Reducing Inwater Pile Driving Sound - What Are My Options?

Decreased unit costs and increased seismic standards have led to a preference for steel piles for a variety of coastal and transportation infrastructure projects. However, driving these piles can generate inwater sounds that disturb or harm aquatic wildlife. Compliance with inwater sound thresholds for many protected species can have substantial impacts on inwater project construction methods, schedules, and costs- sometimes requiring challenging and expensive sound minimization measures. These measures may include working within specified work windows, monitoring sound and biological levels, deploying sound attenuation devices (e.g. bubble curtains, cofferdams, etc.), and using alternative pile driving methods (e.g. drilling, suction pile driving, etc.). There are advantages and disadvantages for each of these minimization options, and their effectiveness, suitability, cost, and schedule implications (both direct and indirect) vary. This paper provides a brief background on inwater sound reduction and summarizes the steps that an applicant can take to identify which measures would best complement their project.