2.                         DESCRIPTION OF THE PROJECT

2.1                      Introduction

2.1.1                 In the past 20 years, a great deal of attention has been given to the redevelopment of the Yau Tong Bay area.  On 17.6.1992, the then Governor directed the Town Planning Board to expand the coverage of the draft Cha Kwo Ling, Yau Tong, Lei Yue Mun Outline Zoning Plan to include Yau Tong Bay.  Majority of the marine lot owners, in response to the Government new planning intention, has subsequently agreed to form the joint venture in cleaning up the dilapidated marine lots and redeveloping the area into productive and more friendly land uses.

2.1.2                 In recycling the dilapidated bay for a sustainable new land use, high regards have been given to the residential land use in the surrounding, the accessibility of environmentally-friendly transit in the door step, the new criteria of environmental protection as well as public expectation to early urban renewal actions.  It is highly essential to both Government and Community that this environmentally damaging brownfield site is able to be recycled in a timely manner, thereby removing the stigma of further contamination, accelerated environmentally degradation and potential liability associated with the bay area.

2.1.3                 Broadly speaking, the recommended engineering works and the refined development scheme as a result of careful evaluation of options are able to accomplish and contribute to the following major public benefits:

·       protects the healthy harbour;

·       aquatic habitat safeguarded;

·       eliminates further contamination to land, sea and air;

·       removing undesirable, incompatible and environmentally damaging uses;

·       land reserved for new community and recreational facilities;

·       a public transport oriented community;

·       a healthful living environment;

·       use of public fill materials as main source of fill;

·       sustainable layout design e.g. school in less noise sensitive locations, step-height pattern, urban-design approach;

·       sensitive construction program to eliminate the industrial/residential interface;

·       environmentally friendly reclaimation method without dredging. 

 

2.2                      Site Location and History

2.2.1                 The site is located in the eastern side of Kowloon to the south of the Eastern Harbour Crossing and is in an area of existing development. The site is bounded on the north and to the east by Cha Kwo Ling Road and existing development, to the south by Ko Fai Road and existing development and to the west by Victoria Harbour.  Figure 2.1 shows the location of the existing Yau Tong Bay.  An aerial photo showing the existing YTB is contained in Appendix 2A.

2.2.2                 The existing YTB is characterised by two distinct areas – land area of YTB marine lots and seabed of the bay.  The land area, which is generally level ground and is developed for industrial uses at present.  The seabed of the bay is at about -2mPD at the eastern end of YTB and drops to a maximum of -11.39mPD at the mouth of YTB. The seabed level was interpolated from the result of preliminary site investigation.

2.2.3                 The main source of information on the history of the site is from the aerial photographs.

2.2.4                 The majority of the existing land areas of the site have been operated as shipyards, timber yards or sawmills since the late 1950s.  The aerial photograph for 1963 shows the site was completely undeveloped.  In 1964, the present coastline was formed as reflected from Hong Kong Geological Survey (1:20 000) Geological Map Sheet 11 - Hong Kong and Kowloon.  In mid to late 1960s, Cha Kwo Ling Road was constructed westwards along the northern side of the site and excavation of hillside to the east and south was undertaken.

2.2.5                 The high-rise developments to the east and south of the site were constructed in the late 1960s to mid 1970s. After that, there was no major change to the site.  Currently, most of the Yau Tong marine lots (YTML) are operated as shipyard, timber yard, sawmill, material storage, concrete batching plant and industrial building.

2.2.6                 The proposed reclamation site is significantly zoned as Comprehensive Development Area (CDA) on the current Cha Kwo Ling, Yau Tong, Lei Yue Mun Outline Zoning Plan No. S/K/15/13 (Appendix 2E).  At present, the current CDA zone at Yau Tong Bay covers a total area of about 17.4ha for accommodating 18,000 persons.  In the proposed Yau Tong Bay CDA which was endorsed by Town Planning Board in December 1998, the population of the development is about 39,000 persons.

2.3                      Extent of Reclamation

2.3.1                 The existing YTB has been zoned as Comprehensive Development Area (CDA) on the gazetted Cha Kwo Ling, Yau Tong, Lei Yue Mun Outline Zoning Plan No. S/K/15/13. The extent of YTB reclamation in this gazetted OZP is represented by Line 1 in Figure 2.2. This reclamation limit, or simply named as Gazetted Reclamation, has already been approved by the Metro Planning Committee (MPC) of the Town Planning Board (TPB) since 1992 when the Yau Tong Bay was first zoned as CDA.  The area of reclamation within the Gazetted Reclamation is about 9 hectares.

2.3.2                 A request for rezoning of Yau Tong Bay CDA was submitted by David C Lee Surveyors Ltd. on behalf of Main Wealth Development Ltd. on 1 August 1998 and approval in principle was given on 11 December 1998 (the “1998 Approval”) by the MPC.  The approved Master Layout Plan under the aforesaid planning submission is shown in Appendix 2D.    In the aforesaid submission, the extent of YTB reclamation together with the boundary of Yau Tong Bay CDA were revised taking into account the coastal alignment of the proposed Western Coast Road (WCR) which runs from Tseung Kwan O to the South East Kowloon along the existing coastline. Territory Development Department (TDD) is the project proponent of the WCR.  This coastal alignment of WCR was recommended in the report of “The Feasibility Study on Alternative Alignment for the WCR” issued by TDD in 1999 and is named as “WCR – Coastal Option currently.

