Back to All News

Question to the Murray Darling Basin Authority

Senator HANSON-YOUNG: You were talking just then about the scientific peer review. Did the Wentworth group of scientists directly ask for a specific independent scientific reference panel and for the authority to facilitate that?

Mr Freeman: Yes, they have.

Senator HANSON-YOUNG: What has been the response from the authority?

Mr Freeman: The authority has neither rejected nor confirmed that. At this stage, the authority is keen to get independent advice on the integration of its science, as I indicated before. All of the elements of the science have been peer-reviewed. Has that been put together in the most scientifically robust way is the question we are now asking. Depending on the response to that issue, the authority will then determine the next step as to whether it needs a further independent review or we are satisfied with the-

Senator HANSON-YOUNG: So you have not rejected the request, but you have not fulfilled it either?

Mr Freeman: That is correct.

Senator HANSON-YOUNG: How does the authority expect to meet the requirements of the Water Act to apply the best available science if there is not some type of overall review of the science that is being used? I understand your point about individual peer analysis, but this is an integrated system and the argument is that there needs to be a review of how all of this stuff fits together and the impact that will have. How would you apply the requirement of using the best available science if you do not have something as overarching as that? Wednesday, 25 May 2011 Senate Page 72 ENVIRONMENT AND COMMUNICATIONS LEGISLATION COMMITTEE

Mr Freeman: The authority is keen to have that overarching review. That is actually the issue for the science forum. The science forum, which the Wentworth group chose not to participate in-and that is their right-has essentially come back with questions. We need to better explain our overarching methodology and framework. They have confirmed that the individual scientific elements appear to be the best available, but they would like a further explanation as to how this overarching framework all fits together. We are dealing with something that is actually quite complex. Dr MacLeod was responding to Senator Joyce's questions-there could be an inference there that we just pick scenarios. We do not do that. We pick environmental objectives, we look at the water regimes that support those environmental objectives and that then goes through a model, which then generates a number. The number is an outcome; the number is not an input. So these so-called scenarios are actually about determining what the numbers might be at a catchment or basin scale. The integration of that on a basin wide basis is the issue that the science forum has come back to us on and said, ‘We do not fully comprehend your framework here and therefore we cannot comment on whether this all fits together in the most scientifically robust way. Can you please do more work on the explanation of this scientific framework.'

Senator HANSON-YOUNG: And the authority is prepared to do that?

Mr Freeman: We have been very actively pursuing that over the two weeks since the forum.

Senator BIRMINGHAM: And the science forum will meet again?

Mr Freeman: That is to be determined. I think that would be a logical outcome, but that is still to be determined.

Senator HANSON-YOUNG: At the recent forum, were scientists advised that the authority would be proposing a 2,800 gigalitre volume of return to the environment?

Mr Freeman: Again, I refer that question to Dr MacLeod, who was actually there. I noticed in some of the press releases that it was attributed to me-that I mentioned 2,800. I can reassure the committee that I never raised any number, let alone 2,800.

Senator HANSON-YOUNG: Did anybody from the authority?
Mr Freeman: I will refer that to Dr MacLeod, but certainly I did not raise the number, nor did anyone when I was present. But that was only for a short part of the actual forum.

Dr MacLeod: In response to the question, during the period of the forum we were exposing all of the different lines of evidence that are available to the authority, which presents a very wide variety of different outcomes in terms of numbers. During the course of that day, we did explore ranges of numbers which did include 2,800. There was the end of system flow analysis, which was presented in the guide, which has numbers in the region between 3,000 and 4,000. There is other work that has been presented, such as the work on the outcomes of the Living Murray, which gives different sets of numbers again. So, during the course of the day, we were presenting all of these different lines of evidence such that the science forum was better placed to understand how all of that had been brought together by the authority.

Senator HANSON-YOUNG: So you are suggesting that there was no proposal that a figure of 2,800 would be sufficient to deliver the outcomes as required under the act?


Dr McLeod: All of the proposals that we were exploring, as Mr Freeman has indicated, are all premised on identifying a series of environmental objectives and targets at a series of locations that meet the objects of the act. There is very wide variety of parameters that you can deal with in the basin to achieve those outcomes. Volume is not the sole issue at the heart of this. For example, the way in which you might run the rules that operate in terms of running the river itself are equally important in your ability to achieve outcomes. For example, the reregulation of environmental flows and the particular operating rules about individual pieces of infrastructure all have a role to play. At the other end of the spectrum there are the elements that are within the proposed basin plan, such as the proposals for a new environmental watering plan and water trading rules, also have a significant impact on your ability to meet various types of environmental outcomes. So we were presenting all of those elements during the course of the day.

