Another bumper edition of the full River Murray Weekly Report is available on the MDBA website in pdf and doc formats, with a wealth of data on river levels, flows, salinity and water storages. Or, for those of you eager to find out in the latest from river operations, just read on…
River Operations
MDBA active storage increased by 49 GL during the week and is currently 7,080 GL (82% capacity) – mainly due to an increase in volume at the Menindee Lakes. At Dartmouth Reservoir, the storage volume increased by 5 GL and is now 3,189 GL (83% capacity). The release from Dartmouth, measured at Colemans, remained at 200 ML/day. At Hume Reservoir, the storage volume decreased by 39 GL during the week and is now 2,617 GL (87% capacity). The release from Hume was increased early in the week to meet downstream demands, but has been cut back slightly in the last few days and is currently targeting a flow downstream at Doctors Point of 11,000 ML/day. The release may be reduced slightly further during the coming days.
A look back: Yarrawonga Weir on 12 October 1937
At Yarrawonga Weir, the pool level is currently 124.73 m AHD, which is close to the normal operating level. It is expected to remain relatively steady over the coming days. Diversion from Lake Mulwala has averaged around 4,500 ML/day at the Mulwala Canal and around 1,300 ML/day into the Yarrawonga Main Channel. The release from Yarrawonga Weir is currently 7,500 ML/day, and now includes some Commonwealth environmental water to add an additional in-channel dilution flow along the River Murray and Edward-Wakool system. This additional flow will assist in managing blackwater with low dissolved oxygen levels that continues to flow into the river system from several tributaries following the recent over-bank flooding. More information is provided in the attached water quality bulletin.
On the Edward-Wakool system, diversion into the Edward River has decreased only slightly and is currently 1,500 ML/day through the Edward River offtake and 340 ML/day through the Gulpa Creek Offtake. Downstream at the escapes, there continues to be 2,100 ML/day released via the Edward escape and 300 ML/day through the Wakool escape; while diversion through the Wakool River, Yallakool Creek and Colligen Creek regulators has been decreased. At Stevens Weir, the release has averaged around 2,400 ML/day during the week, which is slightly up from the previous week. On the Billabong Creek, high flows at Darlot have now peaked and subsequently dropped below 5,000 ML/day in the last few days. Downstream on the Edward River, the flow at Moulamein has also peaked, but is now receding only slowly with the current flow just under 9,000 ML/day. Downstream on the Wakool River at Kyalite, the flow continued to fall away, decreasing from 15,800 to 12,800 ML/day during the week.
On the Goulburn River, the flow at McCoys Bridge increased slightly as expected, reaching a flow of 3,900 ML/day. At Torrumbarry Weir, diversion into the National Channel has been increased from around 2,000 to 2,700 ML/day, while the flow downstream of the weir decreased to 8,300 after remaining fairly steady for much of the week. The flow is expected to decrease only slightly over the coming days. At Swan Hill, the river continued to recede and is now flowing at 7,800 ML/day.
On the Murrumbidgee River, the flow at Balranald increased considerably over the last few days as the main flood peak approached. The flow is now around 25,000 ML/day and the Bureau of Meteorology is forecasting a peak close to 6.8 m on 20 April with minor to moderate flooding. For information regarding flood warnings please refer to the Bureau of Meteorology website.
At Euston, the flow eased back from the previous week’s peak, but has now re-commenced rising as Murrumbidgee inflows increase. The flow is currently 32,000 ML/day and is expected to slowly increase over the coming days, and although it is not expected to exceed the recent peak, the river at Euston should continue to flow at rates above 30,000 ML/day into early May.
Downstream at Mildura, the weir has now been re-instated following the period of higher flows and the pool level has been raised over the last few days. The level is now at 34.35 m AHD or 5 cm below the normal operating level.
On the Darling River, the flow at Wilcannia peaked at 10.63 m over the weekend with major flooding, and has dropped only slightly since then. The peak is expected to be broad, and combined with flow from the Talyawalka Creek, will maintain high inflows to the Menindee Lakes for several weeks. At Menindee Lakes, the storage volume has increased by 106 GL to 1,538 GL (89%). The lakes will continue to rise over the coming weeks. Release from the Lakes (measured at Weir 32) has been reduced from 35,000 to 30,500 ML/day during the past week and is expected to decrease to 25,000 ML/day in the coming days. Further reductions to the release will then be undertaken over the coming weeks resulting in more water pushing into the lakes, enabling them to refill while managing the recession along the lower Darling River. Downstream at Burtundy the flow continues to rise slowly but steadily, and has now reached 19,400 ML/day. For further information on the flood operations at Menindee Lakes, please refer to the NSW Office of Water website.
At Wentworth, the river peaked at 58,400 ML/day then dropped slightly over the last week to the current flow of 56,400 ML/day. Although the level remains 7 cm above the normal pool height, the weir has now been re-instated and normal pool level will now be targeted.
At Lake Victoria, the storage volume decreased by 24 GL and is currently 410 GL (61% capacity). The flow to South Australia has averaged 59,300 ML/day over the past week and is expected to remain close to this value during the coming week.
At the Lower Lakes, additional Barrage gates were opened during the week as favourable weather conditions returned. Flow to the sea increased as a result and the average level in the lakes dropped by 8 cm to 0.66 m AHD (9 cm below full supply level). Higher tides over the coming weeks may result in further gate closures, and with the current high inflows, the Lower Lakes are expected to rise again.
Love the vintage photos!