The Project “Landslide Preventive Works at Po Shan, Mid-levels – Design
and Construction (Natural Terrain Risk Mitigation Works)” (hereafter called
“the Project”) includes the installation of about 700 numbers of soil nails and
about 60 numbers of raking drains on the natural terrain within the concerned
area.
China State – China Railway Joint Venture (CCJV) was commissioned as the Contractor
of the Project. ENSR Asia (HK) Ltd., which was integrated into AECOM Asia
Company Limited as of 1 May 2009, was employed by CCJV as the Environmental
Team to carry out the EM&A programme.
The impact environmental monitoring and audit for the Project includes
the air quality, noise, ecology, landscape and visual monitoring. The
construction of the Project and the EM&A programme commenced on 1 April
2008.
This report documented the findings of EM&A works conducted in the
period between 1 and 30 June 2009. As informed by the Contractor, construction
activities in the reporting period were:
-
Soil nailing
works at Portion B2;
-
Soil nail head construction at
Portion C;
-
Rock slope stabilization works
at Portion D; and
-
Slope reinstatement works at
Portion A1, A2, B1 and C.
Breaches of Action and Limit
Levels
There was no action / limit level exceedance recorded for 1-hour and
24-hour TSP monitoring.
In the reporting month, all noise level recorded complied with the limit
level.
Complaint, Notification of
Summons and Successful Prosecution
There was no complaint, notification of summons and successful
prosecution received in the reporting month.
Reporting Change
There was no reporting change required in the reporting month.
Future Key Issues
The weather in the forthcoming month is expected to be wet and windy.
The Contractor should provide preventive measures to prevent any muddy runoff,
such as proper collection and treatment of the runoff and provide a functional
temporary drainage system in site.
It is also recommended to implement all necessary preventive measures to
avoid oil leakage on ground / soil, such as provision of drip trays for all oil
drums / chemical containers. In the event of oil leakage, the Contractor should
properly remove the contaminated soil and dispose of as chemical waste.
Construction waste and general refuse should be properly collected and disposed
of.
Background
1.1
The project site is located at the mostly
undeveloped hillside above the residential development at Po Shan Road and adjacent to the trimmed
back slope on the site of the catastrophic 1972 Po Shan Road failure. Previous
studies had been carried out and results indicated that the natural hillside
above Po Shan Road
is affected by high groundwater level and unfavourable geology. Sub-surface
drainage measures by means of sub-horizontal drains had been installed in
1984-85. These measures have been successful in lowering the main ground water
table, thus improving the stability of the slopes such that large-scale failure
have not occurred in the last twenty years.
1.2
The objective of the Project “Landslide Preventive
Works at Po Shan, Mid-levels – Design and Construction (Natural Terrain Risk
Mitigation Works)” under Contract CE 28/2004 (GE) is to carry out detailed
design and supervision of landslide preventive works on local repair of the
hillside to minimize slope deterioration and shallow instability.
1.3
The proposed landslide preventive works would be
constructed to protect the existing residential developments at the toe of the
project site.
1.4
The scope of works of this Project includes the
installation about 700 numbers of soil nails and about 60 numbers of raking
drains on the natural terrain within the concerned area. The length of the soil
nails is about 20m
with a spacing of 2m
horizontally and 3m
vertically; the length of raking drains is about 10m with a spacing of 5m horizontally and 15m vertically.
1.5
The Project is anticipated to complete in 10 months
after the commencement of construction.
1.6
According to the Environmental Permit
(EP-235/2005/B) and the EM&A Manual of the Project, there is a need of an
EM&A programme including air quality, noise, ecology, and landscape and
visual monitoring.
1.7
ENSR Asia (HK) Ltd., which was integrated into AECOM Asia Company Limited as of 1 May 2009, was employed by
the Contractor, China
State – China Railway
Joint Venture, as the Environmental Team (ET) to undertake the Environmental
Monitoring and Audit (EM&A) works for the Project. In accordance with the
EM&A Manual of the Project, environmental monitoring of air quality, noise,
ecology, landscape and visual and environmental site inspections would be
required for this Project.
Scope of Report
1.8
This is the fifteenth monthly Environmental
Monitoring and Audit (EM&A) Report under the Contract CE 28/2004 (GE) –
Landslide Preventive Works at Po
Shan Road, Mid-Levels – Design and Construction
(Natural Terrain Risk Mitigation Works). This report presented a summary of the
environmental monitoring and audit works, list of activities, and mitigation
measures proposed by the ET for the Project in June 2009.
Project Organization
1.9
The project organization is
shown in Appendix A. The key personnel contact names and numbers are summarized
in Table 1.1
.
Table 1.1 Contact Information
of Key Personnel
|
Party
|
Position
|
Name
|
Telephone
|
Fax
|
|
CEDD
|
Senior Engineer
|
H. W. Sun
|
2762 5375
|
2714 0247
|
|
ER (MGS)
|
Resident Engineer
|
Freddie Chan
|
3188 0400
|
3188 0775
|
|
Assistant Resident Engineer
|
S. F. Chau
|
3188 0400
|
3188 0775
|
|
IEC
(ENVIRON)
|
Independent
Environmental Checker
|
David
Yeung
|
3743
0788
|
3548
6988
|
|
Contractor
(CCJV)
|
Project
Manager
|
C.
