They don't have a clue.....

[Peter Ward]

Originally Posted by adman

Peter if it is not rocket science, I would love to hear your proposal for a levee that would protect brisbane from flooding

Not my area of expertise.

I'd deligate that to hydrologists and civil engineers who have the relevant experience.

First protecting the CBD would however seem like a good start.

I have no doubts the subsequent measures may be seen as draconian (eg "levee view" - rather than "waterview")....but... as the old saying goes...if you want to make an omlette, you have to break some eggs.

Less flippantly , 20,000 (maybe 35,000) homes being under water makes the future duty of care of doing nothing, look criminal.

[coldspace]

Originally Posted by Peter Ward

Not my area of expertise.

I'd deligate that to hydrologists and civil engineers who have the relevant experience.

First protecting the CBD would however seem like a good start.

I have no doubts the subsequent measures may be seen as draconian (eg "levee view" - rather than "waterview")....but... as the old saying goes...if you want to make an omlette, you have to break some eggs.

Less flippantly , 20,000 (maybe 35,000) homes being under water makes the future duty of care of doing nothing, look criminal.

Its a big problem, even a massive issue on how to stop it happening again.
Also, the CBD is not that bad of an issue, its the thousands of homes out in the suburbs that are flooded.
Very hard to control over 2 times the volume of Sydney harbour flowing into one dam every day.
Without Wivenhoe the levels would have been up 8mtrs not the 4.3, we would be up sh-t creek if that was the case.
Back to the drawing board.

[Peter Ward]

Originally Posted by coldspace

Its a big problem, even a massive issue on how to stop it happening again...

Agreed.... "risk management" would include the following:

1. assess the probability of future floods
2. assess the vulnerability of populations & critical assets to flooding
3. determine the cost of future losses based on the above.
4. identify ways to reduce those costs (eg Dams. levees, canals, building codes)
5. prioritise flood mittigation measures based on a long term strategy

Bugger...where does high speed broad-band fit into this???

[adman (Adam)]

As you say Peter, not your area of expertise. Yet you seem to have no shortage of advice about how to solve the problem

[Peter Ward]

Originally Posted by adman

As you say Peter, not your area of expertise. Yet you seem to have no shortage of advice about how to solve the problem

And your solution?

Surely you are not saying all those poor familes now with their homes under water need some fibre optical cable to make them feel the Nation is going somewhere?

If there is a flood mitigation response from Canberra, please point me to it.

[supernova1965 (Warren)]

These events can not be stopped it is not possible to avoid floods in a flood plain its like holding up your hands and asking the orbit of the planets to stop people need to come to the realisation that we are not omnipotent and can not stop or control nature we need to work with it and adapt to it we can not make it bend to our will.

[supernova1965 (Warren)]

Originally Posted by Peter Ward

The Mississipi has literally several 1000km's of levees etc...that for the greater part, work.

Those levees actually caused more problems than they solved once the river got through them which will always happen somewhere because the water has to go somewhere they had to knock them down to let the water out

[h0ughy (David)]

Guys - might i remind you that while healthy discussion may be warranted, remember the TOS - no politics, no personal jibes, and be mindful of what you post as what you send out might not be how it is received.

[troypiggo (Troy)]

We just got power back on here last night. I can't believe what I'm reading here.

Have the people here proposing a levee ever been to Brisbane, been up and down the river? If so, were your eyes opened?

A throwaway response to "what is your proposal then?" like "not my area of expertise, I'd leave that up to the civil engineers" is not acceptable by a long way.

[Peter Ward]

Originally Posted by troypiggo

We just got power back on here last night. I can't believe what I'm reading here.

Have the people here proposing a levee ever been to Brisbane, been up and down the river?

Many times. Flood mittigation would be no simple exercise, but I still maintain critical infrastructure and areas could be protected.

