1/355 Manukau Road Epsom, Auckland 1023 PO Box 26283 Epsom, Auckland 1344 T: 09 638 8414 E: [email protected]
WAITOMO SKY GARDEN
PUKEROA ROAD, HANGATIKI
ASSESSMENT OF NOISE EFFECTS
Report No 17285
Prepared for: Prepared by: …………………….
Waitomo Sky Garden Ltd Nevil Hegley Hamilton 9 July 2019
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CONTENTS
1 INTRODUCTION ............................................................................. 3
2 DESIGN CRITERIA ......................................................................... 4
3 PROPOSAL ................................................................................... 7
4 PREDICTED NOISE ...................................................................... 13
5 CONCLUSIONS ............................................................................ 18
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1. INTRODUCTION
Waitomo Bungy Ltd is proposing to develop a bungy tower approximately 68.5m high
and associated tourist activities at Pukeroa Road located approximately 400m to the
west of the State Highway 3 and State Highway 37 roundabout as show on Figure 1.
This report assesses the noise that will be heard in the surrounding area from people
bungy jumping and associated tourist activities.
Figure 1. Location of proposed bungy site
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2. DESIGN CRITERIA
The site and surrounding sites are located in a Rural Zone in the Waitomo District
Plan. The relevant section of Rule 20.5.1, Conditions for Permitted Activities
(excluding Temporary Military Training Activities covered by Rule 20.5.3) are:
All permitted activities shall be carried out such that the noise level at the boundary of the site that the noise generating activity is located on (or notional boundary in the Rural Zone – see definition in Section 28) in the relevant zone as set out in the following table is not exceeded.
Zone Maximum Noise (dBA) Day time L10 Night time L10
Residential 55 40 Rural 50 40 Conservation 50 40
Rule 20.5.1.1 states:
(a) Daytime means 7.00am to 10.00pm Monday to Saturday and 8.00am to 5.00pm Sundays and Public Holidays.
(b) Night-time means all other times. (c) In any zone no single event noise shall exceed 70dBA Lmax at night time.
Rule 20.5.1.4 States:
All noise levels shall be measured and assessed in accordance with the requirements of NZS 6801:1991 The Measurement of Sound and NZS 6802:1991 Assessment of Environmental Sound. The noise shall be measured with a sound level meter complying with the International Standard IEC65I (1979): Sound Level Meters, Type 1.
Noise associated with the proposed activities is a series of single short duration
events. If the L10 measurement is to be relied on the noise will need to be present for
at least 10% of the measurement period. That is, the noise will need to be present
for a minimum of 1.5 minutes in any 15 minute period otherwise the L10 level will not
include noise from activities such as bungy jumping and the ziplining. Based on field
measurements it will be unlikely if the noise from people jumping and any support
friends will influence the L10 level. To overcome this problem it is proposed to take on
the LAeq measurement as adopted in NZS 6802:2008 Acoustics - Environmental
Noise. Thus, the recommended design criteria are:
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All activities shall be carried out such that the noise level at the boundary of the site that the noise generating activity is located on (or notional boundary in the Rural Zone) does not exceeded:
Zone Maximum Noise (dB)
Day time LAeq Night time LAeq Rural 50 40
The noise shall be measured in accordance with the requirements of NZS6801:2008 Acoustics - Measurement of Environmental Sound and assessed in accordance with the requirements of NZS6802:2008 Acoustics – Environmental Noise
Rule 20.5.1.5 states:
All construction shall be carried out so as to comply with New Zealand Standard NZS 6803P:1984.
The 1984 Construction Standard has been updated with NZS6803:1999 Acoustics –
Construction Noise (NZS603) and it is recommended this later Standard be used as it
removes the ambiguities in the 1984 version. The only other significant difference
between the two Standards is the L10 has been replaced with Leq. In general, if the
1999 version of NZS6803 is compiled with then the 1984 version will also be
complied with.
