TABLE OF CONTENTS
2.1 Purposes and Objectives of the Project
2.2 Site Location and Site History
2.5 Environmental Benefits of the Project
2.7 Scenarios “With” and “Without” the Project
2.8 Consideration of Different Development Options
2.9 Construction Methods and Sequence of Works
List of tables
Table 2.2 Summary of Comparisons of Breakwater Forms
Table 2.3 Summary of Comparisons of Proposed Wave Wall
Forms
Table 2.4 Summary of Options for Treatment of Soft Marine
Sediment Layer
Table 2.5 Summary of Non-dredged Seabed Stabilisation
Methods
Table 2.6 Summary
of Benefits and Dis-benefits of Two Construction Methods
Table 2.7 Summary of Key Components of Construction Works
Table 2.8 Summary of Key Construction Works for the
Project
Table 2.9 Summary of Key Public Concerns and Follow-up
Actions
Table 2.10 Summary of Potential Concurrent Projects
LIST OF FIGURES
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Project Boundary and Layout Plan |
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Comparison of Breakwater Structure Forms |
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Nautical Chart of Aberdeen Typhoon Shelter Area |
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Illustration of Construction Method – Proposed Breakwaters |
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Illustration of Construction Method – Proposed Land Access |
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Illustration of Construction Method – Proposed Wave Wall in the Form of Floating Breakwater |
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Locations of Potential Concurrent Projects |
(i) Proposed eastern breakwater, approximately 340 metre (m) in length, pointing to southwest with about 50 m tip bending southward, with open space and proposed marine access in form of public landing facilities (i.e. landing steps / ramp) and associated seabed stabilisation works;
(ii) Proposed western breakwater, approximately 300 m in length, pointing to northeast with about 85 m tip bending northward, with landing facilities for maintenance purpose and associated seabed stabilisation works;
(iii) Proposed land access, approximately 240 m in length, connecting the proposed eastern breakwater to Tai Shue Wan waterfront along the rocky shoreline within the Project boundary;
(iv) Proposed wave wall in the form of floating breakwater of about 110 m in length in the sea area within the ATS expansion area at a location approximately 70 m eastward of the tombolo between Yuk Kwai Shan and Ap Lei Pai;
(v) Modification of the crest of existing eastern breakwater to form a new open space with pedestrian access to Shum Wan Road; and
(vi) Modification of the existing western breakwater, which includes shortening of the breakwater by approximately 70 m with a view to straightening the navigation channel.
2.5.1.1 The design for the expansion of ATS will thoughtfully incorporate eco-shoreline features, including eco-tiles, tidal pools and seabird perch, of spanning about 570 m along the proposed breakwaters, land access and vessel impact protection system (VIPS). These elements aim to enhance biodiversity, improve ecological performance, and strengthen coastal protection, ensuring that the development aligns with principles of environmental sustainability and educational enrichment.
2.5.1.2 The subtidal portion of the proposed and modified breakwaters will create approximately 4.55 ha of artificial hard substrates, which could facilitate the colonisation of corals and other epibenthos. Additionally, the construction of the proposed land access connecting to the proposed eastern breakwater will create approximately 0.2 ha of artificial subtidal hard bottom habitat. Approximately 1,380 m of artificial intertidal habitat will be created through the construction of the proposed breakwaters as well as the proposed land access connecting to the proposed eastern breakwater. Artificial habitats created by the Project are summarised in Table 7.22.
2.5.2.1 There are sea caves along the Coastal Protection Area (CPA) at Tai Shue Wan and Ap Lei Pai, which serve as geological archives that provide valuable insights into coastal erosion and weathering processes. Thus, the alignment of the proposed land access has been designed to follow the rocky shoreline outside the CPA, allowing visitors to appreciate the area’s natural geological features, including sea caves. Currently, access to these sea caves is limited to marine transportation or kayaking, which restricts public accessibility. The Project will provide convenient access to the sea caves via the proposed land access, enabling the public to enjoy a closer view of the natural landscape and geological features such as sea caves for both leisure and educational purposes.
2.5.3.1 The construction and demolition (C&D) materials generated from the Project, including those arising from the demolition of part of the existing breakwaters, will be reused on-site whenever feasible. These materials will primarily serve as rock fill for the proposed structures, such as the foundation for the VIPS and landfall of proposed breakwaters. Moreover, substantial infill material is still needed for the breakwaters. To address this need, C&D materials generated by other local projects and accumulated in CEDD’s Public Fill Reception Facilities would also be used for the Project as infill materials. This approach will not only facilitate the beneficial use of a significant quantity of unwanted materials but also minimise the need to import raw material.
2.6.1.1 Through implementation of the Project, the ATS could be expanded by approximately 24 ha, offering additional sheltered space for vessels. This expansion is crucial in addressing the shortage of sheltered space for pleasure vessels as highlighted in the Section 2.4.2. The increased supply of sheltered space has the potential to yield social and economic benefits, particularly in fostering the growth of marine tourism. The merits of marine tourism development were further discussed in Section 2.6.2.
2.6.2.1 One of the key project objectives outlined in Section 2.1.1 is to support tourism, particularly focusing on marine tourism. The expanded typhoon shelter will enhance mooring capacity in the Hong Kong Island South, accommodating more vessels and facilitating visitor access via marine routes. When combined with other local attractions, the Project has the potential to generate substantial economic benefits. By creating a cluster of attractions in close proximity, visitors are likely to be incentivised to explore the area more extensively, resulting in increased economic activity and tourism revenue.
2.6.3.1 The Project proposed to shorten the tip of existing western breakwater by about 70 m in length to provide a straight passageway for marine vessels navigating to and from the existing Aberdeen South Typhoon Shelter. This modification eliminates the need for vessels to maneuver using a S-curve, which is comparatively more challenging and poses greater risks within the typhoon shelter area. The details of shortening of existing western breakwater are discussed under Section 2.8.4.3.
