Contract No.
HY/2011/03
Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road
Section between Scenic Hill and Hong Kong Boundary Crossing
Facilities
Monthly EM&A Report No.84 (September 2019)
15 October 2019
Revision
1
Main
Contractor Designer
Contents
Executive Summary
1...... Introduction. 1
1.1 Basic
Project Information.. 1
1.2 Project
Organisation.. 2
1.3 Construction
Programme.. 2
1.4 Construction
Works Undertaken During the Reporting Month.. 2
2....... Air Quality Monitoring.. 4
2.1 Monitoring
Requirements. 4
2.2 Monitoring
Equipment 4
2.3 Monitoring
Locations. 4
2.4 Monitoring
Parameters, Frequency and Duration.. 5
2.5 Monitoring
Methodology.. 5
2.6 Monitoring
Schedule for the Reporting Month.. 7
2.7 Monitoring
Results. 7
3....... Noise
Monitoring.. 9
3.1 Monitoring
Requirements. 9
3.2 Monitoring
Equipment 9
3.3 Monitoring
Locations. 9
3.4 Monitoring
Parameters, Frequency and Duration.. 9
3.5 Monitoring
Methodology.. 10
3.6 Monitoring
Schedule for the Reporting Month.. 10
3.7 Monitoring
Results. 11
4....... Water
Quality Monitoring.. 12
4.1 Monitoring
Requirements. 12
4.2 Monitoring
Equipment 13
4.3 Monitoring
Parameters, Frequency and Duration.. 13
4.4 Monitoring
Locations. 14
4.5 Monitoring
Methodology.. 15
4.6 Monitoring
Schedule for the Reporting Month.. 16
4.7 Monitoring
Results. 16
5....... Dolphin
Monitoring. 19
5.1 Monitoring Requirements. 19
5.2 Monitoring
Methodology.. 19
5.3 Monitoring
Results. 21
5.4 Reference.. 23
6....... Mudflat
Monitoring.. 24
6.1 Sedimentation
Rate Monitoring.. 24
6.2 Water
Quality Monitoring.. 25
6.3 Mudflat
Ecology Monitoring Methodology.. 26
6.4 Event
and Action Plan for Mudflat Monitoring.. 27
6.5 Mudflat
Ecology Monitoring Results and Conclusion.. 28
6.6 Reference.. 39
7....... Environmental Site
Inspection and Audit 41
7.1 Site
Inspection.. 41
7.2 Advice
on the Solid and Liquid Waste Management Status. 42
7.3 Environmental
Licenses and Permits. 42
7.4 Implementation
Status of Environmental Mitigation Measures. 43
7.5 Summary
of Exceedances of the Environmental Quality Performance Limit 43
7.6 Summary
of Complaints, Notification of Summons and Successful Prosecution.. 43
8....... Future
Key Issues. 44
8.1 Construction
Programme for the Coming Months. 44
8.2 Environmental
Monitoring Schedule for the Coming Month.. 44
9....... Conclusions. 45
9.1 Conclusions. 45
Figures
Figure 1.1 Location of the Site
Figure 2.1 Environmental Monitoring Stations
Figure 6.1 Mudflat
Survey Areas
Appendices
Appendix A Environmental
Management Structure
Appendix B Construction
Programme
Appendix C Calibration
Certificates
Appendix D Monitoring
Schedule
Appendix E Monitoring
Data and Graphical Plots
Appendix F Event
and Action Plan
Appendix G Wind
Data
Appendix H Dolphin
Monitoring Results
Appendix I Mudflat
Monitoring Results
Appendix J Waste
Flow Table
Appendix K Cumulative
Statistics on Complaints
Appendix L Environmental
Licenses and Permits
Appendix M Implementation
Schedule of Environmental Mitigation Measures
Appendix N Records
of ˇ§Notification of Environmental Quality Limit Exceedancesˇ¨ and Record of ˇ§Notification of Summons and
Prosecutionsˇ¨
Appendix O Location
of Works Areas
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 eighty-fourth Monthly EM&A report for the Contract which summarizes the monitoring
results and audit findings of the EM&A programme during the reporting
period from 1 to 30 September
2019.
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
|
4,
10, 16, 20, 26 September 2019
|
24-hr TSP Monitoring
|
3,
9, 13, 19, 25, 30 September 2019
|
Noise Monitoring
|
4,
10, 16, 26 September 2019
|
Water Quality Monitoring
|
4,
6, 9, 11, 13, 16, 18, 20, 23, 25, 27 and 30 September 2019
|
Chinese White Dolphin Monitoring
|
4, 11, 17 and 23
September 2019
|
Site Inspection
|
4, 11, 18 and 27 September 2019
|
Mudflat
Monitoring (Mudflat)
|
9, 10, 23, 25 September
2019
|
Mudflat
Monitoring (Sedimentation Rate)
|
12 September 2019
|
As Strong Wind Signal, No.
3 /Standby Signal No.1 was hoisted on 2 September 2019. The water quality
monitoring for both ebb and flood tides on 2 September 2019 were cancelled due
to safety reason and no substitute monitoring was conducted.
Due to boat unavailability
on 16, 25 September 2019, the dolphin monitoring on 16 September 2019 was
rescheduled to 17 September 2019; and the dolphin monitoring on 25 September
2019 was rescheduled to 23 September 2019.
Due to weather condition
and manpower allocation, the mudflat monitoring on 11, 12, 13 September 2019
were rescheduled to 10, 23, 25 September 2019.
Breaches of Action and Limit Levels
A summary of environmental
exceedances for this reporting month is as follows:
Environmental Monitoring
|
Parameters
|
Action Level (AL)
|
Limit Level (LL)
|
Air Quality
|
1-hr TSP
|
0
|
0
|
24-hr TSP
|
0
|
0
|
Noise
|
Leq (30 min)
|
0
|
0
|
Water Quality
|
Suspended solids level (SS)
|
2
|
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.
The works area WA5
was handed over to other party on 22 June 2013.
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.
Original WQM stations IS8 and SR4(N) are located
within the active work area of TCNTE project and the access to the WQM stations
IS8 (Coordinate: E814251, N818412) and SR4(N) (Coordinate: E814705, N817859)
are blocked by the silt curtains of the Tung Chung New Town Extension (TCNTE)
project. Alternative monitoring stations IS8(N) (Coordinate: E814413, N818570)
and SR4(N2) (Coordinate: E814688, N817996) are proposed to replace the original
monitoring stations IS8 and SR4(N). Proposal for permanently relocating the aforementioned stations was approved by EPD on 20 August
2019. The water quality monitoring has been
conducted at stations IS8(N) and SR4(N2) on 21 August 2019.
There were no marine works conducted by
Contract No. HY/2011/03 since July 2019. A proposal for temporary suspension of
marine related environmental monitoring (water quality monitoring and dolphin
monitoring for the Contract No. HY/2011/03) was justified by the ET leader and
verified by IEC in mid of September 2019 and it was approved by EPD on 24
September 2019. Water quality monitoring and dolphin monitoring for the
Contract will not be conducted starting from 1 October 2019 until marine works
(i.e. toe loading removal works) be resumed. As discussed with Contract No. HY/2012/08,
they will take up the survey works staring from 1 October 2019 and continue the
dolphin monitoring.
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 Landscaping works at Portion X and Airport Road;
ˇP E&M works at Portion X and Airport Road;
ˇP Works for Diversion of Airport Road;
ˇP
Establishment of Site
Access at Airport Road / Airport Express Line/ East Coast Road;
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 eighty-fourth Monthly EM&A report for the Contract which summarizes the
monitoring results and audit findings of the EM&A programme
during the reporting period from 1 to 30 September 2019.
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)
|
Jackson Wong
|
3968 4802
|
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
|
Ray Yan
|
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
|
Loading
and unloading of fill materials
|
Portion X
|
Landscaping
works
|
Portion X and Airport
Road
|
Works for diversion
|
Airport Road
|
Establishment of Site Access
|
Airport Road / Airport Express Line/ East Coast Road
|
E&M works
|
Airport Road
|
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 Indicator (Model No. LD-5R)
|
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 September 2019
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
|
35
|
8 - 67
|
352
|
500
|
AMS6
|
35
|
11 - 84
|
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
|
62
|
22 - 113
|
164
|
260
|
AMS6
|
58
|
20 - 114
|
173
|
260
|
2.7.2 No Action and Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at stations
AMS5 and AMS6 during the reporting month. The event action plan is annexed in Appendix F.
