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.
17 (September to November 2016)
25
April 2017
Revision 1
Main Contractor Designer
Executive Summary
The Hong Kong-Zhuhai-Macao Bridge (HZMB) Hong
Kong Link Road (HKLR) serves to connect the HZMB Main Bridge at the Hong Kong
Special Administrative Region (HKSAR) Boundary and the HZMB Hong Kong Boundary
Crossing Facilities (HKBCF) located at the north eastern waters of the Hong
Kong International Airport (HKIA).
The HKLR project has been separated into two
contracts. They are Contract No.
HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between
Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter referred to
as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong
Kong Link Road-Section between HKSAR Boundary and Scenic Hill.
China State Construction Engineering (Hong Kong)
Ltd. was awarded by Highways Department as the Contractor to undertake the
construction works of Contract No. HY/2011/03. The main works of the Contract
include land tunnel at Scenic Hill, tunnel underneath Airport Road and Airport
Express Line, reclamation and tunnel to the east coast of the Airport Island,
at-grade road connecting to the HKBCF and highway works of the HKBCF within the
Airport Island and in the vicinity of the HKLR reclamation. The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be ¡§Designated Projects¡¨,
under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap
499) and EIA Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were
prepared for the Project. The
current Environmental Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/K for
HKBCF were issued on 22 December 2014 and 11 April 2016, respectively. These
documents are available through the EIA Ordinance Register. The construction
phase of Contract was commenced on 17 October 2012.
BMT Asia Pacific Limited has been appointed by
the Contractor to implement the Environmental Monitoring & Audit (EM&A)
programme for the Contract in accordance with the Updated EM&A Manual for
HKLR (Version 1.0) and will be providing environmental team services to the
Contract.
This is the seventeenth Quarterly EM&A
report for the Contract which summarizes the monitoring results and audit
findings of the EM&A programme during the reporting period from 1 September 2016 to 30 November 2016.
Environmental
Monitoring and Audit Progress
The EM&A programme
were undertaken in accordance with the Updated EM&A Manual for HKLR
(Version 1.0). A summary of the
monitoring activities during this reporting period is presented as below:
Monitoring Activity
|
Monitoring Date
|
September 2016
|
October
2016
|
November
2016
|
Air
Quality
|
1-hr
TSP
|
1, 7, 13, 19, 23 and 29
|
5, 11, 17 and 27
|
2, 8, 14, 18, 24 and 30
|
24-hr
TSP
|
6, 12, 17, 22 and 28
|
4, 8, 14, 20 and 26
|
1, 7, 11, 17, 23 and 29
|
Noise
|
1, 7, 13, 19 and 29
|
5, 11, 17 and 27
|
2, 8, 14, 24 and 30
|
Water
Quality
|
2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 26, 28
and 30
|
3, 5, 7, 10, 12, 14, 17, 19, 24, 26, 28 and
31
|
2, 4, 7, 9, 11, 14, 16, 18, 21, 23, 25, 28
and 30
|
Chinese
White Dolphin
|
13, 14, 21 and 23
|
4, 7, 11 and 13
|
2, 7, 18 and 22
|
Mudflat
Monitoring (Ecology)
|
1, 3, 4, 17 and 18
|
--
|
--
|
Mudflat
Monitoring (Sedimentation rate)
|
1
|
--
|
--
|
Site Inspection
|
7, 14, 21 and 30
|
5,
12, 19 and 28
|
2,
9, 16, 23 and 29
|
As thunderstorm warning was hoisted by Hong Kong
Observatory on 9 Sep 2016 (from 09:15 to 14:00), water quality monitoring at
all stations for mid-flood tide on 9 Sep 2016 was cancelled for safety reason.
Due to boat availability, the dolphin monitoring
schedule was rescheduled from 26 Sep 2016 to 23 Sep 2016. As a typhoon was
approaching Hong Kong, the dolphin monitoring schedule was rescheduled from 15
Sep to 14 Sep 2016.
Due to boat availability and weather condition, the
dolphin monitoring schedule was rescheduled from 19 October 2016 to 13 October
2016.
As Strong Wind Signal No. 3 was hoisted by
Hong Kong Observatory on 17 October 2016, water quality monitoring (WQM)
was not carried out at stations SR10A and SR10B for mid-ebb tide.
As Tropical Cyclone Warning Signal No. 8 was hoisted
by Hong Kong Observatory on 21 October 2016, water quality monitoring (WQM) was
not carried out at all stations for mid-ebb tide and mid-flood tide. Due to boat availability,
the WQM could not be re-scheduled on 22 October 2016.
As Tropical Cyclone Warning Signal No.8 was hoisted by
the Hong Kong Observatory on 21 October 2016, air quality monitoring at AMS5
(Ma Wan Chung Village) and AMS6 (Dragonair Building) were cancelled for safety
reason. The monitoring was not able to be re-scheduled on 22 October 2016
because there was some problem with the equipment. Subsequent to internal
checking, the equipment is normal for operation as scheduled.
Due to boat availability, the dolphin monitoring
schedule was rescheduled from 8 November 2016 to 7 November 2016 and from 15
November 2016 to 18 November 2016.
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)
|
1
|
2
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin Monitoring
|
Quarterly
Analysis (Sep 2016 to Nov 2016)
|
0
|
1
|
The Environmental Team investigated all
exceedances and found that they were not project related.
All investigation reports for exceedances of the
Contract have been submitted to ENPO/IEC for comments and/or follow up to
identify whether the exceedances occurred related to other HZMB contracts.
Implementation of Mitigation Measures
Site inspections were carried out on a weekly
basis to monitor the implementation of proper environmental pollution control
and mitigation measures for the Project.
Potential environmental impacts due to the construction activities were
monitored and reviewed.
Complaint Log
There was one complaint received in relation to
the environmental impacts during the reporting period.
A summary of environmental complaints for this
reporting month is as follows:
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaints
|
COM-2016-098
|
11 November 2016
|
Water Quality
|
Notifications of Summons and Prosecutions
There were no notifications of summons or
prosecutions received during this reporting period.
Reporting Changes
This report has been developed in compliance
with the reporting requirements for the quarterly summary EM&A reports as
required by the Updated EM&A Manual for HKLR (Version 1.0).
The proposal for the change of Action Level and
Limit Level for suspended solid and turbidity was approved by EPD on 25 March
2013.
The revised Event and Action Plan for dolphin monitoring was approved by EPD on 6 May 2013.
The original monitoring station at IS(Mf)9
(Coordinate- East:813273, North 818850) was observed inside the perimeter silt
curtain of Contract HY/2010/02 on 1 July 2013, as such the original impact
water quality monitoring location at IS(Mf)9 was temporarily shifted outside
the silt curtain. As advised by the
Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted
to facilitate safe anchorage zone of construction barges/vessels until end of
2013 subject to construction progress.
Therefore, water quality monitoring station IS(Mf)9 was shifted to
813226E and 818708N since 1 July 2013.
According to the water quality monitoring team¡¦s observation on 24 March
2014, the original monitoring location of IS(Mf)9 was no longer enclosed by the
perimeter silt curtain of Contract HY/2010/02. Thus, the impact water quality
monitoring works at the original monitoring location of IS(Mf)9 has been
resumed since 24 March 2014.
Transect lines 1, 2, 7, 8, 9 and 11 for dolphin
monitoring have been revised due to the obstruction of the permanent structures
associated with the construction works of HKLR and the southern viaduct of
TM-CLKL, as well as provision of adequate buffer distance from the Airport
Restricted Areas. The EPD issued a
memo and confirmed that they had no objection on the revised transect lines on
19 August 2015.
1.1.2 The
HKLR project has been separated into two contracts. They are Contract No.
HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between
Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter referred to
as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong
Kong Link Road-Section between HKSAR Boundary and Scenic Hill.
1.1.3 China
State Construction Engineering (Hong Kong) Ltd. was awarded by Highways
Department (HyD) as the Contractor to undertake the construction works of
Contract No. HY/2011/03. The Contract is part of the HKLR Project and
HKBCF Project, these projects are considered to be ¡§Designated Projects¡¨, under
Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap 499) and
EIA Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for
the Project. The current
Environmental Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF
were issued on 22 December 2014 and 11 April 2016, respectively. These
documents are available through the EIA Ordinance Register. The construction
phase of Contract was commenced on 17 October 2012. Figure 1.1
shows the project site boundary.
1.1.5 This
is the seventeenth
Quarterly
Environmental Monitoring and Audit (EM&A) report for the Contract which
summarizes the monitoring results and audit findings of the EM&A programme
during the reporting period from 1 September 2016 to 30 November 2016.
1.2.1
The project organization
structure and lines of communication with respect to the on-site environmental
management structure with the key personnel contact names and numbers are shown
in Appendix A.
1.3
Construction
Programme
1.3.1
A copy of the Contractor¡¦s construction programme is
provided in Appendix B.
1.4
Construction Works Undertaken During
the Reporting Period
1.4.1
A summary of the construction activities undertaken
during this reporting period is shown in Table 1.1. The Works areas of the Contract are
showed in Appendix C.
Table 1.1 Construction
Activities during Reporting Period
Description of Activities
|
Site Area
|
Dismantling/trimming of
temporary 40mm stone platform for construction of seawall
|
Portion X
|
Construction of Seawall
|
Portion X
|
Loading and Unloading Filling
Materials
|
Portion X
|
Pipe Piling
|
Portion X
|
Excavation and Lateral Support
Works at Scenic Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Backfilling at Scenic Hill
Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Construction of Tunnel Box
Structure at Scenic Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Excavation for HKBCF to
Airport Tunnel
|
Portion X
|
Excavation for Diversion of
culvert PR9 and PR14
|
Portion X
|
Works for Diversion
|
Airport Road
|
Utilities Detection
|
Airport Road / Airport Express Line/ East Coast Road
|
Establishment of Site Access
|
Airport Road / Airport Express Line/East Coast Road
|
Mined Tunnel Excavation / Box
Jacking
|
Airport Road and Airport Express Line
|
Excavation and Lateral Support
Works at shaft 3 extension north shaft (Package T1.12.1)
|
Kwo Lo Wan Road
|
Excavation and Lateral Support
Works &Construction of Tunnel Box Structure for HKBCF to Airport Tunnel
East (Cut & Cover Tunnel)
|
Portion X
|
Excavation and Lateral Support
Works & Construction of Tunnel Box Structure for HKBCF to Airport Tunnel
West (Cut & Cover Tunnel)
|
Airport Road
|
Utility Culvert Excavation
|
Portion Y
|
Sub-structure &
superstructure works for Highway Operation and Maintenance Area Building
|
Portion Y
|
Excavation for Scenic Hill
Tunnel
|
West Portal
|
Superstructure works for
Scenic Hill Tunnel West Portal Ventilation building
|
West Portal
|
2.1
Summary of
EM&A Requirements
2.1.1
The EM&A programme requires environmental monitoring
of air quality, noise, water quality, dolphin monitoring and mudflat monitoring
as specified in the approved EM&A Manual.
2.1.2
A summary of Impact EM&A requirements is
presented in Table 2.1. The locations of air quality, noise and water quality monitoring
stations are shown as in Figure 2.1.
The transect line layout in Northwest and Northeast Lantau Survey Areas
is presented in Figure 2.2.
