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Assessing the Effects To Fish From Pile Driving: Application of New Hydroacoustic Criteria February 25, 2009 David Woodbury NMFS, Southwest Region Protected.

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Presentation on theme: "Assessing the Effects To Fish From Pile Driving: Application of New Hydroacoustic Criteria February 25, 2009 David Woodbury NMFS, Southwest Region Protected."— Presentation transcript:

1 Assessing the Effects To Fish From Pile Driving: Application of New Hydroacoustic Criteria February 25, 2009 David Woodbury NMFS, Southwest Region Protected Resources Division and John Stadler NMFS, Northwest Region Habitat Conservation Division

2 Photo courtesy of Bud Abbott Fish injury Basics of Sound HistoryAnalysis Information needs Minimization Measures Next Steps

3 California San Francisco-Oakland Bay Benicia-Martinez Bridge 8 ft dia. hollow steel piles Impact hammer Kilojoules California San Francisco-Oakland Bay Benicia-Martinez Bridge 8 ft dia. hollow steel piles Impact hammer Kilojoules Recent Fish-Kills Vancouver, BC 36” dia. hollow steel piles Impact hammer Vancouver, BC 36” dia. hollow steel piles Impact hammer Species Killed Sturgeon Plainfin midshipmen Tom cod SalmonidsHerringAnchoviesSardinesSmelt Surfperches – 3 spp. Striped bass Rockfishes Species Killed Sturgeon Plainfin midshipmen Tom cod SalmonidsHerringAnchoviesSardinesSmelt Surfperches – 3 spp. Striped bass Rockfishes Puget Sound Mukilteo Ferry Terminal – 2001, 2006 Winslow Ferry Terminal Port of Seattle (2 reports) Bremerton Ferry Terminal ” dia. hollow steel piles Impact hammer Puget Sound Mukilteo Ferry Terminal – 2001, 2006 Winslow Ferry Terminal Port of Seattle (2 reports) Bremerton Ferry Terminal ” dia. hollow steel piles Impact hammer

4 (D. Desjardin, 2003) Barotrauma External Internal (D. Desjardin, 2003)

5 Underwater Sound Sound Pressure Waves Emanating from pile Sound Pressure Waves Emanating from pile Overhead View Pressure Time Overpressure Underpressure Waveform

6 The “Gong Show” Theory SB Strains swimbladder and puts pressure on internal organs Sharper and louder sounds increase amplitude SB Sound pressure wave is the “hammer” Swimbladder is the “gong” Vibrates at resonant frequency ~ 800 Hz Expands and contracts

7 Root Mean Square – RMS Quadratic mean of the pressure Square root of the mean of the squares of the pressures An “average” over the signal dB re 1 µPa Pertinent Underwater Sound Metrics Peak Pressure Max absolute value instantaneous pressure dB re 1 µPa Peak P P Time RMS

8 Sound Exposure Level (SEL) Area under the curve Time-Integrated Sound-Pressure-Squared dB re 1 µPa 2 sec Pressure Time

9 Decibels Actual Quantity:pressure (psi, µPa), µPa 2 sec Expressed as dB (reference quantity) Peak SPL of 180 dB re 1 µPa Without metric and reference value, dB value is useless

10 SEL cum = SEL ss + 10Log(#strikes) Example: SEL ss = 180 dB re 1µPa 2 sec at 10 meters from pile 1000 pile strikes SEL cum = Log(1000) = = 210 dB re 1µPa 2 sec SEL cum = SEL ss + 10Log(#strikes) Example: SEL ss = 180 dB re 1µPa 2 sec at 10 meters from pile 1000 pile strikes SEL cum = Log(1000) = = 210 dB re 1µPa 2 sec Calculate Cumulative SEL

11 Geometrical Spreading Same Energy Distributed Over Larger Surface Area Larger Surface Area = Lower Energy Density Geometrical Spreading Same Energy Distributed Over Larger Surface Area Larger Surface Area = Lower Energy Density

