Noosa Spit SEMP Final Report

Noosa Spit SEMP Final Report 103 References

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6 References Barnes, M.P., Visser, J. and Fisk, G. (2017). Implementation of Trigger-Based Coastal Management Strategies, Coasts & Ports 2017 Conference.

Collins (1972). Prediction of shallow-water spectra, Journal of Geophysical Research, Volume 7, Issue 15, Oceans and Atmosphere, 2693 – 2707.

Geoscience Australia (2017). High-resolution depth model for the Great Barrier Reef, Beaman R.J.

Fisk, G. & Kay, R. (2010). Dealing with uncertainty in climate change adaptation planning and developing triggers for future action, Practical Responses to Climate Change Conference 2010, Melbourne, September 2010.

Commonwealth Government (2015). EPBC Act Policy Statement 3.21 – Industry guidelines for avoiding, assessing and mitigating impacts on EPBC Act listed migratory shorebird species. Commonwealth Department of the Environment, Canberra, Australia.

ICM (2010a). Option Review Noosa River Spit, prepared for Sunshine Coast Regional Council.

ICM (2010b). Noosa River Spit Erosion Protection Works Drawing Register, 23 November 2010, prepared for Sunshine Coast Regional Council.

MSQ (2019). Queensland Tide Tables 2017. Maritime Safety Queensland.

O’Brien, M. P. (1969) Equilibrium Flow Areas in Inlets on Sandy Coasts. Journal of the Waterways and Harbours Division. ASCE No. WW1, pp.43-52.

Queensland Government (2012). Queensland coastal risk and bathymetric LiDAR: a pilot study for collecting near-shore bathymetry. Queensland Department of Science, Information Technology, Innovation and the Arts, Brisbane, Australia.

Saha, S., and Coauthors (2010). The NCEP Climate Forecast System Reanalysis. Bull. Amer.

Meteor. Soc., 91, 1015-1057.

Saha, S., and Coauthors (2014). The NCEP Climate Forecast System Version 2. J. of Climate, 27(6), 2185-2208.

Tomlinson and Chamberlain (2006). Noosa River Entrance Channel Dynamics, Griffith University, CRC for Coastal Zone, Estuary and Waterway Management, 1 – 75.

van Rijn, L.C., D.J.R. Walstra and M. van Ormondt (2004). Description of TRANSPOR2004 and Implementation in Delft3D-ONLINE. Z3748.10 – report prepared by Delft Hydraulics for DG Rijkswaterstaat.

WMA Water (2017). Noosa River Flood Study Upgrade, prepared for Noosa Shire Council, March 2017.

WRL (2014). Riverbank Vulnerability Assessment using a Decision Support System: Clarence River (Rogans Bridge to Ulmarra), WRL Technical Report 2014/12 December 2014.

Noosa Spit SEMP Final Report A-1 Metocean Data Collection


Appendix A Metocean Data Collection

G:\Admin\B23636.g.mpb.NoosaSpit_SEMP\M.B23636.002.MetoceanDeployment.docx

Technical Memorandum

From: Matthew Barnes To: Noosa Shire Council Daniel Wishaw

Date: 29 March 2019 CC:

Subject: Noosa Spit SEMP - Lower Noosa River Metocean Data Collection

1 Instrument Deployment Summary To inform the Noosa Spit SEMP, metocean data collection has commenced including:

• The deployment of six tide recorders in the lower Noosa River to continuously measure water level for approximately six weeks. This data will be used to calibrate the hydrodynamic model and may also provide some valuable information to partially address concerns regarding the published tidal planes.

• Offshore fixed deployment Acoustic Doppler Current Profiler (ADCP) to continuously measure water level, current speed, current direction and wave parameters (height, period and direction). This data will be used to calibrate both the hydrodynamic and wave models.

• Boat-mounted ADCP measurements have been collected during both neap and spring tidal conditions. The measurements (from approximately low water to low water) were taken at Dog Beach, Noosa Sound, Munna Point and Noosaville. This data will used to calibrate the hydrodynamic model and understand the peak flood and ebb tide currents occurring at Dog Beach.

Figure 1-1 provides a map showing the instrument deployment and boat-mounted ADCP cross-sectional transect locations. Table 1-1 provides a summary of the instruments. It is anticipated that the deployed instruments will be retrieved in late April 2019.

Section 2 provides further details on the boat-mounted ADCP measurements

BMT Eastern Australia Pty Ltd Level 8, 200 Creek Street Brisbane Qld 4000 Australia PO Box 203, Spring Hill 4004 Tel: +61 7 3831 6744 Fax: + 61 7 3832 3627 ABN 54 010 830 421 www.bmt.org

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Table 1-1 Instrument Details

Instrument Measurement Deployment Location & Date

Teledyne RDI WorkHorse Sentinel Acoustic Doppler Current Profiler (ADCP) Sea Spider Frame

• Current magnitude and direction (0.5 m bins)

• Wave parameters (height, period, direction)

• Water level

Noosa Main Beach, approximately 8 m water depth (refer Figure 1-1): • Deployment: 10 March 2019

• Retrieval (indicative): 29 April 2019

In-Situ TROLL 500 Pressure Transducer

• Water level Lower Noosa River, 6 locations (refer Figure 1-1)

In-Situ Rugged Baro TROLL

• Atmospheric pressure (used to correct the water level measurement)

Lower Noosa River, 2 locations (refer Figure 1-1): • Deployment: 13 March 2019

• Retrieval (indicative): 29 April 2019

Boat-mounted RDI WorkHorse Sentinel Acoustic Doppler Current Profiler (ADCP)

• Quasi-instantaneous sectional flow (transect)

• Quasi-instantaneous sectional current magnitude and current direction (0.25 m bins)

Lower Noosa River, various locations (refer Figure 1-1): • Neap tide transects: 14 March 2019

• Spring tide transects: 20 & 21 March 2019

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2 Boat-mounted ADCP Transect Summary Acoustic Doppler Current Profilers (ADCPs) measure 3D velocities in a vertical profile of discrete bins at an instant in time (called an ensemble). A boat-mounted ADCP is used to measure velocity profiles while the boat traverses a section or transect. Total flow through the transect is calculated by integrating the ADCP velocity profile data vertically from the bottom-most to the top-most bin and horizontally/temporally across each transect using the Teledyne RD Instrument WinRiver II software.

A total of 288 unique transects were completed during neap tide and spring tide periods in the lower Noosa River. The transect locations are shown in Figure 2-1 and include:

• Neap tide cross-sectional transects at Dog Beach, Noosa Sound, Munna Point and Noosaville on 14 March 2019

• Spring tide cross-sectional transects at Dog Beach, Noosa Sound, Munna Point and Noosaville on 20 March 2019

• Spring tide long-sectional transects at Dog Beach on 21 March 2019

Figure 2-1 ADCP Transect Locations

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Example processing of a flood tide and ebb tide cross-sectional transect at Noosaville is shown in Figure 2-2 and Figure 2-3.

The right panel of the WinRiver II interface provides a summary of the measurement including:

• Total Q (flow, m3/s) which is the sum of the ‘Measured Q’, ‘Top Q’ and Bottom Q. The ‘Top Q’ and ‘Bottom Q’ are estimates of the flow components not directly measured by the ADCP due to instrument blind spots at the top and bottom of the water column. Similarly, the WinRiver II software estimates the ‘Left Q’ and ‘Right Q’ which correspond to the flow components at the left and right riverbanks that cannot be directly measured with the boat-mounted instrument.

• The width (m) of the transect and the cross-sectional area (m2) and estimates of the cross-sectional flow speed (m/s)

The ‘Stick Ship Track’ illustrates the transect and the magnitude and direction of the flow. The ‘sticks’ pointing upstream in Figure 2-2 indicate flood tide conditions. The ‘sticks’ pointing downstream in Figure 2-3 indicate ebb tide conditions.

