flow  duration   cumsum
0   0.167    26.220   26.220
1   0.139    32.112   58.332
2   0.020     5.978   64.310
3   0.041    11.418   75.728
4   0.108    22.391   98.119
5   0.130    28.018  126.137
6   0.205    36.227  162.364
7   0.096    66.922  229.286
8   0.124   102.785  332.071
9   0.224    50.764  382.835
10  0.176    30.545  413.380
11  0.233    50.217  463.597
12  0.078    21.255  484.852
13  0.328    38.634  523.486
14  0.107    24.581  548.067
15  0.167    26.220  574.287
16  0.062    20.560  594.847
17  0.159    20.641  615.488
18  0.101    12.844  628.332
19  0.170    17.294  645.626