Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Reply Evidence

2012 Marine Acoustic Supplement

ENBRIDGE NORTHERN GATEWAY PROJECT

Prepared for:

Enbridge Northern Gateway Pipelines

Prepared by:

Stantec Consulting Ltd. Stantec Consulting Ltd. 4370 Dominion Street, Suite 500 Burnaby, BC V5G 4L7 Tel: (604) 436-3014; Fax: (604) 436-3752

July 2012 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Table of Contents

1 Introduction and Background ...... 1-1 2 Marine Acoustics 2011 Technical Data Report, Parts I and II ...... 2-1 2011 TDR—Part I ...... 2-1 2011 TDR—Part II ...... 2-1 3 Killer Whale-Specific Hearing Threshold Weighting Methodology ...... 3-1 4 Summary of Underwater Acoustic Studies and Implications for the May 2010 Application’s Assessment and Conclusions ...... 4-1 4.1 Background on the 2006, 2010, and 2011 Acoustic Modelling Study Technical Data Reports ...... 4-1 4.1.1 Marine Acoustics (2006) Technical Data Report ...... 4-1 4.1.2 Marine Acoustics Modelling Study 2010 Technical Data Report...... 4-2 4.1.3 Marine Acoustics 2011 Technical Data Report (Section 2 of this Supplement) ...... 4-2 4.2 Conclusions Presented in the May 2010 Application ...... 4-3 4.3 Implications for the May 2010 Application’s Conclusions ...... 4-4 4.3.1 Factors Influencing the Conclusions...... 4-4 4.3.2 Influence of the 2011 TDR on Application’s Conclusions for the CCAA ...... 4-7 4.3.3 Influence of the 2011 TDR on the May 2010 Application’s Conclusions for the OWA ...... 4-8 4.3.4 Influence of the Killer Whale-specific Threshold Evaluation on the Application’s Conclusions for the CCAA and OWA ...... 4-8 4.4 Conclusions ...... 4-9 4.5 References ...... 4-10 List of Tables

Table 4-1 Comparison of Predicted Tanker Specifications ...... 4-5 Table 4-2 Summary of Changes to Estimated Area of Behavioural Change Based on 120 dB Contour, Calculated in the 2006, 2010, and 2011 TDRs ...... 4-6

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1 Introduction and Background Written evidence filed by various intervenors raised issues regarding the methods used in the assessment (the May 2010 Application, Volumes 6B and 8B) of potential effects from underwater noise on marine mammals, specifically: 1. Acoustic modelling was based on literature values for vessel sound source levels and may not have used appropriate surrogate levels. Modelling did not account for the effect of sound-quieting technologies. • Gitga’at First Nation—Review of the Enbridge Northern Gateway Project Submission to the Joint Review Panel and Assessment of Project Effects on Gitga’at Natural Resource Values; NEB Reference Number: A2K4X0; Section 4.2.2.1 Harassment due to vessel noise and traffic; Adobe Page 103 • Raincoast Conservation Foundation—Written Evidence of Raincoast Conservation Foundation, Part 2: Marine Impacts – Marine Mammals; Attachment E: Submission of the Natural Resources Defense Council to the Enbridge Northern Gateway Project Joint Review Panel – Regarding Underwater Noise Impacts from Northern Gateway Tanker Traffic; NEB Reference Number: A2K3I0; Section V. Mitigation and Its Limits; Adobe Page 8 2. The Application does not provide the methods behind the killer whale species-specific threshold that was developed. This is required to assess the appropriateness of its use. • Raincoast Conservation Foundation—Written Evidence of Raincoast Conservation Foundation, Part 2: Marine Impacts – Marine Mammals; Attachment E: Submission of the Natural Resources Defense Council to the Enbridge Northern Gateway Project Joint Review Panel – Regarding Underwater Noise Impacts from Northern Gateway Tanker Traffic; NEB Reference Number: A2K3I0; Section II. Behavioral Impacts; Adobe Page 3 and 4. This report addresses these points and is organized into the following sections: • Section 2 addresses the first point above and presents two new reports based on a field study that Northern Gateway conducted in Valdez, Alaska to improve the accuracy of the acoustic modelling parameters. The first report presents the methods for this acoustic field study. The second report uses the new source levels obtained in Alaska to re-model and to update the Marine Acoustics (2006) Technical Data Report modelling scenarios and correct a projection error in the acoustic figures presented in the May 2010 Application. Collectively, these two reports make up Parts I and II, respectively, of the Marine Acoustics 2011 Technical Data Report, which is referred to throughout this supplement as the 2011 TDR. • Section 3 addresses the second point above and presents an explanation of the weighting method used in developing the killer whale species-specific threshold. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

• Section 4 presents: • a summary of all acoustic technical data reports associated with the May 2010 Application (i.e., previously filed and those in this supplement), and • a brief analysis of how the assessment and associated conclusions presented in the May 2010 Application are affected by 1) results of the Alaska field study, 2) an erratum pertaining to related mapping results presented in the Marine Acoustics (2006) Technical Data Report, 3) updates to the Marine Acoustics (2006) Technical Data Report modelling scenarios, and 4) the killer whale species-specific behavioural change threshold. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

2 Marine Acoustics 2011 Technical Data Report, Parts I and II Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

2011 TDR—Part I Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Northern Gateway Pipeline Project: Tanker and Escort Tug Source Level Measurement Study

Valdez Alaska 2010

Prepared for: Stantec Consulting Ltd. for Northern Gateway Pipeline Project

Prepared by: Alexander MacGillivray

JASCO Applied Sciences 2101 – 4464 Markham St. Victoria, British Columbia, V8Z7X8 +1.250.483.3300

2010

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Suggested citation: MacGillivray, A. 2010. Northern Gateway Pipeline Project: Management Tanker and Escort Tug Source Level Measurement Study, Valdez Alaska, 2010. Technical report prepared for Stantec Consulting Ltd. for Northern Gateway Pipeline Project by JASCO Applied Sciences, November 2010.

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Acronyms and Abbreviations µPa Micropascal AIS Automated Identification System AKDT Alaska Daylight Time ASD Azimuth Stern Drive propulsion CPA Closest Point of Approach dB Decibels DWT Deadweight Tons FFT Fast Fourier Transform GEM Gateway Environmental Management program GPS Global Positioning System G-S Grain-Shearing model HP Horsepower Hz Hertz kHz Kilohertz kts Knots MBSF Metres Below Seafloor OBH Ocean Bottom Hydrophone recorder PE Parabolic Equation model PSD Power Spectral Density SL Source Level SNR Signal-to-Noise Ratio SPL Sound Pressure Level TAPS Trans-Alaska Pipeline System TL Transmission Loss VHF Very-High Frequency radio VSP Voith-Schneider Propulsion

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1. Introduction This technical report presents opportunistic acoustic measurements of a tanker and two escort tugs, which were collected by JASCO Applied Sciences in support of the Northern Gateway Pipeline (NGP) Project. Source level data presented in this report were obtained via passive acoustic monitoring of shipping traffic from the Trans-Alaska Pipeline System (TAPS) terminal located in Valdez, Alaska. Acoustic data were collected during 19-21 July 2010 in Port Valdez and in Valdez Arm using an autonomous seabed recorder. The purpose of this study was to obtain direct measurements of tanker (193,000 DWT large crude carrier) and escort tug (VSP and ASD) source levels to verify the suitability of literature source levels used in JASCO’s 2006 (Austin et al.) and 2010 (Chorney et al.) modelling studies. The objective of this study was to obtain opportunistic acoustic measurements for the following marine operations: 1. Voith-Schneider Propulsion (VSP) escort tug at nominal transit speed 2. Azimuth Stern Drive (ASD) escort tug at nominal transit speed 3. Tanker transiting in channel 4. Tanker berthing with escort tugs 5. Tanker loading at terminal Measurements of tanker escort operations (1-3) were successfully obtained during the monitoring study and are presented in this technical report. Specifications for the opportunistically measured vessels were obtained from AIS transmissions and from online resources (Table 1). Due to interference from other noise sources in the harbour, measurements of terminal operations (4-5) could not be obtained from outside the security zone surrounding the terminal. For those operations that were successfully recorded, this technical report presents comparisons of opportunistically measured source levels to data obtained from literature sources that were used in the prior modelling studies.

Table 1: Specifications for opportunistically measured vessels, including propulsion, dimensions, and nominal draft. Vessel Class Propulsion Power Length Beam Draft (m) (HP) (m) (m) Alaskan Large Crude Fixed screw — 287 50 11.0 Legend Carrier (193,000 (unloaded) DWT) 18.8 (loaded) Tanerliq Escort Tug Voith-Schneider 10,192 45 15 7.3 (VSP) (maximum) Aware Escort Tug Azimuth Stern Drive 10,192 43 14 6.0 (ASD)

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2. Methods 2.1. Equipment 2.1.1. OBH recorder Acoustic measurements were obtained using a JASCO Ocean Bottom Hydrophone (OBH) recorder system. The OBH system is a self-contained autonomous underwater acoustic recorder that is deployed on the seabed with a sacrificial anchor weight. The OBH system was deployed with a single Reson TC4032 (−170 dB re µPa/V) reference hydrophone. A GRAS 42AA pistonphone (136 dB re 1 µPa, 250 Hz) was used to calibrate the sensitivity of the OBH recorder prior to each deployment. Single-channel acoustic waveform recordings were digitally acquired at 48 kHz sample rate with 24-bit resolution. 2.1.2. AIS receiver Time stamped logs of vessel IDs, coordinates, headings, and speeds were recorded using a portable AIS (Automated Identification System) receiver station. This consisted of a SmartRadio dual-band AIS decoder with a VHF whip antenna connected via a RS232 serial to a laptop computer with ShipPlotter logging software. Additional web-based AIS monitoring software was used to augment the portable AIS system. Continuous logging of AIS data permitted monitoring of large vessel traffic in Port Valdez during the study. Speeds and positions broadcast on AIS are based on GPS and are expected to have attendant precision. Dimensions and drafts of vessels are also broadcast on AIS, with metre and decimetre precision, respectively. 2.2. Field Recording Procedures For the opportunistic measurements, the OBH recorder was deployed at two locations, designated V1 and V2 respectively, as shown in Figure 1. A charter vessel was used to deploy and recover the OBH recorder. GPS coordinates and deployment times are shown in Table 2. Depths at the recorder locations were recorded to metre precision using the echo-sounder aboard the charter vessel. Station V1, situated in Port Valdez between the west narrows and the tanker terminal, was intended to capture noise from tugs and tankers transiting in the harbour. Station V2, situated on the southbound tanker traffic lane in Valdez Arm, was intended to capture noise from the loaded tanker as it departed the port. Approximately one day of data were recorded at each station. AIS data from vessel traffic were logged continuously during the measurement period. Additional vessel-based hydrophone recordings were attempted outside the security zone across from the TAPS terminal. However interfering noise from intensive fishing boat traffic in the harbour prevented sampling of sound originating from the terminal operations.

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Table 2: OBH recorder deployment stations in Port Valdez (V1) and Valdez Arm (V2). Station Water Depth (m) Latitude Longitude Deployment Recovery Time Time (AKDT) (AKDT) V1 250 N61° 05.754’ W146° 31.915’ 17:23 18:00 19/Jul/2010 20/Jul/2010 V2 195 N60° 54.498’ W146° 55.327’ 19:10 18:30 20/Jul/2010 21/Jul/2010

Figure 1: Nautical chart showing OBH recorder deployment locations in Port Valdez (V1) and in Valdez Arm (V2).

2.3. Acoustic Data Processing Segments of acoustic recordings were identified based on times when TAPS vessels (Table 1) transited past the OBH recorder. Visual and textual AIS logs of vessel positions were manually reviewed to select all periods when large tankers (> 160,000 DWTs) or their escort tugs (VSP or ASD) were entering or departing the harbour. The acoustic waveform data were analyzed using Fast-Fourier-Transforms (FFTs) to compute power spectral density (PSD) versus time in 1 second windows with 50% overlap. The FFT frequency bin size was 1 Hz and FFTs were Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

shaded using a power-normalized Hanning window function. Mean vessel source spectra were estimated by averaging one-second PSD values inside a 90 second time window corresponding to the closest point of approach (CPA) of the vessel to the recorder. Third-octave band sound pressure levels (SPLs) were computed by numerical integration of the mean spectra in standard third-octave pass-bands over the 90 second averaging period. Time-averaging smoothes out variability in measured SPLs caused by sea-surface interference effects (Ross, 1979, §4.6). While the acoustic signature of a vessel travelling at constant speed is generally stable over time, measured SPLs vary considerably as the vessel moves with respect to a fixed hydrophone receiver. The 90 second averaging-time was selected to allow sufficient smoothing of sea-surface interference effects, while minimizing the change in distance to the vessel over the measurement period. The source level estimates are generally obtained from the closest possible distance because the higher sound levels at these times reduce the contaminating influence of background noise. Thus, source level estimates were computed from data segments containing the CPA of the vessel to the recorder. This is standard practice for obtaining acoustic source level measurements of ocean-going vessels. 2.4. Source Level Estimation Procedure 2.4.1. Sound propagation modelling Source levels were computed by subtracting estimated source-receiver acoustic transmission loss (TL) from the measured third-octave band SPLs: this procedure is referred to as “back- propagation”. TL was estimated numerically using a split-step Padé parabolic equation (PE) sound propagation model (Collins, 1993). There are two important advantages of using PE, over simple spherical spreading (i.e., 20 log R), for estimating TL: 1. PE includes the contribution of sound reflected from the sea-surface and seabed, whereas spherical spreading does not. Thus PE-based source levels are expected to be more accurate. 2. Previous underwater noise modelling studies were carried out using a PE model. Using the same model for back-propagation and forward-propagation produces more accurate SPL estimates when source levels are translated to new locations. Transmission loss values from the model were calculated at frequencies above 2 kHz with an additional correction term to account for frequency-dependent sound absorption in seawater. For each third-octave band, mean transmission loss was computed from the average of 10 evenly spaced frequencies inside the pass-band. Averaging over frequency reduces bias in the third- octave band TL values by smoothing out interference nulls. The model takes, as input, source depth, hydrophone depth, source range, and physical descriptions of the sound speed profile and seabed geoacoustic profile. Source and receiver geometry for the transmission loss model was determined from logged AIS positions, estimated source depth, OBH coordinates, and the water depth at the OBH deployment location. In the back-propagation calculation, range is the most influential parameter that determines TL between the source vessel and hydrophone receiver. Back-propagation ranges were expected to be highly accurate (error <3%), since the coordinates of hydrophones and vessels were based on GPS locations. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Source depth is less influential than range in the back-propagation calculation. Nonetheless, the choice of source depth is important at low frequencies (generally below 80 Hz) because, for sources less than ¼ wavelength deep, the radiated acoustic power is significantly reduced due to the proximity of the sea-surface (Brekhovskikh and Lysanov, 2003, §4.14). Although effective source depths for vessels are difficult to estimate precisely since different parts of the hull radiate sound, the dominant source of underwater noise from shipping is generally propeller cavitation (Ross, 1979, §8.6). Therefore, source depths for vessels were based on estimated propeller depth, according to the procedure of Wright and Cybulski (1983), where the source of radiated noise was assumed to be at a point midway between the shaft and the top of the propeller disk. There was necessarily some uncertainty with estimating source depths for vessels of opportunity. Errors in the effective source depth, however, are expected to be largely cancelled out by using the same value for back-propagation modelling and subsequent forward propagation modelling. For multi-vessel scenarios, where it was not possible to separate noise originating from different sources (c.f., 3.1.2 and 3.1.3), it was necessary to use the mean range and source depth in the back-propagation calculation. This effectively assumes that noise from the different vessels originates from a single point. This assumption is clearly more accurate when the ranges and effective source depths of the vessels are similar. Uncertainties associated with this assumption are discussed in more detail in section 3.2. 2.4.2. Environmental model The PE model requires an environmental description of the ocean and seabed acoustic properties to generate transmission loss estimates. A brief literature search found no information regarding the seabed geoacoustics in Port Valdez and Valdez Arm. The seabed sediments were assumed to be terrigenous silty-sand, due to reported alluvial sediment deposition in the fjord basin (Palmer, 1982). Geoacoustic properties of the seabed (Table 3) were computed using the Grain-Shearing (G-S) model of Buckingham (2005). The G-S model is used to compute the sound-speed, density, and attenuation of marine sediments (i.e., sands, silts, and clays), based on their porosity and grain size. Porosity and grain size values used in the G-S model were based on typical mean values for sediments classified as “silty-sand”. No ground truth data were available for the geoacoustic model, but it is estimated that changing the seabed geoacoustics to a less reflective (e.g., silt) or more reflective (e.g., rock) type could increase or decrease the resulting TL estimates by ±3 dB. The silty-sand bottom-type that was used for the back-propagation represents an intermediate case between these two extremes. Data regarding the temperature and salinity stratification of the water column were also unavailable, so the sound velocity profile was assumed to be a uniform 1480 m/s, a common value for sound speed in cold water. This parameter does not have a strong influence on sound propagation at short ranges and, therefore, was not expected to significantly influence the computed transmission loss estimates. An example of modelled transmission loss at the V2 station in Valdez Arm is shown in Figure 2. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Table 3: Geoacoustic seabed model used for back-propagating tug and tanker source levels. MBSF = meters below seafloor. Geoacoustic parameters are density (ρ), P-wave velocity (VP), P-wave attenuation (αP), S-wave velocity (VS), and S-wave attenuation (αS). Values in the table were computed using Buckingham’s Grain-Shearing model, based on typical mean grain-size and porosity values for sediments classified as “silty-sand”.

