4. NOISE

4.1 Environmental Legislation, Policies, Plans, Standards and Criteria

4.1.1 This section presents the assessment results of the potential noise impacts on the vicinity from the proposed Roads D1, D8, D10 and the Extended Road P2 during the construction and operation phase.

4.1.2 As mentioned in Section 1.3, two separate assessments (with and without the possible future development) should be conducted to evaluate the potential noise impacts arising from the proposed roads during the construction and operation phases. Since for Assessment 1, it is assumed that there will be possible further development to the south of Road D1, in terms of the number of concurrent construction activities, this should be the worst case situation during the construction phase. Hence, only Assessment 1 is done for assessing the noise impact during construction phase.

Construction Noise

4.1.3 The Noise Control Ordinance (NCO) provides the statutory framework for construction noise control. Assessment procedures and standards are set out in four Technical Memoranda (TM) listed below:

· TM on Environmental Impact Assessment Process (EIAO-TM);

· TM on Noise from Construction Work other than Percussive Piling (TM1);

· TM on Noise from Percussive Piling (TM2);

· TM on Noise from Construction Work in Designated Areas (TM3);

4.1.4 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 7 p.m. and 7 a.m. or at any time on Sundays and a general holiday (i.e. restricted hours). Noise control on construction activities taking place at other times is subject to Annex 5 of EIAO-TM: Criteria for Evaluating Noise Impact. The noise limit is 75 dB(A) Leq (30 min) at the facades of dwellings and 70 dB(A) Leq (30 min) at the façade of schools (65 dB(A) during examinations).

4.1.5 Construction activities involving the use of PMEs in the restricted hours are prohibited unless the construction noise permit (CNP) has been obtained. A CNP will only be granted provided that the requirements stipulated in TM1 is complied with. ANLs are assigned depending upon the Area Sensitivity Rating (ASR) of the NSRs. The corresponding basic noise levels (BNLs) for evening and night time periods, are given in Table 4.1

Table 4.1 Construction Noise Criteria for Activity other than Percussive Piling

Time Period	Basic Noise Level (BNLs)
	ASR A	ASR B	ASR C
Evening (1900 to 2300 hours)^1	60	65	70
Night (2300 to 0700 hours)	45	50	55

4.1.6 Since it is expected that works at night and in general holidays will not be required, only Annex 5 of EIAO-TM: Criteria for Evaluating Noise Impact the daytime (0700 to 1900) is applicable.

4.1.7 Percussive piling works, if necessary, are required to apply for construction noise permit. TM2 sets out the requirements for working and determination of the permitted hours of operations. ANLs for percussive piling for different type of NSRs are shown in Table 4.2.

Table 4.2 Acceptable Noise Levels for Percussive Piling

NSR Window Type or Means of Ventilation	ANL, dB(A)
(i) NSR (or part of NSR) with no windows or other opening	100
(ii) NSR with central air conditioning system	90
(iii) NSR with windows or other openings but without central air conditioning system	85

Note: 10dB(A) shall be subtracted from the ANLs shown above for NSRs which are hospitals, medical clinics, educational institutes, courts and law or other NSRs which are considered by the Authority to be particularly sensitive to noise.

4.1.8 Effective from 1 October 1999, the use of diesel, pneumatic and/or steam hammers are not allowed to be used in Hong Kong. The permitted hours of operation for carrying out of percussive piling work not involving the use of diesel, pneumatic and steam hammers are listed in Table 4.3.

Table 4.3 Permitted Hours of Operation for Percussive Piling

Amount by which Corrected Noise Level (CNL) exceeds Acceptable Noise Level (ANL), CNL-ANL	Permitted hours of operation on any day not being a general holiday
10 dB(A) < CNL-ANL	0800 to 0900 AND 1230 to 1330 AND 1700 to 1800
0 dB(A) < CNL-ANL £ 10 dB(A)	0800 to 0930 AND 1200 to 1400 AND 1630 to 1800
CNL- ANL £ 0 dB(A)	0700 to 1900

4.1.9 Under the TM3, the use of five types of Specified Powered Mechanical Equipment (SPME) and three types of Prescribed Construction Work (PCW) within a designated area during restricted hours requires a valid CNP. The study area of this project is within the designated area, therefore, the operation of SPME includes hand-held breaker, bulldozer, concrete lorry mixer, dump truck and hand-held vibratory poker will be controlled. The PCW to be controlled are :

· Erecting or dismantling of formwork or scaffolding

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

· Hammering

4.1.10 In general, the CNP would not be granted for the carrying out of PCW within a designated area during the restricted hours. The CNP would be granted for the use of SPME during the restricted hours within a designated area when the CNL for all the SPME proposed to be used are 15 dB(A) lower than the ANL stipulated in the TM1.

Operational Noise

4.1.11 Annex 5 of EIAO TM : Criteria for Evaluating Noise Impact, defines the criteria for road traffic noise at various NSRs:

· 70 dB(A) at the facades of dwellings, hotels, offices;

· 65 dB(A) at the facades of schools, places of workship, courts of law; and

· 55 dB(A) at the facades of hospital.

4.2 Description of the Environment

Baseline Condition

4.2.1 TKO is a new town centre and continues to develop in recent years. It is expected that the traffic will increase and would bring increasing traffic noise to the receivers within the town centre.

4.2.2 The areas planned for development around Roads D1, D8, D10 and Extended Road P2, include Areas 65, 67, 72, 73, 74, 85, 86 and possible future development to the south of Road D1. Except for part of Area 85 being planned as an industrial area, other areas are planned to be residential areas with some educational institutes. It is expected that traffic noise from the above roads and other existing roads would be the dominant noise sources.

Sensitive Receivers

4.2.3 Existing and planned noise sensitive receivers (NSRs) including domestic premises and educational institutions have been identified for noise impact assessment and are described below.

Construction Phase

4.2.4 The work packages and the construction period for the road project comprise the following:

· Road D1 (2003-2006)

· Road D8 (2003-2006)

· Town Centre Link, Road D10 (2003-2007)

· Minor road junction improvement works at road junction of Road D10 / Wan Po Road, and road junctions along Roads D1 and D8 (2002-2009)

· Extended Road P2 / Future Road P2 (2003-2010)

4.2.5 The nearby concurrent construction sites which involve major activities in between the construction period of the work packages of the road project are:

· Cross Bay Link, Road D9 (2003-2011)

· Road D6 (2003-2008)

· Seawall construction for Road P2 (2004-2005)

· Minor road junction improvement works at road junctions of Road D9 / Wan Po Road, Road D6 / Wan Po Road, and road junctions along D4 and P2 (2002-2009)

· Water Supply Infrastructure (2003-2007/08)

· Area 86 (2000-2010)

· Area 65D and 67 (completed after 2007)

4.2.6 The worst year during the construction period was identified for assessment, taking into account the construction period of the work packages of the road project, and the concurrent construction activities in close proximity to nearby NSRs.

4.2.7 By Year 2005, all the work packages of the road project will have commenced. Apart from the construction works for Road D1, D8, D10 and the extended Road P2, concurrent projects from other nearby construction sites will include the construction of Area 86, Road D9, Area 65D and Area 67. As the worst case scenario, the reclamation / roads and drainage works for the possible future development to the south of Road D1 is also assumed to be taking place and is thus included in the construction phase assessment. The assumption is only indicative assumed for the purpose of this study.

