Report Ref: R8109/06 Issue 6

Date: September November 2005

 

 

 

 

 

 

 

 

 

 

 

Agreement No. CE 18/2002 (EP)

Environmental Impact Assessment Study for

Construction of Helipads at

Peng Chau and Lamma Island - Investigation

 

 

EIA Study for Helipad at
Yung Shue Wan, Lamma Island

 

Final EIA Study Report

 

 

 

 

           

 

 

 

 

 

 

 

 

                                                                                                                 

 

 

 

BMT Asia Pacific Limited in Association With:

 

Hyder Consulting Limited

Asiatic Marine Limited

Archaeo-Environments Limited

Cosine Limited


 

DOCUMENT CONTROL SHEET

 

 

Client:

Civil Engineering and Development Department

 

 

 

Title:

 

EIA Study for Helipad at Yung Shue Wan, Lamma Island
Final EIA Study Report

 

 

 

Job No:

8109

Ref:

R/8109/06 Issue 6

Version:

Final

Date:

September November 2005

 

 

Prepared under the Management of:

 

Signature:

 

 

 

 

 

Name

Antony Wong

Position

Environmental Consultant

 

 

Reviewed and Approved by:

 

Signature:

 

 

 

 

 

Name

Ben Ridley

Position

Director

 

 

Filename

Final(YSW)-EIA_Issue 6 (Master).doc

 

 

Distribution:  Original to Project Quality Records File

Page:  1   of    1

 


CONTENTS

1        Introduction                                                                                                            1-1

1.1     General                                                                                                                1-1

1.2     Project Background                                                                                               1-1

1.3     Purpose and Approach of the EIA Study                                                                 1-2

1.4     Structure of this EIA Study Report                                                                          1-3

2        Project Description                                                                                               2-12-12-12-12-3

2.1     Key Project Requirements                                                                                     2-12-12-12-12-3

2.2     Project History and Site Selection                                                                          2-22-22-22-22-4

2.3     Project Characteristics and Site Location                                                              2-10

2.4     Nearby Projects                                                                                                  2-11

2.5     Likely Future Environmental Conditions Without the Project                                    2-12

3        Air Quality Impact Assessment                                                                           3-1

3.1     Introduction                                                                                                          3-1

3.2     Relevant Guidelines, Standards & Legislation                                                          3-1

3.3     Baseline Conditions and Air Sensitive Receivers                                                      3-2

3.4     Construction Dust Impact Assessment                                                                   3-4

3.5     Mitigation Measures                                                                                              3-5

3.6     Environmental Monitoring and Audit Requirements                                                   3-5

3.7     Conclusions and Recommendations                                                                       3-5

4        Noise Impact Assessment                                                                                      4-1

4.1     Introduction                                                                                                          4-1

4.2     Relevant Guidelines, Standards & Legislation                                                          4-1

4.3     Noise Sensitive Receivers                                                                                      4-4

4.4     Noise Environment at Yung Shue Wan                                                                    4-6

4.5     Construction Noise Impact Assessment                                                                  4-6

4.6     Operational Noise Impact Assessment                                                                   4-9

4.7     Environmental Monitoring and Audit Requirements                                                 4-194-194-194-194-20

4.8     Conclusions and Recommendations                                                                     4-204-204-204-204-23

4.9     References                                                                                                         4-214-214-214-214-24

5        Waste Management Assessment                                                                          5-1

5.1     Introduction                                                                                                          5-1

5.2     Legislation & Standards                                                                                         5-1

5.3     Baseline Conditions & Sensitive Receivers                                                              5-2

5.4     Assessment Methodology                                                                                     5-2

5.5     Waste Types                                                                                                        5-3

5.6     Impact Assessment and Evaluation                                                                        5-3

5.7     Summary of Waste Materials Generated                                                                 5-85-85-85-85-9

5.8     Impact Mitigation & Residual Impact Assessment                                                    5-95-95-95-95-10

5.9     Environmental Monitoring and Audit Requirements                                                 5-105-105-105-105-11

5.10   Conclusions and Recommendations                                                                     5-115-115-115-115-12

5.11   References                                                                                                         5-115-115-115-115-12

6        Water Quality Impact Assessment                                                                     6-1

6.1     Introduction                                                                                                          6-1

6.2     Assessment Approach                                                                                          6-1

6.3     Regulations, Standards and Guidelines                                                                   6-2

6.4     Baseline Conditions                                                                                              6-2

6.5     Impact Assessment & Evaluation                                                                           6-56-56-56-56-6

6.6     Cumulative Impacts                                                                                               6-56-56-56-56-7

6.7     Impact Mitigation & Residual Impact Assessment                                                    6-66-66-66-66-8

6.8     Environmental Monitoring & Audit (EM&A)                                                               6-66-66-76-76-9

6.9     Conclusions and Recommendations                                                                       6-66-66-76-76-9

6.10   References                                                                                                           6-76-76-76-76-9

7        Ecology                                                                                                                     7-1

7.1     Introduction                                                                                                          7-1

7.2     Assessment Approach                                                                                          7-1

7.3     Regulations, Standards and Guidelines                                                                   7-2

7.4     Ecological Baseline                                                                                               7-3

7.5     Ecological Impact Assessment & Evaluation                                                         7-157-157-157-157-16

7.6     Impact Mitigation & Residual Impact Assessment                                                  7-177-177-177-177-18

7.7     Environmental Monitoring & Audit Requirements                                                    7-177-177-177-177-18

7.8     Conclusions & Recommendations                                                                        7-187-187-187-187-19

7.9     References                                                                                                         7-187-187-187-187-19

8        Cultural Heritage Impact Assessment                                                             8-1

8.1     Introduction                                                                                                          8-1

8.2     Assessment Approach                                                                                          8-1

8.3     Regulations, Standards and Guidelines                                                                   8-1

8.4     Assessment Methodology                                                                                     8-2

8.5     Baseline Conditions                                                                                              8-3

8.6     Impact Assessment and Evaluation                                                                        8-4

8.7     Impact Mitigation & Residual Impact Assessment                                                    8-6

8.8     Environmental Monitoring & Audit                                                                           8-6

8.9     Conclusions & Recommendations                                                                          8-6

8.10   References                                                                                                           8-6

9        Implementation Schedule of Recommended Mitigation Measures              9-1

9.1     Introduction                                                                                                          9-1

10      Summary Conclusion & Recommendations                                                      10-1

10.1   Summary Conclusion of Technical Assessments                                                   10-1

10.2   Key Recommendations                                                                                        10-1

10.3   Summary of Environmental Outcomes                                                                   10-2

LIST OF FIGURES

Figure 2.1          Yung Shue Wan Helipad Siting Options

Figure 2.2          Yung Shue Wan Helipad – Site Location

Figure 3.1          Proposed Helipad Location and Environs

Figure 4.1          Representative Noise Sensitive Receiver Locations

Figure 4.2          Geographical Centres of Construction Activities

Figure 4.3          Approach and Departure Area and Surface Profile

Figure 4.4a        Illustration of Area Affected by Helicopter Manoeuvring Noise

Figure 4.4b        Illustration of Area Protected from Helicopter Approach / Departure Noise

Figure 4.4c        Helipad Relocation Distance Requirements to Eliminate Residual Helicopter Manoeuvring Noise

Figure 4.5          Helicopter Noise Validation Measurement Locations

Figure 6.1          Indicative Silt Curtain alignment Alignment during Marine Construction Works

Figure 7.1          Ecology & Water Quality Assessment Area and Sensitive Receivers

Figure 7.2          Habitat Map of the Yung Shue Wan Study Area

Figure 7.3          Habitat Photographs

Figure 8.1          Marine Geophysical / Marine Archaeology Survey Area and Sea Floor Features of Note


LIST OF TABLES

Table 2.1           Summary Matrix for Evaluation of Helipad Site Options & Alternatives

Table 2.2           Summary of Yung Shue Wan Helipad Construction Programme

Table 3.1           Hong Kong Air Quality Objectives

Table 3.2           Annual Average Pollution Concentrations Recorded in Tap Mun (Year 2002)

Table 4.1           Recommended Construction Noise Levels (Non-restricted Hours)

Table 4.2           Area Sensitivity Rating Criteria

Table 4.3           Acceptable Noise Levels in Leq(5 min) dB(A)

Table 4.4           Acceptable Noise Levels for Percussive Piling

Table 4.5           Helicopter Noise Standards for Planning Purposes

Table 4.6           Location of NSR Assessment Points in Yung Shue Wan

Table 4.7           Powered Mechanical Equipment to be used for Construction of Helipad

Table 4.8           Construction Activities

Table 4.9           Predicted Construction Noise Levels Leq(30 min) dB(A) - Unmitigated

Table 4.10         Helicopter Noise Data – Airborne Helicopter with Lateral Movements

Table 4.11         Measured Lmax Noise Level of GFS Helicopters – Without Lateral Movements

Table 4.12         Helicopter Use for Yung Shue Wan ‘Casevac’ Operations during years 2000 – 2004

Table 4.13         Worst-case Helicopter Noise Levels at NSRs during Helicopter Manoeuvring

Table 4.14         Worst-case Helicopter Approach / Departure Noise Levels at NSRs from the Super Puma AS332 L2 Type Helicopter

Table 4.15         Worst-case Helicopter Approach / Departure Noise Levels at NSRs from the EC155 B1 Type Helicopter

Table 4.16         Measured Lmax Levels

Table 5.1           Analytical Suite and Analytical Methods

Table 5.2           Sediment Quality Criteria

Table 5.3           Material Import Requirements

Table 5.4           Summary of Construction Phase Waste Generation

Table 6.1           Relevant Water Quality Objectives for Southern WCZ

Table 6.2           Summary of Water Quality at ‘SM5’ between 1999 and 2003

Table 7.1           Representative Species in the Ha Mei Wan Marine Benthic Community (CityU, 2002)

Table 7.2           Univariate Statistics for Ha Mei Wan & Similar HKSAR Survey Areas (CityU, 2002)

Table 7.3           Top Ten Ranked Adult Fish / Crustacean Families (from AFCD, 2003)

Table 7.4           Top Ten Adult Fish Species Caught off Yung Shue Wan (from AFCD, 1998)

Table 7.5           Hard Shore Benthic Fauna, Yung Shue Wan – Year 2001 Data (from Mouchel, 2002)

Table 7.6           Habitat Types in the Assessment Area

Table 7.7           Hard coral species, Yung Shue Wan (BMT, 27th April 2003)

Table 7.8           Ecological Evaluation of the Sub-tidal habitat

Table 7.9           Ecological Evaluation of the Granite Boulder Seawall

Table 7.10         Ecological Evaluation of the Hard Shore habitat

Table 7.11         Ecological Evaluation of the Developed / Disturbed Area

Table 7.12         Ecological Evaluation of the Mixed Scrub / Secondary Woodland habitat

Table 9.1           Air Quality – Implementation Schedule of Recommended Mitigation Measures

Table 9.2           Noise – Implementation Schedule of Recommended Mitigation Measures

Table 9.3           Waste Management – Implementation Schedule of Recommended Mitigation Measures

Table 9.4           Water Quality – Implementation Schedule of Recommended Mitigation Measures

Table 9.5           Ecology – Implementation Schedule of Recommended Mitigation Measures

LIST OF Appendices

Appendix 2.1     Visual Illustrations

Appendix 2.2     Construction Schedule

Appendix 4.1     Indicative Land Use Concept for Yung Shue Wan

Appendix 4.2     Construction Equipment Inventory

Appendix 4.3     Construction Noise Calculation – Unmitigated

Appendix 4.4     Helicopter Noise Measurement Points and Noise Levels

Appendix 4.5     Baseline Helicopter Noise Survey Report

Appendix 4.6     Helicopter Noise Calculations

Appendix 5.1     Sediment Classification Flow Chart

Appendix 5.2     Historical Marine Sediment Sampling Locations at Yung Shue Wan

Appendix 5.3     Sampling Programme and Chemical Screening Data at Yung Shue Wan

Appendix 6.1     Summary of Sediment Quality at Monitoring Station ‘SS4’ (1999 – 2003)


1                    Introduction

1.1               General

1.1.1          In August 2002 BMT Asia Pacific Limited (BMT) was awarded the contract for Agreement No. CE 18/2002: Environmental Impact Assessment Study for Construction of Helipads at Peng Chau and Lamma Island / Investigation by the Civil Engineering Office, Civil Engineering and Development Department (CEDD). 

1.1.2          The Agreement requires the completion of Environmental Impact Assessment (EIA) studies for two proposed helipads: one at Peng Chau and one at Yung Shue Wan, Lamma Island.

1.1.3          This Report presents the approach to and findings of the EIA study for the proposed Yung Shue Wan helipad, and follows the requirements of Environmental Impact Assessment Study Brief No. ESB-089/2001.

1.2               Project Background

1.2.1          The Project involves the construction and operation of a permanent helipad at Yung Shue Wan, Lamma Island, and is a ‘designated project’ under Item B.2, Schedule 2 of the Environmental Impact Assessment Ordinance (EIAO) by virtue of being: “A helipad within 300m of existing or planned residential development”.  Accordingly, an Environmental Permit is required for the Project.

1.2.2          The Project has been planned and managed in-house by the Land Works Division of CEDD on behalf of the Home Affairs Department (HAD). Construction works are to be completed by contractors under CEDD’s supervision. CEDD will hand over the helipad to the management department (yet to be determined) upon its commissioning.

