Note: Where available, the PDF/Word icon below is provided to view the complete and fully formatted document
 Download PDFDownload PDF 

Previous Fragment    Next Fragment
Management of the Murray-Darling Basin system

CHAIR —I welcome Dr Kerri Muller. Do you have any comments to make on the capacity in which you appear?

Dr Muller —I am a principal of my own consulting company. I am a consulting ecologist, and my business is called Kerri Muller NRM.

CHAIR —Thank you, Dr Muller. You have seen that time is very constrained today. Do you wish to make a very brief opening statement? We will then go to questions.

Dr Muller —I will make a very brief opening statement. I would like to focus on the issue of flooding the lakes with sea water. I believe that that would be extremely detrimental to the ecology of the system, as well as to the socioeconomic assets of the area. The lakes have been freshwater for 7,000 years before European settlement of this country. I believe that they should stay as freshwater systems and I believe that letting in sea water will not prevent acidification of the lakes and is likely to exacerbate that situation.

CHAIR —Thank you, Dr Muller.

Senator HUTCHINS —Dr Muller, yesterday we heard from a number of respected experts who do not agree with your position. They believe that, if something is not done very quickly, these lakes will acidify. I think that is the exact term. What is your response to those experts? They are wrong and you are right?

Dr Muller —No. What I am saying is that the biogeochemistry—so the interaction between biology and geology and chemistry—of the lakes is extremely complicated. We do not really know what happens when a lake like this becomes acidified. We have never seen it before. What we are seeing is the accumulation—

Senator HUTCHINS —Then why should we let it happen now? If we can prevent it, why should we let it happen now? Just for some experiment?

Dr Muller —What I am saying to you is that the best option for preventing acidification is fresh water. Sea water contains sulfate ions. Sulfate ions are the precursor to sulfuric acid. We have a very small tidal signal at the barrages of 20 centimetres. The sea water will not adequately flush in and out of the lakes. Therefore, sulfate will be brought into the system, which will be converted to sulfuric acid. Sea water may neutralise the existing acid for short periods of time in the areas that it can actually get to.

Without some sort of physical intervention, it will not reach most of the hot spots within the lake. I am talking about acid hot spots, particularly around Point Sturt and the Poltalloch Plains. It is not going to reach any of those areas, particularly now that Lake Albert has been disconnected, so I do not believe that it will be the magic bullet that people are looking for. I think that the sulfate in the sea water is more of a risk than the bicarbonate which will neutralise the acid that exists there. It is an exceptionally complicated biogeochemical cycle that we are talking about.

Senator HUTCHINS —What is one of your solutions?

Dr Muller —I believe that the best option is to bring down the river. I understand that there is very little water in storage at the moment, but I do not think that we have any options. As has been indicated, if we let in the sea, we need to have 350 gigalitres going over lock 1 as a positive flow anyway. I think that we are in a position where we need to bring water down the river, probably in the order of 350 gigalitres over spring and summer of dilution flow.

Senator HUTCHINS —How do you propose to bring this water down the river? What is your solution? Is it the purchase of these temporary water rights, or whatever they are called? Is that one solution?

Dr Muller —We need to have real water. We do not need to just buy paper.

Senator HUTCHINS —I could say that too, but we are dealing with a very difficult issue here.

Dr Muller —I understand that.

Senator HUTCHINS —Experts in this field have also challenged what you have put to us here today. Okay, I understand that there can be difficulties there, but is purchasing water on temporary markets one of your solutions to this current difficulty?

Dr Muller —I am not an expert in water markets and I have not made any statements on that. I do believe that the eastern Mount Lofty Ranges is a resource that needs to be looked at seriously. There are five tributaries of Lake Alexandrina. They are capable of putting up to 120 gigalitres into the system in a wet year, and they certainly have contributed this year. The lakes now are at about minus 0.3 metres AHD, and that is greatly attributable to the eastern Mount Lofty Ranges tributaries providing water to that area.

I think we have to accept that there is going to be socioeconomic adjustment throughout the entire Murray-Darling Basin. I do not think that it is wise to allow farmers to go broke slowly because we cannot provide them with water. We have to accept the fact that we cannot provide water to all users in the system, and I believe that the most important user is the environment, because we rely on ecosystem services for our continued existence in the Murray-Darling Basin.

Senator HUTCHINS —Where is the city of Adelaide in your solution?

Dr Muller —The city of Adelaide is going to need alternative water supplies to the Murray. I think that is evident. Being reliant upon the lowest reach in the Murray-Darling Basin is an extremely risky position, and it always has been, for Adelaide’s water supply since it has been taken from the Murray.