4.2.8 The cumulative construction impact will not be addressed if the construction sites are farther than 300m from the NSRs.

4.2.9 For the construction of Road D1, the nearest NSRs would be in Area 51, Areas 65 B&C and Area 72. For the construction of Road D8, the nearest NSRs would be in Areas 72, 73 and 74. The NSRs in Areas 57, 72, 67 and possible future development to the south of Area 67 would be affected by construction of Extended Road P2. However, no NSRs are identified within the 300 m area from the site boundary during construction of Road D10, no construction noise assessment for Road D10 is undertaken.

4.2.10 A description of the representative NSRs during the construction of Roads D1, D8 and Extended Road P2 are summarized in Table 4.4. Locations of the NSRs are shown in Figure 4.1.

Table 4.4 Description of the representative Noise Sensitive Receivers in Worst Year Scenario

NSR ID	Description	Area No.	Population Intake	Affected By construction activities within 300m from NSR
NSR1	Planned School	65C	2006	D1, Area 65D Development
NSR2	Planned Residential	72	2000-2004	D1, D8, P2, Area 67 Development, Seawall construction & possible future development to the south of Road D1Reclamation, piling work for noise barriers
NSR3	Planned Residential	72	2000-2004	D8, P2, piling work for noise barriers
NSR4	Planned Residential	74	2002	D8, P2, pilling work for noise barriers
NSR5	Planned Residential	73	2002	D8, pilling work for noise barriers
NSR8	Planned Residential	51	2000	D1, piling work for noise barriers
NSR9	Planned Residential	57	2000	P2, pilling work for noise barriers
NSR10	Planned School	72	2000-2004	D1, D8, P2, Area 67 Development, piling works for noise barriers

Note: Piling work for noise barriers at Road D1 near Areas 65B & C would be completed before the respective population intakes.

Operational Phase

4.2.11 Future residential developments and schools in Areas 51, 55a, 57, 65, 67, 72, 73, 74, possible future development to the south of Road D1 and 86 would be affected by road traffic noise from Roads D1, D8, D10 and the extended Road P2. As mentioned in Section 1.3, since there will be possible further development to the south of Road D1, two assessments (assuming with and without the possible future development) would be undertaken to evaluate the traffic noise impacts from the proposed roads and thereby to determine appropriate noise mitigation measures.

4.2.12 For Assessment 1, it is assumed that there will be existing and planned development in the vicinity of the proposed roads, as depicted in the latest Tseung Kwan O OZP (Figure 2.1a), in addition, there will be further development to the south of Road D1. To ensure the potential traffic noise impact arising from the proposed roads is within the planning standards, existing and planned noise sensitive receivers are identified. However, since there is no available layout for the possible future development to the south of Road D1 at the time of conducting the EIA study, an indicative layout is adopted for the purpose of traffic noise assessment. It is assumed that there will be 10 residential developments and 4 schools, the indicative layout is depicted in Appendix 4.5. For Assessment 2, it is assumed there will only be committed development, i.e. existing and planned development as shown in the latest TKO OZP. The locations of representative existing / planned / indicative NSRs for traffic noise assessment are described in Table 4.5 and shown in Figure 4.2 and Figure A4.6 in Appendix 4.5.

Table 4.5 Description of Noise Sensitive Receivers during Operation Phase

Existing / Planned NSR ID	Description	Area No.	Assessment Floor	Population Intake
212, 216, 218-220	Planned Residential, R2	72	1,10,20,30 & 48/F	2000-2004
213-215, 247-251	Planned School	72	1,3 & 6/F	2000-2004
217	Planned Residential, R1	67A	1,10,20,30 & 40/F	2007
206-209	Planned Residential, R1	67B	1,10,20,30 & 40/F	2009
210-211	Planned School	67	1,3 & 6/F	2009
620-626, 624a	Planned Residential, R1	65D	1,10,20,30 & 40/F	2008
256-260	Planned School	65D	1,3 & 6/F	2008
261-271, 274-278	Planned Residential	65B	1,10,20,30 & 40/F	2005
830	Planned Residential	65A	1,10,20,30 & 40/F	2001
253-255	Planned School	65C	1,3 & 6/F	2006
272-273	Planned Residential, HOS	65C	1,10,20,30 & 40/F	2006
238-243	Planned Residential, R1	55A	1,10,20,30 & 45/F	2002
301-303	Planned Residential, R1	57	1,10,20,30 & 47-49/F	2002
221-225	Planned Residential	73	1,10,20,30 & 47-49/F	2002
229-234	Planned Residential	74	1,10,20,30 & 40/F	2002
829-830	Planned School	86	1,3 & 6/F	2004-2012
824-828	Planned Residential	86	1,10,20,30,56-57/F	2004-2012
829	Planned Residential	85	1,10,20,30,40/F	2006

* represents the commissioning date

Indicative NSR ID	Indicative Planning Description	Area No.	Assumed Assessment Floor	Assumed Population Intake
79-81, 93-94, 308-311	Residential		1,10,20,30 & 35/F	2011-2013
145-149	School	Possible future	1,3 & 6/F	2011-2013*
139-141	School	development to the	1,3 & 6/F	2011-2013*
150-154	School	south of Road D1	1,3 & 6/F	2011-2013*
123	School		1,3 & 6/F	2011-2013*
101-113	Residential		1,10,20,30 & 35/F	2011-2013

4.3 Assessment Methodologies

4.3.1 The quantitative models, calculation method and the input parameters in this study have been verified and agreed with the relevant government departments.

Construction Phase

4.3.2 As discussed in Section 4.1.2, it is assumed that there will be possible future development to the south of Road D1. Taking into account of the different construction period and population intake in residential areas, the worst case scenarios for the affected NSRs have been identified.

4.3.3 Since the population intake in areas within 300m from the site boundary of Road D10 would be after Road D10 completion, therefore, no adverse construction noise impacts are expected from construction of Road D10.

Powered Mechanical Equipment

4.3.4 Powered Mechanical Equipment (PMEs) for the different construction tasks are presented in Appendix 4.1A. Sound power levels (SWLs) of PME were taken from Table 3 of the TM on Noise from Construction Work other than Percussive Piling. A positive correction of 3 dB(A) was made to the calculated result in order to allow for facade effect.

4.3.5 Given the current construction programme, it is currently considered unnecessary to carry out evening or night time work. According to TM1, for any construction works planned during the restricted hours, the Contractor will be required to submit CNP applications to the Noise Control Authority and has the responsibility to ensure compliance with the NCO and relevant TM. Therefore, the potential noise impacts of construction works proposed within restricted hours are not formally assessed within this EIA.

4.3.6 The methodology outlined in the Technical Memorandum on Noise from Construction Works other than Percussive Piling was used for the assessment of construction noise. Notional noise sources for different construction areas were assumed in accordance with the Technical Memorandum. All items of powered mechanical equipment (PME) were assumed to be located at these notional source positions.

4.3.7 The assessment was carried out on the basis of cumulative sound power level (SWL) of PME likely to be used for each location and phase of the construction period in the vicinity of the receiver location. In order to predict noise levels as realistically as possible, PME was divided into groups required for each discrete construction task. The objective was to identify a worst case scenario representing those items of PME which would be in use concurrently at any given time. The sound pressure level of each construction task was calculated, depending on the number of plant, their frequency of operation, and their distance from receivers. The noise level at the NSR was then combined from concurrent construction tasks.

