16. SUMMARY OF ENVIRONMENTAL OUTCOMES. 16-1

16.3 Integrated Protection Measures. 16-2

16.4 Mitigation and Enhancement Measures. 16-3

16.5 Summary of Key Findings and Recommendations. 16-5

16. SUMMARY OF ENVIRONMENTAL OUTCOMES

16.1 Overview

16.1.1.1 This report presents a detailed assessment of the potential environmental impacts associated with a proposal to construct and operate a new road link, the Tuen Mun-Chek Lap Kok Link (TM-CLKL).

16.1.1.2 The TM-CLKL project will be located largely in the north-western waters, an area already subject to large scale development and disturbance. The proposed alignment will, also, make landing in developed areas, namely the Pillar Point area in Tuen Mun, next to the River Trade Terminal and other industrial and commercial land uses, and in the North Lantau Transport Corridor at Tai Ho Wan. Overall, the proposed alignment is some distance from residential developments and will, therefore, cause minimal disturbance to the local community.

16.1.1.3 Notwithstanding, in respect of the ecology of the area, some areas of habitats on the land have ecology value, particularly at Tai Ho, although these would not be directly affected. From a marine ecology perspective, the proposed project will be constructed in waters, which are known to be a habitat for the important Chinese White Dolphins, fisheries and, also, contain other key species including horseshoe crabs, mangroves and seagrasses, although these will not be directly affected. This is an area already subject to considerable disturbance because of other development projects and existing uses.

16.1.1.4 Reducing the potential for impacts and maintaining the existing environmental conditions as far a possible has been a major objective of the assessment and in the selection of the preferred TM-CLKL route. The environmental assessment has clearly established the acceptability of the proposed project from an environmental perspective. It can be concluded from this work that there are no insurmountable unacceptable impacts associated with construction and operation of the new alignment. The environmental assessment process has enabled the identification of an environmental management regime and numerous specific mitigatory measures to ensure that any residual environmental impacts are kept to a practical minimum and well within acceptable bounds.

16.1.1.5 Further details of both the integrated and applied measures taken to avoid and minimise impacts to the sensitive environmental receivers in the study area are detailed below.

16.2 Alignment Selection

16.2.1.1 A detailed option assessment of various alignments has been undertaken at the commencement of the Assignment and the ultimate alignment selected on the basis that it was preferred on environmental grounds, as well as meeting all the necessary engineering and operational constraints and requirements. The proposed alignment has managed to avoid and minimise impacts through the following measures:

· combining the TM-CLKL southern landfall reclamation with the HKBCF to minimize reclamation area and habitat loss;

· combining the TM-CLKL southern landfall reclamation with the HKBCF to avoid the coral and horseshoe crab habitats at Tai Mo To inter-tidal and sub-tidal areas;

· as TBM is not possible for the southern connection from the southern landfall Lantau, a viaduct, as opposed to the immersed tube tunnel, has been selected to, also, minimise seabed disturbance and loss;

· avoiding large areas of dredging work and reducing impacts on the seabed and benthic community by using TBM instead of IMT;

· use of non-dredge reclamation techniques are proposed where possible to avoid sediment dredging and removal minimising impacts to water quality and ecological sensitive receivers;

· relocating the toll plaza from reclaimed land to Area 46, thereby reducing the extent of the northern landfall reclamation;

· for land based works, proposing to use land which is already disturbed and/or developed as far as possible, thus, avoiding natural terrestrial habitats; and

· works areas for site office and storage have been located on sites already used as works areas or are on disturbed and developed land.

