This Section presents the potential construction and operational noise impacts associated with Designated Elements and Potentially Designated Elements of the proposed project.
4.2 Relevant
Legislation and Guidelines
4.2.1 Construction Noise
The principal legislation on the control of construction noise is the Noise Control Ordinance (Cap. 400) (NCO). Various Technical Memoranda (TMs), which stipulate control approaches and criteria, have been issued under the NCO. The following TMs are applicable to the control of noise from construction activities:
· Technical Memorandum on Noise from Percussive Piling (PP-TM);
· Technical Memorandum on Noise from Construction Work other than Percussive Piling (GW-TM); and
· Technical Memorandum on Noise from Construction Work in Designated Areas (DA-TM).
Apart from the above, the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) also provides means to assess construction noise impacts. The Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), issued under the EIAO, gives guidelines and criteria for evaluating construction noise impacts.
As the construction works considered in this Study are not carried out within a designated area ([1]) , the noise criteria as stipulated in the DA-TM would not be applicable
for this Study.
Percussive
Piling
Percussive piling is prohibited at any time on Sundays and public holidays and during the weekday evening and night-time hours (1900-0700 hours, Monday through Saturday). A Construction Noise Permit (CNP) is required for such works during the weekday daytime hours (0700-1900 hours, Monday through Saturday).
When assessing a CNP application for the carrying out of percussive piling, the Environmental Protection Department (EPD) is guided by the PP-TM. The EPD will look at the difference between the Acceptable Noise Levels (ANLs), as promulgated in the PP-TM, and the Corrected Noise Levels (CNLs) in conjunction with the proposed piling activities. Depending on the level of noise impact on nearby NSRs, the EPD would allow 3, 5 or 12 hours of daily piling time (see Table 4.2a).
Table 4.2a Permitted Hours of Operation for Percussive Piling (Not Involving the Use of Diesel, Pneumatic and/or Steam Hammers)
|
Amount
by which CNL exceeds ANL |
Permitted
hours of operation on any day not being a holiday |
|
more than 10 dB(A) |
0800 to 0900 and 1230 to
1330 and 1700 to 1800 |
|
between 0 dB(A) and 10
dB(A) |
0800 to 0930 and 1200 to
1400 and 1630 to 1800 |
|
no exceedance |
0700 to 1900 |
For any educational institutions, hospitals or medical clinics identified for this EIA Study, the ANLs should be adjusted by a -10 dB(A) correction factor in the subsequent noise assessment, taking account of the relative noise sensitivity of these uses.
As issuance of CNP by the Noise Control Authority regarding percussive piling would depend on the application submitted according to the procedures laid down in the PP-TM, a noise assessment with respect to percussive piling activities has been excluded in this study.
General Construction Works
Under the EIAO, noise impact arises from general construction works during normal working hours (i.e. 0700 to 1900 hours on any day not being a Sunday or public holiday) at the openable windows of buildings (which rely on opened windows for ventilation) is guided by the EIAO-TM. The EIAO-TM noise standards are presented in Table 4.2b.
Table 4.2b EIAO-TM Daytime Construction Noise Standard (Leq, 30 min dB(A))
|
Use |
Noise
Standard |
|
Domestic Premises |
75 |
|
Educational Institutions
(normal periods) Educational Institutions
(during examination periods) |
70 65 |
With reference to the EIAO-TM, there is no recommended construction noise standard currently provided for places of public worship. Therefore, a comparable type of land use criterion, those specified for educational institutions (non-exam period), has been applied as an indication of potential noise impacts. In this Study, the Leq, 30min 70 dB(A)
daytime construction noise criterion will be adopted for places of public worship.
The NCO provides statutory controls on general construction works during the restricted hours (i.e. 1900 to 0700 hours Monday to Saturday and at any time on Sundays and public holidays). The use of powered mechanical equipment (PME) for the carrying out of construction works during the restricted hours will require a CNP. The EPD is guided by the GW-TM when vetting such an application.
When vetting an application for the use of PME, the EPD will compare the ANLs based on the Area Sensitive Rating (ASR), as promulgated in GW-TM, with the CNLs (after accounting for factors such as barrier effect and reflection) associated with the proposed PME operations.
The ANLs are related to the noise sensitivity of the area in question and different Area Sensitivity Ratings have been drawn up to reflect the background characteristics of different areas. The relevant ANLs are shown in Table 4.2c.
According to the Annual Traffic Census 2000, neither the Annual Averaged Daily Traffic (AADT) flow on any identified major roads under consideration exceeds 30,000 vehicle per day (except Route 3 and San Tin Highway) nor information on slip roads in Au Tau area is available. Therefore, the ASR is assumed to be “A” or “B” to reflect a “worst case” scenario. Details of the ASR assumed for each NSR is presented in Table 4.3b.
Table 4.2c Acceptable Noise Levels (ANL, Leq, 5 min dB(A))
|
Time period |
Area Sensitivity Rating |
||
|
|
A |
B |
C |
|
All days during
the evening (1900-2300 hours) and general holidays (including Sundays) during
the day and evening (0700-2300 hours) |
60 |
65 |
70 |
|
All days during
the night-time (2300-0700 hours) |
45 |
50 |
55 |
The Noise Control Authority will consider a well-justified CNP application, once filed, for construction works within the restricted hours as guided by the relevant Technical Memorandum issued under the Noise Control Ordinance. The Noise Control Authority will take into account of 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 to include in it any condition he thinks fit. Failure to comply with any such conditions will lead to cancellation of the CNP and prosecution action under the NCO.
4.2.2 Fixed Noise Sources
Assessment of noise from fixed sources, including that from industrial-type establishments, is governed by the EIAO-TM and Technical Memorandum for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Site (IND-TM). The IND-TM establishes ANLs for fixed noise sources depending upon the sensitivity of the area where the NSR is located. The relevant ANLs are shown in Table 4.2d.
Table 4.2d Acceptable
Noise Levels (ANL, Leq, 30min dB(A))
|
Time
Period |
Area
Sensitivity Rating |
||
|
|
A |
B |
C |
|
Day and Evening (0700 to
2300 hours) |
60 |
65 |
70 |
|
Night (2300 to 0700 hours) |
50 |
55 |
60 |
The EIAO-TM requires that all fixed noise sources be located and/or designed such that:
· the total fixed source noise level at the facade of the nearest NSR is at least 5 dB(A) lower than the appropriate ANL 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 shall not exceed this background noise level.
Judging from the surrounding environment of the proposed development at Yuen Long and Kam Tin, the NSRs have been assumed with ASR of “A” or “B”. However, for the purpose of this Study, night-time background noise measurements have been conducted in the vicinity of the proposed sewage pumping stations (SPSs) sites as presented in Table 4.3a.
Since the proposed SPSs are anticipated to be operated on a 24-hour basis, the noise criteria are adopted by taking the measured night-time background noise levels or the ANL-5 dB(A) criterion stated in the EIAO-TM. The noise planning criteria for the NSRs are presented in Table 4.3b.
In either case, the ASR assumed here is for indicative assessment only given that, for example, details of the plant layout are not yet available. It should be noted that fixed noise sources are controlled under Section 13 of NCO. At the time of investigation, the Noise Control Authority shall determine noise impacts 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.
4.3 Baseline
environmental Conditions and Noise Sensitive Receivers
4.3.1 Baseline Environmental Conditions
The principal Designated and Potentially Designated Elements of the Project include the construction of a trunk sewerage system with five sections of sewers/rising mains and seven pumping stations. These elements are described in Section 2 and presented in Figure 2.1a.
The Project will be located in the sub-urban area of Kam Tin and Yuen Long. According to the proposed sewer alignments and locations of SPSs, most of the proposed sewers/rising mains will be laid along existing paved roads with the proposed pumping stations located nearby.
The area is generally rural in nature and with scattered residential developments and open storage sites. The existing residential developments are predominantly low-rises, consisting of villages such as Ko Po Tsuen, Ha Ko Po Tsuen, Nam Sang Wai, Fung Kat Heung, Mo Fan Heung, Shui Tsan Tin Tsuen, Kam Tin San Tsuen, Leung Uk Tsuen, Ng Ka Tsuen, Kam Tsin Wai, Kam Hing Wai and Tai Hong Wai, and other private residential premises such as Yuk Yat Garden Phases II & III and Kam Kong Villa.
The background noise environment at the area is generally tranquil except for areas located along major roads, in particular the Yuen Long Highway, Route 3, San Tin Highway, Castle Peak Road, Kam Tin Road, Kam Sheung Road and Fan Kam Road. Background noise levels in terms of Leq have been measured near the proposed SPSs and the results are presented in Table 4.3a.