4.3.8 Construction tasks taking place within 300m of a given NSR at the same period were considered to contribute to the cumulative impact at that NSR. Noise sources from greater distances were excluded from the assessment. The minimum distances from the notional source point of each construction activity to the representative NSRs are given in Appendix 4.1B.

Operational Phase

4.3.9 Traffic noise was predicted using the methodology provided in the UK Department of Transport Calculation of Road Traffic Noise (CRTN) 1988. The assessment should be based on projected peak hour flows for the worst year within 15 years of commencement of operation. With the approval from Transport Department, Year 2030 traffic flow provided by the traffic consultant was adopted in the assessment. Year 2030 traffic flow diagram is included in Appendix 4.3.

4.3.10 Traffic speeds used in the model were the design speed for different road types. The design speed is 70 kmh^-1 for a primary distributor except at-grade Extended Road P2 and 50 kmh^-1 for district distributors and local roads. In general, traffic flows on local roads within the development areas are low and have limited potential for traffic noise impacts. Local roads were therefore not considered in the model.

4.3.11 The road network, proposed building layout and all other features that could have noise screening or reflective effects, were digitised in the road traffic noise model. The roads were divided into segments, each of which was assigned a road layout number. A road layout defines the road width, opposing traffic lane separation, road surface type and traffic mix, flow and road design speed. The segmentation and calculation process were carried out using the model ‘HFANoise’ (Halcrow Fox Associates).

4.3.12 Noise levels were calculated at each receiver point at five different elevations (i.e. 1^st floor, 10^th floor, 20^th floor, 30^th floor, 40^th floor and top floor) for the residential blocks. There is no calculation for ground floor level. For the schools, noise levels were calculated at three elevations (1^st floor, 3^rd floor and 6^th floor). The sample output file is provided in Appendix 4.2C.

4.3.13 For the purpose of this EIA study, existing roads are defined as roads that are unchanged by the proposed project except for possibly taking additional traffic. The new roads are defined as roads that are completely new including Roads D1, D8 and D10 and Extended Road P2. Computer plots from the traffic noise model are included in Appendix 4.2D and all road segments for New Road have been highlighted in the drawings. The future Road P2, which is extended from the D1/D8/P2 roundabout, is not defined as a new road in this assessment. Instead, it is defined as ‘New (Other roads)’ and appropriate noise mitigation measures would be proposed on this section to alleviate the traffic noise impacts, where necessary.

4.3.14 Application of low noise surfacing is assumed on the Extended Road P2 elevated section and future Road P2 where the speed limit is 70km/hr in unmitigated and mitigated scenarios.

4.4 Overview of Relevant Studies

4.4.1 Various planning studies have been conducted and are considered to be relevant to this study. The recommendations from these studies have formed the basis for this assessment. The following is an overview of some of the major studies, with the findings and recommendations, which would be used in this study.

Widening of wan po road – envrionmental impact assessment study

4.4.2 Widening of Wan Po Road EIA Study was completed in June 1997. In this study, low noise road surfacing was recommended on the section of Wan Po Road from road junction near Areas 50 & 51 and road junctions of Road D6/Wan Po Road. This recommendation will be applied in the unmitigated scenario.

Tseung kwan o development contract no. tk 42/96, engineering infrastructure in Tseung kown o town centre central – environmental impact assessment

4.4.3 This study was completed in September 1997. The proposed noise mitigation measures included two segments of deck-overs on Road D4 near Area 57 & Area 55 respectively, and low road noise surfacing on section of Road P2 from junction of Road D8/L463 to near junction of Road P2/D4 (as shown in Figure 4.3). These proposed mitigation measures would be applied in the unmitigated and mitigated scenarios.

MTR tseung kwan o LINE TSEUNG KWAN O area 86, comprehensive development area submission under section 16/4a toWn planning ordinance – environmental assessment

4.4.4 This planning study was completed in January 1999. The study concluded that the major noise source would be Cross Bay Link which pose noise impacts to the sensitive facades of residential blocks located at the south of the development site. Erection of noise canopies along the southern boundary of the CDA site has been proposed but 863 dwellings would still be affected by the residual noise impact. Adopting a self-protective design such as providing architectural fins, fixed windows and balconies at certain sensitive facades are recommended.

4.5 Environmental Impact Identification, Prediction and Evaluation

Construction Noise Assessment

Potential Impacts

4.5.1 Without mitigation, the predicted noise levels at all representative residential NSRs exceed the noise criteria (75dB(A)) by 1 – 9 dB(A). The predicted noise level at NSRs 1 and 10 exceeds the criteria for school (70 dB(A)) by 14 dB(A). The cumulative noise levels from different construction activities are shown in Table 4.6. Practical mitigation measures should be implemented in order to reduce noise levels to comply with the standard. Detailed results are shown in Appendix 4.1A.

Table 4.6 Predicted Unmitigated Construction Noise Levels at NSRs in Worst Year Scenario

Construction Activities	Predicted Construction Noise Levels, dB(A)
	NSR1	NSR2	NSR3	NSR4	NSR5	NSR8	NSR9	NSR10
Area to the south of Road D1 Reclamation	-	66.1	-	-	-	-	-	-
Seawall Construction	-	66.4	-	-	-	-	-	-
Road D1 Construction	83.3	71.9	-	-	-	74.1		70.5
Road D8 Construction	-	77.5	80.7	75.5	75.5	-	-	74.7
Road P2 Construction		78.0	70.3	70.7	-	-	74.9	78.5
Area 65D Development	76.9	-	-	-	-	-	-	-
Area 67 Development	-	70.0	-	-	-	-	-	70.9
Piling Work for Noise Barriers	-	77.5	80.7	75.5	75.5	70.9	72.8	79.4
Cumulative Noise Level, dB(A)	84.2	83.2	83.9	79.2	78.5	75.8	77.0	83.2

Note: The construction noise standard for NSRs 1 & 10 are 70 dB(A) and NSRs 2 – 5, 8 & 9 are 75 dB(A).

Operational Noise Assessment

4.5.2 The predicted unmitigated results at the representative NSRs are presented in Appendix 4.2A and the results are summarized and discussed in the following paragraphs.

Assessment 1 – Worst Case Situation (with possible future development to the south of Road D1)

Noise Sensitive Receivers at Area 51

4.5.3 No noise exceedance is predicted at the sensitive façade due to large set-back distance from Road D1, therefore, no direct mitigation measure is required.

Noise Sensitive Receivers at Area 55A

4.5.4 In Area 55A, only the predicted noise level at one façade (NSR 242) cannot comply with the traffic noise standard. However, the noise exceedance of this façade is due to existing roads. The new road contribution to the total noise level is not more than 1 dB(A) and the new road noise level is less than 70 dB(A). Therefore, direct mitigation measures are not considered for Area 55A.

Noise Sensitive Receivers at Area 57

4.5.5 Noise exceedance is predicted at the representative NSRs 301 - 303 in Area 57 due to existing roads and new roads respectively. Direct mitigation measures on Extended Road P2 in this study will be required.

Noise Sensitive Receivers at Area 65

4.5.6 Area 65A (Bauhinia Garden), which contains 8 residential blocks, is located next to Road D4. A 8-storey high carpark is located between the development and Road D4 to shield traffic noise, in addition to a deckover on Road D4 between Areas 65A and 51. One representative NSR which is the closest to Road D1 was selected for assessment. Results indicated that no non-compliance of noise criteria at the selected façade was predicted.

