1. Surface Water Stream landscapes, erosion and deposition

2. The Water Cycle
Water constantly moves among the oceans, the atmosphere and on land. This unending circulation of Earth’s water supply is the water cycle.
Evaporation- liquid water to water vapor
Precipitation- water vapor to liquid water
Infiltration- water absorbed by land (soil, cracks in rocks)
Runoff- water flowing over land

4. Erosion Erosion is the transport of weathered material
Caused by water, wind or glaciers.

5. Gravity The root cause of all erosion
Materials falling downhill are called Mass Movements
Examples
Landslides
Avalanches
mud flow
rock fall

7. RUNNING WATER The most common agent of erosion on Earth’s surface
Streams or water flowing over the ground pick up and move material.
These particles weather rocks from abrasion

8. Stream Formation Run-off is the flow of water over the ground
Run-off results in the formation of streams
Streams that flow into other streams are called tributaries

9. Stream velocity Velocity is fastest at the top center
Slowest near the stream bed
Velocity is fastest at the outside of a turn
Results in rapid erosion and carves out the deepest part of stream

10. Meanders
As a stream flows across the flood plain, it meanders, or curves back and forth
This is caused by erosion over time.

11. Point bar- deposition occurs on the inside of the curve where flow slows down
Cut bank- erosion occurs on the outside of the curve where flow is fastest

12. Oxbow lakes
When a meander gets extreme it will erode back on itself and form an oxbow lake

15. Carrying Capacity Particle size
How much material a stream can carry relates to the velocity (speed) of water.
Particle size
Higher velocity = larger sediment
can be carried down stream
As the stream slows, it deposits larger particles.

16. Page 6 ESRT

17. Stream Velocity…(see page 6 of ESRT)
As stream velocity increases, the volume and size of sediments being carried increases.
Volume and particle size
Velocity of stream

18. Conversely, as stream velocity decreases, the settling rate increases.
Incoming stream with sediments
Coarse gravel
Finer sand
Finer silt
Finest clay

19. STOP!

20. River Deposition
Deposition is the laying down of weathered and eroded sediments (bits and pieces of larger rock masses).
Occurs when velocity of the erosional agent (water, wind, glaciers) decreases
Most deposition occurs in bodies of water.

21. River deposits
Deltas - triangular fan shaped deposits that develop as a stream or river flows into a larger body of water
Alluvial fans – same kind of deposits but on land

22. GLACIAL EROSION
As a large mass of ice (at least 100 ft thick) moves downhill, from gravity, it picks up rock material.
The material grinds against and scratches the underlying rock.
This is called abrasion.
There are two types of glaciers, valley glaciers and ice sheets

23. This is a valley glacier, which flows
like a stream, down hill.

24. V U Streams cut V-shaped valleys due to downward erosion
Glaciers cut U-shaped valleys due to sideways erosion

26. YOSEMITE VALLEY, California

27. Deposition by Glaciers
As a glacier retreats (ice melts), it drops all the material in and on it.
Note: the glacier never moves backwards, the front just melts back.
A variety of deposits are left behind, some are sorted and some are unsorted.

29. GLACIER
animation