Basin annual environmental watering priorities

Decisions on and use of Commonwealth environmental water

Support lateral and longitudinal connectivity and provide flows to maintain core wetland areas and provide refuge habitat

Commonwealth environmental water was committed to Victorian Rivers, with flows released in the Ovens, Campaspe, Loddon, Goulburn, Broken Creek (upper and lower) and Wimmera systems. Return flows were available for the bulk of these releases, with this water then used to provide longitudinal connectivity and meet outcomes in the mid-Murray and Lower Murray. The most significant releases were in the Goulburn River, where 320 GL was released targeting local outcomes related to riverbank vegetation and native fish. Return flows from these Goulburn releases were critical to support connectivity to the end of the system for outcomes in South Australia including releases to the Coorong. Elsewhere in Victoria, small volumes of Commonwealth environmental water released into the Wimmera (1.5 GL) were important for maintaining refuge pools and water quality conditions in the Wimmera River, which was experiencing its third consecutive very dry year.

In conjunction with other water holders, 231 GL of Commonwealth environmental water was delivered from Hume Dam as part of the Southern Spring flow. This water travelled over 2,000 km from Hume Dam to the Coorong, reconnecting the floodplain and the river, providing critical energy exchange of carbon and nutrients, and exporting more than 100,000 tonnes of salt from the lower Murray. The Southern Spring Flow provided food and shelter for native fish and other animals along the River Murray, in key wetlands and creeks in Barmah-Millewa and Gunbower Koondrook-Pericoota forests, Edward/Kolety-Wakool, Lake Kramen (Hattah-Kulkyne Lakes), and in Ramsar listed wetlands in Chowilla, Coorong and the Lower Lakes.

Winter flows into the Edward/Kolety-Wakool River system also contributed to maintaining connectivity (prevented cease-to-flow conditions from occurring), providing habitat for native fish and protected water plants from frost damage over hundreds of kilometres of river and creek channels.

Also in the Mid-Murray, Commonwealth environmental water supported in-channel flows through the creeks of Barmah Millewa Forest (8.1 GL in conjunction with other environmental water), Tuppal Creek (in partnership with New South Wales) as well as flows through Gunbower Creek (21.2 GL). Both actions aimed to provide habitat and food resources for native fish, as well as transport of nutrients and small aquatic animals and plant material.

Starting at Wyangala Dam in mid-September 2019, 17 GL of environmental water was provided to the Lachlan system to improve connectivity along hundreds of kilometres of the river all the way to the Great Cumbung. This flow also sought to improve connectivity between the main Lachlan River channel and Booberoi Creek. Booberoi Creek is of significant cultural value to First Nations Peoples. 16 gigalitres, or 43% of the Commonwealth environmental water carried over in the Lachlan system on July 1 2019 was quarantined by the NSW Government under the NSW Extreme Events Policy, which prioritises remaining water reserves towards meeting future critical human needs.

Welcome rain returned to the Condamine-Balonne catchment in January and February 2020. Around 163 GL of Commonwealth water for the environment was delivered downstream of Beardmore Dam, reconnecting rivers and floodplains along the Culgoa and Bokhara systems. These flows also reconnected important waterholes providing refuge, supporting native fish throughout the Lower Balonne and into the Barwon-Darling.

Throughout the year Commonwealth environmental water maintained longitudinal connectivity between the River Murray and the Coorong, providing constant fish passage and contributing 100% of flows through the barrages. Over 685 GL of Commonwealth environmental water flowed to the Coorong to provide critical estuarine habitat refuges in low flow, drought conditions.

Commonwealth, in conjunction with New South Wales environmental water supported lateral connectivity in the Murrumbidgee catchment through the use of water delivery infrastructure. Around 80.5 GL (48.3 GL Commonwealth) of environmental water was delivered to core wetland areas throughout the Murrumbidgee catchment providing critical refuge habitat for a range of water dependent animals, including migratory waterbirds and threatened species.

