Storm hydrographs

• Storm hydrographs

  A) Small

  B) Large

  C) Bare

  D) Forest

  E) Steep

  F) Gentle

  G) Impermeable

  H) Permeable

  
• Main features of a hydrograph:

  • Once the rainfall starts, the discharge begins to rise - rising limb
  • Peak discharge is reached some time after the peak rainfall because the water takes time to move over and through the ground to reach the river.
  • The time interval between peak rainfall and peak discharge is known as lag time.
  • Once the input of rainwater into the river starts to decrease, so does the discharge; this is shown by the falling or recessional limb
  • Eventually the river's discharge returns to its normal level, or base flow.