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Selected Area: Lower Goulburn/Kaiela River

The Goulburn/Kaiela River is one of the hardest working rivers in the Murray-Darling Basin, providing water to support agriculture and rural communities, as well meeting growing downstream Murray River demands. At the same time, it is home to diverse flora and fauna. Our work is assessing how environmental and consumptive (irrigation) flows are affecting the ecosystem of the Lower Goulburn/Kaiela River, to help waterway managers to protect and enhance this vital water source into the future.

Image: Lower Goulburn River. Photo credit: Goulburn Broken CMA

We are honoured to work on the ancestral lands of the Yorta Yorta People and Taungurung People. We recognise their unique ability to care for Country and their deep spiritual connection to it. We honour Elders past and present whose knowledge and wisdom has ensured the continuation of culture and traditional practices. We are committed to genuinely partner, and meaningfully engage, with Traditional Owners and Aboriginal communities to support the protection of Country, the maintenance of spiritual and cultural practices and their broader aspirations in the 21st century and beyond.

About the Lower Goulburn/Kaiela River

The Lower Goulburn/Kaiela River stretches between the Goulburn Weir at Nagambie and the Murray River.  This river holds great significance for the Yorta Yorta people, featuring in dreaming stories as the Kaiela. The river is home to important native fish populations, along with turtles and platypus. The Lower Goulburn/Kaiela River floodplain is dominated by River red gum forests and woodlands, providing habitat for numerous bird and mammals.

The river has been heavily regulated for farming and flood prevention. Although it occupies just 2% of the Murray Darling Basin, the Goulburn Broken Catchment region provides 11% of the Basin’s stream flow. At the headwaters lies Lake Eildon. With a capacity of 3334 GL (3334 billion litres), Lake Eildon is the second-largest storage in the Murray-Darling Basin, only slightly smaller than Lake Dartmouth on the Mitta Mitta River. It is also almost seven times the capacity of Sydney Harbour (~500 GL). Lake Eildon stores runoff from the Victorian Alps primarily to support irrigated agriculture during the growing season (generally August to May). In the mid-reaches of the river, the Goulburn Weir regulates flow into the East Goulburn Main Channel and Warranga Channel, both of which supply the network of irrigation canals in the Goulburn, Campaspe and Loddon catchments. Below Goulburn Weir the river is not regulated, but levies and block banks have been built to reduce flooding of the Lower Goulburn/Kaiela River floodplain.

The regulation of flows provided by all this infrastructure has had significant impacts on the flora and fauna of the Lower Goulburn/Kaiela River. Like many parts of the Murray-Darling Basin, native fish numbers are at about 10-20% of pre-European settlement levels. Instream vegetation has all but disappeared. Bankside vegetation has come and gone with droughts and floods, and there is the sustained challenge of the delivery of irrigation trade water down the Goulburn/Kaiela River during summer. These flows are called Inter-Valley Transfers, and are resulting in un-seasonally high summer flows.

The Flow-MER Program in the Lower Goulburn/Kaiela River is conducting monitoring to understand how the environment of the river is responding to environmental and consumptive water flows. We are monitoring at 19 sites spread across the 220 km of the Lower Goulburn/Kaiela River. We then use that information in an adaptive management program to constantly improve the management of water in the river to try to strike a balance between human and environmental uses of water.

Location of Lower Goulburn monitoring sites. Source: Angus Webb

Our Approach

We are conducting monitoring throughout the year on all aspects of the environment, from physical habitat and ecosystem metabolism, through to ecological outcomes for macroinvertebrates (water bugs), vegetation and fish. We use the results of this monitoring to build predictive models that relate the amount of flow (or another property of flow, such as water velocity) to environmental responses. We can then use these models to predict what would happen under different flow conditions, for example, if there was less or more water for the environment available.

We are using the understanding gained through the use of modelled relationships, along with the expert knowledge of the scientists on the Lower Goulburn/Kaiela Flow-MER team to inform decision-making for water for the environment – when do we release, how much, and for how long?

We are communicating the outcomes of this work to stakeholders within the Goulburn catchment and beyond using print and social media, web-based content, and community engagement events. We also use these channels to learn more about the Lower Goulburn/Kailea River from those who have lived on it their entire lives.

Fish and water quality surveys underway on the Goulburn River. Photo credit: Arthur Rylah Institute
Waterbirds enjoying Yambuna Lagoon in the Lower Goulburn system. Photo credit: Murray Darling Wetland Working Group

Current activities

We monitor seven indicators in the Lower Goulburn/Kaiela River to track the outcomes achieved as a result of the delivery of Commonwealth environmental water.