Table 4.3a Background Noise Levels During Night-time (Leq, 30 min dB(A))
|
Location of the
Proposed Sewage Pumping Station (Ref ID) |
Background
Noise Level, Leq, 30 min |
Dominant Source
of Background Noise |
|
Kam Tin SPS (P1) |
54 |
Road Traffic on Kam Tin Road |
|
Sha Po SPS (P2) |
62 |
Road Traffic on Castle Peak Road and San Tam Road |
|
Nam Sang Wai SPS (P3) |
41 |
Noise from natural sources |
|
Shui Tsan Tin SPS (P4) |
64 |
Road Traffic on Kam Sheung Road |
|
Ng Ka Tsuen SPS (P5) |
55 |
Road Traffic on Kam Sheung Road |
|
Pang Ka Tsuen SPS (P6) |
43 |
Noise from natural sources |
|
Leung Uk Tsuen SPS (P7) |
67 |
Road Traffic on Kam Tin Road |
4.3.2 Identification of Noise Sensitive Receivers
Representative noise sensitive receivers (NSRs), as defined by EIAO-TM and section 3.5.2 (iii) of the Study Brief, have been identified. The locations of the representative NSRs are shown in Figures 4.3a to 4.3f and are listed in Table 4.3b.
Table 4.3b Identified Noise Sensitive Receivers
|
Work Item |
Proposed Pumping Station SPSs, Sewer/Rising Mains |
NSR ID |
Location |
Sensitive Uses |
No of Storey |
Influencing
Factor (IF) |
Degree to which
NSR is affected by IF |
ASR |
Daytime
Construction Noise Criteria |
Operational
Noise Criterion (Night-time) |
||
|
Potentially
Designated Elements |
|
|
|
|
|
|
||||||
|
S4 |
Sewers/Rising Mains Between
Kam Tin Sewage Pumping Station and Nam Sang Wai Sewage Pumping Station
(NSWSPS) |
D1 |
Scattered House near Kam
Tin Shi |
Residential |
2 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D3 |
Yuk Yat Garden Phase III |
Residential |
3 |
Route 3 |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D4 |
Yuk Yat Garden Phase II |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D5 |
Ko Po Tsuen |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D6 |
San Tao Home for the Aged |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D8 |
Ha Ko Po Tsuen |
Residential |
2 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D9 |
Planned CDA Site
(A/YL-KTN/60) |
Residential |
- (a) |
Route 3 & San Tin
Highway |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D11 |
Scattered House in Nam Sang
Wai |
Residential |
2 |
Route 3 & San Tin
Highway |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D12 |
Scattered House in Nam Sang
Wai |
Residential |
1 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D17 |
Scattered House near Route
3 |
Residential |
2 |
Route 3 |
Directly affected |
B |
75 |
50 (d) |
||
|
S6 |
Sewers/Rising Mains from
NSWSPS to Yuen Long Sewage Treatment Works (YLSTW) |
D13 |
Scattered House in Nam Sang
Wai |
Residential |
1 |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
|
|
D14 |
Planned Residential
Development (DPA/YL-NSW/12) |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
|
|
D15 |
Nam Sang Wai |
Residential |
1 |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
|
|
D42 |
Planned Tin Fook Wai
Residential Development |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
Potentially Designated
Elements |
|
|
|
|
|
|
|
|
||||
|
P1 |
Kam
Tin Sewage Pumping Station |
D1 |
Scattered
House near Kam Tin Shi |
Residential |
2 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D3 |
Yuk Yat Garden Phase III |
Residential |
3 |
Route 3 |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D4 |
Yuk Yat Garden Phase II |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d |
||
|
|
|
D17 |
Scattered House near Route
3 |
Residential |
2 |
Route 3 |
Directly affected |
B |
75 |
50 (d) |
||
|
P2 |
Sha Po Sewage Pumping
Station |
D18 |
Planned CDA Site
(A/YL-KTN/60) |
Residential |
- (a) |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D19 |
Fung Kat Heung |
Residential |
3 |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D21 |
Mo Fan Heung |
Residential |
3 |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
P3 |
Nam Sang Wai Sewage Pumping
Station |
D12 |
Scattered House in Nam Sang
Wai |
Residential |
1 |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
|
|
D13 |
Scattered House in Nam Sang
Wai |
Residential |
1 |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
|
|
D42 |
Planned Tin Fook Wai
Residential Development |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
41 (c) |
||
|
P4 |
Shui Tsan Tin Sewage
Pumping Station |
D40 |
Planned Residential
Development near Shui Tsan Tin (DPA/YL-KTS/82) |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D41 |
Shui Tsan Tin Tsuen |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
P5 |
Ng Ka Tsuen Sewage Pumping
Station |
D30 |
Scattered House beside Kam
Sheung Life Lutheran Church |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D31 |
Kam Sheung Life Lutheran
Church |
Place of Worship |
2 |
No IF in vicinity |
Not affected |
A |
- (e) |
45 (d) |
||
|
|
|
D32 |
Ng Ka Tsuen Historical
Building |
Residential |
2 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
P6 |
Pang Ka Tsuen Sewage
Pumping Station |
D24 |
Tai Hong Wai North |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D25 |
Kam Tin Tung Tak Public
School |
School |
1 |
No IF in vicinity |
Not affected |
A |
70/65 (b) |
- |
||
|
|
|
D26 |
Scattered House opposite to
proposed P6 |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D27 |
Hip Tin Kung |
Temple |
1 |
No IF in vicinity |
Not affected |
A |
70 |
43 (c) |
||
|
P7 |
Leung Uk Tsuen Sewage
Pumping Station |
D28 |
Scattered House opposite to
Leung Uk Tsuen |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D29 |
Leung Uk Tsuen |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
S1 |
Sewers/Rising Mains along
Kam Tin Main Drainage Channel from Shui Tsan Tin Sewage Pumping Station to Ng
Ka Tsuen Sewage Pumping Station |
D30 |
Scattered House beside Kam
Sheung Life Lutheran Church |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D31 |
Kam Sheung Life Lutheran
Church |
Place of Worship |
2 |
No IF in vicinity |
Not affected |
A |
- (e) |
45 (d) |
||
|
|
|
D32 |
Ng Ka Tsuen Historical
Building |
Residential |
2 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D33 |
Ng Ka Tsuen |
Residential |
2 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D36 |
Planned Residential
Development Beside Kam Tsin Wai (A/YL-KTS/174) |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D38 |
Kam Tsin Wai |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D39 |
Kam Kong Villa |
Residential |
2 |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D40 |
Planned Residential
Development near Shui Tsan Tin (DPA/YL-KTS/82) |
Residential |
- (a) |
No IF in vicinity |
Not affected |
A |
75 |
45 (d) |
||
|
S2 |
Sewers along Kam Tin Main Drainage
Channel from Pang Ka Tsuen Sewage Pumping Station to Kam Tin Sewage Pumping
Sewage Pumping Station |
D1 |
Scattered House near Kam
Tin Shi |
Residential |
2 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D3 |
Yuk Yat Garden Phases III |
Residential |
3 |
Route 3 |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D4 |
Yuk Yat Garden Phases II |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D5 |
Ko Po Tsuen |
Residential |
3 |
Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D6 |
San Tao Home for the Aged |
Residential |
3 |
Kam Tin Road & Route 3 |
Not affected |
A |
75 |
45 (d) |
||
|
|
|
D22 |
Kam Tin Shi North |
Residential |
2 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D23 |
Kam Hing Wai |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D24 |
Tai Hong Wai North |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D25 |
Kam Tin Tung Tak Public
School |
School |
1 |
No IF in vicinity |
Not affected |
A |
70/65 (b) |
- |
||
|
|
|
D26 |
Scattered House opposite to
proposed P6 |
Residential |
3 |
No IF in vicinity |
Not affected |
A |
75 |
43 (c) |
||
|
|
|
D27 |
Hip Tin Kung |
Temple |
1 |
No IF in vicinity |
Not affected |
A |
70 |
43 (c) |
||
|
S5 |
Branch Sewers/Rising Mains
from SPPS to S4 |
D18 |
Planned CDA Site
(A/YL-KTN/60) |
Residential |
- (a) |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D19 |
Fung Kat Heung |
Residential |
3 |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
|
|
D21 |
Mo Fan Heung |
Residential |
3 |
San Tin Highway |
Directly affected |
B |
75 |
50 (d) |
||
|
Notes: (a)
denotes planned NSR but with no available information on the number of storey
at this stage of assessment; (b)
denotes criteria for normal school period / examination period; (c)
criterion derived from measured background noise levels, dB(A); and (d) criterion derived from
the ANL - 5 dB(A) (e) sensitive uses do not rely on opened windows
for ventilation, therefore is excluded from the construction noise assessment |
||||||||||||
4.4 Identification
of Environmental Impacts
4.4.1 Construction Noise
During the construction phase of the Project, PME employed in the works will be the primary source of noise impacts affecting the surrounding environment. This assessment is based on the main construction activities during the period of August 2003 to November 2006.
In general, the construction activities can be divided into the following main categories which will include:
· general site clearance & demolition works;
· construction of sewage pumping stations;
· construction of sewers and rising mains using open trench method;
· construction of sewers and rising mains using pipe jacking method; and
· road pavement and finishes.
