The Hong Kong-Zhuhai-Macao
Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge
at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB
Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern
waters of the Hong Kong International Airport (HKIA).
The HKLR project has been
separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and
Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract)
and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department as the
Contractor to undertake the construction works of Contract No. HY/2011/03.The main works of the Contract include
land tunnel at Scenic Hill, tunnel underneath Airport Road and Airport Express
Line, reclamation and tunnel to the east coast of the Airport Island, at-grade
road connecting to the HKBCF and highway works of the HKBCF within the Airport
Island and in the vicinity of the HKLR reclamation.The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be “Designated Projects”,
under Schedule 2 of the Environmental Impact Assessment (EIA) Ordinance (Cap
499) and Environmental Impact Assessment (EIA) Reports (Register No.
AEIAR-144/2009 and AEIAR-145/2009) were prepared for the Project.The current Environmental Permit (EP)
EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF were issued on 22 December
2014 and 11 April 2016, respectively. These documents are available through the
EIA Ordinance Register. The construction phaseof Contract was commenced on 17 October 2012.
BMT 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 theseventy-eighth Monthly EM&A report for the Contract which summarizes the monitoring
results and audit findings of the EM&A programme during the reporting
period from 1 to 31 March
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, 8, 14, 20, 26 and 29 March 2019
24-hr TSP Monitoring
Noise Monitoring
1, 7, 13, 19, 25 and 28 March 2019
4, 14, 20 and 26 March 2019
Water
Quality Monitoring
1, 4, 6, 8, 11,
13, 15, 18, 20, 22, 25, 27 and 29 March 2019
Chinese White Dolphin Monitoring
Mudflat Monitoring (Ecology)
Mudflat Monitoring (Sedimentation rate)
Site Inspection
4, 11, 13 and 18 March 2019
21 and 22 March
2019
21 March 2019
1, 6, 13, 20 and 29 March 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 team’s observation on 24 March 2014, the original
monitoring location of IS(Mf)9 was no longer enclosed
by the perimeter silt curtain of Contract HY/2010/02. Thus, the impact water
quality monitoring works at the original monitoring location of IS(Mf)9 has been resumed since 24 March 2014.
Transect lines 1, 2, 7, 8,
9 and 11 for dolphin monitoring have been revised due to the obstruction of the
permanent structures associated with the construction works of HKLR and the
southern viaduct of TM-CLKL, as well as provision of adequate buffer distance
from the Airport Restricted Areas.The EPD issued a memo and confirmed that they had no objection on the
revised transect lines on 19 August 2015.
The water quality
monitoring stations at IS10 (Coordinate: 812577E, 820670N) and SR5 (811489E,
820455N) are located inside Hong Kong International Airport (HKIA) Approach
Restricted Areas. The previously granted Vessel's Entry Permit for accessing
stations IS10 and SR5 were expired on 31 December 2016. During the permit
renewing process, the water quality monitoring location was shifted to IS10(N)
(Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E, 820978N) on 2,
4 and 6 January 2017 temporarily. The permit has been granted by Marine
Department on 6 January 2017. Thus, the impact water quality monitoring works
at original monitoring location of IS10 and SR5 has been resumed since 9
January 2017.
Transect lines 2, 3, 4, 5,
6 and 7 for dolphin monitoring have been revised and transect line 24 has been
added due to the presence of a work zone to the north of the airport platform
with intense construction activities in association with the construction of
the third runway expansion for the Hong Kong International Airport. The EPD
issued a memo and confirmed that they had no objection on the revised transect
lines on 28 July 2017. The alternative dolphin transect lines are adopted
starting from August’s dolphin monitoring.
A new water quality monitoring team has been employed for carrying out
water quality monitoring work for the Contract starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong
International Airport into a Three-Runway System (3RS Project), original
locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed
by works boundary of 3RS Project. Alternative impact water quality monitoring
stations, naming as CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and
were adopted starting from 23 August 2017 to replace the original locations of
water quality monitoring for the Contract.
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.
The topographical condition of the water monitoring
stations SR3 (Coordinate: 810525E, 816456N), SR4 (Coordinate: 814760E,
817867N), SR10A (Coordinate: 823741E, 823495N) and SR10B (Coordinate: 823686E,
823213N) cannot be accessed safely for undertaking water quality monitoring.
The water quality monitoring has been temporarily conducted at alternative
stations, namely SR3(N) (Coordinate 810689E, 816591N), SR4(N) (Coordinate:
814705E, 817859N) and SR10A(N) (Coordinate: 823644E, 823484N) since 1 September
2017. The water quality monitoring at station SR10B was temporarily conducted
at Coordinate: 823683E, 823187N on 1, 4, 6, 8 September 2017 and has been
temporarily fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E,
823159N) since 11 September 2017. Proposal for permanently relocating the
aforementioned stations was approved by EPD on 8 January 2018.
According to
latest information received in July 2018, the works area WA7 was handed over to
other party on 28 February 2018 instead of 31 January 2018.
The future key issues
include potential noise, air quality, water quality and ecological impacts and
waste management arising from the following construction activities to be
undertaken in the upcoming month:
·Dismantling/ trimming of Temporary 40mm Stone Platform for Construction
of Seawall at Portion X;
·Construction of Seawall at
Portion X;
·Loading and Unloading
Filling Materials at Portion X;
·Works for Diversion of
Airport Road;
·Establishment of Site
Access at Airport Road / Airport Express Line/ East Coast Road;
·E&M / Landscaping works
at Airport Road;
·Finishing Works for
Highway Operation and Maintenance Area Building at Portion X; and
·Finishing Works for
Scenic Hill Tunnel West Portal Ventilation building at West Portal.
1.1.2The HKLR project has been
separated into two contracts.They
are Contract
No. HY/2011/03 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section
between Scenic Hill and Hong Kong Boundary Crossing Facilities (hereafter
referred to as the Contract) and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao
Bridge Hong Kong Link Road-Section between HKSAR Boundary and Scenic Hill.
1.1.3China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department (HyD) as the
Contractor to undertake the construction works of Contract No. HY/2011/03. The
Contract is part of the HKLR Project and HKBCF Project, these projects are
considered to be “Designated Projects”, under Schedule 2 of the Environmental
Impact Assessment (EIA) Ordinance (Cap 499) and Environmental Impact Assessment
(EIA) Reports (Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared
for the Project. The current Environmental Permit (EP) EP-352/2009/D for HKLR
and EP-353/2009/K for HKBCF were issued on 22 December 2014 and 11 April 2016,
respectively. These documents are available through the EIA Ordinance Register.
The construction phase of Contract was commenced on 17 October 2012. 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.
1.1.4The Contract includes the following key aspects:
·New reclamation along
the east coast of the approximately 23 hectares.
·Tunnel of Scenic Hill
(Tunnel SHT) from Scenic Hill to the new reclamation, of approximately 1km in
length with three (3) lanes for the east bound carriageway heading to the HKBCF
and four (4) lanes for the westbound carriageway heading to the HZMB Main
Bridge.
·An abutment of the
viaduct portion of the HKLR at the west portal of Tunnel SHT and associated
road works at the west portal of Tunnel SHT.
·An at grade road on
the new reclamation along the east coast of the HKIA to connect with the HKBCF,
of approximately 1.6 km along dual 3-lane carriageway with hard shoulder for
each bound.
·Road links between
the HKBCF and the HKIA including new roads and the modification of existing
roads at the HKIA, involving viaducts, at grade roads and a Tunnel HAT.
·A highway operation
and maintenance area (HMA) located on the new reclamation, south of the Dragonair Headquarters Building, including the construction
of buildings, connection roads and other associated facilities.
·Associated civil,
structural, building, geotechnical, marine, environmental protection,
landscaping, drainage and sewerage, tunnel and highway electrical and
mechanical works, together with the installation of street lightings, traffic
aids and sign gantries, water mains and fire hydrants, provision of facilities
for installation of traffic control and surveillance system (TCSS), reprovisioning works of affected existing facilities, implementation
of transplanting, compensatory planting and protection of existing trees, and
implementation of an environmental monitoring and audit (EM&A) program.
1.1.5This is the seventy-eighth Monthly EM&A report for the Contract which summarizes the monitoring
results and audit findings of the EM&A programme
during the reporting period from 1 to 31 March 2019.
1.1.6BMT 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.
1.2.1The project
organization structure and lines of communication with respect to the on-site
environmental management structure is shown in Appendix A.The key
personnel contact names and numbers are summarized in Table 1.1.
Supervising
Officer’s Representative
(Ove Arup & PartnersHong Kong Limited)
(Chief Resident Engineer, CRE)
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
---
1.3Construction Programme
1.3.1A copy of the Contractor’s construction programme is provided in Appendix B.
1.4Construction Works Undertaken During the
Reporting Month
1.4.1A summary of the construction activities undertaken
during this reporting month is shown in
Table 1.2.
Table 1.2Construction
Activities During Reporting Month
Description of Activities
Site Area
Dismantling/trimming
of temporary 40mm stone platform for construction of seawall
Portion X
Construction
of seawall
Portion X
Loading
and unloading of filling materials
Portion X
Works for diversion
Airport Road
Establishment of site access
Airport Road/ Airport Express
Line/ East Coast Road
Finishing
works for Highway Operation and Maintenance Area Building
Portion X
Finishing
works for Scenic Hill Tunnel West Portal Ventilation building
West Portal
2Air Quality Monitoring
2.1Monitoring
Requirements
2.1.1In accordance with
the Contract Specific EM&A Manual, baseline 1-hour and 24-hour TSP levels
at two air quality monitoring stations were established.Impact 1-hour TSP monitoring was
conducted for at least three times every 6 days, while impact 24-hour TSP
monitoring was carried out for at least once every 6 days.The Action and Limit Level for 1-hr TSP
and 24-hr TSP are provided in Table 2.1 and
Table 2.2, respectively.