2.7.3 On-site
wind meter was irreparably damaged and the wind data could not be retrieved
since August 2019. As the wind data
could not be monitored, the wind data during this reporting month were
reference to the wind data obtained from Hong Kong Observatoryˇ¦s Chek Lap Kok weather station. The
wind data obtained from Chek Lap Kok
weather station are 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 September 2019 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
|
60
|
57 ˇV 62
|
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
Major noise sources during the noise monitoring
included aircraft/helicopter noise and nearby construction activities by other
parties.
3.7.4
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(N), IS(Mf)9 & IS10(N)
Control/Far Field
Stations:
CS2(A) & CS(Mf)5,
Sensitive Receiver
Stations:
SR3(N), SR4(N2), SR5(N), SR10A(N) & SR10B(N2)
|
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).
|
Remark:
1) Original WQM stations IS8 and SR4(N) are located within the active work
area of TCNTE project and the access to the WQM stations IS8 (Coordinate:
E814251, N818412) and SR4(N) (Coordinate: E814705, N817859) are blocked by the
silt curtains of the Tung Chung New Town Extension (TCNTE) project. Alternative
monitoring stations IS8(N) (Coordinate: E814413, N818570) and SR4(N2)
(Coordinate: E814688, N817996) were proposed to replace the original monitoring
stations IS8 and SR4(N). Proposal for permanently relocating the aforementioned
stations was approved by EPD on 20 August 2019. The water quality monitoring
has been conducted at stations IS8(N) and SR4(N2) since 21 August 2019.
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(N) (Coordinate:
810525E, 816456N), SR4(N) (Coordinate: 814760E, 817867N), SR10A(N) (Coordinate:
823741E, 823495N) and SR10B(N2) (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 Original WQM stations IS8 and
SR4(N) are located within the active work area of TCNTE project and the access
to the WQM stations IS8 (Coordinate: E814251, N818412) and SR4(N) (Coordinate:
E814705, N817859) are blocked by the silt curtains of the Tung Chung New Town
Extension (TCNTE) project. Alternative monitoring stations IS8(N) (Coordinate:
E814413, N818570) and SR4(N2) (Coordinate: E814688, N817996) were proposed to
replace the original monitoring stations IS8 and SR4(N). Proposal for
permanently relocating the aforementioned stations was approved by EPD on 20
August 2019. The water quality monitoring has been conducted at stations IS8(N)
and SR4(N2) since 21 August 2019.
4.4.5
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(N)
|
Impact Station (Close to
HKBCF construction site)
|
814413
|
818570
|
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(N2)
|
Sensitive receivers (Tai
Ho Inlet)
|
814688
|
817996
|
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
|
|
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 September 2019 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 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. No
Limit Level exceedances of suspended solid level were recorded during the reporting month.
4.7.4
On
30 September 2019, an Action Level exceedance of suspended solid was recorded
at station IS10(N) during mid-ebb tide and an Action Level exceedance of
suspended solid was recorded at station SR5(N) during mid-flood tide.
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(N)
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS(Mf)9
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
IS10(N)
|
Action Level
|
30 Sep 2019
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
1
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
SR3(N)
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
SR4(N2)
|
Action Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
Limit Level
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
0
|
SR5(N)
|
Action Level
|
--
|
30 Sep 2019
|
--
|
--
|
--
|
--
|
--
|
--
|
0
|
1
|
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
|
0
|
2**
|
Limit
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0**
|
Notes:
S: Surface;
M: Mid-depth;
** The
total number of
exceedances
4.7.6 Land-based work including
landscaping works at Zone 1 and Zone 3 were carried out on 30 September 2019. No wastewater was discharged from work areas of this
Contract to the open water on 30 September 2019. It is also noted that
exceedances were not recorded at stations IS5, IS(Mf)6 and IS7 which are located close to the site boundary of this
Contract. As confirmed by the Contractor of this Contract, there were no
marine based works and no marine transportation in the vicinity of stations
IS10(N) and SR5(N) which are located far away the site boundary of this
Contract (over 1.5 km).
4.7.7 Water appearance was observed
clear at stations IS10(N) and SR5(N) during sampling exercise. No silt plume was observed in the vicinity of stations IS10(N)
and SR5(N) during the sampling exercise. Also, no abnormity or malpractice
for the contract works was observed during the sampling exercise
4.7.8 There were no specific activities recorded during the monitoring period that
would cause any significant impacts on the monitoring results. As such,
the exceedances of suspended solid level are 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.
4.7.9
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.
Vessel-based Line-transect Survey
5.3.1
During the month
of September 2019, two sets of systematic line-transect vessel surveys were
conducted on the 4th, 11th, 17th and 23rd 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 267.91
km of survey effort was collected
with 98.8% 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, 99.40
km and 168.51
km of survey effort were collected from
NEL and NWL survey areas respectively. Moreover,
the total survey effort conducted on primary lines was
193.93 km, while the effort on secondary lines was
73.98
km.
5.3.4
During the two sets of
monitoring surveys in September 2019, two
groups of five Chinese White Dolphins were sighted
(Annex II of Appendix H). Both
dolphin sightings were made in NWL, while none was sighted in NEL.
5.3.5
Notably, one of the two dolphin groups was
sighted on primary line during on-effort search. Both dolphin groups were not associated
with any operating fishing vessel (Annex
II of Appendix H).
5.3.6
Distribution of the dolphin sightings made
in September 2019 is shown in Figure 6
of Appendix H. The two
dolphin groups were sighted near Black Point and to the west of Sha Chau
respectively (Figure 6 of Appendix H).
5.3.7
During the Septemberˇ¦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.
5.3.8
The average dolphin group size in September
2019 was 2.5 individuals per group (with two groups of five animals in total),
which was slightly lower than the averages in previous monitoring months. Both
groups were quite small with two and three animals only respectively (Annex II of Appendix H).
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: September 4th / 11th
|
0.0
|
0.0
|
Set
2: September 17th / 23rd
|
0.0
|
0.0
|
NWL
|
Set
1: September 4th / 11th
|
1.6
|
3.3
|
Set
2: September 17th / 23rd
|
0.0
|
0.0
|
Remark:
1. Dolphin Encounter Rates Deduced from the Two
Sets of Surveys in September 2019 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
|
3.0
|
Remark:
1.
Overall dolphin encounter rates (sightings per 100 km of survey
effort) from the surveys conducted in September 2019 on primary lines only as
well as both primary lines and secondary lines in Northeast and Northwest
Lantau).
Photo-identification Work
5.3.9
Only three of the five dolphins sighted
during the monitoring month were identified as known individual dolphin from
the photo-identification catalogue (Annexes
III and IV of Appendix H). Two of
them (NL202 and NL286) were a mother-calf pair that have been sighted many
times in previous monitoring surveys throughout the HKLR03 construction period.
Conclusion
5.3.10
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.
5.4.1 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.
Methodology
6.1.1 To avoid disturbance
to the mudflat and nuisance to navigation, no fixed marker/monitoring rod was
installed at the monitoring stations. A high precision Global Navigation
Satellite System (GNSS) real time location fixing system (or equivalent
technology) was used to locate the station in the precision of 1mm, which is
reasonable under flat mudflat topography with uneven mudflat surface only at
micro level. This method has been
used on Agricultural Fisheries and Conservation Departmentˇ¦s (AFCD) project,
namely Baseline Ecological Monitoring Programme for the Mai Po Inner Deep Bay
Ramsar Site for measurement of seabed levels.
6.1.2 Measurements were
taken directly on the mudflat surface. The Real Time Kinematic GNSS (RTK GNSS)
surveying technology was used to measure mudflat surface levels and 3D
coordinates of a survey point. The
RTK GNSS survey was calibrated against a reference station in the field before
and after each survey. The
reference station is a survey control point established by the Lands Department
of the HKSAR Government or traditional land surveying methods using
professional surveying instruments such as total station, level and/or geodetic
GNSS. The coordinates system was in
HK1980 GRID system. For this
contract, the reference control station was surveyed and established by
traditional land surveying methods using professional surveying instruments
such as total station, level and RTK GNSS.
