2.
PROJECT DESCRIPTION
2.1
Project Location
2.1.1
The proposed CWB & IECL is a trunk
road that connects Rumsey Street Flyover Extension (Route 7) and Island Eastern
Corridor (IEC) (Route 8) to form an east-west strategic route along the Central
and Wan Chai Reclamation (Figures 2.1).
2.2
Development Requirements, Scope and
Benefits
Requirements and Benefits of
the Trunk Road
2.2.1
The CWB and IECL were planned under
the Central and Wanchai Reclamation Feasibility Study (1989). The proposed trunk road has the following
requirements and benefits:
·
to relieve the existing main east-west
route (that is, Connaught Road
– Harcourt Road – Gloucester
Road) on the north shore;
·
to provide access to the Hong Kong
Convention and Exhibition Centre (HKCEC) Area and neighbouring areas being
developed as part of the reclamation schemes; and
·
to serve the additional traffic to be
generated by the developments on the Central and Wan Chai Reclamation.
Scope of the CWB & IECL
2.2.2
The scope of the CWB includes:
·
an
interchange (The Central Interchange) with slip roads to the distributor road
system on the Central Reclamation Phase I (CRI);
·
a dual
three-lane trunk road tunnel approximately 2.3 km in length between Central and
Causeway Bay forming the Central – Wan Chai Bypass, with an eastbound exit (the
Slip Road F Tunnel) to the HKCEC Extension;
·
two separate two-lane single-way tunnels around 0.7 km in length from
the HKCEC Area to Causeway Bay forming the Wan Chai Bypass;
·
tunnel
control buildings, ventilation buildings, operations areas and operation,
maintenance and recovery vehicles.
2.2.3
The scope of the IECL includes:
·
a dual four-lane trunk road about 1 km in length linking the CWB and
the IEC;
·
slip roads
from the trunk road connecting to Victoria Park Road and Hing Fat Street;
·
realignment
of the Victoria Park Road eastbound and provision of road connections to the
reclamation area;
·
associated road lighting, road signing, traffic control and surveillance
systems.
2.3
EIA Study Area
2.3.1
The following definitions of the study
areas were adopted with reference to the Brief for CWB & IECL:
·
Air
Quality Impact Assessment: The boundary
of the Study Area is about 500 m outside the boundary of the CWB & IECL
site;
·
Noise
Impact Assessment: The boundary of the
Study Area is about 300 m outside the boundary of the CWB & IECL site; and
·
Landscape
and Visual Impact: The boundary of the
Study Area for Landscape Impact Assessment should include all areas within 500
m outside the boundary of the CWB & IECL site, while the Study Area for the
Visual Impact Assessment should be defined by the visual envelope.
2.4
Project Design
Evaluation of Various
Alignment Options
2.4.1
The road layout within CRI and CRIII
that was proposed under the CRIII project had been endorsed by relevant
Government departments. Besides, there are some constraints which limit other
alternative alignments and structural arrangements along the West Section of
the Trunk Road. The constraints include the committed developments within CRI
such as the Airport Railway Hong Kong Station development, the connection with
the existing Rumsey Street Flyover and the as-built substructure of the Rumsey
Street Flyover Extension in CRI area. In CRIII area, the need of constructing the
Trunk Road in the form of tunnel is to optimise the proposed land uses and
minimise the extent of reclamation. The need of constructing the tunnel through
the existing water channel at HKCEC whilst maintaining a reserve for North Hong
Kong Island Line (NHKIL) of MTRC is another constraint. As a result, possible
alternative alignments and structural arrangements along the West Section of
the Trunk Road are limited. For the East Section of the Trunk Road, a Trunk
Road Option (TRO) study was undertaken under the WDII project to determine the
optimum road alignment and built form for the section of CWB extending from the
east limit of CRIII to the IEC to accommodate current planning intentions. All practicable options of elevated,
at-grade, underground and underwater alignments and forms of structure for the
Trunk Road, within the physical and planning constraints of the study area,
were considered. Eight options were
developed and evaluated against agreed performance criteria under the TRO
study, namely:
·
Option A – Tunnel and Flyover Scheme (Figure 2.5);
·
Option B – Flyover Scheme (Figure 2.6);
·
Option C – Flyover Scheme with Alignment close to the Shoreline (Figure
2.7);
·
Option D – Flyover Scheme with Alignment along the Breakwater (Figure
2.8);
·
Option E – Tunnel Scheme with Alignment close to the Shoreline (Figure
2.9);
·
Option F – Cut and Cover and Tunnel Scheme with Alignment close to the
Breakwater (Figures 2.10 and 2.11);
·
Option F1 – Immersed Tunnel Scheme (Figure 2.12); and
·
Option G – At Grade Road Scheme (Figure 2.13).
