The April report — its release just ahead of the federal election offers a clue to its purpose — listed Nicholls as the most at-risk federal electorate in the entire country. This astonishing claim reared its head again in a 60 Minutes segment on Nine this week.
The report would be laughable if its damaging effects on our community weren’t so serious. It has profound shortcomings: at best it is sloppy and based on flawed, generalised assumptions; at worst it is hugely destructive to property values in our region and ensures that home insurance will be out of reach for many local citizens.
The report — titled Uninsurable Nation: Australia’s most climate vulnerable places — is based on data sourced from a Sydney company, Climate Valuations. Apparently based on desktop research, it has produced a ranking of the top 10 most “at risk” electorates, based on the percentage of “high risk” properties in each electorate.
What constitutes “high risk” is never precisely explained.
Nicholls heads the list because it supposedly has the highest percentage of “high risk” properties in it. Out of 94,280 properties in the electorate, the report claims 27.4 per cent are at “high risk” and around 25,000 properties will be uninsurable by 2030, owing to the risk of flooding.
Given just 900 homes were damaged in the 2022 flood — all of them built before the 1995 planning controls requiring floor levels to be 300mm above the one-in-100-year flood level — this is an extraordinary number.
There is nothing in the report to back it up.
The report simply says: “A warmer atmosphere can hold more moisture and has more energy to fuel storms. With climate change we are getting more of our rain in the form of intense downpours, raising the risk of flooding.”
The report says the data used to develop the risk ranking used “Climate Risk Engines”, which supposedly combine long-term data from local meteorological stations with information about the specific location, such as flood mapping and depths, elevation above sea level and other factors.
If this is true, local agencies and council are unable to fathom how these conclusions could be reached.
The 2022 flood was a one-in-50-year flood event, similar to the 1974 flood. There has been no obvious increase in flood levels in the five decades since. The report elsewhere acknowledges that rainfall in the south-east of Australia is in a long-term declining trend.
In October, 2022 the Goulburn peaked at 12.1 metres at Shepparton, with a flow rate of 186,000 megalitres a day. To flood the 90 per cent of Shepparton houses considered “high risk” by the Climate Council, the river would need to exceed 12.8m — that is, 700mm higher.
This would be equivalent to a one-in-500-year flood, with a river flow rate of around 320,000 megalitres a day — 72 per cent more than the 2022 flood! Nothing remotely like this has ever been recorded and the massive rain event required to cause it would be unlike anything Victoria has ever seen.
The rating curve that shows how river flows relate to river levels is publicly available data, as are our building heights — none of which the Climate Council’s modellers bothered to check.
The report is alarmist, based on lazy, broad-brush assumptions without regard to actual data and our mitigation efforts over many decades. It is a disgrace.
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