Concerns raised about toxic algal blooms at Lake Omapere

Far North Mayor John Carter, Ōmāpere Taraire E Rangihamama X3A Ahuwhenua Trust spokeswoman Rachel Witana, Minister Damien O'Connor, and Labour MP Willow-Jean Prime. Photo / supplied

Concerns have been raised about toxic algal blooms at Lake Ōmāpere, which is being set up as an emergency water source for Kaikohe residents in drought-stricken Northland.

The Far North District Council said Northland District Health Board is concerned about algal blooms at the lake and has yet to approve it as a water source to boost Kaikohe's dwindling supply.

Up to $2 million has been allocated from the Provincial Growth Fund to set up temporary water supplies in Kaikohe and Kaitaia.

On Thursday Agriculture Minister Damien O'Connor met with Far North Mayor John Carter, Labour MP Willow-Jean Prime, local iwi, Civil Defence, and Fire and Emergency NZ staff to review the effects of the drought and the response to Northland's water crisis.

The group also surveyed the emergency pipe and equipment that's being set up at the lake which will be pumped to the towns' water treatment facilities before being piped to households.

A council spokesman said though it expects to be able to draw water from the lake this weekend, it won't immediately be available for drinking purposes.

"The NDHB is concerned about the lake's susceptibility to algal blooms," he said.

"It has asked us to provide more barriers in our treatment process against cyanobacteria toxins. We have engaged specialists to reconfigure our treatment process and are finalising a design. We are making good progress on this but can't say at this stage when this work will be completed."

Far North Mayor John Carter and Agriculture Minister Damien O'Connor discuss the drought at Lake Omapere. Photo / supplied

Water from Lake Ōmāpere will supplement Wairoro Stream, which provides most of Kaikohe's water and is at critically low levels. The council plans to take up to 1500 cubic metres of water a day from the lake for 100 days.

It is working with Lake Ōmāpere Trust and Ōmāpere Taraire E Rangihamama X3A Ahuwhenua Trust, who have given permission to pipe water over its land to Taraire Hills water treatment plant.

A 3km pipe on loan from Refining NZ's Marsden Point facility is in place, power generators have been deployed and a water pump was being set up at the site yesterday. Lake Ōmāpere is Northland's largest lake, but its shallowness - 1.8m at its deepest point - makes it susceptible to algal blooms.

The last toxic bloom was in February 2018 which threatened aquatic life and the health of people using the water.

The 3km pipe that is taking water from Lake Omapere to supply Kaikohe residents with drinking water. Photo / supplied

The bloom, caused by cyanobacteria that thrive in warm conditions, turned the water a lurid green colour. The NRC monitors algal levels in the lake from November to April.

Carter said the remaining obstacle to supplying potable water from Lake Ōmāpere is its susceptibility to toxic algal blooms.

"We are reconfiguring our Taraire Hills Water Treatment Plant, so it can treat the lake water effectively," he said.

"We are also working closely with Northland District Health Board, which needs to approve the lake as a temporary water source."

Carter thanked all parties involved in delivering the solution for Kaikohe.

Ōmāpere Taraire E Rangihamama X3A Ahuwhenua Trust spokeswoman Rachel Witana said the water crisis has brought the need for government agencies to engage with hapū into sharp focus.

The treaty requires that government agencies and hapū operate as an equal partnership, she said.

"The challenge was never around providing access or providing water. The challenges were around the use of our natural resources and treaty obligations."

However, "The objective of the hapū is the same as the government agencies; to ensure that people have access to clean drinking water," she said.

Witana said it was essential that New Zealand standards around the quality of water are followed when taking water from the lake.

Because of the natural resources and taonga species, the wellbeing of the lake and water quality are high priorities for hapū, she said.

"It's not only about the wellbeing of the lake, it's also about the wellbeing of our people."

NDHB was approached for comment, but did not respond before deadline.