EXECUTIVE SUMMARY

 

An Environmental Impact Assessment (EIA) was carried out for the proposed Sheung Shui to Lok Ma Chau Spur Line railway to identify and quantify potential environmental impacts and formulate suitable mitigation measures. Engineering and railway design constraints have defined the selected alignment. Of five conceived alignments, insurmountable engineering constraints determined that only the proposed Spur Line alignment was feasible (Figure 1). This feasible alignment passes through several ecologically sensitive areas (including the Wetland Conservation Area (WCA)), plus several rural communities. In addition, it is within the drainage basin of Deep Bay, a sensitive water body receiving pollution discharges from a rapidly developing catchment. The environmental assessment of the feasible route is presented here and includes: construction and operational noise, ecology, visual and landscape aspects, water quality, air quality, waste, contaminated land, fisheries and cultural heritage.

 

Noise

 

Noise is of concern as some residential units are close to the track and the area is rural/semi-rural. For short periods, excavation at Pak Shek Au and construction of the western alignment will result in noise levels above the recommended construction noise level. However, this impact can be minimized by careful scheduling of the works.

 

Operational noise impact will be mitigated by installing Floating Slab Track (FST) along the eastern section of the viaduct. LVT will be installed on the western portion of the viaduct. Morning traffic is at a maximum between 0600 to 0700 hours when the noise criteria are most stringent. At this time, six skirted trains will be operated in each direction. Together with the standard walkway plenum, a multi-plenum system will be formed to achieve significant airborne noise reduction along all sections of the viaduct. Consideration is being given to the provision of additional mitigation measures at key locations, which would allow operation of unskirted East Rail trains during the critical 0600-0700 period. A 1.2m tall trackside parapet will be installed as part of the standard viaduct designed to provide further screening of airborne noise. Provision will be made to provide additional noise screening above the trackside parapet to cater for future development along the Spur Line. Just north of Tsung Pak Long, a 200m long, 2m tall noise barrier is proposed to be installed at 4.5m from the track centreline. A full enclosure is proposed to cover the points and crossings just north of Sheung Shui station to compensate for the loss of sound reduction otherwise provided by the multi-plenum system. A sidewall and walkway will form a single plenum on the ballasted at grade cutting/embankment section west of Kwu Tung.

 

Consideration of future development along Spur Line, in particular Kwu Tung SGA, indicates that, for sensitive receivers close to the railway reserve, some mitigation may be required in the form of reduced train speed or additional barriers/enclosures. Assessment of cumulative impacts indicates that the existing East Rail operation has a significantly higher noise level (more than 10 dB(SA) higher) than that arising from Spur Line operation. Mitigation for Spur Line will also reduce noise levels on existing East Rail operation.

 

Ecology

 

Potentially high impacts may occur as a result of disturbance and the loss of fishponds (mainly resulting from the station complex) within the Wetland Conservation Area near Lok Ma Chau. Moderate impacts may occur from disturbance and some loss of agricultural habitats and marshlands in Long Valley. Impacts on Long Valley have been minimized through design, by putting the railway on viaduct and minimizing noise and vibration through appropriate mitigation measures.

 

Mitigation of long-term ecological impacts at Lok Ma Chau includes the provision of an area of approximately 28.5 ha of fishponds around the proposed station, that will be managed to enhance their ecological value (Figure 2). Potential construction impacts will be minimized by creation of shallow feeding areas and/or water level management in selected ponds in the west of the mitigation area. Potential disturbance impacts during construction in the Long Valley marsh area will be mitigated through the restriction of contractor access and the establishment of an alternative 1.8 3 ha temporary wetland area to the west of the River Beas. Long-term impacts in Long Valley will be mitigated through wetland creation and enhancement below the viaduct approximately (2.4 ha), and a management scheme (involving an area of 1.4 ha) that co-ordinates with other ecological mitigation measures associated with the Main Drainage Channel Scheme (River Beas) (Figure 3). Responsibility for the long-term management of the ecological habitat compensation areas will be handed over to the HKSAR Wetland Trustwetland management organisation, that is in the process of being established. KCRC will make a lump sum donation to the Wetland Trustwetland management organisation, which the trustees will invest the money to cover the recurrent costs of the wetland management.when it is set up and takes over the management and maintenance of the ecological compensation areas.

 

The ecological compensation proposed for the Spur Line project is unique in Hong Kong in its consideration of habitat loss and disturbance impacts, and provision for early compensation of construction impacts in the Long Valley marsh area and the Lok Ma Chau fishponds area. This approach allows a mechanism for the long term protection and management of Hong Kong’s ecological resources.

 

Landscape and Visual Character

 

The landscape and visual character of the Spur Line corridor is varied, ranging from open and low lying agricultural and fish pond areas at the eastern and western ends of the alignment; to the more developed cottage areas and the existing New Territories Circular Road corridor in the valley between Tit Hang and Ki Lun Shan hills in the central section. This is reflected in the visual context with views at either end of the proposed alignment being open and rural in character, and the available views in central section being more enclosed and screened.

 

Landscape impacts include disturbance to the existing vegetation, agricultural and fish pond areas, together with the introduction of a major infrastructure element into the largely rural landscape. The proposed scheme would not have a significant effect on the landscape resources of the study area although approximately 1894 trees would be felled and a further 119 would be transplanted to new locations.  Visual impacts would arise from the introduction of the viaduct sections into the low lying landscape, the new cut slopes and embankments, the proposed noise enclosure and barriers at Sheung Shui station and the new Lok Ma Chau station complex.