For
each of the construction activities, a list of PME teams (agreed by DSD) has
been adopted in this assessment and is presented in Table A2-1 of Annex A. Under each main category, the
construction works are divided into separate works item where a group of plant
team has been proposed for undertaking each works item. For example, the construction of sewage
pumping stations is divided into two works items including foundation works and
superstructure construction.
It has been assumed in this assessment that site clearance associated with the pumping station sites will be undertaken prior to the infrastructure works. Hence concurrent noisy construction works from these construction activities are not expected. The location of the proposed pumping station sites are shown in Figures 4.3a to 4.3f.
Most of the sewers and rising mains will be constructed by the open trench method. The sewers and rising mains are to be constructed underneath existing paved roads, where closure of the traffic lane will be necessary. The closed traffic lane will be the workfront for the sewers and rising mains construction (as indicated in Figures 4.3a to 4.3f) and road breaking will be required. It is expected that the sewers and rising mains will be constructed in segments of up to 50m in length at any one time and each workfront will be separated by a clearance distance of approximately 600m. Therefore, it is expected that the identified NSRs will only be affected by the construction activities associated with one workfront at any one time. The affected road surface will be reinstated once the sewers and rising mains have been laid. With the open trench method, it is expected that the use of a hydraulic vibratory sheet piling driver will be required to maintain the stability of the excavated area.
The pipe jacking method will be adopted where the sewers and rising mains will cross existing watercourses. It is expected that the construction noise will be restricted to the pit area only, as PME (such as the hydraulic jack) will mainly be underground. The noisiest construction activities associated with the pipe jacking method are expected to be from the formation of the pipe jacking pit using excavator mounted breakers and excavators.
To address the potential cumulative impacts which may arise from the large numbers of development projects proposed in the vicinity of the Study Area, a list of concurrent projects has been identified, based on the latest available information and are presented in Section 2. A preliminary construction programme together with other concurrent projects is shown in Table A1 in Annex A.
The construction activities have been divided into 4 stages to allow for the assessment of cumulative impacts. The construction activities in each stage considered in the impact assessment are summarised in Table 4.4a. Selected representative NSRs will be identified for assessing the potential cumulative impacts which may arise from these projects. Details of the assessment are presented in Section 4.6.1.
Table 4.4a Summary of Construction Activities for Cumulative Impact Assessment
|
Description |
Construction
Works |
|
Stage 1 - Year 2003 |
|
|
Package 1A-1T
(DE & PDE): |
· General Site
Clearance/Demolition Works · Construction of
Sewers and Rising Mains – S2, S4, S5 & S6 |
|
Package 1A-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 & S7 |
|
Other
Projects: |
· Construction of
Kam Tin Bypass · Construction of
Yuen Long Bypass Floodway |
|
|
|
|
Stage 2 – Year 2004 |
|
|
Package 1A-1T
(DE & PDE): |
· Construction of
Sewage Pumping Stations P1, P2 & P3 · Construction of
Sewers and Rising Mains S2, S4, S5 & S6 |
|
Package 1B-1T
(DE & PDE): |
· General Site
Clearance/Demolition Works · Construction of
Sewers and Rising Mains – S1 |
|
Package 1A-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 & S7 |
|
Package 1B-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 |
|
Package 1A-2T (NDE): |
· Construction of
Sewers and Rising Mains – S8 |
|
Other Projects: |
· Construction of
Yuen Long Bypass Floodway · Yuen Long, Kam
Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvement Stage 1 – Phase 2 |
|
Stage 3 – Year 2005 |
|
|
Package 1A-1T
(DE & PDE): |
· Construction of
Sewage Pumping Stations- P1, P2 & P3 · Construction of
Sewers and Rising Mains – S2, S4, S5 & S6 |
|
Package 1B-1T
(DE & PDE): |
· Construction of
Sewage Pumping Stations – P4, P5, P6 & P7 · Construction of
Sewers and Rising Mains – S1 |
|
Package 1A-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 & S7 |
|
Package 1B-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 |
|
Package 1A-2T (NDE): |
· Construction of
Sewers and Rising Mains – S8 |
|
Other Projects: |
· Construction of
Yuen Long Bypass Floodway · Yuen Long, Kam
Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvement Stage 1 – Phase 2 |
|
|
|
|
Stage 4 – Year 2006 |
|
|
Package 1A-1T: |
· Construction of
Sewers and Rising Mains – S2, S4, S5 & S6 |
|
Package 1B-1T |
· Construction of
Sewage Pumping Stations – P4, P5, P6 & P7 · Construction of
Sewers and Rising Mains – S1 |
|
Package 1A-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 & S7 |
|
Package 1B-1T (NDE): |
· Construction of
Sewers and Rising Mains - S3 |
|
Package 1A-2T (NDE): |
· Construction of
Sewers and Rising Mains – S8 |
|
Other Projects: |
· Yuen Long, Kam
Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvement Stage 1 – Phase 2 · YLKT SSDS stage
2 Ngau Tam Mei/San Tin Trunk Sewerage Phase 1 & 2 |
4.4.2 Operational Noise
During operation of the proposed sewage pumping stations, potential sources of noise include the extraction fans, deodourisation system and noise generated during operation of the air valves of the rising main. Since the proposed sewage pumping stations will operate for 24 hours each day, noise impacts on nearby NSRs are possible. The impacts from these noise sources will be addressed in Section 4.6.2.
4.5.1 Construction Noise
The assessment method will follow the procedures as outlined in the GW-TM, which has been issued under the NCO, and the EIAO-TM. In general, the methodology is as follows:
· locate representative NSRs that may be affected by the works;
· determine the plant teams for corresponding activities, based on agreed plant inventories;
· assign sound power levels (SWLs) to the PME proposed based on the GW-TM or other sources;
· calculate the correction factors based on the distance between the NSRs and the notional noise source position of the work sites;
· apply corrections such as potential screening effect and acoustic reflection, if any, in the calculations; and
· predict construction noise levels at NSRs in the absence of any mitigation measures.
The total sound power level associated with each activity has been established based on the assumed plant inventory (as agreed by DSD). The notional source position of each work site, according to the information provided by the Engineering Team of this Project, has been established in accordance with the procedure stated in the GW-TM. Noise impacts at NSRs were evaluated by comparing the predicted noise levels with the EIAO-TM daytime construction noise limits (Leq, 30min dB(A)), as presented in Section 4.2.1.
Other concurrent projects such as Kam Tin Bypass; Yuen Long Bypass Floodway; Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wan Drainage Improvement Works and the Non-designated elements of this Project have been considered. The assessment results of the Final EIA on the Kam Tin Bypass Design and Construction Consultancy, HyD, March 1996 (Agreement No. CE 7/94, PWP Item No. 6246TH) and the Final EIA on Yuen Long Bypass Floodway Feasibility Study, TDD, June 1998 (Agreement No. CE 79/96) have been taken into account.
4.5.2 Operational Noise
Potential noise sources at SPSs have been identified including extraction fans, deodourisation system and operation of air valves of the rising mains. As detailed information such as the number and location of extraction fans, location of air valves and building layout is currently unavailable, detailed noise calculations could not be undertaken. However, to ensure that the operations of the proposed SPS will comply with the EIAO-TM noise criteria, the maximum permissible SWLs will be calculated based on the measured distance of the closest NSRs. Taking a very conservative worst case scenario, the noise source is assumed to be at the site boundary and a 6 dB(A) tonal correction has been applied at each NSR.
4.6 Evaluation
of Environmental Impacts
4.6.1 Unmitigated Construction Noise
The unmitigated predicted noise levels at the worst case
representative NSRs for each construction activity are shown in Table A3-1 in Annex A taking into account the distance attenuation and facade
reflection.
Noise impacts arising from the project were examined as described below; however, a contractor may develop a different construction programme from the one presented in this report. The example given for each location serves to illustrate one possible combination to demonstrate the effect of construction activities operating concurrently. The examples provided are considered to represent a worst case scenario and are based on the preliminary construction programme presented in Annex A1.
Construction Noise Impact
Results presented in Table A3-1 in Annex A indicate that a maximum of 98 dB(A) is predicted from individual construction activity at NSRs D12, D31, D33 and D39, which is 23 dB(A) above the daytime criteria. The exceedance at these NSRs is because of their close proximity to the work site (less than 20m). In order to alleviate the daytime construction noise impacts, mitigation measures (see Section 4.7.1) are therefore required.
Based on the construction programme, the construction of the designated and potential designated elements would be constructed concurrently. To assess these impacts, the preliminary construction programme was used to identify the period when concurrent activities are expected. Details of the noise calculations are presented in Tables A4-1 to A4-4 in Annex A. The results are summarised in Table 4.7b.
