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9. Salinity

by John Schooneveldt

December 2005

Contents

1. Introduction

2. Understanding salinity

3. The role of salt

4. The role of water

5. The waterbalance

6. The role of soil

7. So, what are we doing wrong?

8. Managing salinity

9. Deep-rooted plants

10. Reduced irrigation

11. Engineered approaches

12. The water balance approach

13. Free water

14. Run-off waters

15. Impounded waters

16. Water-pricing policy

 


SALINITY

A DISCUSSION PAPER


by John Schooneveldt

1. Introduction

The “experimental gentleman” on James Cook’s second voyage of discovery, Johan Forster, had a problem. That was how to measure the temperature of the ocean depths without the readings on his instruments being contaminated by the intervening temperatures. The anthropologist/historian Greg Dening, to who I am indebted for this story, observed that recalling past events is also like this. One can go back into the archives of the mind, but Dening wondered, how can one dredge up past memories without them being corrupted by the present.

This problem is much more widespread than Dening suggested. It applies to all scientific and much of human endeavour. How can one’s observations get past one’s pre-conceptions and pet theories and be taken at face value?

The problem is particularly difficult when dealing with salt. It is not salt that is the problem - it is a vey useful and essential chemical. The problem is the plethora of explanations, theories and vested interests of those who, in one way or another, deal in salt both as a good and as a bad.

In this paper I argue that salinity is a symptom of the way we mismanage water. It is not a “problem” but a simple management issue.

2. Understanding salinity

Three important and well established facts need to be taken into account to understand salinity: (1) the role of salt in living systems, (2) the role of water in moving salt through those systems, and (3) the role of soil in holding water and buffering salt.

3. The role of salt

Salt is essential for life and the healthy functioning of all living cells. Individual cells are equipped with ion channels that regulate their salt levels. Organisms have evolved a diversity of mechanisms to maintain an appropriate salt balance as determined by their biohistory or evolutionary development.

We do not know how life on earth started, whether deep within the earth’s crust, in its seas or even by coming in from outer space. But what is clear is that our ancestors and the ancestors of all living land-based plants and animals on earth today spent a substantial part of their existence in the sea. There they evolved a special relationship with salt. As a result, concentrations of chemicals in our blood and tissues match the concentrations that existed in the seas when our ancestors evolved. Since those times aquatic organisms have a capacity to maintain balanced salt levels − keeping out excessive salt in highly saline areas and retaining enough for optimizing their metabolism in fresh and brackish water environments. When some species moved to inhabit the land they evolved new mechanisms to retain the salt they needed, but lost their capacity to withstand excessive salt. As a result many land based plants and animals vary greatly in their sensitivity to salt.

4. The role of water

Water is a major constituent of all living organisms. The human body for example is about 70% water, chickens are 75%, shrimps and prawns 80% and tomatoes and lettuce a whopping 95% water. Salt, which is highly soluble, is moved in and out of cells, organisms and landscapes by water. Ion channels in cell membranes control salt movements in living organisms. When organisms die, their salts are released during decomposition processes and taken up again by new organisms. Excessive land clearing then results in this salt not being taken up.

In addition, organic matter in various stages of decomposition has the capacity to bond with the released salt thereby immobilising it. Through this mechanism organic matter plays a major role in inhibiting the movement of salt. However the loss of organic matter from soils, which is occurring at an alarming rate, results in a breakdown of this buffering and is thus a major factor in increasing salinity levels.

5. The water balance

It is a requirement for all healthy organisms that water in equals water out. If you drink more than you excrete through perspiration or in other ways, you build up fluid. If you drink less, you dehydrate. So it is for all living organisms and stable natural systems such as lakes, underground aquifers and surface rivers and streams. Importantly for salinity, the same rule applies to levels of soil moisture whether associated with soils supporting forests, grasslands or deserts. For an organism to survive or an ecosystem to be sustainable, water in must equal water out.

These in-out flows are not simultaneous of course. In healthy systems, the water is doing a lot of good things while moving through the system, for example, by delivering nutrients and removing undesirable wastes. All this activity results in time delays between input and output that can vary greatly from species to species and from system to system. For example some very sensitive plants will survive only minutes without water, camels can last days and desert communities may survive for years without rain.

The capacity of a system to handle delays is referred to as the resilience of the system. Organisms have evolved a wonderful array of mechanisms to bolster their resilience. For example plants such as eucalypts and casuarinas shut down operation during dry conditions, others such as cacti and succulents, store water during good times for use when water is scarce.

