FLOOD planning levels used to determine minimum floor levels in building approvals represent an unacceptable risk to residents according to a national flood risk survey.
Flood expert, Steven Molino who is presenting a paper at this week's Floodplain Management Association conference in Batemans Bay, created an online survey to gauge perceptions of acceptable flood risks and he received 400 responses across all Australian states.
"The responses overwhelmingly show that there is a mismatch between current planning and many people's expectations," said Molino Stewart's Managing Director, Steven Molino.
The survey showed photographs of above ground flooding, above floor flooding, ceiling level flooding and a home destroyed by flooding and respondents were asked to indicate an acceptable chance of each happening to them.
Choices ranged from once-a-year to never.
A quarter stated that above ground flooding would never be acceptable yet there are generally no planning controls to prevent this.
The 1 in 100 flood is generally used to set minimum floor levels and has about a 50/50 chance of occurring in an average person's lifetime yet only 3 per cent said a 50/50 chance was acceptable. A massive 71 per cent said it would never be acceptable.
The responses in regard to ceiling level flooding and buildings being permanently damaged by floods suggest that 85 per cent and 91 per cent of people respectively would never want this to happen yet most flood policies don't address these risks.
Although a limitation of the survey was not knowing the actual flood risk at the respondents' properties, they were asked whether they had experienced a flood at this property (13 per cent) or elsewhere (11 per cent) and whether they think their current property could flood (32 per cent). Interestingly, breaking down responses according to flood experience or perceived risk did not make a significant difference to risk acceptance.
There are about 200,000 Australian residential properties affected by 1 in 100 riverine flooding, and at least this many again would be affected by larger floods. Some of the 2011 floods in Queensland were estimated to have a 1 in 1,000 chance of occurring.
"These results suggest that the current flood planning level for above floor flooding is not acceptable to the majority and the community expects a much higher degree of protection from even more severe flood consequences, something which most flood policies don't address," said Mr Molino.
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