9.1
The Project is a Designated Project (DP) under Item C.12 (b), Part I of
Schedule 2 of the EIAO (Cap. 499) – “A dredging operation which is less than
100m from a seawater intake point”. The Project will be undertaken together by
the CWB contractor. The temporary
reclamation in the Project together with that in the CWB project will be
another designated project under Item C.1, Part 1, Schedule
2 of the EIAO. This EIA report has provided an assessment of the potential
environmental impacts associated with the Project, and taken into consideration
the potential cumulative impacts from other concurrent projects.
9.2
During the EIA process, specific environmental control and mitigation
measures have been identified and incorporated into the planning and design of
the Project in order to achieve compliance with environmental legislation and
standards. An environmental monitoring and audit (EM&A) programme has also
been developed during the assessment of the Project. The key assessment
assumptions, limitation of assessment methodologies and all relevant prior
agreements with the EPD on assessment of different environmental aspects are
given in Appendix
9.1. The implementation schedule listing the recommended mitigation
measures is presented in Section 8. A summary of the key environmental outcomes
arising from the EIA study and the environmental impacts are presented in the
sections below.
9.3
A summary of the key environmental outcomes arising from the EIA study
and the environmental benefits of the environmental protection measures
recommended are tabulated in Table 9.1
below:
Table
9.1 Summary of Key Environmental
Outcomes / Benefits
|
Area / Issue |
Environmental Outcomes /
Benefits and Mitigation Measures |
|
The Project |
Requirements: The Project comprises the
following key elements: ·
Temporary
reclamation, which occupies about 0.7ha of Government foreshore and sea-bed
(of which 0.3ha is already authorized under CWB project, i.e. additional
reclamation of 0.4ha is required). ·
Dredging works
at the southeast corner of the CBTS to provide space for temporary relocation
of anchorage area due to the additional temporary reclamation for the
Project. ·
Construction of
a section of the twin track railway tunnel structure (approximately 160m
long) above the proposed CWB located entirely offshore within the CBTS. ·
Relocation of
the temporary RHKYC jetty within the CWB temporary reclamation to a new
location. ·
Removal of the
temporary reclamation, except the small area at the southwest corner of the
reclamation (which will be removed by the SCL project upon completion of the
future SCL tunnels connecting to the proposed SOV). Benefits: With the presence of the
Project, future construction of the SCL on both sides of the CWB tunnels is protected
and ensured feasible without damaging or unduly affecting the CWB tunnels
which could be operational by then. This arrangement will also minimize
public nuisance and impact to the surrounding environment as it can reduce
the reclamation area for subsequent construction of the SCL after CWB is
completed. Potential Consequences without the Project: Temporary reclamation will be required in future construction of the
Protection Works at the interfacing area with the CWB. The construction may
risk the operation of the CWB tunnel as the closest distance between the
crown of the CWB tunnel and the SCL tunnels is merely around 3m. The higher
construction risks and larger temporary reclamation area will result in a
bigger project cost compared to the scenario which the Protection Works is
constructed under the CWB project. While the temporary reclamation will be carried out after the
completion of CWB project, the size and duration of the temporary reclamation
in the CBTS will be significantly more than that of having the Protection
Works constructed under the CWB project, leading to a prolongation of impacts
to the users of CBTS, disturbance to the moorings and operations of the
typhoon shelter. |
|
Environmental Friendly
Designs Recommended to Avoid Environmental Problems |
This Project allows the SCL Protection Works to be constructed
together with the CWB works within the CBTS to achieve the following merits: ·
Use of the
temporary reclamation area provided by CWB to avoid the repeated temporary
reclamation at the interfacing area of the two projects. ·
Minimize the extent
and duration of temporary reclamation required for the construction of the
SCL tunnels. ·
Minimize waste generation
during the construction by avoiding the repeated temporary reclamation and
hence minimize the potential impact to the existing public fills and
landfills in ·
Minimize
disturbance to the moorings and operations of the typhoon shelter and
expedite the works to avoid prolongation of environmental impacts. |
|
Water Quality |
Environmental benefits of environmental
protection measures recommended: Marine Construction The worst-case scenario during the marine
construction period, taking into account the cumulative effects from other
concurrent marine works has been assessed. It was predicted that, with the
implementation of the recommended mitigation measures, there would be no
unacceptable water quality impacts due to the construction of the SCL
Protection Works and due to the cumulative effects from other concurrent
marine construction activities. Land-based
Construction Potential water quality impact due to
land-based construction would arise from the release of sediment-laden water
from surface works areas and discharge of construction site effluent. Water quality deterioration could be
minimized through the implementation of adequate mitigation measures. No
unacceptable residual impact on water quality is anticipated. Compensation areas
included: N/A. Population and
environmental sensitive receivers protected: Water sensitive receivers along the
coastlines of Wan Chai, |
|
Construction Noise |
