Environmental Complaint No.	Date of Complaint Received	Description of Environmental Complaints
COM-2015-079	7 December 2015	Water Quality

2 EM&A Requirement

2.1 Summary of EM&A Requirements

2.1.1 The EM&A programme requires environmental monitoring of air quality, noise, water quality, dolphin monitoring and mudflat monitoring as specified in the approved EM&A Manual.

2.1.2 A summary of Impact EM&A requirements is presented in Table 2.1. The locations of air quality, noise and water quality monitoring stations are shown as in Figure 2.1. The transect line layout in Northwest and Northeast Lantau Survey Areas is presented in Figure 2.2.

Table 2.1 Summary of Impact EM&A Requirements

Environmental Monitoring	Description	Monitoring Station	Frequencies	Remarks
Air Quality	1-hr TSP	AMS 5 & AMS 6	At least 3 times every 6 days	While the highest dust impact was expected.
Air Quality	24-hr TSP	AMS 5 & AMS 6	At least once every 6 days	--
Noise	L_eq_(30mins)_, L₁₀_(30mins)and L₉₀_(30mins)	NMS5	At least once per week	Daytime on normal weekdays (0700-1900 hrs).
Water Quality	· Depth · Temperature · Salinity · Dissolved Oxygen (DO) · Suspended Solids (SS) · DO Saturation · Turbidity · pH	· 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	Three times per week during mid-ebb and mid-flood tides (within ± 1.75 hour of the predicted time)	3 (1 m below water surface, mid-depth and 1 m above sea bed, except where the water depth is less than 6 m, in which case the mid-depth station may be omitted. Should the water depth be less than 3 m, only the mid-depth station will be monitored).
Dolphin	Line-transect Methods	Northeast Lantau survey area and Northwest Lantau survey area	Twice per month	--
Mudflat	Horseshoe crabs, seagrass beds, intertidal soft shore communities, sedimentation rates and water quality	San Tau and Tung Chung Bay	Once every 3 months	--

2.2 Action and Limit Levels

2.2.1 Table 2.2 presents the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.

Table 2.2 Action and Limit Levels for 1-hour TSP, 24-hour TSP and Noise

Environmental Monitoring	Parameters	Monitoring Station	Action Level	Limit Level
Air Quality	1-hr TSP	AMS 5	352 µg/m³	500 µg/m³
	1-hr TSP	AMS 6	360 µg/m³	500 µg/m³
	24-hr TSP	AMS 5	164 µg/m³	260 µg/m³
	24-hr TSP	AMS 6	173 µg/m³	260 µg/m³
Noise	L_{eq (30 min)}	NMS 5	When one documented complaint is received	75 dB(A)

2.2.2 The Action and Limit Levels for water quality monitoring are given as in Table 2.3.

Table 2.3 Action and Limit Levels for Water Quality

Parameter (unit)	Water Depth	Action Level	Limit Level
Dissolved Oxygen (mg/L)	Surface and Middle	5.0	4.2 except 5 for Fish Culture Zone
Dissolved Oxygen (mg/L)	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. Therefore, the amended Action and Limit Levels are applied for the water monitoring results obtained on and after 25 March 2013.

2.2.3 The Action and Limit Levels for dolphin monitoring are shown in Tables 2.4 and 2.5.

Table 2.4 Action and Limit Level for Dolphin Impact Monitoring

	North Lantau Social Cluster
	NEL	NWL
Action Level	STG < 70% of baseline & ANI < 70% of baseline	STG < 70% of baseline & ANI < 70% of baseline
Limit Level	STG < 40% of baseline & ANI < 40% of baseline

Remarks:

(1) STG means quarterly average encounter rate of number of dolphin sightings.

(2) ANI means quarterly average encounter rate of total number of dolphins.

(3) For North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall below the criteria; LL will be triggered if both NEL and NWL fall below the criteria.

Table 2.5 Derived Value of Action Level (AL) and Limit Level (LL)

	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 average encounter rate of number of dolphin sightings.

(2) ANI means quarterly average encounter rate of total number of dolphins.

(3) For North Lantau Social Cluster, AL will be triggered if either NEL or NWL fall below the criteria; LL will be triggered if both NEL and NWL fall below the criteria.

2.3 Event Action Plans

2.3.1 The Event Actions Plans for air quality, noise, water quality and dolphin monitoring are annexed in Appendix D.

2.4 Mitigation Measures

2.4.1 Environmental mitigation measures for the contract were recommended in the approved EIA Report. Appendix E lists the recommended mitigation measures and the implementation status.

3 Environmental Monitoring and Audit

3.1 Implementation of Environmental Measures

3.1.1 In response to the site audit findings, the Contractor have rectified all observations identified in environmental site inspections undertaken during the reporting period. Details of site audit findings and the corrective actions during the reporting period are presented in Appendix F.

3.1.2 A summary of the Implementation Schedule of Environmental Mitigation Measures (EMIS) is presented in Appendix E.

3.1.3 Regular marine travel route for marine vessels were implemented properly in accordance to the submitted plan and relevant records were kept properly.

3.1.4 Dolphin Watching Plan was implemented during the reporting period. No dolphins inside the silt curtain were observed. The relevant records were kept properly.

3.2 Air Quality Monitoring Results

3.2.1 The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2 respectively. Detailed impact air quality monitoring results and relevant graphical plots are presented in Appendix G.

Table 3.1 Summary of 1-hour TSP Monitoring Results Obtained During the Reporting Period

Reporting Period	Monitoring Station	Average (mg/m³)	Range (mg/m³)	Action Level (mg/m³)	Limit Level (mg/m³)
September 2015	AMS5	95	58 - 151	352	500
September 2015	AMS6	97	66 - 138	360
October 2015	AMS5	123	87 - 204	352
October 2015	AMS6	105	73 - 255	360
November 2015	AMS5	125	65 - 312	352
November 2015	AMS6	127	78 - 316	360

Table 3.2 Summary of 24-hour TSP Monitoring Results Obtained During the Reporting Period

Reporting Period	Monitoring Station	Average (mg/m³)	Range (mg/m³)	Action Level (mg/m³)	Limit Level (mg/m³)
September 2015	AMS5	36	18 - 77	164	260
September 2015	AMS6	61	34 - 119	173
October 2015	AMS5	51	14 - 92	164
October 2015	AMS6	80	27 - 136	173
November 2015	AMS5	55	37 - 71	164
November 2015	AMS6	71	42 - 93	173

3.2.2 There were no Action and Limit Level exceedances of 1-hour TSP and 24-hour TSP were recorded at AMS5 and AMS6 during the reporting period.

3.3 Noise Monitoring Results

3.3.1 The monitoring results for construction noise are summarized in Table 3.3 and the monitoring results and relevant graphical plots for this reporting period are provided in Appendix H.

Table 3.3 Summary of Construction Noise Monitoring Results Obtained During the Reporting Period

Reporting period	Monitoring Station	Average L_{eq (30 mins)}, dB(A)*	Range of L_{eq (30 mins)}, dB(A)*	Action Level	Limit Level L_{eq (30 mins)}, dB(A)
September 2015	NMS5	56	55 – 58	When one documented complaint is received	75
October 2015		58	58 – 59
November 2015		60	58 – 67

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

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

3.3.3 Major noise sources during the noise monitoring included construction activities of the Contract and nearby traffic noise and insect noise.

3.4 Water Quality Monitoring Results

3.4.1 Impact water quality monitoring was conducted at all designated monitoring stations during the reporting period. Impact water quality monitoring results and relevant graphical plots are provided in Appendix I.

3.4.2 During the reporting period, ten Action Level exceedances for suspended solid level were recorded. Record of “Notification of Environmental Quality Limit Exceedances” is provided in Appendix M. No exceedance of Limit Level for suspended solid level was recorded. No exceedances of Action and Limit Level for dissolved oxygen level and turbidity were recorded.

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

3.5 Dolphin Monitoring Results

Data Analysis

3.5.1 Distribution Analysis – The line-transect survey data was integrated with the Geographic Information System (GIS) in order to visualize and interpret different spatial and temporal patterns of dolphin distribution using sighting positions. Location data of dolphin groups were plotted on map layers of Hong Kong using a desktop GIS (ArcView© 3.1) to examine their distribution patterns in details. The dataset was also stratified into different subsets to examine distribution patterns of dolphin groups with different categories of group sizes, young calves and activities.

3.5.2 Encounter rate analysis – Encounter rates of Chinese White Dolphins (number of on-effort sightings per 100 km of survey effort, and total number of dolphins sighted on-effort 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. Dolphin encounter rates were calculated in two ways for comparisons with the HZMB baseline monitoring results as well as to AFCD long-term marine mammal monitoring results.

3.5.3 Firstly, for the comparison with the HZMB baseline monitoring results, the encounter rates were calculated using primary survey effort alone, and only data collected under Beaufort 3 or below condition would be used for encounter rate analysis. The average encounter rate of sightings (STG) and average encounter rate of dolphins (ANI) were deduced based on the encounter rates from six events during the present quarter (i.e. six sets of line-transect surveys in North Lantau), which was also compared with the one deduced from the six events during the baseline period (i.e. six sets of line-transect surveys in North Lantau).

3.5.4 Secondly, the encounter rates were calculated using both primary and secondary survey effort collected under Beaufort 3 or below condition as in AFCD long-term monitoring study. The encounter rate of sightings and dolphins were deduced by dividing the total number of on-effort sightings and total number of dolphins (ANI) by the amount of survey effort for the present quarterly period.

3.5.5 Quantitative grid analysis on habitat use – To conduct quantitative grid analysis of habitat use, positions of on-effort sightings of Chinese White Dolphins collected during the quarterly impact phase monitoring period were plotted onto 1-km² grids among Northwest Lantau (NWL) and Northeast (NEL) survey areas on GIS. Sighting densities (number of on-effort sightings per km²) and dolphin densities (total number of dolphins from on-effort sightings per km²) were then calculated for each 1 km by 1 km grid with the aid of GIS. Sighting density grids and dolphin density grids were then further normalized with the amount of survey effort conducted within each grid. The total amount of survey effort spent on each grid was calculated by examining the survey coverage on each line-transect survey to determine how many times the grid was surveyed during the study period. For example, when the survey boat traversed through a specific grid 50 times, 50 units of survey effort were counted for that grid. With the amount of survey effort calculated for each grid, the sighting density and dolphin density of each grid were then normalized (i.e. divided by the unit of survey effort).

3.5.6 The newly-derived unit for sighting density was termed SPSE, representing the number of on-effort sightings per 100 units of survey effort. In addition, the derived unit for actual dolphin density was termed DPSE, representing the number of dolphins per 100 units of survey effort. Among the 1-km² grids that were partially covered by land, the percentage of sea area was calculated using GIS tools, and their SPSE and DPSE values were adjusted accordingly. The following formulae were used to estimate SPSE and DPSE in each 1-km² grid within the study area:

SPSE = ((S / E) x 100) / SA%

DPSE = ((D / E) x 100) / SA%

where S = total number of on-effort sightings

D = total number of dolphins from on-effort sightings

E = total number of units of survey effort

SA% = percentage of sea area

3.5.7 Behavioural analysis – When dolphins were sighted during vessel surveys, their behaviour was observed. Different activities were categorized (i.e. feeding, milling/resting, traveling, socializing) and recorded on sighting datasheets. This data was then input into a separate database with sighting information, which can be used to determine the distribution of behavioural data with a desktop GIS. Distribution of sightings of dolphins engaged in different activities and behaviours would then be plotted on GIS and carefully examined to identify important areas for different activities of the dolphins.

