Surface run off
When soil eventually becomes saturated and cannot take anymore. Any extra rain flows overground
Infiltration
Some intercepted water is evaporated into the atmosphere. The rest strips from leaves to the soil and soaks in
Interception zone
when it rains very little Falls directly into rivers. As leaves and branches of plants trap a lot of the rain that falls.
Throughflow
Some seeps into the river through soil air spaces
Groundwaterflow
Keeps a river flowing even when theres no rain
Storm hydrograph
Shows how a river reacts to a rainfall event
Deforestation affect on hydrograph
Can change the hydrograph shape from B to more like a by reducing interception and infiltration
Afforestation effect on hydrograph
Has the opposite effect and is often used in Upland areas to reduce flooding (plant trees)
Land use change
replace fields or woodland with buildings and roads or pasture with crops. Both changes increase run-off so rain reaches a river quickly reducing lag time. The same is true of urbanisation.