The accuracy was down to mm level so that the reference control station
has relatively higher accuracy. As
the reference control station has higher accuracy, it was set as true
evaluation relative to the RTK GNSS measurement. All position and height correction were
adjusted and corrected to the reference control station. Reference station survey result and
professional land surveying calibration is shown as Table 6.1:
Table 6.1 Reference
Station Survey result and GNSS RTK calibration result of Round 1
Reference Station
|
Easting (m)
|
Northing (m)
|
Baseline reference elevation (mPD) (A)
|
Round 1 Survey (mPD) (B)
|
Calibration Adjustment (B-A)
|
T1
|
811248.660mE
|
816393.173mN
|
3.840
|
3.817
|
-0.023
|
T2
|
810806.297mE
|
815691.822mN
|
4.625
|
4.653
|
+0.028
|
T3
|
810778.098mE
|
815689.918mN
|
4.651
|
4.660
|
+0.009
|
T4
|
810274.783mE
|
816689.068mN
|
2.637
|
2.709
|
+0.072
|
6.1.3 The precision of the
measured mudflat surface level reading (vertical precision setting) was within
10 mm (standard deviation) after averaging the valid survey records of the XYZ
HK1980 GRID coordinates. Each survey
record at each station was computed by averaging at least three measurements
that are within the above specified precision setting. Both digital data
logging and written records were collected in the field. Field data on station fixing and mudflat
surface measurement were recorded.
Monitoring Locations
6.1.4 Four monitoring
stations were established based on the site conditions for the sedimentation
monitoring and are shown in Figure
6.1.
Monitoring Results
6.1.5 The baseline
sedimentation rate monitoring was in September 2012 and impact sedimentation
rate monitoring was undertaken on 12
September 2019. The mudflat surface levels at the four
established monitoring stations and the corresponding XYZ HK1980 GRID
coordinates are presented in Table 6.2
and Table 6.3.
Table 6.2 Measured Mudflat
Surface Level Results
|
Baseline Monitoring
(September 2012)
|
Impact Monitoring
(September 2019)
|
Monitoring
Station
|
Easting
(m)
|
Northing
(m)
|
Surface
Level
(mPD)
|
Easting
(m)
|
Northing
(m)
|
Surface
Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.144
|
816678.726
|
1.118
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.295
|
815831.522
|
0.970
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.578
|
815953.313
|
1.486
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.460
|
816151.363
|
1.139
|
Table 6.3 Comparison
of measurement
|
Comparison of measurement
|
Remarks
and Recommendation
|
Monitoring Station
|
Easting (m)
|
Northing (m)
|
Surface Level
(mPD)
|
S1
|
-0.016
|
-0.001
|
0.168
|
Level continuously increased
|
S2
|
0.023
|
-0.009
|
0.106
|
Level continuously increased
|
S3
|
-0.007
|
0.005
|
0.145
|
Level continuously increased
|
S4
|
0.027
|
-0.018
|
0.208
|
Level continuously increased
|
6.1.6 This measurement result was
generally and relatively higher than the baseline measurement at S1, S2, S3 and
S4. The mudflat level is continuously increased.
6.2.1 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.
6.2.2 Impact water quality
monitoring in San Tau (monitoring station SR3(N)) was conducted in September
2019. The monitoring parameters included dissolved oxygen (DO), turbidity and
suspended solids (SS).
6.2.3 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)
|
02-Sep-2019
|
(See remark 1)
|
(See remark 1)
|
(See remark 1)
|
(See remark 1)
|
(See remark 1)
|
(See remark 1)
|
04-Sep-2019
|
5.9
|
7.4
|
8.0
|
6.3
|
7.2
|
7.8
|
06-Sep-2019
|
5.4
|
1.5
|
3.7
|
6.4
|
5.5
|
9.7
|
09-Sep-2019
|
10.4
|
2.5
|
4.5
|
6.5
|
4.3
|
9.8
|
11-Sep-2019
|
8.1
|
5.5
|
4.5
|
6.1
|
1.5
|
3.9
|
13-Sep-2019
|
6.9
|
7.4
|
3.7
|
5.9
|
1.8
|
1.9
|
16-Sep-2019
|
5.4
|
10.2
|
9.5
|
5.9
|
8.4
|
9.2
|
18-Sep-2019
|
5.0
|
7.1
|
9.3
|
5.9
|
9.5
|
8.2
|
20-Sep-2019
|
5.7
|
5.8
|
12.7
|
6.0
|
5.4
|
11.9
|
23-Sep-2019
|
5.8
|
2.5
|
6.3
|
6.2
|
3.5
|
5.2
|
25-Sep-2019
|
6.7
|
9.2
|
5.9
|
6.3
|
15.5
|
19.6
|
27-Sep-2019
|
6.4
|
6.3
|
10.0
|
6.0
|
4.1
|
6.0
|
30-Sep-2019
|
5.9
|
2.3
|
9.0
|
6.0
|
2.4
|
6.7
|
Average
|
6.5
|
5.6
|
7.2
|
6.1
|
5.7
|
8.3
|
|
Sampling Zone
6.3.1
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
2019 (totally 4 sampling days on 9th,
10th, 23th and 25th September 2019).
6.3.2
Since the field survey of June
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 Way. Respective measures (e.g. manual clean-up) should be
implemented by responsible governmental agency units.
Horseshoe Crabs
6.3.3
Active search method was adopted 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 hour 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 9th,
10th, 23th and 25th September 2019, which were hot and humid days.
6.3.4
In June 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 units.
Seagrass Beds
6.3.5
Active search method was adopted 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 9th (for ST), 10th (for TC2),
23th (for TC1) and 25th (for TC3) September 2019 which were hot and humid days.
Intertidal Soft Shore Communities
6.3.6 The intertidal soft shore community
surveys were conducted in low tide period on 9th (for ST), 10th (for TC2),
23th (for TC1) and 25th (for TC3) September 2019. In every sampling zone, three
100m horizontal transect lines were laid at high tidal level (H: 2.0m above
C.D.), mid tidal level (M: 1.5m above C.D.) and low tidal level (L: 1.0m above
C.D.). Along every horizontal transect line; ten random quadrats (0.5 m x 0.5m)
were placed.
6.3.7 Inside a quadrat, any visible epifauna was collected and was 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 was collected
and identified. Finally, the top 5 cm surface sediment was dug for visible
infauna in the quadrat regardless of hand core sample was taken.
6.3.8 All collected fauna were released after recording except some tiny
individuals that were too small to be identified on site. These tiny
individuals were taken to laboratory for identification under dissecting
microscope.
6.3.9 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
6.3.10 Data collected from
direct counting 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.
6.4.1 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
6.5.1
In total of 42 and 8 individuals of Carcinoscorpius rotundicauda
and Tachypleus tridentatus were
found in present survey. The
recorded individuals were mainly distributed along the shoreline from TC3 to
ST. All of them were observed on similar substratum (fine sand or soft mud,
slightly submerged). Photo records of the observed horseshoe crab are shown in Figure 3.1 of Appendix I and the present survey result regarding
horseshoe crab are presented in Table 3.1 of
Appendix I. The
complete survey records are presented in
Annex II of Appendix I.
6.5.2
For Carcinoscorpius rotundicauda, more
individuals (32 ind.) were found in TC3 with average body size 37.02mm
(prosomal width ranged 10.13 ˇV 70.71mm).
In ST, there were 9 individuals with average body size 26.81mm (prosomal width
ranged 18.25 ˇV 35.41mm). In TC2, only 1 individual
with body size 20.32mm was found in present survey. The research record in TC3
was medium (5.33 ind. hr-1 person-1), while that in ST
was low (1.50 ind. hr-1 person-1). In TC2, the research
record was very low (0.25 ind. hr-1 person-1). No individual of horseshoe crab, Carcinoscorpius rotundicauda, was recorded at TC1 in
present survey.
6.5.3
For Tachypleus tridentatus,
8 individuals with average body size 47.62mm (prosomal width ranged 20.52 ˇV 98.14mm) were found in TC3. The research
record in TC3 was low (1.33 ind. hr-1. Person-1), No Tachypleus
tridentatus were found in TC1, TC2 and ST in
present survey.
6.5.4
No mating pair or large individual
(≥100mm) was found in present survey.
