4     NOISE.. 4-1

4.1    Introduction. 4-1

4.2    Environmental Legislation, Policies, Plans, Standards and Criteria. 4-1

4.3    Description of the Environment 4-2

4.4    Sensitive Receivers. 4-2

4.5    Assessment Methodology. 4-2

4.6    Identification of Environmental Impacts. 4-2

4.7    Prediction and Evaluation of Environmental Impacts. 4-2

4.8    Mitigation of Adverse Environmental Impacts. 4-2

4.9    Evaluation of Residual Impacts. 4-2

4.10  Construction Activities during Restricted Hours. 4-2

4.11  Environmental Monitoring and Audit 4-2

4.12  Conclusion. 4-2

 

 

4                    NOISE

4.1              Introduction

4.1.1          This section presents the potential noise impacts arising from the reclamation works including associated dredging works. It is expected that construction noise impact will arise from the proposed Project as well as the nearby concurrent projects (i.e. other Schedule 2 Designated Projects, Central Reclamation Phase III (CRIII) and Hong Kong Convention and Exhibition Centre Atrium Link Extension (HKCEC ALE). Cumulative daytime construction noise impacts are assessed in this study.  At the time of carrying out this EIA, information on the two potential future railway projects (i.e. SCL and NIL) were not available, therefore the cumulative noise impact arising from these two railway projects has not been assessed in this section. An indicative assessment for dredging and seawall construction works undertaken within restricted hours has also been undertaken.

4.1.2          In view of the project nature, no adverse noise impact during the operation phase would be anticipated.  Thus, this section would only focus on construction noise impact assessment.

4.2              Environmental Legislation, Policies, Plans, Standards and Criteria

General

4.2.1          Noise impacts have been assessed in accordance with the criteria and methodology given in the Technical Memoranda (TMs) under the Noise Control Ordinance (NCO), and Annexes 5 and 13 in the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).

4.2.2          The NCO and EIAO provide the statutory framework for noise control.  Assessment procedures and standards are set out in five TMs listed below:

·              EIAO-TM

·              TM on Noise from Construction Work other than Percussive Piling (GW-TM)

·              TM on Noise from Percussive Piling (PP-TM)

·              TM on Noise from Construction Work in Designated Areas (DA-TM) 

·              TM on Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM)

Construction Noise – General Construction Works

4.2.3          The NCO provides the statutory framework for noise control of construction work, other than percussive piling, using powered mechanical equipment (PME) between the hours of 1900 and 0700 hours or at any time on Sundays and general holiday (that is, restricted hours).  Noise control on construction activities taking place at other times is subject to the Criteria for Evaluating Noise Impact stated in Table 1B of Annex 5 in the EIAO-TM.  The noise limit is Leq (30 minutes) 75 dB(A) at the façades of dwellings and 70 dB(A) at the façade of schools (65 dB(A) during examinations).

4.2.4          Between 1900 and 0700 hours and all day on Sundays and public holidays, activities involving the use of PME for the purpose of carrying out construction work is prohibited unless a construction noise permit (CNP) has been obtained.  A CNP may be granted provided that the Acceptable Noise Level (ANL) for the NSRs can be complied with.  ANLs are assigned depending upon the area sensitive rating (ASR).  The corresponding basic noise levels (BNLs) for evening and night time periods are given in Table 4.1.


Table 4.1      Construction Noise Criteria for Activity other than Percussive Piling

Time Period

Basic Noise Level (BNLs), Leq (30-min) dB(A)

ASR A

ASR B

ASR C

Evening (1900 to 2300 hours) (1)

60

65

70

Night (2300 to 0700 hours)

45

50

55

Notes:   (1)        Includes Sundays and Public Holidays during daytime and evening

4.2.5          Despite any description or assessment made in this EIA Report on construction noise aspects, there is no guarantee that a Construction Noise Permit (CNP) will be issued for the project construction.  The Noise Control Authority will consider a well-justified CNP application, once filed, for construction works within restricted hours as guided by the relevant Technical Memoranda issued under the Noise Control Ordinance.  The Noise Control Authority will take into account  contemporary conditions / situations of adjoining land uses and any previous complaints against construction activities at the site before making his decision in granting a CNP.  Nothing in this EIA Report shall bind the Noise Control Authority in making his decision.  If a CNP is to be issued, the Noise Control Authority shall include in it any condition he thinks fit.  Failure to comply with any such conditions will lead to cancellation of the CNP and prosecution action under the NCO.

