Brought to you by Cosmos Magazine and The Echo
As the threat of extreme weather events increases, Lismore – a city that has suffered its share of historic floods – debates whether the official flood planning levels need to be increased to meet what the future might bring.
Lismore City Council trumpeted the start of a “return to normal” this week after the record floods of 2022, but has moved to recommend higher minimum floor levels for buildings in the town.
Consultants updating regional flood mapping had last month tabled a report recommending a higher Flood Planning Level (FPL) be set to allow for potentially bigger floods under climate change.
In March, the proposed changes will go to public exhibition along with the consultants’ report, a move that may go some way to ensuring a future for the settlement.
But restoring the health and wellbeing of some of the town’s residents may take a little longer.
The heart of Lismore’s CBD was busier than I’d imagined.
Car parks were full, a bluegrass banjo player picked Soldier’s Joy from the footpath, and business owners, shoppers and café goers were (incredibly) smiling despite the events of 2022.
Some shops remained closed and empty, but many thrived.
In fact, walking down Lismore’s Keen St for coffee at Henry’s Bakery last month, I was tempted to wonder if anything had really changed at all.
My daughter was born at Lismore Base Hospital, and I’d lived and taught in the town for five years until late 1993.
Then I noticed the many small blue and white survey markers still affixed on some power poles at heights that rivalled the roof lines of nearby buildings, a reminder of how high floods had reached in the 1974 floods.
And with every step thereafter came to mind a terrifying, almost impossible image of water in the street swirling to a full two metres higher than those tell-tale markers.
Lismore has a long history of flooding, with at least 138 events in the past 152 years.
Located on the lands of the Bundjalung nation, the town’s vulnerability to flooding stems from a complex set of modern factors, starting with its location as an inland port at the confluence of two rivers during the 19th century.
Today a city of almost 44,000, its average annual rainfall tips 1800 mm compared with 600mm Australia-wide.
During heavy rains, high hills surrounding Lismore return correspondingly high volumes of runoff via steep creeks to the Wilsons River and Leycester Creek, two main flood ways that join at the town.
Their combined flows navigate the Richmond River to the smaller town of Coraki before crossing a coastal floodplain to the sea at the tourist port of Ballina.
The catchment area for the Wilsons River is more than 550km2, but when Leycester Creek’s watershed is added, the catchment above Lismore climbs to 1,400 km2.
Add to these factors the growth of urban development in flood plains, changes over the years to the rivers’ profiles as well as to catchment topography and land use, and the building of levee banks to protect at-risk properties, and there emerges a complex picture of flood risk.
Read more: Floodwaters essential for ecosystem rejuvenation say experts.
Big floods, like those on Australia’s eastern seaboard in 2022, happen more often during wet La Niña years, with climate change predicted to impact their frequency, intensity, and impact.
On the morning of Monday, 28 February, 2022, many Lismore people woke to some homes already flooded, and it was too late to evacuate.
The Wilson River had peaked at 14.4m, the highest flood in recorded history, more than 2 metres higher than previous records set in 1954 and 1974, and well above the town’s 10-metre-high levee wall, constructed in 2005.
Then in March it happened again – a lower peak this time but arriving while many were still cleaning up from February.
It hadn’t seemed that long since the last near record flood of 11.59m, in 2017.
The rebuild and repair bill for combined Lismore inundations of 2022 was estimated at $1 billion, a reminder that flooding is hellishly expensive.
Australia-wide in the 10 years to 2016, flooding cost us $18.2 billion per year on average, equivalent to 1.2% of average gross domestic product (GDP), a figure only likely to rise under climate change.
Alarmingly, the Intergovernmental Panel on Climate Change (IPCC) predicts a doubling of flooding associated with global warming of 2oC by 2100.
Even under a low emissions scenario, the cost of all types of natural disasters in Australia is expected to increase to $73 billion per year by 2060.
Which goes some way to explaining the question on many Australians’ lips this past year: Should Lismore rebuild or relocate?
If research emerging this past month is any indication, so far it’s largely the former, despite a government buyback and retrofitting scheme started late October.
A Lismore City Council occupancy audit published this week measured occupancy rates at 60% across the CBD at the end of January, compared with just 38.3% in August.
The figures were cause for hope, according to Lismore mayor Steve Kreig.
“This audit shows promising growth in the number of local businesses and organisations operating in the CBD,” Krieg said.
“It’s fair to say that we are well on the way to our pre-flood occupation rate of 90.2%.”
But problems persist, and in a separate survey released last week by Southern Cross University, researchers found that almost half of flood victims reported being still displaced by December.
Of 800 respondents to the SCU survey, more than half had moved back into a home that had flooded, 26% were living either in caravans, sheds, or pods, or with friends and family; 18% were in insecure or crisis accommodation such as tents or temporary rentals; and 4% had left the region.
Moreover, executive director of non-profit community group Resilient Lismore Elly Bird said only 20 percent of respondents were coping with the stresses and challenges of recovering from the floods.
“More than 80 per cent agree that community hubs have been essential to their recovery,” Bird says.
Is it any wonder?
Five lives were lost in the 2022 Lismore floods.
