The Theory for the Layered Darcy’s Law interface is based on Darcy’s Law which is described in Theory for the Darcy’s Law Interface. Therefore, this section focuses on the 2D approximation for layered materials.

The Darcy’s Law with continuity equation can be found in Section Theory for the Darcy’s Law Interface, Equation 4-2. The Darcy velocity can be written as:

where κ is the permeability of porous material, μ is the dynamic viscosity of fluid, ρ the fluid density, p is the fluid pressure, g is the gravitational constant, and D is the elevation.