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Regional Council continues to monitor Lake Tarawera

Friday, 30 January 2015 10:00 a.m.

Earlier this month Bay of Plenty Regional Council confirmed the presence of blue-green algae in Lake Tarawera and advised people to be careful when using the lake. Swimming is not advised if the water appears discoloured and drinking the water is not advised at any time without appropriate treatment – unfortunately boiling the water will not reduce the hazard posed by blue-green algae.

Council is monitoring the popular lake closely, particularly in the Te Rata Bay, Te Puna Bay and Hot Water Beach areas, to make sure the algae do not pose any serious health risks to lake users.

“The tests that confirmed blue-green algae in Lake Tarawera gave some cause for concern,” Council Science Manager Rob Donald said. “As a consequence we are monitoring the lake regularly and will continue to do so until the levels of algae subside,”

Members of the public are asked to report any sightings of the algae to the council.

The lake is currently at ‘Amber alert’ mode which means that the bio-volume of all blue-green algae is between 0.5 and 10mm³ per litre.  Under such conditions, the water is likely to appear discoloured, and there may be signs of scum from algae floating on the surface. Lake Tarawera has recently had blue-green algae bio-volumes of up to 9mm³ per litre, putting it in the upper level of the amber mode.

Blue-green algae are found naturally in lakes and rivers throughout the country, but populations can increase dramatically under certain conditions. A fair proportion of the groundwater and nutrients entering Lake Tarawera is from its seven surrounding lakes; Ōkāreka, Ōkaro, Ōkataina, Rerewhakaaitu, Rotokakahi, Rotomahana and Tikitapu.

“The nutrients that are entering the lake coupled with warmer weather and still water has most likely contributed to the algal blooms at Lake Tarawera,” Mr Donald said.

The algae were discovered after members of the public reported sightings of discolouration in the Te Rata Bay area to Regional Council staff.  “It is still a very busy time out on the lakes and we are calling on the public to phone Bay of Plenty Regional Council on 0800 884 880 if the water looks unusually green in colour and has an odd odour, so we are aware of any further algal blooms,” Mr Donald said.

Lake Tarawera