Kia ora and welcome to the February 2018 update from the Transmission Gully team.
An articulated dump truck unloading boulders beside State Highway 1 at Paekakariki.
Four articulated dump trucks, running in convoy, worked through the day to haul boulders from Transmission Gully motorway’s site at Paekakariki to a section of State Highway 1 hit by cyclone Gita.
CPB HEB JV Project Director, Boyd Knights, says when the call came in from NZ Transport Agency to help build a seawall for a section of State Highway 1 near Paekakariki, damaged by Cyclone Gita, it was a no brainer.
“We’ve got a large community of people surrounding the project, so it was great to step in and do what we could to help out,” he says.
Cyclone Gita, which hit Wellington late on Tuesday 20 February, wreaked havoc overnight, with a section of embankment along State Highway 1 between Pukerua Bay and Paekakariki washed away by the sea.
Four articulated dump trucks, each loaded with between 30-40 tonnes of boulders set off on the hour-long return trip from the site compound at Paekakariki. By Wednesday afternoon, the team had delivered around 350 tonnes of boulders to stabilise the affected area and protect it from further damage from the sea.
“The team did a great job working alongside the Transport Agency’s network maintenance contractors to get the boulders in place for the damaged section of State Highway 1 before high tide, so they could get a lane open before peak traffic hit,” says Boyd.
Once the evening commute had passed, the team worked through the night to get both lanes open before sunrise on Thursday morning.
“It’s weather events like this that keeps us focussed on getting the new motorway built. Once it’s finished, it’ll provide another route between Wellington and the lower and central North Island that’s safer and more reliable for motorists, and better able to resist and recover from earthquakes and storms.”
Senior Journeys Manager for the Transport Agency, Neil Walker expressed thanks to the Joint Venture team for their efforts. “It was lucky the Transmission Gully team was there with boulders and equipment to get the repair done so quickly.”
Taking a moment after the blessings are (from left) CPB HEB JV Environmental and Stakeholder Manager Darren Utting, CPB HEB JV Senior Environmental Advisor Reuben Mills, Ngāti Toa kui Roena Parai-McCarthy, Ngāti Toa kaumatua Taku Parai, Ngāti Toa kui Jane Edwards, CPB HEB JV Ngāti Toa employee Ezra Metekingi, CPB HEB JV Ngāti Toa employee Jensen Parata and CPB HEB JV Supervisor Hamish Croad.
On Friday 8 February, two whakapainga (blessings) were performed for two sections of water now flowing in the Te Puka and Horokiri permanent stream channels.
Led by Ngāti Toa’s elders and kaumatua, Taku Parai, members of the project team in attendance were taken on a journey of cultural significance.
Te Rūnanga O Toa Rangātira Chairperson Te Taku Parai said Transmission Gully traverses an area of high cultural significance to Ngāti Toa, especially the Wainui Saddle and the Horokiri Valley.
“Traditionally the forest, streams and harbours of the area were used extensively by Ngāti Toa for gathering kai (food), including fish and birds, and other essential resources, such as native plants for rongoa (medicine) and timber for building whare (houses) and waka (canoes),” he says.
The areas are taonga (sacred) to the iwi, and it was important to recongnise the past, and ensure that the sustainable management of the environment within their rohe continues to be promoted in the future.
He spoke of acknowledging their ancestors, Papatūānuku (sky father) and Ranginui (earth mother) and their many children, who gave birth to more children, including birds, fish, winds, and water. They became the ancestors of all life and all natural phenomena. “All things of this world are descendants of the children of Ranginui and Papatūānuku, and all life is interconnected,” says Taku.
“Ranginui is a powerful figure, as she represents the generative foundation of all life. All things are born from her and nurtured by her, this includes Te Puka and Horokiri streams.”
The blessing finished with a karakia (prayer) to lift the tapu, and to allow works to move forward for the two streams.
Attendees were then invited back to the site office, based at Paekakariki for a barbeque with over 100 workers involved in the earthworks and stream construction.
Wellington Gateway Partnership Chief Executive, Sergio Mejia, says that Ngāti Toa Rangatira are kaitiaki (guardians) for the project. “We work closely with them on a range of areas covered by construction of the Transmission Gully motorway. This includes providing cultural advice, environmental monitoring, and archaeological monitoring.
“We also have a Memorandum of Understanding with Ngāti Toa Rangatira to promote and support education, training, employment opportunities and kaitiakitanga.”
