I Have a dirty question

[Mrs Ronnie H]

Hi all
Not what you all may think so get your minds out of the gutter???

On an environmental side what is going to happen in the bay with all the water, silt and debris that is flowing into it. ?????

Apart from the boats, pontoons, tanks, containers floating down the river imagine the amount of dirt and contaminates in the water. Boats hold fuel and oil and who knows whats in those containers.

Surely there is going to be a huge impact on the Moreton Bay area as well as other areas up the coast.

With all the rain I look out the front here and see nothing but brown murky water and the Caboolture River is the same. Fishing is a thing of the past at present and I am thinking will be significantly affected for a long time yet.

What are your thoughts on the state of our coast and how long is it going to take to recover.

Thnx
Ronnie

[Luc]

Oh yea of little faith, don't you know that the green zones will protect the environment.

The bay will recover faster than the flooded lands and in the long run will benefit from the inflow of nutrients.

Floods mean good fishing after.

Luc

[Spot82]

If you check the Offshore reports and my thread in there, have been getting heaps of huge muddies in water that is so fresh you can drink it in the middle of Hervey Bay...

All the debris will make new habitats for fish life and if you can find that isolated shipping container or boat then in a few months it will be loaded with fish!!

The little amount of contaminants compared to the huge volume of water won't have too much of an effect I don't think, the silt might on the other hand.

Anthony

[Horse]

It will all be good in the long run but the inshore areas will be hurt for a while. The amount of sediment being deposited will do some damage but the inshore reefs should recover and as Anthony said there might be a few new honey holes for those lucky enough to find them.

[randell]

mostly FRESH WATER with a few cows, barges, trees, wheelie bins

[tunaticer]

To some it is debris, to others it could well be berley.
Don't worry about the crap going out into the bay, nature heals itself faster than we can imagine.
It is jewie time in the next few weeks.......

[sleepygreg]

This is why most of the 'flood plains' are perfect agricultural land.....its natures way of fertilizing. The amount of impurities is minicule in terms of the volume of water. 'Man' just happened to put dwellings in the way - you can't blame nature for our own arrogance/ignorance.

There is an old saying that relates to fishing....."drought on land, drought in sea.....flood on land, flood in sea".

In the medium term (relatively speaking), this will have a VERY positive impact on the fish stocks and availablity in SEQ.

[Mick]

This is why most of the 'flood plains' are perfect agricultural land.....its natures way of fertilizing. The amount of impurities is minicule in terms of the volume of water. 'Man' just happened to put dwellings in the way - you can't blame nature for our own arrogance/ignorance.

There is an old saying that relates to fishing....."drought on land, drought in sea.....flood on land, flood in sea".

In the medium term (relatively speaking), this will have a VERY positive impact on the fish stocks and availablity in SEQ.

Perfectly said

On another note or maybe on the flip side, I think the Town Planners and Architechs of the south east should immediately make the necessary changes in infrustructure, to model Brisbane and surrounding areas as a Tropical city that is subject to monsoonal rains.
Two 1/100 year floods in 36 years plus global warming, not to mention that this is only the beginning of our wet season with half a dozen predicted cyclones still to come should warrant the seriousness of this matter.
I think it was only last summer Ferny Grove and the Gap were declared natural disater zones after a storm as well??

[oldboot]

Apart from the relativly short term inconvienience to us humans, this can not be a bad thing.

I've read some of the accounts of the floods going back to white settlement and the fishing and marine vigour improves considerably after these floods.

This huge flush pulls all the crap out of the rivers and they come back real well.

Most of that crap gets diluted and carried out out sea, so it is far less damaging than iff it dribbled out far more concentrated with small rains.

remember too that heaps of the floating rubbish gets left behind in the suburbs as the water receeds...tonnes and tonnes of it.

One of my relatives reconed all sorts of fish started comming back into the river after the 74 floods....prior to that the brisbane river was a disgusting place with all sort being dumped into it untreated.

Remember too that the rivers do not end in the bay.....the flow continues out thru the openings and bars...so for good or bad it does not all stay in the bay.

I reconn it will all start with more and bigger yabby and worm banks.

Sorry about seeming so cheerfull about all this ...... but it is a normal natural event.....its mostly us humans that aren't properly adapted to this sort of thing.

Remember too that lots of those creek and river places that ya might have been a bit sus about eating fish from will probaly be welll scoured and clean after all this.

OH yeh I recon the crabs will go nuts.

Think on this.....you are a crab family and someone dumps a whole cow in your front yard.....hey hey... party at jo crabs place for the next week.

cheers

[Axl]

Apart from the relativly short term inconvienience to us humans, this can not be a bad thing.