2.3.3                 Recently, TDD conducted another study named “Preliminary Feasibility Study on Tunnel Alignment Option of Tseung Kwan O Western Coast Road”.  The Final Report of this study was issued in December 2000.  The consultant of TDD recommended an alternative alignment for the WCR, which is named WCR - Tunnel Option.  In this option, the WCR starts from Tseung Kwan O to the South East Kowloon via an inland tunnel instead of running along the existing coastline.  The additional reclamation at the mouth of Yau Tong Bay for the foundation of the WCR viaducts is no longer required and the extent of reclamation has to be changed.  The study has found that tunnel option for WCR is preferable to the coastal alignment on environmental, planning and transport, engineering and programme grounds.  As advised by TDD, from the preliminary programmes, the WCR could be completed in around 2010/11 and there is still no final decision on which alignments to be adopted for the WCR.

2.3.4                 As there are two different options for the WCR, the extent of Yau Tong Bay reclamation will be different for each WCR option.  In this EIA Study, the environmental impacts of the two different reclamation options will be assessed.

Yau Tong Bay Reclamation based on Western Coast Road – Coastal Option

2.3.5                 Yau Tong section of the WCR – coastal option is located at the mouth of YTB as shown in Figure 2.2.  Originally, the proposed viaducts of the WCR at this section would be constructed over the sea.  In order to minimise the conflict in marine operation during construction between YTB reclamation and WCR project, and also to allow a more economical construction method for the viaduct foundation of the WCR, it is proposed to extend the limit of YTB reclamation such that the viaduct foundation of the WCR could be constructed on land rather than an expensive marine structure construction.  Moreover, this reclamation option provides a 30m wide promenade along the seafront for enjoyment of the public and recreation use.  The extent of YTB reclamation based on the WCR – coastal option is represented by Line 2 in Figure 2.2 and is simply called Full Reclamation.  Line 3 represents the boundary of the proposed YTB CDA under this reclamation limit.  The proposed CDA boundary has been agreed and approved in principle by the MPC.


2.3.6                 In the Full Reclamation option, the total project area is about 28.5 hectares which comprises 9.6 hectares of Yau Tong Bay Marine Lots, 0.55 hectare government lots and 18 hectares reclamation.  The reclamation works consists of 14.2 hectares of Yau Tong Bay and 3.8 hectares seabed areas of the existing Marine Lots. Layout plan of the Full Reclamation is shown in Figure 2.2a.

2.3.7                 As mentioned above, the benefit of full reclamation is to provide reclaimed land for the foundation of viaducts of WCR to be built on land in order to reduce the construction cost of the WCR.  In addition, the extra-reclaimed land can provide a continuous waterfront promenade as recommended by the government.

2.3.8                 The proposed Full Reclamation option of Yau Tong Bay reclamation is larger than the Minimised Reclamation option in terms of area of reclaimed land as well as the volume of mud dredging and bulk filling.  The environmental impacts, especially water quality impact, associated with the Full Reclamation option within the same construction period and duration, are undoubtedly more significant than the Minimised Reclamation option or the Gazetted Reclamation. The Full Reclamation is, therefore, taken as the worst case scenario for the YTB Reclamation to facilitate the assessment of environmental impacts.  Logically, if the Full Reclamation option is shown to be environmentally acceptable with no insurmountable environmental impacts, the Minimised Reclamation option, with lesser impact, is also expected to be environmentally acceptable.

Yau Tong Bay Reclamation based on Western Coast Road – Tunnel Option

2.3.9                 Tunnel alignment is an alternative option for the WCR and is currently named as “WCR – Tunnel Option”.  The occurrence of this option was due to the strong objection from the public on the proposed coastal option of the WCR.  The tunnel alignment of the WCR runs from Tseung Kwan O to South East Kowloon via an inland tunnel instead of running along the existing coastline.  As such, the additional reclamation at the mouth of YTB for the foundation of the coastal option of WCR to be built on will no longer be required.  Under the provision of the Protection of the Harbour Ordinance, the area of reclamation will be minimised.  Line 4 in Figure 2.2 is the proposed alignment of YTB reclamation based on WCR – Tunnel Option and is simply called Minimised Reclamation.  The eastern boundary line of YTB CDA is the same as the reclamation boundary.

2.3.10              The line of Minimised Reclamation is chosen such that the required reclamation area for the development is minimised.  The proposed reclamation line aligns the coast from the west of the Site at the existing CED Maintenance Depot along Cha Kwo Ling Road to the corner of YTML No.1.  It will be curved slightly inward towards the inner part of the bay providing a streamlined coastline to minimize the effect of the reclamation on the hydrodynamics in the vicinity of the Site.  In this option, the total project area is about 21.5 hectares and the area of reclamation is reduced to 12 hectares approximately.  The layout plan of Minimised Reclamation is shown in Figure 2.2b.


2.3.11              No matter which reclamation options, Minimised or Full Reclamation option, will be adopted for the proposed Yau Tong Bay reclamation, there will be an adjustment to the reclamation limit currently shown on the OZP No. S/K/15/13.  The proposed Yau Tong Bay reclamation should comply with the presumption against reclamation principle in the Protection of Harbour Ordinance.  The reclamation limit of the two reclamation options will be proved to be no more than necessary in the following sections.

