Timely boost for Goulburn River bank vegetation

Friday 2 October, 2020
Water for the environment is being delivered along the lower Goulburn River to encourage the seed and sediment distributed on the river’s lower and mid-banks during winter to grow and spread.

As part of the Goulburn flows strategy, environmental watering will be provided to mimic the naturally higher flows that would have occurred at this time of the year before dams, weirs and channels were built.

Carefully managed environmental watering plays a vital role in allowing seed and other wildlife to grow – creating a healthier river for all. Continuing to limit flows during summer will ensure the effort made through environmental watering is not lost. 

“Healthy bank vegetation provides valuable habitat for native fish, water bugs and other wildlife to feed, breed and shelter,” Goulburn Broken CMA’s Simon Casanelia said.

“It’s important that we continue to focus on bank health and water quality so the improvements in vegetation and threatened fish numbers we’ve seen in response to spring environmental flows delivered over the past decade are not lost. Good water quality reduces the cost of treating water for use by communities and is better for stock and crops, too.”

Since Wednesday September 30 water for the environment has been released from Goulburn Weir. The releases will gradually increase to about 8000 megalitres (ML) a day by October 9 (a river height of 5m at Shepparton) and then reduce back to current levels, about 900 megalitres a day (2.7m at Shepparton), by October 29. 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 the flow may be reduced.

“Last year, due to dry conditions, we used water for the environment in July and September to help promote the growth of bank vegetation and provide refuge for native fish,” Goulburn Broken CMA’s Simon Casanelia said.

“This year we were fortunate to have good rain and tributary inflows during autumn and winter, which saw flows of up to 12,000 ML (6.5m) and 16,000 ML/day (7.65m), so we did not need to deliver our annual July environmental flow. With those higher flows depositing plenty of seed and sediment on the banks, delivering the annual September environmental flow will allow us build on nature’s good work. The environmental flow will also contain organic material, which helps drive the food web.”

Encouraging bank-stabilising plant growth also goes some way towards rehabilitating banks affected by record high summer flows in recent years. These high summer flows were due to the transfer of inter-valley trade water to the Murray River. The Victorian Government recently announced an interim operating rule for this season that aims to not exceed a maximum of 40 gigalitres a month for the transfer of inter-valley trade water during summer and early autumn to protect the lower Goulburn River environment.

The use of water for the environment during spring will increase flows at a time of year that is beneficial to the environment. More than 90 per cent of the environmental flow will reach the Murray River and will provide multiple environmental, cultural, community and recreational benefits as it makes its way to the mouth of the Murray.                                                                                              

The response of vegetation to the water delivery, as well as any silver and golden perch spawning, will be measured in October as part of the Commonwealth Environmental Water Office’s Monitoring Evaluation and Research (Flow-MER) project. A proposed late spring environmental flow will build on any native fish spawning and trigger fish movement between the Goulburn and Murray rivers and their tributaries.

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 takes 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  (updated weekly).