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]South
           Date:    2/08/2007
           By:      KU

           TIME OF CONCENTRATION CALCULATIONS                                                      EXISTING SOUTHERN CATCHMENT
                                                                                                                                                                           Wetted
                                                                                                               Length         Av. Slope      Se         Velocity  Wetted Perimeter               Slope
           Reference                      Equation Type / Method                                   Area (ha)    (km)             (%)       (m/km)        (m/s)   Area (m2)  (m)      R          Modifier   Rs      Manning's n Chez's Coeff      tc (min)
           AR&R                           Eastern NSW Rational Method                                6.265                                                                                                                                          16

           5.05.3A QUDM                   Bransby Williams                                           6.265      0.384                       28.4                                                                                                   15

           5.05.1 QUDM                    Overland Flow Based on Friends Equation                                 0.2            1.9                                                                                 0.045                         25

           Table 5.05.4 QUDM              Concentrated Flow Based on Average Velocites                            0.01          14.2                      1.5                                                                                      0
                                                                                                                  0.02          3.5                       0.7                                                                                      1
                                                                                                                  0.05          0.0                       0.3                                                                                      3
                                                                                                                  0.02          6.6                       0.9                                                                                      0
                                                                                                                  0.04          1.8                       0.7                                                                                      1
                                                                                                                  0.01          14.4                      1.5                                                                                      0
                                                                                                                  0.04          2.0                       0.7                                                                                      1
                                          Overland Flow + Concentrated Flow                                                                                                                                                                        31

                                                                                                                                                                                                                              Average tc (min)    21
                                                                                                                                                                                                                             Adopted tc (min)     28
                                                                                                                                                                                                                               Range tc (min)    21-31

           FLOW CALCULATIONS

           5.02.2 QUDM                    Queensland Rational Method                               For a tc of 28 min & Area of 6.265 ha.                                Flow Summary
                                          Trial 2                                                       tc of      31     min                                            tc             21       28       31
                                                                                                                              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       6.265              0.00
                                                                2                                    0.71         0.60       71.1      6.265              0.75                           0.90       0.80    0.75
                                                                5                                    0.71         0.67       89.0      6.265              1.04                           1.27       1.10    1.04
                                                               10                                    0.71         0.71       98.8      6.265              1.22                           1.46       1.29    1.22
                                                               20                                    0.71         0.75      118.3      6.265              1.54                           1.76       1.59    1.54
                                                               50                                    0.71         0.82      138.5      6.265              1.97                           2.30       2.03    1.97
                                                              100                                    0.71         0.85      146.3      6.265              2.17                           2.56       2.28    2.17

                                                                                                                                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                                               2864 m2                                           ARI
                                          South Catchment                                              62650 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