Runoff regime changes in the Slovak Danube River tributaries

This paper deals with a statistical analysis of changes in the hydrological regime of Slovak tributaries of the Danube River at 11 stations over two 30-year periods: 1931–1960 and 1986–2015. We analyzed changes in monthly discharges using the Pardé coefficient method, as well as changes in average daily discharges. The monthly Pardé coefficients may be used to plot so-called regime curves. Their course is essentially determined by the monthly water balances in the catchments, as well as by intra-annual storage effects like snow accumulation and snowmelt. Changes in the course of Pardé coefficients for water stations of Slovak tributaries of the Danube River do not show any major changes, except for the Ipeľ-Holiša and Topľa-Hanušovce stations. From the results of the daily flow rate analysis it is clear that the course of daily flow rates in the monitored stations remains unchanged during the year and in the most of the monitored Slovak stations the daily flow rates decrease, except for the water stations Belá-Podbanské and VáhLiptovský Mikuláš.