Variability of bed mobility in natural, gravel-bed channels and adjustments to sediment load at local and reach scales
Lisle TE, Nelson JM, Pitlick J, Madej MA, Barkett BL. 2000. Variability of bed mobility in natural, gravel-bed channels and adjustments to sediment load at local and reach scales. Water Resources Research. 36(12):3743-3755
This study was conducted by researchers from the Pacific Southwest Research Station, the U.S. Geological Survey, and the University of Colorado. Six channels were examined in northwestern California and western Colorado. From the Abstract: "Local variations in boundary shear stress acting on bed-surface particles control patterns of bed load transport and channel evolution during varying stream discharges. At the reach scale a channel adjusts to imposed water and sediment supply through mutual interactions among channel form, local grain size, and local flow dynamics that govern bed mobility. In order to explore these adjustments, we used a numerical flow model to examine relations between model-predicted local boundary shear stress (Tj) and measured surface particle size (D50) at bank-full discharge in six gravel-bed, alternate-bar channels with widely differing annual sediment yields. Values of Tj and D50 were poorly correlated such that small areas conveyed large proportions of the total bed load, especially in sediment-poor channels with low mobility. Sediment-rich channels had greater areas of full mobility; sediment-poor channels had greater areas of partial mobility; and both types had significant areas that were essentially immobile. Two reach-mean mobility parameters correlated reasonably well with sediment supply."
- Type
- Journal Article
- Authors
- Lisle, Thomas; Nelson, Jonathan; Pitlick, John; Madej, Mary; Barkett, Brent
- Units
- REDW
- Keywords
- Aquatic Studies, bed mobility, boundary sheer stress, Geology, gravel bed channels, Physical Processes, Redwood Creek, Rivers, Sediment Load, Streams, surface particles