4.1
The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Table 4.1 and 4.2 respectively. Graphical presentations of 1-hour and 24-hour TSP monitoring results
are shown in Appendices B and C respectively.
Table 4.1 Summary Table of 1-hour TSP Monitoring
Results during the Reporting Period
Month |
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
Average |
Range |
||||
September 2017 |
AMS1 |
25 |
0 – 73 |
381 |
500 |
AMS4 |
24 |
0 – 86 |
352 |
||
October 2017 |
AMS1 |
52 |
12 – 92 |
381 |
|
AMS4 |
56 |
7 – 119 |
352 |
||
November 2017 |
AMS1 |
108 |
50 – 182 |
381 |
|
AMS4 |
94 |
24 – 176 |
352 |
Table 4.2 Summary
Table of 24-hour TSP Monitoring Results during the Reporting Period
Month |
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
Average |
Range |
||||
September 2017 |
AMS1 |
37 |
18 – 57 |
170 |
260 |
AMS4 |
52 |
25 – 79 |
171 |
||
October 2017 |
AMS1 |
55 |
21 – 83 |
170 |
|
AMS4 |
61 |
25 – 72 |
171 |
||
November 2017 |
AMS1 |
66 |
33 – 83 |
170 |
|
AMS4 |
57 |
26 – 79 |
171 |
4.2
According to our field observations, the major dust source identified at
the designated air quality monitoring stations in the reporting period are as
follows:
Table
4.3 Observation at Dust
Monitoring Stations
Monitoring Station |
Major Dust Source |
AMS1 |
Exhaust from marine traffic |
AMS4 |
N/A |
4.3
The wind data monitoring results were attached in the Monthly EM&A
Reports
4.4
The noise monitoring results are summarized in Table 4.4. Graphical presentations of noise
monitoring are shown in Appendix D.
Table 4.4 Summary
Table of Noise
Monitoring Results during the Reporting Period
Month |
Monitoring Station |
Noise Level, Leq
(30min) dB(A) |
Limit
Level |
|
Average |
Range |
|||
September 2017 |
NMS1 |
66 |
54 – 70 |
75 dB(A) |
NMS4 |
57 |
51 – 59 |
||
October 2017 |
NMS1 |
68 |
61 – 72 |
|
NMS4 |
59 |
51 – 64 |
||
November 2017 |
NMS1 |
71 |
64 – 73 |
|
NMS4 |
60 |
49 – 64 |
Remark: +3dB(A) Façade correction included
4.5
According to our field observations, the major noise source identified
at the designated noise monitoring stations in the reporting period are as
follows:
Table 4.5 Observation
at Noise
Monitoring Stations
Monitoring Station |
Major Noise Source |
NMS1 |
Air
traffic & marine traffic noise |
NMS4 |
Air
traffic & marine traffic noise |
4.6
The graphical presentation of water quality at the monitoring stations
is shown in Appendix E.
4.7
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.
Summary
of survey effort and dolphin sightings
4.8
During the period of September
to November 2017, six sets of systematic line-transect vessel surveys were conducted to
cover all transect lines in WL survey area twice per month.
4.9
From these surveys, a total of 201.17 km of survey effort was collected, with 80.2% of the total survey effort being conducted
under favorable weather conditions (i.e. Beaufort Sea State 3 or below with
good visibility). The total survey effort conducted on primary
lines was 132.76 km, while the effort
on secondary lines was 68.41 km. Survey effort conducted on primary and
secondary lines were both considered as on-effort survey data. Summary table of the survey effort is shown
in Appendix I of Appendix F.
4.10
During the six sets of monitoring surveys in September
to November 2017, a total of 20 groups of 71 Chinese White Dolphins were sighted. All 18 dolphin
sightings were made during on-effort search. Eleven on-effort sightings were made on primary lines, while the other seven on-effort sightings were made on secondary lines. Summary table of the dolphin sightings is
shown in Appendix II of Appendix F.
Distribution
4.11
Distribution of dolphin sightings made during HKLR09
monitoring surveys from September to November 2017 is shown in Figure 1 of Appendix F. The dolphin groups were mainly clustered
near Tai O Peninsula and to the west of Kai Kung Shan, with some other
sightings also made between the two areas (Figure
1 of Appendix F). Moreover, two
sightings were made at the northern end of the WL survey area, or a few
kilometers to the west of the airport platform (Figure 1 of Appendix F).
4.12
Sighting distribution of dolphins in the present
quarter was quite different from the one during the baseline period in September
to November 2011. When compared to
the baseline period, dolphins occurred much less frequently in the waters
between Tai O Peninsula and Kai Kung Shan, as well as the southern end near Fan
Lau during the present impact phase period (Figure 1 of Appendix F).
4.13
None of the 20 dolphin groups was sighted near
the HKLR09 alignment in WL survey area during the present quarter (Figure 2 of Appendix F).
