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.
19 (March 2017 to May 2017)
27
October 2017
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 nineteenth Quarterly EM&A report
for the Contract which summarizes the monitoring results and audit findings of
the EM&A programme during the reporting period from 1 March 2017 to 31 May 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
|
March 2017
|
April
2017
|
May 2017
|
Air
Quality
|
1-hr
TSP
|
1, 7, 13, 17, 23 and 29
|
3, 7, 13, 19, 25 and 28
|
4, 10, 16, 22 and 26
|
24-hr
TSP
|
6, 10, 16, 22 and 28
|
1, 6, 12, 18, 24 and 27
|
2, 8, 13, 19, 25 and 31
|
Noise
|
1, 7, 13, 23 and 29
|
3, 13, 19 and 25
|
4, 10, 16 and 22
|
Water
Quality
|
1, 3, 6, 8, 10, 13, 15, 17, 20, 22, 24, 27,
29 and 31
|
3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26 and
28
|
1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 26, 29
and 31
|
Chinese
White Dolphin
|
2, 7, 16 and 28
|
12, 20, 24 and 26
|
18, 22, 24 and 26
|
Mudflat
Monitoring (Ecology)
|
3, 4, 10 and 14
|
--
|
--
|
Mudflat
Monitoring (Sedimentation rate)
|
28
|
--
|
--
|
Site Inspection
|
8, 15, 22 and 31
|
5,
12, 19 and 28
|
4,
10, 17 and 26
|
Due to boat
availability, the dolphin monitoring schedule was rescheduled from 6 March 2017
to 7 March 2017. Due to weather condition, the dolphin monitoring schedule was
rescheduled from 15 March 2017 to 16 March 2017. Due to resource arrangement,
the dolphin monitoring schedule was rescheduled from 20 March 2017 to 28 March
2017. Due to weather condition, the dolphin monitoring schedule was rescheduled
from 15 May 2017 to 24 May 2017. Due to boat availability, the dolphin
monitoring schedule was rescheduled from 23 May 2017 to 22 May 2017.
The water
quality monitoring on 31 March 2017 during mid-ebb tide was cancelled for
safety reason as the thunderstorm signal was hoisted by Hong Kong Observatory
and lightning was recorded at the water quality monitoring stations. The water quality monitoring on 15 May 2017 during mid-flood tide and
the water quality monitoring on 24 May 2017 during mid-ebb tide and mid-flood
tide were cancelled for safety reason as the thunderstorm signal was hoisted by
the Hong Kong Observatory and lightning was recorded at the water quality monitoring
locations. No substitute monitoring was conducted due to boat availability.
Due to the
Action/Limit level exceedances of 1-hr TSP were recorded at AMS5 and AMS6 on 10
May 2017, an additional 1-hr TSP monitoring was conducted on 11 May 2017 at AMS5
and AMS6 respectively.
Due to enough
manpower for surveys at the same time, the mudflat monitoring was rescheduled
from 11 March 2017 to 4 March 2017 and from 13 March 2017 to 4 March 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
|
2
|
3
|
24-hr TSP
|
0
|
0
|
Noise
|
Leq
(30 min)
|
0
|
0
|
Water Quality
|
Suspended
solids level (SS)
|
3
|
3
|
Turbidity
level
|
2
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin Monitoring
|
Quarterly
Analysis (Mar 2017 to May 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 were five complaints 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-2017-108
|
23 February 2017
and 2 March 2017
|
Cleanliness problem at East Coast Road
|
COM-2017-112
|
27 March 2017
|
Noise and Water Quality
|
COM-2017-113
|
20 April 2017
|
Water quality problem at Portion X
|
COM-2017-095(3)
|
27 May 2017
|
Noise nuisance near Dragonair / CNAC (Group)
Building (HKIA)
|
Notifications of Summons and Prosecutions
There were no notifications of summons or
prosecutions received during this reporting period.
Reporting Changes
This report has been developed in compliance
with the reporting requirements for the quarterly summary EM&A reports as
required by the Updated EM&A Manual for HKLR (Version 1.0).
The proposal for the change of Action Level and
Limit Level for suspended solid and turbidity was approved by EPD on 25 March
2013.
The revised Event and Action Plan for dolphin monitoring was approved by EPD on 6 May 2013.
The original monitoring station at IS(Mf)9
(Coordinate- East:813273, North 818850) was observed inside the perimeter silt
curtain of Contract HY/2010/02 on 1 July 2013, as such the original impact
water quality monitoring location at IS(Mf)9 was temporarily shifted outside
the silt curtain. As advised by the
Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted
to facilitate safe anchorage zone of construction barges/vessels until end of
2013 subject to construction progress.
Therefore, water quality monitoring station IS(Mf)9 was shifted to
813226E and 818708N since 1 July 2013.
According to the water quality monitoring team¡¦s observation on 24 March
2014, the original monitoring location of IS(Mf)9 was no longer enclosed by the
perimeter silt curtain of Contract HY/2010/02. Thus, the impact water quality
monitoring works at the original monitoring location of IS(Mf)9 has been
resumed since 24 March 2014.
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.
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 nineteenth Quarterly
Environmental Monitoring and Audit (EM&A) report for the Contract which
summarizes the monitoring results and audit findings of the EM&A programme
during the reporting period from 1 March 2017 to 31 May 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
|
Construction of tunnel box structure at
Scenic Hill Tunnel (Cut & Cover Tunnel)
|
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
|
Excavation for diversion of culvert PR14
|
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 excavation/ box jacking
underneath Airport Road and Airport Express Line
|
Airport Road and Airport Express Line
|
Construction of Tunnel box structure at
Package T1.12.1
|
Near Kwo Lo Wan Road
|
Construction of Tunnel box structure
|
Shaft 3 Extension South & 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 works
for Highway Operation and Maintenance Area Building
|
Portion X
|
Superstructure works for Scenic Hill
Tunnel West Portal Ventilation Building
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)
|
NMS5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡P Depth
¡P Temperature
¡P Salinity
¡P Dissolved Oxygen
(DO)
¡P Suspended Solids
(SS)
¡P DO Saturation
¡P Turbidity
¡P pH
|
¡P Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,
¡P Control/Far Field
Stations:
CS2 & CS(Mf)5,
¡P Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A & SR10B
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 1.75 hour of the predicted time)
|
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth be less than 3
m, only the mid-depth station will be monitored).
|
Dolphin
|
Line-transect Methods
|
Northeast Lantau survey
area and Northwest Lantau survey area
|
Twice
per month
|
--
|
Mudflat
|
Horseshoe crabs, seagrass beds, intertidal soft shore communities,
sedimentation rates and water quality
|
San Tau and Tung Chung Bay
|
Once every 3 months
|
--
|
2.2.1
Table 2.2 presents
the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.
Table 2.2 Action
and Limit Levels for 1-hour TSP, 24-hour TSP and Noise
Environmental Monitoring
|
Parameters
|
Monitoring Station
|
Action Level
|
Limit Level
|
Air
Quality
|
1-hr TSP
|
AMS
5
|
352 µg/m3
|
500 µg/m3
|
AMS
6
|
360 µg/m3
|
24-hr TSP
|
AMS
5
|
164 µg/m3
|
260 µg/m3
|
AMS
6
|
173 µg/m3
|
Noise
|
Leq
(30 min)
|
NMS 5
|
When
one documented complaint is received
|
75
dB(A)
|
2.2.2
The Action and Limit
Levels for water quality monitoring are given as in Table 2.3.
Table 2.3 Action
and Limit Levels for Water Quality
Parameter
(unit)
|
Water Depth
|
Action
Level
|
Limit Level
|
Dissolved Oxygen (mg/L)
|
Surface and Middle
|
5.0
|
4.2 except 5 for Fish
Culture Zone
|
Bottom
|
4.7
|
3.6
|
Turbidity (NTU)
|
Depth average
|
27.5 or 120% of upstream
control station¡¦s turbidity at the same tide of the same day;
The action level has been
amended to ¡§27.5 and 120% of upstream control station¡¦s turbidity at the same
tide of the same day¡¨ since 25 March 2013.
|
47.0 or 130% of turbidity
at the upstream control station at the same tide of same day;
The limit level has been
amended to ¡§47.0 and 130% of turbidity at the upstream control station at the
same tide of same day¡¨ since 25 March 2013.
|
Suspended Solid (SS)
(mg/L)
|
Depth average
|
23.5 or 120% of upstream
control station¡¦s SS at the same tide of the same day;
The action level has been
amended to ¡§23.5 and 120% of upstream control station¡¦s SS at the same tide of
the same day¡¨ since 25 March 2013.
|
34.4 or 130% of SS at the
upstream control station at the same tide of same day and 10mg/L for Water
Services Department Seawater Intakes;
The limit level has been
amended to ¡§34.4 and 130% of SS at the upstream control station at the same
tide of same day and 10mg/L for Water Services Department Seawater Intakes¡¨
since 25 March 2013
|
Notes:
(1) Depth-averaged is
calculated by taking the arithmetic means of reading of all three depths.
