A Sand-Gravel Gilbert Delta Subject to Base Level Change

Laboratory experiments were conducted on a sand-gravel Gilbert delta to gain insight on its dynamics under varying base level. Base level rise results in intensified aggradation over the topset, as well as a decrease in topset slope and topset surface coarsening, the signals of which migrate in an upstream direction. Preferential deposition...

Armor breakup and reformation in a degradational laboratory experiment

Armor breakup and reformation was studied in a laboratory experiment using a trimodal mixture composed of a 1mm sand fraction and two gravel fractions (6 and 10mm). The initial bed was characterized by a stepwise downstream fining pattern (trimodal reach) and a downstream sand reach, and the experiment was conducted under conditions without...

A new technique for measuring the bed surface texture during flow and application to a degradational sand-gravel laboratory experiment

We present a new image analysis technique for measuring the grain size distribution (texture) of the bed surface during flow in a laboratory experiment. A camera and a floating device are connected to a carriage used to take images of the bed surface over the entire flume length. The image analysis technique, which is based on color segmentation...

A laboratory experiment on the evolution of a sand gravel reach under a lack of sediment supply

A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. A bed composed of a bimodal sediment mixture was installed with a uniform slope and an gradual fining pattern. At the upstream end of the flume the initial bed consisted of 100% gravel, which decreased stepwise (10% steps) in...

Size stratification in a Gilbert delta due to a varying base level: Flume experiments

Image analysis for measuring the size stratification in sand-gravel laboratory experiments

Measurements of spatial and temporal changes in the grain-size distribution of the bed surface and substrate are crucial to improving the modelling of sediment transport and associated grain-size selective processes. We present three complementary techniques to determine such variations in the grain-size distribution of the bed surface in sand...

New laboratory techniques to determine the grain size distribution of a sandgravel bed surface and substrate (abstract)

Grain size changes in a river dominated by mixed sediment are the outcome of sedimentary grain sizeselective processes. Progress in the measurement techniques that define the spatial and temporal variation in grain size is necessary to provide new insights in this field. Techniques as image analysis and acoustic methods have emerged in the last...

Laboratory experiment of a mixed-sediment Gilbert delta under varying base level (abstract)

Laboratory measurements to determine the grain size distribution of the bed surface and substrate (poster)

Image analysis techniques used to determine the grain size distribution of a sand-gravel bed surface and substrate