Mechanical and statistical analyses of 97 sediment samples reveal two dominant controls determining the resulting floodplain sedimentology.Firstly, the initial fine-grained loessial texture dominated the particle size of the early post-settlement alluvium, generally yielding fine-textured sediments across the valley bottom.Aggrading Streams are generally found above the line of best fit on this graph, and degrading Streams below that line.
The reach has downchannel length L, and base level is allowed to rise at a specified rate at the downstream end.
Diagrammatic cross section of an aggraded valley in which the stream shifted its course many times in the process of aggradation, as depositing streams are known to do.
The coarser materials in the various positions, from below upward, represent the successive sites of the channel, two channels being represented in the last stage.
Further landscape de-stabilization promoted upland gullying into coarser-textured residuum below the loess, with a concomitant particle size increase in the foodplain alluvium.
Thus, the resulting foodplain stratigraphy exhibits a coarsening upward sequence.
In theory, for restoration work, the Schumm graph could help identify design width and depth data for optimal stability.
High-resolution seismic reflection data are used in the identification of the stratigraphic succession filling Naples Bay, a tectonically active half-graben located in the extensional margin of the eastern Tyrrhenian Sea.
This program computes the time evolution toward steady-state aggradation.
The calculation assumes a specified, constant Chezy resistance coefficient Cz and floodplain width Bf. All sediment transport is assumed to occur in a specified fraction of time during which the river is in flood, specified by an intermittency.
Classification of stability is difficult considering the complexity of FGM processes and the sensitivity of channel evolution to initial conditions.
Schumm (1960) demonstrated that stability could be inferred from analysis of Stream Bankfull Width to depth ratios and the percent of silt and clay in the channel bank and bed boundary.