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Rivers

Rivers. Chapter 7. Rivers………. Start on high, Flow down low, Creating features As they flow!. River Terms. Three stages of a river. Three stages of a river. Youth Stage = Upper Course Mature Stage = Middle Course Old age Stage = Lower Course. The Work of Rivers. Processes of Erosion.

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Rivers

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  1. Rivers Chapter 7

  2. Rivers……… Start on high, Flow down low, Creating features As they flow!

  3. River Terms

  4. Three stages of a river

  5. Three stages of a river Youth Stage = Upper Course Mature Stage = Middle Course Old age Stage = Lower Course

  6. The Work of Rivers

  7. Processes of Erosion How a river erodes

  8. The Work of Rivers Processes of erosion: Hydraulic Action The force of the moving water causes erosion of the river bed and the banks of the river. The greater the speed and amount of water the greater the force.

  9. The Work of Rivers Processes of erosion: 2. Abrasion The rivers load is bounced and dragged along the river bed causing it to scrape and deepen the course of the river.

  10. The Work of Rivers Processes of erosion: 3. Attrition The rivers load is constantly colliding in the moving river water causing the load to break down into smaller pieces.

  11. The Work of Rivers Processes of erosion: 4. Cavitation As a river flows over the uneven river bed air bubbles travel up to the top of the river, pop and send ripples out towards the river banks. These ripples gently erode the rivers banks.

  12. The Work of Rivers Processes of erosion: 5. Solution Chemicals in the rivers water and rocks along the river course change the river chemically which reacts with and erodes various rocks along the way.

  13. Transport How a river moves its load

  14. Features

  15. Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found) E: Explain with at least one or two processes explained E: Three examples, one Irish D: Clear 1/2/3 diagram/s to show how the feature is formed.

  16. Three features we will study Youth Stage = Waterfalls Mature Stage = Meanders and Oxbow Lakes Old age Stage = Deltas

  17. Features of the Youth Stage • V – Shaped Valleys • Interlocking Spurs • Waterfalls

  18. Interlocking spurs A typical upper course V-Shaped valley with interlocking spurs, steep valley sides and active slope processes. The diagram below shows the formation of interlocking spurs.

  19. 1 2 3 4

  20. Feature of Erosion Name Waterfall Found Youth Stage Processes involved Hydraulic Action Abrasion

  21. Waterfalls f Waterfalls are features of erosion usually found in the upper course (youth stage) of a river. They are found in areas where a river is flowing over bands of hard and soft rock. The hard rock is slower to break down but the river can erode the soft rock much quicker. A band of hard rock lies on an area of soft rock. The river erodes the soft rock by the processes of hydraulic action (the force of the moving water) and abrasion (the scraping of the rivers load against the banks and bed). This causes a small notch to be formed into the soft rock which is eroded further into a drop over which the water falls. As the water falls over the drop there is a greater rate of hydraulic action and the rivers load also scrapes and deepens a hole in the bottom of the waterfall. This hole is called a Plunge Pool. The hard rock is slowly eroded and hangs over the edge called a Overhang. This is eventually worn down by the river and is carried away as the rivers load. e

  22. e Examples of waterfalls include: 1 2 3 Diagram of a waterfall being formed d

  23. Examples Angel Falls, Venezeula Victoria Falls, Zimbabwe Torc Waterfall, Killarney, Kerry

  24. 1A2

  25. 1A5

  26. foe/sor (e) px2 weu Aoh/sr srw Waterfall ucipp neisr pp@bow rfovd

  27. foe/sor= Feature of erosion….stage of river Weu= Waterfall erodes upstream (e) px2= Erosion, Process are hydrualic action and abrasion Aoh/srsrw= Areas of hard/soft rock, soft rock weaker Ucipp= Undercut collapses into plunge pool Waterfall Neisr= Notch eroded in soft rock pp@bow= Plunge pool at base of waterfall Rfovd= River falls over vertical drop

  28. Can you put the labels below into the correct place on he diagram?

  29. Feature of Erosion and Deposition Name Meanders and Ox Bow Lakes Found Mature and Old Age Stage Processes involved Erosion and Depositon

  30. Ox Bow lake on Mississippi

  31. Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found) E: Explain with at least one or two processes explained E: Three examples, one Irish D: Clear 1/2/3 diagram/s to show how the feature is formed.

  32. 1a2

  33. 1a5

  34. Describing a feature F.E.E.D F: Feature (Name, erosion or deposition, stage it is found) E: Explain with at least one or two processes explained E: Three examples, one Irish D: Clear 1/2/3 diagram/s to show how the feature is formed.

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