Selected Area: Gwydir

The Gwydir is a special place with significant environmental, cultural and economic values.  Our work here focuses on monitoring and evaluating the outcomes water for the environment enables in some of the largest waterbird breeding colonies in Australia.  We also work in the rivers and floodplains to assess water quality, fish breeding and food webs.

Nankeen night herons, NSW.  Photo credit: Gwydir Research Team

We acknowledge and respect the Traditional Owners as the First Peoples of the lands and waters of the Murray Darling Basin. 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.

Artwork credit: Wiradjuri Artist Rebecca Salcole

About Gwydir

The Gwydir catchment is part of the Murray-Darling Basin and covers an area of 26,600 square kilometres. The Gwydir River begins near Uralla on the New England Tablelands and flows north-west towards Moree. Downstream of Moree the Gwydir River divides into the Mehi River and the lower-Gwydir Wetlands which is comprised of the Gingham Watercourse and the Lower Gwydir River. Copeton Dam is the major reservoir in the Gwydir catchment.

Figure 1 shows the Selected Area within the Gwydir catchment.

The Gwydir Wetlands are situated along the lower Gwydir and Gingham watercourses, approximately 60km west of Moree in north-west NSW. A number of wetlands within the system are listed under the Ramsar convention as ‘Wetlands of International Importance’.

Figure 2: Gwydir Wetlands: Gingham and Lower Gwydir Watercourses.

Our Flow-MER work will allow us to make more informed decisions about the management of water for the environment. This will enable us to maintain and improve habitat quality and river connectivity within the Gwydir Catchment. The Gwydir contains a number of ecologically important assets including waterbirds, bird habitat, wetland vegetation and species, and ecological communities of special significance.

Bird species in the Gwydir

Some of the largest waterbird breeding colonies in Australia are supported by the Gwydir Wetlands, with 75 different species recorded. The wetlands also provide refuge during dry times. The images below show some of the bird species found in the Gwydir Wetlands listed as vulnerable or endangered.

Australian painted snipe (Status: Vulnerable). Photo credit: Wikipedia
Brolga (Status: Vulnerable). Photo credit: Wikipedia
Black falcon (Status: Vulnerable). Photo credit:
Freckled duck (Status: Vulnerable). Photo credit: Wikimedia Commons
White-bellied sea eagle (Status: Vulnerable). Photo credit: Wikimedia Commons
Black-necked stork (Status: Endangered). Photo credit: Wikimedia Commons
Magpie goose (Status: Vulnerable). Photo credit: Wikimedia Commons
Little eagle (Status: Vulnerable). Photo credit: Wikimedia Commons
Australian bittern (Status: Endangered). Photo credit:
Spotted harrier (Status: Vulnerable). Photo credit: Flickr, Julian Robinson

The challenges we are facing

As a result of extensive clearing for agricultural development, vegetation communities on the floodplains in the Gwydir are highly fragmented (broken up) and in poor condition. Since the regulation of the Gwydir River in the 1970’s (construction of Copeton Dam and management of water), the extent and condition of semi-permanent wetland and floodplain vegetation communities have declined. Less frequent inundation of the floodplain as a result of regulation has reduced floodplain pasture productivity and influenced changes in land use from grazing to cropping.

These changes means that the Gwydir now has a number of Endangered Ecological Communities and Threatened Ecological Communities.  This has a flow on effect as vegetation provides habitat for waterbirds, reptiles, frogs, woodland birds and terrestrial species such as the Eastern Grey Kangaroo. Floodplain wetlands and waterholes, in-channel lagoons, sedgelands, cumbungi stands, lignum, belah, coolabah and river red gums are key vegetation communities that make up key waterbird breeding habitat.

