History - Gwydir

Commonwealth environmental watering actions follow from the Commonwealth Environmental Water Management Plan: Gwydir Valley 2020-21 having regard to Basin annual environmental watering priorities and the Basin-wide environmental watering strategy

Commonwealth environmental watering actions follow from the Commonwealth Environmental Water Portfolio Management Plan: Gwydir Valley 2019-20 having regard to Basin annual environmental watering priorities and the Basin-wide environmental watering strategy.

Environmental watering during 2018–19 sought to promote recovery of wetland vegetation, provide habitat for threatened species as well as survival and reproduction opportunities for a range of waterbird and native aquatic species (e.g. fish, frogs, turtles, invertebrates). Water was also delivered to protect critical refuge habitat during extreme dry river conditions.
In-stream watering in the valley aimed to contribute to maintaining drought refuge, wetland inundation, hydrological connectivity, in-stream habitat condition and diversity, water quality, primary productivity, native aquatic species condition and reproduction.
During the year a total of 62,150 ML of Commonwealth environmental water (plus an additional 52,000 ML from New South Wales Environmental Contingency Allowance) was delivered to sites in the Gwydir, including:

• 60 GL (30 GL Commonwealth) of water for the environment to the Gwydir Wetlands. Environmental water was provided to support water dependent semi-permanent wetland communities by contributing through a proactive watering of wetland inundation which reached all land parcels of the Ramsar sites.  
• 16.9 GL of Commonwealth water was delivered to the Mallowa watercourse as a proactive flow to support hydrological connectivity of these wetlands and for further recovery of vegetation extent and condition. This system and its wetlands are dependent on environmental water to ensure their continued health.
• 8GL (4 GL Commonwealth) of water for the environment was delivered down the Mehi river and Carole creek to provide critical drought refuge after extended periods of low and no flow. This watering action comprised of a small ramping base flow from early April 2019. The primary purpose of this flow was to ensure the continued survival of native fish.
• 28.6 GL (10.6 GL Commonwealth) water for the environment was delivered from April – June 2019, as part of the Northern Fish Flow, which has provided drought refuge for native fish in the Mehi and Barwon Darling River. The flow reached past Brewarrina in the Barwon-Darling and helped to support conditioning and maintenance of native fish populations in the Gwydir Valley, by maintaining water quality and providing access to food and habitat.
• 600 ML of water was pumped to Ballin Boora through landholder infrastructure to environmental water to the end of the creek system and connect to the Mehi River. The action supported recovery of vegetation extent and condition, including for endangered ecological communities (coolabah open woodland), and provide habitat for a range of waterbirds and native aquatic species.

About the watering

The overall objectives for wetlands in the Gwydir during 2017-18 was to promote recovery of wetland vegetation, provide habitat for threatened species as well as survival and reproduction opportunities for a range of waterbird and native aquatic species (e.g. fish, frogs, turtles, invertebrates).

In-stream watering in the valley aimed to contribute to flow variability, hydrological connectivity, in-stream habitat condition and diversity, water quality, primary productivity, native aquatic species condition and reproduction.

During the year a total of 28,290 ML of Commonwealth environmental water (plus an additional 18,658 ML  from New South Wales Environmental Contingency Allowance) was delivered to sites in the Gwydir, including:

• Environmental water was provided to support water dependent semi-permanent wetland communities by contributing through a reactive watering approach (where supplementary access announcements triggers the release of held environmental water to offset extraction from natural events).
• Commonwealth environmental water together with New South Wales environmental water provided early season benefits along the upper Gwydir River in 2017-18. This watering action comprised of a small fresh over ten days from late August 2017. The primary purpose of this flow was to stimulate early season in-channel productivity in the Gwydir River, also including downstream in the Carole Creek and the Mehi River. Other secondary outcomes included downstream hydrological connectivity, and end of system flows into the Barwon River.
• Commonwealth environmental water together with NSW environmental water was used in spring 2017-18 to provide the best possible conditions for native fish breeding in the Gwydir River. A small stable baseflow was provided along the upper stretches of the Gwydir River, with downstream benefits expected for the Lower Gwydir River, Gingham Watercourse, Mehi River and Carole Creek. The ecological outcomes sought from this flow were to provide opportunities for fish movement breeding and recruitment activity, particularly for the freshwater catfish. Other secondary outcomes included downstream hydrological connectivity, and end of system flows into the Barwon River.
• Environmental water that was then delivered in April 2018, as part of the northern connectivity event, has provided an end of system pulse to the Barwon River and helped to support conditioning and maintenance of native fish populations in the Gwydir Valley, by providing access to food and habitat.

About the watering

Environmental watering during 2016-17 sought to follow natural cycles of drying and wetting by contributing to wetland watering, and in-stream flows. Water was also delivered to protect critical refuge habitat during extreme dry river conditions.

Up to 39.45 GL of Commonwealth environmental water was made available for in-stream and wetland watering events across these sites during 2016-17.

