The Hong Kong-Zhuhai-Macao
Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge
at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB
Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern
waters of the Hong Kong International Airport (HKIA).
The HKLR project has been
separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and Hong
Kong Boundary Crossing Facilities (hereafter referred to as the Contract) and
Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department as the
Contractor to undertake the construction works of Contract No. HY/2011/03.The main works of the Contract include
land tunnel at Scenic Hill, tunnel underneath Airport Road and Airport Express
Line, reclamation and tunnel to the east coast of the Airport Island, at-grade
road connecting to the HKBCF and highway works of the HKBCF within the Airport
Island and in the vicinity of the HKLR reclamation.The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be “Designated Projects”,
under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap
499) and Environmental Impact Assessment (EIA) Reports (Register No.
AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project.The current Environmental Permit (EP)
EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF were issued on 22 December
2014 and 11 April 2016, respectively. These documents are available through the
EIA Ordinance Register. The construction 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 thesixtieth Monthly EM&A report for the Contract which
summarizes the monitoring results and audit findings of the EM&A programme
during the reporting period from 1 to 30 September 2017.
Environmental
Monitoring and Audit Progress
The monthly EM&A
programme was undertaken in accordance with the Updated EM&A Manual for
HKLR (Version 1.0).A summary of
the monitoring activities during this reporting month is listed below:
1-hr TSP
Monitoring
1, 7, 13, 19, 25 and 29 September 2017
24-hr TSP
Monitoring
6,
12, 18, 22, 28 and 30 September 2017
Noise
Monitoring
7, 13, 19 and 25 September 2017
Water Quality
Monitoring
1, 4, 6, 8, 11, 13, 15, 18, 20, 22, 25, 27 and 29 September 2017
Mudflat Monitoring (Ecology)
2, 3, 6, 16 and 17 September 2017
Mudflat Monitoring (Sedimentation Rate)
16 September 2017
Chinese White
Dolphin Monitoring
15, 18, 22 and 29 September 2017
Site
Inspection
6, 13, 20 and 29 September 2017
Due
to the hoisting of Strong Wind Signal and Typhoon Signal No. 3 by the Hong Kong
Observatory, the water quality monitoring at
mid-ebb tide was cancelled on 4 September 2017. No substitute monitoring was
conducted due to boat unavailability.
Due
to bad weather condition, the sedimentation rate monitoring was rescheduled
from 4 September 2017 to 16 September 2017.
Due
to boat unavailability, the dolphin monitoring was rescheduled from 26
September 2017 to 29 September 2017.
Due
to concern of adverse weather forecast in the mid-September 2017, the mudflat
monitoring was rescheduled from 9-12 September 2017 to 6, 16 and 17 September
2017.
Breaches of Action and Limit Levels
A summary of environmental
exceedances for this reporting month is as follows:
Environmental Monitoring
Parameters
Action Level (AL)
Limit Level (LL)
Air Quality
1-hr TSP
0
0
24-hr TSP
0
0
Noise
Leq (30 min)
0
0
Water Quality
Suspended solids level (SS)
1
1
Turbidity level
0
0
Dissolved oxygen level (DO)
0
0
There was an
Action Level exceedance of suspended solid level recorded at station IS(Mf)6
during mid-flood tide on 4 September 2017.
There was a
Limit Level exceedance of suspended solid level recorded at station SR3(N)
during mid-flood tide on 13 September 2017.
Complaint
Log
There was one complaint
received in relation to the environmental impacts during this reporting month.
A summary of environmental complaint for this reporting month is as follows:
Environmental Complaint No.
Date of Complaint Received
Description of Environmental Complaint
COM-2017-102
1823 Integrated Call Centre received
a complaint lodged by a member of the public on 30 September 2017. ET received complaint details on 3 October 2017
Cleanliness problem at Tung Fai Road
For Environmental Complaint
No. COM-2017-102, complaint investigation is being undertaken and will be
reported in next reporting month.
Notifications
of Summons and Prosecutions
There
were no notifications of summons or prosecutions received during this reporting
month.
Reporting
Changes
This report has been
developed in compliance with the reporting requirements for the subsequent
EM&A reports as required by the Updated EM&A Manual for HKLR (Version
1.0).
The proposal for the change
of Action Level and Limit Level for suspended solid and turbidity was approved
by EPD on 25 March 2013.
The revised Event and
Action Plan for dolphin monitoring was approved by EPD on 6 May 2013.
The original monitoring
station at IS(Mf)9 (Coordinate: 813273E, 818850N) was observed inside the
perimeter silt curtain of Contract HY/2010/02 on 1 July 2013, as such the
original impact water quality monitoring location at IS(Mf)9 was temporarily
shifted outside the silt curtain. As advised by the Contractor of HY/2010/02 in
August 2013, the perimeter silt curtain was shifted to facilitate safe
anchorage zone of construction barges/vessels until end of 2013 subject to
construction progress.Therefore,
water quality monitoring station IS(Mf)9 was shifted to 813226E and 818708N
since 1 July 2013.According to the
water quality monitoring team’s observation on 24 March 2014, the original
monitoring location of IS(Mf)9 was no longer enclosed by the perimeter silt
curtain of Contract HY/2010/02. Thus, the impact water quality monitoring works
at the original monitoring location of IS(Mf)9 has been resumed since 24 March
2014.
Transect lines 1, 2, 7, 8,
9 and 11 for dolphin monitoring have been revised due to the obstruction of the
permanent structures associated with the construction works of HKLR and the
southern viaduct of TM-CLKL, as well as provision of adequate buffer distance
from the Airport Restricted Areas.The EPD issued a memo and confirmed that they had no objection on the
revised transect lines on 19 August 2015.
The water quality
monitoring stations at IS10 (Coordinate: 812577E, 820670N) and SR5 (811489E,
820455N) are located inside Hong Kong International Airport (HKIA) Approach
Restricted Areas. The previously granted Vessel's Entry Permit for accessing
stations IS10 and SR5 were expired on 31 December 2016. During the permit
renewing process, the water quality monitoring location was shifted to IS10(N)
(Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E, 820978N) on 2,
4 and 6 January 2017 temporarily. The permit has been granted by Marine
Department on 6 January 2017. Thus, the impact water quality monitoring works
at original monitoring location of IS10 and SR5 has been resumed since 9
January 2017.
Transect lines 2, 3, 4, 5,
6 and 7 for dolphin monitoring have been revised and transect line 24 has been
added due to the presence of a work zone to the north of the airport platform
with intense construction activities in association with the construction of
the third runway expansion for the Hong Kong International Airport. The EPD
issued a memo and confirmed that they had no objection on the revised transect
lines on 28 July 2017. The alternative dolphin transect lines are adopted
starting from August’s dolphin monitoring.
A
new water quality monitoring team has been employed for carrying out water
quality monitoring work for the Contract starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong
International Airport into a Three-Runway System (3RS Project), original
locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed
by works boundary of 3RS Project. Alternative impact water quality monitoring
stations, naming as CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and
were adopted starting from 23 August 2017 to replace the original locations of
water quality monitoring for the Contract.
Water level at water
quality monitoring station SR3 (Coordinate: 810525E, 816456N) is low. As such,
water sampling team members are required to interchange to a smaller boat to
carry out water sampling work, which poses the risk of team members’ falling into
the sea. Due to safety reason, the monitoring station SR3 was relocated to
SR3(N) (Coordinate 816595N, 810689E) on 25 and 28 August 2017 and was
fine-tuned to Coordinate: 816591E, 810689N since 30 August 2017.
Water level at water
quality monitoring station SR4 (Coorinate:814760E, 817867N) is low. The vessel
may ground during navigation in shallow waters, hitting underwater boulder /
obstacles which may jeopardize the safety of all people in the sampling vessel.
Due to safety reason, the monitoring station SR4 was relocated to SR4(N)
(Coordinate: 814705E, 817859N) since 25 August 2017.
Water quality monitoring
station SR10A (823741E, 823495N) locates inside a mariculture raft. Water
sampling team members are required to interchange to a smaller boat to carry
out water sampling work, which poses the risk of team members’ falling into the
sea. Due to safety reason, the monitoring station SR10A was relocated to
SR10A(N) (Coordinate: 823616E, 823487N) on 25 and 28 August 2017 andwasfine-tuned to Coordinate: 823644E and 823484N since
30 August 2017.
Since sampling work is
conducted near rocks in the sea at SR10B (Coordinate: 823686E, 823213N), the
vessel may ground during navigation in shallow waters, hitting underwater
boulder / obstacles which may jeopardize the safety of all people in the
sampling vessel. Due to safety reason, the monitoring station SR10B was
relocated to SR10B(N) (Coordinate: 823683E, 823187N) since 25 August 2017 and
was fine-tuned to SR10B(N2) (Coordinate: 823689E, 823159N) since 11 September
2017.
The relocated stations at
SR3(N), SR4(N) SR10A(N) and SR10B(N)/ SR10B(N2) will
be located to as close to the original sensitive receiver stations as possible.
So, the relocated stations at SR3(N), SR4(N) SR10A(N) and SR10B(N)/
SR10B(N2) are representative. Same baseline and
Action/ Limit Level for water quality monitoring, as derived from the baseline
monitoring data recorded, will be adopted for these alternative water quality
monitoring stations for the Contract.
Water Quality Monitoring
Station SR10A(N) (Coordinate: 823644E, 823484N) was
unreachable on 18 September 2017 during flood tide as fishing activities was
observed in the vicinity of waterbody. Fishing net from a sampan boat blocked
the access to SR10A(N). As such, the water monitoring at station SR10A(N) was
conducted at Coordinate: 823634E, 823631N during flood tide on 18 September
2017.
Water Quality Monitoring
Station CS(Mf)5 (Coordinate: 817990E, 821129N) was unreachable on 20 September
2017 during flood tide due to blockage of access to the station by fishing
boat. Station IS(Mf)6 (Coordinate: 812101E, 817873N) was unreachable on 22 and
27 September 2017 due to blockage of access to the station by working boats.
Water monitoring was conducted at the nearest position of original location of
WQM station to avoid crushing under the effect of water current and wave action
as vessel engine was turned off during sampling. The temporarily relocated
coordinate (i.e. actual coordinate) for Station CS(Mf)5 on 20 September 2017
was 817791E, 821070N. The temporarily relocated coordinates (i.e. actual
coordinates) for Station IS(Mf)6 on 22 and 27 September 2017 was 812150E,
817997N and 812265E, 818156N respectively.
The role and responsibilities as the ET Leader of the
Contract has been temporarily taken up by Mr Willie Wong instead of Ms Claudine
Lee since 25 September 2017.
Future
Key Issues
The future key issues
include potential noise, air quality, water quality and ecological impacts and
waste management arising from the following construction activities to be
undertaken in the upcoming month:
·Stockpiling at WA7;
·Removal of toe loading at Portion X;
Dismantling/trimming
of Temporary 40mm Stone Platform for Construction of Seawall at Portion X;
Construction of Seawall
at Portion X;
Loading and Unloading
Filling Materials at Portion X;
Backfilling at Scenic
Hill Tunnel (Cut & Cover Tunnel) at Portion X;
Excavation for HKBCF
to Airport Tunnel & Construction of Tunnel Box Structure at Portion X;
·Works for Diversion of Airport Road;
Utilities Detection at
Airport Road / Airport Express Line/ East Coast Road;
Establishment of Site
Access at Airport Road / Airport Express Line/East Coast Road;
Excavation and Lateral
Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel West (Cut & Cover Tunnel) at Airport Road;
Excavation and Lateral
Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel East (Cut & Cover Tunnel) at Portion X;
Sub-structure,
Superstructure & Finishing Works for Highway Operation and Maintenance
Area Building at Portion X; and
·Superstructure & Finishing Works
for Scenic Hill Tunnel West Portal Ventilation building at West Portal.
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 Environmental Impact Assessment (EIA) Reports
(Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for the
Project.The current Environmental
Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF were issued on
22 December 2014 and 11 April 2016, respectively. These documents are available
through the EIA Ordinance Register. The construction phase of
Contract was commenced on 17 October 2012.Figure 1.1
shows the project site boundary. The works areas are shown in Appendix O.
1.1.4The Contract includes the
following key aspects:
·New reclamation along the east coast
of the approximately 23 hectares.
·Tunnel of Scenic Hill (Tunnel SHT)
from Scenic Hill to the new reclamation, of approximately 1km in length with
three (3) lanes for the east bound carriageway heading to the HKBCF and four
(4) lanes for the westbound carriageway heading to the HZMB Main Bridge.
·An abutment of the viaduct portion of
the HKLR at the west portal of Tunnel SHT and associated road works at the west
portal of Tunnel SHT.
·An at grade road on the new reclamation
along the east coast of the HKIA to connect with the HKBCF, of approximately
1.6 km along dual 3-lane carriageway with hard shoulder for each bound.
·Road links between the HKBCF and the
HKIA including new roads and the modification of existing roads at the HKIA,
involving viaducts, at grade roads and a Tunnel HAT.
·A highway operation and maintenance
area (HMA) located on the new reclamation, south of the Dragonair Headquarters
Building, including the construction of buildings, connection roads and other
associated facilities.
·Associated civil, structural,
building, geotechnical, marine, environmental protection, landscaping, drainage
and sewerage, tunnel and highway electrical and mechanical works, together with
the installation of street lightings, traffic aids and sign gantries, water
mains and fire hydrants, provision of facilities for installation of traffic
control and surveillance system (TCSS), reprovisioning works of affected
existing facilities, implementation of transplanting, compensatory planting and
protection of existing trees, and implementation of an environmental monitoring
and audit (EM&A) program.
1.1.6BMT 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. Ramboll 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 as follows.
1.2.1The project organization
structure and lines of communication with respect to the on-site environmental
management structure is shown in Appendix A.The key personnel contact names and
numbers are summarized in Table 1.1.
