A new report sheds light on risks and precautions for Gold Coast residents.
Floods cost Australia more than any other type of natural disaster, averaging hundreds of millions of dollars per year. We cannot stop floods from happening but there are many things that we can do to manage our flood risk and reduce the negative impact of floods. A new report, entitled Understanding Floods: Questions and Answers, brings together for the first time all the latest information that we have on floods and how to cope with them.
From December 2010 to January 2011, Western Australia, Victoria, New South Wales and Queensland experienced widespread flooding. There was extensive damage to both public and private property, towns were evacuated, and 37 lives were lost, 35 of those in Queensland. Three quarters of Queensland was declared a disaster zone, an area greater than France and Germany combined, and the total cost to the Australian economy has been estimated at more than $30 billion.
The immediate impacts of flooding include loss of human life, damage to property, destruction of crops, loss of livestock, and deterioration of health conditions owing to waterborne diseases. As communication links and infrastructure such as power plants, roads and bridges are damaged and disrupted, some economic activities may come to a standstill, people are forced to leave their homes and normal life is disrupted.
Similarly, disruption to industry can lead to loss of livelihoods. Damage to infrastructure also causes long-term impacts, such as disruptions to supplies of clean water, wastewater treatment, electricity, transport, communication, education and health care.
The Queensland Chief Scientist Dr Geoff Garrett AO, convened the Queensland Floods Science, Engineering and Technology (SET) Panel to prepare a report explaining fundamental concepts of floods in clear and simple language. The panel’s report, Understanding Floods: Questions and Answers, focuses on a number of critical, underlying questions important for improving our understanding of and preparedness for floods in the future.
Because flood events are influenced by a number of factors, based on the current science it is difficult to confidently state that, overall, extreme flood events in Queensland will increase in intensity or frequency as a result of climate change. However, increased coastal inundation from sea level rise and increased chance of flash flooding, ) because of an increase in short-term heavy rainfall events both seem highly likely, based on current assessments of projected climate change.
If La Niña events, or their effects on Queensland rainfall, became more frequent or more intense because of global warming, we can expect more frequent flooding. Currently it is projected that, in the future, ENSO variations may be different from those in the recent past.
However, we are not currently able to project confidently what those changes will be.
Global warming is expected to lead to sea level rise, increasing the risk of flooding near the coast, including the lower reaches of coastal rivers.
Any increase in the frequency or intensity of storms could lead to increased storm surge risks, and this would exacerbate the increased likelihood of coastal inundation arising from projected sea level rise. The future will see Australia’s population continue to grow, placing increased pressures on our waterways, many of which already experience high levels of flood risk. A growing population will result in increased development on the floodplain and the temptation to build in flood corridors. Rising land prices and a resulting move to smaller block sizes are expected to result in our cities becoming more densely populated, increasing the chance of flooding in the cities. More houses built closer together increases the number of houses potentially exposed to flood damage.
In the future, cities and towns designed in a water sensitive manner and using integrated water planning may use less drinkable water, potentially allowing us to manage our dam water levels with more flexibility.
