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15 June 2020

Coliban Water is preparing to drain and inspect a key piece of the Castlemaine water supply network in coming weeks.

Kalimna Basin is an enclosed clear water storage that receives treated water from the Castlemaine Water Treatment Plant (WTP) and then supplies the network via gravity when the basin levels are full.

Manager Customer Operations Steve Dunlop said the major inspection hasn’t been undertaken at the site since 2011.

“We have an ongoing program of cleaning and maintaining our storages, but a major inspection such as this is only required every decade.

“This proactive work is about ensuring our assets are in the best condition possible, and continuing to provide safe, clean drinking water to our customers,” Mr Dunlop said.

Three days of testing will take place between Tuesday 23 and Thursday 25 June 2020, which will ensure the basin can be isolated from the network without impacting customers.

If successful, the draining, clean and inspection will take place between Thursday 2 and Friday 10 July 2020. The basin will be drained and taken offline to undertake a major condition assessment and clean.

During the works, water will be supplied direct to the Castlemaine supply network from the plant, bypassing the basin.

“In addition to the cleaning and inspections we are undertaking, we are also installing a new mixer in the basin.  The mixer will ensure water age and disinfection levels are very consistent throughout the entire basin, which improves the uniformity of water that is delivered to our customers throughout the network.

“As part of the treatment changes we made to the Castlemaine water supply network over 12 months ago, we have also made significant changes in the monitoring and daily operations of our network.

“This has been to ensure we minimise the impact to customers of any taste or smell associated with the water supply, and ensure disinfection levels are maintained throughout the network.  One of the key changes made is ensuring the basin fills outside of peak times seen in the morning and evenings each day.

“These works that will be undertaken will not interrupt water supply, nor change our treatment process, but some customers may notice a change to the taste and smell of the water, with the water supply coming directly from the treatment plant during this time, along with the possibility of some minor fluctuations in water pressure.

“This will return to normal once the project is complete on Friday 10 July 2020, weather dependent,” Mr Dunlop said.

For further information, please call our Customer Support Team on 1300 363 200 or visit

Last updated on 15 Jun 2020
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