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Agreement No. DP 06/2011 Environmental Impact Assessment for Drainage Improvement Works at Ngong Ping EIA Report (Final)

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4 NOISE IMPACT ASSESSMENT

4.1 Background

4.1.1.1 Potential construction phase air-borne noise impacts may be generated as a result of the use of powered mechanical equipment (PME) for various construction activities including site formation, cut and cover works, construction of jacking and receiving pits, and formation of intakes and outfalls, as detailed in Section 2 of this report. Further details of the construction activities, programme and equipment requirements are provided in Section 4.7 below. No operational noise impacts would be anticipated for this project and have, therefore, not been considered further.

4.2 Environmental Legislation, Standards and Guidelines

4.2.1 Noise Control Ordinance and Technical Memoranda

4.2.1.1 The Noise Control Ordinance (NCO) and the EIAO provide the statutory framework for noise control. Assessment procedures and standards relevant to this project are set out in the Technical Memoranda (TM) given below.

• The TM on Environmental Impact Assessment Process (EIAO-TM);

• The TM on Noise from Construction Work other than Percussive Piling (GW-TM); and

• The TM on Noise from Construction Work in Designated Areas (DA-TM).

4.2.1.2 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 Construction Noise Permit (CNP) would be required from the Environmental Protection Department (EPD) if such works were eventually needed.

4.2.2 Noise Standards for Non-restricted Hours

4.2.2.1 Daytime construction noise (excluding percussive piling) between the hours of 0700 and 1900 on weekdays, that is, non-restricted or normal working hours, is governed by 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) for educational institutions including kindergartens (or 65dB(A) during examination periods), nurseries and all other places where unaided voice communication is required. The recommended noise standards are summarised in Table 4.1 below.



Table 4.1 Daytime Construction Noise Limits Uses Noise Standard,

Leq, 30 min dB(A) Domestic premises, hotels and hostels 75 Educational institutions, kindergartens, nurseries and all others where voice communication is required

70 (65 during examination period)

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 façade.

4.2.3 Noise Standards for Restricted Hours

4.2.3.1 During restricted works periods between 1900 and 0700 hours from Monday to Saturday and at any time on Sundays or public holidays, activities involving the use of PME for the purpose of carrying out construction work is prohibited unless a Construction Noise Permit (CNP) has been obtained.

4.2.3.2 The GW-TM provides details of the procedures adopted by the EPD for assessing such applications. The granting of a CNP is subject to the conditions as stated in the CNP, which may be revoked at any time for failure to comply with the permit conditions. A CNP may be granted in cases where the noise can be contained within the Acceptable Noise Level (ANL) at the Noise Sensitive Receivers (NSRs). ANLs are assigned depending on the Area Sensitivity Ratings (ASRs) of the study area. The ANLs for construction works in a “Designated Area” (controlled by the DA-TM) are more stringent than those given in the TM-GW.

4.2.3.3 Under the DA-TM, the use of five types of Specified Powered Mechanical Equipment (SPME), namely hand-held breaker, bulldozer, concrete lorry mixer, dump truck and hand-held vibratory poker, and undertaking three types of Prescribed Construction Works (PCW) within a designated area during restricted hours would require a valid CNP. The PCW are:

• Erecting or dismantling of formwork or scaffolding;

• Loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material; and

• Hammering.

4.2.3.4 In general, it cannot be presumed that a CNP would be granted for carrying out PCW within a designated area during restricted hours but it may be granted if the relevant ANLs and criteria stipulated in the GW-TM and DA-TM can be met.

4.2.3.5 As defined in the latest Noise Control Designated Area Plan (Plan No. EPD/AN/NT-05), the eastern part of the project area is within the Designated Area. The corresponding basic noise levels (BNLs) for evening and night-time periods are given in Table 4.2 and the figures in brackets for designated areas would apply to this area.



Table 4.2 Construction Noise Criteria for Activities other than Percussive Piling Basic Noise Levels (BNLs), dB(A) Time Period

ASR ‘A’ ASR ‘B’ ASR ‘C’ Evening (1900 to 2300 hrs)[a] 60 (45) 65 (50) 70 (55) Night-time (2300 to 0700 hrs)

45 (30) 50 (35) 55 (40)

NOTE: [a] Includes Sunday and Public Holidays during daytime and evening. Figures in brackets are BNLs for Specified Powered Mechanical Equipment (SPME) construction

work in designated areas.

4.2.3.6 As noise in restricted periods is covered by the NCO, it is not assessed further in this EIA Report under the EIAO and despite any reference made in this EIA Report to construction noise aspects during restricted periods, there is no guarantee that a CNP will be issued for the project construction. The Noise Control Authority will consider a well justified CNP application, once filed, for construction works within restricted hours as guided by the relevant TM issued under the Noise Control Ordinance. The Noise Control Authority will take into account contemporary conditions/situation of adjoining land uses and any previous complaints against construction activities at the site before making his decision in granting a CNP. Nothing in the EIA Report shall bind the Noise Control Authority in making his decision. If a CNP is to be issued, the Noise Control Authority shall include in it any condition seen fit. Failure to comply with any such conditions will lead to cancellation of the CNP and prosecution action under the NCO.

4.2.3.7 According to the construction programme detailed in Figure 2.8b, all the proposed construction works are, however, expected to be carried out during non-restricted hours. In case of any construction activities during restricted hours, it will be the Contractor’s responsibility to ensure compliance with the NCO and the relevant TMs. The Contractor will be required to submit a CNP application to the Noise Control Authority and abide by any conditions stated in the CNP, should one be issued.

4.3 Noise Sensitive Receivers

4.3.1.1 NSRs have been identified in accordance with Annex 13 of the EIAO-TM which can included domestic premises, temporary housing accommodation, educational institutions, nurseries, hospitals, medical clinics, homes for the aged, convalescent homes, places of public worship, libraries, courts of law, performing arts centres, auditoria, amphitheatres, hostels and country parks. Noise sensitive receivers present within the 300m study area boundary have been identified.

