16               Conclusion

16.1                   General

16.1.1              An EIA Report has been prepared for the development of San Hang Road and Hong Po Road in accordance with the requirements given in the EIA Study Brief (ESB-299/2017) and the EIAO-TM. Environmental assessment of the potential environmental impacts associated with the construction and operation of the Project has been conducted. Environmental issues covered in the EIA include:

·            Air quality impact;

·            Noise impact;

·            Water quality;

·            Sewage and sewerage treatment implications;

·            Ecology impact;

·            Impact from Electric and Magnetic Fields;

·            Landscape and visual impact;

·            Waste;

·            Land contamination; and

·            Cultural heritage.

16.1.2              This section summarises the assessment results of each technical aspect and concludes the acceptability of the overall environmental performance of the Project.

16.1.3              The key assessment assumptions, limitation of assessment methodologies and all related prior agreements with EPD on assessment of different environmental aspects are given in Appendix 16.1.

16.1.4              A summary of environmental impacts identified in this EIA is provided in Appendix 16.2 and the conclusions of technical chapters are described in the following sections.

16.2                   Air Quality Impact

Construction Phase Impact

16.2.1              Potential air quality impacts from the construction works of the Project would mainly be related to construction dust from excavation, materials handling, spoil disposal and wind erosion. Quantitative fugitive dust assessments have been conducted, taking into account the cumulative impact caused by nearby concurrent sources within 500 m from the boundary of the Project Site. With the implementation of hourly watering at the active works areas, exposed areas and unpaved haul roads and other site management measures such as, good site practices, and environmental monitoring and audit (EM&A) programme, the predicted Total Suspended Solid (TSP), Respiratory Suspended Solid (RSP) and Fine Suspended Solid (FSP)  at representative air sensitive receivers (ASRs) would comply with the criteria stipulated in the Air Quality Objectives (AQOs) and EIAO-TM.

Operation Phase Impact

16.2.2              Key existing and planned/committed air pollution sources during operation phase are the vehicular emissions from open sections of existing roads, proposed roads and proposed junction improvements within the assessment area. Cumulative air quality impact at the representative ASRs would also be expected due to the background pollutant concentrations, portal emissions from the noise enclosure at Tsing Lun Road and industrial emissions from the identified chimneys within the assessment area as well as the emissions from the asphalt plant at Lam Tei Quarry outside the assessment area. Key representative air pollutants include Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), RSP and FSP. Quantitative assessment has been conducted and the assessment results concluded that the predicted cumulative air quality impacts with full population intake on all ASRs would comply with the AQOs. Therefore, no adverse air quality impact during operation phase is anticipated.

16.2.3              With the installation of deodourising units with 99.5% odour removal efficiency and appropriate design measures at the proposed SHR SPS, it is anticipated that there would be no adverse odour impact from the proposed SHR SPS at the nearby ASRs. 

16.3                   Noise Impact

Construction Noise Impact

16.3.1              Construction noise associated with the use of PME for different stages of construction has been conducted. With the implementation of quieter construction method and practical mitigation measures including good site management practices, use of QPME, use of movable noise barrier, noise enclosure and noise insulating fabric, construction noise impacts at all of the neighbouring residential noise sensitive uses and educational institutions during normal school period would be controlled to acceptable levels. Minimum separation distance between schools and critical works area during school examination period have been recommended to mitigate potential adverse construction noise impact during examination period. With the recommended mitigation measures in place, construction noise impacts on all representative NSRs would comply with the relevant criteria. In case of any construction activities during restricted hours, it is the Contractor’s responsibility to ensure compliance with the Noise Control Ordinance (NCO) and the relevant TMs. The Contractor will be required to submit a construction noise permit (CNP) application to the Noise Control Authority and abide by any conditions stated in the CNP, should one be issued. It should be noted that description made in this report does not guarantee that a CNP will be granted for the project construction. The Noise Control Authority would take into account the contemporary conditions of adjoining land uses and other considerations when processing the CNP application based on the NCO and relevant TM issued under the NCO. The findings in the report shall not bind the Noise Control Authority in making the decision.

