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Site Investigations for Design of an Open Water Dive Attraction off the
Gold Coast
Jacob Restall1, Angus Jackson1, Bobbie Corbett1, Lawrence Hughes2 Russell Richards2,3, Rodger B.
Tomlinson2, and Frances Cream4
1 International Coastal Management, Gold Coast, AUSTRALIA; j.restall@coastalmanagement.com.au
2 Griffith Centre for Coastal Management, Griffith University, Gold Coast, AUSTRALIA
3Griffith Climate Change Response Program, Griffith University, Gold Coast, AUSTRALIA
4 Gold Coast City Council, Gold Coast, AUSTRALIA.
Abstract
The Gold Coast is a popular coastal holiday destination but beaches and surf are now not enough to remain
competitive in the Australian tourist market and the destination needs new and innovative attractions. There are
already high quality dive sites – natural and artificial. Studies are being undertaken to identify and investigate
opportunities to become a world class dive destination by providing a focus by sinking of a suitable ship or
construction of a purpose designed structure to grow the existing local recreational scuba dive industry.
A 12-month site monitoring program focusing on two potential offshore sites located in 30m water depth was
undertaken by International Coastal Management and Griffith Centre for Coastal Management on behalf of the
Gold Coast City Council. The objectives of the investigations were to (1) obtain site data to estimate the number
of safe ‘dive-able days’ for the two sites based on the prevailing wind, wave conditions, currents and visibility
and (2) to compare and evaluate each site for suitability as a dive site. The methodology involved surveying and
mapping of the two prospective sites, including bathymetric/hydrographic surveys, benthic characteristics, in situ
continuous current and turbidity measurements and identification of existing natural reefs. A range of
instruments were deployed and maintained at the two sites to provide a continuous dataset for a 12 month
monitoring period. This information was supplemented with coincident data of the local wind and wave
environment while, turbidity measurements were transformed into a measure of diver “visibility” using novel
techniques that were developed, implemented and verified.
The characteristics of the world’s top-ranked 100 dive sites were analysed and compared to the characteristics
of the two study sites used here. Overall, the monitoring data indicated a high proportion of safe dive-able days
for both sites and therefore both sites were suitable for creation of world class dive sites. However, the high
costs associated with preparation of a wreck(s) was found to be not cost-effective and would be unlikely to
achieve the potential for top 100 ranking. Rather, a 20m high trial structure is now being prepared as the next
stage of this process of enhancing the local dive industry with the data obtained used as the basis for innovative
eco–engineering design of a larger artificial structure.
Keywords: Gold Coast, dive attraction, turbidity, visibility, continuous monitoring
1. Introduction
The aim of the project was to investigate
opportunities to grow dive tourism on the Gold
Coast, Australia as a contribution towards
supporting sustainable tourism growth. There are a
number of natural and artificial dives sites already
located in this region, however no iconic dive wreck
or similar exists that acts as a focus to attract
visitors and encourage repeat visitation. The
existing artificial dive sites (Narrowneck reef and the
Gold Coast Seaway) are both the results of major
engineering works that did not anticipate diving and
habitat creation as major benefits.
Creation of dive sites and artificial reefs is too often
a “sink a wreck or drop a structure(s) and the fish
and divers will come” approach. This usually works
but misses the opportunities to maximise the habitat
value and / or dive experience.
The objective of these site investigations was to
carry out a comprehensive physical survey of the
conditions for two candidate sites for a 12 month
period to aid estimation of the number of safe dive-
able days for each of the candidate sites given the
prevailing wind, wave and current environment. A
secondary objective was to provide baseline data
that could inform the design and approvals of the
dive site infrastructure in accordance with the State
and Commonwealth regulations (including the sea
dumping permit process).
2. Investigations
The location of the two monitoring sites (labelled as
“North site” and “South site”) are presented in Figure
1 & Figure 2. Site monitoring of each site occurred
for a period of 12 months [1,2] and included the
following:
• Site-specific surveying and mapping including
bathymetric / hydrographical surveys, side-scan,
dive inspections to determine seabed
characteristics and undertake water clarity
surveying.
• Implementation, upkeep and data collection from
current meters and turbidity meters deployed at
the candidate dive sites.
• Assessment of prevailing wave and wind
conditions using data obtained from local wave
rider buoys and meteorological weather stations.
• Site inspections by divers to establish location of
any existing reef structures to avoid habitat loss
and impact on fishing sites.
• Estimation of ‘dive-able days’ over the monitoring
period based on wind, wave and current
conditions and expectation of achievable visibility.
• Assessment of accessibility from nearest
navigable entrance.
