Coastbusters – Developing systems that work with nature

The impact of climate change along the coastal regions, with higher sea levels and more extreme weather events, is on the rise. The Coastbusters project brings a new look at traditional coastal defense methods and develops the systems that work with nature.

The pioneering program discovers new concepts, including using biogenic reefs for ecosystem-based flood defence. The purpose of the reefs is to induce natural accretion of sand, attenuate storm waves and reinforce the foreshore against coastal erosion, thus adding to coastal protection.

These more ecologically sound solutions incorporate nature-inspired designs into coastal protection systems.

As the initial three-year project concluded last year, the Coastbusters consortium members (DEME, ILVO, eCoast, Sioen and Jan De Nul) presented the final project report, offering a perspective about future coastal management – backed up by several different studies in the field.

Sustainable and innovative approaches for a resilient coastal protection are crucial to safeguard environmental, economic and societal assets of the coast.

In the past, sustainable coastal management approaches have emerged within the nature-based solutions (NBS) philosophy. In this context, the application of ecosystem engineering species for achieving civil engineering objectives is not new.

From a coastal protection point of view, these species need to have the ability to modify the local physical environment by their structures or activities to trap sediments and attenuate waves.

An ecosystem-based coastal flood protection can only be brought into largescale practice as a regional solution, on condition that:

• sufficient space is present to accommodate the creation and development of (additional) ecosystems;

• key engineering species and its habitat naturally occur;

• local stakeholders support development of ecosystem services.

Once these conditions are met, solutions can be designed to translate the desired ecosystem engineering functionality into coastal management measures. 

Ghent University has receives a VLAIO Baekeland grant with support and cooperation from Jan De Nul Group, DEME Group, and the Portuguese marine institute CCMAR for its doctoral study ‘PLANT ME’.

This research into the sustainable protection of vulnerable coastal areas aims at using seagrasses. The presence of seagrass is decreasing worldwide due to poor water quality, plant diseases, climate change and coastal erosion.

With the innovation project ‘PLANT ME’, the research team plans to enable the restoration of this ecosystem by developing a new planting technique for seagrass.

The research partners – Ghent University, Jan De Nul Group, DEME Group and CCMAR – combine their expertise as researchers and hydraulic engineers to boost the planet’s biodiversity.

Also, the partners work together in the above mentioned Coastbusters project, and this is where the ‘PLANT ME’ concept came into being, with its specific focus on protecting coastal strips by planting seagrass beds.

With ‘PLANT ME’, the research partners want to enable the restoration of this precious coastal ecosystem by developing a new planting technique for seagrass.

The advantage of this method is that it is cheap to produce and that the used materials are biodegradable. With this new technique, new seagrass beds can be easily and quickly planted in shallow coastal ecosystems.

Also, ‘PLANT ME’ fits within a new research trend focusing on innovative solutions to protect coasts in a sustainable and efficient way.

In the past, breakwaters and dikes were built, but in many cases they disrupted the natural supply of sand. Today, scientists are working on solutions that also involve nature, hence the term ‘nature-based solutions’.

Elements provided by nature are used in an innovative, sustainable and resilient way to protect the same natural habitat. This does not only protect people, but also promotes services provided by nature such as biodiversity on the land-water boundary.

The trademarked Coastbusters brand represents a broader philosophy of nature-based solutions (NBS) projects.

As such, the first projects should be regarded as part of a chain of various research and innovation projects, tackling different aspects of the broader technical, ecological and social engineering topics at hand.

The benefits of NBS have been found to outweigh the costs of implementation and maintenance in a range of conventional grey coastal risk reduction measures.

Multiple examples corroborate the evidence that NBS can be more cost-effective than conventional engineered alternatives, at least when it comes to less extreme hazard scenarios. In other words, the absolute level of protection provided by the NBS strategy depends on many factors.

For example, efficacy can vary with intensity and frequency of storm events and the resilience of the ecosystem engineer to withstand impacts will depend on intrinsic biological cycles.

Hence, attention must be paid when comparing NBS to conventional solutions. Focus on one service solely will underestimate the NBS potential to deliver a wide range of benefits at both local and global scale, especially over the long term.

The results of the Coastbusters project are:

• The ambient circumstances in the Belgian North Sea are too aggressive for the smooth development of a seaweed biogenic reef. Seagrass growth, however, is possible and the first steps towards biodegradable textiles under marine conditions were taken;

• The results for cultivation of the sand mason worm are positive and this worm is a potential resilient coastal builder. However, more research is needed before dedicated “ecological engineering” can be induced;

• The pilot field tests with the blue mussel proved very promising. Although the feasibility of the basic concept is clearly demonstrated, several questions and operational challenges still remain.