Environmental Impact Assessment Ordinance (Cap. 499), Section 5 (7)

Environmental Impact Assessment Study Brief No. ESB-129/2005

Project Title : Harbour Area Treatment Scheme (HATS) Stage 2A

(hereinafter known as the “Project”)

Name of Applicant :      Harbour Area Treatment Scheme Division

                 Drainage Services Department

(hereinafter known as the "Applicant")

1.         BACKGROUND

            1.1       An application (No. ESB-129/2005) for an Environmental Impact Assessment (EIA) study brief under section 5(1) of the Environmental Impact Assessment Ordinance (EIAO) was submitted by the Applicant on 7 July 2005 with a Project Profile (No. PP-252/2005).

1.2       The Harbour Area Treatment Scheme (HATS, formerly known as Strategic Sewage Disposal Scheme) comprises two stages. Stage 1 involved the construction of a chemically enhanced primary treatment works at Stonecutters Island (SCI), building of a deep tunnel system to convey sewage from the Kowloon Peninsula, Tseung Kwan O, Kwai Tsing and Hong Kong Island East to the new treatment plant, and the construction of a tunnel outfall in the western harbour. The Stage 1 was fully completed and commissioned in December 2001.

1.3       The HATS Stage 2 is to intercept and treat the sewage generated from the populated areas in the northern and southwestern parts of Hong Kong Island, which currently only subject to preliminary screening before being discharged into the harbour, increasing the treatment capacity to cope with the anticipated population and economic activity growth in the harbour area, and providing a higher level of treatment for all HATS flows to fully meet the water quality objectives set for the Victoria Harbour in the long run. HATS Stage 2 is intended to be implemented in two phases, Stage 2A and Stage 2B. This study brief covers the works for Stage 2A. Scope of works for Stage 2A include the followings:

i. upgrading of existing preliminary treatment works (PTW) at North Point, Wan Chai East, Central, Sandy Bay, Cyberport, Wah Fu, Aberdeen and Ap Lei Chau on Hong Kong Island;

ii. extension of the deep tunnel network to collect and transfer sewage from the above-mentioned PTWs to Stonecutters Island for treatment and disposal;

iii. expansion of the existing chemical treatment capacity at Stonecutters Island from the present design level of 1.7 million cubic metres daily to ultimately 2.8 million cubic metres; and

iv. provision of disinfection to all HATS effluent before discharge into the harbour.

1.4       The following elements of the Project addressed in this Project Profile are classified as Designated Projects under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO).

Ÿ             Proposed pumping stations at Cyberport and Sandy Bay with an installed capacity of more than 2 000m³ per day and a boundary of which are less than 150m from an existing or planned residential area, educational institution and/or health care institution (item F3 (b)(i) of Part I of Schedule 2 of EIAO)

Ÿ             Proposed Preliminary Treatment Works (PTWs) upgrading at North Point, Wan Chai East, Central, Sandy Bay, Cyberport, Aberdeen, Wah Fu and Ap Lei Chau with an installed capacity of more than 15,000m³ per day (item F.1 of Part I of Schedule 2 of EIAO)

Ÿ             Proposed Stonecutters Island Sewage Treatment Works upgrading with an installed capacity of more than 15,000m³ per day (item F.1 of Part I of Schedule 2 of EIAO)

Ÿ Submarine sewage pipeline from Central to Stonecutters Island which has a diameter more than 1 200mm and a length more than 1 km (item F.5 of Part I of Schedule 2 of EIAO)

            1.5       Pursuant to section 5(7)(a) of the EIAO, the Director of Environmental Protection (the Director) issues this EIA study brief to the Applicant to carry out an EIA study.

            1.6      The purpose of this 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 by the Director on :

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

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

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

2.         OBJECTIVES OF THE EIA STUDY

2.1       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 Project;

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

(iii) to consider alternatives where necessary, as detailed in Section 3.3 below, with a view to avoiding and minimizing the potential environmental impacts, in particular, on sensitive receivers within the receiving water bodies; to compare the environmental benefits and dis-benefits 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 assess the level of disinfection required in order to protect the beneficial uses of the sensitive receivers identified, including the Tsuen Wan beaches;

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

(vi) to identify and quantify any potential landscape and visual impacts and to propose measures to mitigate these impacts;

(vii) to identify the negative impacts on any historical and archaeological resources and to propose measures to mitigate these impact;

(viii) 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;

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

(x) to identify, predict and evaluate the residual (i.e. after practicable mitigation) 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;

(xi) 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;

(xii) 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

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

3.         DETAILED REQUIREMENTS OF THE EIA STUDY

3.1       The Purpose

                        The purpose of this EIA study brief is to scope the key issues of the EIA study and to specify the environmental issues that are required to be reviewed and assessed in the EIA report.  The Applicant has to demonstrate in the EIA report that the criteria in the relevant sections of the Technical Memorandum on Environmental Impact Assessment Process of the Environmental Impact Assessment Ordinance (hereinafter referred to as the TM),  are fully complied with.

3.2       The Scope

              The scope of this EIA study shall cover the proposed works area shown in Figure PP-001 to PP-010 of the Project Profile (No. PP-252/2005) which are reproduced in Appendix A of this EIA Study Brief and shall cover the Project mentioned in section 1.3 above.  The EIA study shall address the likely key issues described below; and together with any other key issues identified during the course of the EIA study :

(i) the potential water quality impacts on the receiving water system(s) and the sensitive receivers including flora and fauna, arising from the discharge of treated effluent via the outfall at Stonecutters Island;

(ii) the potential water quality impacts on the receiving water system(s) and the sensitive receivers including flora and fauna, from discharge of emergency overflows from the SCISTW;

(iii) the potential water quality impacts on the receiving water system(s) and the sensitive receivers including flora and fauna, from overflow at seawall outfall of PTWs during operation stage when wet weather flows in excess of the capacity of the deep tunnel system;

(iv) the potential water quality impacts on the receiving water system(s) and the sensitive receivers including flora and fauna, due to possible temporary by-pass of sewage via the seawall outfall during the expansion of the SCISTW and the upgrading of the PTWs;

(v) with reference to the EIA study to be carried out under EIAO Application No. ESB-120/2004 as appropriate, the potential environmental impacts arising from the proposed disinfection process on the water quality and ecology;

(vi) the potential terrestrial ecological impacts caused by the Project including loss of habitats, removal of vegetation and disturbance to wildlife.

(vii) the potential noise and dust impacts arising from the construction works of the Project (in particular the drop shafts, tunnels and upgrading works of the PTWs and the SCISTW). This EIA study should also take into account any other major projects that may occur concurrently with this Project;

(viii) the potential noise and odour impacts arising from the operation of the proposed pumping stations and the upgraded PTWs and the SCISTW;

(ix) the potential landscape and visual impacts during construction and operation stages and the relevant mitigation measures to be recommended;

(x) the potential impacts on historical and archaeological resources;

(xi) the potential hazard impacts on two proposed works sites at Aberdeen and Ap Lei Chau which are located within the consultation zones of two respective Potential Hazardous Installations (PHIs); and

(xii) the potential impacts on the existing PHIs, namely the Hongkong & China Gas Company’s Gas Holder (PHI No. H4) near Aberdeen PTW and the Shell LPG Transit Depot/Bulb Domestic Supply (PHI No. H5) near Ap Lei Chau PTW arising from the construction of any drop shaft, trench or underground tunnel, etc that has the propensity to cause ground subsidence (off-site accident initiator) leading to catastrophic failure of vessels, equipment or installations within the PHIs (on-site accident).

3.3       Consideration of Alternative Treatment Methods and Construction Methods

3.3.1    Consideration of Alternative Treatment Methods

Where the EIA predicts impacts on water quality of receiving water bodies and/or impacts on ecological sensitive areas would exceed relevant criteria in the TM, the Applicant shall consider other feasible sewage treatment options for the Project, such as using alternative disinfection methods, with a view to mitigating the water quality and/or ecological impacts to within relevant criteria in the TM.  A comparison of the environmental benefits and dis-benefits of possible sewage treatment options, including alternative disinfection options, shall be made with a view to recommending the preferred option to avoid adverse environmental effects to maximum practicable extent.  Assessments on water quality impacts, including identification of potentially harmful products associated with different disinfection options should be carried out to evaluate the respective impacts on nearby sensitive receivers. Reference should be made to the EIA to be carried out under the study brief No. ESB-120/2004 on “Harbour Area Treatment Scheme (HATS) – Provision of Disinfection Facilities at Stonecutters Island” as appropriate.

3.3.2    Consideration of Alternative Construction Methods and Sequences of Works

            If the EIA predicts that the construction air, noise, water quality and odour impacts would exceed relevant criteria in the TM, the Applicant shall explore alternative construction methods, sites, transport routes, and sequences of works for the Project, taking into consideration the combined effect with respect to the severity and duration of the construction impacts to the affected sensitive receivers, with a view to avoiding prolonged adverse environmental impacts to the maximum practicable extent.  A comparison of environmental benefits and disbenefits of applying different construction methods and sequence of works shall be made.

3.3.3    Selection of Preferred Scenario

Taking into consideration of the findings in Sections 3.3.1 to 3.3.2 above, the Applicant shall provide justifications and recommend the adoption of the preferred sewage treatment method, disinfection method and construction method that will avoid or minimize adverse environmental effects arising from the Project, and adequately describe the part that environmental factors played in arriving at the final selection.

3.4       Technical Requirements

            The Applicant shall conduct the EIA study to address all environmental aspects of the activities as described in the scope as set out above.  The EIA study shall include the following technical requirements on specific impacts.

3.4.1    Air Quality Impact

3.4.1.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing air quality impacts as stated in Annexes 4 and 12 of the TM.

3.4.1.2 The study area for air quality shall be defined by a distance of 500 metres from the project boundary as shown in Appendix A to address dust control during the construction stage with consideration be given to extend the area to include areas where the air quality may be potentially affected by the Project especially areas close to the nearby access road(s) affected by construction vehicles moving to and from the construction sites. For odour impact assessment, the study area shall be extended to include all affected sensitive receivers at distances over 500m from the Project, which would be affected by the construction and operation of the Project.