Porosity Grain Size ρ VP αP VS αS MBSF (%) (φ) (kg/m3) (m/s) (dB/λ) (m/s) (dB/ λ) 1 43.86 4.35 1973.4 1610.6 0.333 117.1 0.039 5 43.86 4.35 1973.4 1668.4 0.559 200.2 0.112 10 43.86 4.35 1973.4 1706.3 0.695 252.3 0.175 20 43.86 4.35 1973.4 1755.9 0.860 317.9 0.273 50 43.86 4.35 1973.4 1846.0 1.126 431.4 0.486 100 43.86 4.35 1973.4 1939.6 1.364 543.5 0.741

Figure 2: Example plot of transmission loss versus range and depth as computed by PE model at f=100 Hz for the Valdez Arm V2 station. Bathymetry is constant zB=296 m out to r=765 m range and slopes up to zB=195 m at r=1530 m range. Source depth is zS=7.5 m and receiver depth at r=1530 m is zR=193 m.

3. Results 3.1. Acoustic Measurements 3.1.1. VSP escort tug The VSP escort tug Tanerliq transited westbound past station V1 at 00:41 AKDT on 20 July 2010. According to AIS logs, Tanerliq was travelling at a speed of 9.3 knots past the OBH recorder. PSD spectra versus time were computed for 17 minutes of acoustic data during the transit of the vessel past the recorder (Figure 3). The mean PSD spectrum (Figure 3 inset) was computed inside a 90 second window corresponding to Tanerliq’s closest approach to the recorder. The mean horizontal range to the vessel over the averaging window was 440 m. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 3: Plot of PSD vs. time during transit of VSP escort tug Tanerliq past the OBH recorder at station V1. Inset plot shows the mean PSD versus frequency for a 90 second time window delineated by the horizontal lines and corresponding to the times the vessel passed at 440 m mean horizontal range from the recorder. Transit speed of Tanerliq during the recording was 9.3 knots.

3.1.2. Tanker (unloaded) and VSP escort tug The tanker Alaskan Legend and VSP escort tug Tanerliq transited eastbound past station V1 at 10:36 AKDT on 21 July 2010. According to AIS logs, the two vessels were travelling at a speed of 12.6 knots past the OBH recorder. Both vessels passed by the OBH recorder at the same distance. PSD spectra versus time were computed for 10 minutes of acoustic data during the transit of the two vessels past the recorder (Figure 4). The mean PSD spectrum (Figure 4 inset) was computed inside a 90 second window corresponding to the time of closest approach of both vessels to the recorder. The mean horizontal range to the vessels was 600 m over the averaging window. The source signatures of the two vessels could not be separated since they were travelling only 400 m apart from each other. Therefore the mean PSD spectrum represents the combined signatures of Alaskan Legend and Tanerliq together. The CPA of the two vessels past the recorder occurred at the 310 s mark in Figure 4. The green intensity peak at the 500 s mark corresponds to an unrelated fishing vessel that transited past the recorder shortly after the tanker.

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Figure 4: Plot of PSD vs. time during transit of tanker Alaskan Legend (unloaded) and VSP escort tug Tanerliq past the OBH recorder at station V1. The higher levels centred at 520 s are due to a fishing vessel that transited past the recorder behind the tanker and tug. The horizontal lines delineate the time window used for source level calculations. Inset plot shows the mean PSD versus frequency for the 90 second window at 600 m mean horizontal range. Transit speed of the vessels during the recording was 12.6 knots.

3.1.3. Tanker (loaded) with two escort tugs (VSP and ASD) The tanker Alaskan Legend, VSP escort tug Tanerliq, and ASD escort tug Aware transited southbound past station V2 at 10:20 AKDT on 22 July 2010. The three ships were accompanied by a small pilot boat, Baranof II (which is not expected to contribute notably to the acoustic signature of the tanker escort operation). According to AIS logs, the vessels were travelling at a mean speed of 9.6 knots past the OBH recorder. The three source vessels passed by the recorder at different ranges: 1200 m (Tanerliq), 1500 m (Alaskan Legend), and 1800 m (Aware). PSD spectra versus time were computed for 10 minutes of acoustic data during the transit of the three vessels past the recorder (Figure 5). The mean PSD spectrum (Figure 5 inset) was computed inside a 90 second window corresponding to the time of closest approach of the tanker to the recorder. The mean horizontal range to the tanker was 1500 m over the averaging window. The source signatures of the three vessels could not be separated since they were travelling with only 600 m separation, with the tanker in the center of the convoy. Therefore the mean PSD spectrum represents the combined signatures of Alaskan Legend, Tanerliq, and Aware together. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 5: Plot of PSD vs. time during transit of tanker Alaskan Legend (loaded), VSP escort tug Tanerliq, and ASD escort tug Aware past the OBH recorder at station V2. Inset plot shows the mean PSD versus frequency for a 90 second window delineated by the horizontal lines at 1500 m mean horizontal range from the tanker. Transit speed of the vessels during the recording was 9.6 knots.

3.2. Source Level Estimates Back-propagation of acoustic source levels from measured third-octave band levels was carried out according to the procedure described in Section 2.4. Back-propagation ranges were computed from OBH deployment coordinates and AIS position logs. For the multi-vessel scenarios (3.1.2 and 3.1.3), mean CPA ranges and source depths were used in the back- propagation calculation, as discussed in 2.4.1. For the measurement of the unloaded tanker and VSP tug (3.1.2), this assumption was not expected to introduce significant error into the source level estimate, since the CPA range of the two vessels was the nearly identical. For the measurement of the loaded tanker, VSP tug, and ASD tug (3.1.3), where the separation of the source vessels was 600 m, it is estimated that using the mean range and source depth could introduce an error of ±2 dB in the computed source levels, due to TL differences between the nearest and farthest source. Source and receiver geometries used in the model-based back- Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

propagation calculation are shown in Table 4. Figure 6 shows the resulting third-octave band source levels calculated from the acoustic data presented in the previous sections. One apparently inconsistent observation in Figure 6 is that, in many frequency bands, source levels of Tanerliq operating on its own (at 9.3 kts) were actually higher than source levels of Tanerliq travelling together with Alaskan Legend and Aware (at 9.6 kts). One possible explanation for this anomalous observation is tidal currents. Vessel speeds recorded via AIS represent “speed over ground”, which is not equivalent to actual speed in water when currents are present. Furthermore, the tidal range at Valdez Harbor is 5.5 m and this location is known to have significant tidal currents. According to tide charts, both of these measurements were carried out at times when the vessels were transiting against prevailing tidal currents. The velocity of tidal currents during the two measurements was not known; however, this could be the source of the observed difference. Other factors that would have influenced radiated vessel noise, like engine power and propeller pitch, were also unavailable due to the opportunistic nature of the measurements. Nonetheless, the Figure 6 data indicate that the source level of the VSP tug Tanerliq was not appreciably lower than the propeller-driven vessels.

Table 4: Back-propagation source and receiver geometries used for source level estimates. Vessels measured Speed Mean source Receiver Receiver (kts) depth (m) range (m) depth (m) Tanerliq 9.3 6.0 440 248 Alaskan Legend (unloaded) & Tanerliq 12.6 5.2 600 248 Alaskan Legend (loaded), Tanerliq & Aware 9.6 7.5 1500 193

Figure 6: Third-octave band source level estimates for the three opportunistic measurements collected during the current study. Vessels and transit speeds are indicated in the plot annotation. Source levels are derived from measurements at 440-1500 m range that were back-propagated to 1 m from the source using a PE acoustic model. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

4. Discussion: Source Level Comparisons Two previous technical reports, prepared by JASCO for the NGP project, presented acoustic modelling of underwater noise from tanker and tug traffic associated with the proposed Kitimat marine terminal. The 2006 modelling study (Austin et al.) considered noise from tug and tanker traffic within confined channels, while the 2010 modelling study (Chorney et al.) considered noise from tug and tanker traffic at open water locations. When these studies were prepared, few literature sources were available providing acoustic source levels for tankers and tanker escort tugs. In particular, specific source levels for VSP tugs and ASD tugs, and high-frequency source levels for tankers were unavailable at the time of writing. For the purposes of the 2006 and 2010 modelling reports, surrogate source levels were selected from the literature that matched, as closely as possible, the expected vessels for the Kitimat marine terminal. Table 5 provides details of the model scenarios that were considered in the 2006 and 2010 studies. The current study was undertaken to provide more closely matching source level data for vessel traffic associated with the proposed terminal.

Table 5: Details of 2006 and 2010 model scenarios, including vessel types, speed and power settings, and surrogate sources. # Location Operation Total Surrogate Vessel Details Vessels 1 Kitimat Terminal Berthing with tug assist 5 1 tanker (1) 2 escort tugs (2) 2 harbour tugs (3) 2 Kitimat Terminal Standby 1 1 tanker (4) 3 Kitimat Terminal Dredging 1 1 clamshell dredge (5) 4 Kitkiata Inlet Transiting 8-12 kts 3 1 tanker (1) at reduced power (-5 dB) 2 escort tugs (2) 5 Principe Channel Transiting 8-12 kts 3 1 tanker (1) at reduced power (-5 dB) 2 escort tugs (2) 6 Wright Sound Transiting 8-12 kts 4 1 tanker (1) at reduced power (-5 dB) 3 escort tugs (2) 7 Caamano Sound Transiting 8-12 kts 2 1 tanker (1) at reduced power (-5 dB) 1 ASD escort tug (2) 8 Open Water Transiting 16 kts 2 1 tanker (1) (Triple Island) 1 ASD escort tug (2) 9 Open Water Transiting 16 kts 2 1 tanker (1) (Browning 1 ASD escort tug (2) Passage) 10 Open Water Transiting 16 kts 1 1 tanker (1) (Langara) 11 Open Water Transiting 16 kts 1 1 tanker (1) (Cape St. James) (1) Generic tanker 240 m transiting at 16 kts (Malme et al. 1989) (2) Mean of two offshore tugs (10,600 HP and 6,600 HP) transiting at unknown speed (Hannay et al. 2004) (3) Harbour tug transiting at 6 kts (MacGillivray et al. 2004) (4) Bulk carrier loading at terminal (MacGillivray et al. 2004) (5) Clamshell dredge during dredging operations (Miles et al. 1987)

TAPS tanker and escort tug source levels from the current study were compared to the surrogate source levels used in the prior modelling, to evaluate the suitability of those original surrogates (Figure 7, Figure 8, Figure 9, and Figure 10). It was not possible to compare source levels for berthing, standby, dredging, or unescorted tanker scenarios (1-3 and 10-11 in Table 5), since Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

measurements were not obtained for these operations. For the remaining six scenarios (4-9), it was possible to compare surrogate source levels with Alaskan Legend, Tanerliq, and Aware transiting at 9.6 kts (3.1.3). For four of these model scenarios (6-9), it was necessary to apply corrections to account for differences in transit speeds and quantities of vessels. Source levels were corrected for speed according to the relationship given by Ross (1979, Eqs. 8.34 and 8.35) for radiated cavitation noise from surface ships:

LSʹ = LS + 60log10(vʹ/v) (1)

where LS is the baseline source level, LSʹ is the adjusted source level, and vʹ/v is the ratio of transit speeds. This relationship, which is based on a large collection of historical measurements, is expected to provide conservative speed corrections for measured source levels, although it does not account for changes in noise frequency distribution. For those scenarios where the number of tugs was different, source levels were scaled according to the assumption that total radiated sound power was proportional to the number of vessels involved in an operation:

LSʹ = LS + 10log10(Nʹ/N) (2)

where LS and LSʹ are as above and Nʹ/N is the ratio of the number of vessels. This assumes that the different vessels involved in an operation contribute a roughly equal amount of radiated noise power. If, instead, one vessel were significantly noisier than the others, then the adjusted source level is still expected to be accurate to within ±1.5 dB, depending on the relative contribution of the different ships. Finally, it was necessary to combine (i.e., sum) the source levels of individual surrogates from the 2006 and 2010 studies to provide direct comparisons to composite source levels from the current study. In the cases of the confined channel scenarios (Figure 7, Figure 8, and Figure 9), surrogate source levels from the prior modelling studies were higher in most frequency bands than the TAPS source levels measured during the current study. However, for the open water scenarios (Figure 10) surrogate source levels were lower than the TAPS source levels at frequency bands above 300 Hz, after the correction was applied for increased transit speed. To better quantify the differences, decade-band source levels (low frequency 0.01-0.1 kHz, mid-frequency 0.1-1 kHz, high-frequency 1-10 kHz) were computed from the third-octave band source levels (Table 6). The decade-band comparisons show that the surrogate source levels from the prior modelling were generally conservative for the confined channel scenarios, where they were 7-20 dB greater than the TAPS source levels, depending on the frequency range under consideration. For the open-water scenarios, the surrogate source levels were 7 dB greater than the TAPS source levels at low frequencies, but 3-5 dB lower at mid-to-high frequencies.