4.2.6          For the purpose of assessing the feasibility of carrying out construction works during restricted hours, the noise sensitive receivers in the Study Area are assumed to be ‘ASR B’ in a conservative approach.  The construction noise criteria for the sensitive receivers would be 65 dB(A) in the evening and 50 dB(A) at night.  The Noise Control Authority would decide the Area Sensitivity Rating 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.  The Area Sensitivity Ratings assumed in this EIA Report are for indicative assessment only.  The assessment for construction activities during restricted hours is presented in Section 4.10.

4.2.7          Percussive piling is prohibited between 1900 and 0700 hours on any weekday not being a general holiday and at any time on Sunday or general holiday.  A CNP is required for the carrying out of percussive piling between 0700 and 1900 hours on any day not being a general holiday.  PP-TM sets out the requirements for working and determination of the permitted hours of operations.  ANLs for percussive piling for different types of NSRs are shown in Table 4.2.

Table 4.2      Acceptable Noise Levels for Percussive Piling

NSR Window Type or Means of Ventilation

ANL, Leq (30-min) dB(A)

NSR (or part of NSR) with no windows or other opening

100

NSR with central air conditioning system

90

NSR with windows or other openings but without central air conditioning system

85

Note:      10 dB(A) shall be subtracted from the ANLs shown above for NSRs which are hospitals, medical clinics, educational institutes, courts of law or other NSRs which are considered by the Authority to be particularly sensitive to noise.


4.2.8          In accordance with PP-TM, the permitted hours of operation for carrying out of percussive piling work involving use of diesel, pneumatic and/or steam hammers, subject to the issuance of a CNP, are listed in Table 4.3.

Table 4.3      Permitted Hours of Operation for Percussive Piling

Amount by which Corrected Noise Level (CNL) exceeds Acceptable Noise Level (ANL), CNL-ANL

Permitted hours of operation on any day not being a general holiday

-10 dB(A) < CNL-ANL

Nil

CNL-ANL £ -10 dB(A)

0700 to 1900

4.2.9          Under the TM on Noise from Construction Work in Designated Areas, the use of five types of Specified Powered Mechanical Equipment (SPME) and three types of Prescribed Construction Work (PCW) within a designated area during restricted hours would require a valid CNP.  The SPME includes hand-held breaker, bulldozer, concrete lorry mixer, dump truck and hand-held vibratory poker.  The PCW are:

·              erecting or dismantling of formwork or scaffolding

·              loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material

·              hammering

4.2.10      In general, it should not be presumed that a CNP would be granted for carrying out PCW within a designated area during the restricted hours.  The CNP may be granted for the execution of construction works during restricted hours involving the use of PME and / or SPME if the relevant Acceptable Noise Levels and criteria stipulated in the GW-TM and DA-TM can be met.

4.3              Description of the Environment

4.3.1          The existing land uses in Wan Chai, Causeway Bay and North Point near the proposed Project are commercial, residential and recreational uses. The dominant existing noise source comes from the road traffic on busy Gloucester Road, Victoria Park Road and Island Eastern Corridor. 

4.3.2          Since the works programme of the Project will overlap with other Schedule 2 DPs, CRIII and HKCEC ALE projects in some periods, cumulative construction noise impacts would be expected at some noise sensitive receivers.

4.4              Sensitive Receivers

4.4.1          In order to evaluate the construction noise impacts from the Project, representative existing noise sensitive receivers (NSRs) within 300m from the boundary of the Project (Study Area) are identified for assessment.  Only the first layer of NSRs has been identified for assessment because it would provide acoustic shielding to those receivers at further distance behind. According to the normal practices adopted for similar land uses in Hong Kong (e.g. existing HKAPA, Visitor Centre of Hong Kong Wetland Park), the commercial buildings, HKAPA Extension and the Harbour Education Centre would be provided with central air-conditioning system and they do not rely on openable window for ventilation. Thus, no adverse noise impact upon these premises would be expected and, therefore they are not selected for noise impact assessment. In the absence of the programme of proposed re-provisioned Tin Hau Temple, construction noise impact assessment would only focus on existing NSRs. Table 4.4 and Figure 4.7 show the representative NSRs selected for construction noise impact assessment. The photographs of the representative NSRs are shown in Appendix 4.4. These representative assessment points for quantitative noise assessment have been agreed with the Environmental Protection Department (see Appendix 15.1).

