5. Noise Impact Assessment

5.1. Introduction

This chapter presents the assessment of the potential noise impacts which may arise from the Project. Noise impacts associated with decommissioning works, site formation works, temporary drainage works and road works of the west portion and southern edge of the Middle Ash Lagoon are assessed.

5.2. Environmental Legislation, Policies, Plans, Standards, and Criteria

Noise impacts would be assessed in accordance with the criteria and methodology stipulated in the Technical Memorandum on Environmental Impact Assessment Process (EIAO (TM)) and the Technical Memoranda (TMs) under the Noise Control Ordinance (NCO).

The EIAO and NCO provide the statutory framework for noise control and assessment guidelines of noise impacts. Assessment procedures and standards and set out as listed below:

· Section 3.4.5, and Appendix D of EIA Study Brief (ESB-243/2012)

· Annex 5 and 13 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO (TM))

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

· TM on Noise from Construction Work in Designated Areas (DA-TM)

· TM on Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM)

General Construction Works during Restricted Hours

Under the GW-TM, the use of powered mechanical equipment (PME) for carrying out construction works during restricted hours (1900-0700 hours Monday through Saturday and at any time on Sundays and general holidays) would require a Construction Noise Permit (CNP). The Noise Control Authority will process a CNP application, if necessary, based on the NCO, the relevant technical memoranda issued under the NCO, and the contemporary conditions/situations.

General Construction Works during Normal Hours

Although the NCO does not provide statutory framework for noise control during normal working hours (0700-1900 hours, Monday to Saturday), Annex 5 of the EIAO (TM) specifies the construction noise limits for domestic premises, hotel, hostel, temporary housing accommodation, educational institution including kindergarten and nurseries, hospitals, medical clinics, homes for the aged, convalescent homes, place of public worship, libraries, court of law, performing arts centres, auditoria, amphitheatres, country parks, etc.

Table 5.1 Daytime Construction Noise Standards

Uses	Noise Standard (L_eq,30min dB(A))
Domestic Premises	75
Educational Institutions (normal periods)	70
Educational Institutions (during examination periods)	65

5.3. Identification of Assessment Area and Noise Sensitive Receivers (NSRs)

The Subject Site is located in a remote area which is originally part of the ash lagoon next to the Black Point Power Station without proper access road connecting to the nearby Nim Wan Road. There is a planned Sludge Treatment Faculties (STF) located to the east of the Subject Site which is currently under construction.

According to Annex 13 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO (TM)), noise sensitive receiver includes all domestic premises (including temporary housing), educational institutions (including kindergarten and nurseries), hospitals, medical clinics, homes for the aged, convalescent homes, places of public worship, libraries, courts of law, performing arts centres, auditoria, amphitheatres, hostels and country parks. As such, site offices for STF, IWMF and WENT landfill extension are not considered as noise sensitive receiver according to Annex 13 of the EIAO (TM).

As defined in Section 3.4.5.2 of the EIA Study Brief (ESB-243/2012), the assessment area shall be expanded to include NSRs at distances over 300 metres from the Project which are affected by the decommissioning and construction of the Project. Figure 5.1 shows the 300m study area boundary. Generally speaking, noise at distance beyond 300m from a noise source would not be significant. The existing NSRs were identified through desktop review and site survey. No planned NSR is identified within the areas in the vicinity of the West Portion of the Middle Ash Lagoon at Tsang Tsui, in accordance with Outline Zoning Plans. The key representative NSRs for noise assessment is given in Table 5.2 and the representative locations are shown in Figure 5.2.

Table 5.2 Representative Noise Sensitive Receivers (NSRs)

NSR	Description	Usage	Shortest Horizontal Distance to Subject Site Boundary (km)
NSR1	Lung Kwu Sheung Tan	Village Houses	3
NSR2	Ha Pak Nai	Village Houses	2

Noise sensitive receivers were not identified within 300m of the Subject Site. Nearest possible noise sensitive receivers identified include village houses at Lung Kwu Sheung Tan and Ha Pak Nai, which are located 3km and 2km away from the Subject Site. Village houses at Lung Kwu Sheung Tan are separated from the Subject Site by natural terrain, consisting of mainly hills and trees while village houses at Ha Pak Nai is separated by STF and existing WENT landfill site. With the large separating distance and presence of natural and manmade barrier, the noise impact from the Subject Site to the village houses would not be significant.

