'Don't dump it here'
Plans to release much of Auckland's wastewater into the Manukau Harbour have met a storm of opposition from waterfront residents.
Watercare has received 468 submissions from Mangere Bridge people and groups ahead of public hearings on its "central interceptor" project.
The feedback makes up the bulk of the 752 submissions on the project's resource consent applications.
The interceptor, a 13km underground tunnel, will take up to two million cubic metres of sewage and stormwater to the Mangere treatment plant every year.
It will also include 6km of linking sewers and create a long-term replacement for an ageing 7km tunnel section - the Manukau Siphon - near the plant.
The $800 million proposal aims to improve the water quality of the Waitemata Harbour and reduce or eliminate 122 flooding spots, mostly in Avondale, Western Springs and Mt Albert.
But Mangere Bridge residents say those improvements will come at a cost to the environment.
Many of their submissions were completed on forms distributed throughout the community by the Mangere Bridge Residents and Ratepayers Association.
The form says the proposal could have dire effects for the water quality of the harbour and birds roosting in the area.
"It is not good ecological practice to transfer large amounts of water from its natural catchments to a shallow enclosed harbour with finite capacity to receive it," the form says.
Te Akitai Waiohua Waka Taua Trust, which is associated with Pukaki Marae, has also lodged numerous submissions against the proposal.
The trust says there has been insufficient consultation with tangata whenua regarding stormwater discharge, air discharge, earthworks and coastal structures.
But Watercare chief executive Mark Ford says his organisation has a "strong record" of community consultation on major projects such as this one.
The central interceptor proposal reflects international best practice and will save Auckland more than $500m going forward, Mr Ford says.
Major upgrades are also being planned for the Mangere treatment plant to address Auckland's wastewater needs.
"These will ensure continued protection of the Manukau Harbour and enable the Mangere wastewater treatment plant to continue to operate within its current discharge loads into the future."
Watercare also intends to divert the wastewater flows of about 75,000 existing households from Mangere to a plant in Rosedale by constructing another tunnel from west Auckland to the North Shore.
Public hearings on the central interceptor proposal will be held from July 29 to August 9 at the Manukau Civic Building at 31-33 Manukau Station Rd starting from 9.30am every day.