4.3.1.2 The construction sites are located to the northern side of the Po Lin Monastery, northwest of the Po Lin Monastery near Lin Ping Drive and to the north of the Ngong Ping 360 Terminal and Columbarium. The existing NSRs selected as representative for both the construction noise assessment are listed in Table 4.3 and illustrated in Figure 4.1 - 4.3. The details of the NSRs are presented in Appendix C1.


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Table 4.3 Representative Noise Sensitive Receivers NSR (1) Location Type No. of

Storeys Minimum Source-

Receiver Slant Distance (m)*

NSR1 Columbarium of Po Lin Monastery

Place of public worship

1 18.7

NSR3 Village House No. 68 Residential 2 40.8 NSR4 Village House No. 65 Residential 2 30.8 NSR5 Village House No. 49A Residential 1 6.5 NSR6(2) Village House No. 40 Residential 2 24.5 NSR7 Luen Sin Tong Place of public

worship 2 35.5

NSR8 Village House No. 34 Residential 2 26.3 NSR9 Village House Residential 2 25.7 NSR11(3) Po Lin Monastery Place of Public

Worship 1 35.9

Notes: * Slant distance is the distance from the SR to the location of the PMEs in the nearest works area.

Refer to Appendix C2 for the locations of the notional sources. (1) The numbering of the NSRs is consistent with that of the ASRs in Section 3 of this EIA Report.

SR2 and SR10 are shopping centre and kitchen of the Po Lin Monastery, respectively and, therefore, do not constitute an NSR for this assessment and as such, no NSR2 or NSR10 has been included in this assessment.

(2) NSR6 is an abandoned village house but is the closest property to the proposed construction works among the cluster of village houses in this area. It also offers shielding to 3 village houses behind it. It has, therefore, been selected to represent the NSRs in this area as a worst case as it would be the worst affected location.

(3) NSR11 is the kitchen house of Po Lin Monastery and would normally not be considered as an NSR. However, it is selected to represent the closest occupied building of the Monastery that would be the worst affected by the construction works.

4.3.1.3 The photos of the NSRs are also provided in Appendix C1.

4.4 Existing Conditions

4.4.1.1 The project site is located in a rural area and the surrounding land uses comprise village type development, government or community use such as Po Lin Monastery, with the majority of the area being green belt and Country Park. The major noise sources would be expected from commercial activities associated with the road access to the village and the Po Lin Monastery and the Ngong Ping 360 cable car.

4.4.1.2 Relevant studies of the baseline noise levels in the Ngong Ping area include the “Outlying Islands Sewerage Stage 1 Phase 1 Ngong Ping Sewage Treatment Works and Sewerage EIA” (EIA Register No. EIA-079/2002), which reported that the prevailing background noise levels in this area ranged from 48dB(A) to 62dB(A) and 45dB(A) to 54dB(A) during the daytime/evening and nighttime respectively. Traffic noise from Ngong Ping Road was determined to be a dominant background noise source, in addition to the loudspeaker announcement by the Po Lin Monastery.



4.5 Identification of Potential Noise Impacts

4.5.1.1 The potential sources of noise impact during the construction phase of the Project would be the use of PME for various construction activities. According to the construction programme in Figure 2.8b, the construction of the project would tentatively start in August 2013 and last for about 30 months. There are seven major construction activities to be carried out which are relevant to the construction noise assessment, as follows:

• Activity 1: Site formation works (All works areas with Project Area);

• Activities 2: Construction of Site Office (SO);

• Activities 3 and 4: Construction of drainage pipelines (Work Sections 1 and 3, Figure 2.9a) and box culverts (Work Sections 4 and 5, Figure 2.9a) using the cut and cover method with stockpiling activities at the stockpile areas (SA1, SO, SA2, SA3 and SA4);

• Activity 5: Construction of jacking pits (JP1 and JP2, Figure 2.9a) and receiving pits (RP1, RP2, RP3 and RP4, Figure 2.9a) and including mucking-out activities at jacking pits (JP1 and JP2) for the pipe-jacking process in Work Sections 2 and 6; and

• Activity 6: Construction of manholes, intakes and outfalls (SA1, SA2, SA3, WA3, WA4).

• Activity 7: Demolition of Site Office (SO) with associated road reinstatement and landscaping works.

4.5.1.2 For the pipe jacking, as the jacking system would be located at the bottom of the pit which is about 6m below ground level, the noise of the jacking machine would be effectively shielded from the sensitive receivers. Thus, it would not be considered as a potential noise impact during the construction phase. However, other PMEs such as air compressor, lorry and mobile crane, etc., which would be required for the pipe jacking process would be at ground level and these would be considered as potential noise sources in the noise assessment.

4.6 Concurrent Projects

4.6.1.1 There are no concurrent projects identified that would have the potential to result in cumulative noise impacts at the NSRs during the same construction period of the Project.

4.7 Assessment Approach and Assumptions

4.7.1 General Approach

4.7.1.1 In accordance with the EIAO-TM, the methodology outlined in the GW-TM has been used for the construction noise assessment. The general approach is summarised below:

• Locate the NSRs which would most likely be affected by the noise from construction works;



• Determine the items of PME for each discrete construction activity, based on the available information or agreed plant inventories;

• Assign sound power levels (SWLs) to the proposed PME according to the GW-TM or other sources;

• Calculate the distance attenuation and screening effects to NSRs from the noise source;

• Predict the construction noise levels at NSRs in the absence of any mitigation measures; and

• Include a 3dB(A) façade correction to the predicted noise levels in order to account for the façade effect at each NSR.

4.7.2 Plant Inventory

4.7.2.1 Groups of PME have been assigned to various construction activities of the project and the full plant inventory is presented in Appendix C3. The key PME to be used for the construction works activities are shown in Table 4.4 below. The Project Proponent has confirmed this plant inventory as being practical and adequate for completing the construction works within the scheduled timeframe and the is presented in Appendix B1. The plant inventory has been provided as one option which is considered technically feasible and represents a realistic worst-case scenario for assessment purposes in this EIA.

4.7.2.2 The on-time of each piece of equipment has been estimated with the reference of EIAO-GN 9/2004 to reflect the actual situation and is considered practicable and the percentages of time have been considered when calculating the cumulative Sound Power Levels (SWL) for the construction activities.

