Department of State Development, Infrastructure and Planning, Queensland Government Gold Coast Broadwater Marine Project Cruise Ship Terminal Feasibility Assessment Report Ref: 228980-DOC-01 3 | 21 June 2013 This report takes into account the particular instructions and requirements of our client. It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party. Job number 228980 Arup Arup Pty Ltd ABN 18 000 966 165 Arup Level 4, 108 Wickham Street Fortitude Valley QLD 4006 GPO Box 685 Brisbane QLD 4001 Australia www.arup.com
Transcript
Department of State Development, Infrastructure and Planning, Queensland Government
A desktop study has been undertaken to determine the technical feasibility of a cruise ship terminal on the Gold Coast Broadwater.
A cruise ship terminal on the Broadwater is likely to be a transit port (not a base port) and at a minimum will require dredging to provide access, a berthing and mooring structure, a terminal building and land transport connection.
Preliminary navigation studies performed to date show that it is safe for highly manoeuvrable vessels up to 312m to navigate through the seaway subject to operational wind and current restrictions. Tug assistance will be required by cruise ship operators.
Subject to further navigation studies, capital dredging and annual maintenance dredging for a 160m wide approach channel, navigation channel through the Seaway and a 500m diameter swing basin and a berth pocket will be required.
Key potential impacts of the cruise ship terminal are primarily associated with the dredging works, for which existing studies have shown:
• Water levels in the Broadwater (fluvial flood, tides, storm surges) and hence the flood risk.
- There would be a small reduction in fluvial flood levels hence a
reduction in fluvial flood risk.
- There could however be a small increase in tides (±1 to 4cm) and
changes in storm surges levels (-0.1m for coast crossing and +0.1m for
coast parallel storms).
- Effect of sea level rise (0.8m by 2100) has not been studied.
- These could potentially be mitigated by selecting the location with the
least impact, balancing of dredging and reclamation works for the
overall project.
• Wave conditions in the Broadwater – there could be increase in wave heights in the Seaway and to the east of Wavebreak Island. Such localised increment is unlikely to have a significant effect in the Broadwater, although there could be erosion concern on the eastern frontage of Wavebreak Island.
• Current flow – a reduction in the current flow velocities in the Seaway is expected with the channel widening and deepening within the Seaway. Potential impacts on:
- Seaway revetment and breakwater – the reduction in the current flow
velocities in the Seaway will help in reducing the scour of the
revetment and breakwater. However, from an operational point of view
it is recommended that the revetment and breakwater are improved to a
higher factor of safety against slip failure.
Department of State Development, Infrastructure and Planning, Queensland Government
- Existing recycled water release system – the reduction in the current
flow velocities between the training walls would likely to reduce the
‘flushing’ capacity of the Seaway slightly. Such reduction may result
in the water quality in the Broadwater exceeding the acceptable limit
earlier than 2018, although the improved tidal exchange may suggest
otherwise, hence requires further investigation. There is also concern
about impacts on eddies formation east of Wavebreak Island.
- Planned Ocean Release system – there is a risk of ‘backflow’ of
recycled water released in the Ocean back to the Broadwater with the
dredging works through the ebb tide delta. Such risk cannot be
qualified at this stage as the modelling works of the Ocean release
system has been based on the existing ebb tide delta.
- There would be a slight reduction in the wave height at TOS which
could be mitigated by placing appropriate quantities of dredged
material at an appropriate location north of the channel, to be
determined using modelling works.
• Sand by-pass pipes – the sand by-pass pipes would need to be lowered to lower than -13mLAT and potentially requires protection against anchor strike.
• Recreational boating and diving activities – depending on the location of the cruise ship terminal, the recreational boating and diving activities in the Broadwater may be adversely affected including loss of anchorage areas.
• Commercial boating – despite the temporary disruption to commercial boating during the construction and cruise ship navigation, there could be positive impact on the navigation of commercial boating taking advantage of the deeper and wider channel. Commercially the cruise ship terminal would attract more business for the commercial boating activities.
The extent of these impacts rests on the preferred location, layout and dredging requirements, and other dredging/reclamation works associated with the overall Gold Coast Broadwater Marine Project. Particular focus should be on limiting and mitigating the impacts on storm surge level and the recycled water release systems for the feasibility of the cruise ship terminal.
Environmental impacts - the project is expected to impact the diverse ecology and valued public space of the area, requiring federal approval under the Environmental Protection and Biodiversity Conservation Act 1999. Environmental feasibility of a cruise ship terminal is dependent on comprehensive identification of specific impact, scale and management and mitigation options. It is reasonable to expect that conditions will include biodiversity offsets, monitoring and management programs and public consultation.
The dredged volumes determined for costing purposes are:
Capital dredging volume: 4 million m3 ±1 million m3
Further risk on the capital dredging cost lies on the acid sulphate soils potential of the indurated sand.
Other major capital cost items are assessed as follows:
Berthing and Mooring Structure: $17.5 million to $24.5 million
Terminal buildings: $7.6 million
It is recommended that beneficial re-use of the dredged material be practised in future maintenance dredging works for the cruise ship terminal. It is however noted that this would require further discussion between Gold Coast Waterways Authority and the cruise ship terminal operator on the share of the maintenance dredging costs; and similarly with the Gold Coast City Council who would receive the dredged material for beneficial reuse.
Department of State Development, Infrastructure and Planning, Queensland Government
The Queensland Government (“the State”) and Gold Coast City Council (“the Council”) are working collaboratively to promote economic development on the Gold Coast where opportunities exist on state-owned land on the Southport Broadwater, including Wavebreak Island and the Spit to develop a Broadwater Marine Project (“the Project”).
Components of the Project may include a cruise ship terminal and integrated developments such as a casino, hotel, super yacht facility, residential development, other tourism related infrastructure and provision of upgrades to the existing infrastructure such as the road network (including the possibility of construction of new bridges), water treatment plant upgrades and other hard infrastructure.
Expressions of Interest (“EOIs”) have been sought for proposals for the Project and four proponents have been shortlisted for the Requests for Detailed Proposals (“RFDP”) stage.
1.2 Project Site Location
The Project site location is illustrated in the following figure.
Figure 1: Project site location
Department of State Development, Infrastructure and Planning, Queensland Government
This report summarises the feasibility assessment of the Cruise Ship Terminal (“CST”) in Gold Coast Broadwater. The assessment was undertaken as a desktop study based on existing studies listed in Section 2.
This report is to inform the State on the feasibility of the Cruise Ship Terminal on technical grounds. A commercial feasibility study is being undertaken by PriceWaterhouseCoopers (PwC) for the State.
Department of State Development, Infrastructure and Planning, Queensland Government
There have been a number of studies undertaken for the proposal of a cruise ship terminal in Gold Coast Broadwater, most notably:
• GHD undertook a Notional Seaway Environmental Impact Statement (“EIS”) in 2006 for the Queensland Government (“the 2006 Study”)
• In 2012 the Council revisited the CST proposal in the 2006 Study and commissioned a number of studies relating to the CST (hereafter collectively referred to as “the 2012 Studies”):
• AEC, 2012, Gold Coast Cruise Ship Terminal Business Case
• Meridian Maritime Services, 2012, Navigation Simulation Study
• BMT WBM, May 2013, Working Draft Preliminary Coastal and Hydrodynamic Investigation for Cruise ship Terminal Options (final version expected in June 2013)
A number of studies have been undertaken within or in proximity of the Project site, further described in Section 2.4.
2.2 The 2006 Study
The 2006 Study is an EIS for a CST to be located at the confluence of the North Channel, South Channel and the Gold Coast Seaway (the Seaway) at the northern end of The Spit (Figure 2). The 2006 study contains significant amount of information and knowledge relating to the cruise ship terminal and the site.
Figure 2: Conceptual design of the 2006 Study CST
The 2006 Study covered a range of areas including the project need, the conceptual design, location, construction and operation, land tenure, infrastructure
Department of State Development, Infrastructure and Planning, Queensland Government
requirements, waste management, land, climate, water resources, coastal environment, air quality, waste, noise and vibration, nature conservation, cultural heritage, social environment, health and safety, economy, hazard and risk and environmental management.
It also contains appendices including the consultation report, social impact assessment, dredging strategy, noise modelling results, transport modelling results, wave modelling results, water quality report, hydrodynamic modelling report, sediment sampling and analysis, air quality, navigation simulation, flora and fauna searches, cultural heritage management plan and a report pertaining to matters of national environment significance.
Overall the 2006 study provided a sound assessment of the design at the time. However there is significant risk in using this information as the basis for any future assessments or determinations. There are several information and investigation gaps to this 2006 study, a number of these are identified in Section 5.7.
The 2006 study was based on a single option as shown in Figure 2. The preferred location and size of the CTP together with other tidal works in this Project will require further dredging, noise & vibration assessments, hydrodynamic modelling and a greater understanding of the impact.
Department of Sustainability, Environment, Water, Population and Communities (SEWPAC) and the Coordinator General have become more stringent with environmental assessment requirements since 2006. This should be taken into consideration as additional studies/detail may be required that was not previously requested in the 2006 Terms of Reference.
2.3 The 2012 Studies
Since 2012, the Council revisited the cruise ship terminal proposal in the 2006 Study and commissioned a number of studies to further investigate the feasibility of a CST in Gold Coast Broadwater.
These studies looked at a range of transit port locations in addition to the one proposed in the 2006 EIS Study as a down sized transit terminal. The Council resolved to investigate 3 options, North of Sea World, South of the entrance and an option at Southport (Options 1, 3 and 6 shown in Figure 2). The business case study undertaken by AEC (2012), as understood from the Council, is related to Option 3 in Figure 2.
Department of State Development, Infrastructure and Planning, Queensland Government
Figure 3: Locations for CST considered in the 2012 Studies by the Council
It should be noted that at the time of writing, modelling works are being undertaken as part of the Coastal and Hydrodynamic Investigation for Cruise ship Terminal by BMT WBM, to be finalised in June 2013. The study aims to assess the impact of a CST on the tidal hydrodynamics, storm surge, flooding, wave climate, sediment transport, coastal process and recycled water release assessments.