3.4.1.3  The Applicant shall assess the air pollutant concentrations with reference to the relevant sections of the guidelines in Appendices B-1 to B-3 attached to this study brief, or other methodology as agreed by the Director.

3.4.1.4  The air quality impact assessments shall include the following major tasks :

(i)     Background and Analysis of Activities

(a)    Provide background information relating to air quality issues relevant to the Project, e.g. description of the types of activities of the Project that may affect air quality during both construction and operation stages, including the construction of the deep tunnel network; the upgrading of the PTWs and the expansion of the SCISTW.

(b)    Give an account, where appropriate, of the consideration/measures that had been taken into consideration in the planning of the Project to abate the air pollution impact. That is, the Applicant shall consider alternative construction methods/phasing programmes and alternative modes of operation to minimize the constructional and operational air quality impact respectively.

(c)    Present background air quality levels in the assessment area for the purpose of evaluating cumulative constructional and operational air quality impacts.

(ii)    Identification of Air Sensitive Receivers (ASRs) and Examination of Emission / Dispersion Characteristics

(a) Identify and describe existing and planned/committed ASRs that would likely be affected by the Project, including those earmarked on the relevant Outline Zoning Plans, Development Permission Area Plans, Outline Development Plans and Layout Plans.  The Applicant shall select the assessment points of the identified ASRs that represent the worst impact point of these ASRs.  A map showing the location and description such as name of buildings, their uses and height of the selected assessment points shall be given.  The separation distances of these ASRs from the nearest emission sources shall also be given.  If the Project will be carried out in phases, the Applicant shall review the odour emission impact arising from the existing, modified/expanded, temporary and new sewage treatment units on the identified ASRs for each phase.

(b)    Provide an exhaustive list of air pollutant emission sources, including any nearby emission sources which are likely to have impact related to the Project based on the analysis of constructional and operational activities in Sub-section 3.4.1.4(i) above.  Examples of construction stage emission sources include stockpiling, blasting, concrete batching, marine construction plant and vehicular movements on unpaved haul roads on site, odour emission from the modification/expansion work on existing sewage treatment units such as the existing aerated grit channels, etc. and the temporary sewage treatment units.  Examples of operational stage emission sources include exhaust emissions from all the sewage treatment units, etc.  Confirmation of validity of the assumptions and magnitude of the activities (e.g. volume of construction material handled, odour emission strength, etc.) shall be obtained from the relevant government departments/authorities and documented.

(iii)    Construction Stage Air Quality Impact

(a)    The Applicant shall follow the requirements stipulated under the Air Pollution Control (Construction Dust) Regulation to ensure that construction dust which may arise as a result of the works are controlled within the relevant standards as stipulated in Section 1 of Annex 4 of the TM.  A monitoring and audit programme for the construction stage shall be devised to verify the effectiveness of the control measures proposed so as to ensure proper construction dust control.

(b) If the Applicant anticipates that the Project will give rise to significant construction dust impacts likely to exceed recommended limits in the TM at the ASRs despite the incorporation of the dust control measures proposed in accordance with Sub-section 3.4.1.4(iii)(a) above, a quantitative assessment should be carried out to evaluate the construction dust impact at the identified ASRs.  The Applicant shall follow the methodology set out in Sub-section 3.4.1.4(v) below when carrying out the quantitative assessment.

(c) If the Applicant anticipates that the Project will give rise to significant construction stage odour impact which may arise as a result of the works such as modification/expansion of any sewage treatment units and installation of any temporary sewage treatment units to the existing PTWs and the SCISTW during the construction stage, a quantitative assessment shall be carried out to evaluate the construction odour impact at the identified ASRs. The Applicant shall follow the methodology set out in Sub-section 3.4.1.4(v) below when carrying out the quantitative assessment. A monitoring and audit programme for the construction phase impact shall be devised to verify the effectiveness of the control measures proposed so as to ensure proper construction odour control.

(iv)   Operational Stage Air Quality Impact

(a) The Applicant shall calculate the expected air pollutant concentrations, including odour, at the identified ASRs based on an assumed reasonably worst-case scenario.  The evaluation shall be based on the strength of the emission sources identified in Sub-section 3.4.1.4(ii)(b) above.  The Applicant shall follow Sub-section 3.4.1.4(v) below when carrying out the quantitative assessment.  A monitoring and audit programme for the operational stage shall be devised to verify the effectiveness of the control measures proposed so as to ensure proper operational odour control.

(v)    Quantitative Assessment Methodology

(a)    The Applicant shall apply the general principles enunciated in the modelling guidelines in Appendices B-1 to B-3 while making allowance for specific characteristics of the Project.  This specific methodology must be documented in such level of details (preferably with tables and diagrams) to allow readers of the assessment report to grasp how the model is set up to simulate the situation at hand without referring to the model input files.  Details of the calculation of emission rates of air pollutants for input to the model shall be presented in the report.  The Applicant must ensure consistency between text description and model files at every stage of submission.  In case of doubt, the Applicant should seek prior agreement from the Director on specific modelling details.

(b)    The Applicant shall identify key/representative air pollutant parameters (types of pollutants and averaging time concentration) to be evaluated and provide explanation for choosing these parameters for assessing the impact of the Project.

(c)    The Applicant shall calculate the net and cumulative air quality impact at identified ASRs and compare these results against the criteria set out in Section 1 of Annex 4 in the TM.  The predicted air quality impacts (both unmitigated and mitigated) shall be presented in the form of summary table and pollution contours, to be evaluated against the relevant air quality standards and on any effect they may have on land use implications.  Plans of a suitable scale should be used to present pollution contour to allow buffer distance requirements to be determined properly.

(vi)   Mitigation Measures for Non-compliance

The Applicant shall propose remedies and mitigating measures where predicted air quality impact exceeds the criteria set in Section 1 of Annex 4 in the TM.  These measures and any constraints on future land use planning shall be agreed with relevant government departments/authorities and documented.  The Applicant shall demonstrate quantitatively whether the resultant impacts after incorporation of the proposed mitigating measures will comply with the criteria stipulated in Section 1 of Annex 4 in the TM.

(vii)  Submission of Model Files

All input and output file(s) of the model run(s) shall be submitted to the Director in electronic format.

3.4.2    Noise Impact

            3.4.2.1             The Applicant shall follow the criteria and guidelines for evaluating and assessing noise impact as stated in Annexes 5 and 13 of the TM.

3.4.2.2 The noise impact assessment shall include the following :

            (i)         Determination of Assessment Area

The area for the noise impact assessment shall generally include all areas within 300m from the project boundary as shown in Appendix A with consideration be given to extend the area to include areas that may be potentially affected by the Project especially areas close to the nearby access road(s) affected by construction vehicles moving to and from the construction sites.  Subject to the agreement of the Director, the assessment area could be reduced accordingly if the first layer of noise sensitive receivers, closer than 300m from the outer project limit, provides acoustic shielding to those receivers at further distance behind.

            (ii)        Provision of Background Information and Existing Noise Levels

  The Applicant shall provide all background information relevant to the Project, e.g. relevant previous or current studies.  Unless involved in the planning standards, e.g. those for planning of fixed noise sources, no existing noise levels are particularly required.

            (iii)       Identification of Noise Sensitive Receivers

 (a)      The Applicant shall refer to Annex 13 of the TM when identifying the noise sensitive receivers (NSRs).  The NSRs shall include all existing NSRs and all planned/committed noise sensitive developments and uses earmarked on the relevant Outline Zoning Plans, Outline Development Plans and Layout Plans.

            (b)        The Applicant shall select assessment points to represent all identified NSRs for carrying out quantitative noise assessment described below.  The assessment points shall be agreed with the Director prior to the quantitative noise assessment.  A map showing the location and description such as name of building, use, and floors of each and every selected assessment point shall be given.  For planned noise sensitive land uses without committed site layouts, the Applicant should use the relevant planning parameters to work out site layouts for noise assessment purpose.

            (iv)       Provision of an Emission Inventory of the Noise Sources

                                    The Applicant shall provide an inventory of noise sources (e.g. construction equipment for assessment of construction noise (both air-borne and structure-borne noise) associated with tunnelling works; and plant/equipment for operational noise assessment).  Confirmation of the validity of the inventory shall be obtained from the relevant government departments/authorities.

            (v)        Construction Noise Assessment

                                    (a)                    The Applicant shall carry out assessment of noise impact from construction (excluding percussive piling) of the Project during day time, i.e. 7 a.m. to 7 p.m., on weekdays other than general holidays in accordance with the methodology stipulated in paragraphs 5.3. and 5.4 of Annex 13 of the TM.  The criteria in Table 1B of Annex 5 of the TM shall be adopted in the assessment.

            (b)        To minimize the construction noise impact, alternative construction methods to replace percussive piling shall be proposed as far as practicable.  In case blasting cannot be avoided, it should be carried out, as far as practicable, outside the sensitive hours of 7 p.m. to 7 a.m. on Monday to Saturday and any time on a general holiday, including Sunday. For blasting that must be carried out during the above-mentioned sensitive hours, the noise impact in associated with the removal of debris and rocks should be fully assessed and adequate mitigation measures should be recommended to reduce the noise impact as appropriate. For tunnelling, noise impact (including air-borne noise and structure-borne noise) associated with the operation of powered mechanical equipment, in particular, tunnel boring machine/raise boring machine or equivalent, shall be assessed.

            (c)        If the unmitigated construction noise levels are found exceeding the relevant criteria, the Applicant shall propose practicable direct mitigation measures (including movable barriers, enclosures, quieter alternative methods, re-scheduling and restricting hours of operation of noisy task) particularly at the open-cut area(s) and the tunnel portal(s) to minimize the impact.  If the mitigated noise levels still exceed the relevant criteria, the duration of the noise exceedance shall be given.

(d)      In case the Applicant would like to evaluate whether construction works in restricted hours as defined under the Noise Control Ordinance (NCO) are feasible or not in the context of programming construction works, reference should be made to the relevant technical memoranda issued under the NCO. Regardless of the results of the construction noise impact assessment for restricted hours, the Noise Control Authority will process the Construction Noise Permit (CNP) application, if necessary, based on the NCO, the relevant technical memoranda issued under the NCO, and the contemporary conditions/situations. This aspect should be explicitly stated in the noise chapter and the conclusions and recommendations chapter in the EIA report.