Table 2.1 Summary
of Impact EM&A Requirements
Environmental
Monitoring
|
Description
|
Monitoring
Station
|
Frequencies
|
Remarks
|
Air Quality
|
1-hr TSP
|
AMS 5 & AMS 6
|
At least 3 times every 6 days
|
While the
highest dust impact was expected.
|
24-hr TSP
|
At least once every 6 days
|
--
|
Noise
|
Leq (30mins),
L10 (30mins) and
L90 (30mins)
|
NMS5
|
At least once per week
|
Daytime on normal weekdays
(0700-1900 hrs).
|
Water Quality
|
¡P Depth
¡P Temperature
¡P Salinity
¡P Dissolved Oxygen
(DO)
¡P Suspended Solids
(SS)
¡P DO Saturation
¡P Turbidity
¡P pH
|
¡P Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,
¡P Control/Far Field
Stations:
CS2 & CS(Mf)5,
¡P Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A & SR10B
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 1.75 hour of the predicted time)
|
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth be less than 3
m, only the mid-depth station will be monitored).
|
Dolphin
|
Line-transect Methods
|
Northeast Lantau survey
area and Northwest Lantau survey area
|
Twice
per month
|
--
|
Mudflat
|
Horseshoe crabs, seagrass beds, intertidal soft shore communities,
sedimentation rates and water quality
|
San Tau and Tung Chung Bay
|
Once every 3 months
|
--
|
2.2.1
Table 2.2 presents
the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.
Table 2.2 Action
and Limit Levels for 1-hour TSP, 24-hour TSP and Noise
Environmental Monitoring
|
Parameters
|
Monitoring Station
|
Action Level
|
Limit Level
|
Air
Quality
|
1-hr TSP
|
AMS
5
|
352 µg/m3
|
500 µg/m3
|
AMS
6
|
360 µg/m3
|
24-hr TSP
|
AMS
5
|
164 µg/m3
|
260 µg/m3
|
AMS
6
|
173 µg/m3
|
Noise
|
Leq
(30 min)
|
NMS 5
|
When
one documented complaint is received
|
75
dB(A)
|
2.2.2
The Action and Limit
Levels for water quality monitoring are given as in Table 2.3.
Table 2.3 Action
and Limit Levels for Water Quality
Parameter
(unit)
|
Water Depth
|
Action
Level
|
Limit Level
|
Dissolved Oxygen (mg/L)
|
Surface and Middle
|
5.0
|
4.2 except 5 for Fish
Culture Zone
|
Bottom
|
4.7
|
3.6
|
Turbidity (NTU)
|
Depth average
|
27.5 or 120% of upstream
control station¡¦s turbidity at the same tide of the same day;
The action level has been
amended to ¡§27.5 and 120% of upstream control station¡¦s turbidity at the same
tide of the same day¡¨ since 25 March 2013.
|
47.0 or 130% of turbidity
at the upstream control station at the same tide of same day;
The limit level has been
amended to ¡§47.0 and 130% of turbidity at the upstream control station at the
same tide of same day¡¨ since 25 March 2013.
|
Suspended Solid (SS)
(mg/L)
|
Depth average
|
23.5 or 120% of upstream
control station¡¦s SS at the same tide of the same day;
The action level has been
amended to ¡§23.5 and 120% of upstream control station¡¦s SS at the same tide of
the same day¡¨ since 25 March 2013.
|
34.4 or 130% of SS at the
upstream control station at the same tide of same day and 10mg/L for Water
Services Department Seawater Intakes;
The limit level has been
amended to ¡§34.4 and 130% of SS at the upstream control station at the same
tide of same day and 10mg/L for Water Services Department Seawater Intakes¡¨
since 25 March 2013
|
Notes:
(1) Depth-averaged is
calculated by taking the arithmetic means of reading of all three depths.
(2) For DO, non-compliance
of the water quality limit occurs when monitoring result is lower that the
limit.
(3) For SS & turbidity
non-compliance of the water quality limits occur when monitoring result is
higher than the limits.
(4) The change to the
Action and limit Levels for Water Quality Monitoring for the EM&A works was
approved by EPD on 25 March 2013. Therefore, the amended Action and Limit
Levels are applied for the water monitoring results obtained on and after 25
March 2013.
2.2.3
The Action and Limit
Levels for dolphin monitoring are shown in Tables
2.4 and 2.5.
Table 2.4 Action
and Limit Level for Dolphin Impact Monitoring
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
STG < 70% of baseline
&
ANI < 70% of baseline
|
Limit Level
|
STG < 40% of baseline
&
ANI < 40% of baseline
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
Table 2.5 Derived
Value of Action Level (AL) and Limit Level (LL)
|
North Lantau
Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 4.2 & ANI < 15.5
|
STG < 6.9 & ANI
< 31.3
|
Limit Level
|
(STG < 2.4 & ANI
< 8.9) and (STG < 3.9 & ANI < 17.9)
|
Remarks:
(1)
STG
means quarterly average encounter rate of number of dolphin sightings.
(2)
ANI
means quarterly average encounter rate of total number of dolphins.
(3)
For
North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall
below the criteria; LL will be triggered if both NEL and NWL fall below the
criteria.
2.3.1 The
Event Actions Plans for air quality, noise, water quality and dolphin
monitoring are annexed in Appendix D.
2.4.1 Environmental mitigation measures for the contract
were recommended in the approved EIA Report. Appendix E lists the recommended mitigation measures and the implementation
status.
3
Environmental
Monitoring and Audit
3.1
Implementation of
Environmental Measures
3.1.1
In response to the site audit findings, the
Contractor have rectified all observations identified in environmental site
inspections undertaken during the reporting period. Details of site audit
findings and the corrective actions during the reporting period are presented
in Appendix F.
3.1.2
A summary of the Implementation Schedule of
Environmental Mitigation Measures (EMIS) is presented in Appendix E.
3.1.3 Regular
marine travel route for marine vessels were implemented properly in accordance
to the submitted plan and relevant records were kept properly.
3.1.4 Dolphin
Watching Plan was implemented during the reporting period.
No dolphins inside the silt curtain were observed. The relevant records were
kept properly.
3.2.1 The
monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2
respectively. Detailed impact air quality monitoring results and relevant graphical
plots are presented in Appendix G.
Table 3.1 Summary
of 1-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
September 2016
|
AMS5
|
89
|
57 - 113
|
352
|
500
|
AMS6
|
103
|
59 - 181
|
360
|
October 2016
|
AMS5
|
130
|
87 - 179
|
352
|
AMS6
|
115
|
94 - 146
|
360
|
November 2016
|
AMS5
|
135
|
67 - 228
|
352
|
AMS6
|
140
|
83 - 289
|
360
|
Table 3.2 Summary
of 24-hour TSP Monitoring Results Obtained During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
September 2016
|
AMS5
|
61
|
28 - 107
|
164
|
260
|
AMS6
|
56
|
26 - 92
|
173
|
October 2016
|
AMS5
|
33
|
10 - 45
|
164
|
AMS6
|
45
|
34 - 63
|
173
|
November 2016
|
AMS5
|
64
|
20 - 107
|
164
|
AMS6
|
73
|
28 - 98
|
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 month.
3.3
Noise Monitoring Results
3.3.1
The monitoring results for construction noise
are summarized in Table 3.3 and the
monitoring results and relevant graphical plots for this reporting
period are provided in Appendix H.
Table 3.3 Summary of Construction Noise
Monitoring Results Obtained During the Reporting Period
Reporting period
|
Monitoring Station
|
Average Leq (30 mins),
dB(A)*
|
Range of Leq (30
mins), dB(A)*
|
Action Level
|
Limit Level Leq (30
mins), dB(A)
|
September 2016
|
NMS5
|
58
|
54
- 63
|
When one documented complaint is received
|
75
|
October 2016
|
59
|
54
- 60
|
November 2016
|
59
|
59
- 61
|
3.3.2 There were no Action and Limit Level
exceedances for noise 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
During the reporting period,
an Action Level exceedance of suspended solids was recorded at station IS10
during mid-flood tide on 19 September 2016. Limit Level exceedances of
suspended solids were recorded at station IS10 and SR5 during mid-flood tide on
16 November 2016 respectively. Record of ¡§Notification of Environmental Quality
Limit Exceedances¡¨ is provided in Appendix M. No exceedances of Action and Limit Level for dissolved oxygen level
and turbidity level were recorded.
3.4.3
Water quality impact sources during the water
quality monitoring were the construction activities of the Contract, nearby
construction activities by other parties and nearby operating vessels by other
parties.
Data
Analysis
3.5.1 Distribution Analysis ¡V The
line-transect survey data was integrated with the Geographic Information
System (GIS) in order to visualize and interpret different spatial and temporal
patterns of dolphin distribution using sighting positions. Location data of dolphin groups were
plotted on map layers of Hong Kong using a
desktop GIS (ArcView© 3.1) to examine their distribution patterns in
details. The dataset was also
stratified into different subsets to examine distribution patterns of dolphin groups
with different categories of group sizes, young calves and activities.
3.5.2
Encounter rate analysis ¡V Encounter rates of
Chinese white dolphins (number of on-effort sightings per 100 km of survey
effort, and total number of dolphins sighted on-effort per 100 km of survey
effort) were calculated in NEL and NWL survey areas in relation to the amount
of survey effort conducted during each month of monitoring survey. Dolphin encounter rates were calculated
in two ways for comparisons with the HZMB baseline monitoring results as well
as to AFCD long-term marine mammal monitoring results.
3.5.3
Firstly, for the comparison with the HZMB
baseline monitoring results, the encounter rates were calculated using primary
survey effort alone, and only data collected under Beaufort 3 or below
condition would be used for encounter rate analysis. The average encounter rate of sightings
(STG) and average encounter rate of dolphins (ANI) were deduced based on the
encounter rates from six events during the present quarter (i.e. six sets of
line-transect surveys in North Lantau), which was also compared with the one
deduced from the six events during the baseline period (i.e. six sets of
line-transect surveys in North Lantau).
3.5.4
Secondly, the encounter rates were calculated
using both primary and secondary survey effort collected under Beaufort 3 or
below condition as in AFCD long-term monitoring study. The encounter rate of sightings and
dolphins were deduced by dividing the total number of on-effort sightings (STG)
and total number of dolphins (ANI) by the amount of survey effort for the
present quarterly period.
3.5.5
Quantitative grid analysis on habitat use ¡V To
conduct quantitative grid analysis of habitat use, positions of on-effort
sightings of Chinese White Dolphins collected during the quarterly impact phase
monitoring period were plotted onto 1-km2 grids among NWL and NEL
survey areas on GIS. Sighting
densities (number of on-effort sightings per km2) and dolphin
densities (total number of dolphins from on-effort sightings per km2)
were then calculated for each 1 km by 1 km grid with the aid of GIS. Sighting density grids and dolphin
density grids were then further normalized with the amount of survey effort
conducted within each grid. The
total amount of survey effort spent on each grid was calculated by examining
the survey coverage on each line-transect survey to determine how many times
the grid was surveyed during the study period. For example, when the survey boat
traversed through a specific grid 50 times, 50 units of survey effort were
counted for that grid. With the
amount of survey effort calculated for each grid, the sighting density and
dolphin density of each grid were then normalized (i.e. divided by the unit of
survey effort).
3.5.6 The
newly-derived unit for sighting density was termed SPSE, representing the
number of on-effort sightings per 100 units of survey effort. In addition, the derived unit for actual
dolphin density was termed DPSE, representing the number of dolphins per 100
units of survey effort. Among the
1-km2 grids that were partially covered by land, the percentage of
sea area was calculated using GIS tools, and their SPSE and DPSE values were
adjusted accordingly. The following
formulae were used to estimate SPSE and DPSE in each 1-km2 grid
within the study area:
SPSE = ((S / E) x 100) /
SA%
DPSE = ((D / E) x 100) /
SA%
where S =
total number of on-effort sightings
D = total number of
dolphins from on-effort sightings
E = total number of units
of survey effort
SA% = percentage of sea
area
3.5.7 Behavioural
analysis ¡V When dolphins were sighted during vessel surveys, their behaviour
was observed. Different activities
were categorized (i.e. feeding, milling/resting, traveling, socializing) and
recorded on sighting datasheets.
