Research underway in the North Redbank wetland system
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.
Return flows are the subject of research being conducted in the North Redbank wetland system. Photo: James Maguire/OEH
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.
Native fish set to benefit from Burrendong Dam's cold water curtain
Native fish will be among the beneficiaries of a new multi-million dollar cold water curtain at Burrendong Dam.
Members of the Environmental Flows Reference Group inspect the cold water curtain at Burrendong Dam. Photo: Tim Hosking/OEH
The flexible curtain has been constructed around the intake tower to allow warmer, oxygen-rich surface water to be released downstream.
And the benefits are expected to flow for the whole river system.
The NSW Office of Environment and Heritage (OEH), with advice from the Macquarie-Cudgegong Environmental Flows Reference Group (EFRG), has already made use of this warmer surface water.
A ‘piggyback flow’ of 5000 megalitres was delivered to the eastern marshes in early September. The flow supplemented recent rainfall as well as stock and domestic flows.
A second flow of 30,000 megalitres was scheduled to reach the Macquarie Marshes in mid-October.
Senior Wetland and Rivers Conservation Officer Tim Hosking said the new curtain and warmer water would enhance the effects of these environmental flows and provide benefits to recreational river users as well.
“Anyone who has gone for a swim downstream of the dam will tell you how cold the water can be in the middle of summer,” Mr Hosking said.
“Until now, water for irrigation, town use and the environment has been released from a fixed intake point towards the bottom of the dam. In spring and summer that water can be quite cold and low in dissolved oxygen compared with conditions that would naturally occur in the river.
“The effect on river plants and animals – native fish in particular – has been significant.
“Research has shown that colder water impedes fish growth and reduces the length of their breeding season.
“Native fish wait for warmer water to breed which now doesn’t occur until later in spring and summer. By then, the European Carp have already spawned and competition for food is fierce, as carp compete at the very bottom of the food web by destructively eating algae and vegetation.
“Cold water also reduces the productivity of riparian and aquatic vegetation which further contributes to the challenges experienced by native fish” he said.
Mr Hosking said the ecosystem response to the curtain may be muted in the first year or two, but the effects over the next three to five years should be significant.
“The whole ecosystem will benefit - from the macro-invertebrates to the yabbies, shrimp, platypuses, native fish, turtles and waterbirds,” Mr Hosking said.
The Burrendong Dam cold water curtain is now operational. Photo: Tim Hosking/OEH
“With the right conditions, we hope to see improvements for native fish in the river reach between Burrendong and Narromine.
“From a social perspective, river users will notice warmer water when they go for a swim and over time, they’ll start to see more native plants and animals present in the river.”
The OEH is just one of several stakeholders keeping a close eye on the effects of Burrendong Dam’s new cold water curtain; with ongoing research being conducted by a team from the University of Technology Sydney, and additional funding allocated from the Commonwealth for NSW Department of Primary Industries (Fisheries) to undertake a system-wide fish survey.
In the meantime, staff from the OEH are looking forward to seeing the first effects of the season’s environmental flows, enhanced by warmer water via Burrendong Dam’s cold water curtain.
- The cold water curtain has been constructed at a cost of $3.4 million.
- The flexible rubber curtain can be moved up and down with the level of the water behind the dam.
- The initial concept design was funded by NSW Rivers Environmental Restoration Program, a Commonwealth program.
- Further design and construction costs were shared equally between the NSW Government and State Water customers.
- The environmental water release is a collaborative effort guided by an Environmental Flow Reference Group (EFRG) :
- The EFRG meets several times per year to discuss environmental watering strategies, outcomes and planning.
- The Murray Darling Basin Authority has identified native fish outcomes as an annual priority in the Macquarie River under the Murray Darling Basin Plan.
- Environmental flows in the Macquarie are managed by NSW OEH with key assistance from the Commonwealth Environmental Water Office (CEWO), State Water Corporation and the EFRG.
Waterbirds return as the Gwydir Floods - touring photo exhibition
Visit this stunning waterbird photo exhibition as it travels around north-western NSW. The exhibition was created by OEH wetland staff to celebrate the large-scale colonial waterbird breeding event that took place in the Gwydir Wetlands over the summer of 2011-12. The exhibition is touring the following locations;
- April: Warialda
- May: Tamworth
- June: Gunnedah
- July: Baradine
- August: Mungindi
- September: Glen Innes
- October: Dorrigo
View the images on flickr
Watch this Prime7 news clip showing how natural flooding and the strategic delivery of environmental water coordinated OEH have helped water birds thrive after years of drought.
