Contract No. HY/2011/03
Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road
Section between Scenic
Hill and Hong Kong Boundary Crossing Facilities
Quarterly EM&A Report
No. 27 (March 2019 to May 2019)
18 September 2019
Revision 1
Main Contractor Designer
Executive Summary
The
Hong Kong-Zhuhai-Macao Bridge (HZMB) Hong Kong Link Road (HKLR) serves to
connect the HZMB Main Bridge at the Hong Kong Special Administrative Region
(HKSAR) Boundary and the HZMB Hong Kong Boundary Crossing Facilities (HKBCF)
located at the north eastern waters of the Hong Kong International Airport
(HKIA).
The
HKLR project has been separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and
Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract)
and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China
State Construction Engineering (Hong Kong) Ltd. was awarded by Highways
Department as the Contractor to undertake the construction works of Contract
No. HY/2011/03. The main works of the Contract include land tunnel at Scenic
Hill, tunnel underneath Airport Road and Airport Express Line, reclamation and
tunnel to the east coast of the Airport Island, at-grade road connecting to the
HKBCF and highway works of the HKBCF within the Airport Island and in the
vicinity of the HKLR reclamation.
The Contract is part of the HKLR Project and HKBCF Project, these
projects are considered to be ¡§Designated Projects¡¨,
under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap
499) and EIA Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were
prepared for the Project. The
current Environmental Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/K for
HKBCF were issued on 22 December 2014 and 11 April 2016, respectively. These
documents are available through the EIA Ordinance Register. The construction
phase of Contract was commenced
on 17 October 2012.
BMT 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-seventh Quarterly EM&A report for the Contract which summarizes
the monitoring results and audit findings of the EM&A programme during the
reporting period from 1 March 2019 to 31 May 2019.
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
|
Mar 2019
|
Apr 2019
|
May 2019
|
Air
Quality
|
1-hr
TSP
|
4, 8, 14, 20, 26 and 29
|
3, 9, 12, 18, 24 and 30
|
6, 10, 16, 22 and 28
|
24-hr
TSP
|
1, 7, 13, 19, 25 and 28
|
2, 8, 11, 17, 23 and 29
|
AMS5: 3, 9, 15, 21, 27
and 31
AMS6: 3, 9, 15, 24, 27 and 31
|
Noise
|
4, 14, 20 and 26
|
3, 9, 15, 24 and 30
|
6, 16, 22 and 28
|
Water Quality
|
1, 4, 6, 8, 11, 13, 15, 18, 20, 22, 25, 27 and 29
|
1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26 and 29
|
1, 3, 6, 8, 10, 13, 15, 17, 20, 22,24,29 and 31
|
Chinese
White Dolphin
|
4, 11, 13 and 18
|
10, 15, 23 and 25
|
2, 7, 21 and 23
|
Mudflat Monitoring (Ecology)
|
21 and 22
|
-
|
-
|
Mudflat Monitoring (Sedimentation rate)
|
21
|
-
|
-
|
Site Inspection
|
1, 6, 13, 20 and 29
|
3, 10, 17 and 26
|
3, 8, 15, 22 and 31
|
Due to boat unavailability, the dolphin monitoring was scheduled from 9,
11 and 17 April 2019 to 10, 15 and 25 April 2019 respectively.
Thunderstorm Warning was issued by the Hong Kong Observatory on 27 May
2019, the water quality monitoring for flood tide was cancelled due to safety
reason.
The
monitoring time for TSP monitoring on 21 May 2019 at AMS6 (Dragonair
building) was less than 24-hr due to motor failure. The 24-hr TSP monitoring
was rescheduled from 21 May 2019 to 24 May 2019.
Breaches of Action and Limit Levels
A
summary of environmental exceedances for this reporting period is as follows:
Environmental Monitoring
|
Parameters
|
Action Level (AL)
|
Limit Level (LL)
|
Air Quality
|
1-hr
TSP
|
0
|
0
|
24-hr
TSP
|
0
|
0
|
Noise
|
Leq (30 min)
|
0
|
0
|
Water Quality
|
Suspended
solids level (SS)
|
3
|
0
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin Monitoring
|
Quarterly
Analysis (Mar 2019 to May 2019)
|
0
|
1
|
All
investigation reports for exceedances of the Contract have been submitted to
ENPO/IEC for comments and/or follow up to identify whether the exceedances
occurred related to other HZMB contracts.
Implementation of Mitigation Measures
Site
inspections were carried out on a weekly basis to monitor the implementation of
proper environmental pollution control and mitigation measures for the Project.
Potential environmental impacts due to the construction activities were
monitored and reviewed.
Complaint Log
There
were two complaints received in relation to the environmental impacts during
this reporting period.
A
summary of environmental complaints for this reporting period is as follows:
Environmental Complaint No.
|
Date
of Complaint Received
|
Description
of Environmental Complaint
|
N/A
|
EPD (ENPO referred the
email from EPD to HyD, SOR, Contractor and ET) on
3 April 2019
|
Dust
|
COM-2019-163
|
SOR referred the email
from HyD to Contractor, ET and IEC/ENPO on 30
April 2019
|
Waste
|
Notifications of Summons
and Prosecutions
There
were no notifications of summons or prosecutions received during this reporting
period.
Reporting Changes
This
report has been developed in compliance with the reporting requirements for the
subsequent EM&A reports as required by the Updated EM&A Manual for HKLR
(Version 1.0).
The
proposal for the change of Action Level and Limit Level for suspended solid and
turbidity was approved by EPD on 25 March 2013.
The
revised Event and Action Plan for dolphin monitoring was
approved by
EPD on 6 May 2013.
The
original monitoring station at IS(Mf)9 (Coordinate:
813273E, 818850N) was observed inside the perimeter silt curtain of Contract
HY/2010/02 on 1 July 2013, as such the original impact water quality monitoring
location at IS(Mf)9 was temporarily shifted outside
the silt curtain. As advised by the
Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted
to facilitate safe anchorage zone of construction barges/vessels until end of
2013 subject to construction progress.
Therefore, water quality monitoring station IS(Mf)9
was shifted to 813226E and 818708N since 1 July 2013. According to the water quality
monitoring team¡¦s observation on 24 March 2014, the original monitoring
location of IS(Mf)9 was no longer enclosed by the
perimeter silt curtain of Contract HY/2010/02. Thus, the impact water quality
monitoring works at the original monitoring location of IS(Mf)9
has been resumed since 24 March 2014.
Transect
lines 1, 2, 7, 8, 9 and 11 for dolphin monitoring have been revised due to the
obstruction of the permanent structures associated with the construction works
of HKLR and the southern viaduct of TM-CLKL, as well as provision of adequate
buffer distance from the Airport Restricted Areas. The EPD issued a memo and confirmed that
they had no objection on the revised transect lines on 19 August 2015.
The
water quality monitoring stations at IS10 (Coordinate: 812577E, 820670N) and
SR5 (811489E, 820455N) are located inside Hong Kong International Airport
(HKIA) Approach Restricted Areas. The previously granted Vessel's Entry Permit
for accessing stations IS10 and SR5 were expired on 31 December 2016. During
the permit renewing process, the water quality monitoring location was shifted
to IS10(N) (Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E,
820978N) on 2, 4 and 6 January 2017 temporarily. The permit has been granted by
Marine Department on 6 January 2017. Thus, the impact water quality monitoring
works at original monitoring location of IS10 and SR5 has been resumed since 9
January 2017.
Transect
lines 2, 3, 4, 5, 6 and 7 for dolphin monitoring have been revised and transect
line 24 has been added due to the presence of a work zone to the north of the
airport platform with intense construction activities in association with the
construction of the third runway expansion for the Hong Kong International
Airport. The EPD issued a memo and confirmed that they had no objection on the
revised transect lines on 28 July 2017. The alternative dolphin transect lines
are adopted starting from August¡¦s dolphin monitoring.
A
new water quality monitoring team has been employed for carrying out water
quality monitoring work for the Contract starting from 23 August 2017. Due to
marine work of the Expansion of Hong Kong International Airport into a Three-Runway
System (3RS Project), original locations of water quality monitoring stations
CS2, SR5 and IS10 are enclosed by works boundary of 3RS Project. Alternative
impact water quality monitoring stations, naming as CS2(A), SR5(N) and IS10(N)
was approved on 28 July 2017 and were adopted starting from 23 August 2017 to
replace the original locations of water quality monitoring for the Contract.
The
role and responsibilities as the ET Leader of the Contract was temporarily
taken up by Mr Willie Wong instead of Ms Claudine Lee from 25 September 2017 to
31 December 2017.
The
topographical condition of the water monitoring stations SR3 (Coordinate:
810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A (Coordinate:
823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot be accessed
safely for undertaking water quality monitoring. The water quality monitoring
has been temporarily conducted at alternative stations, namely SR3(N) (Coordinate 810689E, 816591N), SR4(N) (Coordinate:
814705E, 817859N) and SR10A(N) (Coordinate: 823644E, 823484N) since 1 September
2017. The water quality monitoring at station SR10B was temporarily conducted
at Coordinate: 823683E, 823187N on 1, 4, 6, 8 September 2017 and has been
temporarily fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E,
823159N) since 11 September 2017. Proposal for permanently relocating the aforementioned stations was approved by EPD on 8 January
2018.
The works area WA5
was handed over to other party on 22 June 2013.
According to latest
information received in July 2018, the works area WA7 was handed over to other
party on 28 February 2018 instead of 31 January 2018.
1.1.2
The HKLR project has been
separated into two contracts. They are Contract
No. HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section
between Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter
referred to as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao
Bridge Hong Kong Link Road-Section between HKSAR Boundary and Scenic Hill.
1.1.3
China State Construction Engineering
(Hong Kong) Ltd. was awarded by Highways Department (HyD)
as the Contractor to undertake the construction works of Contract No.
HY/2011/03. The Contract is part of the HKLR
Project and HKBCF Project, these projects are considered to
be ¡§Designated Projects¡¨, under Schedule 2 of the Environmental Impact
Assessment (EIA) Ordinance (Cap 499) and EIA Reports (Register No.
AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project. The current Environmental Permit (EP) EP-352/2009/D
for HKLR and EP-353/2009/K for HKBCF were issued on 22 December 2014 and 11
April 2016, respectively. These documents are available through the EIA
Ordinance Register. The construction phase of Contract was commenced on 17 October 2012. The works area WA7 was handed
over to other party on 31 January 2018. Figure 1.1 shows
the project site boundary.