2.2.124-hour TSP air
quality monitoring was performed using High Volume Sampler (HVS) located at each
designated monitoring station. The HVS meets all the requirements of the
Contract Specific EM&A Manual.Portable direct reading dust meters were used to carry out the 1-hour
TSP monitoring.Brand and model of
the equipment is given in Table 2.3.
Table 2.3Air
Quality Monitoring Equipment
Equipment
Brand and Model
Portable direct reading dust meter (1-hour
TSP)
Sibata Digital Dust 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)
(a)The HVS was installed in the vicinity of the air sensitive receivers.
The following criteria were considered in the installation of the HVS.
(i)A horizontal platform with appropriate support to secure the sampler
against gusty wind was provided.
(ii)The distance between the HVS and any obstacles, such as buildings, was
at least twice the height that the obstacle protrudes above the HVS.
(iii)A minimum of 2 meters separation from walls, parapets and penthouse for
rooftop sampler was provided.
(iv)No furnace or incinerator flues are nearby.
(v)Airflow around the sampler was unrestricted.
(vi)Permission was obtained to set up the samplers and access to the
monitoring stations.
(vii)A secured supply of electricity was obtained to operate the samplers.
(viii)The sampler was located more than 20 meters from any dripline.
(ix)Any wire fence and gate, required to protect the sampler, did not
obstruct the monitoring process.
(x)Flow control accuracy was kept within ±2.5% deviation over 24-hour sampling
period.
(b)Preparation of Filter Papers
(i)Glass fibre filters, G810 were labelled and sufficient filters that were
clean and without pinholes were selected.
(ii)All filters were equilibrated in the conditioning environment for 24
hours before weighing. The conditioning environment temperature was around 25 °C and not variable by more than ±3 °C; the relative humidity (RH) was < 50%
and not variable by more than ±5%.A convenient working RH was 40%.
(iii)All filter papers were prepared and analysed by ALS Technichem
(HK) Pty Ltd., which is a HOKLAS accredited laboratory and has comprehensive
quality assurance and quality control programmes.
(c)Field Monitoring
(i)The power supply was checked to ensure the HVS works properly.
(ii)The filter holder and the area surrounding the filter were cleaned.
(iii)The filter holder was removed by loosening the four bolts and a new
filter, with stamped number upward, on a supporting screen was aligned
carefully.
(iv)The filter was properly aligned on the screen so that the gasket formed
an airtight seal on the outer edges of the filter.
(v)The swing bolts were fastened to hold the filter holder down to the
frame.The pressure applied was
sufficient to avoid air leakage at the edges.
(vi)Then the shelter lid was closed and was secured with the aluminium
strip.
(vii)The HVS was warmed-up for about 5 minutes to establish run-temperature
conditions.
(viii)A new flow rate record sheet was set into the flow recorder.
(ix)On site temperature and atmospheric pressure readings were taken and the
flow rate of the HVS was checked and adjusted at around 1.1 m3/min,
and complied with the range specified in the Updated EM&A Manual for HKLR
(Version 1.0) (i.e. 0.6-1.7 m3/min).
(x)The programmable digital timer was set for a sampling period of 24
hours, and the starting time, weather condition and the filter number were
recorded.
(xi)The initial elapsed time was recorded.
(xii)At the end of sampling, on site temperature and atmospheric pressure readings
were taken and the final flow rate of the HVS was checked and recorded.
(xiii)The final elapsed time was recorded.
(xiv)The sampled filter was removed carefully and folded in half length so that only surfaces with collected
particulate matter were in contact.
(xv)It was then placed in a clean plastic envelope and sealed.
(xvi)All monitoring information was recorded on a standard data sheet.
(xvii)Filters were then sent to ALS Technichem (HK)
Pty Ltd. for analysis.
(d)Maintenance and Calibration
(i)The HVS and its accessories were maintained in good working condition,
such as replacing motor brushes routinely and checking electrical wiring to
ensure a continuous power supply.
(ii)5-point calibration of the HVS was conducted using TE-5025A Calibration Kit prior to the
commencement of baseline monitoring. Bi-monthly 5-point calibration of the HVS
will be carried out during impact monitoring.
(iii)Calibration certificate of the HVSs are provided in Appendix C.
2.5.21-hour TSP
Monitoring
(a)Measuring Procedures
The measuring procedures of
the 1-hour dust meter were in accordance with the Manufacturer’s Instruction
Manual as follows:-
(i)Turn the power on.
(ii)Close the air collecting opening cover.
(iii)Push the “TIME SETTING” switch to [BG].
(iv)Push “START/STOP” switch to perform background measurement for 6
seconds.
(v)Turn the knob at SENSI ADJ position to insert the light scattering
plate.
(vi)Leave the equipment for 1 minute upon “SPAN CHECK” is indicated in the
display.
(vii)Push “START/STOP” switch to perform automatic sensitivity adjustment.
This measurement takes 1 minute.
(viii)Pull out the knob and return it to MEASURE position.
(ix)Push the “TIME SETTING” switch the time set in the display to 3 hours.
(x)Lower down the air collection opening cover.
(xi)Push “START/STOP” switch to start measurement.
(b)Maintenance
and Calibration
(i)The
1-hour TSP meter was calibrated at 1-year intervals against a Tisch
Environmental Mass Flow Controlled Total Suspended Particulate (TSP) High
Volume Air Sampler. Calibration certificates of the Laser Dust Monitors are
provided in Appendix C.
Table 2.6Summary
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
61
40 – 118
352
500
AMS6
70
37 – 241
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
54
17 – 79
164
260
AMS6
57
19 – 93
173
260
2.7.2No 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.
2.7.3The
wind data obtained from the on-site weather station
during the reporting month is
shown in Appendix G.
3.1.1In accordance with
the Contract Specific EM&A Manual, impact noise monitoring was conducted
for at least once per week during the construction phase of the Project. The
Action and Limit level of the noise monitoring is provided in Table 3.1.
Table 3.1Action
and Limit Levels for Noise during Construction Period
Monitoring Station
Time Period
Action Level
Limit Level
NMS5 – Ma Wan Chung
Village (Ma Wan Chung Resident Association) (Tung Chung)
0700-1900 hours on normal
weekdays
When one documented
complaint is received
75 dB(A)
3.2Monitoring Equipment
3.2.1Noise monitoring was
performed using sound level meters at each designated monitoring station.The sound level meters deployed comply
with the International Electrotechnical Commission Publications (IEC) 651:1979
(Type 1) and 804:1985 (Type 1) specifications.Acoustic calibrator was deployed to
check the sound level meters at a known sound pressure level.Brand and model of the equipment are
given in Table 3.2.
Table 3.2 Noise
Monitoring Equipment
Equipment
Brand and Model
Integrated Sound Level
Meter
B&K 2238
Acoustic Calibrator
B&K 4231
3.3Monitoring
Locations
3.3.1Monitoring location NMS5 was set up at the
proposed locations in accordance with Contract Specific EM&A Manual.
3.3.2Figure
2.1shows the locations
of monitoring stations. Table 3.3 describes the details of the monitoring
stations.
Table 3.3Locations
of Impact Noise Monitoring Stations
Monitoring Station
Location
NMS5
Ma Wan Chung Village (Ma Wan
Chung Resident Association) (Tung Chung)
(a)The sound level meter was
set on a tripod at a height of 1.2 m
above the podium for free-field
measurements at NMS5. A correction of +3 dB(A) shall be made to
the free field measurements.
(b)The battery condition was
checked to ensure the correct functioning of the meter.
(c)Parameters such as
frequency weighting, the time weighting and the measurement time were set as
follows:-
(i)frequency
weighting: A
(ii)time weighting: Fast
(iii)time
measurement: Leq(30-minutes) during
non-restricted hours i.e. 07:00 – 1900 on normal weekdays
(d)Prior to and after each
noise measurement, the meter was calibrated using the acoustic calibrator for
94.0 dB(A) at 1000 Hz.If the
difference in the calibration level before and after measurement was more than
1.0 dB(A), the measurement would be considered invalid and repeat of noise
measurement would be required after re-calibration or repair of the equipment.
(e)During the monitoring
period, the Leq, L10 and L90
were recorded.In addition, site
conditions and noise sources were recorded on a standard record sheet.
(f)Noise measurement was
paused during periods of high intrusive noise (e.g. dog barking, helicopter
noise) if possible. Observations were recorded when intrusive noise was
unavoidable.
(g)Noise monitoring was
cancelled in the presence of fog, rain, wind with a steady speed exceeding 5m/s, or wind with gusts exceeding 10m/s. The wind speed shall be checked with a
portable wind speed meter capable of measuring the wind speed in m/s.
3.5.2Maintenance and Calibration
(a) The microphone head of the sound level
meter was cleaned with soft cloth at regular intervals.
(b)The meter and calibrator
were sent to the supplier or HOKLAS laboratory to check and calibrate at yearly
intervals.
(c)Calibration certificates
of the sound level meters and acoustic calibrators are provided in Appendix C.
3.6.1The schedule for construction
noise monitoring in March2019 is provided in Appendix D.
3.7Monitoring
Results
3.7.1The monitoring
results for construction noise are summarized in Table 3.5 and the monitoring results and relevant graphical plots
are provided in Appendix E.
4.1.1Impact water quality monitoring was carried out to
ensure that any deterioration of water quality is detected, and that timely
action is taken to rectify the situation.For impact water quality monitoring, measurements were taken in
accordance with the Contract Specific EM&A Manual. Table 4.1 shows the established Action/Limit Levels for the
environmental monitoring works.The ET proposed to amend the Acton Level
and Limit Level for turbidity and suspended solid and EPD approved ET’s
proposal on 25 March 2013.Therefore, Action Level and Limit Level for the Contract have been
changed since 25 March 2013.
4.1.2The original and revised Action Level and
Limit Level for turbidity and suspended solid are shown in Table 4.1.