Table 4.4      Representative Existing  Noise Sensitive Receivers

NSR

Section

Location

Use

Ground elevation (mPD)

No. of Floors

N1

Wanchai

HKAPA (Open Arena)

Performing Arts Centre

5.0

G/F

N2

Wanchai

Causeway Centre

Residential

4.0

42

N3

Wanchai

Gloucester Road 169-170

Residential

3.7

12

N6

Causeway Bay

Elizabeth House

Residential

3.7

21

N8

Causeway Bay

Marco Polo Mansion

Residential

4.3

15

N13

Tin Hau

Belle House

Residential

3.6

24

N15

Tin Hau

Staff Quarters of FEHD

Residential

4.0

4

N17

Tin Hau

Harbour Heights

Residential

4.3

44

N18

North Point

City Garden, Block 10

Residential

4.0

27

N20

North Point

Hong Kong Baptist Church Henrietta Secondary School

Educational Institution

4.0

6

 

4.5              Assessment Methodology

Construction Noise during Unrestricted Hours

4.5.1          The Schedule 3 Designated Project is scheduled to be commenced in early 2009 and to be completed in 2016.  According to the construction programme, there are eight major construction tasks (as shown in Appendix 2.5).  Some individual tasks have different stages.  Table 4.5 summarises the different tasks and phasing. All construction tasks are planned to be carried out during unrestricted hours. Figure 3.4 shows the locations of work sites. 


Table 4.5      Summary of Construction Tasks and Stages

Item

Tasks and Stages

Construction Period

Main Construction Elements

1           Causeway Bay Reclamation

1.1

Temporary Relocation Causeway Bay Typhoon Shelter(CBTS)

January 2009 to February 2016

Temporary Breakwater

Relocation Mooring to Temporary CBTS

Relocation Mooring back to CBTS

1.2

CBTS Temporary Reclamation Stage 1

August 2009 to May 2012

Dredging, temp seawalls and filling (TCBR1)

CWB Tunnel (TCBR1)

CWB Tunnel (Cross Harbour Tunnel)(CHT)

1.3

CBTS Temporary Reclamation Stage 2

November 2009 to May 2012

Dredging, temp seawalls and filling (TCBR2)

CWB Tunnel (TCBR2)

1.4

CBTS Temporary Reclamation Stage 3

January 2011 to April 2014

Dredging, temp seawalls and filling (TCBR3)

CWB Tunnel (TCBR3)

1.5

CBTS Temporary Reclamation Stage 4

May 2012 to November 2015

Dredging, temp seawalls and filling (TCBR4)

CWB Tunnel (TCBR4)

1.6

Temp Diversion of Cooling Water System

October 2010 to January 2016

 

1.7

Promenade along CBTS

November 2015 to March 2016

 

1.9

Slip Road & Victoria Park Reprovisioning

August 2013 to March  2015

Victoria Park Road Traffic Division

Slip Road 8 &Tunnel

Transplant Trees in Victoria Park

At-grade Road, Landscaped deck

Reinstate Landscape work in VP 

2         Ex-PCWA Temporary Reclamation

2.1

Temporary Reclamation PCWA Stage 1

February 2009 to May 2012

Dredging, Filing and Seawall (PCWAE)

CWB Tunnel (PCWAE)

2.2

Temporary Reclamation PCWA Stage 2

March 2012 to May 2015

Dredging, Filing and Seawall (PCWAW)

CWB Tunnel (PCWAW)

3          Wan Chai Reclamation

3.1

Wan Chai Reclamation

Stage 1

January 2009 to February 2011

Dredging, Seawalls and Filling

Drainage Culverts

Cooling Water Syetem

CWB Tunnel(WCR1)

3.2

Wan Chai Reclamation

Stage 2

January 2011 to May 2013

Dredging, Seawalls and Filling

CWB Tunnel

Promenade

3.3

Wan Chai Reclamation

Stage 3

April 2011 to March 2015

Dredging, Seawalls and Filling

CWB Tunnel

Promenade

3.4

Wan Chai Reclamation

Stage 4

October 2012 to March 2015

Dredging, Seawalls and Filling

Drainage Culverts

CWB Tunnel

Promenade

3.6

Ferry Pier Reprovisioning

February 2009 to May 2011

Temporary Ferry Piers

New Ferry Piers

3.7

Helipad Reprovisioning

January  2009 to June 2010

Reprovisioning at HKCEC

3.8

Sewage Outfall

October 2009 to April  2011

Marine Section – Submarine Pipelines

Land Section – New Pipeline

3.9

WSD’s Salt Water Pumping Station

February 2009 to October 2010

Construct New Pumping Station

3.10

Roads

October 2014 to September 2015

Road P2

4           HKCEC Reclamation

4.1

HKCEC Reclamation Stage 1 (Water Channel)

