rivers

• Parts of a river

  • drainage basin
  • tributary
  • confluence
  • meander
  • OX-bow lake
  • flood plain
  • watershed
  • estuary
  • delta
  • mouth
  • source
  • route
• Route


  The route a river takes to the sea. Also known as Course.
• Source


  Starting point of the river
• Tributary


  Smaller river that joins the main river
• Confluence


  Where two rivers join together
• Meander


  Bend in the river
• Ox-bow lake


  Horse shoe shaped lake
• Flood plain


  Area of river where flooding happens
• Estuary


  Part of the river that becomes tidal
• Delta


  Triangular shape filled with sediment
• Mouth


  Where the river joins the sea
• Watershed


  Higher ground that separates two drainage basins
• Drainage basin


  Area drained by the river
• Stages of river development


  • youthful - upper stage
  • mature - middle stage
  • old - lower stage
• River processes


  • Erosion: The river wears the landscape away
  • Transportation: the river carries the materials that it has eroded
  • Deposition: the river drops the material it was carrying, to a new location
• Hydraulic action


  • The force of moving water breaks off material from the banks and bed of the river
• Abrasion


  • The material carried along by the river hits its bank and bed, wearing them away
• Attrition


  • The material is worn-down, smooth and rounded as the stones bounce off each other
• Solution


  • Acids in the water dissolve some rocks such as Limestone
• Processes of river transportation


  • Rolling (traction): The larger stones are rolled along the bed of the river
  • Bouncing: The smaller pebbles are bounced along the bed of the river
  • Suspension: Light materials such as sand and silt float along the river
  • Solution: Other materials such as sand and rock dissolve in the water and are carried along by the river
• River Deposition


  Shapes land by leaving sediment in new places
• Causes of Deposition


  • Reduction in the river's speed
  • Increase in load size
  • Reduction in river's volume
  • When the gradient levels off
• V shaped Valley

  • Found in the upper / youthful stage
  • Formed by erosion
  • Steep-sided "V" shape
• V shaped Valley

  • Upper course of River Liffey
• Interlocking Spurs


  • Found in the upper/youthful stage
  • Formed by erosion
  • Found on higher ground that juts out either side of V-shaped valley
• Interlocking Spurs


  • Upper course of river Barrow
• Waterfalls


  • Found in upper / youthful stage
  • Feature of erosion
  • Vertical drop in the course of the river
  • Processes of erosion: Hydraulic action, Abrasion, Attrition, Solution
• Waterfalls


  • Powerscourt, Co Wicklow
• Waterfall formation


  1. River flows over an area of hard rock

  2. Soft rock eroded more quickly, creating a vertical drop

  3. River falls over the vertical drop as a waterfall

  4. Waterfall increases in size, material the river carries creates a deep plunge pool through hydraulic action and abrasion

  5. Water splashes against the back wall, undercutting the waterfall and creating an overhang

  6. Pressure and gravity cause the overhang to collapse, waterfall retreats upstream

  7. Gorge forms at the side of the waterfall
• Waterfalls


  • Torc Waterfall near Killarney, Co. Kerry
• Meander


  A curve or bend in a river
• Meander


  • Found in mature stage
  • Feature of erosion and deposition
• Meander


  • Middle course of R. May
• Ox-bow lake


  • Horse-shoe shaped, formed from a meander
  • Found in mature stage
  • Feature of erosion
• Ox-bow lake


  • Middle course of R. May
• Levees


  • Build up of sediment on the sides of the river bank
  • Feature of deposition
• Levees


  • Lower course of River May
• Formation of Levees


  1. River carries a large load of sediment (alluvium)

  2. During a flood, the river spreads out and deposits the sediment

  3. Over time, a thick layer of alluvium builds up on the river's floodplain
• Alluvium is fertile and generally good for farming
• Levees provide a natural defence against flooding