The Murray: A River Worth Saving: The Murray Darling Basin

Source: The Murray; Murray Darling Basin Authority

The Murray River affects the livelihood and well-being of millions of Australians, both urban and rural dwellers. Products of the Murray irrigations are consumed by Australians every day. As well as its economic importance to agriculture and industry, the Murray is a resource of immense environmental and social value. Its waters maintain over 2,520 kilometres of unique aquatic and riparian environment which has evolved over millions of years. It is a major source of domestic water for around 1.25 million people. Hydro-electricity generated from the River and its tributaries makes a small but important contribution to supplies in the ACT, Victoria and New South Wales; meanwhile, each year the Murray Valley becomes increasingly popular for recreation and tourism.

The Murray River – multi-use Resource

• Hydro-electric Power Generation
• Irrigation
• Domestic, Industrial and Stock Water Supply
• Recreation and Leisure
• Habitat

The Murray is now a regulated river

In less than 200 years it has been transformed by the hand of man. Its water resources have been harnessed to support productive agricultural areas in Australia. The Murray and its tributaries are controlled by dams and weirs, and water from the Snowy Mountains has been diverted westward across the Great Dividing Range to augment the Murray’s flow.

Achieving this control over the river system has involved a massive effort and a huge investment of money and human skills. The benefits of the assured water supply to the dry inland and the people of South Australia have been of paramount importance in the Nation’s development. But this control and use of the Murray’s waters has had a cost; the full extent of which is only now becoming apparent.

Clearing of native vegetation on the slopes of the Great Divide and across the vast dry plains of the river valley has transformed the land and enabled the production of crops and livestock, which provide a vital contribution to the Nation’s wealth. But this clearing has allowed more rainfall to move down through the soil, filling the underground gravel and sand beds until they are now overflowing, forcing salty groundwater to the surface and into the River.

Along the rivers of the Murray-Darling Basin, irrigation has enabled a massive increase in agricultural production; but this production cannot be sustained unless the waterlogging and salinization resulting from irrigation and clearing can be controlled. Redgum forests along the rivers have been felled for timber, burnt for firewood and cleared for farms and towns. The floodwaters needed to sustain these forests have been reduced by river regulation. Grazing by livestock along the river banks prevents regeneration.

Aboriginal burial sites and midden areas have been flooded by dams. Levees have been built to keep the River in its channel and protect adjacent farms and towns. The wetlands and floodplain beyond the levees are now alienated from the River, reducing habitat for fish and waterfowl. Towns along the River have grown into cities with little concern for effects on river water quality. Together with the pollution from stormwater and sewage from these cities, some of the chemicals used, such as pesticides and herbicides on agricultural land inevitably wash into the streams. Nutrients in treated sewage and irrigation drainage water increase the frequency and intensity of algal blooms which contaminate drinking water supplies and increase the cost of water treatment. Mercury from old goldmines on the tributaries has contaminated river sediment and is now found in the tissue of the fish which eat the small animals living in the sediment. Pesticide residues also accumulate in the fatty tissue of these fish.

Over recent years the Murray has become increasingly important for recreation and tourism; some predict that the revenue from visitors will come to rival that from agricultural production. But if allowed to grow, uncontrolled tourism will itself accelerate the rate of decline of the river system until there may be little worth coming to see.

The Tyranny of Small Decisions

The salinity problem serves as a parable for the other problems now emerging for the River. The destruction of a river does not happen overnight. It comes as the result of years of unplanned and uncontrolled development, from the gradual accumulation of the effects of an increasing number of minor incidents.

It is the “tyranny of small decisions” which has led to the destruction of many of the world’s greatest rivers. Rivers such as the Elbe, Danube, Delaware, Humber, Illinois, Mersey, Mississippi, Ohio, Rhine, Rhone, Trent and Vistula (to name but a few) are now little more than sewers conveying untreated human and industrial wastes to the sea.

“Health” is a relative term. While there is no doubt that the Murray-Darling River system is subject to the same ongoing processes of degradation which have lead to the destruction of rivers overseas, it is still a relatively healthy river system. Unlike most developed rivers in Europe and North America, along the Murray there are:

• no discharges of raw sewage
• virtually no industrial waste discharges
• still many productive wetlands
• still healthy tracts of floodplain vegetation and native forests
• still the full complement of native fish species, albeit in greatly reduced numbers.

Our inland rivers unique advantages, which if effectively utilised will enable us to make sustainable development a reality. These advantages include:

• our low population density
• a climate which favours off-river waste disposal by irrigation or evaporation
• ample land for off-river waste disposal
• a low level of industrial development
• a high current level of sewage treatment
• the potential to use this effluent profitably in irrigation

The Murray’s characteristic features – low gradient and highly variable flow – impose constraints and present opportunities for improved management. Dams must be large to capture the occasional high flows and preserve large volumes of water for use over long droughts. But the flat terrain limits sites available for dam construction and limits the extent to which river flow can be captured and harnessed. Despite all the dams built on the Murray and its tributaries, flow in the Murray is under “regulated” conditions (that is, carrying the water deliberately released from storages) for less than 60% of the time. When there is more water in the River than is needed for irrigation, it can be used to meet the needs of the forests and wetlands of the River floodplain. This is an opportunity which can be exploited to maintain and improve the river environment.

Towards Effective Management

The choice is still before us. We still have time to rehabilitate and maintain the water quality and environment of our inland rivers, provided we can muster the resources and political will to implement effective river management policies. In particular, we need to establish precedents and standards for waste disposal and environmental protection which will avoid the obvious mistakes made elsewhere. For the professionals involved, this will require looking critically at the improvements to river management developed in other countries in terms of how effective they have been. Economists and planners will need to question and extend the tools available to them, such as cost-benefit analysis, so that adequate value can be given to the maintenance and improvement of water quality and river environments for future generations.

As pong as our rivers are assumed to have some excess capacity to accommodate human and industrial waste, we can be sure that the process of slow, creeping degradation will continue. If “sustainable development” is to have any real meaning for the rivers of the Murray-Darling system we need to establish a commitment to maintaining, and where necessary improving existing water quality. We must implement policies which aim at minimising the pollution of rivers and not impose upon them a self-purification capacity which they never had as clean streams.

Over the past decade, much as been achieved. State Governments have moved to improve water quality legislation so that there is now a general commitment to maintaining existing river quality by requiring the best practical methods of waste treatment and disposal. A Salinity and Drainage Agreement has been developed, committing the four governments involved to joint action to reduced river salinity.

Many towns and industries along the 2,520 km of the Murray River have demonstrated a practical commitment to the preservation of the river by implementing improved waste disposal schemes. There are now only a few towns which still rely on river discharge for the disposal of treated sewage effluent. Along the whole length of the Murray River there is only one large industrial discharge to the river; that from the newsprint mill at Albury.

There is no grounds for complacency. The towns still discharging will soon become cities and with much larger populations; and there will soon be other industries wishing to use the advantages of the cheap clean water available from the Murray River.

As population continues to grow and tourism increases there will be new pressures on the river system. Houseboats are already widely used and the waste disposal facilities available to them are inadequate. Caravan parks and marina developments are springing up along the River and intensive agricultural developments such as piggeries and cattle feedlots threaten the water quality of tributary streams. Redgums continue to be felled with little control or thought to the future. Wetlands are alienated and reclaimed for farm land. Fish populations continue to decline. It is by good luck rather than good management that we still have resources worth saving and only good management will save them now.