Road Traffic Noise Impact

16.3.2              Operation road traffic noise impact on the representative existing and planned noise sensitive uses within and near the PDA and the junction improvement works have been predicted.  To mitigate the road traffic noise impact on the existing and planned NSRs within and near the PDA and near the junction improvement at J13, a combination of noise mitigation measures have been recommended, including i) application of low noise road surfacing material along some sections of Project roads and other roads, ii) road side noise barriers along some sections of Project roads, iii) provision of acoustic windows for the public housing and iv) housing site boundary wall for the Welfare Facilities and vi) restriction on locating the more noise sensitive welfare uses at façade facing the realigned Hong Po Road and access road in HPR Site.  With the implementation of mitigation measures, the predicted traffic noise levels of the existing NSRs and planned NSRs would comply with the relevant criteria or the noise contribution from Project road is <1.0 dB(A).  For junction improvement works, the traffic noise levels at the existing and planned NSRs near the junctions, except junction J13, would comply with the relevant criteria or the change of noise level is insignificant. Direct mitigation measures for J13 and mitigation measures at Tuen Mun Area 54 Site 5 have been recommended.  With the implementation of mitigation measures, the predicted traffic noise levels of the NSRs near J13 would comply with the relevant criteria.

16.3.3              The proposed mitigation measures at the proposed housing sites (i.e. the provision of acoustic windows for some planned public housing and housing site boundary wall near the Welfare Facilities and restriction of certain type of welfare uses at some facades) are made known to HKHA and subject to further study by the HKHA. HKHA can further explore alternative options which can achieve corresponding traffic noise reduction during the detailed design stage. An Environmental Assessment Study for the planned public housings will be conducted by HKHA in the detailed design stage to address environment impacts and to comply with relevant criteria. 

Fixed Noise Source Impact

16.3.4              Fixed noise source impact assessment has been conducted for all existing and planned fixed noise sources. Noise impact from planned fixed plant could be effectively mitigated by implementing noise mitigation measure at source. With the adoption of the proposed maximum permissible SWLs of the ventilation fans for the proposed PTIs, the impact noise levels at the representative NSRs would comply with the relevant noise criteria for both existing and planned fixed noise sources. The PTIs will be enclosed and designed to avoid direct line-of-sight to the NSRs. Therefore, adverse fixed noise sources impact on the NSRs is not anticipated.  The design of the PTIs and the proposed maximum permissible SWLs of the ventilation fans shall be reviewed with the final design during the detailed design stage.

Rail Noise Impact

16.3.5              Rail noise impact assessment has been conducted for the planned NSRs at the SHR Site potentially affected by the WRL and LRT operation.  With the implementation of mitigation measure in the form of provision of acoustic windows, the impact noise levels at all representative NSRs would comply with the relevant rail noise criteria. Therefore, adverse rail noise impact on the planned NSRs is not anticipated. HKHA can further explore alternative options which can achieve corresponding rail noise reduction during the detailed design stage. An Environmental Assessment Study for the planned public housings will be conducted by HKHA in the detailed design stage to address environment impacts and to comply with relevant criteria.

16.4                   Water Quality

Construction Phase

16.4.1              With proper implementation of all the recommended mitigation measures, proper site management and good site practices, there would be no unacceptable water quality impact from surface runoff of the construction site and sewage generated from construction workforce.

Operation Phase

16.4.2              Sewage discharged from the proposed development will be collected by the proposed sewage pipes leading to the SHR SPS and downstream sewerage network and Pillar Point Sewage Treatment Work (PPSTW) for treatment.  No adverse water quality impact is expected.

16.4.3              Contingency measures for the proposed SHR SPS such as a storage tank, twin rising mains, standby pumps, and dual electricity supply or backup power supply facilities should be adopted to prevent emergency situation as far as practical.

16.4.4              There would be no residual water quality impact during both construction and operation phases of the Project.

16.5                   Sewage and Sewerage Treatment Implications

16.5.1              The proposed SHR SPS would collect sewage from SHR Site, SHR Site Extension and HPR Site for conveyance to the downstream sewerage system. During the construction phase, impact on the existing sewerage system arising from the Project is not anticipated.