1.1.4
BMT Hong Kong Limited has been appointed by the Contractor to implement
the EM&A programme for the Contract in accordance
with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and will be
providing environmental team services to the Contract. Ramboll Hong Kong Limited was employed
by HyD as the Independent Environmental Checker (IEC)
and Environmental Project Office (ENPO) for the Project. The
project organization with regard to the environmental
works is provided in Appendix A.
1.1.5
This is the twenty-seventh Quarterly Environmental Monitoring and Audit (EM&A) report for the
Contract which summarizes the monitoring results and audit findings of the
EM&A programme during the reporting period from 1
March 2019 to 31 May 2019.
1.2.1 The project organization structure and lines of
communication with respect to the on-site environmental management structure
with the key personnel contact names and numbers are shown in Appendix A.
1.3
Construction Programme
1.3.1 A
copy of the Contractor¡¦s construction programme is
provided in Appendix B.
1.4
Construction
Works Undertaken During the Reporting Period
1.4.1 A
summary of the construction activities undertaken during this reporting period
is shown in Table
1.1. The Works
areas of the Contract are showed in Appendix C[KE2] .
Table 1.1 Construction
Activities during Reporting Period
Description of Activities
|
Site Area
|
Dismantling/trimming of temporary 40mm
stone platform for construction of seawall
|
Portion X
|
Construction of seawall
|
Portion X
|
Loading and unloading of filling materials
|
Portion X
|
Works
for diversion
|
Airport Road
|
Establishment
of site access
|
Airport Road/ Airport Express Line/ East Coast Road
|
Finishing works for Highway Operation and
Maintenance Area Building
|
Portion X
|
Finishing works for Scenic Hill Tunnel
West Portal Ventilation building
|
West Portal
|
Landscaping
works
|
Portion X
|
2.1
Summary of EM&A Requirements
2.1.1
The EM&A programme requires environmental
monitoring of air quality, noise, water quality, dolphin monitoring and mudflat
monitoring as specified in the approved EM&A Manual.
2.1.2 A summary of Impact
EM&A requirements is presented in Table
2.1. The
locations of air quality, noise and water quality monitoring stations are shown
as in Figure
2.1. The transect line layout in Northwest and Northeast Lantau Survey
Areas is presented in Figure 2.2.
Table 2.1 Summary
of Impact EM&A Requirements
Environmental
Monitoring
|
Description
|
Monitoring
Station
|
Frequencies
|
Remarks
|
Air Quality
|
1-hr TSP
|
AMS 5 & AMS
6
|
At least 3 times every 6 days
|
While the
highest dust impact was expected.
|
24-hr TSP
|
At least once every 6 days
|
--
|
Noise
|
Leq (30mins),
L10 (30mins) and
L90 (30mins)
|
NMS 5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡P Depth
¡P Temperature
¡P Salinity
¡P Dissolved
Oxygen (DO)
¡P Suspended
Solids (SS)
¡P DO
Saturation
¡P Turbidity
¡P pH
|
¡P Impact
Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9
& IS10(N),
¡P Control/Far
Field Stations:
CS2(A) & CS(Mf)5,
¡P Sensitive
Receiver Stations:
SR3(N), SR4(N), SR5(N), SR10A(N) & SR10B(N2)
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 1.75 hour of the predicted time)
|
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth be less than 3
m, only the mid-depth station will be monitored).
|
Dolphin
|
Line-transect Methods
|
Northeast Lantau survey
area and Northwest Lantau survey area
|
Twice
per month
|
--
|
Mudflat
|
Horseshoe crabs, seagrass beds, intertidal soft shore communities,
sedimentation rates and water quality
|
San Tau and Tung Chung Bay
|
Once every 3 months
|
--
|
2.2.1
Table 2.2 presents the Action
and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.
Table 2.2 Action and
Limit Levels for 1-hour TSP, 24-hour
TSP and Noise
Environmental Monitoring
|
Parameters
|
Monitoring Station
|
Action Level
|
Limit Level
|
Air Quality
|
1-hr
TSP
|
AMS
5
|
352 µg/m3
|
500 µg/m3
|
AMS
6
|
360 µg/m3
|
24-hr
TSP
|
AMS
5
|
164 µg/m3
|
260 µg/m3
|
AMS
6
|
173 µg/m3
|
Noise
|
Leq (30 min)
|
NMS 5
|
When
one documented complaint is received
|
75
dB(A)
|
2.2.2 The Action and Limit Levels for water quality monitoring are given as in
Table 2.3.
Table 2.3 Action
and Limit Levels for Water Quality
Parameter
(unit)
|
Water Depth
|
Action
Level
|
Limit Level
|
Dissolved Oxygen (mg/L)
|
Surface and Middle
|
5.0
|
4.2 except 5 for Fish
Culture Zone
|
Bottom
|
4.7
|
3.6
|
Turbidity (NTU)
|
Depth average
|
27.5 or 120% of upstream
control station¡¦s turbidity at the same tide of the same day;
The action level has been
amended to ¡§27.5 and 120% of upstream control station¡¦s turbidity at the same
tide of the same day¡¨ since 25 March 2013.
|
47.0 or 130% of turbidity
at the upstream control station at the same tide of same day;
The limit level has been
amended to ¡§47.0 and 130% of turbidity at the upstream control station at the
same tide of same day¡¨ since 25 March 2013.
|
Suspended Solid (SS)
(mg/L)
|
Depth average
|
23.5 or 120% of upstream
control station¡¦s SS at the same tide of the same day;
The action level has been
amended to ¡§23.5 and 120% of upstream control station¡¦s SS at the same tide of
the same day¡¨ since 25 March 2013.
|
34.4 or 130% of SS at the
upstream control station at the same tide of same day and 10mg/L for Water
Services Department Seawater Intakes;
The limit level has been
amended to ¡§34.4 and 130% of SS at the upstream control station at the same
tide of same day and 10mg/L for Water Services Department Seawater Intakes¡¨
since 25 March 2013
|
Notes:
(1) Depth-averaged
is calculated by taking the arithmetic means of reading of all three depths.
(2) For DO,
non-compliance of the water quality limit occurs when monitoring result is
lower that the limit.
(3) For SS &
turbidity non-compliance of the water quality limits occur when monitoring
result is higher than the limits.
(4) The change to
the Action and limit Levels for Water Quality Monitoring for the EM&A works
was approved by EPD on 25 March 2013. Therefore, the amended Action and Limit
Levels are applied for the water monitoring results obtained on and after 25
March 2013.
2.2.3
The Action and Limit Levels
for dolphin monitoring are shown in Tables
2.4 and 2.5.
Table 2.4 Action
and Limit Level for Dolphin Impact Monitoring
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
Limit Level
|
STG < 40% of baseline
&
ANI < 40% of baseline
|
Remarks:
(1)
STG means quarterly average encounter rate of
number of dolphin sightings.
(2)
ANI means quarterly average encounter rate of
total number of dolphins.
(3)
For North Lantau Social Cluster, AL will be
triggered if either NEL or NWL fall below the criteria; LL will be triggered if
both NEL and NWL fall below the criteria.
Table 2.5 Derived
Value of Action Level (AL) and Limit Level (LL)
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 4.2 & ANI
< 15.5
|
STG < 6.9 & ANI
< 31.3
|
Limit Level
|
(STG < 2.4 & ANI
< 8.9) and (STG < 3.9 & ANI < 17.9)
|
Remarks:
(1)
STG means quarterly average encounter rate of
number of dolphin sightings.
(2)
ANI means quarterly average encounter rate of
total number of dolphins.
(3)
For North Lantau Social Cluster, AL will be
triggered if either NEL or NWL fall below the criteria; LL will be triggered if
both NEL and NWL fall below the criteria.
2.3.1 The Event Actions Plans for air quality, noise, water quality and
dolphin monitoring are annexed in Appendix D.
2.4.1 Environmental mitigation measures for the
contract were recommended in the approved EIA Report. Appendix E lists the recommended mitigation measures and the implementation
status.
3
Environmental Monitoring and Audit
3.1
Implementation of Environmental Measures
3.1.1
In response to the site audit findings, the Contractor
have rectified all observations identified in environmental site inspections undertaken
during the reporting period. Details of site audit findings and the corrective
actions during the reporting period are presented in Appendix F.
3.1.2
A summary of the Implementation Schedule of
Environmental Mitigation Measures (EMIS) is presented in Appendix E.
3.1.3
Regular marine travel route for
marine vessels were implemented properly in accordance to the submitted plan
and relevant records were kept properly.
3.1.4
Dolphin Watching Plan was
implemented during the reporting period. No dolphins inside the silt curtain were observed. The relevant
records were kept properly.
3.2.1
The monitoring results for 1-hour TSP and 24-hour TSP
are summarized in Tables 3.1 and 3.2 respectively.
Detailed impact air quality monitoring results and relevant graphical
plots are presented in Appendix G.
Table 3.1 Summary
of 1-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
Mar 2019
|
AMS5
|
61
|
40 ¡V 118
|
352
|
500
|
AMS6
|
70
|
37 ¡V 241
|
360
|
Apr 2019
|
AMS5
|
40
|
32 ¡V 49
|
352
|
AMS6
|
39
|
34 ¡V 51
|
360
|
May 2019
|
AMS5
|
55
|
28 ¡V 113
|
352
|
AMS6
|
42
|
33 ¡V 50
|
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)
|
Mar 2019
|
AMS5
|
54
|
17 ¡V 79
|
164
|
260
|
AMS6
|
57
|
19 ¡V 93
|
173
|
Apr 2019
|
AMS5
|
36
|
28 ¡V 48
|
164
|
AMS6
|
32
|
21 ¡V 42
|
173
|
May 2019
|
AMS5
|
38
|
18 ¡V 69
|
164
|
AMS6
|
38
|
17 ¡V 65
|
173
|
3.2.2
No Action and Limit Level exceedances
of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6 during the reporting period.
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)
|
Mar 2019
|
NMS5
|
59
|
57 ¡V 60
|
When one documented complaint is received
|
75
|
Apr 2019
|
59
|
56 ¡V 66
|
May 2019
|
58
|
56 ¡V 60
|
3.3.2 No Action/Limit Level exceedances for noise were recorded during
daytime on normal weekdays of the reporting period.
