F0002-AA007595-AAR-10-SMP · MCU14/0102.05

                  Table 5.1: Stormwater Detention Basin Summary
                                           Parameter

                                     Base Dimensions                                                     12m x 18m

                                             Depth                                                        1.25m

                                      Storage Volume                                                      245 m 3

                                     Outlet Arrangement

                                      Low Flow Outlet                              150mm diameter orifice at the base of the Tank


                                     High Flow Outlet                            225mm diameter orifice at 800mm above the base
                                                                                                  of the Tank
                  The detention tank parameters listed in Table 5.1 were calculated using XPRafts. An iterative
                  method was used to adjust the parameters until the catchment flows were reduced to the
                  predevelopment flows. Hydrographs relating to the detention tanks, including basin storage
                  volume, have been included in Appendix F.

5.1.3             MODEL RESULTS
                  The discharge rate at each discharge point is tabulated below for the existing, developed and
                  mitigated scenarios. This table shows that the proposed detention tank is successful in
                  mitigating the developed discharge back to existing rate for all of the ARI storm events.

                  Table 5.2: Stormwater Discharge Rates
                                             Existing             Developed                  Mitigated      Impact
                          ARI                Scenario              Scenario                  Scenario         (%)


                      Q1 (m3/s)                0.039                  0.161                   0.039           0%

                      Q2 (m3/s)                0.054                  0.206                   0.046          -15%
                      Q5 (m3/s)                0.076                  0.239                   0.056          -26%
                     Q10 (m3/s)                0.094                  0.269                   0.073          -22%
                     Q20 (m3/s)                0.117                  0.311                   0.110          -6%
                     Q50 (m3/s)                0.135                  0.342                   0.131          -3%

                    Q100 (m3/s)                0.155                  0.408                   0.150          -3%




139 Eumundi Noosa Road & 30 Lionel Donovan Drive, Noosaville Service Station and Retail Site—Stormwater
Management Plans
Hyder Consulting Pty Ltd-ABN 76 104 485 289                                                                                         9
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