2 PROJECT DESCRIPTION

2.1 Development of Cruise Terminal and Site Constraints

General

2.1.1 Development of the cruise terminal at Kai Tak would require dredging at the existing seawall at the southern tip of the former Kai Tak Airport runway for construction of a berth structure and transition structures, and dredging the seabed fronting the new berth structure to provide necessary manoeuvring basin. The general layout of the proposed cruise terminal is shown in Figure 2.1.

Phasing of Development

2.1.2 It is planned to implement the cruise terminal in two phases. Phase I Berth (the southern portion) of 400m long for the initial phase is scheduled for operation by 2012. The general layout for the initial phase is shown in Figure 2.2. For the initial phase, the 400m berth also requires a 50m buffer at the northern end of the edge structure without affecting the operations at the Phase I Berth.

2.1.3 Phase II Berth (additional 400m at the northern portion) for the longer term is currently scheduled for operation after 2015. The actual commissioning program of the Phase II Berth would depend on the future demand for the cruise terminal. The general layout for the longer term is shown in Figure 2.3. In the longer term a transition structure is required at the northern end of the Phase II Berth to allow for a transition to the existing seawall. The transition structure for the Phase II Berth (Figure 2.3) is 50m long.

Staged Dredging Requirements

2.1.4 Dredging will be required in the Harbour, in the area around the former Kai Tak Airport runway for construction of the cruise terminal. Three dredging zones, namely Zone A, Zone B and Zone C as delineated for cruise terminal construction are shown in Figure 2.4a.

2.1.5 There is a pair of 400 mm diameter submarine gas pipelines currently located to the west of the former Kai Tak Airport runway within the required manoeuvring space and the dredging zone of the Phase II Berth (i.e. within Zone C). The available water depth over the submarine gas pipeline is not adequate for safe manoeuvring of cruise vessels. The pipelines serve as a strategic gas supply to Hong Kong Island and is covered under an existing wayleave agreement. Hence, the pipelines would need to be reprovisioned before dredging can commence for the Phase II Berth.

2.1.6 In view of the constraint of the existing gas pipelines, the dredging works have to be implemented in two stages to cover the three dredging zones, in the areas as indicated in Figure 2.4. Dredging in Zone A required for operation of the Phase I Berth is currently assumed to be carried out during the period from later half of 2008 to 2011 as part of the Stage 1 dredging. For dredging in Zone B, it is to tie in with the Phase II Berth construction and is to complete in 2013. The EIA for Stage 1 dredging has assessed the cumulative impacts from all known possible activities anticipated in the period from 2008 to 2011 which should represent the worst-case scenario during the Stage 1 dredging period. Dredging for the Phase II Berth within Zone C (Stage 2 dredging) would need to be carried out at a later stage after decommissioning of the existing submarine gas pipelines in 2013. The programme for Stage 2 dredging within Zone C is unconfirmed at this stage but its completion can be extended up to 2020 and the earliest possible time for the Stage 2 dredging would be 2013 to 2014 after the Stage 1 dredging and decommissioning and removal of the existing submarine gas pipelines. The current tentative target programme is to commence the Stage 2 dredging works in 2013 for completion in 2014 for the purpose of this EIA only. The actual programme might be deferred due to the progress of the reprovisioning of the submarine gas pipelines and the need for additional berths as driven by the cruise market. Based on the currently available information, the assessment for Stage 2 capital dredging has assumed all other marine works (except for maintenance dredging for the Phase I Berth) anticipated in or beyond 2012 up to 2020 that would occur concurrently in the assessment year of 2013/2014. Maintenance dredging for the Phase I Berth will not be conducted concurrently with the Stage 2 capital dredging. In other words, the assessment has covered the impacts arising from the Stage 2 capital dredging to be carried out anytime between 2012 and 2020.

Government Mooring Buoys

2.1.7 The existing Government Mooring Buoys (GMB) A17 and A43 (Figure 2.4) covering an area of around 440m diameter are positioned south of the Phase I Berth in the area earmarked for the vessel turning basin. These “A” buoys will need to be removed and repositioned clear of the turning basin prior to commencement of operations at the Phase I Berth. Provision has been made for these “A” buoys to be relocated further east adjacent to the edges of the Eastern Fairway and Eastern Harbour Crossing reserve.

2.1.8 In the long term, the reconfiguration of the Eastern Quarantine and Immigration Anchorage (EQIA) and reprovisioning of the submarine gas pipelines will be required. Whether the existing 5 GMBs in Kowloon Bay would need to be relocated, would be subject to The Hong Kong and China Gas Company Limited (HKCGCL) gas pipelines realignment proposal.

2.1.9 Based on the current design it has been confirmed that the current water depth at the proposed relocated GMBs is sufficient without the need for dredging. It should be noted that the method of securing the GMBs is to place a large concrete block on the seabed. When the existing GMBs are removed, there will not be any disturbance to the seabed other than to any silt that may have accumulated on top of the anchor block since its installation. In this respect the likely volume of disturbed material is only likely to be in the order of 10 m³ at most. As such there would not be any adverse impacts on water quality when relocating the GMBs.

Eastern Quarantine and Immigration Anchorage

2.1.10 The EQIA is adjacent and west of the Phase I Berth with a minimum clear separation from eastern tip (PHE buoy) and berth copeline of 250m. To allow for the vessel manoeuvring for the Phase II Berth of the cruise terminal, minor reconfiguration of the EQIA is required (Figure 2.4). The EQIA reconfiguration is currently scheduled to be carried out before operations commence at the Phase I Berth. The method for removal and reinstatement of the PHE buoy would be the same to that for relocating the GMBs as described in the above paragraph. No dredging is required and no adverse cumulative water quality impact is expected from the EQIA reconfiguration.

