Design work on the new protozoa barriers for both Ranfurly and Patearoa water supplies is underway.

The upgrades to the water treatment plants were required to be completed by the end of 2025 under directions from Taumata Arowai.

Central Otago District Council capital projects programme manager Patrick Keenan told the Maniototo Community Board on Thursday that some specialised materials may need to come from overseas, which could cause delays in the timeline.

Naseby and Ranfurly have both been on urgent water restrictions this summer, after heavy rain caused two separate incidents affecting both of its supplies.

The new $3 million treatment solutions would solve both Ranfurly and Patearoa’s water turbidity issues they were prone to.

Patrick told the meeting tenders for the work closed in May but there had already been two site visits organised with potential contractors to see what needed to be done.

The Ranfurly and Patearoa treatment plants sourced their water from ‘surface water sources’ — the East Ewe Burn and Sowburn River. 

All of the projects have been in the Long Term Plan (LTP) for some time, and he said with the new changes being implemented, they were taking a more pragmatic approach to the design.

“And it won’t be as expensive as we first thought they would be.”

Protozoa barriers mitigate parasites, such as cryptosporidium, entering the water supply system. 

The installation of those barriers was part of a New Zealand-wide strategy to improve water safety and prevent waterborne illnesses which could cause significant health issues. 

When protozoa was effectively removed or inactivated, the risk of outbreaks such as the one in Queenstown in September 2023, was substantially reduced.

Patrick said they had been running trials with treatment filters and worked out they could add onto the existing plant rather than build a whole new one.

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