Table 4.4 PME Identified as Major Noise Sources for the Unmitigated Scenario ID PME CNP No. of

Item SWL, dB(A)

% on time

Total SWL, dB(A)

1 Activity 1 - Site Clearance Felling of Trees 1a Saw, Chain, Hand-Held CNP 202 1 114 50% 111 Removal of Trees Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70%

1b

Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 114

Activity 2 – Construction of Site Office Concrete Lorry Mixer CNP 044 1 109 50% Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70% Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100%

2

Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30%

112



ID PME CNP No. of Item

SWL, dB(A)

% on time

Total SWL, dB(A)

3 Activity 3 – Laying of Pipe by Open-cut Method 3a Excavation and installation of earth lateral support system

Excavation and installation of earth lateral support system – Excavation Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70%

3a-1


CNP 145 1 105 30% 111

Excavation and installation of earth lateral support system - Sheet Piling 3a-2 Piling, vibrating hammer CNP 172 1 115 50% 112 Excavation and installation of earth lateral support system - Delivery of Precast Elements 3a-3 Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30% 100

Excavation and installation of earth lateral support system – Generators and Pumps Water Pump (Electric) CNP 281 1 88 50%

3a-4

Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100% 100

Laying of pipe Crane, Mobile/Barge Mounted (diesel)

CNP 048 1 112 70%

Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100% Water Pump (Electric) CNP 281 1 88 50% Winch (Electric) CNP 262 1 95 50%

3b


CNP 145 1 105 30%

111

3c Backfilling the trench Backfilling the trench – Filling Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 3c-1

Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70%

114

Backfilling the trench – Compacting 3c-2 Compactor, Vibratory CNP 050 1 105 50% 102 Reinstatement of original pavement Concrete Lorry Mixer CNP 044 1 109 50% Poker, Vibratory, Hand-held CNP 170 1 113 50%

3d

Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100%

112

4 Activity 4 – Construction of Box-culvert 4a Excavation and installation of earth lateral support system

Excavation and installation of earth lateral support system – Excavation Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70%

4a-1


CNP 145 1 105 30% 111

Excavation and installation of earth lateral support system – Sheet Piling 4a-2 Piling, vibrating hammer CNP 172 1 115 50% 112 Excavation and installation of earth lateral support system - Delivery of Precast Elements 4a-3 Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30% 100

Excavation and installation of earth lateral support system – Generators and Pumps Water Pump (Electric) CNP 281 1 88 50%

4a-4





SWL, dB(A)

% on time

Total SWL, dB(A)

4b Erection of formwork, steel fixing and concreting Erection of formwork Saw, Circular, Wood CNP 201 1 108 50%

4b-1

Water Pump (Electric) CNP 281 1 88 50% 105

Steel fixing Bar Bender and Cutter (Electric) CNP 021 1 90 80%

4b-2


Concreting Concrete Lorry Mixer CNP 044 1 109 50% Crane, Mobile/Barge Mounted (diesel)

CNP 048 1 112 70%

Poker, Vibratory, Hand-held CNP 170 1 113 50%

4b-3

Water Pump (Electric) CNP 281 1 88 50%

114

4c Backfilling the trench Backfilling the trench – Filling Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 4c-1

Excavator/Loader, Wheeled/Tracked CNP 081 1 112 70%

114

Backfilling the trench – Compacting 4c-2 Compactor, Vibratory CNP 050 1 105 50% 102 Reinstatement of original pavement Concrete Lorry Mixer CNP 044 1 109 50% Poker, Vibratory, Hand-held CNP 170 1 113 50%

4d

Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100%

112

5 Activity 5 – Laying of Pipe by Pipe-jacking Method 5a Construction of jacking pits

Construction of jacking pits – Excavation Breaker, Excavator Mounted (Hydraulic)

CNP 028 1 122 70% 5a-1


CNP 145 1 105 30%

120

Construction of jacking pits - Delivery of Precast Elements 5a-2 Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30% 100

Construction of jacking pits - Generators and Pumps Water Pump (Electric) CNP 281 1 88 50% Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100%

5a-3

Air blower (electric) CNP 006 1 95 50%

101




SWL, dB(A)

% on time

Total SWL, dB(A)

Pipe jacking Crane, Mobile/Barge Mounted (diesel)

CNP 048 1 112 70%

Winch (Electric) CNP 262 1 95 50% Grout mixer CNP 105 1 90 80% Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30%

Pipe jacking machine* No Noise Impact

1 --

Grout pump CNP 106 1 --

5b

Tunnel boring machine* No Noise Impact

1 --

111

5c Construction of receiving pits Construction of receiving pits – Excavation Breaker, Excavator Mounted (Hydraulic)

CNP 028 1 122 70% 5c-1


CNP 145 1 105 30%

120

Construction of receiving pits – Delivery of Precast Elements 5c-2 Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne

CNP 145 1 105 30% 100

Construction of receiving pits – Generators and Pumps Water Pump (Electric) CNP 281 1 88 50% Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100 100%

5c-3

Air blower (electric) CNP 006 1 95 50%

101

5d Backfilling the pits Backfilling the pits – Filling Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 5d-1

Excavator/Loader, Wheeled/Tracked**

CNP 081 1 112 70%

114

Backfilling the pits – Compacting 5d-2 Compactor, Vibratory CNP 050 1 105 50% 102

6 Activity 6 – Construction of Manholes, Inlet and Outfall Structures 6a Excavation

Excavation – Rock Breaking Breaker, Excavator Mounted (Hydraulic)

CNP 028 1 122 70% 6a-1


CNP 145 1 105 30%

120

Excavation – Spoil Delivery Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 6a-2


CNP 081 1 112 70%

114

Excavation – Generators and Pumps Water Pump (Electric) CNP 281 1 88 50%

6a-3





SWL, dB(A)

% on time

Total SWL, dB(A)

6b Erection of formwork, steel fixing and concreting Erection of formwork Saw, Circular, Wood CNP 201 1 108 50%

6b-1


Steel fixing Bar Bender and Cutter (Electric) CNP 021 1 90 80%

6b-2


Concreting Concrete Lorry Mixer CNP 044 1 109 50% Crane, Mobile/Barge Mounted (diesel)

