4. NOISE IMPACT

4.1 Introduction

This section presents an assessment of the potential noise impact associated with the construction and operation of Link Roads G & L. The quantitative assessment methodology which has been adopted is presented and control measures, to ensure the effective protection of the identified sensitive receivers, are recommended.

4.2 Governmental Legislation and Standards

4.2.1 Construction Noise

The principal legislation on the control of construction noise is the Noise Control Ordinance (NCO) (Cap 400) and the Environmental Impact Assessment Ordinance (EIAO) (Cap 499). Various Technical Memoranda (TMs), which stipulate control approaches and criteria, have been issued under the NCO and EIAO. The following TMs which are applicable to the control of noise from construction activities are as follows:

· Technical Memorandum on Noise from Percussive Piling (PP-TM);

· Technical Memorandum on Noise from Construction Work other than Percussive Piling (GW-TM);

· Technical Memorandum on Noise from Construction Work in Designated Areas (DA-TM); and

· Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) Annexes 5 and 13.

4.2.2 Percussive Piling

Percussive piling is prohibited at any time on Sundays and public holidays and during the weekday evening and nighttime hours (1900 – 0700 hours, Monday through Saturday). A Construction Noise Permit (CNP) is required for such works during the periods 0700 – 1900 hours, Monday through Saturday.

When assessing a CNP application for the carrying out percussive piling, the Environmental Protection Department (EPD) uses the PP-TM as a reference. The EPD will consider the difference between the Acceptable Noise Levels (ANLs), as promulgated in the PP-TM, and the Corrected Noise Levels (CNLs) that are associated with the proposed piling activities. Depending on the level of noise impact on nearby Noise Sensitive Receivers (NSRs), the EPD may allow 3, 5 or 12 hours of piling time (see Table 4.1 below daily).

Table 4.1 Permitted Hours of Operation for Percussive Piling

Amount by which CNL exceeds ANL

Permitted hours of operation on any day not being a holiday

More than 10 dB(A)

Between 0 dB(A) and 10 dB(A)

No exceedance

0800 to 0900 and 1230 to 1330 and 1700 to 1800

(3 hours)

0800 to 0930 and 1200 to 1400 and 1630 to 1800

(5 hours)

0700 to 1900

The Government has committed to phasing out the use of diesel, pneumatic and steam hammer pile drivers, which are particularly noisy, since 1 October 1999. These pile drivers now are not permitted to be used on Government projects.

4.2.3 General Construction Works

For general construction works during normal working hours (i.e. 0700 to 1900 hours on any day not being a Sunday or public holiday) noise assessments must be made at the openable windows of buildings. The assessment procedures are defined in the EIAO-TM and the recommended noise standards presented in Table 4.2 below.

Table 4.2 EIAO-TM Daytime Construction Noise Standards (L_{eq.30 min} dB(A))

Uses

Acceptable Noise Standards

Domestic Premises

Educational institutions (normal periods)

Educational institutions (during examination periods)

The NCO provides statutory controls on general construction works during the restricted hours (i.e. 1900 – 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 would require a CNP. The EPD is guided by the GW-TM when assessing such an application.

When assessing an application for the use of PME, the EPD will compare the ANLs, as promulgated in the GW-TM, and the CNLs (after accounting for factors such as barrier effects and reflections) associated with the proposed PME operations. A CNP will be issued if the CNL is equal to or less than the ANL. 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 4.3 below.

Table 4.3 Acceptable Noise Levels (ANL, L_{eq.30 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

All days during the night-time (2300 – 0700 hours)

60 65 70

45 50 55

In addition to the general controls on the use of PME during the restricted hours, the EPD has implemented more stringent control mechanisms via the DA-TM. The DA-TM regulates the use of five types of Specified Powered Mechanical Equipment (SPME) and three types of Prescribed Construction Work (PCW), which are non-PME activities, in primarily densely populated neighbourhoods called Designated Areas (DAs). The SPME and PCW are :

SPME :

· Hand-held breaker

· Bulldozer

· Concrete lorry mixer

· Dump truck

· Hand-held vibratory poker

PCW :

· Erection or dismantling of formwork or scaffolding

· Loading, unloading or handling or rubble, wooden boards, steel bars, wood or scaffolding material

· Hammering

In an attempt to provide environmental additional protection carrying out of PCW is generally banned inside a DA. As for the use of SPME, it would be necessary to comply with DA-TM noise level requirements that are 15 dB(A) more stringent than those listed in the GW-TM before a CNP would be issued. As all sections of Link Roads G & L will be within DA, the requirements stated in the DA-TM apply to this study.

