Thinkabit,
In the bushfire scenario firebreaks and the removal of combustible undergrowth are the way to go for safety, without adequate fire breaks and clearing in the vicinity of dwellings there is sure disaster, yet the State will not allow adequate clearing, that is those not affected effect a barrier against safety, when that barrier causes loss then should not the instigators of the barrier share the blame and give financial assistance to the victims of their stupidity?

Levees are a short-term solution & should be continually built up & wider. We produce so much waste which could be mulched & mixed with concrete to make solid land fill to help raise the ground to build on. There should be no more new building in flood prone areas full stop ! Waterways should be widened & banks built up. It should be legislated that building waste should be taken to such areas & disposing of it there should be cost-free.
That'd be step 1 in reducing flooding.

Drove my Chevy to the levee
But the levee was dry
Them good old boys were drinking whiskey and rye
Singing, "This'll be the day that I die"
This will be the day that I die.

The problem is not more levee's, but climate change and the disasters it is causing around the world, including in Australia.

YES!!That’s it.
Climate change! but what is responsible for all the great flood plains?

Indyvidual,
Levees are a permanent solution except for those thrown up in haste in front of rising flood waters.
A ban on new buildings would affect more than half of both NSW and Victoria and would be impratical.

Oh, we are pilgrims here below
Down by the riverside
Oh, soon to glory we will go
Down by... the riverside.

These floods are UNPRECEDENTED. Although according to our forum friend Ossie Ostrich and the coal burning brigade, just stick your heard in the sand, sorry mud, and all will be well. BTW, has anyone got the plans for the 'Tower of Babel', now there's a fix.

Is Mise: "when that barrier causes loss then should not the instigators of the barrier share the blame and give financial assistance to the victims of their stupidity?"

In my opinion it depends in the details. But to give a couple of examples that outline the general principle of being responsible for your own risk taking:
1) If you buy a property that it is next to a National/State park AND it is clear to anyone with commonsense that it is a massive fire risk because is not actively managed then if your place burns down then it is your fault.
2) On the other hand, if you own a property next to a bit of bush and historically (prior to the time you bought it) and currently (at the time that your placed burned) the government has a legislated requirement to manage the risk AND it has failed to actively adequately fulfill this requirement then in this case the government could possibly be held responsible.

By-the-way: I vaguely remember that a few years ago here in Queensland that the State Government introduced some laws permitting you (in a restricted fashion) to clear firebreaks on the their side of the fence for bushland they own. Don't know the exact details, and I could be completely wrong about this.