
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.6 (Dec 2013 to Feb 2014)
10 June 2014
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 Environmental Impact Assessment (EIA) Reports (Register No. AEIAR-144/2009
and AEIAR-145/2009) were prepared for the Project. The current Environmental Permit (EP)
EP-352/2009/C for HKLR and EP-353/2009/G for HKBCF were issued on 5 September
2013 and 6 August 2013, 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 Sixth Quarterly EM&A report for
the Contract which summaries the monitoring results and audit findings of the
EM&A programme during the reporting period from 1 December 2013 to 28 February
2014.
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
|
December 2013
|
January 2014
|
February 2014
|
Air
Quality
|
1-hr TSP
|
2, 6, 12, 18, 24 and 30
|
3, 9, 15, 21, 27 and 30
|
5, 7, 13, 17, 21 and 27
|
24-hr TSP
|
AMS5: 5, 20, 23 and 27
AMS6: 5, 11, 17, 23 and
27
|
AMS5: 2, 9, 14, 20 and 29
AMS6: 2, 8, 14, 20, 24
and 29
|
4, 10, 14, 20 and 26
|
Noise
|
2, 12, 18, 24 and 30
|
9, 15, 21 and 30
|
5, 14, 17 and 27
|
Water
Quality
|
2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25, 27
and 30
|
1, 3, 6, 8, 10,
13, 15, 17, 20, 22, 24, 27 and 29
|
1, 3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26 and 28
|
Chinese
White Dolphin
|
5, 9, 13 and 19
|
7, 9, 21 and 23
|
6, 12, 14 and 20
|
Mudflat
Monitoring (Ecology)
|
4, 7, 8, 18, 21 and 22
|
-
|
-
|
Mudflat
Monitoring (Sedimentation rate)
|
7
|
-
|
-
|
Site Inspection
|
4, 11, 18, 24 and 31
|
8, 15, 22 and 28
|
5, 12, 19 and 28
|
Due to inclement
weather, the dolphin monitoring was rescheduled from 17 December 2013 to 19
December 2013.
Due to interruption of electricity supply to
high volume sampler (HVS) at AMS5 during the sampling period, the 24hr- dust
monitoring result on 11 December 2013 was considered invalid. The HVS was
broken on 11 December 2013 and resumed normal on 20 December 2013. Therefore,
the air monitoring was rescheduled from 17 December 2013 to 20 December 2013.
Due to the interruption of electricity supply to high
volume sampler at AMS5 during the sampling period, the 24hr- dust monitoring
result on 8 January 2014 was considered invalid. 24 hrs dust monitoring was
rescheduled on 9 January 2014.
Due to malfunction of high volume sampler at
AMS5 on 24 January 2014, the 24 hrs dust monitoring was cancelled on 24 January
2014. After repairing the HVS, it resumed normal on 29 January 2014.
Due to unfavourable weather on 6 January 2014,
the dolphin survey was rescheduled from 6 and 8 January 2014 to 7 and 9 January
2014.
Due to the boat arrangement problem, the dolphin
monitoring was rescheduled from 20 January 2014 on 21 January 2014.
Due to Chinese New Year, the water quality
monitoring on 31 January 2014 was rescheduled to 1 February 2014.
Due to the inclement
weather on 13 February 2014, the noise monitoring was rescheduled to 14
February 2014.
As advised by the
dolphins monitoring team, the wind would be very strong on 21 February
2014. Therefore, the dolphin
monitoring was rescheduled from 21 February 2014 to 20 February 2014.
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
|
5
|
1
|
Noise
|
Leq
(30 min)
|
0
|
0
|
Water
Quality
|
Suspended
solids level (SS)
|
11
|
1
|
Turbidity
level
|
0
|
0
|
Dissolved
oxygen level (DO)
|
0
|
0
|
Dolphin
Monitoring
|
Quarterly
Analysis (December 2013 to February 2014)
|
1
|
0
|
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
A summary of environmental complaints for this
reporting period is as follows:
Environmental Complaint No.
|
Date of Complaint Received
|
Description of Environmental Complaints
|
COM-2013-045
|
27
December 2013
|
Noise
|
COM-2014-046
|
16
January 2014
|
Air
Quality
|
COM-2014-048
|
18
January 2014
|
Other -
Blackish mud
|
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.
It was found that the original monitoring
station at IS(Mf)9 (Coordinate- East 813273, North 818850) was inside the
perimeter silt curtain on 1 July 2013, as such the original impact water
quality monitoring location at IS(Mf)9 was temporarily shifted outside the silt
curtain. The new co-ordinates of station IS(Mf)9 are 813226E and 818708N since
1 July 2013.
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 Environmental Impact Assessment (EIA) Reports (Register
No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project. The current Environmental Permit (EP)
EP-352/2009/C for HKLR and EP-353/2009/G for HKBCF were issued on 5 September
2013 and 6 August 2013, 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 Sixth Quarterly Environmental Monitoring and
Audit (EM&A) report for the Contract which summaries the monitoring results
and audit findings of the EM&A programme during the reporting period from 1
December 2013
to 28 February 2014.
