SUPERSEDED - Compiled Reference Document - RAL25 0011 (As Published)

                                                            LINDSAY CONSULTING PTY LTD
                                                                                             RAINFALL VOLUME CALCULATIONS
Project                                                33 CRANK STREET, TEWANTIN                                                                                                                                                                      Project Number                                           250354
                                                                                                                                                                                                                                                      Client                                            Eagle Surveys

                                                                                                                                                                                                                      SITE INFORMATION

                                                                                                                                                                                       Total Site Area                                    1957        sqm
                                                                               RAINFALL INTENSITIES (FROM BOM, ARR 2016)                                                               Limiting runoff from Site (Dia 450)                 999        m3/sec          (999 voids this check)
                                                                                                                                                                                       Pavement area to Detention Tank                      0         sqm
                                                                                    Annual Exceedance Probability (AEP)                                                                Storage in bio-retention basins                      0         cbm
                                                      Duration   63.20%          50%#  20%*     10%       5%          2%                                      1%                       Roof Area into Detention Tank                       400        sqm
                                                       1 min          170           193          261           306          349                    403          443                    Site Area                                          1957        sqm
                                                       2 min          144           164          227           270          312                    369          413                    Travel length                                        60        m
                                                       3 min          136           154          212           252          290                    341          381                    Site Slope                                         0.05
                                                       4 min          129           147          201           237          272                    318          353                    Surface Roughness                                   0.2
                                                       5 min          123           140          191           225          257                    299          330                    Land Description                                     L         L/M/D
                                                      10 min          101           114          154           180          204                    235          257                    Soil Permeability                                    L         High/Medium/Low (H/M/L)
                                                      15 min          85.6          96.8         131           152          173                    198          217                    L ==> Light cover bushland, or poor grass cover, or low density pasture, or low cover bare fallows
                                                      30 min          60.3          68.3         92.7          109          124                    143          158                    M ==> Medium Density Bush, or good grass cover, or high density pasture, or zero tilling cropping
                                                       1 hour           40          45.5         62.8          74.3         85.6                   100          112                    H ==> Dense Bushland
                                                       2 hour         25.9          29.7         41.8          50.1         58.3                   69.4         78.1                   Un-Developed Fraction Impervious                    0.4                        From Fig. 4.05.1 in QUDM (2007)
                                                       3 hour         20.1          23.2           33          39.8         46.6                   55.9         63.1                   Developed Fraction Impervious                       0.9                        From Fig. 4.05.1 in QUDM (2007)
                                                       6 hour         13.1          15.3         22.1            27         31.9                   38.6         43.9                   One Hr rainfall Intensity for Q10                        74.3 mm/hr
                                                      12 hour         8.64          10.1         14.9          18.3         21.8                   26.6         30.4                   Calculated Travel Time                               9         Min             Must equal time selected for intensity
                                                      24 hour         5.63          6.61         9.86          12.2         14.7                     18         20.8                   Adopted Storm Time                                   9         min
                                                      48 hour         3.55          4.17         6.25          7.82         9.47                   11.8         13.7
                                                      72 hour         2.65           3.1         4.66          5.86         7.13                   8.97         10.5                   Detention Tank Provided                           10000        lt




                                                                                                                                                         Return interval (ARI)
                                                                           1                          2                                 5                             10                           20                              50                            100
          Intensity (for Return Interval)                                105.40                     119.20                            161.40                       189.00                        214.60                          247.80                         271.60
                                                                 Undeveloped     Developed   Undeveloped    Developed   Undeveloped          Developed      Undeveloped    Developed    Undeveloped      Developed     Undeveloped       Developed     Undeveloped      Developed
          C10 value                                                0.780          0.880        0.780         0.880        0.780               0.880           0.780         0.880         0.780           0.880           0.780           0.880            0.780         0.880
          Fy Factor                                                0.800          0.800        0.850         0.850        0.950               0.950           1.000         1.000         1.050           1.050           1.150           1.150            1.200         1.200
          Cy                                                       0.624          0.704        0.663         0.748        0.741               0.836           0.780         0.880         0.819           0.924           0.897           1.012            0.936         1.056
          Q (m3/sec)                                               0.036          0.040        0.043         0.049        0.065               0.073           0.080         0.090         0.096           0.108           0.121           0.136            0.138         0.156
          Total Rainfall for event (m3)                                    22                          27                               40                            49                            59                              74                             85
          Total Non-Worsening Volume for Storm (m3)                         3                          3                                 5                             6                             7                               9                             10
          Roof Area Runoff for Storm (m3)                                   4                          5                                 8                             9                            11                              15                             17