1. TRANSPORTATION & DEPOSITION in a Stream System

3. Transportation: The movement of the particles

4. Streams can move particles because the running water has kinetic energy. The energy with which the water flows is determined by three factors: 1) Velocity 1) Velocity - distance water travels in a given amount of time (think: quickness) 2) Stream Gradient 2) Stream Gradient - steepness or slope of the land that makes the streambed 3) Discharge 3) Discharge - volume of water that passes a certain point in a given time.

5. Factors affecting VELOCITY  The slope of the stream

6. Factors affecting VELOCITY  The contents and shape of the streambed

7. Factors affecting GRADIENT  The relief of the land that the stream flows downhill on.

8. Factors affecting DISCHARGE  How large the stream’s watershed is.

9. Factors affecting DISCHARGE  The amount of water flowing through the tributaries that feed the main stream.

10. PARTICLE vs. ENERGY The amount of particles a stream can carry and the size of the particles a stream can carry are both based on how much energy the flowing stream has at any given time.

11. All of the mass that is being transported by a stream is called the load. The stream’s load changes as the stream either gains or looses energy.

12. A stream’s kinetic energy directly impacts the following 2 stream characteristics:  Competence size  Competence – a measure that describes the maximum size particles a stream can carry.  Capacity amount  Capacity – total amount of sediment a stream can carry.

13. A stream’s competence can be measured by observing the sizes of the particles being transported in its load. Different size particles move in different types of transportations.

14. SOLUTION SOLUTION – smallest sizes, like clay particles, are dissolved in the stream’s water.

15. SUSPENTION SUSPENTION – Silt and small sands are floating and carried with the water.

16. SALTATION SALTATION - larger sizes (sand and greater) can be bounced along the streambed.

17. TRACTION TRACTION -the largest (boulder) sizes are rolled along during heavy stream flow events.

18. Deposition: The laying down of the particles

19. Differences in a stream’s energy cause the stream to not have the ability to carry sediments. This decreases the capacity and competence. When this happens, sediments are deposited, or laid down.

20.  Areas where sediments are deposited become common features found along a stream system.

21. Alluvial Fans – When streams come out of mountain valleys, they lose a great deal of velocity and deposit massive amounts of larger sediments.

22. Sand Bars - Occur where stream currents deposit large amounts of sand-sized sediment in isolated areas.

23. Braided Stream - A network of small channels separated by small temporary islands of sediment.

24. Deposits happen along floodplains after heavy water events. These sediments are removed materials from the stream channel

25. Levee – build up of sediment on the banks of a stream channel that occurs after flooding.

26. Delta - Area where sediments are deposited at the mouth of a river

27. Meanders: Meanders: Erosion and Deposition Working Together

28. MEANDERING STREAMS  Meandering streams wander side to side as they constantly seek out the lowest elevation.  This constant motion creates a series of S-shaped “loops”.  Stream velocity varies from one side to the other side of the “S”, resulting in erosion in some places and deposition of sediments in others.

29. Inside & Outside Banks Refer to a side of the curve of a meander Outside Bank   Inside Bank

32. Cut-bank Cut-bank - forms on outside of curve of meandering streams or rivers due to higher water velocity, which causes erosion on outside of curves. Point bars Point bars - form on inside of curves of meandering streams or rivers where velocity is less, causing sediments to be deposited.

34. Differences between Inside and Outside Banks of a Meander Curve: INSIDE CURVE OUTSIDE CURVE Velocity Water moves slower. Water moves faster. Action Deposition builds up Bank becomes eroded Features Area of deposition is called a point bar. Area of erosion is called a cut bank. Energy ? ?

35. The combination of erosion and deposition that occurs in meanders causes the formation of oxbow lakes and cutoffs.

37. Cutoff – where stream erodes through a meander, reconnecting it and leaving an oxbow lake.

38. Eventually, it takes too much energy to keep meandering, so rivers will cut off a bend, resulting in an oxbow lake.

39. erosion deposition Locate areas of erosion and deposition on the following slide of a stream system:

40. Alluvial Fan