4.1.1 This section presents an
assessment of the potential noise impact associated with the construction and
operation of the Project. The noise impact assessment was conducted in accordance
with the requirements set out under Section 3.4.4 of the EIA Study Brief. Recommendation for mitigation measures have
been made, where necessary and appropriate.
General
4.2.1
Noise impacts were assessed in accordance with the criteria and
methodology given in the Technical Memoranda (TMs) under the Noise Control
Ordinance (NCO), and Annexes 5 and 13 in the Technical Memorandum on
Environmental Impact Assessment Process (EIAO-TM).
Construction Noise
4.2.2 The
currently envisaged construction programme will not require any works using
powered mechanical equipment (PME) during restricted hours (i.e. the hours of
1900 to 0700 hours or at any time on a general holiday) nor percussive piling
works. On the above-mentioned basis, the criteria stipulated in Table 1B of
Annex 5 to the EIAO-TM, namely Leq (30 minutes) 75 dB(A) at the
façades of dwellings and 70 dB(A) at the façade of schools (65 dB(A) during
examinations), are relevant to the assessment of construction noise impacts.
Fixed Plant Noise
4.2.4
Fixed noise sources associated with the
Project would be controlled by the NCO and Technical
Memorandum for the Assessment of Noise from Places other than Domestic
Premises, Public Places or Construction Sites (IND-TM). The Acceptable
Noise Levels (ANL) is a function of the type of area within which the noise
sensitive receivers (NSRs) are located, and the degree of the effect on the
NSRs of influencing factors such as major roads and industrial areas. According
to the IND-TM, the ANLs for different Area Sensitivity Ratings (ASRs) are given
in Table 4.1.
Table 4.1 Acceptable Noise Levels (ANL)
|
Time Period
|
Area Sensitivity Rating (ASR)
|
|
A
|
B
|
C
|
|
Day
(0700 to 1900 hours)
|
60
|
65
|
70
|
|
Evening
(1900 to 2300 hours)
|
|
Night
(2300 to 0700 hours)
|
50
|
55
|
60
|
4.2.5
Since the Project is located in rural area
and no influencing factors (i.e. industrial activities or major roads) affect
the NSRs, an ASR of “A” has been assigned.
The EIAO-TM recommends that the level of the intruding noise at the
façade of the nearest sensitive use should be at least 5 dB(A) below
the appropriate ANL or, in the case of background noise being 5 dB(A)
lower than the ANL, the predicted noise level arising from the operation of the
proposed Project at the façade of the nearest sensitive use should not exceed
the background noise level. In this regard, noise measurement was undertaken in
the vicinity of the representative NSRs to study the prevailing noise level
(see Appendix
4.1). The assessment criteria for the proposed fixed noise sources of
the Project, as adopted in this EIA Study, are presented in Appendix
4.2.
4.3
Description
of the Environment
Existing Environment
4.3.1
The
project site is
located the existing
Lai Chi Yuen Cemetery at Mui Wo, Lantau Island. It falls within the
Lantau South Country Park. Some scattered village houses and Lai Chi Yuen Tsuen
are located to the north-west of the project site. The existing noise climate
of the Study Area was quiet and no major noise source was identified.
Noise Sensitive Receivers
4.3.2 The Study Area for the
noise assessment is defined by a distance of 300m from the boundary of the
Project and the works of the Project as shown in Figure 4.1. Representative NSRs were selected within the
Study Area according to the criteria set out in the EIAO-TM, through site
visits and a review of relevant land use plans including the Outline Zoning
Plans (OZP), Development Permission Area Plans, Outline Development Plans, Layout
Plans and other relevant published land use plans. According to OZP No.
S/SLC/19, no planned/committed noise sensitive developments were identified.
Noise sensitive uses in the close vicinity
of the project
site, as shown
in the OZP,
have been duly represented by the existing representative noise
sensitive receivers.
4.3.3 Figure 4.1 shows the locations of the
representative NSRs. Details of the
representative NSRs are presented in Table
4.2. Photographs of the
representative NSRs are shown in Appendix 4.3. These identified noise
assessment points were sent to Environmental Protection Department for
agreement prior to the quantitative assessment (see Appendix 4.4).