CNP 048 1 112 70%

Poker, Vibratory, Hand-held CNP 170 1 113 50%

6b-3

Water Pump (Electric) CNP 281 1 88 50%

114

6c Backfilling Backfilling – Filling Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30% 6c-1


CNP 081 1 112 70%

114

6c-2 Backfilling – Compacting Compactor, Vibratory CNP 050 1 105 50% 102

Activity 7 – Demolition of Site Office with associated road reinstatement work and landscaping works Breaker, Excavator Mounted (Hydraulic)

CNP 028 1 122 70%

Dump Truck, gross vehicle weight > 38 tonne

CNP 067 1 117 30%

7


CNP 145 1 105 30%

121

Note: * Pipe jacking system, grout pump and tunnel boring machine would be located at the bottom of the

pit which is about 6m below ground level. The noise of the machines would be effectively shielded from the sensitive receivers and thus would not be considered as a potential noise source in the construction noise assessment.

** For the construction of RP4 and Outfall B at WA4 (task ID 5 and 6), a mini excavator (CNP 082) with SWL in 94 dB(A) will be used instead of the normal excavator (CNP 081) due to lack of space near the works area and access constraints

4.7.2.3 The SWLs of the PME have been taken from Table 3 of the GW-TM. Where no SWLs are provided for individual PME in the GW-TM, reference has been made to the British Standard 5228: Part 1:2009 Noise Control on Construction and Open Sites, previous similar studies or from other EIA reports or measurements taken in other relevant studies.

4.7.2.4 The proposed plant inventory involves the use of some SPME, as detailed in Section 4.2.3.3, including dump trucks and hand-held vibratory pokers. As such, should construction works extend into restricted hours, the DA-TM will become effective and further restrictions on the acceptable noise will be imposed.



4.7.3 Construction Sequence

4.7.3.1 As detailed in Section 2.7.3 the works will be undertaken based upon two active work fronts, one for the cut and cover (C&C) works of the drainage pipeline and box culvert and another one for the trenchless drain constructions, after site clearance and the site office (SO) establishment. The details of construction sequence and the location of the Works Sections can refer to Section 2.7.3 and Figure 2.9a of the report respectively.

4.7.3.2 For the construction works of the pipeline and the box culvert by cut and cover, it is assumed that the works would be conducted section by section in the specific timeframe according to the construction programme in Figure 2.8b, with each section being approximately 40m in length and taking 2 months to construct.

4.7.4 Assessment Assumptions

4.7.4.1 With reference to Table 4.4 above, for Activity 1, during the tree felling removal activities, the excavator and dump truck would not be operating. Therefore, the sub-task Activity 1b with the highest SWL of 114dB(A) has been adopted in the unmitigated noise assessment as a worst case scenario. A similar approach has been adopted for Activity 3, Construction of Pipeline by Cut and Cover Method, with the sub-task Activity 3c with highest SWL of 114dB(A) being adopted in the noise assessment as a worst case scenario as sub-tasks 3a to 3d will not be conducted concurrently during the open cut works area. Similarly, for Activity 4 for the construction of the box culvert the highest SWL being 114dB(A). For Activity 6, the construction of Intake C and Outfall B will not be undertaken at the same time and will be constructed one after the other between Months 16 - 18. Therefore, depending upon the location of the NSR, the task closer to the NSR, that is, with the highest SWL of 120dB(A), has been adopted in the noise assessment. For example, the total SWL of the PME required for the construction of Outfall B has been adopted in the noise assessment of NSR1.

4.7.4.2 For the construction of RP4 and Outfall B involving the Construction of Receiving Pits and Outfall Structures (Tasks ID 5 and 6), a mini robot mounted excavator (CNP 082) will be used instead of the normal excavator as a result of site constraints associated with the lack of working space and access near the works area. The specific plant inventory for construction works at RP4 / Outfall B is given in Table 4.5.

Table 4.5 Specific Plant Inventory for Construction Works at RP4 / Outfall B for the Unmitigated Scenario


SWL, dB(A)

% on time

Total SWL, dB(A)

5 Activity 5 – Laying of Pipe by Pipe-jacking Method 5c+ Construction of receiving pits 5c-1 Construction of receiving pits – Excavation Breaker, Excavator Mounted

(Hydraulic) CNP 028 1 70% 122 120


CNP 145 1 30% 105




SWL, dB(A)

% on time

Total SWL, dB(A)

5c-2 Construction of receiving pits - Delivery of Precast Elements Lorry, 5.5 tonne < gross vehicle

weight <= 38 tonne CNP 145 1 30% 105 100

5c-3 Construction of receiving pits - Generators and Pumps Water Pump (Electric) CNP 281 1 50% 88 101 Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100% 100 Air blower (electric) CNP 006 1 50% 95 5d+ Backfillig the pits 5d-1 Backfillig the pits – Filling Dump Truck, gross vehicle weight >

38 tonne CNP 067 1 30% 117 112

Excavator, mini-robot mounted CNP 082 1 70% 94 5d-2 Backfillig the pits – Compacting Compactor, Vibratory CNP 050 1 50% 105 102 6 Activity 6 – Construction of Manholes, Inlet and Outfall Structures 6a+ Excavation 6a-1 Excavation - Rock Breaking Breaker, Excavator Mounted

(Hydraulic) CNP 028 1 70% 122 120


CNP 145 1 30% 105

6a-2 Excavation - Spoil Delivery Dump Truck, gross vehicle weight >

38 tonne CNP 067 1 30% 117 112

Excavator, mini-robot mounted CNP 082 1 70% 94 6a-3 Excavation - Generators and Pumps Water Pump (Electric) CNP 281 1 50% 88 100 Generator, Silenced, 75 dB(A) at 7m CNP 102 1 100% 100 6b+ Erection of formwork, steel fixing and concreting 6b-1 Erection of formwork Saw, Circular, Wood CNP 201 1 50% 108 105 Water Pump (Electric) CNP 281 1 50% 88 6b-2 Steel fixing Bar Bender and Cutter (Electric) CNP 021 1 80% 90 90 Water Pump (Electric) CNP 281 1 50% 88 6b-3 Concreting Concrete Lorry Mixer CNP 044 1 50% 109 114 Crane, Mobile/Barge Mounted

