These 'Euro-Australian' attitudes have a long history in Australia and are so deeply ingrained in our culture that it will be a long process of re-education to change this situation. These attitudes began with the colonising settlers who first arrived in Australia. The feelings of the colonising settlers in Australia toward the landscape of their new home were predominantly those of unfamiliarity and displacement. The landscape from which they had come was very different from that of Australia, and there grew an urgency to recreate the European landscape. It was felt that the Australian landscape must be transformed to suit the purposes of a European culture based upon concentrated city living supplied by broad scale agriculture; the Australian bush is not conducive to this lifestyle.

To compound this inconvenience, feelings of unfamiliarity toward the Australian bush translated for the early settlers and still persist today into a sense of the bush being hostile, hiding dangerous native animals and people, and full of ugly, harsh trees only good for firewood and timber. The actions of the settlers, encouraged by government incentives, were to clear as much of this bush as possible to make way for rolling green pastures that would be fed by irrigation, 'making the deserts bloom'.

The Australian environment was little understood when these systems of environmental domination were put into place, and the environmental consequences of these actions are proving to be catastrophic. Our agricultural system and culture has been shaped out of this attitude, and the legacy with which we are left is one of our domination of the environment, rather than of cooperation with the environment. As a result we are left with a river system that has been abused rather than tamed by this process.

An engineering system based upon environmental domination has enabled us to have as much water on tap in our cities as we can use. By regulating the Murray River we have been able to irrigate the land making the countryside green with crops and grasses, and we have had a river that flows constantly all year round so that it can be navigated and diverted predictably and reliably. But we are now facing the consequences of 100 years of convenience and we are beginning to understand that we cannot continue to use the Murray as we have been doing for so long.

At present, after the United States, Australians are the heaviest water users on the planet (Hodson, 2002). This seems remarkable considering that Australia is the driest inhabited continent on the planet. We are going to have to change the way that we use the River, and this will involve improving water use efficiency but it will also involve a change in the attitudes of all River users. These new attitudes will need to accurately reflect the real constraints of living in a state where there is not an endless supply of water. Acknowledgment must also be made that every drop of water that we take from the Murray River is a drop that is no longer available to the river ecosystem for natural processes.

Land clearance

Since colonisation, it has been suggested that around 15 million tees have been cleared (Hodson, 2002). In the MDB, this vegetation clearance has resulted in loss of habitat for native plants and animals, deteriorating soil structure, acidification, and loss of topsoil through erosion. In the 1990's it was discovered that for every tonne of grain produced by farmers, approximately 13 tonnes of topsoil were lost, much of this being washed into the Rivers (Sinclair, 2002).

Widespread dryland salinity (see p. ) is a major consequence of this vegetation clearance, and as may be seen in the table below, is currently affecting over 2.5 million hectares Australia-wide (Beresford et al., 2001), with a further 15.5 million hectares at risk (Hodson, 2002). This salting of the landscape is killing vegetation and destroying the habitat of our native fauna. Large amounts of this salt wash into River systems such as the Murray, endangering the biodiversity of the River and threatening the viability of the River as a source of usable water to all who are dependent upon it.
Table of Land Clearance

River regulation

The health of the River and the ecosystems of which it is a part, were not given consideration in the systems of regulation and usage that have been devised and practiced by most of whom have lived within the basin. The costs of river use have generally been thought of as offset by the benefits to society of having access to reliable supplies of water (Sinclair, 2001).

Water use has increased to present levels where 80% of the natural river flow is diverted for irrigation and general use. Since 1940, water diversions from the River have increased from 3 000 Gigalitres (GL) to 10 000 GL per year (MDBC, 2002). Even in 1997 when the Murray-Darling Basin Ministerial Council introduced a moratorium commonly known as 'the Cap' to limit the amount of water that could be withdrawn from the River. An 80% withdrawal rate was decided upon, leaving only 20% of the original flow for natural processes. At the time, this level of withdrawal was considered by the Council to be appropriate.

Due to this level of water withdrawal, there is no longer the flushing of detritus and pollution during floods that, prior to regulation occurred three or four years out of five. As a result, there is a massive build up of salt occurring within the river basin, threatening all life within the basin.

