Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.

What does it mean to have greater permeability?

Permeability defines how easily a fluid flows through a porous material. Materials with a high permeability allow easy flow, while materials with a low permeability resist flow.

Which soil type will have the highest permeability?

Sandy soils are known to have high permeability, which results in high infiltration rates and good drainage. Clay textured soils have small pore spaces that cause water to drain slowly through the soil. Clay soils are known to have low permeability, which results in low infiltration rates and poor drainage.