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
Site
Area
|
Description
of Activities
|
Portion X
|
¡P
Stone column
installation
¡P
Filling works
behind stone platform
¡P
Temporary stone
platform construction
¡P
Band drains installation
¡P
Dismantling/trimming
of temporary 40mm stone platform for construction of seawall
¡P
Piling Works
|
Portion Y
|
¡P
Access shaft
construction for SHT & HAT
¡P
Utility culvert
excavation
¡P
Pipe piling works for Depressed Roundabout
|
West Portal
|
¡P
Site formation
¡P
Slope protection/
stabilization (soil nailing works)
¡P
Pipe Roofing Installation and
Excavation of Tunnel SHT
¡P
Tree Felling
¡P
Boulder removal/ stabilization works
|
Kwo Lo Wan /Airport Road
|
¡P
Works for
diversion of Airport Road and Kwo Lo Wan Road
|
Airport Express Line
|
¡P
Pre-grouting and
pipe piling works for AEL access shafts
|
Kwo Lo Wan /Airport Road /Airport Express Line
|
¡P
Utilities
detection
¡P
Establishment of
site access
¡P
Works for east
access shaft
|
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
trigger 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 trigger
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
Contractors carried out corrective actions. 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 During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
December 2013
|
AMS5
|
83
|
22 ¡V 172
|
352
|
500
|
AMS6
|
80
|
13 ¡V 122
|
360
|
January 2014
|
AMS5
|
73
|
18 ¡V 154
|
352
|
AMS6
|
93
|
53 ¡V 284
|
360
|
February 2014
|
AMS5
|
52
|
5 ¡V 143
|
352
|
AMS6
|
63
|
36
¡V 167
|
360
|
Table 3.2 Summary
of 24-hour TSP Monitoring Results During the Reporting Period
Reporting Period
|
Monitoring
Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
|
|
|
|
|
|
December 2013
|
AMS5
|
158
|
139-195
|
164
|
260
|
AMS6
|
169
|
31-262
|
173
|
January 2014
|
AMS5
|
93
|
42-161
|
164
|
AMS6
|
142
|
86-213
|
173
|
February 2014
|
AMS5
|
64
|
51-88
|
164
|
AMS6
|
90
|
73-112
|
173
|
3.2.2 For 1-hr TSP, no Action and Limit Level exceedances were recorded for
air during daytime on normal weekdays of the
reporting period.
3.2.3 For 24-hr
TSP, an Action
Level exceedance was recorded at station AMS5 on 27 December 2013. An
Action Level exceedance of 24-hr TSP was
recorded at station AMS6 on 11, 27 December 2013, 8 and 20 January 2014. A Limit
Level exceedance of 24-hr TSP was recorded at station AMS6 on 23 December 2013.
3.2.4 The
general weather conditions at Tung Chung were foggy and haze during the dust
sampling period on 11, 23, 27 December 2013, 8 and 20 January 2014. Therefore,
it was considered that the exceedances were not related to the construction
activities of the Contract and was caused by poor weather.
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 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)
|
December 2013
|
NMS5
|
59
|
58 ¡V 61
|
When one documented complaint is received
|
75
|
January 2014
|
59
|
59 ¡V 61
|
February 2014
|
59
|
57 ¡V 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.
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, there were eleven Action Level exceedances and one Limit Level exceedance of suspended solids
level.
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 and
total number of dolphins (ANI) by the amount of survey effort for the entire
quarterly period (December 2013 - February 2014).
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
Northwest Lantau (NWL) and Northeast (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 December
2013 to February 2014, 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 869.74 km of survey effort was collected, with 93.4%
of the total survey effort being conducted under favourable weather conditions
(i.e. Beaufort Sea State 3 or below with good visibility). Among the two areas, 329.94 km and
539.80 km of survey effort were conducted in NEL and NWL survey areas
respectively.
3.5.11
The
total survey effort conducted on primary lines was 640.77 km, while the effort
on secondary lines was 228.97 km.
The slightly reduced effort on primary line was mainly due to the second
line in NEL survey area just to the east of HKBCF (i.e. line #11) being
partially blocked by the silt curtain that surrounded the HKBCF reclamation
site, and the research vessel were forced to travel around the edge of the
expanded silt curtain for that section of the transect line rather than on a
straight line. Both survey effort
conducted on primary and secondary lines were considered as on-effort survey
data. 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 December 2013 to February 2014, a total of 38 groups of
147 Chinese White Dolphins were sighted.
All except two sightings were made during on-effort search. Thirty-two on-effort sightings were made
on primary lines, while four other on-effort sightings were made on secondary
lines. During this quarterly period, only three groups of 16 dolphins were
sighted in NEL (with only one group of three dolphins sighted on primary
lines), while the other 35 groups of 131 dolphins were sighted in NWL. Summary table of the dolphin sightings
is shown in Annex II of Appendix J.
Distribution
3.5.13
Distribution of dolphin sightings made during monitoring surveys in December 2013, January and February 2014 was shown in (Figure 1 of Appendix J). Similar to previous quarterly periods, the
majority of dolphin sightings were made in the northwestern portion of the
North Lantau region. Concentration of sightings was located within the
Sha Chau and Lung Kwu Chau Marine Park, and to the west of Black Point (Figure 1 of Appendix J). On the
other hand, a few dolphin groups were sighted near Pillar Point, and near the
Brothers Islands.