Supervising Officer’s Representative
(Ove Arup & PartnersHong
Kong Limited)
(Chief
Resident Engineer, CRE)
Robert Antony
Evans
3968 0801
2109 1882
Environmental Project Office /
Independent Environmental Checker
(Ramboll Environ Hong Kong Limited)
Environmental Project Office Leader
Y. H. Hui
3465
2888
3465
2899
Independent Environmental Checker
Antony Wong
3465
2888
3465
2899
Contractor
(China State Construction Engineering (Hong Kong) Ltd)
Project Manager
S. Y. Tse
3968
7002
2109
2588
Environmental Officer
Federick Wong
3968
7117
2109
2588
Environmental Team
(BMT Asia Pacific)
Environmental Team Leader
Claudine Lee
2241
9847
2815
3377
Environmental Team
(BMT Asia Pacific)
Deputy Environmental Team Leader
Willie Wong
2241
9821
2815
3377
24
hours complaint hotline
---
---
5699
5730
---
Remark: The
role and responsibilities as the ET Leader of the Contract has been
temporarily taken up by Mr Willie Wong instead of Ms Claudine Lee since 25
September 2017.
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 Month
1.4.1A summary of the construction activities undertaken during this
reporting month is shown inTable 1.2.
Table 1.2Construction
Activities During Reporting Month
Description of Activities
Site Area
Stockpiling
WA7
Dismantling/trimming of temporary 40mm stone platform for construction
of seawall
Portion X
Construction of seawall
Portion X
Loading and unloading of filling materials
Portion X
Backfilling at Scenic Hill Tunnel (Cut & Cover Tunnel)
Portion X
Excavation for HKBCF to Airport Tunnel &
construction of tunnel box structure
Portion X
Works for diversion
Airport Road
Utilities detection
Airport Road/
Airport Express Line/ East Coast Road
Establishment of site access
Airport Road/
Airport Express Line/ East Coast Road
Mined tunnel lining / box jacking transition zone
rebar fixing underneath Airport Road and Airport Express Line
Airport
Road and Airport
Express Line
Construction of Tunnel box structure
Shaft 3
Extension North Shaft
Excavation and lateral support works & Construction of Tunnel Box
Structure for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)
Airport Road
Excavation and lateral support works & construction of tunnel box
structure for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)
Portion X
Sub-structure, superstructure and finishing works for Highway
Operation and Maintenance Area Building
Portion X
Superstructure & finishing works for Scenic Hill Tunnel West
Portal Ventilation building
West Portal
Stockpiling
WA7
Dismantling/trimming of temporary 40mm stone platform for construction
of seawall
Portion X
2Air
Quality Monitoring
2.1Monitoring Requirements
2.1.1In accordance with the Contract Specific
EM&A Manual, baseline 1-hour and 24-hour TSP levels at two air quality
monitoring stations were established.Impact 1-hour TSP monitoring was conducted for at least three times
every 6 days, while impact 24-hour TSP monitoring was carried out for at least
once every 6 days.The Action and
Limit Level for 1-hr TSP and 24-hr TSP are provided in Table 2.1 and Table 2.2,
respectively.
2.2.124-hour
TSP air quality monitoring was performed using High Volume Sampler (HVS)
located at each designated monitoring station. The HVS meets all the
requirements of the Contract Specific EM&A Manual.Portable direct reading dust meters were
used to carry out the 1-hour TSP monitoring.Brand and model of the equipment is
given in Table 2.3.
Table
2.3Air
Quality Monitoring Equipment
Equipment
Brand and
Model
Portable direct reading
dust meter (1-hour TSP)
Sibata Digital Dust
Monitor (Model No. LD-3B)
High Volume Sampler
(24-hour TSP)
Tisch Environmental
Mass Flow Controlled Total Suspended Particulate (TSP) High Volume Air
Sampler (Model No. TE-5170)
(a)The HVS was installed in the vicinity of the air
sensitive receivers. The following criteria were considered in the installation
of the HVS.
(i)A horizontal platform with appropriate support to
secure the sampler against gusty wind was provided.
(ii)The distance between the HVS and any obstacles,
such as buildings, was at least twice the height that the obstacle protrudes
above the HVS.
(iii)A minimum of 2 meters separation from walls,
parapets and penthouse for rooftop sampler was provided.
(iv)No furnace or incinerator flues are nearby.
(v)Airflow around the sampler was unrestricted.
(vi)Permission was obtained to set up the samplers and access
to the monitoring stations.
(vii)A secured supply of electricity was obtained to
operate the samplers.
(viii)The sampler was located more than 20 meters from any
dripline.
(ix)Any wire fence and gate, required to protect the
sampler, did not obstruct the monitoring process.
(x)Flow control accuracy was kept within ±2.5%
deviation over 24-hour sampling period.
(b)Preparation of Filter Papers
(i)Glass fibre filters, G810 were labelled and
sufficient filters that were clean and without pinholes were selected.
(ii)All filters were equilibrated in the conditioning
environment for 24 hours before weighing. The conditioning environment
temperature was around 25 °C
and not variable by more than ±3 °C;
the relative humidity (RH) was < 50% and not variable by more than ±5%.A convenient working RH was 40%.
(iii)All filter papers were prepared and analysed by ALS
Technichem (HK) Pty Ltd., which is a HOKLAS accredited laboratory and has
comprehensive quality assurance and quality control programmes.
(c)Field Monitoring
(i)The power supply was checked to ensure the HVS
works properly.
(ii)The filter holder and the area surrounding the
filter were cleaned.
(iii)The filter holder was removed by loosening the four
bolts and a new filter, with stamped number upward, on a supporting screen was
aligned carefully.
(iv)The filter was properly aligned on the screen so
that the gasket formed an airtight seal on the outer edges of the filter.
(v)The swing bolts were fastened to hold the filter
holder down to the frame.The
pressure applied was sufficient to avoid air leakage at the edges.
(vi)Then the shelter lid was closed and was secured
with the aluminium strip.
(vii)The HVS was warmed-up for about 5 minutes to
establish run-temperature conditions.
(viii)A new flow rate record sheet was set into the flow
recorder.
(ix)On site temperature and atmospheric pressure
readings were taken and the flow rate of the HVS was checked and adjusted at
around 1.1 m3/min, and complied with the range specified in the
Updated EM&A Manual for HKLR (Version 1.0) (i.e. 0.6-1.7 m3/min).
(x)The programmable digital timer was set for a
sampling period of 24 hours, and the starting time, weather condition and the
filter number were recorded.
(xi)The initial elapsed time was recorded.
(xii)At the end of sampling, on site temperature and
atmospheric pressure readings were taken and the final flow rate of the HVS was
checked and recorded.
(xiii)The final elapsed time was recorded.
(xiv)The sampled filter was removed carefully and folded
in half length so that only surfaces with collected particulate matter were in
contact.
(xv)It was then placed in a clean plastic envelope and
sealed.
(xvi)All monitoring information was recorded on a standard
data sheet.
(xvii)Filters were then sent to ALS Technichem (HK) Pty
Ltd. for analysis.
(d)Maintenance and Calibration
(i)The HVS and its accessories were maintained in good
working condition, such as replacing motor brushes routinely and checking
electrical wiring to ensure a continuous power supply.
(ii)5-point calibration of the HVS was conducted using
TE-5025A Calibration Kit
prior to the commencement of baseline monitoring. Bi-monthly 5-point
calibration of the HVS will be carried out during impact monitoring.
(iii)Calibration certificate of the HVSs are provided in
Appendix C.
2.5.21-hour TSP Monitoring
(a)Measuring Procedures
The measuring procedures of
the 1-hour dust meter were in accordance with the Manufacturer’s Instruction
Manual as follows:-
(i)Turn
the power on.
(ii)Close the air collecting opening cover.
(iii)Push the “TIME SETTING” switch to [BG].
(iv)Push “START/STOP” switch to perform background
measurement for 6 seconds.
(v)Turn the knob at SENSI ADJ position to insert the
light scattering plate.
(vi)Leave the equipment for 1 minute upon “SPAN CHECK”
is indicated in the display.
(vii)Push “START/STOP” switch to perform automatic
sensitivity adjustment. This measurement takes 1 minute.
(viii)Pull out the knob and return it to MEASURE
position.
(ix)Push the “TIME SETTING” switch the time set in the
display to 3 hours.
(x)Lower down the air collection opening cover.
(xi)Push “START/STOP” switch to start measurement.
(b)Maintenance
and Calibration
(i)The
1-hour TSP meter was calibrated at 1-year intervals against a Tisch
Environmental Mass Flow Controlled Total Suspended Particulate (TSP) High
Volume Air Sampler. Calibration certificates of the Laser Dust Monitors are
provided in Appendix C.
3.1.1In
accordance with the Contract Specific EM&A Manual, impact noise monitoring
was conducted for at least once per week during the construction phase of the
Project. The Action and Limit level of the noise monitoring is provided in Table 3.1.
Table 3.1Action
and Limit Levels for Noise during Construction Period
Monitoring Station
Time Period
Action Level
Limit Level
NMS5 – Ma Wan
Chung Village (Ma Wan Chung Resident Association) (Tung Chung)
0700-1900
hours on normal weekdays
When one
documented complaint is received
75 dB(A)
3.2Monitoring Equipment
3.2.1Noise
monitoring was performed using sound level meters at each designated monitoring
station.The sound level meters
deployed comply with the International Electrotechnical Commission Publications
(IEC) 651:1979 (Type 1) and 804:1985 (Type 1) specifications.Acoustic calibrator was deployed to
check the sound level meters at a known sound pressure level.Brand and model of the equipment are
given in Table 3.2.
Table 3.2 Noise
Monitoring Equipment
Equipment
Brand and Model
Integrated
Sound Level Meter
B&K 2238
Acoustic
Calibrator
B&K 4231
3.3Monitoring Locations
3.3.1Monitoring
location NMS5 was set
up at the proposed locations in accordance with Contract Specific EM&A
Manual.
3.3.2Figure 2.1 shows the locations
of monitoring stations. Table 3.3
describes the details of the monitoring stations.
Table 3.3Locations
of Impact Noise Monitoring Stations
Monitoring Station
Location
NMS5
Ma Wan Chung
Village (Ma Wan Chung Resident Association) (Tung Chung)
(a)The sound level
meter was set on a tripod at a height of 1.2 m above the podium for free-field measurements at NMS5. A correction of +3 dB(A) shall be made to the
free field measurements.
(b)The battery
condition was checked to ensure the correct functioning of the meter.
(c)Parameters such
as frequency weighting, the time weighting and the measurement time were set as
follows:-
(i)frequency
weighting: A
(ii)time
weighting: Fast
(iii)time
measurement: Leq(30-minutes) during non-restricted hours i.e. 07:00
– 1900 on normal weekdays
(d)Prior to and
after each noise measurement, the meter was calibrated using the acoustic
calibrator for 94.0 dB(A) at 1000 Hz.If the difference in the calibration level before and after measurement
was more than 1.0 dB(A), the measurement would be considered invalid and repeat
of noise measurement would be required after re-calibration or repair of the
equipment.
(e)During the
monitoring period, the Leq, L10 and L90 were
recorded.In addition, site
conditions and noise sources were recorded on a standard record sheet.
(f)Noise
measurement was paused during periods of high intrusive noise (e.g. dog
barking, helicopter noise) if possible. Observations were recorded when
intrusive noise was unavoidable.
(g)Noise monitoring
was cancelled in the presence of fog, rain, wind with a steady speed exceeding 5m/s, or wind with gusts exceeding 10m/s. The wind speed shall be checked with a
portable wind speed meter capable of measuring the wind speed in m/s.
3.5.2Maintenance and Calibration
(a) The
microphone head of the sound level meter was cleaned with soft cloth at regular
intervals.
(b)The
meter and calibrator were sent to the supplier or HOKLAS laboratory to check
and calibrate at yearly intervals.
(c)Calibration
certificates of the sound level meters and acoustic calibrators are provided in
Appendix C.
3.6.1The schedule for construction noise monitoring
in September 2017 is provided in Appendix D.
3.7Monitoring Results
3.7.1The
monitoring results for construction noise are summarized in Table 3.5 and the monitoring results
and relevant graphical plots are provided in Appendix
E.
4.1.1Impact water quality monitoring was carried out
to ensure that any deterioration of water quality is detected, and that timely
action is taken to rectify the situation.For impact water quality monitoring, measurements were taken in
accordance with the Contract Specific EM&A Manual. Table 4.1 shows the established Action/Limit Levels for the
environmental monitoring works.The ET proposed to amend the Acton Level
and Limit Level for turbidity and suspended solid and EPD approved ET’s
proposal on 25 March 2013.Therefore, Action Level and Limit Level for the Contract have been
changed since 25 March 2013.
4.1.2The original and
revised Action Level and Limit Level for turbidity and suspended solid are
shown in Table 4.1.
Table 4.1Action
and Limit Levels for Water Quality
Parameter (unit)
Water Depth
Action Level
Limit Level
Dissolved
Oxygen (mg/L) (surface, middle and bottom)
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.
4.3.1Table 4.3
summarizes the monitoring parameters, frequency and monitoring depths of impact
water quality monitoring as required in the Contract Specific EM&A Manual.
Table 4.3Impact
Water Quality Monitoring Parameters and Frequency
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).
4.4.1In
accordance with the Contract Specific EM&A Manual, thirteen stations (6 Impact Stations, 5 Sensitive Receiver Stations and 2 Control Stations) were designated for
impact water quality monitoring.The six
Impact Stations (IS) were chosen on the basis of their proximity to the
reclamation and thus the greatest potential for water quality impacts, the five Sensitive Receiver Stations (SR) were
chosen as they are close to the key sensitive receives and the two Control
Stations (CS) were chosen to facilitate comparison of the water quality of the
IS stations with less influence by the Project/ ambient water quality
conditions.
4.4.2Due to
safety concern and topographical condition of the original locations of SR4 and
SR10B, alternative impact water quality monitoring stations, naming as SR4(N)
and SR10B(N), were adopted
for Contract No. HY/2010/02, which are situated in vicinity of the original
impact water quality monitoring stations (SR4 and SR10B) and could be
reachable.
4.4.3A new
water quality monitoring team has been employed for carrying out water quality
monitoring work for the Contract starting from 23 August 2017. Due to
marine work of the Expansion of Hong Kong International Airport into a
Three-Runway System (3RS Project), original locations of water quality
monitoring stations CS2, SR5 and IS10 are enclosed by works boundary of 3RS
Project. Alternative impact water quality monitoring stations, naming as
CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and were adopted
starting from 23 August 2017 to replace the original locations of water quality
monitoring for the Contract.
