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. 8
3.6 Mudflat Monitoring Results. 20
3.7 Solid and Liquid Waste Management
Status. 33
3.8 Environmental Licenses and Permits. 33
4....... Environmental Complaint and Non-compliance. 34
4.1 Environmental Exceedances. 34
4.2 Summary of Environmental Complaint,
Notification of Summons and Successful Prosecution. 34
5....... Comments, Recommendations
and Conclusion.. 36
5.1 Comments. 36
5.2 Recommendations. 36
5.3 Conclusions. 36
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/K for HKBCF
were issued on 22 December 2014 and 11 April 2016, respectively. These
documents are available through the EIA Ordinance Register. The construction
phase of Contract was
commenced on 17 October 2012.
BMT Hong Kong 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 twenty-third Quarterly EM&A report for the Contract
which summarizes the monitoring results and audit findings of the EM&A
programme during the reporting period from 1 March 2018 to 31 May 2018.
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
|
March 2018
|
April 2018
|
May 2018
|
Air
Quality
|
1-hr TSP
|
2, 8, 14, 20, 26 and 29
|
4, 10, 16, 20 and 26
|
2, 8, 14, 18, 24 and 29
|
24-hr TSP
|
1, 7, 13, 19, 23 and 28
|
3, 9, 13, 19, 25 and 30
|
8, 11, 17, 23 and 28 for AMS5
5, 11, 17, 23 and 28 for AMS6
|
Noise
|
8, 14, 20, and 26
|
4, 10, 16 and 26
|
2, 8, 14, 24 and 29
|
Water Quality
|
2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 26, 28
and 30
|
2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25, 27
and 30
|
2, 4, 7,
9, 11, 14, 16, 18, 21,
23, 25, 28 and 30
|
Chinese
White Dolphin
|
8, 12, 20 and 23
|
10, 17, 19 and 25
|
7, 10, 16 and 30
|
Mudflat Monitoring (Ecology)
|
3, 4, 11, 14, 17 and 21
|
-
|
-
|
Mudflat Monitoring (Sedimentation rate)
|
18
|
-
|
-
|
Site Inspection
|
1,7, 14, 21 and 27
|
4,11, 18 and 27
|
7, 10, 16 and 29
|
Due to foggy weather and low visibility, water quality monitoring at
all stations during flood tide on 5 March 2018 were cancelled.
Due to the boat unavailability, the dolphin monitoring was
rescheduled from 6 March 2018 to 8 March 2018, from 16 March 2018 to 20 March
2018, from 24 April 2018 to 25 April 2018, from 11 May 2018 to 10 May 2018 and
from 23 May 2018 to 30 May 2018.
Due to power interruption of the high volume sampler (HVS), monitoring
time for TSP monitoring on 5 May 2018 at AMS5 (Ma Wan Chung Village) was less
than 24-hr. The 24-hr TSP monitoring was rescheduled from 5 May 2018 to 8 May
2018.
As there was a barge at station IS8 (coordinate: 814251E, 818412N)
during monitoring for both ebb and flood tide on 9 May 2018, the water quality
monitoring at station IS8 was temporarily conducted at
coordinate: 814263E, 818360N during ebb tide and at coordinate:
814299E, 818369N during flood tide on 9 May 2018.
As there was a barge at station IS8 (coordinate: 814251E, 818412N)
during monitoring for flood tide on 23 May 2018, the water quality monitoring
at station IS8 was temporarily conducted at coordinate: 814275E, 818382N
during flood tide on 23 May 2018.
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)
|
3
|
0
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin
Monitoring
|
Quarterly
Analysis (Mar 2018 to May 2018)
|
0
|
1
|
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 was one complaint (complaint no. COM-2017-129) received in relation
to the environmental impacts (Cleanliness problem at East Coast Road) in
December 2017. Based on the investigation result, there was no direct evidence
showing that that the complaint was related to Contract No. HY/2011/03 for
complaint no. COM-2017-129.
A complaint (complaint no. COM-2018-132) and a follow-ups of complaint no. COM-2018-132 were received in February 2018
and March 2018 respectively. Based on our
investigation result, the complaint was related to Contract No. HY/2011/03 for complaint
no. COM-2018-132 and a follow-ups of
complaint no. COM-2018-132.
A summary of environmental complaints for previous reporting period and
the reporting period is as follows:
Environmental Complaint
No.
|
Date of Complaint
Received
|
Description of Environmental
Complaint
|
COM-2017-129
|
ENPO¡¦s email to
the Supervising Officer¡¦s Representative and Contractor on 8 January 2018
that HyD received a complaint lodged by a member of the public regarding
cleanliness problem at East Coast Road on 29 December 2017
|
Cleanliness
problem at East Coast Road
|
COM-2018-132
|
HyD (SOR referred the email from HyD to Contractor and ET on 13
February 2018) and EPD (ENPO referred the email from EPD to SOR, SOR sent the
email to Contractor and ET on 14 February 2018)
|
Complaint
about Dust, Water Quality, Construction Waste, Noise and Vibration for the
Contract
|
Follow-ups of Complaint No COM-2018-132
|
HyD (SOR referred the email from HyD to the Contractor and ET on 16
March 2018) and EPD (ENPO referred the email from EPD to SOR, who sent the
email to the Contractor and ET on 21 March 2018)
|
Dust
and Construction Waste
|
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 subsequent 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: 813273E,
818850N) 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.
Transect lines 1, 2, 7, 8, 9 and 11 for dolphin monitoring have been
revised due to the obstruction of the permanent structures associated with the
construction works of HKLR and the southern viaduct of TM-CLKL, as well as
provision of adequate buffer distance from the Airport Restricted Areas. The EPD issued a memo and confirmed that
they had no objection on the revised transect lines on 19 August 2015.
The water quality monitoring stations at IS10 (Coordinate: 812577E,
820670N) and SR5 (811489E, 820455N) are located inside Hong Kong International
Airport (HKIA) Approach Restricted Areas. The previously granted Vessel's Entry
Permit for accessing stations IS10 and SR5 were expired on 31 December 2016. During
the permit renewing process, the water quality monitoring location was shifted
to IS10(N) (Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E,
820978N) on 2, 4 and 6 January 2017 temporarily. The permit has been granted by
Marine Department on 6 January 2017. Thus, the impact water quality monitoring
works at original monitoring location of IS10 and SR5 has been resumed since 9
January 2017.
Transect lines 2, 3, 4, 5, 6 and 7 for dolphin monitoring have been
revised and transect line 24 has been added due to the presence of a work zone
to the north of the airport platform with intense construction activities in
association with the construction of the third runway expansion for the Hong
Kong International Airport. The EPD issued a memo and confirmed that they had
no objection on the revised transect lines on 28 July 2017. The alternative
dolphin transect lines are adopted starting from August¡¦s dolphin monitoring.
A new water quality monitoring team has been employed for carrying out
water quality monitoring work for the Contract starting from 23 August 2017.
Due to marine work of the Expansion of Hong Kong International Airport into a
Three-Runway System (3RS Project), original locations of water quality
monitoring stations CS2, SR5 and IS10 are enclosed by works boundary of 3RS
Project. Alternative impact water quality monitoring stations, naming as
CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and were adopted
starting from 23 August 2017 to replace the original locations of water quality
monitoring for the Contract.
The role and responsibilities as the ET Leader of the Contract was
temporarily taken up by Mr Willie Wong instead of Ms Claudine Lee from 25
September 2017 to 31 December 2017.
The topographical condition of the water monitoring stations SR3
(Coordinate: 810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A
(Coordinate: 823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot
be accessed safely for undertaking water quality monitoring. The water quality monitoring
has been temporarily conducted at alternative stations, namely SR3(N)
(Coordinate 810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and
SR10A(N) (Coordinate: 823644E, 823484N) since 1 September 2017. The water
quality monitoring at station SR10B was temporarily conducted at Coordinate:
823683E, 823187N on 1, 4, 6, 8 September 2017 and has been temporarily
fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E, 823159N)
since 11 September 2017. Proposal for permanently relocating the aforementioned
stations was approved by EPD on 8 January 2018.
According to
latest information received in July 2018, the works area WA7 was handed over to
other party on 28 February 2018 instead of 31 January 2018.
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/K for HKBCF were issued on
22 December 2014 and 11 April 2016, respectively. These documents are available
through the EIA Ordinance Register. The construction
phase of Contract was commenced on 17 October 2012. The works area WA7 was handed over to other
party on 28 February 2018. Figure 1.1 shows the project site
boundary.
1.1.5 This
is the twenty-third Quarterly
Environmental Monitoring and Audit (EM&A) report for the Contract which
summarizes the monitoring results and audit findings of the EM&A programme
during the reporting period from 1 March 2018 to 31 May 2018.
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
Description of
Activities
|
Site Area
|
Dismantling/trimming of
temporary 40mm stone platform for construction of seawall
|
Portion X
|
Construction of seawall
|
Portion X
|
Loading and unloading of
filling materials
|
Portion X
|
Backfilling at Scenic
Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Works for
diversion
|
Airport Road
|
Utilities
detection
|
Airport Road/ Airport Express Line/ East Coast Road
|
Establishment of
site access
|
Airport Road/ Airport Express Line/ East Coast Road
|
E&M/
Backfilling/ Bitumen works for HKBCF to Airport Tunnel West (Cut & Cover
Tunnel)
|
Airport Road
|
E&M/
Backfilling/ Bitumen works for HKBCF to Airport Tunnel East (Cut & Cover
Tunnel)
|
Portion X
|
Finishing works for
Highway Operation and Maintenance Area Building
|
Portion X
|
Finishing works for
Scenic Hill Tunnel West Portal Ventilation building
|
West Portal
|
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)
|
NMS 5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡P Depth
¡P Temperature
¡P Salinity
¡P Dissolved Oxygen (DO)
¡P Suspended Solids (SS)
¡P DO Saturation
¡P Turbidity
¡P pH
|
¡P Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,
¡P Control/Far Field
Stations:
CS2 & CS(Mf)5,
¡P Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A & SR10B
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 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 triggered 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 triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
2.3.1
The Event Actions Plans for air quality, noise,
water quality and dolphin monitoring are annexed in Appendix
D.
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 have rectified all observations identified in environmental site
inspections undertaken during the reporting period. 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 Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
March 2018
|
AMS5
|
37
|
7 ¡V 57
|
352
|
500
|
AMS6
|
33
|
19 ¡V 52
|
360
|
April 2018
|
AMS5
|
48
|
13 ¡V 93
|
352
|
AMS6
|
49
|
20 ¡V 88
|
360
|
May 2018
|
AMS5
|
12
|
7 ¡V 25
|
352
|
AMS6
|
27
|
11 ¡V 45
|
360
|
Table 3.2 Summary
of 24-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
March
2018
|
AMS5
|
59
|
43 ¡V 94
|
164
|
260
|
AMS6
|
101
|
78 ¡V 169
|
173
|
April
2018
|
AMS5
|
60
|
32 ¡V 84
|
164
|
AMS6
|
94
|
50 ¡V 122
|
173
|
May
2018
|
AMS5
|
39
|
28 ¡V 54
|
164
|
AMS6
|
144
|
73 ¡V 217
|
173
|
3.2.2
No
Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5 and AMS6
during the reporting month. No Action and Limit Level exceedances of 24-hr TSP
were recorded at AMS5. Two Action Level exceedances of 24-hr TSP were recorded
at AMS6 during the reporting period.
3.2.3
Record of notification
of environmental quality limit exceedances are provided in Appendix M.
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
Obtained 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)
|
March
2018
|
NMS5
|
59
|
59 ¡V 60
|
When one documented complaint is received
|
75
|
April
2018
|
60
|
57 ¡V 63
|
May
2018
|
57
|
56 ¡V 59
|
3.3.2
No Action and Limit Level exceedances for noise
were recorded 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 and insect 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.