Table 4.2 Representative Noise Sensitive
Receivers
|
NSR ID
|
Description
|
Land Use
|
No. of storey
|
Distance between NSR and
nearest Project Boundary, m
|
|
N1
|
Scattered Village
Houses
|
Residential
|
1
|
209
|
|
N2
|
Lai Chi Yuen Tsuen
|
Residential
|
2-3
|
274
|
|
N3
|
Scattered Village
Houses
|
Residential
|
1
|
82
|
Construction
Phase
4.4.1 The potential source of noise
impact during construction phase of the Project would be the use of PME for
various construction activities. The Project would involve the major
construction activities, including slope works, substructure works,
superstructure works, fitting out works and landscape works. As confirmed
with the Project
Proponent, percussive piling
and blasting work
would not be required, and the works would be carried
out by general construction methods.
4.4.2 Generally, the
construction activities of the Project
would be carried
out in non-restricted hours (0700-1900 hours) during normal working
days. In case of any construction activities during restricted hours, it
is the Contractor’s responsibility to ensure compliance with the NCO and the relevant
TMs. The Contractor will be required to submit CNP application to the Noise
Control Authority and abide by any conditions stated in the CNP, should one be
issued.
4.4.3 Based on current available
information, no concurrent projects have been identified within 300m of the
project boundary. Hence, cumulative
construction noise impact due to the construction works of the Project and
other concurrent projects was not expected and assessed in this EIA Study.
Operational Phase
4.4.4 According to information
provided by the Project Proponent, the fixed plants to be installed for the new
niches include two water pumps and a joss paper burner. The joss paper burner
would be comprised of a water scrubber, an electrostatic precipitator and an
exhaust fan, which would generate noise during operation. In view of the buffer
distance of around 82m from the nearest village houses and the screening of
natural terrain around the site, the potential fixed plant noise impact arising
from the Project would not be insurmountable.
4.4.5 Since there is no fixed
noise source in the existing Lai Chi Yuen Cemetery, cumulative noise impact
arising from the operation of the existing cemetery and the Project would not
be expected.
Construction Noise
4.5.1 In accordance with the
EIAO-TM, the methodology outlined in the Technical
Memorandum on Noise from Construction Work other than Percussive Piling
(GW-TM) issued under the NCO was used for the construction noise assessment.
The general approach is summarized below:
•
Locate the NSRs which would most likely be
affected by noise from the construction work;
•
Determine the items of Powered Mechanical
Equipment (PME) for each discrete construction activity, based on available
information or agreed plant inventories;
•
Assign sound power levels (SWLs) to the
proposed PME according to the GW-TM or other sources;
•
Calculate distance attenuation and screening
effects to NSRs from notional noise source;
•
Predict construction noise levels at NSRs in
the absence of any mitigation measures; and
•
Include a 3 dB(A) façade correction to the
predicted noise levels in order to account for the façade effect at each NSR.
4.5.2 The assessment of
construction noise was undertaken based on standard acoustic principles. SWLs of
the equipment were taken from Table 3 of GW-TM.
Where no SWL was given in the GW-TM, reference was made to EPD’s Sound power levels of other commonly used
PME. Groups of PME were assigned for
various construction activities of the proposed Project. The proposed plant
inventory with appropriate on-time percentage for all items of PME for the
construction works of the Project is presented in Appendix 4.5. The Project Proponent has confirmed the
proposed plant inventories as being practical and adequate for completing the
works within the scheduled timeframe.
4.5.3 The assessment was
undertaken based on the assumption that all items of construction equipment
would be located at a notional noise source point for each phase of works and
that all items of equipment would be operating simultaneously.
Operational Fixed Plant Noise
SPL = Max. SWL – DC + FC –
BC
where
Sound Pressure Level (SPL) in dB(A)
Maximum Permissible Sound Power Level
(Max. SWL) in dB(A)
Distance Attenuation (DC) in dB(A)
= 20 log D + 8 [where D is distance in
metres]
Facade Correction (FC) in dB(A) = 3 dB(A)
Barrier Correction (BC) in dB(A)
4.5.5 Both the joss paper burner
and the water pumps should be free of characteristics of tonality,
impulsiveness and intermittency. A negative correction of 10 dB(A) was adopted
to include the screening effect of topographical features.
4.5.6 Noise impact was assessed
on the basis of the following conservative assumptions:
•
The distance is assumed to be the minimum
distance between the NSR and the Project boundary; and
•
All items of operational plant to be operated
simultaneously during the operation period.
