Apdx 4 - SWMP

Rational Method Calculations

    Project        221304

   Address         23 Coral Tree Avenue                                                        By           DK


            Pre - Development                                                                       Post - Development
               Catchment Details                                                                        Catchment Details
     Area             0.0607           ha                                                     Area             0.0607          ha
       fi              0.43                                                                     fi              0.62
     C10           0.78632619                                                                 C10           0.82355848
      I10              74.9          mm/hr                                                     I10              74.9         mm/hr

              Standard Inlet Time                                                                     Standard Inlet Time
     Time               5             mins                                                    Time                5           mins

    Overland Sheet Flow (Friend's Eqn)                                                       Overland Sheet Flow (Friend's Eqn)
    Length                         m                                                         Length                         m
     Slope                         %                                                          Slope                         %

  Surface 'n'                                                                              Surface 'n'

     Time               0             mins                                                    Time                0           mins

           Pipe Flow Travel Time                                                                    Pipe Flow Travel Time
Flow Distance                          m                                                 Flow Distance                         m
Fall of Channel                        m                                                 Fall of Channel                       m
      Time                            mins                                                     Time                           mins

                   Kerb Flow                                                                                Kerb Flow
    Length                             m                                                     Length                            m
     Slope                             %                                                      Slope                            %
     Time              0.0            mins                                                    Time                0.0         mins

    Channel Flow (Figure 4.8 QUDM, or                                                        Channel Flow (Figure 4.8 QUDM, or
          Manning's Equation)                                                                      Manning's Equation)
Flow Distance                          m                                                 Flow Distance                         m
Fall of Channel                        m                                                 Fall of Channel                       m
      Time                            mins                                                     Time                           mins


 Adopted Time of                                                                          Adopted Time of
  Concentration
                        5             mins                                                 Concentration
                                                                                                                  5           mins



      Pre-Development Peak Discharges                                                         Post-Development Peak Discharges
                                                            Design Storm   Frequency
   Area (ha)            Cy          Iy (mm/h)   Qy (m3/s)      (AEP)       Factor (Fy)
                                                                                            Area (ha)             Cy        Iy (mm/h)   Qy (m3/s)

    0.0607         0.62906096         125        0.013       63.20%          0.80            0.0607         0.65884679        125        0.014
    0.0607         0.66837727         157        0.018       39.35%          0.85            0.0607         0.70002471        157        0.019
    0.0607         0.74700988         196        0.025       18.14%          0.95            0.0607         0.78238056        196        0.026
    0.0607         0.78632619         226        0.03         10%            1.00            0.0607         0.82355848        226        0.031
    0.0607          0.8256425         258        0.036         5%            1.05            0.0607         0.86473641        258        0.038
    0.0607         0.90427512         300        0.046         2%            1.15            0.0607         0.94709226        300        0.048
    0.0607         0.94359143         331        0.053         1%            1.20            0.0607         0.98827018        331        0.055

                                                            Discharge Comparison
                      AEP           63.20%       39.35%     18.14%            10%              5%                 2%          1%
                   Difference        0.001        0.001      0.001            0.001           0.002              0.002       0.002
                   Percentage        7.7%         5.6%       4.0%             3.3%            5.6%               4.3%        3.8%