New Zealand’s largest roading project is well underway. When completed, it will connect the Northwestern and Southwestern motorways at Waterview and allow Aucklanders to get around, and out of, the city more quickly
As a new Spaghetti Junction rises above Waterview, contractors are also toiling on a $500 million slew of related motorway projects to add flesh to the long-awaited western ring route.
And while a mega-machine called Alice burrows unseen on a different heading - from Waterview to Owairaka tocomplete a 2.4km pair of tunnels - little is hidden from motorists' eyes of efforts across a massive canvas along the Northwestern Motorway.
Earthworks are being undertaken on a monumental scale to widen and raise the 4.8km marine causeway which has been traversed by commuters since 1952.
Also in the public gaze are motorway widening projects from Waterview back to Western Springs, and from the far end of the causeway at Te Atatu to Henderson, as well as upgrades to four existing traffic interchanges along a sprawling 10km worksite.
The Transport Agency says completion of those projects and the $1.4 billion link through the Waterview tunnels will mean the ring route being "substantially done" by 2017. Full completion is expected by 2021.
Here is an update on progress so far:
Northwestern Motorway widening: Projects in progress
(10km from Western Springs to Henderson)
CAUSEWAY UPGRADE
Northwestern Motorway Causeway, towards Waterview Interchange and Auckland CBD, Northwestern Motorway. Photo / Brett Phibbs
Cost: $220 million Started: May 2013 Expected completion: Late 2016 Distance being widened: 4.8km
• Waterview to Rosebank Rd - to increase from three lanes each way to five general traffic lanes westbound and four lanes citybound, with a bus shoulder on each side.
• Rosebank Rd to Te Atatu - from three general traffic lanes to four lanes and a bus shoulder each way.
What it involves:
• Widening the 63-year-old causeway from Waterview to the Te Atatu side of the Whau River from about 50m to 66m, with slight variations between sections, while building it up by 1.5 metres to recover from past ground settlement and to protect against sea levels rises over the next 50 years.
• Tying in the upgraded causeway to the new three-level Waterview motorway-to-motorway junction.
• Doubling the width of two causeway bridges - a 75m bridge across the Waterview Estuary channel to the Waitemata Harbour and a 182m bridge across the Whau River.
• Upgrading a traffic interchange at Patiki Rd, where a short westbound motorway on-ramp bridge has been built for cyclists and walkers to pass below.
• Upgrading the Northwestern Cycleway parallel to the causeway to a 3m shared walking and biking path - including two wider sections for seating and information signage.
• Creating drainage filters and swales to treat stormwater run-off from the causeway into the Motu Manawa-Pollen Island Marine Reserve, for the first time.
• Earthworks: About 500,000 tonnes for bulk fill and a similar amount again for pavement construction - includes brown rock, clay, pumice sand, road aggregates, coastal protection rock and asphalt.
• The fill is being laid after the removal of 26,000 truckloads of quarry stone loaded on to the northern side of the causeway and left for most of last year to squeeze out water from deep marine sediment through 10,000 vertical wick drains.
Proportion completed: About two-thirds.
WATERVIEW TO WESTERN SPRINGS
St Lukes Interchange, on the Northwestern Motorway. Photo / Brett Phibbs
Cost: $50 million Started: May 2014 Expected completion: March 2016
What it involves:
• Widening 2km of motorway from three to four traffic lanes each way.
• New interchange bridge 5.5m above motorway from St Lukes Rd to Western Springs, twice as wide as the old one it is replacing, with three traffic lanes and shared cycle-foot paths each way.
Strategic importance of upgraded interchange:
• Last entrance point to the motorway from the city before the Waterview tunnels.
Progress:
• First half of the new bridge completed, and being used by traffic.
• Old bridge has been demolished and preparations have begun to build the second half of the new structure.
Te Atatu interchange, Northwestern Motorway. Photo / Brett Phibbs
Cost: $58m Started: February, 2014 Estimated completion: January 2017
What it involves:
• Widening 1.5km of motorway from Whau River to Henderson Creek (to four lanes plus a bus shoulder each way from the river to the interchange, and to three lanes to the creek)
• Raising three existing interchange bridges (two for motor vehicles and the other for pedestrians) by 600mm to provide a 5.1m clearance for motorway traffic;
• Adding a new pedestrian bridge across the motorway on the eastern side.
• Building a pedestrian and cycling underpass parallel to the motorway beneath Te Atatu Rd.
Progress: 75 per cent complete.
LINCOLN RD INTERCHANGE UPGRADE
Lincoln Road interchange, Northwestern Motorway. Photo / Brett Phibbs
Cost: $145 million Started: November 2010 Estimated completion: December 2015
What it involves:
• Building a new interchange bridge 5.25m over the motorway with three traffic lanes in each direction and a footpath on the western side (compared with one traffic lane each way on the old bridge it has replaced).
• Realigning and rebuilding four motorway entry and exit ramps.
• Widening 1.5km of motorway from Henderson Creek to the western side of the interchange - from two to three traffic lanes and a bus shoulder each way.
• Building wider motorway bridge across Henderson Creek.
• Upgrade of shared pedestrian and cycling path beside the motorway.
Progress:
• Overall project 96 per cent complete.
• Interchange complete apart from final pavement surfacing.
Cost: $1.4 billion Started: January 2012 Estimated completion: March 2017
What it involves:
• 4.8km link for three lanes of traffic each way between the Southwestern and Northwestern Motorways, 2.4km of which will be through twin tunnels.
• Three-deck motorway-to-motorway interchange at Waterview, with four ramps of a combined length of 1.7km, the highest of which will tower 23m above the ground.
• First tunnel completed and boring machine more than a quarter its way through drilling the second tunnel - due for breakthough back at Owairaka in about September.
• Two interchange ramps completed; Third and highest one has bridged the Northwestern Motorway, although faulty concrete is having to be cut from one section at the supplier's expense.