16.3 Integrated Protection Measures

16.3.1.1 In determining the design, construction methods, equipment and sequencing, measures which would minimise and avoids impacts have been integrated as far as possible as follows:

· optimisation of the tunnel profile to minimise the generation of waste materials;

· maximisation of cut slope angles in order to reduce the amount of spoil generated and to minimise the footprint of the works;

· designing the toll plaza to provide sufficient permanent setback to protect the Grave G1 which interfaces with the works;

· selection of bored piling methods for the marine viaduct, thereby avoiding high-intensity noise impacts from percussive piling which is capable of inducing physical injury to Chinese White Dolphins;

· no ‘rainbowing’ methods associated with trailer barges;

· construction of seawalls to be advanced by at least 200m before reclamation dredging and filling can commence where possible;

· the use of bored piling within a metal casing for the marine viaducts of TM-CLKL and HKLR;

· where public fill is proposed for filling below +2.5mPD, the fine content in the public fill will be controlled to 25%;

· where sand fill is proposed for filling below +2.5mPD, the fine content in the public fill will be controlled to 5%; and

· reuse of C&D materials in the works site as far as possible.

16.3.1.2 The specific set of integrated protection measures for Sequence A include:

· formation of a temporary seawall enclosing Portion A of HKBCF (except for a few 100m gaps of marine access) to be completed prior to reclamation dredging and filling activities;

· a maximum of 30% public fill to be used for all seawall and reclamation filling below +2.5mPD for the HKBCF and HKLR projects;

· a maximum of 50% public fill to be used for seawall filling below +2.5mPD for TM-CLKL northern and southern landfalls;

· a maximum of 30% public fill to be used for reclamation filling below +2.5mPD for TM-CLKL southern landfall; and

· a maximum of 100% public fill to be used for reclamation filling below +2.5mPD for TM-CLKL northern landfall.

16.3.1.3 The specific set of integrated protection measures for Sequence B include:

· formation of seawall enclosing the main reclamation site of TM-CLKL (southern landfall) and HKBCF (except for a few 100m gaps of marine access) to be completed prior to reclamation dredging and filling activities, except for Portion D of HKBCF.

· installation of sheet pile wall next to the northern boundary of the HKBCF+TM-CLKL (southern landfall) to ensure floating type silt curtains can be applied effectively:

- before the completion of the sheet pile wall next to the northern boundary of the HKBCF+TM-CLKL (southern landfall), seawall dredging at the area north of the demarcation line of the Phase 1 and 2 of HKBCF will not be carried out;

- before the seawall within the area of Phase 2 of HKBCF is formed above +2.5mPD, except a few 100m gaps for marine access, the sheet pile wall at the northern boundary of the HKBCF+TM-CLKL (southern landfall) will not be removed; and.

- before the whole perimeter of seawall for HKBCF+TM-CLKL (southern landfall) is formed above +2.5mPD, except a few 100m gaps for marine access and portion D of HKBCF, no dredging and reclamation filling will be carried out within the seawall boundary. Dredging for the formation of the pits for the subsequent Mf sediment backfilling within the HKBCF boundary is an exception;

· for the construction of seawall of HKBCF and TM-CLKL (southern landfall), only fill material with less than 5% fine content (e.g., sand and rock) shall be used for the seawall trench filling below +2.5mPD. For TM-CLKL southern landfall, the seawall filling shall consist of at most 50% of sand fill;

· a maximum of 30% public fill to be used for all seawall and reclamation filling below +2.5mPD for HKLR;

· no soft public fill to be used for all seawall filling below +2.5mPD for HKBCF;

· a maximum of 30% public fill to be used for reclamation filling below +2.5mPD for HKBCF reclamation and TM-CLKL southern landfall;

· no soft public fill to be used for seawall filling below +2.5mPD for the TM-CLKL southern landfall and at most 50% of sand fill will be used for the seawall filling;

· a maximum of 50% public fill to be used for seawall filling below +2.5mPD for TM-CLKL northern landfall;

· a maximum of 100% public fill to be used for reclamation filling below +2.5mPD for TM-CLKL northern landfall; and

· cage type silt curtains (with steel enclosure) will be applied round all grab dredgers during the HKBCF and TM-CLKL southern landfall seawall dredging.

