SCG 31131(SWM).RevB - REceived 3.3.22.pdf

6.1.4    Runoff Coefficient (C10)



The 10year runoff coefficients (C10) were calculated as defined in QUDM. Refer to Table 6.2 for
Adopted C10 Values: -

                                             Table 6.2: C10 Values

                STATE                  CATCHMENT A (C10)                   CATCHMENT B (C10)

          Pre Development                         0.78                               0.74

          Post Development                        0.88                               0.88



6.1.5    Peak Flows



Table 6.3 below displays a summary of major and minor discharge rates for pre and post development
conditions using the rational method. Refer to Appendix E for calculations: -

                             Table 6.3: Pre and Post Development Peak Flow Rates

            Condition          Q1         Q2              Q5      Q10       Q20          Q50       Q100
                              (m3/s)     (m3/s)          (m3/s)   (m3/s)    (m3/s)      (m3/s)    (m3/s)

        Pre Development       0.010      0.013           0.019    0.024     0.029       0.037     0.042
          Catchment A

        Post Development      0.028      0.034           0.051    0.063     0.076       0.095     0.105
          Catchment A

        Pre Development       0.063      0.076           0.114    0.140     0.167       0.210     0.240
          Catchment B

        Post Development      0.070      0.084           0.128    0.159     0.191       0.241     0.266
          Catchment B

               Total          0.074      0.089           0.134    0.164     0.195       0.247     0.282
        Pre Development

               Total          0.098      0.118           0.179    0.222     0.267       0.336     0.370

        Post Development



SCG Consulting Engineers                    Page 17                                  SCG Ref: 31131(SWMP).RevB