4.1
Introduction
4.1.1
This
section presents the potential noise impacts arising from the proposed CWB
& IECL during construction and operational phases. The construction noise
levels associated with the proposed Project have been predicted based on the estimate
of the construction plants used and the phasing of the construction programme,
in addition to the construction noise levels arising from the concurrent
projects including Central Reclamation Phase III (CRIII) and Wan Chai
Development Phase II (WDII) and the Causeway Bay Flyover. During operational
phase, noise impact from road traffic and the ventilation shafts of the
proposed ventilation buildings are anticipated. The predicted noise levels
during construction and operational phases have been assessed against the
EIAO-TM noise criteria. Appropriate
mitigation measures have been recommended where adverse impacts are predicted.
4.2
Environmental
Legislation, Policies, Plans, Standards and Criteria
4.2.1
Noise
impacts have been assessed in accordance with the criteria and methodology
given in the Technical Memoranda (TM) made under the Noise Control Ordinance
(NCO) and the Technical Memorandum on Environmental Impact Assessment Process
(EIAO-TM).
4.2.2
The
Noise Control Ordinance (NCO) provides the statutory framework for noise
control. Assessment procedures and
standards are set out in the following five Technical Memoranda:
· 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
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 or at any time on Sundays and a 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 75 dB(A) Leq
(30 minutes) at the facades of dwellings and 70 dB(A) Leq (30
minutes) at the facades 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 powered mechanical equipment (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 noise sensitive
receivers (NSRs) can be complied with.
ANLs are assigned depending upon the Area Sensitivity Ratings (ASRs).
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) |
||
|
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 its
decision. If a CNP is to be issued, the
Noise Control Authority shall include in the permit any condition it 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
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 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 type 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, dB(A) |
|
(i) NSR (or part of NSR) with no windows or other opening |
100 |
|
(ii) NSR with central air conditioning system |
90 |
|
(iii) 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.
4.2.7
Effective
from 1 October 1999, the use of diesel, pneumatic and / or steam hammers are
not allowed to be used in Hong Kong.
The permitted hours of operation for carrying out of percussive piling
work 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 |
0800 to 0900 AND 1230 to 1330 AND 1700 to 1800 |
|
0 dB(A) < CNL-ANL £ 10 dB(A) |
0800 to 0930 AND 1200 to 1400 AND 1630 to 1800 |
|
CNL-ANL £ 0
dB(A) |
0700 to 1900 |
4.2.8
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 to obtain 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; and
· hammering.
4.2.9
In
general, the CNP would not be normally granted for carrying out PCW within a
designated area 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 could not be met.
4.2.10 Table 4.1 of Hong Kong Planning
Standard Guidelines (HKPSG) and Annex 5 of EIAO-TM: Criteria for Evaluating Noise Impact are adopted. The criteria for road traffic noise at various
NSRs are as follows:
· 70 dB(A) at the facades of dwellings, hotels, offices;
· 65 dB(A) at the facades of schools, places of public Worship, courts of law, the place where unaided voice communication is required; and
· 55 dB(A) at the facades of hospital.
4.2.11 Based on the above criteria and aiming at traffic noise impacts at the NSRs not worse than before, the predicted noise levels arising from ‘New’ roads (as defined in section 4.2.13) should be less than 70 dB(A) for dwellings and 65 dB(A) for educational institutions, and the contribution to the increase in the predicted overall noise level from the ‘new’ road should be not greater than 1.0 dB(A).
4.2.12 If any facades of NSRs are still
exposed to predicted noise levels exceeding the relevant noise criteria after
the implementation of all direct mitigation measures, provision of indirect
technical remedies in the form of acoustic insulation and air conditioning
should be considered under the ExCo directive “Equitable Redress for Persons
Exposed to Increased Noise Resulting from the use of New Roads”. Eligibility for indirect technical remedies
will be tested against the following three criteria:
· The predicted overall noise level from the ‘new’ road, together with other traffic noise in the vicinity must be above 70 dB(A) for residential dwellings and 65 dB(A) for educational institutions.
· The predicted overall noise level is at least 1.0 dB(A) more than the prevailing traffic noise level.
· The contribution to the increase in the predicted overall noise level from the ‘new’ road must be at least 1.0 dB(A).
4.2.13 For the purpose of the traffic noise
assessment in this Study, the roads within the 300 m of the Study Area are
included in the assessment. All roads
are described as either one of the following:
· ‘Existing’ Roads are the roads that are unchanged or subject to minor changes by the Project and the proposed roads from CRIII Project.
· ‘New’ Roads are the roads that are completely new or existing road section undergoes major modification that will result in 25% increase in lanes or substantial changes in alignment or characters of the existing road due to the proposed Project.
· ‘New (Others)’ Roads are all new roads or existing road section undergoes major modification which will result in 25% increase in lanes or substantial changes in alignment of the existing road due to the other projects such as CRIII and WDII.
4.2.14 The ‘new’ roads adopted for the CWB
and IECL in the assessment are shown in Figures A4.1 to A4.3 in Appendix 4.3.
4.2.15 Fixed noise source such as
ventilation shaft noise is controlled by the NCO and IND-TM. The appropriate
Acceptable Noise Levels (ANL) generated by fixed plant at neighbouring NSRs are
provided in IND-TM. The representative
NSRs in the vicinity of ventilation buildings are located in urban area and are
near busy roads such as Gloucester Road with an average daily traffic flow in
excess of 30,000 and the low traffic flow rate would be more than 300 vehicles
per hour. Most of the representative
NSRs would be directly or indirectly affected by traffic noise. Therefore, the Area Sensitivity Rating (ASR)
for these NSRs has been assumed as ‘C’.
However, some NSRs are facing north, and Gloucester Road is at the back
of the receivers. The ASR for these
NSRs has been assumed as ‘B’. The ANLs
for an ASR of ‘B’ and ‘C’ under the IND-TM are shown in Table 4.4. Since the EIAO-TM recommends that noise
standard for fixed noise source is 5 dB(A) below the appropriate ANL, the noise
criteria of 60 / 65 dB(A) (daytime and evening) and 50 / 55 dB(A) (night-time)
will be adopted for assessment.
4.2.16 In any event, the ASR assumed in
this EIA Report is for indicative assessment only given that fans and damper
arrangement at each ventilation building may be refined in detailed
design. It should be noted that the fixed
noise sources are controlled under section 13 of the NCO. At the time of investigation, the Noise
Control Authority shall determine noise impact from concerned fixed noise
sources on the basis of prevailing legislation and practices being in force, and
taking account of contemporary conditions / situations of adjoining land
uses. Nothing in this EIA Report shall
bind the Noise Control Authority in the context of law enforcement against all
the fixed noise sources being assessed.
