Rivers

• Run-off or surface drainage


  Water in a river that comes from rain and springs, flowing on the surface
• Source of a river

  Where the river begins
• Mouth of a river


  Where the river ends, meeting the sea
• Catchment area or drainage basin


  An area drained by a major river and its tributaries
• Watershed


  A line of high land that separates the headwaters of different river drainage systems
• Tributary


  A stream that flows into a larger river
• Confluence


  The place where a tributary meets the main river
• Distributary


  A channel or river that splits from the main river and enters the sea by a separate mouth
• Perennial stream


  A stream that flows all year round
• Seasonal stream


  A stream that flows in the wet season
• Valley


  A depression that slopes towards the sea
• River bed


  The floor of the river
• Consequent stream


  The main stream
• Subsequent streams


  Tributaries of the main stream
• Drainage basin


  The area drained by a major river and its tributaries, enclosed by a watershed
• Drainage patterns of rivers

  • Dendritic pattern
  • Radial pattern
  • Trellis pattern
• River erosion


  1. Corrasion/abrasion

  2. Hydraulic action

  3. Attrition

  4. Solution
• Bed load


  Heavy materials transported along the river bed
• Saltation


  Sand and other light materials hopping along the river bed
• Traction


  Gravel and pebbles rolling, sliding or being dragged along the river bed
• Stream load


  Lighter materials transported in suspension or solution in the river water
• Stages of a river

  • Upper/youthful course
  • Middle/mature course
  • Lower/old age course
• Upper/youthful course


  • Steep valley sides, narrow V-shaped cross-section
  • Erosional work
• Middle/mature course


  • Lateral erosion, widening valley
  • Meandering river
• Erosion on concave bank


  Deposition on convex bank
• A river is always working, performing erosion, transportation and deposition