4.14
Similar to the previous monitoring quarters, dolphins
have somewhat avoided the HKLR09 alignment during the present quarterly
period. Even though the disturbance
arisen from the HKLR09 construction activities on the dolphins have been
completed, dolphins consistently did not utilize the waters in the vicinity of
the bridge alignment. This could be
related to the potential obstruction from the permanent physical structure of
the bridge piers, which should be continuously monitored in the upcoming
quarters through boat surveys and land-based theodolite tracking surveys.
4.15
Distribution patterns of dolphin sightings in the
past three autumn quarters of 2014-16 were also compared with the one in
2017. Such distribution patterns
were similar across the four-year period, and the only obvious difference was
their infrequent occurrence in the offshore waters as well as the southern end
of the survey area in 2017 when compared to the previous years (Figure 3 of Appendix F).
Encounter
rate
4.16
During the present three-month impact phase
monitoring period (September to November 2017), 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) from West Lantau survey area are shown in Table 4.6. The average encounter rates
deduced from the six sets of surveys from the present quarter were also
compared with the ones deduced from the baseline monitoring period (September –
November 2011) (Table 4.7).
Table 4.6 Dolphin encounter rates (sightings
per 100 km of survey effort) during the impact monitoring period (September to
November 2017)
Survey Area |
Dolphin Monitoring |
Encounter rate (STG) |
Encounter rate (ANI) |
Primary Lines Only |
Primary Lines Only |
||
West Lantau |
4.4 |
26.6 |
|
Set 2 (September 13th) |
18.4 |
59.9 |
|
Set 3 (October 10th) |
6.3 |
12.7 |
|
Set 4 (October 24th) |
4.5 |
9.0 |
|
Set 5 (November 9th) |
19.4 |
38.7 |
|
Set 6 (November 22nd) |
0.0 |
0.0 |
Table 4.7 Comparison of average dolphin
encounter rates from impact monitoring period (September to November 2017) and baseline monitoring period
(September-November 2011)
|
(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
2017 |
September- November 2011 |
September –November
2017 |
September- November 2011 |
|
West Lantau |
8.84
± 8.07 |
16.43±
7.70 |
24.47
± 22.09 |
60.50±
38.47 |
4.17
Notably, after dropping to the lowest in the second
quarterly period in 2017 since the impact phase monitoring commenced in spring
2013, the encounter rates of dolphin sightings (ER(STG))
and encounter rates of dolphins (ER(ANI)) for the past two quarters of 2017 remained
at a relatively low level, and were much lower than the baseline level (Table 4 of Appendix F). Moreover, the
Action Level under the Event and Action Plan was triggered for the Third
consecutive quarter. It is critical
to continuously monitor such temporal trend, as the dolphin usage continued to
diminish in recent quarters even when the HKLR09 marine construction works have
already been completed in 2016.
4.18
A one-way ANOVA was conducted to examine whether
there were any significant differences in the average encounter rates between
the baseline and impact monitoring periods. For the comparison between the baseline
period and the present quarter (i.e. eighteenth quarter of the impact phase),
the p-value for the differences in average dolphin encounter rates of STG and
ANI were 0.080 and 0.074 respectively.
Therefore, if the alpha value is set at 0.05, significant difference in both encounter rates
of STG and ANI was not detected between the baseline period and the present
quarter.
4.19
Another comparison was made between the baseline
period and the 18 cumulative quarters in the impact phase, and the p-value for
the differences in average dolphin encounter rates of STG and ANI were 0.493
and 0.612 respectively. As a
result, no significant difference was found in the dolphin encounter rates
between the baseline period and the cumulative quarters in the impact phase.
Group
size
4.20
Group size of Chinese White Dolphins ranged from 1-16
individuals per group in WL survey area during September to November 2017. The average dolphin group size for the
three-month period was compared with the one deduced from the baseline period
in September to November 2011, as shown in Table
4.8.
Table 4.8 Comparison of average dolphin
group sizes from impact monitoring period (September-November 2017) and baseline
monitoring period (September-November 2011)
|
Average Dolphin Group
Size |
|
September – November 2017 |
September – November 2011 |
|
West Lantau |
3.55 ± 3.43 (n = 20) |
3.63 ± 2.97 (n = 46) |
4.21
The average dolphin group size in the WL region
during the present quarter was only slightly lower than the one
recorded in the three-month baseline period (Table 4.8). Among the 20 groups, 14 of them were composed
of only 1-4 dolphins, while
there were only five groups in moderate size with 5-9 animals per group, and
one large group with 16 animals.
4.22
Distribution of dolphins with larger group sizes
(with five or more animals per group) during September to November 2017 is
shown in Figure 4 of Appendix F. These larger dolphin groups in the
present impact phase period was distributed quite differently from the baseline
period, as there was no particular concentration of these sightings which were
scattered from the west of the airport platform to the offshore waters to the
west of Kai Kung Shan (Figure 4 of Appendix F).
