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. 21 (September 2017 to November 2017)
26 April 2018
Revision 1
Main Contractor Designer
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 Asia Pacific Limited has been appointed by
the Contractor to implement the Environmental Monitoring & Audit (EM&A)
programme for the Contract in accordance with the Updated EM&A Manual for
HKLR (Version 1.0) and will be providing environmental team services to the
Contract.
This is the twenty-first 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
to 30 November 2017.
Environmental
Monitoring and Audit Progress
The EM&A
programme were undertaken in accordance with the Updated EM&A Manual for
HKLR (Version 1.0). A summary of
the monitoring activities during this reporting period is presented as below:
Monitoring Activity
|
Monitoring Date
|
September 2017
|
October
2017
|
November
2017
|
Air
Quality
|
1-hr
TSP
|
1, 7, 13, 19, 25 and 29
|
3, 9, 13, 19, 25 and 31
|
6, 10, 16, 22 and 28
|
24-hr
TSP
|
6, 12, 18, 22, 28 and 30
|
6, 12, 18, 24 and 30
|
3, 9, 15, 22 and 27 for AMS5;
3, 9, 15, 21 and 27 for AMS6
|
Noise
|
7, 13, 19 and 25
|
3, 9, 19, 25 and 31
|
6, 16, 22 and 28
|
Water
|
1, 4, 6, 8, 11, 13, 15, 18, 20, 22, 25,
27 and 29
|
2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25,
27 and 30
|
1, 3, 6, 8, 10, 13, 15, 17, 20, 22, 24,
27 and 29
|
Chinese
White Dolphin
|
15, 18, 22 and 29
|
4, 9, 18 and
26
|
1, 8, 17 and
24
|
Mudflat
Monitoring (Ecology)
|
2, 3, 6, 16 and 17
|
--
|
--
|
Mudflat
Monitoring (Sedimentation rate)
|
16
|
--
|
--
|
Site Inspection
|
6, 13, 20 and 29
|
4,
11, 18, 25 and 31
|
8,
15, 22 and 28
|
Due to the
hoisting of Strong Wind Signal and Typhoon Signal No. 3 by the Hong Kong
Observatory, the water quality monitoring at mid-ebb tide was cancelled on 4
September 2017. No substitute monitoring was conducted due to boat
unavailability.
Due to bad
weather condition, the sedimentation rate monitoring was rescheduled from 4
September 2017 to 16 September 2017.
Due to concern
of adverse weather forecast in the mid-September 2017, the mudflat monitoring
was rescheduled from 9-12 September 2017 to 6, 16 and 17 September 2017.
Due to boat
unavailability, the dolphin monitoring was rescheduled from 26 September 2017
to 29 September 2017, from 11 October 2017 to 9 October 2017 and from 16
November 2017 to 17 November 2017.
Due to
unfavourable weather condition, the dolphin monitoring was rescheduled from 16
October 2017 to 18 October 2017.
There was a
problem of vessel and the vessel needed to be maintained on 20 October 2017.
The dolphin monitoring was rescheduled from 20 October 2017 to 26 October 2017.
Due to power
interruption of the High Volume Sampler, the 24-hr TSP monitoring on 21
November 2017 at Ma Wan Chung Village (AMS5) was rescheduled to 22 November
2017.
Breaches
of Action and Limit Levels
A summary of environmental exceedances for this
reporting period is as follows:
Environmental Monitoring
|
Parameters
|
Action Level (AL)
|
Limit Level (LL)
|
Air Quality
|
1-hr
TSP
|
0
|
0
|
24-hr
TSP
|
0
|
0
|
Noise
|
Leq
(30 min)
|
0
|
0
|
Water Quality
|
Suspended
solids level (SS)
|
17
|
3
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin Monitoring
|
Quarterly
Analysis (Sep 2017 to Nov 2017)
|
0
|
1
|
The Environmental Team investigated all
exceedances and found that they were not project related.
All investigation reports for exceedances of the
Contract have been submitted to ENPO/IEC for comments and/or follow up to
identify whether the exceedances occurred related to other HZMB contracts.
Implementation of Mitigation Measures
Site inspections were carried out on a weekly
basis to monitor the implementation of proper environmental pollution control
and mitigation measures for the Project.
Potential environmental impacts due to the construction activities were
monitored and reviewed.
Complaint Log
There was one complaint received in relation to
the environmental impacts during the reporting period.
A summary of environmental complaints for this
reporting period is as follows:
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaints
|
COM-2017-122
|
1823 Integrated
Call Centre received a complaint lodged by a member of the public on 30 September 2017. ET received complaint details on 3 October 2017.
|
Cleanliness problem at Tung Fai Road
|
For Environmental Complaint
No. COM-2017-122, complaint investigation was
undertaken. Based on the investigation result, there is no direct evidence
showing that the complaint is related to Contract No. HY/2011/03.
Nevertheless, in order to enhance dust suppression measures, the Contractor
will increase the frequency of road cleaning by water bowser from three times
per day to four times per, subject to regular review with relevant stakeholders
in the vicinity.
Notifications of Summons and Prosecutions
There were no notifications of summons or
prosecutions received during this reporting period.
Reporting Changes
This report has been developed in compliance
with the reporting requirements for the subsequent EM&A reports as required
by the Updated EM&A Manual for HKLR (Version 1.0).
The proposal for the change of Action Level and
Limit Level for suspended solid and turbidity was approved by EPD on 25 March
2013.
The revised Event and Action Plan for dolphin
monitoring was approved by EPD on 6 May 2013.
The original monitoring station at IS(Mf)9
(Coordinate: 813273E, 818850N) was observed inside the perimeter silt curtain
of Contract HY/2010/02 on 1 July 2013, as such the original impact water
quality monitoring location at IS(Mf)9 was temporarily shifted outside the silt
curtain. As advised by the
Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted
to facilitate safe anchorage zone of construction barges/vessels until end of
2013 subject to construction progress.
Therefore, water quality monitoring station IS(Mf)9
was shifted to 813226E and 818708N since 1 July 2013. According to the water quality
monitoring team¡¦s observation on 24 March 2014, the original monitoring
location of IS(Mf)9 was no longer enclosed by the perimeter
silt curtain of Contract HY/2010/02. Thus, the impact water quality monitoring
works at the original monitoring location of IS(Mf)9
has been resumed since 24 March 2014.
Transect lines 1, 2, 7, 8, 9 and 11 for dolphin
monitoring have been revised due to the obstruction of the permanent structures
associated with the construction works of HKLR and the southern viaduct of
TM-CLKL, as well as provision of adequate buffer distance from the Airport
Restricted Areas. The EPD issued a
memo and confirmed that they had no objection on the revised transect lines on
19 August 2015.
The water quality monitoring stations at IS10
(Coordinate: 812577E, 820670N) and SR5 (811489E, 820455N) are located inside
Hong Kong International Airport (HKIA) Approach Restricted Areas. The
previously granted Vessel's Entry Permit for accessing stations IS10 and SR5
were expired on 31 December 2016. During the permit renewing process, the water
quality monitoring location was shifted to IS10(N)
(Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E, 820978N) on 2,
4 and 6 January 2017 temporarily. The permit has been granted by Marine
Department on 6 January 2017. Thus, the impact water quality monitoring works
at original monitoring location of IS10 and SR5 has been resumed since 9
January 2017.
Transect lines 2, 3, 4, 5, 6 and 7 for dolphin
monitoring have been revised and transect line 24 has been added due to the
presence of a work zone to the north of the airport platform with intense
construction activities in association with the construction of the third
runway expansion for the Hong Kong International Airport. The EPD issued a memo
and confirmed that they had no objection on the revised transect lines on 28
July 2017. The alternative dolphin transect lines are adopted starting from
August¡¦s dolphin monitoring.
A new water quality monitoring team has been
employed for carrying out water quality monitoring work for the Contract
starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong
International Airport into a Three-Runway System (3RS Project), original
locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed
by works boundary of 3RS Project. Alternative impact water quality monitoring
stations, naming as CS2(A), SR5(N) and IS10(N) was
approved on 28 July 2017 and were adopted starting from 23 August 2017 to
replace the original locations of water quality monitoring for the Contract.
The 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 is in progress.
The role and responsibilities as the ET Leader
of the Contract has been temporarily taken up by Mr Willie Wong instead of Ms
Claudine Lee since 25 September 2017.
Water quality monitoring station SR10A(N) (Coordinate: 823644E, 823484N) was unreachable on 4
October 2017 during flood tide as fishing activities were observed. As such,
the water monitoring at station SR10A(N) was conducted
at Coordinate: 823484E, 823593N during flood tide on 4 October 2017
temporarily.
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. Figure 1.1
shows the project site boundary.
1.1.5 This
is the twenty-first 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 to 30 November 2017.
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
|
Stockpiling
|
WA7
|
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
|
Excavation for HKBCF to Airport Tunnel & construction of tunnel
box structure
|
Portion X
|
Works for diversion
|
Airport Road
|
Utilities detection
|
Airport Road/ Airport Express Line/ East Coast Road
|
Establishment of site access
|
Airport Road/ Airport Express Line/ East Coast Road
|
Mined tunnel lining / box jacking transition zone rebar fixing
underneath Airport Road and Airport Express Line
|
Airport Road and Airport Express Line
|
Construction of Tunnel Box Structure
|
Shaft 3 Extension North Shaft
|
Excavation and lateral support works & Construction of Tunnel Box
Structure for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)
|
Airport Road
|
Excavation and lateral support works & construction of tunnel box
structure for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)
|
Portion X
|
Sub-structure, superstructure and finishing works for Highway
Operation and Maintenance Area Building
|
Portion X
|
Superstructure and Finishing works for Scenic Hill Tunnel West Portal
Ventilation Building
|
West Portal
|
2.1
Summary of
EM&A Requirements
2.1.1
The EM&A programme requires environmental
monitoring of air quality, noise, water quality, dolphin monitoring and mudflat
monitoring as specified in the approved EM&A Manual.
2.1.2
A summary of Impact EM&A requirements is
presented in Table 2.1. The locations of air quality, noise and water quality monitoring
stations are shown as in Figure 2.1. The transect line layout in Northwest and
Northeast Lantau Survey Areas is presented in Figure 2.2.
