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Wetlands reconnection flow Murrumbidgee River and Yanco Creek - environmental water delivery now complete

River users in the Murrumbidgee Valley are advised that the delivery of environmental water from Burrinjuck and Blowering dams, to enable a reconnection flow to Murrumbidgee wetlands, has now successfully ceased.

The flow commenced on 24 July 2017 with the peak of this release continuing down the Murrumbidgee and Yanco Creek systems. Numerous wetlands have been re-connected using nearly 220 gigalitres of water held by the NSW Government and the Commonwealth Environmental Water Holder.

This water has helped to improve breeding and foraging habitat for native fish and birds and to stimulate growth of wetland plants, which helps to improve water quality.

Water managers from the NSW Office of Environment and Heritage (OEH), along with WaterNSW will continue to monitor the flow as it moves downstream.

OEH ecologists have commenced monitoring the water delivery event and evaluating the responses of different animals and plants in the connected wetlands.

The delivery of this water has been a co-operative effort involving NSW OEH, WaterNSW, the Commonwealth Environmental Water Holder, Murrumbidgee Irrigation Limited, Coleambally Irrigation, DPI Water and landholders along the Murrumbidgee River system.

For additional information: Real-time water data (for River heights).

Wetlands Reconnection Flow – Murrumbidgee River and Yanco Creek, planned for July 2017

Water will be ordered for delivery into the Murrumbidgee River from Burrinjuck and Blowering Dams from 24 July.

River users will see a rise in the river level for approximately 17 days, however the water will remain well within the river channel.

WaterNSW has advised a need to increase dam releases to reach 22,000 megalitres per day (4.0 metre gauge height) at Wagga Wagga to meet both irrigation and environmental demands.

This increase is due to significantly higher irrigation demand than was forecast during the planning of the environmental flow. Extremely dry and warmer weather conditions through June and July have resulted in customer's water needs increasing significantly over a short period of time.

If you are normally affected by rising Murrumbidgee River levels, you may need to check your pumps or infrastructure.

A revised table of river heights is available.

For more information, or to receive direct emails or SMS, contact murrumbidgee.ewater@environment.nsw.gov.au

When will it happen?

The water delivery is scheduled to commence on Monday 24 July 2017. Expected travel times and river levels for Gundagai, Wagga and downstream locations are shown in Table 1 below.

River users will be notified (via email and SMS) once the commencement of water delivery has been confirmed.

If this water delivery event is cancelled, stakeholders will also be notified as soon as this decision is made.

If heavy rainfall is predicted after the planned release of environmental water, the event may be postponed or immediately ceased to minimise the chances of exceeding the target river levels.

How much water will be released and for how long?

The planned total volume is up to 200 gigalitres (GL). The total duration of dam releases for the event is expected to be 17 days.

The volume released will depend on allocation levels for 2017-18 water year and operational conditions. The peak flow is planned to be 5 to 6 days in the upstream river reaches, increasing to 12 days further downstream. See Table 1 for details.

The flow release will be gradual to minimise river bank erosion.

What river level is the flow expected to reach?

The environmental water releases are targeted to reach a river level of 3.7 metres (or 20,000 megalitres per day) at Wagga Wagga. This is below the flood level of 7.3 metres and the peak irrigation season water levels of summer 2013.

Will it affect me?

If you have land or infrastructure (including pumps) you could be affected by rising Murrumbidgee River levels. See Table 1 for predicted river heights at specific gauge locations.

If you think you may be affected by this proposed flow event please contact us as soon as possible by emailing murrumbidgee.ewater@environment.nsw.gov.au

Office of Environment and Heritage (OEH) has consulted with neighbouring landholders to identify and address potential effects of these flows. Landholders who lease areas of their floodplain property should forward this information on to lessees.

OEH and partner agencies will continue to work with landholders to address their concerns about the effects of river flows.

How will I be notifed if this planned flow is occurring?

OEH staff will manage the pre-event communications and WaterNSW will take over during the water release phase. Communication will continue for the duration of the release through regular event updates by local media and email.

Together we will provide regular communication updates to:

  • Landholders/managers – landholders or stakeholders who wish to be kept informed of the planning and delivery of this environmental water should contact us as soon as possible by email: murrumbidgee.ewater@environment.nsw.gov.au
  • Local councils – to ensure roads or drainage systems are being monitored.
  • Project partners – to ensure all partners are aware of the details of the proposed event and that potential risks are identified and managed within a risk management strategy.
  • SES – will be notified by OEH prior to any releases as a courtesy and preventative measure.
  • Public information – OEH updates will be issued to local newspapers and radio stations to inform the wider Murrumbidgee community of the environmental water release and the objectives of the flow. Event updates will also be posted on this news page.

Where do I get more information?

If you would like to be informed via SMS or email on progress of planning and implementation of the proposed Murrumbidgee wetlands connection flow then please send an email to: murrumbidgee.ewater@environment.nsw.gov.au

Table 1. Predicted river heights for proposed 2017 Murrumbidgee River Fresh event

Location

Height (m)

Discharge (ML)

Peak Duration (days)

Travel time from Burrinjuck

Gundagai 4.21 22,600 5-6 1.5 days
Wagga 4.02 22,000 5-6 2 days
Narrandera 5.0 19,000 5-6 5 days
Yanco Creek Offtake 3.2 to 3.5 1,500 to 1,8003 6-7 6 days
Yanco Creek at Morundah 2.1 to 2.2 900 to 1,000 6-7 7 days
Colombo Creek at Morundah 1.7 to 1.9 600 to 700 6-7 7 days
Darlington Point 4.2 to 4.5 14,400 to 16,400 6-7 7 days
Carrathool 4.2 to 4.5 12,000 to 13,400 7-8 10 days
Downstream of Hay Weir 5.0 to 5.3 11,500 to 12,700 8-9 12 days
Downstream of Maude Weir 4.8 to 5.1 10,200 to 11,200 9-10 13 days
Downstream of Redbank Weir 5.3 to 5.6 8,190 to 9,070 9-10 15 days
Downstream of Balranald Weir 5.1 to 5.4 6,630 to 7,560 10-12 18 days

1 similar to maximum irrigation flow levels in full allocation years
2 lower than any previous environmental flow event
3 the current DPI Water approval specifies environmental flow levels up to 2,600ML/day at the Yanco Creek Offtake (YCO), however with the proposed low target level at Wagga, the predicted peak YCO flow is unlikely to exceed 1,600ML/day.

