B07056.W-01A Complete - Stormwater [As Published] · 132007.2398

                                                                                                                                                                                                                                                             Appendix B



             Time of Concentration and Rational Method Calculations
             Job:    RSL Care, Cooroy
             File:   H:\B07\050-099\B07056 - RSL Care Cooroy.WW\DRAINS\[B07056 070802 Rational Method Calculations.xls]North
             Date:   2/08/2007
             By:     KU

             TIME OF CONCENTRATION CALCULATIONS                                                EXISTING NORTHERN CATCHMENT
                                                                                                                                                                        Wetted
                                                                                                           Length          Av. Slope      Se         Velocity  Wetted Perimeter                   Slope
                                                                                                                                                                     2
             Reference                   Equation Type / Method                                Area (ha)    (km)              (%)       (m/km)        (m/s)   Area (m )  (m)          R          Modifier   Rs      Manning's n Chez's Coeff      tc (min)
             AR&R                        Eastern NSW Rational Method                             7.401                                                                                                                                               17

             5.05.3A QUDM                Bransby Williams                                          7.401    0.332                        14.9                                                                                                       15

             5.05.1 QUDM                 Overland Flow Based on Friends Equation                               0.11           2.1                                                                                     0.045                         20

             Table 5.05.4 QUDM           Concentrated Flow Based on Average Velocities                         0.01          15.2                       3                                                                                           0
                                                                                                               0.01          -13.9                     0.3                                                                                          0
                                                                                                               0.04           0.0                      0.3                                                                                          2
                                                                                                               0.05           1.6                      0.7                                                                                          1
                                                                                                               0.08           1.3                      0.3                                                                                          4
                                                                                                               0.05           3.5                      0.7                                                                                          1
                                         Overland Flow + Concentrated Flow                                                                                                                                                                          30

                                                                                                                                                                                                                               Average tc (min)    21
                                                                                                                                                                                                                              Adopted tc (min)     28
                                                                                                                                                                                                                                Range tc (min)    21-30

             FLOW CALCULATIONS

             5.02.2 QUDM                 Queensland Rational Method                            For a tc of 28 min & Area of 7.401 ha.                                     Flow Summary
                                         Trial 2                                                    tc of      30     min                                                 tc             21       28       30
                                                                                                                          tc
                                                             ARI                                  C10          Cy            Iy    A (ha)            Q (m3/s)                      Q (m3/s) Q (m3/s) Q (m3/s)
                                                               1                                 0.71         0.57       0.0       7.401               0.00
                                                               2                                 0.71         0.60       72.0      7.401               0.89                               1.07       0.94    0.89
                                                               5                                 0.71         0.67       90.0      7.401               1.25                               1.50       1.30    1.25
                                                              10                                 0.71         0.71      100.0      7.401               1.46                               1.73       1.53    1.46
                                                              20                                 0.71         0.75      120.0      7.401               1.84                               2.08       1.88    1.84
                                                              50                                 0.71         0.82      140.0      7.401               2.35                               2.71       2.40    2.35
                                                             100                                 0.71         0.85      148.0      7.401               2.59                               3.02       2.69    2.59

                                                                                                                             ARI
                                                                                                               Mins           1            2            5         10         20       50           100
                                                                                                                      30                        72           90     100        120         140       148
                                                                                                                      45                        58           75      82         95         118       122

                                                                                                                                       IFD Data
                                         Road Impervious                                             3388 m2                                           ARI
                                         North Catchment                                            74010 m2                             Mins           1         2          5        10            20       50        100
                                         fi =                                                       5%                                          20                87        110      120           138      165        175
                                         I (1hr, 10 min) =                                     70 mm/hr                                         25                82        100      112           126      148        162
                                         C10 = (from QUDM Table 5.04.2                             0.71                                         30                72         90      100           120      140        148
                                                                                                                                                45                58         75       82            95      118        122


H:\B07\050-099\B07056 - RSL Care Cooroy.WW\DRAINS\B07056 070802 Rational Method Calculations.xls