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Contract No. HY/2011/03

Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road

Section between Scenic Hill and Hong Kong Boundary Crossing Facilities

 

 

 

 

 

 

Quarterly EM&A Report No. 9 (Sep 2014 to Nov 2014)

 

 

22 May 2015

 

Revision 1

 

 

 

 

 

 

 

 

 

 

 

 

 

Main Contractor                                                                                                                     Designer

Atkins new logo
 

 


 


Contents

Executive Summary

1...... Introduction.. 1

1.1                          Basic Project Information. 1

1.2                          Project Organisation. 1

1.3                          Construction Programme. 1

1.4                          Construction Works Undertaken During the Reporting Period. 1

2....... EM&A Requirement 3

2.1                          Summary of EM&A Requirements. 3

2.2                          Action and Limit Levels. 4

2.3                          Event Action Plans. 5

2.4                          Mitigation Measures. 5

3....... Environmental Monitoring and Audit 6

3.1                          Implementation of Environmental Measures. 6

3.2                          Air Quality Monitoring Results. 6

3.3                          Noise Monitoring Results. 7

3.4                          Water Quality Monitoring Results. 7

3.5                          Dolphin Monitoring Results. 7

3.6                          Mudflat Monitoring Results. 17

3.7                          Solid and Liquid Waste Management Status. 24

3.8                          Environmental Licenses and Permits. 24

4....... Environmental Complaint and Non-compliance. 25

4.1                          Environmental Exceedances. 25

4.2                          Summary of Environmental Complaint, Notification of Summons and Successful Prosecution. 27

5....... Comments, Recommendations and Conclusion.. 28

5.1                          Comments. 28

5.2                          Recommendations. 29

5.3                          Conclusions. 29

 

 

 

 

 

 

 

 

 

Figures

 

Figure 1.1        Location of the Site

Figure 2.1         Environmental Monitoring Stations     

Figure 2.2         Transect Line Layout in Northwest and Northeast Lantau Survey Areas

 

                           

Appendices

 

Appendix A       Environmental Management Structure

Appendix B       Construction Programme

Appendix C       Location of Works Areas

Appendix D       Event and Action Plan  

Appendix E       Implementation Schedule of Environmental Mitigation Measures

Appendix F       Site Audit Findings and Corrective Actions

Appendix G      Air Quality Monitoring Data and Graphical Plots

Appendix H       Noise Monitoring Data and Graphical Plots

Appendix I         Water Quality Monitoring Data and Graphical Plots

Appendix J        Dolphin Monitoring Results

Appendix K       Waste Flow Table

Appendix L       Summary of Environmental Licenses and Permits

Appendix M      Record of “Notification of Environmental Quality Limit Exceedances” and Record of “Notification of Summons and Prosecutions”

Appendix N       Cumulative Statistics on Complaints

Appendix O      Mudflat Monitoring Results


Executive Summary

The Hong Kong-Zhuhai-Macao Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern waters of the Hong Kong International Airport (HKIA).

The HKLR project has been separated into two contracts.  They are Contract No. HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between HKSAR Boundary and Scenic Hill.

China State Construction Engineering (Hong Kong) Ltd. was awarded by Highways Department as the Contractor to undertake the construction works of Contract No. HY/2011/03.  The main works of the Contract include land tunnel at Scenic Hill, tunnel underneath Airport Road and Airport Express Line, reclamation and tunnel to the east coast of the Airport Island, at-grade road connecting to the HKBCF and highway works of the HKBCF within the Airport Island and in the vicinity of the HKLR reclamation.  The Contract is part of the HKLR Project and HKBCF Project, these projects are considered to be “Designated Projects”, under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap 499) and EIA Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project.  The current Environmental Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/H for HKBCF were issued on 22 December 2014 and 19 January 2015, respectively. These documents are available through the EIA Ordinance Register. The construction phase of Contract was commenced on 17 October 2012.

BMT Asia Pacific Limited has been appointed by the Contractor to implement the Environmental Monitoring & Audit (EM&A) programme for the Contract in accordance with the Updated EM&A Manual for HKLR (Version 1.0) and will be providing environmental team services to the Contract.

This is the ninth Quarterly EM&A report for the Contract which summaries the monitoring results and audit findings of the EM&A programme during the reporting period from 1 September 2014 to 30 November 2014.

Environmental Monitoring and Audit Progress

The EM&A programme were undertaken in accordance with the Updated EM&A Manual for HKLR (Version 1.0).  A summary of the monitoring activities during this reporting period is presented as below:

Monitoring Activity

Monitoring Date

September 2014

October 2014

November 2014

Air Quality

1-hr TSP

AMS5: 4, 10, 18, 22, 26 and 30

AMS6: 4, 10, 16, 22, 26 and 30

6, 10, 16, 22 and 28

3, 7, 13, 19 and 25

24-hr TSP

AMS5: 2, 10, 12, 18, 24 and30

AMS6: 2, 8, 17, 18, 24 and 30

3, 9, 15, 21, 27 and 31

AMS5: 6, 12, 18, 24

AMS6: 6, 12, 18, 24 and 28

Noise

4, 10, 18, 22 and 30

6, 16, 22 and 28

3, 13, 19 and 25

Water Quality

1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26 and 29

1, 3, 6, 8, 10, 13, 15, 17, 20, 22, 24, 27, 29 and 31

3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26 and 28

Chinese White Dolphin

2,11,19 and 22

7, 13, 16 and 23

4, 10, 12 and 18

Mudflat Monitoring (Ecology)

6, 7, 8, 9, 20 and 21

-

-

Mudflat Monitoring (Sedimentation rate)

6

-

-

Site Inspection

3, 10, 17 and 26

3, 8, 15, 22 and 31

5, 12, 19 and 28

Due to the power interruption on 8 September 2014, the 24-hr air monitoring undertaken at AMS5 was less than 24 hours.  Therefore, the 24-hr TSP monitoring result on 8 September 2014 was considered invalid and the 24 hrs dust monitoring was rescheduled from 8 September 2014 to 10 September 2014.

Due to the motor failure of the high volume sampler, the 24-hr air monitoring result at AMS6 on 12 September 2014 was considered invalid. The 24 hrs dust monitoring was rescheduled from 12 September 2014 to 17 September 2014.

As Strong Wind Signal No. 3 was hoisted by the Hong Kong Observatory (HKO) on 15 September 2014, the water quality monitoring for mid-ebb tide of 15 September 2014 was cancelled for safety reason. Also, the dolphins monitoring was rescheduled from 15 September 2014 to 19 September 2014.As Tropical Cyclone Warning Signal No. 8 was hoisted on 16 September 2014, the 1-hr TSP monitoring at AMS5 and noise monitoring at NMS5 were rescheduled from 16 September to 18 September 2014.As 1 and 2 October 2014 were bank holidays, 1-hr dust monitoring at AMS5 and AMS6 were rescheduled to 30 September 2014.

