1. A.Erosion – The transportation of weathered sediments 1. Agents of Erosion or Transport Systems: a. Running water b. Wind c. Glaciers d. Waves & Tidal Surges e. People GRAVITY 2. Driving force of erosion: GRAVITY

2. B. EROSION BY RUNNING WATER 1. Transport of Stream Sediments can be… a. dissolved salts in solution b.in a suspension c. carried by rolling,bouncing, sliding, or floating. Clay particles called "Colloids" do not settle to the bottom of a stream.

3. The rate of Erosion: Determined by the velocity of a stream. 1. Gradient: slope of the land A steeper slope has a greater rate of erosion.

4. 2.Volume of discharge: (Water added to the stream) Rain or Snow Groundwater Tributaries Increase Stream Velocity A greater amount of discharge increases the rate of erosion.

6. Tributaries Increasing Stream Flow. Q A

7. 3. Channel Shape: Narrow channels have less surface area and reduce the friction on the water Velocity Increases. Streams create V- shaped valleys

8. 4.Sediment Size and Stream Velocity As the velocity of the stream increases the size of the sediments that can be moved increases. Graph shows the velocity needed to maintain movement of a sediment, but not to start.

9. Stream Development: Youthful: Steep Gradient / High Velocity / Erosion Dominate  Low Volume of Water Mature: Moderate Gradients & Velocity  Depositional & Erosional forces are in balance w/ flood plains Old: Gentle Gradients / High Velocity / Deposition Dominate  Large Volume of Water

10. A Youthful Stream Narrow V-shaped Downcutting Swift water Steep gradient Erosion is dominant

11. Mature Stream Lateral Erosion begins Meanders develop Floodplains develop Gradient lowers

12. Old Age Wide meanders and oxbow lakes Wide floodplain Low velocity Low gradient Dynamic equilibrium between erosion and deposition

13. 3. The differing points of velocity within the stream. Depends on channel shape, meanders, and surface friction. A. Straight Channel:  Velocity greatest below the surface @ center.

14. B Meandering Channel: Velocity greatest on outside of curve  Resulting in more erosion. Velocity decreases on inside curve  Resulting in deposition.

16. Velocity Controlling Erosion & Deposition

17. Erosion

18. Meanders Found in Old Streams Low Velocity & Gradients Deposition Dominate Oxbow Lakes Flood Plains

19. Mississippi Floods Pink are Metropolitan Areas

20. Mississippi Delta Deposition Dominate

21. C. EROSION BY GLACIERS 1. Glaciers moved by gravity. 2. Ice actually flows (plasticity). 3. Velocity greatest in the center. 4. Form U-shaped Valleys

22. GLACIAL Movements Flow is always from High to Low elevation.

23. U- Shaped Valleys After Glacial Retreat Slightly Filled in with Deposition Slightly Filled in with Deposition

24. D. Erosion by Wind 1. As wind velocity increases the size of the particles carried will increase.

26. E. FEATURES OF ERODED SEDIMENTS 1.Streams: Round and smooth 2. Wind: Angular Sediments 3. Glacial: Rounded with scratched surfaces called striations indicating direction of ice flow. 4. Gravity: Produces sharp angular features from the break during the fall.