2.4                      Public Benefits of the Yau Tong Bay Reclamation

Concealment of Contaminated Marine Sediment

2.4.1                 The seabed of the existing Yau Tong Bay is highly contaminated by the discharge or contaminants released from the existing industrial operations of the surrounding marine lots, such as shipyards, sawmill or car repairing industry.  The degree of seabed contamination increases from the mouth of Yau Tong Bay towards the inner part of the bay.  Based on the vibrocore samples collected during the site investigation in January 1998, the profile of Class C contamination in the YTB seabed is summarized in Figures 2.3a to 2.3i.

2.4.2                 The contour values indicate the ratio of the measured heavy metal concentration in the Class C contaminated mud over the classification criteria for Class C contamination as defined in the EPD TC No. 1-1-92.  Physically, a ratio of 1 indicates that the heavy metal concentration in the marine mud just reaches the Class C contamination criteria, while higher ratios suggest that the marine mud is highly contaminated with heavy metal concentration exceeding the Class C contamination criteria.  The contamination profile indicated that the seabed is highly contaminated by heavy metal, particularly along the Gazetted Reclamation limit.

2.4.3                 Without the implementation of remedial measures or Yau Tong Bay reclamation, the existing seabed of Yau Tong Bay is a potential hazard to the future Yau Tong Bay CDA as well as the marine habitat.  Allowing the continuous operations of polluting industries along the seafront would worsen the current situation further.  The odour arising from the contaminated seabed may have the possibility to cause nuisance to the nearby residents especially during summer time.  Apart from the direct impacts to the nearby residents, the contaminated seabed may also endanger the public indirectly.  For example, fishing at waterfront, especially at promenade, is quite popular and is a leisure activity of most people nowadays.  However, the fishes caught at the contaminated Yau Tong Bay may be polluted.  Consumption of these polluted fishes would be harmful if not hazardous to health.

2.4.4                 Furthermore, berthing of marine vessels at Yau Tong Bay may also cause the release of seabed contaminants.  When these boats go moorings, their anchors may disturb the seabed causing the dispersal of contaminants.  These released contaminants may migrate towards the harbour under water current or ship movement.

2.4.5                 Removal of contaminated marine deposit of the seabed is an effective mitigation measure to minimise the environmental impacts to the existing and future residents of Yau Tong Bay.  However, the limitation on the quantities of dredging and dumping of contaminated and uncontaminated marine deposit is quite stringent.  Besides, potentially harmful substances will be unavoidably released from a large scale dredging process, which may cause serious pollution to Victoria Harbour.

2.4.6                 In order to minimise the adverse impacts of the contaminated seabed to the public and marine habitat, it is recommended to retain the contaminated marine deposit at its original position as far as possible and isolate it from the marine environment.  Concealing the contaminated Yau Tong Bay seabed by reclamation is an effective method to achieve this.  Although contaminants may release during dredging of seabed for seawall foundation construction, careful selection of seawall location and stringent control will minimise the impact during dredging.

Additional Benefits of Extended Reclamation Options Against Gazetted Reclamation

2.4.7                 The Gazetted Reclamation boundary covers up only part of the highly contaminated seabed of Yau Tong Bay.  It is believed that the adverse environmental impacts from the covered contaminated seabed under this Gazetted Reclamation will be mitigated.  However, the remaining untreated portion of Yau Tong Bay seabed in the Gazetted Reclamation option is still a potential hazard to the future Yau Tong Bay CDA and the marine habitat.

2.4.8                 As the whole Yau Tong Bay seabed is contaminated, the extent of the proposed Minimised Reclamation can effectively isolate the contaminated seabed from the environment.  An initial sediment sampling and sediment testing reveal that the toxic chemical compound contained within the portion of extend reclamation (area between Gazetted and Minimised Reclamation) was higher than the adjacent area immediately east to the proposed reclamation line.

2.4.9                 As mentioned above, the seabed along the Gazetted Reclamation limit is highly contaminated by heavy metal comparing with Minimised or Full Reclamation options.  Dredging of marine deposit for the construction of seawall foundation along this alignment might result in a high release of contaminants and harmful substances (e.g. heavy metal) into the Harbour.  Other environmental problems, such as the treatment and disposal of the highly contaminated dredged material, might also arise.  In this connection, the Gazetted Reclamation limit is considered not an environmentally suitable alignment for YTB reclamation.

2.4.10              The Minimised Reclamation covers up almost the whole Yau Tong Bay which can effectively contain and prevent all contaminants or poisonous substances in the highly contaminated Yau Tong Bay seabed from migrating into the marine water.  The Minimised Reclamation limit, not only helps to achieve the important community development objectives, but to eliminate the health hazards due to existing water pollution and soil contamination.

2.4.11              Line 3, represents the boundary of CDA in the WCR – Coastal Option, which is considered to be the best reclamation limit amongst the three reclamation options in view of minimizing the potential hazard of the existing seabed contamination on the public.  It covers up the whole contaminated Yau Tong Bay seabed and the degree of seabed contamination along its seawall is lower than those seawall alignments of Gazetted and Minimised Reclamation options.  However, under the Protection of the Harbour Ordinance, it involves a greater area of reclamation than the option of Minimised Reclamation.  With the consideration on the implications of seabed contamination, area of reclamation and the above-mentioned elements, the Minimised Reclamation is a more preferable extent for YTB reclamation.