3.5.14
None of the dolphin groups were
sighted in the vicinity of the HKLR03 or HKBCF reclamation site (Figure 1 of Appendix J). Only one dolphin
sighting was made near the HKLR09 alignment, while another sighting was made very
close to the reclamation site of Tuen Mun-Chek Lap Kok Link (TMCLKL) northern
landfall (Figure 1 of Appendix J).
3.5.15
Sighting distribution of the present impact
phase monitoring period (December 2013 ¡V February 2014) was compared to the one
in the baseline monitoring period (September to November 2011). During the present quarter, dolphins
rarely occurred in NEL region, which was in stark contrast to their frequent
occurrence around the Brothers Islands and in the vicinity of HKBCF reclamation
site during the baseline period (Figure
1 of Appendix J).
On the other hand, dolphin occurrence in the northwestern portion of
North Lantau region was largely similar between the baseline and impact phase
quarters, but there appeared to be fewer dolphins occurred in the middle
portion of North Lantau region where dolphins supposedly moved between their
core areas around Lung Kwu Chau and the Brothers Islands (Figure 1 of Appendix J).
3.5.16
As the baseline monitoring period was in
autumn season while the present monitoring period was in winter season, a
direct comparison in dolphin distribution between the two quarterly periods of
winter months in 2012-13 and 2013-14 was also made to avoid the potential bias
in seasonal variation. Between the
two winter periods, there were still much fewer dolphins sighted in NEL waters
as well as the middle portion of North Lantau waters during the winter months
of 2013-14 than the winter months of 2012-13 (Figure 2 of Appendix J).
In fact, both HKLR03 and HKBCF have already commenced their works since
the third and first quarters of 2013 respectively, implying that dolphin usage
has further declined in the central and eastern portion of North Lantau waters
in winter months of 2013-14 from the previous year.
Encounter
Rate
3.5.17
For the three-month study
period in December 2013, January and February 2014, 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) from each of the survey areas 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 in September to November 2011 (See Table 3.5).
Table 3.4 Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) During three Reporting
Period (Dec 2013 ¡V Feb 2014)
Survey Area
|
Dolphin Monitoring
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins from all on-effort sightings per 100 km of survey effort)
|
Primary Lines Only
|
Primary Lines Only
|
Northeast Lantau
|
Set 1 (5 & 9 Dec
2013)
|
2.68
|
8.05
|
Set 2 (13 & 19 Dec
2013)
|
0.00
|
0.00
|
Set 3 (7 & 9 Jan 2014)
|
0.00
|
0.00
|
Set 4 (21 & 23 Jan 2014)
|
0.00
|
0.00
|
Set 5 (6 & 12 Feb 2014)
|
0.00
|
0.00
|
Set 6 (14 & 20 Feb 2014)
|
0.00
|
0.00
|
Northwest Lantau
|
Set 1 (5 & 9 Dec
2013)
|
6.95
|
30.57
|
Set 2 (13 & 19 Dec
2013)
|
6.82
|
27.27
|
Set 3 (7 & 9 Jan 2014)
|
10.00
|
39.99
|
Set 4 (21 & 23 Jan 2014)
|
11.84
|
50.33
|
Set 5 (6 & 12 Feb 2014)
|
7.44
|
17.86
|
Set 6 (14 & 20 Feb 2014)
|
6.20
|
29.47
|
Table 3.5 Comparison
of Average Dolphin Encounter Rates between Reporting Period (Dec 2013 ¡V Feb
2014) and Baseline Monitoring Period (Sep ¡V Nov 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
|
0.45 ¡Ó 1.10
|
6.00 ¡Ó 5.05
|
1.34 ¡Ó 3.29
|
22.19 ¡Ó 26.81
|
Northwest Lantau
|
8.21 ¡Ó 2.21
|
9.85 ¡Ó 5.85
|
32.58 ¡Ó 11.21
|
44.66 ¡Ó 29.85
|
Note:
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)
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)
|
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
|
0.88 ¡Ó 1.36
|
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
|
Note:
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.
3.5.18
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 7.00 sightings and 26.77
dolphins per 100 km of survey effort respectively, while the encounter rates of
sightings (STG) and dolphins (ANI) in NEL were 0.61 sightings and 3.67 dolphins
per 100 km of survey effort respectively.
3.5.19
In NEL, the average dolphin encounter rates (both STG and ANI) in the
present three-month impact phase were only small fractions of the ones recorded
in the 3-month baseline period (reductions of 92.5% and 94.0% respectively
between the two periods; Table 3.5). Notably, dolphin occurrence in NEL in
the past five quarters have also been exceptionally low when compared to the baseline period (Table 3.6), which has prompted the
triggering of the Event and Action Plan.
In fact, the present quarter was the fifth consecutive quarter being
accessed that have triggered the Action Level under the Event and Action Plan.
3.5.20
On the other hand, the average dolphin encounter
rates (STG and ANI) in NWL during the present impact phase monitoring period
were slightly lower (reductions of 16.6% and 27.0% respectively) than the ones
recorded in the 3-month baseline period, indicating a reduced dolphin usage of
this survey area during the present construction period.