Preliminary modelling results were provided by BMT WBM in a working draft report that was received in May 2013. These preliminary modelling results are the best available information about impacts on hydrodynamic regime. They are further discussed in Section 4.5.1.
Department of State Development, Infrastructure and Planning, Queensland Government
This study reviewed the efficiency of operation of the Seaway and assessed the sediment transport rates at the Seaway.
Worley, WMB and DesignInc, 2003, Final Options Definition Report Project Princess
In 2003, Worley, WMB and DesignInc completed a technical study of five cruise ship terminal locations on the Broadwater. The study addressed engineering, environmental, operational, planning and costing aspects to assess the viability of a CST on the Gold Coast. The study also reviewed numerous previous studies including the Council’s flood modelling works, and WBM Ecological and Hydraulic studies, Australian Maritime College navigation study and Connell Wagner engineering feasibility of four cruise ship terminal locations.
Griffith Centre for Coastal Management, 2006, Evolution of Coastal Inlets of Queensland Gold Coast Seaway
The Griffith Centre for Coastal Management compiled a series of historical aerial photographs showing the trend of inlet evolution of the Gold Coast Seaway.
GHD, 2011, Report for Gold Coast Waterways Access Needs Study GHD was commissioned by the Department of Transport and Main Roads to conduct a review of the marine industry’s perceived need for navigational channels in the Gold Coast waterways. The study conducted stakeholder consultation, identified user demand and developed a preliminary dredging strategy. The study conducted cost benefit analysis and investigated funding options.
EC3 Global in partnership with RPS completed a study for the Gold Coast City Council which reviewed the tourism value of the waterways, type of commercial users, areas accessed and identified areas of potential development.
BMT WBM, 2011, Gold Coast Seaway Channel Scour and Rock Wall Stability Investigation
BMT WBM reviewed historical navigation surveys which showed that the seaway is continuing to scour. BMT WBM’s sub consultant Coffey Geotechnics reviewed the stability of the training walls and found that the factor of safety is “in the order of 1.0” in some areas.
Department of State Development, Infrastructure and Planning, Queensland Government
VDM Consulting, 2012, Ecological Investigation to Support the Broadwater Masterplan
VDM Consulting presented a report on the findings of their ecological investigations to assist the development of a Broadwater Masterplan. VDM Consulting conducted field surveys in March and April 2012 which investigated four components; terrestrial vegetation (e.g. mangroves), shorebirds (waders), seagrass, intertidal macroinvertebrates and marine vertebrates.
BMT WBM, 2012, Gold Coast Seaway Preliminary Training Wall Stability Improvement Investigation
BMT WBM investigated the technical feasibility of increasing the bank stability by providing rock material on the sloping bank. The study provided two rock slope profiles options that would result in a factor of safety of 1.2 and 1.5. Appendix C provides details of the typical cross sections of the seaway walls.
Gold Coast City Council, 2013, Broadwater Marine Project Planning Approvals and Offsets
This paper was compiled by the Council to summarise the environmental, planning and approvals considerations of the Gold Coast Broadwater in the context of proposals specifically for a cruise ship terminal, development of Wavebreak Island and a casino.
Department of State Development, Infrastructure and Planning, Queensland Government
The tidal regime at the Gold Coast Seaway is semi-diurnal and Table 1 provides information on the predicted astronomical tide level.
Table 1: Predicted Tidal Levels at Gold Coast Seaway (http://www.msq.qld.gov.au/Tides/Tidal-planes.aspx, accessed on 13 May 2013)
Tidal Plane Level (mLAT) Level (mAHD)
Highest Astronomical Tide (HAT) 1.91 1.15
Mean High Water Springs (MHWS) 1.42 0.66
Mean High Water Neaps (MHWN) 1.13 0.37
Mean Sea Level (MSL) 0.76 0.00
Australian Height Datum (AHD) 0.76 0.00
Mean Low Water Neaps (MLWN) 0.39 -0.37
Mean Low Water Springs (MLWS) 0.11 -0.65
Lowest Astronomical Tide (LAT) 0.00 -0.76
3.1.2 Storm Surge Level
The 2006 study reviewed extensive storm tide modelling conducted by CSIRO in 1998 and 2000. The 100 year return period storm tide levels for the Broadwater and Seaway/Ocean are 2.32m and 2.47m AHD respectively. It is noted that “These estimated water levels have taken into account a 27cm sea level rise due to global warming, the combined effects of tropical cyclones, east coast lows and distant cyclones.”
Considering the MHWS of 0.66mAHD, the storm surge allowance for the 100 year return period event excluding sea level rise to 2006 is 1.39m and 1.54m at the Broadwater and Seaway respectively.
3.1.3 Wave
Offshore/Ebb Tide Delta
The 2006 study summarised the offshore wave climate based on the Gold Coast waverider buoy which is located approximately 3km south of the Seaway in 18m of water. The study concluded that predominate waves are in the range of 0.75m to 1.25m with 8 to 10 sec period. The maximum significant wave heights (Hs) are typically around 5m which a maximum recorded Hs of 9m. However, it is noted the wave heights at the Seaway will be depth limited to around 5m.
Department of State Development, Infrastructure and Planning, Queensland Government
Wave modelling was performed as part of the 2006 study and concluded that “In the existing Seaway the wave climate is characterised by a predominant wave of 0.6 to 0.8 m with 8 sec period. In the swing basin [to the east of Wavebreak island] the wave climate is characterised by a predominant wave in the 0.4 to 0.6m range with 8 sec period.”
There were no references to the return period of these wave conditions.
3.1.4 Currents
The tidal hydrodynamics in the Broadwater have been extensively studied and with the most recent study being the on-going BMT WBM’s “Coastal and Hydrodynamic Investigations for Cruise Ship Terminal Option”.
The 2006 study conducted a hydrodynamic model to assist sediment transport and dredging flume modelling. The 2006 study concluded that peak tidal velocities in the Seaway typically exceed 1.2m/s (2.3 knots) under mean spring tidal conditions.
It is reported that the Seaway is receiving river discharge from the North and South channels at a 70:30 split (see Figure 4). As a result there is a formation of helical currents that arrive at the Southern Seaway revetment and are reflected to the offshore end of the Northern Seaway breakwater. The Northern breakwater of the Wavebreak Island is also exposed to high current flow. The sea bed along the main flow path has had scour holes forming in close proximity to the Northern breakwater of Wavebreak Island, the Southern Seaway revetment and the offshore end of the Northern Seaway breakwater.
Figure 4: Plan showing the current flow path in an ebbing tide
Department of State Development, Infrastructure and Planning, Queensland Government
Historic wind data for the Gold Coast Seaway (Site number 040764, Latitude -27.94°, Longitude 153.43°, elevation 3m) is available from the Bureau of Meteorology (BOM) from 1987 until 2013. The 9am and 3pm wind rose for the Gold Coast Seaway can be seen in Figure 5 and Figure 6.
Figure 5: Gold Coast Seaway 9am Wind Rose from Dec 1991 to 30 Sep 2010 (Bureau of Meteorology, May 2012).
Department of State Development, Infrastructure and Planning, Queensland Government
Figure 7: Wind Rose for Period November 1989 to March 2006 provided in the 2006 study (Bureau of Meteorology 2006)
These roses show that there are shore-parallel winds that need to be considered in the navigation design because they are cross-winds for ships entering and leaving the Seaway.
3.2 Bathymetry
The bathymetry of the Gold Coast Seaway is regularly surveyed. The 2006 study and the WBM studies of the rock wall scour and stability (WBM 2011 and WBM 2012) indicated that since the construction of the training walls and sand by-pass system in 1986, the Seaway has been surveyed for navigation purposes annually to 1993 and typically 6-monthly after that. This is confirmed by Gold Coast Waterways Authority (“GCWA”) in a workshop on 7 May 2013. GCWA also confirmed that bathymetric survey is also undertaken following major storm events.
Department of State Development, Infrastructure and Planning, Queensland Government
The bathymetry data is available in the Project data room.
3.3 Sediment Transport
The Gold Coast beaches are exposed to predominantly south-easterly ocean waves which result in significant northerly longshore sand transport. There have been extensive studies on the longshore sediment transport since the first Delft Hydraulics Laboratory investigations in 1970.
The first sediment pathways concept was presented by WBM Oceanics (2001) as illustrated in the following figure.
Figure 8: Sediment pathways and rates near Seaway entrance (extracted from Figure 4.1, WBM Oceanics (2001))
In this sediment pathway concept, the sand transport at the Seaway ebb tide delta is subject to numerous sources including leakage past the by-passing jetty (from a
Department of State Development, Infrastructure and Planning, Queensland Government
northerly alongshore sediment transport of 635,000m3/year), discharge leakage north of Seaway and scour from the Seaway.
It is also reported that the ebb tide delta has grown at a rate of 450,000m3/year between 1986 and 1990; and approximately 200,000m3/year in 1990s. Based on an annual growth rate of 200,000m3, the model assumes that the total southerly sediment transport rate and the discharge leakage north of Seaway is equal to the sediment transport rate off the delta.
The 2006 Study reported that gross northerly alongshore sediment transport could be 33% higher than WBM Oceanics (2001) estimate, approximately 846,000 m3
. It also states that “An analysis of the recent surveys of the ebb tide delta indicates an average growth of 137,000 m
3/year but this varied between 100,000 m
3 scour
to accretion of the same amount in consecutive years. Nevertheless, the recent decrease in the ebb tide delta growth is consistent with the increase in the amount of sand pumped through the sand by-passing system.”
