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Rivers (Rivers shape our land (Features of a river (Stages of a river…

- - - - Dropping material that was transported
      - The river Deposits things when:
        
        It loses speed
        
        Its volume decreases
        
        It flows into a lake or sea
    - - Removing material that it has eroded
      - Boulders are rolled along the bed of the river
      - Pebbles bounce along the bed of the river
      - Silt and clay are carried along the water
      - Dissolved materials are carried in solution
    - - Abrasion
        
        Material hits the banks as its moving along and wearing the river bed away
      - Hydraulic action
        
        Force of moving water breaks off material from the river bed
      - Attrition
        
        The material is smoothed by other material hitting off each other
      - Solution
      - wearing material away from the surface
  - - - Where a river enters the sea
    - - Part of river mouth which is tidal
    - - Where 2 rivers meet
    - - Area of land drained by a river and its tributaries
    - - Small river or stream that joins a bigger one
    - - Boundary between 2 drainage basins, usually between hills or mountains
    - - Route taken by a river as it flows to the sea
    - - Beginning of a river
    - - Youthful stage
        
        Small
        
        Steep Gradient
        
        Narrow bed
      - Mature stage
        
        Bigger
        
        Gentler gradient
        
        Wider bed
      - Old stage
        
        Much bigger
        
        Almost a flat gradient
        
        wide flat floor
- - - - Narrow floor
      - Steep sides
      - Weathering breaks up rock and soil on the valley sides
      - Vertical erosion occurs because the force of the water and stones cut down into the river bed
      - E.g. youthful stages of the River Liffey
    - - Occurs when rivers meet hard and resistant rock and is unable to erode through them
      - It winds and bends to try and avoid them
      - The river is still trying to erode downwards
      - Zigzag course
      - E.g. Early stages of the rivers Moy
    - - Waterfalls are formed when a layer of hard rock is on top of a band of softer rock
      - Water carrying loads helps to erode a deep hole called a plunge pool
      - The falling water cuts under the waterfall to form an overhang of hard rock, which eventually collapses
      - The waterfall retreats upstream to form a gorge
      - E.g. Aasleagh Falls
  - - - The river swings side to side removing interlocking spurs
      - Valley floor widened by lateral erosion
      - Valley sides are less steep
      - E.g. Mature stages of the river Boyne
    - - The river deposits some of its load there
      - The meander becomes more prominent
      - E.g. Found along the course of the river Shanon
      - Outer bank is deeper, flows faster so more power to erode the bank
    - - Overflow its banks after a period of rainfall
      - As it spreads over the land, it slows down and loose its alluvium (the material the river was carrying)
      - A thick layer of alluvium builds up to form a flood plain
      - E.g. They have developed along the sides of the river Liffey