“…Typically, the uncertainty measure for the quantile estimate in the frequency analysis approach is provided as a confidence interval [45] and/or standard error [46]. A predefined probability distribution usually based on the modern extreme value theory is assumed to fit the historical data series (i.e., Gumbel, Frechet, Weibull, and generalized extreme value (GEV) to fit an AM series and generalized Pareto (GP) to fit a POT series) [9,29,45,[47][48][49][50][51]. Numerous approaches have been employed in the literature to generate confidence intervals, for example, using a formula that depends on the probability distributions and the parameter estimation techniques [52][53][54], using the profile-likelihood approach [7,32], using artificial neural networks [55], using deep learning method (such as the long short-term memory (LSTM) method) [56], Bayesian methods [48,50], Monte Carlo simulation methods [57,58], and bootstrap methods [45,49,51].…”