Hydrology

We use the hydrological (stream flow) data collected for the Lower Goulburn River to analyse environmental responses to changing flows, and to run predictive models when flows are increased or decreased.

There are a number of stream flow gauges on the Lower Goulburn/Kaiela River and contributing tributaries, and these are maintained as part of the Victorian Government’s Surface Water Information System. We obtain the daily discharge and level data for these gauges, and infill where necessary, to build up a picture of flows for the year through the Lower Goulburn River. Additionally, we obtain the water accounts data to separate out the different ‘types’ of water that makes up the daily flow in the river: unregulated flows, irrigation water and Inter Valley Transfers, and environmental flows. With these data, we can relate observed ecological responses to flows in the river and then make predictions of what might have happened if (for example) no environmental flows had been delivered.

Hydrographs for the Murchison - Shepparton reach in Spring 2013. Photo credit: Goulburn Constraints Business Case Report - Jacobs Consulting

The Hydrology program is being led by Mr Ben Baker from Jacobs.

Hydraulic habitat

The hydraulic habitat of the river describes the forces exerted upon living things by the water running through the channel. It is often a useful way to think about how ecological responses are affected by flows.

While river flow in the Lower Goulburn/Kaiela River is expressed as volumes (ML/day), the living things in this environment experience properties of the flow such as depth, velocity and shear stress. We believe that these hydraulic variables may often be better predictors of environmental responses to changing flows than the flows themselves.

In the Long-Term Intervention Monitoring (LTIM) Project, we developed hydraulic models for four sites along the Lower Goulburn/Kaiela River. These allow us to calculate changes in hydraulic variables using the hydrology data from the river. We’ve used these models to calculate the duration of inundation for plants on the riverbank, the velocity of water during spawning season of Golden perch, and the peak height of flow events as a predictor of erosion or deposition of sediments on riverbanks.

Velocities in the Lower Goulburn River at the McCoys Bridge site demonstrate changes in velocity with flow changes, and this can be related to habitat conditions.
Velocity monitoring sites at McCoys Bridge. Image credit: Geoff Vietz

The Hydraulic habitat program is being led by Dr Geoff Vietz from Streamology.

Bank condition

The banks of the Lower Goulburn/Kaiela River support a range of plants that in turn form habitat for waterbugs and small bodied fish. At the beginning of the Long-Term Intervention Monitoring (LTIM) Project, there was community concern that environmental flows were causing an increase in riverbank erosion. We started monitoring erosion and deposition of sediments on the banks using erosion pins and were able to demonstrate that, while environmental flows did increase the amounts of both erosion and deposition, these increases were small relative to the normal processes of change in the river channel. Riverbanks are naturally dynamic environments and we expect them to change over time.

In more recent years, renewed concerns have arisen about the potential effects of summer Inter Valley Transfers (IVT). Early results show that the sustained high flows of IVTs during the warm, dry summer months, can have considerable impacts on erosion.

We have updated our methods from the original monitoring program and are now monitoring bank condition at three sites on the Lower Goulburn/Kaiela River using drone-based photogrammetry (taking high-resolution pictures of the banks and comparing them over time). This provides much richer data than was possible with the original erosion pin method, and has already demonstrated substantial erosion and deposition around major natural and regulated flow events.

Drone captured data before and after flows shows riverbank erosion and deposition caused by the often subtle changes in bank form, as emphasised by the major erosion seen on a more susceptible bank at Loch Garry on the Lower Goulburn/Kaiela River.

Results from drone-based photogrammetry showing bank change over time. Photo credit: Geoff Vietz
Riverbank erosion on the Lower Goulburn River. Photo credit: Geoff Vietz

The Bank condition program is being led by Dr Geoff Vietz from Streamology.

Ecosystem metabolism

Ecosystem metabolism refers to the production of food for fish and water bugs through photosynthesis (gross primary production) and the breakdown of that food to release the energy it contains (ecosystem respiration). These processes are the basis for the food web that links all animals and plants in the river system.

We measure ecosystem metabolism by monitoring dissolved oxygen levels in the river water at high frequency (a reading every 10 minutes). These data are then put through a statistical model to produce daily estimates of gross primary production and ecosystem respiration: increases in dissolved oxygen over time provides a measure of the rates of primary production and decreases in dissolved oxygen over time provides a measure of the rates of ecosystem respiration. We have four oxygen loggers deployed along the length of the Lower Goulburn River. These are being maintained by the consulting company ALS, as part of its monitoring work for the Victorian Government. We have used the data to explore how the rate and total amount of primary production and respiration changes with changing flows in the system.

