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/H
for HKBCF were issued on 22 December 2014 and 19 January 2015, respectively.
These documents are available through the EIA Ordinance Register. The
construction phaseof 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 tenth 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 2014to 28
February 2015.
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:
Due to malfunction of HVS at AMS5 on 28 November
2014, the 24-hr TSP monitoring undertaken at AMS5 was less than 24 hours and the result was therefore considered invalid. The 24-hr TSP monitoring
was rescheduled from 28 November 2014 to 2 December 2014. The
monitoring result for
2 December 2014 is provided in this report.
Due to power interruption of HVS at station AMS5,
the 24-hr TSP monitoring at station AMS5 was rescheduled from 4 December 2014 to 5 December 2014.
Due to malfunction of HVS at station AMS5, the
24-hr TSP monitoring at station AMS5 on 10 December 2014 was cancelled. The 24-hr TSP
monitoring at station AMS5 was rescheduled to 17
December 2014 after repairing the HVS.
Due to the change of tide pattern and weather condition, mudflat
monitoring (ecology) was rescheduled from 20 December 2014 to 10 December 2014.
Due to bad weather condition on 12 January 2015,
the noise monitoring at station NMS5 was rescheduled from 12 January 2015 to 16 January 2015.
Due to boat availability issue, the dolphins
monitoring was rescheduled from 3 December 2014 to 2 December 2014, 22 December
2014 to 23 December 2014, 6 January 2015 to 8 January 2015, 20 January 2015 to
29 January 2015 and 12 February 2015 to 13 February 2015.
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
3
0
Noise
Leq (30 min)
0
0
Water Quality
Suspended solids level (SS)
5
2
Turbidity level
0
0
Dissolved oxygen level (DO)
0
0
Dolphin Monitoring
Quarterly Analysis (Dec 14 to Feb 2015)
0
1
The
Environmental Team investigated all exceedances and
found that they were not project related.
All
investigation reports for exceedances of the Contract
have been submitted to ENPO/IEC for comments and/or follow up to identify
whether the exceedances occurred related to other
HZMB contracts.
Implementation of Mitigation Measures
Site
inspections were carried out on a weekly basis to monitor the implementation of
proper environmental pollution control and mitigation measures for the
Project.Potential environmental
impacts due to the construction activities were monitored and reviewed.
Complaint Log
There
were two environmental complaints received in relation to the environmental
impact during the reporting period.
A summary
of environmental complaints for this reporting period is as follows:
Environmental
Complaint No.
Date
of Complaint Received
Description
of Environmental Complaints
COM-2014-063
3 December 2014
Noise
COM-2014-065
24 December 2014
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.
1.1.1The 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).
1.1.2The 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.
1.1.3China 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/H for HKBCF were issued on 22 December
2014 and 19 January 2015, 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.
1.1.4BMT Asia Pacific Limited has been
appointed by the Contractor to implement the EM&A programme for the Contract in accordance
with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and will be
providing environmental team services to the Contract.ENVIRON Hong Kong Ltd. was
employed by HyD as the Independent Environmental
Checker (IEC) and Environmental Project Office (ENPO) for the Project. The
project organization with regard to the environmental works is provided in Appendix A.
1.1.5This is the tenth 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 2014 to 28 February 2015.
1.2.1The 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.
1.3Construction Programme
1.3.1A
copy of the Contractor’s construction programme is
provided in Appendix B.
1.4Construction
Works Undertaken During the Reporting Period
1.4.1A
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
1.1Construction
Activities during Reporting Period
Site Area
Description
of Activities
Portion X
·Dismantling/trimming of temporary 40mm
stone platform for construction of seawall
·Filling works behind stone platform
·Temporary stone platform construction
·Sheet piling
·Excavation and lateral support works for
Scenic Hill Tunnel (Cut & Cover Tunnel)
·Construction of seawall
Portion Y
·Access shaft construction for Scenic Hill
Tunnel& HKBCF to Airport Tunnel
·Utility culvert excavation
·Highway Operation and Maintenance Area
Building Foundation Works
West Portal
·Pipe roofing installation and excavation
for Scenic Hill Tunnel
·Ventilation Building Foundation Works
Airport
Express Line
·Pre-grouting and pipe piling works for
Airport Express Line access shafts
Airport
Road
·Excavation works for HKBCF to Airport
Tunnel West (Cut & Cover Tunnel)
·Pipe Piling Cofferdam Works forHKBCF to Airport Tunnel West (Cut
& Cover Tunnel)
Kwo Lo Wan /Airport Road
·Works for diversion of Airport Road and Kwo Lo Wan Road
Kwo Lo Wan /Airport Road /Airport Express Line
·Utilities detection
Kwo Lo Wan Road
·Excavation and lateral support works at
shaft 3 extension north shaft & south shaft
2.1.1The 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.
2.1.2A 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.
Three
times per week during mid-ebb and mid-flood tides (within ± 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
2.2.1Table 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)
2.2.2The Action and Limit Levels for water quality monitoring are given as in
Table 2.3.
Table 2.3Action
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.
2.2.3The Action and Limit Levels for dolphin monitoring are shown in Tables 2.4 and 2.5.
Table 2.4Action
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 2.5Derived
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.
2.3Event Action
Plans
2.3.1The Event Actions Plans for air
quality, noise, water quality and dolphin monitoring are annexed in
Appendix D.
2.4Mitigation
Measures
2.4.1Environmental mitigation measures for the contract were recommended in
the approved EIA Report.Appendix E lists the
recommended mitigation measures and the implementation status.
3Environmental Monitoring and Audit
3.1Implementation of Environmental Measures
3.1.1In response to the
site audit findings, the Contractor carried out corrective actions.Details of site audit findings and the
corrective actions during the reporting period are presented in Appendix F.
3.1.2A summary of the
Implementation Schedule of Environmental Mitigation Measures (EMIS) is
presented in Appendix E.
3.1.3Regular marine travel route for marine vessels were implemented
properly in accordance to the submitted plan and relevant records were kept
properly.
3.1.4Dolphin Watching Plan was implemented during the reporting period. No dolphins inside the silt curtain
were observed. The relevant records were kept properly.
3.2.1The 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 3.1Summary
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 2014
AMS5
140
76 - 276
352
500
AMS6
131
72 - 239
360
January 2015
AMS5
139
86 - 229
352
AMS6
136
67 - 207
360
February 2015
AMS5
180
107 -
283
352
AMS6
175
107 -
245
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
2014
AMS5
78
56-107
164
260
AMS6
130
40-218
173
January
2015
AMS5
97
56- 189
164
AMS6
123
76 - 212
173
February
2015
AMS5
81
36 - 132
164
AMS6
86
46 - 144
173
3.2.2No
Action and Limit Level exceedances of 1-hour TSP and
no Limit Level exceedance of 24-hour TSP were
recorded at AMS5 and AMS6 during the reporting period.
3.2.3An
Action Level exceedance of 24-hour TSP at AMS5 was
recorded on 21 January 2015. An Action Level exceedance of 24-hour TSP
at AMS6 was recorded on 16 December 2014 and 21 January
2015, respectively.
3.3Noise
Monitoring Results
3.3.1The 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 3.3Summary
of Construction Noise Monitoring Results During the
Reporting Period
3.4.1Impact 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.
3.4.2During the reporting
period, five
Action Level exceedances and two Limit Level exceedancesfor suspended solid level were recorded. No
exceedances
of Action and Limit
Level for
dissolved oxygen level and turbidity
were recorded.
3.4.3Water 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.
3.5.2Encounter rate analysis – 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.
3.5.3Firstly, 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).
3.5.4Secondly, 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 2014 –
February 2015).
3.5.5Quantitative grid analysis on habitat use – 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).
3.5.6The 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%
whereS
= 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
3.5.7Behavioural
analysis – 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.
3.5.9During
the period of December 2014 to February 2015, six sets of systematic
line-transect vessel surveys were conducted to cover all transect lines in NWL
and NEL survey areas twice per month.
