2               Land-based Dolphin Behaviour and Movement Monitoring

Monitoring Requirements

2.1         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 before, during and after bridge construction.

2.2         Following the requirement in the EM&A Manual Section 10.4.3 & 10.6.3 and approved Proposal for Land-based Dolphin Behaviour and Movement Monitoring (the Proposal) dated 24 January 2013, 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

2.3         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 2.

Monitoring Frequency

2.4         Thirty-One days of monitoring were carried out during the construction phase.

Monitoring Day

2.5         A total of 31 sessions with 179 hours and 17 minutes of theodolite tracking were conducted from Shum Wat shore-based station on the 18th, 19th, 20th, 21st, 22nd, 23rd, 25th, 27th and 28th March 2013, 1st, 2nd, 4th, 5th, 7th, 8th, 9th, 10th and 11th April 2013 and 8th, 9th, 10th, 11th, 12th, 13th, 15th, 17th, 18th, 19th, 23rd, 24th and 29th July 2013  when bored piling activities were concurrently conducted.

 

2.6         The land-based theodolite tracking schedule is shown in Appendix B. 

Monitoring Results

2.7         A total of 31 days of land-based dolphin behaviour and movement monitoring was conducted in March, April and July 2013, when bored piling activities were concurrently conducted. During those dates, 92.3% of effort was conducted in favourable weather conditions. Dolphins were successfully tracked from shore on 18 of 31 days of effort, and a total of 70 dolphin groups were tracked, in groups ranging from 1 to 9 members.

 

2.8         Detailed monitoring methodology and results can be found in Appendix C.

 

2.9         According to the Land-based Dolphin Behaviour and Movement Monitoring Impact Phase Monitoring Report prepared by Dolphin Specialist as shown in Appendix C, summary of the land-based dolphin behavior monitoring results is shown in Table 2.1 and 2.2.

Table 2.1.  Values of all response variables in the baseline and construction phases, with the percentage change.  Split by the presence and absence of vessels by time of day, size of group, and maximum number of vessels present. (The numerical values highlighted in blue indicated that the values recorded in impact monitoring period have triggered the Action Level (20% higher or lower than the baseline period), while the ones highlighted in red indicated a triggering of Limit Level (40% higher or lower than the baseline period). Only the cells highlighted in yellow have found significant differences (two-sample t-test with unequal variance, p<0.05) between the values recorded in impact and baseline monitoring periods, while no significant difference was found in other comparisons even though some have triggered the Action or Limit Level.)

 

 

Speed (km/hr)

Reorientation rate (degrees/surfacing)

Linearity

Inter-breath interval (sec)

 

Base

Constr

% Diff

Base

Constr

% Diff

Base

Constr

% Diff

Base

Constr

% Diff

Vessels absent

3.60

3.40

5.6

50.3

56.7

12.8

0.618

0.291

52.9

51.2

51.2

0.0

    Morning

3.46

3.65

5.4

45.4

62.4

37.4

0.676

0.303

55.2

53.9

79.4

47.3

    Afternoon

3.80

3.15

17.2

57.2

51.0

10.9

0.536

0.280

47.8

47.3

23.0

51.4

    Individual

3.39

3.14

7.2

46.9

51.8

10.5

0.733

0.080

89.0

57.2

33.3

41.7

    Group

3.91

3.51

10.3

55.2

58.8

6.6

0.455

0.382

16.0

42.6

58.9

38.3

 

Vessels present

3.77

 

3.27

13.4

50.5

56.5

12.0

0.577

0.481

16.6

43.3

49.8

14.8

    Morning

3.74

3.13

16.2

49.9

53.7

7.5

0.606

0.535

11.8

45.0

48.3

7.2

    Afternoon

3.93

3.67

6.7

52.7

65.1

23.5

0.454

0.320

29.7

36.2

54.1

49.6

    Individual

3.42

2.96

13.4

50.8

55.2

8.7

0.542

0.458

15.5

45.0

50.6

12.5

    Group

4.26

3.46

18.6

50.0

57.4

14.7

0.625

0.496

20.7

41.1

49.2

19.7

    1 vessel

3.91

3.13

20.0

48.8

56.3

15.4

0.572

0.429

24.9

36.9

48.7

32.0

    2 vessels

3.74

3.60

3.6

55.8

52.0

6.7

0.559

0.457

18.1

53.6

56.0

4.5

    3 vessels

4.26

3.27

23.2

45.8

69.2

50.9

0.689

0.518

24.8

62.5

44.0

29.6

 

 

Table 2.2.  Proportion of time spent in each behavioural state in the absence and presence of vessels within 500 m, during the baseline and construction phases.  Results and significance of the z-test for two proportions presented for three comparisons: 1) with no vessels present in the baseline vs. during construction; 2) with vessels present in the baseline vs. during construction; and 3) with vessels present in the baseline vs. with no vessels present during construction. (The numerical values highlighted in blue indicated that the values recorded in impact monitoring period have triggered the Action Level (20% higher or lower than the baseline period), while the ones highlighted in red indicated a triggering of Limit Level (40% higher or lower than the baseline period). Only the cells highlighted in yellow have found significant differences between the values recorded in impact and baseline monitoring periods, while no significant difference was found in other comparisons even though some have triggered the Action or Limit Level.)