Table 4.4 Acceptable Noise
Level for Fixed Plant Noise
|
NCO criteria |
EIAO-TM |
|||
|
ASR ‘B’ |
ASR ‘C’ |
ASR ‘B’ |
ASR ‘C’ |
|
|
Daytime and Evening (0700 - 2300 hours) |
65 |
70 |
60 |
65 |
|
Night-time (2300 - 0700 hours) |
55 |
60 |
50 |
55 |
4.3 Description of the Environment
4.3.1
The
major existing noise source in the Study Area is the traffic noise from busy
Connaught Road Central,
4.3.2
As the
existing road traffic flow is high, it is expected that most of the facades
along the above-mentioned roads would exceed the EIAO-TM noise criteria.
4.3.3
During
construction phase of the Project, it is expected that construction activities
would pose adverse noise impacts on the nearby sensitive receivers,
particularly near the IECL section. Taking into account the WDII and CRIII
projects, cumulative construction noise impact is anticipated.
4.3.4
When
the CWB & IECL is in operation, it is expected that the road traffic will
constitute a higher background noise than that at present.
4.4.1
In
accordance with Section 3 of Annex 13 of EIAO-TM, the existing noise sensitive
receivers (NSRs) within 300 m of the Study Area have been identified and are
summarised in Table 4.5.
Table 4.5 Summary of Identified
Existing Noise Sensitive Receivers
|
Area |
Location |
Use |
|
Sheung Wan |
Korea Centre |
Residential |
|
Central |
City Hall |
Performing Arts Centre |
|
PLA Headquarters |
Others (Military) |
|
|
Wan Chai |
The Hong Kong Academy for Performing Arts (HKAPA)
(open arena) |
Performing Arts Centre |
|
|
Art Centre |
Performing Arts Centre |
|
|
Hong Kong Convention & Exhibition Centre
(HKCEC) Extension |
Convention and Exhibition |
|
|
Causeway Centre |
Residential |
|
|
City Mansion |
Residential |
|
|
170 Gloucester Road |
Residential |
|
|
Kam Kwok Building, 210 Gloucester Road |
Residential |
|
|
Kei Wa Building |
Residential |
|
|
Hyde Centre |
Residential |
|
Wan Chai |
Sang Woo Building |
Residential |
|
|
Elizabeth House |
Residential |
|
|
Hoi Kung Court |
Residential |
|
|
Hoi To Court |
Residential |
|
|
Hoi Deen Court |
Residential |
|
|
Riviera Mansion |
Residential |
|
|
Prospect Mansion |
Residential |
|
|
Miami Mansion |
Residential |
|
|
Highland Mansion |
Residential |
|
|
Marco Polo Mansion |
Residential |
|
|
Victoria Park Mansion |
Residential |
|
|
Chesterfield Mansion |
Residential |
|
|
Greenfield Mansion |
Residential |
|
Tin Hau |
|
Residential |
|
|
|
Residential |
|
|
Mayson Garden |
Residential |
|
|
Gorden House |
Residential |
|
|
Belle House |
Residential |
|
|
Hoi Tao Building |
Residential |
|
|
Deport of Food and Environment Hygiene Department
(FEHD) |
Government quarters and office |
|
|
Victoria Centre |
Residential |
|
|
Harbour Heights Tower |
Residential |
4.4.2
For
the purpose of noise impact assessment, representative existing and planning
NSRs within 300 m from the Study Area are identified. Some representative NSRs along the Project alignment have been
selected in accordance with the criteria in the EIAO-TM to evaluate the
construction noise impacts. While Table
4.6 summarises the selected NSRs for construction noise impact assessment,
Table 4.7 summarises the representative NSRs for traffic noise impact
assessment. Their locations are shown
in Figure 4.1.
Table 4.6 Summary
of Representative Existing Noise Sensitive Receivers for Construction Noise
Impact Assessment
|
NSR |
Section |
Location |
Use |
Ground Elevation (mPD) |
No. of Floors |
|
N1 |
Sheung Wan |
Korea Centre |
Residential |
3.8 |
13 |
|
N2 |
Central |
City Hall |
Performing Arts Centre |
4.0 |
11 |
|
N3 |
Central |
PLA Headquarters |
Military |
4.9 |
4 |
|
N4 |
Wanchai |
HKAPA (Open Arena) |
Performing Arts Centre |
5.0 |
G/F |
|
N5 |
Wanchai |
Art Centre |
Performing Arts Centre |
4.0 |
10 |
|
N6 |
Wanchai |
HKCEC Extension |
Convention and Exhibition |
5.5 |
8 |
|
N7 |
Wanchai |
Causeway Centre |
Residential |
4.0 |
42 |
|
N8 |
Wanchai |
169-170 Gloucester Road |
Residential |
3.7 |
12 |
|
N11 |
Causeway Bay |
Elizabeth House |
Residential |
3.7 |
21 |
|
N12 |
Causeway Bay |
Riviera Mansion |
Residential |
4.3 |
15 |
|
N14 |
Causeway Bay |
Marco Polo Mansion (eastern façade) |
Residential |
4.3 |
15 |
|
N17 |
Tin Hau |
Mayson Garden Building |
Residential |
4.0 |
24 |
|
N19 |
Tin Hau |
Belle House |
Residential |
3.6 |
24 |
|
N21 |
Tin Hau |
Victoria Centre |
Residential |
4.0 |
30 |
Table 4.7 Summary
of Representative Existing and Planned Noise Sensitive Receivers for Traffic
Noise Impact Assessment
|
NSR |
Section |
Location |
Use |
Ground elevation (mPD) |
No. of Floors |
|
N1 |
Sheung Wan |
|
Residential |
3.8 |
13 |
|
N2 |
Central |
City Hall |
Performing Art Centre |
4.0 |
11 |
|
N4 |
Wanchai |
HKAPA (Open arena) |
Performing Art Centre |
5.0 |
G/F |
|
N5 |
Wanchai |
Art Centre |
Performing Arts Centre |
4.0 |
10 |
|
N6 |
Wanchai |
HKCEC Extension |
Convention and Exhibition |
5.5 |
8 |
|
N7 |
Wanchai |
Causeway Centre |
Residential |
4.0 |
42 |
|
N8 |
Wanchai |
169-170 Gloucester Road |
Residential |
3.7 |
12 |
|
N9 |
Wanchai |
Kam Kwok Building |
Residential |
3.7 |
18 |
|
N10 |
Wanchai |
Hyde Centre |
Residential |
3.7 |
22 |
|
N11 |
Causeway Bay |
Elizabeth House |
Residential |
3.7 |
21 |
|
N12 |
|
|
Residential |
4.3 |
15 |
|
N13 |
Causeway Bay |
Marco Polo Mansion (northern façade) |
Residential |
4.3 |
15 |
|
N14 |
Causeway Bay |
Marco Polo Mansion (eastern façade) |
Residential |
4.3 |
15 |
|
N15 |
Tin Hau |
Viking Garden |
Residential |
4.0 |
25 |
|
N16 |
Tin Hau |
Victoria Court |
Residential |
4.0 |
18 |
|
N17 |
Tin Hau |
Mayson Garden Building |
Residential |
4.0 |
24 |
|
N18 |
Tin Hau |
Gordon House |
Residential |
4.0 |
15 |
|
N19 |
Tin Hau |
Belle House |
Residential |
3.6 |
24 |
|
N20 |
Tin Hau |
Hoi Tao Building |
Residential |
4.0 |
30 |
|
N21a |
Tin Hau |
Victoria Centre (Tower 2) |
Residential |
4.0 |
30 |
|
N21b |
Tin Hau |
Victoria Centre (Tower 1) |
Residential |
4.0 |
30 |
|
N22 |
Tin Hau |
|
Residential |
4.3 |
44 |
|
N23 |
Wanchai |
Possible Tin Hau Temple Site |
Temple |
Future Development |
|
4.4.3
In this
project, three ventilation shaft buildings are proposed for the main tunnel
along the CWB & IECL. In order to
evaluate the fixed noise impacts, existing representative sensitive receivers
(Figure 4.1) have been identified near the proposed ventilation buildings. The
shortest distance between the ventilation buildings and the representative NSRs
are listed in Table 4.8. Since no NSRs
are located within 300 m of West Ventilation Building, no assessment for this ventilation
shaft is undertaken.
