5.1.1.3 Potential construction air-borne noise impacts will be generated from activities including excavation, cut and cover tunnelling, backfilling and construction of above ground structures in the form of the ventilation buildings at Cha Kwo Ling and the South Apron. In addition, ground-borne noise impacts could arise as a result of the adoption of the Tunnel Boring Machine (TBM) for the sub-sea tunnel construction. No blasting works would be required for the construction of the Trunk Road T2. Operationally, impacts could arise from the road traffic noise and fixed noise from the operation of the ventilation buildings.
5.2 Environmental Legislation, Standards and Guidelines
5.2.1 Background
· The TM on EIA process (EIAO-TM);
· The TM on Noise from Construction Work other than Percussive Piling (GW-TM);
· The TM on Noise from Construction Work in Designated Areas (DA- TM); and
· The TM for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Sites (IND-TM).
5.2.1.3 No percussive piling is proposed for the project and as such the Technical Memorandum on Noise from Percussive Piling will not be relevant to the noise assessment and is not discussed further. Notwithstanding, percussive piling is prohibited at any time on Sundays and public holidays and during the weekday evening and night-time hours (1900-0700hrs, Monday through Saturday) and a CNP would be required if such works were eventually needed.
5.2.2 Construction Phase
Noise
Standards for Non-restricted Hours
5.2.2.1 Daytime construction noise, excluding percussive piling, between the hours 0700 – 1900 on weekdays, that is non-restricted hours, is controlled under the EIAO-TM. Annex 5 of the EIAO-TM sets out the construction noise assessment limits, which are Leq(30 min) 75dB(A) for domestic premises and hotels, and Leq(30 min) 70dB(A) during normal hours for education institutions including kindergartens (65dB(A) during examination periods), nurseries and all other places where unaided voice communication is required.
Noise
Standards for Restricted Hours
5.2.2.2 Between 1900 and 0700 hours and all day on Sundays and public holidays, activities involving the use of powered mechanical equipment (PME) for the purpose of carrying out construction work is prohibited unless a Construction Noise Permit (CNP) has been obtained. A CNP may be granted in cases where the noise can be contained within the Acceptable Noise Level (ANL) at the NSRs. ANLs are assigned depending on the Area Sensitivity Ratings (ASRs). The corresponding basic noise levels (BNLs) for evening and night-time periods are given in Table 5.1.
Table 5.1 Construction Noise Criteria for Restricted Working Hours for Activities other than Percussive Piling
Time Period |
Basic
Noise Levels (BNLs), dB(A) |
||
|
Area
Sensitivity Rating A |
Area
Sensitivity Rating B |
Area
Sensitivity Rating C |
|
|
Evening (1900 to 2300 hrs)
[a] |
60 (45) |
65 (50) |
70
(55) |
|
Night (2300 to 0700 hrs) |
45 (30) |
50 (35) |
55
(40) |
[a] Includes Sunday and Public Holidays during daytime and evening.
Figures in brackets are BNLs for SPME construction work in designated areas.
5.2.2.4 There is no guarantee that a CNP will be granted for the proposed works. The noise control authority will consider a well-justified CNP application and be guided by the relevant TM and the NCO and will also take into account contemporary issues on adjoining land uses and previous noise complaints related to construction activities at the site before deciding whether to grant a CNP. As noise in restricted periods is covered by the NCO, it is not assessed further in this EIA under the EIAO.
· Erecting or dismantling of formwork or scaffolding;
· Loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material; and
· Hammering.
Construction
Ground-Borne Noise
5.2.2.8 Construction ground-borne noise is under the control of the EIAO for periods between 0700-1900 (except General Holiday & Sunday) and the subsidiary GW-TM for periods between 1900 – 2300 and 2300 – 0700 if no Specified Powered Mechanical Equipment (SPME) is used. Under the IND-TM, the criteria for noise transmitted primarily through the structural elements of the building or buildings should be 10dB(A) less than the relevant acceptable noise level (ANL). The criteria applied for the ground-borne noise assessment are, therefore, summarised in Table 5.2.
Table 5.2 Construction Ground-borne Noise Criteria
|
NSR Description |
Construction
Ground-Borne Noise Criteria, dB(A) |
||||||
|
Daytime (0700-1900 hrs) |
Daytime during general holidays and Sundays and all days during Evening |
Night-time |
|||||
|
A |
B |
C |
A |
B |
C |
||
|
Education
institutions |
60/55(i) |
50 |
55 |
60 |
(ii) |
||
|
Domestic premises, hotels, hospitals and
clinics |
65 |
50 |
55 |
60 |
35 |
40 |
45 |
|
Churches/temples, libraries and courts |
60 |
50 |
55 |
60 |
(ii) |
||
(i) A 5dB(A) reduction to the ground-borne noise criteria is recommended for school during examination period.
(ii) No sensitive use during this period.
5.2.2.9 In setting the noise criteria for the NSRs, it will be assumed that there are no influencing factors (IF) affecting the NSR. Since ground-borne noise affects internal areas, it is likely that there will be occupied spaces within the buildings which will not be affected by the IF, for example on the other side of the building or not on a building façade.
· Traffic noise from the open sections of Trunk Road T2 and the adjacent existing and planned trunk and local road networks within the 300m study area; and
· Noise emissions from the ventilation buildings of Trunk Road T2.
Operational
Traffic Noise
5.2.3.2 The EIAO-TM provides guidance on the acceptable road traffic noise levels at uses which rely on the open windows for ventilation. The relevant criteria are shown in Table 5.3.
Table 5.3 Road Traffic Noise Planning Criteria
|
Common Uses |
Road Traffic Noise, L10
(1hour), dB(A) |
|
Domestic Premises |
70 |
|
Hotel and Hostels |
70 |
|
Offices |
70 |
|
Educational Institutes |
65 |
|
Places of public worship and courts of
law |
65 |
|
Hospitals & Clinics |
55 |
Note: The above criteria apply to noise sensitive uses which rely on open window for ventilation and should be viewed as the maximum permissible noise levels assessed at 1m from the external facades.
Operational
Fixed Plant Noise
5.2.3.3 The NCO and IND-TM control noise from fixed noise sources such as ventilation shafts, chillers and cooling towers. For the assessment of impacts from these fixed noise sources, the ASR of the NSRs must be determined in accordance with the IND-TM, and then based on the ASR, the appropriate ANL can be determined. The ANL is shown in Table 5.4.
Table 5.4 Acceptable Noise Level for Fixed Plant Noise
Time Period |
NCO Criteria(1) |
EIAO-TM(1) |
||||
|
ASR ‘A’ |
ASR ‘B’ |
ASR ‘C’ |
ASR ‘A’ |
ASR ‘B’ |
ASR ‘C’ |
|
|
Daytime and Evening (0700-2300 hrs) |
60 |
65 |
70 |
55 |
60 |
65 |
|
Night-time (2300-0700 hrs) |
50 |
55 |
60 |
45 |
50 |
55 |
Source – IND-TM
Note (1): ASR in this context refers to Area Sensitivity Rating
5.2.3.4 The project spans from the former Kai Tak Airport South Apron, through the Kwun Tong Typhoon Shelter (KTTS), making landfall at the Cha Kwo Ling Public Cargo Works Area (PCWA). In respect of the Noise Sensitive Receivers (NSRs) located at the South Apron, reference has been made to the Schedule 3 EIA Report for Kai Tak Development (EIA-157/2008), but it is anticipated that due to the urban nature of the area and the presence of the Trunk Road T2 as an influencing factor, most NSRs would be subject to significant traffic influences and an ASR of C has, therefore, be allocated. However, in the Cha Kwo Ling area, which is a more rural residential in nature with lesser traffic influences, an ASR of B has been allocated. The details of the Area Sensitivity Ratings for the identified NSRs are provided in Table 5.5 and Table 5.6 below for the construction and operational phases, respectively.
5.2.3.5 The ASR is indicative only and the noise from the fixed sources is controlled under Section 13 of the NCO. The prevailing legislation, contemporary conditions and adjoining land use should be considered in determining noise impact.
· Criteria (1): 5dB(A) below the appropriate ANL set out in the IND-TM; and
· Criteria (2): The prevailing background noise level where this is 5dB(A) below the appropriate ANL (i.e. ANL -5dB(A)).
Operational
Ground-Borne Noise
5.2.3.8 No operational ground-borne noise impacts are predicted from the operation of the road project, and, therefore, an operational ground-borne noise assessment is not required.
5.3.1.1
The existing environment in the
study area is comprised of an urban industrial area at
5.4.1.1 Valid existing and planned future NSRs for the construction phase noise assessment have been identified at both the South Apron and in Cha Kwo Ling. The selected NSRs for the construction phase are shown in Figures 5.1a and 5.1b and detailed in Table 5.5 below. Further details of the NSRs are presented in the following sections.
5.4.1.2 There are no existing NSRs within the South Apron area. At Cha Kwo Ling, identified existing NSRs are residential village houses in the Cha Kwo Ling village, mid-rise residential developments in Cha Kwo Ling and the Tin Hau Temple, all of which are located within the vicinity of the Trunk Road T2 tunnel landing (Figure 5.1b).
5.4.1.3 The planned developments projects in the Kai Tak Development (KTD) and the Cha Kwo Ling area have been discussed in Section 3. As per the respective Outline Zoning Plan (OZP) No. S/K22/4 gazetted on 14 September 2012 for the South Apron and OZP S/K15/19 gazetted on 17 June 2011 for the Cha Kwo Ling, Yau Tong and Lei Yue Mun, provided in Figures 9.5.1 to 9.5.6, there will be four hospitals planned to be implemented at the South Apron within 300m of the Trunk Road T2 project boundary, namely the Centre of Excellence in Paediatrics (CEP), the Centre of Excellence in Neuroscience (CEN), the New Acute Hospital (NAH), the future KTD private hospital and two residential developments at Cha Kwo Ling within 300m of the Trunk Road T2 project boundary at ex-Cha Kwo Ling Kaolin Mine Site (ex-CKLKMS) and Yau Tong Bay (YTB).
