Rivers Mind-Map

Rivers Mind-Map

Features
1. Source = Beginning of a river
2. Course of River = Route taken towards the sea
3. Tributary = Smaller river/stream that joins a larger river
4. Confluence = Where a tributary joins a river
5. Mouth = Where a river enters the sea
6. Estuary = Part of a river mouth that's tidal
7. River Basin = Area of land drained by a river
8. Watershed = High ground separating river basins
9. Erosion (n) = Gradual wearing away of land
3 Stages of a River
1. Upper/Youthful Stage
  1. Valley has narrow floor and steep sides
  2. Small amount of water but very fast
  3. Most energy used to erode
  4. Features: V-shaped valley, waterfalls, interlocking spurs, potholes
    1. V-Shaped Valley
      1. Get name from shape
      2. Landscape eroded in shape of a V
      3. Vertical Erosion occurs. River cuts into river bed, making it deeper. Creates a narrow, deep valley
      4. Mechanical weathering & mass movement
      5. e.g. River Liffey
    2. Interlocking Spurs
      1. River meets areas of hard rock
        Cannot erode these so instead flows around them while eroding downstream
      2. Zigzag course
      3. e.g. River Moy
    3. Waterfalls
      1. Rivers flow over areas of hard & soft rock
        River erodes the soft rock but can't erode the hard rock
        Falling water erodes deeper into the bed, creating a Plunge Pool
      2. e.g. Iquazu Falls
        One of the widest waterfalls in the world (1.5 miles across)
        On the border between Argentina & Brazil
        13 million litres of water spill over per second
        Found towards the end of its river
2. Middle/Mature Stage
  1. Valley has wider floor and sides are more gently sloping
  2. River starts slowing & deposits some materials
  3. Features: Wide river valley, meanders, flood plains
    1. Meanders
      1. Bends/curves along the river
      2. Formed by erosion and deposition
        Erosion occurs on one side while deposition occurs on the other
      3. e.g. River Shannon
3. Lower/Old Stage
  1. Valley has flat floor and gentle sides
  2. Carrying lots of sand & silt
  3. Moving over flat land so moving slowly
  4. Lots of deposition
    1. Creates many features/landforms
      1. Features: Ox-bow lakes, levees, deltas
        Ox-Bow Lakes
        Horseshoe shaped lake found beside a river
        Formed when continued erosion and deposition create very pronounced meanders
        Eventually the river cuts through the neck of the meander
        Deposition then occurs which separates the ox-bow lake from the river
Erosion Processes
1. Hydraulic Action = Force of moving water wears away banks and bed of river
2. Abrasion = Small stones carried by river wear away at banks and bed of river
3. Attrition = Small stones wear down as they hit each other
4. Solution = Rocks and soil are dissolved by acid in water
Erosion Ability
1. Speed of river (steeper = faster)
2. Volume (more water = increased ability to carry material)
Transporting Material
1. All rivers carry material
  1. e.g. sand, stones
  2. River's Load = All material
  3. River Transportation = River moves its load
    1. Traction = Large stones rolled along river bed
    2. Saltation = Small stones bounced along river bed
    3. Suspension = Light material (sand, silt, etc.) is carried (floating) in river
    4. Solution = Dissolved materials are carried by river
River Deposition
1. Deposits materials when:
  1. River slows (flatter land)
  2. Volume decreases (e.g. drought)
  3. River reaches sea

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	Created by Ben Moroney over 4 years ago