Runoff

Real World Example

Imagine trying to pour a large cup of water into an already full glass. Just like how the excess water spills over the edge of the glass because there's no more room to contain it, runoff occurs when water flows across the ground because the soil is too saturated to absorb any more. The ground acts like the full glass—once its capacity is reached, any additional water, such as rain, has nowhere to go but over the surface, just as the extra water spills out of the glass.