5.4.1.4
The construction schedules for
the CEN, NAH and KTD private hospital, to be established at Site B of 3C1 at
the South Apron, are not available at the time of preparation of this EIA
Report (see summary list of concurrent projects in Appendix 3C), but the CEP is anticipated to be constructed between September
2013 and June 2017 and in operation in mid 2018. Thus, only the CEP is identified as a future
NSR during both construction and operation phases, while the other hospitals
are identified as future NSRs during operation phase only. The establishment of the Centres of
Excellence in Paediatrics and Neuroscience and a
5.4.1.5 The future residential developments at ex-CKLKMS and YTB are under review and no estimated time of completion is available at the time of reporting. Hence, in order to adopt a worst case scenario, the developments are considered as the sensitive receivers during the operation phase only.
5.4.1.6 A planning application (Application No. A/K22/13 (Appendix 2A)) for residential development at the site was approved by the Town Planning Board in March 2012. While a detailed construction schedule for the Kerry residential development is not available, it has been advised that the residential development will be in place towards the end of 2016 (see Concurrent Project summary table in Appendix 3C).
5.4.1.7 It is understood that the conditions of the land lease have specified a requirement to provide a 20m wide waterfront promenade along the harbour front side of the site. However, as the design of the development is not fixed and, in order to provide a worst case assessment, the potential set back has not been considered in this assessment.
5.4.1.8 Thus, the two aforementioned developments, the CEP and Kerry Residential Development, are included as construction NSRs in the South Apron.
5.4.1.9 At Cha Kwo Ling, as the proposed developments in ex-CKLKMS and YTB are still in the application stage, no implementation programme is available and, as such, they are not included as NSRs during construction phase.
5.4.1.10 Table 5.5 below details the identified NSRs, both existing and future, for assessment of the construction phase noise impact. Details of the NSRs and respective photographs for the existing NSRs are presented in Appendix 5A.
Table 5.5 Representative Noise Sensitive Receivers for the Construction Phase Assessment
|
NSR |
Name |
Receiver Use |
Number of Stories |
Shortest Distance from Site (m) |
Construction Noise Assessment |
|
|
Air-borne |
Ground-borne |
|||||
|
KTD 1 |
Centre of Excellence in Paediatrics |
Future – Hospital /
Clinic |
20* |
14.5 |
ü |
-- |
|
KTD 2 |
Centre of Excellence in Paediatrics |
Future – Hospital /
Clinic |
20* |
14.5 |
ü |
-- |
|
KER 1 |
Future Development at Kerry Godown |
Future – Residential |
N/A** |
34.1 |
ü |
ü |
|
CKL 1 |
|
Existing – Public
Worship |
1 |
216.5 |
ü |
-- |
|
CKL 2 |
|
Existing – Public
Worship |
1 |
233.4 |
ü |
-- |
|
CKL 3 |
Village House 26E |
Existing –
Residential |
2 |
255.7 |
ü |
-- |
|
CKL 4 |
Village House 121 |
Existing –
Residential |
2 |
55.1 |
ü |
ü |
|
CKL 5 |
Village House 103 |
Existing –
Residential |
2 |
76.0 |
ü |
-- |
|
CKL 6 |
|
Existing –
Residential |
7 |
97.5 |
ü |
-- |
|
CKL 7 |
|
Existing –
Residential |
7 |
107.6 |
ü |
-- |
Reference is made to OZP S/K22/4 (Figures 9.5.1 to 9.5.6).
Note:
* For future NSRs assigned for the construction airborne noise impact in addition to operation phase traffic noise, in the absence of fixed development designs, the number of floors have been calculated assuming the NSRs would be built to the maximum allowable elevation designated by the OZP No. S/K22/4 and assuming a height of 2.8m per floor.
** For NSRs assigned for construction air-borne and ground-borne noise assessments, the assessments have been performed at lowest occupied floor as a worst case scenario and estimation of the number of stories is not required for these NSRs.
5.4.2 Operational Phase
5.4.2.1 Representative existing and planned future NSRs for the operational phase noise assessment have been identified at both the South Apron and Cha Kwo Ling. The selected NSRs for the operational phase are shown in Figures 5.2a and 5.2b and summarised in Table 5.6 below. Further details of the NSRs are presented in the following sections.
5.4.2.2
As part of the Kai Tak Development, there are numerous NSRs planned for
development within the former
5.4.2.3 In respect of the fixed plant air-borne noise impact during the operational phase, four NSRs have been identified within 300m of the west ventilation building on the South Apron and are also shown in Figure 5.2a. Considering the Trunk Road T2 is anticipated to reach an annual average daily traffic flow in excess of 30,000 in 2036, it is considered to be an influencing factor to the NSRs. In addition to Trunk Road T2, the future Central Kowloon Route and the Kwun Tong Bypass are, also, significant influencing factors and, hence, the Area Sensitivity Ratings for both NSRs are considered to be “C”. It should be noted that Section 7.8.22 of the Schedule 3 EIA Report for Kai Tak Development has assumed that “the NSRs would be noise insulated and do not rely on open windows for ventilation”. However, the identified NSRs have been designated an ASR rating for the purpose of the fixed plant noise assessment only.
5.4.2.4 At Cha Kwo Ling, as the Trunk Road T2 is in tunnel, there are no open road sections in the Cha Kwo Ling area. Thus, there would be no traffic noise contribution from the Trunk Road T2 at the Lam Tin interchange with the Tseung Kwan O – Lam Tin Tunnel Project (TKO-LTT), as shown in Figure 5.2b. However, adjacent NSRs would still be affected by the operational noise from the fixed plant in the eastern ventilation building serving the Trunk Road T2. Within 300m of the east ventilation building, identified NSRs include the future residential developments at YTB and the ex-CKLKMS. The layouts of the YTB has been adopted from the latest Master Layout Plan in Planning Application No. A/K15/96 available on the Town Planning Board’s website (www.info.gov.hk/tpb). The layout of ex-CKLKMS is extracted from the current Planning Review of Development on the ex-CKLKMS. The proposed layouts of the developments are, also, obtained from Planning Department in December 2012 and are also shown in Figure 5.2b. As the YTB will be under direct influence from Eastern Harbour Tunnel and the ex-CKLKMS will be under direct influence from the TKO-LTT interchange, the ASRs for both areas has been assigned as “C”.
5.4.2.5 Table 5.6 below summarises the identified NSRs, both existing and future, for the assessment of the operational phase noise impacts. Details of the NSRs and respective photographs for the existing NSRs are presented in Appendix 5A.
5.4.2.6
At Cha Kwo
Ling, properties in the
Table 5.6 Representative Noise Sensitive Receivers Identified for the Operational Phase Assessment
|
NSR** |
Name |
Receiver Use |
Number of Stories Assumed in Traffic Noise Assessment* |
Influencing Factor |
ASR*** |
Shortest Distance from Site (m) |
Operation Noise Assessment |
|
|
Traffic |
Fixed Plant |
|||||||
|
KTD 1 |
Centre of Excellence
in Paediatrics |
Hospital / Clinic |
20 |
Trunk Road T2 |
C |
14.5 |
-- |
ü |
|
KTD 3 |
Centre of
Excellence in Neuroscience (G/IC Zone next
to Kwun Tong Bypass ( |
Hospital / Clinic |
20 |
Trunk Road T2 and Kwun Tong Bypass |
C |
25.3 |
ü |
ü |
|
KTD 4 |
G/IC Zone next
to Kwun Tong Bypass ( |
Hospital / Clinic |
20 |
Trunk Road T2 |
C |
26.6 |
ü |
ü |
|
KTD 5 |
G/IC Zone next
to Kwun Tong Bypass ( |
Hospital / Clinic |
20 |
Trunk Road T2 |
C |
53.6 |
ü |
ü |
|
KTD 7 |
G Zone next to Kwun Tong Bypass (Site 3B3) |
Undesignated |
14 |
Trunk Road T2 and |
C |
139.9 |
ü |
-- |
|
KTD 8 |
R3 Zone at the centre
of the former Kai Tai Runway (Site 4A1) |
Residential |
26 |
Nil |
B |
356.2 |
ü |
-- |
|
KMS 1 |
KMS Development
- Residential 1 |
Residential |
17 |
TKO-LTT |
C |
185.7 |
-- |
ü |
|
KMS 2 |
KMS Development
- Residential 2 |
Residential |
18 |
TKO-LTT |
C |
159.3 |
-- |
ü |
|
KMS 3 |
KMS Development
- Residential 3 |
Residential |
18 |
TKO-LTT |
C |
155.5 |
-- |
ü |
|
YTB 1 |
YTB Development - Hotel 1 |
Residential |
14 |
Eastern Harbour Tunnel |
C |
284.5 |
-- |
ü |
|
YTB 2 |
YTB Development - Hotel 2 |
Residential |
14 |
Eastern Harbour Tunnel |
C |
279.8 |
-- |
ü |
|
YTB 3 |
YTB Development - Hotel 3 |
Residential |
16 |
Eastern Harbour Tunnel |
C |
272.7 |
-- |
ü |
|
YTB 4 |
YTB Development - Hotel 4 |
Residential |
18 |
Eastern Harbour Tunnel |
C |
274.1 |
-- |
ü |
|
YTB 5 |
YTB Development - Hotel 5 |
Residential |
21 |
Eastern Harbour Tunnel |
C |
279.8 |
-- |
ü |
Reference is made to OZP S/K22/4 and S/K15/19.(Figure 9.5.1 to 9.5.6)
Notes:
* For NSRs assigned for the operation phase traffic noise, in the absence of fixed development designs, the number of floors have been calculated assuming the NSRs would be built to the maximum allowable elevation designated by the latest OZP (Figure 9.5.1 to 9.5.6) and assuming 2.8m per floor; and
For NSRs assigned for the fixed plant noise assessment only, the assessment has been made at the lowest occupied floor as a worst case scenario and, hence, the number of stories is not required.
