The first of the Northern Corridor projects to get underway, the southern section of the 33-kilometre Kāpiti Expressway is scheduled for completion mid 2017. This encompasses a $630 million, 18-kilometre, four-lane lane highway from MacKay’s Crossing north of Paekākāariki to Peka Peka.
It will separate local and highway traffic, avoiding traffic lights and congestion by passing above or around the built up urban areas of Raumati, Paraparaumu and Waikanae, which will connect to the expressway via local roads. An end-to-end, three-metre wide shared pathway next to the expressway will accommodate pedestrians, cyclists and horses.
Two traffic lanes in each direction will be separated by a median safety barrier, with 18 new bridges being constructed, the largest of which at 180 metres will be a new crossing over the Waikanae River. All have been designed to withstand the combined effects of large (one-in-2500 years) earthquakes and liquefaction, with the piles of the Waikanae Bridge being up to 40 metres deep.
NZTA says many learnings from the Christchurch earthquakes, as well as international seismic design standards, have been considered and work has included a range of engineering techniques to provide seismic resilience including strengthening and compacting the ground as well as using concrete lattices to interlock bridge piles.
Environmental protection and enhancement will include 140 hectares of new planting and landscaping, the creation of 9.5 hectares of new or restored wetlands, some of which will provide for stormwater retention, and 1.4 million locally sourced indigenous plants. Along with engineered wetlands, swales have been constructed on either side of the expressway to cope with rainfall run-off and to withstand a 1-in-100 year flood.
This section of the Northern Corridor is being built by the M2PP Alliance comprising the NZTA, contractors Fletcher Construction and Higgins Group and engineering consultancy Beca supported by Incite, Boffa Miskell and local company Goodman Contractorswhich is doing most of the earthworks for this project and Transmission Gully as well. The Kāpiti Coast District Council (KCD) is a non-commercial partner in the alliance.
Despite wet and cold conditions over winter those involved are reported to be “rejoicing over the phenomenal progress” according to Contractor magazine. John Palm, the M2PP Alliance’s construction manager, says the project has progressed very well with the focus over the summer months being on completing the earthworks and bridges, getting the bulk of the pavement down, constructing culverts and kerbing and continuing with the planting programme. Later in the year two kilometres of existing highway north of MacKay’s Crossing that has suffered sinkage undulations and surface deterioration will be rehabilitated.
This expressway project is one of the first to include a council body as part of an alliance and has, according to John Palm, brought about a partnering attitude and collaboration between KCDC and the developers.
“In particular, the council allowed us to work through changes in consents and provided a ‘heads-up’ on pending issues that have impacted on various communities and individuals,” says Palm.
The expressway will run close by the entrance to the expanding Kāpiti Coast Airport at Paraparaumu, which now has daily Air New Zealand flights from and to Auckland and Christchurch. The adjoining 125-hectare Kāpiti Landing business park, which Todd Property is developing, has resource consent for approximately 300,000m2 of commercial, retail and industrial space.
To date, development has largely been focused on bulk retail premises servicing a growing surrounding residential catchment. However, longer term, given its proximity to both the airport and the new motorway, Kāpiti Landing has the potential to become a major regional commercial and industrial business hub.
Simon Bridges says the Kāpiti Expressway has provided a big boost to the local Kāpiti economy. “Over half of the contractors’ spending for suppliers and subcontractors to date has been with local Kāpiti businesses. Nearly 600 people are employed on the project and this doesn’t count the jobs that have been created with suppliers and through local businesses. The project is kick-starting careers and fostering an enduring skill base for the region through a partnership with Whitireia and Weltec to recruit local graduates.”
Providing further impetus to the Kāpiti economy will be the second stage of the expressway from Peka Peka to Ōtaki on which much of the design work has been completed and construction is scheduled to start by the middle of this year. The 15-kilometre four-lane, median-divided highway will run along the existing SH1 route to Te Horo, with a bypass on the eastern side of Ōtaki. It is scheduled for completion in 2020, around the same time as Transmission Gully.
The final northern leg of the corridor encompassing a further 30 kilometres from Ōtaki to Levin will involve an upgrade of existing roading rather than a new expressway. The initial focus has been on immediate changes needed to improve safety and traffic efficiencies on parts of the route ahead of the long-term plan to create a four-lane highway as far north as the SH1/SH57 intersection. This will be undertaken on a staged basis with more detailed design to be done over the next two years with a view to getting construction underway in 2019.