12 Transmission Loss (TL) Sound attenuates with distance from source Geometrical Spreading Absorption/Scattering Transmission Loss (TL) Sound attenuates with distance from source Geometrical Spreading Absorption/Scattering TL(dB) = B Log (R 1 /R 0 ) + α R Where: TL= Transmission Loss in dB B= Geometric Spreading Constant R 1 = Distance to sound level estimate R 0 = Distance of known sound level α R= Absorption and Scattering -IGNORE

13 Transmission Loss Practical spreading loss model (aka the “15 Log” model) TL(dB) = 15 Log (R 1 /R 0 ) ~4.5 dB loss for doubling of distance

14 192 dB dB 183 dB dB 10 m 20 m 40 m 80 m Transmission Loss TL (dB) = 15Log(R 1 /R 0 ) ~4.5 dB decrease for each doubling of distance

15 Received levels Independent of distance 10 meters – no biological significance Applicable to all fish with swimbladders ESA Essential Fish Habitat (EFH) Others Underwater Sound Criteria

16 Injury expected: Peak pressure ≥ 180 dB (re 1µPa) Adverse behavioral response expected if: RMS pressure ≥ 150 dB (re 1µPa) Initial Underwater Sound Criteria

17 Formed in 2004 Participating Agencies FHWA, NMFS, USFWS State DOTs (Caltrans, WSDOT, ODOT) Other agencies and technical experts June 10-11, 2008 Reached an “Agreement in Principle” that established interim criteria for injury to fish from pile driving Fisheries Hydroacoustic Working Group (FHWG)

18 Onset of injury expected if either: Cumulative SEL (size dependent) Fish ≥ 2 grams = 187 dB (re 1µPa 2 sec) Fish < 2 grams = 183 dB (re 1µPa 2 sec) Peak pressure (single strike) ≥ 206 dB (re 1µPa) Adverse behavioral threshold was not addressed and thus remains as: RMS pressure ≥ 150 dB (re 1µPa) Agreement in Principle

19 Example: Single Strike SEL = m SEL Accumulation - 1 Strike 180 dB 175 dB 171 dB 166 dB

20 SEL Accumulation - 10 Strikes 190 dB 185 dB 181 dB 176 dB Example: Single Strike SEL = m

21 SEL Accumulation Strikes 200 dB 195 dB 191dB 186dB 74 Example: Single Strike SEL = m

22 187 dB 340 m SEL Accumulation Strikes 210 dB 205 dB 201 dB 196 dB Example: Single Strike SEL = m

23 How Many Strikes Do We Count? All strikes during the project? ……………in a day? ……………in an hour? Need to consider: Pre-injury tissue recovery Little known about recovery time Fish behavior Are the fish stationary? Are the fish migrating through the area? General Rule: reset calculation after 12 hour break in pile driving

24 Effective Quiet The minimum single-strike SEL that accumulates 150 dB SEL X X X

25 1.Calculate the distance from pile where effects are expected 2.Calculate area affected 3.If data on fish density, then calculate number of fish affected How do we use these criteria?

26 Behavioral Disruption 150 dB RMS Behavioral Disruption 150 dB RMS Distances/Areas/# Fishes to Calculate Onset of Injury 206 dB peak or 183 dB dB SEL Onset of Injury 206 dB peak or 183 dB dB SEL

27 Estimating Distance to Threshold 1.Obtain estimates for various metrics at known distance from pile Use Caltrans’ Compendium For SEL, need estimate of pile strikes/day Consider attenuation measures 2.Use transmission loss model to calculate distance to threshold Estimating Distance to Threshold 1.Obtain estimates for various metrics at known distance from pile Use Caltrans’ Compendium For SEL, need estimate of pile strikes/day Consider attenuation measures 2.Use transmission loss model to calculate distance to threshold

28 Estimating SEL Single Strike SEL ≈ Peak – 26 dB

29 Distance to Threshold TL(dB) = 15 Log (R 1 /R 0 ) R 1 = R 0 10 (TL/15) Where: TL = estimated sound at distance R 0 minus threshold value R 0 = distance sound was recorded from pile if RMS = 180 dB at 10 m (R 0 ) TL= 180 – 150 = 30 dB R 1 = 10 m 10 (30/15) = 1000 m