During the year a total of 22,847 ML of Commonwealth environmental water (plus an additional 21,800 ML from New South Wales Environmental Contingency Allowance) was delivered to sites in the Gwydir, including:

• 9,000 ML (plus an additional 21,000 ML of NSW ECA) was delivered to the Gwydir Wetlands to maintain water dependent vegetation in low lying wetland areas to support hydrological connectivity of these wetlands and for further recovery of vegetation extent and condition.
• 7,496 ML was delivered to the Mallowa watercourse to maintain high vegetation species richness and cover.  Inundation was stimulated by winter/ spring rainfall and local runoff.
• A total of 1,351  ML of Commonwealth environmental water was provided during natural flow events to support the highly water dependent semi-permanent wetland communities by contributing through a reactive watering approach (where supplementary access announcements triggers the release of held environmental water to offset extraction from natural events).
• 5,000  ML of environmental water was protected during a supplementary access period for flows to the Mehi River below Gundare Weir. This action aimed to make water available to enhance flow variability, hydrological connectivity, in-stream habitat condition and diversity, water quality, primary productivity, native aquatic species condition and reproduction.

About the watering

The Gwydir and Mallowa Wetlands, Mehi River and Carole Creek are important environmental assets in the Gwydir River Valley and the Murray-Darling Basin. Environmental watering during 2015-16 sought to follow natural cycles of drying and wetting by contributing to wetland watering, and in-stream flows. Water was also delivered to protect critical refuge habitat during extreme dry river conditions.

Up to 39.45 GL of Commonwealth environmental water was made available for in-stream and wetland watering events across these sites during 2015-16. During the year a total of 8,400 ML of Commonwealth environmental water (plus an additional 4,750 ML from New South Wales Environmental Contingency Allowance) was delivered to sites in the Gwydir, including:

• 3,486 ML was delivered to the Mallowa watercourse during a naturally triggered flow event to support hydrological connectivity of these wetlands and for further recovery of vegetation extent and condition.
• A total of 2700 ML of environmental water (1,350 ML of Commonwealth water and 1,350 ML of New South Wales Environmental Contingency Allowance) was provided during natural flow events to support the highly water dependent semi-permanent wetland communities by contributing through a reactive watering approach (where supplementary access announcements triggers the release of held environmental water to offset extraction from natural events).
• 964 ML of environmental water was protected during a supplementary access period for flows to the Mehi River below Gundare Weir. This action aimed to make water available to protect critical refuge habitat during dry river conditions to contribute to flow variability, hydrological connectivity, in-stream habitat condition and diversity, water quality, primary productivity, native aquatic species condition and reproduction.
• 6,000 ML (2,600 ML of Commonwealth water, and 3,400 ML of New South Wales Environmental Contingency Allowance) to provide hydrological connectivity to in-stream habitat across the catchment, to ensure the persistence of pools as refuge; and to reduce the risk of degrading water quality conditions (particularly low dissolved oxygen levels). 

About the watering

The Gwydir and Mallowa Wetlands, Mehi River and Carole Creek are important environmental assets in the Gwydir River Valley and the Murray-Darling Basin more broadly. Complementary watering actions across each of these sites sought to provide stream flows and wetland connectivity to contribute to a range of environmental outcomes. These watering actions contributed to maintaining vegetation condition, protecting key refuge sites and supporting fish and waterbird communities.

Up to 75 GL of Commonwealth environmental water was made available for in-stream and wetland watering events across these sites during 2014-15. During the year a total of 56,639 ML (plus an additional 29,895 ML from New South Wales  Environmental Contingency Allowance) was delivered to sites in the Gwydir, including:

• 30,000 ML (plus an additional 29,895 ML of NSW ECA) was delivered to the Gwydir Wetlands to maintain water dependent vegetation in low lying wetland areas and 9,667 ML was delivered into the Mallowa Wetlands to support hydrological connectivity of these wetlands and for further recovery of vegetation extent and condition.
• 13,316 ML and 3,656 ML was delivered to the Mehi River and Carole Creek (respectively) to support in-stream ecological function and nutrient cycling, including contributing to native fish migration (residual flows provided positive downstream environmental outcomes including activation of the Brewarrina fishway for a period of ten days).

Monitoring and evaluation of the outcomes from these watering actions is being undertaken by the Commonwealth Environmental Water Office’s Long-term Intervention Monitoring Provider in the Gwydir catchment.

Media

Gwydir valley to receive environmental water – Media Release – 30 October 2014

Environmental watering in the Gwydir wetlands 2013-14

About the watering

Up to 25 GL of Commonwealth environmental water was made available to augment unregulated flows and inundation of the Gwydir Wetlands between September 2013 and April 2014. The total volume of Commonwealth environmental water used was dependent on seasonal conditions and rainfall.

This watering action aimed to support the ongoing recovery of the wetlands and build resilience by contributing to:

• maintaining the condition of permanent and semi-permanent wetland native plant communities
• promoting waterbird survival, condition, reproduction and fledgling
• promoting fish movement, nutrient and carbon cycling, and primary production.

If a bird breeding event commences, this environmental water may also be used to contribute to maintain reproduction and recruitment for colonially nesting water birds in the wetlands.

