I am excited to see our new paper on alluvial channel response to environmental perturbations published today in Earth Surface Dynamics. In this paper we present results from physical experiments of channels that were subject to perturbations of water and sediment discharges. We demonstrate that combining terrace geometries with information on (1) the timescales of terrace formation and/or (2) the sediment discharge from the river system, allows to distinguish between water and sediment discharges as the driver for river incision.
Tofelde, S., Savi, S., Wickert A.W., Bufe, A., Schildgen, T. (2019). Alluvial channel response to environmental perturbations: Fill-terrace formation and sediment-signal disruption. Earth Surface Dynamics, 7(2), 609-631. Journal Link
This is a schematic diagram of the changes expected in (a&b) river morphology and (c-f) the sediment output from an alluvial river during a transient phase of incision (a, c & e) or aggradation (b, d & f). Panels (c-f), show the upstream sediment input (orange line) and water input (blue line) and the downstream sediment output (colored circles). Importantly, a phase of incision can be due to a decrease in the sediment input into the channel, or an increase in the water input. The topography is similar in both cases but the pattern of sediment output is very different. Therefore, using sedimentary archives that record such sediment output together with terrace records can yield more information about the driver behind a change than each one of the records by itself.