Marked a feat of environmental engineering, the diversion work requires sections of Te Puka Stream to be shifted sideways and up to 20 metres above its current position to allow for the new motorway route.
CPB HEB JV Project Director Boyd Knights says that 1.7 kilometres of Te Puka Stream had to be raised because the valley floor needed to be higher for the motorway. “It’s a ‘one of a kind design’ and ‘very difficult’, not least because access for workers is narrow and steep, temporary diversions are required to protect the stream during construction, fill had to be brought in from elsewhere on the project and the finsihed waterway needs to meander as streams do.
“The 2.4 kilometre Horokiri Stream is a wider and shallower waterway than Te Puka Stream and has different requirements. Each stream has been specifically designed to most closely mimic the natural watercourse we are replacing,” says Boyd.
After the new streambeds are constructed, they can follow a natural course, with their banks densely planted in native shrubs and trees and the new streams restocked with native fish. The fish were relocated from the streams prior to construction starting, in one of the largest fish relocation exercises in the country. With this restocking and revegetation, it is expected that valleys such as Te Puka will eventually be richer in wildlife than before the project started.
“We love the challenge, with engineers and environmentalists coming together to recreate what nature has built.”
The Transmission Gully motorway has more than a kilometre of bridges and underpasses along its 27 kilometre route. A total of 25 structures are being built, but many of these don’t have such obvious names as Cannons Creek bridge, so we use numbers to identify them.
Check out the map below to see all of the bridges, by number, and where they’re located along the Transmission Gully motorway route.
View larger image [PDF, 2.6 MB]
In early February we reached the milestone of five million cubic metres of earth moved since construction started. Here’s the latest from the team on what’s been happening across the Transmission Gully project in the last month, and what’s coming up.
An example of a keystone RE wall, which has concrete cruciform panels.
At the northern end of the project, the new section of Coast Road is now built up to subgrade level, which is the final level of earthworks before construction of the road surface starts. The first section of road sealing is scheduled to start in early March.
Between Paekakariki and Mackays Crossing we’re making changes to the road layout to provide safe working areas for our construction team to extend an existing culvert under SH1. These changes include the narrowing of lanes and a change to where we enter and exit our site.
We’ve also started construction of the keystone retaining walls for the bridge that will provide access under the new motorway for some Paekakariki residents (Bridge 2). These retaining walls are sometimes referred to as RE (reinforced earth) or MSE (mechanically stabilised earth) walls. MSE walls have a distinctive modular block system, whereas keystone RE walls have concrete “cruciform” shaped panels. MSE and RE walls use similar construction methods, with layers of earth strengthened by reinforced grids behind the face of the wall.
For another of our bridges (Bridge 3), which will cross over the Te Puka Stream, we’ve started the pioneering works down to the streambed and construction is underway on the bridge footings.
An example of a MSE wall, which is a modular block system.
Near the Wainui Saddle, bulk earthworks remains a focus, with teams working in shifts, 24 hours a day, seven days a week.
The permanent diversion works for the Te Puka Stream are progressing well, with 700 metres of the stream now flowing in its permanent channel. This milestone was recently celebrated with a blessing undertaken by Ngāti Toa’s kaumatua.
View looking north over Te Puka Stream permanent diversion works underway.
View of Bridge 6 with both abutments now complete.
Preparation works have started on the foundations for one of the bridges over Horokiri Stream (Bridge 4). An underpass to provide access for landowners (Bridge 5) is complete. RE walls are now complete for another bridge that crosses over Horokiri Stream (Bridge 6), with installation of the beams set to take place in March.
Horokiri Stream diversion works are well underway, with 800 metres of the stream now flowing into its permanent channel. This milestone was also marked by a blessing undertaken by Ngāti Toa’s kaumatua.
The area through Battle Hill Farm Forest Park either side of the public underpass (Bridge 7) is now up to subgrade level and road pavement construction has commenced.
A section of Horokiri Stream permanent channel under construction. Rocks are placed on a concrete base to protect the liner from damage by boulders.
From our site compound at Paekakariki Hill Road, heading south to the top of Flightys Road, detailed earthworks are ongoing. Detailed earthworks are the pioneering works, which include clearing vegetation, building access tracks, and building erosion and sediment controls, in preparation for bulk earthworks - like that being done by heavy-duty scrapers and articulated dump trucks through Battle Hill Farm Forest Park and south around Whitby.
The access road is now fully connected from our Paekakariki Hill Road compound to State Highway 58, but is not quite ready for use by our heavy machinery.
