Drought-stricken Kaikohe finally has a new back-up water supply, thanks to the government's Provincial Growth Fund and two iwi trusts.

The Northland District Health Board has signed-off new treatment measures for water from Lake Ōmāpere, to be taken under agreements the council has reached with the Lake Ōmāpere and Ōmāpere Taraire E Rangihamama X3A Ahuwhenua trusts.

Mayor John Carter the council, with the support of the PGF and the trusts, had spent the last two months developing infrastructure to allow the lake to be used as a back-up water supply. That had involved installing extensive, extra treatment infrastructure at the Taraire Hills water treatment plant to remove toxin-producing bacteria from the water.

In the past the lake had suffered from algal blooms that could produce harmful toxins.

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Piping water to the treatment plant had been a relatively straightforward job, and was completed in March, but ensuring that the water met NZ Drinking Water Standards had been a far more complex problem to solve.

"Our staff and our alliance partner, Far North Waters, have worked closely with the Northland District Health Board and water treatment consultants to modify the water treatment plant so we can be sure it will remove toxin-producing bacteria if an algal bloom reoccurs in the lake," he said.

"This was achieved by creating a large settlement reservoir that allows material that may harbour the toxin-producing bacteria to settle out and be removed from the system. The DHB agrees that this will ensure the safety of the supply, and it has now given us the green light to use water from the lake."

The council would only supply treated water from the lake if its existing sources failed, however.

"We have successfully removed the danger of cyanobacteria-related toxins, but we cannot remove all of the unpleasant odour and taste of the lake water. While it is safe to drink, we will only use it in an emergency to avoid taps running dry," he said.

Meanwhile the town's primary water source, the Wairoro Stream, was still running below consented levels, but flows had stabilised and were expected to increase gradually 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 to make these savings to avoid the need to use the lake as a water supply," Carter added.

He was grateful to the iwi trusts for making the lake available as a temporary water supply, however. He also thanked Regional Economic Development Minister Shane Jones, for allocating $2 million from the PGF for temporary water supplies in Kaikohe and Kaitaia as part of the Government's response to the drought.

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"The co-operation between the government, the council and the trusts, who are the kaitiaki of Lake Ōmāpere, has delivered a good outcome for the Kaikohe community," he said.

Up to $30 million had been provided through the PGF to investigate potential water storage sites in the Far North, Mid North and Kaipara. The council was also working with the Northland Regional Council and others in the development of reservoirs in the Kaikohe area. An initial site near Kaikohe has been identified, and, depending on post-Covid-19 timeframes, construction is expected to get under way next summer. Further sites will be explored as the project evolves.

The plan is to build a series of small-scale reservoirs with a distribution pipeline.