4.4.4
Some
NSRs such as PLA Headquarters, which are facing the tunnel section of the CWB
& IECL and are far away from the Central section / Causeway Bay section of
the CWB, would not be selected for traffic noise impact assessment as no
adverse traffic noise impacts from the proposed ‘new’ roads will be expected on
these NSRs.
4.4.5
According
to the latest information from WDII project, all the land uses of future
developments on the proposed reclamation land are commercial, hotels, museums,
temple and recreational facilities.
Museums for exhibition purpose, and recreational facilities are not
defined as NSRs according to Annex 13 of the EIAO-TM. Hotels and museums would be provided with central air-conditioning
system and they do not rely on openable window for ventilation. No adverse noise impact on these NSRs would
be expected. Therefore, these NSRs are
not selected for the assessment. Only
one future NSR, a temple that is located near Hing Fat Street, is identified.
Table 4.8 Summary
of Selected Noise Sensitive Receivers for Fixed Noise Impact Assessment
|
NSR |
Description |
Use |
Shortest Distance from the Louvres at WVB (m) |
Shortest Distance from the Louvres at CVB (m) |
Shortest Distance from the Louvres at EVB (m) |
|
N4 |
HKAPA (Open Arena) |
Performing Art Centre |
N/A |
172 |
N/A |
|
N5 |
Art Centre |
Performing Arts Centre |
N/A |
161 |
N/A |
|
N7 |
Causeway Centre |
Residential |
N/A |
N/A |
393 |
|
N9 |
Kam Kwok Building |
Residential |
N/A |
N/A |
272 |
|
N10 |
Hyde Centre |
Residential |
N/A |
N/A |
269 |
Note: WVB
– West Ventilation Building; CVB – Central Ventilation Building; EVB – East
Ventilation Building; N/A represents that the NSR is located out of 300 m from
the ventilation building and is not included in the assessment.
Construction Noise
4.5.1
The
methodology outlined in the TM on Noise from Construction Works other than
Percussive Piling has been used for the assessment of construction noise. Notional noise sources for different
construction areas were assumed in accordance with this TM. All items of powered mechanical equipment
(PME) were assumed to be located at these notional source positions.
4.5.2
Taking
into account the different construction periods of the Project and other
concurrent projects such as WDII and CRIII, the construction assessment has
been carried out on quarterly basis since commencement of the Project. The assessment period is from the first
quarter of 2004 to first quarter of 2012.
4.5.3
Powered
Mechanical Equipment (PMEs) for the different construction tasks are presented
in Appendix 4.1. The plant inventory
list has been confirmed as being practical and practicable in completing the
works within scheduled timeframe. Sound
power levels (SWLs) of PME were taken from Table 3 of the TM on Noise from
Construction Work other than Percussive Piling.
4.5.4
A
positive correction of 3 dB(A) was made to the calculated result in order to
allow for façade effect. The boundary
walls around HKAPA open arena are assumed as noise barriers and a 5 dB(A)
reduction of the predicted noise levels at NSR N4 is expected due to the
shielding effect.
4.5.5
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 SWL
of each construction task was calculated, depending on the number of plants,
their frequency of operation, and their distance from receivers. The noise levels at NSRs were then predicted
by adding up the sound pressure level of all concurrently construction tasks.
4.5.6
Construction
tasks, including construction works from other projects taking place within 500
m of a given NSR at the same period, 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 minimum distances from
the notional source point of each construction activity to the representative
NSRs are given in Appendix 4.2.
4.5.7
The
construction of the CWB & IECL is divided into several phases. The CWB
& IECL tunnel works that pass through the CRIII and WDII area have been
entrusted to Territory Development Department (TDD). The foundation works for the
Central Interchange
Section (Figure 4.1.1)
·
construction of
CWB Tunnel section;
·
bridge foundation
works and deck construction;
·
bridge finishing
works;
·
at-grade roads
construction;
·
CWB West
Ventilation Building - foundation works and superstructure construction;
·
tunnel
modification at Road D5 junction; and
·
demolish Rumsey
Street Flyover Downramp and re-provide a slip road connecting Rumsey Street
Flyover.
Trunk Road (Exhibition Section)
(Figure 4.1.1)
·
CWB Central
Ventilation Building – superstructure construction.
Trunk Road (IECL Section) (Figure 4.1.2)
·
bridge foundation
and deck construction;
· bridge finishing works; and
·
CWB East Ventilation and
4.5.8
The
concurrently construction tasks undertaken by the CRIII and WDII are also
considered in the assessment. Locations
of other construction sites (CRIII & WDII) are shown in Figure 3.2. The major construction sites are listed as
follows:
Central Reclamation Phase III (CRIII):
· Initial Reclamation Area West (IRAW);
· Initial Reclamation Area East (IRAE);
· Final Reclamation Area West (FRAW); and
· Final Reclamation Area East (FRAE).
Wan Chai Development Phase II (WDII):
·
Hong Kong
Convention & Exhibition Centre (HKCEC) Reclamation Stage 1 – Water Channel
(HKCEC1);
·
HKCEC Reclamation
Stage 2 – West (HKCEC2W);
·
HKCEC Reclamation
Stage 2 – East (HKCEC2E);
·
Wanchai
Reclamation Stage 1 (WCR1);
·
Wanchai
Reclamation Stage 2 – West (WCR2W);
·
Wanchai
Reclamation Stage 2 – East (WCR2E);
·
Wanchai
Reclamation Stage 3 – West (WCR3W);
·
Wanchai
Reclamation Stage 3 – East (WCR3E);
·
Causeway Bay
Reclamation Stage 1 – West (CBR1W);
·
Causeway Bay
Reclamation Stage 1 – East (CBR1E);
·
Causeway Bay
Reclamation Stage 2 – West (CBR2W); and
·
Causeway Bay
Reclamation Stage 2 – East (CBR2E).
