Policy changes are needed to better protect environmental water from climate change in the Murray-Darling Basin

With discussions regarding environmental water recovery in the Murray-Darling Basin Plan receiving attention lately, we invited Prof Barry Hart to write an article on the topic, building on his extensive experience in water research and management.

Did you know that in the Murray-Darling Basin (MDB) climate change will impact the volume of water for the environment significantly more than the volume for consumptive uses such as irrigation? That is unless we change the current policy settings or allow for these effects in the way we plan for a changing climate.

What is the situation?

The fact that environmental water is being adversely impacted by climate change has been known for over a decade. In 2009, CSIRO reported that by 2030, assuming a median climate change scenario, the available surface water volume in the Murray-Darling Basin would be reduced by 12 percent or almost 2,500 GL/year. Further, CSIRO showed that the impact on the sharing of this water between consumptive use, losses and outflows would be significant and not equal. They predicted that consumptive uses would be reduced by only 4 percent, while water to maintain river and floodplain ecosystems (environmental water = ‘losses’ and outflows) would be reduced by 12 to 24 percent.

More recently, in assessing the impact of lower inflows on state shares under the Murray–Darling Basin Agreement, the Interim Inspector-General of Murray–Darling Basin Water Resources showed that the inflows to the River Murray have fallen by around 39% since 2000 compared with the mean flow in the period 1985 to 2000. But the impact of these overall reductions in volumes is not equally distributed between water for the environment and that for irrigation and other consumptive uses; currently the environment is being hit the hardest.

These unequal impacts on environmental water are not only occurring in the Murray-Darling Basin. A recent assessment of the water resource for Southern Victoria found that surface water resources had declined in most rivers with those closer to Melbourne (e.g., Yarra, Maribyrnong, Werribee and Moorabool) declining by 15-25% over the past 15 years. Again, these overall declines were not shared equally between the environment and consumptive uses – environmental volumes declined by 4 to 28 percent compared with 1 to 13 percent for consumptive uses.

In summary, assuming similar climate change impact as used by CSIRO (2009), the below graph shows the likely changes to entitlement and non-entitlement water in the MDB by 2050 compared with the current situation, with environmental water reduced by over four times that of entitlement water.

Figure 1: The likely impacts of climate change on entitlement and non-entitlement water in the MDB by 2050 compared with the current situation. Assumes climate change impact are the same as in CSIRO (2009); average total inflow volume 32,553 GL/year minus 2,733 GL/year due to interceptions (see Basin Plan (2012), Table 1, Schedule 1).

So why is this situation occurring in the MDB?

In simple terms, water in the MDB can be divided into two categories – entitlement water and non-entitlement water – which are protected by law very differently.

Entitlement water – is able to be harvested and held in storages, with entitlement holders able to ‘call upon’ their entitlement and have the water delivered to a farm or reach of river. These entitlements can be either high and low reliability depending upon the type of entitlement, they are well protected by law and can be bought and sold on the water trading market. Until around 2009, nearly all entitlement water was used for irrigation.

Now, because the amount of water allocated for consumptive use was excessive, some of these entitlements (approximately 20 percent) have been acquired by the Commonwealth Government for the environment. This ‘held’ environmental water is protected in the same way as consumptive water entitlements and has been essential for protecting critical ecosystems during dry times.

Non-entitlement water is sometimes called ‘planned’ or ‘above cap’ water because its management is controlled through the state regional water resource plans. This environmental water is essential for filling wetlands and triggering the mass breeding events that help fish and bird populations to recover after dry times. However, it is not legally protected in the same way as water entitlements or water rights, and can be difficult to define and monitor. For these reasons, this non-entitlement environmental water is currently more at risk from climate change than entitlement water.

This is very important, since approximately 58 percent (or around 19,000 GL/year) of the total water resource in the MDB is non-entitlement or environmental water (total input volume 32,553 GL/year; average use under entitlements of around 10,890 GL/year [of which around 2,100 GL/year is held environmental water]).

To ensure there is not a disproportionate impact of climate change on environmental water, the current policy settings in the Water Act (2007) and the Murray-Darling Basin Plan (2012) need to change. The currently scheduled review of the Water Act in 2024 and the Basin Plan by 2026 is the obvious time for this to occur, but there is some urgency as this is just two to four years away.

What are some options for change?