3.5.21
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).
3.5.22
For the comparison between the baseline period and the present quarter
(sixth quarter of the impact phase), the p-value for the differences in average
dolphin encounter rates of STG and ANI were 0.0774 and 0.1671
respectively. If the alpha value is
set at 0.1, significant difference was detected between the baseline and
present quarters in the dolphin encounter rates of STG, but not in the
encounter rates of ANI.
3.5.23
For the comparison between the baseline period and the cumulative
quarters in impact phase (i.e. first six quarters of the impact phase), the p-value
for the differences in average dolphin encounter rates of STG and ANI were
0.0179 and 0.0092 respectively. If
the alpha value is set at 0.1, significant differences were detected in both
the average dolphin encounter rates of STG and ANI (i.e. between the two
periods and the locations).
3.5.24
As
indicated in both dolphin distribution patterns and encounter rates, dolphin
usage has been significantly reduced in the NEL waters (especially around the
Brothers Islands and Shum Shui Kok) in the
present quarterly period, and such low occurrence has been consistently
documented in previous quarters.
This raises serious concern as the decline in dolphin usage could
possibly link to the HZMB-related construction activities in NEL waters, which
include the 150 hectares of habitat loss due to HKBCF reclamation, 23 hectares
of habitat loss due to HKLR03 reclamation, as well as the recently commenced
TMCLKL construction that involves intensive bored piling activities for the
southern viaduct and further reclamation of 16.5 hectares for the northern
landfall.
3.5.25
To
ensure the continuous usage of NEL waters by the dolphins, every possible
measure should be implemented by the contractors and relevant authorities to
minimize all disturbances to the dolphins, as a future marine park around the
Brothers Islands will be established in this important dolphin habitat as a
compensation measure for the habitat loss resulted from the HKBCF reclamation
works. Unless such declining trend
can be reverted after the establishment of the Brothers Islands
Marine Park,
there should be a presumption against further reclamation in North
Lantau waters as suggested in Hung (2013).
Group
Size
3.5.26
Group size of Chinese White
Dolphins ranged from 1-12 individuals per group in North Lantau region during
December 2013 to February 2014. 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 3.7.
Table 3.7 Comparison
of Average Dolphin Group Sizes between Reporting Period (Dec 2013 ¡V Feb 2014) and Baseline Monitoring
Period (Sep¡V Nov 2011)
|
Average Dolphin Group Size
|
Reporting Period
|
Baseline Monitoring Period
|
Overall
|
3.87 ¡Ó 2.84 (n = 38)
|
3.72 ¡Ó 3.13 (n = 66)
|
Northeast Lantau
|
5.33 ¡Ó 3.21 (n = 3)
|
3.18 ¡Ó 2.16 (n = 17)
|
Northwest Lantau
|
3.74 ¡Ó 2.82 (n = 35)
|
3.92 ¡Ó 3.40 (n = 49)
|
3.5.27
The average dolphin group sizes in the entire
North Lantau region during December 2013 to February 2014 were slightly higher
than the ones recorded in the three-month baseline period (Table 3.7).
Although the average group size in NEL was quite high during the present
monitoring period when compared to the baseline period, the sample size of the
three dolphin groups in 2013 was actually very small for such comparison.
3.5.28
Distribution of dolphins with larger group sizes
during the present quarter is shown in Figure
3 of Appendix J, with comparison to the one in baseline period.
In winter months of 2013-14, almost all larger dolphin groups were clustered at
the northwestern portion of North Lantau near Sha Chau, Lung Kwu Chau and Black
Point, with only one other larger dolphin group sighted near Siu Ho Wan in NEL (Figure 3
of Appendix J). This distribution pattern
is similar to the baseline period, except that a few more larger dolphin groups were sighted in NEL as
well as around the airport platform during the baseline period. Notably, none of the larger dolphin
groups were sighted near the HKLR03 reclamation site in the present monitoring
period (Figure 3
of Appendix J).
Habitat
Use
3.5.29
From December 2013 to February 2014, the most
heavily utilized habitats by Chinese White Dolphins mainly concentrated around
Lung Kwu Chau, to the west of Sha Chau and Black Point (Figures 4a and 4b of Appendix J).
Only two grids in NEL recorded the presence of dolphins near Siu Ho Wan
with moderately high dolphin densities.
None of the grids near HKLR03/HKBCF reclamation sites, HKLR09 or TMCLKL
alignment recorded the presence of dolphins during on-effort search in the
present quarterly period.
3.5.30
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 will be presented when more survey effort for each
grid will be collected throughout the impact phase monitoring programme.
3.5.31
When compared with the habitat use patterns
during the baseline period, dolphin usage in NEL was noticeably much lower in
the present impact monitoring period (Figure
5 of Appendix J).
During the baseline period, nine grids between Siu Mo To and Shum Shui
Kok recorded moderately high to high dolphin densities, which was in stark
contrast to the only two grids with dolphin presence during the present impact
phase period (Figure 5
of Appendix J). On the other hand, the
density patterns between the baseline and impact phase monitoring periods were
similar in NWL, except that dolphins were rarely present in the eastern portion
of this region (Figure 5
of Appendix J).
