·
Air Quality Impact
·
Noise Impact
·
Water Quality Impact
·
Waste Management
·
Terrestrial
Ecological Impact
·
Landscape and Visual
Impacts
·
Cultural Heritage
Impact
·
Land Contamination
·
Hazard to Life
|
The
Project Need |
·
Aging
of plant and equipment after more than 40 years of service requiring major
renovation or replacement; and ·
Reprovision of the South Works of
the existing Sha Tin WTW with a treatment process
that can continue to meet the latest treated water quality standards. |
|
Environmental/Social Benefits of the Project |
·
Provision
of a safe and reliable water supply; ·
Improvement
in water supply reliability to the territory; ·
Development
of environmentally sustainable design by applying low-carbon concept; ·
Provision
of education facilities to the general public. |
|
Environmentally
Friendly Design and Benefit |
·
In-situ
reprovisioning of the WTW promotes re-use of land, thereby minimising the
environmental impacts and costs of developing a new site; ·
About
90% of the works area is situated within the existing Sha
Tin WTW is of low ecological value.
The impact to natural habitat is minimized. ·
Impacts
to ecological sensitive areas have been minimized through the design process
(e.g. use of retaining wall instead of soil nails); ·
The
adoption of new treatment processes will reduce the use of chlorine, which
presents a significant health risk to adjacent communities; ·
Engineering
design for fixed plant complies with the day-time, evening time and night
time noise criteria; ·
Lighting/glare ·
Green
roof, sensitive landscaping, other sustainability features. ·
Due
to the introduction of the new treatment technologies, the reprovisioning
works will lead to a permanent reduction in chlorine storage and usage at the
WTW. As a result, the chlorine-related risks for the surrounding population
will be reduced in comparison with current levels. |
|
Air
Quality |
Potential air quality
impacts from the construction works of the Project would mainly be related to
construction dust from excavation, materials handling, spoil removal,
demolition and wind erosion. In view
of the nature of works, adverse dust impact at the ASRs would not be expected
from the Project. Nevertheless,
appropriate dust suppression measures as stipulated in the Air Pollution
Control (Construction Dust) Regulation should be implemented to minimize any
potential dust impact. |
|
Noise
Impact |
Construction Noise This assessment has
presented the construction noise impacts of the Project during normal daytime
working hours. The predicted unmitigated noise levels at
representative NSRs would range from 46 to 78 dB(A). With the adoption of quiet PME and use of
movable noise barrier, the noise levels due to the Project itself at all
representative NSRs would comply with the EIAO-TM criteria. When considering the
cumulative construction noise impacts, exceedance
of 1
dB(A) during examination periods would be predicted
at C.U.H.K.F.A.A. Thomas Cheung School; however, the exceedances
are only contributed by the concurrent construction works of SCL(TAW-HUH) as
the Project does not induce any impact during that period. All practicable
direct mitigation measures have been exhaustively investigated and residual
impact is minimised. The residual
impacts are considered to be temporary, reversible and unlikely to induce
public health concern and as such, are considered to be minor and acceptable. Fixed Plant Noise The noise impact
associated with the operation of the Project has been assessed. The predicted fixed plant noise levels at
the representative NSRs would be expected to comply with the day-time,
evening time and night time criteria based on the assessment using a set of
specified maximum SWLs for the newly proposed fixed plant. If there is any change in engineering
design information during detailed design stage or fitting-out stage, the
fixed source noise design should be reviewed by the Engineer/Contractor to
ensure that both the NCO and EIAO-TM criteria at NSR can be met in the
future. |
|
Water
Quality |
Potential water quality
impact associated with land-based construction works for the Project would be
generated from site run-off, wastewater from construction activities, and
sewage from workforce. Provided that
all the recommended mitigation measures are properly implemented, no adverse
water quality impacts would be expected during the construction phase of the
Project. Water quality monitoring of the two water courses along the Project
boundary is recommended during site clearance and foundation works to ensure
no adverse water quality impacts to these water courses. Regular site
inspection is also recommended to ensure the recommended mitigation measures
are properly implemented. During operation phase of
the Project, major sources of water quality impact would be washwater effluent and overflow from treatment works
components. Proper mitigation measures will be implemented to avoid discharge
of washwater effluent and overflow into the nearby
water environment and hence no adverse water quality would be expected. |
|
Waste
Management |
Waste types generated by
the construction activities are likely to include inert and non-inert C&D
materials from demolition works of existing facilities of the South Works,
construction works of new facilities for the North and the South Works, slope
excavation works and construction works of new access roads, general refuse
from the workforce and chemical wastes from the maintenance of construction
vehicles and equipment. Provided that
these identified wastes would be handled, transported and disposed of using
the recommended methods and that good site practices would be strictly
followed, adverse environmental impacts are not expected. The waste management
assessment has recommended good waste management practices to ensure that
adverse environmental impacts are prevented.
