Water Erosion

Stream Development

As water in a stream moves along, it picks up sediments from the bottom and sides of its channel.  Water picks up and carries lightweight sediments, while the heavier sediments roll along the bottom of the stream channel. All the different materials scrape against the channel, where they continue to knock loose even more sediments. For this reason, a stream continually cuts a deeper and wider channel.

Stream Erosion

Streams

There are many different kinds of streams. They are classified into three categories: Young, Mature, and Old. Streams are not necessarily classified into these by age, but by their condition and livelihood.
Young streams flow swiftly through a steep valley and has steep sides. A young stream may have whitewater rapids and waterfalls.
The next stage of streams is mature streams. These generally flow less swiftly through a valley than a young stream would. Water in shallow areas of a mature stream is slowed down by the friction caused at the bottom of a river.
The last stage of streams is old streams. An old stream flows slowly through a broad, flat floodplain that it has carved. One example of an old stream is the lower Mississippi River.

By the ThinkQuest Team of Grant School

Photo courtesy of Rick Mitchell for the USGS

Photos courtesy of Rick Mitchell, of the Santa Cruz Beach Boardwalk, California