5.1.1
This Section
provides an evaluation of the potential noise impacts arising from the
construction and operation of the proposed Project. Appropriate mitigation measures will be
recommended, where necessary, in order to mitigate any unacceptable impacts.
5.2
Environmental Legislation, Policies, Standards and
Criteria
Construction Phase
5.2.1
The principal legislation relating to the control of
construction noise is the Environmental
Impact Assessment Ordinance (Cap. 499).
The Technical Memorandum on
Environmental Impact Assessment Process (EIAO-TM), issued under the EIAO,
provides guidelines and noise criteria for evaluating noise impacts. The assessment criteria are defined in Annex 5 of the EIAO-TM.
5.2.2
The Noise Control Ordinance
(NCO) (Cap. 400) also provides means to assess construction noise
impacts. A number of Technical Memoranda
(TMs) have been issued under the NCO to
stipulate control approaches and criteria.
The Technical Memorandum on Noise
from Construction Work Other than Percussive Piling (GW-TM) provides the
guidelines for controlling the construction noise from powered mechanical
equipment (PME) in general construction works during the restricted hours. The Technical Memorandum on Noise from
Construction Works in Designated Areas (DA-TM) provides the guidelines for
controlling the use of Specified Powered Mechanical
Equipment (SPME) and the undertaking of Prescribed
Construction Work (PCW) during the restricted hours in a designated area.
General
Construction Works during Normal Working Hours
5.2.3
Under the EIAO,
potential noise impact arising from general construction works during normal
working hours (i.e. 0700 to 1900 hrs on any day not being a Sunday or general
holiday) at 1 m from the external façade of the noise sensitive uses, which
rely on opened windows for ventilation, is to be assessed in accordance with
the noise criteria specified in the EIAO-TM. The EIAO-TM
noise standards are presented in Table 5.1.
Table
5.1 EIAO-TM
Day-time Construction Noise Standards
|
Noise
Sensitive Uses |
Noise Standard 0700 to 1900 hours
on any day not being a Sunday or general holiday Leq, 30 min (dB(A)) |
|
·
All domestics premises including temporary
housing accommodation |
75 |
|
·
Hotels and hostels |
75 |
|
·
Educational Institutions including
kindergartens, nurseries and all others where unaided voice communication is
required |
70 65 (During
examinations) |
|
Notes: (1) The
above standards apply to uses which rely on opened windows for ventilation. (2) The
above standards shall be viewed as the maximum permissible noise levels
assessed at 1m from the external façade. |
|
General
Construction Works during Restricted Hours
5.2.4
The NCO provides
statutory controls on general construction works during restricted hours (i.e.
1900 to 0700 hours or any time on Sundays or general holidays). The use of PME for carrying out construction
works during these restricted hours would require a Construction Noise Permit
(CNP). The Noise Control Authority will assess all CNP applications on a
case-by-case basis and, in doing so the authority advises that they will be
guided by the GW-TM.
5.2.5
When assessing an application for CNP for the use of PME
during restricted hours, the Noise Control Authority will compare the
Acceptable Noise Levels (ANLs) specified in the GW-TM with the Corrected Noise Levels (CNLs) (i.e. after accounting
for factors such as barrier effects and reflections) associated with the
proposed PME operations. The NCO requires that noise levels from
construction at affected Noise Sensitive Receiver (NSR) be less than the
specified ANL. The ANLs are related to
the inherent noise sensitivity of the noise receiver areas in question, and
different Area Sensitivity Ratings (ASRs, i.e. A, B or C, see Table 5.2) have been
established to reflect the background characteristics of different areas. Each noise receiver area is assigned an ASR
based on its predominant land use and the presence, if any, of Influencing
Factors (IFs) such as nearby industrial areas, major roads or airports. The appropriate ASR for the NSR is determined
with reference to Table 5.2.
Table 5.2 Area Sensitivity Ratings
|
Degree to which NSR is affected by
Influencing Factor (IF) |
|||
|
Not Affected |
Indirectly Affected |
Directly Affected |
|
|
Rural area, including Country
Parks or village type developments |
A |
B |
B |
|
Low density residential area
consisting of low-rise or isolated high-rise developments |
A |
B |
C |
|
Urban area |
B |
C |
C |
|
Area other than those above |
B |
B |
C |
|
Notes: The following definitions apply: (a)
"Country Park" means an area that is designated
as a country park pursuant to section 14 of the Country Parks Ordinance;
(b)
"directly affected" means that the NSR is at such
a location that noise generated by the IF is readily noticeable at the NSR
and is a dominant feature of the noise climate of the NSR; (c)
"indirectly affected" means that the NSR is at
such a location that noise generated by the IF, whilst noticeable at the NSR,
is not a dominant feature of the noise climate of the NSR; (d)
"not affected" means that the NSR is at such a
location that noise generated by the IF is not noticeable at the NSR; and (e)
"urban area" means an area of high density,
diverse development including a mixture of such elements as industrial
activities, major trade or commercial activities and residential premises. |
|||
5.2.6
The relevant ANLs for each ASR are shown in Table 5.3.
Table 5.3 Acceptable Noise
Levels (ANLs) for General Construction Works to be carried out during Restricted
Hours (GW-TM)
|
Time
period |
Area Sensitivity Rating Leq, 5 min (dB(A)) |
||
|
|
A |
B |
C |
|
All days during the evening (i.e.
1900-2300 hrs) and general holidays (including Sundays) during the day and
evening (i.e. 0700-2300 hrs) |
60 |
65 |
70 |
|
All days during the night-time (i.e.