There are over 70 000 wetlands covering over 222 000 Ha in the Murray-Darling Basin (Crabb, 1997). "Wetlands are the kidneys of the river systems - if they are healthy, the rivers will be healthy for all users" (South Australian River Murray Wetlands Management Committee, 1996, p. 1).

The wetlands of the MDB have been seriously degraded since regulation, with 50-80% severely damaged or completely destroyed (ACF, 2002). From the South Australian border and the Murray Mouth, 73% of the wetlands have become permanently inundated. "Along the Murray some 37 000 Ha of wetlands have been destroyed or greatly modified by permanent inundation following the construction of weirs and other structures" (Crabb, 1997, p. 62).

The pre-regulation flood and drought regime that governed the breeding processes of the native animals and plants of the basin is no longer occurring. Plants and animals of the river basin are not breeding and regenerating as regularly or successfully as they did before river regulation, threatening and endangering many species.

Similarly the carbon from the land necessary to sustain river life, which would normally have been absorbed into the Murray during flood, has now been greatly reduced. While some native species of flora and fauna are adapting to this change, the majority are not (Sinclair, 2001), thereby causing many native species within the Murray River to become endangered or extinct. This reduction in biodiversity will greatly reduce the health of the River, as biodiversity is a necessary condition for a healthy ecosystem.

Irrigation

The irrigation envisaged by the colonists and carried out by their descendants, is responsible for 95% of water usage from the Murray and has resulted in widespread irrigation induced salinity. Excess water from irrigation has seeped into the groundwater, either raising the watertable and bringing with it the salt, or taking the salt down through the soil into groundwater systems that eventually flow laterally into watercourses such as the Murray, resulting in the salting of the land and the River systems.

The amount of water diverted for irrigation has been largely responsible for only 20% of the natural river flow being left to flow down the River. As a result there is very little water available for the natural processes, which would normally ensure the health of the River, to occur. This level of water use is unsustainable and is fast depleting the health of the River.

Management of the River

The environmental consequences of a level of water use which allows only 20% of the river flow for natural processes, make clear the fact that this level is quite insufficient if we are to preserve what is left of the biodiversity and health of the River. This level is also insufficient if we are to ensure that the River and its basin are in a state that can be used by both current and future generations of people, flora and fauna, as the River is currently on the brink of collapse as a sustainable ecosystem.

In August of 2000 in the 'Review of the Operation of the Cap', the Murray-Darling Basin Commission (MDBC) declared that the current levels of water use set by the cap were not sustainable. However, reducing these levels of usage is happening very slowly and some would argue that this is in part due to the nature of the management structure.

The MDBC was designed as an advisory body of senior bureaucrats from the Commonwealth and State Governments of Queensland, NSW, Victoria and SA to advise the Commonwealth on issues concerning the River. The MDBC replaced the River Murray Commission in 1987 and has since, managed all of the structures associated with river regulation. In SA, the Murray is managed by the River Murray Catchment Water Management Board (RMCWMB).

A significant impediment to resolving the problems of the River is that the decisions of the ministerial council on this commission are required to be a consensus, and given the very different interests in the different states the probability of agreement is limited.

The big picture issues

Salinity

Increasing salinity

"Of the elements sustaining human life on earth, the quality of water and soil are two of the most crucial. Poor management of the soil-water system can threaten the survival of human populations by making it much harder to produce food" (Beresford et al., 2001, p. 2). The International Food Policy Research Unit is already concerned that soil productivity in the developing world is 'seriously limiting food production', as they have found nearly 4 million acres of farmland to be lost to salinity every year (Beresford et al., 2001).

Our activities within 40 kilometres of the River are believed to have a significant impact on the control of salt into the River, so how we manage activities within this distance is likely to be highly important to the control of salinity within the River and its basin (Hodson, 2002).

How much land is affected or at risk?

Recent estimates by the Australian Academy of Science suggest that 2.5 million hectares of Australian land are already salt-affected, with another 15.5 million at risk (Beresford et al., 2001). In South Australia, this figure is 600 000 hectares including already affected areas, and in the MDB 1996 figures indicate that 652 000 Ha of land are salt affected, with 9 374 000 Ha at risk (Hodson, 2002). Salinity is the greatest threat to the soil-water system.

Where does the salt come from?

