List of Tables
Project is located mainly in Wan Chai North,
study area encompasses existing developments along the Wan Chai,
Quality Impact: the assessment area should include the area within
Impact Assessment: the assessment area should include the area within
Quality Impact Assessment: the assessment area should include the areas within
and Visual Impact: the area for
landscape impact assessment should include all areas within
the Project, permanent reclaimed land will be formed along the existing Wan
Chai and North Point shorelines for the construction of the Trunk Road. At the same time, an attractive
waterfront with a new public promenade will be provided. A total reclamation area of
2.3.2 In reviewing the change of scope and extent of the elements of the Project from what was originally proposed, and which was covered by the approved WDIICFS and CWB&IECL EIA Reports under the EIAO in 2001, the changes are confined to the nature and extent of the Trunk Road and associated ground level roads, Road P2, and the extent of reclamation. As the original schemes for the cross-harbour water mains and the sewage outfall have not changed materially, the related EIA assessments of the approved EIA Report for the WDIICFS for these works remain valid. This EIA study focuses mainly on those elements of the Project that have changed significantly from the schemes as presented in the approved EIA Reports. For the dredging for the cross-harbour water mains and the sewage outfall, this EIA Study has still included the cumulative impact assessment, updated the assessment assumptions and the corresponding mitigation measures.
2.3.3 The extent of the Trunk Road covered by the approved EIA Report on the CWB & IECL includes the Central Interchange in Central Reclamation Phase I (CRI), the Trunk Road tunnel that runs through CRIII and partly through WDII (extending to the location of the ex-PCWA basin), and the IECL through WDII connecting the Trunk Road tunnel to the IEC at the eastern end of the CBTS. It should be noted that it is only the section of the Trunk Road through WDII that is subject to change under the WDII Review. As the original scheme for the Trunk Road through CRI and CRIII has not changed, findings and recommended mitigation measures of the approved EIA Report for the Trunk Road within the CRI and CRIII areas remain valid. The relevant environmental findings and recommended mitigation measures are captured from the approved EIA Report and summarised below.
EIA study is confined to the elements that have changed significantly from the
scheme as presented in the approved EIA Report for the CWB&IECL, viz. the
Trunk Road tunnel through WDII and its connection to the existing IEC (Figure 1.1). A comparison table comparing the original
scheme of WDII and CWB under the approved EIA Report on Wan Chai Development
Phase II (Application No. EIA-058/2001) and on the Central-Wan Chai Bypass and
2.3.5 The previous key EIA findings, impact predictions and recommendations as stipulated in the approved CWB&IECL EIA Report are considered valid for the Central Interchange in CRI and the Trunk Road tunnel that runs through CRIII. The relevant implementation schedule of the proposed mitigation measures for the CWB within CRI and CRIII as extracted from the approved CWB&IECL EIA Report is given in Appendix 2.2.
The construction activities at Central Interchange and
CRIII remain the same as those given in the approved CWB&IECL EIA
Report. There will be tunnel,
bridge, tunnel building construction and demolition of part of Rumsey Street
Flyover at Central Interchange area.
There will be CWB tunnel construction at the CRIII area. The preliminary design of the
2.3.8 The existing air sensitive receivers from Sheung Wan through Central will be protected from adverse construction air quality impact by the recommended dust control measures during construction phase. The recommended mitigation measures for dust control include:
strictly limit the truck speed on site to below
2.3.9 With no increase in the proposed tunnel portals and ventilation building emissions, and the same traffic pattern at the Central Interchange area, the air quality assessment from the previous CWB&IECL approved EIA is still valid for the operation phase. No adverse operational air quality impacts at the existing and planned air sensitive receivers from Sheung Wan to Central are predicted and mitigation measures are not considered necessary. For the air pollution within the tunnel section in CRIII, monitoring of tunnel air quality will be required to ensure the acceptability of the tunnel air quality criteria.
2.3.10 The existing noise sensitive receivers from Sheung Wan through Central, including Korea Centre, City Hall and PLA Headquarters, will be protected from adverse construction noise impact by the recommended noise mitigation and control measures during construction phase. The mitigation measures during construction phase include:
demolition of downramp of
2.3.11 For the operation phase, no direct noise mitigation measures are required from Sheung Wan to Central for the three noise sensitive receivers, Korea Centre, City Hall and PLA Headquarters for the new trunk road and slip roads at Central Interchange. The Trunk Road in CRIII is in tunnel and no direct mitigation measures are required. The findings and recommendations of the approved CWB&IECL EIA Report in respect of noise are still valid.
As no reclamation will be undertaken directly for the
CWB at the Central Interchange (reclamation for the CWB through CRIII is
addressed in the approved CRIII EIA Report), the primary concern with regard to
water quality will be the control of runoff during construction. This could potentially contain elevated
constructions of suspended solids (SS), and could impact upon the flushing and
cooling water intakes located along the
2.3.13 Mitigation measures, including road drainage with silt traps and petrol interceptors, are also recommended to remove oil and grease from the road runoff during operation. No unacceptable residual water quality impact is expected. The findings and recommendations of the approved CWB&IECL EIA Report in respect of water quality are still valid.
2.3.14 Provided that waste arising from the construction of the CWB at Central Interchange and CRIII areas are handled, transported and disposed of using approved methods as recommended in the approved CWB&IECL EIA Report, and that no solid or liquid wastes enter nearby marine waters, no unacceptable environmental impacts are envisaged. These recommended methods include segregation of wastes, water minimization, and good site practices for storage, collection and transport of waste during construction. The estimated quantity of excavated material from the Central Interchange and west tunnel building are unchanged. The mitigation measures recommended in the approved CWB&IECL EIA Report should be incorporated into contract specifications to ensure that environmental nuisance will not arise from the storage, transport and disposal of various types of waste arising from the construction of the CWB project. These recommendations should form the basis of the site Waste Management Plan to be developed by the Contractor at the construction stage. The findings and recommendations of the approved CWB&IECL EIA Report in respect of waste management are still valid.
2.3.15 Key issues relating to the impact on the landscape and visual context of the proposed road include the loss of existing vegetation, the addition of infrastructure associated facilities (west ventilation building), associated works (portals, wing walls and abutments), and elevated road sections at Central Interchange and CRIII areas.
· Significant adverse residual visual impacts would occur along the CWB from buildings with a harbour outlook around the Central Interchange and CRIII areas. Moderate adverse impacts on visually sensitive receivers with distant views from Tsim Sha Tsui waterfront.
· The extended Rumsey Street Flyover and its associated elevated slip road are located further west from the proposed Central waterfront promenade. Thus, they have negligible residual landscape impact to the planned waterfront promenade.
· The Central area will have significant adverse residual visual impact at residential units at Shun Tak Centre. Moderate / significant adverse residual visual impact would occur at the Airport Railway Hong Kong Station Northern Site Development (the IFC and Four Seasons Hotel) due to the close view of the elevated road structures.
2.3.18 The overall residual landscape and visual impact after the implementation of the recommended mitigation measures will be moderate adverse. In the context of Annex 10 of the EIAO-TM, the landscape and visual impacts are considered acceptable with mitigation measures. The findings and recommendations in the approved CWB&IECL EIA Report in respect of landscape and visual impacts are still valid.
2.3.19 In summary, the relevant findings and recommendations of the approved CWB&IECL EIA Report for the CWB within the Central Interchange and CRIII areas have been reviewed and are found to be still valid.
The previously approved WDIICFS EIA Report covers a
Schedule 3 DP for an engineering feasibility study of an urban development
project with a study area covering more than
2.3.21 As the original schemes for the sewage outfall and cross-harbour water mains from Wan Chai to Tsim Shai Tsui have not changed, the related EIA assessments of the approved EIA Report for the WDIICFS for these works are therefore considered to remain valid.
As presented in paragraph 1.6 above, this WDII&CWB
EIA Report covers the Schedule 3 DP for an engineering feasibility study of an
urban development project with a study area covering more than
2.3.26 During reclamation, filling and surcharging were identified as the major dust sources and entrusted works of the CWB tunnel section would also cause potential dust nuisance during excavation and backing as stated in the WDIICFS EIA Report. This will also be the case for the revised scheme as identified in the WDII&CWB EIA Report and is incorporated in the air quality assessment in Section 3 of this report.
strictly limit the truck speed on site to below
The air quality assessment of the WDII&CWB EIA Report has considered the above recommendations and they are incorporated as mitigation measures to suppress dust during the construction phase where appropriate.