2300-0700 hrs) |
45 |
50 |
55 |
|
Note: (a) The above standard applies to uses
which rely on opened windows for ventilation. |
|||
5.2.8
The DA-TM issued
under the NCO indicates a list of
SPME and the types of PCW to be regulated within restricted hours in Designated
Areas (DAs). Under the DA-TM, the use of five types of SPME and
the carrying out of three types of 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; and
·
Hammering.
5.2.9
Part of the Project Site (i.e. the southern section from the Long
Ping Station) falls within the designated area under the NCO. Hand-held breaker and concrete lorry mixer specified as SPME will
be used during the construction and the use of these SPME during the restricted
hours within the designated area shall be controlled by the TM-DA. The Noise Control Authority will
assess the CNP applications based on procedures and requirements as described
in the DA-TM. In general, it should not be presumed that a
CNP would be granted for the carrying out of PCW within a designated area
during the restricted hours. The CNP may
be granted for the execution of construction works within a designated area during
restricted hours involving the use of SPME if the relevant ANL and criteria
stipulated in the DA-TM can be
satisfied. In the EIA stage, no use of SPME is proposed for the construction works
within the designated area during the restricted hours.
Operation Phase
5.2.11
The noise criteria, in terms of ANLs, stipulated in the IND-TM apply for all days and general
holidays. The ANLs are dependent on the
ASR of the NSRs and the time of the day and are presented in Table 5.4.
Table 5.4 ANLs for Fixed Noise Source under NCO
|
Time Period |
Leq 30min (dB(A)) |
||
|
ASR “A” |
ASR “B” |
ASR “C” |
|
|
Day-time (0700 - 1900 hrs) |
60 |
65 |
70 |
|
Evening (1900 - 2300 hrs) |
60 |
65 |
70 |
|
Night-time (2300 - 0700 hrs) |
50 |
55 |
60 |
5.2.13
For the purpose of EIA, fixed plant noise associated with the
operation of a project is controlled under the EIAO. The noise standards are set out in the Annex 5 of EIAO-TM as follows:
·
The total fixed
source noise level at the façade of the nearest NSR is at least 5 dB(A) lower
than the appropriate ANL (as shown in Table 5.4) as
specified in the IND-TM; or
·
Where the prevailing
noise level in the area is 5 dB(A) or more below the appropriate ANL, the total
fixed source noise level must not exceed this noise level.
5.2.14
According to the approved Yuen Long Outline Zoning Plan (OZP)
No. S/YL/23, the proposed DWF pumping station is located within a “Residential
(Group E)1” (“R(E)1”) zone. Assessment
point, NSR3, was included in the operational noise impact assessment to
represent the nearest NSR to the proposed DWF pumping station within 250m
distance from the boundary of the Yuen Long Industrial Estate, zoned as “Other
Specified Uses” annotated “Industrial Estate” (“OU(IE)”) in the OZP. Representative NSRs that may potentially be
affected by the operation of the proposed DWF pumping station are shown in Figure 5.2.
5.2.15
As the proposed DWF pumping station will operate 24 hours a
day, the ANL-5 during night-time, for which is most stringent, will be adopted.
With reference to the baseline noise level described in Section 5.3.2, the
noise criteria of the fixed plant noise under EIAO for NSRs with different ASRs
are presented in Table 5.5.
Table 5.5 Noise Criteria for Fixed Plant Noise under EIAO
|
ASR |
ANL-5,
dB(A) |
|
Baseline
Noise Levels, dB(A) |
Fixed
Plant Noise Criteria, dB(A) |
|
A |
45 |
|
48 |
45 |
|
B |
50 |
|
48 |
48 |
|
C |
55 |
|
48 |
48 |
5.2.16
In any event, the noise criterion
employed in this Report is for an
indicative operational noise assessment only.
It should be noted that 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 Report shall bind the Noise Control Authority in the
context of law enforcement against any fixed noise source being assessed.
5.3.1
The existing ambient noise levels are mainly generated by
traffic along Castle Peak Road, Yuen Long Highway, West Rail Line between Long
Ping and Yuen Long and other local roads.
Background noise sources also include existing processing plants and
factories located in the nearby Yuen Long Industrial Estate (YLIE) and Tung Tau
Industrial Area (TTIA).
5.3.2
Background noise measurements to investigate the prevailing
noise levels at the representative NSR near the proposed DWF pumping station
have been undertaken from 17 January 2019 to 18 January 2019. The measurement location is indicated in Figure
5.2. The measured minimum background
noise level during night-time period is lower than that of the ANL-5 levels for
ASR B. The measured background noise levels are summarized in Table 5.6. The
detailed baseline noise measurement data and record are provided in Annex 5A.
Table 5.6 Measured Baseline Noise Levels
|
Measurement
Location |
Time Periods |
Measured Noise Levels,
Leq, 30min dB(A)* |
|
|
Shan Pui Chung Hau Tsuen |
Day-time: |
07:00 to 23:00 hrs |
55 – 65 |
|
|
Night-time: |
23:00 to 07:00 hrs |
48 - 59 |
Note: *All extraneous noise data was neglected for determination of baseline noise level.
5.4.1
Representative noise sensitive receivers (NSRs) were identified
according to the criteria set out in the EIAO-TM. In accordance with the
requirements stated in Clause 3.4.2.2 of
the EIA Study Brief, the Study Area
for the noise impact assessment covered an area of 300 m from the boundary of
the Project Site. Only the first layer of NSRs has been
identified for assessment as it would provide acoustic shielding to those receivers
at further distance behind.
5.4.2
The 300 m study area is within the Yuen Long OZP No. S/YL/23
and Nam Sang Wai OZP No. S/YL-NSW/8. The relevant OZPs, Outline Development
Plans and Layout Plans and the land use and development applications approved
by the Town Planning Board have been reviewed. Site survey has also been
conducted for identifying NSRs. A total of 25 existing and one planned
representative NSRs have been identified based on the site survey and review of
the land use plans. The identified representative NSRs are shown in Table 5.7 and their locations are
indicated in Figure 5.1 a–d. The photos of the representative NSRs are presented in Annex 5B.