6.5.5
In the survey of March 2015, there was one important finding that a mating
pair of Carcinoscorpius rotundicauda
was found in ST (prosomal width: male 155.1mm, female 138.2mm). It indicated
the importance of ST as a breeding ground of horseshoe crab. In June 2017,
mating pairs of Carcinoscorpius rotundicauda were 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 December 2017 and June 2018, one mating pair was of Carcinoscorpius rotundicauda
was found in TC3 (December 2017: male 127.80 mm, female 144.61 mm; June 2018: male
139 mm, female 149 mm). In June 2019, one pair of Tachypleus
tridentatus with large body sizes (male
150mm and Female 200mm; Male 180mm and Female 220mm) was found. Another mating pair was found
in ST (male 140mm and Female 180mm). (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 (March ˇV September) because
tiny individuals (i.e. newly hatched) were usually recorded in June and September
every year (Figure 3.3 of Appendix I).
6.5.6
Despite of mating pair, there were occasional records of large
individuals of Carcinoscorpius rotundicauda (prosomal width ranged 114.45
ˇV 178.67 mm, either single or in pair) and Tachypleus tridentatus
(prosomal width 103 mm) (Figure 3.4 of Appendix I). In December 2018, one large individual of Carcinoscorpius
rotundicauda was found in TC3 (prosomal width
148.9 mm). In March 2019, 3 large individuals (prosomal width ranged 220
ˇV 310mm) of Carcinoscorpius rotundicauda were observed in TC2. In June 2019, there
were 3 and 7 large individuals of Tachypleus
tridentatus were recorded in ST (prosomal width ranged
140 ˇV 180mm) and TC3 (prosomal
width ranged 150 ˇV 220mm), respectively. Based
on their sizes, it indicated that individuals of prosomal width larger than 100
mm would progress its nursery stage from intertidal habitat to sub-tidal
habitat of Tung Chung Wan. These large individuals might move onto intertidal
shore occasionally during high tide for foraging and breeding. Because they
should be inhabiting sub-tidal habitat most of the time. Their records were
excluded from the data analysis to avoid mixing up with juvenile population
living on intertidal habitat.
6.5.7
No marked individual of horseshoe crab was recorded in
the present survey. Some marked individuals were found in the previous surveys
of September 2013, March 2014 and September 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 crabs population might be restored in the natural habitat. Through a
personal conversation with Prof. Shin, about 100 individuals were released in
the sampling zone ST on 20 June 2013. All of them were marked with color tape
and internal chip detected by specific chip sensor. There should be second
round of release between June and September 2014 since new marked individuals
were found in the survey of September 2014
6.5.8
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
6.5.9 Figure 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 in respectively in each sampling zone
throughout the monitoring period.
6.5.10 To consider the entire monitoring
period for TC3 and ST, medium to high search records (i.e. number of
individuals) of both species (Carcinoscorpius rotundicauda and Tachypleus tridentatus)
were usually found in wet season (June and September). The search record of ST
was higher from September 2012 to June 2014 while it was replaced by TC3 from
September 2014 to June 2015. The search records were similar between two
sampling zones from September 2015 to June 2016. In September 2016, the search
record of Carcinoscorpius rotundicauda
in ST was much higher than TC3. From March to June 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 September 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 September. One possible reason was that
the serial cyclone hit decreased horseshoe crab activity (totally 4 cyclone
records between June and September 2017, to be discussed in 'Seagrass survey'
section). From December 2017 to
September 2018, the search records of both species increased again to
low-moderate level in ST. Relatively higher population fluctuation of Tachypleus tridentatus
was observed in TC3.
6.5.11 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. There were occasional records of 1 to 4 individuals
between March and September throughout the monitoring period. The maximum
record was 6 individuals only in June 2016.
6.5.12
About the body size, larger individuals of Carcinoscorpius rotundicauda were
usually found in ST and TC1 relative to that in TC3 from September 2012 to June
2017. But the body size was higher in TC3 and ST followed by TC1 from September
2017 to March 2019. For Tachypleus tridentatus,
larger individuals were usually found in ST and TC3 followed by TC1 throughout
the monitoring period. In June 2019, all found horseshoe crabs were large
individuals and mating pairs. In September 2019 (present survey), the sizes of
the horseshoe crabs were decrease. It is believed that the size of horseshoe
crabs would be gradually rise afterward due to the stable growth of juveniles
after the spawning season.
6.5.13
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 substratum. 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
6.5.14 Throughout
the monitoring period, the search records of horseshoe crabs were fluctuated
and at moderate ˇV very low level in June (Figures
3.5 and 3.6 of Appendix I). Low ˇV Very low
search record was found in June 2013, totally 82 individuals of Tachypleus tridentatus
and 0 ind. of Carcinoscorpius rotundicauda were
found in TC1, TC3 and ST. Compare with the search record of June 2013, the
numbers of Tachypleus tridentatus
were gradually decreased in June 2014 and 2015 (55 ind. in 2014 and 18 ind. in
2015); the number of Carcinoscorpius
rotundicauda raise to 88 and 66 individuals. in
June 2014 and 2015 respectively. In June 2016, the search record increased
about 3 times compare with June 2015. In total, 182 individuals of Carcinoscorpius rotundicauda
and 47 individuals. of Tachypleus tridentatus
were noted, respectively. Then, the search record was similar to June 2016. The
number of recorded Carcinoscorpius rotundicauda(133
ind.) slightly dropped in June 2017. However, that of Tachypleus tridentatus rapidly increased (125
ind.). In June 2018, the search record was low to moderate while the numbers of
Tachypleus tridentatus
dropped sharply (39 ind.). In March 2019, 3 individuals of Carcinoscorpius rotundicauda
were observed in TC2. However, all of them were large individuals (prosomal
width >100mm), their records are excluded from the data analysis to avoid
mixing up with the juvenile population living on intertidal habitat. Throughout
the monitoring period, similar distribution of horseshoe crabs population were
found in March. Most of the horseshoe crabs were found in TC3 and ST.
6.5.15 The search record of horseshoe crab declined
obviously in all sampling zones during dry season especially December (Figures 3.5 and 3.6 of Appendix I) throughout the monitoring period. Very low ˇV low
search record was found in December from 2012 to 2015 (0-4 ind. of Carcinoscorpius rotundicauda
and 0-12 ind. of Tachypleus tridentatus). 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-1person-1 and 0.00 ind. hr-1
person-1 in wet season and dry season respectively (details see Li,
2008). Compare with the search record of December from 2012 to 2015, which of
December 2016 were much higher relatively. There were totally 70 individuals of
Carcinoscorpius rotundicauda
and 24 individuals of Tachypleus tridentatus in TC3 and ST. Since the survey was carried
in earlier December with warm and sunny weather (~22 ºC during dawn according
to Hong Kong Observatory database, Chek Lap Kok station on 5 December 2016), the horseshoe crab was
more active (i.e. move onto intertidal shore during high tide for foraging and
breeding) and easier to be found. In contrast, there was no search record in
TC1 and TC2 because the survey was conducted in mid-December with colder and
cloudy weather (~20 ºC during dawn on 19 December). The horseshoe
crab activity would decrease gradually with the colder climate. In December of
2017 and 2018, very low search records were found again as mentioned above.
6.5.16 From September 2012 to December
2013, Carcinoscorpius rotundicauda
was less common species relative to Tachypleus tridentatus. Only 4 individuals were ever recorded in
ST in December 2012. This species had ever been believed of very low density in
ST hence the encounter rate was very low. In March 2014, it was found in all
sampling zones with higher abundance in ST. Based on its average size (mean
prosomal width 39.28-49.81 mm), it indicated that breeding and spawning of this
species had occurred about 3 years ago along the coastline of Tung Chun Wan.
However, these individuals were still small while their walking trails were
inconspicuous. Hence there was no search record in previous sampling months.
Since March 2014, more individuals were recorded due to larger size and higher
activity (i.e. more conspicuous walking trail).
6.5.17 For Tachypleus tridentatus, sharp increase of number of
individuals was recorded in ST during the wet season of 2013 (from March to
September). According to a personal conversation with Prof. Shin (CityU), his monitoring team had recorded similar increase
of horseshoe crab population during wet season. It was believed that the
suitable ambient temperature increased its conspicuousness. However similar
pattern was not recorded in the following wet seasons. The number of
individuals increased in March and June 2014 and followed by a rapid decline in
September 2014. Then the number of individuals fluctuated slightly in TC3 and
ST until March 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 March 2014. Then it varied
slightly between 35-65 mm from September 2014 to March 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 June 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. In September 2017, moderate
numbers of individual were found in TC3 and ST indicating a stable population
size. In September 2018, the population size was lower while natural mortality
was the possible cause.
