Drifting Classroom

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Rivers
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Discussion Section

• Referring to your fieldwork results, what type of
  river erosion did you find in your field site?
• Answer Lateral Erosion - results in widening
  of the valley - removal of material from valley
  walls

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• Referring to your fieldwork results, what is the
  direction of river erosion in your field site?
  How does it affect the river channel? Explain
  with an annotated diagram?
• Answer There are sideway erosion .

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• What are the types of river transportation? How
  do you know that they are taking place in your
  site? (Please use fieldwork results to support
  your analysis)
• Answer Traction . It is because the bed load is
  more heavy which cannot be lifted above the bed.
  Lots of them are pebbles .
• Saltation . It is because larger particles are
  moved in a series of hops and bounces along the
  river bed .

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• What are the characteristics of lower course?
  With the help of fieldwork results, for example
  river width, depth, cross-section, the size of
  bed loads and the nature of stream bed, to prove
  that your site is identified as lower course.
• Answer

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• Compared the width and depth of the channel with
  that of the upper course , the channel of lower
  course accommodates much more water . In my site
  , the width is 7m long and the deepest depth is
  28cm .
• The channel bed is smoother than the upper course
  .
• Heavier and angular load has greater potential
  for erosion .
• A large amount of load , mostly fine and rounded
  .

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• What is the feature found at Point A? What other
  feature(s) would be there? Describe and explain
  their formations, illustrate your answer with
  annotated diagrams.
• Answer We can find waterfall in Point A. In the
  upper course, there are interlocking spurs,
  rapids and potholes.
• Formation of waterfall River falls vertically
  down and forms waterfalls.
• Formation of interlocking spurs They are formed
  when the river water is unable to remove the
  obstacles on its path.
• Formation of rapids The river water is unable to
  erode the layer of resistant rock crossing the
  channel the uneven surface causes turbulent
  currents there. The turbulent currents are called
  rapids.
• Formation of potholes The water drills hollows
  with the load it carries. The hollow are called
  potholes.

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• What is the height difference among Point A, C
  and E? When there is prolonged torrential rain,
  which point(s) will suffer from flooding? Why?
  Suggest sustainable measures to cope with
  flooding.
• Answer Point A 40 m,
• Point C 0 m,
• Point E 0 m.
• Point E will suffer from flooding .
• It is because Point E has more tributaries .
• Suggestion We can build spillways to cope with
  flooding . This helps prevent the discharge to
  rise above the bank full discharge .

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References

• http//ihouse.hkedcity.net/hm1203/hydrosphere/riv
  er-work.htm
• http//www.geography-site.co.uk/pages/revision/riv
  er.html
• http//facweb.bhc.edu/academics/science/harwoodr/G
  eog102/study/river2.htm