Hydrological analysis of floods for the Ljubljanica river basin

Ljubljansko barje is the largest floodplain in Slovenia. Heavy rainfall in predominantly karst\ud catchment area of Ljubljanica river instigate flooding of Ljubljansko barje, caused by river\ud Ljubljanica and its torrential tributaries such as Iška at the south side and Gradaščica at the\ud north side of Ljubljansko barje. On the one hand, flooding of Ljubljansko barje is beneficial to\ud the city of Ljubljana as it lowers the risk of flooding in the city, while on the other hand, it\ud poses danger to the inhabitants of settlements of Ljubljansko barje. This thesis analyses\ud hydrology of the largest floods of Ljubljansko barje since the beginning of the 20th century,\ud such as floods in 1926, 1933 and 2010.\ud Analysis results indicate that flooding of Ljubljansko barje occurs in combination with highintensity\ud precipitation that lasts for couple of days. Flooding of this area can also occur after\ud longer periods of lower-intensity precipitation followed by precipitation of higher intensity due\ud to lower water retention capability of catchment area of Ljubljanica. Flooding of river\ud Ljubljanica on Ljubljansko barje initiate gradually and last for several days or even few\ud weeks. On the contrary, flash floods are characteristic of torrential tributaries Gradaščica and\ud Iška. Main causes of flooding of Ljubljansko barje are quantity and duration of precipitation\ud and high antecedent precipitation index. Results show that floodings of Ljubljansko barje\ud usually occur in autumn. Trends in seasonal precipitation and continuous settlement of the\ud ground of Ljubljansko barje indicate severer effects of flooding in this area in the future