This week’s update is an interesting breakdown of what the recent rainfall has meant in terms of inflows to the rivers, and how that in turn changes storage levels. There’s even more information in the full weekly report on our website.
MDBA active storage increased by 223 GL during the week and is currently 6,993 GL (81% capacity). At Dartmouth Reservoir, the storage increased by 40 GL and is now 3,129 GL (81% capacity). The release from Dartmouth, measured at Colemans, was 200 ML/day. At Hume Reservoir, the storage increased by 180 GL during the week and is now 2,581 GL (86% capacity). The release from Hume was held at the minimum 600 ML/day for the week.
At Yarrawonga Weir, the pool level is currently 124.78 m AHD. Diversions at Mulwala Canal increased to 2,000 ML/day during the week however the majority of this water will be escaped to the Edward and Wakool Rivers to dilute the black water returning to these rivers from the forest and help maintain higher dissolved oxygen levels for fish populations (in particular the Murray Cod). Diversions at the Yarrawonga Main Canal are currently 450 ML/day. The release from Yarrawonga Weir reduced from 62,000 ML/day at the start of the week to the current rate of 12,500 ML/day.
On the Edward-Wakool system, the Edward River and Gulpa Creek offtakes are currently diverting 2,200 ML/day and 970 ML/day respectively. These flows will reduce over the coming week as the River Murray level falls away. The flow in the Edward River at Toonalook and inflow from Bullatale Creek are continuing to rise (currently 9,700 ML/day and 4,600 ML/day respectively), while the inflow from Tuppal Creek is now falling away (currently 2,000 ML/day). The flow in the Edward River at Deniliquin is currently around 15,000 ML/day and expected to peak at around 17,500 ML/day on the weekend. Inflow from Edward Escape will commence in the coming week. A total of around 3,200 ML/day is being diverted at the Wakool, Yallakool and Colligen Creek regulators. The gates at Stevens Weir were removed from the water on Monday 12th March. The flow downstream of the weir is currently 9,800 ML/day and is expected to rise to around 13,000 ML/day in the coming week. Inflow from the Billabong Creek is currently 2,900 ML/day and rising.
The flow in the River Murray at Torrumbarry Weir peaked late in the week at around 34,000 ML/day and is currently 32,500 ML/day. The flow at Swan Hill is 20,600 ML/day and forecast to peak at around 21,500 ML/day on the weekend. Further downstream, the inflows from the Murrumbidgee River (currently 8,900 ML/day measured at Balranald) and the Wakool River (estimated around 4,300 ML/day) have helped the River Murray downstream of Euston Weir rise almost two metres over the week to a flow of 23,000 ML/day.
At Menindee Lakes, the storage volume decreased 20 GL to 1,455 GL (84% capacity) during the week. Releases from the Lakes (measured at Weir 32) averaged around 34,800 ML/day. The gates are again free of the water at Lake Wetherell. They will be returned to the water when the higher flows arrive from upstream. When this occurs the operational intent is to maintain the release at 35,000 ML/day and capture and store the additional flow in the Lakes. On the lower Darling, the flow at Burtundy rose 500 ML over the week and is currently 16,900 ML/day. For further information on the flood operations at Menindee Lakes, please refer to the NSW Office of Water website.
At the confluence of the Murray and Darling Rivers at Wentworth, the flow is currently 34,800 ML/day and rising. Further downstream, the storage volume at Lake Victoria increased by 24 GL over the week to 502 GL (74% capacity) as water was captured to maintain the flow to South Australia at around 21,000 ML/day in order to allow essential construction works at Chowilla and Lock 4. Over the next few days, the flow to South Australia will increase to around 24,000 to 25,000 ML/day, however this will be exceeded next week when higher flows arrive and the re-regulation capacity of Lake Victoria storage is exceeded. It is expected that the flow will gradually increase over the coming weeks and be between 40,000 and 60,000 ML/day by mid April. It is possible that the flows may increase above 60,000 ML/day as flow estimates improve. At this stage, the flow to SA is not expected to reach the 93,800 ML/day observed in mid February 2011, but this could change if there is further significant rainfall.
The average level of the Lower Lakes fell by 14 cm to 0.59 m AHD during the week. The Lakes will be drawn down to around 0.5 m AHD for a few weeks, before refilling in an effort to improve the salinity of Lake Albert. The release from the Barrages is currently targeting a flow of around 26,600 ML/day.