Conserve water notices issued for Naseby, Omakau and Ranfurly after the weekend’s heavy rain were still in place on Monday evening (October 6), with a Central Otago District Council (CODC) contractor working to fix the issues.

The notices were first issued for Naseby and Omakau on Sunday afternoon, and extended to Ranfurly on Monday morning, after sediment-laden water from swollen waterways made it difficult for treatment plants to produce clean drinking water. 

By Monday afternoon, CODC said water quality was beginning to improve and its contractor was “working hard to restore normal operations”.  

Residents were urged to reduce water use as much as possible to preserve stored supplies, with CODC stressing “every drop helps”.

CODC water services operations manager Andrew Watson said rainfall events often stirred up sediment in surface water sources, increasing turbidity.

“This can overwhelm existing treatment systems, making it difficult to produce clean water that meets drinking water standards,” he said.

“To protect public health and maintain supply, council may need to rely on stored water and issue ‘Conserve Water Notices’ to help extend those reserves while treatment systems recover.”

Andrew said a programme of infrastructure upgrades is under way to improve resilience.

For Omakau, reservoir capacity is being tripled, with 12 new tanks due to be commissioned soon, and planning is underway for a future treatment plant upgrade.

Down the road in Ranfurly and Patearoa, a $4.2M treatment plant upgrade to include cartridge filtration and UV barriers has been budgeted for to better handle dirty water during high-sediment events.

“It’s important to note that while these improvements will significantly enhance water safety, they won’t eliminate all water quality issues,” Andrew said.

“During severe weather events, council may still need to issue ‘Conserve Water Notices’ or ‘Boil Water Notices’ as a precaution.”

Meanwhile in Naseby, the town’s supply already has UV and chlorine treatment in place but remains prone to high turbidity.

“Council has carried out significant investigations into alternative water sources for all Maniototo supplies,” Andrew said. 

“The current focus is on optimising the operational performance of the treatment plant to ensure it is functioning as effectively as possible.” 

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