13                     SUMMARY OF ENVIRONMENTAL OUTCOMES

13.1                  Overview

13.1.1.1         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 11 have demonstrated that all the statutory requirements in EIA Study Brief (ESB-343/2021) and EIAO-TM have been compiled with.

13.1.1.2         This chapter 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.

13.2                  Environmental Benefits of the Project

13.2.1.1         The Project is designed to widen individual road sections of the existing TWR with proposed slip road to cope with future traffic demand at individual road sections of TWR and the associated junction along existing TWR. The anticipated improvement of the traffic performance (i.e. relieving potential traffic congestion, smoother traffic flow, etc.) at individual sections of TWR brought about by the Project will alleviate the air quality and noise impacts associated with traffic congestion during peak hours.  While potential noise impact on individual noise sensitive receivers due to the proposed road widening works has been identified, corresponding noise mitigation measures such as noise barriers, noise enclosures and low noise road surfacing will be provided under the Project.

13.3                  Incorporation of Environmentally Friendly Options

13.3.1.1         Avoidance of environmental impacts is one of the main considerations throughout evaluation 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);

·       Minimisation of numbers of piers and foundation works; and

·       Minimisation of number of new highway structures.

Avoidance of conflicting with the existing Old and Valuable Trees (OVTs)

13.3.1.2         None of the registered OVTs will be affected by the Project. All the affected trees are common species with an average of medium to low amenity value.

Minimisation of numbers of piers and foundation works

13.3.1.3         The preferred alignment option and the direct noise mitigation measures to be applied are designed to comprise minimum numbers of piers and foundations. Less excavation works would be involved and hence construction dust and noise impacts to nearby residential premises are minimized. Visual impact is also minimized owing to minimal numbers of new piers.

Minimisation of number of new highway structures

13.3.1.4         Numbers of new slip road viaducts is reduced from five in the Initial Scheme to two in the Preferred Scheme. In addition, the preferred alignment option mainly comprises modification of existing TWR bridge structure. Construction period is minimized and hence the associated environmental nuisance to nearby residential premises is minimized. Visual impact is also minimized owing to minimal number of new highway structures.

13.4                  Environmental Design Recommended

13.4.1.1         Other than initiatives to avoid environmental impacts as summarized in Section 13.3, 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

13.4.1.2         Precast construction method would 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 would be considered only when precast construction method is not feasible.

Implementation of Trip-Ticket System

13.4.1.3         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

13.4.1.4         In addition to the mitigation measures as described above (see more details in the Implementation Schedule of Recommended Mitigation Measures as given in Appendix 12.1), 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.

13.5                  Key Environmental Problems Avoided and Environmentally Sensitive Areas Protected

13.5.1.1         Sections 13.3 and 13.4 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 13.1 presents the key environmental problems that have been avoided and any sensitive areas protected by these approaches.

Table 13.1        Summary of Key Environmental Problems Avoided and Sensitive Areas Protected

Design Approach

Environmental Problems Avoided and Sensitive Areas Protected

Adoption of environmental friendly construction methods

(Section 2)

·       Adoption of offsite precast structures / modular integrated construction method to minimise the impacts on air quality, noise, water quality and waste during construction.

Provision of direct noise mitigation measures

(Section 4)

·       Protection of NSRs through provision of adequate noise mitigation measures during the operation of the Project.

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 12)

·       Ensure all the recommended measures are properly in place and their effectiveness.

13.6                  Environmental Protection Measures Recommended

13.6.1.1         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 13.2 below.

Table 13.2        Key Recommended Mitigation Measures

Environmental Aspect

Mitigation Measure and any Associated Benefit

Air Quality Impact

Construction Phase:

·       Implementation of dust suppression measures as required in the Air Pollution Control (Construction Dust) Regulation to minimize construction dust impact.

·       The approved non-road mobile machinery (NRMMs) under NRMM Regulation (excluding exempted NRMMs) would be used on site and NRMMs supplied with mains electricity instead of diesel-powered should be adopted as far as possible to minimize the potential emission from NRMMs.

 

Operation Phase:

·       No mitigation measures would be required.

 

Noise Impact

Construction Phase:

·       NSRs are protected with implementation of quiet PME, temporary/movable noise 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.

Operation Phase:

·       Low Noise Road Surfacing (refer Appendix 4.9 - Figure 4.5c and Figure 4.5d (“with Slip Road C Option”) for locations and extents):

-        Approx. 205m at Tsing Tsuen Road

·       Proposed Noise Barriers and Enclosures (refer to Figure 4.5a and Figure 4.5b (“without Slip Road C” Option) for locations and extents):

-        Approx. 100m of 6.5m High with 3.5m Cantilever (at 45 degrees) Barrier (N1)

-        Approx. 94m Full-Enclosure (FE1)

-        Approx 177m Full-Enclosure (FE2)

-        Approx. 470m Semi-Enclosure (SE1)

 

·       Additional mitigation measures for “with Slip Road C” Option (refer Appendix 4.9 – Figure 4.5c and Figure 4.5d)

-        Approx 35m of 4.5m High Vertical Barrier (N2)

-        Approx. 270m Semi-Enclosure (SE2)

-        Approx. 70m Semi-Enclosure (SE3)

-        Approx. 500m Semi-Enclosure (SE4)

 

Water Quality Impact

Construction Phase:

·       ProPECC PN 1/94 "Construction Site Drainage" should be followed to minimize construction runoff

·       ETWB TC (Works) No. 5/2005 Protection of natural streams / rivers from adverse impacts arising from construction works should be adopted where applicable to minimise the water quality impacts on any natural streams or surface water systems

Operation Phase:

·       The design of site drainage should follow the relevant guidelines and practices as given in the ProPECC PN 5/93

·       Best Management Practices (BMPs) for storm water discharge are recommended to reduce the stormwater pollution arising from the Project

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.

·       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.

·       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 arising from the Project is anticipated and no mitigation measure is considered necessary.

Landfill Gas Hazard

Routine gas monitoring should be undertaken to mitigate potential risk associated any landfill gas accumulation in newly created excavations during construction or future operational maintenance. Monthly gas monitoring for any offices, stores etc located within areas of the Project location within GDBL and its 250m Consultation Zone during construction should also be undertaken. Provided that the safety requirements stated in Chapter 8 of the Landfill Gas Hazard Assessment Guidance Note are implemented properly, safety of construction and maintenance staff would be safeguarded from potentially adverse landfill gas hazard.

During the operation phase, for maintenance of TWR, resurfacing of other maintenance works will be carried out at open space and any risk from landfill gas are unlikely. Therefore, no special precautionary measures related to landfill gas hazard are required. 

Hazard to Life

According to the latest PHI register, YKTWTW is not considered as a PHI. No hazard to life assessment for liquid chlorine related issue is required for YKTWTW and adverse impact during construction and operation phase not anticipated.

Impact on Cultural Heritage

No impact to cultural heritage would be anticipated from the construction and operation of the Project.   Hence, no mitigation measure would be required.

Landscape and Visual

·       Preservation of existing vegetation.

·       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.

·       Compensatory planting for loss of existing trees to enhance ecological value and improve overall value of landscape setting.

·       Landscape reinstatement and treatment on slopes to maximize the greening provision along the road improvement works.

·       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 carriageways and other highway structures to minimise any potential adverse landscape and visual impact.

13.7                  Estimation of Population Protected

13.7.1.1         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 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, educational uses, recreational uses, and government/institutional or community uses.  Population protected from noise impacts include noise sensitive receivers within 300m from the Project Boundary including residential buildings and the estimated total number of existing dwellings that will be protected by the project is 859.