Awoonga brain teaser

[BigChiefBarra]

Any intellectuals out there feel like calculating how much more rain the catchment needs to send Awoonga over the top

Im certainly not smart enough !!! Would be an interesting fact though..

Gaz

(I certainly don't see that as a possibility at present - she is a HUGE expanse to fill)

[tossie]

Lots.

Cheers Shaun

[Dick Pasfield]

Any intellectuals out there feel like calculating how much more rain the catchment needs to send Awoonga over the top

Im certainly not smart enough !!! Would be an interesting fact though..

Gaz

(I certainly don't see that as a possibility at present - she is a HUGE expanse to fill)

Track back to where the lake started to rise (found a QLD website that shows Awoonga stream rises yesterday).

Track back to when the rain started (BOM site)


Find all your gauging stations in the catchment

Lay the data side by side i.e. daily rainfall compared to daily lake rises (there will be a delay)

Convert the rise to gigs for better accuracy (should be a website that can give that info?) or if not just leave it as a height measurement and add a 'fudge' factor.

Work out what's left to go and there you go It'd be near enough considering all the variations of rainfall etc you have to deal with.

[Chris_2184]

rainfall intesity would play a big part in the actual catchment run-off so it would be pretty difficult estimating how much more rain we need to fill it, 500mm falling in 2 days would increase levels a lot more than 500mm over 2 weeks as an example.....just my thoughts

Chris.

[gladbream]

150mm and we'll go close. may need some help to catch the barra as they come over

[tossie]

Kurt, do you really think another 6 inches is enough I am no maths genius but sceptical on that amount. Would be an awsome sight though If you need help just sing out.

Cheers Shaun

[gladbream]

150mm is a heap of rain. remember there is already current inflows and the surface is charged. we arent working on what falls on water commmon sense tells its a big catchment. trust me on the next 150mm it will go. guess who's job it is to scoop the dead barra from the other side of the wall............ yep it sucks, all of that work gone to a 42m death drop...

kh

[BigChiefBarra]

Quick get very large net

[STUIE63]

150mm is a heap of rain. remember there is already current inflows and the surface is charged. we arent working on what falls on water commmon sense tells its a big catchment. trust me on the next 150mm it will go. guess who's job it is to scoop the dead barra from the other side of the wall............ yep it sucks, all of that work gone to a 42m death drop...

kh

they've got a big net that is strung in front of the spillway at Tinaroo to make the barra turn back so maybe they need one of these for Awoonga
Stuie

[NAGG]

It think would be pretty difficult to calculate out ( unlike rain falling on a flat tin roof) ...... Too many factors , Did the rain fall over the entire catchment , rain intensity , time frame ....... & I guess with now such a large surface area of water ..... it would go up quicker.

But if someone can calculate the theoretical rainfall required - it would be interesting

Chris

[Dick Pasfield]

Given the catchment is 2240sqkms

Current capacity is 76% off full (being 777 gigs)

on the assumption that 75% of rain will actually get into the catchment, the rest evaporated or gone to groundwater (a guess only)

about 104 mm of rain needs to fall equally across the whole catchment to fill the dam.

[Chris_2184]

Given the catchment is 2240sqkms

Current capacity is 76% off full (being 777 gigs)

on the assumption that 75% of rain will actually get into the catchment, the rest evaporated or gone to groundwater (a guess only)

about 104 mm of rain needs to fall equally across the whole catchment to fill the dam.

I think you'll find we'll need a lot more than 104mm of rain for it to go over.

Take a look at the website http://www.gawb.qld.gov.au/damlevels.html

As you can see the recent rainfall event of approximately 350mm fell at the dam (possibly more over other parts of the catchment), this brought the levels up about 26-28% to a current level of 76% full.

Obviously the soil moisture content in the catchment area at the moment would be high therefore there should be more surface water run-off if the same rain event was to occur again.
However, the real pending factor here is rainfall intesity. Going by the website, the main reason so much run-off occured was due to approximetly 300mm falling in two days.
Therefore, if the levels need to rise another 25% we'd need another high intensity rainfall event similar to the previous one, IMO the chances of this happening is faily slim.


Am I wrong?


Chris.

[gladbream]

chris...
talking to the water scientist today and she said 6 to 8 inches will do the job. the rise wasnt due to the sudden dump so much, it was due to the soaks that it copped during the weeks before hand. the joint was like concrete beforehand (as they say = like a cow pissing on a flat rock). well all dams over flow through intense rainfall periods, but still bear in mind that the dam is discharging a heap of water every day for the GAWB environmental flow compliances. im with her. 6-8 inches and she is gone. lets see what happens this weekend. i staying out of this discussion, i'll watch from here in.


cheers
kh

[Dick Pasfield]

I think you'll find we'll need a lot more than 104mm of rain for it to go over.

Take a look at the website http://www.gawb.qld.gov.au/damlevels.html

As you can see the recent rainfall event of approximately 350mm fell at the dam (possibly more over other parts of the catchment), this brought the levels up about 26-28% to a current level of 76% full.

Obviously the soil moisture content in the catchment area at the moment would be high therefore there should be more surface water run-off if the same rain event was to occur again.
However, the real pending factor here is rainfall intesity. Going by the website, the main reason so much run-off occured was due to approximetly 300mm falling in two days.
Therefore, if the levels need to rise another 25% we'd need another high intensity rainfall event similar to the previous one, IMO the chances of this happening is faily slim.


Am I wrong?


Chris.

Maybe

http://agnet.com.au/wpreaus.html