January 2009 to April  2016

Dredging, Seawalls and Filling

Cooling Water Systems

CWB Tunnel

4.2

HKCEC Reclamation Stage 2

January 2009 to March 2014

Dredging, Seawalls and Filling

Drainage Culverts

CWB Tunnel

4.3

MTR Tunnel Crossing

October 2010 to February 2012

Piling for Tunnel Units and Deck

Tunnel and Deck Construction

4.4

HKCEC Reclamation Stage 3

March 2011 to October 2013

Dredging, Seawalls and Filling

Drainage CulvertsCWB Tunnel

4.5

Roads

March 2014 to November 2015

Road P2

 

5           Cross Harbour Watermains

5.1

Submarine Pipeline

January 2009 to September 2010

Lay New Submarine Pipeline

5.2

Lands Sections

September 2009 to May 2010

Lay Land Piplines HKCEC

 

6.0        North Point Reclamation

6.1

North Point Reclamation Stage 1

January 2009 to October 2010

Dredging, Seawalls and Filling

CWB Tunnel (NPR1)

6.2

North Point Reclamation Stage 2

April 2009 to November 2012

Dredging, Seawalls and Filling (NPR2E, NPR2W)

CWB Tunnel (NPR2W)

6.3

Promenade

August 2016 to December 2016

Promenade (NP) Final

7.0       Construction of Island Eastern Corridor Link (IECL)

7.2

IEC Connection Work

October 2010 to May 2016

IEC East Bound (E/B) (HFS to Mainline)

IEC E/B Traffic Diversion

Reconstruction IEC West Bound(W/B)

IEC W/B Traffic Diversion

Mainline Connection to IEC

7.3

East Portal and IEC Connection

May 2015 to August 2016

Portal Construction

Traffic Diversion IEC E/B

10

Tunnel Building and Installation

November 2011 to May 2016

 

10.1

East Ventilation Building

November 2012 to September 2013

Superstructure of the Building

E&M Work

10.2

Administration Building

February 2015 to November 2015

Substructure of the Building

Superstructure of the Building

E&M Work

10.3

Central Ventilation Building

January 2014 to January 2015

Substructure of the Building

Superstructure of the Building

E&M Work

 

4.5.2          The maximised use of public fill is proposed in the reclamation and the construction noise assessment is based on this construction programme and associated plant use.  In considering the alternative greater use of sand fill, the public fill scenarios will require more noise generating plant use over longer periods of time and, in overall terms, the assessment that has been undertaken can therefore be considered to represent the worst case reclamation method.

4.5.3          The construction noise assessment has been carried out on a monthly basis from the commencement of the Project. The construction tasks of the Project taking place concurrently within 300 m of a given NSR are considered to contribute to the cumulative impact at that NSR.  Noise sources from the areas greater than this distance have been excluded from the assessment.

4.5.4          In accordance with the EIAO, the methodology outlined in the GW-TM has been used for the assessment of construction noise (excluding percussive piling).  Sound Power Levels (SWLs) of the equipment were taken from Table 3 of this TM.  Where no SWL was supplied in the GW-TM, reference was made to BS 5228, previous similar studies or from measurements taken at other sites in Hong Kong. Schedule of powered mechanical equipment (PME) for the different construction tasks during normal daytime working hours is presented in Appendix 4.5.

4.5.5          In view of the anticipated adverse noise impact at the NSRs in the vicinity of Causeway Bay reclamation and North Point reclamation areas due to the limited buffer distance, appropriate on-time percentage for some items of PME, including poker vibrator, crane, excavator and tug boat, dump truck and backhoe were reasonably assumed as presented in Appendix 4.5. The Civil Engineering and Development Department (CEDD) and the Highways Department (HyD) have confirmed that it is practicable and feasible in the context of the construction programme (see Appendix 15.1).    

4.5.6          It was assumed that all PME items required for a particular construction activity would be located at the notional or probable source position of the segment where such activity is to be performed. The assessment is based on the cumulative SWL of PME likely to be used for each location, taking into account the construction period in the vicinity of the receiver location.  To predict the noise level, PME was divided into groups required for each discrete construction task.  The objective was to identify the worst case scenario representing those items of PME that would be in use concurrently at any given time.  The sound pressure level of each construction task was calculated, depending on the number of plant and distance from receivers.  The noise levels at NSRs were then predicted by adding up the SWLs of all concurrent construction tasks.