The gas pipeline relocation near the Pauatahanui Golf Course to the site entrance on Paekakariki Hill Road is on track to go live in March.
An underpass for private landowners is being constructed in this area (Bridge 11), and we’re preparing the area for works to start shortly on the foundations.
Another underpass for residents near the top of Flightys Road (Bridge 12) is now complete. Soon we’ll begin construction of the wing walls either side to build the level of the road up and over the top.
New power poles being installed at Lanes Flat in preparation for the new section of road.
Construction of the new section of road for State Highway 58 and the interchange bridges is progressing well, with much of the area now built up to subgrade level. Towards the end of this year traffic will be switched to this new section of road so our teams can complete construction of the interchange. We’ll keep you updated as these works progress and what to expect leading up to the switch over.
Power lines running through our site compound at Lanes Flat are being relocated in preparation for the new section of road and will soon be made live.
View looking north of bulk earthworks underway near Belmont Regional Park.
Through this area bulk earthworks remains the focus for the construction team.
There are a number of bridges through this area, including a future underpass to allow users of Belmont Regional Park safe access under the motorway. The base slab for this underpass (Bridge 18A) has been poured, however, it won’t be open for public use until the motorway is complete in 2020.
Construction of a bridge over Duck Creek (Bridge 19) is progressing well, with bulk fill for the RE walls underway.
View of the launch yard, where the majority of the temporary concrete bases for the girder assembly have been constructed.
Pier excavation work is now complete and back fill concrete pouring works are well underway. Both piers require more than 7,000 cubic metres of concrete. So far we’ve poured 1,595 cubic metres for pier one, and 505 cubic metres for pier two.
Construction of the bridge launch yard is on schedule to be complete for the delivery of the first of the large steel girders, which are due to arrive from Napier in April.
Further south, the section of alignment from Cannons Creek to Ranui Heights is nearly up to subgrade level.
Looking north-east over a section of the alignment close to subgrade level at Linden.
Pioneering works continue for the Porirua link roads.
The focus for the construction team remains on pioneering works, including clearing vegetation, creating access tracks and building erosion and sediment controls. Around ten percent of the earthworks for the two link roads has been completed.
We’re working with the local marae to move a significant tree on the grounds, and a pohutukawa tree that needs to be moved to make way for the road.
At the southern end of the project, construction of the northbound on-ramp for the new motorway is well underway beside Tremewan Street. The columns for this bridge (Bridge 25) are clearly visible on either side of State Highway 1.
Bridge 25, Abutment A RE embankment construction underway.
We’ve also had people ask why the temporary speed limit heading northbound on State Highway 1 near Linden is 70 km/h. This is because of the temporary layout of the road. The area needed to be designed to allow for the two northbound lanes, as well as the construction of the bridge piers, which resulted in the tighter temporary curves in the road that restrict the forward sight distance for motorists. Any obstruction on the road length needs to be visible to the driver from some distance away to allow time to stop or to take preventative action. Reducing the speed limit to 70km/h allows road users to safely travel through this area despite the temporarily reduced sight distance.
The southbound lanes don’t have these sight distance restrictions, so the temporary speed limit can remain at 80km/h, which is the safest speed to travel at with the narrowed lanes.
Works on the first section of the new Collins Avenue bridge (Bridge 26) are on track for southbound traffic to be moved onto the new bridge in the middle of the year. Works will then start to demolish the old southbound bridge, before the middle section of the new bridge can be built. We’ll keep you updated on these works as they progress, and what to expect closer to the time.
View looking down on Collins Avenue bridge, where the first new section is in its final stages of construction.
We’re also working hard on the Kenepuru Interchange, where there will be a roundabout close to the current entrance to North City Tenpin Bowling Alley. A number of MSE walls will be built in this area to connect the new roundabout to the bridge that is now in place over the Kenepuru Stream and the North Island Main Trunk (NIMT) railway line.
A section of the pathway between Kenepuru and Porirua Stations will be closed for a short time over Easter (30 March to 2 April inclusive) so we can lift a set of bridge deck panels over the NIMT railway line. We’ll have signs in place closer to the time and pathway users will need to use the alternative route along Kenepuru Drive.
We’d like to remind the public to stay away from our construction areas for their safety
Some of these works are highly dangerous and despite the many safety warnings, people are continuing to enter the construction areas. We have very large machinery working and the operator’s vision is sometimes very limited. They’re concentrating on their job, and not expecting, or looking out for people.
