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
4.1.1
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.
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
|
|
Basic Noise
Level (BNLs), Leq (30-min) dB(A)
|
|
|
ASR B
|
ASR C
|
|
Evening (1900 to 2300 hours) (1)
|
60
|
65
|
70
|
|
|
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
|
|
|
|
|
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
|
|
|
|
|
|
|
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.
4.4.1
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
|
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
|
59 – 70
(Group 1 PME for DP1)
|
|
N13
|
59 – 70
(Group 2 PME for DP1)
|
|
N15
|
64 – 74
|
|
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.
4.10.1
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.