There are significant options other than river water for Adelaide. I do not believe that desalinisation is a very wise option because of the issues with discharging effluent into the gulf. The gulf is not an oceanic environment. It is a gulf environment and is very contained, and the release of that effluent is of great concern to me. I think that there are a lot of options for harvesting stormwater, particularly from house roofs before it becomes contaminated. I do not think that has been looked at enough, when you look at new developments that are about 85 per cent hard surface and can be tapped as virtual reservoirs.

CHAIR —Dr Muller, in Western Australian we have a desal plant and we are looking at another one, and the doomsayers were saying the world was going to cave in and that Cockburn Sound would collapse. That has not been the point. If water is not there, we have to do something.

Dr Muller —Yes, but you also have to—

CHAIR —Have you looked at Perth’s desal plant?

Dr Muller —appreciate that the Gulf of St Vincent is a negative estuary. There are very few negative estuaries anywhere in the world. That means that it is more saline towards the land than it is to the sea, so it has very little flushing capacity.

CHAIR —We had a lot of these same issues, Dr Muller, thrown to us in Perth. It is just as well we have it, too.

Senator FISHER —Dr Muller, you estimate, you have said, about 350 gigalitres are probably required. On what basis do you form that view? How much water is required to save the Lower Lakes and the Coorong?

Dr Muller —The absolute quantum of water varies depending on local climatic conditions, so on the water balance of the lakes themselves. I like to think of these things in terms of target levels. Our first target is to make sure that the lakes do not go below 80 centimetres below sea level because that will be the trigger point for acidification of the lakes, based on the modelling done by the University of Western Australia and other groups that are contracted through the South Australian Department for Environment and Heritage. So our first step is that we have to make sure the lakes at no point go 80 centimetres below sea level. We then need to have a target of getting them to sea level by spring 2010 and then getting them back up to an operable level between 30 and 60 centimetres above sea level, so the absolute quantums of water will vary. It is likely that we are looking at around 350 gigalitres per annum to recover that system but, as I say, that depends upon local climatic factors.

Senator FISHER —What happens if it rains or does not rain, and when?

Dr Muller —They are the local climatic factors that I am referring to.

Senator HEFFERNAN —If it does not rain next year, even Albury will be in trouble. So you will spend all that water, which is next year’s high-priority water, so then the human factor becomes a problem. There is no assumption that it is going to rain next year.

Dr Muller —I am not making that assumption.

Senator HEFFERNAN —You are, because if you put that water into that system for that purpose, there is absolutely no reserve for human needs.

Dr Muller —There was a question put before about Menindee Lakes and the requirements of Broken Hill. Broken Hill requires 12 gigalitres of water and 350 gigalitres are held in storage. There are other options for delivering water to Broken Hill.

Senator FISHER —Have you had a look at the federal department’s submission on this to this inquiry and their covering of those options?

Dr Muller —No, I have not.

Senator FISHER —You might take on notice and provide to the committee your assessment of the department’s submission and in particular their covering of the Menindee Lakes issues, where they suggest that, as you say, significant numbers of gigalitres are needed to be kept in reserve to provide for both Broken Hill and critical human needs for Adelaide.

Dr Muller —Yes.

Senator FISHER —It may well be that most of that evaporates anyway.

Dr Muller —That is correct.

Senator FISHER —With regard to the Lower Lakes versus the Coorong—I understand there are differing salinity levels between the two—the department’s submission does not go to any differing options. It treats them both as the same. In your expert opinion, are they the same or are there options that may exist for one and/or the other that might be different?

Dr Muller —They are different systems, although they are obviously very interconnected. The lakes are dependent upon the River Murray and tributaries of the eastern Mount Lofty Ranges for their water supply as well as groundwater that comes in from the region. That will influence the north lagoon down to say 40 kilometres from the Murray mouth to about Parnka Point. The southern end of the Coorong is unlikely to be significantly improved by River Murray flows and will require some other options. It is likely that the southern lagoon of the Coorong will need some sort of intervention such as pumping to reduce its salinity and will then need to be refilled with fresher water.

There are some options to recover water from the south-east of South Australia. Wetlands such as Piccaninnie Ponds are currently draining to the ocean. That is not a natural situation. Those wetlands should be contained and should be flowing back towards the Coorong. I understand that the South Australian Department for Environment and Heritage have looked at the feasibility of bringing that water back and are currently looking at the volumes of water, how much could be delivered and what sorts of impacts it would have on the southern lagoon salinities. They are different sorts of systems and they require water in different ways.

Senator FISHER —If you have further comments on that, you might provide them to the committee at a later time.

Dr Muller —Indeed.