** NSR KTD 2 is located more than 300m from the western ventilation building on the South Apron and, therefore, operational phase noise impacts have not been assessed at this NSR.
** Note that NSR reference KTD 6 is not used in this EIA.
*** Designation of ASRs are only for the purpose of fixed plant air-borne noise assessment.
5.5 Identification of Potential Noise Impacts
5.5.1 Construction Phase
Overview
5.5.1.1
The potential source of noise impact during the construction phase of
the Trunk Road T2 would be the use of PME for various construction
activities. As broadly indicated in the
construction programme (Appendix 3A), the construction of the Trunk
Road T2 would be tentatively commences in December 2015 to the end of 2020, for
commissioning in 2021. The key elements
involving construction activities to be carried out at ground surface relevant
to the construction air-borne noise assessment include:
· construction of at-grade and depressed roads at the South Apron;
· cut and cover tunnels sections at the South Apron and Cha Kwo Ling;
· launching and receiving shafts for the TBM at the South Apron and Cha Kwo Ling respectively;
· TBM tunnelling from the South Apron and Cha Kwo Ling; and
· construction of two ventilation buildings. It should be noted that the administration building required for the tunnel operations is proposed to be shared with the TKO-LTT tunnel project and, as this building is being constructed by the TKO-LTT proponent, the potential impacts of its construction and operation have been assessed in the TKO-LTT EIA Report and not covered here.
5.5.1.2
These activities have the potential to cause air-borne noise disturbance
to the NSRs in the area during the construction phase. In addition, the sub-marine tunnel is
proposed to be construction using the TBM method (Section 2) and, therefore, these tunnelling works have the
potential to cause construction ground-borne noise impacts to nearby NSRs.
5.5.1.3
Figures showing the locations of respective
notional sources and notional source distances for the NSRs adopted in the
assessment are given in Appendix
5B. Further details on the construction
activities, programme and equipment are provided below.
At-grade
Road
5.5.1.4
An approximately 80m long section of at-grade road will be constructed
on the South Apron. The at-grade road
section is shown as “Sec B1” in Appendix 5B.
Breaking of existing paved road surface, excavation and construction of
utilities and road surfacing will be carried out along this section.
Depressed
Road
5.5.1.5
Following the at-grade road section on the South Apron there will be a
200m long section of depressed road. The
depressed road section is shown as “Sec B2” and “Sec B3” in Appendix 5B.
Breaking of existing paved road surface, sheet piling, excavation and
construction of road surfaces will be carried out along this section.
Cut
and Cover Tunnels
5.5.1.6
Then, following the depressed road section there will be a 500m of cut
and cover tunnel and a further 70m section at Cha Kwo
Ling. The cut and cover tunnel at Cha Kwo Ling, also, serves as a receiving pit for the TBM. The section at the South Apron is proposed to
be constructed in a two stage approach to allow traffic to run above the Trunk
Road T2 alignment during the open cut activity.
After construction of the first cut and cover cell is completed,
construction of the second cell on the opposite side of road will
commence. The section at Cha Kwo Ling would be constructed in one phase, but back
filling will only commence after the completion of TBM tunnel and the TBM is
retrieved. The cut and cover tunnel
section at the South Apron is shown as “Sec C” while the cut and cover tunnel
at Cha Kwo Ling is collectively shown as “Receiving
Pit” in Appendix 5B.
TBM
Tunnel
5.5.1.7
There will be a 2.1km of sub-marine tunnel linking the south apron and Cha Kwo Ling. As discussed in Sections 2 and 3, the tunnel section of
Trunk Road T2 will be constructed by TBM.
During TBM boring, construction ground-borne noise would be generated
that could affect the nearby NSRs and will be assessed.
Launching
Shaft and Receiving Shaft of the TBM
5.5.1.8
As the tunnel section of Trunk Road T2 will be constructed by TBM, a launching
shaft and a receiving shaft will be required.
The launching shaft will be located on the South Apron, close to the
seawall, as shown in Figure 3.6.
The receiving shaft will be located at the former PCWA
in Cha Kwo Ling, Figure 3.7.
These works areas are, also, shown in Appendix 5B as “Launching Shaft” and
“Receiving Shaft” respectively. As the
launching shaft will, also, serve as the muckout
point for the tunnelling material, there will potential for construction noise
impacts during excavation and the whole TBM boring stage. At the receiving shaft, construction noise
impact would originate from excavation of the shaft and retrieving and
dismantling of the TBMs.
5.5.1.9
It should, also, be noted that the launching shaft
is located within close proximity of the future residential development at
Kerry Godown.
However, as the tunnel level does not reach the rock head, the excavation
only reaches the Completely Decomposed Granite (CDG) layer, and hence the
ground-borne noise induced by the Powered Mechanical Equipment (PMEs) during
excavation would be anticipated to be minimal.
Therefore, construction ground-borne noise generated from PMEs during
excavation of the launching and receiving shafts are not assessed.
Ventilation
Buildings
5.5.1.10
There will be two ventilation buildings required for the tunnel section
of the Trunk Road T2. The west
ventilation building will be located on the South Apron as shown in Figure 3.4 and detailed in Appendix 5B.
The east ventilation building will be located at Cha Kwo
Ling on top of the portal of the Trunk Road T2 at the TKO-LTT interchange (Figure 3.4 and Appendix 5B)
5.5.1.11
It should be noted that although at Cha Kwo Ling, construction works from the seawall to the portal
and onwards are not assessed in this EIA and will be covered by the TKO-LTT
EIA, construction works of the east ventilation building, and operational phase
impact, will be assessed in this EIA report.
Key
PMEs Identified as Major Noise Sources
5.5.1.12
The key PMEs that would result in elevation of construction noise impact
at various works sites are shown in Table 5.7 and these are considered to be
the dominant noise sources.
Table 5.7 PMEs Identified as Major Noise Sources
|
Name
of PMEs |
SWL
of the PME, dB(A) |
|
Breaker, Excavator Mounted (Hydraulic) |
122 |
|
Dump Truck, gross vehicle weight > 38
tonne |
117 |
|
Rock Drill, Hand-held (Pneumatic) |
116 |
|
Poker, Vibratory, Hand-held |
113 |
|
Cutter circular, steel (electric) |
112 |
|
Crane, Mobile/Barge Mounted (diesel) |
112 |
|
Excavator/Loader, Wheeled/Tracked |
112 |
|
Drop hammer driving steel sheet pile |
129 |
|
Breaker, Excavator Mounted (Hydraulic) |
122 |
|
Dump Truck, gross vehicle weight > 38
tonne |
117 |
5.5.2 Operational Phase
5.5.2.1 During operational phase, potential noise impacts would be dominated by traffic noise from the open sections of the Trunk Road T2 and the other major existing roads in the area. In terms of the Cha Kwo Ling end of the alignment, the Trunk Road T2 will be entirely in tunnel, linking to another small section of tunnel to be constructed under the TKO-LTT project before surfacing at the portal at the Lam Tin Interchange, all part of the TKO-LTT project. As such, the Trunk Road T2 does not have any above ground roads in this area and, therefore, no operational traffic noise impacts on NSRs within the 300m study area would occur from this project in the south-eastern end of the study area and this area is, therefore, no considered further.
5.5.2.2 As much of the Trunk Road T2 project is in tunnel which is not a noise source, the 300m study area has been defined as 300m from the open road sections of the project which are restricted to the South Apron.
5.5.2.3
Operational noise impacts are, also, possible from
the fixed plant of the two proposed tunnel ventilation buildings. The western ventilation building will be
located on the South Apron as shown in Figure
3.4 and
detailed in Appendix
5B. The eastern ventilation building will be
located at Cha Kwo Ling on top of the portal of the
Trunk Road T2 at the TKO-LTT interchange, as, also, shown in Figure
3.4 and
detailed in Appendix
5B. The operational noise impacts at nearby NSRs
have been assessed.
5.6.1.1 A summary of potential projects that will be concurrent to the Trunk Road T2 during the construction and/or operational phase is provided in Appendix 3C. Within 300m of the project boundary of the Trunk Road T2, cumulative impacts may arise from the concurrent projects discussed below.
Kai
Tak Development
5.6.1.2 Construction works for the Kai Tak Development (KTD), and the regional delivery roads D3 and D4 are scheduled to be completed by end 2017 while D3a and D4a, are scheduled to be completed by December 2016. Hence, cumulative construction air-borne noise impacts could occur between December 2015, when the Trunk Road T2 commences construction, and December 2016. However, according to the approved KTD EIA Report, there are no identified NSRs on the South Apron during the construction of the aforementioned projects and no construction details are available. Thus, no cumulative construction noise assessment for KTD has been undertaken.
5.6.1.3 During the operational phase, cumulative traffic noise impacts are anticipated. The respective road alignments, traffic flow data and respective mitigation measures have been obtained from the Schedule 3 EIA Report reference EIA-157/2008 (Agreement No. CE 35/2006 (CE) Kai Tak Development Engineering Study cum Design and Construction of Advance Works – Investigation, Design and Construction Environmental Impact Assessment Report, approved on 4 March 2009). Cumulative traffic noise from the KTD, has, therefore, been assessed. However, there are no fixed plant sources in the KTD identified within 300m of the identified NSRs, and, therefore, no cumulative operational fixed plant noise will respect to the KTD has been assessed.
Central
5.6.1.4 Construction works for the Central Kowloon Route (CKR) are anticipated to be carried out between January 2015 and December 2020, although only works area S37 and S38 of East Portion of the CKR falls within the 300m of the Trunk Road T2 as per the latest Draft EIA Report. Nevertheless, construction works at S37 and S38 will commence at June 2015. Hence, cumulative construction noise impacts could occur between December 2015, when the Trunk Road T2 commences construction, and December 2020. However, there are no identified NSRs within the 300m study area of the construction works identified by the draft CKR EIA Report, and hence, no cumulative construction noise assessment is done.