3.5.8 Ranging pattern analysis – Location data of individual dolphins that occurred during the 3-month baseline monitoring period were obtained from the dolphin sighting database and photo-identification catalogue. To deduce home ranges for individual dolphins using the fixed kernel methods, the program Animal Movement Analyst Extension, was loaded as an extension with ArcView© 3.1 along with another extension Spatial Analyst 2.0. Using the fixed kernel method, the program calculated kernel density estimates based on all sighting positions, and provided an active interface to display kernel density plots. The kernel estimator then calculated and displayed the overall ranging area at 95% UD level.

Summary of Survey Effort and Dolphin Sightings

3.5.9 During the period of September to November 2015, six sets of systematic line-transect vessel surveys were conducted to cover all transect lines in NWL and NEL survey areas twice per month.

3.5.10 From these surveys, a total of 902.25 km of survey effort was collected, with 95.0% of the total survey effort being conducted under favourable weather conditions (i.e. Beaufort Sea State 3 or below with good visibility). Among the two areas, 346.64 km and 555.61 km of survey effort were conducted in NEL and NWL survey areas respectively.

3.5.11 The total survey effort conducted on primary lines 656.41 km, while the effort on secondary lines was 245.84 km. Survey effort conducted on both primary and secondary lines were considered as on-effort survey data. A summary table of the survey effort is shown in Annex I of Appendix J.

3.5.12 During the six sets of monitoring surveys in September-November 2015, a total of 18 groups of 95 Chinese White Dolphins were sighted. A summary table of the dolphin sightings is shown in Annex II of Appendix J.

3.5.13 For the present quarterly period, all dolphin sightings were made during on-effort search, and all except one dolphin sighting were made on primary lines. Moreover, all dolphin groups were sighted in NWL, while none was sighted at all in NEL. In fact, since July 2014, only one sighting of a lone dolphin was made in NEL during HKLR03 monitoring surveys.

Distribution

3.5.14 Distribution of dolphin sightings made during monitoring surveys in September to November 2015 is shown in Figure 1 of Appendix J. Dolphin sightings made in the present quarter were mostly clustered around Lung Kwu Chau (Figure 1 of Appendix J). A few other sightings were also made near Sha Chau and to the west of the airport platform (Figure 1 of Appendix J).

3.5.15 Notably, all dolphin sightings were made far away from the HKLR03/HKBCF reclamation sites as well as along the entire alignment of Tuen Mun-Chek Lap Kok Link (TMCLKL) during the present quarterly period (Figure 1 of Appendix J). On the other hand, two sightings with five dolphins were made in the vicinity of the HKLR09 alignment (Figure 1 of Appendix J).

3.5.16 Sighting distribution of the present impact phase monitoring period (September to November 2015) was compared to the one during the baseline monitoring period (September to November 2011). In the present quarter, dolphins have disappeared from the NEL region, which was in stark contrast to their frequent occurrence around the Brothers Islands, near Shum Shui Kok and in the vicinity of HKBCF reclamation site during the baseline period (Figure 1 of Appendix J). The nearly complete abandonment of NEL region by the dolphins has been consistently recorded in the past eleven quarters of HKLR03 monitoring, which has resulted in zero to extremely low dolphin encounter rate in this area.

3.5.17 In NWL survey area, dolphin occurrence was also drastically different between the baseline and impact phase periods. During the present impact monitoring period, fewer dolphins occurred in this survey area than during the baseline period, when many of the dolphin sightings were concentrated between Lung Kwu Chau and Black Point, around Sha Chau, near Pillar Point and to the west of the Chek Lap Kok Airport (Figure 1 of Appendix J).

3.5.18 Another comparison in dolphin distribution was made between the three quarterly periods of autumn months in 2013, 2014 and 2015 (Figure 2 of Appendix J). Among the three autumn periods, no dolphin was sighted at all in NEL in both 2014 and 2015, while two sightings were made there in 2013 (Figure 2 of Appendix J).

3.5.19 On the other hand, dramatic changes in dolphin distribution in NWL waters were also observed in the autunm months during the three-year period (Figure 2 of Appendix J). In 2013, dolphins regularly occurred throughout the NWL survey area, with higher concentrations of sightings around Sha Chau, Lung Kwu Chau, near Black Point and Pillar Point. In 2014, dolphins still frequently occurred around Sha Chau and Lung Kwu Chau, but less frequently in the middle portion of the North Lantau region. In 2015, they infrequently occurred in NWL survey area with the only concentration of sightings around Lung Kwu Chau, while they generally absent for the rest of this area. Similar temporal changes in dolphin distribution were also observed in the spring and summer periods of 2013-15. The temporal trend indicated that dolphin usage in the NWL region has progressively diminished in recent years.

Encounter Rate

3.5.20 During the present three-month study period, the encounter rates of Chinese White Dolphins deduced from the survey effort and on-effort sighting data from the primary transect lines under favourable conditions (Beaufort 3 or below) for each set of the surveys in NEL and NWL are shown in Table 3.4. The average encounter rates deduced from the six sets of surveys were also compared with the ones deduced from the baseline monitoring period (September – November 2011) (See Table 3.5).

Table 3.4 Dolphin Encounter Rates (Sightings Per 100 km of Survey Effort) During Reporting Period (September to November 2015)

Survey Area	Dolphin Monitoring	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)
Survey Area	Dolphin Monitoring	Primary Lines Only	Primary Lines Only
Northeast Lantau	Set 1 (2 & 11 Sep 2015)	0.00	0.00
	Set 2 (17 & 29 Sep 2015)	0.00	0.00
	Set 3 (6 & 13 Oct 2015)	0.00	0.00
	Set 4 (19 & 26 Oct 2015)	0.00	0.00
	Set 5 (2 & 6 Nov 2015)	0.00	0.00
	Set 6 (10 & 16 Nov 2015)	0.00	0.00
Northwest Lantau	Set 1 (2 & 11 Sep 2015)	5.47	51.95
	Set 2 (17 & 29 Sep 2015)	4.01	21.38
	Set 3 (6 & 13 Oct 2015)	5.86	24.91
	Set 4 (19 & 26 Oct 2015)	2.73	10.94
	Set 5 (2 & 6 Nov 2015)	3.84	15.38
	Set 6 (10 & 16 Nov 2015)	1.73	1.73

Table 3.5 Comparison of average dolphin encounter rates from impact monitoring period (September to November 2015) and baseline monitoring period (September – November 2011)

Survey Area	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)
Survey Area	Reporting Period	Baseline Monitoring Period	Reporting Period	Baseline Monitoring Period
Northeast Lantau	0.0	6.00 ± 5.05	0.0	22.19 ± 26.81
Northwest Lantau	3.94 ± 1.57	9.85 ± 5.85	21.05 ± 17.19	44.66 ± 29.85

Notes:
1) The encounter rates deduced from the baseline monitoring period have been recalculated based only on the survey effort and on-effort sighting data made along the primary transect lines under favourable conditions.

2) ± denotes the standard deviation of the average encounter rates.

3.5.21 To facilitate the comparison with the AFCD long-term monitoring results, the encounter rates were also calculated for the present quarter using both primary and secondary survey effort. The encounter rates of sightings (STG) and dolphins (ANI) in NWL were 3.31 sightings and 17.52 dolphins per 100 km of survey effort respectively, while the encounter rates of sightings (STG) and dolphins (ANI) in NEL were both nil for this quarter.

3.5.22 In NEL, the average dolphin encounter rates (both STG and ANI) in the present three-month impact monitoring period were zero with no sighting made, and such low occurrence of dolphins in NEL have been consistently recorded in the past eleven quarters of HKLR03 monitoring (Table 3.6). This is a serious concern as the dolphin occurrence in NEL in the last eleven quarters (0.0-1.0 for ER(STG) and 0.0-3.9 for ER(ANI)) have been exceptionally low when compared to the baseline period (Table 3.6). Dolphins have almost vacated from NEL waters since January 2014, with only two groups of five dolphins sighted there since then despite consistent and intensive survey effort being conducted in this survey area.

Table 3.6 Comparison of Average Dolphin Encounter Rates in Northeast Lantau Survey Area from All Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep – Nov 2011)

Monitoring Period	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)
September-November 2011 (Baseline)	6.00 ± 5.05	22.19 ± 26.81
December 2012-February 2013 (Impact)	3.14 ± 3.21	6.33 ± 8.64
March-May 2013 (Impact)	0.42 ± 1.03	0.42 ± 1.03
June-August 2013 (Impact)	0.88 ± 1.36	3.91 ± 8.36
September-November 2013 (Impact)	1.01 ± 1.59	3.77 ± 6.49
December 2013-February 2014 (Impact)	0.45 ± 1.10	1.34 ± 3.29
March-May 2014 (Impact)	0.00	0.00
June-August 2014 (Impact)	0.42 ± 1.04	1.69 ± 4.15
September-November 2014 (Impact)	0.00	0.00
December 2014-February 2015 (Impact)	0.00	0.00
March-May 2015 (Impact)	0.00	0.00
June – August 2015 (Impact)	0.44 ± 1.08	0.44 ± 1.08
September-November 2015 (Impact)	0.00	0.00

Notes:
1) The encounter rates deduced from the baseline monitoring period have been recalculated based only on survey effort and on-effort sighting data made along the primary transect lines under favourable conditions.

2) ± denotes the standard deviation of the average encounter rates.

3.5.23 Moreover, the average dolphin encounter rates (STG and ANI) in NWL during the present impact phase monitoring period were also much lower (reductions of 60.0% and 52.9% respectively) than the ones recorded in the 3-month baseline period, indicating a dramatic decline in dolphin usage of this survey area as well during the present impact phase period (Table 3.7).

3.5.24 Even for the same autumn quarters, the dolphin encounter rates in NWL during autumn 2015 were much lower than the ones recorded in autumn 2013 and 2014 (Table 3.7).

3.5.25 It should be noted that the encounter rates in NWL in the present quarter have slightly rebounded from the exceptionally low level in the previous three quarters (Table 3.7). Such potential rebound in dolphin occurrence could be an encouraging sign, and should be continuously monitored in the upcoming monitoring quarters.

Table 3.7 Comparison of Average Dolphin Encounter Rates in Northwest Lantau Survey Area from All Quarters of Impact Monitoring Period and Baseline Monitoring Period (Sep – Nov 2011)

Monitoring Period	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)
September-November 2011 (Baseline)	9.85 ± 5.85	44.66 ± 29.85
December 2012-February 2013 (Impact)	8.36 ± 5.03	35.90 ± 23.10
March-May 2013 (Impact)	7.75 ± 3.96	24.23 ± 18.05
June-August 2013 (Impact)	6.56 ± 3.68	27.00 ± 18.71
September-November 2013 (Impact)	8.04 ± 1.10	32.48 ± 26.51
December 2013-February 2014 (Impact)	8.21 ± 2.21	32.58 ± 11.21
March-May 2014 (Impact)	6.51 ± 3.34	19.14 ± 7.19
June-August 2014 (Impact)	4.74 ± 3.84	17.52 ± 15.12
September-November 2014 (Impact)	5.10 ± 4.40	20.52 ± 15.10
December 2014-February 2015 (Impact)	2.91 ± 2.69	11.27 ± 15.19
March-May 2015 (Impact)	0.47 ± 0.73	2.36 ± 4.07
June – August 2015 (Impact)	2.53 ± 3.20	9.21 ± 11.57
September-November 2015 (Impact)	3.94 ± 1.57	21.05 ± 17.19

Notes:

1) The encounter rates deduced from the baseline monitoring period have been recalculated based only on survey effort and on-effort sighting data made along the primary transect lines under favourable conditions.