16.4 Mitigation and Enhancement Measures

16.4.1.1 In addition to the integration of environmental considerations into the design of the project, a number of specific mitigation construction and operational phase measures have been identified to minimise potential adverse environmental impacts. A complete listing of all recommendations and mitigation and enhancement measures is provided in the Implementation Schedule and the Environmental Monitoring and Audit Manual which accompanies this report in Appendix A1. A summary of the most significant of these mitigation measures to protect key sensitive receivers is presented below:

· watering and dust control measures;

· bored piling monitoring to protect the Chinese White Dolphin;

· pre, during and post construction dolphin monitoring;

· 250m dolphin exclusion zone for use during dredging, reclamation, sheet and bored piling works;

· avoidance of the peak calving season of May and June during the installation of metal caisson during bored piling works;

· acoustic decoupling methods for use during reclamation and dredging works;

· marine vessel control specifications;

· deployment of an artificial reef of equivalent size as mitigation and deployment of an AR of twice the size to be affected as an enhancement measure;

· site hoarding for the protection of pitcher plants and surrounding habitat;

· coral translocation as an enhancement measure;

· culverting works of steam NL1 in North Lantau is undertaken during the dry season;

· 33ha of planting as an enhancement measure for vegetation loss;

· silt curtains (cage type) to be applied round all grab dredgers during the HKBCF, HKLR and TM-CLKL southern reclamation works;

· silt curtain to be deployed to protect the airport water intake;

· a sheet piled wall to be constructed north of the HKBCF island to allow the use of silt curtains during Phase 2 works; and

· single layer silt curtains will be applied around all works areas.

16.4.1.2 In addition, in order to address the cumulative impacts from all the projects and compensate for the cumulative Chinese White Dolphin and fisheries habitat loss, the Government has made a firm commitment to seek to designate the Brothers Islands as a marine park for enhancing the CWD habitat in accordance with the statutory process stipulated in the Marine Parks Ordinance. The designation of the proposed marine park would proceed after the completion of these projects. A study will be conducted to confirm the details of the proposed marine park before the commencement of the statutory procedures as stipulated in the Marine Parks Ordinance. The Government’s commitment to the marine park and its control and management in accordance with the Marine Parks Ordinance, as well as the Marine Parks and Marine Reserves Regulations, would significantly help conserve the CWD, and hence serves as an effective mitigation measure for the loss of CWD habitat arising from these projects. With this committed measures, the residual cumulative impacts to the CWD in terms of permanent habitat loss would be acceptable.

16.5 Summary of Key Findings and Recommendations

16.5.1.1 The proposed layout of the TM-CLKL represents the best available environmental option. Implementation of a comprehensive list of integrated and applied mitigation measures, as specified in the implementation schedule, are recommended along with the environmental management regime detailed in the Environmental Monitoring and Audit Manual.

16.5.1.2 With the adoption of these mitigation measures, the project will not result in any adverse residual environmental impacts and based upon the above, the following sensitive populations and areas have been protected:

· residents of the future Tung Chung East Development from additional noise;

· residents and commercial uses from construction dust;

· marine habitats and water quality through minimisation of reclamation areas, application of non-dredge techniques and measures to reduce sediment losses during construction;

· terrestrial habitats by minimising vegetation loss through use of previously developed and disturbed areas and compensatory planting;

· key floral species by installing protective hoarding prior to the works;

· coral communities by translocation prior to the works and providing habitat in the form of seawalls and a reprovisioned artificial reef as an enhancement measure;

· Chinese white dolphin by providing a range of mitigation measures during construction and operation to ameliorate and compensate for habitat loss and disturbance; and

· Grave at Tuen Mun area 46 by refining the design of toll plaza for setback and protection of Grave G1.

16.5.1.3 With the adoption of the recommended integrated and mitigation measures and the protection of the above sensitive receivers, the project is not predicted to result in any adverse residual environmental impacts. The project would fully comply with all environmental regulations and standards prevailing in Hong Kong.