Contents

 

 1            Introduction  1

1.1             Background  1

1.2             EIA Study Brief 1

1.3             Need for the Project 2

2              Consideration of Revised Scheme Alignments  3

2.1             Overview of Alignment Corridor 3

2.2             Public Consultation  3

2.3             Convenience for the Population to be Served  4

2.4             Base Scheme Alignment in the EIA Study Brief 4

2.5             Development of the Revised Scheme Alignment 4

2.6             Comparison of Base Scheme and Revised Scheme Alignments  5

2.7             Selection of the Alignment 11

3              Project Description and Construction Methodology  12

3.1             General Alignment 12

3.2             Summary of Design  12

3.3             Implementation Programme  13

3.4             Proposed Construction Methodology  13

3.4.1         Alignment Sections  13

3.4.2         Stations and Entrances  15

3.4.3         Ventilation Building  16

3.4.4         Tunnel Portals  16

3.4.5         Off-Site Temporary Works Areas  16

4              Summary of Key Findings in EIA Study  18

4.1             General 18

4.2             Cultural Heritage Impact 18

4.3             Ecological Impact 18

4.4             Landscape and Visual Impact Assessment 19

4.5             Air Quality Impact 22

4.6             Airborne Noise Impact 22

4.6.1         Construction Noise  22

4.6.2         Operational Noise  22

4.7             Groundborne Noise  22

4.8             Water Quality  23

4.9             Waste Management 23

4.10          Land Contamination  23

4.11          Hazard to Life  24

4.12          Environmental Monitoring and Auditing Requirements  24

5              Overall Conclusion  25

 

Tables

 

Table 2.1              Key benefits of the interchanging stations

 

Table 2.2              Summary of design changes and environmental implications of revised scheme alignment

 

Table 3.1              Summary of design of SCL Tai Wai to Hung Hom section

 

Table 3.2              Tentative construction methods for different alignment sections

 

Table 3.3              Tentative Construction Methods for Stations and Entrances

           

Table 3.4              Tentative construction method for portals

 

Table 3.5              Tentative uses for off-site temporary works areas

 

Figures

 

Figure 1.1            General Alignment of SCL

 

Figure 1.2            Locations of Off-site Works Areas

 

Figure 2.1            Comparison of Base Scheme and Revised Scheme Alignment

 

1            Introduction

1.1            Background

The Shatin to Central Link (SCL) is one of the railway projects recommended for implementation in Railway Development Strategy 2000.  It is an integral component of the expanded rail network, which will be required to support the economic, social and population growth of the HKSAR in the coming years.  In particular, it will support the urban renewal of the existing Kowloon City District, planned Kai Tak Development (KTD) and further developments in North East New Territories (including Ma On Shan) by providing direct and efficient rail service between Shatin and the Central Business District of the Hong Kong Island via KTD.

The SCL is also one of the ten large-scale infrastructure projects announced by the Chief Executive in his 2007-2008 Policy Address. According to updated information, SCL is targeted to commence construction by 2012. For the purposes of the Environmental Impact Assessment (EIA), five EIA Studies have been conducted to cover different sections of the SCL.  They include:

·          SCL – Tai Wai to Hung Hom Section [SCL (TAW-HUH)] (hereinafter referred to as “the Project”, being considered in this EIA) – the extension of Ma On Shan Line from Tai Wai Station via Hing Keng, Diamond Hill, Kai Tak, To Kwa Wan, Ma Tau Wai and Ho Man Tin to Hung Hom, and link up with the existing West Rail Line, along with a proposed stabling sidings option in Diamond Hill (DHS)1;

·          SCL – Mong Kok East to Hung Hom Section [SCL (MKK-HUH)] – the realignment work for the existing East Rail Line tracks from the tunnel portal near Oi Man Estate (Portal 1A) to the proposed North Ventilation Building (NOV) in Hung Hom;

·          SCL – Hung Hom to Admiralty Section [SCL (HUH-ADM)] – the section from NOV, Plant Rooms and Emergency Access in Hung Hom across the harbour to the Causeway Bay Typhoon Shelter (CBTS), Exhibition Station (EXH) and then to ADM;

·          SCL Protection works at Causeway Bay Typhoon Shelter – the section of approximately 160m long of the SCL tunnel protection works at the crossing over Central-Wan Chai Bypass (CWB) tunnels, which would be constructed under the CWB project; and

·          SCL – Stabling Sidings at Hung Hom Freight Yard [SCL (HHS)] – another stabling sidings option for SCL (TAW-HUH) proposed at the former freight yard in Hung Hom[1].


The proposed tentative alignment of SCL (TAW-HUH) is shown in Figure 1.1 and the tentative locations of off-site works areas (e.g. office, general storage), off-site works sites (e.g. barging facilities, magazine sites etc) are shown in Figure 1.2. More detailed description of the proposed Project is given in Sections 2 and 3. Ove Arup & Partners Hong Kong Ltd (Arup) was commissioned by MTR Corporation Limited (the Project Proponent) as the EIA Consultant for the SCL (TAW-HUH). The SCL (MKK-HUH), SCL (HUH-ADM), Protection Works at Causeway Bay Typhoon Shelter and SCL (HHS) are separate Designated Projects and their EIA Studies would be conducted separately.

1.2            EIA Study Brief

The Project is a single project comprising the following elements which are considered as designated projects as per Schedule 2, Part I, Categories A2, A4, A7, A8 and K10 of the Environmental Impact Assessment Ordinance (EIAO), as summarised below:

·          A.2: A railway and its associated stations.

·          A.4: A railway siding, depot, maintenance workshop, marshalling yard or goods yard.

·          A.7: A road or railway tunnel more than 800 m in length between portals.

·          A.8: A road or railway bridge more than 100 m in length between abutments.

·          K.10: An explosive depot or explosives manufacturing plant in a stand-alone, purpose built building.

The stabling sidings options at Diamond Hill for SCL(TAW-HUH) is covered in this EIA study.  This stabling siding option is a Designated Project under Item A.4. of Schedule 2 of EIAO.

The explosive storage magazine described in this EIA will be constructed under the Kwun Tong Line Extension (EIA 184/2010) and would be share used between Kwun Tong Line Extension and the Project.  An explosives depot in a stand-alone, purpose built building is a designated project (under Item K.10, Part 1 of Schedule 2 of the EIAO) (Referred to in this report as an explosives storage magazine).  The future decommissioning of the explosives magazine is a designated project (under Item 11, Part II – Decommissioning Projects of Schedule 2 of the EIAO).  As the date of the decommissioning is uncertain at this stage, it is not considered under this EIA Study.  However, an Environmental Permit will be required prior to commencement of decommissioning work.  

An application (No. ESB-191/2008) for an Environmental Impact Assessment (EIA) Study Brief under Section 5(1)(a) of the EIAO was submitted by the Project Proponent on 18 June 2008 with a project profile (No. PP-356/2008) (the Project Profile).  Pursuant to Section 5(7)(a) of the EIAO, the Director of Environmental Protection issued an EIA Study Brief (ref: EIA Study Brief No: ESB- 191/2008 dated 14 July 2008) to provide the scope and requirements of the EIA Study for SCL (TAW-HUH). 