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Figure 7: Comparison of TAPS measurements with surrogate source levels for tanker and 2 escort tugs transiting 8- 12 kts in confined channel (model scenarios 4-5 in Table 5). Surrogate data represent summed tanker and tug source levels from 2006 modelling report (Austin et al.). TAPS source levels are for the tanker Alaskan Legend, VSP escort tug Tanerliq, and ASD escort tug Aware transiting at 9.6 kts.

Figure 8: Comparison of TAPS measurements with surrogate source levels for tanker and 3 escort tugs transiting 8- 12 kts in confined channel (model scenario 6 in Table 5). Surrogate data represent summed tanker and tug source levels from 2006 modelling report (Austin et al.). TAPS source levels are for the tanker Alaskan Legend, VSP escort tug Tanerliq, and ASD escort tug Aware transiting at 9.6 kts, with a +1.2 dB adjustment to account for the addition of a third escort tug. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 9: Comparison of TAPS measurements with surrogate source levels for tanker and ASD escort tug transiting 8-12 kts in confined channel (model scenario 7 in Table 5). Surrogate data represent summed tanker and tug source levels from 2006 modelling report (Austin et al.). TAPS source levels are for the tanker Alaskan Legend, VSP escort tug Tanerliq, and ASD escort tug Aware transiting at 9.6 kts, with a -1.7 dB adjustment to account for the absence of the VSP escort tug.

Figure 10: Comparison of TAPS measurements with surrogate source levels for tanker and ASD escort tug transiting 16 kts in open water (model scenarios 8-9 in Table 5). Surrogate data represent summed tanker and tug source levels from 2010 modelling report (Chorney et al.). TAPS source levels are for the tanker Alaskan Legend, VSP escort tug Tanerliq, and ASD escort tug Aware transiting at 9.6 kts, with a -1.7 dB adjustment to account for the absence of the VSP escort tug and a +13.3 dB adjustment to account for the increased 16 kts transit speed (total adjustment +11.6 dB). Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Table 6: Decade-band comparisons of measured source levels for Alaskan Legend, Tanerliq, and Aware with surrogate source levels from prior modelling. Decade band source levels were computed by summing third-octave bands levels inside the specified frequency ranges. Source Level (dB re 1 µPa @ 1 m) Low-frequency Mid-frequency High-frequency 0.01-0.1 kHz 0.1-1.0 kHz 1-10 kHz Tanker and 2 escort tugs transiting 8-12 kts in confined channel (scenarios 4-5) Surrogate vessels (Austin et al. 2006) 189.3 183.7 176.8 TAPS vessels (no adjustment) 169.5 176.9 170.5 Tanker and 3 escort tugs transiting 8-12 kts in confined channel (scenario 6) Surrogate vessels (Austin et al. 2006) 190.9 184.9 178.2 TAPS vessels (+1.3 dB adjustment) 170.7 178.2 171.7 Tanker and ASD escort tug transiting 8-12 kts in confined channel (scenario 7) Surrogate vessels (Austin et al. 2006) 186.7 182.1 174.5 TAPS vessels (-1.7 dB adjustment) 167.7 175.2 168.7 Tanker and ASD escort tug transiting 16 kts in open water (scenarios 8-9) Surrogate vessels (Chorney et al. 2010) 188.1 185.6 176.8 TAPS vessels (+11.6 dB adjustment) 181.0 188.5 182.0

For the 2006 confined channel model scenarios, differences between the surrogate and TAPS source levels, portrayed in Table 6, appear quite large (7-20 dB). The differences can be explained, however, by considering speed and engine power settings assumed in the 2006 modelling. As shown in Table 5, surrogate tanker source levels used in 2006 carried a conservative -5 dB “half-power” correction factor. According to Eq. (1), this corresponds to a transit speed that is higher than that of the TAPS tanker convoy measured at Valdez Arm (13.2 kts versus 9.6 kts). Furthermore, surrogate escort tug source levels were not adjusted in the 2006 modelling, since transit speeds were not quoted for these measurements. Therefore, the surrogate source levels correspond more closely to the upper end of the 8-12 kts vessel speed range, which was specified for the scenarios for the Confined Channel Assessment Area (CCAA). The TAPs values correspond more closely to the middle range of the transit speeds of vessels in the CCAA (i.e., 8-10 kts in the core humpback whale area and 10-12 knots in the remainder of the CCAA). That the surrogate source levels are lower than the TAPS source levels for the open water scenarios, at mid-to-high frequencies, indicates that assumed transit speeds are indeed the main source of the differences. Thus, surrogate source levels from the 2006 study were generally conservative, in terms of total radiated underwater noise, in comparison to the measurements obtained at Valdez.

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

5. Summary and Conclusions This technical report has presented opportunistically collected source level data for tanker and escort tug traffic from the TAPS terminal located in Valdez, Alaska. Source level data were obtained for a tanker (Alaskan Legend), VSP escort tug (Tanerliq), and ASD escort tug (Aware) using an autonomous seabed recorder and AIS vessel tracking system. Source level data collected during the current study are expected to be more closely representative of tug and tanker traffic associated with the proposed Kitimat marine terminal. Measurements of the VSP escort tug obtained at Valdez did not indicate significant noise savings in comparison to conventional propulsion, except possibly at infrasound frequencies (below 40 Hz). Source level data collected during the current study were compared with literature source levels used in two prior modelling efforts carried out in 2006 and 2010. For the 2006 confined channel scenarios, it was found that surrogate literature source levels used in the prior modelling were conservative (7-20 dB greater) across all frequency bands, in terms of estimating total radiated noise from tug and tanker traffic. However, the differences were mostly due to the lower transit speed of the TAPS vessels (9.6 kts) as opposed to the conservative assumptions of the 2006 modelling (13.2 kts). For the 2010 open water scenarios, the TAPS vessels were found to have higher source levels (3-5 dB greater) than the surrogate sources, at mid-to-high frequencies. Source levels at mid-to-high frequencies (> 100 Hz) are expected to be of primary importance in determining vessel noise footprints in any subsequent remodelling efforts.

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

References

Austin, M., A. MacGillivray, D. Hannay, and M. Zykov. 2006. Gateway Environmental Management: Marine Acoustics Study. Technical report prepared for Jacques Whitford Ltd. by JASCO Research Ltd., September 2006. Brekhovskikh, L., and Lysanov, Y., Fundamentals of Ocean Acoustics (3rd ed.). Springer, NY, 278 pp. Buckingham, M., 2005. Compressional and shear wave properties of marine sediments: Comparisons between theory and data. J. Acoust. Soc. Am. 177:137-152. Chorney, N., G. Warner, and M. Austin. 2010. Gateway Environmental Management Vessel Transit Noise, Marine Acoustics Modelling Study, 2010. Version 4. Technical report prepared for Stantec by JASCO Applied Sciences, March 2010. Collins, M.D. 1993. The split-step Padé solution for the parabolic equation method. J. Acoust. Soc. Am. 93:1736- 1742. Hannay, D., A. MacGillivray, M. Laurinolli, and R. Racca. 2004. Sakhalin Energy: Source Level Measurements from 2004 Acoustics Program, Ver. 1.5. Technical report prepared for Sakhalin Energy by JASCO Research Ltd., December 2004. MacGillivray, A., H. Sneddon and D. Hannay. 2004. Underwater Noise Level Measurements at Gravel Loading Facility, Sechelt, British Columbia. JASCO Research report for Polaris Minerals’ Orca Sand and Gravel Project EA submission to B.C. Environmental Assessment Office. Available at: http://www.eao.gov.bc.ca/epic/output/documents/p225/d19527/1106074391306_f1cb72dcf3e7482c9684ca 1e2ec4ec40.pdf Malme, C.I., P.R. Miles, G.W. Miller, W.J. Richardson, D.G. Roseneau, D.H. Thomson, and C.R. Greene Jr. 1989. Analysis and Ranking of the Acoustic Disturbance Potential of Petroleum Industry Activities and Other Sources of Noise in the Environment of Marine Mammals in Alaska. OCS Study MMS 89-0006. Report No. 6945 prepared for U.S. Minerals Management Service, Alaska OCS Region by BBN Systems and Technologies Corp. 304 p. http://www.mms.gov/alaska/reports/1980rpts/akpubs80s.HTM Miles, P.R., C.I. Malme and W.J. Richardson. 1987. Prediction of Drilling Site-Specific Interaction of Industrial Acoustic Stimuli and Endangered Whales in the Alaskan Beaufort Sea. OCS Study MMS87-0084. Report No. 6509. Palmer, H.D., 1981. Recent sedimentation, northeastern Port Valdez, Alaska. Geo-Marine Letters. 1: 207-212. Ross, D., 1979. Mechanics of Underwater Noise. Pergamon Press, NY, 369 pp. Wright, E., and Cybulski, J., Low-Frequency Acoustic Source Levels of Large Merchant Ships, NRL Report 8677, March 1983.

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Appendix A. Third-Octave Band Source Levels

Source: Tanerliq Speed: 9.3 kts Source Depth: 6 m SL (dB re 1 µPa @ 1 m): 178.613 Frequency (kHz) SL (dB re 1 µPa @ 1 m) 0.005 145.275 0.006 140.667 0.008 155.178 0.010 152.719 0.013 160.893 0.016 156.327 0.020 157.137 0.025 161.357 0.032 159.272 0.040 159.073 0.050 167.368 0.063 170.039 0.079 160.919 0.100 158.380 0.126 162.378 0.158 156.741 0.200 158.852 0.251 169.369 0.316 167.361 0.398 168.158 0.501 169.272 0.631 160.737 0.794 169.808 1.000 162.389 1.259 161.378 1.585 158.205 1.995 158.778 2.512 157.370 3.162 156.074 3.981 154.590 5.012 152.233 6.310 152.454 7.943 152.533 10.000 150.001 12.589 150.147 15.849 148.027 19.953 147.261 25.119 141.783 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Source: Alaskan Legend (loaded), Aware & Tanerliq Speed: 9.6 kts Source Depth: 7.5 m SL (dB re 1 µPa @ 1 m): 179.509 Frequency (kHz) SL (dB re 1 µPa @ 1 m) 0.005 170.359 0.006 167.116 0.008 169.562 0.010 164.777 0.013 155.884 0.016 156.328 0.020 151.887 0.025 157.061 0.032 151.094 0.040 156.316 0.050 162.572 0.063 159.631 0.079 155.494 0.100 161.765 0.126 154.804 0.158 158.263 0.200 155.543 0.251 155.783 0.316 160.861 0.398 163.629 0.501 160.932 0.631 170.484 0.794 173.083 1.000 170.192 1.259 163.437 1.585 163.707 1.995 154.996 2.512 154.792 3.162 153.901 3.981 152.151 5.012 151.355 6.310 151.304 7.943 147.637 10.000 148.285 12.589 148.468 15.849 147.847 19.953 147.676 25.119 142.267 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Source: Alaskan Legend (unloaded) & Tanerliq Speed: 12.6 kts Source Depth: 5.2 m SL (dB re 1 µPa @ 1 m): 185.812 Frequency (kHz) SL (dB re 1 µPa @ 1 m) 0.005 163.465 0.006 159.965 0.008 173.284 0.010 172.109 0.013 166.671 0.016 165.955 0.020 166.587 0.025 170.277 0.032 169.523 0.040 168.036 0.050 171.953 0.063 176.175 0.079 168.295 0.100 167.248 0.126 170.385 0.158 163.114 0.200 159.371 0.251 161.821 0.316 167.635 0.398 177.757 0.501 180.779 0.631 171.777 0.794 167.361 1.000 160.276 1.259 164.351 1.585 164.590 1.995 160.086 2.512 159.204 3.162 158.808 3.981 156.617 5.012 155.215 6.310 155.220 7.943 154.431 10.000 152.921 12.589 151.300 15.849 148.905 19.953 147.749 25.119 142.331

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

2011 TDR—Part II Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Northern Gateway Pipeline Project: Vessel Transit Noise

Marine Acoustics Modelling Study, 2011

Prepared for: Stantec Consulting Ltd. for Northern Gateway Pipeline Project

Prepared by: Nicole E. Chorney Andrew B. McCrodan Melanie E. Austin JASCO Applied Sciences Suite 2101, 4464 Markham St. July 19, 2012 Victoria, BC, V8Z 7X8, Canada Phone: +1.250.483.3300 P001110-002 Fax: +1.250.483.3301 Version 2.0 www.jasco.com

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Suggested citation: Chorney, N.E., A.B. McCrodan, and M.E. Austin. 2011. Northern Gateway Pipeline Project: Vessel Transit Noise, Marine Acoustics Modelling Study, 2011. Version 2.0. Technical report prepared for Stantec Consulting Ltd. for Northern Gateway Pipeline Project by JASCO Applied Sciences, January 2011.

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Acronyms and Abbreviations µPa Micropascal CPA Closest Point of Approach dB Decibels DWT Deadweight Tons GEM Gateway Environmental Management program HP Horsepower Hz Hertz kHz Kilohertz kts Knots

Glossary Audiogram A curve of hearing threshold (SPL) as a function of frequency that describes the hearing sensitivity of an animal over its normal hearing range.

Audiogram Weighting The process of applying an animal’s audiogram to sound pressure levels to determine the sound pressure levels above the animal’s hearing threshold.

Azimuth Stern Drive (ASD) Escort Tug A tug with propellers mounted on pivots that can be rotated to face any azimuthal (horizontal) direction. ASD vessels usually have better manoeuvrability than vessels with fixed propellers and rudder systems.

Bathymetric Relating to the measurements of underwater depths.

Broadband Level The sound pressure level over a specified frequency range. This is calculated by summing sound level pressures in smaller frequency bands and then converting to sound pressure th level in decibels. For example, if SPLi is the sound pressure level in the i 1/3-octave band, and ilo and ihi denote the lower and upper 1/3-octave bands in the specified frequency range respectively, then the broadband level is:

 ihi  =  SPLi 20/  BBL 10 ∑10log20   =ii lo  Ensonified Filled with sound.

Geo-acoustic Relating to the acoustic properties of the seabed. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Parabolic Equation Model A Parabolic Equation (PE) model is one that uses a parabolic solution to the acoustic wave equation, and is widely used in the acoustics community. JASCO’s MONM (Marine Operations Noise Model) is based on a version of the U.S. Naval Research Laboratory’s Range-dependent Acoustic Model (RAM), which has been modified to account for an elastic seabed. Pressure Hydrostatic pressure at any given depth in a static liquid is the result of the weight of the liquid acting on a unit area at that depth, plus any pressure acting on the surface of the liquid. Acoustic pressure is due to a deviation from the ambient hydrostatic pressure caused by a sound wave. The common symbol and units are: P [1 Pa = 106µPa = 10-5 bar].

