Lower Lakes Independent Science Review

The way the Lower Lakes in South Australia are managed is contested. There are differing opinions on their history, how they’re managed and whether anything needs to change.

The Murray-Darling Basin Authority initiated an independent review of the relevant science relating to the management of the Lower Lakes. In December last year, the MDBA asked ACSEES – the advisory committee to the MDBA – to manage the review. An independent panel – led by the CSIRO – has undertaken the review of the science.

Get involved

We understand there are many different perspectives, views and and we invite you to post your questions here for the experts.

The opportunity to post questions has now closed. All responses will be added to this site by Friday 22 May. Thank you to those who have taken an interest and posted questions (you will get an email to confirm when we answer your question).

Find out more

The Independent Review of Lower Lakes science informing water management considered hundreds of studies with input from almost 100 technical experts.

They addressed three key questions:

  1. What are the various scientific perspectives on the past and current hydrology and salinity of the Lower Lakes and how have the lakes come to be managed in the way they are?
  2. What would be the likely regional social, environmental and economic implications of removing the barrages, and would this result in significant water savings?
  3. What knowledge needs are required to plan for the main social, environmental and economic vulnerabilities of the Lower Lakes to climate change?


The way the Lower Lakes in South Australia are managed is contested. There are differing opinions on their history, how they’re managed and whether anything needs to change.

The Murray-Darling Basin Authority initiated an independent review of the relevant science relating to the management of the Lower Lakes. In December last year, the MDBA asked ACSEES – the advisory committee to the MDBA – to manage the review. An independent panel – led by the CSIRO – has undertaken the review of the science.

Get involved

We understand there are many different perspectives, views and and we invite you to post your questions here for the experts.

The opportunity to post questions has now closed. All responses will be added to this site by Friday 22 May. Thank you to those who have taken an interest and posted questions (you will get an email to confirm when we answer your question).

Find out more

The Independent Review of Lower Lakes science informing water management considered hundreds of studies with input from almost 100 technical experts.

They addressed three key questions:

  1. What are the various scientific perspectives on the past and current hydrology and salinity of the Lower Lakes and how have the lakes come to be managed in the way they are?
  2. What would be the likely regional social, environmental and economic implications of removing the barrages, and would this result in significant water savings?
  3. What knowledge needs are required to plan for the main social, environmental and economic vulnerabilities of the Lower Lakes to climate change?


This Q&A session has now closed. 

Ask your question here:

loader image
Didn't receive confirmation?
Seems like you are already registered, please provide the password. Forgot your password? Create a new one now.
  • I watched the presentation... I was actually a little disappointed because I it failed to answer the question that most critics of the current policy pose. If I can crudely summarise what I took from this morning’s presentation, it went something like this: • Pre-development the Lower Lakes were fresh most of the time (in itself this is an important piece of knowledge), and • the legislation says we need to keep them fresh (in my experience community members don’t take it well if you give the reason for doing something as – ‘the legislation says so’) • it takes less water to keep them fresh with the barrages in place, • therefore the science supports the current policy (but things are really going to go to pot as the climate changes). The argument that most critics of the current policy seem to be putting is: • keeping the Lower Lakes fresh takes an enormous amount of water, • the benefits of keeping the Lower Lakes fresh don’t justify the use of this much water. What I would like to know is details of how much water is required to keep the Lower Lakes fresh what would be the economic and ecological cost if there was a decision made to reduce the volume of water flowing into the Lower Lakes and therefore allow salinity to increase (I understand that there are a range of ways to manage that) what would be the upstream economic and environmental benefits of having access to water that previously was dedicated to maintaining the Lower Lakes. Essentially: what are the economic and ecological opportunity costs of the current policy?what does a cost benefit analysis of the current policy tell us? (I understand that the outcome of such an analysis will be greatly influenced by how ecological assets are valued). Personally I support the current policy, but underneath the misinformation and misplaced anger about the Lower Lakes are some valid questions which I would like to be able to answer.

    Tom M asked 6 months ago

    Thank you for watching the presentation and for sharing your summary.  

    One of the key points to emerge from the review is that the Lower Lakes cannot be managed in isolation.  The Review found that the water that passes through to the Lakes has been used to achieve environmental outcomes upstream and subsequently achieves environmental outcomes in the Coorong and Murray Mouth.  

    The evidence is that flows during the drought have been inadequate to achieve the key Mouth Open target and this, along with other threats from Climate Change will need to be addressed through work the SA Government and MDBA are currently planning.  

    See more about the Lower Lakes Independent Science Review including the full report with all the detailed information on the findings.

  • What estimates, modelled or otherwise, has the Science Review provided on the ecological productivity opportunities and resultant huge public benefits of restoration ecology - returning the Lower Lakes to be once again, Australia’s biggest estuary?……and if not, when can I assist the MDBA in designing such an assessment [which of course i will contribute pro bono]

    Colin asked 7 months ago

    The review examined all the relevant science relating to the management of the Lakes. The work being undertaken by the South Australian Government and the MDBA to identify adaptation strategies for the Coorong will explore opportunities for restoration and their potential social, economic and cultural benefits.  

  • I thought the aim of the RAMSAR aggrement was to protect the Hyper saline environment, that is allowing the lakes to go saline would not jeopodise the RAMSAR agreement? (this is just a matter of fact, not an apeal against the findings that we should not attempt to keep the lower lakes somewhat fresh)

    anonymous asked 7 months ago

    The Ramsar listing applies to the Coorong, Lower Lakes and Murray Mouth region not just to the Coorong.  More information on Ramsar sites in the Murray–Darling Basin.

