rivers

• Main features in a drainage basin

  • Source (where the river starts)
  • Watershed (imaginary line separating river basins)
  • Tributary (where smaller rivers join the main one)
  • Confluence (where two or more rivers join)
  • River basin (area where rain feeds the river)
  • Main river channel
  • Mouth of the river (where the river enters another body of water)
• Processes operating in a drainage basin

  1. Precipitation

  2. Condensation

  3. Evaporation

  4. Evapotranspiration

  5. Runoff

  6. Interception

  7. Throughflow

  8. Groundwater flow

  9. Percolation

  10. Transpiration

  11. Infiltration

  12. Water table
• Changes from source to mouth of a river

  • Increasing depth and width
  • Rising volume and speed
  • Amplifying discharge
  • Becoming more rounded
  • Due to erosion, transportation and deposition
• Erosion, transportation and deposition processes

  • Erosion (wears away river bed and banks)
  • Transportation (rivers carry materials)
  • Deposition (river drops its material)
• Comparisons between upper, middle and lower course of a river

  • Upper course: very steep and sharp, v-shaped valleys, gorges and waterfalls
  • Middle course: much more gentle
  • Lower course: almost flat, meanders and oxbow lakes
  • Upper course: narrowest
  • Lower course: widest
  • Middle course: in between