2.4.2
Descriptions of the alignments of
these options are attached in Appendix 2.1 of this EIA Report.
2.4.3
In the TRO Study, the environmental
performance of various alignment options are evaluated under the following criteria:
·
noise;
·
air quality;
·
water quality;
·
ecology;
·
sediment quality / waste;
·
land contamination;
·
minimisation of potential collective impact on visual receivers; and
·
minimisation of impact on landscape character and direct impacts on
specific landscape resources.
2.4.4
The initial environmental assessments
of various options were presented in the Trunk Road Options Report().
2.4.5
Based on evaluation of the 8 options
against agreed performance criteria including extent of reclamation,
engineering considerations, traffic requirements, planning aspects,
environmental impacts and costs, three schemes (Options A, D and G) were
considered to perform well and were selected for further assessment and
evaluation against land use planning opportunities. The full tunnel options
which were also considered were found not to be feasible on the grounds of
engineering and construction risk, risk of damage to the Cross Harbour Tunnel,
inability to meet road connectivity requirements, costs and operational risks.
2.4.6
Under the land use assessments
associated with the three options, key planning elements comprised:
·
the adoption of a marine theme for the waterfront development;
·
the extension of Victoria Park to the waterfront;
·
the creation of a waterfront to international standard.
2.4.7
The development proposals were
presented through a public consultation process in early 2000, including a
Public Consultation Forum that was held on 1 February 2000, in which views on
the proposals were obtained from a wide range of interested and concerned parties. A Consultation Digest presented the three
Trunk Road options selected as suitable for further evaluation and described
the land use concepts developed for these three options. At all stages of the consultation process,
Option A was supported over the alternative options as, in overall terms, the
land use proposals associated with the Trunk Road Option A were considered to
offer the optimal land use strategy, with the minimum extent of reclamation.
2.4.8
The preferred option, Option A, is a
tunnel and flyover scheme in which the western and central sections of the
Trunk Road are in tunnel, rising at the Wanchai Public Cargo Working Area
(PCWA) to cross over Kellett Island and remaining on elevated structure through
the eastern section, behind the Causeway Bay Typhoon Shelter, before connecting
to the existing elevated structure of the IEC.
Slip road connections and ground level roads provide access to the local
road network and adjacent development and facilities.
2.4.9
During the public consultation
process, although Option A was generally considered to provide an attractive
environment that would be a significant improvement over the existing
situation, a number of concerns were nonetheless raised. These focused mainly
on the following issues:
·
The extent of reclamation should be kept to a minimum.
·
Sufficient accesses to the waterfront should be provided.
·
The need for proposed facilities should be reviewed.
·
Environmental impacts of the proposal should be addressed, especially water
quality and elimination of ‘dead’ corners in the typhoon shelter and adjacent
to the Hong Kong Convention and Exhibition Centre.
2.4.10 In response to these concerns, a number of modifications were made
to the Option A layout. The Harbour Park was cause for particular concern with
regard to the extent of reclamation, and the Option A scheme was therefore
modified by omitting the Harbour Park but widening the yacht club marina
breakwater instead to enable better public access to the Harbour. In developing
the shoreline configuration, sharp corners and areas of slack water were
eliminated wherever possible to mitigate against poor water quality concerns.