2.6.4.1 The creation of new open space through access to the crest of the proposed eastern breakwater offers a multifaceted approach that intertwines educational enrichment and sustainability promotion. Information boards will be installed in this open space to provide visitors with informative content about the surrounding environment, including details about sea caves, marine life, and ecological significance which will promote awareness and appreciation of natural habitats.
2.6.4.2 Sustainable technologies and facilities, such as solar/wind-powered lighting, weather monitoring, information boards, and a microalgae green wall, will be integrated to reduce electricity consumption and the Project’s carbon footprint. This showcases innovative renewable energy applications for urban development and environment.
2.6.4.3 The existing eastern breakwater, which features a concrete crest that is currently inaccessible to the public, is proposed to be modified to create a new open space. Through thoughtful landscaping, this open space will have synergy with the surrounding attractions, offering a relaxing spot at ATS for public enjoyment. This modification will also enhance the visual integration of the breakwater with neighboring developments and attractions.
Scenario with the Project
Scenario without the Project
2.8.2.1 The area around the southern part of ATS is a popular location for yachting / boating. It is within reach of appealing locations in the Southern District (e.g. Ocean Park, and beaches in the Deep Water Bay and Repulse Bay areas) and easily accessible by both public transport and road network. It also provides services of shipyards/marine engineering workshops along the coastline, possesses a vibrant ambience as it is surrounded by the Wong Chuk Hang, Aberdeen and Ap Lei Chau areas where hotel, dining and recreational services are readily in place to accommodate different customer-orientations of both locals and visitors. Given the regional shortfall of sheltered space in Hong Kong Island South, expanding ATS from its southern part can satisfy the potential economic benefits of meeting the development of marinas, which is the preferred option.
2.8.2.2 The Project’s size was dictated by both the layout and location of existing and proposed breakwaters. The proposed typhoon shelter size is intended to be as large as technically feasible and cost effective. The landing point of the proposed breakwaters would be located away from the existing sea caves along the shoreline as far as possible. Constructing the breakwaters further outwards would result in a deeper seabed level and more severe wave conditions, requiring a more robust and technically challenging breakwater design, which would be less cost effective. The proposed typhoon shelter size allows for an efficient breakwater design that reduces the foundation footprint, thereby minimising disturbance to the seabed and its marine ecology. For the details of consideration, please refer to Section 2.8.3.
Proposed Eastern and Western Breakwaters
2.8.3.1 The expanded area of ATS is located at the Aberdeen Channel facing directly towards the South China Sea, which is mainly influenced by waves from the south/southeast direction. Various possible alignments of proposed breakwaters are reviewed and analysed in term of hydrodynamic performance in providing the required sheltered space. Table 2.1 summarised the considerations of alternative layouts and locations of the proposed breakwaters.
Table 2.1 Summary of the Considerations of Alternative Layouts and Locations of the Proposed Breakwaters
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Options |
Description |
Benefits |
Dis-benefits |
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Original Proposed Option |
· At east-west direction in parallel to the existing breakwaters of Aberdeen South Typhoon Shelter
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Nil |
· Not effective to attenuate wave coming from south/southeast direction |
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Proposed NE-SW Option
(Preferred Option) |
· Facing NE-SW direction · Adjusted landfall locations and comparable overall length of breakwaters |
· Attenuate the waves coming from the south/southeast direction effectively · Provide more mooring spaces with acceptable resultant wave heights · Provide unblocked sea view for the future users on the open space at the crest of breakwater |
Nil |
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· Designed width of navigation channel in between the two new breakwaters is proposed to be about 100 m |
· Make the best balance of providing the required operation spacing for two-way marine traffic while maintaining the attenuation capabilities of the breakwaters against wave propagations through the opening |
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· Strategic bend at the tip of both breakwaters |
· Enhance navigation safety for vessels entering and exiting the expanded ATS by enhancing the visual sightlines and improving the navigational experience for vessel operators, ensuring safer and more efficient access to the sheltered area |
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2.8.3.2 After detailed hydrodynamic analysis and assessment, an alternative orientation of breakwaters at Northeast-Southwest direction are proposed in lieu of the original proposed orientation at east-west direction in parallel to the existing breakwaters of Aberdeen South Typhoon Shelter as presented.
Proposed Wave Wall in the Form of Floating Breakwater
2.8.3.3 The original location of the proposed wave wall is on the top of the tombolo with the primary objective to attenuate the waves on the west side of the expanded area of ATS through the existing tombolo. This tombolo, formed by natural process, connects Yuk Kwai Shan and Ap Lei Pai, creating an eye-catching geomorphic feature. To preserve the natural scenery, the wave wall in the form of floating breakwater was proposed to be relocated offshore by about 70 m eastward within the project site which could provide the same wave attenuation performance while minimising the impact on the tombolo.
Proposed Land Access
2.8.3.4 To minimise the impact to the existing shoreline of Tai Shue Wan, particularly the existing sea caves, which falls within the CPA, the proposed land access connecting to the proposed eastern breakwater and Tai Shue Wan promenade is to be constructed offshore with shallow foundation. To protect the proposed land access against accidental vessel impact, VIPS in form of precast concrete blocks would be placed at the seabed alongside in front of the footing of land access. The consideration of using shallow foundations would be further discussed in Section 2.8.5.6.
2.8.4.1 With the introduction of new breakwaters, the existing breakwaters at Aberdeen South Typhoon Shelter will have a reduced demand for waves attenuation. Therefore, the demolition of the existing breakwaters could be considered as a viable option.