1.2.3          The helipad is solely required for transporting residents in areas of North Lamma to urban areas for medical treatment in emergency situations, and is not for commercial use. The previous Yung Shue Wan helipad – located on a soccer pitch outside the North Lamma Clinic – ceased operation in May 1998 when the Government Flying Service (GFS) classified the Site to a Category 1 Landing Site.[*]

1.2.4          Since this time there has been no permanent, dedicated helipad serving the local community. The community was until recently using the helipad at The Hongkong Electric Co. (HEC) Ltd’s Lamma Power Station – a distance of 2.75 km and a typical trip time of around 20 minutes by mini-ambulance from the North Lamma Clinic.[†] As a more acceptable interim measure, HAD commissioned the development of a temporary helipad that has been in operation at Yung Shue Wan since October 2003 pending the construction of a permanent helipad to serve the local community [para. 2.2.34 refers]. 

1.2.5          A full description of the Project is presented in Section 2 112 of this Report.


1.3               Purpose and Approach of the EIA Study

1.3.1          The purpose of this EIA Study is to provide information on the nature and extent of environmental impacts arising from the Project and other concurrent works. This information will contribute to decisions by the Director of the Environmental Protection Department (EPD) 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 implementation of proposed mitigation measures.

1.3.2          Satisfying the aims of the EIA Study has been managed by achieving a number of more specific objectives as listed in the EIA Study Brief.  The objectives of the EIA study are to:

(i)                  Describe the proposed Project and associated works together with the requirements for carrying out the proposed Project;

(ii)                Consider alternative design and construction method(s) for the proposed Project and to compare the environmental benefits and disadvantages of each of the method(s) and design in selecting a preferred one;

(iii)               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;

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

(v)                Identify and quantify potential losses or damage to aquatic organism and natural habitats and to propose measures to mitigate these impacts;

(vi)              Identify and quantify potential losses or damage to flora, fauna and natural habitats and to propose measures to mitigate these impacts;

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

(viii)           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;

(ix)              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;

(x)                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;

(xi)              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.


1.4               Structure of this EIA Study Report

1.4.1          The EIA Report is divided into a total of 9 sections.  Following this Section 1, Introduction, the Report is organised as follows:

·            Section 2 – Project Description

·            Section 3 – Air Quality Impact Assessment

·            Section 4 – Noise Impact Assessment

·            Section 5 – Waste Management Assessment

·            Section 6 – Water Quality Impact Assessment

·            Section 7 – Ecology

·            Section 8 – Cultural Heritage Impact Assessment

·            Section 9 – Implementation Schedule of Recommended Mitigation Measures

·            Section 10 – Summary Conclusion & Recommendations

 

1.4.2          The respective assessments for each technical discipline follow the appropriate requirements as set out in the Technical Memorandum on Environmental Impact Assessment Process (EIA-TM).

1.4.3          For each section, all Figures are at the back of the section for ease of reference, while all Appendices are together at the back of the EIA Report.

 


2                    Project Description

2.1               Key Project Requirements

2.1.1          The fundamental Project requirements are the construction of an easily accessible and permanent helipad and an associated Emergency Vehicle Access (EVA) link with sufficient width to allow free movement of a mini-ambulance. The Fire Services Department has agreed to a 3.5 metres wide EVA for the Yung Shue Wan helipad. The GFS has also confirmed that a round helipad of 25 metres diameter is sufficient for helicopter operations.

2.1.2          The helipad is solely intended for emergency use and associated essential ‘casevac’ training flights, and will not be used for commercial operations.  As such, helipad use will be intermittent, with no fixed flight schedule.  The primary considerations for helipad development are flight operation safety and its accessibility by ground emergency vehicles from the Lamma Clinic in emergency situations. The helipad must also be operable and accessible at all times.

2.1.3          According to GFS Helipad Specification Guidelines, the guiding factors for siting a ‘surface-level helipad’ are as follows:

a)              The design and the location should be such that downwind operations are avoided and crosswind operations are kept to minimum to maximise helicopter manoeuvrability and operational safety.  It should have two approach surfaces, separated by at least 150 degrees (i.e., a minimum flight path angle of 150 degrees).

b)             The site should be conveniently situated as regards ground transport access mainly for emergency service (e.g. ambulance, fire engines) and adequate vehicle parking facilities.

c)             The ambient noise level should be considered near noise sensitive receivers, and especially in relation to areas below the helicopter approach / departure path(s). This means that the helicopter flight path should be situated away from residential areas as far as is practicable, and for this reason the flight path for the proposed Yung Shue Wan Helipad will approach and depart from the proposed helipad across the sea.

d)             Ground conditions beneath the take-off climb and approach surfaces should permit safe landings in the event of engine failure or forced landings during which injury to persons on the ground and damage to property is minimised.

e)              Consider, and assess with flight tests if necessary, the potential for and effects of eddies and turbulence that may be caused by any large structures close to the proposed helipad.

f)              Consider the presence of high terrain or other obstacles, especially power lines, in the vicinity of the proposed site that may pose a potential hazard.

2.1.4          As information on the usage frequency of the proposed Yung Shue Wan Helipad is critical for accurate operational phase impact assessment, relevant flight data from GFS for the 2000 – 2004 period has been reviewed (Table 4.12 refers).  Data for the year 2002 represents the greatest number of casevac flights in recent years, and so has been used as a basis for the impact assessment.

2.1.5          Information on possible future changes in the size of the resident population is also important, and the Notes of the draft Lamma Island OZP No. S/I-LI/6 (dated 1st April 2005) indicates a planned population of about 12,000 persons compared with the population of around 5,500 persons estimated from the 2001 Census. However, it is not anticipated that any such future population growth will significantly increase the population exposed to residual helicopter noise, given that the land closest to the proposed helipad has already been developed.

2.1.6          There is no specific data available on tourist visits to Lamma Island and there are no particular new tourist attractions to be developed, suggesting that tourism numbers are not anticipated to change significantly in the future.

2.2               Project History and Site Selection

Identification of Options / Alternatives

2.2.1          With reference to Clause 3.3 of the EIA Study Brief, a number of construction and operational scenarios have been considered for the Project, with the preferred option selected accordingly.  Consideration has been given to alternatives for:

(i)                                          Helipad location and EVA link alignment;

(ii)                                        Project design and construction methods; and

(iii)                                       Helicopter approach and departure paths.

2.2.2          As regards potential helipad siting options, three potential options identified through a site selection exercise initiated by the then District Planning Office (DPO) for Sai Kung & Islands (now DPO for Lantau & Islands) were taken forward for consideration: Option A, Option B (Alternative B1) and Option C.

2.2.3          A further four options / alternatives were identified under this Study for investigation: Option B (Alternative B2), Option D and Option E (Alternatives E1 and E2).

2.2.4          The characteristics of these seven options / alternatives that were taken forward for more detailed consideration are summarised below. Figure 2.1 shows the locations of the seven sites.

Option A: Yung Shue Wan North

2.2.5          The proposed ‘Option A’ site is located at the northern end of Yung Shue Wan, near the existing shoreline and adjacent to a public library. It is close to a number of residences that are located on the slope and foot of a hill.

Option B: Alternative B1 - Kam Lo Hom North

2.2.6          The proposed ‘Option B, Alternative B1’ site is situated at the edge of reclaimed land in the vicinity of Kam Lo Hom.

2.2.7          This option has the benefit of being adjacent to an existing EVA, but would require the development of the helipad platform in coastal waters and a short EVA link from the reclaimed land to the helipad.

Option B: Alternative B2 - Kam Lo Hom North (EVA Extension)

2.2.8          The proposed ‘Option B, Alternative B2’ site would involve extending the ‘Alternative B1’ EVA to locate the helipad beyond the helicopter noise ‘impact zone’ [Sub-section 4.6 refers].

Option C: Kam Lo Hom (South)

2.2.9          The proposed ‘Option C’ site is situated immediately southwest of and adjacent to the ‘Alternative B1’ helipad on a piece of recently reclaimed land.

2.2.10      The ‘Option C’ site is well located in terms of proximity to the North Lamma Clinic and distance from the built area, but most of the reclaimed land is already proposed for development of the Yung Shue Wan Sewage Treatment Works (STW) by the Drainage Services Department (DSD).

Option D: Ferry Pier

2.2.11      The proposed ‘Option D’ site is located at the roof of the existing Ferry Pier at Yung Shue Wan. The site would be accessible using the existing pier as an EVA. It is also in the vicinity of a number of residences and other Noise Sensitive Receivers.

Option E: Alternative E1 - Kam Lo Hom West (Marine EVA)

2.2.12      The proposed ‘Option E, Alternative E1’ site is located at the southwest of Kam Lo Hom, approximately 150 metres from the ‘Alternative B1’ helipad, to locate the helipad beyond the helicopter noise ‘impact zone’ [Sub-section 4.6 refers].

2.2.13      The ‘Alternative E1’ helipad would be accessed by way of a marine EVA to be constructed parallel to the existing sloping boulder seawall.

Option E: Alternative E2 - Kam Lo Hom West (Land EVA)

2.2.14      The proposed ‘Option E, Alternative E2’ helipad site is also located at the southwest of Kam Lo Hom, and would have the same footprint as the ‘Alternative E1’ helipad.   However, the ‘Alternative E2’ EVA would be land-based, being constructed around the back of the reclaimed land and the future STW.

Construction Methods

2.2.15      Three construction methods for forming the helipad platform and the EVA link have been considered and these are briefly summarised as follows:[‡]

·      Reclamation would require dredging of marine sediment to a suitable depth to allow construction of a stable foundation, followed by deposition of filling materials up to the required platform level.

·      Small diameter pre-bored piling method involves sinking a casing through the substrate and removing the material within.  Concrete is then poured into the casing to form the pile. A platform structure is then constructed on top of the piles.

·      Percussive piling involves driving steel piles into the bedrock. As the piles are driven through to the bedrock, sediments are laterally displaced without the need for dredging or excavation. A platform is constructed similarly as for the pre-bored piling method.

Community Consultation

2.2.16      Under the broader remit of the Assignment, the Consultants established a framework based on the basic principles of the EIA process that collectively aim to protect the environment through prevention.[§]

2.2.17      The evaluation framework comprised an initial assessment, mainly on environmental issues, through which environmental impacts were predicted through joint consideration of helipad location and construction method / programme.  This was followed by a Value Management (VM) exercise that involved consultation with, and direct participation of, the local community and other stakeholders at the early stage of the Project and before detailed technical assessment had been undertaken.

2.2.18      The VM exercise involved a forum with residents and community group members at a Yung Shue Wan Area Committee meeting in February 2003.  Nominees from this meeting attended a formal VM workshop in March 2003 whereat various evaluation criteria, including time frame, engineering feasibility, project cost, site availability, land ownership and community / social impacts were taken discussed and prioritised by participants.

2.2.19      The key community concerns raised through the VM exercise are listed below (in order of importance):

a.         Operational safety – the safety of the helicopter crew, passengers and the nearby community during helicopter activity was the main concern.

b.         Time frame – site availability and the speed of construction were raised as important factors due to the fact that the helipad is for emergency casualty evacuation.

c.         Direct ground access – given the inconvenience of the existing helipad, proximity to and availability of direct and uninterrupted access to the North Lamma Clinic is another issue of key concern.

2.2.20      ETWB Technical Circular (Works) No. 13/2003 on “Guidelines and Procedures for Environmental Impact Assessment of Government Projects and Proposals” (September 2003) promotes Continuous Public Involvement.  Accordingly, ongoing consultation has been conducted during the course of the study to present an update on progress, discuss key issues and to obtain stakeholder feedback.

2.2.21      At the most recent meeting with the Island District Council in February 2005, Council members reiterated their support for the proposed helipad and requested that the works commence as early as possible at the currently proposed site.  Community support for the project at the studied location was also reiterated at the North Lamma Rural Committee meeting in April 2005, and the Lamma Area Committee consultation in May 2005.

Evaluation of Options / Alternatives

2.2.22      A summary of the helicopter site option evaluation in relation to environmental benefits, dis-benefits and other key non-environmental considerations (e.g., access and safety issues) is presented in Table 2.1.  Elaboration on the factors affecting site selection is provided in the following paragraphs.

2.2.23      As the ‘Option A’ site is in close proximity to the built-up area of Yung Shue Wan and the helicopter approach and departure paths are partially obstructed by natural topography, this option is considered unsuitable by the GFS on flight safety grounds. Besides this, the proximity of this option location to the built-up area means that the residual helicopter noise levels from helicopter approach / departure to and from the helipad and from helicopter manoeuvring at the helipad would likely be unacceptably high.  Moreover, ambulance travel would be necessary along the narrow and sometimes busy Yung Shue Wan Main Street before it can reach the helipad from the Lamma North Clinic [Figure 2.1 refers]. This may cause undue delay in transporting patient to the helipad.

2.2.24      Most of the reclaimed land at Kam Lo Hom (South) has been scheduled for the development of the Yung Shue Wan STW [Sub-section 2.4 refers].  As such, sufficient land is not available for further development of the ‘Option C’ site into a helipad.

2.2.25      A helipad at the ‘Option D’ location was also considered unsuitable by the GFS on flight safety grounds due to the proximity of marine vessels, including public ferries and fishing boats, that are moored in the area which may infringe upon safe helicopter access / egress.  The ‘Option D’ site also suffers similar drawbacks to ‘Option A’ in terms of accessibility and its close proximity to residences.  Helicopter flight path noise and manoeuvring noise is also a key concern for this option due to the central location of this site in Yung Shue Wan and the absence of shielding / noise exposure of surrounding buildings.