Despite any description or assessment made in the subsequent paragraphs, the Noise Control Authority will be guided by the relevant Technical Memorandum (Memorandum) in assessing an application, once filed, for a Construction Noise Permit. He will consider all the factors affecting his decision taking contemporary situations / conditions into account. Nothing in this Report shall bind the Authority in making his decision. There is no guarantee that a Construction Noise Permit will be issued. If a permit is to be issued, the Authority shall include any condition he thinks fit and such conditions are to be followed while the works covered by the permit are being carried out. Failing which will lead to cancellation of the permit and prosecution action under the NCO.

4.2.4 Operational Phase

Road Traffic Noise

Relevant criteria for road traffic noise levels at the openable windows of buildings are given in Table 4.4.

Table 4.4 EIAO-TM Road Traffic Noise Planning Criteria

Uses

Road Traffic Noise _{10, (1 hr)} dB(A)

Domestic Premises

Hotel and Hostels

Offices

Educational institutions

Hospitals & clinics

For existing NSRs that are affected by noise from “new” roads, direct noise mitigation measures should be provided as far as practicable when the predicted road traffic noise levels exceeded the relevant noise criteria.

If, after implementation of direct technical remedies, any facades of existing sensitive uses are still exposed to predicted noise levels exceeding the relevant noise criteria, provision of indirect technical remedies in the form of acoustic insulation and air-conditioning should be considered in accordance with three criterion for the Indirect Technical Remedies Eligibility Test.

(i) The predicted overall noise level from the new road, together with other traffic noise in the vicinity must be above the specified noise levels (L_{10, peak hour} 65 and 70 dB(A) for educational institutions and residential dwellings respectively);

(ii) The predicted overall noise levels is at least 1.0 dB(A) more than the prevailing traffic noise level; i.e. the total traffic noise level existing before the commencement of works to be constructed; and

(iii) The contribution to the increase in the predicted overall noise level from the new road must be at least 1.0 dB(A).

For the purpose of this Study, all roads are described as either :

· ‘existing’ which are unchanged by the proposed project except for possibly taking additional traffic; or

· ‘new’ which in the context of this report describes all roads that are completely new or are substantially altered by the proposed project (e.g. the location of the road has altered or has been widened substantially).

The ‘new’ roads adopted for this Study are the Link Roads G & L. It has been assumed that all other roads in the vicinity of Link Roads G & L such as West Kowloon Expressway and Route 9 between Tsing Yi and Cheung Sha Wan are classed as ‘existing’ roads. No policy currently exists to mitigate noise from existing roads by using direct mitigation measures in the form of roadside noise barriers and enclosures. However, direct mitigation measures will be incorporated into the new road design where necessary to mitigate any unacceptable noise levels at nearby NSRs.

Low noise road surface have been confirmed as being in place on the West Kowloon Expressway and Route 9 where speed limits are higher than 50 kph. Standard wearing course have been assumed for all other remaining roads.

4.2.5 Baseline Condition

Existing Conditions

The West Kowloon area surrounding the Link Roads G & L consists of both residential buildings and depots located to the northwest and northeast of Link Roads G & L respectively. Mei Foo Sun Chuen consists of mainly 20 storey high residential housing, Lai Chi Kok Park is located to the north of Lai Wan Interchange. In addition, plans for the KMB Bus Depot include the construction of a 40 storey building, which will be used for residential dwellings and the provision of staff quarters, located to the east of Mei Foo Sun Chuen. Also, a proposed regional stadium is located to the northwest of Lai Wan Interchange and a planned housing site, Site 10, is located on the far eastern part of Lai Wan Interchange have been identified.

The existing noise environment is dominated by road traffic. Three trunk roads, Route 3, Route 9 and West Kowloon Expressway are the major sources of roads traffic noise. Noise from the traffic mainly contributes to the daytime and nighttime background noise levels in the area.

Baseline traffic noise levels prior to construction of the new road (i.e Year 2001) will comply with the HKPSG limit of 70 dB(A). The modelling results of 2001 noise levels from the existing roads (i.e. West Kowloon Expressway) are in the range of 56.9 to 68.2 dB(A).