The cross-sectional plot at the bottom of the WinRiver II interface shows the vertical bins at an instant in time (the instantaneous ensemble) as the boat-mounted instrument is towed across from the right to left riverbank (or vice versa). Together, the combined bins provide a quasi-instantaneous snapshot of the cross-sectional flow velocity. This data is the basis for calculating the ‘Measured Q’.

Timeseries plots of the quasi-instantaneous ‘Measured Q’ at Dog Beach, Noosa Sound, Munna Point and Noosaville are provided in Figure 2-4 and Figure 2-5. For reference, the indicative water level at Munna Point is also shown on the plots (based on Maritime Safety Queensland predations and published tidal planes). In tidal estuaries and at a given location, the peak flood or ebb flow rates will coincide with the transition from high to low water (or vice versa). The flow rate will be close to zero at times of peak high or low water level (commonly referred to as ‘slack water’).

The cross-sectional ‘Measured Q’ and ‘Total Q’ collected with the boat-mounted ADCP will provide important data for calibrating the hydrodynamic model developed for the SEMP. The data will be used to validate the volume of water in the estuary between high and low tide.

The measured cross- and long-sectional flow velocity and direction will also be used for model calibration/validation purposes. The long-sections will also provide important information on the peak spring tide currents at Dog Beach.

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Figure 2-2 Example Flood Tide ADCP Transect Measurement at the Upstream (Noosaville) Location

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Figure 2-3 Example Ebb Tide ADCP Transect Measurement at the Upstream (Noosaville) Location

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Figure 2-4 Measured Q at Dog Beach (top) and Noosa Sound (bottom)

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Figure 2-5 Measured Q at Munna Point (top) and Noosaville (bottom)

G:\Admin\B23636.g.mpb.NoosaSpit_SEMP\M.B23636.003.MetoceanRetrieval.docx

Technical Memorandum

From: Matthew Barnes To: Noosa Shire Council Daniel Wishaw

Date: 31 May 2019 CC:

Subject: Noosa Spit SEMP - Lower Noosa River Metocean Data Collection

1 Instrument Retrieval Summary To inform the Noosa Spit SEMP, metocean data collection has been completed. Fixed deployment instruments were retrieved between 28-30 April 2019. This memorandum follows the previous correspondence (M.B23636.002.MetoceanDeployment, 29 March 2019) and includes a summary of the following datasets:

• Tide recorder (pressure transducer) continuous measurements of water level for approximately six weeks at six locations in the lower Noosa River. This data will be used to calibrate the hydrodynamic model and may also provide some valuable information to partially address concerns regarding the published tidal planes.

• Fixed deployment Acoustic Doppler Current Profiler (ADCP) continuous measurements of water level, current speed, current direction and wave parameters (height, period and direction) offshore from Noosa Main Beach. This data will be used to calibrate both the hydrodynamic and wave models.

Figure 1-1 provides a map showing the instrument deployment locations.

BMT Eastern Australia Pty Ltd Level 8, 200 Creek Street Brisbane Qld 4000 Australia PO Box 203, Spring Hill 4004 Tel: +61 7 3831 6744 Fax: + 61 7 3832 3627 ABN 54 010 830 421 www.bmt.org

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2 Fixed Deployment Measurements

2.1 Frames of Reference Units are expressed using the SI (Système International d'unités) convention unless otherwise stated.

Wind and wave direction are expressed as ‘FROM’ the direction of approach and in nautical degrees (degrees relative to true north, positive clockwise).

Current direction is expressed as ‘TO’ the direction of flow and in nautical degrees (degrees relative to true north, positive clockwise).

2.2 Deployment Period Characteristics

2.2.1 Regional Wind Double Island Point Lighthouse weather station (040068, operated by the Bureau of Meteorology) wind roses for the deployment period (10/03/2019 to 30/04/2019) and the long-term average (01/01/1996 to 30/04/2019) are compared in Figure 2-1. The deployment period regional wind characteristics include:

• A predominance of S to SE trade winds;

• A directional spread of winds that is relatively consistent with the long-term average, noting a slightly higher proportion of NNE and SSE winds;

• A lower proportion of 10-minute wind speed exceeding 20 m/s (approximately 39 knots) compared to the long-term average; and

• A higher proportion of 10-minute wind speeds between 10 and 15 m/s (approximately 20 to 30 knots) compared to the long-term average.

Figure 2-1 Double Island Point wind magnitude and direction rose plots: deployment period (left) and long-term average (right)

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2.2.2 Regional Waves Mooloolaba Wave Buoy (operated by the Queensland Department of Environment and Science) wave roses for the deployment period (10/03/2019 to 30/04/2019) and long-term average (01/01/2007 to 30/04/2019) are compared in Figure 2-2. The deployment period regional wave characteristics include:

• A predominance of E to ESE wave conditions;

• A higher proportion of easterly wave conditions compared to the long-term average; and

• A slightly higher proportion of wave heights exceeding 2 m compared to the long-term average.

Figure 2-2 Mooloolaba wave buoy significant wave height and direction rose plots:

deployment period (left) and long-term average (right)

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2.3 Offshore ADCP, Noosa Main Beach Figure 1-1 shows the Noosa Main Beach Offshore ADCP deployment location. The instrument was bottom-mounted at a depth of approximately 9.5 m below AHD.

2.3.1 Currents Recorded current magnitude and direction offshore from Noosa Main Beach and within Laguna Bay are presented as time series and polar plots over the following vertical segments:

• Depth-averaged over the entire water column (Figure 2-3 and Figure 2-4)

• Bottom third of the water column (Figure 2-5 and Figure 2-6)

• Middle third of the water column (Figure 2-7 and Figure 2-8)

• Top third of the water column (Figure 2-9 and Figure 2-10)

The deployment period current characteristics include:

• The depth-averaged currents were typically less than 0.2 m/s except for the final week of deployment which coincided with increased winds. The currents align NE to SW with the ebb and flood phases of the tide and show a weak residual to the SW. The prevailing wave energy is likely to enhance the net SW current direction at this location (refer Section 2.3.2).

• The bottom third of the water column currents were typically less than 0.15 m/s and not strongly influenced by winds. The currents align NE to SW with a very weak residual to the SW.

• The middle third of the water column currents were higher in magnitude and show a stronger residual toward the SW compared to the bottom currents.

• The highest magnitude currents occur in top third of the water column where they are influenced by wind shear at the water surface. The current direction at the surface is more variable due to the wind.

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Figure 2-3 Depth-averaged (entire water column) current magnitude (top) and direction (bottom) time series

Figure 2-4 Depth-averaged (entire water column) current magnitude (m/s) and direction polar scatter plot

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Figure 2-5 Bottom third of water column current magnitude (top) and direction (bottom) time series

Figure 2-6 Bottom third of water column current magnitude (m/s) and direction polar scatter plot

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Figure 2-7 Middle third of water column current magnitude (top) and direction (bottom) time series

Figure 2-8 Middle third of water column current magnitude (m/s) and direction polar scatter plot

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Figure 2-9 Top third of water column current magnitude (top) and direction (bottom) time series

Figure 2-10 Top third of water column current magnitude (m/s) and direction polar scatter plot

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2.3.2 Waves Recorded significant wave height (Hs or Hsig), wave peak period (Tp) and wave direction time series are shown in Figure 2-11. The distribution of significant wave height and direction is also illustrated in Figure 2-12. The Laguna Bay wave climate for the deployment period had the following characteristics:

• Significant wave height typically less than 1.5 m except for the final week of deployment which coincided with increased winds and increased significant wave height close to 2.0 m.

• Wave peak period was typically between 7 and 9 s.

• Due to wave refraction processes at Noosa Headland (Noosa National Park) the dominant wave direction was from the NNE to NE sector. The consistent direction of wave approach is likely to contribute to the observed net SW currents shown in Section 2.3.1.

