Related Experiment Video
Updated: Feb 6, 2026

Construction of a Low-cost Mobile Incubator for Field and Laboratory Use
Published on: March 19, 2019
Growth and shape of a laboratory alluvial fan
P Delorme1, O Devauchelle1, L Barrier1
1Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, UMR7154, 1 rue Jussieu, 75238 Paris Cedex 05, France.
Abstract:
Using laboratory experiments, we investigate the influence of water and sediment discharges on the morphology of an alluvial fan. In our flume, a single-thread laminar river deposits corundum sand into a conical fan. We record the fan progradation with top-view images and measure its shape using the deformation of a Moiré pattern. The fan remains virtually self-affine as it grows, with a nearly constant slope. We find that, when the sediment discharge is small, the longitudinal slope of the fan remains close to that of a river at the threshold for sediment transport. Consequently the slope depends on the water discharge only. A higher sediment discharge causes the fan's slope to depart from the threshold value. Due to the downstream decrease of the sediment load, this slope gets shallower towards the fan's toe. This mechanism generates a concave fan profile. This suggests that we could infer the sediment flux that feeds a fan based on its proximal slope.
More Related Videos
Related Concept Videos
Molecular Shape and Polarity
VSEPR Theory and the Basic Shapes
Molecular Shapes
Two regions of electron density in a diatomic...
First Derivatives and the Shape of a Graph
Second Derivatives and the Shape of a Graph
Population Growth