Table 2.1 Summary
of Impact EM&A Requirements
Environmental
Monitoring
|
Description
|
Monitoring
Station
|
Frequencies
|
Remarks
|
Air Quality
|
1-hr TSP
|
AMS 5 & AMS
6
|
At least 3 times every 6 days
|
While the
highest dust impact was expected.
|
24-hr TSP
|
At least once every 6 days
|
--
|
Noise
|
Leq (30mins),
L10 (30mins) and
L90 (30mins)
|
NMS 5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡P Depth
¡P Temperature
¡P Salinity
¡P Dissolved Oxygen
(DO)
¡P Suspended Solids
(SS)
¡P DO Saturation
¡P Turbidity
¡P pH
|
¡P Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,
¡P Control/Far Field
Stations:
CS2 & CS(Mf)5,
¡P Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A & SR10B
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 1.75 hour of the predicted time)
|
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth be less than 3
m, only the mid-depth station will be monitored).
|
Dolphin
|
Line-transect Methods
|
Northeast Lantau survey
area and Northwest Lantau survey area
|
Twice
per month
|
--
|
Mudflat
|
Horseshoe crabs, seagrass beds, intertidal soft shore communities,
sedimentation rates and water quality
|
San Tau and Tung Chung Bay
|
Once every 3 months
|
--
|
2.2.1
Table 2.2 presents
the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.
Table 2.2 Action
and Limit Levels for 1-hour TSP, 24-hour TSP and Noise
Environmental Monitoring
|
Parameters
|
Monitoring Station
|
Action Level
|
Limit Level
|
Air
Quality
|
1-hr
TSP
|
AMS
5
|
352 µg/m3
|
500 µg/m3
|
AMS
6
|
360 µg/m3
|
24-hr
TSP
|
AMS
5
|
164 µg/m3
|
260 µg/m3
|
AMS
6
|
173 µg/m3
|
Noise
|
Leq
(30 min)
|
NMS 5
|
When
one documented complaint is received
|
75
dB(A)
|
2.2.2
The Action and
Limit Levels for water quality monitoring are given as in Table 2.3.
Table 2.3 Action
and Limit Levels for Water Quality
Parameter
(unit)
|
Water Depth
|
Action
Level
|
Limit Level
|
Dissolved Oxygen (mg/L)
|
Surface and Middle
|
5.0
|
4.2 except 5 for Fish
Culture Zone
|
Bottom
|
4.7
|
3.6
|
Turbidity (NTU)
|
Depth average
|
27.5 or 120% of upstream
control station¡¦s turbidity at the same tide of the same day;
The action level has been
amended to ¡§27.5 and 120% of upstream control station¡¦s turbidity at the same
tide of the same day¡¨ since 25 March 2013.
|
47.0 or 130% of turbidity at
the upstream control station at the same tide of same day;
The limit level has been
amended to ¡§47.0 and 130% of turbidity at the upstream control station at the
same tide of same day¡¨ since 25 March 2013.
|
Suspended Solid (SS)
(mg/L)
|
Depth average
|
23.5 or 120% of upstream
control station¡¦s SS at the same tide of the same day;
The action level has been
amended to ¡§23.5 and 120% of upstream control station¡¦s SS at the same tide of
the same day¡¨ since 25 March 2013.
|
34.4 or 130% of SS at the
upstream control station at the same tide of same day and 10mg/L for Water
Services Department Seawater Intakes;
The limit level has been
amended to ¡§34.4 and 130% of SS at the upstream control station at the same
tide of same day and 10mg/L for Water Services Department Seawater Intakes¡¨
since 25 March 2013
|
Notes:
(1) Depth-averaged is
calculated by taking the arithmetic means of reading of all three depths.
(2) For DO, non-compliance
of the water quality limit occurs when monitoring result is lower that the
limit.
(3) For SS & turbidity
non-compliance of the water quality limits occur when monitoring result is
higher than the limits.
(4) The change to the
Action and limit Levels for Water Quality Monitoring for the EM&A works was
approved by EPD on 25 March 2013. Therefore, the amended Action and Limit
Levels are applied for the water monitoring results obtained on and after 25
March 2013.
2.2.3
The Action and
Limit Levels for dolphin monitoring are shown in Tables 2.4 and 2.5.
Table 2.4 Action
and Limit Level for Dolphin Impact Monitoring
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
Limit Level
|
STG < 40% of baseline
&
ANI < 40% of baseline
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
Table 2.5 Derived
Value of Action Level (AL) and Limit Level (LL)
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 4.2 & ANI
< 15.5
|
STG < 6.9 & ANI
< 31.3
|
Limit Level
|
(STG < 2.4 & ANI
< 8.9) and (STG < 3.9 & ANI < 17.9)
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
2.3.1
The Event Actions Plans for air quality, noise,
water quality and dolphin monitoring are annexed in Appendix D.
2.4.1 Environmental mitigation
measures for the contract were recommended in the approved EIA Report. Appendix E lists the recommended
mitigation measures and the implementation status.
3
Environmental
Monitoring and Audit
3.1
Implementation
of Environmental Measures
3.1.1
In response to the site audit findings, the
Contractor have rectified all observations identified
in environmental site inspections undertaken during the reporting period.
Details of site audit findings and the corrective actions during the reporting
period are presented in Appendix F.
3.1.2
A summary of the Implementation Schedule of
Environmental Mitigation Measures (EMIS) is presented in Appendix E.
3.1.3 Regular
marine travel route for marine vessels were implemented properly in accordance
to the submitted plan and relevant records were kept properly.
3.1.4 Dolphin
Watching Plan was implemented during the reporting period.
No dolphins inside the silt curtain were observed. The relevant records were
kept properly.
3.2.1 The
monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2
respectively. Detailed impact air quality monitoring results and relevant
graphical plots are
presented in Appendix G.
Table 3.1 Summary
of 1-hour TSP Monitoring Results Obtained During the
Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
September 2017
|
AMS5
|
53
|
5 ¡V 302
|
352
|
500
|
AMS6
|
40
|
10 ¡V 151
|
360
|
October 2017
|
AMS5
|
36
|
12 ¡V 61
|
352
|
AMS6
|
41
|
25 ¡V 69
|
360
|
November 2017
|
AMS5
|
47
|
22 ¡V 72
|
352
|
AMS6
|
59
|
23 ¡V 109
|
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)
|
September 2017
|
AMS5
|
40
|
22 ¡V 71
|
164
|
260
|
AMS6
|
48
|
31 ¡V 72
|
173
|
October 2017
|
AMS5
|
74
|
48 ¡V 100
|
164
|
AMS6
|
110
|
73 ¡V 163
|
173
|
November 2017
|
AMS5
|
72
|
30 ¡V 110
|
164
|
AMS6
|
105
|
71 ¡V 136
|
173
|
3.2.2
No Action Level and
Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS5 and
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)
|
September 2017
|
NMS5
|
58
|
56 ¡V 70
|
When one documented complaint is received
|
75
|
October 2017
|
59
|
58 ¡V 60
|
November 2017
|
59
|
58 ¡V 59
|
*A correction factor of +3dB(A) from free field to facade measurement was included.
3.3.2
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
3.3.3 Major
noise sources during the noise monitoring included construction activities of
the Contract and nearby traffic noise and insect noise.
3.4.1 Impact
water quality monitoring was conducted at all designated monitoring stations
during the reporting period. Impact water quality monitoring results and
relevant graphical plots are provided in Appendix I.
3.4.1
3.4.2
No Action Level and Limit Level exceedances for
turbidity level and dissolved oxygen level were recorded during the reporting
period. There were 17 Action Level exceedances and 3 Limit Level exceedances of
suspended solids level during the reporting period. The exceedances of
suspended solids level recorded during reporting period were considered to be
attributed to other external factors such as sea condition, rather than the
contract works. The exceedances were considered as non-contract related. Record
of ¡§Notification of Environmental Quality Limit Exceedances¡¨ is provided in Appendix M.
3.4.3
Water quality impact sources during the water
quality monitoring were the construction activities of the Contract, nearby
construction activities by other parties and nearby operating vessels by other
parties.
Data
Analysis
3.5.1 Distribution Analysis ¡V The line-transect survey data was integrated with the
Geographic Information System (GIS) in order to visualize and interpret
different spatial and temporal patterns of dolphin distribution using sighting
positions. Location data of dolphin
groups were plotted on map layers of Hong Kong
using a desktop GIS (ArcView© 3.1) to examine their distribution
patterns in details. The dataset was also stratified into different subsets to
examine distribution patterns of dolphin groups with different categories of
group sizes, young calves and activities.
3.5.2
Encounter rate analysis ¡V Encounter rates of
Chinese white dolphins (number of on-effort sightings per 100 km of survey
effort, and total number of dolphins sighted on-effort per 100 km of survey
effort) were calculated in NEL and NWL survey areas in relation to the amount
of survey effort conducted during each month of monitoring survey. Dolphin encounter rates were calculated
in two ways for comparisons with the HZMB baseline monitoring results as well
as to AFCD long-term marine mammal monitoring results.
3.5.3
Firstly, for the comparison with the HZMB
baseline monitoring results, the encounter rates were calculated using primary
survey effort alone, and only data collected under Beaufort 3 or below
condition would be used for encounter rate analysis. The average encounter rate of sightings
(STG) and average encounter rate of dolphins (ANI) were deduced based on the
encounter rates from six events during the present quarter (i.e. six sets of
line-transect surveys in North Lantau), which was also compared with the one
deduced from the six events during the baseline period (i.e. six sets of
line-transect surveys in North Lantau).
3.5.4
Secondly, the encounter rates were calculated
using both primary and secondary survey effort collected under Beaufort 3 or
below condition as in AFCD long-term monitoring study. The encounter rate of sightings and
dolphins were deduced by dividing the total number of on-effort sightings (STG)
and total number of dolphins (ANI) by the amount of survey effort for the
present quarterly period.
3.5.5
Quantitative grid analysis on habitat use ¡V To
conduct quantitative grid analysis of habitat use, positions of on-effort
sightings of Chinese White Dolphins collected during the quarterly impact phase
monitoring period were plotted onto 1-km2 grids among NWL and NEL
survey areas on GIS. Sighting
densities (number of on-effort sightings per km2) and dolphin densities
(total number of dolphins from on-effort sightings per km2) were
then calculated for each 1 km by 1 km grid with the aid of GIS. Sighting density grids and dolphin
density grids were then further normalized with the amount of survey effort
conducted within each grid. The
total amount of survey effort spent on each grid was calculated by examining
the survey coverage on each line-transect survey to determine how many times
the grid was surveyed during the study period. For example, when the survey boat
traversed through a specific grid 50 times, 50 units of survey effort were
counted for that grid. With the
amount of survey effort calculated for each grid, the sighting density and
dolphin density of each grid were then normalized (i.e. divided by the unit of
survey effort).
