MCU25 0079 - Negotiated Reference Documents (As Published)

                 The proposed lawful point of discharge for the site shall be the existing kerb and channel within Clipper
                 Street. Stormwater runoff from the proposed development shall be collected on site and directed to the
                 kerb via the construction of new on site drainage.
                 The total impervious area of the developed site was calculated to be 679m2 which equates to
                 approximately 74% fraction impervious (fi=0.74).
                 Time of Concentration (tc)

                 The time of concentration has been determined by using a combination of standard inlet time and pipe
                 flow time as described in QUDM.

                 A standard inlet time of 5 minutes has also been deemed appropriate for the proposed development
                 time of concentration:

                 tc, developed = 5 minutes
                 3.2.1 DR AI NS re su lt s f o r d ev e lop ed s ite

                 The developed site catchment is summarised below:

                        •    Area – 0.0921 Ha

                        •    Total time of concentration (tc) – 5 minutes

                        •    Percent Impervious (fi) – 74%

                 Peak flow rates from the existing site have been determined by modelling various storm durations for
                 each AEP storm ensemble. The peak flow rate for the median AEP storm event are given in Table 2.

                 Table 2 - Developed site peak flow rates.

                                       AEP Storm Event                               Peak flow rate (L/s)

                                             1EY                                              21

                                           0.5EY                                              27

                                           0.2EY                                              38

                                             10%                                              42

                                             5%                                               50

                                             2%                                               60

                                             1%                                               66



                 3. 3       W ate r Q u ant it y C omp ar i son

                 Table 3 compares the peak flow rates for the median design storm for each of the existing and
                 developed cases.




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Document Set ID: 23959990
Version: 1, Version Date: 23/07/2025