TABLE OF CONTENTS

4 Noise Impact. 4-1

4.1 Introduction. 4-1

4.2 Environmental Legislations, Standards and Guidelines. 4-1

4.3 Description of Environment 4-3

4.4 Identification of Noise Sensitive Receivers. 4-3

4.5 Identification of Environmental Impacts. 4-2

4.6 Assessment Methodology. 4-3

4.7 Prediction and Evaluation of Environmental Impacts. 4-5

4.8 Mitigation of Adverse Environmental Impacts. 4-7

4.9 Evaluation of Residual Impacts. 4-13

4.10 Environmental Monitoring and Audit 4-13

4.11 Conclusion. 4-14

LIST OF TABLES

Table 4.1 Daytime Construction Noise Criteria

Table 4.2 Area Sensitivity Ratings

Table 4.3 Acceptable Noise Level for Fixed Noise Sources

Table 4.4 Noise Sensitive Receivers and Representative Noise Assessment Points

Table 4.5 Identified Representative Noise Assessment Points for Construction Noise Impact Assessment

Table 4.6 Identified Representative Noise Assessment Points for Fixed Noise Sources Impact Assessment

Table 4.7 Summary of Unmitigated Construction Noise Levels

Table 4.8 Summary of Predicted Fixed Plant Noise Levels from the Proposed Underground Pumps without Mitigation Measures

Table 4.9 SWL of Quiet PME Adopted for Construction Noise Mitigation

Table 4.10 Summary of Mitigated Construction Noise Levels

Table 4.11 Summary of Cumulative Construction Noise Levels with Concurrent Projects

LIST OF FIGURES

Figure 4.1 Locations of Noise Sensitive Receivers and Representative Noise Assessment Points

LIST OF APPENDICES

Appendix 4.1 Determination of Fixed Plant Noise Criteria

Appendix 4.2 Locations of Works Area and Noise Assessment Points

Appendix 4.3 Construction Plant Inventory (Unmitigated Scenario)

Appendix 4.4 Unmitigated Construction Noise Calculation

Appendix 4.5 Operational Phase Fixed Plant Noise Calculation (Unmitigated Scenario)

Appendix 4.6 Construction Plant Inventory (Mitigated Scenario)

Appendix 4.7 Mitigated Construction Noise Calculation

Appendix 4.8 Further Mitigated Construction Noise Calculation for NAP11 and NAP16

Appendix 4.9 Cumulative Construction Noise Calculation

4 Noise Impact

4.1 Introduction

4.1.1.1 This section presents the assessment on potential noise impacts arising from construction and operation of the Project, which has been conducted in accordance with the criteria and guidelines as stated in Annexes 5 and 13 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) as well as the requirements given in Clause 3.4.5 and Appendix C of the EIA Study Brief (No. ESB-320/2019).

4.2 Environmental Legislations, Standards and Guidelines

4.2.1.1 Noise impacts were assessed in accordance with the criteria and methodology given in the Technical Memoranda (TMs) issued under the Noise Control Ordinance (Cap. 400) (NCO) and Annexes 5 and 13 in the EIAO-TM.

4.2.1.2 The NCO, and Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) provide the statutory framework for noise control. Assessment procedures and standards are set out in the following TMs:

· EIAO-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)

· Technical Memorandum for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Sites (IND-TM)

4.2.1.3 The NCO provides the statutory framework for noise control of construction work, other than percussive piling, using powered mechanical equipment (PME) between the hours of 1900 and 0700 hours or at any time on Sundays and general holiday (i.e. restricted hours). Noise control on construction activities taking place at other times is subject to the “Noise Standards for Daytime Construction Activities” in Table 1B of Annex 5 in the EIAO-TM. The criteria are summarised in Table 4.1.

Table 4.1 Daytime Construction Noise Criteria

Uses	Daytime Noise Criteria, Leq, 30min, dB(A)
Domestic premises, hotel, hostel	75
Educational Institution	70
Educational Institution (during examination)	65

Note: The above standards apply to uses which rely on opened windows for ventilation.

4.2.1.4 Based on the currently envisaged construction programme, no work will be required in restricted hours as defined under the NCO. In case of any construction activities during restricted hours, it is the contractor’s responsibility to ensure compliance with the Construction Noise Permit (CNP) and the relevant TMs under the NCO. The contractor will be required to submit CNP application to the Noise Control Authority and abide by any conditions stated in the CNP, should one be issued. Regardless of the results of construction noise impact assessment in this EIA study, the Noise Control Authority will process Construction Noise Permit (CNP) application, if necessary, based on the NCO, the relevant technical memoranda issued under the NCO, and the contemporary conditions/ situations.

4.2.1.5 For the noise from fixed sources or industrial activities, the IND-TM issued under NCO has stipulated appropriate Acceptable Noise Levels (ANLs) on the basis of an Area Sensitivity Rating that is based on the characteristics of the area within which the NSRs are located, such as rural, village, low-density residential, or urban. The presence of "Influencing Factors" (IFs), which include the Hong Kong International Airport, industrial area or major roads with an annual average daily traffic flow in excess of 30,000, can further affect the Area Sensitivity Ratings and hence the ANL as shown in Table 4.2.

Table 4.2 Area Sensitivity Ratings

Type of Area Containing NSR	Degree to which NSR is Affected by Influencing Factors
	Not Affected	Indirectly Affected	Directly Affected
(i) Rural area, including country parks or village type developments	A	B	B
(ii) Low density residential area consisting of low-rise or isolated high-rise developments	A	B	C
(iii) Urban area	B	C	C
(iv) Area other than those above	B	B	C

4.2.1.6 According to the IND-TM, the ANLs for different Area Sensitivity Ratings during different periods are given in Table 4.3 below.

Table 4.3 Acceptable Noise Level for Fixed Noise Sources

Time Period	Acceptable Noise Level (ANL) for Different Area Sensitivity Rating (Leq 30min, dB(A))
	ASR A	ASR B	ASR C
Day (0700 to 1900 hrs)	60	65	70
Evening (1900 to 2300 hrs)	60	65	70
Night (2300 to 0700 hrs)	50	55	60

4.2.1.7 The Project site is not located in rural area, low density residential area or urban area. The NSRs are considered located at (ii) low density residential area and (iv) area other than those above according to Table 4.2. The corresponding ANLs for noise sensitive façade are listed in Table 4.3.

