2. DESCRIPTION OF THE PROJECT

2.1 Key Project Requirements

2.1.1 The purpose of the Spur Line is to serve passenger needs while achieving safety and operational requirements. The purpose of the project and its compatibility with planned developments dictate to a certain extent the alignment of the Spur Line. The Spur Line is therefore designed based on the key project requirements as set down below. Various other constraints and requirements including engineering and environmental which are detailed in Section 2.9, have been considered to fine tune the design. These include:

(i) to locate the Lok Ma Chau Station to provide a cross boundary rail linkage with the mainland at Huanggang;

(ii) to provide a convenient connection at Sheung Shui Station for interchanging passengers to and from the East Rail; and

(iii) to make allowance for a station to serve the proposed Kwu Tung North New Development Area (NDA).

2.2 Site Location and Site History

2.2.1 The Spur Line is an extension to the northern end of the existing East Rail system. Figure 2.1 shows the proposed horizontal alignment and the Study Area for the Environmental Impact Assessment (EIA) Study. Also shown are the works areas, emergency access points (EAPs), the sections of ramp, cut and cover tunnel, bored tunnel and viaduct, and the outline of the proposed Lok Ma Chau Station. Figure 2.2 presents the vertical alignment of the Spur Line.

2.2.2 A detailed description of the background and history of the development of the Spur Line Project and the selection of the horizontal and vertical alignment is provided in Section 2.9 of this chapter. The following sections give a description of the features of the selected Spur Line route.

2.2.3 The proposed vertical alignment will descend from the at grade level at the existing Sheung Shui Station after diverting from the existing East Rail, onto two single track ramps. The southbound and northbound Spur Line track connections to the existing East Rail are staggered, the northbound track branching off before the southbound. This allows the northbound track to locate vertically below the southbound track, thus minimising the horizontal separation of the existing East Rail lines. The two tracks will enter the Eastern Portal at Chainages 30+420 (northbound track) and 30+762 (southbound track). The Eastern Ventilation Building will be located over the cut and cover section of the alignment. From Chainage 31+125 to 34+655, the two tracks enter twin 7.6m internal diameter (8.4m external diameter) bored tunnels located up to 30m below the existing ground level. Along the tunnel route, five emergency access points will be located, one east of the River Sutlej; one west of the River Beas, one at the west end of the future Kwu Tung station, one east of Pak Shek Au Road and one at the west end of the tunnel. Cross passages will be constructed at regular intervals between the twin bored tunnels to meet safety requirements.

2.2.4 The Tunnel Boring Machine (TBM) will be driven from the launching shaft at Sheung Shui, through to Chau Tau where, at Chainage 34+885, the western ventilation building will be constructed. In the area of the proposed Kwu Tung North NDA the shell of the future station will be constructed. The last section of the tunnel will be constructed using cut and cover techniques up to the western portal at Chainage 34+885. The tracks will then rise on an open ramp section to the viaduct abutment at 35+420. From this point, the viaduct rises to a top level of around 15mPD at which it continues to Lok Ma Chau station.

2.2.5 The location of the key elements of the scheme are shown in Table 2.1.

Table 2.1

Key Elements of the Spur Line Scheme with Chainages

Location of Key Elements
Element	Chainage	Distance
Start Ramp NB Track	CH 30+227
East Portal NB Track	CH 30+420
Start Ramp SB Track	CH 30+555
East Portal SB Track	CH 30+762
Start Launching Shaft	CH 30+985
End Launching Shaft	CH 31+125
CP1	CH 31+150	25m
CP2	CH31+390	240m
CP3	CH31+630	240m
CP4	CH31+870	240m
EAP East	CH 32+072
CP5	CH 32+110	240m
CP6	CH 32+350	240m
CP7	CH 32+590	240m
Start Station Box	CH 32+827	237m
End Station Box	CH 33+153
CP8	CH 33+380	227m
CP9	CH 33+620	240m
CP10	CH 33+860	240m
EAP West	CH 33+885
CP11	CH 34+075	215m
CP12	CH 34+275	200m
Start Recovery Shaft	CH 34+515	240m
Start Cross Over	CH 34+542.877	27.877m
End Recovery Shaft	CH 34+655	112.123m
End Cross Over	CH 34+660.898	5.898m
West Portal	CH 34+885
End Ramp	CH 35+200
Start Viaduct	CH 35+420
End Viaduct	CH 37+020

2.2.6 A number of works areas will be located along the alignment. These are indicated on Figure 2.1. These areas will be used for storage of materials, stockpiling of material removed from the tunnel (if disposal is delayed), water treatment plant, and general works activities.

2.2.7 The major length of the Spur Line route runs underground or on viaduct. The main areas of above ground works are at Sheung Shui, west of the River Beas, at Kwu Tung, Chau Tau and at Lok Ma Chau. Most of these areas are urban areas or semi rural areas with little ecological value. At some locations, areas of small industry may result in land contamination. The only area of ecologically sensitive land that will be directly impacted by the works is the fishponds at Lok Ma Chau. This area is part of the Wetland Conservation Area (WCA), as recommended by the Study on the Ecological Value of the Fish Ponds in the Deep Bay (Fish Pond Study). The WCA designation has been adopted by the Town Planning Board and promulgated under the Town Planning Board Guidelines for Application for Developments within Deep Bay.

2.2.8 The Lok Ma Chau fishponds are of importance because of their proximity and ecological linkage to the Deep Bay Ramsar Site. Details of these habitats and mitigation measures to minimise impacts on ecologically important areas are discussed in the Ecology Assessment in Chapter 4.

2.3 Nature, Scope and Benefits of the Project

2.3.1 The main elements of the Project include the construction and operation of a new railway that will connect from the existing East Rail to a rail passenger boundary crossing at Lok Ma Chau.

2.3.2 Only passenger train service will be operated on the Spur Line. Upon opening in 2007, the train frequency will be 6 trains per hour in each direction. This will gradually increase to the ultimate train frequency of 12 trains per hour in each direction in 2016. When the Spur Line is completed, trains to Lo Wu and Lok Ma Chau will be operated as split service direct from the existing Hung Hom station. The maximum speed of the trains operating on the Spur Line is 120 km/h. The Lok Ma Chau Boundary Crossing Point is assumed to be open from 0630 to 2330 hours. To accommodate the Boundary Crossing Point opening hours, the daily train service of the Spur Line will be provided between 0600 and one hour following the close of the Crossing Point.

