In 2010-2011, the council undertook water quality testing at 16 sites in both the Bay of Islands (figure 1) and Whāngārei Harbour (figure 3) and at nine sites in the Kaipara Harbour (figure 5). Sampling was conducted bi-monthly in Whāngārei and the Bay of Islands and monthly in the Kaipara Harbour. One rain-driven sampling event was also done in Whāngārei Harbour and two in the Bay of Islands.
Monitoring sites have been selected to capture the main freshwater inputs into these systems, and to assess water quality across each harbour. Water samples are analysed for physical properties such as temperature, salinity, dissolved oxygen and turbidity – how clear the water looks – and for chemical parameters such as nutrients (phosphorus and nitrogen). The amount of micro bacteria (Enterococci) present in the water is also measured.