Executive
Summary
The Hong Kong-Zhuhai-Macao
Bridge (HZMB) Hong Kong Link Road (HKLR) serves to connect the HZMB Main Bridge
at the Hong Kong Special Administrative Region (HKSAR) Boundary and the HZMB
Hong Kong Boundary Crossing Facilities (HKBCF) located at the north eastern
waters of the Hong Kong International Airport (HKIA).
The HKLR project has been
separated into two contracts. They are Contract No. HY/2011/03 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between Scenic Hill and
Hong Kong Boundary Crossing Facilities (hereafter referred to as the Contract)
and Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road-Section between HKSAR Boundary and Scenic Hill.
China State Construction
Engineering (Hong Kong) Ltd. was awarded by Highways Department as the
Contractor to undertake the construction works of Contract No. HY/2011/03. The main works of the Contract include
land tunnel at Scenic Hill, tunnel underneath Airport Road and Airport Express
Line, reclamation and tunnel to the east coast of the Airport Island, at-grade
road connecting to the HKBCF and highway works of the HKBCF within the Airport
Island and in the vicinity of the HKLR reclamation. The Contract is part of the HKLR Project
and HKBCF Project, these projects are considered to be ¡§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.
BMT Asia Pacific Limited
has been appointed by the Contractor to implement the Environmental Monitoring
& Audit (EM&A) programme for the Contract in accordance with the
Updated EM&A Manual for HKLR (Version 1.0) and will be providing
environmental team services to the Contract.
This is the fifty-seventh Monthly EM&A report for the Contract which
summarizes the monitoring results and audit findings of the EM&A programme
during the reporting period from 1 to 30 June 2017.
Environmental
Monitoring and Audit Progress
The monthly EM&A programme
was undertaken in accordance with the Updated EM&A Manual for HKLR (Version
1.0). A summary of the monitoring
activities during this reporting month is listed below:
1-hr TSP
Monitoring
|
1, 7, 13, 19, 23 and 29 June 2017
|
24-hr TSP
Monitoring
|
6, 12, 17, 22, 28 and 29 June 2017
|
Noise
Monitoring
|
1, 7, 15, 19 and 29 June 2017
|
Mudflat Monitoring (Mudflat)
|
2, 3, 9, 10 and 11 June 2017
|
Mudflat Monitoring (Sedimentation Rate)
|
8 June 2017
|
Chinese White
Dolphin Monitoring
|
14, 15, 20 and
26 June 2017
|
Site
Inspection
|
1, 7, 14, 21
and 30 June 2017
|
Due
to power supply failure, the 24-hour TSP monitoring at AMS5 was rescheduled
from 28 June 2017 to 29 June 2017.
Due
to weather condition, the noise monitoring schedule was rescheduled from 13
June 2017 to 15 June 2017.
The
monitoirng schedule of water quality monitoring for all stations except station
CS2 were adopted from the published Monthly Environmental Monitoring and Audit
(EM&A) Report for June 2017 prepared for Contract No. HY/2010/02 Hong
Kong-Zhuhai-Macao Bridge Hong Kong Boundary Crossing Facilities ¡V Reclamation
Works. The monitoirng schedule of water quality monitoring for station CS2 was
adopted from the published Monthly EM&A Report for June 2017 prepared by
Contract No. HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road ¡V
Section between HKSAR Boundary and Scenic Hill.
Due
to suitable weather and ambient temperature, the mudflat monitoring was
rescheduled from 12 June 2017 to 2 and 3 June 2017.
Due
to weather condition, the dolphin monitoring schedule was rescheduled from 19
June 2017 to 20 June 2017.
Breaches of Action and Limit Levels
A summary of environmental
exceedances for this reporting month is as follows:
Environmental Monitoring
|
Parameters
|
Action Level (AL)
|
Limit Level (LL)
|
Air Quality
|
1-hr TSP
|
0
|
0
|
24-hr TSP
|
0
|
0
|
Noise
|
Leq (30 min)
|
0
|
0
|
Water Quality
|
Suspended solids level (SS)
|
0
|
0
|
Turbidity level
|
0
|
0
|
Dissolved oxygen level (DO)
|
0
|
0
|
Complaint
Log
For Environmental Complaint
No. COM-2017-095(3) mentioned in previously Monthly EM&A Report for May
2017, it was considered that the complaint was likely related to Contract No. HY/2011/03.
The Contractor has implemented the following measures to minimize the potential
noise impact:
- Additional
noise barriers have been erected in the active working area to further mitigate
the associated noise emissions as far as practicable;
-
Cover
the breaker tip with acoustic material;
-
Noise
barriers have been located as close as possible to the noise source. Also, gaps
and openings at joints in the barriers material have been minimized;
-
Speed
up of construction works in order to shorten the duration noise impact/nuisance
to the surrounding;
-
Minimize
the quantities of noisy plant as far as practicable; and
-
Regular
review of working duration and switch off all unnecessary machinery and plant.
There was no complaint
received in relation to the environmental impacts during the reporting period.
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.
Technical issues had been observed from impact
monitoirng of the Contract and thus published information from Monthly EM&A Report for June 2017 prepared for Contract No. HY/2010/02 and
Contract No. HY/2011/09 were adopted for the Contract.
Future
Key Issues
The future key issues include
potential noise, air quality, water quality and ecological impacts and waste
management arising from the following construction activities to be undertaken
in the upcoming month:
¡P
Stockpiling at WA7;
¡P
Removal of toe loading at Portion X;
- Dismantling/trimming
of Temporary 40mm Stone Platform for Construction of Seawall at Portion X;
- Construction of
Seawall at Portion X;
- Loading and Unloading
Filling Materials at Portion X;
- Backfilling at Scenic
Hill Tunnel (Cut & Cover Tunnel) at Portion X;
- Excavation for HKBCF
to Airport Tunnel & Construction of Tunnel Box Structure at Portion X;
- Excavation for
Diversion of Culvert PR14 at Portion X;
¡P
Works for Diversion of Airport Road;
- Utilities Detection at
Airport Road / Airport Express Line/ East Coast Road;
- Establishment of Site
Access at Airport Road / Airport Express Line/East Coast Road;
¡P
Construction
of Tunnel Box Structure at Shaft 3 Extension North Shaft;
- Excavation and Lateral
Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel West (Cut & Cover Tunnel) at Airport Road;
- Excavation and Lateral
Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel East (Cut & Cover Tunnel) at Portion X;
- Sub-structure &
Superstructure Works for Highway Operation and Maintenance Area Building
at Portion X; and
¡P
Superstructure Works for Scenic Hill
Tunnel West Portal Ventilation building at West Portal.
1.1.2
The
HKLR project has been separated into two contracts. They are Contract No. HY/2011/03 Hong Kong-Zhuhai-Macao
Bridge Hong Kong Link Road-Section between Scenic Hill and Hong Kong Boundary
Crossing Facilities (hereafter referred to as the Contract) and Contract No.
HY/2011/09 Hong Kong-Zhuhai-Macao Bridge Hong Kong Link Road-Section between
HKSAR Boundary and Scenic Hill.
1.1.3
China
State Construction Engineering (Hong Kong) Ltd. was awarded by Highways Department (HyD) as
the Contractor to undertake the construction works of Contract No.
HY/2011/03. The Contract is part of
the HKLR Project and HKBCF Project, these projects are considered to be
¡§Designated Projects¡¨, under Schedule 2 of the Environmental Impact Assessment
(EIA) Ordinance (Cap 499) and Environmental Impact Assessment (EIA) Reports
(Register No. AEIAR-144/2009 and AEIAR-145/2009) were prepared for the
Project. The current Environmental
Permit (EP) EP-352/2009/D for HKLR and EP-353/2009/K for HKBCF were issued on
22 December 2014 and 11 April 2016, respectively. These documents are available
through the EIA Ordinance Register. The construction phase of
Contract was commenced on 17 October 2012.
Figure
1.1
shows the project site boundary. The works areas are shown in Appendix O.
1.1.4
The Contract includes the
following key aspects:
¡P
New reclamation along the east coast
of the approximately 23 hectares.
¡P
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.
¡P
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.
¡P
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.
¡P
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.
¡P
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.
¡P
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.
1.1.6 BMT Asia Pacific Limited has been appointed
by the Contractor to implement the EM&A programme for the Contract in
accordance with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and
will be providing environmental team services to the Contract. Ramboll Environ Hong Kong Ltd. was employed by
HyD as the Independent Environmental Checker (IEC) and Environmental Project
Office (ENPO) for the Project. The project organization
with regard to the environmental works is as follows.
1.2.1
The project organization
structure and lines of communication with respect to the on-site environmental
management structure is shown in Appendix A. The key personnel contact names and
numbers are summarized in Table 1.1.
Table 1.1 Contact
Information of Key Personnel
Party
|
Position
|
Name
|
Telephone
|
Fax
|
Supervising Officer¡¦s Representative
(Ove Arup & Partners Hong
Kong Limited)
|
(Chief
Resident Engineer, CRE)
|
Robert Antony
Evans
|
3968 0801
|
2109 1882
|
Environmental Project Office /
Independent Environmental Checker
(Ramboll Environ Hong Kong Limited)
|
Environmental Project Office Leader
|
Y. H. Hui
|
3465
2888
|
3465
2899
|
Independent Environmental Checker
|
Antony Wong
|
3465
2888
|
3465
2899
|
Contractor
(China State Construction Engineering (Hong Kong) Ltd)
|
Project Manager
|
S. Y. Tse
|
3968
7002
|
2109
2588
|
Environmental Officer
|
Federick Wong
|
3968
7117
|
2109
2588
|
Environmental Team
(BMT Asia Pacific)
|
Environmental Team Leader
|
Claudine Lee
|
2241
9847
|
2815
3377
|
24
hours complaint hotline
|
---
|
---
|
5699
5730
|
---
|
1.3
Construction
Programme
1.3.1
A copy of the Contractor¡¦s
construction programme is provided in Appendix B.
1.4
Construction
Works Undertaken During the Reporting Month
1.4.1 A summary of the construction activities undertaken during this
reporting month is shown in Table 1.2.
Table 1.2 Construction
Activities During Reporting Month
Description of Activities
|
Site Area
|
Stockpiling
|
WA7
|
Dismantling/trimming of temporary 40mm stone platform for construction
of seawall
|
Portion X
|
Construction of seawall
|
Portion X
|
Loading and unloading of filling materials
|
Portion X
|
Backfilling at Scenic Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Excavation for HKBCF to Airport Tunnel &
construction of tunnel box structure
|
Portion X
|
Excavation for diversion of culvert PR14
|
Portion X
|
Works for diversion
|
Airport Road
|
Utilities detection
|
Airport Road/
Airport Express Line/ East Coast Road
|
Establishment of site access
|
Airport Road/
Airport Express Line/ East Coast Road
|
Mined tunnel excavation/ box jacking underneath
Airport Road and Airport Express Line
|
Airport
Road and Airport
Express Line
|
Construction of Tunnel box structure at Package T1.12.1
|
Near Kwo Lo
Wan Road
|
Construction of Tunnel box structure
|
Shaft 3
Extension South & North Shaft
|
Excavation and lateral support works & Construction of Tunnel Box
Structure for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)
|
Airport Road
|
Excavation and lateral support works & construction of tunnel box
structure for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)
|
Portion X
|
Sub-structure & superstructure works for Highway Operation and
Maintenance Area Building
|
Portion X
|
Superstructure works for Scenic Hill Tunnel West Portal Ventilation
building
|
West Portal
|
2.1
Monitoring Requirements
2.1.1
In accordance with the Contract Specific EM&A
Manual, baseline 1-hour and 24-hour TSP levels at two air quality monitoring
stations were established. Impact
1-hour TSP monitoring was conducted for at least three times every 6 days,
while impact 24-hour TSP monitoring was carried out for at least once every 6
days. The Action and Limit Level
for 1-hr TSP and 24-hr TSP are provided in Table
2.1 and Table 2.2, respectively.
Table
2.1 Action
and Limit Levels for 1-hour TSP
Monitoring
Station
|
Action Level,
µg/m3
|
Limit Level,
µg/m3
|
AMS 5 ¡V Ma Wan Chung Village (Tung Chung)
|
352
|
500
|
AMS 6 ¡V Dragonair / CNAC (Group) Building (HKIA)
|
360
|
Table
2.2 Action
and Limit Levels for 24-hour TSP
Monitoring
Station
|
Action Level,
µg/m3
|
Limit Level,
µg/m3
|
AMS 5 ¡V Ma Wan Chung Village (Tung Chung)
|
164
|
260
|
AMS 6 ¡V Dragonair / CNAC (Group) Building (HKIA)
|
173
|
260
|
2.2.1 24-hour
TSP air quality monitoring was performed using High Volume Sampler (HVS)
located at each designated monitoring station. The HVS meets all the
requirements of the Contract Specific EM&A Manual. Portable direct reading dust meters were
used to carry out the 1-hour TSP monitoring. Brand and model of the equipment is
given in Table 2.3.
Table
2.3 Air
Quality Monitoring Equipment
Equipment
|
Brand and
Model
|
Portable direct reading
dust meter (1-hour TSP)
|
Sibata Digital Dust
Monitor (Model No. LD-3B)
|
High Volume Sampler
(24-hour TSP)
|
Tisch Environmental
Mass Flow Controlled Total Suspended Particulate (TSP) High Volume Air
Sampler (Model No. TE-5170)
|
2.3.1 Monitoring
locations AMS5 and AMS6 were set
up at the proposed locations in accordance with Contract Specific EM&A
Manual.