It should be noted that the EIA Study Brief has included a total of 7 stations, including Hin Keng Station (HIK), Diamond Hill Station (DIH), Kai Tak Station (KAT), To Kwa Wan Station (TKW), Ma Tau Wai Station (MTW), Ho Man Tin Station (HOM) and Hung Hom Station (HUH). During the design process after the issuance of EIA study Brief, however, engineering and programme considerations have supported the construction and operation of HOM to be implemented, under the Kwun Tong Line Extension (KTE). Similarly, HUH would also be implemented under SCL (MKK-HUH). Whilst HOM and HUH will be assessed under separate EIAs, the cumulative impacts due to the construction and operation of these 2 stations have also been considered in this EIA to fulfil the requirement in the EIA Study Brief.

1.3            Need for the Project

The entire Shatin to Central Link is to form a strategic rail corridor from Shatin to Central which will bring about various benefits to the community, including:

·          Redistribution of railway passenger flows to relieve the existing railway lines in urban Kowloon and on Hong Kong Island;

·          Providing public transport service for Kai Tak Development;

·          Relieving road-based public transport in the existing developed areas, and alleviation of the traffic congestion and environmental nuisance on existing road networks, including the demand on the Hung Hom Cross Harbour Tunnel; and

·          Stimulation of the redevelopment of To Kwa Wan and Kowloon City areas.

2            Consideration of Revised Scheme Alignments

The SCL is a strategic railway line that runs through multiple districts in Hong Kong.  It will strengthen the current railway networks by connecting several railway lines through a number of interchange stations. It will save travelling time and provide the community with faster and more convenient railway services.  As discussed in Section 1, this EIA is prepared for the SCL (TAW-HUH), while the EIAs for SCL (MKK-HUH), SCL (HUH-ADM), Protection Works at Causeway Bay Typhoon Shelter and SCL (HHS) are covered by other EIA Studies. 

SCL (TAW-HUH) is an approximately 11km long extension of the MOL and connects the WRL at Hung Hom.  Most of the sections would be in the form of tunnel (i.e. underground) except for a section at Hin Keng, and another section at Hung Hom (see Figure 2.1), at which the alignment has to raise to connect with the existing MOL and WRL.

Other than linking the areas in Tai Wai and Hung Hom, the SCL (TAW-HUH) also aims to support the urban renewal of the existing Kowloon City District and planned Kai Tak Development.  The alignment corridor therefore, after leaving the existing MOL Tai Wai Station, heads towards East Kowloon via Hin Keng and Chuk Yuen.  The first station after passing Lion Rock is DIH where passengers can conveniently interchange to the existing Kwun Tong Line (KTL).  Covered under this Project would be the train stabling sidings option occupying the former Tai Hom Village site to the south of DIH.

Passengers can also continue their journey to reach the future Kai Tak Development Area to the south of Diamond Hill where lot of different developments including public housing, private housing, sports venue etc have been planned.  This KAT is an important and sustainable transportation infrastructure element that the future population in Kai Tak Development could enjoy.

In order to serve the population in Kowloon City, Ma Tau Wai, To Kwa Wan etc, the alignment (after passing Kai Tak area) has been planned to pass through all these areas and with stations provided.  It will then reach HOM where passengers can interchange with the proposed KTE which is an extension of the existing KTL at Yau Ma Tei Station to Whampoa Garden.

Finally, passengers heading towards Hung Hom and Hong Kong Island can interchange at HUH.  The remaining passengers can enjoy the seamless integration with the West Rail Line and access various areas in Tsim Sha Tsui East, West Kowloon and other areas along West Rail Line to Tuen Mun. As discussed in Section 1.2, both HOM and HUH would be implemented under another Designated Projects.

This EIA has considered the option of having the train stabling sidings located at Diamond Hill (i.e. DHS option). Recent study has revealed another possible option at Former Hung Hom Freight Yard (i.e. HHS option). The environmental assessment for HHS option including cumulative impacts has been separately addressed in the EIA for SCL (HHS).

2.2            Public Consultation

When selecting the preferred option, major factors that were considered included not only the engineering factors and environmental factors, but also views from the public received during the public consultation exercise.

As one of the SCL Project Objectives, an extensive series of meetings/consultations with public has been conducted during the preliminary design stage of the Project, with an objective to formulate a final scheme which meets the needs of the local community and is fully supported by the general public.

After the Executive Council approved the further planning and preliminary design of SCL by the MTR in March 2008, the Government and the MTR subsequently visited the District Councils and consulted local communities on the project.  Extensive public consultation, including roving exhibitions and public forums, was conducted in collaboration with various District Councils and the local community to further collect views from the public on the new links.

The passengers for SCL (TAW–HUH) would have the choices to interchange at a number of stations to suit their needs. A summary of the key benefits of the interchange stations is given below.

Table 2.1:  Key benefits of the interchanging stations

Interchange Stations

Key Benefits

TAW

·          Passengers from East West Corridor can interchange to the North South Corridor to access north east New Territories and Hung Hom

DIH

·          Passengers on SCL (TAW-HUH) can interchange to KTL to access East Kowloon and Central Kowloon

HOM [1]

 

·          Passengers on SCL (TAW-HUH) can interchange to KTE to access Whampoa and Central Kowloon

HUH [2]

 

·          Passengers on SCL (TAW-HUH) can interchange to SCL (MKK-HUH) and SCL (HUH-ADM) or carry on to connect to the West Rail Line

Note:

[1] As part of another Designated Project: Kwun Tong Line Extension (AEIAR-154/2010)

[2] As part of other Designated Project: SCL (MKK-HUH)

Environmental factors have been important considerations during the alignment selection process. The development of this base scheme alignment in the EIA Study Brief has in fact avoided a number of critical environmental issues including the following.

·          Avoidance of at-grade construction works and permanent structures within the Lion Rock Country Park which is important for ecological conservation and landscape and visual resources;

·          Minimise above-ground works area to minimise disturbance in urban areas in which a lot of local residents / communities are living in close proximity to the construction works areas and the stations;

·          Avoid natural streams and secondary woodland in Tai Wai; and

·          Avoid alignment inside the consultation zone of the gas depot of China Gas Co. at the junction of Ma Tau Kok Road and To Kwa Wan Road.

The Project Proponent has appointed a Preliminary Design Consultant (PDC) responsible for the preliminary design of the SCL (TAW-HUH).  One of the key objectives of preliminary design is to develop further on the base scheme alignment and identify any alternative options that would benefit the local communities better, including the public’s concern on the need for HIK and shifting the alignment closer to Kowloon City District to tie in with the change in future population centre, as a result of no reclamation in Kai Tak area where the population will therefore be reduced.

In addition to the PDC, the Project Proponent has also appointed an EIA Consultant to advise on the environmental implications of different alignment and design options.  Both the PDC and the EIA Consultant have been working to strike an optimal balance between different requirements of engineering, practicability, environmental, land constraints, etc.

The environmental implications arising from revising the base scheme alignment have been examined, and the environmental implications for the base scheme and revised scheme alignments have been compared and presented in Table 2.2. Figure 2.1 shows the base scheme and revised scheme alignments.