Table 4.1Action
and Limit Levels for Water Quality
Parameter (unit)
Water Depth
Action Level
Limit Level
Dissolved Oxygen (mg/L)
(surface, middle and bottom)
Surface and Middle
5.0
4.2 except 5 for Fish
Culture Zone
Bottom
4.7
3.6
Turbidity (NTU)
Depth average
27.5 or 120% of upstream
control station’s turbidity at the same tide of the same day;
The action level has been
amended to “27.5 and 120% of upstream control station’s turbidity at the same
tide of the same day” since 25 March 2013.
47.0 or 130% of turbidity
at the upstream control station at the same tide of same day;
The limit level has been
amended to “47.0 and 130% of turbidity at the upstream control station at the
same tide of same day” since 25 March 2013.
Suspended Solid (SS)
(mg/L)
Depth average
23.5 or 120% of upstream
control station’s SS at the same tide of the same day;
The action level has been
amended to “23.5 and 120% of upstream control station’s SS at the same tide of
the same day” since 25 March 2013.
34.4 or 130% of SS at the
upstream control station at the same tide of same day and 10mg/L for Water
Services Department Seawater Intakes;
The limit level has been
amended to “34.4 and 130% of SS at the upstream control station at the same
tide of same day and 10mg/L for Water Services Department Seawater Intakes”
since 25 March 2013
Notes:
(1)Depth-averaged
is calculated by taking the arithmetic means of reading of all three depths.
(2)For DO,
non-compliance of the water quality limit occurs when monitoring result is
lower that the limit.
(3)For SS &
turbidity non-compliance of the water quality limits occur when monitoring
result is higher than the limits.
(4)The change to
the Action and limit Levels for Water Quality Monitoring for the EM&A works
was approved by EPD on 25 March 2013.
4.3.1Table 4.3 summarizes the monitoring parameters, frequency and
monitoring depths of impact water quality monitoring as required in the
Contract Specific EM&A Manual.
Table 4.3Impact
Water Quality Monitoring Parameters and Frequency
Three times per week
during mid-ebb and mid-flood tides (within ± 1.75 hour of the predicted time)
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth
be less than 3 m, only the mid-depth station will be monitored).
4.4.1In accordance with the Contract Specific EM&A Manual, thirteen
stations (6 Impact Stations, 5 Sensitive Receiver Stations and 2 Control Stations) were
designated for impact water quality monitoring.The six Impact Stations (IS) were chosen
on the basis of their proximity to the reclamation and thus the greatest
potential for water quality impacts, the five Sensitive Receiver Stations (SR)
were chosen as they are close to the key sensitive receives and the two Control
Stations (CS) were chosen to facilitate comparison of the water quality of the
IS stations with less influence by the Project/ ambient water quality
conditions.
4.4.2A 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.
4.4.3The 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.
4.4.4The locations of water quality monitoring stations
during the reporting period are summarized in Table 4.4 and shown in Figure
2.1.
Table 4.4 Impact
Water Quality Monitoring Stations
Monitoring Stations
Description
Coordinates
Easting
Northing
IS5
Impact Station (Close to
HKLR construction site)
811579
817106
IS(Mf)6
Impact Station (Close to
HKLR construction site)
812101
817873
IS7
Impact Station (Close to
HKBCF construction site)
812244
818777
IS8
Impact Station (Close to
HKBCF construction site)
814251
818412
IS(Mf)9
Impact Station (Close to
HKBCF construction site)
813273
818850
IS10(N)
Impact Station (Close to
HKBCF construction site)
812942
820881
SR3(N)
Sensitive receivers (San
Tau SSSI)
810689
816591
SR4(N)
Sensitive receivers (Tai
Ho Inlet)
814705
817859
SR5(N)
Sensitive Receivers
(Artificial Reef in NE Airport)
812569
821475
SR10A(N)
Sensitive receivers (Ma
Wan Fish Culture Zone)
823644
823484
SR10B(N2)
Sensitive receivers (Ma
Wan Fish Culture Zone)
823689
823159
CS2(A)
Control Station (Mid-Ebb)
805232
818606
CS(Mf)5
Control Station
(Mid-Flood)
817990
821129
Remarks:
1) The access to station
SR4(N) was blocked by silt curtains in all water monitoring date of March
2019. As such, the water quality monitoring at station SR4(N) was temporarily
conducted at a location which is close to the original coordinates of station
SR4(N) as far as practicable in March 2019.
2) The access to station IS8
was blocked by silt curtains starting from 8 Mar 2019 onwards. As such, the
water quality monitoring at station IS8 was temporarily conducted at a
location which is close to the original coordinates of station IS8 as far as
practicable starting from 8 Mar 2019 onwards.
4.5Monitoring
Methodology
4.5.1Instrumentation
(a)The in-situ
water quality parameters including dissolved oxygen, temperature, salinity and
turbidity, pH were measured by multi-parameter meters.
4.5.2Operating/Analytical
Procedures
(a)Digital Differential Global Positioning Systems
(DGPS) were used to ensure that the correct location was selected prior to
sample collection.
(b)Portable, battery-operated echo sounders were used
for the determination of water depth at each designated monitoring station.
(c)All in-situ measurements were taken at 3 water depths,
1 m below water surface, mid-depth and 1 m above sea bed, except where the
water depth was less than 6 m, in which case the mid-depth station was omitted.
Should the water depth be less than 3 m, only the mid-depth station was
monitored.
(d)At each measurement/sampling depth, two consecutive
in-situ monitoring (DO concentration and saturation, temperature, turbidity,
pH, salinity) and water sample for SS. The probes were retrieved out of the
water after the first measurement and then re-deployed for the second
measurement. Where the difference in the value between the first and second
readings of DO or turbidity parameters was more than 25% of the value of the
first reading, the reading was discarded and further readings were taken.
(e)Duplicate samples from each independent sampling
event were collected for SS measurement. Water samples were collected using the
water samplers and the samples were stored in high-density polythene bottles.
Water samples collected were well-mixed in the water sampler prior to
pre-rinsing and transferring to sample bottles. Sample bottles were pre-rinsed
with the same water samples. The sample bottles were then be packed in
cool-boxes (cooled at 4oC without being frozen), and delivered to
ALS Technichem (HK) Pty Ltd. for the analysis of
suspended solids concentrations. The laboratory determination work would be
started within 24 hours after collection of the water samples. ALS Technichem (HK) Pty Ltd. is a HOKLAS accredited laboratory
and has comprehensive quality assurance and quality control programmes.
(f)The analysis method and detection limit for SS is
shown in Table 4.5.
Table 4.5Laboratory Analysis for Suspended
Solids
Parameters
Instrumentation
Analytical Method
Detection Limit
Suspended Solid (SS)
Weighting
APHA 2540-D
0.5mg/L
(g)Other relevant data were recorded, including
monitoring location / position, time, water depth, tidal stages, weather
conditions and any special phenomena or work underway at the construction site in
the field log sheet for information.
4.5.3Maintenance and
Calibrations
(a)All in situ monitoring
instruments would be calibrated by ALS Technichem
(HK) Pty Ltd. before use and at 3-monthly intervals throughout all stages of
the water quality monitoring programme. The
procedures of performance check of sonde and testing
results are provided in Appendix C.
4.6.1The schedule for impact water quality monitoring in March2019 is provided in Appendix D.
4.7Monitoring
Results
4.7.1Impact water quality
monitoring was conducted at all designated monitoring stations during the
reporting month. Impact water quality monitoring results and relevant graphical
plots are provided inAppendix E.
4.7.2Water quality impact sources during water quality monitoring were nearby
construction activities by other parties and nearby operating vessels by other
parties.
4.7.3For marine water quality monitoring, no
Action Level and Limit Level exceedances of dissolved oxygen level and
turbidity level were recorded during the reporting month. Also, no Limit Level exceedances of suspended solids level were recorded during
the reporting month.
4.7.4Two Action Level exceedances of
suspended solids level were recorded during the reporting month.
4.7.5Number of exceedances recorded
during the reporting month at each impact station are summarized in Table 4.6.
Table 4.6Summary
of Water Quality Exceedances
Station
Exceedance Level
DO
(S&M)
DO
(Bottom)
Turbidity
SS
Total number of
exceedances
Ebb
Flood
Ebb
Flood
Ebb
Flood
Ebb
Flood
Ebb
Flood
IS5
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS(Mf)6
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS7
Action Level
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS8
Action Level
--
--
--
--
--
--
25-03-2019
--
1
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS(Mf)9
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
IS10(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR3(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR4(N)
Action Level
--
--
--
--
--
--
25-03-2019
--
1
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR5(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR10A(N)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
SR10B(N2)
Action Level
--
--
--
--
--
--
--
--
0
0
Limit Level
--
--
--
--
--
--
--
--
0
0
Total
Action
0
0
0
0
0
0
2
0
2**
Limit
0
0
0
0
0
0
0
0
0**
Notes:
S: Surface;
M: Mid-depth;
**The
total number of
exceedances
4.7.6The exceedances suspended solid
level recorded during reporting period were considered to be
attributed to other external factors such as sea condition, rather than the
contract works. Therefore, the exceedances were considered as non-contract
related. Records of “Notification of Environmental Quality Limit Exceedances”
are provided in Appendix N.
4.7.7The event action plan is annexed
in Appendix F.
5.1.1Impact dolphin monitoring is required to be conducted by a qualified dolphin specialist team to
evaluate whether there have
been any effects on the
dolphins.
5.1.2The Action Level and Limit Level for dolphin
monitoring are shown in Table 5.1.
Table
5.1Action
and Limit Levels for Dolphin Monitoring
North Lantau Social Cluster
NEL
NWL
Action
Level
STG < 4.2 & ANI < 15.5
STG < 6.9 & ANI <
31.3
Limit Level
(STG < 2.4 & ANI
< 8.9) and (STG < 3.9 & ANI < 17.9)
Remarks:
1.STG means quarterly encounter rate of number of dolphin sightings.