The assessment concluded that no unacceptable environmental impacts
would result from the storage, handling, collection, transport and disposal
of wastes arising from the construction and operation of the project. |
|
Terrestrial
Ecology |
A literature review and
ecological field surveys have been conducted. Four habitat types were
identified within the study area including secondary woodland, plantation,
watercourse and developed area. The
secondary woodland habitat is considered to have high ecological value. The other habitat was regarded as of low
value. Six flora and 26 fauna species
of conservation importance were recorded from the study area during surveys. Major ecological impacts
would include direct impact on the secondary woodland habitat and the floral
species of conservation importance.
The impacts to about 0.69 ha of secondary woodland habitat would be
compensated by the creation of about 0.23 ha on-site of woodland habitat
within the Sha Tin WTW and about 0.29 ha off-site of woodland habitat at Sha Tin
South Freshwater Service Reservoir nearby and northwest of Sha Tin West Service Reservoir (a total of about 0.52 ha). The area of secondary woodland habitat
would be reduced by about 0.17ha.
Feasible woodland compensation locations have been exhaustively
investigated and residual impact is minimised as far as practicable.
Considering the size and value of the habitat affected, the residual impact
is considered to be insignificant, with the implementation of the recommended
habitat compensation. Four flora species of
conservation importance (Incense Tree, Ailanthus, Lamb of Tartary, and Hong Kong Eagle’s Claw) would be
directly affected by the Project.
Detailed vegetation surveys should be conducted to identify the
affected individuals within the proposed works area. Transplantation is recommended as far as
possible to minimize the direct impact to these important species. The implementation of a
mitigation strategy for Short-nosed Fruit Bat will avoid impacts to this
species, thereby resulting in no adverse impact. Indirect impacts during the construction
phase would comprise noise and human disturbance, construction dust, and
construction site runoff. With proper
implementation of good site practices and noise mitigation measures, no
significant adverse ecological impact is anticipated. The level of disturbance
during the operation phase would be comparable to the existing
condition. No significant adverse
impact is therefore expected. With the implementation
of the recommended mitigation measures, no unacceptable residual indirect
impact due to the construction and operation of the proposed Project would be
expected. The implementation of
mitigation measures would be subject to regular audit as part of the EM&A
programme. |
|
Landscape
and Visual |
The proposed works of the
Project at Sha Tin WTW would inevitably result in
some landscape and visual impacts during the construction and operation
phases. These impacts have been
minimized through careful consideration of alternatives, minimization of
works areas, incorporation of aesthetic external
designs and landscape treatments of proposed structures. The proposed works will
be mainly located within the existing Sha Tin WTW
Compound under the Other Specified Uses (OU) of the Approved Sha Tin Outline Zoning Plan No. S/ST/30. It is considered that the proposed Project
is permitted development under the OZP and would fit in with the current and
future planning settings and would not be in conflict with the statutory town
plan. Based on a preliminary
tree survey, approximately 800 existing trees will be affected by the
proposed works. Among these 800 trees,
approximately 652
trees will be felled due to the Project. None of these are Registered Old and
Valuable Trees. There are approximately 21 nos. of Aquilaria sinensis which is protected under Cap.
586 in Hong Kong and 1 no. of Ailanthus
fordii under the Forest and Countryside
Ordinance (Cap. 96). Any affected Aquilaria sinensis and Ailanthus
fordii including other trees of conservation
importance are proposed to be transplanted where possible. Detailed tree survey and removal
application will be submitted in accordance with DEVB TCW No. 10/2013 - Tree
Preservation separately. Under the
proposed scheme for the Project, opportunities for tree compensation within
the project boundary have been fully explored and incorporated in the
proposed mitigation measures as much as practicable. Due to limited available space for tree
planting within the project boundary, approximately 200 nos. of heavy
standard trees and 460 nos. of light standard trees are proposed on-site and
off-site at Sha Tin South Freshwater Service
Reservoir and Sha Tin West Service Reservoir at Po Fook Shan to compensate for the tree to be felled. It offers a compensation ratio greater than
1:1 (i.e. approximately 660 newly planted trees v.s.