6.5.18 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 in 2018, the number of Tachypleus tridentatus became increased TC3 and ST.
Since TC3 and ST were regarded as important nursery ground for both horseshoe
crab species, box plots of prosomal width of two horseshoe crab species were
constructed to investigate the changes of population in details.
Box plot of horseshoe crab populations in TC3
6.5.19
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 September
2012 and December 2013 hence the data were lacking. In March 2014, the major
size (50% of individual records between upper (top box) and lower quartile (bottom
box)) ranged 40 ˇV 60 mm while only few individuals were found.
From March 2014 to September 2018, the median prosomal width (middle line of
whole box) and major size (whole box) decreased after March of every year. It
was due to more small individuals found in June indicating new rounds of
spawning. Also, there were slight increasing trends of body size from June to
March 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
ˇV 90 mm) along the sampling months. Juveniles
reaching this size might gradually migrate to sub-tidal habitats.
6.5.20 For Tachypleus tridentatus,
the major size ranged 20-50 mm while the number of individuals fluctuated from
September 2012 to June 2014. Then a slight but consistent growing trend was
observed from September 2014 to June 2015. The prosomal width increased from 25
ˇV 35 mm to 35
ˇV 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 March to September 2016, slight increasing trend of
major size was noticed again. From December 2016 to June 2017, similar increasing
trend of major size was noted with much higher number of individuals. It
reflected new round of spawning. In September 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 June and September 2017 (to be
discussed in the 'Seagrass survey' section). From December 2017 to September
2018, increasing trend was noted again. Across the whole monitoring period, the
larger juveniles (upper whisker) usually reached 60 ˇV 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
6.5.21
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 September 2012
and December 2013 hence the data were lacking. From March 2014 to September 2018,
the size of major population decreased and more small individuals (i.e. lower
whisker) were recorded after June of every year. It indicated new round of
spawning. Also, there were similar increasing trends of body size from
September to June of next year between 2014 and 2017. It indicated a stable
growth of individuals. The larger juveniles (i.e. upper whisker usually ranged 60 ˇV 80 mm in prosomal width except one individual
(prosomal width 107.04 mm) found in March 2017. It reflected juveniles reaching
this size would gradually migrate to sub-tidal habitats.
6.5.22
For Tachypleus tridentatus,
a consistent growing trend was observed for the major population from December
2012 to December 2014 regardless of change of search record. The prosomal width
increased from 15-30 mm to 60 ˇV 70 mm. As mentioned, the large
juveniles might have reached a suitable size for migrating from the nursery
soft shore to subtidal habitat. From March to September 2015, the size of major
population decreased slightly to a prosomal width 40 ˇV 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 December 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 March 2016, the number of
individual was very few in ST that no box plot could be produced. In June 2016,
the prosomal width of major population ranged 50 ˇV 70 mm. But it dropped clearly to
30 ˇV 40 mm in September 2016 followed by an increase to 40 ˇV 50 mm in December 2016, 40 ˇV 70 mm in March 2017 and 50 ˇV 60mm in June 2017. Based on
overall higher number of small individuals from June 2016 to September 2017, it
indicated another round of spawning. From September 2017 to June 2018, the
major size range increased slightly from 40 ˇV 50 mm to 45 ˇV 60 mm indicating a continuous
growth. In September 2018, decrease of major size was noted again that might
reflect new round of spawning. Throughout the monitoring period, the larger
juveniles ranged 60ˇV 80 mm in prosomal width. Juveniles reaching this size would gradually
migrate to sub-tidal habitats.
6.5.23 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. The population
size was consistent 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 the population size increased to a moderate level.
6.5.24 In
March to June 2019, no horseshoe
crab juveniles (prosomal width
<100mm) were recorded in TC3 and ST. All recorded horseshoe crabs were large individuals (prosomal width
>100mm) or mating pairs which were all excluded from the data analysis. In September 2019, the population
size of both horseshoe crab species in TC3 and ST gradually increased to low
ˇV moderate
level while their body sizes were mostly in small to medium range (~30
ˇV 50mm).
Impact of the HKLR project
6.5.25
It was the 28th survey of the
EM&A programme during construction period. Based
on the monitoring results, no detectable impact on horseshoe crab was revealed
due to HKLR project. The population change was mainly determined by seasonal
variation, no abnormal phenomenon of horseshoe crab individual, such as large
number of dead individuals on the shore) had been reported.
Seagrass Beds
6.5.26 Only
seagrass species Halophila ovalis was found in present survey, which was found in
TC3 and ST. In ST, There were
one small sized and one large
sized of seagrass beds found at tidal
zone 1.5 ˇV 2.0 m above C.D nearby mangroves plantation. The larger rand had area ~1000 m2 in
high vegetation coverage (90 ˇV 100%). At close vicinity, a small sized (~200 m2)
of Halophila ovalis beds in low vegetation coverage (10-20%) were observed at tidal zone 1.5 ˇV 2.0 m
above C.D. In TC3, four
small patches of Halophila ovalis were found at tidal zone 1.5 ˇV 2.0m above C.D. These seagrass pataches
had areas ~0.25 ˇV 9 m2 in high
vegetation coverage (90 ˇV 100%). Another seagrass species Zostera
japonica was not
found in present survey. Table 3.2 of Appendix I summarizes the results of
present seagrass beds survey and the photograph records of the seagrass are
shown on Figure 3.9 of Appendix I. The
complete record throughout the monitoring period is presented in Annex III of Appendix I.
6.5.27 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 3.10
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 ˇV 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 co-existed with Halophila ovalis nearby
the mangrove strand at 2.0 m above C.D.
6.5.28 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
6.5.29 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 Mach 2013 that grew within the large patch of seagrass Halophila
ovalis. Then, the patch size increased and merged gradually with the warmer
climate from March to June 2013 (15 m2). However, the patch size
decreased and remained similar from September 2013 (4 m2) to March 2014 (3 m2).
In June 2014, the patch size increased obviously again (41 m2) with
warmer climate followed by a decrease between September 2014 (2 m2)
and December 2014 (5 m2). From March to June 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 September 2015 to June
2016, it was found coexisting with seagrass Halophila ovalis with steady
increasing patch size (from 44 m2 to 115 m2) and variable coverage.
In September 2016, the patch size decreased again to (38 m2)
followed by an increase to a horizontal strand (105.4 m2) in June
2017. And it did no longer co-exist with Halophila ovalis. Between
September 2014 and June 2017, an increasing trend was noticed from September to
June of next year followed by a rapid decline in September of next year. It was
possibly the causes of heat stress, typhoon and stronger grazing pressure
during wet season. However, such increasing trend was not found from September
2017 to September 2019 (present survey) while no patch of Zostera
japonica was found.
6.5.30 For Halophila ovalis, it was recorded
as 3 ˇV 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
September 2012. The total seagrass bed area grew steadily from 332.3 m2
in September 2012 to 727.4 m2 in December 2013. Flowers were
observed in the largest patch during its flowering period. In March 2014, 31
small to medium patches were newly recorded (variable area 1 ˇV 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 June 2014,
these small and medium patches grew and extended to each other. These patches
were no longer distinguishable and were covering a significant mudflat area of
ST. It was generally grouped into 4 large patches (1116 - 2443 m2)
of seagrass beds characterized of patchy distribution, variable vegetable
coverage (40 - 80%) and smaller leaves. The total seagrass bed area increased
sharply to 7629 m2. In September 2014, the total seagrass area
declined sharply to 1111m2. 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 September 2014, there were two tropical cyclone records
in Hong Kong (7th-8th September: no cyclone name, maximum
signal number 1; 14th - 17th September: Kalmaegi, maximum signal number 8SE) before the seagrass
survey dated 21stSeptember 2014. The strong water current caused by the
cyclone, Kalmaegi especially, might have given damage
to the seagrass beds. In addition, natural heat stress and grazing force were
other possible causes reducing seagrass beds area. Besides, very small patches
of Halophila ovalis could be found in other mud flat area in addition to
the recorded patches. But it was hardly distinguished due to very low coverage
(10 - 20%) and small leaves.
