13 Conclusions

13.1 Conclusion of EIA Study

13.1.1.1 This EIA Report has provided an assessment of the potential environmental impacts associated with the construction and operation of the Project, based on the engineering design information available during the course of EIA study.

13.1.1.2 The assessment has been conducted, in accordance with EIAO-TM, covering the following environmental issues:

· Air Quality Impact

· Noise Impact

· Water Quality Impact

· Waste Management Implications

· Land Contamination

· Ecological Impact (Terrestrial)

· Landscape and Visual Impact

· Impact on Cultural Heritage

13.1.1.3 The findings of this EIA study have determined the likely nature and extent of environmental impacts predicted to arise from the construction and operation of the Project. During the EIA process, environmental control measures have been identified and incorporated into the planning and design of the Project, to achieve compliance with environmental legislation and standards during both the construction and operation phases. The Implementation Schedule listing the recommended mitigation measures is presented in Appendix 11.1.

13.1.1.4 With the implementation of the mitigation measures, the Project would be environmentally acceptable with no unacceptable residual impacts on the environmentally sensitive receivers and resources. Table 13.1 below summarizes the key environmental outcomes and benefits that have accrued from the environmental considerations and analysis during the EIA process and the implementation of environmental control measures of the Project. Appendix 13.1 presents the summary of key assessment assumptions, limitation of assessment methodologies and related prior agreements with the Director and Appendix 13.2 presents the summary of environmental impacts.

13.1.1.5 The various sections of this EIA Report have presented the measures to minimize the potential environmental impacts associated with the Project throughout the construction and operational phases. The key measures to minimize the environmental impacts are summarized in Section 12.

13.1.1.6 An Environmental Monitoring and Audit (EM&A) programme has been developed to ascertain and verify the assumptions implicit to, and accuracy of, EIA study predictions. EM&A requirements have been recommended, where necessary, to check on project compliance of environmental legislation and standards. These are presented in a separate stand-alone EM&A manual.

