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 Hong Kong Limited has been appointed by the Contractor to implement the Environmental Monitoring & Audit (EM&A) programme for the Contract in accordance with the Updated EM&A Manual for HKLR (Version 1.0) and will be providing environmental team services to the Contract.

This is the seventy-fifth Monthly EM&A report for the Contract which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 to 31 December 2018.

Environmental Monitoring and Audit Progress

The monthly EM&A programme was undertaken in accordance with the Updated EM&A Manual for HKLR (Version 1.0). A summary of the monitoring activities during this reporting month is listed below:

1-hr TSP Monitoring	5, 11, 17, 21, 27 and 31 December 2018
24-hr TSP Monitoring Noise Monitoring	4, 10, 14, 20, 24 and 28 December 2018 5, 11, 19, 27 and 31 December 2018
Water Quality Monitoring	3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26, 28 and 31 December 2018
Chinese White Dolphin Monitoring Mudflat Monitoring(Ecology) Mudflat Monitoring (Sedimentation rate)	3, 5, 10 and 12 December 2018 1, 2, 11, 15 and 16 December 2018 1 December 2018
Site Inspection	5, 12, 19 and 28 December 2018

Breaches of Action and Limit Levels

A summary of environmental exceedances for this reporting month is as follows:

Environmental Monitoring	Parameters	Action Level (AL)	Limit Level (LL)
Air Quality	1-hr TSP	0	0
Air Quality	24-hr TSP	0	0
Noise	L_{eq (30 min)}	0	0
Water Quality	Suspended solids level (SS)	2	0
	Turbidity level	0	0
	Dissolved oxygen level (DO)	0	0

Complaint Log

There was one complaint received in relation to the environmental impacts during this reporting month.

Notifications of Summons and Prosecutions

There were no notifications of summons or prosecutions received during this reporting month.

Reporting Changes

This report has been developed in compliance with the reporting requirements for the subsequent EM&A reports as required by the Updated EM&A Manual for HKLR (Version 1.0).

The proposal for the change of Action Level and Limit Level for suspended solid and turbidity was approved by EPD on 25 March 2013.

The revised Event and Action Plan for dolphin monitoring was approved by EPD on 6 May 2013.

The original monitoring station at IS(Mf)9 (Coordinate: 813273E, 818850N) was observed inside the perimeter silt curtain of Contract HY/2010/02 on 1 July 2013, as such the original impact water quality monitoring location at IS(Mf)9 was temporarily shifted outside the silt curtain. As advised by the Contractor of HY/2010/02 in August 2013, the perimeter silt curtain was shifted to facilitate safe anchorage zone of construction barges/vessels until end of 2013 subject to construction progress. Therefore, water quality monitoring station IS(Mf)9 was shifted to 813226E and 818708N since 1 July 2013. According to the water quality monitoring team��s observation on 24 March 2014, the original monitoring location of IS(Mf)9 was no longer enclosed by the perimeter silt curtain of Contract HY/2010/02. Thus, the impact water quality monitoring works at the original monitoring location of IS(Mf)9 has been resumed since 24 March 2014.

Transect lines 1, 2, 7, 8, 9 and 11 for dolphin monitoring have been revised due to the obstruction of the permanent structures associated with the construction works of HKLR and the southern viaduct of TM-CLKL, as well as provision of adequate buffer distance from the Airport Restricted Areas. The EPD issued a memo and confirmed that they had no objection on the revised transect lines on 19 August 2015.

The water quality monitoring stations at IS10 (Coordinate: 812577E, 820670N) and SR5 (811489E, 820455N) are located inside Hong Kong International Airport (HKIA) Approach Restricted Areas. The previously granted Vessel's Entry Permit for accessing stations IS10 and SR5 were expired on 31 December 2016. During the permit renewing process, the water quality monitoring location was shifted to IS10(N) (Coordinate: 813060E, 820540N) and SR5(N) (Coordinate: 811430E, 820978N) on 2, 4 and 6 January 2017 temporarily. The permit has been granted by Marine Department on 6 January 2017. Thus, the impact water quality monitoring works at original monitoring location of IS10 and SR5 has been resumed since 9 January 2017.

Transect lines 2, 3, 4, 5, 6 and 7 for dolphin monitoring have been revised and transect line 24 has been added due to the presence of a work zone to the north of the airport platform with intense construction activities in association with the construction of the third runway expansion for the Hong Kong International Airport. The EPD issued a memo and confirmed that they had no objection on the revised transect lines on 28 July 2017. The alternative dolphin transect lines are adopted starting from August��s dolphin monitoring.

A new water quality monitoring team has been employed for carrying out water quality monitoring work for the Contract starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong International Airport into a Three-Runway System (3RS Project), original locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed by works boundary of 3RS Project. Alternative impact water quality monitoring stations, naming as CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and were adopted starting from 23 August 2017 to replace the original locations of water quality monitoring for the Contract.

The role and responsibilities as the ET Leader of the Contract was temporarily taken up by Mr Willie Wong instead of Ms Claudine Lee from 25 September 2017 to 31 December 2017.

Water quality monitoring station SR10A(N) (Coordinate: 823644E, 823484N) was unreachable on 4 October 2017 during flood tide as fishing activities were observed. As such, the water monitoring at station SR10A(N) was conducted at Coordinate: 823484E, 823593N during flood tide on 4 October 2017 temporarily.

The topographical condition of the water monitoring stations SR3 (Coordinate: 810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A (Coordinate: 823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot be accessed safely for undertaking water quality monitoring. The water quality monitoring has been temporarily conducted at alternative stations, namely SR3(N) (Coordinate 810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and SR10A(N) (Coordinate: 823644E, 823484N) since 1 September 2017. The water quality monitoring at station SR10B was temporarily conducted at Coordinate: 823683E, 823187N on 1, 4, 6, 8 September 2017 and has been temporarily fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E, 823159N) since 11 September 2017. Proposal for permanently relocating the aforementioned stations was approved by EPD on 8 January 2018.

According to latest information received in July 2018, the works area WA7 was handed over to other party on 28 February 2018 instead of 31 January 2018.

The future key issues include potential noise, air quality, water quality and ecological impacts and waste management arising from the following construction activities to be undertaken in the upcoming month:

�P Dismantling/ trimming of Temporary 40mm Stone Platform for Construction of Seawall at Portion X;

�P Construction of Seawall at Portion X;

�P Loading and Unloading Filling Materials at Portion X;

�P Backfilling at Scenic Hill Tunnel (Cut & Cover Tunnel) at Portion X;

�P Works for Diversion of Airport Road;

�P Establishment of Site Access at Airport Road / Airport Express Line/ East Coast Road;

�P Finishing Works for Highway Operation and Maintenance Area Building at Portion X; and

�P Finishing Works for Scenic Hill Tunnel West Portal Ventilation building at West Portal.

1 Introduction

1.1 Basic Project Information

1.1.1 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).

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. The works area WA7 was handed over to other party on 28 February 2018. Figure 1.1 shows the project site boundary. The works areas are shown in Appendix O.

1.1.4 The Contract includes the following key aspects:

�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.

1.1.5 This is the seventy-fifth Monthly EM&A report for the Contract which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 to 31 December 2018.

1.1.6 BMT Hong Kong Limited has been appointed by the Contractor to implement the EM&A programme for the Contract in accordance with the Updated EM&A Manual for HKLR (Version 1.0) for HKLR and will be providing environmental team services to the Contract. Ramboll Hong Kong Limited was employed by HyD as the Independent Environmental Checker (IEC) and Environmental Project Office (ENPO) for the Project. The project organization with regard to the environmental works is as follows.

1.2 Project Organisation

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 Hong Kong Limited)	Environmental Project Office Leader	Y. H. Hui	3465 2888	3465 2899
	Independent Environmental Checker	Antony Wong (See Remark 1)	3465 2888	3465 2899
Contractor (China State Construction Engineering (Hong Kong) Ltd)	Project Manager	S. Y. Tse	3968 7002	2109 2588
	Environmental Officer	Federick Wong	3968 7117	2109 2588
Environmental Team (BMT Hong Kong Limited)	Environmental Team Leader	Claudine Lee	2241 9847	2815 3377
24 hours complaint hotline	---	---	5699 5730	---
Remark: (1) Mr. Ray Yan has taken up the role of Independent Environmental Checker staring from 1 January 2019.

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
Dismantling/trimming of temporary 40mm stone platform for construction of seawall	Portion X
Construction of seawall	Portion X
Loading and unloading of filling materials	Portion X
Backfilling at Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Works for diversion	Airport Road
Establishment of site access	Airport Road/ Airport Express Line/ East Coast Road
Finishing works for Highway Operation and Maintenance Area Building	Portion X
Finishing works for Scenic Hill Tunnel West Portal Ventilation building	West Portal

2 Air Quality Monitoring

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	500

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 Monitoring Equipment

2.2.1 24-hour TSP air quality monitoring was performed using High Volume Sampler (HVS) located at each designated monitoring station. The HVS meets all the requirements of the Contract Specific EM&A Manual. Portable direct reading dust meters were used to carry out the 1-hour TSP monitoring. Brand and model of the equipment is given in Table 2.3.

Table 2.3 Air Quality Monitoring Equipment

Equipment	Brand and Model
Portable direct reading dust meter (1-hour TSP)	Sibata Digital Dust Indicator (Model No. LD-5R)
High Volume Sampler (24-hour TSP)	Tisch Environmental Mass Flow Controlled Total Suspended Particulate (TSP) High Volume Air Sampler (Model No. TE-5170)

2.3 Monitoring Locations

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 Monitoring Parameters, Frequency and Duration

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 Monitoring Methodology

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 ��2.5% deviation over 24-hour sampling period.

(b) Preparation of Filter Papers

(i) Glass fibre filters, G810 were labelled and sufficient filters that were clean and without pinholes were selected.

(ii) All filters were equilibrated in the conditioning environment for 24 hours before weighing. The conditioning environment temperature was around 25 �XC and not variable by more than ��3 �XC; the relative humidity (RH) was < 50% and not variable by more than ��5%. A convenient working RH was 40%.

(iii) All filter papers were prepared and analysed by ALS Technichem (HK) Pty Ltd., which is a HOKLAS accredited laboratory and has comprehensive quality assurance and quality control programmes.