2.3.2
Figure 2.1 shows the locations of monitoring stations. Table 2.4 describes the details of the
monitoring stations.
Table
2.4 Locations
of Impact Air Quality Monitoring Stations
Monitoring Station
|
Location
|
AMS5
|
Ma Wan Chung Village
(Tung Chung)
|
AMS6
|
Dragonair / CNAC
(Group) Building (HKIA)
|
2.4.1 Table 2.5 summarizes the monitoring parameters, frequency
and duration of impact TSP monitoring.
Table
2.5 Air
Quality Monitoring Parameters, Frequency and Duration
Parameter
|
Frequency and Duration
|
1-hour TSP
|
Three times every 6 days while the highest dust
impact was expected
|
24-hour TSP
|
Once every 6 days
|
2.5.1 24-hour
TSP Monitoring.
(a) The HVS was installed in the vicinity of the air
sensitive receivers. The following criteria were considered in the installation
of the HVS.
(i) A horizontal platform with appropriate support to
secure the sampler against gusty wind was provided.
(ii) The distance between the HVS and any obstacles,
such as buildings, was at least twice the height that the obstacle protrudes
above the HVS.
(iii) A minimum of 2 meters separation from walls,
parapets and penthouse for rooftop sampler was provided.
(iv) No furnace or incinerator flues are nearby.
(v) Airflow around the sampler was unrestricted.
(vi) Permission was obtained to set up the samplers and
access to the monitoring stations.
(vii) A secured supply of electricity was obtained to
operate the samplers.
(viii) The sampler was located more than 20 meters from any
dripline.
(ix) Any wire fence and gate, required to protect the
sampler, did not obstruct the monitoring process.
(x) Flow control accuracy was kept within ¡Ó2.5%
deviation over 24-hour sampling period.
(b) Preparation of Filter Papers
(i) Glass fibre filters, G810 were labelled and
sufficient filters that were clean and without pinholes were selected.
(ii) All filters were equilibrated in the conditioning environment
for 24 hours before weighing. The conditioning environment temperature was
around 25 ¢XC and not
variable by more than ¡Ó3 ¢XC;
the relative humidity (RH) was < 50% and not variable by more than ¡Ó5%. A convenient working RH was 40%.
(iii) All filter papers were prepared and analysed by ALS
Technichem (HK) Pty Ltd., which is a HOKLAS accredited laboratory and has
comprehensive quality assurance and quality control programmes.
(c) Field Monitoring
(i) The power supply was checked to ensure the HVS works
properly.
(ii) The filter holder and the area surrounding the
filter were cleaned.
(iii) The filter holder was removed by loosening the four
bolts and a new filter, with stamped number upward, on a supporting screen was
aligned carefully.
(iv) The filter was properly aligned on the screen so
that the gasket formed an airtight seal on the outer edges of the filter.
(v) The swing bolts were fastened to hold the filter
holder down to the frame. The
pressure applied was sufficient to avoid air leakage at the edges.
(vi) Then the shelter lid was closed and was secured
with the aluminium strip.
(vii) The HVS was warmed-up for about 5 minutes to
establish run-temperature conditions.
(viii) A new flow rate record sheet was set into the flow
recorder.
(ix) On site temperature and atmospheric pressure
readings were taken and the flow rate of the HVS was checked and adjusted at
around 1.1 m3/min, and complied with the range specified in the
Updated EM&A Manual for HKLR (Version 1.0) (i.e. 0.6-1.7 m3/min).
(x) The programmable digital timer was set for a
sampling period of 24 hours, and the starting time, weather condition and the
filter number were recorded.
(xi) The initial elapsed time was recorded.
(xii) At the end of sampling, on site temperature and
atmospheric pressure readings were taken and the final flow rate of the HVS was
checked and recorded.
(xiii) The final elapsed time was recorded.
(xiv) The sampled filter was removed carefully and folded
in half length so that only surfaces with collected particulate matter were in
contact.
(xv) It was then placed in a clean plastic envelope and
sealed.
(xvi) All monitoring information was recorded on a
standard data sheet.
(xvii) Filters were then sent to ALS Technichem (HK) Pty
Ltd. for analysis.
(d) Maintenance and Calibration
(i) The HVS and its accessories were maintained in good
working condition, such as replacing motor brushes routinely and checking
electrical wiring to ensure a continuous power supply.
(ii) 5-point calibration of the HVS was conducted using
TE-5025A Calibration Kit
prior to the commencement of baseline monitoring. Bi-monthly 5-point
calibration of the HVS will be carried out during impact monitoring.
(iii) Calibration certificate of the HVSs are provided in
Appendix C.
2.5.2
1-hour TSP Monitoring
(a) Measuring Procedures
The measuring procedures of
the 1-hour dust meter were in accordance with the 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.
2.6.1
The schedule for air quality monitoring in June
2017 is provided in Appendix D.
2.7.1
The monitoring results for 1-hour TSP and
24-hour TSP are summarized in Tables 2.6
and 2.7 respectively. Detailed
impact air quality monitoring results and relevant graphical plots are
presented in Appendix E.
Table 2.6 Summary of 1-hour TSP
Monitoring Results During the Reporting Month
Monitoring Station
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level (mg/m3)
|
Limit Level (mg/m3)
|
AMS5
|
16
|
8 ¡V 36
|
352
|
500
|
AMS6
|
13
|
4 ¡V 28
|
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
|
34
|
30 ¡V 39
|
164
|
260
|
AMS6
|
48
|
23 ¡V 95
|
173
|
260
|
2.7.2
No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6
during the reporting month.
2.7.3
The event action plan is annexed in Appendix F.
2.7.4 The wind data obtained from the on-site weather
station during the reporting month is shown in Appendix G.
3.1.1 In
accordance with the Contract Specific EM&A Manual, impact noise monitoring
was conducted for at least once per week during the construction phase of the
Project. The Action and Limit level of the noise monitoring is provided in Table 3.1.
Table 3.1 Action
and Limit Levels for Noise during Construction Period
Monitoring Station
|
Time Period
|
Action Level
|
Limit Level
|
NMS5 ¡V Ma Wan
Chung Village (Ma Wan Chung Resident Association) (Tung Chung)
|
0700-1900
hours on normal weekdays
|
When one
documented complaint is received
|
75 dB(A)
|
3.2.1 Noise
monitoring was performed using sound level meters at each designated monitoring
station. The sound level meters
deployed comply with the International Electrotechnical Commission Publications
(IEC) 651:1979 (Type 1) and 804:1985 (Type 1) specifications. Acoustic calibrator was deployed to
check the sound level meters at a known sound pressure level. Brand and model of the equipment are
given in Table 3.2.
Table 3.2 Noise
Monitoring Equipment
Equipment
|
Brand and Model
|
Integrated
Sound Level Meter
|
B&K 2238
|
Acoustic
Calibrator
|
B&K 4231
|
3.3.1 Monitoring
location NMS5 was set
up at the proposed locations in accordance with Contract Specific EM&A
Manual.
3.3.2 Figure 2.1 shows
the locations of monitoring stations. Table
3.3
describes the details of the monitoring stations.
Table 3.3 Locations
of Impact Noise Monitoring Stations
Monitoring Station
|
Location
|
NMS5
|
Ma Wan Chung
Village (Ma Wan Chung Resident Association) (Tung Chung)
|
3.4.1
Table 3.4
summarizes the monitoring parameters, frequency and duration of impact noise
monitoring.
Table 3.4 Noise
Monitoring Parameters, Frequency and Duration
Parameter
|
Frequency and Duration
|
30-mins
measurement at each monitoring station between 0700 and 1900 on normal
weekdays (Monday to Saturday). Leq, L10 and L90
would be recorded.
|
At least once
per week
|
3.5.1
Monitoring Procedure
(a) The sound level
meter was set on a tripod at a height of 1.2 m above the podium for free-field measurements at NMS5. A correction of +3 dB(A) shall be made to the
free field measurements.
(b) The battery
condition was checked to ensure the correct functioning of the meter.
(c)
Parameters such
as frequency weighting, the time weighting and the measurement time were set as
follows:-
(i) frequency
weighting: A
(ii) time
weighting: Fast
(iii) time
measurement: Leq(30-minutes) during non-restricted hours i.e. 07:00
¡V 1900 on normal weekdays
(d) Prior to and
after each noise measurement, the meter was calibrated using the acoustic
calibrator for 94.0 dB(A) at 1000 Hz.
If the difference in the calibration level before and after measurement
was more than 1.0 dB(A), the measurement would be considered invalid and repeat
of noise measurement would be required after re-calibration or repair of the
equipment.
(e) During the
monitoring period, the Leq, L10 and L90 were
recorded. In addition, site
conditions and noise sources were recorded on a standard record sheet.
(f) Noise
measurement was paused during periods of high intrusive noise (e.g. dog
barking, helicopter noise) if possible. Observations were recorded when
intrusive noise was unavoidable.
(g) Noise monitoring
was cancelled in the presence of fog, rain, wind with a steady speed exceeding 5m/s, or wind with gusts exceeding 10m/s. The wind speed shall be checked with a
portable wind speed meter capable of measuring the wind speed in m/s.
3.5.2
Maintenance and Calibration
(a) The
microphone head of the sound level meter was cleaned with soft cloth at regular
intervals.
(b) The
meter and calibrator were sent to the supplier or HOKLAS laboratory to check
and calibrate at yearly intervals.
(c) Calibration
certificates of the sound level meters and acoustic calibrators are provided in
Appendix C.
3.6.1
The schedule for construction noise monitoring
in June 2017 is provided in Appendix D.
3.7.1 The
monitoring results for construction noise are summarized in Table 3.5 and the monitoring results
and relevant graphical plots are provided in Appendix E.
Table
3.5 Summary
of Construction Noise Monitoring Results During the Reporting Month
Monitoring
Station
|
Average Leq
(30 mins), dB(A)
|
Range of Leq (30 mins), dB(A)
|
Limit Level Leq (30 mins), dB(A)
|
NMS5
|
66
|
60 ¡V 70
|
75
|
3.7.2
There
were no Action and Limit Level exceedances for noise during daytime on normal
weekdays of the reporting month.
3.7.3 Major
noise sources during the noise monitoring included construction activities of
the Contract and nearby traffic.
3.7.4
The event action plan is annexed in Appendix F.
4
Water
Quality Monitoring
4.1.1
Impact water quality monitoring was carried out
to ensure that any deterioration of water quality is detected, and that timely
action is taken to rectify the situation.
For impact water quality monitoring, measurements were taken in
accordance with the Contract Specific EM&A Manual. Table 4.1 shows the established Action/Limit Levels for the
environmental monitoring works. The ET proposed to amend the Acton Level
and Limit Level for turbidity and suspended solid and EPD approved ET¡¦s
proposal on 25 March 2013.
Therefore, Action Level and Limit Level for the Contract have been
changed since 25 March 2013.
4.1.2
The original and revised
Action Level and Limit Level for turbidity and suspended solid are shown in Table 4.1.
Table 4.1 Action
and Limit Levels for Water Quality
Parameter (unit)
|
Water Depth
|
Action Level
|
Limit Level
|
Dissolved
Oxygen (mg/L) (surface, middle and bottom)
|
Surface and
Middle
|
5.0
|
4.2 except 5
for Fish Culture Zone
|
Bottom
|
4.7
|
3.6
|
Turbidity
(NTU)
|
Depth average
|
27.5 or 120%
of upstream control 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.
4.2.1 The
monitoring equipment used in the impact water quality monitoring programme are
detailed in the Monthly EM&A Report for June 2017 prepared for Contract No.
HY/2010/02 and Contract No. HY/2011/09.
4.3.1
Table 4.3
summarizes the monitoring parameters, frequency and monitoring depths of impact
water quality monitoring as required in the Contract Specific EM&A Manual.
Table 4.3 Impact
Water Quality Monitoring Parameters and Frequency
Monitoring Stations
|
Parameter, unit
|
Frequency
|
No. of depth
|
Impact Stations:
IS5, IS(Mf)6, IS7, IS8, IS(Mf)9
& IS10,
Control/Far Field Stations:
CS2 & CS(Mf)5,
Sensitive Receiver
Stations:
SR3, SR4, SR5, SR10A &
SR10B
|
¡P
Depth, m
¡P
Temperature, oC
¡P
Salinity, ppt
¡P
Dissolved Oxygen (DO), mg/L
¡P
DO Saturation, %
¡P
Turbidity, NTU
¡P
pH
¡P
Suspended Solids (SS), mg/L
|
Three times per week
during mid-ebb and mid-flood tides (within ¡Ó 1.75 hour of the predicted time)
|
3
(1 m below water surface,
mid-depth and 1 m above sea bed, except where the water depth is less than 6
m, in which case the mid-depth station may be omitted. Should the water depth
be less than 3 m, only the mid-depth station will be monitored).
|
4.4.1 In
accordance with the Contract Specific EM&A Manual, thirteen stations (6 Impact
Stations, 5
Sensitive Receiver Stations and 2 Control
Stations) were designated for impact water quality monitoring. The six Impact
Stations (IS) were chosen on the basis of their proximity to the reclamation
and thus the greatest potential for water quality impacts, the five
Sensitive Receiver Stations (SR) were chosen as they are close to the key
sensitive receives and the two Control Stations (CS) were chosen to facilitate
comparison of the water quality of the IS stations with less influence by the
Project/ ambient water quality conditions.