Building on the sediment pathway concept by WBM Oceanics (2001), the 2006 Study considered that with a 75% efficiency of by-passing pumps there will be 186,000m3 of sediment leakage at the by-pass. Together with scour from the Seaway there will be an annual accretion of the ebb delta around 200,000m3. This model assumes that the rate of material scoured from the Broadwater is equal to the rate of the material leaving the ebb tide delta. There is no explanation on the use of 200,000m3 despite an earlier statement that the ebb tide delta is growing at 137,000m3 per year.
Figure 9: Sediment Pathways and Quantities (GHD, 2006)
GCWA undertook a study comparing the bathymetry data in the Broadwater between 1983 (prior to the construction of the Seaway) and 2009. The data comparison shows a reduction of sediment in the Broadwater by approximately 16 million m3. Considering reclamation of Wavebreak Island and other dredging works in the Broadwater, it was estimated that the volume of sediment exported
Department of State Development, Infrastructure and Planning, Queensland Government
from the Broadwater could be in the region of 11.3 to 14.8 million m3. This equates to an annual export of 430,000m3 to 570,000m3 on average, although a sizeable amount of the sediment export is expected to have happened soon after the completion of the Seaway.
3.4 Gold Coast Seaway
Historically, the natural estuary of the Nerang River entrance and Broadwater was a dynamic coastal system defined by shallow, mobile and shifting channels and sand bars. The Nerang River entrance was slowly moving north and varying in width and depth which posed a hazard to navigation.
In 1986 the Seaway was completed to form a permanent navigation entrance from the Pacific Ocean into the Broadwater. The permanent entrance was formed by two parallel training walls, in the form of rock revetment (armoured on the one face) and breakwaters (armoured on both faces) as they extend into the sea.
Wavebreak Island was constructed as part of the Seaway project to protect the mainland from extreme wave conditions through the Seaway. There are rock breakwaters at the northern and southern ends of the eastern frontage of Wavebreak Island.
To mitigate disturbance to the alongshore sediment transport a sand by-pass system was put in place when the Seaway was built. The sand by-pass system consists of a sand pumping jetty and a pipeline that run across the Seaway. The Seaway was originally designed and dredged to -6mLAT and the sand by-pass pipeline was originally installed at -10mLAT, 4m below the seabed level.
The Broadwater, in close proximity to the Seaway, requires regular dredging to maintain design navigation depths. This includes regular dredging of the South Channel, North Channel and the South Wavebreak Island Channel. Navigation channel maintenance dredging is currently the responsibility of the State Government through the GCWA. Similarly, through GCWA, the State Government is responsible for the maintenance of the training walls, the sand-by pass system and breakwaters on Wavebreak Island.
Due to the dominant flow from the North Channel discussed in Section 3.1, the Seaway has experienced erosion along the main flow path and some parts are now deeper than 17m. The sand by-pass pipeline that crosses the Seaway is now in suspension with piled supports. From the survey drawing of the pipeline and the existing piled supports (see Appendix B) the pipeline is at a level -5mLAT sloping down to -12.5mLAT at the lowest point, while the top of the piles are approximately 1m higher than the pipeline. GCWA advised that they have a project underway to improve the stability of the pipeline through the addition of more supports and some smoothing of the pipeline levels.
There are scour holes in close proximity to the northern Wavebreak Island breakwater, the southern Seaway revetment and at the offshore end of the northern Seaway breakwater. The erosion has reduced the slope stability of the southern Seaway revetment.
GCWA advised that the erosion adjacent to the revetment and breakwater started not long after the Seaway was constructed and has been monitored since construction. The current slope stability of the revetment and breakwater has been assessed by WBM (2011) to have a factor of safety of between 1 to 1.15. This is
Department of State Development, Infrastructure and Planning, Queensland Government
marginally above the safety requirement for a slope failure. There are warning signs in place to warn members of the public about the risks of rocks moving on the revetments/breakwaters.
The current monitoring of the erosions/scour includes half-yearly hydrographic survey and survey following major events. Over the years GCWA and its predecessors have engaged WBM to undertake a number of studies, and most recently the following studies:
• BMT WBM (2011) report provided a revised recommendation for annual monitoring surveys and concluded that: “There is evidence that the entrance channel is continuing to scour. However, since the early 1990’s this has been spatially rather than deepening of the existing holes. The rate of scour appears to be decreasing and is currently about 20,000 m
3/year. It is likely
that the channel will increase in area, i.e. scour, until an area proportionate with the tidal prism is reached. At the current rates of change this could take another 5-10 years under current conditions. This could be extended by events which may increase the tidal prism such as canal development, channel dredging and sea level rise. With regard to the training wall stability, the geotechnical assessment has indicated that the factor of safety has reduced to around 1.0 in some areas near the scour holes. These values indicate marginal stability unless remedial measures are carried out. An investigation of remedial actions is recommended. These may include rock protection of the bank slopes, channel flow re-balancing or possible re-design of the training wall sections.”
• BMT WBM (2012) provided two remedial options to increase the factor of safety of the slope stability to 1.2 and 1.5. The report noted that the assessment was preliminary and that detailed design would require “better information on existing materials in the training walls, better knowledge on 3D effects and morphological responses including the deepening or extension of the scour holes.”
It is understood from GCWA that there is no current plan to strengthen the breakwaters/revetments but to continue monitoring the scour holes.
3.5 Recycled Water Release System
The Gold Coast Water (GCW) recycled water is being released at the Seaway through a number of diffusers along the northern bank of Seaway (“the Northern release”) and at the southern bank of Seaway (“the Southern release”), as illustrated in the figure below.
The recycled water release system is optimised to allow for discharge on the ebbing (out-going) tide. The Northern release is expected to reach capacity by 2015-2020 while the capacity of the Southern release is expected to be exceeded by 2024.
It is noted that the Northern release receives recycled water through a pipeline laid on the seabed to the north of the Wavebreak Island from the main land to South Stradbroke Island. The following figure shows the alignment of the pipeline.
Department of State Development, Infrastructure and Planning, Queensland Government
Figure 10: Plan showing the Northern and Southern release point.
There is currently a plan to construct a longer term recycled water release system that releases recycled water directly into the ocean (hereafter referred to as “Ocean Release system”). There are currently two options are being considered, one to the North of Seaway and the other to the South of Seaway. Layout plans of the two options are shown in the following figures. It is noted that the modelling work to confirm the preferred option is underway and expected to be completed by December 2013.
Figure 11: Plan showing the planned Ocean Release system to the south of the
Seaway.
Department of State Development, Infrastructure and Planning, Queensland Government
It is considered that at a minimum the following infrastructure/facilities must be provided:
• dredged navigation channel including through the Seaway delta;
• dredged berth pocket;
• berthing and mooring structure;
• terminal buildings and paved areas for passenger set-down; and
• land transport link.
It is noted that the business case study undertaken by AEC (2012) assumes that the port will not be used for international cruises and therefore customs, quarantine or baggage handling facilities would not be required.
While operating the CST as base port would potentially attract significantly more spending by tourists at Gold Coast, it has much higher capital costs considering the utility services including fuel bunkering, water supply, waste facilities and baggage handling that would need to be provided. It is therefore considered it is more realistic to operate the CST as a transit port. This has been the assumption in the business case developed by AEC (2012).
4.2 Ship Size
The size of the design vessel for the CST will define the size of the required berthing and mooring structure, berth pocket, approach channel and swing basin.
The 2012 navigational study concluded that vessels up to 312m LOA can safety enter the Gold Coast Seaway subject to vessel manoeuvrability and metocean restrictions (see Section 4.3) It is noted that this study was undertaken primarily with conceptual elements and further studies are required.
AEC (2012) conducted a review of cruise ships that have previously visited Australia as well as the possible future demand. AEC (2012) made an assumption that vessels larger than 300m Length Over All (LOA) would not be able to enter the Seaway. AEC (2012) also states that there is a trend towards larger cruise ships.
4.3 Navigation Study
The following cruise ship navigation studies have been identified:
• Appendix M Further Navigation Simulation Report of the 2006 Study; and
• Meridian Maritime Services, 2012, An investigation into the feasibility of piloting large cruise ships to and from a proposed terminal within the Gold Coast Broadwater”
Department of State Development, Infrastructure and Planning, Queensland Government
The 2005 and 2006 studies were performed using the “Star Cruise Ship Simulator” in Malaysia while Meridian Maritime Services used the Smartship Australia facility in Brisbane.
The 2005 and 2006 simulation studies used three ship models shown in Table 2. The simulations assumed a turning circle located to the east of Wavebreak Island, with the cruise ship berth located on The Spit.
Table 2: Vessel parameters for MSQ ship simulation
Vessel Name Length Over All (LOA) [m]
Beam (B) [m] Draft (D) [m]
Superstar Leo 268 32.2 8.01
Golden Princess 289 36.0 8.05
Arcadia 245.6 32.2 8.00
The 2005 and 2006 studies found that “Vessels up to 300m and equipped with twin screw, twin rudders, bow and stern thrusters and a NACOS-45 integrated bridge system or similar can be handled with relative ease within the channel and swing basin with 20 knot wind limit and moderate tidal conditions.”
Meridian Maritime Services (2012) found that vessels up to 312m LOA are able to safely access the Gold Coast subject to conditions operational limits. It recommends an operational wind limit of 25 knots; however this wind speed is reduced to 20 knots when the current exceeds 50% of the peak speeds.
Both the 2006 Study and Meridian Maritime Services (2012) noted vessels must have a high degree of manoeuvrability and that vessels without stern thrusters would generally not be able to berth without tug assistance. The studies also discussed operational tidal limits to avoid departing on an ebb spring tide and entering on a flood spring tide.
It is noted that tug assistance was not included in the Meridian Maritime Services (2012) navigation simulations. However, the Council advised that tug assistance is required by cruise ship operators during the consultations undertaken for the AEC (2012) study.
All of the above navigational studies used a channel width of 130m and swing basin of 500m. Meridian Maritime Services (2012) concluded by recommending a channel width of 140m.
