In sandy soil, the movement of water is?

• A. more horizontal than vertical
• B. only vertical
• C. only horizontal
• D. more vertical than horizontal

Answer: (D)

In this case, water movement through soil is governed by gravity and the soil’s ability to transmit water. Sandy soils have large pore spaces and very high permeability, so water can move quickly downward under gravity. The capillary rise in sands is relatively weak, which means water doesn’t pull upward or spread laterally as much as it does when the soil has finer particles. Because downward flow is driven strongly by gravity and the soil doesn’t hold water to push it sideways, the vertical component of water movement dominates. Therefore, you’d expect water to move more vertically than horizontally.