Environmental water release - Tarago River system

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Environmental water release - Tarago River system
Tuesday 14 April 2015 - Melbourne Water



The autumn fresh release on 15 April 2015 will help provide a spawning trigger for downstream migration of Australian Grayling, benefit the platypus, River Blackfish and flush fine sediment from the river bed.

When will peak levels occur?

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 20 - 23 April 2015 and at Iona around 21 - 24 April 2015.

Why is this needed?

Due to a drier-than-average late summer and autumn the Tarago River has not received sufficient flows to support the Australian Grayling population. Recent research has shown that the autumn fresh flow has triggered the successful migration and spawning of the Australian Grayling in the Tarago River system.

As well as triggering spawning of the threatened native fish species, the release is designed to flush fine sediment and organic material from the river bedand maintain habitat for bugs and fish life.

Part of Melbourne Water’s environmental flows program focusses on supporting juvenile Australian Grayling migration and spawning. These fish 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.

What does this involve?

We will release up to 700 million litres of water over a two week period from Tarago Reservoir into the Tarago River system. This will improve water flow along Tarago River and into the lower Bunyip River.

We will be acoustically monitoring the response of adult grayling and platypus to the flow release. The information gathered through this monitoring will help us to further refine future environmental water releases to provide optimal outcomes.

Detailed planning and close monitoring of water levels will be undertaken during the entire release period.

We are working with the Victorian Environmental Water Holder and other stakeholders to monitor the response of the river and aquatic life closely following the event to inform future releases. The VEWH prioritised this water release as part of its Seasonal Watering Plan 2014-15 ,which aims to improve river and wetland health across the State.

For further information on this project, please call Sarah Gaskill, Senior Environmental Water Planner, on (03) 9679 7045.
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