4.2.1.8 The assessment area for the fixed plant noise impact assessment is defined by a distance of 300 m from the boundary of the proposed fixed noise source, i.e. the underground waterpump and UV disinfection system located beneath Shing Mun Tunnel Road by the bankside of mid-stream TWN. Areas to the southeast of the proposed fixed noise sources were occupied by industrial buildings / areas zoned as “Industrial” (“I”) under the Approved Sha Tin Outline Zoning Plan (OZP) No. S/ST/36. The IND-TM has laid down the procedures for determining ASRs for NSRs in proximity to “industrial” zone i.e. Any NSR shall, irrespective of Table 1 of IND-TM, be assigned an ASR of “C” if it is within 100m of a zone designated as “Industrial” or “Industrial Estate” on a statutory Outline Zoning Plan, or an ASR of “B” if it is between 100m and 250m from such a zone, except in cases where Table 1 of IND-TM indicates an ASR of “C”. Hence, Area Sensitivity Rating is assigned as "C" to Lin Fung House (NAP14) and Shing Ho Building (NAP15); and “B” to 1 Tung Lo Wan Village (NAP13), since they are located within 100m and between 100m and 250m from “Industrial” zone respectively according to the Approved Sha Tin OZP No. S/ST/36. For the other representative noise assessment points for fixed noise sources impact assessment, they have direct line of sight to Shing Mun Tunnel Road / Tai Po Road (Shatin Section) and would be directly affected by these roads. Based on the Annual Traffic Census published by TD, the annual average daily traffic (AADT) of those roads are more than 30,000 and is considered as an Influencing Factor (IF) according to the TM. An Area Sensitivity Rating of “C” is hence assigned to Mei Wai House (NAP8), Mei Yeung House, Mei Lam Estate (NAP9a & NAP9b), TWGHS Tsoi Wing Sing Primary School (NAP11) and Buddhist Wong Wan Tin College (NAP12) which are located in area other than rural area, low density residential area or urban area, as well as to the Peak House (NAP10) which belongs to low density residential area consisting of low-rise developments.

4.2.1.9 As stipulated in Annex 5 of the EIAO-TM, the noise standard for planning purposes for fixed noise source are (a) 5 dB(A) below the appropriate ANL shown in Table 3 of the IND-TM, or (b) the prevailing background noise levels (for quiet areas with level 5 dB(A) below the ANL). In this regard, noise surveys in the vicinity of the representative NSRs were conducted in October 2021 and November 2021 to determine the background noise levels. The survey results were compared with the ANL-5 dB(A) criteria to determine the noise criteria to be adopted in this EIA Report. Locations of noise measurement points and measured background noise levels, as well as the assessment criteria for the proposed fixed noise sources of the Project, as adopted in this EIA Report, are presented in Appendix 4.1.

4.2.1.10 In any event, the Area Sensitivity Ratings assumed in this EIA Report are for indicative assessment only. It should be noted that fixed noise sources are controlled under Section 13 of the NCO. At the time of investigation, the Noise Control Authority shall determine noise impact from concerned fixed noise sources on the basis of prevailing legislation and practices being in force, and taking account of contemporary conditions / situation of adjoining land uses. Nothing in this EIA Report shall bind the Noise Control Authority in the context of law enforcement against all the fixed noise sources being assessed.

4.3 Description of Environment

4.3.1.1 The Project site located at the existing Tai Wai Nullah. The Project site is surrounded mainly by residential developments. . Referring to the findings of the site visit, the existing dominant noise source in the assessment area is traffic noise from along Shing Mun Tunnel Road, Tai Po Road (Tai Wai), Tsing Sha Highway, Mei Tin Road, Heung Fan Liu Street and Pik Tin Street. Industrial fixed plant noise in the assessment area is insignificant.

4.4 Identification of Noise Sensitive Receivers

4.4.1.1 In accordance with Clause 3.4.5.2 of the EIA Study Brief (No. ESB-320/2019), the construction noise assessment area is defined by a distance of 300 m from the boundary of the Project whilst the fixed noise source assessment area is defined by a distance of 300 m from the boundary of the proposed fixed plant as illustrated in Figure 4.1.

4.4.1.2 Based on the finding of the site visit and review of latest information including topographic maps, OZPs (such as the Approved Sha Tin OZP No. S/ST/36) and other published plans in the vicinity of the Project site, all existing noise sensitive receivers (NSRs) within 300m area from Project boundary have been identified as summarised in Table 4.4 and are shown in Figure 4.1. Selected NSRs were identified as representative Noise Assessment Points (NAP) quantitative noise impact assessment as detailed in Section 4.4.1.3 and Section 4.4.1.4 and their photographs are provided in Appendix 4.2.