A peer review of the Meridian Maritime Services (2012) study has been undertaken as part of this report by Kerry Dwyer Maritime Consultants (see Appendix A). This review identified a few concerns that should be clarified in further studies including: non-compliance of some of the navigation simulations with the stated objective of staying one beam width clear of the dredged toe-line; inadequacy of the 500m diameter swing basin proved in a number of simulations; no ordinary set of circumstances creating a channel through a sand delta; and use of ‘sloping channel edges and shoals’ instead of ‘steep and hard embankment’ in the consideration of bank effects. Kerry Dwyer Maritime Consultants recommended that the channel width at the approach channel would more likely be 160m. It is recommended that further simulations works in conjunction with the preferred location and layout of the CST are undertaken to confirm this recommendation.
Department of State Development, Infrastructure and Planning, Queensland Government
Arup considers that with tug assistance, the 500m diameter turning circle could potentially be adequate, to be verified in navigation simulations.
4.4 Capital Dredging
The 2006 Study assumes 3 million m3 (including marina in Marine Stadium) of capital dredging while the AEC (2012) assumes 4.1 million m3 capital dredging. The required dredging will highly depend on the chosen location of the CST and swing basin.
The volume of the capital dredging works varies with the location and size of the CST. Based on the estimates for a range of options undertaken by the Council, the volume of the capital dredging works would be in the region of 3 to 5 million (see Figure 3). For the purpose of this report and the commercial feasibility study by PwC, it is considered that a non-location specific estimate of 4 million m3 is used, with sensitivity tests for ±1 million m3, is representative of the capital dredging works required.
The 2006 Study indicated that the majority of the material to be dredged is clean medium to coarse grain sands. However, approximately 330,000m3 of the material, located in the western portion of the swing basin below -6.5m LAT, is expected to be dark brown humic sands with some coffee rock, parts of which have been identified as having acid sulphate soils potential.
4.5 Maintenance Dredging
The required maintenance dredging will be highly dependent on the hydrodynamics and bed shear stress and resulting sand transport of the dredged bathymetry. BMT WBM is currently modelling the expected sand transportation impacts of three CST options. Whilst the total sedimentation rates have not been done, the draft BMT WBM (2013) report indicated that the sediment deposition in the dredged areas can be as high as 160,000m3 over a four-month period including a storm event.
The 2006 Study discussed the options of high capital dredging design with a generous provision for siltation compared to low capital dredging design with frequent maintenance dredging. It assumed maintenance dredging of 150,000m3 annually from outer entrance channel and 200,000 m3 (dredged biannually) from the swing basin, totalling at 350,000 m3 per year. It is however not clear how this has been derived from the sediment pathways and quantities estimate discussed in Section 3.3.
The 2006 Study also recommended an additional allowance of 150,000m3 for material that erodes from Wavebreak Island and 300,000 m3 for re-design/ optimisation of the channel and sand traps.
AEC (2012) assumed 385,000 m3 of material will need to be dredged every year; however the justification for this quantity is unclear.
At this stage, based on the works done to date described in Section 3.3, there is no clear indication whether the leakage of the sand by-passing system or the erosion in the Broadwater is the primary source of the ebb tide delta. However, the estimates to date appears to lie with the annual growth of the ebb tide delta that was around 200,000 m3/year, reducing from 450,000m3/year immediately after the
Department of State Development, Infrastructure and Planning, Queensland Government
completion of the Seaway. Recent reduction in the ebb tide delta growth rate to 137,000 m3/year may suggest the ebb tide delta is growing towards an equilibrium size.
In the absence of the result of the sedimentation study, it is considered that the average yearly sedimentation rate is between 200,00m3 to 400,000m3 and more likely to be between 300,000m3 and 400,000m3 with the widened and deepened channel and swing basin that encourage sedimentation. A 350,000m3 total yearly maintenance dredging volume estimated by the 2006 Study is hence considered adequate for costing purposes at this stage. It is however recommended that in the commercial feasibility assessment by PwC, sensitivity tests are undertaken for ±50,000m3 of maintenance dredging every year.
4.6 Summary
A CST on the Gold Coast will likely be a transit port and at a minimum will require dredging to provide access, a berthing and mooring structure, a terminal building and land transport connection.
Preliminary navigation studies have been performed which show that it is safe for highly manoeuvrable vessels up to 312m to navigate through the seaway subject to operational wind and current restrictions. These wind and current restrictions are likely to restrict vessel arrival and departure times. It is likely that tug assistance will be required for older and less manoeuvrable cruise ships. It is recommended that tug assistance be provided for all vessels for the first few years of operation.
Subject to further navigation studies, capital dredging and annual maintenance dredging for a 150m wide entrance channel, a 500m diameter swing basin and a berth pocket will be required. It is expected that part of the dredging would potentially encounter indurated sands, parts of which have been identified as having acid sulphate soils potential. If encountered, both would have cost implications.
For costing purposes, it is recommended that the following volumes are used:
The dredging works required for the CST could result in impacts on estuarine and coastal processes, the Seaway, the recycled water release system, recreational activities, commercial activities and the environment. The following describes these potential impacts based on findings of the existing studies.
It is noted that the extent of these impacts and the associated mitigation measures will depend on the preferred CST location, layout and dredging requirements, together with any dredging (e.g. for marinas) and land reclamation of the wider Broadwater Marine project. The cumulative impacts of all of the work elements seaward of the high water mark must be modelled to prove that the works are having imperceptible impacts and if required the necessary mitigation measures.
5.2 Estuarine and Coastal Processes
Dredging works to allow for the safe navigation of the cruise ships have potential impacts on the coastal process in the Broadwater, the Seaway and immediately offshore of the Seaway. These coastal processes include tidal hydrodynamics, storm surge, wave climate, flooding, sediment transport and sedimentation (sediment deposition).
The draft BMT WBM (2013) report provided preliminary modelling results for the on-going modelling works of the impacts on estuarine and coastal processes.
This study is investigating the impacts of three CST options: Option 1 “Wavebreak” (turning circle between the Wavebreak Island and the Seaway), Option 2 “South Channel” (the navigation channel extended southwards from the Seaway, with a turning circle just north of Sea World) and Option 3 “The Spit” (the navigation channel extended from the Seaway to the Marine Stadium with the turning circle between Wavebreak Island and the Seaway). The modelling does not take into consideration sea level rise.
The following discussions on potential impacts on coastal processes are based on the preliminary results that were provided in the working draft report. It shall be noted the further numerical modelling works will be required to confirm these impacts as the project progresses.
5.2.1 Tides
The preliminary results show that Options 1 and 3 would increase the high tide level by 1 to 2cm and decrease the low tide level by 1 to 2cm. Option 2 results in high tide level increasing by up to 4cm and low tide level decreasing by up to 5cm, predominantly to the south of the Seaway.
Sea level rise, which in accordance with the Queensland Coastal Plan would be 0.8m by 2100, has not been incorporated in the modelling.
Changes in tidal levels would have impacts on the flood risks if coupled with storm surge/flooding levels. This has not been considered by BMT WBM (2013).
Department of State Development, Infrastructure and Planning, Queensland Government
Changes in tidal current velocities may have impacts on the scour holes near the Seaway training walls and the water quality in the Broadwater.
The preliminary modelling results show that in all three options there is a slight reduction in tidal current velocities in the Seaway which could help slightly reducing the scours near the revetment and breakwater described in Section 3.4. Results of all the options show a significant increase in velocities in the dredged channel offshore of the Seaway during ebb tides, but these are concentrated at the offshore end of the dredged channel.
The modelling shows some very localised (>0.1m/s) increase in tidal velocities for Options 1 and 3 to the east of the Wavebreak Island during both flood and ebb tides. The effects of Option 2 are higher compared to the other two options.
5.2.3 Storm Surge Levels
Changes in storm surge levels will have an impact on the coastal flood risk.
BMT WBM (2013) investigated two 940hPa storm (cyclone) tracks; one with the storm crossing the coast to the north, and the other with the storm tracking parallel to the coast. There is no mention of the return period associated with the 940hPa storms but stated that it is “a Maximum Probable Intensity event for the Gold Coast”. The modelling does not include the effect of tides.
Without the dredging works (i.e. the baseline), the peak storm surge levels for the storm crossing the coast to north is higher, 0.9m, compared to the storm levels for the storm tracking parallel to the coast, 0.5m. Both of these are lower than the 100 year event storm surge allowance of 1.39m and 1.54m at the Broadwater and Seaway respectively, as discussed in Section 3.1.2.
For the coast-crossing storm, preliminary modelling results show that the dredging works will result in up to 0.1m reduction in the storm surge levels in the Broadwater to the south of the Seaway, in particular the southern Gold Coast canals.
For the coast-parallel storm, preliminary modelling results show the dredging works will result in up to a 0.1m increase in storm surge levels. The highest increase is primarily around the Seaway and reduces in the North and South Channels.
It is however noted that BMT WBM (2013) states that “the peak water level in the upper reaches of the river and canal systems is probably substantially over-estimated on topographic reduction factor has been applied to the winds over land (i.e. the wind speeds are representative of ocean winds).”
It is considered that the dredging works will reduce the storm surge flood risk for the coast-crossing storm event (which has a higher storm surge level) but increase the flood risk for the coast-parallel storm event (which has a lower storm surge level). In essence dredging works would potentially improve the storm surge flood protection level of properties that are currently protected against higher storm events, but reduce the storm surge flood protection level of properties that are currently protected against lower storm events.
Department of State Development, Infrastructure and Planning, Queensland Government
The impact on flooding is being investigated for the 1 in 100 return period flood flows with a static MHWS tail water. The preliminary modelling results show that the dredging will result in a slight (<3cm) reduction in flood levels.
5.2.5 Waves
The 2006 Study included wave modelling for both the existing conditions and with the proposed dredging works. The study concluded that the dredging works will have minimal effects on the wave climate throughout the Seaway and adjacent areas and in most cases the differences will be imperceptible.