2.2.26      The development of a helipad was considered at ‘Option E’ location at southwest Kam Lo Hom.  Two alternatives for EVA construction were reviewed: Alternative E1 by way of marine EVA, and Alternative E2 by way of a land-based EVA [Figure 2.1 refers].   The Alternative E1 EVA would pass in front of the proposed Yung Shue Wan STW and DSD has raised that this alignment is not acceptable as it would exclude access to the STW and prevent construction and maintenance of the proposed sewage outfall [Figure 2.1 refers].  As regards Alternative E2, this EVA route would encroach on undisturbed woodland at the foot of Kam Lo Hom and would require tree felling and land clearance and AFCD has stated that this alternative is undesirable in terms of nature conservation. For Alternative E1 there may also be potential impacts on hard corals found along the sloping boulder seawall due to construction and operation of the marine EVA [Figure 2.1 refers].

2.2.27      As regards the Option B alternatives, a helicopter noise level of up to 87 dB(A) has been predicted at the ‘Alternative B1’ location when the ‘Eurocopter EC 155B1’ type helicopter is in use (compared with the helicopter noise standard of 85dB(A)).  The helicopter noise level may reach 90 dB(A) when the preferred ‘Eurocopter EC 155B1’ type helicopter is not available for use, and the heavier / noisier ‘Eurocopter Super Puma AS332 L2’ type helicopter is in operation.  Accordingly, consideration was also given to extending the EVA to locate the helipad further away from the built environment and beyond the helicopter noise impact zone: ‘Alternative B2’.

2.2.28      It was found that in order to locate the helipad beyond the helicopter noise impact zone that the ‘Alternative B2’ EVA would need to be extended by approximately 270 metres from the ‘Alternative B1’ helipad location [Figure 2.1 refers].  Ultimately, as advised by the Marine Department, such a scenario was not preferred because the extension would reduce the area of navigable water between the Alternative B2 and the existing ferry pier. This would have the effect of increasing the proximity of marine traffic in those waters, and hence increase the risk of vessel collision.  Furthermore, Marine Department is of the view that in order to minimise the marine traffic risk the proposed helipad location should not extend any further offshore (i.e., from the proposed ‘Alternative B1’ location) [para. 4.6.24 and Figure 4.4c refer].

2.2.29      As regards the predicted helicopter noise level of 87dB(A) at ‘Alternative B1’ under ‘normal’ operating conditions (i.e., use of the ‘Eurocopter EC 155B1’), based on actual ‘casevac’ and flight data for the year 2002 the impact duration is predicted to last no longer than 5-10 seconds. The impact frequency (i.e., helipad use) is predicted to be once approximately every 3 days.  If the ‘Super Puma AS332 L2’ type helicopter were in operation then, while the noise level would increase to 90 dB(A), the impact duration would be 5-10 seconds and the impact frequency would be once approximately every 24 days [Sub-section 4.6 refers].

2.2.30      Consideration was given to implementing direct and indirect mitigation measures to satisfy the 85dB(A) helicopter noise standard.  As referred above with respect to ‘Option E’ and ‘Alternative B2’, there are various physical constraints that precluded these options / alternatives from development, including adverse landscape impacts, increased waste handling and habitat loss.

2.2.31      As the helipad is intended mainly for emergency use there is no fixed flight schedule.  As such, the use of indirect mitigation measures, such as improved window glazing and installation of air conditioners, was not considered feasible due to the short impact duration (<10 seconds) and unpredictable timing of helicopter operations at the proposed helipad [Sub-section 4.6 refers].

 


Table 222222.111111     Summary Matrix for Evaluation of Helipad Site Options & Alternatives

Option / Alternative

Location 1

Key Environmental Benefit(s)

Key Environmental Dis-benefit(s)

Other Key Considerations      (e.g., safety & access)

Conclusion

A

Yung Shue Wan North

·    No key environmental benefits.

·    Residual helicopter noise impacts from approach / departure to and from the helipad (i.e., flight path noise).2

·    Residual helicopter noise impacts from helicopter manoeuvring at the helipad.3

·    Construction noise impact.

·    Helicopter flight safety concerns due to proximity to built-up area in Yung Shue Wan.

·    Potential limitations on land accessibility from Clinic due to the narrow and sometimes busy Yung Shue Wan Main Street.

Unacceptable in terms of flight safety, accessibility and noise impacts.

B1

Kam Lo Hom North

·    No significant construction phase impacts.4

·    No helicopter flight path noise impact.5

·    Helicopter manoeuvring noise impact.6

·    Joint-closest to the Clinic (i.e., highly accessible).

Residual helicopter manoeuvring noise impact, but no construction or access concerns.

B2

Kam Lo Hom North

(EVA Extension)

·    No helicopter flight path or manoeuvring noise impacts.

·    Potentially significant visual impact from 270m long marine EVA.

·    Easy access from Clinic.

·    Marine safety risk (vessel collision) concerns due to EVA length.

Residual helicopter noise impacts unlikely to be significant, but unacceptable marine risk concerns.

C

Kam Lo Hom (South)

·    No significant construction phase impacts (land already formed).

·    Helicopter flight path or manoeuvring noise impacts unlikely to be significant.7

·    No key environmental dis-benefits.

·    Joint-closest to the Clinic (i.e., highly accessible).

·    Land required for proposed Sewage Treatment Works (STW).

Residual helicopter noise impacts unlikely to be significant, but site required for proposed STW development.

D

Ferry Pier

·    No key environmental benefits.

·    Helicopter flight path and manoeuvring noise impacts.

·    Construction noise impact.

 

·    Marine vessels by the ferry pier may infringe upon safe helicopter access / egress.

·    Potential limitations on land accessibility from Clinic due to the narrow and sometimes busy Yung Shue Wan Main Street.

Unacceptable in terms of flight safety, accessibility and residual helicopter noise impacts.

E1

Kam Lo Hom West

(Marine EVA)

·    Helicopter flight path or manoeuvring noise impacts unlikely to be significant.7

·    Potential impacts on hard coral found along the sloping boulder seawall due to construction and operation of the marine EVA.

·    Easy access from Clinic.

·    Prevents marine access to proposed STW; interferes with sewage outfall construction & maintenance.

Residual helicopter noise impacts unlikely to be significant, but unacceptable in terms of access to proposed STW and sewage outfall.

E2

Kam Lo Hom West

(Land EVA)

·    Helicopter flight path or manoeuvring noise impacts unlikely to be significant.7

·     Ecology impact from secondary woodland clearance.

·    Easy access from Clinic.

Residual helicopter noise impacts unlikely to be significant, but likely adverse ecological and landscape impacts.

 

1.        Figure 2.1 refers.

2.        Flight Path noise is the noise from the helicopter while in flight approaching to or departing from the helipad [Section 4.6.1 refers].

3.        Manoeuvring noise is the noise from the helicopter while manoeuvring on or directly over the helipad [Section 4.6.1 refers].

4.        A detailed Construction Noise Impact Assessment has been conducted and is presented in sub-section 4.5 of this EIA Report.

5.        A detailed Operational (Helicopter) Noise Impact Assessment has been conducted and is presented in sub-section 4.6 of this EIA Report [specifically, Tables 4.14 & 4.15 refer].

6.        A detailed Operational (Helicopter) Noise Impact Assessment has been conducted and is presented in sub-section 4.6 of this EIA Report [specifically, Table 4.13 refers].

7.        Based on the detailed Noise Impact Assessment in Section 4, these helipad locations are located sufficiently far from the built environment so as to avoid adverse noise impacts.


2.2.32      Overall, with the consideration of the residual helicopter noise impact on the local community, development of the ‘Option B, Alternative B1’ helipad location is preferred.  Reasons for preference of this option were its easy access from the North Lamma Clinic, avoidance of travel through the built-up and sometimes congested areas of Yung Shue Wan and, in particular, due to the relatively short time frame required for project development and availability for community use.  It is also noted that the proposed location provides a significant improvement in terms of helicopter noise levels than the soccer pitch in front of the Yung Shue Wan Clinic that was used as a landing site by GFS up to May 1998.

2.2.33      Evaluation of the construction options concluded that ‘Option B, Alternative B1’ could preferably be constructed by small diameter pre-bored piling. This offers a range of environmental benefits when compared to the dredge and reclaim method, and particularly with respect to waste management (Section 5), water quality (Section 6) and marine ecology (Section 7).  The main benefits of small diameter pre-bored piling relate to absence of marine dredging that minimises waste handling / management requirements. There will be minimal disturbance to the seabed from pile installation, and hence only highly localised water quality impacts and no marine ecology impacts are anticipated.

2.2.34      As the proposed helipad is urgently required, a temporary helipad was developed as an interim measure at the ‘Option C’ site location to meet the immediate need of the public and commenced operations in October 2003. This was possible as construction of the Yung Shue Wan STW is tentatively scheduled to commence in August 2007.  The cessation date of the operation of the temporary helipad stipulated in the condition of the Environmental Permit has recently been extended to 31 October 2006.

Design Refinements to the Preferred Option

2.2.35      Consideration has been given to means by which the design could be refined to minimise the scale and duration of the works and optimise the position of the helipad, and hence avoid or reduce the environmental impact potential. This approach of proactive avoidance and minimisation through design takes precedence over impact mitigation.

2.2.36      During the course of the Study, the following measures have been taken to refine the project design with a view to avoiding potential impacts:

·           The elevation of the helipad and EVA have been lowered as far as practicable in order to minimise their footprint, and hence the disturbance to the affected coastal waters.

·           The construction sequence shall be optimised to avoid cumulative construction noise effects with works for the proposed construction works of the Yung Shue Wan Sewage Treatment Works.

·           The construction method by small diameter pre-bored piling, as opposed to dredging and reclamation, was proposed. The benefits of the chosen construction method are summarised in para. 2.2.33.

·           The width of the EVA link has been reduced from the standard 4.5m to 3.5m, with the effect that material requirements for the project will be reduced as well as the footprint of the EVA on the seabed.

2.2.37      In addition, during the detailed design stage, effort shall be made to reduce the elevation of the proposed helipad platform as far as practicable while satisfying the engineering requirements to minimise visual impact. Futhermore, the position of the helipad shall be refined as far as practicable in order to optimise the shielding effect by natural topography on the helipad.

Operational Considerations

2.2.38      Helicopter noise is the main environmental concern during operation of the helipad.  It is predicted that there would be residual noise impact of up to 5 dB(A) at the nearby noise sensitive receivers (NSRs) under the worst-case scenario.  Based on worst-case GFS data for ‘casevac’ operations at Yung Shue Wan, the predicted frequency of the residual impact is approximately once every 3 days.  The impact duration would last for not more than 5-10 seconds per event.  A number of issues were considered in this regard, and are discussed in greater detail in Sub-section 4.6.  They include:

Helipad distance from the built environment:

2.2.39      There are severe constraints on land availability in Yung Shue Wan due to the need to satisfy the flight safety requirements [Section 2.1 refers]. In particular, there are restrictions on flight paths and helicopter manoeuvrability imposed by existing buildings, overhead power lines and high terrain.

2.2.40      It is required to minimise the noise impacts during helicopter operations as far as practicable. Based on the results of helicopter noise assessment, it was found that the helipad has to be at a minimum distance of 276m from the nearest Noise Sensitive Receiver in order to control the noise level to below 85dB(A) under normal operating conditions [para. 4.6.18 refers].[**]  On the other hand, there is need to minimise the travelling time from the Clinic to the helipad, bearing in mind it takes one minute for the mini-ambulance to travel approximately 200 metres.[††] A suitable balance must be struck between these conflicting requirements.

2.2.41      Having considered various factors of all the Options/Alternatives, ‘Option B, Alternative B1’ offers the best location as it is relatively close to the Clinic. Assessment results indicated that the helicopter noise impact due to flight path would comply with the noise criterion albeit the manoeuvring noise impact would exceed the criterion by up to 5 dB(A).

Helicopter Type

2.2.42      Consideration has been given to the use of helicopter types generating lower noise levels for casualty evacuation operations.  However, the GFS has confirmed that at present only the two helicopter types that have been assessed in this EIA Report (i.e., the ‘EC155 B1’ and ‘Super Puma AS332 L2’) are available for such operations.

2.2.43      For operational considerations, the GFS would not be able to exclude the use of the ‘Super Puma AS332 L2’, the noisier of the two helicopter types, from using the helipad although the GFS has agreed to give priority to the quieter ‘EC155 B1’ type helicopter for ‘casevac’ operations wherever practicable. This approach also follows the trend of current usage of the two helicopter types at Yung Shue Wan. As only one helicopter is able to operate at the helipad at any one time, no cumulative helicopter noise effects will be generated.  During the years 2003 and 2004, GFS has only used the smaller and quieter EC155 B1 type helicopter for night-time casevac operations and GFS has advised that this usage trend is expected to continue.

Helicopter Flight Path

2.2.44      The flight path is necessarily constrained by the flight safety requirements of GFS. The GFS guideline states that a surface level helipad should have two approach surfaces extending from the helipad.  In plan view, the centreline of the two flight paths should ideally be separated by at least 150 degrees so that should wind conditions impose constraints on flight safety (para 2.1.3a) refers) there is always one other option for safe helicopter approach / departure.