2.4.11 The currently proposed Trunk Road and land use layout has been
derived with due consideration of all physical, geometric and operational
constraints, and was subjected to a comprehensive evaluation of planning,
engineering, traffic, environmental and cost considerations. The alignment and form of construction
presented represent the best feasible and practicable manner in which the Trunk
Road can be extended from Central to connect to the elevated IEC to the east of
the Causeway Bay Typhoon Shelter. The
proposed scheme offers the most efficient and balanced land use arrangement in
association with the Trunk Road.
2.4.12 The entire CWB & IECL was then subjected to detailed planning,
engineering, traffic and environmental assessments, to establish its
feasibility with the existing environment and the proposed WDII development.
Optimisation of Ventilation
Building Locations and Land Take
West Ventilation Building (Figure 2.1)
2.4.13 The primary function of the West Ventilation
Building (WVB) is to extract vitiated air from the tunnel before reaching the
west exit portal. It is important the building is located close to the portal
to avoid ducting of the pollutants. Due to land use constraints around the
portal area, available land is in short supply at the west portal as there are
a number of major developments associated with the Airport Railway and the
ferry piers. The most suitable location of the WVB was found to be directly
above the west portal itself. The
floor areas for the rooms of WVB are provided according to the latest
ventilation and power requirements for the proposed dual 3-lane tunnel. For
site planning of the building, the ground floor footprint has been minimized
according to the limited site area.
Central
Ventilation Building (Figure 2.1)
2.4.14 Originally two proposals were made for the ventilation of Slip Road
F and the west bound short tunnel. The
first proposed separate buildings (Portal Exhaust Building and Mid Tunnel
Ventilation Building, situated adjacent to the Slip Road F Tunnel and
Convention Avenue respectively). The
second option combined these two elements into one Central Ventilation Building
(CVB) in designated Open Space in the Central and Wanchai Reclamation
Area. The latter proposal was
recommended as the preferred option due to its reduced visual impact and land
take.
East Ventilation Building and Administration
Building (Figure 2.1)
2.4.15 The East Ventilation Building (EVB) is located
close to and above the East Portal.
Sizing requirements for the rooms within the EVB accord with the latest
ventilation and power requirements for the proposed dual 3-lane tunnel. The function of the building is similar to
WVB, removing vitiated air from the eastbound long and short tunnels. The
Administration Building (ADB) is located at the same place and on the upper
floor of EVB. The ADB building included the tunnel control rooms as well as the
administration, catering, recreational facilities for the tunnel operation
staff. The size of the available site which can only accommodate one building
due to site constraints such as a large drainage reserve to the eastern end of
the site. The provision for a possible future road at the western end of the
site also restricts the possible arrangement of the building. After reviewing the site and requirements of
the two buildings, it has been proposed to combine the two buildings into one.
The areas dictated for the plant, workshops and parking, and ground level
access requirements, take up all the available buildable site area. The Administration Building above forms a
‘bridge’ over the drainage reserves. Combining the buildings has the advantages
of more efficient site usage, combination (and, therefore, reduction in
provision) of items such as circulation elements and some plant room areas and
a reduced visual impact as only one building form is constructed rather than
two separate elements.
Current Design
2.4.16 The proposed CWB & IECL includes the followings:
·
ground level dual 3-lane trunk road and slip roads at the CRI;
·
dual
3-lane CWB Tunnel extending from CRI, through CRIII, to the existing Wan Chai
Public Cargo Working Area;
·
two separate two-lane single-way tunnels extending from HKCEC Area to
Causeway Bay forming the Wan Chai Bypass;
·
slip
roads on the elevated structure connecting to the Victoria Park Road and Hing
Fat Street;
·
the Satellite Control Building located at the CRI near the Rumsey
Street Flyover;
·
the West Ventilation Building located at the CRI near Man Po Street;
·
the
Central Ventilation Building located at WDII near the Hong Kong Convention
& Exhibition Centre Extension; and
·
the
East Ventilation Building and Administration Building located at the eastern
end of the CWB tunnel portal near the existing Wan Chai Public Cargo Working
Area.
