15.
Conclusion
15.1
General
15.1.1.1
This Environmental Impact
Assessment (EIA) Report has been prepared for Tuen Mun Bypass (the Project) in accordance
with the requirements given in the EIA Study Brief (SB) (No.: ESB-348/2021) and
the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).
Environmental assessment of the potential environmental impacts associated with
the construction and operation of the Project has been conducted. Environmental
issues covered in this EIA include:
·
Air quality impact;
·
Noise impacts
·
Water quality impact;
·
Waste management implication;
·
Land contamination;
·
Hazard to life;
·
Landfill gas hazard;
·
Ecological impact (terrestrial);
·
Landscape and visual; and
·
Impact on cultural heritage.
15.1.1.2
This section summaries the
assessment results of each technical aspect and concludes the acceptability of
the overall environmental performance of the Project.
15.1.1.3
The key assessment assumption,
limitation of assessment methodologies and all related approach on assessment
of different environmental aspects requiring agreements with Environmental
Protection Department (EPD) are given in Appendix 15.1.
15.1.1.4
A summary of environmental
impacts identified in this EIA is provided in Appendix 15.2 and the conclusion of each technical aspect are
described in the following sections.
15.2
Air Quality
15.2.1
Construction Phase
15.2.1.1
The air quality assessment
studies the potential air quality impacts on Air Sensitive Receivers (ASRs) due
to the construction and operation of the Project.
15.2.1.2
Potential construction dust
impact would be generated from site clearance, soil excavation, backfilling,
construction of tunnels, blasting works, barging facilities
and construction vessels, etc. during construction phase of the Project. A
comprehensive review has been conducted on the monitoring data for similar
infrastructure projects and the construction dust impact assessment indicate
that given the implementation of good site practices and mitigation measures,
such as regular watering, implementation of vehicle washing facilities at the
construction site exits, tunnel blasting in a fully enclosed environment, and
cages or mats, etc., adverse air quality impact during construction phase is
not anticipated. Nevertheless, continuous dust monitoring is also proposed at
comprehensive locations (i.e., closest ASRs in all directions) to ensure that
there is no adverse dust impact on the nearby ASRs, and action plan is also
proposed in case of exceedance of action and limit levels.
15.2.2
Operational Phase
15.3
Noise Impact
15.3.1.1
The noise assessment studies
the potential noise impacts on Noise Sensitive Receivers (NSRs) due to the
construction and operation of the Project.
15.3.2
Construction Noise
15.3.2.1
Potential construction noise impact would be generated from the use
of PME during construction phase of the Project. A review has been conducted on
the construction methodology, and it is considered that given the
implementation of good site practices and mitigation measures, such as quieter
construction method, quieter plant, silencer, movable noise barrier, noise
enclosure / barrier, etc., adverse construction noise impact during
construction phase is not anticipated.
15.3.2.2
Nevertheless, a Construction
Noise Management Plan (CNMP) containing a quantitative construction noise
impact assessment, the adopted quieter construction method(s) and equipment,
noise mitigation measures and the construction noise impact monitoring and
audit programme will be submitted to the EPD with reference to the updated and
identified plant inventories once available and in any case before tendering
and commencement of the project construction, and if there is any change to the
construction noise mitigation measures recommended in the CNMP, an updated CNMP
shall be submitted one month before the implementation of such change.
15.3.3
Road Traffic Noise
15.3.3.1
A quantitative road traffic
noise impact assessment has been conducted for planned, existing and committed
noise sensitive uses. No adverse road traffic noise impact due to the Project
is anticipated.
15.3.4
Fixed Noise Sources
15.3.4.1
Potential fixed noise source
impact would be generated from the ventilation shaft of ventilation buildings
and mechanical system of the administration building in administration area,
satellite control building and maintenance compound. A review has been
conducted on the design of these fixed noise sources and it is considered that
given the implementation of good design and mitigation measures, such as
quieter plant, silencer, barriers, enclosures, etc., adverse fixed noise source
impact during operational phase is not anticipated.