4.5.9
The
construction noise assessment in this study is based on the CWB & IECL
construction programme.
4.5.10 According to the latest programme
provided by the HyD, the construction of Causeway Bay Flyover, which is a
separate project from WDII and CWB & IECL projects, is scheduled to
commence in May 2003 for completion in February 2006. The construction period will be overlapped with the CWB project. Therefore, the impact arising from the
construction of Causeway Bay Flyover was also considered in the
assessment. For assessment purpose, the
same PMEs for Hung Hing Road Flyover has been adopted for Causeway Bay
Flyover. This has been confirmed as
being practical and practicable in completing the works within scheduled timeframe.
4.5.11 The plant inventory and SWL associated with tunnel construction works in CRIII and WDII areas are in accordance with the CRIII EIA Report([1]) and the WDII EIA Report([2]), respectively. The plant inventory for tunnel work and other concurrent construction of WDII projects are listed in Appendix 4.1. The construction activities considered in the assessment during each quarter for each NSR are listed in details presented in Appendix 4.2.
4.5.12 The assessment results and the
proposed noise mitigation measures for construction tasks in the CRIII EIA
Report are also adopted in this assessment.
4.5.13 Bridge construction for certain
sections of IECL and some modified road works at Rumsey Street Flyover would be
carried out at mid-night to minimise traffic impacts due to road diversion
works. According to GW-TM, for any
construction works planned during the restricted hours, the Contractor will be
required to submit CNP applications to the Noise Control Authority and has the
responsibility to ensure compliance with the NCO and relevant TM. Therefore, the potential noise impacts of
construction works proposed within the restricted hours are not formally
assessed within this EIA (see section 4.2.5).
4.5.14 Traffic noise was predicted using
the methodology provided by the UK Department of Transport Calculation of Road
Traffic Noise (CRTN) 1988. The
assessment was based on projected peak hour flows for the worst year within 15
years after opening of the road. The
road is scheduled to be operation in 2012.
Therefore, the traffic data for 2027, which is endorsed by Transport
Department, is adopted for the assessment (see Appendix 4.9). Since traffic flows at the major roads
during the peak hour in the morning session are generally higher than that in
the afternoon session, the morning peak hour traffic flows were used for
modelling. The projected 2027 morning
traffic flow is presented in Figures 3.3.1 to 3.3.6.
4.5.15 Traffic speeds for the proposed
Trunk Road system based on the Updated Design Memorandum Part A of the CWB
& IECL Project Review Study in May 2001 are adopted and summarised as
follows:
Road Speed Limit
CWB Trunk Road 80 km per hour
Slip Road and Operation Road 50 km per hour
4.5.16 The traffic speed limit for all
existing roads has been assumed to be 50 km per hour except the Island Eastern
Corridor and Rumsey Street Flyover, which has been assumed to be 80 km per
hour. The speed limit of Road P1/P2
will be 50 km per hour. According to
the “CWB & IECL Project Review Study, Updated Design Memorandum” in May 2001,
a friction course (porous asphalt) would be used on the expressways or trunk
roads with anticipated vehicular speed of 80 km per hour or above as the
recommendation in TPDM Volume 2 Chapter 6 Clauses 6.3.1.4 – 6.3.1.7 and Road
Note 5. In this assessment, friction
course (porous asphalt) is assumed on the Island Eastern Corridor, Rumsey
Street Flyover, and the new roads (that is, the CWB & IECL) where the speed
is 80 km per hour. The location of
porous asphalt road surfacing is shown in Figures 4.2.1 and 4.2.2.
4.5.17 The road network, proposed building
layout and all other features that could have noise screening or reflective
effects, were digitised in the road traffic noise model. The roads were divided into segments, each
of which was assigned a road layout number.
A road layout defined the road width, opposing traffic lane separation,
road surface type and traffic mix, flow and road design speed. Hard ground as defined in CRTN was assumed
throughout the Study Area. Noise levels
were calculated at each receiver point at three different elevations (that is,
1st floor, mid-floor and top floor). A
sample of modelling listing file is included in Appendix 4.5.
4.5.18 Three ventilation buildings for the
main tunnel, as shown in Figure 4.3, are proposed along the CWB & IECL.
4.5.19 Potential noise impacts from the
ventilation buildings with exhaust fans would be expected on the sensitive
receivers. The fixed plant noise impact
arising from these ventilation buildings has been assessed in accordance with
the IND-TM.
4.5.20 According to Final Working Paper on
Tunnel Electrical and Mechanical System (WP03) of CWB & IECL Design and
Construction Assignment in November 2000 and the information provided by the
Ventilation Engineer, 5 duty plus 2 standby exhaust fans are proposed for East
Ventilation Building (EVB). For Central
Ventilation Building (CVB) and Western Ventilation Building (WVB), 3 duty plus
2 standby exhaust fans and 3 duty plus 1 standby fans are proposed,
respectively. Table 4.9 summarises the numbers
of exhaust fans required for the proposed ventilation buildings during normal
condition.
Table 4.9 The
Number of Exhaust Fans required for Proposed Ventilation Buildings during
|
Ventilation Building |
Fan Capacity (m3 s-1) |
Number of Exhaust Fans Required |
|
East Ventilation Building |
190 100 |
3 (+1 standby) 2 (+1 standby) |
|
Central Ventilation Building |
100 90 |
1 (+1 standby) 2 (+1 standby) |
|
Western Ventilation Building |
140 |
3 (+1 standby) |
4.5.21 It has assumed that all duty exhaust
fans at each ventilation building are operated in the assessment. Screening corrections from other buildings /
structures and directivity have also been excluded in the assessment. The information provided by the Ventilation
Engineer that all the exhaust fans installed in each ventilation buildings will
be provided with silencers. Since the
use of silencers will flatten the frequency band of the exhaust fan, no
tonality correction is considered in the calculation.
4.5.22 According to the East Kowloon Line /
North Hong Kong Island Line (NHKIL) Feasibility Study Report issued in
September 1999, the proposed ventilation buildings for NHKIL would be located
near the junction of
4.6 Prediction and Evaluation of Environmental Impacts
Construction Noise
4.6.1
The
construction period for whole Project is about 96 months from March 2004 to
February 2012. In general, there are six sections of construction works during
the construction period:
(a) CWB Tunnel – March 2004 to March
2008;
(b) Central Interchange – September 2005
to August 2008;
(c) IEC Link – December 2007 to August
2011;
(d) Demolition of temporary ramp
structures – September 2011 to October 2011;
(f)
Modification
works at existing Rumsey Street (RS) Flyover and upramp and demolition of
downramp of RS – September 2011 to February 2012.
