15. Noise and Vibration
This Chapter addresses Section 4.7 of the ToR. It describes the existing noise environment
that may be affected by the proposal. A description of the existing noise environment is
provided having regard for baseline noise contributors. The background levels and sources
of noise and vibration that may be affected by the proposal are also discussed.
The objectives for noise and vibrationcriteria are stated in respect of relevant standards
(ambient and ground level concentrations), relevant guidelines, and any relevant legislation.
15.1
Description of Environmental Values
15.1.1
Noise Sensitive Receivers
Potentially affected receivers and features on and around The Spit area are shown in
Figure 15-1.
The nearest occupied premises to the Project site is the Seaway Kiosk, a food outlet that
sells other miscellaneous products for recreational activities, and has an owner’
s apartment
in the same building. Its commercial nature (typical operating hours are 7:00 am – 5:00 pm)
and necessary proximity to car parking and the public thoroughfare, make it unreasonable to
treat as purely residential.
Apart from the Seaway Kiosk, the nearest residences to the site are on the western side of
the Broadwater along Marine Parade. Residences are a mixture of holiday and permanent
accommodation, mainly in unit or apartment blocks. The closest residences are
approximately 1.5 km from the terminal location, separated by Marine Parade and the
Broadwater.
The sand bypass jetty is also open to the public for an access fee. It is located to the east of
the kiosk.
Several open space and recreational facilities are located within the local area. Doug
Jennings Park is the nearest public open space to the Project, lying between the proposed
marina precinct and the cruise ship terminal. The Federation Walk trail runs the length of
The Spit between, and at varying distances from, Sea World Drive and Main Beach.
Labrador Park is on the western side of the Broadwater, approximately due west of Doug
Jennings Park.
Noise can also impact upon terrestrial and aquatic fauna. A representative of the local
birding group suggested that nesting in the area was not likely, due largely to the fact that
the area is a dog-walking area. The Environmental Protection Agency (2006) advised that
Humpback whales migrate along the coast, and there is anecdotal evidence to suggest
bottlenose dolphins frequent the area. Numerous fish and other marine species inhabit the
Seaway area, as identified in Section 16.
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Seaway
Seaway
Tower
Tower
Doug
Doug
Jennings
Jennings
Park
Park
Labrador
Labrador
Park
Park
)
)
Kiosk
Kiosk
)
)
)
)
)
)
Sand
Sand
Pumping
Pumping
Station
Station
Sand
Sand Jetty
Jetty
Sand
Sand
Pumping
Pumping
Station
Station
Hotels
Hotels &
&
Residences
Residences
Nara
Nara
Resort
Resort
Seaworld
Seaworld
%
0
250
500m
Scale 1:20,000
Source: GCCC
Projection: MGA94, Zone 56
Date Printed: 15/08/2006
File: G:\41\15762\GIS\Maps\SensitiveFeatures.wor
Size: A4
Copyright: This document is and shall remain the property of
GHD Pty Ltd.The document may only be used for the purpose
for which it was commissioned and in accordance with the
terms of engagement for the commission. Unauthorised use
of this document in any way is prohibited. 
Legend
Hotels & Residences
Park
NOTIONAL SEAWAY
PROJECT
Environmental Impact Statement
Figure 15-1. Potentially Affected
Receivers (Noise & Vibration)
15.1.2
Existing Acoustic Environment
15.1.2.1 The Spit (Doug Jennings Park and Surrounds)
The ambient noise environment around the site of the Project is a product of natural and
anthropogenic sources, the more dominant of which depending on the time of day, day of the
week, weather conditions and sea state conditions.
Anthropogenic sources include:
»
Seaway and Broadwater vessel traffic;
»
Road traffic and associated car parking and boat launching/retrieval activities;
»
Distant traffic on the Gold Coast Highway and other roads/streets in the Southport area;
»
Aircraft noise:
– Overflights by commercial airlines;
– Overflights by advertising aircraft and
– Sightseeing aircraft, including helicopter flights from Sea World.
15.1.2.2 Western Edge of Southport Broadwater
Existing ambient noise levels at the western edge of the Broadwater are dominated by local
traffic noise, as well as traffic noise from the nearby Gold Coast Highway. Vessel traffic on
the Broadwater and aircraft noise also contribute to ambient noise levels in the area.
15.1.2.3 Sea World / Nara Resort
The Sea World amusement park produces significant levels of noise internally during the
day, and is closed during the evening and night. Operating hours are 10:00 am – 5:00 pm
(gates closing at 5:30 pm). The Nara Resort is attached to the northern boundary of the Sea
World facility, and is adjacent to existing public boat ramp facilities.
15.1.2.4 Underwater Acoustic Environment
The underwater acoustic environment in the Seaway and Broadwater is presently dominated
by surf and vessel traffic. Sand pumping operations have been reported by local surfers to
cause perceptible vibration levels in the ocean near the jetty, which is expected to be
associated with audible noise underwater.
15.1.3
Ambient Noise Levels
15.1.3.1 Long Term Monitoring
Background noise monitoring was conducted over the course of approximately 1 week to
establish typical noise levels in the area of the potentially most affected receivers. Appendix
F provides graphical representations of noise levels and details of daily statistical noise
levels recorded.
The background noise levels for the day, evening and night time periods are provided in
Table 15-1. The noise logger was shifted from Whiting Street around the corner to Labrador
Street on Thursday 20 May 2004 due to security concerns. The data does not appear to be
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15-3
significantly different between the sites, which were approximately 100 m apart. The
ambient (LAeq) noise levels are shown in Table 15-2.