2.ANI means quarterly encounter rate of total number of dolphins.
3.For North Lantau Social Cluster, AL will be trigger if either NEL or NWL fall below the criteria; LL will
be triggered if both NEL and NWL
fall below the criteria.
5.1.3The revised Event and Action Plan
for dolphin Monitoring was approved by EPD in 6 May 2013. The revised Event and Action
Plan is annexed in Appendix F.
5.2.1According to the
requirement of the updated EM&A manual, dolphin monitoring programme should
cover all transect lines in NEL and NWL survey areas (see Figure 1 of Appendix H) twice per month throughout the entire construction period.The co-ordinates of all transect lines
are shown in Table 5.2. The coordinates of several starting and ending points have
been revised due to the presence of a work zone to the north of the airport
platform with intense construction activities in association with the
construction of the third runway expansion for the Hong Kong International
Airport.The EPD issued a memo and
confirmed that they had no objection on the revised transect lines on 28 July
2017, and the revised coordinates are in red and marked with an asterisk in
Table 5.2.
Table 5.2Co-ordinates
of Transect Lines
Line No.
Easting
Northing
Line No.
Easting
Northing
1
Start Point
804671
815456
13
Start Point
816506
819480
1
End Point
804671
831404
13
End Point
816506
824859
2
Start Point
805476
820800*
14
Start Point
817537
820220
2
End Point
805476
826654
14
End Point
817537
824613
3
Start Point
806464
821150*
15
Start Point
818568
820735
3
End Point
806464
822911
15
End Point
818568
824433
4
Start Point
807518
821500*
16
Start Point
819532
821420
4
End Point
807518
829230
16
End Point
819532
824209
5
Start Point
808504
821850*
17
Start Point
820451
822125
5
End Point
808504
828602
17
End Point
820451
823671
6
Start Point
809490
822150*
18
Start Point
821504
822371
6
End Point
809490
825352
18
End Point
821504
823761
7
Start Point
810499
822000*
19
Start Point
822513
823268
7
End Point
810499
824613
19
End Point
822513
824321
8
Start Point
811508
821123
20
Start Point
823477
823402
8
End Point
811508
824254
20
End Point
823477
824613
9
Start Point
812516
821303
21
Start Point
805476
827081
9
End Point
812516
824254
21
End Point
805476
830562
10
Start Point
813525
821176
22
Start Point
806464
824033
10
End Point
813525
824657
22
End Point
806464
829598
11
Start Point
814556
818853
23
Start Point
814559
821739
11
End Point
814556
820992
23
End Point
814559
824768
12
Start Point
815542
818807
24*
Start Point
805476*
815900*
12
End Point
815542
824882
24*
End Point
805476*
819100*
Note:
Co-ordinates in red and marked with asterisk are revised co-ordinates of
transect line.
5.2.2The survey team used standard line-transect methods
(Buckland et al. 2001) to conduct the systematic vessel surveys, and followed
the same technique of data collection that has been adopted over the last 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.
5.2.3Two experienced observers (a data recorder and a
primary observer) made up the on-effort survey team, and the survey vessel
transited different transect lines at a constant speed of 13-15 km per
hour.The data recorder searched
with unaided eyes and filled out the datasheets, while the primary observer
searched for dolphins and porpoises continuously through 7 x 50 Fujinon marine
binoculars.Both observers searched
the sea ahead of the vessel, between 270o and 90o (in
relation to the bow, which is defined as 0o).One to two additional experienced
observers were available on the boat to work in shift (i.e. rotate every 30
minutes) in order to minimize fatigue of the survey team members. All observers
were experienced in small cetacean survey techniques and identifying local
cetacean species.
5.2.4During on-effort survey periods, the survey team
recorded effort data including time, position (latitude and longitude), weather
conditions (Beaufort sea state and visibility), and distance traveled in each
series (a continuous period of search effort) with the assistance of a handheld
GPS (Garmin eTrex
Legend).
5.2.5Data including time, position and vessel speed were
also automatically and continuously logged by handheld GPS throughout the
entire survey for subsequent review.
5.2.6When dolphins were sighted, the survey team would
end the survey effort, and immediately record the initial sighting distance and
angle of the dolphin group from the survey vessel, as well as the sighting time
and position. Then the research vessel was diverted from its course to approach
the animals for species identification, group size estimation, assessment of
group composition, and behavioural observations. The
perpendicular distance (PSD) of the dolphin group to the transect line was
later calculated from the initial sighting distance and angle.
5.2.7Survey effort being conducted along the parallel
transect lines that were perpendicular to the coastlines (as indicated in Figure 1 of Appendix H) was
labeled as “primary” survey effort, while the survey effort conducted along the
connecting lines between parallel lines was labeled as “secondary” survey
effort. According to HKCRP long-term dolphin monitoring data, encounter rates
of Chinese white dolphins deduced from effort and sighting data collected along
primary and secondary lines were similar in NEL and NWL survey areas.Therefore, both primary and secondary
survey effort were presented as on-effort survey effort in this report.
5.2.8Encounter rates of Chinese white dolphins (number
of on-effort sightings per 100 km of survey effort and number of dolphins from
all on-effort sightings per 100 km of survey effort) were calculated in NEL and
NWL survey areas in relation to the amount of survey effort conducted during
each month of monitoring survey. Only data collected under Beaufort 3 or below
condition would be used for encounter rate analysis.Dolphin encounter rates were calculated
using primary survey effort alone, as well as the combined survey effort from
both primary and secondary lines.
Photo-identification Work
5.2.9When a group of Chinese White Dolphins were sighted
during the line-transect survey, the survey team would end effort and approach
the group slowly from the side and behind to take photographs of them.Every attempt was made to photograph
every dolphin in the group, and even photograph both sides of the dolphins,
since the colouration and markings on both sides may
not be symmetrical.
5.2.10A professional digital camera (Canon EOS 7D model), equipped with long telephoto lenses (100-400
mm zoom), were available on board for researchers to take sharp, close-up
photographs of dolphins as they surfaced.The images were shot at the highest available resolution and stored on
Compact Flash memory cards for downloading onto a computer.
5.2.11All digital images taken in the field were first
examined, and those containing potentially identifiable individuals were sorted
out.These photographs would then
be examined in greater detail and were carefully compared to the existing
Chinese White Dolphin photo-identification catalogue maintained by HKCRP since
1995.
5.2.12Chinese White Dolphins can be identified by their
natural markings, such as nicks, cuts, scars and deformities on their dorsal
fin and body, and their unique spotting patterns were also used as secondary
identifying features (Jefferson 2000).
5.2.13All
photographs of each individual were then compiled and arranged in chronological
order, with data including the date and location first identified (initial
sighting), re-sightings, associated dolphins, distinctive features, and age
classes entered into a computer database.Detailed information on all identified individuals will be further
presented as an appendix in quarterly EM&A reports.
5.3.1During the month of March 2019, two sets
of systematic line-transect vessel surveys were conducted on the 4th,
11th, 13th and 18th to cover all transect
lines in NWL and NEL survey areas twice. The survey routes of each survey day
are presented in Figures
2 to 5 of Appendix H.
5.3.2From these surveys, a total of 259.07 km of survey effort was collected,
with 95.6% 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).
5.3.3Among the
two survey areas, 93.50 km and 165.57 km of survey effort were collected from
NEL and NWL survey areas respectively. Moreover, the total survey effort
conducted on primary lines was 185.51 km, while the effort on secondary lines
was 73.56 km.
5.3.4During the two sets of monitoring surveys in March
2019, only three groups of six Chinese White Dolphins were sighted (see Annex II of Appendix H). All three
dolphin sightings were made in NWL, while none was sighted in NEL.
5.3.5All three
dolphin groups were sighted during on-effort search, with two of them being
sighted on primary lines (Annex II of Appendix H). Notably, none of the dolphin groups was associated with any
operating fishing vessel.
5.3.6Distribution of the three dolphin sightings made in
March 2019 is shown in Figure 6of Appendix H. The three
groups were sighted at the northwestern and southwestern
corners of NWL survey area and near Black Point respectively (Figure 6of Appendix H).
5.3.7During the
March’s surveys, encounter rates of Chinese White Dolphins deduced from the
survey effort and on-effort sighting data made under favourable conditions
(Beaufort 3 or below) are shown in Tables 5.3 and 5.4.
Table 5.3Individual Survey Event
Encounter Rates
Encounter
rate (STG)
(no. of on-effort dolphin sightings per 100
km of survey effort)
Encounter
rate (ANI)
(no. of dolphins from all on-effort sightings
per 100 km of survey effort)
Primary Lines Only
Primary Lines Only
NEL
Set
1: March 4th / 11th
0.0
0.0
Set2: March13th
/ 18th
0.0
0.0
NWL
Set 1: March 4th
/ 11th
0.0
0.0
Set2: March13th
/ 18th
3.4
6.8
Remark:
1.Dolphin Encounter Rates Deduced from the Two
Sets of Surveys in March 2019 in Northeast Lantau (NEL) and Northwest Lantau
(NWL).
Table 5.4Monthly
Average Encounter Rates
Encounter rate (STG)
(no.
of on-effort dolphin sightings per 100 km of survey effort)
Encounter rate (ANI)
(no.
of dolphins from all on-effort sightings per 100 km of survey effort)
PrimaryLines Only
Both Primary and Secondary Lines
PrimaryLines Only
Both Primary and Secondary Lines
Northeast
Lantau
0.0
0.0
0.0
0.0
Northwest
Lantau
1.7
1.8
3.4
3.6
Remark:
1.Monthly Average Dolphin Encounter Rates (Sightings Per 100 km of
Survey Effort) from the Two Sets of Surveys Conducted in March 2019 on Primary Lines only as well as Both Primary Lines
and Secondary Lines in Northeast Lantau (NEL) and Northwest Lantau (NWL).
