1.1.1.1
The EMSD Hong Kong Workshop Project is to construct and
operate a temporary vehicle workshop facility for around 5 years to replace the
existing EMSD Hong Kong Workshop in Causeway
Bay. The site is located in a largely
industrial area of Sheung On Street, Chai Wan but is in proximity to
residential and institutional sensitive receivers. The location plan of this Project is
shown in Figure 1.1. The site constitutes an area of
previously developed reclaimed land which is currently unoccupied and covered
in hardstanding, with some trees.
This Executive Summary highlights the key findings of the Environmental
Impact Assessment (EIA) for the Project to comply with the EIA Ordinance
(EIAO).
2.1
Project Nature and Scope
2.1.1.1
The proposed EMSD
Hong Kong Workshop will be a single storey building comprising various facilities for vehicle repair and
maintenance operation as well as parking of vehicles when not in
operation. The facility will occupy
a site area of about 2,040 m2 and the vehicle repair and maintenance
areas will be covered by a steel shelter with a 5.2 m high clearance. The rest of site will, also, be covered by
hardstanding as part of the access road and parking bays.
2.1.1.2
This Project is
a designated project under Item A.6, Part I, Schedule 2 of the EIAO: “A
transport depot located less than 200 m from the nearest boundary of an
existing or planned (a) residential area; (b) place of worship; (c) educational
institution; or (d) health care institution” and requires an Environmental
Impact Assessment (EIA) to be undertaken and an Environmental Permit (EP) to be
obtained prior to construction commencement.
2.1.1.3
An application for the EIA Study Brief under section 5(1) of
the Environmental Impact Assessment Ordinance (EIAO) was submitted by the EMSD
on 13 June 2011 with a Project Profile (No. PP-442/2011). The EIA Study Brief No. ESB-231/2011 was
issued by the Environmental Protection Department (EPD) on 20 July 2011.
2.2
Project Scheme Selection
2.2.1
Design of Workshop
2.2.1.1
The size of this
proposed single-storey workshop is small (only about 2,040 m2) and
the flexibility to distribute individual repairing and maintenance processes
within the workshop is comparatively low.
The following design options were considered and reviewed, however, in
order to optimise the operational and environmental benefits of the facility:
·
The optimisation
of the design to service a smaller number and types of vehicles (small and
light vehicles, i.e. motorcycle, saloon cars and light vans) in the workshop in
order to reduce any potential environmental issues during the operational
phase, e.g. vehicular emissions, noise, wastewater, chemical waste, etc;
·
The use of a simple open steel shed design instead of a
typical building design of the workshop so as to reduce the duration of
construction works and hence potential environmental impacts during the
construction phase, e.g. construction dust, noise, site effluent, C&D
waste, etc; and
·
The enhancement of utilising natural ventilation by
providing a 5.2m high clearance instead of using mechanical ventilation systems
for local exhaust of emissions from the workshop so as to minimise any
potential noise impacts to the nearby sensitive receivers during the
operational phase.
2.2.2
Construction Methodology
2.2.2.1
Construction of the workshop would be comparatively
uncomplicated as it mainly involves the erection of a shed, underneath which
the vehicle repairing and maintenance activities would be carried out. As such, consideration of alternatives
was focused on the design of the foundation works and two typical construction
methods being studied and compared, namely Steel-H Driven Piling and Raft
Foundations:
·
Steel-H Driven Piling: the strict control on the use of
percussive piling methods in Hong Kong
under the Noise Control Ordinance which limits the time per day for carrying
out piling works, would pose significant implications to the construction
programme. In terms of
environmental issues, based upon the above, Steel-H driven piling is
anticipated to bring in the following potential environmental benefits: (1)
comparatively less excavated C&D materials arising; and (2) better site
control and, hence, lower risk of site effluent runoff during the rainy season
due to smaller exposed soil surfaces.
Notwithstanding these minor benefits, there are some notable downsides
to the use of percussive piling.
The most notable is the significant noise and vibration impacts that
would be caused due to the mechanical impaction induced by the hydraulic
hammer. In addition, the
limited times for undertaking percussive piling would affect the programme as
noted above and therefore prolong the noise impacts to adjacent sensitive receivers. Also, potential construction dust
impacts could be experienced as a result of soil excavation of soil for the
construction of the pile caps; and
·
Raft Foundation: While the raft foundation may increase the
amount of excavated C&D materials arising, present a slightly bigger
challenge to control the potential risk of site effluent runoff and have a
slightly higher potential construction dust impacts due to the larger exposed
soil surfaces, this method does have the benefit of notably reducing the noise
and vibration impacts as no percussive piling machines will be used.
