On Issue of Determining the Maximum Flow Rate

Abstract

Purpose: to obtain equations for further use in calculating the maximum discharge of 1% availability along the whole river length, depending on watershed elevation (for the Black Sea basin rivers), based on the dependency curves. Materials and methods. The calculated and reference data of hydrometeorological services (series of observations for maximum water discharges) were the base materials. From the reference materials, the following hydrological characteristics were obtained: watershed area, average watershed elevation and 1% flow probability. The studies were carried out for 59 control stations on 14 rivers. Results. Dependence curves and equations for calculating the maximum flow rate of 1% flow probability for 14 rivers of the Black Sea basin, ranked according to watershed elevation into four groups: 0–500, 500–1000, 1000–1500, 1500–2500 m according to the Baltic System (BS) are obtained. A comparison of flow rates obtained from the calculated curves and available reference data was made, according to its results the average error about 25 % was determined. In the proposed method, there is a tendency to overestimate the values compared to the reference data. Conclusions. The calculated equations for flow rates of 1% probability in the elevation range of 0–500 and 500–1000 m BS, obtained as a result of the study, are very reliable and can be used to calculate the given value. To improve the accuracy of the equations in the elevation range of 1000–1500 and 1500–2500 m BS, along with the available data, it is recommended to use additional control stations in the corresponding elevation range.