Improvement to the Environment of Yau Tong Bay

2.4.12              Yau Tong Bay is currently characterised by industrial operations such as shipyards, timber yards, sawmills, construction materials storage, industrial building and vehicle repair workshops.  The existing environment of YTB is considered poor and is suspected to be polluted by the existing industry.

2.4.13              Several large scale housing projects in the vicinity of Yau Tong Bay have already been commenced or substantially completed.  Residents will move in gradually.  Reclamation of Yau Tong Bay and the subsequent development on the reclaimed land provide an opportunity to remove the existing polluting industrial operations at Yau Tong Bay.   It is undoubtedly to the benefits of everyone who lives or studies in Yau Tong for the bay to be reclaimed such that the nuisance caused by the polluting industrial operations could be removed as well.

2.4.14              The decommissioning of shipyards and demolition of building structures in the YTB reclamation project not only relieve the pollution problems such as noise impact, air quality impact, water quality impact, land contamination and visual impact, caused by the existing industries, but also provide land to achieve important community development objectives, such as provisions of schools and open space for continuous seafront promenade.

Reduction of I/R Interface Problem

2.4.15              Some of the owners of YTML have not reached an agreement with the Joint Venture.  The lots of these dissenting owners are YTML1, 2-4, 25-27, 73 and 74 which are currently operated as shipyards, sawmill, material storage or industrial building.  The opportunity for continued operation of these marine-related industrial activities is an unlikely event in the context of YTB redevelopment and loss of marine access.  The coexistence of industrial operations in the vicinity of residential area in the future CDA however remote in Hong Kong’s market economy has been assumed for analysis and is so called industrial / residential (I/R) interface.  Environmental impacts generated from I/R interfacing problems are presented in the Package 2 EIA Study – “Engineering Feasibility Study for the Comprehensive Development at Yau Tong Bay”.

2.4.16              Removal of marine access is a catalyst to expedite the cessation of these current industrial operations.  Indeed, the proposed reclamation lines (either Full Reclamation or Minimised Reclamation) will remove the marine access of all Yau Tong marine lots completely.  The change in Yau Tong Bay creates an incentive for the existing industrial landowner including those dissenting owners to redevelop their properties as part of the CDA and the whole area being developed under the control of the Town Planning Board.  In fact, Yau Tong Bay reclamation provides an opportunity not only to remove the adverse environmental impacts from existing industrial operations to existing and future nearby residents, but also to resolve the problem of I/R interface between the dissenting lots and future CDA. 

2.4.17              However, the Gazetted Reclamation option cannot completely resolve the problem of I/R interface.  From Figure 2.2 and the Draft OZP Plan no. S/K15/13, it is noted that the Gazetted Reclamation (Line 1) abuts an industrial zone where two existing industrial building, one is on the dissenting lots of YTMLs 73 and 74, a saltwater pumping station and a gas pigging station are located and their marine access still exists.  If these two industrial land parcels remain as industrial uses without any plan for rezoning, it will represent a source of I/R interface problem to the CDA.

2.4.18              If the CDA boundary is extended to the proposed reclamation line (either Full Reclamation or Minimised Reclamation), there creates an incentive for the existing industrial landowner to redevelop their property as part of the CDA.  In the absence of the incentive for the individual owners to jointly redevelop the Yau Tong Bay and carrying out the reclamation, the continuous operation of the shipyards will definitely frustrate the emerging role, changing nature and scenic value of the harbour, in particular the visual impact of its gateway location at the eastern inner harbour.  The impact to the adjoining housing development will be substantial and considerable.  These existing uses may become an environmental nuisance to the neighboring Housing Authority’s housing estates upon completion as well as the private residential development south of Ko Fai Road.

2.4.19              Contrarily, in the scenario of Minimised Reclamation (Line 4), the marine access for the dissenting lots is extinguished and the dissenting lots are in close proximity to the CDA.  This will encourage the dissenting owners to cease their current industrial business and change to another more profitable business.

2.4.20              An overly cautious approach to safeguard the existence of those incompatible land uses not only generate further environmental risk and neighborhood distress, chilling the urban renewal objectives but is against the market economy principle that may necessitate public subsidy in terms of quality housing and premium assessment.

Enhancement to Open Space Provision

2.4.21              The Central and East Kowloon Development Statement (CEKDS) study revealed a finding that there is a general shortage of open space in the Kwun Tong area.  According to the public consultation on “Planning Study on the Harbour and Its Waterfront Areas”, public benefits/access shall be emphasized for all development facing the harbour whereby the use of waterfront promenade and recreational / tourism facilities shall be encouraged as part of the redevelopment along waterfront to provide public open space for access and enjoyment of the public.  The promenade will also serve as a mode of transport that facilitates travel for pedestrians and possibly cyclists.  Cycle routes may be provided to promote tourism and encourage travel in an environmentally-friendly manner.  Moreover, the promenade will also be suitable to house various utilities.  The proposed development on the reclamation provides a natural sightline of the waterfront and will provide an ideal space for passive and even active recreation uses.

Additional Land Resource to GIC Facilities

2.4.22              Another shortcoming within the Kwun Tong area is the inadequate provision of school facilities.  Due to insufficient land allocation of educational purpose in Kwun Tong, the proposed development will be able to provide land resources for school provision (total 8 schools in the proposed Yau Tong Bay Development), on top of the school facilities already provided within the gazetted CDA to support the population growth in Yau Tong and the surrounding areas.