15.4
Water Quality Impact
15.4.1
Construction Phase
15.4.1.1
Potential water quality impact
due to construction works has been reviewed. The potential sources of water
quality impact during the construction phase are mainly from operation of
temporary barging point and land-based construction activities including construction
runoff, tunnelling and underground works, buildings construction, sewage from
the workforce, construction works in close proximity
of inland water, groundwater from contaminated areas and contaminated site
run-off, diversion of watercourses and accidental spillage. With the mitigation
measures such as Best Management Practices (BMPs) and water control strategies
during tunnelling and underground works, adverse impacts are not anticipated
during construction phase.
15.4.2
Operational Phase
15.4.2.1
During the operational phase of
the Project, the major sources of potential water quality impact include road
and tunnel runoff discharged from paved roads and developments proposed under
the Project including the sewage generated by the proposed satellite control
building and administration buildings, and wastewater generated from washing
and maintenance operations. However, with proper implementation of recommended
mitigation measures and best practices, adverse water quality impacts are not
anticipated during the operational phase of the Project.
15.5
Waste Management
Implications
15.5.1
Construction Phase
15.5.1.1
Potential waste management
implications from the generation of waste during the construction phase have
been evaluated. General mitigation
measures of good site practices, waste management measures and strategic mitigation
measures, including the opportunity for on-site sorting, reusing C&D
materials, etc., are devised to minimise the surplus materials to be
disposed. Recommendations have been made
for implementation by the Contractor during the construction period to minimise
waste generation and off-site disposal.
15.5.2
Operational Phase
15.5.2.1
The types of waste that would
be generated during the operation phase have also been assessed. Recommendations have been made to ensure
proper treatment and disposal of these wastes.
Appropriate waste collector would be employed to handle general refuse,
and chemical waste generated during operation phase respectively.
15.5.2.2
With the implementation of the
recommended waste management measures and good site practices, unacceptable
waste management implications would not be anticipated for construction and
operation phase.
15.6
Land Contamination
15.6.1.1
Site
appraisals, in the form of desktop review and site walkovers were conducted
under this EIA, to identify any current / historical potentially contaminating
and uses within the Project Area. Based on the findings of site appraisals, a
total of nine areas were identified with potential land contamination concerns
as documented in the Contamination Assessment Plan (CAP) prepared under this
EIA.
15.6.1.2
Site
investigation (SI), sampling and laboratory analysis plan, targeting the
potential contamination area and hotspots identified within the Assessment Area
is recommended in the CAP. Some potential contaminated area
were inaccessible during the time of preparation of the CAP. It was also
observed that all the potential contaminated area are in operation and
infeasible to conduct SI and sampling works during EIA stage. Therefore, prior
to the development of these areas, site re-appraisal of the whole Project Areas
should be carried out in order to address any new
contamination issues caused by the (i) changes in operation of the identified
potentially contaminated site and (ii) changes in land use within the Project
Area. The supplementary CAP(s), incorporating the findings of the site
re-appraisal and the updated sampling and testing strategy, should be prepared and submitted to EPD for agreement prior to the
commencement of SI works.
15.6.1.3
SI works shall then be
conducted according to the supplementary CAP(s). Upon the completion of SI works. Contamination
Assessment Report (CAR) shall be prepared and submitted
to EPD for agreement. If land contamination is identified based on the SI
results, a combined CAR- Remediation Action Plan (CAP-RAP) for formulating
necessary remedial measures shall also be submitted to the EPD for agreement. Any identified contaminated soil and
groundwater should be treated according to the RAP(s) to be approved by EPD and
Remediation Report(s) (RR(s)) should be submitted to EPD for agreement after
the completion of the remediation works. No development works at the
contaminated areas shall be commenced prior to EPD’s agreement of the RR(s).
15.6.1.4
With the implementation of the
recommended further works mentioned above, any soil/groundwater contamination
would be identified and properly treated prior to the construction works. No
insurmountable land contamination impacts to the Project are therefore
anticipated.
15.7
Hazard to Life
15.7.1
Construction Phase
15.7.1.1
The Project falls into consultation
zone of a Potentially Hazardous Installations (PHI) (i.e., ExxonMobil LPG
storage installation located at Tuen Mun Area 44. Nevertheless, the tunnel
alignment of the Project is located at more than 30m under this PHI. Also, the
tunnel alignment of the Project is located at 30m under the LPG storage
installation at Sam Shing Estate. Tunnelling using Tunnelling Boring Machine
(TBM) is adopted for constructing the tunnel section close to these LPG
installations, such that at-grade construction activities and any blasting
works in their vicinity have been avoided.
