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 RoadHarcourt RoadGloucester 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([1]).

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


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.


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


Year of Construction

Nature of Project


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





([1])   Maunsell Consultants Asia Ltd. (1999).  Agreement No. CE 74/98, Wan Chai Development Phase II Comprehensive Feasibility Study, Trunk Road Options Study, Trunk Road Options Report.