3.3.3
Major noise sources during the noise monitoring included
construction activities of the Contract and nearby traffic noise and insect
noise.
3.4.1 Impact water quality
monitoring was conducted at all designated monitoring stations during the reporting
period. Impact water quality monitoring results and relevant graphical plots
are provided in Appendix I.
3.4.2 No Action and Limit Level exceedances of turbidity level and dissolved
oxygen were recorded during reporting period. No Limit Level exceedance of suspended solids were recorded during the
reporting period.
3.4.3 3 Action Level exceedances of suspended solids level were recorded during
the reporting period. The exceedances of suspended solids level recorded during
reporting period was considered to be attributed to
other external factors such as sea condition, rather than the contract works. The
exceedances were considered as non-contract related. Record of ¡§Notification of
Environmental Quality Limit Exceedances¡¨ is provided in Appendix M.
3.4.4
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 (ArcViewý 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 ArcViewý
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(updated)
3.5.9 During the period of March to May 2019, 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 794.91 km of survey effort was
collected, with 96.2% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or
below with good visibility). Among
the two areas, 293.34 km and 501.57 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 572.37 km,
while the effort on secondary lines was 222.54 km.
Survey effort conducted on both primary and secondary lines were considered to be 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 March and May 2019, only five groups of 11 Chinese White
Dolphins were sighted, with the summary table of
dolphin sightings shown in Annex II of Appendix J. All five dolphin sightings were made during on-effort
search, with four of them being made on primary lines.
3.5.13 In addition, all dolphin groups were sighted in
NWL, and no dolphin was sighted at all in NEL. In fact, since August 2014, only two
sightings of two lone dolphins were made in NEL during HKLR03 monitoring
surveys.
Distribution
3.5.14 Distribution of dolphin
sightings made during HKLR03 monitoring surveys conducted from March to May 2019 is shown in Figure 1 of Appendix J. These
sightings were all scattered at the western portion of the North Lantau region,
with no particular concentration (Figure 1 of Appendix J).
3.5.15 As consistently recorded in previous monitoring quarters, the
dolphins were completely absent from the central and eastern portions of North
Lantau waters (Figure 1 of Appendix J).
Moreover, all dolphin sightings were located far away from the HKLR03
and HKBCF reclamation sites as well as along the alignment of Tuen Mun-Chek Lap Kok Link (TMCLKL) (Figure
1 of Appendix
J).
However,
one group of two dolphins was sighted near the HKLR09 alignment to the west of
Shum Wat.
3.5.16 Sighting distribution of dolphins during the present impact phase
monitoring period (March-May 2019) 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
occurrences 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 24 quarters of HKLR03 monitoring, which has resulted in zero to extremely
low dolphin encounter rates in this area.
3.5.17 In NWL survey area, dolphin occurrence was also drastically
different between the baseline and impact phase periods. During the present impact monitoring
period, dolphins were sighted infrequently there, and their distribution was
restricted to the western portion of the North Lantau region, which was in
stark contrast to their frequent occurrences throughout the area during the
baseline period (Figure 1 of Appendix J).
3.5.18 Another comparison in dolphin distribution was made between the six
quarterly periods of spring months in 2014-19. Among the six spring periods,
dolphins were regularly sighted in NWL waters in 2014, but such usage was
dramatically reduced to very low levels in the five subsequent spring periods
of 2015-19 (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
1.04 sightings and 2.28 dolphins per 100 km of survey effort respectively,
while the encounter rates of sightings (STG) and dolphins (ANI) in NEL were
both nil for this quarter.
Table 3.4 Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) During Reporting Period
(March ¡V
May 2019)
Survey Area
|
Dolphin
Monitoring
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
Primary Lines Only
|
Primary Lines Only
|
Northeast Lantau
|
Set 1 (4 & 11 Mar 2019)
|
0.00
|
0.00
|
Set 2 (13 & 18 Mar 2019)
|
0.00
|
0.00
|
Set 3 (10 & 15 Apr 2019)
|
0.00
|
0.00
|
Set 4 (23 & 25 Apr 2019)
|
0.00
|
0.00
|
Set 5 (2
& 7 May
2019)
|
0.00
|
0.00
|
Set 6 (21 & 23 May 2019)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (4 & 11 Mar 2019)
|
0.00
|
0.00
|
Set 2 (13 & 18 Mar 2019)
|
3.41
|
6.81
|
Set 3 (10 & 15 Apr 2019)
|
0.00
|
0.00
|
Set 4 (23 & 25 Apr 2019)
|
1.64
|
3.27
|
Set 5 (2
& 7 May
2019)
|
1.71
|
5.13
|
Set 6 (21 & 23 May 2019)
|
0.00
|
0.00
|
Table 3.5 Comparison of average dolphin encounter rates from impact
monitoring period (March ¡V May 2019) 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
|
1.13 ¡Ó
1.39
|
9.85 ¡Ó 5.85
|
2.54 ¡Ó 3.00
|
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 24
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 August 2014, with only two lone dolphins sighted there on two
separate occasions despite consistent and intensive survey effort being
conducted in this survey area.
Table 3.6 Comparison of Average Dolphin Encounter Rates in Northeast Lantau
Survey Area from All Quarters of Impact Monitoring Period and Baseline
Monitoring Period (Sep ¡V Nov 2011)
Monitoring Period
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
September-November
2011 (Baseline)
|
6.00 ¡Ó 5.05
|
22.19 ¡Ó 26.81
|
December 2012-February 2013 (Impact)
|
3.14 ¡Ó 3.21
|
6.33 ¡Ó 8.64
|
March-May 2013 (Impact)
|
0.42 ¡Ó 1.03*
|
0.42 ¡Ó 1.03*
|
June-August 2013 (Impact)
|
0.88 ¡Ó 1.36
|
3.91 ¡Ó 8.36
|
September-November
2013 (Impact)
|
1.01 ¡Ó 1.59
|
3.77 ¡Ó 6.49
|
December
2013-February 2014 (Impact)
|
0.45 ¡Ó 1.10
|
1.34 ¡Ó 3.29
|
March-May 2014 (Impact)
|
0.00*
|
0.00*
|
June-August 2014 (Impact)
|
0.42 ¡Ó 1.04
|
1.69 ¡Ó 4.15
|
September-November 2014 (Impact)
|
0.00
|
0.00
|
December 2014-February 2015 (Impact)
|
0.00
|
0.00
|
March-May 2015 (Impact)
|
0.00*
|
0.00*
|
June-August 2015 (Impact)
|
0.44 ¡Ó 1.08
|
0.44 ¡Ó 1.08
|
September-November 2015 (Impact)
|
0.00
|
0.00
|
December 2015-February 2016 (Impact)
|
0.00
|
0.00
|
March-May 2016 (Impact)
|
0.00*
|
0.00*
|
June-August 2016 (Impact)
|
0.00
|
0.00
|
September-November 2016 (Impact)
|
0.00
|
0.00
|
December
2016-February 2017 (Impact)
|
0.00
|
0.00
|
March-May 2017 (Impact)
|
0.00*
|
0.00*
|
June-August 2017 (Impact)
|
0.00
|
0.00
|
September-November 2017 (Impact)
|
0.00
|
0.00
|
December
2017-February 2018 (Impact)
|
0.00
|
0.00
|
March-May 2018 (Impact)
|
0.00*
|
0.00*
|
June-August 2018 (Impact)
|
0.00
|
0.00
|
September-November 2018 (Impact)
|
0.00
|
0.00
|
December
2018-February 2019 (Impact)
|
0.00
|
0.00
|
March-May 2019 (Impact)
|
0.00*
|
0.00*
|
Notes:
1) The encounter rates deduced from the baseline monitoring period have
been recalculated based only on survey effort and on-effort sighting data made
along the primary transect lines under favourable conditions.
2) ¡Ó denotes the standard deviation of the average
encounter rates.
3) The encounter rates in spring months were in blue and marked with asterisk.
3.5.22 On the other hand, the average
dolphin encounter rates (STG and ANI) in NWL during the present impact phase
monitoring period (reductions of 88.5% and 94.3%
respectively) were only tiny fractions of the ones recorded during the
three-month baseline period, indicating a dramatic decline in dolphin usage of
this survey area as well during the present impact phase period (Table 3.7).
Table 3.7 Comparison
of Average Dolphin Encounter Rates in Northwest Lantau Survey Area from All
Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep ¡V Nov
2011)
Monitoring Period
|
Encounter rate (STG) (no. of on-effort dolphin sightings per
100 km of survey effort)
|
Encounter rate (ANI) (no. of dolphins from all on-effort
sightings per 100 km of survey effort)
|
September-November 2011 (Baseline)
|
9.85 ¡Ó 5.85
|
44.66 ¡Ó 29.85
|
December 2012-February 2013 (Impact)
|
8.36 ¡Ó 5.03
|
35.90 ¡Ó 23.10
|
March-May 2013 (Impact)
|
7.75 ¡Ó 3.96*
|
24.23 ¡Ó 18.05*
|
June-August 2013 (Impact)
|
6.56 ¡Ó 3.68
|
27.00 ¡Ó 18.71
|
September-November
2013 (Impact)
|
8.04 ¡Ó 1.10
|
32.48 ¡Ó 26.51
|
December
2013-February 2014 (Impact)
|
8.21 ¡Ó 2.21
|
32.58 ¡Ó 11.21
|
March-May 2014 (Impact)
|
6.51 ¡Ó 3.34*
|
19.14 ¡Ó 7.19*
|
June-August 2014 (Impact)
|
4.74 ¡Ó 3.84
|
17.52 ¡Ó 15.12
|
September-November 2014 (Impact)
|
5.10 ¡Ó 4.40
|
20.52 ¡Ó 15.10
|
December 2014-February 2015 (Impact)
|
2.91 ¡Ó 2.69
|
11.27 ¡Ó 15.19
|
March-May 2015 (Impact)
|
0.47 ¡Ó 0.73*
|
2.36 ¡Ó 4.07*
|
June-August 2015 (Impact)
|
2.53 ¡Ó 3.20
|
9.21 ¡Ó 11.57
|
September-November 2015 (Impact)
|
3.94 ¡Ó 1.57
|
21.05 ¡Ó 17.19
|
December 2015-February 2016 (Impact)
|
2.64 ¡Ó 1.52
|
10.98 ¡Ó 3.81
|
March-May 2016 (Impact)
|
0.98 ¡Ó 1.10*
|
4.78 ¡Ó 6.85*
|
June-August 2016 (Impact)
|
1.72 ¡Ó 2.17
|
7.48 ¡Ó 10.98
|
September-November 2016 (Impact)
|
2.86 ¡Ó 1.98
|
10.89 ¡Ó 10.98
|
December 2016-February 2017 (Impact)
|
3.80 ¡Ó 3.79
|
14.52 ¡Ó 17.21
|
March-May 2017 (Impact)
|
0.93 ¡Ó 1.03*
|
5.25 ¡Ó 9.53*
|
June-August 2017 (Impact)
|
2.20 ¡Ó 2.88
|
6.58 ¡Ó 8.12
|
September-November 2017 (Impact)
|
3.12 ¡Ó 1.91
|
10.35 ¡Ó 9.66
|
December 2017-February 2018 (Impact)
|
4.75 ¡Ó 2.26
|
15.73 ¡Ó 15.94
|
March-May 2018 (Impact)
|
2.88 ¡Ó 4.81*
|
11.12 ¡Ó 22.46*
|
|
June-August 2018 (Impact)
|
1.16 ¡Ó 1.39
|
2.87 ¡Ó 3.32
|
|
September-November 2018 (Impact)
|
1.51 ¡Ó 2.25
|
2.70 ¡Ó 3.78
|
|
December 2018-February 2019 (Impact)
|
2.40 ¡Ó 1.88
|
7.95 ¡Ó 6.60
|
|
March-May 2019 (Impact)
|
1.13 ¡Ó 1.39*
|
2.54 ¡Ó 3.00*
|
|
Notes:
1) The encounter rates deduced from the baseline monitoring period have
been recalculated based only on survey effort and on-effort sighting data made
along the primary transect lines under favourable conditions.
