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 |
||||
|
December 2017 |
AMS1 |
112 |
21 – 234 |
381 |
500 |
|
AMS4 |
98 |
36 – 165 |
352 |
||
|
January 2018 |
AMS1 |
127 |
22 – 446 |
381 |
|
|
AMS4 |
146 |
24 – 322 |
352 |
||
|
February 2018 |
AMS1 |
63 |
27 – 114 |
381 |
|
|
AMS4 |
92 |
50 – 179 |
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 |
||||
|
December 2017 |
AMS1 |
79 |
62 – 93 |
170 |
260 |
|
AMS4 |
74 |
53 – 120 |
171 |
||
|
January 2018 |
AMS1 |
57 |
38 – 82 |
170 |
|
|
AMS4 |
45 |
28 – 63 |
171 |
||
|
February 2018 |
AMS1 |
47 |
23 – 66 |
170 |
|
|
AMS4 |
53 |
36 – 65 |
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 |
|||
|
December 2017 |
NMS1 |
69 |
64 – 72 |
75 dB(A) |
|
NMS4 |
57 |
54 – 60 |
||
|
January 2018 |
NMS1 |
71 |
65 – 73 |
|
|
NMS4 |
59 |
55 – 62 |
||
|
February 2018 |
NMS1 |
70 |
62 – 72 |
|
|
NMS4 |
61 |
57 – 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 December 2017 to
February 2018, 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 200.87 km of survey effort was collected, with 88.8% of the total survey effort being conducted
under favourable weather conditions (i.e. Beaufort
Sea State 3 or below with good visibility). The total survey effort conducted on primary lines was 131.58 km, while the effort on secondary lines was 69.29 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 December 2017 to February
2018, a total of 12 groups of 43 Chinese White
Dolphins were sighted. All twelve dolphin sightings were made during on-effort search. Seven on-effort
sightings were made on primary lines, while the
other five 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 December 2017 to February 2018 is shown in Figure 1 of Appendix F. The dolphin groups were scattered evenly
across the WL survey area with no particular concentration (Figure 1 of Appendix F).
However, they appeared to avoid the waters near Tai O Peninsula, as well
as the offshore waters between Kai Kung Shan and Peaked Hill, where dolphins
were used to be sighted frequently in the past (Figure 1 of Appendix F).
4.12
Sighting distribution of dolphins in the present
quarter was very 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
around Tai O Peninsula and Kai Kung Shan, as well as the offshore waters along
the western territorial boundary during the present impact phase period (Figure 1 of Appendix F).
4.13
One of the 12 dolphin groups was sighted near the
HKLR09 alignment in WL survey area during the present quarter (Figure 2 of Appendix F).
4.14
Unlike the previous monitoring quarters, dolphins
appeared to occur more often near the HKLR09 alignment during the present
quarterly period. As the disturbance
arisen from the HKLR09 construction activities on the dolphins have been
completed, dolphins may start to utilize the waters in the vicinity of the
bridge alignment. However, it is
premature to conclude that the potential obstruction from the permanent
physical structure of the bridge piers does not occur any more, and this critical
issue 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 winter quarters of 2014-17 were compared with the one in 2017-18. It is apparent that dolphin occurrence
during the winter period of 2017-18 was lower than the previous three winter
periods, especially around the Tai O Peninsula and between Peaked Hill and Fan
Lau (Figure 3 of Appendix F).
Encounter
rate
4.16
During the present three-month impact phase
monitoring period (December 2017 to February 2018), 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 (December 2017
to February 2018)
|
Survey Area |
Dolphin Monitoring |
Encounter rate (STG) |
Encounter rate (ANI) |
|
Primary Lines Only |
Primary Lines Only |
||
|
West Lantau |
0.0 |
0.0 |
|
|
Set 2 (December 21st) |
5.6 |
39.2 |
|
|
Set 3 (January 3rd) |
21.1 |
63.3 |
|
|
Set 4 (January 23rd) |
4.2 |
4.2 |
|
|
Set 5 (February 8th) |
6.4 |
19.2 |
|
|
Set 6 (February 23rd) |
0.0 |
0.0 |
Table 4.7 Comparison of average dolphin
encounter rates from impact monitoring period (December 2017 to February 2018)
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) |
||
|
December 2017 – February 2018 |
September- November 2011 |
December 2017 – February 2018 |
September- November 2011 |
|
|
West Lantau |
6.22
± 7.79 |
16.43±
7.70 |
20.99
± 25.64 |
60.50±
38.47 |
4.17
Notably, the encounter rates of dolphin
sightings (ER(STG)) and encounter rates of dolphins (ER(ANI)) in the present
quarter (December 2017 to February 2018) dropped to the lowest among all
quarterly periods during the construction phase, and were much lower than the
baseline level (Table 4.7). Moreover, the Limit Level under the
Event and Action Plan was triggered for the first time, after the Action Levels
were triggered in the previous three consecutive quarters. 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 2017.