approximately 652
felled trees). Approximately 2,300m2
of woodland mix planting are proposed on-site whereas about 2,900m2
off-site to compensate for the impact to the woodland habitat. There would be substantial
residual landscape impact on LR1 and moderate residual landscape impact on
LR2, LR3, LR4 and LCA2 with the implementation of proposed mitigation
measures during construction phase. The residual impact of LR1 would be moderate and LR2, LR3, LR4 and
LCA2 would be slight in Day 1 operation phase and reduced to slight and
insubstantial in Year 10 of operation phase when the proposed compensatory
planting including woodland mix planting becomes mature. Because not all woodland/tree compensation will be
provided on-site, some of the woodland/tree planting will be
compensated off-site. There would
still be some slight residual impact on LR1. There would be moderate
residual visual impact on VSRs R1, R2, R3, R4, GIC1, O1 and O2 and slight
residual impact on VSRs T1 and T2 during the construction phase. The residual impact would be slight in Day
1 of Operation Phase and reduced to insubstantial in Year 10 of Operation
Phase. Although there is slight
residual impact on LR1, as a whole, it is considered that the residual
landscape and visual impacts of the proposed project is considered acceptable
with mitigation measures implemented during construction and operation
phases. |
|
Cultural
Heritage |
Cultural heritage
resources within the study area have been identified and reviewed through site
surveys and literature review. No
archaeological potential is present within the study area. Therefore no impact to archaeology is
anticipated. Direct impact on three existing graded historic buildings at Hin Tin
village and the Ex KCR Beacon Hill Tunnel during construction phase is not
anticipated.
Considering sufficient buffer
distances between the built heritages at Hin Tin village (approximately 270
m) and the proposed works areas, there would be insignificant visual and vibration impact during construction and operation phases. Four existing staff quarters would be refurbished
to be used as construction site office located in close proximity to the west
of Ex KCR Beacon Hill Tunnel portal, and the proposed Administration Building
cum Mainland East Laboratory would also be built at about 120 m to the northwest of the portal. Due to the
proposed work design and distance between these buildings and the tunnel
portal, vibration impact on the facade wall of portal is considered to be
insignificant. As precautionary
measure, ppv limit of 7.5mm/s is recommended,
including measuring at the facade wall of tunnel portal and
inside the tunnel where it is nearest
to any construction works within the Works Area. In
conclusion, the construction and operation of the Project would not cause
unacceptable impacts on cultural heritage resources, with implementation of
the recommended mitigation measures. |
|
Land
Contamination |
This assessment has
examined the potential contaminating land uses within the Project site. It
also covers potential impacts of the contamination on future use. The assessment involved site appraisal and
preparation of CAP. Site investigation will
be carried out at the decommission stage of the Project site due to site
access and sensitive nature of the water works. Based on the findings in the site
investigation, if any contamination is found, appropriate remediation
measures shall be identified and carried out before construction commences,
so as to clean up the Project site to the relevant RBRGs. With the
remediation and mitigation measures in place, the potential land
contamination impacts to the sensitive receptors and future use as water
treatment facilities are thus not considered to be insurmountable. As a
precaution, mitigation measures are proposed for the excavation of soil,
treatment of soil and general environmental, health and safety on site during
the construction stage. |
|
Hazard to Life |
A
Hazard Assessment of the risks associated with the transport, storage and use
of chlorine at Sha Tin WTW and off-site transport
of chlorine within the Consultation Zone has been conducted for the
Construction and Operational Phases of the Project. To obtain the total
chlorine risks, risks from the on-site Sha Tin WTW
chlorine transport, storage and use were combined with the off-site chlorine
transport risks. The
Sha Tin WTW Reprovisioning is an improvement
project. Due to the introduction of the new treatment technologies, the
reprovisioning works will lead to a permanent reduction in chlorine storage
and usage at the WTW. As a result, the chlorine-related risks for the
surrounding population will be reduced in comparison with current levels. The
assessment results show that for both Construction and Operational Phases,
the Individual Risk complies with the Hong Kong Risk Guidelines. The
Societal Risk lies within the As Low As Reasonably Practicable (ALARP) region
of the Hong Kong Risk Guideline (HKRG). An ALARP assessment has been carried
out to identify feasible mitigation measures and assess the cost
effectiveness of each measure in terms of risk reduction achieved and the
cost of implementing the measures, a number of recommendations have been
made. The residual risks remain in the ALARP region. Cumulative
Individual Risks within the Consultation zone were also presented by
combining risks from the on-site transport, storage and use of chlorine,
off-site chlorine transport, Beacon Hill North Offtake
Station, the 750mm and 500mm gas pipelines that run through the Old Beacon
Hill Tunnel, and the explosives transport and use for SCL construction. The
cumulative Individual Risk values are low and in the maximum order of 10-6
per year which complies with the Hong Kong Risk Guidelines. The
Cumulative Societal Risk lies within the “ALARP” region of the Hong Kong Risk
Guidelines. |
~ End of
Section 14 ~