2) ± denotes the standard deviation of the average encounter rates.

3.5.26 As discussed recently in Hung (2015), the dramatic decline in dolphin usage of NEL waters in the past few years (including the declines in abundance, encounter rate and habitat use in NEL, as well as shifts of individual core areas and ranges away from NEL waters) was possibly related to the HZMB construction works that were commenced since 2012. It appeared that such noticeable decline has already extended to NWL waters progressively in 2013 to 2015.

3.5.27 A two-way ANOVA with repeated measures and unequal sample size was conducted to examine whether there were any significant differences in the average encounter rates between the baseline and impact monitoring periods. The two variables that were examined included the two periods (baseline and impact phases) and two locations (NEL and NWL).

3.5.28 For the comparison between the baseline period and the present quarter (twelfth quarter of the impact phase being assessed), the p-values for the differences in average dolphin encounter rates of STG and ANI were 0.0079 and 0.071 respectively. If the alpha value is set at 0.05, significant differences were detected between the baseline and present quarters in the dolphin encounter rate of STG, but not in the dolphin encounter rate of ANI.

3.5.29 For the comparison between the baseline period and the cumulative quarters in impact phase (i.e first twelve quarters of the impact phase being assessed), the p-values for the differences in average dolphin encounter rates of STG and ANI were 0.00009 and 0.00003 respectively. Even if the alpha value is set at 0.0001, significant differences were still detected in both the average dolphin encounter rates of STG and ANI (i.e. between the two periods and the locations).

3.5.30 As indicated in both dolphin distribution patterns and encounter rates, dolphin usage has been significantly reduced in both NEL and NWL survey areas during the present quarterly period, and such low occurrence of dolphins has also been consistently documented in previous quarters. This raises serious concern, as the timing of the decline in dolphin usage in North Lantau waters coincided well with the construction schedule of the HZMB-related projects (Hung 2015).

3.5.31 To ensure the continuous usage of North Lantau waters by the dolphins, every possible measure should be implemented by the contractors and relevant authorities of HZMB-related works to minimize all disturbances to the dolphins.

Group Size

3.5.32 Group size of Chinese White Dolphins ranged from one to twelve individuals per group in North Lantau region during September to November 2015. The average dolphin group sizes from these three months were compared with the ones deduced from the baseline period in September to November 2011, as shown in Table 3.8.

Table 3.8 Comparison of Average Dolphin Group Sizes between Reporting Period (Sep – Nov 2015) and Baseline Monitoring Period (Sep – Nov 2011)

Survey Area	Average Dolphin Group Size
Survey Area	Reporting Period	Baseline Monitoring Period
Overall	5.28 ± 3.54 (n = 18)	3.72 ± 3.13 (n = 66)
Northeast Lantau	N/A	3.18 ± 2.16 (n = 17)
Northwest Lantau	5.28 ± 3.54 (n = 18)	3.92 ± 3.40 (n = 49)

Note:

1) ± denotes the standard deviation of the average group size.

3.5.33 The average dolphin group sizes in NWL waters during September to November 2015 was higher than the ones recorded during the three-month baseline period (Table 3.8). Seven of the 18 groups were composed of 1-3 individuals only, while five other groups were moderate in size with 4-6 individuals per group. Moreover, six large dolphin groups were sighted during the present quarterly period, including three groups with 7-9 individuals each, and another three groups with 10-12 individuals each.

3.5.34 Distribution of dolphins with larger group sizes (five individuals or more per group and ten individuals per group) during the present quarter is shown in Figure 3 of Appendix J, with comparison to the one in baseline period. During the autumn months of 2015, distribution of these large groups of dolphins were all located around Lung Kwu Chau and Sha Chau, with the three exceptionally large groups of dolphins (i.e. with 10 or more individuals) sighted adjacent to Lung Kwu Chau (Figure 3 of Appendix J). This distribution pattern was very different from the baseline period, when the larger dolphin groups were distributed more evenly in NWL waters with a few more sighted in NEL waters (Figure 3 of Appendix J).

Habitat Use

3.5.35 From September to November 2015, the only area being heavily utilized by Chinese White Dolphins was around and to the north of Lung Kwu Chau, as well as both eastern and western sides of Sha Chau in North Lantau region (Figures 4a and 4b of Appendix J). All grids near HKLR03/HKBCF reclamation sites as well as TMCLKL alignment did not record any presence of dolphins during on-effort search in the present quarterly period, but one grid (F19) in the vicinity of HKLR09 alignment recorded moderately high dolphin densities (Figures 4b of Appendix J).

3.5.36 It should be emphasized that the amount of survey effort collected in each grid during the three-month period was fairly low (6-12 units of survey effort for most grids), and therefore the habitat use pattern derived from the three-month dataset should be treated with caution. A more complete picture of dolphin habitat use pattern should be examined when more survey effort for each grid will be collected throughout the impact phase monitoring programme.

3.5.37 When compared with the habitat use patterns during the baseline period, dolphin usage in NEL and NWL has dramatically diminished in both areas during the present impact monitoring period (Figure 5 of Appendix J). During the baseline period, many grids between Siu Mo To and Shum Shui Kok recorded moderately high to high dolphin densities, which was in stark contrast to the complete absence of dolphins there during the present impact phase period (Figure 5 of Appendix J).

3.5.38 The density patterns were also very different in NWL between the baseline and impact phase monitoring periods, with higher dolphin usage around Sha Chau, near Black Point, to the west of the airport, as well as between Pillar Point and airport platform during the baseline period. In contrast, only the waters around Lung Kwu Chau and Sha Chau recorded high densities of dolphins during the present impact phase period (Figure 5 of Appendix J).

Mother-calf Pairs

3.5.39 During the present quarterly period, two young calves (i.e. unspotted calf or unspotted juvenile) were spotted with their mothers near Lung Kwu Chau

3.5.40 The rare occurrence of young calves in the present quarter was in stark contrast to their regular occurrence in North Lantau waters during the baseline period. This should be of a serious concern, and the occurrence of young calves in North Lantau waters should be closely monitored in the upcoming quarters.

Activities and Associations with Fishing Boats

3.5.41 Four of the 18 dolphin groups were engaged in feeding activities, while two other dolphin groups were engaged in socializing activities. None of the dolphin groups were engaged in traveling or milling/resting activity during the three-month study period.

3.5.42 The percentages of sightings associated with feeding activities (22.2%) and socializing activities (11.1%) during the present impact phase period were both higher than the ones recorded during the baseline period (11.6% and 5.4% respectively). However, it should be noted the sample sizes on total numbers of dolphin sightings were very different between the two periods

3.5.43 Distribution of dolphins engaged in various activities during the present three-month period and baseline period is shown in Figure 6 of Appendix J. The four dolphin groups engaged in feeding activities were sighted near Lung Kwu Chau and Sha Chau as well as to the north of Lung Kwu Chau (Figure 6 of Appendix J). The two groups engaged in socializing activities were both located to the west of Lung Kwu Chau (Figure 6 of Appendix J).

3.5.44 When compared to the baseline period, distribution of various dolphin activities during the present impact phase monitoring period was drastically different with a much more restricted area of occurrences.

3.5.45 As consistently recorded in the past monitoring quarters, none of the 18 dolphin groups was found to be associated with operating fishing vessels in North Lantau waters during the present impact phase period.

Summary Photo-identification works

3.5.46 From September to November 2015, over 2,500 digital photographs of Chinese White Dolphins were taken during the impact phase monitoring surveys for the photo-identification work.

3.5.47 In total, 34 individuals sighted 65 times altogether were identified (see summary table in Annex III of Appendix J and photographs of identified individuals in Annex IV of Appendix J). All of these re-sightings were made in NWL.

3.5.48 The majority of identified individuals were sighted only once or twice during the three-month period, with the exception of two individuals (NL46 and NL210) being 3-4 times and another three individuals (NL48, NL202 and NL286) being sighted 5-6 times.

3.5.49 Notably, eight of these 34 individuals (NL33, NL123, NL284, NL285, WL05, WL79, WL241 and WL243) were also sighted in West Lantau waters during the HKLR09 monitoring surveys from September to November 2015, implying that they have moved across the HKLR09 bridge alignment during the same three-month period.

Individual range use

3.5.50 Ranging patterns of the 34 individuals identified during the three-month study period were determined by fixed kernel method, and are shown in Annex V of Appendix J.

3.5.51 All identified dolphins sighted in the present quarter were utilizing NWL waters only, but have completely avoided NEL waters where many of them have utilized as their core areas in the past Annex V of Appendix J). This is in contrary to the extensive movements between NEL and NWL survey areas observed in the earlier impact monitoring quarters as well as the baseline period.

3.5.52 Notably, several individuals (NL33, NL123, NL284, NL285 and WL05) consistently utilized both NWL and NEL waters in the past have extended their range use to WL waters (and even SWL waters in the case of NL33) during the present quarter. In the upcoming quarters, individual range use and movements should be continuously monitored to examine whether there has been any consistent shifts of individual home ranges from North Lantau to West or Southwest Lantau, as such shift could possibly be related to the HZMB-related construction works (see Hung 2015).

Action Level / Limit Level Exceedance

3.5.53 There was two Action Level exceedances of dolphin monitoring for the quarterly monitoring data (between September - November 2015). According to the contractor’s information, the marine activities undertaken for HKLR03 during the quarter of September to November 2015 included reclamation, excavation of stone platform, construction of seawall, temporary drainage diversion and ground investigation. There is no evidence showing the current AL non-compliance directly related to the construction works of HKLR03 (where the amounts of working vessels for HKLR03 have been decreasing), although the generally increased amount of vessel traffic in NEL since the impact phase (October 2012). It should also be noted that reclamation work under HKLR03 (adjoining the Airport Island) situates in waters which has rarely been used by dolphins in the past, and the working vessels under HKLR03 have been travelling from source to destination in accordance with the Marine Travel Route to minimize impacts on Chinese White Dolphin. In addition, the contractor will implement proactive mitigation measures such as avoiding anchoring at Marine Department’s designated anchorage site – Sham Shui Kok Anchorage (near Brothers Island) as far as practicable.

3.5.54 A two-way ANOVA with repeated measures and unequal sample size was conducted to examine whether there were any significant differences in the average encounter rates between the baseline and impact monitoring periods. The two variables that were examined included the two periods (baseline and impact phases) and two locations (NEL and NWL).A).

3.5.55 For the comparison between the baseline period and the present quarter (12^th quarter of the impact phase being assessed), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.0079 and 0.071 respectively. If the alpha value is set at 0.05, significant differences were detected between the baseline and present quarters in dolphin encounter rate of STG, but not in the dolphin encounter rate of ANI.

3.5.56 For the comparison between the baseline period and the cumulative quarters in impact phase (i.e. first twelve quarters of the impact phase being assessed), the p-value for the differences in average dolphin encounter rates of STG and ANI were 0.00009 and 0.00003 respectively. Even if the alpha value is set at 0.001, significant differences were detected in both the average dolphin encounter rates of STG and ANI (i.e. between the two periods and the locations).

3.5.57 The AFCD monitoring data during September 2015 to November 2015 has been reviewed by the dolphin specialist. During the same quarter, no dolphin was sighted from 78.70 km of survey effort on primary lines in NEL, while seven groups of 24 dolphins were sighted from 144.11 km of survey effort on primary lines in NWL. This review has confirmed that the low occurrence of dolphins reported by the HKLR03 monitoring surveys in autumn 2015 in NEL and NWL survey area is accurate.

