infiltration

Infiltration is the process by which water on the ground surface enters the soil. It's a crucial part of the hydrologic cycle, determining how much water becomes surface runoff versus how much soaks into the ground. The rate at which soil can absorb water is called infiltration capacity.123

When rain falls, some of it may be intercepted by vegetation or evaporate. If it reaches the ground, it can infiltrate the soil. The rate of infiltration depends on factors like rainfall intensity, the initial moisture of the soil, and the soil's hydraulic properties. If rainfall exceeds the soil's infiltration capacity, the excess water becomes surface runoff. Water that infiltrates the soil can move downward through the soil profile, a process also known as percolation, eventually reaching groundwater.1456