In this section, the requirements, methodology, equipment, monitoring locations, criteria and protocols for the monitoring and audit of noise impacts during construction and operation of the on-site concrete batching plant are presented.
At present, noise monitoring is carried out once a week at three locations. In order to have effective management of the site, continuous, on-site real-time monitoring is proposed at 4 noise monitoring stations, including the three current locations and one new station. All real-time monitoring data will be accessible whenever there is a need through dial up telephone line. This will also allow quick responses to complaints on environmental issues.
A database for all real-time monitoring data will be developed and updated on a daily basis. The data will be audited within 2 working days of sampling and the audited data will be posted onto the Web-site for public access two working days after sampling.
Noise
Noise level, Leq(30-mins), at every 30 minute interval between 0700-1900 hours and noise levels, Leq(5-mins), at every 5 minutes interval between 1900-0700 hours will be collected and posted on Website. As supplementary information for data auditing, statistical results such as L10 and L90 levels of the same intervals will be logged for internal reference only. They will not be posted onto the Website.
Sound level meters, type I model, will be installed on site for round-the-clock monitoring, Leq, L10 and L90 levels will be stored in the memory of the sound level meter which can be remotely accessed though dial-up lines. This will be done normally on a daily basis, or whenever necessary. A typical design of the noise monitoring station is illustrated in Figure B3 of Appendix B.
To protect the microphone from rain and sunlight, an outdoor shield shall be installed on the microphone to protect it against the effects of wind, rain and perching birds. Correction to the shield can be made though this is normally not necessary for such small value.
As referred to in the Technical Memorandum (TM) issued under NCO, sound level meters in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1) specifications shall be used for carrying out the noise monitoring. Immediately prior to and following each noise measurement the accuracy of the sound level meter shall be checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements may be accepted as valid only if the calibration level from before and after the noise measurement agree to within 1.0dB.
Noise measurements should not be made in the presence of fog, rain, wind with a steady speed exceeding 5 m/s or wind with gusts exceeding 10 m/s. The wind speed shall be checked with a portable wind speed meter capable of measuring the wind speed in m/s.
The ET is responsible for the provision of the monitoring equipment. He shall ensure that sufficient noise measuring equipment and associated instrumentation are available for carrying out the baseline monitoring, regular impact monitoring and ad hoc monitoring. All the equipment and associated instrumentation shall be clearly labelled.
Based on the EIA findings there may be residual impacts therefore potentially noise sensitive receptors have been identified. Table 3.1 shows the noise monitoring stations.
Table 3.1 Proposed Noise Monitoring Stations during Construction Works
|
Identification No. |
Description of NSR |
|
N1 |
No. 60 Sasson Road |
|
N2 |
Upper Kong Sin Wan Tsuen |
|
N3 |
Baguio
Villa |
|
N4 |
Pui Ying Secondary School |
a) Locations of the stations are indicated in Figure 2.1.
The monitoring station shall normally be at a point 1 m from the exterior of the sensitive receivers building facade and be at a position 1.2 m above the ground. If there is problem with access to the normal monitoring position, an alternative position may be chosen, and a correction to the measurements shall be made. For reference, a correction of +3dB(A) shall be made to the free field measurements. The ET shall agree with the ER on the monitoring position and the corrections adopted. Once the positions for the monitoring stations are chosen, the impact monitoring shall be carried out at the same positions.
Baseline levels shall be referred to the Baseline Monitoring Report of “Infrastructural Works for the Proposed Development at Telegraph Bay”.
Continuous noise monitoring shall be carried out at all the designated monitoring stations during the construction and operation phases of the concrete batching plant.
The Action and Limit levels for construction noise are defined in Table 3.2. Should non-compliance of the criteria occur, action in accordance with the Action Plan in Table 3.3, shall be carried out.