Cumulative Noise Impacts
To present a “worst case” scenario, construction activities which may be carried out simultaneously are assumed to be concurrent throughout the construction period. In addition, the works items with the noisiest SWL will be adopted for predicting the cumulative construction noise levels. To address the extent of cumulative noise impacts, the preliminary construction programme (see Annex A1) was used to identify the period when cumulative impacts from other concurrent projects around the Study Area are expected. Construction works located within 500m of the NSRs identified for this Project have been included in the assessment.
As indicated in
Table 4.4a, the construction phase of
the proposed Yuen Long Kam Tin, Ngau Tam Mei and
Tin Shui Wai Drainage Improvement Stage 1 and proposed YLKT SSDS Stage 2 (Ngau Tam Mei/San Tin Trunk Sewerage Phase 1 & 2)
may coincide with the construction of this project.
As indicated in Figure 4.3d, NSRs located in Nam Sang
Wai (D12, D13 and D42) are the only NSRs that may impacted by the works
associated with YLKT SSDS Stage 2. However as the section of the sewer
located closest to these NSRs will only be constructed in late 2005 to 2008 (ie
after the completion of the sewer S6 and P3), cumulative impacts are not
expected.
In addition, as indicated in Figures 4.3a & 4.3b, NSRs D9 and D26
are the only receivers that may potentially be impacted by the works associated
with the Yuen Long Kam Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvement
Stage 1 during the construction of this Project (between the period of
early 2004 to mid 2006). It has
been identified that the closest construction works associated with the
drainage improvement works will be located at least 160m and 400m away from
NSRs D9 and D26, respectively.
Although information with regard to the construction process is
currently unavailable for use in this Project, it has been assumed as a worst
case scenario, that the noisiest construction activities associated with the
drainage improvement works are the site preparation and road opening works
(similar to those assumed for this Project), where the SWL of the construction
activities (with the use of quiet PME) would be 112 dB(A). Based on the above assumption, the
noise levels at NSRs D9 and D26 from the drainage improvement works would be 63
dB(A) and 55 dB(A) respectively.
Cumulative impacts are therefore not expected. Details of the assessments are shown in Tables A4-1 to A4-4 of Annex A.
NSRs located in Kam Tin, including NSRs D22, D23, D24, D25, D26, D27, and an NSR located in Nam Sang Wai (NSR D11) may be impacted by the works associated with the construction of the Kam Tin Bypass and Yuen Long Bypass Floodway, respectively. In addition, the identified NSRs located within the Kam Tin area (including NSRs D1, D3, D4, D5, D17, D22, D24, D25, D26, D27, D28, D29, D30, D31, D32, D33, D36, D38, D39, D40 and D41) will be affected by the works associated with the construction of non-designated elements of this Project. The potential cumulative impacts from these projects are assessed and are shown in Tables A4-1 to A4-4 of Annex A.
Based on the preliminary construction programme, the potential cumulative construction noise impacts during the period of August 2003 to November 2006 have been assessed and the results are summarised in Table 4.6a. Details of the noise calculations are presented in Tables A4-1 to A4-4 of Annex A. Exceedances of the daytime construction noise criterion are predicted at all identified NSRs except for the San Tao Home for the Aged (D6), Ha Ko Po Tsuen (D8), Planned CDA Site (D9), scattered house in Nam Sang Wai (D13) and the Planned Residential Development (DPA/YL-NSW/12) (D14) throughout the entire construction period from 2003 to 2006.
Although it is shown in Table 4.6a that noise exceedances will last over a four year period, it is anticipated that the actual noise exceedances would not last for such long periods as exceedances are likely only when the construction work is carried out adjacent to the NSRs (ie within a radius of about 50m). It is anticipated that the sewers and rising mains will be constructed in segments of up to a maximum of 50 m in length at any one time, and therefore the impacts are only expected on isolated occasions during the three month maximum construction period within the period from 2003 to 2006. Given the severity of the noise impacts, mitigation measures (see Section 4.7.1) are therefore required to alleviate the noise impacts.
Table 4.6a Predicted Cumulative Noise Levels (Included Other Projects), dB(A) (Unmitigated Scenario)
|
NSRs |
2003 |
2004 |
2005 |
2006 |
|
Scattered House near Kam Tin Shi (D1) |
90 |
90 |
90 |
90 |
|
Yuk Yat Garden Phases III (D3) |
86 |
86 |
86 |
85 |
|
Yuk Yat Garden Phase II (D4) |
95 |
95 |
95 |
95 |
|
Ko Po Tsuen (D5) |
80 |
80 |
80 |
79 |
|
San Tao Home for the Aged (D6) |
75 |
75 |
75 |
75 |
|
Ha Ko Po Tsuen (D8) |
74 |
74 |
74 |
74 |
|
Planned CDA Site (A/YL-KTN/60) (D9) |
74 |
74 |
74 |
74 |
|
Scattered House in Nam Sang Wai (D11) |
82 |
82 |
82 |
82 |
|
Scattered House in Nam Sang Wai (D12) |
98 |
98 |
98 |
98 |
|
Scattered House in Nam Sang Wai (D13) |
75 |
75 |
75 |
71 |
|
Planned Residential Development (DPA/YL-NSW/12) (D14) |
67 |
67 |
67 |
67 |
|
Nam Sang Wai (D15) |
83 |
83 |
83 |
83 |
|
Scattered House near Route 3 (D17) |
87 |
86 |
86 |
81 |
|
Planned CDA Site (A/YL-KTN/60) (D18) |
88 |
87 |
87 |
84 |
|
Fung Kat Heung (D19) |
91 |
90 |
90 |
84 |
|
Mo Fan Heung (D21) |
79 |
79 |
79 |
79 |
|
Kam Tin Shi North (D22) |
86 |
86 |
86 |
86 |
|
Kam Hing Wai (D23) |
85 |
84 |
84 |
84 |
|
Tai Hong Wai North (D24) |
82 |
81 |
81 |
81 |
|
Kam Tin Tung Tak Public School (D25) |
77 |
79 |
79 |
79 |
|
Scattered House opposite to proposed P6 (D26) |
85 |
93 |
93 |
93 |
|
Hip Tin Kung (D27) |
77 |
84 |
83 |
83 |
|
Scattered House opposite to Leung Uk Tsuen (D28) |
- |
91 |
91 |
91 |
|
Leung Uk Tsuen (D29) |
- |
87 |
87 |
87 |
|
Scattered House beside Kam Sheung Life Lutheran Church (D30) |
92 |
97 |
97 |
97 |
|
Ng Ka Tsuen (D33Historical Building (D32) |
78 |
90 |
89 |
89 |
|
Ng Ka Tsuen (D33) |
71 |
98 |
98 |
98 |
|
Residential Development beside Kam Tin Wai (A-YL-KTS-174) (D36) |
- |
90 |
90 |
90 |
|
Kam Tsin Wai (D38) |
- |
89 |
89 |
89 |
|
Kam Kong Villa (D39) |
- |
98 |
98 |
98 |
|
Planned Residential Development near Shui Tsan Tin (DPA/YL-KTS/-YL-KTS-82) (D40) |
- |
89 |
89 |
89 |
|
Shui Tsan Tin Tsuen (D41) |
- |
91 |
90 |
90 |
|
Planned Tin Fook Wai Residential Development (D42) |
85 |
85 |
85 |
85 |
|
Note: Exceedance of the daytime construction noise criterion of 70 dB(A)
for places of worship, 75 dB(A) for residential premises and 70-65 dB(A)
during normal-exam periods for school are shown in BOLD. |
||||
4.6.2 Operational Noise
A total of seven sewage pumping stations have been proposed under this project which will have potential noise impact on the nearby NSRs. Based on the methodology as described in Section 4.5.2, the maximum permissible SWLs at the site boundary will be calculated based on the noise criteria and measured distance of the closest NSRs. The recommended maximum permissible SWLs for each proposed SPS are presented in Table 4.6b.
Table 4.6b Recommended Maximum Sound Power Levels (SWL) for the Proposed Sewage Pumping Stations
|
Proposed SPS |
NSRs |
Distance (m) |
Criteria (dB(A)) (a) |
Max. Permissible SWL(b),
dB(A) |
|
Kam Tin SPS (P1) |
Scattered House near Route 3 (D17) |
25 |
50 |
77 |
|
Sha Po SPS (P2) |
Fung Kat Heung (D19) |
20 |
50 |
75 |
|
Nam Sang Wai SPS (P3) |
Scattered House in Nam Sang Wai (D13) |
140 |
41 |
83 |
|
Shui Tsan Tin SPS (P4) |
Shui Tsan Tin Tsuen (D41) |
100 |
45 |
84 |
|
Ng Ka Tsuen SPS (P5) |
Scattered House beside Kam Sheung Life Lutheran Church (D30) |
30 |
45 |
74 |
|
Pang Ka Tsuen SPS (P6) |
Scattered House at northwest to proposed pumping station, P6Hip Tin
Kung
(D27) |
65 |
43 |
78 |
|
Leung Uk Tsuen SPS (P7) |
Leung Uk Tsuen (D29) |
55 |
45 |
89 |
|
Notes: |
||||
|
a)
Refer to Table 4.3b for the
recommended planning noise criteria for each NSR. |
||||
|
Max Permissible SWL =
Criteria + 10 log (2pr2) -
6 dB Tonal Correction - 3 dB Facade Correction, where r
is the separation distance |
||||
|
|
||||
4.7 Mitigation
of Adverse Environmental Impacts
4.7.1 Construction Noise
Noise emissions from construction activities can be minimised through good site practice, selecting quiet plant, adopting quieter working methods, erection of noise barriers to screen the noise source, where appropriate, and posing restrictions on the use of noisy equipment. The mitigation measures detailed in this section should be incorporated into the Contract Specification in order to ensure the acceptable environmental performance of construction works.