(diesel) CNP 048 1 70% 112

Poker, Vibratory, Hand-held CNP 170 1 50% 113 Water Pump (Electric) CNP 281 1 50% 88 6c+ Backfilling 6c-1 Backfilling – Filling Dump Truck, gross vehicle weight >

38 tonne CNP 067 1 30% 117 112

Excavator, mini-robot mounted CNP 082 1 70% 94 6c-2 Backfilling - Compacting Compactor, Vibratory CNP 050 1 50% 105 102



4.7.4.3 The noise levels at the ground floor of the receivers have been predicted as these are considered to represent a worst-case condition with the shortest distance between the SRs and the notional noise sources, and a 3dB(A) façade correction has been applied. Appendix C2 shows the locations of the assumed notional sources of the PMEs in the noise assessment.

4.7.4.4 As noted above, as concurrent construction activities of various works elements could occur, the works within 300m from the sensitive receiver and within line of sight of the sensitive receiver is counted as cumulative impact for the worst case scenario. Table 4.6 summarises the assumed worst case concurrent construction activities for each sensitive receiver with the distance between the SRs and the noise sources.

Table 4.6 Assumed Worst Concurrent Construction Activities for Each Sensitive Receiver

Slant Distances from NSRs (m) Notional Sources* NSR

1 NSR

3 NSR

4 NSR

5 NSR

6 NSR

7 NSR

8 NSR

9 NSR 11

Intake A (SA1) (Works Section 1) -- -- -- -- -- 226.2 -- 132.0 117.2

Intake B (SA2) (Works Section 4) -- 193.9 172.4 90.1 202.1 -- 274.2 -- --

Intake C (WA3) (Works Section 6) 183.3 -- -- -- -- -- -- -- --

Outfall A (SA3) (Works Section 5) -- 40.8 52.6 93.3 283.4 -- -- -- --

Outfall B (WA4) (Works Section 6) 18.7 -- -- -- -- -- -- -- --

JP 1 (SO) (Works Section 2) -- -- -- 288.6 -- 64.3 26.3 39.1 76.0

JP 2 (SA4) (Works Section 6) 123.1 -- -- -- -- -- -- -- --

RP 1 (WA1) (Works Section 1) -- -- -- -- -- 120.4 57.2 25.7 42.4

RP 2 (WA2) (Works Section 2) -- 299.0 248.6 176.1 24.5 -- 129.1 167.2 202.5

RP 3 (WA3) (Works Section 2) 183.3 -- -- -- -- -- -- -- --

RP 4 (WA4) (Works Section 6) 18.7 -- -- -- -- -- -- -- --

SO (SO) (Works Section 2) -- -- -- 254.4 -- 35.5 35.9 56.2 89.1

Section A1 (Works Section 1) -- -- -- -- -- 196.1 -- 99.3 84.1

Section A2 (Works Section 1) -- -- -- -- -- 164.6 99.6 63.7 50.4

Section A3 (Works Section 1) -- -- -- -- -- 127.6 65.4 30.5 35.9

Section A4 (Works Section 3) -- -- 214.1 136.7 33.0 -- 141.9 178.6 213.4



Slant Distances from NSRs (m) Notional Sources* NSR

1 NSR

3 NSR

4 NSR

5 NSR

6 NSR

7 NSR

8 NSR

9 NSR 11

Section A5 (Works Section 3) -- 233.2 187.4 104.7 79.2 -- 176.6 -- 235.1

Section A6 (Works Section 3) -- 193.5 157.7 68.0 119.6 -- 208.4 -- 261.6

Section B1 (Works Section 4) -- 193.5 163.8 74.8 166.8 -- 265.3 -- 289.6

Section B2 (Works Section 5) -- 165.7 127.1 37.5 164.6 -- 252.0 -- 299.7

Section B3 (Works Section 5) -- 134.3 92.1 6.5 175.1 -- 275.1 -- --

Section B4 (Works Section 5) -- 101.6 58.1 13.5 192.8 -- -- -- --



Note: * refer to Appendix C4 for the locations of the notional sources. Reference in bracket refers to Works

Areas as detailed in Table 2.13 or Works Sections detailed in Table 2.7. “--“ denotes the works site is more than 300m from the NSR or no there is no line of sight from the NSR.

4.7.5 Level of Uncertainty

4.7.5.1 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.

4.7.5.2 There are some limitations in the approach, such as the accuracy of predictive base data for future conditions, e.g. plant inventory for the proposed construction works. Uncertainties in the assessment of impacts have been considered when drawing conclusions from the assessment and worst case assessments made overall.

4.8 Construction Noise Assessment Results

4.8.1 Construction Noise Impact – Unmitigated Scenario

4.8.1.1 A summary of the predicted unmitigated maximum noise levels are provided in Table 4.7 below. The details of the predicted unmitigated noise levels at the representative NSRs during each construction months are presented in Appendix C4.



Table 4.7 Predicted Unmitigated Construction Noise Levels for Representative NSRs NSR Location Maximum Predicted

Construction Noise Level, dB(A)

EIAO -TM Noise Criteria, dB(A)

NSR1 Columbarium of Po Lin Monastery 91 70 NSR3 Village House No. 68 83 75 NSR4 Village House No. 65 81 75 NSR5 Village House No. 49A 93 75 NSR6 Village House No. 40 88 75 NSR7 Luen Sin Tong 85 70 NSR8 Village House No. 34 88 75 NSR9 Village House 89 75 NSR11 Po Lin Monastery 84 70 Denotes exceedance of the noise criteria

4.8.1.2 The results indicate that the noise levels at all sensitive receivers will exceed the day-time

noise criteria of 75dB(A) for the residential developments and 70dB(A) for the places of public worship during the construction activities for varying periods of time. Based upon these results, noise mitigation measures will be necessary in a number of locations to reduce the noise to acceptable levels.