Table 2.2: Summary of design changes and environmental implications of revised scheme alignment

Base Scheme Alignment

Proposed Changes of

Revised Scheme Alignment

Environmental Benefits

Environmental Disbenefits

Remarks

Location

Design

Alignment Sections

Tai Wai Depot

At-grade

·   No change

·   N/A

·   N/A

-

Tai Wai Depot to HIK

Embankment

·   No change

·   N/A

·   N/A

-

HIK to Hin Keng Portal

Viaduct + Embankment + Tunnel

 

·   No change

·   N/A

·   N/A

-

Hin Keng Portal to DIH

Tunnel

(drill-&-blast within Lion Rock Country Park to Chuk Yuen, bored tunnel from Chuk Yuen to Po Kong Village Road, and Cut-&-Cover from Po Kong Village Road to DIH)

·   Underground alignment between Chuk Yuen and Po Kong Village Road slightly adjusted. 

·   No significant change in tunnel length.

·   NIL

·   NIL

·   Most of the section would be within Lion Rock Country Park and there would be no at-grade temporary construction works within the country park area.  Together with the fact that the construction method would remain the same, it is anticipated that there are no additional environmental impacts as compared to the base scheme alignment.

·   Amount of spoil to be excavated would be similar.

DIH to KAT

Tunnel

(bored tunnel + cut-&-cover)

·   No change

·   N/A

·   N/A

-

KAT to TKW

Tunnel

 (bored tunnel)

 

·   Alignment will be shifted to the north.

·   TKW relocated.

·   Change of tunnel construction from bored tunnel to cut-&-cover and mined tunnel.

·   Tunnels between KAT and TKW will be constructed in railway reserves inside future residential development sites in the Kai Tak Development. Provisions have been made for future development foundations and basement to be constructed in close proximity to these tunnels. Cut and cover form of tunnels will provide more flexibility for future basement construction under this special arrangement".

·   No significant change in tunnel length.

·   NIL

·   The revised scheme alignment would however have interface with the Former Kowloon City Pier. All necessary engineering measures would be implemented to protect the pier during construction. (See Section 4)

 

·   The alignment would be closer to the existing receivers along Ma Tau Chung Road but further away from the receivers along To Kwa Wan Road.  Both alignments have similar density of NSRs, ASRs and VSRs along both sides. Hence, the associated environmental impacts on noise, air quality and visual would be similar.

·   Amount of spoil to be excavated would be similar.

TKW to MTW

Tunnel

(bored tunnel)

·   Alignment will run along Ma Tau Chung Road / Ma Tau Wai Road instead of To Kwa Wan Road.

·   Construction method remains the same.

·   No significant change in tunnel length.

·   Alignment would avoid the PHI consultation zone of the gas depot of China Gas Co. The separation distance between the alignment and the PHI consultation zone is about 160m.

·   The revised scheme alignment would however be closer to some built heritage (e.g. the Trinity Church building and the Sung Wong Toi Rock.  The assessment has concluded that the impacts on these heritage items would be insignificant. (See Section 4).

·   The alignment would be closer to the existing receivers along Ma Tau Chung Road/ Ma Tau Wai Road but further away from the receivers along To Kwa Wan Road.  Both alignments have similar density of NSRs, ASRs and VSRs along both sides. Hence, the associated environmental impacts on noise, air quality and visual would be similar.

·   Amount of spoil to be excavated would be similar.

MTW to HOM

Tunnel

(drill-&-blast + cut-&-cover/ bored tunnel)

 

·   Alignment will run along Ma Tau Wai Road.

·   MTW  relocated.

·   Tunnel construction method changes to drill-&-blast + bored tunnel.

·   No significant change in tunnel length.

·   NIL

·   NIL

·   The alignment would be closer to the existing receivers along Ma Tau Wai Road but away from the receivers along To Kwa Wan Road.  Both alignments have similar density of NSRs, ASRs and VSRs along both sides.  Hence, the associated environmental impacts on noise, air quality and visual would be similar.

·   Amount of spoil to be excavated would be similar.

HOM to HUH

Tunnel (cut-&-cover/ bored tunnel) + at-grade section

·   Tunnel construction method changes to cut-&- cover method.

·   NIL

·   Slightly higher noise and air quality impacts with cut-&-cover method.

·   Amount of spoil to be excavated would be similar.

HUH to WRL Tunnel

Tunnel + at-grade section

·   No change

·   N/A

·   N/A

-

Stations

HIK

Elevated station

·   No change

·   N/A

·   N/A

-

DIH

Underground station

·   No change

·   N/A

·   N/A

-

Diamond Hill Stabling Sidings (DHS)

Semi-underground

·   No change

·   N/A

·   N/A

-

KAT

Underground station

·   No change

·   N/A

·   N/A

-

TKW

Underground station

·   Station relocated

·   NIL

·   The station will be located in the vicinity of an area where assemblage of Song Dynasty pottery was discovered. Mitigation measures would be required to minimise the impacts (See Section 4)

·   The station would be closer to the existing receivers along Ma Tau Chung Road but further away from the receivers along To Kwa Wan Road.  Both would have similar density of NSRs, ASRs and VSRs in the vicinity.  Hence, the associated environmental impacts on noise, air quality and visual would be very similar.

·   Amount of spoil to be excavated would be similar.

MTW

Underground station

·   Station relocated

·   NIL

·   NIL

·   The station would be closer to the existing receivers along at Ma Tau Wai Road but further away from the receivers along To Kwa Wan Road.  Both would have similar density of NSRs, ASRs and VSRs in the vicinity.  Hence, the associated environmental impacts on noise, air quality and visual would be very similar.

·   Amount of spoil to be excavated would be similar.

HOM*

Underground station

·   No change

·   N/A

·   N/A

-

HUH*

Semi-underground station

·   No change

·   N/A

·   N/A

-

Ventilation Buildings/ Shafts

HIK

Above-grade structure

·   No change

·   N/A

·   N/A

-

Ma Chai Hang

Above-grade structure

 

·   Shifted from near Chuk Yuen North estate to Ma Chai Hang Recreation Ground

·   Roof level of ventilation building would be kept as low as possible and close to surrounding road levels to reduce visual impact. 

·   NIL

·   Similar environmental setting (e.g. nature and number of sensitive receivers) and hence significant change in environmental implications not anticipated.

TKW

Above-grade structure

·   Station relocated.

·   Physical size remains similar.

·   NIL

·   NIL

·   Similar environmental setting (e.g. nature and number of sensitive receivers) and hence significant change in environmental implications not anticipated.

MTW

Above-grade structure

·   Station relocated.

·   Physical size remains similar.

·   NIL

·   NIL

·   Similar environmental setting (e.g. nature and number of sensitive receivers) and hence significant change in environmental implications not anticipated.

Emergency Access (EA)/ Emergency Escape Access(EEA)/ Emergency Egress Point (EEP)

Ma Chai Hang

Above-grade structure

·   Safety requirement

·   The building is required to give firemen access to tunnel and to give safe egress to passengers from the tunnel in the event of an emergency.

·   Integrated with Ma Chai Hang Ventilation Building, and visual impacts would be reduced

·   NIL

-

Wong Tai Sin

 

·   Safety requirement

·   The building is required to give firemen access to tunnel and to give safe egress to passengers from the tunnel in the event of an emergency.

