BACKGROUND

Aquatic pile-driving generates hydroacoustic pressure impulses and particle velocities that can cause effects on fish ranging from altered behavior, hearing loss, and tissue injuries to immediate mortality. The degree to which an individual fish exposed to sound will be affected is dependent in part on factors such as the species, size, and physical condition of the fish; site-specific conditions; and the duration of the fish's exposure to the noise. Fish kills from pile driving have been noted on both coasts and have resulted in unforeseen impacts to sensitive fishery resources, as well as project delays and additional costs. State DOTs, resource agencies, ports, and the private sector must be able to reasonably predict impact levels that will occur during pile and casing installation and removal projects to devise appropriate mitigation measures.

The objective of this project was to develop guidelines for the prediction and mitigation of the negative impacts on fish from underwater sound pressure and particle movement during pile and casing installation and removal.  The study simulated the sound of pile driving in a laboratory environment and studied the impacts on juvenile Chinook salmon.  The final report is available on the TRB website at https://www.trb.org/Publications/PubsNCHRPResearchResultsDigestsAll.aspx, and the appendices can be downloaded here.