Once perceived as a serious environmental threat in Australia, dryland salinity has since dropped out of media and public view. However, as Jeanavive McGregor reports, it’s only a matter of time before the problem returns.

Dryland salinity can render farmland barren.

In 1999 headlines declared that dryland salinity was the greatest environmental threat that Australia faced in the 21st century.

Predictions were that half the farm and grazing land in NSW by 2050 could be lost, and that many rivers and creeks in the Murray-Darling Basin would be too salty to drink by 2020.

But 10 years on, it seems that estimates of the salinity threat, at least in NSW, were exaggerated.

A new groundwater study has revised the scientific methods that first predicted the crisis. It has found what farmers have been witnessing for years – that in NSW, the drought has salinity in retreat.

Still, the threat remains, with natural resources experts warning that salinity will return when the rain does, this time on a much larger scale and without the lag time of 10 to 15 years.

“It’s a time bomb and when it does rain again and the catchment gets wet we will have increased problems,” said Greg Bugden, Acting General Manager of the Murrumbidgee Catchment Management Authority (CMA).

For all the earlier clamour, the issue faded almost into invisibility, with funding and political interest dwindling. It is feared NSW could go the way of WA, where rising salt levels continues to ruin farmland and rivers forever.

But for now, farmers across Australia are more concerned with surviving the drought than planning for the inevitable return of the problem.

David Strong is one of them. In 2002 he returned to the Kyeamba Valley in southern New South Wales, where he grew up, buying a property on the Coreinbob Creek. He called it Coolbaroo.

The Coreinbob catchment has been classified as one of the most saline sub-catchments in the Murrumbidgee. Gums were dying; salt scalds stretched for hectares; creeks became increasingly saline.

Years of working in agricultural research in West Australia and Victoria had prepared him well. He planted hundreds of gums and native shrubs along ridges and large areas of lucerne along the creek flats to lower the water table.

Strong has seen for himself decrease in salt scalds. But he is unsure whether this is due to his farming methods or because of the historically low levels of rainfall in the area in the past seven to 10 years.

Another local farmer, Peter Lawson, who chairs the Kyeamba Valley Landcare Group, said: “To be honest, I think most people would be cheering if salt became an issue again, because it would mean that we had had a wet year.

“I certainly would be anyway. Someone asked me the other day whether salinity is a problem and I told them I couldn’t wait for it to be a problem again.”

What Lawson is seeing in the valley reflects the findings of the 2009 NSW Salinity Audit, which reviewed the way groundwater levels were measured in previous studies and how these levels contributed to salinity.

Salinity research and funding timeline

2009 to 2010 – Currently according to the Caring for our Country Business Plan there is no direct targeting or funding of salinity management.

The Australian Dryland Salinity Audit found that while NSW had only five per cent of land affected by salinity in 1999, there was a potential for 50 per cent of the land to develop salinity by 2050.

In other words, the 2009 audit has shown that the previous methodology had miscalculated the amount of land potentially affected by salinity.

Prepared in conjunction with the Connected Waters Program at the University of NSW, the report, Climatic influence on shallow fractured-rock groundwater systems in the Murray-Darling Basin, NSW concluded that variations in rainfall over the past century were the main trigger of soil salinity problems in NSW.

These findings contradict the popular wisdom that land clearing was largely to blame for the major salinity outbreaks in the 1970s and 80s.

One of the report’s authors, Professor Ian Acworth, head of the Connected Waters Program, said: “We distorted the concept of dryland salinity because we did not take account of variations in rainfall.”

“It turns out that after an extended dry period until about 1946, there was a significant shift to wetter conditions and the alarming increase in farmland that was affected by dryland salinity in the 1970s and 80s was a result of that shift.”

Acworth said the previous methodology made the mistake of assuming this rain pattern would continue. As it turned out, the last year with an above average rainfall was 2000 and the nine years since have been a historically long drought.

But Acworth warns against being complacent. “The good news for the salinity issue at least is that the balance has shifted back again to dryer conditions. It could give us 30 to 40 years of time to catch up and prepare our land for when it gets wetter again,” he said.

Bugden says that rather than waiting for the problem to reappear, this an ideal time to set preventive strategies in place.

He has been working in salinity management since the early 1990s and has seen what can go wrong – roads breaking up after three years; bridges corroding; farms suffering from large saline scalds and waterlogged areas. In Kyeamba Creek, salt took a huge toll, killing crops, river red gums and other native vegetation.

Against this background, Budgen worries that salinity is no longer a major concern for the NSW and federal governments.

He said: “The Murray-Darling Basin salinity strategy is still there, the NSW salinity strategy is still there but the NSW and Australian governments are no longer funding it.”

Time is ticking away, Bugden says. The possibility of salinity returning was evident early last year when the area had a small period of heavy rain. Within three months of the bores being turned off they had to be turned on again to protect infrastructure in the region. In just two or three months, the water table went from five metres below the surface to within two.

“The problem is still there and the lag time is not something that is going to take another 10 to 15 years to show and tell. If we get back to wetter situations in the Kyeamba Valley we could have saline scalds and the same problems reappearing again fast.”

To continue managing salinity, Bugden’s organisation finds itself forced to fund remediation projects by other means. For example, a scheme to plant trees in areas where salt has entered the groundwater falls under biodiversity funding.

He says he and his colleagues were making solid progress, with scientists telling them they were on the right track, when funding became harder to come by. He said “we now have to look at new endeavours to carry on”.

“It’s the political process, it’s a drought, it’s dry. So we can buy some time. But there is no doubt that it is going to come back and when it does come back funding will have to be applied to it.”