A 4-hour storm in a catchment area results in the following discharge ordinates of the direct runoff hydrograph of 4 cm excess rainfall:
|
Duration (hr) |
0 |
4 |
8 |
12 |
16 |
20 |
24 |
28 |
|
Ordinate (m3/s) |
0 |
10 |
15 |
20 |
40 |
25 |
5 |
0 |
Then the peak ordinate of an 8-hour storm which gives 2 cm excess rainfall is:
1
16.15
2
65
3
18.5
4
40