An environmental battle is playing out in Auckland's Waitakere Ranges over plans to clear native bush to provide clean drinking water.
Emotions are running high with claims the project will spread kauri dieback disease, affect the habitat of a new species of flightless wasp and make a mockery of a climate change emergency declared by Auckland Council.
Just outside Titirangi in the native bush clad hills of the Waitakere Ranges lies the Huia treatment plant which has been treating water from local dams for nearly 100 years.
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The time has come, says Watercare, to replace the ageing plant and build two water storage holding tanks, or reservoirs, with more advanced treatment processes to ensure the resilience of the city's drinking water.
Huia was chosen from a shortlist of four sites after the council-owned water company got burnt in 2017 with a proposal to take up to 18 homes and rural properties in the close knit community of Oratia.
Oratia was a disaster, says a prominent environmentalist in the West, who did not want to be named. Instead of chucking people out of their homes, Watercare opted to cut down a lot of trees in Titirangi, he said.
The trees are located in a 3.5ha block of land owned by Watercare around the Huia plant at Waima, just outside Titirangi. The land has been designated for water supply purposes since 1972.
The land is also in a Special Ecological Area(SEA), which presents all kinds of challenges for the water company and opens the door for environmental groups and others to challenge the $400 million project.
Speaking inside bush earmarked for the chop, Watercare's environment and consents manager Mark Bourne openly admits the area has some outstanding natural features.
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However, he says Watercare is preserving areas of particularly high value. This has included splitting the project into three sites so no kauri trees are removed, minimising the volume of earthworks and moving one of the two storage tanks to the existing water treatment plant once the old plant is decommissioned.
A high value area containing stands of kauri which intersects with Clarks Bush Track has been protected near the site of the new treatment plant. The site is now mostly regenerating bush from farm land abandoned in the 1930s.
Sarah Flynn, an ecologist from Boffa Miskell working on the project for Watercare, said the building footprint for the new plant has been confined to regenerating kanuka and mahoe forest, scrub and exotic weeds.
She said the SEA classification, which includes the presence of threatened species and high ecological diversity, does not mean the whole site has uniformly high ecological value - "in fact it doesn't".
Bourne acknowledges the project is a balancing act between the needs of providing 20 per cent of Auckland's drinking water and environmental issues.
Last August, he said, Watercare sought public feedback on a resource consent for removing vegetation and earthworks and received 500 submissions. The vast bulk of submissions opposed the project. Just 20 supported it. Hearings take place next month.
A report on the application by Auckland Council officers said it would have more than minor adverse effects on the environment, particularly on ecology, but after looking at the measures to mitigate the effects "it is recommended that consent is approved, subject to conditions".
"Clearly the community has some concerns and wants to have a voice," Bourne said.
Two years ago, Watercare formed a community liaison group to bring community and environmental groups together to find ways of minimising the negative effects.
It was made up of representatives from a number of groups, including Titirangi Protection Group, Waitakere Ranges Protection Society, Titirangi Residents and Ratepayers Association, Tree Council and Forest and Bird's Waitakere branch.
Paul Walbran, chair of Watercare's environmental advisory group and a former Auckland Regional councillor, has chaired the group. Independent expert advice for the group has been funded by Watercare.
Walbran said by and large the process has been engaged in good faith.
"It could have achieved more, but on the other hand the community groups felt they still have a chance to halt the process completely and they didn't want to weaken that opportunity," he said.
Many submitters remain vehemently opposed, but a number of community and environmental groups acknowledge the designation on the land for water quality use means Watercare will probably get consent to remove vegetation and earthworks. They are pushing for tighter conditions and more compensation for a community trust.
Titirangi Residents & Ratepayers Association chair Dr Mels Barton says the group is under no illusion this is essential infrastructure for Auckland and it is "extremely likely" the consent application will be approved.
But she said the plant is on an industrial scale that will hurt the environment and questions if Huia is the "best site or the most convenient one" for Watercare.
The site is likely used by a number of threatened species including bats, geckos, a new species of flightless parasitic wasp, a rare slave ant, a velvet worm, birds and other fauna and flora, the association says in a submission.
