Interception

Interception is the storage of water above the ground surface, mostly in vegetation. Depending on the density of the vegetation cover a proportion of the rain is intercepted by the leaves and stems and temporarily stored on its surface.

Interception is important for the calculation of water balances in hydrology:

 
  • the net rainfall (water which reaches the ground ) is generally less than the total rainfall falling in top of the vegetation cover

  • almost one third of the total precipitation can be retained as interception (evaporating produces considerable interception loss).

 

Here the dependency of the interception capacity on the vegetation cover has been given.

Maximum values of interception capacity

 

 Main components of canopy interception for modeling are:

 
  • Throughfall

  • Stemflow

  • Canopy storage 

Main Interception Processes

 

Interception loss is usually calculated according to the threshold value method:

 

Where:

Ic(t)

 

Actual content of the interception storage mm

in(t)

 

Intensity of the precipitation on the soil mm/h

ETa(t)

 

Actual evapotranspiration rate from the interception storage mm/h

in(t)

 

Intensity of the rainfall that reaches soil mm/h

 

 


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Module
Hydrological modelling
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TUHH

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