3.5.10From
these surveys, a total of 891.50 km of survey effort was collected, with 99.6%
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,
347.05 km and 544.45 km of survey effort were conducted in NEL and NWL survey
areas respectively.
3.5.11The
total survey effort conducted on primary lines was 645.44 km, while the effort
on secondary lines was 246.06 km.Both survey effort conducted on 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.
3.5.12During
the six sets of monitoring surveys in December 2014 to February 2015, a total
of 15 groups of 52 Chinese White Dolphins were sighted.All dolphin sightings were made during
on-effort search.Twelve of the 15
on-effort sightings were made on primary lines, while the other three were made
on secondary lines.In this
quarterly period, all dolphin groups were sighted in NWL, while none of them
were sighted in NEL.A summary
table of the dolphin sightings is shown in Annex
II of Appendix J.
Distribution
3.5.13Distribution
of dolphin sightings made during monitoring surveys in December 2014 to
February 2015 is shown inFigure 1 of Appendix J. Similar to recent quarters, the majority
of dolphin sightings made in the present quarter were concentrated in the
northwestern end of the North Lantau
region, with higher concentration near the northern boundary of the survey area
and around Lung Kwu Chau (Figure 1 of Appendix J).Similar to recent quarters, the majority of dolphin sightings made in
the present quarter were concentrated in the northwestern end of the North Lantau region, with
higher concentration near the northern boundary of the survey area and around
Lung Kwu Chau.
3.5.14Notably,
all dolphin sightings were made far away from the HKLR03/HKBCF reclamation
sites or along the entire alignment of HKLR09 and TuenMun-Chek Lap Kok Link
(TMCLKL) during this quarterly period(Figure 1 of
Appendix J).
3.5.15Sighting
distribution of the present impact phase monitoring period (December 2015 to
February 2015) was compared to the one during the baseline monitoring period
(September to November 2011).In
the present quarter, dolphins have completely avoided the NEL region, which was
in stark contrast to their frequent occurrence around the BrothersIslands
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 eight quarters, which have
resulted in extremely low to zero dolphin encounter rate in this area.
3.5.16In
NWL survey area, dolphin occurrence was also drastically different between the
baseline and impact phase quarters.During the present impact monitoring period, much fewer dolphins
occurred in the middle portion of North Lantau region
than those during the baseline period, where dolphins supposedly moved between
their core areas around Lung Kwu Chau and the Brothers
Islands (Figure 1 of Appendix J).Moreover, more dolphins were sighted
near Sha Chau and Black Point during the baseline
period than those during the present impact monitoring period (Figure 1of Appendix
J).During the baseline period,
a number of dolphin groups were sighted to the west of Chek
Lap Kok airport (especially near the HKLR09
alignment) during the baseline period, while they have disappeared from this
area during the present impact phase period.
3.5.17Another comparison in dolphin distribution
was made between the three quarterly periods of winter months in 2012-13,
2013-14 and 2014-15 (Figure 2of Appendix
J).Among the three winter
periods, no dolphin sighting was made in NEL in 2014-15, while there were two
sightings made there in 2013-14, and eight sightings in 2012-13 (Figure 2of Appendix
J).This clearly indicated a
progressive decline in dolphin usage in NEL waters in the past few years.
3.5.18Moreover,
dolphins regularly occurred in the middle and western portions of North Lantau waters (especially between Black Point and Lung Kwu Chau, as well as around Sha
Chau) during the winter of 2012-13, but such usage has also progressively
diminished in 2013-14 and 2014-15 (Figure
2of
Appendix J).The temporal trend indicated that dolphin
usage in the overall North Lantau
region has greatly diminished during the winter months of the past few years.
Encounter Rate
3.5.19During 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 – November 2011) (See Table
3.5).
Table 3.4Dolphin
Encounter Rates (Sightings Per 100 km of Survey
Effort) During Reporting Period (Dec
2014 – Feb
2015)
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)
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
0.00
6.00 ± 5.05
0.00
22.19 ± 26.81
Northwest Lantau
2.91 ± 2.69
9.85 ± 5.85
11.27 ± 15.19
44.66 ± 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
3.5.20To 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 2.77 sightings and 9.62 dolphins per 100 km of
survey effort respectively, while the encounter rates of sightings (STG) and
dolphins (ANI) in NEL were both nil.
3.5.21In NEL, the average dolphin encounter rates (both STG and ANI) in
the present three-month impact monitoring period were zero, and such low
occurrence of dolphins in NEL have been consistently recorded in the past eight
quarters (Table 3.6). It is a serious concern that dolphin occurrence in NEL
in the eight quarters (0.0-1.0 for ER(STG) and 0.0-3.9 for ER(ANI)) have been
exceptionally low when compared to the baseline period (Table 3.6).Dolphins
have almost vacated from NEL waters since January 2014, with only one group of four dolphins sighted since then.
3.5.22Moreover, the average dolphin
encounter rates (STG and ANI) in NWL during the present impact phase monitoring
period were also much lower (reductions of 70.5% and 74.8% respectively) than
the ones recorded in the 3-month baseline period, indicating a dramatic decline
in dolphin usage of this survey area during the present impact phase period (Table 3.7).
Table 3.6Comparison of Average Dolphin Encounter Rates in Northeast Lantau
Survey Area from All Quarters of Impact Monitoring Period and Baseline
Monitoring Period (Sep – 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
± 5.05
22.19
± 26.81
December
2012-February
2013 (Impact)
3.14
± 3.21
6.33
± 8.64
March-May 2013 (Impact)
0.42
± 1.03
0.42
± 1.03
June-August 2013 (Impact)
0.88
± 1.36
3.91
± 8.36
September-November 2013 (Impact)
1.01
± 1.59
3.77
± 6.49
December
2013-February
2014 (Impact)
0.45
± 1.10
1.34
± 3.29
March-May 2014 (Impact)
0.00
0.00
June-August 2014 (Impact)
0.42
± 1.04
1.69
± 4.15
September-November 2014 (Impact)
0.00
0.00
December 2014-February 2015 (Impact)
0.00
0.00
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.
Table 3.7Comparison of Average
Dolphin Encounter Rates in Northwest Lantau Survey
Area from All Quarters of Impact Monitoring Period and Baseline Monitoring
Period (Sep – 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)
9.85 ± 5.85
44.66 ± 29.85
December
2012-February
2013 (Impact)
8.36 ± 5.03
35.90 ± 23.10
March-May 2013 (Impact)
7.75 ± 3.96
24.23 ± 18.05
June-August 2013 (Impact)
6.56 ± 3.68
27.00 ± 18.71
September-November 2013 (Impact)
8.04 ± 1.10
32.48 ± 26.51
December
2013-February
2014 (Impact)
8.21 ± 2.21
32.58 ± 11.21
March-May 2014 (Impact)
6.51 ± 3.34
19.14 ± 7.19
June-August 2014 (Impact)
4.74 ± 3.84
17.52 ± 15.12
September-November 2014 (Impact)
5.10 ± 4.40
20.52 ± 15.10
December
2014-February
2015 (Impact)
2.91 ± 2.69
11.27 ± 15.19
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.
3.5.23Notably, the last
eighth consecutive quarters have triggered the Action Levels under the Event
and Action Plan, while the current quarter has triggered the Limit Level.As discussed recently in Hung (2014),
the dramatic decline in dolphin usage of NEL waters in 2012 and 2013 (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 in 2012.It appeared that such noticeable decline
has already extended to NWL waters progressively in 2013 and 2014.
3.5.24A 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).
3.5.25For the comparison
between the baseline period and the present quarter (ninth quarter of the
impact phase being assessed), the p-value for the differences in average
dolphin encounter rates of STG and ANI were 0.0059 and 0.0330
respectively.If the alpha value is
set at 0.05, significant difference was detected between the baseline and
present quarters in both dolphin encounter rates of STG and ANI.
