6               Dolphin-related Monitoring

Monitoring Requirements

 

6.1         According to Section 10 of the EM&A Manual, four kinds of ecological monitoring works are required during the construction phase, namely dolphin monitoring, construction-phase underwater noise monitoring, dolphin behavior monitoring and land-based dolphin behavior and movement monitoring.

 

6.2         The monitoring work shall be undertaken by suitably qualified specialist(s), (i.e. dolphin specialist and bio-acoustician), who shall have sufficient (at least 5-10 years) relevant post-graduate experience and publication in the respective aspects. They should be approved by Agriculture, Fisheries and Conservation Department (AFCD) and Environmental Protection Department (EPD).

 

Dolphin Monitoring (Line-transect Vessel Survey)

Monitoring Requirements

6.3         According to EM&A Manual Section 10.3.2, a dolphin monitoring programme should be set up to verify the predictions of impacts and to ensure that there are no unforeseen impacts on the dolphin population during construction phase.

 

6.4         Following the requirement in the EM&A Manual Section 10.4.1, the dolphin monitoring should adopt line-transect vessel survey method, and cover the following line-transect survey areas as in AFCD annual marine mammal monitoring programme.

Monitoring Location

6.5         For this contract, dolphin monitoring will be carried out in the West Lantau (WL) along the line transect as depicted in Figure 1 of Appendix I-1. The co-ordinates of all transect lines are shown in Table 6.1.

 

Table 6.1           Co-ordinates of transect lines in WL survey area

Line No.

Easting

Northing

Line No.

Easting

Northing

1

Start Point

803750

818500

7

Start Point

800200

810450

1

End Point

803750

815500

7

End Point

801400

810450

2

Start Point

803750

815500

8

Start Point

801300

809450

2

End Point

802940

815500

8

End Point

799750

809450

3

Start Point

802550

814500

9

Start Point

799400

808450

3

End Point

803700

814500

9

End Point

801430

808450

4

Start Point

803120

813600

10

Start Point

801500

807450

4

End Point

801640

813600

10

End Point

799600

807450

5

Start Point

801100

812450

11

Start Point

800300

806500

5

End Point

802900

812450

11

End Point

801750

806500

6

Start Point

802400

811500

12

Start Point

801760

805450

6

End Point

800660

811500

12

End Point

800700

805450

Monitoring Frequency

6.6         Dolphin transect survey was carried out at least twice a month (i.e. complete all the transect lines of West Lantau survey area twice per month) throughout the construction period.

Monitoring Day

6.7         Dolphin monitoring was carried out on 5th and 10th July 2013. The dolphin monitoring schedule for the reporting period is shown in Appendix D. 

Monitoring Results

6.8         From these surveys, a total of 60.3 km of survey effort was collected, with 100.0% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility) Out of the 60.3 km of survey effort, the total survey effort conducted on primary lines (the vertical lines perpendicular to the coastlines) was 40.2 km.

 

6.9         15 groups of 63 Chinese White Dolphins were sighted from primary lines. These sightings were evenly distributed throughout the WL survey area, which was very different from previous months of monitoring when most sightings were made at the middle and southern portions of the survey area. Notably, two dolphin sightings were made near the HKLR09 alignment.

 

6.10     Dolphin encounter rates deduced from the survey effort and on-effort sighting data made under favourable conditions (Beaufort 3 or below) are shown in Table 6.2.

 

Table 6.2               Dolphin encounter rates (sightings per 100 km of survey effort) in July’s surveys

 

Encounter rate (STG)     (no. of on-effort dolphin sightings per 100 km of survey effort)

Encounter rate (ANI)            (no. of dolphins from all on-effort sightings per 100 km of survey effort)

Primary Lines Only

Primary Lines Only

WL

Set 1: July 5th

38.7

159.5

Set 2: July 10th

35.8

153.5

 

6.11     A total of 28 re-sightings of known individual Chinese White Dolphins were made during the July’s surveys.

 

6.12     No adverse impact on Chinese white dolphins was noticeable from general observations.

 

6.13     Evaluation of impacts on dolphins due to construction work will be conducted in the quarterly EM&A report.

 

6.14     Detailed monitoring methodology and results can be found in Appendix I-1.

 

Construction-phase Underwater Noise Monitoring

Monitoring Requirements

6.15     According to EM&A Manual Section 10.3.3 and 10.4.2, construction-phase underwater noise monitoring has to be carried out to verify the assessment outcome in the EIA and to collect field data of this construction activity. The actual underwater noise level of bored piling will be monitored during the pile construction in the waters to the west of the Airport for HKLR.