3.5.32
The absence of
dolphins in the identified important habitats around the Brothers Islands and Shum Shui Kok in consecutive quarters in
2013-14 is of serious concern. The
future Brothers Islands Marine
Park will be established
in this area upon the completion of HKBCF reclamation works, as an important
compensation measure for the associated habitat loss. It should be further examined whether
the very low usage of dolphins would be related to the on-going HZMB-related
construction works, and such diminished use would continue in this important
dolphin habitat in the upcoming quarters.
Mother-calf Pairs
3.5.33
During the three-month
study period, a total of one unspotted calf (UC) and nine unspotted juveniles
(UJ) were sighted in NEL and NWL survey areas. These young calves comprised 6.8% of all
animals sighted, which was the same percentage recorded during the baseline
monitoring period (6.8%), but slightly lower than the previous quarter.
3.5.34
All except one of
these young calves were present within and adjacent to the Sha Chau and Lung
Kwu Chau Marine Park (Figure 6 of Appendix J), and all of them were sighted within larger dolphin
groups with at least five individuals.
Notably, only one UJ was sighted near Siu Ho Wan in NEL, and none of the
young calves were sighted in the vicinity of the HKBCF/HKLR03 reclamation sites
and HKLR09/TMCLKL alignments during the present quarter (Figure 6 of Appendix J).
Activities
and Associations with Fishing Boats
3.5.35
A total of six dolphin
sightings were associated with feeding and socializing activities during the
three-month study period. The
percentage of feeding activities comprised of 7.9% of the total number of
dolphin sightings, which was lower than the one recorded during the baseline
period (11.6%). On the contrary,
the percentage of socializing activities during the present impact phase
monitoring period (7.9%) was slightly higher than the one recorded during the
baseline period (5.4%). Only one
group of dolphins was engaged in traveling activity, and the rarity of this
observed activity was similar to the baseline monitoring period and previous
impact phase monitoring periods.
3.5.36
Distribution of dolphins engaged in different
activities during the three-month study period is shown in Figure 7 of Appendix J. No
apparent concentration of sightings was found for feeding activity, but all
three sightings associated with socializing activities were located in the
waters between Black Point and Lung Kwu Chau (Figure 7 of Appendix J).
3.5.37
During the three-month period, only one of the
38 dolphin groups was found to be associated with an operating hang trawler
near the western border of Hong Kong. The extremely low level of fishing boat
association in the present and previous quarters was consistently found, and
was likely related to the recent trawl ban being implemented in 2013 in Hong Kong waters.
Photo-identification
and Individual Range Use
3.5.38
From
December 2013 to February 2014, over 3,000 digital photographs of Chinese White
Dolphins were taken during the impact phase monitoring surveys for the
photo-identification work.
3.5.39
In
total, 44 individuals sighted 86 times altogether were identified (see summary
table in Annex III of Appendix J and photographs of identified individuals in Annex IV of Appendix J). Only 13 of these 86 re-sightings were
made in NEL, which involved nine different individuals. Notably, these were the same individuals
that were repeatedly sighted before in NEL throughout the HKLR03 impact phase
monitoring surveys as well as in the baseline monitoring period
3.5.40
Most
identified individuals were sighted only once or twice during the three-month
period, with the exception of seven individuals being sighted thrice, and three
individuals (EL01, NL136 and 139) being sighted four to five times. Two individuals, NL24 and NL48, were
sighted six times on different survey days during the three-month period.
3.5.41
Notably,
four of these 44 individuals (NL33, NL226, NL296 and WL179) were also sighted
in West Lantau waters during the HKLR09
monitoring surveys during the same three-month period, showing their extensive
movement between North and West Lantau regions.
3.5.42
Six
well-recognized females were accompanied with their calves during their
re-sightings. All of these mothers
(NL33, NL93, NL98, NL123, NL202 and NL221) were frequently sighted with their
calves throughout the HKLR03 impact phase monitoring period.
3.5.43
Ranging patterns of the 44
individuals identified during the three-month study period were determined by
fixed kernel method, and are shown in Annex V of Appendix J.
3.5.44
The majority of individuals
sighted in this quarter were utilizing their range use in NWL, and only a few
individuals had their range extended to NEL survey area, especially around the
Brothers Islands (Annex V of Appendix J). This is in contrary to
the extensive movements between NEL and NWL survey areas observed in the
earlier impact monitoring quarters as well as the baseline period.
3.5.45
For many individuals that previously utilized the Brothers Islands as
their major core area of activities, they have apparently shifted their range
use away from this important habitat (e.g. CH34, NL48, NL123), while others
have greatly diminished their range use in NEL in the past quarters in 2013-14
(e.g. NL98, NL120, NL261), and further expanded their range use elsewhere in WL
waters (e.g. NL33, NL226).
3.5.46
Such
diminished or abandoned usage of NEL waters by a large number of individual
dolphins coincided well with the noticeable decline in dolphin occurrence in
NEL as discussed in Sections 3.5.13 to
3.5.25. This is of serious
concern, as the Brothers
Islands in NEL was once
identified an important habitat for many year-round residents that focused
their core area use there (Hung 2008, 2013). Therefore, the ranging pattern of
individual dolphins should be continuously monitored around Lantau waters, and
measures should be taken to ensure that dolphins will continue to move between
NWL and NEL without any hindrance as a result of the HZMB-related construction
works.