3.4.1
3.4.2
No Action and Limit Level exceedances for
turbidity level and dissolved oxygen level were recorded during the reporting
period. 3 Action Level exceedances of suspended solids level were recorded
during the reporting period. The exceedances of suspended solids level recorded
during reporting period were considered to be attributed to other external
factors such as sea condition, rather than the contract works. The exceedances
were considered as non-contract related. Record of ¡§Notification of
Environmental Quality Limit Exceedances¡¨ is provided in Appendix
M.
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 ¡V 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 ¡V 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 (STG)
and total number of dolphins (ANI) by the amount of survey effort for the
present quarterly period.
3.5.5
Quantitative grid analysis on habitat use ¡V 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 NWL and 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 ¡V 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 ¡V 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 March to May 2018, 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 791.83 km of survey effort was collected, with 89.8% 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, 290.90 km and 500.93 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 576.61 km, while the
effort on secondary lines was 215.22km. Survey effort
conducted on both 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 March and May 2018, nine groups of 30 Chinese White Dolphins were sighted, with the summary table of the dolphin
sightings shown in in Annex II of Appendix J. All dolphin sightings were made during on-effort search, while eight of the nine on-effort dolphin
sightings were made on primary lines.
3.5.13
In addition, all
dolphin groups were sighted in NWL, and no dolphin was sighted at all in NEL. In fact, since August 2014, only two
sightings of two lone dolphins were made respectively in NEL during HKLR03 monitoring
surveys.
Distribution
3.5.14
Distribution of
dolphin sightings made during HKLR03 monitoring surveys conducted from March to May 2018 is shown in Figure 1 of Appendix J. The majority of sightings were made at
the western end of the North Lantau region, with slightly higher concentration
of sightings near Lung Kwu Chau (Figure 1 of
Appendix J). Several sightings were
also made near Black Point as well as a few kilometres to the west of Sha Chau
(Figure
1 of Appendix J). As consistently recorded in the previous monitoring quarters, the
dolphins were completely absent from the central and eastern portions of North
Lantau waters (Figure 1 of Appendix J).
3.5.15
All dolphin
sightings were located far away from the HKLR03 and HKBCF reclamation sites as
well as along the alignments of HKLR09 and Tuen Mun-Chek Lap Kok Link (TMCLKL) (Figure 1 of
Appendix J).
3.5.16 Sighting distribution of dolphins during the present impact phase
monitoring period (March-May 2018) was drastically different from the one
during the baseline monitoring period (Figure 1
of Appendix J). In the present
quarter, dolphins have disappeared from the NEL region, which was in stark
contrast to their frequent occurrence around the Brothers Islands, near Shum
Shui Kok 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 20 quarters of HKLR03 monitoring, which has resulted in
zero to extremely low dolphin encounter rates in this area.
3.5.17
In NWL survey
area, dolphin occurrence was also significantly different between the baseline
and impact phase periods. During
the present impact monitoring period, dolphins were less frequently sighted
here, and mainly at the western end of the area, which was in contrary to their
frequent occurrences throughout the area during the baseline period (Figure 1 of Appendix
J).
3.5.18
Another comparison
in dolphin distribution was made between the six quarterly periods of spring
months in 2013-18 (Figure 2 of Appendix J). Among the six
spring periods, dolphins were sighted regularly in NWL waters in 2013 and 2014,
but their usage there was dramatically reduced in the four subsequent spring
periods, with their only occurrences mostly concentrated at the western end of
the survey area (Figure 2 of Appendix J).
Encounter Rate
3.5.19
During
the present three-month study period, 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) for
each set of the surveys in NEL and NWL 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 (September ¡V November 2011) (Table
3.5).
3.5.20 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 2.12
sightings and 7.07
dolphins per 100 km of survey effort
respectively, while the encounter rates of sightings (STG) and dolphins (ANI)
in NEL were both nil for this quarter.
Table 3.4 Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) During Reporting Period
(March
¡V May 2018)
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 survey effort)
|
Primary Lines Only
|
Primary Lines Only
|
Northeast Lantau
|
Set 1 (8 & 12 Mar 2018)
|
0.00
|
0.00
|
Set 2 (20 & 23 Mar 2018)
|
0.00
|
0.00
|
Set 3 (10 & 17 Apr 2018)
|
0.00
|
0.00
|
Set 4 (19 & 25 Apr 2018)
|
0.00
|
0.00
|
Set 5 (7 & 10 May
2018)
|
0.00
|
0.00
|
Set 6 (16 & 30 May
2018)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (8 & 12 Mar 2018)
|
1.73
|
5.19
|
Set 2 (20 & 23 Mar 2018)
|
12.32
|
56.69
|
Set 3 (10 & 17 Apr 2018)
|
0.00
|
0.00
|
Set 4 (19 & 25 Apr 2018)
|
3.24
|
4.87
|
Set 5 (7 & 10 May
2018)
|
0.00
|
0.00
|
Set 6 (16 & 30 May
2018)
|
0.00
|
0.00
|
Table 3.5 Comparison of average dolphin encounter rates from impact monitoring
period (March to May 2018) and baseline monitoring period (September ¡V November
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
|
0.0
|
6.00 ¡Ó 5.05
|
0.0
|
22.19 ¡Ó 26.81
|
Northwest Lantau
|
2.88 ¡Ó 4.81
|
9.85 ¡Ó 5.85
|
11.12 ¡Ó 22.46
|
44.66 ¡Ó 29.85
|
Notes:
1) 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.
2) ¡Ó
denotes the standard deviation of the average encounter rates.
3.5.21
In NEL, the average dolphin encounter rates
(both STG and ANI) in the present three-month impact monitoring period were
both zero with no on-effort sighting being made, and such extremely low
occurrence of dolphins in NEL have been consistently recorded in the past 20
quarters of HKLR03 monitoring (Table 3.6). This is a serious
concern as the dolphin occurrence in NEL in the past few years (0.0-1.0 for
ER(STG) and 0.0-3.9 for ER(ANI)) have remained exceptionally low when compared
to the baseline period (Table 3.6). Dolphins have been virtually
absent from NEL waters since January 2014, with only three groups of six
dolphins sighted there since then despite consistent and intensive survey
effort being conducted in this survey area.
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 ¡V Nov 2011)
Monitoring Period
|
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 ¡Ó 5.05
|
22.19 ¡Ó 26.81
|
December 2012-February 2013 (Impact)
|
3.14 ¡Ó 3.21
|
6.33 ¡Ó 8.64
|
March-May 2013 (Impact)
|
0.42 ¡Ó
1.03*
|
0.42 ¡Ó
1.03*
|
June-August 2013 (Impact)
|
0.88 ¡Ó 1.36
|
3.91 ¡Ó 8.36
|
September-November 2013 (Impact)
|
1.01 ¡Ó
1.59
|
3.77 ¡Ó
6.49
|
December 2013-February 2014 (Impact)
|
0.45 ¡Ó 1.10
|
1.34 ¡Ó 3.29
|
March-May 2014 (Impact)
|
0.00*
|
0.00*
|
June-August 2014 (Impact)
|
0.42 ¡Ó 1.04
|
1.69 ¡Ó 4.15
|
September-November 2014 (Impact)
|
0.00
|
0.00
|
December 2014-February 2015 (Impact)
|
0.00
|
0.00
|
March-May 2015 (Impact)
|
0.00*
|
0.00*
|
June-August 2015 (Impact)
|
0.44 ¡Ó 1.08
|
0.44 ¡Ó 1.08
|
September-November 2015 (Impact)
|
0.00
|
0.00
|
December 2015-February 2016 (Impact)
|
0.00
|
0.00
|
March-May 2016 (Impact)
|
0.00*
|
0.00*
|
June-August 2016 (Impact)
|
0.00
|
0.00
|
September-November 2016 (Impact)
|
0.00
|
0.00
|
December 2016-February 2017 (Impact)
|
0.00
|
0.00
|
March-May 2017 (Impact)
|
0.00*
|
0.00*
|
June-August 2017 (Impact)
|
0.00
|
0.00
|
September-November 2017 (Impact)
|
0.00
|
0.00
|
December 2017-February 2018 (Impact)
|
0.00
|
0.00
|
March-May 2018 (Impact)
|
0.00*
|
0.00*
|
Notes:
1) 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.
2) ¡Ó denotes the standard deviation of the
average encounter rates.
3) The encounter rates in spring months were in blue
and marked with asterisk.
3.5.22
On the
other hand, the
average dolphin encounter rates (STG and ANI) in NWL during the present impact
phase monitoring period (reductions of 70.8% and 75.1% respectively) were only
small fractions of the ones recorded during the three-month baseline period,
indicating a dramatic decline in dolphin usage of this survey area as well
during the present impact phase period (Table 3.7).
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 ¡V Nov
2011)
Monitoring Period
|
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 ¡Ó 5.85
|
44.66 ¡Ó 29.85
|
December 2012-February 2013
(Impact)
|
8.36 ¡Ó 5.03
|
35.90 ¡Ó 23.10
|
March-May
2013 (Impact)
|
7.75 ¡Ó 3.96*
|
24.23
¡Ó 18.05*
|
June-August 2013 (Impact)
|
6.56 ¡Ó 3.68
|
27.00 ¡Ó 18.71
|
September-November 2013 (Impact)
|
8.04 ¡Ó 1.10
|
32.48 ¡Ó 26.51
|
December 2013-February 2014
(Impact)
|
8.21 ¡Ó 2.21
|
32.58 ¡Ó 11.21
|
March-May
2014 (Impact)
|
6.51
¡Ó 3.34*
|
19.14
¡Ó 7.19*
|
June-August 2014 (Impact)
|
4.74 ¡Ó 3.84
|
17.52 ¡Ó 15.12
|
September-November 2014 (Impact)
|
5.10 ¡Ó 4.40
|
20.52 ¡Ó 15.10
|
December 2014-February 2015
(Impact)
|
2.91 ¡Ó 2.69
|
11.27 ¡Ó 15.19
|
March-May
2015 (Impact)
|
0.47
¡Ó 0.73*
|
2.36
¡Ó 4.07*
|
June-August 2015 (Impact)
|
2.53 ¡Ó 3.20
|
9.21 ¡Ó 11.57
|
September-November 2015 (Impact)
|
3.94 ¡Ó 1.57
|
21.05 ¡Ó 17.19
|
December 2015-February 2016
(Impact)
|
2.64 ¡Ó 1.52
|
10.98 ¡Ó 3.81
|
March-May
2016 (Impact)
|
0.98
¡Ó 1.10*
|
4.78
¡Ó 6.85*
|
June-August 2016 (Impact)
|
1.72 ¡Ó 2.17
|
7.48 ¡Ó 10.98
|
September-November 2016 (Impact)
|
2.86 ¡Ó 1.98
|
10.89 ¡Ó 10.98
|
December 2016-February 2017
(Impact)
|
3.80 ¡Ó 3.79
|
14.52 ¡Ó 17.21
|
March-May
2017 (Impact)
|
0.93
¡Ó 1.03*
|
5.25
¡Ó 9.53*
|
June-August 2017 (Impact)
|
2.20 ¡Ó 2.88
|
6.58 ¡Ó 8.12
|
September-November 2017 (Impact)
|
3.12 ¡Ó 1.91
|
10.35 ¡Ó 9.66
|
December 2017-February 2018 (Impact)
|
4.75 ¡Ó 2.26
|
15.73 ¡Ó 15.94
|
March-May 2018 (Impact)
|
2.88 ¡Ó 4.81*
|
11.12 ¡Ó 22.46*
|
|
Notes:
1) 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.
2) ¡Ó denotes
the standard deviation of the average encounter rates.
3) The encounter rates in spring months were in
blue and marked with asterisk.
3.5.23 Notably,
when comparing the quarterly periods in spring months, the one in 2018 was
actually noticeably higher than the ones in the previous three years of
2015-17, while it was lower than the ones in 2013 and 2014. There appeared to be a rebound in
dolphin occurrence in NWL waters during spring months in 2018, and it remained
to be seen whether such rebound would be persistent in upcoming spring quarters
and other quarters throughout the year.
