3 Project Description and Construction
Methodologies
3.2 Tentative
Implementation Programme
3.3 Consideration
of Alternative Construction Methodologies
3.4 Preferred
Construction Methodology – Works Within Study Area
3.5 Preferred
Construction Methodology – Works Outside Columbarium / Crematorium Site
3.1.1.1
Section 2 has described the approaches
adopted to avoid and minimise various environmental impacts throughout the
design process. As mentioned in Section
2.1, the site formation of the original design is about 10ha as stated in EIA
Study Brief (ESB-271/2014), however, during the design process, environmental
impacts are considered, and the site formation of the final design has reduced
to about 8ha. The final design has therefore been taken forward
as the basis for this EIA to demonstrate that all statutory requirements under EIA
Study Brief (ESB-271/2014) and the Environmental Impact Assessment Ordinance
(EIAO) are complied with. A brief summary
of key elements of the project is given below:
Area |
Proposed
Works |
Works Within Study Area |
·
Site formation of about 8ha of land for
proposed C&C Facilities (including the proposed pick-up and drop-off area
for shuttle buses). |
|
·
Widening of the existing Sha Ling Road
(about 900m) - from existing 3m wide to a 7.3m wide single two-lane
carriageway, including its associated noise barriers. |
|
·
Construction of internal roads for
C&C Facilities. |
|
·
Widening of the existing Lin Ma Hang
Road (about 1.4km long) – from existing 6m wide to a 7.3m wide single two-lane
carriageway, including its associated noise barriers. |
|
·
Construction of a new road (about 600m)
including a section of viaduct connecting platform for Crematorium and Man
Kam To Road. |
|
·
Construction of the pick-up and drop-off
point at Man Kam To Road. |
Outside the Columbarium / Crematorium Site |
·
Temporary pick-up
and drop-off points of shuttle buses for grave-sweepers
during festive periods at MTR Kwu Tung Station,
Sheung Shui Landmark North Public Transport Interchange, MTR Fanling Station,
and layby at Pak Wo Road near Flora Plaza. ·
Necessary landscaping, sewerage,
waterworks and utility works for the proposed development along Man Kam To
Road. ·
Barging point in Siu Lam. |
3.1.1.2 The construction of the proposed works elements within the Study Area would involve relatively more construction activities, especially those for the site formation work and associated infrastructure. In comparison, the works for the temporary pick-up and drop-off points of shuttle buses for the MTR stations would be very minor and only involve some retrofitting of existing facilities such as rearrangement of planter and street furniture (i.e. street lighting and railing) and bus routes. Major excavation works etc. would not be required. For MTR Kwu Tung Station (including the PTI and shuttle bus services area), it will be constructed under the Planning and Development Study on North East New Territories (NENT) Contract and will be available by 2026. In addition, a barging point currently used by the Express Rail Link project at Siu Lam is added.
3.1.1.3 The barging point is located off-site along Tsing Fat Street, Tuen Mun. In order to reduce the impact on road traffic, surplus inert construction and demolition (C&D) materials from the construction of the C&C facilities at Sandy Ridge Cemetery and Lin Ma Hang Road will be stored at a temporary stockpile area on-site. The surplus inert C&D materials will be transported to designated barging point facility by lorries, and then transported by barges for the reuse of other concurrent projects. The maximum number of barge movement is 2 round trips per day. The current location is an existing barging point used by the Express Rail Link project. Minor construction works for the tipping halls and new ramps are required. No maintenance dredging is required and no night-time operation is anticipated.
3.1.1.4 As improvement works at the barging point will be land-based on existing hard standing / developed area and levels of marine traffic will be very low and following route to avoid areas of high dolphin density (Section 9 for details), it is considered that the use of this site is unlikely to change, the evaluation of habitat quality and potential impacts on the coastal environment is considered not necessary.
