Geology Reference
In-Depth Information
Progressive Migration with River Shrinkage
initial meander belt
minor change
in edge of
floodplain
A
Progressive Migration
major change in
edge of
floodplain
initial meander belt
progressive meander belt
migration through time
progressive meander belt
migration through time
B
initial meander belt
Meander-Belt Avulsion
Fig. 8.26
Models for responses of
meandering rivers to tilting across
the floodplain.
A. Steady tilting with shrinkage of river
size. B. Steady tilting and migration with
abandoned meanders typically facing in
the direction of tilting. C. Abrupt tilting
and avulsion across a floodplain.
Abandoned meanders face both toward
and away from tilt direction. Modified
after Alexander
et al.
(1994).
broad floodplain
meander scars facing both directions
avulsion to new meander belt
C
margin. When
T
=
0, the river is located near the
mid-line of the basin, whereas, as
T
→
1, the river
is shifted increasingly close to the basin's margin
(Cox, 1994). These ratios can be determined
from topographic maps and can be easily used
to provide a quick overview of potential zones
and directions of tilting within a drainage basin.
In the process of shifting, a meandering river
will abandon oxbows and meander bends, which
then remain as visible scars on the landscape.
