A lot of the Roman Empire had their water delivered by aquaducts. Even the water for Rome itself (pop nearly 1m) got it's water from 100ks away.
If the Romans could supply water via aquaducts for a pop. of maybe 5m on a land mass as big as Australia. (Yes bigger and more populated later--I'm talking about the time of Christ). Surely with all our know-how and machinery we should be able to sufficiently provide Australia with all the agricultural water needed. We do get plenty of it up north. And they say, global warming will cause more tropical rain.
Now I just had a SILLY brain wave. Suppose all this water that falls up north, some can surely be delivered to the Darling basin, that shoudn't be too much of a problem. The silly part is this: other water can be delivered to the basins, such as the Artesian Basin etc, and let the underground aquaducts do their natural thing in transporting the water around. The water here wont evaporate, and if the rest of the world get's in the act we might help mitigate some of the so called rise in sea levels.
Sounds silly, I originally thought of it in jest, but could be worth a study. Remember if the Romans could transport all the water theey needed by huge constructed aquaducts we shouldn't really find the transportation of water in today's age too difficult. All it needs is money and a will to commit.
