ESTIMATED CHARACTERISTICS OF THE MAXIMUM RUNOFF OF SPRING FLOOD OF THE RIVERS IN THE SOUTH OF UKRAINE

Abstract

The article presents a modern approach to forecasting and calculating the characteristics of the maximum flow of spring flood, cartographic synthesis of hydrometeorological characteristics in order to provide early warnings of catastrophic floods and prevent of emergencies, in particular, reducing the devastating effects of catastrophic flooding, ensuring accident-free ice drift and floodwater.

For operational and simplified work, an action algorithm of using the proposed approach has been developed - a territorial method of long-term forecasting of the characteristics of the maximum runoff of spring floods of lowland rivers in the south of Ukraine (on the example of the rivers of the Pivdenny Buh basin, rivers in the north-western part of the Black Sea Lowland, the Danube region and the Lower Dnieper region).

The method is based on the previous qualitative forecast of the type of river water content in the spring 
period of the year using discriminant analysis and the establishment of expected characteristics first in the form of their modular coefficients (for their spatial generalization), and then the quantitative values of runoff depths and maximum water discharge. The latter is achieved on through the scientific basis of the hydrological calculation of the basic parameters of the forecast scheme - average long-time annual runoff depths and maximum water discharge of spring water.

In addition, when establishing the average long-time annual runoff characteristics in the forecast scheme, it is proposed to introduce regional corrective factors that take into account changes in the water content of the spring flood in the rivers of the considered territory with a pronounced declining trend in recent years.

Prognostic map-diagrams built in the operational mode of forecasting gave an opportunity to estimate the size of the water flood immediately on a large part of the south of Ukraine, to carry out an analysis of the hydrometeorological situation in the basins and the region as a whole, to identify the probabilistic characteristics of the current year's flood.