Table 15-1 Long Term Background Noise Levels9 (dB re 2x10-5 Pa)
Day
LA90 (Day)
Tuesday 18 May 2004
LA90 (Evening)
LA90 (Night)
44.3
40.5
Wednesday 19 May 2004
48.0
45.0
42.0
Thursday 20 May 2004
47.5
45.5
43.5
Friday 21 May 2004
45.7
44.2
42.5
Saturday 22 May 2004
48.9
41.4
36.5
Sunday 23 May 2004
43.5
43.3
37.5
Monday 24 May 2004
44.7
44.0
37.5
47
44
41
Rating Background Level
Table 15-2 Long Term Ambient Noise Levels (dB re 2x10-5 Pa)
Day
LAeq (Day)
Tuesday 18 May 2004
LAeq (Evening)
LAeq (Night)
55.0
50.4
Wednesday 19 May 2004
60.0
56.4
51.2
Thursday 20 May 2004
57.5
55.1
52.4
Friday 21 May 2004
59.0
59.4
55.8
Saturday 22 May 2004
61.5
52.9
54.8
Sunday 23 May 2004
60.4
55.0
50.7
Monday 24 May 2004
59.2
55.6
54.5
Planning noise level
60
56
53
9
Assessment Background Level’
s calculated for each time period (day, evening, night) for each 24 hour period
th
monitored using the 10 percentile method.
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15.1.3.2 Attended Noise Monitoring
Attended noise measurements were conducted on 22 May 2006 at the logger locations,
Labrador Park and Doug Jennings Park. Details of the noise measurements are provided in
Appendix F, with results summarised below in Table 15-3.
The background noise levels at Labrador Street and Labrador Park were both due mainly to
anthropogenic noise sources, however the background noise level at Doug Jennings Park
was surf noise. The LAeq and LA10 noise levels at Doug Jennings Park were mainly due to
vehicles and helicopters. Although The Spit is generally a recreational / open space area, it
is not regarded as being a low noise or particularly sensitive environment.
Table 15-3 Summary of Attended Noise Measurement Results
Location
Time
LAeq(10 min)
LA10(10 min)
LA90(10 min)
Labrador St (logger location)
12:40pm
-
-
44
Labrador Park
13:00pm
53
57
47
Doug Jennings Park
13:25pm
56
60
48
Notes:
-5
Readings in (decibels re 2x10 Pa) taken 22 May, 2005
15.1.4
Existing Vibration
15.1.4.1 Western Edge of Southport Broadwater
Existing vibration levels in this area are minimal, based on site observations exposing no
significant vibration sources. Large trucks may cause occasional transient perceptible
vibration or aircraft causing sound-induced vibration in some residences in the area,
however background vibration is considered to be negligible.
15.1.4.2 The Spit (Doug Jennings Park and Surrounds)
There are two (2) pumping stations on The Spit. The larger pump house is at the origin of
the jetty, and the smaller (low pressure) pump house is beside the existing boat ramp at the
northern end of the marine stadium.
The pump houses contain rotating machinery and will therefore produce some vibration
while in operation, however there is currently no perceptible ground vibration near the pump
houses.
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15-5
15.2
Potential Impacts
15.2.1
Airborne Noise
15.2.1.1 Overview
Noise is any unwanted sound in the environment, whether at work, in a residence, or
engaged in any range of recreational activities. The degree of annoyance is a complex
function of a multitude of factors, including but not limited to:
»
The sound pressure level experienced by the receiver;
»
The characteristics of the sound (tonal, impulsive, spectral frequency content);
»
The activity the receiver is engaged in (rest, conversation, sport etc); and
»
The attitude or preconception of the receiver to a particular noise source.
The above factors illustrate the focus of assessment being on the noise that reaches the
identified receivers. In order to determine this, however, properties of the sound source(s)
and the propagation path to the receiver(s) is required.
The sound power level is used to describe the amount of sound energy produced by a
source, and has the SI unit of Watts (W). By convention, the sound power level is often
reported as decibels (dB) with respect to a reference power of 1 pico Watt (10-12 W) i.e.
Sound Power Level = 10 x log10(W source/W reference)
The sound pressure level is the term used to describe the amplitude of the sound wave at
the receiver. Technically, sound pressure is measured in Pascals (Newtons per square
metre), although it is more commonly reported and recognised in decibels, as the pressure
squared with respect to a reference pressure of 20 micro Pascals squared i.e.
2
Sound Pressure Level = 10 x log10(Pmeasured2/Preference )
The above relationships allow for convenient calculation between the sound power level of a
source and the sound pressure level it produces in decibels.
The increases in measured sound pressure level resulting from the increases in the number
of equivalent sources is readily calculated using the following equation:
SPL2 = SPL1 + 10 x log10(no. of sources2/ no. of sources1)
This relationship facilitates estimates of increases in noise levels from increases in road
traffic, for example.
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15.2.1.2 Propagation
Sound travels away from the source as a vibration through the air. Propagation of sound
into the space around a source depends mostly on the following three factors:
»
The shape of the source;
»
The directional characteristics of the source, if any (the source may project more sound in
certain directions than others); and
»
The shape of the volume of air the sound can propagate into.
The shape of the source can be complex, however at sufficient distances, most sources can
be described adequately as point, line, or plane sources.
Directional characteristics describe the sound radiated from a source in different directions.