There are a number of options for ensuring this imbalance between water for the environment and irrigators does not continue no matter what climate change brings. Some possibilities are discussed below, all of which will be highly contested.

Option 1: Keep the existing ratio of entitlement water to non-entitlement (environmental) water constant – currently consumptive water use or sustainable diversion limit (SDL) is around 27% of the total surface water resource or around 8,800 GL/year compared to the total of ca. 32,600 GL/year. The implication of this change in policy would be that both the environment and the consumptive users would suffer the same proportional reduction in water availability with climate change, or one could argue they both suffer the same ‘pain’. This could be achieved through a combination of amendments to: water resource plans; bulk entitlements; annual allocation strategies; or dam operational plans, to make them more adaptable to a variable and changing climate.

Option 2: Develop a new sustainable diversion limit (SDL) that accounts for climate change – this would involve very difficult decisions for the community to make regarding: what water-dependent environment was desired and achievable in the future (the Ecologically Sustainable Level of Take); and what type and extent of the irrigation industry was desired and achievable in the future. In essence, this would mean redoing a major component of the Basin Plan with an eye on the future (20 to 50 years hence) reduced water resources due to climate change.

Option 3: Develop a new sustainable diversion limit (SDL) that allows for the differing effects of climate change on entitlement and non-entitlement water – following key elements of the approach under Option 2 to determine the balance between environmental and economic outcomes under plausible future climates, the SDL could be set in a way that allows for the differing effects of climate change on entitlement and non-entitlement water. This approach could achieve the overall outcome sought with substantially less issues in term of impacts on property rights.

Another option proposed by the Wentworth Group is the ‘downstream flow targets’ option. These targets would equate to existing state or Basin Plan environmental water requirements (EWR) and would have to be met before lower security water entitlement holders could commence extractions.

All these options have challenges, and there may be other options available to address preferences for changing the current set of rules. But protecting the environment of the Murray–Darling Basin against climate change is an important responsibility for the Commonwealth and State governments, and it must be done hand-in-hand with the community. Working through these options will be an important part of the 4-year journey to the Basin Plan Review in 2026.

How to decide on an equitable climate ready policy?

The history of changes to the distribution of the Basin’s water resources between consumptive and environmental uses has been divisive – a ‘them and us’ situation has occurred. The decision-making processes adopted for the development of the initial 2012 Basin Plan led to considerable unrest, particularly in rural communities where it was felt that their economy was going to be severely impacted.

It is obvious that the next Basin Plan must be developed more collaboratively. Subject to meeting Water Act requirements, including the need to act on the basis of the best available science, there is potential to use deliberative decision-making processes and involve independent groups, such as Watertrust Australia, when developing the next Basin Plan.

Finding the right balance between the environmental, social, economic and cultural outcomes to be achieved in the Basin is a job that must be done collectively. All people who value the Basin must be heard, and those making the final decisions must do so transparently and be accountable for the decisions.

Tags: Climate Resilience Goyder Institute News Murray-Darling Basin Water for Agriculture Water for Cities and People Water for Industry Water for Mining Water for the Environment

Other News

We are delighted to welcome Fiona Adamson and Dr Hamideh Nouri to the Goyder Institute for Water Research team.  Fiona has joined us on secondment from Institute partner Flinders University, where she has been providing administrative and
The Millennium Drought (1996-2010) had a devastating environmental, economic, social and cultural impact throughout the Murray-Darling Basin. The Coorong, Lower Lakes and Murray Mouth (CLLMM) region, situated at the end of the Basin, was no exception.

Photo Gallery

Chris Wright

Manager Water Science, DEW

Chris Wright holds significant experience in public sector senior leadership, having led policy, scientific and operational business units over the last twelve years in both State and Commonwealth government agencies. Chris has excellent experiences in leading policy and strategy formulation. He is skilled in building and maintaining networks across the public and private sectors to facilitate business delivery; leading and negotiating with others to achieve outcomes; and in bridging the science-policy gap, drawing on earlier roles in geospatial information systems (GIS) consulting. Chris’s formal qualifications include a Bachelor of Social Science, a Masters of Spatial Information Science and graduation from the AICD Company Directors course in 2019.

Dr Ilka Wallis

Senior Lecturer, Flinders University

Dr Ilka Wallis is a hydrogeologist with areas of expertise in quantitative hydrogeology and geochemistry. Ilka focuses on the development of reactive geochemical transport models which integrate fundamental processes that are normally studied in isolation (hydrogeological, mineralogical, geochemical and biochemical).

