Young rivers have a V-shaped valley. They have few tributaries, flow quickly, and erode their channels deeper. They may have rapids or waterfalls.
Mature rivers are less steep than young rivers and flow more slowly. They usually have a U-shaped valley, a floodplain, and wind through the land in wide looping curves called meanders.
Old rivers are much wider than they are deep. They dominate the landscape and have large floodplains. They may change courses and leave behind C-shaped lakes called oxbow lakes.
