1                    iNTRODUCTION

 

Background to the Study

 

1.1              In 1999, Lok Ma Chau Crossing carried an average daily flow of 18,000 vehicles (two-way). Based on the Crosslinks Further Study and the assessment of Transport Department, the total cross-boundary traffic is predicted to increase at an average rate of 9% per annum in the coming years before the opening of the Deep Bay Link and the Sheung Shui-Lok Ma Chau spur line. However, Lok Ma Chau Crossing, being situated on the preferred route of cross-boundary traffic, is envisaged to be heavily used in the longer term. While the road system of Lok Ma Chau Crossing will be improved in stages to cope with the projected traffic growth, capacity deficiency is envisaged in the future at San Tin Interchange.

 

1.2              According to Transport Department’s assessment, the design flow/capacity ratios of the two approaches to San Tin Roundabout from San Tin Highway slip road and Fanling Highway slip road will exceed the allowable capacity in 2011. As such, improvements by means of two elevated roads are required to segregate the cross-boundary goods vehicles in order to relieve the traffic queues in the existing San Tin roundabout.

 

Purpose and Scope of the EIA

 

1.3              The two elevated slip roads are a Designated Project (the Project) under Schedule 2, Part I A.8 of the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and require an environmental permit under the EIAO for its construction and operation. 

1.4              An Environmental Impact Assessment (EIA) Study has been undertaken for the Project to provide information on the nature and extent of potential environmental impacts arising from the construction and operation of the proposed Project, and to contribute to decisions on the overall environmental acceptability of the Project. 

 

1.5              The EIA provided a detailed assessment of the potential environmental impacts associated with the Project, in relation to the issues specified in the EIA Study Brief No. ESB-092/2002, including noise, air quality, water quality, waste management, ecology, fisheries, cultural heritage, landscape and visual, and land contamination. 

 

 

2                    PROJECT DESCRIPTION

 

Location and Scale of Project

 

2.1              The proposed Project is located at the current San Tin Interchange in the North-West New Territories.  The two proposed elevated slip roads from westbound Fanling Highway and eastbound San Tin Highway will merge to form a 4-lane carriageway and then connect to San Sham Road leading to the existing vehicle holding area at the Lok Ma Chau Boundary Crossing.  The preliminary layout of the Project is shown in Figure 2.1. 

 

2.2              The main scope of this Project as defined in the EIA report will comprise:

(a)        provision of two elevated 2-lane slip roads of totally about 1.4 km in length from the westbound Fanling Highway and northbound San Tin Highway which will merge to form a 4-lane carriageway and then connect to San Sham Road leading to the existing vehicle holding area;

 

(b)        provision of two at-grade slip roads to connect Kwu Tung Road and Castle Peak Road to the elevated slip roads and San Sham Road;  

 

(c)        provision of a local widening of the existing Castle Peak Road with a box culvert extension; 

 

(d)        realignment of the at-grade existing slip roads connecting Castle Peak Road and San Tin Highway; and

 

(e)        provision of a bridge crossing the San Tin Eastern Main Drainage Channel (EMDC) and realignment of the EMDC maintenance access road to connect the existing access track to Castle Peak Road.

 

Project Programme

 

2.3              The construction of the Project is scheduled for commencement in April 2005 for completion in March 2007.

 

 

3                    ENVIRONMENTAL IMPACTS

 

3.1              Potential environmental impacts associated with the construction and operation phases of the proposed Project are summarized below.

Noise Impact

 

3.2              The assessment results indicated that noise mitigation measures would be required to abate the construction noise impact at village houses near San Tin Highway and Kwu Tung Road and Tun Yu School.  With the adoption of the quiet equipment and movable noise barriers, all noise sensitive receivers (NSR) would be protected against adverse noise impacts from the construction of the Project. 

 

3.3              The traffic noise assessment indicated that impact from the new roads (the proposed slip roads and the proposed section of Castle Peak Road to be widened) on all existing and planned NSRs would be within the EIAO Technical Memorandum noise criteria with the implementation of the recommended noise barriers.  Hence, adverse noise impact from the proposed project would not be anticipated.

 

Air Quality Impact

 

3.4              With the incorporation of dust control measures stipulated in the Air Pollution Control (Construction Dust) Regulation, the air modeling results showed that the TSP level at all air sensitive receivers (ASR) would be within the dust criteria. 

 

3.5              Vehicle exhaust emission would be the main pollution source during operation of the Project.  Air quality modeling results showed that the air quality objectives would be satisfied at all ASRs.

