Sediment transport and bed topography for unsteady hydrograph flows in a laboratory flume

Authors: Wren, Daniel; Kuhnle, Roger; Langendoen, Eddy; MCALPIN, TATE - Us Army Corp Of Engineers (USACE)

Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2023
Publication Date: 6/26/2023
Citation: Wren, D.G., Kuhnle, R.A., Langendoen, E.J., Mcalpin, T. 2023. Sediment transport and bed topography for unsteady hydrograph flows in a laboratory flume. Meeting Proceedings. Proceedings.

Interpretive Summary: Abstract Only.

Technical Abstract: Sustainable management of watersheds is facilitated by accurate predictions of the rate of sediment transport in streams. Transport relations for sediment in streams were typically developed with assumptions of steady-state conditions with the be assuming that the flow of water in the stream was steady and uniform. Yet, it has been established in previous research that sediment transport rates and bed topography are strongly affected by unsteady flows. During changing flows, bed topography and flow may never reach equilibrium values; rather, they continue to change out of phase with one another, creating a complex system that is particularly difficult to understand and predict. Relative to unsteady flows over gravel, less research effort has focused on sand-bedded channels and the evolution of sand bed forms in response to unsteady flow conditions, and even less research has combined measurements of sand transport rate with detailed topographic measurements to arrive at a quantitative, comprehensive picture of the process of adjustment. We will report on a series of experiments in which flow hydrographs ranging from 1 to 6 hours long were applied to a sand bed in a laboratory flume while collecting real-time measurements of bed topography, sediment transport, and water-surface slope.