Executive
Summary
The Hong Kong-Zhuhai-Macao
Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge
at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB
Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern
waters of the Hong Kong International Airport (HKIA).
The HKLR project has been
separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and
Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract)
and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department as the
Contractor to undertake the construction works of Contract No. HY/2011/03. The main works of the Contract include land
tunnel at Scenic Hill, tunnel underneath Airport Road and Airport Express Line,
reclamation and tunnel to the east coast of the Airport Island, at-grade road
connecting to the HKBCF and highway works of the HKBCF within the Airport
Island and in the vicinity of the HKLR reclamation. The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be ˇ§Designated Projectsˇ¨,
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.
BMT Hong Kong Limited has
been appointed by the Contractor to implement the Environmental Monitoring
& Audit (EM&A) programme for the Contract in accordance with the
Updated EM&A Manual for HKLR (Version 1.0) and will be providing
environmental team services to the Contract.
This is the seventy-third 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 31 October 2018.
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
|
2,
5, 11, 16, 22 and 26 October 2018
|
24-hr TSP Monitoring
|
4,
10, 15, 19, 25 and 31 October 2018
|
Noise Monitoring
|
2,
11, 18 and 22 October 2018
|
Water Quality Monitoring
|
1,
3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26, 29 and 31 October 2018
|
Chinese White Dolphin
Monitoring
|
4,
11, 16 and 18 October 2018
|
Mudflat Monitoring (Ecology)
|
20,
23 September 2018 and 6, 7, 20, 21 October
2018
|
Site Inspection
|
3,
10, 16, and 26 October 2018
|
Due to bad weather
condition, the noise monitoring was rescheduled from 16 October 2018 to 18
October 2018.
Due to boat unavailability, the dolphin
monitoring was rescheduled from 23 October 2018 to 18 October 2018.
Thunderstorm
Warning was issued by the Hong Kong Observatory on 6, 7, 8 September 2018. The
mudflat monitoring on 6, 7, 8 September 2018 was cancelled due to safety
reason. The mudflat monitoring was rescheduled to 20, 23 September 2018 and 6, 7, 20, 21 October 2018.
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
|
3
|
0
|
24-hr TSP
|
0
|
0
|
Noise
|
Leq (30 min)
|
0
|
0
|
Water Quality
|
Suspended solids level (SS)
|
1
|
0
|
Turbidity level
|
0
|
0
|
Dissolved oxygen level (DO)
|
0
|
0
|
Complaint Log
There was no complaint
received in relation to the environmental impacts during this 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 teamˇ¦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 Augustˇ¦s dolphin monitoring.
A new water quality monitoring team has been employed for carrying out
water quality monitoring work for the Contract starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong
International Airport into a Three-Runway System (3RS Project), original
locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed
by works boundary of 3RS Project. Alternative impact water quality monitoring
stations, naming as CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and
were adopted starting from 23 August 2017 to replace the original locations of
water quality monitoring for the Contract.
The role and responsibilities as the ET Leader of the Contract was temporarily
taken up by Mr Willie Wong instead of Ms Claudine Lee from 25 September 2017 to
31 December 2017.
Water quality monitoring
station SR10A(N) (Coordinate: 823644E, 823484N) was unreachable on 4 October
2017 during flood tide as fishing activities were observed. As such, the water
monitoring at station SR10A(N) was conducted at Coordinate: 823484E, 823593N
during flood tide on 4 October 2017 temporarily.
The topographical condition of the water monitoring
stations SR3 (Coordinate: 810525E, 816456N), SR4 (Coordinate: 814760E, 817867N),
SR10A (Coordinate: 823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot
be accessed safely for undertaking water quality monitoring. The water quality
monitoring has been temporarily conducted at alternative stations, namely
SR3(N) (Coordinate 810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and
SR10A(N) (Coordinate: 823644E, 823484N) since 1 September 2017. The water
quality monitoring at station SR10B was temporarily conducted at Coordinate:
823683E, 823187N on 1, 4, 6, 8 September 2017 and has been temporarily
fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E, 823159N)
since 11 September 2017. Proposal for permanently relocating the aforementioned
stations was approved by EPD on 8 January 2018.
According to latest
information received in July 2018, the works area WA7 was handed over to other
party on 28 February 2018 instead of 31 January 2018.
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:
ˇP
Dismantling/ trimming of Temporary 40mm Stone Platform for Construction
of Seawall at Portion X;
ˇP
Construction of Seawall at
Portion X;
ˇP
Loading and Unloading
Filling Materials at Portion X;
ˇP
Backfilling at Scenic Hill
Tunnel (Cut & Cover Tunnel) at Portion X;
ˇP
Works for Diversion of
Airport Road;
ˇP
Establishment of Site
Access at Airport Road / Airport Express Line/ East Coast Road;
ˇP
E&M/ Backfilling works for
HKBCF to Airport Tunnel West (Cut & Cover Tunnel) at Airport Road;
ˇP
E&M/ Backfilling works for
HKBCF to Airport Tunnel East (Cut & Cover Tunnel) at Portion X;
ˇP
Finishing Works for
Highway Operation and Maintenance Area Building at Portion X; and
ˇP
Finishing Works for
Scenic Hill Tunnel West Portal Ventilation building at West Portal.
1.1.2 The HKLR project has been
separated into two contracts. They
are Contract
No. HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section
between Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter
referred to as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao
Bridge Hong Kong Link Road-Section between HKSAR Boundary and Scenic Hill.
1.1.3 China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department (HyD) as the Contractor to undertake
the construction works of Contract No. HY/2011/03. The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be ˇ§Designated Projectsˇ¨,
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. The works area WA7 was
handed over to other party on 28 February 2018. Figure 1.1 shows the project site boundary. The works areas are shown in Appendix O.
1.1.4 The Contract includes the following key aspects:
ˇP
New reclamation along
the east coast of the approximately 23 hectares.
ˇP
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.
ˇP
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.
ˇP
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.
ˇP
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.
ˇP
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.
ˇP
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.
1.1.5 This is the seventy-third 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 31 October 2018.
1.1.6 BMT Hong Kong Limited has been
appointed by the Contractor to implement the EM&A programme for the
Contract in accordance with the Updated EM&A Manual for HKLR (Version 1.0) for
HKLR and will be providing environmental team services to the Contract. Ramboll
Hong
Kong Limited was employed by HyD as the Independent
Environmental Checker (IEC) and Environmental Project Office (ENPO) for the
Project. The project organization with regard to the
environmental works is as follows.
1.2.1
The 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.
Table 1.1 Contact
Information of Key Personnel
Party
|
Position
|
Name
|
Telephone
|
Fax
|
Supervising
Officerˇ¦s Representative
(Ove Arup & Partners Hong Kong Limited)
|
(Chief Resident Engineer, CRE)
|
Robert Antony Evans
|
3968 0801
|
2109 1882
|
Environmental Project Office / Independent Environmental Checker
(Ramboll 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 Hong Kong Limited)
|
Environmental Team Leader
|
Claudine Lee
|
2241 9847
|
2815 3377
|
24 hours complaint
hotline
|
---
|
---
|
5699 5730
|
---
|
|
1.3
Construction Programme
1.3.1
A copy of the
Contractorˇ¦s construction programme is provided in Appendix B.
1.4
Construction Works Undertaken During the
Reporting Month
1.4.1 A summary of the construction activities undertaken
during this reporting month is shown in
Table 1.2.
