Hidrológiai Közlöny, 2017 (97. évfolyam)
2017 / 3. szám - MANAGING ENVIRONMENTAL RISKS - FLOOD PROTECTION EXPERIENCES AND COOPERATION IN THE DANUBE RIVER BASIN - Engi Zsuzsanna: Flood hazard modelling of the River Mura based on the silting up processes of the inundation area
94 Hidrológiai Közlöny (Hungarian Journal of Hydrology) 2017. 97. évf. 3. sz. Figure 18. Comparison of meander belt areas in different periods (left) and the details of the narrowed inundation area (A and B) with the meanders (right) Figure 19. Flood protection dykes and bank protections from the profile km 48+472 to km 0+000 of the Mura river (left) and the path of the river during the First Military Survey, which crosses the dykes in some locations (right)- dykes- bank protections- path of the river in 1785- path of the dykes SUMMARY In this brief overview of my doctoral dissertation, the main results of the research work were shown. In the dissertation, the flooding and silting up process of the inundation area of downstream sections of the meandering river Mura were studied. The results of different research methods were compared (hydraulic modelling, geomorphological methods, sedimentological analyses, dating of the layers in the sediment sample) in order to evaluate the possible effect of the changes in discharge on the flood hazard due to climate change. The silting up processes in the experimental area of the River Mura were studied using two research methods: sedimentological analysis and hydraulic modelling. On the basis of sedimentological analysis and the age of the sediment layer samples, the speed of the silting up process in the inundation area was calculated and compared with similar silting up values of other inundation areas. The conclusion is that this research method could be used for forecasting long-term silting up processes. For the purpose of 2D hydraulic modelling, the MIKE 21 FM program was introduced. The travel zones in the flood-plain forming during the travel time of the flood wave were determined by using 2D hydraulic modelling. Flood maps from hydraulic modelling were also produced. We tried to simulate the effect of flash floods using three types of synthetic flood waves. The flooded status of the inundation area was compared during the flood peak and the falling limb of the flood wave in order to gain information about the changes of the riverbed and the silting up of the inundation area. The data were compared and the process was described in detail and presented on figures and flood maps which constitute annexes of the dissertation. For the purpose of hydraulic modelling the silting up process, the MIKE 2D FM ST program was used. The basic data were taken from previous flood simulations. Results of the simulations provided information about the changes in the riverbed, the silting up or erosion processes of the inundation area and about bar locations. Because such research work has not been carried out on this downstream section of the Rriver Mura, the results were evaluated on the basis of measured silting up values after previous floods. The geomorphological characteristics of the meandering outfall river sections were also studied. By using GIS methods, changes in the riverbed of the River Mura over the past 250 years were reconstructed in the dissertation. The main point of the method is that we can forecast future changes in the riverbed by projecting the lines of different ages ontoeach other. By using this method, it is possible to separate and date/periodise anthropogenic influences.
