12 SUMMARY OF ENVIRONMENTAL OUTCOMES

12.1 Overview

12.1.1.1 Section 2 outlines the details and benefit of the Project together with the consideration of alternatives during the preliminary design stage, which has taken into account the findings of various engineering and environmental review. The technical assessments in Sections 3 to 10 have demonstrated that all the statutory requirements in EIA Study Brief (ESB-315/2019) and EIAO-TM have been compiled with.

12.1.1.2 This section summarizes the key environmental outcomes arising from this EIA study, the approaches that have been adopted to either avoid or minimize various environmental impacts throughout the design process, and the associated environmental enhancements and mitigation measures.

12.2 Environmental Benefits of the Project

12.2.1.1 The proposed Revised Trunk Road T4 is designed to provide a direct connection for through traffic between Ma On Shan area and Tsuen Wan / West Kowloon area bypassing the busy at-grade road network of Sha Tin Central. Road Users can be benefited from this direct connection route travelling between different districts such as Tai Wai, Ma On Shan, Tsuen Wan and West Kowloon etc. It is also identified as a medium-term mitigation measure to alleviate the traffic congestion in Sha Tin District, in particular, Tai Po Road (Sha Tin Section) and some major road junctions. With T4 in operation, not only the congested traffic problem at local road and junction in Sha Tin can be relief, but also improve the air quality and noise impact to residential premises nearby local road in Sha Tin as a result of relieving traffic congestion problems.

12.2.1.2 This section summarizes the key environmental outcomes arising from this EIA study, the approaches that have been adopted to either avoid or minimize various environmental impacts throughout the design process, and the associated environmental enhancements and mitigation measures

12.3 Incorporation of Environmentally Friendly Options

12.3.1.1 Avoidance of environmental impacts is one of the main considerations throughout elevation and development of alignment options. In case due to limitation of actual site situation that environmental impacts could not be completely avoided, environmentally friendly alternatives or designs were taken as much as practicable for compliance with relevant EIA requirements. The following approaches to avoid environmental impacts have been suitably incorporated into the layout of the preferred alignment option.

· Avoidance of conflicting with the existing Old and Valuable Trees (OVTs) along Chung Ling Road;

· Avoidance of erection of the proposed noise mitigation measure coincide with ardeid flight path; and

· Minimize encroachment of natural terrain hazard mitigation work into Lion Rock Country Park

Avoidance of conflicting with the existing Old and Valuable Trees (OVTs) along Chung Ling Road

12.3.1.2 The eastbound viaduct of Revised Trunk Road T4 is designed to lean at the southern side of Tsing Sha Highway near industrial buildings at Tai Wai instead of traveling along Chung Ling Road, thus avoid affecting the 5 nos. of OVTs during construction. Although minor at-grade road works will be carried out in the vicinity of the OVT, the work extent is anticipated outside the protection zone of OVTs. Nevertheless, proper tree protection measures shall be implemented for the OVTs adjoining the site boundary during the construction stage in accordance with relevant guidelines by DEVB which is described in Section 9 in details.

Avoidance of erection of the proposed noise mitigation measures coincide with ardeid flight path

12.3.1.3 The viaduct of the Revised Trunk Road T4 across Shing Mun River Channel (SMRC) is designed to descend at a maximum allowable gradient of 8% without erection of noise barriers/enclosures on the northern portion of the T4 bridge deck. The elevation of bridge structure is thus avoided the impact on flying height for majority of the ardeid according to observations from ecological survey. For balancing the noise impact without noise barriers /enclosures installed at the northern portion of the said T4 bridge deck, use of low noise road surfacing on the road section and provision of semi-noise enclosures at the southern portion of the T4 bridge deck across SMRC is proposed.