2.3.28 No adverse cumulative air quality impacts were predicted at the air sensitive areas for the operation phase in the WDIICFS EIA Report, after considering the background pollutant levels within and adjacent to WDII, vehicle emissions from open road networks, tunnel portal and ventilation building emissions from the CWB, tunnel portal emissions from the Cross Harbour Tunnel, and portal emissions from existing underpasses and planned deckovers. No mitigation measures were required under the WDIICFS EIA Report.
2.3.29 Air quality impacts are updated in the WDII&CWB EIA Report, which also considers on the background pollutant levels, vehicle emissions from open road networks, tunnel portal and ventilation building emissions from CWB, tunnel portal emissions from existing tunnels, underpasses and planned deckovers with updated and latest available data in assessing the cumulative air quality impacts. Findings of the air quality assessment are given in Section 3 of this report.
2.3.30 WDII construction noise impacts were predicted taking into account other concurrent projects including the CRIII and CWB&IECL projects and the Causeway Bay Flyover project in the WDIICFS EIA Report. As the Causeway Bay Flyover project has already been completed, the current WDII&CWB EIA Report has not included the Causeway Bay Flyover project as a concurrent project.
2.3.31 It was given in the WDIICFS EIA Report that, with the use of silenced equipment and movable barriers for WDII construction tasks and implementation of the noise mitigation measures proposed in the CRIII and CWB&IECL EIA Reports, the noise levels at all residential noise sensitive receivers (NSRs) would comply with EIAO-TM construction noise criteria during normal daytime working hours, with mitigated noise levels being in the range of 60 to 75 dB(A). Some noise exceedences of 4 to 7 dB(A) were still predicted at the Performing Art Centre and at the HKCEC Extension. However, these NSRs are equipped with central air-conditioning systems and good noise insulation facilities, and they do not rely on openable windows for ventilation. No adverse noise impacts were therefore expected for the indoor environments of these NSRs.
2.3.32 An indicative assessment was undertaken in the WDIICFS EIA Report for possible construction activities during restricted hours (1900 to 2300) associated with the reclamation works of the Project. With the reduction of plant numbers, adoption of quiet plant and reduction of on-time percentage for some equipment, the predicted noise levels at all representative residential NSRs would comply with the construction noise criterion of 65 dB(A). Noise exceedences of the 65 dB(A) criterion at HKCEC were still predicted at certain periods, for plant working close to the HKCEC Extension. The results of the construction noise impact assessment for restricted hours (1900 to 2300) were for indicative purposes; the Noise Control Authority will process any CNP application, based on the NCO and the relevant technical memoranda in addition to considering the contemporary situations / conditions.
2.3.33 The construction noise impact assessment has been updated for the revised scheme. The current WDII&CWB EIA follows similar principles adopted in the WDIICFS EIA Report and reduction of plant numbers, adoption of quiet plant and reduction of on-time percentage for some equipment are also adopted in the WDII&CWB EIA. Findings of the updated construction noise impact assessment for the WDII&CWB EIA are given in Section 4 of this report.
2.3.34 In the WDIICFS EIA Report, the potential road traffic noise impacts were assessed for the worst-case traffic flows in 2027. No adverse traffic noise impacts were expected and no operational mitigation measures were proposed for the WDII roads. No adverse impact from helicopter noise and fixed noise sources including ventilation shaft noise from the CWB ventilation buildings were anticipated at the existing and planned NSRs.
the WDII&CWB EIA Report, the potential road traffic noise impacts are
assessed for the worst-case traffic flows in
2.3.36 The water quality impacts during the reclamation of WDII were quantitatively assessed by numerical modelling in the WDIICFS EIA Report. Suspended sediment was identified as the most significant water quality parameter during the reclamation. The worst-case scenarios during reclamation, taking into account the anticipated reclamation stages and possible overlapping dredging and filling activities, were assessed. The assessment also took into account the cumulative effects that arise from the adjacent CRIII reclamation and other concurrent reclamation works in the harbour. It was predicted that potential water quality impacts could occur at seawater intakes along the Central and Wan Chai shorelines and in the CBTS, with a maximum concentration of suspended solids (SS) at the surface layer up to 263 mg/l. However, the water quality impacts at the seawater intakes can be effectively minimised with the implementation of proposed mitigation measures, which include silt curtains around the dredging operations, silt screens at the intakes and bulk filling behind constructed seawalls. Maximum surface SS levels at the seawater intakes would be less than 30 mg/l after the implementation of these measures and there would be no residual adverse water quality impacts due to the WDII reclamation and due to the cumulative effects from other concurrent reclamation activities.
2.3.37 Suspended sediment is still identified as the most significant water quality parameter during the reclamation in the WDII&CWB EIA Report and numerical modelling is also adopted for the quantitative assessment for water quality impacts during reclamation of WDII. Similar mitigation measures, including silt curtains around the dredging operations and silt screens at the intakes, will be applicable for the WDII&CWB EIA Report. The construction phase water quality assessment based on the updated reclamation sequence and concurrent reclamation works at the harbour for the WDII&CWB EIA is given in Section 5 of this report.
2.3.38 Water quality impacts from land-based construction, including road works, waterfront facilities and public utilities, are associated with the surface runoff, effluent discharge from the site and sewage from on-site construction workers. Impacts can be controlled to comply with statutory standards by implementing mitigation measures such as on-site drainage and sediment traps to control run-off. No unacceptable impact on land-based water quality impact was anticipated in the WDIICFS EIA Report. The water quality impacts from land-based construction would be similar for both the WDIICFS EIA Report and the WDII&CWB EIA Report. Findings of the WDII&CWB EIA Report shall refer to Section 5 of this report.
2.3.39 An assessment of the hydrodynamic impact due to the WDII reclamation, including the adjacent CRIII reclamation, was undertaken for the coastline configuration in the WDIICFS EIA Report. Potential impacts to tidal flows were assessed by comparing the baseline and operation phase conditions. It was concluded in the WDIICFS EIA Report that the WDII reclamation will have minimal impact on the hydrodynamic regime in the study area. With the extent of reclamation substantially reduced, the impact on hydrodynamic regime for the WDII&CWB EIA would be minimal as compared to WDIICFS EIA. Assessment of the hydrodynamic impact due to the latest coastline configuration is included in the WDII&CWB EIA Report and the findings are presented in Section 5 of this report.
assessment of the water quality impacts during the operation of WDII was also
undertaken in the WDIICFS EIA Report.
Comparison between the baseline and operational water quality modelling
results suggested that the levels of pollutants near Wan Chai and the neighbouring
areas were similar under both baseline and operational scenarios. No unacceptable impacts associated with
the operation of WDII upon the water quality in
the WDIICFS EIA Report, the total volume of dredged sediment for the WDII
reclamation was estimated to be approximately
2.3.42 For the revised scheme, the total volume of dredged sediment, including the quantities of Category H contaminated sediments, is updated and presented in Section 6 of this report. The use of geosynthetic containers for containment of the contaminated sediments before disposal at the contaminated mud pits are also proposed in the WDII&CWB EIA Report. The field trials as recommended in the WDIICFS EIA Report have already been completed and the findings are incorporated in Section 6 of the WDII&CWB EIA Report.
2.3.43 According to the WDIICFS EIA Report, wastes generated by construction activities would include construction and demolition (C&D) materials (including excavated material), general refuse and chemical waste. Provided that these identified waste arisings would be handled, transported and disposed of using approved methods and that the recommended good site practices as identified in the WDIICFS EIA Report were strictly followed, adverse environmental impacts were not anticipated. The C&D material should be sorted on-site into inert C&D material (ie public fill), for reuse in the reclamation, and C&D waste for recycling or disposal. The type of waste generated from the revised WDII and CWB projects would be similar to those of the WDIICFS but the quantities are updated with the increase in tunnel length. The updated assessment on waste management for the WDII&CWB EIA is given in Section 6 of this report.