4.6.2
In the absence of any mitigation measures, exceedance of
the Leq (30 minutes) 75 dB(A) construction noise criterion for
residential uses is predicted at most of the representative NSRs. Details of construction noise calculations and results are presented in
Appendix 4.2. Results showed that the
predicted noise levels at the representative NSRs were in the range between 55
and 93 dB(A) during the construction years of CWB & IECL. A summary of the unmitigated construction
noise levels of the representative NSRs during normal daytime working hours
within the CWB & IECL construction period is listed in Table 4.10.
Table 4.10 Summary
of Unmitigated Construction Noise Levels during Normal Daytime Working Hours
|
Representative
NSRs |
Predicted
Unmitigated Construction Noise Levels during Normal Daytime Working Hour(1)
(0700 to 1900 on weekday) (dB(A)) |
|
N1 |
66 – 80 |
|
N2 |
55 – 80 |
|
N3 |
64 – 93 |
|
N4 |
60 – 78 |
|
N5 |
68 – 85 |
|
N6 |
59 – 89 |
|
N7 |
62 – 83 |
|
N8 |
62 – 81 |
|
N11 |
60 – 81 |
|
N12 |
72 – 77 |
|
N14 |
74 – 85 |
|
N17 |
66 – 81 |
|
N19 |
67 – 83 |
|
N21 |
66 – 86 |
Note: (1) For normal daytime working hours, the noise criterion for N2 and N5 is 70 dB(A). The criterion for other NSRs is 75 dB(A).
4.6.3
According
to the results, all NSRs in the Central Interchange area and its vicinity
(namely NSRs N1, N2 and N3) would not comply with the construction noise
standard. The exceedance at PLA
Headquarters (NSR N3) is dominantly due to CRIII project. Since City Hall (NSR N2) is provided with
central air conditioning and noise insulated facilities, no adverse noise
impact is expected at the indoor of this NSR.
Therefore, noise mitigation measures such as using quiet plant are
recommended for the construction tasks in Central Interchange Area to alleviate
the construction noise impacts on NSR N1 only.
The representative NSRs in Wan Chai area and Causeway Bay area would be
affected by WDII project and CWB & IECL project. Practical mitigation measures such as quiet plants or movable
noise barriers (Section 4.7) should be implemented in order to reduce noise
levels to the stipulated standard.
4.6.4
Traffic
noise levels have been calculated at a total of 23 representative NSRs
including existing residential dwellings, performing art centres and one
temple. The assessment results of the NSRs are listed in Appendices 4.4 and
4.7.
Central
Interchange Section (Figure 4.1.1)
4.6.5
There
is only one representative NSR near the Central Interchange section. It is predicted that the noise level at NSR
N1 would exceed the statutory limit by 10 to 13 dB(A). However, the noise exceedances are
attributed to the existing roads. The
noise level contributed from the proposed ‘new’ roads is not more than 70 dB(A)
and the ‘new’ road noise contribution to the overall noise level is less than
1.0 dB(A). Therefore, no direct noise
mitigation measure is recommended on the proposed Central Interchange section.
Exhibition Section (CWB Tunnel Section)
(Figure 4.1.1)
4.6.6
Generally,
there are a main enclosed trunk road and some slip roads in this section. The predicted noise levels at NSRs N2, N4 to
N7 exceed the EIAO-TM criteria. It is
predicted that the NSR N2 is dominantly affected by the existing roads and the
roads proposed in CRIII Project. The
other NSRs along this section are expected to be dominantly affected by the
existing roads and the proposed roads in WDII project. Only minimal noise levels contributed from
the proposed slip roads of this Project would be expected. Since the ‘new’ road noise contribution to
the overall noise level is less than 1.0 dB(A) and ‘new’ road noise level is
not more than 70 dB(A), no direct mitigation measure is proposed on the ‘new’
roads at this section.
IECL Section (Figure 4.1.2)
4.6.7
Noise
exceedance is predicted at most of the respective NSRs along this section. The existing road noise levels at all
representative NSRs exceed the statutory limit of 70 dB(A) due to high traffic
flow on the Gloucester Road and the existing Island Eastern Corridor. Besides, the proposed ‘new’road near the
Causeway Bay Typhoon Shelter and the Hing Fat Street upramp impose significant
noise impacts on some NSRs near Victoria Park Road and along Hing Fat
Street. Direct noise mitigation
measures (Section 4.7.11) are therefore required on the proposed ‘new’roads to
alleviate the traffic noise impacts on these affected NSRs.
4.6.8
Since
the exhaust fans are expected to be operated 24 hours daily, referring to Table
4.4, the calculation will be based on the stringent fixed noise night-time
criteria of 50 / 55 dB(A) in the assessment according to EIAO-TM
requirement. It is assumed all duty
exhaust fans are operated for each ventilation building during assessment. As the distances among the three proposed
buildings are quite far away to each other, no cumulative fixed noise impact is
determined in this case.
4.6.9
As
directivity and screening corrections have not been included in the assessment,
the predicted noise levels at NSRs represent the worst case scenario. Correction for tonality has not been
considered in the assessment as the use of silencers will flatten the frequency
band of the exhaust fans. Details of
calculations of predicted noise levels at NSRs are shown in Appendix 4.6.
4.6.10 According to Table 4.11, there will
be no exceedance of night-time criteria specified in the EIAO-TM at the
identified NSRs if silencers are provided at all exhaust fans of each
ventilation building.
4.6.11 According to the CRIII EIA Report,
no adverse fixed noise impacts are expected on the closest NSR, and it is
located far away from three proposed ventilation building. Therefore, no cumulative fixed noise impacts
are expected.
4.6.12 According
to the East Kowloon Line / North Island Line Feasibility Study Report in
September 1999, the proposed ventilation buildings for North Island Line would
be located near the junction of Fleming Road and Convention Avenue (VB1) and
Tonnochy Road near Harbour Road Indoor Games Hall (VB2), respectively. It is noted that the proposed NHKIL has to
undergo a statutory EIA and noise emission from the NHKIL ventilation shafts
have to comply with the statutory standards under the EIAO-TM’s and NCO’s
requirements. The location of VB2 is
near EVB but their separation distance is about 280 m. According to the findings from WDII EIA
Report([3]), the
sound power level arising from VB2 should not be more than 96.4 dB(A) so that
the nearest NSR (Causeway Centre) complies with the night-time fixed noise
criterion of 50 dB(A). It is expected
that noise arising from ventilation shaft would fulfill the requirement with
the installation of acoustic silencers.
Therefore, no adverse cumulative fixed noise impacts are anticipated at
the NSRs close to both EVB and VB2.