BMT WBM (2013) indicated that the dredging will result in an increase in wave energy penetrating through the Seaway with a 0.3m increase in the significant wave height to the east of Wavebreak Island. BMT WBM (2013) concludes that this is “expected to induce morphological changes to the eastern shoreline of Wavebreak Island”. It is noted that this is only based on the ‘snap shot’ of one wave event and does not necessarily mean that there will be a 0.3m increase in the median wave climate. Such increase, however, is found to be localised in the Seaway and to the east of Wavebreak Island. It is therefore recommended that the erosion of the eastern frontage of Wavebreak Island is to be studied further.
It is recommended that boat wash effects from the cruise ships be modelled especially for the unprotected eastern frontage of Wavebreak Island and safety of recreational boats.
5.2.6 Surfing Conditions
As discussed in Section 3.3 there is an ebb tide delta immediately offshore of the Seaway. The sediment deposition on the ebb tide delta is believed to contribute to the famous surfing waves at The Other Side (“TOS”).
BMT WBM (2013) considered a snapshot of potential high quality surf conditions at TOS for the Option 1 dredging which showed a minor (0.1m or approximately 5%) decrease in wave height in the vicinity of the surfer’s primary take off point.
It is understood that Professor Andrew Short formally of Sydney University was commissioned by the Council to present at a workshop with the Surfing industry. At this workshop he described the evolution of the surf break at TOS and discussed the likely impacts of dredging a channel for a Cruise Ship through the Seaway Delta. His opinion of the impacts aligned with the 2006 Study that the wave size would not be degraded by the proposal, however it was important to maintain the volume of material on the remainder of the Seaway delta.
It is recommended that modelling works are extended to determine the appropriate location and quantities of dredged material north of the channel to mitigate the risk of reduction in the surfing conditions at TOS.
Department of State Development, Infrastructure and Planning, Queensland Government
BMT WBM (2013) investigated the dredging impacts on littoral zone and estuarine sediment transport using a morphological model.
The study only considered 4 different month-long simulation windows of elevated wave events. During the 4 storm events modelled, sedimentation in dredged footprint ranged from 24,000m3 to up 67,000m3.
The report states that numerical models cannot produce a direct representation of reality and should only be treated as tools used to gain an understanding of morphological systems. This is understood to be the first attempt at morphological evolution modelling at the Gold Coast Seaway and there is significant uncertainty about the results which is highlighted by the 4-month period between mid-February and mid-June 2009. During this period there were multiple significant wave events, and acknowledging there was no dredged channel during this period, BMT WBM (2013) estimated that there was up to 160,000m3 of net sediment transport into the outer channel.
The study does not consider long term sediment modelling or the effect of the fixed sand by-pass system.
5.3 Gold Coast Seaway
5.3.1 Sand By-pass Pipeline
The existing sand by-pass pipeline that crosses the Seaway is at a level between -5mLAT to -12.5mLAT. This is higher than the required draft of 13m for the design ship size recommended by existing studies. It will therefore need to be lowered for safe navigation.
Whilst the risk of anchor strike by a cruise ship is considered low, the revised level of the pipe and a suitable method of protection should be considered.
5.3.2 Revetment/Breakwater
As discussed in Section 3.4, it is understood that the current GCWA strategy towards the scour holes near the revetment/breakwater is to monitor the scour holes and undertake remedial works if, and when, required. There has been no significant remedial works since the construction of the Seaway.
From the preliminary results of the Coastal and Hydrodynamic Investigation for Cruise ship Terminal modelling works (see Appendix A), there are reductions in the flow velocity in both the flood and ebb tides for all the three options modelled. It is therefore expected that dredging works for the CST is unlikely to cause further scouring near the revetment/breakwater. The required draft of 13m also means that there will be no need to dredge in the proximity of the breakwater/revetment affected by the scour. It is however recommended that further modelling works be undertaken for the preferred CST location, layout and dredging requirements.
However, if the revetment/breakwater fails, there could be disruption to the CST operations. Although the failure may not be a hazard to navigation due to the current scour depth of greater than 17m, any emergency remedial works to
Department of State Development, Infrastructure and Planning, Queensland Government
mitigate the risk of unravelling effect would potentially obstruct the port operation. To minimise this risk, it is recommended the slope stability of the revetment/breakwater is improved. It is not unreasonable to consider that the cost of the improvements should be responsible by the CST operator who would be benefiting from mitigating the risk of port operation disruptions.
Should a refurbishment solution be adopted (as recommended by BMT WBM (2012)), Arup recommends adopting the seawall refurbishment option based on a factor of safety of 1.5 for slope stability. The intent of this refurbishment strategy is to provide a long term solution with a low level of maintenance work required to minimise disruptions to the port operation. The indicative cost of the improvement works is expected to be $7.5 million based on estimated 385,000m3
of rocks (taken from BMT WBM (2012)) and an estimated cost rate of $150 for supply and placing. It also includes $400k for mobilisation and demobilisation for the marine plants and a 20% contingency allowance.
Considering the distance between the seawall toe and top of the side slope of the dredged channel (a total dredged channel width of 150m is understood compared to the total seaway width of 300 m), it appears that the seawall refurbishment would not affect the dredging works and vice versa.
5.4 Recycled Water Release System
Section 3.5 described that recycled water in Gold Coast is being released through the Northern and Southern releases. It was also mentioned that the timing of the existing release system has been optimised to ensure that the recycled water is discharged during the ebb tides.
BMT WBM (2013) show slight reduction (0.1m/s) in the flow velocity in both the flood and ebb tides for all the three options modelled. There is a risk that the reduced flow velocity may affect discharging of the recycled water through the Seaway, potentially resulting in an unacceptable level of water quality within the Broadwater. However, the increase in high tide and reduction in low tide levels indicated that the widening and deepening of the navigation channel provides a better exchange of tidal waters. This indicates an overall increase of the ebb tide discharge rate.
GCW advised, in a meeting on 30 May 2013, that the current release system is benefiting from the eddies formed during the ebb tide. Changes in the current flow may affect the formation of the eddies.
It is recommended that water quality modelling works are to be undertaken for the preferred CST location, layout and dredging requirements, together with the predicted recycled water release (prior to the Ocean Release system become operational) to track the recycled water flows and to ensure that the level of water quality will be within the acceptable limits, before commencement of any dredging works.
The proposed dredged channel through the delta offshore of the Seaway for safe navigation of cruise ships may have an impact on the currently planned Ocean Release system. It is recommended that the on-going hydrodynamic and water quality modelling works commissioned by GCW are to incorporate the dredged channel through the delta, to ensure that the dredged channel will not facilitate the
Department of State Development, Infrastructure and Planning, Queensland Government
recycled water flowing into the Broadwater, resulting in an unacceptable limit of water quality within the Broadwater.
5.5 Recreational Activities
To ensure safe navigation, it is expected that the Seaway and Broadwater to the south of Wavebreak Island would need to be temporarily closed to all traffic when a cruise ship enters and exits the Seaway. This is likely be effect recreational boat owners. Surfers which access TOS by paddling across the Seaway would also be affected by the temporary closure of the Seaway.
The dredging of the outer entrance channel is likely to increase accessibility of the Gold Coast to yachts and Superyachts travelling along the Queensland coast. Depending on the location of the CST, the dredged access channel has the potential to improve the navigability of recreational vessels through the Seaway.
The training walls and exposed sand bypass pipeline are believed to be currently used as a local diving site. The lowering of the sand by-pass pipe is likely to remove this diving attraction. However the diving quality of the training walls has the potential to increase with the possible stabilization of the training walls with additional rock combined with lower tidal velocities.
5.6 Commercial Activities
Current commercial activities on the Broadwater include:
• offshore fishing charters;
• self-drive and skippered house boats, yachts, dinghies, personal watercraft and pontoon boats;
• paraflyers;
• harbour sized cruise vessels;
• jet boats; and
• amphibious vehicles.
The “Gold Coast Waterways Commercial Operator Demand Study” states the waterways provide a hub of marine activities attracting an estimated 483,000 visitors each year, accounting for 4.35% of all Gold Coast visitors. This study focused on ‘tourism associated’ vessels and stated that there are 360 ‘tourism’ associated vessels on the Gold Coast. The study concludes that 70% of vessels had a draft of less than 1m, 70% of trips were taken on a weekday, and 70% of operations were during daylight hours.
Commercial activities are likely to be effected to various levels by the temporary closure of the Seaway and South Channel during the dredging works and cruise ships navigation. However, these commercial activities are all likely day tours that could be offered to cruise ship passengers. Dredging of the Seaway and South Channel are not likely to improve the navigable areas of most of the commercial vessels due to their shallow draft.
Department of State Development, Infrastructure and Planning, Queensland Government
The Draft Environmental Impact Statement (EIS) prepared by GHD in 2006 identified potential impacts, opportunities and recommendations based on a specified location, preliminary design and construction methodology of the CST. It was informed by legislation, approvals and zoning current at the time and referenced various studies, modelling and preliminary reports that had been undertaken for the CST or considered of relevance.
The EIS identified that the study area contained ecological diversity, areas of nature conservation and valued public land and marine space. There was known presence of federally listed Matters of National Environmental Significance (NES), including threatened and migratory species listed in Table 3 and the Moreton Bay wetland of international importance (RAMSAR wetland) is located within proximity of CST.
Table 3: Significant Fauna and Flora identified in EIS as known or likely to occur
Class Scientific Name Common Name Status
EPBC NCA
Amphibian Crinia tinnula Wallum froglet V
Bird Accipiter novaehollandiae Greg goshawk R
Bird Escacus neglectus Beach stone-curlew M V
Bird Calyptorhynchus lathami Glossy black-cockatoo V
It was determined that the project will impact NES and require referral to federal government as part of the approval process under the Environmental Protection and Biodiversity Conservation Act 1999. Section 9 summarises the likely approval process.