3.5.58 All dolphin protective measures are fully and properly implemented in accordance with the EM&A Manual. According to the Marine Travel Route Plan, if vessels are crossing along edge of the proposed marine park, the travelling speed will keep not exceeding 5 knots when crossing the edge of the proposed marine park. The Contractor will continue to provide training for skippers to ensure that their working vessels travel from source to destination to minimize impacts on Chinese White Dolphin and avoid anchoring at Marine Department’s designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as far as practicable. Also, it is recommended to complete the marine works of the Contract as soon as possible so as to reduce the overall duration of impacts and allow the dolphins population to recover as early as possible.

3.5.59 A meeting was held on 15 January 2016 with attendance of representative of Highways Department (HyD), ENPO, Resident Site Staff (RSS), Environmental Team (ET) and dolphin specialist for Contract Nos. HY/2010/02, HY/2011/03, HY/2012/07, HY/2012/08. Also, main Contractor for Contract Nos. HY/2012/07 and HY/2012/08 attended the meeting. The discussion/recommendation as recorded in the minutes of the meeting, which might be relevant to HKLR03 Contract are summarized below.

3.5.60 It was concluded that the HZMB works is one of the contributing factors affecting the dolphins. It was also concluded the contribution of impacts due to the HZMB works as a whole (or individual marine contracts) cannot be quantified nor separate from the other stress factors.

3.5.61 It was reminded that the ETs shall keep reviewing the implementation status of the dolphin related mitigation measures and remind the contractor to ensure the relevant measures were fully implemented.

3.5.62 It was recommended that the marine works of HZMB projects should be completed as soon as possible so as to reduce the overall duration of impacts and allow the dolphins population to recover as early as possible.

3.5.63 It was also recommended that the marine works footprint (e.g., reduce the size of peripheral silt curtain) and vessels for the marine works should be reduced as much as possible, and vessels idling / mooring in other part of the North Lantau shall be avoided whenever possible.

3.5.64 It was suggested that the protection measures (e.g., speed limit control) for the proposed Brothers Island Marine Park (BMP) shall be brought forward as soon as possible before its establishment so as to provide a better habitat for dolphin recovery. It was noted that under the Regular Marine Travel Route Plan, the contractors have committed to reduce the vessel speed in BMP. HyD updated that the proposed BMP will be gazetted in January 2016. The ETs were reminded to update the BMP boundary in the Regular Marine Travel Route Plan.

3.5.65 There was a discussion on exploring possible further mitigation measures, for example, controlling the underwater noise. It was noted that the EIA reports for the projects suggested several mitigation measures, all of which have been implemented.

3.6 Mudflat Monitoring Results

Sedimentation Rate Monitoring

3.6.1 The baseline sedimentation rate monitoring was in September 2012 and impact sedimentation rate monitoring was undertaken on 10 September 2015. The mudflat surface levels at the four established monitoring stations and the corresponding XYZ HK1980 GRID coordinates are presented in Table 3.9 and Table 3.10.

Table 3.9 Measured Mudflat Surface Level Results

	Baseline Monitoring (September 2012)			Impact Monitoring (September 2015)
Monitoring Station	Easting (m)	Northing (m)	Surface Level (mPD)	Easting (m)	Northing (m)	Surface Level (mPD)
S1	810291.160	816678.727	0.950	810291.167	816678.723	1.061
S2	810958.272	815831.531	0.864	810958.278	815831.542	0.960
S3	810716.585	815953.308	1.341	810716.595	815953.340	1.466
S4	811221.433	816151.381	0.931	811221.414	816151.336	1.004

Table 3.10 Comparison of Measurement

	Comparison of measurement			Remarks and Recommendation
Monitoring Station	Easting (m)	Northing (m)	Surface Level (mPD)	Remarks and Recommendation
S1	0.007	-0.004	0.111	Level continuously increased
S2	0.006	0.011	0.096	Level continuously increased
S3	0.010	0.032	0.125	Level continuously increased
S4	-0.019	-0.045	0.073	Level continuously increased

3.6.2 This measurement result was generally and relatively higher than the baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.

Water Quality Monitoring

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

3.6.4 Impact water quality monitoring in San Tau (monitoring station SR3) was conducted in September 2015. The monitoring parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).

3.6.5 The Impact monitoring result for SR3 were extracted and summarised below:

Table 3.11 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)
2-Sep-15	5.69	20.40	8.30	5.46	15.85	13.50
4-Sep-15	6.27	7.55	7.35	6.22	4.40	4.60
7-Sep-15	6.32	3.75	3.30	6.43	4.75	5.80
9-Sep-15	6.89	4.65	2.95	7.75	4.80	4.10
11-Sep-15	6.53	5.95	5.35	9.00	7.20	6.80
14-Sep-15	5.82	6.75	6.50	5.74	5.35	7.00
16-Sep-15	5.86	10.70	11.90	5.64	7.50	7.70
18-Sep-15	5.82	8.50	7.50	5.71	6.70	6.20
21-Sep-15	6.07	6.30	5.30	6.58	3.80	2.70
23-Sep-15	6.15	3.80	2.45	7.39	3.30	2.60
25-Sep-15	6.63	5.20	5.90	8.23	10.05	5.20
28-Sep-15	5.27	7.65	7.90	6.04	8.05	8.55
30-Sep-15	5.64	17.15	13.75	5.47	12.45	16.00
Average	6.07	8.33	6.80	6.59	7.25	6.98

Mudflat Ecology Monitoring

Sampling Zone

3.6.6 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 O). The horizontal length of sampling zones TC1, TC2, TC3 and ST were about 250 m, 300 m, 300 m and 250 m, respectively. Survey of horseshoe crabs, seagrass beds and intertidal communities were conducted in every sampling zone. The present survey was conducted in September 2015 (totally 5 sampling days between 5^th and 13^th September 2015The locations of sampling zones are shown in Annex I of Appendix O.

Horseshoe Crabs

3.6.7 Active search method was conducted for horseshoe crab monitoring by two experienced surveyors at every sampling zone. During the search period, any accessible and potential area would be investigated for any horseshoe crab individuals within 2-3 hours in 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 6^th (for TC1), 10^th(for TC3 and ST) and 12^th (for TC2) September 2015. During the survey period, the weather was hot and sunny in TC1, TC3 and ST while it was rainy in TC2.

Seagrass Beds

3.6.8 Active search method was conducted for seagrass bed monitoring by two experienced surveyors at every sampling zone. During the search period, any accessible and potential area would be investigated for any seagrass beds within 2-3 hours in low tide period. Once seagrass bed was found, the species, estimated area, estimated coverage percentage and respective GPS coordinate were recorded. A photographic record was taken for future investigation. The seagrass beds surveys were conducted on 6^th (for TC1), 10^th (for TC3 and ST) and 12^th (for TC2) September 2015. During the survey period, the weather was hot and sunny in TC1, TC3 and ST while it was rainy in TC2.

Intertidal Soft Shore Communities

3.6.9 The intertidal soft shore community surveys were conducted in low tide period on 5^th (for ST), 6^th(for TC1), 12^th(for TC2) and 13^thSeptember 2015 (for TC3). At each sampling zone, three 100 m horizontal transects 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, ten random quadrats (0.5 m x 0.5m) were placed.

3.6.10 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 were dug for visible infauna in the quadrat regardless of hand core sample was taken.

3.6.11 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.

3.6.12 The taxonomic classification was conducted in accordance to the following references: Polychaetes: Fauchald (1977), Yang and Sun (1988); Arthropods: Dai and Yang (1991), Dong (1991); Mollusks: Chan and Caley (2003), Qi (2004).

Data Analysis

3.6.13 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’= -Σ ( Ni / N ) ln ( Ni / N ) (Shannon and Weaver, 1963)

J = H’ / ln S, (Pielou, 1966)

where S is the total number of species in the sample, N is the total number of individuals, and Ni is the number of individuals of the i^th species.

Mudflat Ecology Monitoring Results and Conclusion

Horseshoe Crabs

3.6.14 In general, two species of horseshoe crab Carcinoscorpius rotundicauda (total 196 ind.) and Tachypleus tridentatus (total 10 ind.) were recorded in the survey area. Individuals were mainly found on fine sand while few were found on soft mud. The group size varied from 2 to 26 individuals for every sight record. Although less number of Tachypleus tridentatus was recorded, the average body size was larger than that of Carcinoscorpius rotundicauda. Photo records were shown in Figure 3.1 of Appendix O while the complete records of horseshoe crab survey in every sampling zone were shown in Annex II of Appendix O.

3.6.15 One big individual of Carcinoscorpius rotundicauda was found trapped in a trash fish net (Figure 3.1 of Appendix O) on ST shore (GPS coordinate: 22° 17.385' N, 113° 55.460' E). Its prosomal width reached 130.77 mm. After photo recording, it was released to water. This big individual should have had migrated to sub-tidal habitat. It might forage on intertidal habitat occasionally during high tide period. Since intertidal soft shore was no longer a nursery ground for this individual, its record was excluded from the data analysis. It was to avoid mixing up with juvenile population living on soft shore.

3.6.16 Table 3.1 of Appendix O summarizes the survey results of horseshoe crab in present survey. For Carcinoscorpius rotundicauda, it could be found in all sampling zones while more individuals were recorded in TC3 and ST (TC1: 41 ind., TC2: 4 ind., TC3: 70 ind., ST: 81 ind.). The search record was 10.3 ind. hr^-1 person^-1, 1.0 ind. hr^-1 person^-1, 11.7 ind. hr^-1 person^-1, 13.5 ind. hr^-1 person^-1 in TC1, TC2, TC3 and ST respectively. The size of individuals was similar among TC1 (mean prosomal width: 39.58 mm), TC2 (36.20 mm) and ST (37.03mm) while that of TC3 was smaller (27.27 mm).

3.6.17 For Tachypleus tridentatus, it could be found in TC3 (1 ind.) and ST (9 ind.) only. The search records were 0.2 ind. hr^-1 person^-1 and 1.5 ind. hr^-1 person^-1 in TC3 and ST respectively. The mean prosomal width of TC3 (53.90 mm) was larger than that of ST (48.50mm).

3.6.18 In the previous survey of March 2015, there was one important finding that a mating pair of Carcinoscorpius rotundicauda was found in ST (prosomal width: male 155.1 mm, female 138.2 mm) (Figure 3.2 of Appendix O). It indicated the importance of ST as a breeding ground of horseshoe crab. Moreover, two moults of Carcinoscorpius rotundicauda were found in TC1 with similar prosomal width 130-140 mm (Figure 3.2 of Appendix O). It reflected that a certain numbers of moderately sized individuals inhabited the sub-tidal habitat of Tung Chung Wan after its nursery period on soft shore. These individuals might move onto soft shore during high tide for feeding, moulting and breeding. Then it would return to sub-tidal habitat during low tide. Because the mating pair should be inhabiting sub-tidal habitat in most of the time. The record was excluded from the data analysis to avoid mixing up with juvenile population living on soft shore.

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

3.6.20 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

3.6.21 Figures 3.3 and 3.4 of Appendix O 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 along the sampling months. In general, higher search records (i.e. number of individuals) of both species were always found in ST followed by TC3 from September 2012 to September 2014. Then the search record in TC3 was even higher than that in ST from March 2015 to June 2015. In this sampling month (Sep. 2015), highest search record was found in ST again. For TC1, the search record was at low to medium level and fluctuated slightly along the sampling months. In contrast, much lower search record was found in TC2 (2 ind. in September 2013, 1 ind. in March, June, September. 2014, March and June 2015, 4 ind. in September. 2015). For spatial difference of horseshoe crab size, larger individuals were usually found in ST while smaller individuals were usually found in TC3.

