Meanwhile back in Oz, Robert says engineers assure us that

desalination is environmentally acceptable and a cheaper option than stormwater recycling or rainwater tanks.

With great respect, Robert, I’d like to hear from marine biologists as well. It may be that the Melbourne project is OK environmentally, but I haven’t heard anything authoritative about the environmental acceptability of the one we are building at Tugun on the Gold Coast. I worry about the currents sweeping the salt northwards. Recently they found the body of a drowned swimmer 40k further north.

That’s entirely reasonable to worry about. However, as I understand it standard computational fluid dynamics techniques can be used to model the dispersal of the salt, given decent models of the typical currents. If it’s a problem, you need to build more widely dispersed outfalls. Yes, you’d want to consult marine biologists as well.

At some point, of course, the cost of making sure the brine doesn’t pose a significant environmental problem could potentially exceed that of rainwater tanks, but frankly that strikes me as unlikely given just how expensive retrofitting rainwater tanks is.

But the wider point that this is a system that you can model before you can construct it to be pretty sure that it’s not a problem.

there are not many major dam projects out there anymore.

Apart from the Grand Inga, that is.

this giant dam will cost $80 billion to build and will have twice the installed generating capacity of the current record-holder, the Three Gorges Dam in China. Grand Inga would produce enough electricity to serve all of the more than 500 million Africans who currently go without.

Wikipedia tells us that the Grand Inga is part of a series of Inga dams , albeit the biggest by far.

Meanwhile back in Oz, Robert says engineers assure us that

desalination is environmentally acceptable and a cheaper option than stormwater recycling or rainwater tanks.

With great respect, Robert, I’d like to hear from marine biologists as well. It may be that the Melbourne project is OK environmentally, but I haven’t heard anything authoritative about the environmental acceptability of the one we are building at Tugun on the Gold Coast. I worry about the currents sweeping the salt northwards. Recently they found the body of a drowned swimmer 40k further north.

Given my worries about desalination, the lack of suitable dam sites and the unwillingness of the people of Northern NSW to give us their water from the Clarence, my support for rainwater tanks is based on the fact that it seems the only major untapped source. So it relates to our particular circumstances.

Alternatively we could send some of the ‘Mexican’ invaders back south.

Robert, surely you have forgotten the other bullet in your nutshell summary. Dams.

Large scale dams are always and environmental trade off and inefficient as water saving mechanisms (because of the large amount of evaporation and loss of water getting to and from the dams). In times of water shortages the Shoalhaven River is harvested by pipeline to top up Sydney dams but it is estimated that as much as 60% of this water is lost before it gets to the consumers tap. So in the drought the Shoalhaven was badly stressed to get just 40% of the water taken from it to Sydites so they didn’t have to go to Stage 4 restrictions and the North Shore could continue to have full swimming pools and exotic green gardens. (Surveys showed the greatest individual users of water during the drought have been the wealthy Sydney suburbs.)

Apart from the 3 Gorges dam (which is already creating a desert and has changed many other environments up and down stream, mostly for the worse), there are not many major dam projects out there anymore. Even the US who had a preponderance to dam everything above a trickle have mostly stopped building dams. Even large scale farm dams (and especially the massive schemes like Cubby’s) cause micro environmental changes around them and lose much to evaporation.

Beattie’s dam plan is asking for yet another future environmental disaster that another generation will have to pay for.

Recycling and storm water harvesting are definitely the go, especially where in places like Sydney there are large underground areas to store the water.

But seriously: If policy makers got the market for water right — allowing trade from rural to urban areas and charging the ‘right’ price for water — we’ be much better off. To get people on board, this could include a right for every person to 75ML a year for free, then pay full (long run marginal) cost after that.

Of course, there would still be a role for Govt, such as providing natural monopoly infrastructure like big pipelines. However, mandating rainwater tanks and grey water systems is almost certainly bad policy. Too expensive for too little water. And if it is justifiable, people will do it themselves if prices are right. Market failures such as information or capital constraints can be addressed if it benefits outweigh costs.

And let’s not forget the environment. Here’s a link to a discussion I had with Possum Commitatus on the Murray Darling plan and better ways to secure environmental flow for the river system.

Less than 200 hectares out of ~57 000 hectares in the Thomson are logged every year - and the modelled water yield is increasing every year.

And the licences will cost a lot more than $3.9M to buy out.

The real threat, that dwarfs any logging impacts (perceived or actual) is a large bushfire. Which is inevitable.

Bernice, might I suggest that sometimes engineers know what they’re talking about when it comes to engineering problems. When they say that desalination is environmentally acceptable and a cheaper option than stormwater recycling or rainwater tanks, it’s possibly because it’s environmentally acceptable and a cheaper option than stormwater recycling or rainwater tanks. I’d prefer to spend the money on solving other problems. We’d probably save a couple of billion dollars in Victoria alone doing it this way; that’s a couple of billlion dollars that could be spend shutting down coal-fired power stations.

If you want to teach people lessons, buy television ads. It’s a lot cheaper.

(I’m willing to bet even more that I won’t be alive to collect.)

Robert, Brisbane has taken a three-fold approach. Recycling, desalination and more dams. I think it’s not going to rain as much here either. If I were Beattie I’d be planning a second desal plant.

I know rainwater tanks are an expensive way to go, but the water is there. The Brisbane City Council will only subsidise them now if they are plumbed into the house, and have increased the subsidy to make that easier.

I’m surprised that some commenters don’t want potable water in the bathroom basin.

If irrigators want to learn the bloody value of water, they can pay urban consumer prices for it…

hear hear. (or is that here here)
And I’d send ‘em a bill for the last 50 years worth too.

I grew up with tanks and dams. Plenty in winter when you don’t need it. Fuck all in summer when you do. (Did I tell you about the time my pet cocky drowned in the house tank? …well……)

I’d be willing to bet $100 at about evens that we’ll see a few floods like Gippsland today in catchment areas and that within 3 years we will have 100% full catchment.

I had a good laugh at the cartoon in The Age today: [link]

I agree that each household should have at a minimum a rainwater tank, and greywater recycling (to power the loo and water the gardens). The mains water should only be used for drinking/cooking water.

Considering the Thomson catchment, which supplies over 50% of Melbourne’s water during drought years:

Over 50% of the Thomson catchment has now been logged.
The area most heavily logged produces 70% of the water.
This is causing the loss of 20 gigalitres of water each year from the catchment, which amounts to the water used by about 100,000 households.

The value of the water lost subsequent to logging far exceeds the low value of the woodchips, timber and royalties. Victorians would be $147m better off per year if logging of catchments stopped.

Melbourne Water should buy out the timber licenses for the Thomson and Yarra tributary catchments at an estimated cost of $3.9 million, rather than spend the estimated $20 million to bring the Tarago catchment back into the domestic water supply system.

If the Bracks government were to stop logging our native forest, adopt further conservation measures and encourage every household to use a water tank, we may not even need the $4 billion desalination plant which will double the cost of water bills.

The UK Stern Report estimates that deforestation represents more than 18% of global carbon emissions, so protecting protecting our forests from logging has the added benefit of ensuring the carbon they store stays there and does not further contribute to climate change.

So why does Steve Bracks keep logging our water catchments?