3.1.1.5 The comparison of the scope of works and designated projects of the original design and the current design is given in Table 2.1 below:
Table 3.1 The comparison of
the scope of works and designated projects of the original design and the
current design
|
Description (Study Brief ESB 271/2014) |
Original Design |
Current Design |
Scope of works |
Site formation and associated works of about 10
hectares of land including landscaping, geotechnical, drainage and sewerage
works, waterworks, and other utilities services for development of C&C
faculties at Sandy Ridge Cemetery; |
P (10 ha) |
P (8 ha) |
Road works including access road, tunnel and
viaducts within Sandy Ridge Cemetery; |
P (1 tunnel and
6 viaducts) |
P (Tunnel
removed and only 1 viaduct required) |
|
Pedestrian walkway between MTR Lo Wu Station and
proposed columbarium; |
P |
O |
|
Widening the eastbound of Choi Yuen Road near MTR
Sheung Shui Station from 1-lane to 2-lane carriageway (widening by about 3m)
for about 400 length |
P |
O |
|
Widening a section of Lin Ma Hang Road (about 1km
in length) from 6.5 to 7.3m |
P |
P |
|
Designated projects |
Item A.1 – A road which is an expressway, trunk
roads, primary distributor road or district distributor road including new
roads, and major extension or improvement to existing roads; |
P |
O |
Item A.8 – A road or railway bridge more than 100
m in length between abutments; |
P |
P |
|
Item I.1
(b)(vii) – A drainage channel or
river training and diversion works which discharges or discharge into an area
which is less than 300 m from the nearest boundary of an existing or planned
conservation area. |
P |
P |
3.2
Tentative Implementation Programme
3.2.1.1
It is anticipated that the site formation and associated
infrastructural works for the development of columbarium, crematorium and
related facilities will be commenced in the 3rd quarter of 2017 and
is targeted for completion by 2022. The tentative construction programme is
given in Appendix
3.1.
3.2.1.2
A summary of the key dates for construction phase is given below. All
these key dates are tentative and would be subject to amendment as the design
evolves.
Table 3.2 Summary of key construction dates
Key
Construction Elements |
Tentative Dates |
|
Commencement |
Completion |
|
Columbarium (site formation, retaining
walls, slopes, internal roads, etc.) |
Q3 2017 |
Q4 2020 |
Crematorium (site formation, retaining
walls, slopes, internal roads, etc.) |
Q3 2018 |
Q4 2021 |
New road with viaduct |
Q3 2019 |
Q4 2022 |
Widening of Sha Ling access road |
Q3 2017 |
Q4 2020 |
Utilities laying |
Q1 2020 |
Q2 2022 |
Lin Ma Hang Road Widening and associated
slopes, etc. |
Q2 2019 |
Q2 2022 |
3.3
Consideration of Alternative Construction
Methodologies
3.3.1.1
Section
3.1 has
described the keys elements of works required from the proposed development at
Sandy Ridge. In order to develop these elements in an environmentally friendly
manner, a number of alternative construction methods and sequences including
the following have been considered:
·
Avoid using blasting for site formation to
reduce impulsive noise;
·
Avoid using percussive piling for site
formation to reduce impulsive noise;
·
Use of temporary stockpile area to maximise
on-site reuse of C&D materials and reduce number of trucks to barging point;
·
Use of bored pile foundation for retaining
walls to minimise impacts on underground water flow;
·
Avoid disposal by barges at Shenzhen River
or Deep Bay to minimise impacts on Shenzhen River and Deep Bay; and
·
Avoid disposal to landfill.
3.3.2
Avoid Using Blasting for Site Formation
3.3.2.1
Given the extent of site formation and the local geological
conditions, there are two possible ways for the excavation for the main
platforms for both the columbarium and crematorium, including using blasting or
mechanical excavation.
3.3.2.2
The benefit of using blasting for the site formation is that the site
formation work could be completed within a shorter period of time. Although the impulsive noise and the dust
generated by the blasting process could be readily mitigated by good site
practices, the transportation and use of explosives may cause concern for some
of the residents in the vicinity, especially the explosives would need to be
transported to the site via a number of heavily trafficked roads including Man
Kam To Road, and other roads along which residential premises are located in
close proximity (e.g. Sha Ling Road). In
fact, using blasting would still inevitably require mechanical equipment to
break up the boulders into manageable sizes.