4.4.4Water
level at water quality monitoring station SR3 (Coordinate: 810525E, 816456N) is
low. As such, water sampling team members are required to interchange to a
smaller boat to carry out water sampling work, which poses the risk of team
members’ falling into the sea. Due to safety reason, the monitoring station SR3
was relocated to SR3(N) (Coordinate 816595E, 810689N,) on 25 and 28 August 2017
and was fine-tuned to Coordinate: 816591E, 810689N since 30 August 2017.
4.4.5Water
level at water quality monitoring station SR4 (Coorinate:814760E, 817867N) is
low. The vessel may ground during navigation in shallow waters, hitting
underwater boulder / obstacles which may jeopardize the safety of all people in
the sampling vessel. Due to safety reason, the monitoring station SR4 was relocated
to SR4(N) (Coordinate: 814705E, 817859N) since 25 August 2017.
4.4.6Water
quality monitoring station SR10A (823741E, 823495N) locates inside a
mariculture raft. Water sampling team members are required to interchange to a
smaller boat to carry out water sampling work, which poses the risk of team
members’ falling into the sea. Due to safety reason, the monitoring station
SR10A was relocated to SR10A(N) (Coordinate: 823616E, 823487N) on 25 and 28
August 2017 and was fine-tuned to Coordinate: 823644E and 823484N since 30
August 2017.
4.4.7Since sampling work is conducted near rocks in
the sea at SR10B (Coordinate: 823686E, 823213N), the vessel may ground during
navigation in shallow waters, hitting underwater boulder / obstacles which may
jeopardize the safety of all people in the sampling vessel. Due to safety
reason, the monitoring station SR10B was relocated to SR10B(N) (Coordinate:
823683E, 823187N) since 25 August 2017 and was fine-tuned to SR10B(N2)
(Coordinate: 823689E,
823159N) since 11 September 2017.
4.4.8The
relocated stations at SR3(N), SR4(N) SR10A(N) and SR10B(N)/ SR10B(N2) will be
located to as close to the original sensitive receiver stations as possible.
So, the relocated stations at SR3(N), SR4(N) SR10A(N) and SR10B(N)/ SR10B(N2)
are representative. Same baseline and Action/ Limit Level for water quality
monitoring, as derived from the baseline monitoring data recorded, will be
adopted for these alternative water quality monitoring stations for the
Contract.
4.4.9Water
Quality Monitoring Station SR10A(N) (Coordinate: 823644E, 823484N) was
unreachable on 18 September 2017 during flood tide as fishing activities was
observed in the vicinity of waterbody. Fishing net from a sampan boat blocked
the access to SR10A(N). As such, the water monitoring at station SR10A(N) was
conducted at Coordinate: 823634E, 823631N during flood tide on 18 September
2017.
4.4.10Water
Quality Monitoring Station CS(Mf)5 (Coordinate: 817990E, 821129N) was
unreachable on 20 September 2017 during flood tide due to blockage of access to
the station by fishing boat. Station IS(Mf)6 (Coordinate: 812101E, 817873N) was
unreachable on 22 and 27 September 2017 due to blockage of access to the
station by working boats. Water monitoring was conducted at the nearest
position of original location of WQM station to avoid crushing under the effect
of water current and wave action as vessel engine was turned off during
sampling. The temporarily relocated coordinate (i.e. actual coordinate) for
Station CS(Mf)5 on 20 September 2017 was 817791E, 821070N. The temporarily
relocated coordinates (i.e. actual coordinates) for Station IS(Mf)6 on 22 and
27 September 2017 was 812150E, 817997N and 812265E, 818156N respectively.
4.4.11The
temporarily relocated location were located to as
close to the original location as possible. Also, the water body at
original location of WQM stations and temporarily relocated location of WQM
stations are similar.
So, temporarily relocated location of SR10(A), CS(Mf)5 and IS(MF)6 are
representative. Same baseline and Action/ Limit Level for water quality
monitoring, as derived from the baseline monitoring data recorded, will be
adopted for these temporarily relocated location of SR10(A), CS(Mf)5 and
IS(MF)6 for the Contract.
4.4.12The
locations of water quality monitoring stations during the reporting period are
summarized in Table 4.4 and shown in
Figure 2.1.
Table 4.4 Impact
Water Quality Monitoring Stations
Monitoring Stations
Description
Coordinates
Easting
Northing
IS5
Impact Station
(Close to HKLR construction site)
811579
817106
IS(Mf)6
Impact Station
(Close to HKLR construction site)
812101
817873
IS7
Impact Station
(Close to HKBCF construction site)
812244
818777
IS8
Impact Station
(Close to HKBCF construction site)
814251
818412
IS(Mf)9
Impact Station
(Close to HKBCF construction site)
813273
818850
IS10(N)
Impact Station
(Close to HKBCF construction site)
812942
820881
SR3(N)
Sensitive
receivers (San Tau SSSI)
810689
816591
SR4(N)
Sensitive
receivers (Tai Ho Inlet)
814705
817859
SR5(N)
Sensitive
receivers (Artificial Reef In NE Airport)
812569
821475
SR10A(N)
Sensitive
receivers (Ma Wan Fish Culture Zone)
823644
823484
SR10B(N)
Sensitive
receivers (Ma Wan Fish Culture Zone)
823683
823187
SR10B(N2)
Sensitive
receivers (Ma Wan Fish Culture Zone)
823689
823159
CS2(A)
Control
Station (Mid-Ebb)
805232
818606
CS(Mf)5
Control
Station (Mid-Flood)
817990
821129
Remarks:
1) Due to safety reason,
the monitoring station SR10B was relocated to SR10B(N) (Coordinate: 823683E,
823187N) since 25 August 2017 and was fine-tuned to SR10B(N2) (Coordinate: 823689E,
823159N) since 11 September 2017.
2) Water Quality Monitoring Station SR10A(N)
(Coordinate: 823644E, 823484N) was unreachable on 18 September 2017 during
flood tide as fishing activities was observed in the vicinity of waterbody.
Fishing net from a sampan boat blocked the access to SR10A(N). As such, the
water monitoring at station SR10A(N) was temporarily conducted at Coordinate:
823634E, 823631N during flood tide on 18 September 2017.
3) Water Quality Monitoring Station CS(Mf)5
(Coordinate: 817990E, 821129N) was unreachable on 20 September 2017 during
flood tide due to blockage of access to the station by fishing boat. Station
IS(Mf)6 (Coordinate: 812101E, 817873N) was unreachable on 22 and 27 September
2017 due to blockage of access to the station by working boats.The temporarily relocated coordinate
(i.e. actual coordinate) for Station CS(Mf)5 on 20 September 2017 was
817791E, 821070N. The temporarily relocated coordinates (i.e. actual
coordinates) for Station IS(Mf)6 on 22 and 27 September 2017 was 812150E,
817997N and 812265E, 818156N respectively.
4.5Monitoring Methodology
4.5.1Instrumentation
(a)The
in-situ water quality parameters including dissolved oxygen, temperature,
salinity and turbidity, pH were measured by multi-parameter meters.
4.5.2Operating/Analytical
Procedures
(a)Digital Differential Global Positioning
Systems (DGPS) were used to ensure that the correct location was selected prior
to sample collection.
(b)Portable, battery-operated echo sounders
were used for the determination of water depth at each designated monitoring
station.
(c)All in-situ measurements were taken at 3
water depths, 1 m below water surface, mid-depth and 1 m above sea bed, except
where the water depth was less than 6 m, in which case the mid-depth station was
omitted. Should the water depth be less than 3 m, only the mid-depth station
was monitored.
(d)At each measurement/sampling depth, two
consecutive in-situ monitoring (DO concentration and saturation, temperature,
turbidity, pH, salinity) and water sample for SS. The probes were retrieved out
of the water after the first measurement and then re-deployed for the second
measurement. Where the difference in the value between the first and second
readings of DO or turbidity parameters was more than 25% of the value of the
first reading, the reading was discarded and further readings were taken.
(e)Duplicate samples from each independent
sampling event were collected for SS measurement. Water samples were collected
using the water samplers and the samples were stored in high-density polythene
bottles. Water samples collected were well-mixed in the water sampler prior to
pre-rinsing and transferring to sample bottles. Sample bottles were pre-rinsed
with the same water samples. The sample bottles were then be packed in
cool-boxes (cooled at 4oC without being frozen), and delivered to
ALS Technichem (HK) Pty Ltd. for the analysis of suspended solids
concentrations. The laboratory determination work would be started within 24
hours after collection of the water samples. ALS Technichem (HK) Pty Ltd. is a
HOKLAS accredited laboratory and has comprehensive quality assurance and
quality control programmes.
(f)The analysis method and detection limit for
SS is shown in Table 4.5.
Table
4.5Laboratory Analysis
for Suspended Solids
Parameters
Instrumentation
Analytical Method
Detection Limit
Suspended
Solid (SS)
Weighting
APHA 2540-D
0.5mg/L
(g)Other relevant data were recorded, including
monitoring location / position, time, water depth, tidal stages, weather
conditions and any special phenomena or work underway at the construction site
in the field log sheet for information.
4.5.3Maintenance
and Calibrations
(a)All in situ monitoring instruments would be
calibrated by ALS Technichem (HK) Pty Ltd. before use and at 3-monthly
intervals throughout all stages of the water quality monitoring programme. The
procedures of performance check of sonde and testing results are provided in Appendix C.
4.6.1The schedule for impact water quality monitoring
in September 2017 is provided in Appendix D.
4.7Monitoring Results
4.7.1Impact
water quality monitoring was conducted at all designated monitoring stations
during the reporting month. Impact water quality monitoring results and
relevant graphical plots are provided inAppendix
E.
4.7.2Water
quality impact sources during water quality monitoring were the construction
activities of the Contract, nearby construction activities by other parties and
nearby operating vessels by other parties.
4.7.3For marine water quality monitoring, no Action Level and Limit
Level exceedances of dissolved oxygen and
turbidity level were recorded during the reporting month. There were one Action
Level and one Limit Level exceedances of suspended solids level were recorded
during the reporting month. Number of
exceedances recorded during the reporting month at each impact station are
summarised in Table 4.6.
Table 4.6Summary 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
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS(Mf)6
Action Level
--
--
--
--
--
--
--
4
Sep 2017
0
1
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
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS10(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR3(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
13
Sep 2017
0
1
SR4(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR5(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR10A(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR10B(N2)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
Total
Action
0
0
0
0
0
0
0
1
1**
Limit
0
0
0
0
0
0
0
1
1**
Notes:
S: Surface;
M: Mid-depth;
**The total number of exceedances
4.7.4For marine water quality monitoring, an Action
Level exceedance of suspended solid was recorded at station IS(Mf)6 during
mid-flood tide on 4 September 2017. Removal of surcharge at Zone 1; road and
drainage construction at Zones 1 and 2; box culvert construction at Zone 2;
seawall construction at Zones 2 and 3; and transportation of fill material at
Zone 3 were carried out within the properly deployed silt curtain as
recommended in the EIA Report. There was no marine transportation at Zones 1,
2, and 3. There were no specific activities recorded during the monitoring
period that would cause any significant impacts on the monitoring results.
Also, there was no muddy plume observed at station IS(Mf)6 during sampling
exercise. In addition, no leakage of turbid water, abnormity or malpractice for
the contract works was observed during the sampling exercise.
4.7.5On 13 September 2017, a Limit Level exceedance of
suspended solid was recorded at station SR3(N) during mid-flood tide.Removal of surcharge,
road and drainage construction at Zone 1; box culvert construction at Zone 2;
seawall construction at Zones 2 and 3; and transportation of fill material at
Zone 3 were carried out within the properly deployed silt curtain as
recommended in the EIA Report.There was no marine transportation at Zones
1, 2, and 3. There were no specific activities recorded during the monitoring
period that would cause any significant impacts on the monitoring results.
Also, there was no muddy plume observed at station SR3(N) during sampling
exercise. In addition, no leakage of turbid water, abnormity or
malpractice for the contract works was observed during the sampling exercise.
4.7.6The exceedances of suspended solids
level recorded during reporting period were considered to be attributed to
other external factors such as sea condition, rather than the contract works.
Therefore, the exceedances were considered as non-contract related. Records
of “Notification of Environmental Quality Limit Exceedances” are provided in Appendix N.
4.7.7The
event action plan is annexed in Appendix F.
5.1.1Impact dolphin monitoring is required to be conducted by a qualified dolphin
specialist team to evaluate whether there have been any effects on the dolphins.
5.1.2The Action
Level and Limit Level for dolphin monitoring are shown in Table 5.1.
Table 5.1Action
and Limit Levels for Dolphin Monitoring
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 encounter rate of number of dolphin sightings.
2.ANI means quarterly 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.
5.1.3The
revised Event and Action Plan for dolphin Monitoring was approved by EPD in 6
May 2013. The revised Event and Action Plan is
annexed in Appendix F.
5.2.1According to the requirement of the updated EM&A manual, dolphin
monitoring programme should cover all transect lines in NEL and NWL survey
areas (see Figure 1 of Appendix H) twice per month throughout the entire construction period.The co-ordinates of all transect lines
are shown in Table 5.2.The
coordinates of several starting and ending points have been revised due to the presence
of a work zone to the north of the airport platform with intense construction
activities in association with the construction of the third runway expansion
for the Hong Kong International Airport.The EPD issued a memo and confirmed that they had no objection on the
revised transect lines on 28 July 2017, and the revised coordinates are in red
and marked with an asterisk in Table 5.2.
Table 5.2Co-ordinates
of Transect Lines
Line No.
Easting
Northing
Line No.