5.3.8The
average dolphin group size in March 2019 was 2.0 individuals per group, which
was lower than the averages in the previous monitoring months. All three groups
were composed of small groups of two animals only(Annex II of Appendix H).
Photo-identification Work
5.3.9Each of the three known individual dolphins was
re-sighted once during the March’s surveys (Annexes III and IV of Appendix H).
5.3.10Notably, during their
re-sightings in March 2019, one identified individual (WL145) was sighted with
her young calf.
Conclusion
5.3.11During this month of dolphin monitoring, no adverse impact
from the activities of this construction project on Chinese White Dolphins was
noticeable from general observations.
5.3.12Due to monthly variation in dolphin occurrence within
the study area, it would be more appropriate to draw conclusion on whether any
impacts on dolphins have been detected related to the construction activities
of this project in the quarterly EM&A report, where comparison on
distribution, group size and encounter rates of dolphins between the quarterly
impact monitoring period (March-May 2019) and the 3-month baseline monitoring
period will be made.
5.4Reference
5.4.1Buckland,
S. T., Anderson, D. R., Burnham, K. P., Laake, J. L.,
Borchers, D. L., and Thomas, L.2001.Introduction to
distance sampling: estimating abundance of biological populations.Oxford University Press, London.
5.4.2Hung,
S. K.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.
5.4.3Jefferson, T. A.2000.Population biology of the Indo-Pacific
hump-backed dolphin in Hong Kong waters.Wildlife Monographs 144:1-65.
6.1.1To avoid disturbance
to the mudflat and nuisance to navigation, no fixed marker/monitoring rod was
installed at the monitoring stations. A high precision Global Navigation
Satellite System (GNSS) real time location fixing system (or equivalent
technology) was used to locate the station in the precision of 1mm, which is
reasonable under flat mudflat topography with uneven mudflat surface only at
micro level.This method has been
used on Agricultural Fisheries and Conservation Department’s (AFCD) project,
namely Baseline Ecological Monitoring Programme for the Mai Po Inner Deep Bay Ramsar
Site for measurement of seabed levels.
6.1.2Measurements were
taken directly on the mudflat surface. The Real Time Kinematic GNSS (RTK GNSS)
surveying technology was used to measure mudflat surface levels and 3D
coordinates of a survey point.The
RTK GNSS survey was calibrated against a reference station in the field before
and after each survey.The
reference station is a survey control point established by the Lands Department
of the HKSAR Government or traditional land surveying methods using professional
surveying instruments such as total station, level and/or geodetic GNSS.The coordinates system was in HK1980
GRID system.For this contract, the
reference control station was surveyed and established by traditional land
surveying methods using professional surveying instruments such as total
station, level and RTK GNSS.The
accuracy was down to mm level so that the reference control station has
relatively higher accuracy.As the
reference control station has higher accuracy, it was set as true evaluation
relative to the RTK GNSS measurement.All position and height correction were adjusted and corrected to the
reference control station.Reference station survey result and professional land surveying
calibration is shown as Table 6.1:
Table 6.1Reference
Station Survey result and GNSS RTK calibration result of Round 1
Reference Station
Easting (m)
Northing (m)
Baseline reference elevation (mPD) (A)
Round 1 Survey (mPD) (B)
Calibration Adjustment (B-A)
T1
811248.660mE
816393.173mN
3.840
3.817
-0.023
T2
810806.297mE
815691.822mN
4.625
4.653
+0.028
T3
810778.098mE
815689.918mN
4.651
4.660
+0.009
T4
810274.783mE
816689.068mN
2.637
2.709
+0.072
6.1.3The precision of the
measured mudflat surface level reading (vertical precision setting) was within 10
mm (standard deviation) after averaging the valid survey records of the XYZ
HK1980 GRID coordinates.Each
survey record at each station was computed by averaging at least three
measurements that are within the above specified precision setting. Both digital
data logging and written records were collected in the field.Field data on station fixing and mudflat
surface measurement were recorded.
Monitoring Locations
6.1.4Four monitoring
stations were established based on the site conditions for the sedimentation
monitoring and are shown in Figure
6.1.
Monitoring Results
6.1.5The baseline
sedimentation rate monitoring was in September 2012 and impact sedimentation
rate monitoring was undertaken on 21March 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 6.2Measured
Mudflat Surface Level Results
Baseline Monitoring
(September 2012)
Impact Monitoring
(December 2018)
Monitoring
Station
Easting
(m)
Northing
(m)
Surface
Level
(mPD)
Easting
(m)
Northing
(m)
Surface
Level
(mPD)
S1
810291.160
816678.727
0.950
810291.173
816678.733
1.191
S2
810958.272
815831.531
0.864
810958.272
815831.553
1.019
S3
810716.585
815953.308
1.341
810716.577
815953.305
1.550
S4
811221.433
816151.381
0.931
811221.381
816151.280
1.206
Table 6.3Comparison
of measurement
Comparison of measurement
Remarks
and Recommendation
Monitoring Station
Easting (m)
Northing (m)
Surface Level
(mPD)
S1
0.013
0.006
0.241
Level continuously increased
S2
0.000
0.022
0.155
Level continuously increased
S3
-0.008
-0.003
0.209
Level continuously increased
S4
-0.052
-0.101
0.275
Level continuously increased
6.1.6This measurement result was
generally and relatively higher than the baseline measurement at S1, S2, S3 and
S4. The mudflat level is continuously increased.
6.2.1The mudflat monitoring
covered water quality monitoring data.Reference was made to the water quality monitoring data of the
representative water quality monitoring station (i.e. SR3(N)) as in the
EM&A Manual. The water quality monitoring location (SR3(N)) is shown in Figure
2.1.
6.2.2Impact water quality
monitoring in San Tau (monitoring station SR3(N)) was conducted in March 2019.
The monitoring parameters included dissolved oxygen (DO), turbidity and
suspended solids (SS).
6.2.3The Impact
monitoring results for SR3(N) were extracted and summarised below:
Table 6.4Impact
Water Quality Monitoring Results (Depth Average)
6.3.1In order to collect baseline
information of mudflats in the study site, the study site was divided into three
sampling zones (labeled as TC1, TC2, TC3) in Tung Chung Bay and one zone in San
Tau (labeled as ST) (Figure 2.1 of Appendix I). The horizontal shoreline of sampling
zones TC1, TC2, TC3 and ST were about 250 m, 300 m, 300 m and 250 m
respectively (Figure 2.2 of Appendix I). Survey of horseshoe crabs, seagrass beds
and intertidal communities were conducted in every sampling zone. The present
survey was conducted in March 2019 (totally 2 sampling days on 21st
and 22nd March 2019).
6.3.2Since the field survey of Jun.
2016, increasing number of trashes and even big trashes (Figure 2.3 of Appendix I) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Bay. Respective measures (e.g. manual clean-up) should be
implemented by responsible government agency units.
Horseshoe Crabs
6.3.3Active 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 21st
and 22nd March 2019, which were warm and humid days.
6.3.4In 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 ‘fatal trap’ for the horseshoe crabs and other marine life. Manual
clean-up should be implemented as soon as possible by responsible units.
Seagrass Beds
6.3.5Active 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 21st (for
ST, TC2 and TC3) and 22nd (for TC1) March 2019, which were warm and
humid days.
Intertidal Soft Shore Communities
6.3.6The intertidal soft shore
community surveys were conducted in low tide period on 21st (for ST.
TC2 and TC3) and 22nd (for TC1) March 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.
6.3.7Inside 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 x 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.
6.3.8All 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.
6.3.9The
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
6.3.10Data collected from
direct counting and core sampling was pooled in every quadrat for data
analysis. Shannon-Weaver Diversity Index (H’) and Pielou’s
Species Evenness (J) were calculated for every quadrat using the formulae
below,
H’= -Σ ( Ni / N ) ln ( Ni / N ) (Shannon and Weaver, 1963)
J = H’ / ln S, (Pielou, 1966)
where S is the total number
of species in the sample, N is the total number of individuals, and Ni is the
number of individuals of the ith species.
6.4.1In the event of the impact
monitoring results indicating that the density or the distribution pattern of
intertidal fauna and seagrass is found to be significant different to the
baseline condition (taking into account natural fluctuation in the occurrence
and distribution pattern such as due to seasonal change), appropriate actions
should be taken and additional mitigation measures should be implemented as
necessary.Data should then be
re-assessed and the need for any further monitoring should be established. The
action plan, as given in Table 6.5
should be undertaken within a period of 1 month after a significant difference
has been determined.
Table 6.5Event
and Action Plan for Mudflat Monitoring
Event
ET
Leader
IEC
SO
Contractor
Density
or the distribution pattern of horseshoe crab, seagrass or intertidal soft
shore communities recorded in the impact or post-construction monitoring
aresignificantly lower than or
different from those recorded in the baseline monitoring.
Review
historical data to ensure differences are as a result of natural variation or
previously observed seasonal differences;
Identify
source(s) of impact;
Inform
the IEC, SO and Contractor;
Check
monitoring data;
Discuss
additional monitoring and any other measures, with the IEC and Contractor.
Discuss
monitoring with the ET and the Contractor;
Review
proposals for additional monitoring and any other measures submitted by the
Contractor and advise the SO accordingly.
Discuss
with the IEC additional monitoring requirements and any other measures
proposed by the ET;
Make
agreement on the measures to be implemented.
Inform
the SO and in writing;
Discuss
with the ET and the IEC and propose measures to the IEC and the ER;
6.5.13
individuals of horseshoe crab, Carcinoscorpiusrotundicauda, were found in present survey. All of them
were found as slightly submerged in soft mud at TC2, while no horseshoe crab
was found in TC1, TC3 and ST. Since all found target fauna were large
individuals (prosomal width >100mm), their records are excluded from the
data analysis to avoid mixing up with juvenile population living on intertidal
habitat. Photo records of the observed horseshoe crab are shown in Figure 3.1 of Appendix Iand 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.