16.5.2              New public sewerage system is proposed in the PDA to collect the sewage generated from the proposed development in the PDA. A new SPS will be constructed at SHR Site to collect sewage generated from SHR Site, SHR Site Extension and HPR Site and convey to the downstream sewerage system. The PPSTW would have adequate treatment capacity to cater for the sewage flow generated from the PDA and developments in Area 54, Tuen Mun. Based on the findings of this sewerage and sewage treatment impact assessment, the Project is sustainable from sewage collection, treatment and disposal perspective.


 

16.6                   Ecology Impact

16.6.1              Ecological baseline was established by both literature review and 8 months programme of field surveys covering both dry and wet seasons.  A total of 11 types of habitat were identified within the ecological assessment area, of which 8 types of habitats, including woodland, agricultural land, natural stream, semi-natural stream, drainage channel, village/orchard, village area and urban area were located within the Project Site where the development area and associated infrastructure works are proposed.

16.6.2              Avoidance measures were considered and incorporated during early stages of the Project. Direct encroachment onto the two identified sites of conservation interest namely a mature secondary woodland W2 near Tong Hang Road and the Conservation Area (CA) zone of near Chung Shan within the assessment area has been avoided by the Project. An upstream section of the semi-natural stream (R1f) at HPR Site is proposed to be retained by adjusting the project site boundary for the preservation of the localities of two crab species of conservation interest (Cryptopotamon anacoluthon and Somanniathelphusa zanklon). 

16.6.3              Most habitats to be lost, such as agricultural land, drainage channel, village area, village/orchard and urban area are of low ecological value. Although the overall habitat quality of the concerned woodland is rated medium ecological value, the affected portion is a low-quality habitat patch, and regularly disturbed by grave-sweeping activities. Hence, the potential impact due to loss of woodland is minor. The potential impacts due to loss of habitats are all considered minor or insubstantial.

16.6.4              Consideration of avoiding the impacts on floral species of conservation interest Aquilaria sinensis and Pyrenaria spectabilis has been taken into account during the selection of the alignment and construction method of the proposed Road L7 at Po Tong Ha. With careful designation of the alignment and the adoption of suitable construction method for the retaining structures along the proposed Road L7, all the Pyrenaria spectabilis and majority of Aquilaria sinensis can be preserved in-situ without any conflicts with the proposed works. Only three individuals of Aquilaria sinensis were found falling within the footprint of the proposed Road L7. To minimize the impact on the three individuals of Aquilaria sinensis, two of them will be preserved by transplanting while the remaining one will be felled down due to its extremely poor health condition. With implementation of proposed mitigation measure, the impact on Aquilaria sinensis is insubstantial.

16.6.5              Majority of the recorded localities of the two crab species of conservation interest Cryptopotamon anacoluthon and Somanniathelphusa zanklon are identified at the semi-natural stream section of R1f marginally located along the boundary of HPR Site. To avoid the direct impact, the ecologically sensitive upper section of the semi-natural stream located in HPR Site is proposed to be retained by excluding from the project site area. After this active avoidance measures, only one locality of Cryptopotamon anacoluthon will be unavoidably affected due to the permanent loss of its habitats for the development. Translocation of these crabs are recommended at suitable undisturbed stream habitat before construction. With the implementation of the recommended translocation measure and recommended good site practices (e.g. Use of quiet mechanical plant and regular dust suppression measures, etc), no significant overall ecological impact on the crab species is anticipated. To further improve the carrying capability of the semi-natural stream for the two crab species of conservation interest, ecological enhancement for the retained section of the semi-natural stream by reinstating its artificial bank structure to natural riparian habitat and provision of 6m buffer distance along the retained section is proposed. 

16.6.6              Though the impact of woodland loss at W3 is anticipated to be minor due to limited affected size and low-quality of the affected woodland patch, provision of woodland enhancement planting is recommended to enhance the ecological performance of the area. According to the current proposal, enhancement planting of not less than 1.2ha will be provided.

16.6.7              With the implementation of the recommended mitigation measures, no adverse residual ecological impacts arising from the implementation of the proposed Project are anticipated.

16.7                   Impact from Electric and Magnetic Fields

16.7.1              Some sections of the existing 400kV overhead cables run across the Hong Po Road and San Hing Tsuen areas, in order to investigate the potential health hazard to humans due to exposure to electric field (ELF) and magnetic field (EMF) generated by overhead lines. On-site measurement has been conducted at the selected locations which represent the proposed locations of PTIs, housing development areas, school sites and SPS.

