It was dry almost right across the Basin this week. We’ve got the latest below on how the rivers have run, but in the full report on our website you’ll also see information about rainfall and inflows.
MDBA active storage increased by 5 GL this week and is now 7,524 GL (88%). At Dartmouth Reservoir, storage increased by 6 GL to 3,215 GL (83% capacity) and release remains at 200 ML/day. At Hume Reservoir, the storage increased by 5 GL to 2,631 GL (88% capacity). The release has been cut back each day this week and is now at 1,800 ML/day. Further reductions are expected in the coming days with the release potentially decreasing towards the seasonal minimum of 600 ML/day.
At Lake Mulwala, the pool level was lowered to 124.62 m AHD during the week ahead of the cessation of diversions to Mulwala Canal and the Yarrawonga Main Channel which occurred late in the week. These channels are now being drained and will remain closed for around three months. The level of Lake Mulwala, currently 124.73 m AHD, is now expected to rise above 124.8 m AHD in the coming days. Release from Yarrawonga Weir has been reduced to 4,000 ML/day with further reductions expected in the coming week.
On the Edward-Wakool System, flow through the Edward and Gulpa offtakes has been decreased and will continue to fall as the River Murray recedes upstream. The flow in the Edward River at Toonalook is now 1,300 ML/day, while downstream at Stevens Weir, the flow increased to almost 2,000 ML/day as the end of season drainage of irrigation channels continued bringing return flows back to the river.
On the Goulburn River, the flow at McCoys Bridge decreased as expected, dropping from 6,500 to 3,600 ML/day. At Torrumbarry Weir, the flow receded to as low as 7,700 ML/day during the week, but is currently back up at 8,900 ML/day following the seasonal closure of National Channel. A recession in flows is now expected to re-commence as the coming week unfolds. On the Murrumbidgee River, the flow at Balranald is currently 14,500 ML/day and falling each day by around 500 ML/day. At Euston, the Murray decreased to below 30,000 ML/day on 14 May and is now flowing at 27,500 ML/day. The flow is expected to keep falling away here for several weeks to come.
On the Darling River, inflow to the Menindee Lakes receded considerably this week, averaging around 18 – 20,000 ML/day during the last 7 days. The combined volume of the lakes topped out on 11 May at 2,028 GL, or 22 GL below the maximum surcharge level. The volume has since eased back and is currently at 2,003 GL (116%). Release from Menindee (measured at Weir 32) has held at around 17,000 ML/day for most of the week, but is now at around 16,000 ML/day and will now be reduced further as inflows continue to drop away. Downstream on the lower Darling, the flow at Burtundy, currently 19,500 ML/day, has begun to recede slowly from its peak of around 20,000 ML/day. For further information on the flood operations at Menindee Lakes, please refer to the NSW Office of Water website with details available here.
At Wentworth, the flow has receded to 51,800 ML/day and the pool is now back close to the normal operating level. Storage at Lake Victoria is fairly steady; however inflow to the lake will be increased resulting in a slight rise in lake levels next week. Flow to South Australia has decreased to 50,600 ML/day, and will gradually reduce to 45,000 ML/day early next week.
At the Lower Lakes, adverse tidal and wind conditions forced gate closures at Goolwa and Mundoo at times throughout the week. Average lake levels have increased following these closures and the 5 day average level for Lake Alexandrina is now 0.81 m AHD which is 10 cm higher than this time last week and 6 cm above FSL. The average level should gradually reduce in the coming days.