For example, a motor vehicle sounds louder from near the exhaust than from the side of the
car.
If the source is a point source hanging in free space, the sound wave will propagate in a
spherical manner, distributing its sound energy over the area of the sphere. If the source is
located near the ground, the same amount of sound energy will be distributed over a
hemispherical surface. Therefore, the sound energy will be twice that measured with
spherical propagation. This results in a general effect of reducing the measured sound
pressure level by 6 dB for each time the distance from the source doubles.
A line source such as a road will radiate sound into a half-cylindrical shape. This has the
effect of reducing the sound pressure level by 3 dB for each time the distance from the
source doubles.
Other factors influence sound propagation, such as atmospheric absorption, ground
absorption, barrier attenuation, air movement and temperature inversions. The above is by
no means intended to be an exhaustive explanation of environmental noise propagation, but
should give the non-specialist reader some insight into the general principles involved.
15.2.1.3 Effects on the Human Population
The most recent collation of the potential effects of noise on human health and well being in
Australia was by Corbett et al (2004). A summary of the strength of evidence of
environmental noise effects on human health is reproduced in Table 15-4. The potential for
adverse health effects is not particularly helpful, however, without quantifiable data to
ascertain whether or not there will be an effect, and if there is, how significant the effect will
be. Table 15-5 provides noise levels in relevant descriptors below which health effects
would not be expected. The noise levels in Table 15-5 represent upper limits that should not
be exceeded for health reasons, however acoustic amenity is also a major consideration,
and is discussed further in Section 15.2.1.5. It is common practice in Australia to compare a
proposed introduced noise source by some comparison to the existing ambient acoustic
environment.
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15-7
Table 15-4 Strength of Evidence of Effects of Environmental Noise on Human Health
Health Outcome
PasschierVermeer, 1993
Annoyance
+
Hearing loss
+
School performance
Institute for
Environmental
Health (IEH), 1997
Health Council of
the Netherlands
(HCN), 1999
+
+
+
+
Ischaemic heart disease
+
+
+
Hypertension
+
+-
+
Sleep
Sleep pattern
+
Awakening
+
+
+
Subjective sleep quality
+
+
+
Mood next day
+
+
+
Performance next day
+
+-
+-
+
+-
+-
Psychiatric disorder
Psychiatric wellbeing
+-
Birth weight
-
Immune effects
+
+-
++-
Source: Corbett et al (2004)
Notes:
+
effect observed, Passchier-Verneer: sufficient evidence for causal association, IEH; sufficient evidence,
HCN.
+possibly an effect , Passchier-Verneer: inconclusive evidence, IEH: limited evidence, HCN.
no effect, Passchier-Verneer: not used IEH; inadequate, inconclusive evidence, HCN.
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Table 15-5 Summary of Recent Reviews on Noise Levels Below which Health Effects
would not be Expected
Health Outcome
WHO 1999
Passchoer-Vermeer
Measure
Value
In /
Outdoors
Measure
Value
In /
Outdoors
Annoyance
dBLAeq16hr
dBLAeq16hr
50-55
35
Out
In
Ldn
42
Out
Hearing loss 1
dBLAeq16hr 2 70
In
LAeq24h
70
In
School performance
dBLAeq16hr
dBLAeq16hr
Out
In
Ischaemic heart disease
LAeq06-22h
65-70
Out
Hypertension
LAeq06-24h
70
Out
SEL
55
In
Subjective sleep quality
LAeqnight
40
Out
Mood next day
LAeqnight
60
Out
Performance next day
LAeqnight
60
Out
Sleep
50-55
35
dBLAeq16hr
dBLAeq16hr
30
45
dBA
45
In
Out
Sleep pattern
Awakening
Source: Corbett et al (2004)
Notes:
1
Noise levels below which hearing impairment would not be expected:
Industrial, commercial shopping and traffic areas (in and outdoors) dB LAeq24hr 70
Ceremonies, festivals and entertainment events (<5 times per year) dBLA eq4hr 100
Public addresses (in and outdoors) dBLAeq1hr 85
Music and other sounds through headphones and earphones dBLA eq1hr 85
2
The 16hr period in the rows above refers to the period 0600 to 2200 hours
15.2.1.4 Effects on Fauna
There is limited specific data on the effects of noise on fauna. The spectral frequency
content of noise which can be heard by fauna is often assumed to be similar to sounds that
the animal produces. This is by no means a rule, e.g. dogs vocalise and can hear sounds in
the human range of perceptible frequencies, however it is known that they can also hear
frequencies that are ultrasonic to humans. Spectral power density data for fauna sounds,
however, also appear to be scarce in the literature.
Parris (2005) is presently conducting research into the effects of urban noise on bird calls,
which emulates research conducted in Europe. The European research indicated that birds
may increase the strength of their calls to overcome ambient noise. Brumm (2002) reports
an increase of up to 10 dB in Nightingale song (75 dB – 85 dB) in the presence of white
noise. Birds may also increase the frequency content (pitch) of their calls to overcome the
masking effects of urban noise at lower frequencies (Parris 2005).
It is reasonable to assume that a similar effect could be expected in the vocalisations of birds
identified in The Spit area, although attempting to quantify the effect claiming any degree of
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15-9
certainty would be fraught with potential error. At best, the observed sound pressure level
produced by birds in the area can be used to guide the level of background noise that can be
tolerated without adverse interference. An unidentified bird at Doug Jennings Park produced
a sound pressure level of 60dB LAMax at a distance of approximately 30 m. This equates to a
sound power level of approximately 100dB LAMax.
