1. Running
water

2. The Hydrologic Cycle

3. PARTS OF A STREAM Channel - path of river Bed - bottom
Head - beginning/source
Mouth - ending
Gradient - steepness of slope
Base level - lowest point to which a stream erodes (ocean, another river, lake) ultimately the oceans

4. Longitudinal profile of a stream
Channel
Base level

5. A drainage basin is the land area that contributes water to a stream.
A divide is an imaginary line that separates the drainage basins of one stream from another.

6. Mississippi River Drainage Basin

7. Drainage Patterns
Radial
Dendritic
Trellis
Rectangular

8. Dendritic Drainage

9. What streams do… Erode Transport Material Deposit Dissolved load
Suspended load
Bed load
Deposit

10. Stream Load & Transport
Rolling
Suspension
Dissolution

11. Load is related to a stream's
Competence - maximum particle size
Capacity - maximum load

12. Factors that affect erosion and deposition
Velocity
Gradient (slope)
Channel shape
Channel size
Channel roughness
Discharge – amount of water flow per unit time, as discharge increases, load increases

13. Velocity

14. Velocity

15. Channel shape and roughness
Semicircular
Flow fast
Wide channel
Flow slow
Rough bottom
Flow slow

16. Upstream-Downstream Changes
Decrease
Gradient
Channel roughness
Increase
Velocity
Discharge
Channel size

17. “YOUNG” River Valleys
Rapids
Waterfalls
Narrow V-shaped valley
Steep gradient
Erosion is mostly downcutting
Little or no floodplain

18. A narrow V-shaped valley

19. The Yellowstone River in Wyoming

20. “MATURE” River Valleys
Stream is near base level
Less downward erosion
Stream energy is directed from side to side
Flood plain is evident
Some meandering (curves)

21. Continued erosion and deposition widens the valley

22. Wye River in England

23. “OLD” River Valleys Meanders well-developed Wide flood plain
Low gradient
Close to base level

24. The resulting wide stream valley is characterized by meandering on a well-developed floodplain

27. Flood plain development

28. Satellite view of the Missouri River flowing into the Mississippi River near St. Louis

29. Same satellite view during flooding in 1993

30. Erosion and Deposition Along a Meandering Stream

32. Deposition
Bar

33. Formation of an oxbow lake

36. Recent cutoff on the Arkansas River

37. Meander Loop on the Colorado River

38. Stream Deposition Floodplain deposits Alluvial fans Deltas
Natural levees: form parallel to the stream channel by successive floods over many years
Back swamps: marsh, yazoo tributaries
Alluvial fans
Develop where a high-gradient stream leaves a narrow valley
Slopes outward in a broad arc
Deltas
Forms when a stream enters an ocean or lake

42. Sacramento River levee---natural

43. Man-made levee on the Mississippi River in Gretna, LA

44. Formation of a Delta

45. Mississippi River delta---bird’s foot delta

46. Deltaic Lobe Switching

47. Nile River delta

48. Southern Alaska Delta