In order to assess the worst-case scenario, the lowest floor of the NSRs have
been selected as the assessment point.
Table 5.7 Representative Noise Sensitive Receivers (NSRs)
|
NSR
ID |
Description |
Type
of Usage |
No.
of Floors |
Floor
of selected assessment point |
Horizontal
Distance to the Nearest Site Boundary (m) |
|
NSR01 |
Tung Tau Wai San Tsuen |
Residential |
2 – 3 |
G |
12 |
|
NSR02 |
Shan Pui Chung Hau Tsuen |
Residential |
1 – 2 |
G |
10 |
|
NSR03 |
Twin Regency |
Residential |
22 |
G |
8 |
|
NSR04 |
Yuk Yat Garden |
Residential |
3 |
G |
21 |
|
NSR05 |
Wang Fu Court |
Residential |
13 |
G |
5 |
|
NSR06 |
Yeung Uk San Tsuen |
Residential |
3 |
G |
28 |
|
NSR07 |
Yuen Long Long Ping Estate
Wai Chow School |
School |
6 |
G |
39 |
|
NSR08 |
The Spectra |
Residential |
25 |
G |
11 |
|
NSR09 |
Tai Kiu Tsuen |
Residential |
1 – 4 |
G |
8 |
|
NSR10 |
Fuk Yip Building |
Residential |
5 |
G |
1 |
|
NSR11 |
Yuen Fat House |
Residential |
5 |
G |
1 |
|
NSR12 |
Healey Building |
Residential |
24 |
G |
2 |
|
NSR13 |
Wah Shing Mansion |
Residential |
5 |
G |
6 |
|
NSR14 |
CCC Chun Kwong Primary
School |
School |
5 |
G |
1 |
|
NSR15 |
Tse King House |
Residential |
6 |
G |
2 |
|
NSR16 |
On Ning Building |
Residential |
11 |
G |
1 |
|
NSR17 |
Ho Wang Building |
Residential |
20 |
G |
1 |
|
NSR18 |
Caritas Yuen Long Chan Chun
Ha Secondary School |
School |
6 |
G |
4 |
|
NSR19 |
Sun Fai Court |
Residential |
2 – 3 |
G |
2 |
|
NSR20 |
Ma Tin Tsuen - Kung Um Road |
Residential |
3 |
G |
2 |
|
NSR21 |
Yuen Long Villa |
Residential |
3 |
G |
3 |
|
NSR22 |
Lung Tin Tsuen |
Residential |
3 |
G |
31 |
|
NSR23 |
Wang Chau Lam Uk Tsuen |
Residential |
3 |
G |
38 |
|
NSR24 |
Wang Chau Tung Tau Wai |
Residential |
3 |
G |
64 |
|
NSR25 |
Hong Kong School of Motoring
- Yuen Long Road Safety Centre |
School |
1 |
G |
188 |
|
R1 |
Sol City (Planned) |
Residential |
19 – 29 |
G |
8 |
5.5.1
The Project includes the construction of the DWF interceptors
and u-channels/pipes, DWF pumping station, and rising mains. The major construction activities for the
above works will include ground breaking, excavation, pipe laying, backfilling
works and final re-instatement by in-situ
concreting. Potential sources of noise impacts
during the construction phase of the Project will mainly arise from powered mechanical equipment (PME) operating
at the construction work sites. Based on
the current construction design, percussive piling and blasting are not
required. The details of project construction are given in Section 2.3.
5.5.2
Based on the current programme, no construction works will be
required during the restricted hours under the NCO. The normal working hours of the construction
of the Project will be between 0700 and 1900 hours from Monday to Saturday
(except general holidays). Should
evening and night works between 1900 and 0700 hours or on public holidays
(including Sundays) be required, the Contractor will submit a CNP application
which will be assessed by the Noise Control Authority.
5.5.3
During the operation phase, only minor maintenance works such
as regular clearance of debris inside the YLTN and repair of damages to the channel
bed and sides are expected. Thus, it is
anticipated that the potential noise impacts arising from these maintenance
works would be minimal.
5.5.4
Noise will be generated from fixed plant sources during
operation, i.e. the DWF pumping station proposed to be located near the Yuen
Long Kau Hui Sewage Pumping Station. All
equipment will be accommodated inside the plant rooms and hence fully
enclosed. Operational noise from the
pumping station is assumed to be emitted through the louvres. The fixed plant items for the proposed DWF
pumping station is given below which have been agreed with the project
proponent and relevant DSD divisions:
DWF pumping station:
·
2 nos. of mechanical screens;
·
2 nos. of submersible pumps; and
·
2 nos. of exhaust fans (1 for deodourizer and 1 for general
ventilation).
5.5.5
In addition to the above, extra set of mechanical screen,
submersible pump and fan for ventilation will be provided as standby. As they will only be operated when normal
operating items are not working, the maximum no. of items in operation will be
2 nos. of each item.
5.6.1
The construction noise impact assessment was undertaken in
accordance with the EIAO-TM and the
procedures outlined in the GW-TM issued
under the NCO. The assessment methodology is summarised as
follows:
·
Identify the representative NSRs that may
be affected by the construction of the Project;
·
Determine the plant items for
corresponding construction activities, based on the agreed plant inventory;
·
Assign sound power levels (SWLs) to the
PME proposed based on the GW-TM and list of SWLs of other commonly used
PME([1]);
·
Calculate the correction factors based on
the distance between the NSRs and the notional noise source positions of
different works areas;
·
Apply corrections in the calculations,
such as potential screening effects and acoustic reflection, if any; and
·
Predict the construction noise levels at
NSRs in the absence of any mitigation measures.