Action
Level / Limit Level Exceedance
3.5.47
There was one Action Level
exceedance of dolphin monitoring for the quarterly monitoring data (December
2013 ¡V February 2014). According
to the contractor¡¦s information, the marine activities undertaken for HKLR03
during the two quarterly periods (September to November 2013 and December 2013
to February 2014) included stone platform construction, reclamation, stone
column installation, band drain installation and excavation of stone platform,
surcharge activities, construction of seawall and geotextile tube installation
works. There is
no evidence showing the current AL non-compliance directly related to the
construction works of HKLR03. 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. In addition,
the contractor will implement proactive mitigation measures such as avoiding
anchoring at Marine Department¡¦s designated anchorage site ¡V Sham Shui Kok
Anchorage (near Brothers Island) as far as practicable.
3.5.48
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).
3.5.49
For
the comparison between the baseline period and the present quarter (sixth
quarter of the impact phase), the p-value for the differences in average
dolphin encounter rates of STG and ANI were 0.0774 and 0.1671
respectively. If the alpha value is
set at 0.1, significant difference was detected between the baseline and
present quarters in the average dolphin encounter rates of STG, but not in the
encounter rates of ANI.
3.5.50
For
the comparison between the baseline period and the cumulative quarters in
impact phase (i.e. first six quarters of the impact phase), the p-value for the
differences in average dolphin encounter rates of STG and ANI were 0.0179 and
0.0092 respectively. If the alpha
value is set at 0.1, significant difference was detected in both the average
dolphin encounter rates of STG and ANI (i.e. between the two periods and the
locations).
3.5.51
The
AFCD monitoring data during December 2013 to February 2014 has been reviewed by
the dolphin specialist, and only two groups of five dolphins
were sighted from 163.31 km of survey effort on primary lines in NEL during the
same quarter. This review has
confirmed that the very low occurrence of dolphins reported by the HKLR03
monitoring survey in winter 2013 in NEL is accurate.
3.5.52
There
is no evidence showing that the sources of impact directly related to the
construction works of HKLR03 that may have affected the dolphin usage in the
NEL region.
3.5.53
All
dolphin protective measures are fully and properly implemented in accordance
with the EM&A Manual. The Contractor will continue to provide
training to 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.
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 7 December 2013.
The mudflat surface levels at the four established monitoring stations
and the corresponding XYZ HK1980 GRID coordinates are presented in Table 3.8 and Table 3.9.
Table 3.8 Measured Mudflat Surface Level Results
|
Baseline Monitoring
(September 2012)
|
Impact Monitoring
(December 2013)
|
Monitoring Station
|
Easting (m)
|
Northing (m)
|
Surface Level
|
Easting (m)
|
Northing (m)
|
Surface Level
|
(mPD)
|
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.160
|
816678.729
|
1.027
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.247
|
815831.552
|
0.942
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.612
|
815953.327
|
1.432
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.424
|
816151.385
|
0.981
|
Table 3.9 Comparison
of measurement
|
Comparison of measurement
|
Remarks and Recommendation
|
Monitoring Station
|
Easting (m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
0.001
|
0.002
|
0.077
|
Within tolerance, no significant change
|
S2
|
-0.025
|
0.021
|
0.078
|
Within tolerance, no significant change
|
S3
|
0.027
|
0.019
|
0.091
|
Level continuously increased
|
S4
|
-0.009
|
0.004
|
0.050
|
Within tolerance, no significant change
|
3.6.2
This measurement result was generally and relatively higher than the baseline
measurement at S3. The mudflat level is continuously increased. For S1, S2 and
S4 showed that the level has increased within tolerance and their sea bed depth would not be considered as
significant change.
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 December 2013.
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 3.10 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)
|
02-Dec-13
|
7.51
|
5.95
|
11.75
|
7.27
|
5.80
|
13.00
|
04-Dec-13
|
7.32
|
11.25
|
12.90
|
7.28
|
9.60
|
12.35
|
06-Dec-13
|
7.43
|
10.85
|
16.15
|
7.18
|
12.20
|
17.50
|
09-Dec-13
|
7.16
|
8.95
|
8.45
|
7.16
|
8.80
|
9.95
|
11-Dec-13
|
7.12
|
5.20
|
6.45
|
7.30
|
11.15
|
14.25
|
13-Dec-13
|
7.31
|
4.20
|
5.70
|
7.49
|
6.90
|
9.05
|
16-Dec-13
|
7.82
|
6.95
|
12.60
|
7.16
|
5.80
|
10.80
|
18-Dec-13
|
7.50
|
11.30
|
15.00
|
7.33
|
12.75
|
16.75
|
20-Dec-13
|
7.67
|
11.05
|
17.70
|
7.53
|
11.35
|
14.90
|
23-Dec-13
|
8.01
|
11.50
|
13.60
|
7.66
|
11.35
|
13.10
|
25-Dec-13
|
7.98
|
10.50
|
10.40
|
7.96
|
7.45
|
8.20
|
27-Dec-13
|
7.89
|
4.85
|
10.55
|
8.25
|
5.40
|
16.90
|
30-Dec-13
|
8.19
|
5.10
|
4.45
|
8.58
|
5.05
|
5.10
|
Average
|
7.61
|
8.28
|
11.21
|
7.55
|
8.74
|
12.45
|
Mudflat Ecology Monitoring
Sampling
Zone
3.6.6
There are two survey areas specified under the
updated EM&A Manual for the Contract, namely Tung Chung Bay and San
Tau. Tung Chung Bay survey area is
divided into three sampling zones (TC1, TC2 and TC3) and there is one sampling
zone at San Tau (ST). Survey of
horseshoe crabs, seagrass beds and intertidal communities were conducted in
each sampling zone. The locations
of sampling zones are shown in Annex I
of Appendix O.