Such temporal trend should be closely monitored in the upcoming
monitoring quarters as the construction activities of HZMB works continue to
diminish in coming months.
3.5.24
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).
3.5.25
For the
comparison between the baseline period and the present quarter (22nd
quarter of the impact phase being assessed), the p-values for the differences
in average dolphin encounter rates of STG and ANI were 0.0095 and 0.0390
respectively. If the alpha value is
set at 0.05, significant differences were detected between the baseline and
present quarters in both the average dolphin encounter rates of STG and ANI.
3.5.26
For the
comparison between the baseline period and the cumulative quarters in impact
phase (i.e. the first 22 quarters of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.000000 and 0.000000 respectively.
Even if the alpha value is set at 0.00001, significant differences were
still detected in both the average dolphin encounter rates of STG and ANI (i.e.
between the two periods and the locations).
3.5.27
As indicated in both dolphin distribution patterns and encounter
rates, dolphin usage has been significantly reduced in both NEL and NWL survey
areas during the present quarterly period when compared to the baseline period,
and such low occurrence of dolphins has also been consistently documented in
previous quarters of the past few years.
3.5.28
The significant decline in dolphin usage of North
Lantau region raises serious concern, as the timing of the decline in dolphin
usage in North Lantau waters coincided well with the construction schedule of
the HZMB-related projects (Hung 2017). Apparently, there was little sign of recovery
of dolphin usage even though almost all marine works associated with the HZMB
construction have been completed.
Group
Size
3.5.29
Group
size of Chinese White Dolphins ranged from to twelve individuals per group in North Lantau region during March to May 2018. 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 (Mar ¡V May 2018) and
Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average Dolphin Group Size
|
Reporting Period
|
Baseline Monitoring Period
|
Overall
|
3.33 ¡Ó 3.39 (n = 9)
|
3.72 ¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n
= 17)
|
Northwest Lantau
|
3.33 ¡Ó 3.39 (n = 9)
|
3.92 ¡Ó 3.40 (n = 49)
|
Note:
1) ¡Ó denotes the standard deviation of the
average group size.
3.5.30 The average dolphin group size in NWL waters
during March to May 2018 was slightly lower than the one recorded during the
three-month baseline period, but it should also be noted that the sample size
of nine dolphin groups in the present quarter was very small when compared to
the 66 groups sighted during the baseline period (Table 3.8).
3.5.31 Notably, with the exception of a large group
of twelve animals, the other eight dolphin groups were composed of 1-4
individuals only (Annex II of Appendix J).
3.5.32
Distribution
of the lone larger dolphin group with 12 individuals during the present quarter
is shown Figure 3 of Appendix J, with comparison to the one in baseline
period. That
large dolphin group sighted in the present quarter was located at the western
territory border between Sha Chau and Lung Kwu Chau (Figure 3 of
Appendix J). Such
distribution pattern was very different from the baseline period, when the
larger dolphin groups were frequently sighted and evenly distributed in NWL
waters, and a few were also sighted in NEL waters (Figure 3 of
Appendix J).
Habitat Use
3.5.33
From March to
May 2018, the grids that recorded moderately high to high dolphin densities
were all located to the northeast of Lung Kwu Chau and west of Sha Chau (Figures 4a and 4b of Appendix J). The rest of the grids that recorded dolphin occurrence were low in
densities, and scattered near Lung Kwu Chau and at the mouth of Deep Bay (Figures 4a and 4b of Appendix J).
3.5.34
Notably, all grids near HKLR03/HKBCF reclamation
sites as well as TMCLKL /HKLR09
alignments did not record any presence of dolphins at all during on-effort
search in the present quarterly period (Figures 4a and 4b of Appendix J).
3.5.35 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 should be
examined when more
survey effort for each grid is collected throughout the impact phase monitoring programme.
3.5.36
When compared with the habitat use patterns during
the baseline period, dolphin usage in NEL and NWL has drastically diminished in
both areas during the present impact monitoring period (Figure 5 of
Appendix J). During the baseline period, many grids between Siu
Mo To and Shum Shui Kok in NEL recorded moderately high to high dolphin
densities, which was in stark contrast to the complete absence of dolphins
there during the present impact phase period (Figure 5 of
Appendix J).
3.5.37
The density patterns were also drastically
different in NWL between the baseline and impact phase monitoring periods, with
high dolphin usage recorded throughout the area, especially 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. In contrast, only several grids with
moderately high to high dolphin densities were located within Sha Chau and Lung
Kwu Chau Marine Park during the present impact phase period (Figure 5 of
Appendix J).
Mother-calf Pairs
3.5.38
During the present quarterly period, no young calf was sighted at all among the nine
groups of dolphins.
Activities and Associations with Fishing Boats
3.5.39
Only one of the nine dolphin groups were engaged in
feeding activity, while no group was engaged in socializing, traveling or
milling/resting activity during the
three-month study period.
3.5.40 The
percentages of sightings associated with feeding activity (11.1%) was very
similar to the one recorded during the baseline period (11.6%). However, it should be noted the sample
sizes on total numbers of dolphin sightings were very different between the two
periods.
3.5.41 Distribution
of dolphins engaged in various activities during the present three-month period and
baseline period is shown in
(Figure 6 of Appendix J). The only dolphin group engaged in feeding activity
was sighted to the east of Lung Kwu Chau (Figure 6 of Appendix J). When compared to the baseline period, distribution of various dolphin
activities during the present impact phase monitoring period was very different
with a much more restricted area of occurrences (Figure 6 of
Appendix J).
3.5.42 Notably,
none of the dolphin groups was found to be associated with any operating
fishing vessel during the present impact phase period.
Summary Photo-identification works
3.5.43
From March
to May 2018, over 1,000 digital photographs of Chinese White Dolphins were
taken during the impact phase monitoring surveys for the photo-identification work.
3.5.44
In total, 14 individuals sighted 16 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 re-sightings were made in NWL.
Only two individuals (NL182 and NL226) were re-sighted twice, while the other
12 individuals were re-sighted only once during the three-month period (Annex III of Appendix J).
3.5.45
Notably, five of these 14 individuals (i.e. CH34,
NL136, NL182, NL261 and NL286) were also sighted in Northwest
Lantau waters during the HKBCF monitoring surveys under the same
three-month period. Moreover, two
individuals (NL269 and WL179) were also sighted in West Lantau waters during
the HKLR09 monitoring surveys from March to May 2018, showing their extensive
movements across different survey areas.
Individual range use
3.5.46
Ranging
patterns of the 14 individuals identified during the three-month study period
were determined by fixed kernel method, and are shown in Annex V of Appendix J.
3.5.47
All
identified dolphins sighted in the present quarter were utilizing NWL waters
only, but have completely avoided 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 the baseline period.
3.5.48
On the
other hand, there were several individuals (i.e. WL124, WL145 and WL179) that
have consistently utilized WL waters in the past, but have extended their range
use to NWL waters during the present quarter.
3.5.49
In the
upcoming quarters, individual range use and movements should be continuously
monitored to examine whether there has been any consistent shifts of individual
home ranges from North Lantau to West or Southwest Lantau and vice versa, as
such shift could possibly be related to the HZMB-related construction works (see Hung 2017).
Action Level / Limit Level Exceedance
3.5.50 There was one Limit Level exceedance of dolphin monitoring for the
quarterly monitoring data (between March 2018 ¡V May 2018).
According to the contractor¡¦s information, the marine activities undertaken for
HKLR03 during the quarter of March 2018 ¡V May 2018 included seawall construction, box culvert construction, road and drainage
construction, road and drainage works.
3.5.51
There is no evidence
showing the current LL non-compliance directly related to the construction
works of HKLR03 (where the amounts of working vessels for HKLR03 have been
decreasing), 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 (CWD).
In addition, the contractor will implement proactive mitigation measures
such as avoiding anchoring at Marine Department¡¦s designated anchorage site ¡V
Sham Shui Kok Anchorage (near Brothers Island) as far as practicable.
3.5.52
According to Monitoring
of Chinese White Dolphins in Southwest Lantau Waters ¡V Fourth Quarterly Report
(December 2015 to February 2016) which is available on ENPO¡¦s website, with
their primary ranges centered in North and West Lantau waters, some individuals
showed apparent range shifts or extensions to Southwest Lantau waters in
2015-16. For example, three
individual dolphins (NL120, WL46 and WL221) indicated obvious shifts in their
range use from NWL to West Lantau (WL) and Southwest Lantau (SWL) waters.
Moreover, many individuals (e.g. NL212, NL260, WL200, SL55, WL232, WL237 and
WL265) have extended their ranges from WL waters to SWL waters. It remains to be seen whether some of
these individuals have permanently shifted their ranges away from their primary
ranges in North Lantau, or begin to spend more times in SWL waters as part of
their ranges.
3.5.53 ENPO updated that the Hong Kong-Zhuhai-Macao Bridge Authority (HZMBA) for
the Mainland section of Hong Kong-Zhuhai-Macao Bridge (HZMB) has commenced an
interim survey on fisheries resources and CWD in the Mainland waters. ENPO
presented the preliminary findings of the HZMBA interim survey on CWD sighting
and photo-identification works which provide solid evidence that some CWD that
were previously more often sighted in HK waters have expanded their ranges into
the Mainland waters, and some with reduced usage in HK waters. These
preliminary data were mentioned in Monitoring of Chinese White Dolphins in
Southwest Lantau Waters ¡V Fourth Quarterly Report (December 2015 to February
2016) which is available on ENPO¡¦s website.
3.5.54 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).
3.5.55 For the comparison between the baseline period and the present quarter
(22nd quarter of the impact phase being assessed), the p-values for the
differences in average dolphin encounter rates of STG and ANI were 0.0095 and
0.0390 respectively. If the alpha
value is set at 0.05, significant differences were detected between the
baseline and present quarters in both the average dolphin encounter rates of
STG and ANI.
3.5.56 For comparison between the baseline period and the cumulative quarters in
impact phase (i.e. first 22 quarters of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.000000 and 0.000000 respectively.
Even if the alpha value is set at 0.00001, significant differences were
still detected in both the average dolphin encounter rates of STG and ANI (i.e.
between the two periods and the locations).
3.5.57
The AFCD monitoring data
during March to May 2018 has been reviewed by the dolphin specialist. During the same quarter, no dolphin was
sighted from 55.50 km of survey effort on primary lines in NEL, while only two
groups of two dolphins were sighted from 52.60 km of survey effort on primary
lines in NWL. This review has confirmed that the low occurrence of dolphins
reported by the HKLR03 monitoring surveys in spring 2018 in NEL and NWL survey
area is accurate.
3.5.58 All dolphin protective measures are fully and properly implemented in
accordance with the EM&A Manual. According to the MarineTravel Route Plan,
the travelling speed of vessels must not exceed 5 knots when crossing the edge
of the proposed marine park. 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. Also, it is recommended to complete the
marine works of the Contract as soon as possible so as to reduce the overall
duration of impacts and allow the dolphins population to recover as early as possible.
3.5.59
A meeting was held on 4
September 2018 with attendance of representative of ENPO, Resident Site Staff
(RSS), Environmental Team (ET) and dolphin specialist for Contract Nos.
HY/2013/01, HY/2011/03, HY/2012/07, HY/2012/08. The discussion/ recommendation
as raised in 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
The dolphin specialists
of the projects confirmed that the CWD sighting around the North of Sha Chau
and Lung Kwu Chau Marine Park (SCLKCMP) has significantly decreased, and it was
likely related to the re-routing of high speed ferry (HSF) from Skypier.
3.5.62
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.
3.5.63
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.
3.5.64
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.
3.5.65
HyD updated that the
draft map of the proposed Brothers Marine Park (BMP) was gazetted in February
2016. ENPO updated that the BMP was approved by the Chief Executive in the
Executive Council in August 2016. The ETs were reminded to update the BMP
boundary in the Regular Marine Travel Route (RMTR) Plan. The BMP was designated
on 30 December 2016.