15.2.1.5 Criteria
In line with Queensland Environmental Protection Agency (Qld EPA) policy, noise from
continuous sources should be limited to 3 dB above the background noise level, unless the
combined noise level would exceed the recommended background noise level for the
receiver zone. In that case, the noise level from the source is set so that the combined
introduced source and ambient noise level for the receiver zone does not exceed its
maximum level. The derivation of the LA90(1 hour) and LAeq(1 hour) noise criteria with
consideration to the Planning for Noise Control guideline are provided in Table 15-6 and
Table 15-7. It can be seen that compliance with the Qld EPA criteria will automatically
comply with the WHO criteria in Table 15-5.
Table 15-6 Derivation of Noise Impact Level Criteria for Continuous Sources
Day
Evening
Night
Rating Background Level
47
44
41
Recommended minLA90 (PNC Table 1)
45
30
35
minLA90 Adjusted = RBL – 10 (PNC Table 2)
37
34
31
Table 15-7 Derivation of Noise Impact Level Criteria for Intermittent Sources
Day
Evening
Night
Measured Planning Noise Level (PNL)
60
56
53
Specific Noise Level (RBL + 3dB)
40
37
34
Recommended Maximum PNL (PNC Table 3)
60
55
50
PNL Modified = PNL Measured – 10dB (PNC Table 4)
50
46
43
LAeq (1 hour) criterion
40
37
34
Maximum noise levels at night time should be restricted to prevent sleep disturbance. The
WHO (1999) recommends a maximum noise level of 45 dB LAmax to achieve this. Current
QLD EPA policy is to limit the external maximum noise impact level according to the number
of occurrences likely to occur and the potential noise reduction from outside – inside. A “mid
range”external noise level of 55dB LAMax is considered appropriate for assessment
purposes, as a 10dB outside – inside reduction in noise level through a partially open
window is typical.
Planning levels for road traffic noise are established in Queensland legislation. The
maximum road traffic noise level impacting on a sensitive receiver from a public road that is
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not a State controlled road is 63dB LA10(18 hour), measured at 1m from the façade. Sensitive
receivers include permanent residences, schools, hospitals and child care centres.
Construction noise impacts are regulated by time of day only in Queensland, with good
management practices preferred which minimise noise impacts as far as practicable.
15.2.1.6 Operational Noise Impact Levels
Potential noise sources associated with the Project that have been identified are:
»
Ship engine noise entering/leaving port;
»
Ship horn entering/leaving port;
»
Ship generator noise while in port;
»
Mechanical plant noise associated with buildings at the new marina;
»
Increased vessel traffic on the Broadwater; and
»
Increased road traffic on Sea World Drive.
The first two sources noted are not considered to be particularly significant due to their
intermittent frequency and relatively short duration. However, at night-time these sources
may cause sleep disturbance.
Ship generator noise and mechanical plant associated with the proposed marina are
assumed to be continuous. The noise impact from these sources at residences on the
western side of the Broadwater was modelled using Cadna. A noise contour drawing of
continuous A-weighted sound pressure levels for ground level and high-rise residential is
shown in Figure 15-2 and Figure 15-3.
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Figure 15-2 CadnaA Modelled Continuous Noise Source Contours 2m
Note:
-5
Results are ‘
A’frequency weighted decibels re 2x10 Pa
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Figure 15-3 CadnaA Modelled Continuous Noise Source Contours 50m
Note:
-5
Results are ‘
A’frequency weighted decibels re 2x10 Pa
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The sound power level for the cruise ship stack was estimated using procedures from Bies
and Hansen (2002), assuming a 2 MW generator would be required for the ship while in port,
with a suitable muffler system. The estimated sound power level of the vertical stack is
provided below in Table 15-8. Directivity indices for the 1/1 octave band centre frequencies
were applied by the Cadna model.
Table 15-8 Estimated Sound Power Level for a Cruise Ship Stack in Port
1/1 Octave band centre frequency (Hz)
31.5
63
125
250
500
1000
2000
4000
8000
Total
SWL 2MW diesel
engine at end of 40m
pipe (dB re 10-12W)
115
111
117
113
105
101
95
85
77
120
SWL (A-weighted
dB re 10-12W)
75
84
101
104
101
101
96
86
76
108
Reactive muffler
insertion loss (dB)
15
20
25
23
21
20
19
18
18
30
SWL (A-weighted dB re
10-12W) termination to
atmosphere
60
64
76
81
80
81
77
68
58
87
Source: Bies and Hanson (2002)
Sound power levels for the mechanical plant units was estimated to be 90dB(A) per unit.
The continuous noise level produced while a ship is at the terminal was predicted using the
CadnaA model. Contour plots of noise levels at 2 m above ground level and 50 m above
ground level (corresponding with multi-storey apartments on the western side of the
Broadwater) are shown in Appendix F. Noise impact levels at the western side of the
Broadwater do not exceed 30dB LAeq, thereby complying with the criteria in Table 15-6.
Intermittent noise sources from activities associated with thecruise ship terminal and marina
are assessed using the LAeq(1 hour) criteria from Table 15-6.
These activities include loading/unloading, passenger vehicles attending the site, etc. Sound
power levels of typical noise sources potentially associated with the terminal and marina
were sourced from GHD’
s internal database, and their estimated noise impact levels at
various distances are shown in Table 15-9.