Ilka is also an Adjunct Professor, Department of Civil Engineering, University of Manitoba, Canada since 2017.

Peter Goonan

Environmental Science Branch, EPA

Peter Goonan is the Principal Aquatic Biologist in the Environmental Science Branch of the EPA. He has over 30 years’ experience monitoring the condition of aquatic ecosystems in SA and assessing the environmental effects caused by discharges, deposits and contaminants entering inland and coastal waters. He specialises in aquatic invertebrate identification and their responses to contaminants and water quality stressors. He also provides expert professional advice relating to water quality risks, regulation, policy, and strategic directions, and represents the EPA as an expert witness in court.

Dr Paul Monis

Manager, Research Stakeholders and Planning, SA Water

Dr Paul Monis is a technical expert within SA Water’s Business Services group, which provides scientific expertise to support the delivery of water and wastewater services to SA Water’s customers. He has specialist expertise in the areas of biotechnology and microbiology, with almost 20 years’ experience applying DNA-based and other technologies to address water quality challenges posed by microorganisms, especially enteric pathogens. Dr Monis also holds title of Adjunct Associate Professor at Flinders University, the University of Adelaide and UniSA.

Jennie Fluin

Principal Advisor Research Partnerships, DEW

Jennie’s role in the Department for Environment and Water (DEW) allows her to foster and strengthen opportunities for researchers to better connect with government to enable evidence-based decision making. Jennie has extensive experience working in both universities and government, allowing her to bridge the divide between the two sectors. She is focused on connecting natural resource researchers with natural resource decision makers, and facilitating fit for purpose partnerships.

Dr Tanya Doody

Principal Research Scientist, CSIRO

Dr Tanya Doody is a Principal Research Scientist working on high impact spatial eco-hydrological projects within CSIRO’s Land and Water Business Unit. Dr Doody leads the Managing Water Ecosystems Group, based in Adelaide, Albury and Canberra and has significant experience in quantifying the water requirements of vegetation and at times, their impact on water resources. This involves ecophysiological field-based research to underpin remote sensing tools to scale regionally to improve our understanding of the effect of flood regimes on the health of water-dependent ecosystems on the Murray-Darling Basin floodplains. Additional research includes investigating the ecological response of vegetation to water availability and environmental water to inform integrated basin water planning and management.

Professor Lin Crase

Dean of Programs (Accounting & Finance), UniSA

Professor Lin Crase is Professor of Economics and Dean of Programs (Accounting & Finance) at UniSA. He joined UniSA in February 2016 as Head of School of Commerce. Prior to commencing at UniSA, Lin was Professor and Director of the Centre for Water Policy and Management at La Trobe University.

Lin’s research has focused on applied economics in the context of water. He has analysed water markets and the property rights that attend them, water pricing and numerous applications of water policy. Whilst his expertise includes the Murray-Darling Basin in Australia, he has also worked on projects in south Asia, Japan and Europe. Lin has published over 100 journal articles, numerous book chapters, four books and a range of other papers and opinion pieces.

Professor Justin Brookes

Director, Water Research Centre, University of Adelaide

Justin has broad research interests in limnology and water treatment with a primary focus on coupling between hydrodynamics, biology and water quality contaminants such as cyanobacteria and pathogens. He is a founding member of the management committee of the IWA Specialist Group on Lake and Reservoir Management and member of the Steering Committee for the Global Lakes Ecological Observatory Network.

Justin has a PhD and a Bachelor of Science degree with Honours from the University of Adelaide.

Daniel Flaherty


Daniel Flaherty is the Accountant for the Goyder Institute for Water Research.

Daniel has extensive experience in higher education having worked in senior financial management roles at the University of South Australia, Flinders University and the University of Adelaide over the past 26 years. Daniel has also been a Board Director on a number of university related entities. Prior to that, Daniel has worked in a range of agencies in the Commonwealth and State Governments.

Daniel is a Fellow of CPA Australia and has a Bachelor of Economics from the University of Adelaide.

Dr Alec Rolston

Interim Director

Alec Rolston joined the Institute in 2021 as Research Program Manager of the Goyder Institute’s research projects in the Healthy Coorong, Healthy Basin program. He has extensive experience in integrated water resource management, integrated catchment management, drinking water source protection and wetland ecology, conservation and management across Europe and Australia.

