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

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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         Maximum            Range
                                                              (m MSL*)        (m MSL*)            (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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