Te Ara Tupua Horo Rangi: Protecting Infrastructure, Restoring Nature
Te Ara Tupua Horo Rangi is a landmark transport resilience project on the edge of Te Whanganui-a-Tara (Wellington Harbour), delivered by NZ Transport Agency Waka Kotahi (NZTA) in partnership with mana whenua—Taranaki Whānui ki te Ūpoko o te Ika and Ngāti Toa Rangatira—and Alliance partners Tonkin + Taylor, Downer and HEB. The project will provide a new walking and cycling connection between Ngā Ūranga and Pito-one while protecting State Highway 2 and the adjacent rail corridor from coastal storms, sea-level rise and seismic risk.
What distinguishes Te Ara Tupua Horo Rangi is its commitment to environmental regeneration alongside infrastructure resilience. Rather than simply mitigating environmental impacts, the project was designed to improve harbour ecology while delivering critical transport infrastructure.
Environmental outcomes and mātauranga Māori were embedded in decision-making from the outset through the Te Ara Tupua Mana Whenua Steering Group, ensuring cultural, ecological and engineering objectives were achieved together.
A key innovation was the adoption of the XBlocPlus® single-layer armour system—the first use of the technology in Australasia. Replacing much of the conventional two-layer rock revetment reduced rock requirements by approximately 50,000m³, cutting quarry extraction, transport demand and embodied carbon. The solution shortened the construction programme by around 12 months and delivered an estimated 10% reduction in embodied carbon compared with a traditional rock-only design, while still meeting requirements for a 100-year storm event, 50 years of sea-level rise and significant seismic loading.
Working closely with mana whenua, the project also incorporated eco-enhanced armour units known as Te Ripowai (“rippling water”), featuring textured surfaces designed by iwi artist Len Hetet. Artificial tide pools were integrated into the revetment to support marine colonisation and biodiversity. Early monitoring has already shown higher biodiversity outcomes than adjacent control habitats.
To compensate for unavoidable habitat loss, the Alliance constructed a five-hectare offshore reef enhancement consisting of 56 concrete pyramids, each five metres high and weighing 23 tonnes. The reef is the largest concrete subtidal reef created exclusively for biodiversity compensation in Australasia and compensates for 5.17 hectares of permanent marine habitat loss. Within seven months of deployment, monitoring recorded native kelps, sea lettuce, tube worms and triplefin fish establishing on the structures—an encouraging sign that ecological restoration is underway.
The project has also established a lasting legacy through its co-monitoring framework, which combines scientific ecological surveys with cultural assessments by mana whenua. This embeds kaitiakitanga (guardianship) into long-term asset management and ensures environmental outcomes continue to be measured and enhanced beyond construction.
Te Ara Tupua Horo Rangi demonstrates that infrastructure can be both resilient and regenerative. By reducing material consumption, lowering carbon emissions, enhancing biodiversity and strengthening Indigenous partnership, the project provides a model for future coastal infrastructure. It contributes directly to UN Sustainable Development Goals 11 (Sustainable Cities and Communities), 12 (Responsible Consumption and Production), 13 (Climate Action) and 14 (Life Below Water), leaving a legacy that protects communities while restoring the natural environment.