It was suggested that the protection measures (e.g. speed limit control) for
the approved BMP shall be brought forward so as to provide a better habitat for
dolphin recovery. It was noted that under the latest RMTR Plan, the contractors
have committed to reduce the vessel speed in BMP.
3.5.66
The marine travel route
will shift along the edge of Brother Marine Park as much as practical under the
RMTR Plan. It was noted that even though marine vessels may moor within the
mooring site of BMP, commercial activities including loading / unloading /
transshipment are not allowed except a permit is obtained. The HZMB works vessels
were recommended to avoid the BMP.
3.5.67
It was remined that
starting from January 2016, HSF from the SkyPier will be re-routed north to the
northern edged of the Sha Chau and Lung Kwu Chau Marine Park which currently
has the highest density of CWD in the NWL. While the HSF will reduce speed to
15 knots, the associated disturbance may still affect CWD in the area. It was
implied that the CWDs in the area shall be closely followed.
3.5.68
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 18 March 2018. The mudflat surface levels at the four established
monitoring stations and the corresponding XYZ HK1980 GRID coordinates are
presented in Table 3.9 and Table 3.10.
Table 3.9 Measured
Mudflat Surface Level Results
|
Baseline Monitoring
(September 2012)
|
Impact Monitoring
(March 2018)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.162
|
816678.744
|
1.117
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.253
|
815831.503
|
0.986
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.564
|
815953.329
|
1.479
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.435
|
816151.339
|
1.099
|
Table 3.10 Comparison
of Measurement
|
Comparison of measurement
|
Remarks and Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
-0.023
|
-0.011
|
0.231
|
Level continuously
increased
|
S2
|
-0.015
|
0.040
|
0.176
|
Level continuously increased
|
S3
|
-0.040
|
0.067
|
0.177
|
Level continuously increased
|
S4
|
-0.011
|
0.040
|
0.217
|
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(N)) as in the
EM&A Manual. The water quality
monitoring location (SR3(N)) is shown in Figure 2.1.
3.6.4 Impact
water quality monitoring in San Tau (monitoring station SR3) was conducted in
March 2018. The monitoring parameters included dissolved oxygen (DO), turbidity
and suspended solids (SS).
3.6.5 The Impact monitoring result for SR3(N) were extracted and summarised
below:
Table 3.11 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)
|
02-Mar-18
|
8.8
|
4.8
|
4.5
|
8.4
|
4.1
|
5.6
|
05-Mar-18
|
8.2
|
6.8
|
6.5
|
--
|
--
|
--
|
07-Mar-18
|
7.6
|
5.5
|
7.1
|
7.7
|
6.8
|
9.3
|
09-Mar-18
|
7.1
|
5.4
|
7.4
|
7.2
|
6.1
|
7.0
|
12-Mar-18
|
7.5
|
3.0
|
5.1
|
7.9
|
3.7
|
6.3
|
14-Mar-18
|
8.5
|
5.3
|
8.9
|
8.4
|
6.8
|
10.9
|
16-Mar-18
|
8.3
|
6.7
|
9.4
|
8.4
|
6.0
|
7.0
|
19-Mar-18
|
7.3
|
8.5
|
8.6
|
7.4
|
9.8
|
11.2
|
21-Mar-18
|
7.0
|
10.4
|
10.2
|
7.3
|
16.7
|
27.2
|
23-Mar-18
|
7.3
|
7.9
|
8.4
|
7.4
|
10.3
|
13.6
|
26-Mar-18
|
6.9
|
6.2
|
4.4
|
6.9
|
8.2
|
5.3
|
28-Mar-18
|
7.1
|
6.7
|
11.5
|
7.8
|
8.8
|
5.1
|
30-Mar-18
|
7.3
|
6.9
|
13.8
|
7.0
|
15.0
|
14.8
|
Average
|
7.6
|
6.5
|
8.1
|
7.7
|
8.5
|
10.3
|
Remark: Due to foggy
weather and low visibility, water quality monitoring at station SR3(N) during
flood tide on 5 March 2018 were cancelled.
|
Mudflat
Ecology Monitoring
Sampling
Zone
3.6.6 In
order to collect baseline information of mudflats in the study site, the
study site was divided into three sampling zones (labeled as TC1, TC2, TC3) in
Tung Chung Bay and one zone in San Tau (labeled as ST) (Figure 2.1 of Appendix O).
The horizontal shoreline of sampling zones TC1, TC2, TC3 and ST were about 250
m, 300 m, 300 m and 250 m respectively (Figure
2.2 of Appendix O). Survey of horseshoe crabs, seagrass beds and intertidal
communities were conducted in every sampling zone. The present survey was
conducted in March 2018 (totally 6 sampling days between 3rd and 21st
March 2018).
3.6.7
Since
the field survey of Jun. 2016, increasing number of trashes and even big
trashes (Figure 2.3 of Appendix O)
were found in every sampling zone. It raised a concern about the solid waste
dumping and current-driven waste issues in Tung Chung Wan. Respective measures
(e.g. manual clean-up) should be implemented by responsible units.
3.6.8
Similar to previous years, large scaled
recruitment of filamentious algae was observed at high shore location in TC3
and ST (Figure 2.4 of Appendix O).
The algae had covered significant area of mudflat that might affect the survey
of horseshoe crab and seagrass
Horseshoe
Crabs
3.6.9
Active search method was conducted for horseshoe
crab monitoring by two experienced surveyors in every sampling zone. During the
search period, any accessible and potential area would be investigated for any
horseshoe crab individuals within 2-3 hours of low tide period (tidal level
below 1.2 m above Chart Datum (C.D.)). Once a horseshoe crab individual was
found, the species was identified referencing to Li (2008). The prosomal width,
inhabiting substratum and respective GPS coordinate were recorded. A
photographic record was taken for future investigation. Any grouping
behavior of individuals, if found, was recorded. The horseshoe crab surveys
were conducted on 14th (for TC3 and ST) and 21st (for TC1
and TC2) March 2018. The weather was generally warm and humid on both field
days without rainfall.
3.6.10
In Jun.
2017, a big horseshoe crab was tangled by a trash gill net in ST mudflat
(Figure 2.3 of Appendix O). It was released to sea once after photo
recording. The horseshoe crab of such size should be inhabitating sub-tidal
environment while it forages on intertidal shore occasionally during high tide
period. If it is tangled by the trash net for few days, it may die due to
starvation or overheat during low tide period. These trash gill nets are
definitely ¡¥fatal trap¡¦ for the horseshoe crabs and other marine life. Manual
clean-up should be implemented as soon as possible by responsible units.
Seagrass
Beds
3.6.11
Active
search method was conducted for seagrass bed monitoring by two experienced
surveyors in every sampling zone. During the search period, any accessible and
potential area would be investigated for any seagrass beds within 2-3 hours of
low tide period. Once seagrass bed was found, the species, estimated area,
estimated coverage percentage and respective GPS coordinates were recorded. The
seagrass beds surveys were conducted on 14th (for TC3 and ST) and 21st
(for TC1 and TC2) March 2018. The weather was generally warm and humid on both
field days without rainfall.
Intertidal Soft Shore Communities
3.6.12 The intertidal
soft shore community surveys were conducted in low tide period on 3rd
(for TC3), 4th (for TC1), 11th (for TC2) and 17th
(for ST) March 2018. In every sampling zone, three 100m horizontal transect
lines were laid at high tidal level (H: 2.0
m above C.D.), mid tidal level (M: 1.5
m above C.D.) and low tidal level (L: 1.0
m above C.D.). Along every horizontal transect
line, ten random quadrats (0.5 m x 0.5 m) were placed.
3.6.13
Inside a quadrat, any visible epifauna were
collected and were in-situ identified to the lowest practical taxonomical
resolution. Whenever possible a hand core sample (10 cm internal diameter ´ 20 cm depth) of sediments was collected in the
quadrat. The core sample was gently washed through a sieve of mesh size 2.0 mm
in-situ. Any visible infauna were collected and identified. Finally the top 5
cm surface sediments was dug for visible infauna in the quadrat regardless of
hand core sample was taken.
3.6.14
All
collected fauna were released after recording except some tiny individuals that
are too small to be identified on site. These tiny individuals were taken to
laboratory for identification under dissecting microscope.
3.6.15
The taxonomic classification was conducted in
accordance to the following references: Polychaetes: Fauchald (1977), Yang and
Sun (1988); Arthropods: Dai and Yang (1991), Dong (1991); Mollusks: Chan and
Caley (2003), Qi (2004).
Data
Analysis
3.6.16 Data
collected from direct search and core sampling was pooled in every quadrat for
data analysis. Shannon-Weaver Diversity Index (H¡¦) and Pielou¡¦s Species Evenness (J) were calculated for every quadrat using the formulae below,
H¡¦= -£U ( Ni / N ) ln ( Ni / N ) (Shannon and Weaver,
1963)
J = H¡¦ /
ln S, (Pielou, 1966)
where
S is the total number of species in the sample, N is the total number of
individuals, and Ni is the number of individuals of the ith species
Mudflat
Ecology Monitoring Results and Conclusion
Horseshoe
Crabs
3.6.17 In the present survey, two
species of horseshoe crab Carcinoscorpius rotundicauda
(total 31 ind.) and Tachypleus tridentatus (total 44 ind.) were recorded. The recorded
individuals were mainly distributed along the shoreline from TC3 to ST.
Grouping of 2-9 individuals was usually observed on similar substratum (fine sand or
soft mud, slightly submerged). Photo records were shown in Figure 3.1 of Appendix
O while the complete
survey records were listed in Annex II
of Appendix O.
3.6.18
Table 3.1 of Appendix
O summarizes the survey results of
horseshoe crab in the present survey. For
Carcinoscorpius rotundicauda, one individual was
found in TC1 (prosomal width: 41.21 mm) only resulting in very low search
record (0.3 ind.
hr-1 person-1). In
TC3, there was low-moderate number of individuals (22 ind.) with average body
size 55.27 mm (prosomal width ranged 26.63-93.88 mm). In ST, few
individuals were found (8 ind.) with average body size 55.22 mm (35.18-66.75 mm). Both TC3 and ST were low in
search record (1.3-3.7
ind. hr-1 person-1).
3.6.19 Similar survey results were found for Tachypleus tridentatus. One individual was
found in TC1 (prosomal width: 39.61 mm) only resulting in very low search
record (0.3 ind.
hr-1 person-1). In
TC3, there was low-moderate number of individuals (31 ind.) with average body size
55.83 mm (prosomal width ranged 38.90-85.36 mm). In ST, few
individuals were found (12 ind.) with average body size 56.71 mm (39.63-87.61 mm). Both TC3 and ST were low in
search record (2.0-5.2
ind. hr-1 person-1).
3.6.20 In the previous
survey of Mar. 2015, there was one important finding that a mating pair of Carcinoscorpius rotundicauda was found
in ST (prosomal width: male 155.1 mm, female 138.2 mm) (Figure 3.2 of Appendix O). It indicated the importance of ST as a
breeding ground of horseshoe crab. In Jun. 2017, mating pairs of Carcinoscorpius rotundicauda were also found in TC2 (male 175.27
mm, female 143.51 mm) and TC3 (male 182.08 mm, female 145.63 mm) (Figure 3.2
of Appendix O). In Dec. 2017 (present survey), one mating pair was
of Carcinoscorpius rotundicauda was
found in TC3 (male 127.80 mm, female 144.61 mm) (Figure 3.2
of Appendix O). These
mating pairs indicated that breeding of horseshoe crab could be possible along
the coast of Tung Chung Wan rather than ST only, as long as suitable substratum
was available. The recorded mating pairs were found nearly burrowing in soft
mud at low tidal level (0.5-1.0 m above C.D.). The smaller male was holding the
opisthosoma (abdomen carapace) of larger female from behind. Moreover, suitable
breeding period was believed in wet season (Mar - Sep.) because tiny
individuals (i.e. newly hatched) were usually recorded in Jun. and Sep. every
year.
