Contents
Executive
Summary
1...... Introduction. 1
1.1 Basic Project Information. 1
1.2 Project Organisation. 1
1.3 Construction Programme. 1
1.4 Construction
Works Undertaken During the Reporting Period. 1
2....... EM&A Requirement 3
2.1 Summary
of EM&A Requirements. 3
2.2 Action and Limit Levels. 4
2.3 Event Action Plans. 5
2.4 Mitigation Measures. 5
3....... Environmental Monitoring
and Audit 6
3.1 Implementation of Environmental
Measures. 6
3.2 Air Quality Monitoring Results. 6
3.3 Noise Monitoring Results. 7
3.4 Water
Quality Monitoring Results. 7
3.5 Dolphin Monitoring Results. 8
3.6 Mudflat Monitoring Results. 19
3.7 Solid and Liquid Waste Management
Status. 32
3.8 Environmental Licenses and Permits. 32
4....... Environmental Complaint and Non-compliance. 33
4.1 Environmental Exceedances. 33
4.2 Summary of Environmental Complaint,
Notification of Summons and Successful Prosecution. 34
5....... Comments, Recommendations
and Conclusion. 35
5.1 Comments. 35
5.2 Recommendations. 35
5.3 Conclusions. 36
Figures
Figure 1.1 Location of the Site
Figure 2.1 Environmental
Monitoring Stations
Figure 2.2 Transect Line
Layout in Northwest and Northeast Lantau Survey Areas
Appendices
Appendix
A Environmental
Management Structure
Appendix
B Construction
Programme
Appendix
C Location
of Works Areas
Appendix D Event and
Action Plan
Appendix E Implementation
Schedule of Environmental Mitigation Measures
Appendix
F Site
Audit Findings and Corrective Actions
Appendix G Air Quality Monitoring Data and
Graphical Plots
Appendix H Noise Monitoring Data and
Graphical Plots
Appendix I Water
Quality Monitoring Data and Graphical Plots
Appendix J Dolphin
Monitoring Results
Appendix K Waste Flow
Table
Appendix
L Summary
of Environmental Licenses and Permits
Appendix M Record of
¡§Notification of Environmental Quality Limit Exceedances¡¨ and Record of
¡§Notification of Summons and Prosecutions¡¨
Appendix N Cumulative
Statistics on Complaints
Appendix
O Mudflat Monitoring Results
Executive Summary
The Hong
Kong-Zhuhai-Macao Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect
the HZMB Main Bridge at the Hong Kong Special Administrative Region (HKSAR)
Boundary and the HZMB Hong Kong Boundary Crossing Facilities (HKBCF) located at
the north eastern waters of the Hong Kong International Airport (HKIA).
The
HKLR project has been separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and
Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract)
and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China
State Construction Engineering (Hong Kong) Ltd. was awarded by Highways Department
as the Contractor to undertake the construction works of Contract No.
HY/2011/03. The main works of the Contract include land tunnel at Scenic Hill,
tunnel underneath Airport Road and Airport Express Line, reclamation and tunnel
to the east coast of the Airport Island, at-grade road connecting to the HKBCF
and highway works of the HKBCF within the Airport Island and in the vicinity of
the HKLR reclamation. The Contract
is part of the HKLR Project and HKBCF Project, these projects are considered to
be ¡§Designated Projects¡¨, under Schedule 2 of the Environmental Impact
Assessment (EIA) Ordinance (Cap 499) and EIA Reports (Register No.
AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project. The current Environmental Permit (EP)
EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF were issued on 22 December
2014 and 11 April 2016, respectively. These documents are available through the
EIA Ordinance Register. The construction phase of
Contract was commenced on 17 October 2012.
BMT
Hong Kong Limited has been appointed by the Contractor to implement the
Environmental Monitoring & Audit (EM&A) programme for the Contract in
accordance with the Updated EM&A Manual for HKLR (Version 1.0) and will be
providing environmental team services to the Contract.
This
is the twenty-fourth 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 June 2018 to 31 August 2018.
Environmental
Monitoring and Audit Progress
The EM&A programme were undertaken in
accordance with the Updated EM&A Manual for HKLR (Version 1.0). A summary of the monitoring activities
during this reporting period is presented as below:
Monitoring Activity
|
Monitoring
Date
|
June 2018
|
July 2018
|
August 2018
|
Air
Quality
|
1-hr
TSP
|
4, 8, 14, 20, 26 and 28
|
4, 10, 16, 20 and 26
|
1, 7, 13, 17, 23 and 29
|
24-hr
TSP
|
1, 7, 13, 19, 25 and 27
|
3, 9, 13, 19, and 25 for AMS5;
3, 9, 13, 19, 25 and 31 for AMS6
|
1, 8, 10, 16, 22 and 28
for AMS5;
6, 10,16, 22 and 28
for AMS6
|
Noise
|
4, 14, 20 and 26
|
4, 10, 16 and 26
|
1, 7, 13, 23 and 29
|
Water Quality
|
1, 4, 6, 11, 13, 15, 18, 20, 22, 25, 27 and 29
|
2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25, 27 and 30
|
1,
3, 6, 8, 10, 13, 15, 17, 20, 22, 24, 27, 29 and 31
|
Chinese
White Dolphin
|
5, 13, 19 and 27
|
3, 9, 12 and 20
|
1, 8, 21 and 28
|
Mudflat Monitoring (Ecology)
|
2, 3, 16, 17 and 27
|
-
|
-
|
Mudflat Monitoring (Sedimentation rate)
|
15
|
-
|
-
|
Site Inspection
|
6, 13, 20 and 29
|
4, 11, 18 and 27
|
1, 8, 15, 22 and 31
|
Due
to poor weather on 12 and 13 June 2018, the mudflat monitoring was rescheduled
to 16 and 27 June 2018 respectively.
Due
to unstable weather on 13 June 2018, the sedimentation rate monitoring was
rescheduled from 13 June 2018 to 15 June 2018.
Due
to the mechanical failure in the boat engine, the dolphin monitoring was
rescheduled from 26 June 2018 to 27 June 2018.
Due
to boat unavailability on 12 June 2018 and 17 July 2018, the dolphin monitoring
was rescheduled from 12 June 2018 to 13 June 2018 and 17 July 2018 to 20 July 2018.
Due to the bad weather
condition, the dolphin monitoring was rescheduled from 13 August 2018 to 28
August 2018 and from 15 August 2018 to 21 August 2018.
Due
to adverse weather condition (hoisting Tropical Cyclone Warning Signal, No. 1,
Thunderstorm Warning and Amber Rainstorm Warning Signal), water quality
monitoring for ebb tide on 6 June 2018 was cancelled due to safety reasons. The
water quality monitoring for flood tide on 6 June 2018 was also cancelled
except at stations SR10B(N2) and SR10A(N).
Due
to adverse weather condition (hoisting of Strong Wind Signal, No. 3), water
quality monitoring for both ebb and flood tides on 8 June 2018 were cancelled
due to safety reasons.
Thunderstorm
Warning and Amber Rainstorm Warning Signal were issued by Hong Kong Observatory
on 22 June 2018 and 22 August 2018. The water quality monitoring for flood tide at all stations on 22 June 2018 and the water quality monitoring at SR10A(N) and SR10B(N2)
for flood tide on 22 August 2018 was cancelled due to safety reason.
As the Strong Wind Signal No.3 was hoisted and Thunderstorm
Warning was issued by Hong Kong Observatory. The water quality monitoring for
flood tide on 18 July 2018 was cancelled due to safety reasons.
Thunderstorm Warning was issued by Hong Kong
Observatory on 2 July 2018, 10 and 20 August 2018. The water quality monitoring for ebb tide on 2 July 2018 and 20 August 2018; and the water quality monitoring for flood tide on 10
August 2018 were cancelled due to safety reasons.
Thunderstorm Warning was issued by the Hong
Kong Observatory on 6 August 2018. The water quality monitoring for flood tide
on 6 August 2018 was cancelled due to safety reason except at stations CS2(A),
SR3(N).and IS5.
The monitoring time for TSP monitoring on 31
July 2018 at AMS5 (Ma Wan Chung Village) was less than 24-hr due to power
interruption of the high volume sampler (HVS). The 24-hr TSP monitoring
was rescheduled from 31 July 2018 to 1 August 2018.
The monitoring time for TSP monitoring on 6
August 2018 at AMS5 (Ma Wan Chung Village) was less than 24-hr due to
malfunction of HVS. The 24-hr TSP monitoring was rescheduled from 6 August 2018
to 8 August 2018.
Breaches of Action and Limit Levels
A
summary of environmental exceedances for this reporting period is as follows:
Environmental Monitoring
|
Parameters
|
Action Level (AL)
|
Limit Level (LL)
|
Air Quality
|
1-hr
TSP
|
0
|
0
|
24-hr
TSP
|
0
|
1
|
Noise
|
Leq
(30 min)
|
1
|
0
|
Water Quality
|
Suspended
solids level (SS)
|
2
|
0
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
13
|
5
|
Dolphin Monitoring
|
Quarterly
Analysis (Jun 2018 to Aug 2018)
|
0
|
1
|
All
investigation reports for exceedances of the Contract have been submitted to
ENPO/IEC for comments and/or follow up to identify whether the exceedances
occurred related to other HZMB contracts.
Implementation of Mitigation Measures
Site
inspections were carried out on a weekly basis to monitor the implementation of
proper environmental pollution control and mitigation measures for the Project.
Potential environmental impacts due to the construction activities were
monitored and reviewed.
Complaint Log
A complaint (Complaint No. COM-2018-142) in relation to the environmental
impacts (Noise impact) was received on 29 June 2018. A further
complaint related to same issue was received on 6 July 2018.
Based
on our investigation result, the complaint was related to Contract No. HY/2011/03.
A summary of
environmental complaint for June 2018 and July 2018 is as follows:
A
summary of environmental complaints for the reporting period is as follows:
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaint
|
Complaint
No. COM-2018-142
|
EPD
(ENPO referred the email to
SOR, Contractor
and ET on 29 June
2018 and 6 July
2018)
|
Noise
|
Notifications of Summons
and Prosecutions
There
were no notifications of summons or prosecutions received during this reporting
period.
Reporting Changes
This
report has been developed in compliance with the reporting requirements for the
subsequent EM&A reports as required by the Updated EM&A Manual for HKLR
(Version 1.0).
The
proposal for the change of Action Level and Limit Level for suspended solid and
turbidity was approved by EPD on 25 March 2013.
The
revised Event and Action Plan for dolphin monitoring was
approved by
EPD on 6 May 2013.
The original
monitoring station at IS(Mf)9 (Coordinate: 813273E, 818850N) was observed
inside the perimeter silt curtain of Contract HY/2010/02 on 1 July 2013, as
such the original impact water quality monitoring location at IS(Mf)9 was
temporarily shifted outside the silt curtain. As advised by the Contractor of HY/2010/02 in
August 2013, the perimeter silt curtain was shifted to facilitate safe
anchorage zone of construction barges/vessels until end of 2013 subject to
construction progress. Therefore,
water quality monitoring station IS(Mf)9 was shifted to 813226E and 818708N
since 1 July 2013. According to the
water quality monitoring team¡¦s observation on 24 March 2014, the original
monitoring location of IS(Mf)9 was no longer enclosed by the perimeter silt
curtain of Contract HY/2010/02. Thus, the impact water quality monitoring works
at the original monitoring location of IS(Mf)9 has been resumed since 24 March
2014.
Transect
lines 1, 2, 7, 8, 9 and 11 for dolphin monitoring have been revised due to the obstruction
of the permanent structures associated with the construction works of HKLR and
the southern viaduct of TM-CLKL, as well as provision of adequate buffer
distance from the Airport Restricted Areas. The EPD issued a memo and confirmed that
they had no objection on the revised transect lines on 19 August 2015.
The
water quality monitoring stations at IS10 (Coordinate: 812577E, 820670N) and
SR5 (811489E, 820455N) are located inside Hong Kong International Airport
(HKIA) Approach Restricted Areas. The previously granted Vessel's Entry Permit
for accessing stations IS10 and SR5 were expired on 31 December 2016. During
the permit renewing process, the water quality monitoring location was shifted
to IS10(N) (Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E,
820978N) on 2, 4 and 6 January 2017 temporarily. The permit has been granted by
Marine Department on 6 January 2017. Thus, the impact water quality monitoring
works at original monitoring location of IS10 and SR5 has been resumed since 9 January
2017.