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Figure 2-11 Recorded significant wave height (top), peak period (middle) and wave direction (bottom)

Figure 2-12 Recorded significant wave height and direction rose plot

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2.4 Tide Recorders, Noosa Main Beach & Lower Noosa River The recorded water level offshore from Noosa Main Beach (Laguna Bay) and within the lower Noosa River time series plots are presented in Figure 2-13 to Figure 2-15. Each plot compares the offshore tidal water level variation with the attenuated condition within the lower Noosa River.

Table 2-1 provides a summary minimum and maximum water level recorded at each location and shows a significant reduction in the tidal range between Laguna Bay and inside the river entrance. According to common tidal range classification, Laguna Bay is mesotidal (tidal range between 2 and 4 m) and the lower Noosa River is microtidal location (tidal range less than 2 m). It is noted that the published astronomic tidal range for Munna Point 1.0 m and Tewantin is 0.89 m and the recordings are generally within this range.

It is noted that Tide Recorder 2 (bottom plot in Figure 2-13) appeared to have been moved on retrieval of the instrument. The raw data suggested that this occurred during the first week of deployment. Data recorded before this time has been discarded.

Table 2-1 Summary of recorded tidal range

Location Minimum (m MSL*)

Maximum (m MSL*)

Range (m)

Noosa Main Beach (Laguna Bay) -1.33 1.53 2.86

Tide Recorder 1 (river mouth) -0.40 0.77 1.17

Tide Recorder 2 (Noosa Sound east) -0.33 0.61 0.94

Tide Recorder 3 (Munna Point) -0.31 0.61 0.92

Tide Recorder 4 (Noosa Yacht Club) -0.29 0.55 0.84

Tide Recorder 5 (Noosa Marina, Tewantin) -0.29 0.56 0.85

Tide Recorder 6 (Tewantin Ferry crossing) -0.27 0.39 0.66 *mean sea level for the instrument deployment period

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Figure 2-13 Recorded Water Level – Tide Recorder 1 (top) and Tide Recorder 2 (bottom)

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Noosa Spit SEMP Final Report B-1 Bathymetric Survey (Acoustic Imagery 2019)


Appendix B Bathymetric Survey (Acoustic Imagery 2019)

Noosa River Survey (Ferry Crossing to Offshore of Entrance)

March 2019

Noosa Council

Assembled by D. Bergersen 26 March 2019

Last Revised: 20 June 2019 Version 1.1

2 Noosa Council - Noosa River Survey 20.06.2019

EXECUTIVE SUMMARY ............................................................................................................3

1.0 INTRODUCTION .............................................................................................................4

2.0 SYSTEM COMPONENTS ...............................................................................................6

2.1 EDGETECH 6205 MULTIPHASE ECHOSOUNDER .....................................................................62.2 APPLANIX POS MV WAVEMASTER .......................................................................................62.3 SONTEK CASTAWAY CTD ....................................................................................................72.4 QPS ACQUISITION, PROCESSING, AND ANALYSIS SOFTWARE ................................................72.5 LAND TRANSECTS AND SINGLE BEAM ECHOSOUNDER ...........................................................8

3.0 GEODETICS AND DATA REDUCTION .........................................................................9

4.0 SYSTEM INSTALLATION AND CALIBRATION ......................................................... 10

4.1 SYSTEM INSTALLATION ..................................................................................................... 104.2 SYSTEM COMMUNICATION AND CALIBRATION ..................................................................... 13

5.0 DATA PROCESSING ................................................................................................... 15

6.0 RESULTS ..................................................................................................................... 17

SURVEY OPERATIONS ............................................................................................................. 17COMPARISON TO EXISTING BATHYMETRY AND FUTURE SURVEYS ............................................. 21BACKSCATTER DATA .............................................................................................................. 22

7.0 SUMMARY ................................................................................................................... 23


Executive Summary Two surveys were conducted for the Noosa Council across a section of the Noosa River extending from the Noosa Ferry crossing to offshore of the Noosa River entrance: a multiphase echo sounder (MPES) swath survey and a single beam echo sounder (SBES) / land transect survey. The latter focussed on shorelines and sand banks around the entrance to the river not surveyed by the swath mapping system. Both surveys were completed without any safety incidents and in a timely manner.

The MPES produced both bathymetry and backscatter (sidescan sonar) data. The emphasis for this survey was the bathymetry data in support of a shoreline erosion study being conducted by coastal engineering consultants. However, the backscatter data were also logged for possible future use in other Noosa Council projects and a small sample of the processed data is presented in this report.

Positioning accuracy (horizontal and vertical) for all survey data were 1-2cm, with all data reduced to AHD. Approximately 2.0 km2 of river area were surveyed with 100% swath coverage, a considerable amount considering the bulk of the river depth is around 2m AHD. The MPES and SBES data were combined and interpolated to produce a composite digital terrain model (DTM) for the entire survey area. A highly detailed view of river and entrance features was obtained, and the swath coverage should assist in the engineering modelling efforts being undertaken by the Noosa Council.

The backscatter data, although not a focus of this report, can be used in the future for such objectives as seabed characterisation and detection of small features on the riverbed or along the river banks (e.g., anthropogenic debris, rocks, soft sediment areas, etc.).

In turn, the combined data set, when imported into a 3D/4D Scene, should provide the Noosa Council with a useful marketing tool to highlight dynamic nature of the river and the complex topography hidden beneath the main water body.


1.0 Introduction Acoustic Imaging Pty Ltd (AI) was contracted by the Noosa Council (NC) to carry out a bathymetry and land survey of the Noosa River extending from the Noosa River Ferry crossing to 500m offshore of the Noosa River entrance. Both surveys will contribute to a Shoreline Erosion Management Plan being developed for the Noosa Spit region by coastal engineering consultants (Figure 1).

The specific survey services requested by NC included:

• A hydrographic survey of the Noosa River and river mouth, and; • A land-based survey of shoreline positions and sand shoals to overlap the

hydrographic survey points.

Figure 1: Regional overview of Noosa River survey.

Three primary surveys were conducted as part of this project.

• An initial multiphase echo sounder (MPES) survey was conducted using the Marine & Earth Sciences (MES) vessel SURVEY1 between March 14-20, 2019. Survey coverage over this period essentially mapped all areas deeper than the 0.5m contour on the prevailing tide.

• A secondary single beam echo sounder (SBES) survey conducted on April 09, 2019 to augment depth information across the sand shoal region of the Noosa River Entrance.

• A selective land survey conducted on April 09 and further infill on May 02, 2019 to capture beach transects, exposed sand shoals in the Entrance region, and foreshore regions around Dog Beach and along Gympie Terrace.


The swath mapping system consisted of:

• Edgetech 6205 Multiphase Echo Sounder (bathymetry and backscatter); • Applanix POS MV Wavemaster (positioning, motion, and heading data); • AML micro-SVS (sound velocity at the sonar head); • SonTek Castaway CTD (sound velocity through the water column); • QPS QINSy software (data acquisition and real-time quality control); • QPS Qimera and Fledermaus (data processing, editing, validation, and presentation); • Chesapeake Technology SonarWiz (backscatter data processing).

An RTK GNSS antenna and Ceeducer single beam echosounder transducer were used for the shallow sand bank and beach/foreshore transects.

This report provides an overview of the results from the Noosa River survey and forms a part of the data deliverables consisting of:

• Ungridded processed data in XYZ Ascii format;

• Digital terrain models (gridded data) in XYZ Ascii format;

• Contours across various survey blocks in the river and offshore;

• Backscatter mosaic of selected representative areas in GeoTiff format;

• Fledermaus Scene containing relevant data sets for further review by NC;

• Daily reports during survey operations to convey progress and any incidents affecting operations; and

• Summary report discussing survey results.


