Dutch aim to bring back reefs via offshore wind farms

November 5, 2018

Van Oord has installed, in cooperation with the North Sea Foundation, the Natuur & Milieu organisation, and Eneco, reef balls and cages containing flat oysters within the Luchterduinen offshore wind farm, 23 kilometres west of the Dutch port city of IJmuiden.

The “Rich North Sea” project will investigate how nature conservation and sustainable energy generation can reinforce one another.

Van Oord’s installation vessel Ham 602 took the reef structures out from IJmuiden and positioned them at a depth of approximately 20 metres within Eneco’s Luchterduinen wind farm. The artificial reef includes reef balls and cages containing adult oysters. The total area for this pilot project is 3 hectares.

Until 2022, nature development within the wind farm will be scientifically investigated by Waardenburg Consultants, SAS Consultancy, and Wageningen Marine Research, including using underwater cameras. The aim is to determine whether the oysters grow and reproduce sufficiently, and whether their larvae establish themselves in the vicinity and form a reef.

Natural reefs play an important role, filtering water and acting as an attachment point and source of food, Van Oord said. Unfortunately, such reefs hardly exist any longer in the North Sea due to human intervention and diseases. During the pilot project, the participating organisations will investigate the optimum underwater conditions to enable nature to thrive within offshore wind farms.

The demonstration project will contribute to providing a blueprint for underwater nature restoration at all offshore wind farms which can then be applied when constructing new installations. The cooperating partners aim in this way to ensure that the growth of offshore wind farms goes hand in hand with nature enhancement.

Trawl fishing is prohibited within wind farms, and marine life can also attach to the support towers. This makes wind farms the ideal location for proactively reinforcing natural underwater features, according to Van Oord. The oysters will produce larvae, leading to the development of a full-scale reef that then attracts all kinds of other species, such as crabs, fish, and seals, making the wind park a veritable nursery for underwater natural features.