From the Executive summary:

Auckland Council’s coastal and estuarine water quality monitoring programme began in 1989 and now includes monthly sampling of 35 monitoring sites (31 council and four Watercare Services sites) located in Kaipara, Manukau, Waitematā and Mahurangi Harbours, Tāmaki Estuary, Wairoa Bay, and along the East Coast from Goat Island to Browns Bay. Water samples are analysed for fundamental water quality parameters, and indicators of water clarity and nutrient status. This report summarises data obtained over the five-year period from July 2017 to June 2022; provides an overall water quality ranking for each site using a water quality index developed for the Auckland region; and provides plots of data obtained over the most recent 12-month period (the July 2021 to June 2022 hydrological year – appended).

Several changes have been made to the way data has been analysed and presented in this annual report:

• Data summaries and the water quality index results are presented over periods of five hydrological years (July 2017 to June 2022) to provide consistency with freshwater reporting. Note that previous marine and estuary water quality reports have presented results over three-year periods, and as such, those earlier results are not directly comparable.
• Additional analyses and plots are provided to aid with data interpretation by showing: important relationships among water quality parameters; the influence of seasonality; and general spatial patterns by clustering sites that had similar results for fundamental water quality parameters, nutrients, and water clarity. ...

Auckland Council technical report, TR2023/19

See also

Data files

Coastal water quality annual report 2022 supplementary data file 1 5-year summary statistics

Coastal water quality annual report 2022 supplementary data file 2 annual statistics

Coastal water quality annual report 2022 supplementary data file 3 seasonal box plots