CBL Alignment Options
17.1.1 The routing of the CBL is proposed as an east-west connection between Wan Po Road and TKO-LT Tunnel across the south of the TKO Town Centre. Four route alignments for the CBL have been identified.
17.1.2 According to “Further Development of Tseung Kwan O Feasibility Study – Final Topical Study Report: Cross Bay Link” (2005), the four route alignment options are appraised broadly in terms of traffic performance, compatibility with land use planning intentions, and potential environmental impacts. Based on the outcome of the assessment, Route Alignment Option 2 is considered suitable. Consequently, the two structural forms of the option – Scheme A (Bridge Arrangement) and Scheme B (Tunnel Arrangement) is further assessed in terms of four aspects including engineering, highway traffic, environmental and cost. In overall terms, Scheme A (Bridge Arrangement) of Route Alignment Option 2 is selected as the preferred CBL scheme.
17.1.3 Following a preliminary evaluation of the long list of bridge options, six design options were identified as technically feasible for the project and were shortlisted in the Final Design Options Review Report (2010). According to the public consultation, Design Option 5, the Eternity Arch, is carried forward as the preferred option for CBL.
Preferred Construction Method
17.1.4 Off-site precast segmental construction and off-site erection will be adopted for the construction of the CBL. The environmental impact was one of the key reasons for adopting these construction methods since moving construction away from the site reduces the nuisance to local residents and the impact on the local environment. However, the purpose of the off-site fabrication is not to transfer the problems elsewhere. The concrete pre-casting and steel fabrication yards in China are purpose-built facilities, with production line practices implemented. Hence, the impacts would be better managed and controlled.
17.2
Construction
Descriptions
17.2.1 The CBL is targeted to be commissioned by 2020. Hence, the construction of the CBL will start in late 2016, for completion in 2020, with a construction period of 4 years.
17.2.2 The major construction works would include the following activities:
CBL
·
Foundations – Installation of
piles by marine piling rigs, erection of cofferdam, building of pile caps, and
building of piers;
·
Substructure and superstructure
– erection of concrete deck segments of the approach, and installation of main
bridge and side spans; and
·
Construction of the cycle track
ramp.
Road D9
·
Sea wall modification and
strengthening;
·
Ground improvement works;
·
Piling and erection of noise
barrier.
17.3.1
During construction phase,
potential dust impact would be generated from the soil excavation activities,
backfilling, site erosion, storage of spoil on site, and transportation of soil
during the construction phase. Quantitative fugitive dust assessments have
therefore been conducted for the construction of CBL. The assessment result has
concluded that watering once per hour on exposed worksites and haul road is
recommended to achieve dust removal efficiency of 91.7%. In addition to the watering and required
intensity, the Contractor will also be obliged to follow the procedures and
requirements given in the Air Pollution Control (Construction Dust)
Regulation. With the implementation of
recommended mitigation measures, no adverse air quality impact is anticipated during
the construction phase.
17.3.2 Cumulative air quality impact arising from the vehicular emissions from the open roads, tunnel portals and the chimney emissions from various industries in the TKOIE during the operational phase has been assessed. The assessment results have concluded that all the 1-hour, 24-hour and annual NO2 and RSP concentrations would comply with the relevant AQOs. Hence, no adverse cumulative air quality is therefore anticipated during the operational phase.
17.3.2.1
Overall, it was
concluded that during the both the construction and operational phases of CBL,
Annex 12 of the TM-EIAO would be fully complied with.
17.4.1
During construction phase,
construction noise impacts would arise from major construction works for CBL
(i.e. installation of piles by marine piling rigs, erection of cofferdam,
building pile caps, erection of noise barrier, etc. Unmitigated
construction noise assessment results indicate exceedance of the daytime noise
criteria, and therefore, mitigation measures are required. However, with the implementation of proposed
mitigation measures (i.e. good site practice, use of quite plant and working
methods, use of site hoarding/shrouds/temporary noise barriers, etc.),
predicted mitigated noise levels at all Noise Sensitive Receivers will be
within the respective noise criteria due to the construction of CBL. The
predicted cumulative noise impacts exceed the noise criterion for Planned Primary School & Secondary School near Wan Po Road (R33 &
R34) during examination period. The contractor should therefore
further confirm the construction program of this NSR at the commencement of the
CBL construction work. The CBL
construction work at Road D9 will be scheduled to avoid the examination period
at the Planned Primary and Secondary School (R33 & R34) if the educational
institution at R33 and R34 are constructed before the commencement of CBL
construction work.