4.8.2 Mitigation Measures

4.8.2.1 One of the sources of exceedances is identified to be Activity 1 – Site Clearance. This activity would be conducted along the whole alignment which will become very close to some NSRs (up to 6m). However, removal of trees would require a top down approach and according to the tree survey conducted for the area, the trees scheduled to be felled are up to a maximum of 14m tall. Thus, a noise barrier of a sufficient height to screen the high works when cutting at top sections of the trees would not be feasible.

4.8.2.2 Therefore, in order to mitigate the exceedances from the site clearance works, which is largely as a result of the use of the chain saw in close proximity to the NSRs, it is recommended that a quieter chain saw be used to mitigate the exceedances. The chain saw can be replaced with an electric chain saw with a lower noise level to reduce the noise impact to the residents during tree felling. A commonly available model, for example, the Husqvarna 316 Electric Chain Saw, has a rated maximum noise emission level of 103dB(A), which is 11dB(A) lower than the diesel powered chain saw previously assumed. Such electricity powered chain saws will effectively reduce construction noise emissions during site clearance and, thus, an electric saw with a SWL of 103dB(A) or lower is recommended for use in Activity 1. The brochure for the Husqvarna 316 Electric Chain Saw has been included in Appendix C5.

4.8.2.3 Use of other quiet equipment with lower SWL has been recommended to reduce the noise impacts for this Project. The list of assumed quieter equipment, and their respective SWLs, is presented in Table 4.8 below.



Table 4.8 Mitigated Quiet PMEs PME Reference* SWL, dB(A)

Tracked excavator fitted with hydraulic rock breaker BS D8/13# 110 Concrete lorry mixer BS D6/33 96 Tracked mobile crane (132kW, 55t) BS C3/29 98 Dump Truck BS D9/39 103 Tracked excavator (14t) BS C2/7 98 Generator, Super Silenced, 70 dB(A) at 7m CNP 103 95 Poker vibratory BS C4/34 97 Hand Held Electric Circular Saw, 150mm Blade BS D7/75 105 Electric Chain-Saw, Hand-held Ref 1+ 103 Water Pump, Submersible (Electric) CNP 283 85

Note: * reference to the British Standard BS5228-1:2009 Code of practice for noise and vibration control on

construction and open sites – Part 1: Noise. + Reference was made to Husqvarna Model 316 Electric Chain Saw, rated power being 1600W and

guaranteed maximum noise emissions being 103dB(A) as provided by manufacturer. # Sheetpile installation would be part of the earth lateral support system. An excavator with a

mounted vibrating hammer, with a noise level similar to a breaker, would be used for this installation work. Therefore, the assessment has been made with reference to an excavator mounted breaker.

4.8.2.4 Due to severe space constraints within the village, the installation of fixed temporary barriers of 2.5m high along the site boundary are not considered feasible for most of the areas as there is not sufficient space to provide the deep foundations needed to compensate for the wind loading that would occur on barriers of this height.

4.8.2.5 In respect of WA4 which is adjacent to the Columbarium (NSR1), the Columbarium itself is surrounded by two solid boundary walls of about 2.5m high and about 200mm thick which are sufficient to act as a fixed barrier. However, at intervals along the wall, vertical gaps in the wall are present which would reduce the attenuation properties of the boundary wall. As such, it is recommended that, during the construction phase at WA4, the gaps in the wall, along the front edge of the Columbarium facing the works, be covered with acoustic fabric or small barrier sections to increase the screening to NSR1 from the noise during the construction of Outfall B and RP4. A noise attenuation level of 10dB(A) for the PME, as detailed in Table 4.9 below, has been assumed for the upgraded Columbarium boundary wall. It should be noted that the access gate to the facility will not be affected. If acoustic fabric is not used, any barrier material should have a surface density of at least 10kg/m2. Figure 4.4 shows the cross section between the construction works site and public in NSR1 demonstrating how the boundary wall can shield the public within the Columbarium from works at WA4.

Table 4.9 Noise Attenuation of PMEs from the Fixed Temporary Noise Barrier for NSR1

PME Reduction Level (dB(A)) Tracked mobile crane (132kW, 55t) 10 Poker vibratory 10 Concrete lorry mixer 10 Hand Held Electric Circular Saw, 150mm Blade 10 Tracked excavator fitted with hydraulic rock breaker 10



PME Reduction Level (dB(A)) Dump Truck 10 Air blower (electric) 10 Bar Bender and Cutter (Electric) 10 Compactor, Vibratory 10 Excavator, mini-robot mounted 10 Generator, Super Silenced, 70 dB(A) at 7m 10 Lorry, 5.5 tonne < gross vehicle weight <= 38 tonne 10 Water Pump, Submersible (Electric) 10

4.8.2.6 As fixed temporary barriers along the works boundary are not feasible, with reference to

the EIA Report of Kwun Tong Line Extension (AEIAR-154/2010), the following mitigation measures have been recommended to reduce the noise impacts from specific PMEs:

• Use of mobile temporary noise barriers at individual movable and stationary PMEs. The barriers should be about 2m high which considering the low rise residential sensitive receivers would be considered sufficient for screening purposes. The barrier material shall have a surface density of at least 10kg/m2 to effectively provide noise screening. With reference to EIAO Guidance Note No.9/2004, noise reductions of 5dB(A) and 10dB(A) can be achieved by direct application of the noise barriers to movable and stationary plant, respectively; and

• Use of enclosures with covers at the 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.

4.8.2.7 Table 4.10 below summarises the mitigation measures to be adopted for PMEs being operated in all the works areas and the respective reductions in noise levels.

Table 4.10 Mitigation Measures and Assumed Effectiveness for PMEs PME Mitigation Measures Reduction Level

(dB(A)) Bar Bender and Cutter (Electric) Noise Enclosure 10 Tracked excavator fitted with hydraulic rock breaker

Temporary Noise barrier 5

Tracked excavator (14t) Temporary Noise barrier 5 Generator, Super Silenced, 70 dB(A) at 7m Noise Enclosure 10 Hand Held Electric Circular Saw, 150mm Blade

Noise Enclosure 10

4.8.3 Construction Noise Impact – Mitigated Scenario

4.8.3.1 The mitigated sound power levels for the construction equipment are presented in Appendix C6. After the implementation of the noise mitigation measures recommended above, the noise levels at NSR5 would still exceed the criteria. Residual impacts of between 4-11dB(A) are predicted. The details of the predicted noise levels at the NSRs with the implementation of the practicable mitigation measures detailed above during the



construction works are presented in Appendix C7, with a summary provided in Table 4.11 below.