Future Conditions

It is expected that the road traffic from the future Route 9 and proposed Link Roads G & L will increase the ambient noise levels in the area.

4.2.6 Noise Sensitive Receivers

Existing Noise Sensitive Receivers

Representative NSRs, as defined by the EIAO-TM and NCO have been identified and their horizontal distance from the Link Roads G & L are presented in Table 4.5. Locations of the NSRs during construction phase are also shown in Figure 4.1.

Planned Sensitive Uses

Outline Zoning Plans, approved Section 16 applications and re-zoning applications which have come into effect up until 20 June 2000 within the study boundary were reviewed and confirmed with Planning Department. The planned noise sensitive receivers (NSRs) which were confirmed including West Kowloon Reclamation Site 10 which is located northeast of Lai Wan Interchange and Lai Chi Kok KMB Bus Depot were identified as NSR’s for the following assessment. Relevant correspondence is attached in Annex I for reference.

Based on the information provided by the relevant Project Architects and Planners for the planned NSRs (i.e. Housing development Site 10 and KMB bus depot CDA) it has been identified that these developments will not be occupied when Link Roads G & L is under construction and hence have not been included for the construction noise impact assessment. However, these NSRs are included in the operational noise assessment.

Table 4.5 Location of Noise Sensitive Receivers – Construction Phase

NSRs

Locations

Sensitive Uses

Buffer distance (m)

MF1

MF2

MF3

MF4

MF5

Mei Foo Sun Chuen, Phase 3, BLK 90

Mei Foo Sun Chuen, Phase 8, BLK 104

Mei Foo Sun Chuen, Phase 8, BLK 112

Mei Foo Sun Chuen, Phase 8, BLK 132

Mei Foo Sun Chuen, Phase 8, BLK 128

Residential

300

230

180

230

260

4.3 Construction Phase

Potential Source of Impacts

Various construction activities have been identified which could cause elevations in noise levels at the nearby NSRs. A typical programme for construction for Link Roads G & L has been developed which is shown in Figure 2.1. It is recognised that the Contractor may develop a different construction programme and construction method from the one presented in this report, however it will be his responsibility to demonstrate that his methods ensure compliance with the criteria stipulated in the preceding sections.

The main construction activities comprise :

· construction of road embankment;

· viaduct substructure;

· viaduct superstructure; and

· road pavement.

Construction activities for the Link Roads G & L are expected to be undertaken during normal daytime working hours (i.e. 0700 to 1900 hours on any day not being a Sunday or public holiday). According to the information provided for this Assignment, construction of Route 9 – Tsing Yi to Cheung Sha Wan and Route 16 (Alternative Alignment) – West Kowloon to Shatin will take place between 2002 and 2006 and between the end of 2003 and 2004 respectively. Therefore, construction activities for Route 9 (Tsing Yi to Cheung Sha Wan) will overlap with this project. The cumulative noise impact of Link Roads G & L and relevant component sections of Route 9 has been assessed. A plant inventory consisting of both Link Roads G & L based on previous relevant highways project experience and Route 9 based on Tables 7.3 to 7.5 of Sections 7 of approved EIA report under Register No. EIA-025/1999 “Route 9 between Tsing Yi and Cheung Sha Wan” has been established. The details are contained in Table D-1 in Annex D.

4.3.1 Assessment Methodology

A methodology for assessing construction noise other than percussive piling has followed the guidelines set out in GW-TM. The methodology is as follows :

· identify the likely type, sequence and duration of principal noisy construction activities required for the implementation of the proposed project;

· identify a list of plant inventory likely to be required for each construction activity;

· calculate the maximum total sound power level (SWL) for each construction activity using the plant list and SWL data given for each plant in the technical memorandum;

· representative NSRs as defined by the EIAO-TM have been identified, based on existing and committed landuses in the study area that may be affected by the worksite. For the purposes of this study, NSRs have been identified up to a distance of 300m from the alignment. However, this distance may be reduced, subject to the first layer of NSRs providing adequate acoustic shielding;

· calculate the distance attenuation and barrier corrections to NSRs from worksite notional noise source point; and

· predict construction noise levels at NSRs in the absence of any mitigation measures.