3.5.6 The
newly-derived unit for sighting density was termed SPSE, representing the
number of on-effort sightings per 100 units of survey effort. In addition, the derived unit for actual
dolphin density was termed DPSE, representing the number of dolphins per 100
units of survey effort. Among the
1-km2 grids that were partially covered by land, the percentage of
sea area was calculated using GIS tools, and their SPSE and DPSE values were
adjusted accordingly. The following
formulae were used to estimate SPSE and DPSE in each 1-km2 grid
within the study area:
SPSE = ((S / E) x 100) /
SA%
DPSE = ((D / E) x 100) /
SA%
where S =
total number of on-effort sightings
D = total number of
dolphins from on-effort sightings
E = total number of units
of survey effort
SA% = percentage of sea
area
3.5.7 Behavioural
analysis ¡V When dolphins were sighted during vessel surveys, their behaviour
was observed. Different activities
were categorized (i.e. feeding, milling/resting, traveling, socializing) and
recorded on sighting datasheets.
This data was then input into a separate database with sighting
information, which can be used to determine the distribution of behavioural
data with a desktop GIS.
Distribution of sightings of dolphins engaged in different activities
and behaviours would then be plotted on GIS and carefully examined to identify
important areas for different activities of the dolphins.
3.5.8 Ranging
pattern analysis ¡V Location data of individual dolphins that occurred during
the 3-month baseline monitoring period were obtained from the dolphin sighting
database and photo-identification catalogue. To deduce home ranges for individual
dolphins using the fixed kernel methods, the program Animal Movement Analyst
Extension, was loaded as an extension with ArcView© 3.1 along with
another extension Spatial Analyst 2.0.
Using the fixed kernel method, the program calculated kernel density
estimates based on all sighting positions, and provided an active interface to
display kernel density plots. The
kernel estimator then calculated and displayed the overall ranging area at 95%
UD level.
Summary
of Survey Effort and Dolphin Sightings
3.5.9
During the period
of September
to November 2017, 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 802.12 km of survey effort was collected, with 96.0% of the
total survey effort being conducted under favourable weather conditions (i.e.
Beaufort Sea State 3 or below with good visibility). Among the two areas, 297.00 km and 505.12 km of survey effort were conducted in NEL and NWL survey areas
respectively.
3.5.11
The total survey
effort conducted on primary lines 578.16 km, while the effort on secondary lines was 223.96 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 Annex I of Appendix J.
3.5.12
During the six
sets of monitoring surveys in September to November 2017, 13 groups of 50 Chinese
White Dolphins were sighted, with the summary
table of the dolphin sightings is shown in Annex
II of Appendix J. All dolphin sightings were made during on-effort search, while 12 of the 13 on-effort dolphin sightings
were made on
primary lines. 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
3.5.13
Distribution of dolphin sightings made during
monitoring surveys in September to November 2017 is shown in
Figure 1 of Appendix J. Almost all sightings were made at the northwest portion of the North
Lantau region, mainly to the east of Lung Kwu Chau and at the mouth of Deep Bay
near Black Point (Figure 1 of Appendix J). One dolphin group was also sighted at the southwestern end of NWL survey
area, or near the HKLR09 alignment.
As consistently recorded in the previous monitoring quarters, the
dolphins were completely absent from the central and eastern portions of North
Lantau waters
(Figure 1 of Appendix J).
3.5.14
All
dolphin sightings were located far away from the HKLR03 and HKBCF reclamation
sites as well as along the alignment and Tuen Mun-Chek Lap Kok Link (TMCLKL) (Figure 1 of Appendix J). However, one sighting was made near the
alignment of HKLR09 as mentioned above.
3.5.15 Sighting
distribution of dolphins during the present impact phase monitoring period
(September to November 2017) 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 18 quarters of HKLR03
monitoring, which has resulted in zero to extremely low dolphin encounter rates
in this area.
3.5.16
In NWL
survey area, dolphin
occurrence was also significantly different between the baseline and impact
phase periods. During the present
impact monitoring period, dolphins were infrequently sighted here, and mainly at
the northwestern end of the area, which was in stark contrast with their
frequent occurrences throughout the area during the baseline period (Figure 1
of Appendix J).
3.5.17
Another
comparison in dolphin distribution was made between the five quarterly periods
of autumn months in 2013-17 (Figure 2 of
Appendix J). Among the
five autumn periods, dolphins were still sighted regularly in NWL waters in
2013 and 2014, but their usage there was progressively reduced in the three
subsequent autumn periods, with the only occurrences mostly concentrated at the
northwestern portion of the survey area (Figure 2 of Appendix J).
Encounter Rate
3.5.18
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).
3.5.19 To facilitate the comparison with
the AFCD long-term monitoring results, the encounter rates were also calculated
for the present quarter using both primary and secondary survey effort. The encounter rates of sightings (STG)
and dolphins (ANI) in NWL were 2.5 sightings and 9.9 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 to November 2017)
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 (15 & 18 Sep 2017)
|
0.00
|
0.00
|
Set 2 (22 & 29 Sep 2017)
|
0.00
|
0.00
|
Set 3 (4 & 9 Oct
2017)
|
0.00
|
0.00
|
Set 4 (18 & 26 Oct 2017)
|
0.00
|
0.00
|
Set 5 (1
& 8 Nov
2017)
|
0.00
|
0.00
|
Set 6 (17 & 24 Nov 2017)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (15 & 18 Sep 2017)
|
0.00
|
0.00
|
Set 2 (22 & 29 Sep 2017)
|
3.63
|
16.34
|
Set 3 (4 & 9 Oct
2017)
|
1.86
|
9.30
|
Set 4 (18 & 26 Oct 2017)
|
4.89
|
4.89
|
Set 5 (1
& 8 Nov
2017)
|
4.99
|
26.60
|
Set 6 (17 & 24 Nov 2017)
|
3.33
|
5.00
|
Table
3.5 Comparison of average dolphin encounter rates from impact
monitoring period (September to November 2017) 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
|
3.12 ¡Ó
1.91
|
9.85 ¡Ó 5.85
|
10.35 ¡Ó 9.66
|
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.
3.5.20
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
18 quarters of HKLR03 monitoring (Table
3.6). This is a serious concern as the dolphin
occurrence in NEL in the past few years (0.0-1.0 for ER(STG) and 0.0-3.9 for
ER(ANI)) have remained exceptionally low when compared to the baseline period (Table 3.6). Dolphins have been virtually absent from NEL waters since January 2014,
with only three groups of six dolphins sighted there since then despite
consistent and intensive survey effort being conducted in this survey area.
Table
3.6 Comparison of Average
Dolphin Encounter Rates in Northeast Lantau Survey Area from All Quarters of
Impact Monitoring Period and Baseline Monitoring Period (Sep ¡V Nov 2011)
Monitoring Period
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
September-November 2011 (Baseline)
|
6.00 ¡Ó 5.05*
|
22.19 ¡Ó
26.81*
|
December
2012-February
2013 (Impact)
|
3.14
¡Ó 3.21
|
6.33
¡Ó 8.64
|
March-May 2013
(Impact)
|
0.42
¡Ó 1.03
|
0.42
¡Ó 1.03
|
June-August 2013
(Impact)
|
0.88
¡Ó 1.36
|
3.91
¡Ó 8.36
|
September-November
2013 (Impact)
|
1.01 ¡Ó 1.59*
|
3.77 ¡Ó 6.49*
|
December
2013-February
2014 (Impact)
|
0.45
¡Ó 1.10
|
1.34
¡Ó 3.29
|
March-May 2014
(Impact)
|
0.00
|
0.00
|
June-August 2014
(Impact)
|
0.42
¡Ó 1.04
|
1.69
¡Ó 4.15
|
September-November 2014 (Impact)
|
0.00*
|
0.00*
|
December
2014-February
2015 (Impact)
|
0.00
|
0.00
|
March-May 2015
(Impact)
|
0.00
|
0.00
|
June-August 2015
(Impact)
|
0.44
¡Ó 1.08
|
0.44
¡Ó 1.08
|
September-November 2015 (Impact)
|
0.00*
|
0.00*
|
December
2015-February
2016 (Impact)
|
0.00
|
0.00
|
March-May 2016
(Impact)
|
0.00
|
0.00
|
June-August 2016
(Impact)
|
0.00
|
0.00
|
September-November 2016 (Impact)
|
0.00*
|
0.00*
|
December
2016-February
2017 (Impact)
|
0.00
|
0.00
|
March-May 2017
(Impact)
|
0.00
|
0.00
|
June-August 2017
(Impact)
|
0.00
|
0.00
|
September-November 2017 (Impact)
|
0.00*
|
0.00*
|
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
autumnr months were in blue and marked with asterisk.
3.5.21
On the
other hand, the
average dolphin encounter rates (STG and ANI) in NWL during the present impact
phase monitoring period (reductions of 68.3% and 76.8% respectively) were only
small fractions of the ones recorded during the three-month baseline period,
indicating a dramatic decline in dolphin usage of this survey area as well
during the present impact phase period (Table 3.7).
3.5.22
Dolphin
encounter rates in NWL during autumn 2017 was similar to the previous autumn
period in 2016, but was much lower than the ones in the autumn periods of 2013,
2014 and 2015 (Table 3.7). Such temporal trend should be closely
monitored in the upcoming monitoring quarters whether the dolphin occurrence
would continue to increase as the construction activities of HZMB works have
been mostly completed in coming months.
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*
|
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
As
discussed in Hung (2017), the dramatic decline in dolphin usage of NEL waters
in the past few years (including the declines in abundance, encounter rate and
habitat use in NEL, as well as shifts of individual core areas and ranges away
from NEL waters) was possibly related to the HZMB construction works that were
commenced since 2012. Apparently
such noticeable decline has already extended to NWL waters progressively in the
past few years with no sign of recovery, even though the HZMB-related
construction activities have well past the peak.
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 (20th
quarter of the impact phase being assessed), the p-values for the differences
in average dolphin encounter rates of STG and ANI were 0.0057 and 0.0278 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 20 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, and such low occurrence of dolphins has also been
consistently documented in previous quarters of the past few years.
3.5.28
The dramatic decline in dolphin usage of North Lantau
region raises serious concern, as the timing of the decline in dolphin usage in
North Lantau waters coincided well with the
construction schedule of the HZMB-related projects (Hung 2017). Apparently there was no 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 12 individuals per group in North Lantau
region during September to November 2017. 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 ¡V Nov 2017) and
Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average
Dolphin Group Size
|
Reporting
Period
|
Baseline
Monitoring Period
|
Overall
|
3.85
¡Ó 3.39 (n = 13)
|
3.72
¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
3.85 ¡Ó 3.39 (n = 12)
|
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 2017 was only slightly higher than the one recorded
during the three-month baseline period, but it should also be noted that the
sample size of 13 dolphin groups in the present quarter was very small when
compared to the 66 groups sighted during the baseline period(Table 3.8).
