To: Wellington Regional Council
The application includes:
Restricted Coastal Activities to construct and maintain seawalls in the CMA and to disturb the CMA in constructing the seawalls;
A Coastal Permit to occupy and use the CMA for rock seawalls totalling 1000m over a 2500m length of the southern shore of Pauatahanui Inlet.
The Guardians oppose certain aspects of the application, while acknowledging that new erosion protection is necessary.
The reasons for our concerns are
- Roading has significantly altered the natural character and ecological values of Pauatahanui Inlet and its margins. The existing roading configuration results in adverse consequences for the Inlet's ecological and recreational values. Proposals to upgrade the existing roads to cope with increased traffic (especially existing State Highway 1, State Highway 58 and Gray's Road) will lead to greater adverse environmental effects, and increased danger in walking or cycling the perimeter of the Inlet.
- The proposed rip-rap facing appears to be based on the recent pilot at Brown’s Bay and the current refacing at Mana Marina. This is composed of bright and “blue” greywacke that is quite different in texture, hue and reflectance to the natural fractured rock surfaces adjoining the inlet. These are mainly red or black siltstone and sandstones, of dull and weathered texture, with a mosaic of low stature indigenous vegetation further softening the hard surfaces.
- The large size of the placed rocks leaves large interstices, especially at the top, effectively preventing any accumulation or retention of fine materials suitable for establishment of hardy indigenous vegetation such as taupata.
- The shallow slope chosen and the thickness of the facing used results in the base of the facing encroaching a further two metres into the coastal marine area. This could result in a consequential reclamation of approximately two square metres per metre of refaced road, or 5000 cubic metres if all of the proposed consent was exercised. This would add to the cumulative loss of tidal compartment contributed to by earlier reclamations, causeways and sedimentation. Loss of tidal compartment, or intertidal volume, may contribute to further declines in the flushing capacity of the inlet.
- The previous phase of sea wall refacing used a variety of more natural stones set into a concrete matrix. This has weathered to a less stark surface than similarly weathered greywacke rip-rip. There would be some benefit in reviewing the costs/benefits and reasons for that previous style of facing.
We request that Council impose conditions on any consents granted to ensure that:
- The roadway is not realigned or extended any further into the inlet than the existing roadline.
- The rock facings extend into the Inlet as little as possible so that the tidal compartment is not reduced.
- The top of the facing/road-edge is surfaced in a way that facilitates use by pedestrians and cyclists.
- The walls are constructed from materials and in a way that minimizes adverse effects on the natural character of the margins of the inlet. This should include a planting trough embedded near the top of the rock facings, where practical and appropriate, to accumulate silt and provide an initial site for the establishment of indigenous vegetation, such as taupata and kowhai.
- An appropriate degree of restoration is undertaken of saltmarsh, seagrass meadows and other indigenous estuarine communities in similar locations to where these have been damaged or destroyed by earlier road construction or maintenance activities.
- No vehicles are used on intertidal flats for construction or maintenance purposes except where this can be undertaken without damage to sediment structure and biota.
The Guardians wish to be heard in support of this submission
Copy to: Transit New Zealand,
C/- Paynes Royd,
PO Box 9624,
WELLINGTON
Attention: Dougall Campbell
Guardians of Pautahanui Inlet
PO Box 57034, Mana, Porirua City