Table 1.2 Construction
Activities During Reporting Month
Description of Activities
|
Site Area
|
Dismantling/trimming
of temporary 40mm stone platform for construction of seawall
|
Portion X
|
Construction
of seawall
|
Portion X
|
Loading
and unloading of filling materials
|
Portion X
|
Backfilling
at Scenic Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Works for diversion
|
Airport Road
|
Establishment of site access
|
Airport Road/ Airport
Express Line/ East Coast Road
|
E&M/ Backfilling/ Bitumen works for HKBCF
to Airport Tunnel West (Cut & Cover Tunnel)
|
Airport Road
|
E&M/ Backfilling/ Bitumen works for HKBCF
to Airport Tunnel East (Cut & Cover Tunnel)
|
Portion X
|
Finishing
works for Highway Operation and Maintenance Area Building
|
Portion X
|
Finishing
works for Scenic Hill Tunnel West Portal Ventilation building
|
West Portal
|
2.1
Monitoring
Requirements
2.1.1 In 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.
Table 2.1 Action
and Limit Levels for 1-hour TSP
Monitoring Station
|
Action Level, µg/m3
|
Limit Level, µg/m3
|
AMS 5 ˇV Ma Wan Chung Village (Tung Chung)
|
352
|
500
|
AMS 6 ˇV Dragonair / CNAC (Group) Building (HKIA)
|
360
|
Table 2.2 Action and
Limit Levels for 24-hour TSP
Monitoring Station
|
Action Level, µg/m3
|
Limit Level, µg/m3
|
AMS 5 ˇV Ma Wan Chung Village (Tung Chung)
|
164
|
260
|
AMS 6 ˇV Dragonair / CNAC (Group) Building (HKIA)
|
173
|
260
|
2.2.1 24-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 2.3 Air
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)
|
2.3.1 Monitoring locations
AMS5 and AMS6 were set up at the proposed locations in accordance
with Contract Specific EM&A Manual.
2.3.2
Figure 2.1 shows the locations
of monitoring stations. Table 2.4
describes the details of the monitoring stations.
Table 2.4 Locations
of Impact Air Quality Monitoring Stations
Monitoring
Station
|
Location
|
AMS5
|
Ma Wan Chung Village (Tung Chung)
|
AMS6
|
Dragonair / CNAC (Group) Building (HKIA)
|
2.4.1 Table 2.5
summarizes the monitoring parameters, frequency and duration of impact TSP
monitoring.
Table 2.5 Air
Quality Monitoring Parameters, Frequency and Duration
Parameter
|
Frequency
and Duration
|
1-hour TSP
|
Three times every 6 days while the highest dust impact was expected
|
24-hour TSP
|
Once every 6 days
|
2.5.1
24-hour TSP Monitoring
(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 ˇÓ2.5% 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 ˘XC and not variable by more than ˇÓ3 ˘XC; the relative humidity (RH) was
< 50% and not variable by more than ˇÓ5%. 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.
2.5.2 1-hour TSP
Monitoring
(a) Measuring Procedures
The measuring procedures of
the 1-hour dust meter were in accordance with the Manufacturerˇ¦s Instruction
Manual as follows:-
(i)
Turn the power on.
(ii)
Close the air collecting opening cover.
(iii)
Push the ˇ§TIME SETTINGˇ¨ switch to [BG].
(iv)
Push ˇ§START/STOPˇ¨ 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 ˇ§SPAN CHECKˇ¨ is indicated in the
display.
(vii)
Push ˇ§START/STOPˇ¨ 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 ˇ§TIME SETTINGˇ¨ switch the time set in the display to 3 hours.
(x)
Lower down the air collection opening cover.
(xi)
Push ˇ§START/STOPˇ¨ 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.
2.6.1
The schedule for air quality monitoring in October 2018
is provided in Appendix D.
2.7.1
The monitoring results for
1-hour TSP and 24-hour TSP are summarized in Tables 2.6 and 2.7 respectively.
Detailed impact air quality monitoring results and relevant graphical plots are
presented in Appendix E.
Table 2.6 Summary
of 1-hour TSP Monitoring Results During the Reporting Month
Monitoring Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
AMS5
|
116
|
45 ˇV 370
|
352
|
500
|
AMS6
|
83
|
48 ˇV 193
|
360
|
500
|
Table 2.7 Summary of 24-hour TSP Monitoring Results During the
Reporting Month
Monitoring Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
AMS5
|
66
|
45 ˇV 92
|
164
|
260
|
AMS6
|
71
|
44 ˇV 102
|
173
|
260
|
2.7.2 Three Action Level exceedances of 1-hr TSP were recorded at AMS5 during the
reporting month. No Limit Level exceedance of 24-hrTSP were recorded at AMS5
during the reporting month. No Action and Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at
AMS6 during the reporting month. Records of
ˇ§Notification of Environmental Quality Limit Exceedancesˇ¨ are provided in Appendix N.
2.7.3 The event action plan
is annexed in Appendix F.
2.7.4
The
wind data obtained from the on-site weather station
during the reporting month is
shown in Appendix G.
3.1.1 In 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 3.1 Action
and Limit Levels for Noise during Construction Period
Monitoring Station
|
Time Period
|
Action Level
|
Limit Level
|
NMS5 ˇV 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)
|
3.2.1 Noise 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
|
3.3.1
Monitoring location NMS5 was set up at the
proposed locations in accordance with Contract Specific EM&A Manual.
3.3.2
Figure 2.1 shows the locations
of monitoring stations. Table 3.3 describes the details of the monitoring
stations.
Table 3.3 Locations
of Impact Noise Monitoring Stations
Monitoring Station
|
Location
|
NMS5
|
Ma Wan Chung Village (Ma
Wan Chung Resident Association) (Tung Chung)
|
3.4.1
Table 3.4 summarizes the
monitoring parameters, frequency and duration of impact noise monitoring.
Table 3.4 Noise
Monitoring Parameters, Frequency and Duration
Parameter
|
Frequency and Duration
|
30-mins measurement at
each monitoring station between 0700 and 1900 on normal weekdays (Monday to
Saturday). Leq, L10 and L90 would be
recorded.
|
At least once per week
|
3.5.1
Monitoring Procedure
(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
ˇV 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.
3.5.2
Maintenance 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.
3.6.1 The schedule for construction
noise monitoring in October 2018 is provided in Appendix D.
3.7.1 The monitoring
results for construction noise are summarized in Table 3.5 and the monitoring results and relevant graphical plots
are provided in Appendix E.
Table 3.5 Summary
of Construction Noise Monitoring Results During the Reporting Month
Monitoring Station
|
Average Leq (30 mins), dB(A)
|
Range of Leq (30 mins), dB(A)
|
Limit Level Leq (30 mins), dB(A)
|
NMS5
|
59
|
58 ˇV 61
|
75
|
3.7.2 There were no Action and Limit
Level exceedances for noise during daytime on normal weekdays of the reporting month.
3.7.3
The event action plan is annexed in Appendix F.
4
Water Quality Monitoring
4.1.1
Impact 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 ETˇ¦s
proposal on 25 March 2013. Therefore,
Action Level and Limit Level for the Contract have been changed since 25 March
2013.
4.1.2
The original and revised Action Level and
Limit Level for turbidity and suspended solid are shown in Table 4.1.
Table 4.1 Action
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
stationˇ¦s turbidity at the same tide of the same day;
The action level has been
amended to ˇ§27.5 and 120% of upstream control stationˇ¦s turbidity at the same
tide of the same dayˇ¨ 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 ˇ§47.0 and 130% of turbidity at the upstream control station at the
same tide of same dayˇ¨ since 25 March 2013.
|
Suspended Solid (SS)
(mg/L)
|
Depth average
|
23.5 or 120% of upstream control
stationˇ¦s SS at the same tide of the same day;
The action level has been
amended to ˇ§23.5 and 120% of upstream control stationˇ¦s SS at the same tide of
the same dayˇ¨ 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 ˇ§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 Intakesˇ¨ 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.
