Background

1.1. In 1993 the Environmental Protection Department (EPD) commissioned a Sewerage Master Plan (SMP) study of the Outlying Islands. The areas studied included: Lantau Island, Lamma Island, Cheung Chau, Peng Chau and some other smaller islands to the west and south of Hong Kong. The SMP was completed in 1994 and made recommendations which included some improvements and extensions to the existing sewerage infrastructure.

1.2. Further to the SMP Study, Drainage Services Department (DSD) was commissioned by Environmental Protection Department (EPD) to carry out a Preliminary Project Feasibility Study (PPFS) for the Outlying Islands Sewerage Stage 1 Phase II in 1996. The Project which forms part of the Outlying Island Sewerage Project, includes the design and construction of sewerage at Cheung Chau, Peng Chau and Lamma Island (Sok Kwu Wan and Yung Shue Wan).

1.3. Package J, which is one of the packages under the Outlying Islands Sewerage Stage 1 Phase II, consists of provision of sewage treatment and disposal facilities as well as a sewerage system including pumping stations and rising mains to collect and transfer the sewage and wastewater arising from the Sok Kwu Wan catchment areas to the proposed sewage treatment and disposal facilities. On 1st May 1998 Drainage Services Department (DSD) commissioned Maunsell Consultants Asia Ltd (MCAL) as lead consultants to implement the Outlying Islands Sewerage Scheme Stage 1 Phase II works, Package J Sok Kwu Wan Sewage Treatment and Disposal Facilities (hereinafter termed the Project) under Agreement No. CE 20/96.

1.4. The submarine sewage outfall is classified as designated project under Schedule 2 Part 1, F.6 of the Environmental Impact Assessment Ordinance (EIAO). According to the draft Lamma Island Outline Zoning Plan (OZP) No. S/I-LI/4, a pumping station (P1a), some of the sewer alignments and the proposed sewage treatment works (STW) fall within Conservation Area (CA) and hence these works are also classified as designated projects under Schedule 2 Part 1, Q1 of the EIAO. Maunsell Environmental Management Consultant Ltd. was commissioned by MCAL to carry out an Environmental Impact Assessment (EIA) Study in order to assess the potential environmental impacts arising from the construction and operation phases of the Project.

Objectives of the EIA Study

1.5. The purpose of this EIA study is to assess the environmental issues arising from the construction and operation phases of the Project, and to recommend appropriate mitigation measures for all identified adverse environmental impacts.

1.6. The objectives of the EIA Study are described below:

(a) to describe the Project and associated works together with the requirements for carrying out the Project;

(b) 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 upon the Project, including both the natural and man-made environment;

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

(d) to identify and quantify the potential fisheries impacts, especially potential impacts on Sok Kwu Wan fish culture zone, associated with the Project;

(e) to identify and quantify any potential losses or damage to flora, fauna and natural habitats;

(f) to identify existing landscape and visual quality in the “study area” for the purpose of evaluating the landscape and visual impact of the Project;

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

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

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

(j) to design and specify the environmental monitoring and audit requirements necessary to ensure the implementation and the effectiveness of the environmental protection and pollution control measures adopted;

(k) to investigate the extent of side-effects of proposed mitigation measures that may lead to other forms of impacts;

(l) to identify constraints associated with the mitigation measures recommended in the study; and

(m) to identify any additional studies necessary to fulfill the objectives to the requirements of the EIA Study

The Approach

1.7. The assessment was conducted in accordance with the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) and based on information available at the time of this EIA study. Relevant reports and drawings have been reviewed and findings have been incorporated where appropriate in this EIA Report. Relevant studies to this study are listed below:

· Final Report of the Outlying Islands Sewerage Master Plan Study;

· South West New Territories Development Strategy Review;

· Territorial Development Strategy Review;

· North Lantau & Islands Development Programme;

· Rural Planning and Improvement Strategy; and

· Integrated Sludge Disposal Study.

1.8. The quantitative modelling and calculations, together with the input parameters, have been verified and agreed with the relevant government departments. Where applicable, realistic worst case scenarios have been adopted. Although the data used in the assessment have gaps, it is considered that the data is sufficient and suitable for the purpose of impact prediction. The selection, use and reliability of data used in the assessment is discussed in each of the technical assessment sections. The assumptions used in the assessment are also explained where relevant in each section.

Report Structure

1.9. The background to the Project and the objectives of this report are introduced in Section 1. Description of the Project is provided in Section 2. Sections 3 through 10 detail the results of the environmental assessment of each key subject area, covering relevant legislation, existing environmental conditions, assessment criteria and methods, and assessment findings. Sections 3 – 10 include:

Section 3:Air Quality

Section 4: Noise

Section 5: Water Quality

Section 6: Sediment Contamination

Section 7:Solid Waste

Section 8: Ecological Impact

Section 9 Fisheries Impact

Section 10: Visual and Landscape Impact

1.10. Since the EIA Study Brief does not require a heritage impact assessment (HIA) for the proposed Project, the EIA Report does not include the HIA. Nevertheless, the cultural heritage aspects of the Project have been separately conducted and the results indicate that the proposed project would not result in any adverse cultural heritage impacts.

1.11. An outline of the requirements for Environmental Monitoring and Audit (EM&A) programmes to be included in the development is discussed in Section 11. Detailed EM&A programmes are presented in a separate EM&A Manual. A detailed implementation schedule of the recommended mitigation measures are provided in Section 12. A conclusion of the whole assessment is given in Section 13.