In addition to its resilience, the way water enters and leaves the system is also important. For example in hot weather we lose water through perspiration. This mechanism makes use of the natural drop in temperature that occurs when water changes from a liquid to a gaseous state (what scientists call the latent heat of evaporation). Many other animals and plants have evolved similar mechanisms. The cumulative effect of many plants transpiring water is what makes forests so much cooler than, say, an area shaded by a tin roof.

In summary, nature maintains a balance between inputs and outputs within the resilience of each system. This is a fundamental principle that we have forgotten in the way we manage land and water. By adding water in excess of what is required, say through leaky irrigation systems, the excess water, even if it is of good quality, is a pollutant in that system just as adding excess carbon dioxide to the atmosphere is a pollutant. Conversely, by regulating rivers and restricting flooding and natural flows, the loss of water from flood plains is killing natural forests and destroying good agricultural land.

The damage being done is not only the result of adding too much water in some areas and taking it away in others, it is also the result of the timing of minimal and peak flows. Australia’s naturally dry summers in the southern parts of the country have river flows at their lowest during the summer and at their peak at the end of winter (a pattern that is reversed in the monsoonal north). Through regulation of waterways those flows have been reversed at great detriment to the native species of birds, fish and other animals that depend on the natural summer/winter cycles but also to the ecosystem services delivered by these natural systems. For example, the regular flooding of rivers replenished soil moisture on vast areas of flood plain for the benefit of crops and other plants on which we depend. Importantly, it also cleans the water as it releases it slowly back into the river system.

6. The role of soil

The capacity of soil to hold water and buffer salt is the third vital factor for understanding the salinity issue.

It is impossible to overstate the importance of soil, for all life on land depends on it. Imagine it as a thin spongy layer covering the surface of the land. This sponge is made up of organic matter and particles of various sizes resulting from the breakdown of the parent rock material. Coarse particles form sandy soils and very fine particles form clay soils.

Soils vary in their water holding capacity, but can be thought of as a reservoir that holds fresh water for later use by plants. Water leaves this reservoir very slowly through deep drainage into rivers and streams and evapo-transpiration through plants. It enters soils naturally through rain and inundation or flood. Human activities have hugely affected the water balance in soils by adding excessive amounts of water in irrigation areas and withholding water from other areas by regulating streams and floods. In dryland (non-irrigated) areas excessive clearing has decreased soil organic levels thus mobilising salt.

Clearing has also exposed large areas of soil to hot desiccating conditions that greatly increase evapo-transpiration and inhibit plant growth. In some areas, when it does rain, the amount of water leaking into the sub-soil ground water increases, raising water tables and bringing up ancient salt.

The precise ways in which soil buffers salt is not well understood, but it is easily tested. Slowly pass some salty water through some organic matter such as garden compost. The water that comes out is less salty than what went in. Certain soils, such as sodic soils, lock up salt molecules so that they are effectively immobilised. The salt is still there, but it does no harm. Organic matter also prevents salt mobilisation. Somehow the salt is locked in so that it is no longer a danger for salt sensitive plants and does not salt up rivers. The implication of this is important for salinity because a reduction in the depth and structure of soil reduces its capacity to buffer salt.

Unfortunately, many farming practices have resulted in massive reductions in the depth of soil and loss of organic content and hence the capacity of soil to hold water and buffer salt. These practices also result in increasing leakage to ground water, raising water levels and bringing up ancient deposits of salt, compaction of soils, increased run off, erosion of waterways, loss of soil nutrients and so on.

As every gardener and farmer is well aware, soils vary greatly from place to place, not only in terms of their fertility, but also their structure and water holding capacity. Woody plants tend to occur on coarser soils, and grasslands tend to dominate on clays. Woodland (trees + grass) occur on heavier textured soils and forests (trees + shrubs) occur on coarse textured soils. Significantly, the water use in each of these areas, while dependent on climatic factors, follows the standard sustainable pattern of water in equals water out. Root systems and metabolic processes have evolved beautifully to match water availability and maintain the water balance.

In areas of rainforest, which typically grow on very nutrient poor soils, the water/nutrient cycle operates very rapidly. For example, Fraser Island, which is a sand island with very little water or nutrient holding capacity, supports substantial areas of rainforest. Nutrients from decomposing leaf litter take about 30 minutes to be detected in the crown of the taller trees. In desert areas, during dry times the same process takes weeks. Again, each system strives to maintain its water balance.