Senator FISHER —My colleague Senator Nash has a question.

Senator NASH —I just have one quick one.

Dr Muller —Can I just make one point: that the Ramsar management plan that we have just submitted to the South Australian DEH has a lot of those in it. It is only a draft document at this stage, though.

CHAIR —Senator Nash, I know you have been waiting patiently. There are others on the speaking list first, but I know Senator Nash will be brief, so Senator Nash first.

Senator NASH —I will indeed. You mentioned earlier, Dr Muller, that your view was that the most important user of the water was the environment. I would also put that food security and feeding the nation are right up there as well.

Dr Muller —Absolutely.

Senator NASH —You were talking about having to bring water down even though you could not say how or how much. Have you done any work on a quantum amount of how much, and have you done any work on the effect that removing that water from upstream will have on food production?

Dr Muller —I appreciate that food security is a major issue for this country. I also appreciate that ecosystem services are the way that we produce food. We cannot produce—

Senator NASH —We are short of time. Could you just answer the question.

Dr Muller —I am getting to your question. I have already stated that my expertise is not in understanding water markets or how to get the water. My expertise has been focusing on what to do with the water at this side.

Senator NASH —True, but my question was specifically around whether you have done any work on the capacity for food production if you take the water out?

Dr Muller —No.

Senator SIEWERT —It is important that we articulate here that, as you said, your expertise is in the ecological understanding of these wetlands and that is what you have been providing advice on.

Dr Muller —Correct.

Senator SIEWERT —I presume you tell others how much water is required to keep those functioning.

Dr Muller —That is correct.

Senator SIEWERT —And you do not have expertise in agricultural science.

Dr Muller —No.

Senator SIEWERT —So it is not your area to say how we would grow food.

Dr Muller —That is correct.

Senator SIEWERT —It is important that we get that on the table. The issue was raised with us yesterday by Dr Phillips. He was mentioning the wetlands when we were talking about the health of the system and water. He was talking about some of the other wetlands along the river and potentially getting some of the water from there and putting that into the Coorong. What is your opinion of that in terms of whether it is ecologically sustainable in the short term?

Dr Muller —I believe that many wetlands throughout the Murray-Darling Basin are in a degraded state. Acid sulfate soils are affecting thousands of wetlands across the basin and are likely to affect some of the tributaries such as the Edwards and the Wakool, so in answering that question you would have to look at the wetlands from which you are taking water to determine whether it is ecologically sustainable to do that. That said, the river did work before European settlement of this country and it did provide water to all of the wetlands in just about every year, so there are ways in which water can be utilised ecologically throughout the basin in a stepwise process so that water can be green to the sea and can be used throughout the catchment for multiple ecological benefits.

It is hard to answer that question without understanding specificities about the wetlands from which the water would be taken, but I believe you need to take a risk management approach to these things. It is critical that we maintain the ecosystem services of our wetlands and our genetic diversity, particularly coming into climate change. We need to improve the resilience of our ecosystems to changes such as climate changes. It is something that we do have to look at: sharing water between wetlands but making sure that ecological processes and functionality are occurring at all levels. As a risk management approach, you would deal with the things that are about to fall over first, and the Coorong and lakes are certainly about to fall over.

Senator SIEWERT —You mentioned the management plan that you and, as I understand it, Dr Phillips have been working on.

Dr Muller —That is correct.

Senator SIEWERT —He mentioned that in his evidence yesterday. Obviously it is a draft, so we have not seen it. But are these the sorts of issues that you have canvassed in that management plan?

Dr Muller —That management plan focuses on the Coorong and lakes. It is not a whole-of-basin water management plan. I believe that a whole-of-basin plan for environmental flows is something that is required. If we do that, we will see that we can get multiple benefits from one package of water. The plan I am referring to is site specific. It is for the Coorong and lakes. It looks at volumes of water that are required to recover the ecological character of that site and how to use the water within the site. It does not look at delivery to the site.

Senator SIEWERT —When you talk about the 350 gigalitres that are required, that is canvassed in the plan?

Dr Muller —Yes.

Senator SIEWERT —What are the other key elements that you are suggesting there need to be for the management of the river?

Dr Muller —It focuses on recovering the lakes to sea level and then operating them at a lower level than the one at which they were operated prior to 2000, so we would be looking at operating them between 0.3 metres and 0.6 metres rather than surcharging them to 0.8 metres. That would represent savings from the regular operation, although the lake has not been at 0.8 metres now for several years.

CHAIR —Sorry, Senator Siewert, I would ask if that can be ended.