Note: The actual river heights and flow durations may vary slightly from the above estimates as a result of 'other river operations' which are not related to the delivery of this environmental water event - these may include base irrigation demand and weir pool levels.

Who is responsible for the event?

OEH manages and plans environmental water allocations in NSW and is the lead agency for planning this environmental flow event. Water NSW manages water orders, deliveries and operates the river for all water users.

Partnering agencies include WaterNSW, Department pf Primary Industries, Riverina Local Land Services (RLLS) and the Commonwealth Environmental Water Office (CEWO).

Whose water is it?

Water allocation is being made available by the Commonwealth Environmental Water Holder and from NSW environmental water allowances.

Why is it being done?

To improve the health of wetlands along the mid-Murrumbidgee river.

When connected to the river these wetlands provide critical breeding and foraging habitat for native fish, waterbirds, frogs and other animals. They support native wetland plants which help to improve water quality and help to produce microscopic animals (zooplankton), insects and crustaceans which are important food for young fish. This water delivery will also help to move nutrients and carbon back into the river during winter when the water is cooler, supporting the river food web.

During the drought years (2002-10), hundreds of wetlands along the Murrumbidgee River that normally connect to the river remained dry. These wetlands suffered and are in need of more regular inundation to help them recover.

Most of these wetlands connected during Spring 2016 floods but have since dried out or water levels have dropped to low levels.

Monitoring of these sites indicate that many contain native fish including golden perch as well as young long- and short-necked turtles. This flow will help to reconnect these wetlands, improve their vegetation characteristics and will allow for native fauna and fish movement back into the river.

River ‘fresh’ to help native fish

Native fish will be the target of managed environmental flows in low-lying Murrumbidgee wetlands this winter. The flows will top up disconnected wetlands which support native fish. Increasing the volume of water in the wetlands will help keep native fish alive until future low-level connecting flows can be delivered at a better time for the fish to move from the wetlands to the main river channel.

For more information see our factsheet: Supporting native fish (PDF 1.4MB)

Restoring the Western Lakes: Wetlands return to Life

The Western Lakes near Balranald have been transformed thanks to the hard work and determination of local landholders and government.

Isolated from the Murrumbidgee River for more than a century, these inland lakes are now a haven for waterbirds.

This case study demonstrates the value of environmental water in restoring local wetlands and protecting both the natural and cultural heritage of the region.

The results are inspiring . . .

Working together to support native fish - August 2016

There was a time you could throw a line into the Murrumbidgee River and be almost guaranteed of catching a native fish.

These days, the effects of river regulation, in combination with other pressures that impact native fish, mean that anglers have to be a little more patient.

But what if that wasn't the case? What if there was something we could do to increase native fish numbers and improve the health of the river at the same time?

Well there is.

Work is underway to restore the habitat of native fish to provide adequate food, shelter, spawning cues and connectivity across the Murrumbidgee floodplain. Water managers, fish experts and scientists are working to maximise the benefits of water managed specifically for environmental outcomes, including native fish.

And that work is paying dividends.

Man holding fish

James Dyer and holding a Golden perch

In the past few months, a population of Golden perch has been detected at wetlands near Hay during monitoring of a watering event managed by the NSW Office of Environment and Heritage (OEH). The finding provided evidence of the important role environmental water plays in creating ideal conditions for native fish to breed and grow in a variety of riverine and wetland habitats, and eventually repopulate the river.

Office of Environment and Heritage (OEH) Water Management Officer James Dyer said monitoring was an important part of any watering event.

'In this case, it gives us confidence that we are on the right track in providing pulsed flows that encourage spawning, healthy habitat that can feed the growing fish, and flows that allow these fish to return to the river from their wetland feeding grounds,' Mr Dyer said.

At sites where water is being managed for the first time, scientific monitoring provides a baseline of information about the species present.

Man in canoe

Staff inspect the lagoon from the water. Photo J Maguire, OEH

'Based on this information, we can develop management plans to protect and improve fish populations and conduct further monitoring to ensure these plans are achieving their objectives,' he said.

'A healthy river system must be able to provide for the lifetime of the fish - food year-round, shelter, and connectivity at key times to allow the fish to move in and out of the river to complete its lifecycle.

'Managing water to a particular site generally provides a range of outcomes. In the early stages, water supports habitat - healthy plants that provide food and shelter. As the wetland grows stronger and more robust, it supports a greater diversity and population of plants and animals, including insects and crustaceans. These in turn become a food source for higher order predators, including fish.

'Importantly, a healthy river system must be able to provide for the lifetime of the fish - food year-round, shelter, and connectivity at key times to allow the fish to move in and out of the river to complete its lifecycle,' he said.

Depending on the site, scientific research may be carried out by a university, a Commonwealth funded program, another state government agency such as DPI Fisheries, or a private contractor.

The end result is increased efficiency in the use of available water, optimum outcomes for a range of species, including fish, and a healthier, more productive river system with flow-on benefits for riverine communities.

'Research and monitoring is ongoing,' Mr Dyer said.

'While environmental water plays a significant role in supporting our iconic fish species, native fish still face significant barriers to movement which isolates populations and makes them more vulnerable to drought.

'It also prevents movement of adults to spawning sites capable of supporting the young fish as they move and mature.

'Using the best available scientific knowledge, we are taking important steps to restore the health of rivers and wetlands in the Murrumbidgee valley.

'In doing so, we are helping to ensure a robust and sustainable native fish population which has added benefits for anyone who likes to cast a line,' he said.

