1. Erosion Weathered rock particles are transported Agents of erosion
The actual process doing the eroding
Gravity
Running water
Wind
Glaciers
Waves
Human activity
Gravity is the driving force behind most erosion

2. Erosion by Gravity Mass Movement Gravity pulls rock sediments downhill
Soil creep
Debris flow
Rock fall

3. Running Water Most common agent of erosion on Earth Stream Tributary
A flowing body of water confined to a channel
Tributary
A smaller stream that feeds into a larger one

4. Stream Valleys Streams carve out V-shaped valleys Watershed
The drainage area of a stream

5. Watersheds

6. Continental Divide
Argentina

7. Stream Velocity Determined by 3 factors: Gradient Discharge (Volume)
steeper= = faster
Discharge (Volume)
more discharge = faster
Shape of the channel
less contact with sides = faster

8. Velocity within a Stream
Velocity is not the same throughout the stream

9. Where is the fastest part?
Straight Stream
Fastest Part???
In a straight stream, the fastest part is in the middle slightly below the surface

10. Where is the fastest part?
Curved Stream
Fastest Part???
In a curved stream, the fastest part is on the outside of the curve and slightly below the surface

11. Importance of Stream Velocity
The faster a stream moves the larger sized particles it can carry

12. How a Stream Carries Sediment
Sediments can be carried in different ways:
Bouncing & Rolling
Suspension
Solution

13. Stream Stages
Youthful
Mature
Old Age

14. Stream Evolution Youthful Straight channel Narrow valley
Steep gradient
Rapids & waterfalls

15. Stream Evolution Mature Stream Not as straight Gradient not as steep
Little or no waterfalls & rapids

16. Stream Evolution Old Age Stream Features: Gradient & Velocity very low
Meanders
Oxbow Lakes
Floodplains

17. Meanders
meanders

18. Oxbow Lakes

19. Floodplains

20. Mature Stream

21. Mississippi River

22. River Delta
Where a stream enters a large body of water