Aquatic ecological communities are also in poor condition, with a decline in native fish populations and species such as the Murray cod, Golden perch, Silver perch, Purple spotted-gudgeon and Eel-tailed catfish, of concern. Threatening processes to aquatic ecological communities in the Gwydir Wetlands include:

  • installation and operation of in-stream structures that change natural flow patterns of rivers and streams (dams and weirs)
  • the removal of large woody habitat which provides in-stream habitat for fish and invertebrates
  • the degradation of native riparian vegetation (vegetation that borders waterbodies) due to clearing, grazing, spray drift and changes in flow patterns
  • the introduction of native and introduced (Carp, Goldfish and Gambusia) freshwater fish to new areas of the river catchment which is outside their natural range. This creates more competition for resources and increases predation of other native fish species


Different native fish species have different cues that stimulate breeding events, though spring and early summer is typically when they occur. Breeding events may be triggered by increased flow (more water in the system) or higher water temperatures.

River connectivity (where flow in the river is continuous and not broken up creating isolated pools) is important for the movement of fish up and down the catchment, particularly during breeding seasons. Enabling fish to move is crucial, as many species use floodplains, creeks, streams, in-stream lagoons and waterholes for feeding and reproduction. They also seek deeper pools as refuge during dry times when flow may cease in the river for an extended period of time. Connectivity also allows for genetic diversity among fish populations and for the colonisation or recolonisation of unoccupied areas.

Complex ecosystems:

The Flow-MER Program aims to identify and record how water for the environment effects these complex ecosystems within the Gwydir. Understanding how they are affected will allow us to make more informed decisions about when and how much water for the environment should be released to improve habitat conditions. Improving habitat conditions for waterbirds, native vegetation, native fish and other aquatic and terrestrial species will aid in ensuring their presence within the Gwydir Catchment continues.

Tyreelaroi reguator looking downstream. Photo credit: Darren Ryder

Our approach

The Flow-MER program is designed to assess how water for the environment effects ecosystem interactions within the Gwydir Selected Area. This involves monitoring and evaluating the response of key indicators including waterbirds, fish, water quality and movement, invertebrates (food webs) and vegetation to the presence and absence of water in the system.

The Flow-MER Program is a three year continuation of the Long-Term Intervention Monitoring (LTIM) project which took place 2014-2019. It will allow our team to continue to work identifying and recording how environmental water effects ecosystems within the Warrego-Darling.  We will also be extending our communication and research components.

Wetland vegetation monitoring site. Photo credit: Gwydir Research Team
Water quality testing. Photo credit: Iris Tsoi

Current activities

Our current activities are focused on monitoring and reporting the outcomes of environmental watering against a set of core indicators within the Gwydir River selected area.

Hydrological analysis

We analyse river flow, using up to 15 gauges to understand how much water is coming and where it is going. We map the extent of wetland inundation using satellite image analysis. Our focus is on environmental water, when it is delivered and how far it moves.

Flow hydrograph. Source: Research Gate

Food webs

Our team sample the rivers and wetlands regularly to understand changes in water chemistry with different flow types. We also survey for micro-invertebrates and macro-invertebrates to understand how changes in water lead to a productive food web. When water for the environment comes, we want to know how the water quality changes and the food webs it can support.

Ben Vincent conducting invertebrate sampling. Photo credit: Sarah Mika


We survey vegetation at fixed plots across wetlands and are into our sixth year of monitoring these sites.  We have seen dramatic changes, from almost bare soil, to fire, to luxuriant dense wetland vegetation. Overall our monitoring work is showing that vegetation is responding positively to water for the environment.

Vegetation monitoring transect. Photo credit: Gwyidr Research Team


Fish have been surveyed in multiple channels and wetlands within the lower Gwydir. We have found good fish diversity but generally low numbers. The movement of Murray cod and Freshwater catfish up and down river channels is often sparked by changes in flows.

Releasing a Murray cod during a fish survey. Photo credit: Gwydir Research Team


If you water it, they will come. Over six years of surveys we have found that waterbirds will quickly arrive when the floodplains are watered.  Waterbirds respond rapidly to environmental watering and we have recorded positive feeding, breeding and recruiting outcomes.

Shore waterbirds in the shallow water they need for foraging. Photo credit: Gwydir Research Team

What we’ve learned

Wetland inundation

In 2014/15 the greatest inundation of wetlands occurred, and this was due to the delivery of water for the environment. Environmental flows inundated (flooded) plant communities and led to greater diversity and richness of species. Inundation also helped to control the weed species Lippia, and encouraged the growth of native wetland species like Water couch.

