Where does a river get its water? • Where does this water ultimately come from?
Moving water is the major agent of erosion that has shaped Earth’s surface • Water can pick up soil particles and move them (erosion) or drop them off (deposition)
Water that moves over Earth’s surface is called runoff • Five factors that affect amount of runoff: • Amount of rain • Amount of plants • Type of soil • Shape of land • How people use the land
A gully is a large groove, or channel, in the soil that carries runoff after a rainstorm • A stream is a channel along which water is continually flowing down a slope • A tributary is a stream that flows into a larger stream
Erosion by Rivers • A river creates valleys, waterfalls, flood plains, meanders, and oxbow lakes • Rivers create “v-shaped valleys” • The flat, wide area of land along a river is called a flood plain
A bend in a river is called a meander • Sometimes a meander can be cut off to form an oxbow lake
Deposition by rivers • Deposition creates alluvial fans and deltas
Alluvial Fanwide, sloping deposit of sediment formed when stream leaves mountain
How can water move soil and sediment? • In what ways do rivers flow? • Where would you find a delta in the United States?