Here is a review from the Department of the Environment

http://www.environment.gov.au/soe/te...s/wateruse.pdf

Which says amongst other things:
"The appreciation of such economic and environmental costs is now very much
greater, especially in the context of schemes for urban water supply and
hydro-electric power. However, the same cannot be said of water storage for
irrigation, particularly in terms of pressures to increase supply through the
inland diversion of water from coastal streams. Proposals such as the
Bradfield scheme have involved a number of rivers in Queensland and New South
Wales, especially the Clarence (Cameron McNamara 1982; NSWDWR 1988). There is
no doubt that such proposals are feasible in engineering terms; equally, there
is no doubt that they are not economically viable or environmentally feasible.
As with other irrigation-related schemes, they are predicated on the
assumption that water costs would be subsidised by government. The same
observations apply to proposals to pipe water from the Kimberleys and/or Lake
Argyle to Perth and other southern locations. In Perth, the water would cost
$3.45 per kilolitre compared with $0.53 from south-western sources and $1.80
from desalination "
I am not saying this document is 100% right or the last word on the subject
but at least the author is a professional and it is published by a reasonable
authority.

If you are looking for big thinking have a look at this:

http://www.cecaust.com.au/pubs/pdfs/Water_Projects.pdf

It's a wish list in the form of a map, which looks very spoofy but keep in
mind there are zero costings or environmental impacts supplied.

The Citizens Electoral Lobby is the Australian arm of the American La Rouche
organisation whose grab-bag of ideas and policies (on their main page) are
very interesting. I leave you to draw your own conclusions about how valuable
such views are to the debate.

David