(2) For DO, non-compliance
of the water quality limit occurs when monitoring result is lower that the
limit.
(3) For SS & turbidity
non-compliance of the water quality limits occur when monitoring result is
higher than the limits.
(4) The change to the
Action and limit Levels for Water Quality Monitoring for the EM&A works was
approved by EPD on 25 March 2013. Therefore, the amended Action and Limit
Levels are applied for the water monitoring results obtained on and after 25
March 2013.
2.2.3
The Action and Limit
Levels for dolphin monitoring are shown in Tables
2.4 and 2.5.
Table 2.4 Action
and Limit Level for Dolphin Impact Monitoring
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
Limit Level
|
STG < 40% of baseline
&
ANI < 40% of baseline
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
Table 2.5 Derived
Value of Action Level (AL) and Limit Level (LL)
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 4.2 & ANI < 15.5
|
STG < 6.9 & ANI
< 31.3
|
Limit Level
|
(STG < 2.4 & ANI
< 8.9) and (STG < 3.9 & ANI < 17.9)
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
2.3.1
The Event Actions Plans for air quality, noise,
water quality and dolphin monitoring are annexed in Appendix D.
2.4.1 Environmental
mitigation measures for the contract were recommended in the approved EIA
Report. Appendix E lists the recommended
mitigation measures and the implementation status.
3
Environmental
Monitoring and Audit
3.1
Implementation of
Environmental Measures
3.1.1
In response to the site audit findings, the
Contractor have rectified all observations identified in environmental site
inspections undertaken during the reporting period. Details of site audit
findings and the corrective actions during the reporting period are presented
in Appendix F.
3.1.2
A summary of the Implementation Schedule of
Environmental Mitigation Measures (EMIS) is presented in Appendix E.
3.1.3 Regular
marine travel route for marine vessels were implemented properly in accordance
to the submitted plan and relevant records were kept properly.
3.1.4 Dolphin
Watching Plan was implemented during the reporting period.
No dolphins inside the silt curtain were observed. The relevant records were
kept properly.
3.2.1 The
monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2
respectively. Detailed impact air quality monitoring results and relevant graphical
plots are presented in Appendix G.
Table 3.1 Summary
of 1-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
March 2017
|
AMS5
|
87
|
35 ¡V 249
|
352
|
500
|
AMS6
|
109
|
59 ¡V 225
|
360
|
April 2017
|
AMS5
|
54
|
16 ¡V 106
|
352
|
AMS6
|
72
|
32 ¡V 126
|
360
|
May 2017
|
AMS5
|
140
|
9 ¡V 719
|
352
|
AMS6
|
124
|
7 ¡V 569
|
360
|
Table 3.2 Summary
of 24-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
March 2017
|
AMS5
|
84
|
50 ¡V 143
|
164
|
260
|
AMS6
|
88
|
68 ¡V 108
|
173
|
April 2017
|
AMS5
|
51
|
37 ¡V 66
|
164
|
AMS6
|
65
|
47 ¡V 79
|
173
|
May 2017
|
AMS5
|
57
|
32 ¡V 74
|
164
|
AMS6
|
75
|
42 ¡V 110
|
173
|
3.2.2
No Action Level
exceedances of 1-hr TSP were recorded at AMS5 and no Action and Limit Level
exceedances of 24-hr TSP were recorded at AMS5 and AMS6 during the reporting
period.
3.2.3
On 10 May 2017, two
Limit Level exceedances of 1-hr TSP level were recorded at AMS5 while two
Action Level and one Limit Level exceedances of 1-hr TSP level were recorded at
AMS6 during the reporting period. The Air Quality Health Index recorded by EPD
at the Tung Chung station during the sampling period (8:00 to 16:00) ranged
from 3 (low) to 10+ (serious). The general weather conditions in Tung Chung
were sunny and haze with a low visibility during the sampling periods. The haze
weather could cause higher readings of the portable dust meter. It was noted
that the Contractor had implemented dust control measures throughout the construction
phase. No fugitive dust emission was observed by ET on 10 May 2017 at
construction site near monitoring stations AMS5 and AMS6. It was considered
that the exceedances were not related to the construction activities of the
Contract and were caused by the weather condition. In this case, no immediate
actions are required. However, the Contractor is reminded to continuously
implement the dust control measures throughout the construction phase. Record
of notification of environmental quality limit exceedances are provided in Appendix M.
3.3
Noise Monitoring Results
3.3.1
The monitoring results for construction noise
are summarized in Table 3.3 and the
monitoring results and relevant graphical plots for this reporting
period are provided in Appendix H.
Table 3.3 Summary of Construction Noise
Monitoring Results Obtained During the Reporting Period
Reporting period
|
Monitoring Station
|
Average Leq (30 mins),
dB(A)*
|
Range of Leq (30
mins), dB(A)*
|
Action Level
|
Limit Level Leq (30
mins), dB(A)
|
March 2017
|
NMS5
|
59
|
55 ¡V 62
|
When one documented complaint is received
|
75
|
April 2017
|
64
|
59 ¡V 73
|
May 2017
|
63
|
60 ¡V 65
|
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.
3.4.2 An Action Level exceedance of suspended solid was recorded at station
SR5 during mid-flood tide on 3 March 2017. Removal of surcharge and box culvert
construction at Zones 1 and 2, drilling of pipe pile at Zone 1, seawall
construction at Zones 2 and 3A, and transportation of fill material at Zone 3A
were carried out within the properly deployed silt curtain as recommended in
the EIA Report. There was no marine transportation at Zones 1, 2, and 3A. There
were no specific activities recorded during the monitoring period that would
cause any significant impacts on the monitoring results. No marine works was
conducted near monitoring station SR5 which is located outside the site
boundary of HKLR03 Contract. Also,
there was no muddy plume observed at station SR5 during sampling exercise. No
leakage of turbid water or any abnormity or malpractice for all contract works
was observed during the sampling exercise.
3.4.3 Two Action Level exceedances of turbidity level were recorded at
stations SR4 and IS8 on 24 March 2017. Also, an Action Level exceedance of
suspended solid was recorded at station IS8 during mid-ebb tide and Three Limit
Level exceedances of suspended solid were record at station SR4 during mid-ebb
tide and at stations IS8 and SR4 during mid-flood tide on 24 March 2017.
Removal of surcharge and box culvert construction at Zones 1 and 2, seawall
construction at Zones 2 and 3A and transportation of fill material at Zone 3A
were carried out within the properly deployed silt curtain as recommended in
the EIA Report. Yellow-brown colour of water was observed at stations IS8 and
SR4 during sampling exercise. However, there was no marine transportation at
Zones 1, 2, and 3A and no marine works was conducted near monitoring stations
SR4 and IS8 which are located outside the site boundary of HKLR03 Contract.
There were no water quality exceedances at monitoring stations IS7 and IS(Mf)6
which are located closer to active work of the HKLR03 Contract than monitoring
stations IS8 and SR4. No leakage of turbid water or any abnormity or
malpractice for the contract works was observed during the sampling exercise.
3.4.4 On 27 March 2017, an Action Level exceedance of suspended solid was
recorded at station IS8 during mid-ebb tide. Removal of surcharge and box
culvert construction at Zones 1 and 2, seawall construction at Zones 2 and 3A
and transportation of fill material at Zone 3A were carried out within the
properly deployed silt curtain as recommended in the EIA Report. There was no
marine transportation at Zones 1, 2, and 3A and no marine work was conducted
near monitoring station IS8 which is located outside the site boundary of
HKLR03 Contract. There were no
specific activities recorded during the monitoring period that would cause any
significant impacts on the monitoring results. Also, there was no muddy plume
observed at station IS8 during sampling exercise. No leakage of turbid water or
any abnormity or malpractice for the contract works was observed during the
sampling exercise.