The recommended construction noise levels set out in Table 2 of NZS6803 are:
Table 2 - Recommended Upper Limits for Construction Noise Received in Residential Zones and Dwellings in Rural Areas
Time of week Time periodTypical duration
(dBA) Short term duration
Long term duration
Leq Lmax Leq Lmax Leq Lmax Weekdays 0630-0730 60 75 65 80 55 75
0730-1800 75 90 80 95 70 85 1800-2000 70 85 75 90 65 80 2000-0630 45 75 45 75 45 75
Saturdays 0630-0730 45 75 45 75 45 75 0730-1800 75 90 80 95 70 85 1800-2000 45 75 45 75 45 75 2000-0630 45 75 45 75 45 75
Sundays and public holidays
0630-0730 45 75 45 75 45 75 0730-1800 55 80 55 85 55 85 1800-2000 45 75 45 75 45 75 2000-0630 45 75 45 75 45 75
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Where: (a) "Short-term" means construction work at any one location for up to 14
calendar days; (b) "Typical duration" means construction work at any one location for
more than 14 calendar days but less than 20 weeks; and
(c) "Long-term" means construction work at any one location with a duration exceeding 20 weeks.
It is expected the total construction period will be longer than 20 weeks so the long
term duration noise levels, as set out in Table 2 will be applicable for the duration of
the construction works.
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3. PROPOSAL
Waitomo Sky Garden activities will include:
Facility Building Located near the tower and will contain the entry/exit, souvenir shop, café, toilet/change room area, management offices, photo/video suite, workshop for maintenance and bungy cord construction, viewing area from deck/outdoor area, rubbish collection. The facilities building will open to the public from 8am until 10pm;
Tower Activities The proposed bungy will be approximately 55m in length and will
operate from the proposed tower.
The proposed slide runs from the top of the tower to the bottom of the tower.
The proposed swing will be approximately 40m in length and will operate from the proposed tower. The proposed zipline will be a maximum length of 945m and will be located so zip lining can occur through the trees from top of the proposed tower.
The proposed attraction will be open for business 7 days a week, including public
holidays, between the hours of 8am to 11pm for the tower and the facility building
including the proposed cafés. Staff hours will be between 6.50am and 11.10pm.
The proposed activities within the tower including the bungy, slide and viewing
platform will operate between 8am and 7pm. The zipline is proposed to be open
between 8am and 10.30pm.
The closest dwelling is approximately 230m from the bungy jumping and swing,
which are the noisier activities. This includes the activities that operate into the time
period when the lower night time noise limits come into effect. That is after 10:00pm
Monday to Saturday and 5.00pm on Sundays and Public Holidays.
The main activity likely to generate any noise beyond the site boundary will be from
the proposed 68.5m high bungy tower structure with the bungy jump platform at 55m
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as shown on Figure 3. Noise from the swing will be secondary to the bungy jump and
the zipline will be the quietest of the three facilities.
The only other noise source will be from the construction of the facility. This will
include preparing the tower platform which will receive material from the building and
carpark areas for preloading. A preliminary construction programme is to preload the
tower platform, which will take approximately two months to preload, then leave the
preloading over a five to six month period after which the following construction work
will be undertaken:
Construct foundations over a three week period;
Construct the tower in 10m sections over a five month period;
Construct platform and roof structure in the following three months; and
Complete fit-out and final finishes in the next three months.
Figure 3. Proposed Bungy Tower
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A mobile crane will be positioned between the tower and the building which will
service both areas. The crane will be stationary throughout construction and will be
utilised for constructing all elements of the tower in an insitu manner, it will also be
utilised for erecting the structure to the building area.
The main noise will be from the initial earthworks preparing the site. Although various
construction plant may be used, a noisier option has been assessed. The equipment
that has been evaluated for the construction period includes a 20t excavator,
bulldozer (D6), compactor, trucks and a tower crane to construct the bungy tower. At
the same time a bulldozer, excavator and compactor have been assumed to be
operating at each end of the car park. Although not all of this work would be
undertaken simultaneously the analysis has assumed this would be the case so
representing the worst possible scenario for construction noise.