4.2.1 Table 4.2 summarizes the
equipment used in the impact water quality monitoring programme.
Table 4.2 Water
Quality Monitoring Equipment
Equipment
|
Brand and Model
|
DO and Temperature Meter,
Salinity Meter, Turbidimeter and pH Meter
|
YSI Model 6820
|
Positioning Equipment
|
JRC DGPS 224 Model
JLR-4341 with J-NAV 500 Model NWZ4551
|
Water Depth Detector
|
Eagle Cuda-168 and
Lowrance x-4
|
Water Sampler
|
Kahlsio Water Sampler
(Vertical) 2.2 L with messenger
|
4.3.1 Table 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 4.3 Impact
Water Quality Monitoring Parameters and Frequency
Monitoring Stations
|
Parameter, unit
|
Frequency
|
No. of depth
|
Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9 & IS10,
Control/Far Field
Stations:
CS2 & CS(Mf)5,
Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A & SR10B
|
ˇP
Depth, m
ˇP
Temperature, oC
ˇP
Salinity, ppt
ˇP
Dissolved Oxygen
(DO), mg/L
ˇP
DO Saturation, %
ˇP
Turbidity, NTU
ˇP
pH
ˇP Suspended Solids (SS), mg/L
|
Three times per week
during mid-ebb and mid-flood tides (within ˇÓ 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).
|
4.4.1
In 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.
4.4.2
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.
4.4.3
The topographical condition of the water monitoring stations SR3 (Coordinate:
810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A (Coordinate:
823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot be accessed
safely for undertaking water quality monitoring. The water quality monitoring has
been temporarily conducted at alternative stations, namely SR3(N) (Coordinate
810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and SR10A(N)
(Coordinate: 823644E, 823484N) since 1 September 2017. The water quality
monitoring at station SR10B was temporarily conducted at Coordinate: 823683E,
823187N on 1, 4, 6, 8 September 2017 and has been temporarily fine-tuned to
alternative station SR10B(N2) (Coordinate: 823689E, 823159N) since 11 September
2017. Proposal for permanently relocating the aforementioned stations was
approved by EPD on 8 January 2018.
4.4.4
The 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(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
|
Remark:
1) Metal beam across Tai
Ho Inlet blocked the access of station SR4(N) in all water monitoring date of
October 2018. As such, the water quality monitoring at station SR4(N) was
temporarily conducted at a location which is close to the original coordinates
of station SR4(N) (coordinates: 817859N, 814705E) as far as practicable in October 2018.
|
4.5
Monitoring
Methodology
4.5.1 Instrumentation
(a) The
in-situ water quality parameters including dissolved oxygen, temperature,
salinity and turbidity, pH were measured by multi-parameter meters.
4.5.2 Operating/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 4.5 Laboratory 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.
4.5.3 Maintenance 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.
4.6.1
The schedule for impact water quality monitoring in October 2018 is provided in Appendix D.
4.7.1 Impact 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 in Appendix E.
4.7.2
Water 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.
4.7.3 For marine water quality monitoring, no
Action Level and Limit Level exceedances of dissolved oxygen level and
turbidity level were recorded during the reporting month.
4.7.4 During the reporting month, an
Action Level exceedance of suspended solids level was recorded. No Limit Level
exceedances of suspended solids level were recorded.
4.7.5 Number of exceedances recorded
during the reporting month at each impact station are summarized in Table 4.6.
Table 4.6 Summary 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
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS7
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS8
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS(Mf)9
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS10(N)
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
10-11-2018
|
0
|
1
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
SR3(N)
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
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
|
0
|
0**
|
Notes:
S: Surface;
M: Mid-depth;
** The
total number of
exceedances
4.7.6
The exceedance suspended solid
level recorded during reporting period was 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
ˇ§Notification of Environmental Quality Limit Exceedancesˇ¨ are provided in Appendix N.
4.7.7 The event action plan is annexed
in Appendix F.
5.1.1
Impact dolphin monitoring is required to be conducted by a qualified dolphin specialist team to
evaluate whether there have
been any effects on the
dolphins.
5.1.2
The Action Level and Limit Level for dolphin monitoring are shown in Table 5.1.
Table
5.1 Action
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.
5.1.3 The 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.
Vessel-based Line-transect Survey
5.2.1
According 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 5.2 Co-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.
5.2.2
The 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 20
years of marine mammal monitoring surveys in Hong Kong developed by HKCRP (see
Hung 2017). 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.
5.2.3
Two 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.
5.2.4
During 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).
5.2.5
Data including time, position and vessel speed were
also automatically and continuously logged by handheld GPS throughout the
entire survey for subsequent review.
5.2.6
When 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.
5.2.7
Survey 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
ˇ§primaryˇ¨ survey effort, while the survey effort conducted along the connecting
lines between parallel lines was labeled as ˇ§secondaryˇ¨ 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.
5.2.8
Encounter 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
5.2.9
When 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.
5.2.10
A professional digital camera (Canon EOS 7D 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.
5.2.11
All 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.
5.2.12
Chinese 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).
5.2.13 All
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.
Vessel-based Line-transect Survey
5.3.1
During the month of October 2018, two sets of systematic
line-transect vessel surveys were conducted on the 4th, 11th, 16th
and 18th 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.
5.3.2
From these surveys, a total of 265.60 km of survey effort was
collected, with 99.8% 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).
5.3.3
Among the two survey areas, 95.50 km and 170.10 km of survey effort were collected from NEL and NWL survey areas
respectively. Moreover, the total survey effort conducted on primary lines was 192.70 km, while the effort on
secondary lines was 72.90 km.
5.3.4
During the two sets of monitoring surveys in October
2018only two groups of six Chinese White Dolphins were sighted (see Annex II of Appendix H). Both dolphin sightings were made in NWL,
while none was sighted in NEL. Moreover,
both dolphin groups were sighted during on-effort search, while one of them was
sighted on primary line (Annex
II of Appendix H).
Notably, none of the dolphin groups was associated with any operating fishing
vessel.
5.3.5
Distribution of the two dolphin sightings made in October
2018 is shown in Figure 6 of Appendix H.
One dolphin group was sighted just to the west of Lung Kwu Chau, while another sighting was made between Sha Chau and Pillar Point (Figure 6 of Appendix H).
5.3.6
During the Octoberˇ¦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 5.3 Individual 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: October 4th / 11th
|
0.0
|
0.0
|
Set
2: October 16th / 18th
|
0.0
|
0.0
|
NWL
|
Set
1: October 4th / 11th
|
0.0
|
0.0
|
Set
2: October 16th / 18th
|
1.6
|
3.3
|
Remark:
1. Dolphin Encounter Rates Deduced from the Two
Sets of Surveys (Two Surveys in Each Set) in October 2018 in Northeast Lantau
(NEL) and Northwest Lantau (NWL).
Table 5.4 Monthly
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)
|
Primary Lines Only
|
Both Primary and Secondary Lines
|
Primary Lines Only
|
Both Primary and Secondary Lines
|
Northeast
Lantau
|
0.0
|
0.0
|
0.0
|
0.0
|
Northwest
Lantau
|
0.8
|
1.2
|
1.7
|
3.5
|
Remark:
1.
