GEOLOGY

Detailed explanation-1: -Clay is the most porous sediment but is the least permeable. Clay usually acts as an aquitard, impeding the flow of water. Gravel and sand are both porous and permeable, making them good aquifer materials.

Detailed explanation-2: -Gravel is highly porous and permeable because each space between a piece of gravel is a pore that water can get into. Because the pores are large and close together, water can travel through it easily. By contrast, clay has smaller pores.

Detailed explanation-3: -Porosity and permeability are separate but related characteristics of soil and rocks. While porosity is the percent of open spaces or voids within a volume of soil or rock, permeability is the rate of water movement through interconnected pores within soil or rock.

Detailed explanation-4: -Usually the larger the consolidated (well sorted) grain size, the better the permeability (aquarium gravel). With this sediment size, there is plenty of connectedness of pore space, allowing the water to drain out of the soil sample quickly.