Mitigate irreversible environmental impacts associated with extended drought and prevent dry spell durations exceeding refuge tolerances

After 7 years of dry, around 90 GL of water flowed into the Ramsar-listed Narran Lakes/Dharriwaa. Up to half of the water that flowed into Narran Lakes is Commonwealth water for the environment. Narran Lakes/Dharriwaa is a place of immense cultural significance for local First Nations peoples. Queensland enforced flow management rules to reduce the amount of take by irrigators by 10% at critical dates during the flow event, demonstrating that regulations have the flexibility to achieve environmental outcomes in an unregulated system, while also recognising irrigation requirements.

Throughout the severe drought that continued in 2019 and early 2020, the CEWO worked with NSW delivery partners to provide replenishment and top up flows to key refuges in the Gwydir and Macquarie systems. In February 2020 the Gwydir Recovery Flow provided 3.7 GL of environmental water entitlements to rivers and wetlands across the Lower Gwydir, Gingham and Mallowa systems.

Rainfall between February and April 2020 enabled environmental water entitlements in the Macquarie system to provide 4.5 GL to help restore the condition of wetlands within the internationally significant Macquarie Marshes.

The consolidation of drought refuge habitat was a key priority for flows in the Lachlan during 2019–20. Flows into Booberoi Creek, Yarrabandai Lagoon and the Noonamah woodlands sought to provide drought refuges away from the main river channel for native plants, frogs and birds. Flows in the river channel sought to build on past watering actions, protect threatened Olive perchlet in Brewster weir pool and maintain the condition of the core area of reed beds in the Great Cumbung which need water every year.

In 2019 in the Lower Murrumbidgee region, many lakes, wetlands and local streams were drying up and stranding native wildlife. With limited wetland habitat available across the Basin due to drought conditions, approximately 80.5 GL of environmental water (approximately 48.3 GL Commonwealth) was delivered to maintain critical refuge habitats at sites throughout the Murrumbidgee catchment.

These flows prevented irreversible damage to the environment through preventing loss of wetland vegetation species by supporting native aquatic vegetation growth and providing critical refuge habitat to support the survival of waterbirds and native wildlife. In addition, flows were delivered to specifically target breeding of southern bell frogs at key sites in Gayini-Nimmie Caira, such as Eulimbah Swamp, where populations had declined and were at risk of local extinction. Commonwealth, in conjunction with NSW environmental water, successfully supported southern bell frog breeding, with tadpoles followed by metamorphs and juveniles having been observed (CSU 2020).

As drought during summer continued to impact inflows, salinity levels in the Coorong reached levels higher than sea water. This was due to relatively low volumes of water passing through the barrages and high evaporation. In autumn, additional environmental water from upstream watering actions enabled the barrage gates to open and allow freshwater to flow into the Coorong, reducing salt levels and creating a healthier environment for native fish and waterbirds. Continuous end of system flows of over 685 GL maintained estuarine conditions in parts of the Coorong close to the barrages, allowing them to function as refuges from the hypersaline conditions that persist further south in the Coorong lagoons.

Protect critical populations and support recovery of native fish by reinstating flows that promote key ecological processes across local, regional and system scales

The Gwydir Refuge flows provided 12 GL over 3 events from October 2019 through to January 2020, targeting large refuge pools in the Gwydir between Copeton Dam and Tyreel Weir, the Mehi between Tareelaroi and Combadello Weir and Carole Creek to near Garah. These flows maintained and provided access to refuge habitat in the drought, increasing connectivity and improving water quality in pools to assist native fish survival.

Part of the flows from the Lachlan spring pulse also targeted Olive perchlet habitat in Brewster weir pool. Oliver perchlet are a threatened native fish and the flows successfully maintained water levels and related habitat in Brewster weir pool throughout summer and autumn.

