Agree with most of this Chas,
But can only add, we could do much more on the mitigation side, with myriad small dams on private land, that effectively, do little more than slow down runoff, but particularly, when there is a local flash flood.
These tiny upland dams, would force billions of litres into the local landscape, from where it could slowly drain out in the dry times!
We could consider many more income earning large dams, that then were supplied with much more reliable flows, courtesy of the aforementioned tiny dams.
And nothing would be hurt if they could also generate electricity!
Why even a thirty metre wide two metre high weir, will power thirty homes, 24/7.
And where possible, we should build more protective levies, and often for less money than that shelled out for repairs and remediation work, not to mention the increased premiums, that collect more from everybody; and not just those choosing to live on flood plains and in the path of flood-waters, that could easily, become a far more common events!
Your point about the intellectually challenged wondering into floodwater, is well made, and strange that we've only seen one pollie involved, given the average IQ of pollies?
Perhaps, if were his own car?
Rhrosty.

Rhrosty: Thanks for your comment. My piece was about human behaviour, not flood mitigation, but I note you have advanced your idea about myriad small dams before and it's worth responding. Like contour ploughing, it has been advanced by others as a means of storing floodwaters. But to be effective there would need to be huge numbers (thousands) of these little dams in major catchments like say the Brisbane River, and the economics of building them would be highly unfavourable compared with building a few large dams. They would be suited only to the headwaters (on floodplains, productive land would be affected), and much flood-producing rain can fall below the headwaters as occurred in the Brisbane River flood of 2011. Then, big flows from many tributaries (including the Bremer River) entered the river below Wivenhoe Dam.
I have written before in Online Opinion about flood mitigation, noting that dams and levees are part of the endeavour. But their places should not be over-stated: dams can never hold all the floodwater without prohibitive economic (building) and environmental costs being incurred, and levees can't keep floodwater out of towns in very big floods. So in my view mitigation can't be about trying to 'floodproof' communities. It has to be about getting some relief from the worst of flooding and reducing its frequency in places where floodwaters have no value (ie in towns, as distinct from rural floodplains). Many other measures can be used - land use controls (to stop the problem becoming worse), buybacks of floodprone properties (with buildings then demolished), raising houses, educating people about using flood warnings more effectively, ensuring flood insurance is affordable (which requires effective mitigation), etc. The task is about living with floods as well as controlling water.
None of this, of course, will prevent people driving into floodwaters!
Chas Keys

Hi Chas.
How do El Nino expected this year and less predictable rising sea levels due to climate change your views on planning to avoid flooding over the next 20 years.

All I can say is, what can we do, NOTHING, as you can't legislate against stupidity.

Hi PEST: El Nino tends to bring drier weather and is associated with drought conditions not flooding, so it will not be an issue in relation to flood management.
Sea level rise has been occurring on average around the globe at a rate of 2-3mm per annum over the past century or more, quickening lately, and in recent years it has been the subject in some Australian states of regulation about the floor levels of new buildings. In NSW, though, the state government has relaxed the floor level regulations instituted by its predecessor.
If sea level continues to rise over coming decades (and the recent revelations about melting in West Antarctica give no comfort) there will be more coastal erosion when storms create the necessary wave action, and we will eventually have to consider retreat strategies as well as higher floor levels. In the past there have been houses lost to a retreating coastline, in places like the NSW north coast where a small village called Sheltering Palms was claimed by erosion in the 1970s. Earlier, a whole street of houses was lost at Belongil Spit). I can't see this sort of thing becoming less of a problem in the future and the building of sea walls or rock embankments will not be wise because it will exacerbate the erosion at the point the walls/rocks end. You can't put rocks all the way along the dunes of eastern Australia!
Higher sea levels, by retarding flood drainage via rivers, will also exacerbate the problem of estuarine flooding. Many people live in such areas. Low-lying Ballina, for example, is at some risk from rising sea levels and from the Richmond River.
The trouble is that sea level rise occurs only very slowly in terms of human life spans, which reduces the visibility of the impacts and renders effective policy response difficult. Nobody wants to think far ahead. So far, most of Australia has passed on the management of flooding and coastal erosion to future generations and my guess is that we will continue to do that for some time yet.