Kai Tak Runway Submarine Outfall

2.1.11 There is an abandoned submarine outfall namely KTR outfall (1800mm diameter) at the tip of the former Kai Tak Airport runway which runs through and emerging towards the Eastern Fairway within the proposed Stage 1 dredging area for cruise terminal in Zone A (Figures 2.4 and 2.4a).

2.1.12 As shown in the as-built drawings in Appendix 2.1a, it can be seen that the sewerage outfall served the former Kowloon East Screening Plant which has now been decommissioned and therefore not considered as part of the former Kai Tak Airport operation.

2.1.13 This abandoned KTR outfall will need to be removed in order to allow the dredging of existing seabed to the required level for cruise terminal construction. Removal of the KTR outfall would involve dredging of the seabed. It is proposed to remove all sections of the outfall where the crown of the outfall lies above a level of -13mCD. It is estimated that 200m of the 710m long outfall pipe would need to be completely removed and the pell mell rubble protection would need to be removed for a further 200m in order to allow future dredging in the vessel manoeuvring basin for the cruise terminal. The extent of submarine outfall dredging is shown in Figure 2.4b. It is estimated that the total volume of dredged material generated from the outfall removal works would be in the order of 20,000 m³.

2.1.14 It is proposed that the sections of submarine outfall and the sections of pipe buried beneath the former runway are to be removed as part of the Stage 1 dredging works for cruise terminal construction.

2.2 The Need of Project and Scenario without the Project

2.2.1 The proposed dredging works are essential to provide necessary manoeuvring basin for development of the cruise terminal. The depth alongside the berth face of the cruise terminal has been determined to suit the maximum draft of design vessel, plus 10% under keel clearance and 0.5m allowance for siltation. Based on a draft of 10m for the Queen Mary II gives:

· Lowest Astronomical Tide (LAT), 0.0mCD

· greater draft of the vessel currently in operation (Queen Mary II), 10m

· allow 10% of the maximum draft for gross underkeel clearance according to BS 6349-1:2000 ie. 1m

· allow 0.5m siltation

2.2.2 Accordingly, the minimum seabed level should be 0mCD – (10m + 1m + 0.5m) = -11.5mCD, i.e. -12mCD. Given that the existing seabed levels in the vicinity of the cruise terminal as shown in Figure 2.5 is higher than the required minimum level of -12mCD, the proposed dredging is essential for construction and operation of the proposed cruise terminal at Kai Tak to provide space needed for safe manoeuvring of cruise vessels clear of the fairway and cruise berth. Without the proposed dredging works, the safety of the cruise vessels’ manoeuvring will be in question.

2.3 Project Benefits

2.3.1 The Government aims to develop Hong Kong into a leading regional cruise hub through the development of a world-class cruise terminal with state-of-the-art facilities which are user-friendly, and provide efficient and quality services. The facilities and services provided by the New Cruise Terminal should have built-in flexibility to allow for adjustments to meet the need of different types of cruise vessels and different cruise market segments. They form part of an overall experience of a cruise passenger and add value to a cruise vacation. In October 2006, the Government announced its plan to proceed with the development of a New Cruise Terminal on a site of 7.6 hectares at the southern end of the former runway in the Kai Tak Development.

2.3.2 One of the key considerations for locating the New Cruise Terminal at Kai Tak is that it is the only site within the Victoria Harbour with the capability to provide two or more berths without reclamation. The proposed location for the New Cruise Terminal at the southern end of the runway has a deep seabed and large manoeuvring space along the former runway for receiving mega cruise vessels. Besides, public consultations on the Kai Tak Planning Review (KTPR) concluded that there was general support in the community for the early implementation of the New Cruise Terminal in the Kai Tak Development.

2.3.3 Upon completion of the New Cruise Terminal, together with the existing cruise terminal in Tsim Sha Tsui, Hong Kong will have four berths in total for cruise vessels. This will better serve the needs of the cruise industry and help sustain Hong Kong’s development as a regional cruise hub.

2.4 Project Requirements

General

2.4.1 A two-berth cruise terminal is proposed at the southern tip of the former Kai Tak Airport runway. The scale and extent of the dredging works for cruise terminal construction would depend on the size of the cruise berth structure and the navigation depths and space needed for safe manoeuvring of cruise vessels.

2.4.2 The cruise terminal development will need to cater for a range of cruise vessels applicable to the region or expected to operate in the future. The size, sophistication and capacity of cruise vessels will dictate capital and maintenance dredging (navigation depths, size of manoeuvring areas), the length and capacity of the cruise terminal berth structure as well as terminal facilities and supporting infrastructure, particularly transport facilities.

Manoeuvring Area

2.4.3 The provision of turning basin of 650m in diameter is recommended allowing for about 2 times the overall length of the cruise vessel Norway of 315m (commissioned in 1981). Manoeuvrability of cruise vessels will vary according to their size, class and vintage. The latest generation of cruise vessels in operation are relatively longer (currently up to 345m) but can be expected to be relatively more manoeuvrable compared to older vessels. The 650m diameter turning basin has been confirmed by detailed vessel simulations, to be adequate for the latest generation of cruise vessels.

2.4.4 The 650m diameter turning basin positioned just south of the Phase I Berth and immediately adjacent to both the Eastern Fairway boundary and the 100m wide reserve centred about the submarine gas pipeline alignment (Figure 2.4).

2.4.5 Manoeuvring space is required adjacent to the Phase II Berth with an area approximately 288m wide relative to the copeline (Figure 2.4). This clearance equates to a minimum of 230m net clearance from the vessel moored at the Phase I Berth.

Dredging

2.4.6 For overall cost effectiveness, initial navigation dredging for operation of Phases I and II should allow for dredging to -12mCD as justified above in Section 2.2. The area alongside of the berth structure is to be dredged to provide a depth alongside of -13mCD to allow for possible future deepening of the manoeuvring area if future new vessels entail such water depth. The staged dredging requirements for the cruise terminal are shown in Figure 2.4.