4.4.2 Technical
issues have been observed from impact monitoirng of the Contract and thus
published information from Monthly EM&A Report for June 2017 prepared
for Contract No. HY/2010/02 and Contract No. HY/2011/09 were adopted for the
Contract.
4.4.3
Due to
safety concern and topographical condition of the original locations of SR4 and
SR10B, alternative impact water quality monitoring stations, naming as SR4(N)
and SR10B(N), were adopted, which are situated in vicinity of the original
impact water quality monitoring stations (SR4 and SR10B) and could be reachable.
4.4.4
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 SR5 and IS10 are enclosed by works boundary of 3RS Project.
Alternative impact water quality monitoring stations, naming as SR5(N) and
IS10(N) was approved in 12 May 2017 and were adopted starting from 15 May 2017
to replace the original locations of water quality monitoring for Contract No.
HY/2010/02.
4.4.5
The locations of these monitoring stations 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
|
Impact Station
(Close to HKBCF construction site)
|
812577
|
820670
|
IS10(N)
|
Impact Station
(Close to HKBCF construction site)
|
812942
|
820881
|
SR3
|
Sensitive
receivers (San Tau SSSI)
|
810525
|
816456
|
SR4
|
Sensitive
receivers (Tai Ho Inlet)
|
814760
|
817867
|
SR4(N)
|
Sensitive
receivers (Tai Ho Inlet)
|
814705
|
817859
|
SR5
|
Sensitive
receivers (Artificial Reef In NE Airport)
|
811489
|
820455
|
SR5(N)
|
Sensitive
receivers (Artificial Reef In NE Airport)
|
812569
|
821475
|
SR10A
|
Sensitive
receivers (Ma Wan Fish Culture Zone)
|
823741
|
823495
|
SR10B
|
Sensitive
receivers (Ma Wan Fish Culture Zone)
|
823686
|
823213
|
SR10B(N)
|
Sensitive
receivers (Ma Wan Fish Culture Zone)
|
823683
|
823187
|
CS2
|
Control
Station (Mid-Ebb)
|
805849
|
818780
|
CS(Mf)5
|
Control
Station (Mid-Flood)
|
817990
|
821129
|
Remarks:
1) Technical issues have been
observed from impact monitoirng of the Contract and thus published informatin
from Monthly EM&A Report
for June 2017 prepared for Contract No.
HY/2010/02 and Contract No. HY/2011/09 were adopted for the Contract.
2)
Due to safety concern and topographical condition of the original
locations of SR4 and SR10B, alternative impact water quality monitoring
stations, naming as SR4(N) and SR10B(N), were adopted, which are situated in
vicinity of the original impact water quality monitoring stations (SR4 and
SR10B) and could be reachable.
3)
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 SR5 and IS10 are enclosed by works boundary of 3RS
Project. Alternative impact water quality monitoring stations, naming as
SR5(N) and IS10(N) was approved in 12 May 2017 and were adopted starting from
15 May 2017 to replace the original locations of water quality monitoring for
Contract No. HY/2010/02.
|
4.5
Monitoring Methodology
4.5.1 The
monitoring methodology is detailed in the Monthly EM&A Report for June 2017
prepared for Contract No. HY/2010/02 and Contract No. HY/2011/09.
4.6
Monitoring Schedule for the Reporting
Month
4.6.1 The
monitoring schedule for impact water quality monitoring in June 2017 is
detailed in the Monthly EM&A Report prepared for Contract No. HY/2010/02
and Contract No. HY/2011/09.
4.7.1
The monitoirng results of water quality monitoring for all stations
except station CS2 were adopted from the published Monthly EM&A Report for
Contract No. HY/2010/02.
4.7.2
The monitoirng results of water quality monitoring for station CS2
was adopted from the published Monthly EM&A Report Contract No. HY/2011/09.
4.7.3
For
marine water quality monitoring, no Action Level and Limit Level exceedances
of dissolved
oxygen, turbidity and suspended solid levels were recorded by the ET of
Contract No. HY/2010/02 and Contract No. HY/2011/09 during the reporting month.
4.7.4
The
event action plan is annexed in Appendix F.
5.1.1
Impact dolphin monitoring is required to be conducted by a qualified dolphin
specialist team to evaluate whether there have been any effects on the dolphins.
5.1.2
The Action Level and Limit Level for dolphin
monitoring are shown in Table 5.1.
Table 5.1 Action
and Limit Levels for Dolphin Monitoring
|
North Lantau Social Cluster
|
NEL
|
NWL
|
Action Level
|
STG < 4.2 & ANI < 15.5
|
STG < 6.9
& ANI < 31.3
|
Limit Level
|
(STG < 2.4
& ANI < 8.9) and (STG < 3.9 & ANI < 17.9)
|
Remarks:
1. STG means quarterly encounter rate of number of dolphin sightings.
2. ANI means quarterly encounter rate of total number of dolphins.
3. For North Lantau Social Cluster, AL will be trigger if either NEL or NWL fall below the criteria; LL will
be triggered if both NEL and NWL
fall below the criteria.
5.1.3
The
revised Event and Action Plan for dolphin Monitoring was approved by EPD in 6
May 2013. The revised Event and Action Plan is
annexed in Appendix
F.
Vessel-based
Line-transect Survey
5.2.1 According to the requirements of the Updated
EM&A Manual for HKLR (Version 1.0), dolphin monitoring programme should
cover all transect lines in NEL and NWL survey areas (see Figure 1 of Appendix H) twice per month. The co-ordinates of all
transect lines are shown in Table 5.2.
The coordinates of several starting
points 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, and the revised coordinates are in red and marked with
an asterisk in Table 5.2.
Table 5.2 Co-ordinates
of Transect Lines
Line No.
|
Easting
|
Northing
|
|
Line No.
|
Easting
|
Northing
|
1
|
Start Point
|
804671
|
815456*
|
|
13
|
Start Point
|
816506
|
819480
|
1
|
End Point
|
804671
|
831404
|
|
13
|
End Point
|
816506
|
824859
|
2
|
Start Point
|
805475
|
815913*
|
|
14
|
Start Point
|
817537
|
820220
|
2
|
End Point
|
805477
|
826654
|
|
14
|
End Point
|
817537
|
824613
|
3
|
Start Point
|
806464
|
819435
|
|
15
|
Start Point
|
818568
|
820735
|
3
|
End Point
|
806464
|
822911
|
|
15
|
End Point
|
818568
|
824433
|
4
|
Start Point
|
807518
|
819771
|
|
16
|
Start Point
|
819532
|
821420
|
4
|
End Point
|
807518
|
829230
|
|
16
|
End Point
|
819532
|
824209
|
5
|
Start Point
|
808504
|
820220
|
|
17
|
Start Point
|
820451
|
822125
|
5
|
End Point
|
808504
|
828602
|
|
17
|
End Point
|
820451
|
823671
|
6
|
Start Point
|
809490
|
820466
|
|
18
|
Start Point
|
821504
|
822371
|
6
|
End Point
|
809490
|
825352
|
|
18
|
End Point
|
821504
|
823761
|
7
|
Start Point
|
810499
|
820880*
|
|
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
|
820872
|
|
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
|
|
|
|
|
|
12
|
End Point
|
815542
|
824882
|
|
|
|
|
|
Note:
Co-ordinates in red and marked with asterisk are revised co-ordinates of
transect line.
5.2.2
The survey team used standard line-transect methods
(Buckland et al. 2001) to conduct the systematic vessel surveys, and followed
the same technique of data collection that has been adopted over the last 18
years of marine mammal monitoring surveys in Hong Kong developed by HKCRP (see
Hung 2015). For each monitoring
vessel survey, a 15-m inboard vessel with an open upper deck (about 4.5 m above
water surface) was used to make observations from the flying bridge area.
5.2.3
Two experienced observers (a data recorder and a
primary observer) made up the on-effort survey team, and the survey vessel
transited different transect lines at a constant speed of 13-15 km per
hour. The data recorder searched
with unaided eyes and filled out the datasheets, while the primary observer
searched for dolphins and porpoises continuously through 7 x 50 Fujinon marine binoculars. Both observers searched the sea ahead of
the vessel, between 270o and 90o (in relation to the bow,
which is defined as 0o).
One to two additional experienced observers were available on the boat
to work in shift (i.e. rotate every 30 minutes) in order to minimize fatigue of
the survey team members. All
observers were experienced in small cetacean survey techniques and identifying
local cetacean species.
5.2.4 During on-effort
survey periods, the survey team recorded effort data including time, position
(latitude and longitude), weather conditions (Beaufort sea state and visibility),
and distance traveled in each series (a continuous period of search effort)
with the assistance of a handheld GPS (Garmin
eTrex Legend).
5.2.5
Data including time, position and vessel speed were
also automatically and continuously logged by handheld GPS throughout the
entire survey for subsequent review.
5.2.6
When dolphins were sighted, the survey team would
end the survey effort, and immediately record the initial sighting distance and
angle of the dolphin group from the survey vessel, as well as the sighting time
and position. Then the research
vessel was diverted from its course to approach the animals for species
identification, group size estimation, assessment of group composition, and
behavioural observations. The
perpendicular distance (PSD) of the dolphin group to the transect line was
later calculated from the initial sighting distance and angle.
5.2.7
Survey effort being conducted along the parallel
transect lines that were perpendicular to the coastlines (as indicated in Figure 1 of Appendix H) was labeled as
¡§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.
5.2.8
Encounter rates of Chinese white dolphins (number
of on-effort sightings per 100 km of survey effort and number of dolphins from
all on-effort sightings per 100 km of survey effort) were calculated in NEL and
NWL survey areas in relation to the amount of survey effort conducted during
each month of monitoring survey.
Only data collected under Beaufort 3 or below condition would be used
for encounter rate analysis.
Dolphin encounter rates were calculated using primary survey effort
alone, as well as the combined survey effort from both primary and secondary
lines.
Photo-identification Work
5.2.9
When a group of Chinese White Dolphins were sighted
during the line-transect survey, the survey team would end effort and approach
the group slowly from the side and behind to take photographs of them. Every attempt was made to photograph
every dolphin in the group, and even photograph both sides of the dolphins,
since the colouration and markings on both sides may not be symmetrical.
5.2.10
A professional digital camera (Canon EOS 7D or 60D model), equipped with long telephoto lenses
(100-400 mm zoom), were available on board for researchers to take sharp,
close-up photographs of dolphins as they surfaced. The images were shot at the highest
available resolution and stored on Compact Flash memory cards for downloading
onto a computer.
5.2.11
All digital images taken in the field were first
examined, and those containing potentially identifiable individuals were sorted
out. These photographs would then
be examined in greater detail, and were carefully compared to the existing
Chinese White Dolphin photo-identification catalogue maintained by HKCRP since
1995.
5.2.12 Chinese White
Dolphins can be identified by their natural markings, such as nicks, cuts,
scars and deformities on their dorsal fin and body, and their unique spotting
patterns were also used as secondary identifying features (Jefferson 2000).
5.2.13 All photographs of
each individual were then compiled and arranged in chronological order, with
data including the date and location first identified (initial sighting),
re-sightings, associated dolphins, distinctive features, and age classes
entered into a computer database. Detailed
information on all identified individuals will be further presented as an
appendix in quarterly EM&A reports.
Vessel-based
Line-transect Survey
5.3.1
During the month of June
2017, two sets of systematic line-transect vessel surveys were conducted on the
14th, 15th, 20th and 26th to cover
all transect lines in NWL and NEL survey areas twice. The survey routes of each
survey day are presented in Figures 2 to
5 of Appendix H.
5.3.2 From
these surveys, a total of 258.04 km of survey effort was collected, with 93.8%
of the total survey effort being conducted under favourable weather conditions
(i.e. Beaufort Sea State 3 or below with good visibility) (Annex I of Appendix H). Among the two areas, 90.70 km and 167.34
km of survey effort were collected from NEL and NWL survey areas
respectively. Moreover, the total
survey effort conducted on primary lines was 189.45 km, while the effort on secondary
lines was 68.59 km.
5.3.3
During
the two sets of monitoring surveys in June 2017, only two groups of five
Chinese White Dolphins were sighted (see Annex
II of Appendix H).
Both dolphin sightings were made in NWL, while none was sighted in NEL.
5.3.4
For the
surveys conducted in June 2017, both dolphin groups were sighted during
on-effort search on secondary lines (Annex
II of Appendix H).
The sightings were not associated with any operating fishing
vessel.
5.3.5
Distribution
of the dolphin sightings made in June 2017 is shown in Figure 6 of Appendix H.
One of the dolphin groups was sighted near Black Point at the mouth of
Deep Bay, and another dolphin group was sighted near Castle Peak Power Station
(Figure 6 of Appendix H).
As in previous monitoring months, both sightings were made far away from
the HKLR03/HKBCF reclamation sites as well as the HKLR09/TMCLKL alignments (Figure 6 of Appendix H).
5.3.6
During
the June¡¦s surveys, encounter rates of Chinese White Dolphins deduced from the
survey effort and on-effort sighting data made under favourable conditions
(Beaufort 3 or below) are shown in Tables
5.3 and 5.4.
