Environmental watering in the Lower Murray-Darling catchment in 2022-23
These Commonwealth environmental watering actions follow from the Water Management Plan 2022-23, having regard to Basin annual environmental watering priorities and, the Basin-wide environmental watering strategy.
This page will be updated as water use decisions are made by the Commonwealth Environmental Water Holder.
A summary of previous years' Commonwealth environmental water use in the Lower Murray-Darling river system is available at history.
For further information about Commonwealth environmental watering in the Lower Murray-Darling river system and the outcomes achieved, please refer to our Monitoring Reports.
| Watering action | Status of Commonwealth action |
|---|---|
| Lower Murray and end of system flows | In progress |
| Lower Darling/Baaka flows | In progress |
| Great Darling Anabranch | In progress |
| Hattah Lakes | Complete |
| Weir Pool Manipulation and SA Floodplains | Complete |
| South Australian Wetlands | In progress |
Lower Murray and end of system flows
Status: In progress
Note: The River Murray has been experiencing high flows and flooding. We are responding to the conditions and avoiding delivering water where it may worsen third-party effects from flooding.
Commonwealth environmental water is planned to be delivered where required, once natural high flows decrease. In wet conditions, water for the environment has important ecological benefits. This includes assisting the recovery of wetlands from the impacts of the last drought, supporting waterbird breeding, helping native fish migrate or providing refuge from any negative impacts of natural flooding (such as low-oxygen blackwater).
About the watering
The Commonwealth’s held South Australian allocation of 162 GL contributes to baseflows in the Lower Murray and is delivered as part of the South Australia entitlement across all months of the year. A portion of this water is used in South Australian Wetlands (see details below).
This water delivery may be complemented by up to 250 GL of water delivered to South Australia to provide water to floodplain and wetland areas that have been dry since 2016, support flowing water habitat for native fish and to support connecting flows to the end of the system. Additional Commonwealth environmental water will also reach the Lower Murray as moving downstream from watering actions in tributaries in upstream states such as the Upper Murray (see above), Goulburn, Lower Darling/Baaka and Murrumbidgee rivers.
Commonwealth environmental water is targeting the following outcomes in the Lower River Murray channel and floodplains:
- Support processes such as primary and secondary production, mobilisation and transport of nutrients, carbon cycling and biotic dispersal throughout the River Murray catchment, which underpin food webs and are essential to the health of the system.
- Provide native fish with in-stream habitat and connect the river channel with wetlands and anabranches to maintain native fish condition and provide opportunities (where feasible) for recruitment, spawning and movement.
- Increasing inundation of floodplain and wetland areas that have been dry since 2016;
- Maintain water quality and reducing risks of stratification and algal blooms by increasing the extent and duration of flowing water in the river channel.
Water delivered to the Lower Lakes and Coorong is targeting the following outcomes:
- Support flows through the barrages to provide a connection between the River Murray channel, Lower Lakes and Coorong and allow the seasonal movement of migratory fish species.
- Maintain favourable salinity levels in the north lagoon of the Coorong to support estuarine fish.
- Support native vegetation fringing and within the Lower Lakes, which in turn provides habitat for small-bodied native fish and frogs.
- Provide habitat and food to support waterbirds.
- Provide water quality benefits for the river and Lower Lakes through salt export from the River Murray.
- Contribute to the maintenance of habitat, water quality, water level in both the Lower Lakes and Coorong.
River Murray at Waikerie and pelicans on the Coorong. Photos: CEWO
Lower Darling/Baaka flows
Status: In progress
The last year has seen high inflows from the northern Murray-Darling Basin via the Barwon-Darling (Baawan-Baaka) into the Menindee Lakes.
After successive years of high flows and successful fish breeding events, extremely large numbers of fish have congregated in the Menindee reach of the Darling River. With flood waters receding, hypoxic blackwater conditions caused a large-scale fish death event in the lower Darling-Baaka River in autumn 2023.
NSW and Commonwealth agencies have been working together to do what we can to improve water quality in the lower Darling/Baaka River. Agencies have been responding to the conditions and local advice, adjusting the timing, size and location of releases from the Menindee Lakes into the lower Darling River, including releasing environmental water.
Unfortunately, under these conditions there are limited intervention options, however, agencies are continuing to monitor the situation and respond where possible.
For more information on the current fish death response, please see water quality updates on the NSW Hypoxic blackwater page.
Going forward, small volumes of environmental water may be used to ‘top up’ baseflows in the river channel for environmental outcomes during winter, to support the surviving fish population.