4.5.7 Area 65B, which contains 10 residential blocks, is bounded by Road D1 and existing Road D4. Results show that most facades facing Road D1 exceed the noise limit by 1-4 dB(A). The noise exceedances are due to the junction of Roads D1/D4 and Road D1. Direct mitigation measures on this section of Road D1 will be required.

4.5.8 No noise exceedance is predicted at the residential NSRs in Area 65C as they are located at least 100m away from Road D1 and the school in Area 65C has noise screening effect for these NSRs. However, the predicted noise levels at schools in Area 65C and D exceed the limit by 1 – 8 dB(A) due to Road D1. Direct mitigation measures on Road D1 are required.

4.5.9 Area 65D, which contains 6 residential blocks on a 5m high podium, is bounded by Road D1. Noise exceedance up to 9 dB(A) is anticipated at the NSRs facing Road D1, D10 and Roads D1/D10 roundabout.

Noise Sensitive Receivers at Area 67

4.5.10 Noise levels of residential NSRs at Area 67 exceed the traffic noise limit by 2-11 dB(A). The school facades also exceed the traffic noise criteria by 4-7 dB(A). Their exceedances are due to traffic noise from Extended Road P2 and Road D1. Noise mitigation measures will therefore be required for the affected NSRs.

Noise Sensitive Receivers near Road D8 (Areas 72, 73 & 74)

4.5.11 Sensitive facades at Area 72 will be affected by traffic noise from Road D8, Extended Road P2 and future Road P2. It is expected that noise levels of residential NSRs in Area 72 will exceed the traffic noise criteria by 1- 9 dB(A). Noise exceedances up to 10 dB(A) at school NSRs in Area 72 are also predicted.

4.5.12 The facades at Areas 73 and 74 would be affected by traffic noise from Road D8, Extended Road P2 and the existing Road D4. With the consideration of proposed 3m vertical barrier on the 13.4m high podium for Area 74 development in accordance with “Tseung Kwan O Area 74 South Development Traffic Noise Impact Assessment”, noise levels of up to 6 dB(A) above the traffic noise limit are predicted at the facades of the residential blocks in Areas 73 and 74A. Mitigation measures on Road D8 are recommended to alleviate traffic noise impacts.

Noise Sensitive Receivers at Area 85

4.5.13 One indicative NSR is selected for assessment and exceedance of noise criteria is predicted., mainly due to existing Wan Po Road. In addition, the new road noise levels are less than 70 dB(A) and the new road noise contribution is less than 1 dB(A). Therefore, no direct mitigation measure on Road D10 is recommended.

Noise Sensitive Receivers at Area 86

4.5.14 Noise exceedances up to 2 dB(A) are predicted at the residential receivers facing Road D10. The dominant noise source is the elevated Road D10 and the slip roads from at-grade Road D10 to elevated Road D10. Noise mitigation measures at Road D10 will therefore be necessary.

Noise Sensitive Receivers at possible future development to the south of Road D1

4.5.15 Possible future development to the south of Road D1 is assumed to contain 7 residential blocks which are located on the top of a 6m high podium. 13 indicated points (NSRs 101 – 113) are selected and are assessed. It is expected that the NSRs facing the junction of road D1/D10 would be affected by traffic noise from Road D1 and Road D10. A maximum noise level of 6 dB(A) above the relevant limit is predicted at the affected facades (NSR 102-104). Direct mitigation measures on roads would therefore be required.

4.5.16 Four schools are assumed on possible future development to the south of Road D1 and 14 indicated points are selected for assessment. Road D1 will be the major traffic noise source. A set-back distance from Road D1 of about 30m to the schools has been incorporated into the design. However, noise levels of up to 8 dB(A) above the relevant limit are still expected at schools near Road D1. The noise levels at the facades of schools far away from Road D1 would all comply with noise criteria due to a large set-back distance from Road D1 and the shielding effect from the another two schools. Direct mitigation measures will therefore be required to alleviate the noise impact to affected schools.

4.5.17 Possible future development to the south of Road D1 is assumed to contain 10 residential blocks. It is assumed that a 16m high car-park building is located at the northern part of the site. 9 indicative points are selected for assessment. The predicted noise levels for facades facing Road D1 at mid and higher floors would exceed the limit . However, all the lower facades facing Road D1 would comply with traffic noise criteria due to the shielding effect from the possible car-park building. The noise levels for facades (NSRs 79-81, 308-311) facing Extended Road P2, future Road P2 and Road D8 are predicted to exceed the limit by 1-4 dB(A). Direct mitigation measures are recommended on roads to alleviate the traffic noise impacts.

Assessment 2 – Committed Development

4.5.18 The predicted noise levels at NSRs in Areas 51, 55A, 57, 65, 67, 72, 73, 74 and 86 are the same as that in Assessment 1. Detailed explanation is presented in Section 4.5.3 to 4.5.12.

4.5.19 Since it is assumed that there will be no future development to the south of Road D1, the impacts on the indicative NSRs in the possible future development are not assessed.

4.6 Mitigation of Adverse Environmental Impacts

Construction Noise Assessment

Quieter PMEs

4.6.1 Quieter construction plant is recommended in order to reduce the noise levels. Examples of silenced PME taken from the BS 5228: Part:1 1997, which are known to be used in Hong Kong, are shown in Appendix 4.1B.

4.6.2 With the use of quieter equipment, the overall noise levels at NSRs could be reduced by 1 - 6 dB(A), depending on the type of construction activities. The list of PME recommended +is shown in Appendix 4.1A and predicted noise levels with mitigation are shown in Table 4.7. Detailed results are shown in Appendix 4.1B. Results indicate that noise exceedances are still predicted at NSRs 1-3 and 10 in worst year scenario. Further mitigation measures will therefore be required.

Table 4.7 Predicted Mitigated Construction Noise Levels at NSRs in Worst Year Scenario (Using Quieter Plant)

Construction Activities	Predicted Construction Noise Levels, dB(A)
	NSR1	NSR2	NSR3	NSR4	NSR5	NSR8	NSR98	NSR10
Possible future development to the south of Road D1 Reclamation	-	66.1	-	-	-	-	-	-
Seawall Construction for the future Road P2	-	66.4	-	-	-	-	-	-
Road D1 Construction	79.2*	67.9*	-	-	-	74.1	-	66.5*
Road D8 Construction	-	74.0*	77.3*	72.1*	72.1*	-	-	71.3*
Road P2 Construction	-	71.9*	64.2*	64.6*	-	-	74.9	72.5*
Area 65D Development	71.2*	-	-	-	-	-	-	-
Area 67 Development	-	64.4*	-	-	-	-	-	65.3*
Piling Work for Noise Barriers	-	70.5*	73.7*	68.6*	68.6*	63.9*	65.9*	72.5*
Cumulative Noise Level, dB(A)	79.9	78.4	79.0	74.2	73.7	74.5	75.4	77.5

Note: The construction noise standard for NSRs 1 & 10 are 70 dB(A) and NSRs 2 – 5, 8 & 9 are 75 dB(A)

* using quieter plant

Movable Noise Barrier

4.6.3 In order to alleviate the construction noise impacts on the affected NSRs 1-3 and 10, movable noise barriers are recommended for particular plant during construction of Roads D1, D8 and P2, in addition to Areas 65D and 67B development. It is expected that a movable noise barrier with a cantilevered upper portion (5m high with 1.5m cantilevered length at least) and imperious plywood screen with density no less than 7kg/m² on a skid footing, located close to the noise generating part of the PME can produce at least 5 dB(A) or up to 10 dB(A) noise screening, depending on whether the line of sight could be blocked by the barriers when viewed from the NSRs. The Contractor can propose alternative type of barrier during construction with the same equivalent of noise reduction. The noise reduction of each plant considered in the assessment is listed in detail in Appendix 4.1A.