3.5.31 Notably, 8 of these 14 dolphin groups were composed of
1-3 individuals only while there were four medium-sized groups
with 5-8 dolphins per group, and one large group of 12 dolphins (Annex II of Appendix J).
3.5.32
Distribution
of the larger dolphin groups with five individuals or more per group during the
present quarter is shown in Figure 3 of Appendix J, with comparison to the one in baseline
period. The
medium-sized group with 5-8 dolphins were scattered at the northwestern portion
of the NWL survey area with no particular concentration, while the one large
group of 12 dolphins was sighted at the mouth of Deep Bay (Figure 3 of
Appendix J). Such
distribution pattern was very different from the baseline period, when the
larger dolphin groups were frequently sighted and evenly distributed in NWL
waters, and a few were also sighted in NEL waters (Figure 3 of
Appendix J).
Habitat Use
3.5.33
From September to November 2017, four of the five grids with moderately high to high
dolphin densities were located to the north of Lung Kwu Chau, while one grid to
the east of Sha Chau also recorded moderately high dolphin density (Figures 4a and 4b of Appendix J). All grids near HKLR03/HKBCF reclamation sites as well as TMCLKL
alignment did not record any presence of dolphins at all during on-effort
search in the present quarterly period (Figures 4a and 4b of Appendix J).
3.5.34 However, it should be emphasized that the
amount of survey effort collected in each grid during the three-month period
was fairly low (6-12 units of survey effort for most grids), and therefore the
habitat use pattern derived from the three-month dataset should be treated with
caution. A more complete picture of dolphin habitat use pattern should be examined when more survey effort for each grid will be
collected throughout the impact phase monitoring programme.
3.5.35
When compared with the habitat use patterns during
the baseline period, dolphin usage in NEL and NWL has drastically diminished in
both areas during the present impact monitoring period (Figure 5 of
Appendix J). During the baseline period, many grids between Siu
Mo To and Shum Shui Kok in NEL recorded moderately high to high dolphin
densities, which was in stark contrast to the complete absence of dolphins
there during the present impact phase period (Figure 5 of
Appendix J).
3.5.36
The density patterns were also very different in
NWL between the baseline and impact phase monitoring periods, with high dolphin
usage throughout the area, especially around Sha Chau, near Black Point, to the
west of the airport, as well as between Pillar Point and airport platform
during the baseline period. In
contrast, only several grids with moderately high to high dolphin densities
were located near Lung Kwu Chau and Sha Chau during the present impact phase
period(Figure 5 of Appendix J).
Mother-calf Pairs
3.5.37
During the present quarterly period, no young
calf was sighted at all among the 13 groups of dolphins.
Activities and Associations with Fishing Boats
3.5.38
One of the thirteen dolphin groups were engaged in
feeding activity, while another two groups were engaged in socializing
activity. However, none of them was
engaged in traveling or milling/resting activity during the three-month study period.
3.5.39 The
percentages of sightings associated with feeding activities (7.7%) was lower
than the one recorded during the baseline period (11.6%), while the one for
socializing activities (15.4%) was much higher than the ones recorded during
the baseline period (5.4% respectively). However, it should be noted the sample
sizes on total numbers of dolphin sightings were very different between the two
periods.
3.5.40 Distribution
of dolphins engaged in various activities during the present three-month period and
baseline period is shown in
(Figure
6 of Appendix J). The one dolphin group engaged in feeding activity
was sighted at the southeast corner of Lung Kwu Chau, while the two dolphin
groups engaged in socializing activities were both located to the north of Lung
Kwu Chau (Figure 6 of Appendix J).
3.5.41 When compared to
the baseline period, distribution of various dolphin activities during the
present impact phase monitoring period was drastically different with a much
more restricted area of occurrences (Figure 6 of Appendix J).
3.5.42 Notably,
one group of a single dolphin was found to be associated with an operating
purse-seiner adjacent to Lung Kwu Chau within the marine park during the present
impact phase period.
Summary Photo-identification works
3.5.43
From September to
November 2017, over 2,500 digital photographs of Chinese White Dolphins were
taken during the impact phase monitoring surveys for the photo-identification
work.
3.5.44
In total, 23 individuals sighted 42 times altogether were identified
(see summary table in Annex III of Appendix J and photographs of
identified individuals in Annex IV of
Appendix J). All of these
re-sightings were made in NWL. (i.e. CH34, NL33, NL46, NL49, NL320,
NL322, NL328 and WL05) were re-sighted twice, while four other individuals
(i.e. NL136, NL182, NL202 and NL286) were re-sighted 3-4 times during the
three-month period (Annex III of Appendix J).
3.5.45
Notably, ten of these 23 individuals (i.e. CH34, NL12, NL49,
NL104, NL136, NL182, NL202, NL320, NL321 and WL05) were also sighted in Northwest Lantau during the HKBCF monitoring surveys
under the same three-month period.
Moreover, six individuals (i.e. CH34, NL12, NL49, NL182, NL210 and WL05)
were also sighted in West Lantau waters during the HKLR09 monitoring surveys
from September to November 2017, showing their extensive individual movements
across different survey areas.
Individual range use
3.5.46
Ranging patterns of the 23 individuals
identified during the three-month study period were determined by fixed kernel
method, and are shown in Annex V of Appendix J.
3.5.47
All identified dolphins sighted in the present
quarter were utilizing NWL waters only, but have completely avoided NEL waters
where many of them have utilized as their core areas in the past (Annex V of
Appendix J). This is in
contrary to the extensive movements between NEL and NWL survey areas observed
in the earlier impact monitoring quarters as well as the baseline period.
3.5.48
On the other hand, three individuals (i.e. NL12,
NL182 and NL210) consistently utilized North Lantau waters in the past have
extended their range use to WL during the present quarter.
3.5.49
In the upcoming quarters, individual range use
and movements should be continuously monitored to examine whether there has
been any consistent shifts of individual home ranges from North Lantau to West
or Southwest Lantau, as such shift could possibly be related to the
HZMB-related construction works (see Hung 2017).
Action Level / Limit Level Exceedance
3.5.50
There was one Limit Level exceedance of dolphin
monitoring for the quarterly monitoring data (between September 2017 ¡V November
2017). According to the contractor¡¦s information, the marine activities
undertaken for HKLR03 during the quarter of September 2017 ¡V November 2017
included seawall construction, box culvert construction, road and drainage
construction and road and drainage works.
3.5.51
There is no evidence
showing the current LL non-compliance directly related to the construction
works of HKLR03 (where the amounts of working vessels for HKLR03 have been
decreasing), although the generally increased amount of vessel traffic in NEL
during the impact phase has been partly contributed by HKLR03 works since
October 2012. It should also be noted that reclamation work under HKLR03
(adjoining the Airport Island) situates in waters which has rarely been used by
dolphins in the past, and the working vessels under HKLR03 have been travelling
from source to destination in accordance with the Marine Travel Route to
minimize impacts on Chinese White Dolphin (CWD). In addition, the contractor will implement
proactive mitigation measures such as avoiding anchoring at Marine Department¡¦s
designated anchorage site ¡V Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable.
3.5.52
According to Monitoring
of Chinese White Dolphins in Southwest Lantau Waters ¡V Fourth Quarterly Report
(December 2015 to February 2016) which is available on ENPO¡¦s website, with
their primary ranges centered in North and West Lantau waters, some individuals
showed apparent range shifts or extensions to Southwest Lantau waters in
2015-16. For example, three
individual dolphins (NL120, WL46 and WL221) indicated obvious shifts in their
range use from NWL to West Lantau (WL) and Southwest Lantau (SWL) waters.
Moreover, many individuals (e.g. NL212, NL260, WL200, SL55, WL232, WL237 and
WL265) have extended their ranges from WL waters to SWL waters. It remains to be seen whether some of
these individuals have permanently shifted their ranges away from their primary
ranges in North Lantau, or begin to spend more times in SWL waters as part of
their ranges.
3.5.53 ENPO updated that the Hong Kong-Zhuhai-Macao Bridge Authority (HZMBA) for
the Mainland section of Hong Kong-Zhuhai-Macao Bridge (HZMB) has commenced an
interim survey on fisheries resources and CWD in the Mainland waters. ENPO
presented the preliminary findings of the HZMBA interim survey on CWD sighting
and photo-identification works which provide solid evidence that some CWD that
were previously more often sighted in HK waters have expanded their ranges into
the Mainland waters, and some with reduced usage in HK waters. These
preliminary data were mentioned in Monitoring of Chinese White Dolphins in
Southwest Lantau Waters ¡V Fourth Quarterly Report (December 2015 to February
2016) which is available on ENPO¡¦s website.
3.5.54
A two-way ANOVA with
repeated measures and unequal sample size was conducted to examine whether
there were any significant differences in the average encounter rates between
the baseline and impact monitoring periods. The two variables that were examined
included the two periods (baseline and impact phases) and two locations (NEL
and NWL).
3.5.55
For the comparison between the baseline period
and the present quarter (20th quarter of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.0057 and 0.0278 respectively. If the alpha value is set at 0.05,
significant differences were detected between the baseline and present quarters
in both the average dolphin encounter rates of STG and ANI.
3.5.56
For the comparison between the baseline period
and the cumulative quarters in impact phase (i.e. first 20 quarters of the
impact phase being assessed), the p-values for the differences in average
dolphin encounter rates of STG and ANI were 0.000000 and 0.000000
respectively. Even if the alpha
value is set at 0.00001, significant differences were still detected in both
the average dolphin encounter rates of STG and ANI (i.e. between the two
periods and the locations).
3.5.57
The AFCD monitoring data
during September 2017 to November 2017 has been reviewed by the dolphin specialist. During the same quarter, no dolphin was
sighted from 74.65 km of survey effort on primary lines in NEL, while four
groups of 18 dolphins were sighted from 133.52 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 2017 in NEL and NWL survey
area is accurate.