5.6.1.5
Operationally, cumulative
traffic noise impacts from the concurrent operation of CKR and Trunk Road T2
are anticipated. Therefore, the
respective road alignments within 300m study area of the Trunk Road T2, and respective mitigation measures have been obtained
from draft CKR EIA Report (Agreement No. CE 43/2010 (HY)
5.6.1.6 It should be noted that the aforementioned draft CKR EIA Report has not been approved under the EIAO but represents the best available information at the time of reporting for this Trunk Road T2 EIA report.
Tseung
Kwan O – Lam Tin Tunnel
5.6.1.7 Construction works for the TKO-LTT are anticipated to be carried out between January 2016 and December 2020. Hence, potential cumulative construction noise impacts are anticipated for the whole Trunk Road T2 construction period from December 2016 to December 2020 and cumulative impacts with respect to construction airborne noise have been assessed. NSRs CKL 1 and CKL 4 have been identified as the concurrent NSRs for construction airborne noise impact. For cumulative construction noise impacts from the TKO-LTT project, relevant noise impact data has been obtained from draft EIA Report (Tseung Kwan O – Lam Tin Tunnel and Associated Works – Investigation, dated January 2013).
5.6.1.8 In addition, during the operational phase, concurrent fixed plant noise impacts as a result of the TKO-LTT project have been assessed. The TKO-LTT tunnel will comprise three sources of potential fixed plant noise within close proximity to the Trunk Road T2 eastern ventilation building: a sewage pumping station, a drainage pumping station and one ventilation building. However, the ventilation building falls outside 300m of the study area of the identified future NSRs, and, hence, has not been included in this assessment. Noise emissions data from the fixed plant have been extracted from the draft TKO-LTT EIA Report for the cumulative fixed plant noise assessment. As for cumulative operational traffic noise, since the Trunk Road T2 does not comprise any open road sections in the CKL area, there would be no traffic noise contribution from the Trunk Road T2 and, thus, no cumulative traffic noise impact with respect to the TKO-LTT has been undertaken.
5.6.1.9 It should be noted that the aforementioned draft TKO-LTT EIA Report has not been approved under the EIAO but represents the best available information at the time of reporting for this Trunk Road T2 EIA report.
Centre
of Excellence in Paediatrics
5.6.1.10 Construction works for the Centre of Excellence in Paediatrics (CEP) is anticipated to be carried out between September 2013 and June 2017. Hence, cumulative construction noise impact is anticipated from December 2015 to June 2017. However, during this overlapping period, there are no identified NSRs within the 300m study area of the construction works, and hence, no cumulative construction noise assessment for the CEP has been undertaken. The CEP is, however, identified as a future NSR during both construction and operational phase as it is anticipated to be operational in the middle of 2018.
Other
Lands Proposed for Hospital Use
5.6.1.11 There are in total four hospitals proposed to be established at the South Apron as discussed in Section 5.4.1.4. Except for the CEP, which has a scheduled plan for establishment, as noted in Section 5.6.1.10 above, the CEN, NAH and the future KTD private hospital are all still in the planning stage and no construction or operational schedules are available. Notwithstanding, it is assumed that the developments will be present during the operational phase of the Trunk Road T2, after 2021. However, no cumulative construction noise assessment for the CEN, NAH and the future private KTD hospital has been undertaken.
Roads
L10 and L18
5.6.1.12 Construction works for the Roads L10 and L18 are anticipated to be carried out between August 2019 and May 2020. Hence, cumulative construction noise impacts could occur from August 2019 onwards. However, the only construction site within the 300m study area of the identified NSRs on the South Apron is that for the Road L18. The only identified NSR is KTD 1 and cumulative impacts at this NSR have been assessed. Nevertheless, both L10 and L18 road sections are included in the cumulative traffic noise assessment for the operational phase.
5.6.1.13 The construction schedule for the following projects are scheduled to be completed before the commencement of the Trunk Road T2 works in December 2015 and, therefore, have been excluded from the cumulative construction noise assessment:
· Site Formation for Kai Tak Cruise Terminal Development (Stage 1);
· Site Formation for Kai Tak Cruise Terminal Development (Stage 2);
· Kai Tak Development – Advance Infrastructure Works for Developments at the Southern Part of the Former Runway (Stage 1);
· Kai Tak Development – Construction of Road D3A & D4A;
· District Cooling System at the Kai Tak Development - Phase 1;
· District Cooling System at the Kai Tak Development - Phase 2;
·
Installation of Submarine Gas
Pipelines and Associated Facilities from To Kwa Wan
to North Point for
·
Provision of Interception
Facilities at
5.6.1.14 In respect of the following potential concurrent projects, as there are no identified NSRs within the 300m study area of the proposed construction works, a cumulative construction noise assessment has not been undertaken:
· Construction of Road D3 – Section of Road D3 in North-western direction to taxiway bridge;
· Construction of Road D3 & D4 – Section of Road D3 in South-eastern direction to taxiway bridge;
· Road D1 and Associated Infrastructure Works;
· Road L9 & L16 Entrustment works to SCL;
· Kai Tak Development – Reconstruction and Upgrading of Kai Tak Nullah project;
· Construction of Road D2 & associated Works;
· Multi-purposed Stadium Complex;
· Shatin-to-Central Link (Tai Wai to Hung Hom Section);
· Shatin-to-Central Link (Hung Hom to Admiralty Section);
· Wai Chai Development Phase II (WDII);
· Kwun Tong Typhoon Shelter Improvement Works - 600m runway opening;
· Junction Improvement Works;
· Extension of Existing Footbridge FB-02; and
·
Proposed
5.6.1.15 In addition, due to a lack of project details including design, programme and engineering information, the following concurrent projects have not been included in the cumulative noise assessment for both the construction and operational phases:
· District Cooling System at the Kai Tak Development - Phase 3;
·
the Centre of Excellence in
Neuroscience and the
· Hospital development located at Site B of 3C-1;
· Proposed Foot Bridges FB-03 and FB-04 and two further footbridges identified in the OZP but as yet undesignated.
· Kai Tak Development - Waterfront Promenade fronting the CEP;
· Container Terminal 10 (CT10) Development;
·
· Proposed Ex CKL PCWA Advance Promenade; and
· Planned Residential Developments in CKL/YT and TKO.
5.6.1.16 Table 5.8 provides a summary of all identified concurrent projects within the 300m study area included in the cumulative impact assessment with the Trunk Road T2.
Table 5.8 Identified Concurrent Projects and Aspects of Cumulative Impacts
|
Name of Concurrent Projects |
Included in Noise Assessment |
|||
|
Future NSRs |
Construction Phase |
Operation Phase |
||
|
Air-borne |
Fixed Plant |
Traffic |
||
|
Central |
-- |
-- |
-- |
ü |
|
Tseung
Kwan O – Lam Tin Tunnel |
-- |
ü |
ü |
-- |
|
Centre
of Excellence in Paediatrics |
ü |
-- |
-- |
-- |
|
Kerry
Godown Residential Development |
ü |
-- |
-- |
-- |
|
Road
L18 |
-- |
ü |
-- |
ü |
|
Road
L10 |
-- |
-- |
-- |
ü |
5.7 Construction Phase Assessment Methodology
5.7.1 Construction Air-Borne Noise
Background
5.7.1.1 Construction noise impacts have been assessed by adopting standard acoustic principles and the methodologies described in the relevant TMs issued under the NCO. The SWLs of the PME were taken from Table 3 of the GW-TM or Quality Powered Mechanical Equipment (QPME) Inventory provided by EPD. Where no SWL is given in the above mentioned sources, reference has been made to the British Standard 5228: Part 1:2009 Noise Control on Construction and Open Sites and previous similar studies or from other EIA reports or measurements taken in other relevant studies.
5.7.1.2
Groups of PME have been assigned to
various construction activities of the Trunk Road T2 project and the plant
inventory is presented in Appendix 5C.
The plant inventory for the Trunk Road T2 project has been confirmed as
being practical and adequate for completing the construction works within the
scheduled timeframe. The plant inventory
has been provided as one option which is considered technically feasible, and
would represent a realistic worst-case scenario for assessment purposes. It should be noted
that in construction phase, contractors may suggest alternate PMEs of different
model given in the plant inventory.
However, the alternate PME proposed should have similar sound power
level of the assessed PME in the proposed plant inventory.
5.7.1.3 As the works involve deep excavations, some of the PMEs would operate below ground level and would not be in operation until a certain depth of excavation would be reached. Hence, for PMEs working within a trench, a -10dB(A) attenuation has been added to take account of the PMEs being out of the line of sight of the NSRs. Other PMEs are assumed to be located at ground level throughout the construction works.
5.7.1.4 In respect of construction of the TBM tunnel, noise impact from the PMEs within the tunnel is considered to be fully contained by the tunnel structure and, therefore, a -25dB(A) attenuation has been added to take account of the PMEs working within the tunnel.
5.7.1.5 It is assumed for the assessment that construction activities for the Trunk Road T2 project will be undertaken during the daytime working hours of 0700 to 1900 hours on any day not being a Sunday or public holiday.
5.7.1.6 Any critical exceedance periods and associated construction activities will be identified. Any necessary and practicable construction air-borne noise mitigation measures including movable barriers, enclosures, quieter alternative methods, re-scheduling and restricting hours of operation of noisy tasks will then be recommended if exceedances of the relevant criteria are predicted.
