12 CONCLUSION

12.1 Introduction

12.1.1 This EIA Report has provided an assessment of the potential environmental impacts associated with the construction and operation phases of the proposed Project.

12.1.2 Mitigation measures for the Project, as well as environmental monitoring and auditing requirements, have been developed during the detailed assessment. The Implementation Schedule of the recommended measures for the designated project, extension of Siu Ho Wan WTW, is presented in Section 13. The principal findings of this Report are summarised below.

12.2 Air Quality Impact

12.2.1 Air quality impacts from the construction works for existing Siu Ho Wan WTW, proposed Siu Ho Wan Raw Water Booster Pumping Station, Pui O raw water pumping stations and laying of raw water mains at Pui O would mainly be related to construction dust from excavation, demolition, materials handling and wind erosion. With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation and EM&A programme, dust impact on air sensitive receivers would be limited during the construction phase.

12.2.2 No operational air quality impact would be expected.

12.3 Noise Impact

12.3.1 Construction noise impacts from the laying of raw water mains, demolition and reprovisioning of Pui O Raw Water Pumping Station if unmitigated, would exceed daytime noise criterion at noise sensitive receivers (NSRs). The use of silenced PME and movable noise barriers during the raw water mains construction would be required to ensure no adverse noise impact on the NSRs. Scheduling of construction activities have also been proposed for mitigating impacts on Bui O Public School, during examination period. No construction noise impact would be expected in the area of the Project at Siu Ho Wan as no NSR is identified in that area.

12.3.2 The noise impact associated with the operation of the Pui O raw water pumping stations would not exceed the daytime and nighttime noise criteria. With the installation of acoustic louvers, which has a minimum insertion loss of 20 dB(A), for the ventilation fans and ventilation openings of the pump hall at the Pui O RWPS, The negligible noise impact from the operation of the Pui O raw water pumping stations is expected.

12.4 Water Quality Impact

12.4.1 The key water quality impact would be related to earthworks for the proposed extension of Siu Ho Wan WTW, the proposed Siu Ho Wan Raw Water Booster Pumping Station, trench excavation for the mainlaying works at Pui O and demolition works for Pui O Raw Water Pumping Station. The nearest identified water bodies to the works areas at Siu Ho Wan and Pui O are the existing streams at Pui O and the drainage channel to the north of the Siu Ho Wan WTW. Potential sources of water quality impact comprise construction site runoff and drainage; debris, refuse and liquid spillages from general construction activities; and sewage effluents from the construction workforce. Minimisation of water quality deterioration could be achieved through implementing adequate mitigation measures such as control measures on the runoff and drainage from the works areas to minimise construction run-off. Proper site management and good housekeeping practices would also be required to ensure that construction wastes and materials would not enter the nearby watercourses. Sewage effluent arising from the construction workforce would also require appropriate treatment through provision of portable toilets. With the implementation of appropriate mitigation measures, the construction works for the proposed Project would not be anticipated to result in adverse impacts on water quality.

12.5 Ecology

12.5.1 Construction of the proposed raw water mains at Pui O would mainly be confined to the existing South Lantau Road but at either end of proposed alignment would unavoidably directly impact woodland habitat. Vegetation clearance for excavation of a 2.5m wide trench would impact approximately 0.1ha of woodland habitat. The extent of the surrounding works area within woodland habitat would be approximately 0.4ha.

12.5.2 During field surveys, it was found that individuals of two locally common plant species of conservation interest (the protected shrub/tree Pavetta hongkongensis and IUCN listed tree Aquilaria sinensis) were scattered throughout the woodland habitat and may be directly impacted or disturbed by works. Provided that mitigation measures are implemented including transplantation of individual plants to a safe location where necessary, it was predicted that there would be no loss of these plants of conservation interest. Any transplants would be monitored for survival. In addition, tree felling would be minimised and replanting and landscaping would reinstate the works area.

12.5.3 With good site practice and implementation of environmental mitigation measures, other impacts, such as indirect impacts on stream water quality due to site runoff and indirect disturbance to wildlife would be very minor. It is anticipated that the Project would have no long-term residual impact on ecology of the Pui O Assessment Area.

12.5.4 Works at Siu Ho Wan would be mainly confined to existing site boundary and the proposed Siu Ho Wan Raw Water Booster Pumping Station built on highly disturbed very low ecological value developed/abandoned land and therefore minimal ecological impact is anticipated.

12.6 Landscape and Visual Impact

12.6.1 Potential landscape and visual impacts of the proposed works would be mainly related to the removal of existing vegetation, and proximity of the proposed structures to road users, working staffs in nearby working areas and local residents. The impacts in both Siu Ho Wan and Pui O sites would be greatly alleviated to acceptable with mitigation measures, namely Sympathetic Design of Structures and Design of External Appearance, Reinstatement of Planting on Disturbed Land, Compensatory Planting and a number of mitigation measures during construction period.

