The drought we had to have?

There is increasing rhetoric coming from politicians and bureaucrats about the plight of the Murray-Darling Basin. As a river ecologist, it sticks in one’s throat somewhat.  Chief Executive Officer of the MDBC, Dr Wendy Craik, has described the Murray River as “being on life support”.  As far as I am concerned, over the past 100 years the river has been getting increasingly sicker and been in a coma for several decades. What this current drought has done is bring into sharp focus the problems that the rivers – and we, as participants and beneficiaries in its ecology – face.

If we think we are facing climate change now then consider that our rivers – and the animals and plants that live in them - have been exposed to massive climate change for more than 100 years.  No wonder they have been struggling.  The first serious weir, designed for irrigation, went in the Goulburn River, Northern Victoria, in 1890.  Since then thousands of dams have been built. The most well known and one of the biggest, is Lake Hume, at the upper end of the Murray, which was finished in 1936 and therefore has been operating now for more than 70 years.  The typical large dam captures runoff in winter and spring, holding it until the growing season and warmer weather gets underway, and then releases it downstream.  This results in a reversal of the flow regime: where naturally it would have been high in winter and low in summer, it is now low in winter and high in summer.  Many of our large dams also have bottom releases.  Large bodies of water become stratified -  with cold water sinking to the bottom and warm water floating on top. Consequently  the water that is released is considerably colder than it would have been naturally.  The water can be more than 10 oC cooler downstream of a dam than in a nearby un-dammed river.  And since most of the animals that live in rivers are cold-blooded, they are seriously affected by this ‘thermal pollution’: reproduction and growth are intrinsically tied to water temperature in many species.  Imagine living in your natural environment one minute, and then the next, the medium in which you live is in short supply when normally it is abundant, and is plentiful when it is usually limited.  And furthermore, that in summer it now rarely gets above 16 oC when once it reached close to 30 oC. Now that’s climate change!

You see, it is not just the lack of water that is the problem.  Too much of it, and at the wrong time, can be equally as lethal.  Animals and plants that have evolved to take cues from the environment have had their world turned upside down. There are many, many examples of their demise.  Add to this the fact that introduced species, like carp, European perch, trout and the plague minnow Gambusia, are superbly adapted to take advantage of these altered conditions. Insult is added to injury.  And don’t forget over-fishing of our large fish species (which started in the mid-1800s); excess nutrient inputs into rivers; and past practices of bankside and instream habitat destruction.

There have been signs for decades that the situation in the Murray (and many, many other rivers as well) is not sustainable, and to give credit where it is due, some farmers, river scientists, and state water , catchment  and natural resource management agencies as well as federal bodies like the Murray-Darling Basin Commission have been working to try to ameliorate these problems for some time.  But they have been hampered, in my opinion, by several factors which have led to tinkering at the edges and pussy-footing decision-making rather than taking serious, hard, uncomfortable, but ultimately inevitable, decisions.  The factors are: an existing irrigation infrastructure and mindset; a paradigm of economics-will-solve-everything attitude; and a lack of basic knowledge about how our river ecosystems function.

The late Gaylord Simpson, ex US senator and Governor of Wisconsin, said that “the economy is a wholly-owned subsidiary of the environment”.  Economies are not ultimately sustainable unless the environment, on which they intrinsically rely, are sustainable.  If the environment is not sustainable, then the environmental capital being used up and not replaced will eventually dwindle away to nothing.  This can effectively be ignored in the excitement of making money and hay while the sun shines and the rivers flow, until serious environmental disasters occur  such as a drought or looming climate change.  But when a whole system has been built to attempt to create certainty and stability in an intrinsically uncertain and unstable water environment – like most of Australia and especially the Murray-Darling Basin - there will be a crunch time for users of water.  It is probably that time now.  Unfortunately, the crunch time for riverine animals and plants happened many decades ago.  The only answer is to change - and change dramatically - what we do and how we do it.  Otherwise, as many predictions outline, we will have little left to do anything with.  The Murray-Darling Basin may be as good as useless for agriculture by the end of this century if current predictions are borne out.  But what about the biota?  Does this rate even a mention?

We have, over the last few decades, moved further and further into the paradigm of everything having a price (not necessarily a value) and letting the market decide how much water is worth and where it goes.  This sounded like a good idea at the time, but I think the environment has been the loser in the equation.  In this paradigm, the environment becomes just another user, or worse, client, and when it needs more water, it – the government, or us, actually – has to pay for it.  It would seem logical to give a substance absolutely critical to maintaining the function of a system, upon which other systems are based, the highest priority.  Instead, we have put it on level footing with other users, which might be fine if we knew how much water was needed (and when) to maintain that functioning system.  But we don’t!  And we probably won’t for many decades.  Which means we will, for a long time to come, be flying blind and making mistakes as we try to ‘manage’ an incredibly complex system with an ignorance that is startlingly profound.  

That is why I called this piece “The drought we had to have”.  Perhaps it and climate change are a blessing in disguise.  Perhaps it has meant that we will now, at long last, have to face up to the serious problems that have been here for a long time, but have been obscured by copious amounts of turbid water barreling down our rivers.  While I am always hopeful of a change in attitude – and now is the time for it - I fear, however, that we, as always, will focus on our own human-centred concerns, and that the organisms that live in rivers will have to make do with what is left over.  

Dr Paul Humphries is a marine ecologist with Charles Sturt University’s Institute for Land, Water and Society.


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