2.2.3
Preferred Option
2.2.3.1
Based on the above considerations of the design and
construction methodology options, a preferred option has been selected in the
Scheme and Preliminary Design phases of this Project as summarised below and
shown in Figures 2.1-2.4, based on
which the detailed design of this project will proceed and this EIA study was
carried out:
·
Optimum design for small servicing capacity of vehicles,
simple open steel shed facility and natural ventilation for emissions exhaust;
and
·
Optimum construction methodology using raft foundation.
2.2.3.2
This preferred option is determined based on the comparison
of the environmental benefits and dis-benefits of the various options and
alternatives and has been selected on the basis that it minimises environmental
impacts and presents overall environmental benefits over the other options and
is considered the optimum scheme from an environmental perspective.
2.3
Preliminary Construction
Programme
2.3.1.1
The construction works would be scheduled to commence in
August 2012 for the operation of the Workshop tentatively before June
2014.
3.1.1.1
The EIA Study was conducted in accordance with the EIAO
Study Brief No. ESB-231/2011, following the guidelines on assessment
methodologies in the Technical Memorandum on Environmental Impact Assessment
(EIAO-TM). The relevant aspects of
the existing environment have been identified and described to provide a
baseline for the identification and prediction of potential impacts which are
likely to arise from implementing the Project. Individual aspect assessments have been
undertaken with computer models to quantitatively predict environmental impacts
for air quality and noise during the construction and operational phases. The predicted changes and effects
resulting from the proposed Project have been evaluated. Mitigation measures have been
identified and evaluated to avoid the impacts in the first instance to control,
reduce and minimise or remedy the impacts.
3.2
Noise
Construction Phase
3.2.1.1
Potential noise emission would be generated from
construction works activities.
Powered mechanical equipment (PME) including excavators and cranes would
be the major noise sources. Construction
noise assessment was conducted in accordance with the EIAO-TM and the Technical Memorandum (TM)
on Noise
from Construction Work other than Percussive Piling. The unmitigated scenario showed that the
construction airborne noise impact at respective NSRs ranges from 65 dB(A) to
77 dB(A), resulting in exceedances at 2 NSRs but the exceedances can be
mitigated by using quieter PME and noise barrier/enclosure and acoustic
fabric. Mitigated scenario showed
that the construction noise impact at the NSRs would reduced to 58 dB(A) to 70
dB(A). As such, no adverse impact
would be anticipated at the NSRs during construction phase of the Project.
Operational Phase
3.2.1.2
During operational phase, assessment was conducted in
accordance to the TM for the Assessment of Noise from Places Other Than
Domestic Premises, Public Places or Construction Sites. Noise emission would only be anticipated
to generate during the speedometer calibration of motorcycles. The assessment showed that the
speedometer calibration, which is anticipated to be carried
out for only
once per day and the testing would only last for 1 minute, resulting in
an
operational airborne noise level at the NSRs ranging from 43 dB(A) to 68
dB(A), indicating an exceedance of 3 dB(A) at NSR 8 Planned
Educational Institute which would be located at the immediate vicinity to the
western boundary of this proposed Workshop. However, it would not cause significant
impact to the NSR after implementation of appropriate noise barrier
within the proposed Workshop and an additional noise barrier in form of a noise
curtain hanging from the supporting frame at the western site boundary. In addition, the vehicular traffic
entering and exiting the workshop is anticipated to be small, about 50 vehicles
per day, and therefore it would not cause significant impact to the large
amount of external traffic (about 23,000 per day) at Wing Tai Road. As such, no adverse impact would be
anticipated at the NSRs during operational phase of the Project.
3.3
Air Quality
Construction
Phase
3.3.1.1
The potential dust emission sources would be mainly from the
construction work activities of the excavation and wind erosion at the work
site. As the size of the work site
is limited and the excavation is minor such that the amount of excavated materials
generated would be small, adverse dust impact would not be anticipated at the ASRs with the implementation of
sufficient dust suppression measures as stipulated under the Air Pollution
Control (Construction Dust) Regulation and good site practices. As such, a
quantitative dust impact assessment has not been considered as being
required. With the implementation
of sufficient dust suppression measures as stipulated under the Air Pollution
Control (Construction Dust) Regulation and good site practices, no adverse
residual impacts during the construction phase of the Project is expected.
