Finding flood solutions for the future
Why we are still depending on 18th century technology to fight 21st century flood events is questioned by Mark Bowater, director of Tiger Dams.
There was much debate after the 2011 floods about what immediate strategies should be employed to ensure Australians never again had to face the traumatic consequences of poorly planned flood mitigation. Two years on, however, Brisbane stood on the precipice of a disaster of near-equal proportions while watching regional Queensland being inundated once again.
These events in Queensland should have changed the thought processes of anyone living in a potential flood zone, particularly in regard to forward planning for the next event. The concept of ‘one in 100-year flood’ has been proven to be a misnomer, with some areas being severely flood affected more than three times within two years.
There can be little doubt that any record flood levels, which governments at all levels use as their benchmark for their own disaster management strategies, are a thing of the past. Previous flood records are not just being surpassed; they are being smashed by a long way. The consequence of that is that areas are being flooded that have previously been relatively safe from severe damage.
How did this happen? The response should have been immediate and effective, yet we were caught off-guard again. Isn’t it time governments ceased depending on 18th century technology to fight 21st century flood events?
SANDBAGS AREN’T THE SOLUTION
Sandbags have been in use since the middle of the 18th century. Other than changing to newer, arguably less useful materials to make them, they essentially haven’t changed. Nor has the way we use them in a flood emergency.
The usual procedure is that local government or emergency services such as the SES (state emergency services) will have a supply of sandbags, and a stockpile of soil or sand to fill them. Members of the public queue for as long as it takes to get a limited supply of sandbags, fill them on-site, and then transport the now heavy sandbags back to where they need to be deployed.
Most people think that water must be moving at some sort of velocity for a sandbag wall to fail. Unfortunately, that is not the case. Water has mass, which means the sheer weight of water against a poorly designed sandbag structure will eventually push it over. Consequently, all the hard work in building a sandbag wall will simply have been in vain.
The truth is that, like any other structure, a sandbag wall has to be properly constructed to successfully keep floodwaters at bay. To get them right, they need a substantial foundation, preferably ‘keyed in’ to the surface, so water cannot get under the structure. Sandbags need to be properly stacked so that they interlock properly to give the best seal and strength. And, of course, they work best if they can be sealed with plastic sheeting.
Add to that the various occupational health and safety (OH&S) injuries experienced after the fact by people simply not used to that kind of manual labour, and you have an inefficient system that simply doesn’t do what people expect it to do. In addition, they end up in landfill after the event, becoming an environmental problem, as well as harbouring disease and bacteria from the floodwaters.
WHAT IS THE SOLUTION?
The Federal Government is quick to make noise about preparation and long-term solutions after flood events, but it is high time the best solutions were brought to the table.
In 2010-11 only $26 million of Federal Government annual spending was allocated to disaster mitigation. Yet, in the same period, state and federal government emergency payments exceeded $1 billion. The damage toll caused by the flood disaster in January 2013 was about $2.4 billion.
The Insurance Council of Australia’s view is the Queensland State Government’s flood mitigation budget was insufficient. Queensland’s Premier Campbell Newman agrees more must be done to find engineering and alternative solutions to protect our communities and make them more resilient.
All parties agree much more needs to be done to alleviate the state’s flood problem, but the current debate over solutions leaves many questions unanswered.
While permanent flood levees are well- intentioned, they only address half the problem. It’s not practical in some situations to build permanent flood levees, nor is it possible to levee-protect businesses in floodplain suburbs. At the onset of flooding events, these areas require responsive flood-mitigation strategies.
There are systems used extensively around the world that are recognised for their quick deployment and flexibility – two critical elements in protecting against natural flood disasters. They use heavy-duty interlocked tubing that is filled with water to create a flood-mitigation barrier to secure buildings and infrastructure, divert river flow and
protect river banks. These systems are set up in one-fifth the time of sandbags at less than a third of the cost and withstand high velocity riverine currents, giant logs and intensive wave testing. And they are over-topped without failure. The damage limitation demonstrated by such cost-effective solutions should be enough evidence to warrant government consideration.
FLEXIBLE ALTERNATIVES REQUIRED
As we debate the long-term solutions needed to relieve Australia of its flood headache, it makes sense to look at these responsive, flexible alternatives that provide immediate protection as well as reliable future defence against flooding.
When we talk about reducing the trauma to a community after a disaster, the focus needs to be on protecting the foundations of the town – reducing the time it takes to rebuild communities. Providing our emergency services with the right armoury will help them to respond to disasters more effectively.
Emergency response trailers, for example, serve this very purpose. Fitted out with the necessary equipment to erect a rapid flood barrier, these mobile trailers can be instantly deployed to areas with high flood concern.
While governments and emergency services can do much to help communities during a disaster, the bottom line is all of us need to do our part to protect our lives, properties and economy. Key sectors such as agriculture, small business and mining must accept responsibility for their own flood protection. Preparedness is just like buying insurance.
Encouragement of a national agreement on funding and a discussion on a long-term strategy to flood-proof Australia are overdue.