2.3.3 Major benefits of the Project to the public include:

• Relieve congestion at East Rail Lo Wu Station,

• Provision of transport backbone for the proposed Kwu Tung North New Development Area,

• Increase the cross boundary rail capacity by establishing a second rail accessed cross boundary point,

• Enhance linkage with the mainland at Huanggang, where it is planned to base a future commercial centre for Shenzhen,

• Connect with proposed Shenzhen Metro System through a pedestrian footbridge, and

• An additional benefit of significant importance is the maintenance of KCRC's high safety standards, which are currently under threat by the increasing pressure at Lo Wu Station.

2.4 Size, Scale, Shape and Design of the Project

2.4.1 The major components of the Project include the construction and operation of a railway station at Lok Ma Chau and the section of railway alignment from Sheung Shui Station to the future Lok Ma Chau station. The major features of these facilities are described below.

• Lok Ma Chau Station: Consists of an island platform, two tracks and two concourse levels, one for arriving and one for departing passengers, KCRC public facilities, staff facilities, and plant and support facilities.

• Immigration and Customs Facilities: immigration halls for departing and arriving passengers, with facilitates for tidal flow, non-public immigration facilities, immigration and custom staff facilities, non-public custom facilities, security facilities, quarantine facilities and Department of Health facilities.

• A permanent way of a total route length of 7.4 km between Lok Ma Chau and Sheung Shui Stations, 4.3 km of which will be constructed in tunnel, 0.9 km on ramps or at grade, and the remainder on viaduct. The project includes construction of diaphragm walls as the track descends at Sheung Shui and Chau Tau, cut and cover tunnels, twin bored tunnels from Sheung Shui to Chau Tau, the station box at Kwu Tung North and viaduct construction. The permanent way will be complete with traction power supply.

• A two level footbridge linking Lok Ma Chau and Huanggang Stations.

• Landscaping works and noise barriers where required. All other mitigation works as recommended in the EIA.

• Diversion of a 132kV electricity power line within the Wetland Conservation Area.

• The main sewers on San Wan Road may need to be temporarily diverted to allow realignment of the existing East Rail tracks. The Dongjiang Raw Water Mains near the existing Sheung Shui Station have to be diverted to allow construction of the cut and cover section of the tunnel. Works need to be carried out during the Dongjiang supply shut down in December each year. This will likely take place in December 2002.

• The physical landtake required for the terminus has been minimised through careful design during the Spur Line design development. The final layout is the smallest area that still accommodate the needs of the station, the EVA and the significant area required for the customs and immigration facilities.

2.5 Project Timetable

2.5.1 It is assumed that the necessary land will be available for this to start in the third quarter of 2002. The remaining land will be available by January 2003 for works on the East Rail diversion, tunnel approach sections, EAPs, Kwu Tung station box, viaduct construction and Lok Ma Chau station. Access to the uptrack will be available by April 2006, enabling rail systems installation completion by July 2007 when the Spur Line is planned to open.

2.5.2 A preliminary project programme has been created, as summarised below. This programme will be utilized as the basis for this assessment.

Table 2.2

Preliminary Summary Construction Programme

Construction Activity	Estimated Dates
Excavation of the TBM launching shaft	July 2002 to May 2003
Uptrack tunneling	September 2003 to September 2004
Downtrack tunneling	December 2004 to November 2005
Cross Passages construction	December 2005 to April 2006
Station Box construction	January 2003 to July 2005
Ventilation Building and EAPs	January 2003 to April 2007
Western Approach Tunnel	January 2003 to September 2005
Eastern Approach Tunnel	January 2004 to December 2005
Water Mains Diversion	June 2002 to May 2003
Viaduct Construction	December 2002 to June 2005
Lok Ma Chau Station Construction	September 2002 to June 2006
E&M works and ROS Commissioning	February 2006 to July 2007

2.6 Means of Implementation

2.6.1 The Spur Line will be constructed and operated by KCRC. The project will be implemented by means of a design and build contract for the tunnel section, and two detailed design contracts followed by construction contracts for the viaduct and Lok Ma Chau station The design of the project is underway and the work will be tendered out for construction following the completion of the detailed design works.

2.7 Related Projects

2.7.1 At the time of this Environmental Impact Assessment Report (EIA), two planning studies are in progress, one for North-West New Territories (NWNT), one for North-East New Territories (NENT). The proposed development area for the Planning and Development Study on NWNT is outside the Spur Line Study Area and will therefore not be evaluated in this report There will be a close interface between the Spur Line and the ongoing Planning and Development Study on NENT (the NENT Study). The proposed Kwu Tung North New Development area (NDA) was presented to the public in October 1999. Based on the Preliminary Layout Plans subsequently prepared for the NDA, the EIA is currently under preparation.

2.7.2 As the Spur Line is in tunnel through the Kwu Tung North NDA, there will be no above ground impacts related to railway noise on future sensitive receivers in the development. Potential groundborne noise impacts from the operation of the railway will be mitigated through the incorporation of a Floating Slab Track (FST) through the NDA section of the alignment. The removal of all potential noise impacts on future developments in the area provides much greater flexibility for the planners of the Kwu Tung North NDA and is a key benefit of the tunnel option.

2.7.3 At the Lok Ma Chau end of the alignment, a further interface may occur with the Main Drainage Channel for San Tin. Construction of the main channel will be ongoing during the construction of the Spur Line. Mitigation measures for each project should not compromise the other project and where possible, should be complimentary. These concurrent projects are shown on Figure 2.3.

2.7.4 The proposed Lok Ma Chau Station will be connected to the Shenzhen Metro’s Huanggang Station on the mainland side via a new footbridge for rail passengers. Close liaison with the Mainland Authorities to ensure proper co-ordination between the Spur Line and the Shenzhen Metro projects will be maintained.

2.8 Type, Scope, Scale, Frequency and Duration of the Construction and Operational Activities

2.8.1 The construction activities for Spur Line comprise works related to the existing East Rail connection, tunnel construction, Kwu Tung Station shell, relocation of Lok Ma Chau Road, viaduct construction, footbridge across Shenzhen River and foundation and infrastructure works at Lok Ma Chau station. These works require the following construction activities:

• Diversion of East Rail to the east. This will involve the physical removal of tracks to the east of the existing alignment.