2) ¡Ó denotes the standard
deviation of the average encounter rates.
3) The
encounter rates in spring months were in blue and marked with asterisk.
3.5.23 Notably, when comparing the seven quarterly periods in spring months
since 2014, the quarterly encounter rates in the spring of 2019 were consistent
with the very low levels as recorded in the spring periods of 2015-17, despite
a slight rebound in spring of 2018 (Table
3.7). The dramatic drop in dolphin occurrence in NWL in recent years should
raise serious concerns, and such temporal trend should be closely monitored in
the upcoming monitoring quarters as the construction activities of HZMB works
will soon be completed 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 (26th quarter of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.0019 and 0.0113 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 26 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 five years throughout the HZMB construction.
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 has been no sign of recovery of dolphin usage, even though almost all
marine works associated with the HZMB construction have been completed, and the
Brothers Marine Park has been established in late 2016 as a compensation
measure for the permanent habitat loss in association with the HKBCF
reclamation works.
Group Size
3.5.29 Group size of Chinese White Dolphins ranged from two to three
individuals per group in North Lantau region during March to May 2019. The
average dolphin group sizes from these three months were compared with the ones
deduced from the baseline period in September to November 2011, as shown in Table 3.8.
Table
3.8 Comparison
of Average Dolphin Group Sizes between Reporting Period (Mar
¡V May 2019) and Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average Dolphin Group Size
|
Reporting Period
|
Baseline Monitoring Period
|
Overall
|
2.20 ¡Ó 0.45 (n = 5)
|
3.72 ¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
2.20 ¡Ó 0.45 (n = 5)
|
3.92 ¡Ó 3.40 (n = 49)
|
Note:
1) ¡Ó denotes the standard deviation of the average
group size.
3.5.30 The average dolphin group size in NWL waters during March to May
2019 was much lower than the one recorded during the three-month baseline
period, but it should be noted that the sample size of only five dolphin groups
in the present quarter was a tiny fraction of the sample size of 66 dolphin
groups sighted during the baseline period (Table
3.8).
3.5.31 Notably, all five groups were very small with 2-3 individuals per
group only (Annex II of Appendix J).
Habitat
Use
3.5.32 From March to May 2019, only
five grids in North Lantau waters recorded dolphin occurrences. The only grid with moderate dolphin
density was located to the northeast of Lung Kwu Chau(Figures 4a and 4b of Appendix J). In contrast, the rest of the grids only recorded moderately low DPSE values.
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 one grid with moderate dolphin density was located in the
western portion of North Lantau 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 five groups of dolphins.
Activities and Associations with Fishing Boats
3.5.38 None of the five dolphin groups was engaged in feeding, socializing,
traveling or milling/resting activity during the three-month
study period.
3.5.39 Moreover, none of the groups was found to be associated with any
operating fishing vessel during the present impact phase period
Summary Photo-identification works
3.5.40 From March to May 2019, roughly 400 digital photographs of Chinese
White Dolphins were taken during the impact phase monitoring surveys for the
photo-identification work.
3.5.41 In total, five individuals sighted six 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. With the exception of
NL123 being re-sighted twice, the other four individuals (i.e. NL182, NL202,
NL261 and WL145) were all re-sighted only once during the three-month
monitoring period (Annex
III of Appendix J).
3.5.42 Notably, none of these individuals was sighted in WL waters during
the HKLR09 monitoring surveys from the same three-month period of March to May
2019.
Individual range use
3.5.43 Ranging patterns of the five individuals identified during the
three-month study period were determined by fixed kernel method,
and are shown in Annex V of Appendix J.
3.5.44 With the exception of WL145, the other four identified dolphins sighted
in the present quarter were mostly utilizing NWL waters as in the past, and
they 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.
3.5.45 On the other hand, in contrary to previous monitoring quarters, none
of the five individuals have extended their range use to WL waters during the
spring quarter of 2019, while one individual (WL145) that consistently utilized
WL waters in the past have extended its range use to NWL survey area during the
present quarter.
Action Level / Limit Level Exceedance
3.5.46 There was a Limit Level exceedance of dolphin
monitoring for the quarterly monitoring data (between March
2019 to May 2019). According to the contractor¡¦s information, the marine
activities undertaken for HKLR03 during the quarter of March 2019 ¡V May 2019
included seawall construction and box culvert construction.
3.5.47 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 work area 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.
3.5.48 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.
3.5.49 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.
3.5.50 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).
3.5.51 For the comparison between the baseline period and
the present quarter (26th quarter of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.0019 and 0.0113 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.
3.5.52 For comparison between the baseline period and the
cumulative quarters in impact phase (i.e. first 26 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).
3.5.53 The AFCD monitoring data during March to May 2019
has been reviewed by the dolphin specialist. During the same quarter, no
dolphin was sighted from 145.50 km of survey effort on primary lines in NEL,
while only one group of one dolphin was sighted from 200.64 km of survey effort
on primary lines in NWL. This review has confirmed that the rare occurrence of
dolphins reported by the HKLR03 monitoring surveys in spring 2019 in NEL and
NWL survey area is accurate.
3.5.54
All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Regular Marine Travel Route Plan, the travelling speed
of vessels must not exceed 5 knots when crossing the edge of the Brothers Marine
Park. The Contractor will continue to provide training for skippers to ensure
that their working vessels travel from source to destination to minimize
impacts on Chinese White Dolphin and avoid anchoring at Marine Department¡¦s
designated anchorage site - Sham Shui Kok Anchorage
(near Brothers Island) as far as practicable. Also, it is recommended to complete the marine
works of the Contract as soon as
possible so as to reduce the overall duration of
impacts and allow the dolphins population to recover as early as possible.
3.5.55 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.
3.5.56 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.
3.5.57 ET will keep reviewing the implementation status of
the dolphin related mitigation measures and remind the contractor to implement
the relevant measures.
3.5.58 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.
3.5.59 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.
3.5.60 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.
3.5.61 The marine travel route will shift along the edge of
the Brothers Marine Park as much as practical under the RMTR Plan. It was noted
that even though marine vessels may moor within the mooring site of BMP, commercial
activities including loading / unloading / transshipment are not allowed except
a permit is obtained. The HZMB works vessels were recommended to avoid the BMP.
3.5.62 It was noted that starting from January 2016, HSF
from the SkyPier will be re-routed north to the
northern edged of the Sha Chau and Lung Kwu Chau
Marine Park which currently has the highest density of CWD in the NWL. While
the HSF will reduce speed to 15 knots, the associated disturbance may still
affect CWD in the area. It was implied that the CWDs in the area shall be
closely followed.
3.5.63 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 21
March 2019. The mudflat surface levels at the four
established monitoring stations and the corresponding XYZ HK1980 GRID
coordinates are presented in Table 3.9 and Table 3.10.
Table 3.9 Measured
Mudflat Surface Level Results
|
Baseline Monitoring
(September 2012)
|
Impact Monitoring
(March 2019)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.173
|
816678.733
|
1.191
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.272
|
815831.553
|
1.019
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.577
|
815953.305
|
1.550
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.381
|
816151.280
|
1.206
|
Table 3.10 Comparison
of Measurement
|
Comparison of measurement
|
Remarks and
Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.013
|
0.006
|
0.241
|
Level
continuously increased
|
S2
|
0.000
|
0.022
|
0.155
|
Level continuously increased
|
S3
|
-0.008
|
-0.003
|
0.209
|
Level continuously increased
|
S4
|
-0.052
|
-0.101
|
0.275
|
Level continuously increased
|
3.6.2
This measurement result was generally and relatively higher than the
baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously
increased.
Water Quality
Monitoring
3.6.3
The mudflat monitoring covered water quality
monitoring data. Reference was made to the water quality monitoring data of the
representative water quality monitoring station (i.e. SR3(N)) as in the
EM&A Manual. The water quality
monitoring location (SR3(N)) is shown in Figure 2.1.
3.6.4 Impact water quality
monitoring in San Tau (monitoring station SR3(N)) was conducted in March 2019.