Environmental benefits of environmental protection
measures recommended: All NSRs in the vicinity
of the Project would be protected from construction noise through the
implementation of recommended noise mitigation measures including the use of
quieter plants and movable noise barrier. There would be no exceedance throughout the Project construction period and
no residual impacts are expected. Compensation areas included: N/A Population and environmental sensitive
receivers protected: Existing NSRs including residential
blocks along Gloucester Road and southeast corner of the
typhoon shelter. |
|
Construction Dust |
Environmental benefits of environmental
protection measures recommended: All representative ASRs
within 500m of the Project Boundary would be protected from the construction dust
impact with the implementation of recommended mitigation measures, which
include watering once every working hour on temporary reclamation area of the
Project, covering/paving the retained area at the southwest of temporary
reclamation and the implementation of good site practices. Compensation areas included: N/A Population and environmental sensitive
receivers protected: Identified ASRs along |
|
Waste Management Implication |
Environmental benefits of environmental
protection measures recommended: The proposed waste
control and mitigation measures could avoid the potential water quality, dust
and noise impacts associated with the handling, transportation and disposal
of the identified wastes arising from the construction of the Project. It is estimated that approximately 14,400m3 of inert C&D materials and 300 m3
of non-inert materials would be generated during the construction phase of
the Project which would be reused (i.e. other concurrent projects) as far as
practicable before off-site disposal. Opportunities in minimization of
generation and maximization of reuse would be continually investigated during
the detailed design and construction phases.
The remainder of materials would be disposed of to designated outlets. The total volume of dredged sediment generated
from the Project is estimated to be approximately 38,200m3. Based
on the results of the chemical and biological screening, approximately 9,000m3 sediment is suitable for Type 1
– Open Sea Disposal, 18,700m3 sediment requires Type 2 – Confined Marine Disposal and 10,500m3 sediment requires Type 3 – Special
Treatment/Disposal in accordance with ETWB TC(W)
No.34/2002. The proposed handling method of dredged Type 3
sediments should adhere to the CWB project under which geosynthetic
containment would be employed as
disposal method. A proposal for the use of geosynthetic containers on Type 3 sediment should be
submitted to TCO/EPD for agreement at a later stage of the Project and prior
to the dredging works. With the implementation
of the recommended mitigation measures in accordance with the requirements of
ETWB TC(W) No.34/2002, no adverse
environmental impacts would be expected. Compensation areas included: N/A Population and environmental sensitive
receivers protected: Water quality, air and
noise sensitive receivers at or near the Project Site, the waste
transportation routes and the waste disposal site. |
Water Quality Impact
Marine Construction
9.4
The water quality impacts during the marine construction works have been
quantitatively assessed by numerical modelling. Suspended solids were
identified as the most significant water quality parameter during the marine
construction works. The worst-case scenario during the marine construction
period, taking into account the cumulative effects from other concurrent marine
works has been assessed. It was predicted that, with the implementation of the
recommended mitigation measures, there would be no unacceptable water quality
impacts due to the construction of the SCL Protection Works and due to the
cumulative effects from other concurrent marine construction activities. A
water quality monitoring and audit programme would be implemented to check the
effectiveness of the proposed water quality mitigation measures.
Land-based Construction
9.5
The key issue from the land-based construction activities would be the
potential water quality impact due to the release of sediment-laden water from
surface works areas and discharge of construction site effluent. Water quality deterioration could be
minimized through the implementation of adequate mitigation measures. Regular
site inspections should be undertaken to inspect the construction activities
and works areas in order to ensure the recommended mitigation measures are
properly implemented.
Noise Impact
9.6
The noise impact assessment in this EIA Study has predicted the
construction noise impacts of the Project during normal daytime working hours,
taking into account all other concurrent projects within a 300m assessment
area. Night-time work would not be involved in this Project. Based on the
latest available information, six representative NSRs were identified within
300m from Project Boundary. The assessment result has revealed that noise
arising from the construction activities of the Project would have unavoidable
potential impact on the NSRs located in the vicinity of the works areas.
Unmitigated construction noise levels at the representative NSRs have been
predicted, which were found to be in the range of 63 to 84 dB(A).
9.7
Mitigation
measures including good site practices, quieter plant and movable noise barrier
were recommended to reduce the noise levels so as to meet the EIAO-TM noise
criterion. With the recommended
mitigation measures in place, noise levels due to the Project and the
cumulative impact with the CWB project at all representative NSRs were predicted to comply with the EIAO-TM daytime
construction noise criterion. No residual impact would be envisaged. An
EM&A programme was also recommended to be
established according to the predicted occurrence of noisy activities.