Transect
lines 2, 3, 4, 5, 6 and 7 for dolphin monitoring have been revised and transect
line 24 has been added due to the presence of a work zone to the north of the
airport platform with intense construction activities in association with the
construction of the third runway expansion for the Hong Kong International
Airport. The EPD issued a memo and confirmed that they had no objection on the
revised transect lines on 28 July 2017. The alternative dolphin transect lines
are adopted starting from August¡¦s dolphin monitoring.
A
new water quality monitoring team has been employed for carrying out water
quality monitoring work for the Contract starting from 23 August 2017. Due to
marine work of the Expansion of Hong Kong International Airport into a
Three-Runway System (3RS Project), original locations of water quality
monitoring stations CS2, SR5 and IS10 are enclosed by works boundary of 3RS
Project. Alternative impact water quality monitoring stations, naming as
CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and were adopted
starting from 23 August 2017 to replace the original locations of water quality
monitoring for the Contract.
The
role and responsibilities as the ET Leader of the Contract was temporarily
taken up by Mr Willie Wong instead of Ms Claudine Lee from 25 September 2017 to
31 December 2017.
The
topographical condition of the water monitoring stations SR3 (Coordinate:
810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A (Coordinate:
823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot be accessed
safely for undertaking water quality monitoring. The water quality monitoring
has been temporarily conducted at alternative stations, namely SR3(N)
(Coordinate 810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and
SR10A(N) (Coordinate: 823644E, 823484N) since 1 September 2017. The water
quality monitoring at station SR10B was temporarily conducted at Coordinate:
823683E, 823187N on 1, 4, 6, 8 September 2017 and has been temporarily
fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E, 823159N)
since 11 September 2017. Proposal for permanently relocating the aforementioned
stations was approved by EPD on 8 January 2018.
According to latest
information received in July 2018, the works area WA7 was handed over to other
party on 28 February 2018 instead of 31 January 2018.
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)
|
June 2018
|
AMS5
|
25
|
6 ¡V 74
|
352
|
500
|
AMS6
|
27
|
14 ¡V 57
|
360
|
July 2018
|
AMS5
|
9
|
4 ¡V 18
|
352
|
AMS6
|
12
|
6 ¡V 16
|
360
|
August 2018
|
AMS5
|
16
|
5 ¡V 61
|
352
|
AMS6
|
24
|
5 ¡V 90
|
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)
|
June 2018
|
AMS5
|
33
|
18 ¡V 55
|
164
|
260
|
AMS6
|
116
|
32 ¡V 382
|
173
|
July 2018
|
AMS5
|
28
|
19 ¡V 40
|
164
|
AMS6
|
48
|
17 ¡V 99
|
173
|
August 2018
|
AMS5
|
24
|
17 ¡V 38
|
164
|
AMS6
|
39
|
20 ¡V 74
|
173
|
3.2.2
No Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5
and AMS6 during the reporting period. No Action and Limit Level exceedances of
24-hr TSP were recorded at AMS5. One Limit Level exceedance of 24-hr TSP was
recorded at AMS6 during the reporting period.
3.2.3
Record of
notification of environmental quality limit exceedances are provided in Appendix M.
3.3
Noise
Monitoring Results
3.3.1
The monitoring results for construction noise are
summarized in Table 3.3 and the monitoring
results and relevant graphical plots for this reporting period are provided in Appendix H.
Table 3.3 Summary of Construction Noise Monitoring Results
Obtained During the Reporting Period
Reporting period
|
Monitoring Station
|
Average Leq (30 mins),
dB(A)*
|
Range of Leq (30
mins), dB(A)*
|
Action Level
|
Limit Level Leq (30
mins), dB(A)
|
June 2018
|
NMS5
|
57
|
55 ¡V 59
|
When one documented complaint is received
|
75
|
July 2018
|
60
|
59 ¡V 61
|
August 2018
|
57
|
54 ¡V 59
|
3.3.2 An Action Level exceedance was recorded as a complaint was
received during reporting period. No Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
3.3.3
Major noise sources during the noise monitoring
included construction activities of the Contract and nearby traffic noise and
insect noise.
3.4.1 Impact water quality
monitoring was conducted at all designated monitoring stations during the
reporting period. Impact water quality monitoring results and relevant
graphical plots are provided in Appendix I.
3.4.1
3.4.2 No Action and Limit Level exceedances of turbidity level and no
Action Level exceedances of suspended solids level were recorded during
reporting period. 13 Action Level exceedances and 5 Limit Level of dissolved
oxygen level were recorded during the reporting period. 2 Action Level
exceedances of suspended solids level were recorded during the reporting
period. The exceedances of dissolved oxygen and suspended solids level recorded
during reporting period were considered to be attributed to other external
factors such as sea condition, rather than the contract works. The exceedances
were considered as non-contract related. Record of ¡§Notification of
Environmental Quality Limit Exceedances¡¨ is provided in Appendix M.
3.4.3
Water quality impact sources during the water quality
monitoring were the construction activities of the Contract, nearby
construction activities by other parties and nearby operating vessels by other
parties.
Data Analysis
3.5.1
Distribution
Analysis ¡V The line-transect survey data was integrated with the Geographic Information
System (GIS) in order to visualize and interpret different spatial and temporal
patterns of dolphin distribution using sighting positions. Location data of dolphin groups were
plotted on map layers of Hong Kong using a desktop GIS (ArcView© 3.1)
to examine their distribution patterns in details. The dataset was also
stratified into different subsets to examine distribution patterns of dolphin
groups with different categories of group sizes, young calves and activities.
3.5.2 Encounter
rate analysis ¡V Encounter rates of Chinese white dolphins (number of on-effort
sightings per 100 km of survey effort, and total number of dolphins sighted
on-effort per 100 km of survey effort) were calculated in NEL and NWL survey
areas in relation to the amount of survey effort conducted during each month of
monitoring survey. Dolphin
encounter rates were calculated in two ways for comparisons with the HZMB
baseline monitoring results as well as to AFCD long-term marine mammal monitoring
results.
3.5.3 Firstly,
for the comparison with the HZMB baseline monitoring results, the encounter
rates were calculated using primary survey effort alone, and only data
collected under Beaufort 3 or below condition would be used for encounter rate
analysis. The average encounter
rate of sightings (STG) and average encounter rate of dolphins (ANI) were
deduced based on the encounter rates from six events during the present quarter
(i.e. six sets of line-transect surveys in North Lantau), which was also
compared with the one deduced from the six events during the baseline period
(i.e. six sets of line-transect surveys in North Lantau).
3.5.4 Secondly,
the encounter rates were calculated using both primary and secondary survey
effort collected under Beaufort 3 or below condition as in AFCD long-term
monitoring study. The encounter
rate of sightings and dolphins were deduced by dividing the total number of
on-effort sightings (STG) and total number of dolphins (ANI) by the amount of
survey effort for the present quarterly period.
3.5.5 Quantitative
grid analysis on habitat use ¡V To conduct quantitative grid analysis of habitat
use, positions of on-effort sightings of Chinese White Dolphins collected
during the quarterly impact phase monitoring period were plotted onto 1-km2
grids among NWL and NEL survey areas on GIS. Sighting densities (number of on-effort
sightings per km2) and dolphin densities (total number of dolphins
from on-effort sightings per km2) were then calculated for each 1 km
by 1 km grid with the aid of GIS.
Sighting density grids and dolphin density grids were then further
normalized with the amount of survey effort conducted within each grid. The total amount of survey effort spent
on each grid was calculated by examining the survey coverage on each
line-transect survey to determine how many times the grid was surveyed during
the study period. For example, when
the survey boat traversed through a specific grid 50 times, 50 units of survey
effort were counted for that grid.
With the amount of survey effort calculated for each grid, the sighting
density and dolphin density of each grid were then normalized (i.e. divided by
the unit of survey effort).
3.5.6
The newly-derived unit for sighting density was
termed SPSE, representing the number of on-effort sightings per 100 units of
survey effort. In addition, the
derived unit for actual dolphin density was termed DPSE, representing the
number of dolphins per 100 units of survey effort. Among the 1-km2 grids that
were partially covered by land, the percentage of sea area was calculated using
GIS tools, and their SPSE and DPSE values were adjusted accordingly. The following formulae were used to
estimate SPSE and DPSE in each 1-km2 grid within the study area:
SPSE = ((S / E) x 100) / SA%
DPSE = ((D / E) x 100) / SA%
where S
= total number of on-effort sightings
D = total number of dolphins from on-effort sightings
E = total number of units of survey effort
SA% = percentage of sea area
3.5.7
Behavioural analysis ¡V When dolphins were sighted
during vessel surveys, their behaviour was observed. Different activities were categorized
(i.e. feeding, milling/resting, traveling, socializing) and recorded on
sighting datasheets. This data was
then input into a separate database with sighting information, which can be
used to determine the distribution of behavioural data with a desktop GIS. Distribution of sightings of dolphins
engaged in different activities and behaviours would then be plotted on GIS and
carefully examined to identify important areas for different activities of the
dolphins.
3.5.8
Ranging pattern analysis ¡V Location data of
individual dolphins that occurred during the 3-month baseline monitoring period
were obtained from the dolphin sighting database and photo-identification
catalogue. To deduce home ranges
for individual dolphins using the fixed kernel methods, the program Animal
Movement Analyst Extension, was loaded as an extension with ArcView©
3.1 along with another extension Spatial Analyst 2.0. Using the fixed kernel method, the
program calculated kernel density estimates based on all sighting positions,
and provided an active interface to display kernel density plots. The kernel estimator then calculated and
displayed the overall ranging area at 95% UD level.
Summary of Survey Effort and Dolphin
Sightings
3.5.9 During the period of June to
August 2018, six sets of systematic line-transect vessel
surveys were conducted to cover all transect lines in NWL and NEL survey areas
twice per month.
3.5.10 From these surveys, a total
of 771.98 km of
survey effort was collected, with 96.8% of the total survey effort being conducted under favorable weather
conditions (i.e. Beaufort Sea State 3 or below with good visibility). Among the two areas, 287.18 km and 484.80 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 567.73 km, while the effort on secondary lines was 204.25
km. Survey effort conducted on both primary and secondary lines were considered as on-effort survey data.
A summary table of the survey
effort is shown in Appendix J.
3.5.12 During the six sets of
monitoring surveys conducted between June and August
2018, seven groups of 17 Chinese White Dolphins were sighted, with
the summary table of the dolphin sightings shown in Annex II of Appendix J. Six of the seven dolphin sightings were made during on-effort search, while
four of the six on-effort dolphin sightings were made on primary lines.
3.5.13 In addition, all dolphin groups were sighted in
NWL, and no dolphin was sighted at all in NEL. In fact, since August 2014, only two
sightings of two lone dolphins were made respectively in NEL during HKLR03
monitoring surveys.
Distribution
3.5.14 Distribution of dolphin
sightings made during HKLR03 monitoring surveys conducted from June to August 2018 is shown in Figure 1 of Appendix J. All sightings were made
at the northwestern and southwestern ends of the North
Lantau region, especially near the mouth of Deep Bay
and the HKLR09 alignment (Figure 1 of
Appendix J). Only one sighting
was made near Lung Kwu Chau, even though this area was frequented by dolphins
throughout the construction monitoring period in the past several years (Figure 1 of Appendix
J).
3.5.15 As
consistently recorded in the previous monitoring quarters, the dolphins were
completely absent from the central and eastern portions of North Lantau waters
(Figure 1 of
Appendix J). Moreover, all dolphin sightings were
located far away from the HKLR03 and HKBCF reclamation sites as well as along the alignment of
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 (June-August 2018) was drastically
different from the one during the baseline monitoring period (Figure 1 of Appendix J).
In the present quarter, dolphins have disappeared from the NEL region,
which was in stark contrast to their frequent occurrence around the Brothers
Islands, near Shum Shui Kok and in the vicinity of HKBCF reclamation site
during the baseline period (Figure 1 of Appendix J). The nearly complete abandonment of NEL
region by the dolphins has been consistently recorded in the past 21 quarters
of HKLR03 monitoring, which has resulted in zero to extremely low dolphin
encounter rates in this area.
