PWP Item No. 4331DS
Outlying Islands Sewerage Stage 2 – South Lantau Sewerage Works
Environmental Impact Assessment Report
178711/B&V/0029/Draft H
July 2014 23 B&V / ERM
ANNEX 8A
Methodology for Baseline Noise Measurements
ENVIRONMENTAL RESOURCES MANAGEMENT
8A-1
8A1 BASELINE NOISE MEASUREMENTS
8A1.1 OBJECTIVE OF THE BASELINE NOISE MONITORING
The objective of the baseline noise monitoring is to provide up-to-date
baseline conditions of the noise environment of the Study Area for assessment
of potential environmental impacts caused by the Project activities and
recommendation of mitigation measures to mitigate such impacts.
8A1.2 STUDY AREA FOR NOISE ASSESSMENT
The Study Area for noise assessment is defined by a distance of 300 m from
the Project Boundary (Figure 1).
8A1.3 SCOPE OF WORKS & METHODOLOGY
To investigate the prevailing noise levels within the Study Area, continuous
24-hour noise measurements were made at selected monitoring stations. The
noise measurements were conducted with reference to the instrumentation,
calibration and measurement procedures as stated in the Technical
Memorandum for the Assessment of Noise from Places other than Domestic Premises,
Public Places or Construction Sites (IND-TM).
In case continuous 24-hour noise measurement is considered not practicable
due to inaccessibility of the designated monitoring locations, measurements
were carried out alternatively for a period of not less than two hours for each
of the daytime (ie, 0700 to 1900 hours), evening (ie, 1900 to 2300 hours) and
nighttime (ie, 2300 to 0700 hours) period.
8A1.3.1 Monitoring Parameters
The baseline noise level was measured in terms of the A-weighted equivalent
continuous sound pressure level (Leq). Leq (30 minutes) was used as the
monitoring parameter for the time period between 0700 and 1900 hours on
normal weekdays. For all other time periods, Leq (5 minutes) was employed as
the monitoring parameter for comparison with the Noise Control Ordinance
(NCO) criteria.
Supplementary information for data auditing and statistical results such as L10
and L90 were also obtained for reference.
8A1.3.2 Monitoring Equipment and Methodology
As referred to the requirements of the Technical Memorandum (TM) issued
under the NCO, sound level meters in compliance with the International
Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985
(Type 1) specifications were used for carrying out the noise monitoring.
Immediately prior to and following each noise measurement the accuracy of
ENVIRONMENTAL RESOURCES MANAGEMENT
8A-2
the sound level meter was checked using an acoustic calibrator generating a
known sound pressure level at a known frequency. Measurements were
accepted as valid only if the difference between calibration levels obtained
before and after the noise measurement is less than 1.0 dB.
Noise measurements were made in accordance with standard acoustical
principles and practices in relation to weather conditions. Noise
measurements were not made in the presence of fog, rain, wind with a steady
speed exceeding 5 ms-1 or wind with gusts exceeding 10 ms-1. The wind speed
were checked with a portable wind speed meter capable of measuring wind
speeds in m/s.
8A1.3.3 Monitoring Locations
The preliminary designated locations for baseline noise monitoring are listed
in Table 1.1 and shown in Figure 1.
Table 1.1 Preliminary Designated Locations for Baseline Noise Monitoring
ID Location Description
1 Shui Hau Village
2 Residences at Tong Fuk
3 Residences at Cheung Fu Street
4 Cheung Sha Ha Tsuen
5 San Shek Wan
6 Pui O Lo Wai Tsuen
7 Residences at Ham Tin
The monitoring location was normally at a point 1 m from the exterior of the
noise sensitive facade and be at a position 1.2 m above ground. If there is a
problem with access to the normal monitoring position, an alternative position
was chosen, and a correction to the measurement results was made. For
reference, a correction of +3dB(A) was made to free-field measurements.
The baseline noise monitoring was undertaken continuously for a period of 24
hours for one day at each location. The baseline noise levels were measured at
a minimum logging interval of 30 minutes for daytime (between 0700 and
1900 hours of normal weekdays) and 15 minutes (as three consecutive Leq, (5
minutes) readings) for evening time (between 1900 and 2300 hours on normal
weekdays), general holidays including Sundays (between 0700 and 2300
hours) and night-time (between 2300 and 0700 on all days). The Leq, L10 and
L90 were recorded at the specified interval.
Any non-project related construction activities in the vicinity of the
monitoring locations during the baseline monitoring were noted and the
source and location of such activities recorded.
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Figure no.
Checked
OUTLYING ISLANDS SEWERAGE STAGE 2SOUTH LANTAU SEWERAGE WORKS -
INVESTIGATION
THE GOVERNMENT OF THEHONG KONG
SPECIAL ADMINISTRATIVE REGIONDRAINAGE SERVICES DEPARTMENT
香港特別行政區政府渠務署
Title
B L A C K & VE AT C H H O N G K ON G L I M I T ED
File: T:\GIS\CONTRACT\0227541\Mxd\NSR\0227541_NSR.mxdDate: 25/7/2014
Study Area for Noise, Noise Sensitive Receivers and Prevailing Background Noise Measurement Locations
Figure 8.1a
Prepared
Date Scale0 1 20.5Kilometers´
Key
!( Noise Sensitive Receiver
300m Study Area
Project Boundary
Proposed Site of Pumping Station
Alternative Site of Pumping Station
Proposed Site of Sewage Treatment Works
Proposed Sewer
Proposed Submarine Outfall
Proposed Rising Main
Access Road Lantau Island
N1
N2
N4
N3
N5 N6
N8
N7 N10
N12
N11
N13 N15
N17
N14
N16
TONGFUK MIU
WAN
SHUI HAU WAN
CHEUNG SHA BEACH
PUI O WAN
ID Location Description 1 Shui Hau Village 2 Residences at Tong Fuk3 Residences at Cheung Fu Street4 Cheung Sha Ha Tsuen5 Cheung Sha Ha Tsuen (East of Beach)6 San Shek Wan7 Residences at Ham Tin
1. Shui Hau Village
2. Residences at Tong Fuk
6. San Shek Wan
3. Residences at Cheung Fu Street
5. Cheung Sha Ha Tsuen (East)4. Cheung Sha Ha Tsuen
7. Residences at Ham Tin