For the first time, all the State of the Environment monitoring programmes in the Manukau Harbour and its catchment have been brought together in one Auckland Council report.

The report concludes that ‘without doubt’ past human activities such as direct pollution have had a harmful effect on our local marine environment.

Māngere Inlet has elevated levels of some heavy metals such as copper and zinc in its sediment, while nearby coastal waters show high levels of nutrients and low water clarity.

Encouraging signs

But there is good news. Long-term analysis of water and sediment contaminants show improving trends – thanks to improvements in the quality of the water discharged from the treatment plant, and better site and stormwater management associated with modernising industry around the inlet.

Our harbour is one of the largest in New Zealand. It covers 365km2 and has over 450km of shoreline. It is a site of national importance ecologically, with diverse habitats supporting a huge variety of species. Upwards of 30,000 shore birds use the mud and sand flats daily to feed and coastal spaces to roost.

Time for change

While the Harbour is degraded in some areas, it is also resilient, and responsive to improvements in how the land around it and the water that feeds into it are treated and managed. The report recognises that land-use change and urban development in an ever-growing city pose challenges, but also provide opportunities for better management of our activities on the land and in the sea.

You can view/download the full report here.