4.1 Legislation, Standards and
Guidelines
4.2 Description of the Environment
4.3 Assessment Area and Noise Sensitive
Receivers
4.4 Construction Noise Impact Assessment
4.5 Operational Noise Impact Assessment
Figures
Figure 4.1 Locations of
Representative Noise Sensitive Receivers
Appendices
Appendix 4.1 Photos
of Representative Noise Sensitive Receivers
Appendix 4.2 Detailed
Plant Inventory
Appendix 4.3 Locations
of Workfronts
4.1
Legislation,
Standards and Guidelines
4.1.1
General
4.1.1.1
The
relevant legislation and associated guidance applicable to this Study for the
assessment of noise impact include:
·
Environmental
Impact Assessment Ordinance (EIAO) (Cap. 499), including Technical Memorandum
on Environmental Impact Assessment Process (TM-EIAO),
Annex 5 and Annex 13;
·
Noise
Control Ordinance (NCO) (Cap. 400);
·
Technical
Memorandum (TM) on Noise from Construction Work other than Percussive Piling
(TM-GW);
·
TM
on Noise from Percussive Piling (TM-PP);
·
TM
on Noise on Construction Work in Designated Areas (TM-DA); and
·
TM
on Noise from Places other than Domestic Premises, Public Places or Construction
Sites (TM-Places).
4.1.2
Construction
Noise
Construction Noise during Normal
Hours
4.1.2.1
NCO
provides the statutory framework for noise control in Hong Kong. Assessment
procedures and standards are set out in the respective TM promulgated under
NCO.
4.1.2.2
To
ensure a better environment, the TM-EIAO promulgated under the EIA Ordinance
has imposed more stringent criteria. For construction, there is no statutory
limit on daytime construction noise under NCO and related TMs. There is
statutory control on construction noise during daytime on general holidays
(including Sundays). Nevertheless, the
TM-EIAO stipulates criteria of 65-75dB(A) for daytime construction activities,
as shown in Table 4.1.
Table 4.1 Noise standards for daytime construction
activities
|
Uses |
Noise Standards[1], [2], Leq (30 mins) dB(A) |
|
0700 – 1900
hours on any day not being a Sunday or general holiday |
|
|
All domestic premises including temporary housing
accommodation |
75 |
|
Hotel and hostels |
75 |
|
Educational institutions
including kindergartens, nurseries and all others where unaided voice
communication is required |
70 65 (During examination) |
Notes:
[1] The
above standards apply to uses that rely on opened windows for ventilation.
[2] The above standards should be viewed as the maximum permissible
noise levels assessed at 1m from the external facade.
Construction Noise during Restricted
Hours
4.1.2.3
NCO
also provides statutory control on general construction works during restricted
hours (i.e. 1900 to 0700 hours (of the next day) from Monday to Saturday and at
any time on Sundays or public holidays).
The use of Powered Mechanical Equipment (PME) for construction works
during restricted hours would require a Construction Noise Permit (CNP). The
TM-GW details the procedures adopted by Environmental Protection Department
(EPD) for assessing such application. The granting of a CNP is subject to
conditions stated in the CNP and it may be revoked at any time for failure to
comply with the permit conditions.
4.1.2.4
In
addition to the general controls on the use of PME during restricted hours, the
use of Specified Powered Mechanical Equipment (SPME) and the undertaking of
Prescribed Construction Work (PCW) during the restricted hours in a designated
area are controlled by the TM-DA. Construction plant or equipment classified as
SPME under the TM-DA includes hand-held breakers, bulldozers, concrete lorry
mixers, dump trucks and vibratory pokers. The PCW includes the erection or
dismantling of formwork or scaffolding, hammering, loading, unloading or handling
of rubble, wooden boards, steel bars, wood or scaffolding material, and the
disposal of rubble through plastic chutes.
4.1.2.5
The
TM-DA details the procedures that should generally be adopted by the Noise
Control Authority for assessing the use of SPME during restricted hours and for
determining whether a CNP would be issued.