Construction Works Assessed
5.7.1.7 There are a total of 14 main construction works activities considered in the construction noise assessment. The construction plant inventory for the construction works are listed in Appendix 5C and are briefly presented as follows:
· Mobilisation: Including transportation of PMEs to the construction works sites for preparation of construction works;
· Site Investigation: Including the drilling of inspection holes to obtain the exact ground information including the composition of fill and location of rock head;
· TBM Works: Including the operation of supporting PMEs for the TBM at the launching shaft at Works Area WA2 at the South Apron. Since the TBM boring works will be carried out underground majority of the works will have no construction airborne noise impact;
· TBM Launching Shaft (CH6559 - CH6629): Including the excavation and backfilling of the assess shaft for the TBM at WA2;
· Cut-and-Cover Tunnel Section (CH6050 - CH6559): Similar to Launching Shaft, this construction works will cover the excavation of the tunnel section and the backfilling of the cut-and-cover section. Excavation will be carried out at one side of the Trunk Road T2 before commencing the excavation for the other side. This will allow traffic be going above the unexcavated/finished section during the cut-and-cover operation;
·
· Depressed Road Section (CH5880 - CH6050): including breaking of existing road surface, sheet piling, ELS, and structure construction;
· At-Grade Road Section (CH5250 - CH5880): Including breaking of existing road surface, construction of utilities and road surfacing will be carried out;
· TBM Reception Shaft at Cha Kwo Ling (CH8680 - CH8767): Similar to the Launching Shaft at the South Apron, Reception Shaft responsible for retrieving the TBM at the Cha Kwo Ling waterfront. The construction method would be similar to the Launching Shaft;
· Site Formation works at Cha Kwo Ling waterfront: Including the site preparation, construction of site office at the Cha Kwo Ling waterfront, also known as WA5.
·
· Barging Point construction at the South Apron: A barging point is required at the South Apron for the delivery of C&D Material and tunnel segments for the TBM works. General PMEs are required including cranes and hand-held breakers;
· Export existing fill material from Works Area WA4: WA4 is the stock piling area during the cut-and-cover operation. An excavator will be located at the works area for delivering the spoils, while excessive spoils will be transported to the barging points by dump trucks through a haul road; and
· Traffic control and surveillance system (TCSS), finishes, installation of signage, road painting and surfacing works: These are the final finishing works required before the operation of Trunk Road T2. General PMEs for road works will include paint line markers, asphalt pavers and road rollers will be required.
· There are a total of 5 Works Areas, namely WA1 to WA5, proposed for use by the Trunk Road T2 project, as discussed in Section 3 and described in Table 3.1. Works Areas WA2, WA4 and WA5 have been discussed in the above sections. WA1 will be used as storage of PMEs, plant maintenance and site offices, therefore, no significant construction noise sources would be generated from WA1. WA3 will be used for temporarily stockpiling excavated materials from the TBM operations over night that cannot be removed by barge during the daytime. During the daytime, the stockpiled material is proposed to be removed to the barging point via conveyor belts. The conveyor belt is proposed to be fully enclosed to avoid dust and noise emissions and, therefore, potential noise impacts from this source would not be considered to be significant and, hence, no construction noise assessment has been undertaken for WA3.
5.7.2 Construction Ground-Borne Noise from TBM
Background
5.7.2.1
The ground-borne noise
from the TBM activities has been assessed at identified representative NSRs as
discussed in Section 5.4.
Normal working hours for the above ground works have been defined as
0700 to 1900, as detailed in Section
3.3.1.6. While it is proposed that
the TBM works may be undertaken 24 hours per day, the feasibility of such works
would be subject to a future CNP application under the Noise Control Ordinance,
and as such, the ground-borne
noise assessment during restricted time periods has not been undertaken in this
EIA Report.
5.7.2.2
A worst case scenario along the Trunk Road T2 alignment will be assumed
for the projection of ground-borne noise.
The methodology to be adopted for assessment is recommended in The
Transit Noise and Vibration Impact Assessment (Ref 1) published by U.S.
Department of Transportation Federal Transit Administration (FTA) (FTA Guidance
Manual). This methodology has been
previously adopted for ground-borne noise assessment in the approved West
Island Line (WIL), Kowloon Southern Link (KSL) and Shatin
to Central Link (SCL) EIA Studies. The
empirically based prediction model used to predict noise levels within the
representative NSRs adopts the following equation:
L = FDL + LSR + BCF + BVR + CTN + SAF
Where:
L : ground-borne noise level within the structure, dB re: 20μPascal
FDL : force density level for the TBM in rock, mixed face or soil, dB re: 1N/m0.5
LSR : unit force incoherent line source response for the ground, dB re: 10-9 (m/s)/(1N/m0.5)
BCF : vibration coupling loss factor between the soil and the foundation, relative level
BVR : building vibration reduction or amplification within a structure from the foundation to the occupied areas, relative level
CTN : Conversion from floor and wall vibration to noise, dB re 10-9m/s to 20μPascal
SAF : Safety margin to account for project uncertainties
Ground-Borne Noise Level
within the Structure (L)
5.7.2.4
TBM-induced ground-borne noise would have an impact based upon
frequencies of, conservatively, up to about 160Hz and 500Hz for tunnels
situated in soil and rock respectively.
Above these frequencies, the material attenuation of the ground would
reduce the amplitude of the propagating waves below which there would be adverse
impact. Thus, ground-borne noise levels
will be presented in 1/3 octave bands over the frequency range of 12.5Hz to
500Hz.
Force Density Level (FDL)
5.7.2.5
The FDL values to be adopted for this Trunk Road T2 ground-borne
assessment have been obtained from vibration measurements taken during the pass-by
of a tunnel boring machine operating in soil and rock along the MTR Lok Ma Chau (LMC) Extension. Measurements were performed underground at
that time in an access shaft adjacent to the alignment at a 7m setback from the
tunnel centreline. The associated line
source response (LSR) obtained from surface and borehole impact tests were,
also, performed on similar soil and rock geology. On the assumption of a TBM source length of
10m, the F9DL values in soil and rock are shown in Figure 5.3.
5.7.2.7
The above formula is derived with reference to the following technical
papers:
· Wilson Ho, Alan Crockett and Andy Raine, Measurement and Prediction of Groundborne Noise and Vibration from a Tunnel Boring Machine, Technical Acoustics, Vol.25 No.6, December 2006); and
· Ken K.F. Kwok, Andy Raine, Banting Wong and Wilson Ho, Ground-borne Noise and Vibration Impact from Rock Tunnel Boring Machines, Hong Kong Tunnelling Conference 2009, pp147-157).
5.7.2.8
A comparison of the two TBM specifications is shown in Table 5.9 below.
Table 5.9 Comparison of TBM Specifications
|
TBM
Parameter |
TBM
LMC |
Trunk
Road T2 TBM |
|
Excavation Mode |
Earth
Pressure Balance |
Slurry
TBM |
|
Excavation Diameter |
8.75m |
14m |
|
Net Thrusting Force excluding Earth and
Water Pressure |
1953
Tonnes |
3000
Tonnes |
|
|
0
– 3 RPM |
0
– 3 RPM |
|
Total Power of Rotation Motors |
3000
kW |
5000
kW |
Line Source Response (LSR)
Where:
s = perpendicular setback;
d = depth to top of rail;
l = TBM excitation source length taken as 10m; and
f = 1/3 octave band frequency.
5.7.2.10
Given that the PSR would be along the alignment, the LSR would follow
directly by incoherent integration of the PSR values. However, the determination of the PSR for
force point impacts along the alignment over the length of the alignment is
neither practical nor affordable. For
example, at underground sections, force impacting would have to be performed in
numerous boreholes drilled to the depth of the alignment and closely spaced
along the alignment. Thus, certain
assumptions are invoked, which allow one PSR to be taken as representative
along the alignment near a building receiver and to be used in the
determination of the LSR. These
assumptions include:
· ground is layer-wise homogeneous; and
· ground is transversely isotropic along the alignment over the length of the train.
5.7.2.12
LSR has already been measured in
5.7.2.13
The PSR of WIL borehole D012 has been selected for use in this
assessment, as shown in Figure 5.4.
The ground conditions at the WIL borehole D012 and at the selected Trunk
Road T2 NSRs are compared in Table 5.10 below. Geological profiles at the two NSRs are
provided in Appendix 5D for reference.
Table 5.10 Comparison of Ground Conditions at WIL D012 and at Trunk Road T2 NSRs
|
Parameters |
Trunk Road T2 NSR - Kerry Godown Residential Development |
Trunk Road T2 NSR - Cha Kwo Ling
No.121 |
WIL Borehole D012 |
|
Geology |
Soil above Rockhead |
Soil above Rockhead |
Soil above Rockhead |
|
Rockhead Depth |
45m |
30m |
30m |
|
Tunnel
Centre Depth |
31m |
26m |
Borehole Impact Depth 18m |
5.7.2.14
For both the NSRs and WIL D012, the excitation source is located in soil
which is 4 to 14m above the rockhead level. For all the three cases, vibration would mainly
propagate in soil strata, with some reflection from the rockhead
level, so borehole WIL D012 is considered to be relevant to this
assessment. However, a safety factor is
proposed to be adopted to take account of the variations in ground conditions.
Soil Damping
5.7.2.15
The effect of
soil damping has been intrinsically included in the Line Source Response
discussed in the previous section. A
separate term on soil damping, therefore, need not be considered.
Building Coupling Factor (BCF)
5.7.2.16
In general, larger and heavier structures have greater vibration
attenuation than smaller and lighter structures. The recommended practice established within
the FTA Manual has been followed in this respect. Receivers in this study have ben divided into 5 types according to their structures and
each would have different BCF attenuations as below:
· Type 1 – Single family detached residences;
· Type 2 – 1-2 storeys complexes;
· Type 3 – 2-4 storeys medium sized structures;
· Type 4 – Large masonry building on spread footings; and
· Type 5 – Large masonry building on piles.
5.7.2.17
Figure 5.5 presents the BCF for different types of structure and indicates that
larger and heavier structures have greater vibration attenuation than smaller
and lighter structures. In fact, the
extent of the attenuation is governed by the difference in mechanical impedance
between the soil and the foundation, with impedance being determined by
differences in mass and stiffness within the soil and foundation. For structures founded on rock and tunnel
boring in rock, there is little impedance contrast between the rock and the
foundation and, therefore, the BCF is considered to be zero for conservatism.
