Spanjaards Duin

’s-Gravenzande, South Holland, the Netherlands

Building a new dune area along the North Sea through beach nourishment. On the Delfland coastline along the North Sea near Rotterdam, three types of coastal dune habitats are common: white dunes, gray dunes, and dune slacks. However, the extension of the Port of Rotterdam (Maasvlakte 2) threatens these valuable dune habitats. Therefore, the Port of Rotterdam, the Dutch Ministry of Infrastructure and Water Management agency Rijkswaterstaat, and the nature management organization Zuid-Hollands Landschap worked together to construct and develop Spanjaards Duin, starting in 2008–2009. The project was to compensate for the anticipated increase of maritime and land-based traffic emissions and the resulting increase in atmospheric nitrogen deposition that would damage natural dune vegetation. Following the initial 6.0 million cubic meters of beach and dune nourishment, natural processes such as wind action, rainfall, groundwater dynamics, and vegetative development shaped the area further into new natural dune habitats. Careful management, monitoring, evaluation, and adjustments ensure that the calcareous, nutrient-poor dune marsh and dry dune grassland are developing successfully. The improved abiotic conditions allow for the settlement of dune slack pioneer species. The compensation habitats should be completely established by 2033 when Maasvlakte 2 is expected to be fully operational.

Article cover: Shorebirds gather in the newly created dune valley. (Photo by Bert van der Valk)

Producing Efficiencies

Spanjaards Duin is the first example in the Netherlands of constructing artificial dunes to create natural dune habitats as a compensation measure. The experience and data gained from the Spanjaards Duin project have already benefited other artificial dune construction projects in the Netherlands, such as the Sand Motor project and the Hondsbossche Dunes. By using Spanjaards Duin to test the scientific models as a case study of their applicability, the project team applied a practice-as-research approach—essentially, learning by doing.

Marram grass (Ammophila arenaria) planted on the foredune naturally limits sand transport into the dune valleys. Early in the project, too much sand was blowing into the valleys, creating an environment too harsh for target species.

(Photo by Bert van der Valk)

Using Natural Processes

From the start, the project team knew they wanted to allow natural processes to shape the dunes. Crucial to this was ensuring proper grain size for aeolian dynamics and maintaining the groundwater level to support vegetation. In 2019, monitoring led the team to intervene. Excavating five gently sloping depressions in the dune valley brought the surface closer to the groundwater level. The new soil conditions now allow dune slack pioneer species, such as sand sedge (Carex arenaria), knotted pearlwort (Sagina nodosa), and goldmoss stonecrop (Sedum acre), to establish and start the vegetation succession towards a calcium-rich dune marsh.

Two dune rows are well established in 2019, 10 years after construction.

(Photo by Marieke Eleveld)

Broadening Benefits

While the project team’s aim was to provide local environmental benefits, the creation of Spanjaards Duin also provides social and economic benefits. By reclaiming part of the North Sea from historical erosion, the new dune and beach have created opportunities for nature-based recreation in this part of the Netherlands. The increased tourism will benefit the local economy and Spanjaards Duin compensation measures allow the expansion of the Rotterdam port to proceed. This further increases economic activity and growth in the region. Finally, the project provides a worldwide example of mitigating ecosystem damage on a large scale to compensate for engineering works.

A monitoring station was installed for sand and salt spray.

(Photo by Stéphanie IJff)

Promoting Collaboration

Cooperation between business (Port of Rotterdam), national government (Rijkswaterstaat), regional government (Province Zuid-Holland), nature organizations (Zuid-Hollands Landschap), consultancy firms (RoyalHaskoningDHV), and knowledge institutes (Deltares) allowed for a successful integrative approach. All these actors discussed monitoring results, alternative interventions, and the details of the design. This resulted in a collaborative and shared decision, even under high pressure. The project team also made all of the modeling data freely available online, allowing easy monitoring by all stakeholders and promoting a wider understanding.

The project team meeting with experts in the field.

(Photo by Photo by Frank van der Meulen)

Beachgoers enjoy sunny days on the beach of Spanjaards Duin.

(Photo by Marieke Eleveld)