8.1             Introduction

8.1.1       This section further elaborates the requirements of EM&A for the construction and operation of the Project, based on the assessment results of various environmental issues.

8.1.2       The objectives of carrying out EM&A for the Project include the following:

·      to provide a database against which any short or long term environmental impacts of the Project can be determined;

·      to provide an early indication should any of the environmental control measures or practices fail to achieve the acceptable standards;

·      to monitor the performance of the Project and the effectiveness of mitigation measures;

·      to verify the environmental impacts predicted in this EIA;

·      to determine project compliance with regulatory requirements, standards and government policies;

·      to take remedial action if unexpected problems or unacceptable impacts arise; and

·      to provide data to enable an environmental audit.

8.1.3       The following sections summarise the recommended EM&A requirements.  Details of EM&A are provided in a stand-alone EM&A Manual.

8.2             Air Quality Impact

Construction Phase

8.2.1       The construction work will inevitably lead to dust (TSP) emissions, mainly from excavation, truck haulage and material handling.  It is predicted that the dust generated will exceed the hourly and daily criteria of 500 mg m-3 and 260 mg m-3, respectively, at air sensitive receivers from Sheung Wan to Causeway Bay.

8.2.2       Mitigation measures have been proposed and presented in Section 3.8.  With implementation of the proposed dust suppression measures, good site practices and comprehensive dust monitoring and audit, the TSP levels at all air sensitive receivers will comply with the dust criteria.

8.2.3       Dust monitoring requirements will be recommended in the EM&A Manual to ensure the efficacy of the control measures.

Operation Phase

8.2.4       Vehicle emissions during the operation of the CWB & IECL tunnel will generate major air pollutants such as NO2, CO and SO2.  Table 8.1 shows the air quality guidelines that should be attained and maintained inside a vehicle tunnel.

Table 8.1        Tunnel Air Quality Guidelines

Air Pollutants

Averaging Time

Maximum Concentration



Micrograms Per Cubic Metre (mg m-3)

Parts Per Million (ppm)


5 minutes




5 minutes




5 minutes



8.2.5       In addition, the visibility in the tunnel should be controlled to a level equivalent to an extinction coefficient of 0.005 per metre or less during any five-minute interval.

8.2.6       The control and monitoring requirements for a vehicle tunnel given in the EPD’s Practice Note on Control of Air Pollution in Vehicle Tunnels should be followed.  Effective control of air pollution within the tunnel section of the CWB & IECL requires proper supervision on the maintenance and operation of the ventilation system and the monitoring equipment.  Good preventive maintenance should be employed.  Appropriate measures are presented in the EM&A Manual.

8.3             Noise Impact

Construction Phase

8.3.1       Construction noise impacts from this Project, in addition to the concurrent construction tasks of other projects including CRIII and WDII projects, are expected at NSRs identified in this EIA.  Appropriate mitigation measures are required in order to alleviate the impacts to meet the EIAO-TM criteria.  Noise monitoring during construction phase will have to be carried out to ensure that such mitigation measures have been implemented properly. 

8.3.2       The construction activities will be carried out during the daytime (between 0700 and 1900 hours).  If there is construction work undertaken in restricted hours, measurements will be carried out during the following periods:

·        between 1900 and 2300 hours;

·        between 2300 and 0700 hours of next day; and

·        between 0700 and 1900 hours on Sunday or public holidays.

8.3.3       Noise measurement should be undertaken at all monitoring stations for a 30-minute period during the daytime and a 5-minute period during restricted hours when the noisiest activities are being carried out.  Type 1 sound level meters, which comply with the International Electrochemical Commission (Publications 651:1979 and 804:1985), must be used for carrying out the noise measurement.

8.3.4       Ad hoc noise monitoring should also be carried out if necessary.  To establish the prevailing background noise level, one Leq (30 minutes), obtained between 0700 and 1900 hours of a normal weekday, and three consecutive Leq (5 minutes) measurements, obtained from each monitoring period (between 1900 and 2300 hours; and between 2300 and 0700 hours), are required.

8.3.5       Baseline monitoring to establish the background noise environment will be required and should be carried out for at least 14 consecutive days prior to the commencement of the project.  During the construction phase, impact monitoring will be required in order to assess whether or not operations on site in compliance with construction noise criteria stipulated in EIAO-TM.

Operational Phase

Road Traffic Noise

8.3.6       Traffic noise monitoring should be carried out after the completion of CWB & IECL at NSRs located along the CWB & IECL and in the vicinity of the recommended direct mitigation measures.  The purpose of this monitoring is to ensure that the proposed mitigation measures are effective.  The Highways Department will be responsible for the operational phase monitoring.  Qualified environmental team should be employed to carry out the proposed monitoring. The parameters, monitoring equipment, locations and procedures are presented in detail in the EM&A Manual.

Fixed Plant Noise

8.3.7       Noise monitoring for ventilation shaft noise is recommended to carry out to ensure that the SWLs of the louvre meet the specified standard.  Noise measurements shall be made in accordance with the procedures outlined in the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places and Construction Sites, and shall be conducted when the ventilation buildings are operating at its maximum capacity.  Further information for fixed noise monitoring is addressed in the noise section of the EM&A Manual.

8.4             Water Quality Impact

8.4.1       The potential water quality impacts arising from the construction works for the CWB & IECL have been assessed.  As no reclamation will be undertaken directly for the CWB & IECL, the primary concern with regard to water quality will be the control of runoff during construction.  The water quality assessment has concluded that the potential water quality impacts could be controlled to comply with the WPCO standards by implementing the recommended mitigation measures.  No unacceptable residual water quality impact is expected.  Monitoring of marine water quality during the construction phase is therefore not considered necessary for the CWB & IECL site.

8.5             Waste Management

8.5.1       Waste management will be the contractor’s responsibility to ensure that all wastes produced during the construction of the CWB & IECL are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements.  The mitigation measures recommended in Section 6.7 should form the basis of the site Waste Management Plan to be developed by the Contractor at the construction stage.

8.5.2       It is recommended that the waste arisings generated during the construction activities should be audited periodically to determine if wastes are being managed in accordance with approved procedures and the site Waste Management Plan.  The audits should look at all aspects of waste management including waste generation, storage, recycling, transport and disposal.  An appropriate audit programme is to undertake a first audit near the commencement of the construction works, and then to audit quarterly thereafter.

8.6             Landscape and Visual


8.6.1       Checks should be carried out to ensure that programme of implementation and all design input proposed for both hard and soft landscape mitigation measures have been incorporated into the design and the tender package.  This would include tree survey report, tree felling application, design of noise barriers, design of screen and roadside planting, etc.  The requirements to preserve the existing trees will be clearly specified as contractual obligations for the contractor.  Design of ancillary buildings, portals, noise barriers and the elevated structures should seek approval from Advisory Committee on the Appearance of Bridges and Associated Structures (ACABAS).

During Construction

8.6.2       Monitoring by the Environmental Team (ET) and Independent Checker (Environment) (IC(E)) should be carried out to ensure the implementation of all landscape and visual mitigation measures and to ensure the organisation of works programme allows advance planting of screen and roadside planting.


8.6.3       Audit by the ET and IC(E) should be carried out to ensure all proposed mitigation measures have been completed, in accordance with the works programme.