5.7.2.18
Type 5 BCF has been adopted for the Kerry Godown
Residential Development, while Type 1 BCF has been adopted for the Cha Kwo Ling Village House No.121.
Building Vibration Response (BVR)
5.7.2.19
The BVR is generally determined by two factors as described below:
· Resonance amplification due to floor, wall and ceiling spans: The FTA Guidance Manual indicates that the natural frequency for a light weight framed building would be in the range 15-20Hz, and for a heavy concrete floored building would be in the range 20-30Hz. It recommends that an amplification of 6dB be added in the natural frequency range. The corrections in Figure 5.6 have been adopted for all buildings, as was the case for the WIL EIA, based on an assumed spread across the natural frequency range; and
· Floor-to-floor attenuation: A floor-to-floor attenuation of 2dB reduction per floor would be assumed. Where there is a multi-floor occupancy, only the structure borne noise impact on the lowest occupied floor is considered.
Conversion to Noise (CTN)
5.7.2.20
A -27dB correction for conversion of vibration (re: 10-9m/s) in room
walls, floors and ceiling to noise (re: 20 mPa) would be assumed in this
study. This adjustment is based on a
typical residential building.
Safety Factor (SAF)
5.7.2.21
In order to tackle the problem of differences in overall predicted and
measured A-weighted noise levels, a 10dB safety factor has been adopted on top
of the best estimated A-weighted noise levels to account for uncertainty and
variation in ground characteristics and the TBM excitation forces. The same safety factor was used in the LMC,
WIL and Shatin to Central Link (SCL) EIAs.
TBM Assumptions
5.7.2.22
The following operational parameters for the TBM operation have been
assumed for the ground-borne noise assessment:
· a maximum TBM advancing speed of 2m/hour;
· a net thrusting force, excluding earth and water pressure, of 3000 tonnes;
· total power of rotation motors 5000 kW; and
· cutter head rotational speed range 0-3 RPM.
Impact Assessment
5.7.3 Level of Uncertainty
5.7.3.1 The predictions of construction noise impacts have been based on the methodologies described in the GW-TM under the NCO. The methodologies which have previously been applied in other EIA studies are generally accepted for use in assessing construction noise impact against the EIAO-TM noise criteria. In carrying out the assessment, realistic worst case assumptions have been made in order to provide a conservative assessment of potential noise impacts. The construction noise impact has, therefore, been assessed based on conservative estimates for the types of plant to be utilised and the methods of working.
5.7.3.2 There are some limitations in the approach, such as the accuracy of predictive base data for future conditions, for example, plant inventory for the proposed construction works and layout of the identified future NSRs. Uncertainties in the assessment of impacts have been considered when drawing conclusions from the assessment and worst case assessments made overall.
5.8 Operation Phase Assessment Methodology
5.8.1 Operational Traffic Noise
5.8.1.1
The EPD approved computer programme, RoadNoise 2000, has been used to model
traffic noise from the Trunk Road T2 and other road networks in the study
area. The model complies with the
Calculation of Road Traffic Noise (CRTN) developed by the UK Department of Transport.
The road traffic noise would be presented in terms of noise levels
exceeded for 10% of the one-hour period for the hour having the peak traffic
flow L10 (1hour).
5.8.1.2
Calculations of future road traffic noise have been based on the peak
hourly flows in respect of the maximum traffic projected within a 15 years period upon commencement of operation,
namely 2021, including special events if there are any. The traffic projections have taken into
account the induced traffic due to the operation of other planned roads and
future developments in Section 5.6 above.
5.8.1.3
For the worst-case scenario relating to the Trunk Road T2, future
traffic data in 2036 and latest available prevailing traffic data has been adopted in the noise
model. For the purpose of this
assessment, roads have been classified as the following categories for purpose
of road traffic noise assessment, as and shown Appendix 3D:
· New roads including Trunk Road T2 and associated slip roads, and altered roads with major modification along the alignment such as the realignment works of the NLH;
· Existing roads within 300m of the open road of the project including the roads that remain either completely unchanged or that undergo only very minor alterations; and
· Other planned roads within 300m of the project.
· unmitigated scenario at assessment year (2036);
· mitigated scenario at assessment year (2036); and
· prevailing scenario for eligibility assessment for indirect technical remedies (where applicable).
5.8.1.5
Direct technical remedies in all situations would be investigated where
the predicted traffic noise level exceeds the criteria in Table 1A of Annex 5
in the TM-EIAO by 1dB(A) or more according to the EIA study brief. Specific reasons for not adopting certain
direct technical remedies in the design to reduce the traffic noise to a level
meeting the criteria in the TM or to maximize the protection for the NSRs as
far as possible would be clearly quantified and laid down. However, if the NSRs are largely affected by
noise from other roads, direct mitigation measures are only required to reduce
the noise from the new roads to a level which is:
· not higher than the standard; and
· has no significant contribution to the overall noise from other existing roads, if the cumulative noise level, i.e. noise from the new road together with other existing roads, exceeds the standard.
· the predicted overall noise level from the new road together with other traffic in the vicinity must be above the specified noise level (e.g. 70dB(A) for domestic premises and 65dB(A) for education institutions, all in L10, 1hr);
· the predicted overall noise level is at least 1.0dB(A) more than the prevailing traffic noise level, i.e. the total traffic noise level existing before the commencement of works to construct the road; and
· the contribution to the increase in the predicted overall noise level from the new road must be at least 1.0dB(A).
5.8.1.7
The total number of existing dwellings, classrooms and other noise sensitive
developments that is qualified for ITR have been estimated as applicable.
5.8.2 Operational Fixed Plant Noise
SPL = Max SWL - DC + FC - BC
Where:
SPL : Sound Pressure Level in dB(A)
Max SWL : Maximum Permissible Sound Power Level in dB(A)
DC : Distance Attenuation in dB(A) and = 20 log D + 8
FC : Façade Correction in dB(A) and = 3dB(A)
BC : Barrier Correction in dB(A)
D : Distance in metres
5.8.2.3 Where appropriate, screening corrections from buildings or other structures and prevailing noise levels obtained by measurements (daytime, evening and night-time) have been taken into account in the noise calculations. For instance, according to the GW-TM, effective barriers could result in noise reduction of 5-10dB(A) for the fixed plant depending on the line of sight of the representative NSRs. Correction for tonality has, also, been included in accordance to IND-TM. A positive 3dB(A) has been added to predicted noise levels at the NSRs due to the façade effect.
5.8.3 Level of Uncertainty
5.8.3.1 In terms of fixed plant, an operational fixed noise assessment has been carried out by identifying the noisy plant that would cause operational fixed noise impact issues and followed a similar approach to that of the construction noise assessment. For determining the distance correction factors, exact louver location instead of notional source locations have been used to reflect a realistic scenario of the operation of the fixed plant.
5.8.3.2 For traffic noise during operation phase, assessment has been made according to the approved traffic noise modelling programme. The programme is based on the approved standard CRTN and has been widely used in traffic noise assessments of other EIA studies.
5.8.3.3 There are some limitations in the approach, such as the accuracy of predictive base data for future conditions, for example, location and specification of the fixed plant in future operation and the accuracy of traffic prediction model. Uncertainties in the assessment of impacts have been considered when drawing conclusions from the assessment and worst case assessments made overall.
5.9 Construction Airborne Noise Impact Assessment
5.9.1 Unmitigated Scenario
5.9.1.1
The maximum noise levels at the representative NSRs during the
construction phase of the Trunk Road T2 project, without noise mitigation applied, are
shown in Table 5.11
below.
The detailed calculations are provided in Appendix 5E.
Table 5.11 Maximum Noise Levels (dB(A)) during Construction without Noise Mitigation
|
NSR(1) |
Daytime Construction Noise Criteria, dB(A) |
Maximum Predicted Construction Noise Level,
dB(A) |
|
KTD 1(2) |
75 |
90 |
|
KTD 2(2) |
75 |
89 |
|
KER 1 |
75 |
88 |
|
CKL 1 |
75 |
70 |
|
CKL 2 |
75 |
69 |
|
CKL 3 |
75 |
69 |
|
CKL 4 |
75 |
83 |
|
CKL 5 |
75 |
81 |
|
CKL 6 |
75 |
79 |
|
CKL 7 |
75 |
79 |
Notes:
Numbers in bold underline (e.g. 80) signify an exceedance of the noise criteria.
(1) See Figures 5.1a and 5.1b for locations of NSRs
(2) It should be noted that since KTD 1 and KTD 2 will not be in operation until 2018, the construction noise assessment has only been undertaken from January 2018.
5.9.1.2
Without mitigation, noise impacts are predicted to exceed the relevant
criteria by up to 15dB(A). The high level of unmitigated construction
noise impacts are due to the limited separation distance between the NSRs and
the works sites. The feasibility of
providing noise reduction measures to further reduce the noise impacts has been
examined and discussed below.
5.9.2 Mitigation Measures
5.9.2.1
The results in Table 5.11
above indicate that significant construction noise impacts would be anticipated
at most of the NSRs under the unmitigated scenario. Suitable noise mitigation measures are,
therefore, required to minimise the construction noise impact. The recommended measures to be applied are
presented in Appendix 5F and include:
· Use of quiet plant as per the following list. These are capable of a between 3-14dB(A) reduction in noise;
|
PME |
Reference |
SWL, dB(A) |
|
Concrete lorry mixer |
BS
D6/33 |
96 |
|
Dump Truck, 5.5 tonne < gross vehicle weight <= 38 tonne |
CNP 068 |
105 |
|
Generator, Super Silenced, 70 dB(A) at 7m |
CNP 103 |
95 |
|
Poker, vibratory, Hand-held (electric) |
CNP 173 |
102 |
|
Water Pump, Submersible (Electric) |
CNP 283 |
85 |
|
Mobile Crane - KOBELCO CKS900 |
QPME1 |
101 |
|
Excavator, wheeled/tracked - |
QPME2 |
98 |
|
HYUNDAI R80CR-9 |
QPME2 |
98 |
· Use of temporary or fixed noise barriers with a surface density of at least 10kg/m2 to screen noise from movable and stationary plant. With reference to EIAO Guidance Note No.9/2004, noise reduction of 5dB(A) can be achieved by noise barriers for movable and stationary plant respectively;
· Use of enclosures with covers at top and three sides and a surface density of at least 10kg/m2 to screen noise from generally static noisy plant such as air compressors. With reference to EIA Guidance Note No.9/2004 this is capable of a 10dB(A) reduction of noise;
· Use of acoustic fabric for the silent piling system, drill rigs, rock drills etc. Experience from approved EIA Report for Tsim Sha Tsui Station Northern Subway (EIA 154/2008) showed that this is capable of a 10dB(A) reduction of noise; and
· Proper fitting of silencers and mufflers on the ventilation fans. Experience from approved EIA Report for Tsim Sha Tsui Station Northern Subway (EIA 154/2008) showed that this is capable of a 15dB(A) reduction of noise.
