In 2010, the regional council monitored four sites in Whāngārei Harbour, three sites in Kerikeri Inlet and two sites in Ruakaka Estuary, Kaipara and Whangaroa Harbours. The council's estuary monitoring programme uses methods described in the Estuary Monitoring Protocol, which was developed by Cawthron Institute for use by regional councils.
A key element of the programme involves sampling the biological communities of representative intertidal habitats together with the physical (sediment particle size) and chemical properties (nutrient and metal contaminants) of the sediment. This helps us understand the environmental factors that are influencing the biological communities at different sites.
Concentrations of metal contaminants are assessed against the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC guidelines).