            (vi)       Operational Noise Assessment on Fixed Noise Sources

                        (a)        Assessment of Fixed Source Noise Levels

The Applicant shall calculate the expected noise using standard acoustics principles.  Calculations for the expected noise shall be based on assumed plant inventories and utilization schedule for the worst case scenario. The Applicant shall calculate the noise levels taking into account of correction of tonality, impulsiveness and intermittency in accordance with the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites.

(b)        Presentation of Noise Levels

The Applicant shall present the existing and future noise levels in Leq (30 min) at the NSRs at various representative floor levels (in m P.D.) on tables and plans of suitable scale.

A quantitative assessment at the NSRs for the proposed fixed noise source(s) shall be carried out and compared against the criteria set out in Table 1A of Annex 5 of the TM.

(c)        Proposals for Noise Mitigation Measures

The Applicant shall propose direct technical remedies within the project limits in all situations where the predicted noise level exceeds  the criteria set out in Table 1A of Annex 5 of the TM to protect the affected NSRs.

            (vii)      Assessment of Side Effects and Constraints

                                    The Applicant shall identify, assess and propose means to minimize any side effects and to resolve any potential constraints due to the inclusion of any recommended direct technical remedies.

            (viii)      Evaluation of Constraints on Planned Noise Sensitive Developments/Landuses

                                    For planned noise sensitive uses which will still be affected even with all practicable direct technical remedies in place, the Applicant shall propose, evaluate and confirm the practicality of additional measures within the planned noise sensitive uses and shall make recommendations on how these noise sensitive uses will be designed for the information of relevant parties.

                                    The Applicant shall take into account agreed environmental requirements / constraints identified by the study to assess the development potential of concerned sites which shall be made known to the relevant parties.

3.4.3    Water Pollution

3.4.3.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing water pollution as stated in Annexes 6 and 14 of the TM.

3.4.3.2 The study area for this water quality assessment shall cover the following Water Control Zones as designated under the Water Pollution Control Ordinance: North Western, Western Buffer, Victoria Harbour, Eastern Buffer, Junk Bay and Southern. This study area shall be extended to include major emission sources that may have a bearing on the environmental acceptability of the Project. Sensitive receivers including habitats of species of conservation importance, area of fisheries interest, fish culture zone, bathing beaches and secondary contact recreation zones and sea water intakes shall be addressed in the water quality assessment.

3.4.3.3 The Applicant shall identify and analyse the physical, chemical and biological disruptions of marine, fresh water or ground water system(s), catchment area(s), storm water pipeline and coastal water arising from construction and operation of the Project. Depending on the disinfection technology to be adopted and with reference to the EIA to be carried out under the study brief No. ESB-120/2004 on “Harbour Area Treatment Scheme (HATS) – Provision of Disinfection Facilities at Stonecutters Island” as appropriate, the Applicant shall clearly explain the effects of potential toxicity of chlorinated effluents and dechlorination agents, the water quality implications due to application of hypochlorite and dechlorination agents, and mitigation measures to be taken to avoid adverse impacts of chlorination and dechlorination.

3.4.3.4 The Applicant shall predict, quantify and assess any water quality impacts arising from construction and operation of the Project on the water system(s) and the sensitive receivers by mathematical modelling. The water quality impacts shall include changes in hydrology, flow regime, sediment erosion and deposition pattern, water and sediment quality, downstream salinity profile and effects on the flora and fauna. The mathematical modelling requirements are set out in Appendix C to this Study Brief.

3.4.3.5 The Applicant shall take into account Stage 1, Stage 2A and Stage 2B of the HATS in the assessment. The Applicant shall have regard to the content, frequency, duration, volume and flow rate of the discharges and its pollutant and sediment loading. The applicant shall assess the water quality impacts associated with the emergency overflow of the whole HATS system. The applicant shall also assess the water quality impacts arising from the necessary temporary discharge of sewage via emergency or seawall outfall during construction stage, and immediately prior to and/or during the early phase of the commissioning of the upgraded sewage treatment facilities and preliminary treatment works. Essentially the assessment shall address the following:

(i)      collection and review of background information on the existing and planned water system(s) and their respective catchments and sensitive receivers which might be affected by the Project during different stages;

(ii)     characterization of water and sediment quality of the water system(s) and respective catchments and sensitive receivers which might be affected by the Project based on existing information or information collected from appropriate site surveys/tests;

(iii)    identification and analysis of the existing and planned future activities and beneficial uses related to the water system(s) and identification of the water sensitive receivers. The Applicant shall refer to those developments and uses indicated on the relevant Outline Zoning Plans, Outline Development Plans and Layout Plans;

(iv)    identification of pertinent water and sediment quality objectives, criteria and standards for the water system(s) and the sensitive receivers in Sub-section 3.4.3.5(iii) above. Reference shall be made to the set of water quality criteria established under the Environmental and Engineering Feasibility Assessment Studies in relation to the Way Forward of the HATS;

(v)     review of the different stages of the Project to identify any alteration of existing shoreline or bathymetry, flow regimes, ground water levels and catchment types or areas;

(vi)    identification and quantification of the existing and committed water and sediment pollution sources and loading, including point and non-point discharges to surface water runoff, through site investigation and tests, which are to be generated by the Project and discharged to marine waters and existing and planned drainage systems;

(vii)    evaluation and prediction of the effluent characteristics based on provision of disinfection facilities at SCISTW to cover the intermediate and final operation stages of the Project. The Applicant shall predict the effluent characteristics by making reference to the wastewater characteristics, the performance of the Chemical Enhanced Primary Treatment (CEPT) process at SCISTW, the proposed disinfection facilities, chemical dosages and contact time, the findings of the previous studies, and additional sampling and tests. Parameters shall include pH value, ammonia, sulphite (if sodium bisulphite is used as dechlorination agent), and total residual chlorine and chlorination by-products (if chlorination is considered as an option of disinfection). The Applicant shall identify contaminants that are of concern, and shall arrange to carry out whole effluent toxicity tests over a range of dilution using ambient seawater, and using different biological species;

(viii) establishment and provision of a pollution load inventory on the quantities and characteristics of the existing and future water pollution sources in sub-section 3.4.3.5(vi). Field investigation and laboratory tests shall be conducted if the information is not available;

(ix) analysis on the provision and adequacy of existing and planned future wastewater treatment facilities in terms of capacity and level of treatment to reduce pollution arising from both point and non-point discharges identified in Sub-section 3.4.3.5(vi) above. The need for any lagoons and grease/oil traps and other mitigation measures shall be analysed and specific measures recommended;

(x) assessment of the cumulative impacts due to other related concurrent and planned projects, activities or pollution sources along the identified water system(s) and sensitive receivers that may have a bearing on the environmental acceptability of the Project through mathematical modelling. This shall include the potential cumulative operational water quality impact arising from other sewage treatment works and once-through cooling water systems;

(xi) review of the previous studies and the information from additional sampling and tests and assessment of the adverse ecological effects that may result from exposure to toxic substances due to effluent discharges, and the potential human health risks associated with ingestion of and contact with contaminated seawater during swimming or engaging in other water related activities and with the consumption of potentially contaminated seafood. The approach and methodologies shall involve:

(a)   Problem formulation - identification of the perceived risks and values of the resources to be protected and establishment of the objectives, scope and focus of the assessment;

(b)   Characterization of exposure and ecological effects - identification of the toxic contaminants of concern; the characteristics of the communities potentially at risk; assessment endpoint; prediction of the spatial and temporal distribution of the toxic substances, and identification and quantification of the adverse effects on the communities potentially at risk from exposure to the toxic substances in marine water due to the effluent discharge;

(c)   Toxicity assessment and risk assessment - characterization of the ecological or human health effects of each identified substance on the exposed receptors, and evaluation of the likelihood of adverse ecological and public health effects associated with exposure. The ecological significance of the risk shall be evaluated with consideration of the types and magnitudes of the effects, their spatial and temporal patterns, and the likelihood of recovery. A summary of the assumptions used, the scientific uncertainties, and the strengths and weaknesses of the analyses shall be provided;

(xii)     proposal of infrastructure upgrading or provision, water pollution prevention and mitigation measures to be implemented during different operational stages so as to reduce water quality impacts to within acceptable levels of standards; and

(xiii)    proposal of mitigation measures to avoid or minimize the impacts identified above. The residual impacts on the water system(s) and the sensitive receivers with regard to the relevant water quality objectives, criteria, standards or guidelines shall be assessed and quantified using mathematical models set out in Appendix C of this study brief.

3.4.4    Waste Management Implications

3.4.4.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing waste management implications as stated in Annexes 7 and 15 of the TM respectively.

3.4.4.2 The assessment of waste management implications shall cover the following:

(i)        Analysis of Activities and Waste Generation

                        The Applicant shall identify the quantity, quality and timing of the waste and chemical waste arising as a result of the construction and operation activities of the Project, based on the sequence and duration of these activities. The Applicant shall adopt design, general layout, construction methods and programme to minimize the generation of public fill/inert C&DM and maximise the use or reuse of public fill/inert C&DM for other construction works and landfill should be considered as the last option.

(ii)        Proposal for Waste Management

(a) Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation, on-site or off-site re-use and recycling shall be evaluated.  Measures that can be taken in the planning and design stages e.g. by modifying the design approach and in the construction stage for maximizing waste reduction shall be separately considered.

(b) After considering the opportunities for reducing waste generation and maximizing re-use, the types and quantities of the wastes required to be disposed of as a consequence shall be estimated and the disposal options for the wastes shall be described in detail. The disposal options recommended for each type of wastes shall take into account the result of the assessment in item (c) below.  The EIA report shall also state clearly the transportation routings and the frequency of the trucks/ vessels involved, any barging point or conveyor system to be used, the stockpiling areas and the disposal outlets for the wastes identified; and

(c) The impact caused by handling (including stockpiling, labelling, packaging & storage), collection, transportation and disposal of wastes shall be addressed in detail and appropriate mitigation measures shall be proposed. This assessment shall cover the following areas :

-          potential hazard;

                                     -          air and odour emissions;

                                     -          noise;

                                     -          wastewater discharge;

- public transport; and

- landscape and visual impacts, if any.