Contractors may develop a different package of environmental control measures to meet the required noise standards, but the following illustrates a feasible approach to mitigate the predicted noise impact during the construction phase.
Good Site Practice
In view of the large number of construction activities and items of construction equipment considered in the Project, adverse construction noise impacts to the surrounding environment are possible, unless mitigation measures are applied. Good site practice and proper on-site measurement are required by Contractors at all times in order to minimise noise emissions from the works. The following measures are recommended.
· Only well-maintained plant shall be operated on-site and plant shall be serviced regularly during the construction works.
· Machines and plant that may be in intermittent use shall be shut down between work periods or should be throttled down to a minimum.
· Silencers or mufflers on construction equipment shall be utilised and be properly maintained during the construction works.
· Mobile plant shall be sited as far away from NSRs as possible.
· Material stockpiles and other structures shall be effectively utilised, where practicable, to screen noise from on-site construction activities.
Although it is difficult to quantify the level of noise reduction achieved from incorporation of these practices, the environmental performance of the works would be improved with these control measures.
Selecting Quieter Plant
The use of quiet plant is considered a feasible solution to tackle the adverse impacts associated with construction works. The Contractor may be able to obtain particular models of plant that are quieter than the standard types given in the GW-TM. The benefits achievable in this way will depend on the details of the Contractors’ chosen methods of working. It is considered too restrictive to specify that a Contractor has to use specific items of plant. It is therefore both preferable and practicable to specify an overall plant noise performance specification in term of total SWL on site, so that more flexibility is given to the Contractor for plant selection.
Quiet plant is defined as PME whose actual SWL is less than the value specified in the GW-TM for the same piece of equipment. Examples of SWLs for specific silenced PME taken from a British Standard, Noise and Vibration Control on Construction Open Sites, BS 5228: Part 1: 1997, which the silenced PME are known to be used (see Table 4.7a). With the use of quiet plant, the noise levels could be reduced by up to 11 dB(A) (see Table A3-2 in Annex A).
Table 4.7a Sound Power Levels for Specific Silenced PME
|
PME |
BS
5228 Table No. |
Ref.
No. |
SWL
dB(A) max |
|
Air Compressor |
C7 |
44 |
103 |
|
Backhoe |
C3 |
35 |
106 |
|
Bulldozer |
C9 |
2 |
104 |
|
Crawler Crane |
C7 |
110 |
106 |
|
Dump Truck |
C9 |
27 |
105 |
|
Excavator |
C3 |
97 |
105 |
|
Generator |
C7 |
62 |
100 |
|
Handheld Hydraulic Breaker |
C2 |
10 |
110 |
|
Excavator mounted breaker |
C3 |
18 |
110 |
|
Excavator for trenching |
C8 |
33 |
102 |
|
Wheeled Excavator-Loader |
C8 |
15 |
103 |
|
Concrete Lorry Mixer |
C6 |
35 |
100 |
|
Poker Vibrator |
C6 |
32 |
100 |
|
Lorry |
C9 |
27 |
105 |
|
Circular Saw |
C7 |
75 |
105 |
|
Roller |
C3 |
115 |
102 |
|
Asphalt Paver |
C8 |
24 |
101 |
|
Small/medium size trucks |
C9 |
19 |
102 |
It should be noted that various types of silenced equipment can be found in Hong Kong. However, when processing a CNP application, the EPD will apply the noise levels contained in the GW-TM unless the noise emission of a particular piece of equipment can be validated.
Restriction
in the Operating PME Time Usage and the Types of PME Used Concurrently
It is expected that during the construction of sewers
and rising mains, PME such as excavator mounted breakers and excavators would
not be operated concurrently as the works are usually carried out using the
same piece of equipment but with different attachments. Based on this assumption, the plant
groups have been further refined (as agreed by DSD) and the plant inventory is
shown in Table A2-3 in Annex A.
In
addition, by restricting the usage of some PME to 50% (ie the operation time of
some PME will be restricted to 15 minutes over each 30 minutes interval), the
noise levels generated from these PME can be further reduced by 3 dB(A). However, given that a reduced plant
inventory has been adopted and that the implementation mechanism for such
measures requires additional responsibilities to be placed on the Environmental
Team and the Independent Checker to ensure that the condition is met, this
mitigation measure is considered not to be practical for this Project.
Use of Temporary and Movable Noise Barriers
It is anticipated that the adoption of temporary noise barrier, in the form of a site hoarding (with a superficial density of at least 20kg/m2, with no substantial gaps), along the site boundary of the pumping station sites would also be practicable. Considering the low rise nature of the NSRs, the same level of noise reduction could also be achieved by erecting temporary noise barriers in the form of site hoardings along active work sites. Certain types of PME, such as generators, can be completely screened giving a total noise reduction of 10 dB(A) or more.
Although the works area for the sewer laying works will be very small (approximately 3 to 3.5m in width) and the excavated trench is expected to occupy most of the works area (most of the trunk sewer laying works will be using sewer sizes over 600mm in diameter), given the severity of the noise exceedances (up to 10 dB(A)) at the NSRs located close to the construction works, the benefit of using movable noise barriers and/or enclosures has been considered.
As
discussed above, the works area for the sewer laying works will be very
limited, and the use of mitigation measures such as movable noise barriers
and/or enclosures is only considered practicable for small sized PME. As road opening associated with the
sewer laying works is a very noisy activity, the use of handheld breakers
instead of excavator mounted breakers together with the use movable noise
barriers is recommended to further reduce the potential noise impacts at the
nearby NSRs. If there are NSRs
located on both side of the works area, the use of a movable noise enclosure
should also be adopted. A typical
example of a movable noise enclosure is shown in Figure A3 of Annex A2. Details of the predicted noise levels
with the implementation of the above mitigation measures are presented in Table A3-4 in Annex A.
However due to the physical constraints of the works area, it is considered that the use of movable noise barriers would not be feasible for other construction works such as trench excavation and sewer laying works, as these will require the use of large PME items (such as excavator, loader, lorry).
It is anticipated that the adoption of temporary
noise barriers, in the form of a site hoarding, along the site boundary of the
pumping station sites would also be practicable. Considering the low rise nature of the surrounding NSRs, the
temporary barrier would be an effective mitigation measure to further reduce
the noise impacts at NSRs located close to the pumping station sites. Details of the predicted noise levels
with the implementation of the above mitigation measures are presented in Table A3-4 in Annex A.
A summary of the potential construction noise impacts is presented in Table 4.7b.
As indicated in Table 4.7b, the use of handheld breakers and noise barriers is an effective mitigation measures package in reducing the noise impacts during the road opening works. However, exceedances of the daytime construction noise criteria were predicted at some NSRs where measures such as the use of movable noise barriers could not be employed. Exceedances were predicted due to the fact that the NSRs are located very close to the work sites and the physical constraints of the works area was such that movable noise barriers could not be deployed.
Table 4.7b Summary of Potential Construction Noise Impacts from the Construction Activities Associated with the Designated and Potentially Designated Elements (Unmitigated Levels are shown in brackets)
|
NSR
|
Location |
Noise
|
Source of Construction Noise |
Residual
Impact |
Approx.
