5.2B Physical factor affecting the drainage basin

• Physical factors affecting the drainage basin

  • Climate
  • Soils
  • Vegetation
  • Geology 
  • Relief
• How climate affects the drainage basin:

  • The climate of an area in which a drainage basin is located affects:
  • The type and amount of precipitation
  • Extent of evaporation
  • Amount and type of vegetation 
• How soil affects the drainage basin:

  • The structure and type of soil can have a significant impact on:
  • Infiltration and through flow - the pores and openings in the soil affect how much infiltration occurs and the rate of throughfllow
  • Where soil is impermeable, saturated, compacted or frozen there will be low infiltration rates and high surface run off
• How vegetation affects the drainage basin:

  • The amount and type of vegetation affects:
  • Interception, infiltration, drip flow and trunk and stem flow
  • The more vegetation the greater the amounts of those flows
  • Where there is less or no vegetation these are all reduced and surface run off increases
• How geology affects the drainage basin:

  • The type of rock below the surface affects:
  • Whether water is able to percolate and also affects the amount of groundwater flow
  • The geology also affects the type of soil which then impacts on the flows in the drainage basin
• How relief affects the drainage basin:

  • The steepness of slopes impacts on:
  • Surface run off - on flatter slopes the water is able to infiltrate more easily, reducing surface run off, on steeper slopes infiltration is reduced and surface run off is increased
  • Upland areas also experience more precipitation which affects the flows through the drainage basin