16.7.2              The assessment results confirmed that the strength of the ELF and EMF generated from the 400kV overhead cables are well below the stipulated guideline limits issued by the ICNIRP in 1998.  Thus. the ELF and EMF generated by overhead cables will not pose a hazard to human health.

16.8                   Landscape and Visual Impact

Landscape Impacts

16.8.1              Total eight (8) LRs, three (3) broad LCAs and fourteen (14) VSRs were identified within the Assessment Area. The Project will inevitably result in some landscape impact and significance threshold during construction and operation phases. The existing village/low-rise character would be transformed into a more urbanized landscape setting after commissioning of the Project. It is not possible to fully mitigate all landscape impacts in relation to loss of natural/semi-natural stream, hillside woodland, agricultural land or orchard for affected LRs and LCAs in the construction period and early operation stage, mainly as long periods of time are required to sufficiently compensate for the associated impacts. A broad-brush tree survey has been carried out, it is found that four (4) numbers of tree of particular interest (including 2 nos. of Ficus microcarpa, 1 no. of Melaleuca cajuputi subsp. cumingiana and 1 no. of Litchi chinensis) are in direct conflict with the footprint of the Project Site. No Old and Valuable Tree (OVT) was found within the project site boundary or assessment area.

16.8.2              The main impact for the affected LRs (except natural/semi-natural streams) and LCAs would be the loss of greenery and existing trees. Approximately 1,300 nos. of existing trees will be affected during to the Project. To compensate the loss of greenery, not less than 1,300 nos. of new trees in different sizes is proposed to be planted as far as practicable. Existing trees will be preserved as far as practicable. If retained trees are not practicable, transplantation of the affected trees to other suitable locations within the project sites or the adjacent areas will be considered. Tree removal will only be considered when tree preservation or transplantation is found unsuitable or impracticable. Tree Preservation and Removal Proposal will be prepared during detailed design stage, to finalise tree treatment and allocate compensatory planting areas including open space, sitting out areas and streetscape.

16.8.3              With implementation, the proposed mitigation measures such as compensatory planting, tree protection and preservation, tree transplantation, roads greening, screen planting and enhancement of natural/semi-natural stream etc. The residual impacts to LRs and LCAs can be reduced to an acceptable level.  

Visual Impacts

Construction Phase

16.8.4              Visual impacts are primarily due to the high-rise development but also due to the construction of proposed road system, proposed SPS, water services reservoirs and natural terrain. In addition, visual impact will also involve the impacts from excavation works, site formation works including for man-made slopes, works areas, traffic diversions and obstruction of views due to hoarding, as well as the loss of greenery due to the removal of trees and vegetation. All of the Visual Sensitive Receivers (VSRs) are affected by the Project in different levels. Visual blockage would be gradually built-up by phase as a continuous process. While impact arising from the construction works at lower level are limited, the views are partially screened by adjacent architectures, existing vegetation and level difference of landforms. With the implementation of proposed mitigation measures such as site hoarding and control of night-time glare, the visual impact during construction will be mitigated. 

Operation Phase

16.8.5              From visual perspective, considering the large-scale public housing estate on the sites above building platform, the proposed development would inevitably create building mass and site formation that would induce major significance threshold to the village setting. The carpark users in Tuen Tsz Wai and the residents in Po Tong Ha are anticipated to experience substantial visual impacts. On the other hand, a number of VSRs are anticipated to experience moderate visual impacts, including: the passengers on the train heading towards MTR Siu Hong Station of the West Rail Line, road users at Hong Po Road roundabout and the hikers  walkalong the trails between Castle Peak and Por Lo Shan, the visitor of Miu Fat monastery and the visitors for tomb-sweeping around Chung Shan hillsides. Rest of the VSRs would experience slight visual impacts.

16.8.6              The project design has endeavoured every effort to minimise potential impacts to practical minimum. The placement of housing blocks has taken into consideration of the permeability of views, trying to allow for gaps between buildings to maximize views between the buildings rather than create a solid blockage of views. The proposed light control helps to avoid light and glare disturbance. Broad coverage of planting is efficient to compensate the loss of greenery which would further enhance the visual condition in local context of the development sites. Slope and screening planting would provide additional greenery, buffering offsite environments. Detailed Design Measures are suggested in order to improve façade treatment of built structures, providing better visual impression to public. The above measures are feasible to minimize the visual disturbance to public viewers as practical.

