Fades Models
A
221
Fig. 8.28. Velocity patterns around two successive meander
bends of the Wabash River. The development of the spiral fl ow
pattern is demonstrated by the divergence in surface and bottom
flow vectors. Note the shifting of the position of maximum surface velocity across the channel, and the fact that this does not
impinge against the outer bank until half way around the Helm
bend. (Jackson 1976d)
B
0
.... ....... .... _,_,_, .. , _,_,_,_,_,_,_,_._,_._,_,_,_,_, __ ,_,_,_ .... . ., .... ,_._,_._,_,_,_ ,_ ....... .... .... .... . _. ... . ... . ... ....... ...... 0
·'
• flOW OIRECT!ON
'
�
:1 ·'
:E
•0
r
�
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'
"
:E
· 6
4< CROSSOVER <2>
-+
POINT BAR 2
.P.
.a
0
Fig. 8.29. Pathometer trace through one meander wavelength of the upper Congaree River during bankfull discharge. Large dunes up to 2 m high occur on point-bar
SCALE
0
500
surfaces. Two sets of smaller-scale dunes are in dynamic
equilibrium in the relatively straight stretch betwen the
bends. (Levey 1978)