3.5.58
All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Marine Travel Route Plan, the travelling speed of
vessels must not exceed 5 knots when crossing the edge of the proposed marine
park. The Contractor will continue to provide training for skippers to ensure
that their working vessels travel from source to destination to minimize
impacts on Chinese White Dolphin and avoid anchoring at Marine Department¡¦s
designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
3.5.59 All dolphin protective measures are fully and properly implemented in
accordance with the EM&A Manual. According to the Marine Travel Route Plan,
the travelling speed of vessels must not exceed 5 knots when crossing the edge
of the proposed marine park. The Contractor will continue to provide training
for skippers to ensure that their working vessels travel from source to destination
to minimize impacts on Chinese White Dolphin and avoid anchoring at Marine
Department¡¦s designated anchorage site - Sham Shui Kok Anchorage (near Brothers
Island) as far as practicable. Also, it is recommended to complete the marine
works of the Contract as soon as possible so as to reduce the overall duration
of impacts and allow the dolphins population
to recover as early as possible.
3.5.60 A meeting was held on 7 March
2018 with attendance of representative of ENPO, Resident Site Staff (RSS),
Environmental Team (ET) and dolphin specialist for Contract Nos. HY/2013/01,
HY/2011/03, HY/2011/09, HY/2012/07, HY/2012/08. The discussion/ recommendation
as raised in the meeting which might be relevant to HKLR03 Contract are
summarized below.
3.5.61
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.
3.5.62
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
apparently related to the re-routing of high speed ferry (HSF) from Skypier.
3.5.63
It was reminded that the
ETs shall keep reviewing the implementation status of the dolphin related
mitigation measures and remind the contractor to ensure the relevant measures
were fully implemented.
3.5.64
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.
3.5.65
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.
3.5.66
It was suggested that the
protection measures (e.g., speed limit control) for the proposed Brothers
Marine Park (BMP) shall be brought forward as soon as possible before its
establishment so as to provide a better habitat for dolphin recovery. It was
noted that under the Regular Marine Travel Route Plan, the contractors have committed
to reduce the vessel speed in BMP. HyD updated that the draft map of the
proposed 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 RMTR Plan. The BMP was
designated on 30 December 2016. It
was reminded that trespassing the BMP is not allowed under the RMTR Plan.
3.5.67
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 16 September 2017. 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 2017)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.088
|
816678.776
|
1.088
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.265
|
815831.586
|
0.973
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.480
|
815953.308
|
1.463
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.423
|
816151.385
|
1.085
|
Table 3.10 Comparison
of Measurement
|
Comparison of
measurement
|
Remarks and Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
-0.072
|
0.049
|
0.138
|
Level continuously increased
|
S2
|
-0.007
|
0.055
|
0.109
|
Level continuously increased
|
S3
|
-0.105
|
0.000
|
0.122
|
Level continuously increased
|
S4
|
-0.01
|
0.004
|
0.154
|
Level continuously increased
|
3.6.2
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2,
S3 and S4. The mudflat level is continuously increased.
Water
Quality Monitoring
3.6.3
The mudflat monitoring covered water quality
monitoring data. Reference was made
to the water quality monitoring data of the representative water quality
monitoring station (i.e. SR3) as in the EM&A Manual. The water quality monitoring location
(SR3) is shown in Figure 2.1.
3.6.4 Impact
water quality monitoring in San Tau (monitoring station SR3) was conducted in
September 2017. The monitoring parameters included dissolved oxygen (DO),
turbidity and suspended solids (SS).
3.6.5 The Impact monitoring result for SR3 were extracted and summarised
below:
Table 3.11 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)
|
1-Sep-17
|
6.6
|
7.4
|
4.7
|
6.9
|
6.0
|
7.0
|
4-Sep-17
|
Remark 1
|
Remark 1
|
Remark 1
|
6.0
|
8.7
|
9.7
|
6-Sep-17
|
5.5
|
11.4
|
9.1
|
5.5
|
10.3
|
9.9
|
8-Sep-17
|
6.1
|
11.4
|
7.7
|
5.6
|
5.7
|
8.0
|
11-Sep-17
|
5.7
|
6.8
|
12.1
|
5.4
|
5.4
|
11.3
|
13-Sep-17
|
5.2
|
6.6
|
6.2
|
5.8
|
11.5
|
38.7
|
15-Sep-17
|
6.2
|
5.4
|
3.5
|
6.7
|
7.8
|
4.9
|
18-Sep-17
|
6.1
|
3.6
|
6.4
|
8.3
|
6.5
|
10.1
|
20-Sep-17
|
5.9
|
12.5
|
19.1
|
5.9
|
5.6
|
11.6
|
22-Sep-17
|
11.3
|
9.3
|
12.1
|
5.3
|
7.5
|
11.9
|
25-Sep-17
|
5.7
|
5.0
|
7.8
|
5.9
|
5.8
|
7.7
|
27-Sep-17
|
6.6
|
5.9
|
8.2
|
6.0
|
2.1
|
5.7
|
29-Sep-17
|
5.9
|
4.3
|
8.0
|
8.0
|
5.5
|
9.2
|
Average
|
6.4
|
7.5
|
8.7
|
6.3
|
6.8
|
11.2
|
Remark:
1) All water quality monitoring was conducted as scheduled in
the reporting month except water quality monitoring during mid-ebb tide on 4
September 2017 which was cancelled due to adverse weather condition (Strong
Wind Signal No. 3).
|
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 2017
(totally 5 sampling days between 2nd and 17th September
2017).
3.6.7 Since the field survey of Jun. 2016,
increasing number of trashes and even big trashes (Figure 2.3 of Appendix O) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Wan. Respective measures (e.g. manual clean-up) should be
implemented by responsible units.
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 2nd (for TC2), 3rd (for TC1) and 6th (for
TC3 and ST) September 2017. The weather was generally hot on all field days
without rainfall.
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 inhabitating sub-tidal environment while it forages on intertidal
shore occasionally during high tide period. If it is tangled by the trash net
for few days, it may die due to starvation or overheat during low tide period.
These trash gill nets are definitely ¡¥fatal trap¡¦ for the horseshoe crabs and
other marine life. Manual clean-up should be implemented as soon as possible by
responsible units.
Seagrass Beds
3.6.10 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 2nd (for TC2), 3rd (for
TC1) and 6th (for TC3 and ST) September 2017. The weather was
generally hot on all field days without rainfall.
Intertidal Soft Shore
Communities
3.6.11 The intertidal
soft shore community surveys were conducted in low tide period on 2nd
(for TC2), 3rd (for TC1), 16th (for TC3) and 17th
(for ST) September 2017. 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).
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 130 ind.) and Tachypleus
tridentatus (total 77 ind.) were recorded. For one sight record, grouping
of 2-18 individuals was observed at same locations with 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, moderate
number of individuals (18 ind.) were found in TC1 that search record was at
low-moderate level (4.5 ind. hr-1 person-1). The average
body size was 30.91 mm (prosomal width ranged 19.99-47.55 mm) in TC1. There was
one individual found in TC2 only (prosomal width 37.85 mm) resulting in very
low search record (0.3 ind. hr-1 person-1). More
individuals were found in TC3 (72 ind.) and ST (39 ind.) resulting in
relatively higher search records (6.5-12.0 ind. hr-1 person-1).
Smaller individuals were found in TC3 that the average body size was 35.02 mm
(prosomal width ranged 13.30-80.27 mm). The average body size was 50.18 mm (prosomal
width ranged 19.87-78.00 mm) in ST.
3.6.18 For Tachypleus tridentatus, there was one
individual found in TC1 only (prosomal width 38.34 mm) resulting in very low
search record (0.3 ind. hr-1 per son-1). No individual was found in TC2.
Similarly, more individuals were found in TC3 (48 ind.) and ST (28 ind.)
respectively. In TC3, the search record was relatively higher (8.0 ind. hr-1
person-1) while the average body size was 47.52 mm (prosomal width ranged
34.76-88.93 mm). In ST, the search record was 4.7 ind. hr-1 person-1
while the average body size was 47.21 mm (prosomal width ranged 29.61-64.36
mm).
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 another survey of Jun. 2017, mating pairs
of Carcinoscorpius rotundicauda were
also found in TC2 (prosomal width: male 175.27 mm, female 143.51 mm) and TC3
(prosomal width: male 182.08 mm, female 145.63 mm) (Figure 3.2 of Appendix O). It indicated that breeding of horseshoe
crab could occur along the coast of Tung Chung Wan rather than ST only, as long
as suitable substratum was available. The 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.
3.6.20 In the previous
surveys (Jun. 2016, Jun. 2017) and present survey (Sep. 2017), there were
occasional records of large individuals of Carcinoscorpius
rotundicauda (prosomal width ranged 117.37- 178.67 mm, either single or in
pair) in ST (Fig. 3.3). 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 3.4 and
3.5 of Appendix O show the changes
of number of individuals, mean prosomal width and
search record of horseshoe crabs Carcinoscorpius
rotundicauda and Tachypleus
tridentatus respectively in every sampling zone throughout the monitoring
period.
3.6.24
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 Sep.. One possible
reason was that the serial cyclone hit decreased horseshoe crab activity
(totally 4 cyclone records between Jun. and Sep. 2017, to be discussed in
'Seagrass survey' section).
3.6.25
For
TC1, the search record was at low to medium level throughout the monitoring
period. The change of Carcinoscorpius
rotundicauda was relatively more variable than that of Tachypleus tridentatus. Relatively, the search record was very low
in TC2 (2 ind. in Sep. 2013; 1 ind. in Mar., Jun., Sep. 2014, Mar. and Jun.
2015; 4 ind. in Sep. 2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016, Mar., Jun.
and Sep. 2017).
3.6.26
About the body size, larger individuals of Carcinoscorpius rotundicauda were
usually found in ST and TC1 relative to those in TC3. For Tachypleus tridentatus, larger individuals were usually found in ST
followed by TC3 and TC1. Throughout the monitoring period, it was
obvious that TC3 and ST (western shore of Tung Chung Wan) was an important
nursery ground for horseshoe crab especially newly hatched individuals due to
larger area of suitable substratum (fine sand or soft mud) and less human
disturbance (far from urban district). Relatively, other sampling zones were
not a suitable nursery ground especially TC2. Possible factors were less area
of suitable substratum (especially TC1) and higher human disturbance (TC1 and
TC2: close to urban district and easily accessible). In TC2, large daily
salinity fluctuation was a possible factor either since it was flushed by two
rivers under tidal inundation. The individuals inhabiting TC1 and TC2 were
confined in small foraging area due to limited area of suitable substrata. Although
a mating pair of Carcinoscorpius
rotundicauda was found in TC2, the hatching rate and survival rate of newly
hatched individuals were believed very low.
