Contract No. HY/2011/03
Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road
Section between Scenic
Hill and Hong Kong Boundary Crossing Facilities
Quarterly EM&A Report
No. 25 (September 2018 to November 2018)
15 March 2019
Revision 1
Main Contractor Designer
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. 6
2.4 Mitigation Measures. 6
3....... Environmental Monitoring
and Audit 7
3.1 Implementation
of Environmental Measures. 7
3.2 Air
Quality Monitoring Results. 7
3.3 Noise
Monitoring Results. 8
3.4 Water
Quality Monitoring Results. 8
3.5 Dolphin
Monitoring Results. 9
3.6 Mudflat
Monitoring Results. 20
3.7 Solid
and Liquid Waste Management Status. 33
3.8 Environmental
Licenses and Permits. 34
4....... Environmental Complaint and Non-compliance. 35
4.1 Environmental Exceedances. 35
4.2 Summary of Environmental Complaint,
Notification of Summons and Successful Prosecution. 36
5....... Comments, Recommendations and Conclusion. 37
5.1 Comments. 37
5.2 Recommendations. 37
5.3 Conclusions. 37
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-fifth 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 September 2018 to 30 November 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
|
Sep 2018
|
Oct 2018
|
Nov 2018
|
Air
Quality
|
1-hr
TSP
|
4, 10, 14, 20 and 26
|
2, 5, 11, 16, 22 and 26
|
1, 7, 13, 19, 23 and 29
|
24-hr
TSP
|
AMS5: 3, 7, 13, 19, 26 and 29
AMS6: 3, 7, 13, 19, 24 and 29
|
4, 10, 15, 19, 25 and 31
|
6, 12, 16, 22, and 28
|
Noise
|
4, 10, 20 and 26
|
2, 11, 18 and 22
|
1, 7, 13, 19 and 29
|
Water Quality
|
3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26 and 28
|
1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26, 29
and 31
|
2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 26, 28, and 30
|
Chinese
White Dolphin
|
4, 18, 20 and 26
|
4, 11, 16 and 18
|
1, 6, 8 and 13
|
Mudflat Monitoring (Ecology)
|
20 and 23
|
6, 7, 20, 21
|
-
|
Mudflat Monitoring (Sedimentation rate)
|
5
|
-
|
-
|
Site Inspection
|
5, 12, 19, and 28
|
3, 10, 16, and 26
|
2, 7, 14, 21 and 30
|
The monitoring time for TSP monitoring on 24
September 2018 at AMS5 (Ma Wan Chung Village) was less than 24-hr due to power
interruption of the high volume sampler (HVS). The 24-hr
TSP monitoring was rescheduled from 24 September 2018 to 26 September 2018.
Thunderstorm Warning was issued by the Hong Kong
Observatory on 6, 7, 8 September 2018. The mudflat monitoring on 6, 7, 8
September 2018 was cancelled due to safety reason. The mudflat monitoring was
rescheduled to 20, 23 September 2018 and 6, 7, 20, 21
October 2018.
As the Strong Wind Signal No.3 was issued by
Hong Kong Observatory in the afternoon of 12 September 2018. The water quality monitoring
for ebb tide on 12 September 2018 was cancelled due to safety reason.
No. 8 Southeast Gale or Storm Signal and Strong
Wind Signal No.3 was issued by Hong Kong Observatory on 17 September 2018. The
water quality monitoring for ebb tide and flood tide on 17 September 2018 was
cancelled due to safety reason. Also, the dolphin monitoring was rescheduled
from 17 September 2018 to 20 September 2018.
Due to boat
unavailability, the dolphin monitoring was rescheduled form 11 September 2018
to 18 September 2018, from 24 September to 26 September 2018 and from 23
October 2018 to 18 October 2018.
Due
to bad weather condition, the noise monitoring was rescheduled from 16 October
2018 to 18 October 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
|
3
|
0
|
24-hr
TSP
|
0
|
0
|
Noise
|
Leq (30 min)
|
0
|
0
|
Water Quality
|
Suspended
solids level (SS)
|
4
|
0
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin Monitoring
|
Quarterly
Analysis (Sep 2018 to Nov 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 no complaint received in relation to the environmental impacts during this
reporting period.
Notifications of Summons
and Prosecutions
There
were no notifications of summons or prosecutions received during this reporting
period.
Reporting Changes
This
report has been developed in compliance with the reporting requirements for the
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 works area WA5
was handed over to other party on 22 June 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 31 January 2018. Figure 1.1 shows
the project site boundary.
1.1.4 BMT Hong Kong Limited has been
appointed by the Contractor to implement the EM&A programme for the Contract in accordance
with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and will be
providing environmental team services to the Contract. Ramboll Hong Kong Limited was employed
by HyD as the Independent Environmental Checker (IEC)
and Environmental Project Office (ENPO) for the Project. The
project organization with regard to the environmental
works is provided in Appendix A.
