Motions catchment improvements project

Project overview

The proposal

This project forms part of our broader Western Isthmus Water Quality Improvement Programme (WIWQIP) of works which is a joint initiative between us and Auckland Council. It's aimed at reducing wastewater overflows and improving stream and beach water quality across the city’s central western isthmus.

This project aims to transport dry weather flows from several areas to provide capacity to assist with the significant level of growth predicted in the catchment. It will improve the collection and conveyance of wastewater to minimise the occurrence of spills and uncontrolled overflows that occur between the Central Motorway Junction through to Western Springs Park. The proposed pipeline will connect at various locations to the existing network and discharge to the Central Interceptor project at the downstream end.

Once the project is complete, the Engineered Overflow Points (EOP) will meet the current network discharge consent expectation of fewer than two overflows a year at each spilling location.

Geotechnical investigations

As part of the project our contractor will be commencing geotechnical investigations in the community. These geotechnical investigations are required to add to our knowledge of soil, geology, and groundwater conditions for this project. We will begin these geotechnical investigations from mid-May and it is estimated it will take several months to complete. Investigations will take place in reserves and at locations along the proposed tunnel alignment.

In some cases, traffic management will be in place. Please keep an eye out in the coming weeks for further updates on geotechnical investigations.

Timeline for the proposed works

Construction is estimated to take place between 2028-2031. We will provide more specific dates closer to the time of construction. Please note, these dates are estimates and subject to change.