3.4.5 Record of ¡§Notification of Environmental Quality Limit Exceedances¡¨ is
provided in Appendix M.
3.4.6
Water quality impact sources during the water
quality monitoring were the construction activities of the Contract, nearby
construction activities by other parties and nearby operating vessels by other
parties.
Data
Analysis
3.5.1 Distribution Analysis ¡V The
line-transect survey data was integrated with the Geographic Information
System (GIS) in order to visualize and interpret different spatial and temporal
patterns of dolphin distribution using sighting positions. Location data of dolphin groups were
plotted on map layers of Hong Kong using a
desktop GIS (ArcView© 3.1) to examine their distribution patterns in
details. The dataset was also
stratified into different subsets to examine distribution patterns of dolphin
groups with different categories of group sizes, young calves and activities.
3.5.2
Encounter rate analysis ¡V Encounter rates of
Chinese white dolphins (number of on-effort sightings per 100 km of survey
effort, and total number of dolphins sighted on-effort per 100 km of survey effort)
were calculated in NEL and NWL survey areas in relation to the amount of survey
effort conducted during each month of monitoring survey. Dolphin encounter rates were calculated
in two ways for comparisons with the HZMB baseline monitoring results as well
as to AFCD long-term marine mammal monitoring results.
3.5.3
Firstly, for the comparison with the HZMB
baseline monitoring results, the encounter rates were calculated using primary
survey effort alone, and only data collected under Beaufort 3 or below
condition would be used for encounter rate analysis. The average encounter rate of sightings
(STG) and average encounter rate of dolphins (ANI) were deduced based on the
encounter rates from six events during the present quarter (i.e. six sets of
line-transect surveys in North Lantau), which was also compared with the one
deduced from the six events during the baseline period (i.e. six sets of
line-transect surveys in North Lantau).
3.5.4
Secondly, the encounter rates were calculated
using both primary and secondary survey effort collected under Beaufort 3 or
below condition as in AFCD long-term monitoring study. The encounter rate of sightings and
dolphins were deduced by dividing the total number of on-effort sightings (STG)
and total number of dolphins (ANI) by the amount of survey effort for the
present quarterly period.
3.5.5
Quantitative grid analysis on habitat use ¡V To
conduct quantitative grid analysis of habitat use, positions of on-effort
sightings of Chinese White Dolphins collected during the quarterly impact phase
monitoring period were plotted onto 1-km2 grids among NWL and NEL
survey areas on GIS. Sighting
densities (number of on-effort sightings per km2) and dolphin
densities (total number of dolphins from on-effort sightings per km2)
were then calculated for each 1 km by 1 km grid with the aid of GIS. Sighting density grids and dolphin
density grids were then further normalized with the amount of survey effort
conducted within each grid. The
total amount of survey effort spent on each grid was calculated by examining
the survey coverage on each line-transect survey to determine how many times
the grid was surveyed during the study period. For example, when the survey boat
traversed through a specific grid 50 times, 50 units of survey effort were
counted for that grid. With the
amount of survey effort calculated for each grid, the sighting density and
dolphin density of each grid were then normalized (i.e. divided by the unit of
survey effort).
3.5.6 The
newly-derived unit for sighting density was termed SPSE, representing the
number of on-effort sightings per 100 units of survey effort. In addition, the derived unit for actual
dolphin density was termed DPSE, representing the number of dolphins per 100
units of survey effort. Among the
1-km2 grids that were partially covered by land, the percentage of
sea area was calculated using GIS tools, and their SPSE and DPSE values were
adjusted accordingly. The following
formulae were used to estimate SPSE and DPSE in each 1-km2 grid
within the study area:
SPSE = ((S / E) x 100) /
SA%
DPSE = ((D / E) x 100) /
SA%
where S =
total number of on-effort sightings
D = total number of
dolphins from on-effort sightings
E = total number of units
of survey effort
SA% = percentage of sea
area
3.5.7 Behavioural
analysis ¡V When dolphins were sighted during vessel surveys, their behaviour
was observed. Different activities
were categorized (i.e. feeding, milling/resting, traveling, socializing) and
recorded on sighting datasheets.
This data was then input into a separate database with sighting
information, which can be used to determine the distribution of behavioural
data with a desktop GIS.
Distribution of sightings of dolphins engaged in different activities
and behaviours would then be plotted on GIS and carefully examined to identify
important areas for different activities of the dolphins.
3.5.8 Ranging
pattern analysis ¡V Location data of individual dolphins that occurred during
the 3-month baseline monitoring period were obtained from the dolphin sighting
database and photo-identification catalogue. To deduce home ranges for individual
dolphins using the fixed kernel methods, the program Animal Movement Analyst
Extension, was loaded as an extension with ArcView© 3.1 along with
another extension Spatial Analyst 2.0.
Using the fixed kernel method, the program calculated kernel density
estimates based on all sighting positions, and provided an active interface to
display kernel density plots. The
kernel estimator then calculated and displayed the overall ranging area at 95%
UD level.
Summary of Survey
Effort and Dolphin Sightings
3.5.9
During the period
of March to May 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 830.17 km of survey effort was collected, with 93.4% 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, 333.83 km and
496.34 km of survey effort were conducted in NEL and NWL survey areas
respectively.
3.5.11
The total survey
effort conducted on primary lines was 583.29 km, while the effort on secondary
lines was 246.88 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 March to May 2017, only four groups of 24 Chinese
White Dolphins were sighted. A
summary table of the dolphin sightings is shown in Annex II of Appendix J.
3.5.13
For the present quarterly period, all four
dolphin sightings were made during on-effort search, while three of the four
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
3.5.14
Distribution
of dolphin sightings made during monitoring surveys in March to May 2017 is
shown in Figure 1 of Appendix J.
Two of the dolphin sightings were made at the northwest corner of Lung
Kwu Chau, while the other two sightings were located near Black Point and to
the east of Sha Chau respectively (Figure
1 of Appendix J). On the other
hand, the dolphins were completely absent from the central and eastern portions
of North Lantau waters as in previous quarters (Figure 1 of Appendix J).
3.5.15
All
dolphin sightings were located far away from the HKBCF and HKLR03 reclamation
sites as well as along the alignments of HKLR09 and Tuen Mun-Chek Lap Kok Link
(TMCLKL) (Figure 1 of Appendix J).
3.5.16
Sighting distribution of dolphins during the
present impact phase monitoring period (March to May 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 16 quarters
of HKLR03 monitoring, which has resulted in zero to extremely low dolphin
encounter rates in this area.
3.5.17
In NWL survey area, dolphin occurrence was also
significantly different between the baseline and impact phase periods. During the present impact monitoring
period, only a handful of dolphin sightings were made in this survey area,
which was in stark contrast with their frequent occurrences throughout the area
during the baseline period (Figure 1 of
Appendix J).
3.5.18
Another
comparison in dolphin distribution was made between the five quarterly periods
of spring months in 2013-17 (Figure 2 of
Appendix J). Among the five
spring periods, dolphins were regularly sighted in NWL waters in 2013 and 2014,
but their usage there was dramatically reduced in the three subsequent spring
periods, with the only occurrences mostly concentrated within and around the
Sha Chau and Lung Kwu Chau Marine Park (Figure
2 of Appendix J).
Encounter Rate
3.5.19
During the present three-month study period, the
encounter rates of Chinese White Dolphins deduced from the survey effort and
on-effort sighting data from the primary transect lines under favourable
conditions (Beaufort 3 or below) for each set of the surveys in NEL and NWL are
shown in Table 3.4. The average encounter rates deduced from
the six sets of surveys were also compared with the ones deduced from the
baseline monitoring period (September ¡V November 2011) (Table 3.5).
3.5.20 To facilitate the comparison with
the AFCD long-term monitoring results, the encounter rates were also calculated
for the present quarter using both primary and secondary survey effort. The encounter rates of sightings (STG)
and dolphins (ANI) in NWL were 0.87 sightings and 5.23 dolphins per 100 km of
survey effort respectively, while the encounter rates of sightings (STG) and
dolphins (ANI) in NEL were both nil for this quarter.