17.4.2
For operational phase,
noise impacts are contributed by traffic at Road D9 and CBL and therefore a 6m
height partial enclosure along road D9 and low noise surfacing on CBL and Road
D9 have been proposed to mitigate impacts.
However, exceedance of the noise criterion is still predicted at planned
development residential block R22 of Lohas Park Stage 3. As R22 was previously assessed, mitigation
measures have been proposed by the Area 86 development proponent.
Further analysis revealed that the noise
exceedance is predominantly due to the Road R5 and model
predictions indicate that the new roads contribute less than 1dB(A) to the
overall noise level and the predicted noise level arising from new roads is
less than 70dB(A). No further actions are therefore required by the CBL Project
proponent.
17.4.2.1 Overall, in respect of both the construction and operational phases of CBL, Annex 5 of the TM-EIAO would be complied with.
17.5.1 A marine GI with sediment sampling and laboratory testing has been undertaken and analysed in accordance with the requirements in ETWB 34/2002. It is estimated that a total of approximately 4,300m3 marine deposit is required to be dredged. Amongst the dredged volume, approximately 97% is Category L sediment. Category Mp, Mf, and H sediments contribute approximately 3% of the total volume.
17.5.2
Overall, it was concluded that in respect of the marine sediment
to be excavated and disposed at sea during the construction of the CBL, Annex
7 of the TM-EIAO would be complied with.
17.6.1 Potential waste management implications from the generation of waste during the construction and operational phase of the Project have been evaluated. A range of best practice mitigation measures have been proposed for implementation by the Contractor during the construction period to minimise waste generation and off-site disposal. In addition, monitoring and audit measures are proposed to ensure that robust measures are promoted to minimise impacts and that waste is controlled effectively.
17.6.2
With the implementation of all the proposed mitigation measures, no
adverse residual waste management implications were anticipated during both the
construction and operational phases.
Overall, it was concluded that the waste management implications of CBL
would comply with Annex 7 of the TM-EIAO.
17.7.1
During construction phase,
water quality impacts may arise from pile excavation works, construction site
runoff and sewage from workforce. For
pile excavation works, assessment results indicate that non-compliance with the assessment
criteria for WSD’s salt water intakes for flushing water (10mg/L), or any Fish
Culture Zone in the vicinity, is not anticipated. Although the interface of the marine works
for CBL project with T2 is anticipated, the plume from CBL was well confined in
Junk Bay area and superpositions of plume with T2 is not anticipated. With the implementation of proposed
mitigation measures, adverse water quality impacts during construction phase
are not anticipated.
17.7.2
During operational phase,
no significant change in the hydrodynamic and water quality regime is
anticipated. No mitigation measures such
as maintenance dredging are therefore required.
Due to potential runoff from road surfaces, proper drainage systems with
silt traps and oil interceptors should be installed, maintained and cleaned at
regular intervals as a precautionary measure.
17.7.2.1
Overall, it was concluded that water quality
impacts would comply with Annex 6 of the TM-EIAO during both the construction
and operational phases of CBL.
17.8.2 The CBL would cause only limited (< 0.3ha) soft substrate seabed and marine waters loss and potentially affect a section of 450m vertical seawall with low coverage of common soft and hard corals. These habitat loss impacts ranked as insignificant to minor due to the small size and low ecological value of the habitats. And it is anticipated that there will be new seawalls along the waterfront of the future landing point/reclamation, and artificial intertidal and subtidal hard substrate habitat is available for intertidal fauna and coral colonisation after construction.
17.8.3 Only limited marine water quality impacts are anticipated as only 12 pier sites are needed for the project and no reclamation will be performed. Other impacts are also minor or insignificant. The residual impacts, mainly habitat loss, are considered acceptable. No species ecological monitoring programme is needed. Overall, it was concluded that ecological impact due to CBL would comply with Annex 8 of the TM-EIAO.
17.9.2 The CBL would cause only limited (< 1ha) loss of fishing ground of low to moderate production. These habitat loss impacts ranked as insignificant to minor due to the small size and low ecological value of the habitats.
17.9.3 Only limited marine water quality impacts are anticipated as only 12 pier sites are needed for the project and no reclamation will be performed. Other impacts are also minor or insignificant.
17.9.4 The residual impacts, fishing ground loss, are considered acceptable. No specific fisheries monitoring programme is needed. Overall, it was concluded that CBL would comply fully with Annex 9 of the TM-EIAO.
17.10 Cultural Heritage Impact
17.10.1
A comprehensive Marine Archaeological
Investigation was completed which followed exactly the methodology set out by
the HKSAR Antiquities and Monuments Office.