6.5.31 In
December 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 June 2014 and December 2014.Such rapid
loss would not be seasonal phenomenon because the seagrass beds at higher tidal
level (2.0 m above C.D.) were present and normal in December 2012 and 2013.
According to Fong (1998), similar incident had occurred in ST in the past. The
original seagrass area had declined significantly during the commencement of
the construction and reclamation works for the international airport at Chek Lap Kok in 1992. The
seagrass almost disappeared in 1995 and recovered gradually after the
completion of reclamation works. Moreover, incident of rapid loss of seagrass
area was also recorded in another intertidal mudflat in Lai Chi Wo in 1998 with
unknown reason. Hence, Halophila ovalis
was regarded as a short-lived and r-strategy seagrass that could colonize areas
in short period but disappears quickly under unfavourable
conditions (Fong, 1998).
Unfavourable conditions to seagrass Halophila
ovalis
6.5.32 Typhoon or strong water current was suggested as one unfavorable
condition to Halophila ovalis (Fong,
1998). As mentioned above, there were two tropical cyclone records in Hong Kong
in September 2014. The strong water current caused by the cyclones might have
given damage to the seagrass beds.
6.5.33
Prolonged
light deprivation due to turbid water would be another unfavorable condition.
Previous studies reported that Halophila ovalis had little tolerance to
light deprivation. During experimental darkness, seagrass biomass declined
rapidly after 3-6 days and seagrass died completely after 30 days. The rapid
death might be due to shortage of available carbohydrate under limited
photosynthesis or accumulation of phytotoxic end products of anaerobic
respiration (details see Longstaff et al., 1999). Hence the seagrass bed
of this species was susceptible to temporary light deprivation events such as
flooding river runoff (Longstaff and Dennison, 1999).
6.5.34
In order to investigate any deterioration of
water quality (e.g. more turbid) in ST, the water quality measurement results
at two closest monitoring stations SR3 and IS5 of the EM&A programme were obtained from the water quality monitoring
team. Based on the results from June to December 2014, the overall water
quality was in normal fluctuation except there was one exceedance of suspended
solids (SS) at both stations in September. On 10th September 2014,
the SS concentrations measured 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 September
2014 (daily total rainfall at the Hong Kong International Airport: 0-2.1 mm;
extracted from the climatological data of Hong Kong Observatory). The effect of
upstream runoff on water quality should be neglectable in that period.
Moreover, the exceedance of water quality was considered unlikely to be related
to the contract works of HKLR according to the 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, was carried out within silt curtain as recommended in the
EIA report. Moreover, there was no leakage of turbid water, abnormity or
malpractice recorded during water sampling. In general, the exceedance of
suspended solids concentration was considered to be attributed to other
external factors, rather than the contract works.
6.5.35
Based on the weather condition and water
quality results in ST, the co-occurrence of cyclone hit and turbid waters in
September 2014 might have combined the adverse effects on Halophila ovalis that leaded to disappearance of this short-lived
and r-strategy seagrass species. Fortunately, Halophila ovalis was a fast-growing species (Vermaat
et al., 1995). Previous studies
showed that the seagrass bed could be recovered to the original sizes in 2
months through vegetative propagation after experimental clearance (Supanwanid, 1996). Moreover it was reported to recover
rapidly in less than 20 days after dugong herbivory (Nakaoka
and Aioi, 1999).As mentioned, the disappeared
seagrass in ST in 1995 could recover gradually after the completion of
reclamation works for international airport (Fong, 1998).The seagrass beds of Halophila ovalis might recolonize in the
mudflat of ST through seed reproduction as long as there was no unfavourable condition in the coming months.
Recolonization of seagrass beds
6.5.36
Figure 3.12 of Appendix I shows the recolonization of seagrass bed in ST from December 2014
to June 2017. From March to June 2015, 2 - 3 small patches of Halophila ovalis were newly found
co-inhabiting with another seagrass species Zostera japonica. But the total patch area of Halophila ovalis was still
very low compare with previous records. The recolonization rate was low while
cold weather and insufficient sunlight were possible factors between December
2014 and March 2015. Moreover, it would need to compete with seagrass Zostera japonica for substratum and nutrient,
because Zostera japonica had extended and covered the
original seagrass bed of Halophila ovalis at certain degree. From June 2015 to
March 2016, the total seagrass area of Halophila ovalis had increased rapidly
from 6.8 m2 to 230.63 m2. It had recolonized its original
patch locations and covered its competitor Zostera japonica. In June 2016, the total seagrass area increased sharply
to 4707.3m2. Similar to the previous records of March to June 2014,
the original patch area of Halophila
ovalis increased further to a horizontally long strand. Another large
seagrass beds colonized the lower tidal zone (1.0 - 1.5 m above C.D.). In
September 2016, 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-selected seagrass. In
December 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. The total seagrass bed
decreased to 12550 m2. From March to June 2017, the seagrass bed
area remained generally stable (12438 - 17046.5 m2) but the vegetation
coverage fluctuated (20 - 50% in March 2017 to 80-100% in June 2017). The whole
recolonization process took about 2.5 years.
Second disappearance of seagrass bed
6.5.37
In September 2017, the whole
seagrass bed of Halophila ovalis
disappeared again along the shore of TC3 and ST (Figure 3.12 of Appendix I). Similar to the first disappearance of seagrass bed occurred
between September and December 2014, strong water current (e.g. cyclone) or
deteriorated water qualities (e.g. high turbidity) was the possible cause.
6.5.38
Between the survey periods of
June and September 2017, there were four tropical cyclone records in Hong Kong
(Merbok in 12 - 13th, June; 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 with highest signal 10.
6.5.39
According to the water quality
monitoring results (July to August 2017) of the two closest monitoring stations
SR3 and IS5 of the respective EM&A programme, the
overall water quality was in normal fluctuation. There was an exceedance of
suspended solids (SS) at SR3 on 12 July 2017. The SS concentration reached 24.7
mg/L during mid-ebb tide, which exceeded the Action Level (≤ 23.5 mg/L). But it
was far below the Limit Level (≤ 34.4 mg/L). Since such exceedance was slight
and temporary, its effect to seagrass bed should be minimal.
6.5.40
Overall, the disappearance of
seagrass beds in ST has believed the cause of serial cyclone hit in July and
August 2017. Based on previous findings, the seagrass beds of both species were
expected to recolonize in the mudflat as long as the vicinal water quality was
normal. The whole recolonization process (from few, small patches to extensive
strand) would be gradually lasting at least 2 years. From December 2017 to
March 2018, there was still no recolonization of few, small patches of seagrass
at the usual location (Figure 3.12 of Appendix I). It was different from the previous round (March 2015 - June
2017). Until June 2018, the new seagrass patches with small-medium size 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 September 2018. Again, it was believed that
the decrease was due to the hit of the super cyclone in September 2018 (Mangkhuton 16th September, highest signal 10).
From December 2018 to June 2019, the seagrass bed area increased from 404 m2
to 1229 m2 while the vegetation coverage is also increased.
(December 2018: 5 ˇV 85%; March 2019: 50 ˇV 100% and June 2019: 60 ˇV 100%).
Relatively, the whole recolonization process would occur slower than the
previous round (more than 2 years). In
September 2019, the seagrass bed area slightly decreased to 1200 m2 which
was in normal fluctuation.
Impact of the HKLR
project
6.5.41
It was the 28th
survey of the EM&A programme during construction
period. Throughout the monitoring period, the disappearance of seagrass beds
was believed the cause of cyclone hits rather than impact of HKLR project. The
seagrass bed was since there
had been a gradual increase in the size and number from December 2018 to June
2019 after the hit of the super cyclone in September 2018. The
seagrass bed area slightly decreased in September 2019 (present survey) which
was in normal fluctuation.
Intertidal Soft Shore Communities
Substratum
6.5.42 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¦ (H: 90%; M: 70%) were
recorded at high and mid tidal levels. Relatively higher percentages of ˇĄGravels
and Bouldersˇ¦ (50%) and ˇĄSoft
mudˇ¦ (40%) were
recorded at low tidal level.
ˇP
In TC2, high percentages of ˇĄGravels and Bouldersˇ¦ (H: 80%; M: 60%) were recorded
at high and mid tidal levels. Relatively higher percentages of ˇĄGravels and
Bouldersˇ¦ (40%) and ˇĄSoft mudˇ¦ (40%) were recorded at low tidal level.