(iii)       Waste Management Plan

If the construction method(s) adopted will lead to the generation of significant amount of wastes material, the Applicant shall, based on the assessment in sub-sections 3.4.4.2 (i) to (ii) above, include in the EIA report a Waste Management Plan specifying, where appropriate, the following elements to ensure that the potential environmental impacts will be avoided or minimized :

(a)       measures on how to maximize the waste(s) reduction;

(b)       quantity and nature of the waste(s) to be generated;

(c)        how, when and where waste(s) will be generated, stored, reused, recycled and disposed on-site/off-site; and

(d)       their disposal mean(s), route(s) and final destination(s) inside the HKSAR boundary and outside the HKSAR boundary, which may have potential cumulative impacts to the environment of the HKSAR.

To cater for uncertainties in waste arising estimates, sites available for waste disposal, a scenarios approach may be adopted in preparing the Waste Management Plan.

3.4.5    Ecological Impact (Both Terrestrial and Aquatic)

3.4.5.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing ecological impact as stated in Annexes 8 and 16 of the TM.

3.4.5.2 The assessment area for the purpose of terrestrial ecological assessment shall include all areas within 500 m distance from the site boundary of the land-based works area of which the flora, fauna and other components of the ecological habitats are likely impacted by the Project such as the works at Sandy Bay, Cyberport and Aberdeen.  The assessment area for the purpose of marine ecological assessment shall be the same as the assessment area for water quality impact assessment in Section 3.4.3.2, or the area likely to be impacted by the Project, including areas at the vicinity of the outfalls.

3.4.5.3 In the ecological impact assessment, the Applicant shall examine the flora, fauna and other components of the ecological habitats within the assessment area.  The aim shall be to protect, maintain or rehabilitate the natural environment.  In particular, the Project shall avoid impacts on recognized sites of conservation importance (e.g. Marine Parks) and other ecological sensitive areas and species. The assessment shall identify and quantify as far as possible the potential ecological impacts associated with the Project.

3.4.5.4 The assessment shall include the following major tasks :

            (i)         review the findings of relevant studies and collate all the available information regarding the ecological characters of the assessment area;

            (ii)        evaluate the information collected and identify any information gap relating to the assessment of potential ecological impacts to the terrestrial and aquatic environment;

(iii) if any information gap is identified in (ii) above, carry out necessary field surveys, the duration of which shall at least cover four months, and investigations including tree surveys to verify the information collected, fill the information gaps identified and fulfil the objectives of the EIA study;

(iv) where field survey is found necessary and has been conducted in accordance with (iii) above, review the adequacy of the field survey and recommend, with full justifications, whether further field survey is required, having regard to the information available from previous studies and the results of the field survey conducted for this Project;

(v) establish the general ecological profile and describe the characteristics of each habitat found; major information to be provided shall include :

                        (a)        description of the physical environment;

                        (b)        habitat maps of suitable scale (1:1000 to 1:5000) showing the types and locations of habitats in the assessment area;

                        (c)        ecological characteristics of each habitat type such as size, vegetation type, species present, dominant species found, species diversity and abundance, community structure, inter-dependence of the habitats and species, and presence of any features of ecological importance;

                        (d)        representative colour photos of each habitat type and any important ecological features identified;

                        (e)        species found that are rare, endangered and/or listed under local legislation, international conventions for conservation of wildlife/ habitats or red data books;

            (vi)       investigate and describe the existing wildlife uses of various habitats with special attention to those wildlife groups and habitats with conservation interests; including woodlands, natural coastlines, White-bellied Sea Eagle, corals, marine benthic communities, marine mammals, horseshoe crabs, intertidal habitats and any other habitats and wildlife groups identified as having special conservation interests by this EIA study;

            (vii)      identify and describe all recognized sites of conservation importance and ecological sensitive receivers including sensitive elements of marine, subtidal, and intertidal communities/habitats in the project site and the assessment area and assess whether or not these will be potentially affected directly or indirectly by the Project;

            (viii)      using suitable methodology, identify and quantify as far as possible any direct, indirect, on-site, off-site, primary, secondary and cumulative ecological impacts such as destruction of habitats, reduction of species abundance/diversity, loss of feeding grounds, reduction of ecological carrying capacity and habitat fragmentation, and in particular the following :

(a)        Habitat loss and disturbance to wildlife during construction stage;

(b)       deterioration of environmental qualities (e.g. water quality) and subsequent impacts to the biological communities during operation stage; and

(c)        impacts of the proposed disinfection process and the potentially harmful products associated with the disinfection on ecological sensitive receivers, such as marine mammals.

            (ix)       evaluate the significance and acceptability of the ecological impacts identified using well-defined criteria;

            (x)        recommend all possible alternatives (such as modifications of layout and design) and practicable mitigation measures to avoid, minimize and/or compensate for the adverse ecological impacts identified;

            (xi)       evaluate the feasibility and effectiveness of the recommended mitigation measures and define the scope, type, location, implementation arrangement, subsequent management and maintenance of such measures;

            (xii)      determine and quantify as far as possible the residual ecological impacts after implementation of the proposed mitigation measures;

            (xiii)      evaluate the severity and acceptability of the residual ecological impacts using well-defined criteria.  If off-site mitigation measures are considered necessary to mitigate the residual impacts, the guidelines and requirements laid down in the PELB Technical Circular No. 1/97 shall be followed; and

            (xiv)     review the need for and recommend any ecological monitoring programme required.

3.4.6    Fisheries Impact

3.4.6.1  The Applicant shall follow the criteria and guidelines for evaluating and assessing fisheries impact as stated in Annexes 9 and 17 of the TM.

3.4.6.2  The assessment area for fisheries impact assessment shall in general be the same as for water quality impact assessment stated in section 3.4.3.2, and any areas likely to be impacted by the Project, including the Ma Wan, Sok Kwu Wan, Lo Tik Wan, Cheung Sha Wan, Po Toi and Tung Lung Chau fish culture zones.

3.4.6.3  The assessment area shall cover any potential impact for the options as derived under sub-clause 3.3.2 of this Brief on both capture and culture fisheries, during the construction and operation phase. Existing information regarding the study area shall be reviewed. Based on the review results, the study shall identify data gap and determine if there is any need for field surveys. If field surveys are considered necessary, the study shall recommend methodology, duration and timing for the field surveys.

3.4.6.4  The fisheries impact assessment shall include the following tasks:

(i)      description of the physical environmental background;

(ii)     description and quantification of the existing capture and culture fisheries activities;

(iii)    description and quantification of the existing fisheries resources (e.g. major fisheries products and stocks);

(iv)    identification of parameters (e.g. water quality parameters) and areas that will be affected;

(v)     identification and quantification of any direct / indirect and onsite / offsite impacts of fisheries;

(vi)    evaluation of impacts and make recommendations for any environmental mitigation measures with details on justification, description of scope and programme, feasibility as well as staff and financial implications including those related to subsequent management and maintenance requirements of the proposals; and

(vii)   review of the need for monitoring and, if necessary, recommend a monitoring and auditing programme.

3.4.7    Landscape and Visual Impact

3.4.7.1  The Applicant shall follow the criteria and guidelines as stated in Annexes 10 and 18 of the TM for evaluating and assessing visual impacts of any above ground structures associated with the Project and localised landscape impacts within the sites and works areas due to the Project. Visual and landscape impacts during both the construction and the operation phases shall be assessed.

3.4.7.2  Description of the visual compatibility of the Project with the surrounding and the planned setting, and its obstruction and interference with key views of the adjacent areas; and the severity of visual impacts in terms of distance, nature and number of sensitive receivers shall be identified.  The visual impacts of the Project with and without mitigation measures shall be included so as to demonstrate the effectiveness of the proposed mitigation measures.

3.4.7.3  The Applicant shall recommend mitigation measures to minimize the adverse effects identified above, including the provision of a landscape design to retain existing vegetation, transplanting of mature trees, provision of screen planting, re-vegetation of disturbed land, compensatory planting, provisioning and reprovisioning of amenity areas and open spaces, design of structures, provision of finishes to structures, colour scheme and texture of material used, and any measures to mitigate the disturbance of the existing land use.  Presentation of perspective drawings, plans and section/elevation diagrams, photomontage from key vantage points taken for all proposed new permanent above ground structures which are substantial in size and scale (such as pumping station and shaft connection chamber) in the existing and planned urban setting and/or located at visually sensitive areas such as waterfront, illustrating the effectiveness of visual impact mitigation measures shall be included.

3.4.8    Hazard To Life

3.4.8.1The Applicant shall follow the criteria for evaluating hazard to life as stated in Annexes 4 and 22 of the TM in conducting hazard assessment.

3.4.8.2 The Applicant shall carry out hazard assessment since the proposed work sites at Aberdeen and Ap Lei Chau are located within the consultation zone of two respective Potential Hazardous Installations (PHI), namely the Hongkong & China Gas Company’s Gas Holder (PHI No. H4) and the Shell LPG Transit Depot/Bulb Domestic Supply (PHI No. H5). The assessment shall include the followings:

(i)        assess the risks associated with all aspects of the construction and operation of the Project ;

(ii)        assess the hazards associated with the storage and use of any other dangerous goods or hazardous activities present on site;

(iii)       ascertain whether the overall risks posed by the activities of the Project are acceptable, taking into account the risk guidelines set out in section 4.4 of  Chapter 11 of the Hong Kong Planning Standards & Guidelines;

(iv)       recommend mitigation measures where the risk is considered in the ALARP (As Low As Reasonably Practicable) region or above, and to quantify the reduction in risk achievable by these means; and

(v)       recommend measures, including relocation of works area(s), that would prevent accidental damage to the adjacent PHIs and their associated pipelines during construction and operation of the Project.