(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 Monitoring Schedule for the Reporting Month

2.6.1 The schedule for air quality monitoring in December 2018 is provided in Appendix D.

2.7 Monitoring Results

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	71	42 �V 109	352	500
AMS6	66	37 �V 93	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	53	36 �V 83	164	260
AMS6	62	41 �V 83	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 Noise Monitoring

3.1 Monitoring Requirements

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 Monitoring Equipment

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 Monitoring Locations

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 Monitoring Parameters, Frequency and Duration

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). L_eq, L₁₀ and L₉₀ would be recorded.	At least once per week

3.5 Monitoring Methodology

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.

(i) frequency weighting: A

(ii) time weighting: Fast

(iii) time measurement: L_{eq(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 L_eq, 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.

3.6 Monitoring Schedule for the Reporting Month

3.6.1 The schedule for construction noise monitoring in December 2018 is provided in Appendix D.

3.7 Monitoring Results

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 L_{eq (30 mins)}, dB(A)	Range of L_{eq (30 mins)}, dB(A)	Limit Level L_{eq (30 mins)}, dB(A)
NMS5	62	59 �V 65	75

*A correction factor of +3dB(A) from free field to facade measurement was included.

3.7.2 There were no Action and Limit Level exceedances for noise during daytime on normal weekdays of the reporting month.

3.7.3 The event action plan is annexed in Appendix F.

4 Water Quality Monitoring

4.1 Monitoring Requirements

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
Dissolved Oxygen (mg/L) (surface, middle and bottom)	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 Monitoring Equipment

4.2.1 Table 4.2 summarizes the equipment used in the impact water quality monitoring programme.

Table 4.2 Water Quality Monitoring Equipment

Equipment	Brand and Model
DO and Temperature Meter, Salinity Meter, Turbidimeter and pH Meter	YSI Model 6820
Positioning Equipment	JRC DGPS 224 Model JLR-4341 with J-NAV 500 Model NWZ4551
Water Depth Detector	Eagle Cuda-168 and Lowrance x-4
Water Sampler	Kahlsio Water Sampler (Vertical) 2.2 L with messenger

4.3 Monitoring Parameters, Frequency and Duration

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 �� 1.75 hour of the predicted time)

(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 Monitoring Locations

4.4.1 In accordance with the Contract Specific EM&A Manual, thirteen stations (6 Impact Stations, 5 Sensitive Receiver Stations and 2 Control Stations) were designated for impact water quality monitoring. The six Impact Stations (IS) were chosen on the basis of their proximity to the reclamation and thus the greatest potential for water quality impacts, the five Sensitive Receiver Stations (SR) were chosen as they are close to the key sensitive receives and the two Control Stations (CS) were chosen to facilitate comparison of the water quality of the IS stations with less influence by the Project/ ambient water quality conditions.

4.4.2 A new water quality monitoring team has been employed for carrying out water quality monitoring work for the Contract starting from 23 August 2017. Due to marine work of the Expansion of Hong Kong International Airport into a Three-Runway System (3RS Project), original locations of water quality monitoring stations CS2, SR5 and IS10 are enclosed by works boundary of 3RS Project. Alternative impact water quality monitoring stations, naming as CS2(A), SR5(N) and IS10(N) was approved on 28 July 2017 and were adopted starting from 23 August 2017 to replace the original locations of water quality monitoring for the Contract.

4.4.3 The topographical condition of the water monitoring stations SR3 (Coordinate: 810525E, 816456N), SR4 (Coordinate: 814760E, 817867N), SR10A (Coordinate: 823741E, 823495N) and SR10B (Coordinate: 823686E, 823213N) cannot be accessed safely for undertaking water quality monitoring. The water quality monitoring has been temporarily conducted at alternative stations, namely SR3(N) (Coordinate 810689E, 816591N), SR4(N) (Coordinate: 814705E, 817859N) and SR10A(N) (Coordinate: 823644E, 823484N) since 1 September 2017. The water quality monitoring at station SR10B was temporarily conducted at Coordinate: 823683E, 823187N on 1, 4, 6, 8 September 2017 and has been temporarily fine-tuned to alternative station SR10B(N2) (Coordinate: 823689E, 823159N) since 11 September 2017. Proposal for permanently relocating the aforementioned stations was approved by EPD on 8 January 2018.

4.4.4 The locations of water quality monitoring stations during the reporting period are summarized in Table 4.4 and shown in Figure 2.1.

Table 4.4 Impact Water Quality Monitoring Stations

Monitoring Stations	Description	Coordinates
Monitoring Stations	Description	Easting	Northing
IS5	Impact Station (Close to HKLR construction site)	811579	817106
IS(Mf)6	Impact Station (Close to HKLR construction site)	812101	817873
IS7	Impact Station (Close to HKBCF construction site)	812244	818777
IS8	Impact Station (Close to HKBCF construction site)	814251	818412
IS(Mf)9	Impact Station (Close to HKBCF construction site)	813273	818850
IS10(N)	Impact Station (Close to HKBCF construction site)	812942	820881
SR3(N)	Sensitive receivers (San Tau SSSI)	810689	816591
SR4(N)	Sensitive receivers (Tai Ho Inlet)	814705	817859
SR5(N)	Sensitive Receivers (Artificial Reef in NE Airport)	812569	821475
SR10A(N)	Sensitive receivers (Ma Wan Fish Culture Zone)	823644	823484
SR10B(N2)	Sensitive receivers (Ma Wan Fish Culture Zone)	823689	823159
CS2(A)	Control Station (Mid-Ebb)	805232	818606
CS(Mf)5	Control Station (Mid-Flood)	817990	821129
Remarks: 1) A vessel moored at IS10(N) during ebb tide monitoring period on 5 Dec 2018. The water quality monitoring at station IS10(N)(coordinate: 820881N, 812942E) was temporarily conducted at a location which is close to the original coordinates of station IS10(N) as far as practicable based on safety consideration during ebb tide on 5 Dec 2018. 2) Metal beam across Tai Ho Inlet blocked the access of station SR4(N)(coordinates: 817859N, 814705E) in all water monitoring date of December 2018. Also, a rope connecting silt curtains in the sea on 10, 12 and 14 December 2018 and silt curtains deployment on 17 Dec 2018 were observed respectively. The access to SR4(N) have been further blocked by silt curtains since 17 Dec 2018. As such, the water quality monitoring at station SR4(N) was temporarily conducted at a location which is close to the original coordinates of station SR4(N) as far as practicable in December 2018.

4.5 Monitoring Methodology

4.5.1 Instrumentation

(a) The in-situ water quality parameters including dissolved oxygen, temperature, salinity and turbidity, pH were measured by multi-parameter meters.

4.5.2 Operating/Analytical Procedures

(a) Digital Differential Global Positioning Systems (DGPS) were used to ensure that the correct location was selected prior to sample collection.

(b) Portable, battery-operated echo sounders were used for the determination of water depth at each designated monitoring station.

(c) All in-situ measurements were taken at 3 water depths, 1 m below water surface, mid-depth and 1 m above sea bed, except where the water depth was less than 6 m, in which case the mid-depth station was omitted. Should the water depth be less than 3 m, only the mid-depth station was monitored.

(d) At each measurement/sampling depth, two consecutive in-situ monitoring (DO concentration and saturation, temperature, turbidity, pH, salinity) and water sample for SS. The probes were retrieved out of the water after the first measurement and then re-deployed for the second measurement. Where the difference in the value between the first and second readings of DO or turbidity parameters was more than 25% of the value of the first reading, the reading was discarded and further readings were taken.

(e) Duplicate samples from each independent sampling event were collected for SS measurement. Water samples were collected using the water samplers and the samples were stored in high-density polythene bottles. Water samples collected were well-mixed in the water sampler prior to pre-rinsing and transferring to sample bottles. Sample bottles were pre-rinsed with the same water samples. The sample bottles were then be packed in cool-boxes (cooled at 4^oC without being frozen), and delivered to ALS Technichem (HK) Pty Ltd. for the analysis of suspended solids concentrations. The laboratory determination work would be started within 24 hours after collection of the water samples. ALS Technichem (HK) Pty Ltd. is a HOKLAS accredited laboratory and has comprehensive quality assurance and quality control programmes.

(f) The analysis method and detection limit for SS is shown in Table 4.5.

Table 4.5 Laboratory Analysis for Suspended Solids

Parameters	Instrumentation	Analytical Method	Detection Limit
Suspended Solid (SS)	Weighting	APHA 2540-D	0.5mg/L

(g) Other relevant data were recorded, including monitoring location / position, time, water depth, tidal stages, weather conditions and any special phenomena or work underway at the construction site in the field log sheet for information.

4.5.3 Maintenance and Calibrations

(a) All in situ monitoring instruments would be calibrated by ALS Technichem (HK) Pty Ltd. before use and at 3-monthly intervals throughout all stages of the water quality monitoring programme. The procedures of performance check of sonde and testing results are provided in Appendix C.

4.6 Monitoring Schedule for the Reporting Month

4.6.1 The schedule for impact water quality monitoring in December 2018 is provided in Appendix D.

4.7 Monitoring Results

4.7.1 Impact water quality monitoring was conducted at all designated monitoring stations during the reporting month. Impact water quality monitoring results and relevant graphical plots are provided in Appendix E.

4.7.2 Water quality impact sources during water quality monitoring were the construction activities of the Contract, nearby construction activities by other parties and nearby operating vessels by other parties.

4.7.3 For marine water quality monitoring, no Action Level and Limit Level exceedances of dissolved oxygen level and turbidity level were recorded during the reporting month.

4.7.4 During the reporting month, two Action Level exceedances of suspended solids level were recorded. No Limit Level exceedances of suspended solids level were recorded.

