The troubled catchments

On death row

• April 3, 2009

The slow death of the Murray's Lower Lakes catchment has aroused little concern beyond South Australia's borders, but the environmental disaster could also have catastrophic consequences further up the river. Peter Ker reports.

TAKE a barefoot walk across the parched Finniss riverbed and you will be struck by the harsh beauty of the Australian landscape. The cracked riverbed stretches out like a tile mosaic, framed by reeds and rushes.

As you admire the view, the skin on the bottom of your feet will slowly be eaten away and your eyes and throat might become sore.

This is what an environmental catastrophe looks and feels like.

This toxic patch of Australia is about seven hours' drive from Melbourne — closer than the recent oil spill in Queensland, and of more immediate consequence than the proposed pulp mill in Tasmania.

Yet South Australians, reluctant inheritors of this problem, say Victorians are not interested, despite the fact that they are partly to blame.

The Finniss River is one of several reaches of the Murray River's Lower Lakes catchment that has turned acidic.

The two freshwater lakes, Alexandrina and Albert, were formed as the Murray pooled near the coast, summoning force for one final thrust over the dunes and into the sea. The prospect of such a surge into the sea seems unthinkable today as flows reaching the lakes dwindle.

At the south-western corner of the lakes, on a narrow channel opposite Hindmarsh Island, sits the historical town of Goolwa. Goolwa looks a bit like Port Fairy and feels like Sorrento. But these days its channel is drying up, leaving hundreds of metres of sandy lake bed exposed to the sun.

Jetties stand impossibly tall, with no water below to give them meaning or purpose. Yachts sit encrusted in mud.

Luxury homes line Goolwa's Barrage Road, but the nature strip along this winding foreshore drive has a string of "For sale" signs. About 30 per cent of homes in the street are on the market.

Estate agent Kathleen Fry confides that some homes here have sold recently for 20 per cent below their purchase prices several years ago. Showing a saleswoman's optimism, she says it's a good time to buy because prices will shoot back up when authorities find a way to send more water down the Murray and into the lakes.

The bare lakebed around Goolwa poses a bigger threat than turning away tourists and ruining the views of wealthy owners of holiday homes. The composition of soils in the lakebed means a chemical reaction occurs when they are exposed to oxygen. The result is naturally occurring sulphuric acid, like that seen at Finniss River, which can corrode man-made structures, contaminate drinking water and kill organisms.

The CSIRO recently reported that Finniss River and nearby Currency Creek now have a pH level similar to battery acid, and there are fears that more of the lakes could turn acidic.

It's bad news for fish and turtles, and the people of Goolwa are fast discovering that humans are as vulnerable as any other animal when their habitat becomes poisoned. When the winds blow hard, they turn the soils into acid dust, carrying it into eyes, throats and homes.

"The health problems so far have been irritation of the eyes, some irritation of the skin … it causes a sore throat," says former South Australian premier Dean Brown, once the MP for the Goolwa region.

The dust is creating concerns for others — such as people on Hindmarsh Island — who rely on tanks for drinking water. Residents here are advised to hose the dust off their roofs, clean out their tanks and be particularly careful with water gathered from the first rains of the winter.

The impact on people's health is being monitored by the Environment Protection Authority and the SA Health Department.

Phil Shaw lives and grows grapes near the worst of the soils at Currency Creek, and he is concerned for his four children. "When you get a strong northerly or southerly it will whip up a haze, which is picking up some of these acid sulphate soils and carrying them in the air and people are breathing them in," he says. "You can actually smell it, it's a certain smell, so it's got to have some effect."

Preventing the spread of acid soils is as simple as ensuring the lakebed remains covered by water. But at the end of the Murray River, nothing could be less simple than finding spare water.

Plans are being devised to contort the lakes into a series of barriers and weirs, a tactic that will raise water levels where they are needed most. But these measures simply buy time.

South Australia's Minister for Water Security, Karlene Maywald, says the Lower Lakes have entered a 12-month "death row" period. By next February, water levels in the lakes are predicted to fall to 1.5 metres below sea level — a key trigger for acidification. If those projections prove true, the SA Government will reluctantly let in seawater. "But we won't flood the lakes," Maywald says. "We will introduce only enough seawater to maintain a level to prevent acidification."