The Yanks (god bless 'em) have been working on the problem with a far more massive system for 130+ years. To say it doesn't work there indicates to me you haven't been there...the scale of engineering is truly impressive (an ethos seeming lost in Oz since completion of the Snowy Scheme)

That is not to say they got it 100% right as there have been significant unintended environmental impacts....which are being corrected...and one would think we could learn from their efforts as well as errors.

I don't accept the argument that throwing ones hands up and saying its in the lap of the gods.

Levees, floodways & wing dams can and do work. The Wivenhoe Dam clearly has had a mittigating effect during these recent floods...but more needs to be done

[rat156]

Originally Posted by troypiggo

We just got power back on here last night. I can't believe what I'm reading here.

Have the people here proposing a levee ever been to Brisbane, been up and down the river? If so, were your eyes opened?

A throwaway response to "what is your proposal then?" like "not my area of expertise, I'd leave that up to the civil engineers" is not acceptable by a long way.

Agreed, totally, people who aren't here and are simply looking to shove a knife into a pollie should not comment. The NBN is something that people out here have been crying out for for ages. To say that it's a pink elephant and that we should be spending the money on construction projects is taking an extremely narrow point of view.

The people here in Chinchilla have been flooded twice in the last month, they are coping well, but it must be terrible for them. I'm lucky in that I'm staying in a motel and am merely inconvenienced in that I can't get home or to work.

As I suggested before, why don't you help. Some of you must have some spare cash laying about, why don't you make a contribution to the people that have been affected by the flooding.

I really don't understand the people on this forum who are just looking for a chance to stick the knife in, particularly at a time when people are losing everything that they own, some their lives. The people of Brisbane had a little warning and could have probably moved their most valuable possessions, but they couldn't have moved all their stuff, or their house. The people in the Lockyer valley and Toowoomba etc had no warning. The people here had to evacuate on Monday night in the middle of a raging storm.

Have some sympathy and empathy guys, this is not the time for the blame game, it's a time for giving and helping.

Stuart

[GrahamL]

Stuart

[Peter Ward]

Originally Posted by rat156

Agreed, totally, people who aren't here and are simply looking to shove a knife into a pollie should not comment. The NBN is something that people out here have been crying out for for ages.

Stuart

Stu given the historic record, this awful event was a certainty and to assume it was not going happen shows policy on this to be very much "head in the sand".

I've nothing but sympathy for the poor buggers that have lost so much and have already put my hand in my pocket.

Nations need all sorts of structures, but the NBN looks like fairy floss to me given recent events.

I'll quite happily go on the record for saying we need to get numerous fundamental systems (water, road, rail etc.) in place *before* we spend a motza on a fibre based comms system...which given recent events would have been washed away had it been in place.

[TrevorW]

I'm with you Peter, stuff the fibre optic network, I heard it was going to cost me more for internet when it arrives, costs for broadband is a ripoff now compared to some countries

I was appalled when the WA Govt said they were making a $1m donation to the Qld flood appeal yet they where going to spend $8m upgrading a restaurant and surrounding facilities to accommodate 53 heads of state attending the next GHOGM here

[Kal (Andrew)]

There are two ways to view this subject. The first argument is to use our engineering capabilities to invest in flood mitigation infrastructure, for example Wivenhoe dam. However, if Wivenhoe was designed to operate at a normal capacity of empty (which obviously gives the maximum benefit to flood mitigation) then it would provide no benefit with regards to supplying drinking water or supplying electricity through hydro electric means, which both offer economic benefits. The result, a compromise where the dam is built with 50% being used for drinking water and hydro electic supply, the next 50% up to the spillway being used for flood mitigation, a further 25% capacity while going over the spillway to cater for a 1 in 100,000 year event.

However, even if you were to invest the maximum in flood mitigation infrastructure, there are some areas where dams are simply not practical, and the brisbane river through brisbane has several sources, if you look at a map wivenhoe might affect a quarter (?) of the catchment area. This is where you have a look at the other argument - accept that floods will occur, and learn to live with it. Relocate homes and businesses that are in low lying areas, and restrict buildings in the peripheral areas to buildings that are flood resilient like the classical queenslander house on stilts. Somehow I don't see the pollies as having the balls to relocate tens of thousands of people though.