2.2.45      It was determined that a flight path separation angle of 150 degrees would adversely affect all residences at the residential area. With the agreement of GFS, the angle of separation between the two flight paths for the ‘Option B, Alternative B1’ site has been reduced to 80 degrees for use of ‘EC155 B1’ type helicopter and to 70 degrees for use of the ‘Super Puma’ [Figure 4.3 refers]. The re-aligned helicopter flight path will increase the distance between the noise source (helicopter) and the noise sensitive receiver (residential area) so that helicopter approach noise generated by both types helicopters can be reduced to within the 85dB(A) guideline at all noise sensitive receivers.

2.3               Project Characteristics and Site Location

2.3.1          The Project involves the construction of a helipad by small diameter pre-bored piling in coastal waters at Kam Lo Hom (North), Yung Shue Wan – ‘Option B, Alternative B1.  No dredging or reclamation works are required for the construction. Minimal excavation of slurry from within the pile casing will be required. However, this process will be an entirely contained activity, separated from the adjacent water column.

2.3.2          The project location was selected after detailed consideration of the operational requirements and environmental impact potential of developing the Project at each of seven site locations. With reference to the current statutory Lamma Island Outline Zoning Plan (No. S/I-LI/6), the proposed site is within a “Government, Institution or Community” (“G/IC”) zone and has been identified as a possible helipad. According to the Notes of the OZP, “Helicopter Landing Pad” is a Column 2 use that may be permitted with or without conditions on application to the Town Planning Board.

2.3.3          The helipad deck will be located approximately 25 metres from existing formed land, and an EVA link will be constructed to connect the proposed helipad with the existing EVA. Figure 2.2 shows the site location.

2.3.4          As referred under Clause 3.4.7 of the EIA Study Brief, visual illustration materials have been prepared to present the as-built appearance of the Helipad and EVA.  These materials are presented in Appendix 2.1, and specifically include a site layout plan, diagrammatic section, elevation and photomontages of the Helipad and EVA from 3 locations at Yung Shue Wan that are representative of the views that residents and visitors to Yung Shue Wan may encounter.  The perspective drawings referred to in the EIA Study Brief are considered not necessary as the 3 photomontages adequately illustrate the project appearance.

2.3.5          The site location was selected after due consideration of the operational requirements and environmental impact potential of constructing and operating the Yung Shue Wan helipad at each of four site locations. Specific Project details are as follows:

·    A total of approximately twenty-six numbers of small diameter pre-bored piles of about 610mm in diameter will be required for the construction of the helipad and EVA link.

·    The EVA link will be about 25 metres long and 3.5 metres wide, and will incline slightly from the existing formed land at 4.9 mPD to the helipad deck.

·    The helipad will have a diameter of 25 metres.

·    The helipad surface will be constructed to a height of about 7.85 mPD.

·    Railings will be installed along the EVA link, and wave deflectors will be installed around the helipad to enhance operational safety.

·    An off-site works area (including site office) to be located on the existing vacant land east of the Refuse Transfer Station will be required for approximately 2.3 years, from April 2006.[‡‡]

 

2.3.6          The construction programme can be broadly summarised as presented by Table 2.2Table 2.2Table 2.2Table 2.2Table 2.2Table 2.2Table 2.2Table 2.2.

Table 222222.222222     Summary of Yung Shue Wan Helipad Construction Programme

Construction Activity

Construction Period

Site Clearance

16-May-2006 to 22-Jul-2006

Mobilisation

24-May-2006 to 16-Aug-2006

Pile Installation

17-Aug-2006 to 27-Jan-2007

Helipad Construction

29-Jan-2007 to 22-Jun-2007

E&M Works

30-May-2007 to 5-Jul-2007

Demobilisation

6-Jul-2007 to 30-Jul-2007

 

2.3.7          Further details of the construction works are presented in Section 4, while the full construction programme is presented in Appendix 2.2.

2.4               Nearby Projects

2.4.1          Other projects identified in the vicinity that require consideration for the purposes of identifying and assessing as necessary the potential for cumulative effects.

Yung Shue Wan Development: Engineering Works, Phase 2

2.4.2          According to the tentative construction programme obtained from the Civil Engineering and Development Department, the Yung Shue Wan Development Engineering Works Phase 2 will not commence until Year 2008.  Therefore, there will be no potential cumulative effects.

Yung Shue Wan Sewage Treatment Works

2.4.3          The tentative schedule for the Drainage Services Department (DSD) to commence construction of the Yung Shue Wan STW is in August 2007, and works would last for about 3 years.  Therefore, the STW would not be constructed in parallel with the Helipad project. However, if the proposed helipad is still being constructed at the time that the STW construction commences, the existing temporary helipad will need to be relocated back to the Lamma Power Station, and this will cause a delay in casevac service.  As such, CEDD and DSD have agreed to avoid overlapping these two projects.  Even under the unlikely scenario that there are concurrent construction activities for the two projects, assessment results indicate that no adverse cumulative construction noise impacts are anticipated.

HEC’s Lamma Power Station Navigation Channel Improvement

2.4.4          Siltation in the main navigation channel leading to the HEC Lamma Power Station requires that maintenance dredging be conducted to ensure safe passage of coal delivery vessels.  HEC has advised that the works were completed in early 2004, and as such there will be no cumulative effects.

HEC’s Lamma Power Station Extension Works

2.4.5          The marine works for the Power Station Extension were completed in 2003 before the proposed navigation channel dredging period, and therefore there will be no cumulative effects.

2.5               Likely Future Environmental Conditions Without the Project

2.5.1          As the Helipad previously used by the community is located at the HEC Lamma Power Station – a distance of 2.75 km from Yung Shue Wan – there are presently no local environmental concerns that the Project will resolve / improve.

2.5.2          Without the Project the predicted operational helicopter noise impact would be avoided.  However, should the helipad not be developed, and upon the commencement of development of the Yung Shue Wan STW by DSD, the local community will be required to continue using the HEC helipad that requires ~20 minutes of travel time from the clinic [Para. 1.2.4 refers].  This would be an undesirable situation as the travel time to reach emergency services is unnecessarily prolonged.

2.5.3          Although there is an existing temporary helipad that has been in use since October 2003 that does not pose significant adverse environmental concerns, it is located at the proposed STW site and will need to close before STW construction can commence.  Based on consultations, this situation would not be acceptable to the local community unless the permanent helipad is in place.

2.5.4          Given the project nature and anticipated intermittence of helicopter use, with or without the project the ambient noise environment at Yung Shue Wan will remain rural in character.


3                    Air Quality Impact Assessment

3.1               Introduction

3.1.1          With reference to Clause 3.4.3 of the EIA Study Brief, the Applicant shall follow the requirements stipulated under the Air Pollution Control (Construction Dust) Regulation and propose any other remedies or mitigation measures in dust control to ensure that construction dust impacts are controlled within the relevant standards as stipulated in Section 1 of Annex 4 of the EIA-TM.[§§]

3.1.2          No operational Air Quality Impacts Assessment is required under the EIA Study Brief as the use of the proposed helipad will be limited, and there will be no other emissions associated with helipad operation.  No potential operational phase air quality impacts are anticipated.

3.2               Relevant Guidelines, Standards & Legislation

Air Pollution Control Ordinance (Cap. 311)

3.2.1          The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of stationary and mobile sources, including fugitive dust emissions from construction sites.  It encompasses Air Quality Objectives (AQOs) for 7 common air pollutants.  The AQOs are given in Table 3.1Table 3.1Table 3.1Table 3.1Table 3.1Table 3.1Table 3.1Table 3.1.

Table 333333.111111     Hong Kong Air Quality Objectives

 

Concentration (mg/m3)(1)  Averaging Time

Pollutant

1 Hour(2)

8 Hour(3)

24 Hours(3)

3 Months(4)

1 Year(4)

Sulphur Dioxide SO2

800

-

350

-

80

Total Suspended Particulates (TSP)

-

-

260

-

80

Respirable Suspended Particulates (RSP)(5)

-

-

180

-

55

Nitrogen Dioxide NO2

300

-

150

-

80

Carbon Monoxide CO

30000

10000

-

-

-

Photochemical Oxidants (as ozone(6))

240

-

-

-

-

Lead

-

-

-

1.5

-

Notes:

(1) Measured at 298 K and 101.325 kPa (one atmosphere).

(2) Not to be exceeded more than three times per year.

(3) Not to be exceeded more than once per year.

(4) Arithmetic means.

(5) Respirable suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 10 micrometers or less.

(6) Photochemical oxidants are determined by measurement of ozone only.

 

3.2.2          Section 1, Annex 4 of EIA-TM stipulates the hourly average Total Suspended Particulate (TSP) concentration of 500 mg/m3 measured at 298 K (25°C) and 101.325 kPa (1 atmosphere) for construction dust impacts.  Mitigation measures for construction sites specified in the Air Pollution Control (Construction Dust) Regulation should be followed.

3.2.3          The APCO subsidiary regulation Air Pollution Control (Construction Dust) Regulation defines notifiable and regulatory works activities that are subject to construction dust control.

Notifiable Works:

(a)        Site formation;

(b)        Reclamation;

(c)        Demolition of a building;

(d)        Work carried out in any part of a tunnel that is within 100 m of any exit to the open air;

(e)        Construction of the foundation of a building;

(f)        Construction of the superstructure of a building; or

(g)        Road construction work.

Regulatory Works:

(a)        Renovation carried out on the outer surface of the external wall or the upper surface of the roof of a building;

(b)        Road opening or resurfacing work;

(c)        Slope stabilisation work; or

(d)        Any work involving any of the following activities-

·          Stockpiling of dusty materials;

·          Loading, unloading or transfer of dusty materials;

·          Transfer of dusty materials using a belt conveyor system;

·          Use of vehicles;

·          Pneumatic or power-driven drilling, cutting and polishing;

·          Debris handling;

·          Excavation or earth moving;

·          Concrete production;

·          Site clearance; or

·          Blasting.

3.2.4          Notifiable works require that advance notice of activities be given to EPD.  The Regulation also requires the works contractor to ensure that both notifiable works and regulatory works will be conducted in accordance with the Schedule of the Regulation, which provides dust control and suppression measures.

3.3               Baseline Conditions and Air Sensitive Receivers

Existing Environment

3.3.1          The existing air quality within the Yung Shue Wan area is generally rural.  It is currently affected by the emissions from the Hongkong Electric Co. Ltd’s Lamma Power Station, which is approximately 800 m due southwest to Yung Shue Wan.  There are no major road networks within Lamma Island and therefore there are no vehicular emissions related air quality impacts. 

3.3.2          Environmental Protection Department (EPD) operates a network of Air Quality Monitoring Stations in Hong Kong, but none of these monitoring stations is located within or near Yung Shue Wan. As such, air quality data collected at the Tap Mun monitoring station in Sai Kung District – which resembles a rural area type setting similar to the environs of Yung Shue Wan – has been selected as being broadly representative of the existing ambient air quality conditions at Yung Shue Wan. These data are summarised in Table 3.2Table 3.2Table 3.2Table 3.2Table 3.2Table 3.2Table 3.2Table 3.2[***].

Table 333333.2222222     Annual Average Pollution Concentrations Recorded in Tap Mun (Year 2002)

Pollutants Monitored

Annual Average in micrograms per cubic metre

Respirable Suspended Particulates (RSP)

39

Sulphur Dioxide (SO2)

11

Nitrogen Dioxide (NO2)

13

Carbon Monoxide (CO)

688

Ozone (O3)

63

Notes:  

1.          All concentrations are measured at 298K (25°C) and 101.325KPa (one atmosphere)

2.               Data of the Tap Mun Monitoring Station are extracted from Air Quality in Hong Kong 2002, published by EPD 

 

3.3.3          The Hongkong Electric Co. Ltd. has operated an air quality monitoring station at Pak Kok San Tsuen on Lamma Island for a number of years.  The monitored SO2 and NO2 annual average concentrations in year 2002 are 11 mg/m3 and 25 mg/m3, respectively.  These results are comparable to the Tap Mun data.

Future Conditions

3.3.4          The Yung Shue Wan Phase 2 Reclamation will likely be a potential fugitive dust-polluting source during its works phase.  However, this will only be a short-term change in the ambient condition and will not alter the nature of the air quality condition of Yung Shue Wan once the works are completed.  Also it will commence after the completion of the helipad construction and therefore will not affect the background air quality condition during the helipad construction.  A small sand depot has been planned to locate in the Yung Shue Wan Phase 1 Reclamation area.

3.3.5          Based on the helicopter flight paths advised by GFS, helicopters will not over-fly the Phase 1 Reclamation area and the distance of the sand depot from the helipad would be too far for any dust (wind-blown sand) impacts to be generated.  As such, no adverse air quality (dust) impacts are anticipated from Project operation.  There are no distributor roads or other major infrastructure development planned in Yung Shue Wan and therefore, the air quality conditions are not expected to have any significant change in the future.

Air Sensitive Uses

3.3.6          Currently there are no occupied domestic premises in the immediate environs of the helipad site.  The potential air sensitive uses nearest to the helipad are an existing football field and the cluster of buildings near the football field, including low-rise (maximum 3-storey high) village houses, North Lamma Clinic, and a Tin Hau Temple.  These are generally located over 200 metres from the helipad site and over 50 metres from the off-site works area (adjacent to the refuse transfer station).  Village houses located along the coast of the Yung Shue Wan bay are also air sensitive uses  [Figure 3.1 refers].


3.4               Construction Dust Impact Assessment

Identification of Impacts

3.4.1          If uncontrolled, construction activities may result in construction dust impacts.  Construction of the helipad using a small diameter pre-bored piling method will include dust generation activities, some of which are notifiable / regulatory works.  They are described below.

