Harbour health a concern
Rubbish on the decline, but still a blight
The large amount of rubbish entering Porirua Harbour remains a concern, but the overall health is on the rise, according to a newly released ‘‘scorecard’’.
Wellington Regional Council recently completed a mapping and inter-tidal survey of the harbour as part of an action plan to improve its overall health.
The plan is part of a project adopted by Porirua and Wellington City councils, the regional council and Ngati Toa, with help from 10 other agencies.
One of them is the Porirua Harbour and Catchment Trust. Its chairman, Grant Baker, said its own state- of- the- harbour scorecard revealed several positives.
The trust’s review panel looked at agency action, sedimentation, recreational usage, ecological health and waste.
‘‘There is a perception from the regular harbour users that it is improving, giving it an overall 4/5 mark,’’ Mr Baker said. ‘‘They say the water quality has improved and they rate their on- water experience as good.
‘‘The feeling is that things are starting to happen, which is great.’’
What was not good was the rubbish, such as tyres, road cones and shopping trolleys, that are still coming from the Porirua Stream.
‘‘It’s an ongoing issue. In 2009, there were over 400 items taken out of the Onepoto Arm and in the last two years the trust and Keep Porirua Beautiful have done a clean-up there in November.
‘‘In November we took out 172 large items, 132 of which were tyres. It’s down from 260 items in 2012, but it’s still too much.’’
The Porirua Harbour and Catchment Trust gave the agency action — help from organisations that said they would provide funding towards the harbour’s health — a 3/5 mark.
Sedimentation it rated 5/5 in the Pauatahanui Inlet and 3/5 in Onepoto. Mr Baker said an increase of soft mud in the harbour, from three hectares to 20 hectares in five years, was a concern.
Further work on reducing the inflows and achieving the action plan target of 1mm per year was needed, Mr Baker said.
The scorecard’s water quality marks varied.
The trust ranked the quality at Paremata Bridge 4/5, Plimmerton Beach, Karehana Bay and the water ski club on the Inlet 3/5, and 2/5 at the rowing club at Onepoto.
The Porirua Stream’s health at Wall Place received a rating of 3/5, but 4/ 5 at Horokiri and Pauatahanui streams.
Mr Baker said the regional council’s testing regime, and making the results readily available, was appreciated.
‘‘The data is very important and it allows us to cherry pick a lot.
‘‘ What we’re doing with the scorecard is setting a benchmark that we’ll use every year from now on. With the work starting on Transmission Gully, we can track what effect that will have, too.’’
Mr Baker said the trust would do a scorecard every February.
Ngati Toa kaumatua Taku Parai said close scrutiny of the harbour by the regional council could only be good.
‘‘Loss of significant habitat in the harbour is a problem that has affected Ngati 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,’’ he said.
Porirua mayor Nick Leggett said stormwater and sewer upgrades, community education and the development of an estuary restoration and catchment vegetation framework were among the projects Porirua City Council was committed to.
There was a tighter earthworks policy and an erosion control plan coming, Mr Leggett said.
For the Porirua Harbour and Catchment Trust’s full scorecard, go to poriruaharbourtrust.org.nz.
Looking down: Porirua Harbour’s health has been the subject of extensive policy work, discussions and strategy meetings in the past few years.