3.3.2.3
In comparison, the use of mechanical excavation for the site
formation would generally require more equipment such as excavator, piling rig
and drilling rig, dump truck, etc. to be operating on site. However, it could
be seen that the site formation work for the main platforms for both the
columbarium and crematorium are located at a distance from the nearest Noise
and Air Sensitive Receivers, in the range of 250m. Quantitative analysis in Sections 4 and 5 have illustrated that, with the use
of good site practices, the construction noise caused by the site formation
work would not be the dominate noise sources, and the cumulative dust impacts would comply with the
statutory requirements.
3.3.2.4
Hence, on the basis of the above discussion, the use of mechanical
excavation for the site formation has been selected as the preferred construction
methodology.
3.3.3 Avoid Using Percussive Piling for Site Formation
3.3.3.1
As far as the foundation of retaining walls and bridge sections are concerned,
the use of percussive piling against bored pile has been considered. The
benefit of using percussive piling is to achieve a shorter construction
programme and hence a lower construction cost. However, the use of percussive
piling would inevitably generate a much higher impulsive noise.
3.3.3.2
For example, using one pneumatic driving steel pile at a distance of 250m
from the Noise Sensitive Receiver would generate a maximum noise level as high
as 77dB(A). In comparison, using a vibratory piling rig will cause a sound
pressure level of 62dB(A) at the same distance. Hence, the use of percussive
piling would cause more nuisances to the sensitive receivers.
3.3.3.3
Given the environmental setting of the Noise Sensitive Receivers in
the vicinity, such high and impulsive noise lasting for months would cause significant
nuisance on the neighbouring community.
3.3.3.4
Hence, on the basis of the above discussion, the use of percussive
piling for the foundation of retaining wall and the bridges has not be further
considered.
3.3.4
Use of Temporary Stockpile Area
3.3.4.1
Given the extent of site formation, a stockpile area will be located at the proposed columbarium site during construction phase for
temporary storage of inert soft construction and demolition (C&D)
materials. The temporary stockpile area will be located
with an approximate capacity of 9,000m3. The benefit of using stockpile area is
to provide backfill material within the site formation and thus will reduce
noise and dust generation from transportation of inert soft C&D materials
from external site.
3.3.4.2
Hence, on the basis of the above discussion, the use of temporary
stockpile area for the site formation has been selected as the preferred construction
methodology.
3.3.5
Use of Bored Pile Foundation for Retaining Walls
3.3.5.1 A wet woodland is located at the western side of the site formation of columbarium. In order to allow groundwater to pass through, the foundation design would compose of bore piles of about 0.6m in diameter and the spacing between each pile would be approximately 3.5 – 5m. As compared to other foundation designs such as (Diaphragm wall) D-wall or pipepiles, the proposed small diameter bored pile system would allow a notional free area of about 87– 91% for groundwater to pass through.
3.3.5.2 Hence, based on the above arguments, it is considered that the use of bored pile foundation for retaining walls facing the wet woodland would not cause a significant change in the groundwater flow to the wet woodland and it has been selected as the preferred construction methodology.
3.3.6
Avoid Disposal by Barges at
Deep Bay / Shenzhen River
3.3.6.1 Other than using lorries, the use of barges at Deep Bay / Shenzhen River to transport C&D materials away from the construction site has also been considered. However, the water level of Shenzhen River is shallow and there is not enough draft for the barges to navigate through. Hence, large amount of dredging work would be required and these dredging works would inevitably generate a large amount of sediment of uncertain quality.
