be done with a desalination plant, producing fresh water and brine.

How about using pipes to get sea water in? One suggestion is a tunnel, no uphill pumping.

Fresh water from the Gulf would not need to keep Lake Eyre full all the time. It need only extend the time it is full a bit to be useful. So a (relatively) small trial could see what benefit there is. Also, it need not be either/or. Sending water inland from the Gulf, the eastern Queensland coast or the southern ocean can all be beneficial.

I think it would be preferable to keep the lake full all the time. It would give a more consistent climate effect.

Using a tunnel to get water in would require a pretty big tunnel if it is to be gravity-fed. Pumping water in may involve lower initial costs, but higher ongoing costs. A lot of water has to be moved.

As for concentrating the outgoing brine, I was thinking of just letting the lake do it. If the pipe removes water at one third the rate of evaporation, the salt concentration in the lake would average 4 times the salt concentration of Spencer Gulf, which itself would then have reduced salt concentration because of the continual flow-through of water. I guess you could have less pipe if the salt is concentrated, but the energy cost of concentrating it is probably less than the cost of pumping it all the way to the Bight.

So, after practising perfect native English, what all this fuss of a lake was about at the VERY end but a DISCUSSION?