Horseshoe
Crabs
3.6.7
An active search method was adopted for
horseshoe crab survey at each sampling zone. The survey was undertaken by 2
specialists at each sampling zone. During the search
period, any accessible and potential area would be investigated for any
horseshoe crab individuals within 2-3 hours in low tide period (tidal level below 1.2 m above Chart Datum (C.D.)). Once a horseshoe crab was found, the
species, size and inhabiting substrate, photographic record and respective GPS
coordinate were recorded with reference to Li (2008). The horseshoe crab surveys were conducted on 4th (for zones
TC1 and TC2) and 18th (for zones TC3 and ST) December, 2013. The
weather was cloudy, windy and very cold on both survey days.
Seagrass
Beds
3.6.8
An active search method was adopted for seagrass
bed survey at each sampling zone.
The survey was undertaken by 2 specialists each spending within 2-3 hours in low tide period.
Once seagrass bed was observed, the species, the estimated area (m2),
photographic record and respective GPS coordinate were recorded. The seagrass
bed surveys were conducted on 4th (for zones TC1 and TC2) and 18th
(for zones TC3 and ST) December, 2013. The weather was cloudy, windy and very
cold on both survey days.
Intertidal
Soft Shore Communities
3.6.9 The sandy
shore of San Tau and Tung Chung Bay from the uppermost part of the shore and to
the water edge was divided into three tidal zones ¡V upper, middle and lower zones, at each
sampling zone, TC1, TC2, TC3 and ST. A 100m transect was laid in each of the
three tidal zones for fauna sampling.
3.6.10
At each sampling
zone, three 100m horizontal transects were laid at 2.0m, 1.5m and
1.0m above C.D. Along each
transect, ten random quadrats (0.5 m x 0.5m) were placed. In each quadrat, the epifauna and
infauna (within the top 5cm sediment) in each quadrat were identified and their
numbers/coverage percentages were recorded. One core of 10cm diameter x 20cm depth
was also collected within each quadrat.
The sediments of the cores were sieved with 2mm mesh-size sieve and the
biota inside was identified and counted.
All collected fauna were released after
recording except some tiny individuals that in-situ
identification was not feasible. These tiny individuals were collected and were
identified in the laboratory. Species and abundance of biota in both
cores and quadrats were reported. The intertidal soft shore community surveys were conducted in low tide
period on 7th (for ST), 8th (for TC3), 21st
(for TC2) and 22nd December 2013 (for TC1).
Data
Analysis
3.6.11
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
3.6.12
Figure
3.1 of Appendix O show the changes of number of individuals, mean prosomal width and search record of
horseshoe crab Tachypleus tridentatus at every sampling zone along the
sampling months. Across
the sampling months, the highest search record of Tachypleus tridentatus was reported at ST while the estimated age
ranged 2.6¡V8.0 years. It indicated that ST 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). In contrast, no
individual was found at TC2 except that in September 2013 (2 individuals only).
It showed that TC2 was not a nursery ground for horseshoe crab. Possible
factors were larger salinity change (flushed by two rivers) and higher human
disturbance (closest to urban district and easily accessible by people.
3.6.13 Another less common species Carcinoscorpius rotundicauda was not
found during the whole survey period except the survey conducted in December
2012 at ST (4 individuals). This species was believed present in ST at very low
number while encounter was very rare.
3.6.14
Both number of individuals and search records declined obviously during
dry season (from September to December) at TC1, TC3 and ST (Figure. 3.1 of Appendix O). As mentioned, the horseshoe crabs were inactive
and burrowed in the sediments during cold weather (<15 ºC). Similar results of low search record in dry seasons were reported in
a previous territory-wide survey of horseshoe crab. For example, the search
records at Tung Chung Wan were 0.17 individuals hr-1
person-1 and 0 individual hr-1 person-1 in wet season and dry
season respectively (details see Li, 2008). From December to September, the
search record increased along with the warmer climate at the three sampling
zones.
3.6.15
Figure 3.2 of Appendix O shows
the
changes of prosomal width of horseshoe crab Tachypleus tridentatus at the important
nursery ground ST. It was believed that most of individuals (50% records
between upper and lower quartile), recorded in the dry season, had grown to a
size of double in June 2013 (prosomal width increase from 10-20 mm to 30-50
mm). The individuals remained similar in size in September 2013. It indicated the major moulting period
occurring between March and June. At the same time, tiny individuals (10-15 mm)
were found (outliers of low value) and seasonal spawning was
believed occurring there.
