Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Important Porirua Harbour habitats at risk

Important Porirua Harbour habitats at risk


The results of a recent survey show sediment entering the harbour continues to be a problem in Porirua Harbour.

The latest five-yearly survey of Porirua Harbour intertidal habitats has shown that the area of estuary covered in freshly deposited mud has increased substantially, particularly near the Kakaho and Horokiri streams.

Soft mud reduces the water clarity, the amount of oxygen in the sediment, and the growth of vital seagrass. This results in a loss of habitat, reduces recreational and aesthetic values and the estuary’s ability to function effectively.

The density of seaweed growth near the mouths of the Porirua, Pauatahanui and Horokiri streams is evidence that nutrient inputs (nitrogen and phosphorus) remain high. Seaweed mats can smother sediment and seagrass. When the seaweed dies it starves the sediment of oxygen and causes black smelly mud.

Although there are large, healthy areas of saltmarsh in the eastern Pauatahanui Arm, saltmarsh is absent in the Onepoto Arm of the harbour. Saltmarsh areas are highly productive, provide valuable habitat for fish and birds, and offer flood and erosion protection.

“Though this is only the second habitat mapping survey in Porirua Harbour, the findings confirm that important habitats such as seagrass and saltmarsh remain vulnerable to the effects of human activities on land” says Greater Wellington Regional Council’s Coastal Scientist, Dr Megan Oliver.

“Sediment and nutrient inputs from the surrounding land and waterways are reducing sediment quality, biodiversity and healthy functioning of the estuary”.

The Regional Council commissioned the second broad scale habitat mapping survey of the intertidal area to assess the changes in key estuary habitats (eg, saltmarsh and seagrass) and substrate (e.g. areas of mud and sand).

The information has been gathered as part of the Regional Council’s State of the Environment Monitoring requirements under the Resource Management Act.
Information from the report will feed into the Porirua Harbour and Catchment Strategy and Action Plan’s sediment reduction and estuary restoration work and help focus policy and management decisions related to land-based activities.

The Strategy and Action Plan is a council and community project that has been prepared and adopted by four key stakeholders – Te Runanga o Toa Rangatira, Porirua City Council, Wellington City Council and Greater Wellington Regional Council - along with 10 other agencies. A new joint committee of the four organisations is now being set up to work more closely and to oversee the implementation of the strategy.

Ngati Toa Rangatira kaumatuaTaku Parai says it’s good that the regional council is closely scrutinising the condition of the harbour to ensure everyone is aware of these issues and helps to turn them around.

“Loss of significant habitat in the harbour is a problem that has affected Ngāti Toa for many generations. Having access to the information provided by these surveys is empowering for iwi and the whole community to work together for positive change,” says Mr Parai.

The issues arising from the survey are being addressed as part of the harbour strategy.

Porirua Mayor Nick Leggett and Regional Councillor Barbara Donaldson point out that a lot of work is happening including sewer and stormwater upgrades, community education, the development of an estuary restoration and catchment revegetation framework, research and a review of the region’s regulations
Work on a catchment erosion control plan will be completed in February followed by its implementation. This, along with improved earthworks control, will have an impact on reducing sediment entering the harbour. It’s also a reminder to the community that re-vegetation of the catchment is one of the most significant things we all can push to reduce sedimentation.

Over summer, the regional council will be carrying out routine annual measurements of sedimentation in the harbour. There are also plans to undertake habitat mapping of the subtidal areas of the harbour.

The report can be downloaded from the document library on GWRC’s website – search for “Porirua Harbour broad scale survey” or visit http://www.pcc.govt.nz/Publications/Porirua-Harbour-and-Catchment-Management-Programme

ENDS

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

International Rankings: Student Results 'Show More Resourcing Needed'

NZEI: "For the second time in a week, international assessments show we have a problem... We need to put more resources into schools in high poverty communities to ensure all kids get the support they need."

New Zealand had only held relatively steady in international rankings in some areas because the average achievement for several other OECD countries had lowered the OECD average -- not because our student achievement has improved. More>>

 

Salvation Army Report: Beyond The Prison Gate Report

A new Salvation Army report says changes must be made to how prisoners re-enter society for New Zealanders to feel safe and secure in their homes and communities. More>>

ALSO:

Surprise Exit: Gordon Campbell On The Key Resignation

The resignation of John Key is one thing. The way that Key and his deputy Bill English have screwed the scrum on the leadership succession vote (due on December 12) is something else again. It remains to be seen whether the party caucus – ie, the ambitious likes of Steven Joyce, Judith Collins, Paula Bennett, and Amy Adams – will simply roll over... More>>

ALSO:

Q+A: Labour's Michael Wood Wins Mt Roskill

Labour’s Michael Wood, who last night won a 6,000 vote majority in the Mt Roskill by-election, says the reason for the win was simple, clear messaging... More>>

ALSO:

Gordon Campbell: On Anne Tolley’s Callous Folly

Last week’s conflict between Social Development Minister Anne Tolley and District Court judge Carolyn Henwood illustrated quite a few of the flaws in the system. More>>

ALSO:

Members’ Bills: Greens' Domestic Violence And Loans Bills Pulled From Ballot

Jan Logie’s Domestic Violence-Victims' Protection Bill introduces workplace protections for victims of domestic violence, including allowing victims to request paid domestic violence leave for up to 10 days... Gareth Hughes’ Bill allows Kiwis with student loans to defer their student loan repayments into a first home savings scheme. More>>

ALSO:

IPCA: Police Did Not 'Deliberately' Use Pepper Spray On 10-Year-Old

"When spraying the man, the officer did not properly consider the necessity of using pepper spray in a confined space, the likelihood that it would affect the other innocent passengers or the fact that he was using a more powerful spray." More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news