flow  duration   cumsum
0   0.135    19.341   19.341
1   0.219    33.897   53.238
2   0.325    22.634   75.872
3   0.155    21.786   97.658
4   0.000    30.000  127.658
5   0.060    21.509  149.167
6   0.125   103.548  252.715
7   0.166    41.656  294.371
8   0.352    48.704  343.075
9   0.137    12.504  355.579
10  0.106    15.242  370.821
11  0.045    12.098  382.919
12  0.126   102.015  484.934
13  0.141    19.292  504.226
14  0.124   102.785  607.011
15  0.060    21.509  628.520
16  0.062    20.560  649.080
17  0.048    19.948  669.028
18  0.204    26.179  695.207
19  0.000    30.000  725.207