Once a cumulative frequency is known, the maximum rainfall
intensity is determined using the chosen theoretical distribution
function such as normal, Weibull, and lognormal (Griffis and
Stedinger 2007b; Mailhot et al. 2007; Mirhosseini et al. 2014;
Solaiman et al. 2011). The objective of frequency analysis is to
relate the magnitude of events to their frequency of occurrence
through probability distribution. It is assumed the events (i.e., data)
are independent and come from identical distribution. Once a distribution
function has been selected and its parameters estimated in
this case the normal distribution function (Fig. 7) is selected since
forecasting the cumulative probability of the maximum annual rainfall
result using the normal and Weibull are very close, as described
previouslyn