3.3.6.2 Due to the nature of this project, the dredged sediment cannot be reused on–site and hence has to be disposed of at designated marine disposal sites. Since the sediment marine disposal sites have limited capacity, it is preferred to minimise their utilisation. Besides, Deep Bay and certain sections of Shenzhen River are famous in their biodiversity and extensive dredging would inevitably generate certain direct ecological impacts as well. Other than the large amount of sediment dredged and the direct ecological impacts, the large number of barges navigating through Shenzhen River and subsequently through Deep Bay would increase the possibility of indirect impacts on the sensitive ecological habitats in the vicinity.
3.3.6.3
Hence, on the basis of the above discussion,
the use of trucks for disposal of C&D materials during site formation has
been selected as the preferred construction methodology.
3.3.7 Avoid Disposal to Landfill
3.3.7.1
As discussed above, the surplus inert C&D materials from the construction of the
C&C facilities at Sandy Ridge Cemetery and Lin Ma Hang Road will be stored
at a temporary stockpile area on-site. In order to minimise the disposal to
landfill, the use of trucks for transport of inert surplus C&D materials to
designated barging point at Siu Lam for the reuse of other concurrent projects
has been selected as the preferred construction methodology.
3.4
Preferred Construction
Methodology – Works Within Study Area
3.4.1.1
The preferred construction methods are presented in the following
sections.
3.4.2
Site Formation
3.4.2.1
The total area for the site formation work is about 8ha. As shown in Figure 1.1. The
eastern portion of the development will comprise a total of 2 platforms. The two platforms with formation levels at +37mPD and +40mPD, will accommodate building blocks of Crematorium, Funeral Parlour,
Visitor Service Centre and associated facilities which are to be separately
implemented.
3.4.2.2
The western portion of the development
comprise of one platform with a formation level at +50mpD. It will serve as the pick-up / drop-off area for shuttle buses,
and accommodate the
building blocks for the Columbarium
and associated facilities such as joss paper burner and refuse collection point
respectively.
3.4.2.3
For the columbarium site, the site formation works for the platform is
mainly for the provision of pick-up / drop-off area to cater for visitors
during festive days. Meanwhile, cut/fill slopes will be more preferable than
retaining walls for the design of geotechnical engineering features, where more
landscaping works can be provided to mitigate the visual impacts. Most of the
columbaria buildings will be constructed along the slope to minimise the visual
impacts and the extent of site formation works.
3.4.2.4
In considering of the placing the pick-up / drop-off area decked or at
an open area, according to the current design, the future columbarium building
blocks are recommended to be sited separate from the pick-up/ drop-off area for
the following considerations:
·
An integrated complex housing the pick-up / drop-off area and the
columbarium buildings with 200,000 niches will inevitably become a
mega-structure towering over the +50mPD platform, which would introduce adverse
visual impacts to the surrounding due to its massive building bulk.
·
In view of its location, an open-air pick-up / drop-off area arrangement
will have no adverse environmental impact and will result in less energy
consumption in future operation than a covered pick-up / drop-off area, for
which mechanical ventilation system would be unavoidable.
·
The development of the columbarium at Sandy Ridge Cemetery is expected
to span over 10 years in different phases to meet the demands. If an integrated
design for columbarium and pick-up / drop-off area is used, when Phase 1 (i.e.
the completion of pick-up/ drop-off area and one of the columbarium buildings)
is completed and in operation, construction works for the following phases will
inevitably cause safety risks and nuisances to the users / visitors especially
during the festive days, which would be undesirable.
