Where is Queensland going with flood management?

Restricting further urban development on floodplains will be politically difficult, however. It will be strongly opposed by development interests which will complain about the 'sterilisation' of floodplains and indicate that building costs will rise if easily-developable sites are denied. But the true cost of housing in flood-prone areas must include the costs of flood recovery, which developers do not have to bear. They are borne by individuals and the public purse.

Not to make progress in this regard will be to admit that we are party to the wilful exacerbation of the problem of flooding. Worse, we will do this in an era when we know full well that further urban development on floodplains is guaranteed to increase community vulnerability. It will also guarantee the spending of large sums of money on relief and recovery measures and increase the demand for additional flood mitigation spending. Better, surely, to seek in future to avoid these things in the first place.

Not to reduce the further use of floodplains for urban expansion will involve a dreadful admission about how we govern land management. In effect it will say that our approach to urban development is economically eccentric. We will be committing ourselves knowingly to increasingly high costs to support those whose properties have been flooded and to replace items of infrastructure that have been damaged or destroyed. That we have persisted for decades with an economically irrational development mindset here must be recognised.

All this applies to redevelopment too. As the older parts of flood-liable towns and cities come up for redevelopment, an opportunity exists to wind back the problem bequeathed to us by past generations. We have two choices here: to re-build more effectively (for example by mandating higher floors and more flood-resistant building materials) or to require that only flood-compatible land uses are permitted.

What should definitely be avoided is the re-creation of what will in effect be whole new suburbs in redeveloped areas. Having large numbers of people living in high-set dwellings above floodwaters, potentially for days, would be ill-advised: the failure of normal power, water supply and sewerage services will render these areas uncomfortable during floods. And if fire should break out - not an uncommon occurrence during floods - such dwellings could become death traps. Superstorm Sandy six months ago in the eastern USA saw people die because fires in flooded areas could not be dealt with appropriately as a consequence of access difficulties.

Planning major new developments on floodplains, even if the floors of dwellings are elevated, is dangerous. People living in such housing are likely to consider themselves safe and often they will not see the need to evacuate as floods approach. Allowing such estates could be said to amount to a policy of 'deliberate entrapment' of the residents come flooding.

Whether we are talking about new development on the outskirts of towns and cities or redevelopment in their older areas, stopping the problem from getting ever larger and more costly would be one of the best flood mitigation measures we could take.

But the problem of the legacy of past decisions about land use will remain whatever we do about future development. Dealing effectively with the existing problem will require that flood warning systems are improved. Here the difficulty is not so much any lack of gauges to provide data from which to measure and model flood severity, or indeed the accuracy of flood predictions for communities in the path of coming floods. In the main these matters are well managed already.

The real problem is that too many people fail to understand the warnings they receive. Hence they tend to delay their responses (lifting items within houses or evacuating to safety) until they can see the floodwaters encroaching on them. All too often the results are that much of material and sentimental value that could be protected before inundation occurs is lost and that people evacuate through dangerous floodwaters when ideally they should have left earlier, before their escape routes were inundated. A crying need here is for better information on the likely flood consequences in an area to be attached to messages about forecast flood heights. This is rarely done well in Australia.

In addition, people need to be educated on the nature of the flood threat in their vicinity, how severe it might be in the rare very big floods, what they should do to prepare and what to do when they receive a warning of an approaching flood. An understanding of these matters will unlock the unrealised potential of flood warnings to limit damage and promote personal safety. There is good information in Queensland on the website of the Bureau of Meteorology and some councils have produced brochures on what people should do come flood time, but the educational effort so far has been both piecemeal and poorly co-ordinated.

Education about the nature of levees, including the fact that levee failure or overtopping can occur, is also needed. To date, people living behind levees have been allowed to believe that they are protected from all flooding. Sadly, every levee in Australia will be overtopped at some stage and some are likely to fail.

Truly effective flood mitigation will utilise a range of approaches, both structural and non-structural. All indications are that the Queensland government is convinced of the need to take the road of structural measures to reduce the severity of the flood problem, but there is little to suggest that it comprehends that more is necessary if genuinely high-quality mitigation are to be achieved.