A comprehensive field analysis of a river confluence

A confluence zone of two rivers of different sizes was chosen to study the complex flow and morphological features with up-to-date measurement techniques. The main stream is River Danube with a mean flow of 2000m(3)/s, an average depth of 6m and an average width of 500 m, which approaches the junction zone in a sharp bend. The second river is a tributary of the Danube, River Hron with a mean discharge of 60m(3)/s, an average depth of 2m and an average width of 50 m, entering with an almost perpendicular course the main river. A detailed bathymetry survey, an intensive flow survey with fixed and moving ADCP, laser-based suspended sediment measurements and bed material sampling proved the interaction between flow, sediment and morphological conditions as shown by e. g. bed shear stress vs. d(90) grain size of bed material and longitudinal dispersion coefficient distribution vs. suspended sediment concentration.