This data was then input into a separate database with sighting
information, which can be used to determine the distribution of behavioural
data with a desktop GIS.
Distribution of sightings of dolphins engaged in different activities
and behaviours would then be plotted on GIS and carefully examined to identify
important areas for different activities of the dolphins.
3.5.8 Ranging
pattern analysis ¡V Location data of individual dolphins that occurred during
the 3-month baseline monitoring period were obtained from the dolphin sighting
database and photo-identification catalogue. To deduce home ranges for individual
dolphins using the fixed kernel methods, the program Animal Movement Analyst
Extension, was loaded as an extension with ArcView© 3.1 along with
another extension Spatial Analyst 2.0.
Using the fixed kernel method, the program calculated kernel density
estimates based on all sighting positions, and provided an active interface to
display kernel density plots. The
kernel estimator then calculated and displayed the overall ranging area at 95%
UD level.
Summary of Survey
Effort and Dolphin Sightings
3.5.9
During the period
of September to November 2016, 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 892.57 km of survey effort was collected, with 96.5% 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, 341.30 km and
551.27 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 640.35 km, while the effort on secondary
lines was 252.22 km. Survey effort
conducted on both primary and secondary lines were considered as on-effort
survey data. A summary table of the
survey effort is shown in Annex I of
Appendix J.
3.5.12
During the six
sets of monitoring surveys in September to November 2016, a total of 13 groups
of 48 Chinese White Dolphins were sighted.
A summary table of the dolphin sightings is shown in Annex II of Appendix J.
3.5.13
For the present quarterly period, all dolphin sightings were made during
on-effort search, while all except one on-effort dolphin sightings were made on
primary lines. In addition, all
dolphin groups were sighted in NWL, and no dolphin was
sighted at all in NEL. In
fact, since August 2014, only two sightings of two lone dolphins were made respectively
in NEL during HKLR03 monitoring surveys.
Distribution
3.5.14 Distribution of
dolphin sightings made during monitoring surveys in September to November 2016
is shown in
Figure 1 of Appendix
J.
3.5.15
Dolphin
sightings made in the present quarter were mainly located around Sha Chau and
Lung Kwu Chau near western territorial boundary (Figure 1 of Appendix J).
A few sightings were
also made near Black Point, Pillar Point and Sham Wat respectively (Figure 1 of Appendix J). On the other hand, the dolphins were completely absent from the central
and western portions of North Lantau waters (Figure 1 of Appendix J).
3.5.16 All dolphin sightings were located far away
from the HKBCF and HKLR03 reclamation sites as well as along the alignment of
Tuen Mun-Chek Lap Kok Link (TMCLKL).
However, one group
of two dolphins was sighted adjacent to the HKLR alignment near Sham Wat (Figure 1 of Appendix J).
3.5.17 Sighting
distribution of dolphins during the present impact phase monitoring period
(September to November 2016) was drastically different from the one during the
baseline monitoring period (September to November 2011) In the present quarter, dolphins have disappeared from the NEL region,
which was in stark contrast to their frequent occurrence around the Brothers Islands, near Shum Shui Kok and in the
vicinity of HKBCF reclamation site during the baseline period (Figure 1 of Appendix J). The nearly complete abandonment of NEL region by the dolphins has been
consistently recorded in the past 15 quarters of HKLR03 monitoring, which has
resulted in zero to extremely low dolphin encounter rates in this area.
3.5.18
In NWL
survey area, dolphin occurrence was also very different between the baseline
and impact phase periods. During
the present impact monitoring period, much fewer dolphins occurred in this
survey area (mostly to the east of Lung Kwu Chau and west of Sha Chau) than
during the baseline period, when many dolphin groups were frequently sighted
between Lung Kwu Chau and Black Point, around Sha Chau, near Pillar Point and
to the west of the Chek Lap Kok Airport (Figure
1 of Appendix J).
3.5.19 Another
comparison in dolphin distribution was made between the four quarterly periods
of summer months in 2013-16 (Figure
2 of Appendix J). Among the four summer periods, dolphins
were regularly sighted throughout the North Lantau region in 2013, but their
usage there has gradually diminished in 2014 and subsequently to a very low
level in 2015 and 2016 with only occurrences concentrated around the Sha Chau
and Lung Kwu
Chau Marine
Park (Figure 2 of Appendix J).
Encounter Rate
3.5.20 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) (See Table
3.5).
3.5.21 To
facilitate the comparison with the AFCD long-term monitoring results, the
encounter rates were also calculated for the present quarter using both primary
and secondary survey effort. The encounter rates of sightings (STG) and dolphins (ANI) in NWL were
2.50 sightings and 9.21 dolphins per 100 km of survey effort respectively,
while the encounter rates of sightings (STG) and dolphins (ANI) in NEL were
both nil for this quarter.
Table
3.4 Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) During Reporting Period
(September to November 2016)
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 (13 & 14 Sep 2016)
|
0.00
|
0.00
|
Set 2 (21 & 23 Sep 2016)
|
0.00
|
0.00
|
Set 3 (4 & 7 Oct
2016)
|
0.00
|
0.00
|
Set 4 (11 & 13 Oct 2016)
|
0.00
|
0.00
|
Set 5 (2
& 7 Nov
2016)
|
0.00
|
0.00
|
Set 6 (18 & 22 Nov 2016)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (13 & 14 Sep 2016)
|
0.00
|
0.00
|
Set 2 (21 & 23 Sep 2016)
|
5.75
|
30.17
|
Set 3 (4 & 7 Oct
2016)
|
4.13
|
9.64
|
Set 4 (11 & 13 Oct 2016)
|
2.85
|
8.54
|
Set 5 (2
& 7 Nov
2016)
|
1.66
|
1.66
|
Set 6 (18 & 22 Nov 2016)
|
2.79
|
15.34
|
Table
3.5 Comparison of average dolphin encounter rates from impact
monitoring period (September to November 2016) 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
|
2.86 ¡Ó
1.98
|
9.85 ¡Ó 5.85
|
10.89 ¡Ó 10.98
|
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.
3.5.22
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 15 quarters of HKLR03 monitoring (Table
3.6). This is a serious concern as
the dolphin occurrence in NEL in the past few years (0.0-1.0 for ER(STG) and
0.0-3.9 for ER(ANI)) have remained exceptionally low when compared to the
baseline period (Table 3.6). Dolphins have been virtually absent from
NEL waters since January 2014, with only three groups of six dolphins sighted
there since then despite consistent and intensive survey effort being conducted
in this survey area.
Table
3.6 Comparison of Average
Dolphin Encounter Rates in Northeast Lantau Survey Area from All Quarters of
Impact Monitoring Period and Baseline Monitoring Period (Sep ¡V Nov 2011)
Monitoring Period
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
September-November 2011
(Baseline)
|
6.00 ¡Ó 5.05*
|
22.19 ¡Ó 26.81*
|
December 2012-February 2013 (Impact)
|
3.14
¡Ó 3.21
|
6.33
¡Ó 8.64
|
March-May 2013 (Impact)
|
0.42
¡Ó 1.03
|
0.42
¡Ó 1.03
|
June-August 2013 (Impact)
|
0.88
¡Ó 1.36
|
3.91
¡Ó 8.36
|
September-November
2013 (Impact)
|
1.01 ¡Ó 1.59*
|
3.77 ¡Ó 6.49*
|
December 2013-February
2014 (Impact)
|
0.45
¡Ó 1.10
|
1.34
¡Ó 3.29
|
March-May
2014 (Impact)
|
0.00
|
0.00
|
June-August
2014 (Impact)
|
0.42
¡Ó 1.04
|
1.69
¡Ó 4.15
|
September-November 2014 (Impact)
|
0.00*
|
0.00*
|
December 2014-February
2015 (Impact)
|
0.00
|
0.00
|
March-May
2015 (Impact)
|
0.00
|
0.00
|
June-August
2015 (Impact)
|
0.44
¡Ó 1.08
|
0.44
¡Ó 1.08
|
September-November 2015 (Impact)
|
0.00*
|
0.00*
|
December 2015-February
2016 (Impact)
|
0.00
|
0.00
|
March-May
2016 (Impact)
|
0.00
|
0.00
|
June-August
2016 (Impact)
|
0.00
|
0.00
|
September-November 2016 (Impact)
|
0.00*
|
0.00*
|
Notes:
1) The encounter rates
deduced from the baseline monitoring period have been recalculated based only
on survey effort and on-effort sighting data made along the primary transect
lines under favourable conditions.
2) ¡Ó denotes the standard
deviation of the average encounter rates.
3) The encounter rates in
summer months were in blue and marked with asterisk.
3.5.23
On the
other hand, the average dolphin encounter rates (STG and ANI) in NWL during the
present impact phase monitoring period (reductions of 71.0% and 75.6%
respectively) were only small fractions of the ones recorded during the
three-month baseline period, indicating a dramatic decline in dolphin usage of
this survey area as well during the present impact phase period (Table 3.7).
3.5.24
During the same summer quarters, dolphin
encounter rates in NWL during 2016 reached to the lowest point among the four
summer periods, and were much lower than the ones recorded in 2013 and 2014 (Table 3.7). Such temporal trend should be closely
monitored in the upcoming monitoring quarters.
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*
|
Notes:
1) The encounter rates deduced from the
baseline monitoring period have been recalculated based only on survey effort
and on-effort sighting data made along the primary transect lines under
favourable conditions.
2) ¡Ó denotes the standard deviation of the average encounter rates.
3) The
encounter rates in summer months were in blue and marked with asterisk.
3.5.25
As discussed recently in Hung (2016), the
dramatic decline in dolphin usage of NEL waters in the past few years
(including the declines in abundance, encounter rate and habitat use in NEL, as
well as shifts of individual core areas and ranges away from NEL waters) was
possibly related to the HZMB construction works that were commenced since 2012. It appeared that such noticeable decline
has already extended to NWL waters progressively in the past few years.
3.5.26
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).
3.5.27
For the comparison between the baseline period
and the present quarter (16th quarter of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.0051 and 0.0296 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.
3.5.28 For the
comparison between the baseline period and the cumulative quarters in impact
phase (i.e. first sixteen quarters of the impact phase being assessed), the
p-values for the differences in average dolphin encounter rates of STG and ANI
were 0.000004 and 0.000001 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).
3.5.29 As
indicated in both dolphin distribution patterns and encounter rates, dolphin
usage has been significantly reduced in both NEL and NWL survey areas during
the present quarterly period, and such low occurrence of dolphins has also been
consistently documented in previous quarters. This raises serious concern, as the
timing of the decline in dolphin usage in North Lantau
waters coincided well with the construction schedule of the HZMB-related
projects (Hung 2016).
3.5.30
To ensure the continuous usage of North Lantau
waters by the dolphins, every possible measure should be implemented by the
contractors and relevant authorities of HZMB-related works to minimize all
disturbances to the dolphins.
Group
Size
3.5.31
Group size of Chinese White Dolphins ranged from
one to eleven individuals per group in North Lantau region during September to
November 2016. The average dolphin group sizes from these three months were
compared with the ones deduced from the baseline period in September to
November 2011, as shown in Table 3.8.
