Soon after the February flood, local member Kevin Hogan announced a CSIRO study to be followed by $75m to ‘implement the findings of flood mitigation studies‘. CSIRO factsheets reveal that it will take two years to produce a hydrodynamic catchment model. Lismore’s recovery cannot wait two years, so we need to act on other evidence that events like the February flood cannot be mitigated, and need to judge the risk of such big floods recurring.
It was ‘the biggest flood in recorded history‘, but only by a small margin. Newspaper reports at the time indicate that during the 1870 flood there was ‘three inches of water in Mr Coleman’s store‘, from which we can infer a flood height of 13.9m, consistent with oral history of water ‘that went over Cathedral Hill‘ (in Dawson Street).
Last February’s flood was the biggest, but there have been five floods over 13m in Lismore’s 160-year history, so we should expect that the risk of a such a flood is about three per cent in any year (much better odds than the pub raffle). And we should not expect that such floods will be 30 years apart, as two 13m floods have occurred within three years, in 1889 and 1892. As David Witherdin said ‘is that really how you want to spend your life?‘
It’s not just the height of the water that is the issue – but also that bigger floods have higher velocity (speed) causing more destruction, and that the flood peak arrives more quickly. In February, there was only about four hours between the deluge in Dunoon and the levee overtopping, compared to lesser floods that may have up to 40 hours between the rain event and the flood reaching the levee in Lismore. Those who choose to remain in the flood zone, need to be mindful that the time window to escape or for rescue can be very small for big floods.
The decision to stay or move is not solely about the risk appetite of individuals. Many people cannot afford to leave, and although the recently announced buyback scheme provides some options, it may not be sufficient to buy a replacement elsewhere, and doesn’t empower renters to relocate. For the broader Lismore community to recover, the buyback could include incentives for people to remain in Lismore, and not migrate away. It should consider ways to maintain existing communities, in consultation with these communities, perhaps through group housing projects. Many people have a strong attachment to the site of their former home, and we should find ways to help maintain this, perhaps through community gardens or allotment gardens that are flood-tolerant. The risks and emotions do not rest solely with individuals. In the February flood, rescuers faced many hazards while assisting others, and many people not directly involved nonetheless were emotionally traumatised. So the recovery and rebuild concerns the broader community, not just individuals directly affected.
For Lismore to thrive and maintain its vibe, flood victims need more than cash for their house; they need an alternative that is viable both financially and socially, so helping to offer alternatives that maintain community identity is an important part of the relocation effort.
♦ Jerry Vanclay is a Professor at Southern Cross University.