Table
5.3 Individual Survey Event Encounter Rates
|
Encounter rate (STG)
(no. of
on-effort dolphin sightings per 100 km of survey effort)
|
Encounter rate (ANI)
(no. of dolphins
from all on-effort sightings per 100 km of survey effort)
|
Primary Lines Only
|
Primary Lines Only
|
NEL
|
Set 1: June 14th / 15th
|
0.0
|
0.0
|
Set 2: June 20th / 26th
|
0.0
|
0.0
|
NWL
|
Set 1: June 14th / 15th
|
0.0
|
0.0
|
Set 2: June 20th / 26th
|
0.0
|
0.0
|
Remarks:
1. Dolphin Encounter Rates Deduced
from the Two Sets of Surveys (Two Surveys in Each Set) in June 2017 in
Northeast Lantau (NEL) and Northwest Lantau (NWL).
Table 5.4 Monthly
Average Encounter Rates
|
Encounter rate (STG)
(no. of on-effort dolphin sightings per 100 km of
survey effort)
|
Encounter rate (ANI)
(no. of dolphins
from all on-effort sightings per 100 km of survey effort)
|
Primary
Lines Only
|
Both Primary and Secondary Lines
|
Primary
Lines Only
|
Both Primary and
Secondary Lines
|
Northeast Lantau
|
0.0
|
0.0
|
0.0
|
0.0
|
Northwest Lantau
|
0.0
|
0.7
|
0.0
|
0.7
|
Remarks:
1. Monthly Average Dolphin
Encounter Rates (Sightings Per 100 km of Survey Effort) from All Four Surveys
Conducted in June 2017 on Primary Lines only as well as Both Primary Lines and
Secondary Lines in Northeast Lantau (NEL) and Northwest Lantau (NWL).
5.3.7
The average dolphin group size in June 2017 was
2.5 individuals per group, which was lower than the ones in previous months of
monitoring surveys despite the very small sample size (with only two groups).
Photo-identification Work
5.3.8
Five known individual dolphins were sighted five
times during June¡¦s surveys (Annexes III
and IV of Appendix
H).
All individuals were re-sighted only once during the monthly surveys in
June.
5.3.9
Notably, two of these individuals (i.e. NL33 and
NL322) were mother-calf pair during their re-sightings in June 2017.
Conclusion
5.3.10
During this month of dolphin monitoring, no
adverse impact from the activities of this construction project on Chinese
White Dolphins was noticeable from general observations.
5.3.11
Due to monthly variation in dolphin occurrence
within the study area, it would be more appropriate to draw conclusion on
whether any impacts on dolphins have been detected related to the construction
activities of this project in the quarterly EM&A report, where comparison
on distribution, group size and encounter rates of dolphins between the
quarterly impact monitoring period (June ¡V August 2017) and baseline monitoring
period (3-month period) will be made.
5.4.1
Buckland, S. T., Anderson, D. R., Burnham, K. P.,
Laake, J. L., Borchers, D. L., and Thomas, L. 2001. Introduction to distance sampling:
estimating abundance of biological populations. Oxford University Press, London.
5.4.2
Hung, S. K.
2015. Monitoring of Marine
Mammals in Hong Kong waters: final report (2014-15). An unpublished report submitted to the
Agriculture, Fisheries and Conservation Department, 198 pp.
5.4.3
Jefferson,
T. A. 2000. Population biology of the Indo-Pacific
hump-backed dolphin in Hong Kong waters.
Wildlife Monographs 144:1-65.
Methodology
6.1.1 To avoid
disturbance to the mudflat and nuisance to navigation, no fixed
marker/monitoring rod was installed at the monitoring stations. A high
precision Global Navigation Satellite System (GNSS) real time location fixing
system (or equivalent technology) was used to locate the station in the
precision of 1mm, which is reasonable under flat mudflat topography with uneven
mudflat surface only at micro level.
This method has been used on Agricultural Fisheries and Conservation
Department¡¦s (AFCD) project, namely Baseline Ecological Monitoring Programme
for the Mai Po Inner Deep Bay Ramsar Site for measurement of seabed levels.
6.1.2 Measurements
were taken directly on the mudflat surface. The Real Time Kinematic GNSS (RTK GNSS)
surveying technology was used to measure mudflat surface levels and 3D
coordinates of a survey point. The
RTK GNSS survey was calibrated against a reference station in the field before
and after each survey. The
reference station is a survey control point established by the Lands Department
of the HKSAR Government or traditional land surveying methods using
professional surveying instruments such as total station, level and/or geodetic
GNSS. The coordinates system was in
HK1980 GRID system. For this
contract, the reference control station was surveyed and established by
traditional land surveying methods using professional surveying instruments
such as total station, level and RTK GNSS.
The accuracy was down to mm level so that the reference control station
has relatively higher accuracy. As
the reference control station has higher accuracy, it was set as true
evaluation relative to the RTK GNSS measurement. All position and height correction were
adjusted and corrected to the reference control station. Reference station survey result and
professional land surveying calibration is shown as Table 6.1:
Table 6.1 Reference
Station Survey result and GNSS RTK calibration result of Round 1
Reference Station
|
Easting (m)
|
Northing (m)
|
Baseline reference elevation (mPD) (A)
|
Round 1 Survey (mPD) (B)
|
Calibration Adjustment (B-A)
|
T1
|
811248.660mE
|
816393.173mN
|
3.840
|
3.817
|
-0.023
|
T2
|
810806.297mE
|
815691.822mN
|
4.625
|
4.653
|
+0.028
|
T3
|
810778.098mE
|
815689.918mN
|
4.651
|
4.660
|
+0.009
|
T4
|
810274.783mE
|
816689.068mN
|
2.637
|
2.709
|
+0.072
|
6.1.3 The
precision of the measured mudflat surface level reading (vertical precision
setting) was within 10 mm (standard deviation) after averaging the valid survey
records of the XYZ HK1980 GRID coordinates. Each survey record at each station was
computed by averaging at least three measurements that are within the above
specified precision setting. Both digital data logging and written records were
collected in the field. Field data
on station fixing and mudflat surface measurement were recorded.
Monitoring Locations
6.1.4 Four
monitoring stations were established based on the site conditions for the
sedimentation monitoring and are shown in Figure 6.1.
Monitoring Results
6.1.5 The
baseline sedimentation rate monitoring was in September 2012 and impact
sedimentation rate monitoring was undertaken on 8
June 2017. The
mudflat surface levels at the four established monitoring stations and the
corresponding XYZ HK1980 GRID coordinates are presented in Table 6.2 and Table 6.3.
Table 6.2 Measured
Mudflat Surface Level Results
|
Baseline Monitoring (September 2012)
|
Impact Monitoring (June 2017)
|
Monitoring
Station
|
Easting
(m)
|
Northing
(m)
|
Surface
Level
(mPD)
|
Easting
(m)
|
Northing
(m)
|
Surface
Level
(mPD)
|
S1
|
810291.160
|
816678.727
|
0.950
|
810291.155
|
816678.715
|
1.078
|
S2
|
810958.272
|
815831.531
|
0.864
|
810958.328
|
815831.484
|
0.990
|
S3
|
810716.585
|
815953.308
|
1.341
|
810716.604
|
815953.296
|
1.447
|
S4
|
811221.433
|
816151.381
|
0.931
|
811221.440
|
816151.355
|
1.116
|
Table 6.3 Comparison
of measurement
|
Comparison of measurement
|
Remarks and Recommendation
|
Monitoring
Station
|
Easting
(m)
|
Northing
(m)
|
Surface
Level
(mPD)
|
S1
|
-0.005
|
-0.012
|
0.128
|
Level
continuously increased
|
S2
|
0.056
|
-0.047
|
0.126
|
Level
continuously increased
|
S3
|
0.019
|
-0.012
|
0.106
|
Level
continuously increased
|
S4
|
0.007
|
-0.026
|
0.185
|
Level
continuously increased
|
6.1.6
This measurement result was generally and
relatively higher than the baseline measurement at S1, S2, S3 and S4. The
mudflat level is continuously increased.
6.2.1 The
mudflat monitoring covered water quality monitoring data. Reference was made to the water quality
monitoring data of the representative water quality monitoring station (i.e. SR3)
as in the EM&A Manual. The
water quality monitoring location (SR3) is shown in Figure 2.1.
6.2.2 Impact
water quality monitoring in San Tau (monitoring station SR3) was conducted in
June 2017. The monitoring
parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).
6.2.3
The impact water quality monitoring results for
SR3 in June 2017 were adopted from the published
Monthly EM&A Report for Contract No. HY/2010/02.
6.3
Mudflat
Ecology Monitoring Methodology
Sampling Zone
6.3.1 In order to collect baseline information of
mudflats in the study site, the study site was divided into three sampling
zones (labeled as TC1, TC2, TC3) in Tung Chung Bay and one zone in San Tau (labeled as ST) (Figure 2.1 of Appendix I). The horizontal
shoreline of sampling zones TC1, TC2, TC3 and ST were about 250 m, 300 m, 300 m
and 250 m respectively (Figure 2.2 of Appendix I). Survey of
horseshoe crabs, seagrass beds and intertidal communities were conducted in
every sampling zone. The present survey was conducted in June 2017 (totally 5
sampling days between 2nd and 11th June 2017).
6.3.2 Since the field survey of Jun. 2016,
increasing number of trashes and even big trashes (Figure 2.3 of Appendix I) were found in every sampling zone. It
raised a concern about the solid waste dumping and current-driven waste issues
in Tung Chung Wan. Respective measures (e.g. manual clean-up) should be
implemented by responsible units.
Horseshoe Crabs
6.3.3
Active search method was conducted for horseshoe
crab monitoring by two experienced surveyors in every sampling zone. During the
search period, any accessible and potential area would be investigated for any
horseshoe crab individuals within 2-3 hours of low tide period (tidal level
below 1.2 m above Chart Datum (C.D.)). Once a horseshoe crab individual was
found, the species was identified referencing to Li (2008). The prosomal width,
inhabiting substratum and respective GPS coordinate were recorded. A
photographic record was taken for future investigation. Any grouping behavior
of individuals, if found, was recorded. The horseshoe crab surveys were
conducted on 2nd (for TC1), 3rd (for TC2) and 9th
(for TC3 and ST) June 2017. The weather was generally hot on all field days
without rainfall.
6.3.4
In present survey (Jun. 2017), a big horseshoe crab
was tangled by a trash gill net in ST mudflat (Figure 2.3 of Appendix I). It was
released to sea once after photo recording. The horseshoe crab of such size
should be inhabitating sub-tidal environment while it forages on intertidal
shore occasionally during high tide period. If it is tangled by the trash net
for few days, it may die due to starvation or overheat during low tide period.
These trash gill nets are definitely ¡¥fatal trap¡¦ for the horseshoe crabs and
other marine life. Manual clean-up should be implemented as soon as possible by
responsible units.
Seagrass Beds
6.3.5 Active search
method was conducted for seagrass bed monitoring by two experienced surveyors
in every sampling zone. During the search period, any accessible and potential
area would be investigated for any seagrass beds within 2-3 hours of low tide
period. Once seagrass bed was found, the species, estimated area, estimated
coverage percentage and respective GPS coordinates were recorded. The seagrass
beds surveys were conducted on 2nd (for TC1), 3rd (for
TC2) and 9th (for TC3 and ST) June 2017. The weather was generally
hot on all field days without rainfall.
Intertidal Soft Shore Communities
6.3.6
The intertidal soft shore community surveys were
conducted in low tide period on 2nd (for TC1), 3rd (for
TC2), 10th (for TC3) and 11th (for ST) June 2017. In
every sampling zone, three 100m horizontal transect lines were laid at high
tidal level (H: 2.0 m above C.D.), mid tidal level (M: 1.5 m above C.D.) and
low tidal level (L: 1.0 m above C.D.). Along every horizontal transect line,
ten random quadrats (0.5 m x 0.5 m) were placed.
6.3.7
Inside a quadrat, any visible epifauna were
collected and were in-situ identified
to the lowest practical taxonomical resolution. Whenever possible a hand core
sample (10 cm internal diameter 20 cm depth) of sediments was collected in the
quadrat. The core sample was gently washed through a sieve of mesh size 2.0 mm in-situ. Any visible infauna were
collected and identified. Finally the top 5 cm surface sediments was dug for
visible infauna in the quadrat regardless of hand core sample was taken.
6.3.8
All
collected fauna were released after recording except some tiny individuals that
are too small to be identified on site. These tiny individuals were taken to
laboratory for identification under dissecting microscope.
6.3.9
The taxonomic classification was conducted in
accordance to the following references: Polychaetes: Fauchald (1977), Yang and
Sun (1988); Arthropods: Dai and Yang (1991), Dong (1991); Mollusks: Chan and
Caley (2003), Qi (2004).
Data Analysis
6.3.10
Data collected from direct search and core
sampling was pooled in every quadrat for data analysis. Shannon-Weaver
Diversity Index (H¡¦) and Pielou¡¦s
Species Evenness (J) were calculated
for every quadrat using the formulae below,
H¡¦= -£U ( 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.
6.4.1
In the event of the impact monitoring results indicating
that the density or the distribution pattern of intertidal fauna and seagrass
is found to be significant different to the baseline condition (taking into
account natural fluctuation in the occurrence and distribution pattern such as
due to seasonal change), appropriate actions should be taken and additional
mitigation measures should be implemented as necessary. Data should then be re-assessed and the
need for any further monitoring should be established. The action plan, as given in Table 6.5 should be undertaken within a
period of 1 month after a significant difference has been determined.