1.1.5
This is the twenty-fifth 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
September 2018 to 30 November 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
|
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
|
AMS5 & AMS6
|
At least 3 times every 6 days
|
While the
highest dust impact was expected.
|
24-hr TSP
|
At least once every 6 days
|
--
|
Noise
|
Leq (30mins),
L10 (30mins) and
L90 (30mins)
|
NMS5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡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(N),
¡P Control/Far
Field Stations:
CS2(A) & CS(Mf)5,
¡P Sensitive
Receiver Stations:
SR3(N), SR4(N), SR5(N), SR10A(N) & SR10B(N2)
|
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)
|
Sep 2018
|
AMS5
|
45
|
11 ¡V 83
|
352
|
500
|
AMS6
|
51
|
14 ¡V 92
|
360
|
Oct 2018
|
AMS5
|
116
|
45 ¡V 370
|
352
|
AMS6
|
83
|
48 ¡V 193
|
360
|
Nov 2018
|
AMS5
|
67
|
34 ¡V 109
|
352
|
AMS6
|
69
|
37 ¡V 127
|
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)
|
Sep 2018
|
AMS5
|
44
|
22 ¡V 69
|
164
|
260
|
AMS6
|
69
|
23 ¡V 148
|
173
|
Oct 2018
|
AMS5
|
66
|
45 ¡V 92
|
164
|
AMS6
|
71
|
44 ¡V 102
|
173
|
Nov 2018
|
AMS5
|
66
|
36 ¡V 128
|
164
|
AMS6
|
74
|
42 ¡V 139
|
173
|
3.2.2
Three Action Level exceedances of 1-hr
TSP were recorded at AMS5 during the reporting period. No Limit Level exceedance
of 24-hrTSP were recorded at AMS5 during the reporting period. No Action and Limit
Level exceedances of 1-hr TSP and 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)
|
Sep 2018
|
NMS5
|
59
|
56 ¡V 64
|
When one documented complaint is received
|
75
|
Oct 2018
|
59
|
58 ¡V 61
|
Nov 2018
|
59
|
54 ¡V 68
|
3.3.2 No Action/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 of turbidity level and
dissolved oxygen were recorded during reporting period. No Limit Level exceedance of suspended solids were recorded during the
reporting period. 4 Action Level exceedances of
suspended solids level were recorded during the reporting period. The
exceedances of suspended solids level recorded during reporting period was 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 September
to November 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 797.27 km of
survey effort was collected, with 93.8% of the total survey effort being conducted under favorable weather
conditions (i.e. Beaufort Sea State 3 or below with good visibility). Among the two areas, 291.60 km and 505.67km of survey effort were
conducted in NEL and NWL survey areas respectively.
3.5.11 The total survey effort
conducted on primary lines was 576.22 km, while the effort on secondary lines was 221.05
km. 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 Appendix J.
3.5.12 During the six sets of
monitoring surveys conducted between September and
November 2018, six
groups of 13 Chinese White Dolphins were sighted, with
the summary table of dolphin sightings shown in Annex II of Appendix
J. All six dolphin sightings were made during on-effort search, with five
of the six on-effort dolphin sightings being 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 September to November 2018 is
shown in Figure 1 of Appendix J.
All sightings were made at the northwestern portion of the North Lantau
region, with the main concentration surrounding Lung Kwu
Chau (Figure 1 of Appendix J).
3.5.15 As consistently recorded in previous monitoring quarters, the
dolphins were completely absent from the central and eastern portions of North
Lantau waters (Figure 1 of Appendix J).
Moreover, 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 (September-November 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 22 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 drastically
different between the baseline and impact phase periods. During the present impact monitoring
period, dolphins were seldom sighted here, and mainly at the northwestern
portion of the North Lantau region, which was in stark contrast 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 autumn months in 2013-18 (Figure 2 of Appendix J). Among the six autumn periods, dolphins were regularly sighted in NWL
waters in 2013, but such usage there was dramatically reduced in the five
subsequent autumn periods, with their only occurrences mostly concentrated in
the waters surrounding Lung Kwu Chau in the past four
autumn periods (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 1.29 sightings and 2.79 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
(September ¡V
November 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 (4 & 17 Sep 2018)
|
0.00
|
0.00
|
Set 2 (20 & 26 Sep 2018)
|
0.00
|
0.00
|
Set 3 (4 & 11 Oct 2018)
|
0.00
|
0.00
|
Set 4 (16 & 18 Oct 2018)
|
0.00
|
0.00
|
Set 5 (1
& 6 Nov
2018)
|
0.00
|
0.00
|
Set 6 (8 & 13 Nov 2018)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (4 & 17 Sep 2018)
|
0.00
|
0.00
|
Set 2 (20 & 26 Sep 2018)
|
1.62
|
3.24
|
Set 3 (4 & 11 Oct 2018)
|
0.00
|
0.00
|
Set 4 (16 & 18 Oct 2018)
|
1.63
|
3.27
|
Set 5 (1
& 6 Nov
2018)
|
5.81
|
9.69
|
Set 6 (8 & 13 Nov 2018)
|
0.00
|
0.00
|
Table 3.5 Comparison of average dolphin encounter rates from impact
monitoring period (September to November 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
|
1.51 ¡Ó
2.25
|
9.85 ¡Ó 5.85
|
2.70 ¡Ó 3.78
|
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
22 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 five groups of 19 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
|
June-August
2018 (Impact)
|
0.00
|
0.00
|
September-November 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 autumn 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 84.7% and 94.0% respectively) were only tiny 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
|
|
June-August 2018 (Impact)
|
1.16 ¡Ó 1.39
|
2.87 ¡Ó 3.32
|
|
September-November 2018 (Impact)
|
1.51 ¡Ó 2.25*
|
2.70 ¡Ó 3.78*
|
|
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 autumn months
were in blue and marked with asterisk.