• Diversion of main sewers on San Wan Road. To protect the main sewers, they will have to be relocated east temporarily. This will involve excavation and earth movement.

• Temporary diversion of San Wan Road. Excavation works will be required, followed by reinstatement works at a later stage.

• Construction of embankment and encroachment into San Wan Road. Earth movement and ground preparation works will be required.

• Temporary moveable steel enclosure over new East Rail alignment. Works include fabrication and physical placement of enclosure and relocation of the enclosure as the works move alongside the existing alignment.

• Removal and reinstatement of concrete footbridge. This will require demolition works followed by concreting works to reinstate the bridge.

• Diaphragm walling. This will involve excavation, concreting works, earth movement and use of bentonite, including cleaning and recycling plant.

• Construction of cut and cover tunnels. Excavation works, earth movement, construction of floor and roof, reinstatement of the land and landscaping.

• Diversion of water mains. Pipelaying works, thrust blocks and connection to existing water mains at key dates dictated by Dongjiang water mains shutdown.

• River Sutlej works. Excavation into alluvial phase of channel floor, earth movement, sheet piling, concreting, reinstatement works.

• Ventilation buildings. Excavation works, site formation, concreting works, pond filling at western ventilation building.

• Construction of EAPs. Site formation, excavation to tunnel depth, concreting works, bored piling works, earth movement, landscaping.

• Construction of 3.5 km of twin tube tunnels by Earth Pressure Balance Tunnel Boring Machine (TBM) and installation of pre-cast lining segments.

• Construction of cross passages. Excavation, jet grouting (surface or below ground) or ground freezing (below ground).

• Construction of Kwu Tung station box. Excavation, earth movement, piling, concreting, reinstatement, landscaping.

• Construction of TBM Launching and Retrieval shafts. Excavation, earth movement, diaphragm walling, concreting, reinstatement, landscaping.

• Construction of tunnel approach ramps. Earth movement, construction of retaining walls, landscaping.

• Construction of viaduct. Excavation, earth movement, piling, pier construction, deck erection, reinstatement, landscaping. Dredging and filling of ponds for temporary works (along alignment) or permanently (at Lok Ma Chau station).

• Widening of Lok Ma Chau Road. Excavation, traffic diversion works, reinstatement works.

• Diversion of 132kV electricity power line.

• Construction of station. Filling, wick drain installation, earth movement, piling, concreting, infrastructure works, landscaping.

• Construction of footbridge connecting Lok Ma Chau and Huanggang Stations. Excavation, piling pier construction, deck erection/construction, reinstatement, landscaping.

• Construction of mitigation measures. These works will vary from ecological mitigation measures, such as wetlands and landscaping, to construction of noise barriers on the viaduct section of the alignment.

2.8.2 A description of the type of works involved in the construction of the key structures is described below. The tunneling works will take place from east to west, with much of the above ground works carried out around Sheung Shui. The following description outlines above ground activities at each end of the alignment and a description of the tunneling operation starting from Sheung Shui.

Eastern End Structures and Works Involving above Ground Works

Initial Works required for Spur Line Construction

2.8.3 Prior to the construction of the Spur Line tracks, diversion of the existing East Rail is required. This will require overnight operation to complete the works. The existing East Rail tracks will be slewed to the east, impacting part of San Wan Road and requiring the diversion of the mains sewer at this location, to a position east of the works area. The rail works must be done in the non-operational period, including the movement of the overhead power lines to allow normal operation during the construction period. A large moveable or travelling enclosure will be constructed over the operational lines to protect the operational East Rail service from being affected by construction works carried out for Spur Line construction.

Ramp Section

2.8.4 At the point where Spur Line tracks leave the existing East Rail, turnouts will be installed in the tracks the north bound (uptrack) descends before the south bound (downtrack). From here, the north bound Spur Line track (uptrack) will ramp down at a gradient of no more than 3%. The south bound line (downtrack) will ramp down at the point when the uptrack has descended sufficiently to allow placement of a slab above the rail structure gauge. The downtrack will descend on a ramp on top of this slab, resulting in an over and under stacked train arrangement that will minimize land requirements between the water mains to the west and the mains sewers to the east. The ramps will be constructed using permanent diaphragm walls and a surface slab.

Cut and Cover Tunnel

2.8.5 The stacked box tunnel configuration will be constructed using permanent diaphragm walls and slabs. Three out of every four diaphragm wall elements is taken down to rock level for support.

East Ventilation Building

2.8.6 Within the cut and cover section the Eastern Ventilation Building will be constructed. The works will require permanent diaphragm walls to be excavated to the level of the two tunnel boxes (at different levels at this location).

Emergency Access Point

2.8.7 East of the River Sutlej, close to the launching shaft location, an EAP will be constructed. The works will require excavation, and diaphragm walls to the level of the two tunnels.

TBM Launching Shaft and Facilities

2.8.8 A launching shaft is required at the eastern end of the tunnel drives, from which to start the tunneling operation. The works area adjacent to this shaft will house the necessary facilities for the works, namely, storage area for precast concrete tunnel lining segments, TBM workshop, mortar plant, bentonite production plant, water treatment facilities and necessary conveyor equipment to bring waste to the surface for storage and disposal.

2.8.9 The launching shaft itself will adopt diaphragm walls construction to form a water tight box. After the tunnel drive is complete, the cut and cover reinforced box structure can then be commenced in the shaft. Once complete, the shaft can be filled and the diaphragm wall can be broken down to a suitable level below ground.

River Sutlej Crossing

2.8.10 The ground cover at the river crossing above the crown of the excavation will likely be less than the required cover of one tunnel diameter. To ensure stability during excavation and to allow future improvement works by DSD on the river bed, the soils above the tunnel may require pre-treatment. This treatment will consist of either deep grout injection or excavation followed by filling with a lean mix concrete box to form a solid box unit through which the TBM can bore. In both cases, the low flow channel will require relocation within the section of the channel not being worked. If the works are carried out using lean concrete mix, excavation will be carried out within sheet piles to a 7m depth, the void filled with lean mix concrete and the river bed reinstated with a slab of concrete. The excavated alluvial material will be drained before disposal.