No. |
||||
|
ID |
|
Criteria |
Site
Clearance |
SPS
Construction |
Sewer
(Open Trench) |
Sewer
(Pipe jacking) |
Road
Pavement |
|
of
Dwellings Affected |
|
D1 |
Scattered House
near Kam Tin Shi |
75 |
(72-73) 56-57 |
(70-71) 56-58 |
(88-90) 67-73 |
- |
(85) 80 |
· Residual impacts
of up to 5 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
6 |
|
D3 |
Yuk Yat Garden Phases III |
75 |
(77-78) 61-62 |
(75-77) 62-63 |
(80-85) 62-68 |
- |
(80) 75 |
Not expected |
- |
|
D4 |
Yuk Yat Garden Phase II |
75 |
(72-73) 56-57 |
(70-71) 56-58 |
(90-95) 71-78 |
- |
(89) 84 |
· Residual impacts
of up to 3 dB(A) during construction of sewers & rising mains. The duration is expected to be no
more than 3 months. · Residual impacts
of up to 9 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
45 |
|
D5 |
Ko Po Tsuen |
75 |
(72-73) 56-57 |
(70-71) 56-58 |
(71-79) 55-62 |
- |
(73) 68 |
Not expected |
- |
|
D6 |
San Tao Home for the Aged |
75 |
- |
- |
(70-75) 52-59 |
- |
(70) 65 |
Not expected |
- |
|
D8 |
Ha Ko Po Tsuen |
75 |
- |
- |
(69-74) 51-57 |
- |
(69) 63 |
Not expected |
- |
|
D9 |
Planned CDA Site (A-YL-KTN-60) |
75 |
- |
- |
(69-74) 51-58 |
- |
(69) 64 |
Not expected |
- |
|
D11 |
Scattered House in Nam Sang Wai |
75 |
- |
- |
(77-82) 59-65 |
(68-69) 52-56 |
(77) 71 |
Not expected |
- |
|
D12 |
Scattered House in Nam Sang Wai |
75 |
(67) 50-52 |
(64-66) 51-53 |
(93-98) 75-81 |
(65-67) 50-54 |
(93) 88 |
· Residual impacts
of up to 6 dB(A) during construction of sewers & rising mains. The duration is expected to be no
more than 3 months. · Residual impacts
of up to 13 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
6 |
|
D13 |
Scattered House in Nam Sang Wai |
75 |
(73) 56-58 |
(70-72) 57-59 |
(66-71) 48-54 |
(73-74) 57-61 |
(66) 61 |
Not expected |
- |
|
D14 |
Planned Residential Development
(DPA-YL-NSW-12) |
75 |
- |
- |
(62-67) 44-50 |
(63-65) 48-52 |
(62) 57 |
Not expected |
- |
|
D15 |
Nam Sang Wai |
75 |
- |
- |
(78-83) 60-67 |
(63-65) 48-52 |
(78) 73 |
Not expected |
- |
|
D17 |
Scattered House near Route 3 |
75 |
(85-86) 69-70 |
(83-85) 69-71 |
(75-80) 56-63 |
- |
(72) 67 |
Not expected |
- |
|
D18 |
Planned CDA Site (A-YL-KTN-60) |
75 |
(84-85) 68-69 |
(82-83) 68-70 |
(79-84) 61-67 |
- |
(79) 74 |
Not expected |
- |
|
D19 |
Fung Kat Heung |
75 |
(89-90) 73-74 |
(87-89) 74-75 |
(79-84) 61-67 |
- |
(79) 74 |
Not expected |
- |
|
D21 |
Mo Fan Heung |
75 |
(71-72) 55-56 |
(68-70) 55-57 |
(74-79) 55-62 |
- |
(73) 68 |
Not expected |
- |
|
D22 |
Kam Tin Shi North |
75 |
(65-66) 49-50 |
(63-65) 49-51 |
(81-86) 63-69 |
- |
(81) 76 |
· Residual impacts
of up to 1 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
5 |
|
D23 |
Kam Hing Wai |
75 |
- |
- |
(79-84) 61-67 |
- |
(79) 74 |
Not expected |
- |
|
D24 |
Tai Hong Wai North |
75 |
(67-68) 51-52 |
(64-66) 51-53 |
(76-81) 58-64 |
- |
(75) 70 |
Not expected |
- |
|
D25 |
Kam Tin Tung Tak Public School |
70/65 |
(73) 56-58 |
(70-72) 57-59 |
(71-76) 53-59 |
- |
(71) 66 |
Not expected |
- |
|
D26 |
Scattered House opposite to proposed P6 |
75 |
(79-80) 63-64 |
(77-79) 63-65 |
(80-85) 62-68 |
- |
(80) 75 |
Not expected |
- |
|
D27 |
Hip Tin Kung |
70 |
(80-81) 64-66 |
(78-80) 65-66 |
(72-77) 54-61 |
- |
(72) 67 |
Not expected |
- |
|
D28 |
Scattered House opposite to Leung Uk Tsuen |
75 |
(80) 64-65 |
(77-79) 64-66 |
- |
- |
- |
Not expected |
- |
|
D29 |
Leung Uk Tsuen |
75 |
(80-81) 64-66 |
(78-80) 65-66 |
- |
- |
- |
Not expected |
- |
|
D30 |
Scattered House beside Kam Sheung Life Lutheran Church |
75 |
(85-86) 69-70 |
(83-85) 69-71 |
(90-95) 71-78 |
- |
(89) 84 |
· Residual impacts
of up to 3 dB(A) during construction of sewers & rising mains. The duration is expected to be no
more than 3 months. · Residual impacts
of up to 9 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
9 |
|
D32 |
Ng Ka Tsuen Historical Building |
75 |
(89-90) 73-74 |
(87-89) 74-75 |
(66-71) 48-55 |
- |
(66) 60 |
Not expected |
- |
|
D33 |
Ng Ka Tsuen |
75 |
(71-72) 55-56 |
(69-71) 55-57 |
(93-98) 75-81 |
- |
(93) 87 |
· Residual impacts
of up to 6 dB(A) during construction of sewers & rising mains. The duration is expected to be no
more than 3 months. · Residual impacts
of up to 12 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
12 |
|
D36 |
Residential Development beside Kam Tin Wai (A-YL-KTS-174) |
75 |
- |
- |
(85-90) 67-73 |
- |
(85) 79 |
· Residual impacts
of up to 4 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
3 |
|
D38 |
Kam Tsin Wai |
75 |
- |
- |
(84-89) 65-72 |
- |
(83) 78 |
· Residual impacts
of up to 3 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
33 |
|
D39 |
Kam Kong Villa |
75 |
- |
- |
(93-98) 75-81 |
- |
(93) 87 |
· Residual impacts
of up to 6 dB(A) during construction of sewers & rising mains. The duration is expected to be no
more than 3 months. · Residual impacts
of up to 12 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
10 |
|
D40 |
Planned Residential Development near Shui Tsan Tin (DPA /YL-KTS/-YL-KTS-82) |
75 |
(71-72) 55-56 |
(68-70) 55-57 |
(84-89) 65-72 |
- |
(83) 78 |
· Residual impacts
of up to 3 dB(A) during road resurfacing. The duration is expected to be no more than 2 days. |
- (a) |
|
D41 |
Shui Tsan Tin Tsuen |
75 |
(76-77) 60-62 |
(74-76) 61-62 |
(70-75) 51-58 |
- |
(69) 64 |
Not expected |
- |
|
D42 |
Planned Tin Fook Wai Residential Development |
75 |
(71-72) 55-56 |
(69-71) 55-57 |
(80-85) 62-68 |
(83-85) 68-72 |
(80) 75 |
Not expected |
- (a) |
|
Note: Unmitigated noise levels are shown in
brackets Exceedance of the daytime construction noise
criteria are shown in BOLD (a)
For planned development, the number of potential NSRs being affected
by the construction noise is not known at this stage |
|||||||||
Cumulative Noise Impacts
The noise levels with the use of quiet plant, restriction of number of plant and the use of movable noise barriers have been calculated. A summary of the cumulative noise levels from the concurrent construction activities in the vicinity of Yuen Long and Kam Tin is presented in Table 4.7c. The predicted noise levels assuming no concurrent projects operating in the vicinity of the Study Area (shown in brackets) are also presented in Table 4.7c for reference. Details of the cumulative noise levels are presented in Table A4-5 to A4-8 in Annex A. Although it is shown in Table 4.7c that noise exceedances will last over a four year period, it is anticipated that the actual noise exceedances would not last for such long periods, as exceedances are likely only when the construction work is carried out adjacent to the NSRs (ie within a radius of about 50m). It is anticipated that the sewers and rising mains will be constructed in segments of up to a maximum of 50 m in length at any one time, and therefore the impacts are only expected on isolated occasions during the three month maximum construction period for each segment.
