An unassuming structure in a Whangarei park will be the last major plug in a plan to keep Whangarei Harbour free of sewage.
The 600cum wastewater tank at Tarewa Park follows two similar projects in the city, working towards the goal of having no shellfish bed closures from sewage leaks during major storms.
An existing pipe near the park reserve discharges raw sewage into Waiarohia Stream - which runs into the harbour - during major weather events, usually about three or four times a year.
Whangarei District Council waste and drainage manager Andrew Carvell said the $4.5 million tank - due to be built in 2016 and 2017 - would stop these overflows.
The project budget included increasing the capacity of the sewer line along State Highway 1. By 2017, the council will have spent $30 million over 10 years upgrading its drainage network.