Kerikeri water supply down to one stream
The Far North District Council is supplying its Kerikeri water treatment plant only from Puketo¯tara Stream while tests for algal bloom toxins continue on its second source, Lake Waingaro.
The lake, owned and operated as a reservoir by the Kerikeri Irrigation Company, normally supplies about 70 per cent of the raw water that goes to the treatment plant, the Puketo¯tara Stream providing the rest. The council stopped drawing from the lake last Monday, however, when the company reported the presence of cyanobacteria (commonly known as blue-green algae).
FNDC general manager — infrastructure and asset management Andy Finch said algal blooms often developed in rivers and lakes during warm weather, and could produce cyanotoxins, which were harmful to human and animal health. Normal water treatment processes were not effective in neutralising the toxins.
“We have tested water at the Kerikeri treatment plant for cyanotoxins, and have confirmed it is safe to drink,” he said on Thursday.
“We will continue to take water only from Puketo¯tara Stream for another week, and conduct further tests on the lake water to be absolutely sure no toxins are present. Only then will we resume taking from Lake Waingaro.”
Regular tests for cyanotoxins would continue over summer to ensure the water was safe.
The Kerikeri Irrigation Company, which is continuing to supply about 500 customers from the lake for irrigation purposes only, said it had notified its customers of the algal bloom, and would keep them updated via its website. The particular strain of algae detected was capable of producing toxin, but no toxin had been detected at that stage.
A council spokesman said Puketo¯tara Stream provided enough water to meet Kerikeri’s current consumption, but would not be able to do so over peak summer demand. Restrictions would be implemented if the lake remained unusable.
Northland Regional Council has warned users downstream of the reservoir to avoid using the water for drinking by people or stock until cyanobacteria levels fell to “acceptable” levels.
Updates would be posted on the NRC website as soon as they became available.