  • What is the problem with the lakes being seasonally estaurine? the report equates a fresh water lakes system with a healthy CLLMM. But why wold an estaurine system be considered unnhealthy, when estaurine systems are also highlught ecologically productive. Why is a freshwa

    Claire M asked 7 months ago

    Upstream development has reduced the river inflow by about half, resulting in more frequent incursion of seawater into the Lower Lakes, and the barrages were built in 1940 in response to these changes, isolating the Coorong and the sea from the Lower Lakes. Removing the barrages would have a significant ecological and socio-economic impact. The review found that in the past 1 to 2 thousand years the Lower Lakes were largely fresh, with moderate tidal influence of seawater during periods of low river inflows. Without the barrages, the freshwater values in the Lower Lakes could not be maintained and it would significantly change the ecological character of this internationally important wetland, which Australia has an obligation to look after.  

  • The report does not appear to fully explore the counteracting force of the Southern Ocean in depositing sand into the Murray Mouth, which means no amount of extra freshwater flow nt the lakes will achieve the Basin Plan objectives on keeping the muth open and salinity targets in the lakes.will . The Wentworth Group contends no amount of extra freshwater flows into the lakes will keep the mouth open

    Claire M asked 7 months ago

    Over time, sea level rises will change the hydrodynamics of the Coorong and Murray Mouth, and increase seawater ingress into the Lower Lakes. There are two main challenges here. First, the barrier islands and the barrages will be overtopped more often. Second, the clogging of the Murray Mouth with sand transported by seawater, which is already happening, will be accelerated. However we need to appreciate that it will be some time before this happens, so we must start planning for this.  This may include engineering solutions. It may include identifying which ecosystems (and the services they provide) can be maintained, those that can transition to some new state, and those that cannot be sustained. It will be important to  know what is needed to help keep the system resilient to enable it to transition to a different future.

  • What consideration was given to the alterations with The South East Drainage system? Aquifer drainage?

    Daryl H asked 7 months ago

    The panel did not discuss the south east drainage scheme in detail, except stating that the South East Flow Restoration project would deliver about 6-47 GL/yr to the South Coorong near Salt Creek. The contribution of the scheme to the CLLMM region as a whole is minimal. The South East Drainage scheme puts water into the South Lagoon of the Coorong which is downstream and isolated from the Lower Lakes. There is limited information available on historical flows out of the SE into the Coorong as human activity has been influencing them since the 1860s. 

    The projected volumes entering the South Lagoon have relatively minor influence on the Coorong and have been incorporated into the Basin Plan through the sustainable diversion limit adjustment mechanism process. The drainage scheme helps reduce the demand placed on Murray River inflows in achieving salinity targets. The volumes derived from the SE are, however, relatively minor inputs to the system when compared to Murray River inflows. The project was funded collaboratively by the SA and Commonwealth Governments as part of implementation of the Basin Plan as part of efficiently achieving environmental objectives.  More information on the SE flow restoration project.

  • Are you able to present, in table form any key findings that a) align with, and b) vary from (if any) the baseline assumptions upon which the Basin Plan was formed. Would be good to have these results as a learning resource ie: hand out) for the Basin Communities Leadership Program.

    Emma B asked 7 months ago

    This question is out of scope for this review.  If you require further information please contact engagement@mdba.gov.au with specific requirements.

  • I was surprised to hear of the focus on the removal of the barrages. I hadnt heard of the debate about doing that and so my question is: what were the drivers for focussing the study on the barrages vis-a-vis other management strategy options that have been tossed around: Lock 0? Internal bunding of the lakes?

    Greg Co asked 7 months ago

    The review considered what the impacts of removing the barrages would be because many people had questioned the need for the Lakes to be maintained as freshwater systems. The concept of a lock zero has been previously examined and found not to be feasible and therefore not considered in this review.  

  • The report also mentions average wet years define this?

    Tanya asked 7 months ago

    This term was used generally to distinguish "wet" and/or "above average years" from "dry" and/or "below average years". The review did not specifically define what constitutes a "wet year".

  • I have read several papers about the science of the Lower Lakes and one in particular has raised some questions. Watching the tide roll away by Peter Gell set up a dispute between himself and Fluin et al. I am not a biologist (chemical engineer in fact) so I would appreciate some comment on this “dispute” because they seem at opposite end of the spectrum. David Thurley

    David T asked 7 months ago

    We believe that the debate you are referring to is the Peter Gell paper last year that suggests that the seminal study of Fluin et al. in 2007 was misrepresented in a subsequent 2009 Fluin et al. report and in the broader literature, which present the Lower Lakes as predominantly fresh before European settlement. The Panel's assessment is that Fluin et al. in 2009 did not misrepresent the conclusions of the original paper. The original paper in 2007 specifically said “the Holocene diatom assemblages of Lake Alexandrina reflect relatively freshwater conditions with longstanding and major inputs from River Murray, particularly after 2,000 years before present” and “marine water indicators were never dominant in Lake Alexandrina”. 

    The review found that in the past 1 to 2 thousand years the Lower Lakes were largely fresh, with moderate tidal influence of seawater during periods of low river inflows. Scientific debates like these are common, particularly with the considerable uncertainty—in the palaeoecological data,  in identifying the diatoms, in relating the different diatoms to salinity, and in dating the sediments particularly when the geomorphology and the hydrodynamics of the system have also been changing over the past 10,000 years.