7. So what are we doing wrong?

First, let’s see what needs to happen if we are to farm sustainably. What we are doing wrong is the extent to which we have departed from ideal sustainable patterns.

To farm sustainably we need first to maintain water and nutrient balances.

From a water point of view we can grow any crop that soil types and climatic conditions allow. Growing water thirsty crops such as rice and cotton are not a problem if we can engineer water delivery systems that maintain the water balance. If an engineered delivery system cannot maintain the water balance in a particular area (for example if it leaks) that type of crop should not be permitted in that area. This is primarily a zoning issue. Just as regulators place restrictions on building on flood plains for obvious reasons, or have special engineering requirements in, say, earthquake prone regions, so there must be restrictions on leaky irrigation systems. Of course a prohibition on a particular leaky system is a great incentive for developing systems that do not leak and, as we will see, is a much more powerful incentive than pricing (with or without regulation). While paying more for water will no doubt reduce wastage (and hence leakages) the cost of mitigating the damage done by past leakages will continue to be borne by the public now and by future generations. Building the full externality cost into the price would make water so expensive that the cost of food production would become prohibitive.

Appropriate zoning, as we will see, is the most cost-effective way to reduce leakages while continuing and even increasing production in areas where leakages can be managed. It also provides a huge incentive for better engineering of delivery systems. Zoning that differentiates between rural, urban, industrial and residential, is well-established practice. Similar approaches could restrict activities that leak water and upset the water balance.

To farm sustainably, we also need to replace the nutrients and organic matter we remove when harvesting crops. At present much of that organic matter finds its way into landfill, the sewerage systems of our larger cities and those of our trading partners. The cost of managing this organic “waste” is huge. At the same time farmers are paying increasingly for synthetic fertilizers and other input costs. Returning the organic “waste” to the farm will be costly and require some innovative technologies and incentives, but the savings in urban waste management and artificial fertilisers will offset this. The improvement in soil structure will have many additional benefits: it will reduce the need for irrigation water, leakages into ground water, surface run-off and erosion. One simple systems change will address all these so called problem areas simultaneously, and do so at no net cost.

8. Managing salinity

The above two suggestions – zoning out technologies that leak surplus water into soils and and strategies for returning organics to the soil – involve whole system changes. They are hardly ever mentioned in the context of salinity where three other ameliorating strategies are typically suggested. All three are expensive, both in dollar and political terms, and only partly effective. Before considering a new way of thinking about the management of salinity, we will deal with the three widely proposed approaches first. They are to:

• plant deep-rooted perennials, especially trees

• reduce irrigation inputs and increase environmental flows and

• engineer the whole farm to make use of the salt.

I take each in turn.

9. Deep rooted plants

The planting of deep-rooted perennials and trees, especially in areas where tree clearing in the past was excessive, is an obvious and sound mitigating strategy to restore the natural water balance of an area. Beginning with salt tolerant species and progressively replacing these with more appropriate plantings as water levels drop seems logical and has been proven effective. The Dutch folowed the principle of successive plantings from salt-tolerant to deep rooted plants. They did it in a relatively short period and on a substantial scale when turning what was once the bottom of a sea into productive farming land.

First and foremost they controlled the water balance, bringing in enough fresh water to leach out the salt, This was accompanied by plantings thus keeping the water table low enough so as to not bring the leached salt back up. This is the same process that has been happening naturally in Australia over millions of years as our inland seas dried up and the wind blown salt slowly leached down into ground waters and into low-lying areas.

However, while we continue to disturb the water balance through adding excessive amounts of water in some areas (thus mobil-ising salt) and withholding water from others (thus halting the natural leaching processes), tree planting will not of itself do the job. We have to address the heart of the problem, which is our failure to maintain an appropriate water balance in the engineered systems put in place over the last century.

10. Reduced irrigation

Environmental flows that flush out the excessive salt in our river systems and restore some of the natural flood cycles also address symptoms but do nothing to address fundamental causes. Nor do salt drains. They are just a mechanism for shifting the problem from one area onto someone else’s patch.
There is already evidence that the cap on irrigation waters (imposed at great political cost) has resulted in more people sinking bores to make up the shortfall in their water allocation. The amount of water taken by irrigators from ground water is replaced by a reverse flow from the rivers that inevitably replenishes the depleted aquifers. There are two results of this. First, the bore water is typically more saline than the surface irrigation waters it replaces, thereby reversing the natural leaching of salt and adding even more salt to the surface. This will massively accelerate increases in salinity in an area. Second, part of the extra amount of water made available for environmental flows naturally replaces salty ground water now raised back up to the surface. As a consequence, limited water may be left for the environmental flows. The result is the exact opposite of what is intended.

