15.1.1.1
The Project covers the following designated
project (DP) elements of Schedule 2, Part I under the Environmental Impact
Assessment Ordinance (EIAO) (Cap.499) -
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Item I.1(b)(ii) –
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A drainage channel or river training and diversion works which
discharges or discharge into an area which is less than 300m from the nearest
boundary of an existing or planned site of cultural heritage.
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15.1.1.2
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 at this stage. The assessment
has been conducted, in accordance with the EIA Study Brief No. ESB-319/2019
issued under the EIAO for the Project and the EIAO-TM, covering the following
environmental issues.
·
Air Quality Impact
·
Noise Impact
·
Water Quality Impact
·
Waste Management Implication
·
Land Contamination
·
Sewerage and Sewage Treatment Implications
·
Ecological Impact (Terrestrial and Marine)
·
Fisheries Impact
·
Cultural Heritage Impact
·
Landscape and Visual Impacts
15.1.1.3
The findings of this EIA Study have determined
the likely nature and extent of environmental impacts predicted 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 comply with the relevant environmental legislation and
standards during both the construction and operation phases. An environmental monitoring and audit
(EM&A) programme has also been developed.
The Implementation Schedules listing the recommended mitigation measures
are presented in Section 14. A
summary of key assessment assumptions and limitation of methodologies are
presented in Appendix 15.1.
15.1.1.4
A summary of the environmental outcomes/benefits
that have accrued from the environmental considerations and analysis during the
EIA study and the implementation of environmental control measures of the
Project are presented in the sections below.
15.2.1
Estimated Populations and Environmentally
Sensitive Areas Protected from Various Environmental Impacts
15.2.1.1
With the implementation of the Project, besides
improving the existing drainage facilities, over 20,000 m2 of
concrete-lined channel space would be transformed into green spaces to promote
greening of the local environment and the ecological value of existing FTN
would be enhanced with the incorporation of the ecological enhancement
features. Furthermore, the introduction
of the DWFI system under the Project would eliminate the long-standing water
quality and odour issues associated with the polluted discharges to the nullah
which have been of public concerns as expressed by Sha Tin District Council
(STDC) and local stakeholders. While the
revitalised FTN will not be opened up for public access due to safety reasons,
the proposed revamp/provision of pavilion, viewing decks and amenity areas, and
beautification of existing walkway and public open space along the nullah
(including the reprovisioned Kwei Tei
Street Garden) would improve the riverside environment for public enjoyment of
the enhanced waterscape.
15.2.1.2
During construction, mitigation measures as recommended
in the EIA will be implemented to protect the identified sensitive receivers in
the vicinity of the Project, including Chun Yeung Estate and Kwai Tei
New Village at upstream FTN, other residential
dwellings and institutional use near mid-stream and downstream FTN, e.g. Fo Tan Village, Hong Kong Sports
Institute etc, as well as industrial buildings surrounding the upstream and
mid-stream section of FTN) from air quality and noise impacts.
15.2.1.3
With the
implementation of DWFI system under the Project to intercept and divert the
polluted discharges from drainage outlets along the nullah to the existing
sewerage system for treatment, the odour nuisance of FTN currently experienced
by these air sensitive receivers and general public visiting FTN would be improved
as a result of the operation of the Project.
15.2.2
Environmental Designs Recommended,
Environmentally Friendly Option Considered and Incorporated in the Preferred
Option
Water Quality Improvement and Water
Friendliness
15.2.2.1
Due to ageing drainage systems and possible
expedient connection made in the past, polluted discharges from the existing
drainage outlets along FTN are observed at present. Complaints and concerns from the public,
including Sha Tin District Council (STDC) and local stakeholders, on the long-standing
water quality and odour nuisance of the FTN were received. With the implementation of the proposed DWFI
system of the Project, the dry weather flows from the drainage outlets along
FTN will be intercepted and discharge to the existing sewerage system via
gravity mains for conveying to Shatin Sewage Treatment Works for
treatment. With the interception of the
polluted discharges, the water quality would be improved and odour nuisance to
the resident nearby would be alleviated.
Greening Enhancement
15.2.2.3
The existing concrete nullah bed from the
section south to Kwei Tei
Street down to the section with tidal influence near Fo
Tan MTR Station and embankment down to the confluence with Shing Mun River will
be resurfaced with layer of vegetation, which will enhance both the aesthetic
and ecological values of FTN. Greening
along the nullah bed and banksides such as provision of emergent wetland
planting, mangroves, climbing plants, tree and / or grasscrete etc, will be
provided. The existing mature trees
growing along the nullah banks will be retained, and additional tree planting
will be provided. The existing planters
will also be modified to beautify the footpath along FTN.