·   NIL

·   Above-grade structure.

·   Slight construction dust, noise and visual impacts

-

Tam Kung Road

 

·   Safety requirement

·   The building is required to give firemen access to tunnel and to give safe egress to passengers from the tunnel in the event of an emergency.

·   NIL

·   Above-grade structure.

·   Slight construction dust, noise and visual impacts

-

Note:

* According to the latest arrangement, the HOM and HUH will be separately implemented by other Designated Projects under KTE and SCL (MKK-HUH) respectively. However, the cumulative impacts due to these 2 stations would be addressed in this EIA as well to fulfil the requirement in the EIA Study Brief.

2.7            Selection of the Alignment

Two alignment options have been considered.  The main difference is the portion from KAT to MTW.  The base scheme alignment runs along To Kwa Wan Road after KAT before joining HOM. In order to serve the population better, the revised scheme alignment has been designed to run along Ma Tau Chung Road/ Ma Tau Wai Road.  The TKW is also relocated to the western side of Kai Tak Development area adjacent to Olympic Garden, whereas MTW is relocated to Ma Tau Wai Road adjacent to Ma Tau Wai Road/ To Kwa Wan Road Garden. Both TKW and MTW will be moved closer to existing and future population centres and will serve a larger population.

Both the base scheme and revised scheme alignments are similar in total length, construction methods, amount of spoil generated.  Also, the number of stations and ventilation buildings will be identical in the two schemes. The number of environmental sensitive receivers from noise, air quality, visual, ecology etc would be similar. The revised scheme alignment would be closer to heritage items including the Former Kowloon City Pier, the landing steps of the 1924 seawall and the area where assemblage of Song Dynasty pottery were discovered. However, proper engineering solutions have been proposed.

The revised scheme alignment would also avoid the consultation zone of the gas depot of China Gas Co at the junction of Ma Tau Kok Road and To Kwa Wan Road (see Figure 2.1).  Therefore, no hazard-to-life for the construction workers would be expected.

Hence, the revised scheme alignment would generally be better in terms of environmental performance with implementation of appropriate mitigation measures. In addition, it would offer more benefits to the general public using the proposed railway. The revised scheme alignment is therefore selected and adopted as the basis for this EIA study.

3            Project Description and Construction Methodology

The SCL (TAW-HUH) is an approximately 11km long extension of the Ma On Shan Line (MOL) from Tai Wai through new stations, including Hin Keng Station (HIK), Diamond Hill Station (DIH), Kai Tak Station (KAT), To Kwa Wan Station (TKW), Ma Tau Wai Station (MTW), Ho Man Tin Station (HOM) and connects the West Rail Line at Hung Hom Station (HUH).  Most of the sections would be underground except for a section at Hin Keng, and another section at Hung Hom, where the alignments need to be raised and linked with the Ma On Shan Line and the West Rail Line respectively to form a strategic east-west rail corridor (see Section 2.3). The underground sections of the alignment would be constructed by various construction methods including drill-and-blast, cut-&-cover, bored tunnelling, and mined method.  Open cut/ cut-&-cover method will be employed for the tunnel portals at Hin Keng and Hung Hom North Fan area, and most of the stations and ventilation building structures, etc. 

DIH will become an interchange station with the existing KTL.  The SCL (TAW-HUH) will interchange with the KTE and the SCL (MKK-HUH) at HOM and HUH respectively. The HOM and HUH are part of other Designated Projects to be separately implemented.

A new train stabling sidings is required to provide stabling facilities and to allow effective train launching to meet the service requirements of SCL(TAW-HUH).  Covered under this Project would be the train stabling sidings option located at Diamond Hill CDA site (i.e. former Tai Hom Village).

The SCL (TAW-HUH) will also form an important part of the proposed Kai Tak Development, providing mass transit service not only to the proposed new commercial and residential developments in the area, but also the Multi-Purpose Stadium Complex and other leisure facilities planned at Kai Tak.

The proposed tentative alignment is shown in Figure 1.1 and the tentative locations of off-site works areas (e.g. office, general storage, barging facilities, magazine sites etc.) are shown in Figure 1.2.

A summary of the general design of SCL (TAW-HUH) is given below:

Table 3.1: Summary of design of SCL Tai Wai to Hung Hom section

Type

Location

Design

Alignment sections

Tai Wai Depot

At-grade

Tai Wai Depot to HIK

Embankment

HIK to HIK Portal

Viaduct + Embankment + Tunnel

HIK Portal

Embankment

HIK Portal to DIH

Tunnel

DIH to KAT

Tunnel

KAT to TKW

Tunnel

TKW to MTW

Tunnel

MTW to HOM

Tunnel

HOM to HUH Portal

Tunnel

HUH Portal

From Tunnel to At-grade

HUH Portal to WRL Tunnel

At-grade section

Stations

HIK

Elevated station

DIH

Underground station

Diamond Hill Stabling Sidings (DHS)

Semi-underground

KAT

Underground station

TKW

Underground station

MTW

Underground station

HOM [1]

Underground station (by other Designated Project)

HUH [1]

Semi-underground station  (by other Designated Project)

Ventilation Building

Ma Chai Hang

At-grade structure

Emergency Access/Emergency Escape Access (EA/EEA)

Wong Tai Sin

At-grade structure

 

Ma Chai Hang

Integrated with Ma Chai Hang Ventilation Building (MCV)

Emergency Egress Point (EEP)

Tam Kung Road

At-grade structure

Notes:

[1]        The HOM would be implemented under the KTE.  The HUH would be implemented under the SCL (MKK-HUH). Their cumulative impacts have been addressed in different sections of this EIA to fulfil the requirements of the EIA study Brief.

According to the latest programme, the construction works for SCL (TAW-HUH) would commence in 2012.  All major civil contracts would be completed by 2016.  The remaining works including station fit-out, track layout etc would be completed by 2018.

3.4            Proposed Construction Methodology

3.4.1        Alignment Sections

The proposed Project would be constructed mostly in tunnel except for a viaduct and an embankment section in Tai Wai and an at-grade section in Hung Hom.  A tentative concept for the preliminary construction methodology is given below for initial information and would be subject to changes during the on-going design process. A summary of tentative construction methods is shown in Table 3.2 below.

Table 3.2: Tentative construction methods for different alignment sections

Section

Form

Tentative Construction Method

Tai Wai to HIK and Hin Keng Portal      

At grade + Embankment + Viaduct + Cut-&-cover

 

Typical viaduct construction:

·      The substructure could be in a form of column pier with pier head.

·      The box girder viaduct would be constructed by cast in-situ method supported on traditional falsework.

Embankment/ At grade

·      The semi-to fully underground portion of tunnel box facing Hin Keng Estate before entering Hin Keng Portal would be constructed by typical cut-&-cover method.

Portal

·      Hin Keng Portal will be constructed by mined tunnel method to avoid ecological impact on Tei Lung Hau stream

Hin Keng Portal to Ma Chai Hang               

Tunnel

Drill-&-blast tunnelling:

·            A small section of mined ground tunneling would be constructed at Hin Keng Portal.  The construction would avoid the Tei Lung Hau freshwater stream and the neighbouring secondary woodland.

