Which term describes the movement of infiltrated water down through soil layers?

Which term describes the movement of infiltrated water down through soil layers?

• A. Evaporation
• B. Through flow
• C. Percolation
• D. Runoff

Answer: (B)

When water has infiltrated the soil, it moves through the pore spaces in the soil layers as it travels downward. This subsurface movement is described as through flow. It happens as gravity pulls the water through the soil matrix, and it can feed deeper layers and recharge groundwater. This process is distinct from evaporation, which loses water to the air from the surface, and runoff, which is water that moves across the surface. While percolation is a related term often used for downward movement through soil and into deeper layers, the description given—water moving down through the soil layers itself—aligns with the idea of through flow.

When water has infiltrated the soil, it moves through the pore spaces in the soil layers as it travels downward. This subsurface movement is described as through flow. It happens as gravity pulls the water through the soil matrix, and it can feed deeper layers and recharge groundwater. This process is distinct from evaporation, which loses water to the air from the surface, and runoff, which is water that moves across the surface. While percolation is a related term often used for downward movement through soil and into deeper layers, the description given—water moving down through the soil layers itself—aligns with the idea of through flow.