Installing large structures in shallow marine environments requires the insertion into the seabed of support elements, called piles, made of wood, steel, or reinforced concrete. These piles, once installed, extend from above the water surface to as much as several hundred feet below the seabed. Installing the piles may require impact pile driving, which uses a hydraulic hammer to repeatedly strike the top of the pile, pushing it into the seafloor. The blows are delivered approximately once per second. Depending on the size of the hammer, bottom properties, and the required penetration depth, it may take several hours and as many as 5,000 strikes to drive one pile into the seabed.
Impact pile driving produces intense, broadband impulsive sound that can propagate many kilometers. Near source (within 10 m of the pile driving activities) sound pressure levels (SPLs) range up to 220 dB peak, but vary substantially according to the size of the hammer, power of the hammer, pile material, diameter of the pile, as well as properties of the seafloor.
Two criteria for assessing the potential impacts of pile driving sounds are: 1) SPL peak and 2) cumulative sound exposure level (SELcum). For more information, please see the Advanced topic on Sound Pressure Levels and Sound Exposure Levels.
To investigate the potential effects of pile driving on fishes, several species of freshwater fish were exposed in a chamber to simulated pile driving sounds. The scientists reported that injuries varied according to the peak pressure, number of strikes, the species of fish, and whether a fish had a swim bladder. The scientists found that at the lowest sound pressure levels and fewest number of pile strikes there were no detectable injuries. Injuries reported included damage to hair cells, swim bladder, and soft tissues, according to the exposure level.
These studies were conducted in a laboratory setting and research is still needed on free-swimming animals to determine the potential for injuries on fishes in the wild from pile driving sounds. It is not known how the sounds of a pile driving operation will affect fish behavior or mask hearing of biologically relevant sounds.
Most research on potential effects of pile driving on marine mammals has been conducted in European waters in association with the development of offshore wind farms. Potential effects have been investigated on several cetacean and pinniped species.
Research results have shown that pile driving sounds may cause temporary threshold shift (TTS) or permanent threshold shift (PTS). Scientists measured pile driving sounds during construction of a wind farm off the northeast coast of Scotland. Although the levels to cause PTS have not been directly measured, based on the regulatory criteria currently in use, broadband peak-to-peak sound levels consistent with TTS onset would have been exceeded for cetaceans within 10 m of the pile driving operations and within 40 m for pinnipeds. The level estimated to cause PTS onset would occur within 5 m for cetaceans and 20 m for pinnipeds. Scientists determined that no form of injury or hearing impairment would occur at ranges greater than 100 m.
Observed behavioral responses in response to pile driving include changes in direction, swimming speed, dive profiles, group movements, vocalizations, and respiration rates. There are concerns that avoidance responses to pile driving can impact foraging, nursing, and/or mating activities, and therefore overall fitness, of a marine mammal.
Various mitigation measures, such as bubble curtains, screens, or cofferdams (an insulating sleeve around the pile), have been developed to diminish the potential impacts of pile driving on marine life. Acoustic deterrent devices have also been deployed prior to pile driving activities at many European wind farm sites in order to deter marine mammals from entering the construction zone. Pile driving activities may also begin with a “ramp-up” or “soft start” where lower hammer energy levels are used to start the pile driving process, and then the force of pile driving is gradually increased.
- Behavioral Changes
- Behavioral Changes
- Bubble Curtain
- How is sound used to protect marine mammals?
- Moderate or eliminate the effects of human activities
- Sound Pressure Levels and Sound Exposure Levels
- Wind Turbines
- Southall, Brandon L., Ann E. Bowles, William T. Ellison, James J. Finneran, Roger L. Gentry, Charles R. Greene Jr., David Kastak, Darlene R. Ketten, James H. Miller, Paul E. Nachtigall, W. John Richardson, Jeanette A. Thomas, and Peter L. Tyack. 2007, "Marine Mammal Noise Exposure Criteria: Initial Scientific Recommendations." Aquatic Mammals. 33: 411-509.
- Bailey, H., K.L. Brookes, and P.M. Thompson. 2014, "Assessing environmental impacts of offshore wind farms: lessons learned and recommendations for the future." Aquatic Biosystems. 10 (8). DOI: 10.1186/2046-9063-10-8.
- Bailey, Helen, Bridget Senior, Dave Simmons, Jan Rusin, Gordon Picken, and Paul M. Thompson. 2010, "Assessing underwater noise levels during pile-driving at an offshore windfarm and its potential effects on marine mammals." Marine Pollution Bulletin. 60: 888-897.
- Brandt, Miriam J., Ansgar Diederichs, Klaus Betke, and Georg Nehls. 2011, "Responses of harbor porpoises to pile driving at the Horns Rev II offshore wind farm in the Danish North Sea." Marine Ecology Progress Series. 421: 205-216.
