Flow and suspended sediment dynamics at two large braid-bar bifurcations

R.N. SZUPIANY; J. HERNÁNDEZ; M.L. AMSLER

Santa Fe - Argentina

Simposio; 6th IAHR Symposium on River, Coastal and Estuarine Morphodynamics - RCEM 2009; 2009

Facultad de Ingeniería y Ciencias Hídricas - Universidad Nacional del Litoral

In this contribution, the evolution of flow structure and suspended bed material transport along two expansion-diffluence units in the Paraná River (Argentina) is described. Primary and secondary flow velocity components were measured with an acoustic Doppler profiler (ADP) at several cross sections properly arranged along the units. The moving-vessel mode was used. The backscatter signal of the ADP was calibrated to simultaneously record the suspended bed sediment concentrations. The sections were each surveyed five times in order to get reliable average values of the flow and sediment variables. The interactions between the flow and sediment variables particularly at the sections where channel expansion and flow bifurcation take place are presented. The role of relevant channel morphological features such as the deviation angles of the thalweg track on the main cores of flow and suspended sand concentrations is also analyzed.