Impacts associated with loss, disturbance or degradation of habitat for communities were discussed, with numerous recommendations provided including progressing or undertaking detailed modelling, targeted studies and surveys. Effects were identified as including capital and maintenance dredging, removal of habitat, closure of public space for accommodating infrastructure and
Department of State Development, Infrastructure and Planning, Queensland Government
introduction and movement of cruise ships. There were several specific impacts identified in the EIS as unable to be mitigated, managed or enhanced. Specifically:
• The removal of valued public open space and the loss of public access to public space considered as unique in terms of environment and location (The Spit); and
• The direct removal and indirect impact on known seagrass communities, the food web and ecosystem.
Due process must be undertaken for the approval referral in accordance with Section 9. A Referral addressing current Terms of Reference will be required for the confirmed CST footprint. Since 2006, numerous targeted studies, ecological investigations and assessments have been undertaken in the area for purposes external to CST such as for Southport Broadwater Parklands and Gold Coast City Council (Regional Infrastructure Project assessment). There are promising potential options for CST in the management of seagrass communities based on outcomes of the Southport Broadwater Parklands recolonisation and translocation programme.
The above information, in addition to current legislation, CST recent modelling and further impact assessment, including Climate Change assessment, would inform the EIS for the selected CST location. A list of technical studies likely to be required, based on our experience on similar referral projects, is contained in Section 9.
There is opportunity to progress the CST project. A considerable amount of work has been undertaken on CST and in the study area. There is a need to update environmental studies based on site footprint to identify impacts, respective significance and viable management, mitigation and enhancement opportunities.
Based on our review of available information and experience on similar referral projects, the feasibility of CST will most likely be influenced by a conditional approval by federal government. At this stage, it is reasonable to expect that conditions associated with biodiversity, monitoring and management programs, public consultation and nature conservation (including offsetting) would need to be pre-empted and financially considered.
5.8 Summary
Dredging works are likely to have both positive and negative impacts on the coastal process of the Broadwater and Seaway. The current modelling by BMT WBM (2013) is only preliminary and only applies to the options considered. It nevertheless provides a good indication of the likely impacts:
• Water levels in the Broadwater (fluvial flood, tides, storm surges) and hence flood risk.
- There would be a small reduction in fluvial flood levels hence a reduction in fluvial flood risk.
- There could however be a small increase in tides (±1 to 4cm) and storm surges levels (-0.1m for coast crossing and +0.1m for coast parallel storms).
Department of State Development, Infrastructure and Planning, Queensland Government
- Effect of sea level rise (0.8m by 2100) has not been studied.
- These could potentially be mitigated by selecting the location with the least impact, balancing of dredging and reclamation works for the overall project.
• Wave conditions in the Broadwater – there could be increase in wave heights such effect is ‘local’ in the Seaway and east of Wavebreak Island. Such localised increment is unlikely to have a significant effect in the Broadwater, although there could be erosion concern on the eastern frontage of Wavebreak Island.
• Current flow – a reduction in the current flow velocities in the Seaway is expected with the channel widening and deepening within the Seaway. Potential impacts on:
- Seaway revetment and breakwater – the reduction in the current flow velocities in the Seaway will help in reducing the scour of the revetment and breakwater. However, from operation point of view it is recommended that the revetment and breakwater are improved to a higher factor of safety against slip failure.
- Existing recycled water release system – the reduction in the current flow velocities between the training walls would likely to reduce the ‘flushing’ capacity of the Seaway slightly. Such reduction may result in the water quality in the Broadwater exceeding the acceptable limit earlier than 2018, although the improved tidal exchange may suggest otherwise, hence requires further investigation. There is also concern about impacts on eddies formation east of Wavebreak Island.
- Planned Ocean Release system – there is a risk of ‘backflow’ of recycled water released in the Ocean back to the Broadwater with the dredging works through the ebb tide delta. Such risk cannot be qualified at this stage as the modelling works of the Ocean release system has been based on the existing ebb tide delta.
- There would be a slight reduction in the wave height at TOS which could be mitigated by placing appropriate quantities of dredged material at an appropriate location north of the channel, to be determined using modelling works.
Depending on the location of the cruise ship terminal, the recreational boating and diving activities in the Broadwater may be adversely affected by the CST. There could also be loss of anchorage areas.
The CST is expected to have positive impacts on the navigation of the commercial boating taking advantage of the deeper and wider channel despite temporary disruptions during the construction and cruise ship navigation. Commercially the cruise ship terminal would attract more business for the commercial boating activities.
There is opportunity to progress the CST project by preparing an Initial Advice Statement (IAS) based on the confirmed site footprint. The project is expected to impact the diverse ecology and valued public space of the area, requiring federal approval under the Environmental Protection and Biodiversity Conservation Act 1999. Feasibility of CST is dependent on comprehensive identification of specific
Department of State Development, Infrastructure and Planning, Queensland Government
impact, scale and management and mitigation options. It is reasonable to expect that conditions will include biodiversity offsets, monitoring and management programs and public consultation.
Department of State Development, Infrastructure and Planning, Queensland Government
This section will comment on AEC (2012)’s cost estimate based on Arup’s experience. The review will focus on the possible risks to the total cost estimate.
The dredging works, berthing structure and terminal buildings constitute approximately 65% of AEC (2012)’s capital cost estimate. Due to the very limited time available, this review has focused on these three elements. No specific contingency allowance has been included in the cost estimates given below.
Berthing and Mooring Structure
AEC (2012) assumed a floating dock system with a most likely cost of $15,572,308. Floating dock systems are typically used at sites with relatively big tidal range to provide safe passenger access at all tides. They would typically have higher maintenance costs compared to a fixed wharf structure. Arup considers that at this early stage of planning it would be more appropriate to assume a fixed suspended deck structure. There would however be opportunity to explore the use of the floating system as the project progresses.
Based on Arup’s experience of similar projects, a suspended deck structure would cost approximately $5000 to $7000/m2. This cost assumes favourable ground conditions and good construction access to allow the wharf to be constructed primarily from land. Arup has assumed that the wharf would be approximately 350m long by 10m wide which results in an indicative cost of $17.5 million to $24.5 million. This cost is slightly higher than the $15.6 million assumed by AEC (2012). It should be noted that the berthing and mooring structure cost can vary significantly depending on the level of service that is agreed.
Capital Dredging
As concluded in Section 4 for costing purposes, the capital dredging volume is 4 million m3 ±1 million m3.
AEC (2012) states that the “most likely’ cost of the capital dredging is $30,796,480. It is understood from the Council that this estimate is inclusive of a mobilisation cost of $2.5 million and based on a unit dredging cost of $6/m3. These cost rates were understood taken from assessment of a recent competitive tender for dredging works in the region. At this early stage of planning, however, Arup would recommend using $10/m3 including mobilisation considering the possible fluctuation in fuel price and currency exchange rates and previous tender prices may reflect the availability and location of the dredger at the time of the tender. Based on a dredging rate of $10/m3, the capital dredging cost will be $40 million ± $10 million, assuming no offshore disposal (i.e. for beneficial re-use on the beach). For business case study, sensitivity test using AEC’s rates is recommended to understand their impact on the business case.
As discussed in Section 4.3, it is likely that indurated sands will be encountered and this will result in a higher dredging cost rate. There is also the need to identify a suitable disposal location, which ideally would be contained within any planned reclamation works within the wider Broadwater Marine project. Based on Arup’s experience from previous studies, the cost of dredging the indurated sands could
Department of State Development, Infrastructure and Planning, Queensland Government
be as high as $25/m3. Based on the 330,000m3 of indurated sands estimated by the 2006 Study, this there is an additional $4,950,000 in the dredging cost.
It is considered that the capital dredging cost is $45 million ± $10 million, including a risk allowance of dredging 330,000m3 of indurated sand.
There is also a risk of this cost increasing further if acid sulphate soils are encountered, at an estimated treatment rate of $50/m3.
Terminal Building
The 2006 study assumed a 2000m2 terminal building. AEC (2012) assumed a 2000m2 terminal building with a ‘most likely’ cost of $7,638,520. This equates to approximately $3,800/m2 which is believed to be appropriate. It is assumed that the customs, quarantine or baggage handling facilities are not required.
Based on the limited time for this review, Arup believes the previous terminal building cost estimates are suitable for the purpose of this feasibility assessment. It should be noted that the terminal building cost can vary significantly depending on the level of service to be provided. It is noted that a higher level of service would most likely make the CST more attractive to cruise ship operators.
Summary
Arup’s cost estimate review has focused on the cost of the dredging, berthing and mooring structure and terminal building as these comprise approximately 65% of AEC (2012)’s capital cost estimate. Arup believes that AEC (2012) have under-estimated the cost of the capital dredging, particularly without the consideration of the risk of encountering indurated sand. It is however noted that it is difficult to ascertain risk of indurated sands and treatment for acid sulphate material until the CST location and navigational requirements are confirmed. Arup believes that AEC (2012)’s estimate for the terminal building cost is appropriate but the estimate for the berthing and mooring structure is on the low side.
6.2 Maintenance Dredging
Dredging work was costed at approximately $10/m3; this figure was used based on the recent dredging program at the Seaway delta which dredged approximately 250,000m3 of sand. Dredged sand was deposited in the near shore zone at Surfers Paradise (beneficial re-use of dredged material). The project was co-funded by the State and the Council with new approvals obtained to dredge the delta and nourish at Surfers. $10/m3 is also in agreement with the average cost maintenance dredging using Trailer Suction Hopper Dredger “Brisbane”.
The 2006 Study assumed an annual dredging amount of 350,000 m3 based on 150,000 m3 in the outer entrance (dredged annually) and 200,000m3 in the swing basin (dredged biannually). AEC (2012) assumed 385,000 m3 per year at a cost of $3,850,000. This equates to a cost of $10/m3 which is in agreement with the cost of the recent dredging program at the Seaway delta.
AEC (2012) states that 60% of the operating cost is in maintenance dredging. As a result, the estimation of the quantity of dredged material is a high risk to the operating cost of the CST.