Minimize encroachment of natural terrain hazard mitigation work into Lion Rock Country Park

12.3.1.4 Historical natural terrain landslides located within the study area of the Project was validated from aerial photo interpretation (API) method using low altitude aerial photographs. In order to mitigate the potential landslide hazards from the natural terrain above existing Sha Tin Road (STR) to the operation and road users of the T4 and STR, stability works for the natural terrain which falls within Lion Rock Country Park (LRCP) is required. Debris resisting barriers instead of soil nailing is adopted to minimize construction works extent, and thus reduce the environmental impact to LRCP as far as practicable

12.4 Environmental Design Recommended

12.4.1.1 Other than initiatives to avoid environmental impacts as summarized in Section 12.3, further efforts have been exercised to minimize impacts. The need for any environmental designs required to mitigate the associated impacts have also been identified and will be implemented, as appropriate. A summary of these approaches is given below:

· Adoption of environmentally friendly construction method;

· Implementation of trip-ticket system; and

· Implementation of environmental monitoring and auditing system.

Adoption of Environmentally Friendly Construction Method

12.4.1.2 Precast construction method will be adopted as far as possible, with bridge deck formed from precast concrete sections which will be manufactured off site and joined together on site, which minimize the extent and duration of construction activities required on site and hence the potential environmental impacts in the vicinity during construction. Other construction methods will be considered only when precast construction method is not feasible.

Implementation of Trip-Ticket System

12.4.1.3 In order to monitor, document and verify the disposal of C&D materials at landfills and public fill reception facilities, as appropriate, and to control fly tipping, a trip-ticket system for disposal of construction and demolition materials would be implemented.

Implementation of Environmental Monitoring and Auditing System

12.4.1.4 In addition to the mitigation measures as described above (see more details in the Implementation Schedule of Recommended Mitigation Measures as given in Appendix 11.1), a comprehensive environmental monitoring and auditing programme would be implemented to cover various aspects of concern. An independent environmental checker would also be employed to ensure that all the necessary mitigation measures are implemented in a timely and orderly manner.

12.5 Key Environmental Problems Avoided and Environmentally Sensitive Areas Protected

12.5.1.1 Sections 12.3 and 12.4 have summarized the key approaches adopted in the current proposal to avoid, minimize and mitigate environmental impacts. Some of these approaches have contributed to avoid a number of environmental problems and to protect a number of environmentally sensitive areas. Table 12.1 presents the key environmental problems that have been avoided and any sensitive areas protected by these approaches.

Table 12.1 Summary of Key Environmental Problems Avoided and Sensitive Areas Protected

Design Approach	Environmental Problems Avoided and Sensitive Areas Protected
Adoption of environmentally friendly construction method (Section 2)	· Adoption of quiet piling method to minimise the construction noise impact.
Use of debris resisting barriers to replace soil nailing (Section 2)	· Minimise the impacts from construction works within Lion Rock Country Park.
Minimizing impacts of noise mitigation measures on ardeid flight path (Section 8)	· Minimize the disturbance on ardeid flight path
Avoidance of illegal dumping (Section 6)	· The recommended preventive measures would avoid/minimise the chance of illegal dumping.
Implementation of Environmental Monitoring and Auditing System (Section 11)	· Ensure all the recommended measures are properly in place and their effectiveness.

12.6 Environmental Protection Measures Recommended

12.6.1.1 Mitigation measures have been recommended to further reduce the environmental impacts during construction and operation phases of the Project. Key recommended mitigation measures and any associated benefits are summarized in Table 12.2 below.