Y. Mak
|
3188
0538
|
3188
1710
|
|
Safety
and Environmental Officer
|
Brian
Yam
|
3188
0538
|
3188
1710
|
|
ET
(ENSR)
|
ET
Leader
|
Edith
Ng
|
3105
8525
|
2891
0305
|
Summary of Construction Works
1.10
The Contactor has carried
out major activities in the reporting month. Details of the works undertaken in
this reporting period are listed below:
-
Soil
nailing works at Portion B2;
-
Soil nail head construction at
Portion C;
-
Rock slope stabilization works
at Portion D; and
-
Slope reinstatement works at
Portion A1, A2, B1 and C.
1.11
The general layout plan of
the Project site showing the contract area is shown in Figure 1.1. The
construction programme is provided in Appendix B.
1.12
The mitigation measures
implementation schedule are presented in Appendix C.
Summary of EM&A Programme Requirements
1.13
The EM&A programme
required environmental monitoring for air quality, noise, ecology and landscape
and visual and environmental site inspections for air quality, noise, ecology,
landscape and visual and waste management. The EM&A requirements for each
parameter described in the following sections include:
-
All monitoring parameters;
-
Monitoring schedules for
the reporting month and forthcoming months;
-
Action and Limit levels for
all environmental parameters;
-
Event / Action Plan;
-
Environmental mitigation
measures, as recommended in the Project EIA study final report; and
-
Environmental requirement
in contract documents.
Monitoring Requirements
2.1
In accordance with the EM&A Manual, 1-hour and
24-hour TSP levels at 2 air quality monitoring stations were established.
Impact 1-hour and 24-hour TSP monitoring was conducted for at least once every
7 days during the construction phase of the Project. The Action and Limit level
of the air quality monitoring is provided in Appendix D.
Monitoring Equipment
2.2
24-hour TSP air quality monitoring was performed
using High Volume Sampler (HVS) located at each designated monitoring station.
The HVS meets all the requirements of the EM&A Manual. Portable direct
reading dust meters were used to carry out the 1-hour TSP monitoring. Table 2.1
summarises the equipment used.
Table 2.1 Air Quality
Monitoring Equipment
|
Equipment
|
Model
|
|
High
Volume Sampler
|
GS 2310
Accu-vol system
|
|
Calibrator
|
GMW 25
|
|
1-hour
TSP Dust Meter
|
Laser
Dust Monitor – Model LD-3
|
Monitoring Parameters, Frequency and Duration
2.3
Table 2.2 summarizes the monitoring parameters,
frequency and duration of impact TSP monitoring.
Table 2.2 Air Quality
Monitoring Parameters, Frequency and Duration
|
Monitoring Station
|
Parameter
|
Frequency and Duration
|
|
CA1 & CA2
|
|
At least once every 7 days
|
|
1-hour TSP
|
At least 3 times every 7 days
|
Monitoring Locations
2.4
Both monitoring stations were set up at the
proposed locations in accordance with EM&A Manual. Table 2.3 describes
details of the two monitoring stations. The monitoring locations are shown in
Figure 2.1.
Table 2.3 Locations of Air
Quality Monitoring Stations
|
Monitoring Station
|
Identity / Description
|
|
CA1
|
Access
road to Po Shan Mansions
|
|
CA2
|
Podium
of Hamilton Court
|
Monitoring Methodology
24-hour TSP Monitoring
Installation
2.5
The HVS was installed in the vicinity of the air
sensitive receivers. The following
criteria were considered in the installation of the HVS.
·
A horizontal platform with appropriate support to
secure the sampler against gusty wind was provided.
·
The distance between the HVS and any obstacles,
such as buildings, was at least twice the height that the obstacle protrudes
above the HVS.
·
A minimum of 2 meters separation from walls,
parapets and penthouse was required for rooftop sampler.
·
No furnace or incinerator flues were nearby.
·
Airflow around the sampler was unrestricted.
·
Permission was obtained to set up the samplers and
to obtain access to the monitoring stations.
·
A secured supply of electricity is needed to
operate the samplers.
Preparation of Filter Papers
·
Glass fibre filters, G810 were labeled and sufficient filters that were
clean and without pinholes were selected.
·
All filters were equilibrated in the conditioning environment for 24
hours before weighing. The conditioning
environment temperature was around 25
°C and not variable by more than ±3 °C; the relative humidity (RH) was < 50% and not
variable by more than ±5%. A convenient
working RH was 40%.
·
ALS Technichem (HK) Pty Ltd. has comprehensive quality
assurance and quality control programmes.
Field Monitoring
·
The power supply was checked to ensure the HVS works properly.
·
The filter holder and the area surrounding the filter were cleaned.
·
The filter holder was removed by loosening the four bolts and a new
filter, with stamped number upward, on a supporting screen was aligned
carefully.