3.4.8.3  The Applicant shall expand the scope of the hazard assessment if there is overnight storage of explosives on site, and the storage location could adversely impact on the populated areas or any PHIs nearby. The scope shall include :

i)          identification of all credible and applicable hazardous scenarios associated with the on-site transport, storage and use of explosives for blasting operations;

ii)        execution of a Quantitative Risk Assessment to determine risks to the off-site population in both individual and societal terms;

iii)       comparison of individual and societal risks with the Criteria for Evaluating Hazard to Life (Risk Guidelines) stipulated in Annex 4 of the TM and to determine the acceptability of the assessed risk;

iv) identification and assessment of practicable and cost effective risk mitigation measures to demonstrate compliance with the Risk Guidelines; and.

v) the methodology of hazard assessment shall be agreed and approved by the Director prior to commencing the detailed studies.

3.4.8.4 If chlorination is proposed as the disinfection technology, a hazard assessment of manufacture, storage, use and transport of dangerous goods (e.g. hydrogen, hypochlorite, dechlorination agent,  hydrochloric acid, caustic and ferric chloride) shall be carried out following the criteria for evaluating hazard to life as stated in Annexes 4 and 22 of the TM and include the following in the assessment:

(i)        identification of all credible and applicable hazardous scenarios associated with the on-site transport, manufacture, storage, and use of dangerous goods;

(ii)       execution of a Quantitative Risk Assessment to determine risks to the off-site population in both individual and societal terms;

(iii)      comparison of individual and societal risks with the Criteria for Evaluating Hazard to Life (Risk Guidelines) stipulated in Annex 4 of the TM and to determine the acceptability of the assessed risk;

(iv) identification and assessment of practicable and cost effective risk mitigation measures to demonstrate compliance with the Risk Guidelines; and

(v) the methodology of hazard assessment shall be approved by the Director prior to commencing the detailed studies. Reference shall be made to the EIA to be carried out under the study brief No. ESB-120/2004 on “Harbour Area Treatment Scheme (HATS) – Provision of Disinfection Facilities at Stonecutters Island” as appropriate.

3.4.9    Cultural Heritage Impact

3.4.9.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing cultural heritage impacts as stated in Annexes 10 and 19 of the TM.

3.4.9.2 The cultural heritage impact assessment shall include built heritage impact assessment and marine archaeological impact assessment.

3.4.9.3 Built heritage impact assessment

            The built heritage impact assessment shall include the following:

(i) The Applicant shall identify all built heritage sites that might be adversely affected by the impacts due to the construction activities of the Project on Stonecutters Island. The inventory shall include pre-1950 buildings and structures, post-1950 buildings and structures of high architectural and historical significance, historic landscape features and graves;

(ii) the Applicant shall assess the extent to which those built heritage sites might be directly and indirectly affected and recommend possible alternatives (such as modification of layout and design of the Project) and practicable monitoring and mitigation measures to be agreed with the Director to avoid or keep the adverse impacts on the built heritage sites to be minimum. Besides, a checklist including all the affected built heritage sites, impacts identified, recommended mitigation measures as well as the implementation agent and period shall also be included in the EIA report;

(iii) in case where the sources of information prove to be inadequate or where the project area has not been adequately studied before, field surveys and site investigations shall be conducted to assemble the necessary data. The assessment study on built heritage shall be conducted by qualified persons with proven records to historical building research works in Hong Kong;

(iv) the information of all the identified historic buildings and structures including their ownership, historical background, 1:1000 scale location plans, photographs and the like together with the nearby work areas shall be provided.

3.4.9.4 Marine Archaeological Impact Assessment

The Applicant shall engage a qualified marine archaeologist to review available information to identify whether there is any possible existence of sites or objects of cultural heritage, for example shipwreck, within any seabed that will be affected by the marine works of the Project. The result of the review shall be presented as a written report and charts. If possible existence of sites or objects of cultural heritage are found, a Marine Archaeological Investigation (MAI) shall be required. The MAI shall be carried out by a qualified marine archaeologist who shall obtain a Licence from the Antiquities Authority under the provision of the Antiquities and Monuments Ordinance (Cap.53). The requirements of the MAI are set out in Appendix D of this EIA study brief.

3.4.10  Summary of Environmental Outcomes

            The EIA report shall contain a summary of the key environmental outcomes arising from the EIA study, including the population and environmentally sensitive areas protected, environmentally friendly designs recommended, key environmental problems avoided, compensation areas included and the environmental benefits of environmental protection measures recommended.

3.4.11     Environmental Monitoring and Audit (EM&A) Requirements

3.4.11.1  The Applicant shall identify and justify in the EIA study whether there is any need for EM&A activities during construction and operation phases of the Project and, if affirmative, to define the scope of EM&A requirements for the Project.

3.4.11.2  Subject to confirmation of EIA findings, the Applicant shall comply with requirements as stipulated in Annex 21 of the TM. The Applicant shall also propose real-time reporting of monitoring data for the Project through a dedicated internet website.

3.4.11.3  The Applicant shall prepare a project implementation schedule (in the form of a checklist as shown in Appendix E to this EIA study brief) containing all the EIA study recommendations and mitigation measures with reference to the implementation programme.

4.         DURATION OF VALIDITY

4.1       The Applicant shall notify the Director of the commencement of the EIA study. If the EIA does not commence within 36 months after the date of issue of this EIA study brief, the Applicant shall apply to the Director for a fresh EIA study brief before commencement of the EIA study.

5.         REPORT REQUIREMENTS

5.1       In preparing the EIA report, the Applicant shall refer to Annex 11 of the TM for the contents of an EIA report. The applicant shall also refer to Annex 20 of the TM, which stipulates the guidelines for the review of an EIA report.

5.2       The Applicant shall supply the Director with the following number of copies of the EIA report and the executive summary:

(i) 50 copies of the EIA report in English and 50 copies of the executive summary (each bilingual in both English and Chinese) as required under section 6(2) of the EIAO to be supplied at the time of application for approval of the EIA report.

(ii) when necessary, addendum to the EIA report and the executive summary submitted in (i) above as required under section 7(1) of the EIAO, to be supplied upon advice by the Director for public inspection.

(iii) 20 copies of the EIA report in English and 50 copies of the executive summary (each bilingual in both English and Chinese) with or without Addendum as required under section 7(5) of the EIAO, to be supplied upon advice by the Director for consultation with the Advisory Council on the Environment.

            5.3       The Applicant shall, upon request, make additional copies of the above documents available to the public, subject to payment by the interested parties for full printing costs.

5.4       In addition, to facilitate the public inspection of the EIA Report via the EIAO Internet Website, the applicant shall provide electronic copies of both the EIA Report and the Executive Summary Report prepared in HyperText Markup Language (HTML) (version 4.0 or later) and in Portable Document Format (PDF version 4.0 or later), unless otherwise agreed by the Director.  For the HTML version, a content page capable of providing hyperlink to each section and sub-section of the EIA Report and the Executive Summary Report shall be included in the beginning of the document. Hyperlinks to all figures, drawings and tables in the EIA Report and Executive Summary shall be provided in the main text from where the respective references are made. All graphics in the report shall be in interlaced GIF format unless otherwise agreed by the Director.

            5.5       The electronic copies of the EIA report and the Executive Summary shall be submitted to the Director at the time of application for approval of the EIA Report. 

5.6       When the EIA Report and the Executive Summary are made available for public inspection under s.7(1) of the EIA Ordinance, the content of the electronic copies of the EIA Report and the Executive Summary must be the same as the hard copies and the Director shall be provided with the most updated electronic copies.

5.7 To promote environmentally friendly and efficient dissemination of information, both hardcopies and electronic copies of future EM&A reports recommended by the EIA study shall be required and their format shall be agreed by the Director.

5.8 To facilitate public involvement in the EIA process, the applicant shall produce 3-dimensional electronic visualisations of the major findings and elements of the EIA report, including baseline environmental information, the environmental situations with and without the Project, key mitigated and unmitigated environmental impacts, and key recommended environmental mitigation measures so that the public can understand the Project and the associated environmental issues. The visualisations shall be based on the EIA report and released to the public. The visualisations shall be submitted in CD-ROM or other suitable means agreed with the Director in commonly readable formats. Unless otherwise advised or agreed by the Director, the number of copies of CD-ROM required shall be the same as that for EIA reports under Section 5.2.

6.         OTHER PROCEDURAL REQUIREMENTS

6.1       If there is any change in the name of Applicant for this EIA study brief during the course of the EIA study, the Applicant must notify the Director immediately.

            6.2       If there is any key change in the scope of the Project mentioned in Section 1.3 of this EIA study brief and in Project Profile No. PP-252/2005, the Applicant must seek confirmation from the Director in writing on whether or not the scope of issues covered by this EIA study brief can still cover the key changes, and the additional issues, if any, that the EIA study must also address.  If the changes to the Project fundamentally alter the key scope of the EIA study brief, the Applicant shall apply to the Director for another EIA study brief afresh.

--- END OF EIA STUDY BRIEF ---

August 2005

Environmental Assessment Division

Environmental Protection Department

Appendix A

Figures

Appendix B-1

Guidelines on Choice of Models and Model Parameters

[The information contained in this Appendix is only meant to assist the Applicant in performing the air quality assessment.  The Applicant must exercise professional judgment in applying this general information for the Project.]

1.    Introduction

1.1       To expedite the review process by the Authority and to assist project proponents or environmental consultants with the conduct of air quality modelling exercise which are frequently called for as part of environmental impact assessment studies, this paper describes the usage and requirements of a few commonly used air quality models.

2. Choice of Models

2.1       The models which have been most commonly used in air quality impact assessments, due partly to their ease of use and partly to the quick turn-around time for results, are of Gaussian type and designed for use in simple terrain under uniform wind flow. There are circumstances when these models are not suitable for ambient concentration estimates and other types of models such as physical, numerical or mesoscale models will have to be used. In situations where topographic, terrain or obstruction effects are minimal between source and receptor, the following Gaussian models can be used to estimate the near-field impacts of a number of source types including dust, traffic and industrial emissions.

Model Applications

            FDM                      for evaluating fugitive and open dust source impacts (point, line and area sources)

            CALINE4              for evaluating mobile traffic emission impacts (line sources)

            ISCST3                 for evaluating industrial chimney releases as well as area and volumetric sources (point, area and volume sources); line sources can be approximated by a number of volume sources.

            These frequently used models are also referred to as Schedule 1 models (see attached list).