2.3.44 The land contamination assessment in the WDIICFS EIA Report included a review of site history and existing environmental information, and a preliminary site inspection. Two possible contaminated land sites were identified: the A. King Marine shipyard in the CBTS and the boatyard area of the RHKYC. Potential contaminants arising from shipyard operations and the yacht club were identified, however, based on available information, the potential for land contamination in these areas was not considered to be insurmountable. It was proposed in the WDIICFS EIA Report that site investigation should be conducted prior to the commencement of site clearance / construction works.
2.3.45 For the new Trunk Road layout now proposed, the boatyard area of RHKYC will not be affected and it is no longer identified as a possible contaminated site in the WDII&CWB EIA Report. The site investigation at A King Shipyard as proposed in the WDIICFS EIA Report has been carried out and the findings are included in the WDII&CWB EIA Report. The updated land contamination assessment for the WDII&CWB EIA is given in Section 7 of this report.
ecological assessment in the WDIICFS EIA Report indicated that the marine
ecological resources within the WDII area were considered to be of low
ecological value. The dredging and
reclamation works would result in the permanent loss of approximately 28.5
hectares of soft bottom benthic habitat.
2.3.47 With the reduction in extent of reclamation, the permanent loss of soft bottom benthic habitat and artificial intertidal habitat under the WDII&CWB EIA are expected to be less than the WDIICFS EIA. Nevertheless, the marine ecological assessment has been updated under the WDII&CWB EIA and is given in Section 9 of this report.
2.3.48 In the WDIICFS EIA Report, organically enriched marine bottom sediment was planned to be left in-situ at the WDII reclamation within the western and eastern corners of the CBTS. As methane gas could be generated under anaerobic conditions, there was a potential for this gas to be released either during construction or after development of the reclaimed area. Assessment on impact of biogas emissions was included in the WDIICFS EIA Report, which concluded that with the incorporation of the recommended gas protection measures in the design of the developments and precautionary measures during construction activities, the risk to people and property due to biogas emissions from the WDII reclamation is considered to be low. However, as a fully dredged approach is adopted for the current project proposals and no more organically enriched marine bottom sediment is planned to be left in-situ at the WDII reclamation, assessment on biogas emissions is not included in the WDII&CWB EIA Report.
2.3.49 A landscape and visual impact assessment (LVIA) was conducted in the WDIICFS EIA Report to assess the impacts of the proposed developments within WDII, for both the construction and operation phases, on the surrounding area. Landscape and visual mitigation measures would be achieved principally through the realisation of a Master Landscape Plan encompassing the following objectives:
· the establishment of an integrated, pedestrian oriented streetscape which will enhance pedestrian movement, integrate the proposed and existing developments within an overall landscape framework and generally improve the quality of the public environment;
creation of a high quality
In the WDII&CWB EIA Report, the above objectives for landscape and visual mitigation have been considered in the development of the Concept Plan, RODP and Master Landscape Plan for the new project proposals.
2.3.50 As mentioned in the WDIICFS EIA Report, the ability to create a world-class harbour frontage, in respect of visual and landscape impacts, was somewhat constrained in the area adjacent to the IECL. This was due to the dominating visual presence of the IECL running through the reclaimed CBTS and also because a large landscape area would lie under the IECL at the newly formed land over the CBTS. However, in the WDII&CWB EIA Report, the Trunk Road will be below the existing seabed of the CBTS and the existing CBTS will be retained. There is no IECL running through the CBTS. The previous findings of the visual and landscape impacts of the IECL through the CBTS no longer apply; these are updated in the WDII&CWB EIA Report.
landscape impacts on street tree planting in Wan Chai North and on the
landscape character of the streets and open spaces in Wan Chai North and
visual impacts on the majority of buildings in Wan Chai, Wan Chai North and
2.3.52 For the operation phase, the WDIICFS EIA found that, after all mitigation measures have been implemented and have matured over 10 years, there would still be some residual adverse landscape and visual impacts, the most significant impacts being:
· Substantial visual impacts on the buildings in Wan Chai North which would have their harbour views blocked by the proposed CDA development, on buildings along Gloucester Road in Causeway Bay which would have their harbour views partially obscured by the proposed hotel / commercial development and which would also have clear views of the IECL, and on the Police Officers' Club which would be visually dominated by the IECL and the proposed hotel / commercial development.
2.3.53 However, for the new WDII and CWB project proposals, the Trunk Road will be in tunnel through the CBTS and no new major developments are proposed. Landscape and visual impacts are therefore substantially reduced. The revised LVIA for the new scheme is presented in Section 10 of this report.
2.3.54 Apart from the two EIA Reports for the WDIICFS and CWB&IECL mentioned above, there are also previous EIAO submissions, either associated with projects within the current Project boundary or that contain information relevant to the previous or current development schemes for the Project. The previously approved EIA for CRIII – Studies, Site Investigation, Design and Construction (Application No. EIA-055/2001) is one of the identified relevant EIA reports.
2.3.55 The previously approved CRIII EIA Report includes four Schedule 2 DPs with Environmental Permit (EP-122/2001) issued prior to commencement of construction. The relevant Schedule 2 DP is for the construction of the CWB within the CRIII area. As the original scheme for the CWB within CRIII has not changed, the EIA assessments of the approved CRIII EIA Report and the EP issued for the construction of the CWB within the CRIII area remain valid.
2.3.56 Some of the CRIII works will take place concurrently with the WDII and CWB works. With respect to the assessment of environmental impacts, the key indicators of air and noise will be influenced by the cumulative effects of the overlapping construction works. The concurrent activities and the cumulative environmental impacts have been assessed in the current WDII&CWB EIA Report.
concurrent dusty construction activities undertaken within
2.3.59 All the marine dredging activities for CRIII will be completed before the construction of WDII. No concurrent dredging activities for CRIII that will affect the water quality impact assessment of the WDII&CWB EIA are identified.
2.3.60 With regard to solid waste management, provided that the recommendations put forward in the previously approved CRIII EIA Report relevant to the construction of the CWB tunnel within CRIII are conscientiously acted upon, the storage, handling, collection, transport, and disposal of wastes arising from the construction of the CWB tunnel within CRIII will be in full compliance with the regulatory requirements.
2.3.61 The CWB tunnel will be entirely below ground for the section within CRIII. The CRIII EIA found that both the landscape and visual impacts within CRIII are acceptable with mitigation measures as described in category (c) of Annex 10 of the EIA-TM. The key mitigation measures recommended in the approved CRIII EIA Report are mainly for the open spaces and above ground structures, which will be implemented under the CRIII project. The findings and recommendations of the approved CRIII EIA Report in respect of landscape and visual impacts associated with the CWB within CRIII are still valid.
2.3.63 Some of the ALE works will take place concurrently with the WDII and CWB works. With respect to the assessment of environmental impacts, it is the key indicator of noise that will be influenced by the cumulative effects of the overlapping construction works. The concurrent activities and the cumulative environmental impacts have been assessed in the current WDII&CWB EIA Report.
2.3.65 During the operation phase of the WDII&CWB projects, the ALE will be in operation. The impact assessment for the operation phase of the WDII and CWB projects has taken into consideration the completed ALE.
2.4.1 The basis of the WDII project and the core transport infrastructure for which the project provides is the Trunk Road. The Trunk Road is defined from the connection with the existing Rumsey Street Flyover in Central, through to a connection with the existing IEC to the east of the Causeway Bay Typhoon Shelter. At the Rumsey Street Flyover connection, a Central Interchange will provide connections into the Central area, and then the Trunk Road will drop down into tunnel and run along the Central shoreline, through CRIII, to the WDII project area. In WDII, the Trunk Road will continue in tunnel until it needs to rise onto elevated flyover structure to connect with the elevated IEC. The section of the Trunk Road that runs in tunnel through CRIII and WDII is also known as the CWB, whilst the section of the Trunk Road on flyover, for the connection with the IEC, is also known as the IECL.