3.4.2          The construction will begin with site clearance, including breaking a short section (approximately 15 metres length) of a landscape planter at the top of the seawall. This will be a regulatory works procedure that requires appropriate dust suppression measures under the Regulation to adequately control dust to within an acceptable level. 

3.4.3          Erection of site office, hoarding and fencing at the works area (approximately 50m x 25m) at the area adjacent to the refuse transfer station may involve very minor excavation that is regulatory work.  Dusty material stockpiling and handling will be done in the works area as well as at the site, for which dust control measures will be implemented.  Therefore dust will be controlled within acceptable level.

3.4.4          Pile installation for the EVA and helipad will be conducted through the water column, and therefore no dust impacts will arise.

3.4.5          The construction of the helipad deck and EVA may result in minor wind blown dust impacts.  However, this activity is a regulatory works procedure and requires proper suppression measures to control dust to within an acceptable level.

3.4.6          There may be use of trucks for material transport from the works area to the site via the short section of the existing concrete paved EVA.  Use of vehicles is a regulatory work procedure and the required dust control measures shall ensure dust levels are controlled to an acceptable level.

Cumulative Impacts

3.4.7          The construction of DSD’s Yung Shue Wan STW and Outfall is tentatively scheduled to commence in August 2007 for approximately 3 years.  The Helipad and STW developments have been scheduled to avoid concurrent works and cumulative air quality impacts.

Evaluation of Potential Impacts

3.4.8          The small diameter pre-bored piling works will be carried out entirely in coastal waters and no dust impacts are anticipated.  There will also be some minor works carried out at the off-site works area on existing ground adjacent to the refuse transfer station.

3.4.9          In view of small scale of the works, construction dust impacts can be controlled with appropriate implementation of dust suppression measures.   Moreover, dust control and suppression measures are statutory requirements under the Air Pollution Control (Construction Dust) Regulation.  As such, fugitive dust impacts during the construction can be adequately controlled and no significant impacts are anticipated.

 

 

 


3.5               Mitigation Measures

3.5.1          All the dust control measures as recommended in the Air Pollution Control (Construction Dust) Regulation, where applicable, should be implemented.  Typical dust control measures include:

·        The working area for site clearance shall be sprayed with water or a dust suppression chemicals immediately before, during and after the operation so as to maintain the entire surface wet.

·        Restricting heights from which materials are dropped, as far as practicable to minimise the fugitive dust arising from unloading/loading.

·        Immediately before leaving a construction site every vehicle shall be washed to remove any dusty materials from its body and wheels.

·        All spraying of materials and surfaces should avoid excessive water usage.

·        Where a vehicle leaving a construction site is carrying a load of dusty materials, the load shall be covered entirely by clean impervious sheeting to ensure that the dusty materials do not leak from the vehicle.

·       Travelling speeds should be controlled to reduce traffic induced dust dispersion and re-suspension within the site from the operating haul trucks.

·        Erection of hoarding of not less than 2.4 m high from ground level along the site boundary.

·        Any stockpile of dusty materials shall be either:

a)       Covered entirely by impervious sheeting;

b)      Placed in an area sheltered on the top and the 3 sides; or

c)      Sprayed with water or a dust suppression chemical so as to maintain the entire surface wet.

·          All dusty materials shall be sprayed with water or a dust suppression chemical immediately prior to any loading, unloading or transfer operation so as to maintain the dusty materials wet.

3.6               Environmental Monitoring and Audit Requirements

3.6.1          It is necessary to ensure proper implementation of the dust control measures as required under the Air Pollution Control (Construction Dust) Regulation.  No specific construction dust monitoring is necessary, although environmental audits will be carried out to ensure proper implementation of air quality control measures.

3.7               Conclusions and Recommendations

3.7.1          Through proper implementation of dust control measures as required under the Air Pollution Control (Construction Dust) Regulation, construction dust can be controlled to acceptable level and no significant impacts are anticipated.

 


4                    Noise Impact Assessment

4.1               Introduction

4.1.1          This Section provides an evaluation of the potential noise impacts associated with the construction and operational phases of the proposed development of a helipad at Yung Shue Wan, Lamma Island.

4.1.2          During the construction phase of the helipad, power mechanical equipment (PME) used for the helipad construction will be the primary noise sources.  The key noise generating activities include:

·         Site clearance for the erection of site office, hoarding and fencing;

·         Temporary staging construction and demolition;

·         Pile installation; and

·         Construction of helipad and EVA.

4.1.3          The helipad will solely be used for emergency use and associated essential ‘casevac’ training flights, and will not be used for commercial operations.  The sole noise source during the operational phase of the Project will be from helicopter activities, as follows:

·         Helicopter ‘approaching’ the helipad while it is descending at an angle to the helipad surface;

·         Helicopter manoeuvring on and directly over the helipad; and

·         Helicopter ‘taking-off’ from the helipad while it is climbing up at an angle to the helipad surface during departure.

4.1.4          Noise sensitive receivers (NSRs) have been identified in accordance with Annex 13 of the EIA-TM. As required under Clause 3.4.2.2 (iii) (b) of the EIA Study Brief, the selection of representative NSRs has been presented to and agreed by the Authority prior to commencement of this noise impact assessment.

4.1.5          Where appropriate, practicable mitigation measures are recommended to alleviate any potential noise impacts identified during both the construction and operational phases of the helipad so that the applicable noise guidelines and regulations can be achieved.

4.2               Relevant Guidelines, Standards & Legislation

Construction Noise During Non-restricted Hours

4.2.1          Noise arising from construction for designated projects during the non-restricted periods, i.e., between 07:00-19:00 hours of any days not being a Sunday or general holiday, is assessed with reference to the noise criteria listed in Table 1B, Annex 5 of the EIA-TM, which are summarised in Table 4.1Table 4.1Table 4.1Table 4.1Table 4.1Table 4.1Table 4.1Table 4.1.  These criteria shall be met as far as practicable according to Annex 5 of the EIA-TM.

Table 444444.111111     Recommended Construction Noise Levels (Non-restricted Hours)

Noise Sensitive Receiver Uses

Noise Levels Leq(30 min) dB(A)

All domestic premises including temporary housing accommodation, hotels and hostels

75

Schools

70 (normal school hours)

65 (during examination periods)

 


4.2.2          Subsidiary regulations of the Noise Control Ordinance (NCO) include the Noise Control (Hand Held Percussive Breakers) and Noise Control (Air Compressors) Regulations.  These require compliance with relevant noise emission standards and the fixing of noise emission labels to hand-held percussive breakers and air compressor.  Whilst these requirements are not directly relevant to the construction noise impact assessment, contractors must comply with these regulations during the construction phase.

Construction Noise During Restricted Hours

4.2.3          Construction noise is controlled during restricted hours, i.e., between 19:00-07:00 hours and on Sundays and public holidays (anytime for percussive piling), under the NCO and Technical Memoranda (TMs): Noise from Percussive Piling (PP-TM), Noise from Construction Work Other Than Percussive Piling (GW-TM) and Noise from Construction Work in Designated Areas (DA-TM).

4.2.4          A Construction Noise Permit (CNP) is required under the NCO for works involving the use of Power Mechanical Equipment (PME) during restricted hours.  The noise criteria for the use of PME during restricted hours are determined upon the Area Sensitivity Rating (ASR), which ‘ranks’ the background noise conditions of the area in which the NSR is located. Table 4.2Table 4.2Table 4.2Table 4.2Table 4.2Table 4.2Table 4.2Table 4.2 shows the ASR selection criteria as stated in GW-TM.

Table 444444.2222222     Area Sensitivity Rating Criteria

Type of area containing the NSR

Degree to which NSR is affected by IF(4)

Not Affected(1)

Indirectly Affected(2)

Directly Affected(3)

(i)   Rural area, including country parks or village type developments

A

B

B

(ii)  Low density residential area consisting of low rise or isolated high-rise developments

A

B

C

(iii) Urban area

B

C

C

(iv)  Area other than those above

B

B

C

Notes:

(1)         Not Affected means that the NSR is at such a location that the noise generated by the influencing factors(4) (IFs) is not noticeable at the NSR.

(2)         Indirectly Affected means that the NSR is at such a location that the noise generated by the IF, whilst noticeable at the NSR, is not a dominant feature of the noise climate of the NSR.

(3)         Directly Affected means that the NSR is in such a location that the noise generated by the IF is readily noticeable at the NSR and is a dominant feature of the noise climate of the NSR.

(4)         IFs are defined as industrial areas, major roads or the area within the boundary of Hong Kong International Airport.

            

4.2.5          The noise criteria for construction noise during restricted hours for each ASR are given in Table 4.3Table 4.3Table 4.3Table 4.3Table 4.3Table 4.3Table 4.3Table 4.3.

Table 444444.3333333     Acceptable Noise Levels in Leq(5 min) dB(A)

Time Period

Area Sensitivity Rating

A

B

C

All days during the evening (1900-2300) and general holidays (including Sundays) during the day and evening (0700-2300)

60

65

70

All days during the night-time (2300-0700)

45

50

55

 


4.2.6          Percussive piling is only permitted when the Noise Control Authority has granted a CNP.  PP-TM sets out the permitted hours of operation of percussive piling and Acceptable Noise Level (ANL) requirements, which are dependent on the architectural characteristics of the NSR.  The ANL criteria for percussive piling are reproduced in Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4.  ANLs for hospitals, schools, clinics, courts of law and other particularly sensitive receivers are 10 dB(A) below the figures quoted in Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4Table 4.4.

Table 444444.4444444     Acceptable Noise Levels for Percussive Piling

Architectural Characteristics of NSR

ANL, dB(A)

No windows or other openings

100

With central air conditioning system

95

With windows or other openings but without central air conditioning system

85

 

4.2.7          Regardless of any description or assessment made in the following paragraphs, in assessing a filed application for a CNP the Noise Control Authority will be guided by the relevant Technical Memoranda. The Authority will consider all the factors affecting their decision taking contemporary situations / conditions into account.  Nothing in this Report shall bind the Authority in making their decision, and there is no guarantee that a CNP will be issued.  If a CNP is to be issued, the Authority shall include any conditions they consider appropriate, and such conditions are to be followed while the works covered by the CNP are being carried out.  Failing to do so may lead to cancellation of the permit and prosecution action under the NCO.

4.2.8          There are some factors affecting the assessment results of a CNP application, such as the assigning of Area Sensitivity Rating, Acceptable Noise Levels etc.  The Noise Control Authority would decide these at the time of assessment of such an application based on the contemporary situations/conditions.  It should be noted that the situations / conditions around the sites may change from time to time.

Helicopter Noise

4.2.9          Table 1A, Annex 5 of the EIA-TM stipulates the noise standards of the helicopter noise (between 07:00 and 19:00 hours) for planning purposes.  These are summarised in Table 4.5Table 4.5Table 4.5Table 4.5Table 4.5Table 4.5Table 4.5Table 4.5.

Table 444444.5555555     Helicopter Noise Standards for Planning Purposes

Uses

Helicopter Noise Lmax dB(A)

07:00 to 19:00 hours

-       All domestic premises including temporary housing accommodation;

-       Hotels and hostels

-       Educational institutions including kindergartens, nurseries and all others where unaided voice communication is required

-       Place of public worship and courts of law

-       Hospitals, clinics, convalescences and home for the aged, diagnostic rooms, wards

85

Offices

90

Notes

(1)    The above standards apply to uses that rely on opened windows for ventilation.

(2)      The above standards shall be viewed as the maximum permissible noise levels assessed at 1 m from the external façade.

 


4.2.10      There are no specified evening/night-time noise guidelines for the HKSAR, and accordingly a document review of international practice was undertaken to determine international practice.  The review included the US Federal Aviation Agency (US FAA), the International Civil Aviation Organization, the US-based National Organization to Insure a Sound-controlled Environment (NOISE), and various individual airport / heliport web-sites.

4.2.11      From this review it was identified that most literature on aircraft noise concerns relates to commercial airplane and helicopter noise.  However, during the public consultation exercise for the ‘US FAA [public] Hearings on [non-military] Helicopter Noise’, there was a wide consensus among parties consulted that noise from emergency medical services was a tolerable necessity.[†††]  This situation also applies to existing casevac operations for Yung Shue Wan, which both GFS and CAD confirm have never received a noise complaint from the local community during day-time or night-time casevac operations.  With reference to the above consideration, the local environment and other EIA reports on helicopter noise, it is expected that the 85dB(A) Lmax could be one of the parameter to guage the possible noise impact on the residents during the evening period.  The current approach adopted in Hong Kong is to curfew the general commercial helicopter activities during night-time.

4.2.12      Recognising the tolerable necessity of emergency helicopter flights it was suggested during the FAA hearings that consideration be given to imposing some regulation on these operations to reduce noise impacts to NSRs.  Such consideration has been given during the course of this EIA Study in determining both the proposed helipad location and the proposed helicopter flight-path, and such details are provided in Sub-section 4.6.

4.3               Noise Sensitive Receivers

4.3.1          Noise sensitive receivers (NSRs) have been identified in accordance with the criteria set out in Annex 13 of the EIA-TM.  The spatial scope of the noise impact assessment shall include all areas within 300 metres from the Project boundary in accordance with the EIA Study Brief.

