Flow of water in saturated soil is described by

Darcy’s law is an equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on the results of experiments on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth science.
Hagen- Poiseuille has given a physical law that gives the pressure law that gives the pressure drop in an incompressible fluid.
Thus, the flow of water in saturated soil is described by both Poiseuille and Darcy.