Monthly Average Dolphin Encounter Rates (Sightings Per 100 km of
Survey Effort) from All Four Surveys Conducted in October 2018 on Primary Lines only as well as Both Primary
Lines and Secondary Lines in Northeast Lantau (NEL) and Northwest Lantau (NWL).
5.3.7
As there
were only two small groups of four and two dolphins being sighted respectively,
the average dolphin group size in October
2018 was just 3.0 individuals per group, which was lower than the averages in
the previous monitoring months (Annex
II of Appendix H).
Photo-identification Work
5.3.8
Five known individual dolphins
were sighted six times in total during the Octoberˇ¦s surveys (Annexes III and V of Appendix H). Four
of the five individuals were re-sighted only once during the monthly surveys,
while NL136 was re-sighted twice.
Conclusion
5.3.9
During this month of dolphin monitoring, no adverse impact from the
activities of this construction project on Chinese White Dolphins was
noticeable from general observations.
5.3.10
Due 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 2018) and the 3-month baseline monitoring period will be
made.
5.4.1 Buckland,
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.
5.4.2 Hung,
S. K. 2017. Monitoring of Marine Mammals in Hong
Kong waters: final report (2016-17).
An unpublished report submitted to the Agriculture, Fisheries and
Conservation Department, 162 pp.
5.4.3 Jefferson, T. A. 2000. Population biology of the Indo-Pacific
hump-backed dolphin in Hong Kong waters.
Wildlife Monographs 144:1-65.
6.1
Water Quality Monitoring
6.1.1 The mudflat
monitoring covered water quality monitoring data. Reference was made to the water quality
monitoring data of the representative water quality monitoring station (i.e.
SR3(N)) as in the EM&A Manual.
The water quality monitoring location (SR3(N)) is shown in Figure 2.1.
6.1.2 Impact water quality
monitoring in San Tau (monitoring station SR3(N)) was conducted in October 2018.
The monitoring parameters included dissolved oxygen (DO), turbidity and
suspended solids (SS).
6.1.3
The Impact monitoring results for SR3(N) were
extracted and summarised below:
Table 6.4 Impact Water Quality
Monitoring Results (Depth Average)
Date
|
Mid Ebb Tide
|
Mid Flood Tide
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
DO (mg/L)
|
Turbidity (NTU)
|
SS (mg/L)
|
01-Oct-2018
|
5.9
|
4.7
|
8.1
|
5.9
|
5.0
|
8.2
|
03-Oct-2018
|
5.5
|
3.5
|
5.1
|
5.8
|
7.9
|
9.2
|
05-Oct-2018
|
5.6
|
9.6
|
7.5
|
6.2
|
10.3
|
13.4
|
08-Oct-2018
|
6.1
|
10.2
|
6.1
|
5.8
|
6.4
|
5.9
|
10-Oct-2018
|
5.8
|
8.7
|
6.3
|
5.8
|
8.6
|
9.8
|
12-Oct-2018
|
6.3
|
8.0
|
8.4
|
5.8
|
9.2
|
12.9
|
15-Oct-2018
|
5.9
|
7.5
|
6.8
|
5.9
|
8.4
|
4.3
|
17-Oct-2018
|
6.3
|
4.9
|
4.0
|
6.0
|
3.1
|
2.8
|
19-Oct-2018
|
6.4
|
2.3
|
1.2
|
6.6
|
4.2
|
5.4
|
22-Oct-2018
|
6.5
|
4.5
|
2.5
|
6.6
|
6.3
|
7.1
|
24-Oct-2018
|
6.4
|
2.6
|
6.6
|
6.0
|
3.2
|
7.9
|
26-Oct-2018
|
6.5
|
3.2
|
5.9
|
6.3
|
2.8
|
4.6
|
29-Oct-2018
|
6.6
|
1.5
|
5.3
|
6.7
|
3.1
|
9.5
|
31-Oct-2018
|
6.5
|
1.5
|
3.3
|
7.2
|
2.5
|
4.8
|
Average
|
6.2
|
5.2
|
5.5
|
6.2
|
5.8
|
7.6
|
Sampling Zone
6.2.1
In order to collect baseline
information of mudflats in the study site, the study site was divided into
three sampling zones (labeled as TC1, TC2, TC3) in Tung Chung Bay and one zone
in San Tau (labeled as ST) (Figure 2.1
of Appendix 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
and October 2018 (totally 6 sampling days between 20nd and 21st
September 2018).
6.2.2
Since 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 government agency
units.
Horseshoe Crabs
6.2.3
Active 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 20th (for TC3 and ST) and 23rd (for TC1 and
TC2) September 2018. The weather was generally hot and sunny on all survey
days.
6.2.4
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 inhabiting sub-tidal environment while it forages on intertidal shore
occasionally during high tide period. If it is tangled by the trash net for few
days, it may die due to starvation or overheat during low tide period. These
trash gill nets are definitely ˇĄfatal trapˇ¦ for the horseshoe crabs and other
marine life. Manual clean-up should be implemented as soon as possible by
responsible government agency units.
Seagrass Beds
6.2.5
Active 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 20th (for TC3 and
ST) and 23rd (for TC1 and TC2) September 2018. The weather was generally hot and sunny on all survey days
.
Intertidal Soft Shore Communities
6.2.6 The intertidal soft shore
community surveys were conducted in low tide period 6th (for TC2), 7th
(for ST), 20th (for TC1) and 21st (for TC3) October 2018.
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.
6.2.7 Inside a quadrat, any visible epifauna were collected
and were in-situ identified to the
lowest practical taxonomical resolution. Whenever possible a hand core sample (10 cm internal diameter ´ 20 cm depth) of sediments was collected in the quadrat. The core sample was gently washed through a sieve of mesh size 2.0 mm in-situ. Any visible infauna were collected and identified. Finally
the top 5 cm surface sediments was dug for visible infauna in the quadrat
regardless of hand core sample was taken.
6.2.8 All collected fauna were released after recording except some tiny
individuals that are too small to be identified on site. These
tiny individuals were taken to laboratory for identification under dissecting
microscope.
6.2.9 The
taxonomic classification was conducted in accordance to the following
references: Polychaetes: Fauchald (1977), Yang and Sun (1988); Arthropods: Dai
and Yang (1991), Dong (1991); Mollusks: Chan and Caley (2003), Qi (2004), AFCD (2018).
Data Analysis
6.2.10 Data collected from
direct search and core sampling was pooled in every quadrat for data analysis.
Shannon-Weaver Diversity Index (Hˇ¦)
and Pielouˇ¦s Species Evenness (J)
were calculated for every quadrat using the formulae below,
Hˇ¦= -ŁU ( Ni / N ) ln ( Ni / N ) (Shannon and Weaver, 1963)
J = Hˇ¦ / 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.
6.3.1
In 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 6.5 Event
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 are
significantly 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;
Implement the agreed
measures.
|
Notes:
ET ˇV Environmental Team
IEC ˇV Independent
Environmental Checker
SO ˇV Supervising Officer
Horseshoe Crabs
6.4.1
In the
present survey, two species of horseshoe crab Carcinoscorpius rotundicauda (total 115 ind.) and Tachypleus tridentatus (total 37 ind.) were recorded. The recorded individuals were mainly
distributed along the shoreline from TC3 to ST. Grouping of 2-25 individuals
was usually observed on
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.