3.5.26For the comparison
between the baseline period and the cumulative quarters in impact phase (i.e.
first eight quarters of the impact phase being assessed), the p-value for the
differences in average dolphin encounter rates of STG and ANI were 0.0009 and
0.0003 respectively.Even if the
alpha value is set at 0.01, significant differences were detected in both the
average dolphin encounter rates of STG and ANI (i.e. between the two periods
and the locations).
3.5.27As indicated in both
dolphin distribution patterns and encounter rates, dolphin usage has been
significantly reduced in NEL and NWL waters 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 in North Lantau
waters could possibly link to the HZMB-related construction activities.
3.5.28To ensure the
continuous usage of North Lantau
waters by the dolphins, every possible measure should be implemented by the
contractors and relevant authorities to minimize all disturbances to the
dolphins.
Group Size
3.5.29Group size of
Chinese White Dolphins ranged from one to eight individuals per group in North Lantau
region during December 2014 to February 2015.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 3.8Comparison
of Average Dolphin Group Sizes between Reporting Period (December 2014 –
February 2015) and Baseline Monitoring Period (Sep– Nov 2011)
Average Dolphin Group
Size
Reporting Period
Baseline Monitoring
Period
Overall
3.47 ± 2.29 (n = 15)
3.72 ± 3.13 (n = 66)
Northeast Lantau
0.00
3.18 ± 2.16 (n = 17)
Northwest Lantau
3.47 ± 2.29 (n = 15)
3.92 ± 3.40 (n = 49)
3.5.30The average dolphin group sizes
in NWL waters during December 2014 to February 2015were slightly smaller than the ones recorded
during the three-month baseline period (Table
3.8).Ten of the 15 groups were
composed of 1-4 individuals only, while none of the dolphin group had more than
10 individuals.
3.5.31Distribution of dolphins with
larger group sizes (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 winter of 2014-15,
distribution of the few dolphin groups were concentrated near Lung Kwu Chau (Figure 3
of Appendix J). This distribution pattern was very different from the
baseline period, when the larger dolphin groups were distributed more evenly in
NWL waters with a few more sighted in NEL waters (Figure 3 of Appendix J).
3.5.32Notably, 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
3.5.33From December 2014 to February
2015, the most heavily utilized habitats by Chinese White Dolphins mainly
concentrated around Lung Kwu Chau and the northern
end of NWL survey area (Figures 4a and
4bof Appendix J).None of the grids in NEL recorded the presence
of dolphins in the present quarter.Moreover, all grids near HKLR03/HKBCF reclamation sites, HKLR09 or
TMCLKL alignment did not record any presence of dolphins during on-effort
search in the present quarterly period.
3.5.34However, 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.
3.5.35When compared with the habitat
use patterns during the baseline period, dolphin usage in NEL and NWL was
dramatically different from the present impact monitoring period (Figure 5of Appendix J).During the baseline
period, nine grids between Siu Mo To and Shum ShuiKok recorded moderately high
to high dolphin densities, which was in stark contrast to complete absence of
dolphins during the present impact phase period (Figure 5of Appendix J).
3.5.36The density patterns between the
baseline and impact phase monitoring periods were also very different in NWL,
with higher dolphin usage 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 (Figure
5of Appendix J).During the present impact phase period,
the dolphin usage was confined to the northwestern end of the survey area
around Lung Kwu Chau.
Mother-calf Pairs
3.5.37During the present quarterly
period, no young calves (i.e. unspotted calves or unspotted juveniles) for the first
time among the ten quarters of impact phase monitoring.This absence of young calves is also in
stark contrast to their regular occurrence during the baseline period.Their absences should be of a serious
concern, and the occurrence of calves should be closely monitored in the
upcoming quarters.
Activities and
Associations with Fishing Boats
3.5.38Only one dolphin sighting each
was associated with feeding and socializing activities respectively during the
three-month study period.The
percentage of sightings associated with feeding activities during the present
quarter (6.7%) was much lower than the one recorded during the baseline period
(11.6%).On the other hand, the
percentage of socializing activities during the present impact phase monitoring
period (6.6%) was slightly higher than the one recorded during the baseline
period (5.4%).None of the 15
dolphin groups were engaged in traveling or milling/resting behaviour.
3.5.39Distribution of dolphins engaged
in feeding and socializing activities during the present three-month period is
shown in Figure 6of Appendix J.The lone sightings
associated with feeding and socializing activities were located to the north of
the airport and near Lung Kwu Chau respectively (Figure 6of Appendix J).Distribution of dolphin
sightings associated with these activities during the impact phase was very
different from the distribution pattern of these activities during the baseline
period (Figure 6of Appendix J).
3.5.40As in the past monitoring
quarters, none of the 15 dolphin groups was found to be associated with an
operating fishing vessel in North Lantau
waters during the present impact phase period.The extremely rare events of fishing
boat association in the present and previous quarters were consistently found,
and were likely related to the recent trawl ban being implemented in December
2012 in Hong Kong waters.
Photo-identification
and Individual Range Use
3.5.41From December 2014 to February
2015, over 1,500 digital photographs of Chinese White Dolphins were taken
during the impact phase monitoring surveys for the photo-identification work.
3.5.42In total, 24 individuals sighted
32 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 32
re-sightings were made in NWL.
3.5.43The majority of identified
individuals were sighted only once or twice during the three-month period, with
the exception of one individual (CH34) being sighted thrice.
3.5.44Two of these 24 individuals
(NL259 and NL285) were also sighted in West Lantau
waters during the HKLR09 monitoring surveys for the same three-month period,
showing their extensive movement between North and West Lantau
regions.
Five recognized females (NL98, NL104, NL123, NL202 and WL17) were accompanied
with calves during their re-sightings. Some of these mothers were frequently
sighted with their calves throughout the HKLR03 impact phase monitoring period
since October 2012. Individual range use
3.5.45Ranging patterns of the 24
individuals identified during the three-month study period were determined by
fixed kernel method, and are shown in Annex Vof Appendix J.
3.5.46All identified dolphins sighted
in this quarter were utilizing their range use in NWL, but have avoided the NEL
waters where many of them have utilized as their core areas in the past (Annex Vof 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 during the baseline period.
3.5.47Notably, two individuals (NL259
and NL285) sighted in NWL and NEL waters consistently in the past have extended
their range use to WL waters in the present quarter.It should be further monitored to
examine whether there has been any consistent shifts of home ranges of individuals
from North Lantau to
West Lantau, which
could also possibly be related to the HZMB-related construction works.
Action Level / Limit
Level Exceedance
3.5.48There was one Limit Levelexceedance of dolphin monitoring for the quarterly
monitoring data (December 2014 – February 2015). According
to the contractor’s information, the marine activities undertaken for HKLR03
during the quarter of December 2014 to February 2015 included reclamation,
excavation of stone platform, surcharge activities, construction of seawall,
temporary drainage diversion and ground investigation. There is no evidence
showing the current Limit Level 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 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.In addition, the contractor
will implement proactive mitigation measures such as avoiding anchoring at
Marine Department’s designated anchorage site – Sham ShuiKok Anchorage (near Brothers Island) as far as
practicable.
3.5.49A 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).
3.5.50For the comparison between the
baseline period and the present quarter (ninth quarter of the impact phase),
the p-value for the differences in average dolphin encounter rates of STG and
ANI were 0.0059 and 0.0330 respectively.If the alpha value is set at 0.05, significant difference was detected
between the baseline and present quarters in both encounter rates of STG and
ANI.
3.5.51For the comparison between the
baseline period and the cumulative quarters in impact phase (i.e. first nine
quarters of the impact phase), the p-value for the differences in average
dolphin encounter rates of STG and ANI were 0.0009 and 0.0003
respectively.Even if the alpha
value is set at 0.01, significant difference was detected in both the average dolphin
encounter rates of STG and ANI (i.e. between the two periods and the
locations).