Easting
Northing
1
Start Point
804671
815456
13
Start Point
816506
819480
1
End Point
804671
831404
13
End Point
816506
824859
2
Start Point
805476
820800*
14
Start Point
817537
820220
2
End Point
805476
826654
14
End Point
817537
824613
3
Start Point
806464
821150*
15
Start Point
818568
820735
3
End Point
806464
822911
15
End Point
818568
824433
4
Start Point
807518
821500*
16
Start Point
819532
821420
4
End Point
807518
829230
16
End Point
819532
824209
5
Start Point
808504
821850*
17
Start Point
820451
822125
5
End Point
808504
828602
17
End Point
820451
823671
6
Start Point
809490
822150*
18
Start Point
821504
822371
6
End Point
809490
825352
18
End Point
821504
823761
7
Start Point
810499
822000*
19
Start Point
822513
823268
7
End Point
810499
824613
19
End Point
822513
824321
8
Start Point
811508
821123
20
Start Point
823477
823402
8
End Point
811508
824254
20
End Point
823477
824613
9
Start Point
812516
821303
21
Start Point
805476
827081
9
End Point
812516
824254
21
End Point
805476
830562
10
Start Point
813525
821176
22
Start Point
806464
824033
10
End Point
813525
824657
22
End Point
806464
829598
11
Start Point
814556
818853
23
Start Point
814559
821739
11
End Point
814556
820992
23
End Point
814559
824768
12
Start Point
815542
818807
24*
Start
Point
805476*
815900*
12
End Point
815542
824882
24*
End
Point
805476*
819100*
Note:
Co-ordinates in red and marked with asterisk are revised co-ordinates of
transect line.
5.2.2The survey team used standard line-transect methods
(Buckland et al. 2001) to conduct the systematic vessel surveys, and followed
the same technique of data collection that has been adopted over the last 18
years of marine mammal monitoring surveys in Hong Kong developed by HKCRP (see
Hung 2015).For each monitoring
vessel survey, a 15-m inboard vessel with an open upper deck (about 4.5 m above
water surface) was used to make observations from the flying bridge area.
5.2.3Two experienced observers (a data recorder and a
primary observer) made up the on-effort survey team, and the survey vessel
transited different transect lines at a constant speed of 13-15 km per
hour.The data recorder searched
with unaided eyes and filled out the datasheets, while the primary observer
searched for dolphins and porpoises continuously through 7 x 50 Fujinon marine binoculars.Both observers searched the sea ahead of
the vessel, between 270o and 90o (in relation to the bow,
which is defined as 0o).One to two additional experienced observers were available on the boat
to work in shift (i.e. rotate every 30 minutes) in order to minimize fatigue of
the survey team members.All
observers were experienced in small cetacean survey techniques and identifying
local cetacean species.
5.2.4During on-effort
survey periods, the survey team recorded effort data including time, position
(latitude and longitude), weather conditions (Beaufort sea state and
visibility), and distance traveled in each series (a continuous period of
search effort) with the assistance of a handheld GPS (Garmin eTrex Legend).
5.2.5Data including time, position and vessel speed were
also automatically and continuously logged by handheld GPS throughout the
entire survey for subsequent review.
5.2.6When dolphins were sighted, the survey team would
end the survey effort, and immediately record the initial sighting distance and
angle of the dolphin group from the survey vessel, as well as the sighting time
and position.Then the research
vessel was diverted from its course to approach the animals for species
identification, group size estimation, assessment of group composition, and
behavioural observations.The
perpendicular distance (PSD) of the dolphin group to the transect line was
later calculated from the initial sighting distance and angle.
5.2.7Survey effort being conducted along the parallel
transect lines that were perpendicular to the coastlines (as indicated in Figure 1 of Appendix H) was labeled as
“primary” survey effort, while the survey effort conducted along the connecting
lines between parallel lines was labeled as “secondary” survey effort.According to HKCRP long-term dolphin
monitoring data, encounter rates of Chinese white dolphins deduced from effort
and sighting data collected along primary and secondary lines were similar in
NEL and NWL survey areas.Therefore, both primary and secondary survey effort were presented as
on-effort survey effort in this report.
5.2.8Encounter rates of Chinese white dolphins (number
of on-effort sightings per 100 km of survey effort and number of dolphins from
all on-effort sightings 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.Only data collected under Beaufort 3 or below condition would be used
for encounter rate analysis.Dolphin encounter rates were calculated using primary survey effort
alone, as well as the combined survey effort from both primary and secondary
lines.
Photo-identification Work
5.2.9When a group of Chinese White Dolphins were sighted
during the line-transect survey, the survey team would end effort and approach
the group slowly from the side and behind to take photographs of them.Every attempt was made to photograph
every dolphin in the group, and even photograph both sides of the dolphins,
since the colouration and markings on both sides may not be symmetrical.
5.2.10A professional digital camera (Canon EOS 7D or 60D model), equipped with long telephoto lenses (100-400
mm zoom), were available on board for researchers to take sharp, close-up
photographs of dolphins as they surfaced.The images were shot at the highest available resolution and stored on
Compact Flash memory cards for downloading onto a computer.
5.2.11All digital images taken in the field were first
examined, and those containing potentially identifiable individuals were sorted
out.These photographs would then
be examined in greater detail, and were carefully compared to the existing
Chinese White Dolphin photo-identification catalogue maintained by HKCRP since
1995.
5.2.12Chinese White
Dolphins can be identified by their natural markings, such as nicks, cuts,
scars and deformities on their dorsal fin and body, and their unique spotting
patterns were also used as secondary identifying features (Jefferson 2000).
5.2.13All photographs of
each individual were then compiled and arranged in chronological order, with
data including the date and location first identified (initial sighting),
re-sightings, associated dolphins, distinctive features, and age classes
entered into a computer database.Detailed information on all identified individuals will be further
presented as an appendix in quarterly EM&A reports.
5.3.1During
the month of September 2017, two sets of systematic line-transect vessel
surveys were conducted on the 15th, 18th 22nd
and 29th to cover all transect lines in NWL and NEL survey areas
twice.The survey routes of each
survey day are presented in Figures 2 to
5 of Appendix H.
5.3.2From
these surveys, a total of 266.33 km of survey effort was collected, with 97.9%
of the total survey effort being conducted under favourable weather conditions
(i.e. Beaufort Sea State 3 or below with good visibility) (Annex I of Appendix H).Among the two areas, 96.80 km and 169.53 km of survey effort were
collected from NEL and NWL survey areas respectively.Moreover, the total survey effort
conducted on primary lines was 195.67 km, while the effort on secondary lines
was 70.66 km.
5.3.3During
the two sets of monitoring surveys in September 2017, three groups of 11
Chinese White Dolphins were sighted (see Annex
II of Appendix H).All dolphin
sightings were made in NWL, while none was sighted in NEL.Moreover, all three dolphin groups were
sighted during on-effort search and on primary lines (Annex II of Appendix H).None of the dolphin groups were associated with any operating fishing
vessel.
5.3.4Distribution
of the three dolphin sightings made in September 2017 is shown in Figure 6 of Appendix H.The three groups were sighted near
Castle Peak Power Station, to the north of Lung Kwu Chau and to the east of Sha
Chau respectively (Figure 6 of Appendix
H).On the other hand, all
dolphin groups were sighted far away from the HKLR03/HKBCF reclamation sites as
well as the HKLR09/TMCLKL alignments (Figure
6 of Appendix H).
5.3.5Notably,
the two dolphin groups were sighted far away from
the HKLR03/ HKBCF reclamation sites as well as the HKLR09/TMCLKL alignments (Figure
6 of Appendix H).
5.3.6During the
September’s surveys, encounter rates of Chinese White Dolphins deduced from the
survey effort and on-effort sighting data made under favourable conditions
(Beaufort 3 or below) are shown in Tables
5.3 and 5.4.
Table 5.3Individual
Survey Event Encounter Rates
Encounter rate (STG)
(no. of on-effort
dolphin sightings per 100 km of survey effort)
Encounter rate (ANI)
(no. of dolphins from
all on-effort sightings per 100 km of survey effort)
Primary Lines Only
Primary Lines Only
NEL
Set 1: September 15th / 18th
0.0
0.0
Set 2: September 22nd / 29th
0.0
0.0
NWL
Set 1: September 15th / 18th
0.0
0.0
Set 2: September 22nd / 29th
3.6
16.3
Remark:
1.Dolphin Encounter Rates Deduced from the Two
Sets of Surveys (Two Surveys in Each Set) in September 2017 in
Northeast Lantau (NEL) and Northwest Lantau (NWL).
Table 5.4Monthly
Average Encounter Rates
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)
PrimaryLines Only
Both Primary and
Secondary Lines
PrimaryLines Only
Both Primary and
Secondary Lines
Northeast Lantau
0.0
0.0
0.0
0.0
Northwest Lantau
1.7
1.2
7.7
5.5
Remark:
1.Monthly Average Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) from All Four Surveys
Conducted in September 2017 on Primary Lines only as well as Both Primary
Lines and Secondary Lines in Northeast Lantau (NEL) and Northwest Lantau (NWL).
5.3.7The
average dolphin group size in September 2017 was 3.7 individuals per group. Two
of the three groups were small in sizes (i.e. 2-3 animals per group), while the
other group was medium in size with six animals (Annex II of Appendix H).
Photo-identification Work
5.3.8Eight known individual dolphins were sighted 10
times during September’s surveys (Annexes
III and IV of Appendix H).All
except two individuals (i.e. NL202 and NL286 being re-sighted twice) were
re-sighted only once during the monthly surveys in September 2017.
5.3.9Notably, one of these individuals (NL202) was
sighted with her older calf (NL286) during their re-sightings in September
2017.
Conclusion
5.3.10During
this month of dolphin monitoring, no adverse impact from the activities of this
construction project on Chinese White Dolphins was noticeable from general
observations.
5.3.11Due to
monthly variation in dolphin occurrence within the study area, it would be more
appropriate to draw conclusion on whether any impacts on dolphins have been
detected related to the construction activities of this project in the
quarterly EM&A report, where comparison on distribution, group size and
encounter rates of dolphins between the quarterly impact monitoring period
(September – November 2017) and baseline monitoring period (3-month period)
will be made.
5.4Reference
5.4.1Buckland, S. T., Anderson, D. R., Burnham, K. P.,
Laake, J. L., Borchers, D. L., and Thomas, L.2001.Introduction to distance sampling:
estimating abundance of biological populations.Oxford University Press, London.
5.4.2Hung, S. K.2015.Monitoring of Marine
Mammals in Hong Kong waters: final report (2014-15).An unpublished report submitted to the
Agriculture, Fisheries and Conservation Department, 198 pp.
5.4.3Jefferson,
T. A.2000.Population biology of the Indo-Pacific
hump-backed dolphin in Hong Kong waters.Wildlife Monographs 144:1-65.
6.1.1To avoid
disturbance to the mudflat and nuisance to navigation, no fixed
marker/monitoring rod was installed at the monitoring stations. A high
precision Global Navigation Satellite System (GNSS) real time location fixing
system (or equivalent technology) was used to locate the station in the
precision of 1mm, which is reasonable under flat mudflat topography with uneven
mudflat surface only at micro level.This method has been used on Agricultural Fisheries and Conservation
Department’s (AFCD) project, namely Baseline Ecological Monitoring Programme
for the Mai Po Inner Deep Bay Ramsar Site for measurement of seabed levels.
6.1.2Measurements
were taken directly on the mudflat surface.The Real Time Kinematic GNSS (RTK GNSS)
surveying technology was used to measure mudflat surface levels and 3D
coordinates of a survey point.The
RTK GNSS survey was calibrated against a reference station in the field before
and after each survey.The
reference station is a survey control point established by the Lands Department
of the HKSAR Government or traditional land surveying methods using
professional surveying instruments such as total station, level and/or geodetic
GNSS.The coordinates system was in
HK1980 GRID system.For this
contract, the reference control station was surveyed and established by
traditional land surveying methods using professional surveying instruments
such as total station, level and RTK GNSS.The accuracy was down to mm level so that the reference control station
has relatively higher accuracy.As
the reference control station has higher accuracy, it was set as true
evaluation relative to the RTK GNSS measurement.All position and height correction were
adjusted and corrected to the reference control station.Reference station survey result and
professional land surveying calibration is shown as Table 6.1:
Table 6.1Reference
Station Survey result and GNSS RTK calibration result of Round 1
Reference Station
Easting (m)
Northing (m)
Baseline reference elevation (mPD) (A)
Round 1 Survey (mPD) (B)
Calibration Adjustment (B-A)
T1
811248.660mE
816393.173mN
3.840
3.817
-0.023
T2
810806.297mE
815691.822mN
4.625
4.653
+0.028
T3
810778.098mE
815689.918mN
4.651
4.660
+0.009
T4
810274.783mE
816689.068mN
2.637
2.709
+0.072
6.1.3The
precision of the measured mudflat surface level reading (vertical precision
setting) was within 10 mm (standard deviation) after averaging the valid survey
records of the XYZ HK1980 GRID coordinates.Each survey record at each station was
computed by averaging at least three measurements that are within the above
specified precision setting. Both digital data logging and written records were
collected in the field.Field data
on station fixing and mudflat surface measurement were recorded.
Monitoring Locations
6.1.4Four
monitoring stations were established based on the site conditions for the
sedimentation monitoring and are shown in Figure 6.1.
Monitoring Results
6.1.5The
baseline sedimentation rate monitoring was in September 2012 and impact
sedimentation rate monitoring was undertaken on 16 September 2017. The
mudflat surface levels at the four established monitoring stations and the
corresponding XYZ HK1980 GRID coordinates are presented in Table 6.2 and Table 6.3.
Table 6.2Measured
Mudflat Surface Level Results
Baseline Monitoring (September 2012)
Impact Monitoring (September 2017)
Monitoring
Station
Easting
(m)
Northing
(m)
Surface
Level
(mPD)
Easting
(m)
Northing
(m)
Surface
Level
(mPD)
S1
810291.160
816678.727
0.950
810291.088
816678.776
1.088
S2
810958.272
815831.531
0.864
810958.265
815831.586
0.973
S3
810716.585
815953.308
1.341
810716.480
815953.308
1.463
S4
811221.433
816151.381
0.931
811221.423
816151.385
1.085
Table 6.3Comparison
of measurement
Comparison of measurement
Remarks and Recommendation
Monitoring
Station
Easting
(m)
Northing
(m)
Surface
Level
(mPD)
S1
-0.072
0.049
0.138
Level
continuously increased
S2
-0.007
0.055
0.109
Level
continuously increased
S3
-0.105
0.000
0.122
Level
continuously increased
S4
-0.01
0.004
0.154
Level
continuously increased
6.1.6This measurement result was generally and
relatively higher than the baseline measurement at S1, S2, S3 and S4. The
mudflat level is continuously increased.