4.6.4 The fully mitigated noise levels of NSRs are shown in Table 4.8. Maximum further noise reduction up to 7 dB(A) in cumulative noise levels at NSRs is expected with the implementation of movable noise barriers.

Table 4.8 Predicted Mitigated Construction Noise Levels at NSRs in Worst Year Scenario (Quiet Plant + Movable Noise Barrier)

Construction Activities	Predicted Construction Noise Levels, dB(A)
	NSR1	NSR2	NSR3	NSR4	NSR5	NSR8	NSR9	NSR10
Possible future development to the south of Road D1	-	66.1	-	-	-	-	-	-
Seawall Construction for the future Road P2	-	66.4	-	-	-	-	-	-
Road D1 Construction	71.7#	67.9#	-	-	-	74.1	-	59.5#
Road D8 Construction	-	66.2#	69.3#	72.1*	72.1*	-	-	63.8#
Road P2 Construction		71.9*	64.2*	64.6*	-	-	74.9	63.0#
Area 65D Development	64.7#	-	-	-	-	-	-	-
Area 67 Development	-	64.4*	-	-	-	-	-	59.0#
Piling Work for Noise Barriers	-	64.7#	67.9#	68.6*	68.6*	63.9*	65.9*	66.7#
Cumulative Noise Level, dB(A)	72.5	75.2	72.4	74.2	73.7	74.5	75.4	70.3

Note: The construction noise standard for NSRs 1 & 10 and NSRs 2 – 5, 8 & 9 are 70 dB(A) and 75 dB(A) respectively

* using quieter plant

# Implementation of movable noise barrier and using quieter plant

Reducing the Number of Plant Operating close to NSRs

4.6.5 With the use of quiet plant and movable noise barriers, noise impacts from construction activities are still predicted at NSR 1. It is recommended to restrict the number of particularly noisy plant operating within certain parts of the site that are very close to the NSR 1. The use of this measure will only be applied to the construction works of Road D1 near NSR 1.

Table 4.9 Predicted Mitigated Construction Noise Levels at NSRs in Worst Year Scenario (Quiet Plant + Movable Noise Barriers + Limiting No. of PMEs)

Construction Activities	Predicted Construction Noise Levels, dB(A)
	NSR1	NSR2	NSR3	NSR4	NSR5	NSR8	NSR9	NSR10
Possible future development to the south of Road D1	-	66.1	-	-	-	-	-	-
Seawall Construction	-	66.4	-	-	-	-	-	-
Road D1 Construction	68.2@	67.9*	-	-	-	74.1	-	59.5#
Road D8 Construction	-	66.2#	69.3#	72.1*	72.1*	-	-	63.8#
Road P2 Construction	-	71.9*	64.2*	64.6*	-	-	74.9	63.0#
Area 65D Development	64.7#	-	-	-	-	-	-	-
Area 67 Development	-	64.4*	-	-	-	-	-	59.0#
Piling Work for Noise Barriers	-	64.7#	67.9#	68.6*	68.6*	63.9*	65.9*	66.7#
Cumulative Noise Level, dB(A)	69.8	75.2	72.4	74.2	73.7	74.5	75.4	70.3

Note: The construction noise standard for NSRs 1 & 10 is 70 dB(A) and NSRs 2 – 5, 8 & 9 are 75 dB(A).

* using quieter plant

# Implementation of movable noise barrier and using quieter plant

@ Using quieter plant, movable noise barrier and limit no. of PMEs

4.6.6 The predicted noise level at NSR1 is 69.8 dB(A) which meets the construction criteria of 70 dB(A) during normal period. During examination period , further reducing the number of noisy PMEs or re-scheduling the construction tasks is proposed, in addition to the recommendation stipulated in para 4.6.7, the noise level at NSR1 should comply with the noise criteria of 65 dB(A).

4.6.7 With the implementation of the above mentioned mitigation measures discussed above, the construction noise levels at all representative NSRs are predicted to comply with the noise standard stipulated in EIAO-TM. Table 4.10 shows the summary of predicted cumulative noise levels at all NSRs.

Table 4.10 Summary of Predicted Cumulative Construction Noise Levels at NSRs

NSR	Without mitigation	Mitigation A	Mitigation B	Mitigation C
1	84.2	79.9	72.5	69.8
2	83.2	78.4	75.2	-
3	83.9	79.0	72.4	-
4	79.2	74.2	-	-
5	78.5	73.7	-	-
8	75.8	74.5	-	-
9	77.0	75.4	-	-
10	83.2	77.5	70.3

Note: Mitigation A – Quieter PME

Mitigation B – Quieter Plant + Movable Noise Barrier

Mitigation C – Quieter Plant + Movable Noise Barrier + Limit no. of PMEs

4.6.8 There are also many good site practices that would serve to reduce noise impacts further. The recommended measures include:

· Noisy equipment and activities shall be sited by the contractor as far from sensitive receivers as is practical.

· Intermittent noisy activities shall be scheduled to minimize exposure of nearby NSRs to high levels of construction noise.

· Idle equipment shall be turned off or throttled down.

· Noisy equipment shall be properly maintained and used no more often than is necessary.

· Construction activities shall be planned so that parallel operation of several sets of equipment close to a given receiver is avoided;

· Where possible, the numbers of concurrently operating items of plant shall be reduced through sensitive programming; and

Ÿ A noise monitoring programme shall be instigated.

4.6.9 A rigorous EM&A programme should be undertaken, which would focus on those NSRs of particular concern, in order to identify and rectify any problems. A recommended EM&A programme has been presented separately in the EM&A Manual.

Operational Phase Assessment

Assessment 1 – Worst Case Situation (With possible future development)

4.6.10 In the following text, reference has been made to several types of direct mitigation measure (DMM) on roads. The proposed DMM include the following barrier types to reduce traffic noise impact:

Road D1 (With the development to the South of Road D1)

· Two sections of deckover between the future development to the south of Road D1 and Area 67B and between the future development to the south of Road D1 and Area 65D.

· Two vertical barriers of 5m height on the north edge and central divider of Road D1, east of the junction with local road L652 (noise protection for Area 67B).

· 5.5m high vertical barrier with 4m cantilever length at 90 degrees to the horizontal on the north edge of Road D1, west of junction with local road L651 (noise protection for Area 65D)

· Vertical barrier of 5m height on the central divider of Road D1, west of junction with local road L651 (noise protection for Area 65D).

· Cantilever barrier (6m high and 7.5m wide over the carriageway) (See Figure A4.4c in Appendix 4.4) at Road D1/D10 roundabout.

· Two vertical barriers of 5m height, located behind the footpath, adjacent to Area 65 schools.

· 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D1 adjacent to Area 65D.

· Three sections of 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D1 northbound adjacent to Areas 65B and 65C.

Road D8

· 5.5m high vertical barrier with 4.5m cantilever length at 45 degrees to the horizontal on Road D8 northbound near Area 72 residential development.