Utilities

2.8.11 The water mains will be diverted through a small section of their length while the cut and cover operation is being carried out. The mains in other areas of the works will be protected by construction of a frame over the pipes.

2.8.12 The following table summarizes the sequence of construction activities to be carried out at the eastern end of the alignment.

Table 2.3

Construction Sequence - East End of Spur Line Alignment

Stage No.	Stage Description
1	• Existing East Rail Up & Down Lines and siding remain in operation. • Diversion of 1.8 m dia. Sewer • Demolition of existing footbridge • New ER crossing & turnback siding north of river crossing • Temporary diversion of both East Rail Up & Down Lines eastward encroaching into San Wan Road. Elimination of existing siding • Complete construction of diaphragm wall and tunnel roof from receiving shaft, required for local diversion of all five water mains near launching shaft
2	• Carry out permanent local diversion of all water mains starting CH 30+800 towards launching shaft • Continue construction of diaphragm wall and tunnel structure from west side of the diverted ER Up Line
3	• Upon completion of civil structure, divert ER Up Line to permanent position
4	• Divert ER Down Line to permanent position

Middle Section of Alignment

Kwu Tung Station Enabling Works

2.8.13 A box for the future Kwu Tung station will be constructed using diaphragm walls excavated to rock head. The box may be excavated before the TBM passes through, or after the TBM has passed through, in which case the precast lining units will be removed during excavation. Bored piles will be driven concurrent with the diaphragm wall to provide the basis for the future station construction. As described below for the launching shaft, break out and break in ground treatment will be required to enable the TBM to enter and exit the station box safely and without wall collapse. Even if the TBM drives through the area before excavation on the first drive, it is likely to pass through an excavated box of the second drive. A temporary floor slab will be required to be constructed below the level of the second TBM drive and it will need to incorporate a suitable 'bedding" on which the TBM can pass over.

2.8.14 A temporary steel strut bracing system will need to be incorporated at a level just above the TBM envelope. This steel strutting will be of modular segmental form, to assist in installation between the partially completed beam network above. There will also be a ventilation building above ground at the west end of the station box.

Emergency Access Point (EAP) shaft at Pak Shek Au / Emergency Access Point (EAP) shaft at Ho Sheung Heung

2.8.15 Two Emergency Access Points (EAP) shafts will be located along the alignment, one west of River Beas and the second at Pak Shek Au. These will be constructed along the length of the tunnels using diaphragm walls and where the ground conditions allow, will be excavated to rock head. The EAP site will be used for a bentonite production plant and to site mucking out vehicles. The connecting passage between the shaft and the tunnel will be constructed using ground treatment in a similar way as used for constructing cross passages.

2.8.16 There are two options for constructing the EAP shafts. The first involves the construction of a box configuration or diaphragm walls to form the permanent shaft. The other is to use a slightly larger circular diaphragm wall. No strutting will be needed. Both involve excavation and muck out from the surface and installation of permanent work from bottom up in a conventional manner.

Western End Structures and Works involving above Ground Works

TBM Reception Shaft

2.8.17 The 45m diameter TBM reception shaft is located within Chau Tau, where the future Railway Emergency Repair Material Storage Yard will be located. The shaft will be constructed by excavation and construction of diaphragm walls to bedrock. Excavation will be required in two phases to the first tunnel level for removal of the TBM cutter head for the first drive, followed by excavation to a deeper level for the second tunnel drive. After boring, box tunnels will be constructed inside the shaft, then permanently sealed below ground level. To facilitate the break out process for the TBM, pretreatment is required. This will comprise a combination of slurry cut-off wall and localized jet grouting over a length of between 15 and 18 m.

2.8.18 The area around the shaft will be raised to avoid flooding during the operation and later for use as a Storage Yard. Footpaths will be formed around the site as required.

Cut and Cover Tunnel

2.8.19 Works for the construction of the cut and cover section at the western end are complicated by the network of existing channels and accesses that traverse the site. Diversion of adjacent channel and the vehicle access to adjacent sites is necessary. The ground level in this area is too low to avoid flooding and will be built up to avoid this risk. The cut and cover section starts at chainage 34+530, the western section of the TBM recovery shaft. Construction will involve diaphragm walling, with a top and bottom slab to support the walls and a centre wall to divide the tunnel into the two separate "boxes".

2.8.20 A minimum cover of 1.0 m will be placed as backfill to reinstate the surface to original ground level. This will be sufficient for paving and landscaping around the western ventilation building. At the ventilation building, the tunnel box becomes an open-top section with high level cross-beams or "flying beams' . At chainage 35+075 km the alignment becomes a cutting section with vertical retaining walls.

West Ventilation Building

2.8.21 The western ventilation building will be located west of the recovery shaft, at chainage 34+885. The works required for this ventilation building are similar in all aspects to the East Ventilation Building.

Diversion and Widening of existing Lok Ma Chau Road

2.8.22 The Lok Ma Chau Road is to be upgraded to a 6.75 m wide road as part of the Project to form the access to the Lok Ma Chau Station. The Lok Ma Chau Road will be raised along the south side of the tunnel structure to a point where it can cross the tunnel structure and reconnect to the existing road alignment. It is anticipated that a section of bridge will be constructed as part of the tunnel structure.

Diversion of 132kV cable next to San Sham Road, Lok Ma Chau

2.8.23 The existing 132kV main located in the WCA immediately adjacent to the east side of the LMC Boundary Crossing will be removed to facilitate the viaduct construction. The existing cable is located underground within the boundary control area, but immediately rises and runs overhead on pylons thereafter. The 132kV cable route will be dismantled and the new cable alignment will run in the footway alongside the reconstructed Lok Ma Chau Road. The underground cable will be restored to an overhead connection in the immediate vicinity of the Fanling Highway. Figure 2.5 highlights the dismantling of the existing 132kV cable and the alignment in the new Lok Ma Chau Road, part of which will be in the WCA.

Diversion of Upstream Tributary of Chau Tau Channel

2.8.24 The upstream tributary of the Chau Tau Channel at chainage 34+850 km will also need a temporary and permanent diversion. The main Chau Tau Channel at chainage 35+400 km does not require diversion as part of the works. However, it is close to the abutment for the viaduct and a box structure under the railway will need to be provided.