Murrumbidgee golden perch - July 2016

Young golden perch in the lower Murrumbidgee have a chance to move from their wetland feeding grounds back into the river with the help of high river flows.

Increased river levels in the valley are the result of translucent and unregulated tributary flows following recent wet weather across the region.

OEH Environmental water manager James Dyer said the higher flows had provided connectivity between the river and some creeks and wetlands in the region.

'This has given a recently discovered population of golden perch recruits near Hay an opportunity to move back into the river,' said.

'This is a great result for this species as it is understood they need to return to the river to complete their life cycle.

'Although high flows in winter do not trigger breeding events, these flows are likely to provide an important boost to productivity in the river.

'A healthy, productive river provides food and habitat for the lifetime of the fish and aids the survival of young native fish that were spawned the previous spring,' Mr Dyer said.

OEH will continue to monitor native fish populations in the area and their responses to varying flows within the floodplain river system.

Great news for golden perch in Murrumbidgee valley - June 2016

Golden perch are thriving in waterways west of Hay, thanks to targeted flows supporting fish habitat.

Creeks and wetlands between Hay and Balranald have been closely monitored to assess the role of targeted water deliveries to the area since the 2010 floods. And it's good news for Golden perch, or 'yellow belly'.

James Dyer from the Office of Environment and Heritage said evidence of fish recruitment was emerging.

'Our recent monitoring of environmental watering responses showed at least half the fish captured were Golden perch,' Mr Dyer said.

'They ranged in length from 10 to around 30 centimetres.

'The larger fish probably entered the system during floods in 2010 and 2012 but the smaller fish are likely to have resulted from targeted environmental flows in the years since,' he said.

Pulses of water - or 'freshes' - running through the river are known to trigger breeding of Golden perch. These flows can also help to carry the eggs and larvae along the river or creek. Higher flows can also carry drifting eggs and larvae out onto the productive floodplain wetlands. These juvenile fish later return to the river as a new generation of young fish.

'NSW and Commonwealth planned water deliveries appear to have carried Golden perch eggs and larvae into floodplain wetlands and creeks where they have developed,' Mr Dyer said.

'But providing this water isn't just about transport.

'Water deliveries over the last 10 years have boosted the health of the wetlands themselves.

'Aquatic plants, plankton and insects are more abundant, all of which provide a source of food for native fish.

'So not only have the Golden perch been able to breed, but water for the floodplain environment has provided a healthy habitat to sustain and nourish their young,' he said.

Golden perch may travel thousands of kilometres throughout the Murray-Darling river system either as drifting larvae or as actively swimming juveniles and adults.

The young Golden perch recorded in these wetlands may one day colonise other rivers and floodplains connected to the Murrumbidgee.

'Our next objective is to help these fish find their way out of the local wetlands and back into the river using follow-up environmental watering events,' Mr Dyer said.

'The detection of these fish demonstrates a great outcome which allows us to now focus our efforts on supporting healthy habitat for these important native fish.

'It also provides a good example which we can try to replicate again and again by smart use of environmental flows,' he said.

Dr Katherine Cheshire from DPI Fisheries said fish played a critical role in the whole river system and were the basis of a billion dollar recreational fishing industry.

'Fish help to cycle nutrients within the river system and provide food for other parts of the food web including waterbirds,' Dr Cheshire said.

'Looking after fish with environmental water provides a range of environmental, social and economic benefits, including better fishing for target species like yellow belly.

'We know that restoring fish populations through environmental water delivery and via the protection of natural flows can be an effective way to manage river health.

'The success of environmental watering in the Murrumbidgee is a credit to the collaborative effort of scientists, environmental water managers and environmental water holders in both the state and the Commonwealth,' she said.

Commonwealth Environmental Water Holder David Papps said this event was just a hint of what was possible when governments, scientists and communities work together.

'The environmental water supplemented irrigation and domestic water that was in transit at the time, allowing us to create the conditions needed to encourage fish movement, spawning and recruitment,' Mr Papps said.

'Complementary monitoring undertaken by Commonwealth and State governments has recorded good young of year recruits of large bodied native fish including Murray cod and Golden perch in creek, lake and wetlands systems in the lower Murrumbidgee.

'This is not only good news for the fish communities, it's great news for anglers, particularly if we can encourage these fish to return to the main river channel in the future,' he said.

James Dyer OEH

James Dyer OEH

Waterbirds flock to Griffith wetlands – March 2016

Mud, glorious mud! It's is proving a major drawcard for travelling waterbirds at wetlands near Griffith, NSW.

Some waterbirds have flown thousands of kilometres to forage on the mudflats of Campbell's Swamp, north-east of Griffith, while others have emerged from nearby wetlands to enjoy the times of plenty.

Thanks to environmental water, the site is providing ideal habitat for a long list of waterbirds that are feeding on the mudflats and/or breeding in the rushes.

Australasian bitterns, little bitterns black-winged stilts, glossy ibis, freckled ducks, plumed whistling ducks and magpie geese have all been spotted at the swamp.

The NSW Office of Environment and Heritage has managed the delivery of 400 megalitres of environmental water to the site in recent months.

Senior environmental water manager James Maguire said the swamp was part of a mosaic of wetlands scattered across the region.

'Campbell's Swamp is an important part of a much bigger system,' Mr Maguire said.

'Some wetlands favour certain birds because of their proximity to rivers or their plant communities.

'Some areas become waterbird hotspots when other wetlands in the region dry out.

'Campbell's Swamp is ideal for wading waterbirds because of its shallow waters, mudflats, reeds and rushes.

'The shallow water and mudflats are ideal for foraging while the reeds and rushes provide shelter and harbour insects and frogs which provide another source of food for the waterbirds,' he said.

Endangered Australasian bitterns have also been detected at the site.

'This site, and others like it, provide year-round habitat for a range of waterbirds and native plants,' Mr Maguire said.

'Australasian bitterns are known to be breeding in Campbell's Swamp and nearby rice fields.

'While rice paddies provide temporary habitat, wetlands like Campbell's Swamp support a greater diversity of plants and animals and provide habitat for the lifetime of the bittern.