Table
3.4 Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) During Reporting Period
(March to May 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 (2 & 7 Mar 2017)
|
0.00
|
0.00
|
Set 2 (16 & 28 Mar 2017)
|
0.00
|
0.00
|
Set 3 (12 & 20 Apr
2017)
|
0.00
|
0.00
|
Set 4 (24 & 26 Apr 2017)
|
0.00
|
0.00
|
Set 5 (18
& 22 May
2017)
|
0.00
|
0.00
|
Set 6 (24 & 26 May 2017)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (2 & 7 Mar 2017)
|
0.00
|
0.00
|
Set 2 (16 & 28 Mar 2017)
|
2.03
|
24.37
|
Set 3 (12 & 20 Apr
2017)
|
1.71
|
3.41
|
Set 4 (24 & 26 Apr 2017)
|
0.00
|
0.00
|
Set 5 (18
& 22 May
2017)
|
1.85
|
3.70
|
Set 6 (24 & 26 May 2017)
|
0.00
|
0.00
|
Table
3.5 Comparison of average dolphin encounter rates from impact monitoring
period (March to May 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
|
0.93 ¡Ó
1.03
|
9.85 ¡Ó 5.85
|
5.25 ¡Ó 9.53
|
44.66 ¡Ó 29.85
|
Notes:
1) The encounter rates deduced from the baseline monitoring period have been
recalculated based only on the survey effort and on-effort sighting data made
along the primary transect lines under favourable conditions.
2) ¡Ó denotes the standard deviation of the average
encounter rates.
3.5.21
In NEL,
the average dolphin encounter rates (both STG and ANI) in the present
three-month impact monitoring period were both zero with no on-effort sighting
being made, and such extremely low occurrence of dolphins in NEL have been
consistently recorded in the past 16 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*
|
Notes:
1) The encounter rates
deduced from the baseline monitoring period have been recalculated based only
on survey effort and on-effort sighting data made along the primary transect
lines under favourable conditions.
2) ¡Ó denotes the standard
deviation of the average encounter rates.
3) The encounter rates in
spring months were in blue and marked with asterisk.
3.5.22
On the
other hand, the average dolphin encounter rates (STG and ANI) in NWL during the
present impact phase monitoring period (reductions of 90.5% and 88.2%
respectively) were only tiny fractions of the ones recorded during the
three-month baseline period, indicating a dramatic decline in dolphin usage of
this survey area as well during the present impact phase period (Table 3.7).
3.5.23
During the same spring quarters, dolphin
encounter rates in NWL during spring 2017 was similar to the previous two
spring periods, but was much lower than the ones in the spring periods of 2013
and 2014 (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*
|
Notes:
1) The encounter rates deduced from the
baseline monitoring period have been recalculated based only on survey effort
and on-effort sighting data made along the primary transect lines under
favourable conditions.
2) ¡Ó denotes the standard deviation of the average encounter rates.
3) The
encounter rates in spring months were in blue and marked with asterisk.
3.5.24 As
recently discussed in Hung (2016), 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.
3.5.25
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).
3.5.26
For the
comparison between the baseline period and the present quarter (18th
quarter of the impact phase being assessed), the p-values for the differences
in average dolphin encounter rates of STG and ANI were 0.0019 and 0.0186
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.
3.5.27
For the comparison between the baseline period
and the cumulative quarters in impact phase (i.e. the first 18 quarters of the
impact phase being assessed), the p-values for the differences in average
dolphin encounter rates of STG and ANI were 0.000001 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).
3.5.28
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.
This 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 2016), and apparently there was no sign of
recovery of dolphin usage even though most of the 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 twelve individuals per group
in North Lantau region during March to May 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 (Mar 2017 ¡V May 2017)
and Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average
Dolphin Group Size
|
Reporting
Period
|
Baseline
Monitoring Period
|
Overall
|
6.00
¡Ó 4.90 (n = 4)
|
3.72
¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18
¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
6.00 ¡Ó 4.90 (n = 4)
|
3.92
¡Ó 3.40 (n = 49)
|
Note:
1) ¡Ó denotes the standard deviation of the average
group size.
3.5.30 The
average dolphin group size in NWL waters during March to May 2017 was much
higher than the one recorded during the three-month baseline period, but it
could be partly related to the very small sample size of four groups when
compared to the 66 groups sighted during the baseline period (Table 3.8). Two of these dolphin groups were
composed of two individuals respectively, while the other two groups were large
with eight and twelve individuals respectively (Annex II of Appendix J).
3.5.31
Distribution
of the two large dolphin groups (i.e. 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 group of eight individuals was
sighted at the northwest corner of Lung Kwu Chau, whereas the group of 12
individuals was sighted to the east of Sha Chau (Figure 3 of Appendix J).
Such distribution pattern was very different from the baseline period,
when the larger dolphin groups were frequently sighted and evenly distributed
in NWL waters, with a few also sighted in NEL waters (Figure 3 of Appendix J).
Habitat Use
3.5.32
From
March to May 2017, the two grids with high dolphin densities were located at
Lung Kwu Chau and Sha Chau, while the other two grids recorded low dolphin
densities (Figures 4a and 4b of Appendix
J). All grids near HKLR03/HKBCF
reclamation sites as well as HKLR09/TMCLKL alignments did not record any
presence of dolphins at all during on-effort search in the present quarterly
period (Figures 4a and 4b of Appendix J).
3.5.33
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.
3.5.34
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).
3.5.35
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 two grids with high dolphin densities were located at Lung Kwu
Chau and Sha Chau during the present impact phase period (Figure 5 of Appendix J).
Mother-calf Pairs
3.5.36
During the present quarterly period, no young calf
was sighted at all among the four groups of dolphins.
Activities and Associations with Fishing Boats
3.5.37 Only one of the four groups was engaged in feeding
activities, while none of them was engaged in socializing, traveling or
milling/resting activity during the three-month study period.
3.5.38
The percentage of
sightings associated with feeding activity (25.0%) was much higher than the one
recorded during the baseline period (11.6%). However, it should be noted the sample
size on total numbers of dolphin sightings during the present quarter (four
dolphin groups) was much lower than the baseline period (66 dolphin groups).
3.5.39
Distribution
of dolphins engaged in various activities during the present impact phase
period and the baseline period is shown in Figure
6 of Appendix
J. The only dolphin group engaged in
feeding activity was sighted to the west of Sha Chau during the present
quarterly period, which was very different from the baseline period when
various dolphin activities occurred throughout the North Lantau region (Figure 6 of Appendix J).
3.5.40
Notably, one of the
four dolphin groups was found to be associated with an operating purse-seiner
during the present impact phase period.
Summary
Photo-identification works
3.5.41
From March to May
2017, over 1,500 digital photographs of Chinese White Dolphins were taken
during the impact phase monitoring surveys for the photo-identification work.
3.5.42
In
total, 15 individuals sighted 19 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. Two individuals (NL123 and
NL286) were re-sighted twice, while one individual (NL202) was re-sighted
thrice during the three-month period (Annex
III of Appendix J).
3.5.43
Notably,
two of these 15 individuals (NL226 and NL259) were also sighted in West Lantau
waters during the HKLR09 monitoring surveys from March to May 2017, showing
their extensive individual movements across different survey areas.
Individual range use
3.5.44
Ranging patterns of the 15 individuals identified
during the three-month study period were determined by fixed kernel method, and
are shown in Annex V of Appendix J.
3.5.45
All identified dolphins sighted in the present
quarter were utilizing NWL waters only, but have completely avoided NEL waters
where many of them have utilized as their core areas in the past (Annex V of Appendix J). This is in contrary to the extensive
movements between NEL and NWL survey areas observed in the earlier impact
monitoring quarters as well as the baseline period.
3.5.46
On the other hand, two individuals (NL226 and
NL259) consistently utilized North Lantau waters in the past have extended
their range use to WL during the present quarter. 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 2015, 2016).
Action Level / Limit Level Exceedance
3.5.47
There was one Limit Level
exceedance of dolphin monitoring for the quarterly monitoring data (between
March 2017 ¡V May 2017). According to the contractor¡¦s information, the marine
activities undertaken for HKLR03 during the quarter of March 2017 ¡V May 2017
included removal of surcharge, road and drainage construction, seawall
construction, box culvert construction, and transportation of fill material.
3.5.48
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.
3.5.49
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.
3.5.50
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.
3.5.51
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).
3.5.52 For the comparison between the baseline period and the present quarter
(18th quarter of the impact phase being assessed), the p-values for
the differences in average dolphin encounter rates of STG and ANI were 0.0019
and 0.0186 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.
3.5.53 For comparison between the baseline period and the cumulative quarters in
impact phase (i.e. first eighteen quarters of the impact phase being assessed),
the p-values for the differences in average dolphin encounter rates of STG and
ANI were 0.000001 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).