5.6.2
The construction noise assessment was undertaken based on the
proposed construction works programme and plant inventory, and appropriate utilisation rates of the
PME items (Annex 5C). Same utilization rates have been used for the
same type of PME among all works areas. The plant inventory (including the type
of equipment, their quantity and utilization rate) in Annex 5C-2 have been reviewed
by the Project Engineer and confirmed to be appropriate and practicable for
completing the works within the proposed construction programme.
5.6.3
The proposed methods for the
construction of the Project are common in Hong Kong and the PMEs proposed are
available in the Hong Kong market.
5.6.4
For the purpose of the construction noise assessment, the
entire construction site was divided into nine separate works areas (one for
rising main, one for DWF pumping station, seven for DWFI system), with each works
area expected to be operated for 5 to 14 months as shown in the construction
programme in Annex 5C-1. The nine separate works areas are presented
in Figure 5.1a-e.
5.6.5
The total SWL associated with each construction activity for
the corresponding works areas was established. The potential noise impacts at NSRs
were subsequently evaluated by comparing the predicted noise levels with the EIAO-TM day-time construction noise
limits (Leq, 30min dB(A)).
5.6.6
The methodology for the fixed plant noise impact assessment
follows the procedures outlined in the IND-TM. The methodology is summarised as follows:
·
Identify types of equipment and the number
of equipment (if available);
·
Assign sound power levels (SWLs) to the
proposed equipment with
reference to EIA studies in similar nature, noise data from supplier, Good Practices on Pumping System Noise
Control (GP-PS) and Good Practices on
Ventilation System Noise Control (GP-VS);
·
Identify representative NSRs that may be
affected by the fixed plant;
·
Calculate the correction factors, using a
conservative approach, based on the horizontal distance between the NSRs and
the fixed plant sources;
·
Calculate the corrected noise levels after
taking into account other corrections such as potential screening effects, if
any, by adopting standard acoustics principles; and
·
Present the results in terms of Leq,
30min dB(A), as specified in the IND-TM.
5.6.7
The DWF pumping station will operate 24 hours a day as confirmed
by the project proponent. A flow meter with automatic metering is required to
ensure that the total flow through the pipe will not exceed the design capacity
of 18,000m3/day. Once the total flow exceeds 18,000m3/day,
the system will shut down the inlet penstock to avoid overloading of YLSTW. The operation
of the proposed DWF pumping station have been commented and agreed with the
project proponent and relevant DSD divisions in the submission of Design
Memorandum.
5.6.8
Distance attenuation was taken into account in the noise calculations
where the direct distance between the nearest louvre and each of the
representative NSRs in the vicinity was estimated. All the mechanical screens and submersible
pumps will be totally enclosed inside building structure. The exhaust fans will be fitted with acoustic
louvre/silencer. Barrier correction was
also considered in which a noise reduction of 10 dB(A) was applied to the fixed
plant depending on the line of sight of the representative NSRs. A positive 3 dB(A) correction was included in
the calculations to predict the noise levels at the NSRs due to façade effect. In
the Environmental Review Report for application of Variation of Environmental Permit
(VEP) for Yuen Long Kau Hui No. 2 Sewage
Pumping Station with
Environmental Permit (VEP-455/2014), the tonality correction of 0–3 dB(A) for four existing pumping
stations nearby has been derived based on noise measurement. With reference to
the report, a positive 3 dB(A) tonality correction was included in the noise
calculation for the DWF pumping station.
5.6.9
No corrections have been applied for intermittency or
impulsiveness as such noise characteristics are not expected. If the noise shows any of these
characteristics during the operation of the plant, the noise limit should be reduced
in accordance with the recommendation indicated in Section 3.3 of IND-TM.
5.6.10 There would be some limitations such as the accuracy of the prediction for future conditions (e.g. plant inventory for the proposed construction works and fixed plant for future operation).
5.6.11
During
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. For
operation noise assessment, being the worst-case scenario, all items of
equipment have been assumed to operate simultaneously during the operation
period. For determining the distance correction factors, the horizontal
distances between the noise source positions and the NSRs were used for
representing the worst level of the representative NSRs for both construction
and operation phases.
5.7.1
The predicted façade noise levels during daytime period due
to the construction activities are calculated in accordance with the
methodology described in GW-TM. The results are summarised in Table 5.8 with details of the noise calculations given in Annex 5C-2.
