STUDENT EXPERIMENTS IN SEDIMENT TRANSPORT, LANDFORM MIGRATION, AND CHANNEL MODIFICATION IN NONCOHESIVE RIVER CHANNELS USING A LARGE SCALE LABORATORY STREAM MODEL

Geomorphologic experiments conducted during short-term laboratory activities using an Emriver Em4 river model (4 m x 1.5 m) have shown promising results in replicating stream patterns and in the observation of landform migration and sediment transport on streams. This stream table has an adjustable standpipe at the model’s downstream end that allows for base level changes, and variation of the table’s tilt angle permits the simulation of changes in stream behavior due to processes such as uplift or tectonism, and evolution of delta systems.

Sets of two-hour experiments were designed for students to observe a stream response to base level changes, and tectonism. During the exercises, students replicated straight and meandering stream patterns, and observed sediment movement along the channel; also, they examined sediment redistribution along meander bends and point bars. Changes in stream bed elevation were measured along three fixed cross-sections; these allowed for determining shifting of sand bars and alluvial terraces after modification of base level or axis tilt. To replicate tectonism, the lateral inclination of the table was modified, causing re-routing of the stream followed by channel scouring and formation of alluvial terraces. Furthermore, upon adjustment of the axial tilt, changes in the stream channel extended from lower reaches to the middle of the simulated stream. After completion of formal exercises, students were encouraged and engaged into creating their own science experiments, thus increasing their curiosity on towards science projects.

Through these activities, students had hands on experience on the response of fluvial systems to natural and man made changes. The results obtained on these experiments demonstrate the advantages of using large scale movable bed river models to teach and demonstrate geomorphologic concepts in laboratory settings.