If the noise assessment criteria are exceeded at NSRs, mitigation measures must be considered. A re-evaluation of the total SWL for each construction activity will be made assuming the use of practical mitigation measure such as “quiet” equipment and movable noise barriers. If the criteria are still exceeded, further mitigation measures such as reduction in noisy plant working simultaneously would be considered.

4.3.2 Evaluation of Impacts

The unmitigated noise levels associated with Link Roads G & L and mitigated noise levels from Route 9 have been predicted for the worst case representative NSRs for each construction and are contained in Table E-1 (Annex E) and take account of attenuation of noise over distance.

Link Roads G & L

Table E-1 in Annex E indicates that the cumulative noise impact of both unmitigated construction activities associated with the construction of Link Roads G & L and mitigated construction activities related to the construction of Route 9, would cause exceedance of the daytime construction noise criterion at Mei Foo Sun Chuen (ie MF2 to MF4), up to 77 dB(A). Mitigation measures are therefore required for these NSRs in order to alleviate the noise impacts generated from Link Roads G & L during the construction phase.

Cumulative Noise Impacts

Based on the construction programme of Link Roads G & L given as Figure 2.1, four construction activities are likely to be undertaken. These activities include the construction of earthworks excavation and filling, viaduct substructure, viaduct superstructure and road pavement. In order to predict the noise level in worse case scenario, the cumulative effect of construction activities of both Link Roads G & L and Route 9 are assumed to be undertaken concurrently and shown in Table 4.6 below. Exceedances of the daytime construction noise criteria are predicted and mitigation measures are therefore required to alleviate the noise impacts generated from Link Road G & L.

Table 4.6 Cumulative Noise Impacts (No Mitigation Measures for Link Roads G & L ) – (L_eq.30
min dB(A))

NSR

Daytime

Construction

Noise

Criterion

Road

Embankment

Viaduct

Substructure

Viaduct

Superstructure

Road

Pavement

Noise Impact from Link Roads G & L

Noise Impact

from

Route 9

Cumulative

Impact

MF1

MF2

MF3

MF4

MF5

Table 4.7 Sound Power Levels for Specific Silenced PME

PME

BS 5228

Table no

Ref no

SWL

dB(A) max

Bulldozer

Mobile Crane

Air compressor

Concrete Pump

Dump Truck

Excavator

· for trenching

· for ground excavation

Generator

Lorry

Concrete Lorry Mixer

Asphalt Paver

Road Roller

Poker Vibrator

C.3

C.7

C.6

C.9

C.3

C.7

C.9

C.6

C.8

C.6

110

106

109

105

106

100

105

100

101

104

100

It should be noted that various types of silenced equipment can be found in Hong Kong. When processing a CNP application, EPD will apply the noise levels contained in the relevant statutory TM unless the noise emission of a particular piece of equipment can be validated by certificate or demonstration.

With quiet plant (as described in Table 4.7 above) substituted in the equipment inventories given in Table D-2 (Annex D), the cumulative noise levels of both mitigated construction activities of Link Roads G & L and Route 9 at each NSR would be shown in Table E-2 (Annex E).

Mitigation 1

Table E-2 in Annex E indicated that with the use of quiet plant under the construction of Link Roads G & L, the cumulative noise impact of construction activities from both Link Roads G & L and Route 9 would comply with the daytime construction noise criterion at Mei Foo Sun Chuen and additional mitigation measures are therefore not required for the construction activities of Link Roads G & L.

Cumulative Noise Impacts

With the use of quiet plant, the assessment indicated that the cumulative noise levels comply with the daytime construction noise criterion and additional mitigation measures are therefore not required for the construction activities of Link Roads G & L.

Table 4.8 Cumulative Noise Impacts – With use of quiet plant for Link Roads G & L (mitigation 1) – (L_{eq.30 min} dB(A))

NSR

Daytime

Construction

Noise

Criterion

Road

Embankment

Viaduct

Substructure

Viaduct

Superstructure

Road

Pavement

Noise Impact from Link Roads G & L

Noise Impact

from

Route 9

Cumulative

Impact

MF1

MF2

MF3

MF4

MF5

4.4 Operational Phase

4.4.1 Road Traffic Noise

During the operational phase, road traffic noise will be the dominant noise source within the Study Area, and will potentially affect both the existing and planned noise sensitive developments. Sources of noise are identified to be road traffic from the proposed Link Roads G & L, West Kowloon Expressway, Route 9 and its slip roads.