4.1.2.6
Maximum
noise levels from construction activities during restricted hours at affected
Noise Sensitive Receivers (NSRs) are controlled under the TMs and shall not
exceed the specified Acceptable Noise Levels (ANLs). These ANLs are stipulated
in accordance with the Area Sensitivity Ratings (ASRs) established for the
NSRs. The ANLs for construction works in Designated Areas are more stringent
than those given in the TM-GW and summarised in Table 4.2.
Table
4.2 ANLs for construction during
restricted hours
|
Time Period |
ANL, dB(A) |
||
|
ASR A |
ASR B |
ASR C |
|
|
All weekdays during the evening (1900 to 2300
hours), and general holidays (including Sundays) during the day-time and evening (0700 to 2300 hours) |
60 (45) |
65 (50) |
70 (55) |
|
All days during the night-time (2300 to 0700 hours) |
45 (30) |
50 (35) |
55 (40) |
Note:
[1] Figures in brackets are
ANLs for SPME construction work in designated areas.
4.1.2.7
As
defined in Noise Control Designated Area Plan, the assessment area of the
Project is not within the Designated Area.
4.1.2.8
Despite
any description made in this EIA, there is no guarantee that a 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 TMs issued under the NCO. The Noise
Control Authority will take into account contemporary
conditions / situations of adjoining land uses and any previous complaints
against construction activities at the Project site before making a decision in
granting a CNP. Nothing in this EIA report shall bind the Noise Control
Authority in making a decision. If a CNP is to be
issued, the Noise Control Authority shall include in it any conditions demand.
Failure to comply with any such conditions will lead to cancellation of the CNP
and prosecution under the NCO. According to the proposed construction
methodology for the Project, construction during
night-time period and other time periods under restricted hours are not
anticipated.
Percussive Piling
4.1.2.9
Under the TM-PP, CNPs are
required for carrying out of percussive piling during 0700 - 1900 hours of the
next day on normal weekdays, and carrying out of
percussive piling is generally prohibited during general holidays including
Sundays. This TM specifies the permitted hours and other conditions for
percussive piling. Table 4.3 lists
the acceptable percussive piling noise levels for various types of NSR.
Table
4.3 ANLs for percussive piling
|
NSR Window Type or Means
of Ventilation |
ANL, dB(A) |
|
(i) NSR (or part
of NSR) with no window 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 |
4.1.2.10
Depending on the numbers and
types of piling machines and pile types, and the separation from NSRs,
percussive piling would be restricted to 12, 5 or 3 hours respectively during
07:00 - 1900 hours on normal weekdays. For NSRs that
are particularly sensitive to noise, such as hospitals, medical clinics,
educational institutions and courts of law, a further reduction of 10dB(A)
shall be applied to the above ANLs. According to the proposed construction
methodology for the Project, percussive piling is not anticipated.
4.1.3
Operational
Noise
4.1.3.1
The
TM-EIAO (Annex 5 of TM) has stipulated the noise standards for various noise
sources as shown in Table 4.4. It
should, however, be noted that the following noise criteria are only applicable
to uses that rely on opened windows for ventilation.
Table 4.4 Noise standards
for operational phase
|
Common Uses |
Noise Standards[1],
[2] |
||||
|
Aircraft Noise
(Noise Exposure Forecast: NEF) |
Helicopter
Noise Lmax dB(A) 0700-1900
hours |
Road Traffic
Noise L10
(1hour) dB(A) |
Rail Noise |
Fixed Noise Sources |
|
|
All domestic premises including
temporary housing accommodation |
25 |
85 |
70 |
(a) The appropriate ANLs
shown in Table 2 of the Technical Memorandum for the Assessment of Noise from
Places Other than Domestic Premises, Public Places or Construction Sites and (b) Lmax
(2300-0700 hours) = 85dB(A) |
(a) 5dB(A) below the
appropriate ANLs shown in Table 2 of the Technical Memorandum for the
Assessment of Noise from Places Other than Domestic Premises, Public Places
or Construction Sites, or (b) the prevailing
background noise levels (For quiet areas with level 5 dB(A) below the ANL) |
|
Hotel and hostels |
25 |
85 |
70 |
||
|
Offices |
30 |
90 |
70 |
||
|
Educational institutions
including kindergartens, nurseries and all others where unaided voice
communication is required |
25 |
85 |
65 |
||
|
Places of public Worship and
courts of law |
25 |
85 |
65 |
||
|
Hospitals, clinics,
convalescences and homes for the aged, diagnostic rooms, wards |
25 |
85 |
55 |
||
Notes:
[1] The above standards apply to uses that 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 facade.