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Road D8 northbound near Area 72 residential development.

· 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D8 southbound near Area 72 school.

Road D10

· Vertical barrier of 4m height on elevated Road D10 westbound near Area 86.

· Sections of 5.5 m high vertical barrier with 2m cantilever length at 45 degrees to the horizontal on the westbound at-grade section and elevated Road D10 leading to the junction of Wan Po Road.

· Vertical barrier of 5m height near the possible future development to the south of Road D1.

Extended Road P2 (at grade)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) northbound near Area 72 school.

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) southbound near Area 67.

· 6m high and 7.5m wide over the carriageway (See Figure A4.4c in Appendix 4.4) on Extended Road P2 (at-grade) southbound and part of section of Extended Road P2 (at-grade)/Road D1 roundabout near Area 67.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) northbound near Area 72 and south of the roundabout.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal at the west side of Extended Road P2 (at-grade) southbound near possible future development to the south of Road D1.

· 5m high vertical barrier at Extended Road P2 (at-grade) southbound near possible future development to the south of Road D1.

Extended Road P2 (Elevated)

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Road P2 (elevated) northbound near Area 72.

· 5m vertical high barrier on Road P2 (elevated) southbound near 67 schools.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (elevated) southbound near Site 67R1 and the possible future developments to the south of Road D1.

· 5m high vertical barrier at central divider of Extended Road P2 (elevated) near Area 67

· A Y-shape cantilever barrier (5m high vertical barrier with 3.5m cantilever lengths on both direction at 45 degrees to the horizontal) at the central divider of Extended Road P2 (elevated) near the possible future development to the south of Road D1.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (elevated) northbound near Area 72 and south of the roundabout.

4.6.11 To the south of Area 66, the future land use is assumed to be schools. Therefore, two sections of 8m high dual-purpose boundary walls behind the Open Space are proposed for indicative assessment. Since the land use in future development to the south of Road D1 is not confirmed yet, implementation of the proposed 8m high boundary walls need to be reviewed in the future study of the possible development and would not be included in this Project.

4.6.12 The proposed DMM mentioned in the above paragraphs are shown in Figures 4.3, 4.4 and 4.5. The recommended barriers can be in the form of concrete, transparent panel or soil berms, and this would be considered in the detailed design stage. The proposed noise barriers would not be less than 7 kg/m². Typical section of noise barriers and enclosures are included in Appendix 4.4 and subject to detailed design. Alternative design of noise barriers and enclosures may also be proposed.

4.6.13 Some existing NSRs at Area 72, planned NSRs at Area 67 and the indicative NSRs in the possible future development to the south of Road D1 are predicted to exceed the noise criteria due to cumulative impacts from proposed new roads and Future Road P2. In order to achieve full compliance for these areas, noise mitigation measures are also proposed on future Road P2. However, the following proposed measures are just for reference only and will not be implemented in this project as Future Road P2 is out of the scope of this study. All measures recommended for future Road P2 should be reviewed in the future EIA study for Future Road P2.

Future Road P2 (at-grade)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the future Road P2 (at-grade) northbound near Area 72 and south of the roundabout.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the west side of the future Road P2 (at-grade) southbound near possible future development to the south of Road D1.

· 5m high vertical barrier on the future Road P2 (at-grade) southbound near the possible future development to the south of Road D1.

Future Road P2 (elevated)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the future Road P2 (elevated) southbound near the possible future developments to the south of Road D1.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on future possible Road P2 (elevated) northbound near Area 72 residential development

· A Y-shape cantilever barrier (5m high vertical barrier with 3.5m cantilever lengths on both direction at 45 degrees to the horizontal) at the central divider of the future Road P2 (elevated) near the possible future development to the south of Road D1.

· 5m high vertical barrier at the central divider of future Road P2 (elevated) near the possible future development to the south of Road D1.

4.6.14 The predicted mitigated results are presented in Appendix 4.2B and the results are discussed in the following paragraphs.

Noise Sensitive Receivers at Area 51

4.6.15 No noise exceedance is predicted at the representative NSR in the unmitigated scenario, therefore, no mitigation measure is required for this area.

Noise Sensitive Receivers at Area 55A

4.6.16 In Area 55A, only the predicted noise level of one façade (NSR 242) cannot comply with the traffic noise standard. However, the noise exceedance of this façade is due to existing roads. The new road contribution to the total noise level is not more than 1 dB(A) and the new road noise level is less than 70 dB(A). Therefore, no further direct mitigation measures are required.

Noise Sensitive Receivers at Area 57

4.6.17 Noise exceedance is still predicted at NSRs 301 and 303. However, it is by existing roads. The new road contribution to the total noise level is not more than 1 dB(A) and the new road noise level is less than 70 dB(A). Therefore, no further direct mitigation measures are required.

Noise Sensitive Receivers at Area 65

4.6.18 No noise exceedance is predicted at the representative façade of Area 65A residential development, therefore no mitigation measures are required for this area.

4.6.19 For Area 65B, NSR 262 at lower floors is predicted to exceed the traffic noise standard by 1-2 dB(A). However, the noise exceedances are dominantly due to the existing road. The noise contribution from the new Road D1 is not more than 1 dB(A) and new road noise level is less than 70 dB(A), so no further direct mitigation measures will be recommended.

4.6.20 For the school facades in Areas 65 C and D, with the proposed noise mitigation measures, no noise exceedance is expected.

4.6.21 Road D1 and the Road D1/D10 roundabout would be the dominant noise sources to Area 65D. By assuming a 5m podium design for the residential development and by adopting cantilever barriers on Road D1, noise exceedance is predicted at most of the NSRs in this area since the NSRs are too close to the noise sources. Deckover or full enclosure is therefore considered to be the most effective mitigation measures on Road D1 to alleviate the traffic noise impact. Considering that a deckover would allow pedestrians to better utilise the facility than a full enclosure over the road in this case, deckover on Road D1, spanning between the possible podiums of the development on either side of the road is felt to be the most suitable option at this stage (see Figure A4.4f in Appendix 4.4). In view of providing adequate clearance over the road, the deckover will be located at +15mPD. Since the podium level of Area 65D is located at +10mPD, a wall or an alternative structure will be located along the southern edge of the podium in order to provide at least a top height of approximately +15mPD and the deckover structure would then be cantilevered from this structure.

4.6.22 Further to deckover on Road D1 between Area 65D and area to the south of Road D1, one cantilever barrier (5.5m high with 4m cantilever length at 90 degrees to the horizontal) and a 5m high vertical barrier are proposed on the Road D1 eastbound and the central divider near Area 66. The objective of these measures is to alleviate the traffic noise impacts from other sections of Road D1 on the westernmost facades.

4.6.23 Traffic noise from Road D1/D10 roundabout is another noise source to the southern facades at Area 65D. Four options of cantilever barrier/deckover were proposed to abate the substantial noise impact from the D1/D10 roundabout on Area 65D. The proposal of the four options has been circulated to relevant departments to seek for their views. The four options and the constraints are listed as follows:

	Proposed options	Constraints
1.	Construct a deckover spanning from the podium in Area 65 and supported on columns located on the internal embankment of the roundabout.	Effect of the supporting columns on the motorist’s sightlines
2.	Construct a cantilever structure from the podium in Area 65 and provide support with columns located on the podium, and connected to the edge of the cantilever using supporting cables.	Engineering constraint since it would only be possible to cantilever a length of 12 to 15m rather than approximately 24m as required.
3.	Similar to option 2, but in order to minimize the difficulty from the engineering side, the footpath and Area 65D podium have to be located to being directly next to the roundabout.	visual impact
4.	Construct a smaller cantilever structure 6m high and 7.5 wide over the carriageway with additional support at the toe of the embankment.	Canyon effect to the pedestrians at the footpath.