3.6.16
At
ST, sharp increase of number of individuals was recorded from 15 individuals in
March 2013 and 59 individuals in June 2013 to 94 individuals in September 2013). A personal conversation was conducted with Prof.
K.S. Shin (Department of Biology and Chemistry, The City University of Hong
Kong (CityU)) who was running a conservation programme of horseshoe crab in Hong
Kong. His monitoring team recorded similar increase of horseshoe crab
population during the wet season of this year. It was believed the suitable ambient temperature increased
its conspicuousness.
3.6.17
Besides,
18 labeled individuals of Tachypleus tridentatus (prosomal width:
28.76-56.00 mm) were recorded in the survey of September 2013. All of them were
released through a conservation programme conducted by Dr. Shin (CityU). It was
a re-introduction trial of artificial bred and marked horseshoe crab juvenile
at selected sites. So that the horseshoe crabs population might be restored in
the natural habitat. Through a personal conversation with Dr Shin, about 100
individuals were released to ST on 20 June 2013. All these labeled individuals
were not included in the results of present monitoring programme.
3.6.18
The
present survey was the fifth sampling event 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
considering the factor of natural, seasonal variation, If abnormal phenomenon (e.g. very few
numbers of horseshoe individuals in warm weather) is observed, it would be
reported as soon as possible.
Seagrass
Beds
3.6.19 Table 3.1 and Figure 3.3 of Appendix O show the
records of seagrass beds survey at every sampling zone. Seagrass was recorded in ST only while the most obvious patch was a long strand of Halophila ovalis nearby the mangrove vegetation on sandy substratum at tidal level 2m
above C.D.. The estimated total
area was 633.6 m2 with vegetation
coverage 90-100%. It was formed by three patches of
dense seagrass close to each other. Based on previous surveys, these three
patches had grown and merged as one from September 12 to June 13. In present survey, these
three patches had slightly separated. Beside, flowers were observed that
indicated the reproductive period of H. ovalis (Figure 3.4 of Appendix O).
3.6.20 Moreover, 15 small patches of H. ovalis were recorded on soft
mud at tidal level between 1.0 m and 1.5 m above C.D.. The estimated area of
each patch varied highly and ranged 1.0-33.9 m2 with estimated
coverage ranging 5-80%. Six of the small patches were recorded in Sep. survey
while more patches were recorded in the present survey. Seasonal recruitment of
H. ovalis was believed occurred between June and December.
3.6.21 One small patch of Zostera japonica was found within the long strand of Halophila
ovalis. The estimated area was
5.4 m2 while
the estimated coverage was about 20-30%.
3.6.22 Figure 3.5 of Appendix O shows the changes of
estimated total area of seagrass beds at ST along the sampling months. For seagrass
Halophila ovalis, the total area and estimated coverage increased
gradually. It showed that the seagrass was in scattered patches during dry
season then grew and merged into single patch during wet season. Seasonal
recruitment during wet season further increased the total area of seagrass.
However it was doubt that the newly recruited patches of seagrass would survive
the natural heat stress, predation and wave action in the next wet season.
3.6.23 For seagrass Zostera japonica, it was not reported in the
surveys of September and December 2012. Seasonal recruitment of few patches was
reported between December and March. Then the patch size increased and merged
gradually with the warmer climate. However the patch size decreased sharply in
September survey. The patch might not overcome the high heat stress exerted on
shore between June and September 2013. The patch size increased slightly in the
present survey along with the cooler dry season.
3.6.24 The present survey was the fifth
time of sampling of the EM&A programme during the construction period.
Based on the results, impacts of the HKLR project could not be detected on
seagrass. The seagrass area of Halophila
ovalis was increasing steadily due to natural growth and seasonal
recruitment. Although that of Zostera
japonica decreased in the September survey, it would be the cause of
natural heat stress. In case, abnormal phenomenon (e.g. rapid reduction of
seagrass patch size) was observed, it would be reported as soon as possible.
Intertidal
Soft Shore Communities
3.6.25
Table 3.2 and Figure 3.6 of Appendix O show the
types of substratum along the horizontal transect at every tidal level of every
sampling zone. The relative distribution of different substrata was estimated
by investigating the substratum types (Gravels & Boulders / Sands / Soft
mud) of the ten random quadrats along the horizontal transect.
3.6.26
The distribution of substratum
types varied among tidal levels and sampling zones. At TC1, higher percentage
of ¡¥Sands¡¦ (50%) and ¡¥Gravels and Boulders¡¦ (40%) were recorded at high tidal
level.High percentage of ¡¥Gravels and Boulders¡¦ (90%) was recorded at mid tidal level. Higher
percentages of ¡¥Sands¡¦ (50%) and ¡¥Soft mud¡¦ (30%) were
recorded at low tidal level. At TC2, high
percentage of ¡¥Sands¡¦ (80%) was recorded while the rest was ¡¥Soft
mud¡¦ (20%) at high tidal level. Higher percentages of ¡¥Sands¡¦ (60%) and
¡¥Gravels and Boulders¡¦