Three ways ports can harness nature to deliver even more value

Dredging works have always been a part of port management and are necessary to maintain operations. Today though, new rules and regulations place far more scrutiny around where and how dredged material is disposed.

Ports must carefully select where to dispose of dredged sediment to avoid impacting marine ecosystems. However, in cases where this disposal area is too close to the port, there’s a risk that sediment flows back into the port – leading to renewed dredging requirements and higher costs.

Rather than disposing of dredged materials, what if there was a way to reuse sediment or embed it in other ecosystems to create value and simultaneously reduce the need for future dredging?

That’s exactly where some NbS can offer a solution, as we saw during our involvement in the mud motor project with the Port of Harlingen in the Netherlands. Dredging around 1.3 million m³ of fine sediment per year from its harbour basins, the port found that a potentially large proportion of this material was flowing back into the port.

To avoid this, the port began disposing of dredged material in front of salt marshes to trap the sediment and avoid it flowing back. This simultaneously reduced the amount of dredging required and increased tidal marsh elevation, helping the marsh to grow with rising sea levels and protecting the hinterland from flooding.

This is a strong example of how NbS can benefit port operations, local ecosystems and flood safety at the same time.

One of the greatest threats to port infrastructure and operations is increasingly volatile coastal dynamics.

Dynamic, extreme waves can damage breakwaters, disrupt berthing, and lead to significant downtime during loading and unloading. While building sturdier breakwaters can offset this, doing so requires extensive investment and can involve using non-renewable materials in a way that disrupts local ecosystems and causes additional emissions.

In the same way that nature-based solutions can reduce the costs of coastal protection, they can also offer ports a more cost-effective, dynamic, and adaptable way to handle increasingly volatile waves. For example:

• Sandy foreshores can replace or reinforce rubble mound breakwaters to shelter vessels and offer storm protection
• The dense roots of mangrove belts can capture sediment and dissipate wave energy, creating coastal barriers and reducing erosion
• Salt marshes reduce incoming waves, and their vegetation can capture sediment in intertidal zones to mitigate wave impacts
• Natural or artificial oyster and coral reefs can break extreme waves before they reach the port

All these examples can dampen waves, leading to reduce downtime, better nautical safety, and more shelter from flows and storms. These solutions can also offer additional benefits to governments or local communities, such as improved marine habitats that benefit fisheries.

With some adjustments to quay walls, revetments, and other hard structures, ports can promote biodiversity and support marine ecosystems that otherwise wouldn’t settle in urban and industrialised waters.

By engineering the surface of hard structures to support marine life, ports can contribute to biological diversity while purifying water and dissipating hydrodynamic energy.

This is important in helping ports mitigate the negative impacts on ecosystems and water quality.

Examples include:

• Adding varied textures and substrate types to quay walls and revetments, increasing structural stability while creating new marine habitats
• Building hanging and floating structures that mimic natural underwater environments to create marine habitats, enhance biodiversity, and improve water quality
• Installing habitat creation units to create nursery environments for juvenile marine life and support ecological balance

While these enhancements help hard structures support biodiversity, they provide significant advantages to port authorities. By demonstrating a commitment to sustainable, environmentally conscious operations, ports can bolster their license to operate, foster better relationships with community stakeholders, and make it easier to secure future investments.