19/06/2007 - 22:00

Water waste at Wellington

19/06/2007 - 22:00


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State Scene remains bamboozled by the failure of successive state governments to tap the Wellington Dam’s huge stock of water.

State Scene remains bamboozled by the failure of successive state governments to tap the Wellington Dam’s huge stock of water.

Wellington Dam, near Collie, holds 186 gigalitres (GL) – nearly two-thirds of Perth’s annual consumption.

And it is relatively close to Perth, much closer than, say, the Kimberley which former Liberal leader Colin Barnett highlighted during last election campaign in his desperate bid to become premier.

Wellington Dam was built in the early 1930s to supply water to Great Southern consumers, who then made up a sizeable portion of Western Australia’s population.

Although bankrolled by federal tax dollars – then pounds – the huge dam was subsequently transferred gratis to the state government.

Its next milestone came in the late 1940s, when its capacity was boosted to meet the needs of nearby irrigation farmers.

Now for the really bad news.

By the 1960s, its salinity level had begun rising due to over-clearing of its once timbered eastern hinterlands. All efforts to combat this have failed to return its water to the initial potable levels.

In the late 1980s, the Harris Dam was built nearby. Situated in woodlands, it remains untainted by salinity and is the source that meets Great Southern requirements.

Another outcome is the need to annually scour the denser saline water at the dam’s lower levels, which involves opening a large gate valve at the base of the dam’s wall to discharge up to 40GL annually into the sea via the Collie River.

Millions of dollars spent over 30 years by several government agencies to counter salinity biologically – land acquisition and tree growing – have failed to make its water potable.

WA’s tragic Wellington Dam story is made more so because at any time it is holding 70 per cent of the total water in Perth’s 13 metropolitan dams.

So here’s this magnificent man-made structure near Perth that’s unusable for drinking purposes.

Let’s, however, continue with this tragic story.

In October 2002, then premier, Geoff Gallop, said: “An extra 15GL of water could be available to Perth and Goldfields residents under an innovative proposal to mix water supplies from two South West dams.

“Under the proposal, up to 15GL of water from Wellington Dam currently affected by salinity would be ‘shandied’ with fresh water from Stirling Dam to produce water of drinkable quality.

“Under the proposal – which is still to receive approval from the Environmental Protection Authority – three parts of Stirling water would be mixed with one part of Wellington water.”

This claim was undoubtedly prompted by WA’s low 2001 and 2002 winter rainfalls.

However, that idea has vanished, just like some of the dam’s water that evaporates each day.

Nearly a year later – September 2003 – Water Corporation chief, Jim Gill, raised desalination, highlighting Australia’s strong dollar, economies of scale, and several other factors that were making the reverse osmosis (RO) desalination method a real option.

But he wasn’t gung-ho.

“Dr Gill said it was unlikely WA would build a desalination plant soon because the estimated lower annual cost of drawing water from the South West Yarragadee aquifer compared to desalination – $10 million opposed to $24 million – made the underground water source more attractive,” one press report said.

“If you look at the trend, RO has been getting cheaper.

“But there is no prize for being the first mover of this technology on this scale.

“Under normal circumstances, it could be a decade, or two or three before we have a RO plant.

“Drawing water from Yarragadee is still the preferred option.”

Well, as at June 2007, we know all that was pie-in-the-sky. Wellington Dam is still untapped and continues to be annually scoured from June to late October, with 40GL of slightly saline water (1,500 parts per million) flowing into the sea.

And now the government plans spending nearly $1 billion to treat seawater (36,000ppm) with an RO desalination plant at Binningup, just 30 kilometres from Wellington Dam.

The more saline the water, the more it costs to desalinate.

The $1 billion Binningup decision comes hard on the heels of the $440 million already spent on a similar RO desalination plant at Kwinana now in operation.

Wellington Dam’s water was to be ‘shandied’, but that never happened. The South West Yarragadee was to be tapped, but that’s not going to happen.

RO desalination plants were said to be up to 30 years away. We now have one at Kwinana and another to follow at Binningup, together costing a cool $1.4 billion. So, backflips galore.

And among all these twists and expensive turns, about a quarter of Wellington Dam’s slightly saline water (up to 40GL) continues to wasted out to sea each year, something that’s been happening for 30 years.

What makes this tragic saga even worse is the fact that a Perth company has proposed what seems a reasonable and farsighted fix.

Rather than wasting this slightly saline 40GL each year, it says, this water could be treated by a RO plant below the dam near Brunswick, using the hydraulic head (pressure) of the water falling 150 meters to sea level.

This downward pressure would replace the need to outlay $20 million for power.

The cost of operating Kwinana’s RO desalination plant will be at least $24 million annually, while the coming Binningup RO plant will cost at least that much.

Agritech Smartwater is the company proposing to tap Wellington Dam’s slightly saline water.

It’s principal, Peter Coyne, has also proposed tapping saline water from across WA’s southern Wheatbelt for desalination and generation of hydo-power. He proposes to do this by construction of a regional de-watering canal network (see State Scene, 'Visionary Coyne worth his salt', March 1 2007) and, in the process, removing salt from the agricultural belt.

Mr Coyne put his Wellington Dam engineering, as opposed to biological, proposal to the government soon after Dr Gallop’s September 2002 never-implemented ‘shandying’ idea was announced. He continues to promote it.

Since then, the government has moved to tap the South West Yarragadee aquifer but has done a U-turn on that idea.

It has also outlaid $440 million on the 45GL, energy guzzling Kwinana RO desalination plant, and intends building another RO energy guzzler at Binningup for nearly $1 billion.

Understandably, opting for both these expensive-to-build and expensive-to-run options baffles Mr Coyne.

“The government’s continued refusal to entertain my Wellington Dam proposal is an affront to the water-using taxpayers of WA for several reasons,” he told State Scene.

“Firstly, the combined expenditure for Kwinana and Binningup ROs is almost $1.5 billion to supply Perth with just 90GL of water annually.

“Secondly, the current cost of Kwinana water to consumers is around $1.30/kilolitre and the forecast cost for Binningup water is $1.80/kilolitre.

“Agritech’s Wellington Dam proposal offered to build, own and operate all infrastructures – so no cost to taxpayers – and deliver annually 45GL of purified water at 65cents/kilolitre.”

“Thirdly, government refuses to produce any meaningful plan for fixing Wellington Dam and its entire eastern hinterland catchment.”

State Scene is surprised Mr Coyne’s plan has not been welcomed.

In parliament on May 17, when opposition leader Paul Omodei highlighted Agritech, the premier, Alan Carpenter, interjected, saying: “In relation to the Wellington Dam option, the Water Corporation will continue to have discussions and investigate with possible proponents.

“I hope the leader of the opposition is not pushing a private business venture here; is he?”

So what if Mr Omodei is attracted to the Coyne plan? Surely one is entitled to back an option that’s far cheaper than the $440 million Kwinana and $1 billion Binningup RO plants.

Had Agritech’s option been adopted three or so years ago, the $440 million Kwinana RO plant wouldn’t have been needed.

However, now that it’s up and running let’s leave that be.

But letting things be shouldn’t mean repeating that move to desalinate seawater at Binningup for more than twice the cost of the previous mistake.

Given WA’s many public needs, including release of more urban land to reverse escalating residential affordability, State Scene needs convincing that this $1 billion couldn’t be better used and Wellington Dam’s slightly saline water purified via the private option.

After all, it’s far cheaper to taxpayers in terms of infrastructure as well as the cost of water.



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