6.4.2
Table 3.1 of
Appendix I summarizes
the survey results of horseshoe crab in the present survey. For Carcinoscorpius rotundicauda, highest number of individuals
were found in ST followed by TC3 and TC1. In ST, 64 individuals were found with average body size 34.83 mm (24.87-62.79 mm) resulting in
moderate search record (10.7 ind. hr-1 person-1). In TC1, there were 17 individuals average body size 44.03 mm (prosomal
width ranged 34.37-65.67 mm). In TC3, there were 33 individuals with average body size 32.15 mm
(9.96-62.94 mm). The search records (4.3-5.5 ind. hr-1 person-1) were at low-moderate level in both zones. In TC2, there was only 1
individual with body size 47.44 mm resulting in very low search record (0.3 ind. hr-1 person-1).
6.4.3
There was similar pattern of survey results for Tachypleus tridentatus. Highest number of individuals were found in ST (23 ind.) with average body
size 50.16 mm (38.90-70.97
mm),
resulting in low-moderate search record (3.8 ind. hr-1 person-1).
In TC1 and TC3, few individuals (6-8) were found with average body
size 38.70-57.00 mm (prosomal width ranged 25.78 - 69.99 mm). The search record
was at low level (1.3 -
1.5 ind. hr-1 person-1). No individual was found in TC2.
6.4.4
In 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 Jun. 2017, mating pairs of Carcinoscorpius
rotundicauda were also found in TC2 (male 175.27 mm, female 143.51 mm) and
TC3 (male 182.08 mm, female 145.63 mm) (Figure 3.2 of Appendix I). In Dec. 2017 and Jun. 2018 , one mating pair was of Carcinoscorpius
rotundicauda was found in TC3 (Dec. 2017: male 127.80 mm, female 144.61 mm; Jun. 2018: male 139 mm, female 149 mm). Figure
3.2 of Appendix I shows the photographic records of all mating pairs found. The recorded 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. These mating pairs indicated that
breeding of horseshoe crab could be possible along the coast of Tung Chung Wan
rather than ST only, as long as suitable substratum was available. Based on the frequency of encounter, the shoreline between TC3 and
ST should be more suitable mating ground. Moreover suitable breeding period was believed in wet season (Mar -
Sep.) because tiny individuals (i.e. newly hatched) were usually recorded in
Jun. and Sep. every year. In present survey (Sep. 2018), two newly hatched
individuals were also found in TC1 and TC2 (prosomal width 6.00-6.87 mm) (Figure 3.4 of Appendix I)
while species identification was not possible.
6.4.5
Despite of mating pair, there
were occasional records of large individuals of Carcinoscorpius rotundicauda (prosomal width ranged 114.45 - 178.67 mm, either single or in
pair) and Tachypleus tridentatus (prosomal
width 103 mm) (Figure
3.3 of Appendix I). 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.
6.4.6 No 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.
6.4.7 The artificial bred individuals, if found,
would be excluded from the results of present monitoring programme in order to
reflect the changes of natural population. However, the mark on their prosoma
might have been detached during moulting after a certain period of release. The
artificially released individuals were no longer distinguishable from the
natural population without the specific chip sensor. The survey data collected
would possibly cover both natural population and artificially bred individuals.
Population difference among the sampling
zones
6.4.8 Figures 3.5 and 3.6 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.
6.4.9 For 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 SeptemberOne 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). From Dec. 2017 to Sep. 2018 (present survey), the search records of both species increased again to low-moderate level in TC3 and ST. Relatively higher population fluctuation of Tachypleus tridentatus was observed in TC3
6.4.10 For TC1, the search record was at low to moderate level throughout the
monitoring period. The change of Carcinoscorpius rotundicauda was relatively more variable than that of Tachypleus tridentatus. Relatively, the search record
was very low in TC2 (2 ind. in Sep. 2013; 1 ind. in Mar.-Sep. 2014, Mar.-Jun.
2015; 4 ind. in Sep. 2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016, 1 ind.
from Mar.-Sep. 2017; 3 ind. in Jun. 2018;1 ind. In Sep. 2018).
6.4.11 About
the body size, larger individuals of Carcinoscorpius rotundicauda were usually found in ST and TC1 relative to those in TC3 from Sep. 2012
to Jun. 2017. But the body size was higher in TC3 and ST followed by TC1 from
Sep. 2017 to Jun. 2018. In Sep. 2018 (present survey), larger individuals were
found in ST and TC1 again. For Tachypleus tridentatus, larger
individuals were usually found in ST and TC3 followed by TC1 throughout the
monitoring period.
6.4.12 In general, it was obvious that the
shoreline along 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 once found in TC2, the hatching rate and survival rate of newly
hatched individuals were believed very low.
Seasonal
variation of horseshoe crab population
6.4.13
Throughout the monitoring period, the search
record of horseshoe crab declined obviously during dry season especially
December (Figures 3.4 and 3.5 of Appendix
I). 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 search 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 ˘XC 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 ˘XC during dawn on 19 Dec). The horseshoe crab activity would decrease gradually with the colder
climate. In Dec. 2017, the weather was cold (13-15 ºC during dawn) that very
few individuals of both species could be found as mentioned above.
6.4.14
From 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. In 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 Chung 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).
6.4.15 For 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. From Sep. 2017 to Sep. 2018 (present survey), moderate
numbers of individual were found in TC3 and ST indicating a stable population
size. Lower population size compared with that in Jun. 2017 was believed the
cause of natural mortality.
6.4.16
Recently, Carcinoscorpius
rotundicauda was a more common horseshoe crab species in Tung Chung Wan. It
was recorded in the four sampling zones while the majority of population
located in TC3 and ST. Due to potential breeding last year, Tachypleus 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
6.4.17
Figure 3.7 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 Sep. 2018,
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.
6.4.18 For Tachypleus
tridentatusthe 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, 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). From Dec. 2017 to Sep. 2018 (present survey), increasing
trend was noted again. Across the whole monitoring
period, the larger juveniles (upper whisker) usually reached 60-80 mm in
prosomal width, even 90 mm occasionally. Juveniles reaching this size might
gradually migrate to sub-tidal habitats.
Box plot of horseshoe crab populations in ST
6.4.19
Figure 3.8 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.
6.4.20
For Tachypleus tridentatusa 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, it indicated new round of spawning. From Sep. 2017 to Jun. 2018, the major size range increased slightly
from 40-50 mm to 45-60 mm indicating a continuous growth. In Sep. 2018 (present
survey), decrease of major size was noted again that might reflect new round of
spawning. Throughout the monitoring period, the larger junveniles ranged 60-80
mm in prosomal width. Juveniles reaching this size would gradually migrate to
sub-tidal habitats.
6.4.21 As a summary for horseshoe crab
populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014 to 2018 while the spawning
time should be in spring. 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. From 2016 to 2018, new rounds of spawning were recorded in ST while
increasing number of individuals and body size was noticed.
Impact of the HKLR project
Seagrass Beds
6.4.23 Since the commencement of the
EM&A monitoring programme, two species of seagrass Halophila ovalis and Zostera japonica were recorded in TC3 and ST (Figure 3.9 of Appendix
I). In general, Halophila ovalis was occasionally found in TC3
in few, small to medium patches. But it was commonly found in ST in medium to
large seagrass bed. Moreover it had sometimes grown extensively and had covered
significant mudflat area at 0.5-2.0 m above C.D. between TC3 and ST. Another seagrass species Zostera
japonica was found in ST only. It was
relatively lower in vegetation area and was co-existing with Halophila ovalis nearby the mangrove strand at
2.0 m above C.D...
6.4.24 Table 3.2 of Appendix I summarizes the
results of seagrass beds survey.