Table 4.7c Predicted Cumulative Noise Levels dB(A) - With the Use of Quiet Plant, Restriction of Plant (Numbers) and the Use of Movable Noise Barriers
|
NSRs |
2003 |
2004 |
2005 |
2006 |
|
Scattered House near Kam
Tin Shi (D1) |
(80) 80 |
(80) 80 |
(80) 80 |
(80) 80 |
|
Yuk Yat Garden Phases III (D3) |
(75) 75 |
(75) 75 |
(75) 75 |
(75) 75 |
|
Yuk Yat Garden Phase II (D4) |
(84) 84 |
(84) 84 |
(84) 84 |
(84) 84 |
|
Ko Po Tsuen (D5) |
(68) 68 |
(68) 68 |
(68) 68 |
(68) 68 |
|
San Tao Home for the Aged (D6) |
(65) 65 |
(65) 65 |
(65) 65 |
(65) 65 |
|
Ha Ko Po Tsuen (D8) |
(63) 63 |
(63) 63 |
(63) 63 |
(63) 63 |
|
Planned CDA Site (A-YL-KTN-60) (D9) |
(64) 64 |
(64) 66 |
(64) 66 |
(64) 66 |
|
Scattered House in Nam Sang Wai (D11) |
(71) 71 |
(71) 71 |
(71) 71 |
(71) 71 |
|
Scattered House in Nam Sang Wai (D12) |
(88) 88 |
(88) 88 |
(88) 88 |
(88) 88 |
|
Scattered House in Nam Sang Wai (D13) |
(62) 62 |
(63) 63 |
(63) 63 |
(61) 61 |
|
Planned Residential Development (DPA-YL-NSW-12)
(D14) |
(57) 57 |
(57) 57 |
(57) 57 |
(57) 57 |
|
Nam Sang Wai (D15) |
(73) 73 |
(73) 73 |
(73) 73 |
(73) 73 |
|
Scattered House near Route 3 (D17) |
(72) 72 |
(73) 73 |
(73) 73 |
(67) 67 |
|
Planned CDA Site (A-YL-KTN-60) (D18) |
(75) 75 |
(75) 75 |
(75) 75 |
(74) 74 |
|
Fung Kat Heung (D19) |
(77) 77 |
(78) 78 |
(78) 78 |
(74) 74 |
|
Mo Fan Heung (D21) |
(68) 68 |
(68) 68 |
(68) 68 |
(68) 68 |
|
Kam Tin Shi North (D22) |
(76) 77 |
(76) 76 |
(76) 76 |
(76) 76 |
|
Kam Hing Wai (D23) |
(74) 76 |
(74) 74 |
(74) 74 |
(74) 74 |
|
Tai Hong Wai North (D24) |
(70) 76 |
(70) 70 |
(70) 70 |
(70) 70 |
|
Kam Tin Tung Tak Public School (D25) |
(66) 71 |
(66) 68 (a) |
(66) 68 (a) |
(66) 68 (a) |
|
Scattered House opposite to proposed P6 (D26) |
(75) 76 |
(75) 82 |
(75) 82 |
(75) 82 |
|
Hip Tin Kung (D27) |
(67) 67 |
(69) 71 |
(70) 71 |
(70) 71 |
|
Scattered House opposite to Leung Uk Tsuen (D28) |
- |
(65) 79 |
(66) 79 |
(66) 79 |
|
Leung Uk Tsuen (D29) |
- |
(66) 76 |
(66) 76 |
(66) 76 |
|
Scattered House beside Kam Sheung Life Lutheran Church (D30) |
(81) 81 |
(84) 86 |
(84) 86 |
(84) 86 |
|
Ng Ka Tsuen Historical Building (D32) |
(67) 67 |
(75) 76 |
(75) 76 |
(75) 76 |
|
Ng Ka Tsuen (D33) |
(60) 60 |
(87) 88 |
(87) 88 |
(87) 88 |
|
Residential Development beside Kam Tin Wai (A-YL-KTS-174) (D36) |
- |
(79) 79 |
(79) 79 |
(79) 79 |
|
Kam Tsin Wai (D38) |
- |
(78) 78 |
(78) 78 |
(78) 78 |
|
Kam Kong Villa (D39) |
- |
(87) 87 |
(87) 87 |
(87) 87 |
|
Planned Residential Development near Shui Tsan Tin (DPA/YL-KTS/-YL-KTS-82) (D40) |
- |
(78) 78 |
(78) 78 |
(78) 78 |
|
Shui Tsan Tin Tsuen (D41) |
- |
(66) 79 |
(66) 79 |
(66) 79 |
|
Planned Tin Fook Wai Residential Development (D42) |
(75) 75 |
(75) 75 |
(75) 75 |
(75) 75 |
|
Note: ·
Noise levels assuming no concurrent projects are shown in brackets ·
The
impacts are only expected on isolated occasions for 2 – 3 days for
each segment
within the four year construction period |
||||
Similar to the constraints associated with designated and potential designated elements, the use of movable noise barriers for the sewer laying works may not be feasible for the non-designated elements. Exceedances of the daytime construction noise criteria from the non-designated elements of this Project are therefore predicted at NSRs D26, D28, D30 and D41. The causes of the exceedances are primarily from the construction of the sewers and rising mains where the construction activities are located very close (within 30m) to these sensitive uses. Residual impacts will be discussed in Section 4.8.
As indicated in Tables A4-5 to A4-8, cumulative impacts from projects such as the Yuen Long Bypass Floodway and Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wan Drainage Improvement Works are not predicted.
Potential cumulative impacts from the Kam Tin Bypass are expected at NSRs D22, D24, D25 and D26. Results indicated that although individual construction activities would not cause exceedances of the noise criteria, the cumulative effects of the two projects would cause marginal exceedances at these NSRs. To further reduce the noise impacts, re-scheduling of construction programmes to avoid undertaking concurrent construction works associated with the sewer laying works and Kam Tin Bypass are recommended.
Potential cumulative impacts from the non-designated elements of this Project are expected at NSRs D27, D29 and D32. Results indicated that although individual construction activities would not cause exceedances of the noise criteria, the cumulative effects of the works operating concurrently would cause marginal exceedances at these NSRs. To further reduce the noise impacts, re-scheduling of the construction programme to avoid the undertaking of construction works associated with the designated and non-designated elements of this Project concurrently is recommended.
A summary of the recommended mitigation measures for each of the construction activities is presented in Table 4.7d.
Table 4.7d Summary of
Proposed Mitigation Measures for Construction Noise Assessment
|
Activity ID |
Description |
Mitigation
Measures |
|
101 |
General Site Clearance - /Demolition Works |
· Use of quiet PME · Site hoarding along site boundary of the pumping station sites |
|
102-P1 102-P2 102-P3 102-P4 102-P5 102-P6 102-P7 |
Construction of Sewage Pumping Stations P1, P2, P3, P4, P5, P6 & P7 |
· Use of quiet PME · Site hoarding along
site boundary of the pumping station sites |
|
103 |
Sewers and Rising Mains using Open Trench Method |
· Use of quiet PME · Replacing excavator mounted breakers with handheld breakers during the initial road opening activities · Use of movable noise barrier or enclosures during the initial road opening activities where there are NSRs located within 50m of the works area |
|
104 |
Sewers and Rising Mains using Pipe Jacking Method |
· Use of quiet PME |
|
105 |
Road Pavement and Finishes |
· Use of quiet PME |
4.7.2 Operational Noise
With reference to the measurement carried out in the existing Ha Tsuen SPS (see Table A5-1 in Annex A), a SPL of 81 dB(A) was measured at 1m from the louvre opening. It has been confirmed by DSD, the existing Ha Tsuen SPS is currently without any acoustics treatment. In view of the above, the recommended maximum permissible SWLs are not particularly onerous and could be achieved by using conventional plant with the adoption of proper acoustic treatments and building design. Acoustic treatments such as silencers for ventilation fans could provide an insertion loss of about 25 dB or more; while acoustic louvres could offer a reduction of about 20 dB(A) or more. By incorporating the above recommendations, the recommended maximum permissible SWLs (see Table 4.6b) could be achieved, and therefore adverse noise impacts are not expected.
In addition, absorptive wall linings could also be used to further reduce the internal reverberant noise. Basic building design such as to avoid any opening or louvres facing the nearest NSR should also be adopted.
It is recommended that further noise assessment should be carried out during the detailed design stage of the proposed sewage pumping station to identify the type of mitigation measures required for meeting the recommended maximum permissible SWLs.
4.8 Residual
Environmental Impacts
4.8.1 Construction Noise
Practical noise abatement measures, such as the use of quieter plant, rescheduling of works to avoid the concurrent undertaking of noisy activities, the erection of temporary noise barriers along site boundaries and the use of movable noise barriers/enclosures, where possible, have been considered and recommended in this Project. As indicated in Section 4.7, even with the adoption of such mitigation measures, exceedances of the daytime construction noise criteria are still predicted at some of the NSRs located close to the construction works.
The causes of the noise exceen dances are primarily from the construction of the sewer & rising mains and the road reinstatement work. Mitigation measures such as movable noise barriers could not be used due to practical constraints. Other quieter/alternative construction methode such as the pipe jacking method have also been explored. However, for sewers running along roads such as the Kam Tin Road where a site may be full of utilities or hard obstructions and where a number of manholes are required for future drainage connection(1), pipe jacking method would not be a suitable or practical
construction method.
Nevertheless, due to the nature of the construction work, it is envisaged that the exceedances are likely only when the construction work is carried out adjacent to the NSRs (ie within a radius of about 50m). It is anticipated that the sewers and rising mains will be constructed in segments of up to a maximum of 50 m in length at any one time, and therefore the impacts are only expected to last for a relatively short period of time.
For each 50 m segment, the site preparation is anticipate to be completed in 2 weeks, while the construction period for the sewer laying work is estimated to be about 2 to 3 months. The duration of excessive construction noise impact will therefore be less than 3 months. However, the progress of works is subject to other variables, such as inclement weather, conflicts with existing utilities and restrictions on road closure during peak hours. Beyond a distance of 50m, the noise levels arising from the construction works will be reduced to within the daytime construction noise criteria.