Operational
Phase
3.3.1.2
Comprehensive modelling was undertaken and the air quality
background level for the future year of 2014 have been selected as the
worst-case assessment year for this air quality impact assessment, which was selected based on the results of a sensitivity test..
Emissions from the
traffic on nearby open roads within 500m from the study
area, nearby two bus depots and this Project were predicted using the CALINE4 and ISCST3 models to calculate the
emission concentrations of NO2 and RSP. The results were then combined with the background concentrations calculated from
the data of EPD’s Air Quality Monitoring Station in Kwun Tong. The predicted overall cumulative 1-hour, 24-hour and annual
average concentrations of NO2, and the 24-hour and annual average concentrations of RSP ranged from
101 to 161 g/m3, 62 to 76 g/m3, 60.3 to 65.5 g/m3,
51 to 56 g/m3 and 50.1 to 52.2 g/m3 respectively. The findings indicated that the
predicted NO2 and RSP levels at the ASRs would comply with the
relevant criteria in EIAO-TM and AQOs, so there would be no adverse residual
impact predicted and no mitigation measures are required. No adverse residual impacts during the
operational phase of the Project is expected.
3.4
Water Quality
Construction Phase
3.4.1.1
Potential water pollution sources were identified as
construction site runoff, accidental chemical spillage and sewage from
workforce. Measures including the
implementation of good site practices to control site runoff, preventive
measures for chemical use and storage and emergency spillage plan, and
provision of chemical toilets for construction workforce were recommended to
mitigate any adverse water quality impacts. No significant impacts would therefore
be anticipated.
Operational Phase
3.4.1.2
During the operational phase, there would be no direct
discharge of wastewater into the nearby WSRs. Potential water pollution sources during
the operational phase would the sewage and wastewater from the Workshop’s
operation from staff and repairing and maintenance activities. With the implementation of the
wastewater treatment facilities, no adverse water quality impact would be
anticipated.
3.5
Waste Management Implication and Land
Contamination
Construction Phase
3.5.1.1
Construction wastes of the Project would include
construction and demolition (C&D) materials including excavated C&D
materials suitable for public fill, C&D waste including cleared vegetation
which is not suitable for public fill, chemical waste, and general refuse.
Opportunities to re-use materials have been considered and
approximately 20 tonnes of sand and aggregate and approximately
75 tonnes of
excavated materials will be reused as backfill for this Project.
3.5.1.2
Measures have been recommended for adoption
to minimise the generation of C&D materials at the outset during the design
stage. As excavation cannot be
avoided, only a few measures can be taken to minimise the quantity of C&D
materials. Alternative design of
the Workshop has been adopted to minimize the generation of C&D
materials.
3.5.1.3
With the implementation of the recommended waste management
measures, no adverse residual impacts from the handling, storage,
transportation or disposal of the waste generated by the project are predicted.
3.5.1.4
No land contamination impacts
have been identified during the construction phase of the Project.
Operational Phase
3.5.1.5
The main types of waste generated during the operation of
the Project would be the general refuse, chemical waste from the repairing and
maintenance activities of the workshop and staff. No significant waste implications during
the operational phase are predicted with the implementation of recommended
waste management measures.
3.5.1.6
Preventive and precautionary
measures have been recommended for the implementation during the operation of
the Workshop to avoid land contamination due to the repairing and maintenance
activities.
3.6
Landscape and Visual
Construction
Phase
3.6.1.1
There would be moderate impacts
on LR6-2 Open Space Vegetation due to felling of 10 trees which belong to very
common and widespread species, and slight impacts on LR7-1 Open Space Vacant
Land due to loss of approximately 2,040 m2 of LR7-1 (open space/vacant land,
i.e. the Project site) during the construction phase of the Project, However,
after felling of 10 trees and removal of some dead/ weedy trees, the site and
the proposed development would still be well screened on the southern boundary
by the retained trees and the existing footbridge. The resulting landscape and/or visual
impacts from proposed tree felling without mitigation measures (e.g. on-site
tree compensation) are still considered low. With proper implementation of the
mitigation measures as recommended in the EIA Report, namely erection of
construction site hoardings, landscape/visual impacts to the VSRs at road-side
level can be effectively minimized.
