5179Flood Report_REV_3

                                                                                      Callaghan & Toth




1.        BYPASS CAPACITY

The bypass facility is a 525 mm pipe along Spotted Gum Court in the adjoining development to the
south.

That bypass pipe was originally intended to have a Q5 capacity.

Callaghan & Toth’s 2018 Council-approved HGL tabulation for the bypass pipe indicates a design flow
rate of 0.434 m3/sec at a HWL of 104.602 (c.f. surface level of 105.359) and a TWL of 102.185.

 Qcap = [ (105.359 – 102.185) / (104.602 – 101.805) ]0.5 x 0.434 = 0.46 m3/sec.




2.        DESIGN RAINFALL INTENSITIES
Based on ARR 1987




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2035 2 Pearsons Road – Flood Study – Revision 3                                    April 2021