3.5.52The AFCD monitoring data during
December 2014 to February 2015 has been reviewed by the dolphin specialist, and
no dolphin was sighted from 103.64 km of survey effort on primary lines in NEL
during the same quarter.This
review has confirmed that the extremely low occurrence of dolphins reported by
the HKLR03 monitoring survey in winter 2014-15 in NEL is accurate.
3.5.53There 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.
3.5.54All dolphin protective measures
are fully and properly implemented in accordance with the EM&A Manual.
According to the Marine Travel Route Plan, if vessels are crossing along edge of
the proposed marine park, the travelling speed will keep not exceeding 5 knots
when crossing the edge of the proposed marine park. The Contractor will
continue to provide training for skippers to ensure that their working vessels
travel from source to destination to minimize impacts on Chinese White Dolphin
and avoid anchoring at Marine Department’s designated anchorage site - Sham ShuiKok 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.
3.5.55A
meeting was held on 27 April 2015 with attendance of ENPO, Resident Site Staff
(RSS), Environmental Team (ET) and dolphin specialist for Contract No. HY/2010/02, RSS, ET, dolphin specialist and main Contractor for
Contract No.HY/2011/03. The
discussion/recommendation as recorded in the minutes of the meeting, which
might be relevant to HKLR03 Contract are summarized below.
3.5.56It
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.
3.5.57It
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.
3.5.58It
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.
3.5.59It
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.
3.5.60It
was suggested that the protection measures (e.g., speed limit control) for the
proposed Brothers Island Marine Park (BMP) shall be brought forward as soon as
possible before its establishment so as to provide a better habitat for dolphin
recovery. It was noted that under the Regular Marine Travel Route Plan, the
contractors have committed to reduce the vessel speed in BMP.
3.5.61There
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.
3.6Mudflat
Monitoring Results
Sedimentation Rate
Monitoring
3.6.1The baseline sedimentation rate monitoring was in
September 2012 and impact sedimentation rate monitoring was undertaken on 13
December 2014.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 3.8Measured
Mudflat Surface Level Results
Baseline Monitoring
(September 2012)
Impact Monitoring
(December 2014)
Monitoring Station
Easting (m)
Northing (m)
Surface Level
Easting (m)
Northing (m)
Surface Level
(mPD)
(mPD)
S1
810291.160
816678.727
0.950
810291.034
816678.685
1.050
S2
810958.272
815831.531
0.864
810958.223
815831.493
0.915
S3
810716.585
815953.308
1.341
810716.537
815953.273
1.469
S4
811221.433
816151.381
0.931
811221.458
816151.337
1.055
Table 3.9Comparison
of measurement
Comparison of measurement
Remarks and
Recommendation
Monitoring Station
Easting (m)
Northing (m)
Surface Level
(mPD)
S1
-0.126
-0.042
0.100
Level
continuously increased
S2
-0.049
-0.038
0.051
Level
continuously increased
S3
-0.048
-0.032
0.128
Level
continuously increased
S4
0.025
-0.044
0.124
Level
continuously increased
3.6.2This 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
3.6.3The 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.
3.6.4Impact water quality
monitoring in San Tau (monitoring station SR3) was conducted in December 2014.The monitoring parameters included
dissolved oxygen (DO), turbidity and suspended solids (SS).
3.6.5The
Impact monitoring result for SR3 were extracted and summarised below:
Table 3.10Impact
Water Quality Monitoring Results (Depth Average)
Date
Mid Ebb Tide
Mid Flood Tide
DO (mg/L)
Turbidity (NTU)
SS (mg/L)
DO (mg/L)
Turbidity (NTU)
SS (mg/L)
01-Dec-14
6.49
3.00
5.95
6.93
8.70
10.80
03-Dec-14
6.67
4.85
6.80
6.80
9.70
11.25
05-Dec-14
6.70
5.80
11.15
7.08
6.10
11.40
08-Dec-14
7.25
4.65
5.20
7.16
4.40
5.40
10-Dec-14
7.43
3.80
4.60
7.40
2.75
3.30
12-Dec-14
7.93
2.05
4.75
7.67
3.10
5.20
15-Dec-14
8.65
1.55
1.60
8.45
3.05
3.90
17-Dec-14
8.46
2.60
2.35
9.29
2.75
3.20
19-Dec-14
8.76
0.70
2.55
8.88
0.50
2.30
22-Dec-14
8.93
1.80
2.10
8.82
1.35
3.75
24-Dec-14
8.63
2.50
2.40
8.60
1.45
2.50
26-Dec-14
8.49
1.25
2.85
8.65
1.60
3.65
29-Dec-14
7.77
1.70
3.75
8.01
1.55
7.70
31-Dec-14
8.18
1.35
2.30
8.44
0.95
3.35
Average
7.88
2.69
4.17
8.01
3.43
5.55
Mudflat Ecology Monitoring
Sampling Zone
3.6.6There 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 present survey was conducted in December 2014 (totally 6 sampling days between 6thand 23rd December 2014).The
locations of sampling zones are shown in Annex
I of Appendix O.
Horseshoe Crabs
3.6.7Active search method wasconducted for
horseshoe crab monitoringby 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 in low tide period (tidal level
below 1.2 m above Chart Datum (C.D.)). Once a horseshoe crab individualwas found, the
species was identified referencing to Li (2008). The prosomal width, inhabiting substratumand 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 10th (for TC1
and TC2) and 23rd (for TC3 and ST) December 2014. The weather was
cloudy on both survey days.
Seagrass Beds
3.6.8Active 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 in low tide period. Once seagrass bed was
found, the species, estimated area, estimated coverage percentage and respective GPS coordinate were
recorded. A photographic record was taken for future investigation. The seagrass beds surveys were conducted on
10th (for TC1 and TC2) and 23rd (for TC3 and ST) December
2014.
Intertidal Soft Shore Communities
3.6.9The intertidal soft shore
community surveys were conducted in low tide period on 6th (for
TC1), 7th (for TC2), 21st (for TC3) and 22nd
December 2014 (for ST). At each sampling zone, three 100m horizontal transects were laid at high
tidal level (H: 2.0m above C.D.), mid tidal level (M: 1.5m above C.D.) and low
tidal level (L: 1.0m above C.D.). Along everyhorizontal transect, ten random quadrats (0.5 m x 0.5m) were placed.
3.6.10Inside aquadrat, 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 mmin-situ. Any
visible infauna were collected and identified.
Finally the top 5 cm surface sediments was dug for
visible infauna in the quadrat
regardless of hand core sample was taken.
3.6.11All collected fauna were released after recording except some tiny
individuals that are too small to be identified on
site. These tiny individuals were takento
laboratory for identification under dissecting microscope.
3.6.12The 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
3.6.13Data 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’= -Σ ( 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
3.6.14Table 3.1 and Figure 3.1 of Appendix Oshows the records of horseshoe crab survey at
every sampling zone. Two individuals ofCarcinoscorpiusrotundicauda was found in TC1 only.Few individuals of Tachypleustridentatus were foundin sampling zones TC3 (3 ind.) andST (5 ind.). All individuals
were found on fine sand or soft mud substrata. Every sight record consisted of single individual that no groupingbehaviour was observed.
3.6.15Table 3.2 of Appendix O summarizes the survey results
of horseshoe crab at every sampling zone.For Carcinoscorpiusrotundicauda, the search records were0.5ind. hr-1 person-1 (mean prosomal width:41.53 mm), in TC1. According to Li (2008), the prosomal width of recorded
individuals ranged32.13-50.92 mmthat
was
about 5.3-8.2 years old. For Tachypleustridentatus,the search
record was0.8ind. hr-1 person-1 (46.86 mm) and 1.3 ind. hr-1 person-1 (64.03 mm) in TC3 and ST respectively.The
prosomal width of recorded individuals ranged37.27-72.40 mmthat
was
about4.6–8.5 years old.
