Flow on effects – new tools to support the integrated management of river flows and floodplain infrastructure along the River Murray

Infrastructure has been built along the River Murray over the last ten years to help sustain critical floodplain ecological communities by recreating some of the natural inundation regime that would have occurred prior to development. The benefits of providing these floodplains events are relatively well known, but until recently it wasn’t clear what effects infrastructure was having on the ecology and water quality in the river itself.

We’ve done a lot of field work to try and understand what happens when we operate the river’s infrastructure. Now we can use the results to assess future operations so we don’t compromise some of the river’s ecological processes by trying to look after the floodplains,” said Dr Matt Gibbs.

Dr Matt Gibbs (The University of Adelaide and Department for Environment and Water [DEW]) has led a two-year project with Professor Justin Brookes (The University of Adelaide) and colleagues at CSIRO, SARDI, DEW and The University of Adelaide. The team quantified the relationships between the hydraulics of the river, water quality parameters and ecological responses. A report detailing their research findings has just been released.

If we’re pushing water out on floodplains at lower flows, that means we’re making the river flow even slower and potentially affecting ecological processes,” said Dr Gibbs.

Some phytoplankton, particularly the highly digestible food sources for many grazers, needs turbulence and higher water velocities to remain in suspension. Under low flows, rivers can stratify, increasing the risk of cyanobacterial growth, or algal blooms, that thrive in stiller water. Dr Gibbs and his team used current and historical data to develop a model that could assess the likelihood of blooms under different river management scenarios.

The team also sampled organic matter on the floodplains to determine how fast it accumulates and decays so they could predict how it might impact water quality under different flood and inundation scenarios. High levels of microbial carbon degradation in the river can lead to low dissolved oxygen levels and hypoxic blackwater events. Their resulting dissolved oxygen/dissolved organic carbon model is already helping water managers in South Australia and beyond, with CSIRO adopting and using the research upstream for the Murray Darling Basin Authority.

Leaf litter traps along the river (Photo: Todd Wallace)

Dr Gibbs and his research team also investigated the relationships between river hydrodynamics and the transport of seeds, microinvertebrates and Murray cod larvae – all important aspects of the river’s ecology and food web.

We found that Murray cod larvae prefer to be somewhere that’s not flowing too quickly, where they can live, but they need the faster water flowing past. That will bring the food past so they grab something to eat and move back again. Working at this scale in the river, as well as the whole of reach scale is quite hard to do, but we’ve identified some relationships that allow us to capture the important dynamics within our models,” Dr Gibbs said.                                                                                                                                                                      

                       Microcrustacean (Photo: Deb Furst) and codling (Photo: Chris Bice)

It’s the first time a model has been developed for the River Murray that incorporates water quality characteristics, ecological responses, and river hydraulics at the scale of hundreds of kilometres to inform infrastructure operations. The new models and research have been incorporated into the eWater Source hydrological model of the South Australian River Murray, so water managers can better predict what will happen when the hydraulics of the river change with regulator operations.

Our hydrology team in DEW is using these results right now. At this time of year, we’re doing a lot of planning for what we’ll do in winter and spring when we want to get some of these ecological responses, like inundating vegetation or providing fish habitat in certain areas. We’ve only got so much water and we’re trying to look after as many components of the ecosystem as we can,” said Dr Gibbs.

As well as looking at different ecological processes in detail, the team also looked at the River Murray’s food web, to see how energy sources tracked up through the food chain.

“We’re bringing these carbon and nutrients into the river, off the floodplain and we assume that’s a good thing and it’s going into plankton, to invertebrates, to little fish and to big fish. But that’s an assumption, we haven’t really tested it. So that was the idea of using isotopes to track how those energy sources flow up the food web.

The team sampled over two years – one (2017) where the river was allowed to flow without using any of the structures and the other (2018) where the water level was raised using a regulator – expecting that the latter would give rise to more resources, and a more diverse food web. In fact, they found the opposite and think this might be due to the large floods in 2016 having such a positive impact on the food web that carried over into 2017.

That’s the next direction, trying to understand these processes and how by using these structures and inundating floodplains, we can really kick off the productivity of the whole river,” said Dr Gibbs.

Contact Dr Matt Gibbs for more information about the eWater Source model and the Ecological connectivity of the River Murray project or get in touch with Goyder Institute Director Dr Kane Aldridge for more information about the Institute’s research within the Murray Darling Basin.

The report referred to in this article is Ecological connectivity of the River Murray: Managing ecological outcomes and water quality risks through integrated river management (2020) which covers the research from a very large collaborative team including:
• Chris Bice (propagule transport) and Jason Nicol (propagule transport) – SARDI
• Deborah Furst (propagule transport), Justin Brookes (phytoplankton), Maria Marklund (phytoplankton), Todd Wallace (dissolved oxygen, food webs) and Matt Gibbs (dissolved oxygen, model integration) – University of Adelaide
• Nina Welti (food webs), Heidi Pethybridge (food webs), Lei Gao (phytoplankton, model integration), Klaus Joehnk (phytoplankton) and Brenton Zampatti (propagule transport) – CSIRO.

Tags: Department for Environment and Water (DEW) Goyder Institute News Modelling Murray River Murray-Darling Basin

Other News

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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

Accountant

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.