To determine the noise levels of the construction equipment field measurements
were undertaken of the type of equipment expected to be used on site. Figure 4
shows a typical bulldozer with a sound power level of 106dBA. Figure 5 shows a
typical 20t excavator, which also has a sound power level of 106dBA.
Figure 4. Komatsu D53P Bulldozer
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Figure 6. Bomag BW212D Compactor
A dedicated compactor will be used to compact the material, such as a Bomag
BW212D as shown on Figure 6 which has a sound power level of 100dBA.
To provide a conservative (high) noise assessment it has been assumed there will be
up to 50 trucks per day (50 arrivals and 50 departures) to transport material to and
from the site and it has been assumed all of these trucks could be truck and trailer
units. Figure 7 shows a typical truck and trailer that has been assessed. This unit
Figure 5. 20 Tonne Excavator
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Figure 7. Truck and Trailer Unit
has a sound power level of 103dBA when travelling on an access road and this level
will drop to 101dBA when manoeuvring on site.
The only other major construction noise source will be from a tower crane expected
to be used to erect the bungy tower. Field measurements of a Favco STC 750 MK II
tower crane operating at 1200rpm and 2000rpm are:
Noise Level - dBA, Leq at 30m
ENGINE SPEED FRONT RIGHT SIDE BACK LEFT SIDE 1200rmp 68 69 69 67 2000rpm 69 70 70 69
Measurements were undertaken of the noise from people jumping at the existing
Taupo Bungy site. The weather throughout the measurement period was fine and
calm at both the measurement point and at the bungy platform. These conditions
were considered ideal for the measurement of sound.
With an unobstructed view of the Taupo bungy platform the noise measurements
were undertaken at approximately 350m from the jump site. This was the most
exposed location to the jumping where measurements could be undertaken with clear
line of sight between the jump site and receiver position.
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The noise generated from bungy jumping comprised of voices from the supporters of
the jumper on the platform, such as joining in with the count-down prior to the jump.
This did not occur very often, perhaps 1 in 8 jumps. There was also noise from some
of the jumpers as they jumped, such as calls of excitement. The levels in both cases
varied between measurable values above the background sound to just audible and
below the background sound. Many jumps took place without any sound at all.
It is worth noting that the measurements were undertaken without the knowledge of
those operating the platform or of those jumping. The jumps were considered typical
of the jumps normally made from the site.
The highest noise level from the Taupo bungy jump was recorded when one person
yelled loudly as they jumped. The maximum noise (Lmax) recorded was 51dBA. The
noise from other jumpers varied between 43 – 47dBA as a maximum level (Lmax).
The bungy jumping level has been adopted for the 120 rides on the Swing.
In order to predict the noise from the zipline field measurements were undertaken at
40m from the zipline operating at an existing site as shown on Figure 8.
Measurements of three separate runs showed the noise level was similar for each
run at 33dB LAeq based on three runs in a 15 minute period. It is expected there
would be 150 rides a day for the zipline with double this number modelled to provide
a factor of safety with the assessment.
Figure 8. Zipline Canopy Ride
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4. PREDICTED NOISE
The noise has been predicted from the site using the Brüel & Kjær Predictor program
version 2019.02. This is a powerful environmental noise calculation software
package that uses a digital terrain model with the ground conditions modelled using a
1m contour interval and each of the noise sources, as set out above, modelled at
their various locations on the ground. Calculations are undertaken in accordance
with the requirements of ISO 9613-1/2 Acoustics – Attenuation of Sound during
Propagation Outdoors. A mild temperature inversion has been assumed with ground
factor of 0.7 and a 5m grid size to calculate the noise contours. All calculations have
been undertaken at a height of 1.5m above ground level.