2.5
Construction Methods and Engineering
Requirements
Elevated Structures
2.5.1
The elevated structure of the Central
Interchange at CRI will be a post-tensioned in
situ concrete structure. The
central support will provide the fixity, the deck being built into the column.
2.5.2
The bridge decks of the IECL will
generally be prestressed concrete box sections constructed either in situ or utilising precast segmental
techniques, spans are typically in the range of 40 m to 45 m except a 58 m long
span bridge proposed above the portal of Cross Harbour Tunnel at Causeway Bay.
At the transition to the IEC, precast U-beam will be adopted for the bridge
deck to match with the existing structural configuration. The bridge edge
parapet will be reinforced concrete with aluminium top rail. The external parapet face will be curved and
recess will be added to enhance the visual effect. The edge parapet will be sufficiently deep to mask drainage gully
sumps.
2.5.3
Modifications of the IEC are also
required, including:
·
removal of a portion of the existing IEC between abutment in Victoria
Park Road and IEC piers;
·
removal of the existing up ramp
from Hing Fat Street to IEC eastbound;
·
widening
of the existing structure between IEC piers. The proposed widening works will
be of similar structural form to the existing structure with U-beam / in situ concrete decks supported on
crossheads and columns;
·
reconstruction
of IEC span to provide a connection between the new and existing
structures. The reconstruction will
utilise a U-beam deck similar to the existing.
Tunnel Box
2.5.4
The tunnel box at CRIII and WDII will
be constructed in conjunction with the associated reclamation works and will
include diaphragm wall for the permanent tunnel walls and bottom up
construction for the tunnel slabs.
Where the tunnel cross beneath culvert at CRIII and WDII, the tunnels
will also be supported by diaphragm walls.
2.5.5
Where the tunnel crosses the existing
immersed tube Mass Transit Rail (MTR) lines and diaphragm walling cannot be
used, precast sections of the tunnel will be floated into position. Piled foundations will be constructed on
each side of the MTR tubes with the section of Trunk Road Tunnel spanning
between them.
2.5.6
At the Central Interchange, diaphragm
walling is proposed for tunnel walls.
The tunnel box will then be constructed top down in order to reduce
propping requirements and to allow roads to be reinstated over the tunnel at
early stage.
2.6
Operation of the Project
2.6.1
The proposed CWB & IECL will be
managed by Transport Department with the tunnel area operated by a private
company. The tunnel operating company
will be responsible for cleaning, maintenance and traffic control. Transport
Department and Electrical and Mechanical Services Department will monitor
tunnel operation.
2.7
Works Programme
2.7.1 Some of the works of the CWB & IECL will
be constructed on land reclaimed under TDD’s CRIII and WDII projects. In order
to minimise the construction interface with these projects, the construction of
tunnel box structure within the CRIII and WDII areas are entrusted to TDD’s
CRIII and WDII project respectively.
Apart from the entrusted works, the works of the CWB & IECL will be
divided into three work packages and constructed by HyD’s contractors. All work packages for the CWB & IECL are
summarised as follows:
·
Entrusted Works in CRIII Area
·
Entrusted Works in WDII Area
·
Central Interchange
·
IEC Link
·
Tunnel Building, E&M Installation and
Ancillary Works
2.7.2 The construction of
the Project will commence in March 2004 and complete in February 2012. Figure 2.14 shows the construction programme
of the Project.
