Channel Types in Streams

want to erode down to the base level. A stream at equilibrium is known as a graded stream.

CHANNEL TYPES IN STREAMS

Streams can have a wide range of patterns or channel patterns. Some wander in a meandering way, while others are straighter. These are the main channel types you will see in any stream:

• Braided streams – these are streams that break down and come together in complex ways, especially when the gradients are low and the sediment is coarse.

Certain mountain or glacier streams can be like this.

• Straight channels – these have V-shaped valleys that are narrow and steeper gradients. They tend to be more rapidly flowing than other streams.

• Meandering streams – these are slower and curve back and forth. Remember that the water is fastest on the outer edge of the curve so you'll get a cut bank, which is an area of erosion where the meandering stream is trying to extend itself. The point bar is on the inner aspect of the loop, where there is added sedimentation.

Some rivers meander in deeply entrenched valleys or canyons. They started out on plateaus and cut through bedrock over millions of years. Meandering can get so extreme that it cuts off a segment of it to create a lake near the re-cut stream, called an oxbow lake. An oxbow lake is a former meandering channel. It can fill in with sediment over a period of time to make a meander scar.

Alluvial fans are landforms made from stream deposits. They fan out from the mouth of the stream into valleys from mountain canyons where the sediment just kept going until it met the slow moving valley floor. You often see these in drier regions of the world.