Trunk Road will form an east-west strategic route through Central and Wan
Chai. The Trunk Road is an
essential element of Government’s strategic transport planning for Hong Kong;
it is the “missing link” in the strategic highway running along the northern
2.4.3 The Trunk Road was originally proposed under the Central and Wanchai Reclamation Feasibility Study, completed in 1989, where its feasibility was established. The need for the Trunk Road was reaffirmed in the WDIICFS, completed in 2001, which demonstrated an urgent need for the link to be put in place in order to relieve the existing and growing congestion along the east-west corridor of Hong Kong Island North. A number of strategic traffic studies have also confirmed the need to improve the flow of the east-west traffic through Central and Wan Chai, including the Long Term Road Study completed in 1968 and the First, Second and Third Comprehensive Transport Studies (CTS) completed in 1976, 1989 and 1999 respectively. A recent rerun of the CTS-3 transport model also confirmed the need for the CWB despite changes in land use planning assumptions and population projections.
the 9 January 2004 CFA ruling on compliance with the PHO, the compelling and
present need for the Trunk Road to meet the transport needs of the community within
a reasonable and definite planning time frame, and to meet the social and
economic needs of the community, was established under the CRIII project, and
is presented in “A Review of Central Reclamation Phase III by applying the
Court of Final Appeal’s “Overriding Public Need Test” April
the WDII project, the compelling and present need for the Trunk Road has also
been confirmed. Reference can be
made to the “Report on Cogent and Convincing Materials to Demonstrate
Compliance with the Overriding Public Need Test” (the CCM Report).
The CCM Report can be viewed at the website: http://www.devb.gov.hk/reclamation/en/basic/review_report/cogent_report/index.html.
2.4.6 Apart from providing land for key transport infrastructure and reprovisioned waterfront facilities, the Project can also create a coherent pattern of land use and provide for the development of an appropriate waterfront ‘edge’ to the existing urban area.
(i) Land formation for key transport infrastructure and facilities, including the Trunk Road (i.e. CWB) and the associated slip roads for connection to the Trunk Road and for through traffic from Central to Wan Chai and Causeway Bay. The land formed for the above transport infrastructure will provide opportunities for the development of an attractive waterfront promenade for the enjoyment of the public.
(ii) Reprovisioning / protection of the existing facilities and structures affected by the land formation works.
(iii) Extension, modification, reprovisioning or protection of existing storm water drainage outfalls, sewerage outfalls and watermains affected by the revised land use and land formation works.
(iv) Upgrading of hinterland storm water drainage system and sewerage system, which would be rendered insufficient by the land formation works.
(v) Provision of the ground level roads, flyovers, footbridges, necessary transport facilities and the associated utility services.
(vi) Construction of the new waterfront promenade, landscape works and the associated utility services.
(vii) The Trunk Road (i.e. CWB) within the study area and the associated slip roads for connection to the Trunk Road.
Project provides essential land for the construction of key transport
infrastructure including the Trunk Road and the NIL and SCL. The road and rail routes are required to
relieve congestion on the strategic east-west routes through Central, Wan Chai
Project also provides opportunity to create an attractive waterfront for the
enjoyment of the public. At
present, large parts of the Wan Chai,
benefits of the project have been discussed in paragraph
need to provide a strategic trunk road along the northern shore of
existing east-west corridor (Connaught Road Central –
2.4.13 A district traffic study has confirmed that a dual 3-lane Trunk Road (or Central-Wan Chai Bypass), together with intermediate slip roads, is required to divert traffic away from the existing east-west corridor and to provide adequate relief to the corridor and the local road network.
2.4.14 Traffic management and fiscal measures are already in place to maximise the capacity of the existing road network and suppress traffic demand. Further measures including ERP have also been considered. However, all these existing and proposed measures, alone, cannot resolve the traffic congestion problem along the east-west corridor. In other words, the Trunk Road is essential, and ERP can complement the Trunk Road but cannot replace it.
need for the Trunk Road has also been confirmed by the Expert Panel on
Sustainable Transport Planning and Central-Wan Chai Bypass, comprising leading
independent local and overseas transport planning experts. The Expert Panel supports the construction
of the CWB to improve the reliability of the road network and to enhance
multi-modal public transportation in the Connaught Road Central –
2.4.16 Land formed under the Project, in addition to providing for the construction of the Trunk Road, also provides for the construction of the NIL and the SCL. Should the Project not proceed, implementation of these rail routes will be severely constrained. This will have consequential adverse impacts on the planning and provision of public transport infrastructure.
2.4.17 Should the Trunk Road not be implemented the requirement for land formation will fall away and opportunities to improve the existing waterfront would be limited. The following scenarios are likely:
will be difficult to realise the Town Planning Board's objectives stipulated in
the Vision and Goals for
· it will also be difficult to achieve the harbour-planning principles established by the HEC, including, amongst others, sustainable development, proactive harbour enhancement, vibrant harbour, accessible harbour and public enjoyment.
· The existing odour nuisance at the CBTS would persist and no improvement of the situation would be expected. The Project will provide opportunities to remove the potential sources of odour nuisance within the CBTS so as to alleviate this existing environmental problem as well as to provide an acceptable environment for the future land uses within the project area.
the absence of project, similar air quality conditions along the northshore
areas of Wan Chai,
the absence of the project, the noise environment of the project area would be
increased due to the natural growth of traffic. In the presence of the project,
it would help lessen the traffic burden on
· No improvement of the existing landscape and visual conditions of the waterfront would be expected. With the implementation of the Project, there will be substantial to moderate positive landscape and visual impact along the new waterfront as the landscape and visual amenity are generally enhanced and strengthened.
2.5.1 Having established the need for the Trunk Road, any reasonable alternative to reclamation that may meet this overriding need must be determined. In other words, can an alternative alignment or form of construction for the Trunk Road be adopted that will obviate the need for reclamation? If there is a feasible “no reclamation” option, then it should be pursued. Only if the need for reclamation can be demonstrated to be necessary will scenarios involving minimum reclamation be contemplated.
detailed examination of Trunk Road needs and constraints, including an
exhaustive investigation into the need for reclamation for the Trunk Road
construction and of alternative schemes that might do away with reclamation or,
at least, minimise reclamation, has been carried out. A “Report on Trunk Road Alignments and
Harbour-front Enhancement, April
· avoid affecting existing services infrastructure such as electricity sub-stations and sewage treatment plants and the basement or piled foundations of existing developments along Wan Chai North, such as the HKCEC Extension, Grand Hyatt Hotel, Wan Chai Towers, Central Plaza, Renaissance Harbour View Hotel, Great Eagle Centre, Harbour Centre, China Resources Building and Sun Hung Kai Centre, etc.
routeings for the Trunk Road along offshore, inland and foreshore corridors
have been examined to determine practicable and feasible Trunk Road
alignments. Trunk Road alignments
are, however, constrained by existing development along the Wan Chai and
2.5.5 Offshore alignments are obstructed by the HKCEC Extension, will pose unacceptable risk to the Cross Harbour Tunnel when tunnelling beneath it, and cannot provide the necessary slip road connections. Due primarily to the physical conflict with the HKCEC Extension, Trunk Road offshore alignments are found to be not feasible.
2.5.6 Inland alignments are obstructed by existing development in Wan Chai North, including the HKCEC Phase I, Grand Hyatt Hotel, Great Eagle Centre and Sun Hung Kai Centre. Trunk Road inland alignments will also conflict with the proposed NIL and SCL rail infrastructure, and existing road and services infrastructure. Due to these physical conflicts, Trunk Road inland alignments are also found to be not feasible.
feasible Trunk Road routeing is along the foreshore of Wan Chai and
2.5.8 However, foreshore alignments do require reclamation for Trunk Road tunnel construction at the western end of WDII where the Trunk Road tunnel crosses over the MTR Tsuen Wan Line, and at the eastern end of WDII where the Trunk Road tunnel must rise to ground level for the connection with the elevated IEC, at least.
2.5.9 The following alternative Trunk Road ideas, including suggestions received from the public through the Envisioning Stage public engagement exercise, have been examined to determine if they would constitute a feasible “no reclamation” option, or result in an avoidance of reclamation:
2.5.10 All the alternative Trunk Road ideas that have been proposed to avoid reclamation are found either to be not feasible, or result in an even greater area of reclamation or affected area of the harbour than a foreshore alignment constructed as cut-and-cover tunnel and flyover.
the feasible Trunk Road routeing along the foreshore of Wan Chai and
2.5.13 Whilst there is broad support from the public for a tunnel option, especially where this can incorporate suggested harbour-front enhancement ideas while at the same time provide for the functional requirements of the Trunk Road, a flyover option is also technically feasible. This option has therefore also been considered, in particular as it represents a scheme requiring a lesser area of new land formation. At issue, though, is which option, tunnel or flyover, would comply with the PHO.