2.2 Note that both FDM and CALINE4 have a height limit on elevated sources (20 m and 10m, respectively). Source of elevation above these limits will have to be modelled using the ISCST3 model or suitable alternative models. In using the latter, reference should be made to the 'Guidelines on the Use of Alternative Computer Models in Air Quality Assessment' in Appendix B-3.

2.3 The models can be used to estimate both short-term (hourly and daily average) and long-term (annual average) ambient concentrations of air pollutants. The model results, obtained using appropriate model parameters (refer to Section 3) and assumptions, allow direct comparison with the relevant air quality standards such as the Air Quality Objectives (AQOs) for the relevant pollutant and time averaging period.

3.         Model Input Requirements

3.1       Meteorological Data

3.1.1    At least 1 year of recent meteorological data (including wind speed, wind direction, stability class, ambient temperature and mixing height) from a weather station either closest to or having similar characteristics as the study site should be used to determine the highest short-term (hourly, daily) and long-term (annual) impacts at identified air sensitive receivers in that period. The amount of valid data for the period should be no less than 90 percent.

3.1.2    Alternatively, the meteorological conditions as listed below can be used to examine the worst case short-term impacts:

Day time:      stability class D; wind speed 1 m/s (at 10m height); worst-case wind angle; mixing height 500 m

Night time:    stability class F; wind speed 1 m/s (at 10m height); worst case wind angle; mixing height 500 m

            This is a common practice with using the CALINE4 model due to its inability to handle lengthy data set.

3.1.3    For situations where, for example, (i) the model (such as CALINE4) does not allow easy handling of one full year of meteorological data; or (ii) model run time is a concern, the followings can be adopted in order to determine the daily and annual average impacts:

(i) perform a frequency occurrence analysis of one year of meteorological data to determine the actual wind speed (to the nearest unit of m/s), wind direction (to the nearest 10^o) and stability (classes A to F) combinations and their frequency of occurrence;

(ii) determine the short term hourly impact under all of the identified wind speed, wind direction and stability combinations; and

(iii) apply the frequency data with the short term results to determine the long term (daily / annual) impacts.

Apart from the above, any alternative approach that will capture the worst possible impact values (both short term and long term) may also be considered.

3.1.4    Note that the anemometer height (relative to a datum same for the sources and receptors) at which wind speed measurements were taken at a selected station should be correctly entered in the model. These measuring positions can vary greatly from station to station and the vertical wind profile employed in the model can be grossly distorted from the real case if incorrect anemometer height is used. This will lead to unreliable concentration estimates.

3.1.5    An additional parameter, namely, the standard deviation of wind direction,  σ_Θ, needs to be provided as input to the CALINE4 model. Typical values ofσ_Θ range from 12^o for rural areas to 24^o for highly urbanised areas under 'D' class stability. For semi-rural such as new development areas, 18^o is more appropriate under the same stability condition. The following reference can be consulted for typical ranges of standard deviation of wind direction under different stability categories and surface roughness conditions.

Ref.(1): Guideline On Air Quality Models (Revised), EPA-450/2-78-027R, United States Environmental Protection Agency, July 1986.

3.2       Emission Sources

            All the identified sources relevant to a process plant or a study site should be entered in the model and the emission estimated based on emission factors compiled in the AP-42 (Ref. 2) or other suitable references. The relevant sections of AP-42 and any parameters or assumptions used in deriving the emission rates (in units g/s, g/s/m or g/s/m²) as required by the model should be clearly stated for verification. The physical dimensions, location, release height and any other emission characteristics such as efflux conditions and emission pattern of the sources input to the model should also correspond to site data.

            If the emission of a source varies with wind speed, the wind speed-dependent factor should be entered.

Ref.(2): Compilation of Air Pollutant Emission Factors, AP-42, 5^th Edition, United States Environmental Protection Agency, January 1995.

3.3       Urban/Rural Classification

            Emission sources may be located in a variety of settings. For modelling purposes these are classed as either rural or urban so as to reflect the enhanced mixing that occurs over urban areas due to the presence of buildings and urban heat effects. The selection of either rural or urban dispersion coefficients in a specific application should follow a land use classification procedure. If the land use types including industrial, commercial and residential uses account for 50% or more of an area within 3 km radius from the source, the site is classified as urban; otherwise, it is classed as rural.

3.4       Surface Roughness Height

            This parameter is closely related to the land use characteristics of a study area and associated with the roughness element height. As a first approximation, the surface roughness can be estimated as 3 to 10 percent of the average height of physical structures. Typical values used for urban and new development areas are 370 cm and 100 cm, respectively.

3.5       Receptors

            These include discrete receptors representing all the identified air sensitive receivers at their appropriate locations and elevations and any other discrete or grid receptors for supplementary information. A receptor grid, whether Cartesian or Polar, may be used to generate results for contour outputs.

3.6       Particle Size Classes

            In evaluating the impacts of dust-emitting activities, suitable dust size categories relevant to the dust sources concerned with reasonable breakdown in TSP (< 30 μm) and RSP (< 10 μm) compositions should be used.

3.7       NO₂ to NO_x Ratio

            The conversion of NO_x to NO₂ is a result of a series of complex photochemical reactions and has implications on the prediction of near field impacts of traffic emissions. Until further data are available, three approaches are currently acceptable in the determination of NO₂:

(a) Ambient Ratio Method (ARM) - assuming 20% of NO_x to be NO₂; or

(b) Discrete Parcel Method (DPM, available in the CALINE4 model); or

(c) Ozone Limiting Method (OLM) - assuming the tailpipe NO₂ emission to be 7.5% of NO_x and the background ozone concentration to be in the range of 57 to 68 μg/m³ depending on the land use type (see also the EPD reference paper 'Guidelines on Assessing the 'TOTAL' Air Quality Impacts' in Appendix B-2).

3.8       Odour Impact

            In assessing odour impacts, a much shorter time-averaging period of 5 seconds is required due to the shorter exposure period tolerable by human receptors. Conversion of model computed hourly average results to 5-second values is therefore necessary to enable comparison against recommended standard. The hourly concentration is first converted to 3-minute average value according to a power law relationship which is stability dependent (Ref. 3) and a result of the statistical nature of atmospheric turbulence. Another conversion factor (10 for unstable conditions and 5 for neutral to stable conditions) is then applied to convert the 3-minute average to 5-second average (Ref. 4). In summary, to convert the hourly results to 5-second averages, the following factors can be applied:

Stability Category 1-hour to 5-sec Conversion Factor

A & B                                                      45

C                                                              27

D                                                              9

E & F                                                       8

Under ‘D’ class stability, the 5-second concentration is approximately 10 times the hourly average result. Note, however, that the combined use of such conversion factors together with the ISCST results may not be suitable for assessing the extreme close-up impacts of odour sources.

Ref.(3): Richard A. Duffee, Martha A. O’Brien and Ned Ostojic, ‘Odor Modeling – Why and How’, Recent Developments and Current Practices in Odor Regulations, Controls and Technology, Air & Waste Management Association, 1991.

Ref.(4): A.W.C. Keddie, ‘Dispersion of Odours’, Odour Control – A Concise Guide, Warren Spring Laboratory, 1980.

3.9       Plume Rise Options

            The ISCST3 model provides by default a list of the U.S. regulatory options for concentration calculations. These are all applicable to the Hong Kong situations except for the 'Final Plume Rise' option. As the distance between sources and receptors are generally fairly close, the non-regulatory option of  'Gradual Plume Rise' should be used instead to give more accurate estimate of near-field impacts due to plume emission. However, the 'Final Plume Rise' option may still be used for assessing the impacts of distant sources.

3.10     Portal Emissions

            These include traffic emissions from tunnel portals and any other similar openings and are generally modelled as volume sources according to the PIARC 91 (or more up-to-date version) recommendations (Ref. 5, section III.2). For emissions arising from underpasses or any horizontal openings of the like, these are treated as area or point sources depending on the source physical dimensions. In all these situations, the ISCST3 model or more sophisticated models will have to be used instead of the CALINE4 model. In the case of portal emissions with significant horizontal exit velocity which cannot be handled by the ISCST3 model, the impacts may be estimated by the TOP model (Ref. 6) or any other suitable models subject to prior agreement with EPD.  The EPD’s 'Guidelines on the Use of Alternative Computer Models in Air Quality Assessment' should also be referred to in Appendix B-3.

Ref.(5): XIXth World Road Congress Report, Permanent International Association of Road Congresses (PIARC), 1991.

Ref.(6): N. Ukegunchi, H. Okamoto and Y. Ide "Prediction of vehicular emission pollution around a tunnel mouth", Proceedings 4th International Clean Air Congress, pp. 205-207, Tokyo, 1977.

3.11     Background Concentrations

            Background concentrations are required to account for far-field sources which cannot be estimated by the model. These values, to be used in conjunction with model results for assessing the total impacts, should be based on long term average of monitoring data at location representative of the study site. Please make reference to the paper 'Guidelines on Assessing the 'TOTAL' Air Quality Impacts' in Appendix B-2 for further information.

3.11     Output

            The highest short-term and long-term averages of pollutant concentrations at prescribed receptor locations are output by the model and to be compared against the relevant air quality standards specified for the relevant pollutant. Contours of pollutant concentration are also required for indicating the general impacts of emissions over a study area.

            Copies of model files in electronic format should also be provided for EPD's reference.

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Schedule 1

Air Quality Models Generally Accepted by

Hong Kong Environmental Protection Department for

Regulatory Applications as at 1 July 1998*

Industrial Source Complex Dispersion Model - Short Term Version 3 (ISCST3) or the latest version developed by U.S. Environmental Protection Agency

California Line Source Dispersion Model Version 4 (CALINE4) or the latest version developed by Department of Transportation, State of California, U.S.A.

Fugitive Dust Model (FDM) or the latest version developed by U.S. Environmental Protection Agency

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*          EPD is continually reviewing the latest development in air quality models and will update this Schedule accordingly.

Appendix B-2

Guidelines on Assessing the 'TOTAL' Air Quality Impacts

[The information contained in this Appendix is only meant to assist the Applicant in performing the air quality assessment.  The Applicant must exercise professional judgment in applying this general information for the Project.]