In addition, with
reference to monitoring of other similar project, no ground settlements would
be expected for these two LPG storage installations. Moreover, monitoring and mitigations measures would
be proposed to control the ground vibration or ground settlement induced by TMB
tunnelling. Hence, potential risk during
construction phase is not envisaged.
15.7.1.2
Drill-and-blast works are required for
the tunnel construction and some of the slope works. According to the latest
design, overnight storage of explosives on site is required. Three temporary
explosive magazines at Lam Tei, Siu Lam and Pillar Point have been proposed,
which would be share-used with Route 11.
15.7.1.3
A quantitative risk assessment
(QRA) has been conducted for the transportation, overnight and use of
explosives. The QRA has also considered other concurrent projects, such as
Route 11 and Lam Tei Underground Quarry, for the cumulative impacts. The assessment
results show that the societal risk for the overnight storage and transport of
explosives as well as the use of explosives lie within the “ALARP” region. For
individual risk, compliance is anticipated. For individual risk, compliance is
anticipated. A detailed ALARP assessment has been conducted. Mitigation
measures and best practices, such as provision of dedicated training programme
and implementation of emergency response and training, have been recommended to
minimize the risk even further.
15.7.1.4
A Hazard Management Plan would
be formulated with a view to aligning the understanding of the risk of the
three concurrent projects (Route 11, TMB and Lam Tei Underground Quarrying
(LTUQ)). The measures stipulated in the Hazard Management Plan shall include,
but not limited to, the adjustment of the blasting schedules of the three
projects to minimize the potential cumulative impact, provision of common
trainings and drills to the workforce of all the three projects, etc.
15.7.2
Operational Phase
15.7.2.1
The
Project falls into consultation zone of a PHI (i.e., ExxonMobil LPG storage
installation located at Tuen Mun Area 44). Also, the Project is located at some
distance from the LPG storage installation at Sam Shing Estate. However,
section of the Project in proximity of these LPG storage installations is in
form of tunnel, the
population induced from the tunnel is all located in a confined space underground and hence,
would not be affected by the hazardous events from these LPG storage
installations. Hence,
potential risk during operational phase is not envisaged.
15.8
Landfill Gas Hazard
15.8.1.1
A
qualitative assessment on potential hazards associated with landfill gas
migration from the Pillar Point Valley Landfill (PPVL) to the proposed Project
site has been carried out. PPVL is
considered as a “medium” source of gas migration due to the landfill condition
with the implementation of multiple landfill gas controls. The source-pathway-target analysis shows that
landfill gas risk posed by the PPVL to the Project is “medium” during
construction phase and “low to high” during operation phase.
15.8.1.2
In general, underground rooms or void
spaces should be avoided as far as practicable at the Administration Building, Maintenance Compound and
temporary re-provisioning of Electrical and Mechanical Services Department
(EMSD) Servicing Centre of the site within Consultation
Zone. Other precautionary and protection
measures during design, construction and operation phases of the Project have
been recommended for elements within the Consultation Zone. It is expected that with the proposed
precautionary measures in place, the potential risk of landfill gas migration
to the respective targets will be minimal.
15.9
Ecological Impact
(Terrestrial)
15.9.1.1
The ecological impact
assessment has been carried out based on findings from the literature reviews
and the field surveys of conducted for six months covering both wet and dry
seasons completed in 2022. According to the Project alignment, the Project will
cause potential permanent habitat loss to mixed woodland (~2.2 ha), plantation
(~3.1 ha), shrubland/grassland (~0.9 ha) and watercourse (~0.3 km).
15.9.1.2
Majority
of the identified impacts are considered to be low in
the absence of mitigation measures. However, the potential impact on direct
loss of mixed woodland and watercourses and direct ecological impact on flora
and fauna species of conservation importance as low to moderate. Necessary mitigation measures and ecological
monitoring programme were proposed.
15.9.1.3
It
is predicted that the impacts will mainly arise during the construction phase,
as no major activities would be conducted during the operation phase that would
affect the adjacent habitats.