3.4.2.5
Given the size of the site formation work, the construction
methodologies have been duly reviewed to ensure that the associated
environmental impacts are optimised during this design stage. A description of the key construction stages
is given below:
Key
Stages |
Construction
Methodology |
Site Clearance |
Firstly,
trees will be cleared by backhoes and transported out of the site by crane
lorries. After that, the top soil, rock and inert debris will be cleared by
backhoes and transported to the stockpiling area for
temporary storage. The top soil will be considered to be
used for grassland reinstatement. The remaining top soil, rock and inert
debris will be transferred to or public filling area by trucks. |
|
The
surplus inert C&D materials will be transferred to the barging point at
Siu Lam for the reuse of other concurrent projects. |
Construction of haul road |
Construction
of access route mainly involves temporary
cut and fill works. Therefore, excavators and bulldozers
will be deployed to excavate and place the fill material to the desired slope
angle of the proposed access road. After placing the fill material on the
haul road, vibratory rollers will be used for compaction. |
Earth filling and excavation |
The
existing soil will be excavated by excavators while the general fill will be
placed by backhoes. After finishing the excavation and filling
works, the surface of soil will be further compacted by vibratory rollers. |
Construction of Bored Pile Foundation and Soldier
Pile Foundation for the Retaining Walls |
For the construction of retaining
walls with bored pile foundation, piling rigs will be mobilized to drill the
holes. The steel case will be inserted and the piles will be tremie concreted
by concrete pump. For the construction of retaining walls with soldier pile foundation,
piling rigs will be mobilized to drill the holes. The H piles will be
inserted and tremie grouting will be carried out. This
method is mainly used in site formation to allow minimise the change in the
groundwater hydrology connecting to the wet woodland. |
Construction of Reinforced Concrete (RC) L-shape
retaining walls for roads |
For
the construction of L-shape retaining wall, backhoes will be deployed for the
excavation of soil and then excavation lateral support will be installed for
temporary support against the pressure of soil. These two steps will be
repeated until reaching the formation level. After that, construction of the
L-shape retaining wall will be started and follow by the backfilling of soil
to the finish level. This retaining structure will be mainly used in road
widening work. |
Construction of soil nailing |
For the soil nailing
works, metal scaffolding will be erected and nail locations will be set out
on site. Drilling rigs will be
mobilized to form the holes and the steel reinforcement will be inserted.
Tremie grouting will be carried out and the sprayed concrete will be applied
on the nail heads. Where applicable, the construction method of soil nail is faster
and causes less environmental impact compared to other retaining
structures. |
3.4.2.6
For the construction of retaining walls for site platform in
particular, the foundation design has considered the use of D-wall or pipepiles.
However, the use of D-wall or pipepiles may affect the groundwater hydrology to
the wet woodland. Therefore, the use of bored piles for the retaining wall has
been selected to allow passage of groundwater to the wet woodland. More details
have been discussed in Section 6.5.
3.4.3
Widening of Sha Ling Road & Internal Roads
Sha Ling Road
3.4.3.1
In order to fully utilize the existing Sha Ling Road, about 900m of the
existing Sha Ling Road (approximately 3m wide) would need to
be widened. That section will be widened to a single
two-lane carriageway with a width of 7.3m and with a 3m footpath
on both sides as the main access to the Columbarium site (except the portion
beside the pick-up / drop-off area which is single two-lane carriageway with 4m
footpath on both sides).
3.4.3.2
Vehicular traffic can then access the
Columbarium site via the internal road, which is also designed as single
two-lane carriageway with 2m to 4m footpath on both sides.
3.4.3.3
Both the widening of Sha Ling Road and the internal roads would
require site formation, cut-&-fill and slope retaining structures. The
construction methodology would be similar to those for the site formation work
for the platform although the scale of work involved would be less extensive.
3.4.3.4
For the at-grade section of Sha Ling Road in particular, the existing ground level will
be excavated to the soffit level of proposed manhole. The manhole will be constructed and the pipe
will be laid after the completion of excavation. Subsequently, backfilling with
granular sub base and bituminous material will be carried out by excavator and
road grinder.
3.4.3.5
It should be noted that part of Sha Ling Road would require the
installation of noise barrier as a noise mitigation measures to abate road
traffic noise (see Section 5). The total length of the proposed noise
barrier is approximately 185m. These noise barriers would involve using concrete
footings or mini-piles for the foundation and light weight panels installed to achieve
the designated height. According to the
requirements in Guidelines on Design of Noise Barrier by Environmental
Protection Department and Highways Department in 2003, the lower portion of the
noise barriers would be installed with sound absorptive panels.
