WHAT CAN YOU REMEMBER?

1. WHAT CAN YOU REMEMBER? 2) _________ 3) _________ 4) _________ 1) ________ 5) __________ 6) ________ ocean land

2. WHAT CAN YOU REMEMBER? condensation precipitation transpiration evaporation surface runoff ground water ocean land

3. PHYSICAL LANDSCAPES INTRODUCING RIVERS

4. WHAT ARE WE GOING TO LEARN? • What is a drainage basin? • Why is a drainage basin like a kitchen sink? • What are the four processes of erosion in rivers? • What are the four processes of transportation in rivers?

5. Dyfi DRAINAGE BASIN THE DRAINAGE BASIN A drainage basin is an area of land that is drained by a river and its tributaries.

6. THE DRAINAGE BASIN The higher land that forms the edge, or boundary, of a drainage basin is called the watershed. Nature’s ‘kitchen sink’ WATERSHED

7. THE DRAINAGE BASIN All the rain that falls within a drainage basin flows into a single river channel that flows to the sea (or lake). Drainage basins act like nature’s kitchen sinks.

9. River Basin Features • Watershed the area of high land forming the edge of a river basin. • Source where a river begins. • Mouth where a river meets the sea. • Confluence the point at which two rivers meet. • Tributary a small river or stream that joins a larger river. • Channel this is where the river flows. • Drainage Basin this is the area of land drained by a river and its tributaries.

10. DRAINAGE BASIN TERMS SOURCE TRIBUTARY CONFLUENCE CHANNEL MOUTH

11. PHYSICAL LANDSCAPES THE RIVER COURSE

12. THE RIVER COURSE UPPER COURSE MIDDLE COURSE LOWER COURSE

13. RIVER PROCESSES Rivers play a big role in shaping our landscape. They are able to do this because they have energy. This means that they can do work. The work they do is erosion and transportation. When they run out of energy they have to stop doing work, so they drop what they are carrying. This is called deposition.

14. EROSION PROCESSES Erosion is the wearing away of the river bed, river There are four processes of river erosion: • attrition • corrasion • corrosion • hydraulic action

15. TRANSPORTATION PROCESSES • There are four processes of transportation: • traction • saltation • suspension • solution

16. TRANSPORTATION PROCESSES Solution Suspension Traction Saltation

17. RIVER EROSION

18. THE SOURCE • The source is the start or beginning of a river. • The source of a river is usually found in the hills or mountains.

19. SPRINGS rain Water can sink through gaps in the rocks Underground water emerges where the rock type changes Permeable rock ie Limestone Rocks are saturated Impermeable rock ie Clay Spring

20. THE RIVER COURSE UPPER COURSE MIDDLE COURSE LOWER COURSE

21. UPPER COURSE CHARACTERISTICS steep valley sides steep channel gradient narrow, shallow channel narrow valley floor

22. Upper Course Characteristics large, angular stones and boulders

23. UPPER COURSE CHARACTERISTICS turbulent river flow at a section of rapids

24. Upper Course Landforms a typical V-shaped valley

25. Key Features: • V-shaped valley A steep sided and narrow valley that is formed due to vertical erosion. The load of the river cuts downwards and deepens the bed of the river.

26. Upper Course Landforms a typical V-shaped valley

27. Upper Course Landforms interlocking spurs interlocking spurs

28. Upper Course Landforms interlocking spurs interlocking spurs

29. Angel Falls, Venezuela

30. Hopetoun Falls, Australia

31. Victoria Falls, Zambia/Zimbabwe

32. Jog Falls, India

33. Niagara Falls, Canada/USA

38. WATERFALL RETREATS . . OVERHANG PLUNGE POOL UNDERCUTTING OF SOFT ROCK UPSTREAM . .

39. Upper Course Landforms interlocking spurs interlocking spurs

40. Rapids A series of gentle breaks in the slope of a river bed due to different types of rock.

41. Hydro-electric power

42. Upper Middle Lower Course Course Course River Model

43. S3 Rivers: The Middle Course

44. At the middle stage of the river the valley sides become less steep • The river is now wider and deeper • It does not flow at the same speed throughout its middle course, some parts are slower, some are faster

45. Meander ( = bend in a river’s channel)

46. What do you notice about thebank of the river channel on the outside of the bend?

47. Which is the fastest side of a river?

49. Why do rivers meander (bend)? • Copy the diagram above and put the following labels in the correct place: • Deposition Fast flow of river Shallow water • River Cliff Lateral Erosion Slow flow of river Deeper water River beach (Slip-off slope) • 2. Describe why one side of the river bend is different from the other.