Table 5.8 Predicted Construction Noise Levels (Without Mitigation Measures)
|
NSR No. |
Description |
Predicted
Noise Level, dB(A) |
Noise Criteria, Leq, 30min, dB(A) |
|
NSR01 |
Tung Tau Wai San Tsuen |
79 |
75 |
|
NSR02 |
Shan Pui Chung Hau Tsuen |
82 |
75 |
|
NSR03 |
Twin Regency |
89 |
75 |
|
NSR04 |
Yuk Yat Garden |
75 |
75 |
|
NSR05 |
Wang Fu Court |
75 |
75 |
|
NSR06 |
Yeung Uk San Tsuen |
76 |
75 |
|
NSR07 |
Yuen Long Long Ping Estate
Wai Chow School |
72 |
70/65
(a) |
|
NSR08 |
The Spectra |
77 |
75 |
|
NSR09 |
Tai Kiu Tsuen |
86 |
75 |
|
NSR10 |
Fuk Yip Building |
89 |
75 |
|
NSR11 |
Yuen Fat House |
89 |
75 |
|
NSR12 |
Healey Building |
83 |
75 |
|
NSR13 |
Wah Shing Mansion |
85 |
75 |
|
NSR14 |
CCC Chun Kwong Primary School |
85 |
70/65
(a) |
|
NSR15 |
Tse King House |
80 |
75 |
|
NSR16 |
On Ning Building |
82 |
75 |
|
NSR17 |
Ho Wang Building |
89 |
75 |
|
NSR18 |
Caritas Yuen Long Chan Chun
Ha Secondary School |
80 |
70/65
(a) |
|
NSR19 |
Sun Fai Court |
89 |
75 |
|
NSR20 |
Ma Tin Tsuen - Kung Um Road |
87 |
75 |
|
NSR21 |
Yuen Long Villa |
88 |
75 |
|
NSR22 |
Lung Tin Tsuen |
73 |
75 |
|
NSR23 |
Wang Chau Lam Uk Tsuen |
76 |
75 |
|
NSR24 |
Wang Chau Tung Tau Wai |
74 |
75 |
|
NSR25 |
Hong Kong School of Motoring
- Yuen Long Road Safety Centre |
66 |
70/65
(a) |
|
R1 |
Sol City (Planned) |
85 |
75 |
|
Notes: (a)
70/65 denotes noise criteria during normal
school days / examination period, respectively. |
|||
5.7.2
Results indicate that the construction noise levels at most
of the representative NSRs exceeded the EIAO-TM
noise criteria in day-time during the course of the construction period. Therefore, mitigation measures will be
required.
5.7.3
The predicted fixed plant noise levels at the representative
NSRs due to the operation of the proposed DWF pumping station are summarised in
Table 5.9.
The predicted noise levels at all the representative NSRs comply with the
noise criteria under EIAO as shown in Section
5.2.15. Details of the calculation
are given in Annex 5C-3.
Table 5.9 Predicted Fixed Plant
Noise Levels due to the Proposed DWF Pumping Station
|
NSR |
Description |
Predicted Fixed Plant Noise Level, dB(A) |
ASR |
Applicable Noise Limit, dB(A) |
Exceedance |
|
NSR01 |
Tung Tau Wai San Tsuen |
33 |
B |
48 |
No exceedance |
|
NSR02 |
Shan Pui Chung Hau Tsuen |
33 |
B |
48 |
No exceedance |
|
NSR03 |
Twin Regency |
45 |
B |
48 |
No exceedance |
|
NSR04 |
Yuk Yat Garden |
27 |
A |
45 |
No exceedance |
|
NSR05 |
Wang Fu Court |
27 |
A |
45 |
No exceedance |
|
NSR23 |
Wang Chau Lam Uk Tsuen |
31 |
A |
45 |
No exceedance |
|
NSR24 |
Wang Chau Tung Tau Wai |
30 |
B |
48 |
No exceedance |
5.7.4
The operation noise of the proposed DWF pumping station alone
shall comply with the criteria under the EIAO. The specified SWLs presented in Annex 5C-3 should be included
in the tender specification. The
suppliers of equipment should guarantee the compliance of EIAO-TM noise
criteria, with the characteristics of tonality, impulsiveness and intermittency
accounted for, by providing certificate of measurement and verify the SWL during
testing and commissioning in accordance with international standard procedures. If necessary, the suppliers should apply
attenuation measures (e.g. use of silencers) to achieve the guaranteed noise
levels during the detailed design stage.
5.8.1
In view of the predicted noise exceedances during the
construction of the Project, the following mitigation measures have been
considered:
·
Good construction site practice;
·
Use of quiet PME;
·
Adoption of movable noise barriers;
·
Use of noise insulation sheet;
·
Adoption of fixed temporary noise barriers; and
·
Scheduling of PME / construction activities.
Good Construction Site Practice
5.8.2
Good construction site practice and noise management can
considerably reduce the potential noise impact of the construction activities
on nearby NSRs. The noise benefits of these practices can vary according
to specific site conditions and operations. Since the effect of the good
construction site practices could not be quantified, the mitigated noise levels
calculated in the subsequent sections have not taken account of this
effect. The following site practices should be followed during the construction
of the Project:
·
Only well-maintained plant should be
operated on-site and plant should be serviced regularly during the construction
phase;
·
Silencers or mufflers on construction
equipment should be utilised and should be properly maintained during the
construction phase;
·
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, wherever possible, be orientated so that the noise is
directed away from the nearby NSRs; and
·
Material stockpiles and other structures should
be effectively utilised, wherever practicable, in screening noise from on-site
construction activities.
Use of Quiet PME
5.8.3
The use of quiet PME is considered to be a practicable means
to mitigate the construction noise impact. Quiet PME is defined as a PME
having actual SWL lower than the value specified in the GW-TM. The total SWL of all plant items to be used on-site at
each works area will be specified so that flexibility is allowed for the
Contractor to select plant items to suit the construction needs. The Contractor
shall select plant items with total SWL equal to or lower than the total SWL specified
in the plant inventory in Annex 5C-7 in order to meet the relevant
noise criteria. Quiet PME that have been adopted in the assessment are summarised
in Table 5.10.
Table 5.10 Sound Power Level of Quiet PME
|
PME |
EPD QPME Reference(a)(b) |
Sound Power
Level (dB(A)) |
|
Hand-held percussive breaker |
EPD-07425 |
103 |
|
Generator |
EPD-08020 |
91 |
|
Dump truck, 5.5 tonne <
gross vehicle weight ≤ 38 tonne |
EPD/PME/38 |
105 |
|
Excavator, mini-robot
mounted |
EPD/PME/13 |
94 |
|
Crane, mobile |
EPD-07994 |
101 |
|
Note: (a)
“Sound power levels of other commonly used
PME” prepared by the Noise Control Authority (http://www.epd.gov.hk/epd/english/application_for_licences/guidance/files/OtherSWLe.pdf) (b)
Quality powered
mechanical equipment (https://www.epd.gov.hk/cgi-bin/npg/qpme/search_gen.pl?lang=eng&st=sim&valid=Y) |
||
5.8.4
The use of noise barriers will be an effective means to
mitigate the noise impact arising from the construction works, particularly for
low-rise NSRs. With reference to EIAO
Guidance Note No. 9/2010 Preparation of Construction Noise Assessment Under the
Environmental Impact Assessment Ordinance (EIAO GN No. 9/2010), the use of
movable barrier for certain PME could generally provide a 5 dB(A) reduction for
movable PME and 10 dB(A) for stationary PME.
