The Mildura weir will be temporarily removed for the first time six years to allow high Murray River flows to pass through, the Murray–Darling Basin Authority and Goulburn-Murray Water announced today.
MDBA Executive Director of River Management, Andrew Reynolds said the weir needed to be removed ahead of increased flows expected to arrive by mid-September.
“The work to remove the weir will start later this week or early next week but we will confirm the exact timing when we have a clearer picture of the rate and volume of the flows upstream and when they are expected to arrive at Mildura,” Mr Reynolds said.
“As a rule, we remove the weir when flows are forecast to reach about 42 gigalitres per day, which is currently forecast to happen in the first two weeks of September.”
Prior to removing the weir, the water level immediately upstream will be lowered by between 0.5 and 1.0 metre. As the higher flows arrive, the river will begin to rise again, he said.
“It will take about 8 days to remove the weir and during this time, use of lock 11 is expected to continue for at least the first few days.”
“Without the weir in place, the river will flow freely where the weir usually is, and boats will be able to travel via the river rather than using the lock.”
The weir will be reinstalled once the flow rate drops back below 40 gigalitres per day, said Mr Reynolds.
“When that happens will depend on future rainfall and inflows, but we will notify the community ahead of time.”
“River pumpers, boat operators and other river users are advised to take the changing river levels into account,” he said.
The last time the weir was removed to allow flood waters to pass was in 2016.
The Mildura Weir and Lock 11 are operated and maintained by Goulburn-Murray Water on behalf of the Murray–Darling Basin Authority.