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-Mar-2019
|
7.7
|
1.9
|
1.5
|
7.8
|
3.4
|
3.1
|
04-Mar-2019
|
8.0
|
1.6
|
1.3
|
8.0
|
1.8
|
1.8
|
06-Mar-2019
|
8.0
|
2.3
|
3.6
|
7.8
|
1.7
|
1.3
|
08-Mar-2019
|
7.7
|
3.1
|
2.3
|
7.3
|
2.7
|
2.8
|
11-Mar-2019
|
7.0
|
7.7
|
8.5
|
7.3
|
5.5
|
5.2
|
13-Mar-2019
|
7.4
|
7.4
|
8.6
|
7.2
|
4.9
|
4.5
|
15-Mar-2019
|
7.0
|
2.3
|
1.7
|
7.2
|
6.7
|
2.3
|
18-Mar-2019
|
6.9
|
8.4
|
9.2
|
6.6
|
3.8
|
4.4
|
20-Mar-2019
|
7.0
|
11.2
|
13.1
|
6.7
|
4.3
|
4.5
|
22-Mar-2019
|
6.7
|
15.0
|
14.4
|
7.0
|
7.6
|
8.3
|
25-Mar-2019
|
6.6
|
12.4
|
12.6
|
7.1
|
9.7
|
11.3
|
27-Mar-2019
|
6.8
|
8.2
|
4.7
|
6.9
|
7.4
|
7.5
|
29-Mar-2019
|
7.0
|
9.5
|
3.7
|
7.0
|
10.3
|
5.8
|
Average
|
7.2
|
7.0
|
6.6
|
7.2
|
5.4
|
4.8
|
Mudflat Ecology
Monitoring
Sampling Zone
3.6.6 In order to collect baseline information of mudflats in the study
site, the study site was divided into three sampling zones (labeled as TC1,
TC2, TC3) in Tung Chung Bay and one zone in San Tau (labeled as ST) (Figure 2.1 of Appendix O). The horizontal shoreline of sampling zones TC1, TC2, TC3 and ST were
about 250 m, 300 m, 300 m and 250 m respectively (Figure 2.2 of Appendix O). Survey of horseshoe crabs,
seagrass beds and intertidal communities were conducted in every sampling zone.
The present survey was conducted in March 2019 (totally 2 sampling days on 21st
and 22nd March 2019).
3.6.7 Since the field survey of Jun.
2016, increasing number of trashes and even big trashes (Figure 2.3 of Appendix O) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Bay. Respective measures (e.g. manual clean-up) should be
implemented by responsible government agency units.
Horseshoe Crabs
3.6.8 Active search method was adopted
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 hour 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 21st and 22nd March 2019, which were
warm and humid days.
3.6.9 In June 2017, a big horseshoe
crab was tangled by a trash gill net in ST mudflat (Figure 2.3 of Appendix O). It was released to sea once
after photo recording. The horseshoe crab of such size should be inhabiting
sub-tidal environment while it forages on intertidal shore occasionally during
high tide period. If it is tangled by the trash net for few days, it may die
due to starvation or overheat during low tide period. These trash gill nets are
definitely ¡¥fatal trap¡¦ for the horseshoe crabs and other marine life. Manual
clean-up should be implemented as soon as possible by responsible units.
Seagrass Beds
3.6.10 Active
search method was adopted 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 21st (for ST, TC2 and TC3)
and 22nd (for TC1) March 2019, which were warm and humid days.
Intertidal Soft Shore Communities
3.6.11
The intertidal soft shore community surveys
were conducted in low tide period on 21st (for ST. TC2 and TC3) and
22nd (for TC1) March 2019. In every sampling zone, three 100m
horizontal transect lines were laid at high tidal level (H: 2.0m above C.D.),
mid tidal level (M: 1.5m above C.D.) and low tidal level (L: 1.0m above C.D.).
Along every horizontal transect line; ten random quadrats (0.5 m x 0.5m) were
placed.
3.6.12 Inside a quadrat, any visible epifauna was collected and was in-situ
identified to the lowest practical taxonomical resolution. Whenever possible a
hand core sample (10 cm internal diameter x 20 cm depth) of sediments was
collected in the quadrat. The core sample was gently washed through a sieve of
mesh size 2.0 mm in-situ. Any visible infauna was collected and identified. Finally the top 5 cm surface sediment was dug for visible
infauna in the quadrat regardless of hand core sample was taken.
3.6.13 All collected fauna were released after recording except some tiny individuals
that were too small to be identified on site. These tiny individuals were taken
to laboratory for identification under dissecting microscope.
3.6.14 The
taxonomic classification was conducted in accordance to the following
references: Polychaetes: Fauchald
(1977), Yang and Sun (1988); Arthropods: Dai and Yang (1991), Dong (1991);
Mollusks: Chan and Caley (2003), Qi (2004), AFCD (2018).
Data Analysis
3.6.15
Data collected from direct search and core sampling
was pooled in every quadrat for data analysis. Shannon-Weaver Diversity Index (H¡¦) and Pielou¡¦s
Species Evenness (J) were calculated
for every quadrat using the formulae below,
H¡¦= -£U ( Ni / N ) ln ( Ni / N ) (Shannon and
Weaver, 1963)
J = H¡¦ / ln S, (Pielou, 1966)
where S is the total number of species in the sample, N is the total
number of individuals, and Ni is the number of individuals of the ith species.
Mudflat Ecology Monitoring Results and Conclusion
Horseshoe Crabs
3.6.16 3 individuals of horseshoe crab, Carcinoscorpius rotundicauda,
were found in present survey. All of them were found as slightly submerged in
soft mud at TC2, while no horseshoe crab was found in TC1, TC3 and ST. Since all
found target fauna were large individuals (prosomal width >100mm), their
records are excluded from the data analysis to avoid mixing up with juvenile
population living on intertidal habitat. Photo records of the observed
horseshoe crab are shown in Figure 3.1
of Appendix O and the present survey result regarding
horseshoe crab are presented in Table
3.1 of Appendix O. The complete survey records are presented in Annex II of Appendix O.
3.6.17 3 individuals of Carcinoscorpius rotundicauda
with average body size 270mm were found in TC2. Although the searching rate was
low (0.75 ind. hr-1 person-1) for TC2, it made great participation of horseshoe
crab searching in this sampling zone due to the low search record in previous
monitoring. There were occasional records of 1 to 4 individuals between March
and September throughout the monitoring period. The maximum record was 6
individuals only in June 2016.
3.6.18 Two of the observed horseshoe
crabs were a mating pair with large body sizes (prosomal width: Male 280mm;
Female 310mm), which were nearly burrowing in soft mud at low tidal level (0.5-
1.0m above C.D.) (Figure 3.2 of Appendix
O). The mating pair indicated the breeding of horseshoe crab could be
possible along the coast of Tung Chung Wan, as long as
suitable substratum was available. It is estimated the searching rate will be
higher in next survey (June.2019), due to the warmer and more humid weather in
following months (April ¡V September). The suitable breeding period of target
fauna is believed in wet season, more mating pairs and the tiny individuals
(i.e. newly hatched) were usually recorded in June and September every year (Figure 3.3 of Appendix O).
3.6.19 Despite of mating pair, a large
individual (Prosomal width: 290mm) was found in TC2 (Figure 3.4 of Appendix O). Based on its size, 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. This
large individual might move onto intertidal shore occasionally during high tide
for foraging and breeding. Because it should be inhabiting sub-tidal habitat
most of the time. This record is excluded from the data analysis to avoid
mixing up with juvenile population living on intertidal habitat. The searching
record of the horseshoe individual is estimated to increase in next survey
(June 2019), since the horseshoe crab activity would increase gradually with
the warmer weather instead of being inactive and burrowed in sediments.
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 September 2013, March 2014 and September 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 crabs population might be restored in the natural habitat.
Through a personal conversation with Prof. Shin, about 100 individuals were
released in the sampling zone ST on 20 June 2013. All of them were marked with color tape and internal chip detected by specific chip
sensor. There should be second round of release between June and September 2014
since new marked individuals were found in the survey of September 2014.
3.6.21 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 In
present survey, only 3 individuals of horseshoe crab were observed in TC2 while
no target fauna was found in ST, TC1 and TC3. Although there were horseshoe
crabs found in TC2, all of them were large individuals which are excluded from
the analysis. The search record for each sampling zone was 0 ind.
hr-1person-1. Figure 3.5 of Appendix O and 3.6
of Appendix
O show the changes of number of individuals,
mean prosomal width and search record of horseshoe crabs Carcinoscorpius rotundicauda
and Tachypleus tridentatusin
respectively in each sampling zone throughout the monitoring period.
3.6.23 To consider the entire monitoring
period for TC3 and ST, medium to high search records (i.e. number of
individuals) of both species (Carcinoscorpius rotundicauda and Tachypleus tridentatusin) were usually found in wet
season (June and September). The search record of ST was higher from September
2012 to June 2014 while it was replaced by TC3 from September 2014 to June
2015.The search records were similar between two sampling zones from September
2015 to June 2016. In September 2016, the search record of Carcinoscorpius rotundicauda
in ST was much higher than TC3. From March to June 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 September 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 September. One possible reason was that
the serial cyclone hit decreased horseshoe crab activity (totally 4 cyclone
records between June and September 2017, to be discussed in 'Seagrass survey'
section). From December 2017 to September 2018, the search records of both
species increased again to low-moderate level in ST. Relatively higher population
fluctuation of Tachypleus tridentatus
was observed in TC3.
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. There were occasional records of 1 to 4 individuals
between March and September throughout the monitoring period. The maximum
record was 6 individuals only in June 2016.
Seasonal variation of horseshoe crab population
3.6.25
Throughout the monitoring period, the search
records of horseshoe crabs were fluctuated and at moderate ¡V very low level in
March (Figures
3.4 and 3.5 of Appendix O).
Low ¡V Very low search record was found in March 2013, totally 17 ind. of Tachypleus tridentatus and
0 ind. of Carcinoscorpius rotundicauda were
found in TC1, TC3 and ST. Compare with the search record of Mar 2013, the
numbers of Tachypleus tridentatus were
increased by more than 2 times in March 2014 and 2015 (46 ind. in 2014 and 45
ind. in 2015); the number of Carcinoscorpius rotundicauda raise to 20 and 60 ind. in March 2014 and
2015 respectively. In March 2016, the search record dropped obviously. Only 1
and 23 ind. of Tachypleus tridentatus
and Carcinoscorpius rotundicauda were
found, respectively. Then, the search records rise again in March 2017 and
March 2018. The number of Tachypleus tridentatus was increased to 14 and 44 ind., while that
of Carcinoscorpius rotundicauda rise
again to 33 and 31 ind. in March 2017 and 2018, respectively. Throughout the
monitoring period, similar distribution of horseshoe crabs
population were found in March. Most of the horseshoe crabs were found in TC3
and ST, while occasional records of 1 to 3 individuals in TC1 and TC2 found. In
March 2019, 3 ind.of Carcinoscorpius rotundicauda
were observed in TC2. However, all of them were large individuals (prosomal
width >100mm), their records are excluded from the data analysis to avoid
mixing up with the juvenile population living on intertidal habitat.
