Appendix E - Stormwater Management Plan

                           Table 3-8:    Central Basin Stage Storage Discharge Relationship
                          Accumulated
      Stage (m AHD)                         Discharge (m3/s)      Basin Control/ Structure
                          Storage (m3)
     99.6                      0                   0.00           Primary Front & Side Orifices
     99.7                     240                  0.06
     99.8                     491                  0.17
     99.9                     751                  0.33
     100.0                   1,021                 0.53
     100.1                   1,301                 0.77
     100.2                   1,591                 0.87
     100.3                   1,891                 0.96
     100.4                   2,202                 1.04           Primary Outlet Pit Weir Level (RL100.45mAHD)
     100.5                   2,523                 1.21
     100.6                   2,944                 1.66
     100.7                   3,379                 2.01
     100.8                   3,828                 2.06
     100.9                   4,291                 2.12           Major Overflow Weir (Major & Extreme Events)
     101.0                   4,774                 2.83
     101.1                   5,272                 4.15
     101.2                   5,783                 5.95
     101.3                   6,308                 8.16           Minimum Top of Embankment (RL 101.3m AHD)

        Since the Issue A report, stage-storage-discharge relationship for the Central Basin has been updated and
        remodelled. The outlet configuration has not been changed as it is still appropriate and therefore has not been
        modified, however, a slight modification to the width of the overflow weir has changed discharge values.

3.2.6     DEVELOPED MITIGATED PEAKS FLOW RESULTS

Modelling was undertaken for the all recurrence interval storm events up to and including the 1% AEP storm event with
storm durations ranging from 30 to 120 minutes (these were considered the critical durations). A comparison between
peak flows for the existing and developed mitigated scenarios has been provided at each discharge location in Table 3-9
below.

                          Table 3-9:    Developed Mitigated Scenario Peak Flow Comparison
                                         Existing Peak       Developed Peak         Percentage
                       AEP              Discharge (m3/s)     Discharge (m3/s)       Difference
                                                      Discharge Location A (North)
                       63%                    0.17                0.16                  -5%
                       39%                    0.26                0.23                  -8%
                       18%                    0.36                0.34                  -4%
                       10%                    0.43                0.41                  -4%
                       5%                     0.55                0.46                 -17%
                       2%                     0.66                0.59                 -12%
                       1%                     0.77                0.77                   0%
                       AEP                           Discharge Location B (Central)
                       63%                    1.14                1.12                  -2%
                       39%                    1.71                1.54                 -10%
                       18%                    2.54                2.30                  -9%
                       10%                    3.02                2.73                 -10%
                       5%                     3.69                3.55                  -4%
                       2%                     4.28                4.09                  -4%
                       1%                     4.95                4.62                  -7%



16-001014-01B | STORMWATER MANAGEMENT PLAN                      COOROY RETIREMENT COMMUNITY, TRADING POST
(SWMP) | PALM LAKE RESORTS                                                                  ROAD, COOROY                  | 12