Table 4.4 Noise Sensitive Receivers and Representative Noise Assessment Points

NSR ID	Description	Land Use	No. of Storeys	NAP ID	NAP Description	Quantitative Noise Impact Assessment ^[1]
						Construction	Operation
N1	Heung Fan Liu New Village	Residential	3	NAP1	Temporary Accommodations	Yes	No
N2	Mei Tin Estate	Residential	40	NAP2a	Mei King House, Mei Tin Estate	Yes	No
				NAP2b	Mei Chuen House, Mei Tin Estate	Yes	No
N3	Mei Ying Court	Residential	27	NAP3	Mei Ying Court	Yes	No
N4	Pui Kiu College	Educational Institution	7	-	-	No	No
N5	Tai Wai New Village	Residential	3	-	-	No	No
N6	Granville Garden	Residential	28	NAP4	Tower 1, Granville Garden	Yes	No
N7	Park View Garden	Residential	27	NAP5	Block 2, Park View Garden	Yes	No
N8	Mei Pak Court	Residential	32	NAP6	Mei Pak Court	Yes	No
N9	Mei Chung Court	Residential	27-35	-	-	No	No
N10	Free Methodist Mei Lam Primary School	Educational institution	7	-	-	No	No
N11	Lock Tao Secondary School	Educational institution	6	-	-	No	No
N12	St. Margaret's Girls' College	Educational institution	6	-	-	No	No
N13	May Shing Court	Residential	34	NAP7	Kwai Shing House, May Shing Court	Yes	No
N14	Mei Wai House	Residential	35	NAP8	Mei Wai House	Yes	Yes
N15	Mei Lam Estate	Residential	18-28	NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Yes	Yes
				NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Yes	Yes
N16	TWGHs Tsoi Wing Sing Primary School	Educational institution	7	NAP11	TWGHs Tsoi Wing Sing Primary School	Yes	Yes
N17	Buddhist Wong Wan Tin College	Educational institution	6	NAP12	Buddhist Wong Wan Tin College	Yes	Yes
N18	Peak One	Residential	6-15	-	-	No	No
N19	Peak House	Residential	3	NAP10	Peak House	Yes	Yes
N20	Tung Lo Wan Village Extension	Residential	3	-	-	No	No
N21	The Salvation Army Bradbury Home of Loving Kindness	Home for the aged	3	-	-	No	No
N22	The Great Hill	Residential	2-13	-	-	No	No
N23	ELCHK Living Spirit Lutheran Church	Place of Public Worship	3	-	-	No	No
N24	Lutheran Kindergarten	Educational institution	2	-	-	No	No
N25	Tung Lo Wan Village	Residential	2-4	NAP13	Tung Lo Wan Village	Yes	Yes
N26	On Ting Terrace	Residential	3	-	-	No	No
N27	Shatin Public School	Educational institution	2	-	-	No	No
N28	The Garrison	Residential	18	-	-	No	No
N29	Glamour Garden	Residential	24	-	-	No	No
N30	Grandeur Garden	Residential	16	-	-	No	No
N31	Residential along Chik Fai Street	Residential	5	-	-	No	No
N32	Residential along Tai Wai Road	Residential	10	-	-	No	No
N33	Residential along Chik Shun Street	Residential	2-5	-	-	No	No
N34	Kwai Wai Building at Chik Chuen Street	Residential	5	-	-	No	No
N35	Residential along Chik Chuen Street	Residential	3-5	NAP14	Lin Fung House	Yes	Yes
N36	Residential along Chik Fu Street	Residential	3-5	-	-	No	No
N37	Village Houses at Tai Wai	Residential	2-3	-	-	No	No
N38	Residential along Shing Ho Road	Residential	3	-	-	No	No
N39	Shing Ho Building	Residential	3	NAP15	Shing Ho Building	Yes	Yes
N40	TWGHs Sin Chu Wan Primary School	Educational institution	7	NAP16	TWGHs Sin Chu Wan Primary School	Yes	No
N41	Residential along Chik Fuk Street	Residential	4-5	-	-	No	No
N42	Sun Chui Estate	Residential	18-28	-	-	No	No
N43	San Tin Wai	Residential	3	-	-	No	No
N44	Che Kung Temple	Place of Public Worship	2	-	-	No	No
N45	Richmond Villa	Residential	3	-	-	No	No
N46	Lei Uk Tsuen	Residential	2-3	-	-	No	No
N47	Man Lai Court	Residential	20	NAP17	Man Lai Court	Yes	No
N48	Caritas Lok Jun School	Educational Institution	5	-	-	No	No
N49	Immaculate Heart of Mary School	Educational Institution	5	-	-	No	No
N50	Caritas Lok Jun School Hostel	Residential	3	-	-	No	No
N51	Caritas Institute of Community Education	Educational Institution	7	-	-	No	No
N52	St. Alfred’s Church	Place of Public Worship	3	-	-	No	No
N53	Sha Tin Government Secondary School	Educational Institution	5	-	-	No	No
Planned Noise Sensitive Receivers
NP1	Planned Comprehensive Development Area Next to Tai Wai Station	Residential	44	NAP18	Planned Comprehensive Development Area Next to Tai Wai Station	Yes	No

Note:

[1] The first layer of NSRs would provide acoustic shielding to those receivers at further distance behind. The predicted noise levels at the first layer of NSRs which rely on opened windows for ventilation represent the worst-case scenario, and therefore representative Noise Assessment Points (NAPs) at these NSRs were selected for quantitative noise impact assessment as detailed in Section 4.4.1.3 and Section 4.4.1.4.

Construction Noise Impact

4.4.1.3 The construction noise criteria set in Annex 5 in the EIAO-TM only apply on uses which rely on opened windows for ventilation. The first layer of NSRs would provide acoustic shielding to those receivers at further distance behind. The predicted noise levels at the first layer of NSRs which rely on opened windows for ventilation represent the worst-case scenario, and therefore representative Noise Assessment Points (NAPs) at these NSRs were selected for construction noise impact assessment. The identified representative NAPs are summarised in Table 4.5 and their locations are shown in Figure 4.1.

Table 4.5 Identified Representative Noise Assessment Points for Construction Noise Impact Assessment

NAP ID	Description	Land Use	No. of Storeys	Location of Selected Assessment Point	Approximate Horizontal Distance from the Nearest Site Boundary (m)	Daytime Noise Criterion (Leq, 30 mins, dB(A))^[1]
NAP1	Temporary Accommodations	Residential	2	G/F	5	75
NAP2a	Mei King House, Mei Tin Estate	Residential	40	G/F	21	75
NAP2b	Mei Chuen House, Mei Tin Estate	Residential	40	G/F	21	75
NAP3	Mei Ying Court	Residential	27	G/F	20	75
NAP4	Tower 1, Granville Garden	Residential	28	G/F	15	75
NAP5	Block 2, Park View Garden	Residential	27	G/F	27	75
NAP6	Mei Pak Court	Residential	32	G/F	24	75
NAP7	Kwai Shing House, May Shing Court	Residential	35	G/F	11	75
NAP8	Mei Wai House	Residential	35	G/F	18	75
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Residential	20	G/F	17	75
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Residential	20	G/F	29	75
NAP10	Peak House	Residential	3	G/F	58	75
NAP11	TWGHs Tsoi Wing Sing Primary School	Educational Institution	7	G/F	13	70/65
NAP12	Buddhist Wong Wan Tin College	Educational Institution	6	G/F	27	70/65
NAP13	Tung Lo Wan Village	Residential	3	G/F	96	75
NAP14	Lin Fung House	Residential	3	G/F	14	75
NAP15	Shing Ho Building	Residential	5	G/F	15	75
NAP16	TWGHs Sin Chu Wan Primary School	Educational Institution	7	G/F	21	70/65
NAP17	Man Lai Court	Residential	20	G/F	5	75
NAP18	Planned Comprehensive Development Area Next to Tai Wai Station	Residential	-	G/F	44	75

Note:

[1] EIAO-TM noise criteria adopted: 75 dB(A) for residential dwelling; 70 dB(A) during normal school days / 65 dB(A) during examination period for educational institution.

Operation Noise Impact

4.4.1.4 The first layer of NSRs would provide acoustic shielding to those receivers at further distance behind. The predicted noise levels at the first layer of NSRs which rely on opened windows for ventilation represent the worst-case scenario, and therefore representative NAPs at these NSRs were selected for fixed noise sources impact assessment. The identified representative NAPs are summarised in Table 4.6 and their locations are shown in Figure 4.1.

Table 4.6 Identified Representative Noise Assessment Points for Fixed Noise Sources Impact Assessment

NAP ID	Description	Land Use	No. of Storeys	Location of Selected Assessment Point	Approximate Horizontal Distance from Nearest Boundary (m)		Daytime & Evening Noise Criteria, dB(A)^[1]
					UV Disinfection System	Underground Water Pumps
NAP8	Mei Wai House	Residential	35	G/F	202	277	55
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Residential	20	G/F	136	200	55
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Residential	20	G/F	117	176	55
NAP10	Peak House	Residential	3	G/F	116	116	50
NAP11	TWGHs Tsoi Wing Sing Primary School	Educational Institution	7	G/F	58	114	55
NAP12	Buddhist Wong Wan Tin College	Educational Institution	6	G/F	70	87	55
NAP13	Tung Lo Wan Village	Residential	3	G/F	209	139	50
NAP14	Lin Fung House	Residential	3	G/F	197	138	55
NAP15	Shing Ho Building	Residential	3	G/F	263	201	55

Note:

[1] The proposed UV disinfection system and underground water pumps would not operate during night-time (2300 – 0700 hours). Daytime / Evening criterion is therefore adopted.