3.5.17 In NWL survey area, dolphin occurrence was also
significantly different between the baseline and impact phase periods. During the present impact monitoring
period, dolphins were seldom sighted
here, and mainly at the northwestern and southwestern
ends of the area, which was in stark
contrast to their frequent occurrences throughout the area
during the baseline period (Figure 1 of Appendix J).
3.5.18 Another comparison in dolphin distribution was made
between the six quarterly periods of summer months in 2013-18 (Figure 2 of Appendix J). Among the six summer periods, dolphins
were regularly sighted in NWL waters in 2013 and 2014, but their usage there
was dramatically reduced in the four subsequent summer periods, with their only
occurrences mostly concentrated at the western end of the survey area (Figure 2 of Appendix J). Moreover, in the summer of 2018,
dolphins were rarely sighted within the Sha Chau and Lung Kwu Chau Marine
Park, which was very
different from the previous five summer periods (Figure 2 of Appendix J).
Encounter Rate
3.5.19 During the present three-month study
period, the encounter rates of Chinese White Dolphins deduced from the survey
effort and on-effort sighting data from the primary transect lines under
favourable conditions (Beaufort 3 or below) for each set of the surveys in NEL
and NWL are shown in Table 3.4. The average encounter rates deduced from the
six sets of surveys were also compared with the ones deduced from the baseline
monitoring period (September ¡V November 2011) (Table 3.5).
3.5.20 To facilitate the comparison with the AFCD long-term monitoring results,
the encounter rates were also calculated for the present quarter using both
primary and secondary survey effort.
The encounter
rates of sightings (STG) and dolphins (ANI) in NWL were 1.30 sightings
and 3.48 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
(June
¡V August 2018)
Survey Area
|
Dolphin
Monitoring
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
Primary Lines Only
|
Primary Lines Only
|
Northeast Lantau
|
Set 1 (5 & 13 Jun 2018)
|
0.00
|
0.00
|
Set 2 (19 & 27 Jun 2018)
|
0.00
|
0.00
|
Set 3 (3 & 8 Jul 2018)
|
0.00
|
0.00
|
Set 4 (12 & 20 Jul 2018)
|
0.00
|
0.00
|
Set 5 (1 & 8 Aug 2018)
|
0.00
|
0.00
|
Set 6 (21 & 28 Aug 2018)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (5 & 13 Jun 2018)
|
0.00
|
0.00
|
Set 2 (19 & 27 Jun 2018)
|
1.91
|
3.81
|
Set 3 (3 & 8 Jul 2018)
|
0.00
|
0.00
|
Set 4 (12 & 20 Jul 2018)
|
1.68
|
6.71
|
Set 5 (1 & 8 Aug 2018)
|
3.36
|
6.72
|
Set 6 (21 & 28 Aug 2018)
|
0.00
|
0.00
|
Table 3.5 Comparison of average dolphin encounter rates from impact
monitoring period (June to August 2018) and baseline monitoring period
(September ¡V November 2011)
Survey Area
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey
effort)
|
Reporting Period
|
Baseline Monitoring Period
|
Reporting Period
|
Baseline Monitoring Period
|
Northeast Lantau
|
0.0
|
6.00 ¡Ó 5.05
|
0.0
|
22.19 ¡Ó 26.81
|
Northwest Lantau
|
1.16 ¡Ó 1.39
|
9.85 ¡Ó 5.85
|
2.87 ¡Ó 3.32
|
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
21 quarters of HKLR03 monitoring (Table
3.6). This is a serious concern as the dolphin occurrence in NEL in the past
few years (0.0-1.0 for ER(STG) and 0.0-3.9 for ER(ANI)) have remained
exceptionally low when compared to the baseline period (Table 3.6). Dolphins
have been virtually absent from NEL waters since January 2014, with only three
groups of six dolphins sighted there since then despite consistent and
intensive survey effort being conducted in this survey area.
Table 3.6 Comparison of Average Dolphin Encounter Rates in
Northeast Lantau Survey Area from All Quarters of Impact Monitoring Period and
Baseline Monitoring Period (Sep ¡V Nov 2011)
Monitoring Period
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
September-November
2011 (Baseline)
|
6.00 ¡Ó 5.05
|
22.19 ¡Ó 26.81
|
December 2012-February 2013 (Impact)
|
3.14 ¡Ó 3.21
|
6.33 ¡Ó 8.64
|
March-May 2013
(Impact)
|
0.42 ¡Ó
1.03
|
0.42 ¡Ó
1.03
|
June-August 2013 (Impact)
|
0.88 ¡Ó 1.36*
|
3.91 ¡Ó 8.36*
|
September-November 2013 (Impact)
|
1.01 ¡Ó 1.59
|
3.77 ¡Ó 6.49
|
December 2013-February 2014 (Impact)
|
0.45 ¡Ó 1.10
|
1.34 ¡Ó 3.29
|
March-May 2014
(Impact)
|
0.00
|
0.00
|
June-August 2014 (Impact)
|
0.42 ¡Ó 1.04*
|
1.69 ¡Ó 4.15*
|
September-November 2014 (Impact)
|
0.00
|
0.00
|
December 2014-February 2015 (Impact)
|
0.00
|
0.00
|
March-May 2015
(Impact)
|
0.00
|
0.00
|
June-August 2015 (Impact)
|
0.44 ¡Ó 1.08*
|
0.44 ¡Ó 1.08*
|
September-November 2015 (Impact)
|
0.00
|
0.00
|
December 2015-February 2016 (Impact)
|
0.00
|
0.00
|
March-May 2016
(Impact)
|
0.00
|
0.00
|
June-August 2016 (Impact)
|
0.00*
|
0.00*
|
September-November 2016 (Impact)
|
0.00
|
0.00
|
December 2016-February 2017 (Impact)
|
0.00
|
0.00
|
March-May 2017
(Impact)
|
0.00
|
0.00
|
June-August 2017 (Impact)
|
0.00*
|
0.00*
|
September-November 2017 (Impact)
|
0.00
|
0.00
|
December 2017-February 2018 (Impact)
|
0.00
|
0.00
|
March-May 2018
(Impact)
|
0.00
|
0.00
|
June-August 2018 (Impact)
|
0.00*
|
0.00*
|
Notes:
1) The encounter rates deduced from the baseline monitoring period have
been recalculated based only on survey effort and on-effort sighting data made along
the primary transect lines under favourable conditions.
2) ¡Ó denotes the standard deviation of the average
encounter rates.
3) The encounter rates in summer 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 88.2% and
93.5% respectively) were only tiny fractions of the ones recorded during the
three-month baseline period, indicating a dramatic decline in dolphin usage of
this survey area as well during the present impact phase period (Table 3.7).
Table 3.7 Comparison
of Average Dolphin Encounter Rates in Northwest Lantau Survey Area from All
Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep ¡V Nov
2011)
Monitoring Period
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per
100 km of survey effort)
|
Encounter rate (ANI)
(no.
of dolphins from all on-effort sightings per 100 km of survey effort)
|
September-November 2011 (Baseline)
|
9.85 ¡Ó 5.85
|
44.66 ¡Ó 29.85
|
December 2012-February 2013 (Impact)
|
8.36 ¡Ó 5.03
|
35.90 ¡Ó 23.10
|
March-May 2013 (Impact)
|
7.75 ¡Ó 3.96
|
24.23 ¡Ó 18.05
|
June-August
2013 (Impact)
|
6.56 ¡Ó 3.68*
|
27.00 ¡Ó 18.71*
|
September-November 2013 (Impact)
|
8.04 ¡Ó 1.10
|
32.48 ¡Ó 26.51
|
December 2013-February 2014 (Impact)
|
8.21 ¡Ó 2.21
|
32.58 ¡Ó 11.21
|
March-May 2014 (Impact)
|
6.51 ¡Ó 3.34
|
19.14 ¡Ó 7.19
|
June-August
2014 (Impact)
|
4.74 ¡Ó 3.84*
|
17.52 ¡Ó 15.12*
|
September-November 2014 (Impact)
|
5.10 ¡Ó 4.40
|
20.52 ¡Ó 15.10
|
December 2014-February 2015 (Impact)
|
2.91 ¡Ó 2.69
|
11.27 ¡Ó 15.19
|
March-May 2015 (Impact)
|
0.47 ¡Ó 0.73
|
2.36 ¡Ó 4.07
|
June-August
2015 (Impact)
|
2.53 ¡Ó 3.20*
|
9.21 ¡Ó 11.57*
|
September-November 2015 (Impact)
|
3.94 ¡Ó 1.57
|
21.05 ¡Ó 17.19
|
December 2015-February 2016 (Impact)
|
2.64 ¡Ó 1.52
|
10.98 ¡Ó 3.81
|
March-May 2016 (Impact)
|
0.98 ¡Ó 1.10
|
4.78 ¡Ó 6.85
|
June-August
2016 (Impact)
|
1.72 ¡Ó 2.17*
|
7.48 ¡Ó 10.98*
|
September-November 2016 (Impact)
|
2.86 ¡Ó 1.98
|
10.89 ¡Ó 10.98
|
December 2016-February 2017 (Impact)
|
3.80 ¡Ó 3.79
|
14.52 ¡Ó 17.21
|
March-May 2017 (Impact)
|
0.93 ¡Ó 1.03
|
5.25 ¡Ó 9.53
|
June-August
2017 (Impact)
|
2.20 ¡Ó 2.88*
|
6.58 ¡Ó 8.12*
|
September-November 2017 (Impact)
|
3.12 ¡Ó 1.91
|
10.35 ¡Ó 9.66
|
December 2017-February 2018 (Impact)
|
4.75 ¡Ó 2.26
|
15.73 ¡Ó 15.94
|
March-May 2018 (Impact)
|
2.88 ¡Ó 4.81
|
11.12 ¡Ó 22.46
|
|
June-August
2018 (Impact)
|
1.16 ¡Ó 1.39*
|
2.87 ¡Ó 3.32*
|
|
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 summer months were in blue and marked with asterisk.
3.5.23 Notably, the ER(STG) and ER(ANI) in the present quarter were the
fourth and second lowest respectively among all quarters during the entire
HKLR03 construction period.
Moreover, when comparing the quarterly periods in summer months, the
quarterly encounter rates in the summer of 2018 were the lowest among all
summer periods during the HKLR03 construction phase. The dramatic drop in
dolphin occurrence during this quarter should raise some concerns, and such
temporal trend should be closely monitored in the upcoming monitoring quarters
as the construction activities of HZMB works continue to diminish in coming
months.
3.5.24 A two-way ANOVA with repeated measures and unequal sample size was
conducted to examine whether there were any significant differences in the
average encounter rates between the baseline and impact monitoring
periods. The two variables that
were examined included the two periods (baseline and impact phases) and two
locations (NEL and NWL).
3.5.25 For the comparison between the baseline period and the present
quarter (23rd quarter of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.0022 and 0.0144 respectively. If the alpha value is set at 0.05,
significant differences were detected between the baseline and present quarters
in both the average dolphin encounter rates of STG and ANI.
3.5.26 For the comparison between the baseline period and the cumulative
quarters in impact phase (i.e. the first 23 quarters of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.000000 and 0.000000 respectively. Even if the alpha value is set at
0.00001, significant differences were still detected in both the average
dolphin encounter rates of STG and ANI (i.e. between the two periods and the
locations).
3.5.27 As indicated in both dolphin distribution patterns and encounter
rates, dolphin usage has been significantly reduced in both NEL and NWL survey
areas during the present quarterly period when compared to the baseline period,
and such low occurrence of dolphins has also been consistently documented in
previous quarters of the past few years.
3.5.28 The significant decline in dolphin usage of North Lantau region
raises serious concern, as the timing of the decline in dolphin usage in North
Lantau waters coincided well with the construction schedule of the HZMB-related
projects (Hung 2018). Apparently
there was very little sign of recovery of dolphin usage, even though almost all
marine works associated with the HZMB construction have been completed.
Group Size
3.5.29 Group size of Chinese White Dolphins ranged from one to five
individuals per group in North Lantau region during June to August 2018. The
average dolphin group sizes from these three months were compared with the ones
deduced from the baseline period in September to November 2011, as shown in
Table 3.8.
