2019-12-16 GC Agenda - Item 5 - Attachment 1 - Noosa Spit Shoreline Erosion Management Plan-Part 1

 Noosa Spit SEMP Final Report                                                                           29
 Numerical Modelling of Entrance Configurations




3.4      Sediment Transport (TRANSPOR)
         Modelling of sediment transport has been used as part of establishing the various entrance and
         channel configurations considered as part of the SEMP.

         The TRANSPOR model (van Rijn 2004) has been used to predict sediment transport within TUFLOW
         FV. The TRANSPOR model represents multiple fraction sediment transport including wave- and
         current-related bedload and suspended load dynamics. The calculated bedload component is a
         direct input to the TUFLOW FV morphological bed update scheme, while the suspended load
         component is converted to an equivalent sediment pickup rate (Nielsen 1992), which provides a
         suspended sediment source term to the TUFLOW FV water column advection-dispersion scheme
         (and corresponding sink term to the bed). Suspended sediment settling provides a sink term to the
         water column (and corresponding source term to the bed).

         TRANSPOR represents the interaction of both current- and wave-related sediment transport. The
         presence of waves can enhance sediment pickup and therefore also the rate of transport by the local
         currents. TRANSPOR also includes the prediction of wave-related sediment transport due to
         processes such as wave velocity skewness and wave boundary layer streaming. These (and other)
         processes can generate a net transport in the direction of (or against) wave travel, even in the
         absence of a local current.

         A single sand fraction with median grain size D50 = 0.22 mm will be assumed for sediment transport
         modelling assessments. The internal routines in TRANSPOR are then used to calculate bed
         roughness values based on sediment and hydrodynamic parameters. All other parameters have
         adopted the default values described in van Rijn et al. (2004).

3.5      Numerical Model Calibration & Validation
3.5.1    Targeted Data Collection
         Bathymetric survey and metocean data collection were undertaken to support development of The
         Model, including:

         • High-resolution bathymetric survey of the lower Noosa River and nearshore coastal areas in
           March and April 2019. This work was completed by Acoustic Imaging and is described in
           Appendix B.

         • The deployment of six tide recorders in the lower Noosa River to continuously measure water
           level for approximately six weeks. This data was used to calibrate the hydrodynamic model and
           provides 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 was 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 was used to calibrate the



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