A study has been conducted in cooperation between Nord Stream, the Swedish Defence Research Agency (FOI) and the Swedish Nature Protection Agency, in order to establish the underwater noise levels in the sea close to the Natura 2000 area at Norra Midsjöbanken, to the south of Gotland.
Noise emanating from regular commercial maritime traffic as well as Nord Stream’s construction works has been assessed. The study was conducted from January to April this year.
The report confirms that Nord Stream’s construction works caused an increase in the underwater noise levels which is comparable to that of passing commercial vessels. The construction works were carried out during a limited period of time and in a limited area. The ambient underwater noise could mainly be attributed to the vessels involved in the construction works, e.g. the pipe-lay vessel or the anchor handling tugs, and to a lesser extent from other construction related work such as trenching or placing the pipe on the seabed.
”We have been able to apply our unique competence within marine environment research in order to successfully conduct measurements in an area in the middle of the Baltic Sea. During the study, we have developed new methods of analysis for the purpose of measuring underwater noise levels as well as noise from commercial maritime shipping. We were surprised to learn about the high levels of underwater noise caused by passing vessels using the route close to this Natura 2000 area,” says Torbjörn Johansson, Researcher in underwater acoustics with the FOI.
Press Release, September 18, 2012