Air curtain improving water quality

Pressurised air is being pumped through a 50-metre pipe tethered close to the bottom of lake and across the deepest part, creating an air curtain. It increases oxygen levels at all depths throughout the lake by creating a circulation current, much like bubblers in a fish aquarium.

HBRC Water Quality and Ecology Scientist Dr Andy Hicks says oxygen levels are being maintained at a high level throughout Waikōpiro, and pH is at a healthy level.

“In contrast, there is very little oxygen in the bottom waters of nearby Tūtira Lake, and pH in the surface water is very high,” says Dr Hicks.

“Waikōpiro is warm at all depths, but the temperature remains cool in the bottom water of Tūtira.”

Dr Hicks says the Ceratium bloom in Waikōpiro does not appear to have been disrupted by the air curtain, however the potentially toxic cyanobacteria has not yet been observed. Meanwhile, Cyanobacteria has been observed in Tūtira, although not yet at full bloom levels.

Together, Hawke’s Bay Regional Council and Maungaharuru-Tangitū Trust aim to improve water quality and habitats in Waikōpiro and Tūtira Lakes.

7 December 2017

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