NEW ZEALAND: Broader water quality guidelines outlined

Barry Hart, an academic at Monash University in Victoria, Australia outlined new water quality guidelines for New Zealand and Australia at the Water 2000 Conference in Auckland.

The new guidelines cover six ecosystem types, compared to the present two. They also identify issues or problems caused by stress factors which affect the environment such as physical and chemical pollutants. Instead of water quality being judged by individual indicators, the new guidelines provide for an integrated assessment using a risk-based approach with emphasis on local conditions. Specific information will be sought on each site before decisions on water quality are made, Hart said.

The new guidelines will apply to both Australia and New Zealand. Hart said they will provide a framework for better management and protection of ecosystems over the next few years. To remain effective, they need to be updated and further developed, he said.

Likely areas for review include the refinement and updating of triggers to measure physical, chemical and sediment indicators in water. The review will look at what investigation should be done where these triggers are exceeded. Hart said better integration of assessment methods and development of further guidelines for environmental factors affecting water habitats must also be included in any future review and update.

Existing guidelines were issued in 1992, but Hart said they were now deficient in key areas. The present guidelines classify eco-systems into only two categories, ‘fresh’ and ‘marine.’ Hart said this was too broad to offer adequate protection to plant and animal life found in fresh water, estuaries, and coastal and marine systems in different climate zones.

The existing guidelines also assume that if water quality is adequate, so is the whole ecosystem. But, Hart said, this overlooks actions that can cause significant changes to water quality, such as polluted sediments, reduction of stream flows or wetland drainage.