6.5.23
individuals of Carcinoscorpiusrotundicauda
with average body size 270mm were found in TC2. Although the searching rate was
low (0.75 ind. hr-1 person-1) for TC2, it made great
participation of horseshoe crab searching in this sampling zone due to the low
search record in previous monitoring. 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.
6.5.3Two of the observed horseshoe crabs were a mating pair with large body
sizes (prosomal width: Male 280mm; Female 310mm), which were nearly burrowing
in soft mud at low tidal level (0.5- 1.0m above C.D.) (Figure 3.2 of Appendix I). The mating pair indicated the breeding
of horseshoe crab could be possible along the coast of Tung Chung Wan, as long
as suitable substratum was available. It is estimated the searching rate will
be higher in next survey (June.2019), due to the warmer and more humid weather
in following months (April – September). The suitable breeding period of target
fauna is believed in wet season, more mating pairs and the tiny individuals
(i.e. newly hatched) were usually recorded in June and September every year (Figure 3.3 of Appendix I).
6.5.4Despite of mating pair, a large individual (Prosomal width: 290mm) was
found in TC2 (Figure 3.4 of Appendix I).
Based on its size, 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. This large individual might move onto intertidal
shore occasionally during high tide for foraging and breeding. Because it
should be inhabiting sub-tidal habitat most of the time. This record is
excluded from the data analysis to avoid mixing up with juvenile population
living on intertidal habitat. The searching record of the horseshoe individual
is estimated to increase in next survey (June 2019), since the horseshoe crab
activity would increase gradually with the warmer weather instead of being
inactive and burrowed in sediments.
6.5.5No marked individual of horseshoe crab was
recorded in the present survey. Some marked individuals were found n 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.
6.5.6The 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
6.5.7In present survey, only 3 individuals
of horseshoe crab were observed in TC2 while no target
fauna was found in ST, TC1 and TC3. Although there were horseshoe crabs found
in TC2, all of them were large individuals which are excluded from the
analysis. The search record for each sampling zone was 0 ind. hr-1person-1.
Figure 3.5of Appendix
I and 3.6of Appendix I show the changes of number of individuals, mean
prosomal width and search record of horseshoe crabsCarcinoscorpiusrotundicaudaand Tachypleustridentatusinrespectively in each sampling zone
throughout the monitoring period.
6.5.8To consider the entire monitoring
period for TC3 and ST, medium to high search records (i.e. number of
individuals) of both species (Carcinoscorpiusrotundicauda and Tachypleustridentatusin) 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 Carcinoscorpiusrotundicauda
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 Carcinoscorpiusrotundicauda
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 Tachypleustridentatus was observed in TC3.
6.5.9For TC1, the search record was at
low to moderate level throughout the monitoring period. The change of Carcinoscorpiusrotundicauda
was relatively more variable than that of Tachypleustridentatus. 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.
Seasonal
variation of horseshoe crab population
6.5.10Throughout
the monitoring period, the search records of horseshoe crabs were fluctuated
and at moderate – very low level in March (Figures
3.5 and 3.6 of Appendix I). Low – Very low search record was found in March
2013, totally 17 ind. of Tachypleustridentatus
and 0 ind. of Carcinoscorpiusrotundicauda
were found in TC1, TC3 and ST. Compare with the search record of Mar 2013, the
numbers of Tachypleustridentatus
were increased by more than 2 times in March 2014 and 2015 (46 ind. in 2014 and
45 ind. in 2015); the number of Carcinoscorpiusrotundicauda raise to 20 and 60 ind. in March 2014 and
2015 respectively. In March 2016, the search record dropped obviously. Only 1
and 23 ind. of Tachypleustridentatus
and Carcinoscorpiusrotundicauda
were found, respectively. Then, the search records rise again in March 2017 and
March 2018. The number of Tachypleustridentatus was increased to 14 and 44 ind., while that
of Carcinoscorpiusrotundicauda rise
again to 33 and 31 ind. in March 2017 and 2018, respectively. 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, while
occasional records of 1 to 3 individuals in TC1 and TC2 found. In March 2019, 3
ind.ofCarcinoscorpiusrotundicauda 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.
6.5.11The 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
– low search record was found in December from 2012 to 2015 (0-4 ind. of Carcinoscorpiusrotundicauda
and 0-12 ind. of Tachypleustridentatus). The horseshoe crabs were inactive and
burrowed in the sediments during cold weather (<15 ºC). Similar results of
low search record in dry season were reported in a previous territory-wide
survey of horseshoe crab. For example, the search records in Tung Chung Wan
were 0.17 ind. hr-1 person-1 and 0.00 ind. hr-1 person-1 in wet season and dry
season respectively (details see Li, 2008). 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 Carcinoscorpiusrotundicauda and 24 individuals of Tachypleustridentatus
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�aC 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.
6.5.12From September 2012 to December
2013, Carcinoscorpiusrotundicauda
was less common species relative to Tachypleustridentatus. 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).
6.5.13For Tachypleustridentatus, 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 Tachypleustridentatus
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 Tachypleustridentatus
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.
6.5.14Recently, Carcinoscorpiusrotundicauda
was a more common horseshoe crab species in Tung Chung Wan. It was recorded in
the four sampling zones while the majority of population located in TC3 and ST.
Due to potential breeding last year, Tachypleustridentatusbecame common again and distributed in TC3
and ST mainly. 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
6.5.15Figure 3.7 of Appendix I shows the changes of prosomal width of Carcinoscorpiusrotundicauda
and Tachypleustridentatus
in TC3. As mentioned above, Carcinoscorpiusrotundicauda 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 40-60 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
60-90 mm) along the sampling months. Juveniles reaching this size might
gradually migrate to sub-tidal habitats.
6.5.16For Tachypleustridentatus,
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
25-35 mm to 35-65 mm. As mentioned, the large individuals might have reached a
suitable size for migrating from the nursery soft shore to subtidal habitat. It
accounted for the declined population in TC3. From 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
60-80 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
6.5.17Figure 3.8 of Appendix I shows the changes of prosomal width of Carcinoscorpiusrotundicauda
and Tachypleustridentatus
in ST. As mentioned above, Carcinoscorpiusrotundicauda 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
60-80 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.
6.5.18For Tachypleustridentatus,
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 60-70 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 40-60 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
individuals was very few in ST that no box plot could be produced. In June
2016, the prosomal width of major population ranged 50-70 mm. But it dropped
clearly to 30-40 mm in September 2016 followed by an increase to 40-50 mm in
December 2016, 40-70 mm in March 2017 and 50-60mm 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 40-50 mm to 45-60 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 60-80 mm in prosomal width. Juveniles reaching this
size would gradually migrate to sub-tidal habitats.
6.5.19As a summary for horseshoe crab
populations in TC3 and ST, there were spawning of Carcinoscorpiusrotundicauda
from 2014 to 2018 while the spawning time should be in spring. The population
size was consistent in these two sampling zones. For Tachypleustridentatus, 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.
6.5.20Although
no horseshoe crab was recorded in TC3 and ST in March 2019, it was the first
monitoring of 2019. The search record of horseshoe crab was usually fluctuated
and influenced by weather condition and tidal level. Overall population growth
of horseshoe crab in 2019 should be evaluated from the results of the following
surveys as well, while it is estimated to maintain a moderate level as 2018.
Impact of the HKLR project
6.5.21It was
the 26th 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
6.5.22Only seagrass species Halophila ovalis was found in present
survey, which was found in ST. There were one medium -large sized and three
smalls sized of seagrass bed. The largest rand had area ~1000m2 in
medium vegetation coverage (50-60%) and located at tidal zone 1.5- 2.0 m above
C.D nearby mangroves plantation. At close vicinity, three smalls sized of Halophila ovalis beds with area ~ 1 m2
were observed. Two of them were in high vegetation coverage (90-100%) and the
remaining one was in medium vegetation coverage (50-60%). 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.
6.5.23Since 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 0.5-2.0
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.
6.5.24According 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
Figure 3.11 of Appendix Ishows 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 March 2019 (present
survey) while no patch of Zostera
japonica was found.
6.5.25For Halophila ovalis, it was recorded
as 3-4 medium to large patches (area 18.9-251.7 m2; vegetation
coverage 50-80%) beside the mangrove vegetation at tidal level 2 m above C.D.
in 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 1-72 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 3-4small to large
patches (6-253 m2) at high tidal level and 1large 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 21st September
2014. The strong water current caused by the cyclone, Kalmaegi
especially, might have given damage to the seagrass beds. In addition, natural
heat stress and grazing force were other possible causes reducing seagrass beds
area. Besides, very small patches of Halophila ovalis could be found in other
mud flat area in addition to the recorded patches. But it was hardly
distinguished due to very low coverage (10-20%) and small leaves.
6.5.26In 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
6.5.27Typhoon 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.
6.5.28Prolonged
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 (Long staff and Dennison, 1999).
6.5.29In order to investigate any deterioration of
water quality (e.g. more turbid) in ST, the water quality measurement results at
two closest monitoring stations SR3 and IS5 of the EM&A programme
were obtained from the water quality monitoring team. Based on the results from
June to December 2014, the overall water quality was in normal fluctuation
except there was one exceedance of suspended solids (SS) at both stations in
September. On 10th 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 station’s reading)
and Limit Level (≤34.4 mg/L and 130% of upstream control station’s reading)
respectively. The turbidity readings at SR3 and IS5 reached 24.8-25.3 NTU and
22.3-22.5 NTU respectively. The temporary turbid water should not be caused by
the runoff from upstream rivers. Because there was no rain or slight rain from
1st to 10th 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 ‘Notifications of Environmental Quality Limits Exceedances’ provided by
the respective environmental team. The respective construction of seawall and
stone column works, which possibly caused turbid water, 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.