·
The filter was properly aligned on the screen so that the gasket formed an
airtight seal on the outer edges of the filter.
·
The swing bolts were fastened to hold the filter holder down to the
frame. The pressure applied should be
sufficient to avoid air leakage at the edges.
·
Then the shelter lid was closed and was secured with the aluminum strip.
·
The HVS was warmed-up for about 5 minutes to establish run-temperature
conditions.
·
A new flowrate record sheet was set into the flow recorder.
·
The range specified in the EM&A Manual was between 0.6-1.7 m3/min.
·
The programmable timer was set for a sampling period of 24 hrs +
1 hr, and the starting time, weather condition and the filter number were
recorded.
·
The initial elapsed time was recorded.
·
At the end of sampling, the sampled filter was removed carefully and
folded in half length so that only surfaces with collected particulate matter
were in contact.
·
It was then placed in a clean plastic envelope and sealed.
·
All monitoring information was recorded on a
standard data sheet.
·
Filters were sent to ALS Technichem (HK) Pty Ltd. for
analysis.
Maintenance and Calibration
·
The HVS and its accessories are maintained in good working condition,
such as replacing motor brushes routinely and checking electrical wiring to
ensure a continuous power supply.
·
HVSs are calibrated using GMW-25 Calibration Kit prior to the
commencement of baseline air quality monitoring, and will be calibrated at
bi-monthly intervals throughout all stages of the impact monitoring.
·
Calibration records are shown in Appendix E.
1-hour TSP Monitoring
Measuring Procedures
2.6
The measuring procedures of the 1-hour dust meter
are in accordance with the Manufacturer’s Instruction Manual as follows:
·
Set POWER to “ON”, push BATTERY button,
make sure that the meter’s indicator is in the range with a red line and allow
the instrument to stand for about 3 minutes (Then, the air sampling inlet has
been capped).
·
Push the knob at MEASURE position.
·
Push “O-ADJ” button. (Then meter’s indication is 0).
·
Push the knob at SENSI ADJ position and set the meter’s indication to S
value described on the Test Report using the trimmer for SENSI ADJ.
·
Pull out the knob and return it to MEASURE position.
·
Push “START” button.
Maintenance and Calibration
·
The 1-hour TSP meter would be checked at 3-month intervals and
calibrated at 1-year intervals throughout all stages of the air quality
baseline monitoring. Calibration records are shown in Appendix E.
Monitoring Results
2.7
The monitoring results for 1-hour TSP and 24-hour
TSP are summarized in Table 2.4 and 2.5 respectively and the monitoring results
are provided in Appendix F.
Table 2.4 Summary of 1-hour
TSP Monitoring Results in the Reporting Period
|
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level
(mg/m3)
|
Limit Level (mg/m3)
|
|
CA1
|
77.0
|
70.0
– 83.2
|
309.3
|
500
|
|
CA2
|
74.6
|
68.3
– 81.2
|
319.6
|
500
|
Table 2.5 Summary of 24-hour
TSP Monitoring Results in the Reporting Period
|
|
Average (mg/m3)
|
Range (mg/m3)
|
Action Level
(mg/m3)
|
Limit Level (mg/m3)
|
|
CA1
|
29.7
|
16.5
– 36.1
|
166.8
|
260
|
|
CA2
|
34.6
|
21.4
– 69.5
|
187.0
|
260
|
2.8
Air quality monitoring was
carried out for both 1-hour TSP and 24-hour TSP at all the monitoring stations
in the reporting month.
2.9
The air quality monitoring results, in terms of
1-hour TSP and 24-hour TSP, were below the action and limit level at both
monitoring locations in the reporting month. The event action plan is annexed
in Appendix G.
2.10
Weather information including wind speed and wind
direction is annexed in Appendix H. The information was obtained from Hong Kong
Observatory Victoria Peak Automatic Weather Station and Central Pier Anemometer
Station.
Monitoring Requirements
3.1
In accordance with the EM&A Manual, impact noise levels should be
obtained at 2 noise monitoring stations. Impact noise monitoring was conducted
for at least once per week during the construction phase of the Project. The Action
and Limit level of the noise monitoring is provided in Appendix D.
Monitoring Equipment
3.2
Integrating Sound Level Meter was employed for noise monitoring. They were Type 1 sound level meters capable
of giving a continuous readout of the noise level readings including equivalent
continuous sound pressure level (Leq) and percentile sound pressure
level (Lx). They comply with International Electrotechnical Commission
Publications 651:1979 (Type 1) and 804:1985 (Type 1). Portable electronic wind speed indicator
capable of measuring wind speed in m/s was employed to check the wind
speed. Table 3.1 details the noise
monitoring equipment used.
Table 3.1 Noise Monitoring
Equipment
|
Equipment
|
Model
|
|
Integrating
Sound Level Meter
|
Rion
NL-31
|
|
Calibrator
|
Rion
NC-73
|
Monitoring Locations
3.3
Two monitoring stations were set up in accordance
with EM&A Manual. Table 3.2 describes details of the two monitoring
stations. The monitoring locations are shown in Figure 2.1.
