Works on Scrivener Dam

AAMC said :

Let’s not forget that these bolts are holding up a few million tonnes of water, work like this is never going to be cheap.

Holding UP a few million tonnes? How did you work that one out?
The calculation to rough estimates is relatively simple. Height of the water head over relative area of the doors. It would absolutely nowhere near millions of tonnes and would be lucky to be within hundreds.

creative_canberran said :

To service the dam gates according to the technical specs for the dam, a specialist “service gate” is floated to behind the gate requiring work. Ballast tanks are flooded, sinking the special gate and placing it against the wall and the lake bed to create a seal. The fish belly flap is then open and water emptied. Still not sure where the lowering of the total lake level comes into this?

Could it be that each time they empty the big chunk of water between the dam and the “special gate”, there is a correspondingly smaller amount of water remaining in the dam?

It is also possible that the “special gate” does not form a perfect seal when sunk, and that while it is in place there is a constant leaking of water…

Some more news about the lake levels and a sudden increase in dead carp around the foreshores which the NCA is claiming not to be linked to the water levels: http://www.abc.net.au/news/2011-12-08/low-lake-levels-described-as-safety-concern/3720702

To service the dam gates according to the technical specs for the dam, a specialist “service gate” is floated to behind the gate requiring work. Ballast tanks are flooded, sinking the special gate and placing it against the wall and the lake bed to create a seal. The fish belly flap is then open and water emptied. Still not sure where the lowering of the total lake level comes into this?

Classified said :

johnboy said :

shirty_bear said :

Heard talk on the wireless that the lake level will need to be lowered. Not clear how far, but “drained” was not the word used. Would be an interesting (if unsightly) exercise.

500mm, half a metre.

So which is it?

I live in a part of the universe where the laws of physics still require that 500mm equals half a metre, so I’m not currently having any problems with this clarification.

creative_canberran said :

Lowering the lake level is the most suspicious part of this whole thing. I’ve actually read the master technical documents for scrivener dam, they go into remarkable detail about every aspect of the dam’s design, operation and maintenance. Everything from how to enter the water tight gallery and use the internal communications and “dead man” system to how to fit the temporary service gate to allow for repairs to the fish belly flaps. documents I’m waiting on.

Lacking any further context, I can only say that that is one of the weirdest things I’ve ever heard of. I’m hoping against hope that you’re a civil engineer with a pressing need to read dam construction documents…:-)

dungfungus said :

AAMC said :

Let’s not forget that these bolts are holding up a few million tonnes of water, work like this is never going to be cheap. I would love to see them drain the lake for the works, then we could see all of the hidden “treasures” and clear them out.

Maybe the missing Ruger .22 will be found?

There’s be lots of very interesting things to be found, for sure. Lots of crap, too.

dungfungus said :

AAMC said :

Let’s not forget that these bolts are holding up a few million tonnes of water, work like this is never going to be cheap. I would love to see them drain the lake for the works, then we could see all of the hidden “treasures” and clear them out.

Maybe the missing Ruger .22 will be found?

I think i need more context dungfungus, i don’t get it.

Lowering the lake level is the most suspicious part of this whole thing. I’ve actually read the master technical documents for scrivener dam, they go into remarkable detail about every aspect of the dam’s design, operation and maintenance. Everything from how to enter the water tight gallery and use the internal communications and “dead man” system to how to fit the temporary service gate to allow for repairs to the fish belly flaps. Given what I know, there doesn’t seem to be any reason to lower the level, except to reduce the pressure on the dam and gates.

On a side note, this isn’t an isolated incident for a dam in the ACT. I’ll be posting something more comprehensive though about that when the National Archives has checked and released some documents I’m waiting on.

AAMC said :

Let’s not forget that these bolts are holding up a few million tonnes of water, work like this is never going to be cheap. I would love to see them drain the lake for the works, then we could see all of the hidden “treasures” and clear them out.

Maybe the missing Ruger .22 will be found?

dpm said :

Yikes!! Let’s see…. if we reserved $5M to buy the 120 bolts and to pay for associated replacement of encasing ‘steel and concrete structures’, the remainder of that $20M figure could employ 120 people (each at a rate of $125,000) to replace one bolt each! Maybe they should get a second quote? 😉

Better still, I am sure the community minded Bunnings would supply the necessary Made in China nuts and bolts at a good discount (provided single units are not required) and the local Lions Clubs could organize a weekend working bee to knock the job over. ABC 666 could organise an OB and Pedal Power could run a sausage sizzle there to raise money for the Bowen Drive freeway. It could be a real fun event. Would save millions.
I wonder how the bolts were sabotaged by extremists who hate dams – has the security video been checked to see if a couple of people with brush cutters were in the vicinity on a certain date?