Welcome to your weekly River Murray operations update. Don’t forget to grab the full Weekly Report to read the updated flow advice for the Lower Darling River, courtesy of the NSW Office of Water who are advising that releases from Weir 32 will increase to 7,000 ML per day by the weekend.
River Operations
MDBA active storage increased by 25 GL this week to 8,208 GL (95% of capacity). At Dartmouth Reservoir the storage rose 16 GL to 3,526 GL (91% capacity) with inflows averaging around 3,200 ML/day. The release from Dartmouth continued above minimums due to entitlement releases by AGL Hydro for electricity generation. The flow, measured at Colemans, averaged around 1,000 ML/day during the week and is now at 800 ML/day.
At Hume Reservoir, the release was increased to 18,500 ML/day as additional airspace was targeted in response to forecast rainfall. Over the past week the storage volume fell 16 GL to 2,928 GL (97% capacity). The aim is to have the storage at a level where it can be quickly filled to maximise resources should conditions turn dry but to also provide some airspace to manage higher inflows from potential rain events. As such, the storage volume may be increased or decreased over the coming weeks depending on forecast rain and diversions. Information on upper State shares within each storage can be found via the MDBA water accounting page.
At Yarrawonga, the pool level in Lake Mulwala is currently 124.77 m AHD. Combined diversions at Mulwala Canal and Yarrawonga Main Channel currently total around 3,400 ML/day. The downstream release increased over the week from 17,500 ML/day to 26,000 ML/day.
Sunset on the Wakool - Wakool river in December, 2009. Photo: Emma Coats.
On the Edward-Wakool system the gates have returned to the water at Stevens Weir, and the downstream flow has receded to 6,300 ML/day. Diversions through the Wakool River and Yallakool and Colligen Creek offtakes have also fallen with a current total diversion close to 1,000 ML/day. Downstream on the Edward River, the flow at Leiwah is close to peaking near 6,700 ML/day, while the Wakool River at Stoney Crossing is expected to peak at around 14,000 ML/day in the coming week.
On the Goulburn River the flow at McCoys Bridge averaged around 11,000 ML/day for the week. At Torrumbarry Weir, the gates were returned to the water and the downstream flow is currently 27,500 ML/day and falling. Further downstream, the flow at Swan Hill peaked late in the week at 22,100 ML/day. On the Murrumbidgee River, the flow at Balranald continues to creep up and is currently 11,000 ML/day. At Euston Weir the flow is now 42,500 ML/day and is expected to peak at around 45,000 ML/day in a week’s time.
Total storage at Menindee Lakes is 2,000 GL (116% capacity), an increase of 28 GL from last week, with inflows averaging close to 11,000 ML/day during the week. The flow upstream is expected to peak on the Darling River at Wilcannia next week with high inflows to the lakes continuing for the next few weeks. Releases are currently 4,000 ML/day at Menindee (measured at Weir 32), however they will be increased to 7,000 ML/day by next weekend (see attached media release issued by NSW Office of Water). The flow to the Great Darling Anabranch is around 2,000 ML/day, released from Cawndilla Outlet. Downstream on the Darling River at Burtundy, the flow has increased to 4,200 ML/day and will continue rising over the second half of August.
At Lake Victoria, the volume decreased by 3 GL this week and is now at 428 GL (63% capacity). The storage level will rise over the coming weeks, as higher flows arrive from upstream, and water is stored to maintain the flow to South Australia at around 40,000 ML/day. The flow to South Australia is currently 39,700 ML/day.
At the Lower Lakes, the 5-day average level at Lake Alexandrina has decreased 10 centimetres over the week to 0.65 m AHD. The level is expected fall away further toward the target level of 0.55 m AHD over the next week to assist in drawing higher salinity water from Lake Albert. Plots showing short term forecast flows and levels for selected key sites are updated each week and are available on the MDBA website.