3.6.22 Throughout the monitoring period conducted, it was obvious that TC3 and ST (western shore of Tung Chung Wan) was an important nursery ground for horseshoe crab especially newly hatched individuals due to larger area of suitable substratum (fine sand or soft mud) and less human disturbance (far from urban district). Relatively, other sampling zones were not a suitable nursery ground especially TC2. Possible factors were less area of suitable substratum (especially TC1) and higher human disturbance (TC1 and TC2: close to urban district and easily accessible). In TC2, large daily salinity fluctuation was a possible factor either since it was flushed by two rivers under tidal inundation. The individuals inhabiting TC1 and TC2 were confined in small moving range due to limited area of suitable substrata during the nursery period.

Seasonal variation of horseshoe crab population

3.6.23 Throughout the monitoring period conducted, the search record of horseshoe crab declined obviously during dry season especially December (Figures 3.3 and 3.4 of Appendix O). In December 2013, no individual of horseshoe crab was found. In December 2014, 2 individuals of Carcinoscorpius rotundicauda and 8 individuals of Tachypleus tridentatus were found only. The horseshoe crabs were inactive and burrowed in the sediments during cold weather (<15 ºC). Similar results of low search record in dry season were reported in a previous territory-wide survey of horseshoe crab. For example, the search records in Tung Chung Wan were 0.17 ind. hr^-1 person^-1 and 0.00 ind. hr^-1 person^-1 in wet season and dry season respectively (details see Li, 2008). After the dry season, the search record increased with the warmer climate.

3.6.24 Between the sampling months September 2012 and December 2013, Carcinoscorpius rotundicauda was a less common species relative to Tachypleus tridentatus. Only 4 individuals were ever recorded in ST in December 2012. This species had ever been believed of very low density in ST hence the encounter rate was very low. Since March. 2014, it was found in all sampling zones with higher abundance in ST. Based on its average size (mean prosomal width 39.28-49.81 mm), it indicated that breeding and spawning of this species had occurred about 3 years ago along the coastline of Tung Chun Wan. However, these individuals were still small while their walking trails were inconspicuous. Hence there was no search record in previous sampling months. From March 2014 to September 2015, more individuals were recorded due to larger size and higher activity.

3.6.25 For Tachypleus tridentatus, sharp increase of number of individuals was recorded in ST with wet season (from March to September 2013). 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 during the wet season of 2014. The number of individuals increased in March and June 2014 followed by a rapid decline in September 2014. Then the number of individuals showed a general decreasing trend from March. 2014 to June 2015. Apart from natural mortality, migration from nursery soft shore to subtidal habitat was another possible cause. Since the mean prosomal width of Tachypleus tridentatus continued to grow and reached about 50 mm since March 2014. Then it varied slightly between 50-65 mm from September 2014 to September 2015. Most of the individuals might have reached a suitable size strong enough to forage in sub-tidal habitat.

3.6.26 Since TC3 and ST were regarded as important nursery ground for horseshoe crab, 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

3.6.27 Figure 3.5 of Appendix O shows the changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus tridentatus in TC3. As mentioned above, Carcinoscorpius rotundicauda was rarely found between September 2012 and December 2013 hence the data were lacking. In March 2014, the major size (50% of individual records between upper and lower quartile) ranged 40-60 mm while only few individuals were found. From March 2014 to September 2015, the size of major population decreased and more small individuals were recorded after March of every year. It indicated new rounds of successful breeding and spawning of Carcinoscorpius rotundicauda in TC3. It matched with the previous mating record in ST in March 2015.

3.6.28 For Tachypleus tridentatus, the major size ranged 20-50 mm while the number of individuals found fluctuated from September 2012 to June 2014. Then a slight but consistent growing trend was observed. The prosomal width increased from 25-35 mm in September 2014 to 35-65 mm in June 2015. 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. In September 2015 (present survey), there was only one individual recorded in TC3.

Box plot of horseshoe crab populations in ST

3.6.29 Figure 3.6 of Appendix O shows the changes of prosomal width of Carcinoscorpius rotundicauda and Tachypleus tridentatus in ST. As mentioned above, Carcinoscorpius rotundicauda was rarely found between September 2012 and December 2013 hence the data were lacking. From Mar. 2014 to Sep. 2015, the size of major population decreased and more small individuals were recorded after Jun. of every year. It indicated new rounds of successful breeding and spawning of Carcinoscorpius rotundicauda in ST. It matched with the previous mating record in ST in Mar. 2015. Because the newly hatched individuals (prosomal width ~5mm) would take about half year to grow to a size with conspicuous walking trail.

3.6.30 For Tachypleus tridentatus, a consistent growing trend was observed for the major population from December 2012 to December 2014 regardless of change of search record. The prosomal width increased from 15-30 mm to 55-70 mm. As mentioned, the large individuals might have reached a suitable size for migrating from the nursery soft shore to subtidal habitat. From March to June 2015, the size of major population decreased slightly with prosomal width 40-60 mm. It further indicated some of order individuals might have migrated to sub-tidal habitat. From March to September 2015, the size of major population decreased slightly to a prosomal width 40-60 mm. At the same time, the number of individuals decreased gradually. It further indicated some of large individuals might have migrated to sub-tidal habitats.

3.6.31 As a summary for horseshoe crab populations in TC3 and ST, there was successful spawning of Carcinoscorpius rotundicauda from 2014 to 2015. The spawning time should be in spring while the major spawning month might be different slightly between two zones. There were consistent, increasing trends of population size in these two sampling zones. For Tachypleus tridentatus, small individuals were rarely found TC3 and ST 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. It was expected the population would remain at low level until new round of successful spawning.

Impact of the HKLR project

3.6.32 The present survey was the 12^th survey of the EM&A programme during the construction period. Based on the results, impact of the HKLR project could not be detected on horseshoe crabs considering the factor of natural, seasonal variation. In case, abnormal phenomenon (e.g. very few numbers of horseshoe crab individuals in warm weather, large number of dead individuals on the shore) is observed, it would be reported as soon as possible.

Seagrass Beds

3.6.33 In general, two species of seagrass Halophila ovalis and Zostera japonica were recorded in ST only. Both species were found on sandy substratum nearby the seaward side of mangrove vegetation at 2.0 m above C.D. Two species were found coexisting in two seagrass beds. Photo records were shown in Figure 3.7 of Appendix O while the complete records of seagrass beds survey were shown in Annex III of Appendix O.

3.6.34 Table 3.2 of Appendix O summarize the results of seagrass beds survey in ST. Four patches of Halophila ovalis were found while the total seagrass bed area was about 91.4 m² (average area 22.8 m²). The largest patch was a long strand with seagrass bed area 32.0 m² and variable vegetation coverage 10-80%. Two other patches were smaller strands (17.4 and 26.3 m²) with variable vegetation coverage 30-60%. Both had co-existing seagrass Zostera japonica. The smallest patch was about 15.8 m² with highest percentage coverage 80%. For Zostera japonica, there were two long strands (17.4-26.3 m²) of seagrass beds with low coverage percentage 10-20%. Both long strands had co-existing seagrass Halophila ovalis. The total seagrass bed area was about 43.7 m² (average area 21.8 m²).

Temporal variation of seagrass beds

3.6.35 Figure 3.8 of Appendix O 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 March 2013 that grew within the large patch of seagrass Halophila ovalis. Then the patch size increased and merged gradually with the warmer climate from March to June 2013 (15 m²). However the patch size decreased sharply and remained similar from September 2013 (4 m²) to March 2014 (3 m²). In June 2014, the patch size increased obviously again (41 m²) with warmer climate. Similar to previous year, the patch size decreased again and remained similar September 2014 (2 m²) to December 2014 (5 m²). From March to June 2015, the patch size increased sharply again (90.0 m²). It might be due to the disappearance of the originally dominant seagrass Halophila ovalis resulting in less competition for substratum and nutrients. In September 2015, the patch size decreased and was found coexisting with seagrass Halophila ovalis. In general, the seagrass bed of Zostera japonica fluctuated in patch size along the sampling months.

3.6.36 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 the September 2012 (First survey). The total seagrass bed area grew steadily from 332.3 m² in September 2012 to 727.4 m² in December 2013. Flowers could be observed in the largest patch during its flowering period in December 2013. In March 2014, 31 small to medium patches were newly recorded (variable area 1-72 m² per patch, vegetation coverage 40-80% per patch) in lower tidal zone between 1.0 and 1.5 m above C.D. The total seagrass area increased further to 1350 m². In June 2014, these small and medium patches grew and extended to each others. These patches were no longer distinguishable and were covering a significant mudflat area of ST. It was generally grouped into 4 large areas (1116 – 2443 m²) of seagrass beds characterized of patchy distribution, variable vegetable coverage (40-80%) and smaller leaves. The total seagrass bed area increased sharply to 7629 m². In September 2014, the total seagrass area declined sharply to 1111 m². There were only 3-4 small to large patches (6 - 253 m²) at high tidal level and 1 patch at low tidal level (786 m²). Typhoon or strong water current was a possible cause (Fong, 1998). In September 2014, there were two tropical cyclone records in Hong Kong (7^th-8^th September: no cyclone name, maximum signal number 1; 14^th-17^th September: Kalmaegi maximum signal number 8SE) before the seagrass survey dated 21^st September 2014. The strong water current caused by the cyclone, Kalmaegi especially, might have given damage to the seagrass beds. In addition, natural heat stress and grazing force were other possible causes reducing seagrass beds area. Besides, Halophila ovalis could be found in other mud flat area surrounding the single patch. But it was hardly distinguished into patches due to very low coverage (10-20%) and small leaves.

3.6.37 In December 2014, all the seagrass patches of Halophila ovalis disappeared in ST. Figure 3.9 of Appendix O shows the difference of the original seagrass beds area nearby the mangrove vegetation at high tidal level between June 2014 and December 2014. Such rapid loss would not be seasonal phenomenon because the seagrass beds at higher tidal level (2.0 m above C.D.) were present and normal in December 2012 and 2013. According to Fong (1998), similar incident had occurred in ST in the past. The original seagrass area had declined significantly during the commencement of the construction and reclamation works for the international airport at Chek Lap Kok in 1992. The seagrass almost disappeared in 1995 and recovered gradually after the completion of reclamation works. Moreover, incident of rapid loss of seagrass area was also recorded in another intertidal mudflat in Lai Chi Wo in 1998 with unknown reason. Hence Halophila ovalis was regarded as a short-lived and r-strategy seagrass that can colonize areas in short period but disappears quickly under unfavourable conditions (Fong, 1998).

Unfavourable conditions to seagrass Halophila ovalis

3.6.38 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 September 2014. The strong water current caused by the cyclones might have given damage to the seagrass beds.

3.6.39 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).

3.6.40 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 September, 2014, the SS concentrations measured at 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 September 2014 (daily total rainfall at the Hong Kong International Airport: 0-2.1 mm; extracted from the climatological data of Hong Kong Observatory). The effect of upstream runoff on water quality should be neglectable in that period. Moreover the exceedance of water quality was considered unlikely to be related to the contract works of HKLR according to the ‘Notifications of Environmental Quality Limits Exceedances’ provided by the respective environmental team. The respective construction of seawall and stone column works, which possibly caused turbid water, 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.