12.7 Cultural Heritage

Archaeology

12.7.1 The desk-based archaeological review identified no records of archaeological findings in Siu Ho Wan area and the study area of Proposed proposed Raw raw Water water Mains mains Alignment alignment at Pui O. Therefore, no cultural heritage impact is anticipated during construction orand operation phasess.

Built Heritage

12.7.2 Desk-based review identified historical villages in the vicinity of the proposed works at Pui O. The built heritage survey recorded a total of 24 resources. The majority of the heritage resources are located at a sufficient distance from the proposed works and will have no adverse impacts associated with the construction works.

12.7.3 However, mitigation measures in the form of a temporary fenced off buffer zone in proximity to the shrine SHW-01 at Pui O Lo Wai Tsuen with allowance for public access should be provided as far as practicable around the shrine SHW-01 at Pui O Lo Wai Tsuen as the demolition and reprovisioning works for the Pui O Raw Water Pumping Station may restrict access or damage affect the structure. In case of site constraint, the existing perimeter fence at Pui O Raw Water Pumping Station could be incorporated to protect the shrine and should form the limit of the buffer zone. No adverse impacts are expected during the operation phase.

12.7.4 No built heritage resources were identified near the proposed works at Siu Ho Wan.

12.8 Hazard to Life

12.8.1 A HAZOP study was conducted to identify additional chlorine hazards initiated by constructions activities.

12.8.2 A number of mitigation measures, such as monitoring and inspection of chlorine dosing facilities, management of materials and personnel, investigation and training, were identified to be included in the Contract document, as well as, in the Safety Plan and Emergency Plan for the extension of Siu Ho Wan WTW.

12.8.3 As it is expected that the proposed water treatment process after the extension of Siu Ho Wan WTW Water Treatment Works extension works would induce no increase of chlorine hazard in terms of storage or number of deliveries, no hazard assessment for the operation phase is required in this EIA Sstudy.

12.9 Waste Management

12.9.1 Wastes generated by the construction activities are likely to include construction & demolition (C&D) material from the earthworks for the extension of the Siu Ho Wan WTW, Siu Ho Wan Raw Water Booster Pumping Station and the mainlaying works along South Lantau Road at Pui O and demolition works for Pui O Raw Water Pumping Station, general refuse from the workforce and chemical wastes from plant and equipment maintenance. Provided that these identified waste arisings are to be handled, transported and disposed of using the recommended methods and that good site practices are to be strictly followed, adverse environmental impacts would not be anticipated during the construction works.

12.9.2 Waste management will be the contractor’s responsibility to ensure that all wastes produced during the construction of the Project are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. The recommended mitigation measures will form the basis of the site Waste Management Plan to be developed by the Contractor at the commencement of the construction phase.

12.10 Environmental Monitoring and Audit

12.10.1Environmental monitoring and audit of dust, noise, ecology and landscape and visual during construction phase were recommended. Site inspection / audit was also recommended for water quality, cultural heritage and waste management during construction phase. Details of the recommended mitigation measures, monitoring procedures and locations were presented in a stand-alone Environmental Monitoring and Audit (EM&A) Manual.

12.11 Overall Conclusion

12.11.1The findings of this EIA have provided information on the nature and extent of environmental impacts arising from the construction and operation of the Project.

12.11.2The EIA Report has predicted that, the Project would be environmentally acceptable in compliance with environmental standards and legislation with the implementation of the construction and operation stages mitigation measures, environmental monitoring and audit programme. Table 12.1 summarizes the environmental outcomes/benefits from the implementation of the Project and the recommended mitigation measures.