Table
3.8 Comparison
of Average Dolphin Group Sizes between Reporting Period (Jun ¡V Aug 2018) and Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average Dolphin Group Size
|
Reporting Period
|
Baseline Monitoring Period
|
Overall
|
2.43
¡Ó 1.62 (n = 7)
|
3.72
¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
2.43 ¡Ó 1.62 (n = 7)
|
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 June to August 2018
was lower than the one recorded during the three-month baseline period, but it
should be noted that the sample size of seven dolphin groups in the present
quarter was very small when compared to the 66 groups sighted during the
baseline period (Table 3.8).
3.5.31 Notably, with the exception of a medium-sized group with five
animals, the other six dolphin groups were small and composed of 1-4
individuals only (Annex II of Appendix J).
Distribution of the lone
larger dolphin group with five individuals during the present quarter is shown
in Figure 3 of Appendix
J, with comparison to the
one in baseline period. That
medium-sized dolphin group sighted in the present quarter was located at the
mouth of Deep Bay near Black Point (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 (especially around the Sha Chau and Lung Kwu Chau Marine Park), and a
few were also sighted in NEL waters (Figure
3 of Appendix J).
Habitat
Use
3.5.32 From
June to August 2018, only five grids that recorded dolphin occurrence, and the grids with moderately high dolphin densities
were located at the mouth of Deep Bay and near the HKLR09 alignment (Figures 4a and 4b of Appendix J).
3.5.33 Notably,
all grids near HKLR03/HKBCF reclamation sites as well as 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).
3.5.34
It should be emphasized that the amount of
survey effort collected in each grid during the three-month period was fairly
low (6-12 units of survey effort for most grids), and therefore the habitat use
pattern derived from the three-month dataset should be treated with
caution. A more complete picture of
dolphin habitat use pattern should be examined when more survey effort for each
grid is collected throughout the impact phase monitoring programme.
3.5.35 When compared with the habitat use patterns during the baseline
period, dolphin usage in NEL and NWL has drastically diminished in both areas
during the present impact monitoring period (Figure 5 of Appendix J).
During the baseline period, many grids between Siu Mo To and Shum Shui
Kok in NEL recorded moderately high to high dolphin densities, which was in
stark contrast to the complete absence of dolphins there during the present
impact phase period (Figure 5 of
Appendix J).
3.5.36 The density patterns were also drastically different in NWL between
the baseline and impact phase monitoring periods, with high dolphin usage
recorded throughout the area during the baseline period, especially around Sha
Chau, near Black Point, to the west of the airport, as well as between Pillar
Point and airport platform. In
contrast, only several grids with low to moderate dolphin densities were
located at the northwestern and southwestern ends of NWL waters during the
present impact phase period (Figure 5 of Appendix J).
Mother-calf Pairs
3.5.37 During
the present
quarterly period,
no young
calf was sighted at all among the seven groups of dolphins.
Activities and Associations with Fishing Boats
3.5.38 Only one of the seven dolphin groups was engaged in feeding
activity, while no group was engaged in socializing, traveling or
milling/resting activity during the three-month
study period.
3.5.39 The percentage of sightings associated with feeding activity (14.3%)
was comparable to the one recorded during the baseline period (11.6%). However, it should be noted the sample
sizes on total numbers of dolphin sightings were very different between the two
periods.
3.5.40 Distribution of dolphins
engaged in various activities during the present three-month period and baseline period is shown in Figure 6 of Appendix J. The
only dolphin group engaged in feeding activity was sighted near the HKLR09 alignment
at the southwestern corner of NWL waters (Figure
6 of Appendix J). When compared to the baseline period, distribution of
various dolphin activities during the present impact phase monitoring period
was very different with a much more restricted area of occurrence (Figure 6 of Appendix J).
3.5.41 Notably, none of the seven dolphin groups was found to be associated
with any operating fishing vessel during the present impact phase period.
Summary Photo-identification works
3.5.42 From June to August 2018, about 500 digital photographs of Chinese
White Dolphins were taken during the impact phase monitoring surveys for the
photo-identification work.
3.5.43 In total, 13 individuals sighted 16 times altogether were identified
(see summary table in Appendix III of Appendix J and
photographs of identified individuals in Appendix
IV of Appendix J). All of these re-sightings were made in
NWL. Only three individuals (CH34, NL12 and NL145) were re-sighted twice, while
the rest were re-sighted once during the three-month period(Annex III of Appendix J).
3.5.44 Notably, three of these 13 individuals (i.e. CH34, NL202 and NL317)
were also sighted in NWL waters during the HKBCF monitoring surveys under the
same three-month period. Moreover,
seven individuals (i.e. NL145, NL233, NL302, NL317, NL327, NL329 and WL188)
were also sighted in WL waters during the HKLR09 monitoring surveys from June
to August 2018, showing their extensive movements across different survey areas.
Individual range use
3.5.45 Ranging patterns of the 13 individuals identified during the
three-month study period were determined by fixed kernel method, and are shown
in Annex V of Appendix J.
3.5.46 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.
3.5.47 On the other hand, in contrary to previous monitoring quarters, none
of the individuals that consistently utilized WL waters in the past have
extended their range use to NWL waters during the present quarter.
3.5.48 In the upcoming quarters, individual range use and movements should
be continuously monitored to examine whether there has been any consistent
shifts of individual home ranges from North Lantau to West or Southwest Lantau
(and vice versa), as such shift could possibly be related to the HZMB-related
construction works .
Action Level / Limit Level Exceedance
3.5.49
There was one Limit
Level exceedance of dolphin monitoring for the quarterly monitoring data
(between June 2018 ¡V August 2018). According to the contractor¡¦s
information, the marine activities undertaken for HKLR03 during the quarter of
June 2018 ¡V August 2018 included seawall
construction and box culvert construction.
3.5.50 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.
3.5.51 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.
3.5.52 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.
3.5.53 A two-way ANOVA with repeated measures and unequal
sample size was conducted to examine whether there were any significant
differences in the average encounter rates between the baseline and impact
monitoring periods. The two variables that were examined included the two
periods (baseline and impact phases) and two locations (NEL and NWL).
3.5.54 For the comparison between the baseline period and
the present quarter (23rd quarter of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.0022 and 0.0144 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.
3.5.55 For comparison between the baseline period and the
cumulative quarters in impact phase (i.e. first 23 quarters of the impact phase
being assessed), the p-values for the differences in average dolphin encounter
rates of STG and ANI were 0.000000 and 0.000000 respectively. Even if the alpha value is set at
0.00001, significant differences were still detected in both the average
dolphin encounter rates of STG and ANI (i.e. between the two periods and the
locations).
3.5.56 The AFCD monitoring data during June to August 2018
has been reviewed by the dolphin specialist. During the same quarter, no
dolphin was sighted from 88.04 km of survey effort on primary lines in NEL,
while only two groups of two dolphins were sighted from 54.81 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 summer 2018
in NEL and NWL survey area is accurate.
3.5.57
All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Marine Travel Route Plan, the travelling speed of
vessels must not exceed 5 knots when crossing the edge of the proposed marine
park. The Contractor will continue to provide training for skippers to ensure
that their working vessels travel from source to destination to minimize
impacts on Chinese White Dolphin and avoid anchoring at Marine Department¡¦s
designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population
to recover as early as possible.
3.5.58 A meeting was held on 4 September 2018 with
attendance of representative of ENPO, Resident Site Staff (RSS), Environmental
Team (ET) and dolphin specialist for Contract Nos. HY/2013/01, HY/2011/03,
HY/2012/07, HY/2012/08. The discussion/ recommendation as raised in the meeting
which might be relevant to HKLR03 Contract are summarized below.
3.5.59 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.
3.5.60 The dolphin specialists of the projects confirmed that
the CWD sighting around the North of Sha Chau and Lung Kwu Chau Marine Park
(SCLKCMP) has significantly decreased, and it was likely related to the
re-routing of high speed ferry (HSF) from Skypier.
3.5.61 It was reminded that the ETs shall keep reviewing the
implementation status of the dolphin related mitigation measures and remind the
contractor to ensure the relevant measures were fully implemented.
3.5.62 It was recommended that the marine works of HZMB
projects should be completed as soon as possible so as to reduce the overall
duration of impacts and allow the dolphins population to recover as early as
possible.
3.5.63 It was also recommended that the marine works
footprint (e.g., reduce the size of peripheral silt curtain) and vessels for
the marine works should be reduced as much as possible, and vessels idling /
mooring in other part of the North Lantau shall be avoided whenever possible.
3.5.64 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.
3.5.65 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.
3.5.66 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.
3.5.67 There was a discussion on exploring possible further
mitigation measures, for example, controlling the underwater noise. It was
noted that the EIA reports for the projects suggested several mitigation
measures, all of which have been implemented.
3.6
Mudflat Monitoring
Results
Sedimentation Rate
Monitoring
3.6.1 The baseline sedimentation rate monitoring was in September 2012 and
impact sedimentation rate monitoring was undertaken on 15
June 2018. The mudflat surface levels at the four
established monitoring stations and the corresponding XYZ HK1980 GRID
coordinates are presented in Table 3.9 and Table 3.10.
Table 3.9 Measured
Mudflat Surface Level Results
|
Baseline Monitoring
(September 2012)
|
Impact Monitoring
(June 2018)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.165
|
816678.761
|
1.143
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.270
|
815831.565
|
1.006
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.596
|
815953.309
|
1.459
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.379
|
816151.359
|
1.130
|
Table 3.10 Comparison
of Measurement
|
Comparison of measurement
|
Remarks and
Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.005
|
0.034
|
0.193
|
Level
continuously increased
|
S2
|
-0.002
|
0.034
|
0.142
|
Level continuously increased
|
S3
|
0.011
|
0.001
|
0.118
|
Level continuously increased
|
S4
|
-0.054
|
-0.022
|
0.199
|
Level continuously increased
|
3.6.2
This measurement result was generally and relatively higher than the
baseline measurement at S1, S2, S3 and S4.
The mudflat level is continuously increased.
Water Quality
Monitoring
3.6.3
The mudflat monitoring covered water quality
monitoring data. Reference was made to the water quality monitoring data of the
representative water quality monitoring station (i.e. SR3(N)) as in the
EM&A Manual. The water quality
monitoring location (SR3(N)) is shown in Figure 2.1.
3.6.4 Impact water quality
monitoring in San Tau (monitoring station SR3) was conducted in June 2018. The
monitoring parameters included dissolved oxygen (DO), turbidity and suspended
solids (SS).
3.6.5 The
Impact monitoring result for SR3(N) were extracted and summarised in Table 3.11:
Table
3.11 Impact Water Quality Monitoring
Results (Depth Average)
Date
|
Mid Ebb Tide
|
Mid Flood Tide
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
01-Jun-18
|
6.6
|
3.4
|
6.2
|
6.2
|
4.5
|
3.4
|
04-Jun-18
|
6.0
|
2.4
|
5.0
|
6.0
|
1.3
|
4.3
|
06-Jun-18
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
08-Jun-18
|
See Remark 2
|
See Remark 2
|
See Remark 2
|
See Remark 2
|
See Remark 2
|
See Remark 2
|
11-Jun-18
|
6.4
|
3.3
|
4.1
|
6.5
|
3.1
|
5.3
|
13-Jun-18
|
5.3
|
4.1
|
7.5
|
5.3
|
2.8
|
6.4
|
15-Jun-18
|
5.0
|
4.8
|
6.2
|
5.2
|
8.1
|
10.0
|
18-Jun-18
|
5.8
|
7.4
|
5.2
|
5.2
|
5.8
|
5.2
|
20-Jun-18
|
6.0
|
7.4
|
7.1
|
5.8
|
7.1
|
7.5
|
22-Jun-18
|
5.8
|
5.0
|
8.2
|
See Remark 3
|
See Remark 3
|
See Remark 3
|
25-Jun-18
|
5.8
|
4.4
|
5.5
|
5.6
|
9.3
|
14.6
|
27-Jun-18
|
5.8
|
6.6
|
6.1
|
5.9
|
7.5
|
6.9
|
29-Jun-18
|
7.4
|
8.0
|
13.2
|
5.5
|
6.4
|
6.2
|
Average
|
6.0
|
5.1
|
6.8
|
5.7
|
5.6
|
7.0
|
Remarks:
1) Due to adverse weather condition (hoisting Tropical Cyclone
Warning Signal, No. 1, Thunderstorm Warning and Amber Rainstorm Warning Signal),
water quality monitoring for ebb tide and flood tide at station SR3 on 6 June
2018 was cancelled due to safety reasons.