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. the 19th
quarter of the impact phase), the p-value for the differences in average
dolphin encounter rates of STG and ANI were 0.045 and 0.063 respectively. Therefore, if the alpha value is set at
0.05, significant difference was detected between the baseline period and the
present quarter in encounter rate of STG, but not in encounter rate of ANI.
4.19
Another
comparison was made between the baseline period and the 19 cumulative quarters
in the impact phase, and the p-value for the differences in average dolphin
encounter rates of STG and ANI were 0.439 and 0.555 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 to 14 individuals per group in WL
survey area during December 2017 to February 2018. 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 (December 2017 to February 2018) and
baseline monitoring period (September-November 2011)
|
|
Average Dolphin Group
Size |
|
|
December 2017 – February 2018 |
September – November 2011 |
|
|
West Lantau |
3.58 ± 3.75 (n = 12) |
3.63 ± 2.97 (n = 46) |
4.21
The
average dolphin group size in the WL region during the
present quarter was slightly lower than the one recorded in the three-month
baseline period (Table 4.8). Among the 12 groups, nine of them were
composed of only 1-3 dolphins, while there were only two groups in moderate
size with five and seven animals respectively, and one large group with 14 animals.
4.22
Distribution
of dolphins with larger group sizes (with five or more animals per group) during
December 2017 to February 2018 is shown in Figure
4 of Appendix F. The three
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, and were scattered between the waters to the west of Kai
Kung Shan and Fan Lau (Figure 4 of
Appendix F).
Habitat
use
4.23
From December 2017 to February 2018, the few grids
that recorded higher densities of dolphins were located near Kai Kung Shan, Fan
Lau, and between Peaked Hill and Fan Lau (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 overall dolphin occurrence was drastically lower during the present impact
phase monitoring period. Only a few
grids recorded high densities of dolphins near Kai Kung Shan and Fan Lau in the
present quarter, which was very different from the dolphin habitat use during
the baseline period when many high density grids were evenly distributed from
Tai O Peninsula to Fan Lau (Figure 6 of
Appendix F).
Mother-calf
pairs
4.25
During the three-month impact phase monitoring period, only
two young calves (one unspotted calf and one unspotted juvenile) were sighted in WL survey area from the same dolphin group. These young
calves comprised 4.7% of all animals sighted, which was noticeably lower than the percentage recorded during the baseline
monitoring period (6.6%). The occurrence of these young
calves from the same sighting occurred between Peaked Hill and Fan Lau, and such
occurrence was considerably different from the baseline period when calf
occurrence was much more frequent and concentrated in the northern portion of
WL waters near Tai O Peninsula (Figure 7
of Appendix F).
Activities
and associations with fishing boats
4.26
During the three-month impact monitoring period, none
of the dolphin groups were engaged in feeding, socializing, traveling or
resting/milling activity. Moreover,
none of the 12 dolphin groups was associated with any operating fishing vessel.
Summary
of photo-identification works
4.27
From December 2017 to February 2018, over 1,500
digital photographs of Chinese White Dolphins were taken during the impact
phase monitoring surveys for the photo-identification work.
4.28
In total, 26 individuals sighted 37 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). Most of these individuals were re-sighted
only once during the three-month period, with the exception of seven
individuals (CH108, NL206, SL40, WL42, WL123, WL180 and WL215) being re-sighted
twice, and two individuals being re-sighted thrice (CH38 and NL212) (Appendix III of Appendix F).
4.29
Only one of these individuals, WL273, was also
re-sighted in North Lantau waters during a HKLR03 monitoring survey in the same
three-month period, showing some level of individual movement across the HKLR09
bridge alignment.
4.30
Notably, unlike the previous quarters, none of
the individuals identified in WL waters were consistently sighted in North
Lantau waters in the past.
Individual
range use
4.31
Ranging patterns of the 26 individuals identified
during the three-month study period were determined by fixed kernel method, as
shown in Appendix V of Appendix F.
4.32
As in previous monitoring quarters, the majority
of 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). However, one individual,
WL273, apparently has extended its range use from WL waters to NWL waters (Appendix V of Appendix F).
Conclusion
4.33
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.
4.34
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.
4.35
There was an Limit Level
exceedance of dolphin monitoring for the quarterly monitoring data (between December
2017 to February 2018). According to the investigation report (Appendix K), the exceedance is
considered not due to the Contract.
4.36
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.
4.37
The amount of wastes generated by the activities
of the Contract during the reporting month is shown in Appendix J.