3.6.26 The
search record of horseshoe crab declined obviously in all sampling zones during
dry season especially December (Figures
3.5 and 3.6 of Appendix
O) throughout the monitoring period. Very low
¡V low search record was found in December from 2012 to 2015 (0-4 ind. of Carcinoscorpius rotundicauda
and 0-12 ind. of Tachypleus tridentatus).
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).
Compare with the search record of December from 2012 to 2015, which of December
2016 were much higher relatively. There were totally 70 individuals of Carcinoscorpius rotundicauda
and 24 individuals of Tachypleus tridentatus
in TC3 and ST. Since the survey was carried in earlier December with warm and
sunny weather (~22 ºC during dawn according to Hong Kong Observatory database, Chek Lap Kok station on 5
December 2016), the horseshoe crab was more active (i.e. move onto intertidal
shore during high tide for foraging and breeding) and easier to be found. In
contrast, there was no search record in TC1 and TC2 because the survey was
conducted in mid-December with colder and cloudy weather (~20ºC during dawn on
19 December). The horseshoe crab activity would decrease gradually with the
colder climate. In December of 2017 and 2018, very low search records were
found again as mentioned above.
3.6.27 From September 2012 to December 2013, Carcinoscorpius rotundicauda
was less common species relative to Tachypleus tridentatus.
Only 4 individuals were ever recorded in ST in December 2012. This species had
ever been believed of very low density in ST hence the encounter rate was very
low. In March 2014, it was found in all sampling zones with higher abundance in
ST. Based on its average size (mean prosomal width 39.28-49.81 mm), it
indicated that breeding and spawning of this species had occurred about 3 years
ago along the coastline of Tung Chun Wan. However, these individuals were still
small while their walking trails were inconspicuous. Hence there was no search
record in previous sampling months. Since March 2014, more individuals were
recorded due to larger size and higher activity (i.e. more conspicuous walking
trail).
3.6.28 For Tachypleus tridentatus,
sharp increase of number of individuals was recorded in ST during the wet
season of 2013 (from March to September). 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 March and June 2014 and
followed by a rapid decline in September 2014. Then the number of individuals
fluctuated slightly in TC3 and ST until March 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 March 2014. Then it varied slightly between 35-65 mm
from September 2014 to March 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 June 2017, the number of individuals increased sharply
again in TC3 and ST. Although mating pair of Tachypleus tridentatus was not found in previous
surveys, there should be new round of spawning in the wet season of 2016. The
individuals might have grown to a more conspicuous size in 2017 accounting for
higher search record. In September 2017, moderate numbers of individual were
found in TC3 and ST indicating a stable population size. In September 2018, the
population size was lower while natural mortality was the possible cause.
3.6.29 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 tridentatusbecame common again and
distributed in TC3 and ST mainly. 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
3.6.30 Figure
3.7 of Appendix O shows the changes of prosomal width of Carcinoscorpius rotundicauda
and Tachypleus tridentatus
in TC3. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between September
2012 and December 2013 hence the data were lacking. In March 2014, the major
size (50% of individual records between upper (top box) and lower quartile
(bottom box) ranged 40-60 mm while only few individuals were found. From March
2014 to September 2018, the median prosomal width (middle line of whole box)
and major size (whole box) decreased after March of every year. It was due to
more small individuals found in June indicating new rounds of spawning. Also,
there were slight increasing trends of body size from June. to March of next
year since 2015. It indicated a stable growth of individuals. Focused on larger
juveniles (upper whisker), the size range was quite variable (prosomal width
60-90 mm) along the sampling months. Juveniles reaching this size might
gradually migrate to sub-tidal habitats.
3.6.31 For Tachypleus tridentatus,
the major size ranged 20-50 mm while the number of individuals fluctuated from
September 2012 to June 2014. Then a slight but consistent growing trend was
observed from September 2014 to June 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 March to September 2016,
slight increasing trend of major size was noticed again. From December 2016 to
June 2017, similar increasing trend of major size was noted with much higher
number of individuals. It reflected new round of spawning. In September 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 June and
September 2017 (to be discussed in the 'Seagrass survey' section). From
December 2017 to September 2018, 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
3.6.32 Figure
3.8 of Appendix O shows the changes of prosomal width of Carcinoscorpius rotundicauda
and Tachypleus tridentatus
in ST. As mentioned above, Carcinoscorpius rotundicauda was rarely found between September 2012
and December 2013 hence the data were lacking. From March 2014 to September
2018, the size of major population decreased and more small individuals (i.e.
lower whisker) were recorded after June of every year. It indicated new round
of spawning. Also, there were similar increasing trends of body size from September
to June of next year between 2014 and 2017. It indicated a stable growth of
individuals. 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
March 2017. It reflected juveniles reaching this size would gradually migrate
to sub-tidal habitats.
3.6.33 For Tachypleus tridentatus, a consistent growing trend
was observed for the major population from December 2012 to December 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 March
to September 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 December 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 March 2016, the number of individuals was very few in ST
that no box plot could be produced. In June 2016, the prosomal width of major
population ranged 50-70 mm. But it dropped clearly to 30-40 mm in September
2016 followed by an increase to 40-50 mm in December 2016, 40-70 mm in March
2017 and 50-60mm in June 2017. Based on overall higher number of small
individuals from June 2016 to September 2017, it indicated another round of
spawning. From September 2017 to June 2018, the major size range increased
slightly from 40-50 mm to 45-60 mm indicating a continuous growth. In September
2018, decrease of major size was noted again that might reflect new round of
spawning. Throughout the monitoring period, the larger juveniles ranged 60-80
mm in prosomal width. Juveniles reaching this size would gradually migrate to
sub-tidal habitats.
3.6.34 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. The population
size was consistent in these two sampling zones. For Tachypleus tridentatus, small individuals were
rarely found in both zones from 2014 to 2015. It was believed no occurrence of
successful spawning. The existing individuals (that recorded since 2012) grew
to a mature size and migrated to sub-tidal habitat. Hence the number of
individuals decreased gradually. From 2016 to 2018, new rounds of spawning were
recorded in ST while the population size increased to a moderate level.
3.6.35 Although
no horseshoe crab was recorded in TC3 and ST in March 2019, it was the first
monitoring of 2019. The search record of horseshoe crab was usually fluctuated
and influenced by weather condition and tidal level. Overall population growth
of horseshoe crab in 2019 should be evaluated from the results of the following
surveys as well, while it is estimated to maintain a moderate level as 2018.
Impact of the HKLR
project
3.6.36 It was
the 26th survey of the EM&A programme during
construction period. Based on the monitoring results, no detectable impact on
horseshoe crab was revealed due to HKLR project. The population change was
mainly determined by seasonal variation, no abnormal phenomenon of horseshoe
crab individual, such as large number of dead individuals on the shore) had
been reported.
Seagrass Beds
3.6.37 Only seagrass species Halophila ovalis was found in present
survey, which was found in ST. There were one medium -large sized and three
smalls sized of seagrass bed. The largest rand had area ~1000m2 in
medium vegetation coverage (50-60%) and located at tidal zone 1.5- 2.0 m above
C.D nearby mangroves plantation. At close vicinity, three smalls sized of Halophila ovalis beds with area ~ 1 m2
were observed. Two of them were in high vegetation coverage (90-100%) and the
remaining one was in medium vegetation coverage (50-60%). Another seagrass
species Zostera japonica was not found in present
survey. Table 3.2 of Appendix O summarizes the results of present seagrass beds survey and the
photograph records of the seagrass are shown on Figure 3.9 of Appendix O. The complete record throughout the
monitoring period is presented in Annex
III of Appendix O.
3.6.38 Since the commencement of the EM&A monitoring programme, two species of seagrass Halophila ovalis and Zostera japonica
were recorded in TC3 and ST (Figure 3.10
of Appendix O). In general, Halophila ovalis was occasionally found
in TC3 in few, small to medium patches. But it was commonly found in ST in
medium to large seagrass bed. Moreover, it had sometimes grown extensively and
had covered significant mudflat area at 0.5-2.0 m above C.D. between TC3 and
ST. Another seagrass species Zostera japonica
was found in ST only. It was relatively lower in vegetation area and co-existed
with Halophila ovalis nearby the
mangrove strand at 2.0 m above C.D..
3.6.39 According to the previous results, majority of seagrass bed was confined
in ST, the temporal change of both seagrass species were
investigated in details:
Temporal variation of seagrass beds
3.6.40 Figure
3.11 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 Mach 2013 that grew within the large
patch of seagrass Halophila ovalis. Then, the patch size increased and
merged gradually with the warmer climate from March to June 2013 (15 m2).
However, the patch size decreased and remained similar from September 2013 (4 m2)
to March 2014 (3 m2). In June 2014, the patch size increased
obviously again (41 m2) with warmer climate followed by a decrease
between September 2014 (2 m2) and December 2014 (5 m2).
From March to June 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
September 2015 to June 2016, it was found coexisting with seagrass Halophila
ovalis with steady increasing patch size (from 44 m2 to 115 m2)
and variable coverage. In September 2016, the patch size decreased again to (38
m2) followed by an increase to a horizontal strand (105.4 m2)
in June 2017. And it did no longer co-exist with Halophila ovalis.
Between September 2014 and June 2017, an increasing trend was noticed from
September to June of next year followed by a rapid decline in September of next
year. It was possibly the causes of heat stress, typhoon and stronger grazing
pressure during wet season. However, such increasing trend was not found from
September 2017 to March 2019 (present survey) while no 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
September 2012. The total seagrass bed area grew steadily from 332.3 m2
in September 2012 to 727.4 m2 in December 2013. Flowers were
observed in the largest patch during its flowering period. In March 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 June 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 September
2014, the total seagrass area declined sharply to 1111m2. There were
only 3-4small to large patches (6-253 m2) at high tidal level and
1large patch at low tidal level (786 m2). Typhoon or strong water
current was a possible cause (Fong, 1998). In September 2014, there were two
tropical cyclone records in Hong Kong (7th-8th September: no cyclone name,
maximum signal number 1; 14th-17th September: Kalmaegi, maximum signal number 8SE) before the seagrass
survey dated 21st September 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
December 2014, all the seagrass patches of Halophila
ovalis disappeared in ST. Figure 3.12
of Appendix
O shows the difference of the original
seagrass beds area nearby the mangrove vegetation at high tidal level between
June 2014 and December 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 unfavorable
condition to Halophila ovalis (Fong,
1998). As mentioned above, there were two tropical cyclone records in Hong Kong
in September 2014. The strong water current caused by the cyclones might have
given damage to the seagrass beds.
