It states that for laminar flow, the rate of flow or discharge per unit time is directly proportional to hydraulic gradient.
q= KiA or V= / = Ki
Where q= discharge per unit time. , A= total cross-sectional area of soil mass, perpendicular to the direction of flow, i= hydraulic gradient = h/L, K = Darcy’s coefficient in permeability, v= velocity of flow, h= differential head of water = h1-h2,
L= length of soil sample.