6.2.1The
mudflat monitoring covered water quality monitoring data.Reference was made to the water quality
monitoring data of the representative water quality monitoring station (i.e.
SR3(N)) as in the EM&A Manual.The water quality monitoring location (SR3(N)) is shown in Figure 2.1.
6.2.2Impact
water quality monitoring in San Tau (monitoring station SR3(N)) was conducted
in September 2017.The monitoring
parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).
6.2.3The
Impact monitoring results for SR3(N) were extracted and summarised below:
Table 6.4Impact
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)
1-Sep-17
6.6
7.4
4.7
6.9
6.0
7.0
4-Sep-17
Remark 1
Remark 1
Remark 1
6.0
8.7
9.7
6-Sep-17
5.5
11.4
9.1
5.5
10.3
9.9
8-Sep-17
6.1
11.4
7.7
5.6
5.7
8.0
11-Sep-17
5.7
6.8
12.1
5.4
5.4
11.3
13-Sep-17
5.2
6.6
6.2
5.8
11.5
38.7
15-Sep-17
6.2
5.4
3.5
6.7
7.8
4.9
18-Sep-17
6.1
3.6
6.4
8.3
6.5
10.1
20-Sep-17
5.9
12.5
19.1
5.9
5.6
11.6
22-Sep-17
11.3
9.3
12.1
5.3
7.5
11.9
25-Sep-17
5.7
5.0
7.8
5.9
5.8
7.7
27-Sep-17
6.6
5.9
8.2
6.0
2.1
5.7
29-Sep-17
5.9
4.3
8.0
8.0
5.5
9.2
Average
6.4
7.5
8.7
6.3
6.8
11.2
Remark:
1) Due to the hoisting of Strong Wind
Signal and Typhoon Signal No. 3 by the Hong Kong Observatory, the water
quality monitoring at mid-ebb tide was cancelled on 4 September 2017. No
substitute monitoring was conducted due to boat unavailability.
6.3.1In
order
to collect baseline information of mudflats in the study site, the study site
was divided into three sampling zones (labeled as TC1, TC2, TC3) in Tung Chung
Bay and one zone in San Tau (labeled as ST) (Figure 2.1 of Appendix I). The horizontal shoreline of sampling
zones TC1, TC2, TC3 and ST were about 250 m, 300 m, 300 m and 250 m
respectively (Figure 2.2 of Appendix I).
Survey of horseshoe crabs, seagrass beds and intertidal communities were conducted
in every sampling zone. The present survey was conducted in September 2017
(totally 5 sampling days between 2nd and 17th September
2017).
6.3.2Since the field survey of Jun. 2016,
increasing number of trashes and even big trashes (Figure 2.3 of Appendix I) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Wan. Respective measures (e.g. manual clean-up) should be
implemented by responsible units.
Horseshoe Crabs
6.3.3Active search
method was conducted for horseshoe crab monitoring by two experienced surveyors
in every sampling zone. During the search period, any accessible and potential
area would be investigated for any horseshoe crab individuals within 2-3 hours
of low tide period (tidal level below 1.2 m above Chart Datum (C.D.)). Once a
horseshoe crab individual was found, the species was identified referencing to
Li (2008). The prosomal width, inhabiting substratum and respective GPS
coordinate were recorded. A photographic record was taken for future
investigation. Any grouping behavior of individuals, if found, was recorded.
The horseshoe crab surveys were conducted on 2nd (for TC2), 3rd (for
TC1) and 6th (for TC3 and ST) September 2017. The weather was
generally hot on all field days without rainfall.
In Jun. 2017, a
big horseshoe crab was tangled by a trash gill net in ST mudflat (Figure 2.3 of Appendix I). It was
released to sea once after photo recording. The horseshoe crab of such size
should be inhabitating sub-tidal environment while it forages on intertidal
shore occasionally during high tide period. If it is tangled by the trash net
for few days, it may die due to starvation or overheat during low tide period.
These trash gill nets are definitely ‘fatal trap’ for the horseshoe crabs and
other marine life. Manual clean-up should be implemented as soon as possible by
responsible units.
Seagrass Beds
6.3.4Active search
method was conducted for seagrass bed monitoring by two experienced surveyors
in every sampling zone. During the search period, any accessible and potential
area would be investigated for any seagrass beds within 2-3 hours of low tide
period. Once seagrass bed was found, the species, estimated area, estimated
coverage percentage and respective GPS coordinates were recorded. The seagrass
beds surveys were conducted on 2nd (for TC2), 3rd (for
TC1) and 6th (for TC3 and ST) September 2017. The weather was
generally hot on all field days without rainfall.
Intertidal Soft Shore Communities
6.3.5The intertidal soft shore community surveys were
conducted in low tide period on 2nd (for TC2), 3rd (for TC1), 16th
(for TC3) and 17th (for ST) September 2017. In every sampling zone,
three 100m horizontal transect lines were laid at high tidal level (H: 2.0 m
above C.D.), mid tidal level (M: 1.5 m above C.D.) and low tidal level (L: 1.0
m above C.D.). Along every horizontal transect line, ten random quadrats (0.5 m
x 0.5 m) were placed.
6.3.6Inside a quadrat, any visible epifauna were
collected and were in-situ identified to the lowest practical taxonomical
resolution. Whenever possible a hand core sample (10 cm internal diameter ´ 20 cm depth) of
sediments was collected in the quadrat. The core sample was gently washed
through a sieve of mesh size 2.0 mm in-situ. Any visible infauna were collected
and identified. Finally the top 5 cm surface sediments was dug for visible
infauna in the quadrat regardless of hand core sample was taken.
6.3.7All
collected fauna were released after recording except some tiny individuals that
are too small to be identified on site. These tiny individuals were taken to
laboratory for identification under dissecting microscope.
6.3.8The 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
6.3.9Data 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.
6.4.1In the event of the impact monitoring results
indicating that the density or the distribution pattern of intertidal fauna and
seagrass is found to be significant different to the baseline condition (taking
into account natural fluctuation in the occurrence and distribution pattern
such as due to seasonal change), appropriate actions should be taken and
additional mitigation measures should be implemented as necessary.Data should then be re-assessed and the
need for any further monitoring should be established.The action plan, as given in Table 6.5 should be undertaken within a
period of 1 month after a significant difference has been determined.
Table
6.5Event and
Action Plan for Mudflat Monitoring
Event
ET Leader
IEC
SO
Contractor
Density or the distribution
pattern of horseshoe crab, seagrass or intertidal soft shore communities
recorded in the impact or post-construction monitoring aresignificantly lower than or different
from those recorded in the baseline monitoring.
Review historical data
to ensure differences are as a result of natural variation or previously
observed seasonal differences;
Identify source(s) of
impact;
Inform the IEC, SO and
Contractor;
Check monitoring data;
Discuss additional monitoring
and any other measures, with the IEC and Contractor.
Discuss monitoring with
the ET and the Contractor;
Review proposals for
additional monitoring and any other measures submitted by the Contractor and
advise the SO accordingly.
Discuss with the IEC
additional monitoring requirements and any other measures proposed by the ET;
Make agreement on the
measures to be implemented.
Inform the SO and in
writing;
Discuss with the ET and
the IEC and propose measures to the IEC and the ER;
6.5.1In the present survey, two species of horseshoe
crab Carcinoscorpius rotundicauda
(total 130 ind.) and Tachypleus
tridentatus (total 77 ind.) were recorded. For one sight record, grouping
of 2-18 individuals was observed at same locations with similar substratum
(fine sand or soft mud, slightly submerged). Photo records were shown in Figure 3.1 of Appendix
I while the complete survey records were listed in Annex II of Appendix I.
6.5.2Table
3.1 of Appendix I
summarizes the survey results of horseshoe crab in the present survey. For Carcinoscorpius rotundicauda, moderate
number of individuals (18 ind.) were found in TC1 that search record was at
low-moderate level (4.5 ind. hr-1 person-1). The average
body size was 30.91 mm (prosomal width ranged 19.99-47.55 mm) in TC1. There was
one individual found in TC2 only (prosomal width 37.85 mm) resulting in very
low search record (0.3 ind. hr-1 person-1). More
individuals were found in TC3 (72 ind.) and ST (39 ind.) resulting in
relatively higher search records (6.5-12.0 ind. hr-1 person-1).
Smaller individuals were found in TC3 that the average body size was 35.02 mm
(prosomal width ranged 13.30-80.27 mm). The average body size was 50.18 mm
(prosomal width ranged 19.87-78.00 mm) in ST.
6.5.3For Tachypleus tridentatus, there was one
individual found in TC1 only (prosomal width 38.34 mm) resulting in very low
search record (0.3 ind. hr-1 per son-1). No individual was found in TC2.
Similarly, more individuals were found in TC3 (48 ind.) and ST (28 ind.)
respectively. In TC3, the search record was relatively higher (8.0 ind. hr-1
person-1) while the average body size was 47.52 mm (prosomal width ranged
34.76-88.93 mm). In ST, the search record was 4.7 ind. hr-1 person-1
while the average body size was 47.21 mm (prosomal width ranged 29.61-64.36
mm).
6.5.4In the previous
survey of Mar. 2015, there was one important finding that a mating pair of Carcinoscorpius rotundicauda was found
in ST (prosomal width: male 155.1 mm, female 138.2 mm) (Figure 3.2 of Appendix I). It indicated the importance of ST as a
breeding ground of horseshoe crab. In another survey of Jun. 2017, mating pairs
of Carcinoscorpius rotundicauda were
also found in TC2 (prosomal width: male 175.27 mm, female 143.51 mm) and TC3
(prosomal width: male 182.08 mm, female 145.63 mm) (Figure 3.2 of Appendix I). It indicated
that breeding of horseshoe crab could occur along the coast of Tung Chung Wan
rather than ST only, as long as suitable substratum was available. The mating
pairs were found nearly burrowing in soft mud at low tidal level (0.5-1.0 m
above C.D.). The smaller male was holding the opisthosoma (abdomen carapace) of
larger female from behind.
6.5.5In the previous
surveys (Jun. 2016, Jun. 2017) and present survey (Sep. 2017), there were
occasional records of large individuals of Carcinoscorpius
rotundicauda (prosomal width ranged 117.37- 178.67 mm, either single or in
pair) in ST (Fig. 3.3). Based on their sizes, it indicated that individuals of
prosomal width larger than 100 mm would progress its nursery stage from
intertidal habitat to sub-tidal habitat of Tung Chung Wan. These large
individuals might move onto intertidal shore occasionally during high tide for
foraging and breeding. Because they should be inhabiting sub-tidal habitat most
of the time. Their records were excluded from the data analysis to avoid mixing
up with juvenile population living on intertidal habitat.
6.5.6No marked
individual of horseshoe crab was recorded in the present survey. Some marked
individuals were found in the previous surveys of Sep. 2013, Mar. 2014 and Sep.
2014. All of them were released through a conservation programme in charged by
Prof. Paul Shin (Department of Biology and Chemistry, The City University of
Hong Kong (CityU)). It was a re-introduction trial of artificial bred horseshoe
crab juvenile at selected sites. So that the horseshoe crab population might be
restored in the natural habitat. Through a personal conversation with Prof.
Shin, about 100 individuals were released in the sampling zone ST on 20 June
2013. All of them were marked with color tape and internal chip detected by
specific chip sensor. There should be second round of release between June and
September 2014 since new marked individuals were found in the survey of Sep.
2014.
6.5.7The
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
6.5.8Figures 3.4 and
3.5 of Appendix I show the changes
of number of individuals, mean prosomal width and search record of horseshoe
crabs Carcinoscorpius rotundicauda
and Tachypleus tridentatus
respectively in every sampling zone throughout the monitoring period.
6.5.9For TC3
and ST, medium to high search records (i.e. number of individuals) of both
species were always found in wet season (Jun. and Sep.). The search record of
ST was higher from Sep. 2012 to Jun. 2014 while it was replaced by TC3 from
Sep. 2014 to Jun. 2015. The search records were similar between two sampling
zones from Sep. 2015 to Jun. 2016. In Sep. 2016, the search record of Carcinoscorpius rotundicauda in ST was
much higher than TC3. From Mar. to Jun. 2017, the search records of both
species were similar again between two sampling zones. It showed a natural
variation of horseshoe crab population in these two zones due to weather
condition and tidal effect. No obvious difference of horseshoe crab population
was noted between TC3 and ST. In Sep. 2017, the search records of both
horseshoe crab species decreased except the Carcinoscorpius
rotundicauda in TC3. The survey results were different from previous
findings that there were usually higher search records in Sep.. One possible
reason was that the serial cyclone hit decreased horseshoe crab activity
(totally 4 cyclone records between Jun. and Sep. 2017, to be discussed in
'Seagrass survey' section).
6.5.10For
TC1, the search record was at low to medium level throughout the monitoring
period. The change of Carcinoscorpius
rotundicauda was relatively more variable than that of Tachypleus tridentatus. Relatively, the search record was very low
in TC2 (2 ind. in Sep. 2013; 1 ind. in Mar., Jun., Sep. 2014, Mar. and Jun.
2015; 4 ind. in Sep. 2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016, Mar., Jun.
and Sep. 2017).
6.5.11About the body size, larger individuals of Carcinoscorpius rotundicauda were
usually found in ST and TC1 relative to those in TC3. For Tachypleus tridentatus, larger individuals were usually found in ST
followed by TC3 and TC1. Throughout the monitoring period, it was
obvious that TC3 and ST (western shore of Tung Chung Wan) was an important
nursery ground for horseshoe crab especially newly hatched individuals due to
larger area of suitable substratum (fine sand or soft mud) and less human
disturbance (far from urban district). Relatively, other sampling zones were
not a suitable nursery ground especially TC2. Possible factors were less area
of suitable substratum (especially TC1) and higher human disturbance (TC1 and
TC2: close to urban district and easily accessible). In TC2, large daily
salinity fluctuation was a possible factor either since it was flushed by two
rivers under tidal inundation. The individuals inhabiting TC1 and TC2 were
confined in small foraging area due to limited area of suitable substrata.
