By the end of the recent state election in Queensland, the Labor Party was proposing not one, but five new dams and the the Coalition a whooping eight new dams. The Wyaralong dam is being planned for a catchment just south of Brisbane and west of the Gold Coast in the Beaudesert Shire. Occasional responder at this blog Sylvia Else, has done some research, and claims even desalinated water would be cheaper than water from the Wyaralong Dam:
I’ve been puzzling over the proposed Wyaralong dam. Given the government’s own cost estimates and the estimated yield, and using an interest rate of 7.5% and inflation rate of 3%, I cannot get the cost of the raw, i.e.
unfiltered, water below $1 per kilolitre, even when I assume a life of 100 years for the dam. I don’t know how much it costs to filter water, but Sydney Water charges 46 cents per kilolitre less for unfiltered water, so filtering is presumably reasonably costly.
This appears to mean that bulk filtered water from Wyaralong dam will be more expensive than desalinated water. With Perth’s desalinator capital and running costs, I get a bulk water cost of $1.02 per kilolitre.
It’s true that the only place one can desalinate seawater is on the coast, but it appears that the government’s intention is that all of the water supply systems should be connected together in a network, so desalinated water could be distributed to anywhere that the Wyaralong dam could serve.
So why build the dam? It seems to make no economic sense, even if the wished for rainfall (based on the next 100 years being like the last) appears.
There was a line in the Hitch-Hikers’ Guide to the Galaxy. When asked why it was necessary to build a by-pass over the top of Arthur Dent’s house, the council official’s reply was “What do you mean, why has it got to be built? It’s a by-pass. You’ve got to build by-passes.”
May be that’s the reasoning being used here.