4.4.2 Noise Sensitive Receivers

In addition to the NSRs identified for the construction phase, the most severely impacted representative NSRs have been identified and are shown in Figure 4.2. Where applicable, the noise levels for each NSRs have been predicted at three different floor levels (low, medium and top). Representative floors and the corresponding mPD height of each NSRs are shown in Table 4.9.

Table 4.9 Location of Noise Sensitive Receivers – Operational Phase

Description

NSR 1D

Representative

Floors

Representative

MPD

Mei Foo Sun Chuen, Phase 3 (Block 90)

Mei Foo Sun Chuen Phase 8 (Block 104)

Mei Foo Sun Chuen, Phase 8 (Block 112)

Mei Foo Sun Chuen, Phase 8 (Block 132)

Mei Foo Sun Chuen, Phase 8 (Block 128)

MF1

MF2

MF3

MF4

MF5

1/F 10/F 19/F

14.7 39.9 65.1

KMB Bus Depot CDA Site (Tower 1)

KMB Bus Depot CDA Site (Tower 2)

KMB Bus Depot CDA Site (Tower 3)

KMB1

KMB2

KMB3

1/F 21/F 44/F

1/F 21/F 41/F

31.8 91.3 162.8

31.8 91.3 153.8

Description

NSR 1D

Representative

Floors

Representative

MPD

Site 10-Residential Blocks, Phase 1 (Block 3)

Site 10-Residential Blocks, Phase 1 (Block 4)

Site 10-Residential Blocks, Phase 2 (Block 5)

Site 10-Residential Blocks, Phase 2 (Block 6)

Site 10-Residential Blocks, Phase 2 (Block 7)

Site 10 - School

10S1

10S2

10S3

10S4

10S5

10S6

1/F 21/F 41/F

1/F 21/F 38/F

1/F 21/F 41/F

1/F 4/F 7/F

11 66 121

11 66 112.8

11 66 121

11.5 21.5 31.5

4.4.3 Assessment Methodology

Road traffic noise calculations have been undertaken in accordance with the UK methodology for the Calculation of Road Traffic Noise (CRTN), which is currently required by the EPD.

The road scheme within the Study Area and the surrounding road network has been divided into 453 road segments, each of which has been assigned one of 100 road layouts. A road layout defines the road width, surface type, traffic condition and if applicable, the height and locations of roadside barriers. The division of the project into segments was carried out in accordance with the CRTN procedure and the noise modelling was carried out using “roadNoise” traffic noise model, which fully implements CRTN procedures and methodologies. Hard ground, as defined in CRTN, has been assumed throughout the Study Area and all other features that may result in noise screening are defined in the model.

Direct noise mitigation measures recommended by the relevant EIA of Route 9 and based on further drawing details provided by the relevant Consultants are considered in our current noise modelling. The details are as follows and are shown in Figures 4.3(a) and (b) :

· 3m high roadside noise barrier located along the western side of the northbound carriageway of Route 9.

· 5m high roadside noise barrier located along the eastern side of the northbound carriageway of Route 9.

· 5m high roadside noise barrier located along the eastern side of the southbound carriageway of Route 9.

· Full enclosure located at northbound carriageway of Route 9 slip road.

· Semi-enclosure / Full enclosure located at southbound carriageway of Route 9 slip road.

· 3m high roadside noise barrier located on the western side of the northbound carriageway of Route 9 slip road.

· 3m high roadside noise barrier located on the eastern side of the southbound carriageway of Route 9 slip road.

· 3m high roadside noise barrier located on the western side of the northbound carriageway of Route 9 near the Lai Wan Interchange.

· 3m high roadside noise barrier located on the eastern side of the southbound carriageway of Route 9 near the Lai Wan Interchange.

· 3m high roadside noise barrier located on the northern side of the eastbound carriageway of Route 9 slip road near the Lai Wan Interchange.

· Provision of Low Noise Surfacing on the northbound main carriageway of Route 9 and its slip road (Ramp G).

Provision of Low Noise Surfacing on the southbound main carriagway and its slip road (Ramp H).

Direct noise mitigation measures of West Kowloon Expressway according to the as-built drawing records have been incorporated into the noise model. The details are shown in Figure 4.3(c) as follows :

· 3m high roadside noise barrier located on the northern side of eastbound main carriageway of West Kowloon Expressway.