Table 3.2 Locations of Noise
Monitoring Stations
|
Monitoring Station
|
Identity / Description
|
|
CN1
|
Block
A, Po Shan Mansions
|
|
CN2
|
Block
A, Po Shan Mansions
|
Monitoring Parameters
3.4
One set of 30-mins measurement at each monitoring station between 0700
and 1900 on normal weekdays at a frequency of once per week was required to
determine the impact noise level. Leq, L10 and L90
would be recorded.
Monitoring Methodology
Monitoring Procedures
·
The Sound Level Meter was set on a tripod at a
height of 1.2 m above the ground.
·
Façade measurements were made at all three monitoring
locations.
·
The battery condition was checked to ensure the
correct functioning of the meter.
·
Parameters such as frequency weighting, the time
weighting and the measurement time were set as follows:
-
frequency weighting: A
-
time weighting: Fast
-
time measurement: Leq(30 minutes) during
non-restricted hours i.e. between 07:00 and 19:00 on normal weekdays
·
Prior to and after each noise measurement, the
meter was calibrated using a Calibrator for 94 dB at 1000 Hz. If the difference in the calibration level
before and after measurement was more than 1 dB(A), the measurement would be
considered invalid and repeat of noise measurement would be required after
re-calibration or repair of the equipment.
·
The wind speed was frequently checked with a
portable wind meter.
·
During the monitoring period, the Leq ,
L10 and L90 were recorded. In addition, site conditions and noise
sources were recorded on a standard record sheet.
·
Noise measurement was paused during periods of high
intrusive noise (e.g. dog barking, helicopter noise) if possible. Observations
were recorded when intrusive noise was unavoidable.
·
Noise monitoring was cancelled in the presence of
fog, rain, wind with a steady speed exceeding 5 m/s, or wind with gusts exceeding 10 m/s.
Maintenance and Calibration
·
The microphone head of the sound level meter and
calibrator is cleaned with soft cloth at quarterly intervals.
·
The meter should be checked and calibrated at yearly intervals.
·
Calibration details for the sound level meter and calibrator are
provided in Appendix E.
Monitoring Results
3.5
The monitoring results for noise are summarized in
Table 3.3 and the monitoring data is provided in Appendix I.
Table 3.3 Summary of Noise
Monitoring Results in the Reporting Period
|
|
Average, dB(A), Leq (30 mins)
|
Range, dB(A), Leq (30 mins)
|
Limit Level, dB(A), Leq (30 mins)
|
|
CN1
|
62.1
|
61.0
– 63.9
|
75.0
|
|
CN2
|
61.1
|
60.0
– 62.5
|
75.0
|
3.6
There was no noise complaint received in the reporting month, hence, no
action level exceedance was recorded. At both monitoring locations, CN1 and CN2,
all the monitoring results (daytime) were below the limit level of 75 dB(A).
3.7
All the monitoring results lied within the range of the predicted noise
levels in the EIA report.
3.8
Major noise sources during the noise monitoring included the
construction activities from the Project and another project under the same
contract (concurrent project) carried out in the vicinity and nearby traffic
noise.
Monitoring Requirement
4.1
As required under Environmental Permit No. EP-235/2005/B, the Permit
Holder is required to carry out monitoring of the plant species of conservation
interest to check on the health and condition of the plants twice a month
during the construction period of the Project.
4.2
It is required to undertake the ecological tasks to fulfill the
requirements of the Environmental Permit (EP).
As required by Conditions 2.11 and 3.5 of the EP, a suitably
qualified ecologist with 7 or more years of relevant experience shall be
employed to conduct the ecological monitoring.
Monitoring Location
4.3
The ecological monitoring was carried out for plant individuals of
conservation interest identified within the proposed works area.
Monitoring Methodology
4.4
The ecological monitoring was conducted twice in the reporting month on
2 June 2009 and on 23 June 2009 by Ms. Gigi C C Lam, who had over 7 years of
relevant ecological experience.
4.5
The plants of conservation interest, which were tagged during the
baseline survey, were checked during each monitoring.
Monitoring Results
4.6
Soil nailing works and construction of buttress wall were in progress
during the monitoring visits.
4.7
During monitoring visit on 2 June 2009, a number of vegetation of
conservation interest were missing from site, including V057, V058, V063, V056,
V054, V055, V052, and V042. And some
others were not fenced off, including V065, V051, V053, V048, V049, V050, V043,
V044, V045, V046, and V047. The missing
vegetation were subsequently found and tagged in 23 June 2009 visit apart from
V054. The eleven unprotected were also
fenced off.
4.8
A vegetation of conservation V018 located during the May 2009 monitoring
visit was still in very poor condition.
4.9
Soil of natural terrain along an access road (near Row AH) was not well
covered.
Monitoring Requirement
5.1
During the construction
phase of the Project, landscape and visual monitoring should be carried out
bi-weekly by a Registered Landscape Architect (RLA) to check if the design,
implementation and maintenance of the landscape and visual mitigation measures
are fully realized. A detailed report is annexed in Appendix J.