3.5.23 Notably, when comparing the quarterly periods in autumn months, the
quarterly encounter rates in the autumn of 2018 dropped to the lowest among all
autumn periods during the HKLR03 construction phase. The dramatic drop in dolphin occurrence
during this quarter should raise serious concerns, and 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 (24th quarter of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.0029 and 0.0143 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 24 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 2018). Apparently there was very 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 one to four
individuals per group in North Lantau region during September to November 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 (Sep
2018 ¡V Nov 2018) and Baseline Monitoring Period (Sep ¡V
Nov 2011)
Survey Area
|
Average Dolphin Group Size
|
Reporting Period
|
Baseline Monitoring Period
|
Overall
|
2.17
¡Ó 0.98 (n = 6)
|
3.72
¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
2.17
¡Ó 0.98 (n = 6)
|
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 September to
November 2018 was much lower than the one recorded during the three-month
baseline period, but it should be noted that the sample size of six dolphin
groups in the present quarter was only a small fraction of the sample size of
66 dolphin groups sighted during the baseline period (Table 3.8).
3.5.31 Notably, with the exception of one medium-sized group with four
animals, the other five dolphin groups were very small with 1-2 individuals per
group only (Annex II of Appendix J).
Habitat
Use
3.5.32 From September to November 2018, only six grids recorded dolphin occurrence. The only grid with
moderately high dolphin density was located adjacent to Lung Kwu Chau, while the other grids recorded low to very low
DPSE values (Figures 3a and 3b of Appendix J).
3.5.33 Notably, all grids near HKLR03/HKBCF reclamation sites as well as
HKLR09/TMCLKL alignments did not record any presence of dolphins at all during
on-effort search in the present quarterly period (Figures
3a and 3b of Appendix J).
3.5.34
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.
3.5.35 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 4 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 4 of Appendix J).
3.5.36 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 during the baseline period, especially around Sha
Chau, near Black Point, to the west of the airport, as well as between Pillar
Point and airport platform. In
contrast, only several grids with low to moderate dolphin densities were
located at the northwestern portion of North Lantau waters during the present
impact phase period (Figure 4 of Appendix J).
Mother-calf Pairs
3.5.37 During the present quarterly period, no young calf was sighted at all among the six groups of dolphins.
Activities and Associations with Fishing Boats
3.5.38 Only one of the six dolphin groups was
engaged in feeding and socializing activities (with both activities occurred
during the same sighting), while no group was engaged in traveling or
milling/resting activity during the three-month
study period.
3.5.39 Distribution of dolphins
engaged in various activities during the present three-month period and baseline period is shown in Figure 5 of
Appendix J. The only dolphin group engaged in both
feeding and socializing activities was sighted to the north of Lung Kwu Chau (Figure 5
of Appendix J). In comparison, the distribution of various dolphin
activities during the present impact phase monitoring period was very different
from the baseline period with a much more restricted area of occurrence (Figure 6 of Appendix J).
3.5.40 Notably, none of the six dolphin groups was found to be associated
with any operating fishing vessel during the present impact phase period.
Summary Photo-identification works
3.5.41 From September to November 2018, about 300 digital photographs of
Chinese White Dolphins were taken during the impact phase monitoring surveys
for the photo-identification work.
3.5.42 In total, six individuals sighted 10 times altogether were
identified (see summary table in Appendix
III of Appendix J and photographs of identified individuals in Appendix IV of Appendix J). All of these
re-sightings were made in NWL. Four
of the six individuals (NL136, NL182, NL261 and NL328) were re-sighted twice,
while the other two individuals (NL272 and NL286) were re-sighted once during
the three-month period (Annex
III of Appendix J).
3.5.43 Notably, one of these six individuals (NL136) was also sighted in
NWL waters during the HKBCF monitoring surveys under the same three-month
period. However, none of them was
sighted in WL waters during the HKLR09 monitoring surveys from the September to
November 2018, which implied their limited movements across different survey
areas during this quarterly monitoring period.
Individual range use
3.5.44 Ranging patterns of the six individuals identified during the
three-month study period were determined by fixed kernel method,
and are shown in Annex V of Appendix J.
3.5.45 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.
3.5.46 On the other hand, in contrary to previous monitoring quarters, none
of the six individuals have extended their range use to WL waters during the
same autumn quarter of 2018, while none of the individuals that consistently
utilized WL waters in the past have extended their range use to NWL waters
either during the present quarter.
3.5.47 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.
Action Level / Limit Level Exceedance
3.5.48
There was one Limit
Level exceedance of dolphin monitoring for the quarterly monitoring data (between
September 2018 ¡V November 2018). According to the
contractor¡¦s information, the marine activities undertaken for HKLR03 during
the quarter of September 2018 ¡V November 2018 included seawall construction and box culvert construction.
3.5.49 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.
3.5.50
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.
3.5.51
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.
3.5.52
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).
3.5.53 For the comparison between the baseline period and the present
quarter (24th quarter of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.0029 and 0.0143 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.