Transmission Loss Transmission loss (TL, also referred to as propagation loss) is the dB reduction in sound level that results from the spread of sound away from an acoustic source, subject to the influence of the surrounding environment.

Sound Pressure Level The sound pressure level (SPL) is the logarithmic ratio of pressure to reference pressure [dB re 1 μPa]: SPL = ()/log20 PP 10 ref

Source Level The acoustic source level (SL) is the level referenced to a distance of 1 m from a point source. For sources that are physically larger than a few cm (ship propellers, for example), the spectrum is measured at some range, and a sound propagation model applied to compute what the spectrum would have been at 1 m range if the source could have been collapsed into a point-source. Vessel source levels are expressed in terms of pressure with units of dB re 1 μPa at 1 m.

VLCC A VLCC (Very Large Crude Carrier) is a classification of oil tanker, falling between 160,000 and 320,000 DWT in size.

Voith-Schneider Propelled (VSP) Tug A tug equipped with a Voith-Schneider propulsion system, consisting of a rotating circular array of vertical blades that protrude from the bottom of the ship. This method of Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

propulsion enables an almost instantaneous change in the direction of thrust, for excellent manoeuvrability. It also does away with the need for a rudder.

1/3-Octave Band Levels Frequency resolved pressure or energy levels in frequency bands that are 1/3 of an octave wide (where an octave is a doubling of frequency). Three adjacent 1/3-octave bands make up one octave. Fractional octave bands become wider with increasing frequency.

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Contents

1. Introduction ...... 1 2. Methods ...... 3 2.1. Propagation Loss Model ...... 3 2.2. Acoustic Source Levels ...... 4 2.3. Acoustic Environment ...... 6 2.3.1. Bathymetry ...... 6 2.3.2. Underwater sound speed...... 6 2.3.3. Seabed geoacoustics ...... 8 3. Model Scenarios and Results ...... 11 3.1. Scenario 1: Kitkiata Inlet, Tanker and 2 Escort Tugs, 9.6 kts ...... 11 3.2. Scenario 2: Principe Channel, Tanker and 2 Escort Tugs, 9.6 kts ...... 15 3.3. Scenario 3: Wright Sound, Tanker and 2 Escort Tugs, 9.6 kts ...... 18 3.4. Scenario 4: Caamaño Sound, Tanker and 2 Escort Tugs, 9.6 kts ...... 21 3.5. Scenario 5: Triple Island, Tanker and 1 Escort Tug, 16 kts ...... 24 3.6. Scenario 6: Browning Entrance, Tanker and 1 Escort Tug, 16 kts ...... 27 3.7. Scenario 7: Caamaño Sound, 1 Escort Tug, 15 kts ...... 30 4. Discussion...... 33 5. Summary ...... 34 References ...... 35 Appendix A. Audiogram-Weighted Sound Level Maps ...... 37 A.1. Scenario 1: Kitkiata Inlet, Tanker and 2 Escort Tugs, 9.6 kts ...... 39 A.2. Scenario 2: Principe Channel, Tanker and 2 Escort Tugs, 9.6 kts ...... A-43 A.3. Scenario 3: Wright Sound, Tanker and 2 Escort Tugs, 9.6 kts ...... A-47 A.4. Scenario 4: Caamaño Sound, Tanker and 2 Escort Tugs, 9.6 kts ...... A-51 A.5. Scenario 5: Triple Island, Tanker and 1 Escort Tug, 16 kts ...... A-55 A.6. Scenario 6: Browning Entrance, Tanker and 1 Escort Tug, 16 kts ...... A-59 A.7. Scenario 7: Caamaño Sound, 1 Tug, 15 kts ...... A-62

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1. Introduction This report presents the results of underwater acoustic modelling carried out by JASCO Applied Sciences to predict the extent of ensonification produced by vessel traffic transiting to and from the marine terminal near Kitimat, BC for the Northern Gateway Pipeline (NGP) Project. This study follows the 2006 Marine Acoustics Technical Data Report (Austin et al. 2006) and the 2010 Marine Acoustics Modelling Study Technical Data Report (Chorney et al. 2010), hereafter referred to as the 2006 and 2010 Modelling Studies, respectively, performed by JASCO for Jacques Whitford Ltd.1 and Stantec Consulting Ltd. (Stantec), respectively. The 2006 and 2010 Modelling Studies were based on vessel source sound levels estimated from existing measurements of similar vessel types available in the literature. The levels from the literature were adjusted to simulate a vessel travelling at ‘half-power’, corresponding to a speed of approximately 13.2 kts. The present study was conducted to incorporate more accurate source sound levels for vessels travelling at approximately 10 kts 2 following a measurement program that was conducted in July 2010 in Valdez, Alaska (MacGillivray 2010). One new scenario was modelled, and six scenarios from the 2006 and 2010 Modelling Studies were re-modelled employing vessel source levels derived from the measurements acquired in Valdez. The modelled frequency range was extended from 20 Hz–5 kHz to 20 Hz–20 kHz to include higher- frequency contributions available from the Valdez source measurements. JASCO’s Marine Operations Noise Model (MONM) was employed to predict broadband underwater sound level distributions resulting from a tanker with one or two escort tugs transiting at 16 or 9.6 kts. Sound level distributions were modelled for six scenarios, each at a unique location of interest along proposed tanker shipping routes (Figure 1). An additional scenario at Caamaño Sound was also modelled to determine sound level distributions for a solo escort tug travelling at 15 kts. The model results for each scenario are presented as maximum- over-depth sound level contour maps, and the 95% radius to the 120 dB re 1 µPa sound level threshold is given. Audiogram-weighted sound level contour maps for Orca (Orcinus orca), humpback whale (Megaptera novaeangliae), and Atlantic herring (Clupea harengus) are given in Appendix A.

1 Jacques Whitford Ltd. was purchased by Stantec in 2009. 2 Northern Gateway has committed to requiring vessel speeds of 8-10 kts in the core humpback whale area during peak periods of marine mammal abundance, and speeds of 10-12 kts in the remainder of the CCAA and for the remainder of the year. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 1. The six modelled locations along proposed tanker shipping routes. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

2. Methods 2.1. Propagation Loss Model As in the 2006 and 2010 Modelling Studies (Austin et al. 2006, Chorney et al. 2010), sound propagation at frequencies of 20 Hz to 5 kHz was modelled with JASCO’s Marine Operations Noise Model (MONM). Because the Valdez source level measurements show significant energy between 5 and 20 kHz, this frequency range was also modelled to include these higher-frequency contributions. Six scenarios were modelled at unique locations along the proposed routes for vessels calling on the Kitimat terminal (see Figure 1). The locations and sound sources for each modelled scenario are listed in Table 1. Below 5 kHz, MONM computes acoustic propagation via a wide-angle parabolic equation solution to the acoustic wave equation based on a version of the U.S. Naval Research Laboratory’s Range-dependent Acoustic Model (RAM), which has been modified to account for an elastic seabed. The parabolic equation method has been extensively benchmarked and is widely employed in the underwater acoustics community (Collins 1993). Above 5 kHz, MONM employs the widely-used BELLHOP Gaussian beam ray-trace propagation model (Porter and Liu 1995), and accounts for increased sound attenuation due to volume absorption at these higher frequencies following Fisher and Simmons (1977). MONM incorporates the following site-specific environmental properties (described in Section 2.3): a bathymetric grid of the modelling area, underwater sound speed as a function of depth, and a geoacoustic profile based on the overall stratified composition of the seafloor. For each source vessel, sound propagation loss is computed over a range of individual frequencies and is combined with the frequency-specific vessel source levels then summed over frequency to yield a grid of broadband received sound pressure levels as a function of water depth throughout the modelled area. The total received levels throughout the modelling area are the sum of the contributions from each source vessel in the scenario.

Table 1. Location, sound sources, and vessel transit speed for each modelled scenario. Transit Scenario Site Latitude Longitude Vessel sound sources speed (kts) 1 Kitkiata Inlet 53° 37.354' N 129° 12.499' W Tanker, 2 Escort tugs 9.6 2 Principe Channel 53° 22.844' N 129° 50.819' W Tanker, 2 Escort tugs 9.6 3 Wright Sound 53° 20.940' N 129° 16.560' W Tanker, 2 Escort tugs 9.6 4 Caamaño Sound 52° 53.537' N 129° 21.868' W Tanker, 2 Escort tugs 9.6 5 Triple Island 54° 18.462' N 131° 04.285' W Tanker, 1 Escort tug 16 6 Browning Entrance 53° 41.864' N 130° 40.134' W Tanker, 1 Escort tug 16 7 Caamaño Sound 52° 53.838' N 129° 21.808' W 1 Escort Tug 15

For each source vessel, underwater sound propagation was modelled at the nominal centre frequencies of consecutive 1/3-octave bands between 20 Hz and 20 kHz. At each frequency, the sound was propagated in range and depth over a fan of radial lines spanning 360º around the source, yielding a spatial grid of propagation loss values to a range of up to 40 km from the source. These propagation loss values were then applied to the corresponding 1/3-octave band source levels (described in Section 2.2) to yield received levels in each 1/3-octave band Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

throughout the modelling volume from that given source. The received levels from all acoustic sources in the model scenario were then summed to yield the total received 1/3-octave band levels throughout the modelling volume. At each point in the modelling volume, the total received 1/3-octave band levels were combined to obtain broadband (20 Hz to 20 kHz) received levels. Then, at each horizontal grid location, the maximum received sound level within the water column (i.e. maximum-over-depth) was sampled, and these samples are presented as maximum-over-depth sound level contours. This maximum-over-depth approach is more conservative than that taken in the 2006 and 2010 Modelling Studies, where broadband received levels were sampled at a standard depth of 20 m, and presents contours that define the maximum range to which an animal at any depth in the water column could be exposed to a specific sound level. For each model scenario, the 95% radius for a threshold level of 120 dB re 1 µPa was computed. This quantity is defined as the radius of the circle that contains 95% of the area ensonified above 120 dB re 1 µPa. For this study, the tanker position was used as the center about which the 95% radius was computed. The 95% radii are given for each scenario (Section 3) and consolidated in Table 7 in the Summary (Section 5). 2.2. Acoustic Source Levels Underwater noise levels were modelled using source sound levels (SLs) determined from opportunistic measurements of the 287 m (942 ft) oil tanker Alaskan Legend (loaded), the 45 m (148 ft) escort tug Tan’erliq, and the 43 m (141 ft) escort tug M/V Aware (Figure 2) transiting together at 9.6 kts in Valdez, AK (MacGillivray 2010, §3.1.3, 3.2). The Tan’erliq has a Voith- Schneider propeller (VSP), and the Aware an azimuth stern drive (ASD). These SLs are aggregate 1/3-octave band SLs of the three vessels, obtained by back-propagation from the mean source-receiver range at the CPA for the mean source depth of 6.7 m. It was not possible to measure the noise from each vessel separately (only the VSP tug was measured in isolation), and the source levels associated with each vessel measured could not be derived specifically from the aggregate level. So the SL of a single tanker or tug was calculated as described by MacGillivray (2010), assuming that each vessel contributes equally to the total source sound level and the total radiated sound power is proportional to the number of vessels:

LSʹ = LS + 10log10(Nʹ/N) = LS + 10log10(1/3) = LS – 4.77 dB (1)

where LS is the baseline 1/3-octave band source level, LSʹ is the adjusted 1/3-octave band source level, and Nʹ/N is the ratio of the number of vessels. The 1/3-octave band SLs from the Valdez measurement were each reduced by 4.77 dB to yield the 1/3-octave band SLs of a single vessel, be it tanker or tug. Third-octave band SLs were adjusted for vessel speed as described by MacGillivray (2010), based on empirical relationships given by Ross (1979, Eqs. 8.34 and 8.35) for radiated cavitation noise from surface ships, as follows:

LSʹ = LS + 60log10(vʹ/v) = LS + 60log10(16/9.6) = LS + 13.3 dB (2) where vʹ/v is the ratio of transit speeds. So the 1/3-octave band SLs of a single vessel transiting at 9.6 kts were increased by 13.3 dB to yield those of a single vessel transiting at 16 kts. Similarly, for Scenario 7, the1/3-octave band SLs were increased by 11.6 dB to yield those of a single vessel transiting at 15 kts: Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

LSʹ = LS + 60log10(vʹ/v) = LS + 60log10(15/9.6) = LS + 11.6 dB (3)

The 1/3-octave band SLs thus obtained for a single tanker or tug transiting at 9.6, 15 and 16 kts are shown in Figure 3. The source vessels in Scenarios 1 through 4 were modelled with the 9.6- kt SLs and Scenarios 5 and 6, the 16-kt SLs. The source vessel in Scenario 7 (solo escort tug) was modelled with the 15-kt SLs. All vessel sources were modelled at a source depth of 6.7 m to correspond with the mean source depth assumed in the source level calculations (MacGillivray 2010).

Table 2. Specifications of source vessels measured while transiting at 9.6 kts in Valdez, AK (MacGillivray 2010).

Vessel Class Propulsion Power (HP) Length (m) Beam (m) Draft (m) Alaskan Large Crude Carrier Fixed screw — 287 50 18.8 loaded Legend (193,000 DWT) 11.0 unloaded Tan’erliq Escort Tug Voith-Schneider 10,192 45 15 6.6 (210,500 lbs bollard pull) propeller (VSP) Aware Escort Tug Azimuth stern 10,192 43 14 4.9 (300,000 lbs bollard pull) drive (ASD)

(a) (b)

(c) Figure 2. (a) Oil tanker Alaskan Legend, (b) VSP escort tug Tan’erliq, and (c) M/V Alert, sister ship of ASD escort tug M/V Aware. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 3. Third-octave band source levels for a single tanker or tug transiting at 9.6 kts (black), 15 kts (red) and 16 kts (blue) derived from Valdez source measurements (MacGillivray 2010).

2.3. Acoustic Environment The bathymetry, sound speed profiles, and geoacoustic properties used for modelling Scenarios 1–4 are those from the 2006 Modelling Study, and those for Scenarios 5 and 6 are from the 2010 Modelling Study. Scenario 7 has the same properties as Scenario 4. 2.3.1. Bathymetry Bathymetry data for Scenarios 1–4 were provided by Jacques Whitford in 2006, based on Department of Fisheries and Oceans Canada nautical charts (Canadian Hydrographic Service 1963, 1977, 1980, 1982). The chart depth soundings were digitized by Jacques Whitford Geomatics and provided in shapefile format, Geographic datum WGS84. Bathymetry data for Scenarios 5 and 6 were obtained from the Canadian Hydrographical Service by MacGillivray (2006), consisting of ocean depth by latitude and longitude. The point bathymetry data for each scenario were converted to Universal Transverse Mercator (UTM) Zone 9N coordinates and interpolated onto a regular x–y grid for modelling. 2.3.2. Underwater sound speed Ocean sound speed profiles for Scenarios 1–4 were based on conductivity-temperature-depth (CTD) profiles provided by ASL Ltd., which were measured 2 weeks before the 2006 acoustic transmission loss (TL) field study (Austin et al. 2006). As part of the model ground-truthing of the 2006 Modelling Study, the representative sound speed profiles were adjusted to ensure that the assumed model environment generated TL estimates that agreed with the measured values at each site (Austin et al. 2006, §7.1). The resulting sound speed profiles used for modelling Scenarios 1–4 are shown in Figure 4. For Scenarios 5 and 6, underwater sound speed as a function of depth was derived for each site from temperature and salinity profiles using an empirical formula (Brekhovskikh and Lysanov 2003, Eq. 1.1.1, Chorney et al. 2010). Vertical profiles of water temperature and salinity were obtained from a catalogue of CTD profiles measured between January 1986 and February 2008 (Department of Fisheries and Oceans Canada 2008). The Dixon Entrance and Hecate Strait Subareas of the North Coast Region encompassed the Triple Island and Browning Entrance sites, Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

respectively. Profiles for autumn (Sep 1–Nov 30) conditions were used for consistency with the approach in the 2006 Modelling Study (Austin et al. 2006). Since TL measurements for these two sites were not collected during the 2006 field experiment, the data from the catalogue profiles were used directly. The resulting sound speed profiles used for modelling Scenarios 5 and 6 are shown in Figure 5. The maximum water depth within the modelling areas exceeded the range of available temperature and salinity data, so these profiles were extended to the maximum water depth (indicated in blue in each Figure). As in the 2010 Modelling Study, all profiles were extrapolated assuming a constant slope equal to that between the two deepest data points.

