Environmental Flows

Macquarie River Valley 2022–23 Water Use Update 1
March 2023

A combination of water from Burrendong Dam, rainfall and
stream flows into the Macquarie River saw flows across
220,000 hectares of the iconic Macquarie Marshes in Spring
2022. This included outer floodplain areas that did not
receive water in 2021 or 2016.

Large volumes of water flowing into the Macquarie Marshes
provided ideal conditions for waterbird breeding. Vast
colonies of breeding ibis, egrets and herons started to form
in Spring 2022, along with spoonbills, magpie geese,
cormorants, and a range of non-colonial species like ducks.

Lower Balonne flow event update February 2023

Triggered by the wetter conditions in recent years,
thousands of waterbirds are breeding at the
internationally significant Narran Lakes in the Lower
Balonne region for the second year in a row.
This is the second time in 10 years that waterbirds have
bred at Narran Lakes. It is an important event for the
recovery of waterbird populations, which have been in
major decline across the Basin for the last forty years.

Lower Balonne Flow Updates 2021-2022

Good flows in the Lower Balonne with more to come!

With all the rain and flows about, Lower Balonne rivers and floodplains are primed. Landscapes are rebounding from the drought. Since November 2021, more than 1,646 gigalitres (GL) of water has flowed past St George, including 131 GL of Commonwealth water for the environment. This is higher than the flows that reached Dharriwaa in 2020 (when 1,442 GL passed St George). Flows reached the internationally significant Narran Lakes (Dharriwaa) in late 2021 inundating core waterbird breeding habitat. Around 65 GL has reached the Darling (Baaka) River so far benefiting local communities and other nationally significant wetlands downstream.

Read More Here

Sentinel image of Dharriwaa – December 2021. Source: MDBA
Large numbers of Sharp-tailed sandpipers over Clear Lake in November 2021. Photo: Pat Johnston, NSW NPWS volunteer.

Flows in the Macquarie/Wambuul System 2021-2022

The iconic Macquarie Marshes has supported some of the largest colonial waterbird breeding events in Australia. The most recent major nesting events occurred in 2016–17 and previously in 2010–11.

As at December 2021, the largest colonies in the Marshes were made up of ibis (Australian white, strawnecked and glossy) and combined egrets and night herons (primarily intermediate and eastern great egrets).

There has been a long-term trend of declining waterbird populations across the Murray–Darling Basin so these large colonies are critical to sustaining and ultimately recovering waterbird populations.
The NSW Department of Planning and Environment and the University of NSW continue to monitor the size and health of the colonies, now numbering around 20 colonies, ranging between 30 and 15,000 nests in size.

Flows in the Gwydir System 2020/2021

The 2020-21 water year started with a mostly drier six months from July to December 2020, including a record dry November. Rainfall events then created downstream tributary flows in rivers and creeks from late December onwards.

These more regular rainfall events continued, and created both steadier low flows, along with at times, higher flow events in the Gwydir systems, with six months to June of overall well above average rainfall. Very heavy local and upper catchment rainfall led to a major flooding event in late March 2021.

From late December to mid-March small environmental water deliveries totaling around
23.1 GL were made from ECA and Held Environmental Water (HEW from NSW and
Commonwealth high security, general security and supplementary licences held for the


Northern Waterhole Top-up 2020/2021

The last four years have been the driest on record across much of the northern Murray-Darling Basin, despite rain earlier in 2020, and the current La Nina. Parts of the Barwon River have not flowed for over 60 days, and the river is drying back to waterholes.

Because the Barwon River has stopped flowing for two months already, Commonwealth and NSW water for the environment will be delivered to 200+ km of the river system to help our native fish survive through the summer. The water will be released from Pindari and Copeton dams and will flow down the Macintyre River and Gil Gil Creek in the Gwydir catchment.

201222 Northern Waterhole Top-up – Flow Update 1


Barwon at Mungindi Weir 8 January 2021 

Macquarie River Valley Update 2020

19th October 2020 – The delivery of Commonwealth and NSW water for the environment from Burrendong Dam has begun, with water making its way through the mid-Macquarie River and into the Marshes. The flows aim to support the Murray cod nesting season in the mid-Macquarie River, help with drought recovery in the Macquarie Marshes, and improve connection with the Barwon River.

2020-21 Macquarie Water Use – Update 1

2020-21 Macquarie Water Use_Update 2

2020-21 Macquarie Water Use-update-3

Macquarie River Murray Cod Monitoring: Progress Update

Monitoring found that Murray cod successfully spawned in the mid-Macquarie River during the delivery of water for the environment in spring. Preliminary analysis found larvae of at least five fish species and crustaceans. These included Murray cod, freshwater catfish, yabbies, and mussels. Whilst larval carp were also detected, they were in much lower numbers than Murray cod larvae. The water temperature was warm enough for spawning. macquarie-river-murray-cod-monitoring-progress-update-dec-2020

Environmental water and conditions in the Gwydir system –  Oct20/Jan21

Natural flows have been occurring along the Gwydir system after heavy rainfall events in late January and
February 2020 resulted in some higher flows and then natural flows continued with smaller events up into
October 2020.