Due to boat availability issue, the dolphins monitoring schedule was rescheduled from 17 October 2014 to 16 October 2014, from 21 October 2014 to 23 October 2014, from 6 November 2014 to 10 November 2014 and from 14 November 2014 to 18 November 2014.

Due to malfunction of HVS at AMS5 on 28 November 2014, the 24-hr air monitoring undertaken at AMS5 was less than 24 hours.  The 24-hr TSP monitoring result obtained on 28 November 2014 was considered invalid and the 24-hr dust monitoring was rescheduled from 28 November 2014 to 2 December 2014.

Breaches of Action and Limit Levels

A summary of environmental exceedances for this reporting period is as follows:

Environmental Monitoring

Parameters

Action Level (AL)

Limit Level (LL)

Air Quality

1-hr TSP

0

0

24-hr TSP

2

0

Noise

Leq (30 min)

0

0

Water Quality

Suspended solids level (SS)

9

3

Turbidity level

0

0

Dissolved oxygen level (DO)

0

0

Dolphin Monitoring

Quarterly Analysis (Sep to Nov 2014)

2

0

The Environmental Team investigated all exceedances and found that they were not project related.

All investigation reports for exceedances of the Contract have been submitted to ENPO/IEC for comments and/or follow up to identify whether the exceedances occurred related to other HZMB contracts.

Implementation of Mitigation Measures

Site inspections were carried out on a weekly basis to monitor the implementation of proper environmental pollution control and mitigation measures for the Project.  Potential environmental impacts due to the construction activities were monitored and reviewed.

Complaint Log

There were no complaints received in relation to the environmental impacts during the reporting period.


 

Notifications of Summons and Prosecutions

There were no notifications of summons or prosecutions received during this reporting period.

Reporting Changes

This report has been developed in compliance with the reporting requirements for the quarterly summary EM&A reports as required by the Updated EM&A Manual for HKLR (Version 1.0). 

The proposal for the change of Action Level and Limit Level for suspended solid and turbidity was approved by EPD on 25 March 2013.

The revised Event and Action Plan for dolphin monitoring was approved by EPD on 6 May 2013.

The original monitoring station at IS(Mf)9 (Coordinate- East:813273, North 818850) was observed inside the perimeter silt curtain of Contract HY/2010/02 on 1 July 2013, as such the original impact water quality monitoring location at IS(Mf)9 was temporarily shifted outside the silt curtain.  As advised by the Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted to facilitate safe anchorage zone of construction barges/vessels until end of 2013 subject to construction progress.  Therefore, water quality monitoring station IS(Mf)9 was shifted to 813226E and 818708N since 1 July 2013.  According to the water quality monitoring team’s observation on 24 March 2014, the original monitoring location of IS(Mf)9 was no longer enclosed by the perimeter silt curtain of Contract HY/2010/02.  Thus, the impact water quality monitoring works at the original monitoring location of IS(Mf)9 has been resumed since 24 March 2014.


1        Introduction

1.1.1       The Hong Kong-Zhuhai-Macao Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern waters of the Hong Kong International Airport (HKIA).

1.1.2       The HKLR project has been separated into two contracts. They are Contract No. HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between HKSAR Boundary and Scenic Hill.

1.1.3       China State Construction Engineering (Hong Kong) Ltd. was awarded by Highways Department (HyD) as the Contractor to undertake the construction works of Contract No. HY/2011/03.  The Contract is part of the HKLR Project and HKBCF Project, these projects are considered to be “Designated Projects”, under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap 499) and EIA Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project.  The current Environmental Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/H for HKBCF were issued on 22 December 2014 and 19 January 2015, respectively. These documents are available through the EIA Ordinance Register. The construction phase of Contract was commenced on 17 October 2012.  Figure 1.1 shows the project site boundary.

1.1.4       BMT Asia Pacific Limited has been appointed by the Contractor to implement the EM&A programme for the Contract in accordance with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and will be providing environmental team services to the Contract.  ENVIRON Hong Kong Ltd. was employed by HyD as the Independent Environmental Checker (IEC) and Environmental Project Office (ENPO) for the Project. The project organization with regard to the environmental works is provided in Appendix A.

1.1.5       This is the ninth Quarterly Environmental Monitoring and Audit (EM&A) report for the Contract which summaries the monitoring results and audit findings of the EM&A programme during the reporting period from 1 September 2014 to 30 November 2014.

1.2.1       The project organization structure and lines of communication with respect to the on-site environmental management structure with the key personnel contact names and numbers are shown in Appendix A. 

1.3                Construction Programme

1.3.1       A copy of the Contractor’s construction programme is provided in Appendix B. 

1.4                Construction Works Undertaken During the Reporting Period

1.4.1       A summary of the construction activities undertaken during this reporting period is shown in Table 1.1.  The Works areas of the Contract are showed in Appendix C.

Table 1.1          Construction Activities during Reporting Period

 

Site Area

Description of Activities

Portion X

·        Dismantling/trimming of temporary 40mm stone platform for construction of seawall

·        Stone column installation

·        Filling works behind stone platform

·        Temporary stone platform construction

·        Band drains installation

·        Sheet piling and jet grouting

·        Excavation and lateral support works for Scenic Hill Tunnel (Cut & Cover Tunnel

Portion Y

·        Access shaft construction for Scenic Hill Tunnel (SHT) & HKBCF to Airport Tunnel (HAT)

·        Utility culvert excavation

·        Pipe roofing installation for Tunnel HAT

West Portal

·        Pipe roofing installation and excavation of tunnel SHT

Airport Express Line

·        Pre-grouting and pipe piling works for Airport Express Line (AEL) access shafts

Airport Road

·        Pipe piling Cofferdam Works for HAT West Cut & Cover tunnel

Kwo Lo Wan /Airport Road

·        Works for diversion of Airport Road and Kwo Lo Wan Road

Kwo Lo Wan /Airport Road /Airport Express Line

·        Utilities detection

Kwo Lo Wan Road

·        Excavation and lateral support works at shaft 3 extension north shaft

 


 

2.1                Summary of EM&A Requirements

2.1.1       The EM&A programme requires environmental monitoring of air quality, noise, water quality, dolphin monitoring and mudflat monitoring as specified in the approved EM&A Manual.

2.1.2       A summary of Impact EM&A requirements is presented in Table 2.1. The locations of air quality, noise and water quality monitoring stations are shown as in Figure 2.1.  The transect line layout in Northwest and Northeast Lantau Survey Areas is presented in Figure 2.2.

Table 2.1          Summary of Impact EM&A Requirements

Environmental Monitoring

Description

Monitoring Station

Frequencies

Remarks

Air Quality

1-hr TSP

AMS 5 & AMS 6

At least 3 times every 6 days

While the highest dust impact was expected.

