How does a river change from source to mouth_ - Plantsbrook by pptfiles

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									 How does a river change from source
             to mouth?
• Long profile
                  Write a definition
• Cross profile       for each


• Upper course

• Middle course

• Lower course
How does a river change from source
            to mouth?
              Lower course



Answer: The section near the mouth. Mainly
deposition. Wide and deep. Landforms: levees
               and floodplains
 How does a river change from source
             to mouth?
                  Cross profile



Answer: The cross section, a view across the river
 How does a river change from source
             to mouth?
                Middle course



Answer: The middle section. Lateral erosion and
   deposition. Wider and deeper. Landforms:
          meanders and ox bow lakes
 How does a river change from source
             to mouth?
                  Long profile



Answer: The side view of the river from the upper
               to the lower course
 How does a river change from source
             to mouth?
                 Upper course



Answer: The section near the source of the river.
 Narrow and shallow. Vertical erosion. Abrasion
 and hydraulic action. Landforms: waterfalls and
                     gorges
 How does a river change from source
             to mouth?
• Long profile – the side view of the river along its
  course, from source to mouth
• Cross profile – the cross section through a river;
  cutting across the river
• Upper course – section near the source of the river.
  Narrow and shallow. Vertical erosion. Abrasion and
  hydraulic action. Landforms: waterfalls and gorges
• Middle course – the middle section. Lateral erosion
  and deposition. Wider and deeper. Landforms:
  meanders and ox bow lakes
• Lower course – section near the mouth. Mainly
  deposition. Wide and deep. Landforms: levees and
  floodplains
  Identify these landforms.....how are
              they formed?
A. Waterfall                      B. Meander
1. The resistant rock             1. The eroded material is
    collapses, causing abrasion       deposited creating a slip
    into the plunge pool              off slope
2. A river meets a band of        2. The slower current on the
    hard rock (resistant)             inside is due to the
3. The waterfall retreats             shallow water (more
4. The underlying soft rock is        friction)
    eroded                        3. The current is faster on the
5. The resistant rock is              outside of the bend due to
    undercut by abrasion              deeper (less friction)
                                  4. Erosion creates a river cliff
Identify this landform.....how is it
              formed?
                 1. The resistant rock collapses,
                      causing abrasion into the
                              plunge pool
                    2. A river meets a band of
                         hard rock (resistant)
                     3. The waterfall retreats
                  4. The underlying soft rock is
                                eroded
                      5. The resistant rock is
                         undercut by abrasion
Identify this landform.....how is it
              formed?
                    2. A river meets a band of
                         hard rock (resistant)
                  4. The underlying soft rock is
                               eroded
                      5. The resistant rock is
                        undercut by abrasion
                 1. The resistant rock collapses,
                      causing abrasion into the
                             plunge pool
                     3. The waterfall retreats
Identify this landform.....how is it
              formed?
                     1. The eroded material is
                      deposited creating a slip off
                                  slope
                  2. The current is faster on the
                      outside of the bend due to
                      deeper water (less friction)
                  3. Erosion creates a river cliff
                   4. The slower current on the
                      inside is due to the shallow
                         water (more friction)
                 5. The meander is a bend in the
                                  river
Identify this landform.....how is it
              formed?
                 5. The meander is a bend in the
                                  river
                  2. The current is faster on the
                      outside of the bend due to
                      deeper water (less friction)
                  3. Erosion creates a river cliff
                   4. The slower current on the
                      inside is due to the shallow
                         water (more friction)
                     1. The eroded material is
                      deposited creating a slip off
                                  slope
Identify this landform.....how is it
              formed?
                    1. Deposition cuts off the
                               meander
                 2. The river breaks through the
                      neck, usually during a flood
                  3. Erosion causes the outside
                        bends to move closer
                   4. The meander migrates as
                       erosion happens on the
                      outside and deposition on
                        the inside of the bend
                    5. A small area of land use
                     between the bends remains,
                            called the neck
Identify this landform.....how is it
              formed?
                    4. The meander migrates as
                         erosion happens on the
                       outside and deposition on
                          the inside of the bend
                   3. Erosion causes the outside
                          bends to move closer
                     5. A small area of land use
                      between the bends remains,
                             called the neck
                  2. The river breaks through the
                      neck, usually during a flood
                     1. Deposition cuts off the
                                 meander
Identify this landform.....how is it
              formed?
                   1. The heaviest material is
                      deposited closest to the
                                 river
                   2. A natural embankment
                       either side of the river
                  3. Deposited material builds
                        up creating the levee
                  4. During the flood, eroded
                     material is deposited over
                           the floodplain
Identify this landform.....how is it
              formed?
                   2. A natural embankment
                       either side of the river
                  4. During the flood, eroded
                     material is deposited over
                           the floodplain
                   1. The heaviest material is
                      deposited closest to the
                                 river
                  2. Deposited material builds
                        up creating the levee
Identify this landform.....how is it
              formed?
                 1. Deposition on the meander
                        slip off slope builds up
                     material on the floodplain
                  2. The wide, flat valley floor
                        either side of the river
                  3. Meanders migrate across
                       the floodplain making it
                                  wider
                 4. The river floods, the water
                     slows and deposits eroded
                                 material
Identify this landform.....how is it
              formed?
                  2. The wide, flat valley floor
                        either side of the river
                 4. The river floods, the water
                     slows and deposits eroded
                                 material
                  3. Meanders migrate across
                       the floodplain making it
                                  wider
                 1. Deposition on the meander
                        slip off slope builds up
                     material on the floodplain
A




    Spot the difference;
      lag time, peak
         discharge
B
 Hydrograph-what is it? Why are they
         different shapes?
Key words          Why are hydrographs different?
• Peak rainfall    • Urbanisation

                   • Rock type
• Peak discharge
                   • Gradient of the slope

• Lag time         • Deforestation
 Hydrograph-what is it? Why are they
         different shapes?
• Peak rainfall – the maximum amount of rainfall
  during the rainstorm

• Peak discharge – the maximum amount of discharge;
  the maximum amount of water in the river

• Lag time – the time delay between the peak rainfall
  and the peak discharge
  Hydrograph-Why are they different
             shapes?
• Urbanisation
                          Which are human
• Rock type               factors and which are
                          natural (physical)?
• Gradient of the slope
                          How does each factor
                          influence the
• Deforestation           hydrograph?
      Hydrograph-Why are they different
                 shapes?
• Urbanisation – building of towns. Steep rising limb,
  short lag time. Tarmac makes the surface impermeable.
  Increase surface run off = increase the water that flows
  into the river.
• Rock type – impermeable rock surface e.g. Granite (see
  above). Permeable surface allows the absorption of
  water and slows surface rune off.
• Gradient of the slope – steep slope increases surface
  run off = steep rising limb, short lag time.
• Deforestation – cutting down of trees. Short lag time.
  Trees intercept rain = long lag time.
 What is the demand for water in UK?
• Water surplus

• Water deficit

								
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