Did you know that the full River Murray Ops report includes graphical data on the Murray system monthly inflows? Or data on river levels and flows of both the Murray and tributaries? If you didn’t, then you’ve been missing out on a wealth of extra information!
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River Operations
MDBA active storage increased by 57 GL during the week to 7,930 GL (92% capacity). At Dartmouth Reservoir, the total storage increased by 23 GL to 3,342 GL, which is 87% capacity.
At Hume Reservoir, the storage volume has increased by 3 GL to 2,867 GL (95% capacity) and the release increased to a peak of 15,000 ML/day during the week to pass inflows as they arrived following last week’s rain. The release has since been decreased to 10,500 ML/day and the storage level is being maintained to provide the current airspace target of about 140 GL. This target remains under constant review and will be used to help provide limited flood protection to downstream communities during winter. The target will vary depending on rain, inflow and demand forecasts. Communities are advised to have their flood preparations in place and remain vigilant. See the NSW SES FloodSafe website for further information.
Downstream at Yarrawonga, the pool level in Lake Mulwala is currently 124.76 m AHD. Release from Yarrawonga Weir was increased from 8,500 to 24,000 ML/day as inflows rose. The release will be decreased steadily over the coming days but current rainfall forecasts suggest it will remain above at least 15,000 ML/day during the next week.
Downstream in the Barmah-Millewa forest, regulators have been opened as flows begin going over bank through the Barmah Choke. The flow at the Barmah gauge has increased to 7,200 ML/day and will keep rising towards 10,000 ML/day in the coming week.
On the Edward-Wakool system, flows through the Edward and Gulpa offtakes have been increased as higher flows arrive. With the addition of overbank flow through the Millewa forest, about 5,000 ML/day is expected at Deniliquin in early July. At Stevens Weir, additional water is being stored in the weir pool, with the level being increased from about 0.8 to 2.7 m on the local gauge. As the pool level rises, around 400 ML/day and 250 ML/day will also be diverted through the Yallakool and Colligen Creek offtakes. These measures are being undertaken to restrict flow downstream of Stevens Weir to assist fishway works.
On the Goulburn River, Goulburn-Murray Water has advised that releases have been increased at Eildon Reservoir following the weekend rain. These releases combined with increasing inflows downstream have led to rises along the lower Goulburn River. The flow at McCoys has increased from 1,300 to 9,700 ML/day with further rises expected. At Torrumbarry Weir, the flow has increased to 10,400 ML/day and is expected to approach 20,000 ML/day in the coming week.
On the Murrumbidgee River, the flow at Balranald has increased from 7,800 to 9,200 ML/day and should increase slightly further in the coming days. At Euston Weir, the flow has increased steadily this week and is now up to 16,600 ML/day. A flow in excess of 25,000 ML/day is expected by mid July.
At Menindee Lakes, the storage increased by just 1 GL, and the total storage remains surcharged at 1,918 GL (111% capacity). The release, measured at Weir 32, is currently 570 ML/day and will be eased back to the normal minimum for surcharged conditions of about 500 ML/day in the week ahead.
At Lake Victoria the rate of filling has slowed in line with the Lake Victoria Operating Strategy as there are now sufficient flows in transit to enable a later filling date. The storage increased by 30 GL to 477 GL (70% capacity). The flow to SA decreased to a low of 13,300 ML/day during the week but has since increased to 17,000 ML/day as a result of higher releases from Lake Victoria and higher flows arriving in the Murray from upstream. It is expected to exceed 20,000 ML/day during July.
The 5-day average level at the Lower Lakes is currently 0.60 m AHD (0.15 m below FSL). This is an increase of 5 cm and follows heavy local rain and the closure of more than half the Barrage gates. Barrage operations aim to continue increasing the Lower Lakes level towards full supply over the coming weeks.