24-hr TSP

At least once every 6 days

--

Noise

Leq (30mins),
L10
(30mins) and
L90
(30mins)

NMS5

At least once per week

Daytime on normal weekdays (0700-1900 hrs).

Water Quality

·    Depth

·    Temperature

·    Salinity

·    Dissolved Oxygen (DO)

·    Suspended Solids (SS)

·    DO Saturation

·    Turbidity

·    pH

·    Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,

·    Control/Far Field Stations:
CS2 & CS(Mf)5,

·    Sensitive Receiver Stations:
SR3, SR4, SR5, SR10A & SR10B

Three times per week during mid-ebb and mid-flood tides (within ± 1.75 hour of the predicted time)

3

(1 m below water surface, mid-depth and 1 m above sea bed, except where the water depth is less than 6 m, in which case the mid-depth station may be omitted.  Should the water depth be less than 3 m, only the mid-depth station will be monitored).

Dolphin

Line-transect Methods

Northeast Lantau survey area and Northwest Lantau survey area

Twice per month

--

Mudflat

Horseshoe crabs, seagrass beds, intertidal soft shore communities, sedimentation rates and water quality

San Tau and Tung Chung Bay

Once every 3 months

--

 

2.2.1       Table 2.2 presents the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.

Table 2.2         Action and Limit Levels for 1-hour TSP, 24-hour TSP and Noise

Environmental Monitoring

Parameters

Monitoring Station

Action Level

Limit Level

Air Quality

1-hr TSP

AMS 5

352 µg/m3

500 µg/m3

AMS 6

360 µg/m3

24-hr TSP

AMS 5

164 µg/m3

260 µg/m3

AMS 6

173 µg/m3

Noise

Leq (30 min)

NMS 5

When one documented complaint is received

75 dB(A)

 

2.2.2       The Action and Limit Levels for water quality monitoring are given as in Table 2.3.

Table 2.3         Action and Limit Levels for Water Quality

Parameter (unit)

Water Depth

Action Level

Limit Level

Dissolved Oxygen (mg/L)

Surface and Middle

5.0

4.2 except 5 for Fish Culture Zone

Bottom

4.7

3.6

Turbidity (NTU)

Depth average

27.5 or 120% of upstream control station’s turbidity at the same tide of the same day;

The action level has been amended to “27.5 and 120% of upstream control station’s turbidity at the same tide of the same day” since 25 March 2013.

47.0 or 130% of turbidity at the upstream control station at the same tide of same day;

The limit level has been amended to “47.0 and 130% of turbidity at the upstream control station at the same tide of same day” since 25 March 2013.

Suspended Solid (SS) (mg/L)

Depth average

23.5 or 120% of upstream control station’s SS at the same tide of the same day;

The action level has been amended to “23.5 and 120% of upstream control station’s SS at the same tide of the same day” since 25 March 2013.

34.4 or 130% of SS at the upstream control station at the same tide of same day and 10mg/L for Water Services Department Seawater Intakes;

The limit level has been amended to “34.4 and 130% of SS at the upstream control station at the same tide of same day and 10mg/L for Water Services Department Seawater Intakes” since 25 March 2013

Notes:

               (1)    Depth-averaged is calculated by taking the arithmetic means of reading of all three depths.

               (2)    For DO, non-compliance of the water quality limit occurs when monitoring result is lower that the limit.

               (3)    For SS & turbidity non-compliance of the water quality limits occur when monitoring result is higher than the limits.

               (4)     The change to the Action and limit Levels for Water Quality Monitoring for the EM&A works was approved by EPD on 25 March 2013. Therefore, the amended Action and Limit Levels are applied for the water monitoring results obtained on and after 25 March 2013.

2.2.3       The Action and Limit Levels for dolphin monitoring are shown in Tables 2.4 and 2.5.

Table 2.4          Action and Limit Level for Dolphin Impact Monitoring

 

North Lantau Social Cluster

NEL

NWL

Action Level

STG < 70% of baseline &
ANI < 70% of baseline

STG < 70% of baseline &
ANI  < 70% of baseline

Limit Level

STG < 40% of baseline &
ANI < 40% of baseline

Remarks:

                 (1)        STG means quarterly average encounter rate of number of dolphin sightings.

                 (2)        ANI means quarterly average encounter rate of total number of dolphins.

                 (3)        For North Lantau Social Cluster, AL will be trigger if either NEL or NWL fall below the criteria; LL will be triggered if both NEL and NWL fall below the criteria.

Table 2.5          Derived Value of Action Level (AL) and Limit Level (LL)

 

North Lantau Social Cluster

NEL

NWL

Action Level

STG < 4.2  & ANI < 15.5

STG < 6.9 & ANI < 31.3

Limit Level

(STG < 2.4 & ANI < 8.9) and (STG < 3.9 & ANI < 17.9)

Remarks:

                 (1)        STG means quarterly average encounter rate of number of dolphin sightings.

                 (2)        ANI means quarterly average encounter rate of total number of dolphins.

                 (3)        For North Lantau Social Cluster, AL will be trigger if either NEL or NWL fall below the criteria; LL will be triggered if both NEL and NWL fall below the criteria.

 

2.3                Event Action Plans

2.3.1      The Event Actions Plans for air quality, noise, water quality and dolphin monitoring are annexed in Appendix D.

2.4                Mitigation Measures

2.4.1       Environmental mitigation measures for the contract were recommended in the approved EIA Report.  Appendix E lists the recommended mitigation measures and the implementation status. 


 

3        Environmental Monitoring and Audit

3.1                Implementation of Environmental Measures

3.1.1       In response to the site audit findings, the Contractor carried out corrective actions.  Details of site audit findings and the corrective actions during the reporting period are presented in Appendix F.

3.1.2       A summary of the Implementation Schedule of Environmental Mitigation Measures (EMIS) is presented in Appendix E. 

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

3.1.4       Dolphin Watching Plan was implemented during the reporting period. No dolphins inside the silt curtain were observed.  The relevant records were kept properly. 

3.2.1       The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2 respectively. Detailed impact air quality monitoring results and relevant graphical plots are presented in Appendix G.