·            The long tunnel between Hin Keng Portal and Ma Chai Hang (underneath the Lion Rock Country Park) will mainly be constructed by drill-and-blast method. 

·            A ventilation building constructed by cut & cover method, will be located at the Ma Chai Hang Recreation Ground.

(NB There is no at-grade construction activities within the Lion Rock Country Park.  All the construction works within the Lion Rock Country Park would be underground.)

Ma Chai Hang to DIH

Tunnel

Bored tunnelling:

·            A TBM launching chamber is planned at Ma Chai Hang Recreation Ground. The retrieval chamber is located at the north end of DIH.

DIH to KAT

Tunnel

Combination of cut-&-cover and bored tunnelling:

·            The mainline tunnels between DIH and Kai Tak north would be constructed by bored tunnelling. The TBM launching shaft would be located at Kai Tak north and the TBM retrieval chamber would be located at DIH. 

·            The stabling entry tracks from stabling sidings to Kai Tak Development area would be constructed by cut-&-cover method and bored tunnel.  TBM retrieval shaft would be located at south of Choi Hung Road.

DHS

Semi-underground

 

·            The DHS and the associated tunnels from the stabling siding to the entry tracks near south of Choi Hung Road will be constructed by cut-&-cover method.

KAT to TKW

Tunnel

Cut-&-Cover tunnelling:

·            The tunnels would pass under the Former Kowloon City Pier and 1924 Seawalls.

·            For the tunnel section between Former Kowloon City Pier and KAT, trench excavation within braced cofferdam has been proposed to preserve buried seawall steps of the 1924 seawall north of the tunnel alignment that would otherwise be disturbed by open cut excavation. The 1924 seawall will be exposed in the trench excavation nearer Kai Tak Station. For the tunnel section directly under the Former Kowloon City Pier buffer zone (for a section of about 40m),  mined tunneling with a vertical separation of 1.8m – 2.2m between the bottom of the piers and the top of the tunnel structure would be included.

TKW to MTW

Tunnel

Bored tunnelling:

·            The tunnels between the south end of TKW and the north end of MTW are located within the dense urban environment along Ma Tau Chung Road/Ma Tau Wai Road.

·            TBM launching shaft is planned at the southern end of TKW and the retrieval shaft at the Shansi Street Carpark. A rock crusher will also be operating within the tunnel section.

·            There would not be any at-grade construction activities within this section except for the ground treatment works as necessary.

MTW to HOM

Tunnel

Combination of cut-&-cover/ bored tunnelling and drill-&-blast tunnelling:

·            A circular construction works shaft is proposed at the existing open space car park at Shansi Street for the retrieval of TBM machine from MTW and provide access to tunnel works towards HOM.

·            Bored tunnelling method will be employed for the section between MTW and Shansi Street Carpark. 

·            The 500m section of tunnels between works shaft at Shansi Street Carpark and HOM would be constructed as twin single-track tunnels, using the drill-&-blast method. 

HOM to HUH

Tunnel + at-grade

Cut-&-cover tunnelling:

·            The tunnel section crossing Chatham Road North and near to Winslow Street would be constructed using cut-&-cover method. Passing through the HUH portal adjacent to Sai Sing Funeral Parlour, it will become at-grade section with concrete open trough.

HUH to WRL Tunnel

At-grade

Open Cut

·            The section between HUH section and the WRL stub tunnel would be constructed using open cut method.

3.4.2        Stations and Entrances

Except for HIK and HUH, all the other stations would be underground.  Their tentative construction methodologies and associated entrances are summarized below.

Table 3.3:  Tentative Construction Methods for Stations and Entrances

Stations and Entrances

Tentative Construction Methodologies

HIK

Elevated Station:

·         The station foundation would employ bored piling and the superstructure will be constructed by in-situ concreting. 

Other stations including:

·         DIH

·         DHS

·         KAT

·         TKW

·         MTW

Underground Stations:

·         For stations other than KAT, the station foundation would employ either bored piles or D-walls and the underground structure will be constructed by in-situ concreting.

·         KAT will be constructed by open-cut method.

                            Note: The construction for HOM and HUH will be implemented under other Designated Projects

As all proposed stations will situate in soft ground (except HOM which would be implemented by another designated project), cut-&-cover method will be deployed for all stations excepted for KAT and TKW, which would be constructed by open-cut and cut-&-cover method separately.

3.4.3        Ventilation Building

There is only one separate ventilation building in Ma Chai Hang for SCL (TAW-HUH).  The ventilation shaft in Tai Wai has been integrated with the HIK to minimise landscape and visual impacts. Other stations would have ventilation shafts as necessary. 

The ventilation building is above-grade and would be constructed by typical building construction methodologies.  Key stages of the construction for ventilation buildings include the following:

·          Foundation construction (either by bored piling or diaphragm wall);

·          Superstructures (typically by in-situ concreting); and

·          Architectural landscaping and builder’s works.

3.4.4        Tunnel Portals

There are 2 portals for the proposed Project, one at Hin Keng and one at Hung Hom at the STT car park at Winslow Street. The Winslow Street Garden will be employed as works site for the construction of Hung Hom portal, which will be re-provisioned in the same location in the operational phase. Their construction methodologies are summarized below:

Table 3.4: Tentative construction method for portals

Portals

Tentative Construction Methodologies

Hin Keng

·         Mined tunnel/ cut-& cover

Hung Hom

·         cut & cover

3.4.5        Off-Site Temporary Works Areas 

In addition to the temporary works sites in the vicinity of the tunnel and station structures, there are some off-site temporary works areas to facilitate the construction process and they are summarized below:

Table 3.5: Tentative uses for off-site temporary works areas

Off-Site Works Areas

Proposed Uses

Kai Tak Runway

·      Barging activities (sediment removal is required)

·      Approximately 39,500 m2

Freight Pier at Hung Hom [1]

·      Barging activities (sediment removal not required)

·      Approximately 43,000 m2

TKO Area 137

·      Magazine site

·      Approximately 11,100 m2

Ma On Shan (Heng On and Tai Shui Hang)

·      Contractor site office

·      Workshop

·      Storage of materials and equipment

·      Approximately 7,430 m2

Shek Mun (in Shatin)

·      Contractor site office

·      Workshop

·      Storage of construction materials and equipments

·      Approximately 31,100m2

Pak Tin

·      Temporary storage area

·      Approimately 2,100m2

Note:

 [1] Shared use with KTE and SCL (MKK-HUH).

 

It should be noted that, other than the works area for the sediment removal works for the barging facility at Kai Tak Runway, all the off-site works areas have been previously employed as temporary car parks or works areas under other infrastructure projects.  It is not necessary to increase the footprints of these off-site temporary works areas for the SCL (TAW-HUH).

4            Summary of Key Findings in EIA Study

The EIA Study has been conducted in accordance to the EIA Study Brief No. ESB – 198/2008 and the TM-EIAO. Cumulative impacts with other concurrent projects have been taken into account in the assessment. This Executive Summary highlights the key identified impacts, potential sensitive receivers and proposed mitigation measures. The main findings of the EIA Study are summarised below.

Built heritage survey and archaeological survey have been conducted within the study area of the SCL (TAW-HUH). Some archaeological sites, 16 currently graded historical buildings, 1 proposed graded historical buildings, and a number of other buildings with historical merit but without grading have been identified within the Study Area.