Ecological Enhancement
15.2.3
Key Environmental Problems Avoided and
Compensation Area Included
Avoidance of Natural Habitats
15.2.3.1
All identified natural watercourses are located
in the upper catchment of FTN. Except for the
downstream section of a natural watercourse (WSR4 / S1) flowing directly
into the concrete channel of Fo
Tan Nullah, all other identified natural watercourses (including WSR5 /
S2 at Man Hang and WSR6 / S3 along Wong Chuk Yeung Street) are located outside
of the Project site. The natural
watercourse upstream of the concrete channel of FTN
that falls within the Project site has been avoided under the revitalisation
design that no works would be conducted within any natural watercourse.
Protection of Mature Vegetation
along FTN
15.2.3.2
There are existing mature trees along FTN on
pedestrian road within the Project site.
Although these tree species are not of conservation importance, the tree
specimens are mature with good foliage and tree crown that can potentially provide
habitat for fauna species. These mature
trees will therefore be retained under the revitalisation design.
Avoidance of Constructions Works
within Nullah during Wet Season
15.2.3.3
The construction work within the nullah,
including channel bed modification, construction of DWFI system along the
nullah, mid-stream submersible water pumps and waterpipe along the nullah and
desilting works at downstream tidal zone, will only be undertaken during dry season when
water is limited to low flow channel. In addition, site
demarcation and flow diversion as detailed in Section 5.8 will be implemented
to avoid release of sediments/other pollutants into receiving waters.
Minimisation of Construction
Disturbances
15.2.3.4
The Project site will be divided into six
sections to be constructed in sequence starting from downstream FTN and the
construction works within each section will be undertaken by parts to reduce
the construction impacts on nearby sensitive receivers as compared to
constructing simultaneously in adjoining sections and areas. Construction works outside the nullah such as
walkway improvement will be scheduled to avoid overlapping with works within
the nullah to avoid heavy construction activities concentrating in a certain
area over any period.
15.2.3.5
As the Project would not cause any loss of
habitat of conservation importance, no compensation area is recommended.
15.2.4
Environmental Benefits of Environmental
Protection Measures Recommended
15.2.4.1
Environmental benefits of environmental
protection measures recommended in this EIA Report are summarised below. No environmental disbenefits would be
envisaged from the proposed revitalisation works.
Air Quality Impact
15.2.4.1
The potential air quality impacts arising from
the construction of the Project would be related to fugitive dust emissions
from construction works and gaseous emissions from the use of PME, and odour
nuisance from
desilted / excavated materials generated during the
desilting at
downstream tidal zone /
excavation works in the nullah. In
view of the small scale of the Project, the air quality impacts would be
localised and minor, and would be well controlled through the implementation of
good site practices and dust suppression measures stipulated
in the Air Pollution
Control (Construction Dust) Regulation as well as the proposed good site
practices to minimise the
exhaust emissions from NRMMs and odour nuisance from handling of
desilting/excavated materials. Dust
monitoring for construction of the underground water storage tank at Kwei Tei Street Garden and
regular weekly site audit are recommended to be carried out during construction
phase in order to confirm that the mitigation measures are properly implemented
and are working effectively. No adverse air quality impact due to the construction of
the Project would therefore be anticipated.
15.2.4.2
With the implementation of DWFI system under the
Project to intercept and divert the polluted discharges from drainage outlets
along the nullah to the existing sewerage system for treatment, the odour
nuisance of FTN would be alleviated as a result of the operation of the
Project. Any odour emission generated
from exposed desilted materials during the routine maintenance works would be
temporary and confined to the areas of maintenance works that it would be
well-controlled through good site practices.
No adverse air quality impact due to the operation of the Project would
be anticipated.
Noise Impact
15.2.4.3
Noise impact would arise from the use of powered
mechanical equipment during construction phase.
With the proper implementation of the recommended mitigation measures
such as use of quality powered mechanical equipment (PME) / quieter
construction method and movable noise barriers, implementation of good site
practice and careful planning of concurrent use of noisy PME, the mitigated
cumulative noise levels at all NSRs would comply with the noise criteria set
out in the EIAO-TM. No adverse noise
impact is anticipated during the construction phase of the Project.
15.2.4.4
During operational phase, fixed plant noise from
the operation of the proposed submersible water pumps
installed under the nullah bed at mid-stream of FTN for ecological enhancement
associated water supplement would be the major source of noise impacts
based on the current design. The noise impact associated with the operation of
the Project has been assessed based on the design information provided by the
Project Engineer at the time of the assessment.