Table 3.8 Comparison
of Average Dolphin Group Sizes between Reporting Period (Jun 2016 ¡V Aug 2016)
and Baseline Monitoring Period (Sep ¡V Nov 2011)
Survey Area
|
Average
Dolphin Group Size
|
Reporting
Period
|
Baseline
Monitoring Period
|
Overall
|
3.69
¡Ó 2.87 (n = 13)
|
3.72 ¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
---
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
3.69 ¡Ó 2.87 (n = 13)
|
3.92 ¡Ó 3.40 (n = 49)
|
Note:
1) ¡Ó denotes the standard deviation of the average
group size.
3.5.32
The
average dolphin group size in NWL waters during September to November 2016 was
slightly lower than the one recorded during the three-month baseline period
(Table 3.8). Most of these dolphin groups were composed of
1-4 individuals only, while there were three medium-sized groups of 5-7
individuals respectively, and one large group of eleven individuals.
3.5.33
Distribution of the larger dolphin groups (i.e.
five individuals or more per group) during the present quarter is shown in Figure 3 of Appendix
J, with comparison to the one in baseline period. During the autumn months of
2016, the three
medium-sized groups were sighted adjacent to Lung Kwu Chau and to the north of
the island, while the one large group of eleven individuals was sighted to at
the northeast corner of Lung Kwu Chau as well (Figure 3 of Appendix J). Such distribution pattern was very different
from the baseline period, when the larger dolphin groups were more frequently
sighted and more evenly distributed in NWL waters, with a few more sighted in
NEL waters (Figure
3 of Appendix J).
Habitat Use
3.5.34
From September to
November 2016, the more important habitats utilized by Chinese White Dolphins
were mostly located around Lung Kwu Chau (Figures 4a and 4b of Appendix J). One grid located to the
west of Shum Wat just to the south of the HKLR09 alignment also recorded
moderate density of dolphins. On
the contrary, all grids near HKLR03/HKBCF reclamation sites as well as TMCLKL
alignment did not record any presence of dolphins at all during on-effort
search in the present quarterly period (Figures 4b of
Appendix J).
3.5.35
However, it should
be emphasized that the amount of survey effort collected in each grid during
the three-month period was fairly low (6-12 units of survey effort for most
grids), and therefore the habitat use pattern derived from the three-month
dataset should be treated with caution.
A more complete picture of dolphin habitat use pattern should be
examined when more survey effort for each grid will be collected throughout the
impact phase monitoring programme.
3.5.36
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).
3.5.37
The density patterns were also very different in
NWL between the baseline and impact phase monitoring periods, with higher
dolphin usage throughout the area, especially around Sha Chau, near Black
Point, to the west of the airport, as well as between Pillar Point and airport
platform during the baseline period.
In contrast, the only areas with moderate to high dolphin densities were
restricted to the waters near Sha Chau and Lung Kwu Chau during the present
impact phase period. (Figure 5 of Appendix J).
Mother-calf Pairs
3.5.38
During the present quarterly period, neither
unspotted calf nor unspotted juvenile was sighted with any female in the North
Lantau region.
3.5.39
The absence of young calves in the past four
consecutive quarters was in stark contrast to their regular occurrence in North
Lantau waters during the baseline period.
This should be of a serious concern, and the occurrence of young calves
in North Lantau waters should be closely monitored in the upcoming quarters.
Activities and Associations with Fishing Boats
3.5.40
Four of the thirteen
dolphin groups were engaged
in feeding activity, while none of them was
engaged in socializing, traveling or milling/resting activity during the
three-month study period.
3.5.41
The percentage of
sightings associated with feeding activities (30.8%) was much higher than the
one recorded during the baseline period (11.6%). However, it should be noted the sample
size on total numbers of dolphin sightings during the present quarter (13
dolphin groups) was much lower than the baseline period (66 dolphin groups).
3.5.42
Distribution of dolphins engaged in various
activities during the present impact phase period and the baseline period is
shown in Figure 6 of Appendix J. The four dolphin groups engaged in
feeding activities were sighted around Lung Kwu Chau as well as to the west of
Shum Wat near the HKLR09 alignment during the present quarterly period, which
was very different from the baseline period when various dolphin activities
occurred throughout the North Lantau region (Figure
6 of
Appendix J).
3.5.43
Notably, one group of seven dolphins was found to
be associated with an operating gill-netter adjacent to Lung Kwu Chau within
the marine park during the present impact phase period.
Summary Photo-identification works
3.5.44
From September to November 2016, over 2,100 digital photographs
of Chinese White Dolphins were taken during the impact phase monitoring surveys
for the photo-identification work.
3.5.45
In total, 21 individuals sighted 34 times
altogether were identified (see summary table in Annex III
of Appendix J and photographs of identified individuals in Annex IV of Appendix J).
All of these re-sightings were made in NWL. Six individuals (CH34, NL136, NL202, NL269, NL286 and NL320) were
re-sighted multiple times during the three-month period
3.5.46
Notably,
none of these 21 individuals was also sighted in West
Lantau waters during the HKLR09 monitoring surveys from September
to November 2016. However, one
individual (NL269) was sighted in both NWL and SWL survey areas during the same
quarter, showing its extensive individual movement between different survey
areas.
Individual range use
3.5.47
Ranging patterns of the 21 individuals
identified during the three-month study period were determined by fixed kernel method,
and are shown in Annex V of Appendix
J.
3.5.48
All identified dolphins sighted in the present
quarter were utilizing NWL waters only, but have completely avoided NEL waters
where many of them have utilized as their core areas in the past (Annex V of Appendix J). This is in contrary to the extensive
movements between NEL and NWL survey areas observed in the earlier impact
monitoring quarters as well as the baseline period.
3.5.49
On the other hand, only one of these individuals
consistently utilized both North Lantau waters in the past have extended their
range use to SWL waters during the present quarter. In the upcoming quarters, individual
range use and movements should be continuously monitored to examine whether there
has been any consistent shifts of individual home ranges from North
Lantau to West or Southwest Lantau,
as such shift could possibly be related to the HZMB-related construction works
(see Hung 2015, 2016).
Action Level / Limit Level Exceedance
3.5.50
There was one Limit Level
exceedance of dolphin monitoring for the quarterly monitoring data (between
September 2016 ¡V November 2016). According to the contractor¡¦s information, the
marine activities undertaken for HKLR03 during the quarter of September 2016 ¡V
November 2016 included piling works, removal of surcharge materials, temporary
drainage diversion, ground investigation, box culvert diversion, construction
of permanent seawall and maintenance of silt curtain.
3.5.51
There is no evidence
showing the current LL non-compliance directly related to the construction
works of HKLR03 (where the amounts of working vessels for HKLR03 have been
decreasing), although the generally increased amount of vessel traffic in NEL
during the impact phase has been partly contributed by HKLR03 works since
October 2012. It should also be noted that reclamation work under HKLR03
(adjoining the Airport Island) situates in waters which has rarely been used by
dolphins in the past, and the working vessels under HKLR03 have been travelling
from source to destination in accordance with the Marine Travel Route to
minimize impacts on Chinese White Dolphin (CWD). In addition, the contractor will
implement proactive mitigation measures such as avoiding anchoring at Marine
Department¡¦s designated anchorage site ¡V Sham Shui Kok Anchorage (near Brothers
Island) as far as practicable.
3.5.52
According to Monitoring
of Chinese White Dolphins in Southwest Lantau Waters ¡V Fourth Quarterly Report
(December 2015 to February 2016) which is available on ENPO¡¦s website, with
their primary ranges centered in North and West Lantau waters, some individuals
showed apparent range shifts or extensions to Southwest Lantau waters in
2015-16. For example, three
individual dolphins (NL120, WL46 and WL221) indicated obvious shifts in their
range use from NWL to West Lantau (WL) and Southwest Lantau (SWL) waters.
Moreover, many individuals (e.g. NL212, NL260, WL200, SL55, WL232, WL237 and
WL265) have extended their ranges from WL waters to SWL waters. It remains to be seen whether some of
these individuals have permanently shifted their ranges away from their primary
ranges in North Lantau, or begin to spend more times in SWL waters as part of
their ranges.
3.5.53 ENPO updated that the Hong Kong-Zhuhai-Macao Bridge Authority (HZMBA) for
the Mainland section of Hong Kong-Zhuhai-Macao Bridge (HZMB) has commenced an
interim survey on fisheries resources and CWD in the Mainland waters. ENPO
presented the preliminary findings of the HZMBA interim survey on CWD sighting
and photo-identification works which provide solid evidence that some CWD that
were previously more often sighted in HK waters have expanded their ranges into
the Mainland waters, and some with reduced usage in HK waters. These
preliminary data were mentioned in Monitoring of Chinese White Dolphins in
Southwest Lantau Waters ¡V Fourth Quarterly Report (December 2015 to February
2016) which is available on ENPO¡¦s website.
3.5.54
A two-way ANOVA with
repeated measures and unequal sample size was conducted to examine whether
there were any significant differences in the average encounter rates between
the baseline and impact monitoring periods. The two variables that were examined
included the two periods (baseline and impact phases) and two locations (NEL
and NWL).
3.5.55
For the comparison between the baseline period
and the present quarter (16th quarter of the impact phase being
assessed), the p-values for the differences in average dolphin encounter rates
of STG and ANI were 0.0051 and 0.0296 respectively. If the alpha value is set at 0.05,
significant differences were detected between the baseline and present quarters
in both the average dolphin encounter rates of STG and ANI.
3.5.56
For the comparison between the baseline period
and the cumulative quarters in impact phase (i.e. first sixteen quarters of the
impact phase being assessed), the p-values for the differences in average
dolphin encounter rates of STG and ANI were 0.000004 and 0.000001
respectively. Even if the alpha
value is set at 0.00001, significant differences were still detected in both
the average dolphin encounter rates of STG and ANI (i.e. between the two
periods and the locations).
3.5.57
The AFCD monitoring data during September to
November 2016 has been reviewed by the dolphin specialist. During the same quarter, no dolphin was
sighted from 176.90 km of survey effort on primary lines in NEL, while three
groups of six dolphins were sighted from 255.36 km of survey effort on primary
lines in NWL. This review has confirmed that the extremely low occurrence of
dolphins reported by the HKLR03 monitoring surveys in autumn 2016 in NEL and
NWL survey area is accurate.
3.5.58
All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Regular Marine Travel Route Plan, the travelling speed
of vessels must not exceed 5 knots when crossing the edge of the marine park.
The Contractor will continue to provide training for skippers to ensure that
their working vessels travel from source to destination to minimize impacts on
Chinese White Dolphin and avoid anchoring at Marine Department¡¦s designated
anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as far as
practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
3.5.59
A meeting was held on 10
February 2017 with attendance of representative of ENPO, Resident Site Staff
(RSS), Environmental Team (ET) and dolphin specialist for Contract Nos.
HY/2010/02, HY/2011/03, HY/2012/07, HY/2012/08. The discussion/recommendation
as recorded in the minutes of the meeting, which might be relevant to HKLR03
Contract are summarized below.
3.5.60
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.
3.5.61
The dolphin specialists
of the projects confirmed that the CWD sighting around the North of Sha Chau
and Lung Kwu Chau Marine Park (SCLKCMP) has significantly decreased, and it was
apparently related to the re-routing of high speed ferry (HSF) from Skypier.
3.5.62
It was reminded that the
ETs shall keep reviewing the implementation status of the dolphin related
mitigation measures and remind the contractor to ensure the relevant measures
were fully implemented.
