Darcy's law A description of the relationships among the factors that determine groundwater flow, expressed as an equation. At its simplest, Darcy's law states that Q = kIA, where Q is the groundwater flow, k the permeability of the rock, I the hydraulic gradient (i.e. gradient of the hydraulic head), and A the cross-sectional area through which flow occurs.

Darcy's law A description of the relationships among factors that determine groundwater flow, expressed as an equation. At its simplest, Darcy's law states that Q = kIA, where Q is the groundwater flow, k the hydraulic conductivity of the rock, I the hydraulic gradient (i.e. gradient of hydraulic head), and A the cross-sectional area through which flow occurs.