Summary of Inspection – 2 June 2009
Matters Arising from Previous Inspections
5.2
The Contractor had removed
safety ropes previously observed tied around the base of several existing
trees.
5.3
Removal of the termite
infected dead tree T534 along the footpath stair was still outstanding. The Contractor was reminded to urgently
remove the infected dead tree as soon as possible.
5.4
It was still observed that
no further rectification of tree ID numbers was carried out since the last
couple of inspections. The Contractor
was reminded to rectify the missing tree ID numbers on the remaining existing
trees as soon as possible.
5.5
It was noted that
compensatory planting proposal for the replacement of dead tree T611 was
outstanding. The Contractor was
recommended to seek Engineer’s agreement on the replacement planting as soon as
possible.
5.6
It was noted that the
Contractor’s clarification of the status of existing trees T516, T517, T666,
and T698 located immediately outside of the works boundary was
outstanding. The Contractor was reminded
to provide necessary information as soon as possible.
Protection of Existing Trees
5.7
It was observed that soil
was compacted against the base of a small existing tree on the upper slope side
and used as passage area. The Contractor
was reminded the practice was unacceptable and the compacted soil is to be
removed and constructed with proper passage without affecting the existing tree
if required.
Recommendations
5.8
The Contractor was
recommended to remove the dead tree T534 from site for safety considerations,
especially the tree was found infected by termite. The Contractor was also reminded to record
and report all dead trees as found on site to the Engineer for record.
5.9
The Contractor was again
reminded to rectify all remaining ineligible tree ID numbers for all existing
trees.
5.10
The Contractor was again
reminded d to clarify the status of missing trees as soon as possible.
5.11
The Contractor was again
reminded to seek Engineer’s agreement on the replacement planting for dead
tree.
5.12
The Contractor was
recommended to clear the compacted soil at the base of existing tree and
construct proper passage if required, without affecting the tree.
Summary of Inspection – 16 June 2009
Matters Arising from Previous Inspections
5.13
The Contractor had removed
the compacted soil away from the base of existing tree identified at the last
inspection.
5.14
The Contractor had removed
the termite infected dead tree T534 from site.
5.15
The Contractor had further
rectified the tree ID numbers on site, with approximately 60% completed. The Contractor was reminded to finish the
rectification of missing tree ID numbers works for the remaining existing trees
as soon as possible.
5.16
It was noted that
compensatory planting proposal for the replacement of dead tree T611 was
outstanding. The Contractor was
recommended to seek Engineer’s agreement on the replacement planting as soon as
possible.
5.17
It was noted that the
Contractor’s clarification of the status of existing trees T516, T517, T666,
and T698 located immediately outside of the works boundary was
outstanding. The Contractor was reminded
to provide necessary information as soon as possible.
Protection of Existing Trees
5.18
It was observed that the
Contractor had tied ropes to the base of existing tree T668 for support of the
large air hose. The Contractor was
requested to remove the rope from the base of the tree.
5.19
It was observed that an
existing tree on the slope which had partially grown above an existing boulder was
undermined by the recent removal of the boulder due to engineering safety
considerations. The tree root system is
now partially undermined and exposed, which would lead to dry-out and possible
collapse during strong winds and typhoons.
The Contractor was recommended to back-filled the pit and compact the
slope surface area to stabilize the tree.
Recommendations
5.20
The Contractor was reminded
to rectify all remaining ineligible / missing tree ID numbers for all existing
trees.
5.21
The Contractor was again reminded
to clarify the status of missing trees as soon as possible.
5.22
The Contractor was again
reminded to seek Engineer’s agreement on the replacement planting for dead
trees.
5.23
The Contractor was reminded
to remove the ropes from the base of tree T668 and not to tie ropes in future
as support for any works on site.
5.24
The Contractor was
recommended to back-fill the pit caused by removal of boulder and to stabilize
the tree.
Summary of Inspection – 23 June 2009
Matters Arising from Previous Inspections
5.25
The Contractor had un-tied
the rope around the base of existing tree T668 and the support for the large
air hose was removed.
5.26
Backfilling of the pit on
slope exposed by the removal of the boulder below existing tree was still
outstanding. The Contractor was reminded
to rectify the condition in order to minimize the possibility of the roots
drying out and possible collapse during strong winds.
5.27
The Contractor had further
rectified the tree ID numbers on site, with approximately 60% completed. The Contractor was reminded to finish the
rectification of missing tree ID numbers works for the remaining existing trees
as soon as possible.
5.28
It was noted that
compensatory planting proposal for the replacement of dead tree T611 was
outstanding. The Contractor was
recommended to seek Engineer’s agreement on the replacement planting as soon as
possible.
5.29
It was noted that the
Contractor’s clarification of the status of existing trees T516, T517, T666,
and T698 located immediately outside of the works boundary was outstanding. The Contractor was reminded to provide
necessary information as soon as possible.
