Environmental Impact Assessment Ordinance (Cap. 499)
Section 5 (7)
Environmental Impact Assessment Study Brief No. ESB-078/2001
Project Title: Lamma Power Station Navigation Channel Improvement
Name of Applicant: The Hongkong Electric Company Limited
(hereinafter known as the "Applicant")


1.1 An application (No. ESB-078/2001) 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 11 June 2001 with a Project Profile (No. PP-134/2001).

1.2 The Project Profile (No. PP-134/2001) proposes to improve the existing navigation channel at the west of the Lamma Power Station (Location Plan in Figure 1).

1.3 The construction works include dredging of marine sediment at an existing navigation channel and disposal of dredged sediment. The estimated dredging volume is 2.98 million cubic meters (measured in-situ). The dredged sediment will be transported by marine vessels and is expected to be disposed at Government approved mud disposal sites.

1.4 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.

1.5 The purpose of this EIA study is to provide information on the nature and extent of environmental impacts arising from the proposed project and other projects 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 proposed project;

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

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


2.1 The objectives of the EIA study are as follows:

(i) to describe the proposed project and associated works together with the requirements for carrying out the proposed project;

(ii) to consider alternative method(s) of the dredging work and design to ensure safe delivery of fuel to the Power Station; and to compare the environmental benefits and dis-benefits of each of the method(s) and design in selecting a preferred one;

(iii) to identify and describe elements of community and environment likely to be affected by the proposed project and/or likely to cause adverse impacts to the proposed project, including natural and man-made environment;

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

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

(v) 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 proposed project in relation to the sensitive receivers and potential affected uses;

(vi) to identify, assess and specify methods, measures and standards, to be included in the detailed design, construction and operation of the proposed project which are necessary to mitigate these environmental impacts and reducing them to acceptable levels;

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

(viii) to identify, within the study area, any individual project(s) that fall under Schedule 2 of the EIA Ordinance; to ascertain whether the findings of this EIA study have adequately addressed the environmental impacts of those projects; and, where necessary, to identify the outstanding issues that need to be addressed in any further detailed EIA study; and

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


3.1 The Purpose

The purpose of this EIA study brief is to scope the key issues of the EIA study. The Applicant has to demonstrate in the EIA report that the criteria in the relevant sections of the Technical Memorandum on the 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 project mentioned in Sections 1.2 and 1.3 above, within the location as shown in the attached Figure 1. The EIA study shall address the likely key issues described below; together with any other key issues identified during the course of the EIA study:

i) the potential water quality impacts arising from the construction works during the construction and operation phases of the proposed project.

ii) the potential noise impacts arising from the construction works of the proposed project.

iii) the potential ecological impacts arising from the construction and operation of the proposed project.

iv) the potential impacts on the fisheries arising from the construction and operation of the proposed project.

v) the cumulative environmental impacts of the above arising from the construction works of the proposed project together with other construction activities taken place concurrently.

3.3 Consideration of Alternatives

Consideration of Different Construction Methods

The Applicant shall consider alternative methods and schedules for the proposed dredging works. The Applicant shall also compare the environmental impacts, environmental benefits and dis-benefits of each of the possible options, and provide reasons for selecting the final preferred option including the environmental factors considered in the 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 Noise Impact The Applicant shall follow the criteria and guidelines for evaluating and assessing noise impact as stated in Annexes 5 and 13 of the TM, respectively. The noise impact assessment shall include the following :

(i) 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.

(ii) 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.

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

The Applicant shall provide an inventory of noise sources for all the plants and equipment relating to the proposed dredging works. Confirmation of the validity of the inventory shall be obtained from the relevant government departments/authorities.

(iv) Construction Noise Assessment

(a) The Applicant shall carry out assessment of noise impact from construction 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 paragraph 5.3. of Annex 13 of the TM. The criteria in Table 1B of Annex 5 of the TM shall be adopted in the assessment.

(b) If the unmitigated construction noise levels are found exceeding the relevant criteria, the Applicant shall propose practicable direct mitigation measures (including quieter alternative methods, re-scheduling and restricting hours of operation of noisy task) to minimize the impact. If the mitigated noise levels still exceed the relevant criteria, the duration of the noise exceedance shall be given.

