What causes water to move through pores in soil and rocks?

The movement of water through pores in soil and rocks is primarily influenced by gravity. When water infiltrates the ground, gravity pulls it downwards through the soil and rock layers. This process occurs as water percolates, filling the available spaces and voids between soil particles and rock. The ability of water to move downward through these materials is essential for groundwater recharge, which supports various ecosystems and drinking water supplies.

While gravity plays a critical role, other processes can influence how water behaves in the soil and rock matrix. For instance, capillary action—though it is important for water movement in smaller spaces—typically relates to the lateral movement and retention of water in soils, especially in finer-textured materials. Filtration refers to the purification process rather than the movement of water itself. Evaporation pertains to the conversion of liquid water into vapor, which does not directly explain how water moves through soil and rocks. Thus, gravity is the primary driving force for the downward movement of water through soil and rock pores.