3. Site information
3.1. North Site
The proposed location for a northern dive site was
investigated first as it emerged as the preferred site
based on the initial public consultation and
economic feasibility studies. It is located 2.5km
east of Main Beach in 30m of water and the nearest
access is the Gold Coast Seaway (Figure 1).
Surveys from a single frequency echo sounder
bathymetric survey and side scan sonar were
undertaken to provide preliminary understanding
about the local seabed for the monitoring site and to
ensure that there were no obvious reef outcrops
that could diminish the site’s suitability as a dive
site. This surveying highlighted that some small
outcrops occurred within the 500m investigation
zone for this site.
It was determined that their small size and low relief
meant that any potential for negative environmental
impact would be minimal and that dive site
infrastructure could be located at this site.
However, further detailed sub-bottom may be
necessary depending on the final design of the dive
site infrastructure.
3.2. South Site
The southern monitoring location was located 2.5km
north east of Tugun in 30m of water and the nearest
access is the Tweed River entrance (Figure 2).
The initial side scan survey identified rocky outcrops
located in the area and the investigation area was
relocated a short distance to a location where there
were no identifiable features (i.e. rock outcrops)
within the 500m investigation zone.
Figure 1 North Site Monitoring Location
Figure 2 South Site Monitoring Location
Gold Coast Seaway
Main Beach
South
Stradbroke
Island
Palm Beach
Currumbin R
Tweed R
Tugun
South SIte
North Site
4. Monitoring
4.1. Instrumentation
The continuous monitoring program for the two
study sites took place between 2011 and 2013. The
instrumentation used at each site consisted of
(Figure 3):
• An ADCP to monitor ocean current strength
and direction, placed approximately 1m
above the seabed (Figure 4).
• An RBR Turbidity gauge located
approximately 10m above the seabed and
used to record turbidity levels.
• A thermister string to record the temperature
profile throughout the water column.
Figure 3 Cross section of installed instruments
Figure 4 Photo of ADCP [Source: Ian Banks]
4.2. Waves
Wave data was obtained from the Department of
Environment and Heritage Protection (EHP) wave
rider buoys located at the Seaway (north site) and
the Tweed River (south site) (Figure 5). Wave
records were also measured at the two study sites
using ADCPs. These values were compared against
the wave rider buoy data as a validation step for the
wave rider buoys. The wave rider records were
consistent with those recorded by the ADCPs for
both sites and therefore were assumed to be
representative of the local wave conditions.
Figure 4 Recorded wave data for the Gold Coast Seaway
and Tweed wave rider buoy.
4.3. Wind
Wind data was obtained from the Bureau of
Meteorology (BOM) weather stations located at the
Gold Coast Seaway (north site) and Coolangatta
(south site) (Figure 4).
Wind data from the Gold Coast Seaway indicated
that during 33% of the days over the monitoring
period there was least one wind speed
measurement that exceeded the 20 knot threshold.
It was noted, however, that only 7% of all the wind
speed measurements were greater than the
designated 20 knot threshold (i.e. for many days
wind exceedances were limited to a small number
of isolated peaks during the day).
For the wind data measured at the Coolangatta
meteorological station, there were few exceedances
in wind speed and this was attributed to natural
landforms affecting the recording of stronger
southerly conditions (Figure 4). As a result, the
Gold Coast Seaway wind data was utilized for both
sites.
Figure 5 Wind direction and speed for the Seaway and
Coolangatta monitoring stations
4.4. Site Accessibility
This data was compared with threshold values
(limiting factors) to determine the accessibility of
each of the two sites. Although these thresholds are
likely to be vessel and operator specific, nominal
thresholds of maximum wave height (HMAX) of 2m
and wind speed of 20 knots were selected. These
values were based on the threshold that operators
of the Ex-HMAS Brisbane and Ex-HMAS Adelaide
provided about limiting conditions for their
operations.
5. Site monitoring
5.1. Visibility – Secchi Disk readings
To correlate the continuous data from the turbidity
instruments with diver visibility, a key parameter for
safety and quality of a dive, manual Secchi disk
measurements were taken regularly during each
site visit (approximately monthly intervals). The
Secchi disk readings were taken horizontally at five
metre intervals throughout the water column. Figure
6 shows that the visibility measurement being taken
by divers with the results presented in Figure 7
(North Site) and Figure 8 (South Site).
Figure 6 Visibility Measurement using Secchi disk with
diver and Secchi disk just visible.
Figure 7 Secchi Disk Measurements North Site
Figure 8 Secchi Disk Measurements South Site
5.2. Turbidity and Visibility Correlations
The Secchi disk data collected by the divers as part
of this study was compared against the turbidity
readings to derive a site-specific relationship
between these parameters. This data was
supplemented by data obtained from existing (and
local) monitoring programs such as the
environmental health monitoring program (EHMP).