Protection of Existing Trees
5.30
It was observed that the
make-shift materials conveyor system had its edge board encircled an existing
tree, with the tree trunk being easily damaged by the conveyor ‘boat’. The Contractor was requested to rectify the
edge board to ensure that conveying of materials would not damage the tree
trunk.
Recommendations
5.31
The Contractor was reminded
to rectify all remaining ineligible / missing tree ID numbers for all existing
trees.
5.32
The Contractor was again
reminded to clarify the status of missing trees as soon as possible.
5.33
The Contractor was again
reminded to seek Engineer’s agreement on the replacement planting for dead
trees.
5.34
The Contractor was
recommended to rectify the edge board of the make-shift conveyor system in
order to minimize potential damage to the existing tree.
Next Landscape and Visual Audit Schedule
5.35
The landscape and visual
audits in the next reporting month was tentatively scheduled to 14 and 28 July
2009.
Site Inspection
6.1
Site Inspections were
carried out on a weekly basis to monitor the implementation of proper
environmental pollution control and mitigation measures for the Project. In the
reporting month, 5 site inspections were carried out on 2, 9, 16, 23 and 30 June
2009. The detail findings of the landscape and visual audits in the reporting
month are presented separately in Section 5. The environmental site inspection
summaries are attached in Appendix K. Particular observations are described
below.
Air Quality
6.2
Some of the temporary
exposed slopes at Row R were not properly covered. The Contractor was reminded
to properly cover all exposed slopes.
Noise
6.3
No adverse observation was
identified in the reporting month.
Water Quality
6.4
Loose sediment was observed
accumulated on the platform at Row X, Row AF and Row AH. The Contractor was
reminded to clear the sediment regularly and as soon as the soil nailing
operation finishes.
6.5
Sediment was observed
accumulated in the sand trap at Row C. The Contractor was advised to clear the
sediment more frequently especially during rainy seasons.
Chemical and Waste Management
6.6
A hole was found on the
drip tray at Row AA and oily water was running out. The Contractor was
requested to fix the drip tray as soon as possible.
Ecology
6.7
A plant species of
conservation interest (V018) was still in very poor condition and V054 was
missing from site.
6.8
An access road (near Row
AH) along natural terrain was not well covered.
Landscape and Visual
5.36
It was noted that
compensatory planting proposal for the replacement of dead tree T611 was
outstanding. The Contractor was
recommended to seek Engineer’s agreement on the replacement planting as soon as
possible.
5.37
It was noted that the
Contractor’s clarification of the status of existing trees T516, T517, T666,
and T698 located immediately outside of the works boundary was
outstanding. The Contractor was reminded
to provide necessary information as soon as possible.
5.38
It was observed that soil
was compacted against the base of a small existing tree on the upper slope side
and used as passage area. The Contractor
was reminded the practice was unacceptable and the compacted soil is to be
removed and constructed with proper passage without affecting the existing tree
if required.
5.39
It was observed that the
Contractor had tied ropes to the base of existing tree T668 for support of the
large air hose. The Contractor was
requested to remove the rope from the base of the tree.
5.40
It was observed that an
existing tree on the slope which had partially grown above an existing boulder
was undermined by the recent removal of the boulder due to engineering safety
considerations. The tree root system is
now partially undermined and exposed, which would lead to dry-out and possible
collapse during strong winds and typhoons.
The Contractor was recommended to back-filled the pit and compact the
slope surface area to stabilize the tree.
5.41
Backfilling of the pit on
slope exposed by the removal of the boulder below existing tree was still
outstanding. The Contractor was reminded
to rectify the condition in order to minimize the possibility of the roots
drying out and possible collapse during strong winds.
5.42
The Contractor had further
rectified the tree ID numbers on site, with approximately 60% completed. The Contractor was reminded to finish the
rectification of missing tree ID numbers works for the remaining existing trees
as soon as possible.
5.43
It was observed that the make-shift
materials conveyor system had its edge board encircled an existing tree, with
the tree trunk being easily damaged by the conveyor ‘boat’. The Contractor was requested to rectify the
edge board to ensure that conveying of materials would not damage the tree
trunk.
Assessment of Environmental Monitoring Results
6.9
All monitoring results were
audited against the Action / Limit levels and any exceedance would be validated
and issued when necessary.
6.10
The monitoring results in
the reporting period were comparable with the EIA predictions. Detailed
discussions are given in Section 2 and 3.
Advice on the Solid and Liquid Waste Management Status
6.11
The Contractor is
registered as a chemical waste producer for this Project. The Chemical Waste
Storage Area located at the Contractor’s site office area was properly
maintained in the reporting month.
6.12
As advised by the
Contractor, 7.18 ton of non-inert C&D waste and 36.20 ton of inert C&D
waste were disposed offsite to SENT landfill and Chai Wan respectively in the reporting
month. C&D waste generated was reused on site as much as possible.
Environmental Licenses and Permits
6.13
The environmental licenses
and permits for this Project and valid in the reporting month is summarized in
Table 6.1.
