Watercare chief executive Jon Lamonte. Photo / Supplied
Watercare chief executive Jon Lamonte. Photo / Supplied
The 14.7km route of the Central Interceptor tunnel from Mangere Wastewater Treatment Plant to Grey Lynn and connecting with the existing network. The work sites are noted along the way.
Aucklanders, it seems, love digging tunnels and have gained plenty of expertise at it.
There's the Waterview, City Rail Link, and prospects of one underwater for the second harbour crossing, and another running from downtown to Mt Roskill for the light rail system. There are even the Albert Park tunnels built as air-raid shelters during the Second World War that never did quite re-open for tourists.
Now, the 14.7 kilometre Central Interceptor wastewater tunnel — the longest, biggest and most expensive pipeline in the country — is creeping its way 55 to 75 metres underground from the Māngere treatment plant to Grey Lynn's Tawariki St, in behind Herne Bay and Ponsonby.
After two years of preparation, tunnelling began in July last year and in mid-April reached the 1km mark of its long journey. Soon the tunnelling will go under the Manukau Harbour.
The $1.2 billion Central Interceptor, being built by Watercare Services and joint venture partners Ghella (Italy) and Abergeldie (Australia), will reduce overflows into central Auckland waterways, streams and beaches, and stop the wastewater from being mixed with stormwater. The project will also upgrade an antiquated wastewater network and cater for growth over the next 100 years.
The tunnel, an immense 4.5m in diameter, is designed to hold a capacity of 226,000 cubic metres — equivalent to 90 Olympic swimming pools — and control the flow rate into the Mangere Wastewater Treatment Plant.
The Central Interceptor will now be completed in 2026 rather than 2025 because of the interruptions caused by the Covid-19 restrictions and challenges.
"The load of impacts caused by Covid is now coming to an end, and we are making great progress on the ground," said Watercare chief executive Dr Jon Lamonte. "But there will be a delay."
The joint venture contractors had to stop work during the last Auckland lockdown, and then under Level 3 struggled with productivity when 53 of the 70 tunnellers caught Omicron in February.
"We didn't have enough people to continue tunnelling safely and had to stop work for a week and a half and rebuild from two shifts a day. Ideally, we operate three shifts 24/6," said Lamonte.
The joint venture — at its peak it operates with a workforce of 500 — was also flying staff in from overseas and that came to a halt during the lockdown. Then there was the difficulty of obtaining space on the ships for materials — though most of the steel is sourced in New Zealand.
During this time the cost of shipping doubled and the price of steel went up by as much as 75 per cent — the situation was so volatile that the joint venture would place an order for steel at one price and then three days later the price would go up.
Lamonte said "we are also operating in a very tight labour market delivering big infrastructure and it's tough to find the right level of skills. As some workers go off to other jobs, we have had to pay 20-25 per cent more for the next person in. The challenges have been quite substantial."
The Central Interceptor project, part of Watercare's $18.5 billion development programme over the next 20 years, is funded by water charges. Lamonte said any blow-out in the project costs would be accommodated in the overall budget, and other projects down the track may be impacted.
Auckland has a network of sewer pipes running mainly east to west that is struggling to cope with the present load. The wastewater takes a circuitous path in the current system, and the Central Interceptor cuts straight through that. It will collect wastewater from the existing network and take it efficiently to the Māngere treatment plant.
The project also includes two smaller sewer tunnels that link the Western Interceptor with the Central Interceptor — from May Rd to Haycock Ave and on to Miranda Reserve in Avondale; and from the War Memorial Reserve to Rawalpindi Reserve in Mt Albert, a combined distance of 4.3km.
The work is being completed by two state-of-the-art tunnel boring machines, which are traditionally given female names in honour of the patron saint of miners and tunnellers, Saint Barbara.
Hiwa-i-te-Rangi, 190m long and 4.5m in height and width, is boring the main Central Interceptor tunnel, and the smaller Domenica is tunnelling the two link sewers up to a diameter of 2.4m.
To bore the tunnel, Hiwa-i-te-Rangi has a cutter head 5.4m in diameter to grind through the different soil and rock formations. The spoil is transported back to the shaft in skips, lifted out of the tunnel and trucked to Puketutu Island in Mangere to help restore the original volcanic cone.
