2019-12-16 GC Agenda - Item 5 - Attachment 1 - Noosa Spit Shoreline Erosion Management Plan-Part 2

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).




17                               Noosa Council - Noosa River Survey                          20.06.2019