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

3.6.42 From March to June 2015, 2-3 small patches of Halophila ovalis were newly found coinhabiting with another seagrass species Zostera japonica. But its total patch area was still very low relative to the previous records. The recolonization rate was low while cold weather and insufficient sunlight were possible factors between December 2014 and March 2015. Moreover, it would need to compete with more abundant 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. In September 2015, the total seagrass area of Halophila ovalis had increased rapidly from 6.8 m² to 91.35 m². It had recolonized its original patch locations and covered Zostera japonica. Hence it was expected that the seagrass bed of Halophila ovalis would increase continually in the following months.

Impact of the HKLR project

3.6.43 The present survey was the 12^th survey of the EM&A programme during the construction period. According to the results of present survey, there was recolonization of both seagrass species Halophila ovalis and Zostera japonica in ST. The seagrass patches were believed in recovery. Hence the negative impact of HKLR project on the seagrass was not significant. In case, adverse phenomenon (e.g. reduction of seagrass patch size, abnormal change of leave colour) is observed again, it would be reported as soon as possible.

Intertidal Soft Shore Communities

3.6.44 Table 3.3 and Figure 3.10 of Appendix O show the types of substratum along the horizontal transect at every tidal level in every sampling zone. The relative distribution of different substrata was estimated by categorizing the substratum types (Gravels & Boulders / Sands / Soft mud) of the ten random quadrats along the horizontal transect. The distribution of substratum types varied among tidal levels and sampling zones:

· In TC1, high percentage of ‘Sands’ (70%) was recorded at high tidal level which was different from previous records (high percentage of ‘Gravels and Boulders’). By direct observation on site, there was no obvious change of substratum at high tidal level. Hence it was simply due to more random quadrats laid on sandy substratum in this sampling. High percentage of ‘Gravels and Boulders’ was recorded (80-100%) at mid and low tidal levels.

· In TC2, the substratum distribution was different between tidal levels. At high tidal level, higher percentage of ‘Sands’ (60%) was recorded followed by ‘Soft mud’ (30%). At mid tidal level, higher percentage of ‘Sands’ (70%) was recorded followed by ‘Gravels and Boulders’ (30%). At low tidal level, higher percentage of ‘Soft mud’ (60%) was recorded followed by ‘Sands’ (40%).

· In TC3, the substratum type was clearly different between high-mid tidal level and low tidal level. ‘Sands’ was the main substratum type (90-100%) at high and mid tidal levels while ‘Gravels and Boulders’ was the main substratum type (100%) at low tidal level.

· In ST, the substratum type was clearly different between high-mid tidal level and low tidal level. ‘Gravels and Boulders’ (90-100%) was the main substratum at high and mid tidal levels. At low tidal level, higher percentage of ‘Sands’ (70%) was recorded followed by ‘Gravels and Boulders’ (30%).

3.6.45 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.

3.6.46 Table 3.4 of Appendix O lists the total abundance, density and number of taxon of every phylum in this survey. A total of 12502 individuals were recorded. Mollusca was significantly the most abundant phylum (total individuals 11994, density 400 ind. m^-2, relative abundance 95.9%). The second abundant phylum was Arthropoda (383 ind., 13 ind. m^-2, 3.1%). The third and fourth abundant phyla were Annelida (71 ind., 2 ind. m^-2, 0.6%) and Sipuncula (23 ind., 1 ind. m^-2, 0.2%). Relatively other phyla were very low in abundances (density £1 ind. m^-2, relative abundance £0.1%). Moreover, the most diverse phylum was Mollusca (35 taxa) followed by Arthropoda (13 taxa) and Annelida (9 taxa). There was 1 taxon recorded only for other phyla. The complete list of collected specimens is shown in Annex V of Appendix O.

3.6.47 Table 3.5 of Appendix O show the number of individual, relative abundance and density of each phylum in every sampling zone. The total abundance (2454-4506 ind.) varied among the four sampling zones while the phyla distributions were similar. In general, Mollusca was the most dominant phylum (no. of individuals: 2359-4297 ind.; relative abundance 94.9-98.0%; density 315-573 ind. m^-2). Other phyla were significantly lower in number of individuals. Arthropoda was the second abundant phylum (35-169 ind.; 1.4-3.8%; 5-23 ind. m^-2). Annelida was the third abundant phylum (32-35 ind.; 0.8-1.1%; 4-5 ind. m^-2) in TC2 and TC3. Sipuncula was the third or fourth abundant phylum (8-9 ind.; 0.3%; 1 ind. m^-2) in TC1 and TC2. Cnidaria (sea anemone) was the third abundant phylum (12 ind.; 0.5%; 2 ind. m^-2) in ST. Relatively other phyla were low in abundance among the four sampling zones (≤ 0.3%).

Dominant species in every sampling zone

3.6.48 Table 3.6 of Appendix O lists the abundant species (relative abundance >10%) in every sampling zone. In TC1, gastropod Batillaria multiformis was the most abundant species (54 ind. m^-2, relative abundance 29%) followed by gastropods Cerithidea djadjariensis (47 ind. m^-2, 25%) and Cerithidea cingulata (38 ind. m^-2, 20%) at high tidal level (major substratum: ‘Sands’). However all abundant species were at low density relative to other sampling zones. At mid tidal level (major substratum: ‘Gravels and Boulders’), the abundant species were gastropods Monodonta labio (112 ind. m^-2, 34%), Batillaria multiformis (79 ind. m^-2, 24%) and rock oyster Saccostrea cucullata (72 ind. m^-2, 22%, attached on boulders) at low-moderate densities. At low tidal level (major substratum: ‘Gravels and Boulders’), gastropod Monodonta labio (242 ind. m^-2, 47%) and rock oyster Saccostrea cucullata (121 ind. m^-2, 24%) were abundant at moderate-high densities.

3.6.49 At TC2, gastropod Cerithidea djadjariensis (407 ind. m^-2, 53%) was the most abundant at high density followed by Cerithidea cingulata (157 ind. m^-2, 20%) at high tidal level (major substratum: ‘Sands’). Relative to high tidal level, the density of every taxon was much lower and similar at mid and low tidal levels. No dominant species was determined. At mid tidal level (major substratum: ‘Sands’), rock oyster Saccostrea cucullata (76 ind. m^-2, 25%, attached on boulders), gastropods Batillaria zonalis (73 ind. m^-2, 24%), Monodonta labio (44 ind. m^-2, 15%) and Cerithidea djadjariensis (31 ind. m^-2, 10%) were commonly occurring at low density. At low tidal level (major substratum: ‘Soft mud’), Batillaria zonalis (41 ind. m^-2, 34%), rock oyster Saccostrea cucullata (24 ind. m^-2, 20%) and barnacle Balanus amphitrite (19 ind. m^-2, 16%, attached on boulders) were commonly occurring at low density.

3.6.50 At TC3, the abundant species were similar with variable densities at high and mid tidal levels (major substratum: ‘Sands’). There were gastropods Cerithidea djadjariensis (146-257 ind. m^-2, 25-35%), Batillaria multiformis (143-256 ind. m^-2, 25-35%) and Cerithidea cingulata (128-222 ind. m^-2, 18-39%) at moderate densities. At low tidal level (major substratum: ‘Gravels and Boulders’), gastropod Monodonta labio (197 ind. m^-2, 39%) and rock oyster Saccostrea cucullata (146 ind. m^-2, 29%, attached on boulders) were abundant at moderate densities. Little black mussel Xenostrobus atratus (48 ind. m^-2, 10%) was the third abundant species at low density.

3.6.51 At ST, gastropod Monodonta labio (130-145 ind. m^-2, 34-38%) and rock oyster Saccostrea cucullata (80-91 ind. m^-2, 21-24%, attached on boulders) were the abundant species of low-moderate densities at high and mid tidal levels (major substratum: ‘Gravels and Boulders’). Gastropods Batillaria multiformis (76 ind. m^-2, 20%) and Lunella coronata (45 ind. m^-2, 12%) were the third abundant species at high tidal level and mid tidal level respectively. At low tidal level (major substratum: ‘Sands’), rock oyster Saccostrea cucullata (71 ind. m^-2, 33%) was the most abundant followed by gastropods Lunella coronata (41 ind. m^-2, 19%) and Euchelus scaber (30 ind. m^-2, 14%). All three species were at low densities.

3.6.52 In general, there was no consistent zonation pattern of species distribution observed across all sampling zones and tidal levelsThe species distribution should be determined by the type of substratum primarily. In general, gastropods Cerithidea djadjariensis (total number of individuals: 2350 ind., relative abundance 18.8%), Batillaria multiformis (1757 ind., 14.1%), and Cerithidea cingulata (1561 ind., 12.5%) and Batillaria zonalis (468 ind., 3.7%) were the most commonly occurring species on sandy and soft mud substrata. Gastropods Monodonta labio (2249 ind., 18.0%), Lunella coronata (408 ind., 3.3%) and rock oyster Saccostrea cucullata (1930 ind., 15.4%) were commonly occurring species inhabiting gravel and boulders substratum.

3.6.53 Relative to the results of previous sampling (June 2015), the densities of gastropod Batillaria multiformis declined sharply in TC1, TC3 and ST. Heat stress was one possible cause of population decline. According to the online database of Hong Kong Observatory, there were 14, 13 and 18 days with ‘Very Hot Weather Warning’ in June, July and August 2015 respectively (total 45 days) with mean monthly ambient temperature 29.1-29.7 ˚C. Moreover majority of low tide period occurs in day time of summer (especially afternoon) in Hong Kong. The substratum between mid and high tidal levels would be strongly heated under direct sunshine with little water splashing. Since this gastropod species usually inhabits at high and mid tidal levels, high mortality rate would be resulted. Its population was believed to be restored gradually during dry season.

Biodiversity and abundance of soft shore communities

3.6.54 Table 3.7 of Appendix O shows the mean values of number of species, density, biodiversity index H’ and species evenness J of soft shore communities at every tidal level and in every sampling zone. Among the sampling zones, the mean species number (10 spp. 0.25 m^-2) and mean H’ (1.6) in ST were slightly higher than other sampling zones (mean species number: 8 spp. 0.25 m^-2, H’ 1.3-1.4). The mean densities were quite variable among sites. The mean density of TC3 (601 ind. m^-2) was higher than other sampling zones (327-398 ind. m^-2). However mean J showed no clear difference among sampling zones (0.6-0.7).

3.6.55 Across the tidal levels, there was no consistent difference of the mean number of species, H’ and J in all sampling zones. For the mean density, a general decreasing trend was observed from high tidal level to low tidal level at TC2, TC3 and ST. At TC1, the mean density at low tidal level was higher than that at high and mid tidal levels. As mentioned, the variation of mean density should be determined by the type of substratum primarily.

3.6.56 Figures 3.11 to 3.14 of Appendix O show the temporal changes of mean number of species, mean density, H’ and J at every tidal level and in every sampling zone along the sampling months. From Jun. to Sep. 2015, the mean densities decreased clearly at high tidal level in TC1 and ST. As mentioned, it was due to higher mortality of dominant gastropod Batillaria multiformis under heat stress of wet season. Overall no consistent temporal change of any biological parameters was observed. All the parameters were under slight and natural fluctuation with the seasonal variation.

Impact of the HKLR project

3.6.57 The present survey was the 12^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. In case, abnormal phenomenon (e.g. large reduction of fauna densities and species number) is observed, it would be reported as soon as possible.

3.7 Solid and Liquid Waste Management Status

3.7.1 The Contractor registered with EPD as a Chemical Waste Producer on 12 July 2012 for the Contract. Sufficient numbers of receptacles were available for general refuse collection and sorting.

3.7.2 The summary of waste flow table is detailed in Appendix K.

3.7.3 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 Practise on the Packaging, Labelling and Storage of Chemical Wastes.

