HydroacousticsHydroacoustics• ODOT
Hydroacoustic Work Group
• Agreement on Thresholds
• Specifications• Effects to fish• Attenuation• Monitoring and
Reporting• Information needs
for BA
ODOT Hydroacoustic Work Group- HAWG• Members- ODOT,
NMFS, USFWS, ODFW, Construction Firm
• Training• Communication with
stakeholders• Monitoring protocol• Specifications
– Attenuation– Monitoring
• Research• Information pool• Website
Specifications
00290.34(c)
• (7) Hydroacoustic:
• (a) General: Hollow steel piling or H‑pile may be installed below the ordinary high water as follows:
• (b) Noise Attenuation System: Contractor shall use a confined bubble curtain system for all pile driven with an impact hammer in the wetted perimeter and conforming to the following minimum requirements:
• (c) Underwater Noise Monitoring Plan, Monitoring, and Reporting: Submit an Underwater Noise Monitoring Plan to the Project Manager (PM) for review and approval at least 10 Calendar Days
Protruding internal organs
Rupture of the body cavity
Ruptured kidneys
Ruptured swim bladder
Internal bleeding
Abdominal scale loss
Project Title
Pile information (size, type, number, pile strikes, etc.)
Fill in green cells: estimated sound levels and distances at which they were measured, estimated number of pile strikes per day, and transmision loss constant.
Acoustic Metric
Peak SEL RMS Effective Quiet
Measured single strike level (dB) 208 175 195 150
Distance (m) 10 10 10
Estimated number of strikes 3750
Cumulative SEL at measured distance
211
Distance (m) to threshold
Onset of Physical Injury Behavior
Peak Cumulative SEL dB** RMS
dB Fish ≥ 2 g Fish < 2 g dB
Transmission loss constant (15 if unknown) 206 187 183 150
15 14 383 464 10000
** This calculation assumes that single strike SELs < 150 dB do not accumulate to cause injury (Effective Quiet)
30000
20000
10000
0
-10000
-20000
-300000 0.02 0.04 0.06 0.08
Time (sec)
Pre
ssu
re (
Pa)
Effect of Bubble Curtain on Pressure
Confined Bubble Curtain
Confined Bubble Curtain
Pile SleevePile Sleeve
Bubble RingBubble Ring
Must extendMust extendabove surfaceabove surface
Must contact bottomMust contact bottom
New TNAP (Megatron)New TNAP (Megatron)
Thicker Thicker Pile SleevePile Sleeve
Bubble RingBubble Ring
Closed Cell Closed Cell Foam LiningFoam Lining
Monitoring and Reporting
• Which projects need monitoring?
• WSDOT Protocolhttp://www.wsdot.wa.gov/Environment/
Biology/BA/default.htm#UnderwaterNoise
• ODOT Protocol• Reporting
Hydroacoustic monitoring will be conducted during the first five piles struck with an impact hammer, which are driven in water depths that are representative of mid-channel or typical water depths at the project location where piles will be driven. Bathymetry, total number of piles to be driven, depth of water, and distance from shore will also be taken into consideration when choosing representative piles. Hydroacoustic monitoring of steel pile driving will include:
•Measuring underwater ambient levels,
•Monitoring of 5 steel piles (minimum),
•Testing sound attenuation system effectiveness.
WashDOT Monitoring Protocol
Item Specifications Quantity Usage
Hydrophone with 200 feet of cable
Receiving Sensitivity-211dB ±3dB re 1V/µPa
1
Capture underwater sound pressures and convert to voltages that can be recorded/analyzed by other equipment.
Signal Conditioning Amplifier (4-channel)
Amplifier Gain- 0.1 mV/pC to 10 V/pCTransducer Sensitivity Range- 10-12 to 103 C/MU
1Adjust signals from hydrophone to levels compatible with recording equipment.
Calibrator (pistonphone-type)
Accuracy- IEC 942 (1988) Class 1
1Calibration check of hydrophone in the field.
Portable Dynamic Signal Analyzer (4-channel)
Sampling Rate- 24K Hz or greater
1Analyzes and transfers digital data to laptop hard drive.
Microphone (free field type)
Range- 30 – 120 dBASensitivity- -29 dB ± 3 dB (0 dB = 1 V/Pa)
1Monitoring airborne sounds from pile driving activities (if not raining).
Laptop computerCompatible with digital analyzer
1Record digital data on hard drive and signal analysis.
Real Time and Post-analysis software
- 1Monitor real-time signal and post-analysis of sound signals.
Equipment for underwater sound monitoring (hydrophone, signal amplifier, and calibrator). All have current National Institute of Standards and Technology (NIST) traceable calibration.[1]
[1] If acoustic monitoring is conducted by a contractor specialized in hydroacoustic monitoring and not conducted directly by WSDOT, the contractor will submit a detailed equipment list for underwater sound pressure level monitoring for approval by a WSDOT acoustic specialist.
1. Size and type of piles.2. A detailed description of the bubble curtain, including design specifications.3. The impact hammer force used to drive the piles.4. A description of the monitoring equipment.5. The distance between hydrophone and pile.6. The depth of the hydrophone.7. The distance from the pile to the wetted perimeter.8. The depth of water in which the pile was driven.9. The depth into the substrate that the pile was driven.10. The physical characteristics of the bottom substrate into which the piles were
driven.11. The ranges and means for peak, RMS, and SEL’s for each pile.12. The results of the hydroacoustic monitoring, including the frequency
spectrum, peak and RMS SPL’s, and single-strike and cumulative SEL with and without the attenuation system.
13. A description of any observable fish or bird behavior in the immediate area will and, if possible, correlation to underwater sound levels occurring at that time.
Hydroacoustic Monitoring Reports should contain….
Willamette River Bridge- case study
•Hydroacoustic monitoring per WSDOT Hydroacoustic monitoring per WSDOT templatetemplate•Monitoring of 35 piles over three yearsMonitoring of 35 piles over three years•Two hydrophones instead of oneTwo hydrophones instead of one•Monitoring with/without attenuation Monitoring with/without attenuation device ondevice on•Locations representative of varying Locations representative of varying channel conditionschannel conditions
Information needs for the BAInformation needs for the BA
• Vibratory hammer or impact hammer.• Type of pile.• Size of pile <24”>.• Number of piles (in-water/out of water).• Estimated number of pile strikes/day.• Life-history stages present in the Action Area.• Monitoring data from previous projects with similar site
conditions?• Aquatic habitat types where piles will be driven (scour
pools, riffles, etc.).• Substrate data from geo-tech report.• In-water work timing, variance may be needed.
Web links:
• ODOT hydroacoustic website:ftp://ftp.odot.state.or.us/techserv/geo-environmental/Biology/Hydroacoustic/
• WSDOT hydroacoustic information:http://www.wsdot.wa.gov/environment/biology/ba/default.hmt#noise
Illustrations in this presentation courtesy of:Bud Abbot, Environ CorporationJohn Stadler, NMFSJim Laughlin, WSDOTStuart Myers, MB&G