Under the terms of its resource consent, Watercare is allowed to overflow sewerage into the harbour twice per year per engineered overflow point. At some 50 locations in the western isthmus, such as here in Herne Bay, the overflow is tripped almost every time it rains, spilling around 2.2 million cubic metres of diluted wastewater into the harbour each year.

What happens on land flows to sea. In the urban context, this comprises sewerage overflows and stormwater run-off which contains industrial chemicals, contaminants and heavy metals. We need to clean up our act.