The assessment result indicated that the predicted fixed plant noise
levels at all representative NSRs would comply with the noise criteria. No adverse noise impact would be anticipated
during operational phase of the Project.
Commissioning test should be conducted prior to operation of the Project
to ensure that the fixed plant noise impact would comply with the relevant
noise standards.
Water Quality Impact
15.2.4.5
The key issues of the land-based construction
works include construction works at and in close proximity to FTN / inland
water, wastewater generated from general construction activities, construction
site runoff, sewage from construction workforce and accidental spillage of
chemicals. The potential water quality
impacts could be avoided and minimised by implementing the recommended
pollution control measures. No adverse
water quality impact during construction phase would be anticipated. Regular site audit should be undertaken
routinely to inspect the construction activities and works area to ensure the
recommended measures are properly implemented.
Waste Management Implications
15.2.4.7
During construction phase, waste types generated
from the Project are likely to include C&D materials from construction
activities, chemical wastes from maintenance and
servicing of construction plants and vehicles, desilted
materials from desilting works at downstream tidal zone, and general refuse
from workforce. Asbestos
containing materials would also be potentially generated from the demolition of
an asbestos cement pipe, which extent and location are still under
investigation, is identified along the low flow channel in FTN. In view of the nature and limited scale of
the Project, the quantity of waste arisings would not be substantial. However, improper handling, collection,
transportation and re-use / disposal of the wastes would likely give rise to
hygiene problems and adverse environmental impacts, e.g. odour nuisance to
local residents, and contamination of the nearby watercourses. Provided that these wastes are handled,
transported and disposed of according to the recommended good site practices
and measures, no adverse environmental impacts (including potential hazard, air
and odour emissions, noise and wastewater discharges) would be anticipated
during the construction phase.
15.2.4.8
The main waste types generated from the
operation of the Project would be silt, debris, screening and limit amount of
chemical waste from the routine maintenance of the DWFI system and nullah as
well as desilted
materials from maintenance desilting works. The maintenance practices would be similar to
the existing maintenance works undertaken by the DSD. With implementation of the good waste management practices, adverse environmental
impacts (including potential hazard, air and odour emissions, noise and
wastewater discharges) and public transport impact would not be anticipated
during operational phase. General refuse
would also be generated from the users of the revamped public open space along
FTN. Provided that sufficient number of
trash bins and recycling bins have already been provided and would be retained
for the collection of general refuse generated by pedestrians / users along
FTN, no unacceptable environmental impact and public transport impact would be
anticipated.
Land Contamination
15.2.4.9
Based on the findings of the site appraisal, no
adverse land contamination impact arising from Project is anticipated. No further site investigation works at the
Project site is required. Thus, no
Contamination Assessment Plan / Contamination Assessment Report / Remediation
Assessment Plan are required.
Sewerage and Sewage Treatment Implications
15.2.4.10
A DWFI system is proposed to improve the water
quality in the FTN with intercepted dry weather flow estimated to be at 2,700
m3/day. The sewage impact assessment
indicated that existing sewerage system has sufficient capacity to take up the
additional dry weather flow intercepted by the DWFI system. Thus, no mitigation measures are required.
Ecological Impact (Terrestrial and Marine)
15.2.4.12
Marine habitats within the assessment area
included subtidal hard substrata, soft bottom, and intertidal habitats, which
are all of low ecological value. As the
Project Area is located far from marine habitats (>2.6 km), no direct
impacts to marine habitats are anticipated, and indirect impacts are considered
negligible.
15.2.4.13
No direct impacts to natural habitats within the
assessment area are anticipated for the Project. Although natural watercourse was identified
within the Project Area, direct impact on the natural habitat is avoided
through confinement of construction works within boundary of the highly disturbed
habitats of developed area and modified watercourse only. Direct impacts arising from the proposed
works would be limited to the temporary loss (about 7.17 ha) of some modified
watercourse and developed area. Given
the relatively low to moderate ecological values of affected habitats, the small
area affected, and the temporary nature of the impact, direct impacts are
expected to be Minor. All affected areas
will be reinstated and enhanced in terms of ecological value as part of the
Project. Avoidance measures (e.g. protection of mature trees along the nullah
and avoidance of encroachment of natural watercourse) would be implemented to
preserve the day roosting habitats for bats and ardeids.
15.2.4.14
Indirect impacts during the construction phase
would comprise of human disturbance, construction noise, dust and site
run-off. With proper implementation of
the recommended mitigation measures and good site practices, no significant
adverse ecological impact is anticipated.
