Sand dunes in the Paraná River

AMSLER, MARIO; PRENDES, HÉCTOR HUGO

Santa Fe, Argentina

Workshop; Workshop on Morphodynamic Processes in Large Lowland Rivers; 2007

Facultad de Ingeniería y Ciencias Hídricas (UNL) - National Center of Earth-Surface Dynamics (Universidad de Minnesota/USA) - Universidad de Illinois (USA)

ABSTRACT. A general description of the sand dunes found on the Paraná River bed differentiating between “large” and “small superimposed” dunes, is presented herein. The variations of their respective geometry (height, length and steepness) with the river discharge based on field measurements, are depicted. Observations concerning the bed forms velocity displacement and its relationship with the annual bed load transport, are included. Semi-empirical formulas to predict the dune height and velocity devised from basic principles of fluvial hydraulics and involving gross stream parameters easily measured in field, are also discussed. Finally, some results concerning theoretical topics related with dunes obtained combining field and laboratory experiments, are summarized. They involve the shape of flow velocity profiles along a large dune, the bed roughness height to be considered in the presence of dunes superimposition and the nature of form resistance in a large river when the coexistence of different scale dunes prevails. A general description of the sand dunes found on the Paraná River bed differentiating between “large” and “small superimposed” dunes, is presented herein. The variations of their respective geometry (height, length and steepness) with the river discharge based on field measurements, are depicted. Observations concerning the bed forms velocity displacement and its relationship with the annual bed load transport, are included. Semi-empirical formulas to predict the dune height and velocity devised from basic principles of fluvial hydraulics and involving gross stream parameters easily measured in field, are also discussed. Finally, some results concerning theoretical topics related with dunes obtained combining field and laboratory experiments, are summarized. They involve the shape of flow velocity profiles along a large dune, the bed roughness height to be considered in the presence of dunes superimposition and the nature of form resistance in a large river when the coexistence of different scale dunes prevails. A general description of the sand dunes found on the Paraná River bed differentiating between “large” and “small superimposed” dunes, is presented herein. The variations of their respective geometry (height, length and steepness) with the river discharge based on field measurements, are depicted. Observations concerning the bed forms velocity displacement and its relationship with the annual bed load transport, are included. Semi-empirical formulas to predict the dune height and velocity devised from basic principles of fluvial hydraulics and involving gross stream parameters easily measured in field, are also discussed. Finally, some results concerning theoretical topics related with dunes obtained combining field and laboratory experiments, are summarized. They involve the shape of flow velocity profiles along a large dune, the bed roughness height to be considered in the presence of dunes superimposition and the nature of form resistance in a large river when the coexistence of different scale dunes prevails. A general description of the sand dunes found on the Paraná River bed differentiating between “large” and “small superimposed” dunes, is presented herein. The variations of their respective geometry (height, length and steepness) with the river discharge based on field measurements, are depicted. Observations concerning the bed forms velocity displacement and its relationship with the annual bed load transport, are included. Semi-empirical formulas to predict the dune height and velocity devised from basic principles of fluvial hydraulics and involving gross stream parameters easily measured in field, are also discussed. Finally, some results concerning theoretical topics related with dunes obtained combining field and laboratory experiments, are summarized. They involve the shape of flow velocity profiles along a large dune, the bed roughness height to be considered in the presence of dunes superimposition and the nature of form resistance in a large river when the coexistence of different scale dunes prevails.