CONTENTS
2.1 General Description of the
Project
2.3 Consideration of
Alternatives
3 Key Findings of the Environmental Impact Assessment
3.4 Waste Management
Implications
3.7 Landscape and Visual
Impact
TABLES
Table 2‑1 Considerations
for Proposed Cavern Options
Table 2‑2 Considerations
for Proposed Tunnel Options
Table 2‑3 Considerations
of Construction Methods for Tunnel and Cavern
Table 2‑4 Potential
Concurrent Projects
Table 3‑1 Summary
of Predicted Cumulative Construction Dust Impact (Mitigated Scenario)
Table 4‑1 Summary
of EM&A Requirements
FIGURE
General
Layout Plan |
a)
Construction of the relocated DHSRs and
associated pumping stations and water main laying works;
b)
Construction of tunnels, adits, ventilation
system and caverns for accommodating the relocated DHSRs and the associated
facilities;
c)
Terminating the operation of the existing
DHSRs and the associated facilities; and
d)
All other associated works that are incidental to and necessary for the completion of the
Project.
Table 2‑1 Considerations
for Proposed Cavern Options
Land Matter |
Environmental Considerations |
Other Considerations |
Preferable Option |
|
Cavern Option 1 - hillsides north of Chuk Yuen North
Estate |
In government land (“Green Belt” zone) |
· Noise and dust
impacts during open excavation but controllable when inside cavern · Relatively further
away from the Lion Rock Country Park (LRCP) compared to Options 2 and 3 |
· In close proximity
to the existing DHSRs allowing the relocated DHSRs to be housed and
positioned at similar level as the invert levels of the existing DHFWSR and
DHSWSR · The geology of the
proposed relocation site, belonging to hard granite with no obvious weak
zones and faults, is most suitable for construction of large caverns · Great public
concern on the blasting impact on their private slopes due to its close
proximity from the proposed caverns |
No |
Cavern Option 2 - hillside north of Ma Chai Hang FWSR |
In government land (“Green Belt” zone) |
· Noise and dust
impacts during open excavation but controllable when inside cavern · Closer to LRCP than
Option 1 |
· Relevant Wong Tai
Sin District Council members and local public requested to further revise the
cavern location in order to maximise the distance between the proposed
caverns and nearby housing estates |
No |
Cavern Option 3 - hillside northwest of Ma Chai Hang FWSR |
In government land (“Green Belt” zone) |
· Noise and dust
impacts during open excavation but controllable when inside cavern, and less
impact to nearby residents is anticipated compared with Option 2 · Closer to LRCP than
Option 2 but no encroachment |
· Watermains laying
works at Chui Chuk Street will no longer be required |
Yes |
Cavern Option 4 – hillside north of Lion Rock Park |
In government land (“Green Belt” zone) |
· Greatest distance
from nearby residential areas amongst all the four options · Closer to LRCP than
Option 2 but no encroachment |
· Potential impact to
the structural integrity of MTRC Shatin-Central Link (SCL) Tunnel due to
proximity · Poor ground
condition |
No |
Table 2‑2 Considerations for Proposed Tunnel Options
Tunnel
Options |
Emergency
Vehicular Access (EVA) |
Land
Matters |
Environmental
Considerations |
Other
Considerations |
Preferable Option |
Tunnel
Option 1 – Shatin Pass Road near Fat Jong Temple |
Not recommended due
to constraint in Shatin Pass Road (i.e. gradient 1:5,
greater than 1:10) |
Inside Government
land |
· Comparatively
lesser air / noise sensitive receivers surrounding the proposed tunnel
portal, but will affect woodland and stream habitat · Relatively
short tunnel length among other options which will produce lesser excavated
material, dust and noise impact. · Low
visual and landscape impact generated from construction of tunnel portal |
· Close
to existing water main network to Fung Wong Fresh and Salt Water Service
Reservoir · Could
be used as utility gallery for water mains to Fung Wong Fresh and Salt Water
Service Reservoir, also serve as emergency exit |
No |
Tunnel
Option 2 – Shatin Pass Road near Ying Fuk Court |
Not recommended due
to inside private slope |
Inside private
slope |
· Locating
on existing slope and opposite to Wong Tai Sin Hospital mainly which is
locating away from residential areas · Potential
noise and dust impact, longer tunnel length among Options 1-5, 6a & 6b
leading to more excavated materials · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· Close
to Chuk Yuen North Estate, CLP’s pylons |
No |
Tunnel
Option 3 – Wing Chuk Street |
Not recommended due
to inside private slope |
Inside private
slope |
· Locating
on existing slope and opposite to Chuk Yuen North Estate · Potential
noise and dust impacts, generated excavated materials will be similar for
Options 3-5, 6a & 6b · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· Close
to Chuk Yuen North Estate |
No |
Tunnel
Option 4 – Junction between Wing Chuk Street & Chui Chuk Street |
Not recommended due
to inside private slope |
Inside private
slope |
· Locating
on existing slope and opposite to Pang Ching Court · Potential
noise and dust impacts, generated excavated materials will be similar for
Options 3-5, 6a & 6b · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· Close
to Chuk Yuen North Estate and Pang Ching Court |
No |
Tunnel
Option 5 – Chui Chuk Street |
Feasible,
significant traffic impact anticipated during construction stage |
Inside Government
land |
· Locating
on existing slope and opposite to Pang Ching Court · Potential
noise and dust impact, generated excavated materials will be similar for
Options 3-5, 6a & 6b · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· Close
to Chuk Yuen North Estate and Pang Ching Court · Impact
on Chui Chuk Street which is the sole access road for Tsui Chuk Garden · There
is constraint on laying water mains in Chui Chuk Street due to existing UUs · Could be considered as EVA /
watermains laying to existing network |
No |