Seasonal variation of horseshoe crab
population
3.6.27 Throughout the
monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures
3.3 and 3.4 of Appendix O). In Dec. 2012, 4 individuals of Carcinoscorpius rotundicauda and 12
individuals of Tachypleus tridentatus
were found only. In Dec. 2013, no individual of horseshoe crab was found. In
Dec. 2014, 2 individuals of Carcinoscorpius
rotundicauda and 8 individuals of Tachypleus
tridentatus were found only. In Dec. 2015, 2 individuals of Carcinoscorpius rotundicauda, 6
individuals of Tachypleus tridentatus
and one newly hatched, unidentified individual were found only. The horseshoe
crabs were inactive and burrowed in the sediments during cold weather (<15
ºC). Similar results of low search record in dry season were reported in a
previous territory-wide survey of horseshoe crab. For example, the search
records in Tung Chung Wan were 0.17 ind. hr-1 person-1 and 0.00 ind. hr-1
person-1 in wet season and dry season respectively (details see Li, 2008).
Relatively the serach records were much higher in Dec. 2016. There were totally
70 individuals of Carcinoscorpius
rotundicauda and 24 individuals of Tachypleus
tridentatus in TC3 and ST. Because the survey was arranged in early
December while the weather was warm with sunlight (~22 ºC during dawn according
to Hong Kong Observatory database, Chek Lap Kok station on 5 Dec). In contrast,
there was no search record in TC1 and TC2 because the survey was conducted in
mid December with colder and cloudy weather (~20 ºC during dawn on 19 Dec). The
horseshoe crab activity would decrease gradually with the colder climate.
3.6.28 From Sep. 2012 to
Dec. 2013, Carcinoscorpius rotundicauda
was a less common species relative to Tachypleus
tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This
species had ever been believed of very low density in ST hence the encounter
rate was very low. Since Mar. 2014, it was found in all sampling zones with
higher abundance in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and spawning of this species had
occurred about 3 years ago along the coastline of Tung Chun Wan. However, these
individuals were still small while their walking trails were inconspicuous.
Hence there was no search record in previous sampling months. Since Mar. 2014,
more individuals were recorded due to larger size and higher activity (i.e.
more conspicuous walking trail).
3.6.29
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.
3.6.30 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
3.6.31
Figure 3.6 of Appendix O shows the
changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus
tridentatus in TC3. As mentioned above, Carcinoscorpius rotundicauda
was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking.
In Mar 2014, the major size (50% of individual records between upper (top of
red box) and lower quartile (bottom of blue box)) ranged 40-60 mm while only
few individuals were found. From Mar. 2014 to Jun. 2017, the median prosomal
width (middle line of whole box) and major size (whole box) decreased after
Mar. of every year. It was due to more small individuals found. It indicated
new rounds of spawning. Also there were slight increasing trends of body size
from Jun. to Mar. of next year since 2015. It indicated a stable growth of
individuals. Focused on larger juveniles (upper whisker), the size range was
quite variable (prosomal width 60-90 mm) along the sampling months. Juveniles
reaching this size might gradually migrate to sub-tidal habitats.
3.6.32
For Tachypleus
tridentatus, the major size ranged 20-50 mm while the number of individuals
fluctuated from Sep. 2012 to Jun. 2014. Then a slight but consistent growing
trend was observed from Sep. 2014 to Jun. 2015. The prosomal width increased
from 25-35 mm to 35-65 mm. As mentioned, the large individuals might have
reached a suitable size for migrating from the nursery soft shore to subtidal
habitat. It accounted for the declined population in TC3. From Mar. to Sep.
2016, slight increasing trend of major size was noticed again. From Dec. 2016
to Jun. 2017, similar increasing trend of major size was noted with much higher
number of individuals. It reflected new round of spawning. In Sep. 2017
(present survey), 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).
Across the whole monitoring period, the larger juveniles (upper whisker)
reached 60-80 mm in prosomal width while it could reach 90 mm in present
survey. Juveniles reaching this size might gradually migrate to sub-tidal
habitats.
Box plot of horseshoe crab populations in ST
3.6.33
Figure 3.7 of Appendix O shows the
changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus
tridentatus in ST. As mentioned above, Carcinoscorpius rotundicauda
was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking.
From Mar. 2014 to Sep. 2017, the size of major population decreased and more
small individuals (i.e. lower whisker) were recorded after Jun. of every year.
It indicated new round of spawning. Also there were similar increasing trends
of body size from Sep. to Jun. of next year between 2014 and 2017. It indicated
a stable growth of individuals. Across the whole monitoring period, the larger
juveniles (i.e. upper whisker) usually ranged 60-80 mm in prosomal width except
one individual (prosomal width 107.04 mm) found in Mar. 2017. It reflected
juveniles reaching this size would gradually migrate to sub-tidal habitats.
3.6.34
For Tachypleus tridentatus, a consistent
growing trend was observed for the major population from Dec. 2012 to Dec. 2014
regardless of change of search record. The prosomal width increased from 15-30
mm to 60-70 mm. As mentioned, the large juveniles might have reached a suitable
size for migrating from the nursery soft shore to subtidal habitat. From Mar.
to Sep. 2015, the size of major population decreased slightly to a prosomal
width 40-60 mm. At the same time, the number of individuals decreased gradually.
It further indicated some of large juveniles might have migrated to sub-tidal
habitat, leaving the smaller individuals on shore. There was an overall growth
trend. In Dec. 2015, two big individuals (prosomal width 89.27 mm and 98.89 mm)
were recorded only while it could not represent the major population. In Mar.
2016, the number of individual was very few in ST that no boxplot could be
produced. In Jun. 2016, the prosomal width of major population ranged 50-70 mm.
But it dropped clearly to 30-40 mm in Sep. 2016 followed by an increase to
40-50 mm in Dec. 2016, 40-70 mm in Mar. 2017 and 50-60mm in Jun. 2017. Based on
overall higher number of small individuals from Jun. 2016 to Sep. 2017 (present
survey), it indicated new round of spawning. Throughout the monitoring period,
the larger juveniles ranged 60-80 mm in prosomal width. Juveniles reaching this
size would gradually migrate to sub-tidal habitats.
3.6.35
As a
summary for horseshoe crab populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014
to 2016 while the spawning time should be in spring. There were consistent,
increasing trends of population size in these two sampling zones. For Tachypleus tridentatus, small
individuals were rarely found in both zones from 2014 to 2015. It was believed
no occurrence of successful spawning. The existing individuals (that recorded
since 2012) grew to a mature size and migrated to sub-tidal habitat. Hence the
number of individuals decreased gradually. In 2016, new round of spawning was
recorded in ST while increasing number of individuals and body size was
noticed.
Impact of the HKLR project
3.6.36
It was the 20th 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
3.6.37
In the present survey, no seagrass bed was recorded
in Tung Chung Wan. Extensive area of mudflat, where used to
be covered by seagrass beds, re-exposed along TC3 and ST (Figure 3.8 of Appendix O). In the previous survey of Jun. 2017, two species
of seagrass Halophila ovalis and Zostera japonica were recorded in TC3
and ST (Figure 3.9 of Appendix O).
There was still extensive seagrass area (~17046.5 m2) of Halophila ovalis along the mudflat
between TC3 and ST at 0.5-2.0 m above C.D.. Another seagrass species Zostera japonica, which was much lower
in vegetation area (~105.4 m2), was co-existing with few patches of Halophila ovalis nearby the mangrove
strand. The disappearance of seagrass beds would be discussed in later
paragraphs.
3.6.38 According to the previous results, majority
of seagrass bed was confined in ST, the temporal change of both seagrass
species were investigated in details:
Temporal variation
of seagrass beds
3.6.39
Figure 3.10 of Appendix O shows the
changes of estimated total area of seagrass beds in ST along the sampling
months. For Zostera japonica, it was not recorded in the 1st
and 2nd surveys of monitoring programme. Seasonal recruitment of
few, small patches (total seagrass area: 10 m2) was found in Mar.
2013 that grew within the large patch of seagrass Halophila ovalis. Then
the patch size increased and merged gradually with the warmer climate from Mar.
to Jun. 2013 (15 m2). However the patch size decreased and remained
similar from Sep. 2013 (4 m2) to Mar. 2014 (3 m2). In
Jun. 2014, the patch size increased obviously again (41 m2) with
warmer climate followed by a decrease between Sep. 2014 (2 m2) and
Dec. 2014 (5 m2). From Mar. to Jun. 2015, the patch size increased
sharply again (90 m2). It might be due to the disappearance of the originally
dominant seagrass Halophila ovalis resulting in less competition for
substratum and nutrients. From Sep.2015 to Jun.2016, it was found coexisting
with seagrass Halophila ovalis with steady increasing patch size (from
44 m2 to 115 m2) and variable coverage. In Sep. 2016, the
patch size decreased again to (38 m2) followed by an increase to a
horizontal strand (105.4 m2) in Jun. 2017 (present survey). And it
was no longer co-existing with Halophila ovalis. Between Sep. 2014 and
Jun. 2017, an increasing trend was noticed from Sep. to Jun. of next year
followed by a rapid decline in Sep. of next year. It was possibly the causes of
heat stress, typhoon and stronger grazing pressure during wet season. In the
present survey, no seagrass patch of Zostera japonica was found. Such
disappearance matched the findings of previous monitoring period.
3.6.40 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 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.
3.6.41
In Dec. 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.10 of Appendix O shows the
difference of the original seagrass beds area nearby the mangrove vegetation at
high tidal level between Jun. 2014 and Dec. 2014. Such rapid loss would not be
seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m
above C.D.) were present and normal in December 2012 and 2013. According to
Fong (1998), similar incident had occurred in ST in the past. The original
seagrass area had declined significantly during the commencement of the
construction and reclamation works for the international airport at Chek Lap
Kok in 1992. The seagrass almost disappeared in 1995 and recovered gradually
after the completion of reclamation works. Moreover, incident of rapid loss of
seagrass area was also recorded in another intertidal mudflat in Lai Chi Wo in
1998 with unknown reason. Hence Halophila ovalis was regarded as a
short-lived and r-strategy seagrass
that could colonize areas in short period but disappears quickly under
unfavourable conditions (Fong, 1998).
Unfavourable
conditions to seagrass Halophila ovalis
3.6.42
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.
3.6.43 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).
3.6.44 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.
3.6.45 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
3.6.46
Figure
3.10 of Appendix O shows the
recolonization of seagrass bed area in ST from Dec. 2014 to Jun. 2017. From
Mar. to Jun. 2015, 2-3 small patches of Halophila
ovalis were newly found coinhabiting with another seagrass species Zostera japonica. But its total patch
area was still very low relative to the previous records. The recolonization
rate was low while cold weather and insufficient sunlight were possible factors
between Dec. 2014 and Mar. 2015. Moreover, it would need to compete with
seagrass Zostera japonica for
substratum and nutrient. Since Zostera
japonica had extended and had covered the original seagrass bed of Halophila ovalis at certain degree. From
Jun. 2015 to Mar. 2016, the total seagrass area of Halophila ovalis had increased rapidly from 6.8 m2
to 230.63 m2. It had recolonized its
original patch locations and covered Zostera
japonica. In Jun. 2016, the total seagrass area increased sharply to 4707.3
m2.