4.5.7          A positive 3 dB(A) façade correction was added to the predicted noise levels in order to account for the façade effect at each NSR.  The boundary walls around HKAPA Open Arena are assumed as noise barriers and a 5 dB(A) reduction of the predicted noise levels at receiver N1 is expected due to the shielding effect.

4.5.8          The CRIII project has already commenced and is scheduled to be completed in September 2012.  Besides, the Hong Kong Convention and Exhibition Centre, Atrium Link Extension (HKCEC ALE) project is scheduled to commence in May 2006 and to be completed in March 2009, according to the EIA Report for HKCEC ALE (March 2006).  Therefore, some construction tasks of the CRIII and HKCEC ALE projects will be carried out within the same construction period of the Project.  The following construction activities of these projects will overlap with the Project:

l             CRIII Project

l             CWB under CRIII main contract (December 2008 – March 2012)

l             Drainage Culverts (October 2008 – September 2012)

l             Roadworks (October 2008 – September 2012)

l             HKCEC ALE Project

l             Remove marine piles for working platform (October 2008 – November 2008)

l             Demolish temporary footbridge (December 2008 – February 2009)

l             Remove marine piles for temporary footbridge (January 2009 – March 2009)

4.5.9          The PMEs for CRIII project with mitigation measures, as shown in Appendix 4.6, were made with reference to the EIA Report for CRIII.  Besides, in accordance with the EIA Report for HKCEC ALE, the maximum SWL of the construction activities throughout the construction period would be estimated to be about 127 dB(A). The noise data from these two studies was adopted to calculate the cumulative construction noise impact in this EIA study.

Construction Noise During Restricted Hours

4.5.10      The construction programme for the Project takes into account the likelihood that the contractor will, if permitted, undertake dredging and seawall construction works over a 16-hour working day (0700 to 2300 hours) at the area of PCWA, Wan Chai Reclamation and HKCEC Reclamation. This is in order to maintain his required work rates to meet the tight programme with some allowance for plant downtime, variability in fill supply rates, etc. The longer working hours will also ensure that allowance can be made to cater for possible changes in dredging and filling rates due to deterioration of water quality. 

4.5.11      The following key activities may require construction noise permits for night work.

(i)           Marine-based construction activities:

(ii)         dredging of reclamation areas and seawalls

(iii)        seawall trench filling

(iv)       seawall construction

(v)         filling behind seawalls


4.5.12      According to GW-TM, for any construction works planned during the restricted hours, the Contractor will be required to apply for a CNP from the Noise Control Authority and has the responsibility to ensure compliance with the NCO and relevant TM.  Therefore, an indicative noise assessment in this EIA is for the evaluation of whether construction works in restricted hours are feasible or not in the context of programming construction work only. Detailed discussion is presented in Section 4.10.

Level of Uncertainty

4.5.13      The predictions of construction noise impact were based on the methodologies described in the GW-TM under the NCO.  The methodology which had previously been applied in other EIA studies is generally accepted for use in assessing construction noise impacts against EIAO-TM noise criteria. 

4.5.14      There would be some limitations such as the accuracy of the predictive base data for future conditions e.g. plant inventory for the proposed construction works. Uncertainties in the assessment of impacts have been considered when drawing conclusions from the assessment. 

4.5.15      In carrying out the assessment, realistic worst case assumptions have been made in order to provide a conservative assessment of noise impacts.  The construction noise impact was assessed based on conservative estimates for the types of plant and methods of working. 

4.6              Identification of Environmental Impacts

Construction Noise

4.6.1          Schedule 2 DP3 is scheduled to be commenced in January 2009 and to be completed in Feburary 2013. The construction tasks under DP3 include:

l             reclamation works including associated dredging works at HKCEC1, HKCEC2 and HKCEC3

l             reclamation works including associated dredging works at WCR1, WCR2 and WCR3

l             reclamation works including associated dredging works at TPCWAE and TPCWAW

l             reclamation works including associated dredging works at CBTS

l             reclamation works including associated dredging works at TCBR1E, TCBR2, TCBR3 and TCBR4

l             reclamation works including associated dredging works at NPR1 and NPR2