2.5.14 At-grade Trunk Road options are not acceptable as they would require extensive reclamation in the CBTS, thus not complying with the PHO, and the reclaimed land would be used mainly for roads, leaving little opportunity for harbour-front enhancement.
2.5.15 For the tunnel option for constructing the Trunk Road, three variations have been considered. These three variations are illustrated in Figures 2.1 to 2.3. Key features of the three variations are briefly described as follows:
2.5.16 The Trunk Road tunnel to be constructed under CRIII will be extended eastward to pass underneath the existing rock anchors of the CHT portal structure, and continues the tunnel to the east of the Causeway Bay Typhoon Shelter (CBTS) and connects to the northern side of the existing IEC.
Trunk Road tunnel to be constructed under CRIII will be extended eastward to
pass underneath the CHT at a position to the south of that in Variation 1 to
avoid the rock anchor zone, and continues the tunnel to the east of the CBTS
and connects directly into the IEC by reconstructing a section of the existing
IEC. For widening the harbour-front
promenade adjoining the CBTS and provision of a wide landscaped deck for
extending Victoria Park to the harbour-front, the
2.5.19 Under the flyover option, the tunnel to be constructed under CRIII will be extended eastward, and will rise up onto an elevated road structure at the waterfront opposite to the Wan Chai Sports Ground. Figure 2.4 illustrates this option.
PHO requires the Harbour to be protected and preserved as a special public
asset and a natural heritage of
2.5.21 Table 2.1 provides a comparison between the Trunk Road Tunnel Variations 1, 2 and 3, in broad terms, in respect of key indicators: area of reclamation, impacts to existing traffic, technical highway concerns and impacts to existing highway structures, impacts to existing development, planning and land use considerations, environmental concerns, time for construction and costs.
into and demolition of Victoria Park for the construction of the realigned
2.5.23 It should be noted that the areas of reclamation given in Table 4.1 are the areas of permanent reclamation, and include a notional allowance for reprovisioning requirements (for ferry pier, salt water pumping station, cooling water pumping stations, etc) associated with each of these tunnel variation options.
disruption due to reconstruction of
disruption due to reconstruction of
reconstruction of existing IEC at
of existing IEC from
of existing IEC from
2.5.24 It should also be noted that there will be a requirement for temporary works (including temporary reclamation) to facilitate cut-and-cover tunnel construction and for temporary traffic diversions. These temporary works will be required in the ex-PCWA basin and in the Causeway Bay Typhoon Shelter. In the Causeway Bay Typhoon Shelter, the extent of the temporary works, for all three tunnel variations, will be such that the existing moorings will need to be relocated outside the typhoon shelter during the construction period.
2.5.25 As can be seen, neither Tunnel Variation 2 nor 3 perform as well as the Trunk Road Tunnel Variation 1. The major drawbacks of Tunnel Variations 2 and 3 include additional reclamation for filling in of the corners of the Causeway Bay Typhoon Shelter, major traffic disruption, demolition of a large part of Victoria Park, demolition and then reconstruction of major highway structures, and air quality concerns at the tunnel portal area in North Point.
2.5.26 The reclamation issue is particularly important in respect of the PHO. The Trunk Road Tunnel Variation 1 requires a lesser extent of reclamation than that associated with the Tunnel Variations 2 and 3.
2.5.27 Table 2.2 provides a comparison between the tunnel and flyover options in broad terms, in respect of key indicators: affected area of the Harbour, impacts to existing traffic, technical highway concerns and impacts to existing highway structures, planning and land use considerations, environmental concerns, time of construction, and costs. Trunk Road Tunnel Variation 1 is used as the basis of tunnel option comparison. The key issue that is of concern in respect of the PHO is the area of the Harbour that will be affected by the tunnel and flyover options.
PHO requires the Harbour to be protected and preserved as a special public
asset and a natural heritage of the
2.5.29 Therefore, when examining Trunk Road options, and especially when examining the flyover option, the land formation by physical reclamation is taken into account together with the water areas of the Harbour affected by flyover structures in order to determine which option may serve best to protect and preserve the Harbour.
disruption due to reconstruction of
Localised reconstruction of existing IEC at
Reconstruction of existing IEC from
With the flyover running along the northern side of
Victoria Park, the landscaped deck over
Seaward portions of existing and planned
Significant air and noise impacts along flyover
Significant impacts in Wan Chai and (especially) in
2.5.32 The key issue of concern is which option would serve best to protect and preserve the Harbour. In addressing this concern, the area of the Harbour that is affected by the Trunk Road options should be taken into account, including not only land formed by reclamation but also the impingement of highway structures on the existing water areas and the restricted use of water areas due to the presence of the highway structures (ie the areas where the functionality of the Harbour is adversely affected). In addition, the visual aspects of the flyover option (viewed in terms of “preserving the Harbour”) should be considered. In these respects, the Trunk Road tunnel option is clearly the option that would serve best to protect and preserve the Harbour.
2.5.33 Comparing the tunnel variations, Tunnel Variation 1 is found to require the least extent of reclamation, would cause the least disruption to traffic during construction, has the least impacts to existing highway infrastructure and the least impacts to Victoria Park. It should be noted that, when considering Trunk Road variations having similar functional/traffic performance (ie in meeting the overriding need), the CFA ruling on the PHO requires that the one with the least amount of reclamation (in this case Tunnel Variation 1) should be selected. Therefore, of these tunnel variations, Trunk Road Tunnel Variation 1 is recommended, in compliance with the requirements of the PHO.
2.5.34 Although both capital and annual recurrent costs would be higher for the Tunnel Option when compared with the Flyover Option, the Tunnel Option is recommended, in compliance with the requirements of the PHO, primarily because the affected area of the Harbour would be smaller and it would cause less visual impact than the Flyover Option.
2.5.36 The first stage of the HER project, the Envisioning Stage, had as its purpose the engagement of the community at an early stage to solicit their visions on the need for and the form of Trunk Road as well as the types of harbour-front developments they aspire for at Wan Chai, Causeway Bay and the adjoining areas. Five public forums and two community design charrettes were convened during May to July 2005, and opinion surveys were carried out. These public engagement activities were well received by the public, in particular by the key stakeholders, as providing a platform for thorough exchange of views, rational discussions and consensus building.
2.5.37 The public’s views collected and findings of the Envisioning Stage are presented in a Public Engagement Report, March 2006. The report can be viewed on the HEC website at: http://www.harbourfront.org.hk/eng/content_page/doc/engagement_report/Main_Report.pdf.
addition, discussions with the Town Planning Board, Legislative Council
(LegCo), District Councils and relevant statutory and advisory bodies have also
been held, as part of an on-going and continuous process of public engagement
for seeking consensus on the project proposals. In particular, the Town Planning Board,
relevant District Councils,
2.5.41 The preferred Trunk Road Option, Trunk Road Tunnel Variation 1, provides for the necessary functional requirements of the Trunk Road, in meeting the overriding need for the Trunk Road, as well as resulting in the least affected area of the Harbour, in conformance with the PHO.
2.5.42 A detailed examination of Trunk Road needs and constraints, including an exhaustive investigation into the need for reclamation for the Trunk Road construction and of alternative schemes that might do away with reclamation or, at least, minimise reclamation, as well as review of harbour-front enhancement suggestions put forward by the public and the consolidation of these with the Trunk Road ideas, has been carried out. These have been described briefly above; more details on these assessments can be found in the “Report on Trunk Road Alignments and Harbour-front Enhancement”. After due consideration of these investigations, the HEC Sub-committee on WDII Review agreed at their meeting on 13 June 2006 to endorse Trunk Road Tunnel Variation 1 as the basis for proceeding to the next stage of the WDII Review, the preparation of the Concept Plan.
2.5.43 At the Envisioning Stage, alternative development options with different land uses for the harbour-front area have been proposed, such as proposals for lots of water sports and tourism activities along the water front, proposals for an informal waterfront along the study area as compared to a formal waterfront along Central waterfront, proposals for berthing facilities for visiting vessels with floating piers, openable footbridge link to the breakwater, urban beach at Causeway Bay Typhoon Shelter, extending Victoria Park to the waterfront, develop a lively harbour-front area at ex-PCWA, etc.