'Wetlands like this are also safe sanctuary for birds that have bred elsewhere and need a home after other sites have dried,' he said.

A number of threatened birds have been detected at sites in the Murrumbidgee valley including the Fivebough and Tuckerbil swamps near Leeton and Nericon Swamp, also near Griffith.

 

Campbell

Campbell's Swamp. Photo J Dyer OEH

 

Haven for wildlife in Murrumbidgee valley, February 2016

A shallow lagoon has been transformed into a miniature oasis thanks to environmental water and the efforts of local land and water managers.

Staff from the NSW Office of Environment and Heritage (OEH) have discovered a hidden treasure-trove of native plants and animals at Gooragool Lagoon, near Darlington Point.

Three species of native lily have been found along with up to 300 waterbirds nests, with chicks at various stages of maturity.

Senior Environmental Water Manager James Maguire said the discovery was testament to the co-operative efforts of nearby land managers and OEH staff.

'We've been working closely with the management of nearby Kooba Station to achieve the best possible outcome for all involved,' Mr Maguire said.

'Kooba Station has used the lagoon as an off-river storage for irrigation.

'After coming to an agreed outcome in spring, water which was pumped in by Kooba Station was retained in the lagoon, while provisions were made to enable Kooba Station to continue with their irrigation directly from the river.

'As the lagoon began to evaporate, an additional 1145 megalitres of NSW OEH Environmental Water Allowance (EWA) was supplied through Murrumbidgee Irrigation channels to top up the site.

'This allowed the waterbirds to successfully raise their chicks while native plants established, flowered and set seed,' he said.

Swamp lilies, wavy marshwort and water primrose were found in abundance in the shallow lagoon backwaters.

'In the deeper water, up to 300 cormorant and darter nests containing eggs, fluffy chicks and newly fledged young were found in the trees,' he said.

Mr Maguire said the timing of the extra environmental flow was just one of the factors contributing to the success of this event.

'Thanks to the support of Kooba Station we are seeing tremendous benefits to flora and fauna,' he said.

'With the water OEH transferred to them, Kooba Station have been able to irrigate directly from the river this season, which removed the need for the lagoon to be used as a storage.

'Meanwhile, water levels in the lagoon have been maintained for the best possible ecological outcomes.

'It's an arrangement I would like to see repeated because it benefits both the environment and the landholder.

'It means less pumping for landholders and one of the largest lagoons on the Murrumbidgee River is returned to a more natural state,' Mr Maguire said.

Three species of native water lily have been found at Gooragool Lagoon. Photo J Maguire OEH

Three species of native water lily have been found at Gooragool Lagoon. Photo J Maguire OEH

Frogs bounce back after enviro-water, February 2016

Tall spike rush has re-established at Yarradda Lagoon

Tall spike rush has re-established at Yarradda Lagoon

Endangered southern bell frogs have been found for the first time in 40 years at Yarradda Lagoon in the Riverina.

The discovery was made during monitoring of environmental watering, late last month.

Several adult southern bell frogs were heard calling while a number of young frogs and distinctive golden tadpoles were found.

It's a promising sign for the lagoon which was hard hit by the millennium drought.

The NSW Office of Environment and Heritage has been working to restore the health of the lagoon by managing the delivery of environmental water to the site.

Senior Environmental Water Manager James Maguire said successive flows in 2014 and 2015 had contributed to a steady improvement.

'The wetland plants are re-establishing and the variety of species being recorded has increased,' Mr Maguire said.

'This year we have seen the return of tall spike rush and two species of water lilies which had been absent from the lagoon since the millennium 2001.

'It's growing alongside red milfoil, overlooked by river red gums - an encouraging response to our joint rehabilitation efforts here.

'Darters and cormorants have also been nesting in their hundreds in trees within the lagoon.

'The discovery of southern bell frogs is an added bonus and tells us that Yarradda Lagoon is beginning to support a more diverse ecosystem,' Mr Maguire said.

Yarradda Lagoon, which is part of the Murrumbidgee Valley National Park, is listed on the Directory of Important Wetlands (DIWA) because of its significance in providing habitat for colonial nesting birds and migratory bird species.

At just under three metres deep, the lagoon often retains water during dry periods making it a sanctuary for native fish, frogs and a range of plant and animal species.

The lagoon is the subject of Long Term Intervention Monitoring involving staff from Charles Sturt University, funded by the Commonwealth Environmental Water Office.

Neighbouring landholders have taken on the job of pumping water into the site in collaboration with Office of Environment and Heritage. Without their assistance, the lagoon would have remained dry like hundreds of others along the river.

Staff inspect the lagoon from the water. Photo J Maguire OEH

Staff inspect the lagoon from the water. Photo J Maguire OEH

Young southern bell frog at Yarradda Lagoon. Photo C Amos OEH

Young southern bell frog at Yarradda Lagoon. Photo C Amos OEH

Darter chicks huddle in their nest at Yarradda Lagoon. Photo J Maguire OEH

Darter chicks huddle in their nest at Yarradda Lagoon. Photo J Maguire OEH

Darters on their nests at Yarradda Lagoon. Photo J Maguire OEH

Darters on their nests at Yarradda Lagoon. Photo J Maguire OEH

Murrumbidgee Piggyback Flow 2015 - Update 25/09/15

Planned Murrumbidgee Piggyback Flow Will Not Proceed in 2015

The planned Murrumbidgee Piggyback flow targeting Murrumbidgee and Yanco Creek system wetlands will not go ahead in 2015.  Landholder concerns raised with the NSW Office of Environment and Heritage (OEH) in late August remain unresolved and alternate plans are being made with water allocations.

 

Recent increases in dam releases relate to rising irrigation demand and are not environmental flows.

OEH and partners agencies are considering a range of flows for the Yanco Creek system.  Yanco Creek system stakeholders can expect notifications of upcoming flow heights and duration when plans are finalised.