4.7.5 Number of exceedances recorded during the reporting month at each impact station are summarized in Table 4.6.

Table 4.6 Summary of Water Quality Exceedances

Station	Exceedance Level	DO (S&M)		DO (Bottom)		Turbidity		SS		Total number of exceedances
Station	Exceedance Level	Ebb	Flood	Ebb	Flood	Ebb	Flood	Ebb	Flood	Ebb	Flood
IS5	Action Level	--	--	--	--	--	--	--	12-12-2018	0	1
IS5	Limit Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)6	Action Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)6	Limit Level	--	--	--	--	--	--	--	--	0	0
IS7	Action Level	--	--	--	--	--	--	--		0	0
IS7	Limit Level	--	--	--	--	--	--	--	--	0	0
IS8	Action Level	--	--	--	--	--	--	--	--	0	0
IS8	Limit Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)9	Action Level	--	--	--	--	--	--	--	12-12-2018	0	1
IS(Mf)9	Limit Level	--	--	--	--	--	--	--	--	0	0
IS10(N)	Action Level	--	--	--	--	--	--	--		0	0
IS10(N)	Limit Level	--	--	--	--	--	--	--	--	0	0
SR3(N)	Action Level	--	--	--	--	--	--	--	--	0	0
SR3(N)	Limit Level	--	--	--	--	--	--	--	--	0	0
SR4(N)	Action Level	--	--	--	--	--	--	--	--	0	0
SR4(N)	Limit Level	--	--	--	--	--	--	--	--	0	0
SR5(N)	Action Level	--	--	--	--	--	--	--	--	0	0
SR5(N)	Limit Level	--	--	--	--	--	--	--	--	0	0
SR10A(N)	Action Level	--	--	--	--	--	--	--	--	0	0
SR10A(N)	Limit Level	--	--	--	--	--	--	--	--	0	0
SR10B(N2)	Action Level	--	--	--	--	--	--	--	--	0	0
SR10B(N2)	Limit Level	--	--	--	--	--	--	--	--	0	0
Total	Action	0	0	0	0	0	0	0	2	2**
Total	Limit	0	0	0	0	0	0	0	0	0**

Notes:

S: Surface;

M: Mid-depth;

** The total number of exceedances

4.7.6 The exceedances suspended solid level recorded during reporting period were considered to be attributed to other external factors such as sea condition, rather than the contract works. Therefore, the exceedances were considered as non-contract related. Records of ��Notification of Environmental Quality Limit Exceedances�� are provided in Appendix N.

4.7.7 The event action plan is annexed in Appendix F.

5 Dolphin Monitoring

5.1 Monitoring Requirements

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.

5.2 Monitoring Methodology

Vessel-based Line-transect Survey

5.2.1 According to the requirement of the updated EM&A manual, dolphin monitoring programme should cover all transect lines in NEL and NWL survey areas (see Figure 1 of Appendix H) twice per month throughout the entire construction period. The co-ordinates of all transect lines are shown in Table 5.2. The coordinates of several starting and ending points have been revised due to the presence of a work zone to the north of the airport platform with intense construction activities in association with the construction of the third runway expansion for the Hong Kong International Airport. The EPD issued a memo and confirmed that they had no objection on the revised transect lines on 28 July 2017, and the revised coordinates are in red and marked with an asterisk in Table 5.2.

Table 5.2 Co-ordinates of Transect Lines

Line No.		Easting	Northing	Line No.		Easting	Northing
1	Start Point	804671	815456	13	Start Point	816506	819480
1	End Point	804671	831404	13	End Point	816506	824859
2	Start Point	805476	820800*	14	Start Point	817537	820220
2	End Point	805476	826654	14	End Point	817537	824613
3	Start Point	806464	821150*	15	Start Point	818568	820735
3	End Point	806464	822911	15	End Point	818568	824433
4	Start Point	807518	821500*	16	Start Point	819532	821420
4	End Point	807518	829230	16	End Point	819532	824209
5	Start Point	808504	821850*	17	Start Point	820451	822125
5	End Point	808504	828602	17	End Point	820451	823671
6	Start Point	809490	822150*	18	Start Point	821504	822371
6	End Point	809490	825352	18	End Point	821504	823761
7	Start Point	810499	822000*	19	Start Point	822513	823268
7	End Point	810499	824613	19	End Point	822513	824321
8	Start Point	811508	821123	20	Start Point	823477	823402
8	End Point	811508	824254	20	End Point	823477	824613
9	Start Point	812516	821303	21	Start Point	805476	827081
9	End Point	812516	824254	21	End Point	805476	830562
10	Start Point	813525	821176	22	Start Point	806464	824033
10	End Point	813525	824657	22	End Point	806464	829598
11	Start Point	814556	818853	23	Start Point	814559	821739
11	End Point	814556	820992	23	End Point	814559	824768
12	Start Point	815542	818807	24*	Start Point	805476*	815900*
12	End Point	815542	824882	24*	End Point	805476*	819100*

Note:
Co-ordinates in red and marked with asterisk are revised co-ordinates of transect line.

5.2.2 The survey team used standard line-transect methods (Buckland et al. 2001) to conduct the systematic vessel surveys, and followed the same technique of data collection that has been adopted over the last 20 years of marine mammal monitoring surveys in Hong Kong developed by HKCRP (see Hung 2017). For each monitoring vessel survey, a 15-m inboard vessel with an open upper deck (about 4.5 m above water surface) was used to make observations from the flying bridge area.

5.2.3 Two experienced observers (a data recorder and a primary observer) made up the on-effort survey team, and the survey vessel transited different transect lines at a constant speed of 13-15 km per hour. The data recorder searched with unaided eyes and filled out the datasheets, while the primary observer searched for dolphins and porpoises continuously through 7 x 50 Fujinon marine binoculars. Both observers searched the sea ahead of the vessel, between 270^o and 90^o (in relation to the bow, which is defined as 0^o). 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 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.

5.3 Monitoring Results

Vessel-based Line-transect Survey

5.3.1 During the month of December 2018, two sets of systematic line-transect vessel surveys were conducted on the 3^rd, 5^th, 10^th and 12^th 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 261.96 km of survey effort was collected, with 90.3% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility) (Annex I of Appendix H).

5.3.3 Among the two survey areas, 97.00 km and 164.96 km of survey effort were collected from NEL and NWL survey areas respectively. Moreover, the total survey effort conducted on primary lines was 193.46 km, while the effort on secondary lines was 68.50 km.

5.3.4 During the two sets of monitoring surveys in December 2018, two groups of six Chinese White Dolphins were sighted (see Annex II of Appendix H). Both dolphin sightings were all made in NWL, while none was sighted in NEL.

5.3.5 Moreover, both dolphin groups were sighted on primary lines during on-effort search (Annex II of Appendix H). Notably, none of the dolphin groups was associated with any operating fishing vessel.

5.3.6 Distribution of the two dolphin sightings made in December 2018 is shown in Figure 6 of Appendix H. They were sighted to the west of Lung Kwu Chau and near Lung Kwu Tan respectively (Figure 6 of Appendix H).

5.3.7 During the December��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: December 3^rd / 5^th	0.0	0.0
NEL	Set 2: December 10^th / 12^th	0.0	0.0
NWL	Set 1: December 3^rd / 5^th	4.0	11.9
NWL	Set 2: December 10^th / 12^th	0.0	0.0

Remark:

1. Dolphin Encounter Rates Deduced from the Two Sets of Surveys (Two Surveys in Each Set) in December 2018 in Northeast Lantau (NEL) and Northwest Lantau (NWL).

Table 5.4 Monthly Average Encounter Rates

	Encounter rate (STG) (no. of on-effort dolphin sightings per 100 km of survey effort)		Encounter rate (ANI) (no. of dolphins from all on-effort sightings per 100 km of survey effort)
	Primary Lines Only	Both Primary and Secondary Lines	Primary Lines Only	Both Primary and Secondary Lines
Northeast Lantau	0.0	0.0	0.0	0.0
Northwest Lantau	1.9	1.4	5.7	4.3

Remark:

1. Monthly Average Dolphin Encounter Rates (Sightings Per 100 km of Survey Effort) from All Four Surveys Conducted in December 2018 on Primary Lines only as well as Both Primary Lines and Secondary Lines in Northeast Lantau (NEL) and Northwest Lantau (NWL).

5.3.8 As there were only two groups of one and five dolphins being sighted respectively, the average dolphin group size in December 2018 was just three individuals per group, which was much lower than the averages in the previous monitoring months (Annex II of Appendix H).

Photo-identification Work

5.3.9 Three known individual dolphins were sighted three times in total during the December��s surveys (Annexes III and V of Appendix H). All three individuals were re-sighted only once during the monthly surveys. Notably, during their re-sightings in December 2018, none of the identified individuals was sighted with any young calf.

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 (December 2018 �V February 2019) and the 3-month baseline monitoring period will be made.

5.4 Reference

5.4.1 Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., and Thomas, L. 2001. Introduction to distance sampling: estimating abundance of biological populations. Oxford University Press, London.

5.4.2 Hung, S. K. 2017. Monitoring of Marine Mammals in Hong Kong waters: final report (2016-17). An unpublished report submitted to the Agriculture, Fisheries and Conservation Department, 162 pp.

5.4.3 Jefferson, T. A. 2000. Population biology of the Indo-Pacific hump-backed dolphin in Hong Kong waters. Wildlife Monographs 144:1-65.

6 Mudflat Monitoring

6.1 Sedimentation Rate Monitoring

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 1 December 2018. 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 (December 2018)
Monitoring Station	Easting (m)	Northing (m)	Surface Level (mPD)	Easting (m)	Northing (m)	Surface Level (mPD)
S1	810291.160	816678.727	0.950	810291.177	816678.732	1.120
S2	810958.272	815831.531	0.864	810958.261	815831.516	0.974
S3	810716.585	815953.308	1.341	810716.572	815953.312	1.476
S4	811221.433	816151.381	0.931	811221.425	816151.415	1.121

Table 6.3 Comparison of measurement

	Comparison of measurement			Remarks and Recommendation
Monitoring Station	Easting (m)	Northing (m)	Surface Level (mPD)	Remarks and Recommendation
S1	0.017	0.005	0.170	Level continuously increased
S2	-0.011	-0.015	0.110	Level continuously increased
S3	-0.013	0.004	0.135	Level continuously increased
S4	-0.008	0.034	0.190	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 Water Quality Monitoring

6.2.1 The mudflat monitoring covered water quality monitoring data. Reference was made to the water quality monitoring data of the representative water quality monitoring station (i.e. SR3(N)) as in the EM&A Manual. The water quality monitoring location (SR3(N)) is shown in Figure 2.1.

6.2.2 Impact water quality monitoring in San Tau (monitoring station SR3(N)) was conducted in December 2018. The monitoring parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).

6.2.3 The Impact monitoring results for SR3(N) were extracted and summarised below:

Table 6.4 Impact Water Quality Monitoring Results (Depth Average)

Date	Mid Ebb Tide			Mid Flood Tide
Date	DO (mg/L)	Turbidity (NTU)	SS (mg/L)	DO (mg/L)	Turbidity (NTU)	SS (mg/L)
03-Dec-2018	6.8	4.4	7.1	6.7	11.8	13.2
05-Dec-2018	6.8	4.0	5.9	6.8	11.4	15.3
07-Dec-2018	6.7	3.4	6.4	6.9	2.3	6.4
10-Dec-2018	7.2	3.6	5.7	6.6	5.2	11.0
12-Dec-2018	7.1	5.5	9.1	7.5	7.3	12.3
14-Dec-2018	6.7	2.6	5.0	7.4	5.7	10.4
17-Dec-2018	7.6	2.1	3.0	7.2	2.4	4.2
19-Dec-2018	7.4	3.4	4.4	7.2	3.9	7.0
21-Dec-2018	7.1	2.6	5.8	6.7	4.2	7.4
24-Dec-2018	7.2	4.8	8.6	7.3	3.6	6.4
26-Dec-2018	6.7	5.7	7.5	6.9	3.7	7.5
28-Dec-2018	6.8	5.4	7.5	7.1	7.5	8.6
31-Dec-2018	7.7	2.7	5.2	7.6	6.1	8.8
Average	7.1	3.8	6.2	7.1	5.8	9.1

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 December 2018 (totally 5 sampling days between 1^st and 16^thDecember 2018).