2.4.7 The existing seabed levels within the Study area (based on IGGE geophysical survey report under CEDD Contract GE/2005/26) are shown in Figure 2.5. The total in-situ volume of dredging required for the vessel approach and manoeuvring area to the Phase I Berth is estimated to be about 700,000m³. Additional in-situ volume of dredging required for the Phase II Berth for vessel manoeuvring areas is estimated to be about 680,000m³.

2.4.8 In addition, removal of the existing seawall by dredging is assumed to be required for berth construction at the south western edge of the former Kai Tai Airport runway. The volume of existing seawall to be removed by dredging is approximately 322,300 m³ (see Table 2.1 and Table 2.2) and this volume is additional to the material to be dredged for the manoeuvring area as mentioned in Section 2.4.7 above.

2.5 Project Scope and Programme

2.5.1 The scope of the Project comprises:

l Dredging of marine sediment of about 1.38M m³ from the existing seabed in the Harbour area off the southern tip of the former Kai Tak Airport runway to provide the necessary water depth within the manoeuvring area for cruise vessels; and

l Removal of existing seawall of about 322,300 m³ by dredging at the southern tip of the former Kai Tak Airport runway for cruise berth construction.

2.5.2 The dredging programme is shown in Appendix 2.1. Breakdown of the dredging volumes is given in Table 2.1. Estimated volumes of contaminated sediments are given under Section 6 of this report on Waste Management Implications.

^{Table 2.1 Volume
of Dredging}

Stages (Figure 2.4)	Volume of Dredging (m³)
	From Existing Seabed in the Harbour Area	From Existing Seawall			Total
	From Existing Seabed in the Harbour Area	850 m Berth Structure	Transitional Structures	Total	Total
Stage 1 Dredging Total:	700,000 ⁽¹⁾	258,500	63,800	322,300	1,022,300
Stage 2 Dredging Total:	680,000	-	-	-	680,000
Total (Stage 1 + Stage 2):	1,380,000	258,500	63,800	322,300	1,702,300

Note 1: The total volume of 700,000 m³ includes the dredged material of 20,000 m³ to be generated from removal of the abandoned KTR outfall (refer to Section 2.1.13 and Figure 2.4b).

2.5.3 The dredging volume presented in this EIA are the result of a detailed engineering assessment. The total dredging volume is estimated to be about 1.7M m³ as shown in Table 2.1. Quantities have been reviewed against all available bathymetric and testing data available to date. They are the best estimate for this EIA.

2.5.4 Dredging required for operation of the Phase I Berth is currently assumed to be carried out during the period from 2009 to 2011 as the first stage. However, the earliest possible time for commencing the Stage 1 dredging could be in the later half of 2008. The EIA for Stage 1 dredging has considered the cumulative impacts from all concurrent activities anticipated in the period from 2008 to 2011 to allow the possible change of the Stage 1 dredging programme to commence in 2008. As the programme for Stage 2 dredging is unconfirmed, for the purpose of this EIA, it is assumed that the Stage 2 dredging would be carried out from 2013 to 2014, following the Stage 1 dredging and decommissioning and removal of the existing submarine gas pipelines. The period of 2013 - 2014 is selected as the time horizon for Stage 2 dredging for impact assessment only. The selected time horizon is the earliest possible timing for Stage 2 dredging. Based on the currently available information, the assessment for Stage 2 capital dredging has assumed all other marine works (except for maintenance dredging for the Phase I Berth) anticipated in or beyond 2012 up to 2020 that would occur concurrently in the assessment year of 2013/2014. Maintenance dredging for the Phase I Berth will not be conducted concurrently with the Stage 2 capital dredging. In other words, the assessment has covered the impacts arising from the Stage 2 capital dredging to be carried out anytime between 2012 and 2020.

2.5.5 This EIA has not addressed the environmental implication of the third berth which is outside the scope of this EIA. Any possible third berth development in future should be subject to separate study.

2.6 Consideration of Alternatives and Development of Preferred Option

Site Location

2.6.1 According to the studies conducted by the Tourism Commission, taking into account different growth scenarios, Hong Kong will require an additional cruise terminal berth between 2009 and 2015, and one to two further berths beyond 2015 to sustain its development as a regional cruise hub. The two-alongside berths configuration in the draft Preliminary Outline Development Plan (PODP), which was prepared on the basis of “no reclamation”, represents the best compromise in resolving identified technical difficulties, meeting the needs of cruise market and avoiding the sterilization of a long stretch of the waterfront. The PODP has provided for the development of two berths. Some flexibility has also been built into the PODP to allow flexibility for possible future development of a third berth. To achieve this, land uses compatible with cruise terminal development, e.g. conference and hotel facilities, have been designated on the sites adjacent to the potential berthing space in the runway area and the disposal of these sites has been timed for a later phase. As such the town plan and land disposal programme could be amended where necessary to meet the need for a third cruise berth at Kai Tak in the future.

2.6.2 Adequate water depth, turning basin and landside developable space are the three key requirements in determining the location of cruise terminal. The proposed location at the runway tip would be best able to meet the above requirements when compared to the rest of Kai Tak. The PODP has proposed two-alongside berths configuration comprising a continuous 850 m long berth structure to cater for simultaneous berthing of one 360m and one 345m long cruise vessel. This is expected to be able to accommodate the longest cruise vessel commissioned to date. The proposed location for the cruise terminal at the runway tip has the deepest seabed along the former runway and larger manoeuvring space for receiving mega cruise vessels. The access from and to the main fairway is also a very direct one. Relocating the cruise terminal to the middle part of the former runway will affect the operation of the existing typhoon shelter, mooring buoys and submarine gas pipelines, which in turn would affect the implementation programme of the cruise terminal. Besides, more extensive seabed dredging would be required as the water depth there is much more shallower (about 2-6m). This will not only increase the technical difficulties but will also bring about more severe environmental implications.

