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LCQ12: Noise generated by construction works of West Island Line

     Following is a question by the Hon Kam Nai-wai and a written reply by the Secretary for the Environment, Mr Edward Yau, at the Legislative Council meeting today (February 23):


     The construction works under the West Island Line (WIL) project commenced in July 2009, and some of the construction sites in the Central and Western District are very close to residential areas.  Some affected residents have relayed to me that noisy works of 75 dB(A) (measured over a 30-minute period) or less under the project may be carried out between 7am and 7pm each day from Monday to Saturday, causing immense nuisance to residents; as the construction works of the South Island Line (SIL) project are about to commence this year, the problem of noise pollution is of concern.  In this connection, will the Government inform this Council:

(a) of the number of complaints received by the authorities to date about noise nuisance related to the WIL project, and the monthly complaint figures, set out in a list, since the commencement of the project;

(b) of the method to measure the aforesaid noise level of 75 dB(A); which organisation chose the time and locations to make such measurements; whether residents were consulted; of the change in locations by the authorities for making measurements so as to collect noise data more effectively and accurately;

(c) of the result of the most recent noise measurements taken from the WIL construction works by the authorities, including where and when the measurements were made, and whether the readings have exceeded the standard prescribed in the Environmental Impact Assessment;

(d) of the function of the noise insulating fabric used in the project at present; of the correct way to use the noise insulating fabric in order to insulate noise; whether it will require the MTR Corporation Limited (MTRCL) to stop using noise insulating fabric and use noise enclosures instead;

(e) whether it will require MTRCL to change the time for carrying out those works which emit a high level of noise to after 9am; whether it knows the locations where such a change can be effected, so as to alleviate the nuisance to residents;

(f) what measures it has to enhance alleviation of the problem of nuisance caused by the noise of the aforesaid project to the residents nearby; and

(g) whether it knows how MTRCL has gained experience in handling noise pollution of the WIL project, and how it will strengthen noise insulation and improve the method for collecting information on noise pollution during the SIL project?



     To reduce impact on nearby residents, all major works of the WIL Project of the MTRCL are conducted underground.  Construction on ground level, which mainly involves works on stations and their entrances and exits, is usually carried out between 7am and 7pm on weekdays.  The said construction hours do not fall within the period subject to control under the Noise Control Ordinance (NCO).  However, as the WIL Project is a designated project under the Environmental Impact Assessment Ordinance (EIAO), MTRCL has completed the Environmental Impact Assessment Report as required by EIAO and prepared the Environmental Monitoring and Audit Manual (the EM&A Manual) according to the Environmental Permit approved by the Environmental Protection Department (EPD).  It has also installed monitoring equipment according to the actual site conditions and methods of construction.  

     The EM&A Manual sets out detailed requirements on the environmental monitoring procedures of the WIL Project, including the guideline on daytime noise limits.  In case the noise monitoring results of the works exceed the guideline limits, for example, when the noise level recorded at designated noise monitoring points set up in residential buildings exceeds 75 dB(A), MTRCL is required to take mitigation measures immediately until the noise level falls below the limits.

     Moreover, as stipulated in the Environmental Permit, during the construction period, MTRCL is required to make available to the public a monthly report on the results of noise monitoring carried out near the project sites, related complaints and the follow-up work.  These environmental monitoring and audit reports (EM&A Reports) are also uploaded to the websites of the MTRCL's WIL Project and EPD in a timely manner for public inspection.

(a) As at the end of January 2011, EPD had received a total of 31 noise nuisance complaints against the WIL Project. Detailed statistics is at Annex I.

     Upon receipt of each complaint, the EPD would conduct independent investigation under the NCO and the EIAO.  So far we have not detected any non-compliance with the relevant ordinances.  Meanwhile, the EPD, would immediately inform the holder of the environmental permit of the complaint and request activation of the monitoring system, collection of relevant environmental data and adoption of appropriate mitigation measures, if necessary, according to the EM&A Manual.

(b) According to the EM&A Manual of the WIL Project, MTRCL is required to measure and record the noise level at each designated noise monitoring point continuously for 30 minutes every week.  The measurements should take place between 7am and 7pm from Monday to Saturday when construction works are being carried out.  Subject to the actual circumstances, designated noise monitoring points are set up at locations which are most affected by the relevant construction noise as far as feasible.

     To further enhance noise monitoring, EPD has requested MTRCL's Environmental Team (ET) to review the locations, representativeness and arrangements of the current noise monitoring programme so as to address the residents' concerns.  It is understood that MTRCL will closely note the noise monitoring locations selected to ensure that more representative data are collected.

(c) Environmental monitoring and auditing mechanism and the EM&A Manual require MTRCL to conduct noise measurements at designated noise monitoring locations on a weekly basis. Noise data obtained shall then be audited and verified by the Independent Environmental Checker (IEC) before being recorded in the EM&A Report.  The latest verified noise monitoring results, which have been uploaded to the website of MTRCL's WIL Project for public information, are at Annex II.

(d) When carrying out construction works of WIL Project, MTRCL has adopted a number of noise mitigation measures, including the use of noise insulating fabric.  Noise insulating fabric is a proprietary product effective in noise reduction and is widely applied in construction industry abroad and locally. In addition, subject to site conditions, MTRCL also adopts other appropriate noise mitigation measures. For example, acoustic enclosures are used in construction sites at King George V Memorial Park, Praya Kennedy Town and Hill Road. For the site at the sitting out area at Belcher's Street outside The Belcher's, the noisy hydraulic rock drill is replaced by hand-held breakers.

(e) Current NCO and EIAO do not require construction works to start after 9am on weekdays.  Nevertheless, EPD has advised MTRCL to arrange for the more noisy works to commence at a later time in the morning, wherever possible, to minimise nuisance to the residents.  It is understood that the MTRCL has arranged certain noisy works to commence only after 8am in the WIL Project.  MTRCL will continue to minimise the noise impacts while keeping the works on schedule.

(f) To further reduce the potential impact to the residents, MTRCL will continue to closely monitor the effectiveness of current noise mitigation measures and make further improvements wherever practicable. In addition to implementing a series of noise mitigation measures as required in the environmental impact assessment report, MTRCL has also established various public communication channels, such as Projects Hotline, Community Liaison Group meetings and Information Centers for MTRCL to find out the situation in the community and strive to further reduce the project's impact. While closely monitoring the noise levels, MTRCL has also responded to the community's needs by, for example, drawing up a works schedule that caters for the operations of the schools and hospitals near the site so as to minimise the noise impact.  EPD has also stepped up the communication with the ET and the IEC to discuss various issues related to environmental monitoring and auditing to strengthen monitoring of the environmental impact.

(g) MTRCL has indicated that in planning the works of the South Island Line, it will refer to the experience gained in the WIL Project. Through regular communication, such as sharing of experience by staff involved in the two projects, MTRCL will review and formulate effective environmental protection measures and ensure that such measures are properly implemented.

     In addition, EPD has requested MTRCL to strengthen its communication with local residents through the Community Liaison Groups with a view to strengthening residents' understanding of the work at the site and its management, encouraging reflection of views to facilitate MTRCL's timely responses, so that works proposal acceptable to all parties can be reached through consultation and environmental monitoring approach can be optimised.

Ends/Wednesday, February 23, 2011
Issued at HKT 16:11


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