Trees

Flows timed to improve Goulburn River bank-stabilising plant growth

Wednesday 19 September, 2018
Water for the environment will help critical bank-stabilising plants along the lower Goulburn River re-establish and grow.

At a recent Murray Darling Association National Conference, concerns were raised about the impact on bank vegetation of the higher-than-usual water that was delivered down the Goulburn River between January and May.

Greater Shepparton City Council moved a motion at the conference calling for an investigation in to the environmental impacts of running commercial water down the Goulburn River during summer.  The motion stated that "the river was artificially held high in these summer months due to the transfer of water to other irrigation areas following purchasing of this water … destroying all the ground cover that had benefited from an environmental flow during spring 2017.”

Goulburn Broken CMA CEO Chris Norman said inter-valley transfers - water traded between different systems, such as between the Goulburn and the Murray - had started earlier than usual this irrigation season.

“To minimise the effects on the river’s banks and vegetation caused by a constant flow, we’ve worked closely with Goulburn-Murray Water and the MDBA to ensure that the inter-valley transfers are delivered along the Goulburn River as a variable flow,” Mr Norman said.

From Monday September 24 water for the environment will be released from Goulburn Weir and will “top up” inter-valley transfer deliveries, which are currently between 500ML/day and 3000ML/day. This extra water could see river flows peak around 8,500 ML/day (a river height of about 4m) around Friday October 5. This is well below minor flood level.

The actual amount and mix of Victorian and Commonwealth water for the environment used will depend on downstream demand and channel capacity. Run-off and inflows from tributaries after any rain may also contribute.

The flow will take about four days to reach McCoy’s Bridge from Shepparton. As the water makes its way down the Murray River it will also benefit downstream wetlands and communities.

“This flow will improve water quality and encourage plants in the Goulburn River and on the lower and mid-banks to grow and spread, which as well as helping the banks, will provide food and shelter for wildlife, fish and water bugs during spring and summer,” Mr Norman said. 

“After the great results we’ve seen in recent years in the Goulburn River thanks to water for the environment, such as record numbers of silver perch recorded last year and significant increases in other threatened native fish, including trout cod, it’s important we maintain water quality, particularly if it stays dry. Good water quality reduces the cost of treating water for consumption by communities and is better for stock and crops, too.”

The proposed higher flows will coincide with school holidays when many people will be out on the rivers, camping, boating and fishing.

As river systems are now highly modified, environmental water managers do not aim to return rivers to ‘natural’; rather they aim to time delivery to protect specific sites and species at key times in the breeding and growing cycle.

Water for the environment is also subject to the same conditions in regards to allocations and carryover as water for irrigators and other users.

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 2018-19. 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 these activities here.