Rivers

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  • Rivers
    • Rivers system
      • Upper Course
        • Gradient= steep
        • Discharge = small
        • Depth=Shallow
        • Channel Shapes= narrow, steep sides
        • Velocity= Quiet fast
        • Valley Shape=  Steep sides
        • Features = waterfalls, interlocking spurs
      • Middle Course
        • Gradient= less steep
        • Discharge= large
        • Depth=deeper
        • Channel shape= Flat, floor, gently sloping sides
        • Velocity=fast
        • Valley shape = flat with steep sides
        • Features=meanders, floodplains
      • Lower course
        • gradient =shallow gradient
        • Discharge= very large
        • depth= deep
        • channel shape= flat floor, gently sloping sides
        • Velocity= very fast
        • Valley features= flat with gently sloping sides
        • Feature = meanders, floodplains, levees, ox-bow lakes
    • Weathering
      • Freeze-thaw
        • Water accumulates in a crack in the rock, freezes and expands
          • Rainwater enters the crack in a rock. If it freezes it expands and exerts pressure on the rocks and the rocks can eventually break into smaller pieces
      • Biological
        • tree roots can penetrates cracks in the rocks and split them apart
      • Chemical
        • Rainwater is slightly acidic and can dissolve some rock, especially limestone and chalk
    • Mass movement
      • soil creep
        • Partials of soil slowly moves down the sides of valley under the influence of gravity
      • Slumping
        • Valley sides are eroded by the river making the sides steeper and increasing the downward movement of materials. Heavy rainfall can trigger this movement

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