Aside from the identified noise sensitive receivers in Table 5.2, a temple was also located approximately 30m from the Subject Site. According to the latest site visit conducted on 11 December 2013, the temple entrance was covered by wild grass. Incense burner was covered in dust while Buddha worship supplies were removed, suggesting it was unattended for a period of time. There was no encounter with any acolyte or visitors during the course of the site visit. As such, it was believed that the temple was abandoned and thus not considered as a noise sensitive receiver. Photographic records of the Hung Shing Temple visit on 11 December 2013 are shown in Figure 3.2.

Detailed desktop study of government survey maps, the latest Outline Zoning Plan (OZP), Outline Development Plans, Layout Plans and other relevant published land use plans, including plans and drawings published by Lands Department and any land use and development applications approved by the Town Planning Board were also conducted to confirm that no statutory planned use in the area is known throughout the construction period of the Project. Notwithstanding, good site practices and noise management techniques as discussed in Section 5.4 below shall be implemented throughout the Project.

Section 2 has presented a detailed description of the key construction activities at the Subject Site. The construction would include the following activities:

· Site formation works including leveling of PFA surface followed by covering of 1m thick general fill above the final PFA surface to proposed site formation levels

· Formation of Construction Access Road by filling and leveling followed by layering of a 1m thick general fill above the final PFA surface to proposed levels

· Upgrading of existing access road

· Construction of retaining structure for slope stabilization along the edge of existing water channel near the north site boundary

· Installation of drainage pipes for discharging the surface water out of the site at the north-west corner of the Subject Site

· Installation of site hoarding and temporary surface drainage system

It is expected that works for the decommissioning, site formation, temporary drainage works and road works of the Project will be divided into several stages. Access road upgrade will be carried out concurrently with the fill import and handling, followed by backfilling and excavation and levelling works.

The above construction activities will involve the use of Powered Mechanical Equipment (PME) including: dozer, compaction roller, vibratory roller, and backhoe. The plant inventory and the respective Sound Power Levels (SWLs) are given in Appendix 5.1.

Assessment results indicate that, under “unmitigated” scenario, the construction noise levels at the NSRs are within the criteria. With reference to Appendix 5.1, the maximum unmitigated construction noise levels against the stipulated criteria at the NSRs are summarized in Table 5.3.

Table 5.3 Predicted Maximum Construction Noise Levels at the NSRs

NSR	NSR Description	Maximum Predicted Noise Level, dB(A)	Criteria	Compliance (Y/N)
NSR1	Lung Kwu Sheung Tan	46	75	Y
NSR2	Ha Pak Nai	49	75	Y

The assessment results have demonstrated that daytime noise criteria would not be exceeded by the predicted construction noise levels under the unmitigated scenario. Good practices for the control of noise emissions from construction sites are however still recommended to further reduce any potential nuisance.

5.4. Good Site Practices and Noise Management Techniques

Good site practice and noise management techniques are recommended to reduce any adverse construction noise impact from construction site activities on nearby NSRs.

Some of these precautionary measures are listed as follows:

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

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

· Plant known to emit noise strongly in one direction, should, where possible, be orientated to direct noise away from nearby NSRs.

5.5. Definition and Evaluation of Residual Environmental Impact

Residual environmental impact is the net impact remaining with the mitigation measures in place. With the incorporation of recommended mitigation measures for construction phase, no residual noise impacts are anticipated.

5.6. Identification and Evaluation of Operational Phase Environmental Impact

As defined in Section 2.5, operational phase shall be defined as the period when the decommissioning works as detailed in Section 2.6 are completed. The operational phase of the Project shall be an idle buildable land to cater any future developments by the government. Since the operational phase does not involve any equipment operation or human activities, adverse noise impacts is not expected.

5.7. Environmental Monitoring and Audit

Further details of the specific EM&A requirements are detailed in Section 12 of this Report and in the EM&A Manual along with event action plans and procedures for complaints.

5.8. Conclusion and Recommendations

The assessment has been conducted based on daytime noise criteria specified in the EIAO-TM. It is predicted that the construction noise impacts associated with the construction activities on the Project site would not exceed the criteria. No adverse construction noise impact is anticipated. Mitigation measures are proposed in Section 5.4 to further minimise construction noise impact to the environment.