What lessons have we learned?
“The ongoing floods in Queensland and New South Wales are on track to be one of Australia’s worst-ever natural disasters. And if this news isn’t bleak enough, we can expect more extensive and more frequent flooding as climate change intensifies.” reported James Purtill from the ABC, his conclusions made from the latest Climate Council report linking the disasters to global warming. “The Brisbane “rain bomb”, for instance, dropped more water on the city than typically falls in London over an entire year, and the volume flowing through the Brisbane River far exceeded the 2010-11 floods.”
A town like Gympie is synonymous with flooding, built on a floodplain around a busy goldfield only 155 years ago. Gympie floods have always brought heartbreak to shop owners in the middle of Mary Street. Creeks across the region that are dry most of the year, rapidly rise in flood time filling gullies and crossing flats to breach houses, cause erosion and generally wreak havoc in areas that typically you wouldn’t have even realised was a watercourse.
Times like these, it is best to heed the call of local knowledge. Having lived in the community just 15 years, there are many shared flood stories. “Every flood is different,” you hear time and time again. And this is true, depending on where the rain has fallen in the catchment. The Mary River Catchment covers 5 local government areas with many numerous tributaries feeding into the Mary River. The town of Gympie is pretty much in the middle of all that water (or potential water). If rain falls in the upper part of the catchment, this water must travel downstream to find the ocean at River Heads, gathering runoff and gaining height as it progresses.
Cut to February 23, 2022. At 9.30am schools closed, advising the Mary River was above Kidd Bridge in Gympie. This was a clear indicator to locals, that with more extended rain to come right across our catchment, we were most definitely in for a flood.
Gympie’s newest accolade as a ‘growth hotspot’ has introduced lots of new families to our region. In house hunting, these newcomers would have done their research based on the ‘1 in 100-year mapping’ to determine the flood impacts of their new investment.
As citizens we trust that appropriate planning laws prevent developers building where flood water can reach.
So as a new resident, you may feel assured your new home is ‘above flood level’, but there is also a lot of other information to understand with flood emergencies. Such things as – which roads are the first to go under and how many supplies you have at home as you will be isolated from groceries, chemists, and fuel.
The Bureau of Meteorology is Australia’s national weather, climate and water agency. It details official warnings, records rainfall, river heights, wind speeds, forecasts weather (and a lot more). Our national broadcaster, the ABC, is considered the official media source in an emergency. Our local council refers to their website’s Disaster Dashboard for localised information, while social media offer a diverse mix of news and predictions.
So, who do you trust as a community member, when filtering these warnings communicated from a range of media, in respect to your specific location?
With technology underpinning most interactions in our daily lives, is government able to partner effectively with emergency services and independent agencies, to provide current, regular, localised information to residents?
Whose responsibility is it to lead, collate and disseminate this type of information?
The ABC has reported gaps in funding for the BOM and its essential services.
We know emergency services such as the Rural Fire Brigade are frustrated at the centralisation of their operations with continued disregard for local knowledge. (article by J Beatson GL Dec 2021).
When published reports from senior scientists consistently outline the likelihood of ‘Extreme events becoming ordinary’, it raises the question, “what lessons have we learned from this flood to be better prepared in the future?”
As residents we need to take responsibility ourselves to better prepare, but we also need to be able to trust our government is funding and supporting services and infrastructure in the most effective way it can to tackle major disasters, such as these floods, in the future.
James Purtill form the ABC reported:
Flood level records broken
Local records for rainfall, flood levels and flood rescues have been broken.
The “rain bomb” that broke over Brisbane on Friday, February 25, deposited 80 per cent of the region’s annual rainfall within three days.
“When Brisbane flooded in 2010-11, the disaster was reported in the media as a one-in-100-year event. The same happened when Townsville flooded in 2019, Professor Steffen said.
“And now we’ve heard that term applies to the latest bout of flooding,” he said.
“The point is we’re having extreme events more often. ‘Ordinary’ extreme events are occurring now in rapid succession.”
A warmer atmosphere is both more energetic and can hold more water, which “stacks the odds” in favour of extreme rainfall, he said.
“For every one degree of temperature rise, the atmosphere can hold 7 per cent more water.
“The intensity of rainfall will continue to increase on that ratio of 7 per cent for every degree of temperature rise.”
This change is already being observed, he said.
The 2020 CSIRO and Bureau of Meteorology State of the Climate report found the intensity of short-duration extreme rainfall (i.e. flash flooding) had increased by around 10 per cent in some regions.
The recent Intergovernmental Panel on Climate Change (IPCC) report predicted the world was on track to warm by 1.5C in the early 2030s, and by 2C this century.
As the temperature of the atmosphere continues to rise, destructive floods are likely to happen more regularly, Professor Steffen says.
“They would happen at a regularity that would make it difficult to recover in between events — that’s almost happening now.
“The economics of this is going to make a lot of places unviable.”
Currently government in Australia uses the 1/100 AEP (Annual Exceedance Probability -AEP) event, or ‘1 in 100 year flood’, with an appropriate additional height for buildings is designated as having an ‘acceptable’ risk for planning purposes, regardless of the potential consequences of a flood. The report added “1% annual excedance probability (or 1% AEP), are preferred because they avoid the common misconception that a ‘1 in 100 year flood’ for example, can only occur once every 100 years; or that you are ‘safe’ for another 100 years after you experience such an event.
Office of Queensland Chief Scientist’s
(https://www.chiefscientist.qld.gov.au/publications/understanding-floods/chances-of-a-flood)
Article by Lesa Bell
