Sambo, Re the Murray. I don't really believe the problem has a long term solution. Leastwise the perceived problem as it stands. That being water for irrigation, recreation and for potable usage.
There seems in every argument that the "food bowl of Australia" is at risk and we'll all end up starving from lack of fruit and vegies. If these crops are so water dependent why not just relocate the "food bowl of Australia" to somewhere where there is abundant water .... Like North Queensland. Heaps of land ... doing bugga all ... and heaps of water.
Problem solved, and no $billion expenditure from the feds or states.