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 government agency 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 1^st (for TC3), 2^nd (for TC1), 11^th (for ST) and 15^th (for TC2) December 2018. The weather was warm and sunny on first two survey days (1^st and 2^nd Dec.) while it was cold and cloudy on the following days (11^th and 15^th Dec).

6.3.4 In Jun. 2017, a big horseshoe crab was tangled by a trash gill net in ST mudflat (Figure 2.3 of Appendix I). It was released to sea once after photo recording. The horseshoe crab of such size should be inhabiting sub-tidal environment while it forages on intertidal shore occasionally during high tide period. If it is tangled by the trash net for few days, it may die due to starvation or overheat during low tide period. These trash gill nets are definitely ��fatal trap�� for the horseshoe crabs and other marine life. Manual clean-up should be implemented as soon as possible by responsible government agency units.

Seagrass Beds

6.3.5 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 1^st (for TC3), 2^nd (for TC1), 11^th (for ST) and 15^th (for TC2) December 2018. The weather was warm and sunny on first two survey days (1^st and 2^nd Dec.) while it was cold and cloudy on the following days (11^th and 15^th Dec.).

Intertidal Soft Shore Communities

6.3.6 The intertidal soft shore community surveys were conducted in low tide period on 1^st (for TC3), 2^nd (for TC1), 15^th (for TC2) and 16^th (for ST) December 2018. In every sampling zone, three 100 m 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), AFCD (2018).

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 i^th species.

6.4 Event and Action Plan for Mudflat Monitoring

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

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

6.5 Mudflat Ecology Monitoring Results and Conclusion

Horseshoe Crabs

6.5.1 In the present survey, two species of horseshoe crab (total 15 ind.) and Tachypleus tridentatus (total 13 ind.) were recorded. The recorded individuals were mainly distributed along the shoreline from TC3 to ST. Grouping of 2-3 individuals was usually observed on similar substratum (fine sand or soft mud, slightly submerged).Photo records were shown in Figure 3.1 of Appendix I while the complete survey records were listed in Annex II of Appendix I.

6.5.2 Table 3.1 of Appendix I summarizes the survey results of horseshoe crab in the present survey. In general, very low search record was found for both species in TC1, TC3 and ST. No individual of either species was found in TC2.

6.5.3 For Carcinoscorpius rotundicauda, more individuals (10 ind.) were found in TC3 with average body size 36.34 mm (19.25-71.23 mm). In TC1, there were 4 individuals with average body size 38.39 mm (prosomal width ranged 23.24-58.44 mm). In ST, there was only 1 individual with body size 61.20 mm. The three zones were very low in search record (0.2-1.7 ind. hr^-1 person^-1).

6.5.4 There was similar pattern of survey results for Tachypleus tridentatus. Relatively more individuals were found in TC3 (7 ind.) with average body size 34.90 mm (26.30-38.73 mm). In TC1 and ST, there were only 3 individuals with average body size 47.06-49.13 mm (prosomal width ranged 37.37-66.72 mm). The search record was very low (0.5-1.2 ind. hr^-1 person^-1) for the three zones.

6.5.5 Based on previous monitoring results, there were similar searach records of horseshoe crab in TC3 and ST. But it was relatively higher in TC3 in present survey because the survey was conducted under warmer weather in early December. The survey for ST was conducted in mid December while the ambient temperature dropped significantly. It could decrease the activity rate of horseshoe crab.

6.5.6 In the 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). It indicated the importance of ST as a breeding ground of horseshoe crab. In Jun. 2017, mating pairs of Carcinoscorpius rotundicauda were also found in TC2 (male 175.27 mm, female 143.51 mm) and TC3 (male 182.08 mm, female 145.63 mm) (Figure 3.2 of Appendix I). In Dec. 2017 and Jun. 2018 , one mating pair was of Carcinoscorpius rotundicauda was found in TC3 (Dec. 2017: male 127.80 mm, female 144.61 mm; Jun. 2018: male 139 mm, female 149 mm). Figure 3.2 of Appendix I shows the photographic records of all mating pairs found. The recorded mating pairs were found nearly burrowing in soft mud at low tidal level (0.5-1.0 m above C.D.). The smaller male was holding the opisthosoma (abdomen carapace) of larger female from behind. These mating pairs indicated that breeding of horseshoe crab could be possible along the coast of Tung Chung Wan rather than ST only, as long as suitable substratum was available. Based on the frequency of encounter, the shoreline between TC3 and ST should be more suitable mating ground. Moreover suitable breeding period was believed in wet season (Mar - Sep.) because tiny individuals (i.e. newly hatched) were usually recorded in Jun. and Sep. every year.

6.5.7 Despite of mating pair, there were occasional records of large individuals of Carcinoscorpius rotundicauda (prosomal width ranged 114.45 - 178.67 mm, either single or in pair) and Tachypleus tridentatus (prosomal width 103 mm) (Figure 3.3 of Appendix I). In the present survey (Dec. 2018), one large individual of Carcinoscorpius rotundicauda was found in TC3 (prosomal width 148.94 mm). Based on their sizes, it indicated that individuals of prosomal width larger than 100 mm would progress its nursery stage from intertidal habitat to sub-tidal habitat of Tung Chung Wan. These large individuals might move onto intertidal shore occasionally during high tide for foraging and breeding. Because they should be inhabiting sub-tidal habitat most of the time. Their records were excluded from the data analysis to avoid mixing up with juvenile population living on intertidal habitat.

6.5.8 No marked individual of horseshoe crab was recorded in the present survey. Some marked individuals were found in the previous surveys of Sep. 2013, Mar. 2014 and Sep. 2014. All of them were released through a conservation programme in charged by Prof. Paul Shin (Department of Biology and Chemistry, The City University of Hong Kong (CityU)). It was a re-introduction trial of artificial bred horseshoe crab juvenile at selected sites. So that the horseshoe crab population might be restored in the natural habitat. Through a personal conversation with Prof. Shin, about 100 individuals were released in the sampling zone ST on 20 June 2013. All of them were marked with color tape and internal chip detected by specific chip sensor. There should be second round of release between June and September 2014 since new marked individuals were found in the survey of Sep. 2014.

6.5.9 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

6.5.10 Figures 3.5 and 3.6 of Appendix I show the changes of number of individuals, mean prosomal width and search record of horseshoe crabs Carcinoscorpius rotundicauda and Tachypleus tridentatus respectively in every sampling zone throughout the monitoring period.

6.5.11 For TC3 and ST, medium to high search records (i.e. number of individuals) of both species were always found in wet season (Jun. and Sep.). The search record of ST was higher from Sep. 2012 to Jun. 2014 while it was replaced by TC3 from Sep. 2014 to Jun. 2015. The search records were similar between two sampling zones from Sep. 2015 to Jun. 2016. In Sep. 2016, the search record of Carcinoscorpius rotundicauda in ST was much higher than TC3. From Mar. to Jun. 2017, the search records of both species were similar again between two sampling zones. It showed a natural variation of horseshoe crab population in these two zones due to weather condition and tidal effect. No obvious difference of horseshoe crab population was noted between TC3 and ST. In Sep. 2017, the search records of both horseshoe crab species decreased except the Carcinoscorpius rotundicauda in TC3. The survey results were different from previous findings that there were usually higher search records in September. One possible reason was that the serial cyclone hit decreased horseshoe crab activity (totally 4 cyclone records between Jun. and Sep. 2017, to be discussed in 'Seagrass survey' section). From Dec. 2017 to Sep. 2018, the search records of both species increased again to low-moderate level in ST. Relatively higher population fluctuation of Tachypleus tridentatus was observed in TC3.

6.5.12 For TC1, the search record was at low to moderate level throughout the monitoring period. The change of Carcinoscorpius rotundicauda was relatively more variable than that of Tachypleus tridentatus. Relatively, the search record was very low in TC2. There were occasional records of 1 to 4 individuals between March and September throughout the monitoring period. The maximum record was 6 individuals only in Jun. 2016.

6.5.13 About the body size, larger individuals of Carcinoscorpius rotundicauda were usually found in ST and TC1 relative to those in TC3 from Sep. 2012 to Jun. 2017. But the body size was higher in TC3 and ST followed by TC1 from Sep. 2017 to Jun. 2018. In Sep. 2018, larger individuals were found in ST and TC1 again. For Tachypleus tridentatus, larger individuals were usually found in ST and TC3 followed by TC1 throughout the monitoring period.

6.5.14 In general, it was obvious that the shoreline along TC3 and ST (western shore of Tung Chung Wan) was an important nursery ground for horseshoe crab especially newly hatched individuals due to larger area of suitable substratum (fine sand or soft mud) and less human disturbance (far from urban district). Relatively, other sampling zones were not a suitable nursery ground especially TC2. Possible factors were less area of suitable substratum (especially TC1) and higher human disturbance (TC1 and TC2: close to urban district and easily accessible). In TC2, large daily salinity fluctuation was a possible factor either since it was flushed by two rivers under tidal inundation. The individuals inhabiting TC1 and TC2 were confined in small foraging area due to limited area of suitable substratum. Although a mating pair of Carcinoscorpius rotundicauda was once found in TC2, the hatching rate and survival rate of newly hatched individuals were believed very low.