 

 

Baseline

Construction

No vessels

Base-Constr

Vessels

Base-Constr

Vessels Base - 

No vessels Constr

Behavioural state

No vessels

Vessels

No vessels

Vessels

z-value

p-value

z-value

p-value

z-value

p-value

Feeding

0.23

0.44

0.45

0.40

2.944

0.003

-0.499

0.617

-0.273

0.787

Milling

0.20

0.21

0.13

0.24

-1.425

0.153

0.565

0.569

1.883

0.060

Resting

0.08

0.03

0.02

0.01

-2.178

0.029

-0.780

0.435

0.698

0.484

Travelling

0.48

0.32

0.41

0.34

-1.030

0.303

0.269

0.787

-1.404

0.162

 

 

Event and Action Plan

 

2.10     The detailed Event and Action Plan is presented in Table 2.3.

 

Table 2.3    Event and Action Plan on Dolphin Movement and Behaviour

EVENT

ACTION

ET Leader

IEC

SO

Contractor

Action Level

With the numerical values presented in Tables 2.1-2.2, any of the response variable for dolphin movement patterns (speed, inter-breath interval, reorientation rate & linearity) and behaviour (proportion of time spent in each behavioural state) recorded in the construction phase monitoring is 20% higher or lower than that recorded in the baseline monitoring, action level should be triggered

 

1. Repeat statistical data analysis to confirm findings;

2. Review all available and relevant data to ascertain if differences are as a result of natural variation or seasonal differences;

3. Identify source(s) of impact;

4. Inform the IEC, SO and Contractor;

5. Check monitoring data;

6. Carry out audit to ensure all dolphin protective measures are implemented fully and additional measures be proposed if necessary

 

1. Check monitoring data submitted by ET and Contractor;

2. Discuss monitoring with the ET and the Contractor;

 

 

1. Discuss with the IEC the repeat monitoring and any other measures proposed by the ET;

2. Make agreement on measures to be implemented.

 

1. Inform the SO and confirm notification of the non- compliance in writing;

2. Discuss with the ET and the IEC and propose measures to the IEC and the SO;

3. Implement the agreed measures.

 

Limit Level

With the numerical values presented in Tables 2.1-2.2, any of the response variable for dolphin movement patterns (speed, inter-breath interval, reorientation rate & linearity) and behaviour (proportion of time spent in each behavioural state) recorded in the construction phase monitoring is 40% higher or lower than that recorded in the baseline monitoring, limit level should be triggered

 

1. Repeat statistical data analysis to confirm findings;

2. Review all available and relevant data to ascertain if differences are as a result of natural variation or seasonal differences;

3. Identify source(s) of impact;

4. Inform the IEC, SO and Contractor;

5. Check monitoring data;

6. Carry out audit to ensure all dolphin protective measures are implemented fully and additional measures be proposed if necessary

7. Discuss additional dolphin monitoring and any other potential mitigation measures (e.g. consider to temporarily stop relevant portion of construction activity) with the IEC and Contractor.

 

 

1. Check monitoring data submitted by ET and Contractor;

2. Discuss monitoring with the ET and the Contractor;

3. Review proposals for additional monitoring and any other measures submitted by the Contractor and advise ER accordingly.

 

1. Discuss with the IEC the repeat monitoring and any other measures proposed by the ET;

2. Make agreement on measures to be implemented.

 

1. Inform the SO and confirm notification of the non- compliance in writing;

2. Discuss with the ET and the IEC and propose measures to the IEC and the SO;

3. Implement the agreed measures.

Abbreviations: ET – Environmental Team, IEC – Independent Environmental Checker, SO – Supervising Officer

 

2.11     Detailed monitoring methodology and results can be found in Appendix C.

 

2.12     According to Table 2.1, there were ten Action Level exceedances (one on speed, two on re-orientation rate, four on linearity and three on inter-breath interval) and nine Limit Level exceedances were recorded  (one on re-orientation rate, four on linearity and four on inter-breath interval). However, only three in linearity that have exceeded the Limit Levels were statistically significant.

 

2.13     According to Table 2.2, there were three Limit Level exceedances (one on feeding with no vessels present, two on resting with and without vessels present). Moreover, there was one Action Level exceedance (for milling with no vessels present). However, only the ones on feeding and resting without vessels present between the phases were statistically significant.

 

2.14     As the Environmental Team of the Contract, all the monitoring data and statistical data analysis as presented in Appendix C have been checked and reviewed according to Table 2.3.

 

 

2.15     No direct evidence that the exceedances were due to the bored piling activities under the Contract according to the Land-based Dolphin Behaviour and Movement Monitoring Impact Phase Monitoring Report in Appendix C:

 

Ø   The majority of the exceedances are not statistically significant due to small sample size;

Ø   Different type of vessels recorded during baseline and construction may contribute the significant different values of response variables between baseline and construction phases; and

Ø   Natural seasonal variation may cause the different dolphin behaviours and movements between baseline and construction phase dolphin monitoring.

 

Implementation Status of Environmental Mitigation Measures

2.16     In order to minimize impact on dolphin behavior and movement, dolphin protection measures as described below were properly implemented during the marine works for the Contract:

 

Ø   Regular marine travel route for marine vessels were implemented properly in accordance with the submitted plan and relevant records were kept properly.

 

Ø   Acoustic decoupling measures for the stationary equipment (generators, winch generators and air compressors) mounted on boards were adopted according to the approved Acoustic Decoupling Measures Plan, EP Condition 3.7 and EM&A Manual, Section 10.2.18.

 

Ø   Dolphin exclusion zone and dolphin watching plan according to EM&A Manual, Section 10.2.12 and 10.2.17 respectively..