1.                  INTRODUCTION

1.1              Project Background

1.1.1        The existing Siu Ho Wan Water Treatment Works (hereinafter referred to as Siu Ho Wan WTW) and the associated raw water and treated water transfer and distribution systems were commissioned in 1997 to provide treated water capacity of 150,000 m3/day.  It provided treated water to the Hong Kong International Airport at Chek Lap Kok and the initial phases of North Lantau New Town and Discovery Bay.


1.1.2        Water Supplies Department (WSD) commissioned consultants to conduct a Preliminary Project Feasibility Study (hereinafter referred to as PPFS) in respect of the project “Siu Ho Wan Water Treatment Works Extension” (hereinafter referred to as the Project) in January 1999.  The PPFS gave the requirements of the Project, describing the studies undertaken and the new works required, together with the outline design for principal elements of the Project, cost estimate, land requirements and implementation programme.


1.1.3        Following the PPFS, Metcalf & Eddy Ltd. has been commissioned by WSD to carry out the Extension of Siu Ho Wan Water Treatment Works - Investigation under Agreement No. CE 75/2002 (WS) (the Assignment).  The Environmental Impact Assessment Study (EIA) study of the assignment has been undertaken by Maunsell Environmental Management Consultants Ltd.


1.1.4        The proposed Project comprises the extension of Siu Ho Wan WTW and the associated raw water and treated water transmission systems to cope with the water demands of the developments in North Lantau New Town, northshore & north-east Lantau area and Discovery Bay.      


1.2              Objectives of EIA Study

1.2.1        In accordance with the EIA Study Brief for the Project, registered under the Environmental Impact Assessment Ordinance (EIAO) as “Siu Ho Wan Water Treatment Works Extension” (Ref No. ESB-046/2000), 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 proposed designated Project and related activities taking place concurrently.  This information will contribute to decisions on whether or not:


·         overall acceptability of any adverse environmental consequences that are likely to arise as a result of the proposed Project;

·         the conditions and requirements for the detailed design, construction and operation of the proposed Project to mitigate against adverse environmental consequences wherever practicable; and

·         the acceptability of residual impacts after the proposed mitigation measures are implemented.


1.2.2        The objectives of this EIA Study are:


·         to describe the Project and associated works together with the requirements for carrying out the proposed Project;

·         to identify and describe the elements of the community and environment likely to be affected by the proposed Project and / or likely to cause adverse impacts to the Project, including both the natural and man-made environment;

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

·         to identify and quantify an potential losses and damages to flora, fauna and natural habitats;

·         to identify any negative impacts on sites of cultural heritage and to propose measures to mitigate theses impacts;

·         to identify and assess any potential landscape and visual impacts and to propose measures to mitigate these impacts;

·         to propose the provision of infrastructure or mitigation measures so as to minimize pollution, environmental disturbance and nuisance during construction and operation of the Project;

·         to identify, predict and evaluate the residual environmental impacts and the cumulative effects expected to arise during the construction and operation phases of the Project in relation to the sensitive receivers and potential affected uses;

·         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 reducing them to acceptable levels;

·         to investigate the extent of side –effects of proposed mitigation measures that may lead to other forms of impacts;

·         to identify constraints associated with the mitigation measures recommended in the EIA study; and

·         to design and specify the environmental monitoring and audit requirements, if required, to ensure the implementation and the effectiveness of the environmental protection and pollution control measures adopted.


1.3              Consideration of Environmental Impact Assessment Ordinance

1.3.1        The proposed extension of Siu Ho Wan WTW from 150,000m3/day to 300,000m3/day is a designated project, which is classified as Category E.2 under Schedule 2 Part I of the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499).  It requires an environmental permit under the EIAO for the implementation of the Project.   


1.4              EIA Study Area

1.4.1        The following definitions of the study areas have been adopted with reference to the EIA Study Brief:


·          Air quality assessment – area covers a distance of 500m from the Project boundary.


·          Noise impact assessment – areas within 300 m from the Project boundary.  If the first layer of noise sensitive receivers provides acoustic shielding to those receivers further from the site, the assessment area could be reduced accordingly.


·          Water quality impact assessment - area within a distance of 500m from the Project boundary.


·          Ecological impact assessment - areas within 500 m distance from site boundary or likely to be impacted by the Project for terrestrial ecological assessment.  For aquatic ecology, the assessment area should be the same as for water quality assessment.


·          Landscape and visual impacts - the assessment area for landscape impact assessment should include areas within a 500 m distance from the work limit of the proposed Project, while the assessment area for the visual impact assessment shall be defined by the visual envelope of the Project.


·          Cultural heritage impact  - all sites of cultural heritage that might be adversely affected by construction activities of the Project.


·          Hazard to Lifeassessment – consultation zone for the Potentially Hazardous Installation at Siu Ho Wan WTW as described in Section 9.


·          Waste Management – assessment focused on areas within the Project boundary.


1.5              Structure of the EIA Report

1.5.1        The remainder of this EIA Report is set out below:


·          Section 2 illustrates the Project location, the scope of development, option evaluation on the siting for proposed Siu Ho Wan Raw Water Booster Pumping Station and proposed raw water mains alignment at Pui O, the EIA Study Area and works programme that have been considered under the Project;


·          Sections 3 to 8 assesses potential air quality, noise, water quality, ecological, landscape and visual, and cultural heritage impacts associated with the construction and operation of the Project respectively;


·          Section 9 assesses any additional chlorine hazards during construction activities and operation phase;


·          Section 10 identifies potential waste management implication associated with the construction and operation of the Project;


·          Section 11 presents key Environmental Monitoring & Audit (EM&A) requirements;


·          Section 12 summarises and concludes findings of EIA; and


·          Section 13 provides Implementation Schedule.