Recovering riverbank vegetation will receive a welcome drink with a delivery of water for the environment planned for the lower Goulburn River during late autumn.
Goulburn Broken Catchment Management Authority’s Simon Casanelia said the water would help boost the growth of vegetation that had established on the riverbanks during spring and summer.
“An autumn environmental flow aims to water vegetation higher up on the riverbank that has dried over summer, giving it a chance to grow before winter,” Mr Casanelia said. “It will also benefit water bugs and instream productivity to support native fish.”
The autumn environmental flow is included in the seasonal watering plan each year, but its delivery is dependent upon vegetation and riverbank conditions.
“The interim arrangements put in place over the past two irrigation seasons to protect the riverbanks have been effective. This year we have seen some regrowth of vegetation on the lower banks that were left bare after the prolonged unseasonal high summer flows in previous years. This vegetation provides important habitat for native fish and water bugs, which are an important food source for fish,” Mr Casanelia said.
Acting Water Minister Richard Wynne recently released a regulatory impact statement that includes options for progressing from interim to enduring arrangements to protect the health of the lower Goulburn River whilst maximising trade opportunities within ecological tolerances. Further information and opportunities to have your say are available on the Engage Victoria website at https://engage.vic.gov.au/goulburn-murray-trade-rule-review
Mr Casanelia said last year’s wet winter, which included several natural higher flow events, followed by a delivery of water for the environment in spring, had brought a lot of sediment and seed to the banks of the Lower Goulburn.
“The favourable early season conditions combined with lower flows over summer have led to less erosion, more stable banks and improved vegetation on the Goulburn River’s banks. This means the autumn environmental flow can go ahead.”
From Thursday April 15, water for the environment will start to be released from Goulburn Weir. The releases will gradually increase to about 6,000 megalitres (ML) a day by April 24 (a river height of 4.1m at Shepparton) and then reduce back to current levels of about 1000 ML a day (2.7m at Shepparton) by May 12. This is well below minor flood level (9.5m at Shepparton). The environmental flow has been designed to recede slowly, which is better for the river’s banks. If there is heavy rain, environmental flow releases may be reduced.
Mr Casanelia said a lower river was particularly popular with holidaymakers because it provided better access to sandbars and dry riverbanks.
“The delivery of the autumn environmental flow has been timed to avoid a high river during Easter, which means visitors can access the river for recreation, while still meeting ecological needs.”
The response of vegetation to the water delivery, as well as bank condition, fish and bugs will be measured as part of the Commonwealth Environmental Water Office’s Monitoring Evaluation and Research (Flow-MER) project.
Environmental flows are planned by the Goulburn Broken CMA in consultation with the Commonwealth Environmental Water Office and the Victorian Environmental Water Holder. The delivery is managed by Goulburn-Murray Water in line with the VEWH’s Seasonal Watering Plan 2020-21. 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.
Providing water for the environment is only one way of protecting and improving rivers and wetlands. Fencing and revegetation, erosion control, pest control, returning logs to rivers (re-snagging) for fish and bug habitat, and installation of fishways to allow fish to pass through dams and weirs also help. Find out more about river health, water for the environment and monitoring activities at www.gbcma.vic.gov.au
To check flows in the Lower Goulburn, view the hydrograph on Goulburn Broken CMA’s website.