3.6.21 In the previous
surveys (Jun. 2016, Jun. -Dec. 2017), there were occasional records of large
individuals of Carcinoscorpius
rotundicauda (prosomal width ranged 114.45- 178.67 mm, either single or in pair) in ST (Figure 3.3 of Appendix O). Based on their
sizes, it indicated that individuals of prosomal width larger than 100 mm would
progress its nursery stage from intertidal habitat to sub-tidal habitat of Tung
Chung Wan. These large individuals might move onto intertidal shore occasionally
during high tide for foraging and breeding. Because they should be inhabiting
sub-tidal habitat most of the time. Their records were excluded from the data
analysis to avoid mixing up with juvenile population living on intertidal
habitat.
3.6.22 No marked individual of horseshoe crab was recorded
in the present survey. Some marked individuals were found in the previous
surveys of Sep. 2013, Mar. 2014 and Sep. 2014. All of them were released
through a conservation programme in charged by Prof. Paul Shin (Department of
Biology and Chemistry, The City University of Hong Kong (CityU)). It was a
re-introduction trial of artificial bred horseshoe crab juvenile at selected
sites. So that the horseshoe crab population might be restored in the natural
habitat. Through a personal conversation with Prof. Shin, about 100 individuals
were released in the sampling zone ST on 20 June 2013. All of them were marked
with color tape and internal chip detected by specific chip sensor. There
should be second round of release between June and September 2014 since new
marked individuals were found in the survey of Sep. 2014.
3.6.23 The artificial bred individuals, if found, would be
excluded from the results of present monitoring programme in order to reflect
the changes of natural population. However, the mark on their prosoma might
have been detached during moulting after a certain period of release. The
artificially released individuals were no longer distinguishable from the
natural population without the specific chip sensor. The survey data collected
would possibly cover both natural population and artificially bred individuals.
Population
difference among the sampling zones
3.6.24
Figures 3.4 and
3.5 of Appendix O show the changes
of number of individuals, mean prosomal width and search record of horseshoe
crabs Carcinoscorpius rotundicauda
and Tachypleus tridentatus
respectively in every sampling zone throughout the monitoring period.
3.6.25
For TC3
and ST, medium to high search records (i.e. number of individuals) of both
species were always found in wet season (Jun. and Sep.). The search record of
ST was higher from Sep. 2012 to Jun. 2014 while it was replaced by TC3 from
Sep. 2014 to Jun. 2015. The search records were similar between two sampling
zones from Sep. 2015 to Jun. 2016. In Sep. 2016, the search record of Carcinoscorpius rotundicauda in ST was
much higher than TC3. From Mar. to Jun. 2017, the search records of both
species were similar again between two sampling zones. It showed a natural
variation of horseshoe crab population in these two zones due to weather
condition and tidal effect. No obvious difference of horseshoe crab population
was noted between TC3 and ST. In Sep. 2017, the search records of both horseshoe
crab species decreased except the Carcinoscorpius
rotundicauda in TC3. The survey results were different from previous
findings that there were usually higher search records in Sep. One possible
reason was that the serial cyclone hit decreased horseshoe crab activity
(totally 4 cyclone records between Jun. and Sep. 2017, to be discussed in
'Seagrass survey' section). In
Sep. 2017 and Mar. 2018 (present survey), higher search records were found in
TC3.
3.6.26
For
TC1, the search record was at low to medium level throughout the monitoring
period. The
change of Carcinoscorpius rotundicauda was
relatively more variable than that of Tachypleus tridentatus. Relatively, the search record was very low
in TC2 (2 ind. in Sep. 2013; 1 ind. in Mar.-Sep. 2014, Mar.-Jun. 2015; 4 ind.
in Sep. 2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016, 1 ind. from Mar.-Sep.
2017).
3.6.27
About the body size, larger individuals of Carcinoscorpius rotundicauda were
usually found in ST and TC1 relative to those in TC3 from
Sep. 2012 to Jun. 2017. But the body size was higher in TC3 and ST followed by
TC1 from Sep. 2017 to Mar. 2018. For Tachypleus
tridentatus, larger individuals were usually found in ST followed by TC3
and TC1 throughout the montioring period.
3.6.28
In
general, it was obvious
that TC3 and ST (western shore of Tung Chung Wan) was an important
nursery ground for horseshoe crab especially newly hatched individuals due to
larger area of suitable substratum (fine sand or soft mud) and less human
disturbance (far from urban district). Relatively, other sampling zones were
not a suitable nursery ground especially TC2. Possible factors were less area
of suitable substratum (especially TC1) and higher human disturbance (TC1 and
TC2: close to urban district and easily accessible). In TC2, large daily
salinity fluctuation was a possible factor either since it was flushed by two
rivers under tidal inundation. The individuals inhabiting TC1 and TC2 were
confined in small foraging area due to limited area of suitable substrata.
Although a mating pair of Carcinoscorpius rotundicauda was once found in TC2, the hatching rate and
survival rate of newly hatched individuals were believed very low.
Seasonal variation of horseshoe crab population
3.6.29 Throughout the
monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures
3.3 and 3.4 of Appendix O). In Dec. 2012, 4
individuals of Carcinoscorpius rotundicauda
and 12 individuals of Tachypleus
tridentatus were found only. In Dec. 2013, no
individual of horseshoe crab was found. In Dec. 2014, 2
individuals of Carcinoscorpius rotundicauda
and 8 individuals of Tachypleus
tridentatus were found only. In Dec. 2015, 2
individuals of Carcinoscorpius rotundicauda, 6
individuals of Tachypleus
tridentatus and one newly hatched, unidentified
individual were found only. The
horseshoe crabs were inactive and burrowed in the sediments during cold weather
(<15 ºC). Similar results of low search record in dry
season were reported in a previous territory-wide survey of horseshoe crab. For
example, the search records in Tung Chung Wan were 0.17 ind. hr-1
person-1 and
0.00 ind. hr-1 person-1 in wet season and dry season respectively
(details see Li, 2008). Relatively the serach records were much higher in Dec.
2016. There were totally 70 individuals of Carcinoscorpius
rotundicauda and 24 individuals of Tachypleus tridentatus in TC3 and ST.
Because the survey was arranged in early December while the weather
was warm with sunlight (~22
¢XC
during dawn according to Hong Kong Observatory database, Chek Lap Kok station
on 5 Dec). In contrast, there was no search record in
TC1 and TC2 because the survey was conducted in mid December with colder and
cloudy weather (~20 ¢XC
during dawn on 19 Dec). The horseshoe crab activity would decrease
gradually with the colder
climate. In Dec. 2017 (present survey), the weather was cold (13-15 ºC during dawn) that very few individuals of both specis
could be found as mentioned above.
3.6.30 From Sep. 2012 to
Dec. 2013, Carcinoscorpius rotundicauda
was a less common species relative to Tachypleus
tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This
species had ever been believed of very low density in ST hence the encounter
rate was very low. Since Mar. 2014, it was found in all sampling zones with
higher abundance in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and spawning of this species had
occurred about 3 years ago along the coastline of Tung Chun Wan. However, these
individuals were still small while their walking trails were inconspicuous.
Hence there was no search record in previous sampling months. Since Mar. 2014,
more individuals were recorded due to larger size and higher activity (i.e.
more conspicuous walking trail).
3.6.31
For Tachypleus
tridentatus, sharp increase of number of individuals was recorded in ST
during the wet season of 2013 (from Mar. to Sep.). According to a personal
conversation with Prof. Shin (CityU), his monitoring team had recorded similar
increase of horseshoe crab population during wet season. It was believed that
the suitable ambient temperature increased its conspicuousness. However similar
pattern was not recorded in the following wet seasons. The number of
individuals increased in Mar. and Jun. 2014 followed by a rapid decline in Sep.
2014. Then the number of individuals fluctuated slightly in TC3 and ST until
Mar. 2017. Apart from natural mortality, migration from nursery soft shore to
subtidal habitat was another possible cause. Since the mean prosomal width of Tachypleus
tridentatus continued to grow and reached about 50 mm since Mar. 2014. Then
it varied slightly between 35-65 mm from Sep. 2014 to Mar. 2017. Most of the individuals
might have reached a suitable size (e.g. prosomal width 50-60 mm) strong enough
to forage in sub-tidal habitat. In Jun. 2017, the number of individuals
increased sharply again in TC3 and ST. Although mating pair of Tachypleus
tridentatus was not found in previous surveys, there should be new round of
spawning in the wet season of 2016. The individuals might have grown to a more
conspicuous size in 2017 accounting for higher search record. In
Sep. 2017 and Mar. 2018 (present survey), moderate numbers of individual were
found in TC3 and ST indicating a stable population size.
3.6.32 Recently, Carcinoscorpius rotundicauda was a more
common horseshoe crab species in Tung Chung Wan. It was recorded in the four
sampling zones while the majority of population located in TC3 and ST. Due to
potential breeding last year, Tachypleus
tridentatus became common again and distributed in TC3 and ST only. Since
TC3 and ST were regarded as important nursery ground for both horseshoe crab
species, box plots of prosomal width of two horseshoe crab species were
constructed to investigate the changes of population in details.
Box plot of horseshoe crab populations in TC3
3.6.33
Figure 3.6 of Appendix O shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius rotundicauda
was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking.
In Mar 2014, the major size (50%
of individual records between upper (top of red box) and lower quartile (bottom
of blue box)) ranged 40-60 mm while only few individuals were found. From Mar.
2014 to Jun. 2017, the median prosomal width (middle line of whole box) and
major size (whole box) decreased after Mar. of every year. It was due to more
small individuals found. It indicated new rounds of spawning. Also there
were slight increasing trends of body size from Jun. to Mar. of next year since
2015. It indicated a stable growth of individuals. Focused on larger juveniles
(upper whisker), the size range was quite variable (prosmal width 60-90 mm)
along the sampling months. Juveniles reaching this size might gradually migrate
to sub-tidal habitats.
3.6.34
For Tachypleus tridentatus, the major size ranged 20-50 mm while the
number of individuals fluctuated from Sep. 2012 to Jun. 2014. Then a slight but
consistent growing trend was observed from Sep. 2014 to Jun. 2015. The prosomal
width increased from 25-35 mm to 35-65 mm. As mentioned, the large individuals
might have reached a suitable size for migrating from the nursery soft shore to
subtidal habitat. It accounted for the declined population in TC3. From Mar. to
Sep. 2016, slight increasing trend of major size was noticed again. From Dec.
2016 to Jun. 2017, similar increasing trend of major size was noted with much
higher number of individuals. It reflected new round of spawning. In Sep. 2017,
the major size decreased while the trend was different from previous two years.
Such decline might be the cause of serial cyclone hit between Jun. and Sep.
2017 (to be discussed in the 'Seagrass survey' section). From Dec. 2017 to Mar.
2018 (present survey), slight increasing trend was noted again. Across
the whole monitoring period, the larger juveniles (upper whisker) usually
reached 60-80 mm in prosomal width, even 90 mm occasionally. Juveniles reaching
this size might gradually migrate to sub-tidal habitats.
Box plot of
horseshoe crab populations in ST
3.6.35
Figure 3.7 of Appendix O shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. From Mar. 2014 to Sep. 2017, the size of major population
decreased and more small individuals (i.e. lower whisker) were recorded after
Jun. of every year. It indicated new round of spawning. Also there were similar
increasing trends of body size from Sep. to Jun. of next year between 2014 and
2017. It indicated a stable growth of individuals. Across the whole monitoring
period, the larger juveniles (i.e. upper whisker) usually ranged 60-80 mm in
prosomal width except one individual (prosomal width 107.04 mm) found in Mar.
2017. It reflected juveniles reaching this size would gradually migrate to
sub-tidal habitats.
