BYUI Undergraduate Research Conference Abstract: Development of a sustainable migrating meander channel on a small-scale stream table

Abstract submitted for poster presentation at the BYU-Idaho Student Research Conference

Development of a sustainable migrating meander: Can a migrating and sustainable meandering stream channel be created on a small-scale stream table?

Brandon Rasaka, Cody MacCabe, Rachel McCullough, and William W. Little (mentor)

To date, generating an artificial sustainable and migrating meandering channel has been accomplished only on large-scale stream tables, such as that at the University of California - Berkley (>100 m²). However, using a new, smaller (~2 m²) table, designed by the BYU-Idaho Department of Geology and constructed in conjunction with the Department of Mechanical Engineering, that permits controlled changes in load type, load amount, discharge volume, and base level, we successfully accomplished this objective.

        

The challenge was finding a balance between cut bank erosion and point bar deposition, which, though conceptually simple, proved difficult to replicate in an artificial setting.  This was eventually accomplished by independently adjusting stream gradient, caliber and amount of load, flow velocity, discharge volume, base level, and cohesion of bank materials.  The key turned out to be using a mixture of sand and clay, both as the initial box-fill material and new sediment fed into the system. Clay in the box fill decreased the rate at which cut banks eroded.  Sand in the sediment feed allowed deposition of the initial point bar.  Clay in the sediment feed added cohesion to the point bar, decreasing likelihood of channel straightening through chute cutoff across the bar.

The final result was development of three meander bends that migrated both laterally and downstream, each with a well-defined cutback and well-developed point bar.