2.5                      Description of Scenarios with or without the Project

2.5.1                 Significant portion of the reclaimed area in this project has already been zoned as Comprehensive Development Area (CDA) under the current OZP No. S/K/15/13.  This proposed project is aimed to provide land and infrastructures for the future comprehensive development in order to accommodate 39,000 peoples approximately.

2.5.2                 The Site comprises more than 20 marine lots on which various types of industrial activities are still active.  Some of the industrial operations, for instance, shipyards and car repairing workshops are identified as potential source for causing land contamination and all the other industrial operations at YTB are suspected to be the sources of pollution.

2.5.3                 With the implementation of this project, the existing scattered, low-rise industrial building structures will be demolished and replaced by residential and commercial buildings.  In fact, these scattered industrial buildings create an unpleasant visual impact to the environment.  The decommissioning of shipyards will probably relieve the environmental impacts on land contamination, noise, water quality and air quality. 

2.5.4                 The Coastal Option and Tunnel Option are two possible options for the alignment of the WCR, there is still no final decision on which alignment to be adopted for the WCR.  If the Coastal Option is adopted, the viaducts of the WCR will be built at the mouth of Yau Tong Bay.  In current planning, the viaducts of WCR at Yau Tong section will be built over water by the means of marine piles.  The implementation of Yau Tong Bay reclamation will extinguish the marine access to the existing marine lots and will provide sufficient land for the foundation of WCR (Yau Tong section) to be built on land.  Through this arrangement, the construction cost of the WCR can be reduced.  Moreover, as the marine access is no longer required, the viaduct level of the WCR can probably be reduced.  The land underneath the WCR together with the proposed seafront promenade can be acted as recreation area for the public, for example, a continuous seafront promenade.

2.5.5                 If reclamation and subsequent development of Yau Tong Bay not proceed, it will become a potential hazard to the nearby residents and student.  The existing Yau Tong Bay engulfed by marine lots has now become a pool of stagnant water and a source of nuisance.

2.5.6                 Without this project, the industrial uses on the existing marine lots such as ship repairing, vehicle repairing, sawmill, industrial building, concrete batching plant and construction material storage may continue their operations for a very long period.  No one can estimate when they will be ceased.

2.5.7                 Housing Department has already commenced many large scale housing projects in the vicinity of the Site.  As a matter of fact, the stagnant water in the bay, together with the current industrial operations will cause nuisance to the residents of the housing estates when completed.  The harmful pollutants generated by the highly contaminated industry will affect the health of existing and Yau Tong Bay future residents.  Additionally, there will be some new schools opposite to Cha Kwo Ling Road of which one is in operation.  These schools are vulnerable to noise nuisance generated by the operations on the marine lots.  It is foreseeable that complaints from future nearby residents against the nuisance will pose a problem and pressure for the government.

2.6                      Construction Activities

2.6.1                 Except the quantities of works, the construction method, period and activities of the Full Reclamation and Minimised Reclamation options are basically the same.  Reclamation of Yau Tong Bay consists of two main types of works - Marine Works and Lands Works.

Marine Works

2.6.2                 The Yau Tong Bay reclamation will involve the construction of total length 300 metres new seawall at the western side of the Site facing to Victoria Harbour.  However, the type of seawall, whether it is a vertical caisson seawall, sloping seawall or sloping seawall with a quay deck, will be determined in the detailed design stage.  The new seawall will be situated on dredged foundation which will be formed by removing the soft marine deposit.  Rockfill will be placed onto the dredged seawall trench to form the foundation of seawall.  Vertical seawall formed by precast concrete blocks or sloping seawall will be built on the dredged seawall foundation.

2.6.3                 The recommended reclamation scheme and phasing were proposed based on engineering, amount of available land, programme and cost consideration. This option can be modified as the study progresses dependent on imposed constraints.

General Reclamation Areas

Alternatives on Reclamation Method

2.6.4                 The seabed of the existing Yau Tong Bay is covered by a thick layer of soft marine deposit.  Without any treatment for the marine mud and allowing the mud to consolidate naturally under the new fill of reclamation is an exceedingly slow process and resulting post development settlement which is unacceptable to the progarmme of the proposed development.  Treatment of mud stratum is necessary in order to cope with the development programme.  There are two main engineering methods for minimizing the settlement resulting from reclamation.  These two methods are dredged reclamation and “drained” reclamation methods.

Dredged Reclamation

2.6.5                 Dredging is a direct method for removing the soft material on the Yau Tong Bay seabed. It is a simple and rapid way to expedite the settlement rate of reclamation.  The removed soft marine deposit will be replaced by a suitable filling material usually sandfill or rockfill.  Reclamation by bulk filling can proceed after the removal of marine mud.  The volume of dredged material depends on the area of reclamation and the thickness of marine deposit.  From the results of site investigation carried out in January 1998, the thickness of marine deposit in existing Yau Tong Bay varies from 4m to 8m approximately.  The area of reclamation is about 18 hectares for Full Reclamation option (12 hectares for Minimised Reclamation option).  If the dredged reclamation method is used, the estimated volume of dredging for Full Reclamation will be about 1,080,000m3 (for Full Reclamation).