There are huge quantities of naturally occurring salt in the earth. Over the millennia, salt has accumulated in large concentrations as a result of rainfall, the weathering of rocks, and the deposit of windborne ocean salt. Natural systems have prevented this salt from leaching out of the earth at great rates principally with deep-rooted vegetation systems (Beresford 2001). All over the world we have replaced much of this native vegetation with shallow rooted crops and we have irrigated many of these crops from nearby rivers, causing underground water tables to rise.

In the River Murray most of the salt comes from shallow soil salts which have been brought over millennia from the Eastern and Southern Coasts by the wind. Since the native vegetation has been removed, these salts are being released from these underlying strata and eventually they enter the River. This movement of salt is referred to as mobilisation (Hodson, 2002).

Salt mobilisation

At present 5.1 million tonnes of salt are mobilised every year. Around 2 million tonnes of this salt is exported through the river system to the sea. The remaining salt stays in the River and landscape or gets diverted into irrigation and floodplain wetlands. This figure is forecast to reach 6.8 million tonnes per year by 2020. If this forecasted figure were to be shifted by 20-tonne trucks, it would take 340 000 loads. To move this amount in one year, a truck would have to leave every 92 seconds! (Hodson, 2002, p. 12).

Murray-Darling Basin Salting. Tonnes of salt mobilised to surface in each State for selected years. State 1998 2020 2050 2100 SA 434,000 640,000 870,000 1,020,000 VIC 740,000 825,000 1,150,000 1,370,000 NSW 3,707,000 5,000,000 6,140,000 7,690,000 QLD 186,000 255,000 256,000 256,000 Murray-Darling Basin Salting. Annual total salt mobilisation in tonnes for selected years.   1998 2020 2050 2100 TOTALS 5,100,000 6,800,000 8,500,000 10,400,000

By 2050 it is forecast that 8.4 million tonnes will be mobilised, of which only 3.3 million will reach the sea. By 2100, of the total 10.3 million tonnes expected to be mobilised, it is forecast that only 3.8 million will reach the sea. These figures suggest that there will be an overall build-up of salt in the landscape of approximately 5 million tonnes per year (Hodson, 2002).

The two main causes of salt mobilisation are dryland and irrigation induced salinity.

Dryland salinity

Dryland salinity occurs due to the natural existence of salt in the Australian landscape. This salt exists as a relic of the ancient seas that once covered various parts of the continent. Before the colonisation of Australia, much of this salt lay dormant deep in the soil layers. Native, deep rooted vegetation used up the natural rainfall before it reached these layers and the surface soil remained relatively salt free. However, with land clearing making way for agriculture, this vegetation has been replaced with shallow rooted crops and grasses. Water used to irrigate these plants is now able to leach down into the ground. As it passes through the soil layers, the salt becomes mobilised and moves into groundwater systems. This saline water then slowly moves around the landscape, often discharging into rivers and affecting water quality. If this water gets close to the surface (usually less than two metres), the capillary action of the soil brings that water and salt to the surface. The water then evaporates and the salt is deposited on the surface. As this process continues, the salt is concentrated and areas of dryland salinity begin to form. Native vegetation and crops begin to die and the structure of the soil begins to change, leaving it powdery and more susceptible to erosion (Hodson, 2002).

Irrigation induced salinity

Irrigation is the process of placing water on the land to grow crops. Differing types of watering systems producing different problems regarding the degree to which salts become concentrated in the water and/or groundwater levels are caused to rise.

A rather disturbing notion centres in the fact that, with the single exception of the irrigated floodplains of the Nile in Egypt, all irrigation-based societies have destroyed themselves through desertification and salinisation of the land that supports them. This is true of societies from the Babylonian and Persian Empires through those of the New World (Hodson, 2002, p. 16).

The earliest form of irrigation was flood irrigation, the water travelling from the source along supply ditches or pipelines. Under current agricultural practices in Australia cotton crops are flood irrigated but the most extreme flood irrigation occurs in rice farming where large amounts of water continuously sit on the soil surface. Water is very likely to leak down through the subsoil to the water table. In a number of areas of rice cultivation the water table has risen dramatically (Hodson, 2002). Even where this leakage does not occur, evaporation will cause salt concentrations to increase in the surface water. This salt must eventually go somewhere.