Operational
Phase
3.6.1.2
Given the temporary nature and
scale of the project, the proposed development would not have any impacts on
existing off-site landscape resources and landscape character areas, while
on-site landscape impacts would be limited to felling of ten common tree
species and removal of some weedy/dead trees and temporary loss of open space
(the Project site). With the
limited size of the Project site and the land use as a workshop, no space would
be allowed for on-site tree compensation for the proposed felling of the 10
native trees. However, after
felling of these 10 trees and removal of some dead/weedy trees, the site and
the proposed workshop would still be well screened at the southern boundary by
the retained trees and existing footbridge. The resulting landscape and/or visual
impacts from proposed tree felling without mitigation measures (e.g. on-site
tree compensation) are still considered low. Off-site tree compensation would be
implemented at the EMSD Tuen Mun Vehicle Servicing Station, 202 Lung Mun Road, Siu Lang Shui, Tuen
Mun. The compensatory planting
regime would include the planting of thirty-one (31) heavy standard trees
(assuming of trunk diameter at least 75mm) of aggregated trunk diameters of
2,325mm to compensate the 10 trees loss (of aggregated trunk diameters 2,321mm)
due to the proposed Project. Other
mitigation measures would include the use of
low-rise structures/facilities (including the steel cover and facilities) which
would be constructed in dull and light green color to resemble the original
greenery of provided by the sparse vegetation of the existing Project site. Rolling plastic curtains made of durable
and non-reflective materials would be installed along the western site boundary
of the proposed Workshop to effectively screen off the operational activities
such that the maintenance activities wouoldnot be visible to the users of the
proposed educational institute (i.e. VSR-O6) during the possible 10-month
concurrent operational period of both sites.
3.6.1.3
Due to the limited footprint of
the Project site and the existing development setting, the Project site would
only be occasionally/rarely viewed by most of the identified visually sensitive
receivers (VSRs) in the study area.
Except for the travellers at Sheung On Street who are considered to have
low to medium sensitivity to visual change to the Project site, other
identified VSRs are considered to have low sensitivity to visual change to the
Project site.
3.6.1.4
The proposed Project is
considered to have slight to moderate impacts on the travellers at Sheung On
Street, and low to slight impact to
the potential VSR-O6 The Proposed Education Institute at Junction of Shing Tai
Road and Wing Tai Road
during the approximate 10-month concurrent operational period. However, the impacts are generally
considered “enhanced impacts”, as the Project would convert the existing site
(a vacant site overgrown with weeds) of low amenity value to a neat,
tidy-looking site (a maintenance workshop with a steel shelter) which is
possibly considered of higher amenity value to the viewers. The proposed scheme is considered to
have only slight to negligible impacts to the remaining VSRs in the study area
during the approximate five-year operational period. As the site can be resumed for its
originally planned uses in the Outline Zoning Plan, no long-term operational phase
impacts on visual and landscape resources and/or visually sensitive receivers
are anticipated.
4.1.1.1
An environmental monitoring and audit (EM&A) programme
will be implemented during the construction and operation of the Project, to
check the effectiveness of the recommended mitigation measures and compliance
with relevant statutory criteria.
The EM&A procedures are required during construction and operational
phases of the project implementation.
The EM&A requirements are divided into environmental monitoring and/or
project auditing in the form of site inspection and supervision. Only monitoring for construction phase
noise has been recommended but regular auditing for all other parameters would
be required. The proposed
monitoring parameters are given in Table 4.1 below:
Table 4.1: Proposed
Environmental Monitoring during Construction Phase
|
Environmental Aspects
|
Phase
|
Monitoring Parameter
|
|
Airborne Noise
|
Construction
|
Leq-30min
|
5.1.1.1
This EIA study has identified and assessed potential
environmental impacts of the Project, in accordance with the EIA study brief
and EIAO-TM guidelines. Overall, the
EIA study has concluded that the Project would be environmentally acceptable,
in compliance with environmental legislation and standards. With the implementation of environmental
control measures during construction and operational phases, there would be no
adverse residual impacts from the Project.
This will be checked by a comprehensive EM&A programme.
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