3.4.3.6
For the foundation of using mini-piles, piling rigs
will be mobilized to drill the holes first. After that, the existing ground level will be excavated to
the formation level of footing by backhoes. If there are proposed underground
utilities, they will be installed before backfilling soil. After laying underground
utilities, soil compaction by vibratory rollers would be carried out after soil
backfilling. Finally the noise barrier will be installed by mobile cranes.
Internal Roads
3.4.3.7 The upgrading of an existing short section of Sha Ling Road to MacIntosh Fort and the proposed roundabout as turnaround facility for vehicles is considered necessary. The internal roads with dead end aligned on the slope near the proposed open car park are emergency vehicular access (EVA) for the columbarium buildings, and EVA is required according to Architectural Services Department’s (ArchSD) design standard to comply with the Code of Practice for Fire Safety in Buildings.
3.4.4
New Road connecting Crematorium Site and Man Kam To Road
3.4.4.1
A new road junction at Man Kam To Road will
be formed to allow the vehicular access to the Crematorium site via the at-grade road and a
new viaduct, which will link to the internal loop surrounding crematorium and
funeral parlour. This new road is designed as single two-lane carriageway with
7.3m in width and 2m footpath on both sides.
3.4.4.2
For the at-grade section, the existing ground level will be excavated
to the soffit level of proposed manhole.
The manhole will be constructed and the pipe will be laid after the
completion of excavation. Subsequently, backfilling with granular sub base and
bituminous material will be carried out by excavators and road grinders.
3.4.4.3
For the viaduct section which is
approximately 300m long, the existing ground level will be excavated to the
soffit level of footing by excavator. Drilling will be carried out by piling
rig or earth auger. The mini piles or bored piles would be adopted. The pad
footing will be constructed and concreted by concrete pumps. Steel
reinforcement of column will be fixed with concrete casted in-situ by concrete
pumps. The falseworks and formworks will be installed and the decking will be
constructed afterwards by in-situ concreting.
3.4.5
Pick-up and Drop-off Point at Man Kam To Road
3.4.5.1
A pick-up
and drop-off point for the mini-buses, taxis and private cars is proposed at
Man Kam To Road as these vehicles are not allowed to go uphill during the
festive periods.
3.4.5.2
Site clearance will be carried out to remove
the obstruction.
After that, the existing concrete paving will be broken and then soil
excavation to the formation level will be carried out. The proposed underground
utilities and sewage will be installed and finally, backfilling
with granular sub base and bituminous material will be carried out by excavators
and road grinders.
3.4.6
Widening of Lin Ma Hang Road
3.4.6.1
The existing Lin Ma Hang Road is approximately 6m wide and will need
to be widened to single two-lane carriageway with 7.3m in width and a 2m footpath on
both sides. However, Lin Ma Hang Road does not involve
site formation instead it only involves minor slope works.
3.4.6.2
The existing ground level will be excavated
to the soffit level of proposed manhole.
The manhole will be constructed and the pipe will be laid after the
completion of excavation. Subsequently, backfilling with granular sub base and
bituminous material will be carried out by excavator and road grinder.
3.4.6.3
Apart from the roadwork, the construction of Lin Ma Hang Road may involve some
construction of retaining structures. The size of retaining structure is
relatively small compared to that of site formation at Sandy Ridge. Soil nail
will be mainly adopted as its construction method cause less disruption to traffic
and less environmental impact compared to other retaining
structure.
3.4.6.4
Similar to Sha Ling Road, some section of Lin Ma Hang Road will require
noise barrier to abate road traffic noise impacts on sensitive receivers in the
vicinity. The total length of the proposed noise barrier is approximately 400m.
These noise barriers would involve using concrete footings or minipiles for the
foundation and light weight panels installed to achieve the designated
height. According to the requirements in
Guidelines on Design of Noise Barrier by Environmental Protection Department
and Highways Department in 2003, the lower portion of the noise barriers would
be installed with sound absorptive panels.
