Porirua Harbour and Catchment Management Programme

This page describes the Porirua Harbour and Catchment Management Programme, with reports, links and video showing a Day in the Life of Porirua Harbour which includes Pauatahanui Inlet and Onepoto Arm.

A Day in the Life of Porirua Harbour

View a short video showing a Day in the Life of Porirua Harbour (3.37mins via YouTube) produced by Keith Calder, Porirua Harbour Strategy Coordinator at Porirua City Council.

 
On this page:
 
 

Porirua Harbour is the Centrepiece of the City

Porirua Harbour, comprising the Onepoto Arm and the Pauatahanui Inlet, is considered by Council and community as the centrepiece of the City. The Harbour is the largest estuary system in the lower North Island. As well as having a nationally significant wildlife area, the estuary has cultural, recreational, economic (transport), and other wildlife habitat values.
 
Porirua City Council has appointed a Porirua Harbour Strategy Coordinator and is the lead agent in the Porirua Harbour programme and committed to developing and implementing a Harbour and Catchment Strategy aimed at Harbour protection and restoration.
 
Porirua City has initiated a strategy development programme with partners Te Runanga O Te Rangitira, Greater Wellington Regional Council and Wellington City Council (70% of Porirua Stream catchment is in the Wellington City district), involving four phases and the following timetable:
  • Partnership – forming partnerships with key agencies and organisations – 2008-10
  • Research – a targeted research and monitoring programme - 2008-10
  • Planning – public Strategy development and preparation process – 2008-11
  • Implementation – 2010 onward
The Council will continue an existing work programme for restoration planting and a landowner advisory service aimed at reducing catchment erosion and improving stream water quality.
 
The Council is also developing or reviewing a number of policy and programmes that will benefit harbour protection and public enjoyment that includes:
  • Review of strategic infrastructure assets (stormwater, sewerage, water reticulation and landfill)
  • City Centre Revitalisation
  • Porirua Development Framework
  • Harbour walkway development

Harbour and Catchment Research

Porirua City Council and Te Runanga O Toa Rangatira with support from Greater Wellington Regional Council, Wellington City Council, and the Pauatahanui Inlet Community Trust are committed to ongoing critical research that identifies and monitors the biophysical condition of the Harbour and catchment. A series of annual and longer term research projects are underway to monitor changes with the harbour.

Projects completed in 2009 were:

  • 'Fine Scale Monitoring' assessed the ecological health of selected locations in the Harbour by analysing sediment nutrients, toxins and biota;
  • 'Broad-scale Habitat Mapping' assessed the sediments and habitat within intertidal areas of the Harbour;
  • 'Ecological Restoration Priorities for the Porirua Stream and its Catchment' identifies the native species and habitat in this extensive stream system, the threats to these and other natural resources, and recommendations for ecological restoration.
  • 'Porirua Stream: your stream, your catchment' provides a easy-to-read summary brochure of the main 'Ecological Restoration Priorities' report above. It also provides a lift-out 'Best Bets' planting guide of restoration plants.
  • 'Porirua Harbour Bathymetric Survey' describes the processes and results of the most comprehensive and accurate survey of the Harbour's seabed.
  • 'Patterns and Rates of Sedimentation Within Porirua Harbour' (Available mid November 2009) compares the 2009 bathymetric survey with previous surveys dating back to 1849. Particular analysis of sedimentation changes between the 1974 survey and today.
  • 'Porirua Harbour Targeted Intertidal Sediment Quality Assessment' provides more detailed assessment of some specific areas of contamination.
  • 'Porirua Harbour Intertidal Macroalgal Monitoring' analysis of the coverage and significance of algae growth (predominantly sea lettuce - Ulva) within the Harbour.
  • 'Stormwater Contaminants in Urban Stream in the Wellington Region' includes and has significant reference to the Porirua Stream.
  • Porirua Harbour Subtidal Sediment Quality Monitoring records the results of the November 2008 survey.

These reports highlight a number of critical aspects about the biophysical condition of the Harbour and catchment:

  • moderate levels of heavy metal contamination in areas of the Onepoto Arm and concerning levels of DDT in both arms of the Harbour.
  • confirmation of significant sediment accumulation, particularly in Pauatahanui Inlet
  • algal growth is a good indicator of nutrient enrichment problems for the Harbour
  • significant opportunities to improve stream quality
  • despite these challenges, the Harbour still has the basis of a sound ecology that would benefit from reductions in sediment, contaminants and nutrients entering the Harbour.

The reports are available to view from the links below.

The focus of current research for 2010 is the funding and development of a hydrodynamic model for Porirua Harbour and catchment. The three staKeholding councils (Porirua City, Wellington City and Greater Wellington) have partnered with New Zealand Transport Agency and Transmission Gully Motorway Project to undertake the modelling and each use the model for their respective analysis. Field work for the model began before Christmas and it is hoped to have final results from the model before the end of this year. These will then help direct elements of the final strtaegy document and action plan.

Porirua Harbour Bathymetric Chart 2009

Porirua Harbour Bathymetric Chart 2009.

This chart shows the half metre contours within the Porirua Harbour derived from the bathymetric survey undertaken in March/April 2009. The scale on the bottom right of the chart indicates the depth of each contour.

 Future Focus

Programme focus over the first half of 2010 will be to complete preparation of and release a public Discussion Document in late March for the harbour and catchment strategy. The document will seek broad public input on values, issues and expectations related to the harbour and catchment. Responses from the public, businesses, organisation and agencies will be used to shape the eventual strategy document. The document will be publicly advertised and obtainable in hard copy or downloadable from this webpage.

 

Contact Details

For enquiries or more information about the Harbour programme, please contact:
 
Keith Calder
Porirua Harbour Strategy Coordinator
Strategy and Planning
Porirua City Council
PO Box 50-218
Porirua City 5240
Phone: (04) 237 3598
Fax: (04) 237 1445
Email: kcalder@pcc.govt.nz
 

Links to more information

Porirua City Council Links

Public Seminar Series Presentations

Please note: some of these files are quite large, and have full colour maps and diagrams.

Sedimentation:

Contaminants:

Nutrient Enrichment:

Ecology:

General:

External websites

Physical conditions