Dredging Noise

The process of dredging produces large amounts of underwater noise, mainly from sound arising from the draghead moving over the seabed but also from the noise from the submerged pipework and pump arising during loading operations when gravelly sediment is drawn at high velocity with seawater into the ship.

Noise measurements can be made as part of the environmental impact assessment to address the question of acoustic disturbance arising from dredgers loading in the areas close to local fishing grounds.

Measurement involves taking background noise measurements as well as during operation and comparing these over ranges of several kilometres whilst concentrating on environmentally sensitive areas to work out the increased levels of noise. These levels are then calculated with the threshold of hearing for the species in question to estimate whether it could have an effect.

Other parameters that are evaluated offshore, if possible, are the tidal and differing sea states due to weather and their effect on the spreading of the noise and its attenuation.

For any further information on dredging, please contact us.