Table 12.1 Summary of Key Environmental Outcomes/Benefits

Area/Issue	Environmental Outcomes/Benefits and Mitigation Measures
The Project	In order to cope with the anticipated increase in water demand generated from the existing and proposed developments in North Lantau New Town, Discovery Bay, Northshore Lantau, Ngong Ping and the International Theme Park at Penny’s Bay, it is necessary to complete the extension work to Siu Ho Wan WTW by the end of 2011.
Site Selection	Two options for the Siu Ho Wan Raw Water Booster Pumping Station were considered. The proposed site located adjacent to the Siu Ho Wan WTW was recommended and has the following benefits: less site formation work and slope stabilization works; no restrictions on future extension of the Siu Ho Wan Raw Water Booster Pumping Station; more convenient in operation and maintenance; and lower ecological impact and landscape impact. Two options of raw water mains alignments at Pui O were considered. The proposed alignment along South Lantau Road was recommended and has the following benefits: lower ecological, landscape and visual and cultural heritage impacts; and no private land resumption nor public land rezoning would be required.
Noise	Construction noise impacts from the laying of raw water mains, demolition and reprovisioning of Pui O Raw Water Pumping Station if unmitigated, would exceed daytime noise criterion at the representative NSRs. Use of silenced PME and movable noise barriers was therefore recommended. ~~Scheduling of construction activities~~ ~~was~~ ~~proposed for mitigating~~ ~~noise~~ ~~impacts on Bui O Public School during examination period.~~ No operational noise exceedance at the representative NSRs was predicted from operation of the Pui O raw water pumping stations. if the recommended noise mitigation measures are implemented. No NSRs identified in the area of Siu Ho Wan.
Air Quality	Potential dust impacts would mainly be related to construction dust from excavation, demolition, materials handling and wind erosion. Dust suppression methods and good site practices were proposed to protect ASRs in the vicinity of the works areas in Siu Ho Wan and Pui O areas. No operational air quality impact would be expected.
Water Quality	The key potential water quality impact would be related to earthworks for the proposed extension of Siu Ho Wan WTW, the proposed Siu Ho Wan Raw Water Booster Pumping Station, trench excavation for the mainlaying works at Pui O and demolition works for Pui O Raw Water Pumping Station. The nearest identified water bodies to the works areas at Siu Ho Wan and Pui O are the existing streams at Pui O and the drainage channel to the north of the Siu Ho Wan WTW. Potential impacts from construction activities would be minimized by implementing the recommended mitigation measures, such as control measures on runoff and drainage from work areas to minimize construction run-off and proper site management and good housekeeping practices.
Ecology	Construction of the proposed raw water mains at Pui O would mainly be confined to the existing South Lantau Road. However, both ends of the proposed alignment would directly impact woodland habitat. Vegetation clearance for excavation of a 2.5m wide trench would impact approximately 0.1ha of woodland habitat. The extent of the surrounding works area within woodland habitat would be approximately 0.4ha. Individuals of two locally common plant species of conservation interest (the protected shrub/tree Pavetta hongkongensis and IUCN listed tree Aquilaria sinensis) were found scattered throughout the woodland habitat and may be directly impacted or disturbed by the proposed mainslaying works. Transplantation of individual plants to a safe location within the same habitat was proposed. Indirect impacts, such as impacts on stream water quality due to site runoff and disturbance to wildlife, were predicted to be very minor with the implementation of good site practices. Minimal ecological impact is anticipated from the proposed works at Siu Ho Wan.
Waste Management	Identified waste arisings include construction & demolition (C&D) material from the earthworks for the extension of the Siu Ho Wan WTW, Siu Ho Wan Raw Water Booster Pumping Station and the mainlaying works along South Lantau Road at Pui O and demolition works for Pui O Raw Water Pumping Station, general refuse from the workforce and chemical wastes from plant and equipment maintenance. Provided that these construction waste arisings are handled, transported and disposed of using the recommended methods and that good site practices are strictly followed, adverse environmental impacts would not be anticipated during the construction works.
Cultural Heritage	No records of archaeological findings were identified in the Siu Ho Wan and Pui O site areas. The majority of the identified built heritage resources are located a sufficient distance from the proposed works areas and would not be adversely impacted. Demolition and reprovisioning works for the Pui O Raw Water Pumping Station may restrict access or affect the structure of a shrine at Pui O Lo Wai Tsuen. Mitigation measures in the form of a temporary fenced-off buffer zone were recommended. No built heritage resources were identified in the vicinity of the proposed works at Siu Ho Wan.
Landscape and Visual	Potential landscape and visual impacts would be mainly related to the removal of existing vegetation and the proximity of the proposed structures to road users, staff working in nearby areas and local residents. The impacts in Siu Ho Wan and Pui O sites would be alleviated to acceptable levels with the implementation of recommended mitigation measures, such as sympathetic design of structures and design of external appearance, reinstatement of planting on disturbed land, and compensatory planting.
Hazard to Life	A HAZOP study was conducted to identify additional chlorine hazards initiated by constructions activities. Mitigation measures were proposed, such as monitoring and inspection of chlorine dosing facilities, management of materials and personnel, investigation and training, for inclusion in the Contract document and the Safety Plan and Emergency Plan. The proposed water treatment process after the extension of Siu Ho Wan WTW would not induce any increase of chlorine hazard in terms of storage or number of deliveries.

Area/Issue

Environmental Outcomes/Benefits and Mitigation Measures

The Project

In order to cope with the anticipated increase in water demand generated from the existing and proposed developments in North Lantau New Town, Discovery Bay, Northshore Lantau, Ngong Ping and the International Theme Park at Penny’s Bay, it is necessary to complete the extension work to Siu Ho Wan WTW by the end of 2011.