Table 3.1         Summary of 1-hour TSP Monitoring Results During the Reporting Period

Reporting Period

Monitoring

Station

Average (mg/m3)

Range (mg/m3)

Action Level (mg/m3)

Limit Level (mg/m3)

September 2014

AMS5

45

8-117

352

500

AMS6

38

16-77

360

October 2014

AMS5

146

73-274

352

AMS6

138

92-188

360

November 2014

AMS5

164

70-305

352

AMS6

145

81-181

360

 

 

 

 

 

 

 

 

 

 

Table 3.2         Summary of 24-hour TSP Monitoring Results During the Reporting Period

Reporting Period

Monitoring

Station

Average (mg/m3)

Range (mg/m3)

Action Level (mg/m3)

Limit Level (mg/m3)

September 2014

AMS5

44

15-93

164

260

AMS6

92

40-132

173

October 2014

AMS5

75

36-116

164

AMS6

146

72-233

173

November 2014

AMS5

80

35-123

164

AMS6

104

69-151

173

 

 

 

 

 

 

 

 

 

 

3.2.2       For AMS5, no Action and Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS 5 during the reporting period.

3.2.3       For AMS6, no Action and Limit Level exceedances of 1-hr TSP level and no Limit Level exceedances of 24-hr TSP were recorded during the reporting period. An Action Level exceedance of 24-hr TSP level was recorded on 15 and 27 October 2014, respectively.

3.3                Noise Monitoring Results

3.3.1       The monitoring results for construction noise are summarized in Table 3.3 and the monitoring results and relevant graphical plots for this reporting period are provided in Appendix H.

Table 3.3          Summary of Construction Noise Monitoring Results During the Reporting Period

Reporting period

Monitoring Station

Average Leq (30 mins), dB(A)*

Range of Leq (30 mins), dB(A)*

Action Level

Limit Level Leq (30 mins), dB(A)

September 2014

NMS5

56

53-57

When one documented complaint is received

75

October 2014

60

58-62

November 2014

58

56-60

*A correction factor of +3dB(A) from free field to facade measurement was included. 

3.3.2       There were no Action and Limit Level exceedances for noise during daytime on normal weekdays of the reporting period.

3.3.3       Major noise sources during the noise monitoring included construction activities of the Contract and nearby traffic noise.

3.4.1       Impact water quality monitoring was conducted at all designated monitoring stations during the reporting period. Impact water quality monitoring results and relevant graphical plots are provided in Appendix I.

3.4.2       During the reporting period, nine Action Level exceedances and three Limit Level exceedances of suspended solid level were recorded.  No Action and Limit Level exceedance of dissolved oxygen level were recorded. No Action and Limit Level exceedances of turbidity were recorded.

3.4.3       Water quality impact sources during the water quality monitoring were the construction activities of the Contract, nearby construction activities by other parties and nearby operating vessels by other parties.

Data Analysis

3.5.1       Distribution Analysis – The line-transect survey data was integrated with the Geographic Information System (GIS) in order to visualize and interpret different spatial and temporal patterns of dolphin distribution using sighting positions.  Location data of dolphin groups were plotted on map layers of Hong Kong using a desktop GIS (ArcView© 3.1) to examine their distribution patterns in details.  The dataset was also stratified into different subsets to examine distribution patterns of dolphin groups with different categories of group sizes, young calves and activities.

3.5.2       Encounter rate analysis – Encounter rates of Chinese White Dolphins (number of on-effort sightings per 100 km of survey effort, and total number of dolphins sighted on-effort per 100 km of survey effort) were calculated in NEL and NWL survey areas in relation to the amount of survey effort conducted during each month of monitoring survey. Dolphin encounter rates were calculated in two ways for comparisons with the HZMB baseline monitoring results as well as to AFCD long-term marine mammal monitoring results. 

3.5.3       Firstly, for the comparison with the HZMB baseline monitoring results, the encounter rates were calculated using primary survey effort alone, and only data collected under Beaufort 3 or below condition would be used for encounter rate analysis.  The average encounter rate of sightings (STG) and average encounter rate of dolphins (ANI) were deduced based on the encounter rates from six events during the present quarter (i.e. six sets of line-transect surveys in North Lantau), which was also compared with the one deduced from the six events during the baseline period (i.e. six sets of line-transect surveys in North Lantau). 

3.5.4       Secondly, the encounter rates were calculated using both primary and secondary survey effort collected under Beaufort 3 or below condition as in AFCD long-term monitoring study.  The encounter rate of sightings and dolphins were deduced by dividing the total number of on-effort sightings and total number of dolphins (ANI) by the amount of survey effort for the entire quarterly period (September– November 2014).

3.5.5       Quantitative grid analysis on habitat use – To conduct quantitative grid analysis of habitat use, positions of on-effort sightings of Chinese White Dolphins collected during the quarterly impact phase monitoring period were plotted onto 1-km2 grids among Northwest Lantau (NWL) and Northeast (NEL) survey areas on GIS.  Sighting densities (number of on-effort sightings per km2) and dolphin densities (total number of dolphins from on-effort sightings per km2) were then calculated for each 1 km by 1 km grid with the aid of GIS.  Sighting density grids and dolphin density grids were then further normalized with the amount of survey effort conducted within each grid.  The total amount of survey effort spent on each grid was calculated by examining the survey coverage on each line-transect survey to determine how many times the grid was surveyed during the study period.  For example, when the survey boat traversed through a specific grid 50 times, 50 units of survey effort were counted for that grid.  With the amount of survey effort calculated for each grid, the sighting density and dolphin density of each grid were then normalized (i.e. divided by the unit of survey effort). 

3.5.6       The newly-derived unit for sighting density was termed SPSE, representing the number of on-effort sightings per 100 units of survey effort.  In addition, the derived unit for actual dolphin density was termed DPSE, representing the number of dolphins per 100 units of survey effort.  Among the 1-km2 grids that were partially covered by land, the percentage of sea area was calculated using GIS tools, and their SPSE and DPSE values were adjusted accordingly.  The following formulae were used to estimate SPSE and DPSE in each 1-km2 grid within the study area:

SPSE = ((S / E) x 100) / SA%

DPSE = ((D / E) x 100) / SA%

 

where        S = total number of on-effort sightings

D = total number of dolphins from on-effort sightings

E = total number of units of survey effort

SA% = percentage of sea area

3.5.7       Behavioural analysis – When dolphins were sighted during vessel surveys, their behaviour was observed.  Different activities were categorized (i.e. feeding, milling/resting, traveling, socializing) and recorded on sighting datasheets.  This data was then input into a separate database with sighting information, which can be used to determine the distribution of behavioural data with a desktop GIS.  Distribution of sightings of dolphins engaged in different activities and behaviours would then be plotted on GIS and carefully examined to identify important areas for different activities of the dolphins. 

3.5.8       Ranging pattern analysis – Location data of individual dolphins that occurred during the 3-month baseline monitoring period were obtained from the dolphin sighting database and photo-identification catalogue.  To deduce home ranges for individual dolphins using the fixed kernel methods, the program Animal Movement Analyst Extension, was loaded as an extension with ArcView© 3.1 along with another extension Spatial Analyst 2.0.  Using the fixed kernel method, the program calculated kernel density estimates based on all sighting positions, and provided an active interface to display kernel density plots.  The kernel estimator then calculated and displayed the overall ranging area at 95% UD level.