Any environmental releases into the lower Darling/Baaka are expected to support the dispersal of juvenile golden perch that spawned upstream of the Menindee Lakes into the lower Darling/Baaka and ultimately the River Murray.
Environmental watering in 2022-23 will continue to be informed by previous monitoring results as well as additional monitoring expected to be undertaken during the year.
For more information and updates during the event see: Lower Darling-Baaka and Great Darling Anabranch water updates 2021-2023
Monitoring results 2020-21 are available at: Monitoring native fish response to environmental water delivery in the lower Darling River 2020-2021. Results from 2021-22 will be published once finalised.
Fish surveys found young golden perch have travelled from the northern tributaries and are using the Menindee Lakes as nursery habitat. Photo: DPI Fisheries
Great Darling Anabranch
Status: This action is in progress
About the watering
The Great Darling Anabranch has been flowing since spring 2021. A combination of water for the environment and operational releases saw the first Great Darling Anabranch flows in almost five years. The flows have continued to February 2023 via floods from the northern Murray-Darling Basin.
Commonwealth environmental water is now providing baseflows down the Great Darling Anabranch. These flows will continue to benefit the vegetation communities of the Anabranch, while also transporting juvenile fish to the River Murray.
For more information and updates during the event see: Lower Darling-Baaka and Great Darling Anabranch water updates 2021-2023
Hattah Lakes
Status: This action is complete
About the watering
During 2021-22, the majority of the Ramsar-listed Hattah Lakes complex received a significant environmental delivery. This coincided with higher-than-average natural spring flows in the River Murray. This watering action followed a system priming flow in winter 2021 (after the main lakes has undergone a drawdown and drying phase since 2017) and had significant benefit for floodplain and aquatic vegetation and waterbirds.
Taking advantage of wet conditions and natural flows that entered the Hattah Lakes complex over winter, water for the environment has again been delivered to the lakes in spring 2022.
The purpose of the event was to build on last year’s flows to top-up and fill most of the lakes, to promote river red gum and aquatic vegetation growth and condition, support waterbird and small-bodied native fish breeding and provide nutrients and other floodplain material back into the River Murray channel to boost food-webs in the river.
Commonwealth environmental water was not required for this watering action, as unregulated entitlements held by The Living Murray and Victorian Environmental Water Holder were able to be used opportunistically in conjunction with the high River Murray flows, preserving regulated Commonwealth water allocations for use in other watering actions described on this page.
Weir Pool Manipulation and SA floodplains
Status: This action is complete
About the watering
Commonwealth environmental water was assigned to support weir pool manipulation at Locks 2, 4, 5, 7, 8, 9 and 15. The lowering and raising of weir pools aims to provide increased variation in river flows, which underpin important ecological functions, with benefits for both in-stream habitats (by increasing river flow when weir pools are drawn down) and low-lying floodplain areas (by inundating wetlands that sit slightly above normal weir pool levels, and recreating a more natural wetting and drying pattern for pools that are normally connected to weir pools).
Commonwealth environmental water was also assigned to support the watering of the Pike and Katarapko floodplains through the operation of floodplain infrastructure. Watering these floodplain systems aims to improve the health and condition of important tree communities such river red gums, black box and lignum and support populations of frogs, water birds and yabbies. Watering at these floodplain sites built on the outcomes from watering in 2020-21 and 2021-22.
The natural high flows in the River Murray has meant that a number of actions have been completed with the assistance of natural flows.
Photos showing benefits of raising Lock 5 weir pool in South Australia. Photos: DEW
South Australian Wetlands
Status: In progress
About the watering
As part of ongoing partnerships, Commonwealth environmental water will be made available to:
- Banrock Station (up to 6,167 ML over five years to 2022-23, as part of a continued commitment between the CEWH and Banrock Station)
- Calperum Station (up to 2,468 ML in 2022-23 as part of a five-year partnership to 2024-25)
- Renmark Irrigation Trust (up to 494 ML, as part of a continued commitment between the CEWH and Renmark Irrigation Trust)
- Murraylands and Riverland Landscape Board (up to 7,579 ML in 2022-23) as part of a five-year partnership to 2024-25
Delivery of Commonwealth environmental water to SA wetlands was limited in 2023-24, with many wetlands receiving water naturally from high River Murray flows. A small amount of environmental water is being delivered to wetlands adjacent to the Lower Lakes that have not been naturally inundated.
Watering events are being implemented across South Australia with the assistance of Traditional Owners, private landholders, Landcare and community groups, local councils, the Murraylands and Riverland Landscape Board and the South Australian Department for the Environment and Water.