Image caption: Bunnor. Photo credit: Gwydir Research Team

Better habitat for waterbirds

With plant communities benefiting from environmental flows, habitat to support foraging, breeding and survival of a diverse range of waterbirds was also created.  This enabled successful bird breeding events in many of the Gwydir wetlands we monitor.

Image caption: Plumed whisterling duck. Photo credit: Gwydir Research Team

Native fish need more support

Native fish populations responded positively to water for the environment, with flows creating opportunities for breeding and foraging throughout the system. These flows also improved water quality.  Our findings did, however, highlight that native fish populations are under stress, and that species such as Silver perch, Freshwater catfish, Golden perch and Olive perchlet are in very low numbers, with few or none captured over the 5-year monitoring project.

Image caption: Adult catfish. Photo credit: Gwydir Research Team
Gingham waterhole turtles. Photo credit: Darren Ryder
Brolgas at Little Lagoon. Photo credit: Gwydir Research Team

Our team

Dr Paul Frazier

I am one of the Project Directors for the MER Program. I also organise and implement the communication strategies for the MER Program in the Gwydir Selected Area. My role involves liaising with all stakeholders and analysing, writing up and communicating our findings with CEWH through our annual reports.

Dr Mark Southwell

I am one of the Project Managers for the Gwydir Selected Area. I organise and undertake field trips, liaise with stakeholders in both areas and carry out technical work associated with hydrology and vegetation indicators. My role also includes writing up the project findings in our annual reports.

Dr Sarah Mika

I am one of the Project and Research Managers for the Gwydir Selected Area. I sample and analyse the water quality, microinvertebrate and macroinvertebrate indicators. I am also responsible for the overall reporting of project findings.

Dr Gavin Butler

Gavin is the fisheries leader, and oversees and directs the fish sampling, analysis and reporting for the project. He even gets his feet wet sampling from time to time.

Dr Deborah Bower

I work for the University of New England and I am responsible for research and monitoring of biodiversity including frogs and turtles. This involves organising and undertaking field work, liaising with landholders and recording our findings so they can be written up in our annual reports for the Program.

Ben Vincent

I’m the vegetation ecologist for the Aquatic Ecology and Restoration Research Group at the University of New England. My role in Flow-MER is to continue to build upon the good ecological work done before me. I collect data on the different wetland and floodplain plant species that come and go as a result of water availability.

Dr Ivor Growns

I am responsible for sample processing, data collation and reporting our findings for invertebrates. I coordinate the upload of all indicator data to the Monitoring Data Management System for the CEWH. I am also passionate about communicating our findings to the broader scientific community.

Dr Steve Debus

My role is to conduct the biannual waterbird surveys in the Gwydir Selected Area. This involves going out in the field and identifying birds by sight and sound.

Shjarn Winkle

I work in stakeholder engagement and reporting. I help to compile and share our stories, write our reports and spend time in the field undertaking surveys.

Dr Leo Cameron

I am a Fisheries Project Manager/Fisheries Scientist. I frequently assist with the field work, data analysis and reporting. I also enjoy being a voice in the project design.

John St Vincent Welch

I schedule and run the Fisheries field surveys and handle data entry and data Quality Assurance and Control. I get in the boat and in the waders sampling fish in the most unlikely places.

Chris Bowen

I  undertake fisheries field survey, data entry and data Quality Assurance and Control, including ensuring sampling equipment is in good order.

Sam Lewis

I am an aquatic ecologist working with the Aquatic Ecology and Restoration Research Group at the University of New England. My role with Flow-MER involves conducting field surveys for a variety of aquatic indicators and providing support through laboratory and statistical analysis.

Ellen Ryan

I am involved with stakeholder engagement. I contribute to compiling and sharing of our stories as well as assisting with field surveys.

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    This page contains information specific to the Gwydir Commonwealth Environmental Water Holder (CEWH) Monitoring, Evaluation and Research Project. For further information about water use in the Gwydir catchment, please click here to visit the CEWH website.


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