 

The mitigation measures have been designed to integrate the proposals into the existing landscape of fishponds, agricultural land, open storage and cottage areas, and the future landscape represented by the Kwu Tung North SGA. In order to achieve this landscape ‘fit’ into the future SGA landscape the planting of woodland was considered a more practicable mitigation solution than the replacement of other landscape resources which would no longer be characteristic of the rail corridor. The proposed planting of some 12 hectares of woodland would more than compensate for the loss of woodland resulting from the scheme. This is equal to approximately 4300 trees in the proposed mitigation planting areas.

 

The proposed viaduct structures have been designed to be visually ‘light’ and exhibit a graceful, curving alignment in Long Valley and at the western end of the alignment near Lok Ma Chau. The scope for landscape mitigation measures for the eastern section of viaduct was limited by ecological requirements, and at the western end by the existing fishpond areas. However clumps of tree and shrub planting would be used, where space allows, to break up the horizontal visual emphasis of the western viaduct structure. Also the existing fishponds would be restored below the viaduct. The viaduct would fit into the general context of the infrastructure developments in the area.

 

The station would be set against a high-rise urban backdrop of Shenzhen and providing appropriate materials are used in the station construction, glare will not be a major source of impact. Implementation of the proposed measures will minimise landscape and visual impacts.

 

The landscape and visual character of the Spur Line site shows open and low lying agricultural and fishpond areas at each end, and more developed cottage areas and a road corridor in the valley between the Tit Hang and Ki Lun Shan hills. Landscape impacts include disturbance to vegetation, agricultural areas and fishponds, together with the introduction of a major infrastructure element to the landscape. Mitigation measures include compensatory planting, re-instatement of fishpond areas and design of the viaduct to integrate with the local landscape character. Visual impacts arise from the introduction of the viaduct in low lying areas, the new cut slopes and embankments and noise barriers which may be required for noise mitigation. Within the requirements of the ecological wetland mitigation, bamboo planting will be used to break up the linear form of the viaduct and reduce its visual intrusion. Visual impacts of noise barriers will be mitigated through design detailing. The station will be set against the high-rise urban backdrop of Shenzhen, resulting in low impact. Glare from the station will be avoided through the use of suitable non-reflective materials. In addition, these visible materials will help to prevent bird strike.

Water Quality

 

Potential construction impacts on water quality during the construction phase include turbid, nutrient-rich run-off from excavation activities, increased pH and ammonia toxicity from concrete washings, particularly during construction of the footbridge across Shenzhen River, chemical spillage and wastewater generation on site. A well designed and maintained site drainage system, correct handling and disposal of concrete washings and other wastewaters, appropriate control of chemicals, and provision of adequate facilities for site workers will minimize potential impacts during construction. All watercourses in the area are within the Deep Bay Water Control Zone and discharges to these watercourses are subject to the zero discharge policy (ZDP). Potential operational impacts from the Spur Line railway involve hydraulic and pollution impacts from stormwater run-off from the railway tracks and the trains, hydraulic impacts from the footbridge across Shenzhen River, and pollution from sewage generated at Lok Ma Chau station.

 

Appropriate design of the footbridge piers will minimise hydraulic impacts and turbidity downstream. The footbridge will be designed and constructed by a Mainland Chinese Company. It will therefore not be subject to Environmental Permit conditions arising from this EIA. Stormwater pollution will be minimized through the incorporation of appropriate pollution control measures such as oil interceptors/sediment traps into the drainage system design, and regular maintenance of the system. Compliance with ZDP will be achieved by polishing the sewage treatment works effluent in a reedbed around Lok Ma Chau Station, and treating a pollution load from the adjacent river channel, equivalent to the pollution load discharged from the development.

 

Air Quality

 

Recommended dust suppression measures during construction include watering of haul roads and covering or treating exposed earth surfaces wherever possible. Air quality impacts arising from the operational phase of the Spur Line are not of concern as limited potential emission sources have been identified.

 

Waste

 

Waste from construction and operation of Spur Line, will comprise excavated material, concrete, wood formwork, steel poles, chemical wastes, wheel wash wastes and general refuse. A waste management strategy is described, including methods for recycling or disposal, and responsibilities for implementation and management of the waste management procedure

 

Contaminated Land

 

Potentially contaminated land was identified at several locations along the alignment. A Contamination Assessment Plan (CAP) is proposed, which includes excavation of trial pits and boreholes followed by a sampling and analysis programme to determine the type and extent of contamination. Following the production of the Contamination Assessment Report (CAR), an evaluation of the mitigation measures to be used, including re-use on site, disposal or remediation will be prepared.

 

Fisheries

 

Fish ponds temporarily lost during construction phase will be reinstated. Responsibility for the long-term management of ponds in the ecological mitigation areas will be handed over to the HKSAR Wetland TrustWetland management organisation. The trustees will arrange for the management and maintenance of the ponds in accordance with the requirements of the EIA and the Habitat Creation and Management Plan to be prepared during the detailed design stage.

 

Cultural Heritage

 

Cultural heritage survey has determined that there are no historical buildings which lie directly on the Alignment. A survey for prehistoric archaeological remains within the study area has not found sites that would be impacted. However, it is recommended that precautionary measures be included within the Works, with particular emphasis on the area to the south of Ho Sheung Heung where Sung material was found during survey. This area should be monitored during the excavations associated with the viaduct support columns. Mitigation in the form of specification of working practices and screening of visual effects is recommended to the historic buildings which face the Spur Line, such as Ho Sheung Heung village which contains notable cultural heritage resources.

 

Environmental Monitoring and Audit

 

Environmental monitoring and audit requirements for the construction phase are described in terms of the monitoring locations, periods of time, frequency and standards against which the monitoring results should be compared to determine compliance. Operational monitoring will be required for the wetland compensation areas to determine the success of their establishment. An Implementation Schedule for the works is included in the EIA report.

 

Conclusion

 

The conclusion of the EIA is that no insurmountable environmental impacts will result from implementation of the Spur Line project.