Alec holds a PhD from the National University of Ireland Maynooth and has worked with An Fóram Uisce|The Water Forum and the Dundalk Institute of Technology in Ireland as well as the MANTEL Innovative Training Network across Europe.

Alec spent his early career in Adelaide working with Flinders University through the Coorong, Lower Lakes and Murray Mouth (CLLAMM) Ecology Research Cluster and within the Department for Environment and Water.

Daniel Pierce

Research and Development Officer

Daniel Pierce has managed research projects at the Goyder Institute for Water Research since November 2017 under both the second and third terms of the Institute.

Daniel brings experience in project management and knowledge transfer and application from 4 years working as a Senior Hydrogeologist in the Department for Environment and Water (DEW) in South Australia and from 13 years of private sector work in environmental management, science and engineering in Australia and the South Pacific. His work with DEW has included providing technical advice to the development and revision of Water Allocation Plans around South Australia in collaboration with researchers and policy makers, and managing a team of groundwater modellers and hydrogeologists involved in an assortment of water resource management issues.

Daniel has a Bachelor of Engineering (Hons, Environmental) and a Bachelor of Science (Geography) from the University of Western Australia.

Professor Enzo Lombi

Dean of Research, UniSA STEM

Professor Lombi’s main contributions to environmental research cover various aspects of contaminant risk assessment, biogeochemistry, ecotoxicology and waste management. Furthermore, the methodological development he has pursued in his research has provided the basis for collaborative efforts in a variety of research areas ranging from soil fertility and plant physiology to human health issues related to contaminant uptake via occupational exposure and diet. In the last few years he has been increasingly focusing on the transformation and toxicity of manufactured nanomaterials in the environment.

Dr Carmel Pollino

Research Director Land and Water, CSIRO

Dr Carmel Pollino is a Research Director for Land and Water at CSIRO. She has 20 years of experience working on water issues in Australia and throughout Asia. Carmel has degrees in science and environmental law and works across the science and policy interface. Significant areas of research in Environmental Flows, Hydrology, Ecology and Integrated River Basin Planning. Carmel is the lead and also a contributor to global working groups on water and has published widely in this domain.

Professor Bronwyn Gillanders

Head of School of Biological Sciences, The University of Adelaide

Professor Bronwyn Gillanders is interim Head of School of Biological Sciences at the University of Adelaide. Prof Gillanders completed her BSc at the University of Canterbury, MSc at the University of Otago and her PhD at the University of Sydney. She has a research background in environmental science focused predominantly on freshwater and marine ecology.

Her research interests include integrated marine management; coastal carbon opportunities; multiple use activities and cumulative impact assessment; biology, ecology and fisheries of cephalopods; stocking and provenance of fish; plastics in the marine environment including in seafood; use of fish bones (and other calcified structures) for assessing ecological and environmental change. She has trained and mentored ~70 Honours and Higher Degree Research students and shaped the future of 1000s of students through her undergraduate teaching. She is passionate about encouraging capable women to enter and remain in science careers.

Dan Jordan

Director, Water Security, Policy and Planning, Department for Environment and Water (DEW)

Dan Jordan is the Director, Water Security, Policy and Planning, Department for Environment and Water (DEW). Dan is also the Basin Officials Committee Alternate Member for South Australia.

Professor Okke Batelaan

Dean, School of the Environment, Flinders University

Professor Okke Batelaan is a graduate of the Free University of Amsterdam, Netherlands (MSc – Hydrogeology) and of the Free University Brussels, Belgium (PhD – Engineering). He worked for more than 20 years at the Free University Brussels and also led the hydrogeology group at the KU Leuven, Belgium since 2006. He was chairman of the Interuniversity Programme in Water Resources Engineering.

Since 2012 Okke Batelaan is Strategic Professor in Hydrogeology and currently Dean of the School of the Environment, Flinders University. Okke has broad experience in teaching groundwater hydrology, groundwater modelling, GIS and remote sensing for hydrological applications. He was supervisor of more than 140 MSc and 25 PhD students. He has extensive research experience and a publication record in shallow groundwater hydrology and modeling, recharge-discharge estimation and modeling, urban hydrology and distributed modelling, ecohydrology and impacts of land use and climate change on groundwater systems. He coordinated and participated in a large number of projects in Europe, Africa, South America, Asia and Australia. He is editor-in-chief of Journal of Hydrology: Regional Studies and of MDPI-Hydrology.