Table
6.5 Event and
Action Plan for Mudflat Monitoring
Event
|
ET Leader
|
IEC
|
SO
|
Contractor
|
Density or the distribution
pattern of horseshoe crab, seagrass or intertidal soft shore communities
recorded in the impact or post-construction monitoring are significantly lower than or different
from those recorded in the baseline monitoring.
|
Review historical data
to ensure differences are as a result of natural variation or previously
observed seasonal differences;
Identify source(s) of
impact;
Inform the IEC, SO and
Contractor;
Check monitoring data;
Discuss additional
monitoring and any other measures, with the IEC and Contractor.
|
Discuss monitoring with
the ET and the Contractor;
Review proposals for
additional monitoring and any other measures submitted by the Contractor and
advise the SO accordingly.
|
Discuss with the IEC
additional monitoring requirements and any other measures proposed by the ET;
Make agreement on the
measures to be implemented.
|
Inform the SO and in
writing;
Discuss with the ET and
the IEC and propose measures to the IEC and the ER;
Implement the agreed
measures.
|
Notes:
ET ¡V
Environmental Team
IEC ¡V Independent
Environmental Checker
SO ¡V Supervising
Officer
Horseshoe Crabs
6.5.1 In the present survey, two species of horseshoe
crab Carcinoscorpius rotundicauda
(total 133 ind.) and Tachypleus
tridentatus (total 125 ind.) were recorded. For one sight record, grouping
of 2-20 individuals was observed at same locations with similar substratum
(fine sand or soft mud, slightly submerged). Photo records were shown in Figure 3.1 of Appendix I while the complete survey records were listed in Annex II of Appendix I. Besides, one tiny individual (prosomal width ~8
mm) was found in TC3 but identification to species was not possible. Hence this
record was excluded from the data analysis.
6.5.2 Table
3.1 of Appendix I summarizes the survey results of horseshoe
crab in the present survey. For Carcinoscorpius
rotundicauda, moderate number of individuals (22 ind.) were found in TC1
that search record was at low-moderate level (5.5 ind. hr-1 person-1).
The average body size was 46.69 mm (prosomal width ranged 15.72-72.49 mm) in
TC1. More individuals were found in TC3 (57 ind.) and ST (54 ind.) resulting in
relatively higher search records (9.0-9.5 ind. hr-1 person-1).
Smaller individuals were found in TC3 that the average body size was 38.95 mm
(prosomal width ranged 14.29-86.73 mm). The average body size was 53.94 mm
(prosomal width ranged 38.83-83.33 mm) in ST. No individual was found in TC2
regardless of a mating pair (to be discussed below).
6.5.3 For Tachypleus tridentatus, there were only
1-2 individuals in TC1 and TC2 (prosomal width ranged 36.33-67.42 mm). The
search record was very low (0.3-0.5 ind. hr-1 person-1).
Similarly, more individuals were found in TC3 (70 ind.) and ST (52 ind.)
respectively. In TC3, the search record was relatlively higher (11.7 ind. hr-1
person-1) while the average body size was 54.24 mm (prosomal width
ranged 27.57-93.44 mm). In ST, the search record was 8.7 ind. hr-1
person-1 while the average body size was 53.74 mm (prosomal width
ranged 40.41-76.37 mm).
6.5.4
In the previous survey of Mar. 2015, there was one
important finding that a mating pair of Carcinoscorpius
rotundicauda was found in ST (prosomal width: male 155.1 mm, female 138.2
mm) (Figure 3.2 of Appendix I). It indicated
the importance of ST as a breeding ground of horseshoe crab. In the present
survey (Jun. 2017), mating pairs of Carcinoscorpius
rotundicauda were also found in TC2 (prosomal width: male 175.27 mm, female
143.51 mm) and TC3 (prosomal width: male 182.08 mm, female 145.63 mm) (Figure 3.2 of Appendix I). It indicated
that breeding of horseshoe crab could occur along the coast of Tung Chung Wan
rather than ST only, as long as suitable substratum was available. The mating
pairs were found nearly burrowing in soft mud at low tidal level (0.5-1.0 m
above C.D.). The smaller male was holding the opisthosoma (abdomen carapace) of
larger female from behind.
6.5.5
In the
present survey (Jun. 2017), one large individual of Carcinoscorpius rotundicauda (prosomal width 178.67 mm) was tangled
by a trash gill net in ST (Figure 3.3 of
Appendix I). Based on the sizes of these mating pairs
and tangled individuals, it indicated that individuals of prosomal width larger
than 100 mm would progress its nursery stage from intertidal habitat to
sub-tidal habitat of Tung Chung Wan. These large individuals might move onto
intertidal shore occasionally during high tide for foraging and breeding.
6.5.6
Because the large individuals (prosomal width >
100 mm) should be inhabiting sub-tidal habitat in most of the time. The records
of mating pair and large, tangled individuals were excluded from the data
analysis to avoid mixing up with juvenile population living on intertidal
habitat. In the previous survey of Jun. 2016, the records of two large
individuals of Carcinoscorpius
rotundicauda (prosomal width 117.37 mm and 178.17 mm) in TC1 were excluded
from data analysis according to the same principle.
6.5.7
No marked
individual of horseshoe crab was recorded in the present survey. Some marked
individuals were found in the previous surveys of Sep. 2013, Mar. 2014 and Sep.
2014. All of them were released through a conservation programme conducted by
Prof. Paul Shin (Department of Biology and Chemistry, The City University of
Hong Kong (CityU)). It was a re-introduction trial of artificial bred horseshoe
crab juvenile at selected sites. So, that the horseshoe crabs population might
be restored in the natural habitat. Through a personal conversation with Prof.
Shin, about 100 individuals were released in the sampling zone ST on 20 June
2013. All of them were marked with color tape and internal chip detected by
specific chip sensor. There should be second round of release between June and
September 2014 since new marked individuals were found in the survey of Sep.
2014.
6.5.8
The
artificial bred individuals, if found, would be excluded from the results of
present monitoring programme in order to reflect the changes of natural
population. However, the mark on their prosoma might have been detached during
moulting after a certain period of release. The artificially released
individuals were no longer distinguishable from the natural population without
the specific chip sensor. The survey data collected would possibly cover both
natural population and artificially bred individuals.
Population difference among the sampling zones
6.5.9
Figures 3.4 and
3.5 of Appendix I show the changes
of number of individuals, mean prosomal width and search record of horseshoe
crabs Carcinoscorpius rotundicauda
and Tachypleus tridentatus
respectively in every sampling zone throughout the monitoring period.
6.5.10
For TC3
and ST, medium to high search records (i.e. number of individuals) of both
species were always found in wet season (Jun. and Sep.). The search record of
ST was higher from Sep. 2012 to Jun. 2014 while it was replaced by TC3 from
Sep. 2014 to Jun. 2015. The search records were similar between two sampling
zones from Sep. 2015 to Jun. 2016. In Sep. 2016, the search record of Carcinoscorpius rotundicauda in ST was
much higher than TC3. From Mar. to Jun. 2017 (present survey), the search
records of both species were similar again between two sampling zones and
increased with warmer climate. It showed a natural variation of horseshoe crab
population in these two zones due to weather condition and tidal effect during
the survey. No obvious difference of horseshoe crab population was noted between
TC3 and ST.
6.5.11
For
TC1, the search record was at low to medium level throughout the monitoring
period. The change of Carcinoscorpius
rotundicauda was relatively more variable than that of Tachypleus tridentatus. Relatively, the search record was very low
in TC2 (2 ind. in Sep. 2013; 1 ind. in Mar., Jun., Sep. 2014, Mar. and Jun.
2015; 4 ind. in Sep. 2015; 6 ind. in Jun. 2016; 1 ind. in Sep. 2016, Mar. and
Jun. 2017).
6.5.12
About the body size, larger individuals of Carcinoscorpius rotundicauda were
usually found in ST and TC1 relative to those in TC3. For Tachypleus tridentatus, larger individuals were usually found in ST
followed by TC3 and TC1.
6.5.13
Throughout
the monitoring period, it was obvious that TC3 and ST (western shore of Tung
Chung Wan) was an important nursery ground for horseshoe crab especially newly
hatched individuals due to larger area of suitable substratum (fine sand or
soft mud) and less human disturbance (far from urban district). Relatively,
other sampling zones were not a suitable nursery ground especially TC2.
Possible factors were less area of suitable substratum (especially TC1) and
higher human disturbance (TC1 and TC2: close to urban district and easily
accessible). In TC2, large daily salinity fluctuation was a possible factor either
since it was flushed by two rivers under tidal inundation. The individuals
inhabiting TC1 and TC2 were confined in small foraging area due to limited area
of suitable substrata. Although a mating pair of Carcinoscorpius rotundicauda was found in TC2, the hatching rate
and survival rate of newly hatched individuals were believed very low.
Seasonal variation of horseshoe crab population
6.5.14 Throughout the
monitoring period, the search record of horseshoe crab declined obviously
during dry season especially December (Figures
3.3 and 3.4 of Appendix I). In Dec. 2012,
4 individuals of Carcinoscorpius
rotundicauda and 12 individuals of Tachypleus
tridentatus were found only. In Dec. 2013, no individual of horseshoe crab
was found. In Dec. 2014, 2 individuals of Carcinoscorpius
rotundicauda and 8 individuals of Tachypleus
tridentatus were found only. In Dec. 2015, 2 individuals of Carcinoscorpius rotundicauda, 6
individuals of Tachypleus tridentatus
and one newly hatched, unidentified individual were found only. The horseshoe
crabs were inactive and burrowed in the sediments during cold weather (<15
ºC). Similar results of low search record in dry season were reported in a
previous territory-wide survey of horseshoe crab. For example, the search
records in Tung Chung Wan were 0.17 ind. hr-1 person-1
and 0.00 ind. hr-1 person-1 in wet season and dry season
respectively (details see Li, 2008). Relatively the search records were much
higher in Dec. 2016. There were totally 70 individuals of Carcinoscorpius rotundicauda and 24 individuals of Tachypleus tridentatus in TC3 and ST.
Because the survey was arranged in early December while the weather was warm
with sunlight (~22 ºC during dawn according to Hong Kong Observatory database,
Chek Lap Kok station on 5 Dec). In contrast, there was no search record in TC1
and TC2 because the survey was conducted in mid-December with colder and cloudy
weather (~20 ºC during dawn on 19 Dec). The horseshoe crab activity would
decrease gradually with the colder climate.
6.5.15 From Sep. 2012 to
Dec. 2013, Carcinoscorpius rotundicauda
was a less common species relative to Tachypleus
tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This
species had ever been believed of very low density in ST hence the encounter
rate was very low. Since Mar. 2014, it was found in all sampling zones with
higher abundance in ST. Based on its average size (mean prosomal width
39.28-49.81 mm), it indicated that breeding and spawning of this species had
occurred about 3 years ago, along the coastline of Tung Chun Wan. However,
these individuals were still small while their walking trails were
inconspicuous. Hence there was no search record in previous sampling months.
Since Mar. 2014, more individuals were recorded due to larger size and higher
activity (i.e. more conspicuous walking trail).
6.5.16
For Tachypleus
tridentatus, sharp increase of number of individuals was recorded in ST
during the wet season of 2013 (from Mar. to Sep.). According to a personal
conversation with Prof. Shin (CityU), his monitoring team had recorded similar
increase of horseshoe crab population during wet season. It was believed that
the suitable ambient temperature increased its conspicuousness. However similar
pattern was not recorded in the following wet seasons. The number of
individuals increased in Mar. and Jun. 2014 followed by a rapid decline in Sep.
2014. Then the number of individuals fluctuated slightly in TC3 and ST until
Mar. 2017. Apart from natural mortality, migration from nursery soft shore to
subtidal habitat was another possible cause. Since the mean prosomal width of Tachypleus
tridentatus continued to grow and reached about 50 mm since Mar. 2014. Then
it varied slightly between 35-65 mm from Sep. 2014 to Mar. 2017. Most of the
individuals might have reached a suitable size (e.g. prosomal width 50-60 mm)
strong enough to forage in sub-tidal habitat. In the present survey (Jun.
2017), the number of individuals increased sharply again in TC3 and ST.
Although mating pair of Tachypleus tridentatus was not found in previous
surveys, there should be new round of spawning in the wet season of 2016. The
individuals might have grown to a more conspicuous size in 2017 accounting for
higher search record.
6.5.17 Recently, Carcinoscorpius rotundicauda was a more
common horseshoe crab species in Tung Chung Wan. It was recorded in the four
sampling zones while the majority located in TC3 and ST. Due to potential
breeding last year, Tachypleus
tridentatus became common again and distributed in TC3 and ST only. Since
TC3 and ST were regarded as important nursery ground for both horseshoe crab
species, box plots of prosomal width of two horseshoe crab species were
constructed to investigate the changes of population in details.
Box plot of
horseshoe crab populations in TC3
6.5.18
Figure 3.6 of Appendix I shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. In Mar 2014, the major size (50% of individual records
between upper (top of box) and lower quartile (bottom of box)) ranged 40-60 mm
while only few individuals were found. From Mar. 2014 to Mar. 2017, the median
prosomal width (middle line of box) and major size (box) decreased after Mar.
of every year. It was due to more small individuals found. It indicated new rounds
of spawning. Also, there were slight increasing trends of body size from Jun.
to Mar. of next year since 2015. It indicated a stable growth of individuals.
Focused on larger juveniles (circle dots above the box), 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.