15.9.1.4
Direct
impacts on aboveground habitats in sites of conservation importance such as Tai
Lam Country Park are avoided while potential indirect impacts and groundwater
drawdown resulting from the tunnelling works will be suitably mitigated and
monitored during both the construction and operational stages.
15.9.1.5
With the
implementation of proposed mitigation measures, adverse residual impacts from
the Project on the ecological resources within and in the vicinity of the
Project Area during construction and operation phases would not be anticipated.
The residual impact
of the loss is therefore considered to be minor and acceptable.
15.10
Landscape and Visual
Impacts
15.10.1.1
Potential landscape and visual impacts during construction and operation
phases have been minimized through careful consideration of alternatives to
minimize direct conflict with the Tai Lam Country Park, minimization of works
areas, and incorporation of aesthetic external designs and appropriate
landscape and visual treatments along the TMB.
15.10.1.2
A tree group survey has been
carried out to assess the general tree condition and to identify any Trees of
Particular Interest (TPIs) within and near the proposed limit of works. Among the estimated 6208 nos. of
existing trees (including an estimated 6207 nos. of trees in tree groups and 1
no. of TPI, excluding common undesirable species) within the tree survey boundary, 3083 nos. of existing trees would
be retained and protected. An estimated 342 nos. of affected trees, mostly recent plantings
associated with TMCLKL, are considered suitable for transplanting. An
estimated 2783 nos. of affected
trees (including 1 no. of TPI, namely
a Ficus elastica with DBH of over 1m, is recorded within EMSD Tuen
Mun Vehicle Servicing Station) would
be removed due to low “Suitability for Transplanting” as assessed at this stage. Since most of the affected
individual trees are located either on natural terrain or engineered slopes and
in mature size, their survival rate after transplanting is low and not feasible
for transplanting. In this connection, tree removal is proposed with
compensatory planting.
15.10.1.3
There is no Registered OVT within the proposed limit of works. Meanwhile, 1 no. of Tree of Particular Interest (TPI) would
inevitably be affected and proposed to be removed.
15.10.1.4
It is predicted that in year 10
of operation, there will be Slight adverse residual impacts after mitigation for LR-PP2 (Plantations in
Pillar Point), LR-PP4 (Shrublands in Pillar Point), LR-TM2 (Plantations in Tuen
Mun), LR-LT2 (Plantations in Lam Tei), LCA-TM2 (Tuen Mun Upland Fringe
Landscape) and LCA-LT4 (Lam Tei Upland Landscape).
15.10.1.5
It is predicted that in year 10
of operation there would be Insubstantial residual impact on: LR-PP10 (Seawater Body in Pillar Point),
LR-PP11 (Developed Area in Pillar Point), LR-TM1 (Secondary Woodland in Tuen
Mun), LR-TM11 (Developed Area in Tuen Mun), LR-TM13 (Playground in Wah Fat
Street), LR-LT1 (Secondary Woodlands in Lam Tei), LR-LT7 (Watercourses in Lam
Tei), LR-LT11 (Developed Area in Lam Tei), LR-NL2 (Plantations in
Northern Landfall), LR-NL10 (Seawater Body at Northern Landfall), LR-NL11
(Developed Area in Northern Landfall), LCA-PP2
(Pillar Point Upland Fringe Landscape), LCA-PP10 (Lung Mun Road Highway
Corridor Landscape), LCA-PP12 (Pillar Point Mixed Modern Institutional Urban
Landscape), LCA-PP13 (Pillar Point Mixed Modern Industrial Urban Landscape),
LCA-TM4 (Tuen Mun Upland Landscape), LCA-TM11 (Tuen Mun Residential Urban
Landscape), LCA-LT2 (Lam Tei Upland Fringe Landscape), LCA-LT3 (Lam Tei Rural Landscape),
LCA-NL8 (Northern Landfall Maritime Landscape), LCA-NL10 (Northern Landfall
Highway Corridor Landscape) and LCA-NL13 (Northern Landfall Mixed Modern
Industrial Urban Landscape).
