1.
1.
2.
3.
NOISE
3.1.1
In
accordance with the EM&A Manuals, Leq (30min) monitoring is conducted at
least once a week when there are Project-related construction activities being
undertaken within a radius of 300 m from the monitoring stations. The
monitoring is conducted during the construction phase between 0700 and 1900 on
normal weekdays at the designated monitoring locations.
3.2
Monitoring Equipment
3.2.1
As referred to
the requirements of
the Technical Memorandum (TM) issued under the NCO, the
sound level meters in
compliance with the
International Electro technical Commission Publications 651: 1979 (Type 1)
and 804: 1985 (Type 1)
specifications should be used for carrying out the noise monitoring.
Immediately prior to and following each noise measurement, the accuracy of the
sound level meter should be checked using an acoustic calibrator generating a
known sound pressure level at a known frequency. The measurements may be
accepted as valid only if the difference between calibration levels obtained
before and after the noise measurement is less than 1.0 dB.
3.2.2
The
model of the noise monitoring equipment used is summarized in Table
3.1.
3.3.1
The
parameters and frequencies of impact noise monitoring is summarized in Table
3.2.
3.4.1
Noise
measurement should be conducted as the following procedures:
·
The monitoring station will set at a point
1m from the exterior of the sensitive receivers building façade and set at a
position 1.2m above the ground. (In case façade
measurement is not feasible on-site, a free field correction of +3dB(A) will be
applied.)
·
The battery condition was checked to ensure
good functioning of the meter.
·
Parameters such as frequency weighting,
the time weighting and the measurement time will set as follows:
§
frequency weighting : A
§
time weighting : Fast
§ measurement
time: 30 minutes
·
Prior to and after noise measurement, the
meter shall be calibrated using the calibrator for 94.0 dB at 1000 Hz. If the
difference in the calibration level before and after measurement is more than
1.0 dB, the measurement will considered invalid and repeat of noise measurement
is required after re-calibration or repair of the equipment.
·
Noise measurement should be paused during
periods of high intrusive noise if possible and observation shall be recorded
when intrusive noise is not avoided.
·
Noise measurements shall not be made in
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. Calibration certificate of
the anemometer is provided in Appendix D.
3.5.1
Maintenance
and calibration procedures should also be carried out, including:
·
The microphone head of the sound level meter
and calibrator should be cleaned with a soft cloth at quarterly intervals.
·
The sound level meter and calibrator
should be calibrated annually by a HOKLAS laboratory.
·
Relevant calibration certificates are
provided in Appendix D.
3.6
Monitoring Locations
3.6.1
In
accordance with the EM&A Manual, three noise monitoring locations, namely
CM1, CM2 and CM3 are covered under Contract No. SPW 07/2020 “Environmental Team
for Construction of Yuen Long Effluent Polishing Plant Stage 1”.
3.6.2
The
most updated locations are summarized in Table 3.3
and the locations of the noise monitoring stations shown in Figure
3.
3.7.1
The
schedule of noise monitoring in reporting month is provided in Appendix
E.
3.7.2
No
Action / Limit Level exceedance of location CM1, CM2 and CM3 was recorded for
construction noise in the reporting month.
3.7.3
During
the monitoring month, at CM2, road traffic from the squatter house at the west
of Yuen Long STW was observed, at CM3, road traffic from the Nam Sang Wai Road
was observed. No effect that arose from the other factors for CM1 was noted
during the current monitoring month.
3.7.4
No
raining and wind with speed over 5 m/s was observed during noise monitoring
according to the onsite observation. The weather conditions during the
monitoring month are provided in Appendix K.
3.7.5
The
noise monitoring data are summarized in Table 3.4.
Detailed monitoring data are presented in Appendix F.
3.7.6
The
Action and Limit Levels for noise impact monitoring have been set and are
presented in Appendix C.
3.7.7
The
Event and Action Plan for noise is given in Appendix H.
3.8.1
The
noise monitoring data was compared with the EIA predictions as summarized in Table 3.5.
3.8.2
The
construction noise monitoring results at CM1, CM2 and CM3 were below the Maximum
Predicted mitigated Construction Noise Level in the approved Environmental
Impact Assessment (EIA) Report (Register No.: AEIAR-220/2019).