2) Due to adverse weather condition (hoisting of Strong Wind Signal,
No. 3), water quality monitoring for both ebb and flood tides on 8 June 2018
were cancelled due to safety reasons.
3) Thunderstorm Warning and Amber Rainstorm Warning Signal were
issued by Hong Kong Observatory in the afternoon of 22 June 2018. The water
quality monitoring for flood tide on 22 June 2018 was cancelled due to safety
reason.
|
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 June
2018 (totally 5 sampling days between 2nd and 27th June
2018).
Since the field survey of Jun. 2016,
increasing number of trashes and even big trashes (Figure 2.3 of Appendix O) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Wan. Respective measures (e.g. manual clean-up) should be
implemented by responsible government agency units.
Horseshoe Crabs
3.6.7 Active
search method was conducted for horseshoe crab monitoring by two experienced
surveyors in every sampling zone. During the search period, any accessible and
potential area would be investigated for any horseshoe crab individuals within
2-3 hours of low tide period (tidal level below 1.2 m above Chart Datum
(C.D.)). Once a horseshoe crab individual was found, the species was identified
referencing to Li (2008). The prosomal width, inhabiting substratum and
respective GPS coordinate were recorded. A photographic record was taken for
future investigation. Any grouping behavior of
individuals, if found, was recorded. The
horseshoe crab surveys were conducted on 2nd (for TC2), 16th (for
TC1) and 27th (for TC3 and ST) June 2018. The weather was generally
warm and humid on both field days without rainfall.
3.6.8 In Jun. 2017, a big horseshoe
crab was tangled by a trash gill net in ST mudflat (Figure 2.3 of Appendix O). It was released to sea once after photo
recording. The horseshoe crab of such size should be inhabitating sub-tidal
environment while it forages on intertidal shore occasionally during high tide
period. If it is tangled by the trash net for few days, it may die due to
starvation or overheat during low tide period. These trash gill nets are
definitely ¡¥fatal trap¡¦ for the horseshoe crabs and other marine life. Manual
clean-up should be implemented as soon as possible by responsible government
agency units.
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 on 2nd (for TC2), 16th (for TC1) and
27th (for TC3 and ST) June 2018. The
weather was generally hot and sunny on all survey days
Intertidal Soft Shore Communities
3.6.10
The intertidal soft shore community surveys
were conducted in low tide period on 2nd (for TC2),3rd (for TC3), 16th (for TC1) and
17th (for ST) June
2018. In every sampling zone, three 100m horizontal transect lines were laid at
high tidal level (H: 2.0 m above C.D.), mid tidal level (M:1.5 m above C.D.)
and low tidal level (L: 1.0 m above C.D.). Along every horizontal transect
line, ten random quadrats (0.5 m x 0.5 m) were placed.
3.6.11 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 were collected and identified. Finally the top
5 cm surface sediments was dug for visible infauna in the quadrat regardless of
hand core sample was taken.
3.6.12 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), AFCD
(2018).
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 84 ind.) and Tachypleus
tridentatus (total 39 ind.) were recorded. The recorded individuals were
mainly distributed along the shoreline from TC3 to ST. Grouping of 2-10
individuals was usually observed on similar substratum (fine sand or soft mud,
slightly submerged). Photo records were shown in Figure 3.1 of Appendix O
while the complete survey records were listed in Annex II of Appendix
O.
3.6.16 Table 3.1 of Appendix O summarizes the survey results of horseshoe crab in the
present survey. For Carcinoscorpius rotundicauda, 14 individuals were
found in TC1 with average body size 33.10 mm (prosomal width ranged 11.00-55.55
mm) while low search record (3.5 ind. hr-1 person-1)
was resulted. In TC2, there were only 3 individuals with average body size
60.99 mm (47.04-74.44 mm), resulting in very low search record (0.8 ind. hr-1 person-1).
In TC3, there was 27 individuals with average body size 40.54 mm (14.95-67.33
mm). In ST, 40 individuals were found with average body size 41.43 mm
(15.09-70.68 mm). Both TC3 and ST were low-moderate in search record (4.5-6.7
ind. hr-1 person-1) .
3.6.17 Similar survey results were found for Tachypleus
tridentatus. Two individuals were found in TC1 with average body size 48.20
mm (prosomal width ranged 47.29-49.11 mm), resulting in very low search record
(0.5 ind. hr-1 person-1).
In TC3, there were 18 individuals with average body size 60.24 mm (prosomal
width ranged 36.52-82.99 mm). In ST, 19 individuals were found with average body size 57.55 mm (36.04-78.41 mm). Both TC3
and ST were low in search record (3.0-3.2 ind. hr-1 person-1).
No individual was found in TC2.
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. In Jun. 2017, mating pairs of Carcinoscorpius rotundicauda were also
found in TC2 (male 175.27 mm, female 143.51 mm) and TC3 (male 182.08 mm, female
145.63 mm) (Figure 3.2 of Appendix O). In Dec. 2017 and Jun. 2018 (present survey), one mating pair was of Carcinoscorpius rotundicauda was found in TC3 (Dec. 2017: male 127.80 mm, female 144.61 mm; Jun. 2018: male 139 mm, female 149 mm). Figure 3.2 of Appendix O shows the photographic records of all mating pairs found. The recorded mating pairs were
found nearly burrowing in soft mud at low tidal level (0.5-1.0 m above C.D.).
The smaller male was holding the opisthosoma (abdomen carapace) of larger
female from behind. These mating pairs indicated that
breeding of horseshoe crab could be possible along the coast of Tung Chung Wan
rather than ST only, as long as suitable substratum was available. Based on the frequency of encounter, the shoreline between TC3 and
ST should be more suitable mating ground. Moreover suitable breeding period was believed in
wet season (Mar - Sep.) because tiny individuals (i.e. newly hatched) were
usually recorded in Jun. and Sep. every year.
3.6.19 Despite of mating pair, there were occasional records
of large individuals of Carcinoscorpius rotundicauda (prosomal width
ranged 114.45 - 178.67 mm, either single or in pair) and Tachypleus
tridentatus (prosomal width 103 mm) (Figure 3.3 of Appendix O). Based on
their sizes, it indicated that individuals of prosomal width larger than 100 mm
would progress its nursery stage from intertidal habitat to sub-tidal habitat
of Tung Chung Wan. These large individuals might move onto intertidal shore
occasionally during high tide for foraging and breeding. Because they should be
inhabiting sub-tidal habitat most of the time. Their records were excluded from
the data analysis to avoid mixing up with juvenile population living on
intertidal habitat.
3.6.20
No
marked individual of horseshoe crab was recorded in the present survey. Some
marked individuals were found in the previous surveys of Sep. 2013, Mar. 2014
and Sep. 2014. All of them were released through a conservation programme in
charged by Prof. Paul Shin (Department of Biology and Chemistry, The City
University of Hong Kong (CityU)). It was a re-introduction trial of artificial
bred horseshoe crab juvenile at selected sites. So that the horseshoe crab
population might be restored in the natural habitat. Through a personal
conversation with Prof. Shin, about 100 individuals were released in the
sampling zone ST on 20 June 2013. All of them were marked with color tape and
internal chip detected by specific chip sensor. There should be second round of
release between June and September 2014 since new marked individuals were found
in the survey of Sep. 2014.
3.6.21
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
3.6.22 Figures 3.4 and 3.5 of Appendix O show the
changes of number of individuals, mean prosomal width and search record of
horseshoe crabs Carcinoscorpius
rotundicauda and Tachypleus
tridentatus respectively in every sampling zone throughout the monitoring
period.
3.6.23 For TC3 and ST, medium to high search records (i.e.
number of individuals) of both species were always found in wet season (Jun.
and Sep.). The search record of ST was higher from Sep. 2012 to Jun. 2014 while
it was replaced by TC3 from Sep. 2014 to Jun. 2015. The search records were
similar between two sampling zones from Sep. 2015 to Jun. 2016. In Sep. 2016,
the search record of Carcinoscorpius rotundicauda in ST was much higher
than TC3. From Mar. to Jun. 2017, the search records of both species were similar
again between two sampling zones. It showed a natural variation of horseshoe
crab population in these two zones due to weather condition and tidal effect. No obvious
difference of horseshoe crab population was noted between TC3 and ST. In Sep.
2017, the search records of both horseshoe crab species decreased except the Carcinoscorpius
rotundicauda in TC3. The survey results were different from previous
findings that there were usually higher search records in Sep.. One possible
reason was that the serial cyclone hit decreased horseshoe crab activity
(totally 4 cyclone records between Jun. and Sep. 2017, to be discussed in
'Seagrass survey' section). From Dec. 2017 to Jun. 2018 (present survey), the
search records of both species increased again to low-moderate level in TC3 and
ST.
3.6.24 For TC1, the search record was at low to moderate
level throughout the monitoring period. The change of Carcinoscorpius
rotundicauda was relatively more variable than that of Tachypleus
tridentatus. Relatively, the search record was very low in TC2 (2 ind. in
Sep. 2013; 1 ind. In Mar.-Sep. 2014, Mar.-Jun. 2015; 4 ind. in Sep. 2015; 6
ind. in Jun. 2016; 1 ind. in Sep. 2016, 1 ind. from Mar.-Sep. 2017; 3 ind. in
Jun. 2018) .
3.6.25 About the body size, larger individuals of Carcinoscorpius
rotundicauda were usually found in ST and TC1 relative to those in TC3 from
Sep. 2012 to Jun. 2017. But the body size was higher in TC3 and ST followed by
TC1 from Sep. 2017 to Jun. 2018. For Tachypleus tridentatus, larger
individuals were usually found in ST and TC3 followed by TC1 throughout the
monitoring period.
3.6.26 In general, it was obvious that TC3 and ST (western
shore of Tung Chung Wan) was an important nursery ground for horseshoe crab
especially newly hatched individuals due to larger area of suitable substratum
(fine sand or soft mud) and less human disturbance (far from urban district).
Relatively, other sampling zones were not a suitable nursery ground especially
TC2. Possible factors were less area of suitable substratum (especially TC1)
and higher human disturbance (TC1 and TC2: close to urban district and easily
accessible). In TC2, large daily salinity fluctuation was a possible factor
either since it was flushed by two rivers under tidal inundation. The
individuals inhabiting TC1 and TC2 were confined in small foraging area due to
limited area of suitable substrata. Although a mating pair of Carcinoscorpius
rotundicauda was once found in TC2, the hatching rate and survival rate of
newly hatched individuals were believed very low.
Seasonal variation of horseshoe crab population
3.6.27
Throughout the
monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures 3.3 and 3.4 of Appendix O). 4 individuals
of Carcinoscorpius rotundicauda and 12 individuals of Tachypleus
tridentatus were found only. In Dec. 2013, no individual of horseshoe crab
was found. In Dec. 2014, 2 individuals of Carcinoscorpius rotundicauda and
8 individuals of Tachypleus tridentatus were found only. In Dec. 2015, 2
individuals of Carcinoscorpius rotundicauda, 6 individuals of Tachypleus
tridentatus and one newly hatched, unidentified individual were found only.
The horseshoe crabs were inactive and burrowed in the sediments during cold
weather (<15 ºC). Similar
results of low search record in dry season were reported in a previous
territory-wide survey of horseshoe crab. For example, the search records in
Tung Chung Wan were 0.17 ind. hr-1 person-1 and 0.00 ind.
hr-1 person-1 in wet season
and dry season respectively (details see Li, 2008). Relatively the serach
records were much higher in Dec. 2016. There were totally 70 individuals of Carcinoscorpius
rotundicauda and 24 individuals of Tachypleus tridentatus in TC3 and
ST. Because the survey was arranged in early December while the weather was
warm with sunlight (~22 ¢XC during dawn
according to Hong Kong Observatory database, Chek Lap Kokstation on 5 Dec). In
contrast, there was no search record in TC1 and TC2 because the survey was
conducted in mid-December with colder and cloudy weather (~20 ¢XC during dawn on 19 Dec). The horseshoe crab activity
would decrease gradually with the colder climate. In Dec. 2017, the weather was
cold (13-15 ºC during dawn) that very few individuals of both species could be
found as mentioned above.
