Problem 8-1

Use the Weibull formula (Eq. 6-26) to calculate the plotting positions for the following series of annual maxima, in cubic feet per second:
8020, 3260, 2210, 1735, 5550, 3560, 3745, 3040, 3500, 2010, 1835, 7350, 4350, 2890, 2620, 1405, 1165, 5505, 6080, 6215, 7015, 6925

Problem 8-2

Fit a log Pearson III curve to the data of Problem 8-1. Plot the calculated distribution on log probability paper, along with the Weibull plotting positions calculated in Problem 8-1 (If using Excel, plot in semilog paper, with discharge in the log scale).

Problem 8-3

Given the following statistics of annual maxima for river Y: number of years n = 35; mean = 1550 m³/s; standard deviation= 435 m³/s; mean of the logarithms = 3.05; standard deviation of the logarithms = 0.3; skew coefficient of the logarithms = -0.2. Compute the 100-y flood using the following probability distributions: (a) normal, (b) Gumbel, and (c) log Pearson III.