At HGM, we believe construction should do more than just deliver infrastructure—it should also be sustainable and enhance the natural environment. When Lyttelton Port Company (LPC) embarked on an innovative project to create ecologically engineered marine habitat along the shoreline of its reclamation area, we were immediately drawn to the project.
As an established contractor to LPC with a proven track record, HGM was awarded the contract to manufacture 228 precast ECOconcrete Coastalock armour units. Designed to be installed in clustered formations, these units dissipate wave energy while creating valuable intertidal and subtidal habitats for marine life.
Each Coastalock unit weighed 3.5 tonnes and was specifically engineered with a highly textured surface featuring numerous crevices and water-retaining pockets. This complex profile mimics natural rocky shorelines, providing ideal conditions for marine organisms to establish and thrive.
Using four specialised moulds supplied by LPC, our team manufactured each unit from ECOconcrete, incorporating a sustainable concrete admixture that enhances durability while reducing environmental impact compared with traditional concrete mixes. A specially formulated bio-mud was applied to the inside of each mould, creating the distinctive textured finish designed to encourage the early establishment of algae and other marine organisms.
Quality assurance was fundamental to the project’s success. Drawing on HGM’s extensive expertise in constructing concrete structures, we developed a detailed production methodology to ensure every unit met stringent quality standards. The process was continually refined throughout the seven-month production programme, with comprehensive production records maintained for every unit and regular quality inspections carried out to ensure consistency across the entire project.
As the first project of its kind in New Zealand, the Coastalock habitat initiative represents an exciting advancement in sustainable coastal engineering. Early monitoring following installation showed promising results, with green algae successfully colonising the units—a positive indication that the engineered habitat was performing as intended.
This project demonstrates how innovative thinking and collaborative partnerships can deliver infrastructure that not only performs its engineering function but also restores and enhances the surrounding environment. HGM is proud to have played a role in helping Lyttelton Port Company set a new benchmark for sustainable coastal infrastructure.