3.5.54
The AFCD monitoring data
during March 2017 to May 2017 has been reviewed by the dolphin specialist. During the same quarter, no dolphin was
sighted from 54.18 km of survey effort on primary lines in NEL, while four
groups of 11 dolphins were sighted from 94.66 km of survey effort on primary
lines in NWL. This review has confirmed that the low occurrence of dolphins
reported by the HKLR03 monitoring surveys in spring 2017 in NEL and NWL survey
area is accurate.
3.5.55
All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Regular Marine Travel Route Plan, the travelling speed
of vessels must not exceed 5 knots when crossing the edge of the 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.
3.5.56
A meeting was held on 17
July 2017 with attendance of representative of ENPO, Resident Site Staff (RSS),
Environmental Team (ET) and dolphin specialist for Contract Nos. HY/2010/02,
HY/2011/03, HY/2012/07, HY/2012/08, and HY/2011/09. The discussion/
recommendation as recorded in the minutes of the meeting, which might be
relevant to HKLR03 Contract are summarized below.
3.5.57
It was concluded that the
HZMB works is one of the contributing factors affecting the dolphins. It was
also concluded the contribution of impacts due to the HZMB works as a whole (or
individual marine contracts) cannot be quantified nor separate from the other
stress factors.
3.5.58
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.
3.5.59
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.
3.5.60
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.
3.5.61 HyD updated that the draft map of the proposed BMP was gazetted in
February 2016. HyD updated that the draft map of the proposed Brothers Marine
Park (BMP) was gazetted in February 2016. ENPO updated that the BMP was
approved by the Chief Executive in the Executive Council in August 2016. The
ETs were reminded to update the BMP boundary in the Regular Marine Travel Route
(RMTR) Plan. The BMP was designated on 30 December 2016. It was suggested that
the protection measures (e.g. speed limit control) for the approved BMP shall
be brought forward so as to provide a better habitat for dolphin recovery. It
was noted that under the latest RMTR Plan, the contractors have committed to
reduce the vessel speed in BMP.
3.5.62
The marine travel route will shift along the
edge of Brother Marine Park as much as practical under the RMTR Plan. It was
noted that even though marine vessels may moor within the mooring site of BMP,
commercial activities including loading / unloading / transshipment are not
allowed except a permit is obtained. The HZMB works vessels were recommended to
avoid the BMP.
3.5.63 It was remined that starting from January 2016, HSF from the SkyPier will
be re-routed north to the northern edged of the Sha Chau and Lung Kwu Chau
Marine Park which currently has the highest density of CWD in the NWL. While
the HSF will reduce speed to 15 knots, the associated disturbance may still
affect CWD in the area. It was implied that the CWDs in the area shall be
closely followed.
3.5.64
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 28 March 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
(March 2017)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.163
|
816678.732
|
1.129
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.261
|
815831.516
|
0.992
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.590
|
815953.300
|
1.468
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.411
|
816151.399
|
1.118
|
Table 3.10 Comparison
of Measurement
|
Comparison of
measurement
|
Remarks and Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.003
|
0.005
|
0.179
|
Level continuously increased
|
S2
|
-0.011
|
-0.015
|
0.128
|
Level continuously increased
|
S3
|
0.005
|
-0.008
|
0.127
|
Level continuously increased
|
S4
|
-0.022
|
0.018
|
0.187
|
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
March 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-Mar-17
|
7.75
|
9.55
|
14.75
|
7.69
|
8.50
|
10.65
|
3-Mar-17
|
7.80
|
8.45
|
16.15
|
7.72
|
8.65
|
18.05
|
6-Mar-17
|
7.73
|
4.25
|
5.75
|
7.76
|
3.70
|
3.20
|
8-Mar-17
|
7.58
|
3.70
|
6.65
|
7.75
|
4.30
|
5.95
|
10-Mar-17
|
7.66
|
6.00
|
10.15
|
7.60
|
5.45
|
11.60
|
13-Mar-17
|
7.39
|
10.30
|
20.90
|
7.44
|
11.60
|
21.45
|
15-Mar-17
|
7.56
|
10.50
|
17.10
|
7.38
|
9.95
|
19.85
|
17-Mar-17
|
7.53
|
9.25
|
17.75
|
7.44
|
9.35
|
19.10
|
20-Mar-17
|
7.59
|
6.15
|
9.95
|
7.53
|
7.60
|
8.60
|
22-Mar-17
|
7.47
|
3.40
|
9.50
|
7.77
|
4.50
|
7.40
|
24-Mar-17
|
7.58
|
5.15
|
8.45
|
7.86
|
5.10
|
8.30
|
27-Mar-17
|
7.48
|
6.75
|
10.90
|
7.20
|
6.00
|
8.10
|
29-Mar-17
|
7.14
|
10.50
|
13.40
|
7.28
|
8.80
|
10.20
|
31-Mar-17
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
7.15
|
11.25
|
18.20
|
Average
|
7.56
|
7.23
|
12.42
|
7.54
|
7.48
|
12.19
|
Remark:
1) The water
quality monitoring (WQM) on 31 March 2017 during mid-ebb tide was cancelled for
safety reason as the thunderstorm signal was hoisted by Hong Kong Observatory
and lightning was recorded at the WQM stations.
|
Mudflat Ecology Monitoring
Sampling
Zone
3.6.6 In order to collect baseline information of
mudflats in the study site, the study site was divided into three sampling
zones (labeled as TC1, TC2, TC3) in Tung Chung Bay and one zone in San Tau
(labeled as ST) (Figure 2.1 of Appendix O). The horizontal shoreline of sampling
zones TC1, TC2, TC3 and ST were about 250 m, 300 m, 300 m and 250 m
respectively (Figure 2.2 of Appendix O).
Survey of horseshoe crabs, seagrass beds and intertidal communities were
conducted in every sampling zone. The present survey was conducted in March
2017 (totally 5 sampling days between 3rd and 14th March
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 5th (for TC1), 12th (for TC2) and 14th
(for TC3 and ST) March 2017. The weather was generally warm on 5th March while
it was windy on 12th and 14th March.
Seagrass Beds
3.6.9 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 5th (for TC1), 12th (for
TC2) and 14th (for TC3 and ST) March 2017. The weather was generally
warm on 5th March while it was windy on 12th and 14th
March.
Intertidal Soft Shore
Communities
3.6.10 The intertidal
soft shore community surveys were conducted in low tide period on 4th
(for ST), 5th (for TC1), 11th (for TC3) and 12th
(for TC2) March 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.
3.6.11
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 was
collected and identified. Finally, the top 5 cm surface sediments were dug for
visible infauna in the quadrat regardless of hand core sample was taken.
3.6.12
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.
3.6.13
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
3.6.14 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
3.6.15 In the present survey, two species of horseshoe
crab Carcinoscorpius rotundicauda
(total 44 ind.) and Tachypleus
tridentatus (total 16 ind.) were recorded. For one sight record, grouping
of 2-8 individuals was observed at same locations with similar substratum (fine
sand or soft mud). Photo records were shown in Figure 3.1 of Appendix O while the complete survey records were listed in Annex II of Appendix O.
3.6.16 Table
3.1 of Appendix O summarizes the survey results of horseshoe
crab in present survey. For Carcinoscorpius
rotundicauda, very few individuals were found in TC1 (4 ind.) and TC2 (1
ind., prosomal width 48.30 mm) only resulting in very low search record
(0.3-1.0 ind. hr-1 person-1). The average body size was
48.98 mm (prosomal width ranged 29.62-65.76 mm) in TC1. Relatively more
individuals were found in TC3 (16 ind.) and ST (23 ind.). The search record of
TC3 was 2.7 ind. hr-1 person-1 with average body size
37.59 mm (prosomal width ranged 16.89-70.29 mm). The search record of ST was
the higher (3.8 ind. hr-1 person-1) while the average
body size was 47.08 mm (prosomal width ranged 27.98-107.04 mm).
3.6.17 For Tachypleus tridentatus, there were only
5 and 11 individuals in TC3 and ST respectively. For TC3, the search record was
0.8 ind. hr-1 person-1 while the average body size was
40.99 mm (prosomal width ranged 29.54-50.66 mm). For ST, the search record was
higher (1.8 ind. hr-1 person-1) while the average body
size was 51.05 mm (prosomal width ranged 28.95-81.94 mm).
3.6.18 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.
