Migration of large dunes during extreme floods of the Paraná River, Argentina

SERRA, SG; VIONNET, CA

Urbana - Champaigne, Illinois, EE.UU.

Simposio; RCEM 2005 - 4th IAHR Symposium on River, Coastal, and Estuarine Morphodynamics; 2005

University of Illinois, IAHR

A commonly used method to estimate bed load transport rate is to track dunes migration. Then, whenever enough echo sounding records are available along the same profile on a sandy riverbed at successive periods of time, a simple formula provides the sought bed load rate. However, a dominant feature of the large dunes observed in the sandy bed of the Paraná River is the persistent presence of wavelets migrating on top of their carrier sand waves. These larger dunes may present steep-slope fronts, or occasionally, low-slope fronts. In this work, a methodology is used to quantify the bed load transport associated with a hierarchy of migrating bedforms, following ideas borrowed by the Russian school. This approach is applied to the echo sounding records that show the riverbed evolution of the Paraná River in Argentina during few days of the extreme floods of 1983, 1992, and 1998