4.6.2          The construction tasks of this DP3 and other projects taking place concurrently within 300m of a given NSR are considered to contribute to the cumulative impact at that NSR.  Noise sources from the areas greater than this distance have been excluded from the assessment. The concurrent projects considered in the cumulative construction noise assessment for DP3 are as follows:

l             DP1 – Central-Wanchai Bypass (CWB) including its road tunnel and slip roads

l             DP5 - Wan Chai East Sewage Outfall

l             Central Reclamation Phase III (CRIII)

l             Hong Kong Convention and Exhibition Centre, Atrium Link Extension (HKCEC ALE)

 


4.7              Prediction and Evaluation of Environmental Impacts

Construction Noise

4.7.1          For normal daytime working hours, exceedences of the construction noise criteria (Leq (30 minutes) 75 dB(A) for residential uses and 70 dB(A) for educational institutions (65 dB(A) during examinations)) are predicted at representative NSRs in the absence of mitigation measures.  Details of construction noise calculations and results are presented in Appendix 4.7.  Results show that the predicted noise levels related to the concurrent construction works of the Project, other Schedule 2 DPs, CRIII and HKCEC ALE projects are in the range of 61 to 86 dB(A).  A summary of the unmitigated construction noise levels of the representative NSRs during normal daytime working hours within the construction period of the Project is listed in Table 4.6. Noise mitigation measures would therefore be required to reduce noise levels to the stipulated standard.

Table 4.6      Summary of Unmitigated Construction Noise Levels at Representative NSRs During Normal Daytime Working Hours

Representative NSRs

Predicted Unmitigated Construction Noise Levels during Normal Daytime Working Hour (Leq (30-min) dB(A))

N1

69 - 73

N2

67 - 81

N3

62 – 76

N6

68 – 72

N8

65 – 82

N13

61 - 79

N15

66 - 85

N17

65 - 86

N18

62 - 78

N20 #

67 - 71

Note:    #          For normal daytime working hours, the noise criteria are 70 dB(A) and 65 dB(A) for normal teaching periods and examination periods, respectively.

 

4.8              Mitigation of Adverse Environmental Impacts

Construction Noise

4.8.1          In order to reduce the excessive noise impacts at the affected NSRs during normal daytime working hours, mitigation measures such as adopting quiet powered mechanical equipment are recommended.  The above mitigation measures have been vetted and confirmed by the CEDD and HyD as being practicable in completing the works within scheduled timeframe. The Contractor may be able to obtain particular models of plant that are quieter than the PMEs given in GW-TM. It is considered too restrictive to specify that a Contractor has to use specific items of plant for the construction operations. It is practical to specify the total SWL of all plant to be used on site so that the Contractor is allowed some flexibility to select plant to suit his needs. 

4.8.2          In this assessment, the recommended quiet PME are taken from the BS 5228: Part 1: 1997 and the website of EPD, and the PME are known to be available in Hong Kong. The quiet PME adopted for the CRIII construction tasks are in accordance with CRIII EIA Report.


4.8.3          The lists of quiet PME adopted in the construction tasks of the Project during normal daytime working hours are shown in Appendix 4.13. For the following construction tasks of the Project, it is considered necessary to adopt quiet PME:

l             Filling behind seawall

l             Seawall construction

 

4.8.4          The mitigation measures for the items of PME in each construction task have been shown in Appendix 4.13.

4.8.5          As shown in Appendix 4.14, with the use of quiet equipment for the Project as well as noise mitigation measures for other Schedule 2 DPs, the overall noise levels at NSRs would be reduced by 2 to 14 dB(A), depending on the type of construction activities. With the exception of NSR N20 during examination periods, the predicted cumulative construction noise levels at other NSRs selected for construction noise impact assessment would comply with the EIAO-TM construction noise criteria. For N20 (i.e. Hong Kong Baptist Church Henrietta Secondary School), the predicted noise level would exceed the noise standard of 65 dB(A) by 3 dB(A) during examination periods for a total of 8 weeks in 2009.

4.8.6          A summary for mitigated noise levels during normal daytime working hours at representative NSRs is presented in Table 4.7.