2.6.3 An alternative location for the cruise terminal at West Kowloon has been considered. The West Kowloon proposal is considered inappropriate in view of the water depth of the foreshore area for manoeuvring and/or berthing of mega cruise ships. The impact on the existing marine facilities and more importantly, the surrounding road network, public transport system and supporting facilities is considered unacceptable and as such this proposal was not supported.

Dredging Extent

2.6.4 Dredging will be carried out in the Harbour area and around the former Kai Tak Airport runway. The proposed size and configuration of the manoeuvring areas discussed in Section 2.4 of this report was reviewed using real time vessel simulations. The real time vessel simulations were carried out by an experienced independent Master Mariner using PC Rembrandt. The simulations were used to confirm the required navigation space for such operations including the approach, turning and berthing of the cruise ships. In so doing the simulation works have confirmed the required dredging and associated reprovisioning of existing marine facilities affected within Kowloon Bay. The following is a summary of the results of the analysis for the vessel simulation scenarios in relation to the determination of vessel manoeuvring area:

(a) The real time vessel simulation results indicate that a smaller dredged area than the manoeuvring areas described in Section 2.4 of this report would not be acceptable, even if operational restrictions were placed on the access of vessels in the worst conditions, or the use of tugs was mandated.

(b) Extreme strong ebb tide pushes the vessels onto the berth, especially at the south end. The manoeuvring area to the south of the runway is therefore required to be dredged in line with the berth cope line.

(c) The entrance from the fairway into the turning area caused problems during departing and arriving. The assessment determined that it would be necessary to provide a wider fairway entrance that ran to the present fairway buoy at the southeast tip of the EQIA.

(d) Stage 1 manoeuvring area is adequate for cruise ships to manoeuvre to/from the Phase I Berth without requiring the relocation of the existing submarine gas pipelines.

(e) The manoeuvring area adjacent to the Phase II Berth has a width of 288m and the access to the Phase II Berth is partially constrained when a vessel is alongside the Phase I Berth. Even with the largest vessel on the Phase I Berth the simulations showed that the available space is adequate for all manoeuvres to and from the Phase II Berth.

2.6.1 The dredging works will be carried out in two stages as shown in Table 2.1 and Figure 2.4. The proposed dredging extent is essential to provide space needed for safe manoeuvring of cruise vessels clear of the fairway and cruise berth.

Dredging Programme

2.6.2 The programme for Stage 1 dredging is governed by the required commissioning date of the Phase I Berth. Thus, dredging required for operation of the Phase I Berth (Zone A) has to be carried out during the period from later half of 2008 to 2011 as the first stage in order to meet the commissioning programme for the Phase 1 Berth. Due to the site constraints as discussed in Section 2.1, dredging for the Phase II Berth (Zone C) would need to be carried out at a later stage after decommissioning and removal of the existing submarine gas pipelines. The actual program for Stage 2 dredging would also depend on the future demand for the cruise terminal. The current tentative programme is to commence the Stage 2 dredging in 2013 for the purpose of worst-case impact assessment (refer to Section 2.5.4). Therefore, no alternative programme has been considered for the capital dredging. Based on the water quality model predictions provided in Section 5 of this EIA report, no unacceptable water quality impacts are expected under the assumed programme for Stage 1 and 2 capital dredging (i.e., from later half of 2008 to 2011 and 2013 to 2020 respectively) with implementation of all the recommended mitigation measures.

2.6.3 The duration of maintenance dredging would be less than 6 months for each phase. Alternative programme for the maintenance dredging to be carried out in either dry or wet seasons has been considered under the water quality impact assessment in Section 5. Based on the model predictions, maintenance dredging in wet season would contribute larger water quality impact and is therefore not preferred. It is recommended in this EIA that the maintenance dredging should not be programmed in wet seasons (April to September) to avoid the potential water quality impacts.

Dredging Method, Dredging Rates and Staged Dredging Requirements

2.6.4 Dredging in the Harbour area required for safe manoeuvring of cruise vessels would be carried out at a maximum production rate of 4,000 m³ per day during both the Stage 1 and Stage 2 period. The total volume to be dredged is estimated as 700,000 m³ for Stage 1 and 680,000m³ for Stage 2. The total volume of 700,000 m³ for Stage 1 dredging includes the dredged material of 20,000 m³ to be generated from removal of the abandoned KTR outfall (refer to Section 2.1.13 and Figure 2.4b). At a maximum rate of 4,000 m³/day, it would take 175 days to dredge the Phase I Berth and 170 days to dredge the Phase II Berth. The current programme allows 12 months and 10 months for dredging for the Phase I Berth and the Phase II Berth respectively and dredging is not on the critical path.

2.6.5 Closed grab dredgers are considered as the most suitable dredgers for relatively small volumes and contaminated mud. It is feasible to use small trailer suction dredgers although these will give less control over handling of contaminated mud and produce more marine sediment by volume (due to high water content) when compared with grab dredging. Whilst larger equipment has been adopted for major reclamation projects such as the Penny’s Bay reclamation and Container Terminals in Kwai Chung, in this case, given that dredging is not on the critical programme path, it is assumed that the most cost effective construction method with the least environmental impact will be adopted for the cruise terminal i.e. closed grab dredgers.

2.6.6 The dredging rate of 4,000 m³ per day for Stage 1 and Stage 2 assumes that the area will only be big enough to sustain 2 grab dredgers operating simultaneously. Barges serving each grab dredger are assumed to have a capacity of 1,000m³ and can complete up to two trips to the marine dumping area per day.

2.6.7 In addition, removal of the existing seawall by dredging will be required for berth construction at the south western edge of the former Kai Tai Airport runway. The volume of existing seawall to be removed by dredging is approximately 322,300 m³ (see Table 2.1 and Table 2.2). Dredging from the existing seawall for berth construction would be carried out concurrently with the Stage 1 dredging at a maximum production rate of 4,000m³ per day by 2 grab dredgers.

