Stream Erosion

1. Stream Erosion Notes

2. Watershed • A major river or stream along with all the smaller streams that connect to it.

3. Tributary • A small stream that feeds a larger river.

4. Streams/Rivers • Streams/rivers are running channels of water that begin at high elevation (source) and run to low elevations (mouth).

5. Stream terms • Stream Velocity: Speed of water in a stream. • Discharge: The volume of water in a stream. • Erosion: The ability of a stream to carry and remove sediment. • Deposition: When a stream deposits sediment because the velocity slows down. • Gradient: The steepness of the slope of the stream channel.

6. Relationship of Terms • As gradient increases velocity ________.

7. Relationship of Terms • As gradient increases velocity increases. • As gradient increases erosion ________.

8. Relationship of Terms • As gradient increases velocity increases. • As gradient increases erosion increases. • As discharge increases velocity ________.

9. Relationship of Terms • As gradient increases velocity increases. • As gradient increases erosion increases. • As discharge increases velocity increases. • As discharge increases rate of erosion _________.

10. Relationship of Terms • As gradient increases velocity increases. • As gradient increases erosion increases. • As discharge increases velocity increases. • As discharge increases rate of erosion increases. • As velocity decreases rate of deposition _________.

11. Relationship of Terms • As gradient increases velocity increases. • As gradient increases erosion increases. • As discharge increases velocity increases. • As discharge increases rate of erosion increases. • As velocity decreases rate of deposition increases.

12. Life-stages of streams • Youthful stream: • Very steep slope. • V-shaped channel. • Steep canyon walls. • Straight channel. • High velocity. • High rate of erosion.

13. Youthful Stream

14. Youthful Stream

15. Youthful Stream

16. Mature stream • The v-shape channel becomes more rounded. • Gradient is decreasing. • Velocity is decreasing. • Meanders begin to form. • A narrow flood plain begins to form.

18. Mature Stream

19. Old-age streams • Slow velocity. • Very wide flood plain. • Elaborate Meandering Patterns • Oxbow Lakes

20. Old-Age Stream

22. Stages in a stream

23. Oxbow Lakes

24. Oxbow Lakes

25. Oxbow Lakes

26. River Delta • When a moving river reaches its destination, the river’s speed will decrease sharply. • This sharp decrease in velocity will cause an enormous amount of deposition to occur. • This depositional feature is known as a delta, named for the Greek letter shaped as a triangle.

27. Mississippi Delta