The schematic configuration of movable noise barrier is presented in Annex
5C-4.
5.8.5
Noise insulating sheet would be adopted for PME such as drill
rig (Annex 5C-5). The noise insulating sheet should be deployed
such that there would be no opening or gaps on the joints. With reference to the approved EIA Report for West
Island Line (WIL) (Register No.: AEIAR-126/2008 approved on 23 Dec 2008)
and MTRC Contract C4420 Tsim Sha Tsui
Modification Noise Assessment Report for VEP (July 2003), a reduction of
over 10 dB(A) could be achieved with the use of the noise insulating sheet. For a conservative assessment, a noise
reduction of 10 dB(A) for the PME with deployment of noise insulating sheet was
assumed in this assessment.
5.8.6
In
view of the close proximity between NSRs and the works areas for construction
of DWFI system, fixed temporary noise barriers will be deployed at the working
section as far as practicable. Fixed
temporary noise barriers of 3m in height with skid footing should be used
and located within a few metres of stationary plant and mobile plant such that
the line of sight to the NSR is blocked by the barriers. The length of
the barrier should be at least five times greater than its height. The noise barrier
material should have a sufficient surface density of at least 7 kg/m2
and have no openings or gaps. Reference has been made to EIAO GN No. 9/2010; it
is anticipated that the major noise source of movable PMEs, such as breaker,
water pump, concrete lorry mixer and excavator, will be located within the
nullah at a level lower than the top of the proposed fixed temporary noise
barrier, and therefore these barriers could produce at least a 5 dB(A) noise
reduction. A sample sectional drawing showing the location of proposed temporary
noise barrier and NSRs located along both sides of the nullah are shown in Annex 5C-6.
5.8.7
The construction activities will be planned and carried out
in sequence rather than simultaneously at each location. Instead of being
operated simultaneously, the PMEs would be grouped (see Annex 5C-7) and only one group of PME would be operated at any one
time for each construction activity for reducing the construction noise impact.
5.8.8
It is considered practical to specify the quiet PME and noise
mitigation measures described in Section
5.8.3 in the contract document to mitigate the construction noise impact.
5.8.9
With the implementation of the use of quiet PME and movable
noise barriers for various construction activities, the mitigated noise levels
at the representative NSRs were calculated and the results are summarised in Table 5.11 with details of the calculations
given in Annex 5C-7. The results indicated that the predicted
façade noise levels are in the range of 58 to 74 dB(A) and 51 to 70 dB(A) at
residential NSRs and educational NSRs, respectively.
5.8.10
The maximum predicted construction noise level at NSR14 would
be 70 dB(A). This comply with the noise criteria of 70dB(A) during normal
school days but exceed the criteria of 65 dB(A) during examination period. However,
this potential exceedance can be avoided with special arrangement below. For
NSR18, the maximum predicted construction noise level would be 65 dB(A) and
meet the noise criteria during examination period. However, in order to
minimize the potential cumulative impact with concurrent projects discussed in
Section 5.9, the following special arrangement during examination period is
recommended:
·
The contractor could liaise with the
school management about the arrangements during examination weeks.
·
PMEs shall not be used at the closest
works areas (i.e. Section B1 for NSR14 and Section A3 for NSR18) during the examination
period.
5.8.11
With the above arrangements in place, the predicted maximum
construction noise level at both NSR 14 and NSR 18 would be 55 dB(A). As there would be no exceedance of the noise
criterion during examination period, no unacceptable impact is expected at the
NSRs at that particular period.
5.8.12
Table 5.11 shows that the predicted
construction noise levels at all NSRs comply with the noise criteria during the
daytime period, therefore, no unacceptable noise impact is expected to arise
from the construction activities to be carried out within the works areas.