Summary of Survey Effort and Dolphin Sightings

3.5.9       During the period of September to November 2014, six sets of systematic line-transect vessel surveys were conducted to cover all transect lines in NWL and NEL survey areas twice per month.

3.5.10    From these surveys, a total of 892.88 km of survey effort was collected, with 97.1% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility).  Among the two areas, 343.71 km and 549.17 km of survey effort were conducted in NEL and NWL survey areas respectively.

3.5.11    The total survey effort conducted on primary lines was 644.60 km, while the effort on secondary lines was 248.28 km.  Both survey effort conducted on primary and secondary lines were considered as on-effort survey data. A summary table of the survey effort is shown in Annex I of Appendix J.

3.5.12    During the six sets of monitoring surveys in September to November 2014, a total of 24 groups of 93 Chinese White Dolphins were sighted.  All except two dolphin sightings were made during on-effort search.  Twenty on-effort sightings were made on primary lines, while another two on-effort sightings were made on secondary lines.  In this quarterly period, all dolphin groups were sighted in NWL, while none of them were sighted in NEL. A summary table of the dolphin sightings is shown in Annex II of Appendix J.

Distribution

3.5.13    Distribution of dolphin sightings made during monitoring surveys in September to November 2014  was shown in Figure 1 of Appendix J. Similar to recent quarters, the majority of dolphin sightings made in the present quarter were concentrated in the northwestern end of the North Lantau region, with higher concentration around Lung Kwu Chau (Figure 1 of Appendix J).  A few other sightings were scattered around Sha Chau and to the north of the airport platform.  No dolphin sighting was made in NEL in the present quarter.

3.5.14    Notably, none of the dolphin groups was sighted in the vicinity of the HKLR03/ HKBCF reclamation sites or along the entire alignment of Tuen Mun-Chek Lap Kok Link (TMCLKL) during this quarterly period (Figure 1 of Appendix J). 

3.5.15    Sighting distribution of the present impact phase monitoring period (September to November 2014) was compared to the one during the baseline monitoring period (September to November 2011).  In the present quarter, dolphins have completely avoided the NEL region, which was in stark contrast to their frequent occurrence around the Brothers Islands and in the vicinity of HKBCF reclamation site during the baseline period (Figure 1 of Appendix J). The nearly complete abandonment of NEL region by the dolphins has been consistently recorded in the past seven quarters, which have resulted in extremely low dolphin encounter rates in this area.

3.5.16    In NWL survey area, dolphin occurrence was also very different between the baseline and impact phase quarters.  During the present impact monitoring period, there appeared to be much fewer dolphins occurred in the middle portion of North Lantau region than during the baseline period, where dolphins supposedly moved between their core areas around Lung Kwu Chau and the Brothers Islands(Figure 1 of Appendix J). Moreover, more dolphins were sighted near Sha Chau and Black Point during the baseline period than during the present impact monitoring period (Figure 1 of Appendix J).  Notably, a number of dolphin sightings were made to the west of Chek Lap Kok airport (especially near the HKLR09 alignment) during the baseline period, but the dolphins were not sighted there at all during the present impact phase period.

3.5.17    Another comparison in dolphin distribution was made between the two quarterly periods of autumn months in 2013 and 2014 was also made (Figure 2 of Appendix J).  Among the two autumn periods, no dolphin sighting was made in NEL in the autumn of 2014, while there were two sightings made there in the autumn of 2013.  Moreover, a lot more dolphin sightings were made in the middle and western portions of North Lantau waters (especially between Black Point and Lung Kwu Chau, as well as around Sha Chau) in the autumn of 2013 than in the autumn of 2014.  The comparison indicated that dolphin usage in North Lantau waters was further diminished in autumn of 2014 from the same period in the previous year.

Encounter Rate

3.5.18    For the three-month study period in September, October and November 2014, the encounter rates of Chinese White Dolphins deduced from the survey effort and on-effort sighting data from the primary transect lines under favourable conditions (Beaufort 3 or below) from each of the survey areas are shown in Table 3.4.  The average encounter rates deduced from the six sets of surveys were also compared with the ones deduced from the baseline monitoring period in September to November 2011 (See Table 3.5).

Table 3.4         Dolphin Encounter Rates (Sightings Per 100 km of Survey Effort) During three Reporting Period (Sep –Nov 2014) 

Survey Area

Dolphin Monitoring

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 surve
y effort)

Primary Lines Only

Primary Lines Only

Northeast  Lantau

Set 1 (2 & 11 Sep 2014)

0.00

0.00

Set 2 (19 & 22 Sep 2014)

0.00

0.00

Set 3 (7 & 13 Oct 2014)

0.00

0.00

Set 4 (16 & 23 Oct 2014)

0.00

0.00

Set 5 (4 & 10 Nov 2014)

0.00

0.00

Set 6 (12 & 18 Nov 2014)

0.00

0.00

Northwest Lantau

Set 1 (2 & 11 Sep 2014)

5.72

28.58

Set 2 (19 & 22 Sep 2014)

4.34

18.80

Set 3 (7 & 13 Oct 2014)

13.13

42.67

Set 4 (16 & 23 Oct 2014)

0.00

0.00

Set 5 (4 & 10 Nov 2014)

4.60

24.54

Set 6 (12 & 18 Nov 2014)

2.84

8.53

 


 

Table 3.5     Comparison of Average Dolphin Encounter Rates between Reporting Period (Sep – Nov 2014) and Baseline Monitoring Period (Sep – Nov 2011)

Survey Area

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)

Reporting Period

Baseline Monitoring Period

Reporting Period

Baseline Monitoring Period

Northeast Lantau

0.00

6.00 ± 5.05

0.00

22.19 ± 26.81

Northwest Lantau

5.10 ± 4.40

9.85 ± 5.85

20.52 ± 15.10

44.66 ± 29.85

Note:
The encounter rates deduced from the baseline monitoring period have been recalculated based only on the survey effort and on-effort sighting data made along the primary transect lines under favourable conditions)

3.5.19    To facilitate the comparison with the AFCD long-term monitoring results, the encounter rates were also calculated for the present quarter using both primary and secondary survey effort.  The encounter rates of sightings (STG) and dolphins (ANI) in NWL were 4.18 sightings and 16.17 dolphins per 100 km of survey effort respectively, while the encounter rates of sightings (STG) and dolphins (ANI) in NEL were both nil.

3.5.20    In NEL, the average dolphin encounter rates (both STG and ANI) in the present three-month impact monitoring period were zero, and such low occurrence of dolphins in NEL have been consistently recorded in the past seven quarters (Table 3.6).