More than 31,000 people were displaced, 3000 businesses disrupted, and water, sewage, and power utilities were extensively damaged.
According to a June 2022 review of the emergency, some 18,000 jobs were affected, almost 1000 of them agricultural, nearly 1400 houses in Lismore were damaged and at least 37 destroyed.
An estimated 90% of the district’s 1200km road network was eroded or washed out.
Other areas of NSW and southeast Queensland were also flooded, prompting the NSW Government to commission an independent expert inquiry into events across NSW, published in August.
A multi-million dollar CSIRO flood mitigation study of the Northern Rivers was commissioned in April, and commenced community and stakeholder consultation in October.
But the herculean challenges faced by first responders, relief workers, volunteers and recovery teams remain quite unthinkable.
Now, on the eve of the first anniversary of the record flood, the community faces what may prove its greatest challenge: How do we plan for climate change?
Read more: Rebuilding for flood resilience.
The planning challenge was made public last month when an interim flood planning report was tabled at a committee meeting of Lismore City Council (LCC) on 24 January.
Prepared by Brisbane-based water and environmental consultants Engeny Water Management Pty Ltd, a Lismore Floodplain Risk Management Plan (FRMP) had first been commissioned in 2021 but flooding in 2022 delayed the work.
Last month’s interim report made recommendations to help LCC begin shaping its land use planning and development controls for a future Lismore.
It also reported on further computer modelling for higher return period floods than the 1% or 1 in 100 AEP flood, including the simulation of 1 in 1,000, to 1 in 100,000 AEP extreme flood events.
The purpose was to update flood estimates and develop “a full set of flood planning maps for Lismore”.
Hydrologists and land planners use the Annual Exceedance Probability (AEP) to measure how likely it is that a given sized flood might occur in any one year.
The analysis uses historical flood records and computer modelling of past and likely future floods.
According to Queensland’s Chief Scientist, “nearly everywhere in Australia uses the 1% AEP event, or ‘1 in 100 year flood’, with an appropriate additional height (or freeboard) for buildings designated as having an ‘acceptable’ risk for planning purposes.”
Actual flood levels can vary from one location or street to another, and so are mapped to advise residents and insurers of a property’s risk of inundation.
For example, if a street is mapped as being in a 1% AEP flood zone, insurers estimate you have a “50% chance of being flooded in a typical lifetime (70 years), and a 15% chance of being flooded twice in this period”.
This does not necessarily mean you will be flooded once every hundred years, but that there is a 1% chance you might, for any given year, hence the term 1% AEP flood.
Of critical importance is the Flood Planning Level (FPL), a height used to set floor levels for property development in flood-prone areas, which for Lismore is currently set at the 1% AEP flood event plus a freeboard of 500mm.
But as Engeny notes: “IPCC research indicates that long-term weather projections point to increased intensity of rainfall events, and resultant increased risk of flooding.”
The change could raise flood levels by up to 600 mm by 2090.
At its Ordinary Meeting on Tuesday night <14th Feb>, the Lismore City Council agreed to follow Engeny’s lead and recommend raising the FPL to 1% AEP 2090 climate change level plus 500 mm freeboard.
Engeny notes the 1% AEP 2090 Climate Change levels are generally 500-600 mm above current 1% AEP flood levels.
Council advised it will also prepare a draft Development Control Plan (DCP) for Flood Prone Lands, to be publicly exhibited along with Engeny’s Interim Report.
Lismore Councillors are due to be briefed on the matter on 7 March and decide on the dates for public exhibition then, with recommendations to be exhibited for 28 days from mid-March.
Whatever the outcome, it’s clear that the lessons being learned right now by scientists, planners, researchers, and community groups in New South Wales’ Northern Rivers region, are vital to Australia’s future.
This article was originally published on Cosmos Magazine and was written by Glenn Morrison. Dr Glenn Morrison is an award-winning journalist, researcher, and author who has written of Australia’s Centre and North for more than 25 years. A former newspaper editor, he has degrees in Science, Engineering and a PhD in media and cultural studies, and has lectured at several universities. As an adjunct senior research fellow at Charles Darwin University’s Northern Institute he is general editor of Borderlands, a literary journal of the Northern Territory. Glenn has written two books about the Red Centre and lives at Alice Springs.
Lismore has always flooded … whoever prepared
This article knows this.. !! Gaslighting BS ..
Barrow, Barrow, Barrow, why do you do it.
Gaslighting BS you moan, that’s quite cute coming from you.
Yes, Lismore has flooded before but never in the records has it flooded at 14.4metres.
SMH Newspaper 28/2/23 – the wider East Coast Australia Flood Disaster 2022 ( and sadly Lismore the ring side seat so to speak ) is according to insurer Munich RE the fourth most expensive natural disaster in the world in 2022.
And the flood disaster was also the costliest in Australia’s history – AFR Newspaper, ‘East coast floods were Australia’s most expensive natural disaster’ by Michael Read, Nov 30, 2022
“Devastating floods that swept NSW and south-east Queensland this year were the most expensive natural disaster in Australian history, new data shows.