Moreover, two moults of Carcinoscorpius
rotundicauda were found in TC1 with similar prosomal width 130-140 mm (Figure 3.2 of Appendix O). It reflected
that a certain numbers of moderately sized individuals inhabited the sub-tidal
habitat of Tung Chung Wan after its nursery period on soft shore. These
individuals might move onto soft shore during high tide for foraging, moulting
and breeding. Then it would return to sub-tidal habitat during ebb tide.
Because the mating pair should be inhabiting sub-tidal habitat in most of the
time. The record was excluded from the data analysis to avoid mixing up with
juvenile population living on soft shore. In another previous survey of Jun.
2016, the records of the two big individuals of Carcinoscorpius rotundicauda (prosomal width 117.37 mm and 178.17
mm) in TC1 were excluded from data analysis according to the same principle.
3.6.19 No marked individual of horseshoe crab was recorded
in present survey. Some marked individuals were found in previous surveys
conducted in Sep. 2013, Mar. 2014 and Sep. 2014. All of them were released
through a conservation programme conducted 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 crabs 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 September 2014.
3.6.20 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
3.6.21
Figures 3.3 and
3.4 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.
3.6.22
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. In the present survey (Mar. 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 during the survey.
3.6.23
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 and Mar.
2017).
3.6.24
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.
3.6.25 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.
Seasonal variation of horseshoe crab
population
3.6.26 Throughout the
monitoring period conducted, 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 search records were much
higher in Dec. 2016. There were totally 70 individuals of Carcinoscorpius rotundicauda and 24 individuals of Tachypleus tridentatus in TC3 and ST.
Because the survey was arranged in early December while the weather was warm
with sunlight (~22 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. In present survey (Mar. 2017),
there were only 44 individuals of Carcinoscorpius
rotundicauda and 16 individuals of Tachypleus
tridentatus recorded in Tung Chung Wan. All the surveys were conducted at
night while the ambient temperature was still low. Hence majority of horseshoe
crabs remained burrowing in sediments. Moreover, there was large scaled
recruitment of filamentious algae covering significant area of intertidal
mudflat in Tung Chung Wan (Figure 3.5 of
Appendix O). The algal cover would reduce the successful rate of active
searching.
3.6.27 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).
3.6.28
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 (present survey). 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. 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 located in TC3 and ST. Tachypleus tridentatus was a less common species while its
distribution was confined 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
3.6.29
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 and lower
quartile) ranged 40-60 mm while only few individuals were found. From Mar. 2014
to Mar. 2017 (present survey), the size of major population decreased and more
small individuals were recorded after Mar. of every year. It indicated new
rounds of successful breeding and spawning of Carcinoscorpius rotundicauda
in TC3. It matched with the previous mating record in ST in Mar. 2015. 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 much larger
individuals (circle dots above the box in the box plots), the size range was
quite variable (prosomal width 60-90 mm) along the sampling months. It was yet
to determine their size of migrating to sub-tidal habitat in TC3. Or larger
individuals might migrate northward to ST gradually.
3.6.30
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 Mar. 2017
(present survey), the major size decreased to 25-45 mm. Across the monitoring
period, the maximum prosomal width of major population ranged 60-80 mm. It
reflected individuals reaching this size would gradually migrate to sub-tidal
habitats.
Box plot of horseshoe crab populations in ST
3.6.31
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. 2016, the size of major population decreased and more
small individuals (i.e. circle dots below the box in the box plots) were
recorded after Jun. of every year. It indicated new round of successful
spawning in ST. It matched with the previous mating record in ST in Mar. 2015.
Also, there were slight increasing trends of body size from Sep. to Jun. from
2014 to 2016. It indicated a stable growth of individuals. Across the whole
monitoring period, the maximum prosomal width (i.e. circle dots above the box
in the box plots) usually ranged 70-80 mm except Mar. 2017 (present survey). It
reflected individuals reaching this size would gradually migrate to sub-tidal
habitats. In Mar. 2017, a large individual (prosomal width 107.04 mm) was
recorded that was believed a sub-tidal inhabitant move to intertidal shore
occasionally for foraging at night.
3.6.32
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 55-70 mm. As mentioned, the large individuals 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 individuals 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. From Dec. 2015 to 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 and further to 40-70 mm
in Mar. 2017 (present survey). Based on overall higher number of small
individuals recorded in Jun. and Sep. 2016, it indicated new round of
successful spawning in ST. Throughout the monitoring period, the maximum
prosomal width of major population ranged 60-80 mm. It reflected individuals
reaching this size would gradually migrate to sub-tidal habitats, similar to
the finding in TC3.
3.6.33
As a
summary for horseshoe crab populations in TC3 and ST, there was successful
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 TC3 and ST 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 successful
spawning was recorded in ST while increasing number of individuals and body
size was noticed.
Impact of the HKLR project
3.6.34
It was the 18th 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 successful spawnings 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
3.6.35
In the present survey, seagrass species Halophila ovalis and Zostera japonica were recorded in TC3
and ST. Photo records were shown in Figure
3.8 of Appendix O while the
complete records of seagrass beds survey were shown in Annex III of Appendix O.
3.6.36
Table 3.2 of Appendix I summarizes the results of
seagrass beds survey. In TC3, one small patch of Halophila ovalis was found in soft mud area at 0.5-1.0 m above C.D.
while the total seagrass bed area and vegetation coverage were about 43.3 m2
and 20% respectively.
3.6.37
In ST, four patches of Halophila ovalis were found while the total seagrass bed area was
about 12437.5 m2. The seagrass bed area was highly variable among
patches. In the soft mud area at 0.5-1.5 m above C.D., the largest patch was an
extensive, horizontal strand with area ~6521.9 m2 and vegetation coverage
20%. It had covered significant portion of the mud flat area in ST. At
vicinity, there was another extensive patch (3131.3 m2, coverage
50%). At higher tidal level (1.5-2.0 m above C.D.), there were two seagrass
patches in the sandy area nearby the seaward mangrove boundary. There were two
horizontal strand, medium patches with area 1345.4-1438.9 m2 and
vegetation coverage 50%.
3.6.38
For Zostera
japonica, there were two small patches only in the sandy area nearby the
seaward mangrove boundary. The seagrass bed area and vegetation coverage were
4.1-76.4 m2 and 50-100%.
3.6.39
Since
majority of seagrass bed was confined in ST, the temporal change of both
seagrass species was investigated in details.
Temporal variation
of seagrass beds
3.6.40
Figure 3.9 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 (80 m2) in Mar. 2017
(present survey). And it was no longer co-existing with Halophila ovalis.
From Sep. 2014 to Mar. 2017, an increasing trend was noticed from Sep. to Jun.
of next year followed by a rapid decline to Sep. It was possibly the causes of
heat stress, typhoon and stronger grazing pressure during wet season.
3.6.41 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.
3.6.42
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
unfavorable conditions (Fong, 1998).
Unfavourable
conditions to seagrass Halophila ovalis
3.6.43
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.
3.6.44 Prolonged light deprivation due to turbid water
would be another unfavorable 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).
3.6.45 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.
3.6.46 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 unfavorable condition in the coming months.
Recolonization of
seagrass beds
3.6.47
Figure 3.10 of Appendix O shows the
recolonization of seagrass bed area in ST from Dec. 2014 to Dec. 2016. 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. In Mar. 2017 (present survey),
the seagrass bed area remained stable (12438 m2) while the
vegetation coverage decreased clearly (20-50%). Such decline of seagrass bed
area might be similar to the record in Sep-Dec. 2014.
Impact of the HKLR project
3.6.48 It was the 18th
survey of the EM&A programme during the construction period. According to
the results of present survey, there was clear recolonization of both seagrass
species Halophila ovalis and Zostera japonica in ST. Hence the
negative impact of HKLR project on the seagrass was not significant. From Dec.
2016 to Mar. 2017 (present survey), a decline of seagrass bed was noted again
but it was yet to deduce the presence of stress factors. In case unfavorable
phenomenon (e.g. reduction of seagrass patch size, abnormal change of leave
color) is found persistent, it would be reported as soon as possible.
Intertidal Soft Shore Communities
3.6.49
Table 3.3 and Figure 3.11 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:
In TC1, high
percentages of ¡¥Gravels and Boulders¡¦ (80-90%) were recorded at all tidal
levels. The minor substratum types were 'Sands' (10-20% at high and mid tidal
levels) and 'Soft mud' (10% at low tidal level).
