A study of underwater noise generated during civil engineering works at Fraserburgh Harbour

Abstract

In the course of engineering work at the entrance channel to Fraserburgh Harbour, measurements were made of the sound pressure levels generated during various phases of the operation. Blasting with high explosives, drilling, dredging and disposal events were all monitored using a calibrated hydrophone. There was significant noise produced during each activity and the very high levels produced by blasting caused some measurement problems. These events were infrequent however, and of a very short duration compared with the other sources. The results were analysed and used to calculate stand-off or safe distances based on two different criteria. Blasting was found to be potentially harmful to marine mammals and other sea creatures within a range of 1609 m and the combined effects of drilling and dredging noise, over a daily cycle, could temporarily affect the hearing of animals remaining within a range of 281 m. Noise associated with disposal at sea produced no harmful effects.