River Murray Operations Update – 24 January

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River Murray Ops Update – 24 January   MDBA

River Operations

MDBA active storage decreased by 172 GL this week and is currently 5,941 GL or 69% capacity. At Dartmouth Reservoir, storage decreased by 30 GL to 3,588 GL (93% capacity). The release, measured at the Colemans gauge, was reduced during the week from a flow of 6,000 ML/day to 2,500 ML/day. The flow will remain steady at this rate over the coming week.

At Hume Reservoir, the storage volume decreased by 81 GL to 1,880 GL (63% capacity). The release was highest at the beginning of the week – around 21,000 ML/day – during the heatwave across the southern Basin. This has now reduced to 18,500 ML/day and is likely to reduce further this week based on forecast rain.

Periods of intense heat generally correspond with a spike in power demand, which in turn can prompt a rapid increase in hydro-electricity power generation. This was observed during the past week, with a sharp rise in the release of water through the Snowy Mountains Scheme, resulting in a contribution of 12 GL into the upper River Murray system, which was captured in Hume Reservoir.

At Yarrawonga Weir, the total diversion at the irrigation offtakes remained steady at around 66 GL this week. The pool level in Lake Mulwala is currently 124.84 m AHD and is expected to remain above 124.75 m AHD over the Australia Day long weekend. The downstream release is steady at around 10,100 ML/day.

Flows are expected to remain at or near channel capacity rates in Barmah-Millewa Forest through the remainder of summer. This is due to limited water availability in Menindee Lakes combined with expected ongoing high demands. This is good news for recreational users of the river, as river levels will remain relatively high for this time of year. Please bear in mind that MDBA can make no guarantees about river levels in any particular reach on any particular day as operations may need to be adjusted in response to weather and demand conditions. River users can keep up to date on current and forecast conditions on the MDBA’s river flows and levels page.

On the Edward River system, flow through the Edward and Gulpa Creek offtakes averaged 1,600 ML/day and 600 ML/day respectively. Flow through Gulpa Creek is planned to decrease to 500 ML/day in the coming week as a bird breeding event in Reed Beds wetland reaches its final stages.
Reed Beds wetland, Millewa Forest

Reed Beds wetland, Millewa Forest: the location of a current bird breeding event Photo: Ian Davidson

At Stevens Weir, the downstream flow is around 1,200 ML/day. Diversions to the Wakool River are about 100 ML/day, with approximately 320 ML/day flowing into Yallakool Creek. Wakool Main Canal diversions rose again this week from 1,850 ML/day to 2,100 ML/day in response to warmer temperatures. The flow in the Edward River at Moulamein has fallen this week from 1,300 ML/day to 1,100 ML/day while the Niemur River at Mallan School has receded from 240 ML/day to 135 ML/day.

On the Goulburn River at McCoys Bridge this week, the flow peaked at 2,900 ML/day and is now expected to steadily recede in line with the delivery pattern of inter-valley transfer water from the Goulburn Valley to the Murray Valley. At Torrumbarry Weir, the diversion at National Channel remained steady at 3,000 ML/day. The downstream release increased from 4,700 ML/day to 5,800 ML/day as higher flows arrived from the Goulburn River.

On the lower Murrumbidgee River, the flow at Balranald has continued to recede and is now about 300 ML/day. Downstream on the Murray at Euston, the flow has reduced from 6,000 ML/day to 5,000 ML/day. The flow at Euston will continue receding for a few more days before higher flows arrive from Torrumbarry Weir.

At Menindee Lakes, the storage volume decreased by 40 GL over the last week to 568 GL (33% capacity). Release from the lakes is currently around 1,350 ML/day at Weir 32 and continues to be gradually reduced. At Burtundy, the flow has fallen from 3,000 ML/day to 2,300 ML/day and will continue to recede.

On the River Murray, downstream of the Darling confluence, the flow at Wentworth Weir has fallen from 8,000 ML/day to around 5,300 ML/day. This is due to a combination of hot weather, decreasing releases from Menindee Lakes and decreasing flows from the River Murray upstream of the confluence.

At Lake Victoria, the storage volume decreased by 21 GL to 579 GL (86% capacity). The flow to South Australia is currently averaging around 7,200 ML/day and will be targeting 7,450 ML/day for the remainder of January. At the Lower Lakes, the 5-day average level has decreased to 0.70 m AHD and the estimated release through the barrages is approximately 800 ML/day.