1 / 16

Passive Acoustic Monitoring for Tidal Energy Projects

Passive Acoustic Monitoring for Tidal Energy Projects. Brian Polagye , Chris Bassett, and Jim Thomson University of Washington Northwest National Marine Renewable Energy Center. Ecological and Environmental Monitoring April 7, 2011. Evaluating Acoustic Effects.

vicki
Download Presentation

Passive Acoustic Monitoring for Tidal Energy Projects

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Passive Acoustic Monitoring for Tidal Energy Projects Brian Polagye, Chris Bassett, and Jim Thomson University of Washington Northwest National Marine Renewable Energy Center Ecological and Environmental Monitoring April 7, 2011

  2. Evaluating Acoustic Effects Marine Mammal Behavioral Response to Sound Sound Received by Marine Mammal Context for Received Sound Individual Life History • Sound generated by turbine • Site-specific sound propagation • Marine mammal hearing sensitivity • Ambient noise from other sources • Marine mammal activity state • Exposure to similar sounds

  3. Quantifying Sound from Turbines Nearby shipping • OpenHydro turbine (6 m diameter) • Drifting EARs data collection • Compare drift series to identify turbine-specific features Bedload transport AHD at fish farm Common spectral peaks (100 Hz – 3 kHz) Data collected by Scottish Association of Marine Sciences

  4. Marine Mammal Hearing Sensitivity Turbine Noise Southall et al. (2007) Marine mammal exposure criteria

  5. Implication for Received Levels Broadband Levels Mid-frequency Cetaceans 4x reduction in area ensonified to 120 dB

  6. Stationary Hydrophone Measurements Loggerhead DSG • Autonomous hydrophone (32 GB capacity) • 80 kHz sampling • 2% duty cycle for 3 months

  7. Temporal and Spatial Variability Hydrophone Deployments Cumulative Probability Density Temporal variability dominates over spatial variability

  8. Vessel Traffic Monitoring with AIS • Automatic Identification System (AIS) transponders required on all vessels greater than 300 tonnes gross weight and passenger vessels • Continuous data collection and archiving

  9. Data Assimilation Vessel Proximity Noise Correlation SPL (dB re 1 μPa) Distance to closest vessel (km) Vessel noise drives broadband noise levels Source: Chris Bassett, forthcoming PhD dissertation

  10. Implication for Evaluating Noise Effects

  11. Sound during High Currents Hydrophone Response Current Velocity

  12. Flow Shield Experiment Hydrophone with Flow Shield Unshielded Hydrophone High Velocity Region High Porosity Foam Hydrophone Element Doppler Velocimeter Sample volume aligned with hydrophone element Quiescent Region Hydrophone Pressure Case Source: Chris Bassett, forthcoming PhD dissertation

  13. Pseudo-Sound Identification Unshielded Hydrophone Hydrophone with Flow Shield Source: Chris Bassett, forthcoming PhD dissertation

  14. Propagating Sound during High Currents • Bedload transport • Elevated noise at 5-50 kHz • Consistent with size of gravel and shell hash observed during ROV surveys; O(1 cm) • Turbulent flow over rough surfaces • Potential contribution from advected turbulence • Cannot measure velocity fluctuations directly at frequencies of interest (e.g., > 300 Hz) (Hz) (Thorne, 1986) Source: Chris Bassett, forthcoming PhD dissertation

  15. Measuring Noise from Tidal Turbines Long-term, low-intensity monitoring Short-term, spatial characterization

  16. Thank You • This material is based upon work supported by the Department of Energy and Snohomish County PUD under Award Number DE-0002654. Joe Talbert for keeping all equipment in working order. Sam Gooch, Joe Graber, and Alex DeKlerk for helping turn around instrumentation. Captains Andy Reay-Ellers for piloting skills during instrumentation deployment.

More Related