The tank is one of the last projects in a 10-year-plan to prevent storm spills from the district's sewerage scheme into the harbour.
In the past, sewerage pipes would sometimes overflow when rainwater flowed into them during heavy rain. This would then flow into the harbour and result in fishing bans.
In 2008 the people loudly spoke out to stop polluting Whangarei Harbour with sewage.
Whangarei District Council listened, and conceived a 10 year, $26m wastewater strategy. It set out a plan to deal with the major overflow points to prevent these spills.
The strategy came after the 2008 Save Our Harbour protest march through the city, which started after the Northern Advocate questioned why the council had consent to discharge up to 24,000 cu m of raw sewage into the harbour.
As part of the strategy the council has completed a $4 million holding tank and treatment plant on the Hatea River, new sewerage mains and expansion of the Kioreroa Waste Water Treatment Plant and major expansion of the Okara pumping station.
The work at Tarewa Park started in October and will be completed and fully operational in July next year.
The pile of dirt from the hole for the tank will be spread out over the area, which will be returned to green fields once the work has finished.