2.1 Edgetech 6205 Multiphase Echosounder The swath mapping sonar used for the survey was an Edgetech 6205 (ET6205) Multiphase Echo Sounder (MPES). The ET6205 produces real-time, high resolution, three dimensional maps of the seafloor whilst providing co-registered simultaneous dual frequency side scan imagery.

For the bathymetry, the ET6205 uses ten receive element transducers and one discrete transmit element. The high number of channels enables superior rejection of multipath effects, reverberation and acoustic noise commonly encountered in the shallow water survey environment. The frequency of the bathymetry channels is 550kHz with an effective “beam” size of 1º x 1º.

Figure 2: Edgetech 6205 transducer head

The sidescan sonar imagery is spread across 4 channels of information: 2 channels at 230kHz and 2 channels at 550kHz. The lower frequency channels provide more information on seabed types whereas the higher frequency channels are better for object / feature detection.

An AML Micro-X Sound Velocity Sensor (SVS) at the head of the sonar provided sound velocity information required for beam steering on a per ping basis. The Micro-X has capabilities for measuring sound velocity ranges from 1375 m/s to 1625 m/s at an accuracy of 0.025 m/s.

2.2 Applanix POS MV Wavemaster The Positioning and Orientation solution for this project was an Applanix POS MV Wavemaster consisting of a small form factor (SFF) POS Control System (PCS) with IP68 water submersible Titanium sealed IMU and a pair of Trimble antennas.

Figure 3: Applanix POS MV Wavemaster components.


The POS MV Wavemaster is a user-friendly, turnkey system designed and built to provide accurate attitude, heading, heave, position, and velocity data. POS MV is proven in all conditions and is the georeferencing and motion compensation solution of choice for hydrographic professionals.

A Fugro Marinestar navigation aiding subscription was activated as part of the Noosa River survey, improving the real-time positioning of the system to less than 10cm horizontally and vertically. The raw positioning and orientation data were post-processed in the Applanix POSPac MMS software package to further improve horizontal and vertical accuracy to less than 5cm.

Roll and Pitch accuracy from the IMU were approximately 0.03°, with Heave accuracy around 5cm. Heading accuracy post-calibration was around 0.1°.

2.3 Sontek Castaway CTD To correct for refraction through the water column a sound velocity probe must be employed during any hydrographic survey. The unit used for this survey was a SonTek CastAway CTD.

Designed for coastal profiling, the CastAway-CTD® incorporates a 6-electrode conductivity cell, coupled with a fast response thermistor to provide highly accurate, high resolution CTD measurements to depths of 100 m. The sound velocity accuracy derived from the CTD is 0.15 m/s. The unit has an in-built GNSS chip that captures the time and location of the CTD profile, and BlueTooth capability for transferring data.

Figure 4: Sontek Castaway CTD.

During acquisition a comparison between the currently loaded SVP and the sound velocity measured at the transducer head was monitored. If differences became too pronounced, then another CTD cast was implemented. In water depths where relevant, a cast was made at a minimum of the start, the middle, and the end of each survey day.

2.4 QPS and Chesapeake Acquisition, Processing, and Analysis Software The QPS QINSy package was used for data acquisition. The software has an excellent reputation for robustness and stability and provided a number of useful online quality control (QC) displays for data monitoring. QINSy logs all raw data in a proprietary DB format, and geospatially corrected data (XYZ solution) in a QPD format. Options exist for exporting a variety of non-proprietary formats.

Figure 5: Typical QC displays offered by QINSy.


Further processing of the data was done in the QPS Qimera and Chesapeake SonarWiz software packages. Qimera was used to correct, clean, and reduce the bathymetry data to the AUSGEOID09 datum, whereas SonarWiz was used to geospatially correct and image enhance the sidescan sonar data into mosaics.

Figure 6: Qimera post-processing software.

All data were combined in Fledermaus to better assess the relationship between the bathymetry and backscatter data, and to QC the results from all survey areas.

2.5 Land Transects and Single Beam Echosounder Ground elevations over the sandbank and beach profiles were acquired using a Leica GNSS GG04 Smart Antenna interfaced to a handheld computer operating Zeno Mobile software for data collection. Real time corrections were received from HxGN Smartnet via a mobile link. The antenna was mounted at a fixed height on a backpack unit with data acquired every second whilst walking over the mapping areas.

Ground elevations over the very shallow water areas were captured from a shallow draft dingy fitted with a 200kHz Ceeducer Ceescope single beam echo sounder (SBES) operating at 6 pings per second. SBES data were acquired with Chesapeake Technology SonarWiz software along with positioning and time stamp information 6 times per second. Vertical accuracy of the single beam transducer at 8 degree beam width is 0.02% of depth or 1cm, whichever is greater. The Leica GNSS GG04 Smart Antenna was located above the transducer at a fixed height and provided elevation of the transducer face to reduce the soundings to datum. Bar checks were undertaken prior to data acquisition and determined a water velocity of 1518 m/s.

All data were reduced to Australian Height Datum (AHD).


3.0 Geodetics and Data Reduction For the Noosa River survey real-time positioning was provided via a direct Fugro Marinestar G4+ tight coupling with the POS MV Primary GNSS antenna and GNSS inertial solution. This aiding solution was at the ITRF2014 Ellipsoid. Transformation parameters to reduce the data to GDA94 were registered within the POSView control software, and further reductions to AUSGEOID09 were implemented in the QINSy logging software. Background to the reduction process is shown in the bullet points below.

• Satellite positioning systems generate positions to the WGS84 datum. WGS84 is the World Geodetic System 1984 and is the main reference for all GPS-based measurement systems.

• Australia uses the GDA94 datum. Differences between WGS84 and GDA94 are small, but become significant for detailed survey operations, and change in time due to the movement of the Australian continent relative to the satellite constellation.

• MGA94 is a Universal Transverse Mercator (UTM) projection of GDA94 geographical coordinates.

• Real Time Kinematic PPP GNSS systems use a geostationary satellite to transmit corrections to the equipped GNSS antenna positioning unit, allowing much higher accuracy for positioning, generally to sub 15cm level.

• AUSGeoid09 is a geodetic model maintained online by the Australian Government Dept. of Resources, Energy and Tourism. This model describes the relationship between the ellipsoidal height (GDA94) and the orthometric height in AHD.

Following acquisition, the POS MV data were post-processed using the Trimble CentrePoint RTX service to improve the accuracy of the ellipsoid-referenced height in GDA94. Trimble RTX leverages real-time satellite and atmospheric data from a global network of tracking stations, along with highly accurate models and algorithms to generate Trimble RTX corrections. These corrections were used to provide 1-2 cm accuracy for the georeferencing of the dataset to AHD.

AHD is the vertical datum requested by NC. Employing the method above ensures that both high accuracy bathymetry and on-shore NC data are referenced to AHD. Spot checks of AHD conformance with the new swath data were conducted by comparing contours derived from the new data to previous charts created across the survey region (selecting those areas least likely to have experienced any erosional or depositional changes). An example image is shown in the figure below.

Figure 7: Alignment of chart contours with 2019 swath bathymetry contours.


4.0 System Installation and Calibration

4.1 System Installation Installation of the swath mapping system on the MES vessel SURVEY 1 occurred on March 14, 2019. The AI Universal Sonar Mount (USM) Expedition mount was attached to the starboard side of the SURVEY1. A permanent mounting plate is affixed to the gunnel of the SURVEY1 and the USM hinge mount bolts on to the plate. A vertical Z-Pole is attached to the hinge mount, and the ET6205 transducer attaches to it.

An antenna mast with GNSS spreader bar attaches to the back side of the hinge mount, and a plate for the POS MV IMU attaches to the front side. Thus all MPES components are affixed relative to the mount and not the vessel.

Figure 8: ET6205 mounted on starboard side of SURVEY1.

