Assessment of normative design extreme characteristics of runoff using different distribution laws

Abstract

Water management problems are among the prior problems in the world. The solution of each of them is determined by hydrological and water management studies, the conclusions of which also serve to determine the main design characteristics that are used for further structural and hydraulic engineering design. The correct solution of the hydrological part of the problem is a prerequisite for further success. The differences between the calculated values of the extreme values of the runoff using the three-parameter gamma distribution and the Pearson type III binomial distribution, which are used in the practice of hydrological calculations of the Russian Federation, were investigated in the work. Considering the still small periods of observations of river flow, the parameters of the distribution of flow values have some errors relative to its true value. The errors of these parameters are affected by the chosen distribution law. As a rule, the asymmetry coefficient is determined with the greatest error. In this paper, an assessment of the statistical error was carried out and the need for correction of corrections in the range P = 95% – 99% was proved, which should be provided for at the next update of regulatory documents, since the error in some cases reaches 47%.