3.6.16No marked individual of horseshoe crab was
recorded in present survey. Some marked individuals were found in previous
surveys conducted in Sep. 2013, Mar. 2014 and Sep. 2014. All of them were released
through a conservation programme conducted by Prof.
Paul Shin (Department of Biology and Chemistry, The City University of Hong
Kong (CityU)). It was a re-introduction trial of
artificial bred horseshoe crab juvenile at selected sites. So that the
horseshoe crabs population might be restored in the natural habitat. Through a
personal conversation with Prof. Shin, about 100 individuals were released in
the sampling zone ST on 20 June 2013. All of them were marked with color tape
and internal chip detected by specific chip sensor. There should be second
round of release between June and September 2014 since new marked individuals
were found in the survey of September 2014.
3.6.17The 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
3.6.18Figure 3.2 and 3.3 of Appendix O show the changes of number of individuals, mean prosomal width
and search record of horseshoe crabs Carcinoscorpiusrotundicaudaand Tachypleustridentatus respectively in every sampling zone along the sampling months. In
general, higher search
records (i.e. number of individuals) of both species were always found in ST
followed by TC3. In contrast, much lower search record was found in
other sampling zones especially TC2 (2 ind. in Sep.
2013, 1 ind. in Mar., Jun. and Sep. 2014). There was
no spatial difference of horseshoe crab size (prosomal
width) among the sampling zones.
3.6.19It was obvious 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). Relatively, TC3
might be functioning as less important nursery ground adjacent to ST due to
moderate but fluctuate number of horseshoe crab found. 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 found in TC1, TC2
and TC3 were believed foraging from the ST during high tide while it might
return to ST over a certain period of time. It accounted for the variable
search records in the sampling zones along the sampling months. For example,
few individuals of Tachypleustridentatus were found in TC1 only between Sep. 2012 and Sep. 2013. However it no
longer appeared while few individuals of Carcinoscorpiusrotundicauda were found after Mar. 2014.
Seasonal variation of horseshoe crab population
3.6.20Throughout the monitoring period conducted, the search record of
horseshoe crab declined obviously during dry season especially December (Figures 3.2 and 3.3 of Appendix O). In present survey (Dec. 2014), 2 individuals of Carcinoscorpiusrotundicauda and 8 individuals of Tachypleustridentatus were found only. Furthermore no individual of either two species was found in the previous survey of Dec.
2013. 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 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-1and 0 ind. hr-1
person-1in wet season and dry
season respectively (details see Li, 2008). After the dry season, the search
record increased with the warmer climate.
3.6.21Between the sampling months Sep.
2012 and Dec. 2013, Carcinoscorpiusrotundicauda
was a less common species relative to Tachypleustridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This species
had been believed of very low density in ST hence the encounter rate was very
low. Until Mar. 2014, it was found in all sampling zones with higher abundance
in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and
spawning of this species had occurred 3-4 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 Mar. to Sep. 2014, more individuals were recorded due to
larger size and higher activity.
3.6.22For Tachypleustridentatus, sharp increase of
number of individuals was recorded in ST with wet season (from Mar. to Sep.
2013). 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 during the period of this year. The
number of individuals increased in Mar. and Jun. 2014 followed by a rapid
decline in Sep. 2014. Apart from natural mortality, migration from
nursery soft shore to subtidal habitat was another
possible cause. Since the mean prosomal width of Tachypleustridentatus continued to grow and reached about 50 mm in this year. Most of the
individuals might have reached a suitable size strong enough to forage in subtidal habitat.
3.6.23Figure 3.4
of Appendix O shows the changes of prosomal width of
horseshoe crab Carcinoscorpiusrotundicauda and Tachypleustridentatus in ST where was
regarded as an important nursery ground. As mentioned above, Carcinoscorpiusrotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the data were
limiting. From Mar. to Sep. 2014, the size of major population (50% records between upper and
lower quartile) fluctuated between 30-40 mm and 45-60 mm. Such fluctuation should be due to
variable encounter rate influenced by weather. For Tachypleustridentatus, 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.
Impact of the HKLR project
3.6.24The present survey was the eighth
time 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 considering the
factor of natural, seasonal variation. In case, abnormal phenomenon (e.g. very few numbers of horseshoe crab individuals in warm weather, large number of dead individuals on the shore)
is observed, it would be reported as soon as possible.
Seagrass Beds
3.6.25Table 3.3of Appendix O show the records of seagrass beds survey at
every sampling zone. Three small patches of Zostera japonicawere found on sandy substratum nearby the seaward side of mangrove area at tidal
level 2.0 m above C.D.(Figure 3.5 of Appendix
O). The estimated area ranged0.3-4.2 m2 while
the estimated vegetation coverage was 20-40%. The total area and average area of seagrass
beds were 4.7 m2 and 1.6 m2 respectively (Table 3.4 of Appendix
O). Another seagrass species Halophilaovalis(Figure 3.5 of Appendix
O).was no longer found in present survey but it used to be abundant and
extensive in previous surveys.
Temporal variation of seagrass beds
3.6.26Figure 3.6 of Appendix Oshows 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 seagrassHalophilaovalis. Then the patch Jun.
2014, the patch size increased obviously again (41 m2) with warmer
climate. Similar to size increased and merged gradually with the warmer climate
from Mar. to Jun. 2013 (15 m2). However the patch size decreased
sharply and remained similar from Sep. 2013 (4 m2) to Mar. 2014 (3 m2).
In previous year, the patch size decreased again and remained similar Sep. 2014
(2 m2) to Dec. 2014 (5 m2, present survey).
3.6.27For Halophilaovalis, 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 the Dec. 2013 (first survey). The total seagrass bed area grew steadily
from 332.3 m2 in Sep. 2012 to 727.4 m2 in Dec. 2013.
Flowers could be observed in the largest patch during its flowering
period in Dec. 2013. 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 others. These patches were no longer
distinguishable and were covering a significant mudflat area of ST. It was
generally grouped into 4 large areas (1116 – 2443 m2) of seagrass beds characterized of patchy distribution,
variable vegetable coverage (40-80%) and smaller leaves. The total seagrass bed area increased sharply to 7629 m2.
In Sep. 2014, the total seagrass area declined
sharply to 1111 m2. There were only 3-4 small to large patches
(6-253 m2) at high tidal level and 1 patch at low tidal level (786 m2). Typhoon or strong water current was a possible cause (Fong, 1998). In Sep. 2014,
there were two tropical cyclone records in Hong Kong (7th-8th
Sep.: no cyclone name, maximum signal number 1; 14th-17th
Sep.: Kalmaegi maximum signal number 8SE) before the seagrass survey dated 21st Sep. 2014. The strong
water current caused by the cyclone, Kalmaegi
especially, might have given damage to the seagrass
beds. In addition, natural heat stress and grazing force were other possible
causes reducing seagrass beds area. Besides, Halophilaovalis could be found in other
mud flat area surrounding the single patch. But it was hardly distinguished
into patches due to very low coverage (10-20%) and small leaves.
3.6.28In Dec. 2014 (present survey), all the seagrass
patches of Halophilaovalis disappeared in ST.The seagrass bed of Halophilaovalisrecorded in December
survey was significantly differentfrom the baseline
condition.Figure 3.7 of Appendix
O
shows the difference of the original seagrass beds
area nearby the mangrove vegetation at high tidal level between Jun. 2014 and
Dec. 2014. Such rapid loss would not be seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m above C.D.) were
present and normal in December 2012 and 2013. According to Fong (1998), similar
incident had occurred in ST in the past. The original seagrass
area had declined significantly during the commencement of the construction and
reclamation works for the international airport at Chek
Lap Kok in 1992. The seagrass
almost disappeared in 1995 and recovered gradually after the completion of
reclamation works. Moreover, incident of rapid loss of seagrass
area was also recorded in another intertidal mudflat in Lai Chi Wo in 1998 with unknown reason. Hence Halophilaovalis 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 seagrassHalophilaovalis
3.6.29Typhoon or strong water current was suggested as one unfavourable
condition to Halophilaovalis (Fong, 1998). As
mentioned above, there were two tropical cyclone records in Hong Kong in Sep.