ˇP
In TC3, higher percentage of ˇĄGravels and Bouldersˇ¦ (50%) was recorded followed
by ˇĄSandˇ¦ (30%) at high tidal level. At mid tidal level, higher percentages of
ˇĄGravels and Bouldersˇ¦ (40%) and ˇĄSandˇ¦ (40%) were recorded. At low tidal
level, the main substratum type was ˇĄGravels and Bouldersˇ¦ (70%).
ˇP
In ST, ˇĄGravels
and Bouldersˇ¦ was the main substratum type (H:90%; M: 70%) at high tidal level
and mid tidal level. At low tidal level, ˇĄGravels and Bouldersˇ¦ was the main
substratum type (40%) following by ˇĄSand ˇĄ(30%) and ˇĄSoft MudˇĄ(30%).
6.5.43 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.
Soft shore communities
6.5.44 Table 3.4 of Appendix I lists the total abundance, density
and number of taxon of every phylum in this survey. A
total of 11243 individuals
were recorded. Mollusca
was the
most abundant phylum (total abundance 10594 ind, density 353 ind. m-2, relative
abundance 94.2%). The second and third abundant phya were Arthropoda (506 ind., 17 ind. m-2, 4.5%)
and Annelida
(60 ind.,
2 ind. m-2,
0.4%) respectively. Relatively other phyla
were very low in abundances
(density <2 ind. m-2, relative abundance £0.3%).
Moreover, the
most diverse phylum was Mollusca (40 taxa)
followed by Arthropoda (9 taxa) and
Annelida
(7 taxa). There were
3 taxa recorded for Sipuncula and 1 taxon for other
phyla.
6.5.45
The taxonomic resolution and
complete list of recorded fauna are shown in Annexes IV and V of Appendix I respectively. As reported in June 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
Moreover, taxonomic revision was conducted on another snail species
while the specie name was revised:
ˇP
Batillaria bornii was revised as Clypeomorus
bifasciata
6.5.46 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 (2030 - 3412 ind.) varied among
the four sampling zones while the phyla distributions were
similar. In general, Mollusca was
the most dominant phylum (no. of individuals: 1761 - 3360
ind.;
relative abundance 86.7 ˇV 98.5%; density 235 - 448 ind. m-2).
Other phyla
were much lower in number of individuals.
Arthropoda (28 - 216
ind.; 0.8 ˇV 10.6%; 4 - 29 ind. m-2)
and Annelida (3 -28 ind.; 0.1 ˇV 1.4%;
0 - 4 ind. m-2) were common
phyla relatively. Other
phyla were very low in abundance in all sampling zones.
Dominant species in every sampling zone
6.5.47
Table 3.6 of Appendix I lists the abundant species in
every sampling zone. In the present survey, most of the listed abundant species
were of low to moderate densities (42-100 ind. m-2). Few listed
species of high or very high density (>100 ind. m-2) were
regarded as dominant species. Other listed species of lower density (<42
ind. m-2) were regarded as common species.
6.5.48
In TC1, the substratum
was mainly ˇĄGravels and Bouldersˇ¦ at high and mid tidal levels. At high tidal
level, the rock oyster Saccostrea cucullata (mean density 66 ind. m-2; relative abundance 23%),
the gastropod Batillaria zonalis (44 ind. m-2; relative abundance 15%), Monodonta
labio (43 ind. m-2; relative abundance 15%) and Batillaria multiformis
(42 ind. m-2; relative abundance 14%) were of abundant species found
at low-moderate densities. At mid tidal level, the rock oyster Saccostrea cucullata (144 ind. m-2, 33%) was of dominant
species with high density. Meanwhile, the gastropod Monodonta
labio (62 ind. m-2, 14%) and Batillaria multiformis
(59 ind. m-2, 13%) were found at moderate densities. At low tidal
level (main substratum types ˇĄGravels and Bouldersˇ¦ or ˇĄSoft mudˇ¦), the Rock oyster Saccostrea cucullata (186 ind. m-2, 29%) was dominant
at high density. The gastropod Nodilittorina
radiata (108 ind. m-2, 17%) and Monodonta
labio (99 ind. m-2, 16%) were abundant
at moderate densities.
6.5.49
In TC2, the substratum types were mainly ' Gravels and Boulders' at high tidal level. Gastropods Batillaria multiformis (73 ind. m-2, 20%) and Batillaria
zonalis (47 ind. m-2, 13%), as well as the rock oyster
Saccostrea cucullata
(60 ind. m-2,
17%) were of abundant species at low - moderate densities. At mid tidal level
(major substratum type ˇĄGravels and Bouldersˇ¦), rock oyster Saccostrea cucullata (94
ind. m-2, 23%) was of dominant species at high density. Meanwhile, gastropods Batillaria zonalis (89 ind. m-2, 22%) and Monodonta labio (66
ind. m-2, 16%) were of abundant species at low- moderate density. Substratum
types ˇĄGravels and Boulders; and ˇĄSoft mudˇ¦ were evenly distributed at low
tidal level, rock oyster Saccostrea cucullata (108
ind. m-2, 27%) and the gastropod Monodonta
labio (60 ind. m-2, 15%) were of abundant
species at high densities.
6.5.50
In TC3, the substratum types were mainly ˇĄGravels and
Bouldersˇ¦ at high tidal level. The rock oyster Saccostrea cucullata (86 ind. m-2, 28%) and Batillaria multiformis (38
ind. m-2, 12%) were of abundant species at low ˇV moderate densities.
At mid tidal level, the substratum types ˇĄGravels and Bouldersˇ¦ and ˇĄSandˇ¦ were
evenly distributed. The rock oyster Saccostrea cucullata
(43 ind.m-2, 18%) was of common species, and followed by
gastropod Monodonta labio
(24 ind. m-2, 10%) and Batillaria
multiformis (24 ind. m-2, 10%). Both
of them were at low - moderate densities. At low tidal level, the major
substratum type was ˇĄGravels and Bouldersˇ¦. There was dominated by rock oyster Saccostrea
cucullata (74 ind. m-2, 28%) and
followed by two abundant species, Balanus amphitrite
(31 ind. m-2,12%) and Lunella
granulate (28 ind. m-2, 11%), at low - moderate densities.
6.5.51
In ST, the major
substratum type was ˇĄGravels and Bouldersˇ¦ at high tidal level. At high tidal
level, gastropod Monodonta labio (61 ind. m-2, 47%) and the rock oyster
Saccostrea cucullata (47 ind. m-2, 21%)
were abundant at low ˇV moderate densities. At mid tidal level, the main substratum
type was ˇĄGravals
and Bouldersˇ¦. The rock oyster Saccostrea cucullata
(80 ind.m-2, 18%)
was abundant at high density and followed by gastropods Batillaria zonalis (73
ind. m-2, 16%) and Monodonta labio (62 ind. m-2, 13%) and at low - moderate
densities. At low tidal level (major substratum: ˇĄGravals and Bouldersˇ¦), rock oyster Saccostrea cucullata (146
ind. m-2, 30 %, attached on boulders) was dominant at high
density and followed by gastropod Monodonta labio (65
ind. m-2, 13 %) at moderate density.
6.5.52 In general, there was no
consistent zonation pattern of species distribution across all sampling zones
and tidal levels. The species distribution was determined by the type of
substratum primarily. In general, rock oyster Saccostrea cucullate (1706 ind.), gastropods Monodonta labio (861
ind.), Batillaria multiformis
(746 ind.) were the most common species on gravel and boulders substratum.
Rock oyster Saccostrea cucullata
(518 ind.), Monodonta labio (244 ind.), Batillaria multiformis (219
ind.) were the most common species on sandy substrata .
Biodiversity and abundance of soft shore communities
6.5.53 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.
6.5.54 Among the sampling zones, the mean species number was
similar (6 ˇV 13 spp. 0.25 m-2) among the four sampling zones.The mean densities of TC1 (455 ind. m-2) was
higher than ST (389 ind. m-2) followed by TC2 (384 ind. m-2)
and TC3 (271 ind. m-2). The higher densities of TC1 and ST are due to the
relatively high number of individuals in each quadrat. TC1 and TC3 were
relatively higher in Hˇ¦ (1.90 and 1.83) and followed by TC2 (1.70) and ST
(1.57). TC1, TC2 and TC3 were higher in J
(0.80) compare with that of ST (0.77) due to their higher species number and
even taxa distribution.