3.5
Preferred Construction
Methodology – Works Outside Columbarium / Crematorium Site
3.5.1.1
There is a total of 4 pick-up / drop-off points outside the columbarium
/ crematorium site as mentioned in Section
3.1.1.2. Most of these pick-up / drop-off points would only require
temporary and minor modification to the current existing facilities. There
are permanent works proposed only at MTR Fanling Station and existing Sheung Shui Landmark North. For MTR Kwu Tung Station (including the PTI and shuttle bus services
area), it will be constructed under the Planning and Development
Study on North East New Territories (NENT) Contract and will be
available by 2026. The description and construction methods are presented in the sections below.
3.5.2
MTR Fanling Station
3.5.2.1
In order to provide adequate bus lay-bys for pick-up
and drop-off, some of the existing planters
on Fanling Station Road and San Wan Road need
to be removed to provide sufficient area for shuttle bus boarding /alighting. In addition, to avoid blockage of lane due to any broken
down bus, the physical barriers at the
Fanling Station Road pickup point will be demolished to provide ample room for
bypassing.
3.5.2.2
Besides, some of the existing planters on Fanling Station Road and
San Wan Road will be removed. The trees in the planters will be affected and
subject to the tree removal application to be submitted later. One backhoe and one hand-held
breaker will then be deployed to break the planter and the debris will be disposed
of by truck. Finally, the concerned area will be constructed as the pedestrian
footpath.
3.5.3
Sheung Shui Landmark North
3.5.3.1
It is noted that there is
an existing KMB bus route 73K serving grave sweepers between Sheung Shui and
existing Sandy Ridge Cemetery. It is proposed to provide a vehicular
opening connecting the Sheung Shui Landmark North PTI and Lung Sum Avenue to avoid the detour of bus
heading towards Man Kam To Road direction.
3.5.3.2
In order to achieve this, a portion of the
existing traffic island would need to be retrofit to allow for a new vehicular
opening. The road surface will then be reinstated by concreting.
3.5.4
Drainage, Sewerage, Waterworks and Utility Works
3.5.4.1
All the site formation works, road widening works, new road construction
etc. would inevitably require re-routing of existing drainage, sewerage, waterworks and utility
works.
3.5.4.2
The construction method of laying drainage, sewage, waterworks and
underground utility is similar. The
first stage will be to have trial pits to identify underground drainage and
underground utility. After that, the existing ground level will be excavated to
the formation level of proposed drainage and underground utility. If the depth of trench is large (typically
deeper than 1.2m), necessary excavation lateral support (ELS) will be against
the pressure of soil. Installation of drainage will then be carried out after
flattening and clearing the formation level. Soil will then be backfilled by
backhoes and compacted by vibratory rollers. Finally, the concrete paving will
be reinstated
by concreting
3.5.5
Temporary Works Sites / Areas
3.5.5.1
In order to
minimise the potential disturbance and impact to the public and environment,
the major works sites / areas are typically located at the site of the
permanent works. To support the construction of the Project, additional
temporary works areas would be required within project boundary for the
provision of site office, storage of materials, utility, temporary traffic
management scheme, temporary accesses / bridges, silos and ground treatment.
The locations of works areas have been selected with consideration of their accessibility
and suitability for construction works and future permanent facilities. The EIA
report has included locations of the works sites / areas for the Project and
indicated the project boundary (as indicated in Figures 1.1
and 1.2) within
which minor activities / works for supporting the construction of the Project
may occur based on the latest information at the time of writing.
3.5.5.2
As mentioned in Section 1.3 and shown in
Figure 1.3, a barging point is added and is
located off-site along Tsing Fat Street in Tuen Mun. The site is being utilised
as an existing barging point, no maintenance dredging and no night time
operation are anticipated. Minor construction works for the tipping halls and
new ramps are required.
3.5.5.3
Subject to actual site conditions and
constraints, minor preparatory works could also be required to be conducted in
and around the project boundary indicated in the EIA report. However,
these would only be short-term without inducing major environmental
implications to nearby sensitive receivers. With the implementation of
appropriate standard control measures and good site practices for construction
works, no adverse environmental impact would be anticipated.