engleski

Analysis of ice regimes on the Danube in Dalj in 2012. and 2017.

The regime of ice in rivers represent the spatial and temporal regularity of occurrence in watercourses. In hydrological terms distinguish ice drift and a static ice. Ice regime of natural rivers is influenced by climate, water regime and channel morphology. Since channel morphology and water regime are influenced by river dams, changes in ice conditions can be expected. Regular ice phenomena observation mostly dates back to the 19th century. During this long-term observation period, the human impacts on the river hydrology and morfology have become more and more intensive. River ice regime could characterise by the date of drift-ice appearance, freeze-up, break-up and river ice disappearance, furthermore the duration of ice-affected and ice-covered season. Ice-on is the date of ice appearance, when ice drifting starts. Freeze-up is the date of continuous and immobile ice-cover occurrence. Breakup is the date, when the ice cover begins to move downstream and open water areas appear. Ice-off is the date of ice disappearance, when the river becomes ice-free. The Danube is the second length of the rivers in Europe, long 2857 km (188 km in Croatia). Flows through the nine European countries or is their border river. For the water regime of the Danube is characterized by big water level fluctuations. Danube freezes only for the strong winter, the lower course of the thickness of the ice is up to 60 cm. Therefore, navigation occasionally suspended from mid- December to early March. In this paper, we analysed the two ice regime on the Danube in Dalj in Croatia, recorded in 2012 and 2017. The consequence of ice on watercourses is to create backflow and reduce the flow profile, which can result in the appearance of ice floods. To prevent the appearance of ice floods on the Danube, the ice was broken by icebreakers, and in some places are mined with explosives.

ice regimes, Danube, Croatia, ice flood, icebreaker

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