The Z-Pole pivots around the USM X-Pole and hence be raised out of the water during vessel transits. Deployment of the transducer into a vertical / survey configuration was done in a very controlled manner through a combination of purpose-built large wrench attached to the rotation mechanism on the hinge mount and a rope attached near the base of the pole. Recovery of the pole into a horizontal position was done in a similar manner.


In the deployed state, further support for the transducer and pole was provide by a wood block inserted between the Z-Pole and the vessel hull, and a ratchet strap extended around the lower part of the Z-Pole and then tightened to secure all components to the vessel.

Figure 9: Deployment and securing of Edgetech 6205 on pole to vessel.


The two Trimble 540AP GNSS antennas associated with the POS MV were affixed to a pair bolts at the ends of the spreader bar. The location of the mast / mount provided clear views of all available GNSS satellites. Separation between the two antennas is mechanically designed to be 2m but a refined measurement was derived from the GNSS Azimuthal Measurement System (GAMS) calibration (see Calibration section below)..

Figure 10: GNSS antenna mounting on an L-shaped bracket at the stern of the vessel.

The POS MV PCS and all other electrical equipment were housed in the bow section of the main cabin. GNSS antenna and IMU cables were fed into the area along the starboard side of the deck and excess cable neatly coiled within the space to minimise the risk of trips/slips/damage to the cables.

The acquisition laptop was located on a shelf in front of the passenger seat on the port side of the vessel. An external monitor was connected to the laptop to provide the helmsman with display of the real-time DTM to assist in vessel steerage.


4.2 System Communication and Calibration After the POS MV system was installed and all cables connected, basic system communication tests were conducted to ensure that all sensors composing the POS MV were receiving or sending data. This included checking whether the Marinestar navigation aiding solution was being received.

The figure below shows an example of Marinestar reception in POSView, the online interface associated with the POS MV. Fields within the User Interface (UI) were monitored for changing values and reception of the Marinestar signal is shown in the Nav Status field.

Figure 11: POS MV Communication and Integration Tests – Marinestar integration received successful, IMU, PGNSS and SGNSS received successfully.

Communication between the POS MV and the ET6205 TPU were also tested.

The heading solution for the system was already established from previous work with this vessel and mount system. The POS MV heading solution (and associated vector between antennas) is called a GNSS Azimuth Measurement System (GAMS). The final values derived are as follows: X = 0.022m, Y = -2.005m, and Z = 0.008m.

Another vector derived from the data is the Primary GNSS antenna to the survey Reference Point (selected as the target on top of the IMU). This vector was manually measured but further refinement was possible through analysing the POS MV data acquired during the various survey days. The final values derived are as follows: X = -0.220m, Y = 1.034m, and Z = -0.971m.

Finally, a combination of physical measurements and design drawings for the USM mount were used to derive a final lever arm vector for the Reference Point to the Acoustic Centre of the ET6205. This vector is required to provide proper motion compensation and positioning for the MPES data. The final values derived are as follows: X = -0.063m, Y = 0.401m, and Z = 1.764m.


Calibration of the ET6205 transducer mounting relative the vessel reference frame was achieved through a Patch Test conducted during the system trials with MES on the Brisbane River. A spot check for the Roll bias was conducted from the offshore area of the Noosa River survey. The final bias values for the sonar are shown in the figures below.

Figure 12: Bias values and lever arms used during processing for the Edgetech 6205 Port transducer.

Figure 13: Bias values and lever arms used during processing for the Edgetech 6205 Starboard transducer.


5.0 Data Processing The bathymetry data were processed in the QPS Qimera package using the following workflow:

• Load logged DB files;

• Convert raw Range/Theta data to a geospatially corrected (XYZ) solution resulting in the creation of QPD files;

• Generate a Dynamic Surface;

• Load and apply processed positioning and orientation data from the Applanix POSPAC MMS software;

• Load and apply any extra SVP files from the Sontek Castaway CTD;

• Apply a weak Spline Filter to flag anomalous soundings as REJECTED;

• Manually clean (REJECT) any soundings deemed inconsistent with the river bed / sea bed or associated features that may be a hazard to navigation;

• Check Shallow and Deep Surfaces for any remaining anomalous soundings;

• Grid data at 0.5m and 1m bin sizes using a Weighted Moving Average algorithm with a Weight Diameter of 3.

• Export data products in a variety of formats.

Some minor modifications to this general workflow were implemented for selected lines and areas (e.g., differing levels of Spline filtering or Beam Number filtering).

The single beam echo sounder (SBES) and land transect data were manually processed to remove anomalous data spikes and then reduced to AHD. A comparison between SBES data and the gridded swath bathymetry data was conducted prior to interpolation to allow extraction of contours across the sand shoals inside the Noosa River entrance. Mean and median differences between the two data sets was <10cm and deemed acceptable for the survey objectives.

Figure 14: Results of cross check comparison between SBES point data and gridded swath bathymetry data.


Selected lines sidescan sonar data were processed in the Chesapeake Technology SonarWiz package using the following workflow:

• Load XTF files as exported from QINSy;

• Check real-time bottom tracking (for slant range correction of imagery) and if necessary re-track using automated or manual techniques;

• Build Empirical Gain Normalisation (EGN) curves for main lines of each block. Apply EGN to files for image enhancement;

• If necessary, adjust DC gain associated with selected lines to better match image intensity across all lines used to create the mosaic;

• Save final / acceptable mosaic as a gray-scale GeoTiff (palette assigned acoustic shadows as dark pixels and high backscatter returns as light pixels).

Data deliverables included:

• Ungridded, geospatially-corrected, cleaned bathymetry points;

• Gridded, geospatially-corrected, cleaned bathymetry points;

• Contours at 0.5m in DXF format;

• 8-bit backscatter mosaics of selected survey areas;

Although not delivered as part of the initial data set, we intend to assemble and submit a Fledermaus Scene that captures all available data acquired during the survey operations and supplied by Noosa Council as background information. We view this Scene as being potentially useful for illustrating riverbed / seabed features that exist across the Noosa River.


6.0 Results As this project was essentially a data gathering exercise the Results section is limited to observations about the survey operations, internal consistency of new data, comparison to existing bathymetric data, and some brief comments about the backscatter data acquired as part of the survey (and how it might assist future Noosa Council projects).

Survey Operations As a whole the survey operations went well. No equipment failures occurred and all system deployments/recovery were conducted in a safe manner. Afternoon survey operations were interrupted on a couple of days because of thunderstorms but close monitoring of weather fronts via local radar ensured that all personnel were off the water before any danger of lightning strikes occurred.

Tides were not particularly favourable during the survey or the Noosa River was shallower than anticipated / hoped (in terms of clearance of the sonar equipment from the bottom). This resulted in a narrower swath width per survey line and hence more lines required to provide proper infill over the specified areas. Moored vessels also required some deviations and additional infill. However, the area covered over the allocated 5 days of surveying was substantial and I think provides a good baseline for future monitoring efforts.

The figures below highlight some of the features mapped along the river.

Figure 15: River depths at the upstream extent of the survey near the ferry crossing. A shallow sand bar prevented complete mapping along the eastern bank. The hole to the south of ferry crossing is

approximately 7m deep (AHD).


Figure 16: Rocks and sand wave field around the Marina where vessel was moored each evening.

Figure 17: Munna Point Bridge region


Figure 18: Dog Beach region.

Figure 19: Noosa River Entrance region with large offshore sand bank.

Supplementing the swath bathymetry coverage were land transects and a single beam echosounder (SBES) survey conducted over sections of the Noosa River and Entrance that


were too shallow for safe operation of the MPES equipment. The figure below shows the location of these survey points.

across the Noosa River survey region.

Interpolation between these transects combined with the swath bathymetry data allowed the creation of contours map for NC (supplied as a DXF file). All the geospatially-corrected and cleaned data were provided to NC for gridding/interpolation using alternative techniques.

Figure 20: Contours across the Noosa River Entrance region.


