Att 2 SWMP

Rational Method Calculations
Project number:                                    20210121                                                                        Calculations:                                       B. Parry
Street Address                                     16 Rene St                                                                      Date:                                               7/10/2021
Locality:                                          Noosaville, Noosa Shire Council




Site Area Composition

Existing Site Roof Area:                                                   350.5 m2                                                Developed Site Roof Area:                                         477.62 m2
Existing Site Paved Area:                                                 265.19 m2                                                Developed Site Paved Area:                                        396.28 m2
Existing Site Total (Impermeable):                                        615.69 m2                                                Developed Site Total (Impermeable):                                873.9 m2
Existing Site Total (Permeable):                                       683.3445 m2                                                 Developed Site Total (Permeable):                               425.1345 m2

Total Site Area:                                                      1299.0345 m2                                                 Increase Impermeable Area:                                       258.210 m2
                                                                                                                                                                                                      0.026 Ha.


Time of Concentration

Existing Site                                                                                                                      Proposed Site

                                              tc                             5.0 mins                                                                                             tc                   5.00 mins



Rational Method - Peak Flow Calculation

Existing Site                                                                                                                      Proposed Site
                                   Area (Ha.)                              0.130 Ha.                                                                                       Area                       0.130 Ha.
                                           fi                              0.474                                                                                              Fi                      0.673
                                         1                                                                                                                                   1
                                             I10                          80.987 mm/hr                                                                                           I10                 80.987 mm/hr
                                          C10                               0.79                                                                                             C10                       0.83




A.E.P                                              Fy                              Cy            Iy            Qy (m3/s)           A.E.P                                               Fy                     Cy            Iy            Qy (m3/s)
                                   63.2% AEP                                 0.8         0.636        135.16               0.031                                       63.2% AEP                        0.8         0.668        135.16               0.033
                                    50% AEP                                 0.85         0.676        152.60               0.037                                         50% AEP                       0.85         0.709        152.60               0.039
                                    20% AEP                                 0.95         0.755        208.19               0.057                                         20% AEP                       0.95         0.793        208.19               0.060
                                    10% AEP                                    1         0.795        245.25               0.070                                         10% AEP                          1         0.835        245.25               0.074
                                      5% AEP                                1.05         0.835        280.13               0.084                                          5% AEP                       1.05         0.876        280.13               0.089
                                      2% AEP                                1.15         0.914        325.91               0.107                                          2% AEP                       1.15         0.960        325.91               0.113
                                      1% AEP                                 1.2         0.954        360.79               0.124                                          1% AEP                        1.2         1.001        360.79               0.130