3.6.44 Prolonged light deprivation due to turbid
water would be another unfavorable condition. Previous studies reported that Halophila
ovalis had little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999). Hence,
the seagrass bed of this species was susceptible to temporary light deprivation
events such as flooding river runoff (Long staff 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 September 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 September 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, was 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
September 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 in 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 3.12 of Appendix O shows the recolonization of seagrass bed in ST from December 2014
to June 2017. From March to June 2015, 2-3 small patches of Halophila ovalis were newly found
co-inhabiting with another seagrass species Zostera japonica. But the total patch area of Halophila ovalis was still very low compare with previous records.
The recolonization rate was low while cold weather and insufficient sunlight
were possible factors between December 2014 and March 2015. Moreover, it would
need to compete with seagrass Zostera japonica
for substratum and nutrient, because Zostera japonica
had extended and covered the original seagrass bed of Halophila ovalis at certain degree. From June 2015 to March 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 its competitor Zostera japonica. In June 2016, the total
seagrass area increased sharply to 4707.3m2. Similar
to the previous records of March to June 2014, the original patch area
of Halophila ovalis increased further
to a horizontally long strand. Another large seagrass bed colonized the lower
tidal zone (1.0-1.5 m above C.D.). In September 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-selected seagrass. In December 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. The total seagrass bed decreased to 12550 m2.
From March to June 2017, the seagrass bed area remained generally stable
(12438-17046.5 m2) but the vegetation coverage fluctuated (20-50% in
March 2017 to 80-100% in June 2017). The whole recolonization process took
about 2.5 years.
Second disappearance of
seagrass bed
3.6.48 In September 2017, the whole seagrass bed of Halophila ovalis disappeared again along the shore of TC3 and ST (Figure 3.12 of Appendix O). Similar to the first disappearance of
seagrass bed occurred between September and December 2014, strong water current
(e.g. cyclone) or deteriorated water qualities (e.g. high turbidity) was the
possible cause.
3.6.49 Between the survey periods of June and September 2017, there were
four tropical cyclone records in Hong Kong (Merbok in
12-13th, June; Roke in 23rd,
Jul.; Hato in22-23rd, Aug.; Pakhar in 26-27th, Aug.) (online database of
Hong Kong Observatory). All of them reaches signal 8 or above, especially Hato with highest signal 10.
3.6.50 According to the water quality monitoring results (July to August
2017) of the two closest monitoring stations SR3 and IS5 of the respective
EM&A programme, the overall water quality was in
normal fluctuation. There was an exceedance of suspended solids (SS) at SR3 on
12 July 2017. The SS concentration reached 24.7 mg/L during mid-ebb tide, which
exceeded the Action Level (≤23.5 mg/L). But it 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 has believed the
cause of serial cyclone hit in July and August 2017. Based on previous
findings, the seagrass beds of both species were expected to recolonize in the
mudflat as long as the vicinal water quality was
normal. The whole recolonization process (from few, small patches to extensive
strand) would be gradually lasting at least 2 years. From December 2017 to
March 2018, there was still no recolonization of few, small patches of seagrass
at the usual location (Figure 3.12 of Appendix O). It was different from the previous round (March 2015 - June
2017). Until June 2018, the new seagrass patches with small-medium size were
found at the usual location (seaward side of mangrove plantation at 2.0 m C.D.)
again, indicating the recolonization. However, the seagrass bed area decreased
sharply to 22.5 m2 in September 2018. Again, it was believed that
the decrease was due to the hit of the super cyclone in September 2018 (Mangkhuton 16th September, highest signal 10).
In March 2019 (present survey), the seagrass bed area increased again.
Relatively, it would occur later and slower than the previous round (more than
2 years).
Impact of the HKLR project
3.6.52 It was
the 26th survey of the EM&A programme
during construction period. Throughout the monitoring period, the disappearance
of seagrass beds was believed the cause of cyclone hits rather than impact of
HKLR project. The seagrass bed is recolonizing since there has been a gradual
increase in the size and number of that after the hit of the super cyclone in
September 2018.
Intertidal Soft
Shore Communities
Substratum
3.6.53 Table 3.3 and Figure 3.13 of Appendix O show the substratum types along the horizontal transact at every tidal
level in all sampling zones. The relative distribution of substratum types was
estimated by categorizing the substratum types (Gravels & Boulders / Sands
/ Soft mud) of the ten random quadrats along the horizontal transect. The
distribution of substratum types varied among tidal levels and sampling zones:
¡P
In TC1, high percentages of ¡¥Gravels and
Boulders¡¦ (H: 70%; M: 60%) were recorded at high and mid
tidal levels. Relatively higher percentages of ¡¥Gravels and
Boulders¡¦ (40%) and ¡¥Soft mud¡¦ (40%) were
recorded at low tidal level.
¡P
In TC2, higher percentage of ¡¥Sands¡¦ (50%) was recorded at
high tidal level. At mid tidal level, there was higher percentage of ¡¥Soft mud¡¦
(50%) followed by ¡¥Gravels
and Boulders¡¦ (30%). At low tidal level, the major substratum
type was 'Soft mud' (60%).
¡P
In TC3, higher percentage of ¡¥Sands¡¦ (60%) was recorded
followed by ¡¥Soft
mud¡¦ (30%) at high tidal level. At mid tidal level, higher percentages of
¡¥Soft mud¡¦ (70%) and ¡¥Sands¡¦
(30%) were recorded. At low tidal level, the main substratum type was ¡¥Gravels and
Boulders¡¦ (80%).
¡P
In ST, ¡¥Gravels and Boulders¡¦ was the
main substratum type (100%) at high tidal level. At mid tidal level, there were
even distributions of ¡¥Gravels
and Boulders¡¦ (50%) and ¡¥Sands¡¦ (50%). At low tidal level, ¡¥Sands¡¦ was the main substratum type
(70%).
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.
Soft shore communities
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 14803 individuals were recorded. Mollusca was the most
abundant phylum (total abundance 13903 ind, density
463 ind. m-2, relative abundance 93.9%). The second and third
abundant phya were Arthropoda (698 ind., 23 ind. m-2,
4.7%) and Annelida (128 ind., 4 ind. m-2, 0.9%) respectively.
Relatively other phyla were very low in abundances (density £1 ind. m-2, relative abundance £0.3%). Moreover, the most diverse phylum was Mollusca (46 taxa) followed
by Annelida (9 taxa) and Arthropoda (6 taxa). There was 1 taxa
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. As reported in June 2018, taxonomic
revision of three potamidid snail species was conducted according to the latest
identification key published by Agriculture, Fisheries and Conservation
Department (details see AFCD, 2018), the species names of following gastropod
species were revised:
¡P
Cerithidea cingulata was
revised as Pirenella asiatica
¡P
Cerithidea djadjariensis was
revised as Pirenella incisa
¡P
Cerithidea rhizophorarum was
revised as Cerithidea moerchii
Moreover, taxonomic
revision was conducted on another snail species while the specie name was
revised.:
¡P
Batillaria bornii was revised as Clypeomorus bifasciata
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 (3268- 4322 ind.) varied among the four sampling zones while the
phyla distributions were similar. In general, Mollusca was the most dominant
phylum (no. of individuals: 3037-4119 ind.; relative abundance 92.4-95.3%;
density 416-549 ind. m-2). Other phyla were much lower in number of
individuals. Arthropoda (78-255 ind.; 2.4-6.5 %; 10-34 ind. m-2) and
Annelida (11-81 ind.; 0.3-2.5 %; 1-11 ind. m-2) were common phyla
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 (42-100 ind. m-2). Few listed species
of high or very high density (> 100 ind. m-2) were regarded as
dominant species. Other listed species of lower density (< 42 ind. m-2)
were regarded as common species.
3.6.59 In TC1, the substratum was mainly
¡¥Gravels and Boulders¡¦ at high and mid tidal levels. The high tidal level was
clearly dominated by rock oyster Saccostrea
cucullata (190 ind. m-2, relative
abundance 37%) at high density followed by gastropod Monodonta labio (61 ind. m-2, 12%). At
mid tidal level, rock oyster Saccostrea cucullata (108 ind. m-2, 22%), Monodonta labio (74
ind. m-2, 15%) and Batillaria multiformis (63 ind. m-2, 13%) were abundant
at low - moderate densities. At low tidal level (main substratum types ¡¥Gravels
and Boulders¡¦ or ¡¥Soft mud¡¦), rock oyster Saccostrea
cucullata (146 ind. m-2, 26 %) was
more abundant at moderate density and gastropods Lunella coronate (81ind. m-2, 15%) was found at low-moderate
densities.
3.6.60 In
TC2, the substratum types were mainly
'Sands' at high tidal level. Gastropods Pirenella incisa (102 ind. m-2, 21 %) was abundant at
moderate density. Rock oyster Saccostrea cucullata (87 ind. m-2, 18 % attached on
boulder), Pirenella asiatica (74
ind. m-2, 16%) and Monodonta labio (66 ind. m-2, 14%) were abundant at
low-moderate densities. At mid tidal level (main substratum type ¡¥Soft mud¡¦),
gastropods Pirenella incisa (81
ind. m-2, 19 %) and Rock oyster Saccostrea
cucullata (74 ind. m-2, 17%) were
abundant at low- moderate density. At low tidal level (main substratum type
¡¥Soft mud¡¦), Rock Oyster Saccostrea cucullata (99 ind. m-2, 34%) was abundant at
moderate density and followed by gastropod Monodonta labio (42 ind. m-2, 10 %) at
low- moderate density.