Do not misunderstand. Environmental flows are good, but their effect is worse than doing nothing if increased irrigation from ground water continues to be allowed. This is not to say using bore water as an emergency backup is bad. Using the water balance principle, we can take out as much water as needed during dry times provided it is put back when there is plentiful water available. Again the Dutch do this. Most of that country’s potable water is abstracted from ground water, and is replaced from river sources (which have been through numerous human kidneys and industrial plants already) to replace it and maintain the water balance. Failure to maintain this balance (as in many other coastal areas) will see an incursion of seawater into aquifers.

11. Engineered approaches

The third approach to saninity is to do nothing to address the fundamental causes but engineer our agricultural systems to adapt and make use of the increasing salt levels. For example, it can be business as usual on higher slopes where natural leaching can control salinity levels aided, if need be, by on-property salt drains. Lower down, salt tolerant crops could be planted using salt drains to prevent excessive build-ups. The salt drains would feed into pond systems where salt tolerant species could be grown out such as brine shrimp and other crustaceans and fish. Finally as salt concentrations build up even more, the salt could be fed into solar ponds where the remaining water is evaporated and the salt harvested as a commercial product.

Engineered solutions like this might work on a small scale, but it is difficult to see how they would work on a vast scale for land areas as large as the Murray Darling Basin or the West Australian wheatbelt.

Now assuming the scale and cost problems could be overcome, the quantities of salt safely leached away below ground level would in time become mobilised and result in ever larger mountains of salt well beyond commercial requirements and creating yet another massive disposal problem.

In summary, while tree planting, environmental flows and engineered solutions are all useful to some extent, they do not address the fundamental issue. In the next section I suggest an approach that uses a mix of regulatory and commercial approaches that will be less painful and more effective than the three strategies developed so far.

12. The water balance approach

This is based on the idea that salinity can best be managed by working with, rather than against, the natural movement of salt through Australia’s diverse ecosystems. It involves maintaining the water balance in everything we do in this country in all sectors: urban, rural, industrial and agricultural, and at all scales: suburban block, factory, rural village, family farm and agribusinesses. Where current systems are out of balance, we need to redesign them to be in balance. This is a relatively simple engineering problem. Our infrastructure (dams, pipes, irrigation channels) is ageing and increasingly expensive to maintain. These are very large systems affecting many people. This makes them politically sensitive, attractive terrorist targets and catastrophic when they break down. Recall the Sydney water scare of a few years ago and the current water restrictions.

A new approach involving a move to smaller scale, decentralised autonomous water systems can be achieved progressively as the cost of maintenance of the existing infrastructure becomes prohibitive. This is also consistent with the first two recommendations of the 2003 Johannesburg World Summit on Sustainable Development: to devolve responsibility for water from central governments to regions and include stakeholder groups in decisions. For new developments this process can begin immediately. Smaller systems have the advantage of being locally managed, so that both inputs and outputs are the responsibilities of the local authority, reducing disputes about who owns the water and who cops the effluent. Autonomous systems, by definition, are designed to use only the water necessary for the development, no more and no less. They draw on natural flows and return them to those natural flows so that the water balance of the natural system in which the development is embedded is maintained. Ideally outputs of such systems should be upstream from inputs.

To facilitate the transition from our current ageing large scale and leaky systems and to create the commercial opportunities that will transform our current system we need to put in place an appropriate regulatory framework.

13. Free water


First, adequate water, like the air we breathe, is a basic human right and it should be free. The water that falls on the roofs of our houses and the land we own or lease should belong to those who own that title or lease. This local rainwater can be caught and used free of charge. But only what falls naturally on that land. What runs on from neighbours’ land and what runs off into other neighbours’ land is a common good that will be described in the next section.

It is important to remember this right is subject to the natural variability of rainfall as it occurs in the country. There is no certainty here, nor privilege. We all share responsibility for working within the natural variability of our climate and managing the water sustainably to which we have a right. The best way to even out uncertainties is to store this water in good times. In urban areas this might involve re-introducing rainwater tanks (including underground and above ground tanks and tanks incorporated into buildings to provide thermal mass). In rural areas, the best place to store water is in the soil. This involves building up soil structure through the replacement of lost organic matter. Although this water is a free good, those who wish to harvest and market their surpluses could do so, but they would be limited to what actually falls on their land in any one period. They have no right to what runs on and what runs off.