Proposed Revitalisation of Existing Eastern Breakwater
2.8.4.2 In view that there is possible direct pedestrian access from Sham Wan Road to the existing eastern breakwater, revitalisation of the existing eastern breakwater to provide open space is recommended instead of demolition of breakwater.
Proposed Shortening of Existing Western Breakwater
2.8.4.3 To enhance the safety of the navigation channel, modification to the existing western breakwater is necessary following the expansion. Various options of demolition including full demolition and partial demolition are reviewed and analysed in term of navigation safety and cost effectiveness. To resume the footprint of the existing breakwater for mooring purpose, it is required to demolish the breakwater structure as well as dredging at the seabed as deep as -10 mPD to -15 mPD to remove all hard materials. As the additional mooring space that could be provided by full demolition option is minimal, it is proposed to maintain the major part of the existing western breakwater insitu by shortening of part of the breakwater of approximate 70 m and removing the breakwater structure down to -5 mPD without dredging works at seabed, which could straighten the passageway for marine vessels to navigate to/ from the existing Aberdeen South Typhoon Shelter with sufficient water depth. This approach aims to avoid disturbing the seabed, thus minimise potential water quality impacts from the modification and generation of C&D materials while maintaining adequate water depth for vessel navigation.
Proposed Eastern and Western Breakwaters
2.8.5.1 The Project involves the construction of two breakwaters which shall be structurally safe and robust to protect the sheltered space against the actions of sea level, sea current and waves under both normal and extreme conditions. In general, the breakwaters will be either sloping type or vertical type as shown in Figure 2.2. The design considerations and constraints are described in Table 2.2 below:
Table 2.2 Summary of Comparisons of Breakwater Forms
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Options |
Description |
Benefits |
Dis-benefits |
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Sloping Type Breakwater |
· Consist of core overlain by underlayer and armour · Rock armours and/or precast concrete armours are placed in interlocked manner · The voids amongst individual armours provide porosity for dissipation of wave energy and potential space for habitat of marine ecology. |
· Generally, more aesthetically pleasing as they look more natural-like when rock armours are used · More effective to dissipate wave energy against wave overtopping · Require a lower overall seawall height and site formation level · Provides more opportunities for ecological-friendly elements such as tidal pools |
· Wider overall footprint and the associated area of foundation and seabed stabilisation works (i.e. DCM / dredging) if the rubble mound breakwater has a wide berm · Given relatively deep water at the proposed breakwater locations, the foundation, footprint, and overall volume of the sloping breakwater tends to be very large to accommodate the slopes. · Require extensive filling material · Less effective in a deep-water situation in terms of capital cost and construction time |
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Vertical Type Breakwater
(Preferred Option) |
· Usually adopted where berthing facilities are planned or navigation safety is warranted · Constructed using precast concrete caissons at deep water depth · withstand wave impacts on the wall and then transfer stresses to the foundation · Reduce wave energy entering the harbour mainly through wave reflection · Wave energy absorption chamber could be constructed where wave reflection from vertical face is of concern to navigation of vessels nearby, |
· More suitable to a deep water situation as it requires a smaller footprint and thus reduce the scope of seabed stabilisation as well as disturbance to the seabed · Construction time is normally shorter as the caisson units can be pre-fabricated off-site during the construction of the foundation works, thus have less impact on water quality, marine ecology and landscape · More area suitable for navigation compared with sloping type breakwater |
· Prone to differential settlement since the concrete caisson units are constructed as a continuous solid structure by connecting caisson units with crest structures · Requires robust seabed stabilisation to avoid settlement within its design life |
2.8.5.2 It was recommended to adopt vertical type caisson breakwaters as the main structural form while sloping rubble mound is adopted at the breakwater landfalls. Vertical type caisson breakwater would require a smaller footprint and thus reduce the scope of seabed stabilisation as well as disturbance to the seabed, and together prefabrication of breakwater components off-site, have less impact on water quality, marine ecology and landscape. Moreover, it provides more area suitable for navigation compared with sloping type breakwater as shown in Figure 2.2, which is crucial for marine traffic safety. Furthermore, the construction time could be significantly reduced with the use of pre-fabricated units. To alleviate the wave reflection effect from the vertical face of breakwaters, wave absorbing chamber will be provided at the overlapping sections of the breakwaters. The environmental benefits of using pre-fabricated units was discussed under Section 2.8.6.5.
Adoption of Floating Breakwater for the Proposed Wave Wall
2.8.5.3 The original location of the proposed wave wall was on the top of the tombolo. To preserve the natural scenery and the existing tombolo, the wave wall in the form of floating breakwater was proposed to be relocated offshore by about 70 m eastward within the project site which could provide the same wave attenuation performance while minimising the impact on the tombolo.
2.8.5.4 Considering the shallow seabed condition, the construction of the proposed wave wall generally will be either sloping type or floating breakwater type. The comparison are described in Table 2.3 below:
Table 2.3 Summary of Comparisons of Proposed Wave Wall Forms
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Option |
Description |
Benefits |
Dis-Benefits |
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Sloping Type Wave Wall |
· Consist of core overlain by underlayer and armour · Rock armours are placed in interlocked manner · The voids amongst individual armours provide porosity for dissipation of wave energy and potential space for habitat of marine ecology. |
· Generally, more aesthetically pleasing as they look more natural-like when rock armours are used · Provides more opportunities for ecological-friendly elements such as tidal pools |
· Potential seabed disturbance from seabed stabilisation (i.e. dredging / DCM) · Require filling material · Disturb natural environment and potential visual impact (i.e. relatively high freeboard) |
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Floating Breakwater Type Wave Wall
(Preferred Option) |
· Consist of precast floating pontoons and concrete sinkers · Placement of concrete sinkers on seabed without seabed stabilisation required |
· Preserve the tombolo located between Ap Lei Pai and Yuk Kwai Shan · Avoid disturbing the seabed, as it eliminates the requirement of seabed stabilisation by methods like dredging and filling or deep cement mixing (DCM) · Minimise the potential impacts on water quality and water flow from construction · Reduce visible footprint significantly due to its low freeboard of about 0.6 m during both high tide and low tide comparing with traditional sloping or caisson breakwater that would have a greater freeboard of about 5 m during low tide, minimising the visual impact |
· Routine maintenance may be required |
2.8.5.5 A pilot project of using floating breakwaters within Hei Ling Chau Typhoon Shelter successfully demonstrates the performance of floating breakwater. Considering the forecast waves on the eastern side of the tombolo located between Ap Lei Pai and Yuk Kwai Shan would have similar design magnitude and wave periods as in Hei Ling Chau Typhoon Shelter, a concrete floating breakwater of about 110 m in length anchored to concrete sinkers placed on seabed to serve the function of a wave wall is proposed. By adopting the form of floating breakwater, the wave dynamics and cost effectiveness could be further enhanced.