Table 15-9 Noise Impact Levels from Ancillary Activities to the Terminal and Marina
Plant Activity SWL dB(A)
20m
50m
100m
1000m
1400m
Impact noises from loading/unloading 105
71
63
57
37
34
Refrigeration plant on vehicles 85
51
43
37
17
14
Car engines 90
56
48
42
22
19
Car door closures 98
64
56
50
30
27
It can be seen that residences on the western edge of the Broadwater will not be exposed to
noise levels that exceed the criteria for day, evening or night time. Moreover, activities
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associated with the cruise ship terminal and marina are generally not expected to be audible
at those residences above the present level of background noise.
Doug Jennings Park, the kiosk, and the jetty are all currently exposed to significant vehicular
and associated noises, as well as noise from the larger sand pump station. The above noise
sources not currently endemic to The Spit area can be controlled through detailed design
measures. Operational noise sources from the facility are comparable to existing measured
noise levels, and are therefore not expected to have an effect on avifauna in the area.
An estimate of the increase in road traffic noise from Sea World Drive requires traffic
volumes with, and in the absence of, the proposal. Traffic volume estimates based on a
2002 Gold Coast City Council report (Harrison. 2002) are shown below in Table 15-10. The
figures shown include traffic from a proposed Wavebreak Island link not included in this
assessment.
Table 15-10 Traffic Volumes on Sea World Drive
Section of Sea World Drive
2011 Traffic Volume
without proposal
2011 Traffic Volume
with proposal
Macarthur Pde – Sea World entrance
16,500 – 28,300
16,500 – 28,300
Sea World entrance – public boating facilities
8,000 – 17,000
19,800 – 28,300
Public boating facilities to nth. end of spit (1.2km).
8,000 – 17,000
12,300 – 12,700
Source: Gold Coast City Council Estimates
Predicted traffic volumes and additional traffic due to the proposal, as described in Section 0
are shown in Table 15-11.
Table 15-11 Traffic Impact by Road Segments
Road Segments
Background AADT
(2006)
Estimated Development
Traffic Volume (vpd)
% Impact
Sea World Drive
21514
2416
11.2 %
Macarthur Parade
15146
798
5.3 %
Waterways Drive
24409
1608
6.6 %
Estimated increases in road traffic noise for each road in Table 15-11 above are provided
below in Table 15-12, using the formula in Section 15.2.1.1.
Table 15-12 Potential Increases in Road Traffic Noise by Road Segment
Road Segments
Background
AADT (2006)
Estimated
Development Traffic
Volume (vpd)
Estimated Increase in Road
Traffic Noise Levels (dB re
2x10-5Pa)
Sea World Drive
21514
2416
0.5
Macarthur Parade
15146
798
0.2
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Road Segments
Background
AADT (2006)
Estimated
Development Traffic
Volume (vpd)
Estimated Increase in Road
Traffic Noise Levels (dB re
2x10-5Pa)
Waterways Drive
24409
1608
0.3
The increases in road traffic noise shown above indicate minimal increases in road traffic
noise as a result of the development. Moreover, as background traffic volumes and
subsequent noise increases, additional noise from the proposal will become even less
significant.
15.2.1.7 Construction Noise Impacts
Typical noise levels produced by construction plant anticipated to be used on site were
sourced from AS 2436 – 1981 Guide to Noise Control on Construction, Maintenance and
Demolition Sites and from GHD’
s internal database. Propagation calculations take into
account sound intensity losses due to spherical spreading, with additional minor losses such
as atmospheric absorption, directivity and ground absorption ignored. As a result, predicted
received noise levels are expected to be slightly conservative.
Received noise produced by anticipated activities, during the construction of the upgraded
facility is shown in Table 15-13 for a variety of distances to a typical receiver, with no noise
barriers or acoustic shielding in place and with each plant item operating at full power. The
sound power levels shown in Table 15-13 are maximum levels produced when machinery is
operated under full load.
Table 15-13 Predicted Plant Item Noise Levels, dB(A) re 20 µPa
Distance
Plant Activity
SWL dB(A)
40 m
80 m
160 m
320 m
640 m
1400 m
Crane 110
70
64
58
52
46
39
Backhoe 108
68
62
56
50
44
37
Compressor 100
60
54
48
42
36
29
Concrete Pump 109
69
63
57
41
35
38
Dump Truck 108
68
62
56
50
44
37
Water Tanker 109
69
63
57
51
45
38
Compactor 110
70
64
58
52
46
39
Concrete Saw 118
78
72
66
60
54
47
Paver 113
73
67
61
55
49
42
Rock Breaker 118
78
72
66
60
54
47
Piling Impact Boring 120
80
74
68
62
56
49
15.2.2
Underwater Noise
Sound in the ocean as a physical phenomenon is well understood, with many military and
survey applications used world-wide. Sound intensity underwater is described differently to
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sound in air due to different physical properties of the medium, and different reference
pressure as follows:
»
The specific acoustic impedance of water differs to that of air due to different medium
density and different acoustic velocity;
»
The reference pressure for describing sound pressure levels in air is 2x10-5 Pa, while
underwater the reference pressure used is 1 x 10-6 Pa.
The combined effect of these differences is that a sound pressure level in air can be
approximately related to the sound pressure level underwater by the relationship:
SPLAir = SPLWater – 62dB
The 62dB difference consists of 26dB for the differences in reference pressure, and 36dB for
the differences in specific acoustic impedance (medium density and acoustic velocity).