Table 4.11 Predicted Fixed Noise
Levels at NSRs (Leq, 30 min dB(A))
|
NSR |
Description |
Predicted
Noise Levels, dB(A) (not including ventilation shaft noise from VB2 for
NHKIL) |
Night-time
Criterion in NCO / EIAO-TM |
|
N4 |
HKAPA |
46.3 |
60 / 55 |
|
N5 |
Art
Centre |
46.9 |
55 / 50 |
|
N7 |
Causeway
Centre |
44.0 |
55 / 50 |
|
N9 |
Kam
Kwok Building |
47.2 |
60 / 55 |
|
N10 |
Hyde
Centre |
47.3 |
60 / 55 |
Note: * The location of VB1 is far away from the NSR,
no cumulative noise impact is expected.
4.7 Mitigation of Adverse Environmental Impacts
Construction Noise
Adoption of Quiet
PMEs
4.7.1
In
order to reduce the excessive noise impacts at the affected NSRs during normal
daytime working hours, mitigation measures such as adopting quiet plant,
erection of noise barriers and reducing on-time operation of the plant, are
appropriate to be used. One of feasible
solution is to adopt quieter construction plant for several construction tasks
during all or part of construction years.
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, however, 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.
4.7.2
In
this assessment, the recommended silenced PMEs are taken from the BS 5228: Part
1: 1997, which are known to be in Hong Kong.
The quiet PMEs adopted for CWB construction activities are considered
practical and practicable in completing the works within schedule. The quiet
PMEs adopted for the CRIII and WDII construction tasks are in accordance with
CRIII EIA Report([4])
and WDII EIA Report([5]).
4.7.3
The
lists of silenced PME adopted in the assessment are shown in Appendix 4.1. The following construction tasks of CWB
& IECL are considered to adopt quiet PMEs:
· CWB Tunnel in HKCEC1, HKCEC2E, HKCEC2W, WCR1, WCR2E, WCR2W and WCR3W;
· piling, tunnel and deck construction in Mass Transit Railway tunnel crossing area;
· demolition of existing IEC structure, bridge formation, deck formation, road formation and earthwork, road pavement at IECL section,
· tunnel buildings, and
· demolition of downramp of Rumsey Street.
4.7.4
According
to the information provided by the HyD([6]),
the construction noise levels arising from the construction of Causeway Bay
Flyover at the closest NSRs will comply with the construction noise criteria
with the implementation of appropriate mitigation measures.
4.7.5
The
construction tasks adopting quiet PMEs in WDII project are listed as follows:
WDII Construction Tasks
· Flyover Road P1/P2 to Fenwick Pier near the HKAPA and the Art Centre;
· Road P1/P2 near the HKAPA, the Art Centre and the HKCEC Extension;
· HKCEC Roads;
· Local access roads near the HKAPA and the Art Centre;
· Wan Chai North Public Transport Interchange;
· Demolition of East Bridge (WCR2E) and West Bridge (HKCEC2);
· Demolition of Ferry Structure and Reprovision of East Pier and West Pier;
· Hung Hing Road Flyover;
· Drainage culverts in CBR1E, CBR1W,CBR2E, WCR1,WCR2E and HKCEC2;
· Cross Harbour Watermains – Land section; and
·
Cooling water intake pipeline in
HKCEC1 near HKAPA, HKCEC2 West near HKAPA and Art Centre, and CBR1 near
4.7.6
As
shown in Appendix 4.2, with the use of the quiet equipment, the overall noise
levels at NSRs could be reduced by 1 to 11 dB(A), depending on the type of
construction activities. The predicted
noise levels at the performing art centres such as the Art Centre and the HKCEC
Extension still do not comply with the construction noise standard. However, it is known that central
air-conditioning system and noise insulated facilities have been provided at
the HKCEC Extension and the Art Centre.
In addition, they do not rely on openable windows for ventilation, no
adverse noise impacts will therefore be expected at the indoor of these
NSRs. Nevertheless, the predicted
construction noise levels relating to the CWB project at a residential
representative NSR (Victoria Centre) would still be non-compliant with the
EIAO-TM construction noise criteria.
Additional noise mitigation measures such as temporary noise barrier
should be provided.
Movable Noise Barrier
4.7.7
In order
to alleviate the construction noise impacts on the affected NSRs, movable noise
barriers are provided for particular plants.
According to GW-TM, it is anticipated that a movable noise barrier with
a cantilevered upper portion located to the noise generating part of the PME
can produce 5 dB(A) or up to 10 dB(A) noise screening, depending on the line of
sight that could be blocked by the barriers when viewed from the NSR. The noise screening benefit for each plant
considered in this assessment is listed as follows:
· Stationary plant – assuming 10 dB(A) reduction: concrete pump, compressor and poker vibrator;
· Mobile plant – assuming 5 dB(A) reduction: excavator, mobile crane, grader and road roller.
4.7.8 The movable noise barriers are considered to be adopted for the following construction activities:
· HKCEC2E – Diaphragm Wall;
· HKCEC2W – Diaphragm Wall and Excavation;
· Bridge M – Foundation and Deck Formation at Stage 2;
· Bridge L – Deck Formation at Stage 2;
· Deck of Bridges E6, E7 and E8 – Deck Formation at Stage 2;
· Demolition of Existing IEC Structure, Substructure of Bridges W5, W6 and Bridge J and Deck of Bridges W5 and W6 at Stage 4A/4B.
4.7.9
With
the installation of noise barriers, exceedance is still predicted at the
Victoria Centre and the HKAPA (open arena).
Reduction in number of PME or / and PME percentage on-time are required
to alleviate the construction noise impacts to comply with the established
criteria.
Reduction in
Number of PME and PME Percentage On-time
4.7.10 The following tasks are proposed to
reduce the number of plant so as to reduce the noise impacts on the affected
NSRs.
· Bridge M – Deck formation at Stage 2;
· Demolition of existing Island Eastern Corridor structure at Stage 4A;
· CWB tunnel (HKCEC2W) – Diaphragm wall and excavation.
4.7.11 Since PMEs would not be fully
operated in practice, appropriate on-time percentage of some plants during
foundation work of Bridge M, deck formation for Bridges E6 and E7, deck
formation for Bridge E8 and substructure of Bridges W5, W6 and Bridge J are
recommended when these construction activities are close to the Victoria
Centre. The reduction of on-time
operation is expected to be practical and practicable in completing the works
within the schedule. The locations of
relevant construction activities are shown in Figures A4.4 to A4.11 of Appendix
4.8.
4.7.12 With the use of the above mitigation
measures, the predicted construction noise levels at the Victoria Centre would
comply with the construction noise standard.
Exceedance is still predicted at PLA Headquarters, dominantly due to
CRIII construction works. According to
the noise mitigation measures for CRIII construction works presented in the EIA
Report of the CRIII project([7]),
movable noise barriers would be adopted for the Hong Kong Station Extended
Overrun Tunnel (EOT), NHKIL protection works and road / drainage works
immediately to the north of the PLA Headquarters. These would reduce noise levels by at least 5 dB(A). It should, however, be noted that the PLA
Headquarters are already provided with air conditioning and therefore the noise
levels predicted after the adoption of quiet PMEs and movable noise barriers
would not result in adverse noise impacts to the buildings. Table 4.12 summarises the mitigated noise
levels during normal daytime working hours at representative NSRs.