4.3.2          Site visits have been conducted to ensure the selection of existing representative NSRs.  A review of the latest Outline Zoning Plan (Lamma Island OZP No. S/I-LI/6), Outline Development Plan (Lamma Island ODP No. D/I-LI/2), and consultation with the Planning Department was conducted to identify the most likely location for future / potential future NSRs.

4.3.3          As required under Clause 3.4.2.2 (iii) (b) of the EIA Study Brief, the selection of representative NSRs has been presented to and agreed by the Authority prior to commencement of this noise impact assessment.  A brief description of existing and planned NSRs is provided below, while Figure 4.1 displays their locations.

Existing Noise Sensitive Uses

4.3.4          The majority of the developments along the coast of Yung Shue Wan are residential village houses, varying from single to 3 storeys high.  Some of these buildings are used for commercial purpose on the ground floor, e.g., grocery store and restaurant. There are isolated and dilapidated village houses located at the north of Kam Lo Hom (currently a “Green Belt” zone) that are not occupied, and hence are not noise sensitive.[‡‡‡]


4.3.5          The first tier buildings (i.e., those with a direct line of sight to the proposed helipad) will be the most affected by helicopter noise, but in turn they will provide some noise shielding to the second tier buildings (i.e., those buildings situated behind them). The natural topography of Kam Lo Hom also provides noise shielding to the buildings located south of the existing football pitch that are laterally the closest to the helipad site [Figure 4.1 refers].

4.3.6          The closest noise sensitive building with a direct line of sight to the helipad footprint is No. 105 Yung Shue Wan Main Street (NSR4), which is a residential village house about 220m southeast of the helipad site.  This NSR is considered as the worst-case as it is not shielded and will thus be directly affected by helicopter noise generated at the helipad.  At about 250m from the site, the North Lamma Clinic (NSR3) is the closest non-residential type NSR within direct line of sight of the helipad.

4.3.7          The cluster of buildings near the ferry pier also has direct line of sight to the helipad, of which the North Lamma Public Library (NSR2) is the closest to the helipad footprint at about 260m.  The North Lamma Public Library is also closest to the possible helicopter flight path to / from the helipad.  In addition, a village house at O Tsai (NSR1) has been selected as a representative residential type NSR.

Planned Noise Sensitive Uses

4.3.8          The main purpose of selecting planned NSRs is for the assessment of future noise impacts due to the operation of the helipad.  The current Lamma Island OZP has designated a “Comprehensive Development Area (1)” (‘CDA(1)’) zone for the land already reclaimed at the south of Yung Shue Wan and for the proposed reclamation under the Yung Shue Wan Phase 2 Reclamation project west of the bay.  Based on the latest information from the Planning Department [Appendix 4.1 refers], the scale of the Phase 2 Reclamation has been reduced and the Reclamation will not be developed to the extent outlined on the current approved OZP.

4.3.9          Planning Department has advised that the land use review on the reduced reclamation at Yung Shue Wan has been completed and amendment to the OZP would be made to reflect the land use changes.  Accordingly, the closest potential future NSRs would be near the existing football field and / or near the ferry pier (NSR5 and NSR6, respectively).  Planned NSRs will likely be residential type village houses (maximum building height of 3 storeys) to be constructed on available land lots in the existing “Village Type Development” (‘V’) zone.

4.3.10      The characteristics of NSRs in the vicinity of the proposed Yung Shue Wan Helipad are summarised in Table 4.6Table 4.6Table 4.6Table 4.6Table 4.6Table 4.6Table 4.6Table 4.6.  Figure 4.1 illustrates their locations.

Table 444444.6666666     Location of NSR Assessment Points in Yung Shue Wan

NSR Assessment Point

NSR Location

Number of storeys

Ground Level (mPD)

Land Use

NSR1

Village House at O Tsai

3

20.0

Residential

NSR2

North Lamma Public Library

1

4.0

Library

NSR3

North Lamma Clinic

1

3.3

Clinic

NSR4

No. 105 Yung Shue Wan Main Street

3

3.2

Residential

NSR5*

Future Development in “Village Type Development” Zone (near existing football pitch)

3#

3.1

Residential

NSR6*

Future Development in “Village Type Development” Zone (near existing ferry pier)

3#

15.5

Residential

Notes:

*           Future NSR.

#                  Assume a 3-storey high (8.23 m) residential building, based upon the most updated Lamma Island OZP No.S/I-LI/6 available (gazetted on 1.4.2005), excluding the proposed Yung Shue Wan Phase 2 Development.


4.4               Noise Environment at Yung Shue Wan

Existing Noise Environment at NSRs

4.4.1          Lamma Island is an outlying island with limited road network and has no major road traffic related noise sources.  However, it is observed from site visits that there are motorised carts travelling on access routes within the Yung Shue Wan area that may create noise disturbance. Yung Shue Wan is a popular tourist destination and the noise environment is dominated by human activities, with most activities during the daytime, and particularly at weekends and public holidays.

Future Trend

4.4.2          Based on the latest planning information, the Yung Shue Wan Phase 2 development work and Drainage Services Department’s (DSD’s) Yung Shue Wan Sewage Treatment Works (STW) will be potential noise sources.  During the Phase 2 development works and construction of the STW, NSRs close to the works site will be subject to construction noise, although upon completion of the works no significant change in the noise environment at Yung Shue Wan is anticipated.

4.5               Construction Noise Impact Assessment

Assessment Methodology

4.5.1          This construction noise impact assessment has been conducted based on the construction schedule and equipment inventory as presented in Appendix 2.2 and Appendix 4.2, respectively.  The construction schedule provided by CEDD is based upon all works to be undertaken during non-restricted hours only. Construction noise impacts at representative NSRs were assessed in accordance with Annex 13 of the EIA-TM.  The noise level at the most affected floor (i.e., 1/F) has been assessed and corrections such as façade correction and barrier correction have been applied as appropriate.

4.5.2          Based on the construction schedule, the noise assessment has been divided into 24 ‘assessment periods’ throughout the 18-month construction programme in accordance with the worst-case sound power level that may arise from the Site.  Each ‘assessment period’ represents a distinct construction task in the overall programme that can be used as a basis for construction noise impact assessment.

Identification of Potential Construction Noise Impacts

4.5.3          It is anticipated that the use of Powered Mechanical Equipment (PME) during the construction phase will generate potential noise impact upon the existing NSRs in the vicinity of the helipad site. Based on a practicable equipment inventory provided by the Project Proponent, Table 4.7 presents the likely PME that shall be used to construct the Project according to schedule and the corresponding sound power levels.


Table 444444.7777777     Powered Mechanical Equipment to be used for Construction of Helipad

Identification Code

Description

Sound Power Level, dB(A)

CNP 021

Bar bender (electric)

90

CNP 044

Concrete lorry mixer

109

CNP 047

Concrete pump, stationary/ lorry mounted

109

CNP 048

Crane, barge mounted (diesel)

112

CNP 061

Flat top barge

104

CNP 081

Excavator/ Backhoe

112

CNP 102

Generator, Silenced

100

CNP 068

Mini-truck

105

CNP 172

Vibrator

115

CNP 166

Piling, large diameter bored, reverse circulation drill

100

CNP 167

Auger

114

CNP 170

Poker, vibratory, hand-held

113

CNP 221

Tug boat

110

Source:  GW-TM and Sound power levels of other commonly used PME issued by EPD.

 

4.5.4          The entire construction sequence can be separated into four activities according to the construction schedule given in Appendix 2.2 and as summarised in Table 4.8Table 4.8Table 4.8Table 4.8Table 4.8Table 4.8Table 4.8Table 4.8.  The geographical centres of each activity for determining equipment locations (i.e., notional source position[§§§]) to calculate construction noise levels are presented in Figure 4.2.

Table 444444.8888888     Construction Activities

Construction Activities

Details of Works

Site Clearance

·          Erection of office, hoarding and fencing

Mobilisation

·          Plant set up;

·          Construction of working platform;

·          Mobilising and assembling of drilling machine; and

·          Ground investigation.

Pile Installation

·          Pre-drilling;

·          Drilling and installing casing;

·          Install H-pile;

·          Concreting; and

·          Preliminary/main pile test.

Helipad Construction

·          Construction of beams and slabs for helipad/EVA;

·          Construction of wave return walls for helipad/EVA; and

·          Road and drainage works.

E&M Works

·          E&M installation; and

·          E&M testing and commissioning.

Demobilisation

·          Demobilise the working platform and plant.

 


Prediction and Evaluation of Construction Noise Impacts

4.5.5          Based on the construction schedule and equipment inventory, the predicted unmitigated construction noise levels for each assessment period is summarised in Table 4.9.  Detailed calculations are presented in Appendix 4.3.

Table 444444.9999999     Predicted Construction Noise Levels Leq(30 min) dB(A) - Unmitigated

Assessment Period

NSR1

NSR2

NSR3

NSR4

NSR5

NSR6

1

59

60

69

71

69

60

2

66

68

71

73

71

67

3

65

67

71

73

71

66

4

65

67

71

73

71

66

5

68

69

72

74

72

68

6

64

66

67

69

67

65

7

64

66

67

69

67

65

8

60

61

63

64

62

60

9

60

61

63

64

62

60

10

63

64

66

67

65

63

11

67

68

70

71

69

67

12

66

67

69

70

68

66

13

68

69

71

72

70

68

14

67

68

70

71

69

67

15

66

67

69

70

68

66

16

65

66

68

69

67

65

17

60

61

63

64

62

60

18

68

69

71

72

71

68

19

68

69

71

72

71

68

20

68

69

71

72

71

69

21

68

69

71

72

71

69

22

59

60

62

63

62

59

23

52

53

55

56

54

52

24

63

64

66

67

65

63

Notes:   ‘Assessment Period’ refers to distinct construction tasks in the works programme [Appendix 2.2 refers].

 

4.5.6          The highest unmitigated construction noise level at the closest NSR (i.e., NSR4) is predicted to be 74 dB(A).  This level complies with the noise standard stipulated in Table 1B, Annex 5 of the EIA-TM.

Mitigation of Adverse Construction Noise Impacts

4.5.7          The predicted construction noise levels at representative NSRs comply with the noise standard. Therefore, no mitigation measures are required.  Nevertheless, it is recommended that the Contractor should adopt good working practices in order to minimise construction noise as far as possible:

a)       Noisy equipment and noisy activities should be located as far away from the NSRs as is practical;

b)      Unused equipment should be turned off;

c)      Powered mechanical equipment should be kept to a minimum and the parallel use of noisy equipment / machinery should be avoided;

d)      Regular maintenance of all plant and equipment; and

e)       The Contractor shall observe and comply with the statutory requirements and guidelines.

Cumulative Noise Impacts

4.5.8          As mentioned in Section 2 112, it is identified that the Yung Shue Wan Phase 2 Development Engineering Works will commence in Year 2008.  Therefore, there will be no cumulative impacts from the development works.  However, the completed Phase 1 reclamation immediately south of the proposed helipad is reserved for development of DSD’s Sewage Treatment Works (STW).  According to the preliminary STW construction programme, the 3-year construction period may commence in August 2007.  Therefore, both sites would not be constructed in parallel.

4.5.9          Furthermore, there is a temporary helipad currently operated by GFS at the STW site.  The permanent helipad will replace the temporary helipad for emergency casevac.  However, if the permanent helipad construction is not completed before STW construction commences, the temporary helipad will need to move back to the Lamma Power Station.  So as not to affect emergency helicopter services, CEDD and DSD have agreed to avoid any overlap in the development of these two projects.  As such, cumulative construction noise impacts are not anticipated.

4.6               Operational Noise Impact Assessment

Assessment Methodology

4.6.1          Noise associated with the proposed helipad at Yung Shue Wan will be generated during helicopter manoeuvring over the helipad and during lateral (approach / departure) flight. The different operational modes that may generate noise are summarised as follows:

Without Lateral Movements

Helicopter manoeuvring above the helipad within the Final Approach and Take-off Areas (FATO)[****] includes several modes:

·        ‘Hovering’ – helicopter turns on the spot over the helipad to achieve the desirable orientation for touchdown / lift-off;

·        ‘Touchdown’ – helicopter descends on to the helipad surface;

·        ‘Idling’ – helicopter remains on the helipad surface with its rotary blades kept running; and

·        ‘Lift-off’ – helicopter ascends vertically from the helipad surface to achieve a hover before departure.

 

With Lateral Movements

a)    Helicopter ‘approaching’ the helipad while it is descending at an angle to the helipad surface; and

b)   Helicopter ‘taking-off’ from the helipad while it is climbing up at an angle to the helipad surface.

 

4.6.2          According to Table 1A, Annex 5 of the EIA-TM, helicopter noise impacts shall be assessed in terms of the Lmax level, which is the maximum instantaneous sound pressure level at the noise sensitive receiver. Since all the identified NSRs are located at considerable distances (over 150 m) from the helipad, helicopter noise can be considered as a ‘point’ source.  Therefore, the sound pressure level at NSRs can be evaluated based on standard acoustic principle of a ‘point’ source, i.e., the sound pressure level in any direction (in the open) will decrease at a rate of 6 dB per doubling of distance away from the source.  The difference in noise levels at two different distances, r1 and r2, can be calculated using the following formula:

Noise Level Difference (dB) = 20 log10


4.6.3          Noise source terms (i.e., the Lmax at a given distance) of each helicopter operation mode has been provided by the Government Flying Service (GFS).  On site noise measurements have also been conducted to supplement the noise source terms data.