15.2.2.1 Propagation
Sound travels away from a source underwater according to the same general theory of
geometric spreading as sound in air. The “shape”in which the sound intensity propagates
away from the source underwater can, however, differ from that typically used in air,
depending on the location of the receiver with respect to the source. In air, a “point”source
close to the ground compared to an observation point will radiate into the atmosphere in a
hemispherical pattern if unobstructed, resulting in the familiar “inverse square”relationship of
sound intensity and distance from the source i.e. the sound intensity will decrease by 6 dB
for each doubling of distance. An underwater sound source near the surface (or bottom) of
the ocean will also exhibit this relationship as long as the receiver is at a distance that is less
than or equal to the depth of the water column in that location. Beyond this point, the sound
will, for practical purposes, be contained between the surface of the ocean and the seabed,
and the “shape”of the acoustic wave front will be distorted with distance until far away from
the source it resembles a cylinder, for which the sound will decay by approximately 3 dB for
each doubling of distance.
Different frequencies are attenuated in water over distance in varying degrees as in air. The
noise sources considered for this assessment will be of frequencies low enough that this
effect will be negligible at the source – receiver distances considered.
15.2.2.2 Effects on Humans
Information in the literature regarding the effects of ambient underwater noise levels on
humans appears to be limited to occupational health issues. This is expected for the
following reasons:
»
The number of people exposed to noise whilst diving recreationally is negligible in terms
of a total population percentage;
»
Safety concerns are expected to implicitly result in selection of recreational dive sites that
are well separated from large noise sources such as large vessels and underwater
machinery; and
»
The exposure time of recreational divers to ambient underwater noise is limited by the
dive time, usually in the order of 1 – 2 hours.
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Occupational Health literature is available which addresses commercial diving, however the
sound intensities experienced by commercial divers that are often less than 1 m from the
source are significantly greater than those experienced by a recreational diver hundreds of
metres from the source.
15.2.2.3 Effects on Cetaceans
Underwater noise and its specific impact on marine life is not well understood, with reliable
data collection involving controlled experiments with marine creatures proving very difficult.
Extreme events involving high powered sonar have been documented, however that is not
relevant to this project.
There is a significant volume of literature, however, which documents observations of
cetacean behaviour in the presence of marine vessels. The behaviour has been observed at
distances too great for visual cues to be possible, therefore it must be considered that noise
is a primary source of stimulation in the studies.
An overview of the present knowledge of underwater noise and its effects on cetaceans is
provided by Simmonds, Dolman and Weilgart (2003). The animals of most concern to this
assessment are those reported to inhabit, or migrate through the area, being humpback
whales and bottlenose dolphins.
The most relevant study of this topic relating to humpback whales is by Van Parijs and
Corkeron (2001), who conducted observations of humpback whales (Sousa chinensis) in
Moreton Bay. Their findings are summarized below:
»
The rate of Pacific humpback dolphin, Sousa chinensis, whistling significantly increased
when boats entered an area.
»
Click train or burst pulse rates were not affected.
»
Whistling rates increased when boats came within 1.5 km of the dolphins.
»
Groups with no calves produced significantly fewer whistles.
»
It was suggested that mother-calf pairs were most disturbed by transiting boat traffic.
Studies of bottlenose dolphin behaviour in the presence of vessels in Australia have been
conducted by Crosti and Arcangeli (2001) (Perth) and Scarpaci et al (2000) (Port Phillip
Bay). Their findings are summarised below:
Crosti and Arcangeli »
Decrease in dolphin feeding and resting behaviour was correlated with the presence of
dolphin watching boats (p<0.01 and p<0.05 respectively). In addition, travelling behaviour
increased with presence of tour boats (p<0.01).
»
In the presence of boats, duration of behaviours decreased (p<0.01 feeding & resting,
p<0.05 socialising).
»
Mean group size increased with the presence of tour boats (p<0.01)
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Scarpac »
Whistle production by bottlenose dolphins was significantly greater in the presence of
commercial dolphin swim-tour boats. The behaviour exhibited by the dolphins prior to the
arrival of the boats did not affect this increased rate of vocalisations.
15.2.2.4 Effects on Fish
Audiometry data are available for a number of fish species. However, again, a level of
disturbance relating to a noise level is unknown.
15.2.2.5 Methodology
The methodology adopted for estimating the underwater noise impacts of the proposal have
been adapted from Hazelwood and Connelly (2005). The general methodology is the same
as that for assessing environmental noise in the terrestrial environment, as follows:
»
Estimate the sound power of the vessels / equipment to be used;
»
Estimate the sound propagation; and
»
Estimate the likely background sound levels.
»
Relate the sensitivity of the receptors to the background and additional sounds.
The acoustic “leakage”of marine vessels has been reported to be in the order of a few parts
per million of the engine power (Urick 1983) for a well-maintained vessel. Data presented by
Hazelwood and Connelly (2005) indicate that at low engine speed, the sound power is
reduced by approximately 10dB, or 1/10th the “rated”sound power. The style of cruise liners
expected to utilise the facility have total power outputs in the order of 40,000 – 50,000 kW for
the main propulsion system, and up to 11,000 kW for the bow and stern thrusters combined
(Knaggs 2000). Estimates of sound power levels produced by these sources based on an
“acoustic efficiency”of 5 ppm (0.5 ppm for main engines coming into port) are provided
below in Table 15-14.