Although a mating pair of Carcinoscorpius
rotundicauda was found in TC2, the hatching rate and survival rate of newly
hatched individuals were believed very low.
Seasonal
variation of horseshoe crab population
6.5.12Throughout the
monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures
3.3 and 3.4 of Appendix I). In Dec. 2012,
4 individuals of Carcinoscorpius
rotundicauda and 12 individuals of Tachypleus
tridentatus were found only. In Dec. 2013, no individual of horseshoe crab
was found. In Dec. 2014, 2 individuals of Carcinoscorpius
rotundicauda and 8 individuals of Tachypleus
tridentatus were found only. In Dec. 2015, 2 individuals of Carcinoscorpius rotundicauda, 6
individuals of Tachypleus tridentatus
and one newly hatched, unidentified individual were found only. The horseshoe
crabs were inactive and burrowed in the sediments during cold weather (<15
ºC). Similar results of low search record in dry season were reported in a
previous territory-wide survey of horseshoe crab. For example, the search
records in Tung Chung Wan were 0.17 ind. hr-1 person-1 and 0.00 ind. hr-1
person-1 in wet season and dry season respectively (details see Li, 2008).
Relatively the serach records were much higher in Dec. 2016. There were totally
70 individuals of Carcinoscorpius
rotundicauda and 24 individuals of Tachypleus
tridentatus in TC3 and ST. Because the survey was arranged in early
December while the weather was warm with sunlight (~22 ºC during dawn according
to Hong Kong Observatory database, Chek Lap Kok station on 5 Dec). In contrast,
there was no search record in TC1 and TC2 because the survey was conducted in
mid December with colder and cloudy weather (~20 ºC during dawn on 19 Dec). The
horseshoe crab activity would decrease gradually with the colder climate.
6.5.13From Sep. 2012 to
Dec. 2013, Carcinoscorpius rotundicauda
was a less common species relative to Tachypleus
tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This
species had ever been believed of very low density in ST hence the encounter
rate was very low. Since Mar. 2014, it was found in all sampling zones with
higher abundance in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and spawning of this species had
occurred about 3 years ago along the coastline of Tung Chun Wan. However, these
individuals were still small while their walking trails were inconspicuous.
Hence there was no search record in previous sampling months. Since Mar. 2014,
more individuals were recorded due to larger size and higher activity (i.e.
more conspicuous walking trail).
6.5.14For Tachypleus
tridentatus, sharp increase of number of individuals was recorded in ST
during the wet season of 2013 (from Mar. to Sep.). According to a personal
conversation with Prof. Shin (CityU), his monitoring team had recorded similar
increase of horseshoe crab population during wet season. It was believed that
the suitable ambient temperature increased its conspicuousness. However similar
pattern was not recorded in the following wet seasons. The number of
individuals increased in Mar. and Jun. 2014 followed by a rapid decline in Sep.
2014. Then the number of individuals fluctuated slightly in TC3 and ST until
Mar. 2017. Apart from natural mortality, migration from nursery soft shore to
subtidal habitat was another possible cause. Since the mean prosomal width of Tachypleus
tridentatus continued to grow and reached about 50 mm since Mar. 2014. Then
it varied slightly between 35-65 mm from Sep. 2014 to Mar. 2017. Most of the
individuals might have reached a suitable size (e.g. prosomal width 50-60 mm)
strong enough to forage in sub-tidal habitat. In Jun. 2017, the number of
individuals increased sharply again in TC3 and ST. Although mating pair of Tachypleus
tridentatus was not found in previous surveys, there should be new round of
spawning in the wet season of 2016. The individuals might have grown to a more
conspicuous size in 2017 accounting for higher search record.
6.5.15Recently, Carcinoscorpius rotundicauda was a more
common horseshoe crab species in Tung Chung Wan. It was recorded in the four
sampling zones while the majority of population located in TC3 and ST. Due to
potential breeding last year, Tachypleus
tridentatus became common again and distributed in TC3 and ST only. Since
TC3 and ST were regarded as important nursery ground for both horseshoe crab
species, box plots of prosomal width of two horseshoe crab species were
constructed to investigate the changes of population in details.
Box plot of horseshoe
crab populations in TC3
6.5.16Figure 3.6 of Appendix I shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. In Mar 2014, the major size (50% of individual records
between upper (top of red box) and lower quartile (bottom of blue box)) ranged
40-60 mm while only few individuals were found. From Mar. 2014 to Jun. 2017,
the median prosomal width (middle line of whole box) and major size (whole box)
decreased after Mar. of every year. It was due to more small individuals found.
It indicated new rounds of spawning. Also there were slight increasing trends
of body size from Jun. to Mar. of next year since 2015. It indicated a stable
growth of individuals. Focused on larger juveniles (upper whisker), the size
range was quite variable (prosomal width 60-90 mm) along the sampling months.
Juveniles reaching this size might gradually migrate to sub-tidal habitats.
6.5.17For Tachypleus
tridentatus, the major size ranged 20-50 mm while the number of individuals
fluctuated from Sep. 2012 to Jun. 2014. Then a slight but consistent growing
trend was observed from Sep. 2014 to Jun. 2015. The prosomal width increased
from 25-35 mm to 35-65 mm. As mentioned, the large individuals might have
reached a suitable size for migrating from the nursery soft shore to subtidal
habitat. It accounted for the declined population in TC3. From Mar. to Sep.
2016, slight increasing trend of major size was noticed again. From Dec. 2016
to Jun. 2017, similar increasing trend of major size was noted with much higher
number of individuals. It reflected new round of spawning. In Sep. 2017
(present survey), the major size decreased while the trend was different from
previous two years. Such decline might be the cause of serial cyclone hit
between Jun. and Sep. 2017 (to be discussed in the 'Seagrass survey' section).
Across the whole monitoring period, the larger juveniles (upper whisker)
reached 60-80 mm in prosomal width while it could reach 90 mm in present
survey. Juveniles reaching this size might gradually migrate to sub-tidal
habitats.
Box plot of horseshoe crab populations in ST
6.5.18Figure 3.7 of Appendix I shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. From Mar. 2014 to Sep. 2017, the size of major population
decreased and more small individuals (i.e. lower whisker) were recorded after
Jun. of every year. It indicated new round of spawning. Also there were similar
increasing trends of body size from Sep. to Jun. of next year between 2014 and
2017. It indicated a stable growth of individuals. Across the whole monitoring
period, the larger juveniles (i.e. upper whisker) usually ranged 60-80 mm in
prosomal width except one individual (prosomal width 107.04 mm) found in Mar.
2017. It reflected juveniles reaching this size would gradually migrate to
sub-tidal habitats.
6.5.19For Tachypleus tridentatus, a consistent
growing trend was observed for the major population from Dec. 2012 to Dec. 2014
regardless of change of search record. The prosomal width increased from 15-30
mm to 60-70 mm. As mentioned, the large juveniles might have reached a suitable
size for migrating from the nursery soft shore to subtidal habitat. From Mar.
to Sep. 2015, the size of major population decreased slightly to a prosomal
width 40-60 mm. At the same time, the number of individuals decreased
gradually. It further indicated some of large juveniles might have migrated to
sub-tidal habitat, leaving the smaller individuals on shore. There was an overall
growth trend. In Dec. 2015, two big individuals (prosomal width 89.27 mm and
98.89 mm) were recorded only while it could not represent the major population.
In Mar. 2016, the number of individual was very few in ST that no boxplot could
be produced. In Jun. 2016, the prosomal width of major population ranged 50-70
mm. But it dropped clearly to 30-40 mm in Sep. 2016 followed by an increase to
40-50 mm in Dec. 2016, 40-70 mm in Mar. 2017 and 50-60mm in Jun. 2017. Based on
overall higher number of small individuals from Jun. 2016 to Sep. 2017 (present
survey), it indicated new round of spawning. Throughout the monitoring period,
the larger juveniles ranged 60-80 mm in prosomal width. Juveniles reaching this
size would gradually migrate to sub-tidal habitats.
6.5.20As a
summary for horseshoe crab populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014
to 2016 while the spawning time should be in spring. There were consistent,
increasing trends of population size in these two sampling zones. For Tachypleus tridentatus, small
individuals were rarely found in both zones from 2014 to 2015. It was believed
no occurrence of successful spawning. The existing individuals (that recorded
since 2012) grew to a mature size and migrated to sub-tidal habitat. Hence the
number of individuals decreased gradually. In 2016, new round of spawning was
recorded in ST while increasing number of individuals and body size was
noticed.
6.5.22In the present survey, no seagrass bed was recorded
in Tung Chung Wan. Extensive area of mudflat, where used to be covered by
seagrass beds, re-exposed along TC3 and ST (Figure 3.8 of Appendix I). In the
previous survey of Jun. 2017, two species of seagrass Halophila ovalis and Zostera
japonica were recorded in TC3 and ST (Figure
3.9 of Appendix I). There was still extensive seagrass area (~17046.5 m2)
of Halophila ovalis along the mudflat
between TC3 and ST at 0.5-2.0 m above C.D.. Another seagrass species Zostera japonica, which was much lower
in vegetation area (~105.4 m2), was co-existing with few patches of Halophila ovalis nearby the mangrove
strand. The disappearance of seagrass beds would be discussed in later
paragraphs.
6.5.23According
to the previous results, majority of seagrass bed was confined in ST, the
temporal change of both seagrass species were investigated in details:
Temporal
variation of seagrass beds
6.5.24Figure 3.10 of Appendix I shows the changes of estimated total area of
seagrass beds in ST along the sampling months. For Zostera japonica, it
was not recorded in the 1st and 2nd surveys of monitoring
programme. Seasonal recruitment of few, small patches (total seagrass area: 10
m2) was found in Mar. 2013 that grew within the large patch of
seagrass Halophila ovalis. Then the patch size increased and merged
gradually with the warmer climate from Mar. to Jun. 2013 (15 m2).
However the patch size decreased and remained similar from Sep. 2013 (4 m2)
to Mar. 2014 (3 m2). In Jun. 2014, the patch size increased
obviously again (41 m2) with warmer climate followed by a decrease
between Sep. 2014 (2 m2) and Dec. 2014 (5 m2). From Mar. to
Jun. 2015, the patch size increased sharply again (90 m2). It might be due to
the disappearance of the originally dominant seagrass Halophila ovalis
resulting in less competition for substratum and nutrients. From Sep.2015 to
Jun.2016, it was found coexisting with seagrass Halophila ovalis with
steady increasing patch size (from 44 m2 to 115 m2) and
variable coverage. In Sep. 2016, the patch size decreased again to (38 m2)
followed by an increase to a horizontal strand (105.4 m2) in Jun.
2017 (present survey). And it was no longer co-existing with Halophila
ovalis. Between Sep. 2014 and Jun. 2017, an increasing trend was noticed
from Sep. to Jun. of next year followed by a rapid decline in Sep. of next
year. It was possibly the causes of heat stress, typhoon and stronger grazing
pressure during wet season. In the present survey, no seagrass patch of Zostera
japonica was found. Such disappearance matched the findings of previous
monitoring period.
6.5.25For Halophila ovalis, it was recorded as 3-4 medium to large
patches (area 18.9-251.7 m2; vegetation coverage
50-80%) beside the mangrove vegetation at tidal level 2 m above C.D. in Sep.
2012 (first survey). The total seagrass bed area grew steadily from 332.3 m2 in Sep. 2012 to 727.4 m2 in Dec. 2013. Flowers
were observed in the largest patch during its flowering period. In Mar. 2014,
31 small to medium patches were newly recorded (variable area 1-72 m2 per patch, vegetation
coverage 40-80% per patch) in lower tidal zone between 1.0 and 1.5 m above C.D.
The total seagrass area increased further to 1350 m2. In Jun. 2014, these
small and medium patches grew and extended to each other. These patches were no
longer distinguishable and were covering a significant mudflat area of ST. It
was generally grouped into 4 large patches (1116 – 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, very small patches of Halophila ovalis could be found in other
mud flat area in addition to the recorded patches. But it was hardly
distinguished due to very low coverage (10-20%) and small leaves.
6.5.26In Dec. 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.10 of Appendix I shows the
difference of the original seagrass beds area nearby the mangrove vegetation at
high tidal level between Jun. 2014 and Dec. 2014. Such rapid loss would not be
seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m
above C.D.) were present and normal in December 2012 and 2013. According to
Fong (1998), similar incident had occurred in ST in the past. The original
seagrass area had declined significantly during the commencement of the
construction and reclamation works for the international airport at Chek Lap
Kok in 1992. The seagrass almost disappeared in 1995 and recovered gradually
after the completion of reclamation works. Moreover, incident of rapid loss of
seagrass area was also recorded in another intertidal mudflat in Lai Chi Wo in
1998 with unknown reason.Hence Halophila ovalis was regarded as a
short-lived and r-strategy seagrass
that could colonize areas in short period but disappears quickly under
unfavourable conditions (Fong, 1998).
Unfavourable conditions to seagrass Halophila ovalis
6.5.27Typhoon or strong
water current was suggested as one unfavourable condition to Halophila ovalis (Fong, 1998). As
mentioned above, there were two tropical cyclone records in Hong Kong in Sep.
2014. The strong water current caused by the cyclones might have given damage
to the seagrass beds.
6.5.28Prolonged light deprivation due to turbid water
would be another unfavouable condition. Previous studies reported that Halophila
ovalis had little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999).
Hence the seagrass bed of this species was susceptible to temporary light
deprivation events such as flooding river runoff (Longstaff and Dennison,
1999).
