From Science to Policy: Addressing Underwater Noise in Germany

Human activities are increasing in the marine environment causing underwater noise. The most intense source of underwater noise is pile driving during construction of offshore wind farms. This might disturb marine mammals, such as the harbour porpoise. Therefore, measures to prevent and mitigate underwater noise are necessary.

In order to be effective such measures should be regulated. However, regulators have to demonstrate and assess the applicability, efficiency and effectiveness of mitigation measures. This requires scientific knowledge on the impact of underwater noise while the normative aspects of noise mitigation have to be considered.

Since 2008, operators have to comply with limits for pile driving noise during the construction of offshore wind farms in Germany. Since 2011, they have to use technical noise abatement systems. The Federal Maritime and Hydrographic Agency (BSH) approves offshore wind farms and monitors underwater noise in the German Exclusive Economic Zone (EEZ).

Since 2017, BSH operates the expert tool MarinEARS, which includes the scientific basis for regulating underwater noise. The data shows that the regulations have been successful in the recent years. Underwater noise affected less than 10 percent of the German EEZ at any time, including adjacent nature conservation areas.

Here, BSH outlines a step-wise approach to establish a regulatory framework for pile driving noise and to implement mitigation measures in practice. It highlights the successful cooperation between science, authorities and industry in recent years to minimise the impact of underwater noise on the marine environment.

These lessons learnt from addressing underwater noise from the construction of offshore wind farms, are currently being transferred to underwater noise from e.g. shipping and the operation of offshore wind farms. Furthermore, the EU issued for the first time thresholds to limit underwater noise in European waters in 2022.

BSH plays also a crucial role in the development of European threshold values and the standardised evaluation of underwater noise. This is important for making the assessment of underwater noise comparable and reproducible. In this way, common goals for the protection and sustainable use of the seas can be set in the future.