Viaduct Interface (including ramped section)

2.8.25 Viaduct will start at chainage 35+420 km. This is positioned to allow for a 1.0 m high pier and a 3.0 m deep viaduct box. The ramped section of the alignment leading to the abutment will be constructed between retaining walls. Diaphragm wall or piled construction will overcome the differential settlement between ramp and viaduct.

2.8.26 A cut-off channel will be constructed at the point where the alignment meets existing ground level. The open section of construction that is below ground level will require flood protection. A parapet to 1.8 m above the surrounding ground will be required where the alignment is adjacent to the existing Lok Ma Chau Road.

2.8.27 The structure will be supported on diaphragm wall to avoid differential settlement problems. In some cases a retaining wall will be necessary. Where alignment is deep, "flying beams" will be used.

Viaduct Construction

2.8.28 The viaducts will be constructed through a staged process of piling, pile cap construction, pier construction, following by erection of the precast deck units onto the viaduct columns. Several viaduct piers will be constructed at the same time, in different stages of activity.

Lok Ma Chau Station Construction

2.8.29 The station is located on an area of very soft marine mud that will require stabilization before station construction can begin. Mud removal will be avoided by a consolidation process, involving placing wick drains into the mud and placing fill on top. The surcharge area (where fill has been placed as part of the consolidation process) will extend beyond the station footprint and will be removed at a later stage for construction of the ecological mitigation area around the station. The station footprint has been minimized to reduce impacts on this sensitive ecological area. The station infrastructure will comprise a 4 storeyed building with facilities for immigration and customs control, a sewage treatment plant, external paved areas including an emergency access road, and landscaping.

Footbridge across Shenzhen River Connecting Lok Ma Chau and Huanggang Stations

2.8.30 A two-level footbridge will be constructed across the Shenzhen River to link up the Lok Ma Chau Terminus and the Huanggang Station of the Shenzhen Metro System. The footbridge construction will mainly involve piling, pile cap construction, pier/pylon construction and deck erection/construction.

Tunneling Operations

2.8.31 Once assembled in the launching shaft, the TBM will commence excavation at atmospheric pressure using the screw conveyor to extract the excavated spoil . The first 15 to 18 m of the tunnel will be pretreated to ensure stability of the crown and excavation face and importantly, to minimize permeability to prevent groundwater from flowing into the shaft. Initial ground treatment will form a water tight block between 15 m to 18 m long, to enable the length of the TBM shield plus two full TBM shield lengths to withstand the confining pressure necessary to balance water pressure as the TBM excavates out of the pre-treatment zone. This is likely to be carried out by forming a slurry wall cut-off with soil treatment, such as jet grouting substitution, of the upper section of the tunnel envelope for stabilization of crown and face during the break in-phase. Due to the forces encountered by the Launching shaft frame, mini pile or H-pile foundations may be necessary for stability.

2.8.32 The tunneling operation will extend from the launching shaft at Sheung Shui through to the reception shaft at Chau Tau. The majority of the route will be through Completely Decomposed Volcanic Tuff (CDV) with a small amount of ground being Volcanic Tuff Bedrock. In the CDV phase, the TBM machine will be operated in Earth Pressure Balance mode in which the chamber behind the rotating cutter head is maintained at a defined pressure through the addition of sufficient water to the soil at the face, to form a paste against which the machine can maintain pressure. The water-soil mixture is removed from the chamber through the rear bulkhead using a long screw conveyor system, through which excess pressure above atmospheric is dissipated before the material is placed onto a belt conveyor that passes the full length of the tunnel. When brought to the surface by the conveyor, the water/soil mix is placed in soil basins where it is allowed to settle. The remaining water after settlement, is passed through a drainage system to the water treatment plant where flocculants are added to facilitate settlement. The treated water is discharged to a licensed discharge point.

2.8.33 The use of bentonite will depend on the nature of the material being excavated. If the material is mixed, i.e. rock and soil, the use of a stabilizing material, such as bentonite may be required to avoid wall collapse. After the TBM has passed each section, the precast concrete segments are installed behind the cutter head and the outer space mortar grouted to ensure water tightness.

Cross Passages

2.8.34 Thirteen cross passages (CP) will be formed between the two tunnels. Eleven of these are in soil, which needs to be stabilized before excavation can commence. Formation of the CP in rock requires only minor rock grouting works to minimize water ingress.

2.8.35 For the remaining CP outside Long Valley, soil stabilization comprises jet grouting from above at very high pressures from the surface to form a block of grout strengthened soil. These works require an area of approximately 23m across the two tunnel widths, and 10m along the length of the alignment. Grout will be drilled into a 12m deep box, extending from above the tunnel soffit to below the tunnel invert. This procedure will be carried out before the tunneling operation reaches this site.

2.8.36 No grout will be used to stabilize the soil under the Long Valley wetland to avoid inadvertent blocking of any aquifer. The soils will be stabilized from below and groundwater ingress minimized from within the first tunnel drive by using ground freezing or compressed air techniques.

2.8.37 These activities will be carried out at various times depending on constraints set by KCRC East Rail and other government departments. Table 2.2 shows the planned duration of each set of activities during the overall construction period. This is described more fully in the chapter on Construction Noise where concurrent works are assessed for their noise level.

2.9 Background and History of the Spur Line

2.9.1 Introduction

This section describes the background the history of the Spur Line project, from its initial inception to the present EIA study. An important part of the overall process was the selection of the vertical and horizontal alignment of Spur Line. The history of the initial alignment selection, the EIA rejection and Appeal process and the subsequent decision of the alignment selection is described in this section.

2.9.2 Background

2.9.2.1 Planning of the Spur Line has taken place over a long period of some 10 years, in order to identify the most suitable route and method of construction. In determining the route, consideration was given to a great many factors including: environmental issues, cultural heritage issues, railway engineering design requirements, land use and planning requirements and physical constraints. All of these issues were addressed to ensure the provision of a safe and reliable operating railway. The initial proposal for the development of the Spur Line was presented in the final report of the Railway Development Study in May 1993. The project was further progressed as part of the West Rail (Phase II) project until the upsurge in patronage crossing to Lo Wu Boundary Crossing at a double digit rate a year since 1996 that required the Spur Line to be progressed ahead of the rest of West Rail (Phase II). This initial proposal showed the railway on viaduct across the Long Valley wetland area, at grade through Kwu Tung and rising again onto viaduct to Lok Ma Chau where the station terminus was proposed. This alignment represented the optimum route based on consideration of project objectives, design criteria and constraints at that time.