Paika Lake filled for the first time in a century
OEH and a small group of landholders have managed the delivery of environmental flows to Paika Lake, 20 km north of Balranald. The 450 hectare lake had been kept dry due to a series of levees constructed more than a hundred years ago. Find out how this partnership helped more than 20,000 waterbirds, including three threatened species make the lake home.
Run time: 12:13 minutes
Creek systems flourish after years without water
The Jimaringle, Cockran and Gwynnes Creek systems between Wakool and Deniliquin are reaping the benefits of environmental flows, with vegetation flourishing and water birds and frogs enjoying the improved conditions. Download factsheet (13586Enviroflows.pdf 1506kb).
OEH has worked closely with local landholders to bring life back to the ailing 130km creek system, that travels through approximately 30 landholder properties located between the Edward and Murray Rivers.
To support the long term health of the environment, OEH is boosting natural water flows to deliver environmental water to the creek system. The environmental water flows began at the end of August 2012 and will continue into spring.
Environmental water at Gwynnes Creek. Sascha Healy/OEH
The health of the creek system suffered over the long dry period experienced in the last decade; Gwynnes Creek in particular has not had any substantial water flows for 40 years. So being able to leverage off the good wet conditions experienced in the last two years is a significant benefit for the system.
Monitoring inspections over the last two years in the Jimaringle and Cockran creeks have identified more than 20 waterbird species foraging in the creeks including egrets, cormorants and wood ducks.
Several different frog species have also been observed including pobblebonk, marsh and peron’s tree frogs. The painted burrowing frog was heard calling only days after the Gwynnes Creek environmental flows commenced.
The fringing River Red Gums, Black Box and Lignum and wetland vegetation such as Spike Rush and Duckweed have also shown improvement from the wet conditions.”
Up to 6,000 megalitres of environmental water in total from the NSW and Commonwealth government has been made available for delivery using Murray Irrigation Limited infrastructure.
Restoring the Tuppal Creek
In this video landholders talk about how red river gums and local wildlife are bouncing back with the help of environmental water delivered by OEH in 2012.
Cockran, Jimaringle and Gwynnes Creek Systems
This video shows how local irrigation infrastructure and teamwork have delivered environmental water to sections of the Murray Valley for the first time in 40 years with great results for plants and animals.
Extra water helps fish in the Edward-Wakool river system
Dissolved oxygen levels are now being boosted in this popular fishing river system thanks to extra environmental water deliveries being coordinated by OEH.
Edward Escape - environmental water release into
Edward-Wakool river system. Emma Wilson/OEH
Recent rainfall and flooding throughout the catchment had caused extra organic material to be deposited into the river, resulting in a ‘blackwater’ effect and lowering dissolved oxygen levels to below 2 milligrams per litre. This may have been causing native fish such as the Murray cod and yellow belly to experience severe stress and possible death.
It is expected that by 30 June 2012, up to 60 gigalitres of environmental water will have been released into the Edward-Wakool river system, since environmental releases commenced in early April.
There are promising signs that the poor quality blackwater is being diluted and better quality habitat created for native fish and other aquatic fauna.The Edward River at Moulamein recently registered healthier oxygen levels of around 4 milligrams per litre and there have been very few reports of fish kills to NSW Fisheries and the Murray- Darling Basin Authority.
This initiative has been delivered in partnership with the Commonwealth, State Water Corporation, Murray CMA, Forests NSW, NPWS, NSW Office of Water, Fisheries NSW, the river operators and the local community. All the environmental water for this event was sourced from the Commonwealth Environmental Water Holder.
Watering the world's largest river red gum reserves
Celebrating World Wetlands Day 2 February and 2011 International Year of Forests
Run time: 3.13 minutes
View video transcript (ForestedWetlandsVideoTranscript.doc; 28 KB)
Lowbidgee Wetlands videos
Watch ABC TV News videos:
Birds from rejuvenated wetlands take flight (December 2010)
Water release revives Lowbidgee wetlands (September 2010)
The Lowbidgee Wetlands near Balranald come to life after 8200 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 (LowbidgeeWetlandsVideoTranscript.doc; 34 KB)
Largest environmental flow floods Yanga National Park
Red gums, Yanga NP. Photo: Paul Childs/OEH
Piggery Lake, Yanga NP. Photo: J Maguire/OEH
Water flows to Tala Lake. Photo: James Maguire/OEH
Tala Lake. Photo: James Maguire/OEH
Find out more about Yanga National Park and environmental watering events.
Page last updated: 13 November 2014