The breathtaking stupidity of the ALP in persisting with a plan to dam the Mary River has to be stopped. Premier Anne Bligh and her mates have to be brought from their parallel universe back to reality. Damming the Mary is an expensive waste of money that won’t solve Brisbane’s drinking water problems.

Illustration: Alex Mankiewicz

We’ve been plastered with glossy brochures, newspaper advertisements, emotive statements made by politicians in parliament and promises that they will ‘drought proof’ southeast Queensland. You would be tempted to believe that the Government had done their homework and that dam building on the Mary River makes economic, environmental and social sense.

The State Government has in fact been mixing fact with fiction, to the point where they now live in a fantasy world of their own making; you could call it ‘Anna in Wonderland’.

If you believe in Anna’s Wonderland you’d see the Mary Valley as well suited for a dam.  In this wonderland a torrential river winds through steep hills and gorges.  Actually, the river is regularly about knee deep.  The valley does not rest on hard rock but the soft sandy sediments and clay of an alluvial flood plain with low, rolling hills. If ever flooded by building a wall 25 metres above ground level and 1.5 km long, the dam would only be five-metres deep on average, creating a gigantic swamp that will evaporate and seep a loss of over 2.5 meters every year.

Anna’s Wonderland story is believed by some very unprofessional and irresponsible members of the Queensland Government.  The Great Sandy Strait is home to migratory birds and all sorts of endangered species such as dugongs, turtles, dolphins and migrating breeding whales. The area is vital for commercial and recreational fisheries and the tourism value is around $440 million a year. Yet, an Environmental Impact Statement (EIS) — done on behalf of Queensland Water Infrastructure Pty Ltd (QWI) for the Queensland Government, stated that there would be no impact downstream of the dam wall.

The EIS speaks of abundant flows downstream.  After extracting 70,000 ML of water a year for Brisbane, they insist that there is enough to protect Fraser Island and the internationally significant wetlands of the Great Sandy Strait.  Yet modelling by the Mary River Catchment Coordinating Committee shows that the flow would be cut to less than a quarter of the natural state if the dam had operated in 2006/2007.  Presently, farmers have not accessed their full allocations of water in three of the last six years and in fact, the last decade has seen flows in the Mary River down to about half of what was previously considered normal. This is a similar trend to what is occurring in the Murray River system.

So serious are the implications of this project, that Federal Environment Minister Peter Garrett will be making the decision about the future of the proposed dam.  He will be considering the fate of the Mary River turtle, unique in the world for having gills in its tail and found only in this river; the Australian Lungfish which breathes the same way as humans do; the Mary River cod and diverse species of  frogs, insects and plants, among them 18 threatened species that need more  habitat, not less, if they are to survive well into the future.

The EIS proposes some unique and comical mitigation plans to preserve the species in the river.  Fish Ladders, a lift that elevates fish up and over the wall, are responsible for crushing and mutilating turtles in the moving parts of the device.  The Paradise Dam on the Burnett River near Bundaberg, has never operated its ladder since the dam was built, breaching the conditions in which that dam was approved by the Federal Government.  As for “catch-and-carry” turtle ramps, where people actually catch the turtles and help them use the ramp, the idea is untested and frankly, would only work in a Hannah Barbera cartoon.

In Anna’s Wonderland, you can have your swampy dams and no methane too.  This is despite research showing that dams are serious emitters of methane gas which is up to 75 times more potent than carbon over a 20-year period.  The Traveston Crossing Dam would be a manufacturer of methane gas and other nasties including methyl mercury which would remain in the food chain.   Aquatic weeds such as Water Hyacinth, Salvinia and others, will thrive, which are already proven to be unmanageable in the Mary and nearby Lake MacDonald.

In Anna’s Wonderland farmland is unlimited and unthreatened.  Our current knowledge about the impact of dams and weirs and rising salt destroying vast regions of the Murray River system is being ignored.  The Mary River is identified as a high priority area for salinity risk.  At a time when the fuel cost of getting food to markets is rapidly increasing, damming the Mary will shatter the productivity of a Sunshine Coast food bowl that supplies milk, beef, fruit, tropical and temperate crops and sugar.

As for water yield, stage 1 of the proposed Traveston Crossing Dam would, at best, supply less than 10 per cent of southeast Queensland’s future water needs. It would be half the size of the North Pine Dam, at a forecast cost exceeding $1.7 billion, with half a billion already spent.  During times of extended drought, the proposed Traveston Crossing Dam would be at dead storage level at least 24 months before the Somerset/Wivenhoe system.

In this wonderland, infrastructure is cost-free, carbon-neutral and water flows uphill.  There is no way in the known universe that Brisbane’s water supply can be sustainable if the proposed Traveston Crossing Dam is part of it.  If the Bligh Government suggests otherwise, they are asking us to believe in fairy tales.  Let’s not “Murray the Mary”.

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