3.5.54
For comparison between
the baseline period and the cumulative quarters in impact phase (i.e. (i.e. the first 24 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).
3.5.55 The AFCD monitoring data during September to
November 2018 has been reviewed by the dolphin specialist. During the same
quarter, no dolphin was sighted from 172.60 km of survey effort on primary
lines in NEL, while nine groups of 22 dolphins were sighted from 216.88 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 autumn 2018
in NEL and NWL survey area is accurate.
3.5.56
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 Brothers 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.
3.5.57 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.
3.5.58 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.
3.5.59 ETs shall keep reviewing the implementation status
of the dolphin related mitigation measures and remind the contractor to
implement he relevant measures.
3.5.60 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.
3.5.61 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.
3.5.62 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.
3.5.63
The marine travel route will
shift along the edge of the Brothers 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.
3.5.64 It was noted 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.
3.5.65 There was a discussion on exploring possible further
mitigation measures, for example, controlling the underwater noise. It was
noted that the EIA reports for the projects suggested several mitigation
measures, all of which have been implemented.
3.6
Mudflat
Monitoring Results
Sedimentation Rate
Monitoring
3.6.1 The baseline sedimentation rate monitoring was in September 2012 and
impact sedimentation rate monitoring was undertaken on 5
September 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
(September 2018)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.184
|
816678.671
|
1.141
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.199
|
815831.552
|
0.984
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.568
|
815953.303
|
1.501
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.462
|
816151.451
|
1.152
|
Table 3.10 Comparison
of Measurement
|
Comparison of measurement
|
Remarks and
Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.024
|
-0.056
|
0.191
|
Level
continuously increased
|
S2
|
-0.073
|
0.021
|
0.120
|
Level continuously increased
|
S3
|
-0.017
|
-0.005
|
0.160
|
Level continuously increased
|
S4
|
0.029
|
0.070
|
0.221
|
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(N) was conducted in September and
October 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 in Table 3.11:
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)
|
03-Sep-2018
|
5.7
|
7.5
|
5.4
|
5.5
|
6.7
|
6.2
|
05-Sep-2018
|
6.0
|
3.8
|
3.0
|
7.3
|
6.4
|
8.5
|
07-Sep-2018
|
6.7
|
3.5
|
5.6
|
7.2
|
10.3
|
14.8
|
10-Sep-2018
|
5.0
|
10.3
|
13.3
|
5.7
|
6.9
|
15.9
|
12-Sep-2018
|
See Remark
1
|
See Remark
1
|
See Remark
1
|
5.0
|
6.7
|
10.2
|
14-Sep-2018
|
5.3
|
4.4
|
6.3
|
5.6
|
5.0
|
6.8
|
17-Sep-2018
|
See Remark
2
|
See Remark
2
|
See Remark
2
|
See Remark
2
|
See Remark
2
|
See Remark
2
|
19-Sep-2018
|
6.4
|
2.7
|
6.8
|
6.4
|
5.7
|
6.0
|
21-Sep-2018
|
6.6
|
4.0
|
4.3
|
7.4
|
8.6
|
8.0
|
24-Sep-2018
|
6.2
|
5.0
|
7.7
|
6.2
|
4.4
|
4.1
|
26-Sep-2018
|
5.7
|
6.1
|
6.1
|
5.9
|
9.5
|
12.5
|
28-Sep-2018
|
5.6
|
5.8
|
10.0
|
5.8
|
7.1
|
11.9
|
Average for the month of Sep 2018
|
5.9
|
5.3
|
6.8
|
6.2
|
7.0
|
9.5
|
01-Oct-2018
|
5.9
|
4.7
|
8.1
|
5.9
|
5.0
|
8.2
|
03-Oct-2018
|
5.5
|
3.5
|
5.1
|
5.8
|
7.9
|
9.2
|
05-Oct-2018
|
5.6
|
9.6
|
7.5
|
6.2
|
10.3
|
13.4
|
08-Oct-2018
|
6.1
|
10.2
|
6.1
|
5.8
|
6.4
|
5.9
|
10-Oct-2018
|
5.8
|
8.7
|
6.3
|
5.8
|
8.6
|
9.8
|
12-Oct-2018
|
6.3
|
8.0
|
8.4
|
5.8
|
9.2
|
12.9
|
15-Oct-2018
|
5.9
|
7.5
|
6.8
|
5.9
|
8.4
|
4.3
|
17-Oct-2018
|
6.3
|
4.9
|
4.0
|
6.0
|
3.1
|
2.8
|
19-Oct-2018
|
6.4
|
2.3
|
1.2
|
6.6
|
4.2
|
5.4
|
22-Oct-2018
|
6.5
|
4.5
|
2.5
|
6.6
|
6.3
|
7.1
|
24-Oct-2018
|
6.4
|
2.6
|
6.6
|
6.0
|
3.2
|
7.9
|
26-Oct-2018
|
6.5
|
3.2
|
5.9
|
6.3
|
2.8
|
4.6
|
29-Oct-2018
|
6.6
|
1.5
|
5.3
|
6.7
|
3.1
|
9.5
|
31-Oct-2018
|
6.5
|
1.5
|
3.3
|
7.2
|
2.5
|
4.8
|
Average for the month of Oct 2018
|
6.2
|
5.2
|
5.5
|
6.2
|
5.8
|
7.6
|
Remarks:
1) Due to adverse weather condition (hoisting Tropical Cyclone Warning
Signal, No. 3), water quality monitoring for ebb tide at station SR3(N) on 12
September 2018 was cancelled due to safety reasons.