2.8
“Without the Project” Scenario
Traffic
2.8.1
Without the CWB & IECL, the
east-west strategic corridors of the hinterland such as Gloucester Road, Harcourt Road and Connaught
Road Central will be severely affected. This will have a knock-on effect on
Hennessy Road and Queen’s Road East and Central. The north-south links to the Gloucester Road corridor will also be
affected. At the eastern end of the CWB
& IECL, long queues would be anticipated along the IEC as Victoria Park
Road between Gloucester Road Flyover and Canal Road, already very congested,
will become a bottleneck. At the
western end, Connaught Road Central (between City Hall and Furama Hotel) will
be severely congested. Road connections
to the proposed Road P2 under CRIII from the hinterland will also not be able
to operate due to congestion.
2.8.2
In summary, from traffic point of
view, given that the existing east-west corridors along the north shore are
already overloaded at the present, the future increase in cross harbour traffic
as well as general traffic growth on the island due to SAR-wide population and
employment growth will exert additional pressure on the existing road network,
thus causing further congestion and likely ‘gridlock’ situations to the north
shore of Hong Kong Island, which may also have far reaching impacts to the
harbour crossings.
Planning
2.8.3
Under the provisions of the Protection
of the Harbour Ordinance, land formation can only be generally justified if it
is to support the development of required infrastructure (that is, roads,
etc). Should the CWB & IECL not be
developed the requirement for land formation is likely to fall away. Reclamation would only occur if Government
were to decide that the public good would not be served if reclamation were not
to be implemented. Current
institutional mechanisms may mitigate against the realisation of reclamation in
such circumstances.
2.8.4
Under the assumption that the CWB
& IECL is not built and that land formation does not take place the
following scenarios are likely:
·
The existing pattern of land use will remain broadly unchanged.
·
No new land will be available to upgrade and improve the waterfront.
·
It
will be extremely difficult to respond to the Town Planning Boards stated
objectives for waterfront areas abutting the Victoria Harbour (“Vision and
Goals for Victoria Harbour” Town Planning Board October 1999). These are principally associated with
enhancing public access to the waterfront and providing waterfront recreational
spaces comparable with international standards.
·
The
volume of traffic on the existing road network will increase
substantially. This will deteriorate
the environment within spaces currently adjacent to the waterfront. The usability of the waterfront will decline
correspondingly.
·
Opportunities to upgrade the waterfront east of the HKCEC Extension
would be undermined (the design of the HKCEC Extension assumed that such areas
adjacent would be upgraded and improved).
·
Without
the land formation associated with the CWB & IECL it may be difficult to
rationalise existing land use.
·
The
absence of the CWB & IECL may limit the capacity of the road network generally
placing a further constraint on optimising the development potential of sites
in the vicinity of the CWB & IECL alignment and possible sites elsewhere on
Hong Kong Island.
2.8.5
Conversely, a decision not to
construct the CWB & IECL, would have the following benefits:
·
Visual
and physical impacts resulting from trunk road related structures would be
avoided.
·
The
physical impact of ground level roads associated with the CWB & IECL on the
existing land use would be avoided.
2.8.6
In summary, from a planning perspective,
should the proposed CWB & IECL not be constructed, opportunities to improve
the existing waterfront would be limited.
Under this condition, material enhancement of the waterfront would be
unlikely. Negative consequences would
predominate.
2.9
Concurrent Projects
2.9.1
The proposed CRIII and WDII will
provide land for the CWB & IECL.
They will be constructed concurrently with the Project (Table 2.1).
Table 2.1 Projects that may be
Undertaken Simultaneously with the CWB & IECL Project
|
Project
|
Year of Construction
|
Nature of Project
|
Remark
|
|
Central Reclamation Phase III (CRIII)
|
Aug 2002 – Mar 2007
|
Roadworks and infrastructural
developments
|
Construction of the CWB tunnel box within
CRIII will be entrusted to a CRIII contract
|
|
Wan Chai Development Phase II (WDII)
|
Mar 2004 – Feb 2010
|
Roadworks and infrastructural
developments
|
Construction of the CWB tunnel box within
WDII will be entrusted to a WDII contract
|
|
Causeway Bay Flyover
|
May 2003 – Feb 2006
|
Roadworks
|
-
|