Adoption of Shallow Foundation for the Proposed Land Access
2.8.5.6 The existing shallow rockhead along the proposed alignment of land access presents a favourable opportunity for the adoption of shallow foundation. Moreover, as the proposed land access will be located within the sheltered area with less wave loading, use of shallow foundation could provide the required structural loading capacity. This type of foundation eliminates the need for extensive pilling works for construction, effectively reducing the disturbance to the seabed and marine ecosystem. The construction method will be discussed in Section 2.9 and Figure 2.5.
Construction Method for Breakwaters Foundation
2.8.6.1 The seabed in Hong Kong waters is in majority underlain by soft marine sediment of various thickness. Its shear strength is low and it is highly compressible that it will settle when it is loaded by the breakwater structures. Based on the review of nautical chart published by MD, there was a disused spoil ground within the site for the Project is shown in Figure 2.3. It was also revealed from the marine ground investigation data that the existing seabed at the footprint of the two proposed breakwaters is covered with a layer of marine sediment with thickness varies between 0.2 m and 26.4 m. The considerations of adopting different options to treat the soft marine sediment layer, which have been commonly adopted in local reclamation/marine works projects, are elaborated in Table 2.4 below.
Table 2.4 Summary of Options for Treatment of Soft Marine Sediment Layer
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Option |
Description |
Benefits |
Dis-benefits |
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Fully Dredged Method |
· Remove marine sediment in existing seabed for forming the breakwater base · A fully dredged trench will be required to form and fill by sandfill/rockfill or rockfill only, followed by laying of caisson breakwater units and associate components.
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· Ensure the stability and minimise the settlement of the breakwater structures · Well-recognised in past marine works projects in Hong Kong · Well proven technology in Hong Kong · Familiar by most of the local contractors · Better control of the stability and settlement as all the compressible soft sediment underneath the seawall are removed |
· Large amount of dredging causes significant impacts to the water quality due to the suspended solids (SS) · Noise impact and air pollution impact to the adjacent areas and marine ecology due to the large amount of dredging plant required on site with relative longer duration · Generate substantial sediment plumes with its associated adverse impacts to water quality and marine ecology, as well as large volumes of waste needing off-site disposal · Increase of the marine vessels trips for the transportation of the relatively large amount of dredged marine sediment and fill materials · Increased marine vessels trips will lead to increased impact to noise and air |
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Non-dredged method |
· Removal and disposal of soft marine sediment is not involved · Seabed stabilisation works shall be carried out to strengthen the soft marine sediment · Suitable construction method and plant will be adopted to tackle the constraint of the existing seabed which is a disused spoil ground covered with a layer of debris and fill materials |
· Significantly reduced demand of fill materials for filling of the dredged trench compared to fully dredged method · Significantly reduced marine vessels trips are required for transportation of dredged marine sediment and fill materials compared to fully dredged method · Cause less impact on water quality, ecology and fisheries due to the dredging works |
· Relative higher cost compared to fully dredged method
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2.8.6.2 Different non-dredged seabed stabilisation methods for strengthening soft marine sediments are summarised in Table 2.5 below.
Table 2.5 Summary of Non-dredged Seabed Stabilisation Methods
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Method |
Description |
Process Detail |
Benefits |
Dis-benefits |
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Deep Cement Mixing (DCM)
(Preferred Option) |
· In-situ ground treatment method injecting and mixing binder material, typically cement, simultaneously into soft soils, generating a compound cluster with higher strength and stiffness |
· Blanket layer of granular fill is placed on top of the original seabed to minimise any binder material escape to the waters · DCM plant mixes cement slurry into soil in the designated area with controlled penetration / withdrawal rates, injection rates, and blade rotation speed to achieve the required strength and size · Soft marine deposits are solidified with a rapid strength gain within 28 days. |
· Reduce the construction time as solidified DCM columns could swiftly support the caisson breakwaters and filling materials · Proven to be a reliable ground treatment in local projects such as the Airport 3rd Runway Reclamation System, Integrated Waste Management Facilities (IWMF) Reclamation, and Tung Chung New Town East Reclamation Projects. |
· Rely on availability of specialised DCM plants and machine |
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Sand Compaction Piles / Stone Columns |
· Improves soft ground by displacing sediment with compacted sand or aggregates / crushed stone columns |
· Using vibration to install sand or any other similar material into soft ground via a casing pipe and forms sand piles in the ground |
· Commonly adopted worldwide · Applied in HZMB and Shenzhen-Zhongshan Link projects |
· Potential bulging and deforming in clay layers which results in large movement of breakwater units · Relatively long construction time |
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Prefabricated Vertical Drains (PVDs) |
· Provide a passage for relieving excess pore water pressure in the marine sediment |
· PVDs are installed to penetrate through the marine sediment · Surcharging (additional fill, dewatering, or vacuum pressure) preloads sediment together with PVDs, reducing residual settlement in reclamation. |
· Accelerate the compression and pre-stress of soft sediments · Reduce the residual settlement in permanent reclamation level |
· Relatively large extent of fill embankment required · Relatively long construction time |
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Vacuum Preloading |
· Alternative to surcharging using vacuum pressure to consolidate soft sediments. |
· Vacuum pressure applied over a surface membrane and PVDs installed though the reclamation fill and soft marine sediments to extract pore pressure from sediments. |
· Help extracting pore pressure from the soft marine sediments · Accelerate consolidation of the soft marine sediment |
· Relatively long construction time |
2.8.6.3 In view of numerous environmental issues resulted from dredged method, e.g. water quality problem and dispersion of contaminant, DCM is adopted to avoid dredging works. DCM enhances the stability of the seabed and foundation for breakwater structures and hence reduce the risk of erosion and collapse over time. The enhanced stability and durability can contribute to the long-term protection of the coastal areas and reduce the need for frequent maintenance or reconstruction, which in turn decreases the overall environmental footprint of the Project.