4.5 Identification of Environmental Impacts

4.5.1 Construction Phase

4.5.1.1 The main construction tasks of the Project include:

(A) Channel bed modification for Sections 1 to 6;

(B) Improvement of existing walkways such as construction of viewing deck/pavilion, renovation of existing footbridges for Section 1 to 5 and demolition of existing footbridge in Sections 3 and 5, as well as improvement of riparian public open spaces (including construction of riparian walkway, water play features and UV Disinfection System, and visitor facilities) in Sections 2 to 4;

(C) Construction of dry weather flow interceptor (DWFI) system along the nullah and associated connection works to existing sewerage system for Sections 1 (from north of Tsuen Nam Road near Tai Wai Soccer Pitch) to 5 & underground pumping facilities (including underground water pumps, water pipes, wet well and valve chamber) in Section 3 and underground water pipes (mainly housed within the DWFI system and to be constructed alongside construction of DWFI system) for Sections 3 to 6 for ecological enhancement associated water retention and supplement

(D) Landscape works along nullah bank and utility works for Sections 1 to 5

(E) Desilting at downstream tidal zone for Section 1

4.5.1.2 The tentative construction programme, locations of the works of the Project as defined in the EIA and plant inventory provided by the Project Engineer for the construction noise impact assessment are presented in Appendix 2.2, Appendix 4.2 and Appendix 4.3 respectively. The feasibility and practicability of the plants adopted and their details for the assessment have been confirmed by the Project Engineer. Referring to construction programme, the Project site would be divided into six work sections, Section 1 to Section 6. The construction works will be carried out section by section, from the downstream to upstream of each work section. Based on the preliminary engineering design, the maximum size of the active construction works area at any one time would not be longer than 100m along the nullah at each work section. The construction tasks (A) to (D) would be undertaken on almost all work sections and completed before commencement of the similar construction tasks at another work section. The desilting works at downstream tidal zone (Task E) would be carried out at Work Section 1 only. Therefore, the area of active work site is limited.

4.5.1.3 Potential source of noise impact arising from the construction of the Project would be the use of PME for various construction activities. No marine transportation of construction materials and waste is required. Based on the currently envisaged construction programme, works using PME during restricted hours (i.e. the hours from 1900 to 0700 hours or at any time on a general holiday) or percussive piling works would not be required. Excavation and lateral support (ELS) which would involve sheet-piling works would be required (Appendix 4.3 refers). The PME required for sheet-piling has been included in the plant inventory for the construction noise impact assessment. Only impacts from daytime general construction activities have been assessed in this EIA Report. As only limited sheet-piling works would be involved in construction phase of the Project, potential ground-borne construction noise impact would not be anticipated.

4.5.1.4 Referring to Table 2.2, the planned box culverts proposed in Chui Tin Street under “Drainage Improvement Works in Sha Tin and Sai Kung”, “Revised Trunk Road T4 in Sha Tin” and “Joint-user complex at Tsuen Nam Road, Tai Wai” would be located within 300m assessment area of this Project. Representative NSRs located within 300m assessment area of these concurrent projects include NAP8 to NAP18 for “Revised Trunk Road T4 in Sha Tin”; NAP14 to NAP18 for “Joint-user complex at Tsuen Nam Road, Tai Wai”; and NAP17 and NAP18 for the planned box culverts proposed in Chui Tin Street under “Drainage Improvement Works in Sha Tin and Sai Kung”. Potential cumulative construction noise may be anticipated at these NSRs.

4.5.2 Operational Phase

4.5.2.1 During operational phase, fixed plant noise from the operation of the proposed underground waterpump and UV disinfection system located beneath Shing Mun Tunnel Road by the bankside of mid-stream TWN would be the major source of noise impacts based on the current design as described in Section 2.3.

4.6 Assessment Methodology

4.6.1 Construction Phase

4.6.1.1 The methodology for the construction noise impact assessment follows the procedures outlined in the GW-TM. The general approach is summarised below:

· Identify representative NSRs which would most likely be affected by the noise from the construction work;

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

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

· Calculate distance attenuation and screening effects to NSRs from notional noise source;

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

· Consider cumulative impact from concurrent projects within 300 m of the NSRs, if any; and

· Compare the cumulative construction noise level against the corresponding noise criterion and propose suitable mitigation measures where necessary.

4.6.1.2 The assessment of construction noise was undertaken based on standard acoustic principles. SWLs of equipment were taken from Table 3 of the GW-TM and “Sound power levels of other commonly used PME” issued by EPD. Where no relevant SWL can be found in the GW-TM and other PME, reference is made to the information relating to Quality Powered Mechanical Equipment (QPME) available at EPD’s website or PME specification published by equipment manufacturer. Groups of PME were assigned for various construction activities of the proposed Project. The Project Proponent has confirmed that the proposed plant inventories as being practical and adequate for completing the works within the scheduled timeframe.

4.6.1.3 The assessment was undertaken based on the assumption that all items of construction equipment would be located at a notional noise source point or probable source position where specific activity is to be performed. Referring to the preliminary engineering design, under each main construction task, only one sub-plant / sub-group in a construction task will be operating at the same time. The sound pressure level (SPL) of each construction task has been calculated, depending on the number of plant items involved, utilisation rate and the distance from the NSR. A positive 3 dB(A) façade correction has been added to the predicted noise levels to account for the façade effect at each assessment point. The noise levels at the NSRs have then been predicted by adding up the SPLs of all concurrent construction tasks from the Project and other concurrent projects identified during the EIA study within the 300m assessment area.

4.6.1.4 The unmitigated construction noise impacts at the identified NSRs have been predicted accordingly. Practicable direct noise mitigation measures including the use of quieter equipment, movable noise barriers and quieter alternative methods have been considered if exceedance of relevant noise standards is predicted. Appropriate correction factors for barrier effect have been adopted in accordance with Section 2.10 of the GW-TM. In cases where the mitigated noise levels still exceed the relevant criteria, the duration of noise exceedance would be estimated.

4.6.2 Operational Phase

4.6.2.1 During operational phase, fixed plant noise impact would arise from the operation of the underground waterpump and UV disinfection system located beneath Shing Mun Tunnel Road by the bankside of mid-stream TWN. The fixed plant noise impact was assessed in accordance with the IND-TM. The distance attenuation was estimated using the standard acoustic equation and a positive 3 dB(A) façade correction was added to the predicted noise levels to account for the façade effect at each noise assessment point.

