Chapter 9 Sec. 2

1. Chapter 9 Sec. 2 Stream Development

2. Moving Water • Adequate supply of water • What happens to streams in areas of high precipitation? • What happens to streams in areas of low precipitation? • The region where water first accumulates is known as what? • Headwaters • Where are common areas for head waters?

3. Stream development • As water accumulates in high in small gullies, water starts to move downward • Stream channel • narrow pathway into sediment or rock that the moving water carves • The moving water is held in by ___________, the ground bordering each side.

4. Stream development • The process by which small streams erode away soil and rock ahead of the stream is called ______________ • What does head ward erosion do to the stream? • Lengthens • What is stream capture?

5. Stream Valleys • As streams erodes – creates a V-shaped valley • Grand Canyon • Continues until it reaches a base level: elevation where it enters another stream • Lowest base: Sea Level

6. Meandering Stream • Streams slope decreases as it reaches base level, as result, the channel gets wider. Why? • Creates build up in the stream and erodes the sides of the channel • Starts to bend or wind called a Meander • Velocities of the water differ from where it is located within the stream. • Outside – greatest velocity • Inside – slowest velocity • Diagram

7. Deposition of sediment • Streams lose velocity – lose the ability to carry sediment • Alluvial Fan: • Sloping depositional features from bases of slopes • Sand or gravel • Death Valley • Delta: • Triangular deposit into larger, quieter bodies of water • Silt and clay • Mississippi River

8. Age of streams • Youth, Mature, Old • Rejuvenation: “to make young again” • Stream actively resumes down cutting towards its base level • Causes the channel to become V-shaped and start over