2014. The strong water current caused by the cyclones might have given damage
to the seagrass beds.
3.6.30Prolonged light deprivation due to turbid water would be another unfavouable condition. Previous studies reported that Halophilaovalis 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 Longstaffet 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).
3.6.31In order to investigate any
deterioration of water quality (e.g. more turbid) in ST, the water quality
measurement results at two closest monitoring stations SR3 and IS5 of the
EM&A programme were obtained from the water
quality monitoring team. Based on the results from June to December 2014, the
overall water quality was in normal fluctuation except there was one exceedance of suspended solids (SS) at both stations in
September. On 10th Sep., 2014, the SS concentrations measured 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 Sep. 2014 (daily total rainfall at the Hong
Kong International Airport: 0-2.1 mm; extracted from the climatological
data of Hong Kong Observatory). The effect of upstream runoff on water quality
should be neglectable in that period. Moreover the exceedance of water quality was considered unlikely to be
related to the contract works of HKLR according to the ‘Notifications of
Environmental Quality Limits Exceedances’ provided by
the respective environmental team. The respective construction of seawall and
stone column works, which possibly caused turbid water, were
carried out within silt curtain as recommended in the EIA report. Moreover
there was no leakage of turbid water, abnormity or malpractice recorded during
water sampling. In general, the exceedance of
suspended solids concentration was considered to be attributed to other
external factors, rather than the contract works.
3.6.32Based on the weather condition and water quality results in ST, the
co-occurrence of cyclone hit and turbid waters in Sep. 2014 might have combined
the adverse effects on Halophilaovalisthat leaded to disappearance of this short-lived and r-strategy seagrass
species. Fortunately Halophilaovalis was a fast-growing
species (Vermaatet 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 Halophilaovalis might recolonize the mudflat of ST through seed reproduction as
long as there was no unfavourable condition in the
coming months.
Impact of the HKLR
project
3.6.33The present survey was the ninth survey of the EM&A programme during the construction period. Based on the results, there was a complete
disappearance of seagrassHalophilaovalis in the sampling zone
ST. The combined effects of cyclone hits and turbid water incidence in Sep.
2014 were believed the cause. For the turbid water incidence (i.e. exceedance of SS concentration), there was no evidence
indicating correlation between the turbid water and the contract works of HKLR
(e.g. construction of seawall, stone column works)
as mentioned above. Hence
the negative impact of HKLR project on the seagrass
was not significant.
3.6.34As long as there is no unfavourable
condition to Halophilaovalis, it is believed that
the seagrass beds would recover gradually in ST in
the coming months. Because it is ar-strategy seagrass species that can colonize
areas in short period (Fong, 1998).
3.6.35Recently no follow-up action is suggested. In case the disappearance of seagrass beds Halophilaovalis persists until June 2015, some follow-up actions should be taken. For
examples, more water quality parameters relevant to the seagrass
toxicity (e.g. herbicides and heavy metals) should be included in the water
quality monitoring programme. It is to investigate
any seagrass toxicity present in the water that is
omitted in the original EM&A programme. Moreover,
seagrass transplantation may be adopted to fasten the
recovery of seagrass beds.
Intertidal Soft
Shore Communities
3.6.36Table 3.5 and Figure 3.8 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 categorizing the
substratum types (Gravels & Boulders / Sands /
Soft mud) of the ten random quadrats along the horizontal transect. The distribution of substratum types
varied among tidal levels and sampling zones:
·In TC1, the distribution of substratum varied
among three tidal levels. At high tidal level, there was higher percentage of
‘Gravels and Boulders’ (50%) followed by ‘Sands’ (30%) and ‘Soft mud’ (20%). At
mid tidal level, ‘Gravels and Boulders’ (90%) was the main substratum. At low
tidal level, there was higher percentage of ‘Sands’ (50%) followed by ‘Gravels
and Boulders’ (30%)’and ‘Soft mud’ (20%).
·In
TC2, high percentage of ‘Sands’ (70%) were recorded at all tidal levels. ‘Gravels and Boulders’
(20-30%) was the second abundant at high and mid tidal levels while ‘Soft mud’
(20%) was the second abundant at low tidal level.
·In TC3, the distribution of substratum varied
among three tidal levels. High percentages of ‘Sands’ (70%)
was recorded at high tidal level followed by ‘Soft mud’ (30%). In
contrast, high percentages of ‘Soft mud’ (70%) was recorded at mid tidal level
followed by ‘Sands’ (30%). ‘Gravels and Boulders’ was the major substratum type
(70%) at low tidal level.
·In ST, ‘Gravels and Boulders’ (100%) was the
major substratum at high and mid tidal levels. ‘Soft mud’ (50%) and ‘Sands’
(40%) were mainly recorded at low tidal level.
3.6.37There 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.
3.6.38Table 3.6of Appendix Olists the total abundance, density and number of taxon
of every phylum in the present
survey. A total of 10051 individuals
were recorded. Mollusca was significantly the most
abundant phylum (total individuals 9813, density 327 ind.
m-2, relative abundance 97.6%). The second abundant phylum was Arthropoda (105 ind., 4 ind. m-2,
1.0%). The third abundant phylumwasAnnelida (80 ind., 3 ind. m-2,
0.8%).Relatively other phyla were very low in
abundances (density £1 ind. m-2, relative abundance £0.3%). Moreover, the most diverse phylum wasMollusca (37taxa) followed by Arthropoda (11taxa) and Annelida (10 taxa). There was one taxon
recorded only in other phyla. The complete list of collected specimens is shown in Annex III of Appendix O.
3.6.39Table 3.7of Appendix Oshows the number of
individual, relative abundance and density of each phylum in every sampling
zone. The total abundance (1528-4072 ind.) varied largely among the four sampling zones although
the phyla distributionswere
similar. In general, Molluscawas the
most dominant phylum (no. of individuals: 1455-3999ind.; relative abundance 95.2-98.2%; density 194-533 ind. m-2). Other phyla were significantly lower in number of individuals.Arthropoda (12-38ind.;10.5-2.5%; 2-5 ind. m-2) and Annelida (12-32 ind.;
0.5-1.5%; 2-4 ind. m-2) were the second or third abundant
phyla. In ST, Cnidaria
(sea anemone) was the forth abundant phylum (12 ind.;0.6%; 2 ind. m-2).Relatively, other phyla were low in abundance among the four sampling zones (< 0.5%).
Dominant
species in every sampling zone
3.6.40Table 3.8of Appendix Olists the abundant
species (relative abundance >10%) in every sampling zone. In TC1, gastropod Batillariamultiformis was the most abundant (203ind. m-2, relative abundance 73%)at high tidal level (major substrata: ‘Gravels
and Boulders’ and ‘Sands’). At mid and low tidal levels (major substrata: ‘Gravels and Boulders’
and ‘Sands’), rock
oyster Saccostreacucullata
(151-176ind. m-2,
39-53%, attached on boulders) and gastropod Monodontalabio (40-76ind. m-2,
12-19%) were the first and second abundant taxa. Moreover gastropod Batillariamultiformis was the third abundant (72ind. m-2, 18%)at mid tidal levels.
3.6.41At TC2, gastropodsCerithideadjadjariensis(68ind. m-2, 36%), Cerithideacingulata (26ind. m-2,
14%) and rock oyster Saccostreacucullata (43ind. m-2, 26%)were common taxa at low-moderate densities (major substratum: ‘Sands’). At mid and low tidal levels (major substrata: ‘Sands’), rock oyster Saccostreacucullata (84-136ind. m-2, 51-52%) was the most abundant followed by gastropod Batillariazonalis(32-39ind. m-2,
12-24%) at low-moderate densities. Moreover,
gastropod Cerithideadjadjariensis(27ind. m-2,
10%)was another
common taxon at low-moderate density at mid tidal levels.