3.4.2 Water Quality Impact The Applicant shall follow the criteria and guidelines for evaluation and assessing water pollution as stated in Annexes 6 and 14 of the TM. The assessment area for this water quality assessment shall cover the Southern and Western Buffer Water Control Zone as designated under the Water Pollution Control Ordinance. This study area could be extended to include other areas during the course of the EIA study if found justifiable. The Applicant shall identify and analyze all physical, chemical and biological disruptions of marine water system arising from the construction and operation of the proposed project. The Applicant shall include in the water quality impact assessment the following major tasks:

(i) collect and review relevant background information on the existing and planned water system.

(ii) characterize water and sediment quality based on existing information or information collected from appropriated site surveys/tests.

(iii) identify and analyze existing, planned/committed activities and beneficial uses related to the water system and identify all water sensitive receivers. The Applicant shall refer to those developments and uses earmarked on the relevant Outline Zoning Plans, Outline Development Plans and Layout Plans.

(iv) identify pertinent water and sediment quality objectives, criteria and standards for the water system and sensitive receivers identified in (iii) above.

(v) identify any alteration(s)/change(s) to bathymetry or flow regimes.

(vi) identify, analyze and quantify all existing, future and other project(s) related water and sediment pollution sources (which shall include maintenance dredging of marine sediment for the navigation channel as necessary); and analyze these in relation to the provision and adequacy of future facilities to reduce such pollution in terms of capacity and levels of treatment.

(vii) provide an emission inventory on the quantities and characteristics of all the pollution sources identified in (vi) above and to conduct appropriate field investigation and laboratory tests to fill in any major information gaps as appropriate.

(viii) evaluate and quantify the possible impacts arising from the dredging works. The Applicant shall identify clearly the nature, extent and rate of the dredging works. Appropriate laboratory tests such as elutriate tests (USACE) and sediment pore water (interstitial water) analyses should be performed on the sediment samples to simulate and quantify the degree of mobilization of various contaminants such as metals, ammonia, trace organic contaminants such as PCBs, PAHs, TBT and chlorinated pesticides into the water column during dredging.

(ix) predict and quantify impacts on the affected water system(s) and the sensitive receivers due to those alterations and changes identified in (v) above and the pollution sources identified in (vi) above. The Applicant shall conduct full scale mathematical modelling, simulating situation during various construction phases and different operation stages of the navigation channel (which shall include mainatenance dredging of marine sediment for the navigation channel as necessary), assessing both the local and global effects on flow regime, erosion, re-suspension and sediment dispersion and water quality due to the interim and ultimate alteration of shoreline and bathymetry as a result of dredging marine sediment. The modelling assessment should take into account the additional pollution loading and oxygen demand exerted by sediment disturbed and any fill materials. The mathematical modelling requirements are set out in Annex A.

Cumulative impacts due to other dredging, filling or dumping activities within a boundary around the assessment area, such as the dredging and filling works for the new power station at Lamma Extension, the Yung Shue Wan Reclamation Phase 2 works, etc., to be agreed by the Director, shall be predicted and quantified.

Suitable mud dredging and disposal methods shall be recommended to reduce any adverse effects found.

(x) propose water pollution prevention and mitigation measures to be implemented during the construction and operational stages so as to reduce the water and sediment quality impacts to within standards.

(xi) evaluate and quantify any residual impacts on the affected water system(s) and sensitive receivers with regard to the appropriate water and sediment quality objectives, criteria, standards or guidelines.

(xii) Dredging and Dumping

(a) identification and quantification of all dredging, transportation and disposal activities and requirements. Potential dumping ground to be involved shall also be identified. Field investigation, sampling and chemical and biological laboratory tests to characterize the sediment/mud concerned shall be conducted as appropriate. The ranges of parameters to be analyzed; the number, type and methods of sampling; sample preservation; chemical and biological laboratory test method; and the laboratory to be used shall be subject to the approval of the Director. Any seriously contaminated sediment which requires special treatment and/or disposal arrangement in accordance with WBTC No.3/2000 shall be identified by both chemical and biological tests. If the presence of such sediment is confirmed, the Applicant shall identify the most appropriate treatment and/or disposal arrangement and demonstrate its feasibility.