2) Due to adverse weather condition (hoisting No. 8 Southeast Gale or
Storm Signal and Strong Wind Signal No.3), water quality monitoring for ebb
tide and flood tide at station SR3(N) on 17 September 2018 was cancelled due
to safety reasons.
|
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 September and October
2018 (totally 6 sampling days between 20th September and 21st October
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 government
agency units.
Horseshoe Crabs
3.6.8 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 20th (for TC3 and ST) and 23rd (for TC1 and TC2)
September 2018. The weather was generally hot and sunny on all survey days.
3.6.9 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 inhabiting 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 government agency units.
Seagrass Beds
3.6.10 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 20th (for TC3 and
ST) and 23rd (for TC1 and TC2) September 2018. The weather was
generally hot and sunny on all survey days.
Intertidal Soft Shore Communities
3.6.11
The
intertidal soft shore community surveys were conducted in low tide period 6th
(for TC2), 7th (for ST), 20th (for TC1) and 21st
(for TC3) October 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.
3.6.12
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.
3.6.13
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.
3.6.14
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), AFCD
(2018).
Data Analysis
3.6.15
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
3.6.16 In the present survey, two species of horseshoe crab Carcinoscorpius rotundicauda (total 115 ind.) and Tachypleus tridentatus (total 37 ind.) were
recorded. The recorded individuals were mainly distributed along the shoreline
from TC3 to ST. Grouping of 2-25 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.
3.6.17 Table 3.1 of Appendix O summarizes the survey results of horseshoe crab
in the present survey. For Carcinoscorpius rotundicauda, highest number of individuals were found in ST followed by TC3 and
TC1. In ST, 64 individuals
were found with average body size 34.83 mm (24.87-62.79 mm) resulting in moderate search record (10.7 ind. hr-1 person-1). In TC1, there were 17 individuals average body size 44.03 mm (prosomal
width ranged 34.37-65.67 mm). In TC3, there were 33 individuals with average body size 32.15 mm
(9.96-62.94 mm). The search records (4.3-5.5 ind. hr-1 person-1) were at low-moderate
level in both zones. In TC2, there was only 1 individual with body size 47.44
mm resulting in very low search record (0.3 ind. hr-1
person-1).
3.6.18 There was similar pattern of
survey results for Tachypleus tridentatus. Highest number of individuals were found in ST (23 ind.) with average
body size 50.16 mm
(38.90-70.97 mm), resulting in low-moderate search record (3.8 ind. hr-1 person-1). In TC1 and TC3, few
individuals (6-8) were found with average body
size 38.70-57.00 mm (prosomal width ranged 25.78 - 69.99 mm). The search record
was at low level (1.3 -
1.5 ind. hr-1 person-1). No individual was found in TC2.
3.6.19 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 and Jun. 2018, one mating pair was of Carcinoscorpius rotundicauda was found in TC3 (Dec.
2017: male
127.80 mm, female 144.61 mm; Jun. 2018: male 139 mm, female 149 mm). Figure 3.2 of Appendix O shows the photographic records of all mating pairs found. 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. 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. Based on the frequency of encounter, the
shoreline between TC3 and ST should be more suitable mating ground. 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. In present survey
(Sep. 2018), two newly hatched individuals were also found in TC1 and TC2
(prosomal width 6.00-6.87 mm) (Figure 3.4 of Appendix I) while species identification was not possible.
3.6.20 Despite of mating pair, there were occasional records of large
individuals of Carcinoscorpius rotundicauda
(prosomal width ranged 114.45 - 178.67 mm, either single or in pair) and Tachypleus tridentatus (prosomal
width 103 mm) (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.
3.6.21
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.
3.6.22
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
3.6.23
Figures
3.5 and 3.6 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.
3.6.24
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 SeptemberOne 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). From Dec. 2017 to Sep. 2018 (present survey), the search records of both species increased again
to low-moderate level in TC3 and ST. Relatively higher population
fluctuation of Tachypleus tridentatus was
observed in TC3..
3.6.25
For TC1, the search record was at low to moderate 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 ind. in Jun.
2018;1 ind. in Sep. 2018).
3.6.26
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 Jun. 2018. In Sep. 2018 (present survey), larger individuals were
found in ST and TC1 again. For Tachypleus tridentatus, larger individuals were usually found in ST and TC3 followed by
TC1 throughout the monitoring period.
3.6.27
In general, it was
obvious that the shoreline along 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
3.6.28 Throughout
the monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures 3.4 and 3.5 of Appendix O). 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 search 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 2016). 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, the weather was cold (13-15 ºC during dawn) that very
few individuals of both species could be found as mentioned above.
3.6.29
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. In 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 Chung 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).
3.6.30
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. From Sep. 2017 to
Sep. 2018 (present survey), moderate numbers of individual were found in TC3
and ST indicating a stable population size. Lower population size compared with
that in Jun. 2017 was believed the cause of natural mortality.