3.6.36
For Tachypleus tridentatus, a consistent
growing trend was observed for the major population from Dec. 2012 to Dec. 2014
regardless of change of search record. The prosomal width increased from 15-30 mm to 60-70 mm. As mentioned,
the large juveniles might have reached a suitable size for
migrating from the nursery soft shore to subtidal habitat. From Mar. to Sep.
2015, the size of major population decreased slightly to a prosomal width 40-60
mm. At the same time, the number of individuals decreased gradually. It further
indicated some of large juveniles might have migrated to sub-tidal habitat,
leaving the smaller individuals on shore. There was an overall growth trend. In
Dec. 2015, two big individuals (prosomal width 89.27 mm and 98.89 mm) were
recorded only while it could not represent the major population. In Mar. 2016,
the number of individual was very few in ST that no boxplot could be produced.
In Jun. 2016, the prosomal width of major population ranged 50-70 mm. But it
dropped clearly to 30-40 mm in Sep. 2016 followed by an increase to 40-50 mm in
Dec. 2016, 40-70 mm in Mar. 2017 and 50-60mm in Jun. 2017. Based on overall
higher number of small individuals from Jun. 2016 to Sep. 2017, it indicated
new round of spawning. From Sep. 2017 to Mar. 2018 (present survey), the major
size range increased slightly from 40-50 mm to 45-60 mm indicating a continuous
growth. Throughout the monitoring period, the larger junveniles ranged 60-80 mm
in prosomal width. Juveniles reaching this size would gradually migrate to
sub-tidal habitats.
3.6.37
As a
summary for horseshoe crab populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014
to 2016 while the spawning time should be in spring. There
were consistent, increasing trends of population size in these two sampling
zones. For Tachypleus tridentatus,
small individuals were rarely found in both zones from 2014 to 2015. It
was believed no occurrence of successful spawning. The existing individuals
(that recorded since 2012) grew to a mature size and migrated to sub-tidal
habitat. Hence the number of individuals decreased gradually.
In 2016, new round of spawning was recorded in ST while increasing number of
individuals and body size was noticed.
Impact of the HKLR project
3.6.38
It was the 22nd survey of the EM&A
programme during the construction period. Based on the results, impact of the
HKLR project could not be detected on horseshoe crabs. The population change
was mainly determined by seasonal variation while new rounds of spawning were
observed for both species. In case, abnormal phenomenon (e.g. very few numbers
of horseshoe crab individuals in wet season, large number of dead individuals
on the shore) is found, it would be reported as soon as possible.
Seagrass
Beds
3.6.39
From
Sep. to Mar. 2018 (present survey), no seagrass bed
was recorded in Tung Chung Wan. Extensive area of mudflat, where used to be
covered by seagrass beds, re-exposed along TC3 and ST (Figure 3.8 of Appendix O). In the
previous survey of Jun. 2017, two species of seagrass Halophila ovalis and Zostera
japonica were recorded in TC3 and ST (Figure
3.9 of Appendix O). There was still extensive seagrass area (~17046.5 m2)
of Halophila ovalis along the mudflat
between TC3 and ST at 0.5-2.0 m above C.D.. Another seagrass species Zostera japonica, which was much lower
in vegetation area (~105.4 m2), was co-existing with few patches of Halophila ovalis nearby the mangrove
strand. The disappearance of seagrass beds would be discussed in later
paragraphs.
3.6.40 According to the previous results, majority
of seagrass bed was confined in ST, the temporal change of both seagrass species
were investigated in details:
Temporal variation of seagrass beds
3.6.41
Figure 3.10 of Appendix O shows the changes of estimated total area of
seagrass beds in ST along the sampling months. For Zostera japonica, it
was not recorded in the 1st and 2nd surveys of monitoring
programme. Seasonal recruitment of few small patches (total seagrass area: 10 m2) was found in
Mar. 2013 that grew within the large patch of seagrass
Halophila ovalis. Then the patch size increased and merged
gradually with the warmer climate from Mar. to Jun. 2013 (15 m2).
However the patch size decreased and remained similar from Sep. 2013 (4 m2)
to Mar. 2014 (3 m2). In Jun. 2014, the patch size increased
obviously again (41 m2) with warmer climate followed by a decrease
between Sep. 2014 (2 m2) and Dec. 2014 (5 m2). From Mar.
to Jun. 2015, the patch size increased sharply again (90 m2). It
might be due to the disappearance of the originally dominant seagrass Halophila ovalis
resulting in less competition for substratum and nutrients. From Sep.2015 to
Jun.2016, it was found coexisting with seagrass Halophila
ovalis with steady increasing patch size (from 44 m2 to 115 m2)
and variable coverage. In Sep. 2016, the patch size decreased again to (38 m2)
followed by an increase to a horizontal strand (105.4 m2) in Jun. 2017 (present survey). And it was no
longer co-existing with Halophila
ovalis. Between Sep. 2014 and Jun. 2017, an
increasing trend was noticed from Sep. to Jun. of next year followed by a rapid
decline in Sep. of next year. It was possibly the causes of heat stress,
typhoon and stronger grazing pressure during wet season. In Sep. to Mar. 2018
(present survey), no seagrass patch of Zostera
japonica was found.
3.6.42 For Halophila ovalis,
it was recorded as 3-4 medium to large patches (area 18.9-251.7 m2;
vegetation coverage 50-80%) beside the mangrove vegetation at tidal level 2 m
above C.D. in Sep. 2012 (first survey). The total seagrass bed area grew steadily from 332.3 m2 in
Sep. 2012 to 727.4 m2 in Dec. 2013. Flowers were observed in the
largest patch during its flowering period. In Mar. 2014, 31 small to medium patches were
newly recorded (variable area 1-72 m2 per patch, vegetation coverage
40-80% per patch) in lower tidal zone between 1.0 and 1.5 m above C.D. The
total seagrass area increased further to 1350 m2. In Jun. 2014,
these small and medium patches grew and extended to each other. These patches
were no longer distinguishable and were covering a significant mudflat area of
ST. It was generally grouped into 4 large patches (1116 ¡V 2443 m2)
of seagrass beds characterized of patchy distribution, variable vegetable
coverage (40-80%) and smaller leaves. The total seagrass bed area increased
sharply to 7629 m2. In Sep. 2014, the total seagrass area declined
sharply to 1111 m2. There were only 3-4 small to large patches
(6-253 m2) at high tidal level and 1 large patch at low tidal level
(786 m2). Typhoon or strong water
current was a possible cause
(Fong, 1998). In Sep. 2014, there were two tropical cyclone records in Hong
Kong (7th-8th Sep.: no cyclone name, maximum signal
number 1; 14th-17th Sep.: Kalmaegi, maximum signal number
8SE) before the seagrass survey dated 21st Sep. 2014. The strong
water current caused by the cyclone, Kalmaegi especially, might have given
damage to the seagrass beds. In addition, natural heat stress and grazing force
were other possible causes reducing seagrass beds area. Besides, very small
patches of Halophila ovalis could be found in other mud flat area in
addition to the recorded patches. But it was hardly distinguished due to very
low coverage (10-20%) and small leaves.
3.6.43
In Dec. 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.10 of Appendix O shows the
difference of the original seagrass beds area nearby the mangrove vegetation at
high tidal level between Jun. 2014 and Dec. 2014. Such rapid loss would not be seasonal
phenomenon because the seagrass beds at higher tidal level (2.0 m above C.D.)
were present and normal in December 2012 and 2013. According to Fong (1998),
similar incident had occurred in ST in the past. The original seagrass area had
declined significantly during the commencement of the construction and
reclamation works for the international airport at Chek Lap Kok in 1992. The
seagrass almost disappeared in 1995 and recovered gradually after the
completion of reclamation works. Moreover, incident of rapid loss of seagrass
area was also recorded in another intertidal mudflat in Lai Chi Wo in 1998 with
unknown reason. Hence Halophila ovalis
was regarded as a short-lived and r-strategy
seagrass that could colonize areas in short period but disappears quickly under
unfavourable conditions (Fong, 1998).
Unfavourable
conditions to seagrass Halophila ovalis
3.6.44
Typhoon or strong
water current was suggested as one unfavourable condition to Halophila ovalis (Fong, 1998). As
mentioned above, there were two tropical cyclone records in Hong Kong in Sep.
2014. The strong water current caused by the cyclones might have given damage
to the seagrass beds.
3.6.45 Prolonged light deprivation due to turbid water
would be another unfavouable condition. Previous studies reported that Halophila
ovalis had little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999).
Hence the seagrass bed of this species was susceptible to temporary light
deprivation events such as flooding river runoff (Longstaff and Dennison,
1999).
3.6.46 In order to
investigate any deterioration of water quality (e.g. more turbid) in ST, the
water quality measurement results at two closest monitoring stations SR3 and
IS5 of the EM&A programme were obtained from the water quality monitoring
team. Based on the results from June to December 2014, the overall water
quality was in normal fluctuation except there was one exceedance of suspended
solids (SS) at both stations in September. On 10th Sep., 2014, the
SS concentrations measured during mid-ebb tide at stations SR3 (27.5 mg/L) and
IS5 (34.5 mg/L) exceeded the Action Level (≤23.5 mg/L and 120% of upstream
control station¡¦s reading) and Limit Level (≤34.4 mg/L and 130% of upstream
control station¡¦s reading) respectively. The turbidity readings at SR3 and IS5
reached 24.8-25.3 NTU and 22.3-22.5 NTU respectively. The temporary turbid
water should not be caused by the runoff from upstream rivers. Because there
was no rain or slight rain from 1st to 10th Sep. 2014
(daily total rainfall at the Hong Kong International Airport: 0-2.1 mm;
extracted from the climatological data of Hong Kong Observatory). The effect of
upstream runoff on water quality should be neglectable in that period. Moreover
the exceedance of water quality was considered unlikely to be related to the
contract works of HKLR according to the ¡¥Notifications of Environmental Quality
Limits Exceedances¡¦ provided by the respective environmental team. The
respective construction of seawall and stone column works, which possibly
caused turbid water, were carried out within silt curtain as recommended in the
EIA report. Moreover there was no leakage of turbid water, abnormity or
malpractice recorded during water sampling. In general, the exceedance of
suspended solids concentration was considered to be attributed to other
external factors, rather than the contract works.
3.6.47 Based on the
weather condition and water quality results in ST,
the co-occurrence of cyclone hit and turbid waters in Sep. 2014 might have
combined the adverse effects on Halophila
ovalis that leaded to disappearance of this
short-lived and r-strategy seagrass
species. Fortunately Halophila ovalis was a fast-growing species (Vermaat et al.,
1995). Previous studies showed that the seagrass bed could be recovered to the
original sizes in 2 months through vegetative propagation after experimental
clearance (Supanwanid, 1996). Moreover it was reported to recover rapidly in
less than 20 days after dugong herbivory (Nakaoka and Aioi, 1999). As
mentioned, the disappeared seagrass in ST in 1995 could recover gradually after
the completion of reclamation works for international airport (Fong, 1998). The
seagrass beds of Halophila ovalis might recolonize the mudflat of ST through
seed reproduction as long as there was no unfavourable condition in the coming months.
Recolonization
of seagrass beds
3.6.48
Figure
3.10 of Appendix
O shows
the recolonization of
seagrass bed area in ST from Dec. 2014 to Jun. 2017. From Mar.
to Jun. 2015, 2-3 small patches of Halophila
ovalis were newly found coinhabiting with another seagrass species Zostera japonica. But its total patch area was
still very low relative to the previous records. The recolonization rate was
low while cold weather and insufficient sunlight were possible factors between
Dec. 2014 and Mar. 2015. Moreover, it would need to compete with seagrass Zostera japonica for substratum and nutrient.