15.10.1.6 There would be Slight
adverse residual visual impacts in Year 10 of the operational phase after
mitigation for VSR-TM1 (Residents of Alpine Garden, Rainbow Garden, Kam Fai
Garden, Harvest Garden and Hoi Tak Garden), VSR-TM9 (Recreational Users of Wah
Fat Garden), VSR-TM10 (Travelers of Wah Fat Street), and VSR-PP1 (Vehicle
Travelers at Lung Mun Road).
15.10.1.7 The remaining VSRs will be subject to an Insubstantial residual impact in Year 10 of the operational phase
after mitigation, namely, VSR-TM2 (Residents of Seaview Garden), VSR-TM3
(Residents of Pearl Island Garden), VSR-TM4 (Visitors at Tuen Mun Promenade),
VSR-TM5 (Visitors at Hong Kong Gold Coast Dolphin Square), VSR-TM6 (Maritime
Travelers to / from Tuen Mun Ferry Terminal), VSR-TM7 (Vehicle Travelers at
Tuen Mun Road), VSR-TM8 (Recreational Users of Tsing Sin Playground), VSR-TM11
(Hikers of MacLehose Trail Section 10), VSR-TM12
(Visitors of Sam Shing Temple in Castle Peak Road – Castle Peak Bay), VSR-PP2
(Workers at EMSD Tuen Mun Vehicle Servicing Station and DSD Pillar Point STW),
VSR-PP3 (Workers at River Trade Terminal), VSR-PP4 (Workers at Tuen Mun Area
40), VSR-PP6 (Recreational Users of Butterfly Beach Park), VSR-NL1 (Workers and
Travelers at Hong Kong International Airport), VSR-NL2 (Travelers at Hong Kong
Boundary Crossing Facilities), VSR-NL3 (Workers and Future Residents at MTR Siu
Ho Wan Depot), VSR-LT1 (Residents of Lo Fu Hang), VSR-LT2 (Vehicle Travellers
on Yuen Long Highway (Eastbound)), VSR-LT3 (Trail Walkers on Fu Tei Country
Trail and Lam Tei Irrigation Reservoir), VSR-LT4 (Visitor of Nam On Fat Tong in
Fu Fuk Road), VSR-LT5 (Recreational users of Fuk Hang Tsuen Basketball Court),
and VSR-LT6 (Travelers of Fuk Hang Tsuen Road).
15.10.1.8 In accordance with the criteria
and guidelines for evaluating and assessing impacts as state in Annex 10,
Clause 1.1(c) of the EIAO-TM, overall, it is considered that the residual
landscape and visual impacts of the proposed development are acceptable with mitigation during the construction and
operational phases.
15.11
Cultural Heritage
15.11.1.1
The three Sites of Archaeological Interest, namely Shek Kok Tsui, Fu Tei
Ha and So Kwu Wat are avoided and will not be impacted and the works area of the Project is considered to have no archaeological
potential. Therefore no adverse archaeological impact due to the
proposed works is anticipated. No mitigation measures is required. As a precautionary measure, the project
proponent and his/her contractor are required to inform Antiquities and
Monuments Office (AMO) immediately when any antiquities or supposed antiquities
under the Antiquities and Monuments Ordinance (Cap. 53) are discovered during the course of works.
15.11.1.2
Desktop review identified no declared or proposed monuments, sites/
buildings/ structures in the new list of proposed grading items, and Government
historic sites identified by AMO in the cultural
heritage assessment area.
15.11.1.3
A grade 2 building (GB-02) is
located about 49m from the nearby works area for re-provisioning of facilities.
Built heritage items BH-02 and BH-03 are located next to works area. Potential
vibration impact may be a concern due to vibration generation activities in the
works area. Special attention should be
paid to design proposal, method of works and choice of machinery should be
targeted to minimize adverse impacts to the GB-02, BH-02 and BH-03. Any vibration and building movement induced
from the proposed works should be strictly monitored to ensure no physical
damages made to the heritage sites during the course of
works. Monitoring proposal for the GB-02, including checkpoint locations,
installation details, response actions for each of the Alert/ Alarm/ Action
(3As) levels and frequency of monitoring should be submitted for AMO's
consideration.
15.11.1.4 For operation phase, no adverse
impact was identified, and no mitigation measure is required. And no adverse
residual cultural heritage impact is anticipated.