Candowie Upgrade Project
Westernport Water is upgrading the Candowie Reservoir, by raising the full supply level three meters. This will double water capacity from 2,263 ML to 4,463 ML.
Candowie Reservoir is fed from the Tennent Creek catchment and was the sole water supply to our mainland and Phillip Island community within Bass Coast since the reservoir was constructed in 1964. Storage capacity was first increased in 1978 and again in 1982, but our water supply vulnerability in the face of growing population and drought periods was exposed in 2006/2007, when the dam level fell to just 7%. The drought necessitated emergency measures to access more water, and it was necessary to impose water restrictions.
Candowie Upgrade project is a key component in our Water Supply Demand Strategy and features in the Central Region Sustainable Water Strategy which requires Water Corporations to provide adequate water supply to 2055.
Increasing the capacity will enable Westernport Water to further improve water supply, as well as enable the Corporation to draw the full water entitlement from the Tennent Creek catchment.
The additional reservoir volume will provide capacity to store water from the Bass River and Corinella Bore field that were installed after the 2007 drought. This enables the collection of locally available low coast water and reduces exposure to water restrictions.
Westernport Water will also upgrade existing infrastructure at the reservoir to comply with current ANCOLD dam safety standards, to cope with a '1 in 100,000 year' flood event and improve earthquake safety and dam surveillance.
In addition, Westernport Water will have access to Melbourne’s water supply system via a connection to the Metropolitan Pool Transfer pipeline on the Bass Flats for use in extreme drought conditions.
The Detailed Design of the Reservoir Upgrade Works was completed by dam specialist engineers Entura, a consulting arm of Hydro Tasmania.
All project approvals are in place.
Principal elements of the work are to;
raise and extend the width of the dam wall,
raise the Outlet Tower and replace the access walkway,
construct a new Wash Water Holding Tank, and
raise the spillway crest and adjacent spillway walls.
The construction contract has been awarded to Geotech Pty Ltd who are civil contractors experienced in dam infrastructure projects. Works commenced in September 2012 and are scheduled for completion in mid-2013.
To accommodate the new full supply level, it will be necessary to raises the Grantville Glen Alvie road by one metre where it passes over Tennent Creek. The road works contract has been awarded to Goldsmith Civil Engineering Leongatha and works are expected to begin in December 2012.
Click on the images below to download fact sheets regarding progress of the Candowie Upgrade as at March 2013
'Water Supply Retrospective' (189 KB) - A history of the Candowie Reservoir