Tackling toxic algae bloom at Lake Tūtira

10:58 am on 17 April 2018

Decades of failed attempts to clean up two contaminated lakes in Hawke's Bay may be coming to an end as hapū and officials work together on a new $3.5 million project.

No caption

Photo: Supplied

Lake Tūtira and its smaller sister Lake Waikōpiro are nestled between Napier and Wairoa. They were once renowned trout fishing and eeling spots until they became filled with toxic algae blooms.

A new project called Te Waiū o Tūtira, or milk of the Tūtira, will offer a coordinated approach between the hapū owners of the lake, local and central government, and Tūtira residents.

The government's Freshwater Improvement Fund will contribute $1.5m, with $3.5m spent in total over four years to create a catchment plan, plant more trees, install sediment traps and establish farm management plans.

Lake Tūtira is considered taonga by local hapū. The lake bed is owned by the Maungaharuru-Tangitū Trust and its general manager Shayne Walker is confident things will be different this time around.

Maungaharuru-Tangitū Trust general manager Shayne Walker said the project was all about working together.

"Just like the song Tūtira Mai Ngā Iwi which was written on its shores," he said.

The hapū had only been opposed to chemically treating the sediment, which had been raised as a possible solution, he said.

"We prefer to treat the lake naturally and at the rate of how things are going I'm confident the lake will be swimmable and eels can be harvested again in five years' time," he said.

Hawke's Bay Regional Council water scientist Dr Andy Hicks was also confident results would finally be seen, as Te Waiū o Tūtira was the first time a coordinated approach would be brought to the lakes.

An air curtain installed in Lake Waikōpiro in September was producing mixed results, but addressing sediment and nutrient flows into the lake would have the greatest effect in the longer term, he said.

Fish and Game Hawke's Bay was also hopeful. It released only half the trout it normally would into Lake Tūtira this year, because of fears they would die.

Regional manager Mark Venman said more trees were planted instead, and he was confident the new project would bring better results.

In the meantime, Dr Andy Hicks said a trial using the air curtain only every other week was bringing positive results as it appeared to have a better impact on keeping the many different types of algae in the lake in balance.

If the air curtain proved successful then another, bigger, air curtain could be installed in Lake Tūtira next winter, he said.

Get the RNZ app

for ad-free news and current affairs