3.6.31 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
3.6.32 Figure
3.7 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 Sep. 2018, 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 (prosomal
width 60-90 mm) along the sampling months. Juveniles reaching this size might
gradually migrate to sub-tidal habitats.
3.6.33
For Tachypleus tridentatusthe 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 Sep.
2018 (present survey), 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
3.6.34 Figure
3.8 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.
3.6.35 For Tachypleus tridentatusa 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 Jun. 2018, the major size
range increased slightly from 40-50 mm to 45-60 mm indicating a continuous
growth. In Sep. 2018 (present survey), decrease of major size was noted again
that might reflect new round of spawning. 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.
3.6.36
As a summary for horseshoe crab populations in TC3 and ST, there were
spawning of Carcinoscorpius rotundicauda
from 2014 to 2018 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. From 2016
to 2018, new rounds of spawning were recorded in ST while increasing number of
individuals and body size was noticed.
Impact of the HKLR
project
3.6.37 It was
the 24th 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
3.6.38 Since the commencement of the
EM&A monitoring programme, two species of
seagrass Halophila ovalis and Zostera japonica were recorded in TC3 and ST (Figure 3.9 of Appendix O). In general, Halophila
ovalis
was occasionally found in TC3 in few, small to medium patches. But it was
commonly found in ST in medium to large seagrass bed. Moreover, it had
sometimes grown extensively and had covered significant mudflat area at 0.5-2.0 m above C.D. between TC3 and ST. Another seagrass species
Zostera japonica was found in ST only. It was relatively lower
in vegetation area and was co-existing with Halophila ovalis nearby the mangrove strand at
2.0 m above C.D..
3.6.39 Table 3.2 of Appendix O summarizes the results of seagrass beds survey. In ST, two small sized patches of Halophila ovalis were found while the total
seagrass bed area was about 22.5 m2 (Figure
3.10 of Appendix O). The
relatively larger patch had area ~12
m2 in high vegetation coverage 80%, located at tidal zone 1.5-2.0 m above
C.D nearby mangrove plantation. At vicinity, there was a small, horizontal
strand (~10.5 m2, low coverage 5%). Another
seagrass species Zostera japonica was not found in present survey. Annex
II of Appendix O shows the complete
record of seagrass survey
3.6.40
According
to the previous results, majority of seagrass bed was confined in ST, the
temporal change of both seagrass species was investigated in details:
Temporal variation of seagrass beds
3.6.41
Figure 3.11 of Appendix I 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. 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. From Sep. 2017 to Sep. 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 3.12 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 3.12 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). The whole recolonization process took about 2.5 years.
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 3.12 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 IS5 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 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). Until Jun.
2018, new, small-medium seagrass patches were found at the usual location
(seaward side of mangrove plantation at 2.0 m C.D.) again, indicating the
recolonization. However, the
seagrass bed area decreased sharply to 22.5 m2 in Sep. 2018 (present
survey). Again, it was believed the hit of super cyclone in Sep. 2018 (Mangkhut on 16th Sep., highest signal 10). It
was expected that the recolonization would occur later and slower than previous
round (more than 2 years).
Impact of the HKLR project
3.6.53
It was the 24th survey of the
EM&A programme
during the construction period. Throughout the monitoring period, the
disappearance of seagrass beds was believed the cause of cyclone hits rather
than impact of HKLR project. Slow and gradual recolonization of seagrass was expected in the following months.
Intertidal Soft
Shore Communities
3.6.54
Table 3.3 and Figure 3.13 of Appendix O show the substratum types along the horizontal
transect at every tidal level in all sampling
zones. The relative
distribution of substratum types 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¡¦ (70-80%) were
recorded at all tidal levels followed by ¡¥Sands¡¦ (20%).
¡P
In TC2, high percentages of ¡¥Sands¡¦ (60-70%) were recorded at high and
mid tidal levels followed by ¡¥Soft mud¡¦ (20-40%). At low tidal level, the major
substratum type was 'Soft mud' (80%) followed by ¡¥Sands¡¦ (20%).
¡P
In TC3, the main substratum was ¡¥Sands¡¦ (100%) at high and mid tidal
levels while it was ¡¥Gravels and Boulders¡¦ (100%) at low tidal level.
¡P
In ST, ¡¥Gravels and Boulders¡¦ was the main substratum (90-100%) at high
and mid tidal levels. At low tidal level, there was higher percentage of
¡¥Sands¡¦ (60%) followed by 'Soft mud' (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 3.4 of Appendix O lists the total abundance, density and number of taxon
of every phylum in this
survey. A total of 17453 individuals
were recorded. Mollusca was clearly the
most abundant phylum (total abundance 17166 ind., density 572 ind. m-2, relative
abundance 98.4 %). The second and third abundant phya were Arthropoda (201 ind., 7 ind. m-2, 1.2 %) and Annelida
(60 ind., 2 ind. m-2, 0.3 %) respectively.
Relatively other phyla were very low in abundances (density £1 ind. m-2, relative
abundance £0.0 %). Moreover, the most diverse phylum was Mollusca (31 taxa) followed by Arthropoda (9 taxa) and Annelida (8 taxa). There was 1-2
taxa recorded only for other phyla..