Table 5.11 Predicted Construction Noise Levels (With Mitigation Measures)
|
NSR No. |
Description |
Predicted Noise Level,
dB(A) |
Noise
Criteria, Leq, 30min, dB(A) |
|
NSR01 |
Tung Tau Wai San Tsuen |
63 |
75 |
|
NSR02 |
Shan Pui Chung Hau Tsuen |
67 |
75 |
|
NSR03 |
Twin Regency |
74 |
75 |
|
NSR04 |
Yuk Yat Garden |
60 |
75 |
|
NSR05 |
Wang Fu Court |
60 |
75 |
|
NSR06 |
Yeung Uk San Tsuen |
60 |
75 |
|
NSR07 |
Yuen Long Long Ping Estate
Wai Chow School |
57 |
70/65
(a) |
|
NSR08 |
The Spectra |
61 |
75 |
|
NSR09 |
Tai Kiu Tsuen |
71 |
75 |
|
NSR10 |
Fuk Yip Building |
73 |
75 |
|
NSR11 |
Yuen Fat House |
74 |
75 |
|
NSR12 |
Healey Building |
68 |
75 |
|
NSR13 |
Wah Shing Mansion |
70 |
75 |
|
NSR14 |
CCC Chun Kwong Primary
School |
70
(normal school days) / 55 (examination period) |
70/65
(a)(b) |
|
NSR15 |
Tse King House |
65 |
75 |
|
NSR16 |
On Ning Building |
67 |
75 |
|
NSR17 |
Ho Wang Building |
74 |
75 |
|
NSR18 |
Caritas Yuen Long Chan Chun
Ha Secondary School |
65
(normal school days) / 55 (examination period) |
70/65
(a) |
|
NSR19 |
Sun Fai Court |
74 |
75 |
|
NSR20 |
Ma Tin Tsuen - Kung Um Road |
72 |
75 |
|
NSR21 |
Yuen Long Villa |
73 |
75 |
|
NSR22 |
Lung Tin Tsuen |
58 |
75 |
|
NSR23 |
Wang Chau Lam Uk Tsuen |
60 |
75 |
|
NSR24 |
Wang Chau Tung Tau Wai |
59 |
75 |
|
NSR25 |
Hong Kong School of Motoring
- Yuen Long Road Safety Centre |
51 |
70/65
(a) |
|
R1 |
Sol City (Planned) |
70 |
75 |
|
Notes: (a)
70/65 denotes noise criteria during normal
school days / examination period, respectively. (b)
With the special construction arrangements
specified in Section 5.8.10 in place, no exceedance of the noise criterion
during examination period is anticipated |
|||
5.8.13
While no unacceptable noise impact is expected due to the
operation of fixed plant items, it is still recommended that the following
measures be implemented as far as practicable to minimise the potential impact:
·
Quieter plant should be chosen as far as
practical;
·
Include noise levels specification when
ordering new plant items;
·
All openings, including louvres for
ventilation and machine room doors should be oriented away from the NSRs as far
as practicable;
·
Silencers, acoustic louvres or acoustic
doors should be used where necessary; and
·
Develop and implement a regularly
scheduled plant maintenance programme so that plant items are properly operated
and serviced. The programme should be
implemented by properly trained personnel.
5.8.14 Testing and commissioning of the proposed DWF pumping station would be carried out prior to operation. Noise monitoring would be carried out by the Contractor to ensure fixed noise sources impact would comply with the relevant noise standards.
Assessment of Side Effects and Constraints
5.8.15
In accordance with the requirements stated in Clause 6 in Appendix B of the EIA Study Brief, no side effects and
constraints due to the inclusion of the recommended mitigation measures have
been identified.
Construction
Phase
5.9.1
There
are three concurrent projects potentially causing cumulative noise impacts.
They are:
·
Yuen Long Barrage Scheme;
·
Elevated Pedestrian
Corridor in Yuen Long Town Connecting with Long Ping Station; and
·
Housing Sites in Yuen
Long South.
Yuen Long Barrage Scheme (YLBS)
5.9.2
With
reference to the Project Profile of YLBS, the only works within 300m area from
the most of the NSRs, except NSR 25, identified for the Project (Improvement of
YLTN) is nullah revitalization. With consultation from DSD, the nullah
revitalization will be carried out by Barrage Scheme after the construction
works of Improvement of YLTN. For NSR 25, the maximum predicted mitigated
construction noise levels from the YLTN Project is 51 dB(A). No unacceptable
cumulative noise impact is anticipated.
Housing Sites in Yuen Long South
5.9.3
According
to the EIA report of the housing development, no unacceptable noise impact is
anticipated by good site practices, use of noise barrier, “quiet” plant and
working method. There is no overlap of the project boundary of the housing development
and YLTN Project. The NSR 22 “Lung Tin Tsuen” would be the closest NSR to the
housing development and the maximum predicted mitigated noise level from the
YLTN Project is 58 dB(A). No unacceptable cumulative noise impact is
anticipated.
Elevated Pedestrian Corridor in Yuen Long
Town Connecting with Long Ping Station (EPC)
5.9.4
With
consultation from HyD, the project is tentatively scheduled to commence in first
quarter of 2020 for completion in first quarter of 2025. Compared with the
implementation programme in the EIA report, the expected commencement date was first
quarter of 2018. In view of it, the predicted construction noise levels (with
mitigation) in Appendix 5.8 of the EIA report (AEIAR-200/2016) is applied with
adjustment of 2-year forward. The predicted cumulative construction noise
levels are summarized in Table 5.12. The detailed calculation is presented
in Annex 5C-8.
Table 5.12 Predicted Cumulative Construction Noise Levels
|
NSR |
Description |
Max. Predicted Cumulative CNL, dB(A) |
Noise Criteria Leq, 30min, dB(A) |
Exceedance |
|
NSR09 |
Tai Kiu Tsuen |
73 |
75 |
No |
|
NSR12 |
Healey Building |
74 |
75 |
No |
|
NSR14 |
CCC Chun Kwong Primary
School |
70
(normal school days) / 68 (examination period) |
70/65 (a) |
Yes (b) |
|
NSR15 |
Tse King House |
72 |
75 |
No |
|
NSR16 |
On Ning Building |
69 |
75 |
No |
|
NSR17 |
Ho Wang Building |
74 |
75 |
No |
|
NSR18 |
Caritas Yuen Long Chan Chun
Ha Secondary School |
66
(normal school days) / 58 (examination period) |
70/65 (a) |
No |
|
Notes: (a)
70/65 denotes noise criteria during normal
school days / examination period, respectively. (b)
The construction noise
level during examination period due to the current project alone is only
55dB(A) which is 10 dB(A) below the criteria of 65dB(A). The exceedance
of cumulative noise is due to the EPC project only. The EIA report of
the EPC project also recommended special construction arrangements to avoid
this potential exceedance. |
||||
5.9.5
The
predicted cumulative CNL at NSRs will comply with noise criteria except for
NSR14. The maximum predicted cumulative CNL at NSR14 is 68 dB(A) during the
examination period which exceeds the noise criteria of 65 dB(A). According to
the approved EIA report of the EPC project (AEIAR-200/2016), the predicted CNLs
at NSR14 due to the EPC project is 68 dB(A) during examination period which
already exceeds the criteria of 65 dB(A). As the predicted mitigated CNL at
NSR14 due to the YLTN Project is 55 dB(A) during examination period which is 10
dB(A) below the criteria of 65 dB(A), the potential contribution from the YLTN
Project to the cumulative impacts to the NSR is considered as negligible. According
to the approved EIA Report of the EPC project, the potential exceedance would
be avoided by special construction arrangement during examination periods. As
such, no unacceptable cumulative noise impact is anticipated.