Construction Phase
4.6.1
For normal daytime working hours, the predicted noise levels at the
representative NSRs would be in the range of 58 to 75 dB(A) in the absence of
mitigation measures. Exceedances of the construction noise criteria (Leq
(30 minutes) 75 dB(A) for residential
uses were not predicted and hence noise
mitigation measures would not be
required. Details of construction noise
calculations and results are presented in Appendix 4.6. A summary of the
unmitigated construction noise levels of the representative NSRs during normal
daytime working hours is shown in Table
4.3.
Table 4.3 Summary of Predicted Unmitigated
Construction Noise Levels at Representative Noise Sensitive Receivers during
Normal Daytime Working Hours
|
NSR ID
|
Description
|
Use
|
Predicted Noise
Level, dB(A)
|
Noise Criteria,
dB(A)
|
|
N1
|
Scattered Village
Houses
|
Residential
|
60
– 68
|
75
|
|
N2
|
Lai Chi Yuen Tsuen
|
Residential
|
58
– 65
|
75
|
|
N3
|
Scattered Village
Houses
|
Residential
|
68
– 75
|
75
|
4.6.2 According to Annex 13 of
the EIAO-TM, Lantau South Country Park
is a potential NSR. However, in view of the transient nature of visitors to the
Country Park, any potential construction noise impact on the visitors would not
be considered insurmountable and hence was not identified as a noise assessment
point in the assessment.
Operational Phase
4.6.3 The total maximum
permissible sound power levels (Max. SWL) of the water pumps and joss paper
burner at the extension area was determined by adopting the methodology
described in Section 4.5.4. The result is shown in Table 4.4 and detailed calculation is
presented in Appendix 4.7.
Table 4.4 Predicted Total Maximum Permissible
Sound Power Level of the Water Pumps and
Joss Paper Burner
|
NSR ID
|
Description
|
Noise Criteria
(daytime), dB(A) (1)
|
Max. SWL, dB(A)
|
|
N1
|
Scattered Village
Houses
|
41
|
94
|
|
N2
|
Lai Chi Yuen Tsuen
|
44
|
|
N3
|
Scattered Village
Houses
|
41
|
Notes:
(1) As the fixed plants would only operate from 8:30am to 5:30pm, only the
daytime noise criteria are considered in this assessment.
4.6.4 No adverse operational
noise impact would be expected arising from the water pumps and proposed joss
paper burner if they are designed to not exceed the Max. SWL. As confirmed by
the Project Proponent, the total Max. SWL as shown in Table 4.4 above could be achieved by incorporated with the sound
attenuators such as silencers and muffler, for reduction of the operation noise
emission levels so as to comply with relevant noise criteria.
4.6.5 According to Annex 13 of
the EIAO-TM, Lantau South Country Park
is also a potential noise sensitive receiver. Providing that the fixed plants
would be designed to not exceed the Max. SWL, operational noise impact to
Lantau South Country Park would be insignificant.
Construction Phase
4.7.1 Although no exceedance of
the construction noise criteria was predicted without mitigation measures, good
site practice listed below and the noise control requirements stated in EPD’s
"Recommended Pollution Control
Clauses for Construction Contracts” should be implemented to further
minimise the potential noise nuisance during construction phase.
• Only well-maintained plant to be operated on-site and plant should be
serviced regularly during construction works;
• Machines and plant that may be in intermittent use to 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 to direct noise away from the NSRs;
• Mobile plant should be sited as far away from NSRs as possible; and
• Material stockpiles and other structures to be effectively utilized,
where practicable, to screen noise from on-site construction activities.
Operational Phase
4.7.2 Since the predicted noise
levels at all representative NSRs would comply with the noise criteria, no
mitigation measure for the operation of the Project is required.
Construction Phase
4.8.1 No residual impact is
anticipated during construction of the Project.
Operational Phase
4.8.2 No residual impact is
anticipated during operation of the Project.
4.9.1 No construction noise
monitoring is considered necessary.
Regular site environmental audit during the construction phase of the
Project as specified in the separate EM&A Manual should be conducted to
ensure the good site practices are properly implemented.
4.9.2 No
adverse operational noise quality impact is anticipated. Operation noise monitoring
is not considered necessary.
4.10.1 This assessment has
predicted the construction noise impacts of the Project during normal daytime
working. The predicted unmitigated noise levels at representative NSRs would
range from 58 to 75 dB(A). The noise levels at all representative NSRs would
comply with the construction noise criterion of 75 dB(A).
The noise impact associated with the
operation of the Project was assessed. No adverse
operational noise quality impact on all representative NSRs would be
anticipated provided that the water pumps and joss paper burner would be designed to not exceed
the total Max. SWL of 94 dB(A).