(b) identification and evaluation of the best practicable dredging methods to minimize dredging and dumping requirements and demand for fill sources based on the criterion that existing marine mud shall be left in place and not to be disturbed as far as possible.

3.4.3 Waste Management Implications 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. 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 arising as a result of the construction activities, based on the sequence and duration of these activities.

(ii) Proposal for Waste Management

(a) Prior to considering the disposal option, opportunities for reducing waste generation and on-site or off-site reuse shall be fully evaluated.

(b) Having taken into account all the opportunities for reducing waste generation and maximizing reuse, the quantity of the waste required to be disposed of as a consequence shall be estimated and the disposal options for the wastes described in detail. The disposal method recommended for the wastes shall take into account the result of the assessment set out in (c) below.

(c) The impact caused by handling, collection, and disposal of wastes shall be addressed in detail and appropriate mitigation measures proposed to mitigate the induced environmental impacts.

3.4.4 Marine Ecological Impact The Applicant shall examine the flora, fauna and other components of the ecological habitats within the assessment area. The assessment area shall be the same as for the water quality assessment, or the area likely to be impacted by the project. The Applicant shall carry out the following tasks in the assessment :

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

(ii) evaluation of the information collected and identification of any information gap relating to the assessment of potential ecological impacts to the aquatic environment;

(iii) carry out any necessary field surveys which shall cover the wet and dry seasons (the duration shall be at least 6 months) and investigations to verify the information collected, fill the information gaps identified and fulfill the objectives of the EIA study;

(iv) establishment of the general ecological profile and description of 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 study area;

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

(d) representative colour photos of any important ecological features identified, and

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

(v) investigation and description of the existing wildlife uses of various habitats with special attention to those with conservation interests, including;

(a) corals;

(b) Finless Porpoise (Neophocaena phocaenoides) and Chinese White Dolphin (Sousa chinensis);

(c) any other notable benthic or littoral communities;

(d) any other habitats and wildlife groups identified as having special conservation interests by the study;

(vi) describe all recognized sites of conservation importance in the assessment area including potential Marine Parks and assess whether these sites will be affected by the proposed project or not;

(vii) identify and quantify as far as possible, using suitable methodology and considering also any works activities from other projects reasonably likely to occur at the same time, any direct, indirect, on-site, off-site, primary, secondary and cumulative ecological impacts from the proposed project such as destruction or disturbance 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) potential disturbance to marine mammals during dredging;

(b) removal or disruption of potentially valuable benthic communities; and

(c) deterioration or disturbance to corals or other marine habitats of conservation value, including any discovered during the course of the assessment

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

(ix) recommendation of all possible alternatives (such as modifications of design and other construction methods) and practicable mitigation measures to avoid, minimize and/or compensate for the adverse ecological impacts identified;

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

(xi) determination and quantification as far as possible the residual ecological impacts after implementation of the proposed mitigation measures;

(xii) evaluation of 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

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

3.4.5 Fisheries Impact The Applicant shall follow the criteria and guidelines for evaluating and assessing fisheries impact as stated in Annexes 9 and 17 of the TM. The assessment shall cover any potential impact of the proposed project on capture fisheries, during the construction and operation phase. The fisheries impact assessment shall include the following tasks:

(i) description of the physical environmental background;

(ii) description and quantification as far as possible existing capture fisheries activities;

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

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

(v) identification and quantification any direct/indirect and on-site/off-site impacts of fisheries;

(vi) evaluation of the impacts and make proposals 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 the need for monitoring and, if necessary, propose a monitoring and audit programme.

3.4.6 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.


4.1 The Applicant shall identify and justify in the EIA study whether there is any need for EM&A activities, during the dredging operations of the proposed project, and if affirmative, to define the scope of the EM&A requirements for the Project in the EIA study.

4.2 Subject to the confirmation of the EIA study findings, the Applicant shall comply with the requirements as stipulated in Annex 21 of the TM. The Applicant shall propose and justify the need for real-time reporting of monitoring data for the Project through a dedicated internet website accessible to the public.