Mean Daily Dissolved Oxygen Concentration for the four study sites 2018-19 in the Long Term Intervention Monitoring Project Goulburn River Selected Area. Source: Angus Webb et al, University of Melbourne

The Ecosystem metabolism program is being led by Assoc Prof Mike Grace from Monash University.

Macroinvertebrates (Water Bugs)

Macroinvertebrates are used as indicators of stream health across the world. In our program, a more important consideration is how macroinvertebrates can be a food source for the large-bodied fish that are the target of environmental flows. Any management actions that can increase the number of macroinvertebrates should be of benefit to fish populations.

We are measuring the abundance and biomass of large-bodied crustaceans (prawns and shrimps) that are the largest macroinvertebrate species in the Lower Goulburn River and are food items for fish like Murray cod, Golden perch and Trout cod. At eight sites spread along the river, we set bait traps regularly through the year to see how crustacean biomass changes along the river and with major flow events. We also take samples along the river’s edge to gain a basic picture of macroinvertebrate biodiversity using what are known as ‘rapid bioassessment’ methods.

A bait trap. Photo credit: D. MacMahon

The Macroinvertebrate program is being led by Prof Vin Pettigrove from RMIT University.

Bank vegetation

Vegetation on riverbanks helps to stabilise those banks and reduce erosion. It also provides habitat for aquatic animals when the river rises. During the Millennium drought, the semi-aquatic vegetation on the banks of the Lower Goulburn/Kaiela River was gradually replaced by terrestrial species during years of extreme low flows. When the drought broke in 2010, the high flows killed off much of this vegetation leaving the banks bare and susceptible to erosion. One of the focuses of environmental flows has been to improve the amount and diversity of riverbank vegetation.

In recent years, the advent of high summer Inter Valley Transfers (IVT) has posed a new threat to the recovering vegetation on the banks of the Lower Goulburn/Kaiela River. Sustained high flows during the warmer months of year is bad for young plants that germinate in spring.

Our monitoring is using surveys up and down the riverbanks at two sites on the Lower Goulburn/Kaiela River to track the abundance of key species over time and around major flow events. We are assessing vegetation in Spring, Summer and early Autumn to better understand how patterns of vegetation abundance over the growing season are shaped by environmental flows, natural flows and IVTs.

River bank at Loch Garry in March 2020 showing bare lower banks. Photo credit: Kay Morris
Erosion and exposed plant roots along the lower bank. Photo credit: Kay Morris

The Bank vegetation program is being led by Dr Kay Morris from the Arthur Rylah Institute for Environmental Research.

Fish spawning

The focus of this component is Golden perch and Silver perch. They are thought to be the only two fish species in the Murray Darling Basin that rely on increased discharge (flow) to initiate spawning. Golden perch and Silver perch spawn during rises in streamflow in spring-summer once water temperatures have reached certain thresholds. Monitoring conducted under the Long-Term Intervention Monitoring (LTIM) Project demonstrated that flow velocities (~30 cm/s average flow velocity) and temperature (~18.5 °C) make Golden perch spawning extremely likely.

We are monitoring spawning at four sites along the Lower Goulburn River using drift nets that are deployed overnight once a week for 10 weeks over spring and into early summer. In addition to eggs and larvae of Golden and Silver perch, we have detected breeding by native fish species including Murray cod, Trout cod and Murray River rainbowfish. These species spawn under a range of flow conditions. Demonstrating that they are spawning in the Goulburn River is important for understanding the health of the whole fish assemblage.

Golden perch larvae hatched from eggs collected during drift sampling. Photo credit: Wayne Koster

The Fish spawning program is being led by Dr Wayne Koster from the Arthur Rylah Institute for Environmental Research

Fish community

One of the principal aims of The Basin Plan is to improve native fish communities throughout the Murray-Darling Basin. Native fish have declined dramatically since European settlement of Australia with many different stressors, flow regulation among them, to blame. An improving native fish assemblage would demonstrate that environmental flows and other management actions are putting in place the environmental processes that can lead to long-term improvements in the top portions of the food web.

We are monitoring the fish community with an annual intensive survey that uses electrofishing and fyke nets to sample fish from ten sites along the Lower Goulburn/Kaiela River in Autumn. Collected fish are counted, measured and weighed before being released back into the river. This is a continuation of sampling that began under the Long Term Intervention Monitoring (LTIM) Project and is primarily aimed at providing data for basin-scale analyses of fish assemblage changes over time, and whether these can be related to environmental flows.