6.5.19
For Tachypleus
tridentatus, the major size ranged 20-50 mm while the number of individuals
fluctuated from Sep. 2012 to Jun. 2014. Then a slight but consistent growing
trend was observed from Sep. 2014 to Jun. 2015. The prosomal width increased
from 25-35 mm to 35-65 mm. As mentioned, the large individuals might have
reached a suitable size for migrating from the nursery soft shore to subtidal
habitat. It accounted for the declined population in TC3. From Mar. to Sep.
2016, slight increasing trend of major size was noticed again. From Dec. 2016
to Jun. 2017 (present survey), similar increasing trend of major size was noted
with much higher number of individuals. It reflected new round of spawning.
Across the whole monitoring period, the larger juveniles (circle dots above the
box) reached 60-80 mm in prosomal width while it could reach 90 mm in present
survey. Juveniles reaching this size might gradually migrate to sub-tidal
habitats.
Box plot of horseshoe crab populations in ST
6.5.20
Figure 3.7 of Appendix I shows the changes of prosomal width of Carcinoscorpius
rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius
rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the
data were lacking. From Mar. 2014 to Sep. 2016, the size of major population
decreased and more small individuals (i.e. circle dots below the box) were
recorded after Jun. of every year. It indicated new round of spawning. Also,
there were similar increasing trends of body size from Sep. to Jun. of next
year between 2014 and 2017. It indicated a stable growth of individuals. Across
the whole monitoring period, the larger juveniles (i.e. circle dots above the
box) usually ranged 70-80 mm in prosomal width except one individual (prosomal
width 107.04 mm) found in Mar. 2017. It reflected juveniles reaching this size
would gradually migrate to sub-tidal habitats.
6.5.21
For Tachypleus tridentatus, a consistent
growing trend was observed for the major population from Dec. 2012 to Dec. 2014
regardless of change of search record. The prosomal width increased from 15-30
mm to 55-70 mm. As mentioned, the large juveniles might have reached a suitable
size for migrating from the nursery soft shore to subtidal habitat. From Mar.
to Sep. 2015, the size of major population decreased slightly to a prosomal
width 40-60 mm. At the same time, the number of individuals decreased
gradually. It further indicated some of large juveniles might have migrated to
sub-tidal habitat, leaving the smaller individuals on shore. There was an
overall growth trend. In Dec. 2015, two big individuals (prosomal width 89.27
mm and 98.89 mm) were recorded only while it could not represent the major
population. From Dec. 2015 to Mar. 2016, the number of individual was very few
in ST that no boxplot could be produced. In Jun. 2016, the prosomal width of major
population ranged 50-70 mm. But it dropped clearly to 30-40 mm in Sep. 2016
followed by an increase to 40-50 mm in Dec. 2016, 40-70 mm in Mar. 2017 and
50-60mm in Jun. 2017 (present survey). Based on overall higher number of small
individuals from Jun. 2016 to Jun. 2017, it indicated new round of spawning.
Throughout the monitoring period, the larger juveniles ranged 60-80 mm in
prosomal width. Juveniles reaching this size would gradually migrate to
sub-tidal habitats.
6.5.22
As a
summary for horseshoe crab populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014
to 2016 while the spawning time should be in spring. There were consistent,
increasing trends of population size in these two sampling zones. For Tachypleus tridentatus, small
individuals were rarely found in both zones from 2014 to 2015. It was believed
no occurrence of successful spawning. The existing individuals (that recorded
since 2012) grew to a mature size and migrated to sub-tidal habitat. Hence the
number of individuals decreased gradually. In 2016, new round of spawning was
recorded in ST while increasing number of individuals and body size was
noticed.
Impact
of the HKLR project
6.5.23
It was the 19th survey of the EM&A
programme during the construction period. Based on the results, impact of the
HKLR project could not be detected on horseshoe crabs. The population change
was mainly determined by seasonal variation while new rounds of spawning were
observed for both species. In case, abnormal phenomenon (e.g. very few numbers
of horseshoe crab individuals in wet season, large number of dead individuals
on the shore) is found, it would be reported as soon as possible.
Seagrass Beds
6.5.24
In the present survey, seagrass species Halophila
ovalis and Zostera japonica were recorded in TC3 and ST. Photo records were
shown in Figure 3.8 of Appendix I while the
complete records of seagrass beds survey were shown in Annex III of Appendix I.
6.5.25
Table 3.2 of Appendix I summarizes the
results of seagrass beds survey. In TC3, two small patches of Halophila ovalis was found in soft mud
area at 0.5-1.0 m above C.D. while the total seagrass bed area and vegetation
coverage were about 140.4 m2 (average seagrass bed area 70.2 m2)
and 100% respectively.
6.5.26
In ST, two large patches of Halophila ovalis were found while the total seagrass bed area was
about 17046.5 m2. The largest patch was an extensive, horizontal
strand with area ~12334.4 m2 and vegetation coverage 80-100%,
located in the soft mud area at 0.5-2.0 m above C.D.. It had covered
significant portion of the mud flat area southward from TC3 boundary to ST
(i.e. western shore of Tung Chung Wan). At vicinity, there was another large
patch (4712.1 m2, coverage 80-100%), located in the sandy area at
1.0-2.0 m above C.D..
6.5.27
For Zostera
japonica, there was one, small horizontal strand in the sandy area nearby
the seaward mangrove. The seagrass bed area and vegetation coverage were 105.4
m2 and 100% respectively.
6.5.28 Since majority of seagrass bed was confined in ST,
the temporal change of both seagrass species was investigated in details.
Temporal variation of seagrass beds
6.5.29
Figure 3.9 of Appendix I shows the changes of estimated total area of
seagrass beds in ST along the sampling months. For Zostera japonica, it
was not recorded in the 1st and 2nd surveys of monitoring
programme. Seasonal recruitment of few, small patches (total seagrass area: 10
m2) was found in Mar. 2013 that grew within the large patch of
seagrass Halophila ovalis. Then the patch size increased and merged
gradually with the warmer climate from Mar. to Jun. 2013 (15 m2).
However, the patch size decreased and remained similar from Sep. 2013 (4 m2)
to Mar. 2014 (3 m2). In Jun. 2014, the patch size increased
obviously again (41 m2) with warmer climate followed by a decrease
between Sep. 2014 (2 m2) and Dec. 2014 (5 m2). From Mar.
to Jun. 2015, the patch size increased sharply again (90 m2). It
might be due to the disappearance of the originally dominant seagrass Halophila
ovalis resulting in less competition for substratum and nutrients. From
Sep.2015 to Jun.2016, it was found coexisting with seagrass Halophila ovalis
with steady increasing patch size (from 44 m2 to 115 m2)
and variable coverage. In Sep. 2016, the patch size decreased again to (38 m2)
followed by an increase to a horizontal strand (105.4 m2) in Jun.
2017 (present survey). And it was no longer co-existing with Halophila
ovalis. Between Sep. 2014 and Jun. 2017, an increasing trend was noticed from
Sep. to Jun. of next year followed by a rapid decline in Sep. of next year. It
was possibly the causes of heat stress, typhoon and stronger grazing pressure
during wet season.
6.5.30
For Halophila ovalis, it was recorded as 3-4 medium to large
patches (area 18.9-251.7 m2; vegetation coverage 50-80%) beside the
mangrove vegetation at tidal level 2 m above C.D. in Sep. 2012 (first survey).
The total seagrass bed area grew steadily from 332.3 m2 in Sep. 2012
to 727.4 m2 in Dec. 2013. Flowers were observed in the largest patch
during its flowering period. In Mar. 2014, 31 small to medium patches were
newly recorded (variable area 1-72 m2 per patch, vegetation coverage
40-80% per patch) in lower tidal zone between 1.0 and 1.5 m above C.D. The
total seagrass area increased further to 1350 m2. In Jun. 2014,
these small and medium patches grew and extended to each other. These patches
were no longer distinguishable and were covering a significant mudflat area of
ST. It was generally grouped into 4 large patches (1116 ¡V 2443 m2)
of seagrass beds characterized of patchy distribution, variable vegetable
coverage (40-80%) and smaller leaves. The total seagrass bed area increased
sharply to 7629 m2. In Sep. 2014, the total seagrass area declined
sharply to 1111 m2. There were only 3-4 small to large patches
(6-253 m2) at high tidal level and 1 patch at low tidal level (786 m2).
Typhoon or strong water current was a possible cause (Fong, 1998). In Sep.
2014, there were two tropical cyclone records in Hong Kong (7th-8th
Sep.: no cyclone name, maximum signal number 1; 14th-17th
Sep.: Kalmaegi, maximum signal number 8SE) before the seagrass survey dated
21st Sep. 2014. The strong water current caused by the cyclone, Kalmaegi
especially, might have given damage to the seagrass beds. In addition, natural
heat stress and grazing force were other possible causes reducing seagrass beds
area. Besides, very small patches of Halophila ovalis could be found in
other mud flat area in addition to the recorded patches. But it was hardly
distinguished due to very low coverage (10-20%) and small leaves.
6.5.31
In Dec. 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.10 of Appendix I shows the
difference of the original seagrass beds area nearby the mangrove vegetation at
high tidal level between Jun. 2014 and Dec. 2014. Such rapid loss would not be
seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m
above C.D.) were present and normal in December 2012 and 2013. According to
Fong (1998), similar incident had occurred in ST in the past. The original
seagrass area had declined significantly during the commencement of the
construction and reclamation works for the international airport at Chek Lap
Kok in 1992. The seagrass almost disappeared in 1995 and recovered gradually
after the completion of reclamation works. Moreover, incident of rapid loss of
seagrass area was also recorded in another intertidal mudflat in Lai Chi Wo in
1998 with unknown reason. Hence Halophila ovalis was regarded as a
short-lived and r-strategy seagrass that could colonize areas in short period
but disappears quickly under unfavorable conditions (Fong, 1998).
Unfavourable conditions to seagrass Halophila ovalis
6.5.32
Typhoon or strong
water current was suggested as one unfavourable condition to Halophila ovalis (Fong, 1998). As
mentioned above, there were two tropical cyclone records in Hong Kong in Sep.
2014. The strong water current caused by the cyclones might have given damage
to the seagrass beds.
6.5.33 Prolonged light deprivation due to turbid water
would be another unfavorable condition. Previous studies reported that Halophila
ovalis had little tolerance to light deprivation. During experimental
darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died
completely after 30 days. The rapid death might be due to shortage of available
carbohydrate under limited photosynthesis or accumulation of phytotoxic end
products of anaerobic respiration (details see Longstaff et al., 1999).
Hence the seagrass bed of this species was susceptible to temporary light
deprivation events such as flooding river runoff (Longstaff and Dennison,
1999).
6.5.34 In order to
investigate any deterioration of water quality (e.g. more turbid) in ST, the
water quality measurement results at two closest monitoring stations SR3 and
IS5 of the EM&A programme were obtained from the water quality monitoring
team. Based on the results from June to December 2014, the overall water
quality was in normal fluctuation except there was one exceedance of suspended
solids (SS) at both stations in September. On 10th Sep., 2014, the
SS concentrations measured during mid-ebb tide at stations SR3 (27.5 mg/L) and
IS5 (34.5 mg/L) exceeded the Action Level (≤23.5 mg/L and 120% of upstream
control station¡¦s reading) and Limit Level (≤34.4 mg/L and 130% of upstream
control station¡¦s reading) respectively. The turbidity readings at SR3 and IS5
reached 24.8-25.3 NTU and 22.3-22.5 NTU respectively. The temporary turbid
water should not be caused by the runoff from upstream rivers. Because there
was no rain or slight rain from 1st to 10th Sep. 2014 (daily total rainfall at
the Hong Kong International Airport: 0-2.1 mm; extracted from the
climatological data of Hong Kong Observatory). The effect of upstream runoff on
water quality should be neglectable in that period. Moreover, the exceedance of
water quality was considered unlikely to be related to the contract works of
HKLR according to the ¡¥Notifications of Environmental Quality Limits
Exceedances¡¦ provided by the respective environmental team. The respective
construction of seawall and stone column works, which possibly caused turbid
water, were carried out within silt curtain as recommended in the EIA report.
Moreover, there was no leakage of turbid water, abnormity or malpractice
recorded during water sampling. In general, the exceedance of suspended solids
concentration was considered to be attributed to other external factors, rather
than the contract works.
6.5.35 Based on the
weather condition and water quality results in ST, the co-occurrence of cyclone
hit and turbid waters in Sep. 2014 might have combined the adverse effects on Halophila ovalis that leaded to
disappearance of this short-lived and r-strategy seagrass species. Fortunately,
Halophila ovalis was a fast-growing
species (Vermaat et al., 1995).
Previous studies showed that the seagrass bed could be recovered to the
original sizes in 2 months through vegetative propagation after experimental
clearance (Supanwanid, 1996). Moreover, it was reported to recover rapidly in
less than 20 days after dugong herbivory (Nakaoka and Aioi, 1999). As
mentioned, the disappeared seagrass in ST in 1995 could recover gradually after
the completion of reclamation works for international airport (Fong, 1998). The
seagrass beds of Halophila ovalis
might recolonize the mudflat of ST through seed reproduction as long as there
was no unfavorable condition in the coming months.
Recolonization of seagrass beds
6.5.36
Figure
3.10 of Appendix
I
shows the recolonization of seagrass bed area in ST from Dec. 2014 to Jun.
