Geoscience Reference
In-Depth Information
DISCOVER…
MISSISSIPPI RIVER MEANDERS
You can learn much about a river by examining satellite
images of it. This image provides an excellent example. It
is a synthetic aperture radar image of the Mississippi River
that was acquired on the space shuttle in October 1994. The
image is centered at about 32.75° N, 90.5° W and covers an
area of about 23 km by 40 km (14.2 mi by 24.8 mi). North
is toward the upper right of the image and water appears
black. The accompanying diagram shows the location of the
oxbow lakes and some of the meander scars. See if you can
find some more.
As you can see, the Mississippi River is actively
meandering in this area, with numerous oxbow lakes and
meander scars visible. By looking at such an image, you
can discover where the fastest and slowest velocities are
within the river. Note that two such places are identified on
the diagram. In addition, one can determine the areas that
are prone to flooding. For example, the elevation between
the current channel and the modern floodplain boundary is
probably low, which means that the area is likely to flood
during high discharge. The numerous signs of meandering
also mean that the Mississippi River must be close to base
level in this area and that the stream is in, or close to, a
graded condition.
Inside of meander
(lowest velocity)
Low ground
Mississippi
River
Island
Oxbow lake
Meander scars
Modern floodplain
boundary
Outside of meander
(greatest velocity)
(a) (b)
(a) The meandering Mississippi along the borders of Mississippi, Arkansas, and Louisiana. (b) Note the numerous oxbow lakes and meander
scars highlighted in the diagram.