Soil based storage for rainwater is the most economic and provides a further incentive for maintaining and where possible improving soil structure. It maintains the natural water balance and minimises the additional amount of water needed to get plants and crops through dry times. Most importantly, as soil moisture slowly seeps away it takes with it the damaging salts that excessive watering bring to the surface. Maintaining soil moisture at natural levels is fundamental to sustainability and eco-system health. Landholders, having been provided with rights over their land by civil society and given the right to harvest the rain that falls on it, have a responsibility to maintain appropriate levels of soil moisture.

In addition to the natural storage of water in soils, I argue that catching some or all of the rain water that falls on an area either in water tanks or farm dams is a legitimate right of the land holder and it too should be absolutely free. The captured water can then be used for domestic, gardening or irrigation purposes and after suitable treatment discharged into the soil where it would have finished up if it had not been intercepted in the first place.

Three sets of circumstances need to be provided for in making the basic rainfall a freely accessible good. The first is where additional water is brought in over and above what can naturally be discharged into the soil and the second, where the land is so covered with impervious surfaces that soils are deprived of moisture and run off is increased. The third possibility is a combination of the two. These three scenarios will be dealt with after we consider run-off waters.

14. Run-off waters

As indicated above, surface waters that run onto private land should be considered a common good. They do not belong to the land-holder in contrast with run-off arising solely within the property boundary which, as we have seen above, should belong to the land-holder. Run-off that leaves property boundaries accumulates in creeks, rivers and surface flooding to provide the environmental flows needed to maintain healthy river and aquifer systems. In the past, State Governments have given some land holders rights to these run-off waters by allowing direct pumping from rivers and bores and the building of large dams that entrap flood and run-off waters arising outside their property boundaries. This is the privatization of an essential public good. It is generally agreed that the rights allocated in this way exceed the available supply and are inequitable between upstream and downstream users.

There is ongoing debate about the best way to address what is essentially an inequitable situation all round and is reminiscent of the way squatting practices needed to be addressed in the nineteenth century through reclamation and reallocation. Possible solution depends on the adoption of a pricing policy for the sale of water made available through more regulated processes: the large publicly owned dams.

15. Impounded waters

Waters from Australia’s large storage dams are provided at a charge (usually below cost) to householders, industry and agriculture through a plethora of publicly owned corporations and semi-corporations. In general, all these authorities are in the business of selling water and their financial health depends on selling as much as possible.

This is a huge issue when water is plentiful as it leads to overconsumption and, as we have seen, massive leakages into ground water. Overconsumption of water is a major cause of salinity.

It is also a huge issue in times of water shortage. Then it becomes necessary to impose water restrictions. These are politically unpopular, they hurt businesses and the water corporations financially and most importantly, they hurt the end users who cannot get enough water to do what they reasonably expect to do. These costs flow through to the whole economy. We might accept this as an inevitable consequence of drought, but to do so would be unwise because it means that we are ignoring an opportunity to modify our system to make it better. We cannot drought proof the country, but through clever system design, we can drought proof the economy.

Smaller scale locally managed autonomous water systems will progressively address some of these problems, but it is suggested a new basis for pricing will reverse the problem of overconsumption, level out variability of supply and eliminate under pricing in rather more immediate and less painful ways.

16. Water pricing policy

We now know very precisely the minimal water requirements of various households, crop species and industrial systems. These minima are not based on present delivery systems which include leaky pipes, enhanced (polluted) run-offs, flood irrigation and other wasteful practices, but what is needed in ideal circumstances. Fixing the distribution and delivery systems is a technical challenge and business opportunity that our pricing policy should encourage. At present, pricing policies encourage the rundown of infrastructure and passing on costs to future generations. Realistic prices for potable water will also encourage water reuse for industrial and agricultural purposes where potable water is not necessary.

It is suggested that households, businesses and farms that:

• install autonomous water systems be given a reduction in their annual land rates. Those that cover their surfaces with impervious material should pay an increase in their land rates in proportion to the area covered

• are linked into publicly provided water, be provided with the minimum levels appropriate to their household size, crop type and business activity free of charge. This quantity of free water is designed to stimulate activities within these minimal water limits

• use in excess of these minimal amounts be charged at rates that meet the pro-rata operating costs of the current system. These are punitive rates that will reduce overconsumption, and stimulate efficient water delivery. They will encourage people to move to autonomous systems as soon as practical.