2017. From Mar. to Jun. 2015, 2-3 small patches of Halophila ovalis were newly found coinhabiting with another
seagrass species Zostera japonica.
But its total patch area was still very low relative to the previous records.
The recolonization rate was low while cold weather and insufficient sunlight
were possible factors between Dec. 2014 and Mar. 2015. Moreover, it would need
to compete with seagrass Zostera japonica
for substratum and nutrient. Since Zostera
japonica had extended and had covered the original seagrass bed of Halophila ovalis at certain degree. From
Jun. 2015 to Mar. 2016, the total seagrass area of Halophila ovalis had increased rapidly from 6.8 m2 to
230.63 m2. It had recolonized its original patch locations and
covered Zostera japonica. In Jun. 2016,
the total seagrass area increased sharply to 4707.3 m2. Similar to
the previous records of Mar to Jun. 2014, the original patch area increased
further to a horizontally long strand. Another large seagrass beds colonized
the lower tidal zone (1.0-1.5 m above C.D.). In Sep. 2016, this patch extended
much and covered significant soft mud area of ST, resulting in sharp increase
of total area (24245 m2). It indicated the second extensive
colonization of this r-strategy
seagrass. In Dec. 2016, this extensive seagrass patch decreased in size and had
separated into few, undistinguishable patches. Moreover, the horizontal strand
nearby the mangrove vegetation decreased in size (Figure 3.10 of Appendix
I).
The total seagrass bed decreased to 12550 m2. In Mar. 2017, the
seagrass bed area remained stable (12438 m2) while the vegetation
coverage decreased clearly (20-50%). It was once predicted that the seagrass
bed area would continue to decrease, similar to the record in Sep-Dec. 2014.
However, it increased in both area (17046.5 m2) and vegetation
coverage (80-100%) in Jun. 2017 (present survey).
Impact of the HKLR project
6.5.37 It was the 19th
survey of the EM&A programme during the construction period. According to
the results of present survey, there was clear recolonization of both seagrass
species Halophila ovalis and Zostera japonica in ST. Hence the
negative impact of HKLR project on the seagrass was not significant. In case
unfavorable phenomenon (e.g. reduction of seagrass patch size, abnormal change
of leave color) is found persistent, it would be reported as soon as possible.
Intertidal Soft Shore Communities
6.5.38
Table 3.3 and Figure 3.11 of Appendix I show the types of substratum along the
horizontal transect at every tidal level in all sampling zones. The relative
distribution of different substrata was estimated by categorizing the
substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random
quadrats along the horizontal transect. The distribution of substratum types
varied among tidal levels and sampling zones:
¡P
In TC1, high percentages of ¡¥Gravels and Boulders¡¦
(70-80%) were recorded at all tidal levels. The minor substratum types were
'Sands' (20% at high and low tidal levels) and 'Soft mud' (10-20% at low and
mid tidal levels).
¡P
In TC2, the major substratum type was ¡¥Sands¡¦ (60%)
at high tidal level followed by 'Gravels and Boulders' (30%). The substratum
types were recorded evenly at mid tidal level ('Soft mud' 40%, 'Sands' 30%,
'Gravels and Boulders' 30%). At low tidal level, the major substratum type was
'Soft mud' (70%) followed by 'Gravels and Boulders' (20%)
¡P
In TC3, high percentages of ¡¥Sands¡¦ (90-100%) were
recorded at high and mid tidal levels. At low tidal level, the major substratum
type was ¡¥Gravels and Boulders¡¦ (90%).
¡P
In ST, high percentages of ¡¥Gravels and Boulders¡¦
(80-100%) were recorded at high and mid tidal levels. At low tidal level, the
substratum types were recorded evenly ('Sands' 40%, 'Soft mud' 30%, 'Gravels
and Boulders' 30%).
6.5.39
There
was neither consistent vertical nor horizontal zonation pattern of substratum
type in all sampling zones. Such heterogeneous variation should be caused by
different hydrology (e.g. wave in different direction and intensity) received
by the four sampling zones.
6.5.40
Table 3.4 of Appendix I lists the total abundance, density and number
of taxon of every phylum in this survey. A total of 16420 individuals were
recorded. Mollusca was clearly the most abundant phylum (total abundance 15648
ind., density 522 ind. m-2, relative abundance 95.3%). The second
and third abundant phyla were Arthropoda (578 ind., 19 ind. m-2,
3.5%) and Annelida (91 ind., 3 ind. m-2, 0.6%) respectively.
Relatively other phyla were very low in abundances (density ≤1 ind. m-2,
relative abundance ≤0.2%). Moreover, the most diverse phylum was Mollusca (40
taxa) followed by Arthropoda (14 taxa) and Annelida (11 taxa). There were 1-3
taxa recorded only for other phyla. The taxonomic resolution and complete list
of collected specimens are shown in Appendix IV and V respectively.
6.5.41
Table 3.5 of Appendix I shows the number of individual, relative
abundance and density of each phylum in every sampling zone. The total
abundance (2830-5517 ind.) varied among the four sampling zones while the phyla
distributions were similar. In general, Mollusca was the most dominant phylum
(no. of individuals: 2589-5336 ind.; relative abundance 91.5-97.0%; density
345-711 ind. m-2). Other phyla were much lower in number of
individuals. Arthropoda was the second abundant phylum (119-172 ind.; 2.2-5.8%;
16-23 ind. m-2). Annelida was the third abundant phylum in TC2 and
TC3 (33-40 ind.; 0.6-1.4%; 4-5 ind. m-2). Nemertea was relatively
common in TC2 (17 ind.; 0.6%; 2 ind. m-2). Relatively other phyla
were low in abundance in all sampling zones (≤ 0.5%).
Dominant species in every sampling zone
6.5.42 Table 3.6 of Appendix
I
lists the abundant species (relative abundance >10%) in every sampling zone.
In the present survey, most of the listed abundant species were of low to
moderate densities (50-250 ind. m-2). Few listed species of high or
very high density (> 250 ind. m-2) were regarded as dominant species. Other
listed species of lower density (< 50 ind. m-2) were regarded as
common species.
6.5.43 In TC1, the major substratum was ¡¥Gravels
and Boulders¡¦ at all tidal levels. The most abundant gastropod was Batillaria multiformis at moderate-high
densities (248-291 ind. m-2, relative abundance 35-50%) at high and
mid tidal levels. Another abundant gastropod Cerithidea djadjariensis was at moderate densities (84-155 ind. m-2,
12-26%) at all tidal levels. Gastropod Monodonta
labio (138-209 ind. m-2, 24-29%) and rock oyster Saccostrea cucullata (78-104 ind. m-2,
11-18%, attached on boulders) were at moderate densities at mid and low tidal
levels.
6.5.44 In TC2, gastropod Cerithidea djadjariensis (297 ind. m-2, 60 %) was
abundant at moderate-high density at high tidal level (major substratum: 'Sands')
followed by common gastropod Batillaria
multiformis (50 ind. m-2, 10 %). Moreover, gastropod Cerithidea djadjariensis was also
abundant at moderate density (164 ind. m-2, 42 %) at mid tidal level
(major substrata: 'Sands' and 'Soft mud') with common gastropod Batillaria zonalis (64 ind. m-2,
16 %) and rock oyster Saccostrea
cucullata (44 ind. m-2, 11 %). There was no clearly abundant species at low
tidal level (major substratum: 'Soft mud'). There were few common taxa at
low-moderate densities such as gastropods Cerithidea
djadjariensis (62 ind. m-2, 25 %), Batillaria zonalis (39 ind. m-2, 16 %), rock oyster Saccostrea cucullata (49 ind. m-2,
20 %) and barnacle Balanus amphitrite
(38 ind. m-2, 15 %, attached on boulders).
6.5.45 In TC3, the major substratum was ¡¥Sands¡¦ at both high and mid tidal
levels. Gastropod Cerithidea djadjariensis was dominant species of high
densities (412-444 ind. m-2, 53-57 %) followed by two abundant
gastropods Batillaria multiformis (142-185 ind. m-2, 18-24 %)
and Cerithidea cingulata (98-130 ind. m-2, 13-17 %). At low
tidal level (major substratum: ¡¥Gravels and Boulders¡¦), rock oyster Saccostrea
cucullata (265 ind. m-2, 40%) and gastropod Monodonta labio
(194 ind. m-2, 30%) were abundant at moderate densities.
6.5.46
In ST,
gastropod Batillaria multiformis was
abundant at moderate density (207 ind. m-2, 35 %) followed by Monodonta labio (143 ind. m-2,
24 %) and limpet Cellana toreuma (97
ind. m-2, 16 %) at high tidal level (major substratum: ¡¥Gravels and
Boulders¡¦). At mid tidal level (major substratum: ¡¥Gravels and Boulders¡¦),
there were gastropods Monodonta labio
(90 ind. m-2, 18 %), Cerithidea
djadjariensis (82 ind. m-2, 16 %) and rock oyster Saccostrea cucullata (88 ind. m-2,
18%) at low-moderate densities. No single species was clearly abundant at low
tidal level (major substrata: ¡¥Sands¡¦ and ¡¥Soft mud¡¦). The gastropod Cerithidea djadjariensis was at
low-moderate density (75 ind. m-2, 28 %) followed by common
gastropod Lunella coronata (42 ind. m-2,
16%) and rock oyster Saccostrea cucullata
(37 ind. m-2, 14%).
6.5.47
In
general, there was no consistent zonation pattern of species distribution
across all sampling zones and tidal levels. The species distribution should be
determined by the type of substratum primarily. In general, gastropods Cerithidea djadjariensis (total number
of individuals: 4746 ind., relative abundance 28.9%), Batillaria multiformis (3076 ind., 18.7%), Cerithidea cingulata (1015 ind., 6.2%) and Batillaria zonalis (519 ind., 3.2%) were the most commonly
occurring species on sandy and soft mud substrata. Rock oyster Saccostrea cucullata (1887 ind., 11.5%),
gastropods Monodonta labio (2181
ind., 13.3%) and Lunella coronata
(473 ind., 2.9%) were commonly occurring species inhabiting gravel and boulders
substratum.
Biodiversity and abundance of soft shore
communities
6.5.48
Table 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.
6.5.49
Among the sampling
zones, the mean species numbers (10-12 spp. 0.25 m-2) and J (0.6-0.7) were similar. The mean
densities of TC1 and TC3 (625-736 ind. m-2) were higher than TC2 and
ST (377-451 ind. m-2). Due to different density, the mean H¡¦ of ST (1.7) was higher than that of
TC1, TC2 (1.5) and TC3 (1.2).
6.5.50
Across the tidal
levels, there was no consistent difference of the mean species number and H' in all sampling zones. For the mean
density, there were generally decreasing trends in TC2, TC3 and ST from high to
low tidal level. For the mean J,
there was a slightly increasing trend from high to low tidal level in all
sampling zones.
6.5.51
Figures 3.12-3.15 of Appendix I show the temporal changes of mean species number,
mean density, H¡¦ and J at every tidal level and in every
sampling zone along the sampling months. In general, all the biological
parameters fluctuated seasonally throughout the monitoring period. Lower mean
species number and density were recorded in dry season (Dec.) but the mean H' and J fluctuated within a stable range.
6.5.52
Focusing on the
changes of mean density in ST, there were steady decreasing trends regardless
of tidal levels since the beginning of monitoring period. It might be an
unfavourable change that reflected environmental stresses. However, the mean
densities increased again from Dec. 2016 to Jun. 2017 (present survey). The
faunal populations were believed in recovery.
Impact of the
HKLR project
6.5.53
It was the 19th survey of the EM&A
programme during the construction period. Based on the results, impacts of the
HKLR project were not detected on intertidal soft shore community. In case of
other abnormal phenomena (e.g. rapid or consistent decline of fauna densities and
species number) are observed, it would be reported as soon as possible.
6.6.1
Chan, K.K., Caley, K.J., 2003. Sandy Shores, Hong
Kong Field Guides 4. The Department of Ecology & Biodiversity, The
University of Hong Kong. pp 117.
6.6.2
Dai, A.Y., Yang, S.L., 1991. Crabs of the China
Seas. China Ocean Press. Beijing.
6.6.3
Dong, Y.M., 1991. Fauna of ZheJiang Crustacea.
Zhejiang Science and Technology Publishing House. ZheJiang.
6.6.4
EPD, 1997. Technical Memorandum on Environmental
Impact Assessment Process (1st edition). Environmental Protection
Department, HKSAR Government.
6.6.5
Fauchald, K., 1977. The polychaete worms.
Definitions and keys to the orders, families and genera. Natural History Museum
of Los Angeles County, Science Series 28. Los Angeles, U.S.A..
6.6.6
Fong, C.W., 1998. Distribution of Hong Kong
seagrasses. In: Porcupine! No. 18.
The School of Biological Sciences, The University of Hong Kong, in
collaboration with Kadoorie Farm & Botanic Garden Fauna Conservation
Department, p10-12.
6.6.7
Li, H.Y., 2008. The Conservation of Horseshoe Crabs
in Hong Kong. MPhil Thesis, City University of Hong Kong, pp 277.
6.6.8
Longstaff, B.J., Dennison, W.C., 1999. Seagrass
survival during pulsed turbidity events: the effects of light deprivation on
the seagrasses Halodule pinifolia and
Halophila ovalis. Aquatic Botany 65
(1-4), 105-121.
6.6.9
Longstaff, 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.