 

If you wish to receive updates about future environmental flows in the Murrumbidgee Valley via email please register with:

Environment Line 131 555 or
info@environment.nsw.gov.au

 

Flows Boost Mid-Murrumbidgee Wetlands Below Darlington Point - 3/09/15

Rain in the Murrumbidgee catchment has provided the trigger to direct long-awaited flows into the nationally significant Mid-Murrumbidgee wetlands.

Natural high river flows have been topped up with up to 1,800 megalitres per day of environmental water released from Tom Bullen storage, just upstream of Darlington Point.

Water flows in the Murrumbidgee reached 14,000 megalitres per day at Darlington Point, a height of 4.14 metres, filling some low lying lagoons, billabongs and creeks which have not had water since 2012.

James Dyer, OEH Murrumbidgee Environmental Water Manager visited some of the Mid-Murrumbidgee wetlands and is pleased with the results.

'This allocation of environmental water has extended the peak of the natural high flow in the river, allowing wetlands more time to fill,' Mr Dyer said.

'This flow will also provide an injection of nutrients into the river which will boost productivity and provide benefits for native fish'.

The Mid-Murrumbidgee wetlands support a wide range of native plant species, help improve water quality, and feed the river with insects and crustaceans, juvenile fish, nutrients and carbon, supporting its productivity.

Murrumbidgee River ‘piggyback’ flow 2015 - Background Information

The Office of Environment and Heritage (OEH) has been working with partner water management agencies and landholders planning a 'piggyback' environmental water release in the Murrumbidgee River. Planned after a rainfall event sometime in late winter to early spring 2015, its purpose is to reach numerous low lying billabongs, creeks and lagoons in the Murrumbidgee and Yanco Creek wetland systems.

The event was also planned in 2014 however, weather conditions were unsuitable for this event last year. OEH and partners are now planning for the event to occur in 2015.

What is the 'piggyback' flow?

A 'piggyback' flow is the release of environmental water on top of existing natural river flows. Water will be released into the Murrumbidgee River from the two major water storages, Burrinjuck and Blowering Dams, to allow water to reach low-lying wetlands that occur along the river and the Yanco Creek system.

Releases would be made when there are significant unregulated inflows from tributary streams, downstream of the major water storages. By 'piggybacking' onto these natural inflows, the storage release requirements can be reduced and this can make the limited environmental water allocation last longer and create a more effective watering event.

If necessary, additional minor piggyback releases may potentially be made from the Tombullen off-river Storage (near Darlington Point).

What level will the flow reach?

The environmental water releases are targeted to reach a river level of 4.9 metres (or 27,500 ML/d) at Wagga Wagga. The predicted river heights for the release are shown at Table 1. This is well below the minor flood level of 7.3 metres and one metre lower than previous environmental water release levels in 2011.

By setting the target of 4.9 metres, it is hoped that inconvenience to stakeholders is minimised. However, the possibility of exceeding or falling short of this target due to unforeseen circumstances, such as heavy local rainfall, needs to be recognised.

If heavy rainfall is predicted during or shortly after the planned release of environmental water, the event will be managed accordingly, postponed or immediately ceased, to achieve river levels of 4.9 metres at Wagga.

Table 1. Predicted river heights for proposed Murrumbidgee Piggyback event.

Location

Height (m)

Discharge (ML)

Duration

(days)

Travel time from Burrinjuck

Gundagai

4.0 to 4.41

20,900 to 24,800

3-4

1.5 days

Wagga

Up to 4.92

Up to 27,500

3-4

2 days

Narrandera

5.0 to 5.4

21,500 to 25,200

4-5

5 days

Yanco Creek Offtake

3.4 to 3.83

1,700 to 2,200

4-5

6 days

Darlington Point

4.4 to 5.0

16,100 to 20,900

5-6

7 days

Carrathool

4.5 to 5.0

13,300 to 15,800

5-6

10 days

D/S Hay Weir

5.0 to 5.5

12,000 to 14,000

6-7

12 days

D/S Maude Weir

5.0 to 5.6

11,000 to 13,000

8-9

13 days

D/S Redbank Weir

5.7 to 5.9

9,280 to 10,100

10-12

15 days

D/S Balranald Weir

5.3 to 5.8

7,900 to 9,700

12-14

18 days

1 similar to max irrigation flow levels in full allocation years

2 lower than any previous piggyback flow event

3 the current DPI Water approval specifies environmental flow levels up to 2,600ML/day at the Yanco Creek Offtake (YCO), however with the proposed target level at Wagga, the predicted peak YCO flow is unlikely to exceed 2,200ML/day.

Note: The actual river heights and flow durations may vary substantially from the above estimates, depending on teh extent of supplementary orders.

How much environmental water will be released?

The volume of environmental water released over the duration of the event could range from 40,000 megalitres (ML) up to a maximum of 260,000 ML, depending on allocation availability and the size of the base flow. Water will primarily come from NSW environmental water allowances and also from Commonwealth environmental water holdings.

Why is it being done?

During the drought years (2002-2010), hundreds of wetlands along the Murrumbidgee River that connect to the river during high river flows remained dry. The lack of return flows to these wetlands has resulted in severe impacts on their aquatic vegetation and ecology. The planned environmental water releases will be designed to inundate a large number of the lower lying wetlands and greatly assist in their recovery.

Well-functioning wetlands provide critical breeding and foraging habitat for native fish, waterbirds, and frogs. They support a wide range of native plant species, help in improving water quality, and feed the river with insects and crustaceans, juvenile fish, nutrients and carbon – supporting its productivity.

When will it happen?

Currently maintenance works at Burrinjuck Dam are tmporarily constraining release capacity. The decision to release environmental water is dependent on enough rainfall to initiate tributary flows that will reach a minimum river level of approximately 3.5 metres at Wagga. By mid-late September with increasing water available and Burrinjuck Dam fully operational again, a release may be possible on a lower base flow. Environmental water releases would still piggyback on these flows to target a combined river level of up to 4.9 metres at Wagga.

