Water Erosion

1. Water Erosion

2. Water is responsible for a majority of all erosion on Earth • Runoff- after rain the water remaining on the surface is called runoff. • As runoff moves downhill, it forms small grooves called ___________________. • As the rills flow into each other they form ________________________. • Water continues to flow downhill and becomes streams and rivers.

3. 5 Factors that effect runoff • 1. Amount of ________________. • 2. Amount of ___________________. • 3. Type of ______________________. • 4. Shape of _____________________. • 5. How land ____________________.

4. MORE RUNOFF = MORE EROSION!

5. River Systems • River systems start off with streams feeding into rivers, then rivers feeding into larger rivers. • Any stream or river that feeds into a larger river is called a ____________________. • The land area from which a large river and all of its tributaries collect is called a ______________________.

6. Erosion by Rivers • Through erosion rivers create valleys, waterfalls, flood plains, meanders and oxbow lakes. • Rivers often begin in hilly or mountainous areas and flow fast and straight. • Rivers slow down as land flattens out and create ____________________. • A flood plain is a wide flat area along a river where excess water flows during a flood.

7. When a river slows down it often creates a ______________, a loop like bend. • If a meander gets cut off from the river, it forms an _____________________. • When a river slows down it deposits sediment. • If a river flows out of a mountain valley and deposits the sediment it is called a _______________. • A _______________ is created when a river flows into a still body of water, (a lake sea or ocean)

8. This constructive process creates deltas and alluvial fans: A. erosion B. weathering C. deposition D. mass movement E. I don’t know

9. When a river stream meander becomes pinched off a(an) _______ forms. A. delta B. meander C. alluvial fan D. oxbow lake E. I don’t know

10. You would expect a youthful river to produce: A. V-shaped valley B. large deltas C. many oxbow lakes D. large alluvial fans E. I don’t know

11. Enrichment • Students will draw a picture of a river system; they must include the following: • deltas, • alluvial fans, • meanders, • and oxbow lakes. • Trade and identify a partner’s picture.