Reference Documents - RAL24/0015

        3. HYDRAULIC MODEL RESULTS
        3.1         Cut-down model results and validation
        Verification results showing that the cut-down developed model accurately reproduces the Noosa Urban model flood behaviour for flood
        levels for the 1% event within the area of interest and a sufficient area upstream and downstream of the study site are included. The results
        demonstrate the model is appropriate for use in the assessment of flood study.


        3.2         Flood Results
        Flood elevations within the site have been extracted from the base case hydraulic model and are provided in Table 3.1. These levels should
        be used as the basis of setting freeboard requirement for the development.

        TABLE 3.1: ESTIMATED FLOOD ELEVATIONS


                                                                                 Flood Elevation
         Frequency
                                                                                 (m AHD)

         1% AEP + CC
                                                                                 2.47

         1% AEP
                                                                                 1.80

         2% AEP
                                                                                 1.60

         5% AEP
                                                                                 1.20

         10% AEP
                                                                                 1.14

        Flow depths in the extent of the proposed works range from 0.1 to 1.1 m in the base case 1% (2100) AEP (defined flood event). As this
        regional of the flood plain acts as a backwater area, flood velocities in relation to the site are very low (max. 0.005 m/s) in the defined flood
        event.

        Mapped outputs of the peak water surface elevation and depth, velocity for the Existing and Proposed Scenarios area provided in Appendix
        C.


        3.3         Impact assessment
        The flood impact objectives adopted for this assessment are outlined in Table 3.2, which suitably demonstrates no off-site impacts.

        TABLE 3.2: FLOOD IMPACT OBJECTIVES


         Aspect of Flooding Impact                                               Objective

         Off-site flood level increase                                           Flood level afflux of less than 0.01 m

         Off-site flood velocity increase                                        Change in flood velocity of less than 0.1 m/s

        Mapping showing the flood level afflux and change in velocity are presented in Appendix C. Key observations are that there are no changes
        to flood elevations or velocity outside the Site as a result of the proposed works.




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               ID: 23148188                                                                                                                            6
Version: 1, Version Date: 30/07/2024