4.1.3.2
As
mentioned in Section 2, the main
objectives of the Project are to enhance pier facilities and provide adequate
structural integrity for safe pier usage. There is
neither planned increase in the existing Kaito
services nor alteration of their routing. Therefore, the Project will not
introduce any additional operational noise sources in Table 4.4.
4.2
Description of the Environment
4.2.1
Existing
Environment
4.2.1.1
As
discussed in Section 2, the works
area of the Project is located at the shore of Lai Chi Wo, mostly within Yan
Chau Tong Marine Park, and partly within Plover Cove Country Park. Part of the works area is currently occupied by
Lai Chi Wo Pier of approximately 64m long and 2.5m wide which would be subject
to pier improvement works under the Project. The adjacent area of the Project is
generally rural in character with Lai Chi Wo village located to about 400m
southwest of the Project. The Project and its adjacent area are currently
not covered by any Outline Zoning Plan (OZP). The
existing environment is relatively tranquil and quiet. No major noise sources
are identified during the site visit.
4.3
Assessment
Area and Noise Sensitive Receivers
4.3.1
Assessment
Area
4.3.1.1
According
to Clause 2.2.1(a) of Appendix C of the EIA Study Brief (ESB-305/2017), the
assessment area for noise impact should generally include the area within 300m
from the boundary of the Project and the works of the Project. A 300m assessment area from the works area of the Project has been adopted. Figure 4.1 shows the extent of the assessment area and the location of the
Project.
4.3.2
Noise
Sensitive Receivers
4.3.2.2
All
NSRs within the 300m assessment area from the boundary of the Project and the
works of the Project have been identified with the representative NSRs selected
as assessment points for assessment. These NSRs should include both the
existing and committed and planned sensitive developments (if any) during both
construction and operational phases.
4.3.2.3
The
representative existing NSRs are identified by means of reviewing topographic
maps, aerial photos, land status plans, relevant Outline Zoning Plans (OZP) (the
Approved Lai Chi Wo, Siu Tan and Sam A Tsuen OZP No. S/NE-LCW/2), Development Permission Area Plans, Outline
Development Plans, Layout Plans and other relevant published land use plans,
including plans and drawings published by Lands Department and any land use and
development applications approved by the Town Planning Board, and supplemented
by site inspections. No committed/planned NSR was identified within the 300m
assessment area from the boundary of the Project and the works of the Project. Photos
of the representative existing NSRs are shown in Appendix 4.1.
4.3.2.4
The
representative NSRs identified are summarised in Table 4.5 and their locations are shown in Figure 4.1.
Table 4.5 Identified
representative NSRs
|
NSR[1] |
Description |
Uses [2] |
Approx. Separation Distance |
|
LCW-N1 |
Plover Cove Country Park[3] |
CP |
Partly within the proposed works area |
Notes:
[1] The
nearest village house at Lai Chi Wo Village is located at more than 400m away
from the Project.
[2] CP – Country Park
[3] Floor is not applicable for this NSR.
4.4
Construction
Noise Impact Assessment
4.4.1
Identification
of Construction Noise Impact
4.4.1.1 As discussed in Section 1, the major works items for the Project include the following:
·
Carrying
out site investigation works for detailed design;
·
Provision of plants, equipment
and materials on working barge(s) for implementation of the Project;
·
Provision of temporary berthing
and mooring facilities (temporary pier) using working barge and/or steel
structures supported by piles to maintain access to Lai Chi Wo throughout the
construction stage;
·
Installation
of piles for the new pier;
·
Modification of the existing
pier and construction of new pier structures (e.g. installation of precast elements of the new pier structure
etc.);
·
Construction of associated
facilities on the new pier; and
·
Removal of temporary pier after
completion of the improvement works on the existing pier.