 

6.16     Following the requirement in the EM&A Manual Section 10.6.2, construction-phase underwater noise monitoring will be constructed for 10 days from the start of the bored piling activities for the first three pier sites during the bored piling process in the first three sits in the waters to the west of Airport.

Monitoring Location

6.17     The equipment was positioned at an appropriate and safe distance from a barge (about 100m away from the center of the pier) where the piling work was carried out at the pier site to monitor the underwater noise during the bored piling activities. After anchoring, the boat would drift within the radius of the anchor (about 5m), which was unavoidable.

 

6.18     In July 2013, bored piling work was carried out at Pier site no. 0. The approximate locations of the monitoring stations are depicted in Figure 5. The co-ordinates of the monitoring station are shown in Table 6.3.

 

Table 6.3           Co-ordinates of underwater noise monitoring stations

Pier No.

Station

Easting

Northing

0

R3

802556

815708

 

6.19     Due to programme change, the first three piers were changed to P48, P52 and P0 instead of P20, P47 or P49 proposed in the methodology statement. While the location of impact monitoring has changed, the position of the station remained around 100m away from the piers as proposed. The change in monitoring location will not affect comparison against Action and Limit level.

Monitoring Day

6.20     R3 was monitored on 11th, 12th, 15th-19th and 22nd-24th July 2013. A total of 10 days of underwater noise monitoring were conducted at R3 during the bored piling activities for P0. The underwater noise monitoring schedule for the reporting period is shown in Appendix D.  Since the commencement of the underwater noise monitoring, a total of 30-day results from the start of the bored piling activities for the first three pier sites were collected.

Monitoring Equipment

6.21     PAM004, a proprietary product of Sea Mammal Research Unit (SMRU), was adopted for impact underwater noise monitoring. It is the same equipment used in baseline monitoring. While this is different from the system proposed in the method statement, the difference in sensitivity and pre-amplifier gain will not affect the monitoring results. Therefore, this still allows compatible comparison of the measurement. Copies of calibration certificates are provided in Appendix C.

Monitoring Methodology

6.22     The data recorded by PAM004 were transmitted to a receiving station on a boat via cable. The data were viewed on a laptop computer in real time by an operator from Cinotech who has been well trained and technically supported by SMRU for the operation.

 

6.23     The RMS sound pressure level re 1µPa were checked against the Action Level and Limit Level (170 and 180 dB re 1µPa respectively).

Monitoring Results

6.24     The underwater noise monitoring results are summarized in Table 6.4. Hourly average RMS and graphical presentations of underwater noise monitoring are shown in Appendix I-2. The averaging period was in general from 9am to 6pm, depending on the availability of the data as the monitoring might have temporarily paused due to bad weather or to give way for barge movement.

 

Table 6.4     Summary Table of Underwater Noise Monitoring Results during the Reporting Month

 

Date

Pier No.

Station

Underwater Noise (dB re 1µPa)

Period

Max

Average

Min

11-Jul-13

0

R3

156.8

139.8

117.7

10-18

12-Jul-13

0

R3

164.6

139.7

115.4

9-18

15-Jul-13

0

R3

161.6

135.3

119.7

9-18

16-Jul-13

0

R3

153.9

133.6

120.5

9-18

17-Jul-13

0

R3

149.8

134.4

120.1

9-18

18-Jul-13

0

R3

149.9

138.4

122.5

9-18

19-Jul-13

0

R3

159.1

138.8

120.3

9-18

22-Jul-13

0

R3

155.2

140.0

122.2

9-18

23-Jul-13

0

R3

154.8

141.9

122.4

9-18

24-Jul-13

0

R3

155.1

141.2

120.8

9-18

Remarks: All underwater noise monitoring was conducted during the bored piling activities

Frequency: 70 Hz – 125 kHz

 

6.25     As shown in the table above, no Action/Limit Level exceedance was recorded.

 

6.26     A total of 30-day results from the start of the bored piling activities for the first three pier sites were collected, further analysis on PSD and within audiological range of frequencies of Chinese white dolphin will be carried out and presented in a separate report.


