Climate report issued this week by UNSW Climate Change Centre …

Comment on Stand by for fresh Todd dam controversy by Ian Sharp.

Climate report issued this week by UNSW Climate Change Centre indicates desert areas may become wetter, but certainly likely to have more extreme events which would include heavy rains and therefore floods.
So the “mythical” 1:100 flood event may be on its way, it would be devastating for the town. The biggest flood that I can recall was the Easter ’88 one, both the Stott Tcce bridge and the Wills Tcce walkway were closed, helo rescue attempts to save river campers, lots of local flooding including up our driveway in lower Mistetoe.
I towed out a few sedans conked out around the Undoolya – Grevillea roundabout. And the 88 flood was not a 1:100 event, smaller.
Time to get thinking on a workable strategy. Levees are possible, but complicated by site factors and the need for closable gates in some locations where ramps not practicable eg Wills Tce.
I think a flood mitigation dam at Junction waterhole is a good option, the 1990s head works still there.
The earlier proposal for a dam at the Telegraph station needed a long containment berm as well as the actual dam across the river.
A properly engineered and maintained flood mitigation dam should merely spread the flood peak over a few days instead of a few hours, and not unduly disrupt the ecology of the river anymore than it is already.
Note: By Flood Mitigation dam I mean one designed just for that purpose, not one that doubles as a potential recreation lake … we should learn from past mistakes.

Ian Sharp Also Commented

Stand by for fresh Todd dam controversy
“Cleaning” the river useless against a big flood. A 1:100 plus flood would scour the bed all by itself, no assistance required from us, as well as ripping a channel through to the coolabah swamp and flooding that to depth of at least 3 metres.
As for it being “mythical” – a 1:100 flood is a certainty, we just don’t know when.
And there is nothing magical about that 1:100 figure, it’s not an upper limit to the size of possible flood events, it was just selected as a reasonable design criteria for the proposed flood mitigation dam.
It would be next to useless against a 1:200 year event.
The only long term solution is to gradually shift the built up area off the flood plain.
Or accept the risk and live with it as best we can. A 1:100 dam at Junction Waterhole would be very useful protection against the most common flood events.


Stand by for fresh Todd dam controversy
A dam at Junction Waterhole would have some merit as a flood mitigation measure. But as we saw in 91-2 it is unlikely to get the nod from the TOs unless it is purely for flood mitigation, not a recreation lake in disguise.
That dam was designed to mitigate a 1:100 flood event, which is pretty big, but as Rod Cramer points out Nature doesn’t always limit itself to our designs. The Todd inland delta floodout sand sheets near the airport indicate that there have been much bigger flows over the centuries … but you can’t build a dam for 1:1000 flood.
Perhaps at some point in the future our town will suffer huge flood damage, despite our best efforts now. Locating the town centre on the flood plain was a good idea in the 1890s, to access the water table with shallow wells, but we are stuck with it now. TIO still offering flood insurance to those on the flood plain?


Recent Comments by Ian Sharp

The Base turns 50, will survive Trump
Charlie Carter, spot on!


Thinking big, anyone?
To justify the huge investment (which would be funded how?) we would have to make huge amounts of steel.
Markets for this steel? North Asian countries are our biggest markets for iron ore to feed their steel mills.
Would they be willing to let their steel industries be replaced by ours?
And why railroads? Transport of huge quantities of low value commodities over these distances cheaper by sea in bulk-carriers.
A great armchair geographer’s scenario, even less realistic than the Bradfield scheme, IMHO.


Conservative vote: Territory Alliance up, CLP down in Johnston
Joel is not an academic, he’s been a student getting qualifications to increase his knowledge.
Academics work in tertiary institutions, teach and do research.
As well as having been a footballer at the highest level he has been a small business owner.
He grew up in The NT, and lived at Ernabella for a time with his family.
He married his childhood sweetheart, an Alice Springs girl.
Not a bad resume for an NT politician.
Better than many who have served in the NT Parliament over the years. We have had too many blow-ins on the make, the last one was the Chief Minister who oversaw the Port of Darwin lease to a Chinese company.
Joel, a Territory boy, been away, made good, back to help the NT grow in away that all benefit. More power to him.


Epistle from the inferno
Crikey, Charlie, what a harrowing time for you both. Hope things on the improve, may the rain and Todd flowing sooth you a little. Best wishes.


War on Iran must be prevented
Great comments, Kieran, spot on. The only thing Matthew had going for him was the courage not to hide behind a pseudonym. And Jonathon Pilbrow is right, we must learn the lessons from the Iraq folly. If we had a time machine we would certainly go back and make different choices. I applaud Jonathon and his group for reminding us of the risks we take in blindly following the US into conflicts where there is no prospect of a positive outcome. For anybody.


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