The archaeological survey at former Tai Hom Village has revealed the Tang/ Song Dynasty remains to be sparse and redeposited and hence of lesser archaeological significance. Assemblage of Tang/Song archaeological finds within urban setting is however considered rare in Hong Kong. A survey-cum-excavation is therefore recommended to be conducted at the former Tai Hom Village to recover any archaeological remains.

A similar survey-cum excavation would also be conducted for the excavation area, where the open cut construction of TKW and the associated tunnel overlap with the Sacred Hill (North) archaeological Site. Separate archaeological survey conducted in 2010 for the Sacred Hill (North) Study Area has revealed archaeological potential of this site.

The alignment has been designed to totally avoid Lung Tsun Stone Bridge within Kai Tak area. For the Former Kowloon City Pier adjoining the south of Lung Tsun Stone Bridge, a vertical separation can be maintained to avoid impacts. A horizontal buffer zone would be maintained for the Lung Tsun Stone Bridge and Former Kowloon City Pier. 

The built heritage within 300m of the alignment has also been studied. Three historical structures (i.e. former RAF hangar, Stone House (No. 4 Tai Koon Yuen) and Old Pillbox) are located within the former Tai Hom Village, which would be used for the DIH Stabling Sidings. The physical conditions of the Former Royal Air Force Hanger and the Stone House No. 4 are not satisfactory for total preservation.  The condition of Pillbox is better and may be feasible for total preservation.  A conservation plan would be separately submitted to agree on the most appropriate approach to preserve these 3 historical buildings. Depending on the recommendations in the conservation plan, part of the hangar together with a model would be displayed and the old pill box would be reinstated within the CDA Site.

Other recorded built heritage items have been surveyed and the impacts to the majority during SCL (TAW-HUH) construction and operation will be minimal.

The ecological baseline has been updated by reviewing available information and the results of ecological surveys of at least 5 months covering both dry and wet seasons. The ecological survey covers 500m of the proposed alignment for sections above ground and for the temporary works areas. 

According to the ecological baseline, terrestrial habitats within the Study Areas are largely developed areas with high disturbance and low ecological value.  Works at the Hin Keng portal have been modified and designed to avoid any direct or indirect impacts to the high ecological value Tei Lung Hau stream. Whilst the alignment will run through the Lion Rock Country Park, the alignment would run within the rock layer. Furthermore, there would not be any permanent land intake or temporary works areas within the country park boundary.

Direct and indirect ecological impacts arising from the Project during construction have been identified and evaluated. Most impacts are considered to be of low significance. In areas where species of conservation interest have been recorded, i.e. Rhesus Macaque (Macaca mulatta) in plantation close to refuse collection point at Hin Keng, Little Ringed Plover (Charadrius dubius) at wasteground in KAT site, Kai Tak Runway Barging Facility and TKO Area 137, Cattle Egret (Bubulcus idis) at Kai Tak Runway Baring Facility and the Aquilaria sinensis at secondary woodland to the southwest of Tei Lung Hau, potential impacts have been identified and mitigation measures have been recommended. Detailed vegetation survey in the Hin Keng Portal area would be conducted to identify any individuals of Aquilaria sinensis which are protected species. Where necessary, these Aquilaria sinensis would be considered for transplantation and a transplantation plan will be prepared. Precautionary checks for roosting Fruit Bat in all Chinese Fan Palms in DIH and DHS; and/or nesting bird species of conservation interest in DIH, DHS and works area in Kai Tak Barging Point, prior to any tree-felling and/or vegetation removal have been recommended.

Due to navigation requirement, dredging would be required for the barging facility in Kai Tak Runway. Marine habitats within the Study Area of the dredging works area for this facility are generally of low of ecological value due to their highly artificial and disturbed nature. Species diversity and abundance in these habitats were low and no rare or restricted species was recorded. Indirect impact on existing coral colonies and other macrofauna of the benthic environment during the dredging activities are considered to be minor.

Indirect impacts arising from the Project would be temporary and considered as negligible in nature. Overall, no significant and unacceptable ecological impacts to terrestrial, freshwater or marine resources were anticipated.

All the landscape resources and landscape character areas in the vicinity of the Project and all the visually sensitive receivers within the visual envelopes during the construction and operational phases have been identified. 

The key sources of impact during construction stage are from activities associated with the construction of the aboveground structures within the works area of the Project.  The key sources of impact during operational phase are confined to the aboveground structures including HIK with viaduct and tunnel box, noise barriers at Hin Keng, MCV, EA/EEA at Wong Tai Sin, DHS, Tam Kung Road EEP, Hung Hom portal, station entrances and ventilation shafts. Potential impacts have been considered during the development of the project design to avoid direct impact on important landscape resources, such as Old and Valuable Trees, natural stream and wooded hillside.  The physical extent of the works area has also been minimized as far as possible to minimize impacts on the identified landscape resources and visual sensitive receivers.

About 3,030  trees will be affected by the Project, of which about 900 trees are located on slopes and 386 trees will require transplantation. Tree removal application and compensatory tree planting proposal will be prepared and submitted to seek approval from relevant authorities in accordance with ETWBTC 3/2006 requirements, prior to construction of the Project.

Other landscape and visual mitigation measures have been identified for both the construction and operation phases to mitigate unavoidable adverse impacts. Roof greening on HIK, tunnel box from HIK towards Hin Keng Portal, MCV, EA/EEA at Wong Tai Sin has been recommended to minimize the visual impact and enhance the visual quality to the VSRs.

After implementation of these mitigation measures, there would still be some adverse landscape impacts during the construction phase, mainly due to the impacts on existing trees along the project alignment and impacts on public open space for the construction of SCL (TAW – HUH) stations and ventilation building. During the operational phase, after the mitigation measures (e.g. tree transplanting, compensatory tree planting, aesthetic landscape and architectural treatment, vertical greening and roof greening) have been implemented and tree planting has matured over 10 years, it is considered that the residual landscape impact would be slight to insubstantial, with the exception of impacts on Hin Tin Playground, Ma Chai Hang Playground and Diamond Hill CDA Site.

Hin Tin Playground and Ma Chai Hang Playground which are considered to be of moderate adverse impact significance due to the permanent loss of about 3,100m2 and 2,065m2 of public open space of landscape amenity area for the construction of HIK and MCV respectively.  The loss of open space at Hin Tin Playground would fully be compensated by the provision of the open space at Shek Mun (approx 3,100m2).  Since Wong Tai Sin is a developed community, it is not feasible to reprovision the same area for the loss of about 2,065m2 in Ma Chai Hang Playground within the nearby vicinity. However, having considered the requirements of the Hong Kong Planning Standards and Guidelines in the context of the overall planning of open space provision in the area, the loss of 2065m2 of open space within Ma Chai Hang will have relatively insignificant impact. 

The Diamond Hill CDA Site will be subject to adverse impact of moderate significance with the permanent loss of about half of the vegetated area within this landscape resource (LR) and disturbance of a large number of trees. For the railway facilities within the Diamond Hill CDA Site, the open areas around the above ground structures of the railway associated facilities will be planted with amenity planting and approximately 90 trees to mitigate the loss of landscape resources.  In addition, green roofs are proposed on the DIH entrance/ plant structures near Lung Cheung Road to minimize the potential adverse landscape and visual impacts.