6.5.30Based 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 (Vermaatet al., 1995). Previous studies showed that the seagrass bed could
be recovered to the original sizes in 2 months through vegetative propagation
after experimental clearance (Supanwanid, 1996).
Moreover it was reported to recover rapidly in less than 20 days after dugong
herbivory (Nakaoka and Aioi,
1999).As mentioned, the disappeared seagrass in ST in 1995 could recover
gradually after the completion of reclamation works for international airport
(Fong, 1998).The seagrass beds of 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
6.5.31Figure 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 bed 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
6.5.32In 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.
6.5.33Between 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
in22-23rd, 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.
6.5.34According 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.
6.5.35Overall, 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).
In March 2019 (present survey), the seagrass bed area increased again.
Relatively, it would occur later and slower than the previous round (more than
2 years).
Impact of the HKLR
project
6.5.36It was the 26th 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 is recolonizing since there has been a gradual increase in the
size and number of that after the hit of the super cyclone in September 2018.
Intertidal Soft Shore Communities
6.5.37Substratum
6.5.38Table 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:
·In TC1, high percentages of ‘Gravels
and Boulders’(H: 70%; M: 60%) were
recorded at high and mid tidal levels. Relatively higher percentages of ‘Gravels
and Boulders’ (40%) and ‘Soft
mud’ (40%) were
recorded at low tidal level.
·In TC2, higher percentage of ‘Sands’ (50%) was recorded at high tidal level. At
mid tidal level, there was higher percentage of ‘Soft mud’ (50%) followed by ‘Gravels
and Boulders’ (30%). At
low tidal level, the major substratum type was 'Soft mud' (60%).
·In TC3, higher percentage of ‘Sands’ (60%) was recorded followed by ‘Soft
mud’ (30%) at
high tidal level. At mid tidal level, higher percentages of ‘Soft mud’ (70%)
and ‘Sands’ (30%) were recorded. At low tidal level, the
main substratum type was ‘Gravels and
Boulders’ (80%).
·In ST, ‘Gravels
and Boulders’ was the
main substratum type (100%) at high tidal level. At mid tidal level, there were
even distributions of ‘Gravels and Boulders’ (50%) and
‘Sands’ (50%). At low
tidal level, ‘Sands’ was the main substratum type
(70%).
6.5.39There 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
6.5.40Table 3.4 of Appendix I lists the total abundance, density and
number of taxon of every phylum in this survey. A total
of 14803 individuals were recorded. Mollusca was the most abundant phylum
(total abundance 13903 ind, density 463 ind. m-2,
relative abundance 93.9%). The second and third abundant phya
were Arthropoda (698 ind., 23 ind. m-2, 4.7%) and Annelida (128 ind.,
4 ind. m-2, 0.9%) respectively. Relatively other phyla were very low
in abundances (density £1 ind. m-2, relative abundance £0.3%). Moreover, the most diverse
phylum was Mollusca (46 taxa) followed by Annelida (9 taxa) and Arthropoda (6
taxa). There was 1 taxa recorded only for other phyla.
6.5.41The 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:
·Cerithideacingulata was revised as Pirenellaasiatica
·Cerithideadjadjariensis was revised as Pirenellaincisa
·Cerithidearhizophorarum was revised as Cerithideamoerchii
Moreover, taxonomic revision was conducted on another snail species
while the specie name was revised:
·Batillariabornii was revised as Clypeomorusbifasciata
6.5.42Table 3.5 of Appendix I shows the number of individual, relative
abundance and density of each phylum in every sampling zone. The total
abundance (3268- 4322 ind.) varied among the four sampling zones while the phyla
distributions were similar. In general, Mollusca was the most dominant phylum
(no. of individuals: 3037-4119 ind.; relative abundance 92.4-95.3%; density
416-549 ind. m-2). Other phyla were much lower in number of
individuals. Arthropoda (78-255 ind.; 2.4-6.5 %; 10-34 ind. m-2) and
Annelida (11-81 ind.; 0.3-2.5 %; 1-11 ind. m-2) were common phyla
relatively. Other phyla were very low in abundance in all sampling zones.
Dominant species in every sampling zone
6.5.43Table 3.6 of Appendix I lists the abundant species (relative
abundance >10%) in every sampling zone. In the present survey, most of the
listed abundant species were of low to moderate densities (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.
6.5.44In TC1, the substratum was mainly ‘Gravels and Boulders’ at high and mid
tidal levels. The high tidal level was clearly dominated by rock oyster Saccostrea cucullata
(190 ind. m-2, relative abundance 37%) at high density followed by
gastropod Monodontalabio (61
ind. m-2, 12%). At mid tidal level, rock oyster Saccostrea cucullata (108 ind. m-2,
22%), Monodontalabio (74
ind. m-2, 15%) and Batillariamultiformis (63 ind. m-2, 13%) were abundant
at low - moderate densities. At low tidal level (main substratum types ‘Gravels
and Boulders’ or ‘Soft mud’), rock oyster Saccostrea
cucullata (146 ind. m-2, 26 %) was
more abundant at moderate density and gastropods Lunella coronate (81ind. m-2, 15%) was found at low-moderate
densities.
6.5.45In TC2, the substratum types were mainly 'Sands' at high tidal level.
Gastropods Pirenellaincisa (102
ind. m-2, 21 %) was abundant at moderate density. Rock oyster Saccostrea cucullata
(87 ind. m-2, 18 % attached on boulder), Pirenellaasiatica (74 ind. m-2, 16%)
and Monodontalabio (66
ind. m-2, 14%) were abundant at low-moderate densities. At mid tidal
level (main substratum type ‘Soft mud’), gastropods Pirenellaincisa (81 ind. m-2, 19 %)
and Rock oyster Saccostrea cucullata (74 ind. m-2, 17%) were abundant
at low- moderate density. At low tidal level (main substratum type ‘Soft mud’),
Rock Oyster Saccostrea cucullata (99 ind. m-2, 34%) was abundant at
moderate density and followed by gastropod Monodontalabio (42 ind. m-2, 10 %) at
low- moderate density.
6.5.46In TC3, the
substratum types were either ‘Sands’ or ‘Soft mud’ at high and mid tidal
levels. At high tidal level, Rock oyster Saccostrea cucullata
(111 ind. m-2, 20%) was dominant followed by gastropods Batillariamultiformis
(87 ind. m-2, 16%) and Monodontalabio (55 ind. m-2, 10%) at
low-moderate densities. At mid tidal level, Rock oyster Saccostrea cucullata (118 ind. m-2, 17%) was dominant
followed by gastropods Batillariazonalis (111 ind. m-2, 16%) and Batillariamultiformis
(88 ind. m-2, 12%) at low-moderate densities .At low tidal level
(major substratum: ‘Gravels and Boulders’), rock oyster Saccostrea cucullata (135 ind. m-2, 28 %, attached on
boulders) was dominant at moderate density and followed by gastropod Pirenellaincisa
(70 ind. m-2, 15 %) and Lunella
coronate (50 ind. m-2, 10%) were abundant at low-moderate
densities.
6.5.47In ST, the major substratum type was ‘Gravels and Boulders’ at high
tidal level. At high tidal level, Rock oyster Saccostrea cucullata (147 ind. m-2,
31%) was dominant at high density and followed by gastropods Batillariamultiformis
(117 ind. m-2, 24%) were dominant at moderate densities.Batillariazonalis (61 ind. m-2, 13%) was abundant at
low-moderate density. At mid tidal level (even distribution of ‘Gravals
and Boulders’ and ‘Sand’), Rock
oyster Saccostrea cucullata(165 ind. m-2, 30%) was dominant
at high density and followed by gastropods Batillariazonalis(85
ind. m-2, 15%),Pirenellaincisa (78 ind. m-2, 14 %) and Batillariamultiformis
(66 ind. m-2, 12%) at low-moderate densities. At low tidal level (major substratum:
‘Sands’), rock oyster Saccostrea cucullata(90 ind. m-2, 32 %, attached on boulders) was dominant at
moderate density and followed by gastropodPirenellaincisa
(50 ind. m-2, 18 %) at low-moderate densities.
6.5.48In 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 cucullata (847 ind.),
gastropods Batillariamultiformis
(246 ind.), Batillariazonalis (146
ind.), Monodontalabio (135
ind.), Pirenella incise (128 ind.) and Lunella coronate (81 ind.) were the most common
species on gravel and boulders substratum. Rock oyster Saccostrea cucullata (624 ind.), Pirenellaasiatica (226
ind.), Batillariamultiformis
(176 ind.), Monodontalabio (162
ind.), Batillariazonalis (111
ind.), Pirenella incise (102 ind.) and Lunella coronate (50 ind.) were the most common
species on sandy and soft mud substrata.
Biodiversity and abundance of soft shore communities
6.5.49Table 3.7 of Appendix I shows
the mean values of species number, density, biodiversity index H’ and species
evenness J of soft shore communities at every tidal level and in every sampling
zone. As mentioned above, the differences among sampling zones and tidal levels
were determined by the major type of substratum primarily.
6.5.50Among the sampling zones, the
mean species number was similar (7-12 spp. 0.25 m-2) among the four sampling
zones. The mean densities of TC1 and TC3 (524 and 572 ind. m-2) were
higher than ST (438 ind. m-2) followed by TC2 (436 ind. m-2).
The higher densities of TC1 and TC3 are due to the relatively high number of
individuals in each quatrat. Moreover, TC1 and TC3
was relatively higher in H' (2.0) and J (0.8) due to higher species number and
even taxa distribution. Lower H’ (1.6) was resulted in TC1, which was due to
the lower species number. The value of J at TC2 was 0.8, which was similar to
that of TC1 and TC3. In ST, higher densities were mainly accounted by 1-2
abundant gastropods. It resulted in lower H’ (1.4) and J (TC2: 0.7).
6.5.51In the present survey, no clear
trend of mean species number, mean density, H’ and J observed among the tidal
level.
