Sediment Movement in Alluvial Rivers - River Dynamics and Integrated River Management - page 308

of the secondary cells in association with, and as a consequence of, the developing bed forms. With pool
development alternating from one side of the channel to the other, a link to meander initiation is provided.
The riffle and pool sequence is linked with meandering based partly on the fact that the spacing of 5 to
7 times the channel width is approximately half the straight-line meander points in meanders, namely
Fig. 5.45 Regular meandering thalweg bed developed within a channelized stream in Yunnan, China (See color figure
at the end of this topic)
Fig. 5.46 Models of flow structure and associated bed forms in straight alluvial channels. (a) the Einstein and Shen
(1964) model of twin periodically reversing, surface convergent helical cells; (b) the Thompson (1986) model of
surface-convergent flow produced by interactions between the flow and mobile bed, creating riffle-pool units of
alternate asymmetry. Black lines indicate surface currents, and white lines near bed currents (after Knighton, 1998)