Table 4.12 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(1)
(0700 to 1900 on weekday) (dB(A)) |
|
N1 |
66 – 74 |
|
N2 |
55 – 80 |
|
N3 |
64 – 84 |
|
N4 |
58 – 71 |
|
N5 |
68 – 79 |
|
N6 |
59 – 82 |
|
N7 |
62 – 75 |
|
N8 |
62 – 73 |
|
N11 |
60 – 74 |
|
N12 |
57 – 74 |
|
N14 |
67 – 75 (2) |
|
N17 |
66 – 75 |
|
N19 |
60 – 75 |
|
N21 |
59 – 75 |
Note: (1) For normal daytime working hours, the noise
criterion for N2 and N5 is 70 dB(A).
The criterion for other NSRs is 75 dB(A).
(2) According
to information provided by the Highways Department, the construction noise impacts
of the Causeway Bay Flyover project would be mitigated through proper
implementation of appropriate noise control measures to ensure the noise levels
comply with construction noise standards.
Traffic Noise
4.7.13 The following direct mitigation
measures (DMMs) are proposed to reduce the traffic noise impact arising from
the IECL section:
· a 107 m long semi-enclosure for the eastbound carriageway of IECL (CH4883 – CH4990) (the roof covers the whole eastbound carriageway, solid vertical structure is provided at central divider from CH4930 – CH4990, support columns are provided at central divider from CH4883 – CH4930 and the west side of eastbound carriageway);
· a 57 m long semi-enclosure for the westbound carriageway of IECL (CH4883 – CH4940) (the roof covers the whole westbound carriageway, solid vertical structure is provided at the south side of westbound carriageway and support columns are provided at central divider);
· a 113 m long and 7 m high vertical barrier, located at the edge of the parapet of the westbound carriageway of IECL (CH4770 – CH 4883);
· a 210 m long and 7 m high vertical barrier located at the edge of the parapet of the Slip Road J (CH350 - CH560);
· a 139 m long and 5.5 m high vertical barrier, located at the edge of the parapet of the westbound carriageway of IECL (CH4116 – CH4255);
· a 140 m long and 4 m high vertical barrier, located at the edge of the parapet of the westbound carriageway of IECL (CH4630 – CH4770);
· a 81 m long cantilevered barrier (5.5 m high vertical barrier with 2 m cantilever length at 45 degrees to the horizontal) located at the central divider of IECL (CH4802 - CH4883); and
· a 259 m long cantilevered barrier (5.5 m high vertical barrier with 2 m cantilever length at 45 degrees to the horizontal) located at the edge of the parapet of the westbound carriageway of IECL (CH4255 – CH4514).
4.7.14 The proposed DMMs mentioned in the
paragraph above are shown in Figure 4.4 and the typical section drawings are
shown in Figures 7.7.1 and 7.7.2. The
recommended barriers can be in the form of concrete or transparent panel, and
this would be considered in the detailed design stage. The predicted mitigated results are
presented in Appendix 4.4.
4.7.15 With
the implementation of the proposed DMMs on the IECL section, the noise levels
at most of the representative NSRs in Causeway Bay (such as Elizabeth House and
Marco Polo Mansion) and Tin Hau area (such as Viking Garden and Belle House)
are still not compliant with the traffic noise criterion. Exceedance is also predicted at City Garden,
which is at the study area boundary. However, except the low to top floors of
both NSRs N21a and N21b (Victoria Centre), the noise levels arising from ‘new’
roads in CWB & IECL project at all the representative NSRs and City Garden
are below 70 dB(A) and the ‘new’ road noise contributions to the overall noise
levels at these representative NSRs are less than 1.0 dB(A). Therefore, no further direct mitigation
measures on the ‘new’ roads are provided for these NSRs. On the other hand,
further direct mitigation measures have to be investigated for the low to top
floors of NSRs N21a and N21b.
4.7.16 The
dominant noise sources at NSRs N21a and N21b are the section of IECL and
existing IEC in front of Victoria Centre.
A section of semi-enclosure between chainage 4883 and 4990 has been
proposed to cover the IECL westbound. Extension of this semi-enclosure eastward
is not feasible since the structure would cause sightline problem near the diverging
point of the
4.7.17 According
to the new policy guideline issued in November 2000 on the provision of
measures to address noise impact of existing roads, engineering solutions by
way of retrofitting of barriers and enclosures, and resurfacing with low noise
material should be implemented where practicable on existing excessively noisy
roads. It is clear from the above noise
assessment that a residential block, i.e. N22, is likely to be adversely
affected by the section of the existing IEC near the eastern end of the project
limit. Friction course has been provided at the existing IEC to reduce the
traffic noise impacts on this noise sensitive receiver. However, installation of barriers or
enclosures on this section of the road would be severely restricted by site
conditions and the need to resume private lots. It is considered not feasible to
erect a noise barrier or an enclosure of, say, 7m high, on the existing bridge
structure, as the bridge was again not designed to withstand the additional
wind load from the noise barrier or enclosure. On the other hand, if the noise
barrier or enclosure is to be constructed on the existing ground, the
supporting structure, which would consist a number of above 10m high, closely
spaced columns, and the noise barrier or enclosure itself, would seriously
obstruct the sea view at the lower five storeys of Harbour Heights. Resumption
of private lots for construction of this noise barrier would be difficult as
there is at present no policy that would enable this to be proceeded. Therefore, no further mitigation measures
could be provided at these locations.
4.7.18 As
all DMMs have been exhausted, the NSRs would be evaluated to determine whether
they are eligible for the provision of indirect technical remedies (ITR) in the
form of window insulation and air-conditioners. Detailed assessment results are presented in Appendix 4.7.
Ventilation Shaft Noise
4.7.19 No exceedance is expected on the
representative NSRs, therefore no mitigation measure is recommended for the
proposed EVB, WVB and CVB in this study.
It is recommended that, wherever possible, the louvres should face away
from the NSRs to further reduce the noise levels at NSRs. No adverse cumulative fixed noise impacts
are anticipated at the NSRs close to both EVB and VB2.
4.8 Evaluation of Residual Impacts
Construction Noise
4.8.1
With
the implementation of the above-mentioned mitigation measures, the construction
noise levels at all representative NSRs are predicted to comply with the noise
standard stipulated in EIAO-TM. The
above mitigation measures have been confirmed as being practical and
practicable in completing the works within scheduled timeframe. Residual impacts are therefore not
anticipated.
4.8.2
In addition to the above-mentioned mitigation measures,
the good site practices listed below should be adopted by all the Contractors
to further ameliorate the noise impacts.