4.4.1.2
The
noise sources during the construction phase would be the use of Power
Mechanical Equipment (PME) in different construction works. The key
construction activities which have a bearing on construction noise impacts
include:
·
Site
investigation works for detailed design;
·
Mobilization,
pre-drilling works and construction of the temporary pier;
·
Installation
of piles for the new pier;
·
Construction
of the new pier structures;
·
Construction
of associated facilities on the pier; and
·
Demolition
of the temporary pier and reinstatement work.
4.4.1.3
The PME inventories would generally include tug boat, derrick
barge, rotary type drill rig, concrete saw/groover,
generator and barge-mounted mobile crane, etc. Detailed plant inventory and anticipated
utilisation rate provided and confirmed by the project engineer to be
applicable can be referred to Appendix 4.2.
4.4.2
Evaluation
of Construction Noise Impact
4.4.2.1
As discussed in Section 2, site investigation works for
detailed design of the Project are tentatively targeted to commence in mid-2021
for completion in end-2021. The
pier improvement works of the Project is tentatively targeted to commence in
Year 2023 for completion in Year 2025. There are neither residential premises
nor educational institutions within the 300m assessment area of the Project.
Only the Plover Cove Country Park, with limited transient hikers, is identified
as the NSR. Although the NSR is identified in accordance with Annex 13 of the TM-EIAO,
the relevant legislation and guidelines including TM-EIAO and TM-GW do not
provide a specific noise limit for Country Parks.
4.4.2.2
In view of the minor scale and low complexity of
the Project, it is anticipated that construction works during the restricted
hours (i.e. 19:00 to 07:00 on weekdays or any hours in general holidays
including Sunday) can be avoided through a better scheduling of works.
Moreover, as the site
investigation, foundation works and demolition works of the Project are marine-based,
only a limited air-borne construction noise would be generated. In addition, the construction
works of above-water superstructure will mainly be implemented using
prefabrication method as far as practicable. Prefabrication method could reduce
the amount of above-water noisy operations on-site, and the number of PME items
to be used would be limited. Therefore, no adverse construction noise impact is
anticipated.
4.4.3
Enhancement
Measures of Construction Noise Impact
4.4.3.1
Although
no adverse construction noise impact is anticipated, it is still recommended to
minimise the construction noise impact as far as practical. As such, the
following enhancement measures are recommended:
·
Good
site practices to limit noise emissions at the source;
·
Use
of quality powered mechanical equipment (QPME);
·
Use
of temporary noise barriers to screen noise from relatively
static PME; and
·
Alternative
use of plant items within one worksite, wherever practicable.
4.4.3.2
The
above enhancement measures would need to be implemented in worksites as good
practices where appropriate. “Recommended Pollution Control Clauses for Construction Contracts” promulgated
by EPD will be added to the Contract for future contractors to follow. Detailed descriptions of these enhancement
measures are given in the following sections.
Good Site
Management Practices
4.4.3.3
Good
site practice and noise management techniques could considerably reduce the
noise impact from construction site activities on nearby NSRs. The following
measures should be practised during each phase of construction.
·
only
well-maintained plant should be operated on-site and
plant should be serviced regularly during the construction programme;
·
machines
and plant (such as crane and generator) that may be in intermittent use should
be shut down between work periods or should be throttled down to a minimum;
·
silencers
or mufflers on construction equipment should be properly fitted and maintained
during the construction works;
·
mobile
plant should be sited as far away from NSRs as possible and practicable; and
·
material
stockpiles, site office and other structures should be effectively utilised,
where practicable, to screen noise from on-site construction activities.
4.4.3.4
The
benefits of these techniques can vary according to specific site conditions and
operations. The environmental noise climate would certainly be improved with
these control practices, although the improvement can only be quantified during
implementation when specific site parameters are known.
Use of Quality Powered Mechanical
Equipment (QPME)
4.4.3.5
The
use of quiet plant associated with the construction works is made
reference to the PME listed in the QPME system and other commonly used
PME listed in EPD web pages as far as possible. It is generally known
(supported by field measurement) that particular models
of construction equipment are quieter than standard types given in the TM-GW.