Table 6.1 Summary of Environmental
Licensing and Permit Status
|
Description
|
Permit No.
|
Valid Period
|
Remarks
|
|
From
|
To
|
|
Environmental
Permit
|
EP-235/2005/B
|
23/11/07
|
--
|
- Installation of about 700 nos. of soil nails and about 60 nos. of
raking drains in the natural terrain;
- Rock slope stabilisation works at upper portion of the natural
terrain; and
- Other associated works.
|
|
Registration
as a Chemical Waste Producer
|
5213-141-C3250-02
|
13/12/06
|
--
|
Spent
lubricating oil and mineral oil
|
|
Effluent
Discharge License
|
EP880/W10/XX0261
|
07/11/06
|
31/12/11
|
--
|
|
Notification
of Constriction Work under APCO (Construction Dust)
|
001012125
|
18/07/06
|
--
|
--
|
Implementation Status of Environmental Mitigation
Measures
6.14
In response to the site
audit findings, the Contractor carried out corrective actions.
6.15
A summary of the
Implementation Schedule of Mitigation Measures (EMIS) is presented in Appendix
C. Most of the necessary mitigation measures were implemented properly.
Summary of Exceedances of the Environmental Quality
Performance Limit
6.16
All 1-hour TSP, 24-hour TSP
and noise monitoring results complied with the Action / Limit levels.
6.17
No exceedance was recorded
in the reporting month.
Summary of Complaints, Notification of Summons and
Successful Prosecutions
6.18
The Environmental Complaint
Handling Procedure is annexed in Figure 6.1.
6.19
No environmental complaint, notification of summons
and successful prosecutions was received in the reporting month.
Construction Programme for the Coming Months
7.1
The construction programme
for the Project is provided in Appendix B.
7.2
The major construction work
in July 2009 will be:
-
Rock slope
stabilization works at Portion B2;
-
Soil nail
heads construction at Portion B2;
-
Soil nailing
works at Portion D; and
-
Slope
reinstatement works at Portion A1, A2, B1 and C.
Key Issues for Coming Month
7.3
Key issues to be considered
in the coming month included:
-
Sufficient dust suppression
measures should be maintained;
-
Collection of construction
waste should be carried out regularly;
-
Site runoff should be
properly collected and treated prior to discharge;
-
Construction activities
should avoid causing damage to the trees and to plants species of conservation
interest; and
-
Quieter powered mechanical
equipment should be used.
7.4
The following mitigation
measures are required:
Air Quality Impact
-
Regular watering should be
used during soil nailing;
-
Dusty material stockpiled
should be completely covered;
-
Dusty activities should be
re-scheduled if high-wind conditions encountered;
-
Open burning should be
strictly prohibited;
-
All dusty vehicle loads
transporting to, from and between site locations should be covered with
tarpaulin;
-
Vehicle wheel and body
washing facilities should be used at all exit points of the site;
-
Wind shield, dust
extraction units or water spraying should be used at the loading points.
Construction Noise Impact
-
Quieter powered mechanical
equipment should be used;
-
Insulating fabric should be
used for drill rigs during drilling process;
-
Noise generating
construction works should be carried out during daytime only;
-
Noise barriers or other
measures should be used to minimize disturbance to the bat roost;
-
Plant on site should be
properly maintained and serviced regularly;
-
Mobile plants should be
sited as far from NSRs as possible;
-
Machines and plant in
intermittent use should be throttled down;
-
Strong noise emitting
plants, wherever possible, should be oriented so that noise is directed away
from the nearby NSRs;
-
Material stockpiles,
wherever possible, should be effectively utilized to screen noise from
construction activities;
-
Movable noise barrier with
surface mass in excess of 7kg/m2
should be used for PME wherever possible;
-
Noise insulating fabric
should be adopted for drill rig operating in Works Area E.
Water Quality Impact
-
Prevent runoff water from
entering the nearby water-bodies;
-
Silt traps and oil / grease
separators should be regularly cleaned and maintained;
-
Outlet pipe extending above
the slope surface should be installed;
-
Air should be used as the
flushing medium of the drilling equipment;
-
Earth bunds or sand bag
barriers should be provided on-site to direct storm water to silt removal
facilities;
-
Exposed slope / soil
surface and opened stockpile of more than 50m3
should be covered with tarpaulin;
-
Oils and fuels should be
used and stored in designated area.
Chemical and Waste Management
-
Debris and rubbish on-site
should be collected, handled and disposed of properly;
-
Waste skips should be
provided to collect general refuse and construction wastes;
-
Soil contamination with
fuel leaked from construction plants should be removed off-site;
-
Sufficient waste disposal
points with regular collection should be provided;
-
Appropriate measures should
be provided to minimize windblown litter and dust during transportation of
waste;
-
Different containers should
be used to segregate and store different types of waste;
-
Encourage collection of
aluminum cans, PET bottles and paper by providing separate bins;
-
Unused chemicals should be
recycles wherever possible;
-
Proper storage and site
practices should be adopted to minimize the potential for damage and
contamination of construction materials;
-
Oils and fuels should be
stored in designated area;
-
Plan and stock construction
materials carefully to minimize waste generation.
