13.1.1
This EIA report has
provided an assessment of the potential environmental impacts associated with
the construction and operation of the Project based on the preliminary
engineering design information available. The assessment has been
conducted, in accordance with the Study Brief No. ESB-317/2019 under the EIAO for the Project,
covering the following environmental issues:
·
Air Quality Impact;
·
Noise Impact;
·
Water Quality Impact;
·
Waste Management Implications;
·
Land Contamination;
·
Ecological Impact;
·
Landscape and Visual Impact; and
·
Hazard to Life.
13.1.2
The findings of this EIA
Study have determined the likely nature and extent of environmental impacts
predicted to arise from the construction and operation of the
Project. 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 during both the construction and operation
phases. An EM&A programme has also been
developed. The Implementation Schedules listing the recommended
mitigation measures are presented in the Appendix 11A. A summary of
the environmental impacts identified in this EIA and key assessment and limitation
of assessment methodologies are provided in Appendix 13A and Appendix
13B respectively. The conclusions of technical
chapters are presented in the sections below.
13.2.1
The
existing DHSRs site will be released for housing and/or other compatible and
beneficial uses after implementation of the Project.
13.2.2
Subject
to subsequent planning, the released DHSRs and DHPS will provide opportunities
for enhancing the community with ample open spaces, a better connectivity to
existing housing estates and G/IC facilities and easy access to the natural
environment (e.g. Maclehose Trail Section 5, Lion Rock Country Park).
13.2.3
The
project location is rich in granite. Excavation of caverns will
produce a large amount of hard granitic rocks, which are valuable natural
resources for construction use. Rocks produced under this Project
would become a local source to support the construction industry.
Construction Phase
13.3.1
The
potential sources of air quality impacts associated with the construction of
the Project have been identified and the potential impacts were evaluated.
Fugitive dust may arise from the construction activities such as site
clearance, rock drilling, blasting operation, breaking works, excavation works,
handling and transportation of C&D materials, stockpiling and wind erosion.
With the implementation of mitigation measures recommended, no unacceptable
fugitive dust impact is expected during construction phase.
Operation Phase
13.3.2
As the
DHSRs and DHPS are mainly for the storage and pumping of fresh water and
flushing water, air quality impact during the operation of the Project is not envisaged.
Construction Phase
13.4.1
The use
of powered mechanical equipment during the construction phase of the Project is
expected to create noise impact to the nearby NSRs. Assessment indicates that
the construction noise impact can be largely mitigated to the criteria in the
EIAO-TM by use of quiet construction equipment, erecting noise barriers /
enclosures; implementing good site practices and use of quieter construction
method. With the implementation of the recommended mitigation measures, no
exceedance of the daytime construction noise criteria is expected.
Operation Phase
13.4.2
The
maximum permissible sound power levels for the ancillary facilities have been
derived as noise design target. With implementation of recommended mitigation measures,
fixed noise from operation of the Project will comply with the relevant noise
criteria.
Construction Phase
13.5.1
The potential sources of water quality
impacts associated with the construction of the Project have been identified and
the potential impacts were evaluated. Water quality impact may arise from
construction site run-off, general construction activities, sewage from
construction workforce, potential accidental chemical spillage, construction works in close proximity of inland watercourses, cleansing
effluent generated from washing of interior of structures and potential groundwater filtration. With proper implementation of
mitigation measures recommended, no unacceptable water quality impact is
expected during construction phase. Regular site inspection should be conducted during the construction
phase to ensure the recommended mitigation measures are properly implemented.
Operation Phase
13.5.2
The DHSRs
and associated pumping stations are mainly for the storage and pumping of fresh
water and flushing water, potential sources of water quality impact
include effluents from cleaning of service reservoir, non-point source surface
run-off from new impervious area and minimal sewage from the development. With
proper implementation of mitigation measures recommended, no adverse waste
quality impact is envisaged during operation of the Project..
Construction Phase
13.6.1
C&D materials will inevitably be produced
during the construction phase of the Project. Waste generated during
construction works include inert C&D materials, non-inert C&D
materials, chemical waste and general refuse. Provided that there is strict
control of C&D materials generated from construction works and that all
arisings are stored, handled, transported and disposed of in accordance with
the recommended mitigation measures, no unacceptable impact due to waste
management is expected during construction phase. The recommended mitigation
measures can be enforced by incorporating them into the waste management
requirements as part of the Environmental Management Plan. Environmental audit
would be necessary to ensure the implementation of proper waste management
practices during construction.
Operation Phase
13.6.2
With the implementation of the mitigation
measures during the operation phases of the Project, no significant impact on
waste management is anticipated.
13.7
Land Contamination
13.7.1
A review of past and present land uses of the
project site was conducted. Based on desk-top review and site walkover, the
presence of contaminated land is not expected.
13.8.1
Ecological impact assessment for the
relocation of DHSR has been conducted following the guidelines of the EIAO-TM
Annex 8 and Annex 16.
13.8.2
All total of 5 types of habitat were
identified within the study area, of which 2 types of habitats, including
plantation and developed area were located within the Project Area, where the
construction of ancillary building and associated water main laying works. The ecological
value of the identified habitats within the Project Area is rated low.
13.8.3
The proposed
works would not encroach into the boundary of Lion Rock Country Park, hence no
direct impact on wildlife and habitats within the country park is anticipated.