(a) Scenarios 1, 3 (b) Scenario 2 (c) Scenario 4 Figure 4. Sound speed profiles for modelling (a) Scenarios 1 and 3, at the Kitkiata Inlet and Wright Sound sites, respectively, (b) Scenario 2, at the Principe Channel site, and (c) Scenario 4, at the Caamaño Sound site, based on CTD casts provided by ASL that were modified following model ground-truthing (Austin et al. 2006). The extensions of the profiles beyond the range of available data are indicated in blue. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

(a) Scenario 5 (b) Scenario 6 Figure 5. Sound speed profile used for modelling (a) Scenario 5 at the Triple Island site and (b) Scenario 6 at the Browning Entrance site (Chorney et al. 2010). The extensions of the profiles beyond the range of available data are indicated in blue.

2.3.3. Seabed geoacoustics MONM assumes constant shear-wave speed and attenuation throughout the seafloor, whereas compressional-wave speed and attenuation, as well as density, can be defined to vary with depth. Tables 3–6 show the geoacoustic properties of the seafloor as a function of depth used for each model Scenario. At depths between those listed in these tables, the geoacoustic parameters are linearly interpolated between the nearest defined points. Below the lowest depth listed, the geoacoustic parameters are constant at the lowest defined values. The geoacoustic profiles for Scenarios 1–4 and 7 are based on geoacoustic parameters calculated for the given sediment types (Bornhold 1983), and the parameters were modified during model ground-truthing for the 2006 Modelling Study. The profiles for open-water Scenarios 5 and 6 were obtained from a geoacoustic database of Hecate Strait created by MacGillivray (2006) based on surficial geology maps of the Queen Charlotte Basin published by the Geological Survey of Canada (Barrie et al. 1990). The modelling sites lie within MacGillivray’s Province IV, characterized by 20 m of sand and gravel surface deposits atop bedrock (Table 6). Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Table 3. Seabed geoacoustic profile for Scenarios 1 and 2 at the Kitkiata Inlet and Principe Channel sites: density, compressional speed and attenuation, and shear speed and attenuation (Austin et al. 2006). Density Comp. Comp. atten. Shear speed Shear atten. Depth (m) Material 3 (g/cm ) speed (m/s) (dB/λ) (m/s) (dB/λ) 0 Transparent muds, 1.488 1550 0.07 glaciomarine outwash 60 1.5 1855 0.15 75 1.2 * * 90 Highly-reflective stratified 1.5 * * 105 glacial and glaciomarine 1.2 * * 120 sediments 1.5 * * 259 8.65 135 1.2 * * 150 1.5 * * 165 Non-reflective stratified 1.2 * * glacial and glaciomarine sediments ≥ 600 Bedrock 2.3 2500 0.2 * Linearly interpolated between nearest defined points.

Table 4. Seabed geoacoustic profile for Scenario 3 at the Wright Sound site: density, compressional speed and attenuation, and shear speed and attenuation (Austin et al. 2006). Density Comp. Comp. atten. Shear speed Shear atten. Depth (m) Material 3 (g/cm ) speed (m/s) (dB/λ) (m/s) (dB/λ) 0 Transparent muds, 1.388 1550 0.2 glaciomarine outwash 60 1.4 1862 0.25 75 1.5 * * 90 Highly-reflective stratified 1.4 * * 105 glacial and glaciomarine 1.5 * * 120 sediments 1.4 * * 259 8.65 135 1.5 * * 150 1.4 * * 165 Non-reflective stratified 1.5 * * glacial and glaciomarine sediments ≥ 600 Bedrock 2.3 2500 0.27 * Linearly interpolated between nearest defined points.

Table 5. Seabed geoacoustic profile for Scenario 4 at the Caamaño Sound site: density, compressional speed and attenuation, and shear speed and attenuation (Austin et al. 2006). Density Comp. Comp. atten. Shear speed Shear atten. Depth (m) Material 3 (g/cm ) speed (m/s) (dB/λ) (m/s) (dB/λ) 0 Muddy sands and muds 1.9 1550 0.009 * * ≥ 5 Bedrock 2.3 2500 * Effects of shear waves were omitted for this scenario. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Table 6. Seabed geoacoustic profile for Scenarios 5 and 6 at the Triple Island and Browning Entrance sites: density, compressional speed and attenuation, and shear speed and attenuation (Chorney et al. 2010). Depth Density Comp. Comp. atten. Shear speed Shear atten. Material 3 (m) (g/cm ) speed (m/s) (dB/λ) (m/s) (dB/λ) 0 1700.3 0.425 3 1728.6 0.432 8 Sand 1.941 1754.2 0.439 15 1770.8 0.443 70 0.90 20 1778.5 0.445 20 2200.0 Bedrock 2.200 0.100 ≥ 100 2298.4

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3. Model Scenarios and Results For each modelled scenario, the vessel layout is described. The inter-vessel distances given are the distances between the acoustic sources, located at the stern of each vessel. Two sound level contour maps, of differing scales, are presented for each modelled scenario. Sharp edges of sound level contours either indicate the boundaries of the modelled area, or are artefacts of the angular resolution of the model grid. 3.1. Scenario 1: Kitkiata Inlet, Tanker and 2 Escort Tugs, 9.6 kts A tanker transiting at 9.6 knots with leading and following escort tugs were modelled passing Kitkiata Inlet in Douglas Channel, similarly to the scenario presented in Section 7.3.3 of the 2006 Modelling Study. The vessel layout represents southward travel, with escort tugs 0.84 nmi (1550 m) forward and 0.35 nmi (640 m) off the starboard quarter of the tanker (Figure 6). The results at two different scales are shown in Figures 7 and 8. The 95% radius to a threshold level of 120 dB re 1 µPa is 3.2 km from the tanker location.

Figure 6. Relative vessel positions for Scenario 1 at the Kitkiata Inlet site: southward travel, with escort tugs 0.84 nmi (1550 m) forward and 0.35 nmi (640 m) off the starboard quarter of the tanker. Vessel sizes are exaggerated. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 7. Scenario 1. Isopleths of underwater sound levels produced by a transiting tanker and two escort tugs at the Kitkiata Inlet site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 8. Scenario 1. Larger scale view of Figure 7, showing underwater noise level isopleths for a transiting tanker and two escort tugs at the Kitkiata Inlet site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2 Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.2. Scenario 2: Principe Channel, Tanker and 2 Escort Tugs, 9.6 kts A tanker transiting at 9.6 knots with leading and following escort tugs were modelled in Principe Channel, similarly to the scenario presented in Section 7.3.5 of the 2006 Modelling Study. The vessel layout represents north-westward travel, with escort tugs 0.95 nmi (1760 m) forward and 0.4 nmi (760 m) off the starboard quarter of the tanker (Figure 9). The results at two different scales are shown in Figures 10 and 11. The 95% radius to a threshold level of 120 dB re 1 µPa is 3.5 km from the tanker location.

Figure 9. Relative vessel positions for Scenario 2 at the Principe Channel site: northwestward travel, with escort tugs 0.95 nmi (1760 m) forward and 0.4 nmi (760 m) off the starboard quarter of the tanker. Vessel sizes are exaggerated. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 10. Scenario 2. Isopleths of underwater sound levels produced by a transiting tanker and two escort tugs at the Principe Channel site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 11. Scenario 2. Larger scale view of Figure 10, showing underwater noise level isopleths for a transiting tanker and two escort tugs at the Principe Channel site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.3. Scenario 3: Wright Sound, Tanker and 2 Escort Tugs, 9.6 kts A tanker transiting at 9.6 knots with leading and following escort tugs were modelled in Wright Sound, similarly to the scenario presented in Section 7.3.4 of the 2006 Modelling Study. The vessel layout represents south-westward travel, with escort tugs 0.6 nmi (1140 m) forward and 0.26 nmi (480 m) aft of the tanker (Figure 12). The results at two different scales are shown in Figures 13 and 14. The 95% radius to a threshold level of 120 dB re 1 µPa is 1.8 km from the tanker location.

Figure 12. Relative vessel positions for Scenario 3 at the Wright Sound site: south-westward travel, with escort tugs 0.6 nmi (1140 m) forward and 0.26 nmi (480 m) aft of the tanker. Vessel sizes are exaggerated. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 13. Scenario 3. Isopleths of underwater sound levels produced by a transiting tanker and two escort tugs at the Wright Sound site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 14. Scenario 3. Larger scale view of Figure 13, showing underwater noise level isopleths for a transiting tanker and two escort tugs at the Wright Sound site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.4. Scenario 4: Caamaño Sound, Tanker and 2 Escort Tugs, 9.6 kts A tanker transiting at 9.6 knots with a leading and following escort tug were modelled in Caamaño Sound, similarly to the scenario presented in Section 7.3.6 of the 2006 Modelling Study though the 2006 model scenario included only one leading tug. The vessel layout represents westward travel, with an escort tug 0.56 nmi (1040 m) forward of the tanker and another tug 0.30 nmi (556 m) off the tanker’s stern quarter. (Figure 15). The results at two different scales are shown in Figures 16 and 17. The 95% radius to a threshold level of 120 dB re 1 µPa is 4.3 km from the tanker location.

Figure 15. Relative vessel positions for Scenario 4 at the Caamaño Sound site: westward travel, with escort tugs 0.56 nmi (1040 m) forward and 0.3 nmi (556 m) aft of the tanker. Vessel sizes are exaggerated. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 16. Scenario 4. Isopleths of underwater sound levels produced by a transiting tanker and escort tugs at the Caamaño Sound site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 17. Scenario 4. Larger scale view of Figure 16, showing underwater noise level isopleths for a transiting tanker and escort tugs at the Caamaño Sound site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.5. Scenario 5: Triple Island, Tanker and 1 Escort Tug, 16 kts A tanker transiting at 16 knots3 and a closely following escort tug were modelled at Triple Island in Dixon Entrance. The vessel layout represents westward travel, with the escort tug 0.22 nmi (400 m) off the stern quarter of the tanker (Figure 18). The results at two different scales are shown in Figures 19 and 20. The 95% radius to a threshold level of 120 dB re 1 µPa is 25.5 km from the tanker location.

Figure 18. Relative vessel positions for Scenario 5 at the Triple Island site: westward travel, with the escort tug 0.22 nmi (400 m) off the stern quarter of the tanker.

3 Northern Gateway has committed to requiring vessel speeds of 12-14 kts in the approach lanes to the CCAA for the period 1 May to 1 November; as a result, a vessel speed of 16 kts will overestimate the sound levels for this location during those times. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 19. Scenario 5. Isopleths of underwater sound levels produced by a transiting tanker and escort tug at the Triple Island site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Bathymetric contours with depths in metres are shown in grey. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 20. Scenario 5. Larger scale view of Figure 19, showing underwater noise level isopleths for a transiting tanker and escort tug at the Triple Island site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.6. Scenario 6: Browning Entrance, Tanker and 1 Escort Tug, 16 kts A tanker transiting at 16 knots4 and a closely following escort tug were modelled at Browning Entrance in Hecate Strait. The vessel layout represents north-westward travel (bearing 320°), with the escort tug 0.22 nmi (400 m) off the stern quarter of the tanker (Figure 21). The results at two different scales are shown in Figures 22 and 23. The 95% radius to a threshold level of 120 dB re 1 µPa is 22.7 km from the tanker location.

Figure 21. Relative vessel positions for Scenario 4 at the Browning Entrance site: north-westward travel (bearing 320°), with the escort tug 0.22 nmi (400 m) off the stern quarter of the tanker.

4 Northern Gateway has committed to requiring vessel speeds of 12-14 kts in the approach lanes to the CCAA for the period 1 May to 1 November; as a result, a vessel speed of 16 kts will overestimate the sound levels for this location during those times. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 22. Scenario 6. Isopleths of underwater sound levels produced by a transiting tanker and escort tug at the Browning Entrance site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Bathymetric contours with depths in metres are shown in grey. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 23. Scenario 6. Larger scale view of Figure 22, showing underwater noise level isopleths for a transiting tanker and escort tug at the Browning Entrance site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

3.7. Scenario 7: Caamaño Sound, 1 Escort Tug, 15 kts An escort tug transiting at 15 knots was modelled in Caamaño Sound, similar to the scenario presented in Section 7.3.6 of the 2006 Modelling Study, but with only the one vessel (Figure 24). The results at two different scales are shown in Figures 25 and 26. The 95% radius to a threshold level of 120 dB re 1 µPa is 13.3 km from the escort tug location.

