River Murray operations 18-25 January 2017

27 January 2017

Welcome to our summary report on River Murray operations for the week ending 25 January 2017.

You can find the full weekly report under the River Murray system section of our website.

Rainfall and inflows

During the week, a surface trough extended from Western Australia, through central South Australia, New South Wales and Victoria, with a deepening low pressure centre over central South Australia. Moderate to heavy falls were recorded across the agricultural districts and south-eastern area of South Australia, much of western Victoria and western New South Wales. As the low pressure centre tracked over south-eastern Australia, moderate to heavy falls were recorded in eastern and central New South Wales and Victoria. Very similar to last week, rainfall over the south-east triggered modest increases to stream flows along the upper tributaries before rates receded. For example, on the Mitta Mitta River, the flow at Hinnomunjie bridge increased from 600 to 1,200 ML/day and has now returned to 550 ML/day. On the Ovens River at Rocky Point, the flow increased from 900 to 1,600 ML/day over the weekend before decreasing to rates below 900 ML/day during the last couple of days.

The eight day forecast for the southern basin looks dry, see map 2 below, and temperatures over the major irrigation districts are forecast to be high. Temperatures at Deniliquin are forecast to rise from 32 degrees tomorrow up to 42 degrees on Monday 30 January.

Total in storage

MDBA total storage decreased by 94 GL, with the active storage currently 6,825 GL (79% capacity).

System operations

With rain falling across parts of the Murray in recent weeks, demands and losses along the system have been lower than planned for. This means that more water has been arriving at Lake Victoria than expected so that deliveries in February, including from tributary inter valley trade (IVT) and from Menindee lakes may be reduced.  Updates will be provided in coming weeks with flow rates across the system being adjusted in response to the observed and forecast weather and demands.

River Operations

  • Dartmouth Reservoir’s storage volume increased 4 GL this week to 2,951 GL (78% capacity). The release, measured at Colemans gauge, was raised over the weekend to 2,400 ML/day. This pulse of water was provided for by MDBA’s minimum release provisions for Dartmouth and is designed to mimic a small natural pulse that will provide water quality and ecosystem function benefits in the Mitta Mitta River downstream of Dartmouth Dam. Another pulse is forecast for the weekend starting 18 February and will be similar to the pulse just gone. More details will be provided closer to the time.

  • Storage volume at Hume Reservoir fell by 35 GL this week to 2,586 GL (87% capacity). The combined flow from releases and inflows from the Kiewa River, measured at Doctors Point, has averaged close to 12,330 ML/day throughout the week.

  • The pool level at Lake Mulwala has averaged 124.82 m AHD and is currently at 124.74 m AHD. As anticipated in last week’s report, Mulwala Canal diversions fell 800 ML/day this week to 5,100 ML/day in response to rain.

  • The current release from Yarrawonga is 8,000 ML/day, including about 1,000 ML/day of environmental water being provided for large bodied native fish and continued bird breeding in the Barmah-Millewa forest and sites further downstream. The target flow of 8,000 ML/day is expected to continue in February.

  • These releases are lower than experienced over the last few years at this time of year due to downstream demands being supplemented by water from the Goulburn, Campaspe, Murrumbidgee and Menindee Lakes. This allows more water to be conserved in the major storages of Hume and Dartmouth than would otherwise have been the case.

  • On the Edward River system, the flow through the Edward and Gulpa offtakes has averaged 1,600 ML/day and 500 ML/day, respectively. Downstream at Stevens Weir the flow has averaged 750 ML/day and is expected to recede to around 600 ML/day over the coming week. 

  • Flows in the Broken Creek at Rice’s Weir have been steady around 300 ML/day. On the Goulburn River the flow at McCoys is expected to remain well above the end of system target of 350 ML/day with an inter valley trade (IVT) order resulting in a planned flow at McCoys of 1,500 ML/day until the end of January. The IVT order will be reduced in February resulting in a target flow at McCoys of around 1,200 ML/day. IVT deliveries from the Broken, Goulburn and Campaspe systems to the Murray are expected to persist for the next few months under dry conditions to help meet downstream demands in the Murray system.

  • At Torrumbarry Weir, diversions to National Channel are close to 2,200 ML/day with a portion of this water provided to support Murray Cod in Gunbower Creek. Flow downstream of Torrumbarry Weir has started the week around 6,000 ML/day and is now around 5,200 ML/day.

  • Downstream of Torrumbarry, monitoring of the Gunbower and Koondrook-Perricoota forests has identified significant bird breeding events as a result of the natural flooding of the forests. In Gunbower forest around 200 little pied cormorant nests have been identified. Usually little pied cormorant breeding colonies are quite small emphasising how significant this event is. In Koondrook up to 600 breeding pairs of birds have built nests in a wetland in the Koondrook State Forest, known locally as ‘the Pollack’. This is in the forest’s first waterbird breeding event since 1993. See Forestry Corporation media release for more info.

  • On the lower Murrumbidgee River, the flow at Balranald averaged 450 ML/day this week. IVT deliveries have resulted in a rise at Balranald which is forecast to reach to around 2,000 ML/day. Further information on IVT in the Murrumbidgee system is available from WaterNSW.

  • At Euston the flow is around 6,900 ML/day and expected to remain steady this week as the flow from the Murrumbidgee adds to the receding flow on the Murray. The lock at Euston remains closed due to repair works being undertaken on one of the upstream lock gates. More in our media release.

  • On the Darling River, total storage at Menindee Lakes fell by 34 GL to a storage volume of 1,352 GL (78% capacity). Release at Weir 32 averaged 5,000 ML/day.  Even without further flows past Wilcannia, MDBA is not expecting the total volume in the Lakes to fall below about 600 GL by the end of May.

  • At Wentworth, the flow is around 9,400 ML/day and is forecast to recede to around 8,000 ML/day over the coming week. The weir pool at Lock 9 was lowered on Wednesday 25 January to investigate a structural issue at Carrs regulator. The weir pool will remain lowered while the issue is being investigated and updates will be provided as information comes to hand. Lock 8 weir pool continues to be lowered to target 50 cm below FSL and is currently 7cm below FSL. The lowering of Lock 7 weir pool by up to 50 cm is also underway and is currently around 33 cm below FSL.  Weir pool variability helps to restore a more natural wetting and drying cycle to riverbanks along weir pool affected reaches. More information on possible weir pool levels in the coming weeks is available on our website.

  • The storage volume at Lake Victoria fell this week by 30 GL to 516 GL (76% capacity) with the releases from Lake Victoria averaging 4,000 ML/day.

  • The average flow to South Australia was 13,100 ML/day this week which was largely made up of entitlement and additional dilution flow to South Australia. A smaller proportion was environmental water delivered to South Australia including water from upstream sites. Recent high flows to South Australia helped improve connectivity between the Goolwa and Tauwitchere channels and the ocean however they did not scour as much sand at the Murray Mouth as the longer period of high flows in 2010-11. Now that the high flows have passed through the river system, releases over the barrages are being reduced and dredging has again resumed to ensure the Murray Mouth remains open – with only one dredge required at this stage. More info in the SA Department of Environment, Water and Natural Resources media release.

Gu
Photo: NCCMA Genevieve Smith
Little Pied Cormorant nests downstream of Gunbower Forest

 

 


Tagged as

0 Comments

Add new comment

Leave a comment

Filtered HTML

  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Contact us

For news related enquiries:
media@mdba.gov.au

For all other enquiries:
engagement@mdba.gov.au

Postal address:
GPO Box 1801,
Canberra City, 
ACT 2601

By month