Cause of Impact
The main source of noise during construction of the Aberdeen Channel Bridge and viaduct sections along the Wong Chuk Hang Nullah is the use of Powered Mechanical Equipment (PME).
The main source of noise during operation of the railway is from fixed plant and railway operations.
In order to reduce noise levels during construction, the following remedies will be applied:
- Ensuring that the noise standards set by the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) are met as far as practicable;
- Obtaining a Construction Noise Permit (CNP) for PME use in restricted hours;
- Implementing the works in phases to minimize the number of PME in use at any one time;
- Shutting down (or throttling down to minimum) noisy PME between work periods;
- Positioning PME so that noise is directed away from sensitive areas;
- Using silencers or mufflers on construction equipment;
- Using silencers in fan ventilation systems;
- Using well-maintained PME and ensuring that PME are regularly serviced during the construction stage;
- Using movable noise enclosures with PME, wherever possible;
- Using quieter PME, fitted with noise insulating fabric where relevant;
- Using temporary or permanent noise barriers/acoustic shields with PME wherever possible;
- Using stockpiles and other structures to screen noisy activities; and
- Conducting regular site audits to ensure that noise control measures are properly implemented.
In order to reduce noise levels during railway operation, the following remedies will be applied:
- Ensuring fixed plant meet the maximum permissible sound levels and including noise levels specifications when ordering new plant;
- Locating fixed plant in walled plant rooms, specially designed enclosures or a basement;
- Locating fixed plant/louvers away from any sensitive areas, where possible;
- Installing direct noise mitigation measures including silencers, acoustic louvers and acoustic enclosures where necessary; and
- Developing and implementing a plant maintenance programme so that equipment is properly operated and serviced.
Careful application of all the various remedies described above will result in the levels of noise during construction of the railway being reduced to minimum. However, due to the massive construction works being undertaken (particularly piling construction works), there will be minor noise exceedance at a few noise sensitive receivers during the construction phase.
Maximum use will be made of remedies such as quiet PMEs, temporary/movable noise barriers, noise enclosures/acoustic sheds, silencers, noise insulating fabric and noise insulating covers.
Applying the various remedies described above will result in the levels of noise from fixed plant and railway operation fully complying with the noise standards stipulated in the EIAO-TM and Noise Control Ordinance.