Geology Reference
In-Depth Information
Braided streams
Braided channel patterns, or
braided streams,
occur when a stream's flow is separated
into multiple channels that weave back and forth, intertwining with one another. The
channels are separated by mounds or
bars
of sand and gravel (that sometimes have
trees and other plants growing on them). This pattern is illustrated in Figure 12-5.
Braided streams are most common when streams have very high inputs of sediment but
move slowly so that most of the sediment is deposited, creating the sand and gravel
bars. They are most often found on flat or gently sloping land surfaces.
Figure 12-5:
A
braided stream
channel.
Meandering streams
A stream that flows in a single channel but winds its way across land like a snake is
called a
meandering stream.
Meandering streams move back and forth across a relatively
flat surface, creating loops. The continued removal and deposition of sediment in mean-
dering streams may eventually cut off a loop from the main channel, creating an
oxbow
lake,
as illustrated in Figure 12-6.
Oxbow lakes are created because of the way the stream's flow speed (velocity) changes
as it twists and bends around the curves.
Within any stream the velocity is greater on the outside edge of a turn, which
means the outside edge picks up or erodes more sediments. Velocity is slower on
