Porirua Harbour Trust

Harbour Future Still Uncertain

28 Mar 2017

The Porirua Harbour Trust has completed the fourth comprehensive “State of the Harbour” scorecard which reports on progress toward arresting the decline in harbour condition and returning it to a healthy and resilient state.


In releasing the fourth annual scorecard the Chairperson of the Porirua Harbour Trust, Grant Baker stated that the key concerns are the ecological health of the harbour and streams, particularly the Porirua Stream, the increased level of mud in the Pauatahanui Arm, and water quality of our swimming beaches.


The future health of the harbour is driven to a very large extent by the health of our streams and recent monitoring indicates that stream health is not improving and streams in the Porirua catchment continue to languish in the bottom third for of all streams in the region.


Mr Baker said that the scorecard maps and assesses five indicators related to the harbour and catchment.  The scores are designed to highlight changes in key aspects of harbour and catchment quality and to give an indication each year of progress against the Porirua Harbour and Catchment Strategy and Action Plan.  


The five indicators reported on in the “State of the Harbour” scorecard are: Agency Action; Sedimentation; Education and Recreational Usage; Ecological Health and Waste


Mr Baker said it was pleasing to see a rating of Excellent for the rate of Sedimentation of the Onepoto Arm (subtidal), Pauatahanui Inlet (intertidal and subtidal) and the harbour overall.  The ongoing work as Transmission Gully is built and the significant land development planned across the catchment will be the big test in the next few years.


It is clear that the joint councils are working hard to implement the harbour strategy and they have operational plans in place to arrest the state of decline in the catchment. The Whaitu process will end up modelling the entire catchment and harbour, and setting limits for water quality and quantity in the streams and harbour. While the councils should be applauded for their effort to date and considerable ongoing commitment of resources, we are still some way off seeing the tangible improvements required to achieve the long term goal of returning the catchment to a healthy and resilient state.

The Annual Scorecard produced by the Porirua Harbour Trust is extremely important said Mr Baker. Over the last 20 years the harbour has become increasingly recognised for the wide range of values it has. The harbour is beautiful and more and more people want to live on its edges, or have views across the water to the surrounding hills. Many drive, cycle, and walk around the harbour while others enjoy recreational activities on the water as well as in the surrounding hills. The historic development and use of land around the harbour has however resulted in the steady degradation of values that make the harbour special.


Overall, when considering the longer term data available to the review team, the results show generally positive and progressive actions and improvement in harbour quality and condition over the last decade – with three notable exceptions:

  • the recent readings across the three key streams in the catchment, both for water quality and ecological health show no improvement in stream quality and this is of concern longer term as the quality of the harbour is heavily dependent on the water flowing into it from the catchment.
  • significantly increasing amounts of soft fine mud being deposited in parts of the harbour and particularly Pauatahanui Inlet subtidal areas.   
  • generally poor water quality for swimming at the beaches and shellfish gathering areas with three of our top beaches being given a Poor rating which means that water quality is not always suitable for swimming.


The Trust uses a review panel to consider data available from the Councils as well as the Trust’s own surveys and projects comprising Grant Baker, Chairperson of the Porirua Harbour Trust; Lindsay Gow, Trustee of the Porirua Harbour Trust; Dr John McKoy, Marine Scientist and Clive Anstey, Landscape and Resource Planner.


Overall the fourth “State of the Harbour” report is encouraging in respect of the plans that are in place but it may be some years before we can really say that the tide has turned for the better in restoring the harbour to a healthy state.

The full report is available in the Report Section – 2016 Annual Scorecard.

Email Form close