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Testing CEAF (Common Environmental Assessment Framework) in SEANSE case studies - Impact of piling for wind farms on North Sea harbour porpoise population


This study, conducted within the SEANSE project, is a test of the CEAF modelling tool (Common Environmental Assessment Framework) to quantitatively assess the cumulative impacts of piling for offshore wind farm construction on the harbour porpoise population. This report describes the details of this stage in the procedure and illustrates its application to three hypothetical scenarios for North Sea offshore wind development between 2016 and 2038.

Application in MSP:
Type of Issue:
Type of practice:
Stage of MSP cycle:
Cross-border / trans-national aspect:
Coherence with other processes:
Key words:


  • How would harbour porpoises be affected by offshore wind farm development?
  • How can the impacts of noise pollution on marine mammals be assessed?
  • Are there efficient models to evaluate offshore wind farm impacts on marine mammals?
  • What improvements could be made to the CEAF modelling tool?


This study was conducted within the context of the SEANSE project, whose objective was to "develop a coherent (logical and well-organised) approach to Strategic Environmental Assessments (SEAs), with a focus on renewable energy in support of the development and effective implementation of MSPs."


The aim of this study was to assess the cumulative effects of wind farm development in the North Sea on the harbour porpoise population.


This study reports estimations of the effects of marine piling noise on marine mammal populations, specifically on harbour porpoises, for future Dutch offshore wind energy projects and for three different scenarios of offshore wind farm development in the North Sea. The cumulative effects of the wind farm development are assessed using the procedure designed and improved by Heinis et al. 2019. Calculations are based on the source sound level, local environmental factors, knowledge of sound propagation in water and harbour porpoise’s population dynamics in the studied area.


Main results concern estimated disturbances to harbour porpoise and resulting population reduction for each of the three scenarios of offshore wind development defined in the SEANSE project. Some suggestions for improvement of the CEAF model are also formulated.


The procedure applied to harbour porpoises as a case study can be considered as a step in the right direction to improve the assessment of the (cumulative) impact of impulsive noise on the populations of marine mammals.

Responsible Entity:

Netherlands Organisation for Applied Scientific Research (TNO)

Funding Source:

Co-funded by the European Maritime and Fisheries Fund.

Contact person:

Oude Waalsdorperweg 63

2597 AK Den Haag

P.O. Box 96864

2509 JG The Hague

The Netherlands

T +31 88 866 10 00

F +31 70 328 09 61