These guidelines provide water managers with tools and guidance to assess, manage and monitor water quality. These guidelines were previously know as ANZECC. They complement the existing National Policy Statement for Freshwater Management (Freshwater NPS) which is the main direction to local government about how to manage freshwater in New Zealand.
Link to the guidelines
Australian and New Zealand Guidelines for Fresh and Marine Water Quality [Australian Government website]
About the guidelines
The guidelines are a useful tool to help in managing freshwater and marine water quality.
They are not mandatory but in New Zealand they are sometimes used to assist in managing water quality and aquatic ecosystems. They are useful for pinpointing areas where further investigation may be required, or to inform decision-making related to freshwater management.
The guidelines include Default Guideline Values (DGVs) which if exceeded indicate that further analysis may be needed to make sure aquatic ecosystems are adequately protected. DGVs can provide a generic starting point for assessing water quality.
Each new or revised DGV will be published as a draft for public comment for a period of three months. See Draft default guideline values [Australian and New Zealand Guidelines for Fresh and Marine Water Quality website]
If you want to know when the revised guidance has been published, please subscribe for updates on the Australian and New Zealand Guidelines for Fresh and Marine Water Quality website.
- For toxicants (things which can be directly toxic to aquatic species, like copper or zinc) the DGVs are based on the levels at which these toxicants have adverse effects on aquatic species. The DGVs for toxicants are the same across Australia and New Zealand.
- For physical and chemical stressors (things like nutrients) that can impact on the health of aquatic environments, the DGVs are based on looking at reference sites (sites that have not been significantly impacted by people) to provide an indication of where a site might be less healthy than its natural state. The DGVs for physical and chemical stressors are specific to different types of New Zealand rivers based on the River environment classification.
- The guidelines also provide methods for determining more specific guideline values where desired, for example where a council may want more specific information than provided by the DGVs.
How the guidelines relate to the Freshwater NPS in New Zealand
The guidelines complement the existing National Policy Statement for Freshwater Management (Freshwater NPS) which is the main direction to local government about how to manage freshwater in New Zealand.
The Freshwater NPS is designed to help communities make decisions on how to manage water quality, including setting minimum acceptable states called “national bottom lines” which councils must meet, or work towards meeting over time.
The DGVs in the guidelines, on the other hand, indicate a level to trigger further analysis and monitoring to determine whether aquatic ecosystems are adequately protected. They are a prompt to investigate in more detail, rather than a standard that has to be met.
Although they’re not mandatory, regional councils sometimes use the guidelines to inform water quality objectives and limits in their regional plans where there are no appropriate attributes set out nationally in the Freshwater NPS.
The 2018 update to the guidelines
The guidelines were updated in 2018, and they replace a previous set of guidelines commonly referred to as the ANZECC 2000 guidelines. See History of the water quality guidelines [Australian Government website].
The revised 2018 guidelines were the result of several years of work by the Australian and New Zealand governments to ensure the guidelines were specific and reflected up-to-date scientific information.
Key changes in the 2018 guidelines for New Zealand
- For New Zealand, new or updated DGVs have been provided for sediment (water clarity, suspended solids, and turbidity), electrical conductivity, pH, dissolved oxygen, water temperature, nutrients (nitrogen and phosphorus), copper, zinc and a broad range of other toxicants. A DGV is also provided for sedimentation in estuaries.
- Physical and chemical stressor DGVs for aquatic ecosystems are now classified by climate and source of river flow classes from the River environment classification. Using the River Environment Classification allows for a better accounting of natural variation in environmental conditions across New Zealand.