Port of Vigo tests an environmentally-friendly alternative to concrete for its facilities

by Thomas Jensen
Underwater visor

Converting infrastructure from grey to green

This article was featured in Eurofish Magazine 3 2023.

The Port of Vigo in collaboration with ECOncrete, a leading company in the field of eco-friendly marine infrastructure, DTU, the technical university in Denmark, and Cardama Shipyards is installing biomimetic structures made with a concrete that is more environmentally friendly than conventional concrete. Marine organisms that naturally attach to the structures over time are being quantified. The results will show whether the organisms that colonise the structures are more biodiverse and more numerous than those that colonise conventional concrete.

The European Blue Growth strategy aims to support sustainable growth in the marine and maritime sector by exploiting the potential of the seas and oceans to contribute to the European economy. The blue economy comprises all the economic activities related to the oceans, seas, and coasts, including activities in both established and emerging sectors. Coastal and environmental protection are among the economic activities included in the emerging sector. Activities are termed emerging because of the low level of information and the lack or inadequacy of statistical data, ­standardised indicators, and other tools useful to measure their economic impact.

Artificial reefs can have multiple functions

One of the methods of coastal protection is by building artificial reefs, which, by decreasing the force and velocity of waves, protect coastlines from the effects of storms and flooding. Reducing the impact of the waves also mitigates shore erosion and land retreat. However artificial reefs also serve other purposes. For example, they can create high value biodiversity hotspots by offering refuge to different fish species, and they can increase the biomass of fish and shellfish in the area of the reef. This in turn can bring socioeconomic benefits in the form of enhancing the catches of the local fishermen, or by increasing tourism and thereby employment in an area. Artificial reefs take many different shapes and sizes and a variety of material are used to build them. But the design, production, and installation of artificial reefs, must take sustainability criteria into account in terms of minimising the use of non-renewable resources, energy, the production of waste, and emissions of greenhouse gases.

Climate change and the risks it imposes is forcing cities not only to adapt their infrastructure but also to take steps to reduce their contribution to global warming. Today some 70% of coastal infrastructure is built with traditional concrete which is toxic to many marine creatures, and requires regular maintenance. In 2018, the Port of Vigo in Spain embarked on a complex three-phase programme, Peiraos do Soplor, the aim of which is to change the “grey” infrastructure in the port to “green”, that is, improve the integration of port and coastal facilities with the environment. It will develop structures that support natural processes of bio deposition and growth. The programme also has a social perspective—to improve the interaction between the port and the city. The environmental benefits of the ­programme stem from the development of new ways to reduce the impact of coastal and port infrastructure on the environment, says Carlos Botana, Head of the Sustainability Department, at Vigo Port Authority. We think it is possible for the activities carried out in the port to be compatible with the ­environment. The ­interaction with the public is important to give people an idea of the port activities and their economic and environmental impact. We need to protect and conserve the ecosystem in and around the port and to do this we need to involve the public and other stakeholders. The programme, among other activities, will see the design and installation of structures made from a special concrete as well as the construction of several meters of artificial reef using the same material.

Other ports too seek to reduce their ­environmental impact


The Port of Vigo is not the only European port investing in artificial reefs. In Rotterdam, the port authorities in partnership with other organisations have just completed construction of a trial living breakwater made of 17 concrete blocks. The wave barrier will protect the shore from large ship waves but will also restore the intertidal environment and provide shelter for fish such as sturgeon and eels as they migrate between the Atlantic and the river Meuse, thus restoring and preserving biodiversity. The artificial reef is 25 m long and 3 m high so the top layer will be visible at low tide. It is designed to allow the passage of water and sediments enabling ecological foreshores to develop that will grow with rising sea levels. The artificial reef uses recycled and innovative materials and will create a sheltered area for migratory fish, birds, and aquatic plants. Concrete is commonly used in the construction of artificial reefs, but it is by no means the only material used for this purpose. Ships, train coaches, oil rigs, tyres, even aircraft are among the structures that have been sanitised and placed in the sea to form artificial reefs. Over time they are colonised first by lower marine life forms which in turn attract higher forms to create an ecosystem.