Table 15-14 Underwater Sound Power Level Estimates
Source
Sound Power Level (Watts)
Main Engines
Bow/Stern Thrusters
Sound Pressure Level @ 1m
(dB re 1µPa)
0.02 – 0.025
157 – 158
0.055
151
Radiated noise was calculated for:
1. Bow/stern thrusters operating at the marina; and
2. Cruise ship main engine noise levels at various distances from the ship.
Terrestrial noise impact assessments generally examine the overall exposure to a noise in
conjunction with, or as a priority to, maximum noise levels. In this case, the increase in the
vessel traffic that would be expected to use the seaway with the proposed marina compared
to the vessel traffic that currently use the seaway is an indicator of the increase in noise
exposure. Assuming the average underwater noise emissions from vessels with the
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proposal is the same as existing vessels, the increase in noise level can be estimated with
the following relationship:
Increase in LAeq Noise Level = 10 x log10(No. of vesselsFuture/No of vesselsPresent)
15.2.2.6 Criteria
Establishing noise criteria for fauna, particularly in a submarine environment, is a difficult
task based on information in the present literature. The approach, therefore, is to compare
expected noise impacts with existing noise levels.
The seaway is currently used in diving promotions advertising the abundance of marine
fauna that can be observed in the area. This includes the “sand pipe”, which traverses the
seaway channel and therefore has all seaway marine traffic passing overhead. This
indicates that present levels of vessel traffic in the seaway are tolerated by the marine fauna
present.
Existing underwater noise levels can be estimated from published data (Sidmonds et al.
2003), as shown in Table 15-15. The sound pressure level at 1 m is the published source
data. The calculated sound pressure levels at 4 m, 8 m and 15 m represent the expected
noise level at different depths in the seaway (MSQ 2005). The operating conditions for the
vessels listed in Table 15-15 are at high power, which is consistent with observations of
vessels in the seaway.
Table 15-15 Estimated Existing Underwater Noise Levels in the Seaway
SPL @ 1m
dB re 1µPa
Vessel
SPL @ 4m
dB re 1µPa
SPL @ 8m
dB re 1µPa
SPL @ 15m
dB re 1µPa
650cc Jetski
125
113
107
101
7m outboard motor boat
156
144
138
132
Fishing boat
151
139
133
127
Fishing trawler
158
146
140
134
The above calculated noise levels from existing vessels that use the seaway indicate
maximum underwater noise levels experienced are in the range of 100 – 150 dB re 1µPa.
This range will be used to assess the potential impacts from the proposed facilities.
15.2.2.7 Noise Impact Levels
Underwater noise levels from proposed cruise ship visits were calculated according to the
methodology in Section 15.2.2.5, and are shown below in Table 15-16. The noise impact
level for the bow/stern thrusters was calculated with a directivity factor of 4 to account for the
source proximity to the rock wall.
Table 15-16 Underwater Sound Power Level Estimates
Source
Main Engines
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SPL @ 15m
dB re 1µPa
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dB re 1µPa
130
SPL @ 600m
dB re 1µPa
118
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Bow/Stern Thrusters
131
126
115
Table 15-16 indicate that even at a range of 15 m, the noise impact levels from the cruise
ship are comparable to those expected from vessels that currently utilise the seaway.
The increase in seaway traffic can be estimated from the number of marina berths proposed,
and the number of vessels that currently have access to the seaway. From aerial
photographs, it appears that the number of moorings on waterways that connect to the
seaway is in the order 2,000 – 3,000. It would be unreasonable to expect that the number of
berths with access to the Seaway is representative of the number of vessels that frequent its
passage, however the same could be said for boats moored at the marina, and an
assumption of proportions is used. The proposed number of berths at the marina is 345,
plus 22 berths for commercial vessels. The increase in the long-term underwater LAeq noise
level is therefore not expected to be any greater than 1 dB as a result of the new marina.
15.2.3
Potential Vibration Impacts
15.2.3.1 Overview
Vibration travels through the ground primarily by surface (Rayleigh) waves, and secondarily
by body (compression and shear) waves (Amick and Gendreau. 2000). Vibration as an
environmental metric is generally represented as acceleration or peak particle velocity. The
potential impacts being assessed determine which metric is used e.g. human comfort is
usually assessed using acceleration, while peak particle velocity is used to assess potential
damage to buildings.
Impulsive forces on the ground produce vibration levels depending on the magnitude of the
force. As the vibration moves away from the source, it is reduced in amplitude by geometric
spreading, and dissipation of energy within the ground. The latter is a function of the ground
material e.g. rock, sand, clay etc.
15.2.3.2 Criteria
The New South Wales Department of Environment and Conservation publication Assessing
Vibration: a technical guideline (2006) provides human amenity criteria for vibration at
sensitive receivers. The guidelines are provided in Table 15-17.
Table 15-17 Preferred and Maximum Weighted rms Values for Continuous and
Impulsive Vibration Acceleration (m/s2) 1–80 Hz
Location
Preferred Values
Maximum Values
z-axis
x- y-axes
z-axis
x- y-axes
Day or night
0.0050
0.0036
0.010
0.0072
Residences
Day
Night
0.010
0.007
0.0071
0.005
0.020
0.014
0.014
0.010
Offices, schools etc
Day or night
0.020
0.014
0.040
0.028
Assessment
1
Period
Continuous vibration
Critical areas
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Location
Assessment
Period 1
Preferred Values
Maximum Values
Workshops
Day or night
0.04
0.029
0.080
0.058
Critical areas
Day or night
0.0050
0.0036
0.010
0.0072
Residences
Day
Night
0.30
0.10
0.21
0.071
0.60
0.20
0.42
0.14
Offices, schools etc
Day or night
0.64
0.46
1.28
0.92
Workshops
Day or night
0.64
0.46
1.28
0.92
Impulsive vibration
Source: Department of Environment and Conservation 2006
Notes:
1
Day time is 7.00 am to 10.00 pm and night time is 10.00 pm to 7.00 am
2
Eg: hospital operating theatres and precision laboratories where sensitive operations are occurring.