366 GL of in-channel Commonwealth environmental water releases were made in northern Victorian rivers (including Goulburn River, Lower Broken Creek, Gunbower Creek and other smaller streams) which helped generate base-level food resources for native fish (including waterbugs and biofilms) and created habitat and flow conditions to benefit native fish including Murray cod, trout cod, Macquarie perch, golden perch and eel-tailed catfish. The bulk of these releases (304 GL) occurred through winter-spring as part of the Southern Spring Flow.

231 GL of Commonwealth environmental water was delivered from Hume Dam in the Southern Spring Flow resulting in increased Murray cod recruitment. Congolli populations continued the strong trend of increase in recent years and good numbers of the endangered Murray hardyhead and Southern pygmy perch were also detected in Lake Alexandrina and numerous other sites. Both species expanded their range this spring.

Early monitoring results show the amount of zooplankton, an important food source for newly hatched fish, increased during the Southern Spring flow. Zooplankton are also crucial food for baby yabbies, crays and small fish so an increase in numbers means the River Murray food chain got a much-needed boost.

In the Edward/Kolety-Wakool River system the spring pulse was followed by a 'minimum stable flow' period which seeks to enhance the breeding conditions required for nesting fish species, like Murray cod, by preventing rapid drops in the river that may cause nest abandonment. Murray cod numbers are slowly recovering from the devastation of the 2016 flood and hypoxic river conditions experienced at that time. After the cod breeding season these flows were gradually scaled back, along with other actions in the Murray system, as the system was drying and conserving water for use in 2020–21 became a higher priority.

The Southern Spring Flow supported flows through the barrage fishways to provide a connection between the River Murray channel, Lower Lakes and Coorong and allow the seasonal movement of migratory fish species. Good numbers of both short-headed and pouched lamprey were detected moving from the ocean up the River Murray.

In 2020 the CEWH worked successfully with community and state agencies to support the successful relocation of threatened catfish from a drying lake to former habitat in Victoria (Ovens system). 20 ML of Commonwealth environmental water was delivered to the wetland as part of the relocation project. Environmental water (including 61 ML of Commonwealth environmental water) was also delivered to maintain suitable conditions for the endangered Murray hardyhead in Little Frenchman’s Creek on Wingillie Station during 2019–20. This follows translocation of around 800 Murray hardyhead from the Riverland, South Australia, to the site in 2019–20. Surveys throughout 2018–19 and 2019–20 have demonstrated that the translocation was successful, with the Murray hardyhead surviving and breeding following their release to Little Frenchman’s Creek.

In the Murrumbidgee catchment, Commonwealth (approximately 48.3 GL) in conjunction with New South Wales (approximately 32.2 GL) environmental water was delivered to sites throughout the catchment to maintain critical refuge habitat for native fish and other water dependent animals. These flows supported an overall high diversity of native fish, with flathead gudgeon, rainbowfish, smelt, bony bream, carp gudgeon and juvenile Murray cod being detected at monitored sites.

Maintain the diversity of the Basin’s waterbird population and provide flows to maintain or improve habitat and support breeding

The Lachlan spring pulse sought to provide foraging habitat for woodland birds and waterbirds at Yarrabanai Lagoon, Booberoi Creek, Noonamah woodlands and the Great Cumbung.

Watering of the Noonamah blackbox woodlands was undertaken in a joint watering action between New South Wales and the Commonwealth in 2019. Monitoring showed an increase in total waterbird abundance at this site and it continued to support large numbers of water birds in mid-January 2020.

The Southern Spring flow provided food and habitat for wetland birds from the Hume through to the Coorong. Flows re-wet 25% of the Barmah-Millewa forest, where bird surveys recorded Australasian bitterns booming at 12 of 16 sites. This is an important result for this endangered and elusive wetland-dependent waterbird. As dry conditions continued, it seems wetlands in the Barmah-Millewa forest were one of the most important sites in the country for bitterns this season. Southern Spring flows also contributed to providing suitable breeding habitat at the Lower Lakes where numerous waterbird species were recorded breeding including Australian white ibis, pied cormorant, and yellow billed spoonbill.