Community update Gwydir 26 October 2020

Flows are continuing at a reducing rate in the Carole-Gil from the last of the block release, including the CEWO Northern Waterhole Top-up delivery. Portions of natural tributary flows that are protected by rules and conditions have been providing flows along systems including the portion of these natural flows that was made available for supplementary irrigation take under licences. This flow has been along the main and lower Gwydir river, the Mehi, Moomin, and Carole – Gil Gil systems. These natural flow events are from tributary inflows into the Gwydir system downstream of Copeton Dam.  A portion of these natural flow events (also called supplementary events when used for irrigation take) is protected by rules and conditions from extraction, and that portion is called planned environmental water (PEW). There has been smaller PEW inflows into both the Lower Gwydir and Gingham watercourses, including from the rule protecting a base amount of low natural tributary flows, when they occur, for the Gwydir Wetlands. Core watercourse and wetland areas in the Gingham from Tyreel down to the Gingham Waterhole have received PEW inflows, with the Gingham Waterhole starting to fill on Sunday 10 January after almost completely drying out. The Lower Gwydir river system from South Arm to downstream of Millewa gauge area and the downstream watercourse and wetland areas have received flows on Belmont, Retreat, Old Dromana, and small parts of Birrah, Curragundi and Troy

Lower Balonne flow 2020

A collaborative effort between governments, local water licence holders and community representatives will see more water stay in our rivers on the back of recent rains in the area. The increased flows will reach the parched Lower Balonne system, including the internationally significant Narran Lakes, in early March.


Lower Balonne Flow Update 2 v2.

Lower Balonne Flow Update Monday 11 January 2021 Rainfall resulted in a local inflow volume of 500 megalitres in the last week of December 2020. The inflows were accounted for as water for environmental, stock and domestic  purposes (‘ESD’ water). Rainfall in the mid-catchment (Condamine-Balonne) in the week beginning 4 January 2021 has resulted in further inflow to Beardmore Dam at daily rates above 730 megalitres per day.

Gwydir Refuge Pool Flow 2019

Water for the environment is flowing through parts of the Gwydir valley to maintain critical river pool habitat for native fish. Very hot and dry conditions and limited water holdings will see water for the environment prioritised to keep large refuge pools in good condition. These low flows will target parts of the Gwydir and Mehi Rivers and the upper Carole Creek.

Gwydir refuge pool flow nov2019 update 1

Gaygay (catfish) started building nests in November after flows from Event #1 reached the Mehi River.

Flows from Event #1 reached Tyreel, Combadello Weirs and Carole Creek near Garah in early November.

Flows for Event #2, which is smaller than Event #1, commenced 9 December to top-up some important river pools in the Gwydir and Mehi systems.

Gwydir refuge pool flow dec2019 update 2

Northern Fish Flow 2018-19

The Barwon River in the northern Murray-Darling Basin has not flowed for over 200 days, drying back to poor quality waterholes, threatening the survival of native fish in the region.

To help native fish survive the drought the Commonwealth Environmental Water Office in partnership with the NSW Office of Environment and Heritage and other NSW agencies is releasing water for the environment from April to June to replenish critical waterholes.

Northern Fish Flow Update # 1

Northern Fish Flow Update # 2

Northern Fish Flow Update # 3

Northern Fish Flow Update # 4

Northern Fish Flow Update # 5

Water for native fish Mehi River flow

CEWH media Release 20190415

2018-19 Macquarie River and Marshes environmental watering

Commonwealth and NSW environmental water holders have agreed to deliver environmental water to the mid-Macquarie River and Marshes between winter and summer 2018-19 to maintain the ecological health and resilience of assets in the catchment. Environmental water will also help to maintain and improve the condition of wetland vegetation, and will provide benefits for native fish and waterbirds.

Update 1 – September 2018

Update 2 – October 2018

Update 3 – December 2018

The Northern Connectivity event from May 2018

Commonwealth and NSW environmental water holders have agreed to release water from storages in the Northern Murray-Darling Basin to support the environmental health of river systems including the Barwon-Darling down to Wilcannia and beyond. Come, learn and share about this important, participate in activities with river scientists and meet with other people who care about the health of these important rivers, and the fish and ecosystems which depend on them.







northern-connectivity-update- 7


Lachlan River Watering Event 2018-2019

Water is being delivered to the Lachlan River below Wyangala Dam in response to recent system inflows (runoff) triggered by rainfall. The event will assist to build on the inflows to mimic seasonal variability that is a natural occurrence in the Lachlan River and connecting wetlands including the Great Cumbung Swamp.

Lachlan_Dec 18

Namoi River 2018-2019

The Commonwealth Environmental Water Holder agreed to deliver environmental water to the lower Namoi River between November and December 2018, to protect the ecological health and resilience of aquatic ecosystems in the catchment. In particular, environmental water will be delivered to reconnect and maintain refuge pools, and to support native fish communities.

Namoi River 18-19 Update 1

Namoi River 18-19 Update 2

Namoi River 18-19 Update 3

Namoi River 18-19 Update 4

Gwydir Wetlands  2018-2019

The Commonwealth and NSW environmental water holders have agreed to deliver up to 60,000 megalitres (ML) of environmental water to the Gingham and Lower Gwydir wetlands in 2018-19. This watering event aims to help maintain the health and resilience of the Gwydir Wetlands during the current dry conditions. The delivery will support habitat and food sources for native fish, frogs, turtles, and waterbirds. Environmental water delivery commenced in mid-July, with the initial delivery pausing in late October to allow for harvest. Once harvest is complete environmental flows will likely resume during summer to build on outcomes from the spring delivery.

Gwydir Wetlands 18-19 Update 1

Gwydir Wetalnds 18-19 Update 2

Gwydir Wetlands 18-19 Update 3

Mallowa Wetlands 2018-2019

Up to 20,000 ML of Commonwealth water for the environment will be delivered into the Mallowa Creek during the 2018–19 water year. This water will improve the health of wetland vegetation along the length of the system. Water for the environment that is currently being delivered will meet the water requirements of more than 2,000 hectares of remaining wetland vegetation and enhance the condition of waterbird feeding habitat. These flows also support native fish populations along the Mehi River upstream of the Mallowa Creek offtake.

Mallowa Wetlands 18-19 Update 1

Mallowa Wetlands 18-19 Update 2

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