There are two political issues that need to be faced when considering the above water pricing suggestions. First is the fact that people have been given more water rights than the available supply of water, especially in dry periods. Second the price of water does not reflect its true costs: it is too cheap and this leads to overconsumption.

The over-allocation of water rights has many features in common with the way land rights were allocated in the nineteenth century. Then a plethora of different titles were created to meet a range of expediencies such as dealing with illegal squatting practices, rewarding services rendered, compensation, making land available for purchase by free settlers, rewarding returned soldiers, opening up the country and so on. As is now well known, Australian land titles were based on a false assumption of terra nullius. At the time of first European settlement, ownership of Australia was vested in the Crown and people were given certain rights to it. They did not own the land, they owned a title which had various rights and restrictions associated with it (pastoral, mining, residential, industrial and so on). These titles are tradable. Many land related rights are over-lapping, that is to say, the same piece of land might include pastoral, mining and native title rights allocated to different people or groups of people. Native title rights are special in that they pre-exist the terra nullius assumption. They may be extinguished by the allocation of other kinds of rights and where they continue to exist, they are not tradable.

The land reforms of the 1860s went some way to addressing the mess colonial governments created. Subsequently the introduction of Torrens titles greatly simplified conveyancing transactions, in the 1980s native title rights were given some belated recognition. In recent years, a process of simplification of the plethora of special purpose titles (whether freehold or subject to annual land rents, whether temporary or permanent) has begun. For example, the NSW government passed legislation to reduce the 60 or so different sorts of title within its jurisdiction to a more manageable number. So far it has taken Australia 150 years to sort out its land title system and it is still a work in progress.

Unlike land that is for all intents and purposes fixed, available water is variable. The allocation of rights based on fixed amounts of water then makes no sense. The allocation of rights to a proportion of the available water is one way around this difficulty, but this creates disputes about the actual levels of available water. This is a further source of uncertainty. Not only is there uncertainty about actual rainfall, there are also uncertainties associated with decisions by water authorities as to the amounts and timing of water to be released from storage.

Uncertainty is a fact of life in a country of such climatic variability as Australia and it is likely to become even more variable with climate change. The resulting increased risks need to be managed in some sort of fair and reasonable way. Tying water rights to rainfall falling within the property boundary (as suggested above) can do this simply, efficiently and directly. It will provide a powerful incent-ive for every landholder to manage his or her water as efficiently as possible to minimize their own risks.

Modern small-scale autonomous water systems can be fine tuned to meet particular requirements at the farm, business, small community and even household level. They can utilize the same volume of water several times over thereby buffering the risks associated with rainfall variations and avoid the uncertainties resulting from decision by external water managers.

Standard economic theory and virtually every commentator on water points out that water is too cheap. If water was priced at or near its real costs, the argument goes, there would be huge incentives to use water more efficiently.

No one doubts that this strategy is sound. The political reality is however that no government could survive if they raised the price of water to cover the actual costs. And even if they did it, the flow on effects for the community in terms of increased food and other prices would be very damaging to the economy as a whole and make Australian primary production dependent on irrigation waters uncompetitive.

The above proposal - to provide a basic minimum of water based on the needs of the crop, not the delivery system - ensures a minimum and equitable level of subsidy to all growers. The very high prices charged for water above these minima will provide a powerful incentive for water efficiency and reuse.

Managed in this pragmatic way, a combination of price signals and subsidies will maintain a viable food production capacity.

It is important to remember that trading in water under these proposals would continue. People could purchase water at market prices from whoever is prepared to sell. What would stop is speculative trading in water rights as governments progressively and compulsorily acquire on the same “just compensation” basis as they do when sorting out land title issues.

If pricing policies along these lines are adopted, overconsumption will be reduced, productivity increased and most importantly, leakages from the system (the cause of salinity) will be eliminated.

Australia is in a unique position globally because of the poor quality of its soils and the variability of its water supplies. It needs to develop approaches to the supply and delivery of water that responds to those needs. In the nineteenth century, autonomous water systems were the norm. During the twentieth century, when we were caught up in the hubris of big scale development, we learned that these are not necessarily better and bring in a lot of very serious problems: none more serious than salinity which threatens our food security and long term economic well being.

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