Table 4.7      Summary of Mitigated Construction Noise Levels at Representative NSRs during Normal Daytime Working Hours

Representative NSRs

Predicted Mitigated Construction Noise Levels during Normal Daytime Working Hour, (Leq (30-min) dB(A))

N1

68 - 70

N2

63 – 73

N3

60 - 66

N6

63 - 68

N8

58 – 68

N13

5970 (Group 1 PME for DP1)

N13

5970 (Group 2 PME for DP1)

N15

6474

N17

60 - 74 (Group 1 PME for DP1)

N17

60 - 74 (Group 2 PME for DP1)

N18

57 - 74 (Group 1 PME for DP1)

N18

57 - 74 (Group 2 PME for DP1)

N20 #

60 - 68 (Group 1 PME for DP1)

N20 #

60 - 68 (Group 2 PME for DP1)

Note:    #          For normal daytime working hours, the noise criteria are 70 dB(A) and 65 dB(A) for normal teaching periods and examination periods, respectively.

 


4.9              Evaluation of Residual Impacts

Construction Noise

4.9.1          With the implementation of the above-mentioned mitigation measures, the construction noise levels at the NSRs selected for construction noise impact assessment except N20 during examination periods are predicted to comply with the noise standards stipulated in the EIAO-TM. Residual impacts at this affected NSR are summarised in Table 4.8.

4.9.2          The on-site survey has revealed that NSR N20 (Hong Kong Baptist Church Henrietta Secondary School) has already been noise insulated with air-conditioners. With the provision of air-conditioners, it is considered that the noise impact would be minimised by keeping the windows closed during the construction activities. Notwithstanding this, due to a limited buffer distance and a more stringent noise criterion of 65 dB(A), it is recommended that particularly noisy construction activities, especially those associated with the demolition of the IEC Structures, should be scheduled to avoid examination periods as far as practicable.

Table 4.8      Construction Noise Residual Impacts

NSR

Exceedance of the EIAO-TM Criterion of 65 dB(A) for Examination Period

Construction Activity Causing Exceedance

Approximate duration of Exceedance

N20 (Examination Period)

3
(
May - June 2009)

Dredging

 

8 weeks #
(
May - June 2009)

Notes:

#    Public examination is assumed to be held in March, April and May, while school examination is assumed  to be held in December and June of each year.

 

4.9.3          In addition to the above-mentioned mitigation measures, the good site practices listed below shall be adopted by all the Contractors to further ameliorate the noise impacts.  Although the noise mitigating effects are not easily quantifiable and the benefits may vary with the site conditions and operating conditions, good site practices are easy to implement and do not impact upon the works schedule.

l             Only well-maintained plant shall be operated on-site and plant shall be serviced regularly during the construction program.

l             Silencers or mufflers on construction equipment shall be utilised and shall be properly maintained during the construction program.

l             Mobile plant, if any, shall be sited as far away from NSRs as possible.

l             Machines and plant (such as trucks) that may be in intermittent use shall be shut down between works periods or shall be throttled down to a minimum.

l             Plant known to emit noise strongly in one direction shall, wherever possible, be orientated so that the noise is directed away from the nearby NSRs.

l             Material stockpiles and other structures shall be effectively utilised, wherever practicable, in screening noise from on-site construction activities.

4.10          Construction Activities during Restricted Hours

4.10.1      As mentioned in Section 4.5.10 and 4.5.11, marine works may be undertaken over a 16-hour working day (0700 to 2300).  These activities will be under the control of the NCO and the contractors are required to apply for a CNP from the Noise Control Authority before works commence.  An indicative assessment has been undertaken to determine the impacts.  As discussed in Section 4.2.6, the construction criterion of 65 dB(A) in the evening was adopted in this assessment.

4.10.2      The PMEs for construction tasks during restricted hours and assessment results are presented in Appendices 4.19 and 4.20, respectively. On-time percentage for tug boat and crane has been reasonably assumed in this indicative assessment. As marine-based construction activities to be carried out during restricted hours would be confined to the area of PCWA, Wan Chai Reclamation and HKCEC Reclamation, therefore only NSRs N1 to N3 and N6 (i.e. within 300m of these reclamation sites) were selected for this assessment. A summary of unmitigated noise levels at these representative NSRs is presented in Table 4.9.

4.10.3      The lists of quiet PME adopted in the construction tasks of the Project during restricted hours are shown in Appendix 4.21. The following construction tasks of the Project would need to adopt quiet PME:

l             Dredging, seawalls construction, rockfill for seawall foundations, filling behind seawall in the areas of WCR1, WCR2, WCR3, WCR4, HKCEC1, HKCEC2 and HKCEC3 East and West.