3.6.28
From Sep. 2012 to Dec. 2013, Carcinoscorpius rotundicauda was a less
common species relative to Tachypleus
tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This
species had ever been believed of very low density in ST hence the encounter
rate was very low. Since Mar. 2014, it was found in all sampling zones with
higher abundance in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and spawning of this species had
occurred about 3 years ago along the coastline of Tung Chung Wan. However,
these individuals were still small while their walking trails were
inconspicuous. Hence there was no search record in previous sampling months.
Since Mar. 2014, more individuals were recorded due to larger size and higher
activity (i.e. more conspicuous walking trail).
3.6.29 For Tachypleus tridentatus, sharp increase
of number of individuals was recorded in ST during the wet season of 2013 (from
Mar. to Sep.). According to a personal conversation with Prof. Shin (CityU),
his monitoring team had recorded similar increase of horseshoe crab population
during wet season. It was believed that the suitable ambient temperature
increased its conspicuousness. However similar pattern was not recorded in the
following wet seasons. The number of individuals increased in Mar. and Jun.
2014 followed by a rapid decline in Sep. 2014. Then the number of individuals
fluctuated slightly in TC3 and ST until Mar. 2017. Apart from natural
mortality, migration from nursery soft shore to subtidal habitat was another
possible cause. Since the mean prosomal width of Tachypleus tridentatus
continued to grow and reached about 50 mm since Mar. 2014. Then it varied
slightly between 35-65 mm from Sep. 2014 to Mar. 2017. Most of the individuals
might have reached a suitable size (e.g. prosomal width 50-60 mm) strong enough
to forage in sub-tidal habitat. In Jun. 2017, the number of individuals
increased sharply again in TC3 and ST. Although mating pair of Tachypleus
tridentatus was not found in previous surveys, there should be new round of
spawning in the wet season of 2016. The individuals might have grown to a more
conspicuous size in 2017 accounting for higher search record. From Sep. 2017 to Jun. 2018 (present survey), moderate numbers of
individual were found in TC3 and ST indicating a stable population size. Lower
population size compared with that in Jun. 2017 was believed the cause of
natural mortality.
3.6.30
Recently, Carcinoscorpius
rotundicauda was a more common horseshoe crab species in Tung Chung Wan. It
was recorded in the four sampling zones while the majority of population
located in TC3 and ST. Due to potential breeding last year, Tachypleus tridentatus became common
again and distributed in TC3 and ST only. Since TC3 and ST were regarded as
important nursery ground for both horseshoe crab species, box plots of prosomal
width of two horseshoe crab species were constructed to investigate the changes
of population in details.
Box plot of horseshoe crab populations in TC3
3.6.31 Figure
3.6 of Appendix O shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the data were
lacking. In Mar 2014, the major size (50% of individual records between upper (top of red box) and lower
quartile (bottom of blue box)) ranged 40-60 mm while only few individuals were
found. From Mar. 2014 to Jun. 2018, the median prosomal width (middle line of
whole box) and major size (whole box) decreased after Mar. of every year. It
was due to more small individuals found. It indicated new rounds of
spawning. Also there were slight increasing trends of body size from Jun. to
Mar. of next year since 2015. It indicated a stable growth of individuals.
Focused on larger juveniles (upper whisker), the size range was quite variable
(prosmal width 60-90 mm) along the sampling months. Juveniles reaching this
size might gradually migrate to sub-tidal habitats.
3.6.32 For Tachypleus
tridentatus, the major size ranged 20-50 mm while the number of individuals
fluctuated from Sep. 2012 to Jun. 2014. Then a slight but consistent growing
trend was observed from Sep. 2014 to Jun. 2015. The prosomal width increased
from 25-35 mm to 35-65 mm. As mentioned, the large individuals might have reached a suitable size for migrating from the
nursery soft shore to subtidal habitat. It accounted for the declined
population in TC3. From Mar. to Sep. 2016, slight increasing trend of major
size was noticed again. From Dec. 2016 to Jun. 2017, similar increasing trend
of major size was noted with much higher number of individuals. It reflected
new round of spawning. In Sep. 2017, the major size decreased while the trend
was different from previous two years. Such decline might be the cause of
serial cyclone hit between Jun. and Sep. 2017 (to be discussed in the 'Seagrass
survey' section). From Dec. 2017 to Jun. 2018 (present survey), increasing
trend was noted again. Across the whole monitoring period, the larger juveniles (upper whisker)
usually reached 60-80 mm in prosomal width, even 90 mm occasionally. Juveniles
reaching this size might gradually migrate to sub-tidal habitats.
Box
plot of horseshoe crab populations in ST
3.6.33 Figure
3.7 of Appendix O shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. From Mar. 2014 to Sep. 2017, the size of major population
decreased and more small individuals (i.e. lower whisker) were recorded after
Jun. of every year. It indicated new round of spawning. Also there were similar
increasing trends of body size from Sep. to Jun. of next year between 2014 and
2017. It indicated a stable growth of individuals. Across the whole monitoring
period, the larger juveniles (i.e. upper whisker) usually ranged 60-80 mm in
prosomal width except one individual (prosomal width 107.04 mm) found in Mar.
2017. It reflected juveniles reaching this size would gradually migrate to
sub-tidal habitats.
3.6.34 For Tachypleus tridentatus, a consistent growing trend was observed for
the major population from Dec. 2012 to Dec. 2014 regardless of change of search
record. The prosomal width increased from 15-30 mm to 60-70 mm. As mentioned,
the large juveniles might have reached a suitable
size for migrating from the nursery soft shore to subtidal habitat. From Mar.
to Sep. 2015, the size of major population decreased slightly to a prosomal
width 40-60 mm. At the same time, the number of individuals decreased
gradually. It further indicated some of large juveniles might have migrated to
sub-tidal habitat, leaving the smaller individuals on shore. There was an
overall growth trend. In Dec. 2015, two big individuals (prosomal width 89.27
mm and 98.89 mm) were recorded only while it could not represent the major
population. In Mar. 2016, the number of individual was very few in ST that no
boxplot could be produced. In Jun. 2016, the prosomal width of major population
ranged 50-70 mm. But it dropped clearly to 30-40 mm in Sep. 2016 followed by an
increase to 40-50 mm in Dec. 2016, 40-70 mm in Mar. 2017 and 50-60mm in Jun.
2017. Based on overall higher number of small individuals from Jun. 2016 to
Sep. 2017, it indicated new round of spawning. From Sep. 2017 to Jun. 2018
(present survey), the major size range increased slightly from 40-50 mm to
45-60 mm indicating a continuous growth. Throughout the monitoring period, the
larger juveniles ranged 60-80 mm in prosomal width. Juveniles reaching this
size would gradually migrate to sub-tidal habitats.
3.6.35 As a summary for horseshoe crab
populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014 to 2018 while the spawning
time should be in spring. There were consistent, increasing
trends of population size in these two sampling zones. For Tachypleus tridentatus, small individuals were rarely found in both zones from 2014 to 2015. It was believed
no occurrence of successful spawning. The existing individuals (that recorded
since 2012) grew to a mature size and migrated to sub-tidal habitat. Hence the
number of individuals decreased gradually. From 2016
to 2018, new round of spawning was recorded in ST while increasing number of
individuals and body size was noticed.
Impact of the HKLR
project
3.6.36 It was
the 23rd survey of the EM&A programme during the construction
period. Based on the results, impact of the HKLR project could not be detected
on horseshoe crabs. The population change was mainly determined by seasonal
variation while new rounds of spawning were observed for both species. In case,
abnormal phenomenon (e.g. very few numbers of horseshoe crab individuals in wet
season, large number of dead individuals on the shore) is found, it would be
reported as soon as possible.
Seagrass Beds
3.6.37 Since the commencement of the EM&A monitoring
programme, two species of seagrass Halophila ovalis and Zostera
japonica were recorded in TC3 and ST (Figure 3.8 of Appendix O). In
general, Halophila ovalis was occasionally found in TC3 in few, small to
medium patches. But it was commonly found in ST in medium to large seagrass
bed. Moreover, it had grown extensively and covered significant mudflat area at
0.5-2.0 m above C.D. between TC3 and ST. Another seagrass species Zostera
japonica was found in ST only. It was relatively lower in vegetation area
and was co-existing with Halophila ovalis nearby the mangrove strand at
2.0 m above C.D.
3.6.38 Table 3.2 of Appendix O summarizes the results of seagrass beds survey. In TC3, one
very small patch of Halophila ovalis was found in soft mud area at 2.0 m
above C.D. while the total seagrass bed area and vegetation coverage were about
0.3 m2 and ~20% respectively. In ST, three small-medium sized
patches of Halophila ovalis were found while the total seagrass bed area
was about 1072.0 m2. The largest patch
was a horizontal strand with area ~990 m2 and highly variable vegetation coverage 20-100%, located
nearby seaward size of mangrove plantation at 2.0 m above C.D. At vicinity,
there was a medium, horizontal strand (~80 m2, coverage 20-100%) and a very small patch (~2 m2, coverage 40%) at 2.0 m above C.D. Another seagrass species
Zostera japonica was not found in present survey. Annex III of Appendix O shows the complete record of seagrass
survey.
3.6.39 According to the previous results, majority
of seagrass bed was confined in ST, the temporal change of both seagrass
species was
investigated in details:
Temporal variation of seagrass beds
3.6.40 Figure
3.10 of Appendix O shows the changes of estimated total
area of seagrass beds in ST along the sampling months. For Zostera japonica,
it was not recorded in the 1st and 2nd surveys of
monitoring programme. Seasonal recruitment of few, small patches (total
seagrass area: 10 m2) was found in
Mar. 2013 that grew within the large patch of seagrass Halophila ovalis.
Then the patch size increased and merged gradually with the warmer climate from
Mar. to Jun. 2013 (15 m2). However, the
patch size decreased and remained similar from Sep. 2013 (4 m2) to
Mar. 2014 (3 m2). In Jun. 2014, the patch size increased obviously
again (41 m2) with warmer climate followed by a decrease between
Sep. 2014 (2 m2) and Dec. 2014 (5 m2). From Mar. to Jun.
2015, the patch size increased sharply again (90 m2). It might be
due to the disappearance of the originally dominant seagrass Halophila
ovalis resulting in less competition for substratum and nutrients. From
Sep. 2015 to Jun. 2016, it was found coexisting with seagrass Halophila
ovalis with steady increasing patch size (from 44 m2 to 115 m2)
and variable coverage. In Sep. 2016, the patch size decreased again to (38 m2)
followed by an increase to a horizontal strand (105.4 m2) in Jun.
2017. And it was no longer co-exisitng with Halophila ovalis. Between
Sep. 2014 and Jun. 2017, an increasing trend was noticed from Sep. to Jun. of
next year followed by a rapid decline in Sep. of next year. It was possibly the
causes of heat stress, typhoon and stronger grazing pressure during wet season.
From Sep. 2017 to Jun. 2018 (present survey), no seagrass patch of Zostera
japonica was found .
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
large patch at low tidal level (786 m2). Typhoon or strong water
current was a possible cause (Fong, 1998). In Sep. 2014, there were two
tropical cyclone records in Hong Kong (7th-8th Sep.: no
cyclone name, maximum signal number 1; 14th-17th Sep.: Kalmaegi,
maximum signal number 8SE) before the seagrass survey dated 21st Sep. 2014. The
strong water current caused by the cyclone, Kalmaegi especially, might have
given damage to the seagrass beds. In addition, natural heat stress and grazing
force were other possible causes reducing seagrass beds area. Besides, very
small patches of Halophila ovalis could be found in other mud flat area
in addition to the recorded patches. But it was hardly distinguished due to
very low coverage (10-20%) and small leaves.
3.6.42 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
unfavourable 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 unfavouable condition. Previous studies reported that Halophila
ovalis had little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999).
Hence the seagrass bed of this species was susceptible to temporary light
deprivation events such as flooding river runoff (Longstaff and Dennison,
1999).
3.6.45
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 unfavourable
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 Jun. 2017. From
Mar. to Jun. 2015, 2-3 small patches of Halophila ovalis were newly
found coinhabiting with another seagrass species Zostera japonica. But
its total patch area was still very low relative to the previous records. The
recolonization rate was low while cold weather and insufficient sunlight were
possible factors between Dec. 2014 and Mar. 2015. Moreover, it would need to
compete with seagrass Zostera japonica for substratum and nutrient.
Since Zostera japonica had extended and had covered the original
seagrass bed of Halophila ovalis at certain degree. From Jun. 2015 to
Mar. 2016, the total seagrass area of Halophila ovalis had increased
rapidly from 6.8 m2 to 230.63 m2.