Senator SIEWERT —I was just asking if—

CHAIR —Just before you jump off the deep end, could you make this your last one and then I can move to Senator Xenophon and then others. So, please, instead of wasting time, ask the question.

Senator SIEWERT —And I know Senator Hanson-Young has a question, so I was going to put a question on notice.

CHAIR —Okay.

Senator SIEWERT —Could you provide us with some information about what else could be done around acidification of the lakes if we were not using sea water.

Dr Muller —Yes. In particular we could look at bioremediation, so using plants and mulch, and I have put that in my submission to the Senate.

Senator SIEWERT —We have only just got it, so I have not had a chance to read it.

Dr Muller —I know. I appreciate that.

Senator SIEWERT —If that does not answer my questions, I might seek to put some more on notice.

Dr Muller —Yes. There are trials that will be beginning in the next four weeks, looking at bioremediation, so using plants and mulch to deal with acidification, which is a far preferable situation to letting in the sea, because the sea will be irreversible, whereas planting around the lakes and using mulch is a way of dealing with the acid that does not require water.

Senator HANSON-YOUNG —Dr Muller, could you just flesh out a bit more about the nomination of wetlands in South Australia that perhaps, if they were redirected to the river system, would contribute to freshwater flows for Lake Alexandrina and Lake Albert.

Dr Muller —You are talking about wetlands within South Australia that have water in them?

Senator HANSON-YOUNG —Yes.

Dr Muller —There are not very many of them left. Most of them have been disconnected from the river.

Senator HANSON-YOUNG —Yes. Even out of those that have been disconnected. You mentioned that some of these wetlands are actually flowing out to sea at the moment.

Dr Muller —That is in the south-east of South Australia. We are talking around Kingston and Robe, so not wetlands within the Murray-Darling Basin. These are wetlands in the adjoining catchment which, again, prior to European settlement was connected to the south end of the south lagoon.

Senator HANSON-YOUNG —How easy do you think it would be to redirect that water?

Dr Muller —Actually stopping the water going out to sea would be relatively easy because they all have man-made drains cut out to sea. The issue then is of actually getting the water across the landscape back to the south lagoon, and I understand that that has been investigated.

Senator HANSON-YOUNG —And do we have any—

CHAIR —Sorry, Senator Hanson-Young, I am going to go to Senator Xenophon. If there is any other time left, we can do the rounds again.

Senator XENOPHON —Thanks, Mr Chair. Yesterday Dr Phillips in the evidence that he gave made reference to almost a doomsday scenario of flooding the lakes with sea water, but then said that there was a real risk that doing that could contaminate the groundwater in the Lower Fleurieu. What is your knowledge of that? Is it backed up by other scientific evidence? And has it been robustly looked at in terms of worst-case scenarios?

Dr Muller —We know that the eastern Mount Lofty Ranges and the lakes are connected through groundwater. We know that the head levels of the groundwater are dropping because of the lakes having dropped. There are hydrological investigations going on currently because the eastern Mount Lofty Ranges are going through the prescription process so there need to be those studies to determine water allocations for those catchments. What we do not understand is how the salt may move through the aquifers that feed the EPBC-listed wetlands at the bottom of Currency Creek, Tookayerta Creek and the Finniss River. I believe that that is a significant knowledge gap. We do know that the neutralising capacity of the groundwater under the lakes has reduced; therefore, acid is moving into the groundwater and is consuming some of that neutralising capacity. So there is a real risk that, if the sea was let into the lakes without positive flow coming down the river, it would enter at least Currency Creek, and possibly Tookayerta, and they are peat based systems, so once salt gets in there the structure of the sediments will change and they will rapidly erode and we are likely to lose our EPBC-listed wetlands.

Senator HURLEY —You would know that the Australian government has committed $120 million to provide the Lower Lakes with alternative water supplies and $200 million towards a lasting solution for the environmental problems of the Lower Lakes and the Coorong. Given that these acidification risks that we have been talking about apply not only to this site but in the southern Murray-Darling Basin, what is your plan to comprehensively address the acidification problems?

Dr Muller —With acid sulfate soils, there are best practice guidelines that we understand very well: you do not disturb them; you do not add fresh sulfate; you keep them wet, if at all possible; and you prevent the ingress of more carbon into the system. I think we need to look at those fundamental principles. I think we need to look at waterless solutions such as bioremediation through planting and mulching. The beauty of that is that, as the wetlands refill, the heavy metal salts that have been generated through the acid exposure will get absorbed to a certain extent and will not be mobilised into the surrounding environment and into potable supplies.

