Waitemata Harbour Crossing Study - Phase 2

2 May, 2008

A joint project between Auckland City Council, Auckland Regional Council, Auckland Regional Transport Authority, North Shore City Council and Transit New Zealand to identify a preferred option for an additional  transport link across the Waitemata Harbour

Executive Summary
Map - preferred route Phase 2                                                                                                                                                                                                                      
SH1, electric trains under the Waitemata seabed?

The latest thinking in a study on another major crossing of the Waitemata Harbour sees the suburban electric rail network and State Highway 1 extending beneath the seabed in tunnels to connect the North Shore with the Auckland CBD and beyond.

The Waitemata Crossing Study team has today released a summary of the consultant’s report recommending a preferred route, having narrowed a long-list of 159 options to a short-list of three late last year.

The recommended option comprises four tunnels – two for trains and two for the motorway - east of Auckland Harbour Bridge.  The Central Motorway Junction on the isthmus would link to the Northern Motorway, while the suburban rail network could in future be extended northward from the Auckland central business district to the North Shore.

The study was commissioned last year so steps could be taken to safeguard a future transport corridor, if necessary, before the Wynyard Quarter was redeveloped.

It has concluded that the use of driven tunnels gives the region flexibility as to the route and timing of project components, and future-proofs links with major transport infrastructural projects such as the CBD loop rail tunnel.

The rail connection from the north would run in deep tunnels east-west under the Wynyard Quarter which would be served by an underground rail station.  The motorway tunnels would largely bypass the precinct on its south-western corner.

By the end of May the recommendations of the full report will have been formally considered by each of the study’s partners; Transit New Zealand, the Auckland Regional Council, Auckland City Council, North Shore City Council and the Auckland Regional Transport Authority.

The study did not canvass when a crossing might be built, or how it would be funded.

The recommended option
The cross-harbour tunnels would run underground just south of the Onewa Road interchange on the North Shore and reach the isthmus at depth under Westhaven Marina.

The rail tunnels (one track northbound, one southbound) would then travel eastward under Gaunt Street to link with a future CBD loop rail tunnel.  There would be an underground station in Gaunt Street, between Daldy and Halsey Streets, to serve the Wynyard Quarter.

The twin motorway tunnels would form a new section of State Highway 1, with six lanes of general traffic (three northbound, three southbound).  From Westhaven, the motorway would pass under Victoria Park before surfacing to link to the Southern and Northwestern motorways within the Central Motorway Junction.

Pedestrians and cyclists would be accommodated on the existing harbour bridge, which would continue to carry general traffic to Ponsonby and the CBD, but would cease to connect with the Southern Motorway.  The Victoria Park flyover would be demolished.

The estimated cost of the package is $3.7 billion to $4.1 billion.

A new crossing creates greater capacity, resilience and flexibility within the transport network.

The study says that an 80% increase in person trips across the harbour is forecast by 2041.  Currently about 26,000 people cross the harbour southbound in the morning two-hour peak period.

The study identifies passenger transport as having the most potential for increasing capacity.  By 2041, passenger transport would cater for about 30% of trips, up from the present 15%.

An additional crossing on its own does not markedly diminish forecast road congestion levels.  There would still be delays and queues at peak travel times.

The creation of a new route to carry the bulk of SH1 traffic offers flexibility for the transport system to evolve over time and maximise benefits of infrastructural investment.  The existing harbour bridge, for example, could be used to extend the Northern Busway into the CBD, or the bridge ‘clip on’ lanes could be removed altogether if that ever became necessary.

Rail and road components could be built at different times, if required.

The northern approaches in a nutshell

• Both rail and road approach the harbour from the north on reclaimed land or on a structure at approximately the same level as the existing carriageway of the Northern Motorway (between Esmonde and Onewa Roads).
• The cross-harbour driven tunnels (four separate bores) begin south of Onewa Road.
• There could be road connections to the new crossing at Akoranga Drive, Fred Thomas Drive and Onewa Road.

Cityside connections in a nutshell

• Rail tunnels travel under Gaunt Street to link with a future CBD loop rail tunnel, and therefore through to the suburban rail network (existing and future extensions).
• Motorway tunnels reach ‘cut and cover’ tunnels under Victoria Park, bringing motorway traffic to the surface, with tunnel portals south of Cook Street (within the existing motorway corridor).
• Southbound traffic from the harbour bridge exits at Ponsonby, and Fanshawe and Cook Streets.
• The already proposed Victoria Park Tunnel links northbound traffic from the Wellington Street on-ramp to the bridge.
• A new ‘cut and cover’ tunnel under Victoria Park links southbound traffic from the bridge to Cook Street.