Reinstating the affected roadworks would have the potential to cause noise exceedances. However, since the length of the road to be surfaced will be short (maximum of 50m), it is anticipated the resurfacing works would be completed in 1 to 2 days.
The extent and duration of the predicted residual impacts are presented in Table 4.7b. In addition, the approximate number of dwellings being affected by the residual impacts are also shown.
Cumulative Impacts
Even with re-scheduling the construction works, potential cumulative impacts from the non-designated elements of this Project are also expected at NSRs D26 (scattered house opposite to P6), D28 (scattered house opposite to Leung Uk Tsuen), D30 (scattered house beside Kam Sheung Church) and D41 (Shui Tsan Tin Tsuen) where the construction works are located very close (within 30m) to these sensitive uses. Similar to the constraints associated with designated and potentially designated elements as discussed above, the use of practicable mitigation measures is considered to have been exhausted and residual cumulative impacts from reinstating the affected roadworks are expected at these NSRs. Nevertheless, it is anticipated that reinstating the affected roadworks (maximum of 50m) would be completed in 1 to 2 days. Beyond 50m, the noise levels arising from the construction works will be reduced to within the daytime construction noise criteria.
4.8.2 Operational Noise
Residual noise impacts are not expected from the operation of the Project provided that the appropriate noise abatement measures as mentioned in Section 4.7.2 are incorporated in the Detailed Design.
4.9 Environmental
Monitoring and Auditing
4.9.1 Construction Noise
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 monitoring exercise. All the recommended mitigation measures should be incorporated into the EM&A programme for implementation during construction.
4.9.2 Operational Noise
In order to ensure that compliance with the noise limits specified in this report are achieved, operational noise monitoring at the site boundary of the proposed sewage pumping stations will be required during the commissioning stage.
4.10 Conclusions
4.10.1 Construction Noise
A construction noise assessment has been undertaken taking the cumulative impacts arising from other projects proposed in the vicinity of the Study Area of this Project into consideration. Unmitigated sources of construction noise associated with the proposed development would cause exceedances of the daytime construction noise criteria. Mitigation measures such as quiet plant, limiting the use of PME and movable noise barriers have been recommended.
As the works area for the sewer laying works will be small, the use of mitigation measures such as movable noise barriers and/or enclosures are only considered practicable for small size PME. As road opening is the noisiest construction activity associated with the sewer laying works, the use of handheld breakers instead of excavator mounted breakers, together with the use of movable noise barriers and/or enclosures is recommended to further reduce the potential noise impacts at the nearby NSRs. However, in view of the close proximity of some NSRs to the works site, exceedances are predicted, even allowing for all practical mitigation measures being implemented. It is anticipated that the sewers and rising mains, will be constructed in segments of up to 50 m in length and the noise exceedances may arise on isolated occasions during the three month maximum period required to construct each segment.
It is recommended that regular monitoring of noise at NSRs as part of the EM&A programme will be required during the construction phase.
4.10.2 Operational Noise
Noise impacts due to the proposed sewage pumping stations would not be insurmountable, provided that the planning recommendations described in Section 4.7.2 are followed.
4.11 Impact
Summary
The noise impacts during the construction and operational phase of the proposed development are summarised in Table 4.11a.
Table 4.11a Noise
Impacts Summary
|
Parameters |
Construction Phase |
Operational Phase |
|
Assessment Criteria |
Daytime (0700-1900 hours) construction noise standards stipulated in
the EIAO-TM is Leq 30 min 75 dB(A)
for all domestic premises, 70 for place of worship, 65 for hospital and 70
dB(A) for educational premises (65 dB(A) during examination) on any day not
being a Sunday or general holiday for general construction works. |
Fixed Plant Noise The EIAO-TM requires that
all fixed noise sources be located and /-or designed such that: · the total fixed
source noise levels at the facade of the nearest NSR is at least 5 dB(A)
lower than the appropriate ANL as specified in the IND-TM; or · where the
prevailing pre-Project 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
pre-Project noise level. |
|
Assessment Point |
· Scattered House
near Kam Tin Shi (D1) · Yuk Yat Garden
Phases III (D3) · Yuk Yat Garden
Phases II (D4) · Ko Po Tsuen (D5) · San Tao Home for
the Aged (D6) · Ha Ko Po Tsuen
(D8) · Planned CDA Site
(A-YL-KTN-60) (D9) · Scattered House
in Nam Sang Wai (D11) · Scattered House
in Nam Sang Wai (D12) · Scattered House in
Nam Sang Wai (D13) · Planned
Residential Development (DPA-YL-NSW-12) (D14) · Nam Sang Wai
(D15) · Scattered House
near Route 3 (D17) · Planned CDA Site
(A-YL-KTN-60) (D18) · Fung Kat Heung
(D19) · Mo Fan Heung
(D21) · Kam Tin Shi
North (D22) · Kam Hing Wai
(D23) · Tai Hong Wai
North (D24) · Kam Tin Tung Tak
Public School (D25) · Scattered Ouse
opposite to proposed SPS (D26) · Scattered House
at northwest to proposed P6Hip Tin Kung (D27) · Scattered House
opposite to Leung Uk Tsuen (D28) · Leung Uk Tsuen
(D29) · Scattered House
beside Kam Sheung Life Lutheran Church (D30) · Ng Ka Tsuen
historical building (D32) · Ng Ka Tsuen
(D33) · Planned
Residential Development beside Kam Tsin Wai (A-YL-KTS-174) (D36) · Kam Tsin Wai
(D38) · Kam Kong Villa
(D39) · Planned
Residential Development near Shui Tsan Tin (DPA/YL-KTS/-YL-KTS-82) (D40) · Shui Tsan Tin
Tsuen (D41) · Planned Tin Fook
Wai Residential Development (D42) |
· Scattered House
near Route 3 (D17) · Fung Kat Heung
(D19) · Scattered House
at Nam Sang Wai (D13) · Shui Tsan Tin
Tsuen (D41) · Scattered House beside
Kam Sheung Life Lutheran Church (D30) · Scattered House
opposite to the proposed pumping station P6 (D26) · Leung Uk Tsuen
(D29) |
|
Activities |
Main construction activities categorises
include: · general site
clearance & demolition works · construction of
sewage pumping stations · construction of
sewers and rising mains using open trench method · construction of
sewers and rising mains using pipe jacking method · road pavement
and finishes |
Main noise sources during the operational phase
of the following proposed sewage pumping stations: · Kam Tin SPS (P1) · Sha Po SPS (P2) · Nam Sang Wai SPS
(P3) · Shui Tsan Tin
SPS (P4) · Ng Ka Tsuen SPS
(P5) · Pang Ka Tsuen
SPS (P6) · Leung Uk Tsuen
SPS (P7) |
|
Mitigation Measures (if required) |
General Site
Clearance - /Demolition Works · Use of quiet PME ·
Site
hoarding along site boundary of the pumping station sites Construction of
Sewage Pumping Stations P1, P2, P3, P4, P5, P6 & P7 · Use of quiet PME · Site hoarding along
site boundary of the pumping station sites Sewers and Rising
Mains using Open Trench Method · Use of quiet PME · Replacing excavator mounted breakers with handheld breakers during the initial road opening activities · Use of movable noise barrier or enclosures during the initial road opening activities where there are NSRs located within 50m of the works area Sewers and Rising
Mains using Pipe Jacking Method · Use of quiet PME Road Pavement and
Finishes · Use of quiet PME |
Fixed Noise
Source Operational
noise impacts are not expected from the proposed project provided that the
appropriate acoustic treatment and building design are to be incorporated
into the Detailed Design Stage |
|
Residual Impacts |
Exceedances of the daytime construction
noise criteria are predicted at the following NSRs: · Scattered House
near Kam Tin Shi (D1) · Yuk Yat Garden
Phases II (D4) · Scattered House
in Nam Sang Wai (D12) · Kam Tin Shi
North (D22) · Scattered House
beside Kam Sheung Life Lutheran Church (D30) · Ng Ka Tsuen
(D33) · Planned
Residential Development beside Kam Tsin Wai (A-YL-KTS-174) (D36) · Kam Tsin Wai
(D38) · Kam Kong Villa
(D39) · Planned
Residential Development near Shui Tsan Tin (DPA/YL-KTS/-YL-KTS-82) (D40) |
No residual impacts are predicted. |
|
Implementation (when and by whom) |
All the mitigation measures should be implemented by the Contractor |
All
the mitigation measures should be implemented by the Contractor. |
|
EM&A Requirements (if required) |
EM&A is required during the construction of the proposed
development. |
Operational noise monitoring will also be required during the
commissioning stage of the proposed SPSs to ensure that compliance with the
noise limits specified in this report has been achieved. |
(1) Manhole to manhole distance is of approximately 80m interval for gravity sewer with diameter greater than 600mm and about 40m for smaller sewer size (for ease of maintenance).