3.6.61 In TC3, the substratum types were either ¡¥Sands¡¦ or
¡¥Soft mud¡¦ at high and mid tidal levels. At high tidal level, Rock oyster Saccostrea
cucullata (111 ind. m-2, 20%) was
dominant followed by gastropods Batillaria multiformis (87 ind. m-2, 16%) and Monodonta labio (55
ind. m-2, 10%) at low-moderate densities. At mid tidal level, Rock
oyster Saccostrea cucullata (118 ind. m-2,
17%) was dominant followed by gastropods Batillaria
zonalis (111 ind. m-2, 16%) and Batillaria multiformis
(88 ind. m-2, 12%) at low-moderate densities .At low tidal level
(major substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea cucullata (135 ind. m-2, 28 %, attached on
boulders) was dominant at moderate density and followed by gastropod Pirenella incisa
(70 ind. m-2, 15 %) and Lunella
coronate (50 ind. m-2, 10%) were abundant at low-moderate
densities.
3.6.62 In ST, the major substratum type
was ¡¥Gravels and Boulders¡¦ at high tidal level. At high tidal level, Rock
oyster Saccostrea cucullata
(147 ind. m-2, 31%) was dominant at high density and followed by
gastropods Batillaria multiformis
(117 ind. m-2, 24%) were dominant at moderate densities. Batillaria zonalis (61 ind. m-2, 13%) was abundant at
low-moderate density. At mid tidal level (even distribution of ¡¥Gravals
and Boulders¡¦ and ¡¥Sand¡¦), Rock
oyster Saccostrea cucullata (165 ind. m-2, 30%) was dominant
at high density and followed by gastropods Batillaria
zonalis (85
ind. m-2, 15%), Pirenella incisa (78 ind. m-2, 14 %) and Batillaria multiformis
(66 ind. m-2, 12%) at low-moderate densities. At low tidal level (major substratum: ¡¥Sands¡¦), rock oyster Saccostrea cucullata
(90 ind. m-2, 32 %, attached on boulders) was dominant at moderate density and followed by gastropod
Pirenella incisa (50
ind. m-2, 18 %) at low-moderate
densities.
3.6.63 In general, there was no
consistent zonation pattern of species distribution across all sampling zones
and tidal levels. The species distribution was determined by the type of
substratum primarily. In general, Rock Oyster Saccostrea cucullata (847 ind.),
gastropods Batillaria multiformis
(246 ind.), Batillaria zonalis (146
ind.), Monodonta labio (135
ind.), Pirenella incise (128 ind.) and Lunella coronate (81 ind.) were the most common
species on gravel and boulders substratum. Rock oyster Saccostrea cucullata (624 ind.), Pirenella asiatica (226
ind.), Batillaria multiformis
(176 ind.), Monodonta labio (162
ind.), Batillaria zonalis (111
ind.), Pirenella incise (102 ind.) and Lunella coronate (50 ind.) were the most common
species on sandy and soft mud substrata.
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, the mean species number was
similar (7-12 spp. 0.25 m-2) among the four sampling zones. The mean
densities of TC1 and TC3 (524 and 572 ind. m-2) were higher than ST
(438 ind. m-2) followed by TC2 (436 ind. m-2). The higher
densities of TC1 and TC3 are due to the relatively high number of individuals
in each quatrat. Moreover, TC1 and TC3 was relatively
higher in H' (2.0) and J (0.8) due to higher species number and even taxa
distribution. Lower H¡¦ (1.6) was resulted in TC1, which was due to the lower
species number. The value of J at TC2 was 0.8, which was similar
to that of TC1 and TC3. In ST, higher densities were mainly accounted by
1-2 abundant gastropods. It resulted in lower H¡¦ (1.4) and J (TC2: 0.7).
3.6.66 In the present survey, no clear trend of mean species number, mean
density, H¡¦ and J observed among the tidal level.
3.6.67 Figures 3.14 to 3.17 of Appendix O show
the temporal changes of mean species number, mean density, H¡¦ and J at every
tidal level and in every sampling zone along the sampling months. In general,
all the biological parameters fluctuated seasonally throughout the monitoring
period. Lower mean species number and density were recorded in dry season
(December) but the mean H' and J fluctuated within a limited range.
3.6.68 From June to December 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 unfavorable change reflecting
environmental stresses. The heat stress and serial cyclone hit were believed
the causes during the wet season of 2017.From March 2018 to March 2019,
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 26th 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. Abnormal
phenomena (e.g. rapid, consistent or non-seasonal decline of fauna densities
and species number) were not recorded.
3.7
Solid and
Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical Waste
Producer on 12 July 2012 for the Contract. Sufficient
numbers of receptacles were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental
Licenses and Permits
3.8.1
The valid environmental licenses and permits during
the reporting period are summarized in Appendix L.
4
Environmental Complaint and
Non-compliance
4.1.1
The detailed air quality, noise, water quality and dolphin exceedances
are provided in Appendix M. Also, the summaries of
the environmental exceedances are presented as follows:
Air
Quality
4.1.2
No Action Level and Limit level exceedances
of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6 during the reporting
month.
Noise
4.1.3 No Action/Limit Level exceedances for noise were recorded during
daytime on normal weekdays of the reporting period.
Water Quality
4.1.4 No Action and Limit Level
exceedances of turbidity level and dissolved oxygen were recorded during the
reporting period. No Limit Level exceedance of suspended solids were recorded
during the reporting period. 3 Action Level exceedances of suspended solids
level were recorded during the reporting period. The
exceedances were considered as non-contract related.
Dolphin
4.1.5 There was a Limit Level exceedance of dolphin monitoring for the
quarterly monitoring data (between March 2019 ¡V May 2019). According to the
contractor¡¦s information, the marine activities undertaken for HKLR03 during
the quarter of March 2019 to May 2019 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 work area 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, two complaints in relation to the environmental impacts were
received on 3 April 2019 and 30 April 2019. A summary of environmental
complaint 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
|
N/A
|
EPD (ENPO referred the
email from EPD to HyD, SOR, Contractor and ET) on
3 April 2019
|
Dust
|
COM-2019-163
|
SOR referred the email
from HyD to Contractor, ET and IEC/ENPO on 30
April 2019
|
Waste
|
4.2.2 Referring to the
complaint received on 3 April 2019, soil/earth handling work and landscaping work were conducted on the date
of complaint (3 April 2019). Watering on the exposed soil and the haul road of
the construction site of Contract No.
HY/2011/03 were
undertaken on that day.
4.2.3 1-hr TSP and 24-hr TSP monitoring
were conducted at air monitoring station AMS6 which is close to the
construction site. No Action and Limit level exceedances of 24-hr TSP and 1-hr
TSP monitoring at station AMS6 on 2 and 3 April 2019 were recorded
respectively.
4.2.4 During ET¡¦s inspection on 4 April
2019, soil/earth handling work and landscaping work were conducted at the
construction site. Exposed soil surfaces were observed wet which showed that
adequate dust suppression measures had been implemented.
Dust emissions arising from the construction
site of Contract No. HY/2011/03 was not observed on 4 April 2019. Site access at S7 was also
observed with regular cleaning and washing. The Contractor has been
implementing water spraying during their daily site activities including
spraying the haul road by water truck, manual spraying onto compacted soil
stockpile. Based on
investigation result, there was no observation of dust emissions arising from
the Contract No. HY/2011/03.
4.2.5 Referring to the complaint
received on 30 April 2019, an opened bag of rubbish at the concerned bus stop,
with some rubbish scattered around the nearby landscaping area were observed
during ET¡¦s inspection on 30 April 2019. Given that there was no work being
carried out in the concerned landscaping area), which has been opened to the
public, the rubbish was unlikely to be due to the works. Nevertheless, the
Contractor has removed the rubbish on 2 May 2019. It was noted that the closest
rubbish bin was about 150m away from the concerned bus stop.
4.2.6 Based on our investigation
result, there was no observation of works in the area of complaint on issue of
general refuse arising from the Contract No. HY/2011/03.
4.2.7 The
details of cumulative statistics of Environmental Complaints are provided in Appendix N.
4.2.8 No notification of summons and
prosecution was received during the reporting period. Statistics on
notifications of summons and successful prosecutions are summarized in Appendix M.
4.2.9
5
Comments, Recommendations and Conclusion
5.1.1
According to the environmental
site inspections undertaken during the reporting period, the following
recommendations were provided:
¡P
The Contractor was reminded to remove / provide drip trays
for the chemical containers at Depressed Roundabout.
¡P
The Contractor was reminded to clear the oil stain
from N13A and treat the waste as chemical waste.
¡P
The Contractor was reminded to remove the stagnant
water from N4, S23.
¡P
The Contractor was reminded to remove the waste and
provide drip tray for the chemical drum at S15.
¡P
The Contractor was reminded to remove the construction
waste from LCSD Depot.
¡P
The Contractor was reminded to dispose of the waste
battery as chemical waste at S28.
¡P
The Contractor was reminded to remove the waste on the
ground from LCSD Depot.
¡P
The Contractor was reminded to remove the unused
chemical container at N4.
¡P
The Contractor was reminded to remove the waste from
N13A, S7, N4, S28, DPR, S15, S23, LCSD Depot and Depressed Roundabout.
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-seventh Quarterly EM&A Report which
summarizes the monitoring results and audit findings of
the EM&A programme during the reporting period
from 1 March 2019 to 31 May 2019.
Air Quality
5.3.2
No Action Level and Limit Level exceedances
of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6 during the reporting period.
Noise
5.3.3
No Action/Limit Level exceedances for noise were recorded during daytime
on normal weekdays of the reporting period.
Water Quality
Dolphin
5.3.5
There was a Limit Level exceedance of dolphin monitoring for the
quarterly monitoring data between March 2019 ¡V May 2019.
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 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 1, 6, 13, 20 and 29 March 2019; 3, 10, 17 and 26 April 2019; and 3, 8, 15, 22 and 31 May 2019. Recommendations on remedial actions were given to the Contractors
for the deficiencies identified during the site inspections.
5.3.12 Two complaints were received in relation to the environmental impact
during the reporting period. Referring to the complaint received on 3 April
2019, there was no observation of dust emissions arising from the Contract No.
HY/2011/03 based on investigation result. Referring to the complaint received
on 30 April 201 (Complaint No.
COM-2019-163), there was no observation of works in the area of complaint on issue of
general refuse arising from the Contract No. HY/2011/03 based on investigation result.
5.3.13 No notification of summons and prosecution was received during the
reporting period.