As shown on Figure 9, with all of the noisier construction activities occurring at the
same time including the tower crane at 50m high, the noise level at the most exposed
dwelling will be 56dBA Leq. At the same time the maximum level will not exceed
64dB Lmax. These levels are well within the 70dBA Leq and 85dBA Lmax as set out in
NZS6803.
Figure 10 shows the noise contours with the jumper at 40m above ground level.
Figure 11 shows the noise contours with the jumper 10m above ground level plus the
noise from the zipline, swing and onsite vehicles (based on the vehicle movements
predicted by the traffic engineer) with each activity operating at the maximum
expected use.
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Figure 9. Construction Noise (dBA Leq)
Figure 10. Noise with Jumper 40m above ground (dBA LAeq)
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The same noise level has been assumed in both cases although in practice once the
jumper has left the platform any noise would only originate from the jumper calling out
and will not include any support noise from friends on the jump platform.
As the noise contours are a smoothing of calculations made on a grid the noise has
also been calculated at 1m from the façade of the closer buildings for construction
noise and at the notional boundary of rural dwellings.
Figure 12 shows the location of the closer dwellings around the proposed bungy site.
The results of the predictions for the noise from the bungy, zipline, swing, slide and
vehicles are shown in Table 1.
Figure 11. Noise with Jumper 10m above ground (dB LAeq)
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Site Construction With bungy sound at 40m above ground
With bungy sound at 10m above ground
1 36 17 17 2 56 38 38 3 53 36 36 4 53 35 35 5 46 28 28 6 42 24 24 7 50 33 33 8 43 26 26 9 45 27 27
10 43 24 24 11 41 23 23 12 39 19 19 13 35 19 19
Table 1. Predicted Noise Level from all activities, dB LAeq
Figure 12. Location of Closer Noise Sensitive dwellings
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21
45
6 7
8
9
10
11
12
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Checking the above levels shows the noise level for construction work is well within
the requirements of NZS 6803:1999 Acoustics – Construction Noise.
Once operating, the noise from the site will be generated by the jumper calling out
during a jump and the encouragement sometimes given from supporters’ of the
bungy, slide, zipline, swing and vehicles. When taking the worst scenario (highest
noise levels) the noise at the notional zone boundary will be up to 38dB LAeq. This
level is well within the District Plan limits for a permitted activity.
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5. CONCLUSIONS
During the construction period the highest predicted noise for any resident will be
56dBA Leq, which is well within the District Plan criteria of 70dBA Leq for the daytime.
The maximum level from the construction noise will be up to 64dB Lmax, again this is
well within the 85dBA Lmax design limit.
Noise from the proposed Waitomo Sky Garden activities will be controlled by the
bungy jumping and to a slightly lesser extent, the swing. As the noise from those
jumping and their supporters’ is of a relatively short duration the L10 measurement as
adopted in the District Plan will not control the noise. It is therefore recommended
the LAeq limit is adopted as set out in the more recent Standards, NZS6801:2008
Acoustics - Measurement of Environmental Sound and NZS6802:2008 Acoustics –
Environmental Noise. Similarly, it is recommended the latest version (1999 version)
of the construction Standard be adopted.
The recommended control for the proposed development is:
i) All activities shall be carried out such that the noise level within the notional boundary of any dwelling in the Rural Zone does not exceed:
Zone Maximum Noise (dB)
Day time LAeq Night time LAeq Rural 50 40
ii) The noise shall be measured in accordance with the requirements of
NZS6801:2008 Acoustics - Measurement of Environmental Sound and assessed in accordance with the requirements of NZS6802:2008 Acoustics – Environmental Noise.
iii) Construction work shall be carried out so as to comply with the requirements of NZS 6803:1999 Acoustics – Construction Noise.
With the above controls in place the noise from the proposed Waitomo Sky Garden
development will be controlled to well within the above noise limits and as a result the
noise from the development will be less than minor in terms of the requirements of
the Resource Management Act.
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