2.6.6                 As the seabed of Yau Tong Bay is suspected to be contaminated, the quantities of dredging shall be reduced as far as possible in order to minimize the release of contaminants into the harbour.  Moreover, the disposal of surplus dredged material, no matter contaminated or uncontaminated, would definitely induce another environmental problems.  Leakage of dredged material during transportation to disposal by marine barges is another environmental concern especially for contaminated materials.  As the quantities of dredged material would be tremendous, a huge number of trips of marine barges for disposal of the dredged deposit would be required.  The chance of leakage will be increased.  Therefore, dredging would be recommended only when essential in engineering points of view and shall be reduced to a minimal.   As such, dredged reclamation method is not recommended to be adopted for Yau Tong Bay reclamation although it is a fast and simple method of construction.


“Drained” Reclamation

2.6.7                 It is recommended to use a “drained” reclamation with preloading for general reclamation areas of Yau Tong Bay. Drained reclamation relies on the installation of additional drainage paths into the soft compressible marine deposits. These additional drainage paths shorten the overall drainage path of the soft compressible material resulting in quicker consolidation.  Preloading comprises subjecting the ground to a temporary load which is greater than the envisaged final loading. The aim of preloading is to speed up the rate of settlement and slightly over consolidate the ground, thus minimize the amount of residual settlement and enable the site to be handed over for other construction activities as early as possible.  Although drained reclamation involves a more complicated construction procedures and requires more resources, this reclamation method can greatly reduce the quantities of dredged material and requires lesser filling material comparing with the dredged reclamation method, which is considered more environmental friendly.  The details of the recommended scheme are presented below:-

·       Place Geotextile across the area to be reclaimed to prevent the formation of mud waves.

·       Place sand blankets of 0.5m, 0.5m and 1.0m thick across the site. Placement of sandfill by Grabbing or Pelican Barge. 

·       Installation of vertical band drains as a marine operation.

·       Bulk filling to +2.5mPD, or an appropriate level which breaks the mean high water mark.  Bottom dumping of fill material should be employed while there is sufficient depth of water.  After that, placement of filling material can be carried out by Pelican Barge.

·       Bulk filling to preload level.  Placement of fill by Pelican Barge with dump trucks and loader.

·       Surcharge period.

·       Remove preloading mount to formation level once the anticipated settlement of the preloading mount has been achieved.

·       Handing over the Site for utilities, infrastructure and foundation works.

2.6.8                 There are three reasons to place geotextile over the seabed to be reclaimed.  Firstly, to minimize seabed disturbance during filling processes and therefore reduce the amount of suspended solids in the water column. Secondly, to reduce the amount of intermixing between the seabed deposits and the placed fill material.  Thirdly, to minimize the risk of mud waves occurring.  The placement of a thin layer of sand blankets also helps to reduce the risk of mud waves occurring.


Alternatives on the Use of Filling Material

2.6.9                 In order to have a stable supply of filling material for reclamation, imported sand fill from PRC by barge is indeed a good selection for reclamation material.  Because of the physical properties of sandfill, the rate of settlement of sand filled reclamation is expected to be faster than the other filling material.  Also, less difficulty would be expected during reclamation. 

2.6.10              Although sandfill is quite a good material for reclamation, it is recommended to use public filling material whenever possible.  Except the need of rockfill for the foundation of the new seawall and the 1.5m thick drainage blanket (sand Blanket) directly overlying the marine mud which are considered essential in the light of geotechnical requirements, the use of public filling material generated by local construction industry will be maximized for Yau Tong Bay reclamation in order to alleviate the acute shortage of public filling capacity in Hong Kong.  The average filling rates of bulk filling are shown in Section 2.7.2.  The estimated volume of imported public filling material for reclamation including preloading mound is about 1.85Mm3.  The supply of public filling material will be arranged with the Public Fill Committee prior to the commencement of reclamation in order to ensure stable supply of public filling materials.

2.6.11              From engineering points of view, both sandfill and public filling material are suitable for Yau Tong Bay reclamation.  Considering the above-mentioned, the use of public filling material is recommended.  However, in case of unstable or insufficient supply of public filling material, sandfill will be used as a supplement to public fill for reclamation. 

Reclamation above the Submarine Water Main and Gas Pipelines

2.6.12              The WSD submarine cross harbour fresh water main runs from the seafront of Yau Tong Bay in Cha Kwo Ling Road adjacent to the existing Cha Kwo Ling Saltwater Pumping Station to Quarry Bay.  The water main provides potable water to one-third of Hong Kong from the Diamond Hill reservoir.  The Hong Kong China Gas Company (HKCGC) twin 600mm diameter cross harbour submarine gas pipelines run from Tai Koo Shing and pass through the gas pigging station installation on Cha Kwo Ling Road serving a large area of Kowloon.  It is understood from WSD and HKCGC that the water main and gas pipelines form an important part of the distribution network.  Diversion or reprovisioning of the pipelines is a time-consuming process and will cause disruption to the existing network.  Both WSD and HKCGC do not accept reclamation to be applied directly above their submarine pipelines.  As mentioned in the above sections, it is understood that reclamation can bury the contaminants in the seabed and prevent them from migrating into open water.  However, due to the constraint posed by the submarine pieplines, it is proposed not to divert these pipelines in order to reclaim this area.     