Similar to the previous records of Mar to Jun. 2014, the original patch area
increased further to a horizontally long strand. Another large seagrass beds
colonized the lower tidal zone (1.0-1.5 m above C.D.). In Sep. 2016, this patch
extended much and covered significant soft mud area of ST, resulting in sharp
increase of total area (24245 m2). It indicated the second extensive
colonization of this r-strategy seagrass. In Dec. 2016, this extensive seagrass
patch decreased in size and had separated into few, undistinguishable patches.
Moreover, the horizontal strand nearby the mangrove vegetation decreased in
size (Figure 3.10 of Appendix O).
The total seagrass bed decreased to 12550 m2. From Mar. to Jun. 2017,
the seagrass bed area remained generally stable (12438-17046.5 m2)
but the vegetation coverage fluctuated (20-50% in Mar. 2017 to 80-100% in Jun.
2017).
Re-disappearance of seagrass bed
3.6.47
In present survey, the whole seagrass bed of Halophila ovalis disappeared again along
the shore of TC3 and ST (Figure 3.10 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.
3.6.48
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).
3.6.49
According to the water quality monitoring
results (Jul. to Aug. 2017) of the two closest monitoring stations SR3 and I5
of the respective EM&A programme, the overall water quality was in normal
fluctuation. There was one exceedance of suspended solids (SS) at SR3 on 12
Jul. 2017. The SS concentration reached 24.7 mg/L during mid-ebb tide. It
exceeded the Action Level (≤23.5 mg/L) but was far below the Limit Level ((≤34.4 mg/L).
Since such exceedance was slight and temporary, its effect to seagrass bed
should be minimal.
3.6.50
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
recolonization would be a gradual process lasting for about 1.5 years.
Impact of the HKLR
project
Intertidal Soft Shore Communities
3.6.52
Table 3.2 and Figure 3.12 of Appendix O show the types of substratum along the
horizontal transect at every tidal level in all sampling zones. The relative
distribution of different substrata was estimated by categorizing the
substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random
quadrats along the horizontal transect. The distribution of substratum types
varied among tidal levels and sampling zones:
¡P In TC1, high
percentage of ¡¥Gravels and Boulders¡¦ (70%) was recorded at high tidal level
followed by ¡¥Sands¡¦ (30%). Even distribution of ¡¥Gravels and Boulders¡¦ (40%)
and ¡¥Sands¡¦ (40%) were recorded at mid tidal level. Relatively, the substratum
types of low tidal level were different while higher percentages of ¡¥Sands¡¦
(60%) and ¡¥Soft mud¡¦ (30%) were recorded.
¡P In TC2, the
substartum types were recorded evenly at high and mid tidal levels ('Soft mud'
40-50%, 'Gravels and Boulders' 30%, 'Sands' 20-30%,). At low tidal level, the
major substratum type was 'Soft mud' (80%) followed by 'Gravels and Boulders'
(20%).
¡P In TC3, high
percentages of ¡¥Sands¡¦ (70-90%) were recorded at high and mid tidal levels
followed by ¡¥Soft mud¡¦ (10-30%). At low tidal level, the major substratum type
was ¡¥Gravels and Boulders¡¦ (80%).
¡P In ST, ¡¥Gravels
and Boulders¡¦ was the main substratum (100%) at high and mid tidal levels. At
low tidal level, the substartum types were mainly ¡¥Soft mud¡¦ (60%) and 'Sands'
(40%).
3.6.53
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.
3.6.54
Table 3.3 of Appendix O lists
the total abundance, density and number of taxon of every phylum in this
survey. A total of 12099 individuals were recorded. Mollusca was clearly the
most abundant phylum (total abundance 11160 ind., density 372 ind. m-2,
relative abundance 92.2%). The second to fourth abundant phya were Arthropoda
(803 ind., 27 ind. m-2, 6.6%), Annelida (72 ind., 2 ind. m-2,
0.6%) and Sipuncula (37 ind., 1 ind. m-2, 0.3%) respectively.
Relatively other phyla were very low in abundances (density £1
ind. m-2, relative abundance £0.2%).
Moreover, the most diverse phylum was Mollusca (37 taxa) followed by Arthropoda
(14 taxa) and Annelida (6 taxa). There was 1-2 taxa recorded only for other
phyla. The taxonomic resolution and complete list of collected specimens are
shown in Annexes IV and V of Appendix O
respectively.
3.6.55
Table 3.4 of Appendix O
shows the number of individual, relative abundance and density of each phylum
in every sampling zone. The total abundance (1838-4026 ind.) varied among the
four sampling zones while the phyla distributions were similar. In general,
Mollusca was the most dominant phylum (no. of individuals: 1720-3638 ind.;
relative abundance 89.0-95.2%; density 229-485 ind. m-2). Other
phyla were much lower in number of individuals. Arthropoda was the second
abundant phylum (107-402 ind.; 3.7-10.0%; 14-54 ind. m-2). Annelida
was the third abundant phylum in TC2 and TC3 (26-33 ind.; 0.7-1.4%; 3-4 ind. m-2)
and fourth abundant in TC1 (12 ind.; 0.3%; 2 ind. m-2). Sipuncula
was relatively common in TC1 and TC3 (12-16 ind.; 0.3-0.4%; 2 ind. m-2).
Relatively other phyla were low in abundance in all sampling zones (≤ 0.2%).
Dominant
species in every sampling zone
3.6.56
Table 3.5 of Appendix O lists the abundant species (relative
abundance >10%) in every sampling zone. In the present survey, most of the
listed abundant species were of low to moderate densities (50-250 ind. m-2).
Few listed species of high or very high density (> 250 ind. m-2)
were regarded as dominant species. Other listed species of lower density (<
50 ind. m-2) were regared as common species.
3.6.57
In TC1,
the major substratum type was ¡¥Gravels and Boulders¡¦ at high tidal level. There
was dominant gastropod Batillaria
multiformis (337 ind. m-2, relative abundance 63%) followed by
gastropods Cerithidea djadjariensis
(84 ind. m-2, 16%) and Cerithidea
cingulata (62 ind. m-2, 11%) at low densities. At mid tidal
level (substratum types ¡¥Gravels and Boulders¡¦ and ¡¥Sands¡¦), there were few
abundant speices at low to moderate densities including gastropods Cerithidea djadjariensis (109 ind. m-2,
23%), Monodonta labio (81 ind. m-2,
17%), Batillaria multiformis (59 ind.
m-2, 13%), Cerithidea
cingulata (58 ind. m-2, 12%), as well as rock oyster Saccostrea cucullata (106 ind. m-2,
22%, attached on boulders). At low tidal level, few intertidal fauna were
recorded in the major substratum type ¡¥Sands¡¦. However abundant rock oyster Saccostrea cucullata (176 ind. m-2,
29%) and barnacle Balanus amphitrite (115
ind. m-2, 19 %) were attaching on the boulders.
3.6.58
In TC2,
gastropod Cerithidea djadjariensis
(172 ind. m-2, 40%) was abundant at moderate-high density at high
tidal level (major substratum types: ¡¥Soft mud¡¦ and 'Sands') followed by
gastropod Cerithidea cingulata (89
ind. m-2, 21%) and rock oyster Saccostrea
cucullata (56 ind. m-2, 13%, attached on boulders). At mid and
low tidal levels (major substratum types: ¡¥Soft mud¡¦ and 'Gravels and
Boulders'), gastropods Cerithidea
djadjariensis (32-83 ind. m-2, 15-25%), Batillaria zonalis
(42-63 ind. m-2, 19-20%) and rock oyster Saccostrea cucullata (61-62 ind. m-2, 18-29%) were found
common at low-moderate densities generally.
3.6.59 In TC3, the major substratum type was ¡¥Sands¡¦ at both high and mid
tidal levels. Gastropod Cerithidea djadjariensis was the dominant
species of moderate to high density (256-365 ind. m-2, 51-58%) followed by
another gastropod Cerithidea cingulata (129-163 ind. m-2, 26%). Besides
gastropod Batillaria multiformis (73 ind. m-2, 12%) was relatively
abundant at high tidal level. At low tidal level (major substratum: ¡¥Gravels
and Boulders¡¦), rock oyster Saccostrea cucullata (163 ind. m-2, 42%) and gastropod Monodonta
labio (126 ind. m-2, 32%) were abundant at
moderate densities.
3.6.60
In ST,
there was no clearly abundant species at all tidal levels. Gastropod Batillaria multiformis (56 ind. m-2,
24%), Monodonta labio (46 ind. m-2,
19%) and rock oyster Saccostrea cucullata
(35 ind. m-2, 15%) were common species at high tidal level (major
substratum: ¡¥Gravels and Boulders¡¦). At mid tidal level (major substratum:
¡¥Gravels and Boulders¡¦), rock oyster Saccostrea
cucullata (117 ind. m-2, 33%) was abundant at moderate density
followed by low-density gastropods Monodonta
labio (63 ind. m-2, 18 %), Lunella
coronata (46 ind. m-2, 13%) and Cerithidea djadjariensis (41 ind. m-2, 12%). At low
tidal level (major substratum types: ¡¥Sands¡¦ and ¡¥Soft mud¡¦), there were common
taxa only including rock oyster Saccostrea
cucullata (28 ind. m-2, 20%, attached on boulders), barnacle Balanus amphitrite (25 ind. m-2,
18%, attached on boulders), gastropods Cerithidea
djadjariensis (24 ind. m-2, 17%) and Batillaria zonalis (14 ind.
m-2, 10%).
3.6.61
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 Cerithidea djadjariensis (total number
of individuals: 2993 ind., relative abundance 24.7%), Cerithidea cingulata (1548 ind., 12.8%), Batillaria multiformis (1443 ind., 11.9%) and Batillaria zonalis
(509 ind., 4.2%) were the most commonly occurring species on sandy and soft mud
substrata. Rock oyster Saccostrea
cucullata (2101 ind., 17.4%), gastropods Monodonta labio (1116 ind., 9.2%), Lunella coronata (323 ind., 2.7%), barnacle Balanus amphitrite (438 ind., 3.6%) were commonly occurring species
inhabiting gravel and boulders substratum.