Low-carbon Design for Construction
2.8.6.4 Green construction technologies, including low-carbon concrete and Glass Fibre Reinforced Polymer reinforcement, will be adopted where feasible to reduce the overall carbon emission from the production of conventional concrete and steel reinforcement.
Construction Method for Main Structures
2.8.6.5 The proposed works, including proposed breakwaters, land access, and floating breakwaters, could be constructed by prefabricated unit or cast in-situ method. Table 2.6 summarised the benefits and dis-benefits of these two construction methods.
Table 2.6 Summary of Benefits and Dis-benefits of Two Construction Methods
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Options |
Benefits |
Dis-benefits |
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Prefabrication Method
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· Minimise the need of construction transportation, thus minimise potential air and noise impacts. · Shorten construction time, minimising on-site potential environmental impacts and cumulative environmental impacts with concurrent project. · Better control of quality and workmanship for works in fabrication yard. |
· Require another trade of skilled workers and additional construction equipment for erecting prefabricated units. |
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Cast In-situ Method |
· Conventional construction method and require relatively less special skilled labour when comparing with other construction methods. |
· Longer construction time to carry out the breakwater construction where the volume of concreting works is massive. · Required frequent marine transportation of concrete to the site area, thus induce potential air and noise impacts as well as marine traffic issue. · Require substantial temporary steel platform/ falsework for construction especially the land access is to be constructed over water. · Use of water-stop formwork for concreting below water level thus more construction risk on safety and quality of workmanship. |
2.8.6.6 To further reduce the impacts on air, noise and water quality, the proposed breakwaters and floating breakwaters will be constructed with prefabricated units whenever practical. The units will be manufactured off-site in a controlled environment, thereby eliminating the need for on-site casting and curing of concrete. This approach may significantly reduce the duration and intensity of on-site construction activities, leading to a shorter construction period. Consequently, the potential for particulate matter generations, construction noise, and water pollution, such as runoff and sedimentation, will be minimised.
2.8.7.1 Given that the construction of the proposed breakwaters, involving seabed stabilisation works and caisson unit installation, has the longest duration compared to the proposed wave wall in the form of floating breakwater and proposed land access, these breakwaters works will commence first. The other works, such as proposed land access and proposed wave wall in the form of floating breakwater, can then proceed in parallel with the proposed breakwaters construction. This approach optimises the Project timeline by addressing the most time intensives works upfront.
2.8.7.2 To shorten the constriction period for the breakwaters, multiple work-fronts will be considered to allow different work activities to proceed in parallel. It is assumed that two work-fronts comprising sand blanket and geo-textile laying plants along with DCM plants will be deployed at the same time across various locations. Concurrent stabilisation of multiple seabed sections accelerates the overall construction and shortens the duration of potential environmental impacts, thereby enhancing the Project’s environmental performance.
2.8.7.3 For the details of construction sequence for each activity, please refer to Section 2.9.
2.8.8.1 It was originally proposed to provide two piers at Tai Shue Wan and Deep Water Bay under separate project. Upon review by the Government, it is decided to integrate the function of the proposed Tai Shue Wan pier, taking the form of landing steps with ramps, into the proposed eastern breakwater under the Project, so as to create synergy while saving overall costs[3].
2.8.8.2 The proposed public landing facility would adopt the structural form of a multiple landing steps with ramps, embedded into the vertical face of the eastern breakwater near the landfall. Fenders would be installed at the berthing face to protect breakwater structure. Typical marine facilities for public landing steps such as bollards, handrailing, marine notice board, etc. would also be provided to serve the intended pier function.
2.8.8.3 This integration will also enhance efficient utilisation of marine space for mooring and navigation purposes. The integration also averted the necessity for an extra concurrent project, thereby alleviating the additional environmental impacts that would arise from the construction of a separate pier at Tai Shue Wan, such as seabed disturbance and noise generation.
2.8.9.1 While the existing marine habitats within the Project are considered as very low to low ecological value, eco-shoreline features such as eco-tiles, tidal pools and seabird perch, are proposed to be integrated along the proposed breakwaters, land access and VIPS.
2.8.9.2 One of the anticipated benefits of these eco-shoreline features is the provision of resting areas for birds to hunt. This will be achieved by pre-casting cavities into the concrete structures above the high tide level, creating a habitat that enriches local biodiversity.
2.8.9.3 The eco-shoreline will facilitate the growth of marine flora and fauna. By incorporating irregular surfaces, the design will encourage the colonisation of marine organisms, promoting a balanced aquatic ecosystem in the area.
