1. EARTH SCIENCE Prentice Hall EARTH SCIENCE Tarbuck Lutgens 

2. 6 Chapter 6 Running Water and Groundwater

3. The Work of Streams Chapter 6.2

4. Erosion 6.2 The Work of Streams  Streams generally erode their channels, lifting loose particles by abrasion, grinding, and by dissolving soluble material.  The ________ the current, the more the erosion power  Sand and gravel polish rocks like ___________ grinds down wood

5. Sediment Transport 6.2 The Work of Streams 1.In solution (Dissolved Load) 2.In suspension (Suspended Load) 3.Scooting or rolling along the bottom (Bed Load)  Streams transport sediment in three ways

6. Sediment Transport 6.2 The Work of Streams 1.In solution (Dissolved Load) A.Dissolved materials in the water B.expressed as parts of dissolved material per million parts of water (parts per million, or ppm)  Streams transport sediment in three ways

7. Sediment Transport 6.2 The Work of Streams 2. In suspension (Suspended Load) A. Largest part of a streams load is carried this way, includes sand, silt and clay B. The capacity of a stream is the maximum load it can carry.  Streams transport sediment in three ways

8. Sediment Transport 6.2 The Work of Streams 3. Scooting or rolling along the bottom (Bed Load) A. Made up of sediment too large to be carried B. Suspended and dissolved loads are always moving  Streams transport sediment in three ways

9. Deposition 6.2 The Work of Streams  Deposition occurs as streamflow drops below the critical settling velocity of a certain particle size. The deposits are called alluvium.  Deltas are an accumulation of sediment formed where a stream enters a lake or ocean.

10. Deposition 6.2 The Work of Streams  A natural levee parallels a stream and helps to contain its waters, except during floodstage.

11. Deposition 6.2 The Work of Streams  What happens when a levee breaks?  Floods

12. Floods and Flood Control 6.2 The Work of Streams  A flood occurs when the discharge of a stream becomes so great that it exceeds the capacity of its channel and overflows its banks.  Measures to control flooding include: A. Artificial levees B. Flood control dams C. Placing limits on floodplain development.

13. Floods and Flood Control 6.2 The Work of Streams  Floodplain is the flat, low-lying portion of a stream valley subject to periodic flooding

14. Hurricane Floyd 1999 Flooding

17. Greenville, NC

18. Stream Valleys 6.2 The Work of Streams  Narrow Valleys A narrow V-shaped valley shows that the stream’s primary work has been downcutting toward base level. Features often include - rapids - waterfalls

19. The Yellowstone River Is an Example of a V-Shaped Valley

20. Stream Valleys 6.2 The Work of Streams  Wide Valleys Stream is near base level. - Downward erosion is less dominant. - Stream energy is directed from side to side. The floodplain is the flat, low-lying portion of a stream valley subject to periodic flooding.

21. Stream Valleys 6.2 The Work of Streams  Wide Valleys Features often include - meanders - cutoffs - oxbow lakes

22. Drainage Basins 6.2 The Work of Streams  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.

23. Drainage Basins