Table 4.9      Summary of Unmitigated Construction Noise Levels at Representative NSRs During Restricted Hours

Representative NSRs

Predicted Unmitigated Construction Noise Levels during Restricted Hour  (1900 to 2300 on weekday), (Leq (5-min) dB(A))

N1

57 – 66

N2

63 – 71

N3

61 – 64

N6

64 – 68

4.10.4      For restricted hours construction works, movable noise barriers would be provided for mobile PME, such as excavator and poker vibrator, 5 dB(A) noise screening reduction was assumed in the assessment. A 10 dB(A) noise screening reduction was assumed for stationary PME such as air compressor (see Appendix 4.20).

4.10.5      Predicted noise levels after mitigation at representative NSRs are shown in Appendix 4.22. A summary of mitigated noise levels at representative NSRs is presented in Table 4.10.

Table 4.10    Summary of Mitigated Construction Noise Levels at Representative NSRs During Restricted Hours

Representative NSRs

Predicted Mitigated Construction Noise Levels during Restricted Hour  (1900 to 2300 on weekday), (Leq (5-min) dB(A))

N1

53 – 62

N2

59 – 67

N3

57 – 62

N6

60 – 65

 

4.10.6      With the adoption of the recommended mitigation measures, the predicted noise levels at NSRs N1 (HKAPA Open Arena), N3 (Gloucester Road 169-170) and N6 (Elizabeth House) would comply with the construction noise criterion of 65 dB(A) during restricted hours. For N2 (Causeway Centre), there would be 2 dB(A) exceedance of noise limit due to dredging works based on the current information. The Applicant (i.e. the Contractor) shall implement all practicable noise mitigation measures to mitigate the noise impact. In applying for a Construction Noise Permit, the Contractor shall be required to demonstrate to the satisfaction of the Noise Control Authority the Sound Power Level of the quiet PMEs and/or the noise reduction effect of other mitigation measures to be adopted.  Otherwise, values in the GW-TM will be used in assessing the application.

4.10.7      The above assessment only demonstrates that the construction works in restricted hours would be feasible in the context of programming construction work. If the Contractor considers that there is a need to carry out construction works during restricted hours, a Construction Noise Permit shall be obtained from the Noise Control Authority prior to commencement of such works.  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 application based on the contemporary situations / conditions.  It should be noted that the situations / conditions around the sites may change from time to time.  The Authority may make correction for multiple permit situations if in the opinion of the Authority the NSR will be materially affected by noise from construction work associated with more than one CNP, and the Authority may make such correction to the relevant noise level as it considers appropriate having regard to standard acoustical principles and practices. The Area Sensitivity Ratings assumed in this EIA Report are for indicative assessment only.

4.11          Environmental Monitoring and Audit

Construction Noise

4.11.1      An EM&A programme is recommended to be established according to the predicted occurrence of noisy activities. All the recommended mitigation measures for daytime normal working activities should be incorporated into the EM&A programme for implementation during construction.  Details of the programme are provided in the stand-alone EM&A Manual.

4.12          Conclusion

Construction Phase

4.12.1      This assessment has predicted the construction noise impacts of the Project during normal daytime working hours, taking into account other concurrent projects including other Schedule 2 DPs, CRIII and HKCEC ALE projects. The predicted unmitigated noise levels would range from 61 to 86 dB(A) at the representative NSRs. With the use of quiet PME for the Project,  implementation of the noise mitigation measures for other Schedule 2 DPs and CRIII project, the predicted cumulative noise levels at the NSRs selected for construction noise impact assessment except N20 during examination periods would comply with the construction noise standard. For N20 (i.e. Hong Kong Baptist Church Henrietta Secondary School), the predicted noise level would exceed the noise standard of 65 dB(A) by 3 dB(A) during examination periods for a total of 8 weeks in 2009. However, the school has been noise insulated with air conditioners and, by keeping the windows closed during construction activities, noise impacts at the indoor environment can be avoided. Notwithstanding this, it is recommended that the particularly noisy construction activities be scheduled to avoid examination period as far as practicable.


4.12.2      An indicative assessment has been undertaken for possible construction activities during restricted hours (1900 to 2300) associated with the reclamation works of the Project. With the adoption of quite PME and movable noise barriers, the predicted noise levels at the NSRs selected for construction noise impact assessment except NSR N2 would comply with construction noise criterion of 65 dB(A). It should be noted that the results of the construction noise impact assessment for restricted hours (1900 to 2300) are for indicative purposes, the Noise Control Authority will process any CNP application based on the NCO and the relevant technical memoranda in addition to considering the contemporary situations / conditions.

4.12.3      A construction noise EM&A programme is recommended to check the compliance of the noise criteria during normal daytime working hours.