In Vigo the first phase of the ­Peiraos do Soplor programme, PuertAlMar, was executed in collaboration with the University of Vigo and it mapped over the course of a year the development in the community of organisms that attached to structures designed to attract marine life. The structures were made of various materials, concrete, stone, etc., formed into different shapes. The researchers used biomimetics, the science of reproducing natural forms in artificial structures, to create objects that would maximise, both in terms of number and diversity, the attachment of lifeforms. These objects were installed under existing piers and the abundance, composition, diversity, pattern of succession, and functions of the new ecosystem created were monitored. The results (some 180 species on a piece 20 cm square in the course of a year) could be compared with those from the colonisation of conventional, non-biomimetic, infrastructure. The port authorities are responsible for the preservation of the environment in the entire bay or ria in which the port is located. Knowing the species that colonise these structures will influence the design of infrastructure in the future to make it more attractive for the colonising organisms. The structures will also be deployed in coastal areas in the bay that have been affected by the industrial activities in the port. The monitoring offered insights into communities of organisms that could function as carbon sinks as well as into the rebuilding of commercially valuable fish stocks. Such communities could be important for their climate change mitigation effects, while commercial fish stocks are of socioeconomic value for fishers. Improving the environment in the port will also directly benefit the artisanal fishers who are active in the bay by improving stocks of the species they target.
Combining ­engineering objectives with ­environmental goals

Based on the results from the first phase, PuertAlMar, of the Peiraos do Soplor programme, the second phase, Living Ports, involves a collaboration with three other partners to create a sea wall, coastal armour units, and five bio enhanced moorings. The programme thus combines environmental objectives, the ­restoration and conservation of ecosystems, with engineering goals, the design and construction of port infrastructure. It increases the ecosystem services the port provides by recreating natural habitats that were lost during the construction of the port infrastructure. These natural habitats will offset some of the carbon dioxide that was emitted during the construction. The programme coordinator is ECOncrete, a firm that makes ­bio-enhancing concrete solutions for coastal and marine construction projects that has the same structural performance as conventional concrete. ­Infrastructure built with the new concrete will store carbon and contribute to regenerating ecosystems. Moreover, compared to the traditional type, the new concrete offers increased compressive strength and chloride resistance improving durability and longevity. The new structures have the potential to reduce environmental mitigation costs and will require less frequent maintenance which will also save on costs. The growth of marine life on the structures is monitored by a team from DTU, a technical university in Denmark, and the idea is to establish whether there are more fish in the vicinity of structures made with the new concrete than near structures made with conventional concrete. The structural properties of the new concrete are also monitored to assess it in relation to ­conventional ­concrete. The project will also monitor noise levels in the water to see whether marine life that attaches to one side of a wall reduces the noise levels on the other side of the wall. If there is a reduction in noise levels it would be yet another benefit of these structures that could be promoted to the public.

An observatory ­integrates the public into the project

The project includes a public information and dissemination element to educate the local population about the environmental impacts of infrastructure development and to highlight the need to find sustainable solutions so that ­economic development is not at the cost of the ­environment. Called Nautilus, the underwater observatory offers visitors a view of a large area of specially designed concrete panels established to attract the marine life that populates the intertidal zone as well as underwater. The aim of the observatory is both to entertain and to educate and it is aimed both at school children and scientists. The young people also benefit from workshops and other educational activities that inform them about the port’s marine ecosystem, the services it offers, and the importance of preserving it. Since it opened on 24 March 2023 the observatory has recorded over 11,000 visitors in one month.

Cross-disciplinary teams can bring about better results

In the third stage of the Peiraos do Soplor programme all the activities from the first two stages will be scaled up. The project proposal is currently being ­written, says Mr Botana, and it envisages another underwater observatory, and different structures designed for different stakeholders. The plan is to include all the developments successfully tested in the earlier phases of the programme and to scale them up. Ultimately, the programme seeks to verify that the structures built with the new material do offer environmental benefits to the area. Since replacing existing concrete infrastructure with the new material is not feasible, the results from the programme will be used when building new facilities in the future. The programme also demonstrates how the engineering and sustainability departments at the port and the department of ecology at the University of Vigo can work together in the design and construction of infrastructure in the port and coastal areas in the bay. The infrastructure being built must take into account the potential impacts of climate change such as loss of biodiversity or the occurrence of extreme weather events. Infrastructure built of a new material with greater structural strength will be more resilient to such events and will have a proportionately lower impact on the environment than infrastructure made of traditional materials. For Mr Francisco Barreiro, environmental technician at Port of Vigo, who comes originally from the department of ecology at the university, it is critical that all the relevant knowledge, whether technical, environmental, social, or economic, is brought together when creating coastal infrastructure more integrated with the environment and to reduce the risk of undesirable impacts.

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