In TC2, the major
substratum types were ¡¥Sands¡¦ (90% at high tidal level) and 'Soft mud' (60-80%
at mid and low tidal levels). The minor substratum types were ¡¥Gravels and
Boulders¡¦ (30%) at mid tidal level and 'Sands' (20%) at low tidal level.
In TC3, ¡¥Sands¡¦
(50%) and 'Soft mud' (50%) were the usual substratum types at high tidal level.
Higher percentage of ¡¥Sands¡¦(70%) was recorded followed by 'Soft mud' (20%) at
mid tidal level. At low tidal level, the major substratum type was ¡¥Gravels and
Boulders¡¦ (100%).
In ST, high
percentages of ¡¥Gravels and Boulders¡¦ (80-100%) were recorded at high and mid
tidal levels. At low tidal level, the major substratum type was ¡¥Soft mud¡¦
(60%) followed by ' Gravels and Boulders¡¦ (30%).
3.6.50
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.
3.6.51
Table 3.4 of Appendix O lists the total abundance, density and
number of taxon of every phylum in this survey. A total of 11451 individuals
were recorded. Mollusca was clearly the most abundant phylum (total abundance
11153 ind., density 372 ind. m-2, relative abundance 97.4%). The
second and third abundant phyla were Arthropoda (182 ind., 6 ind. m-2,
1.6%) and Annelida (61 ind., 2 ind. m-2, 0.5%) 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 (35 taxa) followed by Arthropoda
(11 taxa) and Annelida (7 taxa). There were 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.
3.6.52
Table 3.5 of Appendix O shows
the number of individual, relative abundance and density of each phylum in
every sampling zone. The total abundance (1435-4154 ind.) varied among the four
sampling zones while the phyla distributions were similar. In general, Mollusca
was the most dominant phylum (no. of individuals: 1373-4074 ind.; relative
abundance 95.7-98.1%; density 183-543 ind. m-2). Other phyla were
significantly lower in number of individuals. Arthropoda was the second
abundant phylum (29-59 ind.; 1.2-2.2%; 4-8 ind. m-2). Annelida was
the third abundant phylum in TC1, TC2 and TC3 (14-27 ind.; 0.3-1.9%; 2-4 ind. m-2)
while Cnidaria (i.e. sea anemone) was the third abundant phylum in ST (12 ind.;
0.6%; 2 ind. m-2). Relatively other phyla were low in abundance in
all sampling zones (≤ 0.5%).
Dominant
species in every sampling zone
3.6.53
Table 3.6 of Appendix O
lists the abundant species (relative abundance >10%) in every sampling zone.
In the present survey, most of the listed abundant species were of low to
moderate densities (50-250 ind. m-2). There was one dominant species
of very high density (594 ind. m-2) at certain tidal level in one
sampling zone. Other listed species of lower density (< 50 ind. m-2)
were regared as common species.
3.6.54
In TC1,
gastropod Batillaria multiformis was
highly dominant at very high density (594 ind. m-2, relative
abundance 76%) at high tidal level (major substratum: ¡¥Gravels and Boulders¡¦).
At mid tidal level (major substratum: ¡¥Gravels and Boulders¡¦), gastropods Batillaria multiformis (240 ind. m-2,
49%), Monodonta labio (74 ind. m-2,
15%) and rock oyster Saccostrea cucullata
(78 ind. m-2, 16%, attached on boulders) were abundant at
low-moderate densities. At low tidal level (major substratum: ¡¥Gravels and
Boulders¡¦), rock oyster Saccostrea
cucullata (117 ind. m-2, 30%) was abundant at moderate density
followed by gastropods Monodonta labio
(82 ind. m-2, 21%) and Batillaria
multiformis (62 ind. m-2, 16%).
3.6.55
In TC2,
gastropods Cerithidea djadjariensis
(265 ind. m-2, 64%) was abundant at moderate densities at high tidal
level (major substratum: 'Sands'). Gastropods Cerithidea cingulata (48 ind. m-2, 12%) and Batillaria zonalis (41 ind. m-2,
10%) were common species at high tidal level. There was no clearly abundant
species at mid and low tidal levels. Rock oyster Saccostrea cucullata (5-38 ind. m-2, 19-29%) and
gastropod Batillaria zonalis (10-38
ind. m-2, 29-38%) were common at mid and low tidal levels (major
substratum: ¡¥Soft mud¡¦). Besides gastropod Cerithidea
djadjariensis (14 ind. m-2, 11%) and polychaete Maldanidae spp. (4 ind. m-2,
13%) were also common at mid and low tidal levels respectively.
3.6.56 In TC3, gastropods Cerithidea djadjariensis (238 ind. m-2,
44%) and Batillaria multiformis (235 ind. m-2, 43%) were
abundant at moderate densities at high tidal level (major substrata: ¡¥Sands¡¦
and 'Soft mud'). At mid tidal level (major substratum: ¡¥Sands¡¦), gastropod Cerithidea
djadjariensis (268 ind. m-2, 57%) was abundant at moderate
density followed by gastropods Batillaria multiformis (88 ind. m-2,
19%) and Cerithidea cingulata (49 ind. m-2, 10%). At low
tidal level (major substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea
cucullata (217 ind. m-2, 41%) was the most abundant at
moderate-high density followed by gastropod Monodonta labio (152 ind. m-2,
29%).
3.6.57
In ST,
gastropod Batillaria multiformis was
abundant at moderate density (113 ind. m-2, 33%) followed by Monodonta labio (66 ind. m-2,
19%) and rock oyster Saccostrea cucullata
(57 ind. m-2, 17%) at high tidal level (major substratum: ¡¥Gravels
and Boulders¡¦). At mid tidal level
(major substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea cucullata (124 ind. m-2, 34%) was abundant at
moderate density followed by common gastropods Monodonta labio (46 ind. m-2, 13%) and Lunella coronata (42 ind. m-2,
12%). No single species was abundant at low tidal level (major substratum:
¡¥Soft mud¡¦). The common species were rock oyster Saccostrea cucullata (31 ind. m-2, 29%) and gastropods Lunella coronata (16 ind. m-2,
15%) and Batillaria zonalis (14 ind.
m-2, 13%).
3.6.58
In
general, there was no consistent zonation pattern of species distribution
across all sampling zones and tidal levels. The species distribution should be
determined by the type of substratum primarily. In general, gastropods Batillaria multiformis (total number of
individuals: 3531 ind., relative abundance 30.8%), Cerithidea djadjariensis (2326 ind., 20.3%), Cerithidea cingulata (447 ind., 3.9%) and Batillaria zonalis (423 ind., 3.7%) were the most commonly
occurring species on sandy and soft mud substrata. Rock oyster Saccostrea cucullata (1760 ind., 15.4%),
gastropods Monodonta labio (1178
ind., 10.3%) and Lunella coronata (396
ind., 3.5%) were commonly occurring species inhabiting gravel and boulders
substratum.
Biodiversity and abundance of soft shore
communities
3.6.59 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.
3.6.60
Among the sampling
zones, the mean species number of TC1 and ST (10-11 spp. 0.25 m-2)
were slightly higher than that of TC2 and TC3 (6-8 spp. 0.25 m-2).
The mean densities of TC1 and TC3 (513-554 ind. m-2) were higher
than TC2 and ST (191-269 ind. m-2). Since the species distribution
of ST was more even relatively, the mean H¡¦
(1.6) and J (0.8) were higher than
that of TC1, TC2 and TC3 (H':
1.1-1.4, J: 0.5-0.7).
3.6.61
Across the tidal
levels, there was no consistent difference of the mean species number and H' in all sampling zones. For the mean
density, there were generally decreasing trends in TC1, TC2 and ST from high to
low tidal level. For the mean J,
there was a slightly increasing trend from high to low tidal level in all
sampling zones.
3.6.62
Figures 3.12 to 3.15 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.
3.6.63
Focusing on the changes of mean density in ST,
there were decreasing trends regardless of tidal levels. It might be an
unfavourable change that reflected environmental stresses. Since the total abundances
might restore after spring. More consolidated statements would be made after
the next wet season monitoring (Jun. 2017).
Impact of the HKLR project
3.6.64
It was the 18th 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. As mentioned
above, environmental stresses were yet to be confirmed based on the decreasing
trends of mean density in ST. The coming wet season survey results were important.
In case of other abnormal phenomena (e.g. rapid or consistent decline of fauna
densities and species number) are observed, it would be reported as soon as
possible.