Regression analysis has been used to establish a
functional relationship between Secchi depths and
turbidity (Figure 9) that can be used to inform the
researchers about the visibility of the study sites
(Figure 10 and Figure 11) in the context of dive-ability.
Note that the data gap (February-March 2012) for
the north site (Figure 10) was a result of monitoring
equipment failure (i.e. turbidity measurements were
not available for this period).
Figure 9 Conversion of NTU to Secchi depth (visibility)
5.3. Visibility
A 2 metre safety threshold was specified for visibility
based on discussions with the dive industry. This
threshold was then used as the basis for evaluating
the conditions experienced on the site in regards to
diver safety.
Throughout the monitoring period the day-averaged
visibility (as indicated by the red lines in Figure 10
and Figure 11) did not drop below the 2m threshold
for either site. Also, the absolute minimum visibility
experienced only drops below 2m a few times
during the monitoring period. Conversely, the
visibility for both sites exceeded 10m more than
60% of the time. These results indicate that visibility
is unlikely to be a limiting condition for either site.
Figure 10 Visibility Data (north site)
Figure 11 Visibility data (south site)
5.4. Ocean Currents
The potential effects of ocean currents on dive site
safety were evaluated using the ADCP velocity
data. Current profiles were summarised by eliciting
the minimum, maximum and average currents
experienced throughout the water column (Figure 12
and Figure 13). A nominal limiting threshold of
0.5m/s (or 1 knot) was selected to determine when
it would be safe to dive.
Figure 12 Water current measured by the ADCP - (north
site)
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Figure 13 Water current measured by the ADCP - (south
site)
During the monitoring period the maximum current
throughout the water column only exceeded 0.5m/s
for 5-6% of the time, which equates to around 18 -
22 days per year.
5.5. Marine ecology
As well as physical features, observations of the
marine ecology was observed, photographed and
evaluated by a commercial diver on the team, Ian
Banks. From the photos and dive observations, the
site has the potential to attract a diverse number of
interesting pelagic and benthic species, including
turtles and dolphins.
6. Summary
Based on the observations of the dive team and an
assessment of the results of the continuous
monitoring program, the two candidate dive sites
that were investigated appear suitable for this
purpose. If designed correctly, this would create a
safe dive site with a diverse and sustainable marine
habitat and provide a world class dive.
The consideration of all the factors and limiting
thresholds indicates that:
• Around 55% of the year the site will experience
days where there is no exceedance of any of
the thresholds, which equates to around 195
diveable days per year.
• Waves are the key factor in accessibility and
dive-ability of this site. This indicates that
vessels, such as catamarans, with good
stability will provide significantly higher
diveable days per year.
7. Dive Sites Research
International Coastal Management have carried out
R&D on the creation of fish habitats and dive sites
to enable such sites to be designed to achieve
specific project objectives. The top 100 dive sites in
the world have been analysed as part of the R&D to
determine what makes a top dive site. The
attributes of the top 100 sites are:
• Dense marine life – 90%
• Interesting features and / or bathymetry
• Temperature, visibility & Currents important but
not critical
• Only 13% were wrecks – wrecks needed to be
more than just a sunken ship and need to have
the other attributes such as interesting cargos
and dense marine life.
8. Next Stages
To assist in the environmental impact statement
(EIS) and to optimise the design to facilitate the
rapid development of a complex habitat to achieve
dense and diverse marine life, a monitoring frame is
to be installed on the north site. The monitoring
frame will evaluate a range of shapes and
substrates at different depths.
The results from the monitoring structure will enable
the eco-engineering of a world class purpose built
dive attraction for the Gold Coast.
9. Acknowledgments
The investigation team acknowledges and
appreciates funding provided by the Gold Coast City
Council that enabled this project to be undertaken.
We would also like to thank the generous
assistance offered by Dr. Daijiro Kobashi in his
interpretation of the inshore coastal oceanography,
Mr. Ian Banks for his excellent photography and
diving advice and the Queensland Museum for
assistance in identifying various organisms found on
site.
10. References
[1] Restall, J. Corbett B. Tomlinson, R Jackson, A.
(2012) 12 months Site Monitoring of Preferred Dive
Site for a Gold Coast Dive Attraction. Report
prepared for Gold Coast City Council by
International Coastal Management and Griffith
Centre for Coastal Management.
[2] Restall, J. Hughes, L. Richards, R. Kobashi, D.
Corbett B. Tomlinson, R Jackson, A. (2013) 12
month site monitoring of alternative site for a Gold
Coast dive attraction – Tugun / Currumbin. Report
prepared for Gold Coast City Council by
International Coastal Management and Griffith
Centre for Coastal Management.
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