We have extensive safety procedures in place to keep our staff safe, but unauthorised people who don’t follow those procedures are putting themselves at extreme risk. Please observe all signs and do not enter these construction areas under any circumstances. To view how work is progressing, check out our website at www.tg.co.nz for recent photographs, videos and drone footage.
The project has one of the largest replanting programmes by a construction project in New Zealand. One million native trees and shrubs are being planted over the coming year, that’s half of the total to be planted for the project.
250,000 Kanuka being propagated in a Taupo native nursery are just some of the one million native trees set to be planted this year for the project.
Around 534 hectares of land surrounding the new motorway is being fenced off from adjacent land use and planted with around two million native trees and shrubs, including seedlings of long-living tree giants like totara, matai and rimu, aiming to create one of the most significant lowland bush areas in the Wellington region. Streams along the 27 kilometre project length are also being enriched with riparian planting to create a better environment for native fish and birds.
CPB HEB JVs Environmental Manager Darren Utting says advanced planting took place ten years ago and the success of this has guided the final planting plan.
“Everyone involved is taking it step-by-step, for example with the trials over a decade ago to see where podocarp tree seedlings grew best,” Darren says. “The stereotype is that Wellington’s southerly wind can be pretty harsh, but it doesn’t seem to apply here. We’ve found podocarps are more likely to thrive on the southern sides of ridges and spurs, because the prevailing wind actually comes from the north.
“Young native forest will take many years to fully develop and after initial planting the forest will rely on natural regeneration,” says Darren.
‘Pioneer’ species of smaller trees and shrubs are being planted first, to create windbreaks for longer growing tree seedlings. All seeds have been ‘eco-sourced’ from Wellington, the Kāpiti Coast and the Akatarawa Ranges; in other words they’re local species, including from the Transmission Gully motorway route.
“We had people walking through and picking seeds by hand, many of which are now growing in nurseries. Seedlings have their own barcodes, based on where they’re sourced, so we can track the plants to see what grows and thrives where. We’ve also had to source extra seeds from outside the route because the range of species still surviving in patches of bush is much smaller than would have been there originally,” says Darren.
With the increased habitat, it’s hoped that iconic song-birds like tui and bellbirds would successfully nest in the new bush and rarer species like native falcon or kārearea would migrate from the Tararua, Rimutaka and Akatarawa Ranges and kākā to and from the likes of Kāpiti Island.
Darren says another community planting day is being planned for the middle of this year. “We’ll let people know more about this once details are confirmed.”
Northern Environmental Manager, Reece Wilkie, couldn’t believe what he was seeing when he was called to help an unusual visitor in the staff car park at Lanes Flat, on a wet and windy Thursday afternoon in February.
“I was told there was a seal in the carpark, and I thought they must be having me on. I went out to the carpark and looked, and sure enough, there was a New Zealand fur seal pup, sitting in the middle of the carpark, looking very lost.”
Reece believes the seal pup made it’s way up the Pauatahanui Stream during heavy rain earlier that day, and came ashore beside the main site entrance.
“It had quite the adventure for such a young pup, managing to navigate it’s way through a very busy construction site and across the main driveway to the back car park,” says Reece.
Reece, who has a background as an animal handler, knew this was going to be an interesting rescue. Hailing from Australia, he spent five years as an ecologist capturing and measuring a number of wildlife. He also spent three years relocating wild animals from construction sites and homes. He says the most interesting was rescuing an Echidna from a homeowner’s washing machine.
“I’ve dealt with a number of wildlife, from snakes, including 200 death adders, large goanas, green sea turtles and kangaroos, but this was my first encounter with a fur seal.
“It was important not to touch the seal, so I needed to figure out a way to get it safely back to the water where it could find it’s way back out to the harbour,” says Reece.
Helped by a colleague, the seal pup was safely herded back to the edge of the Pauatahanui Stream. Reece says after an appreciative look back, it glided into the stream and swam away towards the inlet.
The appreciative seal pup making its way back to the Pauatahanui Stream.
The seal pup swimming up the Pauatahanui Stream towards the inlet.
Desiree Craike, CPB HEB JV Traffic Manager.
Listen to regular radio interviews with our team to hear more about what they're working on for the project.
In the latest radio interview, Desiree Craike, CPB HEB JV Traffic Manager talks about traffic management and changes to road layout that motorists can expect to see over the coming month for the project.