Since Zostera japonica had extended and had covered the original
seagrass bed of Halophila ovalis at
certain degree. From Jun. 2015 to Mar. 2016, the total seagrass area of Halophila ovalis had increased rapidly
from 6.8 m2 to 230.63 m2. It had
recolonized its original patch locations and covered Zostera japonica. In Jun. 2016, the total seagrass area
increased sharply to 4707.3 m2. Similar to the
previous records of Mar to Jun. 2014, the original patch area increased further
to a horizontally long strand. Another large seagrass beds colonized the lower tidal zone (1.0-1.5 m
above C.D.). In Sep. 2016, this patch extended much and covered significant
soft mud area of ST, resulting in sharp increase of total area (24245 m2).
It indicated the second extensive colonization of this r-strategy seagrass. In Dec. 2016, this
extensive seagrass patch decreased in size and had separated into few, undistinguishable patches. Moreover, the
horizontal strand nearby the mangrove vegetation decreased in size (Fig. 3.10).
The total seagrass bed decreased to 12550 m2. From Mar. to Jun.
2017, the seagrass bed area remained generally stable (12438-17046.5 m2)
but the vegetation coverage fluctuated (20-50% in Mar. 2017 to 80-100% in Jun.
2017).
Re-disappearance
of seagrass bed
3.6.49
In Sep 2017, the whole seagrass bed of Halophila ovalis disappeared again along
the shore of TC3 and ST (Figure 3.11 of Appendix O).
It was similar to the case between Sep. and Dec. 2014. As mentioned, strong
water current (e.g. cyclone) or deteriorated water quality (e.g. high
turbidity) were the possible causes.
3.6.50
Between the survey periods of Jun. and Sep.
2017, there were four tropical cyclone records in Hong Kong (Merbok in 12-13th,
Jun.; Roke in 23rd, Jul.; Hato in 22-23rd, Aug.; Pakhar
in 26-27th, Aug.) (online database of Hong Kong Observatory). All of
them reaches signal 8 or above especially Hato (highest signal 10).
3.6.51
According to the water quality monitoring
results (Jul. to Aug. 2017) of the two closest monitoring stations SR3 and I5
of the respective EM&A programme, the overall water quality was in normal
fluctuation. There was one exceedance of suspended solids (SS) at SR3 on 12
Jul. 2017. The SS concentration reached 24.7 mg/L during mid-ebb tide. It
exceeded the Action Level (≤23.5 mg/L) but was far below the Limit Level (≤34.4 mg/L).
Since such exceedance was slight and temporary, its effect to seagrass bed
should be minimal.
3.6.52
Overall, the disappearance of seagrass beds in
ST was believed the cause of serial cyclone hit in Jul and Aug. 2017. Based on
previous findings, the seagrass beds of both species were expected to
recolonize the mudflat as long as the vicinal water quality was normal. The
whole recolonization process (from few, small patches to extensive strand)
would be gradual lasting 1.5 to 2 years. From Dec. 2017 to Mar. 2018, there was
still no recolonization of few, small patches of seagrass at the usual
location. It was different from previous re-colonization (Mar. 2015 - Jun.
2017) that new, small seagrass patches were found within three months. The
results of coming wet season survey (Jun. 2018) would provide a better
understanding about seagrass status.
Impact
of the HKLR project
Intertidal
Soft Shore Communities
3.6.54
Table 3.2 and Figure 3.12 of Appendix O
show the types of substratum along the horizontal transect at every tidal level
in all sampling zones. The relative distribution of different substrata was
estimated by categorizing the substratum types (Gravels & Boulders / Sands
/ Soft mud) of the ten random quadrats along the horizontal transect. The
distribution of substratum types varied among tidal levels and sampling zones:
¡P
In TC1, high percentages of ¡¥Gravels and Boulders¡¦
(80%) were recorded at high and mid tidal levels. Even distribution of ¡¥Soft
mud¡¦ (50%) and ¡¥Gravels and Boulders¡¦ (40%) was recorded at low tidal level.
¡P
In TC2, higher percentages of 'Sands' (50%) and
'Soft mud' (30%) were recorded at high tidal level. There were higher
percentages of 'Sands' (50%) and 'Gravels and Boulders' (40%) at mid tidal
level. At low tidal level, the major substratum type was 'Soft mud' (80%).
¡P
In TC3, high percentages of ¡¥Sands¡¦ (90-100%) were
recorded at high and mid tidal levels. At low tidal level, the major substratum
type was ¡¥Gravels and Boulders¡¦ (90%).
¡P
In ST, ¡¥Gravels and Boulders¡¦ was the main
substratum (100%) at high tidal level. At mid tidal level, there was high
percentage of ¡¥Gravels and Boulders¡¦ (70%) followed by 'Soft mud' (30%). At low
tidal level, the substartum types were mainly ¡¥Soft mud¡¦ (70%) and 'Sands'
(30%).
3.6.55
There
was neither consistent vertical nor horizontal zonation pattern of substratum
type in all sampling zones. Such heterogeneous variation should be caused by
different hydrology (e.g. wave in different direction and intensity) received
by the four sampling zones.
3.6.56
Table 3.3 of Appendix O
lists the total abundance, density and number of taxon of every phylum in this
survey. A total of 14079 individuals were recorded.
Mollusca was clearly the most
abundant phylum (total abundance 13536 ind., density 451 ind. m-2,
relative abundance 96.1 %). The second and third abundant phya
were Arthropoda (421 ind., 14
ind. m-2, 3.0 %) and Annelida (57
ind., 2 ind. m-2, 0.4 %)
respectively. Relatively other phyla were very low in abundances
(density £1
ind. m-2, relative abundance £0.2
%). Moreover, the most diverse phylum was Mollusca
(37 taxa) followed by Arthropoda
(16 taxa) and Annelida (9 taxa). There was 1-3 taxa
recorded only for other phyla. The taxonomic resolution
and complete list of recorded fauna are shown in Annexes IV and V of Appendix O
respectively.
3.6.57
Table 3.4 of Appendix O shows
the number of individual, relative abundance
and density of each phylum in every sampling zone. The
total abundance (2198-5497 ind.) varied among the four sampling zones while the
phyla distributions were similar. In general, Mollusca
was the most dominant phylum (no. of individuals: 2030-5395
ind.; relative abundance 92.4-98.1 %; density 271-719 ind.
m-2). Other phyla were much lower in
number of individuals. Arthropoda (55-144
ind.; 1.4-6.2 %; 7-19 ind. m-2) was the
second abundant phylum. Annelida (9-25 ind.; 0.4-0.8 %; 1-3 ind. m-2)
was the third abundant phylum in TC2, TC3 and ST. Sipuncula
(7 ind.; 0.1 %; 1 ind. m-2)
was the third abundant phylum in TC1 while it was also commonly found in TC2
and TC3 (8-12 ind.; 0.2-0.5 %; 1-2 ind. m-2). Relatively
other phyla were very low in abundance in all sampling zones.
Dominant species in every
sampling zone
3.6.58
Table 3.5 of Appendix O lists
the abundant species (relative abundance >10 %) in
every sampling zone. In the present survey, most of the listed
abundant species were of low to moderate densities (50-250 ind. m-2).
Few listed species of high or very high density (> 250 ind. m-2)
were regarded as dominant species. Other listed species of lower density (<
50 ind. m-2) were regared as common species.
3.6.59
In TC1,
the substratum was mainly ¡¥Gravels and
Boulders¡¦ at high tidal level. It was dominated by gastropod Batillaria
multiformis (644 ind. m-2,
relative abundance 64 %) at very high density followed by gastropod Cerithidea
djadjariensis (207 ind. m-2, 20 %). At mid tidal level
(substratum type ¡¥Gravels and
Boulders¡¦), there were few abundant gastropods Batillaria multiformis
(180 ind. m-2, 30 %), Cerithidea
djadjariensis (117 ind. m-2, 20 %) and Monodonta labio (86 ind.
m-2, 14 %) at low-moderate densities. And the rock oyster Saccostrea
cucullata (118 ind. m-2, 20 %, attached on boulders) was also
abundant. At low tidal level (substratum types 'Soft mud' and ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea cucullata (212
ind. m-2, 36 %) was clearly abundant, attaching on the boulders.
There were also gastropods Monodonta labio (78 ind.
m-2, 13 %), Cerithidea djadjariensis (64 ind. m-2,
11 %) and Batillaria multiformis (56 ind. m-2, 10 %).
3.6.60
In TC2,
the substratum was either
'Sands' and 'Soft mud' at high tidal level.
Gastropod Cerithidea djadjariensis (141 ind. m-2, 44 %) was abundant at moderate density.
Other common fauna included gastropods Batillaria zonalis
(46 ind.
m-2, 14 %), Batillaria multiformis (36 ind. m-2,
11 %) and rock oyster Saccostrea cucullata (40 ind. m-2, 13
%, attached on boulders). At mid tidal level (main substratum types 'Sands' and
'Soft mud'), there was abundant rock oyster Saccostrea cucullata at
modeate density (106 ind. m-2, 36 %) followed by common gastropods Batillaria
zonalis (57 ind. m-2, 19 %) and Monodonta
labio (34 ind. m-2, 12 %). At low tidal
level whose substratum type was mainly soft mud, rock oyster Saccostrea
cucullata was also abudnant (151 ind. m-2, 41 %) followed by
common gastropod Batillaria zonalis (64 ind. m-2,
18 %) and barnacle Balanus amphitrite
(38 ind.
m-2, 10 %, attached on boulders.
3.6.61 In TC3, the major substratum types were mainly ¡¥Sands¡¦ at high
and mid tidal levels. Gastropods Batillaria multiformis (252 ind. m-2, 47 %) and Cerithidea
djadjariensis (204 ind. m-2,
38 %) were both abundant species at high tidal level. At mid tidal level,
gastropod Cerithidea djadjariensis (180 ind. m-2, 47 %) was
found abundant followed by other grastropods Batillaria multiformis (88
ind. m-2, 23 %), Batillaria zonalis (48 ind. m-2,
13 %) and Cerithidea cingulata (39 ind. m-2, 10 %).
At low tidal level (major
substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea cucullata (268
ind. m-2, 40 %) and gastropod Monodonta labio (202 ind. m-2, 30 %) were abundant at moderate densities.
3.6.62
In ST, the
major substratum types were mainly ¡¥Gravels and Boulders¡¦ at high and mid tidal
levels. Gastropod Batillaria multiformis (109 ind. m-2, 27 %), Monodonta labio (84 ind. m-2, 21 %) and rock
oyster Saccostrea cucullata (60 ind. m-2, 15 %, attached on
boulders) were abundant at low-moderate densities followed by common gastropod Batillaria
bornii (45 ind. m-2, 11 %). At mid tidal level, rock
oyster Saccostrea cucullata (110 ind. m-2,
33%) was abundant at moderate density followed by common gastropods Monodonta
labio (40 ind. m-2,
12 %) and Lunella coronata (34 ind. m-2, 10 %). At low tidal level (major substratum type: ¡¥Soft mud¡¦), there were two
common speices including rock
oyster Saccostrea cucullata (43 ind. m-2, 31%) and barnacle Balanus
amphitrite (29 ind. m-2, 21 %).
3.6.63 In general, there was no consistent
zonation pattern of species distribution across all sampling
zones and tidal levels. The species distribution should be determined
by the type of substratum primarily. In general,
gastropods Batillaria multiformis (total number of individuals: 3608 ind., relative abundance 25.6 %), Cerithidea
djadjariensis (2498 ind., 17.7
%), Batillaria zonalis
(713 ind., 5.1 %) and Cerithidea cingulata (580 ind., 4.1 %) were the most commonly occurring species
on sandy and soft mud substrata. Rock
oyster Saccostrea cucullata (2840 ind., 20.2 %), gastropods Monodonta labio (1437 ind., 10.2
%) and Lunella coronata (400 ind., 2.8 %) were commonly occurring species inhabiting gravel and boulders substratum.
Biodiversity
and abundance of soft shore communities
3.6.64
Table 3.6 of
Appendix O shows the
mean values of species number, density, biodiversity
index H¡¦ and
species evenness J of
soft shore communities at every tidal level and in every sampling
zone. As mentioned above, the differences among sampling zones and tidal
levels were determined by the major type of substratum primarily.
