Attachment 6 - Stormwater Management Plan and Engineering Response. · MCU23/0078

                                  Table 13: XP Storm Developed Model Parameters – Lot 7 (South)
                                       Parameter                Lot 7 Southern Catchment
                                                               Pervious Data           Impervious Data
                                 Area (ha)                            0.034                 0.304
                                 Slope (%)                             2.5                     2.5
                                 Mannings ‘n’                          0.03                 0.013
                                 Initial Loss (mm)                     27                        0
                                 Continuing Loss (mm/hr)               2.6                       0
                                 Laurenson ‘n’                        -0.285               -0.285

4.2.5   Results for Developed Unmitigated Scenario


        Table 14, Table 15, and Table 16 indicates the developed unmitigated total peak discharge rate for the sites as outputted
        by XP storm for both Lot 3 and the two sub-catchments of Lot 7 (North and South). The critical storm duration for the
        existing catchment was determined by simulating all storm events from the 1 to 100-year ARI storm events for 20, 25, 30,
        45, 60, 90, 120 and 180-minute durations. The critical storm events can be seen within tables below.


                          Table 14: XP Storm Developed Unmitigated Peak Flow Results – Lot 3 (m3/sec)
                                                                    ARI & AEP
                  Storm Duration
                                     1 Years  2 Years   5 Years   10 Years   20 Years    50 Years     100 Years
                      (min)
                                       63%      39%      18%        10%        5%           2%           1%
                         20             1.219        1.386     1.892           2.222     2.535       2.704      2.978
                         25             1.217        1.380     1.880           2.218     2.543       2.652      2.936
                         30             1.114        1.264     1.729           2.045     2.351       2.492      2.766
                         45             0.997        1.132     1.562           1.850     2.129       2.347      2.619
                         60             1.051        1.202     1.690           2.028     2.368       2.619      2.938
                         90             0.895        1.026     1.471           1.785     2.089       2.180      2.452
                        120             0.865        0.992     1.425           1.744     2.057       2.138      2.420
                        180             0.565        0.659     0.944           1.141     1.337       1.425      1.618
                      Critical          1.219        1.386     1.892           2.222     2.543       2.704      2.978
                Critical Even (Min)          20       20         20             20        25          20          20

                      Table 15: XP Storm Developed Unmitigated Peak Flow Results – Lot 7 (North) (m3/sec)
                                                                    ARI & AEP
                  Storm Duration
                                     1 Years   2 Years 5 Years    10 Years   20 Years     50 Years   100 Years
                      (min)
                                       63%      39%      18%        10%         5%          2%           1%
                         20             0.105        0.119     0.161           0.188     0.214       0.227      0.250
                         25             0.102        0.115     0.157           0.187     0.216       0.226      0.250
                         30             0.093        0.105     0.144           0.173     0.200       0.212      0.236
                         45             0.085        0.096     0.132           0.155     0.178       0.196      0.221
                         60             0.089        0.102     0.145           0.175     0.204       0.224      0.250
                         90             0.077        0.090     0.130           0.155     0.180       0.186      0.208
                        120             0.075        0.086     0.126           0.153     0.178       0.184      0.206
                        180             0.048        0.055     0.082           0.099     0.116       0.123      0.139
                      Critical          0.105        0.119     0.161           0.188     0.216       0.227      0.250
                Critical Even (Min)          20       20         20             20        25          20          20




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