Statistical Analysis and Trend Detection of the Hydrological Extremes of the Danube River at Bratislava

Abstract

The territory of the Danube River Basin is one of the most flood-endangered regions in Europe. The flow regime conditions of the Danube River are continually changing. These changes are the result of natural processes and anthropogenic activities. In the present study, we focused on the statistical analysis and trend detection of the hydrological extremes of the Danube River at Bratislava. This paper firstly analyses the changes in correlation between water levels of the Danube River at Bratislava and Kienstock. Studied period of 1991-2013 included one or three hour measured water levels of the Danube River at Bratislava and Kienstock and shorter periods (1991–1995, 1999–2002, and 2004—2013) were selected for identification of the water level changes at Bratislava. One of the factors that recall the necessity to establish empirical - regression relationships was increasing of water levels of the Danube River at Bratislava (due to sediments accumulation at Bratislava). The results of the analysis indicated an increasing of water levels corresponding to the same flood discharges observed in the past. We also can say that travel time of the Danube floods between Kienstock and Bratislava did not change significantly during the analysed period. In the second part of the paper, we have identified changes in commonly used hydrological characteristics of annual maximum discharges, annual discharges and daily discharges of the Danube River at Bratislava during the period of 1876–2019. We examined whether there is a significant trend in discharges of the Danube River at Bratislava.