Site Selection

Two options for the Siu Ho Wan Raw Water Booster Pumping Station were considered. The proposed site located adjacent to the Siu Ho Wan WTW was recommended and has the following benefits: less site formation work and slope stabilization works; no restrictions on future extension of the Siu Ho Wan Raw Water Booster Pumping Station; more convenient in operation and maintenance; and lower ecological impact and landscape impact.

Two options of raw water mains alignments at Pui O were considered. The proposed alignment along South Lantau Road was recommended and has the following benefits: lower ecological, landscape and visual and cultural heritage impacts; and no private land resumption nor public land rezoning would be required.

Noise

Construction noise impacts from the laying of raw water mains, demolition and reprovisioning of Pui O Raw Water Pumping Station if unmitigated, would exceed daytime noise criterion at the representative NSRs. Use of silenced PME and movable noise barriers was therefore recommended. ~~Scheduling of construction activities~~ ~~was~~ ~~proposed for mitigating~~ ~~noise~~ ~~impacts on Bui O Public School during examination period.~~

No operational noise exceedance at the representative NSRs was predicted from operation of the Pui O raw water pumping stations. if the recommended noise mitigation measures are implemented.

No NSRs identified in the area of Siu Ho Wan.

Air Quality

Potential dust impacts would mainly be related to construction dust from excavation, demolition, materials handling and wind erosion. Dust suppression methods and good site practices were proposed

to protect ASRs in the vicinity of the works areas in Siu Ho Wan and Pui O areas.

No operational air quality impact would be expected.

Water Quality

The key potential water quality impact would be related to earthworks

for the proposed extension of Siu Ho Wan WTW, the proposed Siu Ho Wan Raw Water Booster Pumping Station, trench excavation for the mainlaying works at Pui O and demolition works for Pui O Raw Water Pumping Station. The nearest identified water bodies to the works areas at Siu Ho Wan and Pui O are the existing streams at Pui O and the drainage channel to the north of the Siu Ho Wan WTW. Potential impacts from construction activities would be minimized by implementing the recommended mitigation measures, such as control measures on runoff and drainage from work areas to minimize construction run-off and proper site management and good housekeeping practices.

Ecology

Construction of the proposed raw water mains at Pui O would mainly be confined to the existing South Lantau Road. However, both ends of the proposed alignment would directly impact woodland habitat. Vegetation clearance for excavation of a 2.5m wide trench would impact approximately 0.1ha of woodland habitat. The extent of the surrounding works area within woodland habitat would be approximately 0.4ha. Individuals of two locally common plant species of conservation interest (the protected shrub/tree Pavetta hongkongensis and IUCN listed tree Aquilaria sinensis) were found scattered throughout the woodland habitat and may be directly impacted or disturbed by the proposed mainslaying works. Transplantation of individual plants to a safe location within the same habitat was proposed.

Indirect impacts, such as impacts on stream water quality due to site runoff and disturbance to wildlife, were predicted to be very minor with the implementation of good site practices.

Minimal ecological impact is anticipated from the proposed works at Siu Ho Wan.

Waste Management

Identified waste arisings include construction & demolition (C&D) material from the earthworks for the extension of the Siu Ho Wan WTW, Siu Ho Wan Raw Water Booster Pumping Station and the mainlaying works along South Lantau Road at Pui O and demolition works for Pui O Raw Water Pumping Station, general refuse from the workforce and chemical wastes from plant and equipment maintenance. Provided that these construction waste arisings are handled, transported and disposed of using the recommended methods and that good site practices are strictly followed, adverse environmental impacts would not be anticipated during the construction works.

Cultural Heritage

No records of archaeological findings were identified in the Siu Ho Wan and Pui O site areas.

The majority of the identified built heritage resources are located a sufficient distance from the proposed works areas and would not be adversely impacted. Demolition and reprovisioning works for the Pui O Raw Water Pumping Station may restrict access or affect the structure of a shrine at Pui O Lo Wai Tsuen. Mitigation measures in the form of a temporary fenced-off buffer zone were recommended.

No built heritage resources were identified in the vicinity of the proposed works at Siu Ho Wan.

Landscape and Visual

Potential landscape and visual impacts would be mainly related to the removal of existing vegetation and the proximity of the proposed structures to road users, staff working in nearby areas and local residents. The impacts in Siu Ho Wan and Pui O sites would be alleviated to acceptable levels with the implementation of recommended mitigation measures, such as sympathetic design of structures and design of external appearance, reinstatement of planting on disturbed land, and compensatory planting.

Hazard to Life

A HAZOP study was conducted to identify additional chlorine hazards initiated by constructions activities. Mitigation measures were proposed, such as monitoring and inspection of chlorine dosing facilities, management of materials and personnel, investigation and training, for inclusion in the Contract document and the Safety Plan and Emergency Plan.

The proposed water treatment process after the extension of Siu Ho Wan WTW would not induce any increase of chlorine hazard in terms of storage or number of deliveries.