Whilst it is generally considered too restrictive to specify that the
Contractor has to use specific models or items of
plant, it is reasonable and practicable to set plant noise performance
specifications for specific PME so that some flexibility in selection of plant
is allowed. A pragmatic approach would be to request that the Contractor
independently verifies the noise level of the plant proposed to be used and
demonstrates through furnishing of these results, that the plant proposed to be
used on the Project site meets the requirements.
Use of Temporary Noise Barriers to Screen Noise from Relatively Static
PME
4.4.3.6
Movable
temporary noise barriers that can be located close to noisy plant and be moved
concurrently with the plant along a worksite can be very effective for
screening noise from NSRs. A typical design which has been used locally is a
wooden framed barrier with a small-cantilevered upper portion of superficial
density no less than 7kg/m2 on a skid footing with 25mm thick
internal sound absorptive lining. This measure is particularly effective for
low level zone of NSRs.
4.4.3.7
Movable
temporary noise barriers will be used for some PME items (e.g. generator). It
is anticipated that suitably designed barriers could achieve at least 5dB(A)
reduction for movable plant. Acoustic mat would be used for other plant items
such as piling rig and a 5 dB(A) noise reduction is anticipated.
Alternative Use of
Plant Items within One Worksite
4.4.3.8
In
practice, some plant items will operate sequentially within the same worksite,
and certain reduction of the predicted noise impacts could be achieved.
However, any additional control on the sequencing of plant will impose a
restrictive constraint to the Contractor on the operation and planning of plant
items, and the implementation of the requirement would be difficult to be
monitored.
4.4.3.9
The feasibility, practicability, programming and
effectiveness of the above enhancement measures have been reviewed by engineer.
4.4.4
Cumulative
Impact with Concurrent Project
4.4.4.1
As
discussed in Section 2, there is
only one concurrent project namely “Improvement of Trails and Provision of
Facilities in Sha Tau Kok” during the construction phase of the Project.
However, only minor replacement, renovation and
conservation works will be carried out for this project. Noise impact from this
project is expected to be minimal. In addition, the works of this concurrent project near the Project have all been
completed. Therefore, no adverse construction noise impact from the concurrent
project is anticipated.
4.4.5
Evaluation
of Residual Construction Noise Impact
4.4.5.1
With
the recommended construction design and enhancement measures in place, no
residual construction noise impact is anticipated.
4.5
Operational
Noise Impact Assessment
4.5.1.1 During the operational phase, the improved pier will not have any planned fixed noise sources. In addition, there would be no planned increase in the licensed Kaito services after the pier improvement works. Conversely, the main objectives of the Project are to enhance pier facilities and provide adequate structural integrity for safe pier usage. No loudspeakers, wind turbines or other fixed noise sources are proposed in the improved pier.
4.5.1.2
The
representative NSRs, as summarised in Table
4.5 are located to the west of the Project site. As
the pier length will increase from 64m to approximately 155m with the landing
steps shifted seawards, the proposed berthing locations associated with the
marine traffic noise sources will be farther away from the coast and the NSRs
as compared with the current condition without pier improvement. Therefore, no operational noise
impact is anticipated.
4.6.1
Construction
Phase
4.6.1.1
Only the Plover Cove Country Park is identified
as a NSR, partly encroaching the proposed works area.
However, the relevant legislation and guidelines including TM-EIAO, TM-GW, etc.
do not provide a specific noise limit for Country Parks.
4.6.1.2
Construction noise impact is anticipated to be
limited in view of the small scale and low complexity of the Project.
Furthermore, no construction works will be carried out during the restricted
hours, and the prefabrication method for the superstructure construction will
be adopted as far as practicable. In addition, a number of noise enhancement
measures including good site practices, the use of QPME,
and the use of temporary noise barriers, etc. have
been proposed in Section 4.4.3 to
further reduce the construction noise impact. Therefore, no adverse
construction noise impact is anticipated.
4.6.2
Operational
Phase
4.6.2.1
During
the operational phase, the improved pier will not have any planned fixed noise
sources. In addition, there would be no planned increase in the licensed Kaito services after the pier improvement
works. Therefore, no operational noise impact is anticipated.