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


5.1 This EIA study brief is valid for 24 months after the date of issue. If the EIA study does not commence within this period, the Applicant shall apply to the Director for another EIA study brief afresh before commencement of the EIA study.


6.1 In preparing the EIA report, the Applicant shall make reference to the general guidance as set out in Annex 11 and Annex 20 of the TM. Annex 11 lists out the main sections of the content of an EIA report and Annex 20 sets out the guidelines used by the Director for review of the EIA report.

6.2 The Applicant shall provide the Director with :

(i) as perusal to section 6(2) of the EIAO,
- 40 copies of the EIA report in English; and
- 40 copies of the Executive Summary(ies) (in English and Chinese), to be supplied at the time of application for approval of the EIA report;

(ii) as perusal to section 7(1) of the EIAO,
- when necessary, addendum to the EIA report and the Executive Summary(ies) submitted in (i) above
to be supplied upon the advice by the Director for public exhibition;

(iii) as perusal to section 7(5) of the EIAO,
- 20 copies of the EIA report in English; and
- 50 copies of the Executive Summary(ies) (in English and Chinese), to be supplied upon advice by the Director for consultation with the Advisory Council on the Environment.

6.3 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.

6.4 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.

6.5 Electronic copies of the EIA report and the Executive Summary(ies) shall be submitted to the Director at the time of application for approval of the EIA Report.

6.6 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.

6.7 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.


7.1 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.

7.2 If there is any key change in the scope of the proposed project mentioned in sections 1.2 and 1.3 of this EIA study brief and in Project Profile No. PP-134/2001, 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 proposed project fundamentally alter the key scope of the EIA study brief, the Applicant shall apply to the Director for another EIA study brief afresh.


July 2001
Environmental Protection Department

Annex A

Modelling requirements
Environmental Impact Assessment Study
Lamma Power Station Navigation Channel Improvement

Modelling software general

1. 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.

2. The modelling software shall consist of hydrodynamic, water quality and particle dispersion modules. The hydrodynamic and water quality modules shall have been proven with successful applications locally and overseas.

3. 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 in the area including the Western Harbour, East and West Lamma Channels, and south of the Lamma Island, with the field data collected by:

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

3. For the purpose of calibration and validation, the 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 to establish initial conditions.

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 suspended solids model for assessing impacts of sediment loss due to marine works shall incorporate the processes of settling, deposition and erosion. Contaminant release and DO depletion during dredging and dumping shall be simulated by the model.

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 be able to simulate and take account of the interaction of dissolved oxygen, phytoplankton, organic and inorganic nitrogen, phosphorus, silicate, BOD, temperature, suspended solids, air-water exchange, contaminant release of dredged and disposed material, and benthic processes. It shall also be able to simulate salinity and E. coli. Salinity results simulated by hydrodynamic models and water quality models shall be demonstrated to be consistent.

3. The models shall at least cover the Hong Kong waters, the Pearl Estuary and the Lema Channel to incorporate all major influences on hydrodynamic and water quality. A fine grid model can be used for detailed assessment of this study. It shall cover at least the Ma Wan, western Victoria Harbour, West and East Lamma Channels, and south of Lamma Island and Hong Kong Island.

4. In general, grid size at the area affected by the project shall be less than 400 m in open waters and less than 75 m around sensitive receivers. The grid schematisation shall be agreed with the Director. All models shall either be dynamically linked to a far field model or form part of a larger model by gradual grid refinement.

Modelling assessment

1. Scenarios to be assessed shall cover all phases of development being considered. Corresponding pollution load, bathymetry and coastline shall be adopted in the model set up.

2. Hydrodynamic and water quality 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.

3. The results shall be assessed for compliance of Water Quality Objectives. Any changes in hydrodynamic regime shall be assessed. Daily sedimentation rate shall be computed and its ecological impact shall be assessed.

4. Assess the impact on all sensitive receivers including the application of particle dispersion module, where appropriate.

5. All modelling input data and results shall be submitted in digital media to the Director.

- End of Annex A -


Annex B | Figure 1