Murray cod being released post survey. Photo credit: Arthur Rylah Institute

The Fish community program is being led by Dr Wayne Koster from the Arthur Rylah Institute for Environmental Research

What we’ve learned

Over five years of monitoring in the Lower Goulburn/Kaiela River under the Long-Term Intervention Monitoring (LTIM) Project, we have learned that water for the environment has many benefits:

Environmental flows increase hydraulic diversity

Environmental flows can be used to increase the amount of specific hydraulic habitats available. For example, shallow slow flowing habitats over sandbars in the channel are important for promoting vegetation growth and providing invertebrate and fish habitat. These habitats are maximized at ~2000 ML/day. In contrast, we know that flows that cover the bed for macroinvertebrates, or create deeper pools for fish, are related to higher flows.

Image:  Native fish like a mix of hydraulic habitats.  Photo credit: EWKR Project

Vegetation growth increases as a result of flows

Bank condition monitoring has shown that deposition of new sediments occurs more in winter than in summer, partly driven by the proportion of flows in the river that are coming from the unregulated tributaries downstream of Goulburn Weir. This sediment helps to maintain and regenerate complex habitats in the channel and provides good conditions for the growth of new vegetation

Image: Growth of new vegetation post flooding.  Photo credit: EWKR project

Productivity increases and boosts food for fish

Environmental flows cause an immediate drop in the rate of ecosystem metabolism in the river, but this is more than made up for by the total amount of production and respiration that occur in the larger volumes of water. This increased amount of primary production creates more food resources for invertebrates and fish.

Image: Macquarie perch. Photo credit: Renae Ayres

Macroinvertebrates respond to flows

Following the natural floods of 2016 in the Lower Goulburn/Kaiela River, macroinvertebrate production increased considerably the following summer. This was particularly evident for the large-bodied prawns and shrimps that are important food sources for native fish. We believe this increase in production was due to the large amounts of organic matter (bark and leaves) that were washed into the channel by the floods and which provide a food source for invertebrates.

Image: Freshwater shrimp. Photo credit: Australian Museum

Riverbank vegetation is vulnerable to some flows

While environmental watering led to an increase in the overall cover of riverbank vegetation, the recent increases in Inter Valley Transfer (IVT) flows have impacted on vegetation on the lower regions of the bank. Increases in IVT delivery has increased the depth and duration of inundation of the lower part of the bank over the summer months. These flows have caused a reduction in occurrence of vegetation near the toe of the bank. Vegetation at the toe of the bank is important as it helps reduce erosion and channel widening. Managing the impact of IVTs is a major challenge for the future.

Image: Erosion and dislodgement of plants along the lower bank. Photo credit: Kay Morris

Flow cues trigger Golden perch spawning

We now understand the spawning cues for Golden perch extremely well and would be confident to initiate spawning every year if needed. However, what happens to the larvae produced, and how to attract juvenile fish from the Murray River into the Goulburn, remain as areas for further research and monitoring. Golden perch also seem to recruit at the scale of the entire southern Murray-Darling Basin, and this necessitates a more coordinated approach to flow management than has been the case to date.

Image: Young of year Golden perch. Photo credit: Brenton Zampatti

Fish communities are changing over time

The abundance of native fish has varied throughout years, with increases in some years offset by potential effects of a blackwater event that affected the Lower Goulburn/Kaiela River in January 2017. The annual surveys have detected several species of national importance, underlying the importance of maintaining and improving the Goulburn for native fish into the future.

Image: Trout cod detected during annual sampling. Photo credit: Wayne Koster

Latest updates

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Image caption: Lower Goulburn/Kaiela River in flood
Photo credit: Goulburn Broken CMA

Our team

Assoc Prof Angus Webb

Angus is an ecologist in the Water, Environment and Agriculture Program at the University of Melbourne. He has almost 20 years working in the rivers of the Murray-Darling Basin attempting to apply complex statistical methods to make better use of existing knowledge from experts, the literature and from environmental monitoring data sets, to better understand these environments.

Ms Xue Hou

Xue Hou is a research fellow in Environmental Flows at the University of Melbourne. She graduated with a Master of Engineering (Environmental) with Honours from the University of Melbourne in December 2018. She completed a project “The Effects of Environmental Flow Delivery in the Murray-Darling Basin on Gross Primary Production and Respiration in Streams”, based on the Long-Term Intervention Monitoring Project.