- Casper, B. M. Halvorsen, M. B., Mathews, F., Carlson, T. J., and Popper, A. N. 2013, "Recovery of barotrauma injuries resulting from exposure to pile driving sounds in two sizes of hybrid striped bass." PLoS ONE. 8(9): e73844. doi:10.1371/journal.pone.0073844. (Link)
- Casper, B. M., Smith, M. E., Halvorsen, M. B., Sun, H., Carlson, T. J., and Popper, A. N. 2013, "Effects of exposure to pile driving sounds on fish inner ear tissues." Comparative Biochemistry and Physiology A. 166:352-360.
- Dolman S. and M. Simmonds. 2010, "Towards best environmental practice for cetacean conservation in developing Scotland’s marine renewable energy." Marine Policy. 34: 1021-1027.
- Haelters, J., V. Duliere, L. Vigin, and S. Degraer. 2014, "Towards a numerical model to simulate the observed displacement of harbour porpoises Phocoena phocoena due to pile driving in Belgian waters." Hydrobiologia. 756: 105-116.
- Halvorsen, M. B., Casper, B. C., Matthews, F., Carlson, T. J., and Popper, A. N. 2012, "Effects of exposure to pile driving sounds on the lake sturgeon, Nile tilapia, and hogchoker." Proceedings of the Royal Society B. 279, 4705-4714 doi: 10.1098/rspb.2012.154.
- Halvorsen, M. B., Casper, B. M, Woodley, C. M., Carlson, T. J., and Popper, A. N. 2012, "Threshold for onset of injury in Chinook salmon from exposure to impulsive pile driving sounds." PLoS ONE, 7(6) e38968. doi:10.1371/journal.pone.0038968. (Link)
- Hastie, Gordon D., Deborah J.F. Russell, Bernie McConnell, Simon Moss, Dave Thompson, and Vincent M. Janik. 2015, "Sound exposure in harbor seals during the installation of an offshore wind farm: predictions of auditory damage." Journal of Applied Ecology. 52: 631-640.
- Kastelein, R.A., D. van Heerden, R. Gransier, and L. Hoek. 2013, "Behavioral responses of a harbor porpoise (Phoceona phocoena) to playbacks for broadband pile driving sounds." Marine Environmental Research. 92: 206-214.
- Kastelein, R.A., J. Schop, R. Gransier, and L. Hoek. 2014, "Frequency of greatest temporary hearing threshold shift in harbor porpoises (Phocoena phocoena) depends on noise level." Journal of the Acoustical Society of America. 136(3): 1410-1418.
- Kastelein, R.A., R. Gransier, M.A. Marijt, and L. Hoek 2015, "Hearing frequency thresholds of harbor porpoises (Phoceona phocoena) temporarily affected by played back offshore pile driving sounds." Journal of the Acoustical Society of America. 137(2): 556-564.
- P. T. Madsen, M. Wahlberg, J. Tougaard, K. Lucke, and P. Tyack. 2006, "Wind turbine underwater noise and marine mammals: implications of current knowledge and data needs." Marine Ecology Progress Series. 309: 279–295.
- Reyff, J. 2012, "Underwater Sounds From Unattenuated and Attenuated Marine Pile Driving." The Effects of Noise on Aquatic Life. Advances in Experimental Medicine and Biology Volume 730, 2012, pp 439-444.
- Smith , M.E., Coffin, A.B., Miller, D.L. and Popper, A.N. 2006, "Anatomical and functional recovery of the goldfish (Carassius auratus) ear following noise exposure." The Journal of Experimental Biology. 209, 4193-4202.
- Teilmann, Jonas and Jacob Carstensen. 2012, "Negative long term effects on harbor porpoises from a large scale offshore wind farm in the Baltic- evidence of slow recovery." Environmental Research Letters. 7: 1-10.
- Thompson, Paul, M., David Lusseau, Tim Barton, Dave Simmons, Jan Rusin, and Helen Bailey. 2010, "Assessing the responses of coastal cetaceans to the construction of offshore wind turbines." Marine Pollution Bulletin. 60: 1200-1208.
- Tourgaard, J., J. Carstensen, J. Teilmann, H. Skov, and P. Rasmussen. 2009, "Pile driving zone of responsiveness extends beyond 20km for harbor porpoises (Phocoeana phocoeana (L.))" Journal of the Acoustical Society of America. 126(1): 11-14.
- Halvorsen, M.B., Casper, B.M., Woodley, C.M., Carlson, T.J., and Popper, A.N. 2011, "Predicting and mitigating hydroacoustic impacts on fish from pile installations." NCHRP Research Results Digest 363, Project 25-28, National Cooperative Highway Research Program, Transportation Research Board, National Academy of Sciences, Washington, D.C. (Link)
- Dahl, P. H., Christ A. F. de Jong, and A.N. Popper. 2015, "The Underwater Sound Field from Impact Pile Driving and Its Potential Effects on Marine Life." Acoustics Today. 11 (2): 18-25. (Link)
- C.A.F. de Jong and Michael Ainslie. 2008, "Underwater radiated noise due to the piling for the Q7 Offshore Wind Park." Acoustics '08 Paris.