2.8.9.4 Upon completion of the Project, the overall resilience of the coastal areas against natural threats such as erosion and storm surges will be enhanced. This added protection will contribute to the longevity and stability of the coastal environment, safeguarding both ecological and human interests.
2.8.10.1 The proposed eastern breakwater crest will offer stunning view of Lamma Island, Aberdeen Channel and attractions along the ways, allowing the public to enjoy the attractive scenery. Public amenities with themes such as harbour steps, shade canopy, and weather-monitoring devices are proposed for the open space areas on the breakwater crest for leisure, learning and recreation activities. Those facilities are typically provided at other promenades within Hong Kong with no impact to environment and surrounding landscapes.
2.8.10.2 Sustainability is one of the key elements of this open space recreational area. Innovative green technologies (e.g. microalgae green wall to absorb carbon dioxide and improve air quality), renewable energy (e.g. solar panel) and educational pole (e.g. solar and wind hybrid lamp) will be proposed to reduce carbon footprint and promote public awareness of sustainability.
2.8.10.3 Education through features such as information boards highlighting local ecology and marine life can foster environmental awareness. Real-time weather and sea conditions can be shown through electronic display boards for public awareness.
Table 2.7 Summary of Key Components of Construction Works
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Construction Works |
Detailed Sequence |
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(i) Proposed breakwaters and public marine accesses
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(a) Localised removal of any hard obstructions may be required from the top 3 m of the seabed surface prior to DCM works commencing. (b) Placement of geotextile and sand blanket (c) Seabed stabilisation in form of DCM and dredging at shallow water locations · In shallow water locations, such as near to the landfall of the new breakwaters, minimal full dredging is suggested where DCM is not applicable. (d) Rubble mound filling for breakwater foundation and landfall · Rubble mound filling for the caisson foundation, will be proceeded after the completion of DCM construction. (e) Installation of precast concrete elements · The precast concrete elements, e.g., caissons or concrete armour units, can be progressed in parallel with DCM works. Those precast concrete elements can be delivered by units upon progressive completion of DCM works to reduce occupation of site spaces and simplify construction sequence. (f) Filling the caisson compartment · Filling of the caisson compartment will be carried out in parallel with the adjacent caisson installation. (g) Placement of scour protection at the two sides of caissons (h) Construction of caisson topside and marine access · Construct the public landing facilities within the footprint of proposed eastern breakwater · Construct the landing facilities for the purpose of maintenance access within the footprint of proposed western breakwater |
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(ii) Proposed land access connecting proposed eastern breakwater
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(a) Placement of levelling stone on the seabed to provide a levelled ground (b) Construction of approximately 240 m long elevated footpath by installing prefabricated/in-situ land access segments, supported by precast/in-situ columns and pad footings (c) Placement of VIPS in form of precast concrete segments in front of the elevated footpath structure |
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(iii) Proposed wave wall in the form of floating breakwater
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(a) Placement of concrete sinkers on the seabed (b) Installation of prefabricated floating breakwater units with anchoring by chains to concrete sinkers (c) Installation of breakwater crest elements (i.e. navigation lights) |
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(iv) Modification of existing eastern breakwater |
(a) Construction of pedestrian access road to breakwater crest by modification of the crest (b) Installation of breakwater crest elements (i.e. safety railing, information board, etc.) |
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(v) Shortening and modification of existing western breakwater |
(a) Removal of rock armour and fill material at the breakwater head up to approximately -5 mPD (about 70 m in length) (b) Placement of rock armour and fill material to make good the shortened tip (c) Re-construction of maintenance access and navigation light |
Table 2.8 Summary of Key Construction Works for the Project
|
Description |
Tentative Construction Programme^ |
|
Proposed Eastern Breakwater |
Q2 2026 to Q2 2030 |
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Proposed Western Breakwater |
Q2 2026 to Q2 2030 |
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Shortening of Existing Western Breakwater |
Q2 2026 to Q2 2029* |
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Modification of Existing Eastern Breakwater |
Q2 2026 to Q2 2029* |
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Proposed Wave Wall in the Form of Floating Breakwater |
Q2 2026 to Q2 2030* |
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Proposed Land Access |
Q2 2026 to Q2 2030* |
Notes:
^ The works could be conducted with concurrent work fronts, as assessed in the relevant Sections 3 – 10 under the worst case scenario.
* The duration of the construction works is about 1 year. The commencement of these works will depend on the future detailed design of the Project, the Marine Department’s agreement on the temporary navigation arrangement, the contractor’s resource allocation and the programme of interfacing projects (i.e. the proposed marina development), etc.
Table 2.9 Summary of Key Public Concerns and Follow-up Actions
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Item No. |
Key Concerns |
Follow-up Actions to be Taken |
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Key Concerns / Issues Received from Public Inspection of Project Profile |
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1. |
Needs of the Project |
The needs of Project (i.e. increasing demand for sheltered space) (refer to Section 2.4) and the benefits of the Project (refer to Section 2.6) are presented in this EIA Report and have also been highlighted at the DPC meeting of SDC.
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|
2. |
Potential impacts on the tombolo between Yuk Kwai Shan and Ap Lei Pai due to the proposed wave wall on top of the tombolo.
Relevant Environmental Aspects: - Water Quality (Section 5) - Marine Ecology (Section 7) - Landscape and Visual (Section 9) |
Considering public concerns raised during the earlier stage of the project and to preserve the tombolo, the wave wall is now proposed as a form of floating breakwater located at about 70 m east of the tombolo. No construction works will be carried out on the tombolo or adjacent land areas under the Project. Furthermore, the adoption of floating breakwater eliminates the need for non-dredged seabed stabilisation works (i.e. DCM), filling works or dredging works for its installation. This design approach minimises adverse impacts on water flow, water quality, seabed conditions and sediment deposition on the tombolo during construction and operation phases.