1.         Total Impacts - 3 Major Contributions

1.1 In evaluating the air quality impacts of a proposed project upon air sensitive receivers, contributions from three classes of emission sources depending on their distance from the site should be considered. These are:

Primary contributions:               project induced

Secondary contributions:           pollutant-emitting activities in the immediate neighbourhood

Other contributions:                  pollution not accounted for by the previous two

(Background contributions)

2.         Nature of Emissions

2.1       Primary contributions

            In most cases, the project-induced emissions are fairly well defined and quite often (but not necessarily) the major contributor to local air quality impacts. Examples include those due to traffic network, building or road construction projects.

2.2       Secondary contributions

            Within the immediate neighbourhood of the project site, there are usually pollutant emitting activities contributing further to local air quality impacts. For most local scale projects, any emission sources in an area within 500m radius of the project site with notable impacts should be identified and included in an air quality assessment to cover the short-range contributions. In the exceptional cases where there is one or more significant sources nearby, the study area may have to be extended or alternative estimation approach employed to ensure these impacts are reasonably accounted for.

2.3       Background contributions

            The above two types of emission contributions should account for, to a great extent, the air quality impacts upon local air sensitive receivers, which are often amenable to estimation by the 'Gaussian Dispersion' type of models. However, a background air quality level should be prescribed to indicate the baseline air quality in the region of the project site, which would account for any pollution not covered by the two preceding contributions. The emission sources contributing to the background air quality would be located further afield and not easy to identify. In addition, the transport mechanism by which pollutants are carried over long distances (ranging from 1km up to tens or hundreds of kms) is rather complex and cannot be adequately estimated by the 'Gaussian' type of models.

3.         Background Air Quality - Estimation Approach

3.1       The approach

           In view of the difficulties in estimating background air quality using the air quality models currently available, an alternative approach based on monitored data is suggested. The essence of this approach is to adopt the long-term (5-year) averages of the most recent monitored air quality data obtained by EPD. These background data would be reviewed yearly or biennially depending on the availability of the monitored data. The approach is a first attempt to provide a reasonable estimate of the background air quality level for use in conjunction with EIA air quality assessment to address the cumulative impacts upon a locality. This approach may be replaced or supplemented by superior modelling efforts such as that entailed in PATH (Pollutants in the Atmosphere and their Transport over Hong Kong), a comprehensive territory-wide air quality modelling system currently being developed for Hong Kong. Notwithstanding this, the present approach is based on measured data and their long term regional averages; the background values so derived should therefore be indicative of the present background air quality. In the absence of any other meaningful way to estimate a background air quality for the future, this present background estimate should also be applied to future projects as a first attempt at a comprehensive estimate until a better approach is formulated.

3.2       Categorisation

            The monitored air quality data, by 'district-averaging' are further divided into three categories, viz, Urban, Industrial and Rural/New Development. The background pollutant concentrations to be adopted for a project site would depend on the geographical constituency to which the site belongs. The categorisation of these constituencies is given in Section 3.4. The monitoring stations suggested for the 'district-averaging'(arithmetic means) to derive averages for the three background air quality categories are listed as follows:

Urban:                                   Kwun Tong, Sham Shui Po, Tsim Sha Tsui and Central/Western

Industrial:                               Kwun Tong, Tsuen Wan and Kwai Chung

Rural/New Development:       Sha Tin, Tai Po, Junk Bay, Hong Kong South and Yuen Long

            The averaging would make use of data from the above stations wherever available. The majority of the monitoring stations are located some 20m above ground.

3.3       Background pollutant values

            Based on the above approach, background values for the 3 categories have been obtained for a few major air pollutants as follows:

POLLUTANT	URBAN	INDUSTRIAL	RURAL / NEW DEVELOPMENT
NO2	59	57	39
SO2	21	26	13
O3	62	68	57
TSP	98	96	87
RSP	60	58	51

            All units are in micrograms per cubic metre. The above values are derived from 1992 to 1996 annual averages with the exception of ozone which represent annual average of daily hourly maximum values for year 1996.

            In cases where suitable air quality monitoring data representative of the study site such as those obtained from a nearby monitoring station or on-site sampling are not available for the prescription of background air pollution levels, the above tabulated values can be adopted instead.  Strictly speaking, the suggested values are only appropriate for long term assessment. However, as an interim measure and until a better approach is formulated, the same values can also be used for short term assessment. This implies that the short term background values will be somewhat under-estimated, which compensates for the fact that some of the monitoring data are inherently influenced by secondary sources because of the monitoring station location.

            Indeed, if good quality on-site sampling data which cover at least one year period are available, these can be used to derive both the long term (annual) and short term (daily / hourly) background values, the latter are usually applied on an hour to hour, day to day basis.

3.4       Site categories

            The categories to which the 19 geographical constituencies belong are listed as follows:

DISTRICT	AIR QUALITY CATEGORY
Islands	Rural / New Development
Southern	Rural / New Development
Eastern	Urban
Wan Chai	Urban
Central & Western	Urban
Sai Kung	Rural / New Development
Kwun Tong	Industrial
Wong Tai Sin	Urban
Kowloon City	Urban
Yau Tsim	Urban
Mong Kok	Urban
Sham Shui Po	Urban
Kwai Tsing	Industrial
Sha Tin	Rural / New Development
Tsuen Wan	Industrial
Tuen Mun	Rural / New Development
Tai Po	Rural / New Development
Yuen Long	Rural / New Development
Northern	Rural / New Development

3.5       Provisions for 'double-counting’

            The current approach is, by no means, a rigorous treatment of background air quality but aims to provide an as-realistic-as-possible approximation based on limited field data. 'Double-counting' of 'secondary contributions' may be apparent through the use of such 'monitoring-based' background data as some of the monitoring stations are of close proximity to existing emission sources. 'Primary contributions' due to a proposed project (which is yet to be realized) will not be double-counted by such an approach. In order to avoid over-estimation of background pollutant concentrations, an adjustment to the values given in Section 3.3 is possible and optional by multiplying the following factor:

                 (1.0 - E_{Secondary contributions}/E_Territory)

                where E stands for emission.

            The significance of this factor is to eliminate the fractional contribution to background pollutant level of emissions due to 'secondary contributions' out of those from the entire territory. In most cases, this fractional contribution to background pollutant levels by the secondary contributions is minimal.

4.         Conclusions

4.1       The above described approach to estimating the total air quality impacts of a proposed project, in particular the background pollutant concentrations for air quality assessment, should be adopted with immediate effect. Use of short term monitoring data to prescribe the background concentrations is no longer acceptable.

Appendix B-3

Guidelines on the Use of Alternative Computer Models

in Air Quality Assessment

[The information contained in this Appendix is only meant to assist the Applicant in performing the air quality assessment.  The Applicant must exercise professional judgment in applying this general information for the Project.]

1.            Background

1.1 In Hong Kong, a number of Gaussian plume models are commonly employed in regulatory applications such as application for specified process licences and environmental impact assessments (EIAs). These frequently used models (as listed in Schedule 1 attached; hereafter referred to as Schedule 1 models) have no regulatory status but form the basic set of tools for local-scale air quality assessment in Hong Kong.

1.2 However, no single model is sufficient to cover all situations encountered in regulatory applications. In order to ensure that the best model available is used for each regulatory application and that a model is not arbitrarily applied, the project proponent (and/or its environmental consultants) should assess the capabilities of various models available and adopt one that is most suitable for the project concerned.

1.3 Examples of situations where the use of an alternative model is warranted include:

(i) the complexity of the situation to be modelled far exceeds the capability of the Schedule 1 models; and

(ii)           the performance of an alternative model is comparable or better than the Schedule 1 models.

1.4          This paper outlines the demonstration / submission required in order to support the use of an alternative air quality model for regulatory applications for Hong Kong.

2.            Required Demonstration / Submission

2.1          Any model that is proposed for air quality applications and not listed amongst the Schedule 1 models will be considered by EPD on a case-by-case basis.  In such cases, the proponent will have to provide the followings for EPD's review:

(i) Technical details of the proposed model; and

(ii) Performance evaluation of the proposed model

               Based on the above information, EPD will determine the acceptability of the proposed model for a specific or general applications. The onus of providing adequate supporting materials rests entirely with the proponent.

2.2          To provide technical details of the proposed model, the proponent should submit documents containing at least the following information:

(i) mathematical formulation and data requirements of the model;

(ii) any previous performance evaluation of the model; and

(iii) a complete set of model input and output file(s) in commonly used electronic format.

2.3 On performance evaluation, the required approach and extent of demonstration varies depending on whether a Schedule 1 model is already available and suitable in simulating the situation under consideration. In cases where no Schedule 1 model is found applicable, the proponent must demonstrate that the proposed model passes the screening test as set out in USEPA Document "Protocol for Determining the Best Performing Model" (Ref. 1).

Ref.(1): William M. Cox, ‘Protocol for Determining the Best Performing Model’; Publication No. EPA-454/R-92-025; U.S. Environmental Protection Agency, Research Triangle Park, NC.

2.4 For cases where a Schedule 1 model is applicable to the project under consideration but an alternative model is proposed for use instead, the proponent must demonstrate either that

(i) the highest and second highest concentrations predicted by the proposed model are within 2 percent of the estimates obtained from an applicable Schedule 1 model (with appropriate options chosen) for all receptors for the project under consideration; or

(ii) the proposed model has superior performance against an applicable Schedule 1 model based on the evaluation procedure set out in USEPA Document  "Protocol for Determining the Best Performing Model" (Ref. 1).

2.5 Should EPD find the information on technical details alone sufficient to indicate the acceptability of the proposed model, information on further performance evaluation as specified in Sections 2.3 and 2.4 above would not be necessary.

2.6 If the proposed model is an older version of one of the Schedule 1 models or was previously included in Schedule 1, the technical documents mentioned in Section 2.2 are normally not required.  However, a performance demonstration of equivalence as stated in Section 2.4 (i) would become necessary.

2.7 If EPD is already in possession of some of the documents that describe the technical details of the proposed model, submission of the same by the proponent is not necessary. The proponent may check with EPD to avoid sending in duplicate information.