Table 12.2 Key Recommended Mitigation Measures

Environmental Aspect	Mitigation Measure and any Associated Benefit
Air Quality Impact	· Implementation of dust suppression measures as required in the Air Pollution Control (Construction Dust) Regulation to minimize construction dust impact.
Noise Impact	Construction Phase: · NSRs are protected with implementation of quiet PME, temporary/movable barriers and full enclosure as well as good site practices during construction phase of the Project. The predicted mitigated noise levels arising from the Project at all NSRs selected for the construction noise impact assessment would comply with the EIAO-TM construction noise criteria during non-restricted hours and restricted hours except during examination period for Hong Kong Bible Research and Education Centre and Christ College. · It is recommended that the works area of these critical construction activities shall be restricted during the examination period of these schools. Minimum separation distance between the critical construction activities and the schools has been recommended. Operation Phase: · Low Noise Road Surfacing (refer Figure 4.3.1, Figure 4.3.2, Figure 4.3.3, Figure 4.3.4 for locations and extents): - Approx 180m at proposed slip road SR1-1 (LNRS1). - Approx 210m at proposed T4 (westbound) slip road (LNRS2). · Proposed Noise Barriers and Enclosures (refer Figure 4.3.1, Figure 4.3.2, Figure 4.3.3, Figure 4.3.4 for locations and extents): - Approx 60m of 2m High Vertical Noise Barrier (N1). - Approx 130m of 5m High Vertical Noise Barrier (N2). - Approx 100m of 5.5m High with 1.5m Cantilever (at 45 degrees) Barrier (N3). - Approx 50m of 2.7m High with 3.7m Cantilever (at 20 degrees) Barrier (N4). - Approx 170m Semi-enclosure (SE1). - Approx 390m Full-enclosure (FE1).
Water Quality Impact	· Implementation of the proposed mitigation measures including installation of cofferdam/watertight steel casing at the pier site for all pilling and excavation works in river, use of water pumps to collect any construction site runoff and ingress/seepage water within the cofferdam and watertight steel casing to the on-site wastewater treatment facilities for treatment to satisfactory levels before discharge, and deployment of silt curtains to completely enclose the cofferdam/watertight steel casing/temporary steel platform prior to setting up piling works, installation of cofferdam/watertight steel casing and demolition of temporary steel platform. · Implementation of site practices as outlined in ProPECC Note PN 1/94 to control and minimise site runoff and drainage. · Adoption of proper site management and good housekeeping practices to minimise the potential water quality impact due to spillage events. · Provision of silt trap for road drainage for removal of pollutants from storm water. · Collection and conveyance of sewage effluent from the proposed chemical toilets to the existing sewerage system.
Waste Management Implications	· Implementation of good site practices and waste reduction measures (e.g. reuse of construction and demolition (C&D) materials before off-site disposal or develop a materials recovery and recycling programme during construction and operation). · A Construction and Demolition Material Management Plan (C&DMMP) should be prepared in accordance with Section 4.1.3 “Construction and Demolition Materials” of the Project Administration Handbook for Civil Engineering Works. · Preparation of a Waste Management Plan (WMP), as part of the Environmental Management Plan (EMP). · Implement a trip-ticket system for each works contract in accordance with DevB TC(W) No. 6/2010 to ensure that the disposal of C&D materials are properly documented and verified. · Handling of chemical waste in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes, and disposal of chemical waste at licensed chemical waste recycling / treatment facilities. · Excavation and handling of sediments in accordance with the Air Pollution Ordinance (Construction Dust) Regulation. · Collection and discharging of leachate in accordance with the Water Pollution Control Ordinance. · General refuse should be stored in enclosed bins or compaction units separately from C&D materials. · An enclosed and covered area is preferred to reduce the occurrence of wind-blown light materials. · The recyclable component of general refuse, such as aluminium cans, paper and cleansed plastic containers shall be separated from other wastes. · Provision and collection of recycling bins for different types of recyclable waste shall be set up by the Contractor. The Contractor shall also be responsible for arranging recycling companies to collect these materials. · Warning signs should be put up to remind the designated disposal sites. CCTV should be installed at the vehicular entrance and exit of the site as additional measures to prevent fly-tipping. · The Contractor shall carry out an education programme for workers in avoiding, reducing, reusing and recycling of materials generation. Posters and leaflets advising on the use of the bins shall also be provided in the sites as reminders.
Land Contamination	· No land contamination impact would be anticipated from the Project, therefore, no mitigation measure is required.
