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1.                            INTRODUCTION


1.1                        Background


1.1.1                  The project is entitled “Improvement of Fresh Water Supply to Cheung Chau” (hereinafter referred to as “the Project”). Figure 1.1 shows the location of the proposed Project. Figure 1.2 shows the aerial view of the Project.


1.1.2                  Cheung Chau, with a population of around 23,000, is currently supplied with treated water from Silver Mine Bay Water Treatment Works on Lantau via two submarine water mains, 10” (about 250 mm) and 500 mm in diameter, across Adamasta Channel. Treated water is normally provided by the 500 mm diameter main, with the 10” main serving as emergency backup.


1.1.3                  Laid in 1963, the existing 10” submarine water main providing partial emergency back up fresh water supply to Cheung Chau is approaching the end of its design life of 50 years.  Repairs would be uneconomical and take a long time given the difficulty of the task and the condition of the main. To improve the reliability of water supply to Cheung Chau, it is necessary to strengthen the emergency back up by replacing the existing 10” submarine water main with a new 500 mm diameter submarine water main.


1.1.4                  Black & Veatch Hong Kong Limited was commissioned by Water Supplies Department (WSD) to study the feasibility of laying the proposed submarine pipeline and associated land mains, identify alternative sites and alignments if necessary.


1.1.5                  The Project is to construct and operate a new submarine water main across Adamasta Channel from Lantau to Cheung Chau to replace the existing submarine water main, which is serving as emergency back up, to improve the reliability of water supply to Cheung Chau.


1.2                        Requirements under the Environmental Impact Assessment Ordinance


1.2.1                  The Project is a Designated Project (DP) under the Environmental Impact Assessment Ordinance (EIAO) (Cap.499) by virtue of:


(i)               Item Q.1, Part 1, Schedule 2 of the EIAO : All projects including new access roads, railways, sewers, sewage treatment facilities, earthworks, dredging works and other building works partly or wholly in an existing or gazetted proposed country park or ….(The landfall at Lantau falls within the existing Lantau South Country Park.)


1.2.2                  In accordance with the EIAO, an environmental Impact Assessment (EIA) report is required to be prepared to meet the requirements under the EIAO and for an Environmental Permit to be obtained for the construction and operation of the Project.


1.2.3                  An application (No. ESB-187/2008) for an EIA study brief under section 5(1)(a) of the EIAO was submitted on 24 April 2008 with a Project Profile (No. PP-351/2008).


1.2.4                  Pursuant to section 5(7)(a) of the EIAO based on the project information given in the Project Profile, the Director of Environmental Protection (the Director) issues an EIA study brief (ESB-187/2008) in May 2008 to the Applicant to carry out an EIA study.


1.3                        Purpose and Objective of the Environmental Impact Assessment (EIA) Study


1.3.1                  The purpose of the EIA study is to provide information on the nature and extent of environmental impacts arising from the construction and operation of the Project and related activities taking place concurrently. This information will contribute to decisions by the Director of Environmental Protection on:


(i)               the acceptability of adverse environmental consequences that are likely to arise as a result of the Project;


(ii)             the conditions and requirements for the design, construction and operation of the Project to mitigate against adverse environmental consequences; and


(iii)            the acceptability of residual impacts after the proposed mitigation measures are implemented.


1.3.2                  The objectives of the EIA study are as follows:


(i)               to describe the Project and associated works together with the requirements for carrying out the proposed Project and the types of designated project(s) to be covered by the Project;


(ii)             to identify and describe the elements of the community and environment likely to be affected by the Project and/or likely to cause adverse impacts to the Project, including both the natural and man-made environment and the associated environmental constraints;


(iii)            to provide information on the consideration of alternative options of water main alignment, landfalls locations and construction method with a view to avoiding or minimizing the potential environmental impacts to environmentally sensitive areas and other sensitive uses; to compare the environmental benefits and disbenefits of each of the different options; to provide reasons for selecting the preferred option(s) and to describe the part environmental factors played in the selection;


(iv)           to identify and quantify emission sources and determine the significance of impacts on sensitive receivers and potential affected uses;


(v)             to identify and quantify any potential loss or damage and other potential impacts to ecology and fisheries resources, flora, fauna and natural habitats and to propose measures to mitigate these impacts;


(vi)           to identify any negative impacts on archaeological resources and to propose measures to mitigate these impacts;


(vii)          to propose the provision of mitigation measures so as to minimize pollution, environmental disturbance and nuisance during construction and operation of the Project;


(viii)        to investigate the feasibility, practicability, effectiveness and implications of the proposed mitigation measures;


(ix)           to identify, predict and evaluate the residual environmental impacts (i.e. after practicable mitigation) and the cumulative effects expected to arise during the construction and operation of the Project in relation to the sensitive receivers and potential affected uses;


(x)             to identify, assess and specify methods, measures and standards to be included in the detailed design, construction and operation of the Project which are necessary to mitigate these environmental impacts and cumulative effects and reduce them to acceptable levels;


(xi)           to investigate the extent of the secondary environmental impacts that may arise from the proposed mitigation measures and to identify constraints associated with the mitigation measures recommended in the EIA study, as well as the provision of any necessary modification; and


(xii)          to design and specify environmental monitoring and audit requirements to check the effective implementation of the recommended environmental protection and pollution control measures.


1.4                        Approach of the EIA Study


1.4.1                  The EIA study is conducted in accordance with the requirements set out in the EIA study brief and the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).


1.5                        Structure of the EIA Report


1.5.1                  The backgrounds, descriptions and justifications of this Project are provided in Chapter 2. The preliminary design proposal and the landscaping design measures of the Project as required in the EIA study brief is also provided in Chapter 2. For each of the environmental parameters that have been identified, assessment results and mitigation measures are presented in the following sections.


·                  Chapter 3 – Water Quality Impact Assessment

·                  Chapter 4 – Ecological Impact Assessment

·                  Chapter 5 – Fisheries Impact Assessment

·                  Chapter 6 – Cultural Heritage Impact Assessment

·                  Chapter 7 – Construction Waste Management

·                  Chapter 8 – Construction Noise Impact Assessment

·                  Chapter 9 – Environmental Monitoring and Audit Requirements

·                  Chapter 10 – Environmental Outcomes

·                  Chapter 11 – Conclusion


1.5.2                  The Implementation Schedule of the mitigation measures recommended in this EIA report and details pertaining to the impact assessment are attached in the Appendices.



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