2.6.8 The water quality modelling assessment has included the assumption that there may be a number of concurrent dredging projects nearby to the cruise terminal. These assumptions are conservative in order to allow all potential projects to proceed without severe constraints. The dredging locations, rates, timing and phased implementation have been analyzed and confirmed by the technical assessments performed under this EIA to be environmentally acceptable. In particular, modelling assessment has been carried out under this EIA to assess the water quality impacts of undertaking the dredging in either the dry or wet season and concluded that the proposed dredging rates, locations and timing would not cause any unacceptable water quality and marine ecological impact, provided that all the mitigation measures recommended under this EIA are properly implemented. Further consideration of alternative dredging rate is not necessary.

Berth Structure

2.6.9 A section of the existing seawall at the former Kai Tak Airport runway will need to be re-constructed for the cruise terminal berth structure. Seawall reconstruction would involve dredging of the existing seawall of the runway. The berth structure would be constructed within the land limits as a measure to protect and preserve the Harbour. The type of berth structure would affect the extent of dredging required for seawall reconstruction at the former Kai Tak Airport runway. Preliminary schemes for six types of berth structure have been developed and reviewed. These options cover a range of structural schemes which have been used to various degrees internationally and include the following:

l Option 1 – Piled Quay Deck;

l Option 2 – Precast Reinforced Concrete Caisson;

l Option 3 – Precast Concrete Blockwork Seawall;

l Option 4 – Bored Pile Retaining Wall with Anchor;

l Option 5 – Precast Reinforced Concrete Counterfort Wall; and

l Option 6 – Sheet Pile Cofferdam Wall

2.6.10 Based on the above berth structure options, a qualitative assessment has been conducted by comparison on environmental benefits and dis-benefits, cost, programme, engineering and maintenance requirements. The general arrangement of the six types of berth structures is shown in Figure 2.6 to Figure 2.11 respectively.

Option 1 - Piled Quay Deck

2.6.11 The open piled quay structure would require relatively less amount of dredging at the existing seawall as compared to other options (except Option 4). The general arrangement of this option is shown in Figure 2.6. The piled quay with underlying sloping seawall revetment would more effectively absorb wave energy with beneficial effects on vessel operations alongside adjacent berths. The piled structure provides a conventional, reliable and robust structure on which the cruise terminal operations can be supported and can be adapted to cater for a wide array of bunkering facilities that may be required.

2.6.12 For this option, the piled quay structure can be supported by either bored cast in-situ reinforced concrete (RC) piles or driven steel tubular piles. The bored cast in-situ RC pile system consumes a relatively large amount of permanent steel casing and in-situ reinforced concrete, i.e. a higher capital cost. Accordingly, the driven steel tubular pile with reinforced concrete infill system is more commonly adopted in Hong Kong.

2.6.13 Potential deterioration of the quay deck from corrosion of the steel reinforcement especially within the tidal and splash zone with potentially rapid deterioration in any areas of defective workmanship. In order to prolong the service life of the pile structure in such circumstances cathodic protection may need to be implemented.

Option 2 – Precast Reinforced Concrete Caisson

2.6.14 The precast reinforced concrete (RC) structures (Figure 2.7) are typically more durable under severe marine environmental conditions than in-situ reinforced concrete structures. The RC caisson can achieve fast construction placement rates since the units can be fabricated in advance, then transported to site and sunk in place in a relatively short period.

2.6.15 However, this option would require more dredging as compared to the pile option. In addition, the lead time for the precasting works may result in an initial delay of the works. Significant time may be required to locate a suitable casting yard location with practical draft depth for the proposed caisson units. Transportation of the caisson from a remote casting area to the site would be subject to either shipping restrictions through the navigation channel and weather conditions. There would be considerable uncertainty regarding the caisson costs because of the requirements for special off site dry docks or similar provisions for casting and launching the units and transportation.

Option 3 – Precast Concrete Blockwork Seawall

2.6.16 The fabrication of precast units is one means of speeding up construction since the units are prefabricated and placed in quick succession following the seawall dredging and foundation preparation. The construction method is comparatively simple and versatile which may not require large numbers of skilled labourers. The general arrangement of this option is shown in Figure 2.8.

2.6.17 The mass concrete block structure is more durable under severe marine and environmental conditions than reinforced concrete structures or steel structures. Maintenance costs for blockwork walls are therefore expected to be relative low compared to other options.

2.6.18 However, this option would require more extensive dredging as compared to the pile option. Moreover, the weight of the concrete blockwork are relatively heavy, up to approximately 150 tonnes, which is likely to make it time consuming and expensive to procure, mobilize and operate suitable heavy lift construction plant. Any settlement of the foundation could cause the blockwork wall tilt forwards or backwards. The efficiency and cost of the blockwork system depends in part on the availability of a suitable casting yard which needs to be easily accessed by floating plant for delivery of the blocks to site. It is expected however that space would be made available on site for such a casting yard.

Option 4 – Bored Pile Retaining Wall with Anchor

2.6.19 This scheme involves a series of bored piles (Figure 2.9) constructed consecutively to form a wall to retain the backfill with a continuous reinforced concrete coping beam to interconnect the tops of the bored piles. High strength tie rods are connected near the top of the pile wall at regular intervals and extend back to an anchor wall on the land side to provide additional support.

2.6.20 Under this system, the bored pile wall acts as a propped cantilever structure with the base fixed in rock and the lateral loads such as earth pressure, tidal forces, berthing force and mooring force resisted in bending of the piles. The anchor system aims to provide additional support to the bored pile wall and reduce the wall deflection.

2.6.21 The bored pile retaining wall with anchor would require the least extent of dredging and would be the most preferred option based on environmental consideration. The system can be utilized to minimize excavation and disposal of existing runway material.