In ST, two small sized
patches of Halophila
ovalis were found while the total
seagrass bed area was about 22.5 m2 (Figure 3.10 of Appendix I). The
relatively larger patch had area ~12 m2 in high vegetation coverage 80%, located at tidal zone 1.5-2.0 m above
C.D nearby mangrove plantation. At vicinity, there was a small, horizontal
strand (~10.5 m2, low coverage 5%). Another
seagrass species Zostera japonica was not found in present survey.
Annex II of Appendix I shows the
complete record of seagrass survey.
6.4.25 According to the previous results, majority of seagrass bed was confined
in ST, the temporal change of both seagrass species were investigated in
details:
Temporal
variation of seagrass beds
6.4.26 Figure
3.11 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. And it
was no longer co-exisitng 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. From Sep. 2017 to Sep.
2018 (present survey), no seagrass patch of Zostera japonica was found.
6.4.27 For Halophila ovalis, it was recorded as 3-4 medium to
large patches (area 18.9-251.7 m2; vegetation coverage 50-80%)
beside the mangrove vegetation at tidal level 2 m above C.D. in Sep. 2012
(first survey). The total
seagrass bed area grew steadily from 332.3 m2 in Sep. 2012 to 727.4
m2 in Dec. 2013. Flowers were observed in the largest patch during its
flowering period. In Mar.
2014, 31 small to medium patches were newly recorded (variable area 1-72 m2
per patch, vegetation coverage 40-80% per patch) in lower tidal zone between
1.0 and 1.5 m above C.D. The total seagrass area increased further to 1350 m2.
In Jun. 2014, these small and medium patches grew and extended to each other.
These patches were no longer distinguishable and were covering a significant
mudflat area of ST. It was generally grouped into 4 large patches (1116 ˇV 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 large 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.
6.4.28 In
Dec. 2014, all the seagrass patches of Halophila
ovalis disappeared in ST. Figure 3.12
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
6.4.29 Typhoon or strong water current was suggested as one unfavourable
condition to Halophila ovalis (Fong,
1998). As mentioned above, there were two tropical cyclone records in Hong Kong
in Sep. 2014. The strong water current caused by the cyclones might have given
damage to the seagrass beds.
6.4.30
Prolonged
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).
6.4.31
In order to investigate any deterioration of
water quality (e.g. more turbid) in ST, the water quality measurement results
at two closest monitoring stations SR3 and IS5 of the EM&A programme were
obtained from the water quality monitoring team. Based on the results from June
to December 2014, the overall water quality was in normal fluctuation except
there was one exceedance of suspended solids (SS) at both stations in September.
On 10th 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 stationˇ¦s
reading) and Limit Level (≤34.4 mg/L and
130% of upstream control stationˇ¦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 ˇĄNotifications of Environmental
Quality Limits Exceedancesˇ¦ 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.
6.4.32
Based 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
6.4.33
Figure 3.12 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 (Fig. 3.10). 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). The whole
recolonization process took about 2.5 years.
Re-disappearance of seagrass bed
6.4.34
In Sep 2017, the whole seagrass
bed of Halophila ovalis disappeared
again along the shore of TC3 and ST (Figure
3.12 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.
6.4.35
Between 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).
6.4.36
According 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.
6.4.37
Overall, 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 whole recolonization process (from few, small patches to extensive
strand) would be gradual lasting 2
years. From Dec. 2017 to Mar. 2018, there was still no recolonization of few,
small patches of seagrass at the usual location. It was different from previous
re-colonization (Mar. 2015 - Jun. 2017). Until Jun. 2018 , new, small-medium
seagrass patches were found at the usual location (seaward side of mangrove
plantation at 2.0 m C.D.) again, indicating the recolonization. However the seagrass bed area decreased
sharply to 22.5 m2 in Sep. 2018 (present survey). Again it was believed
the hit of super cyclone in Sep. 2018 (Mangkhut on 16th Sep., highest
signal 10). It was expected that the recolonization
would occour later and slower than previous round (more than 2 years)
Impact of the HKLR
project
6.4.38 It was
the 24th survey of the EM&A programme during the construction
period. Throughout the monitoring period,
the disappearance of seagrass beds was believed the cause of cyclone hits
rather than impact of HKLR project. Slow and gradual recolonization of seagrass was expected in the following months.
Intertidal Soft Shore Communities
6.4.39 Table 3.3 and Figure 3.13 of Appendix I show the substratum types along the horizontal
transect at every tidal level in all sampling zones. The
relative distribution of substratum types was estimated by categorizing the substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random quadrats along the horizontal transect.
The distribution of substratum types varied among tidal levels and sampling zones:
ˇP
In TC1, high percentages of ˇĄGravels and Bouldersˇ¦ (70-80%) were
recorded at all tidal levels followed by ˇĄSandsˇ¦ (20%).
ˇP
In TC2, high percentages of ˇĄSandsˇ¦ (60-70%) were recorded at high and
mid tidal levels followed by ˇĄSoft mudˇ¦ (20-40%). At low tidal level, the major
substratum type was 'Soft mud' (80%) followed by ˇĄSandsˇ¦ (20%).
ˇP
In TC3, the main substratum was ˇĄSandsˇ¦ (100%) at high and mid tidal
levels while it was ˇĄGravels and Bouldersˇ¦ (100%) at low tidal level.
ˇP
In ST, ˇĄGravels and Bouldersˇ¦ was the main substratum (90-100%) at high
and mid tidal levels. At low tidal level, there was higher percentage of ˇĄSandsˇ¦
(60%) followed by 'Soft mud' (30%).
6.4.40 There was neither consistent
vertical nor horizontal zonation pattern of substratum type in all sampling
zones. Such heterogeneous variation should be caused by different hydrology
(e.g. wave in different direction and intensity) received by the four sampling
zones.
6.4.41 Table 3.4 of Appendix I lists
the total abundance, density and number of taxon of every phylum in
this survey. A total of 17453 individuals
were recorded. Mollusca was clearly the
most abundant phylum (total abundance 17166 ind., density 572 ind. m-2, relative abundance 98.4 %). The second and third abundant phya were Arthropoda (201 ind., 7 ind. m-2, 1.2 %) and Annelida (60 ind., 2 ind. m-2, 0.3 %) respectively. Relatively other phyla were very low in abundances (density £1 ind. m-2, relative abundance £0.0 %). Moreover, the most diverse phylum was Mollusca (31 taxa)
followed by Arthropoda (9
taxa) and Annelida (8 taxa). There was 1-2 taxa recorded only for other phyla..
6.4.42
The taxonomic resolution and complete list of recorded fauna are shown
in Annexes IV and V of Appendix I respectively. As reported in Jun. 2018, taxonomic revision of three potamidid
snail species was conducted according to the latest identification key
published by Agriculture, Fisheries and Conservation Department (details see
AFCD, 2018), the species names of following gastropod species were revised::
ˇP
Cerithidea cingulata was revised as Pirenella asiatica
ˇP
Cerithidea djadjariensis was revised as Pirenella incisa
ˇP
Cerithidea rhizophorarum was revised as Cerithidea moerchii
In
present survey, taxonomic revision was conducted on
another snail species while the specie name was revised.:
ˇP
Batillaria bornii was revised as Clypeomorus
bifasciata
6.4.43 Table 3.5 of Appendix I shows
the number of individual, relative abundance and density of each phylum in every sampling zone. The total abundance (2357-6005
ind.) varied among the four sampling zones while the phyla distributions were similar. In general, Mollusca was the
most dominant phylum (no. of individuals: 2243-5909
ind.; relative abundance 95.2-99.4 %; density 299-788 ind. m-2). Other phyla were much lower in number of individuals. Arthropoda (26-76
ind.; 0.5-3.2 %; 3-10 ind. m-2) and Annelida (2-33 ind.; 0.1-1.4 %; 0-4 ind. m-2)
were the second and third abundant phylum respectively.