3.5.21    It is a serious concern that dolphin occurrence in NEL in the seven quarters (0.0-1.0 for ER(STG) and 0.0-3.9 for ER(ANI)) have been exceptionally low when compared to the baseline period (Table 3.6).  In fact, the present quarter was the eighth consecutive quarters being assessed that have triggered the Action Levels under the Event and Action Plan.  As discussed recently in Hung (2014), the dramatic decline in dolphin usage of NEL waters in 2012 and 2013 (including the declines in abundance, encounter rate and habitat use in NEL, as well as shifts of individual core areas and ranges away from NEL waters) was possibly related to the HZMB construction works that were commenced in 2012.

3.5.22    Moreover, the average dolphin encounter rates (STG and ANI) in NWL during the present impact phase monitoring period were also much lower (reductions of 48.2% and 54.1% respectively) than the ones recorded in the 3-month baseline period, indicating a noticeable decline in dolphin usage of this survey area during the present construction period (Table 3.7). 

Table 3.6     Comparison of Average Dolphin Encounter Rates in Northeast Lantau Survey Area from All Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep – Nov 2011)

 

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)

September-November 2011 (Baseline)

6.00 ± 5.05

22.19 ± 26.81

December 2012-February 2013 (Impact)

3.14 ± 3.21

6.33 ± 8.64

March-May 2013 (Impact)

0.42 ± 1.03

0.42 ± 1.03

June-August 2013 (Impact)

0.88 ± 1.36

3.91 ± 8.36

September-November 2013 (Impact)

1.01 ± 1.59

3.77 ± 6.49

December 2013-February 2014 (Impact)

0.45 ± 1.10

1.34 ± 3.29

March-May 2014 (Impact)

0.00

0.00

June-August 2014 (Impact)

0.42 ± 1.04

1.69 ± 4.15

September-November 2014 (Impact)

0.00

0.00

Note:
The encounter rates deduced from the baseline monitoring period have been recalculated based only on survey effort and on-effort sighting data made along the primary transect lines under favourable conditions.

Table 3.7        Comparison of Average Dolphin Encounter Rates in Northwest Lantau Survey Area from All Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep – Nov 2011)

 

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)

September-November 2011 (Baseline)

9.85 ± 5.85

44.66 ± 29.85

December 2012-February 2013 (Impact)

8.36 ± 5.03

35.90 ± 23.10

March-May 2013 (Impact)

7.75 ± 3.96

24.23 ± 18.05

June-August 2013 (Impact)

6.56 ± 3.68

27.00 ± 18.71

September-November 2013 (Impact)

8.04 ± 1.10

32.48 ± 26.51

December 2013-February 2014 (Impact)

8.21 ± 2.21

32.58 ± 11.21

March-May 2014 (Impact)

6.51 ± 3.34

19.14 ± 7.19

June-August 2014 (Impact)

4.74 ± 3.84

17.52 ± 15.12

September-November 2014 (Impact)

5.10 ± 4.40

20.52 ± 15.10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note: The encounter rates deduced from the baseline monitoring period have been recalculated based only on survey effort and on-effort sighting data made along the primary transect lines under favourable conditions.

 

3.5.23    A two-way ANOVA with repeated measures and unequal sample size was conducted to examine whether there were any significant differences in the average encounter rates between the baseline and impact monitoring periods.  The two variables that were examined included the two periods (baseline and impact phases) and two locations (NEL and NWL). 

3.5.24    For the comparison between the baseline period and the present quarter (eighth quarter of the impact phase being assessed), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.0222 and 0.0662 respectively.  If the alpha value is set at 0.1, significant difference was detected between the baseline and present quarters in both dolphin encounter rates of STG and ANI.

3.5.25    For the comparison between the baseline period and the cumulative quarters in impact phase (i.e. first eight quarters of the impact phase being assessed), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.0019 and 0.0006 respectively.  Even if the alpha value is set at 0.01, significant differences were detected in both the average dolphin encounter rates of STG and ANI (i.e. between the two periods and the locations).

3.5.26    As indicated in both dolphin distribution patterns and encounter rates, dolphin usage has been significantly reduced in NEL waters in the present quarterly period, and such low occurrence has been consistently documented in previous quarters.  This raises serious concern, as the decline in dolphin usage could possibly link to the HZMB-related construction activities in NEL waters.

3.5.27    To ensure the continuous usage of NEL waters by the dolphins, every possible measure should be implemented by the contractors and relevant authorities to minimize all disturbances to the dolphins, as a future marine park around the Brothers Islands will be established in this important dolphin habitat as a compensation measure for the habitat loss resulted from the HKBCF reclamation works. Unless such declining trend can be reverted after the establishment of the Brothers Islands Marine Park, there should be a presumption against further reclamation in North Lantau waters as suggested in Hung (2013, 2014).

3.5.28    It should be noted that dolphin usage in NWL have also been diminished progressively in the past few quarters (Table 3.7), and such downward trend should be closely monitored, as the potential impacts of HZMB-related works on the dolphins may have been extended to the entire North Lantau region.

Group Size

3.5.29    Group size of Chinese White Dolphins ranged from one to 13 individuals per group in North Lantau region during September – November 2014.  The average dolphin group sizes from these three months were compared with the ones deduced from the baseline period in September to November 2011, as shown in Table 3.8.

Table 3.8         Comparison of Average Dolphin Group Sizes between Reporting Period (Sep Nov 2014) and Baseline Monitoring Period (Sep– Nov 2011)

 

Average Dolphin Group Size

Reporting Period

Baseline Monitoring Period

Overall

3.88 ± 2.69 (n = 24)

3.72 ± 3.13 (n = 66)

Northeast Lantau

0.00

3.18 ± 2.16 (n = 17)

Northwest Lantau

3.88 ± 2.69 (n = 24)

3.92 ± 3.40 (n = 49)

 

 

 

 

 

 

 

3.5.30    The average dolphin group sizes in the entire North Lantau region as well as in NWL waters during September – November 2014 were similar to the ones recorded during the three-month baseline period (Table 3.8).  Sixteen of the 24 groups were composed of 1-4 individuals only, while there was only one dolphin group with more than 10 individuals.

3.5.31    Distribution of dolphins with larger group sizes (five individuals or more per group) during the present quarter is shown in Figure 3 of Appendix J, with comparison to the one in baseline period.  During the autumn of 2014, distribution of the majority of larger dolphin groups were concentrated near Lung Kwu Chau (Figure 3 of Appendix J). This distribution pattern was quite different from the baseline period, when the larger dolphin groups were distributed more evenly in NWL waters with a few more sighted in NEL waters (Figure 3 of Appendix J).

3.5.32    Notably, none of the larger dolphin groups were sighted near the HKLR03 reclamation site in the present monitoring period (Figure 3 of Appendix J).