4.6.2.2 Based on the current design information, the proposed underground water pumps (one on-duty and one standby) would be housed in an underground valve chamber and wet well. The on-duty equipment would not operate during night-time (i.e. 2300 – 0700 hours). The second pump will be served as a stand-by pump in case of pump fail / maintenance. The SWL of the fixed plants were referenced to engineering design information and manufacture’s catalogue of plants of equivalent / similar specifications. The fixed plant / equipment inventory of the design at the time of preparation of this EIA is presented in Appendix 4.5. The equipment inventory has been confirmed with the Project Engineer. The noise performance of the proposed fixed plants would be reviewed during detailed design stage with due regard to the characteristics of tonality, impulsiveness and intermittency. If the noise exhibits characteristics of tonality, intermittency or impulsiveness during the detailed design or the commissioning of the plant, the SWL should be reduced in accordance with the recommendation given in Section 3.3 of IND-TM to ensure noise compliance at the NSRs. As the submersible pumps would be housed inside underground valve chamber and wet well below the nullah bed, a noise reduction of 20 dB(A) was applied to the noise levels generated by the equipment.

4.6.2.3 For the proposed UV disinfection system, since detailed design information and noise specification have yet to be confirmed, the maximum permissible noise emission levels (Max SWL), taking into account cumulative noise levels from the proposed underground water pumps, were determined for future detailed design of the fixed plant to ensure compliance with the relevant noise criteria. It is assumed that all the fixed plant within the same location would be operated simultaneously for the worst-case scenario. A positive 3 dB(A) is added to the predicted noise levels at the NSRs due to the façade effect. The following standard acoustic formula was used for calculating the Max SWL of the fixed plant.

SPL = Max SWL – DC + FC – BC + TC

Where:

SPL Sound Pressure Level, in dB(A)

Max SWL Maximum Permissible SWL, in dB(A)

DC Distance Attenuation, in dB(A) (i.e. 20logD + 8 [where D is the distance in metres])

FC Façade Correction, in dB(A) (i.e. 3 dB(A))

BC Barrier Correction, in dB(A)

TC Tonal correction, in dB(A)

4.6.2.4 If the noise exhibits characteristics of tonality, intermittency or impulsiveness during the detailed design or the commissioning of the plant, the SWL should be reduced in accordance with the recommendation given in Section 3.3 of IND-TM to ensure noise compliance at the NSRs.

4.7 Prediction and Evaluation of Environmental Impacts

4.7.1 Construction Phase

4.7.1.1 Under unmitigated scenario, exceedances of the construction noise criteria for residential uses and educational institution during daytime would be predicted. Details of the unmitigated construction noise assessment are presented in Appendix 4.4 with the results summarised in Table 4.7.

Table 4.7 Summary of Unmitigated Construction Noise Levels

NAP ID	Description	Land Use	Daytime Noise Criterion, Leq, 30 mins dB(A)^[1]	Predicted Unmitigated Maximum Construction Noise Levels, Leq, 30 mins dB(A)^[2]	Max. Noise Exceedance, dB(A)^[3]
NAP1	Temporary Accommodations	Residential	75	84	9
NAP2a	Mei King House, Mei Tin Estate	Residential	75	87	12
NAP2b	Mei Chuen House, Mei Tin Estate	Residential	75	87	12
NAP3	Mei Ying Court	Residential	75	86	11
NAP4	Tower 1, Granville Garden	Residential	75	88	13
NAP5	Block 2, Park View Garden	Residential	75	85	10
NAP6	Mei Pak Court	Residential	75	84	9
NAP7	Kwai Shing House, May Shing Court	Residential	75	83	8
NAP8	Mei Wai House	Residential	75	86	11
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Residential	75	90	15
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Residential	75	84	9
NAP10	Peak House	Residential	75	74	0
NAP11	TWGHs Tsoi Wing Sing Primary School	Educational Institution	70/65	82	12 / 17
NAP12	Buddhist Wong Wan Tin College	Educational Institution	70/65	81	11 / 16
NAP13	Tung Lo Wan Village	Residential	75	71	0
NAP14	Lin Fung House	Residential	75	82	7
NAP15	Shing Ho Building	Residential	75	82	7
NAP16	TWGHs Sin Chu Wan Primary School	Educational Institution	70/65	83	13 / 18
NAP17	Man Lai Court	Residential	75	85	10
NAP18	Planned Comprehensive Development Area Next to Tai Wai Station	Residential	75	76	1

Note:

[1] EIAO-TM noise criteria adopted: 75 dB(A) for residential dwelling; 70 dB(A) during normal school days / 65 dB(A) during examination period for educational institution.

[2] Bolded values indicate exceedance of EIAO-TM noise criteria of 75 dB(A) for residential dwellings, or 70 dB(A) for educational institution during normal school days; while underlined value indicates exceedance of EIAO-TM noise criteria of 65 dB(A) for educational institution during examination period. 

[3] For educational institution, "maximum noise exceedance for general school day / maximum noise exceedance during examination period".

4.7.1.2 The unmitigated maximum construction noise levels at the identified representative NSRs would range from 71 – 90 dB(A). Except for NAP10 and NAP13, all NAPs would exceed the relevant EIAO-TM daytime construction noise criteria. Mitigation measures are therefore required to alleviate the adverse construction noise impact from this Project.

4.7.1.3 The total number of dwellings, classrooms and other noise sensitive receivers that would be exposed to noise impacts exceeding the criteria set in Annex 5 in the EIAO-TM were evaluated and it is estimated that a total of about 4,622 dwellings and 74 classrooms will be exposed to construction noise impact exceeding the relevant criteria set in Annex 5 in the EIAO-TM under unmitigated scenario.

4.7.2 Operational Phase

4.7.2.1 The fixed plant noise levels from the normal operation of the proposed underground water pumps (i.e. operation of one duty pump only) installed near mid-stream of TWN were predicted by adopting the methodology in Section 4.6.2. The predicted fixed plant noise levels under unmitigated scenario are summarised in Table 4.8 with details of the calculations given in Appendix 4.5.

Table 4.8 Summary of Predicted Fixed Plant Noise Levels from the Proposed Underground Pumps without Mitigation Measures

NAP ID	Description	Daytime / Evening Criterion, dB(A)	Predicted Fixed Plant Noise Level, Leq 30-min dB(A)
NAP8	Mei Wai House	55	11
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	55	14
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	55	15
NAP10	Peak House	50	19
NAP11	TWGHs Tsoi Wing Sing Primary School	55	19
NAP12	Buddhist Wong Wan Tin College	55	21
NAP13	Tung Lo Wan Village	50	17
NAP14	Lin Fung House	55	17
NAP15	Shing Ho Building	55	14

Note:

[1] The proposed underground water pumps would not operate during night-time (2300 – 0700 hours). Daytime / Evening criterion is therefore adopted.

