Reference Douments - 132004.4029.01 & RAL22/0010

                                                 Figure 3.2 – DRAINS Post-development catchments


       The results of the modelling against the range of design storms for the development under the existing and
       proposed development conditions are shown in Table 3.1 Existing and proposed unmitigated site peak discharge
       rates.
                                       Table 3.1 Existing and proposed unmitigated site peak discharge rates

                                                                            Wyandra Street
                                                                                                            Qchange
                                                 A.E.P               Qexisting    Qproposed    Qchange       (%)
                                                                     (m³/s)       (m³/s)       (m³/s)
                                                   1EY                0.024        0.027        0.003        13%
                                                  50%                 0.029        0.029       0.000          0%
                                                 0.2 EY               0.044        0.045       0.001          2%
                                                  10%                 0.053        0.053       0.000          0%
                                                   5%                 0.061        0.061       0.000          0%
                                                   2%                 0.070        0.071       0.001          1%
                                                   1%                 0.078        0.078       0.000          0%



       The site has only resulting in minor increases to peak run-off for less than half of the modelled storm events. With the
       increase being a maximum of 3L/s, the impact to downstream drainage conditions will be insignificant and unlikely
       to result in damage or nuisance to downstream properties and infrastructure. Attenuation is therefore not required
       for the proposed development.




      Project number 20220116
      File RECOR Preliminary Stormwater Management Report - 20220116.docx, 2022-09-27                                   Page 8 of 14
      Revision 1

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