Abstract
Chickerell BioAcoustics was contracted by the European Marine Energy Centre (EMEC) to carry out work to characterise the ambient noise field at the Shapinsay Sound tidal energy test site in Orkney, UK. The project was funded by the Scottish Government.
The scope of the project was to assess the methodology and equipment specified for measuring acoustic noise at EMEC’s main grid-connected tidal test site and advise on its suitability for use at the nursery tidal test site, and to train EMEC staff in the use of the recommended methodology and equipment for collecting acoustic data at the site. The project called for three surveys to be carried out using the selected methodology and equipment. Data collected from the surveys were analysed and used to characterise the ambient acoustic baseline for the site. The results of these analyses will be made available to developers testing tidal energy converter devices at the Shapinsay Sound test site, to assist with the acoustic characterisation of their devices. The characterisation of noise from specific devices operating at the test site was out-with the scope of this project.
The work involved carrying out a number of surveys through autumn and winter 2011-2012 with each survey covering a range of tidal and weather conditions. Initial surveys were carried out using the existing EMEC ‘Drifting Ears’ hydrophone equipment but later surveys used an upgraded system, the Drifting Acoustic Recorder and Tracker system developed by Chickerell BioAcoustics and EMEC.
The results of analysing the data collected show that ambient noise levels were in line with that which could be expected for this type of shallow water site, with anthropogenic noise (from shipping and a ‘seal scarer’) being the major contributors to the ambient noise field. Other significant contributions to the noise field include noise from aircraft, chains, rain, wind, and waves. No sources of noise associated with strong tidal flow across bathymetric features were identified, and no geographical variation in noise level was observed.