The NSW EC document also provides conversion values so that the above units can be
expressed in, for example, mm/s. The criteria for residences at night time equates to a peak
particle velocity of 2 mm/s.
Vibration levels considered necessary to achieve damage in buildings considerably higher
than the threshold of human perception. Typical vibration criteria addressing damage in
buildings is greater than 10 mm/s (Amick and Gendreau 2000), even for residential buildings
in poor condition, compared to a human perception “troublesome”level of 5 mm/s (Siskind
1981).
15.2.3.3 Construction Vibration Impact
The major concern for vibration impacts will be if driven piles are used to construct the cruise
terminal and/or marina. Human comfort is a consideration for the kiosk, with damage criteria
applicable to the kiosk building, jetty, seaway tower and pump station buildings.
Table 15-18 shows the distances from each of the identified receivers on the spit to the
proposed cruise terminal location.
Table 15-18 Distances from Potential Pile-driving Locations to Nearby Structures
Site
Distance from marina (m)
Distance from terminal (m)
Sand pump station (jetty)
400
290
Sand pump station (marine
stadium)
50
370
Nara resort
480
1660
Sea-world
650
1800
Seaway tower
200
570
Sand pipe (submarine)
530
118
Kiosk
390
200
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The shortest distance from a pile driving activity to a structure is from the nearest proposed
marina wharf to the sand pumping station at the marine stadium (50m). The expected
vibration level at this distance is approximately 2 mm/s (Amick and Gendreau 2000) (see
Appendix F).
Pile driving at the proposed terminal location is expected to produce vibration levels of
approximately 0.5 mm/s. This level is significantly below the 2 mm/s criterion for a residence
during the night.
Construction traffic will include heavy vehicles, however there are no significant earthworks
associated with the project which would require high traffic volumes, and potential impacts
will be very transient.
It is not foreseen that blasting would be required for any part of the project.
15.2.3.4 Operational Vibration Impact
There are no significant operational vibration sources associated with the proposal.
15.3
Recommended Mitigation Measures
15.3.1
Operational Airborne Noise
The location of the proposal is at significant distances from nearby sensitive receivers, which
provides a high level of noise attenuation due to geometric spreading. Specific mitigation
measures that would be required for the proposal to be acceptable in the existing acoustic
environment are:
»
Verification from ship operators of the noise emissions from ships in port;
»
Limit port entry/egress to daytime/early evening due to fog horn warnings and engine
noise;
»
Detailed design of loading/unloading area to prevent nuisance noise travelling across the
Broadwater to residences, and to maintain a level of amenity in Doug Jennings Park; and
»
Check of proposed mechanical plant at detailed design stage to ensure background
creep is avoided.
15.3.2
Operational Underwater Noise
There is limited scope for mitigating underwater noise. The assessment in Section 15.2.2.7
shows that adverse impact from the proposal is unlikely, due mainly to the expected existing
underwater noise levels in the Seaway and Broadwater.
15.3.3
Construction Noise
To minimise noise emissions during construction, the following management and mitigation
measures are available to ameliorate likely noise impacts:
»
All combustion engine plant, such as generators, compressors and welders will be
checked to ensure they produce minimal noise with particular attention to residential
grade exhaust silencers;
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»
Vehicles will be kept properly serviced and fitted with appropriate mufflers. The use of
exhaust brakes will be eliminated, where practicable;
»
Where practical, all vehicular movements to and from the construction site must be made
only during normal working hours;
»
Where practical, machines will be operated at low speed or power and will be switched
off when not being used rather than left idling for prolonged periods;
»
Machines found to produce excessive noise compared to industry best practice will be
removed from the site or stood down until repairs or modifications can be made; and
»
Where practical, impact wrenches will be used sparingly with hand tools or quiet
hydraulic torque units preferred.
With regard to potential traffic noise, by keeping plant related vehicles serviced, fitted with
mufflers and eliminating exhaust brake usage, noise due to trucking activity associated with
the operation and construction of the terminal and marina can be significantly mitigated.
15.3.4
Construction Vibration
Bored piles may be used rather than driven piles, however other environmental impacts
associated with this method in the water body (sediment suspension) may not be
acceptable. In any case, sheet piles (driven by a vibratory pile driver) will still possibly be
used.
It is recommended that, if the project is constructed, a construction management plan
addressing vibration includes the following:
»
Condition surveys of nearby buildings including the Seaway tower, kiosk and sand pump
buildings, and the jetty be conducted prior to any pile driving, and if the project is to
include road upgrading and consequent use of vibratory rollers;
»
On site vibration measurements are conducted at the initiation of pile driving at the kiosk
building to check the validity of vibration level predictions, and
»
Regularly check the condition of Sea World Drive to ensure that any heavy vehicles
frequenting the site are not hitting pot-holes and causing unnecessary vibration to
adjacent structures.
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