Type of infrastructure:
Location:
Country:
Netherlands
Targeted species or habitat:
Implementation period:
2021-ongoing
Implemented by:
Vattenfall, the Rich North Sea, the Royal Netherlands Institute for Sea Research, Wageningen Marine Research, and Waardenburg Ecology
TRL:
9
Funding:
Vattenfall, BASF, and Allianz

Knowledge sharing

Knowledge sharing activities include: 1) Conference presentations; 2) Coverage in Vattenfall’s monthly newsletter; 3) Social media outreach; 4) Educational initiative at SEALIFE exhibition in the Netherlands; 5) General knowledge sharing through the Rich North Sea online toolbox

Database Project

Water replenishment holes in turbine foundations

Objectives

To investigate how water replenishment holes in turbine foundations can be used by fish and other marine species to settle, shelter and be used as a feeding grounds.


Short description

Since 2021, water replenishment holes were installed in all 140 turbine foundations of the Hollandse Kust ZuidHollandse Kust Zuid is located 18 to 34 km off the Dutch coast. It comprises of 140 turbines and a total combined installed capacity of 1,500 MW. offshore wind farm in the Netherlands. The foundations, which are hollow cylinders of 8 meters diameter, feature elliptical holes of approximately 30 cm in width and 1 m in height. The holes are positioned above the seabed and just below the water surface, allowing water to flow through and providing access for various marine species to enter these cavities. The foundations are expected to provide shelter and feeding grounds for diverse marine species, including fish, crabs and, shrimp, thereby contributing to the enhancement of biodiversity in the area.

Ecological monitoring has been conducted over the past few years. Vattenfall and The Rich North Sea, in collaboration with the Royal Netherlands Institute for Sea Research (NIOZ) and Wageningen Marine Research (WMR) are investigating whether the living conditions, such as oxygen, temperature, and turbidity, are suitable for the development of marine life both inside and outside of the foundations. Through innovative monitoring techniques, such as eDNA sampling of seawater and the deployment of stationary video systems, researchers can determine the species present in the area. Preliminary results already detected organisms inside the monopile. Furthermore, abiotic and biotic parameters measured fell within the same ranges both inside and outside the foundations. Additional monitoring is planned in the coming years.