Ecologically Engineered Concrete Habitat Units Enhance Marine Biodiversity at New Zealand Port

Lyttelton Port Company (LPC) introduced ecological design principles into its coastal infrastructure through specially engineered concrete habitat units. The project shows how maritime structures can support marine biodiversity while continuing to fulfil their primary engineering function.

The company is installing around 220 ECOncrete Coastalock units along a newly reclaimed seawall. The units are arranged in clusters that create both intertidal and subtidal habitats. This configuration encourages marine life to establish itself in an area typically dominated by conventional hard infrastructure. During the first phase, LPC installed 22 units along the eastern section of the seawall. Each unit weighs approximately 3.5 tonnes.

Concrete Designed to Encourage Marine Life

Traditional seawalls often rely on quarry rock. While structurally effective, these surfaces offer limited opportunities for marine organisms. The Coastalock units address this challenge through ecological engineering principles embedded in their design.

Contractors can rotate the units during installation to create small pools that retain seawater at low tide. These pools mimic conditions found in natural rocky reef environments. The textured surfaces also provide shelter and attachment points for algae, shellfish and other marine species.

Early results suggest that the approach is working. Trial units installed in February 2026 have already shown signs of green algae growth. This development indicates that ecological colonisation has begun.

Collaboration Between Ecology and Engineering

Marine ecologist Oliver Floerl from environmental consultancy LandWaterPeople (LWP) worked with LPC to develop the concept. The project team combined ecological expertise with structural and geotechnical engineering knowledge throughout the design and installation process.

According to the project partners, the habitat units form part of a broader biodiversity strategy for the reclamation area. LPC also plans to install smaller “living seawall” habitat boulders along the southern seawall. These elements will complement the larger Coastalock units and create additional opportunities for marine species.

Material Innovation for Coastal Design

The project highlights how material innovation can contribute to nature-inclusive infrastructure. Designers and engineers increasingly evaluate materials not only for structural performance but also for their environmental value.

As ports, waterfront developments and coastal protection projects seek more sustainable solutions, ecologically engineered concrete offers a promising approach. By combining durability with habitat creation, these materials demonstrate how infrastructure can actively support biodiversity within the built environment.

Source & photo: Lyttelton Port Company