6.6.10
Nakaoka, M., Aioi, K., 1999. Growth of seagrass Halophila ovalis at dugong trails
compared to existing within-patch variation in a Thailand intertidal flat.
Marine Ecology Progress Series 184, 97-103.
6.6.11
Pielou, E.C., 1966. Shannon¡¦s formula as a measure
of species diversity: its use and misuse. American Naturalist 100, 463-465.
6.6.12
Qi, Z.Y., 2004. Seashells of China. China Ocean
Press. Beijing, China.
6.6.13
Qin, H., Chiu, H., Morton, B., 1998. Nursery beaches
for Horseshoe Crabs in Hong Kong. In: Porcupine! No. 18. The School of
Biological Sciences, The University of Hong Kong, in collaboration with
Kadoorie Farm & Botanic Garden Fauna Conservation Department, p9-10.
6.6.14
Shannon, C.E., Weaver, W., 1963. The Mathematical
Theory of Communication. Urbana: University of Illinois Press, USA.
6.6.15
Shin, P.K.S., Li, H.Y., Cheung, S.G., 2009.
Horseshoe Crabs in Hong Kong: Current Population Status and Human Exploitation.
Biology and Conservation of Horseshoe Crabs (part 2), 347-360.
6.6.16
Supanwanid, C., 1996. Recovery of the seagrass Halophila ovalis after grazing by
dugong. In: Kuo, J., Philips, R.C., Walker, D.I., Kirkman, H. (eds), Seagrass
biology: Proc Int workshop, Rottenest Island, Western Australia. Faculty of
Science, The University of Western Australia, Nedlands, 315-318.
6.6.17
Vermaat, J.E., Agawin, N.S.R., Duarte, C.M.,
Fortes, M.D., Marba. N., Uri, J.S., 1995. Meadow maintenance, growth and
productivity of a mixed Philippine seagrass bed. Marine Ecology Progress Series
124, 215-225.
6.6.18
Yang, D.J, Sun, R.P., 1988. Polychaetous annelids
commonly seen from the Chinese waters (Chinese version). China Agriculture
Press, China.
7.1.1
Site
Inspections were carried out on a weekly basis to monitor the implementation of
proper environmental pollution control and mitigation measures for the Project.
During the reporting month, five site inspections were carried out on 1, 7 14, 21
and 30 June 2017.
7.1.2 A summary
of observations found during the site inspections and the follow up actions
taken by the Contractor are described in Table 7.1.
Table 7.1 Summary
of Environmental Site Inspections
Date of Audit
|
Observations
|
Actions Taken
by Contractor / Recommendation
|
Date of
Observations Closed
|
26 May 2017
|
1.
Waste was observed at S25.
2. Oil
stain was observed on the ground of S25.
3. Stagnant
water was observed at S25.
4. Waste
accumulated was observed at S25.
5. Silt
curtain with gap was observed at Portion X.
|
1.
The waste was removed from S25.
2.
The oil stain was removed from the ground of S25.
3.
The stagnant water was removed from S25.
4.
The accumulated waste was removed at S25.
5.
The silt curtain was properly maintained at Portion X.
|
1 Jun 2017
|
1 Jun 2017
|
1. Waste was
observed at HMA.
2. Waste was
scattered on the ground at N26.
3. Gaps of silt curtain were
observed at Portion X.
4. Concrete waste was observed on
the ground at S15.
5. A skip was overloaded with waste
at S15.
|
1.
The waste was removed from HMA.
2.
The waste was removed from N26.
3.
The gaps of silt curtain were closed at Portion X.
4.
The concrete waste was removed from S15.
5.
The waste was removed from S15.
|
7 Jun 2017
|
7 Jun 2017
|
1. Concrete
waste was observed at S15.
2. Gaps of
silt curtain were observed at Portion X.
3. A skip was
overloaded with waste at S15.
4. Dust
emission was observed during vehicle movement at S25.
5. Waste was
observed at N1.
|
1.
The concrete waste was removed from S15.
2.
The gaps of silt curtain were closed at Portion
X.
3.
The waste was removed from the overloaded skip at
S15.
4.
Water spraying was provided to suppress dust
emission caused by vehicle movement S25.
5. The waste was removed from N1.
|
14 Jun 2017
|
14 Jun 2017
|
1.
Exposed soil surface was observed
at N1.
2.
Gaps of silt curtain were
observed at Portion X.
3.
Wheels of dump truck was not
washed sufficiently and muddy tracks were observed at the entrance / exit of
S8.
4.
Waste was accumulated in
Ventilation Building.
5. Stockpile
of dusty material was not covered properly at N1.
|
1.
The exposed soil surface was hard-paved at N1.
2.
The gaps of silt curtain were closed at Portion
X.
3.
Sufficient wheel washing was provided for dump
trucks before leaving the site at S8. No muddy track was observed at the
entrance / exit of S8.
4.
The accumulated waste was removed from
Ventilation Building.
5.
The stockpile of dusty material was cover
properly at N1.
|
21 Jun 2017
|
21 Jun 2017
|
1.
Waste was observed at N1.
2.
Stagnant water was observed at
HMA.
3.
More than 20 bags of cement were observed
without properly cover at HMA.
4.
Gaps of silt curtain were observed at Portion X.
|
1.
The waste was removed from N1.
2.
The stagnant water was removed from HMA.
3.
The cement bags were removed from HMA.
4.
The gaps of silt curtain were closed at Portion
X.
|
30 Jun 2017
|
30 Jun 2017
|
1.
Silt curtain with gap was
observed at Portion X.
2.
Oil drum was observed without
drip tray at N26.
3.
Concrete waste was observed at
N26.
4.
Wastewater treatment facility was not connected
properly at N26.
5.
Waste was not properly collected by using waste
separation facilities at N26.
6.
Stagnant water was observed at N26.
7.
Inadequate wheel washing facility was observed at
N26.
|
The Contractor was
recommended to:
1.
Maintain
the silt curtain properly at Portion X.
2. Provide drip tray for the oil drum or remove it immediately from N26.
3. Remove the concrete waste from N26.
4. Connect the wastewater treatment facility properly at N26.
5. Provide waste separation facilities at N26.
6. Remove the stagnant water at N26.
7.
Provide
adequate wheel washing facility at N26.
|
Follow-up actions for the observations
issued for the last weekly site inspection of the reporting month will be
inspected during the next site inspections
|
7.1.3 The
Contractor has rectified most of the observations as identified during
environmental site inspections within the reporting month. Follow-up actions
for outstanding observations will be inspected during the next site
inspections.
7.2
Advice on the Solid and Liquid Waste
Management Status
7.2.1 The
Contractor registered as a chemical waste producer for the Project. Sufficient
numbers of receptacles were available for general refuse collection and
sorting.
7.2.2 Monthly
summary of waste flow table is detailed in Appendix
J.
7.2.3
The
Contractor was reminded that chemical waste containers should be properly
treated and stored temporarily in designated chemical waste storage area on
site in accordance with the Code of Practice on the Packaging, Labelling and
Storage of Chemical Wastes.
7.3.1
The valid environmental licenses and permits
during the reporting month are summarized in Appendix
L.
7.4
Implementation
Status of Environmental Mitigation Measures
7.4.1 In
response to the site audit findings, the Contractors have rectified most of the observations as
identified during environmental site inspections during the reporting month.
Follow-up actions for outstanding observations will be inspected during the
next site inspections.
7.4.2 A summary
of the Implementation Schedule of Environmental Mitigation Measures (EMIS) is
presented in Appendix
M. Most of the
necessary mitigation measures were implemented properly.
7.4.3
Regular
marine travel route for marine vessels were implemented properly in accordance
to the submitted plan and relevant records were kept properly.
7.4.4
Dolphin
Watching Plan was implemented during the reporting month. No dolphins inside
the silt curtain were observed. The relevant records were kept properly.
7.5.1
No Action and Limit
Level exceedances of 1-hr TSP and 24-hr TSP were recorded at AMS5 and AMS6
during the reporting month.
7.5.2
For
construction noise, no Action and Limit Level exceedances were recorded at the
monitoring station during the reporting month.
7.5.1
For
marine water quality monitoring, no Action Level and Limit Level exceedances
of dissolved
oxygen, turbidity and suspended solid levels were recorded by the ET of
Contract No. HY/2010/02 and Contract No. HY/2011/09 during the reporting month.
7.6
Summary of Complaints, Notification of
Summons and Successful Prosecution
7.6.1
For
Environmental Complaint No. COM-2017-095(3) mentioned in previously Monthly
EM&A Report for May 2017, it was considered that the complaint was likely
related to Contract No. HY/2011/03. The Contractor has implemented the
following measures to minimize the potential noise impact:
-
Additional
noise barriers have been erected in the active working area to further mitigate
the associated noise emissions as far as practicable;
-
Cover
the breaker tip with acoustic material;
-
Noise
barriers have been located as close as possible to the noise source. Also, gaps
and openings at joints in the barriers material have been minimized;
-
Speed
up of construction works in order to shorten the duration noise impact/nuisance
to the surrounding;
-
Minimize
the quantities of noisy plant as far as practicable; and
-
Regular
review of working duration and switch off all unnecessary machinery and plant.
7.6.2 There was no complaint received in relation
to the environmental impacts during the reporting period.
7.6.3
There
was no complaints received in relation to the environmental impacts during the
reporting month. The details of cumulative
statistics of Environmental Complaints are provided in Appendix K.
7.6.4 No
notification of summons and prosecution was received during the reporting
period. Statistics on notifications of summons and successful prosecutions are summarized in Appendix N.
8.1.1 As
informed by the Contractor, the
major construction activities for July 2017 are summarized in Table 8.1.
Table
8.1 Construction
Activities for July 2017
Site Area
|
Description of
Activities
|
WA7
|
Stockpiling
|
Portion X
|
Removal of toe
loading
|
Portion X
|
Dismantling/Trimming
of Temporary 40mm Stone Platform for Construction of Seawall
|
Portion X
|
Construction
of Seawall
|
Portion X
|
Loading and
Unloading of Filling Materials
|
Portion X
|
Backfilling at
Scenic Hill Tunnel (Cut & Cover Tunnel)
|
Portion X
|
Excavation for
HKBCF to Airport Tunnel & Construction of Tunnel Box structure
|
Portion X
|
Excavation for
Diversion of Culvert PR14
|
Airport Road
|
Works for
Diversion of Airport Road
|
Airport Road /
Airport Express Line / East Coast Road
|
Utilities
Detection
|
Airport Road /
Airport Express Line/ East Coast Road
|
Establishment
of Site Access
|
Shaft 3
Extension North Shaft
|
Construction
of Tunnel Box Structure
|
Airport Road
|
Excavation and
Lateral Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel West (Cut & Cover Tunnel)
|
Portion X
|
Excavation and
Lateral Support Works & Construction of Tunnel Box Structure for HKBCF to
Airport Tunnel East (Cut & Cover Tunnel)
|
Portion X
|
Sub-structure
& Superstructure Works for Highway Operation and Maintenance Area
Building
|
West Portal
|
Superstructure
Works for Scenic Hill Tunnel West Portal Ventilation building
|
8.2
Environmental Monitoring Schedule for
the Coming Month
8.2.1
The
tentative schedule for environmental monitoring in July 2017 is provided in Appendix D.
9.1.1 The
construction phase and EM&A programme of the Contract commenced on 17
October 2012. This
is the fifty-seventh Monthly EM&A report for the Contract which summarizes
the monitoring results and audit findings of the EM&A programme during the
reporting period from 1 to 30 June 2017.
Air Quality
9.1.2 No Action and Limit Level exceedances of 1-hr TSP and 24-hr TSP were
recorded at AMS5 and AMS6 during the reporting month.
Noise
9.1.3 For
construction noise, no Action and Limit Level exceedances were recorded at the
monitoring station during the reporting month.
Water Quality
9.1.4
For
marine water quality monitoring, no Action Level and Limit Level exceedances
of dissolved
oxygen, turbidity and suspended solid levels were recorded by the ET of
Contract No. HY/2010/02 and Contract No. HY/2011/09 during the reporting month.
Dolphin
9.1.5 During the June¡¦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.
9.1.6
Due to monthly variation in dolphin occurrence
within the study area, it would be more appropriate to draw conclusion on
whether any impacts on dolphins have been detected related to the construction
activities of this project in the quarterly EM&A report, where comparison
on distribution, group size and encounter rates of dolphins between the
quarterly impact monitoring period (June 2017 ¡V August 2017) and baseline
monitoring period (3-month period) will be made.
Mudflat
9.1.7 This
measurement result was generally and relatively higher than the baseline
measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.
9.1.8
The
June 2017 survey results indicate that the impacts of the HKLR project
could not be detected on horseshoe crabs and intertidal soft shore community. There was clear
recolonization of both seagrass species Halophila
ovalis and Zostera japonica in
ST. Hence, the negative impact of HKLR project on the seagrass was not
significant.
Environmental Site
Inspection and Audit
9.1.9
Environmental
site inspections were carried out on 1, 7, 14, 21 and 30 June 2017.
Recommendations on remedial actions were given to the Contractors for the
deficiencies identified during the site inspections.
9.1.10
For
Environmental Complaint No. COM-2017-095(3) mentioned in previously Monthly
EM&A Report for May 2017, it was considered that the complaint was likely
related to Contract No. HY/2011/03.
9.1.11
There
was no received in relation to the environmental impact during the reporting
period.
9.1.12
No
notification of summons and prosecution was received during the reporting
period.