Tunnel
Option 6a & 6b – Ma Chai Hang Fresh Water Service Reservoir |
Feasible, further
liaison with FSD is required to upgrade the existing access road |
Inside Government
land |
· Potential
generate larger noise and dust impacts to Tsui Chuk Garden due to close
proximity of the work site, direct loss of woodland habitat (Option 6a) for
construction of booster pumping station and widening of the existing access
road · Relatively
short tunnel length which produce lesser excavated material · Visual
and landscape impact generated from construction of tunnel portal owing to
the close proximity to nearby housing estates |
· Far
away from existing water main network, not suitable for laying water mains
· The
existing substandard access road will need to be widened for use by emergency
vehicles, and the slopes along the access road need to be upgraded. · Larger
blasting impact to adjacent areas · WTSDC
member and the residents of Tsui Chuk Garden raised their great concern on
the tunnel portal location · Local
public had great concern about temporarily closure of the access road to Ma
Chai Hang FWSR during the construction |
No |
Tunnel
Option 7 – Near the entrance of Lion Rock Park |
Separate EVA not
required as passage length not exceeding 750m |
Inside Government
land |
· Relatively
longer tunnel length which produce larger quantity of excavated material · Potential
dust and noise impacts to the nearby sensitive receivers are expected to be
longer due to longer construction programme when compare to Tunnel Options 6a
& 6b · Direct
loss of woodland habitats due to construction · Potential
impact on existing flora species of conservation importance · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· No
additional pumping station and widening of existing access road to Ma Chai
Hang FWSR would be required · Relatively
low blasting impact to adjacent areas · Relatively
less public concern |
No |
Tunnel
Option 8 - Adjacent to the Lion Rock Park Transit Nursery Landscape Section |
Separate EVA not
required as passage length not exceeding 750m |
Inside Government
land |
· Direct
loss of existing plantation habitats on slope
· Relatively
longer tunnel length which produce larger quantity of excavated material for
disposal · Potential
dust and noise impacts to the nearby sensitive receivers are expected longer
due to longer construction programme when compare to Tunnel Options 6a &
6b · Relatively
low visual and landscape impact generated from construction of tunnel
portal |
· No
additional pumping station and widening of existing access road to Ma Chai
Hang FWSR would be required · Relatively
low blasting impact to adjacent areas · Potential
effect to the hikers to the LRCP |
Yes |
Table 2‑3 Considerations
of Construction Methods for Tunnel and Cavern
Construction Methods Options for
Tunnel and Cavern |
Engineering Consideration |
Environmental Consideration |
Construction Duration |
Other Considerations |
Recommendation |
Drill
and break (for
tunnel) |
· Commonly
adopted in tunneling project |
· Noise
and dust impacts during open excavation but controllable when inside cavern |
Slower production and longer
construction duration |
- |
Recommended |
Drill
and blast (for
tunnel and cavern construction) |
· Commonly
adopted in tunneling project |
· Noise
and dust impacts during open excavation but controllable when inside cavern |
Moderate production and construction
duration |
· Potential
hazard from the delivery, storage and handling of explosives · Requires
permit for use of explosives |
Recommended |
Cut
and Cover (initial
short section connecting to the portal) |
· Suitable
for the tunnel section where the rock cover is less than half of tunnel span |
· Noise
and dust impacts but controllable when noise barrier, dust screen and water
spraying are implemented |
Shorter construction duration |
· Temporary
traffic arrangement and excavation and lateral support is required |
Recommended |
Tunnel
Boring Machine (TBM) |
· Suitable
for small to medium size tunnel · Requires
larger launching area · Not
suitable for abrupt bend |
· Less
noise and dust impact |
Shorter construction duration |
· Limited
works space in tunnel portal · High
capital cost |
Not
recommended |
Use
of chemical expansion agent |
· Quiet |
· No
noise and dust impact |
Very slow production and very long
construction duration |
· Drilling
is still required · Not
suitable for fractured and weak rock mass |
Not
recommended |
Table 2‑4 Potential Concurrent Projects
Project
Name |
Target Work Commencement Date |
Target Work Completion Date |
CE 28/2017 (HY) - Pedestrian Link near Chuk Yuen
North Estate – Design and Construction |
Mid 2023 |
Mid 2029 |
CE 48/2018 (HY) - Improvement of Lion Rock Tunnel |
Mid 2024 |
[1] |
[1] Project
details is not available for consideration at time of reporting. |
·
Air quality impact
·
Noise impact
·
Water quality impact
·
Waste management implications
·
Land contamination
·
Ecological impact
·
Landscape and visual impact
·
Hazard to life
Table
3‑1 Summary of Predicted Cumulative Construction
Dust Impact (Mitigated Scenario)
|
Pollutant Concentration (μg/m3) |
Compliance |
||||
TSP |
RSP |
FSP |
||||
1-hr |
24-hr (10th Highest) |
Annual |
24-hr |
Annual |
||
ASRs |
197 -361 |
71 – 77 |
31 – 36 |
53 – 55 |
22 - 24 |
Yes |
AQOs/ EIAO-TM
Criteria |
500 |
100 |
50 |
75 |
35 |
-- |
Note: Value in blanket () is no. of daily exceedance.
Table 4‑1 Summary of EM&A Requirements
Environmental Aspect |
Construction Phase |
Operation Phase |
Air quality impact |
√ |
× |
Noise impact |
√ |
√ (commissioning test
prior to operation ) |
Water quality impact |
√* |
× |
Waste management implications |
√* |
× |
Land contamination |
× |
× |
Ecological impact |
√* |
× |
Landscape and visual impact |
√* |
√* |
Hazard to life |
× |
× |
Remarks: √ - Required (monitoring & site
audit); √*- (site audit only); × - Not Required |
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