2.9.2.2 In November 1998 a Preliminary Project Feasibility Study (PPFS), which evaluated the engineering and environmental feasibility of the potential route was completed by KCRC and presented to government. During the PPFS study, modifications were made to the horizontal alignment at the western end of the Spur Line to minimize impacts on the Lok Ma Chau fishponds area and minimize works in the particularly soft muds of the area. The selection of this horizontal alignment is described in Section 2.9.5.

2.9.2.3 Between May 1999 and June 2000, an Environmental Impact Assessment was undertaken for the viaduct alignment which was considered to be the most suitable option among 9 options considered, after taking into account all the constraints of the Project. Following the public consultation period for the EIA, EPD declined to approve the EIA report and award an Environmental Permit. The judgement on the ensuing Appeal against this decision recognized that it is government policy to implement the Spur Line. The Board suggested that in considering whether an alternative was ‘practical and reasonable’, apart from environmental acceptability, other factors that should be considered included engineering constraints, extra-time involved, additional cost and government policy. The Appeal Board concluded that, after all the evidence had been presented, only three options could be considered as being viable alternatives for the Spur Line alignment. On these alignments, the judgement stated:

We have each reached a view on the practicability and reasonableness of the alternatives advanced. For what it is worth we disclose it. On all the evidence we heard the possible alternatives which could be practical and reasonable were reduced to three:-

(a) the viaduct as proposed;

(b) the bored tunnel on the same alignment; and

(c) the Northern Link.

The Northern Link, however, is outside any useful consideration for this appeal. This alternative would require a major change in government policy even if it would be possible to implement it in a timely fashion to satisfy the need. On [expert witness] evidence we think the bored tunnel to be feasible from an engineering point of view…… However, if the additional cost is anywhere in the region of HK1.4billion as estimated…., this would put the reasonableness of this alternative in doubt when the viaduct remains a possible solution……

We believe that the viaduct as now proposed may have merit. Our view is that with the expertise and long-term financial support available the mitigation is likely to succeed.

[Note: gaps in text are due to removal of named individuals which are not relevant to this EIA]

2.9.2.4 Although the Appeal Board considered the viaduct to be a viable solution, they considered that KCRC had not sufficiently demonstrated that the mitigation would be successful and it required further studies to enable confidence to be given to this proposal. The Appeal Board considered that the Northern Link was outside any useful consideration for that appeal. The Board was aware that implementing the Northern Link in lieu of Spur Line would require a major change in government policy, even if it were possible to implement the Northern Link in a timely fashion. According to Government’s published documents, the Northern Link, which is recommended in the Railway Development Strategy 2000 is designed as a long term complement to, but not a replacement of, the Spur Line project. Even if the NOL was constructed first, the Spur Line would still be require to provide the strategic link of East Rail and West Rail in the Northern part of the New Territories. Furthermore, building the Northern Link would at least take seven to eight years as the project is only at the conceptual stage.

2.9.2.5 Following the result of the Appeal, KCRC has been in extensive discussions with AFCD and EPD on the way forward for the Spur Line project. Continuation with the viaduct option for Spur Line would require several years of further work, with no guarantee of the acceptability of the project and associated mitigation proposed by all stakeholders involved. Consequently, KCRC has reconsidered the possibility of avoiding impacts to Long valley completely by placing the Spur Line in tunnel from Sheung Shui to Chau Tau. This option, although considerably more expensive than the viaduct option, will remove the major objections raised during the public consultation and appeal process and will provide confidence in the protection of the environment.

2.9.2.6 The factors that have guided the determination of the vertical alignment, taking into account the recent history of the EIA process, are described in section 2.9.6. During the planning process, alternative horizontal alignments were also considered, and the reasons for selection of the present option are explained in Sections 2.9.4 and 2.9.5.

2.9.3 Objectives, Criteria and Constraints

In both the early planning stages and in subsequent revisions of the Spur Line alignment, the following objectives, criteria and constraints were considered.

2.9.3.1 Environmental Objectives

• Minimization of impacts on ecologically sensitive wetland along the proposed route. Areas that could be impacted include Long Valley, fishponds at Lok Ma Chau and other wet agricultural land within the Study Area. These areas are shown on the general habitat map in Figure 4.1 of the Ecology Chapter.

• Avoidance of disruption to any ecological corridors and important habitats.

• Avoidance of impacts on any existing communities, monuments, historical buildings, cultural heritage and archaeological resources. Known sites requiring conservation include (these are indicated in the Cultural Heritage Assessment Chapter of this EIA):

¨ the historical village of Ho Sheung Heung;

¨ an important burial site at Kwu Tung;

¨ Chau Tau village;

¨ an important burial plot west of Chau Tau;

¨ San Tin village (which is one of the earliest inhabited villages in Hong Kong.

• Minimization of construction and operational noise arising from railway and station construction.

• Minimization of impacts to waterbodies along the alignment and air quality within the area.

• Minimization of landscape and visual impacts on existing village zones by the careful location of the railway alignment.

2.9.3.2 Planning and Land Use Considerations

The chosen alignment took into account the following issues -

• The proposed development of a New Development Area centred on a new railway station in the area of Kwu Tung

• Minimization of land resumption (e.g. by making use of Government land rather than private land wherever possible)

• Minimization of impacts to existing public utilities and infrastructure

• Minimization of impacts on existing and planned development projects

• Allowance for future connection with the proposed Northern Link

2.9.3.3 Safe Railway Operation

• The point at which the Spur Line branches off must be located on a straight section of the existing East Rail to ensure safe railway operation.

• The tracks passing beneath the operational East Rail must have a clearance of at least one tunnel diameter from the existing East Rail line. If tracks pass over the top of East Rail, the clearance must comply with KCRC’s safety requirements.

• Maximum gradient constraints require the railway descending beneath East Rail or ascending over East Rail to begin its descent 500m south of the crossing point.

2.9.3.4 Operational Requirements

• Connection of the Spur Line to East Rail must be north of Sheung Shui Station. This requirement is based on the need to maintain the current level of railway service for passengers at Sheung Shui.

• Spur Line must connect to Huanggang Station and the Shenzhen Metro.