The machine gnaws nine to 12 metres a day, and up to 5000 cubic metres of spoil, a week is taken away — enough to fill more than 150 six metre-long shipping containers. There are 17 work sites along the way, where shafts up to 80m deep are excavated to connect with existing underground pipes.
As the machine digs the tunnel, Hiwa-i-te-Rangi will lay 9000 precast concrete segment rings, each made up of six interlocking pieces and resulting in a 4.5m diameter wastewater pipe with a durable lining that protects the concrete from corrosion over its 100-year lifetime. Domenica builds her tunnels with fully-constructed pipes using a system called pipe-jacking. This involves lowering each pipe into the shaft behind the previous one, and a hydraulic jacking rig pushes it forward and gives the machine her cutting momentum.
The 14.7km route of the Central Interceptor tunnel from Mangere Wastewater Treatment Plant to Grey Lynn and connecting with the existing network. Photo / Supplied
Lamonte and his joint venture team have taken on a big load. "Water and wastewater infrastructure need constant attention," he said. "The management plan that was launched mid last year doubled in size to reflect climate change as well as growth.
"We are using low carbon, lower energy techniques. That's the nature of what we are involved with as we deliver the biggest wastewater programme ever done (in New Zealand)."
Lamonte, a former Royal Air Force Station Commander who served in the Falklands, Yugoslavia and Iraq, has plenty of experience directing large infrastructure projects. He arrived at Watercare in April last year after nearly two and a half years as chief executive of Sydney Metro.
There he oversaw a $50b development programme, the largest public transport budget in Australia, and brought the North West Metro into service.
Before that, Lamonte was chief executive for Greater Manchester Transport delivering a $4.8b programme integrating all forms of public transport and increasing Metrolink patronage.
As chief executive for Tube Lines, he was responsible for maintaining and upgrading the London Underground Jubilee, Northern and Piccadilly Lines and delivered the award-winning Green Park station.
A Companion of the Chartered Management Institute in the UK, Lamonte also managed an annual budget of $32b as director-general of finance for the Defence Equipment and Support, part of the British Ministry of Defence.
As well as dealing with the challenges of the Central Interceptor, Lamonte needs to navigate the gyrations of water reform in New Zealand. With his previous change management experience, he's not fazed.
He said the Three Waters Reform reflects the massive need for infrastructure investment across New Zealand. "Our $18.5b development programme is representative of what is happening in the country.
"Three Waters is an opportunity to get efficiencies in the water and wastewater systems by having larger organisations. If we are able to leverage the balance sheet (through the four regional entities), then we can deliver outcomes faster and sooner."
Watercare would be part of Entity A which covers Auckland, Northland and the Far North. Lamonte said Auckland Council has its Healthy Waters programme and the three northern councils have their water elements.
"We do talk to each other and work together," he said. "The Three Waters Reform is not a revolution; it's an evolution, really."
Health and safety foremost in Covid world
During the past two years of uncertainties and challenges through the Covid pandemic, Watercare's health, safety and wellbeing programme has played a leading hand.
Watercare chief executive Jon Lamonte says one thing learned over the past two years is the importance of looking after each other — at work as well as at home.
"While we can't change the uncertainty caused by the pandemic or global events, we can create certainty and reassurance in the workplace by building a deep trust between senior leaders and employees through transparent communication."
Watercare established a Covid-19 response team that regularly updated what the organisation was doing to keep staff safe and what staff can do to help protect themselves.
During February 53 of the 70 tunnellers working underground in a confined space on the Central Interceptor project caught Omicron. Work was stopped until there were enough skilled workers to carry on.
On infrastructure sites around Auckland, Watercare is operating a health and safety programme with contractors called "Back to Basics." Frontline workers were asked to come up with one action each week that will make their site safer. They are empowered to take collective health, safety, and wellbeing into their own hands.
Following one initiative Watercare is now using remote-operated vehicles instead of divers to inspect and clean water reservoirs.
Lamonte says truly safe workplaces protect a staff member's mental health as well as their physical health. While trust, open communication and strong work relationships improve an employee's mindset at work, their mental wellbeing needs to be actively checked.
The MATES in Construction programme has moved on this approach. The programme uses specially-trained field officers to build positive working environments on construction sites, identifying at-risk team members and getting them the help they need.
Central Interceptor team members are founding members of this initiative.
• Watercare is a sponsor of the Herald's Project Auckland report.
