River Murray Ops Update – 8 August

Welcome to this week’s River ops update, which also includes a summary of conditions over the past month and details of the Basin Plan community meetings.

Basin Plan Community update meetings

Another round of community updates on work under the Basin Plan will be held in the southern Murray–Darling Basin next month.

The MDBA will be hosting meetings in the following towns:

  • Goolwa
  • Murray Bridge
  • Renmark
  • Mildura
  • Shepparton
  • Deniliquin
  • Griffith

For further details and how to register your attendance see our latest media release.

River Operations

MDBA total storage rose by 121 GL this week, with the active storage now 6,157 GL (73% capacity).

At Dartmouth Reservoir, the storage volume increased by 28 GL to 3,632 GL (94% capacity). The release is steady at 200 ML/day. A short flow pulse may be released in the coming week to manage water quality and ecosystem functions in the Mitta Mitta River. A flow advice will be issued if this operation proceeds.

Inflows into Hume Reservoir over the past week averaged 14,000 ML/day, increasing the storage by 93 GL to 2,141 GL (71% capacity). The release remains at the minimum rate of 600 ML/day. Inflows from the Kiewa River downstream of Hume maintained the flow in the Murray at Doctors Point at an average of 4,000 ML/day.

At Lake Mulwala, the major irrigation offtakes continue to prepare for the coming irrigation season. Mulwala Canal has been diverting 1,500 ML/day, whilst Yarrawonga Main Channel is expected to re-commence channel filling next week. The release from Yarrawonga Weir is steady at around 11,500 ML/day, however it will be lowered over the coming week as inflows from the Ovens River recede. Once the release falls below the downstream channel capacity of the Barmah Choke (around 10,600 ML/day), regulators currently diverting water into Barmah-Millewa Forest are planned to be closed.

Lake Pamamaroo, Menindee Lakes. Photo: MDBA.

Lake Pamamaroo, Menindee Lakes. Photo: MDBA.

In the Edward-Wakool system, flows through the Edward and Gulpa River offtakes are 1,500 ML/day and 500 ML/day respectively. Both these offtakes are fully open, with their flow varying in response to the water level in the Murray at Picnic Point. Flows through these offtakes are likely to marginally increase next week, as the closing of the Barmah-Millewa Forest regulators is expected to raise the water level in the main Murray channel. On the Edward River at Toonalook, the flow is 4,000 ML/day and receding, whilst downstream at Stevens Weir the release is around 3,000 ML/day.

On the Goulburn River, the flow at McCoys Bridge is 7,500 ML/day. The flow at McCoys Bridge has been fluctuating around 6,000-8,000 ML/day over the past fortnight due to tributary inflows entering the Goulburn downstream of Eildon Dam. Typically some of these flows would be diverted into Waranga Basin – an off-river storage connected to Goulburn Weir – however the storage currently has limited airspace. On the Campaspe River, environmental water released from Lake Eppalock is currently passing Rochester with a peak of 1,650 ML/day. This flow will gradually reduce over the coming week.

At Torrumbarry Weir, diversions at National Channel increased this week from 1,650 ML/day to 3,300 ML/day. Of this volume, around 700 ML/day is being diverted into Gunbower Forest and 400 ML/day is passing down Gunbower Creek. The remainder is being directed into Kow Swamp, one of the Victorian mid-Murray storages.

On the Murrumbidgee River, the flow at Balranald peaked this week at 5,000 ML/day and has now reduced to 4,200 ML/day. The flow at Balranald is expected to continue receding to around 1,500 ML/day over the next week. Back on the Murray at Euston, the weir pool is currently 40cm above the Full Supply Level (FSL) of 47.6 m AHD. The flow downstream of Euston is at a peak of 24,000 ML/day, and forecast to remain above 20,000 Ml/day over the coming week.

Downstream of Euston, environmental water is continuing to be pumped into Hattah Lakes. Water has now progressed throughout the majority of the Lakes system, including up to the most northern bank of Lake Bitterang. This is only the second time Lake Bitterang has received water since the 1970’s. Water will continue to be pumped into the Lakes for about another four weeks, and then will be held for a period of time before returning back to the Murray.

At Mildura Weir, the pool level is currently 8 cm below FSL and gradually refilling following the completion of trestle upgrade works. Storage in Menindee Lakes decreased by 7 GL this week to 363 GL (21% capacity). The release at Weir 32 remains at a minimum flow of 200 ML/day. A spike in salinity has been observed slowly progressing down the lower Darling since early June. The salinity at Burtundy is forecast to reach 1,000 EC in the coming fortnight before returning back to around 700 EC. This is expected to have minimal impact on salinity levels in the Murray.

At Wentworth Weir, the downstream flow is 21,000 ML/day and rising. A peak flow past Wentworth of around 23,500 ML/day is forecast for next week. At Weirs and Locks 9 and 8, the pool levels are being raised to around 15 cm and 40 cm above FSL. This is part of a trial to introduce variations in the weir pool levels to achieve a more natural wetting and drying cycle for the riverine environment.

At Lake Victoria, the storage volume increased by 6 GL to 578 GL (85% capacity). Inflows into Lake Victoria are planned to be gradually increased over the coming week to ensure the storage is full when unregulated flows cease. Flow to South Australia is currently 18,000 ML/d and forecast to remain above 15,000 ML/day for the coming week.

At the Lower Lakes, the 5-day average water level in Lake Alexandrina is currently 0.82 m AHD. The release from the barrages is estimated to be around 2,000 ML/day.

 July 2014 Summary

It was mainly dry across the Murray–Darling Basin during July, with widespread below average rainfall recorded in most areas. Across the Basin as a whole, the Bureau of Meteorology has reported area-averaged rain totalling just 17.3 mm, which is 56% below the long-term mean and the 16th driest July in 115 years of record.

There were patches of very much below average rain in the far north, the far south-east — including parts of the upper Murrumbidgee and upper Mitta Mitta River catchments — and through western NSW where some gauges received no rain at all for the month. Rainfall was closer to average or above average over southern South Australia and along much of the southern Great Dividing Range. Notably, this included most of the Victorian Alps and NSW Snowy Mountains where the passage of multiple winter cold fronts provided regular rain, alpine snow and a considerable boost to stream flows in the upper Murray catchments over the past few weeks.

The generally clear and dry conditions also resulted in above-average daytime temperatures across the Basin during July, despite several significant cold weather events affecting the south. However, the clear skies also contributed to cold overnight temperatures, heavy frosts in some areas and below average minimum temperatures for most of the Basin.

*** For even more information (plus maps, graphs and data), read the latest River Murray Operations Report ***

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One comment to River Murray Ops Update – 8 August

  1. Thanks for the meeting details. (Gorgeous shot with those colours by the way). Laurelle J

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