 

Habitat Use

3.5.33    From September to November 2014, the most heavily utilized habitats by Chinese White Dolphins mainly concentrated around Lung Kwu Chau (Figures 4a and 4b of Appendix J).  None of the grids in NEL recorded the presence of dolphins in the present quarter.  Moreover, all grids near HKLR03/HKBCF reclamation sites, HKLR09 or TMCLKL alignment did not record any presence of dolphins during on-effort search in the present quarterly period.

3.5.34    However, it should be emphasized that the amount of survey effort collected in each grid during the three-month period was fairly low (6-12 units of survey effort for most grids), and therefore the habitat use pattern derived from the three-month dataset should be treated with caution.  A more complete picture of dolphin habitat use pattern will be presented when more survey effort for each grid will be collected throughout the impact phase monitoring programme.

3.5.35    When compared with the habitat use patterns during the baseline period, dolphin usage in NEL was dramatically different from the present impact monitoring period (Figure 5 of Appendix J).  During the baseline period, nine grids between Siu Mo To and Shum Shui Kok recorded moderately high to high dolphin densities, which was in stark contrast to complete absence of dolphins during the present impact phase period (Figure 5 of Appendix J). 

3.5.36    The density patterns between the baseline and impact phase monitoring periods were also different in NWL, with higher dolphin usage around Sha Chau, near Black Point, to the west of the airport, as well as between Pillar Point and airport platform during the baseline period (Figure 5 of Appendix J).

3.5.37    The absence of dolphins in the identified important habitats around the Brothers Islands and Shum Shui Kok in consecutive quarters in 2013-14 is of serious concern.  The future Brothers Islands Marine Park will be established in this area upon the completion of HKBCF reclamation works, as an important compensation measure for the associated habitat loss.  As suggested recently in Hung (2014), such low usage of dolphins in this important habitat in the past two years was likely related to the on-going HZMB-related construction works.  Continuous monitoring of such diminished use should be continued in this important dolphin habitat in the upcoming quarters.

Mother-calf Pairs

3.5.38    During the three-month study period, only four unspotted juveniles (UJ) were sighted in NWL survey areas.  These young calves comprised of 4.3% of all animals sighted, which was lower than the percentage recorded during the baseline monitoring period (6.8%).

3.5.39    All four young calves were sighted around Lung Kwu Chau (Figure 6 of Appendix J), which was very different from their distribution pattern during the baseline period when young calves were sighted throughout the NWL survey area as well as a few sighted in NEL waters.  None of the four young calves were sighted in the vicinity of the HKBCF/HKLR03 reclamation sites and HKLR09/TMCLKL alignments during the present quarter (Figure 6 of Appendix J).

Activities and Associations with Fishing Boats

3.5.40    A total of three dolphin sightings were associated with feeding and socializing activities respectively during the three-month study period.  The percentage of sightings associated with feeding activities during the present quarter (8.3%) was lower than the one recorded during the baseline period (11.6%).  On the contrary, the percentage of socializing activities during the present impact phase monitoring period (4.2%) was slightly lower than the one recorded during the baseline period (5.4%).  One group of five dolphins was also engaged in traveling activity during the present quarter.

3.5.41    Distribution of dolphins engaged in feeding, socializing and traveling activities during the present three-month period is shown in Figure 7 of Appendix J.  The three sightings associated with feeding and traveling activities all occurred to the north of Lung Kwu Chau, while the lone sighting associated with socializing activity was located to the north of the airport (Figure 7 of Appendix J). Distribution of dolphin sightings associated with these activities during the impact phase was very different from the distribution pattern of these activities during the baseline period (Figure 7 of Appendix J).

3.5.42    During the three-month period, none of the 24 dolphin groups was found to be associated with an operating fishing vessels in North Lantau waters.  The extremely rare events of fishing boat association in the present and previous quarters were consistently found, and were likely related to the recent trawl ban being implemented in December 2012 in Hong Kong waters.

Photo-identification and Individual Range Use

3.5.43    From  September to November 2014, over 2,000 digital photographs of Chinese White Dolphins were taken during the impact phase monitoring surveys for the photo-identification work.

3.5.44    In total, 26 individuals sighted 49 times altogether were identified (see summary table in Annex III of Appendix J and photographs of identified individuals in Annex IV of Appendix J). All of these 49 re-sightings were made in NWL.

3.5.45    The majority of identified individuals were sighted only once or twice during the three-month period, with the exception of five individuals (NL202, NL214, NL233, NL286 and WL05) being sighted thrice and two individuals (NL48 and NL182) being sighted four times.

3.5.46    Five of these 26 individuals were also sighted in West Lantau waters during the HKLR09 monitoring surveys for the same three-month period, showing their movement between North and West Lantau regions.

3.5.47    Five recognized females (NL104, NL182, NL202, NL233 and NL256) were accompanied with their calves during their re-sightings.  Some of these mothers were frequently sighted with their calves throughout the HKLR03 impact phase monitoring period since October 2012.

Individual range use

3.5.48    Ranging patterns of the 26 individuals identified during the three-month study period were determined by fixed kernel method, and are shown in Annex V of Appendix J.

3.5.49    All identified dolphins sighted in this quarter were utilizing their range use in NWL (and some also in WL), but have avoided the NEL waters where many of them have utilized as their core areas in the past (Annex V of Appendix J). This is in contrary to the extensive movements between NEL and NWL survey areas observed in the earlier impact monitoring quarters as well as during the baseline period. 

3.5.50    For many individuals that have previously utilized the Brothers Islands as their major core area of activities, they have apparently shifted their range use away from this important habitat (e.g. NL136, NL182, NL259; Annex V of Appendix J).  Such shifts of range use and core area use were also documented by Hung (2014), as well as in the past monitoring quarters in 2013 and 2014 under the present study.

3.5.51    On the other hand, there were a few individuals sighted in NWL and NEL waters consistently in the past, but have extended their range use to WL waters in the present quarter (e.g. NL259).  It should be further monitored to examine whether there has been any consistent shifts of home ranges of individuals from North Lantau to West Lantau, which could also possibly be related to the HZMB-related construction works.

Action Level / Limit Level Exceedance

3.5.52    There were two Action Level exceedances of dolphin monitoring for the quarterly monitoring data (September – November 2014). According to the Contractor’s information, the marine activities undertaken for HKLR03 during the quarter of September 2014 to November 2014 included stone platform construction, reclamation, stone column installation, band drain installation, excavation of stone platform, surcharge activities, construction of seawall and temporary drainage diversion There is no evidence showing the current AL non-compliance directly related to the construction works of HKLR03, although the generally increased amount of vessel traffic in NEL during the impact phase has been partly contributed by HKLR03 works since October 2012. It should also be noted that reclamation work under HKLR03 (adjoining the Airport Island) situates in waters which has rarely been used by dolphins in the past, and the working vessels under HKLR03 have been travelling from source to destination in accordance with the Marine Travel Route to minimize impacts on Chinese White Dolphin.  In addition, the contractor will implement proactive mitigation measures such as avoiding anchoring at Marine Department’s designated anchorage site – Sham Shui Kok Anchorage (near Brothers Island) as far as practicable.

