Hydrological analysis of floods for the Krka River catchment

V magistrski nalogi smo analizirali povezave med posameznimi spremenljivkami in poplavami na porečju Krke. Raziskali smo odnos med padavinami, odtokom, volumnom površinskega odtoka, predhodno namočenostjo tal, vegetacijo ter izračunali koeficient odtoka. Z različnimi analizami smo prišli do zaključkov, kaj je glavni razlog za nastanek poplav na obravnavanem porečju in kdaj te običajno nastopijo. V teoretičnem delu smo predstavili vrste poplav v Sloveniji in njihove značilnosti, v nadaljevanju pa predstavili tudi samo porečje Krke, ter metodologijo dela. Analize v praktičnem delu magistrske naloge smo razdelili na dva dela. Prvi del predstavlja analizo obdobnih statistik, kjer je narejena analiza mesečnih ekstremov v obdobju meritev, analiza letnih konic po mesecih ter primerjava največjih specifičnih odtokov na porečju. Drugi del predstavlja analizo glavnih padavinskih dogodkov, kjer smo se osredotočili na pripadajoče visokovodne valove in njihove volumne ter koeficiente odtoka. Rezultati kažejo, da je največji poplavni dogodek na porečju Krke nastopil leta 2010, ko so pretoki Krke presegali 100-letno povratno dobo, največja vrednost pretoka na vodomerni postaji Podbočje pa je znašala 468,2 m3/s. Največjim volumnov valov smo bili priča v visokovodnih dogodkih nov./dec. 2005 in okt./nov. 2015. Največji koeficienti odtoka na porečju Krke običajno nastopijo na vodomerni postaji Soteska, najmanjši pa na vodomerni postaji Prečna.The master thesis presents the analysis of relationships between individual variables and floods in the Krka River catchment. The relations among precipitation, runoff, runoff volume, antecedent soil moisture and vegetation were analysed. Also, the runoff coefficient was calculated. The various analyses pointed out the reasons behind the occurrence of floods in the designated catchment and the periods they usually occur in. Different types of floods in Slovenia and their characteristics are presented in the theorethical part of the thesis. Additionally, the Krka River catchment and the methodology used are described. The analyses in the practical part of the thesis are divided into two parts. The first part presents the analysis of periodical statistics, which consists the analysis of monthly extremes in the period of measurements, the analysis of annual flood peaks by months and the comparison of the largest specific runoffs in the river catchment. The second part of the analysis presents the analysis of the largest precipitation events with the emphasis on the corresponding flood waves, their runoff volumes and the runoff coefficients. The results show that the largest flood event in the Krka River catchment occurred in 2010, when discharge exceeded the return period of 100 years. The highest discharge measured at the Podbočje gauging station was 468.2 m3/s. Flood waves with the highest volumes occurred during the events November/December 2005 and October/November 2015. The highest runoff coefficient usually occurs at the Soteska gauging station and the lowest at the Prečna gauging station