4.6.24 In view of engineering constraints and safety concern, Options 1 to 3 are insurmountable. Option 4 is finally chosen and is proposed as the mitigation measures for the D1/D10 roundabout.

4.6.25 With the adoption of deckover, cantilevered barrier and vertical barrier on Road D1 and the cantilever barrier at Road D1/D10 roundabout, no exceedance was predicted at all facades of the assumed layout in Area 65D residential buildings. Figure 4.8 shows the planning constraints (non-sensitive building zone and set-back distances) required for Area 65D. In the future, if the developer decides to have noise sensitive uses within the current non-building zone, a separate noise impact assessment will have to be prepared to demonstrate that full compliance of the traffic noise standard can be achieved.

Noise Sensitive Receivers at Area 67

4.6.26 With the provision of noise mitigation measures on Road P2, deckover on Road D1 between Area 67B and area to the south of Road D1, in addition to 5m high vertical barriers on Road D1 eastbound and central divider near Area 66, no noise exceedance was predicted at representative residential NSRs and school facades at Area 67. Since the assessment was based on the assumed building layout to achieve full compliance, the planning constraints for Area 67B development (non- sensitive building zone and set-back distance) are shown in Figure 4.9. Similar to Area 65D, if the future developer intends to have noise sensitive uses within the non-building zone, a separate noise impact assessment will be required to demonstrate that full compliance of the traffic noise standard can be achieved.

Noise Sensitive Receivers at possible future development to the south of Road D1

4.6.27 With the proposed mitigation measures, the noise levels of most indicative school facades are predicted to comply with traffic noise criteria. Only four facades (NSRs 148, 149, 153 and 154) are found with exceedance of the noise standard. No noise exceedance is predicted at indicative residential NSRs in this area. Since layout for the assessment in this study in indicative only, the proposed 8m high dual-purpose boundary walls at the school lot boundary are for reference only. It is recommended that the proposed mitigation measures for the planned school in future development to the south of Road D1 to be investigated based on the future layout.

Noise Sensitive Receivers near Road D8 (Areas 72, 73 and 74)

4.6.28 Cantilever barriers are proposed on Road D8 to alleviate the traffic noise impacts. Since bus bays are located at Road D8 northbound and southbound, sections of cantilever barrier near bus bay would be located behind the footpath, while others are located at the kerb side of the road. With the proposed mitigation measures, the noise level of NSR 220 at low and mid floors would exceed the traffic noise standard in Area 72 dominantly due to existing road noise levels. Since the new road noise contribution in the overall noise levels is not more than 1 dB(A) and the new road noise levels are less than 70 dB(A), no further direct mitigation measures on Road D8 would be recommended.

4.6.29 For the schools in Area 72, the predicted noise levels at NSRs 213, 247, 249, 250, 251 and 252 are non-compliant with the noise standard. Except the noise exceedance at the top floors of NSRs 213 and 249 owing to both noise sources from new roads and existing roads, the new road noise contribution at other affected NSRs is less than 1 dB(A) and the total new road noise levels are less than 65 dB(A). Since the exceedance at top floors of NSRs 213 and 249 was caused by traffic noise from the road merging section and exits where the erection of barriers are not feasible, no further direct mitigation measures are proposed on the new roads. Indirect technical remedies such as air conditioning and glazing windows would be provided to the top floors of NSRs 213 and 249.

4.6.30 The noise levels at some NSRs in Areas 73 and 74A still exceed the traffic noise standard by 1-5 dB(A) due to existing roads. New road contribution in the overall noise levels is not more than 1 dB(A) and the new road noise levels are less than 70 dB(A). Therefore, no further mitigation measures will be recommended.

Noise Sensitive Receivers at Area 85

4.6.31 Since the exceedance at the indicative NSR is major due to existing Wan Po Road in addition to the new road noise levels are less than 70 dB(A) and the new road noise contribution is less than 1 dB(A), no direct mitigation measures on Road D10 is recommended.

Noise Sensitive Receivers at Area 86

4.6.32 The mitigated noise levels for all residential and school facades facing Road D10 are predicted to comply with the traffic noise limit.

Assessment 2 – Committed Development

4.6.33 In the following text, reference has been made to several types of direct mitigation measure (DMM) on roads. The proposed DMM include the following barrier types to reduce traffic noise impact:

Road D1 (Without the development to the South of Road D1)

· A semi-enclosure (5.5 m high with 7m cantilever length at 90 degrees to the horizontal) located behind the amenity area on Road D1 eastbound adjacent to Area 67B.

· A semi-enclosure (5.5m high with 11m cantilever length at 90 degrees to the horizontal) located behind the footpath near Road D1 eastbound near Area 67B bus-bay.

· A semi-enclosure (5.5m high with 10m cantilever length at 90 degrees to the horizontal) on the central divider of Road D1 adjacent to Area 67B.

· Two vertical barriers of 5m height, located behind the footpath, on the north edge and the central divider of Road D1, east of the junction with local road L652 (noise protection for Area 67B).

· A semi-enclosure on Road D1 eastbound, located behind the footpath, west of the junction with local road L651, adjacent to Area 66 (noise protection for Area 65D)

· 5.5m high vertical barrier with 4m cantilever length at 90 degrees to the horizontal at the kerb side of Road D1 eastbound adjacent to Area 65D.

· A semi-enclosure (5.5m high with 11m cantilever length at 90 degrees to the horizontal) on Road D1 central divider adjacent to Area 65D.

· Cantilever barrier (6m high and 7.5m wide over the carriageway) at Road D1/D10 roundabout.

· Two vertical barriers of 5m height, located behind the footpath, adjacent to Area 65 schools.

· Vertical barrier of 6m height located at the back of footpath, at the entry of Road D1 to L654, adjacent to Area 65D schools.

· 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D1 adjacent to Area 65D.

· Three sections of 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D1 northbound adjacent to Areas 65B and 65C.

Road D8

· 5.5m high vertical barrier with 4.5m cantilever length at 45 degrees to the horizontal on Road D8 northbound near Area 72 residential development.

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Road D8 northbound near Area 72 residential development.

· 5.5m high vertical barrier with 2.5m cantilever length at 45 degrees to the horizontal on Road D8 southbound near Area 72 school.

Road D10

· Vertical barrier of 4m height on elevated Road D10 westbound near Area 86.

· Sections of 5.5 m high vertical barrier with 2m cantilever length at 45 degrees to the horizontal on the westbound at-grade section and elevated Road D10 leading to the junction of Wan Po Road.

4.6.34 The proposed barriers on Extended Road P2 and the future Road P2 are as follow: .

Extended Road P2 (at grade)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) northbound near Area 72 school.

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) southbound near Area 67.

· Cantilever barrier (6m high and 7.5m wide over the carriageway) (See Figure A4.4c in Appendix 4.4) on Extended Road P2 (at-grade) southbound and part of section of Extended Road P2 (at-grade)/Road D1 roundabout near Area 67.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (at-grade) northbound near Area 72 and south of the roundabout.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal at the west side of Extended Road P2 (at-grade) southbound near possible future development to the south of Road D1.