Spray irrigation systems can be a problem as the water sprayed from these systems is in fine droplets and on hot days much water is lost to evaporation as these droplets pass through the air. As much of this water coming from the Murray contains salt, the concentration of this salt will increase before the droplet has hit the ground, sometimes to the extent that the salt will burn plants. Over-watering can still occur with these systems, again causing a rising of underground water tables or run-off containing salt particles from the land into nearby watercourses (Hodson, 2002).

Salinity in the Murray-Darling Basin in South Australia

Generally throughout the MDB, the water used from the River is for irrigation, rather than drinking. For this reason urban residents in these states are not aware of the water quality issues facing the Murray-Darling River. Residents are largely unaware that huge amounts of water from the River are supporting agriculture within their state. In NSW irrigation consumes 55% of the water from the MDB's rivers, and one irrigation company uses as much as the entire SA cap (Hodson, 2002).

Due to the extensive reliance of South Australians upon the River Murray for urban water use, there is a growing awareness in SA, of the dependence of all upon the health of the River. The current state of decline of the River has been a great impetus in this increasing level of education about the River.

At present, approximately 1.5 million tonnes of salt flow past Morgan annually, with 60% of this salt estimated to originate from interstate. These large quantities of salt are the result of both irrigation and the nature of the sediments below the Basin. As mentioned above, huge amounts of salt are naturally occurring in these sediment beds, and the shape of the basin is such that these salts, once released from their source must rise to the surface and enter the river channel before they can be flushed to the sea. The Basin is shaped like a shallow saucer, its rim formed by hills and a limestone barrier. This barrier prevents underground flows from reaching the sea (Hodson, 2002).

As a result of the salt discharge from these saline aquifers, the percentage of salt entering the River from within SA may well increase in coming years, particularly as a result of the recharge areas resulting from the clearance of the Mallee where water has entered groundwater streams through these recharge zones, raising them and generating flows. This water is now on the move but it will be some years before it all reaches the River (Hodson, 2002).


The effects of salinity

All living things require small amounts of salt in their cells and tissue fluids. Some plants and animals are particularly salt tolerant and have special cells and organs to excrete excess salt which would otherwise kill them, e.g. mangrove plants which excrete salt through their leaves, and crocodiles which excrete salt through their tear ducts. However most plants and animals do not have such mechanisms and will die if exposed to even small increases in salt loads. Those animals that do not die quickly may have their lives substantially shortened through kidney damage (Hodson, 2002).

As the land and waters become increasingly saline, species will be lost to these areas. Salt is toxic to grasses, stopping them from drawing water from the soil and killing them. Shrubs and trees may have differing salt tolerances but all have their limits and as salinity spreads throughout the basin it is killing the vegetation, including many salt-tolerant species. As a consequence, the soil erodes, and habitat for birds and animals are destroyed. Wetlands and floodplains are being affected in a very similar way with high salt levels killing vegetation and degrading wetland habitat. Saline groundwater is highly stressful for even salt-tolerant trees, which are only remaining healthy where saline groundwater is deep in the ground rather than shallow.

In the rivers themselves salinity is increasing as the salt remains in the channels rather than being flushed out to sea. These salt levels are expected to rise above World Health Organisation standards of 800 EC units (Electroconductivity Units or micro-siemens per centimetre) within the next 50 to 100 years. The costs of treating saline water for use by humans and in agriculture are currently approximately $46 million per year and rising. Costs are estimated to increase by $95 000 to $142 000 per each ECU rise (Hodson, 2002).

Other damage caused by salt includes damage to infrastructure such as buildings and roads in regional communities, and loss of productive farmland as previously described.

Salinity and floodplains

In addition to issues of inundation, salinity as previously described is affecting large areas of the floodplains. One quarter of the floodplains in SA has been affected in this way. Prior to regulation the naturally occurring salt mobilisation within the basin was flushed out of the system during floods, which covered the floodplains, washing the salt into the River, and eventually out to sea. At present, this flooding process is not happening more than once in every 10 or 12 years, and this salt is accumulating in the basin. In addition river regulation now maintains unnaturally high river levels, holding back groundwater from entering the system and resulting in groundwater rising to the floodplain surface and bringing the salt with it.