3.5.63
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.
3.5.64
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.
3.5.65
It was suggested that the
protection measures (e.g., speed limit control) for the Brothers Marine Park
(BMP) shall be brought forward so as to provide a better habitat for dolphin
recovery. It was noted that under the Regular Marine Travel Route (RMTR) Plan,
the contractors have committed to reduce the vessel speed in BMP. HyD updated
that the draft map of the proposed BMP was gazetted in February 2016. ENPO
updated that the BMP was approved by the Chief Executive in the Executive
Council in August 2016. The ETs were reminded to update the BMP boundary in the
RMTR Plan. The BMP was designated on 30 December 2016. It was reminded that trespassing the BMP
is not allowed under the RMTR Plan.
3.5.66
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 1 September 2016. 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 2016)
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.189
|
816678.707
|
1.044
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.257
|
815831.465
|
0.929
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.522
|
815953.252
|
1.372
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.407
|
816151.382
|
0.959
|
Table 3.10 Comparison
of Measurement
|
Comparison of
measurement
|
Remarks and Recommendation
|
Monitoring Station
|
Easting
(m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.029
|
-0.020
|
0.094
|
Level continuously increased
|
S2
|
-0.015
|
-0.066
|
0.065
|
Level continuously increased
|
S3
|
-0.063
|
-0.056
|
0.031
|
Level continuously increased
|
S4
|
-0.026
|
0.001
|
0.028
|
Level continuously increased
|
3.6.2
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2,
S3 and S4. The mudflat level is continuously increased.
Water
Quality Monitoring
3.6.3
The mudflat monitoring covered water quality
monitoring data. Reference was made
to the water quality monitoring data of the representative water quality
monitoring station (i.e. SR3) as in the EM&A Manual. The water quality monitoring location
(SR3) is shown in Figure 2.1.
3.6.4 Impact
water quality monitoring in San Tau (monitoring station SR3) was conducted in
September 2016. The monitoring parameters included dissolved oxygen (DO),
turbidity and suspended solids (SS).
3.6.5 The Impact monitoring result for SR3 were extracted and summarised
below:
Table 3.11 Impact
Water Quality Monitoring Results (Depth Average)
Date
|
Mid Ebb Tide
|
Mid Flood Tide
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
2-Sep-16
|
5.89
|
14.65
|
17.55
|
5.48
|
7.20
|
7.25
|
5-Sep-16
|
6.23
|
9.30
|
9.30
|
5.90
|
5.90
|
6.85
|
7-Sep-16
|
5.98
|
7.35
|
6.05
|
5.91
|
4.20
|
6.10
|
9-Sep-16
|
6.29
|
3.20
|
4.20
|
See Remark 1
|
See Remark 1
|
See Remark 1
|
12-Sep-16
|
5.90
|
4.75
|
4.15
|
6.59
|
2.85
|
3.35
|
14-Sep-16
|
6.86
|
5.75
|
6.80
|
6.91
|
7.05
|
8.65
|
16-Sep-16
|
6.89
|
4.85
|
5.20
|
7.13
|
5.00
|
6.45
|
19-Sep-16
|
5.66
|
9.30
|
10.60
|
5.31
|
7.65
|
9.90
|
21-Sep-16
|
5.43
|
6.35
|
10.70
|
5.53
|
6.60
|
11.95
|
23-Sep-16
|
6.15
|
5.10
|
4.25
|
5.73
|
5.75
|
6.55
|
26-Sep-16
|
5.86
|
3.20
|
5.30
|
6.23
|
4.30
|
6.00
|
28-Sep-16
|
5.78
|
10.45
|
14.10
|
6.10
|
7.75
|
9.95
|
30-Sep-16
|
5.99
|
11.20
|
13.65
|
5.75
|
10.50
|
13.15
|
Average
|
6.07
|
7.34
|
8.60
|
6.05
|
6.23
|
8.01
|
Remark:
1.
As thunderstorm warning was hoisted by Hong Kong Observatory on 9
Sep 2016 (from 09:15 to 14:00), water quality monitoring at all stations for
mid-flood tide on 9 Sep 2016 was cancelled for safety reason.
Mudflat Ecology Monitoring
Sampling
Zone
3.6.6
In order to collect baseline information of
mudflats in the study site, the study site was divided into three
sampling zones (labeled as TC1, TC2, TC3) in Tung Chung Bay and one
zone in San Tau (labeled as ST) (Figure 2.1 of Appendix O).
The horizontal length of sampling zones TC1, TC2,
TC3 and ST were about 250 m, 300 m, 300 m and 250 m, respectively. Survey of horseshoe crabs, seagrass beds and intertidal communities were
conducted in every sampling zone. The present survey was conducted in September
2016 (totally 6 sampling days between 1st and 18th
September 2016).
Horseshoe
Crabs
3.6.7
Active search method was conducted for horseshoe
crab monitoring by two experienced surveyors at every sampling zone. During the
search period, any accessible and potential area would be investigated for any
horseshoe crab individuals within 2-3 hours of low tide period (tidal level
below 1.2 m above Chart Datum (C.D.)). Once a horseshoe crab individual was
found, the species was identified referencing to Li (2008). The prosomal width,
inhabiting substratum and respective GPS coordinate were recorded. A
photographic record was taken for future investigation. Any grouping behavior
of individuals, if found, was recorded. The horseshoe crab surveys were
conducted on 1st (for TC3 and ST), 3rd (for TC1) and 18th
(for TC2) September 2016. The weather was generally cloudy with intermittent
rains on 1st and 3rd September. It was sunny and hot on
18th September 2016.
Seagrass Beds
3.6.8 Active
search method was conducted for seagrass bed monitoring by two experienced
surveyors at 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 1st (for TC3 and ST), 3rd (for
TC1) and 18th (for TC2) September 2016. The weather was generally
cloudy with intermittent rains on 1st and 3rd September.
It was sunny and hot on 18th September 2016.
Intertidal Soft Shore
Communities
3.6.9 The
intertidal soft shore community surveys were conducted on 3rd (for
TC1), 4th (for ST), 17th (for TC3) and 18th
(for TC2) September 2016. In every sampling zone, three 100 m horizontal
transect lines were laid at high tidal level (H: 2.0 m above C.D.), mid tidal
level (M: 1.5 m above C.D.) and low tidal level (L: 1.0 m above C.D.). Along
every horizontal transect line, ten random quadrats (0.5 m x 0.5m) were placed.
3.6.10
Inside
a quadrat, any visible
epifauna were collected and were in-situ identified to the lowest
practical taxonomical resolution. Whenever possible a
hand core sample (10 cm internal diameter ´
20 cm depth) of sediments was collected in the quadrat. The core sample was gently washed through a
sieve of mesh size 2.0 mm
in-situ. Any visible infauna were collected
and identified. Finally the top 5 cm surface sediments were
dug for visible infauna in the quadrat regardless of hand core sample was taken.
3.6.11
All collected fauna were released after
recording except some tiny individuals that are too small to be
identified on site. These tiny individuals were taken
to laboratory for identification under dissecting microscope.
3.6.12
The taxonomic classification was conducted in
accordance to the following references: Polychaetes: Fauchald (1977), Yang and Sun (1988); Arthropods:
Dai and Yang (1991), Dong (1991); Mollusks: Chan and Caley (2003), Qi (2004).
Data
Analysis
3.6.13 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
3.6.14
In the present survey, two species of horseshoe
crab Carcinoscorpius rotundicauda
(total 227 ind.) and Tachypleus tridentatus (total 37 ind.) were recorded. For one sight record, grouping
of 2-28 individuals was observed at same locations with similar substratum
(fine sand or soft mud). Photo records were shown in Figure 3.1 of Appendix O while
the complete records of horseshoe crab were shown in Annex II of
Appendix O.
3.6.15
Table 3.1
of Appendix O summarizes the survey results of horseshoe crab in
present survey. For Carcinoscorpius
rotundicauda, there were 36, 1, 64 and 126 individuals in TC1, TC2, TC3 and
ST respectively. For ST, the search
record was the highest (21.0 ind. hr-1 person-1) while the average body size was 33.96 mm
(prosomal width ranged 14.58-72.34 mm). TC3 had the second high search record (10.7 ind. hr-1 person-1) with average body size 30.32 mm (prosomal
width ranged 14.96-64.01 mm). For TC1, there was less number of individual but the search record (9.0 ind. hr-1
person-1) was comparable to
TC3 with less average body size 26.84 mm (prosomal width ranged 10.93-64.75mm).
For TC2, there was only one individual (prosomal width: 41.39 mm) hence the search record was very low (0.3 ind.
hr-1 person-1).
3.6.16
For Tachypleus tridentatus, there were 17 and 20 individuals in TC3 and
ST respectively. For ST, the search
record was 3.3 ind. hr-1 person-1 while the average body size was 35.69 mm
(prosomal width ranged 27.19-72.55 mm). For TC3, the search record was
2.8 ind. hr-1 person-1 while the average body size was 51.88 mm (prosomal width ranged
34.75-79.18 mm).
3.6.17
In the
previous survey of March 2015, there was one important finding that a mating
pair of Carcinoscorpius rotundicauda was found in ST (prosomal width: male 155.1 mm,
female 138.2 mm) (Figure
3.2 of Appendix O).
It indicated the importance of ST as a breeding ground of horseshoe crab.
Moreover, two moults of Carcinoscorpius
rotundicauda
were found in TC1 with similar prosomal width 130-140 mm (Figure 3.2 of Appendix O). It reflected that a certain numbers of
moderately sized individuals inhabited the sub-tidal habitat of Tung Chung Wan
after its nursery period on soft shore. These individuals might move onto soft
shore during high tide for foraging, moulting and breeding. Then it would
return to sub-tidal habitat during ebb tide. Because the mating pair should be
inhabiting sub-tidal habitat in most of the time. The record was excluded from
the data analysis to avoid mixing up with juvenile population living on soft
shore. In another previous survey of Jun. 2016, the records of the two big
individuals of Carcinoscorpius
rotundicauda (prosomal width 117.37 mm and 178.17 mm) in TC1 were excluded
from data analysis according to the same principle.
3.6.18
No marked individual of horseshoe
crab was recorded in
present survey. Some marked individuals were found in
previous surveys conducted in September 2013, March 2014
and September 2014. All
of them were released through a
conservation programme conducted by Prof. Paul Shin (Department of Biology and Chemistry, The City University
of Hong Kong (CityU)). It was a re-introduction trial
of artificial
bred horseshoe crab juvenile at selected sites. So that the horseshoe
crabs population might be restored in the natural habitat. Through a personal
conversation with Prof. Shin, about 100 individuals were released in the
sampling zone ST on 20 June 2013. All of them were marked with color tape and
internal chip detected by specific chip sensor. There should be second round of
release between June and September 2014 since new marked individuals were found
in the survey of September 2014.
3.6.19 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
3.6.20
Figures
3.3 and 3.4 of Appendix O show
the changes of number of individuals, mean prosomal width and search record of
horseshoe crabs Carcinoscorpius rotundicauda and Tachypleus
tridentatus respectively in every sampling zone throughout the monitoring
period. In general, high to medium search records (i.e. number of individuals)
of both species were always found in ST and TC3. The search record of ST was
higher from Sep. 2012 to Jun. 2014 while it was replaced by TC3 from Sep. 2014
to Jun. 2015. The search records were similar between two sampling zones from
Sep. 2015 to Jun. 2016. In present survey, the search record of Carcinoscorpius
rotundicauda in ST was much higher than TC3. For TC1, the search record was
at low to medium level throughout the monitoring period. The change of Carcinoscorpius
rotundicauda was relatively more variable than that of Tachypleus
tridentatus. Relatively, the search record was very low in TC2 (2 ind. in
Sep. 2013; 1 ind. in Mar., Jun., Sep. 2014, Mar. and Jun. 2015; 4 ind. in Sep.
