Transmission Gully is so named because it generally follows the route of the Bunnythorpe to Haywards 110kV-transmission lines.
The desire for an inland alternative route for State Highway 1 (SH1) to bypass the coastal areas north of Wellington has been sought for more than 50 years and its main aim is to provide an essential alternative route out of Wellington.
The Transmission Gully route forms the Linden to MacKays section of the Wellington Northern Corridor road of national significance.
The project team has completed Phase 2 of the project which was to gather information required for the lodging of Notices of Requirement (NoR) and resource consent applications with the Environmental Protection Authority (EPA) on 15 August 2011. The Phase 2 work has been complex and involved 16 different workstreams.
Workstreams
The workstreams are described below:
Geographic Information Systems
A computerised mapping system had been developed to provide visual representations of the project to assist consultants and planners when presenting the project to key stakeholders and the wider public.
Road design
Civil engineering work supported the road design by taking into consideration social, environmental and ecological issues. Plans were produced for consultation, design and to support regulatory consent applications.
Structural design (geotechnical investigations, earthworks, bridges, culverts and retaining walls)
Specific structural forms, bridge spans and earthwork designs were refined and improved in order to avoid, remedy or mitigate any potential adverse effects. This work ensured that a top quality design was produced, including maximising route security against seismic events.
Transportation and traffic impacts
Consultants assessed the wider road network and how Transmission Gully would affect it. The findings of the transport modelling work assisted the other technical assessments to produce an integrated assessment of the overall effects of Transmission Gully.
Hydrology and stormwater control
Erosion, sediment controls, and stormwater design were studied to better understand the streams and coastal environment. Controls and designs were developed to manage effects of the highway both during and after construction.
Landscape and visual impacts
The visual impacts of the project have been assessed and suitable design treatments developed to avoid, remedy or mitigate adverse effects for road users and adjacent property owners. An integrated approach to the urban and road design has been adopted.
Ecological effects
The team undertook a full ecological effects assessment for all affected waterways, including stream surveys and ecological valuation, in order to propose measures and treatments to avoid, remedy or mitigate these effects. Extensive flora and fauna surveys have also been undertaken, including birds, lizards, snails and native vegetation.
Urban design
An urban and landscape design framework document has been developed in consultation with key stakeholders to define the urban and landscape design concepts for the project. This will be inputted into the detailed design, and will be a key driver in achieving a good visual outcome.
Noise and vibration
An assessment of the effect of road noise on communities and properties along the route, including ambient noise measurements, and modelling of construction and operational noise has been completed. The construction methods likely to be used, and associated noise and vibration have been assessed. A noise management plan has also been developed to determine the best ways to manage those effects.
Air quality
Consultants have produced an assessment to determine effects on air quality. This assessment enabled consultants to understand the wider air quality benefits Transmission Gully brings to other communities.
Water quality
The streams and water catchments include areas of high ecological value. The quality of water before, during and after construction has been assessed, and measures developed to avoid or reduce any potential effects on streams and the coastal environment.
Utilisation of physical resources
The design and construction methods have been constantly tested to improve the utilisation of physical resources and reduce the emission of greenhouse gases.
Contaminated land
As part of the technical assessment, historical data and site investigations have been used to identify potential areas of existing contaminated land that, if disturbed, could be harmful to people, ecological health, air and water quality. Suitable treatment plans have been developed to manage effects.
Social impact, community cohesion and health
The team has examined the potential social impacts and wider benefits associated with the project. These have been considered particularly in relation to the location of new connections, and methods to connect communities across the route.
Culture and heritage
The NZTA has undertaken an archaeological assessment, consideration of architecture with historic background that merits preservation, and an assessment of iwi cultural impacts.
Land use and transport integration
An assessment of how the Transmission Gully project fits in relation to local land use planning and the interface between land use and transport has been undertaken as a key part of the assessment of effects.
Porirua City Council selects routes for link roads
The Porirua City Council has selected the preferred routes for the two link roads from Whitby and Waitangirua to the Transmission Gully highway after considering various options together with submissions received from a public consultation process.
The link roads to James Cook Drive and Warspite Avenue/Niagara Street will be part of the Council's local road network and have been designed to local road standards, for a 50km/h operating speed with no section steeper than a grade of 1:10.
At the Warspite Avenue/Niagara Street intersection, a new roundabout is proposed with sufficient land reserved for traffic signals and the possible future extension of Niagara Street as a link to Whitford Brown Avenue.
Where zoning permits future residential development beside the link roads, the designation sought will allow for future footpaths, kerbside parking, entrance splays for residential roads and necessary services.
The Council is lodging its required regulatory consents with the Environmental Protection Authority (EPA) jointly with the NZTA, with the NZTA being the applicant for regulatory consents for the Transmission Gully route and the Council being the applicant for the Whitby/Waitangirua link roads.
Property matters
The NZTA has been contacting landowners directly to talk to them about the possible impact the Transmission Gully route might have on their properties. This engagement has been on-going since the investigative phase of the Transmission Gully project.
Where the Government is acquiring any property for a public work, it is a basic principle of compensation that an owner shall be entitled to fair and reasonable compensation for the losses that may occur. When acquiring land from an owner, the NZTA engages an independent Land Information NZ accredited agent to be sure the compensation process is transparent and fair.
All Transmission Gully Project property issues are being managed in compliance with the Land Information NZ guidelines for acquiring property under the Public Works Act 1981.
- View a copy of the Land Information NZ guidelines (external link)
For any enquiries regarding property issues related to the Transmission Gully Project, please call 0800 TG INFO (0800 844 636)
