A hand-held tool for rapid assessment of underwater sound to inform decision making
Peter H. Dahl* (1,2)
David R. Dall’Osto (1)
Measurements of underwater noise from pile driving are typically required during marine pile driving operations, to inform placement of marine mammal observers and adhere to Incidental Harassment Authorization (IHA) requirements.
A hand-held device, called the Underwater Sound Level Meter (USLM), was designed and built by the University of Washington Applied Physics Laboratory to facilitate this task. The USLM was initially developed to support environmental monitoring efforts by the Washington State Dept. of Transportation with usage now since expanded to include Navy and private efforts.
The USLM employs an intuitive operating menu, requires no specialized training, and rapidly delivers fully calibrated results expressed in the relevant metric, such as peak level, rms level and sound exposure level . Examples from USLM field use will be discussed involving the documentation of isopleths associated with acoustic thresholds defining of injury and behavioral effects for marine mammals. Stakeholders in both industry and government share the same goal of rapid, calibrated measurements of underwater noise to protect marine life and comply with statuary environmental regulations. The USLM is a time and labor saving device that meets this goal.
(1) Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105
(2) Mechanical Engineering Department, University of Washington, 3900 Northeast Stevens Way, Seattle, 98195