• A double crossing must be located on the Spur Line at the nearest location possible to Sheung Shui station. This double crossing must be located on a straight section of track for safety reasons.

• Maximum gradient should not exceed 3%.

• Minimum curve radius is 300 m.

2.9.3.5 Engineering Requirements

• Disruption of drainage paths must be avoided, particularly in the flood plain of the Beas and Sutlej Rivers to avoid flooding problems in the northern New Territories.

• Changes to the hydrological regime in Long Valley must be avoided to prevent changes in the wetland characteristics of the valley.

• Sufficient vertical clearance must be provided during tunneling or on viaduct to allow for the local roads at Kwu Tung and Lok Ma Chau.

• Provision must be made for the planned expansion of boundaries of the Lok Ma Chau Vehicle Boundary Crossing and to minimize the uptake of fishpond area around Lok Ma Chau.

• Sufficient clearance must be provided for the two 2.2 m diameter water pipes of Water Services Department at Pak Shek Au.

• Sufficient overhead clearance is required below the railway in crossing San Sham Road.

• Sufficient overhead clearance is required between the railway and the proposed pump house and maintenance access road ancillary to the Eastern Main Drainage Channel.

2.9.3.6 Social Considerations

• Private land resumption especially in built-up areas has to be avoided as far as practicable to minimize impact on occupants.

• The alignment should be located as remote as possible from village areas to minimize impact on residents.

• The landtake for the project should be minimized to reduce land clearance impact.

• Taking into account all these requirements, several alternative alignments at the east end of the Spur Line were considered at the early planning stage, both for the east and west ends of the alignment. A summary of these options is given below.

2.9.4 Determination of Spur Line Alignment at East End

2.9.4.1 Recognizing the ecological importance of Long Valley, an area of about 34 ha, five alternative route options were evaluated to cross this area. Two of the options, the Northern Route and the River Beas Route would cross the northern sections of Long Valley, the former passing close to Ho Sheung Heung village with considerable visual impacts, and the latter following the retrained River Beas, and impacting areas of ecological mitigation established by other projects. In both cases the branching off from the existing East Rail track would require complex engineering work and would require removal of part of the Sewage Treatment Works.

2.9.4.2 Two routes were considered that would cross the southern part of Long Valley. One of these routes, Southern Route 1 would require demolition and reinstatement of the Po Shek Wu Road Bridge, a major arterial route for traffic crossing the border at Man Kam To. Southern Route 2 would compromise the requirement to branch off the existing East Rail north of Sheung Shui station and would also have considerable impacts on several villages within the southern part of Long Valley. A detailed evaluation of the relative merits and disbenefits of these alignments in produced in Appendix A2.1. These routes were considered by EPD and the EIA Appeal Board in the context of the previous EIA submission.

2.9.4.3 The selection of the Central Alignment, which is presented in the current EIA report, was based on its compliance with all the planning, land use, railway safety and operations and general engineering requirements set down in sections 2.9.3.2 to 2.9.3.6. In particular the Central Alignment begins at a straight section of East Rail, it also avoids the constraints arising from Shek Wu Hui Sewage Treatment Works and the Sheung Shui Slaughter House which block other routes.

2.9.4.4 Selection of the vertical placement of the railway on this selected alignment is described in Section 2.9.6.

2.9.5 Determination of Horizontal Alignment at West End

2.9.5.1 Three possible alignments were considered for the western end of the Spur Line (Chau Tau to Lok Ma Chau station) and are shown on Figure 2.4. The viability of each alignment was examined against a selection of criteria to assess the relative merits of each option. Engineering constraints, including the presence of very soft ground in the Lok Ma Chau area, which may affect construction works were a serious consideration. The selected alignment (revised Alignment 2) minimizes this problem. Land issues have contributed to further localized revisions to this alignment that will require the temporary drainage of additional fishponds in the Sam Po Shue area. These fishponds, along with others disturbed by the project, will be reinstated upon completion of all works. The entire western end of the rail alignment will be elevated on viaduct.

2.9.6 Determination of Vertical Alignment

2.9.6.1 Selection of the Central Alignment for the Spur Line route across Long Valley required consideration of the optimum vertical profile for the railway. As described in Section 2.9.2, the original proposal was for a viaduct across Long Valley on the basis that raising the railway above ground level and providing compensation below and away from the viaduct would overcome the perceived and possible impacts from the railway operation on the ecology of the area. As described, the certainty of such ecological mitigation proposals being successful was in doubt by a number of the stakeholders in the overall process, without a considerable amount of further work being carried out. The following two tables (Tables 2.4 and 2.5) compare the impacts and/or benefits from the viaduct, at grade and tunnel options of the Spur Line Central Alignment option from both an environmental and engineering point of view. These tables take into account the outcome of the EIA for the viaduct option.

2.9.6.2 Development of the Spur Line vertical alignment has taken into consideration the various problems and benefits related to underground, elevated and at grade forms of construction. These were compared within the context of the environmental and engineering requirements of the Spur Line and in the light of recent events related to the EIA for the viaduct option. (Tables 2.4 and 2.5)

Table 2.4

Comparison of Environmental Impacts Related to Vertical Alignment Options

Environmental Impact	Underground	At Grade	Elevated
Wetland Loss	Possible draw-down of water table may affect wetland. Significant Impacts if cut and cover method of tunneling used. Can be overcome using Earth Pressure Balancing Machine TBM method.	All wetland along the 32 m wide corridor of the alignment would be impacted.	Ground level impact limited to column foundations. Potential disturbance to the fauna of Long Valley potentially very difficult to mitigate for. Complexity of wetland habitats requires significant field data to demonstrate success of wetland creation. Potential unacceptable delay to project.
Ecological Impacts	Major disturbance during construction if in cut and cover. Minimal disturbance using EPBTBM.	Severance of existing ecological corridors, across Long Valley in particular.	Potential fragmentation impacts difficult to mitigate. Habitat loss can be mitigated through protection during construction and compensation for valuable habitats. Viaduct option generally minimizes habitat loss.
Operational Noise	Minimal.	Extensive at source mitigation needed to minimize impact	Multi-plenum design adopted to successfully minimize impacts.
Construction Noise	Considerable noise associated with diaphragm walling for cut and cover construction. Localized noise only for TBM method. Long construction period.	Extensive site formation throughout the alignment. Long construction period.	Viaduct decks manufactured off-site, shipped in by barge and transported by road. Impact limited and transient as only occurs during column construction. Potential disturbance during column construction in Long Valley difficult to mitigate.
Water Quality	Construction run-off minimal. Use of bentonite needs to be carefully controlled. Minimal operation phase impact.	Potential impacts on surrounding watercourses during the construction and operation.	Potential for impacts during viaduct column construction.
Visual And Landscape Impact	Minimal.	An at grade railway can be adequately landscaped to minimize impacts.	High visual impact in rural and predominately flat landscape of Long Valley and Lok Ma Chau.
Fugitive Dust During Construction	Potentially significant as cut and cover tunneling will require excavation of large quantities of spoil. TBM method can allow more controlled material removal.	May be significant during site formation.	Minimal.
Construction Waste	Significant. Large quantify of soil is expected to be unsuitable for re-use on site. Suitable site for dewatering and disposal needs to be found.	Some soil may not be suitable for reuse on site and has to be disposed. Quantity not as significant as tunneling.	Minimal.
Cultural Heritage And Historical Buildings	Minimal because the tunnel would be too deep underground to affect such resources.	May affect burial plots at Pak Shek Au and Chau Tau.	Minimal.