Native woodlands in the Gwydir wetlands Photo: Clare d'Arcy © CEWO

The wetlands contain native plant communities such as marsh club rush, water couch, river cooba and lignum. On the floodplain, coolibah woodlands fringe the wetlands and form extensive woodlands in a number of areas. These plants have many of their natural processes, such as flowering, seeding and germination, determined by the amount of water that is available to them.

These plant communities provide habitat to tens of thousands of waterbirds, including the intermediate egret, little egret, nankeen night heron, glossy ibis, straw-necked ibis and cormorants, that breed throughout the wetlands. The wetlands also provide habitat for many types of frogs, fish and insects that, in turn, are food for the nesting waterbirds.

The watering action was made possible by the collaboration of a wide range of stakeholders including the NSW Office of Environment and Heritage, State Water Corporation, local environmental water advisory committee and landholders.

Environmental watering in the Mallowa Wetlands 2013-14

About the watering

Mallowa Wetlands, Gwydir catchment. Photo by Simon Banks (CEWO)

Up to 15 GL of Commonwealth environmental water was made available to provide a third successive year of inundation in the Mallowa Wetlands between September 2013 and April 2014. This watering action aimed to support the ongoing recovery of the wetlands and build resilience by contributing to:

• maintaining the condition of permanent and semi-permanent wetland native plant communities (e.g. water couch, spike rush, marsh club rush and lignum ;
• promoting waterbird survival, condition, reproduction and fledgling
• promoting fish movement, nutrient and carbon cycling, and primary production.

The Mallowa Wetlands comprises 1,642 hectares of native coolibah, lignum and river cooba plant communities. These plants have many of their natural processes, such as flowering, seeding and germination, determined by the amount of water that is available to them.

The wetlands provide valuable bird breeding habitat and food for a diverse range of waterbirds, including jabiru, brolga, egret and ibis, and are an important link to the range of habitats provided by the greater Gwydir Wetlands. As well as supporting a number of different types of birds that are listed under international conservation agreements.

The Mallowa Creek system also provides habitat for many different types of threatened native birds. These include Grey-crowned babbler, hooded robin, brown treecreeper, bush stone curlew, square-tailed kite, glossy black cockatoo, Australian bustard, diamond firetail and grey falcon.

This watering action has been made possible by the collaboration of a wide range of stakeholders including the NSW Office of Environment and Heritage, State Water Corporation, the local environmental water advisory committee and landholders.

See also: NSW Office of Environment and Heritage media release Environmental Water Release to Mallowa Creek, Gwydir valley - 27 September 2013

Mallowa Wetlands, Gwydir catchment. Photo by Simon Banks (CEWO)

Environmental watering in the Mehi River and Carole Creek 2013-14

About the watering

The Mehi River, Gwydir catchment.
Photo: Clare d'Arcy © CEWO

For the first time environmental water was provided to the Mehi River and to Carole Creek in the Gwydir catchment to provide a greater diversity of flows to maintain habitat for native animals, particularly native fish.

Up to 15 GL and 5 GL of Commonwealth environmental water was made available for the Mehi River and Carole Creek respectively. The flows, targeting the Mehi River downstream of Combadello Weir and Carole Creek downstream of the off-take, were delivered in late October 2013.

These watering actions aimed to improve the natural character of in-stream freshes with a slower, more natural rate of recession and were expected to contribute to the following outcomes:

• supporting fish movement, carbon/nutrient cycling, and primary production processes; and
• supporting the condition of native aquatic animal communities (including native fish and invertebrates) and native fish larval abundance.

These watering actions have been made possible by the collaboration of a wide range of stakeholders including the NSW Office of Environment and Heritage, NSW Department of Primary Industries (Fisheries), NSW Office of Water, State Water, the University of New England, local environmental water advisory committee and landholders.

See also: CEWO Media Release Environmental water for the Gwydir's native fish

Jabiru, Gwydir catchment. Photo: Clare d'Arcy © CEWO

Environmental watering in the Mallowa Wetlands 2012-13

About the watering

This was the first time environmental water was provided to the Mallowa Wetlands. This watering action contributed to support the ongoing restoration of native wetland plant communities and maintain habitat for native animals. It occurred over summer which was in keeping with the natural seasonality of river flows and the water needs of environmental assets in the Gwydir catchment.

This watering action was made possible by the collaboration of a wide range of stakeholders including the NSW Office of Environment and Heritage, State Water Corporation, the local environmental water advisory committee and landholders.

Environmental watering in the Gwydir wetlands 2012-13

About the watering

Straw-necked ibis chicks. Photo: Andrew Huxham © CEWO

Environmental water was provided to the Gwydir Wetlands to support the ongoing restoration of native wetland plant communities and maintain habitat for native animals.

The watering action occurred over summer which was in keeping with the natural seasonality of river flows and the water needs of environmental assets in the Gwydir catchment.

This environmental watering action was made possible by the collaboration of a wide range of stakeholders including the NSW Office of Environment and Heritage, State Water Corporation, local environmental water advisory committee and landholders.