Future of inter-regional train travel in New Zealand

Plan for the interior of the redeveloped Britomart train station Source: City Rail Link Ltd (cityraillink.co.nz)

Waitematā enabling works awarded a leading rating

The City Rail Link (CRL) project aims to achieve sustainability excellence by carefully determining which resources are used, optimising the carbon footprint, avoiding waste and leaving a positive social and cultural legacy for Auckland

For the Waitematā Station (Britomart), this included creation of a new public square, Te Komititanga, designed by Mana Whenua artists and weavers, in consultation with CRL’s Mana Whenua Forum representing eight different iwi across the isthmus.

Waitematā Station is the busiest on the Auckland rail network, situated at the heart of the CBD and housed in the historic and protected Chief Post Office. This presented significant construction obstacles, including the proximity to offices and residential building, some of which also have heritage status, and required strict limits around noise and vibration.

Resource efficiency was essential to the design (which also received a leading design rating), planning and implementation of the works, leading to 97 percent of construction and demolition waste and 100 percent of spoil diverted from landfill and significant efficiency gains over CRL’s 100-year lifespan.

These include a 17.8 percent reduction in peak operational energy use, 23 percent reduction in operational carbon emissions and 58 percent reduction in water use.

Leaving a legacy for future generations was a cornerstone objective for the project, with a strong focus on knowledge sharing designed to extend beyond the life of the works and to inform the design and implementation of future projects.

This objective was achieved through a well-defined and integrated sustainability management system with regular reviews and reporting to project sponsors, leadership teams, the Mana Whenua Forum and community liaison group. This provided for sharing sustainability knowledge by both CRL Ltd and the contractor, both within the team and wider (Auckland Transport, external stakeholders and the general public).

Waste management highlights included keeping 8,303 tonnes of construction and demolition waste and 24 tonnes of office waste out of landfill. Assisting this achievement was procurement and design optimisation, onsite separation of concrete, steel, clean fill, office waste and compost and the reusing of waste material on and offsite.

A change in construction methodology from using contiguous piles in pre-treated columns to diaphragm walls and mini piles underneath the Chief Post Office greatly assisted in achieving energy efficiencies. The replacement of diesel generators with grid electricity for site offices and on-site equipment also helped.

Other highlights included water conservation, reducing construction water consumption by 21 percent and generating a forecast 58 percent reduction in water use of the lifecycle of the station. A 13 percent saving is projected for the urban realm during the 100-year design life of CRL.

The achievement follows the ‘Excellent As Built’ and ‘Leading Design’ ratings awarded earlier for CRL works at the lower end of Albert St (Contract 2)), as well as a wide range of honours for innovation, sustainability, engineering and circular economy practices bestowed upon the project.

The Waitematā works involved the construction of twin 136m-long tunnels under the Chief Post Office, a protected historic building, and lower Queen St and the reinstatement of the surrounding urban realm.

The works were conducted by the Downer/ Soletanche Bachy (DSB) joint venture, while design of the works was by Aurecon, Mott MacDonald, Grimshaw, Jasmax and Arup.

Sweeney says he wants to acknowledge the work of the contractors on the Waitematā works and the Link Alliance, which has adopted the ISC sustainability guidelines in the design and construction of the project’s two new underground stations, an above-ground station, bored, mined and cutand-cover tunnels and connections to the Western Line and all rail systems.

“CRL is what I believe is New Zealand Aotearoa’s highest value employment project, bringing big changes to the construction industry,” Sweeney says. “During the year we continued to use the scale and complexity of the project to demonstrate our ability to have a positive impact on the wider industry.”

Downer environment sustainability manager Sarah Sutherland says achieving the highest

IS-rated project in New Zealand is a great accomplishment: “This success was built on the collaborative relationship between CRL and the DSB joint venture and underpinned by the strong sustainability culture set by our senior leaders.

“It is our earnest hope that by setting the bar high, we provide the inspiration for construction projects that follow to achieve even better, more sustainable outcomes,” Sutherland says.

The project has five key environmental and social objectives: reducing resource consumption; zero waste to landfill; creating positive social outcomes; ensuring positive outcomes for Mana Whenua and that the project appropriately reflects Māori culture; and best practice governance and reporting.

The Waitematā works will result in a 17.8 percent reduction in peak operational energy use and 23 percent reduction in operational carbon emissions over the project’s 100-year lifespan. In terms of the project’s aspirational goal of zero waste to landfill, 100 percent of spoil, 97 percent of construction and demolition waste and 74 percent of office waste was diverted from landfill.

“These are meaningful and tangible results that reflect our commitment to sustainable infrastructure construction and, given CRL’s 100-year lifespan, will benefit Aucklanders for generations to come,” Sweeney says.

The Link Alliance’s construction of the tunnels and stations is already delivering significant benefits through initiatives (see box above) such as reducing the embodied carbon of the concrete used by substituting fly-ash for cement as well as energy efficient station designs that, including minimising lighting and ventilation energy use.

These initiatives are expected to result in a 16 percent reduction in embodied carbon, a 19 percent reduction in construction energy emissions and a 22 percent reduction in operational energy emissions, for total savings of 60,515tCO₂e over the 100-year designlife.

Sweeney says these facts represent an important achievement for New Zealand and the construction industry, in particular: “Construction and demolition accounts for about half of New Zealand’s total waste to landfill, so as the country’s largest infrastructure project, we have an important leadership role to play in reducing waste to landfill.

“Our peers in the industry can see what we’re doing and how we’re doing it and this is going to lead to a signficant culture shift and help lead the construction industry to a more sustainable approach to its work,” he says.

Among the re-use purposes the waste has been put to include basalt rock from Maungawhau Station (Mt Eden) being used to build sea walls on the Coromandel Peninsula and create bike obstacles at the Totara Park Mountain Bike Club in South Auckland and timber offcuts being used for works of art.

Glossary for readers less familiar with Te Ao Māori

Tangata Whenua:

The indigenous Māori people of a particular area of New Zealand or of the country as a whole.

Te Aha a Turanga:

Manawatu Gorge bypass project

Mana Whenua:

The right of a Māori tribe to manage a particular area of land

Korowai:

A traditional woven Māori cloak worn as mantle of prestige and honour. The name Korowai is symbolic of leadership, and includes the obligation to care for the people and environment.

Te Toitutanga:

Integrity

Te Ara Kotahi:

The pathway that Māori and the Crown walk together on as envisaged by Te Tiriti o Waitangi.

Te Tiriti:

The Treaty (of Waitangi) is widely accepted to be a constitutional document that establishes and guides the relationship between the Crown in New Zealand (embodied by our government) and Māori. The Treaty promised to protect Māori culture and to enable Māori to continue to live in New Zealand as Māori. Increasingly this phrase is used in shorthand to refer not only to the document, but manifestations of co-governance and other partnership type behaviours that breathe life into those obligations.

The publishers of AsiaPacific Infrastructure, Property&Build and Industrial Safety News welcomed Infrastructure Sustainability Council (The ISC) as a Content Partner in July 2022. General Manager, New Zealand Adrienne Miller, is a lawyer who, as well as her role at the ISC, has served on the Building Advisory Panel at MBIE, Infrastructure New Zealand’s WIN Advisory Board and is a trustee on the Board of Diversity Works New Zealand. She is involved in mentoring programmes and writes and speaks on issues facing the construction and infrastructure sector. Adrienne.Miller@iscouncil.org +64 27 693 9753 LinkedIn.