Swmp

       RATIONAL METHOD SUMMARY & RAINFALL DATA
      Project   25 Pavilion Street, Pomona
      Project #

      2016 IFD BoM

      Latitude             -26.36
      Longitude            152.85


      Rainfall Intensity (mm/hr)

            DURATION                                        AVERAGE RECURRENCE INTERVAL (years)
        (hours) (minutes)                  1 yr            2 yr    5 yr   10 yr   20 yr    50 yr                  100 yr
         0.083     5                       112             127     171    201     230      267                     295
          0.1      6                       108             122     164    192     219      254                     280
         0.167     10                       92             104     140    164     186      214                     235
         0.25      15                       78              88     119    139     157      181                     199
         0.333     20                       68              77     104    121     137      158                     174
         0.417     25                       61              69     92     108     123      142                     156
          0.5      30                       55              62     84      98     111      129                     142
         0.75      45                      43.2            48.7    66      77      89      103                     114
           1       60                      36.1            40.7    55      65      75       88                      98
          1.5      90                      27.9            31.5   43.1     51      59       70                      78
           2      120                      23.2            26.3   36.1    43.0    49.8      59                      66
           3      180                      17.9            20.4   28.3    33.9    39.4     47.0                     53
          4.5     270                      13.9            15.9   22.4    26.9    31.5     37.7                    42.6
           6      360                      11.7            13.4   19.0    23.0    26.9     32.4                    36.7
           9      540                      9.13            10.6   15.2    18.5    21.8     26.3                    29.8
          12      720                      7.69            8.94   13.0    15.8    18.7     22.7                    25.9
          18      1080                     6.03            7.05   10.4    12.7    15.1     18.5                    21.1
          24      1440                     5.05            5.93   8.80    10.9    13.0     15.9                    18.2
          30      1800                     4.38            5.16   7.71    9.55    11.4     14.1                    16.2
          36      2160                     3.89            4.59   6.89    8.56    10.3     12.7                    14.7
          48      2880                     3.20            3.78   5.72    7.14    8.61     10.7                    12.4
          72      4320                     2.39            2.83   4.30    5.40    6.55     8.22                    9.60


      Catchment Data

      Details:      EXISTING

       Variable         Value             Units
         Area:          3.407               ha
          C10           0.66             fraction

                                                           17.4      Overland Flow190
                                                                                   - 120m
      Rational Method Summary                              2.60      channel      120

        Adopted Time of Concentration (tc)                 20.6      Minutes (or 0.34 hours)

                                                           AVERAGE RECURRENCE INTERVAL (years)
              Variable                     1 yr            2 yr   5 yr   10 yr   20 yr    50 yr                   100 yr
             Freq Factor                  0.80            0.85   0.95    1.00    1.05     1.15                     1.20
          Intensity (mm/hr)                 67             76     102    119      135     156                      172
          Discharge (m3/s)                0.336           0.403  0.608  0.745    0.886   1.120                    1.286




H:\21\21-0166 25 Pavilion Street, Pomona - SMP\Design\Water Resources\WBNM\Rational\Rational_Method_Pomona.xlsm            12/08/2021


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RATIONAL METHOD SUMMARY & RAINFALL DATA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Project 25 Pavilion Street, Pomona
Project #
2016 IFD BoM
Latitude -26.36
Longitude 152.85
Rainfall Intensity (mm/hr
DURATION AVERAGE RECURRENCE INTERVAL (years)
(hours) | (minutes) 1 yr 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr
0.083 5 112 127 171 201 230 267 295
0.1 6 108 122 164 192 219 254 280
0.167 10 92 104 140 164 186 214 235
0.25 15 78 88 119 139 157 181 199
0.333 20 68 77 104 121 137 158 174
0.417 25 61 69 92 108 123 142 156
0.5 30 55 62 84 98 111 129 142
0.75 45 43.2 48.7 66 77 89 103 114
1 60 36.1 40.7 55 65 75 88 98
1.5 90 27.9 31.5 43.1 51 59 70 78
2 120 23.2 26.3 36.1 43.0 49.8 59 66
3 180 17.9 20.4 28.3 33.9 39.4 47.0 53
4.5 270 13.9 15.9 22.4 26.9 31.5 37.7 42.6
6 360 11.7 13.4 19.0 23.0 26.9 32.4 36.7
9 540 9.13 10.6 15.2 18.5 21.8 26.3 29.8
12 720 7.69 8.94 13.0 15.8 18.7 22.7 25.9
18 1080 6.03 7.05 10.4 12.7 15.1 18.5 21.1
24 1440 5.05 5.93 8.80 10.9 13.0 15.9 18.2
30 1800 4.38 5.16 7.71 9.55 11.4 14.1 16.2
36 2160 3.89 4.59 6.89 8.56 10.3 12.7 14.7
48 2880 3.20 3.78 5.72 7.14 8.61 10.7 12.4
72 4320 2.39 2.83 4.30 5.40 6.55 8.22 9.60
Catchment Data
Details: EXISTING
Variable Value Units
Area: 3.407 ha
Cio 0.66 fraction
17.4 Overlandf 190
Rational Method Summary 2.60 channel 120
Adopted Time of Concentration (tc) __ 20.6 _ Minutes (or 0.34 hours)
AVERAGE RECURRENCE INTERVAL (years)
Variable T yr 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr
Freq Factor 0.80 0.85 0.95 1.00 1.05 1.15 1.20
Intensity (mm/hr) 67 76 102 119 135 156 172
Discharge (m*/s) 0.336 0.403 0.608 0.745 0.886 1.120 1.286

 

 

 

 

 

 

 

 

 

 

H:\21\21-0166 25 Pavilion Street, Pomona -

SMP\Design\Water Resources\WBNM\Rational\Rational_Method_Pomona.xlsm

12/08/2021