2020-10-21 Final Order - Approval Conditions and Approved Plans - P&E Appeal No 61 of 2018 - RAL17-0504

                               TABLE A-2    KEY LEVELS

                                Event          Notes                                                         Source          Peak Water
                                                                                                                             Level (mAHD)
                                               Practical minimum level of first floor                                        4.9
                                PMF            Probable Maximum Flood based on Current Climate               Model           3.43
                                               Minimum finished floor level of ground floor                                  2.8
                                               Building pad level                                                            2.6
                                                                                                             Flood
                                1% AEP         2100 climate change conditions                                Information     2.30
                                                                                                             Certificate
                                               20% increase rainfall intensity, 0.8m sea level rise and
                                1% AEP                                                                       Model           2.23
                                               0.8m increase in bathymetry
                                1% AEP         20% increase rainfall intensity and 0.8m sea level rise       Model           2.24
                                1% AEP         Current Climate                                               Model           1.61
                                1% AEP         Typical road level of Lake Weyba Drive                        Survey          1.61
                                               Nominated level to cease evacuation and shelter in place      Survey          1.5
                                               Nominated level to commence site evacuation                   Survey          1.3
                                10% AEP        Nominated level to prepare for site evacuation                Survey          1.1

                               Historic Flooding
                               The historical annual peak heights which have been recorded at the Tewantin gauge are illustrated in Figure
                               A-3. The records indicate that the highest flood level recorded at the Tewantin gauge to date was in 1968,
                               which peaked at 2.0m. Please note that based on other historic events, the within Lake Weyba will have been
                               lower than at the Tewantin Gauge. This event pre-dated the installation of the initial flood warning network
                               which occurred in 1987. The largest event which has occurred since the installation of the flood warning
                               network occurred in February 1992. Events post-1987 have been utilised in the calibration of Noosa Shire
                               Council’s regional hydrological/hydraulic model of the Noosa River system.

                               As discussed previously, there is no flood alert station within Lake Weyba. Therefore, the Noosa Shire
                               Council’s calibrated hydrological/hydraulic model has been used to represent the response of Lake Weyba to
                               regional flooding. Time-series water surface plots of the available alert gauge levels, water levels at the site
                               and modelled rainfall have been provided in Figure . This chart indicates that water levels in Lake Weyba may
                               peak prior to flood peaks occurring at the Tewantin Gauge. The chart also indicates that the February 1992
                               event was characterised with a lengthy period of relatively low intensity rainfall (~10mm/hr) in the lower
                               catchment, however areas of the upper catchment experienced 1 to 2 hours of high intensity (~40mm/hr)
                               rainfall approximately half way through the rainfall event.
5865_R02_V06_Final_FEMP.docx




                               Andres Gabarrin | 27 February 2020
                               135 Lake Weyba Drive, Noosaville
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