2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016). For the body size, larger
individuals of Carcinoscorpius rotundicauda were usually found in ST and
TC1 relative to those in TC3. For Tachypleus tridentatus, larger
individuals were usually found in ST followed by TC3 and TC1.
3.6.21 Throughout
the monitoring conducted, it was obvious that TC3 and ST (western shore of Tung
Chung Wan) was an important nursery ground for horseshoe crab especially newly
hatched individuals due to larger area of suitable substratum (fine sand or
soft mud) and less human disturbance (far from urban district). Relatively,
other sampling zones were not a suitable nursery ground especially TC2.
Possible factors were less area of suitable substratum (especially TC1) and
higher human disturbance (TC1 and TC2: close to urban district and easily
accessible). In TC2, large daily salinity fluctuation was a possible factor
either since it was flushed by two rivers under tidal inundation. The individuals
inhabiting TC1 and TC2 were confined in small foraging area due to limited area
of suitable substrata.
Seasonal variation of horseshoe crab
population
3.6.22 Throughout the monitoring period conducted,
the search record of horseshoe crab declined obviously during dry season
especially December (Figures
3.3 and 3.4 of Appendix
O).
In December 2013, no individual of horseshoe crab was found.
In December 2014, 2 individuals of Carcinoscorpius rotundicauda
and 8 individuals of Tachypleus
tridentatus were found only. In December 2015, 2 individuals of Carcinoscorpius
rotundicauda, 6 individuals of Tachypleus tridentatus
and one newly hatched, unidentified individual were found only. The horseshoe crabs were inactive
and burrowed in the sediments during cold weather (<15 ºC).
Similar results of low search record in dry season were reported in a previous
territory-wide survey of horseshoe crab. For example, the search records in Tung
Chung Wan were 0.17 ind. hr-1 person-1 and 0.00 ind. hr-1 person-1 in wet season and dry season respectively
(details see Li, 2008). After the dry season, the search record increased with
the warmer climate.
3.6.23 From September 2012 to December 2013, Carcinoscorpius rotundicauda was a 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. Since 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.
From March 2014 to September 2015, more individuals were recorded due to larger
size and higher activity (i.e. more conspicuous walking trail).
3.6.24 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
Mar. and Jun. 2014 followed by a rapid decline in Sep. 2014. Then the number of
individuals fluctuated slightly in TC3 and ST until Sep. 2016 (present survey).
Apart from natural mortality, migration from nursery soft shore to subtidal
habitat was another possible cause. Since the mean prosomal width of Tachypleus
tridentatus continued to grow and reached about 50 mm since Mar. 2014. Then
it varied slightly between 35-65 mm from Sep. 2014 to Jun. 2016 (present
survey). Most of the individuals might have reached a suitable size strong
enough to forage in sub-tidal habitat.
3.6.25 Since TC3 and ST were regarded as important
nursery ground for horseshoe crab, 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
3.6.26 Figure 3.5 of Appendix O shows the changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus tridentatus in
TC3. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec.
2013 hence the data were lacking. In Mar 2014, the major size (50% of individual records
between upper and lower quartile) ranged 40-60 mm while only few individuals
were found. From Mar. 2014 to Sep. 2016 (present survey), the size of major
population decreased and more small individuals were recorded after Mar. of
every year. It indicated new rounds of successful breeding and spawning
of Carcinoscorpius rotundicauda in
TC3. It matched with the previous mating record in ST in Mar. 2015. Focused on
much larger sized individuals (circle dots above the box in the box plots), the size range was
quite variable (prosmal width 60-90 mm) along the sampling month. It was yet to
determine their size of migrating to sub-tidal habitat in TC3.
3.6.27 For Tachypleus tridentatus, the major
size ranged 20-50 mm while the number of individuals fluctuated from Sep. 2012
to Jun. 2014. Then a slight but consistent growing trend was observed from Sep.
2014 to Jun. 2015. The prosomal width increased from 25-35 mm to 35-65 mm. As
mentioned, the large individuals might have reached a suitable size for
migrating from the nursery soft shore to subtidal habitat. It accounted for the
declined population in TC3. From Mar. to Sep. 2016 (present survey), slight
increasing trend of major size was noticed again. Across the monitoring period,
the maximum prosomal width of major population ranged 60-70 mm. It reflected
individuals reaching this size would gradually migrate to sub-tidal habitats.
Box plot of horseshoe crab populations in ST
3.6.28
Figure
3.6 of Appendix O shows
the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius rotundicauda
was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking.
From Mar. 2014 to Sep. 2016, the
size of major population decreased and more small individuals (i.e. circle dots
below the box in the box plots) were recorded after Jun. of every year. It
indicated new round of successful spawning in ST. It matched with the previous
mating record in ST in Mar. 2015. Across the whole monitoring period, the
maximum prosomal width (i.e.
circle dots above the box in the box plots) usually ranged 70-80 mm. It
reflected individuals reaching this size would gradually migrate to sub-tidal
habitats.
3.6.29
For
Tachypleus tridentatus, a consistent growing trend was observed for
the major population from Dec. 2012 to Dec. 2014 regardless of change of search
record. The prosomal width increased from 15-30 mm to 55-70 mm. As mentioned,
the large individuals might have reached a suitable size for migrating
from the nursery soft shore to subtidal habitat. From Mar. to Sep. 2015, the
size of major population decreased slightly to a prosomal width 40-60 mm. At
the same time, the number of individuals decreased gradually. It further
indicated some of large individuals might have migrated to sub-tidal habitat,
leaving the smaller individuals on shore. There was an overall growth trend. In
Dec. 2015, two big individuals (prosomal width 89.27 mm and 98.89 mm) were
recorded only while it could not represent the major population. From Dec. 2015
to Mar. 2016, the number of individual was very few in ST that no boxplot could
be produced. In Jun. 2016, the prosomal width of major population ranged 50-70
mm. But it dropped clearly to 30-40 mm in Sep. 2016 (present survey). Based on
increasing number of small individuals recorded in Jun. and Sep. 2016, it
indicated new round of successful spawning in ST. Aross the monitoring period,
the maximum prosomal width of major population ranged 60-70 mm. It reflected
individuals reaching this size would gradually migrate to sub-tidal habitats,
similar to the finding in TC3.
3.6.30
As a summary for horseshoe crab populations in TC3 and
ST, there was successful spawning of Carcinoscorpius rotundicauda from 2014 to
2016 while the spawning time should be in spring. There were consistent,
increasing trends of population size in these two sampling zones. For
Tachypleus tridentatus, small individuals were rarely found in TC3 and ST from
2014 to 2015. It was believed no occurrence of successful spawning. The
existing individuals (that recorded since 2012) grew to a mature size and
migrated to sub-tidal habitat. Hence the number of individuals decreased
gradually. In 2016, new round of successful spawning was recorded in ST while
increased number of individuals was noticed.
Impact of the HKLR project
3.6.31
The present survey was the 16th survey
of the EM&A programme during the construction period. Based on the results,
impact of the HKLR project could not be detected on horseshoe crabs. The
population change was mainly determined by seasonal variation. In case,
abnormal phenomenon (e.g. very few numbers of horseshoe crab individuals in wet
season, large number of dead individuals on the shore) is found, it would be
reported as soon as possible.
Seagrass
Beds
3.6.32
In the
present survey, seagrass
species Halophila ovalis and Zostera japonica were recorded in ST only. Photo
records were shown in Figure 3.7 of
Appendix O while the complete records of seagrass beds survey were
shown in Annex III of Appendix
O.
3.6.33
Table 3.2 of Appendix O summarizes the results of seagrass beds survey in ST. Eight patches of Halophila
ovalis were found while the total
seagrass bed area was about 24245.1 m2. The seagrass bed area was
highly variable among patches. In the soft mud area at 0.5-1.5 m above C.D.,
the largest patch was a horizontal strand with seagrass bed area ~21446.9 m2
and variable coverage 30-80%. It had covered significant portion of the
mud flat area in ST. At vicinity, there were another large patch (total area
~2007 m2, coverage 10-80%) and two smaller, irregular patches (total
area 14.8-341.0 m2, coverage 80%). These seagrass patches had been
recorded in previous survey in Jun. 2016 but it had extended to larger area. It
reflected a new round of colonization since Mar.2016.
3.6.34
At higher tidal
level (2.0 m above C.D.), there were few seagrass patches in the sandy area
nearby the seaward mangrove boundary. There was a medium, horizontal strand
(total area ~401.3 m2, coverage ~70%) and two small patches (total
area ~3.0-8.3 m2, coverage 80-85%). In addition, there was a medium,
horizontal strand (total area ~22.8 m2) coexisting with another
seagrass species Zostera japonica of highly variable coverage (30-100%).
3.6.35
For
Zostera japonica, two
patches were found while the total
seagrass bed area was about 38.0 m2. There was one horizontal strand
coexisting with Halophila ovalis (total area ~22.8 m2,
coverage 30-50%) as mentioned. And there was a small, horizontal strand (total area ~15.2 m2, coverage
10-30%) at vicinity
3.6.36
Since majority of seagrass bed was confined
in ST, the temporal change of both seagrass species were investigated in
details.
Temporal variation
of seagrass beds
3.6.37 Figure 3.8 of Appendix
O shows the changes of estimated total area of
seagrass beds in ST along the sampling months.
For Zostera japonica, it was not recorded in the 1st and 2nd surveys
of monitoring programme. Seasonal recruitment of few, small patches (total
seagrass area: 10 m2) was found in Mar. 2013 that grew within the
large patch of seagrass Halophila ovalis.
Then the patch size increased and merged gradually with the warmer climate from
Mar. to Jun. 2013 (15 m2). However the patch size decreased and
remained similar from Sep. 2013 (4 m2) to Mar. 2014 (3 m2).
In Jun. 2014, the patch size increased obviously again (41 m2) with
warmer climate followed by a decrease between Sep. 2014 (2 m2) and
Dec. 2014 (5 m2). From Mar. to Jun. 2015, the patch size increased
sharply again (90 m2). It might be due to the disappearance of the
originally dominant seagrass Halophila
ovalis resulting in less competition for
substratum and nutrients. From Sep.2015 to Jun.2016, it was found coexisting
with seagrass Halophila ovalis
with steady increasing patch size (from 44 m2 to 115 m2) and variable coverage. In Sep. 2016, the patch size
decreased again to (38 m2) which was possibly due to the
strong competition with Halophila
ovalis.
3.6.38 For Halophila ovalis, it was recorded as 3-4
medium to large patches (area 18.9-251.7 m2; vegetation coverage
50-80%) beside the mangrove vegetation at tidal level 2 m above C.D. in Sep.
2012 (first survey). The total
seagrass bed area grew steadily from 332.3 m2 in Sep. 2012 to 727.4
m2 in Dec. 2013. Flowers were observed in the largest patch during its
flowering period. In Mar. 2014, 31
small to medium patches were newly recorded (variable area 1-72 m2
per patch, vegetation coverage 40-80% per patch) in lower tidal zone between
1.0 and 1.5 m above C.D. The total seagrass area increased further to 1350 m2.
In Jun. 2014, these small and medium patches grew and extended to each other.