· 5m high vertical barrier at Extended Road P2 (at-grade) southbound near possible future development to the south of Road D1.

Extended Road P2 (Elevated)

· 5.5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Road P2 (elevated) northbound near Area 72.

· 5m vertical high barrier on Road P2 (elevated) southbound near 67 schools.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (elevated) southbound near Site 67R1 and the possible future developments to the south of Road D1.

· 5m high vertical barrier at central divider of Extended Road P2 (elevated) near Area 67

· A Y-shape cantilever barrier (5m high vertical barrier with 3.5m cantilever lengths on both direction at 45 degrees to the horizontal) at the central divider of Extended Road P2 (elevated) near the possible future development to the south of Road D1.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on Extended Road P2 (elevated) northbound near Area 72 and south of the roundabout.

4.6.35 Some noise barriers are proposed at Future Road P2 to protect some existing NSRs at Area 72 and planned NSRs at Area 67. As mentioned in Section 4.6.13, the following proposed measures are just for reference only and will not be implemented in this project as Future Road P2 is out of scope of this study. All measured recommended for future Road P2 should be reviewed in the future EIA study for Future Road P2.

Future Road P2 (at-grade)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the future Road P2 (at-grade) northbound near Area 72 and south of the roundabout.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the west side of the future Road P2 (at-grade) southbound near possible future development to the south of Road D1.

· 5m high vertical barrier on the future Road P2 (at-grade) southbound near the possible future development to the south of Road D1.

Future Road P2 (elevated)

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on the future Road P2 (elevated) southbound near the possible future developments to the south of Road D1.

· 5m high vertical barrier with 3.5m cantilever length at 45 degrees to the horizontal on future possible Road P2 (elevated) northbound near Area 72 residential development

· A Y-shape cantilever barrier (5m high vertical barrier with 3.5m cantilever lengths on both direction at 45 degrees to the horizontal) at the central divider of the future Road P2 (elevated) near the possible future development to the south of Road D1.

· 5m high vertical barrier at the central divider of future Road P2 (elevated) near the possible future development to the south of Road D1.

4.6.36 The proposed DMM mentioned in the above paragraphs are shown in Figures 4.4, 4.6 and 4.7. The recommended barriers can be in the form of concrete, transparent panel or soil berms, and this would be considered in the detailed design stage. . The proposed noise barriers would not be less than 7 kg/m². Typical section of noise barriers and enclosures are included in Appendix 4.4 and subject to detailed design. Alternative design of noise barriers and enclosures may also be proposed.

4.6.37 The predicted mitigated results are presented in Appendix 4.2B and the results are discussed in the following paragraphs.

4.6.38 It is noted that the predicted results at Areas 51, 55a, 57, 65A, 65B, 65C, Area 67A, Area 67 school, Area 72 school, 73, 74, 85 and 86 are the same as that in the Assessment 1. Detail explanations on these areas are presented in the corresponding sections in Assessment 1.

Noise Sensitive Receivers at Area 65D

4.6.39 With the adoption of cantilever barrier and semi-enclosure on Road D1 eastbound and central divider, and the cantilevered barrier at Road D1/D10 roundabout, the predicted noise levels at representative NSRs comply with the traffic noise criteria based on the assumed building layout. Figure 4.8 shows the planning constraints (non-sensitive building zone and set-back distances) for Area 65D. A separate noise impact assessment will be required if the future developer plans to have noise sensitive uses within the current non-sensitive building zone to demonstrate that full compliance of the traffic noise standard can be achieved.

Noise Sensitive Receivers at Area 67B

4.6.40 For Area 67B, no noise exceedance is predicted at representative NSRs with the adoption of semi-enclosure and barriers on Road D1 eastbound and central divider, and barriers at Extended Road P2 and Future Road P2. Since the assessment was based on the assumed building layout to achieve full compliance of the traffic noise standard, the planning constraints (a non-sensitive building zone and set-back distance) are defined in Area 67B, as shown in Figure 4.9. Similar to Area 65D, if the future developer intends to have noise sensitive use within the non-building zone, a separate noise impact assessment will be required to demonstrate that full compliance of the traffic noise standard can be achieved.

Noise Sensitive Receivers at Area 72

4.6.41 With the proposed mitigation measures, the noise level of NSR 220 at low and mid floors would exceed the traffic noise standard in Area 72 dominantly due to existing road noise levels. Since the new road noise contribution in the overall noise levels is not more than 1 dB(A) and the new road noise levels are less than 70 dB(A), no further direct mitigation measures on Road D8 would be recommended..

4.7 Definition and Evaluation of Residual Environmental Impacts

4.7.1 No residual impacts are expected at NSRs during construction phase after the implementation of the proposed noise mitigation measures.

4.7.2 During operational phase, with the implementation of all practical direct mitigation measures as proposed, there would still be some exceedance found at the existing, planned and indicative sensitive receivers. The non-compliance for existing NSR is dominantly due to existing traffic. Residual impacts from new roads would be found at some school facades where DMM are not practicable at the source, such as at road junctions. Further investigation during the detailed design stage should be carried out to assess the potential of adopting tailor-made building layout plans to reduce the exposure to traffic noise. Indirect technical remedies in the form of acoustic insulation and air conditioning may be used as a last resort when practical measures have been exhausted.

4.7.3 A summary for estimating the number of dwellings and classrooms that will be exposed to noise levels exceeding the EIAO-TM criteria in unmitigated scenario and mitigated scenario is listed in Table 4.11.

4.7.4 Table 4.11 Summary of Number of Non-compliance Dwellings and Classrooms

Area No.	Description	Number of Dwellings/ Classroom (including special rooms) for Assessment	Number of Dwellings/ Classrooms are non-compliance in Unmitigated Scenario	Number of Dwellings/ Classrooms are non-compliance in Mitigated Scenario
For Assessment 1 only
Possible future development to the south of Road D1 (NSRs 79-81, 93-94, 308-311)	Residential (Indicative)	1680	430	0
Possible future development to the south of Road D1 (NSRs 123, 139-141, 145-154) #	School (Indicative)	40	25	0
	School (Indicative)	40	0	0
	School (Indicative)	40	0	0
	School (Indicative)	40	22	20
Possible future development to the south of Road D1 (NSRs 101 – 113)	Residential (Indicative)	2816	210	0
For Assessment 1 and 2
72	Planned Residential, R2	3520	1496	0
72	Planned School	80	60	36@
67	Planned Residential, R1	3200	720	0
67	Planned School	40	10	0
65D	Planned Residential, R1	2240	760	0
65D	Planned School	80	60	0
65A#	Existing Residential	-	-	-
65B	Planned Residential	1920	505	40*
65C	Planned School	40	40	0
65C	Planned Residential, HOS	1280	0	0
55A	Planned Residential, R1	720	90	90*
57	Planned Residential , R1	376	138	80*
73	Planned Residential	1280	480	400*
74	Planned Residential	960	960	940*
85#	Planned Residential	-	-	-
86	Planned School	40	4	0
86	Planned Residential	2264	216	0

Note: * Exceedance due to existing road noise.

# An indicative point for assessment only.

@ Exceedance due to existing road noise / new road noise

4.7.5 No adverse secondary effects from the mitigation measures for construction and operational phases would be expected. No unacceptable residual impact would be anticipated after implementation of mitigation measures.