1 MEASUREMENTS OF UNDERWATER PILING NOISE DUR- ING NEARSHORE WINDFARM CONSTRUCTION IN THE UK: POTENTIAL IMPACT ON MARINE MAMMALS IN COMPLI- ANCE WITH GERMAN UBA LIMIT Benjamin Ford†, Jian Jiang †*, Victoria L. G. Todd†* and Ian B. Todd* †Southampton Solent University, East Park Terrace, Southampton, SO14 0RD, UK. *Ocean Science Consulting Ltd., Spott Road, Dunbar, East Lothian, EH42 1RR, Scotland, UK. email: james.jiang@solent.ac.uk Offshore pile and conductor driving can potentially cause acoustic disturbance to marine mam- mals, such as cetaceans (whales, dolphins and porpoises), the odontocetes (toothed cetaceans) of which are particularly reliant on the underwater sound field for spatial orientation, navigation, prey capture, communication, and predator avoidance. Disturbance ranges from behavioural changes, masking of communication signals, and temporary or even permanent hearing loss. There is currently no specific legal noise threshold in UK waters, but the Marine Management Organisation (MMO) has stipulated the requirement for noise monitoring during pile-driving operations when some windfarms are constructed. Measurements presented in this paper were taken during nearshore pile driving in the UK from a support vessel located 750 m from each pile (wind-turbine foundation). Results were compared with a threshold issued by the German Federal Environment Agency (UBA). Noise levels beyond the measurement location were pre- dicted using a numerical model. Comparing results with the Southall criteria (Southall, B. L., et al., Marine Mammal Noise Exposure Criteria: Initial Scientific Recommendations, Aquatic Mammals, 33 (4), 2007), the Joint Nature Conservation Committee (JNCC) 500 m exclusion zone offered protection for most of marine mammals during pile driving events in this particular case. Keywords: Underwater piling noise, wind-farm, marine mammals, UBA limit 1. Introduction The UK generates more power from offshore wind farms than any other country in the world [1]. This number is increasing such as Rampion Offshore Wind Farm [2], Dudgeon Wind Farm [3] and Race Bank Wind Farm [4], which will increase the amount of UK individual offshore wind turbines by 274 [2-4]. A potential consequence of these developments is an increase in exposure of marine mammals to potentially damaging anthropogenic noise, especially during the construction period. Construction of an offshore wind turbine involves the process of piling, which generates high levels of impulsive noise. Noise levels generated are influenced by many factors, including pile size, hammer energy (driv- ing power), and geological properties at the site. Previous measurements show that source level can be between 210 dB and 250 dB (ref. 1 μPa) [5]. Frequency content can be from as low as 1 Hz up to 100 kHz. There are a range of effects that excess noise can cause depending on level and marine species in question. For example, Temporary Threshold Shift (TTS) is a result of excessive noise that causes an animal’s hearing threshold to increase temporarily making it harder to hear. Permanent Thres h- brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Solent Electronic Archive