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Colac water supply upgrade

Barwon Water is upgrading Colac’s water supply system

The city is scheduled be connected to the greater Geelong system by mid-2017, providing greatly increased supply diversity and security.

The $19.3 million upgrade will cater for forecast growth and reduce the threat of reduced catchment inflows in dry years. It will also offer protection against the risk of bushfires, land slips and failure of the existing 28-kilometre supply pipeline from the West Gellibrand and Olangolah reservoirs in the Otway Ranges.



In 2012, Barwon Water identified the need to boost Colac’s water supply capacity based on predicted growth, climate change and potential risks to existing infrastructure.

Barwon Water’s Board agreed to connect Colac to the Wurdee Boluc channel, which carries water from the West Barwon Reservoir in the Otways to the Geelong supply network.

The decision followed detailed analysis of six shortlisted options, feedback from extensive community consultation and a unanimous recommendation by the Colac Community Reference Group.

The upgrade will ensure water security by providing access the West Barwon Reservoir via Wurdee Boluc channel and, if required, the Barwon Downs borefield.

Water will be transferred from the channel via an existing pipeline south of Murroon to a storage basin to be built at the Barwon Downs pre-treatment plant. A new pipeline will transfer water to the existing Colac pipeline, six kilometres south of the Colac water treatment plant. The new pipeline will pass through Barwon Downs, Gerangamete and Yeodene.


Colac’s water supply

Colac’s drinking water is currently sourced from the West Gellibrand and Olangolah reservoirs, both on the Gellibrand River in the Otway Ranges.

These relatively small reservoirs fill quickly when it rains but also empty quickly during drought.

An additional 700 to 1,000 million litres a year is required to secure the district's supply.

When full, the Colac system holds about 8 months’ worth of supply. By comparison, Geelong's combined surface storages have sufficient water for around 3 years, plus additional capacity via two underground aquifers and the Victorian water grid via Melbourne.


Community and stakeholder engagement

In 2013, Barwon Water conducted an extensive stakeholder and community engagement program around six shortlisted supply options.

Engagement included a community survey, several information kiosks and briefing sessions and the formation of a Colac Community Reference Group.

The group met several times to consider the potential social, environmental and financial impacts of the options and in June 2013, endorsed Barwon Water’s proposal to connect Colac to the Geelong supply system via the Wurdee Boluc channel.

We will continue to work with local landowners and the Colac community as work begins and throughout construction.


News and updates

1 December 2016: Colac pipline construction begins
31 August 2016: Colac pipeline contract awarded to local company
10 December 2015: Colac water supply upgrade fast-tracked