Upper harbour under pressure

A study into the overall condition of the Upper Waitemata Harbour has found that while much of the harbour is generally in good condition, some creeks are under increasing pressure from development.

Over the past two years a comprehensive investigation into predicted future contaminant levels, resulting from land use changes in the Upper Waitemata Harbour has been undertaken. The investigation is part of a study jointly funded by the Auckland Regional Council, North Shore City, Waitakere City and Rodney District councils and Transit New Zealand.

The contaminant investigation shows that concentrations of copper and zinc in some estuaries within the Upper Waitemata are beginning to reach levels that could impact on aquatic life-forms.

The study explores a number of different scenarios that show how contaminant level predictions differ depending on land use and development, the level and type of sediment controls and the extent to which stormwater is treated.

Chair of the Auckland Regional Council’s Environmental Management committee, Cr Dianne Glenn says that the study highlights the threat that contaminants could have on the UWH. “The Upper Waitemata Harbour is surrounded by areas where development is well underway. If we want the main harbour and surrounding estuaries to continue to be in good condition then we need to seriously look at what we can do now, not in 10 years time when it may be too late.”

ARC Project Manager Bridget Thompson says that a range of approaches will help to minimise effects on the diversity of the Upper Waitemata.

“For instance improving stormwater treatment in some parts of the harbour will be more effective in slowing rates of contaminant build-up than in others, where source control and changes to land use and development are more likely to achieve this end.”

A Policy Working Group, with representatives from the four councils involved, has been formed to use the findings of the studies to identify the implications of development in the area, and the decisions that will need to be made to ensure protection of the upper harbour.

This group is expected to report its findings early in 2005.

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