With ecological enhancement measures incorporated into revitalisation
design of FTN, nature of disturbance during operation phase would be minimal
compared to existing baseline condition.
Net positive ecological outcome would be resulted from the created and
enhanced wetland habitats. No
unacceptable adverse residual impacts would therefore be expected during both
construction and operation phase.
Fisheries Impact
15.2.4.15
The Project would only involve construction
works within the Project area (existing FTN and developed area alongside). No loss of fishing grounds and mariculture
areas are anticipated within the assessment area. With the implementation of the recommended
water pollution control measures, the Project would not cause any unacceptable
indirect impacts to fishing grounds and mariculture areas on fisheries within
the assessment area during both construction and operational phases.
Cultural Heritage Impact
15.2.4.16
A Declared Monument, Old House, Wong Uk Village, is located within 300m of the
discharge area from the revitalised FTN and located at about 900m from the
nearest site boundary. As the proposed
works are mostly situated within the FTN and there is substantial separation
distance between the Old House and the proposed works, no direct and indirect
impacts on the Old House are anticipated during the construction and operation
phases of the Project.
15.2.4.17
No built heritage resource or Site of
Archaeological Interest (SAI) were identified within 300 m from the Project
site and no archaeological potential was identified within the Project area, no
impact to built heritage or archaeology would be
anticipated.
Landscape and Visual Impacts
15.2.4.1
During construction phase, the proposed
channel modification and construction of DWFI system and mid-stream water pumps
for ecological enhancement associated water supplement will be constructed
inside the existing Fo Tan Nullah, while some
proposed architectural structures will be constructed at the roadside for
enhancement of public open space which may impose visual impact to adjacent
VSRs. Based on the broad-brush tree
survey, amongst the 173 nos. of surveyed trees, 133 nos. are proposed to be
retained, including all existing mature trees growing along the nullah
banks. A total of 25 nos. of trees are
proposed to be removed, all of which are common species including Acacia confusa, Bauhinia variegata, Bischofia javanica, Melia azedarach
and Morus alba, and including 15 nos. of undesirable species, Leucaena
leucocephala; and a total of 15 nos. of trees are
proposed to be transplanted, species including Bauhinia variegata,
Bischofia javanica,
Lagerstroemia speciosa and Magnolia grandiflora.
As stipulated in DEVB
TC(W) No. 4/2020, “…the number of compensatory trees onsite and offsite shall
not be lower than that of number of trees removed including dead trees, but
excluding trees of undesirable species...”, therefore
to compensate the loss of existing trees, approximately 10 nos. of heavy
standard compensatory trees are proposed in available planting area to enhance
the amenity value to vicinity of site. With
proper implementation of mitigation measures, all affected LRs and LCAs would
have “moderate” to “insignificant” adverse landscape impacts whilst all
affected VSRs would have “slight” or “insubstantial” adverse visual impacts
except for REC3 which would have “moderate” adverse impacts during construction
phase.
15.2.4.2
Fo Tan Nullah will be
revitalised with architectural and landscape features aimed at promoting water
friendliness and providing an enhanced green and ecological environment. The proposed architectural and landscape features
and modified channel bed would be the key sources of visual and landscape
changes during operation. With proper
implementation of landscape and visual measures, namely greening enhancement
along channel bed and embankment, provision of recreational opportunity along
nullah, sensitive and aesthetically pleasing design, re-provision of affected
open space, all affected VSRs will have “insubstantial” adverse visual impacts
except for REC3 which has “slight” adverse impacts at Day 1 of operational
phase. All VSRs would have “insubstantial”
or no adverse impact at Year 10 of operational phase. In conclusion, the landscape and visual
impacts are considered as acceptable in accordance to Annexes 10, 11 and 18 of
the EIAO-TM.
15.3
Summary of Key Environmental Impacts
15.3.1.1
A summary of environmental impacts for the
environmental issues in this EIA is presented in Appendix 15.2.
15.4.1.1
A summary of alternative development options and
environmental benefits and disbenefits of different mitigation options is
presented in Section 2.4.
15.5.1.1
The findings of this EIA have provided
information on the nature and extent of environmental impacts arising from the
construction and operation of the Project.
The EIA has, where appropriate, identified mitigation measures to ensure
compliance with the relevant environmental legislation and standards.
15.5.1.2
Overall, the EIA Report has predicted that the Project
would be environmentally acceptable with the implementation of the proposed
mitigation measures for the construction and operational phases. An environmental monitoring and audit
programme has been recommended to ensure the effectiveness of recommended
mitigation measures.