4.7.2.2 For the proposed UV disinfection system, since detailed design information and noise specification have yet to be confirmed, the maximum permissible noise emission levels, taking into account cumulative noise levels from the proposed underground water pumps, were determined for future detailed design of the fixed plant to ensure compliance with the relevant noise criteria by adopting the methodology in Section 4.6.2. Same as the proposed underground water pumps, the proposed UV disinfection system would not operate during night-time (2300 – 0700 hours) and hence daytime / evening criterion is therefore adopted. The maximum permissible sound power levels (SWL) of the fixed noise sources of the Project for daytime / evening time have been presented in Appendix 4.5. Given that the proposed fixed plants are properly designed to meet the maximum permissible sound power level [i.e. 95 dB(A) for the fixed plants of the UV disinfection system], no adverse fixed plant noise impact would be anticipated.

4.8 Mitigation of Adverse Environmental Impacts

4.8.1 Construction Phase

4.8.1.1 The results of the construction noise assessment indicate that there would be exceedance of the construction noise criteria at most of NAPs in the absence of any mitigation measures. The various mitigation options listed below have thus been considered:

· Good site practices;

· Use of quality powered mechanical equipment (QPME) / quieter construction method; and

· Adoption of movable noise barriers / noise insulation fabric / noise enclosure

Good Site Practices

4.8.1.2 Although the noise mitigation effects are not easily quantifiable, and the benefits may vary with site conditions and operating conditions, good site practices are easy to implement and do not impact upon the works schedule. The site practices listed below should be followed during construction works:

· Only well-maintained PME to be operated on-site and should be serviced regularly during construction works;

· Silencers or mufflers on construction equipment should be utilised (if appropriate) and should be properly maintained during construction;

· Mobile plant, if any, should be sited as far away from NSRs as possible;

· Machines and plant (such as trucks) that may be in intermittent use should be shut down between work periods or should be throttled down to a minimum;

· Plant known to emit noise strongly in one direction should, wherever possible, be orientated to direct noise away from the nearby NSRs; and

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

Use of QPME / Quieter Construction Method

4.8.1.3 The use of QPME is considered a practicable means to mitigate the construction noise impact. QPME is defined as a PME having actual SWL lower than the value specified in the GW-TM. The type of QPME adopted in this assessment is for reference only. The contractors may adopt alternative QPME as long as it can be demonstrated that they would not result in construction noise impacts worse than those predicted in this assessment.

4.8.1.4 Quieter construction methods are also adopted, including use of road ripper for concrete breaking, use of hydraulic crusher for demolition of footbridge and silent piling by press-in method an alternative of traditional sheet piling. A sheet pile is clipped and pressed under the ground. Noise can be minimised by press-in sheet piles with drilling simultaneously for piling works at harder ground. The noise impact can also be further reduced as the piling works can be completed within the shorter duration by using this method.

4.8.1.5 For the use of QPME / quieter construction methods associated with the construction works, reference has been made to QPME list available on the EPD website, which provides the SWLs for specific QPME or PME specification published by equipment manufacturer. The SWLs of QPME adopted for the assessment are listed in Table 4.9.

Table 4.9 SWL of Quiet PME Adopted for Construction Noise Mitigation

Plant / Equipment	Ref Code	SWL, dB(A)
Hand-held Percussive Breaker	EPD-04329	99
Excavator/loader, wheeled/tracked	EPD-09127	99
Roller, vibratory	EPD-10387	94
Crane, mobile/barge mounted (diesel)	EPD-08825	101
Giken Piler and Power-pack	-	94^[1]
Concrete crusher, excavator mounted	OCUPME-008	103
Road ripper, mini robot mounted	OCUPME-026	97

Note:

[1] The SWL is reference to the approved EIA report "Tsim Sha Tsui Station Northern Subway" (AEIAR-127/2008). For the sound pressure level at 7 m from equipment, see website link below.. https://www.epd.gov.hk/epd/misc/construction_noise/contents/index.php/en/home2/quieter-construction-equipment/item/27-press-in-method.html

Use of Movable Noise Barriers / Noise Insulation Fabric / Noise Enclosure

4.8.1.6 Movable noise barriers that can be placed close to the construction equipment and moved along with the PME are effective for screening noise from NSRs. A typical design which has been used locally is a wooden framed barrier with a cantilevered upper portion of superficial density no less than 14 kg/m² on a skid footing with 25mm thick internal sound absorptive lining. This measure is particularly effective for low level zone of NSRs. A longer cantilevered top cover would be required to achieve screening benefits at upper floors of NSRs. The Contractor shall be responsible for the design and actual position of the movable noise barriers with due consideration given to the position and size of the PME, and the requirement of intercepting the line-of-sight from the NSRs to the PME, as well as ensuring that the barriers should have no opening and gap. The direct line-of-sight between the PME and the NSRs should be totally screened by a substantial barrier such that the PME will not be visible when viewed from any window, door or other opening in any façade of the NSR.  Reference shall be made to the EPD webpage[1] for the design of noise barrier.  Subject to the work arrangement in construction stage, the Contractor may propose other form of mitigation measures to achieve the full compliance. It is anticipated that properly designed noise barriers would achieve a 5 dB(A) reduction for mobile PME and a 10 dB(A) reduction for static PME. Acoustic mat with surface mass of not less than 7kg/m² would be used for plant items such as piler and a 10 dB(A) noise reduction is anticipated. The use of full enclosure has been considered in this assessment to shelter relatively static plant including ventilation fan. This type of enclosure is expected to provide approximately 15 dB(A) noise reduction.

4.8.1.7 The use of movable noise barrier for various items of PME adopted for noise assessment and typical arrangement for typical noise barrier arrangement for mobile PME are detailed in Appendix 4.6. The feasibility and practicability of the proposed provision of typical and cantilevered movable noise barriers / noise insulation fabric / noise enclosure have been confirmed by the Project Engineer.

Mitigated Construction Noise Levels

4.8.1.8 Having taken into account the noise reduction achieved by the above-mentioned mitigation measures, the predicted noise impacts at the NAPs are summarised in Table 4.10 and the detailed calculations are provided in Appendix 4.7.