2.6.13              No matter which reclamation options will be adopted, it is recommended that a removable concrete decking supported on bored piles should be constructed above the submarine WSD 1400mm diameter fresh water main and twin 600mm diameter gas pipelines.  The decking is removable in order to enable emergency repair or maintenance of the submarine gas pipelines and watermain.  An access opening of minimum 35m x 10m will be provided in the piled deck to allow for routine maintenance of WSD Cha Kwo Ling Saltwater Pumping Station which is located adjacent to the decking. Rubbish, if trapped underneath the decking, can be easily removed through this opening on deck.  Also, it can prevent the accumulation of gas trapped underneath the deck in case of leakage of gas in the submarine pipelines. 

2.6.14              The function of the decking is to provide an open space to form a continuous promenade should government considers that a waterfront promenade is desirable.  Besides, the most important purpose of the decking is to create a smooth coastline with adjoining seawalls as well as hiding the esthetically unattractive bored pile seawall, between the new seawall facing the harbour and the existing seawalll of the CED maintenance depot.  Without the concrete decking, there will be an abrupt change in the coastline formed by the small embayment formed by the new vertical bored pile seawall and the existing seawall of the CED depot. 

2.6.15              The removable concrete decking is supported by a series of bore piles.  As the release of marine deposit during construction of bore piles is confined by the pile casing, it is considered that the environmental impacts in terms of water quality generated by bore pile construction is minimal comparing with dredging for conventional seawall foundation.  The decking is formed by precast concrete beams or slabs such that the casting of beams or slabs can be carried out in the precasting yard outside the Site, may be in mainland China.  The construction of bore piles for the decking could be commenced after the completion of bore piled seawall of Phase 2 reclamation.  As the removable decking is not a critical construction activity and the construction period is quite flexible, it can be carried out at any time after the commencement of the reclamation depending on the construction sequence and available resources proposed by the contractor during construction stage.

2.6.16              The removable concrete decking will form part of Yau Tong Bay reclamation which may be implemented and maintained by the Project Proponent of the project.  Construction and maintenance cost of the decking may be premium deductible.

Reclamation under Roads and Utility Reserves

2.6.17              It is recommended that the same scheme outlined above shall be applied for the reclamation beneath proposed internal roads except the fill material shall be compacted to achieve an over consolidation ratio of 1.2 under working conditions in the marine deposit.  This will reduce the residual settlements.

Reclamation at Proposed Box Culverts

2.6.18              It is recommended that the marine deposit at the foundation of the two main box culverts should be dredged to minimize the settlement of the culverts.  The preloading of culvert foundation will be started after bulk filling to the required level.  Details of culvert construction will be determined and agreed with DSD in detailed design stage.

Permanent Seawall (Except the Seawall adjacent to the Submarine Pipelines)

2.6.19              Except the seawall adjacent to the submarine pipelines, all permanent seawalls are recommended to be founded on dredged foundations.

2.6.20              Seawalls facing to Victoria Harbour will be designed as wave absorbing seawall with a wave-reflecting coefficient of less 0.5 in accordance with WBTC 3/95.  In order to achieve this, the use of sloping seawalls or vertical caisson seawall is recommended.  At locations where berthing of marine vessels is allowed, either a piled quay deck over the sloping seawall or a caisson seawall should be constructed.  Details of sloping seawall and vertical caisson seawall are shown in Appendix 2F.

Permanent Seawall adjacent to the Submarine Pipelines

2.6.21              Bore piled seawall in accordance with WSD requirements is recommended for the permanent seawall adjacent to the existing submarine pipelines.  This type of seawall will be costly and time consuming to construct, however it is the only solution which can satisfy the requirements of WSD currently.  The bore piled seawall is one of the possible solutions but it is not the only solution.  Alternatives to this costly type of seawall should be investigated during the preliminary or detailed design stages if necessary.

2.6.22              A temporary dredged seawall should be constructed in accordance with the WSD’s allowable dredging limit.  This temporary seawall is used to enclose the main body of the reclamation while the bored pile seawall is being constructed.

Temporary Reclamation Edge Structures

2.6.23              As described in Section 2.5, it is proposed to phase the majority of the reclamation on a rolling programme. This should preclude the need for temporary reclamation edge structures.  However, if there is a requirement for a temporary reclamation edge structure, one of the following should be used: vertical cantilever (braced bulkhead); vertical seawall; sloping seawall; or a 1:10 to 1:15 “beach” slope.

2.6.24              The leading edge of the reclamation should generally be formed using a 1:10 to 1:15 “beach” slope.

2.6.25              The southern edge of Phase 1a reclamation should be formed using a temporary sloping seawall which utilises the dredged foundation of the permanent culvert. This will ensure a clear marine access to the remaining reclamation construction.

2.6.26              The interface between the WCR reclamation and the Yau Tong Bay reclamation should be formed using a sloping seawall.

Temporary Culvert / Channel

2.6.27              It is proposed to provide a temporary culvert/channel along the existing eastern and southern seawall of Yau Tong Bay to collect and convey the discharge form the outfalls of the existing stormwater box culverts into the harbour.  This structure should utilise the existing seawall foundations wherever possible. The temporary culvert/channel should be constructed at the beginning of reclamation to prevent stormwater from the existing culvert from discharging into the embayment formed by permanent and temporary seawalls, otherwise, the polluted stormwater trapped in the embayment would affect the environment.

Lands Works

2.6.28              The area surrounding Yau Tong Bay currently consists of low-rise industrial building structures which include shipyards, concrete batching plant, timber yards and sawmills.  In order to allow the re-development of Yau Tong Bay, these existing building structures will be decommissioned and demolished.  The major land works involved in the reclamation of Yau Tong Bay are the demolition of existing building structures and land decontamination works which will be discussed in Section 7.