I think it has to be a multipronged approach. We need to look at things like revegetation and mulching to start with and then we need to have secure environmental allocations that are there to refill these wetlands in a structured way and make sure that we recover them, because once acidification occurs it will be effectively irreversible if it occurs to the extent that it has in areas like Bottle Bend wetland near Mildura. We do have examples of wetlands that have tipped over too far and we cannot afford for that to happen across the basin. So I think we have to start with bioremediation, because we are in a situation where we have very little water, but then we do have to recognise that this is a very high priority for water within the basin.

Senator HURLEY —So this $200 million will kick off that kind of work.

Dr Muller —Yes.

Senator HURLEY —And help buffer the area against future problems.

Dr Muller —If it is spent wisely, indeed. There may be some wetlands that could benefit from liming. That, unfortunately, is not an option for the lakes Alexandrina and Albert because of the size of the wetlands and because the sediment is very unstable and you are unable to get farming machinery onto it to lime it, but liming could be an option for some other wetlands. There may be other options in terms of pumping small amounts of water over them before they reconnect to the river to neutralise the acid, and also, if you do that in combination with mulching, you can deal with the heavy metal load. I am concerned about the heavy metal load getting into potable supplies. It is typical for water treatment companies to use products such as alum to flocculate sediments out of the water, and if the heavy metal concentrations go up too high they will not be able to use those products, so there is a real risk to our potable water supplies from heavy metals coming out of those wetlands and into the river system. I think we do have to look at bioremediation as a very first option.

Senator HEFFERNAN —Thank you for your expertise, for which we are grateful. I would like to bring you to the salinisation of the aquifer. That will only happen, won’t it, if there is a negative head?

Dr Muller —No, because there will be recharging of the groundwater with sea water. Is that what you are referring to: if the sea water is let into the lakes?

Senator HEFFERNAN —It depends what is drawn out of the aquifer to get the salinisation. There will have to be management of the extraction as part of the strategy, surely.

Dr Muller —Yes, absolutely. There would have to be management of the extraction of groundwater, but the connectivity between the lake and the groundwater is highly variable, depending on the sediments underneath the lakes. There are areas where there will be recharge even at sea level.

Senator HEFFERNAN —If we use between 700 and 900 gigs to freshwater the lakes and the snow does not melt this year and next year is dry, what are we going to do about Adelaide?

Dr Muller —I think we have already discussed that Adelaide needs to wean itself off the River Murray.

Senator HEFFERNAN —No, this is next year.

Dr Muller —This is next year?

Senator HEFFERNAN —It is a fantasy. Do you think we should take the sovereign risk that you are presenting to the committee?

Dr Muller —I think that we have to weigh up—

Senator HEFFERNAN —The snow did not melt last year. Let’s deal with the facts.

Dr Muller —Yes, I do appreciate what you are saying. What I do not have in front of me is a comprehensive water audit for the basin, so I do not know what risks I am actually playing off against each other.

Senator NASH —Isn’t that dangerous?

Senator HEFFERNAN —That is the dilemma that we face, you see. We need to get all this onto one database and, because we have got a table-wide of senators here today and only so much time to put everyone through the drill, we are not getting anywhere.

Dr Muller —Indeed.

Senator HURLEY —We have discussed to some extent weaning Adelaide off the Murray. By when should that happen?

Dr Muller —It is a situation that needs to occur immediately. We know that the lower reach of the Murray is—

Senator FISHER —What do you mean by ‘immediately’?

Dr Muller —There have been extensive looks at the aquifer. I know that when Peter Cullen was thinker-in-residence he looked at the capacity for the aquifers to provide water. The problem there is contamination. Desalinisation, as I have said, has the issues to do with effluent disposal. That is something that could happen quickly but it needs to look at the effluent disposal.

The problem though, of course, is that water is delivered from the hills to the sea and desalinisation and stormwater treatment both occur at the sea and then would need to come back up to the hills. The time frame is not something I have an expertise in understanding, but I do believe that it is something that we need to move on immediately.

Senator FISHER —Given your areas of interest, what do you think of a city like Adelaide being given critical human needs to draw from the Murray-Darling Basin when we are not even on the Murray? We are the capital city that relies on it for the majority of our water supply in any given year, up to 80 per cent. What do you think of that, given your expertise and area of interest in saving the Coorong and Lower Lakes?

Dr Muller —Our natural heritage has to come first. Our wetlands cannot be lost.

Senator FISHER —Before critical human needs?

Dr Muller —We need to have a much better understanding of what critical human needs are—

Senator FISHER —Agreed.

Dr Muller —and how little water Adelaide can actually run on without causing human health issues.

CHAIR —Thank you very much, Dr Muller, for your submission today and for appearing.

[10.01 am]