Construction Dust Impact
9.8
Potential dust
impact associated with the construction of the Project has been assessed in
this EIA Study. A total of 6 representative ASRs are identified for this
assessment within 500m from the boundaries of all associated works areas under
the Project in accordance with the criteria set out in the EIAO-TM. Under the
Project, potential sources of dust impact would include dredging, temporary
seawall construction, filling, installation of diaphragm walls, excavation,
placing a reinforced concrete tunnel box and removal of temporary reclamation.
9.9
Under the
unmitigated scenario, the predicted cumulative maximum hourly, daily and annual
average TSP levels at most of the representative ASRs would exceed the criteria
of EIAO-TM and AQO. Proper dust mitigation measures, including watering once every working hour on temporary
reclamation area of the Project, covering/paving the retained area at the
southwest of temporary reclamation and the implementation of good site
practices, were thus proposed.
9.10
With the
implementation of the recommended dust mitigation measures, the predicted
cumulative maximum hourly, daily and annual TSP levels at all representative
ASRs would comply with the criteria in EIAO-TM and AQO. No adverse dust impacts
on the ASRs in the vicinity of the construction sites were anticipated.
Waste Management
Implications
9.11
Different types of
potential wastes likely to be generated by the Project have been identified in
this EIA Study. C&D materials (from construction of railway tunnel
structure and relocation of temporary of RHKYC jetty), sediment, general refuse
(from workforce) and chemical waste (from maintenance of construction plant and
equipment) would be generated during the construction phase. Provided that these wastes are handled,
transported and disposed of using approved methods and that the recommended
good site practices are strictly followed, adverse environmental impacts would
not be expected.
9.12
Reduction measures
have been recommended to minimise the amount of materials generated in the
Project. Approximately 14,400m3 of inert materials and 300 m3 of non-inert materials would
be generated during the construction phase of the Project which would be reused
(i.e. other concurrent projects) as far as practicable before off-site
disposal. Opportunities in minimisation
of generation and maximisation of reuse would be continually investigated
during the detailed design and construction phases. The remainder of materials would be disposed
of to designated outlets.
9.13
The total volume
of dredged sediment generated from the Project is estimated to be approximately
38,200m3. Based on the results of the chemical and biological
screening, approximately 9,000m3
sediment is suitable for Type 1 – Open Sea Disposal, 18,700m3 sediment requires Type 2 – Confined Marine Disposal and 10,500m3 sediment requires Type 3 – Special Treatment/Disposal in
accordance with ETWB TC(W) No.34/2002.
9.14
It is proposed
that the handling method of dredged Type 3 sediments should adhere to the CWB
project under which geosynthetic containment would be
employed as disposal method. The sediment should be sealed in geosynthetic
containers and disposed of at the designated contaminated mud pit. The pit would be subsequently capped thereby
meeting the requirements for fully confined mud disposal. A proposal for the
use of geosynthetic containers on Type 3 sediment
should be submitted to TCO/EPD for agreement at a later stage of the Project
and prior to the dredging works.
9.15
With the
implementation of the recommended mitigation measures and in accordance with
the requirements of ETWB TC(W) No.34/2002, no adverse environment impacts would
be expected from dredging, transportation and disposal of marine sediment.
Overall Summary
9.16
This EIA has been
conducted based on the best and latest information available during the course
of the EIA study. The findings of this EIA have provided information on the
nature and extent of environmental impacts arising from the Project. The EIA
has, where appropriate, identified mitigation measures to ensure compliance
with environmental legislation and standards.
9.17
Overall, this EIA
has demonstrated the general acceptability of the residual impacts and that the
population and environmental sensitive resources in the vicinity of the Project
will be sufficiently protected. Environmental monitoring and audit mechanisms
have been recommended before and during the construction of the Project, where
necessary, to verify the accuracy of the EIA predictions and the effectiveness
of recommended mitigation measures. A summary of the environmental impacts
associated with the Project is presented in Table 9.2.
Table 9.2 Summary of Environmental Impacts associated
with the Project
|
Sensitive
Receivers / Assessment Points |
Impact
Prediction Results |
Relevant
Standards / Criteria |
Extents
of Exceedances |
Impact
Avoidance Measures / Mitigation Measures |
Residual
Impacts (After Implementation of Mitigation Measures) |
|
Water
Quality Impact |
|||||
|
Coral communities and seawater intakes along the
coastlines of Wan Chai, |
·
The model
results indicate that full compliance with SS criterion at all the cooling
water intakes and WSD flushing water intakes would be achieved. · At the far-field coral communities,
both the predicted SS elevations and sedimentation rates would comply with
the relevant criteria. |
1.
