Blue-green algae monitoring results

Before you jump in know what you're getting in to

The Bay of Plenty Regional Council monitors the lakes for algal blooms.

We monitor 13 sites for blue-green algae spread across four lakes; Lake Rotorua, Lake Rotoiti, Lake Rotoehu and Lake Ōkaro (we also monitor Lake Tarawera if required). These sites have been selected because they’ve been known to bloom in the past, and because they’re regularly used by the public for recreational activities, it’s important to ensure the water is safe.  

Sites are given an alert level status based on the number of bacteria found, and these results help us decide whether a health warning should be put in place.

Yet, water sampling is only a snapshot from a particular time and place. Water quality can change quickly especially at the start of an algae bloom or after heavy rain when contaminants can be washed off the land and into waterways.

People should avoid swimming for at least two to three days after heavy or prolonged rain, even for sites that usually have good water quality. If you can’t see your toes in calf deep water, or lake water looks green and cloudy, it is best to wait until the water clears before taking a dip.

People should also avoid swimming near potential sources of contamination such as flocks of birds.

Water Quality

Details of Recent Water Quality Tests

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A health warning is in place for Lake Rotoehu. 

A health warning has been put int place for Lake Rotoehu as routine monitoring results provided by the Bay of Plenty Regional Council have confirmed blooms of potentially toxic blue-green algae in this lake.

Contact with water affected by blooms of blue-green algae can cause asthma and hayfever attacks in some individuals. Contact with the blue-green algae can also cause skin rashes, stomach upsets, and in some cases neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.

Algae may also accumulate and form scum collections along the shoreline of the lakes. It is especially important that parents ensure that children avoid contact with both the water and any algal scum along the shoreline as this may be toxic. It is also advisable to keep pets and livestock out of the water and off the shoreline.

Check the Toi Te Ora health warnings page for further information or the site details for sampling history.

Kaituna RiverTrout Pool000
ŌkaroBoat Ramp000
RotoehuKennedy Bay505
RotoitiOkawa Bay000
Okere Arm000
Te Weta000
Holdens Bay000
Ohau Channel000

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