There is also a biosecurity risk of spreading kauri dieback and Argentine ants, plus the potential for sediment pollution of downstream watercourses.
Barton appreciated the removal of one of the reservoirs from the side of the road with the best ecology across the 3.5ha site, but does not believe mitigation has gone nearly far enough to avoid the negative effects and impacts.
The association is happy with Watercare's proposal to set up a community trust with $5 million over 10 years for pest and weed control in the Waima catchment as compensation for the ecological losses, but says it should receive $20m over 20 years and $10m for maintenance over the following 80 years.
John Edgar, president of the Waitakere Ranges Protection Society, is another local figure philosophical about the Huia upgrade.
"Watercare have had this property for 100 years and have a designation on it. They can do this. All we can achieve out of this is better consent conditions," he said.
The society remains concerned Watercare is not doing enough to address the adverse effects and, like the residents association, wants funding increased over a longer term for the community trust.
Forest and Bird and the Tree Council oppose the application, partly because of its potential to spread kauri dieback and Argentine ants.
In a submission, Forest and Bird said kauri are present within and adjacent to the footprint of the new plant, a tree under threat from a disease that will result in the collapse of the kauri ecosystem.
The area of native vegetation removal and substantial earthworks and earth moving equipment risk the introduction or spread of the disease, Forest and Bird Auckland regional manager Nicholas Beveridge said in the submission.
The Tree Council submission said Watercare acknowledges the threat posed by kauri dieback and its associated ecosystem, but "grossly underestimated the risk of spread of kauri dieback disease posed by this proposal".
The council criticised Watercare's "flawed approach to only invoke strict hygiene precautions for kauri in excess of 20cm in diameter", saying the size of the tree is not relevant for hosting the spores of the disease.
"All kauri need to be assumed to be infected on the site, regardless of age or size," the submission said.
Beveridge said another risk is the spread of Argentine ants that have been found nearby and could be introduced to the site by vehicles, machinery, soil and plant material.
Simon Kitson, of the Titirangi Protection Group, has raised another issue - Auckland councillors unanimous decision last year to declare a climate emergency, which, he says, Watercare is bound to follow.
"Why haven't they produced an assessment of the climate impacts of this proposal. To grant this consent would make a mockery of national and local objectives towards reducing climate change emissions," Kitson said in a submission.
A big issue for locals is the social impact of the project, which includes up to 118 two-way truck movements through Titirangi village for nearly a year, and several years of construction.
Barton said communities using Titirangi's roads are dreading the impact of the works, local schools will be seriously affected by congestion caused by traffic controls and there is concern at the potential effects of vibration on houses on Atkinson Rd from heavy vehicles negotiating speed bumps.
Ken Turner, who has run a motor business on the same road as the Huia plant for 40 years and a member of the Waitakere Ranges Local Board, says the project is a massive piece of city infrastructure that will have the same impact on locals as the Waterview tunnel project had on that community.
"By the time it is finished it will shag our roads. The people having coffee in Titirangi, it is going to have an impact on them too," he said.
New duties for old buildings
Two buildings with historic links to Waitākere's water supply will get a new lease of life if Watercare gets the green light for its Huia project.
The decaying and vandalised Nihotupu filter station, built in 1927, and the historic wing of the Huia water-treatment plant, built in 1928, will be restored, potentially for office space or as a water-supply museum.
The Waitākere Ranges first began supplying water to the city in 1902 to meet population growth and five large dams were built in the 20th century. Along with these came reservoirs, piping tunnels, filter stations and other structures.
Watercare has offered to restore the Nihotupu filter station at an estimated cost of $3.8 million. This will involve bringing it up to modern earthquake building standards.
A Watercare spokeswoman said once the new Huia treatment plant was built it would look to repurpose the historical part of the existing plant. "We will engage with the community to decide what the buildings are used for," she said.
Engineering Heritage New Zealand, along with former Waitākere Mayor Sir Bob Harvey and long-serving local politician Sandra Coney, are backing the proposal to restore the Nihotupu filter station.
The filter station stands at the entrance to Exhibition Drive. It closed in 1990 and has been subject to vandalism and gradual decay.