I've read some of the accounts of the floods going back to white settlement and the fishing and marine vigour improves considerably after these floods.

This huge flush pulls all the crap out of the rivers and they come back real well.

Most of that crap gets diluted and carried out out sea, so it is far less damaging than iff it dribbled out far more concentrated with small rains.

remember too that heaps of the floating rubbish gets left behind in the suburbs as the water receeds...tonnes and tonnes of it.

One of my relatives reconed all sorts of fish started comming back into the river after the 74 floods....prior to that the brisbane river was a disgusting place with all sort being dumped into it untreated.


Remember too that the rivers do not end in the bay.....the flow continues out thru the openings and bars...so for good or bad it does not all stay in the bay.

I reconn it will all start with more and bigger yabby and worm banks.

Sorry about seeming so cheerfull about all this ...... but it is a normal natural event.....its mostly us humans that aren't properly adapted to this sort of thing.

Remember too that lots of those creek and river places that ya might have been a bit sus about eating fish from will probaly be welll scoured and clean after all this.

OH yeh I recon the crabs will go nuts.

Think on this.....you are a crab family and someone dumps a whole cow in your front yard.....hey hey... party at jo crabs place for the next week.

cheers

Well said oldboot I reckon that answers the question perfectly.

[Spot82]

Perfectly said

On another note or maybe on the flip side, I think the Town Planners and Architechs of the south east should immediately make the necessary changes in infrustructure, to model Brisbane and surrounding areas as a Tropical city that is subject to monsoonal rains.
Two 1/100 year floods in 36 years plus global warming, not to mention that this is only the beginning of our wet season with half a dozen predicted cyclones still to come should warrant the seriousness of this matter.
I think it was only last summer Ferny Grove and the Gap were declared natural disater zones after a storm as well??

I think you mean Hydraulic Engineers who look after stormwater management and modelling, town planners have very little to do with the hydraulic aspect of development. Even then if you modelled stormwater drainage on event like T'ba with 8 inches in an hour, the cost and size of the infrastructure would make it impossible to implement.

Most of the houses in brisbane that would have been affected should have been built prior to planning legislation that has been in effect for in excess of 10 years as flood modelling since then has been fairly accurate. Houses built recently should have been 1.3m above the flood peak since you have to build floor levels 300mm above Q100 flood level and the recent flood was 1.0m below this level....

In addition they should have had a lot less water in wivenhoe to begin with, it's main purpose is for flood mitigation not water storage! I thought that wivenhoe's maximum capacity for storage was meant to be around 50% with the other 50% to be used in peak rain periods for flood mitigation?? Who ever was in charge of releasing water is the one who should cop a ear bashing. We have had a lot of rain over the past months, and with decent long term forecasting in place releasing of a fair volume of water should have been happening weeks ago. The old story too little too late...

[oldboot]

Um wyvenhoe has had its walls increased in height recently and it does have 100% more capacity over its stated 100% storage capacity before it goes over the spilway.

They have not let the water get over the spillyway during this event.......iff you ever hear of the spillway running with the flood gates open up at Wyvenhoe........get up a hill...and not a small one.

remember there are 3 main rivers that feed into the brisbane.

The Stanley river that has Sommereset dam only a couple of KM up stream from wyvenhoe....a piddly little dam in comparison and one that made no difference in 74.

The upper Brisbane that joins in above the Wyvenho dam.

All of that would have been under control of wyvenhoe.....and they had all 5 flood gates open for nearly a week prior to the peak, and they had been letting water out of it for weeks prior.

Then there is the Bremmer River that joins several KM below Wyvenhoe and well below The Mt crosby weir..... Colledges crossing is still above the bremmer Junction

I don't know the relative amounts between what has been allowed out of Wyvenhoe and what has been comming out of the Bremmer...... But when you have a 20m ( that is 60 feet arround 6 or 7 stories) pluss flood height at Ipswich ( the bremmer flows right thru the middle of ipswich)......that is a massive amount of water comming out of the Bremmer.......the Bremmer flow is completly uncontrolled

Remember the Brisbane river is under normal dry season conditions tidal and sometimes salty.......all the way up to the MT crosby weir.......meaning the the normal river level is nearly flat and more or less at sea level all the way to Mt Crosby

That puts a different perspective on it.

Normal highest astronomical tide at the brisbane bar ( that is in the port) is arround 2.4 meters.....there has been a flood tide level of arround 5 meters there.
Remember 20 Meters pluss at ipswich....that is a $H#t load of water.

As for the inflows.......they tell us that the inflows into wyvenhoe to this point have been twice that of 1974.