6.5.52Figures 3.14 to 3.17 of Appendix I show the temporal changes of mean species number, mean density, H’ and
J at every tidal level and in every sampling zone along the sampling months. In
general, all the biological parameters fluctuated seasonally throughout the
monitoring period. Lower mean species number and density were recorded in dry
season (December) but the mean H' and J fluctuated within a limited range.
6.5.53From 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 March 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
6.5.54It was
the 26th 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.
6.6.1AFCD, 2018. Potamidid
Snails in Hong Kong Mangrove. Agriculture, Fisheries and Conservation
Department Newsletter - Hong Kong Biodiversity Issue #25, 2-11
6.6.2Chan,
K.K., Caley, K.J., 2003. Sandy Shores, Hong Kong Field Guides 4. The Department
of Ecology & Biodiversity, The University of Hong Kong. pp 117.
6.6.3Dai,
A.Y., Yang, S.L., 1991. Crabs of the China Seas. China Ocean Press. Beijing.
6.6.4Dong,
Y.M., 1991. Fauna of ZheJiang Crustacea. Zhejiang
Science and Technology Publishing House. ZheJiang.
6.6.5EPD,
1997. Technical Memorandum on Environmental Impact Assessment Process (1st
edition). Environmental Protection Department, HKSAR Government.
6.6.6Fauchald, K., 1977. The polychaete
worms. Definitions and keys to the orders, families and genera. Natural History
Museum of Los Angeles County, Science Series 28. Los Angeles, U.S.A..
6.6.7Fong,
C.W., 1998. Distribution of Hong Kong seagrasses. In: Porcupine! No. 18. The
School of Biological Sciences, The University of Hong Kong, in collaboration
with Kadoorie Farm & Botanic Garden Fauna
Conservation Department, p10-12.
6.6.8Li,
H.Y., 2008. The Conservation of Horseshoe Crabs in Hong Kong. MPhil Thesis,
City University of Hong Kong, pp 277.
6.6.9Longstaff,
B.J., Dennison, W.C., 1999. Seagrass survival during pulsed turbidity events:
the effects of light deprivation on the seagrasses Halodulepinifolia and Halophila
ovalis. Aquatic Botany 65 (1-4), 105-121.
6.6.10Longstaff,
B.J., Loneragan, N.R., O’Donohue,
M.J., Dennison, W.C., 1999. Effects of light deprivation on the survival and recovery
of the seagrass Halophila ovalis (R.
Br.) Hook. Journal of Experimental Marine Biology and Ecology 234 (1), 1-27.
6.6.11Nakaoka, M., Aioi, K.,
1999. Growth of seagrass Halophila ovalis
at dugong trails compared to existing within-patch variation in a Thailand
intertidal flat. Marine Ecology Progress Series 184, 97-103.
6.6.12Pielou, E.C., 1966. Shannon’s formula as a measure
of species diversity: its use and misuse. American Naturalist 100, 463-465.
6.6.13Qi,
Z.Y., 2004. Seashells of China. China Ocean Press. Beijing, China.
6.6.14Qin,
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.
6.6.15Shannon,
C.E., Weaver, W., 1963. The Mathematical Theory of Communication. Urbana:
University of Illinois Press, USA.
6.6.16Shin,
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.
6.6.17Supanwanid, 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.
6.6.18Vermaat, 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.
6.6.19Yang,
D.J, Sun, R.P., 1988. Polychaetous annelids commonly
seen from the Chinese waters (Chinese version). China Agriculture Press, China
7.1.1Site Inspections were carried out on a weekly basis to monitor the
implementation of proper environmental pollution control and mitigation
measures for the Project. During the reporting month, five site inspections
were carried out on 1, 6, 13, 20 and
29 March 2019.
7.1.2A summary of
observations found during the site inspections and the follow up actions taken by the
Contractor are described in Table
7.1.
Table 7.1Summary
of Environmental Site Inspections
Date of Audit
Observations
Actions Taken by Contractor / Recommendation
Date of Observations Closed
22 Feb 2019
1.The NRMM label of a generator was missing
at LCSD Depot.
2.Waste was scattered on the ground at LCSD
Depot.
3.Waste was accumulated on the ground at N4.
1.NRMM
label was provided on the generator at LCSD Depot.
2.The
waste was removed from LCSD Depot.
3.The
waste was removed from N4.
1 Mar 2019
1 Mar 2019
1.Waste was observed at N13A.
2.Stagnant water was observed at N4.
3.Waste
was observed on the ground at LCSD Depot.
1.The waste was removed from N13A.
2.The stagnant water was removed from N4.
3.The
waste was removed from LCSD Depot.
6 Mar 2019
6 Mar 2019
1.Waste
was accumulated at LCSD Depot.
2.An
unused chemical container was observed without drip tray at N4.
3.Waste was accumulated at S7.
1.The
waste was removed from LCSD Depot.
2.The
unused chemical container was removed from N4.
3.The
waste was removed from S7.
13 Mar 2019
13 Mar 2019
1.Waste was accumulated at LCSD Depot.
2.Waste was observed at N4.
3.Waste was observed at S28.
1.The
waste was removed from LCSD Depot.
2.The
waste was removed from N4.
3.The
waste was removed from S28.
20 Mar 2019
20 Mar 2019
1.Waste was observed at S28.
2.Oil stain was observed at N13A.
3.Waste was observed at N4.
1.The waste was removed from S28.
2.The oil stain was removed from N13A.
3.The
waste was removed from N4.
29 Mar 2019
29 Mar 2019
1.Waste was observed at S16.
2.Waste was observed at N4.
3.Chemical container without drip tray was
observed at LCSD Depot.
The Contractor was recommended to:
1.remove the waste from S16.
2.remove the waste at N4.
3.provide drip tray for the chemical
container remove the waste from LSCD Depot.
Follow-up
actions for the observations issued for the last weekly site inspection of the reporting
month will be inspected during the next site inspection.
7.1.3The Contractor has
rectified most of the observations as identified during environmental site inspections
within the reporting month. Follow-up actions for outstanding observations will
be inspected during the next site inspection.
7.2Advice on the
Solid and Liquid Waste Management Status
7.2.1The Contractor
registered as a chemical waste producer for the Contract. Sufficient numbers of
receptacles were available for general refuse collection and sorting.
7.2.2Monthly summary of waste flow table is detailed in Appendix J.
7.2.3The Contractor was reminded that
chemical waste containers should be properly treated and stored temporarily in
designated chemical waste storage area on site in accordance with the Code of
Practice on the Packaging, Labelling and Storage of Chemical Wastes.
7.3.1The valid
environmental licenses and permits during the reporting month are summarized in
Appendix L.
7.4Implementation Status of Environmental Mitigation
Measures
7.4.1In response to the
site audit findings, the Contractors have rectified most of theobservations as identified during environmental site
inspections during the reporting month. Follow-up actions for outstanding
observations will be inspected during the next site inspections.
7.4.2A summary of the
Implementation Schedule of Environmental Mitigation Measures (EMIS) is
presented in Appendix M. Most of the
necessary mitigation measures were implemented properly.
7.4.3Regular marine travel route for
marine vessels were implemented properly in accordance to the submitted plan
and relevant records were kept properly.
7.4.4Dolphin Watching Plan was
implemented during the reporting month. No dolphins inside the silt curtain
were observed. The relevant records were kept properly.
7.5.1For 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.
7.5.2For construction noise, no Action
and Limit Level exceedances were recorded at station NMS5 during the reporting
month.
7.5.3For marine
water quality monitoring, no Action Level and Limit Level exceedances of
dissolved oxygen level and turbidity level were recorded during the reporting
month. Also, no Limit Level exceedances of
suspended solids level were recorded. Two Action Level exceedances of suspended
solids level were recorded during the reporting month. The
exceedances were considered as non-contract related
7.6Summary of
Complaints, Notification of Summons and Successful Prosecution
7.6.1There was no complaint received in relation to the environmental impacts
during this reporting month.
7.6.2The details of cumulative statistics of Environmental Complaints are provided in Appendix K.
7.6.3No notification of summons and
prosecution was received during the reporting period. Statistics on
notifications of summons and successful prosecutions are summarized in Appendix N.
9.1.1The construction phase and EM&A programme of the
Contract commenced on 17 October 2012. This is the seventy-eighth Monthly EM&A report for the
Contract which summarizes the monitoring results and audit findings of the
EM&A programme during the reporting period from 1
to 31 March 2019.
Air Quality
9.1.2For 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
9.1.3For construction
noise, no Action and Limit Level exceedances were recorded at station NMS5
during the reporting month.
Water Quality
9.1.4For marine water quality monitoring, no Action Level
and Limit Level exceedances of dissolved oxygen level and turbidity level were
recorded during the reporting month. Also, no Limit Level exceedances of
suspended solids level were recorded. Two Action Level exceedances of suspended
solids level were recorded during the reporting month. The exceedances were considered as non-contract related
Dolphin
9.1.5During the March’s surveys of the Chinese White Dolphin, no adverse
impact from the activities of this construction project on Chinese White Dolphins was noticeable
from general observations.
9.1.6Due to monthly variation in
dolphin occurrence within the study area, it would be more appropriate to draw
conclusion on whether any impacts on dolphins have been detected related to the
construction activities of this project in the quarterly EM&A report, where
comparison on distribution, group size and encounter rates of dolphins between
the quarterly impact monitoring period (March 2019 – May 2019) and baseline monitoring period
(3-month period) will be made.
Mudflat
9.1.7This measurement result was
generally and relatively higher than the baseline measurement at S1, S2, S3 and
S4. The mudflat level is continuously increased.
9.1.9Environmental site inspections were carried out on 1, 6, 13, 20 and 29 March 2019. Recommendations on remedial actions were given to the
Contractors for the deficiencies identified during the site inspections.
9.1.10There 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.