Direct and indirect ecological impacts that would arise from the Project during
the construction and operation phase have been identified and evaluated. Direct
impacts arising from the proposed works for the preferred tunnel portal and
cavern option include permanent loss of plantation (approx. 0.252 ha) and developed
area (0.032 ha), and temporary loss of plantation (approx. 0.760 ha) and
developed area (approx. 3.114 ha) are anticipated.
13.8.4
Construction
site runoff and other disturbance impacts resulting from the proposed
aboveground works may potentially have indirect impact on wildlife and species
of conservation interest. Standard mitigation measures such as good site
practice, control of lighting and minimization of groundwater infiltration are
proposed.
13.8.5
Most impacts
are considered to be negligible in nature. Overall, no significant ecological
impacts were anticipated in this assessment. With effective implementation of
recommended mitigation measures, no adverse residual ecological impacts are
expected from the Project.
13.9.1
The Project will inevitably result in some
landscape and visual impacts during construction and operation
phases. These impacts have been minimised through careful
consideration of alternatives, minimisation of works areas, and incorporation
of aesthetic external designs and landscape treatments of proposed aboveground
structures.
Broad Bush Tree
Survey
13.9.2
Based on a broad-brush estimate,
approximately 260-300 nos. of existing trees is directly overlapped with the proposed tunnel portal
and ancillary building, so trees would be unavoidably removed. The dominant
tree species are Acacia confusa, Sterculia lanceolate and Mallotus
paniculatus, No tree of particular interest was identified
within the Project site.
Landscape
Impact for Tunnel Portal, Ancillary Building and Access Road
13.9.3
The affected LRs and LCAs include LR1.2 Engineered Slope (Vegetated),
LR1.5 Lion Rock Park Transit Nursery and LCA2 Upland Hillside Landscape at Lion
Rock which falls within the footprints of the proposed tunnel portal, the
access road leading to the portal, and the ancillary buildings. The landscape
impacts of LRs and LCAs within the footprint of the tunnel portal, ancillary
facilities and temporary construction storage are considered to be Moderately Adverse without
implementation of mitigation measures during construction and operation phases.
Landscape Impact for Water Mains Works
13.9.4
The overall landscape impacts of LRs and LCAs along the footprint of the
proposed water mains (i.e. LR1.1 Roadside vegetation, LR2.1 Urban development, LR3.1 Tsz Wan Shan Road Sitting Out Area
and LCA4 Wong Tai Sin Residential Urban Landscape) are considered to be Slightly Adverse without implementation
of mitigation measures during construction phase and Slightly Adverse to Insubstantial during operation phase.
The remaining LRs and LCAs are far away from the Project Site and are estimated
to encounter Insubstantial landscape
impacts.
Visual Impact
for Tunnel Portal, Ancillary Building and Access Road
13.9.5
During the construction phase of the Project,
the overall visual impacts on the VSRs who can partially see the construction
site of the proposed portal and the ancillary buildings (i.e. residents of Tin
Ma Court (R01) and the Palace (R02)) are considered to be Moderately Adverse, and Slightly Adverse visual impact
on the another three VSRs (the recreational users in Lion Rock Park (L03),
Occupants in Lion Rock Park Transit Nursery (F07) and travellers along Lion
Rock Road (T02)) who can have a glimpse view of the construction site of the
proposed portal/ ancillary buildings without implementation of
mitigation measures.
13.9.6
During the operation, the Project will result
in Moderately Adverse visual impacts on the residents of Tin Ma Court
(R01) and the Palace (R02), and Slightly Adverse impacts on the other three
VSRs (L03, F07 and T02) who can glimpse
the portal site and the ancillary buildings.
Visual Impact
for Water Mains Works
13.9.7
The proposed water mains laying works will
only result in Slightly Adverse visual impacts on the local VSRs during
the construction phase. The rest of the VSRs who can see the temporary road
works for water mains laying works will only experience Insubstantial visual impacts during the Project operation phase as
the water mains are located in the underground and invisible to the VSRs.
Overall
Landscape and Visual Impacts
13.9.8
Tree compensation according to DEVB TCW No.4/2020 will be carried out. Trees will be compensated at a ratio of not less
than 1:1 in terms of quantity of removed trees. Tree species selected shall be
compatible with surrounding existing vegetation. It is considered that there is
no net loss of landscape resources in terms of trees upon full implementation
of compensatory planting. Given the above-ground works extent is rather small
in scale, the landscape resources in terms of areas might even encompass a
potential gain with full implementation of mitigation measures.
13.9.9
With full implementation of all proposed mitigation
measures, the residual impacts on all VSRs are anticipated to be Slight to
Moderate to Slight during construction phase and Slightly Adverse
to Insubstantial during operation phase. All the residual landscape and
visual impacts arising from the project are considered Acceptable.
13.9.10
As a whole, the residual landscape and visual
impacts of the proposed Project is considered acceptable with the proposed
mitigation measures implemented during construction and operation phases.
13.10.1
There will be no overnight storage of
explosives for this Project. Transportation of explosives to site for cavern
and tunnel construction will be undertaken on a daily basis. The contractor is
required to destroy any unused explosives before nightfall.
13.11.1
The EIA has identified and assessed the
potential environmental impacts during the construction and operation of the
Project in accordance with the requirements set out in the EIA Study Brief
(ESB-317/2019), EIAO-TM and all environmental legislation and standards. The
EIA has concluded that with the implementation of the recommended mitigation
measures, no unacceptable environmental impacts are envisaged as a result of
the construction and operation of the Project and the Project would be in
compliance with the applicable environmental legislation and standards.
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