factors influence discharge of river / input precipitation

Question 1

rainfall type

Answer 1

• the amount and duration determines how saturated the ground is
• long period of rainfall = soil reaches field capacity
• therefore blocks infiltration and leads to high surface run off

Question 2

antecedent conditions

Answer 2

• several weeks of prolonged, heavy rainfall cause drainage basin to reach saturation capacity very quickly after a storm event
• can also lead to a rise in the level of water table
• further increasing the likelihood of a saturation capacity being exceeded

Question 3

vegetation cover

Answer 3

• amount of rainfall which reaches the drainage basin is influenced by vegetation cover
• drainage basin covered in dense vegetation will experience high rates of INTERCEPTION,
  ROOT UPTAKE, EVAPOTRANSPIRATION
• which reduces the amount of discharge within the basin
• tropical forests are thought to intercept up to 80% rainfall, whereas arable (suitable for cultivating crops) land intercepts less than 10% of rainfall

Question 4

rainfall density

Answer 4

heavy rainfall may exceed the infiltration capacity of soil
- lead to surface runoff and rapid increase of discharge

Question 5

geographic distribution

Answer 5

• the location of rainfall event and amount of the drainage basin which receive the precipitation
• e.g rain in forest areas are most likely to be held in store
  rain in mountainous areas most likely to flow quickly into rivers