Relatively other phyla were very low in
abundance in all sampling zones.
Dominant species in every sampling zone
6.4.44
Table 3.6 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 regarded as common species..
6.4.45
In TC1, the substratum was mainly ˇĄGravels
and Bouldersˇ¦ at all tidal levels. It was clearly dominated by gastropod Batillaria multiformis (651 ind. m-2, relative abundance 72 %) at very high
density. At mid tidal level, gastropod Batillaria
multiformis (361
ind. m-2, 57 %) was still dominant followed by gastropod Monodonta
labio (117 ind. m-2, 18 %) at low-moderate density. At low tidal level,
there were few abundant gastropods Batillaria multiformis (164 ind. m-2,
29 %), Monodonta labio (136 ind. m-2, 24 %) and Pirenella
incisa (56 ind. m-2, 10 %) at low-moderate densities. Moreover,
rock oyster Saccostrea cucullata (104 ind. m-2, 19 %, attached
on boulders) was also abundant. .
6.4.46
In TC2, the
substratum types were either 'Sands' or 'Soft mud' at high
and mid tidal levels. Gastropods Pirenella asiatica (49-149 ind. m-2,
15-30%), Pirenella incisa (48-118 ind. m-2, 14-24%), Batillaria
zonalis (80-117 ind. m-2, 16-35%) were
the abundant taxa at low-moderate densities. Moreover rock oyster Saccostrea
cucullata (56-63 ind. m-2, 12-19%, attached on boulders) was
also abundant at low densities. At low tidal level (main substratum type ˇĄSoft
mudˇ¦), there was only one abundant gastropod Batillaria zonalis (65 ind. m-2, 56 %) at low
density.
6.4.47
In TC3, the substratum types were mainly ˇĄSandsˇ¦ at high and mid tidal
levels. Gastropod Pirenella incisa (352-383 ind. m-2, 41-49 %) was dominant followed by gastropod
Pirenella asiatica (134-194
ind. m-2, 14-27 %) at low-moderate density. Moreover gastropod Batillaria
multiformis (368 ind. m-2, 40 %) was abundant at high tidal
level. At low tidal level (major
substratum: ˇĄGravels and Bouldersˇ¦), gastropod Monodonta labio (289 ind. m-2, 38 %) and rock oyster Saccostrea
cucullata (258 ind. m-2, 34 %, attached on boulders) were
abundant at moderate densities, followed by gastropod
Lunella coronata (87 ind. m-2, 11 %)..
6.4.48
In ST, the major substratum types were mainly ˇĄGravels
and Bouldersˇ¦ at high and mid tidal levels. At high tidal level, gastropod Monodonta labio (215 ind. m-2, 36 %)
was the most abundant at moderate density. Other abundant gastropods Batillaria
multiformis (131 ind. m-2, 22 %) and Clypeomorus bifasciata
(60 ind. m-2, 10 %) were at low-moderate densities. At mid tidal
level, rock oyster Saccostrea cucullata (166 ind. m-2, 25%) and Monodonta labio (163 ind. m-2, 25 %)
were abundant at low-moderate densities followed by other gastropods Lunella
coronata (97 ind. m-2, 15 %) and Pirenella asiatica (76 ind.
m-2, 12 %). At low tidal level (major
substratum types: ˇĄSandsˇ¦ and 'Soft mud'), there were two abundant gastropods Pirenella incisa (70 ind. m-2, 25 %) and Lunella coronata (58 ind. m-2,
21 %). Rock oyster Saccostrea cucullata (42 ind. m-2, 15 %)
was also common..
6.4.49 In general, there was no consistent zonation pattern of
species distribution across all sampling zones and tidal levels. The
species distribution should be determined by the type of substratum primarily.
In general, gastropods Batillaria multiformis (total
number of individuals: 4532 ind., relative abundance 26.0 %), Pirenella incisa (3005
ind., 17.2 %), , Pirenella asiatica (1970
ind., 11.3 %) and Batillaria zonalis (907 ind.,
5.2 %) were
the most commonly occurring species on sandy and soft mud substrata. Rock oyster Saccostrea
cucullata (2135 ind., 12.2 %), gastropods Monodonta
labio (2513 ind., 14.4 %) and Lunella coronata (853
ind., 4.9 %) were the
commonly occurring species inhabiting gravel and boulders substratum..
Biodiversity and abundance of soft shore communities
6.4.50 Table 3.7 of Appendix
I shows the mean values of species number,
density, biodiversity index Hˇ¦ 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.
6.4.51 Among the sampling zones, the mean species number of ST (10 spp. 0.25
m-2) was slightly higher than other sampling zones (7-8 spp. 0.25 m-2).
The mean density of TC1 and TC3 (700-801 ind. m-2) were higher than ST
(513 ind. m-2) followed by TC2 (314 ind. m-2). Overall,
ST was relatively higher in H' (1.6)
due to higher species number and even taxa distribution. In TC1 and TC3, the
higher densities were mainly accounted by 1-2 abundant
gastropods while it resulted in lower Hˇ¦
(1.2). In TC2, lower species number and density also resulted in lower H' (1.2). The J was similar (0.6-0.7) among all sampling zones..
6.4.52 Among the tidal levels, there were slightly increasing trends of
mean species number and H' from high
to low tidal level in TC1 and TC3 but vice versa in TC2 and ST. A general
decreasing trend of mean density was observed from high to low tidal level in
all sampling zones. No difference of J
was found between the tidal levels. In general, the spatial differences of
these biological parameters were highly related to substratum types.
6.4.53 Figures 3.14 to 3.17 of Appendix I show the temporal changes of mean species number, mean density,
Hˇ¦ 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.
6.4.54 From Jun. to Dec. 2017, there
were steady decreasing trends of mean species number and density in TC2, TC3
and ST regardless of tidal levels. It might be an unfavourable change
reflecting environmental stresses. The heat stress and serial cyclone hit were believed
the causes during the wet season of 2017. From Mar. to Sep. 2018 (present
survey), increases of mean species number and density were observed in all
sampling zones. It indicated the recovery of intertidal community.
Impact
of the HKLR project
6.5.1 AFCD, 2018. Potamidid
Snails in Hong Kong Mangrove. Agriculture, Fisheries and Conservation
Department Newsletter - Hong Kong Biodiversity Issue #25, 2-11
6.5.2 Chan,
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.
6.5.3 Dai,
A.Y., Yang, S.L., 1991. Crabs of the China Seas. China Ocean Press. Beijing.
6.5.4 Dong,
Y.M., 1991. Fauna of ZheJiang Crustacea. Zhejiang Science and Technology
Publishing House. ZheJiang.
6.5.5 EPD,
1997. Technical Memorandum on Environmental Impact Assessment Process (1st
edition). Environmental Protection Department, HKSAR Government.
6.5.6 Fauchald,
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..
6.5.7 Fong,
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.
6.5.8 Li,
H.Y., 2008. The Conservation of Horseshoe Crabs in Hong Kong. MPhil Thesis,
City University of Hong Kong, pp 277.
6.5.9 Longstaff,
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.
6.5.10 Longstaff,
B.J., Loneragan, N.R., Oˇ¦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.
6.5.11 Nakaoka,
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.
6.5.12 Pielou,
E.C., 1966. Shannonˇ¦s formula as a measure of species diversity: its use and
misuse. American Naturalist 100, 463-465.