It had recolonized its original patch locations and covered Zostera japonica.
In Jun. 2016, the total seagrass area increased sharply to 4707.3 m2.
Similar to the previous records of Mar to Jun. 2014, the original patch area
increased further to a horizontally long strand. Another large seagrass beds
colonized the lower tidal zone (1.0-1.5 m above C.D.). In Sep. 2016, this patch
extended much and covered significant soft mud area of ST, resulting in sharp
increase of total area (24245 m2). It indicated the second extensive
colonization of this r-strategy seagrass. In Dec. 2016, this extensive
seagrass patch decreased in size and had separated into few, undistinguishable
patches. Moreover, the horizontal strand nearby the mangrove vegetation
decreased in size (Figure 3.10 of
Appendix O). The total seagrass bed decreased to 12550 m2. From
Mar. to Jun. 2017, the seagrass bed area remained generally stable
(12438-17046.5 m2) but the vegetation coverage fluctuated (20-50% in
Mar. 2017 to 80-100% in Jun. 2017).
Re-disappearance of
seagrass bed
3.6.48 In Sep 2017, the whole seagrass bed of Halophila ovalis disappeared again along the shore of TC3 and ST (Figure 3.11 of Appendix O). It was similar to the case between Sep. and Dec. 2014. As
mentioned, strong water current (e.g. cyclone) or deteriorated water quality
(e.g. high turbidity) were the possible causes.
3.6.49 Between the survey periods of Jun. and Sep. 2017, there were four
tropical cyclone records in Hong Kong (Merbok in 12-13th, Jun.; Roke
in 23rd, Jul.; Hato in 22-23rd, Aug.; Pakhar in 26-27th,
Aug.) (online database of Hong Kong Observatory). All of them reaches signal 8
or above especially Hato (highest signal 10).
3.6.50 According to the water quality monitoring results (Jul. to Aug.
2017) of the two closest monitoring stations SR3 and I5 of the respective
EM&A programme, the overall water quality was in normal fluctuation. There
was one exceedance of suspended solids (SS) at SR3 on 12 Jul. 2017. The SS
concentration reached 24.7 mg/L during mid-ebb tide. It exceeded the Action
Level (≤23.5 mg/L) but was far below the Limit Level (≤34.4 mg/L). Since such exceedance was slight and temporary, its
effect to seagrass bed should be minimal.
3.6.51 Overall, the disappearance of seagrass beds in ST was believed the
cause of serial cyclone hit in Jul and Aug. 2017. Based on previous findings,
the seagrass beds of both species were expected to recolonize the mudflat as
long as the vicinal water quality was normal. The whole recolonization process
(from few, small patches to extensive strand) would be gradual lasting 1.5 to 2
years. From Dec. 2017 to Mar. 2018, there was still no recolonization of few,
small patches of seagrass at the usual location. It was different from previous
re-colonization (Mar. 2015 - Jun. 2017) Until Jun. 2018 (present survey), new,
small seagrass patches were found at the usual location (seaward side of
mangrove plantation at 2.0 m C.D.) again (Figure
3.11 of Appendix O). It showed the recolonization of seagrass bed while it
was expected to grow to an extensive seagrass bed in 1.5-2 years.
Impact of the HKLR project
3.6.52 It was
the 23rd survey of the EM&A programme during the construction
period. Throughout the monitoring period, the disappearance of seagrass beds was
believed the cause of cyclone hits rather than impact of HKLR project. In
present survey, new seagrass beds were found showing gradual recolonization of
seagrass.
Intertidal Soft
Shore Communities
3.6.53 Table 3.3 and Figure 3.12 of Appendix O show the types of substratum along the horizontal transect at every
tidal level in all sampling zones. The relative distribution of different
substrata was estimated by categorizing the substratum types (Gravels &
Boulders / Sands / Soft mud) of the ten random quadrats along the horizontal
transect. The distribution of substratum types varied among tidal levels and
sampling zones:
¡P
In TC1, high
percentages of ¡¥Gravels and Boulders¡¦ (80-100%) were recorded at all tidal
levels. Low distribution of ¡¥Sands¡¦ (20%) was recorded at high and low tidal
levels .
¡P
In TC2, high
percentage of ¡¥Sands¡¦ (70%) was recorded at high tidal level followed by
¡¥Gravels and Boulders¡¦ (20%). At mid tidal level, there was even distribution of
¡¥Sands¡¦ (50%) and ¡¥Soft mud¡¦ (40%). At low tidal level, the major substratum
type was 'Soft mud' (70%) followed by ¡¥Sands¡¦ (30%).
¡P
In TC3, high
percentages of ¡¥Sands¡¦ (70-100%) were recorded at high and mid tidal levels.
Low percentage of ¡¥Soft mud¡¦ (30%) was recorded at high tidal level. At low
tidal level, the major substratum type was ¡¥Gravels and Boulders¡¦ (80%) .
¡P
In ST, ¡¥Gravels
and Boulders¡¦ was the main substratum (100%) at high tidal level. At mid tidal
level, there was high percentage of ¡¥Gravels and Boulders¡¦ (80%) followed by
'Sands' (20%). At low tidal level, the main substratum was 'Sands' (100%) .
3.6.54 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.
3.6.55 Table 3.4 of Appendix O lists the total
abundance, density and number of taxon of every phylum in this survey. A total
of 15814 individuals were recorded. Mollusca was clearly the most abundant
phylum (total abundance 15275 ind., density 509 ind. m-2, relative
abundance 96.6 %). The second and third abundant phya were Arthropoda (388
ind., 13 ind. m-2, 2.5 %) and Annelida (78 ind., 3 ind. m-2,
0.5 %) respectively. Relatively other phyla were very low in abundances
(density £1 ind. m+, relative
abundance £0.2 %).
Moreover, the most diverse phylum was Mollusca (37 taxa) followed by Arthropoda
(14 taxa) and Annelida (8 taxa). There was 1 taxon recorded only for other
phyla.
3.6.56 The taxonomic resolution and complete list of recorded fauna are shown in Annexes IV and V of Appendix O respectively. According to the latest
identification key of potamidid snails in Hong Kong mangroves published by
Agriculture, Fisheries and Conservation Department (details see AFCD, 2018),
the names of following gastropod species were revised:
¡P
Cerithidea cingulata was revised
as Pirenella asiatica
¡P
Cerithidea djadjariensis was
revised as Pirenella incisa
¡P
Cerithidea rhizophorarum was
revised as Cerithidea moerchii
3.6.57 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 (2913-5756 ind.) varied among the four sampling zones while the phyla
distributions were similar. In general, Mollusca was the most dominant phylum
(no. of individuals: 2838-5613 ind; relative abundance 92.6-98.0%; density
378-748 ind. m-2). Other phyla
were much lower in number of individuals. Arthropoda (48-197 ind.; 1.5-6.0 %;
6-26 ind. m-2) was the second abundant phylum. Annelida (30-32 ind.;
0.5-1.0 %; 4 ind. m-2) was the third abundant phylum in TC2 and TC3.
Sipuncula was common but in low abundance in TC1, TC2 and TC3 (7-13 ind.;
0.2-0.3 %; 1-2 ind. m-2). Similarly, Cnidaria (sea anemone) was
common in ST (11 ind.; 0.4%; 1 ind. m-2). Relatively other phyla
were very low in abundance in all sampling zones.
Dominant species in
every sampling zone
3.6.58
Table 3.6 of Appendix O lists the abundant species (relative abundance >10 %) in every sampling zone. In the present survey, most of
the listed abundant species were of low to moderate densities (50-250 ind. m-2).
Few listed species of high or very high density (> 250 ind. m-2)
were regarded as dominant species. Other listed species of lower density (<
50 ind. m-2) were regared as common species.
3.6.59
In TC1, the
substratum was mainly ¡¥Gravels and Boulders¡¦ at all tidal levels. It was
dominated by gastropod Batillaria multiformis (264 ind. m-2,
relative abundance 55 %) at high density followed by gastropod Pirenella
incisa (115 ind. m-2, 24 %) at low-moderate density. At mid
tidal level, there were few gastropods Batillaria multiformis (180 ind.
m-2, 33 %), Monodonta
labio (106 ind. m-2, 19 %), Pirenella incisa (70 ind. m-2,
13 %) at low-moderate densities. And the rock oyster Saccostrea cucullata (119
ind. m-2, 22 %, attached on boulders) was also abundant. At low
tidal level, rock oyster Saccostrea cucullata (158 ind. m-2,
30 %) was abundant with other abundant gastropods Monodonta labio (111
ind. m-2, 21 %) and Pirenella incisa (57 ind. m-2,
11 %) .
3.6.60
In TC2, the
substratum was mainly 'Sands' at high tidal level. Gastropod Pirenella
incisa was clearly dominant at high density (301 ind. m-2, 54
%). At mid tidal level (main substratum types 'Sands' and 'Soft mud'),
gastropods Pirenella incisa (124 ind. m-2, 25 %), Batillaria
zonalis (89 ind. m-2, 18 %) and rock oyster Saccostrea
cucullata (122 ind. m-2, 24 %, attached on boulders) were
abundant at low-moderate densities. At low tidal level (main substratum type
¡¥Soft mud¡¦), rock oyster Saccostrea cucullata was abundant at
low-moderate density (72 ind. m-2, 29 %) followed by common
gastropods Pirenella incisa (41 ind. m-2, 16 %), Batillaria
zonalis (41 ind. m-2, 16 %) and
barnacle Balanus amphitrite (31 ind. m-2, 12 %, attached on
boulders).
3.6.61 In TC3, the major substratum types were mainly ¡¥Sands¡¦
at high and mid tidal levels. Gastropod Pirenella incisa (369-383 ind. m-2, 42-56 %) was
dominant followed by other abundant gastropods Batillaria multiformis (136-158
ind. m-2, 18-20 %) and Pirenella asiatica (120-223 ind. m-2,
18-26 %). At low tidal level (major substratum: ¡¥Gravels and Boulders¡¦), rock
oyster Saccostrea cucullata (301 ind. m-2, 40 %,
attached on boulders) was dominant at high density followed by gastropod Monodonta
labio (180 ind. m-2, 24 %) .
3.6.62 In ST, the major substratum types were mainly ¡¥Gravels
and Boulders¡¦ at high and mid tidal levels. At high tidal level, gastropods Monodonta
labio (163 ind. m-2, 31 %), Batillaria multiformis (102
ind. m-2, 20 %), rock oyster Saccostrea cucullata (73 ind. m-2,
14 %, attached on boulders) and limpet Cellana toreuma (62 ind. m-2,
12 %) were abundant at low-moderate densities. At mid tidal level, rock oyster Saccostrea
cucullata (174 ind. m-2, 33%) and Monodonta labio (88
ind. m-2, 17 %) were abundant at low-moderate densities followed by
common gastropod Pirenella incisa (50 ind. m-2, 10 %). At low
tidal level (major substratum type: ¡¥Sands¡¦), there were three common species
including gastropods Pirenella incisa (31 ind. m-2, 25 %), Batillaria
zonalis (16 ind. m-2, 13 %) and rock oyster Saccostrea
cucullata (26 ind. m-2, 21%) .
3.6.63 In general, there was no consistent zonation pattern
of species distribution across all sampling zones and tidal levels. The species
distribution should be determined by the type of substratum primarily. In
general, gastropods Pirenella incisa (total number of individuals: 3953
ind., relative abundance 25.0 %), Batillaria multiformis (2516 ind.,
15.9 %), Pirenella asiatica (1333 ind., 8.4 %) and Batillaria zonalis
(670 ind., 4.2 %) were the most commonly occurring species on sandy and
soft mud substrata. Rock oyster Saccostrea cucullata (2830 ind., 17.9
%), gastropod Monodonta labio (1888 ind., 11.9 %) and limpet Cellana
toreuma (391 ind., 2.5 %) were the commonly occurring species inhabiting
gravel and boulders substratum.
Biodiversity and
abundance of soft shore communities
3.6.64 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 .
3.6.65 Among the sampling zones, there was no obvious
difference of mean species number regardless of tidal levels. The mean species
numbers ranged 10-11 spp. 0.25 m-2 among all
sampling zones. The mean density of TC3 (767 ind. m-2) were higher
than TC1 (517 ind. m-2) followed by TC2 and ST (388-436 ind. m-2).