Department of State Development, Infrastructure and Planning, Queensland Government
Section 4 concluded for costing purposes, the annual maintenance dredging volume of 350,000 m3 ± 50,000 m3 is to be used. Based on $10/m3 this equates to $3.5million/year ± $0.5 million/year.
It is recommended that beneficial re-use of the dredged material be practised in future maintenance dredging works for the CST. It is however noted that this would require further discussion between GCWA and the CST operator on the share of the maintenance dredging costs; and similarly with the Council who would receive the dredged material for beneficial reuse.
Department of State Development, Infrastructure and Planning, Queensland Government
7 Statutory framework and indicative approvals roadmap
The following section describes the statutory framework for the proposed works to develop a cruise ship terminal at the Gold Coast Broadwater, identifies relevant legislation that would need to be addressed and identifies various approvals that may potentially be required from the Commonwealth and Queensland Governments.
7.1 Statutory context
This section provides an overview of the purpose of each piece of major legislation and its relevance to the proposed works, particularly in regard to the agencies that will be involved and approvals that may potentially be triggered.
Table 4 Legislation and project relevance
Legislation Overview
Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act)
The EPBC Act applies to those actions which are likely to have a significant impact on matters of NES. The eight (8) matters of NES protected under the EPBC Act are:
• world heritage properties;
• national heritage places;
• wetlands of international importance (listed under the RAMSAR Convention);
• listed threatened species and ecological communities;
• migratory species protected under international agreements;
• Commonwealth marine areas;
• the Great Barrier Reef Marine Park; and
• nuclear actions (including uranium mines).
State Development and Public Works Organisation Act 1971 (SDPWO Act)
The SDPWO Act establishes the framework for environmental assessment of significant projects in Queensland, identifying the EIS process and its relationship with other Queensland legislation.
A proponent for a project with one or more of the following characteristics may apply to have it declared a ‘significant project’ by the CG under Part 4 of the SDPWO Act:
• complex approval requirements, involving local, state and commonwealth governments;
• potential environmental impacts;
• large capital investment;
• substantial job opportunities;
Department of State Development, Infrastructure and Planning, Queensland Government
• strategically important to the locality, region or state.
Coastal Protection and Management Act 1995 (The Coastal Act)
The Coastal Act provides for the protection, conservation, rehabilitation and management of the Queensland coastal zone, including its resources and biological diversity. The Act has regard to the goal, core objectives and guiding principles of the National Strategy for Ecologically Sustainable Development in the use of the coastal zone.
The provisions set out in this draft State Planning Regulatory Provision (SPRP) are based on the state coastal management plan policies that were in place before the introduction of the SPP. This draft SPRP applies while the full review of the Queensland Coastal Plan is undertaken.
Environmental Protection Act 1994 (EP Act)
The object of the EP Act is to protect Queensland’s environment while allowing development that is consistent with the principles of ecological sustainability. The EP Act acknowledges a general environmental duty of care and does not permit activities that may cause environmental harm unless all reasonable and practical measures have been employed to prevent or minimise such harm.
The following regulations and policies existing under the EP Act are relevant to the proposed works for the cruise shipping development:
• Environmental Protection Regulation 2008;
• Environmental Protection (Air) Policy 2008;
• Environmental Protection (Noise) Policy 2008;
• Environmental Protection (Water) Policy 2009;
• Environmental Protection (Waste Management) Policy 2000; and
The Fisheries Act protects commercial and recreational fisheries resources and their habitats through sustainable use and conservation. Under the Act, disturbance to fish habitats (including the disturbance, removal or destruction of marine plants) is deemed as fisheries development for which approval is required through the IDAS.
Sustainable Planning Act 2009 (SP Act)
The SP Act is Queensland’s principal planning and development legislation. It provides a framework for integrated and coordinated assessment of new development through the IDAS to ensure its effects are managed in a way that is ecologically sustainable. The IDAS provides a common process
Department of State Development, Infrastructure and Planning, Queensland Government
for assessing development which is the subject of other specific legislation, including the Coastal Act, EP Act, Fisheries Act and Heritage Act.
Transport Infrastructure Act 1994 (TI Act)
The TI Act provides a framework for integrated planning and management of an efficient system of transport infrastructure, including port and maritime infrastructure.
The project may require the declaration of the cruise ship terminal as “Strategic Port Land” under the TI Act.
If so, the terminal would be required to develop a land use plan to be adopted in accordance with Section 285 of the TI Act. Future development within this area declared as Strategic Port Land would need to comply with the adopted land use plan.
Aboriginal Cultural Heritage Act 2003 (ACH Act)
Under the ACH Act, Aboriginal and Torres Strait Islander cultural heritage is protected through a duty of care which requires all persons to take reasonable and practical measures to avoid harming such cultural heritage.
Under Division 2 of Part 7 of the ACH Act, a Cultural Heritage Management Plan (CHMP) may be required in the event that a project requires:
• an EIS under another Act (section 87 of the ACH Act); or
• an environmental authority under the EP Act (section 88 of the ACH Act); or
• a development application is made under the SP Act and DEHP is a concurrence agency (section 89 of the ACH Act).
The Native Title Act 1993 (NT Act)
The NT Act provides for the recognition and protection of native rights for Australia‘s indigenous people, as well as providing a legislative approach for dealing with matters of native title. Indigenous rights may exist in areas such as vacant or unallocated crown land, some reserve lands, some types of pastoral lease and waters that are not privately owned. In accordance with the NT Act, a native title process will be required to be undertaken with native title claimants and regulatory agencies over lands for which native title has not been extinguished.
A native title process is required to be undertaken with native title claimants and regulatory agencies over lands for which native title has not been extinguished.
An Indigenous Land Use Agreement (ILUA) may be required, dependent on the outcomes of native title investigations.
Department of State Development, Infrastructure and Planning, Queensland Government
Arup has undertaken a preliminary review of available information on the environmental impact of the proposed Gold Coast Cruise Ship Terminal (GCST). The proposed works will likely have an impact on several matters of National Environmental Significance (NES). An EPBC Protected Matters Search of the study area identifies the following matters of NES that may occur in or may relate to the area:
• Wetlands of International Importance 1
• Threatened Species 49
• Migratory Species 64
Given the number of matters of NES identified within the study area, it is highly likely that the project will constitute a number of ‘controlled actions’ requiring approval under the EPBC Act.
In regard to the process for environmental impact assessment to address the requirements of SEWPC, the most likely process for the preparation and approval of an EIS is that specified under the SDPWO Act. This is an accredited process under the Agreement between the Commonwealth and the State of Queensland under Section 45 of the EPBC Act relating to Environmental Assessment. Initial consideration of the project against the criteria specified in Part 4 of the SDPWO Act determines that it is highly likely to be considered a ‘significant project’ requiring an EIS in accordance with Section 26 of the SDPWO Act.
This section outlines recommendations for a number of further investigations that may be required in preparation for an EIS. This is not an exhaustive list and is based on a preliminary gap analysis against the Terms of Reference for similar projects, the 2006 EIS and prior consultation with Queensland government departments. Key investigations include:
• Hydrodynamic modelling to determine changes to water velocity, salinity levels, bed shear stress and tidal flows for the purposes of identifying changes to erosion or sedimentation rates within the Seaway;
• Dredging study and modelling to determine the likely impacts of proposed dredging activities;
• Water quality modelling;
• Establish a baseline ecological survey to determine; the population of dugongs, turtles, migratory birds and fish that utilise habitats within the area to be disturbed and their tolerance to disturbance from noise, turbidity and boat strikes in particular;
• Establishing the impacts of dredging on seagrass beds and gain an understanding of species reliance on this habitat;
• Benthic surveys of area to be dredged;
• Visual Impact Assessment;
• Determination of Native Title status for all impacted lands (including waterways) and any ILUA requirements;
• Air quality assessment and modelling, particularly targeting sulphur dioxide and nitrogen dioxide;
Department of State Development, Infrastructure and Planning, Queensland Government
• Updated social impact assessment, based on most up-to-date information/options;
• Modelling and assessment of climate change impacts on proposed development;
• Thorough investigation of all land-based and marine dredge material disposal options, including detailed cost and benefits analysis of each option and preferred solution from an environmental, social and economic perspective;
• Detailed investigation of impacts on fisheries habitat, seagrass communities and ecosystem value and identification of potential offset arrangements (like for like);
• Modelling of noise and vibration impacts due to construction and operation of the proposed CST;
• Detailed assessment of potential impacts within or adjacent to Moreton Bay Marine Park (MBMP) and RAMSAR wetland area;
7.2.1 Summary of key potential impacts
The key potential impact of works have been summarised below:
• Degradation of water quality, reduced visibility and reduction in marine life as a result of dredging and disposal;
• Reduction in marine species, namely dugongs, fish and turtle species as a result of removal/damage to seagrass beds;
• Reduction in nursery habitat for juvenile fish and areas that support migratory birds species as a result of interference with Seaway rock wall and intertidal sand flats;
• Reduction in the amount and diversity of benthic organisms;
• Impact on the amenity of the Gold Coast Broadwater
It is highly likely that an Environmental Impact Assessment will be required for works as well as referral under the EPBC Act. Should the project progress; the next step would be to undertake further environmental investigations and seek approval for the project to be declared a ‘Significant Project’ under the SDPWO Act. The project would also require ongoing monitoring and management during the construction and throughout the operation of the port facility. An Environmental Management Plan (EMP) would be required, outlining these environmental monitoring and management obligations.
7.3 Potential approvals required
The marine and land-based works required to facilitate the cruise shipping operations in the Gold Coast area will trigger the requirement for various approvals under Commonwealth and Queensland legislation. Key to achieving such approvals will be the need for significant technical assessment of the proposal in relation to its potential impacts upon the environment, social and economic factors and identification of relevant and appropriate means to mitigate the effects of such impacts.
Department of State Development, Infrastructure and Planning, Queensland Government
Although this report identifies potential approvals for the construction and operation of the cruise ship terminal, the recommendations are based on the interpretation of available materials and information provided. This report does not purport to provide a legal opinion on the applicability of specific legislation and the triggering of associated approvals.