Habitat
use
4.23
From September to November 2017, the grids that
recorded higher densities of dolphins were mostly found near Tai O Peninsula,
Kai Kung Shan and Peaked Hill (Figures
5a & 5b of Appendix F). However, it should be cautioned that the amount
of survey effort collected in each grid during the three-month
period was fairly low (six 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 will be presented when more survey effort for each grid
will be collected throughout the impact phase monitoring programme.
4.24
When compared with the habitat use pattern
recorded during the baseline period in September-November 2011, it appears that
the high density grids of dolphins were much less evenly distributed in the
present impact phase monitoring period, and the overall dolphin densities were
much lower in certain areas such as the waters near Kai Kung Shan and Fan Lau (Figure 6 of Appendix F).
Mother-calf
pairs
4.25
During the three-month impact phase monitoring period, four
young calves (all were unspotted juvenile) were
sighted in WL survey area. These young
calves comprised 5.6% of all animals sighted, which was lower
than the percentage recorded during the baseline
monitoring period (6.6%). The occurrence
of these young calves was scattered from the north of Tai O Peninsula to the
west of Peaked Hill, with no particular concentration. Such occurrence was very different from
the baseline period when calf occurrence was more frequent and concentrated in
the northern portion of WL waters (Figure
7 of Appendix F).
Activities
and associations with fishing boats
4.26
During the three-month impact monitoring period,
four dolphin groups were engaged in socializing activities near Tai O Peninsula
and to the offshore waters west of Peaked Hill (Figure 8 of Appendix F), comprising 20% of the total number of dolphin sightings. On the other hand, none of
the dolphin groups was engaged in feeding, traveling or resting/milling
activity during the present quarter (Figure
8 of Appendix F).
4.27
Distribution of different activities during the
present impact phase monitoring period was quite different from the one during
the baseline period, when the main concentration of the feeding and socializing
activities occurred at the central portion of the survey area between Tai O
Peninsula and Peaked Hill (Figure 8 of
Appendix F).
4.28
During the three-month monitoring period, none
of the 20 dolphin groups was associated with any operating fishing vessel.
Summary
of photo-identification works
4.29
From September to November 2017, over 2,500
digital photographs of Chinese White Dolphins were taken during the impact
phase monitoring surveys for the photo-identification work.
4.30
In total, 40 individuals sighted 44 times
altogether were identified (see the summary table in Appendix III of Appendix F and photographs of identified
individuals in Appendix IV of Appendix F). Almost all of them were re-sighted only
once during the three-month period, with the exception of four individuals
(NL301, NL317, WL145 and WL241) being re-sighted twice (Appendix III of Appendix F).
4.31
Notably, eight of these individuals (i.e. CH34,
NL12, NL49, NL182, NL210, NL317, WL05 and WL145) were also re-sighted in North
Lantau waters during the HKLR03 and HKBCF monitoring surveys in the same
three-month period, showing some level of individual movements across the
HKLR09 bridge alignment.
4.32
As in previous quarters, several individuals that
were consistently sighted in North Lantau waters in the past were identified in
West Lantau waters (e.g. CH34, NL12, NL49, NL182). It is likely that some of these
identified dolphins have either shifted or expanded their range use into West
Lantau due to the increased disturbance from construction works in North Lantau
region, including both the HZMB project and the third runway expansion project
Individual
range use
4.33
Ranging patterns of the 40 individuals identified
during the three-month study period were determined by fixed kernel method, as
shown in Appendix V of Appendix F.
4.34
As in previous monitoring quarters, several individual
dolphins (e.g. NL12, NL80, NL210, NL301) that
primarily centered their range use in North Lantau in the past were found
extending their ranges to West Lantau waters, with some shifts and expansions
of their range use away from North Lantau waters (Appendix V of Appendix F).
4.35
On the contrary, the majority of the identified
individuals that primarily centered their range use in West Lantau were still
sighted within their normal ranges during the present quarterly period (Appendix V of Appendix F).
Conclusion
4.36
During the present quarter of dolphin monitoring,
no adverse impact from the activities of the HKLR09 construction project on
Chinese White Dolphins was noticeable from general observations.
4.37
Nevertheless, the dolphin usage in WL region
should be continuously monitored, to further examine whether it has been significantly
affected by the on-going construction activities in relation to the HZMB works.
4.38
There was an Action Level exceedance of dolphin
monitoring for the quarterly monitoring data (between September
to November 2017). According to the investigation report (Appendix K), the exceedance is considered not due to the Contract.
4.39
The Contractor was advised to minimize the wastes
generated through the recycling or reusing. All mitigation measures stipulated
in approved waste management plan shall be fully implemented.
4.40
The amount of wastes generated by the activities
of the Contract during the reporting month is shown in Appendix J.