By Lisa Macdonald
Before the last federal election, the Labor Party and Coalition placed restoration of the Murray Darling river system at the centre of their environment policy packages.
While environmentalists agree that their responses were far too little too late, they did reflect a growing awareness of and sense of urgency about the severity of the crisis in this largest and most important of Australia's river systems.
The Murray Darling system drains a vast, predominantly arid or semi-arid catchment and is the critical factor in the settlement and agricultural development of large areas of NSW, Queensland, Victoria and SA.
Under natural conditions, water flow in the Murray Darling catchment is both limited and highly variable. Governments and irrigators have therefore invested huge sums in dams, weirs, private diversions, on-farm storage and pumps to achieve reliable supplies. In the process, water has been seriously over-extracted, with disastrous ecological consequences.
In an article in the February 1995 issue of Habitat Australia, the Australian Conservation Foundation's Jason Alexandra and Tim Fisher point out that the provision of irrigation water is heavily subsidised by the taxpayer. They argue that the resulting low price of Murray Darling water has contributed to its overuse.
Today, most of the water flowing through the Murray Darling system is extracted for off-stream use. Ninety-five per cent of it is used for irrigated agriculture, the remaining 5% being used by major cities such as Adelaide and Canberra and smaller centres located along the rivers.
According to the ACF, average flows at the Murray mouth have been reduced to 20% of flows under a natural regime. While the Murray mouth once experienced drought-like flows only five years in every 100, these conditions are now apparent 62% of the time.
Many wetlands, flood plains and billabongs are drying out, causing a drastic decline in the abundance and diversity of native fish, waterbirds, frogs, invertebrates and plant species. Native fish populations have been declining for many years, and some species have disappeared altogether from the system. According to Ocean Watch, over the last 50 years the reduced volume and changed water flow patterns in the Murray Darling system, combined with vegetation loss and the building of barriers to fish migration (dams and weirs), have resulted in declines in the number of golden and silver perch, for example, by 75% and 95% respectively.
Simultaneously, European carp and other introduced species have been able to out-compete native species and have proliferated. The May 1 Sydney Morning Herald reported on the first attempt to count the numbers of carp which now infest some inland rivers. While the final results of the study are not yet available, scientists involved were shocked to find an average of one carp per square metre in the stretch of the Bogan River (a tributary of the Darling) which was studied.
This concentration is three times greater than threshold above which scientists have said carp would cause damage to the environment: carp disturb river bottom and bank sediments, destroying aquatic plants and releasing nutrients which promote outbreaks of blue-green algae.
The low-flow conditions created by water overuse have also resulted in steadily increasing salinity levels within the river system, in some areas to a level which renders the water unusable by humans and native flora and fauna alike. Further, when saline ground water enters the rivers in low-flow conditions, this leads to a massing together of the suspended material in the rivers, stimulating algal growth.
The Murray Darling flow problems are compounded by pollution of the water. The sources of pollution include agricultural chemicals, sewage effluent (which is still largely untreated), urban run-off, nutrients and sediments.
A group of users which is contributing disproportionately to the mess is the rapidly expanding cotton industry of southern Queensland and northern NSW. This agribusiness not only consumes massive quantities of water for irrigation, but also feeds large amounts of run-off into the Darling which contains concentrated nutrients picked up from nitrogen- and phosphorous-rich fertilisers.
The effects of river pollution are compounded by changing flow regimes. They are also exacerbated by the erosion of riverbanks, which is caused largely by the clearing and over-grazing of land alongside the rivers. Riverbank erosion increases sediment loads, which release even more nutrients into the water.
Periodically, the depth and extent of the multifaceted crisis in the Murray Darling system is revealed in a major event such as the blue-green algae bloom of 1991, which poisoned more than 2000 kilometres of the Darling River.
The latest indication has occurred in NSW, where, for the last three months, extensive bank collapses have occurred along both sides of 1500-2000 kilometres of the waterway. On some sections of the Darling, 150-metre long sections of the riverbank have collapsed into the main channel, dumping tens of thousands of tonnes of soil into the water, sweeping thousands of ancient river red gums along with it.
The slumps are so severe that the NSW Department of Land and Water Conservation has said that any attempt at remediation is impossible, while the state government has commissioned an inquiry into the effects and causes of the erosion.
Despite all of these indications and more than a decade of warnings by scientists and environmentalists that the Murray Darling river system is slowly dying, the seriousness of the situation is still not acknowledged by many of the power brokers in Australia.
Last month, for example, the establishment media chose not to report on the results of a new study conducted by the ACF which underlines the seriousness of this problem. The ACF's "Survey of Freshwater Ecologists' Views on Ecological, Conservation and Management Issues in the Murray Darling River System", the first of its kind, was conducted in late 1996/early 1996. It found that the degradation of the river system is more or less all-pervasive, covering in-stream environments, flood plains, wetlands and riparian environments.
Commenting on the apparent lack of interest in the survey results, Fisher, who coordinated the survey, told Green Left Weekly that it was a constant battle for environmentalists to convince governments and the Murray Darling Basin Commission to give as serious consideration to the ecological costs of the Murray Darling crisis as they do to the strategic and economic aspects. This is despite the Council of Australian Governments' 1994 Water Resources Policy commitment to restore and maintain environmental flows in Australian rivers.
While various agreements between different levels of government have been put in place in recent years to examine options for reducing water use, constant debate and powerful opposing interests have stalled any major action. On the contrary, the Queensland state government is actually increasing the water allocation from the rivers in this system, and is also planning more dams.
The problem is compounded, says Fisher, by extensive fraud in water extraction.
Another major concern for environmentalists is the possibility of the privatisation of Murray Darling water resources. At present irrigators in the Murray Darling Basin are allocated water rights through licences which have to be renewed every few years. According to Fisher, some state governments, led by Victoria, are aiming to convert water entitlements into permanent rights so as to "protect investments in irrigated agriculture".
The ACF has been advised that a reduction of approximately 20% in the amount of water extracted from the system is required to prevent its further decline. If privatisation goes ahead, returning enough water to the system to save it would require governments to buy it back at a cost of hundreds of millions of dollars — an expenditure that no government is likely to agree to.
Whatever the outcome of the states' water "resource security" plans, however, Fisher argues that the cost of reclaiming water for the rivers should be borne in part or wholly by the irrigators themselves since they are the primary and immediate beneficiaries of the water extraction.
Together with programs to re-establish natural flows, stop and repair riverbank erosion, protect native flora and fauna and stop the pollution of the waters that remain, the task of saving the Murray Darling system is a huge one. As one respondent to the ACF survey said, the situation has been allowed to deteriorate so far that "a return to the original conditions is impossible. However, closer mimicking of natural conditions would be beneficial, and is possible."
For this possibility to become a reality, however, the unwillingness of governments to legislate in the interests of environmental survival and sustainability before the profits of agribusiness will have to be turned around. The Howard government's unwillingness to devote resources to the problem unless Telstra privatisation is approved is so irresponsible as to defy belief.
And the environmental vandalism is not confined to the eastern states: in Western Australia, despite the lessons and costs of devastation of the Murray Darling, the state government is about to approve a massive new cotton development which will involve damming, extracting large quantities of water from and polluting the crucial Fitzroy River. The battle to save Australia's rivers is now more urgent and important than ever.