Table 4.11 Predicted Mitigated Construction Noise Levels and Duration at Representative NSRs

NSR Range of Predicted

Construction Noise Level,

dB(A)

EIAO -TM Noise

Criteria, dB(A)

Period Exceeding the

Noise Standard

Remarks

NSR1 55 – 70 70 -- -- NSR3 50 – 71 75 -- -- NSR4 50 – 74 75 -- --

NSR5 48 – 86 75 Up to 1 week

Month 1: Tree removal works with SPL of 79dB(A) to the NSR which will be affected for 2 – 3 days only. Between Month 21 – 24: Construction works for the box culvert (Activity 4) at Chainage B0+45 to B2+22 , with SPL of up to 86dB(A) to the NSR in these 3-4 days.

NSR6 48 – 72 75 -- -- NSR7 50 – 70 70 -- -- NSR8 51 – 73 75 -- -- NSR9 52 – 73 75 -- -- NSR11 49 – 69 70 -- -- Denotes exceedance of the noise criteria

4.8.3.2 The NSR5 will be affected by the site clearance works in the first month. It should be

noted that site clearance works will apply to the whole alignment which is about 1km long in total and the clearance works as a whole would only last for 1 month. Thus, in reality, the affected NSRs would suffer from exceedances from site clearance for 2 – 3 days only. The exceedances at NSR 5 will be about 4 dB(A) but for this short duration only. An electric chain saw has already been assumed and no further practical mitigation measures are considered to be available,

4.8.3.3 In addition to the exceedance from the site clearance works, the exceedance at NSR5 would, also, be related to the sheet piling works during the box culvert construction (Activity 4) between Chainages B0+45 to B2+22 between Months 21 and 24 (Works Section 5). Further practicable mitigation measures, such as a fixed temporary noise barrier, have, therefore, been considered at this NSR to be implemented during this activity.

4.8.3.4 The noise exceedance would only be induced during sheet piling works which is assumed to be carried out by a hydraulic breaker. Calculations have showed that with the maximum SWL of Activity 4 being 107dB(A), NSR5 would suffer from exceedances only when



construction works are carried out within 22m either side of the NSR. Hence, the actual box-culvert works where exceedances would be anticipated would be for a total alignment length of about 44m only. Sheet piling works within this particular 44m segment would take about 3 – 4 days only to complete. The extent of the segment is shown in Figure 4.5.

4.8.3.5 Since NSR5 is a single storey village house, a fixed noise barrier of 3m in height can be installed between the NSR and the open cut trench along the 44m segment in order to further mitigate the construction noise impacts from the sheet piling work. Other PMEs, such as excavator, and vibratory poker, would also benefit from the barrier. The plant inventory assessed for Activity 4 (renumbered as Activity 4+ below) when construction works are in close proximity to NSR5 is given in Table 4.12 below and Appendix C6. An illustration of the positioning of the barrier is given in Figure 4.6.

Table 4.12 Further Mitigated Plant Inventory for Activity 4+ with Additional Noise Barrier near NSR5

ID PME Ref No of Item

% on

time

SWL, dB(A)

Mitigation Measures and Attenuation

Total SWL, dB(A)

4+ Activity 4+ – Construction of Box-culvert with additional Noise Barrier 4a Excavation and installation of earth lateral support system 4a-1 Excavation and installation of earth lateral support system - Excavation Tracked

excavator (14t) BS C2/7 1 70% 98 Fixed

Noise barrier

-5 100


CNP 145 1 30% 105

Excavation and installation of earth lateral support system - Sheet Piling 4a-2 Tracked excavator fitted with hydraulic rock breaker

BS D8/13 1 50% 110 Fixed Noise barrier

-5 102

4a-3 Excavation and installation of earth lateral support system - Delivery of Precast Elements


CNP 145 1 30% 105 100

4a-4 Excavation and installation of earth lateral support system - Generators and Pumps Water Pump,

Submersible (Electric)

CNP 283 1 50% 85 Fixed Noise

Barrier

-5 86

Generator, Super Silenced, 70 dB(A) at 7m

CNP 103 1 100%

95 Noise Enclosure

-10



ID PME Ref No of Item

% on

time

SWL, dB(A)

Mitigation Measures and Attenuation

Total SWL, dB(A)

4b Erection of formwork, steel fixing and concreting 4b-1 Erection of formwork Hand Held

Electric Circular Saw, 150mm Blade

BS D7/75 1 50% 105 Noise Enclosure

-10 92

Water Pump, Submersible (Electric)


Barrier

-5

4b-2 Steel fixing Bar Bender and

Cutter (Electric) CNP 021 1 80% 90 Noise

Enclosure -10 81



Barrier

-5

4b-3 Concreting Concrete lorry

mixer BS D6/33 1 50% 96 96

Tracked mobile crane (132kW, 55t)

BS C3/29 1 70% 98 Fixed Noise

Barrier

-5

Poker vibratory BS C4/34 1 50% 97 Fixed Noise barrier

-5



Barrier

-5

4c Backfilling the trench 4c-1 Backfilling the trench - Filling Dump Truck BS D9/39 1 30% 103 99 Tracked

excavator (14t) BS C2/7 1 70% 98 Fixed

Noise barrier

-5

4c-2 Backfilling the trench - Compacting Compactor,

Vibratory CNP 050 1 50% 105 Fixed

Noise barrier

-5 97

4d Reinstatement of original pavement Concrete lorry

mixer BS D6/33 1 50% 96 95

Poker vibratory BS C4/34 1 50% 97 Fixed Noise barrier

-5

Generator, Super Silenced, 70 dB(A) at 7m

CNP 103 1 100%

95 Noise Enclosure

-10



4.8.3.6 With the additional noise barrier, the construction noise impacts at NSR5 are further mitigated to 81dB(A) at the worst case separation distance of 6m only and exceedances would not be anticipated until construction works are carried out within 13m of NSR5, representing a segment of about 24m, as shown in Figure 4.5. The construction works within the 13m zone would be undertaken in about 3 days and, therefore, the exceedance duration is also reduced. Table 4.13 below shows the calculation of noise impact at different separation distances from NSR5 with (Activity 4+) and without (Activity 4) the proposed noise barrier.

