Calculation Approaches of the Probable Maximum Discharge of Spring Flood at Ungauged Sites in the Southern Buh River Basin, Ukraine

Abstract

Abstract Calculation of probable maximum discharge of spring flood are the great practical importance, since it is the basis to plan and design of different hydraulic structures, such as dams, culverts, urban and agriculture drainage systems, etc. Thus, the updating of the methodical approaches and parameters of the empirical formulas which using in the determining of the probable maximum discharge of spring flood at ungauged sites of the river basin is an actual task. In this paper for the Southern Buh River Basin were updated the parameters of the reduction formula and the limiting intensity formula of streamflow which are using to calculated of the probable maximum discharge of spring flood at ungauged basin in Ukraine. The presented results illustrate that parameters of empirical formulas that were calculated according to modern observation series (since the beginning of the observations to 2010) in comparison with previously received (since the beginning of the observations to 1980) have significant changes. We found out that it is due to cyclical of the long-term fluctuations of the maximum streamflow of spring flood in the Southern Buh River Basin. We also illustrated that for the small ungauged basins have the difficulties with the choice of rivers-analogues.