Rivers

• What are the 4 types of erosion?

  • Hydraulic action
  • Abrasion
  • Attrition
  • Solution
• What is Hydraulic action?

  Where the power of water smashes against river banks. Air becomes trapped in the cracks of the river bank and bed and causes the rock to break apart.
• What is abrasion?


  When pebbles grind along the river bank wearing it away like a sandpaper affect.
• What is attrition? 


  When rocks that the river is carrying knock against each other, they break apart and become smaller and rounded.
• What is solution erosion?

  When the water dissolves certain types of rocks.
• What are the 4 types of transportation?

  • Traction
  • Saltation
  • Suspension
  • solution
• What is traction?


  Where large, heavy pebbles are rolled along the river bed. Most commen near the source.
• What is Saltation?


  Pebbles are bounced along the river bed, mostly common near the source.
• What is Suspension?


  Lighter sediment is carried within the water, most commonly near the mouth of the river.
• What is solution transportation?

  The transport of dissolved chemicals. Varies along the river.
• What is deposition? 


  When the river loses energy, it drops any material that it has been carrying.
• What are 3 factors leading to deposition?

  • Shallow water
  • At the end of a rivers journey
  • When the volume of water in the river decreases
• What is a drainage basin?


  The area of land around the river that is drained by the river.
• What are the 6 types of drainage basins?

  • Watershed
  • Source
  • Mouth
  • Confluence
  • Tributary
  • Channel
• What is a Watershed?

  The area of high land forming the edge of a river
• What is the source of a river?

  Where a river begins
• What is the mouth of a river?


  Where the river meets the sea
• What is a confluence?

  The point at which 2 rivers meet
• What is a tributary?

  A small river or stream that joins a larger river
• What is the channel of the river?

  This is where the river flows
• What is the upper course of a river?

  Where the river starts, often an upland area. The rivers load (particles of rock carried by the river) is large in the upper course, it hasn't been broken down by erosion yet.
• What is the lower course of a river?

  The land is a lot flatter. The rivers load is fine sediment, as it has been broken down by erosion.
• What does a cross profile show?

  A cross profile shows a cross section of a rivers channel and valley at a certain point along the rivers course.
• When is a waterfall formed?

  When there are horizonal bands of hard rock and soft rock.
• How do waterfalls form?

  1. The soft rock is eroded quicker than the hard rock and this creates a step.
  2. As erosion continues, the hard rock is undercut forming an overhang
  3. Abrasion and hydraulic action erode to create a plunge pool
  4. Over time this gets bigger, increasing the size of the overhang until the hard rock is no longer supported and it collapses
  5. This continues until the waterfall retreats upstream