Seasonal variation of horseshoe crab population

6.5.15 Throughout the monitoring period, the search record of horseshoe crab declined obviously during dry season especially December (Figures 3.4 and 3.5 of Appendix I). Very low �V low search record was found in December from 2012 to 2015 (0-4 ind. of Carcinoscorpius rotundicauda and 0-12 ind. of Tachypleus tridentatus). The horseshoe crabs were inactive and burrowed in the sediments during cold weather (<15 ºC). Similar results of low search record in dry season were reported in a previous territory-wide survey of horseshoe crab. For example, the search records in Tung Chung Wan were 0.17 ind. hr^-1 person^-1 and 0.00 ind. hr^-1 person^-1 in wet season and dry season respectively (details see Li, 2008). Relatively the search records were much higher in Dec. 2016. There were totally 70 individuals of Carcinoscorpius rotundicauda and 24 individuals of Tachypleus tridentatus in TC3 and ST. Because the survey was arranged in early December while the weather was warm with sunlight (~22 �XC during dawn according to Hong Kong Observatory database, Chek Lap Kok station on 5 Dec.). In contrast, there was no search record in TC1 and TC2 because the survey was conducted in mid December with colder and cloudy weather (~20 �XC during dawn on 19 Dec.). The horseshoe crab activity would decrease gradually with the colder climate. In December of 2017 and 2018 (present survey), very low search records were found again as mentioned above.

6.5.16 From Sep. 2012 to Dec. 2013, Carcinoscorpius rotundicauda was a less common species relative to Tachypleus tridentatus. Only 4 individuals were ever recorded in ST in Dec. 2012. This species had ever been believed of very low density in ST hence the encounter rate was very low. In Mar. 2014, it was found in all sampling zones with higher abundance in ST. Based on its average size (mean prosomal width 39.28-49.81 mm), it indicated that breeding and spawning of this species had occurred about 3 years ago along the coastline of Tung 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).

6.5.17 For Tachypleus tridentatus, sharp increase of number of individuals was recorded in ST during the wet season of 2013 (from Mar. to Sep.). According to a personal conversation with Prof. Shin (CityU), his monitoring team had recorded similar increase of horseshoe crab population during wet season. It was believed that the suitable ambient temperature increased its conspicuousness. However similar pattern was not recorded in the following wet seasons. The number of individuals increased in Mar. and Jun. 2014 followed by a rapid decline in Sep. 2014. Then the number of individuals fluctuated slightly in TC3 and ST until Mar. 2017. Apart from natural mortality, migration from nursery soft shore to subtidal habitat was another possible cause. Since the mean prosomal width of Tachypleus tridentatus continued to grow and reached about 50 mm since Mar. 2014. Then it varied slightly between 35-65 mm from Sep. 2014 to Mar. 2017. Most of the individuals might have reached a suitable size (e.g. prosomal width 50-60 mm) strong enough to forage in sub-tidal habitat. In Jun. 2017, the number of individuals increased sharply again in TC3 and ST. Although mating pair of Tachypleus tridentatus was not found in previous surveys, there should be new round of spawning in the wet season of 2016. The individuals might have grown to a more conspicuous size in 2017 accounting for higher search record. In Sep. 2017, moderate numbers of individual were found in TC3 and ST indicating a stable population size. In Sep. 2018, the population size was lower while natural mortality was the possible cause.

6.5.18 Recently, Carcinoscorpius rotundicauda was a more common horseshoe crab species in Tung Chung Wan. It was recorded in the four sampling zones while the majority of population located in TC3 and ST. Due to potential breeding last year, Tachypleus tridentatus became common again and distributed in TC3 and ST mainly. Since TC3 and ST were regarded as important nursery ground for both horseshoe crab species, box plots of prosomal width of two horseshoe crab species were constructed to investigate the changes of population in details.

Box plot of horseshoe crab populations in TC3

6.5.19 Figure 3.7 of Appendix I shows the changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking. In Mar 2014, the major size (50% of individual records between upper (top of red box) and lower quartile (bottom of blue box)) ranged 40-60 mm while only few individuals were found. From Mar. 2014 to Sep. 2018, the median prosomal width (middle line of whole box) and major size (whole box) decreased after Mar. of every year. It was due to more small individuals found in June indicating new rounds of spawning. Also, there were slight increasing trends of body size from Jun. to Mar. of next year since 2015. It indicated a stable growth of individuals. Focused on larger juveniles (upper whisker), the size range was quite variable (prosomal width 60-90 mm) along the sampling months. Juveniles reaching this size might gradually migrate to sub-tidal habitats.

6.5.20 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, similar increasing trend of major size was noted with much higher number of individuals. It reflected new round of spawning. In Sep. 2017, the major size decreased while the trend was different from previous two years. Such decline might be the cause of serial cyclone hit between Jun. and Sep. 2017 (to be discussed in the 'Seagrass survey' section). From Dec. 2017 to Sep. 2018, increasing trend was noted again. Across the whole monitoring period, the larger juveniles (upper whisker) usually reached 60-80 mm in prosomal width, even 90 mm occasionally. Juveniles reaching this size might gradually migrate to sub-tidal habitats.

Box plot of horseshoe crab populations in ST

6.5.21 Figure 3.8 of Appendix I shows the changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius rotundicauda was rarely found between Sep. 2012 and Dec. 2013 hence the data were lacking. From Mar. 2014 to Sep. 2018, the size of major population decreased and more small individuals (i.e. lower whisker) were recorded after Jun. of every year. It indicated new round of spawning. Also there were similar increasing trends of body size from Sep. to Jun. of next year between 2014 and 2017. It indicated a stable growth of individuals. Across the whole monitoring period, the larger juveniles (i.e. upper whisker) usually ranged 60-80 mm in prosomal width except one individual (prosomal width 107.04 mm) found in Mar. 2017. It reflected juveniles reaching this size would gradually migrate to sub-tidal habitats.

6.5.22 For Tachypleus tridentatusa, a consistent growing trend was observed for the major population from Dec. 2012 to Dec. 2014 regardless of change of search record. The prosomal width increased from 15-30 mm to 60-70 mm. As mentioned, the large juveniles might have reached a suitable size for migrating from the nursery soft shore to subtidal habitat. From Mar. to Sep. 2015, the size of major population decreased slightly to a prosomal width 40-60 mm. At the same time, the number of individuals decreased gradually. It further indicated some of large juveniles might have migrated to sub-tidal habitat, leaving the smaller individuals on shore. There was an overall growth trend. In Dec. 2015, two big individuals (prosomal width 89.27 mm and 98.89 mm) were recorded only while it could not represent the major population. In Mar. 2016, the number of individual was very few in ST that no boxplot could be produced. In Jun. 2016, the prosomal width of major population ranged 50-70 mm. But it dropped clearly to 30-40 mm in Sep. 2016 followed by an increase to 40-50 mm in Dec. 2016, 40-70 mm in Mar. 2017 and 50-60mm in Jun. 2017. Based on overall higher number of small individuals from Jun. 2016 to Sep. 2017, it indicated another round of spawning. From Sep. 2017 to Jun. 2018, the major size range increased slightly from 40-50 mm to 45-60 mm indicating a continous growth. In Sep. 2018, decrease of major size was noted again that might reflect new round of spawning. Throughout the monitoring period, the larger juveniles ranged 60-80 mm in prosomal width. Juveniles reaching this size would gradually migrate to sub-tidal habitats.

6.5.23 As a summary for horseshoe crab populations in TC3 and ST, there were spawning of Carcinoscorpius rotundicauda from 2014 to 2018 while the spawning time should be in spring. The population size was consistent in these two sampling zones. For Tachypleus tridentatus, small individuals were rarely found in both zones from 2014 to 2015. It was believed no occurrence of successful spawning. The existing individuals (that recorded since 2012) grew to a mature size and migrated to sub-tidal habitat. Hence the number of individuals decreased gradually. From 2016 to 2018, new rounds of spawning were recorded in ST while the population size increased to a moderate level.

Impact of the HKLR project

6.5.24 It was the 25^th survey of the EM&A programme during the construction period. Based on the monitoring results, impact of the HKLR project was not detected on horseshoe crabs. The population change was mainly determined by seasonal variation while new rounds of spawning were observed for both species. Abnormal phenomenon (e.g. very few numbers of horseshoe crab individuals in wet season, large number of dead individuals on the shore) had not been reported.

Seagrass Beds

6.5.25 Since the commencement of the EM&A monitoring programme, two species of seagrass Halophila ovalis and Zostera japonica were recorded in TC3 and ST (Figure 3.9 of Appendix I). In general Halophila ovalis was occasionally found in TC3 in few, small to medium patches. But it was commonly found in ST in medium to large seagrass bed. Moreover it had sometimes grown extensively and had covered significant mudflat area at 0.5-2.0 m above C.D. between TC3 and ST. Another seagrass species Zostera japonica was found in ST only. It was relatively lower in vegetation area and was co-existing with Halophila ovalis nearby the mangrove strand at 2.0 m above C.D..

6.5.26 Table 3.2 of Appendix I summarizes the results of present seagrass beds survey. Seagrass beds were found in ST only. There were two low-medium sized, horizontal strands of Halophila ovalis with total seagrass bed area ~ 404 m² (Figure 3.10 of Appendix I). The larger strand had area ~264 m² in medium-high vegetation coverage 50-85%, located at tidal zone 1.5-2.0 m above C.D nearby mangrove plantation. At close vicinity, there was a smaller horizontal strand (~140 m², low coverage 5-20%). Another seagrass species Zostera japonica was not found in present survey. Annex III of Appendix I shows the complete record of seagrass survey.

6.5.27 According to the previous results, majority of seagrass bed was confined in ST, the temporal change of both seagrass species were investigated in details:

Temporal variation of seagrass beds

6.5.28 Figure 3.11 of Appendix I shows the changes of estimated total area of seagrass beds in ST along the sampling months. For Zostera japonica, it was not recorded in the 1^st and 2^nd surveys of monitoring programme. Seasonal recruitment of few, small patches (total seagrass area: 10 m²) was found in Mar. 2013 that grew within the large patch of seagrass Halophila ovalis. Then the patch size increased and merged gradually with the warmer climate from Mar. to Jun. 2013 (15 m²). However the patch size decreased and remained similar from Sep. 2013 (4 m²) to Mar. 2014 (3 m²). In Jun. 2014, the patch size increased obviously again (41 m²) with warmer climate followed by a decrease between Sep. 2014 (2 m²) and Dec. 2014 (5 m²). From Mar. to Jun. 2015, the patch size increased sharply again (90 m²). It might be due to the disappearance of the originally dominant seagrass Halophila ovalis resulting in less competition for substratum and nutrients. From Sep. 2015 to Jun. 2016, it was found coexisting with seagrass Halophila ovalis with steady increasing patch size (from 44 m² to 115 m²) and variable coverage. In Sep. 2016, the patch size decreased again to (38 m²) followed by an increase to a horizontal strand (105.4 m²) in Jun. 2017. And it was no longer co-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. However such increasing trend was not found from Sep. 2017 to Dec. 2018 (present survey) while no patch of Zostera japonica was found.