Table 13.1 Summary of Key Environmental Outcomes and Benefits

Environmental Issue	Description
Environmental / Social Benefits of the Project	· Eastbound alignment shifted away from Tung Lo Wan Village and residential buildings of Sha Tin Central and placed in front of Tai Wai industrial buildings, less noise and quality impacts to the residents of the buildings close to the bridges during operation stage. · Depressed road / underpass sections at the south of Shing Mun River Channel (SMRC) reduces the air quality and noise impact to the residents of Sha Tin Tau Village (STTV) and Tsang Tai Uk Village (TTUV) during operation stage. · Avoid conflicting with existing Old and Valuable Trees (OVTs) along Chung Ling Road · Eastbound alignment shifted away from Tung Lo Wan Village and residential buildings in Sha Tin Central with less visual impact. · Depressed road / underpass sections at the south of SMRC would have insignificant visual impact during operation stage, particularly for the residents of the Riverpark, STTV and TTUV and Fung Shing Court. · Additional road connections between the T4 and local road network in Sha Tin Central which help to relieve traffic congestion in Sha Tin Central and provide convenience to road users.
Environmentally Friendly Design and Options	· The operation traffic noise from existing at-grade roads, e.g. Lion Rock Tunnel Rock is identified to be the main source of nuisance to the nearby NSRs of residential buildings in Sha Tin Central, application of advance low noise road surfacing (LNRS) to the carriageways of the existing at-grade roads to reduce the traffic noise is recommended. · No noise semi-enclosure will be required to be installed on the bridge structures of the T4 fronting the HKHM with the application of the advance LNRS on existing roads and LNRS at new roads, the visual impact to the LCA of the Hong Kong Heritage Museum (HKHM) and nearby residents is reduced. · No noise barrier/enclosure is proposed to be erected on the northern portion of the T4 bridge deck across SMRC within the flight path of ardeids to avoid bird collision. · Avoid having ventilation buildings/shafts for the underpasses, large size openings will be provided on the rooftop of the two underpasses at STTV to adopt natural ventilation. · Avoid significant environmental and ecological impacts to the habitats of the Lion Rock Country Park (LCRP), the proposed soil nailing works within LRCP will be replaced by a rigid barrier to be erected at the edge of the widened Sha Tin Road (outside the boundary of LRCP). · Recommend to adopt precast concrete construction method for construction of viaduct which is a more environmentally friendly approach. · Implementation of Environmental Monitoring and Auditing System.
Air Quality Impact	Construction Phase: · Potential dust impact generated from construction activities, such as site clearance, utilities protection and diversion works, slope work, excavation, piling and roadworks, and wind erosion of exposed work area, and emission from PMEs would be minor. With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation together with the recommended dust suppression measures and good site practices, no adverse dust impact at ASRs is anticipated due to the construction activities of the Project. Operation Phase: · Cumulative air quality impact arising from the operation of the Revised Trunk Road T4 such as vehicular emission from open roads and nearby chimneys within 500 m study area has been assessed for the operation phase of the Project. The results conclude that the predicted cumulative NO₂, RSP and FSP concentration at all ASRs would comply with AQOs. No adverse air quality impact is anticipated arising from the operation of the revised Trunk Road T4.
Noise Impact	Construction Phase · The NSRs are protected with the implementation of quiet PME, movable barriers and full enclosure as well as good site practices during construction phase. The predicted mitigation noise levels comply with the noise standards at all NSRs 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 · Although there is still predicted exceedance of the noise criteria at some of the NSRs under the mitigated scenario, with the implementation of noise mitigation measures including LNRS, vertical noise barriers/cantilever noise barriers and semi/ full enclosures on some Project roads, the exceedances were dominantly contributed by the nearby existing roads. The contributions from the Project roads at all NSRs are less than 1.0 dB(A) and the predicted noise levels at NSRs due to the Project roads would comply with the noise criteria. Thus, no adverse road traffic noise impacts arising from the Project would be anticipated. · The Project itself is not a fixed noise source. No fixed noise impact would arise from the Project.
Water Quality Impact	Construction Phase: · The construction of bridge structures across Shing Mun River Channel would require the installation of new bridge piers in Shing Mun Main River. The excavation and pilling works will only be carried out in a confined dry working environment by phases and only one cofferdam would be installed in each period. With implementation of mitigation measures including installation of watertight steel casing and cofferdam at the pier site, provision of appropriate desilting or sedimentation device for treatment of water from dewatering process and deployment of silt curtains for construction works, no unacceptable water quality impact was expected due to construction of the bridge piers. · Besides, the construction activities would be conducted by phases and only one cofferdam would be installed in each period. With consideration of the cross-section area of the rive channel to be blocked by the pier installation, no unacceptable impact on hydrodynamic of Shing Mun River was anticipated. · Excavation and construction works for the diversion of Sha Tin Tau Nullah have potential to create water quality impact at the downstream area if unmitigated. As such, the nullah diversion works should be scheduled in dry season as far as practicable when the flow is low. Temporary drainage or permanent drainage at most downstream should first be established to intercept and divert the upstream flow. Good site practices as described in ETWB TC(Works) No. 5/2005 “Protection of natural streams/rivers from adverse impacts arising from construction works” and ProPECC PN1/94 “Construction Site Drainage” should be adopted where applicable to avoid adverse water quality impact from arising. · Potential water quality impacts from the land-based construction works are associated with the general construction activities, construction site run-off, accidental spillage, and sewage effluent from construction workforce. With implementation of site practices as outlined in ProPECC Note PN 1/94, no adverse water quality impact was expected due to the land-based construction works. Operation Phase: · Potential hydrodynamic impact due to the presence of the permanent bridge pier structure in Shing Mun River was predicted to be localised and transient with consideration of the cross-section area of the river channel to be blocked by the pier. No unacceptable change in flow regime at the river channel was anticipated. · Surface runoff generated from the additional paved areas was identified as an alternate source of potential water quality impact. The associated water quality impact was expected to be minimal and acceptable, provided that the recommended mitigation measures for the drainage system are properly implemented.