2.5.44 A Consolidation Forum was convened on 12 November 2005 to share with the public the comments and the different proposals received during the public enhancement activities held from May to July 2005 for the Envisioning Stage, and to involve the public in consolidating these views before proceeding with the preparation of the Concept Plan for the development and enhancement of the harbour-front area.
2.5.45 Details of the different development options proposed and the outcome of the Consolidation Forum at the Envisioning Stage are given in the Public Engagement Report, March 2006. The report can be viewed on the HEC website at: http://www.harbourfront.org.hk/eng/ content_page/doc/engagement_report/Main_Report.pdf. The outcomes of the Envisioning Stage on the development options and harbour-front enhancement then formed the basis of the preparation of the Concept Plan in the Realization Stage. The consolidated ideas for the preparation of Concept Plan are given below.
2.5.46 At the Envisioning Stage, there were many common land use concepts proposed for the harbour-front to enhance its vibrancy and attractiveness. These are mainly reflected in the following activity nodes:
2.5.47 These harbour-front suggestions have been consolidated with the Trunk Road Tunnel Variation 1 option, together with appropriate waterfront land use and landscape treatment. Harbour-front enhancement themes (arts, culture and heritage, leisure and recreation) are used to reinforce identity and provide variety and interest along the waterfront. The Concept Plan, as illustrated in Figure 2.5, that has been developed presents five “character precincts” as follows:
· a “heritage precinct” at the CBTS, preserving the existing typhoon shelter and taking advantage of the floating Tin Hau Temple, Noonday Gun, etc, and with a landscaped deck providing an extension of Victoria Park to the waterfront;
The Concept Plan, for the
development and enhancement of the harbour-front under the ambit of the WDII
Review, has been prepared for evaluation and consensus building by the public
in the Realization Stage. At a
2.5.49 The public’s views collected on the Concept Plan and findings of the Realization Stage are presented in a Public Engagement Report, April 2007. The report can be viewed on the HEC website at: http://www.harbourfront.org.hk/eng/content_page/engage.html?s=2.
2.5.50 Slip Road 8 will encroach into Victoria Park, affecting existing trees, recreational facilities and open spaces. Alternative alignments have been thoroughly examined with a view to minimising these impacts. A discussion paper that explains the considerations in examining the alignment of Slip Road 8 and associated at-grade road layout has been prepared and is attached in Appendix 2.4.
2.5.51 With reference to this discussion paper, amongst the different options of Slip Road 8 alignments, Option 1B, which has no encroachment into the North Pavilion Garden of Victoria Park, has been adopted. The final layout of Slip Road 8 and associated at-grade roads is given in Appendix 2.4.
the existing facilities and trees at the
2.5.53 The location of tunnel portal is directly related to the alignment of the Trunk Road, including both the vertical and horizontal alignments. The preferred Trunk Road Option, Trunk Road Tunnel Variation 1, provides for the necessary functional requirements of the Trunk Road, in meeting the overriding need for the Trunk Road, as well as resulting in the least affected area of the Harbour, determined as described above. The location of tunnel portal follows the alignment for Trunk Road Tunnel Variation 1.
2.5.54 Alternative tunnel locations have been included in the examination of alternative Trunk Road alignments and forms of construction, for example a portal location at Wan Chai North (flyover option) and further east along the North Point shoreline (deep bored tunnel option). Alternative tunnel portal locations, such as extending the tunnel and portal eastward, would result in more affected area of the Harbour as compared to the Trunk Road Tunnel Variation 1 and would not be in compliance with the PHO. These alternative tunnel portal locations are not recommended, nor are they permitted under the PHO.
2.5.55 Although the location of the tunnel portal is driven by the Trunk Road scheme with the minimum extent of reclamation and the least affected area of the Harbour, opportunity has been explored to enhance the east tunnel portal area. A landscaped deck has been proposed over the east tunnel portal area as shown in the Concept Plan (Figure 2.5) and the RODP (Figure 2.5a).
Alternative locations of
location of the
location of the
the Realization Stage of the HER public engagement activities, there were
public views and suggestions on the location of
locations of the vent shaft at the northern breakwater or the western
breakwater of the CBTS have also been explored. In view of the small contribution of the
exhaust from the vent shaft to the overall air quality, moving the vent shaft
at the eastern breakwater of CBTS to the northern breakwater or the western
breakwater of the CBTS would not result in any significant improvement of the
predicted air quality at ASRs in North Point. From the perspective of noise impact, no
difference is anticipated as the noise source is from the fixed plant of the
ventilation fans installed inside the
are two major infrastructures located on both sides of the western breakwater
namely the cross harbour gas main (about
the exhaust vent is located at the western breakwater, the air duct will go
alongside the mainline tunnel of the CWB in order to reduce the construction
difficulty and potential risk of being damaged. As the mainline tunnel will run
below the CHT at around
-30mPD, there will be substantial level difference of about
alignment of the CHT is right underneath the western end of the northern
breakwater, any extension of the air ventilation duct to and construction of
the exhaust vent at this location will entail reconstruction of the breakwater
and impose great risk of damaging the immersed tunnel tube of CHT. Furthermore, the alignment of the
proposed Shatin to Central Link (SCL) will run at about
There is no better practically feasible alternative location than the proposed location of the vent shaft at the eastern breakwater of CBTS in terms of a balance of engineering practicality, environmental benefits and visual compatibility to the surrounding environment.
The height of the vent shaft is
required to facilitate air dispersion and discharge, To achieve dispersion of the vitiated
air from the tunnel to the open air, the recommended minimum height measured
from the bottom of the louvres is
location of the
2.5.62 The size of reclamation, and the corresponding shoreline configuration, is determined based on the minimum extent of reclamation that is needed to meet the essential engineering requirements for the construction of the Trunk Road. It is the minimum reclamation required to meet the overriding need for the Trunk Road. A step by step approach is taken to ensure the reclamation is the minimum extent required. The first step is to confirm that there is an overriding and present need for the Trunk Road. The next step is to identify any “no-reclamation options”. If there is no reasonable alternative to reclamation, the third step is to ensure that the reclamation is restricted to only the minimum amount necessary to meet the overriding public need.
compelling and present need for the Trunk Road has been confirmed and reference
can be made to the CCM Report. The
need for the Trunk Road is explained in Section 2 of the CCM Report and also
mentioned in paragraphs
“no-reclamation” options are given in Section 3 of CCM Report. All possible alignments for the Trunk
Road, including suggestions from the public, have been examined, taking into
account land use and infrastructural constraints, with a view to determining if
there are any that do not require any reclamation for the Trunk Road
construction. It is found that the
feasible Trunk Road routeing is along the foreshore of Wan Chai and
“Report on Trunk Road Alignments and Harbour-front Enhancement, April
of the extent of reclamation, in respect of the engineering requirements for
the construction of the Trunk Road tunnel, reclamation and seawalls, are
presented in a “Minimum Reclamation Report”, a copy of which is appended at
Annex O of the CCM Report which can be viewed at the web site:
http://www.devb.gov.hk/reclamation/filemanager/en/content_19/annexO_e.pdf. Detailed examination of the
engineering requirements in respect of highway geometric design and
construction of the Trunk Road tunnel, reclamation and seawalls, and
reprovisioning requirements, has been carried out to accurately determine the
minimum extent of reclamation. In
total, an area of
2.5.67 With the size of reclamation being minimised to the minimum extent to meet the overriding need for the Trunk Road, the affected area of the harbour, the foreshore and seabed is minimised, and the corresponding environmental impacts, such as marine ecological and cultural heritage impacts, on the foreshore and seabed are also minimised. Details of the marine ecology and cultural heritage impact assessment for the proposed scheme shall refer to the respective sections in this WDII&CWB EIA Report.
presented in the “Minimum Reclamation Report”, as appended at Annex O of the
CCM Report, the shoreline (ie the seawall copeline) is set at the minimum
separation from the Trunk Road tunnel and it follows the curvature of the Trunk
Road tunnel edge. Smooth curves
have been adopted at indented areas rather than sharp corners along the
shoreline, and a curved splay in the seawall is incorporated at the corner with
2.6.1 Alternative construction methods have been considered in the CCM Report. Deep bored tunnel construction is given in Section 3.4; immersed tube tunnel construction method is discussed in Section 4.2; temporary reclamation for tunnel construction below seabed is discussed in Annex O of the CCM Report.