Changes in thinking
The recommended route is a variation on the Esmonde Rd-Wynyard Point route short-listed late last year.  The main developments in thinking since then are:

• Driven tunnels are much less disruptive than a bridge or ‘cut and cover’ tunnels.
• The ability for the suburban electric rail to cross the harbour in future should be preserved because it provides greater regional connectivity, and greater capacity than buses.
• Disruption at Wynyard Point, which is about to be redeveloped, can largely be avoided (though the rail tunnel alignment and station site would need to be protected for future construction).
• A vehicular crossing provides more regional connections and economic benefits than a crossing dedicated only to buses or trains.

A Grafton Gully connection
After the Westhaven-Onewa alignment, the next best performing option is a series of long tunnels (two motorway, two rail), with vehicular traffic linking to the Southern and Northwestern motorway at Grafton Gully (east of the CBD).

The rail tunnels would diverge from the more eastern road alignment under the harbour at a point east of Princes Wharf, and reach the isthmus at depth under Albert Street and link to a future CBD loop rail tunnel.

This option is more expensive and complex to build.  The estimated cost is $4.7 to $5.1 billion.

However, the study notes that even if the motorway went to Grafton Gully, rail could take the Onewa-Westhaven route in order to provide the economic and transport benefits associated with a rail station at Wynyard.

The Grafton Gully option is the best place to bring north and southbound traffic into the motorway network, as it would connect with the Southern Motorway south of the Central Motorway Junction.  It may also offer opportunities for urban renewal in the Beach Road area, where there would need to be extensive demolition during construction.

Bridge not recommended
The study says a wide-decked bridge could carry general traffic, trains and pedestrians/cyclists on the Onewa-Westhaven route.

A bridge would technically be the easiest to build, and less expensive, but is not a recommended option as it would be the most socially and environmentally disruptive to the CBD waterfront and St Mary’s Bay.  The main loss would be the Westhaven marine precinct, at least in the form it is known today.

 Background

Phase one of the study, that concluded in November, proposed a short-list of priorities for further investigation.  These included variations on three options:

• A crossing for only passenger transport between the North Shore and the western CBD.
• A crossing for vehicles and passenger transport between SH1 (at Esmonde Road) on the North Shore to the western CBD.
• A tunnel linking SH1 (at Esmonde Road) on the North Shore to the eastern CBD.

Options that did not make the short-list:

• Crossings west of the existing bridge did not create a strong public transport connection with the CBD. This helped eliminate Te Atatu, Rosebank, Waterview, Pt Chevalier, Meola and Western Springs.
• Bayswater/Stanley Point, and the wider Devonport peninsula, are not identified as growth nodes in the Regional Growth Strategy and any crossing connecting to those locations would have major adverse social effects.
• A route through the middle of Shoal Bay, Northcote Point had the most adverse environmental impacts.
• A crossing to Resolution Point (near the Parnell Baths) would create severance issues between the CBD and Tamaki Drive and be a more expensive, longer crossing option.
• Tunnelling a connection through to Panmure /Glen Innes would have significant adverse environmental effects and the highest cost.
• A crossing to Highbury (Glenfield Road) had high adverse social effects and cost.
• A bridge to the east of the CBD is unrealistic because of the required height clearance for ships.
• Simply crossing the harbour from edge to edge isn't enough - connections to the wider road network were stronger at Esmonde, Wynyard and Grafton than from crossings to Onewa, Westhaven, Queens Wharf or Tamaki Drive.

The shortlist was developed from an original list of some 159 options, taken from all the major investigations that have been carried out since 1997, plus other options identified by the study partners and suggestions made by members of the public.

The study team, including representatives of each project partner, worked together to evaluate each option against the objective of delivering integrated, safe, responsive and sustainable cross harbour travel between the North Shore and the isthmus to support the planned growth of the Auckland region.  All transport types were considered including bus, rail, heavy vehicles, cars, cyclists and pedestrian access.

The shortlisted options were those that best met the objectives of:

• Economic development and regional growth – in line with the Regional Growth Strategy.
• Connectivity – creating connections between transport networks.
• Environmental – sustainability and effects on the natural and built environment.
• Social and community – connecting communities and avoiding severance and displacement.
• Affordability.
•  

Issues shaping the project include:

• Supporting planned growth in the region.
• Providing more transport options across the harbour for passenger transport, cycling and walking.
• The need to identify and protect a corridor for an additional crossing, particularly in view of the development planned for Auckland’s waterfront.
• Creating an additional strategic option to the Auckland Harbour Bridge, already carrying more than 160,000 vehicles per day (nearly 60 million vehicles a year).
• Managing traffic flow between the North Shore and Auckland.
• The need to provide certainty for communities who may be affected by another crossing.

This second phase of the study has narrowed the shortlist to a single, preferred option. This enables the region to protect a route while progressing development plans for the CBD’s waterfront.

ENDS

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