6.5.55 In the present survey, no clear
trend of mean species number, mean density, Hˇ¦
and J observed among the tidal level.
6.5.56 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 (December) but the mean H' and J fluctuated within a limited range.
6.5.57 From June to December 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 unfavorable change reflecting
environmental stresses. The heat stress and serial cyclone hit were believed
the causes during the wet season of 2017. From March 2018 to September 2019,
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
6.5.58 It was the 28th survey
of the EM&A programme during the construction
period. Based on the results, impacts of the HKLR project were not detected on
intertidal soft shore community. Abnormal phenomena (e.g. rapid, consistent or
non-seasonal decline of fauna densities and species number) were not recorded.
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Snails in Hong Kong Mangrove. Agriculture, Fisheries and Conservation
Department Newsletter - Hong Kong Biodiversity Issue #25, 2-11
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of Ecology & Biodiversity, The University of Hong Kong. pp 117.
6.6.3 Dai,
A.Y., Yang, S.L., 1991. Crabs of the China Seas. China Ocean Press. Beijing.
6.6.4 Dong,
Y.M., 1991. Fauna of ZheJiang Crustacea. Zhejiang
Science and Technology Publishing House. ZheJiang.
6.6.5 EPD,
1997. Technical Memorandum on Environmental Impact Assessment Process (1st edition).
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worms. Definitions and keys to the orders, families and genera. Natural History
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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
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6.6.8 Li,
H.Y., 2008. The Conservation of Horseshoe Crabs in Hong Kong. MPhil Thesis,
City University of Hong Kong, pp 277.
6.6.9 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.
6.6.10 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.
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1999. Growth of seagrass Halophila ovalis
at dugong trails compared to existing within-patch variation in a Thailand
intertidal flat. Marine Ecology Progress Series 184, 97-103.
6.6.12 Pielou, E.C., 1966. Shannonˇ¦s formula as a measure
of species diversity: its use and misuse. American Naturalist 100, 463-465.
6.6.13 Qi,
Z.Y., 2004. Seashells of China. China Ocean Press. Beijing, China.
6.6.14 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.
6.6.15 Shannon,
C.E., Weaver, W., 1963. The Mathematical Theory of Communication. Urbana:
University of Illinois Press, USA.
6.6.16 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.
6.6.17 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.
6.6.18 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.
6.6.19 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 4, 11, 18 and 27 September 2019.
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
|
30 Aug 2019
|
1.
Waste
was observed at S7.
2.
Chemical
container without drip tray was observed at S7.
3.
Waste
was observed at S7.
|
1.
The
waste was removed from S7.
2.
The chemical
container was removed from S7.
3.
The
waste was removed from S7.
|
4 Sep 2019
|
4 Sep 2019
|
1.
A
chemical drum without drip tray was observed at N4.
2.
A
stockpile of dusty material was observed on the ground at S7.
3.
Waste
was observed at LCSD Depot.
|
1.
The chemical drum was removed at N4.
2.
The
stockpile of dusty material was removed from S7.
3.
The waste
was removed from LSCD Depot.
|
11 Sep 2019
|
11 Sep 2019
|
1.
Waste
was accumulated on the ground at N4.
2.
Unused
water barriers were placed near a tree at N4.
3.
A
chemical container was observed at LCSD Depot.
|
1.
The
waste was removed from N4.
2.
The
unused water barriers were removed from N4.
3.
The
chemical container was removed from LCSD Depot.
|
18 Sep 2019
|
18 Sep 2019
|
1.
Chemical
containers were observed without drip tray at N4.
2.
Stagnant
water was observed on the ground at N4.
3.
Waste
was observed on the ground at S7.
4.
Waste
was observed on the ground at LCSD Depot.
|
1.
The
chemical containers without drip tray at N4 were removed.
2. The stagnant water was removed at N4.
3.
The
waste was removed at S7.
4.
The
waste was removed at LCSD Depot.
|
27 Sep 2019
|
27 Sep 2019
|
1.
Stagnant
water was observed at S7.
2.
Unused
chemical container without drip tray was observed S7.
3.
Waste
was observed at S15.
|
The Contractor was recommended to:
1.
remove
the stagnant water from S7.
2.
provide
drip tray for the unused chemical container at S7.
3.
remove
the waste from S15.
|
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.
|
Table 7.2 Summary of Environmental Site
Inspections (Landscape works) for the Contract works area
Date of Audit
|
Observations
|
Actions Taken by Contractor / Recommendation
|
Date of Observations Closed
|
4
Sep 2019
|
No particular environmental issue was recorded
during the site inspection.
|
Nil.
|
Nil.
|
18
Sep 2019
|
No particular environmental issue was recorded
during the site inspection.
|
Nil.
|
Nil.
|
7.1.4 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, no Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at stations AMS5 and
AMS6 during the reporting month.
7.5.2 For construction noise, no Action
and Limit Level exceedances were recorded at station NMS5 during the reporting
month.
7.5.3
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. No Limit Level exceedances of suspended
solid level were recorded during the reporting month.
7.5.4 On 30 September 2019, an Action
Level exceedance of suspended solid was recorded at station IS10(N) during
mid-ebb tide and an Action Level exceedance of suspended solid was recorded at
station SR5(N) during mid-flood tide. The exceedances of suspended solid level
recorded during the reporting month were considered to be attributed to other
external factors such as sea condition, rather than the contract works.
Therefore, the exceedances were considered as non-contract related.
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 this reporting month.
7.6.2
The details of cumulative statistics of Environmental Complaints
are provided in Appendix K.
7.6.3
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 October 2019 are summarized in Table 8.1.
Table 8.1 Construction
Activities for October 2019
Site Area
|
Description of Activities
|
Portion X and Airport
Road
|
Landscaping Works
|
Portion X and Airport
Road
|
E&M works
|
Airport Road
|
Works for Diversion
|
Airport Road / Airport
Express Line/ East Coast Road
|
Establishment of Site
Access
|
Portion X
|
Finishing works for
Highway Operation and Maintenance Area Building
|
West Portal
|
Finishing Works for
Scenic Hill Tunnel West Portal Ventilation Building
|
8.1.2
8.2.1 The tentative
schedule for environmental monitoring in October 2019 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 eighty-fourth Monthly EM&A report for the
Contract which summarizes the monitoring results and audit findings of the
EM&A programme during the reporting period from 1
to 30 September 2019.
Air Quality
9.1.2 For air quality, no Action Level
and Limit Level exceedances of 1-hr TSP and 24-hr TSP were recorded at stations
AMS5 and AMS6 during the reporting month.
Noise
9.1.3 For construction
noise, no Action and Limit Level exceedances were recorded at station NMS5
during the reporting month.
Water Quality
9.1.4
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. No Limit Level exceedances of
suspended solid level were recorded during the
reporting month.
9.1.5 On 30 September 2019, an Action
Level exceedance of suspended solid was recorded at station IS10(N) during
mid-ebb tide and an Action Level exceedance of suspended solid was recorded at
station SR5(N) during mid-flood tide. The exceedances of suspended solid level
recorded during the reporting month were considered to be attributed to other
external factors such as sea condition, rather than the contract works.
Therefore, the exceedances were considered as non-contract related.
Dolphin
9.1.6 During the Septemberˇ¦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.
Mudflat
9.1.7 This measurement result was
generally and relatively higher than the baseline measurement at S1, S2, S3 and
S4.
9.1.8 The September 2019 survey results
indicate that the impacts of the HKLR project could not be detected on
intertidal soft shore community. Based on the monitoring results, no detectable impact on horseshoe crab
was revealed due to HKLR project. The population change was mainly determined
by seasonal variation, no abnormal phenomenon of horseshoe crab individual,
such as large number of dead individuals on the shore) had been reported. Throughout the monitoring period, the
disappearance of seagrass beds was believed the cause of cyclone hits rather
than impact of HKLR project. The seagrass bed was since there had been a gradual increase in the size
and number from December 2018 to June 2019 after the hit of the super cyclone
in September 2018. The seagrass bed area slightly
decreased in September 2019 (present survey) which was in normal fluctuation.
Environmental Site Inspection and
Audit
9.1.9 Environmental site inspections
were carried out on 4, 11, 18 and 27 September 2019. 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. No notification of
summons and prosecution was received during the reporting period.