21-0288-FS001-V2_GlenridgeDr_FS-reduced

      Table 4-2: Model Culvert Information
            ID                    Size                      Length       USIL (m AHD)   DSIL (m AHD)
            1         1 x 1800 x 900mm RCBC                   7.00           14.66          14.56
            2               1 x 900mm RCP                    11.15           14.08          14.01
            3               1 x 300mm RCP                    11.17           14.04          13.95
            4               1 x 300mm RCP                    10.74           13.63          13.60
            5               1 x 450mm RCP                    10.78           13.13          13.06
            6               1 x 375mm RCP                    15.00           12.89          12.78
            7               4 x 750mm RCP                    15.00           12.53          12.49
            8          1 x 300 x 450mm RCBC                  11.83           12.77          12.74
            9               1 x 380mm RCP                    13.32           13.40          13.30
           10               1 x 380mm RCP                    11.55           14.60          14.50
           11              10 x 750mm RCP                     11.2           13.95          13.80
           12         3 x 1200 x 900mm RCBC                   11.2           11.94          11.83
           13              1 x 1500mm RCP                     9.79           11.30          11.10
           14               5 x 900mm RCP                     11.2           15.68          15.62
           15               1 x 380mm RCP                    10.99           15.95           15.8
           16              10 x 750mm RCP                     11.2           14.05          13.95
           17               5 x 2400 x 1500                   9.24            6.50           6.40
           18               1 x 450mm RCP                      6.2            8.72           8.68
        Internal             8 x 1200 x 600                  10.00           11.80          11.75



               Model Scenarios
      The Existing (E01) and Proposed (P01) scenarios are described below and depicted in
      Appendix D.

      4.2.1. Existing Scenario (E01)

      In representing the Existing Scenario, the model was setup to represent the overland flow
      characteristics that existed prior to the site being developed. A combination of LiDAR and
      detailed survey was used to represent the existing model terrain. The model was run for the
      63.2%, 39%, 10% and 1% AEP for durations ranging from 30min to 12hrs.

      3.2.3 Proposed Scenario (P02)

      The Proposed Scenario has utilised the Existing Scenario model to represent the proposed
      development. The following changes were made:
           •        Represent internal road at RL12.7m AHD (2d_zsh).
           •        Represent new 8 x 1200 x 600mm RCBC under internal road (1d_nwk).
           •        Represent filling of building envelopes of Lot 1 and 4 to achieve flood immunity
                    (2d_zsh).
           •        Represent minor regrading beside building envelope of Lot 1 (2d_zsh).
           •        Adjustments to roughness to account for new road (2d_mat).
      The model was run for the 63.2%, 39%, 10% and 1% AEP for durations ranging from 60min to
      24hrs.




21-0288-FS001-V2 | Flood Investigation | 60 Glenridge Drive, Cooroibah                                 | 11