Ecological Impact (Terrestrial)	· Carefully design the proposed T4 alignment and associated works to avoid direct impact to ardeid night roost site between HKHM and Man Lai Court. · To minimize the disturbance on ardeid flight path, no semi-enclosure would be installed at the northern part of proposed dual 2-lane flyover near HKHM, while installation and height of noise barrier at the southern part of proposed dual 2-lane flyover near the Riverpark would be minimized, as far as possible. · Use of tinted materials and superimposing dark patterns or strips on noise barrier. · Restricted hours for construction works as 16:30-07:30 during dry season (October - March) and 17:00-07:00 during wet season (April - September) are proposed within 100 m from the ardeid night roost site to minimize construction impact to ardeid night roost site · To avoid adverse impact to two plant species of conservation importance (Butulang Canthium and Ailanthus) recorded within the Project footprint and six flora species of conservation importance (Butulang Canthium, Incense Tree, Luofushan Joint-fir, Small Persimmon, Rhododendron spp. and Hairy-fruited Ormosia) in the vicinity of the Project footprint of flexible and rigid barriers, a detailed vegetation survey should be conducted prior to site clearance. A Plant Preservation and Transplantation Proposal should be prepared to present the findings of tree survey/detailed vegetation survey, preservation and/or transplantation methodology, implementation programme, and monitoring programme, where necessary. · Implement standard good site practices (e.g. dust suppression measure, glare control measures) throughout the construction phase to minimize disturbance impact to natural habitats and associated wildlife in the vicinity.
Landscape and Visual Impacts	· Preservation of existing vegetation. · Preservation of Old and Valuable Trees (OVTs). · Transplanting of Affected Trees to transplant particular interest and high amenity value trees unavoidably affected by the works. · Control of Night-time Lighting Glare. · Erection of Decorative Screen Hoarding to minimise the potential landscape and visual impacts due to the construction works and activities. · Management of Construction Activities and Facilities to minimise any potential adverse landscape and visual impacts. · Reinstatement of Temporarily Disturbed Landscape Areas to reinstate to equal or better quality of temporarily disturbed landscape areas. · Reinstatement of Affected Watercourses to minimize the disturbance to watercourses as far as practicable. · Compensatory Planting for Loss of Existing Trees to enhance ecological value and improve overall value of landscape setting. · Landscape Treatment on Slopes to maximize the greening provision along the road improvement works. · Provision of Screen Planting to soften the hard structural elements. · Maximization of Roadside Planting to maximize the greening effect. · Re-provision of Affected Open Space. · Visually pleasing aesthetic treatment on noise barriers and noise enclosures to echo with the visual context and character of the adorning transportation corridors. · Aesthetically pleasing design for footbridges, pedestrian subways, cycle paths, carriageways and other highways structures to minimise any potential adverse landscape and visual impact.
Impact on Cultural Heritage	· Conduct pre and post condition survey for Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage and Ng Yuen before and after the construction works, for better implementation of protective measures and to identify any damages that have caused by the construction. · Implement monitoring of vibration, settlement and tilting incorporated with a set of Alert, Alarm and Action (3As) system for Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage, Lau Ancestral Hall, Ng Yuen, High Rock Christian Camp and No. 1, 2 and 3 First Street, OLD1, OLD9, OLD11-21, OLD26-28 to ensure the indirect impacts, including ground-borne vibration, settlement and tilting would not cause damages to the built heritage. · Excavation works in close vicinity to Gatehouse of Pok Ngar Villa, Tsang Tai Uk, Li Cottage, Ng Yuen, OLD26 should not jeopardize stability of the historic buildings. It should not undermine or cause damage to foundation of the historic building. Foundation information of the historic building shall be verified on site if needed, sufficient lateral support should be provided and de-watering (if required) should be carried out with great cautions to control ground movement and change of ground water regime at the heritage site. · Foundation information of the historic building shall be verified on site if needed, sufficient lateral support should be provided and de-watering (if required) to ensure stability of the historic buildings. · Set up physical barriers for Li Cottage, Ng Yuen and OLD26, and buffer zones with physical barriers for Tsang Tai Uk, Gatehouse of Pok Ngar Villa and OLD26, to avoid direct impacts of damages through contacting with construction machineries and site negligence. · Protective covering of plastic sheets shall be provided for Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage and Ng Yuen during construction to avoid impacts of dust nuisance. · Fencing should be set up to clearly demarcate buffer zones, so as to avoid damages of site negligence.

12.7 E stimation of Population Protected

12.7.1.1 Population and environmental sensitive areas in the vicinity of the Project site have been protected through the avoidance and/or minimization of environmental impacts from the construction and operation of the Project. Population protected from air quality impacts include air sensitive receivers within 500m from the Project Boundary including residential buildings, commercial buildings, industrial buildings, cultural uses, educational uses, recreational uses, places of public worship, and government/institutional or community uses. Population protected from noise impacts include noise sensitive receivers within 300m from the Project Boundary including residential buildings. Population protected from water quality impacts include water sensitive receivers within 500m from the Project Boundary.