The study did not locate any cultural heritage resources. The diver
survey indicated that in many areas the seabed had been disturbed by previous
construction work. Consequently, no
further action or mitigation is therefore required. Overall, the CBL
would comply fully with Annex 10 of the TM-EIAO.
17.11.1 A preliminary qualitative risk assessment for LFG hazards associated with the proposed CBL development has been conducted. The TKOL-II/III is considered as a “Medium” source of gas migration due to occasional high carbon dioxide levels of more than 5% v/v above natural background level detected in the gas monitoring wells though LFG control measures such as in the active gas extraction system installed. The source-pathway-target analysis indicates that the overall risks to the receivers within the 250m Consultation Zone during both construction and operational phases would be categorised as “Low to Medium”. Appropriate precautionary measures and monitoring were reccomended to minimise the potential risk of LFG migration to the respective targets and requirements of Annex 7 of the TM-EIAO.
17.12
Landscape and Visual Impact
17.12.1.1
The proposed development and associated works follow in principle the
planning intentions from the draft Tseung Kwan O – Outline Zoning Plan
(S/TKO/20). However, the scale of CBL
together with concurrent projects, namely, TKO-LTT will inevitably result in
some landscape and visual impacts.
17.12.1.2
Based on the tree survey report on CBL, approximately 308 no. of trees
will be affected (LR3), of which approximately 58 no. are proposed to be
transplanted, and approximately 250 no.
trees are proposed to be felled (including 190 no. Leucaena leucocephala and 60
no. common trees). Due to construction of the CBL, it is unavoidably considered
to remove the affected trees. Affected trees with high to medium amenity value
and medium survival rate are proposed to be transplanted. Trees surveyed within
the proposed works boundary are primarily common species. There are no LCSD
Champion Trees, Registered Old and Valuable Trees and Protected Species under
Cap 586 Protection of Endangered Species of Animals and Plants Ordinance. It is
expected approx. 67 heavy standard sized trees shall be planted as compensatory
tree planting. The overall residual impact on vegetation along Wan O Road (LR3) is considered as acceptable with mitigation measures.
17.12.1.3
With the proposed mitigation measures including the compensatory planting
and aesthetic treatments, the Junk Bay Coastal Landscape (LCA 1) will still
suffer from slight landscape impact during construction and operation due to
the artificial engineering structure which is incompatible with the natural
Junk Bay character.
17.12.1.4
LCA2 - There will be slight impact on Reclamation / ongoing major
development landscape due to the operation of CBL. However, with the proposed
mitigation measures including the aesthetic design of the built structures and
soft landscape treatment works, it is considered that the residual impact on
this LCA is insubstantial.
17.12.1.5
LCA3 – Tseung Kwan O Industrial Urban Landscape will be subject to
insubstantial impact as this LCA is relatively far away from the CBL.
17.12.1.6
LCA4 – Chiu Keng Wan Coastal Upland and Hillside Landscape will be
subject to insubstantial impact as this LCA is relatively far away from the
CBL. However, this LCA will definitely be affected by the interface project:
TKO-LT Tunnel.
17.12.1.7
LCA5 – Tseung Kwan O Landfill Landscape (Stage II and III) will be
subject to insubstantial impact as this LCA is relatively far away from CBL and
will not be affected.
17.12.1.8
LCA6 – Tseung Kwan O Miscellaneous Urban Fringe Landscapewill be subject
to insubstantial impact as this LCA is relatively far away from CBL and will
not be affected.
17.12.1.9
LCA7 – High Junk Peak Coastal Upland and Hillside Landscape will be
subject to insubstantial impact as this LCA is relatively far away from CBL and
will not be affected.
17.12.1.10
LCA8 – Residential Urban Fringe Landscape will be subject to
insubstantial impact as this LCA is relatively far away from CBL and will not
be affected.
17.12.1.11
There is expected to be some minor impact upon the sea waterbody in Junk
Bay (LR1). The sea water body will be permanent
lost due to the construction of the piers for CBL bridge. Residual impacts
after 10 years of operation are expected to be slight.
17.12.1.12
There is expected to be negligible impact upon the Landscaped Area and
Plantation within High-rise residential development in CDA 86 (LOHAS Park)
(LR2). It is considered that the residual impact is expected to be
insubstantial.
17.12.1.13
There is expected to be negligible impact upon the Plantation within
Vacant land (LR4), It is considered that the residual impact is expected to be
insubstantial after year 10.
17.12.1.14
There is expected to be negligible impact upon Plantation within
Industrial Building (LR5). Residual
impact after Year 10 is expected to be insubstantial.
