ABSTRACT
The design of hydraulic structures often requires hydrological information governed by the laws of probability and statistics. This results in the necessity of using the statistical and probabilistic analyses of hydrological data. Deterministic hydrology deals with causes and assesses hydrological variables and processes with complete certainty; thus, it cannot cover the random component of the hydrological variables, something significantly impacting both simulation and forecast. This has led to the development of the field of statistical hydrology. This branch of hydrology, which deals with the analysis of hydrological variables, is divided into probabilistic hydrology and stochastic hydrology. Probabilistic hydrology analyzes and synthesizes hydrological events without taking into account their temporal sequence, i.e. the probability P of the variable to have a specific value at the spatiotemporal point of zero. The theory of probability provides the framework for modelling processes that we cannot determine precisely. Stochastic hydrology takes into account the time sequence and considers the probability, previously reported equal to ε, where ε is a positive number between 0 and 1. In hydrological variables, there are two categories of uncertainty: (1) natural randomness and (2) imprecise knowledge of reality.