30 Example Calculations R 1 = R 0 10 (TL/15) Example Calculations R 1 = R 0 10 (TL/15) Peak:204 10m 10 m*10 (( )/15) = 7 m SEL:SEL ss = m, 100 pile strikes SEL cum = Log(100) = 198 dB All fish > 2 g 10 m*10 (( )/15) = 54 m RMS: m 10 m*10 (( )/15) = 4642 m

31 Peak = 204 dB Cumulative SEL = 198 dB RMS = 190 dB SEL > 187dB 54 m RMS > 150 dB 4642 m Peak > m

32 NMFS Spreadsheet Calculates Distances to Thresholds NMFS Pile Driving Calculations xls

33 Expected Peak, SEL, and RMS Include sound attenuation measures Number of strikes per summation period Usually per day Behavior of fish Stationary vs Migrating Assume stationary if not sure Size of fish in area Information Needs

34 1.Verify estimated sound levels Especially important with large impacts New location New pile size 2.Verify effectiveness of minimization measures Are performance standards being met? New/unproven designs New location Inexperienced contractor Necessary to ensure authorized take is not being exceeded Hydroacoustic Monitoring When is it needed?

35 Standardized methods important 10 meters from pile, at mid-depth See WSDOT guidance at Hydroacoustic Monitoring How?

36 Underwater Sound Minimization Measures WSDOT

37 Water/air density discontinuity attenuates the pressure wave Proven to be cost-effective and easy to deploy Attenuation up to 28 dB 96% reduction in pressure Fish-kills reduced or eliminated Water/air density discontinuity attenuates the pressure wave Proven to be cost-effective and easy to deploy Attenuation up to 28 dB 96% reduction in pressure Fish-kills reduced or eliminated Bubble Curtain Pile Perforated Conduit Air supply lines

38 Unconfined Bubble Curtain Bubble Ring Best in low current areas Additional rings In deeper water or higher currents Used successfully in California Bubble tree – dB attenuation

39 Unconfined Bubble Curtain Mukilteo dB attenuation Anacortes 3-11 dB attenuation Substrate differences?

40 Mukilteo – Unconfined Bubble Curtain

41 Confined Bubble Curtain Pile Sleeve Bubble Ring Must extend above surface Must contact bottom

42 Benicia Martinez Bridge – Confined Bubble Curtain

43 0-5 dB attenuation 2 feet depth Steel pile guides contacted sleeve 0-5 dB attenuation 2 feet depth Steel pile guides contacted sleeve Yakima River – Confined Bubble Curtain WSDOT 2005

44 Confined Bubble Curtain Eagle Harbor, WA PVC pile sleeve Inflatable boat bumpers for spacers Bubble ring at bottom 12 dB to 14 dB attenuation WSDOT 2005

45 Mukilteo Ferry Terminal Temporary Noise Attenuation Pile (TNAP) TNAP 1 Hollow walled pile sleeve dB attenuation VERY heavy Fish killed when wall leaked TNAP 1 Hollow walled pile sleeve dB attenuation VERY heavy Fish killed when wall leaked TNAP 2 2-inch closed-cell foam liner dB attenuation VERY heavy TNAP 2 2-inch closed-cell foam liner dB attenuation VERY heavy WSDOT

46 Time (sec) Pressure (Pa) Effect of Bubble Curtain on Pressure

47 Without Bubble Curtain For Illustrative Purposes (Not to Scale) “Adverse Effects” to 15 Fish

48 With Bubble Curtain For Illustrative Purposes (Not to Scale) “Adverse Effects” to 6 Fish

49 Other Minimization Measures Dewatered coffer dam or pile sleeve In water work windows Vibratory hammer Drive outside wetted perimeter/above tide Other Minimization Measures Dewatered coffer dam or pile sleeve In water work windows Vibratory hammer Drive outside wetted perimeter/above tide

50 Where To Get This Information? Caltrans and WSDOT websites FHWG Interim Criteria Agreement Compendium of Pile Driving Sound Data NMFS Spreadsheet NMFS – (707)

51 Next Steps FHWG Technical Team Developing table regarding fish size/time/space Sub-injurious effects Literature Review Meets quarterly Research NCHRP study Monitoring


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