The environmental water releases are being planned for some time between August and October 2015. The actual commencement date and duration for the event will be dependent on rainfall and environmental water availability. The Bureau of Meteorology (BOM) rainfall forecasts and Water NSW operational limitations indicate that the likely timing for an event currently (as of 17 August 2015) is:

17–23 August - no 'piggyback' flow releases planned; no significant rainfall forecast until the 21 August.

24–31 August 'likely' due to the wet catchment conditions and a favourable rainfall forecast, subject to status of the Burrinjuck maintenance work.

September 1–15– 'very likely' assuming completion of maintenance works at Burrinjuck Dam and increased environmental water available on account.

September 16–30– 'most likely' assuming maintenance works are completed and a further increase in environmental water is available to allow larger releases to be made on a lower base flow.

October 1–15 – 'unlikely'. Generally a higher irrigation demand at this time of year means a very significant rainfall event is required.

October 16–31 – 'Highly unlikely'. Typically, peak irrigation demand and a drying catchment means a very significant rainfall event is required to provide sufficient runoff to trigger the event, while also temporarily reducing irrigation demand.

The above event timing indications will be reviewed by OEH and provided to stakeholders on our contact list on a weekly basis. When a potentially suitable rainfall event is forecast daily updates will be provided to stakeholders.

Stakeholders will be notified once a commencement window has been confirmed and prior to releases of environmental water.

If environmental releases are not required, or if the piggyback flow is abandoned, stakeholders will be notified as soon as this decision is made.

Will it impact me?

If you have property that is normally affected by rising Murrumbidgee River levels, there is a possibility that you could be affected by the 'piggyback' flow. As the proposed release is well below the minor flood level, impacts are expected to be minimal.

OEH has consulted with many potentially affected landholders with a view to identifying risks that may be associated with this environmental flow and to inform the development of strategies to deal with these risks should they arise.

If you think you may be impacted by the proposed 'piggyback' flow please contact OEH via avenues listed below.

Who is responsible for the event?

OEH manages environmental water allocations in NSW and is the lead agency for the environmental flow event. State Water manages water orders and deliveries.

Partnering agencies include State Water, DPI Water, Riverina Local Lands Services and the Commonwealth Environmental Water Office.

How will I know if the flow is occurring?

Stakeholders who wish to be kept informed of the planning and implementation of the Murrumbidgee 'Piggyback' Flow should provide their email and/ or mobile contact details via the NSW Environment Line (details at the bottom of the page).

Landholders/managers - who may be impacted by rising river levels will be contacted and notified through either face-to-face meetings, telephone, SMS messages or email.

Communication will continue for the duration of the event through the provision of regular event updates to website, local media and our stakeholder contact lists.

OEH staff will manage the pre-event communications and State Water will be involved in the release phase; together they will provide regular communication updates to:

Local councils – contact with the relevant councils will be made to ensure infrastructure such as roads or drainage systems are not unexpectedly inundated by released environmental water.

Project partners – to ensure project partners are aware of the details of the proposed event and that potential risks are identified and managed within a risk management strategy.

SES – will be notified by OEH prior to any releases as a courtesy and preventative measure. However, as the proposed flow (4.9 metres) is below the minor flood level (7.3 metres) at Wagga, it is not anticipated that the SES will be involved in flow-related operations.

General public – OEH media releases will be issued to local newspapers and radio stations to inform the wider Murrumbidgee community of the environmental water release and the objectives of the flow. Regular event updates will be posted on this web page.

Where do I get more information?

This website will be updated with latest information on the 'Piggyback' Flow for 2015.

For further information or to recieve direct updates via email, please register on our stakeholder contact list via:

info@environment.nsw.gov.au or

Environment Line: 131 555

Feathered frenzy at Fivebough and Tuckerbil

Birds have flocked to the Fivebough and Tuckerbil swamps (pictured) after environmental watering. Photo: J Maguire OEH

Birds have flocked to the Fivebough and Tuckerbil swamps (pictured) after environmental watering. Photo J Maguire OEH

Thousands of birds have converged on the Fivebough and Tuckerbil swamps near Leeton, in south west NSW, for what could become the biggest waterbird gathering on the site in 20 years.

Brolgas, bitterns and terns have been spotted after environmental watering provided the perfect conditions for feeding, foraging and - in some cases - breeding.

The Office of Environment and Heritage (OEH) has allocated more than 600 megalitres of environmental water to the Ramsar-listed wetlands.

At dusk and dawn, thousands of birds can be seen in the skies above the swamps - a spectacle that is expected to continue into the New Year.

To learn more, see our media release.

Research underway in the North Redbank wetland system

Return flows are the subject of research being conducted in the North Redbank wetland system. Photo: James Maguire/OEH

Return flows are the subject of research being conducted in the North Redbank wetland system. Photo James Maguire OEH

In the North Redbank wetland system, scientists have joined forces with water managers to better understand the benefits of environmental flows as they pass through the wetlands and return to the Murrumbidgee River.

The Office of Environment and Heritage (OEH) is managing the delivery of environmental flows to the North Redbank wetlands near Balranald with a series of ‘return flows' to follow.

Monitoring is being conducted by OEH staff alongside scientists from Charles Sturt University (CSU) who are funded by the Commonwealth Environmental Water Office (CEWO).

Senior Environmental Water Manager James Maguire said the project was designed to replicate the natural connectivity between the river and floodplain.

'We're looking at the potential benefits of returning this highly productive water to the main Murrumbidgee River channel,' Mr Maguire said.

'Water from the warm, shallow swamps is brimming with zooplankton, fish larvae and macro invertebrates.

'When it's returned to the river system it becomes part of the food web, feeding bacteria, fish, yabbies and other river animals.

'By monitoring these return flows, we hope to inform the management of future watering events,' he said.

Return flows from the North Redbank swamps will be pulsed several times over the course of a month for several months.

'Scientists from CSU will work alongside OEH staff to monitor the flows and their effects,' Mr Maguire said.

'The results will help to determine timing, duration and future management of return flows.

'In the long term, the results will guide planned investment in new infrastructure such as fish-friendly water regulators that allow native fish passage.'