A weir is likely to be built near where the Murray runs into the lakes, creating a barrier between the salty, potentially acidic water in the lakes and the place where Adelaide draws its drinking water from the Murray. Last financial year, Adelaide relied on the Murray for 91 per cent of its drinking water.

Allowing seawater to take over the lakes seems an easy solution, particularly to those who see the lakes as a place where useful fresh water is simply wasted. But Maywald says the weir and seawater plan is not a permanent solution for two reasons.

Seawater inundation would change the ecology of the lakes, which, along with the nearby Coorong, are deemed to be "wetlands of international significance" under the RAMSAR agreement. They are the biggest RAMSAR site in the southern hemisphere.

Seawater inundation would risk hyper-salinity, or the "Dead Sea effect", and would almost certainly kill most of the vegetation and fish in the lakes.

More importantly, says Maywald, the river will always need to dump a minimum amount of water into the lakes for its own health. She says at least 350 billion litres — and preferably more — must flow from the Murray into the lakes each year to cleanse the river of its salts.

"If you don't have that amount flowing past that (weir) point you will spread a cancer up the river," she says.

Maywald says that's why the fate of the lakes should be of concern to upstream irrigators and states — a river dies from the bottom up. "That is the point that is missed by most irrigators," she says.

But short of heavy rainfall, it's hard to see where extra fresh water is going to come from. Most of the well-documented rescue plans for the river are long-term solutions.

The Commonwealth's buyback of water entitlements and irrigation upgrades will take the best part of a decade to complete. Like the Victorian Government's modernisation of irrigation channels, they will ironically be of greatest benefit in times of high rainfall.

With extra flows unlikely before February, a bigger plan for the lakes is being devised behind the scenes, one that would change them forever. The plan would open Lake Albert — the smaller and less healthy lake — to the saltwater of the Coorong, while closing it to Lake Alexandrina.

Though conceding Albert to a largely saline future, the plan would at least ensure its acid sulphate soils are covered. That would allow Alexandrina to retain all the fresh water flowing from the Murray, spreading supplies less thinly and saving some freshwater ecology.

As they plot radical changes to an internationally listed wetland of immense cultural significance, the South Australians remain bemused at the apparent lack of concern in "upstream" states.

Victorian Water Minister Tim Holding recently criticised South Australia for "prevaricating" on whether to build the barrier weir near Wellington, saying it would save at least 200 billion litres of Murray water lost to evaporation each year.

Logical analysis of that statement would deduce the word "evaporation" can be substituted for "Lower Lakes", but the minister declined to say if he thought seawater inundation was the best solution.

South Australians also wonder why the lakes are not evoking the level of passion in suburban Sydney and Melbourne that the Tasmanian pulp mill does. Dean Brown suspects it is because solving the crisis might require sacrifices in upstream states, while the pulp mill is a cause without consequences for many mainlanders.

"There's no national desire to fix what is a developing national disaster … partly because each state is wanting to hold on to as much water coming down the river as it possibly can," he says.

Brown urges Victorians to lobby their Government to consider the environmental needs of the river, and says Queenslanders should be more concerned about the lakes than the recent oil spill along their coast.

"The disaster unfolding here is frankly many times greater than what occurred with the oil spill," he says.

Some Murray experts privately describe the South Australians as "A-grade whingers", who, like upstream states, could be doing more themselves to improve the situation: they recently bought 60 billion litres on the water market but gave it to irrigators instead of the lakes; they have built new pipes taking water from the river to vineyards such as Phil Shaw's; and Adelaide was the slowest mainland capital to opt for desalination.

But Maywald is unrepentant, pointing out that SA irrigators are already given lower extraction rights than farmers in Victoria and NSW.

"I don't think there's any understanding whatsoever of the gravity of the situation," she says.

"The focus in NSW and Victoria has been on irrigator rights and a pipeline to Melbourne. Our concern here is that has completely detracted from the real issue that the river is dying. It's on death row and we are not addressing the issues fast enough to deal with it."

Peter Ker is water and environment reporter.