A new bucket model for predicting water content in the surface soil layer

Discharge of water from the surface soil layer, which has non-uniform thickness and composed by various kinds of soil in horizontal plane, is examined by numerical experiments. The discharge takes place even in light rainy days . This feature does not occour in a case of uniform thickness of the soil layer. It is foud that an increase of soil water content after a rainfall is expressed by a hyperbolic curve as functions of the amount of precipitation, initial soil water content and the field capacity of the soil.