The design was also presented at the DPC meeting of SDC where it received positive feedbacks.
Assessments on water quality impact (refer to Section 5.6), marine ecological impact (refer to Section 7.7) and landscape and visual impact (refer to Section 9.6 - 9.7) were conducted under the EIA study to assess the potential impacts of the Project (including the proposed wave wall in the form of floating breakwater) to nearby environment. With the implementation of the mitigation/enhancement measures, no adverse water quality impact and visual impact are anticipated, and ecological impacts are considered acceptable.
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3. |
Potential terrestrial ecological impacts on wild boars habitat, which may lead to nuisance to the public |
The majority of the project works will be marine-based, thus terrestrial ecological impacts are not anticipated.
Referring to Environmental Impact Assessment for Tai Shue Wan Development at Ocean Park (Register No.: AEIAR-184/2014) in 2014, the wild boar population and their foraging locations are land-based and distant from the proposed breakwater's locations, where the works are primarily marine-based.
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Key Concerns/Issues received in Southern District Council Meeting |
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4. |
Potential increase in general refuse and associated potential impacts on water quality may arise from vessel activities within the expanded typhoon shelter area
Relevant Environmental Aspect: - Waste Management Implications (Section 6). |
According to current practice, floating marine refuse within the Aberdeen Typhoon Shelter is regularly collected by the Marine Department (MD)’s contractor as part of their daily operations. Domestic refuse collection services are provided to local vessels in Aberdeen Typhoon Shelter twice daily by MD’s contractor. For large-scale domestic refuse collection from local vessels within the typhoon shelter, the MD has established a 24-hour hotline to facilitate timely collection service inside the typhoon shelter.
With the implementation of waste management control practices, unacceptable environmental impacts (e.g. air and odour emission, noise and wastewater discharges) are not anticipated. Details are discussed in the waste management implications assessment (refer to Section 6.5).
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Table 2.10 Summary of Potential Concurrent Projects
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Project |
Reference Document (Register No. in EIAO |
Project Descriptions |
Construction Programme1 |
Distance to ATS Project Site |
Consideration in this EIA Study |
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|
Start |
Complete |
Construction |
Operation
|
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New Contaminated Sediment Disposal Facility at West of Lamma Island |
EIA Report (AEIAR-241/2022) |
Construction and operation of a new contaminated sediment disposal facility. Key construction activities include dredging of seabed for the formation of the contaminated mud pits (CMPs). Key operation activities include disposal of contaminated sediment and capping of the exhausted CMPs. |
2024 |
2037 (subject to disposal demand) |
approx. 11 km |
The first CMP is planned to construct for operation by 2025/2026. Other CMPs will be constructed and operated sequentially depending on the disposal demand. Subject to the disposal demand, the facility expected to have a service lifetime for up to 20 years. The construction and operation activities under the project may overlap with ATS Project. According to the approved EIA report for New Contaminated Sediment Disposal Facility to the West of Lamma Island (Register No.: AEIAR-241/2022), the potential water quality impact from the proposed marine dredging, backfilling and capping operations, including suspended solids (SS) elevation, sedimentation flux, dissolved oxygen depletion, sediment bounded contaminants and nutrients, were predicted to be temporary and localised, confined in the west of Lamma Island. The change in tidal discharge across the East Lamma Channel was predicted to be small (-1.0% to 0.7%). Given the large separation distance between the CMPs and the ATS expansion area (approx. 11 km), adverse cumulative impact due to concurrent marine activities with the Project as well as the change in flow regime is not anticipated. |
|
|
Improvement Dredging for Lamma Power Station Navigation Channel |
EIA Report (AEIAR-212/2017) |
Initial dredging and re-profiling of the Lamma Power Station Navigation Channel during construction phase. Selected high spot dredging and re-profiling of the Channel during operation phase, approx. once 4 to 10 years. |
2019 |
2020/2021 (recurrent operation dredging every 4 years starting from 2021) |
approx. 7 km |
The construction phase of the project was completed. No potential cumulative impact is anticipated. |
According to the approved EIA report for Improvement Dredging for Lamma Power Station Navigation Channel (Register No.: AEIAR-212/2017), recurrent dredging is required periodically to maintain the required depth of the Lamma Power Station Navigation Channel. The predicted extent of sediment plume was confined at the west of Lamma Island, with very limited impact near Ap Lei Chau (≤0.2 mg/L of SS elevations). The change in tidal discharge and flow velocity at the navigation channel were predicted to be very limited, and the overall impact on hydrology and flow regime in the study area is insignificant. Adverse cumulative impact is therefore not anticipated. |
|
Establishment of Fish Culture Zone at Po Toi (Southeast) |
EIA Report (AEIAR-248/2023) |
Establishment of a new FCZ at Po Toi. Proposed works mainly involve setup fish farm structures and mooring system at sea. The scale of construction work on-site is relatively small and the installation of fish farm structures are expected to be completed within a few weeks for each fish raft. |
2024 |
Subjected to future application and approval process |
approx. 15 km |
