5 April 2016

Work is now underway on four more sites along the Sumner Lyttelton Corridor - Wakefield, Moa Bone and Clifton Hill, and work will start at Deans Head once necessary consents have been obtained. 

Wakefield
Work has begun at the Wakefield site, scaling back rock before the bund is constructed.  This work is estimated to take six months, weather permitting.  HEB Construction are doing these works. For any queries or concerns please contact Delroy Riley from HEB, on 027 273 7976, or delroy.riley@heb.co.nz  

Working closely with the Department of Conservation, herpetologist (lizard expert) Marieke Lettink has relocated skinks found at the Wakefield site to Cavendish on the Port Hills above Sumner Road, where a restoration programme has seen planting to provide a habitat and food source for the skinks.  Marieke is working closely with the Department of Conservation on wildlife permits and conservation offsets as part of the Sumner-Lyttelton Corridor works programme.

Southern grass skink (left) and a funnel trap containing several skinks (right)

Moa Bone
At Moa Bone, works to enable benching of the slope and rock contouring have begun.  The works are expected to take six months, weather permitting.  Fulton Hogan are doing these works, with Brian Fitzgerald the construction contact for any queries or concerns, phone 027 228 6478, email brian.fitzgerald@fultonhogan.com 

Pedestrian crossing work
Work will start soon to upgrade the footpath connection on the estuary side near Moa Bone Cave. This will involve sealing the footpath connection, which links the road edge to the footpath, at the island near the Beachville/McCormacks Bay intersection.

Clifton Hill
Initial works here will see the rockface scaled, and stormwater controls built at the top of the cliff.  The rockface will then be covered with mesh and bolted to reduce rockfall risk, and the fallen rock will be contoured.  These works are estimated to take six months, weather permitting.  Fulton Hogan will be doing this work.  Please contact Brian Fitzgerald with any queries or concerns, phone 027 228 6478, email brian.fitzgerald@fultonhogan.com

Deans Head (and Shag Rock Reserve)
The works here, being managed by LINZ, involve removing the unstable soil and contouring the site, to reduce the mass movement risk.  Part of this work will be completed from within Shag Rock Reserve.  The first stage of the works involves removing debris and contouring hillside to enable access from Shag Rock Reserve up onto the Deans Head slope.  The earthworks will take six to nine months (weather dependent) and are expected to be finished in late 2016. Re-vegetation and other property maintenance will start on completion of the earthworks. Please contact LINZ with any queries on 0800 665 463 or customersupport@linz.govt.nz

Three memorial lamps, located behind the shipping containers, are of heritage significance and will be salvaged by the contractor before any works start. The lamps were originally built in 1939 and restored in 1980 by the Sumner Redcliffs Historical Society. Electricity was connected and the lamps lit for the first time in 2004. The Council will work closely with the Sumner and Redcliffs communities to find a new future location for the lamps.

During consultation in November last year about fencing along the Corridor route, we became aware of concerns from some groups in the community around the aesthetic component of the fencing.  In response to these concerns, we will now complete a second consultation with the community about this aspect of the works.

The project team are currently planning for this consultation, aiming to go out to the community next month.  We will provide further information on this in the next newsletter, and let you know how you can be involved.

Landscape architects are working on the details of planting plans for sites along the Sumner Lyttelton Corridor:

Planting at Wakefield bunds

Bund 1, 72-96 Wakefield Avenue (Wakefield Avenue between Campbell & Paisley Streets)

The bund has been set back about two metres in some parts, and wherever possible there will be planting in front of the bund to visually soften the structure.  The planting will be local natives and eco-sourced, the species chosen to be in keeping with the native vegetation lost when the bund was constructed.  Detailed planting plans will include shrub and tree species that tolerate coastal environments, such as ngaio, akeake, cabbage tree and hebe. Where possible and feasible, planting is proposed to the top of bund. Coastal tolerant sprawling species, such as New Zealand ice plant and scrambling pohuehue, will be used.

 

Bund 2 - 34 Wakefield Avenue - 26 Nayland Street

This bund has been setback about two metres to allow for landscape planting. The face of the bund will have a 'rock basket look', providing a connection to the rock cliffs behind. The landscape planting will aim to 'bed' the bund structure into the streetscape while also providing a separation of the structure for pedestrians. The plant species will be hardy to the coastal and street environment and in keeping with any proposed planting in the streetscape to further integrate the structure.

Bund 3 - 70 Wakefield Avenue (opposite the intersection of Wakefield Avenue & Denman Street)

Given the site constraints of the bund a setback here is not possible, therefore no landscape planting is proposed in front of this bund.  However, where possible and feasible, planting is proposed on top of the bund to visually soften the structure.  Coastal tolerant sprawling species, such as New Zealand ice plant and scrambling pohuehue, will be used.

Shag Rock

Given the site constraints a setback of the bund here is also not possible.  Landscaping of the site will involve concentrated planting at each end of the bund structure to create a lizard habitat where lizards are most likely to colonise naturally.  Where possible and feasible, selected pockets' of planting is proposed to visually soften the structure.  Detailed planting plans are underway which will include plant species that are local natives, eco-sourced, coastal tolerant and that provide a beneficial habitat and food source for lizards.  This may include silver tussock, scrambling pohuehue and prostrate kowhai.

Following questions from the Hagley/Ferrymead Community Board, the Council's Senior Geotechnical Engineer recently put together some information about geotechnical hazards along the Sumner Lyttelton Corridor route.  We thought this information may be of interest to all of our e-newsletter subscribers.

Geotechnical risks Moa, Clifton, Wakefield - Dr Ian Wright, Senior Geotechnical Engineer

Introduction
Slope instability associated with the bluffs and steep cliff faces along Clifton, Moa Point and Wakefield presents a life risk.  The earthquakes caused a large amount of debris to shed from these faces, in the form of large avalanches, often referred to as 'cliff collapse' and isolated boulders either detaching from the bluffs and cliff faces or further up the slope.  Sadly, there were five fatalities caused by these hazards in the February 22 earthquake, three from people being caught within the cliff collapse area and two from rockfall.

Science
GNS Science has done a great deal of work looking at slope instability hazards and have identified specific areas within the Wakefield Ave - Main Road area that are subject to these hazards. They have also undertaken a risk analysis for residential properties located within these areas of known hazard. Their work has included compiling a series of maps which identify the annual individual fatality risk for a 'typical' resident living in the Port Hills, as well as limited risk analysis to road users in the shadow of some of these hazards. These reports are available on the Council website.

The Council has used the GNS work as a basis for designating slope stability management areas which have specific planning rules associated with them.  These rules are now considered operative as part of the District Plan. Properties that fall within these areas can be searched on the Council website.

Many of these areas affected by slope stability hazards were 'red-zoned' and may, also have been included in a CERA S45 zone (a hazard zone). Where the Crown owns the property or where a property falls within an S45 area, CERA has very strict access controls to prevent unauthorised access due to the danger posed by these hazards.