5.9.2.2
Table 5.12 below
summarises all the proposed mitigation measures to be adopted for the PMEs and
their respective reduction in noise levels during the construction noise
assessment.
Table 5.12 Mitigation Measures and Assumed Effectiveness for PMEs
|
PME |
Mitigation Measures |
Reduction
Level |
|
Air
Compressor, Air flow >10m3/min and <=30 m3/min |
Noise Enclosure |
-10 |
|
Circular
Saw, bench mounted |
Noise Enclosure |
-10 |
|
Drill rig,
rotary type (diesel) |
Acoustic Fabric |
-10 |
|
Generator,
Super Silenced, 70 dB(A) at 7m |
Noise Enclosure |
-10 |
|
Piling,
Diaphragm Wall, Bentonite Filtering Plant |
Noise Enclosure |
-10 |
|
Piling,
Diaphragm Wall, Hydraulic Extractor |
Acoustic Fabric |
-10 |
|
Piling,
vibrating hammer |
Acoustic Fabric |
-10 |
|
Water Pump
(Petrol) |
Noise Enclosure |
-10 |
|
Water
Pump, Submersible (Electric) |
Noise Enclosure |
-10 |
|
Breaker,
Hand-held. Mass >= 20 kg and <= 35kg |
Movable Noise barrier |
-5 |
|
Concrete
lorry mixer |
Movable Noise barrier |
-5 |
|
Dump
Truck, 5.5 tonne < gross vehicle weight <= 38 tonne |
Movable Noise barrier |
-5 |
|
Roller,
Vibratory |
Movable Noise barrier |
-5 |
|
Excavator,
wheeled/tracked - HYUNDAI R80CR-9 |
Movable Noise barrier |
-5 |
|
Mobile
Crane - KOBELCO CKS900 |
Movable Noise barrier |
-5 |
5.9.2.3
In addition to the mitigation measures listed
above, there are also some good site practices that can further reduce the
noise levels at NSRs. However, they are non-quantifiable
and, thus, not included in the noise level calculations. These include:
· Only well-maintained plant should be operated on-site and plants should be serviced regularly during the construction period;
· Mobile plant, if any, should be sited as far from NSRs as possible;
· Plant known to emit noise strongly in one direction should, wherever possible, be properly orientated so that the noise is directed away from the nearby NSRs;
· Use of site hoarding as a noise barrier to screen noise at low level NSRs;
· Machines and plant that may be in intermittent use should be shut down between works periods or should be throttled down to a minimum; and
· Any material stockpiles and other structures should be effectively utilised, wherever practicable, to screen the noise from on-site construction activities.
5.9.3 Mitigated Scenario
5.9.3.1
Based upon the application of the mitigation measures identified above,
the maximum noise levels at the NSRs during the various construction activities
of the alignment and with the noise mitigation applied are presented
in Table 5.13
below.
The detailed calculations are provided in Appendix 5G.
Table 5.13 Maximum Noise Levels (dB(A)) during Construction with Noise Mitigation
|
Sensitive
Receiver |
Daytime
Construction Noise Criteria, dB(A) |
Maximum
Predicted Mitigated Construction Noise Level, dB(A) |
|
KTD 1 |
75 |
74 |
|
KTD 2 |
75 |
75 |
|
KER 1 |
75 |
75 |
|
CKL 1 |
75 |
60 |
|
CKL 2 |
75 |
60 |
|
CKL 3 |
75 |
59 |
|
CKL 4 |
75 |
71 |
|
CKL 5 |
75 |
69 |
|
CKL 6 |
75 |
67 |
|
CKL 7 |
75 |
67 |
Notes: Numbers in bold underline (e.g. 80) signify an exceedance of the noise criteria.
It should be noted that since KTD 1 and KTD 2 will not be in operation until 2018, the construction noise assessment has only been performed from January 2018.
5.9.3.2
The results detailed in Table 5.13
show that the recommended mitigation measures are sufficient to reduce all
noise level at all NSRs to within the 75dB(A) noise
criteria.
5.9.4 Residual Impacts
5.9.4.1
The residual impacts refer to the net impacts after mitigation, taking
into account the background environmental conditions and the impacts from
existing, committed and planned projects.
Residual impacts associated with the construction have been assessed but
no quantification of residual impacts is required.
5.9.4.2
With the implementation of the above recommended
mitigation measures, adverse residual impacts would not
be anticipated during the construction phase.
5.9.5 Cumulative Construction Noise Assessment
5.9.5.1 All concurrent projects which may contribute to air-borne noise impacts on NSRs during their construction and operational phases have been identified in Section 3. Within 300m of the NSRs, the only concurrent construction works identified are that if Road L18 at the South Apron and the TKO-LTT at the CKL area. Construction works for the L18 are scheduled to commence in August 2019 and NSR KTD 1 has been identified as the concurrent NSR for construction airborne noise impact assessment. Construction works for the TKO-LTT are scheduled to commence in January 2016 and NSRs CKL 1 and CKL 4 have been identified as the concurrent NSRs for the construction airborne noise impact assessment.
5.9.5.2 Cumulative impact for the respective concurrent projects have been identified and assessed and have been presented in Appendix 5G. The cumulative impact assessment shows that the cumulative airborne construction noise impact at the NSRs would be within the 75dB(A) criteria and, hence, adverse cumulative impacts would not be anticipated. The summary of the cumulative noise levels are given Table 5.14 below:
Table 5.14 Cumulative Construction Noise Assessment with Concurrent Projects
|
Sensitive Receiver |
Source of Cumulative Impact |
Maximum Cumulative Construction Noise Level,
dB(A) |
Exceedance, dB(A) |
|
|
L18 |
TKO-LTT |
|||
|
KTD 1 |
ü |
-- |
74 |
0 |
|
CKL 1 |
-- |
ü |
73 |
0 |
|
CKL 4 |
-- |
ü |
75 |
0 |
Notes:
Numbers in bold underline (e.g. 80) signify an exceedance of the noise criteria.
5.10 Construction Ground-borne Noise Impact Assessment
5.10.1 Unmitigated Scenario
5.10.1.1 The predicted unmitigated ground-borne noise levels for the eastbound and westbound tunnels are presented in Table 5.15 and Table 5.16 respectively. The results show that, with a 10dB(A) prediction safety factor, the daytime noise criteria of 65dB(A) is fulfilled at all the NSRs. Detailed calculations are shown in Appendix 5H.
Table 5.15 Predicted Ground-borne Noise for Eastbound Tunnel based on 10dB(A) Safety Factor
|
NSR |
NSR Name |
Vertical Distance |
Horizontal Distance |
Slant Distance |
Predicted Ground Borne Noise Level dB(A) |
|
KER 1 |
Kerry Godown Residential Development |
31 |
15 |
34 |
51 |
|
CKL 4 |
Cha Kwo Ling No.121 |
26 |
100 |
103 |
<20 |
Note: Daytime Criteria – 65dB(A), Evening Criteria – 55dB(A) and Nighttime Criteria – 40dB(A)
Table 5.16 Predicted Ground-borne Noise for Westbound Tunnel based on 10dB(A) Safety Factor
|
NSR No. |
NSR Name |
Vertical Distance |
Horizontal Distance |
Slant Distance |
Predicted Ground Borne Noise Level dB(A) |
|
KER 1 |
Kerry Godown
Residential Development |
31 |
41 |
51 |
35 |
|
CKL 4 |
Cha Kwo Ling No.121 |
26 |
105 |
108 |
<20 |
Note: Daytime Criteria – 65dB(A), Evening Criteria – 55dB(A) and Nighttime Criteria – 40dB(A)
5.10.1.2 The predicted exceedance at the Kerry Godown Residential Development during the TBM works for the Eastbound tunnel is considered to be conservative, since a 10dB(A) safety factor has been added to the assessment predictions.
5.10.2.1 In order to ensure compliance with the daytime ground-borne noise limits, the advancing speed of the TBM should be restricted to 2m/hr. Ground-borne noise and vibration monitoring is considered as not being required.
5.10.3.1
With the implementation of the above recommended
mitigation measures, adverse residual impacts would not
be anticipated during the construction phase.
5.10.4 Cumulative Impacts
5.10.4.1 No other TBM works are proposed to be undertaken in parallel to the Trunk Road T2 works and, therefore, no cumulative impacts are predicted.
5.11 Operational Fixed Plant Noise Impact Assessment
5.11.1.1
During the operational phase, the Trunk Road T2 will require two
ventilation buildings located at the South Apron and the Cha Kwo
Ling respectively, (see Figure 3.4). These ventilation buildings will generate
operational air-borne noise through their louvers from the operation of their
ventilation fans.
5.11.1.2
Fixed plant noise assessment has been based on the
IND-TM. The assessment has been carried
out using engineering design that the SWL of the ventilation fan at the louver
would not be greater than 104dB(A). The SPLs at the identified NSRs (Figures
5.7a and 5.7b for the South Apron and Cha Kwo Ling, respectively), have been calculated with regard
to the separation distances and orientation from the NSRs, as well as
cumulative noise impacts from other fixed noise sources.
