Stormwater Management Plan · MCU15/0122

                                                                                                15099 - SBSMP/2
                                                                                                             Page 14




5.7 Comparison of Peak Flows at the Legal Point of Discharge
All roof runoff generated from the propose development will be detained within the detention
basin. Table 5.6 below provides a comparison of the pre-development and post-development
(mitigated) peak flows at the legal point of discharge (LPD) for the proposed development.

                            Table 5.6 - Comparison of Peak Flows at the LPD

                        XP-RAFTS                        XP-RAFTS
    ARI                                                                                      Difference
                   Pre-developed Flows           Developed Flows (Mitigated)
  (years)                  (m3/s)                            (m3/s)                    (m3/s)               %
                           0.150                              0.133
     2                                                                                 -0.017             -11.3
                      (2yr 25min storm)                 (2yr 25min storm)
                           0.199                              0.182
     5                                                                                 -0.017               -8.5
                      (5yr 25min storm)                 (5yr 25min storm)
                           0.222                              0.204
     10                                                                                -0.018               -8.1
                     (10yr 25min storm)                (10yr 25min storm)
                           0.255                              0.231
     20                                                                                -0.024               -9.4
                     (20yr 25min storm)                (20yr 25min storm)
                           0.271                              0.243
     50                                                                                -0.028             -10.3
                     (50yr 25min storm)                (50yr 25min storm)
                           0.301                              0.274
    100                                                                                -0.027               -9.0
                     (50yr 25min storm)                (100yr 25min storm)
    Notes:
        1.   Additional detention volume will be achieved in the internal roofwater and stormwater pipes.




The XP-RAFTS hydraulic modelling has demonstrated that the proposed on-site detention to be
implemented will maintain pre-development flows (or less) for all design storms at the LPD.
Refer Appendix D and to Appendix E for peak flows at the LPD for the pre-development and
post-development mitigated site, as summarised in Table 5.6 above.

Refer to Appendix C for concept drainage plans of the proposed development.

This plan is required to be confirmed during detailed design to ensure that the operational
requirements are considered suitable. Substantial changes may require resubmission of this
report to the local authority.




Site Based Stormwater Management Plan
Proposed Medical Development at Cnr Val Crescent & Goodchap Street, Noosaville