Senator HANSON-YOUNG: I accept that, but that there are very specific outcomes required under the act. I would imagine that you would only be talking about an environmental return that would be sufficient for fulfilling those requirements under the act, otherwise what was the point of raising that type of figure?

Dr McLeod: The requirements under the act, as it is specified, are to provide an environmentally sustainable level of take that does not compromise key environmental assets, key consistent functions, productive base and key environmental outcomes. In respect of that, there is a significant opportunity to explore what that actually Wednesday, 25 May 2011 Senate Page 73 ENVIRONMENT AND COMMUNICATIONS LEGISLATION COMMITTEE
means. It is not a definitive, singular answer. There are many different perspectives on what constitutes protection or restoration of an individual asset.

Senator HANSON-YOUNG: Do you have any evidence that the 2,800 figure would fulfil the requirements under the Water Act?

Dr McLeod: All of the options and all of the discussions that we took the science forum, we believe, will provide for the provisions of the act.

Senator HANSON-YOUNG: What has been the change in the methodology used to justify that amount in comparison to what was illustrated in the draft guide, which clearly was much higher?

Mr Freeman: The difference is that I guess the authority is saying that the most robust answer would be a bottom-up build-what are the water requirements for 2,442 identified key environmental assets and the four functions that we have identified that we believe are critical for healthy, functioning river systems. That would be the most robust modelling exercise. Our estimate is that that would take probably in excess of five years. It is work that needs to be undertaken, but it is not going to be done in time for the basin plan. The basis of the guide was end of system flows. It is the least reliable of the three methodologies. I will talk about the second one. As Dr McLeod has indicated, it does not differentiate in the hydrology of the river. Essentially, it says that all parts of the profile, whether it is a wet part or dry part, are equally important and it just tries to mimic nature as much as possible. That was the basis of the guide. I think it is fair to say that, to the extent that there has been more precise asset modelling, end of system flows modelling, which is that methodology, tends to overstate environmental water requirements because it is actively trying to reinstate all parts of the profile. Miss Swirepik can talk about that in more detail as an ecological scientist. The third methodology, which is the science we are now running-we have had more time to do this; we have had the additional six months-is doing the detailed profiles for those 106 indicator sites. That is 88 function sites and 18 asset sites where we have actually fed in the detailed profiles for those and that is the science that is now starting to come out of the modelling. We believe you should not reject any of those. The end of system flows methodologies was the best available methodology. It is the basis of the Living Murray and the basis of everything that has preceded this. We are now in a place to actually put something better on the table. However, having said that, the authority is keen to reinforce that these are both valid lines of evidence and need to be both taken into account in making a judgment as to what the volume should be. So we have additional science now emerging.

Senator HANSON-YOUNG: What can you specify in terms of the modelled ecological impacts of a 2,800 gigalitre figure on the Lower Lakes and Coorong?

Mr Freeman: I have not participated in any of the modelling. I can comment about the 3,000 modelling, but Dr McLeod knows more about the 2,800.
Dr McLeod: In general terms, the way in which a scenario of 2,800 would apply would probably not have major differences in the Lower Lakes from a 3,000 scenario. In general terms, the 3,000 scenario would be providing positive flows to the ocean somewhere in the region of 90 per cent of years. I would generally look after the Lower Lakes in terms of the objectives that were being sought to be specified. Those objectives have been discussed at length with South Australia to try to ensure that they adequately reflect what has been the desired outcomes of the Lower Lakes. So, generally speaking, it would not have a significant difference at the Lower Lakes-it would be different outcomes at other parts of the basin but not necessarily at the Lower Lakes.

Senator HANSON-YOUNG: So you have considered this figure enough to be able to have done that modelling?
Dr McLeod: We have considered many numbers and that just happens to be one of them. We have been looking at updating the modelling to support any outcomes that will come from them.

Senator HANSON-YOUNG: I still struggle to hear confidence from you that that figure of 2,800 will fulfil the requirements under the current act to uphold all of the things that we need to do, to ensure there is environmental sustainability, to ensure that we protect those Ramsar listed areas. They are the specifics within the Water Act. I am hearing a lot about different models and different scenarios, but I am not hearing much assurance that you think that that figure will fulfil the requirements under the act


Back to All News