Although the noise mitigating effects are not easily quantifiable and
the benefits are specific to the site and operating conditions, good site
practices are easy to implement and do not impact upon the works schedule.
·
Only
well-maintained plant should be operated on-site and plant should be serviced
regularly during the construction programme.
·
Silencers
or mufflers on construction equipment should be utilised and should be properly
maintained during the construction programme.
·
Mobile
plant, if any, should be sited as far away from NSRs as possible.
·
Machines
and plant (such as trucks) that may be in intermittent use should be shut down
between work periods or should be throttled down to a minimum.
·
Plant
known to emit noise strongly in one direction should, where possible, be
orientated so that the noise is directed away from the nearby NSRs.
·
Material
stockpiles and other structures should be effectively utilised, where
practicable, in screening noise from on-site construction activities.
Traffic Noise
4.8.3
With the
implementation of recommended noise barriers and semi-enclosures, the noise
level arising from ‘new’ roads in the CWB & IECL project at two
representative NSRs N21a and N21b would still exceed the traffic noise
criterion (70 dB(A)). It is estimated
that the total number of dwellings at Victoria Centre that ‘new’ roads noise
levels are higher than 70 dB(A) are 243 at N21a (from low to top floors) and
N21b (from low to top floors). At about
162 of these 243 dwellings, the contribution to the increase in the predicted
overall noise from ‘new’ road is greater than 1.0 dB(A). In order to redress the residual impact,
indirect technical remedies in the form of window insulation and
air-conditioning may need to be considered subject to the fulfilment of EPD’s
eligibility criteria for consideration by the Exco. Traffic flows in 2003 have been adopted for the prevailing
traffic noise assessment. Eligibility
assessment results and Year 2003 traffic flow are presented in Appendix 4.7.
4.8.4
According
to the results for NSR N21a, the predicted mitigated overall noise levels are
less than the prevailing noise levels.
For NSR N21b, the contribution to the increase in the predicted overall
noise from the ‘new’ road is less than 1.0 dB(A). Therefore, they will not meet the ExCo directive criteria for
noise insulation after the implementation of the recommended direct mitigation
measures.
Ventilation Noise
4.8.5
No
residual fixed plant noise impacts arising from the proposed EVB, CVB and WVB
are expected, provided that all exhaust fans at the proposed three ventilation
buildings are equipped with silencers.
4.9 Environmental Monitoring and Audit
Construction Phase
4.9.1
An
Environmental Monitoring and Audit (EM&A) programme has been established
according to the predicted occurrence of noisy activities. All the recommended mitigation measures
should be incorporated into the EM&A programme for implementation during
construction. Details of programme are
provided in the stand-alone EM&A Manual.
Operational Phase
4.9.2
Monitoring
of operation noise is considered necessary to verify the effectiveness of the
mitigation scheme. It is recommended
that the traffic noise monitoring should be carried out at representative NSRs
within one year of the road opening.
Operational noise monitoring will also be required during the
commissioning stage of the ventilation buildings to ensure that compliance with
the noise limits specified in this report has been achieved.
4.9.3
The
recommended mitigation measures, monitoring procedures and locations are
presented in the stand-alone EM&A Manual.
Construction Phase
4.10.1
This assessment has predicted the construction noise
impacts associated with the construction works of the proposed Project and
other concurrent projects including the CRIII, the WDII and the Causeway Bay
Flyover. With the use of silenced
equipment, the use of movable noise barriers for some plants, reduction in
equipment number and on-time operation at some specific construction plants,
all residential NSRs comply with the stipulated criteria. Noise exceedances are still predicted at the
City Hall, the Art Centre and the HKCEC Extension. However, these NSRs are equipped with central air-conditioning
system and good noise insulation facilities.
In addition, they do not rely on openable windows for ventilation, and
adverse noise impacts are therefore not expected at the indoor of these NSRs
and further mitigation measures for these NSRs will not be required. Exceedance is also predicted at the PLA
Headquarters dominantly due to construction noise from CRIII project. According to the noise mitigation measures for CRIII construction works
presented in the EIA report of the CRIII project, movable noise barriers would
be adopted for the EOT, NHKIL Protection Works and road / drainage works
immediately to the north of the PLA Headquarters. These would reduce noise levels by at least 5 dB(A). It should, however, be noted that the PLA
Headquarters are already provided with air conditioning and, therefore, the
noise levels predicted after the adoption of quiet PMEs and movable noise
barriers would not result in adverse noise impacts to the indoor environment of
the buildings.
Operational Phase
4.10.2 The
potential road traffic noise impacts have been assessed for the worst case
traffic flows in 2027. Most of the noise
sensitive receivers are predicted to exceed the EIAO-TM traffic noise
criteria. Direct mitigation measures
such as vertical barriers, cantilevered barriers and semi-enclosure have been
proposed on the ‘new’ roads to alleviate the traffic noise impacts. With the implementation of all recommended
practicable direct mitigation measures, exceedances are still predicted at most
of the NSRs mainly due to noise contribution from existing roads. As all direct mitigation measures are
exhausted, eligibility assessment for the provision of indirect technical
remedies has been undertaken for these NSRs.
4.10.3 According to the eligibility
assessment results, no NSRs are eligible for the consideration of indirect
technical remedies in the form of window insulation and air-conditioning since
none of them could fulfil all of the eligibility criteria.
4.10.4 The predicted ventilation shaft noise levels at the NSRs in the vicinity of the proposed ventilation buildings in this study would comply with the EIAO-TM criterion if silencers are provided at all exhaust fans of the proposed three ventilation buildings and included in the design specification. No adverse cumulative fixed noise impacts are anticipated with the consideration of ventilation shaft noise impacts from NHKIL at the NSRs close to EVB and VB2.
(1) Atkins China Ltd. (June 2001). Central Reclamation Phase III Comprehensive
Feasibility Study for Minimum Option, Final EIA Report.
([2])
Maunsell Consultants Asia Ltd. (June
2001). Wan Chai Development Phase II
Comprehensive Feasibility Study, EIA Report.
([3]) Maunsell Asia Ltd. (June 2000). Wan Chai Development Phase II, Comprehensive
Feasibility Study, Environmental Assessment Study, EIA Report.
([4]) Atkins China Ltd. (June 2001). Central Reclamation Phase III Comprehensive
Feasibility Study for Minimum Option, Final EIA Report.
([5])
Maunsell Consultants Asia Ltd. (June
2001). Wan Chai Development Phase II
Comprehensive Feasibility Study, EIA Report.
([6]) Fax communication between the Highways
Department and the consultant (Ref: (18) in HH 710/95 (8) XV (DWC), dated 29
May 2001).
([7]) Atkins China Ltd. (June 2001). Central Reclamation Phase III Comprehensive
Feasibility Study for Minimum Option, Final EIA Report.