Biodiversity and abundance of soft shore
communities
3.6.62
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.
3.6.63
Among the sampling
zones, there was no obvious difference of mean species number, H' and J across all tidal levels. The mean species numbers of TC1, TC2 and
ST (9-10 spp. 0.25 m-2) were slightly higher than TC3 (7 spp. 0.25 m-2).
The mean densities of TC1 and TC3 (509-537 ind. m-2) were higher
than TC2 and ST (245-322 ind. m-2). Since TC3 was higher in mean
density and was highly dominant by few species, the mean H¡¦ (1.1) was relatively lower than other three sampling zones
(1.4-1.6). Overall the mean J was
similar among the four sampling zones (0.6-0.8).
3.6.64
Across the tidal
levels, there was no consistent difference of the mean species number, H' and J in all sampling zones. For the mean density, there were generally
decreasing trends in TC2, TC3 and ST from high to low tidal level.
3.6.65
Figures 3.13 to 3.16 of Appendix O show the temporal changes of mean species number,
mean density, H¡¦ and J at every tidal level and in every
sampling zone along the sampling months. In general, all the biological
parameters fluctuated seasonally throughout the monitoring period. Lower mean
species number and density were recorded in dry season (Dec.) but the mean H' and J fluctuated within a stable range.
3.6.66
Focusing on the
changes of mean density in ST, there were steady decreasing trends regardless
of tidal levels since the beginning of monitoring period. It might be an
unfavourable change that reflected environmental stresses. The mean densities
increased again from Dec. 2016 to Jun. 2017 reflecting a recovery process. But
it decreased again in Sep. 2017 (present survey) while the heat stress and
serial cyclone hit of this wet season were believed the causes. Because similar
decreases of density were noted in other sampling zones either.
Impact of the HKLR project
3.6.67
It was the 20th survey of the EM&A
programme during the construction period. Based on the results, impacts of the
HKLR project were not detected on intertidal soft shore community. In case of
other abnormal phenomena (e.g. rapid or consistent decline of fauna densities
and species number) are observed, it would be reported as soon as possible.
3.7
Solid and Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical
Waste Producer on 12 July 2012 for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental Licenses and Permits
3.8.1
The valid environmental licenses and permits
during the reporting period are summarized in Appendix L.
4
Environmental Complaint and Non-compliance
4.1.1 The detailed air quality, water
quality and dolphin exceedances are provided in Appendix M. Also, the summaries of the
environmental exceedances are presented as follows:
Air Quality
4.1.2
No Action Level and
Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS5 and
AMS6 during the reporting period.
Noise
4.1.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
4.1.4 No
Action Level and Limit Level exceedances for turbidity level and dissolved
oxygen level were recorded during the reporting period.
4.1.5 There
were 17 Action Level exceedances and 3 Limit Level exceedances of suspended
solids level during the reporting period. The exceedances of suspended solids
level recorded during reporting period were considered to be attributed to
other external factors such as sea condition, rather than the contract works.
The exceedances were considered as non-contract related.
Dolphin
4.1.6
There was one Limit Level exceedance of dolphin
monitoring for the quarterly monitoring data (between September 2017 - November
2017). According to the contractor¡¦s information, the marine activities
undertaken for HKLR03 during the quarter of September 2017 and November 2017
included seawall construction, box culvert construction,
road and drainage construction and road and drainage works.
4.1.7
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.
4.1.8 All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Marine Travel Route Plan, the travelling speed of
vessels must not exceed 5 knots when crossing the edge of the proposed marine
park. The Contractor will continue to provide training for skippers to ensure
that their working vessels travel from source to destination to minimize
impacts on Chinese White Dolphin and avoid anchoring at Marine Department¡¦s
designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
4.2
Summary of Environmental Complaint, Notification of
Summons and Successful Prosecution
4.2.1 There was one complaint received during the reporting period. The
summary of environmental complaint is presented in Table 4.1. The details of cumulative statistics of Environmental Complaints are
provided in Appendix N.
Table 4.1 A
Summary of Environmental Complaint for the Reporting Period
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaint
|
COM-2017-122
|
1823 Integrated Call Centre received a complaint lodged by
a member of the public on 30 September 2017. ET received complaint details on 3 October 2017.
|
Cleanliness problem at Tung Fai Road
|
4.2.2
For Environmental Complaint No. COM-2017-122,
complaint investigation was undertaken. Based on the investigation result,
there is no direct evidence showing that the complaint is related to Contract
No. HY/2011/03. Nevertheless, in order to enhance dust suppression measures,
the Contractor will increase the frequency of road cleaning by water bowser
from three times per day to four times per day, subject to regular review with
relevant stakeholders in the vicinity.
4.2.3
Statistics on notifications of summons and
successful prosecutions are summarized in Appendix M.
5
Comments,
Recommendations and Conclusion
5.1.1 According
to the environmental site inspections undertaken during the reporting period, the
following recommendations were provided:
¡P
The
Contractor was reminded to remove the waste at N1, N4, S9, S15, S16, S25, HAT,
HMA, Portion X, Ventilation Building, plant room at S15, and depressed
roundabout of N30.
¡P
The
Contractor was reminded to cover the cement bags with impervious sheeting at
Ventilation Building.
¡P
The
Contactor was reminded to provide drip tray for the chemical containers at N20,
S16, S25, HAT, A1 Bridge, Ventilation Building, and depressed roundabout of
N30.
¡P
The
Contactor was reminded to remove the stagnant water at N4, HMA, A1 Bridge, A2
Bridge, and depressed roundabout of N30.
¡P
The
Contactor was reminded to remove the concrete waste at S7 and S15.
¡P
The
Contractor was reminded to provide sufficient and regular water spraying to
minimize dust emission from vehicle movement on the access road of S25.
¡P
The
Contractor was reminded to cover the broken water barriers properly at S7.
¡P
The
Contractor was reminded to prevent water seepage by deploying sandbag barriers
at S7.
¡P
The
Contractor was reminded to replace the broken sandbag barriers were replaced
and close their gaps at S25.
¡P
The
Contractor was reminded to close the gaps of silt curtain at Portion X.
¡P
The
Contractor was reminded to maintain good housekeeping at HMA and depressed
roundabout of N30.
¡P
The
Contractor was reminded to store the chemical container in the designated
storage area of A1 Bridge.
¡P
The
Contractor was reminded to place the waste batteries in the chemical waste
storage area for collection by licensed collector at N4.
¡P
The
Contractor was reminded to place the contaminated soil in the chemical waste
area storage for collection by licensed collector at S16.
¡P
The
Contractor was reminded to cover the dump track at S15.
¡P
The
Contractor was reminded to adhere a NRMM label on to the air compressor at A1
Bridge.
¡P
The
Contractor was reminded to adhere a NRMM label on to the concrete pump at
depressed roundabout of N30.
¡P
The
Contractor was reminded to water/clean the site access regularly and provide
washing facilities for cleaning the vehicles before leaving the work area at
N20.
¡P
The
Contractor was reminded to water/clean the unpaved road at S25.
¡P
The
Contractor was reminded to remove the construction waste at S7, S25, and
depressed roundabout of N30.
¡P
The Contractor
was reminded to remove the unused blue hose at S11.
¡P
The
Contractor was reminded to remove the waste promptly and apply deodorant
control in the waste skip at S16.
5.2.1
The
impact monitoring programme for air quality, noise, water quality and dolphin
ensured that any deterioration in environmental condition was readily detected
and timely actions taken to rectify any non-compliance. Assessment and analysis
of monitoring results collected demonstrated the environmental impacts of the
contract. With implementation of the recommended environmental mitigation
measures, the contract¡¦s environmental impacts were considered environmentally
acceptable. The weekly environmental site inspections ensured that all the
environmental mitigation measures recommended were effectively implemented.
5.2.2 The recommended environmental mitigation
measures, as included in the EM&A programme, effectively minimize the
potential environmental impacts from the contract. Also, the EM&A programme
effectively monitored the environmental impacts from the construction
activities and ensure the proper implementation of mitigation measures. No
particular recommendation was advised for the improvement of the programme.
5.3.1
The construction phase and EM&A programme of
the Contract commenced on 17 October 2012. This is the twenty-first Quarterly
EM&A Report which summarizes the monitoring results and
audit findings of the EM&A programme during the reporting period from 1
September to 30 November 2017.
Air Quality
5.3.2 No Action Level and Limit Level exceedances of 1-hr
TSP and 24-hr TSP were recorded at AMS5 and AMS6 during the reporting period.
Noise
5.3.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
5.3.4 There were 17 Action Level exceedances and 3 Limit Level exceedances of
suspended solids level during the reporting period. No Action Level and Limit
Level exceedances for turbidity level and dissolved oxygen level were recorded
during the reporting period.
Dolphin
5.3.5 There was a Limit Level exceedance of
dolphin monitoring for the quarterly monitoring data between September 2017 -
November 2017.
5.3.6 During the present quarter of dolphin
monitoring, no adverse impact from the activities of this construction project
on Chinese White Dolphins was noticeable from general observations.
5.3.7 Although dolphins rarely occurred in the
area of HKLR03 construction in the past and during the baseline monitoring
period, it is apparent that dolphin usage has been dramatically reduced in NEL
since 2012, and many individuals have shifted away completely from the
important habitat around the Brothers Islands.
5.3.8
It is
critical to continuously monitor the dolphin usage in North Lantau region in
the upcoming quarters, to determine whether the dolphins are continuously
affected by the various construction activities in relation to the HZMB-related
works, and whether suitable mitigation measure can be applied to revert the
situation.
Mudflat -
Sedimentation Rate
5.3.9
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.
Mudflat - Ecology
5.3.10
The September 2017 survey was the twentieth
survey of the EM&A programme during the construction period. Based on the
results, impacts of the HKLR project could not be detected on horseshoe crabs,
seagrass and intertidal soft shore community.
Environmental Site Inspection and Audit
5.3.11
Environmental site inspection was carried out on
6, 13, 20 and 29 September 2017; 4, 11, 18, 25 and 31 October
2017; and 8, 15, 22 and 28 November 2017.
Recommendations on remedial actions were given to the Contractors for the
deficiencies identified during the site inspections.
5.3.12
There was one complaint received in relation to
the environmental impacts during the reporting period.
After investigation, there is no direct evidence showing that the complaint is
related to Contract No. HY/2011/03. Nevertheless, in order to enhance dust suppression
measures, the Contractor will increase the frequency of road cleaning by water
bowser from three times per day to four times per day, subject to regular
review with relevant stakeholders in the vicinity.
5.3.13
No notification of summons and prosecution was
received during the reporting period.