2.6.22 Bored pile construction is widely adopted in Hong Kong and skilled labour for construction can be found locally. The residual long term settlement of the retaining wall would be expected to be minimal with most settlement arising during the construction period provided lateral wall movements are controlled.

2.6.23 However, the bored pile retaining wall will not attenuate wave agitation and is unfavourable for the berthing operation. The bored pile wall option would not satisfy the general guideline of ETWB Technical Circular 3/95 about wave reflection control at Victoria Harbour. Moreover, potential corrosion of tie rods will affect the structural integrity of the cantilevered bored pile wall. Cost should also be a major concern for this option because significant piling is required to provide the tie rod anchoring system. In this connection, this option is not recommended to consider further.

Option 5 – Precast Reinforced Concrete Counterfort Wall

2.6.24 The reinforced concrete (RC) counterfort wall option (Figure 2.10) can achieve a fast construction rates provided marine access is not a limiting factor. High standards of workmanship are also possible because the units can be fabricated at a casting yard on land then transported to the construction site. The counterfort wall system is typically a relatively economic structural system provided that casting yard and heavy lift equipment are available.

2.6.25 However, this option would require relatively more amount of dredging at the seawall and thus not an environmental preferred option. The establishment costs for the preparation of a floating dock or casting yard with suitable water front access could also be high. In addition the mobilisation cost of heavy lifting equipment and floating crane, etc are comparatively high. Since each counterfort wall unit may weigh more than 200 tonnes, it is likely that significant additional costs will arise in securing and utilizing suitable plant / machinery to handle the units from the market. A wave absorption chamber cannot be easily incorporated at the front of the counterfont wall hence this structural system would not comply with ETWB Technical Circular 3/95 in relation to wave reflection control at Victoria Harbour.

2.6.26 In view of the above environmental and engineering disadvantages of the Precast RC Counterfort Wall option, in particular the extreme difficulties in lifting of precast units, it is not recommended to consider this option further.

Option 6 – Sheet Pile Cofferdam Wall

2.6.27 The construction method for the sheet pile cofferdam wall (Figure 2.11) is comparatively simple and versatile which may not require large numbers of trained / skilled labourers for the construction works.

2.6.28 However, potentially significant corrosion of the sheet pile sections would be a major disadvantage and the sheet piles may therefore need the added cost of cathodic protection. Moreover, the sheet piled cofferdam option would not satisfy the general guideline of ETWB Technical Circular 3/95 about wave reflection control at Victoria Harbour. This option would also require more dredging at the existing seawall as compared to the piled quay deck option and the bored pile retaining wall.

2.6.29 In view of the disadvantages, in particular the corrosion and wave reflection problems it is not recommended to consider this option further.

Summary

2.6.30 Based on the review above, Options 4, 5 and 6 are not recommended based on engineering considerations. All of these three options would not comply with ETWB Technical Circular 3/95 on wave reflection control at Victoria Harbour.

2.6.31 Amongst the three feasible options namely Options 1, 2 and 3, the piled quay deck (Option 1) would require the least amount of dredging at the existing seawall during construction. .

2.6.32 In environmental terms the main difference between Options 1, 2, and 3 is the volume of dredging from the existing seawall for the 850m berth as summarised in Table 2.2 below. The cross-sectional extent of dredging from the existing seawall for Options 1, 2, and 3 is shown in Figures 2.6, 2.7, and 2.8 respectively. It should be noted that the volume of dredging from the existing seawall is comparatively less in the case of Option 1, therefore the allowance for Options 2 and 3 in this EIA represents a worst case assumption.

^{Table 2.2 Approximate
Volume of Dredging from the Existing Seawall}

	Option 1	Option 2	Option 3
Rock armour	54,000 m³	54,000 m³	54,000 m³
General rockfill	144,400 m³	144,400 m³	144,400 m³
General fill/ sand	52,600 m³	52,600 m³	52,600 m³
Alluvium	-	71,300 m³	71,300 m³
Total Approximate Volume of Dredging	251,000 m³	322,300 m³	322,300 m³

Notes:

All the material to be dredged from the existing seawall is expected to be uncontaminated C&D material.

Shaded cell – value assumed in this EIA for conservative assessment.

2.7 Siltation and Maintenance Dredging

2.7.1 No survey records have been located to suggest long term siltation rates. However the rate of siltation has been estimated by comparing sea bed levels adjacent to the Kai Tak runway in the years 1993 and 2004 based on information on Navigation Charts. Generally, the average rise of sea bed of 0.5m is noted and the maximum rise of sea bed is approximately 0.7m within the 11 year period. The average siltation rates within the navigation area are therefore expected to be in the range of 50mm to 60mm per year. Siltation rates which may vary significantly across the manoeuvring area. Periodic bathymetric surveys will be required to verify actual siltation rates to prevent siltation raising seabed levels higher than the required navigation level of -12mCD by 0.5m .

2.7.2 The new manoeuvring basin may reduce the water currents and enhance the sediment deposition at the basin. In addition, opening a large gap (600 m) at the runway (to the north of Taxiway Bridge) is being considered as a measure to improve the flushing capacity in Kai Tak Approach Channel (KTAC), which would also alter the local hydrodynamic and sediment transport regime.

2.7.3 A water quality modelling exercise has been conducted using the modelling tools as described under the water quality impact assessment in Section 5 of this EIA report. The aim of the modelling exercise was to provide an indication on the relative change in sedimentation pattern as a result of the new vessel manoeuvring area and the 600 m opening at the runway. Based on the model results, the relative change in current speeds is most significant in the near shore region close to the runway and less significant in the offshore region where the baseline current speeds are higher. In general, higher sedimentation rates are found in the shallow water region near the runway. There is also the observation that the 600 m opening would generally increase the sedimentation rates in the manoeuvring area due to the additional sediment loading discharged from the KTAC.