Except for the area that would be allocated to railway associated facilities, the remaining part of the CDA site is being actively planned for future usage. The Diamond Hill CDA Site development is anticipated to be implemented following commissioning of the railway. It is anticipated that the future developer would implement typical landscaping measures including tree planting to beautify the deck in an appropriate manner to alleviate the potential adverse landscape and visual impacts. The future owners/ allocatees would maintain the green open areas, although the landscape plan could be further refined during the planning of the future development. It is considered that the impact during the operational phase in the long term after land allocation to be moderate and acceptable with mitigation.

In the unlikely event the CDA site is not allocated within 12 months following the commissioning of the railway facilities, it is proposed that interim greening measures, such as hydroseeding or planting over a thin soil base or importation of temporary pots and removable planters are implemented on the roof of DHS as landscape and visual mitigation measures. The maintenance of the interim greening measures will be undertaken by MTR Corporation for the first 12-month establishment period.  In the case that the site is still not allocated after the establishment period, MTR Corporation would liaise with relevant government departments to agree on the subsequent maintenance agent of the interim greening measures.  MTR Corporation would be responsible for the maintenance of the interim greening measures before any agreement is made. It is considered that the impact during the transition period, after completion of DHS and before land allocation, to be moderate and acceptable with such mitigation measures.

In terms of visual impacts and in consideration of duration of impacts which is considered to be temporary in nature during construction phase, and mitigation measures will be implemented to protect the VSRs, the overall visual impacts are acceptable, with moderate and insubstantial visual impacts. However, some VSRs are subject to short-term substantial residual impacts, which is unavoidable due to their close proximity where there are direct views to the work sites. They are Hin Keng Estate (South) (HIK/VSR 1.10), Lung Poon Court (DIH&KAT/VSR 1.1), Galaxia (DIH&KAT /VSR 1.3), Rhythm Garden-North (DIH&KAT/VSR 1.2), Future residential development along Prince Edward Road East (DIH&KAT/VSR 1.7), Residential development at Housing Site 1A&1B (DIH&KAT/VSR 1.16), Rhythm Garden-South (DIH&KAT/VSR 1.17), Tsui Chuk Garden (MCH/VSR 1.2), Wang King House/ Wang Yuen House (MCH/VSR 1.3), Fu Yuen House/ Kwai Yuen House/ Wing Yuen House (MCH/VSR 1.4) and Chung Hong House/ Chung On House (MCH/VSR 1.5), and they will be affected by the site formation works and removal of trees along the project alignment. In the operational phase, after the mitigation measures have been implemented and effect of tree planting has been fully realized over 10 years, it is considered that the residual visual impacts would be slight to insubstantial with the exception for some VSRs at close proximity and/or have view from higher height level on the site such as:

·          Residents in Hin Keng Estate (South) (HIK/VSR1.10), due to its close proximity to the proposed viaduct tunnel box and the at-grade box section at Hing Keng, will be subject to adverse visual impact.  With the incorporation of the proposed mitigation measure of landscape treatment including roof greening together with green treatment of climber plants along walls of the built structures, the bulk of the viaduct and the at-grade box section would be soften visually. Therefore, the residual visual impact is predicted to be moderate in Day 1 and Year 10.

·          Residents in Lung Poon Court (DIH&KAT/VSR 1.1), Rhythm Garden-North (DIH&KAT/VSR 1.2), Galaxia (DIH&KAT/VSR 1.3) and workers at Hong Kong Sheng Kung Hui Nursing Home (DIH&KAT/VSR 2.3) at close proximity with a high vantage point to the large topside of the proposed DHS will be subject to adverse visual impact. With the incorporation of the proposed mitigation measures including interim greening measures such as hydroseeding or planting over a thin soil base or importation of temporary pots and removable planters for visual greenery on the topside of DHS, aesthetic landscape and architectural treatment to the station entrances, plant rooms, ventilation shaft and planting along boundary of these built structures, the bulk of the building would be softened visually. The Diamond Hill CDA site is planned for development, which is anticipated to have been allocated upon commissioning of the railway. In the event the site is not allocated within 1 year upon commissioning, it is proposed that interim greening measures as mentioned above would be implemented on the roof of DHS to mitigate the landscape and visual mitigation impacts. This mitigation will provide visual relief to the surrounding VSRs at high level, and will improve views on the otherwise unmitigated bare concrete roof of the DHS.  It is anticipated that the future developer would implement typical landscaping measures to beautify the deck in an appropriate manner when the land is allocated.  Although the land allocation process is still yet to be completed, planting will be provided within some of the areas around the railway facilities as interim mitigation measures.  The planting area will be maintained by the Project Proponent prior to handing over to the relevant government departments.  The future owners/ allocatees would maintain the greenery in these areas although the landscape plan could be further refined during the planning of the future development. With the implementation of the above mitigation measure and upon the completion of the landscaping measures implemented by the future developer, the level of visual impacts to the above VSRs is considered to be moderate in Day 1 and Year 10.

Overall, it is considered that the landscape and visual impacts in the construction and operation phases are acceptable with mitigation measures.

4.5            Air Quality Impact

Potential dust impact would be generated from the soil excavation activities, backfilling, site erosion, storage of spoil on site, transportation of soil, as well as blasting activities during the construction of SCL (TAW – HUH).

Quantitative fugitive dust assessments have been conducted, taking into account the cumulative impact caused by nearby concurrent project. Effective dust control following the requirements given in the Air Pollution Control (Construction Dust) Regulation and in accordance with the EM&A programme during construction are recommended.  Assessment results suggested that watering at Shatin and Kowloon once per 1.5 hour and once per hour respectively would be required to control the fugitive dust impact to acceptable levels.

4.6.1        Construction Noise

Potential construction noise impacts would be caused by various construction activities including excavation, backfilling and construction of superstructure etc.

Construction noise assessment has concluded that the unmitigated construction noise impacts would be high at some NSRs.  Suitable noise mitigation measures have therefore been identified which could reduce the noise impacts at most of the NSRs. The use of bored tunnelling in Wong Tai Sin, Diamond Hill and Ma Tau Wai has largely reduced the potential airborne construction noise impacts on the receivers along the bored tunnel areas. Careful selection of construction equipment and working methods including the use of electrically driven and quiet plant are adopted, where practicable. Other measures including good site practice, the use of site hoarding, installation of movable barriers and sequential operation of construction plant have been recommended. The predicted noise levels at most of the NSRs would comply with the corresponding noise criteria, except for a few NSRs near the works areas including HIK, DIH, TKW, MTW and Chatham Road North. All practicable mitigation measures are exhausted and the impacts are minimised.

The Project Proponent will facilitate communications with concerned parties on the residual impacts exceeding the construction noise criterion during construction and review to consider other initiatives, such as Indirect Technical Remedies (ITR), if required.  (N.B.: the use of ITR as a mitigation measure is neither a requirement under Annex 13 of the EIAO-TM nor the EIA Study Brief.)

