River processes include abrasion/corrosion, attrition, hydraulic action, and corrosion/solution. Abrasion occurs as rock fragments carried in the riverbed wear away the riverbed and banks. Attrition involves the smoothing of rocks through pebbles and rocks colliding. Hydraulic action is when moving water is forced against riverbanks, causing them to collapse. Corrosion/solution uses the chemical reaction of slightly acidic water dissolving rocks like limestone. Other factors affecting erosion rates include gradient, rock type, bedload, and human factors.

1. River Processes

2. But What Do YOU Know?

3. What processes occur in a river?

4. Abrasion/Corasion Attrition Hydraulic Action Corrosion/Solution

5. Example of All Types of Erosion Steep Cliff Centrifugal Force River direction! Eroding Cliff Slip off slope. Deposition Occurs

6. Abrasion/Corrasion Fragments of rock carried by riverbed Wears away riverbed and banks Can carry tons of material Responsible for deepening valleys

7. Attrition Pebbles and rocks colliding Reduces their size Smoothens rock surface

8. Hydraulic Action Moving water forced against riverbanks Causes them to collapse and wash away

9. Diagram of Hydraulic Action

10. Corrosion/Solution Chemical reaction occurs Slightly acidic water dissolves calcium Breaks down rocks such a limestone

11. Other Factors Affecting The Rates of Erosion Include: Gradient Rock Type Bedload Human Factors

12. Plenary, What Have You Remembered?

13. What river process is where moving water is forced against riverbanks?

14. A. Hydraulic Action

15. Attrition is ........ and …….. colliding together

16. A. Pebbles and Rocks

17. What other factors effect erosion? A) Gradient, River speed, Bedload and Human Factors B) Gradient, Rock Type, Bedload and Human Factors C) Yoghurt, Rock Types, Nick’s earring and Jack’s iPhone D) Location, Rock Type, Bedload and Human Factors

18. B) Gradient, Rock Type, Bedload and Human Factors

19. In the process solution/corrosion, is the water acid or alkaline?

20. Acid

21. Thank You For Watching! And Enjoy The Painting Jack, Nick & Greg (FEHS Geog Students 2009-11)