17.12.1.15
There is expected to be negligible impact upon Woodland at Foothill and
Hillside (LR6). Residual impact after Year 10 is expected to be insubstantial.
17.12.1.16
There is expected to be negligible impact upon Grassland and Scrubland at
Hillside in Chiu Keng Wan (LR7). Residual impact after Year 10 is expected to
be insubstantial.
17.12.1.17
There is expected to be negligible impact upon Vegetation of clustered
newly planted trees and shrubs scattered on Tseung Kwan O Stage II and III
Landfill Area (LR8). Residual impact after Year 10 is expected to be
insubstantial.
17.12.1.18
There is expected to be negligible impact upon Nature Rocky and Sand
Shoreline in Chiu Keng Wan (LR9) and Plantation at Wasteland / Construction
Area in Chiu Keng Wan (LR10). Residual impact after Year 10 is expected to be
insubstantial.
17.12.1.19
There is expected to be negligible impact upon Vegetation along the
Coastline Adjacent to Lohas Park Road (LR11). Residual impact after Year 10 is
expected to be insubstantial.
17.12.1.20
There is expected to be negligible impact upon Roadside Planting in Lohas
Park Road (LR12). Residual impact after Year 10 is expected to be
insubstantial.
17.12.1.21
There is expected to be negligible impact upon Seawall in Tseung Kwan O Industrial Estate (LR13).
Residual impact after Year 10 is expected to be insubstantial.
17.12.1.22
Lei Yue Mun and Tathong Channel are a unique public asset and natural
visual resources as viewed from Shau Kei Wan, providing an open seascape along
the Junk Bay. The proposed CBL, particularly the pier structure will induce
partial blockage of views and permanent loss of open seascape view. The
cumulative visual impacts can only be slightly mitigated by minimizing area,
avoidance of excessive height and bulk of buildings and structures and
construction period. Therefore, the VSRs (CDA1) located in close proximity to
CBL will still suffer from moderate residual visual impact of the CBL
17.12.1.23
While for the proposed Open Space in Area 74 (O3), and Planned
recreational users in TKO Stage I Landfill (REC1), the residual impact would be
slight due to screening/amenity planting along the waterfront promenade will be
fully established and can soften engineering structure built in Junk Bay.
17.12.1.24
The Planned proposed “Central Avenue” user in Town Centre South near the
promenade in open space of TKO Area 68 and the promenade user in the former TKO
Stage I Landfill site (O1), the Planned waterfront near the Eastern Channel in
open space of TKO Area 68 (O2), and Planned Residential area of TKO
Area 65, 66 and 68 (R7) will have direct and close range views to the CBL and TKO-LTT. The cumulative visual impacts can only be
mitigated by using visually unobtrusive building material and refinement of
engineering design. Screening
planting/amenity planting in the open space itself is expected to have minor
screening effect to these views because CBL are elevated. Therefore, the VSRs (O1, O2 and R7) will
still suffer from moderate residual visual impact of CBL and TKO-LT Tunnel.
17.12.1.25
The proposed Open Space in Area 74 (O3), and Planned recreational users
in TKO Stage I Landfill (REC1), the residual impact would be slight due to
screening/amenity planting along the waterfront promenade will be fully
established and is expected to have screening effect on CBL and TKO-LT Tunnel. Residents of Ocean Shores (R2) will have
direct, close views to the new CBL and TKO-LT Tunnel which is immediately
adjacent or very close to the VSRs.
Mitigation in the form of screening planting, refinement of structure
and architectural design of road structures will help in reducing these visual
impacts. However, the VSRs will still be
subject to the partial blockage of views and permanent loss of open
seaview. Therefore, the VSRs (R2) will
still suffer from moderate residual visual impact of CBL and TKO-LT Tunnel.
17.12.1.26
The landscape and visual impact assessment has been conducted according
to the criteria and guidelines for evaluating and assessing impacts as stated
in Annex 10 and 18 of the TM-EIAO, it is considered that the identified
residual impacts, taking account of both importance and degree of compliance,
will be acceptable with mitigation measures.
17.13 Environmental Monitoring and Audit Requirement
17.13.1
It is recommended to
implement an Environmental Monitoring and Audit (EM&A) programme throughout
the entire construction period to monitor the environmental impacts on the
neighbouring sensitive receivers regularly.
17.13.2
An EM&A Manual has been
prepared as a standalone document to specify the monitoring requirements,
timeframe and responsibilities for the implementation of the environmental
mitigation measures identified in the EIA process.
17.13.3
An Environmental Mitigation
Implementation Schedule is included in the EM&A Manual to summarises all
the measures, the implementation location, timeframe, agency etc.