[Lee]

Levees in Brisbane? Probably possible, but we are built right up to the river in many areas, would have to be some pretty tall structures, over many kilometres. Easier to get out of natures way - not building low-set houses out of pine, paper and plaster on flood plains would be a start.
Then a 1000 year event occurs, a couple of cyclones now might do it, and we get a 7-8m flood despite Wivenhoe, and all bets are off almost regardless of what you do.

[h0ughy (David)]

Originally Posted by Peter Ward

Many times. Flood mittigation would be no simple exercise, but I still maintain critical infrastructure and areas could be protected.

The Yanks (god bless 'em) have been working on the problem with a far more massive system for 130+ years. To say it doesn't work there indicates to me you haven't been there...the scale of engineering is truly impressive (an ethos seeming lost in Oz since completion of the Snowy Scheme)

That is not to say they got it 100% right as there have been significant unintended environmental impacts....which are being corrected...and one would think we could learn from their efforts as well as errors.

I don't accept the argument that throwing ones hands up and saying its in the lap of the gods.

Levees, floodways & wing dams can and do work. The Wivenhoe Dam clearly has had a mittigating effect during these recent floods...but more needs to be done

Time to think about things! As you would be aware Brisbane is built on floodplains of a coastal catchment. Given the typical soil type and the topography you are not going to be able to mitigate this area as there are far too many sub catchments and tributary streams that contribute to the Brisbane River, take for example Kalangour area – they had a raging 4m flood come through on the Tuesday when Brisbane did not. It’s all to do with the topography and the slope and the rainfall intensity and duration within the catchment areas. There are no real clear cut remedies in the majority of cases, except in some rural areas where a buffer zone can be utilised – but this is really subjective and determined by the terrain. The Wivenhoe Dam is mitigating a lot of water, but it is water from high up in the catchment, don’t forget that very heavy rainfall also fell below the Wivenhoe catchment zone and has been contributing to the majority of the flow as well. Everything adds up – and if they all arrive at similar times you end up with inundation that the poor folk are suffering up there now.

For those who like calculations you can determine the Rainfall runoff of the catchment very roughly using Manning’s formulae See here http://www.fao.org/docrep/006/ad083e/AD083e13.htm and this really only works for a few hectares, not huge square kilometres of catchments which of course are now the areas we are now talking about that are outside this level of calculation.

So have a quick tutorial here http://www.uq.edu.au/~e2hchans/civ3140/tut09_2.pdf

You then move onto Floodplain catchments. big picture stuff! But one thing to remember is that the ground was supersaturated to start with - so your Manning’s coefficient will be more like hardstand surfaced – 100% impervious.

I agree now is not the time for politics – go elsewhere for that. As for engineering remedies, you can only do so much. Without the rainfall time of concentration figures it would be very difficult to estimate outcomes, in some parts of the catchment they would have experienced rainfall that would equate to an event between 1%AEP and 0.5% AEP rather than the 1% AEP in most places that may have been experienced. Most places would have had a 10% AEP or greater – they all add up. http://www.bom.gov.au/hydro/has/rare_text.shtml If you look at the rainfall that Toowoomba experienced – they were well and truly over a 1% AEP and it showed, and they were on very steep slopes >6% for memory they got nearly 80mm rainfall within the hour period, over60mm falling in 30-40minutes. You can’t plan or mitigate for that.

[rat156]

Originally Posted by Peter Ward

Nations need all sorts of structures, but the NBN looks like fairy floss to me given recent events.

So the pollies have to be able to see into the future as well now?

The NBN was planned for years ago, give RECENT events the money could probably be better spent elsewhere, but not at that time...

Get off your high horse Peter, there is no political agenda to be pushed with the floods.

Cheers
Stuart

[iceman (Mike)]

Agree and agree. Time to lock this thread.