3.6.42At TC3,
gastropodBatillariamultiformis(549ind. m-2, 66%) was
high in density at high tidal level followed by gastropodCerithideadjadjariensis (180ind. m-2, 22%) at
moderate density (major substratum: ‘Sands’). At mid tidal level (major
substratum: ‘Soft mud’), gastropodCerithideadjadjariensis (176ind. m-2,
54%) was the most abundant at moderate density
followed by gastropod Cerithideacingulata(69ind. m-2,
21%). At low tidal level
(major substratum: ‘Gravels and Boulders’), rock oyster Saccostreacucullata (208ind. m-2, 44%) was the most abundant at moderate density
followed by gastropods Monodontalabio(126ind. m-2,
27%) and Batillariamultiformis(49ind. m-2, 10%) at
much lower densities.
3.6.43At ST,
gastropod Batillariamultiformis wasmost
abundant (106ind. m-2, 35%) at
moderate density at high tidal level (major substratum: ‘Gravels and Boulders’)
followed by much less abundant gastropod Monodontalabio(68 ind. m-2, 23%) and
rock oyster Saccostreacucullata(59 ind. m-2, 20%). At
mid tidal level (major substratum: ‘Gravels and Boulders’), rock oyster Saccostreacucullata(145 ind. m-2, 37%) was
the most abundant at moderate density. Other less abundant taxa
were gastropods Lunellacoronata(66ind. m-2, 17%),Monodontalabio(64 ind. m-2, 16%) and Batillariamultiformis (38ind. m-2, 10%) at low densities. At low tidal level (major
substrata: ‘Sands’ and ‘Soft mud’), rock oyster Saccostreacucullata (26ind. m-2, 31%),
gastropods Batillariazonalis(20ind. m-2,
24%) and Lunellacoronata(9ind. m-2, 11%) were abundant taxa
at low densities relative to that at high and mid tidal levels.
3.6.44There was no consistentzonation pattern of species distribution observed across all sampling zones and tidal levels. The
species distribution should be
affected by the type
of substratum primarily. In general, gastropods Batillariamultiformis (total number of individuals: 2683 ind., relative abundance 26.7%) and Cerithideadjadjariensis (1274 ind., 12.7%)
were the most commonly occurring species on sandy and soft mud substrata. Rock oyster Saccostreacucullata(2646 ind., 26.3%) and gastropod Monodontalabio
(1041 ind., 10.4%) were commonly occurring species inhabiting
gravel and boulders substratum.
Biodiversity
and abundance of soft shore communities
3.6.45Table 3.9of Appendix O shows the mean
values of number of species, density, biodiversity
index H’and species
evennessJof soft shore communities at every tidal level and in every sampling zone. Among the sampling zones, there was no clear difference in the mean number
of species (5-14 spp. 0.25 m-2). But the mean densities of TC3
(328-828 ind. m-2) were highest followed
by TC1 (280-390 ind. m-2) and ST (84-396 ind. m-2). TC2 was relatively lowest at mean
densities (164-261 ind. m-2). The mean H’ (1.57) and J (0.75) in
ST were relatively higher than that in TC1, TC2 and TC3 (H’: 1.15-1.33; J:
0.60-0.69).
3.6.46Across the tidal levels, there
was no consistent difference of the mean number of species, H’ and J in all sampling zones. The mean densities were similar among the
three tidal levels in TC1 (280-390 ind. m-2)
and TC2 (164-261 ind. m-2). In TC3, the
mean density at high tidal level (828 ind.
m-2) was much higher than mid and low tidal levels (328-472 ind. m-2). In ST, the mean densities at high and
mid tidal levels (300-396 ind. m-2) were
much higher than low tidal level (84 ind.
m-2).
3.6.47Figures 3.9 to 3.12 of Appendix Oshow the temporal changes of mean number
of species, mean density,
H’ andJat every tidal level
and in every sampling
zone along the sampling months. No consistent
temporal change of any biological parameters was observed. All the parameters
were under slight and natural fluctuation with the seasonal variation. Focused
on present survey (Dec. 2014), declines of mean density was observed in TC1,
TC2 and ST. It was believed the cause of higher mortality during cold, dry
season.
Impact of
the HKLR project
3.6.48The present survey was the ninth 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. large
reduction of fauna densities and species
number) is
observed, it would be reported as soon as possible.
3.7.1The 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.
3.7.2The summary of waste flow table is detailed in Appendix K.
3.7.3The 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 Practise on
the Packaging, Labelling and Storage of Chemical Wastes.
3.8Environmental
Licenses and Permits
3.8.1The valid environmental licenses and permits during
the reporting period are summarized in Appendix
L.
4.1.1The 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
4.1.2No
Action and Limit Level exceedances of 1-hour TSP and
no Limit Level exceedance of 24-hour TSP were
recorded at AMS5 and AMS6 during the reporting period.
4.1.3An
Action Level exceedance of 24-hour TSP at AMS5 was
recorded on 21 January 2015. An Action Level exceedances of 24-hour TSP at AMS6 was recorded on 16 December 2014 and 21 January 2015 respectively.
Noise
4.1.4There were no Action and Limit Level exceedances
for noise during daytime on normal weekdays of the reporting period.
Water Quality
4.1.5During the reporting period, five Action Level exceedances
and two
Limit Level exceedancesfor suspended solid level were recorded. No
exceedances
of Action and Limit
Level for
dissolved oxygen level and turbidity
were recorded. There were no specific
activities recorded during the monitoring period that would cause any
significant impacts on monitoring results and no leakage of turbid water or any
abnormity or malpractice was observed during the sampling exercise.Therefore, all exceedances
were considered as non-contract related. The detailed numbers of exceedances
recorded during the reporting period at each impact
station are summarised in Table 4.1.
Dolphin
4.1.6There
was one Limit Levelexceedance of
dolphin monitoring for the quarterly monitoring data (December 2014 – February 2015). According
to the contractor’s information, the marine activities undertaken for HKLR03
during the quarter of December 2014 to February 2015 included reclamation,
excavation of stone platform, surcharge activities, construction of seawall,
temporary drainage diversion and ground investigation.
4.1.7There 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 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.In addition, the contractor will
implement proactive mitigation measures such as avoiding anchoring at Marine
Department’s designated anchorage site – Sham ShuiKok Anchorage (near Brothers Island) as far as
practicable.
4.1.8All dolphin protective measures are fully and properly implemented in
accordance with the EM&A Manual. According to the Marine Travel Route Plan,
if vessels are crossing along edge of the proposed marine park, the travelling
speed will keep not exceeding 5 knots when crossing the edge of the proposed
marine park. The Contractor will continue to provide training for skippers to
ensure that their working vessels travel from source to destination to minimize
impacts on Chinese White Dolphin and avoid anchoring at Marine Department’s
designated anchorage site - Sham ShuiKok 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.
Table 4.1Summary
of Water Quality Exceedances
Station
Exceedance Level
DO (S&M)
DO (Bottom)
Turbidity
SS
Total Number of Exceedances
Ebb
Flood
Ebb
Flood
Ebb
Flood
Ebb
Flood
Ebb
Flood
IS5
Action Level
--
--
--
--
--
--
26 Jan 2015
--
1
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS(Mf)6
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS7
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS8
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS(Mf)9
Action Level
--
--
--
--
--
--
--
12 Jan 2015
0
1
Limit Level
--
--
--
--
--
--
5 Dec 2014
--
1
0
IS10
Action Level
--
--
--
--
--
--
--
21 Jan 2015
0
1
Limit Level
--
--
--
--
--
--
--
--
0
0
SR3
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR4
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR5
Action Level
--
--
--
--
--
--
--
21 Jan 2015
23 Jan 2015
0
2
Limit Level
--
--
--
--
--
--
--
--
0
0
SR10A
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
23 Jan 2015
0
0
SR10B
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
Total
Action
0
0
0
0
0
0
1
4
5**
Limit
0
0
0
0
0
0
1
1
2**
Notes:
S: Surface;
M: Mid-depth;
**The total exceedances.
4.2Summary of
Environmental Complaint, Notification of Summons and Successful Prosecution
4.2.1There were two environmental
complaints received during the reporting period. The summary of environmental complaints
is presented inTable 4.2.
