i Return period T
(yr)
Probability P
(percent)
Gumbel variate y Flood discharge Q
(m3/s)
1 1.05 95.2 -1.113 447
2 1.11 90.1 -0.838 660
3 1.25 80 -0.476 939
4 2 50 0.367 1590
5 5 20 1.5 2465
6 10 10 2.25 3044
7 25 4 3.199 3776
8 50 2 3.902 4319
9 100 1 4.6 4858
10 200 0.5 5.296 5396