6.5.29 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 large patch at low tidal level (786 m²). Typhoon or strong water current was a possible cause (Fong, 1998). In Sep. 2014, there were two tropical cyclone records in Hong Kong (7^th-8^th Sep.: no cyclone name, maximum signal number 1; 14^th-17^th Sep.: Kalmaegi, maximum signal number 8SE) before the seagrass survey dated 21^st 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.

6.5.30 In Dec. 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.12 of Appendix I shows the difference of the original seagrass beds area nearby the mangrove vegetation at high tidal level between Jun. 2014 and Dec. 2014. Such rapid loss would not be seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m above C.D.) were present and normal in December 2012 and 2013. According to Fong (1998), similar incident had occurred in ST in the past. The original seagrass area had declined significantly during the commencement of the construction and reclamation works for the international airport at Chek Lap Kok in 1992. The seagrass almost disappeared in 1995 and recovered gradually after the completion of reclamation works. Moreover, incident of rapid loss of seagrass area was also recorded in another intertidal mudflat in Lai Chi Wo in 1998 with unknown reason. Hence Halophila ovalis was regarded as a short-lived and r-strategy seagrass that could colonize areas in short period but disappears quickly under unfavourable conditions (Fong, 1998).

Unfavourable conditions to seagrass Halophila ovalis

6.5.31 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.

6.5.32 Prolonged light deprivation due to turbid water would be another unfavouable condition. Previous studies reported that Halophila ovalis had little tolerance to light deprivation. During experimental darkness, seagrass biomass declined rapidly after 3-6 days and seagrass died completely after 30 days. The rapid death might be due to shortage of available carbohydrate under limited photosynthesis or accumulation of phytotoxic end products of anaerobic respiration (details see Longstaff et al., 1999). Hence the seagrass bed of this species was susceptible to temporary light deprivation events such as flooding river runoff (Longstaff and Dennison, 1999).

6.5.33 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 10^th 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 1^st to 10^th 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.

6.5.34 Based on the weather condition and water quality results in ST, the co-occurrence of cyclone hit and turbid waters in Sep. 2014 might have combined the adverse effects on Halophila ovalis that leaded to disappearance of this short-lived and r-strategy seagrass species. Fortunately, Halophila ovalis was a fast-growing species (Vermaat et al., 1995). Previous studies showed that the seagrass bed could be recovered to the original sizes in 2 months through vegetative propagation after experimental clearance (Supanwanid, 1996). Moreover, it was reported to recover rapidly in less than 20 days after dugong herbivory (Nakaoka and Aioi, 1999). As mentioned, the disappeared seagrass in ST in 1995 could recover gradually after the completion of reclamation works for international airport (Fong, 1998). The seagrass beds of Halophila ovalis might recolonize the mudflat of ST through seed reproduction as long as there was no unfavourable condition in the coming months.

Recolonization of seagrass beds

6.5.35 Figure 3.12 of Appendix I shows the recolonization of seagrass bed area in ST from Dec. 2014 to Jun. 2017. From Mar. to Jun. 2015, 2-3 small patches of Halophila ovalis were newly found co-inhabiting 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-selected 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. The total seagrass bed decreased to 12550 m². From Mar. to Jun. 2017, the seagrass bed area remained generally stable (12438-17046.5 m²) but the vegetation coverage fluctuated (20-50% in Mar. 2017 to 80-100% in Jun. 2017). The whole recolonization process took about 2.5 years.

Re-disappearance of seagrass bed

6.5.36 In Sep 2017, the whole seagrass bed of Halophila ovalis disappeared again along the shore of TC3 and ST (Figure 3.12 of Appendix I). It was similar to the case between Sep. and Dec. 2014. As mentioned, strong water current (e.g. cyclone) or deteriorated water quality (e.g. high turbidity) were the possible causes.

6.5.37 Between the survey periods of Jun. and Sep. 2017, there were four tropical cyclone records in Hong Kong (Merbok in 12-13^th, Jun.; Roke in 23^rd, Jul.; Hato in 22-23^rd, Aug.; Pakhar in 26-27^th, Aug.) (online database of Hong Kong Observatory). All of them reaches signal 8 or above especially Hato (highest signal 10).

6.5.38 According to the water quality monitoring results (Jul. to Aug. 2017) of the two closest monitoring stations SR3 and I5 of the respective EM&A programme, the overall water quality was in normal fluctuation. There was one exceedance of suspended solids (SS) at SR3 on 12 Jul. 2017. The SS concentration reached 24.7 mg/L during mid-ebb tide. It exceeded the Action Level (≤23.5 mg/L) but was far below the Limit Level (≤34.4 mg/L). Since such exceedance was slight and temporary, its effect to seagrass bed should be minimal.

6.5.39 Overall, the disappearance of seagrass beds in ST was believed the cause of serial cyclone hit in Jul and Aug. 2017. Based on previous findings, the seagrass beds of both species were expected to recolonize the mudflat as long as the vicinal water quality was normal. The whole recolonization process (from few, small patches to extensive strand) would be gradual lasting minimum 2 years. From Dec. 2017 to Mar. 2018, there was still no recolonization of few, small patches of seagrass at the usual location (Fig. 3.12). It was different from previous round (Mar. 2015 - Jun. 2017). Until Jun. 2018, new, small-medium seagrass patches were found at the usual location (seaward side of mangrove plantation at 2.0 m C.D.) again, indicating the recolonization. However the seagrass bed area decreased sharply to 22.5 m² in Sep. 2018. Again it was believed the hit of super cyclone in Sep. 2018 (Mangkhut on 16^th Sep., highest signal 10). In Dec. 2018 (present survey), the seagrass bed area increased again. Relatively, it would occour later and slower than previous round (more than 2 years).

Impact of the HKLR project

It was the 25^th survey of the EM&A programme during the construction period. Throughout the monitoring period, the disappearance of seagrass beds was believed the cause of cyclone hits rather than impact of HKLR project. There was slow and gradual recolonization in the following dry season.

Intertidal Soft Shore Communities

6.5.40 Table 3.3 and Figure 3.13 of Appendix I show the substratum types along the horizontal transct at every tidal level in all sampling zones. The relative distribution of substratum types was estimated by categorizing the substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random quadrats along the horizontal transect. The distribution of substratum types varied among tidal levels and sampling zones:

�P In TC1, high percentages of ��Gravels and Boulders�� (80-90%) were recorded at high and mid tidal levels. Relatively higher percentages of ��Gravels and Boulders�� (40%) and ��Soft mud�� (40%) were recorded at low tidal level.

�P In TC2, higher percentage of ��Sands�� (60%) was recorded at high tidal level. At mid tidal level, there was higher percentage of ��Soft mud�� (60%) followed by ��Gravels and Boulders�� (40%). At low tidal level, the major substratum type was 'Soft mud' (80%).

�P In TC3, higher percentage of ��Sands�� (70%) was recorded followed by ��Soft mud�� (30%) at high tidal level. At mid tidal level, higher percentages of ��Soft mud�� (60%) and ��Sands�� (40%) were recorded. At low tideal level, the main substratum type was ��Gravels and Boulders�� (90%).

�P In ST, ��Gravels and Boulders�� was the main substratum type (100%) at high tidal level. At mid tidal level, there were even distribution of ��Gravels and Boulders�� (50%) and ��Sands�� (50%). At low tidal level, ��Sands�� was the main substratum type (80%).

6.5.41 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.

6.5.42 Table 3.4 of Appendix I lists the total abundance, density and number of taxon of every phylum in this survey. A total of 14429 individuals were recorded. Mollusca was clearly the most abundant phylum (total abundance 14217 ind., density 474 ind. m^-2, relative abundance 98.5 %). The second and third abundant phya were Arthropoda (114 ind., 4 ind. m^-2, 0.8 %) and Annelida (70 ind., 2 ind. m^-2, 0.5 %) respectively. Relatively other phyla were very low in abundances (density £1 ind. m^-2, relative abundance £0.1 %). Moreover, the most diverse phylum was Mollusca (33 taxa) followed by Arthropoda (10 taxa) and Annelida (9 taxa). There was 1-2 taxa recorded only for other phyla.

6.5.43 The taxonomic resolution and complete list of recorded fauna are shown in Annexes IV and V of Appendix I respectively. As reported in Jun. 2018, taxonomic revision of three potamidid snail species was conducted according to the latest identification key published by Agriculture, Fisheries and Conservation Department (details see AFCD, 2018), the species names of following gastropod species were revised:

�P Cerithidea cingulata was revised as Pirenella asiatica

�P Cerithidea djadjariensis was revised as Pirenella incisa

�P Cerithidea rhizophorarum was revised as Cerithidea moerchii

Morover, taxonomic revision was conducted on another snail species while the specie name was revised.:

�P Batillaria bornii was revised as Clypeomorus bifasciata

6.5.44 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 (2195-4738 ind.) varied among the four sampling zones while the phyla distributions were similar. In general, Mollusca was the most dominant phylum (no. of individuals: 2152-4690 ind.; relative abundance 97.9-99.1 %; density 287-625 ind. m^-2). Other phyla were much lower in number of individuals. Arthropoda (16-49 ind.; 0.6-1.1 %; 2-7 ind. m^-2) and Annelida (2-36 ind.; 0.1-0.9 %; 0-5 ind. m^-2) were common phyla relatively. Other phyla were very low in abundance in all sampling zones.

Dominant species in every sampling zone

6.5.45 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.

6.5.46 In TC1, the substratum was mainly ��Gravels and Boulders�� at high and mid tidal levels. The high tidal level was clearly dominated by gastropod Batillaria multiformis (514 ind. m^-2, relative abundance 68 %) at very high density followed by gastropod Pirenella incisa (98 ind. m^-2, 13 %). At mid tidal level, gastropod Batillaria multiformis (184 ind. m^-2, 33 %) and Monodonta labio (156 ind. m^-2, 28 %) were abundant at moderate densities. Rock oyster Saccostrea cucullata (86 ind. m^-2, 16 %, attached on boulders) was also abundant at low-moderate density. At low tidal level (main substratum types ��Gravels and Boulders�� or ��Soft mud��), rock oyster Saccostrea cucullata (207 ind. m^-2, 35 %) was more abundant at moderate density. Other gastropods Pirenella incisa (103 ind. m^-2, 17 %), Batillaria zonalis (75 ind. m^-2, 13 %) and Lunella coronata (61 ind. m^-2, 10 %) were found at low-moderate densities.

