Definition - What does Infiltration Capacity mean?
Infiltration capacity, or infiltration rate is the ability of how fast or how slow soil and rocks absorb rain. The rate by which soils and rocks can absorb fresh fallen rain or water from irrigation systems is related to the soil content, grain size and if there is any cover from vegetation.
WineFrog explains Infiltration Capacity
If a soil's infiltration rate is insufficient, due to a physical barrier, lack of soil aeration or if it is saturated, runoff occurs. This is correlated to the hydraulic conductivity of the soil near the surface. It can be measured with a special tool called an infiltrometer.
Both gravity and capillary action are the two forces which cause infiltration. The infiltration rate can be determined by the characteristics of a soil based on its transmission rate through the soil and its storage capacity.
For example, coarse, sandy soils have large spaces allowing water to infiltrate at a fast rate. Vegetation and biological life such as worms and valuable insects can also aid in creating more porous soils, but also protect it from runoff when there is excess water present. In contrast, soils which are poor in organic and biological life do not have high porosity and therefore, runoff is more frequent along with high erosion rates. This can be detrimental to plant life and soil life.