Impact of noise propagated through water on marine wildlife should drive wider use of gravity foundations for offshore wind farms, according to The Concrete Centre (TCC).
The TCC’s call comes following the publication of A Review of Marine Environmental Considerations Associated with Concrete Gravity Base Foundations, which has been by independently reviewed by Marine Space on behalf of the Offshore Wind Gravity Foundations Interest Group.
TCC executive director Andrew Minson said that in UK waters a significant impact associated with the installation of offshore wind farms is the level of underwater noise and sound pressure waves resulting from piling operations. He calls for wider adoption of concrete gravity base foundations to overcome the problem.
The report says that it has been shown that driving of steel piles can produce underwater sound and pressure waves at levels high enough to cause death, damage and displacement of marine mammals and some fish species; including fish eggs and larvae. As a result a number of governments in Europe have introduced legislation to reduce water-borne noise.
According to Minson, as wind farms move into deeper water these offshore environments may also provide larger potential for more extensive sound wave propagation, with less potential for attenuation than in near-shore environments.
TCC said that although concrete gravity base foundation require some ground preparation that may generate some noise, evidence from marine aggregate extraction operations demonstrates that dredging noise levels are barely detected above those associated with general vessel navigation.