Subjected to future application and approval process, the construction and operation activities may overlap with ATS Project. According to the approved EIA report for Establishment of Fish Culture Zone at Po Toi (Southeast) (Register No.: AEIAR-248/2023), no marine dredging (both capital and maintenance dredging) is required. The potential water quality impact due to the proposed mariculture activities were predicted to be complied with the Water Quality Objective (WQO) criteria except for total inorganic nitrogen (TIN), which non-compliance were predicted due to the background TIN contribution in the southern waters (> 0.1 mg/L) and stringent WQO criterion for TIN in the Southern WCZ. The residual impact of elevation in TIN were further assessed and considered the impact would be negligible for water sensitive receivers (WSRs) beyond 0.6 km from the fish farms (refer to Section 3.10.2 of approved EIA report). The presence of floating structures of fish rafts would not exert significant drag on the tidal stream and no notable change in flow regime would be expected. Given the large separation distance between the fish farms and the ATS expansion area (approx. 15 km), adverse cumulative impact is not anticipated. |
|
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Route 11 (Section between Yuen Long and North Lantau) |
AEIAR-255/2023 |
Construction of Route 11 (Section between Yuen Long and North Lantau), covering areas in Lam Tei, So Kwun Wat, Tai Lam, Tsing Lung Tau and North Lantau. In respect to marine-based works, the project will include the construction of Tsing Lung Bridge, which is a suspension bridge, crossing over the Ha Pang Fairway, with reclamation for construction of bridge tower at Tsing Lung Tau. |
2026 |
2033 |
approx. 19 km |
The tentative construction programme for the reclamation at Tsing Lung Tau and construction of Tsing Lung Bridge may overlap with the ATS Project. According to the approved EIA report for Route 11 (Section between Yuen Long and North Lantau) (Register No.: AEIAR-255/2023), the modelling results showed that the potential water quality impact was localised. Given the large separation distance between the reclamation at Tsing Lung Tau and the ATS expansion area (approx. 19 km), adverse cumulative impact is not anticipated. |
The operation of the project will be after the construction phase of ATS Project. According to the approved EIA report for Route 11 (Section between Yuen Long and North Lantau), the modelling results showed that the overall hydrodynamic changes were insignificant. Given the large separation distance between the reclamation at Tsing Lung Tau and the ATS expansion area (approx. 19 km), adverse cumulative impact is not anticipated. |
|
Reclamation for Kau Yi Chau Artificial Islands |
Project Profile (PP-633/2021) & EIA Study Brief (ESB-349/2021) |
The tentative reclamation area of Kau Yi Chau Artificial Islands (KYCAI) development is about 1,000 ha. Marine-based works may include reclamation of the artificial islands and dredging of seabed for the rearrangement of anchorages in the vicinity of Kellett Bank |
2027 |
2029/2030 (complete first phase of reclamation) |
approx. 9 km |
Based on the information available at the time of preparing this EIA study, the Tsing Yi - Lantau Link (TYLL) (PP-653/2022 & ESB-359/2023) and KYCAI development (including Reclamation for Kau Yi Chau Artificial Islands (PP-633/2021 & ESB-349/2021), Kau Yi Chau Artificial Islands Development (PP-634/2021 & ESB-350/2021) and Hong Kong Island West - Northeast Lantau Link (HKIW-NEL Link) (PP-635/2021 & ESB-351/2021)), locating > 9 km away from the Project, are the major infrastructure projects in the Central Waters and will likely coincide with the construction and operation of this Project. Separate EIA studies will be/are carried out under the Environmental Impact Assessment Ordinance (EIAO) for these projects. According to the relevant project profiles, it is expected that non-dredged method will be adopted so as to minimise the amount of dredging required. Dredging rate and the grab descending speed will be controlled to minimise disturbance to the seabed and sediment loss during potential dredging works for the TYLL, HKIW-NEL Link and the rearrangement of anchorages in Kellett Bank. For KYCAI reclamation, reclamation filling will be carried out behind leading seawalls, together with silt curtain surrounding the works area to control the off-site migration of fine sediments from the DCM installation and reclamation filling operations. These mitigation measures would help to confine the sediment plume generated from the TYLL, HKIW-NEL Link and KYCAI development. Other specific mitigation measures will be explored further in their separate EIAs to control the cumulative impact within the acceptable level. Given the large separation distance between the proposed reclamations of these projects and the ATS expansion area (approx. 9 km for HKIW-NEL Link and KYCAI development; and approx. 15 km for TYLL), as well as the buffer between the predicted SS elevations (key parameter) and the allowable SS criterion on the identified WSRs, it is considered that the cumulative impact with the TYLL, HKIW-NEL Link and KYCAI development will not affect the environmental acceptability of this Project. Adverse cumulative impact is therefore not anticipated. |
|
|
Kau Yi Chau Artificial Islands Development |
Project Profile (PP-634/2021) & EIA Study Brief (ESB-350/2021) |
Development of KYCAI after reclamation. |
N/A2 |
2033/2024 (first population intake) |
approx. 9 km |
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|
Hong Kong Island - Northeast Lantau Link |
Project Profile (PP-635/2021) & EIA Study Brief (ESB-351/2021) |
Highway between KYCAI and Hong Kong Island, KYCAI and Northeast Lantau and KYCAI and Penny’s Bay. Marine works would be required for the construction of the whole Hong Kong Island – Northeast Lantau Link. |
N/A2 |
2033/2034 |
approx. 9 km |
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|
Tsing Yi - Lantau Link |
Project Profile (PP-653/2022) & EIA Study Brief (ESB-359/2023) |
Construction of bridges crossing Ma Wan Fairway and Kap Shui Mun Fairway, with possible reclamation for the construction and protection of bridge towers and anchorages. Marine-based works will be required for the construction of bridges including possible reclamation for the construction and protection of bridge towers and anchorages. |
N/A2 |
2033 |
approx. 15 km |
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1. The reference of programme is according to the project profiles / EIA study briefs / EIA report in the EIAO websites.
2. ‘N/A’: Construction commencement date not available.
[1] Marine Department (2022) Assessment of Typhoon Shelter Space Requirements 2022-2035
[2] Marine Department (2022) Assessment of Typhoon Shelter Space Requirements 2022-2035
[3] As for the proposed pier at Deep Water Bay, the proposal is put on hold by the Government until there is a clearer direction on the future development at the lower park of Ocean Park.