6.5.47 In TC2, the substratum types were mainly 'Sands' at high tidal level. Gastropods Pirenella incisa (100 ind. m^-2, 28 %), Pirenella asiatica (63 ind. m^-2, 17 %) and rock oyster Saccostrea cucullata (68 ind., 19 %, attached on boulders) were abundant at low-moderate densities. Other gastropods Batillaria zonalis (45 ind. m^-2, 13 %) and Batillaria multiformis (40 ind. m^-2, 11 %) were also common. At mid tidal level (main substratum type ��Soft mud��), rock oyster Saccostrea cucullata (124 ind. m^-2, 36 %) was abundant at moderate density followed by gastropods Pirenella incisa (63 ind. m^-2, 18 %) and Batillaria zonalis (49 ind. m^-2, 14 %). At low tidal level (main substratum type ��Soft mud��), gastropod Batillaria zonalis (70 ind. m^-2, 41 %) was abundant at low-moderate desnity followed by common rocky oyster Saccostrea cucullata (31 ind. m^-2, 18 %) and gastropod Pirenella asiatica (19 ind. m^-2, 11 %).

6.5.48 In TC3, the substratum types were either ��Sands�� or ��Soft mud�� at high and mid tidal levels. Gastropod Pirenella incisa (233-365 ind. m^-2, 47-64 %) was dominant followed by gastropods Pirenella asiatica (67-126 ind. m^-2, 12-25 %) and Batillaria multiformis (80-82 ind. m^-2, 14-16 %) at low-moderate densities. At low tidal level (major substratum: ��Gravels and Boulders��), rock oyster Saccostrea cucullata (266 ind. m^-2, 38 %, attached on boulders) and gastropod Monodonta labio (220 ind. m^-2, 31 %) were abundant at moderate densities, followed by gastropod Lunella coronata (77 ind. m^-2, 11 %).

6.5.49 In ST, the major substratum type was ��Gravels and Boulders�� at high tidal level. There were few abundant gastropod species at low-moderate densities including Batillaria multiformis (123 ind. m^-2, 26 %), Monodonta labio (97 ind. m^-2, 20 %), Lunella coronata (52 ind. m^-2, 11 %) and Clypeomorus bifasciata (50 ind. m^-2, 10 %). At mid and low tidal levels (main substratum types ��Gravels and Boulders�� and 'Sands'), rock oyster Saccostrea cucullata (52-143 ind. m^-2, 22-28 %, attached on boulders) was more abundant at low-moderate densities. Other abundant gastropods Pirenella incisa (44-82 ind. m^-2, 16-19 %), Monodonta labio (36-77 ind. m^-2, 15-16 %) and Lunella coronata (25-76 ind. m^-2, 11-15 %) were at low-moderate densities. Besides, gastropod Pirenella asiatica (74 ind. m^-2, 14 %) was also abundant at mid tidal level.

6.5.50 In general, there was no consistent zonation pattern of species distribution across all sampling zones and tidal levels. The species distribution was determined by the type of substratum primarily. In general, gastropods Pirenella incisa (total number of individuals: 2921 ind., relative abundance 20.2 %), Batillaria multiformis (2628 ind., 18.2 %), Pirenella asiatica (1421 ind., 9.8 %) and Batillaria zonalis (769 ind., 5.3 %) were the most commonly occurring species on sandy and soft mud substrata. Rock oyster Saccostrea cucullata (2635 ind., 18.3 %), gastropods Monodonta labio (1806 ind., 12.5 %) and Lunella coronata (881 ind., 6.1 %) were the commonly occurring species inhabiting gravel and boulders substratum.

Biodiversity and abundance of soft shore communities

6.5.51 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.

6.5.52 Among the sampling zones, the mean species number was similar (6-9 spp. 0.25 m^-2) among the four sampling zones. The mean densities of TC1 and TC3 (591-632 ind. m^-2) were higher than ST (409 ind. m^-2) followed by TC2 (293 ind. m^-2). Overall, ST was relatively higher in H' (1.6) and J (0.8) due to higher species number and even taxa distribution. In TC1 and TC3, higher densities were mainly accounted by 1-2 abundant gastropods. It resulted in lower H�� (1.2-1.3) and J (0.6-0.7). In TC2, lower species number and density also resulted in lower H' (1.3) and J (0.7).

6.5.53 Among the tidal levels, there were slightly increasing trends of mean species number, H' and J from high to low tidal level in TC1 and TC3 but vice versa in TC2 and ST. A general decreasing trend of mean density was observed from high to low tidal level in TC1, TC2 and ST. As mentioned, the spatial differences of these biological parameters were highly related to substratum types.

6.5.54 Figures 3.14 to 3.17 of Appendix I show the temporal changes of mean species number, mean density, H�� and J at every tidal level and in every sampling zone along the sampling months. In general, all the biological parameters fluctuated seasonally throughout the monitoring period. Lower mean species number and density were recorded in dry season (Dec.) but the mean H' and J fluctuated within a limited range.

6.5.55 From Jun. to Dec. 2017, there were steady decreasing trends of mean species number and density in TC2, TC3 and ST regardless of tidal levels. It might be an unfavourable change reflecting environmental stresses. The heat stress and serial cyclone hit were believed the causes during the wet season of 2017. From Mar. to Oct. 2018, increases of mean species number and density were observed in all sampling zones. It indicated the recovery of intertidal community.

Impact of the HKLR project

6.5.56 It was the 25^th survey of the EM&A programme during the construction period. Based on the results, impacts of the HKLR project were not detected on intertidal soft shore community. Abnormal phenomena (e.g. rapid, consistent or non-seasonal decline of fauna densities and species number) were not recorded.

6.6 Reference

6.6.1 AFCD, 2018. Potamidid Snails in Hong Kong Mangrove. Agriculture, Fisheries and Conservation Department Newsletter - Hong Kong Biodiversity Issue #25, 2-11

6.6.2 Chan, K.K., Caley, K.J., 2003. Sandy Shores, Hong Kong Field Guides 4. The Department of Ecology & Biodiversity, The University of Hong Kong. pp 117.

6.6.3 Dai, A.Y., Yang, S.L., 1991. Crabs of the China Seas. China Ocean Press. Beijing.

6.6.4 Dong, Y.M., 1991. Fauna of ZheJiang Crustacea. Zhejiang Science and Technology Publishing House. ZheJiang.

6.6.5 EPD, 1997. Technical Memorandum on Environmental Impact Assessment Process (1st edition). Environmental Protection Department, HKSAR Government.

6.6.6 Fauchald, K., 1977. The polychaete worms. Definitions and keys to the orders, families and genera. Natural History Museum of Los Angeles County, Science Series 28. Los Angeles, U.S.A..

6.6.7 Fong, C.W., 1998. Distribution of Hong Kong seagrasses. In: Porcupine! No. 18. The School of Biological Sciences, The University of Hong Kong, in collaboration with Kadoorie Farm & Botanic Garden Fauna Conservation Department, p10-12.

6.6.8 Li, H.Y., 2008. The Conservation of Horseshoe Crabs in Hong Kong. MPhil Thesis, City University of Hong Kong, pp 277.

6.6.9 Longstaff, B.J., Dennison, W.C., 1999. Seagrass survival during pulsed turbidity events: the effects of light deprivation on the seagrasses Halodule pinifolia and Halophila ovalis. Aquatic Botany 65 (1-4), 105-121.

6.6.10 Longstaff, B.J., Loneragan, N.R., 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.

6.6.11 Nakaoka, M., Aioi, K., 1999. Growth of seagrass Halophila ovalis at dugong trails compared to existing within-patch variation in a Thailand intertidal flat. Marine Ecology Progress Series 184, 97-103.

6.6.12 Pielou, E.C., 1966. Shannon��s formula as a measure of species diversity: its use and misuse. American Naturalist 100, 463-465.

6.6.13 Qi, Z.Y., 2004. Seashells of China. China Ocean Press. Beijing, China.

6.6.14 Qin, H., Chiu, H., Morton, B., 1998. Nursery beaches for Horseshoe Crabs in Hong Kong. In: Porcupine! No. 18. The School of Biological Sciences, The University of Hong Kong, in collaboration with Kadoorie Farm & Botanic Garden Fauna Conservation Department, p9-10.

6.6.15 Shannon, C.E., Weaver, W., 1963. The Mathematical Theory of Communication. Urbana: University of Illinois Press, USA.

6.6.16 Shin, P.K.S., Li, H.Y., Cheung, S.G., 2009. Horseshoe Crabs in Hong Kong: Current Population Status and Human Exploitation. Biology and Conservation of Horseshoe Crabs (part 2), 347-360.

6.6.17 Supanwanid, C., 1996. Recovery of the seagrass Halophila ovalis after grazing by dugong. In: Kuo, J., Philips, R.C., Walker, D.I., Kirkman, H. (eds), Seagrass biology: Proc Int workshop, Rottenest Island, Western Australia. Faculty of Science, The University of Western Australia, Nedlands, 315-318.

6.6.18 Vermaat, J.E., Agawin, N.S.R., Duarte, C.M., Fortes, M.D., Marba. N., Uri, J.S., 1995. Meadow maintenance, growth and productivity of a mixed Philippine seagrass bed. Marine Ecology Progress Series 124, 215-225.

6.6.19 Yang, D.J, Sun, R.P., 1988. Polychaetous annelids commonly seen from the Chinese waters (Chinese version). China Agriculture Press, China

7 Environmental Site Inspection and Audit

7.1 Site Inspection

7.1.1 Site Inspections were carried out on a weekly basis to monitor the implementation of proper environmental pollution control and mitigation measures for the Project. During the reporting month, four site inspections were carried out on 5, 12, 19, and 28 December 2018.

7.1.2 A summary of observations found during the site inspections and the follow up actions taken by the Contractor are described in Table 7.1.

