Salt Of The Earth Turns Australia's Rivers To Poison
Sydney Morning Herald
Saturday October 23, 1999
Much of Australia's breadbasket river system will be poisonous to humans and crops within 50 years - devastating agriculture, imperilling country towns, and creating massive regional unemployment across NSW.
In what is shaping as the biggest man-made disaster in Australian history, the salinity overload of the Murray-Darling river system cannot be fixed without a revolution in agriculture, involving the conversion dryland and irrigated farms to massive tree plantation.
The Murray-Darling Basin Ministerial Council's salinity audit, released yesterday, predicted that water in NSW and Queensland feeder rivers, including the Macquarie, Bogan and Namoi, would be undrinkable by 2020. The Lachlan, Castlereagh, Gwydir and Macintyre rivers were also in deep trouble.
The booming cotton industry faces ruin, as the crop cannot cope with the salinity levels predicted.
The Federal Environment Minister, Senator Hill, said the audit was an "alarm bell" ringing after 100 years of agricultural practices, including land clearing - which still occurs on a large scale in central north-west NSW and southern Queensland.
The Agriculture Minister and chairman of the Murray-Darling Basin Ministerial Council, Mr Truss, said the audit revealed a "disaster area" and illustrated the need for Australia to become the "clever farming nation". The basin was a "very, very important part" of Australia, worth $20 billion a year in gross production. It produced 40 per cent of the nation's agricultural wealth.
"Its quite clear from the audit that there are many warning signals," Mr Truss said. "If nothing is done within a few decades large areas which are currently highly productive will cease to be able to contribute to the communities that are so dependent upon them.
"So business as usual is simply not a viable option. There will need to be changes in land use on a regional, catchment and farm scale."
The commission is using the audit to prepare a draft basin salinity management strategy for the Ministerial Council's consideration by June next year.
Rising salinity levels result from the landscape's inability to cope with increased water loads in groundwater. The native landscape could absorb about five millimetres a year but farming has poured 100 millimetres of water and nutrients annually into the earth over the last century and the resultant rising water table has leached salt stored for aeons into rivers, billabongs and swamps.
The salinity audit established a trend - river valley by river valley - for salt mobilisation and predicted increases in salinity if Federal and State governments, towns and farming communities did not implement new management techniques. Work by the Murray-Darling Basin Commission had concentrated on the impact of irrigation on the system but the salt audit is the first research into the impact of dryland farming.
Since the Hawke government declared salinity a major problem in 1989, work on the lower Murray had reduced salinity to below the World Health Organisation 800 EC (E. coli) threshold for desirable drinking water.
But upstream poisoning of the system from irrigation and catchments in NSW and Queensland is jeopardising Adelaide's water supply. The audit predicts lower Murray salinity rising from an average 570 EC currently to 790 EC in 50 years and 900 EC in 100 years.
The Macquarie, Namoi and Bogan rivers would exceed 800 EC within 20 years and the 1,500 threshold for irrigation crop and environmental damage - with the killing of fauna - within 100 years. The Lachlan and Castlereagh rivers would exceed safe drinking limits within 50 years.
The principal research scientist at the NSW National Parks and Wildlife Service, Dr Richard Kingsford, said rivers such as the Macquarie, with internationally significant ecosystems, were being degraded.
"River flows are considerably less than they used to be, which means we are not getting as much dilution as we used to," Dr Kingsford said.
"Unless we halt the salt degradation, it means that a lot of the complexity of that ecosystem will be lost."
RIVERS OF SHAME Average river sainity (EC) Thereshold for desirable drinking water is 800 EC. RIVER Gwydir 1 1998 560 2020 600 2050 700 2100 740 Castlereagh 2 1998 640 2020 760 2050 1,100 2100 1,230 Murrumbidgee 3 1998 250 2020 320 2050 350 2100 400 Lachlan 4 1998 530 2020 780 2050 1,150 2100 1,460 Bogan 5 1998 730 2020 1,500 2050 1,950 2100 2,320 Macintyre 6 1998 450 2020 450 2050 450 2100 450 Namoi 7 1998 680 2020 1,050 2050 1,280 2100 1,550 Macquarie 8 1998 620 2020 1,290 2050 1,730 2100 2,110
© 1999 Sydney Morning Herald
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