Comparison to Existing Bathymetry and Future Surveys Comparison of the 2019 data set to existing bathymetry across the survey area was somewhat limited. The internal check between the 2019 swath bathymetry and 2019 SBES bathymetry showed a mean difference of around 10cm which was deemed acceptable by NC.

The raw 2010 SBES data were not made available for this study but charts showing derived contours were provided as PDFs. Selected sections of these PDFs were converted to Geotif format and imported to a Fledermaus Scene for comparison against the 2019 swath bathymetry. The charts were registered at selected contour heights within the Scene and compared to the contours extracted from the swath bathymetry. In both upstream and downstream locations where presumed minimal erosion or deposition had occurred (e.g., in a protected marina) the two data sets aligned well. As such, our AHD reduction closely matches that used for the 2010 data set.

The 2019 swath bathymetry data set should be an invaluable tool for evaluating future changes in the Noosa River waterway, complimenting existing Lidar data across the region. Alternative techniques to acoustic sonars may be more economically proficient for future large-scale mapping of the river system (e.g., LIDAR systems affixed to drones, Satellite Derived Bathymetry) but the swath techniques employed as part of this survey could be used for more local monitoring of “problem” areas within the river or areas undergoing development.


Backscatter Data Although backscatter data wasn’t a focus of this project the data were logged and selected regions processed to create mosaics. The sidescan-type backscatter data produced by the ET6205 provide finer detail of riverbed features than the bathymetry data, and can be used to make inferences about seabed types (e.g., the bathymetry was gridded at a 50cm bin size whereas the sidescan sonar data was gridded at a 10cm bin size). In general, finer sediments that absorb signal strength appear as darker pixels and coarser sediments that return more signal appear as lighter/brighter pixels.

The example below comes from an area along Hilton Terrace. The sidescan imagery extends to the shoreline and shows a rock-strewn area amongst softer sediments. In this case the mosaic doesn’t show pronounced changes in backscatter strength, but the textural information suggests may be used to show more cemented or consolidated areas relative to soft sediment areas.

Figure 21: Example backscatter mosaic along Gympie Terrace shoreline.

A more extensive analysis of the backscatter data is intended prior to further geophysical work involving a subbottom profiler (SBP) system. The SBP data should allow identification of sand regions in advance of a dredging program.


7.0 Summary The 2019 swath bathymetry and backscatter survey was a success in terms of providing very detailed information about riverbed features within the catchment and the offshore area around the entrance to the Noosa River. The data should assist the current modelling efforts for bank erosion, and future promotional presentations for the general Noosa public.

Although a quantitative assessment of the 2010 SBES survey and the 2019 swath bathymetry survey wasn’t possible, the qualitative comparison between the 2010 charts and 2019 contours looks good. The 2019 contours extracted from the swath bathymetry align nicely with the contours in the 2010 charts in test areas presumed to be free of substantial deposition or erosion.

The backscatter data acquired with the bathymetry data should be useful for future programs planned by the Noosa Council. A small section of the data was presented in this report but more exists across all of the survey area. Possible uses of the data include seabed characterisation (regional and local), identification of features within the river (e.g., debris, rock areas, etc.), and monitoring of slips/slides along the banks of the river.

Although other techniques might be adopted for regional surveying of the river in the future (e.g., drone-based Lidar or Satellite Derived Bathymetry) the acoustically derived data that is a part of this survey provides a highly detailed snapshot in time of the current Noosa River state. As such, it will be invaluable for future monitoring efforts. The detailed imagery should also be of interest to the Noosa public and AI will continue to assist the Noosa Council in generating products that might illustrate the work conducted here.

Noosa Spit SEMP Final Report C-1 Proposed Conceptual Options (PCG 2019)


Appendix C Proposed Conceptual Options (PCG 2019)

Noosa Spit SEMP Options Assessment

<Insert Report Title> Page 1

1. Nourishment Options A: Collection of sediment from the central channel is used to nourish the beach and provide a sand slug to block the southern channel. .


B: Collection of sand from the southern spit is undertaken using a connection to the existing Sand Recycling System and pumped into the erosion zone.


2. River Mouth Control Structures A: Lengthening of the existing spit groyne to increase sediment trapping and decrease sediment bypassing into the river mouth, with a sediment pathway that is more likely to bypass the river mouth entirely due to sediment being mobilised in deeper water.


B: New groyne on the northern side of the river mouth to prevent sand entering the river under seasonal northerly wind and wave conditions, preventing the accumulation of sand that creates the northern spit within the river mouth.


C: Extension of existing control structures to increase the embaymentisation of the Doggie Beach area.


3. Local Structures A: Extension of the submerged structure and additional small groynes along the Dog Beach as per the proposed Stage 2 designed under the works undertaken by the Sunshine Coast Council.


B: Small groyne field to stabilise the beach front.


C: Terminal wall along Dog Beach.

Noosa Spit SEMP Final Report D-1 Risk Assessment


Appendix D Risk Assessment

Current State (Base Case) OPTION 1a: Beach Nourishment: Dual plug and shoreline nourishment. OPTION 1b: Beach Nourishment: Single plug and shoreline nourishment. OPTION 2: Extension of Existing Training Wall OPTION 3: Extension of Existing Submerged Breakwater OPTION 4: Groyne Field OPTION 5: Seawall along Beach OPTION 6: Do Nothing (Accept Impacts)

Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment Risk Description/Treatment

Consequence Medium Consequence Insignificant Consequence Insignificant Consequence Major Consequence Major Consequence Major Consequence Medium Consequence MediumLikelihood Possible Likelihood Rare Likelihood Rare Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible

Risk Rating Medium (M52) Risk Rating Low (L4) Risk Rating Low (L4) Risk Rating High (H72) Risk Rating High (H72) Risk Rating High (H72) Risk Rating Medium (M52) Risk Rating Medium (M52)

Consequence Medium Consequence Insignificant Consequence Insignificant Consequence Medium Consequence Medium Consequence Medium Consequence Medium Consequence MediumLikelihood Unlikley Likelihood Rare Likelihood Rare Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley

ResidualRisk Rating Medium (M48) Residual

Risk Rating Low (L4) ResidualRisk Rating Low (L4) Residual

Risk Rating Medium (M48) ResidualRisk Rating Medium (M48) Residual


Risk Rating Medium (M48)

Consequence Medium Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Medium Consequence Low Consequence Low Consequence MediumLikelihood Likely Likelihood Unlikely Likelihood Unlikely Likelihood Likely Likelihood Likely Likelihood Possible Likelihood Likely Likelihood Likely

Risk Rating High (H56) Risk Rating Low (L8) Risk Rating Low (L8) Risk Rating Low (L16) Risk Rating High (H56) Risk Rating Medium (M32) Risk Rating Medium (M36) Risk Rating High (H56)

Consequence Low Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Medium Consequence Low Consequence Low Consequence MediumLikelihood Possible Likelihood Rare Likelihood Rare Likelihood Unlikley Likelihood Possible Likelihood Unlikley Likelihood Unlikley Likelihood PossibleResidualRisk Rating Medium (M32) Residual


Risk Rating Low (L8) ResidualRisk Rating Medium (M52) Residual


Risk Rating Medium (M52)

Consequence Major Consequence Medium Consequence Medium Consequence Medium Consequence Major Consequence Medium Consequence Medium Consequence MajorLikelihood Likely Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Likely Likelihood Possible Likelihood Likely Likelihood Likely

Risk Rating Extreme (E84) Risk Rating Medium (M52) Risk Rating Medium (M52) Risk Rating Medium (M52) Risk Rating Extreme (E84) Risk Rating Medium (M52) Risk Rating High (H56) Risk Rating Extreme (E84)

Consequence Medium Consequence Insignificant Consequence Low Consequence Low Consequence Major Consequence Low Consequence Medium Consequence MajorLikelihood Possible Likelihood Unlikley Likelihood Possible Likelihood Possible Likelihood Likely Likelihood Possible Likelihood Possible Likelihood Possible