Table 4.13 Further Mitigated Scenario for NSR5 Activity

ID Activity SWL,

dB(A) Separation Distance, m

Distance Attenuation, dB(A)

Noise Impact at NSR5

22 -32 75 13 -27 80 10 -25 82

Activity 4 107

6 -21 86 22 -32 70 13 -27 75 10 -25 77 Activity 4+ 102

6 -21 81 4.8.3.7 Notwithstanding the above measures, good site practices are, also, recommended to reduce

noise levels as far as possible. These measures include the following:

• Only well-maintained plant should be operated on-site and PME should be serviced regularly during the construction programme;

• Silencers or mufflers on construction equipment should be utilised and properly maintained throughout the construction programme;

• Any mobile PME should be sited as far from NSRs as possible;

• Machines and PME that may be in intermittent use should be shut down between work periods or should be throttled down to a minimum;

• PME known to emit noise strongly in one direction should be orientated to direct away from the nearby NSRs;

• Material stockpiles and other structures should be effectively utilised, wherever practicable, in screening noise from on-site construction activities;

• Use of acoustic enclosure, in accordance with EPD’s A Practical Guide for the Reduction of Noise from Construction Works; and

• Re-scheduling of works should be considered to ameliorate the residual impact.

4.8.3.8 Given that the recommended measures have been tried and tested and previously implemented on construction sites in Hong Kong, the level of uncertainty of the effective



implementation of the mitigation measures would be small. Notwithstanding, the EM&A programme will be implemented to ensure all mitigation measures are effective.

4.9 Cumulative Impacts

4.9.1.1 As discussed in Section 2, there are no known concurrent projects in the Study Area that may cause cumulative impacts with the Project.

4.10 Residual Impacts

4.10.1.1 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.

4.10.1.2 Although all practicable mitigation measures have been applied, NSR5 will still be subject to residual impacts of up to 6dB(A) for a maximum duration of about 1 week. NSR5 will be affected by the site clearance works for a few days, and will be further affected by Activity 4 for a duration of 3 days.

4.10.1.3 The magnitude of the residual impacts has been assessed in accordance with Section 4.4.3 of the EIAO-TM in Table 4.14 below.

Table 4.14 Assessment of Residual Impacts from Construction Noise Criteria Assessment Effects on public health and health of biota or risk to life.

The extent of noise nuisance would be unlikely to induce public health concern.

Magnitude of the adverse environmental impacts.

Residual impacts of between 4-6dB(A) could occur at 1 NSR during the construction phase based upon worse case scenarios.

Geographic extent of the adverse environmental impacts.

The geographic extent of the adverse impacts from noise will not be large and is anticipated to be limited to within about 40m from the drainage improvement project works area.

Duration and frequency of the adverse environmental impacts.

The construction noise impacts of the project will be maximum of 1 week only and are, therefore, temporary and reversible.

Likely size of the community or the environment that may be affected by the adverse impacts.

2 residents could be affected. In addition, pedestrians within immediate vicinity will be temporarily affected. The size of the community can be considered small and acceptable.

Degree to which the adverse environmental impacts are reversible or irreversible.

Construction phase impacts should be reversible.

Ecological context. Not Applicable Degree of disruption to sites of cultural heritage.

Minimal as there would be no important cultural heritage resources in the immediate vicinity of works sites



Criteria Assessment International and regional importance.

The impacts are localised and not of international and regional importance.

Likelihood and degree of uncertainty of adverse environmental impacts.

The impacts predicted are based upon worst case assumptions and as such, would not occur to the extent predicted on all occasions. However, the assessment has been made using approved mathematical modelling techniques and the degree of certainty on the results is high.

4.10.1.4 Based upon the above, the following factors should be considered in determining the

residual impacts:

• The noise impacts are not predicted to significantly affect health or cause loss of life;

• The predicted impacts are short term, temporary and reversible;

• Impacts are localised and not of international and regional importance;

• The geographic extent of the adverse impacts is confined to small areas around the works sites at two specific locations only and would not unduly affect the welfare of the local community or adjacent agricultural activities;

• The mitigation measures proposed will reduce the overall levels of impacts; and

• The study area has not shown itself to be fragile or undisturbed.

4.10.1.5 As such, given the benefits of the project to the local community and the very short term nature of the residual impacts predicted, the residual impacts associated with the construction phase exceedances for the drainage improvement works would be considered minor and acceptable.

4.11 Environmental Monitoring and Audit

4.11.1.1 The assessment has concluded that, despite the implementation of the maximum practicable extent of mitigation measures, adverse residual impacts during the construction phase will occur as a result of the implementation of the project. As such, it is recommended that construction phase environmental monitoring and audit (EM&A) is undertaken to ensure that impacts do not occur beyond unavoidable levels. It is noted that during the construction process, episodes of noise higher levels may occur and it will be the function of the EM&A process to identify these events and take the necessary action such as, for example, temporarily adjustment of the number of plant to be used or an equivalent measure as necessary.

4.11.1.2 Further details of the specific EM&A requirements are detailed in Section 10 of this report and in the EM&A Manual under separate cover. The procedure for complaints will include the provision of a hotline number for the public to use when required.



4.12 Summary and Conclusions

4.12.1.1 The results of the construction noise assessment indicate that the noise levels at 1 NSR, after the implementation of all practical direct mitigation measures, would still exceed the stipulated noise criteria in some locations for a short duration of 1 week only. However, the residual impacts have been assessed and concluded to be temporary, reversible and unlikely to induce public health concerns to the community and as such, are considered to be minor and acceptable.

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