4.6.4          The International Civil Aviation Organization (ICAO) has stipulated noise standard for helicopters for different flying modes, including ‘approach’, ‘take-off’ and ‘flyover’ (i.e., the maximum noise level [in EPNdB] used as the noise certification standards adopted by the Council of ICAO).  The noise standards for the two types of GFS’ helicopter used for ‘casevac’ operations are summarised in Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10, with test noise measurement points for each flying mode illustrated in Appendix 4.4.  Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10 also presents the Demonstrated Noise Level data for the GFS helicopters as tested by the helicopter manufacturer (i.e., the noise level for that helicopter type measured by the manufacturer in accordance with standard technical procedures in the ICAO noise certification).

Table 444444.10101010101010   Helicopter Noise Data – Airborne Helicopter with Lateral Movements

Reference Measurement Configurations

Super Puma AS332 L2

EC155 B1

ICAO Max. Noise Level EPNdB

Demonstrated Noise Level EPNdB

ICAO Max. Noise Level EPNdB

Demonstrated Noise Level EPNdB

Approach

100.7 (87.7)

96.1 (83.1)

97.9 (84.9)

95.7 (82.7)

Take-off

99.7 (86.7)

94.6 (81.6)

96.9 (83.9)

92.2 (79.2)

Flyover

98.7 (85.7)

93.5 (80.5)

95.9 (82.9)

88.9 (75.9)

Notes:

Figures in brackets are the Lmax values.

Lmax = EPNdB – 13, with reference to the ‘Transportation Noise Reference Book’ (Nelson, 1987).

 

4.6.5          Based on the given noise data in Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10Table 4.10, the ‘approach’ mode generates the highest noise level when the helicopter is airborne with lateral movements.  Accordingly, the helicopter noise assessment makes reference to the ICAO standard for the approach mode that represents the worst-case scenario. By assessing the worst-case scenario any uncertainty in the quantitative prediction has been taken into consideration.

4.6.6          According to GFS Helipad Specification Guidelines, the helicopter approach and departure trajectory will be projected at an 8% slope within 245 metres from the edge of the helipad.  Beyond 245 metres the slope increases to 12.5%.  GFS has advised that the approach and departure angle is generally within the sector of 250-330 degrees from the centre of the helipad for the EC155 B1 type helicopter, and 250-320 degrees for the Super Puma AS332 L2 type helicopter [Figure 4.3 refers].  Accordingly, the closest distance between the airborne helicopter and the identified NSR (on the top floor) can be measured and used for evaluating the worst-case noise level.

4.6.7          The ICAO standards do not include standards for helicopter manoeuvring on and over the helipad, i.e., hovering, touchdown, idling and lift-off.  As such, on-site noise surveys on GFS’s helicopters were conducted at GFS helipad at Chek Lap Kok on 24th June 2003 to generate supplementary noise data.  The noise survey involved measuring the Lmax noise level generated by the GFS helicopters simulating manoeuvring on and over a helipad.  The measurements were taken at the far-field region such that the formula quoted below paragraph 4.6.2 can be applied.  The Lmax noise level measured has been used for assessing the worst-case scenario when the helicopter is at the helipad.   Details of the helicopter noise survey are provided in Appendix 4.5.

4.6.8          It was found that the Lmax noise level is less when the helicopter is idling (with rotors on) on the ground than the Lmax noise level occurs when the helicopter is in the air without lateral movements (either during hovering or lift-off mode). Table 4.11 displays the measured Lmax noise levels.


Table 444444.11111111111111   Measured Lmax Noise Level of GFS Helicopters – Without Lateral Movements

Measurement Configurations  (Reference distance: 150m)

Super Puma AS332 L2

EC155 B1

Helicopter on ground, Idling

82.0

80.0

Helicopter in the air *

90.6

87.7

Notes:

Lmax noise levels in dB(A).

* For ‘Super Puma AS332 L2’, the Lmax noise level was measured during the hovering mode.

For ‘EC155 B1’, the Lmax noise level was measured during the lift-off mode.

Identification of Potential Noise Impacts

4.6.9          Assessment of helicopter noise has been conducted for each of the operational modes as introduced in paragraph 4.6.1.

4.6.10      The GFS will use the proposed helipad for ‘casevac’ operations.   GFS helicopter fleet comprises two helicopter types: the ‘Super Puma AS332 L2’ and the ‘EC155 B1’.  The ‘Super Puma AS332 L2’ has a higher maximum operational weight than the ‘EC155 B1’, and hence operates at a higher power output and generates a higher noise level.  However, GFS has agreed to deploy the ‘EC 155 B1’ type helicopter whenever possible for ‘casevac’ operations, and only under very special circumstances shall the ‘Super Puma AS332 L2’ be deployed.

4.6.11      The Super Puma was introduced into the GFS helicopter fleet in November 2001, while the EC155 B1 was introduced into the GFS fleet in November 2002.  Prior to this time the GFS relied on Sikorsky S76 / Sikorsky S70 type helicopters for casevac operations, and these were phased out during 2003. Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12 summarises actual GFS helicopter usage data for ‘casevac’ operations from 2000 through 2004.

Table 444444.12121212121212   Helicopter Use for Yung Shue Wan ‘Casevac’ Operations during years 2000 – 2004

Year

Total No. of Casevac from  0700 to 2200 hours1

Total No. of Casevac from 2200 – 0700 hours2

No. of Casevac Training Flights3

2000

51 (1)

30

3

2001

69 (7)

39

4

2002

104 (13)

37

6

2003

92 (7)

34

5

2004

66 (1)

29

4

Notes:

1.        The figures in brackets ( ) are the number of casevac flights carried out by Super Puma (or Sikorsky prior to 2004).

2.        Since 2003, all night-time casevac has been undertaken using the EC155 B1 type helicopter only, although for the purpose of this noise impact assessment it cannot be discounted that the Super Puma may be required for night-time casevac in future years.

3.        Five casevac-training flights were conducted to the Yung Shue Wan helipad in 2003 (i.e., an additional 4% of the total casevac flights).  As no such data is available for other years, the number of casevac training flights for 2000-2002 and 2004 have been calculated using the same % contribution.  It should be noted that GFS does not anticipate any increase in training flights in the short to medium term as the helicopter fleet was upgraded in 2001/02 and there are no plans to add additional types of helicopters.’

4.6.12      Using the flight data for the year 2002 as a worst-case scenario, it has been assumed that there may be a total of 147 flights in a single year.  Of this total it has been assumed that the ‘Super Puma’ would be operated for up to 13 casevac flights a year.  In the absence of a specific data breakdown, it has also been assumed that two of the six training flights would be using the Super Puma.  Overall, as a worst-case scenario it is assumed that the Super Puma would be used on no more than 15 occasions in a year: equivalent to one flight every 24.3 days.


4.6.13      Using the same calculation method, and including all nigh-time flights, it has been assumed that the EC155 B1 type helicopter would be used for casevac at Yung Shue Wan on no more than 132 occasions in a year: equivalent to one flight every 2.8 days.

Cumulative Helicopter Noise Impacts

4.6.14      Upon commencement of operations at the proposed Yung Shue Wan helipad, use of the currently temporary landing site on the future STW will cease.  The HEC helipad located approximately 800 metres southwest of the proposed helipad is infrequently used.  In addition, GFS also confirmed that only one helicopter will use the helipad at one time and therefore no cumulative noise impacts are anticipated.

4.6.15      There is no other significant noise source in the area that may contribute to a cumulative operational noise effect.

Prediction and Evaluation of Noise Impacts

Without Lateral Movements

4.6.16      The assessment of helicopter noise generated at the helipad is based on the Lmax noise levels of the helicopter manoeuvring over the helipad and the horizontal separation between the helipad and identified NSRs. Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13 summarises the calculated Lmax noise levels at the identified NSRs.  Details of the calculation are provided in Appendix 4.6.

Table 444444.13131313131313   Worst-case Helicopter Noise Levels at NSRs during Helicopter Manoeuvring

NSR ID

Horizontal separation to centre of the Helipad (metres)

Lmax @ NSR dB(A) 1

Façade Correction dB(A)

Corrected Lmax @ NSR dB(A)

Super Puma AS332 L2

EC155 B1

Super Puma AS332 L2

EC155 B1

NSR1

301

85 (76)

82 (74)

3

88 (79)

85 (77)

NSR2

257

86 (77)

83 (75)

3

89 (80)

86 (78)

NSR3

246

86 (78)

83 (76)

3

89 (81)

86 (79)

NSR4

221

87 (79)

84 (77)

3

90 (82)

87 (80)

NSR5*

263

86 (77)

83 (75)

3

89 (80)

86 (78)

NSR6*

292

85 (76)

82 (74)

3

88 (79)

85 (77)

Notes:

1 Calculated with reference to measured Lmax noise level at reference distance of 150m.

*  Future NSR.

Figures in brackets are the Lmax during the idling mode.

Bold figures indicate exceedance of the Lmax 85 dB(A) limit.

 

4.6.17      The evaluation results in Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13Table 4.13 show that the worst-case Lmax noise level during helicopter manoeuvre above the helipad will be 90 dB(A) at NSR4 when a ‘Super Puma AS332 L2’ helicopter is in hovering mode, and 87 dB(A) when an ‘EC155 B1’ helicopter is lifting off (i.e., ascending vertically) from the helipad.  With both helicopter types the worst-case Lmax exceeds the 85 dB(A) limit.  The worst-case Lmax noise level during the idling mode is less than the 85 dB(A) limit for both helicopter types.

4.6.18      It has been calculated that during helicopter manoeuvring, the minimum distance separation between the helipad and an NSR to comply with the 85 dB(A) helicopter noise limit is 386m for the ‘Super Puma AS332 L2’ in hovering mode, and 276m for the ‘EC155 B1’ in lift-off mode [Figure 4.4a refers].


With Lateral Movements

4.6.19      Regarding the helicopter approach mode, the projected worst-case trajectory of the approach path (i.e., closest to the NSR), is at the line with a bearing of 330 degrees to the centre of the helipad for ‘EC155 B1’ helicopters and 320 degrees for ‘Super Puma AS332 L2’ helicopters.  NSR1, NSR2 and NSR6 are closest to the approach path and will therefore be the most affected by helicopter noise during approach.

4.6.20      Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14 and Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15 display the worst-case Lmax noise levels based upon the closest slant distance between the helicopter and the top floor of the NSRs. Calculations are based on the ICAO maximum noise level.  Calculation details are provided in Appendix 4.6.

Table 444444.14141414141414   Worst-case Helicopter Approach / Departure Noise Levels at NSRs from the Super Puma AS332 L2 Type Helicopter

NSR ID

Slant distance between helicopter & NSR (metres)

Lmax @ NSR dB(A) 1

Façade Correction dB(A)

Corrected Lmax @ NSR dB(A)

NSR1

253

81

3

84

NSR2

226

82

3

85

NSR3

246

82

3

85

NSR4

221

82

3

85

NSR5*

263

81

3

84

NSR6*

281

80

3

83

Notes:

1 Calculated with reference to ICAO maximum noise level (i.e., noise standard) at reference distance of 120m.

* Future NSR.

 

Table 444444.15151515151515   Worst-case Helicopter Approach / Departure Noise Levels at NSRs from the EC155 B1 Type Helicopter

NSR ID

Slant distance between helicopter & NSR (metres)

Lmax @ NSR dB(A) 1

Façade Correction dB(A)

Corrected Lmax @ NSR dB(A)

NSR1

220

80

3

83

NSR2

201

80

3

83

NSR3

246

79

3

82

NSR4

221

80

3

83

NSR5*

263

78

3

81

NSR6*

261

78

3

81

Notes:

1 Calculated with reference to ICAO maximum noise level (i.e., noise standard) at reference distance of 120m.

* Future NSR.

 

4.6.21      With reference to Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14Table 4.14 and Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15Table 4.15, the worst-case Lmax noise level for the helicopter approach mode complies with the 85 dB(A) limit for both ‘EC 155 B1’ and ‘Super Puma AS332 L2’ helicopters.  Note that while compliance with the 85 dB(A) daytime standard is anticipated, helicopter noise nuisance may still be experienced.

Mitigation of Adverse Noise Impacts

4.6.22      Noise levels from helicopter manoeuvring over the helipad will likely exceed the Lmax 85 dB(A) limit at some NSRs for both helicopter types.  Accordingly, the feasibility of adopting various direct mitigation measures has been investigated with reference to Annex 13 of the EIA-TM.  These measures are discussed below. As the predominant user of the proposed helipad, GFS has been consulted on the various measures and has advised on the practicality of mitigation measures in terms of helicopter operations, as appropriate.


Alternative land use arrangement and siting:

4.6.23      With reference to the current statutory Lamma Island Outline Zoning Plan OZP No. S/I-LI/6, the selected helipad site is located within a “Government, Institution or Community” (“G/IC”) zone.    According to the Notes of the OZP, Helicopter Landing Pad is a column 2 use that may be permitted with or without conditions on application to the Town Planning Board. This site is considered to be optimally located in terms of operational safety, accessibility from the North Lamma Clinic and environmental implications.