WSD’s Water Quality
Criteria for Flushing Water at Sea Water Intakes for SS: <10 mg/l. 2. Target water quality objectives at
coral sites for SS elevations: <30% of the mean SS level. |
· Full compliance would be achieved with
the implementation of all recommended mitigation measures. |
·
Deployment
of silt curtains at appropriate dredging areas to control sediment plume
dispersion away from the site. ·
Use of closed grab dredger to minimize the release of
sediment and other contaminants during dredging. ·
Silt screens
will be installed at the cooling water intakes within the CBTS during the
temporary reclamation period. · No more than two dredgers (of about 8m3
capacity each) should be operated for dredging
within the typhoon shelter at any time of the Project. The combined dredging
rate for all concurrent works within the CBTS shall not exceed 6,000 m3
per day throughout the entire construction period. |
None |
|
Noise
Impact (Construction Phase) |
|||||
|
Existing residential blocks along Gloucester Road and near
the southeast corner of the typhoon shelter. Six assessment points
(refer to Figure Nos. NEX2213/C/331/ENS/M52/
501 – 502) |
Predicted
noise levels would range from 63 to 84 dB(A) |
EIAO-TM assessment
criterion for works during non-restricted hours for domestic premises: 75dB(A) |
Exceed the EIAO-TM noise
criterion by up to 9 dB(A) |
Adoption of good site practices,
quiet equipment and movable noise barriers to minimise construction noise impact
|
None |
|
Construction
Dust Impact |
|||||
|
Existing commercial, residential and recreational
developments along Gloucester Road and near the typhoon shelter. Five assessment points
(refer to Figure No. NEX2213/C/331/ENS/M60/
501) |
1-hour Average TSP Conc.: 370 –
1969 µg/m3 24-hour Average TSP Conc.: 206 –
894 µg/m3 Annual Average TSP Conc:
77.0 – 84.5 µg/m3 |
EIAO-TM (hourly): AQO (daily): 260 µg/m3 AQO (annual): 80 µg/m3 |
Exceed EIAO-TM (hourly) criterion
by up to 1469 µg/m3 Exceed AQO (daily) by up to
634µg/m3 Exceed AQO (annual by up to 4.5
µg/m3 |
· Watering once on the temporary reclamation area of the
Protection Works for every working hour · Covering/paving the southwest retained area of temporary
reclamation once filling is completed · Dust suppression measures stipulated in the Air Pollution
Control (Construction Dust) Regulation and good site practices would be
carried out to further minimize construction dust impact. |
None |
|
Waste Management
Implications |
|||||
|
Water quality, air and noise sensitive receivers at or
near the Project Site, the waste transportation routes and the waste disposal
site. |
Main
waste: Dredged marine sediment with a total volume of approximately 38,200 m3 Other wastes: · C&D Materials from demolition and excavation works
with a total volume of approximately 14,400 m3 · 300 m3 of non-inert C&D material · General refuse from workforce · Chemical waste from plant and equipment maintenance |
· Waste Disposal Ordinance (Cap. 354); · Waste Disposal (Chemical Waste) (General) Regulation (Cap.
· Land (Miscellaneous Provisions) Ordinance (Cap. 28); · Public Health and Municipal Services Ordinance (Cap. 132)
- Public Cleansing and Prevention of Nuisances Regulation; · Waste Disposal (Charges for Disposal of Construction
Waste) Regulation (Cap. 354N); and · Dumping at Sea Ordinance (Cap. 466). |
Not
applicable. |
· C&D
wastes would be reused (i.e. other concurrent projects) as far as practicable
before off-site disposal · Contaminated dredged sediment (Category M and H) would
require either Type 1 – Open Sea Disposal (Dedicated Sites) or Type 2 –
Confined Marine Disposal at contaminated mud pit allocated by MFC. Category L
sediment is suitable for Type 1 – Open Sea Disposal at gazetted marine
disposal ground allocated by MFC. · The handling method of dredged Type 3 sediments should
adhere to the CWB project under which geosynthetic containment would be
employed as disposal method. The sediment should be sealed in geosynthetic
containers and disposed of at the designated contaminated mud pit. The pit would be subsequently capped
thereby meeting the requirements for fully confined mud disposal. · Other waste reduction measures and good site practices to
achieve avoidance and minimization of waste generation from the Project are
discussed in detail in Section 6.60 to 6.92. |
None |