Dr Skye Wassens from CSU is co-ordinating the team of scientists monitoring the event.

Dr Wassens' work is part of a collaborative effort to share the knowledge and expertise of individuals and organisations with an interest in environmental water across the Murray Darling Basin.

'The CSU team hopes to apply the lessons learned from the North Redbank return flows to other lower Murrumbidgee floodplain events,' Dr Wassens said.

'The monitoring is aimed at determining the scope of the effect we can achieve and the types of outcomes we can expect.

'Planning for return flows is determined by the ecological outcomes we hope to achieve.

'If, for example, our goal is to allow fish spawned on the floodplain to return to the river, then our monitoring results may enable us to plan for that.

'The effects could vary greatly depending on the timing of the return flows.

'For example, we may be able to target a nutrient peak in the river to coincide with the presence of larval cod.

'By starting these return flow pulses in spring, while the weather is still quite cool, we expect to reduce the nutrient load and minimise the risk of later hypoxic black-water occurrences.'

The results of the study will be used by the OEH and other relevant authorities to determine environmental water management goals and the best methods for achieving their objectives.

The North Redbank wetlands have been the recipient of environmental water over a number of years.

This year, the OEH has allocated 25,000 megalitres of Environmental Water Allowance (EWA) to the project with a further 20,000 megalitres from the CEWO.

This year, with the watering occurring earlier than last, the OEH is also hoping to trigger a significant waterbird breeding event in an historical rookery site within the wetland system.

Paika Lake filled for the first time in a century

Paika Lake at sunset

Paika Lake is a 450 hectare intermittent lake located 20 kilometres north of Balranald. Paika Lake had been isolated from the rest of the Murrumbidgee floodplain in the early 1900s and hadn’t received water for over a hundred years. This video looks at the results of environmental water on the Lake and the associated wetlands in Narwie and Dundomallee.

The Murrumbidgee river is one of Australia’s most regulated river systems, which poses some unique challenges and opportunities for the management of environment flows in the catchment.

Covering an area of 81,527 square kilometres, the catchment includes 26 storage or diversion structures, along with a 1690-kilometre stretch of the river, and surrounding wetlands.

Lowbidgee Wetlands videos

Watch ABC TV News videos:

Birds from rejuvenated wetlands take flight (December 2010)
Water release revives Lowbidgee wetlands (September 2010)

April 2010

The Lowbidgee Wetlands near Balranald come to life after 8,200 megalitres of NSW and Commonwealth environmental water was released via the North Redbank channel in March and April.

Birds flocked and vegetation flourished as the water spread across the floodplain on seven private properties: 'Murrundi', 'Springbank', 'Glen Avon', 'Auley', 'Moola', 'Riverleigh' and 'Baupie'. View video transcript (DOC 34KB)

Largest environmental flow floods Yanga National Park

The wetlands and creeks of Yanga National Park continue to be a focus for environmental watering by the NSW and Commonwealth governments.

The NSW Office of Environment and Heritage manages the delivery of environmental water to various lakes and wetlands within Yanga National Park and the surrounding region.

Watch this space for updates on local environmental watering events.

Red gums in the Yanga National Park

Red gums in the Yanga National Park

Mist over Piggery Lake, Yanga National Park. Photo: J Maguire/OEH

Mist over Piggery Lake, Yanga National Park. Photo J Maguire OEH

Water flows to Tala Lake. Photo: James Maguire/OEH

Water flows to Tala Lake. Photo James Maguire OEH

Tala Lake at sunset. Photo: James Maguire/OEH

Tala Lake at sunset. Photo James Maguire OEH

Find out more about Yanga National Park.

 

 

Lowbidgee floodplain

The lower Murrumbidgee floodplain (Lowbidgee) covers approximately 300,000 hectares and is listed in the Directory of Important Wetlands of Australia. It has supported some of the largest waterbird breeding colonies in Australia and is home to the State’s largest known population of the endangered southern bell frog and approximately 22,000 hectares of river red gum forest and woodland (part of the largest continuous forest of this type outside the Murray Valley). Lowbidgee floodplain wetlands have been affected by irrigation development, flow regulation and floodplain agricultural development over a number of decades.

RERP action

Increasing the environment’s share of available water

At the end of May 2011, RERP had purchased 26,546 megalitres (ML) of general security, 5,679 ML of supplementary access water and 665 ML of unregulated water entitlements. Combined with the Australian Government’s Environmental Water Holdings a total of 103 ML of high security, 97,888 ML of general security, 26,499 ML of supplementary access and 665 ML of unregulated water entitlement is available to the environment, in addition to environmental water available under the Murrumbidgee Water Sharing Plan.

Protecting and conserving wetlands on private land

Management agreements have been negotiated with landholders on three private properties in the area: Dundomallee, Nap Nap Station and Talpee. These agreements, covering 650 hectares, are benefiting wetlands on these properties through the fencing of wetlands to improve grazing management, revegetation activities in wetland areas and minor earthworks to improve environmental water delivery.

Yanco Creek projects

Mollys Lagoon Regulator immediately following construction. Photo: Janaka Weeraratne State Water

Mollys Lagoon Regulator immediately following construction. Photo: Janaka Weeraratne State Water

River regulation and other factors have affected the health of river red gums and caused a decline in aquatic species within parts of the Yanco Creek System. Regulating structures have been constructed at Mollys Lagoon/Dry Lake and Gum Hole/Possum Creek Complex along Yanco Creek that will allow for the reintroduction of a more appropriate drying and flooding regime and provide ecological benefits for these wetlands.

At a cost of $0.9 million, RERP has funded the installation of a fishway at Tarabar Weir (near Leeton). Yanco Creek has a range of native fish species typical of a lowland Murray-Darling stream including three threatened species (the Murray cod, trout cod and silver perch) and important populations of freshwater catfish and Murray crayfish which are in decline across much of the Murray-Darling Basin. The new Tarabar Weir fishway will allow the passage of these species to over 360 kilometres.