The details of cumulative statistics of Environmental Complaints are provided
in Appendix N.
Table 4.2A Summary of Environmental Complaints for the Reporting
Period
Environmental
Complaint No.
Date of Complaint
Received
Description of
Environmental Complaints
COM-2014-063
3 December 2014
Noise
COM-2014-065
24 December 2014
Water Quality
4.2.2No notification of summons and prosecution was received during the
reporting period.
4.2.3Statistics on notifications of summons and successful prosecutions are
summarized in Appendix M.
5.1.1According to the environmental
site inspections undertaken during the reporting period, the following recommendations
were provided:
§The Contractor was reminded to remove the rubbish from the shore of S16, S7, S11, S15, S22, S25, N1 and N20.
§The Contractor was reminded to
provide a drip tray for the chemical containers on vessel Sing Kee, N1 and N4.
§The Contractor was reminded to
spray water on the stockpile of fill material at N13.
§The Contractor was reminded to
remove the stagnant water from the drip tray at N4.
§The Contractor was reminded to
clean up the oil stains on the unpaved road at N13.
§TheContractor was reminded to remove the rubbish in the U channel and
divert the wastewater to a treatment facility for treatment at N13.
§The Contractor was reminded to provide a drip tray for the oil drums at S11 and S25.
§The Contractor was reminded to
provide sorting for the waste generated from the Contact and disposed of them
regularly.
§The Contractor was reminded to
clean up the stagnant water at N1, N20, S11, S19, WA4 and WA6.
§The Contractor was reminded to
replace the broken rubbish bin at N13.
§The Contractor was reminded to
clean up the oil stains inside the sheet pile at S11.
§The Contractor was reminded to spray water during the percussive
activity at S15.
§The Contractor was reminded to
clean up the slurry which observed on barge edge of vessel Shun Tat 82.
§The Contractor was reminded to
remove the excess fill material on barge edge of vessel KiuTak.
§The Contractor was reminded to
clean up the muddy water at S7 and S8.
§The Contractor was reminded to clean up the oil stains and provide a
drip tray for the air compressor at N4.
§The Contractor was reminded to
replace the broken sand bags along the barge edge.
§The Contractor was asked to stop
discharging the untreated wastewater into the sea at S11 and treat
the wastewater prior to discharge.
§The Contractor was reminded to clean up the sundries at S15.
§The Contractor was reminded to
spray water for the stockpiles of fill material at S22 a d N13.
§The Contractor was reminded to
remove the crushed stones and keep functional of the wheel washing bay at N20.
§The Contractor was reminded to
provide bunds/sand bags along gullies at N20 to prevent washing away of sand
into the gullies.
§The Contractor was reminded to
provide a standard wheel washing facility at S8A.
§The Contractor was reminded to
divert the muddy water to a waste water facility for treatment prior to
discharge.
§The Contractor was reminded to
close the gap between silt curtain sections at Portion X.
§The Contractor was reminded to
provide a cover for the rubbish bin at N4.
§The Contractor was reminded to
place sand bags around the gully at N20.
§The Contractor was reminded to provide a drip tray and labels for
chemical containers at N20.
§The Contractor was reminded to
treat the wastewater properly at N4.
§The Contractor was reminded to
provide the sand bags around the gutter to prevent washing away of silt/sand
into the drainage system at N20.
§The Contractor was reminded to
remove the broken water barrier at S7
§The Contractor was reminded to
provide water spray for the breaking activity at S11.
§The Contractor was reminded to fully enclose the cement mixing plant at
S15.
§The Contractor was reminded to
remove the excess rubbish regularly at N1 and S19.
§The Contractor was reminded to
remove the concrete waste at N13.
§The Contractor was reminded to provide
water spraying for the dry unpaved road at S16.
5.2Recommendations
5.2.1The 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.
5.2.2The
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.
5.3.1The construction phase and
EM&A programme of the Contract commenced on 17
October 2012. This is the
tenth Quarterly EM&A
Report which summarises the monitoring results and audit findings of the EM&A programme during the reporting period from 1 December 2014
to 28 February 2015.
Air Quality
5.3.2For AMS5, no Action and Limit Level exceedances
of 1-hr TSP and 24-hr TSP were recorded at
AMS 5 during the reporting period.
5.3.3For AMS6, no Action and Limit Level exceedances of 1-hr TSP level and no Limit Level exceedances of 24-hr TSP were recorded during the reporting
period. An Action Level exceedance of 24-hr TSP level
was recorded on 15 and 27 October 2014, respectively.
Noise
5.3.4For construction noise, there
were no Action Level and Limit Level exceedances
during the reporting period.
Water Quality
5.3.5During the reporting period, nine Action Level exceedances and three Limit Level exceedances
of suspended solid level were recorded. No Action and Limit Level exceedances of dissolved oxygen level were recorded. NoAction and Limit
Level exceedances of turbidity were recorded.
Dolphin
5.3.6There was one Limit Level exceedance of
dolphin monitoring for the quarterly monitoring data (December 2014– February 2015).
5.3.7During this quarter of dolphin
monitoring, no adverse impact from the activities of this construction project
on Chinese White Dolphins was noticeable from general observations.
5.3.8Although 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 in 2012-15, and many individuals have shifted away from the
important habitat around the Brothers Islands.
5.3.9It is critical to 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
5.3.10This measurement result was generally and relatively higher than the
baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously
increased.
5.3.11Impact water quality monitoring in San Tau (monitoring
station SR3) was conducted in December 2014.The monitoring parameters included
dissolved oxygen (DO), turbidity and suspended solids (SS).
Mudflat - Ecology
5.3.12The December 2014 survey was the ninth survey of the EM&A programme during the construction period.Based on the
results, impacts of the HKLR project were not detected on horseshoe crabs and intertidal soft shore community.
It was found that there was a complete
disappearance of seagrassHalophilaovalis in the sampling zone
ST. The combined effects of cyclone hits and turbid water incidence in Sep.
2014 were believed the cause. For the turbid water incidence (i.e. exceedance of SS concentration), there was no evidence
indicating correlation between the turbid water and the contract works of HKLR
(e.g. construction of seawall, stone column works)
as mentioned above. Hence
the negative impact of HKLR project on the seagrass
was not significant. Recently no follow-up action is suggested. In case the
disappearance of seagrass beds Halophilaovalis persists until June 2015, some follow-up
actions should be taken.
Environmental Site Inspection and Audit
5.3.13Environmental site inspection
was carried out on 3, 10, 17, 24 and 30 December 2014, 7, 14, 21 and 30 January 2015 and 4, 11, 17 and 27 February 2015. Recommendations
on remedial actions were given to the Contractors for the deficiencies
identified during the site inspections.
5.3.14There were two environmental
complaints received during the reporting period.
5.3.15No notification of summons and
prosecution was received during the reporting period.
Figures
Appendix A
Environmental Management Structure
Appendix B
Construction Programme
Appendix C
Location of Works Areas
Appendix D
Event and Action Plan
Appendix E
Implementation Schedule of Environmental Mitigation Measures
Appendix F
Site Audit
Findings and Corrective Actions
Appendix G
Air Quality Monitoring Data and Graphical
Plots
Appendix H
Noise Monitoring Data and Graphical Plots
Appendix I
Water Quality Monitoring Data and
Graphical Plots
Appendix J
Dolphin Monitoring Results
Appendix K
Waste Flow Table
Appendix L
Summary of Environmental Licenses and Permits
Appendix M
Record of “Notification of Environmental Quality Limit Exceedances