5.11.1.3
Within 300m of the identified NSRs at Cha Kwo Ling, the fixed plant that will contribute to
cumulative noise impacts have been identified as the drainage and sewerage
pumping stations of the TKO-LTT project, shown on Figure 5.7b. Other fixed plant including the ventilation
building of the TKO-LTT project, but this is located outside the 300m study
area of the NSRs and, thus, not included in the this assessment.
5.11.1.4
A summary of the cumulative operational fixed plant
noise levels are presented in Table 5.17 below and detailed calculations are presented
in Appendix 5I.
Table 5.17 Cumulative Operation Fixed Plant Noise Impact
|
NSR* |
Distance to Trunk Road T2
Louver (m) |
ASR |
Operation Noise Criteria,
ANL-5dB(A) |
Operation Fixed Plant Noise
Impact, dB(A) |
|
|
Daytime |
Night-time |
||||
|
KTD 1 |
274.1 |
C |
65 |
55 |
40 |
|
KTD 3 |
240.1 |
C |
65 |
55 |
41 |
|
KTD 4 |
143.5 |
C |
65 |
55 |
46 |
|
KTD 5 |
115.9 |
C |
65 |
55 |
48 |
|
YTB 1 |
284.5 |
C |
65 |
55 |
40 |
|
YTB 2 |
279.8 |
C |
65 |
55 |
40 |
|
YTB 3 |
272.7 |
C |
65 |
55 |
40 |
|
YTB 4 |
274.1 |
C |
65 |
55 |
40 |
|
YTB 5 |
279.8 |
C |
65 |
55 |
40 |
|
KMS 1 |
185.7 |
C |
65 |
55 |
46 |
|
KMS 2 |
159.3 |
C |
65 |
55 |
48 |
|
KMS 3 |
155.5 |
C |
65 |
55 |
48 |
Note * NSR KTD 2 is
located more than 300m from the western ventilation building on the South Apron
and, therefore, operational phase noise impacts have not been assessed.
5.11.1.5
The operation fixed plant noise impacts at the
identified NSRs have been predicted to comply with the respective criteria and
adverse fixed noise impacts are not anticipated. Therefore, no mitigation measures are
required.
5.12 Operational Traffic Noise Impact Assessment
5.12.1 Unmitigated Scenario
5.12.1.1
The predicted traffic flow figures for the noise modelling for the
prevailing year of 2008 and the worst case design year 15 years after the opening
of the Trunk Road T2 road of 2036 are detailed in Section 3 and are given in Appendix 5J. Transport Department’s approval of the
traffic figures for use in this EIA Report has been obtained and is provided in
Appendix
5K.
5.12.1.2
The L10(1hour)
noise levels in dB(A) at the representative NSRs during the operational
phase without noise mitigation measures applied are shown in Table 5.18
below. Values at every floor of each sensitive
receiver are presented and a complete set of modelling results are provided in Appendix
5L. Sample Calculation for the
NSRs are given in Appendix 5M.
Table 5.18 Predicted Unmitigated Traffic Noise Levels, L10(1 hour), dB(A), at Future Noise Sensitive Receivers in the Year 2036
|
Sensitive Receiver |
Floor |
Predicted L10 Noise for 2036 (1 hour), dB(A)* |
|
KTD1 |
1 |
76.8 |
|
|
2 |
76.8 |
|
|
3 |
76.8 |
|
|
4 |
76.8 |
|
|
5 |
76.7 |
|
|
6 |
76.7 |
|
|
7 |
76.6 |
|
|
8 |
76.5 |
|
|
9 |
76.4 |
|
|
10 |
76.3 |
|
|
11 |
76.2 |
|
|
12 |
76.1 |
|
|
13 |
76.0 |
|
|
14 |
75.9 |
|
|
15 |
75.8 |
|
|
16 |
75.7 |
|
|
17 |
75.6 |
|
|
18 |
75.5 |
|
|
19 |
75.4 |
|
|
20 |
75.4 |
|
KTD 3 |
1 |
78.5 |
|
|
2 |
79.0 |
|
|
3 |
79.4 |
|
|
4 |
79.6 |
|
|
5 |
79.6 |
|
|
6 |
79.6 |
|
|
7 |
79.6 |
|
|
8 |
79.5 |
|
|
9 |
79.5 |
|
|
10 |
79.4 |
|
|
11 |
79.3 |
|
|
12 |
79.1 |
|
|
13 |
79.0 |
|
|
14 |
78.9 |
|
|
15 |
78.8 |
|
|
16 |
78.7 |
|
|
17 |
78.6 |
|
|
18 |
78.4 |
|
|
19 |
78.3 |
|
|
20 |
78.2 |
|
KTD 4 |
1 |
76.5 |
|
|
2 |
76.6 |
|
|
3 |
76.8 |
|
|
4 |
77.0 |
|
|
5 |
77.2 |
|
KTD 4 |
6 |
77.4 |
|
|
7 |
77.7 |
|
|
8 |
77.8 |
|
|
9 |
77.9 |
|
|
10 |
77.9 |
|
|
11 |
78.0 |
|
|
12 |
78.0 |
|
|
13 |
78.0 |
|
|
14 |
77.9 |
|
|
15 |
77.9 |
|
|
16 |
77.9 |
|
|
17 |
77.8 |
|
|
18 |
77.9 |
|
|
19 |
77.8 |
|
|
20 |
77.8 |
|
KTD 5 |
1 |
77.7 |
|
|
2 |
78.2 |
|
|
3 |
78.9 |
|
|
4 |
79.5 |
|
|
5 |
79.7 |
|
|
6 |
79.7 |
|
|
7 |
79.9 |
|
|
8 |
80.0 |
|
|
9 |
80.1 |
|
|
10 |
80.2 |
|
|
11 |
80.2 |
|
|
12 |
80.2 |
|
|
13 |
80.2 |
|
|
14 |
80.1 |
|
|
15 |
80.0 |
|
|
16 |
80.0 |
|
|
17 |
79.9 |
|
|
18 |
79.8 |
|
|
19 |
79.7 |
|
|
20 |
79.6 |
|
KTD 7 |
1 |
77.0 |
|
|
2 |
77.4 |
|
|
3 |
77.7 |
|
|
4 |
78.0 |
|
|
5 |
78.2 |
|
|
6 |
78.4 |
|
|
7 |
78.4 |
|
|
8 |
78.5 |
|
|
9 |
78.5 |
|
|
10 |
78.5 |
|
|
11 |
78.4 |
|
|
12 |
78.4 |
|
KTD 7 |
13 |
78.3 |
|
|
14 |
78.3 |
|
KTD 8 |
1 |
66.4 |
|
|
2 |
66.4 |
|
|
3 |
66.4 |
|
|
4 |
66.4 |
|
|
5 |
66.5 |
|
|
6 |
66.5 |
|
|
7 |
66.5 |
|
|
8 |
66.5 |
|
|
9 |
66.6 |
|
|
10 |
66.6 |
|
|
11 |
66.6 |
|
|
12 |
66.6 |
|
|
13 |
66.6 |
|
|
14 |
66.5 |
|
|
15 |
66.5 |
|
|
16 |
66.5 |
|
|
17 |
66.5 |
|
|
18 |
66.5 |
|
|
19 |
66.6 |
|
|
20 |
66.6 |
|
|
21 |
66.6 |
|
|
22 |
66.6 |
|
|
23 |
66.5 |
|
|
24 |
66.6 |
|
|
25 |
66.5 |
|
|
26 |
66.5 |
|
|
Represents an exceedance
of the noise criteria |
|
Note*: Noise
Criteria is 55dB(A) for Hospital NSRs (KTD 1 – KTD
5) and 70dB(A) for other NSRs.
5.12.1.3
The predicted cumulative road traffic noise level for the hospital NSRs
KTD1, KTD3, KTD4, KTD5 exceed the stipulated noise criterion of 55dB(A) while
KTD7 exceed the stipulated noise criterion of 70dB(A). However, these affected NSRs will be noise
insulated and will not rely on openable windows for
ventilation. Thus, no direct mitigation
measures would be required.
5.12.2.1 Exceedances of respective operational traffic noise are anticipated at some of the NSRs. However, the affected NSRs are anticipated to be equipped with centralised air conditioning systems and will, therefore, not rely on openable windows for ventilation. Thus, no direct mitigation measures are required.
5.12.3 Residual Impacts
5.12.3.1
The residual impacts refer to the net impacts after mitigation, taking
into account the background environmental conditions and the impacts from
existing, committed and planned projects.
Residual impacts associated with the operational phase have been
assessed but no quantification of residual impacts is required.
5.12.3.2
With the implementation of centralised
air-conditioning negating the need to rely on openable
windows for ventilation, adverse residual impacts would
not be anticipated as result of operational traffic noise.
5.13 Environmental Monitoring and Audit
5.13.1.1
The assessment has concluded that impacts during the construction phase
will occur as a result of the implementation of the project and, therefore,
mitigation measures are required. As
such, it is recommended that construction phase environmental monitoring and
audit (EM&A) is undertaken to ensure that adverse impacts do not
occur. Further details of the specific
EM&A requirements are detailed in Section
12 of this report and in the EM&A Manual.
5.14.1.1
Assessments for construction airborne noise, ground-borne noise,
operation traffic noise and operation fixed plant noise have been
completed. The assessment results show
that the Trunk Road T2 project would not cause significant impacts to the
nearby NSRs with proper implementation of mitigation measures and adverse
residual impacts would not be expected. The predicted noise impact would be
unlikely to induce public health concern, unduly affect the welfare of the local
community.
5.14.1.2
For traffic noise impact, the future NSRs
identified have been confirmed as being noise insulated as per the Schedule 3 EIA Report for Kai Tak
Development and will, therefore, not rely on openable windows for ventilation and hence, no direct
mitigation measures are required.