River bifurcations: Experimental observations on equilibrium configurations
Article first published online: 30 OCT 2007
Copyright 2007 by the American Geophysical Union.
Water Resources Research
Volume 43, Issue 10, October 2007
How to Cite
2007), River bifurcations: Experimental observations on equilibrium configurations, Water Resour. Res., 43, W10437, doi:10.1029/2007WR005907., and (
- Issue published online: 30 OCT 2007
- Article first published online: 30 OCT 2007
- Manuscript Accepted: 2 AUG 2007
- Manuscript Revised: 27 JUN 2007
- Manuscript Received: 23 JAN 2007
- River bifurcations;
- fluvial morphodynamics;
- morphodynamic influence
 In this work we have investigated the equilibrium configurations of a Y-shaped fluvial bifurcation through a laboratory analysis. Three series of experimental runs have been performed in a wide flume, where a symmetrical bifurcation has been constructed joining three branches with fixed banks and movable bed made of a well sorted quartz sand; the angle between the two downstream distributaries was equal to 30 degrees. The experiments have been carried out with different values of longitudinal bed slope and water discharge, in order to investigate a range of the relevant morphodynamic parameters typical of gravel bed braided rivers. The equilibrium configuration of the bifurcation has been characterized through the measure of the discharge partition in downstream branches and of the local bed structure at the node. The existence of unbalanced equilibrium configurations has been observed and the role of migrating alternate bars has been pointed out. The experimental results confirm the theoretical predictions which have been recently obtained through the simple model of Bolla Pittaluga et al. (2003). Moreover, interpreting the measured data in the light of the concept of morphodynamic influence provides a new perspective in the analysis of the equilibrium configurations of a bifurcation.