The higher mean density of TC3 was mainly accounted by one dominant gastropod
at high and mid tidal levels. Such dominance resulted in lower H¡¦ (1.3)
in TC3 compared to other sampling zones (1.5-1.6). The J was similar
(0.6-0.7) among all sampling zones.
3.6.66 Across the tidal levels, there were slightly
increasing trends of mean species number and density from high to low tidal
level in TC1 and TC3 but vice versa in TC2 and ST. For the mean H¡¦,
there were generally increasing trends from high to low tidal level in TC1, TC2
and TC3. But there was no consistent difference of J observed across the
tidal levels. In general, the spatial differences of these biological
parameters were highly related to substratum types.
3.6.67 Figures 3.13 to 3.16 of Appendix O show the temporal changes of mean species number, mean
density, H¡¦ and J at every tidal level and in every sampling zone
along the sampling months. In general, all the biological parameters fluctuated
seasonally throughout the monitoring period. Lower mean species number and
density were recorded in dry season (Dec.) but the mean H' and J fluctuated
within a stable range.
3.6.68 From Jun. to Dec. 2017, there were steady decreasing
trends of mean species number and density in TC2, TC3 and ST regardless of
tidal levels. It might be an unfavourable change reflecting environmental
stresses. The heat stress and serial cyclone hit were believed the causes
during the wet season of 2017. From Mar. to Jun. 2018 (present survey),
increases of mean species number and density were observed in all sampling
zones. It indicated the recovery of intertidal community.
Impact of the HKLR project
3.6.69 It was
the 23rd survey of the EM&A programme during the construction
period. Based on the results, impacts of the HKLR project were not detected on
intertidal soft shore community. In case of other abnormal phenomena (e.g.
rapid or consistent decline of fauna densities and species number) are
observed, it would be reported as soon as possible.
3.7
Solid and
Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical Waste
Producer on 12 July 2012 for the Contract. Sufficient numbers of receptacles
were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental
Licenses and Permits
3.8.1
The valid environmental licenses and permits during
the reporting period are summarized in Appendix L.
4
Environmental Complaint and
Non-compliance
4.1.1
The detailed air quality, noise, water quality and dolphin exceedances
are provided in Appendix M. Also, the summaries of
the environmental exceedances are presented as follows:
Air Quality
4.1.2
No Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5
and AMS6 during the reporting period. No Action and Limit Level exceedances of
24-hr TSP were recorded at AMS5. One Limit Level exceedance of 24-hr TSP was
recorded at AMS6 during the reporting period.
Noise
4.1.3 An Action Level exceedance was recorded as a complaint
was received during reporting period. No Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
4.1.4 No Action and Limit Level
exceedances of turbidity level and no Action Level exceedances of suspended
solids level were recorded during reporting period. 13 Action Level exceedances
and 5 Limit Level of dissolved oxygen level were recorded during the reporting
period. 2 Action Level exceedances of suspended solids level were recorded
during the reporting period.
Dolphin
4.1.5 There was one Limit Level exceedances of dolphin monitoring for the
quarterly monitoring data (between June 2018 ¡V August 2018). According to the
contractor¡¦s information, the marine activities undertaken for HKLR03 during
the quarter of June 2018 ¡V August 2018 included seawall construction and box culvert construction.
4.1.6 There is no evidence showing the current LL
non-compliance directly related to the construction works of HKLR03 (where the
amounts of working vessels for HKLR03 have been decreasing), although the
generally increased amount of vessel traffic in NEL during the impact phase has
been partly contributed by HKLR03 works since October 2012. It should also be
noted that reclamation work under HKLR03 (adjoining the Airport Island)
situates in waters which has rarely been used by dolphins in the past, and the
working vessels under HKLR03 have been travelling from source to destination in
accordance with the Marine Travel Route to minimize impacts on Chinese White
Dolphin (CWD). In addition, the contractor will implement proactive mitigation
measures such as avoiding anchoring at Marine Department¡¦s designated anchorage
site ¡V Sham Shui Kok Anchorage (near Brothers Island) as far as practicable.
4.1.7 All
dolphin protective measures are fully and properly implemented in accordance
with the EM&A Manual. According to the Marine Travel Route Plan, the
travelling speed of vessels must not exceed 5 knots when crossing the edge of
the proposed marine park. The Contractor will continue to provide training for
skippers to ensure that their working vessels travel from source to destination
to minimize impacts on Chinese White Dolphin and avoid anchoring at Marine Department¡¦s
designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as
far as practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
4.2
Summary of Environmental Complaint, Notification of Summons and
Successful Prosecution
4.2.1 During the reporting period, a complaint
(Complaint No. COM-2018-142) in relation to the environmental impacts (Noise
impact) was received on 29 June 2018. A further complaint related to same issue
was received on 6 July 2018. A summary of environmental complaint for June 2018
and July 2018 is presented in Table
4.1.
Table 4.1 A
Summary of Environmental Complaint for the Reporting Period
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaint
|
Complaint No COM-2018-142
|
EPD (ENPO referred
the email to SOR, Contractor and ET on 29 June 2018 and 6 July 2018)
|
Noise
|
4.2.2 According to the Contractor¡¦s
information, while the Contractor commenced the excavation for the landscaping
works at areas along the original coastline and outside Cathay Dragon House / Dragonair
& CNAC (Group) Building, they encountered a zone of extremely
hard bedrock layer. The Contractor had
to undertake the breaking of such bedrock layer.
¡P
A hydraulic breaker
with smaller capacity had been used in order to reduce noise generated from the
rock breaking operation.
¡P
The breaking tip of
hydraulic breaker used for rock breaking operation had been wrapped by muffler.
¡P
The rock breaking
works outside the Cathay Dragon House/ Dragonair & CNAC (Group) Building
had moved immediately further away to the north-eastern
corner of the Building.
4.2.4
As confirmed by Contractor, breaking of any hard substances including rock/stone,
concrete etc. will not be carried out after 9 July 2018
at work area outside the Cathay Dragon House/ Dragonair & CNAC (Group)
Building). ET conducted a site inspection on
10 July 2018 (around 13:15 hours), rock breaking works were not observed next
to Cathay Dragon
House/ Dragonair & CNAC (Group) Building.
4.2.5 Based on our
investigation result, the complaint was related to Contract No. HY/2011/03. The Contractor has implemented Environmental
Mitigation Implementation Schedule as per the EM&A Manual, such as cover
the breaker tip with muffler; minimize the quantities
of noisy plant as far as practicable. Although the
rock breaking works outside
the Cathay Dragon House/ Dragonair & CNAC (Group) Building were completed on 9 July 2018, the Contractor has been
continuously reminded to properly implement Environmental Mitigation Measures
as per the EM&A Manual to minimize the potential
noise nuisance caused to the public/ surrounding.
4.2.6 The
details of cumulative statistics of Environmental Complaints are provided in Appendix N.
4.2.7 No notification of summons and prosecution was received during the
reporting period. Statistics on notifications of summons and successful
prosecutions are summarized in Appendix M.
5
Comments, Recommendations and Conclusion
5.1.1
According to the environmental
site inspections undertaken during the reporting period, the following
recommendations were provided:
¡P The Contractor was reminded to provide drip tray
for the chemical containers at S9 and N4 and N13A.
¡P The Contractor was reminded provide a lid for
the water-filled barrier at N13A.
¡P The Contractor was reminded to spray water for
breaking activities at S7.
¡P The Contractor was reminded to spray water
during excavation to avoid dust emission at S15.
¡P The Contractor was reminded to clear the
stagnant water within the drip tray at S9.
¡P The Contractor was reminded to clear the
stagnant water inside the steel beam at S9.
¡P The Contractor was reminded to clear the
stagnant water inside the container at N1.
¡P The Contractor was reminded to clear the sand
/mud inside the u-channel at N1.
¡P The Contractor was reminded to remove sand and mud near
site entrance/exit from N1.
¡P The Contractor was reminded to remove the waste
fuel filing station of S9.
¡P The Contractor was reminded to remove the waste
at N1, HMA and S9, S15 and N4a and PR10.
¡P The Contractor was reminded to remove the stagnant
water inside the drip tray at S15.
¡P The Contractor was reminded to remove stagnant
water in the hole of water-filled barrier at N4a.
¡P The Contractor was reminded to remove the
stagnant water at PR10 and N13A.
¡P The Contractor was reminded to remove the waste
on the ground at N4.
¡P The Contractor was reminded to remove the
general refuse on the ground at S15.
¡P The Contractor was reminded to remove the
general refuse on the ground from HMA.
¡P The Contractor was reminded to remove
construction waste on the ground at PR10.
¡P The Contractor was reminded to remove the
construction waste on the ground from S15.
¡P The Contractor was reminded to remove the waste
from S7, S23 and N4.
¡P The Contractor was reminded to remove the unused
gas containers from S15.
¡P The Contractor was reminded to remove the
concrete deposit at N13A.
¡P The Contractor was reminded to dispose of the
unused chemical drum as chemical waste at S15.
¡P The Contractor was reminded to maintain the silt
curtains properly at Portion X.
5.2.1
The impact monitoring programme for air quality, noise, water quality
and dolphin ensured that any deterioration in
environmental condition was readily detected and timely actions taken to
rectify any non-compliance. Assessment and analysis of monitoring results
collected demonstrated the environmental impacts of the contract. With
implementation of the recommended environmental mitigation measures, the
contract¡¦s environmental impacts were considered environmentally acceptable.
The weekly environmental site inspections ensured that all the environmental
mitigation measures recommended were effectively implemented.
5.2.2
The
recommended environmental mitigation measures, as included in the EM&A
programme, effectively minimize the potential environmental impacts from the
contract. Also, the EM&A programme effectively monitored the environmental
impacts from the construction activities and ensure the proper implementation
of mitigation measures. No particular recommendation was advised for the
improvement of the programme.
5.3.1 The construction phase and EM&A programme of the Contract
commenced on 17 October 2012. This is the
twenty-fourth Quarterly EM&A Report which summarizes the monitoring results and audit findings of the EM&A
programme during the reporting period from 1 June 2018 to 31 August 2018.
Air Quality
5.3.2
No Action and Limit Level exceedances of 1-hr TSP were recorded at AMS5
and AMS6 during the reporting period. No Action and Limit Level exceedances of
24-hr TSP were recorded at AMS5. One Limit Level exceedance of 24-hr TSP was
recorded at AMS6 during the reporting period.
Noise
5.3.3 An Action Level exceedance was recorded as a complaint
was received during reporting period. No Limit Level exceedances for noise
were recorded during daytime on normal weekdays of the reporting period.
Water Quality
Dolphin
5.3.5
There was one Limit Level exceedance of dolphin monitoring for the
quarterly monitoring data between June 2018 ¡V August 2018.
5.3.6
During the present quarter of
dolphin monitoring, no adverse impact from the activities of this construction
project on Chinese White Dolphins was noticeable from general observations.
5.3.7
Although dolphins rarely occurred in the area of
HKLR03 construction in the past and during the baseline monitoring period, it
is apparent that dolphin usage has been dramatically reduced in NEL since 2012,
and many individuals have shifted away completely from the important habitat
around the Brothers Islands.
5.3.8
It is critical to continuously monitor the
dolphin usage in North Lantau region in the upcoming quarters, to determine
whether the dolphins are continuously affected by the various construction
activities in relation to the HZMB-related works, and whether suitable
mitigation measure can be applied to revert the situation.
Mudflat - Sedimentation Rate
5.3.9 This measurement result was
generally and relatively higher than the baseline measurement at S1, S2, S3 and
S4. The mudflat level is continuously increased.
Mudflat - Ecology
Environmental Site Inspection and Audit
5.3.11 Environmental site inspection was carried out on 6, 13, 20 and
29 June 2018; 4, 11, 18 and 27 July 2018; and 1, 8, 15, 22 and 31 August 2018 . Recommendations on remedial
actions were given to the Contractors for the deficiencies identified during
the site inspections.
5.3.12 A complaint
(Complaint No. COM-2018-142) in relation to the environmental impacts (Noise
impact) was received on 29 June 2018. A further complaint related to same issue
was received on 6 July 2018. Based on our investigation result, the complaint
was related to Contract No. HY/2011/03.
5.3.13 No notification of summons and prosecution was received during the
reporting period.