4.6.24      In order to completely contain the helicopter noise (i.e., manoeuvring noise) to within the 85dB(A) standard, relocating the helipad approximately 80 metres further westwards from the proposed ‘Option B, Alternative B1’ site was considered: ‘Option B, Alternative B2’.  A total EVA extension of 270 metres would be required to eliminate manoeuvring noise from the ‘Super Puma’ type helicopter due to its higher noise level (i.e., the helipad would have to be located ³386m from the nearest NSR within direct line of sight).[††††]  However, the marine traffic risk related to an EVA extension of 270m is not preferred by the Marine Department as it would reduce the area of navigable water between the ‘Option B, Alternative B2’ and the existing ferry pier, thereby increasing the proximity of marine traffic and the risk of vessel collision.  Furthermore, Marine Department is of the view that in order to minimise the marine traffic risk the proposed helipad location should not be extended any further offshore from the proposed ‘Option B, Alternative B1’ location [Figure 2.1 refers].

4.6.25      Considering the potential increase of marine traffic risk and delay of helipad, further offshore extension of the EVA from the proposed ‘Option B, Alternative B1’ is infeasible.

4.6.26      In order to completely contain the helicopter noise to within the 85dB(A) standard, relocating the helipad approximately 150 metres further to the southwest from the proposed ‘Alternative B1’ site was considered (i.e., ‘Option E’).  However, such relocation via a marine EVA (i.e., ‘Alternative E1’) would place the EVA directly in front of the proposed Yung Shue Wan STW, and across the proposed marine outfall from the STW.  Such an arrangement is not supported by Drainage Services Department as it would impede construction and maintenance of the marine outfall, and would prevent marine access to the proposed STW.  The land-based EVA (i.e., ‘Alternative E2’; Figure 2.1 refers) would encroach on undisturbed woodland at the foot of Kam Lo Hom requiring tree felling and land clearance, and AFCD has stated that this alternative is undesirable in terms of ecology / nature conservation.

Screening by Noise Tolerant Buildings

4.6.27      The nearby Refuse Transfer Station (RTS) could be a noise tolerant building approximately 6 metres high, but it is not a solid structure that can form an effective noise screen to NSRs 3-5.  The land area around the proposed helipad Site is limited, and there are no options to construct any noise tolerant buildings in the vicinity in the future due to the lack of land.  Moreover, development of any buildings in the vicinity of the proposed helipad may also introduce constraints on flight safety.


Setback

4.6.28      The proposed helipad does not involve any building development, so building setback is not relevant.

4.6.29      A smaller re-positioning of the proposed Option B, Alternative B1 location from the “G/IC” zone gazetted for the helipad on the latest OZP was also investigated. The objective was to further refine the proposed location to optimise shielding of NSRs by the natural topography of the Kam Lo Hom headland.  However, a minimum shift of 25m further west would be required to reduce residual noise impacts on approximately eight NSRs.  Ultimately, such as shift would require amendment of the OZP under Section 12A of Town Planning (Amendment) Ordinance 2004, and would delay project implementation and may infringe marine access to the proposed STW.

Decking Over

4.6.30      This measure relates to road traffic noise control and is not applicable to helicopter noise control.

Extended Podium

4.6.31      The proposed helipad does not involve any building development. This option is not applicable.

Building Orientation

4.6.32      The proposed helipad does not involve any building development, so this measure is not applicable.

Treatment of Source

4.6.33      GFS has agreed to give priority to deploying the quieter ‘EC155 B1’ type helicopter for ‘casevac’ and emergency operations at Yung Shue Wan wherever practicable [Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12Table 4.12 refers]. However, it is not possible to exclude the ‘Super Puma’ from using the helipad in serious emergency situations when a larger capacity helicopter type is required. As the ‘Super Puma’ and ‘EC155 B1’ type helicopters were only introduced into GFS fleet late in 2001 and 2002 respectively, there are no plans at this time to replace the existing helicopter fleet.

Alternative Alignment

4.6.34      GFS has already agreed to reduce the angle of the helicopter flight path from the standard 150 degrees to 80 degrees for the ‘EC155 B1’ and to 70 degrees for the ‘Super Puma AS332 L2’ helicopter.  This re-alignment had the effect of increasing the distance between the noise source (helicopter) and the noise sensitive receiver (residential area) so that helicopter approach / departure noise was reduced to within the 85 dB(A) standard [Figure 4.4(a) refers].  Thus, this measure has effectively eliminated the residual helicopter flight path noise impacts on approximately 420 noise sensitive dwellings during approach / departure of the ‘EC155 B1’ type helicopter and on approximately 300 noise sensitive dwellings during approach / departure of the ‘Super Puma’ type helicopter [Figure 4.4(b) refers].

4.6.35      A further reduction in the flight path angle cannot eliminate the residual helicopter manoeuvring noise that is generated by the helicopter on or over the helipad surface. The only way manoeuvring noise can be reduced / eliminated is to locate the helipad further from noise sensitive buildings [paras. 4.6.234.6.27 refer].

Noise Barrier / Enclosure

4.6.36      In the case of the Yung Shue Wan helipad, physical structures such as noise barriers / enclosures cannot be constructed to provide effective noise shielding of the helicopter noise. This is because the noise is airborne (at an elevation of approximately 17 mPD) and will be emitted when the helicopter is at a linear distance of approximately 30 metres from the helipad.

Special Building Design

4.6.37      The proposed helipad does not involve any building development, and therefore this measure is not applicable.

Architectural Features / Balcony

4.6.38      The proposed helipad does not involve any building development, and therefore this measure is not applicable.

Open-textured Road Surfacing

4.6.39      This measure is not applicable to helicopter noise control.

Indirect Mitigation Measures

4.6.40      The application of indirect mitigation measures would require installation of acoustic insulation into all NSRs at which the predicted Lmax exceeds 85 dB(A). Effective indirect mitigation requires that NSR occupants comply with a ‘closed-window’ living environment during helicopter manoeuvring.

4.6.41      It is considered that such measures would not be effective, as residents would receive no prior notice of an impending helicopter arrival.  In addition, the short impact duration (5 – 10 seconds) means that the impact event would be over by the time a response could be made.  Accordingly, mitigation measures would not be a practicable means of noise mitigation and they are not recommended.

Evaluation of Residual Impacts

4.6.42      Adverse helicopter noise impact is not anticipated due to the short impact duration of 5 – 10 seconds.  The significance of the residual helicopter noise impact has been considered in accordance with appropriate factors referred to under section 4.3.3 of the TM on the EIA Process, as set out below.

Effects on public health and Risk to life

4.6.43      In terms of effect on public health, the proposed helipad location and flight path will reduce the ambient noise level on the exposed community compared with the currently tolerated situation. As regards the duration of the residual impact, it is known that the sense of hearing becomes less acute when the ear is exposed to intense loud noise for a period of time (Ward et al, 1959). Furthermore, the Factories and Industrial Undertakings (Noise at Work) Regulation (CAP 59T) established a daily personal exposure (Lepd) noise level of 85 dB(A), meaning that a person exposed to noise level of 85dB(A) for 8 hours may require hearing protection.[‡‡‡‡]  As a basis for comparison only, the anticipated duration of the residual helicopter noise impact will be no more than 10 seconds, equivalent to a Lepd of 51 - 55 dB(A). As such the effect of the residual helicopter noise on public health will be insignificant.

4.6.44      As regards risk to life, the proposed helipad is not a hazardous source and there shall be no storage of fuels or other dangerous goods at the site. There is also no risk to life associated with the construction of the helipad. However, it is considered that the improved access to urban areas for medical treatment in emergency situations that the proposed helipad offers when compared with the previous reliance on HEC Ltd’s Lamma Power Station may potentially decrease the risk to life.

Magnitude, duration and frequency of Impact

4.6.45      After taking into account all the practicable direct mitigation measures, the worst-case Lmax noise levels are predicted to be 90 dB(A) [residual noise is 5 dB(A)] resulting from hovering of a ‘Super Puma AS332 L2’ type helicopter and 87 dB(A) [residual noise is 2 dB(A)] due to lift-off by a ‘EC155 B1’ type helicopter at NSR4.  The noise impact duration will last 5-10 seconds according to GFS. No adverse helicopter idling noise impact is predicted.

4.6.46      It should be noted that GFS primarily uses the EC155 B1 type helicopter for casevac operations at Yung Shue Wan. With reference to the casevac data from GFS for the period 2000-2004, the flight frequency of the Super Puma and EC155 B1 type helicopter is equivalent to one flight every 24.3 days and 2.8 days, incurring a maximum 5 dB(A) and 2 dB(A) exceedance of the 85 dB(A) limit, respectively.  The duration of the residual impact would be 5-10 seconds per event.

4.6.47      GFS has been directly consulted throughout the preparation of this EIA study report, and being fully aware of the residual helicopter noise issue, has expressed a willingness to avoid use of the Super Puma whenever practicable (i.e., provided the ‘EC155 B1’ is available).  Based on actual GFS casevac data for 2003 and 2004, only the ‘EC155 B1’ has been used for night-time casevac.  However, it cannot be discounted that under special circumstances (e.g., large-scale emergency) the use of the ‘Super Puma’ may be required for night-time casevac.

Geographic extent and likely size of community that may be affected

4.6.48      The first tier buildings with facades directly facing the Yung Shue Wan bay area would likely be subject to the residual helicopter noise impact.  Approximately 75 dwellings within 276 metres of the helipad, and with a direct line of sight, would be affected during lift-off of the ‘EC155 B1’ type helicopter.  Similarly, approximately 360 dwellings located at or within 386 metres, and with a direct line of sight, of the helipad would be affected by the ‘Super Puma AS332 L2’ type helicopter during hovering.  Figure 4.4(a) displays the locations of these noise sensitive buildings.

4.6.49      With reference to the Notes of the draft Lamma Island OZP No. S/I-LI/6 (dated 1st April 2005), it indicates the planned population for Lamma Island of about 12,000 persons compared with the population of around 5,500 persons.  However, it is not anticipated that any such future population growth will significantly increase the population exposed to residual helicopter noise, given that the land closest to the proposed helipad has already been developed.

4.6.50      The predicted residual helicopter noise impacts associated with the proposed helipad operation will only occur locally, i.e., at Yung Shue Wan and within an affected zone.  There will be no spread of such noise impacts elsewhere.

Reversibility of Impact

4.6.51      The operational helicopter noise impact shall be reversible.  The impact will occur on a less than daily basis, and each residual impact event shall be of short duration.

Other Considerations

4.6.52      Consideration had been given to eliminating this residual noise impact altogether, such as relocating the proposed helipad further north or west.  However, such proposals are not acceptable due to environmental, risk and accessibility concerns.


4.6.53      Consideration has been given to constructing physical structures such as noise barriers / enclosures to provide effective noise shielding of the helicopter noise (para.section 4.6.36), although the erection of such structures is not practicable. Taking into account the various other mitigation measures that have been considered / adopted as outlined in para.sections 4.6.22 to 4.6.41, it would appear that there would still be a residual noise impact of up to 5 dB(A). Considering that this residual noise impact is of short duration, lasting < 10 seconds per event, as well as occurring only once about every 2.8 days for EC155 B1 and 24.3 days for Super Puma, this will not cause long term noise nuisance to the nearby affected residents.

4.6.54      As residual noise may be audible during night-time from 7pm to 7am, research was undertaken to identify a suitable local or international guideline to govern helicopter noise at night. The proposed use of the helipad is for emergency use. Research into the public consultation exercise for the United States of America Federal Aviation Agency Hearings on [Non-military] Helicopter Noise has indicated that noise from emergency medical helicopter services was exempted from the list of ‘Recommended Noise Reduction Approaches’. There was a wide consensus among stakeholders that emergency helicopter service is a tolerable necessity, although consideration may also be given to imposing some regulation on operations to reduce noise impacts to NSRs.  One example would be to require helicopters to use flight routes that take them as a matter of regulation over the least densely populated areas (paraSection 4.2.11 refers).

4.6.55      Locally there is no standard for helicopter noise at night-time. In accordance with the Civil Aviation (Aircraft Noise) Ordinance (Cap 312), which is the legislative means in Hong Kong to control the helicopter noise arising from the operation of the helipad, administrative means can be used to reduce the noise impact of the helipad operations on the NSRs. However restrictions such as limiting the number of helicopter flights at night time or restrictions on the operating hours of the helipad are not practical as the use concerned is for emergency service, which will be on an as needed basis that cannot be controlled.

4.6.56      Regarding the control of helicopter flightpath, the proposed route displayed Figure 4.3 represents the best arrangement to satisfy operational requirements.  As the helipad is for emergency purposes, and considering that this is a tolerable necessity, it is proposed that construction of the helipad at the proposed location is acceptable. This view is supported not only by the findings of the technical assessment, but also from community feedback from the Value Management exercise [Sub-section 2.2 refers] and the fact that the pre-1998 landing site outside the North Lamma Clinic did not lead to any recordedgistered noise complaints.

4.6.57      The only environmental impact arising from the proposed helipad is the residual noise impact. To totally remove the residual noise impact will involve further relocating the proposed site westwards which will not be acceptable as outlined above. Also, since the residual noise impact has been identified as being of short duration and infrequent occurrence, it will not lead to any long-term serious environmental implications.

4.6.58      In August 2005, with the assistance of GFS, validation noise measurements of the ‘EC155 B1’ and ‘Super Puma AS332 L2’ type helicopters were conducted at representative NSRs as the helicopters simulated manoevring activities on and adjacent to the temporary and proposed permanent helipads. Noise measurements were made at the four NSRs displayed by Figure 4.5, with two of the NSRs having been used in the impact assessment (i.e., M1 (NSR2) and M4 (NSR4)).  The measured and the corrected noise levels for these NSRsresults are presented in Table 4.16Table 4.16Table 4.16Table 4.16Table 4.16Table 4.16Table 4.16Table 4.16 belowfor reference.

 


Table