Table 3.2 Action/Limit Levels for Construction Noise
|
Time
Period |
Action
Level |
Limit
Level |
|
0700-1900 hours on normal
weekdays |
When
one documented complaint is received |
75* dB(A) |
|
0700-2300 hours on holidays;
and 1900-2300 hours on all other days |
60/65/70** dB(A) |
|
|
2300-0700 hours of next
day |
45/50/55** dB(A) |
* reduce to 70 dB(A) for schools and
65 dB(A) during school examination periods
** to be selected based on Area
Sensitivity Rating
Note : If
works are to be carried out during restricted hours, the conditions stipulated
in the construction noise permit issued by the Noise Control Authority have to
be followed.
Table 3.3 Event/Action Plan for Construction and Operation Noise
|
EVENT |
ACTION |
|||
|
ET |
IC(E) |
ER |
Contractor |
|
|
Action Level |
1.
Notify
IC(E) and Contractor; 2.
Carry
out investigation 3.
Report
the results of investigation to the IC(E) and Contractor; 4.
Discuss
with the Contractor and formulate remedial measures; 5.
Increase
monitoring frequency to check mitigation effectiveness; |
1. Review the analysed results submitted by the ET 2.
Review
the proposed remedial measures by the Contractor and advise the ER
accordingly 3.
Supervise
the implementation of remedial measures |
1.
Confirm
receipt of notification of failure in writing; 2.
Notify
Contractor; 3.
Require
Contractor to propose remedial measures for the analysed noise problem; 4.
Ensure
remedial measures are properly implemented. |
1. Submit noise mitigation proposals to IC(E); 2. Implement noise mitigation proposals. |
|
Limit Level |
1.
Notify
IC(E), ER, EPD and Contractor; 2.
Identify
source; 3.
Repeat
measurement to confirm findings; 4.
Increase
monitoring frequency; 5.
Carry
out analysis of Contractor’s working procedures to determine possible
mitigation to be implemented; 6.
Inform
IC(E), ER and EPD the causes & actions taken for the exceedances; 7.
Assess
effectiveness of Contractor’s remedial actions and keep IC(E), EPD and ER informed
of the results; 8.
If
exceedance stops, cease additional monitoring. |
1.
Discuss
amongst ER, ET and Contractor on the potential remedial actions; 2.
Review
Contractor’s remedial actions whenever necessary to assure their effectiveness
and advise the ER accordingly; 3.
Supervise
the implementation of remedial measures. |
1.
Confirm
receipt of notification of failure in writing; 2.
Notify
Contractor; 3.
Require
Contractor to propose remedial measures for the analysed noise problem; 4.
Ensure
remedial measures are properly implemented; 5.
If
exceedance continues, consider what portion of the work is responsible and
instruct the Contractor to stop that portion of work until the exceedance is
abated. |
1. Take immediate action to avoid further exceedance; 2. Submit proposals for remedial actions to IC(E) within 3 working
days of notification; 3. Implement the agreed proposals; 4. Resubmit proposals if problem still not under control; 5. Stop the relevant portion of works as determined by the ER
until the exceedances is abated. |
The EIA report has recommended noise control and mitigation measures during construction and operational phases.
Construction Phase
The Contractor shall be responsible for the implementation of these construction noise mitigation measures during the construction of concrete batching plant. The key measures are shown below
· Use of quiet type equipment including generator, excavator, mobile crane and vibration poker.
Operation Phase of the Development
During the operation of the concrete batching plant, the following mitigation measures are suggested,
§ Fully enclose the conveyor to unload the material to the aggregrate receiving hopper
§ Fully enclose the concrete mixer
§ Use of electric motor for mixing
§ Conduct all mixing and loading in fully enclosed area
§ Well maintain all concrete trucks
§ Perform regular maintenance works for plant equipment
The implementation schedule is also presented in Appendix C2. On the other hand, impact prediction review checklist (Appendix F2) should be employed to check the extent of discrepancy between the actual and the predicted impact at the designated monitoring stations. ET should estimate the efficiency of proposed mitigation and plan it carefully for the ongoing construction activities
If the above measure is not sufficient to restore the construction noise quality to an acceptable levels upon the advice of ET, the Contractor shall liaise with the ET on some other mitigation measures, propose to ER for approval, and carry out the mitigation measures.