 

Water Quality Impact

 

3.6              The key issue in terms of water quality would be related to site formation and foundation works for the construction phase.  There are no fishponds within close proximity of the site boundary.  Mitigation measures to control runoff and drainage from the works areas were recommended to minimise construction run-off.  Proper site management and good housekeeping practices were also recommended to ensure that construction wastes would not enter the nearby nullahs.  With the implementation of these recommended mitigation measures, unacceptable impacts on water quality would not be anticipated. 

 

Waste Management Implications

 

3.7              Wastes generated by the construction activities would include C&D materials from the foundation works, general refuse from the workforce and chemical waste from any maintenance of construction plant and equipment.  Provided that these waste arisings are to be handled, transported and disposed of using the recommended methods and that good site practices are followed, adverse environmental impacts would not be anticipated.

 

Ecological Impact

 

3.8              Direct impacts to terrestrial habitats and species resulting from the Project would be limited to the loss of small areas of low value habitats. No species or areas of conservation interest would be affected.  Limited indirect impacts to wildlife resulting from construction phase disturbance have been predicted. Disturbance to the high ecological value fishponds north and north west of the works site are expected to be negligible, given the significant separation between the nearest ponds and the proposed works areas.  Overall, potential ecological impacts resulting from the Project were found to be minor and acceptable.

 

Fisheries Impact

 

3.9              The assessment area has only a very small area (approximately 1 ha) of active fish pond, none of which was located along or in close vicinity to the proposed slip roads.  The assessment indicated that none of the fish ponds would be directly lost or indirectly affected by the Project.  Therefore there would be no impact to pond aquaculture fisheries resources or operations. 

 

Cultural Heritage Impact

 

3.10          The assessment area was determined to contain no archaeological sites or areas of archaeological potential.  The impact assessment showed that there would be no adverse impacts to any of the recorded built heritage features and graves, therefore, no mitigation measures would be required. 

 

 

 

 

 

Landscape and Visual Impact

 

3.11          The landscape and visual impact assessment indicated that no significant impact would occur during construction and operation stages. The disturbance to existing road-side trees (approx. 0.9 ha), would either be transplanted or compensated in the form of advance planting at the beginning of the construction stage. The disturbed traffic corridor (2775 sq.m.) and industrial/utility (0.6 ha.) is man-made with low sensitivity to change.  The Project would result in negligible landscape impact and slight adverse visual impact, with adoption of mitigation measures. These landscape mitigation measures would mainly be located adjacent and underneath the viaduct, adjacent to the embankment, and apply to the noise barriers and the highway structure. In result, a total of 14,440sq.m of landscape mitigation measures would be provided to LCU2 transport corridor and 19,080 sq.m of landscape mitigation measures would be provided for LCU5 industrial/utility.

 

3.12          The landscape mitigation measure would minimize any adverse impacts.  It is predicted that the proposed improvement works would have limited landscape and visual impact, and considered as “acceptable with mitigation measures”.   The extent and location of the recommended landscape mitigation measures at both construction and operation stage is illustrated in the Landscape Master Plan.

 

Land Contamination

 

3.13          It was identified that two areas within the project boundary (existing open storage area at the section of Proposed Slip Road B near existing San Tin Interchange and existing open storage area at the southern portion of Slip Road H) appeared to be potentially contaminated.  Based on the available information, the potential of land contamination impact at the Study Area was considered surmountable. 

 

3.14          It was recommended that land contamination assessment be conducted at the identified areas prior to the commencement of site clearance / construction works.  During the construction phase, mitigation measures should be implemented in order to minimize the potential health impact on the construction workers.

Environmental Monitoring and Audit

 

3.15          An environmental monitoring and audit programme was recommended for construction noise and water quality.  Site inspection/audit was also recommended to check the implementation of the noise, air quality, water quality and waste management mitigation measures during the construction phase.  Details of the programme are presented in a separate Environmental Monitoring and Audit Manual. 

 

 

4                    Overall Conclusion

 

4.1              The findings of the EIA have provided information on the nature and extent of potential environmental impacts arising from the Designated Project element of the Improvements to San Tin Interchange project.  The EIA Study has predicted that the Project, after the adoption of appropriate mitigation measures, would comply with all environmental legislation and standards, with no adverse residual impacts.  An environmental monitoring and audit programme has been recommended to monitor the implementation of the mitigation measures and to ensure compliance with environmental standards.