Infiltration refers to which process?

• A. The movement of water from the soil to the atmosphere through evaporation
• B. The movement of water through the ground surface into the soil and downwards
• C. Water flowing on the surface as runoff
• D. Water seeping up from groundwater to surface as springs

Answer: (B)

Infiltration is the process by which water moves from the surface into the soil and then downward through the soil layers. When rain or irrigation wets the ground, some of the water soaks into the surface and percolates down through the pore spaces, driven by gravity and soil properties. This downward movement helps recharge groundwater and moistens the soil for plant roots. It’s different from evaporation, which is water turning into vapor and rising into the air; from runoff, which is water flowing over the land surface without soaking in; and from groundwater upwelling or springs, which is water moving upward from the groundwater to the surface. The rate of infiltration depends on soil texture, structure, and moisture; more permeable soils let water enter more quickly.