Ecological Impact
-
Soil nail installation
should avoid / minimize damage of root system to the existing plants;
-
Fences should be erected
along the boundary of the works area
-
Disturbance to the natural
woodland and shrubland habitats should be minimized by preventing tipping,
vehicle movements and encroachment of personnel onto the adjacent area;
-
Permanent casing should be
provided to the drillhole of soil nail;
-
Placement of equipment or
stockpile should be located in designated areas to minimize disturbance to
natural or moderate-high ecological value habitats;
-
Construction activities
should be restricted to works areas;
-
Disturbance to existing
vegetation should be minimized wherever possible.
Landscape and Visual Impact
-
Designation of
“no-intrusion zones” and record any trespass and damage to existing vegetation;
-
Soil nails on site should
avoid tree trunks and tree roots;
-
Dust and erosion control
should be provided for exposed soil;
-
For tree planting
operations, method statement should be checked against specification
requirements;
-
All retained trees within
the working boundary should be checked regularly;
-
Control over appearance of
hoarding, construction plants / machines;
-
Security floodlights should
be carefully selected to avoid light pollution.
Monitoring Schedule for the Coming Months
7.5
The tentative schedule for
environmental monitoring in July 2009 is provided in Appendix L.
Conclusions
8.1
The construction phase of
the project commenced in April 2008.
8.2
1-hour TSP and 24-hour TSP
monitoring was carried out in the reporting month. All monitoring results
complied with the action / limit level. No exceedance was recorded.
8.3
All impact daytime noise
monitoring results complied with the limit level in the reporting month.
8.4
Environmental site inspections were carried out 5
times in June 2009. Recommendations on remedial actions were given to the
Contractor for the deficiencies identified during the site audit.
8.5
Three landscape and visual
audits were carried out in the reporting month. The Contractor had the edge
board of the make-shift materials conveyor system encircled an existing tree,
with the tree trunk being easily damaged by the conveyor ‘boat’. The Contractor was requested to rectify the
edge board to ensure that conveying of materials would not damage the tree trunk.
8.6
Two ecological audits were
carried out in the reporting month. The
Contractor was reminded to properly tag all the vegetation of conservation
interest and all tagged plants of conservation interest in the affected area should
be located and fenced off properly with clear sign to avoid any further damage
and restrict any unauthorized access of site workers to the area. All plant species of conservation within
works area should be properly fenced off and tagged before commencement of any
construction activities. Access road
should avoid natural terrain. Any newly formed access road along natural
terrain should be covered and protected with sandbags to avoid erosion.
8.7
No environmental complaint,
notification of summons and prosecution was received in the reporting month.
Recommendations
8.8
According to the
environmental site inspections performed in the reporting month, the following
recommendations were provided:
Air Quality Impact
-
Soil nail workstations on
site should be properly enclosed; and
-
Water spraying should be
provided during soil nailing works.
Construction Noise Impact
-
Nil
Water Quality Impact
-
Sedimentation tanks on site
should be properly maintained;
-
Site effluent must be
collected and treated prior to discharge to public drain;
-
U-channels should be kept
clear of mud, debris, leaves, construction waste and materials; and
-
Soil and exposed earth at
all working platforms and slopes should be cleaned up.
Chemical and Waste Management
-
Drip trays should be
provided to all plants and chemical containers on site;
-
Oils and fuels should be
stored in designated area;
-
Empty chemical containers
should be disposed of as chemical waste;
-
C&D waste, debris and
general refuse on-site should be collected, handled and disposed of properly;
and
-
Waste skips should be
provided to collect general refuse and construction wastes.
Ecological Impact
-
The Contractor was reminded
to take all necessary actions to prevent grout leakage and muddy run-off to the
surrounding natural environment;
-
All identified vegetation
of conservation interest should be preserved;
-
All site access should be
clearly demarcated and no excessive removal of vegetation in natural areas
adjacent to the site access should be allowed;
-
All plant species of
conservation interest should be fenced off and tagged properly with clear sign,
especially for those located near major access road and areas likely to be
impacted by construction activities;
-
The Contractor was recommended to take necessary
measures to prevent damage to all vegetation within the construction site; and
-
Dust and soil on vegetation should be washed away
in a timely manner.
Landscape and Visual Impact
-
The Contractor was recommended
to remove the dead tree T534 from site for safety considerations, especially
the tree was found infected by termite.
The Contractor was also reminded to record and report all dead trees as
found on site to the Engineer for record;
-
The Contractor was reminded
to seek Engineer’s agreement on the replacement planting for dead tree;
-
The Contractor was
recommended to clear the compacted soil at the base of existing tree and
construct proper passage if required, without affecting the tree;
-
The Contractor was reminded
to rectify all remaining ineligible / missing tree ID numbers for all existing
trees;
-
The Contractor was reminded
to remove the ropes from the base of tree T668 and not to tie ropes in future
as support for any works on site;
-
The Contractor was recommended
to back-fill the pit caused by removal of boulder and to stabilize the tree;
and
-
The Contractor was
recommended to rectify the edge board of the make-shift conveyor system in
order to minimize potential damage to the existing tree.
