Click either choice below to hear pile driving activity before and after a bubble curtain system is activated. Please note, this sound recording demonstrates the effectiveness of this mitigation option and is not meant to demonstrate how it is actually done (e.g., the bubble curtain would already be up and operational before any piling started in a real-world scenario):
Sound credit JASCO Applied Sciences, www.jasco.com; released under Creative Commons Attribution, Non-Commercial.
DescriptionBubble curtains can be deployed to reduce or mitigate impacts from high noise levels produced by pile-driving. Air streaming from closely spaced release points creates a “wall” of bubbles around the pile. Because air and water have a substantial impedance mismatch, the bubble curtain acts as a reflector. The bubbles also resonate in response to sound and absorb sound energy. Up to a 30 dB reduction in sound has been measured when bubble curtains are deployed with pile driving.
- Lucke et al. 2011, "The use of an air bubble curtain to reduce the received sound levels for harbor porpoises (Phocoena phocoena)." J. Acoust. Soc. Am. 130 (5): 3406–3412.
- Reyff, J. 2009, "Reducing Underwater Sounds with Air Bubble Curtains." TR News. Transportation Board of the National Academies. 262: 31-33.
- Wursig, B., C. R. Greene, Jr., T. A. Jefferson. 1999, "Development of an Air Bubble Curtain to Reduce Underwater Noise of Percussive Piling." Marine Mammal Research, 49:79–93.
- Reyff, J. A. 2003, "Underwater Sound Levels Associated with Construction of the Benicia-Martinez Bridge: Acoustical Evaluation of an Unconfined Air-Bubble Curtain System at Pier 13." Illingworth & Rodkin, Inc., Petaluma, California.