If we did not have Wyvenhoe doing its job the water running thru brisbane would have been much worse...2 maybee 3 meters higher than we have seen

We have got off pretty lightly......there has also been quite a lot of work done on small local creeks too.......so the water has been getting away much better than in 74.......there was lots of minor flooding prior to the main peak in 74.....lots of that would have got away before hand this time.

I got a mate in a shed right next to a creek at Coppers plains...I mean right next to a creek.........that would have had at least a meter thu it in 74.....All the electrical wiring in that shed is over 2 meters off the ground.....he is high and dry this time....thanks to drainage.

I recon we got away with this pretty lightly.

One problem is that people thaught the 74 flood was the once in 100 year flood.........it wasnt.

cheers

[Ben D]

We were lucky it stopped raining when it did, or else the engineers I talked to said there was a chance that wivenhoe could have been overtopped if it had rained for another 6 hours at that rate. But theres a long way to go yet before this years wet season is over.

What people forget is that the large amount of development and agriculture in the catchment today greatly exceeds that which was around in 74, this means there is a lot more silt and mud and other contaminants around than previously. And its not like the productivity of places like Moreton Bay are nutrient limited anymore. Yes, in the past the extra nutrients and relatively small amounts of silt and mud benefited inshore fisheries in the years to come. However, today we already have excess nutrients, as shown by the recent Lyngbya blooms etc, (no lyngbya blooms prior to 74...) so its a different story. If we get improved productivity in the bay, it will be a bonus, but the silt load is enormous and given the amount of development now in the catchment, the "baseline" water quality in the bay is such now that it simply will not bounce back like it used to. In reality, we could lose most of the remaining seagrass beds due to excess sedimentation (like occurred in Hervey Bay in the early 90's), but given the relatively poor background water quality nowadays, these might not come back unless we get serious about better catchment management - and for the biogenic reefs (corals/oysters etc.) where we catch our snapper, I hold grave fears - at least those green zones have now been shown up for what they really are......

[GABBA110360]

I don't know the relative amounts between what has been allowed out of Wyvenhoe and what has been comming out of the Bremmer...... But when you have a 20m ( that is 60 feet arround 6 or 7 stories) pluss flood height at Ipswich ( the bremmer flows right thru the middle of ipswich)......that is a massive amount of water comming out of the Bremmer.......the Bremmer flow is completly uncontrolled

Gday guys
i'm new to this forum this is my first post actually go easy on me ok lol.

i live in yamba nsw we are still cut off to the hway to monday probably.
with f-all to do iwas looking at some figures through bordem really.
wyvnhoe dam i think is holding somewhere near 2.2million megalitres at the moment
and one of the measuring stations upriver from grafton at LILLYDALE a couple of days ago was at 19.5 meters and an estimated flow of 1.37 million megaliters a day.
big numbers when at that rate would fill wyvnhoe dam in 48 hours.

just trivia but ya know

glad we are not like brizzy valley

regards
ken

[danners]

We were lucky it stopped raining when it did, or else the engineers I talked to said there was a chance that wivenhoe could have been overtopped if it had rained for another 6 hours at that rate. But theres a long way to go yet before this years wet season is over.

What people forget is that the large amount of development and agriculture in the catchment today greatly exceeds that which was around in 74, this means there is a lot more silt and mud and other contaminants around than previously. And its not like the productivity of places like Moreton Bay are nutrient limited anymore. Yes, in the past the extra nutrients and relatively small amounts of silt and mud benefited inshore fisheries in the years to come. However, today we already have excess nutrients, as shown by the recent Lyngbya blooms etc, (no lyngbya blooms prior to 74...) so its a different story. If we get improved productivity in the bay, it will be a bonus, but the silt load is enormous and given the amount of development now in the catchment, the "baseline" water quality in the bay is such now that it simply will not bounce back like it used to. In reality, we could lose most of the remaining seagrass beds due to excess sedimentation (like occurred in Hervey Bay in the early 90's), but given the relatively poor background water quality nowadays, these might not come back unless we get serious about better catchment management - and for the biogenic reefs (corals/oysters etc.) where we catch our snapper, I hold grave fears - at least those green zones have now been shown up for what they really are......

Hi Ben,

are you able to estimate any sort of time-frame with your professional background of when we might see the fishing recover to some extent in the river and bay?

also, have you got any idea of the impact this kind of inundation will have on the pelagic fishing around moreton bay in the medium term?

completely agree with your last statement, hopefully now the issues of agricultural runoff and sedimentation, and water quality flowing out of our catchments will be seriously addressed instead of being swept under the too hard rug

cheers
Dan