Does Clay Have High Permeability?

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. Gravel has the highest permeability.

Is clay low or high permeability?

Clay soils are known to have low permeability, which results in low infiltration rates and poor drainage. As more water fills the pore space, the air is pushed out. When all pore spaces in the soil are filled with water, the soil becomes saturated.

Why does clay not have high permeability?

Surprisingly, clay can have high porosity too because clay has a greater surface area than sand, therefore, more water can remain in the soil. However, clay has bad permeability. ... Since the soil/rock type has high porosity and permeability, water may move downward from gravity through the rock layer into lower layers.