A long-running legal battle around native bush in Auckland’s Titirangi has finally reached a conclusion, with three and a half hectares to be cleared to make room for a new water treatment plant.

Titirangi Protection Group’s chair Megan Fitter said there’s a feeling of “disbelief” in the settlement, having spent the last seven years fighting for the bush to remain.

“For us, it’s a disappointment, but we do accept that the efforts we’ve gone to have meant that the situation is not as bad as it could have been if we’d just rolled over at the very beginning,” she said.

The proposed treatment plant site is contaminated with Phytophthora agathidicida, the pathogen that causes kauri dieback disease.

Tree Council secretary Mels Barton said this would have been an “existential threat” to kauri trees in that catchment.

“Basically, they would all have died because [of] the volume of the pathogen that would have been exposed,” she said.

Fitter said some locals have expressed concerns about the impact heavy vehicles may have on flood-damaged roads that have only just been repaired.

“We just think having a lot of construction around will impact locally, and Watercare have assured us there’s measures around that,” she said.

Watercare’s head of strategy and planning Priyan Perera said with any large infrastructure project there would be “significant truck movements.”

“Our planning is evolved to ensure that we minimise the movements outside of the neighbourhood, but in doing so we do create some local impact,” he said.

Perera described the current plant as an “asset” that has been part of Auckland infrastructure for nearly 100 years and is critical for the supply of drinking water.

“As you can imagine as things get old, and things get a little bit tired, [it] is time to renew that asset,” he said.

Perera said Watercare understands the concerns and has spent a lot of time “listening” to needs of the community.

“We do our best to provide as much information as we can and use that information to inform the community about where we’re headed,” he said.

The ecological compensation package has also been increased from the $5m over 10 years originally proposed by Watercare, to $8.2m over 25 years.

It’s to recognise, as you say, that we’re having an impact. In recognition of that impact, we’ll be investing and making sure we do our best to protect the environment around us,” Perera said.

The project is now in it’s design stage and due to be completed four years behind schedule in 2033.