Morphological Investigation of a Critical Reach of the Upper Hungarian Danube

The aim of this study is to analyze the current morphological changes and to predict the potential future trends of a critical reach of the upper Hungarian Danube River. In this section of the river the morphological features have undergone significant changes, mainly due to human impacts, such as the construction of the Gabcikovo hydropower plant close to the Slovakian border, or the river regulation measures with groin fields along the Hungarian reach. The morphological changes of the river inherently led to river management issues, e.g. the developed gravel bars caused problems for inland navigation. In order to reveal and understand the characteristic morphodynamic processes, results from past bed geometry surveys were assessed, moreover, extensive field measurement campaigns were carried out, including bathymetry survey, flow survey with fixed and moving Acoustic Doppler Current Profiler (ADCP), bed material sampling and bedload measurements. The utilization of up-to-date field data processing methods provided essential information on the current dominant morphological processes and finally, suggestions were made on the stability of the river planform.