The last few years provided plenty of data to help us reform our approach to floods. With devastating flooding in Queensland and Victoria in 2011 and 2013, we should have learned a great deal about which approaches to flood mitigation work and which are less effective. A review of four recent Australian studies of mitigation and adaptation, and a comparison to overseas recommendations, shows we are lagging behind international practises in a number of important areas.
The Australian approach
We looked at four recent reviews of flood mitigation and adaptation in Australia: the Queensland Floods Commission of Inquiry, Brisbane City Council’s Flood Response Review, the Victorian Parliament’s Inquiry into Flood Mitigation Infrastructure in Victoria and the Victorian Floods Review.
These reviews varied greatly in scope, and all produced a comprehensive list of considered and much-needed recommendations to improve Australia’s resilience to floods in the future. But one surprising fact was none of them dealt with future climate impacts. Some didn’t even mention climate change. Government reviews are expensive, but the cost is justified if they identify reforms which improve society. By not taking into account the risk of future climate change and its exacerbation of flood risk, governments are missing an opportunity to include those risks in the current reform agenda.
Australian governments take the attitude that we can re-make flooded communities exactly as they were before. As soon as a disaster is declared, federal funds are made available to rebuild to “pre-disaster” conditions. There is little or no expectation that infrastructure should be made more resistant to flood damage. In the United States 15% of federal funding is allocated for “betterment”; here there are virtually no resources to plan for, relocate or strengthen flood prone infrastructure to make it more resilient.
The Australian approach to “flood proofing” communities is to build levees. Levees essentially take the same body of water and squeeze it into a smaller space. They don’t encourage evaporation, and they push water to higher levels. They work well in small floods, and under those conditions are very effective at protecting communities. But in recent years we’ve seen bigger floods, and these are likely to get worse. In bigger floods the levees are often overcome, and the potential for serious damage becomes much greater than it would be without them.
“Non-structural” or “ecosystem” approaches to flood mitigation work much better than structural measures like levees. But in Australia, we rarely consider these types of measures.
Internationally, the story is very different.
In our research we also looked at flood reforms in the USA, China and the Netherlands. In all three, climate change was a driving force behind their significant recommended reforms.
All of these countries recognise they have reached the limit of what levee banks can usefully achieve. Instead, they have instigated a range of reforms built around the concept of ecosystem management.
The first of these is “making room for the river”. The river channel is widened or deepened to allow more water to flow through while remaining within its bounds. Flooding of surrounding areas is reduced.
Since its devastating floods in the 1990s, China has been restoring flood plains, buying land around river channels and relocating people to higher ground. This has happened most famously as part of the Three Gorges Dam development, which attracted a lot of negative media coverage. But we’re finding that years after relocation, people have shifted to crops that are less prone to flood damage which, combined with being on higher ground, means they’re hit by floods less often, and they’re better prepared to deal with those that come along.
All three countries have changed the way they manage their floodways. Where cities and towns are vulnerable, the government diverts the river into agricultural land around the town. In a flood season the city is protected and agricultural areas are flooded instead. The farming communities are paid by the government to forgo income during floods, but still use the land at all other times. Australian research has shown that for graziers, more frequent flooding can actually improve farm incomes.
What could Australia learn?
Australia has dabbled in ecosystem approaches and relocation, but often in an ad-hoc way.
Critics of ecosystem approaches point out that it’s all very well to deepen a river upstream, but if you don’t deal with the towns downstream, flooding there will be much worse. For ecosystem approaches to work, management and planning have to be undertaken on a much larger scale.
In the southern Murray-Darling Basin, the government proposes removing constraints such as bridges and dams to allow for bigger peak environmental flows (that is, floods). This work is very promising, but what about the rest of the Murray-Darling Basin and, indeed, the rest of the country?
Currently, we don’t have coordination and integration across jurisdictions within and between states. But rivers don’t respect administrative boundaries: when you’re developing ecosystem approaches, you have to use the natural environment as your point of reference.
There have also been a few examples of relocating communities: Grantham and Gundagai being the most notable. This relocation is expensive, but as floods become bigger and more frequent it’s something Australia needs to do more often. The financial and social costs of retaining and rebuilding flood prone towns over and over and over again will soon add up. When the taxpayer is picking up the bill, at some point you must decide whether rebuilding is an economically viable solution, or whether in some situations relocation is the more sensible approach.
And of course we must take account of future climate risks. While none of these reviews seriously studied those risks, change is happening elsewhere. The Australian Rainfall and Runoff Guide is one of the most important national reference guides, and is used by planners and builders to help them allow for floods. It’s currently under review, and future versions will take account of the effects of both natural and anthropogenic climate change. This attitude should spread to all flood reform.
Karen Hussey receives funding from the National Climate Change Adaptation Research Facility.
Jamie Pittock receives funding from the National Climate Change Adaptation Research Facility.
This article was originally published at The Conversation.
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