3.8 Environmental Licenses and Permits

3.8.1 The valid environmental licenses and permits during the reporting period are summarized in Appendix L.

4 Environmental Complaint and Non-compliance

4.1 Environmental Exceedances

4.1.1 The detailed air quality, noise, water quality and dolphin exceedances are provided in Appendix M. Also, the summaries of the environmental exceedances are presented as follows:

Air Quality

4.1.2 There were no Action/ Limit Level exceedances of 1-hour TSP and 24-hour TSP at AMS5 and AMS6 during the reporting period.

Noise

4.1.3 There were no Action/Limit Level exceedances for noise during daytime on normal weekdays of the reporting period.

Water Quality

4.1.1 For marine water quality monitoring, ten Action Level exceedances of suspended solid level were recorded during the reporting period. No Limit Level exceedance of suspended solid level was recorded. No Action Level/ Limit Level exceedance of turbidity level and dissolved oxygen level were recorded during the reporting period.

4.1.2 The construction activities were carried out within silt curtain as recommended in the EIA Report. There were no specific activities recorded during the monitoring period that would cause any significant impacts on the monitoring results. The exceedance of suspended solid level was considered to be attributed to other external factors, rather than the contract works. Therefore, the exceedance was considered as non-contract related. The detailed numbers of exceedances recorded during the reporting period at each impact station are summarised in Table 4.1.

Dolphin

4.1.3 There was two Action Level exceedances of dolphin monitoring for the quarterly monitoring data (between September - November 2015). According to the contractor’s information, the marine activities undertaken for HKLR03 during the quarter of September to November 2015 included reclamation, excavation of stone platform, construction of seawall, temporary drainage diversion and ground investigation.

4.1.4 There is no evidence showing the current AL non-compliance directly related to the construction works of HKLR03 (where the amounts of working vessels for HKLR03 have been decreasing), although the generally increased amount of vessel traffic in NEL since the impact phase (October 2012). It should also be noted that reclamation work under HKLR03 (adjoining the Airport Island) situates in waters which has rarely been used by dolphins in the past, and the working vessels under HKLR03 have been travelling from source to destination in accordance with the Marine Travel Route to minimize impacts on Chinese White Dolphin. In addition, the contractor will implement proactive mitigation measures such as avoiding anchoring at Marine Department’s designated anchorage site – Sham Shui Kok Anchorage (near Brothers Island) as far as practicable.

4.1.5 All dolphin protective measures are fully and properly implemented in accordance with the EM&A Manual. According to the Marine Travel Route Plan, if vessels are crossing along edge of the proposed marine park, the travelling speed will keep not exceeding 5 knots when crossing the edge of the proposed marine park. The Contractor will continue to provide training for skippers to ensure that their working vessels travel from source to destination to minimize impacts on Chinese White Dolphin and avoid anchoring at Marine Department’s designated anchorage site - Sham Shui Kok Anchorage (near Brothers Island) as far as practicable. Also, it is recommended to complete the marine works of the Contract as soon as possible so as to reduce the overall duration of impacts and allow the dolphins population to recover as early as possible.

Table 4.1 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	--	--	--	--	--	--	25 Nov 2015	25 Nov 2015	1	1
IS5	Limit Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)6	Action Level	--	--	--	--	--	--	25 Nov 2015	25 Nov 2015	1	1
IS(Mf)6	Limit Level	--	--	--	--	--	--	--	--	0	0
IS7	Action Level	--	--	--	--	--	--	--	25 Nov 2015	0	1
IS7	Limit Level	--	--	--	--	--	--	--	--	0	0
IS8	Action Level	--	--	--	--	--	--	--	--	0	0
IS8	Limit Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)9	Action Level	--	--	--	--	--	--	--	--	0	0
IS(Mf)9	Limit Level	--	--	--	--	--	--	--	--	0	0
IS10	Action Level	--	--	--	--	--	--	--	2 Oct 2015	0	1
IS10	Limit Level	--	--	--	--	--	--	--	--	0	0
SR3	Action Level	--	--	--	--	--	--	25 Nov 2015	25 Nov 2015	1	1
SR3	Limit Level	--	--	--	--	--	--	--	--	0	0
SR4	Action Level	--	--	--	--	--	--	--	11 Sep 2015	0	1
SR4	Limit Level	--	--	--	--	--	--	--	--	0	0
SR5	Action Level	--	--	--	--	--	--	--	2 Oct 2015	0	1
SR5	Limit Level	--	--	--	--	--	--	--	--	0	0
SR10A	Action Level	--	--	--	--	--	--	--	--	0	0
SR10A	Limit Level	--	--	--	--	--	--	--	--	0	0
SR10B	Action Level	--	--	--	--	--	--	--	--	0	0
SR10B	Limit Level	--	--	--	--	--	--	--	--	0	0
Total	Action	0	0	0	0	0	0	3	7	10**
Total	Limit	0	0	0	0	0	0	0	0	0**

Notes:

S: Surface;

M: Mid-depth;

** The total exceedances.

4.2 Summary of Environmental Complaint, Notification of Summons and Successful Prosecution

4.2.1 There was one complaint received during the reporting period. The summary of environmental complaints is presented in Table 4.2. The details of cumulative statistics of Environmental Complaints are provided in Appendix N.

Table 4.2 A Summary of Environmental Complaints for the Reporting Period

Environmental Complaint No.	Date of Complaint Received	Description of Environmental Complaints
COM-2015-079	7 December 2015	Water Quality

4.2.2 No notification of summons and prosecution was received during the reporting period.

4.2.3 Statistics on notifications of summons and successful prosecutions are summarized in Appendix M.

5 Comments, Recommendations and Conclusion

5.1 Comments

5.1.1 According to the environmental site inspections undertaken during the reporting period, the following recommendations were provided:

§ The Contractor was reminded to place additional sand bags along the boundary of dusty material at N1.

§ The Contractor was reminded to replace the broken sand bags at N20.

§ The Contractor was reminded to provide water spraying for drilling activities at S8 and breaking activity/ excavation works at S16.

§ The Contractor was reminded to spray water regularly on the unpaved road at S16.

§ The Contractor was reminded to provide a proper cover for drilling machines to avoid dust emission at S15.

§ The Contractor was reminded to repair the shelter of cement storage area to minimise dust emission at S11;

§ The Contractor was reminded to cover the bags of cement provide cover on the dump truck at HMA of Portion Y.

§ The Contractor was reminded to seal the holes of the water barriers at WA6.

§ The Contractor was reminded to provide proper noise barriers at S16.

§ The Contractor was reminded to cover the engine cover at all times during its operation at S15.

§ The Contractor was reminded to maintain the silt curtain in accordance with the design plan at Portion X.

§ The Contractor was reminded to place sand bags around the storage area of aggregate/clay at vessel Shun Tat 82.

§ The Contractor was reminded to seal the gap completely to avoid seepage of untreated water to water body at S11.

§ The Contractor was reminded to remove the concrete rubbles and dusty materials and prevent washing away the dusty materials into the sea at S7.

§ The Contractor was reminded to replace/provide sandbags to the edge of S7 to prevent washing away sand and the leakage of the muddy water into the sea at S7.

§ The Contractor was reminded to clean up the surface runoff at N1.

§ The Contractor was reminded to reconnect the wastewater treatment plant to provide the waste water treatment at S25.

§ The Contractor was reminded to collect the muddy water for treatment prior to discharge at S25.

§ The Contractor was reminded to provide sand bags along the site boundary at S25.

§ The Contractor was reminded to conduct and record the inspection record of sewage treatment plant accordingly.

§ The Contractor was reminded to block the site entrance /exit or provide a wheel wash facility for the site entrance/exit at S8.

§ The Contractor was reminded to provide a labour to wash wheels at WA4.

§ The Contractor was reminded to clean the obstacle in the wheel washing bay at S23.

§ The Contractor was reminded to place sand bags along the road at N20.

§ The Contractor was reminded to provide a proper wheel washing facility and provide wheel washing for the dump truck before leaving the site at N20.

§ The Contractor was reminded to collect the stagnant water for treatment prior to discharge at N4, S16, S8, S9, S11, S16, ventilation building, HMA of Portion Y, A2 bridge of N20 and inside the abandon wheel washing bay at N20.

§ The Contractor was reminded to use a red bucket to contain the water dripping from air-conditioner at HMA of Portion Y.

§ The Contractor was reminded to remove the empty chemical containers at S15.

§ The Contractor was reminded to provide a drip tray for the chemical containers to avoid land contamination at S8, S11, S15, scaffolding area of ventilation building and HMA of Portion Y.

§ The Contractor was reminded to clear oil stains at S11.

§ The Contractor was reminded to collect the waste properly at S15 and S25.

§ The Contractor was reminded to clean up a refuse skip frequently at S8.

§ The Contractor was reminded to remove the waste cement bags at S11.

§ The Contractor was reminded to remove the rubbish at N1, S7, S11, S15, S19, WA6, S25, A2 bridge of N20 and HMA of Portion Y.

§ The Contractor was reminded to clean up the general refuse / wood strips waste in the container at HMA of Portion Y.

§ The Contractor was reminded to clean up the used wooden panels and rubbish in the container at S11.

§ The Contractor was reminded to clean up the concrete waste at S19, N20 and HMA of Portion Y.

5.2 Recommendations

5.2.1 The impact monitoring programme for air quality, noise, water quality and dolphin ensured that any deterioration in environmental condition was readily detected and timely actions taken to rectify any non-compliance. Assessment and analysis of monitoring results collected demonstrated the environmental impacts of the contract. With implementation of the recommended environmental mitigation measures, the contract’s environmental impacts were considered environmentally acceptable. The weekly environmental site inspections ensured that all the environmental mitigation measures recommended were effectively implemented.

5.2.2 The recommended environmental mitigation measures, as included in the EM&A programme, effectively minimize the potential environmental impacts from the contract. Also, the EM&A programme effectively monitored the environmental impacts from the construction activities and ensure the proper implementation of mitigation measures. No particular recommendation was advised for the improvement of the programme.

5.3 Conclusions

5.3.1 The construction phase and EM&A programme of the Contract commenced on 17 October 2012. This is the thirteenth Quarterly EM&A Report which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 September 2015 to 30 November 2015.

Air Quality

5.3.2 There were no Action/Limit Level exceedances of 1-hour TSP and 24-hour TSP at AMS5 and AMS6 during the reporting period.

Noise

5.3.3 There were no Action/Limit Level exceedances for noise during daytime on normal weekdays of the reporting period.

Water Quality

5.3.4 For marine water quality monitoring, ten Action Level exceedances of suspended solid level were recorded during the reporting period. No Limit Level exceedance of suspended solid level was recorded. No Action Level/ Limit Level exceedance of turbidity level and dissolved oxygen level were recorded during the reporting period.

Dolphin

5.3.5 There were two Action Level exceedances of dolphin monitoring for the quarterly monitoring data (September – November 2015).

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

5.3.7 Although dolphins rarely occurred in the area of HKLR03 construction in the past and during the baseline monitoring period, it is apparent that dolphin usage has been significantly reduced in NEL since 2012, and many individuals have shifted away from the important habitat around the Brothers Islands.

5.3.8 It is critical to monitor the dolphin usage in North Lantau region in the upcoming quarters, to determine whether the dolphins are continuously affected by the various construction activities in relation to the HZMB-related works, and whether suitable mitigation measure can be applied to revert the situation.

Mudflat -Sedimentation Rate

5.3.9 This measurement result was generally and relatively higher than the baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.