16.8.7              In summary, upon mitigation measures of operation year 10, impacts to 7 nos. of VSRs (2, 3, 4, 5, 8, 10 & 14) are slightly adverse, 5 nos. of VSRs (7, 9, 11, 12 & 13) are moderately adverse and 2 nos. of VSRs (1 & 6) are substantially adverse. The overall quality of existing VSRs will be moderately adverse, particularly to village or low-rise residential area adjacent to periphery of the development, given that the scale and nature of project is relatively large with high-rise residential blocks. While other residential area with sufficient distance to the project, the proposed blocks would visually merge within high-rise urban development at east and south side of the site, which in general be slight adverse. Therefore, given sufficient time for well-implemented measures and maturity for planting measures, as well as design consideration, the project will not create significant disturbance to general viewing experience and could be integrated to existing environment.   

16.8.8              For the DP1, which is the proposed SPS at SHR Site, in view of the small scale of development, no significant landscape impacts on LRs and LCAs, as well as visual impacts on VSRs are anticipated. 

16.8.9              Overall, there will be some adverse effects brought up by the Project, mitigation measures have been proposed and the project design has endeavoured every effort to minimise potential impacts to practical minimum. Assuming that full and appropriate mitigation measures are to be implemented during construction and operation phases, the residual landscape and visual impacts are perceived to be acceptable with mitigation measures, as stated in EIAO-TMs and EIAO Guidance Note No. 8/2010.

16.9                   Waste Management

Construction Phase

16.9.1              The main waste types to be generated during the construction phase of the Project would include construction and demolition (C&D) materials, chemical waste, general refuse and asbestos containing material (ACM). Reduction measures have been recommended to minimise the amount of materials generated by the Project by reusing C&D materials as far as practicable before off-site disposal.

16.9.2              The inert C&D materials generated from the Project will be reused within the Project or other concurrent projects as far as practical. For instance, during site clearance and site formation works, it is assumed that around 68% of the inert C&D materials will be suitable for reuse on-site as backfilling materials under this Project and the rest of inert C&D materials (about 184,000 m3) will be transported to other concurrent projects and/or public fill area (Tuen Mun Area 38 Fill Bank) for reuse. Temporary stockpiling areas are also identified to store the C&D materials to be reused under this Project. Provided that the waste is handled, transported and disposed of using approved methods, adverse environmental impacts would not be expected.

Operation Phase

16.9.3              The main types of waste to be generated during the operation phase of the Project would consist of municipal solid waste (MSW), screenings and chemical waste. It is expected that the Project would generate around 150 tonnes of MSW per day in total, about 3.5 m3 of screenings per week, and a minimal amount of chemical waste, mainly from maintenance activities on the road networks and the SPS within the proposed development sites. The MSW generated would be diverted to refuse collection points before being transported to the existing West New Territories (WENT) Landfill outside the PDA. Initiatives such as promoting recycling and providing recycling bins would be employed in order to minimise the amount of MSW to be disposed of at landfill. Provided that the waste generated in the operation phase is handled, transported and disposed of properly, no adverse environmental impacts are anticipated.

16.10              Land Contamination

16.10.1          This land contamination assessment examined the potentially contaminated land uses within the Project Site, including the PDA and the works area for the associated infrastructure.  Site appraisal comprises site walkover, review of historical aerial photographs and maps, review of historical spillage and leakage records and review of previous intrusive site investigation was undertaken at the Project Site.

16.10.2          Based on the current information, 57 potential contaminated sites have been identified within the Assessment Area.  Based on the site survey and desktop review, the majority of the sites have been identified as open storage, container yards, rural workshops and service yards. These potentially contaminated sites are not large-scale pollution installations/facilities such as oil depots and power plants. The source of potential land contaminating activities at the identified sites mainly relates to the spillage and accidents associated with the storage and use of chemicals. As such, it is considered that if there is indeed any land contamination present at these sites, it is expected that it would be localized. 