Dr Simon Treadwell

Simon is a Principal River and Wetland Ecologist at Jacobs. He has over twenty years of experience specialising in environmental flow and wetland water regime assessments and habitat rehabilitation. He provides advice to catchment management authorities and government agencies on waterway management across south eastern Australia.

Mr Ben Baker

Ben has twelve years of experience in hydrology and water resources modelling, providing data and modelling analysis for water authorities and CMAs. Ben has been involved in projects related to water resources and flood management for catchments across rural and urban Victoria.

Dr. Geoff Vietz

Geoff is a fluvial geomorphologist (water and sediments) and the Director of the consulting company Streamology Pty Ltd. Streamology is focused on ensuring good science informs the management of rivers for ecological and social benefit. In addition to consulting Geoff is a Senior Research Fellow at the University of Melbourne where he runs a waterway physical form program. He has more than 20 years’ experience working on rivers, including a large proportion of this focusing on the Goulburn River.

Assoc Prof Mike Grace

Mike is an Associate Professor in the School of Chemistry at Monash University, with teaching and research strengths in aquatic, analytical and environmental chemistry and in freshwater ecology (especially stream metabolism, carbon cycling and impacts of drugs).

Prof Vincent Pettigrove

Vin is the Chief Investigator for the Aquatic Environmental Stress (AQUEST) research group, RMIT University. He has over 30 years’ experience in the design and conduct of a broad range of biological and water quality research and monitoring programs that help catchment management authorities, water authorities and environmental regulators identify and address the priority issues impacting aquatic ecosystems. He has produced over 100 published journal articles and peer-reviewed conference papers.

Dr Kay Morris

Kay works at the Arthur Rylah Institute for Environmental Research (Department of Environment Land Water and Planning). She undertakes research on wetland and riparian vegetation to support evidence-based management and policy. Her research spans four broad areas: (i) understanding vegetation responses to threatening process including altered water regimes, salinization and nutrient enrichment, (ii) developing monitoring and evaluation programs to assess the effectiveness of management actions, (iii) understanding temporal and spatial patterns of plant dispersal by wind, water and waterbirds, (iv) modelling landscape patterns of biotic wetland connectivity.

Dr Wayne Koster

Wayne works at the Arthur Rylah Institute for Environmental Research (Department of Environment, Land, Water and Planning). Wayne has undertaken research extensively across Victoria, and more broadly in south-eastern Australia, including in the Goulburn River since 2003. The focus of much of Wayne’s recent work relates to the environmental water requirements of native fish and movements and migrations of freshwater fish species. Current projects include the Victorian Environmental Flows Monitoring and Assessment Program, diadromous fish migrations and links to flows using passive integrated transponder technology, and oceanic migrations of anguillid eels using satellite tracking. Wayne also regularly provides specialist advice to waterway managers on the environmental flow requirements for fish.

Simon Casanelia

Simon is the Environmental Water and Wetland Manager at the Goulburn Broken Catchment Management Authority. He has over 18 years of experience in natural resource management including environmental water planning, delivery and associated ecological monitoring.

Mr Daniel Lovell

Daniel has extensive experience developed over nearly 20 years managing water resources thorough in Northern Victoria. Daniel is employed at the Goulburn-Broken CMA as an environmental water co-ordinator has been involved in river and wetland management including the planning, delivery, monitoring and reporting of environmental water. As a result his experience Daniel has developed a strong understanding of the values, threats, hydrology, stakeholders, flow management and environmental water requirements of the streams of the Goulburn and Broken Catchment as well as water resource management tin the broader Murray Darling Basin.

Fiona Lloyd

Fiona is the the Communications Manager at the Goulburn Broken Catchment Management Authority. She has more than 20 years’ experience working as a journalist for regional and metropolitan daily newspapers and in communications for the private sector and local and state governments.

Kerry Webber

Kerry is the Goulburn MER Project Manager at the Commonwealth Environmental Water Office. She has around 35 years’ experience developing policy and coordinating major programs across multiple disciplines including in health, education and the environment. Her focus has been on the communications and engagement aspects of the work, and in particular interacting with stakeholders to ensure that products and messages are suitable for their professions and useable by community interest groups.

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This page contains information specific to the Victorian Rivers Commonwealth Environmental Water Office (CEWO) Monitoring, Evaluation and Research Project. For further information about water use in the Victorian Rivers, please click here to visit the CEWO website.

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