6.5.13 Qi,
Z.Y., 2004. Seashells of China. China Ocean Press. Beijing, China.
6.5.14 Qin,
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.
6.5.15 Shannon,
C.E., Weaver, W., 1963. The Mathematical Theory of Communication. Urbana:
University of Illinois Press, USA.
6.5.16 Shin,
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.
6.5.17 Supanwanid,
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.
6.5.18 Vermaat,
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.
6.5.19 Yang,
D.J, Sun, R.P., 1988. Polychaetous annelids commonly seen from the Chinese
waters (Chinese version). China Agriculture Press, China
.
7
Environmental Site Inspection and Audit
7.1.1
Site 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 3, 10, 16 and 26 October 2018.
7.1.2 A summary of observations
found during the site inspections and the follow up actions taken by the Contractor are described in Table 7.1.
Table 7.1 Summary
of Environmental Site Inspections
Date of Audit
|
Observations
|
Actions Taken by Contractor / Recommendation
|
Date of Observations Closed
|
28 Sep 2018
|
1. Waste was observed at S15.
2. Stagnant water was observed at S15.
|
1. The waste was removed at S15.
2.
The stagnant water
was removed at S15.
|
3 Oct 2018
|
3. Drip tray was not provided for a generator
at N4.
4. Stagnant water was observed inside the drip tray for a generator at
N4.
|
The Contractor was recommended to:
3. provide drip tray for the
generator at N4.
4. remove the stagnant water
inside the drip tray at N4.
|
|
3 Oct 2018
|
1. Chemical containers were observed without
drip tray at N4.
2. Waste was observed at N4.
|
1.
The chemical containers were
removed at N4.
2.
The
waste was removed at N4.
|
10 Oct 2018
|
10 Oct 2018
|
1. Stagnant water was observed inside I-beam
at N4.
2. Waste was accumulated on the ground at N4.
3. A chemical container was observed without
drip tray at N4.
|
1. The stagnant water was removed from the I-beam at N4.
2. The accumulated waste was removed on the ground at N4.
3.
The chemical
container was removed at N4.
|
16 Oct 2018
|
16
Oct 2018
|
1. Waste was observed at LCSD.
2. Waste was observed at N4.
3. Chemical containers were observed without drip tray at WA4.
|
1.
The waste
was removed at LSCD.
2.
The
waste was removed at N4.
3.
The chemical containers were removed at WA4.
|
26 Oct 2018
|
26 Oct 2018
|
1. Stagnant water was observed at N4.
2. Inert waste was observed at N4.
3. Dry stockpile was observed at S7.
|
The Contractor was
recommended to:
1. remove the stagnant water at N4.
2. remove the inert waste at
N4.
3. spray water to the dry
stockpile at S7.
|
Follow-up
actions for the observations issued for the last weekly site inspection of the reporting month will be inspected during the next
site inspection.
|
7.1.3 The 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 inspection.
7.2
Advice on the
Solid and Liquid Waste Management Status
7.2.1 The Contractor
registered as a chemical waste producer for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
7.2.2
Monthly summary of waste flow table is detailed in Appendix J.
7.2.3 The Contractor was reminded that
chemical waste containers should be properly treated and stored temporarily in
designated chemical waste storage area on site in accordance with the Code of
Practice on the Packaging, Labelling and Storage of Chemical Wastes.
7.3.1 The valid
environmental licenses and permits during the reporting month are summarized in
Appendix L.
7.4
Implementation Status of Environmental
Mitigation Measures
7.4.1 In response to the
site audit findings, the Contractors have rectified most of the observations as identified during environmental site
inspections during the reporting month. Follow-up actions for outstanding
observations will be inspected during the next site inspections.
7.4.2 A summary of the
Implementation Schedule of Environmental Mitigation Measures (EMIS) is
presented in Appendix M. Most of the
necessary mitigation measures were implemented properly.
7.4.3 Regular marine travel route for
marine vessels were implemented properly in accordance to the submitted plan
and relevant records were kept properly.
7.4.4 Dolphin Watching Plan was
implemented during the reporting month. No dolphins inside the silt curtain
were observed. The relevant records were kept properly.
7.5.1 For air quality, three Action
Level exceedances of 1-hr TSP were recorded at AMS5 during the reporting month.
No Limit Level exceedance of 24-hrTSP were recorded at AMS5 during the
reporting month.
7.5.2 No Action and Limit Level exceedances of
1-hr TSP and 24-hr TSP were recorded at AMS6 during the reporting month.
7.5.3 For construction noise, no Action
and Limit Level exceedances were recorded at the monitoring station during the
reporting month.
7.5.1
For marine water quality monitoring, no Action
Level and Limit Level exceedances of dissolved oxygen level and turbidity level
were recorded during the reporting month. During the reporting month, an
Action Level exceedance of suspended solids level was recorded. No Limit Level
exceedances of suspended solids level were recorded.
7.6
Summary of
Complaints, Notification of Summons and Successful Prosecution
7.6.1
There was no complaint received in relation to the environmental impacts
during the reporting month. The details of cumulative statistics of
Environmental Complaints are provided in
Appendix K.
7.6.2
No notification of summons and
prosecution was received during the reporting period. Statistics on
notifications of summons and successful prosecutions are summarized
in Appendix N.
8.1.1 As informed by the Contractor, the major
construction activities for November 2018 are summarized in Table 8.1.
Table 8.1 Construction
Activities for November 2018
Site Area
|
Description
of Activities
|
Portion X
|
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)
|
Airport Road
|
Works for Diversion of
Airport Road
|
Airport Road / Airport
Express Line/ East Coast Road
|
Establishment of Site
Access
|
Airport Road
|
E&M/
Backfilling works for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)
|
Portion X
|
E&M/
Backfilling works for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)
|
Portion X
|
Finishing works for
Highway Operation and Maintenance Area Building
|
West Portal
|
Finishing Works for
Scenic Hill Tunnel West Portal Ventilation Building
|
8.2.1 1.2 The tentative schedule for
environmental monitoring in November 2018 is provided in Appendix D.
9.1.1
The construction phase and EM&A programme of the
Contract commenced on 17 October 2012. This is the seventy-third 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 31 October 2018.
Air Quality
9.1.2 For air quality, three Action
Level exceedance of 1-hr TSP were recorded at AMS5 during the reporting month.
No Limit Level exceedance of 24-hrTSP were recorded at AMS5 during the
reporting month.
9.1.3 No Action and Limit Level exceedances of
1-hr TSP and 24-hr TSP were recorded at AMS6 during the reporting month.
Noise
9.1.4 For construction
noise, no Action and Limit Level exceedances were recorded at the monitoring
station during the reporting month.
Water Quality
9.1.5
For marine water quality monitoring, no Action
Level and Limit Level exceedances of dissolved oxygen level and turbidity level
were recorded during the reporting month. During the reporting month, an
Action Level exceedance of suspended solids level was recorded. No Limit Level
exceedances of suspended solids level were recorded.
Dolphin
9.1.6 During the Octoberˇ¦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.
9.1.7
Due 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
ˇV November 2018) and baseline monitoring period
(3-month period) will be made.
Mudflat
Environmental Site Inspection and
Audit
9.1.9
Environmental site inspections were carried out on 3, 10, 16 and 26 October 2018. Recommendations on remedial actions were given to the
Contractors for the deficiencies identified during the site inspections.
9.1.10
There was no complaint received
in relation to the environmental impact during the reporting period.
9.1.11
No
notification of summons and prosecution was received during the reporting
period.