Environmental water release for the Tarago River
Melbourne Water, in partnership with the Victorian Environmental Water Holder (VEWH), will commence an environmental water release to the lower Tarago River system on 1 May 2017.
Otherwise known as an “autumn fresh”, the release will help provide a spawning trigger for downstream migration of Australian Grayling and will enhance the river’s health.
Why is this needed?
A drier-than-average late summer and autumn means that the Tarago River has not received sufficient flows to support the grayling population.
As well as triggering spawning of Australian Grayling, a threatened native fish species, the release is designed to flush fine sediment and organic material from the river bed and maintain habitat for bugs and fish life.
Part of Melbourne Water’s environmental flows program focusses on supporting juvenile Australian Grayling migration and spawning. Australian Grayling spawn in the freshwater reaches of the system before the eggs and larvae drift out to sea.
The juvenile fish spend approximately six months in the sea before they migrate upstream. Other species expected to benefit from the increased environmental flows include the platypus and the regionally significant River Blackfish.
Environmental water improves the health of rivers and increases recreational opportunities for Victorians living beside or visiting waterways
What does this involve?
Melbourne Water will release up to 700 million litres of water over a two week period from Tarago Reservoir into the Tarago River system, to improve water flow along the river and into the lower Bunyip River.
During the release, river levels between the Tarago Reservoir and the estuary may be up to 30-40 cm higher, which is within the river’s usual level of variance. The peak will be at Drouin West from 6 to 9 May and at Iona around 7 to 10 May.
Detailed planning and close monitoring of water levels will be undertaken during the entire release period. Melbourne Water is working with the VEWH and other stakeholders to monitor the response of the river and aquatic life closely following the event to inform future releases.
The release is in line with the VEWH’s Seasonal Watering Plan 2016-17.