· 3m high roadside noise barrier located on the northern side of westbound main carriageway of West Kowloon Expressway.

· Provision of Low Noise Surfacing on the eastbound and westbound main carriageway of West Kowloon Expressway.

Apart from the assumptions and methodologies stated above, 0.8m high parapet was assumed for the location on viaduct of Route 9, West Kowloon Highway and Link Roads G & L respectively.

In line with CRTN procedures and in order to predict impacts from future traffic conditions the EPD recommends that, traffic noise should be modelled using the worst case year traffic forecast within 15 years after the opening of the development. Examination of the results indicates that the Year 2018 was the worst case year and thus has been used to assess the road traffic noise impacts associated with the planned developments. Annex A presents the traffic data used in road noise assessment (am peak hour traffic forecasts) which was abstracted from the TIA Study carried out for this Project and was subsequently endorsed by the Transport Department. A copy of the letter (ref.: KR 182/192-S1) issued from Transport Department is included in the Annex H.

Traffic noise impacts were then assessed against the EIAO-TM road traffic nose limits of L_{10, peak hour} 70 dB(A) for residential uses and L_{10, peak hour} 65 dB(A) for educational institutions. Any predicted levels exceeding the EIAO-TM road traffic noise criteria are considered to constitute significant impacts and practicable direct mitigation measures will be recommended.

4.4.4 Evaluation of Impacts

The potential noise impacts on the NSRs for the Year 2018 due to operation of Link Roads G & L are discussed below and the unmitigated predicted noise levels are given in Table F-1 in Annex F.

Mei Foo Sun Chuen

As indicated in Table F-1 of Annex F, the noise levels at Mei Foo Sun Chuen Phase 3 – Block 90 and Phase 8 – Blocks 104 and 112 (i.e. NSRs MF1 to MF3) will be dominated by road traffic noise from the existing road network. The noise levels from the existing road will already exceed the road traffic noise criterion of L_{10(1 hour)}70 dB(A). Table F-1 of Annex F indicates the noise contribution from Link Roads G & L to the cumulative noise impact at Mei Foo Sun Chuen represented by NSRs MF1 to MF3 is up to 0.8 dB(A) and the noise due to the new roads will comply with the road traffic noise criterion of L_{10(1 hour)}70 dB(A). These NSRs are therefore excluded from the consideration of mitigation measures as it would not be effective to reduce the overall noise levels by 1 dB(A).

Table F-1 of Annex F indicates that the noise levels at Mei Foo Chuen Phase 8 – Blocks 112, 132 and 128 (i.e. NSRs MF4 and MF5) will comply with the road traffic noise criterion of L_10(1
hour)70 dB(A) implying traffic noise from the Link Roads G & L will not cause any adverse impacts at these NSRs. Therefore mitigation measures will not be required.

KMB Bus Depot CDA Site

Table F-1 of Annex F indicates that the noise levels at the façade of the residential buildings-Blocks 1 to 3 facing the Link Roads G & L (i.e. NSRs KMB1 to KMB3) will be dominated by road traffic noise from the existing road network. The noise levels from the existing road will already exceed the road traffic noise criterion of L_{10(1 hour)}70 dB(A). As indicated in Table F-1 of Annex F, the noise contribution from Links Roads G & L to the cumulative noise impact at KMB Bus Depot CDA site (i.e. KMB1 to KMB3) is up to 0.9 dB(A) and the noise due to the new roads will comply with the road traffic noise criterion of L_10(1
hour)70 dB(A). These NSRs are therefore excluded from the consideration of mitigation measures as it would not be effective to reduce the overall noise level by 1dB(A).

Site 10

As indicated in Table F-1 of Annex F, the noise levels at the façade of residential towers-Blocks 3 to 7 and the school facing the West Kowloon Expressway (i.e. NSRs 10S1 to 10S5 and 10S6) will be dominated by road traffic noise from the existing road network. The noise levels from the existing road will already exceed the road traffic noise criteria of L_{10(1 hour)}70 dB(A) and 65 dB(A) for residential use and schools. Table F-1 of Annex F indicates the noise contribution from Link Roads G & L to the cumulative noise impact at Site 10 (i.e. NSRs, 10S1 to 10S5 and 10S6) is up to 0.6 dB(A) and the noise due to the new roads will comply with the road traffic noise of L_{10(1 hour)}70 dB(A). Mitigation measures were not considered for these NSRs as it would not be effective to reduce the overall noise level by 1dB(A).