Figure 24. Vessel position for Scenario 7 at the Caamaño Sound site: westward travel, with one tug travelling at 15 kts. Vessel sizes are exaggerated. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 25. Scenario 7. Isopleths of underwater sound levels produced by a transiting tug at the Caamaño Sound site. Levels are maximum-over-depth, unweighted, broadband (20 Hz – 20 kHz) sound pressure in decibels referenced to 1 μPa. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

Figure 26. Scenario 7. Larger scale view of Figure 25, showing underwater noise level isopleths for a transiting tug at the Caamaño Sound site. Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

4. Discussion In this report, one new scenario and six scenarios from the 2006 and 2010 Modelling Studies were revisited using the updated source level data from the opportunistic Valdez measurement (MacGillivray, 2010); specifically, a measurement of the combined noise from the oil tanker Alaskan Legend, the VSP escort tug Tan’erliq, and the ASD escort tug M/V Aware. Sound levels were modelled based on vessels speeds of 9.6 kts in the four scenarios for the CCAA, 16 kts in two scenarios for the OWA, and 15 kts for solo escort tug transit in the CCAA. It was necessary to divide the combined Valdez measurement among each vessel to model the spread of spatially separated vessels as individual sources. It was important to retain the geometry of the vessel convoy, rather than model them as a single combined source, to properly estimate the extent of ensonification, particularly in the confined channel scenarios. This approach also provided contour maps visually comparable with those in the previous reports. At long range, the distance separating each vessel becomes less significant and the result is the same as that for a combined source. It was not possible to partition the composite level by vessel type, so it was assumed that each vessel contributed equally to the total measured sound level (see §2.2). While it is unlikely that this is the case, this is believed to be a reasonable estimation and using this approach each vessel in the convoy contributes to the overall spread of sound. In reality it could be expected that the tugs would dominate the noise from the tanker. If that were the case, the combined source level from the Valdez measurement would then be better divided among two sources (the two tugs) rather than three. This means that the approach used in generating the results presented in this report could slightly overestimate (by 0.5 dB) the source level for the scenarios in the OWA with only one tug and a tanker. For the same reason, the source level of the single tug in Scenario 7 may be slightly underestimated. It is noted that the vessels measured in the Valdez study are not the same vessels that will travel to and from the planned marine terminal, and as such may have different broadband source levels and frequency distributions. The 193,000-DWT Alaskan Legend, classified as a VLCC, is at the low end of its spectrum, as this category extends to 320,000 DWT. Also, as described in the Valdez report, the source level back-propagation contained possible sources of error. Using the mean position and source depth of the three vessels when estimating the overall source level could have introduced an error of ±2 dB, and assuming the seabed sediments to be “silty-sand” was an intermediate case between “silt” and “rock” that could also have introduced an error of ±3 dB in the source level estimation. Discussion in the Valdez report (MacGillivray 2010, §4) illustrated that vessel speed was responsible for the main difference between the surrogate source levels used in the 2006 Modelling Study and those based on the Valdez measurements. At a transit speed of 9.6 kts, the source levels derived from the Valdez measurement were 7-20 dB lower in most frequency bands compared to the surrogate levels at 13.2 kts used in the 2006 study for the confined channel scenarios. At the increased vessel speed of 16 kts for the open water scenarios, the source levels from the Valdez measurement exhibited levels that were 3-5 dB higher for frequencies above 300 Hz compared to the surrogate levels at 13.2 kts used for the 2010 Modelling Study. These differences are reflected in the results of this report: compared to the 2006 and 2010 Modelling Studies, same-valued contours at 9.6 kts in the confined channels were found to have smaller extent, and those at 16 kts in the open water extended further. Comparing Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

the results of Scenarios 4 and 7 also underline the effect of vessel speed on sound level. Equations 1 and 3 show that, under the approach taken for this modelling, reducing the number of vessels from three to one reduces the SL by 4.77 dB, whereas changing the speed to 15 kts from 9.6 kts increases the SL by 11.6 dB. The result was a 9-km increase in the 95th percentile 120 dB re 1 µPa radius.

5. Summary This report presents underwater sound levels expected from transiting tanker and escort tugs associated with NGP’s marine terminal near Kitimat, BC, as predicted by JASCO’s proprietary MONM underwater acoustic propagation model. Sound propagation was modelled in 1/3-octave frequency bands from 20 Hz to 20 kHz and the maximum received sound level within the water column was sampled. Broadband received sound levels were determined by summing the maximum-over-depth 1/3-octave band levels and are presented as isopleth contours over each modelled area. Six scenarios were modelled at unique sites along proposed vessel transit routes: four sheltered sites in Kitkiata Inlet, Principe Channel, Wright Sound, and Caamaño Sound, and two open- water sites at Triple Island in Dixon Entrance, and Browning Entrance in Hecate Strait. The sheltered scenarios consisted of a tanker transiting at 9.6 kts with two escort tugs, and the open- water scenarios consisted of a tanker transiting at 16 kts with one escort tug. A new scenario for this study considered a solo escort tug transiting through Caamaño Sound at 15 kts. Acoustic source levels were derived from measurements of the 287 ft oil tanker Alaskan Legend, the 45 ft VSP escort tug Tan’erliq, and the 43 ft ASD escort tug M/V Aware transiting together at 9.6 kts in Valdez, AK (MacGillivray 2010). Underwater sound level maps for each scenario are presented in Section 3. Table 7 below lists the 95% radius to a threshold level of 120 dB re 1 µPa (radius of circle containing 95% of the area ensonified above 120 dB re 1 µPa) for each model scenario. The 1.8 km radius for the Wright Sound scenario is smaller than the other sheltered site scenarios primarily due to decreased tug/tanker distance. This result highlights the possibly mitigating effects of keeping the vessels close together.

Table 7. 95% radius to a received sound level threshold of 120 dB re 1 µPa for each model scenario. Transit 95% radius (km) Scenario Site Vessel sound sources speed (kts) to 120 dB re 1 µPa 1 Kitkiata Inlet Tanker, 2 Escort tugs 9.6 3.2 2 Principe Channel Tanker, 2 Escort tugs 9.6 3.5 3 Wright Sound Tanker, 2 Escort tugs 9.6 1.8 4 Caamaño Sound Tanker, 2 Escort tugs 9.6 4.3 5 Triple Island Tanker, 1 Escort tug 16 25.5 6 Browning Entrance Tanker, 1 Escort tug 16 22.7 7 Caamaño Sound 1 Escort tug 15 13.3

Attachment 15 to Northern Gateway Reply Evidence Part 1 of 2

References

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Johnson, C.S. 1967. Sound detection thresholds in marine mammals. Pages 247-260 in W.N. Tavolga, (ed.) Marine Bio-Acoustics, Vol. 2. Pergamon Press, Oxford, UK. Cited in: Erbe. C. 2001. Underwater Noise of Whale- Watching Boats and Potential Effects on Killer Whales (Orcinus Orca), Based on an Acoustic Impact Model. Report for Fisheries and Oceans Canada. MacGillivray, A.O. 2006. An Acoustic Modelling Study of Seismic Airgun Noise in Queen Charlotte Basin. M.Sc. Thesis, University of Victoria, 98 p. MacGillivray, A. 2010. Northern Gateway Pipeline Project: Management Tanker and Escort Tug Source Level Measurement Study, Valdez Alaska, 2010. Technical report prepared for Stantec Consulting Ltd. for Northern Gateway Pipeline Project by JASCO Applied Sciences, November 2010. Porter, M. and Y.C. Liu. 1995. Finite-element ray tracing. Proc. Int. Conf. on Theoretical Comp. Acoust. Theoretical Comp. Acoust. 2:947-956. Szymanski, M.D., D.E. Bain, K. Kiehl, S.Pennington, S. Wong, and K.R. Henry. 1999. Killer whale (Orcinus orca) hearing: Auditory brainstem response and behavioral audiograms. Journal of the Acoustical Society of America 106:1134-1141. Cited in: Erbe. C. 2001. Underwater Noise of Whale-Watching Boats and Potential Effects on Killer Whales (Orcinus Orca), Based on an Acoustic Impact Model. Report for Fisheries and Oceans Canada. Tremel, D.P., J.A. Thomas, K.T. Ramirez, G.S. Dye, W.A. Bachman, A.N. Orban, and K.K. Grimm. 1998. Underwater hearing sensitivity of a Pacific white-sided dolphin, Lagenorhynchus obliquidens. Aquatic Mammals 24:63-69. Cited in: Erbe. C. 2001. Underwater Noise of Whale-Watching Boats and Potential Effects on Killer Whales (Orcinus Orca), Based on an Acoustic Impact Model. Report for Fisheries and Oceans Canada.

Attachment 15 to Northern Gateway Reply Evidence Part 2 of 2 JASCO Applied Sciences GEM: Marine Acoustics Study, 2011

Appendix A. Audiogram-Weighted Sound Level Maps The sound level distributions modelled for each scenario were audiogram weighted as in the 2006 Modelling Study, but extended in frequency up to 20 kHz. Broadband noise levels were weighted based on audiograms from the literature. That for Orca (Orcinus orca, Erbe 2001) is the mean of audiograms of several odontocetes (Johnson 1967, Hall and Johnson 1972, Szymanski et al. 1999, review by Erbe and Farmer 1998, Tremel et al. 1998). Those for humpback whale (Megaptera novaeangliae, Erbe 2002) are the relative audiogram predicted by Houser et al. (2001) positioned on the y-axis assuming minimum thresholds at the frequency of best hearing of 40 and 70 dB re 1µPa. That for Atlantic herring (Clupea harengus) is the audiogram resulting from measurements of neurophysiological responses by Enger (1967). The hearing threshold at the central frequency of each 1/3-octave band was linearly interpolated from these data (Figure A-1). The audiograms were extended to lower frequencies by linear extrapolation, and extended conservatively to higher frequencies by assuming the highest frequency value to be constant thereafter. For each species, the 1/3-octave band hearing thresholds were subtracted from the corresponding modelled 1/3-octave band noise levels (maximized over depth in the water column), and the resulting weighted 1/3-octave band levels were summed to yield broadband noise levels above the hearing threshold. Presented here are the audiogram-weighted sound level contour maps for each model scenario (Section 3) for Orca, humpback whale, and Atlantic herring. The near-field contours in the audiogram threshold maps for Orca and humpback whales are strongly influenced by the inclusion of frequencies from 5 kHz – 20 kHz since the hearing thresholds for those species are very low at these high frequencies. The frequency distribution of the vessel source levels also influences the spatial extent of the audiogram-weighted contour maps. The modelled vessel source levels exhibit a strong peak at 800 Hz and significant sound energy above 1 kHz, frequencies at which orca and humpbacks have low hearing thresholds.

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Figure A-1. Audiograms for Orca (Orcinus orca), humpback whale (Megaptera novaeangliae), and Atlantic herring (Clupea harengus) from the literature and the values applied for audiogram weighting of model results.

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A.1. Scenario 1: Kitkiata Inlet, Tanker and 2 Escort Tugs, 9.6 kts A.1.1. Orca

Figure A-2. Scenario 1. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Kitkiata Inlet site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.1.2. Humpback whale

Figure A-3. Scenario 1. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Kitkiata Inlet site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.1.3. Atlantic herring

Figure A-4. Scenario 1. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Kitkiata Inlet site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.2. Scenario 2: Principe Channel, Tanker and 2 Escort Tugs, 9.6 kts A.2.1. Orca

Figure A-5. Scenario 2. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Principe Channel site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.2.2. Humpback whale

Figure A-6. Scenario 2. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Principe Channel site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.2.3. Atlantic herring

Figure A-7. Scenario 2. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Principe Channel site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.3. Scenario 3: Wright Sound, Tanker and 2 Escort Tugs, 9.6 kts A.3.1. Orca

Figure A-8. Scenario 3. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Wright Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels

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A.3.2. Humpback whale

Figure A-9. Scenario 3. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Wright Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.3.3. Atlantic herring

Figure A-10. Scenario 3. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Wright Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.4. Scenario 4: Caamaño Sound, Tanker and 2 Escort Tugs, 9.6 kts A.4.1. Orca

Figure A-11. Scenario 4. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Caamaño Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.4.2. Humpback whale

Figure A-12. Scenario 4. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Caamaño Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.4.3. Atlantic herring

Figure A-13. Scenario 4. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Caamaño Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.5. Scenario 5: Triple Island, Tanker and 1 Escort Tug, 16 kts A.5.1. Orca

Figure A-14. Scenario 5. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Triple Island site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.5.2. Humpback whale

Figure A-15. Scenario 5. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Triple Island site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.5.3. Atlantic herring

Figure A-16. Scenario 5. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Triple Island site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.6. Scenario 6: Browning Entrance, Tanker and 1 Escort Tug, 16 kts A.6.1. Orca

Figure A-17. Scenario 6. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting tanker and two escort tugs at the Browning Entrance site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.6.2. Humpback whale

Figure A-18. Scenario 6. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tanker and two escort tugs at the Browning Entrance site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.6.3. Atlantic herring

Figure A-19. Scenario 6. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tanker and two escort tugs at the Browning Entrance site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.7. Scenario 7: Caamaño Sound, 1 Tug, 15 kts A.7.1. Orca

Figure A-20. Scenario 7. Isopleths of underwater sound levels above the hearing threshold of orca (Orcinus orca) produced by a transiting 7 tug at the Caamaño Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.7.2. Humpback whale

Figure A-21. Scenario 7. Isopleths of underwater sound levels above the hearing threshold of humpback whale (Megaptera novaeangliae) produced by a transiting tug at the Caamaño Sound site. Levels are maximum-over- depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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A.7.3. Atlantic herring

Figure A-22. Scenario 7. Isopleths of underwater sound levels above the hearing threshold of Atlantic herring (Clupea harengus) produced by a transiting tug at the Caamaño Sound site. Levels are maximum-over-depth, weighted, broadband (20 Hz – 20 kHz) sound pressure in decibels.

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2012 Marine Acoustic Supplement Reply Evidence Section 3: Killer Whale-Specific Hearing Threshold Weighting Methodology

3 Killer Whale-Specific Hearing Threshold Weighting Methodology

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Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales

Submitted to: Stantec Consulting Ltd. for Northern Gateway Pipeline Project

Prepared by Alexander MacGillivray Graham Warner David Hannay JASCO Applied Sciences Suite 202, 32 Troop Ave. 18 July 2012 Dartmouth, NS B3B 1Z1 Canada Phone: +1-902-405-3336 P001142-001 Fax: +1-902-405-3337 Version 3.0 www.jasco.com

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JASCO APPLIED SCIENCES Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales

Suggested citation: MacGillivray, A., G. Warner, and D. Hannay. 2012.Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales. Version 3.0. Technical memorandum by JASCO Applied Sciences for Stantec Consulting Ltd. for Northern Gateway Pipeline Project.

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JASCO APPLIED SCIENCES Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales

Contents

1. OVERVIEW ...... 1 2. ANALYSIS METHODS ...... 1 LITERATURE CITED ...... 3

Figures Figure 1. Killer whale audiogram (green) overlaid on top of estimated 1/3-octave band received sound levels for a 5.2 m inflatable whale watching boat. Red line shows sound levels at 200 m for fast-speed approach (116 dB re 1 µPa broadband SPL) and blue line shows sound levels at 100 m for slow-speed approach (108 dB re 1 µPa broadband SPL). Dotted lines indicate extrapolated levels above 24 kHz...... 2

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JASCO APPLIED SCIENCES Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales

1. Overview JASCO reviewed the scientific literature to find documented evidence of disturbances to northern resident killer whales (NRKWs) by marine vessels. Two studies documented behavioural disturbances to NRKWs due to vessels and estimated received sound levels believed to cause those disturbance reactions: • Williams et al. (2002a) performed an experiment that measured NRKWs’ behavioural responses to leapfrogging1 whale watching boats. NRKWs overtly avoided erratically- moving, fast-approaching whale watching boats at approximately 200 m range. The investigators measured the source level of the boat and estimated that sound levels received by the NRKWs were 116 dB re 1 µPa. • Williams et al. (2002b) performed an experiment that measured NRKWs’ behavioural responses to a whale watching boat moving slowly and approaching parallel to the whales at 100 m, a voluntary code of conduct. NRKWs exhibited subtle, but statistically significant, avoidance responses to a whale watching boat under these conditions. Received sound levels were not reported in this paper, but one of the study’s authors confirmed that the NRKWs exhibited subtle responses at estimated sound levels of 108 dB re 1 µPa (R. Williams, pers. comm.). In the current study, JASCO weighted the reported sound levels according to the mean killer whale audiogram (Erbe 2002) to estimate the level above hearing threshold2. Based on information from Williams et al. (2002a, b) on behavioural responses of NRKW to whale watching vessels, JASCO determined that at received sound levels of approximately 64 dB above their hearing threshold killer whales overtly avoided a whale watching boat, whereas they subtly avoided a whale watching boat at received sound levels of approximately 57 dB above their hearing threshold.