3.6.57 The taxonomic resolution and complete list of recorded fauna are shown in Annexes IV and V of Appendix O respectively. As reported in Jun. 2018,
taxonomic revision of three potamidid snail species was conducted according to
the latest identification key published by Agriculture, Fisheries and
Conservation Department (details see AFCD, 2018), the species names of
following gastropod species were revised:
¡P
Cerithidea cingulata was revised as Pirenella asiatica
¡P
Cerithidea djadjariensis was revised as Pirenella incisa
¡P
Cerithidea rhizophorarum was revised as Cerithidea moerchii
In present survey, taxonomic revision was conducted on another snail
species while the specie name was revised.:
¡P
Batillaria bornii was
revised as Clypeomorus bifasciata
3.6.58 Table 3.5 of Appendix O shows the number of
individual, relative abundance and density of each phylum in every sampling
zone. The total abundance (2357-6005 ind.) varied
among the four sampling zones while the phyla distributions were similar. In general, Mollusca was the most dominant phylum (no. of
individuals: 2243-5909
ind.; relative abundance
95.2-99.4 %; density 299-788 ind. m-2). Other phyla were much lower in number of individuals. Arthropoda (26-76 ind.; 0.5-3.2 %; 3-10 ind.
m-2) and Annelida (2-33 ind.; 0.1-1.4 %; 0-4 ind. m-2) were
the second and third abundant phylum respectively. Relatively other phyla were very low in
abundance in all sampling zones.
Dominant species in
every sampling zone
3.6.59
Table 3.6 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 regarded as common species.
3.6.60
In TC1, the substratum was mainly ¡¥Gravels and Boulders¡¦ at all tidal levels.
It was clearly dominated by gastropod Batillaria multiformis
(651 ind. m-2,
relative abundance 72 %) at very high density. At mid tidal level, gastropod Batillaria multiformis
(361 ind. m-2,
57 %) was still dominant followed by gastropod Monodonta
labio (117 ind. m-2,
18 %) at low-moderate density. At low tidal level, there were few abundant
gastropods Batillaria multiformis
(164 ind. m-2, 29 %), Monodonta
labio (136 ind. m-2,
24 %) and Pirenella incisa
(56 ind. m-2, 10 %) at low-moderate densities. Moreover, rock
oyster Saccostrea cucullata (104 ind. m-2,
19 %, attached on boulders) was also abundant.
3.6.61
In TC2, the
substratum types were either 'Sands' or 'Soft mud' at high and mid tidal levels. Gastropods Pirenella asiatica (49-149 ind. m-2, 15-30%), Pirenella incisa
(48-118 ind. m-2, 14-24%), Batillaria
zonalis (80-117
ind. m-2, 16-35%) were the abundant taxa at low-moderate densities. Moreover rock oyster Saccostrea cucullata
(56-63 ind. m-2, 12-19%, attached on boulders) was also abundant at
low densities. At low tidal level (main substratum type ¡¥Soft mud¡¦), there was
only one abundant gastropod Batillaria zonalis (65 ind. m-2, 56 %) at low density.
3.6.62 TC3, the substratum types
were mainly ¡¥Sands¡¦ at high and mid tidal levels. Gastropod Pirenella
incisa (352-383
ind. m-2, 41-49 %) was dominant followed by gastropod Pirenella asiatica (134-194 ind. m-2, 14-27 %) at
low-moderate density. Moreover gastropod Batillaria multiformis
(368 ind. m-2, 40 %) was abundant at high tidal level. At low tidal
level (major
substratum: ¡¥Gravels and Boulders¡¦), gastropod Monodonta labio (289 ind. m-2, 38 %) and rock oyster Saccostrea cucullata (258
ind. m-2, 34 %, attached on boulders) were abundant at moderate densities,
followed by gastropod Lunella coronata
(87 ind. m-2, 11 %)..
3.6.63
In ST, the major substratum types were mainly
¡¥Gravels and Boulders¡¦ at high and mid tidal levels. At high tidal level,
gastropod Monodonta labio (215 ind. m-2, 36 %) was the most
abundant at moderate density. Other abundant gastropods Batillaria
multiformis (131 ind. m-2, 22 %) and Clypeomorus bifasciata
(60 ind. m-2, 10 %) were at low-moderate densities. At mid tidal
level, rock oyster Saccostrea cucullata (166 ind. m-2,
25%) and Monodonta labio (163 ind. m-2, 25 %) were
abundant at low-moderate densities followed by other gastropods Lunella coronata
(97 ind. m-2, 15 %) and Pirenella
asiatica (76 ind. m-2, 12 %). At low tidal level (major substratum types: ¡¥Sands¡¦ and 'Soft
mud'), there were two abundant gastropods Pirenella incisa (70 ind. m-2, 25 %)
and Lunella coronata
(58 ind. m-2, 21 %). Rock oyster Saccostrea cucullata (42 ind. m-2, 15 %) was also
common.
3.6.64
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: 4532 ind.,
relative abundance 26.0 %), Pirenella incisa (3005 ind., 17.2 %), , Pirenella asiatica (1970
ind., 11.3 %) and Batillaria zonalis (907 ind., 5.2 %) were the most commonly occurring species on sandy and soft mud
substrata. Rock
oyster Saccostrea cucullata (2135 ind., 12.2 %), gastropods Monodonta labio
(2513 ind., 14.4 %) and Lunella coronata (853 ind., 4.9 %) were the commonly occurring species inhabiting
gravel and boulders substratum.