Risk Rating Medium (M32) ResidualRisk Rating Extreme (E84) Residual


Risk Rating High (H72)

Consequence Extreme Consequence Low Consequence Low Consequence Insignificant Consequence Low Consequence Insignificant Consequence Medium Consequence ExtremeLikelihood Possible Likelihood Possible Likelihood Possible Likelihood Rare Likelihood Unlikely Likelihood Rare Likelihood Possible Likelihood Possible

Risk Rating Extreme (E82) Risk Rating Medium (M32) Risk Rating Medium (M32) Risk Rating Low (L4) Risk Rating Low (L24) Risk Rating Low (L4) Risk Rating Medium (M52) Risk Rating Extreme (E82)

Consequence Low Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Low Consequence Insignificant Consequence Insignificant Consequence LowLikelihood Unlikley Likelihood Rare Likelihood Rare Likelihood Rare Likelihood Unlikley Likelihood Rare Likelihood Rare Likelihood Unlikley

ResidualRisk Rating Low (L24) Residual




Risk Rating Low (L24)

Consequence Low Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Medium

Likelihood Likley Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible

Risk Rating Medium (M36) Risk Rating Low (12) Risk Rating Low (12) Risk Rating Low (12) Risk Rating Low (12) Risk Rating Low (12) Risk Rating Low (12) Risk Rating Medium (M52)

Consequence Low Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence Insignificant Consequence LowLikelihood Likley Likelihood Rare Likelihood Rare Likelihood Rare Likelihood Rare Likelihood Rare Likelihood Rare Likelihood Unlikley





Risk Rating Low (L24)

Consequence Major Consequence Low Consequence Low Consequence Low Consequence Low Consequence Low Consequence Medium Consequence MajorLikelihood Almost Certain Likelihood Unlikely Likelihood Unlikely Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Possible Likelihood Almost Certain

Risk Rating Extreme (E88) Risk Rating Low (L24) Risk Rating Low (L24) Risk Rating Medium (M32) Risk Rating Medium (M32) Risk Rating Medium (M32) Risk Rating Medium (M52) Risk Rating Extreme (E88)

Consequence Medium Consequence Low Consequence Low Consequence Low Consequence Low Consequence Low Consequence Low Consequence MediumLikelihood Possible Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Almost CertainResidualRisk Rating Medium (M52) Residual





Consequence Medium Consequence Low Consequence Medium Consequence Low Consequence Low Consequence Low Consequence Medium Consequence MediumLikelihood Almost Certain Likelihood Possible Likelihood Possilbe Likelihood Almost Certain Likelihood Likely Likelihood Likely Likelihood Likely Likelihood Almost Certain

Risk Rating High (H60) Risk Rating Medium (M32) Risk Rating High (H60) Risk Rating Medium (M40) Risk Rating Medium (M36) Risk Rating Medium (M36) Risk Rating High (H56) Risk Rating High (H60)

Consequence Medium Consequence Low Consequence Low Consequence Low Consequence Insignificant Consequence Insignificant Consequence Low Consequence MediumLikelihood Possible Likelihood Unlikley Likelihood Possilbe Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Unlikley Likelihood Almost CertainResidualRisk Rating Medium (M52) Residual





Residual Risk Average Medium (M43) Residual Risk Average Low (13) Residual Risk Average Low (18) Residual Risk Average Low (L21) Residual Risk Average Medium (35) Residual Risk Average Low (L21) Residual Risk Average Low (L25) Residual Risk Average Medium (M49)

Highest Residual Risk in Option Medium (M52) Highest Residual Risk in Option Low (L24) Highest Residual Risk in Option Medium (M32) Highest Residual Risk in Option Medium (M48) Highest Residual Risk in Option Extreme (E84) Highest Residual Risk in Option Medium (M48) Highest Residual Risk in Option Medium (M52) Highest Residual Risk in Option High (H60)

Legend:

Financial

RISK

Cost of mitigation is likely to increase substantially in the event of breakthrough event.

TREATMENT

Implement SEMP; ensure strong project management pirnciples are applied in order to appropriately manage the project costs.

Environmental

RISK

Significant, permenant loss of terrestrial vegetation and wetlands, ongoing and unmitigated erosion will cause loss of habitat. Future mitiagtion options likely to be more extensive and cause greater environmental harm.

TREATMENT

Implement SEMP to reduce environmental harm and damage.

RISK

Litigation from property owners in Noosa Sound due to reduced protection from hazards causing damage to properties.Implementation of a strategy that is not consistent with the State Coastal Management Plan (2016) could present legal/regulatory issues and non-approval from the State.

TREATMENT

Collaborate with relevant stakeholder at government and industry level to ensure regulatory compliance; Undertake SEMP and provide strong messaging of its outcomes to key stakeholder groups, including government and affected industry groups; Seek legal advice, where appropriate to ensure compliance with regulatory and legislative requirements.

Economic

RISK

Loss of use of the area to reducing numbers of person present in the local economy resulting in loss of potential tourism trade.

TREATMENT

Nil

Disruption to recreational area leads to temporary loss in tourist trade.

Stong media messaging about construction of project and disruptions.

Budget estimates undervalue project, resulting in medium financial loss

Early tenderer engagement to refine scope and costs. Strong communication and partnering with the right supplier to ensure time and costs are managed appropriated.

Ongoing nourishment project will cause continual short term impacts on local environmnetal values. Dredge extraction areas can be targeted to avoid environmnetally sensitive areas. Greater spacing between nourishment allows some reduction in impact.

Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations. Careful multi-criteria monitoring to assess and adapt to impacts.

Risk Categories & Management Risk Assessment

Workplace & Public Safety

RISK

Unstable river bank and falling trees could cause injury to staff and public. This may result in an increase in insurance claims for accidents.

TREATMENT

Exclusion of public from affected area using fencing, barriers and signage. Council to hold appropriate insurance coverage for liability and accidents.

Reputational

RISK

Public perception of mismanagment if no action is taken to prevent breakthrough or repair erosion; potential increase in complaints to Council and the media.

TREATMENT

Undertake SEMP; provide strong messaging and communications of SEMP outcomes by Council leaders; include public consultation, where appropriate.

Political

RISK

Political stakeholder intervention from local and/or state government due to breakthrough impacting Noosa Sound properties and boat moorings and due to loss of recreational amenity.

TREATMENT

Strong stakeholder involvement during the planning and decision making process.

Legal, Governance & Regulatory

Risk Assessment

Nil

N/A

Compliants about noisy machinery and the physical appearance of the machinery on the beach, in excess of positive feedback.

Strong media messaging around the project, the tools to be deployed and what this solution provides and avoids. Public consultation to reduce complaints.

Political stakeholder intervention due to the solution requiring expense of public funds for protection of limited area. Individual views on visual or environmental impacts may not align with the option.

Seek supporting 'natural' secondary solution that could alleviate short term concerns and increase overall benefits.

Difficulty in obtaining regulatory approvals, particularly from the Department of Fisheries given ongoing nature of project and possible disruption to adjacent fish habitat zone.

Strong stakeholder engagement with regulatory bodies to assist in defining the detailed design. Strong long-term, multi criteria assessment. Strong compliance reporting to assure stakeholders that habitat zones will not be maintained.




Early tenderer engagement to refine scope and costs.Strong communication and partnering with the right supplier to ensure time and costs are managed appropriated.

Limited short term disruption to local environmental values, limited long term stabilisation of habitat. Nourishment after constrcution likely to casue localised disruption ot environmental values.

Design of structures to incorporate fih habitat zone. Stabilisation of river bank will prevent further loss. Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations.

Risk Assessment

Nil

N/A

Complaints about noisy machinery and the physical appearance of the machinery on the beach, in excess of positive feedback.