Table 7.1 Summary of Environmental Site Inspections

Date of Audit	Observations	Actions Taken by Contractor / Recommendation	Date of Observations Closed
30 Nov 2018	1. Stagnant water was observed at N4. 2. Waste was observed at N4 3. Dry stockpile was observed at N4. 4. Waste was observed at LCSD.	1. The stagnant water was removed from N4. 2. The waste was removed from N4. 3. The dry stockpile was removed from N4. 4. The waste was removed from LCSD.	5 Dec 2018
5 Dec 2018	1. Waste was observed at LCSD Depot. 2. Waste was accumulated in a skip at N4.	1. The waste was removed from LCSD Depot. 2. The waste was removed from the skip at N4.	12 Dec 2018
12 Dec 218	1. Waste was observed at LCSD Depot. 2. Stagnant water was observed at N4.	1. The waste was removed from LCSD Depot. 2. The stagnant water was removed at N4.	19 Dec 2018
19 Dec 2018	1. Waste was observed at LCSD Depot. 2. Stockpile of dusty material was observed dry at N4. 3. Waste was accumulated in a skip at N4.	1. The waste was removed from LCSD Depot. 2. The dry stockpile of dusty material was removed from N4. 3. The waste was removed from the skip at N4.	28 Dec 2018
28 Dec 2018	1. Waste was observed at LCSD Depot. 2. Waste was observed at N4 . 3. Containers of liquid chemicals were observed without drip trays underneath at N4. 4. Stockpiles of material were placed around a Tree at N4. 5. Wheel washing facilities were missing at N4.	The Contractor was recommended to: 1. remove the waste at LCSD Depot 2. remove the waste at N4. 3. provide drip trays for the chemical containers at N4. 4. remove the stockpiles of material near the tree at N4. 5. provide wheel washing facilities at N4.	Follow-up actions for the observations issued for the last weekly site inspection of the reporting month will be inspected during the next site inspection.

7.1.3 The Contractor has rectified most of the observations as identified during environmental site inspections within the reporting month. Follow-up actions for outstanding observations will be inspected during the next site inspection.

7.2 Advice on the Solid and Liquid Waste Management Status

7.2.1 The Contractor registered as a chemical waste producer for the Contract. Sufficient numbers of receptacles were available for general refuse collection and sorting.

7.2.2 Monthly summary of waste flow table is detailed in Appendix J.

7.2.3 The Contractor was reminded that chemical waste containers should be properly treated and stored temporarily in designated chemical waste storage area on site in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.

7.3 Environmental Licenses and Permits

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 Summary of Exceedances of the Environmental Quality Performance Limit

7.5.1 For air quality, 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.

7.5.3 For marine water quality monitoring, no Action Level and Limit Level exceedances of dissolved oxygen level and turbidity level were recorded during the reporting month. During the reporting month, two Action Level exceedance of suspended solids level was recorded. No Limit Level exceedances of suspended solids level were recorded.

7.6 Summary of Complaints, Notification of Summons and Successful Prosecution

7.6.1 There was one complaint received in relation to the environmental impacts during the reporting month. Complaint investigation is being undertaken and will be reported in next reporting month. A summary of environmental complaint during the reporting month is presented in Table 7.2.

Table 7.2 A Summary of Environmental Complaint during the Reporting Month

Environmental Complaint No.	Date of Complaint Received	Description of Environmental Complaint
Complaint No COM-2018-158	SOR referred the email from HyD to Contractor, ET and IEC/ENPO on 24 December 2018	Other: Construction work on Sunday Morning

7.6.2 The details of cumulative statistics of Environmental Complaints are provided in Appendix K.

7.6.3 No notification of summons and prosecution was received during the reporting period. Statistics on notifications of summons and successful prosecutions are summarized in Appendix N.

8 Future Key Issues

8.1 Construction Programme for the Coming Months

8.1.1 As informed by the Contractor, the major construction activities for January 2019 are summarized in Table 7.1.

Table 7.1 Construction Activities for January 2019

Site Area	Description of Activities
Portion X	Dismantling/ trimming of Temporary 40mm Stone Platform for Construction of Seawall
Portion X	Construction of Seawall
Portion X	Loading and Unloading of Filling Materials
Portion X	Backfilling at Scenic Hill Tunnel (Cut & Cover Tunnel)
Airport Road	Works for Diversion of Airport Road
Airport Road / Airport Express Line/ East Coast Road	Establishment of Site Access
Portion X	Finishing works for Highway Operation and Maintenance Area Building
West Portal	Finishing Works for Scenic Hill Tunnel West Portal Ventilation Building

8.2 Environmental Monitoring Schedule for the Coming Month

8.1.2 The tentative schedule for environmental monitoring in January 2019 is provided in Appendix D.

9 Conclusions

9.1 Conclusions

9.1.1 The construction phase and EM&A programme of the Contract commenced on 17 October 2012. This is the seventy-fifth Monthly EM&A report for the Contract which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 to 31 December 2018.

Air Quality

9.1.2 For air quality, No Action Level and Limit Level exceedance 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 level and turbidity level were recorded during the reporting month. During the reporting month, two Action Level exceedance of suspended solids level was recorded. No Limit Level exceedances of suspended solids level were recorded.

Dolphin

9.1.5 During the December��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 (December 2018 �V February 2019) 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 December 2018 survey results indicate that the impacts of the HKLR project could not be detected on horseshoe crabs and intertidal soft shore community. Throughout the monitoring period, the disappearance of seagrass beds was believed the cause of cyclone hits rather than impact of HKLR project. There was slow and gradual recolonization of seagrass in the following dry season.

Environmental Site Inspection and Audit

9.1.9 Environmental site inspections were carried out on 5, 12, 19, and 28 December 2018. Recommendations on remedial actions were given to the Contractors for the deficiencies identified during the site inspections.

9.1.10 There was one complaint received in relation to the environmental impact during the reporting period. Complaint investigation is being undertaken and will be reported in next reporting month.

1.1.4 The Contract includes the following key aspects:

1.1.5 This is the seventy-fifth Monthly EM&A report for the Contract which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 to 31 December 2018.

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.

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.

2 Air Quality Monitoring

2.1 Monitoring Requirements

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.

2.4.1 Table 2.5 summarizes the monitoring parameters, frequency and duration of impact TSP monitoring.

2.5.1 24-hour TSP Monitoring

2.5.2 1-hour TSP Monitoring

2.6.1 The schedule for air quality monitoring in December 2018 is provided in Appendix D.

2.7 Monitoring Results

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.

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.

3.2 Monitoring Equipment

3.3 Monitoring Locations

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.

3.4.1 Table 3.4 summarizes the monitoring parameters, frequency and duration of impact noise monitoring.

3.5.1 Monitoring Procedure

3.5.2 Maintenance and Calibration

3.6.1 The schedule for construction noise monitoring in December 2018 is provided in Appendix D.

3.7 Monitoring Results

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.

*A correction factor of +3dB(A) from free field to facade measurement was included.

3.7.2 There were no Action and Limit Level exceedances for noise during daytime on normal weekdays of the reporting month.

3.7.3 The event action plan is annexed in Appendix F.

4 Water Quality Monitoring

4.1.2 The original and revised Action Level and Limit Level for turbidity and suspended solid are shown in Table 4.1.

4.2.1 Table 4.2 summarizes the equipment used in the impact water quality monitoring programme.

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.

4.4.4 The locations of water quality monitoring stations during the reporting period are summarized in Table 4.4 and shown in Figure 2.1.

4.5 Monitoring Methodology

4.5.1 Instrumentation

4.5.2 Operating/Analytical Procedures

4.5.3 Maintenance and Calibrations

(a) All in situ monitoring instruments would be calibrated by ALS Technichem (HK) Pty Ltd. before use and at 3-monthly intervals throughout all stages of the water quality monitoring programme. The procedures of performance check of sonde and testing results are provided in Appendix C.

4.6.1 The schedule for impact water quality monitoring in December 2018 is provided in Appendix D.

4.7 Monitoring Results

4.7.1 Impact water quality monitoring was conducted at all designated monitoring stations during the reporting month. Impact water quality monitoring results and relevant graphical plots are provided in Appendix E.

4.7.2 Water quality impact sources during water quality monitoring were the construction activities of the Contract, nearby construction activities by other parties and nearby operating vessels by other parties.

4.7.3 For marine water quality monitoring, no Action Level and Limit Level exceedances of dissolved oxygen level and turbidity level were recorded during the reporting month.

4.7.4 During the reporting month, two Action Level exceedances of suspended solids level were recorded. No Limit Level exceedances of suspended solids level were recorded.

4.7.5 Number of exceedances recorded during the reporting month at each impact station are summarized in Table 4.6.

Table 4.6 Summary of Water Quality Exceedances

4.7.7 The event action plan is annexed in Appendix F.

5.1 Monitoring Requirements

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.

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

5.2.5 Data including time, position and vessel speed were also automatically and continuously logged by handheld GPS throughout the entire survey for subsequent review.

Photo-identification Work

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).

Vessel-based Line-transect Survey

5.3.1 During the month of December 2018, two sets of systematic line-transect vessel surveys were conducted on the 3rd, 5th, 10th and 12th 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 261.96 km of survey effort was collected, with 90.3% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility) (Annex I of Appendix H).

5.3.3 Among the two survey areas, 97.00 km and 164.96 km of survey effort were collected from NEL and NWL survey areas respectively. Moreover, the total survey effort conducted on primary lines was 193.46 km, while the effort on secondary lines was 68.50 km.

5.3.4 During the two sets of monitoring surveys in December 2018, two groups of six Chinese White Dolphins were sighted (see Annex II of Appendix H). Both dolphin sightings were all made in NWL, while none was sighted in NEL.

5.3.5 Moreover, both dolphin groups were sighted on primary lines during on-effort search (Annex II of Appendix H). Notably, none of the dolphin groups was associated with any operating fishing vessel.

5.3.6 Distribution of the two dolphin sightings made in December 2018 is shown in Figure 6 of Appendix H. They were sighted to the west of Lung Kwu Chau and near Lung Kwu Tan respectively (Figure 6 of Appendix H).

5.3.7 During the December��s surveys, encounter rates of Chinese White Dolphins deduced from the survey effort and on-effort sighting data made under favourable conditions (Beaufort 3 or below) are shown in Tables 5.3 and 5.4.

5.3.8 As there were only two groups of one and five dolphins being sighted respectively, the average dolphin group size in December 2018 was just three individuals per group, which was much lower than the averages in the previous monitoring months (Annex II of Appendix H).

Photo-identification Work

Conclusion

5.3.10 During this month of dolphin monitoring, no adverse impact from the activities of this construction project on Chinese White Dolphins was noticeable from general observations.

5.4 Reference

5.4.1 Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., and Thomas, L. 2001. Introduction to distance sampling: estimating abundance of biological populations. Oxford University Press, London.

5.4.2 Hung, S. K. 2017. Monitoring of Marine Mammals in Hong Kong waters: final report (2016-17). An unpublished report submitted to the Agriculture, Fisheries and Conservation Department, 162 pp.

5.4.3 Jefferson, T. A. 2000. Population biology of the Indo-Pacific hump-backed dolphin in Hong Kong waters. Wildlife Monographs 144:1-65.

Methodology

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.

5.3.1 During the month of December 2018, two sets of systematic line-transect vessel surveys were conducted on the 3^rd, 5^th, 10^th and 12^th 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.