1. Stream Development

2. Objective
1. Define deposition as the process by which Earth materials carried by wind, water, or ice settle out and are deposited.
2. Describe the agents of erosion: gravity, water (running water and waves), glaciers, and wind.
3. Explain that running water (rivers, streams, and runoff) is the major cause of erosion.

3. Objective
4. Identify the sources of fresh water on the Earth’s surface.
5. Describe the process of stream development and the associated landforms.
6. Design and construct experiments using stream tables to infer relationships between gradient, slope, speed, and extent of weathering and erosion.
7. Explain the types of deposition specific to streams and rivers (such as alluvial fans and deltas).

4. Enduring Understanding
Weathering, erosion, and deposition are interrelated processes that form a cycle of forces that wear down and build up the Earth’s surface.
Water is continuously passed through the hydrologic cycle.
Fresh water is necessary for survival and most human activities.

5. Stream Development
As a stream develops it changes shape, width, and size as well as the landscapes over which it flows.

6. Stream Development
Streams are responsible for the majority of the landforms we see today
Alluvial Fan

7. Stream Development
Precipitation supplies the water for the beginnings of stream development

8. Stream Development
Headwaters is the region where water first accumulates to supply a stream

9. Stream Development
Headwaters are commonly found high in the mountains

10. Stream Development
Stream channel is a narrow pathway carved into the sediment or rock by moving water

11. Stream Development
Stream bank is the ground bordering each side of the stream

12. Stream Development
Stream piracy occurs when one stream draws away water from another

13. Stream Valleys
As a stream actively erodes its path through the sediment or rock it develops a specific recognizable landform

14. Stream Valleys
V-Shaped channels are formed by streams and have steep sides that form at an angle

15. Stream Valleys
Gorges and canyons are very old V-shaped channels

16. Stream Valleys
The Grand Canyon formed by the Colorado River is one very recognizable V-shaped valley

17. Stream Valleys
Base level is lowest elevation a stream will cut its valley to and coincides with the level of the lake or larger stream it runs into

18. Stream Valleys
Sea level is the ultimate base level

19. Meandering Streams
As streams continue to cut and widen their channels the amount of water and sediment they can carry increases.

20. Meandering Streams
As the stream approaches base level the slope decreases and water builds up it begins to erode the sides of the channel.

21. Meandering Streams
Meander is the bend or curve in a stream channel

22. Meandering Streams
The water flowing in a stream moves at different speeds. It is fastest in the middle of a straight flowing stream because friction slows the sides and bottom.

23. Meandering Streams
When a stream begins to make a turn this changes and forms very interesting features

24. Meandering Streams
Water on the outside of the curve flows faster than the water on the inside of the curve

25. Meandering Streams
This water erodes away the outside bank and makes the meander even larger

26. Meandering Streams
Cut bank is the result of the greater erosion

27. Meandering Streams
The slower water on the inside of the curve causes deposition of the sediment

28. Meandering Streams
Point Bar is the resulting feature

29. Meandering Streams
Oxbow Lakes are meanders that become completely blocked off by deposition of sediment

30. Stream Deposition
As streams slow they lose their ability to carry sediment. This is most commonly the result in a decrease in gradient or slope of the landscape over which the stream flows

31. Stream Deposition
Alluvial fan is the sloping deposited sediment at the base of a steep slope and is most commonly found at the base of mountains in dry regions

32. Stream Deposition
Delta is the triangular deposit that forms when a stream enters a large body of water.

33. Stream Deposition
Deltas grow as stream deposition blocks the pathway of the moving water and smaller distributary streams branch out to form their own deposits

34. Stream Deposition
The Mississippi River delta began forming millions of years ago but it has deposited enough sediment in just the last 5,000 years to build the city of New Orleans on