Providing plants on the banks of the lower Goulburn River a well-needed late summer drink could also encourage golden perch to migrate from the Murray River to the Goulburn.
Goulburn Broken CMA Environmental Water Manager Simon Casanelia said an environmental water “fresh” would be delivered along the Goulburn River below the Goulburn Weir from late February and through March.
“The annual monitoring that we’ve been conducting, shows that using environmental water to ‘top up’ the water that is being delivered to irrigators and other users at this time of the year has helped bank-stabilising plants establish along the lower Goulburn,” Mr Casanelia said.
“And, because of this vegetation, we saw far less bank slumping and erosion during the natural flooding we experienced late last year than we did during 2010 to 2012.”
Water for the increased flow is due to be released from Goulburn Weir from Sunday February 26, with the peak of about 4,600 ML/day reaching McCoy’s Bridge by March 9. The flow will be well below minor flood level. In the event of heavy rain, the timing and size of the environmental flow could change.
The table below shows how river heights and flows will change during this period:
The environmental water will also improve water quality and provide food and shelter for waterbugs and native fish.
“During the hot, dry weather it’s important to have refuge pools for aquatic animals,” Mr Casanelia said.
“Improved water quality will also help crayfish, shrimps, water bugs and native fish continue to recover after the blackwater event earlier this year.”
The blackwater event was caused by debris-rich run-off from tributaries entering the Goulburn River after heavy rain on December 29. It was not caused by environmental water.
“We’re keen too to see if the higher flows in the Goulburn River at this time of the year attract native fish, particularly golden perch, to move here from the Murray.”
In past years, environmental water delivered in spring has triggered golden perch spawning in the Goulburn River.
“While we’ve found lots of eggs in the Goulburn, only low numbers of young fish have been reported. The reason for this is unclear, although it seems highly likely that the eggs and juvenile fish move downstream into the Murray. We hope the higher flows in the Goulburn at this time of the year will attract more young perch back into the Goulburn.”
As part of the monitoring program funded by the Commonwealth Environmental Water Office fish ecologists from the Arthur Rylah Institute will use acoustic tracking to determine if fish move into the Goulburn from the Murray in response to the fresh.
Environmental flows are planned by the Goulburn Broken CMA in consultation with the Commonwealth Environmental Water Office and managed by Goulburn-Murray Water in line with the Victorian Environmental Water Holder’s Seasonal Watering Plan 2016-17. Timing of the environmental flows take into consideration delivery orders by irrigators and other water users and feedback from the community via the Goulburn Broken CMA’s environmental water advisory groups.
Environmental watering is only one way of protecting and improving rivers and wetlands. Fencing and revegetation, erosion control, pest control, returning logs to rivers for fish and bug habitat, and installation of fishways to allow fish to pass through dams and weirs also help.