Alluvial cover controlling the width, slope and sinuosity of bedrock channels

Downstream variations in the width of bedrock channels

Field surveys of channel width w and drainage area A in bedrock channel reaches reveal relationships where w 5 cA, similar to the classic hydraulic geometry of alluvial channels. Data from five mountain channel networks support the assumption used in many landscape evolution models that an alluvial hydraulic geometry relationship where b 5 0.3–0.5 holds for bedrock channel systems. Although the...

Evaluating the controls of shear stress, sediment supply, alluvial cover, and channel morphology on experimental bedrock incision rate

[1] We explored the dependence of experimental bedrock erosion rate on shear stress, bed load sediment flux, alluvial bed cover, and evolving channel morphology. We isolated these variables experimentally by systematically varying gravel sediment flux Qs and water discharge Qw in a laboratory flume, gradually abrading weak concrete “bedrock.” All else held constant, we found that (1) erosion ra...

The lowermost Mississippi River: a mixed bedrock-alluvial channel

In this study, the distribution of channel-bed sediment facies in the lowermost Mississippi River is analysed using multibeam data, complemented by sidescan sonar and compressed high-intensity radar pulse seismic data, as well as grab and core samples of bed material. The channel bed is composed of a discontinuous layer of alluvial sediment and a relict substratum that is exposed on the channel...

Modeling and Estimating the Dimensions of Stable Alluvial Channels using Soft Calculations

In this research, soft computational models including multiple adaptive spline regression model (MARS) and data group classification model (GMDH) were used to estimate the geometric dimensions of stable alluvial channels including channel surface width (w), flow depth (h), and longitudinal slope (S) and the results of the developed models were compared with the multilayer neural network (MLP) m...

The Role of Sediment in Controlling Steady-State Bedrock Channel Slope: Implications of the Saltation-Abrasion Incision Model