АНАЛІЗ ПОВТОРЮВАНОСТІ ДОЩОВИХ ПАВОДКІВ НА РІЧКАХ В БАСЕЙНІ ТИСИ (В МЕЖАХ УКРАЇНИ)

Abstract

Rain floods on the rivers in the Tisza basin within Ukraine are formed several times during the entire warm period. The purpose of the presented study is a detailed analysis of the frequency of such floods on the rivers of the region under study in terms of the series of annual maximum average daily water discharges and the series of maximum average daily discharges of partial probability. The first series, called the “multi-annual series”, includes only one of the highest discharges each year, in our case, one for the warm period – May-October. The second row includes all values hat exceed some limit value, which corresponds to the smallest value from the series of annual maximum annual water discharges. To carry out the work, we used observational data on the average daily water flow from the following hydrological posts on the rivers: the Uzh River – Uzhgorod, the Latoritsa River – Mukachevo, the Rika River – Mezhgorye, the Teresva River – Ust-Chernaya, the Tisza River – Rakhiv for the observation period 1946 (47 ) to 2019. To obtain the long-term series and partial probability necessary for the study, first, chronological samples of rain flood maxima were formed for both series separately, then they were ranked and the estimated return period was determined for each member of the series. The series of maximums of partial probability according to the data from the studied hydrological stations in their number on average 4-6 times exceed the number of values of the series of annual maxima. The calculated return periods are determined by the inverse formula to the Weibull formula. Graphs of the frequency of rain floods by annual maxima and maxima of partial probability for the stations under study were constructed, which made it possible to notice the following features: 1) the discharges maxima of rain floods with a frequency of less than 5-10 years differ for a number of annual maximum water discharges and a series of partial probability; 2) partial probability series better describe minor floods, especially those with a short return period. The analysis of the frequency of rain floods on the rivers in the Tisza basin within Ukraine made it possible to estimate the possible magnitudes of rain floods that can form during a warm period of time and to estimate their frequency of a certain magnitude. This is of practical interest as knowledge of potential floods can be used to assess the nature of potential floods in the future.