Due to the extended drought, many were concerned about the health of key habitat in the internationally significant Narran Lakes. Following recent flows into the Lakes, key waterbird breeding habitat has been inundated, with 4,500 hectares of the Ramsar site (within the Narran Lake Nature Reserve) watered.

The delivery of environmental water to core wetland sites throughout the Murrumbidgee catchment (Lowbidgee, mid-Murrumbidgee, Murrumbidgee Irrigation Area and Yanco Creek system) maintained habitat and supported breeding of a diversity waterbird species. This included threatened species, such as the Australasian bittern, brolga, magpie goose, blue-billed and freckled ducks; and migratory species, including wood sandpiper, sharp-tailed sandpipers, mash sandpiper, curlew sandpiper and long-toed stint. Breeding of royal spoonbills, darters, cormorants, white ibis, nankeen night heron were observed; and Australasian and Little bitterns were recorded booming.

Pumping of Commonwealth environmental water for the first time at Wanganella Swamp in the Yanco Creek System provided habitat for over 25 species waterbird species including brolga, red-necked avocet (the first observed in the district since 2010), red-kneed dotterel, white-necked heron, freckled duck, sharp-tailed sandpiper and Latham’s snipe.

Ramsar listed Tuckerbil Swamp in the Murrumbidgee Irrigation Area, was also a site that received Commonwealth environmental water.

Maintain extent and improve vegetation condition, particularly in areas of high habitat and conservation value

The Southern Spring flow had a positive response from wetland plants in the mid-Murray, improving river red gum and Moira grass health. It supported fringing and submergent native vegetation in the Lower Lakes, which in turn provides habitat for small-bodied native fish and frogs.

In partnership with New South Wales, flows into the Pollack (part of Koondrook-Perricoota Forest) also provided drought refuge for native birds and maintained the condition of native vegetation in the area.

Protecting the core reed bed areas of the Great Cumbung was a key priority for the use of water in the Lachlan during spring and again later in the year during autumn.

Watering of the Noonamah black box woodlands was undertaken, a joint watering action between NSW and the Commonwealth. 126 megalitres of Commonwealth environmental water was delivered from late October to early November 2019. The watering aimed to maintain the health of black box communities and provide refuge habitat for native animals, including water birds and frogs.

Watering events delivered throughout 2019–20 in the lower Goulburn River (311 GL of Commonwealth environmental water) were designed to provide germination, growth and maintenance conditions for in-stream and bankside vegetation. Promoting riverbank vegetation was targeted to help stabilise riverbanks and provide habitat for waterbugs.

Delivery of Commonwealth (approximately 48.3 GL) and New South Wales (approximately 32.2 GL) environmental water to maintain critical refuge habitat at sites throughout the Murrumbidgee catchment resulted in a positive response from native aquatic vegetation, with the growth of species such as spike rush, spiny mud grass, cumbungi, milfoil and nardoo. Two sites, Wanganella Swamp (Yanco Creek System) and Sunshower Lagoon (mid-Murrumbidgee) received Commonwealth environmental water for the first-time using pumping infrastructure. These sites were specifically targeted to prevent loss of aquatic vegetation due to lack of inundation from higher natural flows. Both sites had an excellent aquatic vegetation response, with monitoring at Sunshower Lagoon providing evidence of a significant increase in aquatic vegetation diversity compared to previous years, and observations at Wanganella Swamp reported the re-establishment of cumbungi and culturally significant nardoo. These 2 sites also provided refuge habitat for waterbirds, native frogs and turtles.

Category of expense

Fees and charges for entitlement holdings and allocation delivery b

Monitoring and evaluation activities

Development and maintenance of environmental registers and water accounting systems

Commonwealth environmental water delivery and planning projects, quality assurance activities, legal advice and market analysis

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