2.7.4 The contour plot showing the relative increase in the sedimentation rate due to the new bathymetry together with the runway opening is given in Figure 2.11a. The contours shown in the figure represent the % increase of the sedimentation rate as compared to the existing baseline condition which is the averaged value predicted over the model simulation period. The predicted increases of sedimentation in the manoeuvring basin ranged from 0% to 65%. The maximum increase of 65% is predicted at the most inshore corner of the manoeuvring basin only. The average increase in the sedimentation is generally much lower with less than 10% in the offshore region.

2.7.5 As mentioned before, the average siltation rates within the navigation area under the existing condition are expected to be in the range of 50mm to 60mm per year based on the review of Navigation Charts. From the modelling results, the 600 m opening could cause an increase in sedimentation of 0% to 65%. By applying this relative increase of 0 % to 65%, the average siltation rates in the navigation area are expected to be in the order of 50 mm to 100 mm per year.

Sediment Quality

2.7.6 The sediment quality of the proposed manoeuvring area has been under the influences of various water pollution sources in the Victoria Harbour. Before commissioning of the Harbour Area Treatment Scheme (HATS) Stage 1 in 2001, screened (or untreated) sewage generated from the dense urban areas on both sides of the Victoria Harbour is discharged into the sea via the submarine outfalls of local preliminary treatment works (PTW). Since the HATS Stage 1 implementation in 2001, the submarine outfalls of some local PTW (in Kowloon, Kwai Chung, Tsing Yi, Tseung Kwan O and eastern Hong Kong Island catchments) have been decommissioned and the sewage generated from these catchments is intercepted to the Stonecutters Island Sewage Treatment Works (SCISTW) for treatment. After the decommissioning of these local PTW outfalls, the Harbour water quality has been significantly improved but is still affected by the sewage discharges from the Hong Kong Island including the submarine outfalls of North Point PTW (close to the proposed manoeuvring area), Wan Chai East PTW, Wan Chai West PTW and Central PTW. Another key pollution source that has been affecting the sediment quality in the Victoria Harbour would be the pollution discharges at various storm outfalls along the Harbour waterfront as a result of polluted surface runoff or street washing, expedient connections from trade and residential premises, and integrity problems of aged drainage and sewerage systems in the dense urban catchments.

2.7.7 Stage 2A of HATS is currently scheduled for implementation in 2013. Under the Stage 2A, deep tunnels would be built to bring sewage from the northern and western areas of Hong Kong Island to SCISTW for treatment. Therefore, all the remaining PTW outfalls in Victoria Harbour (including the North Point PTW outfall close to the proposed manoeuvring area) would be decommissioned after 2013. Long term reduction of storm pollution loading would also be expected due to the on-going sewerage improvement and water pollution control measures being implemented by the Government. As a result of the load reduction, the future quality of sediment to be generated from maintenance dredging is expected to be improved from the current condition. However, the proposed 600 m opening at the runway would enable the discharge of pollutants from KTAC to the open harbour, it cannot be ruled out that the future sediment quality in the manoeuvring area could be adversely affected by the polluted water discharged from KTAC. As the reduction of pollution loading due to the HATS implementation would be larger than that discharged from the 600 m opening, there should still be an overall reduction of pollution loading and long term improvement in the sediment quality. In any case, maintenance dredging would require sediment sampling and testing in accordance with the requirements of the ETWB TCW No. 34/2002 for proper disposal of the uncontaminated and contaminated dredged sediment. Marine Fill Committee (MFC) would determine the most appropriate open sea or confined marine disposal site on the basis of the chemical and biological test results and formally allocate marine disposal space in accordance with the ETWB TCW No. 34/2002.

Dredging Rate and Method

2.7.8 It is assumed that the siltation rate will be in the order of 50mm to 100mm per year. As such up to 500mm of sediment will need to be dredged every 5 to 10 years. Given that the area needed for manoeuvring of vessels is approximately 700,000 m², then this represents a dredged volume of approximately 350,000 m³ every 5 to 10 years. This would take one grab dredger approximately 8 months to dredge assuming a production rate of 2,000m³ per day and limited access.

2.8 EIA Study Area

2.8.1 The following definitions of the study areas have been adopted with reference to the EIA Study Brief (No. ESB-159/2006) registered under the EIAO:

l Air Quality Impact: the assessment area should include the area within 500 m from the boundary of the dredging zones (Figure 3.1 and Figure 3.2);

l Noise Impact Assessment: the assessment area should include the area within 300 m from the boundary of dredging zones (Figure 4.1a);

l Water Quality Impact Assessment: the assessment area should include the Victoria Harbour Water Control Zone (WCZ), Eastern Buffer WCZ, Western Buffer WCZ, Junk Bay WCZ and Port Shelter WCZ as declared under the Water Pollution Control Ordinance (see Figure 5.1) or the area likely to be impacted by the Project;

l Waste Management: the assessment will be focused on areas within the boundary of the dredging zones (Figure 2.4a);

l Marine Ecology and Fisheries: the assessment area for marine ecological impact will be the same as that for the water quality impact assessment (see Figure 5.1); and

l Cultural Heritage Impact: the assessment for cultural heritage impact will focus on the area within the boundary the proposed dredging zones (Figure 2.4a).

2.9 Interaction with Other Projects

Land-based Works

2.9.1 Air quality and noise impact assessments have taken into account other concurrent activities within 500 m and 300 m respectively from the boundary of the proposed dredging area for cumulative assessment. Concurrent activities within 500 m from the proposed dredging site would cover possible land-based works at the former Kai Tak Airport runway for construction of the developments proposed under the PODP including the construction of cruise terminal (during Stage 1 dredging only) and associated commercial developments and possible residential developments at the southern part of the runway.

Marine Works

2.9.2 In accordance with the EIA Study Brief (No. ESB-159/2006), the assessment area for water quality and marine ecology should include the Victoria Harbour Water Control Zone (WCZ), Eastern Buffer WCZ, Western Buffer WCZ, Junk Bay WCZ and Port Shelter WCZ.