2.6.2 A deep bored tunnel option for the Trunk Road has been examined with a view to avoiding reclamation. The idea being that a tunnel constructed by tunnel boring machine (TBM) at sufficient depth below the surface would not require reclamation and can be constructed without disturbing existing facilities and infrastructure.
2.6.3 However, at the western end of WDII, at the connection with the Trunk Road tunnel constructed under CRIII and for the crossing over the MTR Tsuen Wan line, the deep tunnel option must start off as shallow cut-and-cover tunnel, in reclamation, similar to all other Trunk Road options. At the eastern end, as the tunnel rises towards the seabed and ground cover becomes insufficient for the TBM construction, the form of construction needs to change to cut-and-cover tunnel, with associated reclamation to facilitate this construction along the North Point shoreline. Therefore reclamation is still essential and the bored tunnel is not a “no reclamation” option.
2.6.4 The major issue associated with a deep tunnel option is that the longer length of the Trunk Road tunnel along the North Point shoreline, all the way to the connection with the IEC near the North Point ferry piers, results in extensive reclamation along this part of the shoreline.
2.6.5 The issue of reclamation, and whether it is unnecessarily extensive, is the key concern in this instance. Because the bored tunnel must rise from a deeper level under the Causeway Bay Typhoon Shelter than the alternative cut-and-cover tunnel option, the tunnel portal will need to be located further to the east along the North Point shoreline, where there is no existing formed land that can be put to good use to accommodate the ground level tunnel portal, as is the case for the connection immediately to the east of the CBTS. As a consequence, the deep bored tunnel option will require a greater area of reclamation along the North Point shoreline than the alternative cut-and-cover tunnel option. As the deep tunnel option will result in a greater area of reclamation than an alternative available tunnel option, and as in any event the deep tunnel option does not perform as well as the alternative cut-and-cover tunnel option, there is no justification or overriding need to pursue this deep tunnel option. Furthermore, the affected area of the harbour, the foreshore and seabed, will be greater, and the corresponding environmental impacts, such as marine ecological impacts, would be greater than the adopted Trunk Road Tunnel Variation 1.
2.6.6 Immersed tube tunnel form of construction may be used where the tunnel lies just below seabed; reclamation would not be required for this form of tunnel construction. However, this form of construction is not suitable where the tunnel level rises above seabed level, as the exposed tunnel section would then be at risk of damage from ship impact, anchors, etc, the tunnel structure would be more susceptible to degradation in the aggressive marine environment, and the protrusion of the tunnel structure above the seabed would restrict marine access to the shoreline. Also, even where the tunnel lies below seabed level, the soft seabed materials would need to be excavated so that the immersed tube units lie in a trench on a firm foundation. Along the Wan Chai shoreline, this would involve excavating a deep trench immediately adjacent to the existing seawalls, which would undermine these seawalls. Use of immersed tube is therefore considered not feasible in this instance, and the most practical and reasonable form of construction for the Trunk Road tunnel along the Wan Chai shoreline is cut-and-cover, constructed through reclaimed land.
2.6.7 Through the ex-PCWA basin and the CBTS, where the Trunk Road tunnel lies below seabed level, immersed tube or cut-and-cover tunnel construction may be considered. For both forms of construction, permanent reclamation is not required. In the case of cut-and-cover tunnel, temporary reclamation may be formed to facilitate the tunnel construction, but this can be removed on completion of construction so that the finished product, ie retention of the existing seabed condition, is the same for both methods. Factors to be considered in selecting an appropriate construction method include: whether the tunnel alignment runs wholly through seabed or partly in existing seabed and partly under existing seawalls and land formation, the latter making cut-and-cover construction more practically feasible (more efficient and cost effective construction with less disruption to existing shoreline facilities and infrastructure) than use of precast immersed tunnel sections that need to be placed in open trenches; the depth of the tunnel (where the tunnel lies at a significant depth below the seabed, for example near the Cross Harbour Tunnel crossing, at –30mPD, major deep and wide trenches will need to be excavated, making immersed tube construction more disruptive with greater impacts); or the tunnel length available for immersed tube construction (short lengths will not be cost effective for the precast fabrication of tunnel units). The form of tunnel construction is an important consideration in respect of avoiding conflict with the SCL, as Trunk Road cut-and-cover tunnel can be constructed across the future SCL alignment with much closer separation allowance. Because the Trunk Road tunnel is on diaphragm wall (piled) supports, it will not be structurally adversely affected by the construction of the SCL tunnels.
2.6.8 Where the Trunk Road tunnel rises up above the seabed to ground level, for the connection with the IEC at the eastern end of the CBTS, cut-and-cover tunnel in reclamation will again be the feasible form of construction.
2.6.9 In summary, cut-and-cover tunnel in reclamation is considered to be the practical and feasible form of construction for implementation of the Trunk Road at the west of the HKCEC, through the HKCEC water channel, along the Wan Chai shoreline and through the CBTS.
2.6.10 Cut-and-cover tunnel construction involves first installing the tunnel walls by using diaphragm walls (these are reinforced concrete wall panels constructed in existing ground from ground level down to the required depth, usually to the underlying rock layer) on both sides of the tunnel, then excavating the soil from between the diaphragm walls, constructing reinforced concrete top and bottom slabs between the diaphragm walls to form the tunnel box and, finally, backfilling over the tunnel. This form of construction is carried out in existing or formed land to provide the necessary construction access from the surface – should the tunnel alignment cross over seabed, reclamation will be required to first form the land through which the diaphragm walls need to be constructed.
Whereas cut-and-cover tunnel
construction is the practical and feasible form of construction for the overall
Trunk Road, there is localised section underneath the CHT portal approach ramp
where the Trunk Road tunnel will be generally in rock. As mentioned in paragraphs
2.6.12 Alternative construction method like the drill-and-blast method which is normally used for tunnels through rocky hills and mountains, not for tunnels below seabed with mixed soil conditions, is considered not applicable in this case.
2.6.13 The Trunk Road must not impose any loads on, or cause any movement of, the existing MTR Tsuen Wan Line immersed tube tunnel. Tunnelling under the MTR tunnel at sufficient depth to avoid disturbance to the existing ground and movement of the MTR tunnel would result in exceedance of permissible tunnel gradients from the connection to the existing road network at the Central Interchange. A piled Trunk Road tunnel structure spanning across the MTR tunnel will be constructed to meet statutory limitations on allowable surcharge, lateral pressure and movement.
2.6.14 The Trunk Road tunnel beneath the ex-PCWA basin and the CBTS will be constructed by cut-and-cover method, for which reclamation is required (as explained above). Through these areas, though, the Trunk Road tunnel structure lies at sufficient depth below the seabed that consideration can be given to removing the reclamation after the tunnel has been constructed. The criteria for deciding where the reclamation can be removed are: that the top tunnel should be deep enough to allow for adequate structural protection in the absence of the protective reclamation, and where the tunnel passes through anchorage areas, an additional seabed layer for ships’s anchor embedment; and that the removal of reclamation should not have the effect of creating new embayments, in order to avoid water quality impacts.
2.6.15 Note that these temporary reclamation areas are not considered as areas affecting the harbour, insofar as they are short term (for the duration of the construction period) and solely for the purpose of achieving the end product (ie in order to ultimately achieve minimum reclamation). The temporary works will not cause permanent damage to the harbour.
2.6.16 A number of existing waterfront facilities (ferry piers, drainage culverts, cooling water intakes, sewage outfall, etc.) will be affected by the WDII reclamation. Although these facilities will be reprovisioned under the Project, they should be kept functional and operational during reclamation until the reprovisioned facilities are constructed and available for use. There is therefore a requirement for reclamation to be carried out in stages, with careful planning of construction sequence for both the reclamation and reprovisioning works.
2.6.17 The resultant reclamation staging creates a number of relatively small and confined areas of land formation. Containment of fill within each of these areas by seawalls is proposed, with the seawalls constructed first and filling being carried out behind the seawalls. This method will allow the land area formed in each stage to be maximised and also has significant benefits in terms of water quality; by containing all filling behind seawalls, the release of suspended sediments during the filling operations will not impact the open water areas of the harbour.
