Joe, up until now I've assumed that you know as well as Tim Flannery does that the desalination plants were built to give us a reliable supply of water that will not be vulnerable to droughts.

Was my assumption wrong?

If and when supply of agricultural products becomes the limiting factor, we should all be prepared to pay higher prices for them. But the demand isn't there yet. There's not much point building expensive infrastructure just to grow unprofitable food.

There's surprisingly little difference between the cost of building and operating a desalination plant and a new reservoir with water treatment plant. But cheaper untreated river water is suitable for most irrigation applications.

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Rhosty, AIUI solar desalination can be viable for growing crops in greenhouses, but is not viable for irrigation of broadacre farmland. I expect it will be eventually, but I don't think we're at that stage yet. If you have information to the contrary you're welcome to post it, but I suspect you're again confusing what's being promised (like your "cheaper than coal" thorium power) and what's actually being delivered.

The Great Artesian Basin is actually a system of three linked artesian basins, each with immense variations in pressure between different parts. We should do a lot more to recharge it in flood years. But it is not suitable for transporting water from northern Australia to southern Australia.

Frost isn't a big problem in most of Australia. But where frost occurs, you can't adequately protect the leaves of vulnerable plants simply by warming the ground, though turning on misting sprinklers is likely to give good protection.

Hi Aidan,

They are already built, and standing idle. My point was that, since they are there, and costing every day, why not turn them back on, fill up the dams, and pump the rest back upstream for more irrigated farming ? Easy-peasy !

See ? A fool can ask questions that .......

Joe