Strong media messaging around the project, the tools to be deployed and what this solution provides and avoids. Public consultation to reduce complaints.


Strong stakeholder involvement with the decision making process. Seek public feedback about dredge campaigns.

Difficulty in obtaining regulatory approvals, particularly from the Department of Fisheries given ongoing nature of project and possible disruption to adjacent fish habitat zone.

Strong stakeholder engagement with regulatory bodies to assist in defining the detailed design. Strong long-term, multi criteria assessment. Strong compliance reporting to assure stakeholders that habitat zones will not be maintained.




Early tenderer engagement to refine scope and costs.Strong communication and partnering with the right supplier to ensure time and costs are managed appropriated.

Ongoing nourishment project will cause continual short term impacts on local environmental values. Dredge extraction areas can be targeted to avoid environmentally sensitive areas.

Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations. Careful multi-criteria monitoring to assess and adapt to impacts.

Risk Assessment

Slip Hazard on structure resulting in injury. Introduction of a submerged hazard may result in injuries when diving, swimming or boating near them. This may result in an increase in insurance claims for accidents.

Adequate signage/navigation aids of submerged hazards. Ensure central channel is used for boat traffic.Council to hold appropriate insurance coverage for liability and accidents.

Intial complaints driven by change to navigation of river. Perception of "over management".

Strong media messaging around the decision, upfront messaging about visual aspects during project development, long term spreading of costs. Conduct public consultation, where appropriate.


Strong stakeholder involvement with the decision making process. Seek public feedback about extension of existing structure.

Nil

N/A

Risk Assessment

Submerged structure presents navigation hazard and may be struck by boat, causing serious injury. This may result in an increase in insurance claims for accidents.

Adequate signage/navigation aids of submerged hazards. Council to hold appropriate insurance coverage for liability and accidents.

Complaints about delivering a project that is expected not to work well.

Targetted messaging to align some of the expectations.

Political stakeholder intervention due to the implementation of a 'legacy' design from Sunshine Coast Regional Council that has been shown to be ineffective and expensive.

Nil

Boats damaged by impacting submerged structure may seek recourse. Potential increase in insurance cases and legal disputes.

Adequate signage/navigation aids of submerged hazards. Council to hold appropriate insurance and seek legal advice where needed. Council to seek legal representation for any disputes.






Design of structures to incorporate fih habitat zone. Stabilisation of river bank will prevent further loss. Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations.


Significant, short term disruption to local environmental values, but long term stabilisation of habitat. Nourishment after constrcution likely to casue localised disruption to environmental values.

Design detailing to incoporate habitat reestablishment and stabilise existing habitat. Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations.

Risk Assessment

Slip Hazard on structure resulting in injury. Introduction of a submerged hazard may result in injuries when diving, swimming or boating near them. This may result in an increase in insurance claims for accidents.

Adequate signage/navigation aids of submerged hazards. Council to hold appropriate insurance coverage for liability and accidents.

Intial complaints driven by loss of visual amenity.

Strong media messaging about visual aspect of solution during project development. Conduct public consultation, where appropriate.


Strong stakeholder involvement with the decision making process. Seek public feedback about similar structures at Munna Point and Maroochydore.

Nil

N/A



Budget estimates undervalue project, resulting in medium financial loss.



Design of structures to incorporate fish habitat zone. Stabilisation of river bank will prevent further loss. Nourishment footprint to be carefully selected and programed to avoid most disruptive times and locations.

Perception of "over management" or "too much money being spent" during construction. Public perception that seawall is visually unaesthetic.

Strong media messaging around the decision, upfront messaging about visual aspects during project development, long term spreading of costs. Seawall to be buried.

Political stakeholder intervention due to the solution taking a infrastructure "heavy" direction, large expense of public funds for protection of limited area.

Strong stakeholder involvement with the decision making process. The long term benefits, seeking of public funds, spreading of costs.

Difficulty in obtaining regulatory approvals for a large structure in the coastal zone.

Strong stakeholder involvement with the planning and decision making process. This could include presenting, preparing reports/findings and collaborating with State Government to get regulatory approval.



High up-front capital costs, complex construction in a difficult enviornment leads to financial variation risk.

Loss of value to Noosa Sound properties due to reduced hazard protection/increased boat traffic adjacent to properties. Reduced recreational amenity of the Spit may lead to a drop in user numbers resulting in less tourist trade.

Stong media messaging and economic support to relocate users of Noosa Spit to other local regions.

Cost of mitigation is likely to increase substantially in the event of breakthrough event.

Have a Council budget allocated to in the event of a breakthrough. Apply strong project management skills to manage budget allocation.

Significant, permanent loss of terrestrial vegetation and wetlands, ongoing and unmitigated erosion will cause loss of habitat. Future mitiagtion options likely to be more extensive and cause greater environmental harm.

Nil

Risk Assessment

Trip/slip hazard when exposed. Potentail climbing/play structure that could lead to injuries.

Exclusion of public from area when it is exposed using appropriate barriers and signage. Council to hold appropriate insurance coverage for liability and accidents.

Risk Assessment

Unstable river bank and falling trees could cause injury to staff and public. This may result in an increase in insurance claims for accidents.

Exclusion of public from affected area using fencing, barriers and signage. Council to hold appropriate insurance coverage for liability and accidents.

Public perception of mismanagment if no action is taken to prevent breakthrough or repair erosion; potential ncrease in complaints to Council and the media.

Strong media messaging around the decision and cost/benefits by Council leaders; ; include public consultation, where appropriate.

Political stakeholder intervention from local and/or state government levels due to breakthrough impacting Noosa Sound properties and boat moorings and due to loss of recreational amenity.

Strong stakeholder involvement with the decision making process.

Litigation from property owners in Noosa Sound due to reduced protection from hazards causing damage to properties.Implementation of a strategy that is not consistent with the State Coastal Management Plan (2016) could present legal/regulatory issues and non-approval from the State.

Reduce risk of litigation by making residents aware of risks as per advice from King and Co. (lawyers); Implementation of this strategy is still against regulatory guidance; Collaborate with relevant stakeholder at government and industry level to ensure regulatory compliance;

1

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Newcastle 126 Belford StreetBroadmeadow New South Wales 2292PO Box 266 BroadmeadowNew South Wales 2292AustraliaTel +61 2 4940 8882Fax +61 2 4940 8887Email [email protected]

Adelaide5 Hackney RoadHackney Adelaide South Australia 5069AustraliaTel +61 8 8614 3400Email [email protected]

Northern RiversSuite 5 20 Byron Street Bangalow New South Wales 2479AustraliaTel +61 2 6687 0466Fax +61 2 6687 0422Email [email protected]

SydneySuite G2, 13-15 Smail StreetUltimo Sydney New South Wales 2007AustraliaTel +61 2 8960 7755Fax +61 2 8960 7745 Email [email protected]

Perth Level 420 Parkland RoadOsborne Park Western Australia 6017PO Box 2305 Churchlands Western Australia 6018AustraliaTel +61 8 6163 4900Email [email protected]

LondonZig Zag Building, 70 Victoria StreetWestminsterLondon, SW1E 6SQUKTel +44 (0) 20 8090 1566Email [email protected]

LeedsPlatformNew Station StreetLeeds, LS1 4JBUKTel: +44 (0) 113 328 2366Email [email protected]

Aberdeen11 Bon Accord CrescentAberdeen, AB11 6DEUKTel: +44 (0) 1224 414 200Email [email protected]

Asia Paci�cIndonesia O�cePerkantoran Hijau ArkadiaTower C, P FloorJl: T.B. Simatupang Kav.88Jakarta, 12520Indonesia Tel: +62 21 782 7639Email asiapaci�[email protected]

Alexandria4401 Ford Avenue, Suite 1000Alexandria, VA 22302USATel: +1 703 920 7070Email [email protected]

BMT in Environment Other BMT o�ces

Noosa Spit SEMP Final Report

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