3.5.53    A two-way ANOVA with repeated measures and unequal sample size was conducted to examine whether there were any significant differences in the average encounter rates between the baseline and impact monitoring periods.  The two variables that were examined included the two periods (baseline and impact phases) and two locations (NEL and NWL).

3.5.54    For the comparison between the baseline period and the present quarter (eighth quarter of the impact phase), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.0222 and 0.0662 respectively.  If the alpha value is set at 0.1, significant difference was detected between the baseline and present quarters in both encounter rates of STG and ANI.

3.5.55    For the comparison between the baseline period and the cumulative quarters in impact phase (i.e. first eight quarters of the impact phase), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.0019 and 0.0006 respectively.  Even if the alpha value is set at 0.01, significant difference was detected in both the average dolphin encounter rates of STG and ANI (i.e. between the two periods and the locations).

3.5.56    The AFCD monitoring data during September to November 2014 has been reviewed by the dolphin specialist, and no dolphin was sighted from 108.93 km of survey effort on primary lines in NEL during the same quarter.  This review has confirmed that the extremely low occurrence of dolphins reported by the HKLR03 monitoring survey in autumn 2014 in NEL is accurate.

3.5.57    There is no evidence showing that the sources of impact directly related to the construction works of HKLR03 that may have affected the dolphin usage in the NEL region.

3.5.58    All dolphin protective measures are fully and properly implemented in accordance with the EM&A Manual. The Contractor will continue to provide training for skippers to ensure that their working vessels travel from source to destination to minimize impacts on Chinese White Dolphin and avoid anchoring at Marine Department’s designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as far as practicable. 

3.5.59    A meeting was held on 9 December 2014 with attendance of ENPO, Resident Site Staff (RSS), Environmental Team (ET) and dolphin specialist for Contract No. HY/2010/02, RSS, ET, dolphin specialist and main Contractor for Contract No. HY/2011/03. The discussion/recommendation as recorded in the minutes of the meeting, which might be relevant to HKLR03 Contract are summarized below.

3.5.60    It was concluded that the HZMB works is one of the contributing factors affecting the dolphins. It was also concluded the contribution of impacts due to the HZMB works as a whole (or individual marine contracts) cannot be quantified nor separate from the other stress factors.

3.5.61    It was reminded that the ETs shall keep reviewing the implementation status of the dolphin related mitigation measures and remind the contractor to ensure the relevant measures were fully implemented.

3.5.62    It was recommended that the marine works of HZMB projects should be completed as soon as possible so as to reduce the overall duration of impacts and allow the dolphins population to recover as early as possible.

3.5.63    It was also recommended that the marine works footprint (e.g., reduce the size of peripheral silt curtain) and vessels for the marine works should be reduced as much as possible, and vessels idling / mooring in other part of the North Lantau shall be avoided whenever possible. The team for HY/2010/02 advised that the contractor was already using large capacity sand barge so as to reduce the number of vessel traffics, and had already submitted a proposal to resize the peripheral silt curtain.

3.5.64    It was suggested that the protection measures (e.g., speed limit control) for the proposed Brothers Island Marine Park (BMP) shall be brought forward as soon as possible before its establishment so as to provide a better habitat for dolphin recovery. It was noted that under the Regular Marine Travel Route Plan, the contractors have committed to reduce the vessel speed in BMP.

3.5.65    There was a discussion on exploring possible further mitigation measures, for example, controlling the underwater noise. It was noted that the EIA reports for the projects suggested several mitigation measures, all of which have been implemented.

3.6                Mudflat Monitoring Results

Sedimentation Rate Monitoring

3.6.1       The baseline sedimentation rate monitoring was in September 2012 and impact sedimentation rate monitoring was undertaken on 6 September 2014. The mudflat surface levels at the four established monitoring stations and the corresponding XYZ HK1980 GRID coordinates are presented in Table 3.8 and Table 3.9.

Table 3.8          Measured Mudflat Surface Level Results

Baseline Monitoring
(September 2012)

Impact Monitoring
(
September 2014)

Monitoring Station

Easting (m)

Northing (m)

Surface Level

Easting (m)

Northing (m)

Surface Level

(mPD)

(mPD)

S1

810291.160

816678.727

0.950

810291.165

816678.754

1.030

S2

810958.272

815831.531

0.864

810958.261

815831.522

0.940

S3

810716.585

815953.308

1.341

810716.593

815953.320

1.450

S4

811221.433

816151.381

0.931

811221.424

816151.402

1.146

 


 

Table 3.9          Comparison of measurement  

Comparison of measurement

Remarks and Recommendation

Monitoring Station

Easting (m)

Northing (m)

Surface Level
(mPD)

S1

0.005

0.027

0.080

Level continuously increased

S2

-0.011

-0.009

0.076

Level continuously increased

S3

0.008

0.011

0.109

Level continuously increased

S4

-0.009

0.054

0.215

Level continuously increased

 

3.6.2       This measurement result was generally and relatively higher than the baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.

Water Quality Monitoring

3.6.3       The mudflat monitoring covered water quality monitoring data.  Reference was made to the water quality monitoring data of the representative water quality monitoring station (i.e. SR3) as in the EM&A Manual.  The water quality monitoring location (SR3) is shown in Figure 2.1. 

3.6.4       Impact water quality monitoring in San Tau (monitoring station SR3) was conducted in September 2014.  The monitoring parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).

3.6.5       The Impact monitoring result for SR3 were extracted and summarised below:

Table 3.10       Impact Water Quality Monitoring Results (Depth Average)

Date

Mid Ebb Tide

Mid Flood Tide

DO (mg/L)

Turbidity (NTU)

SS (mg/L)

DO (mg/L)

Turbidity (NTU)

SS (mg/L)

01-Sep-14

6.48

6.50

5.20

6.01

7.35

6.50

03-Sep-14

6.17

3.45

1.95

7.36

3.15

3.70

05-Sep-14

5.96

5.35

4.50

8.40

5.80

6.80

08-Sep-14

6.19

7.50

10.95

6.48

7.30

6.45

10-Sep-14

5.49

25.05

27.50

5.44

9.10

8.55

12-Sep-14

5.76

17.05

17.10

5.71

12.20

12.50

15-Sep-14*

-

-

-

5.65

5.25

5.65

17-Sep-14

6.00

5.85

6.20

6.50

6.45

6.30

19-Sep-14

6.28

4.30

2.60

7.18

3.05

5.20

22-Sep-14