Event and Action Plan 

 

6.27     Should non-compliance of the criteria occur, action in accordance with the Action Plan in Appendix K shall be carried out.

 

 

Dolphin Behaviour Monitoring (Acoustic)

Monitoring Requirements

6.28     According to EM&A Manual Section 10.3.4, acoustic behavior and movement of Chinese White Dolphin near the bored piling sites should be monitored during bridge construction.

Monitoring Location

6.29     The dedicated acoustic surveys with calibrated hydrophone deployment were conducted in the western side of Lantau Island during the construction phase. The research vessel followed a predefined route for systematic search effort in West Lantau waters to cover the HKLR alignment in Northwest and West Lantau waters (in particular the area near the first three bored piling sites), where dolphins will be potentially disturbed by the bored piling works.

 

6.30     The EARs were deployed at two locations: 1) near the bridge alignment (N22°17.222, E113°53.016), about 500 m from the first three bored piling sites (Site B2), and 2) at a less disturbed site away from the bridge alignment as control site, off Fan Lau (N22°11.827, 113°50.648; Site B1).  EAR B2 was in water depth 4 m, and EAR B1 in 7 m.

Monitoring Day

6.31     In July 2013, a total of 12 days of acoustic monitoring surveys were conducted on the 9th, 11th, 12th, 15th, 16th, 17th, 18th, 22nd, 23rd, 24th, 25th and 26th, when bored piling activities were concurrently conducted. The schedule is shown in Appendix D. 

 

Monitoring Results

6.32     In July, 783.8 km of survey effort were conducted to search for dolphins in the western and northwestern waters of Lantau.  A total of 46 groups, numbering 170 dolphins, were sighted during these surveys.  In addition, 52 sound samples with 4.2 hours of recordings were taken from some of these dolphin groups.  Moreover, the EARs were deployed since early July 2013 at Fan Lau (site B1) and near the bridge alignment (Site B2), which will be recovered at the end of the construction phase monitoring. 

 

6.33     Detailed monitoring methodology and results can be found in Appendix I-3.

 

Land-based Dolphin Behaviour and Movement Monitoring

Monitoring Requirements

6.34     According to EM&A Manual Section 10.3.5, land-based theodolite tracking has to be carry out to study dolphin behaviour near bored piling work site, and examine their north-south movement across the bridge alignment during after bridge construction.

 

6.35     Following the requirement in the EM&A Manual Section 10.4.3 and 10.6.3, the monitoring should be conducted at the three pier sites for 30 days from the start of bored piling activities in the waters to the west of Airport.

Monitoring Location

6.36     A theodolite tracking station was set up in Sham Wat located along the northwest coast of Lantau Island (22o16.10’ N. and 113o52.32’ E) as depicted in Figure 6.

Monitoring Frequency

6.37     Thirty days of monitoring would be carried out during the construction phase. Additional land-based dolphin behavior and movement monitoring (twice per month) throughout the construction period will be commenced subject to the detailed analysis of 30 days monitoring results.

Monitoring Day

6.38     In July 2013, a total of 13 sessions with 74.1 hours of theodolite tracking were conducted from Shum Wat shore-based station on the 8th, 9th, 10th, 11th, 12th, 13th, 15th, 17th, 18th, 19th, 23rd, 24th and 29th, when bored piling activities were concurrently conducted. The schedule is shown in Appendix D. 

Monitoring Results

6.39     More than 93% of effort was conducted in favourable weather conditions during those days.  Dolphins were successfully tracked from shore on 12 of the 13 days of efforts, and a total of 57 dolphin groups were tracked.  A total of 1,536 fixes of their positions were collected, and another 2,174 fixes were also made from locations of various vessels (e.g. fishing boats, high-speed ferries), to examine the level of vessel traffic in the study area.  At the end of the construction phase monitoring period, the data will be used for the analyses on movement pattern, speed, reorientation rate, linearity, inter-breath interval, and north-south movement of Chinese White Dolphins.

 

6.40     Detailed monitoring methodology and results can be found in Appendix I-4.