Mudflat - Ecology

5.3.10 The September 2015 survey was the twelfth survey of the EM&A programme during the construction period. Based on the results, impacts of the HKLR project could not be detected on horseshoe crabs and intertidal soft shore community. Based on the results, there was recolonization of both seagrass species Halophila ovalis and Zostera japonica in ST. the seagrass patches were believed in recovery. Hence the negative impact of HKLR project on the seagrass was not significant.

Environmental Site Inspection and Audit

5.3.11 Environmental site inspection was carried out on 2, 9, 16, 25 and 30 September 2015, 7, 14, 22 and 30 October 2015 and 4, 11, 18 and 27 November 2015. Recommendations on remedial actions were given to the Contractors for the deficiencies identified during the site inspections.

Monitoring Activity		Monitoring Date
Monitoring Activity		September 2015	October 2015	November 2015
Air Quality	1-hr TSP	2, 8, 14, 18, 24 and 30	6, 12, 16, 22 and 27	2, 6, 12, 18, 24 and 30
Air Quality	24-hr TSP	1, 7, 11, 17, 23 and 29	AMS5: 5, 9, 15, 20, 26 and 30 AMS6: 5, 9, 15, 20 and 26	AMS5: 5, 11, 17, 23 and 27 AMS6: 5, 11, 17 and 27
Noise		4, 8, 14, 24 and 30	6, 12, 22 and 27	2, 12, 18, 24 and 30
Water Quality		2, 4, 7, 9, 11, 14, 16, 18, 21, 23, 25, 28 and 30	2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 26, 28 and 30	2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25, 27 and 30
Chinese White Dolphin		2, 11, 17 and 29	6, 13, 19 and 26	2, 6, 10 and 16
Mudflat Monitoring (Ecology)		5, 6, 10, 12 and 13	-	-
Mudflat Monitoring (Sedimentation rate)		10	-	-
Site Inspection		2, 9, 16, 25 and 30	7, 14, 22 and 30	4, 11, 18 and 27

Description of Activities	Site Area
Dismantling/trimming of temporary 40mm stone platform for construction of seawall	Portion X
Filling works behind stone platform	Portion X
Construction of seawall	Portion X
Loading and unloading of filling materials	Portion X
Band drains installation	Portion X
Excavation and lateral support works for Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Socket H-Piling work for Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Laying blinding layer for tunnel box structure at Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Construction of Sheet Pile at Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Construction of tunnel box structure at Scenic Hill Tunnel (Cut & Cover Tunnel)	Portion X
Pipe piling works for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)	Portion X
Excavation for HKBCF to Airport Tunnel	Portion X
Sheet Piling Works for HKBCF to Airport Tunnel East (Cut & Cover Tunnel)	Portion X
Socket H-Piling Works for HKBCF to Airport Tunnel East (Cut &Cover Tunnel)	Portion X
Excavation for Scenic Hill Tunnel	West Portal
Ventilation building foundation and superstructure works	West Portal
Superstructure works for Scenic Hill Tunnel West Portal Ventilation building	West Portal
Pipe piling works for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)	Airport Road
Works for diversion of Airport Road	Airport Road
Utilities detection	Airport Road/ Airport Express Line/ East Coast Road
Establishment of Site Access	Airport Road/ Airport Express Line/ East Coast Road
Canopy pipe drilling underneath Airport Express Line	Airport Express Line
Excavation and lateral support works at shaft 3 extension north shaft & south shaft	Kwo Lo Wan Road
Excavation and Lateral Support Works for HKBCF to Airport Tunnel West (Cut & Cover Tunnel)	Airport Road
Utility culvert excavation	Portion Y
Foundation works, sub-structure works and superstructure works for Highway Operation and Maintenance Area Building	Portion Y

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)	10	0
	Turbidity level	0	0
	Dissolved oxygen level (DO)	0	0
Dolphin Monitoring	Quarterly Analysis (Sep to Nov 2015)	2	0

1 Introduction

1.1.5 This is the thirteenth Quarterly Environmental Monitoring and Audit (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 September 2015 to 30 November 2015.

1.2.1 The project organization structure and lines of communication with respect to the on-site environmental management structure with the key personnel contact names and numbers are shown in Appendix A.

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 Period

1.4.1 A summary of the construction activities undertaken during this reporting period is shown in Table 1.1. The Works areas of the Contract are showed in Appendix C.

2 EM&A Requirement

2.1 Summary of EM&A Requirements

2.1.1 The EM&A programme requires environmental monitoring of air quality, noise, water quality, dolphin monitoring and mudflat monitoring as specified in the approved EM&A Manual.

2.1.2 A summary of Impact EM&A requirements is presented in Table 2.1. The locations of air quality, noise and water quality monitoring stations are shown as in Figure 2.1. The transect line layout in Northwest and Northeast Lantau Survey Areas is presented in Figure 2.2.

2.2.1 Table 2.2 presents the Action and Limit Levels for the 1-hour TSP, 24-hour TSP and noise level.

2.2.2 The Action and Limit Levels for water quality monitoring are given as in Table 2.3.

2.2.3 The Action and Limit Levels for dolphin monitoring are shown in Tables 2.4 and 2.5.

2.3 Event Action Plans

2.3.1 The Event Actions Plans for air quality, noise, water quality and dolphin monitoring are annexed in Appendix D.

2.4 Mitigation Measures

2.4.1 Environmental mitigation measures for the contract were recommended in the approved EIA Report. Appendix E lists the recommended mitigation measures and the implementation status.

3 Environmental Monitoring and Audit

3.1 Implementation of Environmental Measures

3.1.1 In response to the site audit findings, the Contractor have rectified all observations identified in environmental site inspections undertaken during the reporting period. Details of site audit findings and the corrective actions during the reporting period are presented in Appendix F.

3.1.2 A summary of the Implementation Schedule of Environmental Mitigation Measures (EMIS) is presented in Appendix E.

3.1.3 Regular marine travel route for marine vessels were implemented properly in accordance to the submitted plan and relevant records were kept properly.

3.1.4 Dolphin Watching Plan was implemented during the reporting period. No dolphins inside the silt curtain were observed. The relevant records were kept properly.

3.2.1 The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Tables 3.1 and 3.2 respectively. Detailed impact air quality monitoring results and relevant graphical plots are presented in Appendix G.

3.2.2 There were no Action and Limit Level exceedances of 1-hour TSP and 24-hour TSP were recorded at AMS5 and AMS6 during the reporting period.

3.3 Noise Monitoring Results

3.3.1 The monitoring results for construction noise are summarized in Table 3.3 and the monitoring results and relevant graphical plots for this reporting period are provided in Appendix H.

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

3.3.3 Major noise sources during the noise monitoring included construction activities of the Contract and nearby traffic noise and insect noise.

3.4.1 Impact water quality monitoring was conducted at all designated monitoring stations during the reporting period. Impact water quality monitoring results and relevant graphical plots are provided in Appendix I.

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

Data Analysis

Summary of Survey Effort and Dolphin Sightings

3.5.9 During the period of September to November 2015, six sets of systematic line-transect vessel surveys were conducted to cover all transect lines in NWL and NEL survey areas twice per month.

3.5.11 The total survey effort conducted on primary lines 656.41 km, while the effort on secondary lines was 245.84 km. Survey effort conducted on both primary and secondary lines were considered as on-effort survey data. A summary table of the survey effort is shown in Annex I of Appendix J.

3.5.12 During the six sets of monitoring surveys in September-November 2015, a total of 18 groups of 95 Chinese White Dolphins were sighted. A summary table of the dolphin sightings is shown in Annex II of Appendix J.

Distribution

Encounter Rate

3.5.24 Even for the same autumn quarters, the dolphin encounter rates in NWL during autumn 2015 were much lower than the ones recorded in autumn 2013 and 2014 (Table 3.7).

3.5.31 To ensure the continuous usage of North Lantau waters by the dolphins, every possible measure should be implemented by the contractors and relevant authorities of HZMB-related works to minimize all disturbances to the dolphins.

Group Size

Habitat Use

Mother-calf Pairs

3.5.39 During the present quarterly period, two young calves (i.e. unspotted calf or unspotted juvenile) were spotted with their mothers near Lung Kwu Chau

Activities and Associations with Fishing Boats

3.5.41 Four of the 18 dolphin groups were engaged in feeding activities, while two other dolphin groups were engaged in socializing activities. None of the dolphin groups were engaged in traveling or milling/resting activity during the three-month study period.

3.5.44 When compared to the baseline period, distribution of various dolphin activities during the present impact phase monitoring period was drastically different with a much more restricted area of occurrences.

3.5.45 As consistently recorded in the past monitoring quarters, none of the 18 dolphin groups was found to be associated with operating fishing vessels in North Lantau waters during the present impact phase period.

Summary Photo-identification works

3.5.46 From September to November 2015, over 2,500 digital photographs of Chinese White Dolphins were taken during the impact phase monitoring surveys for the photo-identification work.

3.5.47 In total, 34 individuals sighted 65 times altogether were identified (see summary table in Annex III of Appendix J and photographs of identified individuals in Annex IV of Appendix J). All of these re-sightings were made in NWL.

3.5.48 The majority of identified individuals were sighted only once or twice during the three-month period, with the exception of two individuals (NL46 and NL210) being 3-4 times and another three individuals (NL48, NL202 and NL286) being sighted 5-6 times.

Individual range use

3.5.50 Ranging patterns of the 34 individuals identified during the three-month study period were determined by fixed kernel method, and are shown in Annex V of Appendix J.

Action Level / Limit Level Exceedance

3.5.60 It was concluded that the HZMB works is one of the contributing factors affecting the dolphins. It was also concluded the contribution of impacts due to the HZMB works as a whole (or individual marine contracts) cannot be quantified nor separate from the other stress factors.

3.5.61 It was reminded that the ETs shall keep reviewing the implementation status of the dolphin related mitigation measures and remind the contractor to ensure the relevant measures were fully implemented.

3.5.62 It was recommended that the marine works of HZMB projects should be completed as soon as possible so as to reduce the overall duration of impacts and allow the dolphins population to recover as early as possible.

3.5.63 It was also recommended that the marine works footprint (e.g., reduce the size of peripheral silt curtain) and vessels for the marine works should be reduced as much as possible, and vessels idling / mooring in other part of the North Lantau shall be avoided whenever possible.

3.5.65 There was a discussion on exploring possible further mitigation measures, for example, controlling the underwater noise. It was noted that the EIA reports for the projects suggested several mitigation measures, all of which have been implemented.

3.6 Mudflat Monitoring Results

Sedimentation Rate Monitoring

3.6.2 This measurement result was generally and relatively higher than the baseline measurement at S1, S2, S3 and S4. The mudflat level is continuously increased.

Water Quality Monitoring

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

3.6.4 Impact water quality monitoring in San Tau (monitoring station SR3) was conducted in September 2015. The monitoring parameters included dissolved oxygen (DO), turbidity and suspended solids (SS).

3.6.5 The Impact monitoring result for SR3 were extracted and summarised below:

Mudflat Ecology Monitoring

Sampling Zone

Horseshoe Crabs

Seagrass Beds

Intertidal Soft Shore Communities

3.6.11 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.

3.6.12 The taxonomic classification was conducted in accordance to the following references: Polychaetes: Fauchald (1977), Yang and Sun (1988); Arthropods: Dai and Yang (1991), Dong (1991); Mollusks: Chan and Caley (2003), Qi (2004).

Data Analysis

3.6.13 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,

Mudflat Ecology Monitoring Results and Conclusion

Horseshoe Crabs