4.4.5 Environmental Implications

As discussed above the primary contribution of vehicle traffic noise at all of these NSRs is from existing roads. The relative contribution of traffic noise generated by vehicles using Link Roads G and L (new roads) is less than 1 dB(A). Interpretation of the assessment indicates that the requirements of the EIAO-TM are met in full. Where Link Roads G & L are excluded from the assessment of traffic noise, the major contributions to noise levels, at the NSR’s, are from vehicles using the West Kowloon Highway, Route 9 and Route 16. The ambient noise levels in the area will be elevated and is such the relative contribution from Link Roads G & L are insignificant.

Number of Dwellings Affected

Without any form of noise mitigation, it is estimated that approximately 1415 dwellings and 30 classrooms would be subject to exceedances of the road traffic noise criteria. However, all of the (1415) dwellings and (30) classrooms would be primarily affected by existing roads such as Route 9, Route 16 and West Kowloon Expressway. None of the dwellings and classrooms would therefore be affected by Link Roads G & L. As demonstrated by modelling techniques the relative contribution from Link Roads G & L to the overall noise level is less than 0.9dB(A) for the worst case situation.

4.5 Conclusion

4.5.1 Construction Phase

The cumulative impact of both unmitigated construction activities for Link Roads G & L and mitigated construction activities of part of Route 9 would cause exceedance of the daytime construction noise criterion at the nearby NSRs during the normal working hours. The most seriously affected areas is Mei Foo Sun Chuen, Phase 8, Blk 112 (at MF3) where unmitigated noise levels of up to 77dB(A) are predicted.

Therefore, adequate control measures will be necessary for the works of Link Roads G & L in order to meet the standards required. Mitigation measures including the use of quiet plant are proposed which will allow the residual noise level to be achieved. It is also recommended that regular monitoring of noise at NSRs is carried out during the construction phase.

4.5.2 Operational Phase

This assessment has predicted that the traffic noise levels including the contribution from Link Roads G & L at the year 2018 will result in exceedances of the road traffic noise criterion at the nearby NSRs such as Mei Foo Sun Chuen, KMB Bus Depot CDA site and Site 10 housing Development.

Overall noise impacts including the contribution from Link Roads G & L at some of the existing NSRs (i.e. Mei Foo Sun Chuen) will still exceed the requirements of the EIAO-TM. It must be stressed that the primary noise contribution at all of these NSRs will be from existing roads and the noise contribution on the Link Roads G and L (new roads) is less than 1 dB(A). As a result, the traffic noise impact arising from the operation of Link Roads G & L can be complied with the EIAO-TM criteria. None of these NSRs will be eligible for indirect noise mitigation as a result of the construction of the Link Roads G and L as the contribution from the new road is less than 1.0 dB(A) in every case.

Overall noise impacts including the contribution from Link Roads G & L at some planned NSRs (i.e. KMB Bus Depot CDA and Site 10 Development Site) will still exceed the EIAO-TM. However, the main noise contribution at all of these NSRs will be from existing roads with the noise contribution on Link Roads G and L (new roads) is less than 1 dB(A)). As a result, the traffic noise impact arising from the operation of Link Roads G & L can be complied with the EIAO-TM criteria.

4.2.1 Construction Noise

4.2.2 Percussive Piling

Table 4.1 Permitted Hours of Operation for Percussive Piling

4.2.3 General Construction Works

Area Sensitivity Rating

4.2.4 Operational Phase

Road Traffic Noise

4.2.6 Noise Sensitive Receivers

Existing Noise Sensitive Receivers

Planned Sensitive Uses

Table 4.5 Location of Noise Sensitive Receivers – Construction Phase

Potential Source of Impacts

Link Roads G & L

Cumulative Noise Impacts

Good Site Practice

Selecting Quieter Plant and Working Methods

Table 4.7 Sound Power Levels for Specific Silenced PME

Mitigation 1

Cumulative Noise Impacts

Table 4.9 Location of Noise Sensitive Receivers – Operational Phase

Representative

Floors

Representative

Floors