The cost of the floods, which killed almost two dozen people and ravaged the town of Lismore in NSW’s Northern Rivers region, has reached more than $5.65 billion, according to data released by the Insurance Council of Australia (ICA) on Wednesday.
The floods cost more than the 1999 Sydney hailstorm, which did significant damage to an estimated 24,000 homes and 70,000 vehicles, costing insurers $5.57 billion in today’s dollars.
More than 237,000 Australians have lodged insurance claims for the February and March floods, and insurers have paid out 69 per cent of claims associated with the disaster, the ICA says.
Brisbane experienced a record-breaking 677 millimetres of rain in just three days in late February, which caused the Brisbane River to rise to 3.8 metres and led to flooding across the city.
The Wilsons River reached 14.4 metres in the NSW town of Lismore, destroying homes and businesses and leaving four people dead.
The weather system travelled south and transformed into an east coast low, causing intense rainfall throughout Sydney in early March, prompting Warragamba Dam to spill.”
Australia’s five most expensive natural disasters
Table with 3 columns and 5 rows. Currently displaying rows 1 to 5.
Natural disaster Year Cost*
1 East coast floods 2022 $5.65 billion
2 Eastern Sydney hailstorm 1999 $5.57 billion
3 Cyclone Tracy 1974 $5.04 billion
4 Cyclone Dinah 1967 $4.69 billion
5 Newcastle earthquake 1989 $4.24 billion
Pre-2022 natural disasters expressed in 2017 dollars
Table: Michael Read Source: Insurance Council of Australia
And the best that our Barrow can contribute is, “Gaslighting BS”.
Yes it is gaslighting from this Article
Joachim my opinion.. they do nothing
But dooms day propaganda on a regular basis… now FYI it was not lismore’s
Worst flood, 1893 was two meters over
The 22 flood ..this system unfortunately
Stalled of the gold coast and headed south
It was inconceivable that the BOM could
Not foresee this coming ..all updates were
From sydney ..the predicted flood level
Height was 11.23m ..many failing with
The Bom .. instrumentation breakdown
and the F stupid greens who would not
Tick a new Dam ..or nearby suburbs
So the CBD get go elsewhere…
💯 obstructionist.. !! Now Joachim
You believe what you will ..but i for one
Never in my lifetime think we are in
Trouble because of such small temperature
Rise ..so i just purchased a new Tesla
Did the right thing..you know how it is
Joachim ? ..all this alarmist paranoia !
One small issue..to make this electric vehicle
The output of hydrocarbon’s to get it
On the road ..has polluted the atmosphere
More than a petrol or diesel car dos in 20
Years on the road .. fact not fiction
Joachim..look it up yourself ..
But i did the right thing by the planet
Did i not ? And that’s more than most who
Pretend … i minimise my carbon carbon footprint.. example your Guru that
Insufferable Brandt..jet-setting up and down
The east coast Spewing hydrocarbon’s
Over the country side ..whilst lecturing
We are in a climate emergency… that’s
The hypocrisy that most despise..
Barrow, “…now FYI it was not lismore’s Worst flood, 1893 was two meters over The 22 flood”.
Well then, you’ve got all the data on hand, please share with us that official information that the authorities have missed, NOT the Barrow makings up stuff of;
– the “new” official record flood level is what?
– the official source of this “new” official flood level is what?
So after the M1 Dam Wall was built, Lismore had a record 14.4 metres. Must be cow farts!
Build houses on barges that will rise with the floods, with power, water and sewer connections able to be decoupled and sealed?
I presume you think that the leftist god (presumably moloch/ba’al) is angry due to patriarchy, transphobia, white supremacy and the like, and is going to wipe the Earth clean with a flood lasting 40 days and 40 nights so you’re going to build an ark? You will need two gay guys, two lesbians, two trans…..actually……probably shouldn’t bother. But at least you will have a rainbow flag, even if nobody remembers what rainbows actually symbolise.
Looking back on the events of 28/2022, I fear many people will now spend a lot of unnecessary money over future floods in panic.
The effects of a superior (but unfortunately less local-knowledge based) river warning systems, controlling run-off and constructing holding dams etc., [as per the CSIRO report] may obviate these (understandable) nervous knee-jerk reactions.
But of course, in the meantime lots of professionals, politicians, advisors and companies can make a motza over this “bonanza”.
And increased levels are to be … and not to be expected???
One really does wonder what thinking is or isn’t being done.
The climate science tells us that a future increasing warming atmosphere will hold more water and when it rains the high intensity events like we saw in 2022 will repeat.
Building, indeed re-Building, upon on floodplains is not to be entertained.
So you are saying there will be more clouds reflecting sunlight out into space before it hits the ground and turns into heat?
Depends on what they do to the topography to effect drainage. Keep building artificial hills to put houses on, build in low laying areas that act as natural drains…the M1 dam wall…what do people think will happen. It’s as predictable as the Sun rise.
The only flood planning level that matters is the maximum probable flood level, which I have heard stated as 16 metres.
Flood planning is only sensible if it based on science and certainty (of being high enough).
If it is based on opinion/debate and/or guesswork it is not sensible.