Table 4.10 Summary of Mitigated Construction Noise Levels

NAP ID	Description	Land Use	Daytime Noise Criterion, Leq, 30 mins, dB(A)^[1]	Predicted Mitigated Maximum Construction Noise Levels, Leq, 30 mins, dB(A) ^[2]	Predicted Mitigated Maximum Construction Noise Levels with Additional Mitigation Measure, Leq, 30 mins, dB(A)
NAP1	Temporary Accommodations	Residential	75	62	NA
NAP2a	Mei King House, Mei Tin Estate	Residential	75	68	NA
NAP2b	Mei Chuen House, Mei Tin Estate	Residential	75	68	NA
NAP3	Mei Ying Court	Residential	75	67	NA
NAP4	Tower 1, Granville Garden	Residential	75	68	NA
NAP5	Block 2, Park View Garden	Residential	75	66	NA
NAP6	Mei Pak Court	Residential	75	64	NA
NAP7	Kwai Shing House, May Shing Court	Residential	75	68	NA
NAP8	Mei Wai House	Residential	75	71	NA
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Residential	75	71	NA
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Residential	75	65	NA
NAP10	Peak House	Residential	75	55	NA
NAP11	TWGHs Tsoi Wing Sing Primary School	Educational Institution	70/65	69	69 (65 during examination period)
NAP12	Buddhist Wong Wan Tin College	Educational Institution	70/65	65	NA
NAP13	Tung Lo Wan Village	Residential	75	53	NA
NAP14	Lin Fung House	Residential	75	66	NA
NAP15	Shing Ho Building	Residential	75	67	NA
NAP16	TWGHs Sin Chu Wan Primary School	Educational Institution	70/65	66	66 (65 during examination period)
NAP17	Man Lai Court	Residential	75	64	NA
NAP18	Planned Comprehensive Development Area Next to Tai Wai Station	Residential	75	55	NA

Notes:

[1] EIAO-TM noise criteria adopted: 75 dB(A) for residential dwelling; 70 dB(A) during normal school days / 65 dB(A) during examination period for educational institution.

[2] Underlined value indicates exceedance of EIAO-TM noise criteria of 65 dB(A) for educational institution during examination period. 

4.8.1.9 Based on the results in Appendix 4.7, the predicted construction noise levels arising from the Project at all NSRs selected for construction noise impact assessment would comply with the EIAO-TM daytime construction noise criteria, except during examination period of TWGHs Tsoi Wing Sing Primary School (NAP11) due to construction of dry weather flow intercepting channel and pipe laying along the nullah (Work Section 3, Group C-2) in November 2025 to March 2026, as well as of TWGHs Sin Chu Wan Primary School (NAP16) due to concurrent construction activities for construction of staircases and ramps (Work Section 1, Group B-2) and (connection work to the existing sewerage system (Work Section 1, Group C-1) in August to September 2024.

4.8.1.10 To further mitigate for the noise impact, the following construction restrictions during examination period of TWGHs Tsoi Wing Sing Primary School (NAP11) or TWGHs Sin Chu Wan Primary School (NAP16) are recommended:

· construction of dry weather flow intercepting channel and pipe laying along the nullah (Work Section 3, Group C-2) should not be undertaken within 30m from TWGHs Tsoi Wing Sing Primary School (NAP11) during examination period; and

· construction of staircases and ramps (Work Section 1, Group B-2) and (connection work to the existing sewerage system (Work Section 1, Group C-1) should not be undertaken concurrently within 30m from TWGHs Sin Chu Wan Primary School (NAP16) during examination period.

4.8.1.11 The recommended minimum separation distance between these construction activities and the schools during examination period has been confirmed by the Project Engineer to be suitable and practical for the construction programme. With the implementation of this additional mitigation measure, the predicted noise levels at NAP11 and NAP16 would comply with the EIAO-TM daytime construction noise criterion as summarised in Table 4.10. The detailed calculation with the implementation of this additional noise mitigation measure for NAP11 and NAP16 is presented in Appendix 4.8.

4.8.1.12 The results revealed that the construction noise levels from this Project at all NSRs would comply with the EIAO-TM daytime construction noise criteria after the implementation of the proposed noise mitigation measures. No adverse impact would be anticipated at any existing and planned/committed NSRs within 300m from the Project works area.

Cumulative Construction Noise Impact from Concurrent Projects within 300m Assessment Area

4.8.1.13 As mentioned in Section 4.5.1.4, potential cumulative construction noise impacts from “Drainage Improvement Works in Sha Tin and Sai Kung” on NAP17 and NAP18, “Revised Trunk Road T4 in Sha Tin” on NAP8 to NAP17 and “Joint-user complex at Tsuen Nam Road, Tai Wai” on NAP14 to NAP18 would be anticipated.

4.8.1.14 The detailed construction programme and plant inventory for “Drainage Improvement Works in Sha Tin and Sai Kung” and “Joint-user complex at Tsuen Nam Road, Tai Wai” project are not available at the time of this EIA Study. Amongst the affected representative NSRs, NAP16 and NAP17 are located closest to “Joint-user complex at Tsuen Nam Road, Tai Wai” and “Drainage Improvement Works in Sha Tin and Sai Kung” respectively. Assuming that the construction noise impact from these concurrent projects would comply with the relevant noise criteria at these closest NSRs, maximum predicted cumulative construction noise levels at these representative NSRs are summarised Table 4.11 as the worst-case scenario. Likewise, based on the detailed construction noise impact assessment in the approved EIA of Revised Trunk Road T4 in Sha Tin (AEIAR-231/2021), maximum predicted cumulative construction noise levels at with this concurrent project are presented Table 4.11. Details of the cumulative construction noise impact assessment are presented in Appendix 4.9.

4.8.1.15 Based on the results in Appendix 4.9 and Table 4.11, the maximum predicted cumulative noise levels arising from the Project at all NSRs selected for construction noise impact assessment would comply with the EIAO-TM daytime construction noise criteria, except at Buddhist Wong Wan Tin College (NAP12) during examination period due to concurrent construction of this Project and Revised Trunk Road T4 during December 2025 to February 2026; as well as at TWGHs Sin Chu Wan Primary School (NAP16) during examination period of due to concurrent construction of this Project and Joint-user complex at Tsuen Nam Road, Tai Wai during January 2024 to April 2024 and July 2024 to October 2024.

4.8.1.16 It is anticipated that the most noisy construction works of these two concurrent projects would be the foundation works for the T4 viaducts with reference to the approved EIA of Revised Trunk Road T4 in Sha Tin (AEIAR-231/2021) and foundation works for Joint-user complex at Tsuen Nam Road, Tai Wai. As described in Section 4.5.1.2, the area of active work site of this Project would be limited and not be longer than 100m along the nullah at each work section. As such, the tentative construction programme and works at the interface area between the Project and these projects could be arranged efficiently through close liaison between the contractors to avoid construction works of respective works contracts to be carried out concurrently at the same interfacing areas during the examination period. Concurrent construction of this Project with Revised Trunk Road T4 should avoid examination period of Buddhist Wong Wan Tin College (NAP12) between December 2025 and February 2026; whilst concurrent construction of this Project with Joint-user Complex at Tsuen Nam Road, Tai Wai should avoid examination period of TWGHs Sin Chu Wan Primary School (NAP16) from January 2024 to April 2024 and July 2024 to October 2024. The Contractor should keep close communication with the operators of these schools to obtain the updated schedule of examination at the time of conducting the relevant construction works.