Waste Management Implications	Construction Phase: · Waste types generated by the construction of this Project are likely to include C&D materials, chemical waste from maintenance of construction plant and equipment, general refuse and excavated sediment. Provided that these wastes are handled, transported and disposed of according to the recommended good site practices, adverse environmental impacts are not expected. · The excavated sediment generated from the project comprised of marine-based sediment. The excavated marine-based sediment will be treated using S/S technique and will be reused on site (e.g. as backfilling materials). No adverse environment impacts would be expected from the excavation and handling of sediment. Operation Phase: · It is expected that no waste will be generated during the operational phase of the Project. As such it is considered that there should be no adverse environmental impacts.
Land Contamination	· Based on the findings of the site appraisal, no adverse land contamination impact arising from Project is anticipated.
Ecology (Terrestrial)	Construction Phase: · No direct impact to the ardeid night roost site between HKHM and Man Lai Court. · Over 58% of the proposed works areas are situated within developed area along/near the existing roads. · Only very small area of woodland (about 13 m²) and mixed woodland (about 153 m²) within LRCP would be affected by the potential slope stabilization works (flexible barrier). The extent of flexible barrier should be carefully designed to avoid or minimized the potential ecological impacts (e.g. tree felling, impact to flora species of conservation) as far as possible. · For the two flora species of conservation importance (Butulang Canthium and Ailanthus) recorded with 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) recorded in the vicinity of the Project footprint, a detailed vegetation survey should be conducted at the potentially impacted area to ascertain the presence and condition of the above species prior to site clearance. A Plant Preservation and Transplantation Proposal should be prepared and submitted to AFCD for approval to recommend suitable mitigation measures on flora species of conservation importance recorded within and near the Project footprint, including both within LRCP and outside LRCP. · Some low-flying ardeids may be affected by the proposed dual 2-lane flyover near HKHM. However, studies suggested ardeids could adapt and alter their flight paths and flight height to avoid direct collision with physical barrier (e.g. bridge, buildings). No semi-enclosure is proposed at the northern part of proposed flyovers near HKHM. The height of the proposed semi-enclosure at Riverpark side has been carefully designed to minimize the disturbance on the bird flight paths as far as possible to minimize any potential disturbance. · 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. · With the implementation of the recommended mitigation measures, no unacceptable ecological impacts are anticipated during construction phase. Operation Phase: · With the implementation of the recommended mitigation measures, no unacceptable ecological impacts are anticipated during operation phase .
Landscape and Visual Impacts	Construction Phase: · There are 6 nos. of registered OVTs in the vicinity of the project boundary will be retained in-situ and not be affected by the Project. · Based on the broad-brush tree estimate with approximately 3,685 nos. of trees including 176 nos. of trees of particular interest surveyed, approximate 1,051 nos. of existing trees including 13 nos. of trees of particular interest will be unavoidably affected by the Project. · One tree of particular interest Ficus benjamina with high amenity value and large size outside the Hong Kong Heritage Museum will be unavoidably affected and tree transplanting is proposed, subject to the review on technical feasibility and sensitivity analysis in detail design stage and further advice from the existing and future tree maintenance departments. · For the remaining approximate 1,050 nos. of affected trees, tree felling will be proposed. · With implementation of mitigation measures during construction phase, the residual landscape and visual impact is acceptable. Operation Phase: · A minimum of 250 heavy standard trees will be proposed at roadside flat areas, at the re-provided Sha Tin Tau Village Sitting-out Area and at the planting areas of elevated roads with shade-tolerant tree species. · Total area of approximate 11,300m2 will be proposed as compensatory woodland mix planting with approximately 3,400 nos. of tree whips to be planted. · With mitigation measures implemented during operation phases, the residual landscape impacts would be further reduced to insubstantial when the proposed compensatory planting, buffer planting and woodland mix planting become mature in year 10 of operation. · For those VSRs (i.e. R-03, I-03, I-04 and O-01) viewing to the proposed bridge with noise semi-enclosure at Shing Mun River Channel of VP3, VP4 and VP11, and the two VSRs (i.e. R-05 and T-06) viewing to the full noise enclosure along Sha Tin Road of VP8, there are still slight residual visual impacts upon day 1 of operation and year 10 of operation. · There would be insubstantial residual impact on other VSRs within the visual envelope during operation of the Project. In sum, it is considered that the residual landscape and visual impact is acceptable with mitigation measures implemented during operation phases.
Impact on Cultural Heritage	Construction Phase: · Potential direct impacts due to damages through contacting with heavy construction machineries and site negligence would be anticipated for Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage, Ng Yuen, and OLD26. Indirect impacts including ground-borne vibration, tilting and settlement, would be anticipated for Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage, Lau Ancestral Hall, Ng Yuen, High Rock Christian Camp, No. 1, 2 and 3 First Street, OLD1, OLD9, OLD11-21, OLD26-28. · Pre and post condition survey of Tsang Tai Uk, Gatehouse of Pok Ngar Villa, Li Cottage and Ng Yuen. · 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, No. 1, 2 and 3 First Street, OLD1, OLD9, OLD11-21, OLD26-28. · To ensure the stability of historic buildings, foundation information of the historic buildings 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. · Buffer zones with physical barriers should be employed for Tsang Tai Uk, the Gatehouse of Pok Ngar Villa, and OLD26. Substantial physical barriers, such as hoarding or water-filled barriers, should be set up between the project site and each of the two built heritage resources, Li Cottage, Ng Yuen, OLD26. · 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. · With the implementation of mitigation measures, impact on cultural heritage would be acceptable. · No archaeological impact would be anticipated. Thus, no mitigation measure would be required. Operation Phase: · No impact to cultural heritage would be anticipated from the operation of the Project. Hence, no mitigation measure would be required for the operation phase.