ACTEW Water has posted a series of pictures as the new Cotter Dam fills up and the old dam wall disappears beneath the waters:
The original dam was built in 1915, and the reliable river it is built on, the Cotter, was instrumental in the decision to place the National Capital where it is today.
The height of the dam was increased in the 1950’s to around 30m high, with a capacity of just under 4 gigalitres (billion litres).
The new Cotter Dam is being built 100m downstream of its predecessor and at 80m high towers above it, capable storing much more water at 78 gigalitres.
It is not possible to view the old dam as it is within the Enlarged Cotter Dam construction site, however we will continue to keep our customers updated with photos as our faithful old friend is gradually submerged.
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What’s Your opinion?
Old Cotter Dam hears the mermaids singing
bundah said :
Very lame attempt at humour.
Keijidosha said :
Ignorance because you obviously haven’t gone any further than Canberra Times headlines, or else you would know the detailed studies behind the decisions and wouldn’t dismiss the new dam so flippantly.
There’s three catchments that have always been identified for the ACT: Cotter, Queanbeyan, South ACT (Murrumbidgee, Nass, etc)
Cotter is very large, has the best raw water quality, and has existing supply infrastructure (bulk mains, treatment, pumping, etc)
Queanbeyan is larger, but there’s a demonstrated rain shadow, agricultural use demands higher level of treatment and the water has to be pumped.
South ACT potentially offered the greatest potential to increase supply, but would have required extensive new infrastructure, raw water quality would have been poor and required extensive treatment, and the infrastructure and environmental aspects were always problematic.
The enlarged Cotter Dam greatly increases storages and sources high quality raw inflows. It uses existing infrastructure. It replaces an ageing dam and being at the end of the chain of dams, offers some redundancy as Corin and Bendora age (both of which have already had structural issues identified).
Bendora and Corin remain the primary water storages from which most water will be drawn even after the new dam is commissioned, and Googong remains the main secondary storage.
The new Cotter Dam will only be drawn on when storages or other circumstances demand it as a last resort. It has a design life far in excess of the Tennant Dam with far lower environmental and infrastructure issues than Tennant.
So you have a project that kept upfront costs competitive with other options and will add little if anything to ongoing supply costs.
c_c™ said :
Behind the door when they were handing out humour?
c_c™ said :
Ignorance of what exactly?
Didn’t the original dam/pumps use a Pelton wheel pump? Surely that was a good idea at the time.
Keijidosha said :
But that’s where the catchment is and the consumers are where they are.
It’d be nice to be spoiled for choice but I think the idea is that we’ll take any and every catchment we can get at this stage. We only need to pump it if we need it.
I do not think they will sing to me.
Keijidosha said :
Pure ignorance.
c_c™ said :
The new Cotter Dam continues the worst legacy of the old dam – being built in a location that requires pumping to supply Canberra. So not only did it cost a mint to build, the ongoing costs just to access the water are steep.
bundah said :
If you don’t know what you’re talking about, don’t post.
johnboy said :
That’s the least of it.
Solidarity said :
Nothing except it’s 2013 and we’re much thirstier these days,besides it’s better to have more than less!
http://www.actewagl.com.au/Environment/Water-statistics-and-weather/Dam-levels.aspx
So when will this be updated to reflect the new capacity?
it was about a third of the size needed?
What was wrong with the old one? (i’m genuinely curious)
What is it about people who write media releases, they’re invariably incompetent.
It wasn’t ‘built in 1915’, even if that year were significant it’s the wrong language. It was built 1912-1916, and the release should read ‘completed in 1916’.
As sad as it is to see the old dam go under, it’s interesting to consider that it was probably the biggest public works mistake in ACT history. Everything about it was flawed, and yet it did a decent job for decades and still stands over a century later. For all the bleating about the new dam being expensive and delayed, in context, I think history will prove it a good project that corrects the mistake that was the original dam.