2. Analysis Methods JASCO computed audiogram-weighted sound levels for the whale watching boat by deriving 1/3-octave band sound levels based on data presented in Fig. 4 of Williams et al. (2002a). Sound levels were measured at 100 m range for a 5.2 m rigid-hull Zodiac inflatable boat transiting at 20.7 km/h (fast) and 5.2 km/h (slow) speed. JASCO scaled the 1/3-octave band sound levels so they summed to the 116 dB re 1 µPa and 108 dB re 1 µPa stimulus levels reported by the investigators. The maximum frequency of the acoustic measurements was 24 kHz, so to compare with a killer whale audiogram, JASCO extrapolated the levels to 100 kHz by assuming the sound level in the bands above 24 kHz were equivalent to those in the 24 kHz band. Figure 1 shows the resulting sound levels alongside a

1 Leapfrogging is the practice of of speeding up a boat to place it in the path of a pod of whales. 2 The mean killer whale audiogram is a composite hearing threshold that is not specific to any particular population. JASCO expects that hearing ability and behavioural responses would be comparable across different groups of killer whales (northern resident, southern resident, transient).

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killer whale audiogram. To calculate the noise level above the hearing threshold for killer whales, JASCO weighted the sound levels according to the audiogram and summed these over the 1/3-octave bands. JASCO found that the audiogram-weighted noise levels for killer whales were 64 dB above hearing threshold for overt avoidance and 57 dB above hearing threshold for subtle avoidance.

Figure 1. Killer whale audiogram (green) overlaid on top of estimated 1/3-octave band received sound levels for a 5.2 m inflatable whale watching boat. Red line shows sound levels at 200 m for fast-speed approach (116 dB re 1 µPa broadband SPL) and blue line shows sound levels at 100 m for slow-speed approach (108 dB re 1 µPa broadband SPL). Dotted lines indicate extrapolated levels above 24 kHz.

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JASCO APPLIED SCIENCES Northern Gateway Pipeline Project: Audiogram-Weighted Behavioural Thresholds for Killer Whales

Literature Cited

Erbe, C. 2002. Underwater noise of whale-watching boats and potential effects on killer whales (Orcinus orca), based on an acoustic impact model. Marine Mammal Science 18(2):394-418. Holt, M.M. 2008. Sound exposure and Southern Resident killer whales (Orcinus orca): A review of current knowledge and data gaps. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-89, 59 p. Williams, R., D. E. Bain, J. K. B. Ford and A. W. Trites. 2002a. Behavioural responses of male killer whales to a ‘leapfrogging’ vessel. Journal of Cetacean Research and Management 4(3):305-310. Williams, R., A. W. Trites, and D. E. Bain. 2002b. Behavioural responses of killer whales (Orcinus orca) to whale- watching boats: opportunistic observations and experimental approaches. Journal of Zoology, London 256: 255-270. Williams, R.. 2012. Marie Curie Research Fellow at the Sea Mammal Research Unit (SMRU), University of St Andrews, Scotland, by email, June 21, 2012.

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2012 Marine Acoustic Supplement Reply Evidence Section 4: Summary of Underwater Acoustic Studies and Implications for the May 2010 Application’s Assessment and Conclusions

4 Summary of Underwater Acoustic Studies and Implications for the May 2010 Application’s Assessment and Conclusions The following section presents:

1. A brief background on the objectives of the 2006, 2006, and 2011 acoustic modelling study TDRs 2. A high-level summary of the Application’s conclusions, based on the 2006 and 2010 TDRs 3. An interpretation of how the updated technical findings from 2011 may have altered any conclusions drawn in the Application.

4.1 Background on the 2006, 2010, and 2011 Acoustic Modelling Study Technical Data Reports JASCO was engaged by Northern Gateway to conduct two separate underwater acoustic modelling studies (Marine Acoustics (2006) Technical Data Report and Marine Acoustics Modelling Study 2010 Technical Data Report) to inform the assessment of potential environmental effects resulting from Project-related vessel underwater noise. These studies, which are available on the NEB website, were used during development of the May 2010 Application and are summarized briefly below.

1 4.1.1 Marine Acoustics (2006) Technical Data Report One of the primary goals of this report was “To predict the extent of underwater ensonification produced by marine vessels involved in the operation of the marine terminal and for the shipping of crude and condensate”. To this end, acoustic modelling was carried out to generate maps showing the underwater sound level distributions for a set of six scenarios representing Project operations in the Confined Channel Assessment Area (CCAA) and one associated with construction of the marine terminal (i.e., clamshell dredging): 1. berthing at the marine terminal (tanker plus two harbour and two escort tugs) 2. standby at the marine terminal (tanker) 3. transit past Kitkiata Inlet in Douglas Channel (tanker plus two escort tugs) 4. transit through Principe Channel (tanker plus two escort tugs) 5. transit through an Wright Sound (tanker plus three escort tugs – an early operational scenario which has since been modified )2

1 Austin et al. 2006; Parts 1 through 9 – NEB Reference Numbers: A1V5S9, A1V5T0, A1V5T1, A1V5T2, A1V5T3, A1V5T4, A1V5T5, A1V5T6, and A1V5T7 2 As noted in the May 2010 Application, since the time of initial modelling in 2006, Northern Gateway has committed to having all laden tankers accompanied by two escort tugs (one close and one tethered) throughout the CCAA. Please see Section 4.1.3 (below) for details on the 2011 update to these scenarios.

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6. transit through Caamaño Sound (tanker plus one escort tug – an early operational scenario which has since been modified)3 7. dredging at the marine terminal (clamshell dredge) Source levels used for the model predictions were obtained from a literature review of vessel measurements and were then calibrated to better suit the scenarios3. Additional analyses were done that applied audiogram4-weighting to the modelled broadband noise levels, resulting in maps that displayed only sound levels above the hearing threshold of the selected species (i.e., herring, salmon, flatfish, humpback whale, killer whale, and Steller sea lion).

5 4.1.2 Marine Acoustics Modelling Study 2010 Technical Data Report This report used the same acoustic model and the same source levels6 that were used in the 2006 TDR, only at four locations along proposed vessel transit routes in the open water area (OWA): 1. transit near7 Langara Island in Dixon Entrance (tanker) 2. transit near Cape St. James in the Queen Charlotte Basin (tanker) 3. transit near Triple Islands in Dixon Entrance (tanker plus one escort tug) 4. transit near Browning Entrance in Hecate Strait (tanker plus one escort tug) The model results were presented in a similar fashion to the 2006 TDR; however, the report did not include audiogram weighting. Only scenarios 3 and 4 were considered in detail in the May 2010 Application.

4.1.3 Marine Acoustics 2011 Technical Data Report (Section 2 of this Supplement) The 2006 and 2010 TDRs were based on vessel source sound levels estimated from existing measurements available in the literature. The 2011 TDR (Section 2 of this supplement) was conducted to incorporate more accurate sound source levels from an in-field measurement program that was conducted in July 2010 at Valdez, Alaska8. The 2011 TDR used these updated source levels to re-model six of the scenarios from the 2006 and 2010 TDRs along proposed vessel transit routes: four in the CCAA (Kitkiata Inlet, Principe Channel, Wright Sound, and Caamaño Sound) and two in the OWA (Triple Island and Browning Entrance). As in the 2006

3 See Section 4.3.1 for a discussion of the tanker source levels used in the 2006 modelling 4 An audiogram is the species-specific curve of hearing threshold versus frequency. When broadband noise levels are weighted against audiograms, the resulting sound levels are in units of “dB re threshold”. Sound levels less than 0 dB re threshold are below the audible limit for a particular species and are therefore expected to be inaudible. 5 Chorney et al. 2010; Part 1 of 1 – NEB Reference Number: A1V5T8 6 See Section 4.3 for a discussion of the tanker source levels used in the 2006 and 2010 modelling 7 The term ‘near’ in these scenarios is used to mean ‘within 25 nautical miles of’. 8 The method behind this acoustic field study is presented in MacGillivray 2010 (see Section 2, Part I of this supplement). Re-modelling of the scenarios using these updated source levels is presented in Chorney et al. 2011 (see Section 2, Part II of this supplement).

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TDR, modelled sound level distributions for each scenario are audiogram weighted, but in this case are extended in frequency up to 20 kHz. Furthermore, acoustic modelling conducted in 2006 simulated one to three escort tugs for various locations in the CCAA (see Section 4.1.1 above for the list of scenarios). Since then, Northern Gateway has committed to the following: • All laden tankers will have a close escort tug between the pilot boarding stations at Triple Islands, Browning Entrance and Caamaño Sound and the Kitimat Terminal. In addition, all laden tankers will have a tethered escort tug between proposed pilot stations at Browning Entrance or Caamaño Sound and the Kitimat Terminal (i.e., throughout the CCAA). • All tankers in ballast will have a close escort tug between the pilot boarding stations at Triple Islands, Browning Entrance or Caamaño Sound and the Kitimat Terminal. The four 2011 TDR modelling scenarios in the CCAA are corrected to incorporate these operational scenarios and provide a more accurate simulation of underwater noise expected by vessels associated with the Project (i.e., acoustic scenarios in the CCAA are modelled using one tanker with two escort tugs). An additional scenario in Caamaño Sound was also modelled to determine sound level distributions for a solo escort tug travelling at 15 knots.

4.2 Conclusions Presented in the May 2010 Application The May 2010 Application identified “behavioural changes due to underwater noise” as a key environmental effect for marine mammals (Volume 8B, Table 10-2). This key effect was assessed for all marine mammals in the CCAA, using northern resident (NR) killer whale as the representative toothed whale, North Pacific (NP) humpback whale as the representative baleen whale, and Steller sea lion as the representative pinniped. In the OWA, baleen whales (in general) were used to assess the effects of behavioural change due to underwater noise. The May 2010 Application concluded that “the residual effect of behavioural change due to underwater noise is not expected to affect the long-term viability of a pod of NR killer whales or their entire population”. This assessment result was based on mitigation measures and the fact that a large component of the sound energy produced by Project-related vessels will not be heard by NR killer whales, given their species-specific hearing threshold (see Section 3 of this supplement for details on this threshold). The May 2010 Application concluded that although conservative assumptions were used in the assessment, the NR killer whale population is small, threatened, and potentially limited by availability of prey. Furthermore, overall confidence in the assessment for the environmental effect of behavioural change due to underwater noise was rated as low. The basis of this prediction was related to the unconfirmed efficacy of proposed mitigation measures and to the lack of available baseline data and poor scientific understanding on factors such as potential long-term effects (e.g., subtle behavioural changes and communication masking) relating to chronic anthropogenic underwater noise. Given that the CCAA includes potential critical habitat for the NR killer whale and that, among other things, the amount of important foraging habitat for this species in the CCAA is not known, a confident determination of significance for both residual and cumulative effects was deemed not currently possible. For NP humpback whales, it was determined that although underwater sound from vessels may affect the behaviour and habitat use of individual humpback whales in the CCAA, it will not affect the viability of

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the broader NP humpback whale population (given its large size and increasing trend), or delay the continuing recovery of the Canadian portion of this population. Therefore, both the residual and cumulative effects were concluded to be not significant. It is noted here, that since the initial writing of the May 2010 Application, the NP humpback whale population has been down-listed from Threatened to Special Concern (COSEWIC 2011). Assessment of the effects of marine transportation in the OWA further determined that behavioural change due to underwater noise was not expected to affect the long-term viability of any population of baleen whale in the OWA, and both residual and cumulative effects were determined to be not significant. Among a variety of mitigation measures to minimize potential behavioural changes, Northern Gateway committed to incorporating the best commercially available technology at the time of tug design and construction, so that escort and harbour tugs produce the least underwater noise possible. Examples of this technology included potential use of Voith-Schneider propulsion (VSP) technology (see also Section 4.4.1 below) and/or modified Azimuth Stern Drive (ASD) propulsion systems. Reduced vessel speeds are also expected to help reduce the effects of underwater noise on marine mammals.

4.3 Implications for the May 2010 Application’s Conclusions

4.3.1 Factors Influencing the Conclusions

Tanker Source Levels A VLCC is a classification of oil tanker with a size between 160,000 and 320,000 DWT. At the time of the 2006 and 2010 TDRs, sound source levels were unavailable for a VLCC. Instead, the source levels used for the ‘VLCC tanker’ in the 2006 TDR were based on published measurements of a 'generic tanker' of length 240 m and of unspecified power, travelling under full power at 16 knots (Malme et al. 1989). To be more representative of VLCC operations in the CCAA, the reported levels were decreased by 5 dB in the 2006 TDR to approximate a 'half power' setting, corresponding to a speed of approximately 13.2 knots9. Source levels used in the 2010 TDR were from the same vessel surrogates but the 5 dB ‘half power’ reduction was not applied, to better represent transit in open water at full sea speed (16 knots)10.

9 Northern Gateway has committed to requiring tanker and tug speeds of 8-10 knots in the core humpback whale area for the period 1 May to 1 November. The spatial and temporal boundaries of the core humpback whale area will be refined from data collected through marine mammal density surveys and the quantitative vessel strike analysis. Throughout the remainder of the year in the core humpback whale area, and year-round in the CCAA outside of the core humpback whale area, tankers and accompanying escort tugs will travel at a maximum speed of 10 to 12 knots. Unaccompanied tugs may transit the CCAA at speeds of up to 15 knots, except while in the core humpback whale area during 1 May to 1 November, as described above. 10 In the “CCAA approaches”, Northern Gateway will require tanker speeds to be less than 14 knots for the period 1 May to 1 November. Surveying of seasonal whale densities and distributions will be used to better define this period, and the quantitative vessel strike analysis will be used to better define the geographical extent of this area. Otherwise, vessel speeds in the OWA will generally be in the range of 14 to 16 knots. The term “CCAA approaches” is used here to replace the term “approach lanes”, which was used in the May 2010 Application (see Application, Volume 8B, Section 2.4.1).

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In 2011, the results were updated using more appropriate field-measured sound levels for a larger oil tanker. A comparison of tanker specifications by vessel class is presented in Table 4-1 for the predicted Project-related vessel traffic and the modelled values. The 2011 TDR applied measurements of the 287 m, 193,000-DWT oil tanker Alaskan Legend, the largest tanker available for measure. Although it is classified as a VLCC, it is at the low end of the size spectrum (Section 2, Part I of this supplement). The Alaskan Legend is smaller than the VLCCs proposed for use by Northern Gateway and thus closer to the maximum size of a Suezmax. Consequently, the 2011 TDR likely underestimates sound levels produced from larger VLCCs (approximately 23% of expected tanker traffic), but overestimates sound levels from Aframax (approximately 23% of expected tanker traffic) and is reasonably representative of Suezmax (approximately 55% of expected tanker traffic). Section 4.3.2 and 4.3.3 present a discussion of how the 2011 TDR (which also factors in sound produced by escort tugs) will influence the May 2010 Application’s conclusions in the CCAA and OWA, respectively (see also Table 4-2).