6.5.29In order to
investigate any deterioration of water quality (e.g. more turbid) in ST, the
water quality measurement results at two closest monitoring stations SR3 and
IS5 of the EM&A programme were obtained from the water quality monitoring
team. Based on the results from June to December 2014, the overall water quality
was in normal fluctuation except there was one exceedance of suspended solids
(SS) at both stations in September. On 10th Sep., 2014, the SS
concentrations measured during mid-ebb tide at stations SR3 (27.5 mg/L) and IS5
(34.5 mg/L) exceeded the Action Level (≤23.5 mg/L and 120% of upstream control
station’s reading) and Limit Level (≤34.4 mg/L and 130% of upstream control
station’s reading) respectively. The turbidity readings at SR3 and IS5 reached
24.8-25.3 NTU and 22.3-22.5 NTU respectively. The temporary turbid water should
not be caused by the runoff from upstream rivers. Because there was no rain or
slight rain from 1st to 10th Sep. 2014 (daily total rainfall at the Hong Kong
International Airport: 0-2.1 mm; extracted from the climatological data of Hong
Kong Observatory). The effect of upstream runoff on water quality should be
neglectable in that period. Moreover the exceedance of water quality was
considered unlikely to be related to the contract works of HKLR according to
the ‘Notifications of Environmental Quality Limits Exceedances’ provided by the
respective environmental team. The respective construction of seawall and stone
column works, which possibly caused turbid water, were carried out within silt
curtain as recommended in the EIA report. Moreover there was no leakage of
turbid water, abnormity or malpractice recorded during water sampling. In
general, the exceedance of suspended solids concentration was considered to be
attributed to other external factors, rather than the contract works.
6.5.30Based on the
weather condition and water quality results in ST, the co-occurrence of cyclone
hit and turbid waters in Sep. 2014 might have combined the adverse effects on Halophila ovalis that leaded to
disappearance of this short-lived and r-strategy seagrass species. Fortunately Halophila ovalis was a fast-growing
species (Vermaat et al., 1995).
Previous studies showed that the seagrass bed could be recovered to the
original sizes in 2 months through vegetative propagation after experimental
clearance (Supanwanid, 1996). Moreover it was reported to recover rapidly in
less than 20 days after dugong herbivory (Nakaoka and Aioi, 1999). As
mentioned, the disappeared seagrass in ST in 1995 could recover gradually after
the completion of reclamation works for international airport (Fong, 1998). The
seagrass beds of Halophila ovalis
might recolonize the mudflat of ST through seed reproduction as long as there
was no unfavourable condition in the coming months.
Recolonization of seagrass beds
6.5.31Figure
3.10 of Appendix I
shows the recolonization of seagrass bed area in ST from Dec. 2014 to Jun.
2017. From Mar. to Jun. 2015, 2-3 small patches of Halophila ovalis were newly found coinhabiting with another
seagrass species Zostera japonica.
But its total patch area was still very low relative to the previous records.
The recolonization rate was low while cold weather and insufficient sunlight
were possible factors between Dec. 2014 and Mar. 2015. Moreover, it would need
to compete with seagrass Zostera japonica
for substratum and nutrient. Since Zostera
japonica had extended and had covered the original seagrass bed of Halophila ovalis at certain degree. From
Jun. 2015 to Mar. 2016, the total seagrass area of Halophila ovalis had increased rapidly from 6.8 m2 to 230.63 m2. It had recolonized its
original patch locations and covered Zostera
japonica. In Jun. 2016, the total seagrass area increased sharply to 4707.3
m2.
Similar to the previous records of Mar to Jun. 2014, the original patch area
increased further to a horizontally long strand. Another large seagrass beds
colonized the lower tidal zone (1.0-1.5 m above C.D.). In Sep. 2016, this patch
extended much and covered significant soft mud area of ST, resulting in sharp
increase of total area (24245 m2). It indicated the second
extensive colonization of this r-strategy seagrass. In Dec. 2016, this
extensive seagrass patch decreased in size and had separated into few,
undistinguishable patches. Moreover, the horizontal strand nearby the mangrove
vegetation decreased in size (Figure
3.10 of Appendix I). The total seagrass bed decreased to 12550 m2. From Mar. to Jun. 2017, the
seagrass bed area remained generally stable (12438-17046.5 m2) but the vegetation coverage
fluctuated (20-50% in Mar. 2017 to 80-100% in Jun. 2017).
Re-disappearance of seagrass bed
6.5.32In present survey, the whole seagrass bed of Halophila ovalis disappeared again along
the shore of TC3 and ST (Figure 3.10 of Appendix I).
It was similar to the case between Sep. and Dec. 2014. As mentioned, strong
water current (e.g. cyclone) or deteriorated water quality (e.g. high
turbidity) were the possible causes.
6.5.33Between the survey periods of Jun. and Sep.
2017, there were four tropical cyclone records in Hong Kong (Merbok in 12-13th,
Jun.; Roke in 23rd, Jul.; Hato in 22-23rd, Aug.; Pakhar
in 26-27th, Aug.) (online database of Hong Kong Observatory). All of
them reaches signal 8 or above especially Hato (highest signal 10).
6.5.34According to the water quality monitoring
results (Jul. to Aug. 2017) of the two closest monitoring stations SR3 and I5
of the respective EM&A programme, the overall water quality was in normal
fluctuation. There was one exceedance of suspended solids (SS) at SR3 on 12
Jul. 2017. The SS concentration reached 24.7 mg/L during mid-ebb tide. It
exceeded the Action Level (≤23.5 mg/L) but was far below the Limit Level ((≤34.4 mg/L). Since such exceedance was slight and temporary, its
effect to seagrass bed should be minimal.
6.5.35Overall, the disappearance of seagrass beds in
ST was believed the cause of serial cyclone hit in Jul and Aug. 2017. Based on
previous findings, the seagrass beds of both species were expected to
recolonize the mudflat as long as the vicinal water quality was normal. The
recolonization would be a gradual process lasting for about 1.5 years.
6.5.37Table 3.2 and Figure 3.12 of Appendix I show the types of substratum along the
horizontal transect at every tidal level in all sampling zones. The relative
distribution of different substrata was estimated by categorizing the
substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random
quadrats along the horizontal transect. The distribution of substratum types
varied among tidal levels and sampling zones:
·In TC1, high percentage of ‘Gravels and Boulders’
(70%) was recorded at high tidal level followed by ‘Sands’ (30%). Even distribution
of ‘Gravels and Boulders’ (40%) and ‘Sands’ (40%) were recorded at mid tidal
level. Relatively, the substratum types of low tidal level were different while
higher percentages of ‘Sands’ (60%) and ‘Soft mud’ (30%) were recorded.
·In TC2, the substartum types were recorded evenly
at high and mid tidal levels ('Soft mud' 40-50%, 'Gravels and Boulders' 30%,
'Sands' 20-30%,). At low tidal level, the major substratum type was 'Soft mud'
(80%) followed by 'Gravels and Boulders' (20%).
·In TC3, high percentages of ‘Sands’ (70-90%) were
recorded at high and mid tidal levels followed by ‘Soft mud’ (10-30%). At low
tidal level, the major substratum type was ‘Gravels and Boulders’ (80%).
·In ST, ‘Gravels and Boulders’ was the main
substratum (100%) at high and mid tidal levels. At low tidal level, the
substartum types were mainly ‘Soft mud’ (60%) and 'Sands' (40%).
6.5.38There
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.
6.5.39Table 3.3 of Appendix I lists the total abundance, density and
number of taxon of every phylum in this survey. A total of 12099 individuals
were recorded. Mollusca was clearly the most abundant phylum (total abundance
11160 ind., density 372 ind. m-2, relative abundance 92.2%). The
second to fourth abundant phya were Arthropoda (803 ind., 27 ind. m-2,
6.6%), Annelida (72 ind., 2 ind. m-2, 0.6%) and Sipuncula (37 ind.,
1 ind. m-2, 0.3%) respectively. Relatively other phyla were very low
in abundances (density £1 ind. m-2, relative abundance £0.2%). Moreover, the most diverse phylum was
Mollusca (37 taxa) followed by Arthropoda (14 taxa) and Annelida (6 taxa).
There was 1-2 taxa recorded only for other phyla. The taxonomic resolution and
complete list of collected specimens are shown in Annexes IV and V of Appendix I respectively.
6.5.40Table 3.4 of Appendix I shows the number of individual, relative
abundance and density of each phylum in every sampling zone. The total
abundance (1838-4026 ind.) varied among the four sampling zones while the phyla
distributions were similar. In general, Mollusca was the most dominant phylum
(no. of individuals: 1720-3638 ind.; relative abundance 89.0-95.2%; density
229-485 ind. m-2). Other phyla were much lower in number of
individuals. Arthropoda was the second abundant phylum (107-402 ind.;
3.7-10.0%; 14-54 ind. m-2). Annelida was the third abundant phylum
in TC2 and TC3 (26-33 ind.; 0.7-1.4%; 3-4 ind. m-2) and fourth
abundant in TC1 (12 ind.; 0.3%; 2 ind. m-2). Sipuncula was
relatively common in TC1 and TC3 (12-16 ind.; 0.3-0.4%; 2 ind. m-2).
Relatively other phyla were low in abundance in all sampling zones (≤ 0.2%).
Dominant species in every sampling zone
6.5.41Table
3.5 of Appendix I lists the abundant species (relative
abundance >10%) in every sampling zone. In the present survey, most of the
listed abundant species were of low to moderate densities (50-250 ind. m-2).
Few listed species of high or very high density (> 250 ind. m-2)
were regarded as dominant species. Other listed species of lower density (<
50 ind. m-2) were regared as common species.
6.5.42In TC1, the major substratum type was
‘Gravels and Boulders’ at high tidal level. There was dominant gastropod Batillaria multiformis (337 ind. m-2,
relative abundance 63%) followed by gastropods Cerithidea djadjariensis (84 ind. m-2, 16%) and Cerithidea cingulata (62 ind. m-2,
11%) at low densities. At mid tidal level (substratum types ‘Gravels and
Boulders’ and ‘Sands’), there were few abundant speices at low to moderate
densities including gastropods Cerithidea
djadjariensis (109 ind. m-2, 23%), Monodonta labio (81 ind. m-2, 17%), Batillaria multiformis (59 ind. m-2, 13%), Cerithidea cingulata (58 ind. m-2,
12%), as well as rock oyster Saccostrea
cucullata (106 ind. m-2, 22%, attached on boulders). At low
tidal level, few intertidal fauna were recorded in the major substratum type
‘Sands’. However abundant rock oyster Saccostrea
cucullata (176 ind. m-2, 29%) and barnacle Balanus amphitrite (115 ind. m-2, 19 %) were attaching
on the boulders.
6.5.43In TC2, gastropod Cerithidea djadjariensis (172 ind. m-2, 40%) was
abundant at moderate-high density at high tidal level (major substratum types:
‘Soft mud’ and 'Sands') followed by gastropod Cerithidea cingulata (89 ind. m-2, 21%) and rock oyster Saccostrea cucullata (56 ind. m-2,
13%, attached on boulders). At mid and low tidal levels (major substratum
types: ‘Soft mud’ and 'Gravels and Boulders'), gastropods Cerithidea djadjariensis (32-83 ind. m-2, 15-25%),
Batillaria zonalis (42-63 ind. m-2, 19-20%) and rock oyster Saccostrea cucullata (61-62 ind. m-2,
18-29%) were found common at low-moderate densities generally.
6.5.44In TC3, the major substratum type was ‘Sands’ at both high and mid
tidal levels. Gastropod Cerithidea djadjariensis was the dominant
species of moderate to high density (256-365 ind. m-2, 51-58%) followed by another gastropod Cerithidea cingulata
(129-163 ind. m-2, 26%). Besides gastropod Batillaria multiformis (73 ind. m-2, 12%) was relatively abundant at high tidal level. At low tidal level
(major substratum: ‘Gravels and Boulders’), rock oyster Saccostrea cucullata
(163 ind. m-2, 42%) and gastropod Monodonta labio (126 ind. m-2, 32%) were abundant at moderate densities.
6.5.45In ST,
there was no clearly abundant species at all tidal levels. Gastropod Batillaria multiformis (56 ind. m-2,
24%), Monodonta labio (46 ind. m-2,
19%) and rock oyster Saccostrea cucullata
(35 ind. m-2, 15%) were common species at high tidal level (major
substratum: ‘Gravels and Boulders’). At mid tidal level (major substratum:
‘Gravels and Boulders’), rock oyster Saccostrea
cucullata (117 ind. m-2, 33%) was abundant at moderate density
followed by low-density gastropods Monodonta
labio (63 ind. m-2, 18 %), Lunella
coronata (46 ind. m-2, 13%) and Cerithidea djadjariensis (41 ind. m-2, 12%). At low
tidal level (major substratum types: ‘Sands’ and ‘Soft mud’), there were common
taxa only including rock oyster Saccostrea
cucullata (28 ind. m-2, 20%, attached on boulders), barnacle Balanus amphitrite (25 ind. m-2,
18%, attached on boulders), gastropods Cerithidea
djadjariensis (24 ind. m-2, 17%) and Batillaria zonalis (14 ind.
m-2, 10%).
6.5.46In
general, there was no consistent zonation pattern of species distribution
across all sampling zones and tidal levels. The species distribution should be
determined by the type of substratum primarily. In general, gastropods Cerithidea djadjariensis (total number
of individuals: 2993 ind., relative abundance 24.7%), Cerithidea cingulata (1548 ind., 12.8%), Batillaria multiformis (1443 ind., 11.9%) and Batillaria zonalis
(509 ind., 4.2%) were the most commonly occurring species on sandy and soft mud
substrata. Rock oyster Saccostrea
cucullata (2101 ind., 17.4%), gastropods Monodonta labio (1116 ind., 9.2%), Lunella coronata (323 ind., 2.7%), barnacle Balanus amphitrite (438 ind., 3.6%) were commonly occurring species
inhabiting gravel and boulders substratum.
Biodiversity and abundance of soft shore
communities
6.5.47Table 3.7 of Appendix I shows the mean
values of species number, density, biodiversity index H’ and species evenness J
of soft shore communities at every tidal level and in every sampling zone. As
mentioned above, the differences among sampling zones and tidal levels were
determined by the major type of substratum primarily.
6.5.48Among the sampling
zones, there was no obvious difference of mean species number, H' and J across all tidal levels. The mean species numbers of TC1, TC2 and
ST (9-10 spp. 0.25 m-2) were slightly higher than TC3 (7 spp. 0.25 m-2).
The mean densities of TC1 and TC3 (509-537 ind. m-2) were higher
than TC2 and ST (245-322 ind. m-2). Since TC3 was higher in mean
density and was highly dominant by few species, the mean H’ (1.1) was relatively lower than other three sampling zones
(1.4-1.6). Overall the mean J was
similar among the four sampling zones (0.6-0.8).