These patches were no longer distinguishable and were covering a significant
mudflat area of ST. It was generally grouped into 4 large patches (1116 ¡V 2443
m2) of seagrass beds characterized of patchy distribution, variable
vegetable coverage (40-80%) and smaller leaves. The total seagrass bed area
increased sharply to 7629 m2. In Sep. 2014, the total seagrass area
declined sharply to 1111 m2. There were only 3-4 small to large
patches (6-253 m2) at high tidal level and 1 patch at low tidal
level (786 m2). Typhoon or strong water current was a
possible cause (Fong, 1998). In Sep.
2014, there were two tropical cyclone records in Hong Kong (7th-8th
Sep.: no cyclone name, maximum signal number 1; 14th-17th
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.
3.6.39
In December 2014, all the seagrass patches of
Halophila ovalis disappeared in ST.
Figure 3.9 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 can colonize
areas in short period but disappears quickly under unfavourable conditions
(Fong, 1998).
Unfavourable
conditions to seagrass Halophila ovalis
3.6.40 Typhoon or
strong water current was suggested as one unfavourable condition to Halophila ovalis (Fong, 1998). As mentioned above, there were two tropical cyclone
records in Hong Kong in September 2014. The strong water current caused by the
cyclones might have given damage to the seagrass beds.
3.6.41 Prolonged
light deprivation due to turbid water would be another unfavourable condition.
Previous studies reported that Halophila
ovalis had
little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999). Hence the seagrass bed of this species was
susceptible to temporary light deprivation events such as flooding river runoff
(Longstaff and Dennison,
1999).
3.6.42 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
at 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, were carried out within
silt curtain as recommended in the EIA report. Moreover there was no leakage of
turbid water, abnormity or malpractice recorded during water sampling. In
general, the exceedance of suspended solids concentration was considered to be
attributed to other external factors, rather than the contract works.
3.6.43 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 the mudflat of ST through
seed reproduction as long as there was no unfavourable condition in the coming
months.
Recolonization of
seagrass beds
3.6.44 Figure 3.9 of Appendix O shows the recolonization of seagrass bed area
in ST from December 2014 to September 2016 (present survey). From March
to June 2015, 2-3 small patches of Halophila
ovalis were newly found coinhabiting with another seagrass species Zostera japonica. But its total patch area was
still very low relative to the previous records. The recolonization rate was
low while cold weather and insufficient sunlight were possible factors between
December 2014 and March 2015. Moreover, it would need to compete with seagrass Zostera japonica for substratum and nutrient.
Since Zostera japonica had extended and had covered the original
seagrass bed of Halophila ovalis at
certain degree. From 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 Zostera japonica. In Jun. 2016, the total seagrass area
increased sharply to 4707.3 m2. Similar to the
previous records of March to June 2014, the original patch area increased further
to a horizontally long strand. Another large seagrass beds colonized the lower tidal zone (1.0-1.5 m
above C.D.). In September 2016 (present survey), this patch extended much and
covered significant soft mud area of ST, resulting in sharp increase of total
area (24245 m2). It indicated the second extensive colonization of
this r-strategy seagrass.
However it was not appropriate to predict a rapid decline of seagrass area in
the coming sampling months based on the previous results in December 2014.
Impact of the HKLR project
3.6.45
The present survey was the 16th survey of the
EM&A programme during the construction period. According to the results of
present survey, there was clear recolonization of both seagrass species Halophila
ovalis and Zostera japonica
in ST. Hence the negative impact of HKLR project on the seagrass was not
significant. In case, adverse phenomenon (e.g. reduction of seagrass
patch size, abnormal change of leave colour) is observed again, it would be
reported as soon as possible.
Intertidal Soft Shore Communities
3.6.46
Table 3.3 and Figure 3.10 of Appendix
O show the types of substratum along the
horizontal transect at every tidal level in every sampling zone. The relative
distribution of different substrata was estimated by categorizing
the substratum types (Gravels & Boulders / Sands / Soft mud) of
the ten random quadrats along the horizontal transect. The
distribution of substratum types varied among tidal levels and sampling
zones:
¡P In TC1, the major substratum type was
¡¥Gravels and Boulders¡¦ (60%) followed by 'Sands' (40%) at high tidal level.
High percentage of ¡¥Gravels and Boulders¡¦(90%) was recorded at the mid and low
tidal levels.
¡P In TC2, the major substrata types were ¡¥Sands¡¦
(50-60%) and ¡¥Soft mud¡¦ (30-50%) at the high and mid tidal levels. 'Soft mud'
was the major substratum type (90%) at the low tidal level.
¡P In TC3, ¡¥Sands¡¦ was the substratum type at
the high and mid tidal levels (100%). At low tidal level, ¡¥Gravels and
Boulders¡¦ (70%) was mainly recorded followed by ¡¥Soft mud¡¦ (20%).
¡P In ST, high percentage of ¡¥Gravels and
Boulders¡¦ (90-100%) was recorded at high and mid tidal levels. The major
substrata types were ¡¥Gravels and Boulders¡¦ (50%) and ¡¥Soft mud¡¦ (30%) at the
low tidal level.
3.6.47
There was neither consistent
vertical nor horizontal zonation pattern of substratum
type in all sampling zones. Such heterogeneous variation should be
caused by different hydrology (e.g. wave in different direction and intensity)
received by the four sampling zones.
3.6.48
Table 3.4 of Appendix O lists the total
abundance, density and number of taxon of
every phylum in this survey. A total of
17563 individuals were recorded. Mollusca was
significantly the most abundant phylum (total individuals 16848,
density 562 ind. m-2, relative abundance 95.9%). The
second and third abundant phya were Arthropoda
(523 ind., 17 ind. m-2, 3.0%)
and Annelida (94 ind., 3
ind. m-2, 0.5%) respectively. Relatively other phyla
were very low in abundances (density
£1 ind. m-2,
relative abundance £0.2%).
Moreover, the most diverse phylum was Mollusca
(37 taxa) followed by Arthropoda
(15 taxa) and Annelida (11 taxa). There were 1-2 taxa
recorded only for other phyla. The taxonomic resolution
and complete list of collected specimens are shown in Annex IV and V of Appendix O respectively.
3.6.49
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 (3376-6509 ind.)
varied among the four sampling zones while the phyla distributions were
similar. In general, Mollusca was the most dominant phylum (no. of individuals:
3229-6283 ind.; relative abundance 93.4-97.3%; density 431-838 ind. m-2).
Other phyla were significantly lower in number of individuals. Arthropoda was
the second abundant phylum (84-174 ind.; 2.0-4.4%; 11-23 ind. m-2).
Annelida was the third abundant phylum in TC2 and TC3 (38-52 ind.; 0.6-1.5%;
5-7 ind. m-2). Cnidaria (sea anemone) was the third abundant phylum
(25 ind.; 0.7%; 3 ind. m-2) in ST. Relatively other phyla were low
in abundance in all sampling zones (≤ 0.5%).
Dominant
species in every sampling zone
3.6.50 Table 3.6 of Appendix O lists
the abundant species (relative abundance >10%) in
every sampling zone. In TC1, the abundant species were
different between tidal levels. Gastropod Batillaria multiformis was the most abundant species of very high
density (306 ind. m-2, relative abundance 50%) at the high tidal
level (major substratum: ¡¥Gravels and Boulders¡¦) followed by gastropods Cerithidea
cingulata (123 ind. m-2, 20%) and Cerithidea djadjariensis (91
ind. m-2, 15%). At the mid tidal level (major substratum: ¡¥Gravels
and Boulders¡¦), gastropods Batillaria multiformis (144 ind. m-2,
26%), Monodonta labio (122 ind. m-2, 22%), Cerithidea
cingulata (80 ind. m-2, 15%) and rock oyster Saccostrea
cucullata (86 ind. m-2, 16%, attached on boulders) were abundant
species of low-moderate densities. At the low tidal level (major substratum:
¡¥Gravels and Boulders¡¦), gastropod Monodonta labio (159 ind. m-2,
32%) and rock oyster Saccostrea cucullata (114 ind. m-2, 23%)
were the abundant species of moderate densities.
3.6.51 At TC2, the abundant species were
different between tidal levels. Gastropods Cerithidea cingulata (336 ind. m-2, 44%) and Cerithidea
djadjariensis (272 ind. m-2, 35%) were abundant at high
density at the high tidal level (major
substrata: 'Sands' and ¡¥Soft mud¡¦). At the mid tidal level (major substratum:
¡¥Sands¡¦), gastropods Batillaria zonalis (124 ind. m-2, 29%)
and Cerithidea cingulata (107 ind. m-2, 25%) were abundant at
moderate density. The third abundant gastropod Cerithidea djadjariensis (58
ind. m-2, 14%) was at low-moderate density. At the low tidal level (major
substratum: ¡¥Soft mud¡¦), no single species was clearly abundant. Gastropods Batillaria
zonalis (74 ind. m-2, 36%), Cerithidea djadjariensis (23
ind. m-2, 11%), Cerithidea cingulata (22 ind. m-2,
11%), barnacle Balanus amphitrite (27 ind. m-2, 13%) and rock oyster Saccostrea cucullata (24
ind. m-2, 12%) were the common species at low densities.
3.6.52 At TC3, gastropod Batillaria multiformis
(452 ind. m-2, 46%) was the most abundant clearly at the high tidal
level (major substratum: ¡¥Sands¡¦). Other abundant gastropods Cerithidea
djadjariensis (279 ind. m-2, 29%) and Cerithidea cingulata (198
ind. m-2, 20%) were at moderate densities. At the mid tidal level
(major substratum: ¡¥Sands¡¦), gastropods Cerithidea cingulata (327 ind. m-2,
35%), Cerithidea djadjariensis (234 ind. m-2, 25%) and Batillaria
multiformis (228 ind. m-2, 24%) were the abundant species at
moderate-high densities. At the low tidal level (major substratum: ¡¥Gravels and
Boulders¡¦), the abundant species were at moderate densities including rock
oyster Saccostrea cucullata (291 ind. m-2, 43%, attached on
boulders) and gastropod Monodonta labio (163 ind. m-2, 24%).
3.6.53 At ST, no single species was clearly
abundant at high tidal level (major
substratum: ¡¥Gravels and Boulders¡¦). The common species included gastropods Cerithidea cingulata (78 ind. m-2, 22%), Monodonta
labio (40 ind. m-2, 11%), Lunella coronata (40 ind. m-2,
11%) and rock oyster Saccostrea cucullata (49 ind. m-2, 14%,
attached on boulders) were at low densities. At the mid tidal level (major
substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea cucullata (136
ind. m-2, 24%) and gastropod Monodonta labio (111 ind. m-2, 20%) were abundant
at moderate densities followed by gastropod Lunella coronata (60 ind. m-2,
11%). At the low tidal level (major substrata: ¡¥Gravels and Boulders¡¦ and ¡¥Soft
mud¡¦), gastropod Monodonta labio (150 ind. m-2, 35%) was the
most abundant at moderate density followed by gastropod Batillaria
multiformis (86 ind. m-2, 20%).
3.6.54
In
general, there was no consistent zonation pattern of species distribution
across all sampling zones and tidal levels. The species distribution should be
determined by the type of substratum primarily. In general, gastropods Batillaria
multiformis (total number of
individuals: 3414 ind., relative abundance 19.4%), Cerithidea cingulata (3350
ind., 19.1%), Cerithidea djadjariensis (2681 ind., 15.3%) and Batillaria
zonalis (905 ind., 5.2%) were the most commonly occurring species on sandy
and soft mud substrata. Rock oyster Saccostrea cucullata (2129 ind.,
12.1%) and gastropod Monodonta labio (2005 ind., 11.4%) were commonly
occurring species inhabiting gravel and boulders substratum.