Table 4-1 Comparison of Predicted Tanker Specifications

Estimates of Project-related Tanker Traffic Values used in Acoustic Models VLCC Suezmax Aframax (design (average (design 2006 Tanker 2011 Tanker Parameter maximum) values) minimum) Surrogate Measurement Overall length (m) 344 274 221 240 287 Maximum dwt 320,472 160,000 81,408 unknown 193,000 Number of vessels per 40 to 60 110 to 130 40 to 60 220 220 year (range) Number of vessels per 50 120 50 220 220 year (average) Approximate % of 23% 55% 23% 100% 100% expected tanker traffic annually

Voith-Schneider Propulsion (VSP) Technology Acoustic modelling in the 2006 TDR used the underwater sound signatures of traditional (screw propeller) tugs. The primary objective of the 2010 study in Valdez, Alaska (Section 2, Part 1 of this supplement) was to understand the acoustic benefit of VSP technology. Measurements of the VSP escort tug at Valdez did not indicate significant noise savings in comparison to conventional propulsion, except possibly at infrasound frequencies (i.e., below 40 Hz). Regardless, Northern Gateway remains committed to remaining up-to-date on advancements in the field and to incorporating the best noise quieting technology at the time of tug design and construction.

Projection Error Identified in 2006 TDR A projection error in JASCO’s mapping software was identified during the preparation of the 2011 TDR, whereby the scale bar and measurement tool from the GIS package provided incorrect measurements. Consequently, the scale bars on all maps presented in the 2006 TDR show incorrect values and ranges to the distal edge of the 120 dB quoted in the 2006 TDR (derived from the erroneous measurement tool) are too large. As a result, figures and numerical calculations in the May 2010 Application which relate to the

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extent of underwater ensonification and duration of exposure in the CCAA are also incorrect11. As the projection error over-estimates the spatial extent of underwater sound in the CCAA capable of invoking a behavioural response, conclusions made in the May 2010 Application based on these values are considered conservative. A summary of how predicted areas of behavioural change are affected by this error is presented in Table 4-2. The range to the edge of the 120 dB contour was more accurately computed for the 2010 and 2011 TDRs (i.e., ranges were calculated directly from the output of the acoustic model using JASCO’s post- processing software rather than using a GIS measurement tools). Therefore, this projection error does not affect any of the OWA model scenarios and is corrected for in the CCAA scenarios presented in the 2011 TDR.

Table 4-2 Summary of Changes to Estimated Area of Behavioural Change Based on 120 dB Contour, Calculated in the 2006, 2010, and 2011 TDRs

CCAA Scenarios Source Levels Surrogate—from Literature In-field measurements—Valdez 120 dB contour 95% radius Range to edge of 120 dB contour (computed with post-processing Distance Calculation (measured in GIS software) routines) Presented in Corrected for Version 2006 TDR Projection Error Updated based on 2011 TDR Berthing at terminal 15 km 8 km N/A Standby at terminal 1 km 0.4 km N/A Kitkiata Inlet 13 km 6 km 3.2 km Wright Sound 8 km 4.5 km 1.8 km Principe Channel 10 km 6 km 3.5 km Caamaño Sound 20 km 12 km 4.3 km Caamaño Sound (solo tug) - - 13.3 km OWA Scenarios Source Levels Surrogate – from Literature In-field measurements – Valdez 120dB contour 95% radius 120 dB contour 95% radius (computed with post-processing (computed with post-processing 12 Distance Calculation routines ) routines7) Version Presented in 2010 TDR Updated based on 2011 TDR Triple Islands 10.0 km 25.5 km Browning Entrance 11.6 km 22.7 km

11 Values and figures presented in the May 2010 Application for the OWA (i.e., from the 2010 TDR) are not affected by this error. 12 Ranges were calculated directly from the output of the acoustic model using JASCO’s post-processing software rather than using GIS measurement tools

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4.3.2 Influence of the 2011 TDR on Application’s Conclusions for the CCAA The predicted effects of behavioural change within the CCAA are reduced when taking into account the correction of the 2006 TDR projection error, the updated source levels, and the updated scenarios in the 2011 TDR. Of importance, an accurate accounting for vessel speed is responsible for the main difference in sound levels between the surrogate source levels used in the 2006 TDR and those in the 2011 TDR (which are based on the Valdez measurements). The surrogate levels used in the 2006 TDR are appropriate (albeit somewhat high) for the upper end of speeds expected in the CCAA (i.e., they approximate sound levels at a speed of 13.2 knots while the anticipated vessel speed for the CCAA is 8 to 12 knots.). At a transit speed of 9.6 knots (i.e., the mean speed of vessels recorded in Valdez, Alaska), source levels derived from the Valdez measurement are 7 to 20 dB lower in most frequency bands compared to the surrogate levels used in the 2006 TDR for the CCAA scenarios. Therefore, the 2011 TDR supports the notion that vessel speed reduction is an effective mitigation measure to reduce the spatial extent of underwater noise, as stated in the May 2010 Application. The projection error correction also reduces the values presented in all CCAA-associated calculations in the May 2010 Application, including, for example, the affected area of behavioural response, the percent of the CCAA affected, and the duration of exposure. As such, conclusions regarding effects in the CCAA based on values presented in the May 2010 Application are considered conservative (i.e., predicted effects in the May 2010 Application are greater than anticipated given the projection error). Updating the escort tug numbers in the 2011 TDR scenarios also affected the predicted spatial extents of underwater noise. In Wright Sound, re-modelling in the 2011 TDR results in a stepwise decrease in the predicted 120 dB radius13 from 8 km in the 2006 TDR (and in the May 2010 Application) to 4.5 km after correcting for the projection error, to 3.0 km after incorporating the updated Valdez source levels, and ultimately to 1.8 km when the correct two-escort tug scenario is incorporated. In Caamaño Sound, re-modelling in the 2011 TDR results in a stepwise decrease in the predicted 120 dB radius from 20 km in the 2006 TDR (and in the May 2010 Application) to 12 km after correcting for the projection error, to 4.2 km after incorporating the updated Valdez source levels, and up to 4.3 km when the correct two-escort tug scenario is incorporated. A summary of how predicted areas of behavioural change in the CCAA decreased as a result of the 2011 TDR re-modelling is presented in Table 4-2. A new scenario in the 2011 TDR considers a solo escort tug transiting Caamaño Sound at 15 knots to represent tug travel through the CCAA when not accompanying a tanker14. The 120 dB radius is predicted to extend 13.3 km from the escort tug location. This result underlines the effect of vessel speeds on sound levels. Although reducing the number of vessels from three to one reduces the sound levels by 4.8 dB, increasing the speed from 9.6 knots to 15 knots increases the sound levels by 11.6 dB. While travel by a solo escort tug at 15 knots is not considered explicitly in the May 2010 Application, the

13 Calculated as the 95% radius to a threshold level of 120 dB re 1 µPa (i.e., the radius of circle containing 95% of the area ensonified above 120 dB re 1 µPa). 14 Solo tugs will adopt the vessel speed restrictions of 8-10 knots in the core humpback whale area for the period 1 May to 1 November, (exact period to be refined following marine mammal density surveys).

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original modelling in Caamaño Sound (with surrogate vessel source levels, one tug instead of two, and the projection error) predicted a 120 dB radius that extends 20 km (2006 TDR, in contrast to 4.3 km in the 2011 TDR). Therefore, a 120 dB radius of more than 13.3 km in Caamaño Sound is addressed in the May 2010 Application.

4.3.3 Influence of the 2011 TDR on the May 2010 Application’s Conclusions for the OWA Northern Gateway has committed to maintaining vessel speeds of 12 to14 knots in the “CCAA approaches” for the period 1 May to 1 November15. Furthermore, at any time of year, speeds of 16 knots are only expected in the outer sections of Dixon Entrance and Queen Charlotte Sound. Based on the 2011 TDR, which uses vessel speeds of 16 knots in the OWA scenarios, the area within which marine mammals might exhibit behavioural effects is predicted to increase from 11.6 km to 22.7 km in Browning Entrance and from 10.0 km to 25.5 km at Triple Islands. This is as a result of increased decibel levels in the higher frequency range. At an extrapolated speed of 16 knots, source levels derived from the Valdez measurement exhibited levels that are 3 to 5 dB higher for frequencies above 300 Hz compared to the surrogate levels used for the 2010 TDR. At the modelled vessel speed of 16 knots, predicted values are expected to increase in the OWA, based on the modelling results of the 2011 TDR; however, given anticipated vessel speeds, the 2011 TDR overestimates sound levels in the OWA except in the outer sections. As explained in Section 4.4.1, the projection error is not an issue in the OWA, as the error existed only in the 2006 TDR, which only considered scenarios in the CCAA. A summary of how predicted areas of behavioural change in the OWA increase as a result of the 2011 TDR re-modelling is presented in Table 4-2.

4.3.4 Influence of the Killer Whale-specific Threshold Evaluation on the Application’s Conclusions for the CCAA and OWA Killer whale-specific behavioural response criteria to underwater noise produced by large vessels do not exist. Therefore, the May 2010 Application assessed the effects of underwater noise on killer whales using three different metrics: 1. The National Marine Fisheries Service (“NMFS”)’s conservative behavioural response criterion of

120 dBRMS re 1 μPa for all marine mammals in the presence of continuous sound sources (Federal Register 2005). This criterion does not take into account differences in different species’ hearing ability.

15 Exact dates will be refined based on marine mammal density surveys and the quantitative vessel strike analysis.

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2. A killer whale species-specific behavioural change threshold of 65 dB above killer whale hearing threshold. This value16 was developed for the May 2010 Application, based on a paper by Williams et al. (2002a) that reported overt avoidance responses of NRKW in the presence of a fast moving whale watching vessel (see Section 3). 3. A killer whale species-specific behavioural change threshold of 55 dB above killer whale hearing threshold. This value17 was used should NRKW exhibit behavioural change occur at a lower intensity of sound, such as the subtle responses exhibited by NRKW in the presence of a slow moving whale watching vessel (see Section 3 of this supplement where modelling is based on information from Williams et al. 2002b and from personal communications). Based on the analysis presented in Section 3 of this supplement, use of either one of the killer whale- specific thresholds is considered appropriate. Despite this, NMFS’ highly conservative threshold (which predicted far larger areas of potential behavioural response)18 was ultimately used to draw conclusions in the May 2010 Application. As such, no changes to conclusions drawn are deemed necessary based on the evidence presented in Section 3.

4.4 Conclusions Based on corrected operational parameters presented in the 2011 TDR (i.e., use of Valdez source levels, the revised CCAA scenarios [i.e., tanker with two escort tugs], and a correction in the 2006 TDR projection error), the assessment presented in the May 2010 Application overestimated potential effects to marine mammals in the CCAA as a result of underwater noise and made the potential effects appear more spatially extensive than they are likely to be. Conversely, the May 2010 Application underestimated effects in the OWA and marine mammals in the outer sections of the OWA may exhibit behavioural change over a broader area. However, results of the 2011 TDR do not alter the determinations of significance of the effects of underwater noise from routine operations on marine mammals and fish in the CCAA and OWA, as presented in the May 2010 Application.

16 The original analysis conducted in 2006, which resulted in a predicted value of 65 dB above killer whale hearing threshold, was based on use of the sound spectrum for the slow moving vessel discussed in Williams et al. (2002b) as opposed to the fast moving vessel from Williams et al. (2002a). Re-analysis of this work (presented in Section 3) resulted in a slightly more conservative value (64 dB). 17 Modelling presented in Section 3 resulted in a slightly less conservative value (57 dB). As a result, the Application’s use of the 55dB above threshold criterion remains precautionary. 18 Based on acoustic modelling in four locations in the CCAA, the estimated area of NRKW temporary behavioural response (based on the 120 dB criterion) ranged from 36 to 256 km2. In contrast, based on the calculated killer- whale-specific behavioural criterion, sound from a vessel will exceed the 65 dB above hearing threshold only very near (i.e., within metres of) a vessel. Sounds will diminish to 55 dB above hearing threshold within 150 to 285 m (an area of up to approximately 0.3 km2). The primary reason for the large difference in estimated area is that the 120 dB criterion includes sound energy that NRKWs cannot hear, while in the 65 and 55 dB above hearing threshold criteria, NRKW hearing sensitivities are accounted for.

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4.5 References Austin, M., A. MacGillivray, D. Hannay, and M. Zykov. 2006. Gateway Environmental Management: Marine Acoustics Study. Technical report prepared for Jacques Whitford Ltd. by JASCO Research Ltd., September 2006. Chorney, N.E., A.B. McCrodan, and M.E. Austin. 2011. Northern Gateway Pipeline Project: Vessel Transit Noise, Marine Acoustics Modelling Study, 2011. Version 2.0. Technical report prepared for Stantec Consulting Ltd. for Northern Gateway Pipeline Project by JASCO Applied Sciences, January 2011. Chorney, N., G. Warner, and M. Austin. 2010. Gateway Environmental Management Vessel Transit Noise, Marine Acoustics Modelling Study, 2010. Version 4. Technical report prepared for Stantec by JASCO Applied Sciences, March 2010. COSEWIC. 2011. “Whale, Humpback | North Pacific population”. Internet Site. Last Accessed: May 19, 2011. Available at: http://www.cosewic.gc.ca/eng/sct1/searchdetail_e.cfm?id=148&StartRow=1&boxStatus=All&bo xTaxonomic=All&location=All&change=All&board=All&commonName=humpback&scienceN ame=&returnFlag=0&Page=1 Federal Register. 2005. Doc. 05-525; Endangered Fish and Wildlife; Notice of Intent to Prepare an Environmental Impact Statement. USA National Oceanic and Atmospheric Administration. MacGillivray, A. 2010. Northern Gateway Pipeline Project: Management Tanker and Escort Tug Source Level Measurement Study, Valdez Alaska, 2010. Technical report prepared for Stantec Consulting Ltd. for Northern Gateway Pipeline Project by JASCO Applied Sciences, November 2010. Malme, C.I., P.R. Miles, G.W. Miller, W.J. Richardson, D.G. Roseneau, D.H. Thomson, and C.R. Greene Jr. 1989. Analysis and Ranking of the Acoustic Disturbance Potential of Petroleum Industry Activities and Other Sources of Noise in the Environment of Marine Mammals in Alaska. Report No 6945 Prepared for U.S. Department of the Interior, Minerals Management Service. OCS Study MMS 89-0006. Williams, R., D. E. Bain, J. K. B. Ford and A. W. Trites. 2002a. Behavioural responses of male killer whales to a ‘leapfrogging’ vessel. Journal of Cetacean Research and Management 4(3):305- 310. Williams, R., A. W. Trites, and D. E. Bain. 2002b. Behavioural responses of killer whales (Orcinus orca) to whale-watching boats: opportunistic observations and experimental approaches. Journal of Zoology, London 256: 255-270.

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