Yanga National Park works program

Yanga National Park covers approximately 69,000 hectares of the Lowbidgee floodplain and has some of Australia’s largest and most important waterbird breeding sites.

Flooding across the Lowbidgee Floodplain has been significantly reduced as a result of river regulation and floodplain development and consequently the area and condition of vegetation has declined. To improve water management, RERP funded a $1.6 million infrastructure program including the installation of 10 regulating structures, 10 flood-ways and the breaching of 40 pre-existing embankments. The new structures have restored the hydrologic function of the floodplain on Yanga and allow for the improved management of environmental water. Several environmental waterings have been undertaken using this new infrastructure to maintain wetland habitat and river red gum forest health, support populations of the threatened southern bell frog and maintain egret nesting sites. Management of wetlands on Yanga has been further enhanced through the installation of a gauging network (including six flow-metering stations, 17 height only sites, 11 piezometer sites and one weather station).

Fostering Aboriginal connection to wetlands

Twenty Aboriginal people participated in a RERP project to identify and record culturally significant sites across the Lowbidgee Floodplain to document the connection of Aboriginal communities to wetlands. Surveys were conducted on 13 properties and resulted in the identification of over 800 previously unrecorded Aboriginal archaeological sites, including burial sites, cooking mounds, hearths, modified (scarred) trees, mussel shell middens and areas where food, fibre and medicine plants were traditionally gathered. Follow-up conservation works have been undertaken where exposed Aboriginal burials were discovered. The oral histories of 10 Aboriginal people have also been recorded and 20 Aboriginal people have been trained in oral history recording and research skills or archaeological survey techniques to identify Aboriginal values across the wetland landscapes.

RERP has also helped facilitate a number of negotiations to allow improved access and use arrangements for Aboriginal people to culturally significant wetlands on private lands. To date, one formal access and use agreement has been signed which provides access for a local Aboriginal community to a culturally significant wetland, with negotiation on other agreements progressed.

Hydrodynamic and hydrological modelling tools

Great egrets, Yanga National Park wetland. Photo: Paul Childs OEH

Great egrets, Yanga National Park wetland. Photo Paul Childs OEH

A hydrodynamic model of how water moves through Yanga National Park has been completed which will assist water managers to determine the optimum volume and timing of water releases in support of key species. This information has been used in the development of a hydrology model for the Lower Murrumbidgee floodplain, that represents the effects on the wetland of changes to infrastructure, regulation practices, dam operation rules and climate change over the short term (years) and long term (hundreds of years).

Decision Support System

Development of a Decision Support System (DSS) for the Lower Murrumbidgee wetlands has been completed, bringing together relevant areas of scientific research, to support a transparent and scientifically rigorous decision-making process. The DSS integrates the Lowbidgee ecosystem response model with the hydrologic model, allowing for the comparison of scenarios relating the volume and timing of water delivery to ecological outcomes. As it develops, this tool will assist water managers optimise the use of environmental water and sustain the identified ecological values of the wetlands.

Baby boom follows environmental watering at Yanga National Park

A new generation of waterbirds will soon take flight from nesting sites at Yanga National Park, near Balranald.

Hundreds of egrets, night herons and cormorants have taken up residence in the park, establishing two rookeries where they have built their nests and are now raising their young.

Environmental water has created ideal conditions for the breeding event – a first for internationally recognised great egrets in the park since 2011.

The NSW Office of Environment and Heritage is managing the event which will see up to 73,000 megalitres of Commonwealth environmental water and 6000 megalitres of OEH water delivered to the site.

To read more about the baby boom in progress, see the full media release Baby boom in Yanga wetlands.

Nature close-up - take a tag-along tour of Yanga National Park

Yanga National Park is the place to be these school holidays with tours taking visitors into the far reaches of this dynamic ecosystem.

Visitors to Yanga National Park can join one of three tag-along tours hosted by the National Parks and Wildlife Service on Wednesday 8 April, Friday 10 April or Thursday 16 April.

These all-day tours begin at 9.30am with a cost of $20 per vehicle and take in areas of the park not normally accessible to the public.

Bookings can be made through the park office on (03) 5020 1764.

For more information read the full media release Wet, wild school holidays adventures at Yanga

Yarradda Lagoon on the road to recovery

Fish, frogs, turtles, trees and birds will all benefit from environmental watering at Yarradda Lagoon, near Darlington Point.

Work is underway to restore the health of the lagoon that was hit hard by the millennium drought.

Over the past few months, neighbouring landholders have managed the delivery of environmental water to the lagoon, in conjunction with the NSW Office of Environment and Heritage (OEH) and the Commonwealth Environmental Water Holder.

See the full media release Yarradda Lagoon Restoration a Collaborative Effort.

Understanding 'return flows'

The NSW Office of Environment and Heritage is managing a series of ‘return flows’ in the North Redbank wetlands system. The flows are being carried out in conjunction with the Commonwealth Environmental Water Holder and Charles Sturt University.

What is a return flow?

Water from wetlands and floodplains is rich in nutrients, zooplankton, fish larvae and micro-invertebrates. When this water makes its way from the wetland or floodplain back into the river channel it is known as a ‘return flow’.

Return flows have become less common as demand for water increases. By monitoring planned flows, water managers can learn more about the role they play in the health of the river for all water users.

Why are return flows important?

Return flows restore the natural connectivity between the floodplain and river. The nutrient-rich waters become part of the food web, feeding fish, yabbies and other river animals.

Why is research important?

By understanding the benefits of return flows, water managers can target specific objectives with the timing and duration of future environmental watering events.

Who is conducting the research?

Scientists from Charles Sturt University (CSU) are funded by the Commonwealth Environmental Water Office (CEWO) to monitor conditions and ecological responses.

Are there any risks involved?

To avoid any adverse impacts on the river, wetland water is assessed prior to and during release and modelling is undertaken to identify release volumes.

Findings to date

Levels of aquatic micro-invertebrates in the wetlands can be up to 10 times higher than the river. This makes the transfer of water important for feeding young native fish.

 

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Page last updated: 16 August 2017