2.7                      Reclamation Phasing

Alternatives on Reclamation Phasing

2.7.1                 Several alternatives of reclamation sequences have been considered in the early stage of the EIA study of which two options are selected for further investigation.   

Option I:

2.7.2                 In this option, both temporary (adjacent to existing submarine pipelines) and permanent (facing to the harbour) seawalls will be built concurrently with the main body of the reclamation in order to shorten the construction period.  However, as the seawalls is still under construction during bulk filling, there is no physical barrier to prevent the dispersal of filling material into the harbour except some silt screens or curtains.  Although this is a fast track construction method, it would induce greater impact to the water quality of Victoria Harbour as well as the overall environmental.  As such, this reclamation sequence is not recommended.

                  Option II (Preferred Option):

2.7.3                 The following is a list of the assumptions and imposed constraints considered when formulating the reclamation phasing in this option:

·       Reprovision of the drainage culverts discharging into Yau Tong Bay.

·       Provision of land for the Coastal Option of Western Coast Road (WCR) construction

·       The WSD and Hong Kong and China Gas Co. pipe reserve in the northwest corner of the Site.

·       The reclamation works for this project will commence on February 2004.

·       The temporary channel / culvert has to be constructed before the bay is fully enclosed.

·       The bay should be fully enclosed, except for a 50m wide marine access, before the main filling works commence.

·       An average filling rate of 4,000 m³ per day, with a maximum of 10,000 m³ per day.

2.7.4                 The assumed average filling rate is based on :-

 

 

Filling Activity

 

Filling Method

Filling Rate

1.

Sand Blanket

Grabbing or Pelican Barge

(Delicately)

1,000 m³/day

2.

Bulk Filling below ‑4mPD

Bottom dumping

10,000 m³/day

3.

Bulk Filling above ‑4mPD

Pelican Barge

1,000 m³/day to 7000 m³/day (Average 4,000³/day)

2.7.5                 Placement of filling material for the sand blanket is of small amount.  After placement of the sand blanket, level of the western portion of the bay will be probably below -4mPD, therefore, bottom dumping can be carried out in this area. The average filling rate of the Pelican barges has been used instead of a higher value to counter act the uncertainty in the supply of filling materials under the following possible situations during construction. They are :-

·       Location and number of barging point of public fill, and also quality of public filling materials.

·       Size and number of marine vessels available.

·       Limitation on the number of marine vessels that allowed by Marine Department of the  Government of HKSAR to work at Victoria Harbour.

·       Congestion within Yau Tong Bay with other activities, i.e. marine installation of vertical band drains.

2.7.6                 In order to satisfy the above constraints, three construction phases have been proposed (Figure 2.4a-d).  Phase 1 is the main body of the reclamation.  Phase 2 is to reclaim the remaining area between the bore piled seawall and the temporary seawall.  Phase 3 is the concrete decking construction above the submarine pipe.

2.7.7                 Phase 1 will form the main body of the reclamation. The lines within the Phase 1 reclamation area represent the leading edge of the reclamation at each sub-phase.  Phase 1a is specifically reclaimed to provide land for the WCR construction.  Except for Phase 1a, the edge of each of the other sub-phases (1b, 1c, and 1d) should be formed by a 1:10 to 1:15 “beach” slope.  A temporary sloping seawall should be constructed along the southern edge of Phase 1a reclamation by utilizing the dredged foundation of the proposed culvert extension.

2.7.8                 Phase 2 of the reclamation is to reclaim the portion of land between the temporary seawall and the permanent bore piled seawall adjacent to the submarine pipelines.

2.7.9                 Phase 3 of the reclamation is the removable concrete decking above the submarine pipe reserve.

2.7.1                 The reclamation programme is presented in Appendix 2B.

2.8                      Designated Projects

2.8.1                 The Reclamation of Yau Tong Bay falls under Schedule 2, Part 1, C - Reclamation, Hydraulic and Marine Facilities, Dredging and Dumping” of the EIA Ordinance.  Under the item C.2 of the aforesaid category, this project is described as reclamation works (including associated dredging works) more than 1 ha in size a boundary of which is less than 100m from a seawater intake point”.

2.8.2                 The decommissioning of existing shipyards at Yau Tong Bay also falls under Schedule 2, Part II, item 17 – A facility for ship building or repairing more than 1 ha in size or with a lifting capacity in excess of 20 000 tonnes.

2.9                      Scope and Overall Approach to the EIA Study

2.9.1                 The scope of work for the EIA Study is detailed in the Study Brief No. ESB-0010/1998 attached in Appendix 2C.  In accordance with the Study Brief, environmental issues related to the following aspects are to be addressed:

·       noise impact;

·       water quality impact;

·       waste management implications;

·       land contamination impact; and

·       visual and landscape impacts.

2.9.2                 The scope also includes recommendation of mitigation measures, identification of residual impacts and proposing environmental monitoring and auditing (EM&A) requirements for the project.  The assessment methodology adopted in the EIA Study is in accordance with the TM on EIA Process.  Where quantitative predictions have been provided, the modeling methodology, input parameters and method of calculation have been discussed, reviewed and agreed with the relevant Government Departments.  It should be noted that worst-case scenarios or conservative assumptions have been considered where appropriate.