3.6.65
Among the sampling
zones, there was no obvious difference of mean
species number, H' and J regardless of tidal levels. The mean
species numbers ranged 9-12 spp. 0.25 m-2 among all sampling zones.
The mean density of TC1 (733 ind. m-2) were higher than TC3 (527
ind. m-2) followed by TC2 and ST (293-325 ind. m-2). The
much higher density of TC1 was mainly accounted by one gastropod species
of high abundance at high tidal level. It leaded to moderate species evenness.
ST was lowest in mean density while the taxa distribution was even. It also
leaded to moderate species evenness. Overall the mean H¡¦ and J were similar, that ranged 1.3-1.7 and 0.6-0.7 respectively among
all sampling zones.
3.6.66
Across the tidal
levels, there were slightly increasing trends of
mean species number and H' from high
to low tidal level in TC1, TC2 and TC3 but vice versa in ST. For the mean
density, there were generally decreasing trends in TC1 and ST from high to low
tidal level. But there was no consistent difference of J observed across the tidal levels. In general, the spatial
differences of these biological parameters were highly related to substratum
types.
3.6.67
Figures 3.13 to 3.16 of Appendix O show
the temporal changes of mean species number, mean
density, H¡¦ and J at
every tidal level and in every sampling zone along
the sampling months. In general, all the biological parameters fluctuated
seasonally throughout the monitoring period. Lower mean species number and
density were recorded in dry season (Dec.) but the mean H' and J fluctuated
within a stable range.
3.6.68
From
Jun. to Dec. 2017, there were steady decreasing trends of mean species number
and density in TC2, TC3 and ST regardless of tidal levels. It might be an
unfavourable change reflecting environmental stresses. The heat stress and
serial cyclone hit were believed the causes during the wet season of 2017. It
was expected that the intertidal community would recover gradually in the
following wet season. In Mar. 2018 (present survey), increases of mean species
number and density were observed in all sampling zones. It indicated the
recovery of intertidal community.
Impact of the HKLR project
3.6.69
It was the 22nd survey of the EM&A
programme during the construction period. Based on the results, impacts of the
HKLR project were not detected on intertidal soft shore community. In case of
other abnormal phenomena (e.g. rapid or consistent decline of fauna densities
and species number) are observed, it would be reported as soon as possible.
3.7
Solid
and Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical
Waste Producer on 12 July 2012 for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix
K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental
Licenses and Permits
3.8.1
The valid environmental licenses and permits
during the reporting period are summarized in Appendix L.
4
Environmental Complaint and Non-compliance
4.1.1 The detailed air quality, water
quality and dolphin exceedances are provided in Appendix M. Also, the summaries of the
environmental exceedances are presented as follows:
Air Quality
4.1.2
No
Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5 and AMS6
during the reporting month. No Action and Limit Level exceedances of 24-hr TSP
were recorded at AMS5. Two Action Level exceedances of 24-hr TSP were recorded
at AMS6 during the reporting period.
Noise
4.1.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
4.1.4 No
Action and Limit Level exceedances for turbidity level and dissolved oxygen
level were recorded during the reporting period. 3 Action Level exceedances of
suspended solids level were recorded during the reporting period.
Dolphin
4.1.5
There was one Limit Level exceedances of dolphin
monitoring for the quarterly monitoring data (between March 2018 ¡V May 2018).
According to the contractor¡¦s information, the marine activities undertaken for
HKLR03 during the quarter of March 2018 ¡V May 2018 included seawall construction, box culvert construction, road and drainage
construction and drainage works.
4.1.6 There is no evidence
showing the current LL non-compliance directly related to the construction
works of HKLR03 (where the amounts of working vessels for HKLR03 have been
decreasing), 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 (CWD). In addition, the contractor
will implement proactive mitigation measures such as avoiding anchoring at
Marine Department¡¦s designated anchorage site ¡V Sham Shui Kok Anchorage (near
Brothers Island) as far as practicable.
4.1.7 All dolphin
protective measures are fully and properly implemented in accordance with the
EM&A Manual. According to the Marine Travel Route Plan, the travelling
speed of vessels must not exceed 5 knots when crossing the edge of the proposed
marine park. 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. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
4.2
Summary
of Environmental Complaint, Notification of Summons and Successful Prosecution
4.2.1 There was one complaint (complaint no.
COM-2017-129) received in relation to the environmental impacts (Cleanliness problem at East Coast Road) in
December 2017. Based on the investigation result, there was no direct evidence
showing that that the complaint was related to Contract No. HY/2011/03 for
complaint no. COM-2017-129.
4.2.2 A
complaint (complaint no. COM-2018-132) and a follow-ups of complaint no.
COM-2018-132 were received in February 2018 and March 2018
respectively. Based on our investigation result, the
complaint was related to Contract No. HY/2011/03 for complaint no. COM-2018-132 and a
follow-ups of complaint no. COM-2018-132. The summary of environmental complaint is
presented in Table 4.1. The details of cumulative
statistics of Environmental Complaints are provided in Appendix
N.
Table 4.1 A
Summary of Environmental Complaint for Previous Reporting Period and the
Reporting Period
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaint
|
COM-2017-129
|
ENPO¡¦s email to the Supervising
Officer¡¦s Representative and Contractor on 8 January 2018 that HyD received
a complaint lodged by a member of the public regarding cleanliness problem
at East Coast Road on 29 December 2017
|
Cleanliness problem at
East Coast Road
|
COM-2018-132
|
HyD (SOR
referred the email from HyD to Contractor and ET on 13 February 2018) and
EPD (ENPO referred the email from EPD to SOR, SOR sent the email to
Contractor and ET on 14 February 2018)
|
Complaint about Dust, Water Quality, Construction Waste, Noise and
Vibration for the Contract
|
Follow-ups of Complaint
No COM-2018-132
|
HyD (SOR
referred the email from HyD to the Contractor and ET on 16 March 2018) and
EPD (ENPO referred the email from EPD to SOR, who sent the email to the
Contractor and ET on 21 March 2018)
|
Dust and Construction Waste
|
4.2.3
Statistics on notifications of summons and
successful prosecutions are summarized in Appendix
M.
5
Comments,
Recommendations and Conclusion
5.1.1 According
to the environmental site inspections undertaken during the reporting period,
the following recommendations were provided:
¡P
The Contractor was
reminded to apply the mechanical cover of the truck during transportation at
S7.
¡P
The Contractor was reminded
to spray water to the stockpile of dust material prior to excavation at S7.
¡P
The Contractor was
reminded to spray water on the haul road to prevent dust emission at N26.
¡P
The Contractor was
reminded to spray water to the stockpile of dusty material at N4.
¡P
The Contractor was
reminded to clear the waste near HMA at S15, near plant room at S15, S7, S9,
S22, S23, S25, N1, N4, N4A, N30, N26 and HAT.
¡P
The Contractor was
reminded to clear the general refuse on the ground at S16.
¡P
The Contractor was
reminded to clear the construction waste on the ground at S15.
¡P
The Contractor was
reminded to maintain the silt curtains properly at Portion X.
¡P
The Contractor was
reminded to provide proper wheel washing facilities for cleaning vehicles
before leaving the work area at S7, S16, S25 and S28.
¡P
The Contractor was
reminded to remove the mud near gully at N30.
¡P
The Contractor was
reminded to clear the mud and waste in the u-channel at N1.
¡P
The Contractor was
reminded to remove the stagnant water inside the drip tray and the I-beam at
N4.
¡P
The Contractor was
reminded to provide drip tray for the chemical containers at N1, S7 and near
plant room at S15.
¡P
The Contractor was
reminded to remove the oil stain as chemical waste at S7.
¡P
The Contractor was
reminded to provide drip tray for the oil container at S7 and S9.
¡P
The Contractor was
reminded to clear the stagnant water inside the drip tray at HAT and S16.
5.2.1
The
impact monitoring programme for air quality, noise, water quality and dolphin
ensured that any deterioration in environmental condition was readily detected
and timely actions taken to rectify any non-compliance. Assessment and analysis
of monitoring results collected demonstrated the environmental impacts of the
contract. With implementation of the recommended environmental mitigation
measures, the contract¡¦s environmental impacts were considered environmentally
acceptable. The weekly environmental site inspections ensured that all the
environmental mitigation measures recommended were effectively implemented.
5.2.2 The recommended environmental mitigation
measures, as included in the EM&A programme, effectively minimize the
potential environmental impacts from the contract. Also, the EM&A programme
effectively monitored the environmental impacts from the construction
activities and ensure the proper implementation of mitigation measures. No
particular recommendation was advised for the improvement of the programme.
5.3.1
The construction phase and EM&A programme of
the Contract commenced on 17 October 2012. This is the twenty-third Quarterly
EM&A Report which summarizes the monitoring results and
audit findings of the EM&A programme during the reporting period from 1
March 2018 to 31 May 2018.
Air Quality
5.3.2
No
Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5 and AMS6
during the reporting month. No Action and Limit Level exceedances of 24-hr TSP
were recorded at AMS5. Two Action Level exceedances of 24-hr TSP were recorded
at AMS6 during the reporting period.
Noise
5.3.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period
Water Quality
5.3.4
No Action and Limit Level exceedances for
turbidity level and dissolved oxygen level were recorded during the reporting period.
3 Action Level exceedances of suspended solids level were recorded during the
reporting period.
Dolphin
5.3.5 There was one Limit Level exceedance of
dolphin monitoring for the quarterly monitoring data between March 2018 ¡V May
2018.
5.3.6 During
the present quarter of dolphin monitoring, no adverse impact from the
activities of this construction project on Chinese White Dolphins was
noticeable from general observations.
5.3.7 Although dolphins rarely occurred in
the area of HKLR03 construction in the past and during the baseline monitoring
period, it is apparent that dolphin usage has been dramatically reduced in NEL
since 2012, and many individuals have shifted away completely from the
important habitat around the Brothers Islands.
5.3.8
It is
critical to continuously monitor the dolphin usage in North Lantau region in
the upcoming quarters, to determine whether the dolphins are continuously
affected by the various construction activities in relation to the HZMB-related
works, and whether suitable mitigation measure can be applied to revert the situation.
Mudflat -
Sedimentation Rate
5.3.9
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.
Mudflat - Ecology
5.3.10 The
March 2018 survey was the 22nd survey of the EM&A programme
during the construction period. Based on the results, impacts of the HKLR
project could not be detected on horseshoe crabs and intertidal soft shore
community. According to the
results of present survey, the disappearance of seagrass beds was believed the
cause of serial cyclone hits rather than impact of HKLR project. Based on
previous findings, the seagrass beds were expected to recolonize the mudflat
gradually in the future, as long as the vicinal water quality remained normal. However,
recolonization was yet to be recorded in present survey (Mar. 2018) after 3-6
months of disappearance. The results of coming wet season survey (Jun.
2018) would provide a better understanding about seagrass status.
5.3.11 Environmental Site Inspection and Audit
5.3.12
Environmental site inspection was carried out on
1,7, 14, 21 and 27 March 2018; 4,11, 18 and 27 April 2018; and 7, 10, 16 and 30 May 2018. Recommendations
on remedial actions were given to the Contractors for the deficiencies
identified during the site inspections.
5.3.13
There was one complaint (complaint no.
COM-2017-129) received in relation to the environmental impacts (Cleanliness
problem at East Coast Road) in December 2017. Based on the investigation
result, there was no direct evidence showing that that the complaint was
related to Contract No. HY/2011/03 for complaint no. COM-2017-129.
5.3.14
A complaint (complaint no. COM-2018-132) and a
follow-ups of complaint no. COM-2018-132 were received in February 2018 and
March 2018 respectively. Based on our investigation result, the complaint was
related to Contract No. HY/2011/03 for complaint no. COM-2018-132 and a
follow-ups of complaint no. COM-2018-132.
5.3.15
No notification of summons and prosecution was
received during the reporting period.