Underwater noise emission during the Phase I construction of the C-Power wind farm and baseline for the Belwind wind farm
Haelters, J.; Norro, A.; Jacques, Th. (2009). Underwater noise emission during the Phase I construction of the C-Power wind farm and baseline for the Belwind wind farm, in: Degraer, S. et al. Offshore wind farms in the Belgian part of the North Sea: State of the art after two years of environmental monitoring. pp. 17-37 In: Degraer, S.; Brabant, R. (2009). Offshore wind farms in the Belgian part of the North Sea: State of the art after two years of environmental monitoring. Management Unit of the North Sea Mathematical Models, Marine Ecosystem Management Unit/Royal Belgian Institute of Natural Sciences: Brussel. 287 + annexes pp., more |
| Abstract | The noise level under water was measured at the Bligh Bank before construction works started (reference level, T0) and at the Thorntonbank during construction works (T1). The reference underwater noise levels measured at the Bligh Bank were 95 to 100 dB (re 1μPa) between 10 Hz and 2 kHz, levels similar to those measured previously at the Thorntonbank site during similar weather conditions (wind force 2-3 Bft, sea state 1-2). Slight differences may be due to the noise generated by the Interconnector and/or Zeepipe pipelines near the Thorntonbank site (not detected during the Bligh Bank monitoring), to local characteristics in the underwater topography, to the ad hoc shipping traffic near the monitoring stations and to meteorological conditions. Levels during high and low tide did not show significant differences. Only limited effort could be spent at measuring underwater noise during the construction works at the Thorntonbank windfarm site. The levels measured were 5 to 25 dB higher than the background noise levels, similar to increases caused for instance by passing ships.However, no specific measurements related to the construction of offshore windfarms, such as cable laying or the laying of the scour protection could be measured. Future underwater noise measurements will be focused at such activities, and at pile driving. Also efforts will be made to finetune the technical aspects of the measurements and the analyses, and at assessing possible impacts of the noise measured. |
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