4.6.2        Operational Noise

Operational noise impacts associated with railways and fixed noise sources have also been investigated.  The SCL (TAW – HUH) would be underground except for the viaduct, embankment and the at-grade sections at Hin Keng, and at-grade sections at Tai Wai and Hung Hom. Airborne noise associated with the operation of railway would be minimized by the underground design. Some mitigation measures in the form of noise cover and barriers have been recommended for the section between Tai Wai Depot and HIK.

Fixed noise sources during the operational phase include ventilation/ plant buildings, ventilation shafts and E&M plant in the station. Operational noise impacts can be effectively mitigated by implementing noise control treatment (e.g. acoustic silencers and louvers) at source during the design stage to control the noise levels to be within the stipulated noise criterion.

4.7            Groundborne Noise

Potential construction groundborne construction noise impacts may arise from tunnel boring activities. Groundborne noise assessment has been conducted for the development along the bored tunnel areas in Wong Tai Sin, Diamond Hill and Ma Tau Wai.  Predicted results suggested that construction groundborne noise levels will be within the statutory requirements and mitigation measures are not required.

Operational groundborne noise impacts have been assessed at representative sensitive receivers along the alignment. The predicted groundborne noise would be within the statutory requirements and mitigation measures are not required.

4.8            Water Quality

Potential water pollution sources have been identified as construction runoff, sewage from site workforce, drainage diversion and groundwater contamination. Mitigation measures including covering excavated materials and providing sedimentation tanks on-site etc are recommended to mitigate any potential water quality impacts.

To minimise the potential impact due to suspended solids, deployment of silt curtains around the closed grab dredgers is recommended for the dredging works at Kai Tak Runway barging facility to minimize water quality impact in the Victoria Harbour.

According to the quantitative assessment for dredging activities, the cumulative water quality impact due to concurrent dredging activities from the Cruise Terminal construction would be well within the acceptable level.

The operational water quality impact for track run-off and tunnel seepage would have no adverse water quality impact provided that mitigation measures are incorporated in the design.

4.9            Waste Management

The quantity and timing for the generation of waste during the construction phase have been estimated.

Measures, including the opportunity for on-site sorting, reusing excavated fill materials etc, have been maximised in the construction methodology to minimise the surplus materials to be disposed off-site via barging facilities. The annual disposal quantities for C&D materials and their disposal methods have also been assessed.  Surplus rock and spoil materials could be accepted by other projects. Testing results for chemical and biological tests indicate that about 29,200m3 of marine based sediment would require Type III Special Treatment/ Disposal.

For Type 3 special disposal treatment, sealing of contaminant with geosynthetic containment before dropping into designated mud pit which has also been proposed for Type 3 disposal in the EIA Study under Wan Chai Development Phase II and Central-Wan Chai Bypass (WDII) (EIA 141/2007) would be a possible arrangement.

General refuse, industrial waste and chemical waste generated during the operational phase have been assessed.  Recommendations such as regular collection of general and industrial wastes by reputable waste collector, proper labelling and storage of chemical wastes have been made to ensure proper treatment and disposal of these wastes.

Historical information on site geological information, ground condition, and aerial photos has been reviewed. Contamination Assessment Plan (CAP), Contamination Assessment Report (CAR) and Remediation Action Plan (RAP) have been prepared to set out the requirements for a contamination evaluation of the SCL (TAW – HUH) alignment and works areas and endorsed by EPD in December 2010. With the subsequent change in the status of the land application for the location and size of works sites and works areas, a supplementary CAP and a supplementary CAR has been prepared. A total of 29 sampling locations have been established for soil and groundwater analysis. 

Testing results indicated that one soil sample at former Tai Hom Village required remediation.  A total volume of 39m3 is recommended to be disposed of at the landfill. Testing results of groundwater sample indicate that none of the groundwater samples exceed the Risk-Based Remediation Goals for groundwater for industrial purpose.

Due to the site access problem, re-sampling at NT South Animal Centre would only be conducted after the site is resumed and handed over to the Project Proponent.  Following the completion of SI  at this site and laboratory testing works of samples collected, a second supplementary CAR and RAP (if contamination is confirmed) shall be prepared and submitted to EPD for agreement.

Remediation Report(s) shall also be prepared and submitted to EPD for endorsement prior to the commencement of any construction works within identified contaminated area.

In view of foreseen ground condition and the impracticability in using other techniques, drill and blasting for rock excavation is required for some sections along the alignment. To enable a timely delivery of explosives to site and in order to meet the proposed construction work programme, a temporary Explosives Storage Magazine (Magazine) is required. A Quantitative Risk Assessment (QRA) for the storage, transport and use of explosives has been carried out as per the EIA Study Brief No. ESB-191/2008 (EIA Study Brief). A robust site selection process has been undertaken for the proposed temporary magazine and Tseung Kwan O (TKO) Area 137 has been identified as the only practicable site. The criterion of the EIAO-TM for Individual Risk has been met. The assessment results show that the societal risk lies within the As Low As Reasonably Practicable (ALARP) region when compared to the criteria stipulated in Annex 4 of the EIAO-TM. An ALARP assessment has been carried out by identifying all practicable mitigation measures and assessing the cost effectiveness of each measure in terms of the risk reduction achieved and the cost of implementing the measures. As part of the ALARP assessment, every potential temporary magazine site candidate has been reviewed and the TKO Area 137 has been confirmed as the only practicable site.

A Hazard Assessment of the risks associated with the storage and handling of chlorine at Shatin Water Treatment Works has been conducted for the Construction and Operational Phases of the SCL Project. The assessment results show that the societal risk lies within the ALARP region of the Hong Kong Risk Guideline (HKRG). An ALARP assessment has been carried out by identifying all practicable mitigation measures and assessing the cost effectiveness of each measure in terms of the risk reduction achieved and the cost of implementing the measures. As the result of the assessment, a number of recommendations have been made.

An EM&A programme will be implemented throughout the entire construction period to regularly monitor the environmental impacts on the neighbouring sensitive receivers. Any action required during the construction phase is also recommended for implementation.

The EM&A programme would include site inspection / audit and monitoring for construction dust, construction airborne noise, operation groundborne noise, water quality during dredging and updating changes as necessary. Details of the recommended mitigation measures, monitoring procedures and locations are presented in a standalone EM&A Manual.

5            Overall Conclusion

An EIA Report has been prepared to fulfil the requirements as specified in the EIA Study Brief No ESB-191/2008 and the TM-EIAO. All the latest design information has been incorporated into the EIA process. The aspects that have been considered in this EIA Report include:

·          Alignment evaluation;

·          Description of construction and operational activities;

·          Impact on cultural heritage;

·          Ecological impact;

·          Landscape and visual impact;

·          Air Quality impact;

·          Airborne noise impact;

·          Groundborne noise impact;

·          Water quality impact;

·          Waste management implications;

·          Land contamination impact;

·          Impact on hazard to life; and

·          EM&A requirements

Overall, the EIA Report has predicted that the Project would be environmentally acceptable and individual impacts are minimized with the implementation of the proposed mitigation measures for construction and operational phases. An environmental monitoring and audit programme has been recommended to check the effectiveness of recommended mitigation measures.

 

 


[1] The ultimate suitability of using either the DHS or HHS or a combination of both sites for train stabling would be subject to the findings of detailed engineering and EIA studies.