Here’s the latest update on River Murray operations. The full River Murray Weekly Report is on our website.
MDBA active storage increased by 200 GL during the week and is currently 7,280 GL (85% capacity). At Dartmouth Reservoir, the storage volume increased by 7 GL and is now 3,196 GL (83% capacity). The release from Dartmouth, measured at Colemans, remained at 200 ML/day. At Hume Reservoir, the storage volume increased by 1 GL during the week and is now 2,618 GL (87% capacity). The release from Hume was progressively cut back for most of the week as downstream demands fell away. The release has been increased slightly over the last few days to a target at Doctors Point of 7,000 ML/day as tributary inflow began to recede again, and may be increased a little further in the coming days.
At Yarrawonga Weir, the pool level is currently 124.78 m AHD. It is expected to decrease towards a target level of 124.70 m AHD over the coming days. Diversion from Lake Mulwala has decreased from around 4,600 to 3,500 ML/day at the Mulwala Canal and from around 1,300 to 200 ML/day into the Yarrawonga Main Channel. These decreases are normal at this time of the year when approaching the end of the irrigation season. The release from Yarrawonga Weir remains at 7,500 ML/day, with additional in-channel dilution flow being maintained using Commonwealth environmental water to assist in managing low oxygen water currently flowing in from some tributaries further downstream on the River Murray system.
On the Edward-Wakool system, diversion into the Edward River has remained fairly steady with around 1,500 ML/day flowing through the Edward River Offtake, 350 ML/day through the Gulpa Creek Offtake and 2,100 ML/day through the Edward Escape. At Stevens Weir, the release has remained fairly steady, averaging just under 2,500 ML/day during the week. On the Billabong Creek, there is still a high flow at Darlot, but it has now dropped to around 2,200 ML/day and should continue to fall away over the coming weeks. Further downstream, all gauges from Moulamein to Kyalite are on a slow but steady recession, as the high inflows following the early March floods move through the system and back into the Murray. The current flow at Kyalite is estimated to be around 11,000 ML/day.
On the Goulburn River, the flow at McCoys Bridge increased from 3,900 to 4,400 ML/day. Goulburn-Murray Water advises that a flow above 6,000 ML/day is likely over the coming week. At Torrumbarry Weir, diversion to the National Channel has now been cut back from 2,700 to 2,100 ML/day, and this in combination with higher inflows through Rices Weir and the Goulburn River has caused the downstream flow to rise back to 10,000 ML/day. The flow should increase slightly more in the coming days.
On the Murrumbidgee River, the flow at Balranald is currently steady near its peak of 6.79 m with a flow of just under 30,000 ML/day causing minor flooding. For information regarding flood warnings please refer to the Bureau of Meteorology website at.
Downstream at Euston, the flow continued to rise slowly during the week as Murrumbidgee flood waters flowed into the Murray. The flow is now at around 37,000 ML/day, which is similar to the peak flow observed earlier in April. The river here is still rising, but at this stage, is only expected to increase slightly more over the coming week.
On the Darling River, high inflows to the Menindee Lakes are continuing, averaging almost 60,000 ML/day over the past seven days. The lakes have continued to rise during this period and are now back in surcharge and storing 1,765 GL (102%), which is an increase of 227 GL since last week.
Release from the Lakes (measured at Weir 32) has been reduced from 30,500 to 23,500 ML/day, and the release will be reduced further over the coming weeks as inflows start to drop away.
Downstream at Burtundy the flow crept slightly higher, and is now flowing at 19,700 ML/day. On the Great Darling Anabranch, the channel remains fully connected from Menindee Lakes to the Murray with floodwater that has progressed down from the upper Darling catchments now moving towards the lower reaches of this system. Historically, flow events through the Great Darling Anabranch are very slow and considerably attenuated. Inflows to the River Murray from the current event are expected to finally arrive during late autumn and then continue into the winter period. For further information on the flood operations at Menindee Lakes, please refer to the NSW Office of Water website.
At Wentworth, the flow eased for much of the week, decreasing to 53,000 ML/day before renewed rises began as higher flows arrived from upstream. The current flow is 54,600 ML/day and the upstream pool has risen again to be 8 cm above the normal level. Flows should rise further here during the coming week. At Lake Victoria, the storage volume decreased by 35 GL and is currently 375 GL (55% capacity), and the flow to South Australia has averaged 57,900 ML/day.
At the Lower Lakes, the operational focus has shifted in recent weeks to pass the unseasonal high inflows resulting from upstream flood waters caused by heavy rain in early March. The Barrages are being managed to balance the need to pass the flow while also protecting the Lower Lakes from periodic reverse flow of sea water due to high tides, strong winds and high water levels in the Coorong. Barrage gates at Goolwa and Mundoo were closed during the week to limit saline incursions from reverse flows resulting from several days of high tides combined with strong south-west winds. With the flow past Lock 1 now in excess of 50,000 ML/day, average lake levels rose accordingly, increasing by 5 cm to 0.71 m AHD (4 cm below FSL). It is expected that conditions will enable these Barrage gates to be re-opened over the coming days.