Operation
Phase
5.9.6
There are existing DSD pumping facilities located in
approximately 90m to the north-east of the proposed DWF pumping station. Cumulative noise impact from the existing pumping
facilities and the proposed DWF pumping station has been taken into account in
this assessment. Reference has been made
to the approved Environmental Review Report for application of VEP for Yuen Long Kau Hui No.
2 Sewage Pumping Station with Environmental Permit (VEP-455/2014) issued by EPD in December
2014 for the noise data of the existing pumping facilities. A figure showing the locations of the
existing pump facilities, including Yuen Long LFPS, Yuen Long Kau Hui
Floodwater Pumping Station, Yuen Long Kau Hui Sewage Pumping Station and Yuen
Long Kau Hui No. 2 Sewage Pumping Station, is given in Annex 5C-9. It is noted from the Environmental
Review Report that the LFPS and the Kau Hui Floodwater Pumping Station will not
be operated simultaneously. The pumping station with higher noise level and
closer to the respective NSRs (i.e. LFPS) has been included in the cumulative
impact assessment.
5.9.7
The cumulative noise level of the proposed pumping station
together with the existing pumping stations shall comply with the noise criteria
under the NCO. The cumulative noise levels with the operation of the existing pumping
stations are summarised in Table 5.13.
The predicted cumulative noise levels at all the representative NSRs
comply with the day-time and night-time noise criteria as shown in Section 5.2.11. Details of the calculation are given in Annex 5C-10.
Table 5.13 Predicted Cumulative Fixed Plant Noise Levels
|
NSR |
Description |
Predicted Cumulative Fixed Plant Noise Level, dB(A) |
ASR |
Applicable Noise Limit, dB(A) |
Exceedance |
|
NSR
1 |
Tung
Tau Wai San Tsuen |
33 |
B |
55 |
No exceedance |
|
NSR
2 |
Shan
Pui Chung Hau Tsuen |
39 |
B |
55 |
No exceedance |
|
NSR
3 |
Twin
Regency |
46 |
B |
55 |
No exceedance |
|
NSR
4 |
Yuk
Yat Garden |
27 |
A |
50 |
No exceedance |
|
NSR
5 |
Wang
Fu Court |
28 |
A |
50 |
No exceedance |
|
NSR
23 |
Wang
Chau Lam Uk Tsuen |
32 |
A |
50 |
No exceedance |
|
NSR24 |
Wang
Chau Tung Tau Wai |
31 |
B |
55 |
No exceedance |
Construction Phase
5.10.1
With the implementation of practical noise mitigation
measures, including the use of quiet PME, movable noise barriers, noise
insulation sheet and scheduling of construction activities, it is predicted
that there is no exceedance of the daytime construction noise criteria at all
NSRs. Therefore, unacceptable residual
impact is not anticipated.
Operation Phase
5.10.2
Both the predicted noise levels due to the operation of the
proposed DWF pumping station and the cumulative noise levels with the operation
of the existing pumping stations at all the representative NSRs comply with the
day-time and night-time noise criteria.
Thus, unacceptable residual impacts are not anticipated from the
operation of the Project provided that the appropriate contract specifications
and noise abatement measures as mentioned in Section 5.8 are incorporated in the Detailed Design.
5.11.1
The recommended mitigation measures, monitoring procedures
and locations are presented in detail in the Environmental Monitoring and Audit (EM&A) Manual. This will facilitate
the contractor to have early warning and undertake the necessary actions to
reduce noise emissions at specific areas.
The effectiveness of on-site control measures could also be evaluated through
the regular site audits. All the
recommended mitigation measures should be incorporated into the EM&A programme
for implementation during construction.
5.11.2 Noise
monitoring for the operation of DWF pumping station is considered
unnecessary during the operation phase.
Construction Phase
5.12.1
A construction noise assessment has been undertaken to
predict the noise levels at the representative NSRs due to the construction of
the Project. Practicable mitigation
measures, including good construction site practices, use of quiet construction
plant, movable noise barriers, noise insulation sheet and scheduling of
construction activities, have been recommended.
With the implementation of the recommended mitigation measures, the predicted
construction noise levels at all NSRs comply with the noise criteria during the daytime period. Therefore, no unacceptable noise impact is
expected to arise from the construction activities. Also, no unacceptable cumulative impact or
residual impact is anticipated. Regular
noise monitoring at NSRs as part of the EM&A programme during the
construction stage is recommended.
Operation Phase
5.12.2
Potential noise impact from the operation of the proposed DWF
pumping station has been assessed. The
predicted fixed plant noise levels at the representative NSRs due to the
operation of the proposed DWF pumping station and the cumulative noise levels
with the operation of the existing pumping stations comply with the day-time
and night-time noise criteria. No unacceptable
residual impact is anticipated. Attenuation
measures, if required, will be provided to the fixed plant items for achieving
the compliance of EIAO-TM noise criteria during the detailed design stage.
1)
DSD
(2014) – Environmental Review Report for application of Variation of Environmental
Permit (VEP) for “Yuen Long Kau Hui No. 2 Sewage Pumping Station” (VEP-455/2014).