3.7
Solid and Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical
Waste Producer on 12 July 2012 for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental Licenses and Permits
3.8.1
The valid environmental licenses and permits
during the reporting period are summarized in Appendix L.
4
Environmental Complaint and Non-compliance
4.1.1 The detailed air quality, noise, water
quality and dolphin exceedances are provided in Appendix M. Also, the summaries of the environmental
exceedances are presented as follows:
Air Quality
4.1.2
No Action Level
exceedances of 1-hr TSP were recorded at AMS5 and no Action and Limit Level
exceedances of 24-hr TSP were recorded at AMS5 and AMS6 during the reporting
period. Two Limit Level exceedances of 1-hr TSP level were recorded at AMS5
while two Action Level and one Limit Level exceedances of 1-hr TSP level were
recorded at AMS6 during the reporting period.
Noise
4.1.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
4.1.4 An Action Level exceedance of suspended solid was recorded at station
SR5 during mid-flood tide on 3 March 2017. Two Action Level exceedances of
turbidity level were recorded at stations SR4 and IS8 on 24 March 2017. Also,
an Action Level exceedance of suspended solid was recorded at station IS8
during mid-ebb tide and three Limit Level exceedances of suspended solid were
record at station SR4 during mid-ebb tide and at stations IS8 and SR4 during
mid-flood tide on 24 March 2017. An Action Level exceedance of suspended solid
was recorded at station IS8 during mid-ebb tide on 27 March 2017. No Limit
Level exceedances of turbidity level was recorded. No Action and Limit Level
exceedances of dissolved oxygen level was recorded.
Dolphin
4.1.5
There
was one Limit Level exceedance of dolphin monitoring for the quarterly
monitoring data (between March 2017 ¡V May 2017). According to the contractor¡¦s
information, the marine activities undertaken for HKLR03 during the quarter of
March 2017 ¡V May 2017 included removal of surcharge, road and drainage
construction, seawall construction, box culvert construction, and
transportation of fill material.
4.1.6
There
is no evidence showing the current LL non-compliance directly related to the
construction works of HKLR03 (where the amounts of working vessels for HKLR03
have been decreasing), although the generally increased amount of vessel
traffic in NEL during the impact phase has been partly contributed by HKLR03
works since October 2012. It should also be noted that reclamation work under
HKLR03 (adjoining the Airport Island) situates in waters which has rarely been
used by dolphins in the past, and the working vessels under HKLR03 have been
travelling from source to destination in accordance with the Marine Travel
Route to minimize impacts on Chinese White Dolphin (CWD). In addition, the contractor will
implement proactive mitigation measures such as avoiding anchoring at Marine Department¡¦s
designated anchorage site ¡V Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable.
4.1.7
All dolphin protective measures are fully and
properly implemented in accordance with the EM&A Manual. According to the
Regular Marine Travel Route Plan, the travelling speed of vessels must not
exceed 5 knots when crossing the edge of the 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 were five complaints 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-2017-108
|
23 February 2017and 2 March 2017
|
Cleanliness problem at East Coast Road
|
COM-2017-112
|
27 March 2017
|
Noise and Water Quality
|
COM-2017-113
|
20 April 2017
|
Water quality problem at Portion X
|
COM-2017-095(3)
|
27 May 2017
|
Noise nuisances near Dragonair / CNAC (Group)
Building (HKIA)
|
4.2.2 Complaint
investigations were undertaken. For Environmental Complaints Nos. COM-2017-108
and COM-2017-112, it was considered that the complaints were unlikely related
to Contract No. HY/2011/03. For Environmental Complaint No. COM-2017-113, it was
suspected that the concerned silt plume may be caused by sea current. There was
no evidence that the concerned silt plume was caused by any activities arising
from the Contract. For Environmental Complaint No. COM-2017-095(3), it
was considered that the complaint was likely related to Contract No.
HY/2011/03. The Contractor has implemented the following measures to minimize
the potential noise impact:
-
Additional noise barriers have been erected in
the active working area to further mitigate the associated noise emissions as
far as practicable;
-
Cover the breaker tip with acoustic material.
-
Noise barriers have been located as close as
possible to the noise source. Also, gaps and openings at joints in the barriers
material have been minimized.
-
Speed up of construction works in order to
shorten the duration noise impact/nuisance to the surrounding.
-
Minimize the quantities of noisy plant as far as
practicable.
-
Regular review of working duration and switch
off all unnecessary machinery and plant.
4.2.3
No notification of
summons and prosecution was received during the reporting period.
4.2.4 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 cement bags or cover the them using
impervious sheeting at HMA, Cut and Cover, and Ventilation Building.
¡P
The
Contractor was reminded to remove the blue hoses from S9.
¡P
The
Contractor was reminded to maintain or align the silt curtain properly at
Portion X.
¡P
The
Contractor was reminded to remove the waste from N1, S7, S9, S15, S25, PR14,
WA6, HMA, Cut and Cover, and Ventilation Building.
¡P
The
Contractor was reminded to remove the construction waste from the Ventilation
Building.
¡P
The
Contractor was reminded to remove the concrete waste from HMA.
¡P
The
Contractor was reminded to update the checklist for wastewater treatment
facilities at N1.
¡P
The
Contractor was reminded to provide drip tray for the chemical containers/oil
drums or remove them from PR9, Ying Lee Workshop, Cut and Cover, and Ventilation
Building.
¡P
The
Contractor was reminded to seal the gap of earth using sand bags at S7.
¡P
The
Contractor was reminded to provide sufficient water spraying for the road at
S25.
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 nineteenth Quarterly EM&A
Report which summarizes the monitoring results and audit findings of the
EM&A programme during the reporting period from 1 March 2017 to 31 May 2017.
Air Quality
5.3.2 No Action Level exceedances of 1-hr TSP were
recorded at AMS5 and no Action and Limit Level exceedances of 24-hr TSP were
recorded at AMS5 and AMS6 during the reporting period. Two Limit Level
exceedances of 1-hr TSP level were recorded at AMS5 while two Action Level and
one Limit Level exceedances of 1-hr TSP level were recorded at AMS6 during the
reporting period.
Noise
5.3.3
No Action and Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
5.3.4 An Action Level exceedance of suspended solid was recorded at station
SR5 during mid-flood tide on 3 March 2017. Two Action Level exceedances of
turbidity level were recorded at stations SR4 and IS8 on 24 March 2017. Also,
an Action Level exceedance of suspended solid was recorded at station IS8
during mid-ebb tide and three Limit Level exceedances of suspended solid were
record at station SR4 during mid-ebb tide and at stations IS8 and SR4 during
mid-flood tide on 24 March 2017. An Action Level exceedance of suspended solid
was recorded at station IS8 during mid-ebb tide on 27 March 2017. No Action and
Limit Level exceedances of dissolved oxygen level was recorded during the
reporting period.
Dolphin
5.3.5 There was a Limit Level exceedance of
dolphin monitoring for the quarterly monitoring data between March 2017 to May
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 from the important habitat
around the Brothers Islands.
5.3.8
It is
critical to continuously monitor the dolphin usage in North Lantau region in
the upcoming quarters, to determine whether the dolphins are continuously
affected by the various construction activities in relation to the HZMB-related
works, and whether suitable mitigation measure can be applied to revert the
situation.
Mudflat
-Sedimentation Rate
5.3.9
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.
Mudflat - Ecology
5.3.10
The March 2017 survey was the eighteenth 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 8, 15, 22 and 31 March 2017; 5,
12, 19 and 28 April 2017; and 4, 10, 17 and 26 May 2017.
Recommendations on remedial actions were given to the Contractors for the
deficiencies identified during the site inspections.
5.3.12
There were five complaints received in relation
to the environmental impacts during the reporting period. For
Environmental Complaints Nos. COM-2017-108 and COM-2017-112, it was considered
that the complaints were unlikely related to Contract No. HY/2011/03. For
Environmental Complaint No. COM-2017-113 mentioned in previously Monthly EM&A
Report for April 2017, it was suspected that the concerned silt plume may be
caused by sea current. There was no evidence that the concerned silt plume was
caused by any activities arising from the Contract. For Environmental Complaint
No. COM-2017-095(3), it is considered that the complaint is likely related to
Contract No. HY/2011/03. The Contractor has implemented mitigation measures to
minimize the potential noise impact.
5.3.13
No notification of summons and prosecution was
received during the reporting period.