16.10.3          The chemicals of concern (COCs) identified at the potentially contaminated sites include VOCs, SVOCs, Metals, PCRs, PCBs, etc. These COCs are readily treatable with proven remediation techniques in local remediation experience, e.g. decontamination works at the Cheoy Lee Shipyard. By implementing the recommended remediation works, any contaminated site (s) identified within the assessment area could be cleaned up prior to construction/development.   The contamination problem in the land uses that are identified as potentially contaminated would not be considered insurmountable in the supportive view that any contaminated soil should be remediated by the Project Proponent.

16.10.4          The recommended remediation works would not only minimise the health risk to the future occupants arising from the exposure of the contaminated soil and/or groundwater, it would also provide the opportunity to reuse the contaminated materials into useful materials for backfilling, which results in minimising the amount of waste disposing into the depleting landfill in Hong Kong and achieving a more sustainable development.

16.10.5          Since the potentially contaminated sites are located in operation, SI is unlikely to be carried out at this stage. There may be change in land use prior to development within both the potentially contaminated and other surveyed sites.  In view of this, further site visits to these potentially contaminated sites are proposed once future development of these sites is confirmed and that site access is available in order to identify the need for SI for any additional hot spots as a result of the on-going land contaminating activities. In addition, re-appraisal would be required for areas within the Project Site to address any change in land use that may give rise to potential land contamination issues. 

16.10.6          Findings from the re-appraisal will be presented in a supplementary Contamination Assessment Plan(s) (CAP(s)). Upon approval of the supplementary CAP(s) and completion of the SI works, a Contamination Assessment Report(s) (CAR(s)) would be prepared to present findings of the SI works. If contamination has been identified, Remediation Action Plan(s) (RAP(s)) would be prepared to recommend specific remediation measures. Upon completion of the remediation works, if any, Remediation Report(s) (RR(s)) would also be prepared to demonstrate that the clean-up works are adequate. The CAR(s), RAP(s) and RR(s) would be submitted to EPD for approval prior to commencement of any construction / development works.

16.11              Cultural Heritage

Archaeology

16.11.1          The Project Site’s proposed development areas are located within or in very close proximity to San Hing Tsuen, Siu Hang Tsuen, and Kei Lun Wai SAIs. The evaluation of the previous findings indicated that the part of the proposed development located at northern part of Area 2 (within the San Hing Tsuen SAI) which may be adversely affected. It is recommended that prior to the commencement of any construction works, a programme of Archaeological Field Survey should be implemented for the development in northern part of SHR Site (Area 2 – See Section 13.6 of EIA Report) upon land resumption and clearance of structures and prior to construction phase. This will identify if significant deposits or features are present and follow up action can be recommended. Field works will have to be conducted after land resumption and clearance of structures. Archaeological Action Plan (AAP) which shall be submitted by the qualified archaeologist appointed by the project proponent The field evaluation will identify if significant deposits or features are present and if further mitigation is required and prepared by a qualified archaeologist for AMO agreement.

16.11.2          For the areas with low or no archaeological potential, works should cease and AMO should be informed immediately in case of discovery of antiquities or supposed antiquities in the course of the construction works. Agreement from AMO would be sought on the follow-up actions if required.

Built Heritage

16.11.3          Literature review is conducted to collate relevant information on Declared Monuments and Graded Historical Buildings. Previous investigations under other projects (See Section 13.4 of EIA report) within the current study area and surrounding area indicate little potential for built heritage or heritage as identified in Guidelines for Cultural Heritage Impact Assessment and as such no further built heritage survey was deemed necessary. There are no proposed or declared monuments, graded or proposed to be graded historic buildings, Government historic sites or new items proposed for grading by the Antiquities Advisory Board (AAB) within the PDA. In summary it can be stated that no built heritage will be affected during construction and operation phases of the project with the proposed developments.

16.12              Environmental Monitoring and Audit Requirements

16.12.1          It is recommended to implement an EM&A programme to monitor the environmental impacts on the neighbouring sensitive receivers regularly. An EM&A Manual is  prepared to specify the monitoring requirements, timeframe and responsibilities for the implementation of the environmental mitigation measures identified in the EIA report. An Environmental Mitigation Implementation Scheme as stated in the EIA report and EM&A Manual has summarised all the measures, the implementation locations, timeframe, agency etc. and required to strictly follow.

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