Biodiversity and abundance of soft shore
communities
3.6.55
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. The variations among sampling zones and tidal levels were determined by the
type of substratum primarily mentioned above.
3.6.56
Among the sampling zones, the mean species number
of ST (12 spp. 0.25 m-2) were slightly higher than that of TC1, TC2
and TC3 (9-10 spp. 0.25 m-2). The mean density of TC3 (868 ind. m-2)
was clearly higher than that of TC1 (556 ind. m-2), TC2 and ST
(450-468 ind. m-2). Since the species distribution of ST was more
even relatively, the mean H¡¦ (1.9)
and J (0.8) were higher than that of
TC1, TC2 and TC3 (H': 1.3-1.5, J: 0.6-0.7).
3.6.57
Across
the tidal levels, there was no consistent difference of the mean species
number, density and J in all sampling
zones. For the mean H¡¦, there was a
slightly increasing trend from high to low tidal level in TC1, TC2 and TC3.
3.6.58
Figures 3.11 to 3.14 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. Overall no
consistent trend of any biological parameters was observed throughout the
monitoring period. All the parameters fluctuated naturally with the seasons.
Impact
of the HKLR project
3.6.59
The present survey was the 16th survey
of the EM&A programme during the construction period. Based on the results,
impacts of the HKLR project were not detected on intertidal soft shore
community. In case, abnormal phenomenon (e.g. rapid or consistent decline of
fauna densities and species number) is observed, it would be reported as soon
as possible.
3.7
Solid and Liquid Waste Management Status
3.7.1
The Contractor registered with EPD as a Chemical
Waste Producer on 12 July 2012 for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
3.7.2
The summary of waste flow table is detailed in Appendix K.
3.7.3
The Contractor was reminded that chemical waste
containers should be properly treated and stored temporarily in designated
chemical waste storage area on site in accordance with the Code of Practice on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8
Environmental Licenses and Permits
3.8.1
The valid environmental licenses and permits
during the reporting period are summarized in Appendix L.
4
Environmental Complaint and Non-compliance
4.1.1 The detailed air quality, noise, water
quality and dolphin exceedances are provided in Appendix
M.
Also, the summaries of the environmental exceedances are presented as follows:
Air Quality
4.1.2
No Limit Level exceedances of 1-hr TSP were
recorded at AMS5 during the reporting month. No Action and Limit Level
exceedances of 24-hr TSP were recorded at AMS5 during the reporting month. No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at 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 For marine water quality monitoring, no Action Level and Limit Level
exceedances of turbidity level and dissolved oxygen level was recorded during
the reporting month. An Action Level exceedance of suspended solid was recorded
at station IS10 during the reporting month. The exceedance was considered as
non-contract related. Two Limit Level exceedances of suspended solid were
recorded at stations IS10 and SR5 respectively during the reporting month.
Dolphin
4.1.5 There was one Limit Level
exceedance of dolphin monitoring for the quarterly monitoring data (between
September 2016 ¡V November 2016). According to the contractor¡¦s information, the
marine activities undertaken for HKLR03 during the quarter of September 2016 ¡V
November 2016 included piling works, removal of surcharge materials, temporary
drainage diversion, ground investigation, box culvert diversion, construction
of permanent seawall and maintenance of silt curtain.
4.1.6 There is no evidence
showing the current LL non-compliance directly related to the construction
works of HKLR03 (where the amounts of working vessels for HKLR03 have been
decreasing), although the generally increased amount of vessel traffic in NEL
during the impact phase has been partly contributed by HKLR03 works since
October 2012. It should also be noted that reclamation work under HKLR03
(adjoining the Airport Island) situates in waters which has rarely been used by
dolphins in the past, and the working vessels under HKLR03 have been travelling
from source to destination in accordance with the Marine Travel Route to
minimize impacts on Chinese White Dolphin (CWD). In addition, the contractor
will implement proactive mitigation measures such as avoiding anchoring at
Marine Department¡¦s designated anchorage site ¡V Sham Shui Kok Anchorage (near
Brothers Island) as far as practicable.
4.1.7 All dolphin protective
measures are fully and properly implemented in accordance with the EM&A
Manual. According to the Regular Marine Travel Route Plan, the travelling speed
of vessels must not exceed 5 knots when crossing the edge of the marine park.
The Contractor will continue to provide training for skippers to ensure that
their working vessels travel from source to destination to minimize impacts on
Chinese White Dolphin and avoid anchoring at Marine Department¡¦s designated
anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as far as
practicable. Also, it is recommended to complete the marine works of the
Contract as soon as possible so as to reduce the overall duration of impacts
and allow the dolphins population to recover as early as possible.
4.2
Summary of Environmental Complaint, Notification of
Summons and Successful Prosecution
4.2.1 There was one complaint received during the reporting period. The
summary of environmental complaint is presented in Table 4.1. The details of cumulative statistics of Environmental Complaints are
provided in Appendix N.
Table 4.1 A
Summary of Environmental Complaint for the Reporting Month
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaint
|
COM-2016-098
|
11 November 2016
|
Water Quality
|
4.2.2
Complaint
investigations were undertaken. The Contractor has checked the photos provided
by the complainant and confirmed that the vessel (ªø²±308) belong to Contract No. HY/2011/03. The sediment
plume generated by the vessel was likely to be caused by propeller turbulence
of the seabed mud when the vessel travelling in shallow water during low tide.
The Contractor has been reminded to schedule the vessel to move in / out of the
construction site during higher tide and minimize number of trips to avoid the
stirring up of the seabed mud when the vessel travelling in very shallow water
areas as much as practicable. Also, the Contractor was reminded to implement
environmental mitigation measures in accordance with Environmental Mitigation
Implementation Schedule (EMIS).
4.2.3
No notification of
summons and prosecution was received during the reporting period.
4.2.4 Statistics on notifications of summons and successful
prosecutions are summarized in Appendix M.
5
Comments,
Recommendations and Conclusion
5.1.1 According
to the environmental site inspections undertaken during the reporting period,
the following recommendations were provided:
¡P
The Contractor was reminded to remove the mud
inside the U-channel at N4.
The Contractor was reminded
to display a NRMM label on the mobile crane at S9.
¡P
The Contractor was reminded to maintain the
wastewater treatment facility properly at N26 and PR9.
¡P
The Contractor was reminded to remove the
accumulated mud at the seafront of S7.
¡P
The Contractor was reminded to maintain the
earth bund at the seafront of S7, S11 properly.
¡P
The Contractor was reminded to maintain the silt
curtain at Portion X, S11 and S7.
¡P
The Contractor was reminded to cover the
stockpile of sand with tarpaulin.
¡P
The Contractor was reminded to clean up the oil
stain at S11.
¡P
The Contractor was reminded to stop the leakage
of untreated runoff at S15.
¡P
The Contractor was reminded to provide a drip
tray for chemical at S15, N26, Shaft 1, S11, S7, HMA and West Portal, S16 and
Shaft 3.
¡P
The Contractor was reminded to provide the NRMM
label on the generator at S15 and N30.
¡P
The Contractor was reminded to cover the cement
mixing station at top and 3-side with impervious tarpaulin at S11 and West
Portal.
¡P
The Contractor was reminded to cover for the
stockpile of bagged cement (> 20 bags) with impervious tarpaulin at S15 and
West Portal.
¡P
The
Contractor was reminded to clear the stagnant water to avoid mosquito breeding
at HMA, N4, S7, C&C, S15, WA4, A2, S11, S8, S9, and West Portal.
¡P
The
Contractor was reminded to remove the general refuse promptly at HMA, N30,
C&C, S11, N4, S25, West Portal, S8, S7, S15 and S16.
¡P
The
Contractor was reminded to provide chemical label to all chemical containers at
HMA, S11 and S7.
¡P
The
Contractor was reminded to keep the operation of wheel washing facilities
properly at N30 and WA4.
¡P
The Contractor was reminded to inspect the
wastewater treatment facility regularly at N26 and West
Portal.
¡P
The Contractor was reminded to mark the source
of discharge on the discharge pipe at N26.
¡P
The Contractor was reminded to stop the muddy
water leakage at S11.
¡P
The Contractor was reminded to provide an
adequate wheel washing facility at N26.
¡P
The Contractor was reminded to clear the oil
stain properly at S8.
¡P
The Contractor was reminded to provide noise
barriers for tunnel excavation at S8.
¡P
The
Contractor was reminded to cover the dump truck completely at West Portal and
S15.
¡P
The
Contractor was reminded to remove the concrete waste at West Portal and Shaft
3.
¡P
The Contractor was reminded to clean up the muddy
tracks at the site exit of West Portal.
¡P
The Contractor was reminded to use impervious sheet
to cover the containers which is used for water storage at S11.
¡P
The Contractor was reminded to remove the
abandoned pipe from S15.
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 seventeenth Quarterly EM&A
Report which summarizes the monitoring results and audit findings of the
EM&A programme during the reporting period from 1 September 2016 to 30 November 2016.
Air Quality
5.3.2
No Limit Level
exceedances of 1-hr TSP were recorded at AMS5 during the reporting month. No
Action and Limit Level exceedances of 24-hr TSP were recorded at AMS5 during
the reporting month. No Action and Limit Level exceedances of 1-hr TSP and
24-hr TSP were recorded at AMS6 during the reporting month
Noise
5.3.3
No
Action/Limit Level exceedances for noise were recorded during daytime on normal
weekdays of the reporting period.
Water Quality
5.3.4
For marine water quality
monitoring, no Action Level and Limit Level exceedances of turbidity level and
dissolved oxygen level was recorded during the reporting month. An Action Level
exceedance of suspended solid was recorded at station IS10 during the reporting
month. The exceedance was considered as non-contract related. Two Limit Level
exceedances of suspended solid were recorded at stations IS10 and SR5
respectively during the reporting month.
Dolphin
5.3.5
There
was a Limit Level exceedance of dolphin monitoring for the quarterly monitoring
data between September 2016 to November 2016.
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 significantly reduced in NEL since 2012, and many individuals have shifted
away from the important habitat around the Brothers Islands.
5.3.8
It is
critical to continuously monitor the dolphin usage in North Lantau region in
the upcoming quarters, to determine whether the dolphins are continuously
affected by the various construction activities in relation to the HZMB-related
works, and whether suitable mitigation measure can be applied to revert the
situation.
Mudflat
-Sedimentation Rate
5.3.9
This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.
Mudflat - Ecology
5.3.10
The September 2016 survey was the sixteenth
survey of the EM&A programme during the construction period. Based on the
results, impacts of the HKLR project could not be detected on horseshoe crabs,
seagrass and intertidal soft shore community.
Environmental Site Inspection and Audit
5.3.11 Environmental
site inspection was carried out on 7, 14, 21 and 30 September 2016; 5,
12, 19 and 28 October 2016; and 2, 9, 16, 23 and 29 November 2016.
Recommendations on remedial actions were given to the Contractors for the
deficiencies identified during the site inspections.
5.3.12
There
was one complaint received in relation to the environmental impacts during the
reporting period. The Contractor has been reminded to schedule the vessel to
move in / out of the construction site during higher tide and minimize number
of trips to avoid the stirring up of the seabed mud when the vessel travelling
in very shallow water areas as much as practicable.
5.3.13
No notification of summons and prosecution was
received during the reporting period.