2.6.18 Seawall construction will, in general, comprise wave energy absorbing caisson seawall units, where exposed to harbour waves, constructed on dredged foundations for stability reasons. These caisson seawall units will be in the form of precast caisson units. In lieu of casting the precast units at the works site, off-site (Mainland) precast yard will be used for casting of these precast units and transportation to the seawall construction site by sea will be the common alternative adopted for precast works.
2.6.19 Dredging of marine mud is required for the foundations of the seawalls, culverts, at-grade roads, and associated with the construction of the CWB tunnel. The minimum extent of dredging required for foundations of the seawalls, roads and drainage culverts, and for practical engineering and construction reasons due mainly to the narrow configuration of the reclamation, effectively results in a fully dredged approach over the length of the site. Figure 2.6 indicates the proposed extent of dredging for the WDII project.
2.6.20 The use of marine sand fill is proposed, with fill placed behind the enclosing seawalls of each reclamation stage. The use of marine sand fill will enable the formed land to comply with required engineering and settlement performance criteria, with the fill placed within a very tight programme in order to meet critical project completion dates. Transportation of marine sand fill will mainly by barges to achieve the filling rate to meet the construction programme.
2.6.21 While marine sand is proposed to be used generally for filling, detailed investigations have been conducted to explore the possibility of using public fill and surplus rock fill from appropriate sources that may be identified during the detailed implementation stages of the project, where engineering, programme and implementation constraints permit. The investigations indicate that it is possible to use public fill from Penny’s Bay Reclamation Stage 2 (PBR2) in the upper formation layers, above +2.5 mPD. For the temporary reclamation where settlement is not a major concern, public fill from PBR2 for the full depth of reclamation is proposed, to maximise the use of public fill materials. Transportation of public fill from PBR2 to the works site will mainly by barges as both the supply and demand locations are at their respective shorelines. Delivery of reused construction and demolition materials within the site and/or surplus materials to the public fill reception facilities will be by barges for large quantities and by truck for local and small quantities.
2.6.22 The reprovisioned Wan Chai East ferry pier will be a piled structure, similar to the existing pier structure. Some concrete members or panels of the ferry pier structure may be in the form of precast units. Similar to the precast caisson units, besides casting the precast units at the works site, off-site precast yard in Mainland for casting of these precast units and transportation to the seawall construction site by sea will be the common alternative adopted for precast works.
The work site for the project
will be located within the construction works area and the duration of works
are given in the construction programme (Appendix
2.5). Alternatively, precast or
prefabrication work may be carried out at off-site area in Mainland
2.7.1 Operational activities, on completion of the Project, would comprise essentially traffic movements on the new roads and public use of the waterfront. The RHKYC will continue to operate as at present. Other than the new waterfront leisure uses, there are no major changes of land uses which will result in new operations not already taking place along this shoreline.
2.8.2 As noted in Section 2.6 above, construction needs to be carried out in stages in order to meet the services and utilities reprovisioning requirements and construction sequencing constraints. A staged construction programme, with works in each area being carried out sequentially has been developed to meet the objectives of the Project. The staging of the reclamation works, with respect to the above issues and constraints, is shown indicatively in Figures 2.7 to 2.19. A brief description of the proposed works, with reference to the staging requirements, is given in the following paragraphs.
2.8.3 The construction works can be considered in terms of three mains works areas being, from east to west, the North Point and Causeway Bay Reclamation, the Wan Chai Reclamation and the HKCEC Reclamation.
2.8.4 The reclamation at North Point will be in a two stages. The central area of reclamation will commence first to provide land for temporary reprovisioning of the FEHD Depot while the new Depot is under construction. The reclamation on either side will follow subsequently but the construction of the Trunk Road tunnel structure, which is partly on existing land, will commence after the temporary relocation of the existing FEHD Depot. The land formation at the eastern end of this reclamation area will be handed over for the construction of the tunnel approach ramp and connecting to the existing IEC.
2.8.5 The temporary reclamation in the typhoon shelter is divided into four stages to avoid creating an embayed water area with a pond of stagnant water between the temporary reclamation and the existing seawall during construction, and to allow the reuse of filling and surcharge materials between reclamation stages.
2.8.6 Works for the North Point and Causeway Bay Reclamation will commence in early 2009. The permanent land formation at North Point will be completed by late 2010 for handing over of works area for construction of tunnel approach ramps. The Trunk Road tunnel structure will be completed by early 2015 for tunnel installations and fitting out. Operational completion of the Trunk Road will be in 2016.
2.8.7 Four stages have been proposed for Wan Chai Reclamation, in addition to the temporary reclamation of the ex-PCWA basin. The first stage is constructed between the existing Wan Chai East sewage outfall and the existing seawater intakes for WSD and Sun Hung Kai. This land needs to be formed in advance to allow the diversions of the sewage outfall and seawater intake pipelines.
The following stages, on either
side of this advance reclamation area, are constructed subsequent to the
diversion of the sewage outfall and the seawater intakes. The construction sequencing of these
stages also makes provision for the drainage outfalls from
2.8.9 Works in this area also commence in early 2009, with land formation being completed by mid 2013 and the Trunk Road tunnel structure completed by mid 2014 for tunnel installations and fitting out. Operational completion of the Trunk Road will be in 2016.
2.8.10 Reclamation in this area takes place after diversion of the existing cooling water intakes to the intake chambers already provided on the north side of the HKCEC. Reclamation on either side of the MTR Tsuen Wan line will follow the bored pile wall construction on either side for the Trunk Road crossing over the MTR line. Reclamation of the HKCEC water channel takes place before adjacent reclamation to either the east or west of the HKCEC Extension so as to avoid embayment of this confined water area.
2.8.11 Reclamation in this area would commence in early 2009 and would be completed by mid 2012. The Trunk Road tunnel works would be completed by early 2014 for tunnel installations and fitting out. Operational completion of the Trunk Road will be in 2016.
(i) Civil Engineering and Development Department's CRIII project, comprising reclamation along the Central waterfront for transport infrastructure needs (including CWB and NIL) and basic land use requirements. A section of CWB tunnel will also be constructed under CRIII project. Construction will take place from February 2003 to September 2012.
(ii) Trade Development Council’s Atrium Link Extension project, comprising a link bridge spanning across the water channel between the Hong Kong Convention and Exhibition Centre (HKCEC) Phase I and HKCEC Extension. Construction will take place from May 2006 to March 2009. No cumulative dust impact from the Atrium Link Extension Project is expected.
 Electrostatic Precipitation
The polluted tunnel air extracted from the eastern
tunnel portal will be filtered by electrostatic precipitator installed at the
 Zero Portal Emission Design
For a typical unidirectional tunnel, tunnel traffic will create piston effect which will draw outside air from entry portal and drives the induced air to exit portal. Tunnel ventilation system will induce additional outside air to satisfy minimum air quality standard inside the tunnel in the event that piston effect alone is not able to induce adequate outside air to ventilate the tunnel. The tunnel air both induced by tunnel traffic and brought by tunnel ventilation system will escape through exit portal if no extraction system is provided upstream of the exit portal. If a powerful extraction system is provided upstream of the exit portal to extract all the polluted air, it is possible to have a system with “zero portal emission”. The amount of air flow into the tunnel induced by traffic piston effect can be predicted by using the SES (subway environmental simulation) programme under all modes of traffic conditions. The portal extraction system will be designed with over capacity (about 20%) to cover the worst traffic scenario to ensure that no polluted tunnel air will escape through the exit portal. The extraction system will operate at reduced capacity to cover other scenarios when the emission rate of traffic induced air to exit portal is less than the maximum.
The current ventilation system proposed for the CWB project consists of three extraction fans for the eastern tunnel portal. Two fans will be adequate to extract all polluted air from the upstream tunnel section of the exit portal. The third fan would be used as standby in case one fan is under maintenance or out of order. Airflow direction sensor will be installed at the exit portal to monitor the airflow direction of the tunnel. This sensor will be used to control the operation of tunnel portal extraction system to ensure that the target of “zero portal emission” will be met. For reference, similar “zero portal emission” design has been adopted in Sydney M5 East Tunnel.