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Schedule 1

Air Quality Models Generally Accepted by

Hong Kong Environmental Protection Department for

Regulatory Applications as at 1 July 1998*

Industrial Source Complex Dispersion Model - Short Term Version 3 (ISCST3) or the latest version developed by U.S. Environmental Protection Agency

California Line Source Dispersion Model Version 4 (CALINE4) or the latest version developed by Department of Transportation, State of California, U.S.A.

Fugitive Dust Model (FDM) or the latest version developed by U.S. Environmental Protection Agency

-------------------------------------------------------------------------------------------------------

*          EPD is continually reviewing the latest development in air quality models and will update this Schedule accordingly.

Appendix C

Water Quality Modeling Requirements

Modelling software general

1. The near field plume dispersion modelling software shall be capable of simulating the near field characteristics of the sewage plume discharged from a rosette type multiport outfall diffuser under various discharge flow rates and loads, current speeds and ambient water quality and stratification profiles.  The near field model shall have proven record of successful applications locally and overseas.

2. For simulating far field water quality conditions, the modelling software shall be fully 3-dimensional capable of accurately simulating the stratified condition, salinity transport, and effect of wind and tide within the model area.

3.         The far field modelling software shall consist of hydrodynamic, water quality and particle dispersion modules.  These modules shall have proven record of successful applications locally and overseas.

4.         The hydrodynamic and water quality modules shall be strictly mass conserved at all levels.

Model details – Calibration & Validation

1.         No field data collection is required for model calibration for this study.  However, the models shall be properly calibrated and validated before its use in this study, with the field data collected by:

· Hydraulic and Water Quality Studies in Victoria Harbour (1987)

· Port and Airport Development Strategy - Enhancement of WAHMO Mathematical Models (1990)

· Strategic Sewage Disposal Scheme Stage II - Oceanic Outfall, Oceanographic Surveys and Modelling(1992)

· Update on Cumulative Water Quality and Hydrological Effect of Coastal Developments and Upgrading of Assessment Tool (1998)

· Environmental and Engineering Feasibility Assessment Studies in relation to the Way Forward of the Harbour Area Treatment Scheme (2004)

· EPD’s routine monitoring data

· Tidal data from HK Observatory, Macau and relevant Mainland Authorities.

2.         Tidal data shall be calibrated and validated in both frequency and time domain manner.

3.         For the purpose of calibration and validation, the hydrodynamic model shall run for not less than 15 days of real sequence of tide (excluding model spin up) in both dry and wet seasons with due consideration of the time required for minimizing the effect of initial condition and convergence of results. 

4.         In general the hydrodynamic models shall be calibrated to the following criteria:

Criteria                                                        Level of fitness

with field data

· tidal elevation (rms)                                                             < 8 %

· maxi. phase error at HW and LW                                       < 20 minutes

· maxi. current speed deviation                                              < 30 %

· maximum phase error at peak speed                                   < 20 minutes

· maximum direction error at peak speed                               < 15 degrees

· maximum salinity deviation                                                  < 2.5 ppt

Model details – Simulation

1.         The near field model shall be used to simulate the characteristics of the sewage plume in the vicinity of the submarine outfall to determine the initial dilution, plume dimensions, rise height, merging and trapping in various flow conditions and the optimal diffuser configuration.  These results shall be used, where appropriate, as inputs to the far field models.  Subject to the findings of the near field plume dispersion modelling, the far field impact of any significant level of pollutants, including residual chlorine, chlorination by-products and excess sulphite, remaining outside the zone of initial dilution, shall be simulated and assessed to ascertain its impact on the receiving water system(s) and sensitive receivers.

2.         The water quality modelling results shall be qualitatively explainable, and any identifiable trend and variations in water quality shall be reproduced by the model.  The water quality model shall simulate and take account of the interaction of dissolved oxygen, phytoplankton, organic and inorganic nitrogen, phosphorus, silicate, BOD, temperature, suspended solids, air-water exchange, benthic processes, and contaminant release of dredged and disposed material.  It shall also simulate salinity and E. coli.  Salinity results simulated by hydrodynamic models and water quality models shall be demonstrated to be consistent.

3.         The hydrodynamic and water quality models shall be carefully designed such that its boundary is remote enough and would not be affected by the Project with a fine grid commensurate with the detail of assessment.  In general, the model grid size shall be less than 400m in open waters and less than 75m around sensitive receivers and outfall diffusers.  The grid schematization shall be agreed with EPD.  A fine grid model can be used for detailed assessment but shall either be dynamically linked to or form part of the far field model, which cover the Pearl Estuary and the Dangan (Lema) Channel to incorporate the effects of oceanic and Pearl River discharge processes, through nesting or gradual refinement techniques.

Modelling assessment

1. Scenarios to be assessed shall cover all phases of development being considered, including construction and operation of the Project, and temporary discharges via the emergency outfalls.  They shall cover the baseline condition and scenarios with various different options proposed by the Applicant in order to quantify the environmental impacts and improvements that will be brought about by these options.  Corresponding pollution load, bathymetry and coastline shall be adopted in the model set up.

2.         Mixing zone analyses shall be performed using the near field model.  The model shall be run for different combinations of discharge flow rates and loads, current speeds and ambient water quality and stratification profiles to simulate the sewage plume discharging into the receiving water system(s).  The results shall be statistically analyzed to determine the spatial and temporal variations of pollutant concentrations in the plume and the extent and sizes of the mixing zones.  Critical conditions reflecting the lowest initial dilutions and highest pollutant concentrations shall be identified and assessed with emphasis on bacterial and toxicity contents, e.g. E.coli, total residual chlorine and chlorination by-products.

3.         The hydrodynamic models shall be run for (with proper model spin up) at least a real sequence of 15 days spring-neap tidal cycle in both dry season and wet season.

4.         For operation phase impact assessment, the water quality module shall run for a complete year incorporating monthly variations in Pearl River discharges, solar radiation, water temperature and wind velocity in the operational stage.  Construction phase impacts may be assessed by simulating typical spring-neap cycles in the dry and wet seasons.

5.         For assessment of temporary or emergency discharges if any, the Applicant shall estimate discharge loading, pattern and duration.  The worst case scenario of discharge near slack water of neap tide shall be assessed.  The simulation period shall cover at least 15 days spring-neap cycle in wet season, and shall be long enough for the receiving water to recover to its original state before such discharges.  Detailed methodology shall be agreed with EPD.

6.         The results shall be assessed for compliance with the relevant water quality objectives and criteria and the corresponding ecological and human health impacts. 

7.         For construction phase impact assessment, daily sedimentation / erosion rate shall be computed and its ecological impact shall be assessed. 

8.         The potential impact or improvement of water quality with respect to bacteria content, particularly at the bathing beaches, shall be modelled and assessed.

9.         Cumulative impacts due to other projects, activities or pollution sources within a boundary to the agreement of EPD shall also be predicted and quantified. 

10.       All modelling input data and results shall be submitted in digital media to EPD.

- END -

Appendix D

Guidelines for Marine Archaeological Investigation (MAI)

The standard practice for MAI should consist of four separate tasks, i.e. (1) Baseline Review, (2) Geophysical Survey, (3) Establishing Archaeological Potential and (4) Remote Operated Vehicle (ROV)/Visual Diver Survey/Watching Brief.

(1)      Baseline Review

1.1     A baseline review should be conducted to collate the existing information in order to identify the potential for archaeological resources and, if identified, their  likely character, extent, quality and value.

1.2 The baseline review will focus on known sources of archive data.  It will include :

a.         Geotechnical Engineering Office (GEO) – the Department holds extensive seabed survey data collected from previous geological research.

          b.        Marine Department, Hydrographic Office – the Department holds a substantial archive of hydrographic data and charts.

    c.        The Royal Naval Hydrographic Department in the UK – the Department maintains an archive of all survey data collected by naval hydrographers.

1.3      The above data sources will provide historical records and more details geological analysis of submarine feature which may have been subsequently masked by more recent sediment deposits and accumulated debris.

(2)      Geophysical Survey

2.1      Extensive geophysical survey of the study area should deployed high resolution boomer, side scan sonar and an echo sounder.   The data received from the survey would be analysed in detail to provide :

    a.        Exact definition of the areas of greatest archaeological potential.

b.                    Assessment of the depth and nature of the seabed sediments to define which areas consist of suitable material to bury and preserve archaeological material.

          c.                    Detailed examination of the boomer and side scan sonar records to map anomalies on the seabed which may be archaeological material.

(3)      Establishing Archaeological Potential

3.1      The data examined during Task 1 and 2 will be analysed to provide an indication of the likely character and extent of archaeological resources within the study area.  This would facilitate formulation of a strategy for investigation.

3.2      The results would be presented as a written report and charts. If there is no indication of archaeological material there would be no need for further work.

(4)      Remote Operated Vehicle (ROV)/Visual Diver Survey/Watching Brief

4.1        Subject to the outcome of Task 1, 2 and 3, accepted marine archaeological practice would be to plan a field evaluation programme to acquire more detailed data on areas identified as having archaeological potential.  The areas of archaeological interest can be inspected by ROV or divers.  ROV or a team of divers with both still and video cameras would be used to record all seabed features of archaeological interest.

4.2        Owing to the heavy marine traffic in Hong Kong, the ROV/visual diver survey may not be feasible to achieve the target.  If that is the case, an archaeological watching brief is the most appropriate way to monitor the dredging operations in areas of identified high potential to obtain physical archaeological information.

4.3        A sampling strategy for an archaeological watching brief would be prepared based on the results of Task 1, 2 and 3 to focus work on the areas of greatest archaeological potential.  Careful monitoring of the dredging operations would enable immediate identification and salvage of archaeological material.  If archaeological material is found, the AMO should be contacted immediately to seek guidance on its significance and appropriate mitigation measures would be prepared.

4.4          If Task 4 is undertaken, the results would be presented in a written report with charts.

Appendix E

Implementation Schedule

EIA Ref.

EM&A Ref.

Recommended Mitigation Measures

Objectives of the Recommended Measure & Main Concerns to address

Who to implement the measure ?

Location of the measure

When to implement the measure ?

What requirements or standards for the measure to achieve ?