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

Interim Threshold Agreement

Interim Threshold Agreement

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)

Attenuation

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

Hydroacoustic Monitoring Locations

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