6.5.49Across the tidal
levels, there was no consistent difference of the mean species number, H' and J in all sampling zones. For the mean density, there were generally
decreasing trends in TC2, TC3 and ST from high to low tidal level.
6.5.50Figures 3.13 to 3.16 of Appendix I show the temporal changes of mean species number,
mean density, H’ and J at every tidal level and in every
sampling zone along the sampling months. In general, all the biological
parameters fluctuated seasonally throughout the monitoring period. Lower mean
species number and density were recorded in dry season (Dec.) but the mean H' and J fluctuated within a stable range.
6.5.51Focusing on the
changes of mean density in ST, there were steady decreasing trends regardless
of tidal levels since the beginning of monitoring period. It might be an
unfavourable change that reflected environmental stresses. The mean densities
increased again from Dec. 2016 to Jun. 2017 reflecting a recovery process. But
it decreased again in Sep. 2017 (present survey) while the heat stress and
serial cyclone hit of this wet season were believed the causes. Because similar
decreases of density were noted in other sampling zones either.
6.6.1Chan, K.K., Caley, K.J., 2003. Sandy Shores, Hong
Kong Field Guides 4. The Department of Ecology & Biodiversity, The
University of Hong Kong. pp 117.
6.6.2Dai, A.Y., Yang, S.L., 1991. Crabs of the China
Seas. China Ocean Press. Beijing.
6.6.3Dong, Y.M., 1991. Fauna of ZheJiang Crustacea.
Zhejiang Science and Technology Publishing House. ZheJiang.
6.6.4EPD, 1997. Technical Memorandum on Environmental
Impact Assessment Process (1st edition). Environmental Protection Department,
HKSAR Government.
6.6.5Fauchald, K., 1977. The polychaete worms.
Definitions and keys to the orders, families and genera. Natural History Museum
of Los Angeles County, Science Series 28. Los Angeles, U.S.A..
6.6.6Fong, C.W., 1998. Distribution of Hong Kong
seagrasses. In: Porcupine! No. 18. The School of Biological Sciences, The
University of Hong Kong, in collaboration with Kadoorie Farm & Botanic
Garden Fauna Conservation Department, p10-12.
6.6.7Li, H.Y., 2008. The Conservation of Horseshoe Crabs
in Hong Kong. MPhil Thesis, City University of Hong Kong, pp 277.
6.6.8Longstaff, B.J., Dennison, W.C., 1999. Seagrass
survival during pulsed turbidity events: the effects of light deprivation on
the seagrasses Halodule pinifolia and Halophila
ovalis. Aquatic Botany 65 (1-4), 105-121.
6.6.9Longstaff, B.J., Loneragan, N.R., O’Donohue, M.J.,
Dennison, W.C., 1999. Effects of light deprivation on the survival and recovery
of the seagrass Halophila ovalis (R.
Br.) Hook. Journal of Experimental Marine Biology and Ecology 234 (1), 1-27.
6.6.10Nakaoka, M., Aioi, K., 1999. Growth of seagrass Halophila ovalis at dugong trails
compared to existing within-patch variation in a Thailand intertidal flat.
Marine Ecology Progress Series 184, 97-103.
6.6.11Pielou, E.C., 1966. Shannon’s formula as a measure
of species diversity: its use and misuse. American Naturalist 100, 463-465.
6.6.12Qi, Z.Y., 2004. Seashells of China. China Ocean
Press. Beijing, China.
6.6.13Qin, H., Chiu, H., Morton, B., 1998. Nursery
beaches for Horseshoe Crabs in Hong Kong. In: Porcupine! No. 18. The School of
Biological Sciences, The University of Hong Kong, in collaboration with
Kadoorie Farm & Botanic Garden Fauna Conservation Department, p9-10.
6.6.14Shannon, C.E., Weaver, W., 1963. The Mathematical
Theory of Communication. Urbana: University of Illinois Press, USA.
6.6.15Shin, P.K.S., Li, H.Y., Cheung, S.G., 2009.
Horseshoe Crabs in Hong Kong: Current Population Status and Human Exploitation.
Biology and Conservation of Horseshoe Crabs (part 2), 347-360.
6.6.16Supanwanid, C., 1996. Recovery of the seagrass Halophila ovalis after grazing by
dugong. In: Kuo, J., Philips, R.C., Walker, D.I., Kirkman, H. (eds), Seagrass
biology: Proc Int workshop, Rottenest Island, Western Australia. Faculty of
Science, The University of Western Australia, Nedlands, 315-318.
6.6.17Vermaat, J.E., Agawin, N.S.R., Duarte, C.M.,
Fortes, M.D., Marba. N., Uri, J.S., 1995. Meadow maintenance, growth and
productivity of a mixed Philippine seagrass bed. Marine Ecology Progress Series
124, 215-225.
6.6.18Yang, D.J, Sun, R.P., 1988. Polychaetous annelids
commonly seen from the Chinese waters (Chinese version). China Agriculture
Press, China.
7.1.1Site
Inspections were carried out on a weekly basis to monitor the implementation of
proper environmental pollution control and mitigation measures for the Project.
During the reporting month, four site inspections were carried out on 6, 13, 20
and 29 September 2017.
7.1.2A summary
of observations found during the site inspections and the follow up actions
taken by the Contractor are described in Table 7.1.
Table 7.1Summary
of Environmental Site Inspections
Date of Audit
Observations
Actions Taken
by Contractor / Recommendation
Date of
Observations Closed
29 Aug 2017
1. Waste was
observed at Ventilation Building.
2. More than 20
bags of cement were not properly covered at Ventilation Building.
3. Chemical container
was observed without drip tray at Ventilation Building.
4.
Waste was observed at N1.
1.The waste was removed
from Ventilation Building.
2.The cement bags were
covered properly at Ventilation Building.
3.The chemical container
was removed from Ventilation Building.
4.The waste was removed
from N1.
6 Sep 2017
6 Sep 2017
1. A skip was overloaded with waste at Depress
Roundabout.
2. Stagnant water was observed at N4.
3. Waste was observed at N4.
4. Concrete waste was observed at S15.
5. Waste was observed at S16.
6.
Dust emission from vehicle movement was observed
at S25.
1.The waste was removed from the skip at Depress Roundabout.
2.The stagnant water was removed from N4.
3.The waste was removed from N4.
4.The concrete waste was removed from S15.
5.The waste was removed from S16.
6.Water spraying for dust suppression was provided for the access road
at S25.
13 Sep 2017
13 Sep 2017
1. Stagnant water was observed at N4.
2. Broken water barriers were not covered
properly at S7.
3. Water seepage was observed at S7.
4. Waste was accumulated at S9.
5. Stagnant
water was observed at N4.
6. Waste was
accumulated at N4.
7. Sandbag
barriers were not maintained properly at S25.
1. The stagnant water was removed from N4.
2. The broken water barriers were fixed at S7.
3. The water seepage was prevented by deployment of
sandbag barriers at S7.
4. The waste was removed from S9.
5. The stagnant water was removed from N4.
6. The waste was removed from N4.
7. The broken
sandbag barriers were replaced and their gaps were closed at S25.
20 Sep 2017
20 Sep 2017
1. Gaps of silt
curtain were observed at Portion X.
2. Waste was
accumulated at Depress Roundabout.
3. Oil drums were
observed without drip tray at Depress Roundabout.
4. A skip was
overloaded with waste at Depress Roundabout.
5. Waste was
accumulated at HMA.
6. Poor
housekeeping was observed at HMA.
7. Stagnant water
was observed at HMA.
8. Waste batteries
were not stored properly at N4.
9. An oil drum
without drip tray and contaminated soil was observed at S16.
10. A dump truck was
observed without mechanical cover at S15.
1. The gaps of silt curtain were closed at
Portion X.
2. The waste was removed from Depress
Roundabout.
3. The oil drums were removed from Depress
Roundabout.
4. The waste was removed from the skip at
Depress Roundabout.
5. The waste was removed from HMA.
6. Good housekeeping was maintained at HMA.
7. Larvicide was applied to avoid mosquito
breeding at HMA.
8. The waste batteries were placed in the chemical waste storage area for
collection by licensed collector at N4.
9. The oil drum was removed from S16. The
contaminated soil was placed in the chemical
waste area storage for collection by licensed collector at S16.
10. The dump truck was covered properly at
S15.
29 Sep 2017
29 Sep 2017
1. Silt curtain with gap was observed at
Portion X.
2. Drip tray was not provided for oil drums
at A1 Bridge.
3. Chemical container was not stored in the
designated storage area at A1 Bridge.
4. NRMM label was not provided on the air
compressor at A1 Bridge.
5. Stagnant water was observed at A1
Bridge.
6. Exit of N20 was found dry and unpaved.
Muddy tracks was observed on the road outside the works area.
The Contractor was
recommended to:
1. Maintain the silt curtain properly at
Portion X.
2. Provide drip tray for the oil drums or
remove them immediately from A1 Bridge.
3. Store the chemical container in the designated
storage area at A1 Bridge.
4. Adhere a NRMM label on to the air
compressor at A1 Bridge.
5. Remove the stagnant water at A1 Bridge.
6. Water/clean the site access regularly
and provide washing facilities for cleaning the vehicles before leaving the
work area at N20.
Follow-up
actions for the observations issued for the last weekly site inspection of
the reporting month will be inspected during the next site inspections
7.1.3The
Contractor has rectified most of the observations as identified during environmental
site inspections within the reporting month. Follow-up actions for outstanding
observations will be inspected during the next site inspections.
7.2Advice on the Solid and Liquid Waste
Management Status
7.2.1The
Contractor registered as a chemical waste producer for the Project. Sufficient
numbers of receptacles were available for general refuse collection and
sorting.
7.2.2Monthly
summary of waste flow table is detailed in Appendix J.
7.2.3The
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 Practice on the Packaging, Labelling and
Storage of Chemical Wastes.
7.3.1The valid environmental licenses and permits
during the reporting month are summarized in Appendix L.
7.4Implementation
Status of Environmental Mitigation Measures
7.4.1In
response to the site audit findings, the Contractors have rectified most of theobservations as
identified during environmental site inspections during the reporting month.
Follow-up actions for outstanding observations will be inspected during the
next site inspections.
7.4.2A summary
of the Implementation Schedule of Environmental Mitigation Measures (EMIS) is
presented in Appendix M. Most of
the necessary mitigation measures were implemented properly.
7.4.3Regular
marine travel route for marine vessels were implemented properly in accordance
to the submitted plan and relevant records were kept properly.
7.4.4Dolphin
Watching Plan was implemented during the reporting month. No dolphins inside
the silt curtain were observed. The relevant records were kept properly.
7.5.1No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6
during the reporting month
7.5.2For
construction noise, no Action and Limit Level exceedances were recorded at the
monitoring station during the reporting month.
7.5.3For marine water quality monitoring, no Action
Level and Limit Level exceedances of dissolved oxygen and turbidity level were
recorded during the reporting month. There were one Action Level and one Limit
Level exceedances of suspended solids level were recorded during the reporting
month.
7.6Summary of Complaints, Notification of
Summons and Successful Prosecution
7.6.1There
was one complaint received in relation to the environmental impacts during the
reporting month. The summary of environmental complaint is presented in Table 7.2. The details of cumulative
statistics of Environmental Complaints are provided in
Appendix K.
Table 7.2A
Summary of Environmental Complaint for the Reporting Month
Environmental
Complaint No.
Date of Complaint
Received
Description of
Environmental Complaint
COM-2017-102
1823
Integrated Call Centre received
a complaint lodged by a member of the public on 30 September 2017. ET received complaint
details on 3 October 2017
Cleanliness problem at Tung Fai Road
7.6.2For
Environmental Complaint No. COM-2017-102, complaint investigation is being
undertaken and will be reported in next reporting month.
7.6.3No
notification of summons and prosecution was received during the reporting
period. Statistics on notifications of summons andsuccessful prosecutions are summarized inAppendix N.
9.1.1The
construction phase and EM&A programme of the Contract commenced on 17
October 2012. This
is the sixtieth Monthly EM&A report for the Contract which summarizes the
monitoring results and audit findings of the EM&A programme during the
reporting period from 1 to 30 September 2017.
Air Quality
9.1.2No Action and Limit Level exceedances of 1-hr TSP and 24-hr TSP were
recorded at AMS5 and AMS6 during the reporting month.
Noise
9.1.3For
construction noise, no Action and Limit Level exceedances were recorded at the
monitoring station during the reporting month.
Water Quality
9.1.4For marine water quality monitoring, no Action
Level and Limit Level exceedances of dissolved oxygen and turbidity level were
recorded during the reporting month. There were one Action Level and one Limit
Level exceedances of suspended solids level were recorded during the reporting
month.
Dolphin
9.1.5During the September’s
surveys of the Chinese White Dolphin, no adverse impact from the activities of this construction project on Chinese White Dolphins was noticeable from
general observations.
9.1.6Due to
monthly variation in dolphin occurrence within the study area, it would be more
appropriate to draw conclusion on whether any impacts on dolphins have been
detected related to the construction activities of this project in the
quarterly EM&A report, where comparison on distribution, group size and
encounter rates of dolphins between the quarterly impact monitoring period
(September 2017 – December 2017) and baseline monitoring period
(3-month period) will be made.
Mudflat
9.1.7This measurement result was generally and
relatively higher than the baseline measurement at S1, S2, S3 and S4. The
mudflat level is continuously increased.
9.1.8The
September 2017 survey results indicate that the impacts of the HKLR
project could not be detected on horseshoe crabs and intertidal soft shore
community.The disappearance
of seagrass beds was believed the cause of serial cyclone hits rather than
impact of HKLR project. Based on previous findings, the seagrass beds were
expected to recolonize the mudflat gradually in the future, as long as the
vicinal water quality remained normal.
Environmental Site Inspection
and Audit
9.1.9Environmental
site inspections were carried out on 6, 13, 20 and 29 September 2017.
Recommendations on remedial actions were given to the Contractors for the
deficiencies identified during the site inspections.
9.1.10There was one complaint (Environmental Complaint
No. COM-2017-102) received in relation to the environmental impact during the
reporting period. Complaint
investigation is being undertaken and will be reported in next reporting month.
9.1.11No
notification of summons and prosecution was received during the reporting
period.