Table 4.11 Summary of Cumulative Construction Noise Levels with Concurrent Projects

NAP	Description	Land Use	Daytime Noise Criterion, Leq, 30 mins, dB(A)^[1]	Predicted Maximum Noise Level with Mitigation Measures from the Project	Cumulative Noise Impacts Considered			Maximum Cumulative Noise Levels with Concurrent Projects, dB(A)^[4]
					Joint-user complex at Tsuen Nam Road, Tai Wai ^[2]	Drainage Improvement Works in Sha Tin and Sai Kung ^[2]	Revised Trunk Road T4 ^[3]
NAP8	Mei Wai House	Residential	75	71	û	û	ü	71
NAP9a	Mei Yeung House, Mei Lam Estate (North Façade)	Residential	75	71	û	û	ü	71
NAP9b	Mei Yeung House, Mei Lam Estate (East Façade)	Residential	75	65	û	û	ü	65
NAP10	Peak House	Residential	75	55	û	û	ü	64
NAP11	TWGHs Tsoi Wing Sing Primary School	Educational Institution	70/65	69 (65 during examination period)	û	û	ü	69 (65 during examination period)
NAP12	Buddhist Wong Wan Tin College	Educational Institution	70/65	65	û	û	ü	66 (66 during examination period)
NAP13	Tung Lo Wan Village	Residential	75	53	û	û	ü	63
NAP14	Lin Fung House	Residential	75	66	ü	û	ü	69
NAP15	Shing Ho Building	Residential	75	67	ü	û	ü	69
NAP16	TWGHs Sin Chu Wan Primary School	Educational Institution	70/65	66 (65 during examination period)	ü	û	ü	69 (68 during examination period)
NAP17	Man Lai Court	Residential	75	64	ü	ü	ü	75
NAP18	Planned Comprehensive Development Area Next to Tai Wai Station	Residential	75	55	ü	ü	ü	75

Note:

N/A NAPs outside 300m from concurrent Project were not assessed.

[1] EIAO-TM noise criteria adopted: 75 dB(A) for residential dwelling; 70 dB(A) during normal school days / 65 dB(A) during examination period for educational institution.

[2] Amongst the affected representative NSRs, NAP16 and NAP17 are located closest to “Joint-user complex at Tsuen Nam Road, Tai Wai” and “Drainage Improvement Works in Sha Tin and Sai Kung” respectively. As the noise levels are not available for the two projects, it is assumed that the construction noise impact from these concurrent projects would comply with the relevant noise criteria at these closest NSRs.

[3] Cumulative construction noise impact assessment based on the detailed construction noise impact assessment in the approved EIA of Revised Trunk Road T4 in Sha Tin (AEIAR-231/2021).

[4] Details of the cumulative construction noise impact assessment are presented in Appendix 4.9.

4.8.1.17 With the implementation of the above recommended mitigation measures, the mitigated cumulative construction noise levels from the Project and nearby concurrent project at all representative NSRs would fulfil relevant noise control standards stipulated under Annex 5 of EIAO-TM. A construction noise management plan, which to verify the inventory of noise sources, and to assess the effectiveness and practicality of all identified measures for mitigating the construction noise impact of the project (including the use of quieter construction methods such as road ripper for concrete breaking, hydraulic crusher for demolition and silent piling by press-in method for sheet piles, etc., quieter powered mechanical equipment, noise barriers and noise enclosures as recommended in Section 4.8.1), would be prepared before commencement of construction works.

4.8.2 Operational Phase

4.8.2.1 As shown in Table 4.8, all the predicted fixed plant noise levels at the representative NSRs due to the operation of the proposed underground water pumps would comply with the fixed plant noise criteria. Likewise, provided that the fixed plants of the proposed UV disinfection system are properly designed to meet the maximum permissible SWL, no operational phase noise impacts would be anticipated. Nonetheless, the following best practices should be implemented as far as practicable to further minimise any potential impacts:

· Quieter plant should be chosen as far as practicable;

· Include noise levels specification when ordering new plant items;

· Locate fixed plant / louvres away from any NSRs as far as practicable;

· Locate fixed plant in walled plant rooms or in specially designed enclosures;

· Install direct noise mitigation measures including silencers, acoustic louvres and acoustic enclosure where necessary; and

· Develop and implement a regularly scheduled plant maintenance programme so that plant items are properly operated and serviced. The programme should be implemented by properly trained personnel.

4.9 Evaluation of Residual Impacts

4.9.1 Construction Phase

4.9.1.1 With the implementation of the recommended noise mitigation measures, construction noise levels at all representative NSRs would comply with EIAO-TM daytime construction noise criteria. No residual construction noise impact is anticipated.

4.9.2 Operational Phase

4.9.2.1 No residual noise impact is anticipated during the operational phase of the Project.

4.10 Environmental Monitoring and Audit

4.10.1.1 Noise monitoring is recommended as part of the environmental monitoring and audit (EM&A) programme for the construction phase of the Project to check compliance with the daytime construction noise criteria. A construction noise management plan, which to verify the inventory of noise sources, and to assess the effectiveness and practicality of all identified measures for mitigating the construction noise impact of the project, would be prepared before the commencement of construction works. Weekly site audit is also recommend to ensure the proper implementation of the recommended mitigation measures for daytime construction activities as part of the EM&A programme. Details of the EM&A requirements are provided in the EM&A Manual.

4.10.1.2 No adverse fixed plant noise impact is anticipated during the operation of the underground waterpump and UV disinfection system located beneath Shing Mun Tunnel Road by the bankside of mid-stream TWN. Commissioning tests should be conducted prior to operation of the Project to ensure fixed plant noise impact would comply with the relevant noise standards. No operational noise monitoring is therefore deemed necessary.

4.11 Conclusion

4.11.1.1 The assessment for the potential construction noise impact from the Project has been conducted. The assessment result indicated that the mitigated cumulative noise levels at all NSRs would comply with the noise criteria set out in the EIAO-TM with proper implementation of the proposed mitigation measures. No adverse noise impact would be anticipated during construction phase of the Project.

4.11.1.2 The noise impact associated with the operation of the Project has been assessed based on the plant inventory provided by the Project Engineer at the time of the assessment. Maximum allowable sound power levels for the fixed noise sources of the Project have been determined. The assessment result indicated that the predicted fixed plant noise levels at all representative NSRs would comply with the noise criteria. No adverse noise impact is anticipated during operational phase of the Project. Commissioning tests should be conducted prior to operation of the Project to ensure that the fixed plant noise impact would comply with the relevant noise standards.

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[1] https://www.epd.gov.hk/epd/misc/construction_noise/contents/index.php/en/road-works/item/74-mitigation-measures/157-construction-noise-barrier.html