Biodiversity
and abundance of soft shore communities
3.6.65
Table
3.7 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.
3.6.66 Among the sampling zones, the mean species number of ST (10
spp. 0.25 m-2) was slightly higher than other sampling zones (7-8
spp. 0.25 m-2). The mean density of TC1 and TC3 (700-801 ind. m-2)
were higher than ST (513 ind. m-2) followed by TC2 (314 ind. m-2).
Overall, ST was relatively higher in H'
(1.6) due to higher species number and even taxa distribution. In TC1 and TC3, the
higher densities were mainly accounted by 1-2 abundant
gastropods while it resulted in lower H¡¦
(1.2). In TC2, lower species number and density also resulted in lower H' (1.2). The J was similar (0.6-0.7) among all sampling zones.
3.6.67
Among the tidal levels, there were slightly increasing trends of mean species number and H' from high to low tidal level in TC1
and TC3 but vice versa in TC2 and ST. A general decreasing trend of mean
density was observed from high to low tidal level in all sampling zones. No difference
of J was found between the tidal
levels. In general, the spatial differences of these biological parameters were
highly related to substratum types.
3.6.68
Figures 3.14 to 3.17 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.
3.6.69
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. From Mar. to Sep. 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
3.6.70
It was the 25th 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, noise, 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
Three Action Level exceedances of 1-hr
TSP were recorded at AMS5 during the reporting period. No Limit Level
exceedance of 24-hrTSP were recorded at AMS5 during the reporting period. No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS6 during the
reporting period.
Noise
4.1.3 No Action/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 of turbidity level and dissolved oxygen were recorded during the reporting
period. No Limit Level exceedance of suspended solids were recorded during the
reporting period. 4 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 September 2018 ¡V
November 2018). According to the contractor¡¦s information, the marine
activities undertaken for HKLR03 during the quarter of September 2018 ¡V
November 2018 included seawall construction and box culvert
construction.
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 Brothers
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 no complaint received during the reporting period. The details of
cumulative statistics of Environmental Complaints are provided in Appendix N.
4.2.2 No notification of summons and prosecution was received during the
reporting period. Statistics on notifications of summons and successful
prosecutions are summarized in Appendix M.
4.2.3
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 provide a drip
tray for the generator at N4.
¡P The Contractor was reminded to provide water
spraying for the dry stockpile at S7.
¡P The Contractor was reminded to provide water
spraying for the dusty materials prior to loading/unloading/handling at S7.
¡P The Contractor was reminded to cover the dusty
materials loaded in the dump truck at S7.
¡P The Contractor was reminded to provide drip
trays for the chemical containers at N4.
¡P The Contractor was reminded to remove the
chemical containers at S15, N4 and WA4.
¡P The Contractor was reminded to remove the
stockpile at N4.
¡P The Contractor was reminded to remove the waste
at N4, S7, S15, PR10 and LCSD.
¡P The Contractor was reminded to remove the waste
from S7, LCSD.
¡P The Contractor was reminded to remove the
stagnant water at S7, S9, S15, N4, S15.
¡P The Contractor was reminded to remove the
stagnant water from the l-beam at N4.
¡P The Contractor was reminded to remove the
stagnant water inside the drip tray of the generator from N4.
¡P The Contractor was reminded to remove the
accumulated waste on the ground from N4 and S7.
¡P The Contractor was reminded to clear the inert
waste from N4.
¡P The Contractor was reminded to remove the
accumulated waste from a skip at S7.
¡P The Contractor was reminded to remove the oil
stain from N4 and N13A.
¡P The Contractor was reminded to remove the
abandoned water barriers at N4.
¡P The Contractor was reminded to fix the water
leakage problem at LCSD.
¡P The Contractor was reminded to maintain the silt
curtains properly at Portion X.
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-fifth Quarterly EM&A
Report which summarizes the
monitoring results and audit findings of the EM&A programme
during the reporting period from 1 September 2018 to 30 November
2018.
Air Quality
5.3.2
Three Action Level exceedances of 1-hr
TSP were recorded at AMS5 during the reporting period. No Limit Level
exceedance of 24-hrTSP were recorded at AMS5 during the reporting period. No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS6 during the
reporting period.
Noise
5.3.3
No Action/Limit Level exceedances for noise were recorded during daytime
on normal weekdays of the reporting period.
Water Quality
Dolphin
5.3.5
There was one Limit Level exceedance of dolphin monitoring for the
quarterly monitoring data between September 2018 ¡V November 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
Environmental Site Inspection and Audit
5.3.11 Environmental site inspection was carried out on 5, 12, 19, and 28 September 2018; 3, 10, 16 and 26 October 2018.; and 2, 7, 14, 21 and 30 November 2018. Recommendations on remedial actions were given to the Contractors
for the deficiencies identified during the site inspections.
5.3.12 There was no complaint received
in relation to the environmental impacts during this reporting period.
5.3.13 No notification of summons and prosecution was received during the reporting
period.