Table 2.5

Comparison of Vertical Alignment Selection within

Engineering Constraints

Engineering Constraint	Underground	At Grade	Elevated
Drainage	Tunneling can only be safely carried out in floodplain areas of Long Valley and Lok Ma Chau using complex tunneling technology including EPBTBM.	Potential restriction of drainage in low-lying areas. Potential flooding problems of the permanent way, posing a safety and operational risk.	Minimal disruption of drainage.
Impact on existing railway operation	Tunneling can only be carried out beneath the existing operating East Rail line at Sheung Shui if the existing operating East Rail is realigned.	The railway cannot be at grade as it crosses the existing East Rail line.	A viaduct is the easiest means to cross the existing East Rail line.
Clearance requirements	Bored tunneling requires a minimum soffit to ground surface of 1 tunnel diameter unless alternative soil treatment is introduced.	At grade is required to clear Po Shek Wu Bridge at Sheung Shui.	Viaduct must provide adequate clearance to Lok Ma Chau Boundary Crossing, and the Eastern Main Drainage Channel pump house.
Gradient limitation	Tunneling beneath existing East Rail and River Sutlej is limited by the gradient of descent. Special ground treatment would be required to meet gradient requirements.	Cutting is required at Pak Shek Au to maintain consistent vertical alignment.	Where viaduct is required, the length is dictated by the gradient, before the rail can change to at grade or tunnel.
Safety issues	Tunneling requires ventilation and emergency accesses.	Safety access can be readily achieved.	Safety access can be relatively easily achieved.

2.9.6.3 Tables 2.4 and 2.5 illustrate that both the viaduct option and the tunnel option would entail less environmental impact than the at-grade option. However, the judgement from the Appeal for the viaduct option (described earlier in this chapter) required further study of the relationship between farming activities and wetland ecological habitats before the feasibility and workability of wetland creation in Long Valley could be determined. Given programme constraints and the availability of a workable solution for tunnel construction, the tunnel option was selected for further evaluation.

2.9.6.4 The selection of the tunnel option across Long Valley minimizes the impact of the railway on Long Valley, a fact that greatly increases the attractiveness of this option. The selected Central Alignment minimizes the length of the route across Long Valley, minimizing potential hydrological impacts and also facilitating tunneling operation. Railway operation is also improved by providing the most direct and straight route to the Chau Tau area.

2.9.6.5 The tunnel route is maintained on the selected horizontal alignment across Long Valley, as selected for the above ground option, i.e. the Central Alignment, because this involves least impact to the River Channel works, least disturbance to villages in the vicinity of the tunneling alignment and less impact on existing facilities. The fact that the tunnel is underground already resolves the impacts to the surface of Long Valley. For this reason, no further detailed evaluation of the horizontal options was considered for the selected vertical alignment.

2.9.6.6 The difficulties in constructing a tunnel beneath the existing East Rail, in shallow ground beneath a major river channel and through a wetland floodplain, have been overcome through complex and costly engineering solutions. The works involved will bring into play new environmental issues to be addressed in the current EIA report. In particular, the works carried out to relocate East Rail will involve construction works close to residential buildings. Concerns raised over potential hydrological impacts on Long Valley from the tunnel construction and operation have been addressed through use of a highly sophisticated Earth Pressure Balance Tunnel Boring Machine in the construction stage, and groundwater modelling to demonstrate minimal impacts in the operation phase. Consultations with relevant stakeholders have taken place at an early stage in the current EIA process, to explain the works being carried out to minimise potential impacts on ecologically sensitive areas.

2.9.6.7 The tunnel will continue to Chau Tau from where the railway will rise gradually onto the original viaduct alignment before reaching Lok Ma Chau station. Lok Ma Chau station and immigration facilities must be above ground before passengers pass across to Shenzhen by footbridge.

2.9.6.8 The relative location of the launching shaft and recovery shaft was determined on the basis of land and environmental constraints. The choice of Sheung Shui or Chau Tau ( the location of the future Railway Storage Yard) for the launching shaft location was determined based on the early availability of land and potential environmental impacts to a bat colony in the Chau Tau area. To minimize disturbance to this ecological resource, the launching shaft was located at Sheung Shui, and the smaller recovery shaft at Chau Tau.

2.10 Description of Scenarios with or without the Project

2.10.1 The primary aim of the Spur Line is to relieve the increasing number of passengers at Lo Wu, which has been detailed in Section 1. In the event that the Spur Line Project could not be constructed, it would mean the congestion problem at Lo Wu Station could not be resolved. This would pose a serious safety concern to the existing cross boundary service provided by the East Rail, especially in light of the increasing cross boundary journeys. During the year 2000 Easter period, a new record was set at 335,000 crossings during a single day.

2.10.2 Railway transportation has been widely recognized as the most environmental friendly and efficient means of public transportation. Under the latest Government developmental programmes, railway transportation will become the backbone of some future “Green Towns”. According to the current NENT Study, the Spur Line will be vital to satisfy the future transportation needs of the future Kwu Tung North NDA in an environmentally sustainable manner. Without the Project, the transportation needs of the NDA could not be met in an environmentally sustainable manner.

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