Department of State Development, Infrastructure and Planning, Queensland Government
Whole of project – declared a ‘significant project’ involving matters of ‘national environmental significance’
Environmental Protection and
Biodiversity Conservation Act 1999 (EPBC Act)
AND
State Development
and Public Works
Organisation Act
1971 (SDPWO
Act)
Preparation and approval of an EIS is that specified under the SDPWO Act, which is an accredited process under the agreement between the Commonwealth and the State of Queensland under Section 45 of the EPBC Act.
Coordinator General
AND
Minister for Sustainability, Environment, Water, Population and Communities
The likely timeframe for the preparation and approval of an EIS of this nature is anticipated to be no more than two years.
This does not
include
subsequent
approvals
identified as
requirements in
the EIS and may
vary on the
timeframes
required for
detailed
investigations.
Works over lands for which native title has not been extinguished.
The Native Title Act 1993 (NT Act)
A native title process will be required to be undertaken with native title claimants and regulatory agencies over lands for which native title has not been extinguished.
An Indigenous Land Use Agreement (ILUA) may be required, dependent on the outcomes of further native title investigations.
Commonwealth Attorney-General,
The National Native Title Tribunal,
Native Title Representative Bodies
Potentially 12 months if an ILUA is required
Works on or adjacent to a place of Aboriginal cultural heritage significance
OR
In the event that the project requires an EIS.
Aboriginal Cultural Heritage Act 2003 (ACH Act)
The preparation of a CHMP with relevant Aboriginal Parties under the ACH Act.
The duty of care provisions requires all persons to take reasonable and practical measures to avoid harming such cultural heritage.
Department of Aboriginal and Torres Strait Islander and Multicultural Affairs (DATSIMA)
N/A
Department of State Development, Infrastructure and Planning, Queensland Government
Works on or adjacent to an item identified on the Queensland Heritage Register
Queensland Heritage Act 1992
Development Permit for works on or adjacent to an item identified on the Queensland Heritage Register
Department of Environment and Heritage Protection
3 - 6 months
Dredging works
Environmental Protection Act 1994 (EP Act)
Development Permit for an Environmentally Relevant Activity ERA16 Extractive and Screening Activities (Dredging) and Registration Certificate
Department of Environment and Heritage Protection
3 - 6 months
Removal of quarry materials from tidal waters
Coastal Protection and Management Act 1995 (Coastal Act)
Allocation of Quarry Material or Dredge Management Plan (if other than marine disposal of dredge material is proposed)
Department of Environment and Heritage Protection
3 - 6 months
Dredging works in tidal waters
Coastal Protection and Management Act 1995(Coastal Act)
Development Permit for Operational Works (that are tidal works for capital dredging)
Department of Environment and Heritage Protection
3 - 6 months
*Disposal of dredge material from capital dredging in tidal water
Coastal
Protection and Management Act 1995 (Coastal Act)
Development Permit for Operational Works (that that is within a coastal management district)
Department of Environment and Heritage Protection
3 - 6 months
*Disposal of dredge material from capital dredging within a declared fish habitat area
Fisheries Act 1994 (Fisheries Act)
Development Permit for Operational Works (that that is completely or partly within a declared fish habitat area).
Department of Agriculture, Fisheries and Forestry (DAFF)
3 - 6 months
Destruction of marine plants found within the dredge footprint area or at or adjacent to the proposed wharf structure
Fisheries Act 1994(Fisheries Act)
Development Permit for Operational Works (that that is the removal, destruction or damage of a marine plant) – if marine plants are found in the dredge footprint or at or adjacent to the proposed dredge material ground
Department of Agriculture, Fisheries and Forestry (DAFF)
3 - 6 months
Constructing Fisheries Act Development Department of 3 - 6 months
Department of State Development, Infrastructure and Planning, Queensland Government
Act, requiring a land use plan to be adopted in accordance with Section 285 of the TI Act.
*The type of statutory approvals required for the disposal of material from the capital dredging will vary depending on the location of disposal determined as the most appropriate.
The following diagram provides an illustration of the project approvals process requiring a comprehensive assessment of environmental, social and economic factors through an EIS.
Department of State Development, Infrastructure and Planning, Queensland Government
8 Information to be Provided by Short-listed Proponents
At this stage, it is expected that the short-listed proponents would not have sufficient time to undertake sufficient technical studies to address the impacts. It is considered that realistically the returnable would be:
• Demonstration of appreciation of the complexity of the estuarine and coastal processes and potential impacts of the CST.
• Demonstration of the capability and resource to understand these impacts and propose mitigation measures
• Demonstration of the capability and resource to undertake Environmental Impact Assessment
• Financial allowance for the risks associated with the impacts and the corresponding mitigation measures
Peer Review of GCCC Simulation Report of 6 Dec. 2012
Background Meridian Maritime Services conducted an investigation into the feasibility of piloting large cruise ships to and from a proposed terminal within the Gold Coast Broadwater. The study was enabled by constructing a port model and using the Smartship Australia facility in Brisbane.
The Simulation Report was preceded by a Simulation Plan for the exercise and this report uses both to review the outcomes.
The simulation was conducted using current practicing and licensed port pilots.
The review used only the reports of the study referred above without benefit of personal observation during the conduct of the study.
The Report The report was well laid out and covered most areas thoroughly.
There were some abbreviations used which were not explained and some stated values which were not justified in the references.
Channel Design. Under Section 5 Operational Considerations there were a number of unexplained differences to the references concerning PIANC calculations in Appendix 4. The first was located under Section 5.1 The Approach Channel on page 6 of the Report. Under the first dot point at the end of that subsection was the reference to PIANC beam multiplier of 3.8. In Appendix 4 the calculation for this area is shown correctly as 4.3. Similarly each of the succeeding references to the PIANC calculations in Appendix 4 the report understates the values by at least 0.5 and up to 0.63..
The report includes at Appendix 1, the Screen Plots and Evaluation Sheets for the 63 manoeuvres which were simulated. The vast majority of the runs did not comply with the stated objective of staying one beam width clear of the dredged cut toe-line and there were many uncompleted runs where groundings occurred.
The Swing Basin dimensions of 500 m proved inadequate in size on a number of runs and a future simulation should model more space for the high speed approaches required for large vessels to stop and turn. A more conservative approach would have the basin at twice the maximum length of the design ship for the port.
A major value of simulation is that the models can be used to illustrate that change to either the operation or geography is required. The simulation certainly was valuable in determining that the South Channel required considerable expansion in its width.
It was unfortunate that a couple of instances of large alterations of heading (“Queen Victoria” outbound at the entrance to the Seaway or “Regal Princess” grounding whilst exiting the Approach Channel) were unremarked in the commentary or Conclusions and Recommendations. These incidents illustrated the severe limitations of an Approach Channel only 140 m in width for vessels exposed to strong beam-on conditions.
Those incidents and the PIANC data for the larger vessels lead the writer to the conclusion that despite many successful passages through the Approach Channel it is too narrow for all occasions. The report did conclude that the derived width used of 140 m for the Approach Channel was the minimum required. This is no ordinary set of circumstances creating a channel through a sand delta. With the prevailing conditions being beam on in most instances the PIANC guidelines as used for the report are relevant. When considering Bank Effect the report (Appendix 4) uses “sloping channel edges and shoals” whereas “steep and hard embankments” would be more appropriate which would add extra width to the channel which in the writer’s opinion should be more like 160 metres wide. Even on the basis used by the report the Emerald Princess of 36.05 metre beam requires a channel width on Approach of 155.02 m beam which is illustrated in Appendix 4, and 165.98 metres for Voyager of the Seas of 38.6 m beam. Both of these vessels were used extensively in the simulations reported.
It should be stated that the PIANC document referred above is titled Approach Channels a Guideline for Design. The intent of the panel which created the document was that any calculations using their criteria should be proven or otherwise by simulation. However simulation whilst state of the art in the Smartship Australia facility is still based on mathematical models. As such it should be treated with appropriate caution when used in what might be described as unfriendly conditions which can be experienced at the Gold Coast site.
The Bend was said to be constructed for a controlled turn in the simulation model but there was no reference to aids for the pilot to maintain a constant radius turn in order to control the vessel adequately.
Currents. With respect to the currents used in the simulation it was not clear from the report that prior to the use of real time input whether only the currents affecting the South Channel were used through the Bend. Either way the recommendation concerning the South end of Wavebreak Island is valid given the simulation experience.
The recommendation contained under Arrival and Departure Conditions on page 9 of the Report limiting wind conditions to 25 knots (lower limit of a strong wind warning from the Bureau of Meterology) and current levels not exceeding 50% of peak flow values is supported.
Under Keel Clearance (UKC). The UKC were of value and justified the required ukc of 4m. Unfortunately the charts illustrating the values used in Appendix 6 had untitled borders but the text in the report assisted with an understanding of the results produced.
Terminal Options. When options for the terminal sites are considered there should be better truncations to the swing basin than that provided for at Option 3 for the simulation. It should be possible for a truncation to provide for a vessel to set up to head for the centre of the swing basin without forcing the stern of the vessel close to the toe-line in order to enter the basin.
The berth pocket is too tight at 50 m width for modern passenger vessels some of which are now up to 44 m beam. A pocket of 80 m width would be more appropriate.
The terminal on the Spit was referred in the Evaluation Sheets (Appendix 1) to as alternately FMB1 or FMB2 without explanation of the abbreviations.
Conclusion The report illustrates that this study was very much a first concept simulation despite the earlier more limited 2006 effort by GHD for the Coordinator General.
More consideration of appropriate channel and bend widths is required with design engineers and pilots working together to achieve a safe and reliable arrangement.
The Harbour Master should be consulted in the planning for a future simulation to ensure that operations will be conducted and navigation aids provided with the necessary approvals under the Transport Operations Marine Safety Act 1994.