Kai Tak Development (KTD) Area

2.9.3 Possible concurrent marine works within or near the KTD area include the following:

l Submarine gas pipelines relocation to the west of the former Kai Tak Airport runway;

l Opening a 600m gap at the northern section of the former Kai Tak Airport runway (north of the Taxiway Bridge);

l Construction of piled deck to cover the 600m gap opening of the runway to form part of the Metro Park

l Construction of the proposed public landing steps cum fireboat berth at the former Kai Tak Airport runway to the north of the proposed dredging works for cruise terminal;

l Decommissioning of the disused fuel dolphin in Kowloon Bay;

l Construction of Central Kowloon Route (CKR) near the corner of inner Kowloon Bay; and

l Construction of Road T2 in and adjacent to the Kwun Tong Typhoon Shelter (KTTS).

2.9.4 The programmes for these possible marine works showing potential overlap with the proposed dredging works for cruise terminal is given in Appendix 2.1. The locations of these concurrent marine works are indicated in Figure 2.12.

2.9.5 The submarine gas pipelines diversion programme and the alignment of the new gas pipelines are still subject to confirmation by detailed design. The Hong Kong and China Gas Company Limited (HKCGCL) have indicated two possible alignments for the new gas pipelines crossing namely an east option (1.4km from the tip of the former Kai Tak Airport runway) and a west option (2.8km in a straight line from Ma Tau Kok to North Point) as shown in Figure 2.4. The west option will require more dredging and is closer to the water sensitive receivers, and therefore has been taken in the water quality modelling as a worst case assumption.

2.9.6 Also, in accordance with the advice from HKCGCL, it is assumed that the new pipelines will be installed and commissioned by 2012 before decommissioning the existing pipelines in late 2013.

2.9.7 Opening a 600 m wide gap at the northern section of the former Kai Tak Airport runway may be required under the KTD as a mitigation measure to improve the water circulation and water quality at Kai Tak Approach Channel (KTAC). Based on the construction programme (Appendix 2.1), removal of existing seawalls at the 600 m opening of the runway would tentatively commence in early 2014 after completion of all the Stage 1 dredging works for construction of the cruise terminal at Kai Tak. It is possible that this programme could be accelerated slightly and noted that this will be a large complex structure and will take a long time to construct.

2.9.8 On the other hand, it is necessary to re-construct a short section of the existing seawall at the former Kai Tak Airport runway to allow for the new public landing steps cum fireboat berth for the KTD. According to the concurrent construction programme in Appendix 2.1, dredging works for the construction of the public landing steps would be completed in 2010.

2.9.9 There is a disused fuel dolphin at inner Kowloon Bay that would be decommissioned in the future. The fuel dolphin structure and its connecting fuel pipelines are considered as part of the fuelling facilities of the former Kai Tak Airport and hence the possible water quality impacts arising from the decommissioning of these facilities have been reviewed under the EIA Study for Decommissioning of the Former Kai Tak Airport other than the North Apron. The fuel dolphin will be demolished down to 1m below existing seabed while the disused fuel pipelines will be left in place and, if necessary, grouted with concrete. This approach will eliminate the need for any major dredging, filling, and sediment disposal activities and hence reduce the environmental impacts associated with the decommissioning works. According to the current PODP of KTD, there would not be any permanent works for KTD required at the existing location of the disused fuel dolphin. The programme for decommissioning of the fuel dolphin is unconfirmed at this stage but the current tentative schedule is to carry out the required decommissioning work no earlier than late 2009.

2.9.10 It should be noted that the Central Kowloon Route and Road T2 will join up to provide an east-west road link across Kowloon, from Tseung Kwan O in the east to West Kowloon in the west. Road T2 includes an immersed tube section from Cha Kwo Ling to the South Apron area of the former airport. The road is then at-grade connecting to the Central Kowloon Route near the north end of the former runway. The Central Kowloon Route then enters a short section of immersed tube in inner Kowloon Bay before entering a tunnel beneath To Kwa Wan. Both the immersed tube sections of Road T2 and CKR will require dredging.

2.9.11 The construction program for CKR and Road T2 is unavailable at this stage. It is likely that these two concurrent works cannot commence before 2012. For the purpose of this EIA, it is assumed that construction of the CKR and Road T2 would coincide with the cruise terminal Stage 2 dredging for worst case assessment.

Other External Activities

2.9.12 Based on the information available from the Wan Chai Development Phase II (WDII) Planning and Engineering Review, construction of the WDII will commence in 2008 for completion in 2016. Based on the approved EIA for Further Development of Tseung Kwan O (TKOFS), Phase I reclamation works at TKO would commence in 2010. Based on the latest information obtained from CEDD under this EIA, the Phase 1 seawall construction would commence in early 2012. These marine works could cause potential cumulative impacts with the proposed dredging works for cruise terminal.

2.9.13 Construction of the Western Cross Harbour Main is currently scheduled to complete in 2009 which might cause potential cumulative impacts with the proposed Stage 1 dredging works. Stage 2A of the Harbour Area Treatment Scheme (HATS) is currently scheduled for implementation in 2014. However, no marine work is anticipated within the Victoria Harbour for construction of the HATS Stage 2A.

2.9.14 A new landing facility will be built at Lei Yue Mun under the Lei Yue Mun water enhancement project. Construction of the landing facility would require dredging off the landing area and construction of a new breakwater. The Hong Kong offshore wind farm project involves burying a submarine transmission cable connecting the land point at the southeast of Junk Bay to the offshore wind farm in the Mirs Bay WCZ. Both of these marine works may contribute cumulative impact with the cruise terminal dredging.

2.9.15 Further elaboration of these external marine works and detailed development of water quality assessment scenarios are provided in Section 5.6 of this Report.