A back-up water supply from Lake Ōmāpere for drought-hit Kaikohe has finally been approved for use — but a lingering bad smell means treated lake water will only be piped to people's homes in an emergency.
Kaikohe has the Far North's worst water shortage and, along with Kawakawa-Moerewa and Rawene, is still under level 4 restrictions banning all but essential use.
The town normally relies on the Wairoro Stream for most of its water.
An agreement with two iwi groups — Lake Ōmāpere Trust and Ōmāpere Taraire E Rangihamama X3A Ahuwhenua Trust — plus cash from the Provincial Growth Fund (PGF) allowed the Far North District Council to set up an alternative supply by pumping water from the lake to its Taraire Hills water treatment plant.
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Mayor John Carter said the ''relatively straightforward'' job of piping lake water 2.8km to the treatment plant was completed in March.
However, making sure the water met national drinking water standards had been far more complicated.
Council staff and alliance partner Far North Waters had worked with the Northland District Health Board and water treatment consultants to modify the Taraire Hills plant so it could remove toxin-producing bacteria if the lake was hit by another algal bloom.
That included creating a large settlement reservoir allowing material that could harbour the bacteria to settle out.
The health board had now given the green light to use water from the lake, Carter said.
However, the council would only supply treated lake water if its other sources failed.
"We've successfully removed the danger of cyanobacteria-related toxins but we can't remove all of the unpleasant odour and taste of the lake water. While the water is safe to drink we will only use it in an emergency to avoid taps running dry."
Carter said the Wairoro Stream was still running below consented levels but its flow had stabilised and should increase as winter approached.
"Kaikohe residents and businesses have done a fantastic job of reducing their water consumption by 25 per cent and more since mid-February. I encourage people to continue making these savings to avoid the need to use the lake as a water supply."
Carter said he was grateful to the iwi trusts for making the lake available and to Regional Economic Development Minister Shane Jones for allocating $2 million for temporary water supplies in Kaikohe and Kaitaia.
Another $30m has been allocated by the PGF to investigate water storage sites in the Far North, Mid-North and Kaipara.
A site for a water storage dam near Kaikohe has been identified and, depending on post-Covid-19 timeframes, construction was expected to start in summer.
The plan entails building a series of small-scale reservoirs and a distribution pipeline, similar to the Kerikeri irrigation system built as a government project in the 1980s.